Résumés / Abstracts JNR2024

106 Résumés / Abstracts

Résumé/Abstract #1

Axe de recherche / Research Axis: Plateforme

Plateforme de tri cellulaire

DOMINIC BASTIEN

La plateforme de tri cellulaire du centre de recherche Cervo se spécialise dans l’analyse et le tri de neurones et de cellules isolées du système nerveux. Ces diverses sous-populations cellulaires peuvent être étudiées selon leurs propriétés physiques (taille, complexité intra-cellulaire) et optiques (présence de marqueurs fluorescents), et finalement triées. Nous utilisons un trieur BD-FACS AriaII capable de détecter 12 paramètres simultanément, dont 10 différents fluorochromes.

Soumis par / Submitted by: Bastien, Dominic

Affiliation: Centre de recherche CERVO

Résumé/Abstract #2

Axe de recherche / Research Axis: Plateforme

Services d’imagerie au CRCHUL et CRIUCPQ: de l’acquisition d’images à la visualisation graphique des résultats

Marc Bazin, Girish Shah, André Marette et Denis Soulet

Contexte : L’échantillonage des données en recherche est encore la clé de voûte de l’analyse. Pourtant, l’instrumentation moderne permet de produire une grande quantité de données, souvent sous forme d’images à haute résolution. Néanmoins l’analyse massive de ces données représente un obstacle en terme de coût et de temps que les laboratoires contournent par des techniques de stéréologie. Ainsi, la majorité des précieuses données instrumentales est ignorée faute de moyens pour les explorer.

Problème : La limitation contrôlée des données soumises à l’analyse est souvent source de faiblesse ou d’erreur dans la conclusion quantitative d’une étude (1). Cela aggrave le potentiel manque de puissance statistique des échantillons mesurés dans une expérience. De nombreuses études incluent maintenant des analyses systématiques et poussées qui surpassent les analyses classiques et viennent ainsi concurrencer les travaux analysés par des méthodes classiques.

Solution : Confier à des experts en analyse numérique le soin d’effectuer l’acquisition d’images et/ou les calculs sur les données massives issues de vos projets. Nous offrons nos compétences en analyses de masse dans les domaines de la biologie, de la physique et des mathématiques (modélisation, apprentissage automatique) pour produire résultats et graphes avec tests d’hypothèses. Nous disposons de nos propres équipements interconnectés, à savoir, un numériseur de lames, un microscope électronique à balayage, un cryo/ultramicrotome, un microscope électronique à balayage, deux systèmes d’imagerie in vivo et des stations de travail multi-CPU et multi-GPU.

Conclusion : Nous pouvons vous aider à acquérir vos données, à imager vos échantillons ou vos animaux et les analyser sans compromis avec des méthodes qui sont sur le point d’être incontournables. Nous traitons avec rigueur et moins de biais vos données et nous certifions quantitativement les résultats de votre publication à des prix planchers pour vos analyses de routine.

(1) John P. A. Ioannidis, PLOS Medicine (2005), “Why most published research findings are false”

Soumis par / Submitted by: Bazin, Marc

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #3

Axe de recherche / Research Axis: Plateforme

Banque de Cerveau humains

BERARD MORGAN, Parent Martin.
Centre de recherche CERVO, Département de Psychiatrie et Neuroscience, Faculté de Médecine, Université Laval, Québec, QC, Canada.

La banque de cerveaux du Centre de recherche CERVO a été créée en 1996 par le Dr. André Parent.

Cette banque de cerveaux a pour but d’aider les chercheurs à étudier l’organisation du cerveau humain ainsi qu’à mieux comprendre les causes des maladies qui affecte cet organe pour pouvoir éventuellement les prévenir et les traiter convenablement. Au cours des dernières décennies, la disponibilité du tissu cérébral a joué un rôle crucial dans la compréhension de certaines maladies neurologiques et psychiatriques. De plus, ce type de matériel a contribué de manière déterminante au développement de nouveaux traitements qui ont un impact majeur sur la qualité de vie des personnes qui souffrent de diverses maladies neuropsychiatriques
La banque du CERVO renferme du matériel provenant de plus de 600 cerveaux. Elle reçoit chaque année de nouveaux dons de cerveaux qui permettent d’étudier les maladies neurodégénératives (Parkinson, Alzheimer, Huntington, etc.) et psychiatriques (schizophrénie, troubles bipolaires, etc.) permettant la réalisation de travaux scientifiques majeurs dont les résultats sont publiés dans des revues scientifiques prestigieuses.

Tout individu, quel que soit son état de santé physique ou mental, peut décider du don de son cerveau, à condition que soit signé, par lui-même ou son représentant s’il est jugé inapte, un formulaire de consentement spécifique au don de cerveau. En effet, il faut savoir que le don de cerveau n’est pas visé par le formulaire à l’endos de la carte d’assurance-maladie. La participation du donneur est tout à fait volontaire et ne lui apportera aucun bénéfice financier. La personne (ou le représentant légal) demeure libre à tout moment de révoquer son don, sans avoir à fournir de justification et sans subir de préjudice.

Soumis par / Submitted by: Bérard, Morgan

Affiliation: Centre de recherche CERVO

Résumé/Abstract #4

Axe de recherche / Research Axis: Plateforme

La plateforme de vectorologie du centre CERVO : Des vecteurs viraux innovants pour une recherche de pointe

CHETOUI, NIZAR ; Boisvert, Marc; Dalangin, Rochelin; Simard, Jean-Nicolas; Paquet, Marie-Ève ainsi que tous les membres de la plateforme, Centre de recherche CERVO.

La plateforme de vectorologie du centre CERVO (PVCC) fait partie d’une initiative canadienne; la Plateforme Canadienne de neurophotonique (CNP). Elle développe plusieurs outils utilisés notamment dans les études faisant appel à l’optogénétique. La plateforme offre à la communauté de CERVO, de l’Université Laval ainsi qu’aux chercheurs québécois et canadiens des services en biologie moléculaire, en technologies de transfert de gènes et la production de vecteurs viraux. Depuis sa création en 2008, la plateforme n’a pas cessé d’innover et de varier ses offres de services. L’équipe est actuellement formée de plus de 13 professionnels performants et hautement qualifiés, digérée par Dre Marie-Ève Paquet.
La plateforme œuvre dans le domaine de transfert des gènes. Ces activités sont variées, dont la biologie moléculaire et le génie protéïque et la vectorologie. La plateforme produit divers vecteurs viraux, essentiellement les virus associés à l’adénovirus (AAVs), mais aussi les lentivirus et les virus rabiques. Dotée de plus de 20 sérotypes différents de AAVs, la plateforme fabrique aux alentours de 400 lots différents par années.
La plateforme consacre une partie de ses activités au développement des vecteurs viraux. Ainsi, plusieurs projets sont en cours pour découvrir de nous sérotypes de AAV, pour améliorer les capsides virales par ingénierie ainsi que le développement et l’amélioration des processus de fabrication et de contrôle qualité.
Des services supplémentaires comprennent le développement d’outils génétiquement modifiés permettant l’expression de protéines fluorescentes utilisées en imagerie du système nerveux. Par ailleurs, une grosse bibliothèque de senseurs moléculaires connues et récents sont disponibles.
Les services de la plateforme sont également accessibles à tous les chercheurs universitaires du monde entier. Ses activités sont destinées à démocratiser l’usage des vecteurs viraux au sein de la communauté scientifique particulièrement au niveau académique mais ses ambitions dépassent les membres de ce groupe particulier.
Forte d’un riche réseau de collaborateurs nationaux et internationaux qui permettent la distribution de leurs outils moléculaires à la fine pointe de la technologie, d’une vaste banque d’outils ainsi que de la capacité de procurer des outils personnalisés, la plateforme est un acteur important et se positionne pour devenir incontournable dans la niche des vecteurs viraux.

Soumis par / Submitted by: Chetoui, Nizar

Affiliation: Centre de recherche CERVO

Résumé/Abstract #5

Axe de recherche / Research Axis: Plateforme

Plateforme de production de cellules souches du CRCHU de Québec

Laurie Martineau
Sabrina Bellenfant
Jack Puymirat
François Gros-Louis

Grâce à l’expression forcée de 4 facteurs de transcriptions embryonnaires (OCT4, SOX2, KFL4 et c-MYC), une cellule somatique peut retourner à l’état pluripotente, c’est-à-dire, être capable de s’auto-renouveler et se différencier en toutes les cellules des 3 feuillets embryonnaires (endoderme, mésoderme et ectoderme). Ceci permet, entre autre, la modélisation de maladies dont les cellules ciblées sont difficilement, voir même impossible à obtenir via une biopsie. Ces cellules induites à la pluripotence (iPSC) peuvent aussi servir au développement et au criblage des drogues ainsi qu’à la médecine de précision.
La plateforme iPSC Québec se spécialise dans l’isolation et la reprogrammation de cellules somatiques en iPSC à partir de différentes sources (peau, sang, urine, etc.). Elle offre aussi la possibilité d’une formation pour l’utilisation de ces cellules. Avec près d’une centaine de reprogrammation à son actif, la plateforme iPSC est en mesure de fournir un service de haute qualité et ce, à prix avantageux à l’ensemble des chercheurs académiques du pays.
Son objectif est d’automatiser la production d’iPSCs afin d’en réduire d’avantage les coûts et d’augmenter la production, deux facteurs qui limitent leur utilisation.

Soumis par / Submitted by: Martineau, Laurie

Affiliation: CRCHU de Québec-UL, pavillon HEJ

Résumé/Abstract #6

Axe de recherche / Research Axis: Plateforme

Services de la Plateforme de Protéomique de Québec

Florence Roux-Dalvai, Victor Fourcassié, Clarisse Gotti, Antoine Lacombe-Rastoll, Pascaline Bories, Marie-Ève Thibeault et Arnaud Droit

La plateforme protéomique du Centre de Génomique de Québec, située au Centre de recherche du CHU de Québec – Université Laval (site du CHUL), vise à rendre la protéomique accessible à l’ensemble de la communauté scientifique par le biais de prestations de services ou de collaborations.

L’objectif principal de la plateforme est d’offrir aux chercheurs un service d’analyse de protéines par spectrométrie de masse de haute qualité grâce à ses instruments de dernière génération et à son personnel hautement qualifié.

L’ensemble des services proposés sont basés sur une approche personnalisée incluant une réunion préalable avec le client afin de choisir la stratégie analytique adaptée à la question biologique et au budget.

Les services incluent l’extraction de protéines à partir d’échantillons biologiques divers, l’identification et la quantification de protéines (de manière globale ou ciblée) ainsi que l’analyse de modifications post-traductionnelles.
En plus de la préparation d’échantillons et des analyses de spectrométrie de masse, la plateforme inclut dans son offre un traitement bioinformatique et statistique des données pour une visualisation et une utilisation immédiate des résultats obtenus.
L’équipement de la plateforme lui permet de prendre en charge aussi efficacement des projets incluant moins d’une dizaine jusqu’à plusieurs centaines d’échantillons.

Des tarifs préférentiels sont appliqués pour les clients du CHU, du Québec et du secteur académique.

Enfin, la plateforme de protéomique collabore étroitement avec les autres plateformes du Centre Génomique (notamment Plateforme de Bioinformatique et Plateforme de Séquençage NGS) afin de permettre la prise en charge efficace de projets multi-omiques et de projets de grande envergure.

À ce jour, plus de 100 000 échantillons provenant de plus de 350 clients différents ont été traités et analysés avec succès par la plateforme.

Pour plus de renseignements :
proteomique@crchudequebec.ulaval.ca
https://www.crchudequebec.ulaval.ca/services/proteomique/

Soumis par / Submitted by: Roux-Dalvai, Florence

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #7

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Chronic stress leads to region-specific changes in astrocyte gene and protein expression in male mice

BINDER, LUISA BANDEIRA; Bossé, Marie-Ève ; Redmond, Rebecca ; Lebel, Manon ; Menard, Caroline

Major depressive disorder (MDD) is a severe neuropsychiatric illness that will affect 20% of the population throughout their lifetime and is a major cause of disabilities according to the WHO. Unfortunately, 30-50% of individuals with MDD respond poorly to currently available treatment suggesting that causal mechanisms, such as increased circulating inflammation and neurovascular dysfunction, remain untreated. Alterations of the blood-brain barrier (BBB), formed by endothelial cells, pericytes and astrocytes, are observed in individuals with MDD and after exposure to chronic social defeat stress (CSDS), a mouse model of depression. Chronic stress is the main environmental risk factor to develop MDD and is associated with increased circulating levels of inflammatory cytokines namely interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha. Stress-induced BBB leakiness allows the passage of inflammatory mediators from the blood into the brain possibly contributing to neuronal dysfunction and depressive behaviors. Astrocytic morphological changes such as reduced end-feet coverage of blood vessels, occur in the MDD brain and are associated with inflammation and impaired function of these glial cells necessary for proper brain homeostasis. However, possible contributions to MDD pathogenesis and maladaptive stress responses remain to be elucidated. Male mice were subjected to 10-day CSDS producing two subpopulations: stress-susceptible (SS) animals which are characterized by depression-like behaviors and resilient (RES) mice behaving like unstressed controls. In males, CSDS induces BBB hyperpermeability mostly in the nucleus accumbens (NAc), a hub for mood regulation, reward processing, and stress responses. Reduced gene expression of connexin gap-junctions, linking neuronal and vascular activity, was observed in the NAc of SS, but not RES. Conversely, increased expression of growth factors and inflammatory markers was measured in the prefrontal cortex of RES animals, supporting compensatory mechanisms in this brain area possibly to counteract the deleterious effect of stress-induced inflammation. Functional measurements are ongoing to better define the role of astrocytes in the development of depression-like vs proper stress-coping behaviors. Altogether, these results suggest that astrocytes could actively contribute to susceptibility vs resilience to chronic stress exposure, and possibly MDD, in a brain region-specific manner.

Soumis par / Submitted by: Bandeira Binder, Luisa

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #8

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Effect of Antipsychotic Discontinuation or Maintenance on Recovery in Individuals with Remitted First-Episode Psychosis – A Systematic Review and Meta- Analysis of Randomized Controlled Trials

BÉCHARD, LAURENT 1,2,3; Desmeules, Charles 3,4; Bachand, Lauryanne 3; Huot-Lavoie, Maxime 3,4; Corbeil, Olivier 1,2,3; Anderson, Elizabeth 3; Brodeur, Sébastien 2,3,4; LeBlanc, Annie 4; Demers, Marie-France 1,2,3; Lauzier, Sophie 1; Roy, Marc-André 2,3,4.
1. Fac. de pharmacie, Université Laval; 2. IUSMQ, CIUSSS-CN; 3. Centre de recherche CERVO; 4. Fac. de médecine, Université Laval

Purpose
The optimal duration of antipsychotic treatment following remission of first episode psychosis (FEP) is uncertain, considering potential adverse effects and individual variability in relapse rates. This study aimed to investigate the effect of antipsychotic discontinuation compared to continuation on recovery in remitted FEP patients.

Methods
CENTRAL, MEDLINE (Ovid), Embase, and PsycINFO were searched on November 2, 2023, with no language restrictions. Randomized controlled trials (RCTs) evaluating antipsychotic discontinuation in remitted FEP patients were selected. The primary outcome was personal recovery, and secondary outcomes included functional recovery, global functioning, hospital admission, symptom severity, quality of life, side effects, and employment. Risk of bias was assessed using the Cochrane risk-of-bias tool 2, and certainty of evidence was evaluated with GRADE. Meta-analysis used a random-effect model with an inverse-variance approach.

Results
Among 2185 screened studies, 8 RCTs (560 participants) were included. No RCTs reported personal recovery as an outcome. Two studies measured functional recovery, and discontinuation group patients were more likely to achieve functional recovery (RR 2.19; 95% CIs: 1.13, 4.22; I2=0%; n=128), although evidence certainty was very low. No statistically significant differences were found in hospital admission, symptom severity, quality of life, global functioning, or employment between discontinuation and continuation groups; however, certainty of evidence was very low in most of these outcomes. The risk of bias appeared to explain the heterogeneity in the hospital admission rate. Considering only studies categorized as having moderate risk of bias, rather than high risk of bias, the hospital admission rate was higher in the antipsychotic discontinuation group (RR 3.54; 95% CIs: 1.28, 9.77; I2=0%; k=2, n=193).

Conclusions
Personal recovery was not reported in any antipsychotic discontinuation trial in remitted FEP. The observed positive effect of discontinuation on functional recovery came from an early terminated trial and an RCT followed by an uncontrolled period. Interpretation of these findings should be approached with caution due to the limited number of studies, the very low certainty of evidence, and the observed increase in hospital admission rates following antipsychotic discontinuation in some studies.

Soumis par / Submitted by: Béchard, Laurent

Affiliation: Centre de recherche CERVO

Résumé/Abstract #9

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Non-biased investigation of mPFC upstream circuitry in chronic stress in male and female mice

BLANC ÁRABE, LAILA; Benoit Labonté

The cortico-accumbal and cortico-tegmental pathways are involved in anxiety- and depressive-like behaviors induced by chronic stress. Previous studies indicate that chronic variable stress (CVS) induces morphological and functional changes affecting cortico-accumbal and tegmental pathways in a sex-specific fashion. Here, we investigated the pathway-specific upstream neural circuitry to understand which inputs may contribute to the effects observed in the mPFC of stressed males and female mice.
We used 21-day CVS to stress male and female mice. Inputs to neurons from the medial prefrontal cortex (mPFC) projecting either to the nucleus accumbens (NAc) or ventral tegmental area (VTA) were targeted through a trans-sectional viral approach combined with rabies trans-synaptic tracing. Neural activity patterns in stressed and control mice were assessed via c-Fos immunohistochemistry. We used whole brain light sheet microscopy to unbiasedly map every neuronal input projecting to either NAc- or VTA-projecting cells along with their activity patterns.
Our results show that the largest proportion of inputs to cortico-accumbal and tegmental pathways come from cortical areas. For instance, both pathways are densely targeted by orbital and agranular insular (AI) cortex. Limbic and brain stem areas such as the entorhinal area, periaqueductal grey, and amygdala (AMY) also project densely to both pathways. Our analysis of c-Fos expression in stressed mice showed sex and pathway-specific activation patterns. For instance, c-Fos expression was higher in neurons from the AI projecting to cortico-accumbal neurons in stressed females and to the cortico-tegmental pathway in stressed males. Opposite c-Fos expression was also found in basolateral AMY inputs to cortico-tegmental neurons in stressed males (lower) and females (increased).
Our study reveals the nature of the neuronal inputs to mPFC neurons projecting either to the NAc or the VTA and how they may be affected by stress in males and females. This provides potential targets to determine whether the impact of stress on the activity of the mPFC originates from different structures modulating the cortico-accumbal and tegmental pathways differently in males and females.

Soumis par / Submitted by: Blanc Árabe, Lail

Affiliation: Centre de recherche CERVO

Résumé/Abstract #10

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Toward quasi-noise free single-shot quantitative digital holography thanks to supervised learning

CHANIOT JOHAN, Moreaud Maxime, Larivière-Loiselle Céline, Haouat Mohamed, Crochetière Marie-Ève, Bélanger Érik, Marquet Pierre
Centre de recherche CERVO, Université Laval, 2601 Chemin de la Canardière, Québec, QC, G1J 2G3, Canada
Département de psychiatrie et neurosciences, Université Laval, Québec, QC, Canada,
Centre d’optique, photonique et laser, Université Laval, 2375 rue de la Terrasse, Québec, QC, G1V 0A6, Canada,
Département de physique, de génie physique et d’optique, Université Laval, Québec, QC, Canada,
IFP Energies nouvelles, Rond-point de l’échangeur de Solaize, BP 3, 69360 Solaize, France

In the study of major psychiatric disorders like schizophrenia, bipolar disorders and major depression, biophysical parameters, such as neuronal connectivity, are of utmost importance. The goal is to identify high-risk biomarkers that enable early recognition of at-risk children, to enable the use of primary preventive strategies. Peripheral cells are extracted from patients, transformed using reprogramming and differentiation techniques, into neurons with the patient’s genetic background. The analysis of neuronal development in culture involves the use of a specific imaging technique. Digital holographic microscopy (DHM) is a single-shot, non-invasive and label-free imaging technology that provides quantitative results. It is utilized for extracting the biophysical parameters of cell bodies, yet its sensitivity for neuronal connectivity is limited by coherent noise. To address this issue, the use of a multi-wavelength approach has been introduced, called polychromatic-DHM (P-DHM). This approach provides high-quality images, quasi devoid of coherent noise and revealing previously undetectable neuronal processes. However, the cost of P-DHM equipment and its complexity limit its widespread deployment. Simplification of this technique is required to enable its utilization on any conventional off-axis DHM.
For the first time, pairs of experimental images of neurons in culture, in particular DHM/P-DHM images of the same field of view, were used in a purely digital method called virtual P-DHM (v[P-DHM]), a convolutional neural network emulating P-DHM. The v[P-DHM] approach was tailored for our application, small database of quantitative images. Numerical analyses were conducted to verify the v[P-DHM]’s performance while it was compared to state-of-the-art methods. Finally, from a user’s standpoint, we offer assistance on extracting biophysical parameters and demonstrate the generalization of the v[P-DHM] to other off-axis DHM setups. Neuronal connectivity is now available for virtually all conventional off-axis DHM holders.

Soumis par / Submitted by: Chaniot, Johan

Affiliation: Centre de recherche CERVO

Résumé/Abstract #11

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Impact of stress-induced inflammation on blood-brain barrier transport systems

COLLIGNON ADELINE, Paton Sam, Dion-Albert Laurence, Lebel Manon, Ménard Caroline
CERVO Brain Research Centre, Québec, Canada
Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec, Canada

Major Depressive Disorder (MDD) is a serious chronic mental condition affecting over 280 million people worldwide. This complex and heterogenous illness can be triggered by environmental factors, such as stress. Unfortunately, 30-50% of individuals with MDD do not or respond poorly to available treatments targeting neuronal dysfunction. Intriguingly, resistance to treatment is often associated with an exacerbated immune response as measured by high levels of circulating proinflammatory cytokines such as interleukin (IL)-1, -6 and Tumor Necrosis Factor TNF-alpha (TNFa). Stress-induced inflammation in the brain and subsequent mood alterations may be promoted by the passage of peripheral immune mediators from the periphery into the CNS. Indeed, blood-brain barrier (BBB) alterations are observed following chronic stress exposure in mice, like in the chronic social defeat stress (CSDS) paradigm, a mouse model of depression, as well as in the MDD brain. The BBB is formed by endothelial cells, pericytes and astrocytes and while allowing nutrient exchange from the blood to the brain it also prevents entry of potentially harmful substances. Loss of BBB integrity may contribute to maladaptive stress responses and human depression, but the mechanisms leading to stress-induced BBB alterations and potential as a therapeutic target remain to be determined. We have preliminary data suggesting that caveolae-mediated transport of the BBB is altered after CSDS in male and female mice. To gain mechanistic insights and evaluate how stress-induced inflammation modulates BBB dynamic transport and cell signaling, I first took advantage of in vitro mouse and human BBB-related endothelial cell lines, that were subjected to an immune challenge to analyze BBB-linked genes expression at various time points. BBB permeability was also evaluated using transendothelial electrical resistance measurements. Plus, transport alterations were assessed in mice after a CSDS paradigm. Chronic stress exposure studies are ongoing with morphological studies but also magnetic resonance imaging (MRI) to assess both transport alterations and BBB integrity in depression. Overcoming the BBB to treat the brain has been a challenge for decades in psychiatry. Investigating BBB transport mechanisms involved in depression and its modulation in response to stress, inflammation and antidepressant treatments could lead to a better understanding of MDD and novel therapeutic avenues.

Soumis par / Submitted by: Collignon, Adeline

Affiliation: Centre de recherche CERVO

Résumé/Abstract #12

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Problem Gambling in Psychotic Disorders: A Systematic Review and Meta-Analysis of Prevalence

CORBEIL OLIVIER, Faculté de pharmacie, Université Laval; Anderson Élizabeth, École de psychologie, Université Laval; Béchard Laurent, Faculté de pharmacie, Université Laval; Desmeules Charles, Faculté de médecine, Université Laval; Huot-Lavoie Maxime, Faculté de médecine, Université Laval; Bachand Lauryann, École de psychologie, Université Laval; Brodeur Sébastien, Faculté de médecine, Université Laval; Carmichael Pierre-Hugues, Centre d’Excellence sur le Vieillissement de Québec; Jacques Christian, École de psychologie, Université Laval; Solmi Marco, Département de psychiatrie, Université d’Ottawa; Giroux Isabelle, École de psychologie, Université Laval; Dorval Michel, Faculté de pharmacie, Université Laval; Roy Marc-André, Faculté de médecine, Université Laval; Demers Marie-France, Faculté de pharmacie, Université Laval

Background: Problem gambling (PBG) has been found to be more prevalent in people with mental health disorders, such as substance use, bipolar, and personality disorders, than in the general population. Although individuals with psychotic disorders might also be expected to be more vulnerable to PBG, fewer studies have focused on this comorbidity. The aim of this review was to estimate the prevalence of PBG in people with psychotic disorders.

Methods: Medline (Ovid), EMBASE, PsycINFO (Ovid), CINAHL, CENTRAL, Web of science, and ProQuest were searched on November 1, 2023, without language restrictions. Correlational and experimental studies including individuals with psychotic disorders and reporting the prevalence of PBG were included. Risk of bias was assessed using the Joanna Briggs Institute critical appraisal for systematic reviews of prevalence data. The pooled prevalence of PBG was calculated using a fixed effects generalized linear mixed model.

Results: Of 1271 records screened, 12 studies (n = 3443) were included. The overall prevalence of PBG was 8.8% (95% CI, 7.9 – 9.8%, I2 = 68%). A lower prevalence was found in studies with a low risk of bias (5.6%, 95% CI, 4.4 – 7.0%, I2 = 0%, k = 5) compared to studies with a moderate risk of bias (10.5%, 95% CI, 9.3 – 11.8%, I2 = 41%, k = 7). No other subgroup differences were found.

Conclusions: Although more research is needed to identify those at increased risk for PBG, its relatively high prevalence warrants the implementation of routine screening for gambling in clinical practice.

Soumis par / Submitted by: Corbeil, Olivier

Affiliation: Centre de recherche CERVO

Résumé/Abstract #13

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Stress-induced sex-specific morphological and functional modifications in SST and PV interneurons in the mPFC

Marco D’Angelo, Karina Huot, Arturo Morraquin Rivera, Luca Pancotti, Christophe Proulx, Benoit Labonté

The medial prefrontal cortex (mPFC) is a major hub in the control and elaboration of stress responses. It does so by integrating and processing information from different brain regions before redirecting it to limbic structures controlling different aspects of emotional behaviors. Somatostatin (SST) interneurons and parvalbumin (PV) maintain a homeostatic balanced activity in the mPFC by controlling the inputs and the output of pyramidal cells, respectively. Work from our group suggests that chronic stress impairs the excitatory and inhibitory (E/I) balance in the mPFC. Here, we tested whether chronic stress changes with the morphological and functional properties of SST and PV GABAergic interneurons to disrupt the E/I balance in the mPFC of male and female mice.
We used 21 days of chronic variable stress (CVS) to induce an emotional stress response in PV-cre and SST-flpo transgenic mice. A trans-sectional viral approach was used to label SST and PV cells and assess neuronal complexity and functional alterations in stressed male and female mice. Connectivity and functional properties of both SST and PV GABAergic interneurons in male and female mice were addressed using the mGRASP viral approach.
Our results show a reduction in the complexity of SST interneurons in both male and female stressed mice compared to controls. On the other hand, we observed an increase in the number and complexity of PV interneurons in stressed female mice compared to controls, while stressed males exhibited reduced complexity compared to controls. Interestingly, this was accompanied by a concomitant increase in the dendritic arborization of PV interneurons in stressed female mice, while stressed male mice showed reduced dendritic arborization. SST interneurons showed a reduction of the dendritic arborization in stressed males and females compared to controls.
Our results provide a better understanding on how chronic stress might affect morphological and functional properties of SST and PV interneurons and their relationship with excitatory pyramidal neurons in modulating behavioral stress responses in a sex-specific way.

Soumis par / Submitted by: D’Angelo, Marco

Affiliation: Centre de recherche CERVO

Résumé/Abstract #14

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Impact of chronic stress on blood-brain barrier and stress responses in adolescence

DAIGLE, BÉATRICE (1), Solano, José L. (1), Lebel, Manon (2) and Menard, Caroline (1).
(1) Université Laval, Department of Psychiatry and Neuroscience, Quebec City (Canada)
(2) CERVO Brain Research Center, Quebec City (Canada)

According to the WHO, major depressive disorder (MDD) is the first cause of disability worldwide with a prevalence of 3-8% in adolescents. Adolescents are particularly vulnerable to the development of depression having the highest prevalence in global and Canadian population. Unfortunately, around 40% of depressed adolescents do not or respond poorly to available neuron-centric treatments suggesting that causal mechanisms remain untreated. Chronic stress is an important risk factor to development of MDD and it is associated with increased peripheric inflammation during adolescence. A prolonged rise in inflammatory molecules circulating in the blood can damage the blood-brain barrier (BBB), a highly selective barrier protecting the brain. Intriguingly, adolescents suffering from MDD have elevated plasma levels of markers associated with BBB permeability. Since adolescence is a critical time window for neurovascular development and maturation of the BBB, I investigated how chronic stress exposure impacts it. To do so, I took advantage of an emotional stress paradigm, social instability stress, which induced anxiety- and depression-like behaviors in adolescent male and female mice as measured with behavioral tests. I next explored the link between stress responses and expression of genes associated with BBB integrity and function. Transcriptomic profiling is currently complemented by immunostaining, microscopy and morphological analysis of the neurovascular network and BBB-related cells. Blood serum corticosterone and inflammation levels will be assessed by ELISA and a milliplex panel, respectively, to confirm stress-induced activation of the hypothalamic-pituitary axis and immune response and possibly highlight sex differences. Deciphering stress-induced immune and neurovascular alterations occurring during adolescence could allow a better comprehension of the biological mechanisms underlying the development of depression in this understudied population.

Soumis par / Submitted by: Daigle, Béatrice

Affiliation: Centre de recherche CERVO

Résumé/Abstract #15

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Interaction between a high fat diet and stress: effect on depression in relation to the gut microbiome-endocannabinoidome axis

GIADA GIORGINI 1245, Charlène Roussel 35, Jacob Lessard-Lord 35, Nadine Leblanc 135, Elizabeth Dumais 145, Nicolas Flamand 125, Cristoforo Silvestri 1235, Vincenzo Di Marzo 12345

1Centre de Recherche de l’Institut de Pneumologie et Cardiologie de l’Université Laval
2 Département de médecine, Faculté de Médecine, Université Laval, Québec G1V 4G5, Canada.
3 Institut sur la Nutrition et les Aliments Fonctionnels, Centre NUTRISS, Québec G1V 0A6, Canada.
4 Joint International Unit between the National Research Council (CNR) of Italy and Université Laval on Chemical and Biomolecular Research on the Microbiome and its Impact on Metabolic Health and Nutrition (UMI-MicroMeNu), Institute of Biomolecular Chemistry, CNR, Pozzuoli, Italy.
5 Canada Research Excellence Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND), Université Laval, Québec G1V 0A6, Canada.

Objectives/Background: Depression is a widespread neuropsychiatric disorder that can affect the entire population, regardless of age and socioeconomic conditions. Several studies have linked the pathophysiology and regulation of mood disorders, particularly depression, with the modulation of the endocannabinoid system and its expansion to the endocannabinoidome (eCBome). The composition of the gut microbiota influences the activity of the eCBome, while the eCBome is involved in the regulation of the microbiota. In recent years, it has been shown that a high-fat diet (HFD) is associated with an increase in the tone of the eCBome, concomitant with a deregulation of the gut microbiota. In addition, HFD can lead to depression, although the causal mechanisms are not yet clear. In our study, we aimed to determine the interactions between a HFD and depression caused by chronic stress in the context of the gut-brain axis.
Methods: We employed a 9-week standardized chronic unpredictable mild stress (UCMS) model to induce depression in two groups of mice fed either a low-fat, low-sucrose diet (LFLS) or a high-fat, high-sucrose diet (HFHS). Throughout the study, fecal samples were collected, and body composition analyses were performed at week 0, week 5, and week 9 to assess the composition of the microbiota (16S gene amplicon sequencing) and to monitor changes in total lean and fat mass over time. At week 9, behavioral tests were performed to assess depressive and anxiety-like symptoms. Gene expression analysis was performed to assess changes in blood-brain barrier (BBB) integrity and inflammation, and neurotransmitter and eCBome mediator levels were measured in the brain and gut. In addition, short-chain fatty acids were analyzed in the feces.
Preliminary results: We confirmed the presence of depressive-like signs in the stressed group. In addition, we showed that an HFHS diet exacerbated depressive-like symptoms. Additionally, we found that using multivariate analysis, stress had a major impact on gut microbiota composition as compared to diet. In particular, Bifidobacterium, decreased with stress particularly in the HFHS group, suggesting that this taxon is associated with HFHS-induced exacerbation of depression. Accordingly, butyric acid, a product of this genus, was decreased in the HFHS stress group compared to the LFLS stress group, suggesting that it could mediate the possible role of Bifidobacterium in the development of depression. In addition, Tuzzerella and Anareoplasmaincreased only in the HFHS diet stress group, suggesting that this genus might be a key player of the development of the higher depressive-like symptoms found in HFHS stress group.
Perspectives: The measurement of the endocannabinoidome is ongoing, and the results will be shared during the presentation.

Soumis par / Submitted by: GIORGINI, GIADA

Affiliation: CRIUCPQ-UL

Résumé/Abstract #16

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Neonatal exposure to polydrugs, the zebrafish as a key model.

HERMANT LISE, Bossé Gabriel, CERVO Brain Research Centre

Drug abuse during pregnancy is a growing social and medical concern as it endangers both the mother and the child. Such consumption can lead to several consequences such as birth defects, neonatal abstinence syndrome or even death and can also have detrimental long-term effects. Indeed, it has been reported that neonatal polydrug exposure can induce cognitive impairments, affect the attention or even lead to adverse speech and language outcomes and to sleeping difficulties.

The effects of single drug consumption, such as nicotine and ethanol, are better understood. However, single-drug abuse is not representative of reality. Indeed, several studies have shown that pregnant women consuming drugs are usually taking multiple ones at the same time. For instance, in 2017, among women using marijuana, 74 % of them were also smoking tobacco. According to another study, more than 90 % of individuals consuming opioids reported consuming at least one other non-opioid drug in the past month.

So far, the effects of polydrug abuse on mothers’ and children’s health are poorly understood, and there is currently no treatment to prevent or reverse its long-term effects.

Thanks to its quick development and the simplicity of pharmacologically treating it, Zebrafish is emerging as a critical model in the study of substance use disorder as we can model different aspects of substance abuse (combination of substances, dose-response, time of exposure…). Our lab is focusing on three main drugs: morphine (opioid of reference used in the treatment of pain), nicotine and alcohol. We are interested in the effects of those drugs after prenatal exposure on cognitive functions and behavior in the short (young) and long (adult) term. After finding the proper doses for each drug, we are combining them to be able to describe some effects at different levels (going from behavior to more integrated mechanisms).

Our preliminary data indicate that substance exposure has several effects on the zebrafish, such as hypersensitivity, increased anxiety and even sleep disruptions. Furthermore, depending on the drug used and whether it is associated with one or several other drugs, the phenotypes observed are different. Thus, the consumption of one drug or several ones seems to have different effects on the nervous system, which deserve to be more deeply invested.

Soumis par / Submitted by: Hermant, Lise

Affiliation: Centre de recherche CERVO

Résumé/Abstract #17

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Microscopie holographique numérique polychromatique : une nouvelle approche pour une meilleure visualisation des cellules vivantes en action

LARIVIÈRE-LOISELLE, CÉLINE; Haouat, Mohamed; Bélanger, Erik et Marquet, Pierre
Centre de recherche CERVO

Dans l’objectif final de découvrir des biomarqueurs associés aux grands troubles psychiatriques, cette recherche explore l’utilisation de la microscopie holographique numérique (DHM), et plus précisément sa version améliorée, la DHM polychromatique (P-DHM).

La DHM a joué un rôle clé dans plusieurs études en biologie cellulaire. Néanmoins, le niveau de cohérence de la source lumineuse utilisée pour générer les images peut induire du bruit, rendant parfois certains détails difficiles à identifier. Pour résoudre ce problème, nous avons récemment développé une approche novatrice : la DHM polychromatique (P-DHM). Cette technique nous permet d’obtenir des images presque dénuées de bruit.

Forts de ces résultats prometteurs, nous avons amélioré la technologie afin d’observer des cellules vivantes avec une résolution temporelle. Cela nous donne la possibilité de capturer des processus cellulaires dans leurs moindres détails, tant sur le plan structurel que dynamique. Notre appareil intègre un DHM fondé sur un interféromètre de Mach-Zehnder et un laser à longueur d’onde ajustable. Cet équipement nous permet de produire des hologrammes à diverses longueurs d’onde, que nous reconstruisons numériquement pour créer des images quasi exemptes de bruit.

Nous avons d’abord automatisé le procédé pour filmer des événements biologiques qui se produisent sur une échelle de temps plus lente (quelques heures). Grâce à cela, nous avons pu observer les mouvements au sein des fines connexions qui se forment entre les neurones, une tâche auparavant difficile à cause du bruit. Nous pouvons aussi observer le trafic intracellulaire, soit le déplacement des organites, et les changements morphologiques dans certaines cellules du système nerveux. Nous nous employons maintenant à visualiser des processus cellulaires plus rapides grâce à une approche d’automatisation électronique en cours de développement.

Soumis par / Submitted by: Larivière-Loiselle, Céline

Affiliation: Centre de recherche CERVO

Résumé/Abstract #18

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Transcriptional dissection of symptomatic profiles across the brain of men and women with depression

Samaneh Mansouri, André M. Pessoni, Arturo Marroquín-Rivera, Eric M. Parise, Carol A. Tamminga, Gustavo Turecki, Eric J. Nestler, Ting-Huei Chen & Benoit Labonté

Major depressive disorder (MDD) is one of the most important causes of disability worldwide. While recent work provides insights into the molecular alterations in the brain of patients with MDD, whether these molecular signatures can be associated with the expression of specific symptom domains remains unclear. Here, we identified sex-specific gene modules associated with the expression of MDD, combining differential gene expression and co-expression network analyses in six cortical and subcortical brain regions. Our results show varying levels of network homology between males and females across brain regions, although the associations between these structures and the expression of MDD remain highly sex specific. We refined these associations to several symptom domains and identified transcriptional signatures associated with distinct functional pathways, including GABAergic and glutamatergic neurotransmission, metabolic processes, and intracellular signal transduction, across brain regions associated with distinct symptomatic profiles in a sex-specific fashion. In most cases, these associations were specific to males or females with MDD, although a subset of gene modules associated with common symptomatic features in both sexes were also identified. Together, our findings suggest that the expression of distinct MDD symptom domains is associated with sex-specific transcriptional structures across brain regions.

Soumis par / Submitted by: mansouri, samaneh

Affiliation: Centre de recherche CERVO

Résumé/Abstract #19

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Local transcriptomic analysis of ventral tegmental dopaminergic projections after chronic social defeat stress in mice

MOREIRA PESSONI, ANDRÉ – CERVO Brain Research Centre, Quebec, QC, Canada
Quessy, Francis – CERVO Brain Research Centre, Quebec, QC, Canada
Metzakopian, Emmanouil – University of Cambridge, Cambridge, United Kingdom
Levesque, Martin – CERVO Brain Research Centre, Quebec, QC, Canada
Labonté, Benoit – CERVO Brain Research Centre, Quebec, QC, Canada

Depression is a mental disorder with a global impact, exhibiting differing effects on males and females. It manifests through diverse behavioural symptoms, notably featuring reward-related deficits, like anhedonia. Comorbidities with anxiety are common and over 20% of individuals with mood or anxiety disorders may also face drug addiction, suggesting potential overlap in affected brain regions. However, the mechanisms behind this sexual dimorphism and its impact on the reward system remain poorly understood. Therefore, assessing transcriptional alterations within ventral tegmental projections after stress is crucial.
To study dopaminergic neurons, mice of the DAT-IRES-cre strain were subjected to a 10-day chronic social defeat stress paradigm. Their social-avoidance behaviour was subsequently assessed using the social interaction test, categorizing them as susceptible or resilient. Brain tissue from the ventral tegmental area (VTA) and its axonal projections to the prefrontal cortex (PFC) and nucleus accumbens (NAc) underwent immunoprecipitation and RNA purification before Ribotag RNA sequencing. Next, we employed a pipeline for differential expression, transcriptional overlap and gene co-expression network analyses, integrating them with gene ontology and differentially expressed gene enrichment analyses.
We found that the local transcriptional setting significantly varies between resilient and susceptible and between male and female animals. Moreover, the distinctions driven by sex and phenotype between cell bodies in VTA and its projections are even more pronounced. At the gene network level, we identified 13 modules, some grouping genes associated with dopamine response, synaptic signalling, and axon development. Notably, hub genes like Calm1, Syt1, and Nrg1 emerged as potentially interesting findings.
Our analysis reveals striking differences in the expression of genes within different areas of VTA neurons that project to PFC and NAc and in their gene network organization, in sex- and phenotype-specific fashion. Understanding these differences could provide insights into the molecular mechanisms linking stress to the reward pathway, and in the future between depression and its symptoms and phenotypes.

Soumis par / Submitted by: Moreira Pessoni, André

Affiliation: Centre de recherche CERVO

Résumé/Abstract #20

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

GATOR1 Mutations Impair PI3 Kinase-Dependent Growth Factor-Signaling Regulation of mTORC1

MULLER MAELINE ; Jasmine Bélanger ; Imane Hadj-Aissa ; Chantelle Sephton ; Paul Dutchak
Department of Psychiatry and Neuroscience, CERVO Brain Research Center, Université Laval

The mammalian target of rapamycin (mTOR) signaling pathway is involved in multiple processes including cell growth, protein synthesis or autophagy. mTOR signaling pathway is widely involved in the regulation of physiological processes in the brain and disruption of this pathway have been associated with multiple neurological diseases such as epilepsy.
The mTORC1 complex functions to integrate intracellular amino acid content and growth factor signaling in the cell. GATOR1 is a cytoplasmic protein complex formed by DEPDC5, NPRL2 and NPRL3 and respond to a low level in amino acid by hydrolyzing the RAG-GTP and inhibit mTORC1 activity. When GATOR1 is not functional and unable to play its inhibiting role, mTORC1 is permanently activated by GTP-bound RAGs even in presence of a low level of amino acid in the cell. Mutations that impair the functionality of GATOR1 complex have been associate to a wide spectrum of focal epilepsy suggesting that too high activation of mTORC1 is detrimental for the brain.
Both the localization of mTORC1 on lysosome via amino acid pathway and activation of the complex by the small GTP bound protein Rheb, via the PI3K/AKT pathway in response to growth factor, is required to have a full activation of mTORC1. It is still unclear how and why the balance between these two pathways is regulated depending on nutriment availability, and cell type specific growth factor signaling pathways. Thus, although a dysfunction in GATOR1 function directly impacts the amino acid sensing role of mTORC1, few studies have focused on the impact of these mutations on cross-talk with major growth factor signaling pathways. This include the PI3K/AKT pathway, an important signaling cascade that responds to growth factors, such as Brain-derived neurotrophic factor (BDNF), which plays an important role in neuronal survival and growth.
Here we investigate the coordinate regulation of mTORC1 by the GATOR1 amino acid-dependent signaling pathway and PI3K/AKT pathways to develop a mechanistic understanding of this pathway in epilepsy linked GATOR1 dysfunction.

Soumis par / Submitted by: Muller, Maéline

Affiliation: Centre de recherche CERVO

Résumé/Abstract #21

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Fibroblastes et Microscopie holographique numérique : un duo prometteur pour un biomarqueur de la bipolarité

PARANT PAUL, Boutin Audrey-Anne, Paquet-Mercier François, Thibault Simon, Marquet Pierre, COPL, Centre de Recherche CERVO

Près de 1 individu sur 200 développera au cours de sa vie un trouble bipolaire. Pourtant, le diagnostic de ce trouble reste ancré dans les pratiques du siècle dernier : le ou la praticienne se fie toujours à des symptômes cliniques qu’elle interprète à travers le prisme de son expérience. Il n’est pas rare que la bipolarité soit confondue avec une dépression profonde, ce qui peut entraîner des implications graves, car la prise en charge diverge considérablement selon le diagnostic, ce qui aboutit parfois à des hospitalisations prolongées et à des situations critiques.

Puisqu’il n’est éthiquement pas question de prélever directement les neurones d’une personne bipolaire, l’équipe du Docteur Marquet étudie plutôt des cellules plus accessibles : les fibroblastes. Ces cellules de la peau présentent une proximité avec les cellules neuronales et partagent une même origine embryonnaire. Elles sont récupérées à partir d’une biopsie de peau, et mise en culture. La structure et la dynamique des fibroblastes sont analysées très finement et de manière non invasive par microscopie holographique numérique (DHM).

La DHM permet une mesure précise du retard de phase causé par un échantillon, de manière temporelle et quantitative. Cette mesure se présente sous la forme d’une « carte de retard de phase » pour un champ de vue pouvant contenir plusieurs dizaines de cellules. C’est elle qui nous permet d’obtenir une évaluation très précise de la structure et de la dynamique pour chacune des cellules du champ de vue, durant toute l’expérience. Toutefois, les DHM commerciaux, bien que précis, sont onéreux. C’est pourquoi nous avons développé un imageur plus abordable, robuste, avec de larges champs de vue, tout en conservant la résolution afin d’effectuer nos mesures de manière automatisée. Pour ce faire, un modèle de simulation numérique a été mis en place sur le logiciel de conception optique Zemax, est un prototype est en cours de réalisation par la plateforme technologique Sentinelle Nord.

Grâce à cette analyse DHM sur des cellules facilement prélevable, un biomarqueur spécifique à la maladie bipolaire a été identifié au sein d’une cohorte de recherche d’une centaine de participants en Suisse. Ce biomarqueur est actuellement en cours de validation à travers la réalisation d’une étude clinique impliquant 100 participants, et comprenant des patients fréquentant les services du CIUSSS-CN.

Soumis par / Submitted by: Parant, Paul

Affiliation: Centre de recherche CERVO

Résumé/Abstract #22

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

The Smart Cage: Real-time assessment of mice weight and behaviour

Valérie Pineau Noël, Nathan Bérubé, Mireille Quémener, Caroline Ménard et Daniel C. Côté

Daily mice weighting is sometimes required to assess the animal’s health. However, measuring the animal’s weight and evaluating the animal’s behaviour, while essential, require the interaction of an experimenter, which could change the animal’s behaviour by inducing stress and jeopardizing its wellbeing. Also, the whole process is time-consuming for the experimenter, preventing continuous data acquisition. Evaluating the behaviour in the animal’s home cage, as well as continuously following the food intake, the water intake and the animal’s weight, could provide more accurate information on its state of mind and habits.

We propose the use of an automated and customizable mouse home cage to monitor the weight of the animal and its water consumption. Automated mouse home cage systems already exist on the market, but they are not customizable, and they are too expensive to be supplied in multiple copies for biological experiments done with many animals. Our smart cage is easily adaptable to any home cage, low-cost, and user-friendly for non-experts in electronics and programming. We take advantage of load cells and 3D-printed platforms to create a mosaic of scales that cover the whole surface of a normal mouse cage. A load cell is used to weigh the water bottle in real-time and a capacitive touch sensor is used to estimate the number of drinking events. We aim to measure grooming and sleeping habits in addition to follow weight loss in real-time. This automated mouse home cage could provide a better overview of a resident animal’s behavioural changes without the need for human interference.

Soumis par / Submitted by: Pineau Noël, Valérie

Affiliation: Centre de recherche CERVO

Résumé/Abstract #23

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Investigating the impact of stress on mPFC-NAc and mPFC-VTA pathways: insights into neuronal dynamics and coordinated activity

POURMOUSAVI, MARZIYEH: CERVO Brain Research Centre, Quebec, QC, Canada; Faculty of Sciences and Engineering, Université Laval
Charry Sánchez, Jesús David: CERVO Brain Research Centre, Quebec, QC, Canada; Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval
Labonté, Benoit: CERVO Brain Research Centre, Quebec, QC, Canada; Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval
Desrosiers, Patrick: CERVO Brain Research Centre, Quebec, QC, Canada; Department of Physics, Physical and Optical Engineering, Faculty of Science and Engineering, Université Laval

The expression and consolidation of complex behaviors is mediated by the activity of distinct neuronal networks in the brain. The medial prefrontal cortex (mPFC) integrates various sensory and motivational information which is then sent out to several output brain regions guiding adaptive behaviors to emotional cues. Substantial lines of evidence suggest that cortically driven dysregulation of subcortical circuits, may underlie the expression of depressive behaviors. One of the reasons that causes dysregulation of these subcortical circuits is prolonged stress. To find the effect of stress on neural activity, we use fluorescence signals acquired via in vivo two-colors Ca2+ imaging in freely behaving animals subjected to prolong stress. We start by applying different algorithms to process Ca2+ fluorescent signals from two neuronal populations independently and then merge them to evaluate synchronized activity. Neuronal activity will be paired to behavioral measures time-stamped with Ca2+ signals. We use probabilistic methods to classify neuronal activity patterns associated with different stress types and behavioral responses in both sexes. Finally, we will apply network theory to create neuronal networks integrating the activity of different neuronal populations in the brain. The dynamic activity of these networks will be evaluated through the duration of stress. Different measures will be applied to evaluate how different stress types induce behavioral alterations by interfering with the activity neuronal networks in the mPFC of male and females. We will finally use machine learning approaches to develop an in-silico model capable of predicting neuronal responses under specific environmental or behavioral conditions.
Overall, this project will provide significant insights into how stress signals are encoded by the different neuronal populations in the mPFC to modulate the expression of specific behavioral responses in males and females. By doing so, we will develop a series of innovative tools and approaches for the processing and analyses of complex Ca2+ signals evaluated over prolonged periods of time.

Soumis par / Submitted by: Pourmousavi, Marziyeh

Affiliation: Centre de recherche CERVO

Résumé/Abstract #24

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

ERP correlates of resisting craving in adults with tobacco use disorders

RAYAS, UZIEL 1,2,3, Renauld Emmanuelle 1,2,3, Fecteau Shirley 1,2,3

1. Department of Psychiatry and Neurosciences, Faculty of Medicine, Université Laval, Quebec City, Canada
2. CERVO Brain Research Centre, Quebec City, Canada
3. Centre intégré universitaire de santé et de services sociaux de la Capitale-Nationale, Quebec City, Canada

Tobacco use disorders (TUD) is the largest premature death in the world. While most adults with TUD have attempted to quit, only less than 10% successfully quit for at least 6 months. Craving is one of the main causes of smoking relapses. Thus, one of the key factors to prevent relapses is the ability to resist craving. Event-related potentials (ERP) have been extensively studied using cue-provoked paradigms. For instance, smokers display enhanced P300 and early Late Positive Potential (LPP) amplitudes when presented with tobacco-related stimuli or asked to imagine how pleasant it would be to smoke. However, little is known on ERP related to resisting craving, which seems important to investigate since such activity might represent treatment target to promote smoking cessation. The main goal of this work was to investigate the ERP correlates of resisting craving as compared to craving during a cue-provoked paradigm. Fifty-four adults with TUD (DSM-5) completed the study. They were assessed on tobacco dependence, anxiety, and impulsivity. Craving ratings were collected on visual analog scales. EEG was recorded using 64 Ag–AgCl electrodes (Brain Products GmBh). We compared ERPs between Craving and Resisting craving conditions. Results revealed that EPN, P300, and early LPP were smaller during the Resisting than the Craving conditions. Further, anxiety level positively correlated with the P300 amplitude and impulsivity positively correlated with early LPP during the Resisting condition. We pursue this line of work by targeting these ERPs with non-invasive neuromodulation to help patients with TUD resist craving.

Soumis par / Submitted by: Rayas, Uziel

Affiliation: Centre de recherche CERVO

Résumé/Abstract #25

Axe de recherche / Research Axis: 4. Stress, sommeil et santé mentale / Stress, sleep and mental health

Mitochondrial recalibration as a novel mechanism to explain early life-induced stress causing sleep apnea in adult mice

Lida Sanchez Sanchez
Aida Bairam
Edith Schneider
Jorge Soliz

Early-life stress contributes to the dysfunction of the adult respiratory neural control system. Our studies in mice have shown that neonatal maternal separation (NMS, a protocol used to study neonatal stress in the laboratory) increases postnatal corticosterone release, and apnea episodes in adult male animals. Because: 1) oxidative stress and inflammation are dependent on mitochondrial function and are features of sleep apnea at the cellular level, and 2) NMS impairs neural function of the nucleus tractus solitarius (NTS, involved in respiratory rate integration/modulation) and the rostral ventrolateral medulla (VRG, responsible for cardiorespiratory regulation), we hypothesized that NMS induces long-term impairment of mitochondrial functions in the NTS and VRG, ultimately leading to dysfunctional respiratory control. Samples were collected from 4-month-old male and female mice exposed (or not – control) to NMS from postnatal days 3 to 12. Activation of complexes I, II, I+II and inhibition of complex IV, were assessed in our Oxygraph-2K system (OROBOROS). Our results show that NMS leads to exacerbated activation of mitochondrial complexes I, II, I+II and IV in the VRG, and complexes I, I+II and the LEAK state in the NTS of male mice only. We conclude that impaired mitochondrial function in the nervous control of the respiratory system during early postnatal development may lead to respiratory dysfunction in adulthood.

Soumis par / Submitted by: Sanchez Sanchez, Lida

Affiliation: IUCPQ

Résumé/Abstract #26

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Rhythmic visual stimulations drive deep brain activity and boost attention performance and involuntary learning

BERNIER, MARIE-FRÉDÉRIQUE (1, 2); Martineau, Laurence (3); Levasseur, Paule (3); Borderie, Arthur (1, 2); Blanchette, Isabelle (1, 2); Blumenthal, Anna (1, 2); Albouy, Philippe (1, 2); Hoyer, Roxane S. (1, 2)

1- CERVO Research Centre
2- Université Laval
3- CHU de Québec

Background: Oscillations refer to the rhythmic fluctuations of the brain activity. In an echoed manner, oscillations can synchronize their frequency to environmental sensory rhythms (e.g., repetitive visual stimuli). This brain resonance has been observed within cortical areas, but the extent to which it propagates deeper into the brain has not yet been studied. We manipulated the emotional valence of visual rhythmic stimulations (RVS) and used i) stereotactic electroencephalographic (sEEG) recordings in focal drug-resistant epileptic patients to investigate whether oscillatory resonance propagates within subcortical brain areas, and ii) behavioral measurements in healthy adults to enlighten the causal effects of this phenomenon on attention and involuntary learning.
Method: To test our hypothesis that the frequency and nature of RVS can be used to drive subcortical brain oscillations, we first recorded the brain activity in 3 epileptic patients implanted with sEEG while presented with 2min 5Hz neutral (rope) or threatening (snake) visual stimulations, and during a rest period. Additionally, 27 healthy adults performed a visual attention (deviance detection) task, wherein all the trials were preceded by either a 4s period with 1) no RVS (control), 2) neutral RVS or 3) threatening RVS. Subsequently, participants performed an ‘unexpected’ memory task consisting in the discrimination of targets (used in the attention task) from distractors.
Results: Results from sEEG connectivity analyses in epileptic patients suggest that both neutral and threatening RVS entrain brain activity at the stimulation frequency in different nodes of a subcortical network: 5Hz oscillatory resonance is observable in the amygdala, the hippocampus, the insula and the orbitofrontal cortex (OFC). This resonance phenomenon is particularly important during the threatening RVS in the insula and the OFC. Behavioral results in healthy adults indicate that the 5Hz RVS (neutral and threatening) increases target detection speed compared to the no RVS condition. Interestingly, recognition accuracy is enhanced only in trials preceded by threatening RVS. Overall, we report the first evidence that emotional valence of RVS can be manipulated to non-invasively entrain activity in specific subcortical brain networks. In healthy participants, 5Hz RVS boost deviance detection speed, while threatening 5Hz RVS bolster involuntary learning, likely by facilitating connectivity between the insula and OFC.

Soumis par / Submitted by: Bernier, Marie-Frédérique

Affiliation: Centre de recherche CERVO

Résumé/Abstract #27

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Overcoming performance constraints with deep learning for microscopy of neuronal structures

BOUCHARD CATHERINE, Vincent David, Bellavance Jean-Michel, Wiesner Theresa, Ollier Antoine, Lavoie-Cardinal Flavie, Gagné Christian

Fluorescence microscopy techniques are continuously developed to visualize neuronal structures at the nanoscale, each optimizing an experiment-specific objective in terms of either the spatial resolution, temporal resolution, signal-to-noise ratio, light exposure, or multi color capacity. There is a limit to the achievable performance of these systems; a method that is engineered to maximize a set of parameters inevitably makes tradeoffs for one or more of the other parameters. We propose two deep learning methods that can extend the achievable performance beyond the limits defined by this space of tradeoffs, allowing new acquisition schemes for studying the nanoscale dynamics in living neurons.

The first method stretches the space of tradeoffs towards a better spatial resolution without compromising on light exposure. A task-assisted generative neural network (TA-GAN) enhances the resolution of low-light exposure acquisitions (e.g confocal) to match the resolution obtained with a more photo-damaging method (e.g STED). During the acquisition, the TA-GAN generated images inform the user on the nanometric content of the field of view without requiring the acquisition of a super-resolved image. This information is used to automatically select time points of interest for the visualization of the activity-dependent remodeling of F-actin nanostructures. Using the TA-GAN allows to optimize the acquisition sequence of STED images, enabling to reduce the light exposure, making it possible to visualize the dendritic F-actin remodeling for the first time in living neurons.

The second method exploits the multi-dimensionality of the acquired information to expand the space of tradeoffs towards a better multichannel capacity, temporal resolution and signal-to-noise ratio, without compromising on the spatial resolution or the light exposure. By measuring the excitation-emission delay of the detected photons, the photon can be assigned to a fluorescent protein among a set of emitters present in the sample. The method we propose is a multi-dimensional neural network that processes simultaneously all dimensions of the image (temporal and spatial). The method allows the simultaneous visualization of different synaptic proteins from a single acquisition.

Soumis par / Submitted by: Bouchard, Catherine

Affiliation: Centre de recherche CERVO

Résumé/Abstract #28

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Dopamine release encodes contrasting reinforcement signals across the dopaminergic system

BOUCHARD, SARAH-JULIE (1), Joël Boutin (1), Catherine Desbiens (1), Léa-Maude Gauthier (1), Yizhou Zhuo (3), Yulong Li (3), Martin Lévesque (1,2), Vincent Breton-Provencher (1,2)
(1) CERVO Brain Research Center, Quebec City, Quebec, Canada
(2) Psychiatry and Neurosciences Department, Université Laval, Quebec City, Quebec, Canada
(3) State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China

The dopaminergic system facilitates associative learning and motivated behaviors by signaling reward expectation and reinforcement valence – appetitive versus aversive – within the brain. According to previous studies, this reinforcement signaling is heterogeneously represented by dopaminergic neurons, suggesting a distributional coding of reinforcement within the dopaminergic system. However, it remains unclear how the dopamine signals for expectation and valence interact together within this code in various brain regions. Moreover, the extent by which fluctuations in dopamine levels track reinforcement signals, previously measured with somatic and axonal activity, is poorly understood, especially due to increasing evidence for target-specific mechanisms that control dopamine release. Here, we used an improved fluorescent dopamine sensor to record dopamine signals associated with reward predictions and stimulus valence in multiple pathways of the dopaminergic system in mice. Using this approach, we compared dopaminergic signals across various locations of the mesolimbic pathway (including subregions of the nucleus accumbens, olfactory tubercle, amygdala), the nigrostriatal pathway (dorsal and tail striatum), and mesocortical pathway (medial prefrontal cortex). Our preliminary findings indicate that the delivery of a rewarding stimulus triggered dopamine release in all the output regions. Importantly, the encoding of reward expectation is heterogeneously distributed across the various targets. Specifically, the relationship between reward prediction error and dopamine release was the strongest in various regions of the mesolimbic pathway, while it was the weakest in the mesocortical pathway. Additionally, when measuring the change in dopamine levels following an aversive stimulus, we observed that dopamine release peaked in regions where the encoding of reward expectation by dopamine was the lowest, except for dopamine signals in the basolateral amygdala. Together, our findings provide evidence of contrasting reinforcement signals across the primary targets of dopaminergic pathways through which dopamine release supports learning.

Soumis par / Submitted by: Bouchard, Sarah-Julie

Affiliation: Centre de recherche CERVO

Résumé/Abstract #29

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Investigate chloride cotransporter KCC2 expression dynamics in classic Rett Syndrome

CABANA JENNIFER, Watters Valérie, Fort Victoire, Barbeau Annie, Hussein Samer, Godin Antoine. CRCHU de Québec – Université Laval, Québec , QC, Canada. Centre de recherche CERVO – Université Laval, QC, Canada.

Neurodevelopmental disorders such as Rett syndrome and autism spectrum disorder (ASD) are characterized by an imbalance in chloride ion (Cl-) homeostasis. This disruption of Cl- homeostasis is often associated with a neuronal inhibition disorder related to the function of gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the brain. This balance is heavily regulated by the expression of two cotransporters, the NKCC1 (Na-K-Cl cotransporter, importer of Cl-) and the KCC2 (K-Cl cotransporter, exporter of Cl-). To investigate neurodevelopmental disorders related to Cl- transport, we focused on KCC2, the cotransporter specific to neurons in the central nervous system (CNS). Its expression increases during healthy neurodevelopment but is altered in the context of neurodevelopmental disorders. In this regard, we use a model of human cerebral organoids (hCOs) to obtain a 3D environment faithful to human neurogenesis. These hCOs will be derived from induced pluripotent stem cells (hiPSCs) obtained from female patients with Rett syndrome carrying mutations in the MECP2 gene and isogenic control iPSC lines. We use a series of immunostaining, RT-qPCR and RNA sequencing experiments performed on these MECP2 mutant and control hCOs to help understand the significance of KCC2 cotransporter and other markers in Rett syndrome. With these experiments, we hope to provide further insight into the regulation of Cl- homeostasis in neurodevelopmental disorders. Specifically, studying the expression of the KCC2 in this pathological context will contribute to understanding the origin of the imbalance between excitatory and inhibitory activity in neurons.

Soumis par / Submitted by: Cabana, Jennifer

Affiliation: Centre de recherche CERVO

Résumé/Abstract #30

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Mechanoreceptors as Sound Translators: Tactile Perception of Complex Acoustic Vibrations

CHAUVETTE, LOONAN
Sharp, Andréanne

Introduction: This pilot study explores the capacity of skin mechanoreceptors to decode spectro-temporal characteristics of complex vibrations. While the auditory system adeptly decodes complex acoustic waveforms, resulting in the perception of distinct auditory timbres, it remains unclear whether the tactile system can similarly analyze the spectral and temporal features of mechanical vibrations.
Methods: Twelve pilot participants with normal hearing and no musical experience were recruited. The study utilized stimuli from the timbre section of the Adaptive Music Perception test, presented in both auditory (via circumaural headphones) and tactile (using the Multi-Channel Vibrotactile Glove, a patent-pending sensory substitution technology from our lab) modalities. Discrimination thresholds were obtained for the three principal spectro-temporal features associated with auditory timbre perception: attack time, spectral centroid, and spectral irregularity (even-to-odds harmonic ratio).
Results: While discrimination thresholds for attack time were comparable across modalities, thresholds for spectral features (spectral centroid, spectral irregularity) were higher in the tactile modality. Nonetheless, participants could discriminate complex mechanical vibrations based solely on these spectral features. Post-hoc correlation analyses also suggest associations between the performance across both modalities for attack time and spectral centroid, but not for spectral irregularity.
Conclusions: Our pilot study suggests that the tactile modality is able of discriminating complex vibrations using spectro-temporal features, albeit less efficiently than the auditory system. The observed correlation in performance across modalities hints at shared neural mechanisms underlying complex wave perception in both auditory and tactile domains. These results pave the way for further research into auditory-tactile integration and the development of innovative sensory substitution technologies for people with hearing impairments, musicians, and other groups who could benefit from enhanced perception.

Soumis par / Submitted by: Chauvette, Loonan

Affiliation: Centre de recherche CERVO

Résumé/Abstract #31

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Genetic identification of different populations of reticulospinal neurons of the medullary reticular formation: Neuroanatomical study

Abigail CHUBWA NDIKU, Narges KARIMI, Josée SEIGNEUR, Frédéric BRETZNER

OBJECTIVE
Through their projection into the spinal cord, reticulospinal neurons of the medullary reticular formation have direct access to the spinal locomotor circuitry involved in the control of motor movements and gait.
Recently, a subpopulation of neurons called V2a has been genetically identified by the expression of transcription factors Lhx3 and Chx10 during development. Functionally, these V2a neurons appear to be involved in turning during walking and in locomotor
arrest. While this subpopulation of V2a neurons in the medullary reticular formation is predominantly glutamatergic, we still do not know whether all glutamatergic reticulospinal neurons are V2a.
We hypothesized the existence of another class of non-V2a glutamatergic reticulospinal neurons in the medullary reticular formation.

METHOD

Three-week-old Chx10-CRE mice were injected into the lumbar segment of the spinal cord with two adeno-associated retrograde CRE-dependent viruses. Three weeks after injection, the mice were perfused and dissected. Neuronal tissues were frozen and cut using a cryostat. The extent of the virus injection site was confirmed in the spinal cord and the sections were imaged by epifluorescent microscopy. Expression of mcherry in the cytoplasm allowed us to identify glutamatergic cells expressing CamKIIα, a marker of glutamatergic neurons. Expression of green protein (GFP) in the nucleus of CamKIIα cells expressing Cre allowed us to identify V2a glutamatergic neurons, whereas expression of mcherry in the nucleus allowed us to identify no-V2a glutamatergic neurons. The topographical organization and colocalization of markers were analyzed using automated analysis software.
CONCLUSION
Our results identify for the first time the existence of V2a and no-V2a glutamatergic reticulospinal neurons in the medullary reticular formation that could contribute in different ways in motor and locomotor control.

Soumis par / Submitted by: CHUBWA NDIKU, ABIGAIL

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #32

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Simultaneous fluorophore discrimination and resolution improvement of super-resolution images using fluorescence lifetime

DESCHÊNES, ANDRÉANNE 1, Séverin Ollier, Antoine 1,2,3, Lafontaine, Marie 1,3, Michaud-Gagnon, Albert 1,2,3, De Koninck, Paul 1,4, Gagné, Christian 2,3, Lavoie-Cardinal, Flavie 1,3,5
1.Centre de recherche CERVO
2.Département de génie électrique et génie informatique, Université Laval
3.Institut intelligence et données, Université Laval
4.Département de biochimie, microbiologie et bio-informatique, Université Laval
5.Département de psychiatrie et neurosciences, Université Laval

To study the interactions between neuronal proteins with fluorescence microscopy, simultaneous observation of multiple biological markers is required. SPLIT-STED, an approach exploiting the analysis of fluorescence lifetime was developed to improve the spatial resolution of STimulated Emission Depletion microscopy. We developed an analysis approach using the law of linear combination of components in phasor space to multiplex SPLIT-STED and apply it to separate two spectrally indistinguishable fluorophores per imaging channel. We quantify and characterize the performance of our algorithm on simulated images constructed from real single-staining images.
This allows us to perform simultaneous resolution improvement and colocalization analysis of multiple protein species in live and fixed neuronal cultures. In fixed samples we imaged synaptic protein pairs and could visualize synaptic nanodomains. We also discriminate cytoskeletal proteins from synaptic proteins despite a large percentage of the images’ pixels containing mixtures of species. When applied to STED nanoscopy in living neurons, the multicolor SPLIT-STED approach allows the characterisation of neuronal protein organization at the nanoscale with reduced light exposure and photobleaching effects.
Multicolor SPLIT-STED opens the door to future experiments studying dynamic neuronal protein interactions at the nanoscale.

Soumis par / Submitted by: Deschênes, Andréanne

Affiliation: Centre de recherche CERVO

Résumé/Abstract #33

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Microglia and neurons in the developing neonatal mouse cortex show distinct transcriptional and translational signals following lipopolysaccharide immune challenge

GADAGKAR SHRUTI, Boutej H., Weng Y., Martino E., Vexlar ZS, Kriz Jasna

Neonatal mouse brain is very dynamic, with microglia actively phagocytizing overproduced neurons and weak synapses. An immunological insult can lead to aberrant microglial response, ultimately damaging the neurons and potentially leading to neurological disorders. While many studies have been focusing on the identification and description of context-dependent microglia immune transcripts, in vivo microglial and neuronal proteomics and associated regulatory mechanisms in neonates are less well defined. One of the limiting factors is lack of appropriate animal models to study real-time in vivo transcriptional and translational dynamics.
To decipher the microglial-neuronal molecular communication in vivo, we created a transgenic model developed in our lab: the NFLrRFPxCD11brGFP mouse line, where the ribosomes of microglia are labelled with GFP and FLAG and of neurons with RFP. We performed a systemic lipopolysaccharide injection on post-natal day (P) 9 to stimulate immune response and analysed on P10. Using modified translational ribosome affinity purification, we took a snapshot of the dynamic translational state of microglial and neuronal ribosomes by capturing the real-time transcribed mRNAs and translated peptides. We identified the top mRNA and protein signatures associated with microglial and neuronal action. Interestingly, we found that the top upregulated microglial and neuronal transcripts were not translated. The microglial mRNA signatures suggest an inflammatory profile, but the peptidyl profile gravitates towards homeostasis. We verified our findings by performing western blot on microglia and neurons which were isolated using CD11b beads and the neuronal isolation kit (Miltenyi Biotec®). Additionally, our results from microglial cytokine array indicate no distinct differences between the expression of inflammatory cytokines between male and female neonatal mice.
Collectively our results indicate discrepancy in the mRNA and the peptidyl profiles of microglia and neurons in neonatal mice. This possibly hints at the existence of a post-transcriptional regulation. Targeting such regulators may normalize the immune profile by aiding microglial phagocytosis and ultimately bringing homeostasis, thus paving a way to novel therapeutic targets.

Soumis par / Submitted by: Gadagkar, Shruti

Affiliation: Centre de recherche CERVO

Résumé/Abstract #34

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Synaptic alterations of neuronal outputs from the lateral habenula in the model of chronic social defeat

HERNANDEZ SILVA, JOSE CESAR, Pausic ,Nikola and Proulx ,Christophe
CERVO research center

The lateral habenula, the main disappointment center of the brain, has been shown to be hyperactive in depressive disorders. However, how synaptic transmission at its neural outputs is affected in depression is not known. Here, we use optogenetics and electrophysiology to examine synaptic transmission from the LHb to three of its main output targets: the serotoninergic dorsal raphe nucleus (DRN), the rostromedial tegmental nucleus (RMTg), and the ventral tegmental area (VTA), in mice subjected to chronic social defeat stress (CSDS). To activate LHb efferents, an AAV-ChR2-mCherry is first injected in the LHb. Ten days later, mice are subjected to 10 days of CSDS, and tested in the social interaction test to determine their resilience or susceptibility to chronic defeat stress. Acute brain slices are obtained from control, susceptible and resilient mice and synaptic transmission is examined using whole-cell patch clamp recordings. At the LHb-DRN synapses, chronic stress did not change paired-pulse ratio (PPR) but increased the evoked AMPAr/NMDAr ratio in susceptible mice. At the LHb-RMTg synapses, CSDS decreased paired-pulse ratio both in susceptible and resilient mice while decreasing evoked AMPAr/NMDAr ratio in resilient mice. Finally, at the LHb-VTA synapses, CSDS decreased AMPAr/NMDAr ratio in susceptible mice while no change was observed for PPR. Also, we found a decreased intrinsic activity in VTA projecting LHb neurons and an imbalance in the excitatory-inhibitory inputs to the VTA- and RMTg-projecting LHb neurons Taken together, these results suggest that LHb neural outputs are differently altered following CSDS, and these synaptic changes may contribute to distinct symptoms found in depressive disorders.

Soumis par / Submitted by: Hernandez Silva, Jose Cesar

Affiliation: Centre de recherche CERVO

Résumé/Abstract #35

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

The role of lateral habenula transmission to dopamine center in associative learning and defensive behaviors

IHIDOYPE, MARINA; Hernández Silva, José César; Vambre, Claire; Derwel, Cléo; Pellerin, Kelly-Ann; Martianova, Ekaterina; Maryse, Pinel; Proulx, Christophe

Adapting behavioral responses to threats is crucial for survival. The lateral habenula (LHb) receives neural inputs from the basal ganglia and limbic system, and in turn sends neural projections to the dopaminergic ventral tegmental area (VTA). In this project, we test the hypothesis that VTA-projecting LHb neurons encode aversive signals involved in associative learning to promote escape behavior. Specifically, using an intersectional viral approach to drive expression of GCaMP6s in VTA-projecting neurons, we found that an auditory cue (tone) paired with a foot shock progressively causes cue-driven activity in VTA-projecting LHb neurons during an avoidance learning task (paired group), which is not observed when the tone is not contingent to a foot shock (unpaired). We also found that activity at VTA-projecting LHb neurons increases when mice initiate avoidance responses in the avoidance learning task, as well as at movement onset in the tail suspension test (TST). Blocking transmission at VTA-projecting LHb using the tetanus light chain (TeLC) is sufficient to reduce avoidance learning, and to reduce movement in the TST. Finally, optogenetically assisted whole cell electrophysiology recordings revealed synaptic adaptations at LHb terminals synapsing onto dopamine neurons (TH+) after a single avoidance learning session, yet onto TH- neurons after three sessions of avoidance learning (expert mice). Together, these results support the importance of the LHb-VTA pathway contribution for cue-outcome association and to engage defensive responses in aversive contexts.

Soumis par / Submitted by: Ihidoype, Marina

Affiliation: Centre de recherche CERVO

Résumé/Abstract #36

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Input-specific coordination of superficial and deep CA1 pyramidal cells by VIP interneurons

ILOUN PARISA 1,2, Ahadi Mehran 2,3, Veillette Felix 1,2, Topolnik Dimitry 2, Skinner Frances 4,5, Topolnik Lisa 1,2

1 Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, QC, Canada
2 Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, QC, Canada
3 Department of Electrical and Computer Engineering, Laval University, Québec, QC, Canada
4 Krembil Research Institute, University Health Network, Toronto, ON, Canada
5 Department of Physiology, University of Toronto, Toronto, ON, Canada

Pyramidal cells (PCs) in the hippocampal CA1 area are categorized into superficial (sPCs) and deep (dPCs) types based on their position along the hippocampal radial axis and distinctive morpho-functional properties. Notably, these PC types display specific connectivity patterns with parvalbumin-expressing interneurons. However, whether they exhibit different connections with other interneuron types in CA1 remains unclear. Vasoactive intestinal polypeptide-expresing (VIP) interneurons (VIP-INs) consist of two primary types: cholecystokinin-coexpressing basket cells (VIP-BCs) and interneuron-selective (VIP-IS) cells. VIP-BCs inhibit PCs, while VIP-IS cells disinhibit PCs by suppressing interneurons. The coordination of dPC and sPC activity by distinct types of VIP-INs remains unexplored. Here, we found that while VIP-INs provide inhibition to both PC types, the integration of excitatory inputs from the temporoammonic (TA) and Schaffer collateral (SC) pathways by PCs is primarily orchestrated through VIP-IS-mediated disinhibition. Specifically, upon TA pathway activation, both dPCs and sPCs exhibited increased inhibitory postsynaptic responses (IPSPs) following chemogenetic silencing of VIP-INs. Similar VIP-IS-mediated disinhibition was revealed in both PCs types by driving selectively the lateral enthorhinal cortex input. However, during SC pathway activation, only dPCs displayed increased IPSPs upon VIP-IN silencing, revealing sublayer-specific disinhibition. In turn, sPCs showed higher excitatory responses from the SC pathway upon VIP-IN silencing, consistent with the shunting inhibitory effect of VIP-INs. Furthermore, chemogenetic silencing of VIP-INs in awake animals resulted in reduced power for mid-frequency gamma oscillations conveyed by the TA pathway but increased theta phase modulation for low-frequency gamma oscillations carried by CA3. These findings indicate that VIP-INs in the CA1 region participate in both inhibitory and disinhibitory circuit motifs. They facilitate the integration of the TA pathway into both sPCs and dPCs but promote the recruitment of dPCs via the SC input, establishing a temporal framework for input-specific PC spike timing and modulating hippocampal rhythmic activities during spatial learning.

Soumis par / Submitted by: Iloun, Parisa

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #37

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Functional investigation of glutamatergic neurons of medullary reticular formation nuclei in locomotor recovery after spinal cord injury

KARIMI, NARGES; Lemieux,Maxime; Bretzner,Frederic
Centre de recherche du CHU de Québec, Université Laval, Québec, Canada

The medullary reticular formation (mRF) is an extensive part of the brainstem controlling variety of motor and locomotor functions. Although anatomical studies have shown plasticity of reticulospinal axons or neurons after spinal cord injury (SCI), little is known about their neurotransmitter phenotype and their functional contribution to locomotor recovery. Using kinematic and electromyographic measurements in transgenic mice, we investigated changes in locomotor functions upon photostimulation of glutamatergic neurons of different mRF nuclei. Before SCI, long trains of photostimulation for 1 s led to different locomotor behaviors including initiation, acceleration, pause, or locomotor arrest depending on the stimulation site within the mRF. Seven weeks after SCI, some of these sites kept their functional effects, whereas others exhibited plasticity with the emergence of new functions. Furthermore, in chronically impaired mice, long trains of photostimulation reduced the variability in locomotor stepping and normalized to pre-injury levels the position of the ankle prior to the swing phase, thus improving locomotion. In summary, our findings show that glutamatergic neurons of the mRF contribute to locomotor recovery after SCI and can improve functional outcome after chronic SCI.

Funding: Craig H. Neilsen Foundation and Wings for Life Foundation

Soumis par / Submitted by: Karimi, Narges

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #38

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Découverte de la micro-circuitrie du cerveau par l’approche de traçage trans-synaptique

Yahia Karioun1, Charles Gora1, Nizar Chetoui1, Modesto Peralta1, Vincent Breton-Provencher1,2, Marie-Eve Paquet1, and Martin Lévesque1,2.
1 Centre de Recherche CERVO (2601 Chemin de la Canardière,
Québec, QC, G1J 2G3, Canada)
2 Département de psychiatrie et de neuroscience, Université Laval,
Québec, QC, Canada

Les neurones dopaminergiques (DA) du mésencéphale sont la principale source de dopamine dans le cerveau. Ces neurones ne sont pas homogènes et possèdent des profils génétiques et projections axonales distincts. La dopamine libérée par les
neurones DA se lie à des récepteurs DA qui existent principalement sous deux formes: ceux de type D1 et ceux de type D2. En se liant aux D1 ou D2, la dopamine exerce des effets opposés, respectivement excitateurs ou inhibiteurs. Le striatum est la structure qui reçoit la majorité de la dopamine. L’identification récente de sous-types de neurones dopaminergiques nous mène à poser l’hypothèse que certains d’entre eux cibleraient spécifiquement des neurones striataux exprimant les récepteurs D1 ou D2.

Pour vérifier notre hypothèse, nous avons développé une approche de marquage neuronal utilisant des vecteurs viraux trans-synaptiques afin de visualiser les sous-circuits cérébraux. Pour visualiser les neurones faisant synapse avec ceux possédant
les récepteurs D1 ou D2, nous utilisons de souris transgéniques dont les neurones expriment les recombinases Cre (D1) et Flip (D2). À l’aide de vecteurs AAV dépendants de Cre ou de Flip, nous forçons l’expression d’un récepteur permettant l’entrée d’un
second vecteur viral Rabique trans-synaptique. Cette approche nous permet de marquer sélectivement avec des protéines fluorescentes distinctes, tous les neurones établissant des synapses avec ceux exprimant D1 ou D2. Afin de caractériser les neurones DA ciblant soit les neurones D1 ou D2, nous utilisons des techniques de co-marquage immunohistochimique à l’aide d’anticorps spécifiques à un sous-type de neurones dopaminergiques.

Nos résultats préliminaires confirment le fonctionnement et la validité de notre approche expérimentale. De plus, nos données suggèrent qu’il existe des neurones dopaminergiques qui établissent des synapses spécifiquement avec les neurones striataux exprimant uniquement les récepteurs D1 ou D2.

En conclusion, la réalisation de ce projet nous permettra d’établir une cartographie précise de l’organisation des sous-circuits dopaminergiques et de mieux comprendre le rôle de la dopamine. De plus, notre modèle pourrait être appliqué à d’autres régions
cérébrales pour mieux caractériser les sous-circuits du cerveau qui demeurent encore inconnus

Soumis par / Submitted by: Karioun, Yahia

Affiliation: Centre de recherche CERVO

Résumé/Abstract #39

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Structural and genetic constraints on zebrafish brain networks

– LÉGARÉ, ANTOINE
Département de biochimie, de microbiologie et de bio-informatique
– Boily, Vincent
Centre de Recherche CERVO
– Poulin, Sandrine
Département de biochimie, microbiologie et bio-informatique
– Légaré, Arthur
Département de physique, génie physique et optique
– Poulin, Hugo
Centre de recherche CERVO
– Lemieux, Mado
Centre de recherche CERVO
– Desrosiers, Patrick
Centre de recherche CERVO, Département de physique, génie physique et optique
– De Koninck, Paul
Centre de recherche CERVO, Département de physique, génie physique et optique

Network science has greatly enhanced our understanding of the large-scale organization of nervous systems, despite the absence of detailed cellular information in numerous studies. Leveraging advances in optical imaging and genetically encoded sensors, we performed whole-brain imaging at cellular resolution in zebrafish larvae to investigate mesoscopic functional connectivity (FC). We recorded neuronal activity from approximately 50000 cells in head-restrained transgenic larvae, expressing GCaMP6s in every neuron, while simultaneously monitoring tail movements. We computed mesoscopic FC from regional calcium signals, revealing similar functional network architecture across larvae. Remarkably, FC fingerprinting allowed the identification of subjects over separate imaging sessions, demonstrating the reproducibility of these measurements. To probe the structure-function relationship of zebrafish brain networks, we generated a mesoscopic wiring diagram using a dataset of over 4000 neuron reconstructions. We found a strong correlation between structural connectivity (SC) and FC, with several structural network properties such as the shortest polysynaptic paths between two regions predicting over half the variance of FC. Next, we identified structural network communities, which overlapped significantly with brief regional coactivation patterns observed in multiple animals. Some of these activity patterns emerged spontaneously, while others were robustly elicited by visual stimuli. We identified stimulus- and motor-correlated cells to generate anatomical maps of functionally specialized populations, which segregated along the rostrocaudal axis of the brain. Interestingly, this “sensorimotor axis” could be recovered from a diffusion gradient derived independently from both spontaneous FC and SC matrices, suggesting that functional specialization can be inferred from network topology. Finally, we used spatially resolved gene markers to identify a subset of genes whose co-expression significantly predicted regional FC. Our results highlight several key principles by which functional connectivity is shaped by structural and genetic constraints, setting the stage for future investigations into the developmental trajectories of brain networks and their deviations in disease.

Soumis par / Submitted by: Légaré, Antoine

Affiliation: Centre de recherche CERVO

Résumé/Abstract #40

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Acute effect of optogenetic VTA stimulation on the neural dynamics of M1

Aoxue Miao, Vincent Savard, Christian Ethier

The primary motor cortex (M1) plays a crucial role in the precise control of voluntary movements and the acquisition of new motor skills. Past research has shown the presence of dopamine (DA) innervation in the M1 of both rats and monkeys, suggesting a direct modulation of neuronal activity. However, the exact role of the ventral tegmental area (VTA), which is the origin of DA neurons, remains unknown. In this study, we demonstrated the acute effect of VTA stimulation on M1 neural activity using optogenetics and electrophysiological recordings. We observed single-neuron response to VTA stimulation and unveiled the influence of VTA stimulation on M1 neural activity. These results indicate that VTA has a direct effect on M1 and suggests a potential contribution to fine forelimb movement and influence motor learning and plasticity.

Soumis par / Submitted by: Miao, Aoxue

Affiliation: Centre de recherche CERVO

Résumé/Abstract #41

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Développement d’une approche multimodale pour suivre le transit des vecteurs viraux de type AAV à l’intérieur des cellules

PAQUET, LAURENCE(1, 2); Echanove, Jose(1); Méroné, Jaëlle(1,3); Barbeau, Annie(1); Dalangin, Rochelin(1); Godin, Antoine G(1,4); Paquet, Marie-Eve(1,2)

1 – Centre de recherche CERVO
2 – Département de biochimie, microbiologie et bio-informatique, Université Laval
3 – Département de médecine, Université Laval;
4 – Département de psychiatrie et neurosciences, Université Laval;

Les virus adéno-associés recombinants (rAAV) font partie des véhicules de choix pour le transport d’outils optogénétiques à l’intérieur des cellules. Ceux-ci permettent l’infection spécifique d’une grande variété de cellules telles que les neurones. Cependant, bien que les rAAV contribuent à l’observation d’une panoplie de mécanismes biologiques in vivo, leur transduction est un phénomène qui demeure très complexe. Mon projet de maitrise consiste donc à développer une approche multimodale pour suivre le transit des vecteurs viraux de type AAV à l’intérieur des cellules, plus particulièrement des neurones, en temps réel. Mon projet est divisé en trois objectifs principaux : le marquage des capsides d’AAV, le marquage de sous-compartiments cellulaires et l’utilisation de la microscopie à fluorescence pour suivre en temps réel l’infection d’un rAAV. Cette stratégie permettra de mieux comprendre le processus infectieux des AAV et contribuera à leur utilisation en tant que vecteurs viraux.

Soumis par / Submitted by: Paquet, Laurence

Affiliation: Centre de recherche CERVO

Résumé/Abstract #42

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Lateral hypothalamus controls serotonin neurons through disinhibition mechanism

SADRETDINOVA RENATA, Benmammar Zakaria, Proulx Christophe D.
CERVO Brain Research Center

Lateral hypothalamic area (LHA) regulates crucial behavioural aspects such as energy balance, wakefulness, and motivation. Recently, it was shown that LHA signalling onto the serotonergic dorsal raphe nucleus (DRN) encodes the initiation of locomotion. However, the precise neural circuitry involved is not yet characterized.
In the current study, we investigated the anatomical and functional reciprocal circuitry between the LHA and the DRN. Specifically, using anterograde (AAV1-hSyn-cre-WPRE) and retrograde viral (AAV2/retro-CAG-Flpo) tools, we targeted DRN cells receiving input from the LHA (DRN input) and DRN cells projecting onto the LHA (DRN output), respectively.
Our results show that DRN input and DRN output neurons are largely two distinct neuronal populations with a differential spatial distribution. The LHA makes synaptic contact with both 5-HT and non-5-HT neurons in the DRN; however, there were significantly more non-5HT cells labeled. Interestingly, input 5-HT and non-5-HT neurons were located with a spatial bias toward the ventromedial part and dorsolateral parts of the DRN, respectively. To identify the projection areas of targeted input and output neurons, we conducted whole-brain axon tracing, revealing that the main projection areas for both cell populations were subcortical and largely overlapping. Next, we asked whether the input cells synapse locally onto other DRN neurons. Optostimulation of DRN input cells induces convergent excitatory and inhibitory postsynaptic currents in local DRN cells, with a predominating inhibitory component. Chronically inhibiting the input cells’ activity by expressing the light chain of tetanus toxin (TeLC) led to increased mobility and higher locomotion speed in TeLC-expressing mice compared to the control group.
Overall, these results demonstrate that the lateral hypothalamus primarily regulates the dorsal raphe nucleus (DRN) by inhibiting local GABAergic neurons, ultimately resulting in the disinhibition of 5-HT neurons.

Soumis par / Submitted by: Sadretdinova, Renata

Affiliation: Centre de recherche CERVO

Résumé/Abstract #43

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Effect of VTA stimulation on motor recovery after stroke

SEN, DEEPSHIKHA
Vaziri, Zohreh
Borelli, Megan
Sedghi, Shiva
Éthier , Christian
Centre de Recherche CERVO, Université Laval

Loss of motor function is one of the major physical challenges faced by patients recovering from stroke. Motor skills can be learned (or re-learned after a stroke) through practice and repetition. Dopamine (DA), a neurotransmitter typically associated with rewards, pleasure, and addiction, could also play a critical role in motor skill learning and synaptic plasticity in the motor cortex. The motor cortex receives dopaminergic inputs corresponding to motor skill learning from the Ventral Tegmental Area (VTA). DA reinforcement learning signal is suspected to play a critical role in the establishment of spike-timing-dependent plasticity. During re-learning of motor skills after a stroke, the dopamine signals could guide synaptic plasticity and reshape neural circuits, leading to efficient motor recovery.

We hypothesize that the VTA DA fibers innervating the motor cortex carry a reinforcement learning signal that guides motor recovery after stroke.

We utilized a rat model of stroke and forelimb motor recovery. We used Endothelin-1 or Photothrombosis to create a cortical lesion in the Caudal Forelimb Area (CFA), the main region dedicated to forelimb motor control. We employed specifically timed optogenetic manipulations for stimulating the VTA neurons. We injected AAV2/8-CaMKIIa-ChRmine-mScarlet into the VTA, leading to the expression of ChRmine in VTA neurons. ChRmine is a light-sensitive opsin that can be activated by a suitable wavelength of light.

We used the Montoya staircase and Cylinder tasks to assess forelimb motor deficits before and after the stroke. We used the Knob rotation supination task to assess fine forelimb activity and for motor rehabilitation after stroke. During rehabilitation, VTA neurons were stimulated following a good forelimb movement.

Rats showed higher motor deficits following a cortical and striatal stroke using Endothelin-1 as opposed to a cortical stroke using Photothrombosis. VTA stimulation during a rehabilitation task after a stroke seems to affect motor performance in the supination task. However, its effect on improving motor recovery needs to be studied with a greater number of animals. In addition, better rehabilitation tasks for forelimb recovery need to be explored.

Soumis par / Submitted by: Sen, Deepshikha

Affiliation: Centre de recherche CERVO

Résumé/Abstract #44

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Hippocampal CA1 VIP interneurons detect novelty in the environment and support recognition memory

TAMBOLI SUHEL 1,2, Sanjay Singh 1,2,Dimitry Topolnik 1,2, Alexandre Guet-McCreight 3, Lisa Topolnik 1,2
1 Neuroscience Axis, CRCHUQ-CHUL; 2 Dept. of Biochemistry, Microbiology and Bioinformatics, Université Laval;
3 Krembil Centre for Neuroinformatic, University of Toronto

In the CA1 hippocampus, vasoactive intestinal polypeptide-expressing interneurons
(VIP-INs) play a prominent role in disinhibitory circuit motifs. However, the specific
behavioral conditions that lead to circuit disinhibition remain uncertain. To investigate
the behavioral relevance of VIP-IN activity, we employed wireless technologies
allowing us to monitor and manipulate their function in freely behaving mice. Our findings
reveal that during spatial exploration in new environments, VIP-INs in the CA1
hippocampal region become highly active, facilitating the rapid encoding of novel
spatial information. Remarkably, both VIP-INs and pyramidal neurons (PNs) exhibit
increased activity when encountering novel changes in the environment, including
context- and object-related alterations. Concurrently, somatostatin- and parvalbumin-expressing
inhibitory populations show an inverse relationship with VIP-IN and PN
activity, revealing circuit disinhibition that occurs on a timescale of seconds. Thus, VIPIN-
mediated disinhibition may constitute a crucial element in the rapid encoding of
novelty and the acquisition of recognition memory.

Soumis par / Submitted by: Tamboli, Suhel

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #45

Axe de recherche / Research Axis: 3. Circuitrie et plasticité / Circuitry and plasticity

Spatially resolved expression of noradrenergic receptor transcripts in cortical neurons

EMMERAUDE TANGUAY 1,2 , Paul De Koninck 1,2, Vincent Breton Provencher 1,2
1Ctr. De Recherche Univ. Laval Cervo, Quebec, QC, Canada;
2Univ. Laval, Québec, QC, Canada

The noradrenergic system plays a critical role in learning by influencing cortical activity through a dense network of noradrenergic axons and their interactions with diverse receptors. However, the mechanisms by which noradrenaline modulates the distinct cellular components of cortical circuits remain poorly characterized. Here, our objective is to map the expression of each subtype of noradrenergic receptors – α-1(a,b,d), α-2(a,b,c), and β-(1,2,3) – onto the subclasses of cortical interneurons. To achieve this, we analyzed the RNA expression of noradrenergic receptor subtypes using a transcriptomic cell-type atlas of the mouse and human motor cortex. Our findings revealed robust expression of α-1a, α-1b, α-2a, α-2c, and β-1 receptor transcripts in the cortex. In addition, α-1 receptor transcripts showed peak expression in inhibitory neurons, while glutamatergic neurons primarily expressed β receptor transcripts. To investigate the spatial distribution of these expression patterns within cortical microcircuits, we used fluorescence in situ hybridization to label the RNA of noradrenergic receptors alongside the main subclasses of GABAergic interneurons: Vip-, Sst-, Pval-, and Ndnf-expressing cells. To automate region annotation and fluorescence quantification, we developed a pipeline to detect somas and register their position to a reference atlas. Our preliminary results showed a difference in the expression of α-1 receptor transcripts across cortical layers in Vip+ and Sst+ cells, suggesting that the influence of noradrenaline release is layer-specific for these subclasses of interneurons. We are currently extending those analyses to include other noradrenergic receptors and explore regional differences in noradrenergic receptor expression. Future experiments will evaluate how the expression of noradrenergic receptors affects interneuron activity during the learning of a sensorimotor task. Thus far, our results suggest that noradrenaline modulates cortical circuits by differentially targeting GABAergic cortical interneurons based on their subclass and position within the cortex. These findings represent an important step toward our goal of understanding the mechanisms through which noradrenaline shapes cortical circuits at various stages of learning.

Soumis par / Submitted by: Tanguay, Emmeraude

Affiliation: Centre de recherche CERVO

Résumé/Abstract #46

Axe de recherche / Research Axis: 2. Douleur et contrôle sensorimoteur / Pain and sensorimotor control

Cohérence corticomusculaire dans l’exécution d’une tâche volontaire et posturale

FAKHRY NADIM, Rabiei Pouya, Simoneau Martin, Massé-Alarie Hugo

Les muscles du dos remplissent différentes fonctions, telles que le contrôle postural (par exemple, ajustements posturaux lors de mouvements des membres) et le contrôle volontaire (par exemple, l’extension de la colonne vertébrale), impliquant différents circuits neuronaux. Par contre, on connait encore mal les différents circuits qui sont impliqués dans le contrôle de chacune de ces tâches. La cohérence cortico-musculaire (CMC) est une technique qui combine les signaux d’EEG (électroencéphalographie) – mesurant l’activité corticale – et d’électromyographie (EMG) – mesurant l’activité musculaire- pour déterminer leur synchronisation (i.e. corrélation entre les signaux) dans des bandes de fréquences sélectionnées. Il est suggéré que cette synchronisation représente l’importance de la connectivité entre des régions spécifiques du cortex moteur et un groupe musculaire donné. L’objectif principal de cette étude est de mesurer et comparer la CMC des muscles du dos lors de tâches volontaires et posturales activant les muscles du dos (érecteurs du rachis lombaire). Vingt participants seront recrutés et réaliseront une tâche de temps de réaction simple. Des lumières s’allumeront successivement et indiqueront au participant de se préparer puis de réaliser la tâche le plus rapidement possible. Le participant devra maintenir la contraction 5 secondes. Cinquante essais par tâche seront réalisés. Ce projet comprend deux tâches principales : une tâche volontaire (bascule du bassin), et une tâche posturale (flexion rapide des épaules produisant des ajustements posturaux). L’analyse de la CMC sera effectuée en utilisant des enregistrements électrophysiologiques combinant l’EEG pour les signaux corticaux et l’EMG pour les signaux musculaires des muscles érecteurs du rachis lombaires.

Soumis par / Submitted by: Fakhry, Nadim

Affiliation: CIRRIS

Résumé/Abstract #47

Axe de recherche / Research Axis: 2. Douleur et contrôle sensorimoteur / Pain and sensorimotor control

Réparation de nerfs périphériques par génie tissulaire chez un modèle de lapin

OUMAYMA HAYOUNI
Alexane Thibodeau
Todd Galbraith
Hélène khuong
François Berthod
Faculté de la médecine, département de la chirurgie
Laboratoire d’organogénèse expérimentale (LOEX)

Les lésions nerveuses peuvent conduire à une perte de sensibilité tactile et une paralysie complète. L’autogreffe nerveuse, le standard en clinique, induit un déficit au site de prélèvement en plus d’une récupération fonctionnelle incomplète. L’alternative est d’utiliser des conduits nerveux faits de biomatériaux pour guider la migration axonale, mais ceux-ci comportent plusieurs limites cliniques. Objectif Notre objectif est de fabriquer un tube nerveux (TN) vivant complètement autologue dans lequel un réseau de capillaires sera développé in vitro par ensemencement de cellules endothéliales (CE). Un tube nerveux contenant un réseau capillaire préétabli pouvant se connecter rapidement à la vascularisation de l’hôte est une option prometteuse pour réparer des lésions majeures (>3 cm). Méthodes Les TN sont constitués d’un feuillet de fibroblastes humains ensemencés avec des CE et enroulé pour former une structure tubulaire. Les TN ont été implantés chez des lapins néo-zélandais immunodéprimés pour réparer une lésion du nerf fibulaire de 4 cm avec un suivi de 36 semaines. La masse du muscle fibulaire est un bon indice de l’état de réinnervation. La conduction nerveuse du nerf fibulaire ainsi que l’activité musculaire par un électromyogramme ont été évaluée aux trois semaines. Le Toe Spread Index (TSI) permet de suivre le retour des fonctions motrices. Résultats Le groupe TN a récupéré une masse musculaire significativement plus importante que le contrôle non réparé (p<0,05). L'analyse de la conduction nerveuse dans le muscle tibialis anterior a montré que la récupération nerveuse avait débuté vers la 18e semaine. L'électromyogramme du muscle tibial montre une activité électrique au repos avec de multiples activités polyphasiques (une réinnervation en cours) vers la 24ème semaine. Après 36 semaines, une amélioration du TSI a montré une récupération partielle de la fonction motrice du groupe autogreffe (p<0,05), également observée dans le groupe TN, mais avec une tendance non significative. Conclusion La combinaison de l’électromyographie et l’étude de la conduction nerveuse couplé à un test de la fonction motrice permet une quantification précise de l'efficacité d'une greffe nerveuse chez le lapin. De plus, notre approche avec un TN autologue vivant pré-vascularisé pourrait être essentielle pour soutenir la migration axonale sur de longues distances et ainsi être un nouvel outil clinique prometteur pour réparer les lésions de grande taille.

Soumis par / Submitted by: Hayouni, Oumayma

Affiliation: CRCHU de Québec-UL, pavillon HEJ

Résumé/Abstract #48

Axe de recherche / Research Axis: 2. Douleur et contrôle sensorimoteur / Pain and sensorimotor control

Characterization of Pain-Associated Neurons in Chronic Inflammatory Diseases: A Study of Spatial Transcriptomic Profiling and Single-Cell RNA Sequencing.

ILLIANO CAMILLE (Axe Neurosciences du Centre de recherche du CHU de Québec–Université Laval et Département de médecine moléculaire de l’Université Laval, Québec, Canada), Vallières Nicolas (Axe Neurosciences du Centre de recherche du CHU de Québec–Université Laval et Département de médecine moléculaire de l’Université Laval, Québec, Canada), Texeraud Emeric (Axe Endocrinologie-néphrologie du Centre de recherche du CHU de Québec–Université Laval et Département de médecine moléculaire de l’Université Laval, Québec, Canada), Droit Arnaud (Axe Endocrinologie-néphrologie du Centre de recherche du CHU de Québec–Université Laval et Département de médecine moléculaire de l’Université Laval, Québec, Canada), Lacroix Steve (Axe Neurosciences du Centre de recherche du CHU de Québec–Université Laval et Département de médecine moléculaire de l’Université Laval, Québec, Canada)

We have previously demonstrated that knockout of the gene encoding the interleukin-1 receptor type 1 (IL-1R1) specifically in TRPV1+ sensory neurons of dorsal root ganglia (DRGs) prevents the perception of tactile pain (allodynia) in mice with chronic inflammatory diseases, without affecting the development of other clinical signs. Since only 5% of nociceptors express IL-1R1 and considering that Il1r1 mRNA expression may not directly equate with protein expression, we took advantage of NanoString technology, combining immunofluorescence microscopy with spatial RNA sequencing (spRNA-Seq), to characterize the gene expression profile of IL-1R1+ neurons. Using the GeoMx Whole Transcriptome Assay, we compared the transcriptome of HuC/HuD+ TRPV1+ IL-1R1+ neurons with that of other neuronal populations in DRGs. Bioinformatic analysis of spRNA-Seq data identified a transcriptomic signature specific to IL-1R1+ neurons: Ada, Cysltr2, Gm525, Gpr139, Htr1a, Htr1f, Il31ra, Nppb, Npy2r, Nts, P2rx2, Pde4c, and Sst. These results were further validated through a single-cell RNA sequencing (scRNA-Seq) analysis performed on neurons isolated from lumbar DRGs of adult C57BL/6 mice injected or not with IL-1β intra-cisterna magna 1, 4 or 24 hours prior to sacrifice. The scRNA-Seq data revealed that HuC/HuD+ TRPV1+ IL-1R1+ neurons correspond to the non-peptidergic and unmyelinated nociceptor population known as NP3, which is associated with inflammatory itching. Results from the expression analysis showed differentially expressed genes (DEGs) in the NP3 population 4 hours after IL-1β injection, while the transcriptomes of other DRG neuron subpopulations remained unchanged compared to sham mice and other time points. Notably, we identified upregulated genes associated with chronic inflammatory pain among these DEGs (Alkal2, Lcn2, Bdnf…). Our study has thus identified new specific markers for IL-1R1+ nociceptors and confirmed their involvement in inflammatory pain.

Soumis par / Submitted by: Illiano, Camille

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #49

Axe de recherche / Research Axis: 2. Douleur et contrôle sensorimoteur / Pain and sensorimotor control

The human balance control detection threshold does not obey Weber’s law during high-frequency body oscillations in young adults.

OMERANI ATIKA, Cyr Jean-Philippe, Mackrous Isabelle, Carriot Jérôme, Simoneau Martin.

CIRRIS, Québec, Canada.
Department of Physiology, McGill University, Québec, Canada.

Introduction: According to Weber’s law, the minimum difference that can be perceived between two stimuli increases linearly as a function of the amplitude of the initial stimulus. However, in monkeys, the detection threshold for vestibular afferents does not comply with Weber’s law. The threshold saturates as the angular velocity of the head increases. This saturation indicates an improvement in the detection of head velocities. The detection threshold for postural oscillations in humans has never been calculated. Studying this threshold would make it possible to identify people with an altered perception of body movements. Thus, this work aims to quantify the detection threshold (DT) of postural oscillations during electrical vestibular stimulations (EVS).

Method: We tested 15 people aged between 18 and 30. These people maintained a standing posture with their eyes closed. We measured head accelerations and ground forces using an accelerometer and a force platform. To induce postural oscillations, we used sinusoidal EVS with increasing amplitude (i.e., linear between 0 to 2 mA) and of 4 different frequencies: 0.1, 0.2, 0.5, and 1Hz. There were 15 trials of 60 seconds per frequency. We calculated participants’ DTs from the ratio of postural response gain to inter-trial variability.

Results: For the EVS conditions of 0.1 and 0.2 Hz, the DT increased linearly with the amplitude of the EVS, thus respecting Weber’s law. On the contrary, for EVS frequencies of 0.5 and 1 Hz, the DT did not increase proportionally with the amplitude of the EVS, it saturates when the amplitude of the EVS is approximately equal to 1.5 mA. This result indicates an improvement in the DT, which results from a saturation of the variability of the postural oscillations while the gain decreases. Thus, the mechanisms for detecting postural oscillations do not always obey Weber’s law. When the frequency of postural oscillations increases, our performance at detecting our oscillations is maintained. We suggest that improving the detection threshold contributes to the ability of the balance control system to perceive postural oscillations and maintain balance effectively even in challenging situations.

Soumis par / Submitted by: Omerani, Atika

Affiliation: CIRRIS

Résumé/Abstract #50

Axe de recherche / Research Axis: 2. Douleur et contrôle sensorimoteur / Pain and sensorimotor control

Improving decision aids to predict persistent low back pain via psychological and neurophysiological biomarkers: protocol for a longitudinal cohort study

RABIEI POUYA, Centre interdisciplinaire de recherche en réadaptation et integration sociale (Cirris), Université Laval, Quebec City, Canada.
Coll Michel-Pierre, Centre interdisciplinaire de recherche en réadaptation et integration sociale (Cirris), Université Laval, Quebec City, Canada.
Roy Jean-Sébastien, Centre interdisciplinaire de recherche en réadaptation et integration sociale (Cirris), Université Laval, Quebec City, Canada.
Carlesso Lisa, School of Rehabilitation Sciences, McMaster University, Hamilton, Ontario, Canada.
Léonard Guillaume, CIUSSS de l’Estrie-CHUS, Centre De Recherche Sur Le Vieillissement, Sherbrooke, Canada.
Dionne Clermont, Population Health and Optimal Health Practices Research Unit, Centre de recherche du CHU de Québec-Université Laval, Québec City, Québec, Canada.
Lacasse Anaïs, Department of Health Sciences, Université du Québec en Abitibi-Témiscamingue, Rouyn Noranda, Canada
Tittley Jean, Centre interdisciplinaire de recherche en réadaptation et integration sociale (Cirris), Université Laval, Quebec City, Canada.
Fakhri Nadim, Centre interdisciplinaire de recherche en réadaptation et integration sociale (Cirris), Université Laval, Quebec City, Canada.
Masse-Alarie Hugo, Centre interdisciplinaire de recherche en réadaptation et integration sociale (Cirris), Université Laval, Quebec City, Canada.

Chronic low back pain (LBP) significantly contributes to the global burden of years lived with disability. Despite the existence of various decision aids for assessing the risk of chronicity, their accuracy in predicting the progression to chronic LBP is limited. Therefore, a deeper understanding of the mechanisms driving the development of chronic LBP, and the identification of predictive biomarkers, are imperative to enhance clinical evaluations and prescribe targeted interventions aimed at preventing pain chronicity. This longitudinal cohort study is designed to improve the performance of a widely used decision aid to predict LBP prognosis by identifying psychological and neural biomarkers present during the non-chronic phase. This study will follow 120 individuals with non-chronic LBP over one year. Initial data collection will encompass online psychological surveys, assessing pain-related psychological factors, and in-person assessments of neural biomarkers, including quantitative sensory testing, corticomotor excitability, somatosensory evoked potentials, and peak alpha frequency, using methods of pain pressure threshold, temporal pain summation, transcranial magnetic stimulation, and electroencephalography. The study’s outcomes are pain-related disability and presence of the chronic LBP assessed during follow-ups at 3, 6, and 12 months. A multivariate logistic regression using a backward stepwise selection procedure will be used to test the predictability of chronic LBP development using selected candidate biomarkers. This study aims to reveal variations in psychological and neurophysiological profiles associated with chronic LBP development. Moreover, the findings of this study have the potential to reduce healthcare expenditure by enabling early identification and treatment of patients with high risk of chronicity and a long-term disability.

Soumis par / Submitted by: Rabiei, Pouya

Affiliation: CIRRIS

Résumé/Abstract #51

Axe de recherche / Research Axis: 2. Douleur et contrôle sensorimoteur / Pain and sensorimotor control

FUNCTIONAL CONTRIBUTION OF MIDBRAIN NUCLEI TO LOCOMOTOR RECOVERY AFTER SPINAL CORD INJURY

ROUSSEL MARIE, Lemieux Maxime, Bretzner Frédéric
Centre de Recherche du CHU de Québec-Université Laval

Electrical stimulation of the midbrain has been shown to improve locomotor recovery after spinal cord injury (SCI). Are part of this functional region: the cuneiform nucleus (CnF) and the pedunculopontine nucleus (PPN). We have recently shown that activation of glutamatergic CnF neurons initiates and accelerates locomotion, whereas glutamatergic and cholinergic PPN neurons decelerate and stop locomotion in the mouse. We hypothesized that these distinct neuronal populations contribute differently to locomotor recovery after SCI. Transgenic VGluT2-cre mice were injected with AAV to genetically ablate or photostimulate glutamatergic CnF or PPN neurons. Although mice dragged initially their ipsilesional hindlimb, they recovered locomotor functions by the 3rd week post-SCI. 7 weeks post-SCI, genetic ablation of VGluT2+CnF neurons deteriorated motor functions during walking and swimming, whereas ablation of VGlut2+PPN neurons mildly impaired swimming. Short photostimulations of VGluT2+CnF or PPN neurons evoked phase-dependent electromyographic (EMGs) responses in hindlimb muscles during locomotion. Responses decreased at week 1 post-SCI but recovered by week 4 with locomotor recovery. Furthermore, long trains of photostimulations of VGlut2+CnF neurons improved and accelerated the locomotor pattern and rhythm, whereas VGlut2+PPN neurons failed to improve locomotor functions. Although the PPN has been considered as a target in clinical settings, our study argues that glutamatergic neurons of the CnF will be a better neurological target to improve functional locomotor recovery in SCI patients.

Soumis par / Submitted by: Roussel, Marie

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #52

Axe de recherche / Research Axis: 2. Douleur et contrôle sensorimoteur / Pain and sensorimotor control

Chronic pain induced depression in a sex-specific fashion: Role of the Anterior Cingulate Cortex

VEDARTHAM SRINIVASAN, VANDANA SHREE 1,2; Gaikwad, Mithil 1,2; Waegert, Robin 1; Fillinger, Clementine 1; Leboulleux Quentin 1,2; Abdallah, Khaled 1; Willem, Noémie 1; Lutz, Pierre-Eric 1; Labonté, Benoit 1,2; Yalcin, Ipek 1
1. Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France.
2. CERVO Brain Research Centre, Université Laval, 2601 Chemin de la Canardière, Quebec, QC, G1J 2G3, Canada.

Chronic pain is strongly associated with the development of anxiety and depressive disorders and represents a major cause of deterioration in quality of life. In recent years, our team has played a pioneering role in modeling this comorbidity in male mice using the sciatic nerve cuffing model of chronic neuropathic pain. Using this model, the central role of the anterior cingulate cortex (ACC) was highlighted, as well as molecular alterations occurring in this structure. However, epidemiological studies evidenced that the incidence of major depressive disorder and chronic pain is nearly 2 times higher in women compared to men, making it critical to consider sex as an essential parameter for scientific studies in the field. Accordingly, we first aimed at exhaustively characterizing the anxiodepressive consequences of chronic neuropathic pain in female mice. Our results showed that female mice do not display anxiety-like behavior in the context of chronic pain while they show depressive-like behavior at similar time points of the pain pathology as male mice. Building upon these findings, we conducted RNA- and Enzymatic Methyl-sequencing analyses in the ACC to determine the transcriptomic alterations as well as epigenetic adaptations with a special focus on DNA-methylation in female and male mice showing chronic pain-induced depression (CPID). The results, currently undergoing bioinformatic analysis, will guide the selection of a target gene for manipulation in subsequent stages of the research. The final phase involves manipulating the chosen gene in naive animals and the pain/depression comorbidity model, aiming to unravel the molecular basis of mood regulation. Overall, this project aims to provide a comprehensive understanding of the ACC’s role in emotional processing, with potential implications for identifying novel therapeutic targets in the context of chronic neuropathic pain.

Soumis par / Submitted by: Vedartham Srinivasan, Vandana Shree

Affiliation: Centre de recherche CERVO

Résumé/Abstract #53

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

The role of blood-brain interactions in the development of Huntington’s disease-related neuropathology

ALVES MARTINS BORBA, FLAVIA NATALE., Aurélie de Rus Jacquet., Francesca Cicchetti.
Centre de Recherche du CHU de Québec – Université Laval, Québec, QC, Canada; Department de Psychiatry & Neurosciences, Université Laval, Québec, QC, Canada.

Huntington’s disease (HD) is a neurodegenerative disease caused by a genetic mutation that results in the production of a mutant form of the protein Huntingtin (mHTT). This mutated protein is prone to misfolding and aggregation, accumulating aggregates in the brain and other organs. The resulting damage to cells and tissues causes neural degeneration in the striatum and cerebral cortex with progressive motor, cognitive, and behavioral impairments. The mutant protein is found in cerebrospinal fluid, plasma, and extracellular matrix and can amplify the disease phenotype. Recent studies have demonstrated that young blood from healthy individuals can improve tissue regeneration and have beneficial effects on cognitive function in aged mice. Previous research investigated the effects of parabiosis, a surgical technique that unites the circulatory systems of two living organisms, in HD mice, and these effects suggest that blood components may be responsible for pro-health benefits. Therefore, we hypothesize that healthy plasma may provide protective factors that improve HD-related traits. The project aims to identify plasma factors that cross the blood-brain barrier (BBB) and mediate neuronal and vascular improvements observed in HD mice. We will investigate changes in plasma protein signatures across the lifespan and use in vitro HD models to understand the role of blood-brain interactions in the development of HD-related neuropathology. To identify the potential benefits of healthy plasma, we leverage 2D and 3D BBB models produced using human induced pluripotent stem cells (iPSC) produced from control donors and people with HD. We differentiate iPSCs into endothelial cells, astrocytes, and neurons, and our models are treated with plasma from healthy donors and HD patients, as well as recombinant protein candidates to verify the potential benefits of specific molecules. For this purpose, by immunofluorescence, we analyzed the effect of plasma treatment on neurons by neurite length, neuroinflammation by ELISA, and integrity of the BBB. We also label plasma proteins with biotin to identify whether plasma proteins are taken up by cells and can possibly cross the BBB. Our preliminary data suggest that different plasma concentrations have different effects on the BBB, and the recombinant alpha-klotho protein has shown a potential benefit for improving neuronal health. We have also confirmed that biotinylated plasma proteins can be internalized by our cell types of interest. In conclusion, this project has the potential to shed light on novel mechanisms of blood-brain interactions in health and disease.

Soumis par / Submitted by: Alves Martins Borba, Flávia Natale

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #54

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Déterminer comment la protéine LRRK2 est impliquée dans la communication entre les astrocytes et les microglies dans la maladie de Parkinson

Océane Arevalo, Arnaud Droit, Eric Boilard, Aurélie de Rus Jacquet

INTRODUCTION. Les modes d’interactions entre les cellules gliales dans le processus de neurodégénérescence restent encore peu connus. La communication cellulaire peut s’effectuer par le biais de vésicules extracellulaires (VEs) produites naturellement tout au long de la vie d’une cellule. L’apparition de la maladie de Parkinson (MP) peut être liée à des facteurs génétiques, tel que la mutation G2019S de la protéine leucine-rich repeat kinase 2 (LRRK2). Chez l’humain, la protéine LRRK2 est abondante dans les cellules immunitaires et intervient dans de multiples processus, et notamment dans la régulation des procédés inflammatoires, où celle-ci prendra une forme de kinase hyperactive. Nous émettons l’hypothèse que la protéine LRRK2 joue un rôle de médiateur de la communication immunitaire microglie-astrocyte et, ainsi, réduire la fonction kinase de cette protéine pourrait réguler la neuro-inflammation. Cette étude a pour objectif de comprendre les interactions entre cellules gliales, notamment entre les astrocytes et les microglies au cours du développement de la MP. MÉTHODE. Pour ce faire, des astrocytes humains différenciés à partir de cellules souches pluripotentes induites (iPSCs) issues de donneurs sains ou de patients MP-LRRK2 G2019S vont être exposés à des cytokines microgliales pro-inflammatoires. Afin de définir l’implication de la fonction kinase de LRRK2, celle-ci sera désactivée par des traitements avec un inhibiteur. Après traitement, les VEs du milieu conditionné d’astrocytes seront analysés par cytométrie en flux ainsi que par protéomique et la quantité de cytokines pro-inflammatoires sécrétée par les astrocytes sera déterminée par ELISA. De plus, l’expression de gènes caractéristiques d’un état pro-inflammatoire des astrocytes sera déterminée par RT-qPCR. RÉSULTATS et CONCLUSIONS. Nous avons observé une diminution de l’expression de certains gènes indiquant un état pro-inflammatoire lorsque la kinase LRRK2 est inhibée, accompagnée d’une diminution significative de la sécrétion des cytokines pro-inflammatoire par les astrocytes. De plus, l’étude montre une variation dans le nombre de VEs sécrétées entre les astrocytes porteurs ou non la mutation LRRK2 G2019S ainsi qu’une variation dans leurs contenus. Ces résultats préliminaires suggèrent que la fonction kinase de la protéine LRRK2 régulerait la réponse des astrocytes à la signalisation microgliale pro-inflammatoire au cours de la MP.

Soumis par / Submitted by: AREVALO, Océane

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #55

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Enhancing neuronal survival in Parkinson’s disease: the protective role of RIT2 protein in transplantation therapy

BAILLOT LOUIS1, Obergasteiger Julia1, Ly Sothary1, Morin Béatrice1, Durcan Thomas2, Watter Valérie3, Hussein Samer3,4, and Lévesque Martin1,5.
1 CERVO Brain Research Centre, Centre, 2601, chemin de la Canardière, Québec, QC, Canada.
2 The Neuro – Montreal Neurological Institute, 3801, Rue University, Montréal, QC, Canada
3 St. Patrick Research Group in Basic Oncology, Oncology Division of CHU de Québec-Université Laval, Québec, QC, Canada
4 Department of Molecular Biology, Medical Biochemistry, and Pathology, Faculty of Medicine, Université Laval, Québec, QC, Canada.
5 Department of Psychiatry and Neurosciences, Faculty of Medicine, Université Laval, Québec, QC, Canada.

Parkinson’s disease (PD) is a chronic neurodegenerative disorder characterized by the accumulation of abnormal protein aggregates called Lewy bodies and the loss of dopaminergic neurons. Cell transplantation therapy for PD faces a challenge in ensuring the survival of transplanted neurons in the presence of toxic protein aggregates. Grafted neurons can develop alpha-synuclein pathology, limiting their long-term efficacy. Our recent study revealed that the RIT2 protein influences autophagy-related processes and pathologic alpha-synuclein clearance. RIT2 overexpression was found to protect dopamine neurons and mitigate motor dysfunctions in a preclinical PD model. These findings suggest that modulating RIT2 expression in grafted neurons may protect them from alpha-synuclein pathology. To investigate whether RIT2 overexpression could be beneficial for transplanted dopamine neurons against alpha-synuclein pathology, we generated dopamine neurons from human embryonic stem cells (ESCs). Using alpha-synuclein preformed fibrils as a PD model, we injected them into the striatum of adult immunocompromised mice. Purified human ESC-derived dopamine neurons overexpressing RIT2 were then transplanted into the substantia nigra. Locomotor scores were assessed monthly for six months post-transplantation, comparing them to pre-transplantation scores. Neuropathology was evaluated to assess the presence of Lewy body markers, examining whether RIT2 overexpression improves survival and protein aggregate clearance. Preliminary results indicate that RIT2 protects against alpha-synuclein pathology and enhances the survival of grafted dopamine neurons. These findings suggest that RIT2 modulation can improve the efficacy of cell transplantation therapy in PD.

Soumis par / Submitted by: Baillot, Louis

Affiliation: Centre de recherche CERVO

Résumé/Abstract #56

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Detection and Localization of Synaptic Anomalies in STED Microscopy Using Deep Learning

BEAUPRÉ, FRÉDÉRIC (1, 4); Gagné, Christian (3, 4); Lavoie-Cardinal, Flavie (1, 2, 4)
1. CERVO Brain Research Centre,
2. Université Laval, Department of Psychiatry and Neuroscience,
3. Université Laval, Department of Electrical and Computer Engineering,
4. Institute for Intelligence and Data

Synaptic dysfunction is a key hallmark of neurodegenerative diseases. On a population level, synaptic dysfunction is heterogeneous and tends to worsen with disease progression. We use super-resolution microscopy and deep learning-based anomaly detection to detect nanometric changes in synaptic protein organization at early time points in animal models of neurodegenerative diseases. The nanometric organization of synapses is measured with Stimulated Emission Depletion (STED) microscopy in primary neuronal cultures infected with viruses modulating the expression of key proteins involved in disease progression. Unlike traditional quantitative analysis methods, our deep learning approach automatically extracts features, allowing the detection of out-of-distribution synaptic nanostructures, including synthetically created anomalies, perforated synapses, and sparse fluorescent beads. More specifically, we train deep generative models such as normalizing flows, variational autoencoders and diffusion models to model the distribution of anomaly-free, nominal samples such that the networks can highlight regions deviating from the nominal distribution at inference time. Moreover, we adapt the Multiple Instance Learning framework to efficiently handle large images and uncover small and rare anomalies concealed in large fields of view. In ongoing work, the proposed methods are being applied to disease models of neurodegeneration, and could lead to discoveries of rare synaptic events that would be overlooked by classical detection and classification approaches of known features, thus radically changing the study of neurodegeneration.

Soumis par / Submitted by: Beaupré, Frédéric

Affiliation: Centre de recherche CERVO

Résumé/Abstract #57

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Central delivery of IL-1α promotes blood-CNS barrier disruption and IgG uptake in brain and spinal cord neurons

ANA BOISVERT1, Adrian Castellanos-Molina1, Audrée Laroche2, Eric Boilard2, Steve Lacroix1

1. Axe Neurosciences du Centre de recherche du Centre hospitalier universitaire (CRCHU) de Québec–Université Laval et Département de médicine moléculaire de l’Université Laval, Québec, G1V 4G2, QC, Canada.
2. Axe maladies infectieuses et immunitaires du CRCHU de Québec–Université Laval et Centre de recherche en arthrite de l’Université Laval, Québec, G1V 4G2, QC, Canada.

Spinal cord injury (SCI) leads to the release of alarmins from necrotic cells, leading to neuroinflammation and increased blood-spinal cord barrier (BSCB) permeability. We recently showed that the alarmin IL-1α is released by necrotic microglia after SCI. Thus, we injected recombinant mouse IL-1α intra-cisterna magna in adult mice to study the acute secondary events taking place in the CNS. Real-time in vivo microscopy revealed myeloid cell recruitment shortly after injection, correlating with BSCB disruption. Notably, BSCB permeability coincided with immunoglobulin G (IgG) infiltration and internalization in spinal cord (SC) and medullary reticular nucleus (MRN) neurons. Using a model of IL-1R1 restoration in endothelial cells (ECs) specifically, we found that IL-1R1 signaling in ECs drives the disruption of the BSCB, without recovering widespread IgG internalization in SC neurons. Further, a depletion of myeloid cells prevented BSCB disruption, while infiltration of IgG into neurons still occurred. This implies that myeloid cell-EC crosstalk initiates BSCB permeability, while IgG infiltration may occur independently of BSCB integrity loss. To elucidate the mechanisms through which IgG enters neurons in the brain and spinal cord, we conducted injections of IL-1α in a murine model lacking all activating Fc gamma receptors (Fcer1g-/-). Surprisingly, our investigation unveiled a comparable IgG infiltration into neurons in both the SC and MRN, suggesting that activating FcγRs have minimal involvement in this sequestration process. Moreover, IL-1α injections in mice lacking FcγRIIb (Fcgr2b-/-) exhibited similar patterns of neuronal IgG uptake, suggesting that this inhibitory receptor alone is not responsible for uptake. Lastly, in a model devoid of the neonatal Fc receptor (Fcgrt-/-), IL-1α i.c.m injections failed to induce IgG internalization within neurons, prompting us to investigate the role of FcRn as a potential mechanism for IgG transport across CNS barriers, and/or uptake of IgG by neurons. In summary, central administration of IL-1α results in heightened blood-CNS barrier disruption coupled with the internalization of IgGs within brain and spinal cord neurons via mechanisms presumably involving the neonatal Fc receptor, while the source of these infiltrating IgGs may be independent of CNS barrier permeability, suggesting that this IgG may originate from within the CNS itself.

Soumis par / Submitted by: Boisvert, Ana

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #58

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Traiter les dystrophies musculaires en corrigeant les mutations

Camille Bouchard, Joel Rousseau, Jacques P. Tremblay

La dystrophie musculaire de type 2B (LGMD2B) et la myopathie de Miyoshi (MM) sont deux résultats de mutations dans le gène de la dysferline. La protéine stabilise la signalisation Ca2+ et répare le sarcolemme dans le muscle squelettique. Dans ma famille, une mutation ponctuelle dans un nucléotide remplace un tryptophane par un codon STOP. La première partie de mon projet vise à corriger différentes mutations ponctuelles dans le gène de la dysferline in vitro à partir de lignées cellulaires immortalisées et la deuxième est de comparer l’efficacité et la sécurité de méthodes de livraisons jusqu’aux muscles chez la souris.
Mon hypothèse est que Prime editing pourrait corriger plusieurs mutations ponctuelles dans le gène DYSF.
La méthode utilisée est celle décrite par Anzalone et al en 2019. Un plasmide contenant l’ADN pour synthétiser les protéines Cas9n et la transcriptase inverse avec un ARNguide est livré dans les cellules. Trois jours après le traitement, l’ADN est extrait puis une PCR avec des amorces spécifiques à la région amplifie la séquence qui contient la mutation.
Le produit PCR est séquencé pour déterminer le pourcentage de correction.
La méthode est déjà bien connue des membres de mon laboratoire. En effet, nous avons déjà obtenu des pourcentages d’édition très favorables dans d’autres gènes, comme la dystrophine avec la même technique.

Pour la première correction de DYSF, nous avons obtenu jusqu’à 29% d’édition de la mutation E1833X et 31% pour la mutation R1905X in vitro. Mon projet de doctorat est de trouver la bonne construction pour corriger les mutations les plus fréquentes dans ce gène in vitro, puis ensuite d’évaluer les méthodes de livraisons aux muscles chez la souris. Je compare non seulement l’efficacité, mais surtout la sécurité des méthodes dans le but de ne pas causer de réponse immunitaire ou de toxicité aux patients.

Soumis par / Submitted by: Bouchard, Camille

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #59

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Mise en place d’une approche cartographique pour évaluer l’accessibilité des soins neurologiques pour les Premiers Peuples

BOULANGER CHARLOTTE, Jacquet Bastien, Dupré Nicolas, De Rus Jacquet Aurélie. Centre de Recherche du CHU de Québec et Département de Psychiatrie & Neurosciences–Université Laval, Québec, QC, Canada

Les études menées auprès des réseaux canadiens de personnes atteinte de la maladie de Parkinson (MP) comptent 0.4% d’échantillons biologiques issus de participant.e.s Autochtones. A l’échelle du Canada, iels représentent pourtant 5% de la population. On observe donc un manque de représentativité de ces populations au sein des panels de patient.e.s impliqué.e.s dans la recherche scientifique et pour l’analyse de leurs besoins au cours de la progression de la maladie. Pour ces raisons, les études de notre laboratoire s’intéressent à mieux comprendre les barrières qui limitent l’accès des Premiers Peuples aux ressources offertes par les réseaux de patient.e.s.
La faible représentativité des personnes atteintes de la MP chez les Premiers Peuples pourrait s’expliquer par un manque d’accessibilité aux soins neurologiques. Cet accès restreint retarderait alors leur diagnostic de la MP.
Cette étude a pour but de mettre en place des techniques de cartographie afin de visualiser les densités de populations des Premiers Peuples en comparaison des points d’accès aux soins neurologiques.
Les techniques de cartographie se font sur les logiciels ArcGIS et Maptitude. Les données utilisées proviennent des recensements Canadiens, de C-OPN (Canadian Open Parkinson Network) et RPQ (Réseau Parkinson Québec), ou de sites gouvernementaux. Des associations de couches de carte, c’est-à-dire de cartes possédant une information homogène, ont ensuite été réalisées pour obtenir un visuel final mettant en exergue les difficultés d’accès aux soins pour les populations Autochtones.
Ces cartes donnent un aperçu des obstacles rencontrés par les populations autochtones dans leur accès à des soins neurologiques. L’étude des cartes montre un éloignement géographique des hôpitaux. De plus, les services de transport entre ces deux points sont limités : il y a peu de routes et transports en commun. Par ailleurs, on observe que les services neurologiques sont concentrés dans les zones ayant une dense population allochtone de plus de 65 ans, ces services sont moins disponibles dans les territoires à forte représentativité Autochtone. Étant donné que la population Autochtone est proportionnellement plus vieillissante que le reste de la population canadienne, nos observations cartographiques renforcent la nécessité de mieux desservir ces territoires et mesurer l’impact de la MP. Ainsi, l’utilisation de la cartographie permet de proposer une analyse complémentaire à l’analyse numérique ou textuelle.

Soumis par / Submitted by: Boulanger, Charlotte

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #60

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Implication of non coding RNA in Huntington’s Disease

BOULAY, GABRIEL; Hébert, Sébastien
Centre de Recherche du CHU de Québec – Université Laval

La maladie de Huntington (MH) est une affection neurodégénérative héréditaire rare qui affecte 5-10 individus sur 100 000. La maladie est principalement caractérisée par une dégénérescence des neurones dans le striatum et le cortex qui entraîne une perte progressive des fonctions cognitives et du contrôle moteur. Au niveau moléculaire, la protéine huntingtine (HTT) joue normalement un rôle régulateur dans les cellules étant impliquées dans plusieurs procédés cellulaires. La MH est causée par la mutation et l’agrégation de la protéine HTT mutante, suivi d’une dérégulation précoce de la transcription. À cet égard, mon laboratoire hôte s’intéresse à la contribution des ARN non codants, dont les small nucleolar RNAs (snoARN), dans la MH. Les snoARN guident les modifications post-traductionnelles de l’ARN ribosomique (ARNr), médient l’épissage alternatif, et régulent l’expression génique de manière similaire aux microARN.

L’étude d’un jeu de données de séquençage de petits ARN comparant le transcriptome de 26 patients de MH et 49 patients contrôles obtenus de GEO a révélé que l’expression du groupe entier de snoARN est altérée dans le cortex préfrontal (BA-9) lors de la progression de la MH. Puisque l’expression des snoARN est altérée de manière globale lors de la progression de la maladie, nous croyons que les enzymes de maturation des snoARN, dont DKC1, FBL, NHP2, NOP10, GAR1, NOP56, NOP58 et SNU13, pourraient être affectés par la protéine HTT mutée. Les snoARN représentent une classe importante d’ARN non codant. Chaque snoARN étant potentiellement impliqué dans la régulation post-traductionnelle de l’ARNr, de l’épissage alternatif et de l’expression génique, la dérégulation de cette classe entière d’ARN a le potentiel d’affecter de nombreuses voies biologiques et joue sans doute un rôle dans la pathologie de la MH.

Soumis par / Submitted by: Boulay, Gabriel

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #61

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Altered PPIA/EMMPRIN pathway in the cellular communication of the peripheral nervous system during Amyotrophic Lateral Sclerosis.

BOYER MARION, Galbraith Todd, Berthod François, Pozzi Silvia, CERVO Brain Research Centre, 2601, Av. de la Canardière, Québec, QC, G1J 2G3, Canada

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the loss of upper and lower motoneurons. Neuroinflammation and oxidative stress, two hallmarks of ALS, associate with motor neurons death. Interestingly, neuromuscular junction (NMJ) denervation, is observed before neuronal death. The NMJ is a specialized tri-partite synapse of the peripheral nervous system (PNS) composed by terminal Schwann cells, post-synaptic muscles cells and pre-synaptic axon terminals.
In ALS central nervous system (CNS) Peptidyl-Prolyl Isomerase A (PPIA), a chaperone protein with cis-trans isomerase activity, is highly expressed and secreted by motoneurons and glial. Interestingly, in an ALS mouse model (SOD1G93A), inhibition of extracellular PPIA decreases neuroinflammation and increases mice survival. Extracellular PPIA binds to its receptor EMMPRIN (Extracellular Matrix MetalloProteinase Inducer) inducing NFκB pathway activation and the release of Matrix Metalloproteinase (MMPs) which are involved in motoneuron death (MMP-9), and in muscles and Schwann cells migration and differentiation (MMP-2 and MMP-9).
We hypothesis that in ALS the PPIA/EMMPRIN pathway might be altered also in the cellular communication of the PNS and that it could contribute to the observed NMJ denervation.
To mimic inflammation and oxidative stress primary culture of Schwann cells obtained from non-transgenic mice and a myoblast cells line (C2C12) were treated with TNFα (30ng/mL) and H2O2 (500µM) respectively. C2C12 were transfected with a plasmid expressing SOD1G93A as a model of ALS. PPIA, EMMPRIN and phospho-p65 (activated NFκB) expression were assessed by western blot.
Our results show that inflammation and oxidative stress induce an alteration of PPIA/EMMPRIN pathway in muscle and Schwann cells. Moreover, SOD1G93A mutation in muscle cells induces an increase in the expression and secretion of PPIA.
Although preliminary, this study shows alterations of the PPIA/EMMPRIN pathway in muscle and Schwann cells during inflammation and oxidative stress, as well as, in SOD1G93A conditions. Considering the neurotoxic and neuroinflammatory role of the pathway in the CNS of ALS mouse models, this study highlights for the first-time a possible involvement of PPIA and EMMPRIN in a pathological cross-cellular communication of the PNS which might contribute to NMJ denervation.

Soumis par / Submitted by: Boyer, Marion

Affiliation: Centre de recherche CERVO

Résumé/Abstract #62

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Circadian fluctuations in body temperature regulate Tau Secretion via the UPS-I Pathway: Implications for tau propagation in Alzheimer’s disease

CANET GEOFFREY, Da Gama Monteiro Felipe, Rocaboy Emma, Diego-Diaz Sofia, Hébert Sébastien, Lacroix Steve, Planel Emmanuel

The propagation of aggregated and hyperphosphorylated tau protein is a characteristic feature of Alzheimer’s disease (AD). However, the molecular processes governing its unconventional protein secretion (UPS) remain unclear. A recent study has found that tau levels in the interstitial fluid and cerebrospinal fluid (CSF) are increased during wakefulness compared to sleep. Moreover, we previously evidenced that tau phosphorylation follows a circadian pattern driven by the variations in body temperature (BT) during the sleep-wake cycle. Thus, we hypothesized that circadian BT variations play a significant role in UPS-mediated tau secretion.

In two neuronal models, we examined the impact of various temperatures (35-38°C), mimicking those experienced during the sleep-wake cycle, on UPS-related tau secretion. In wild-type mice, we evaluated changes in the expression levels of UPS-related proteins during the sleep-wake cycle, and following 6 hours of sleep deprivation (SD). Additionally, we subjected hTau mice (human tau overexpression) to hypo- or hyperthermia in order to influence tau levels in their CSF.

We demonstrated that wakefulness-like temperatures promote tau secretion. This process is primarily driven by the caspase-3-mediated cleavage of tau into TauC3. Furthermore, we identified that phosphatidylinositol 4,5-bisphosphate (PIP2) and syndecan-3 (SDC3) are upregulated at higher temperatures, and act as key players in tau export. Observations in mice revealed that wakefulness, as well as SD and mild-hyperthermia, correlate with increased expression of TauC3 and UPS-related proteins, ultimately resulting in elevated tau levels in CSF.

This study unveils a novel connection between BT fluctuations during the sleep-wake cycle and tau propagation, shedding light on potential therapeutic avenues for neurodegenerative diseases. These results also emphasize the importance of considering disruptions in both sleep and thermoregulation in the elderly population susceptible to AD.

Soumis par / Submitted by: Canet, Geoffrey

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #63

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Characterization of aggregation-prone regions of the huntingtin protein

Cardim-Pires, Thyago (1,2); Lepinay, Eva (1,2); Bérard, Morgan (3); Parent, Martin (3) and Cicchetti, Francesca (1,2)

(1) Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada.
(2) Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada.
(3) CERVO Brain Research Center, Quebec City, QC, Canada.

Huntington’s disease (HD) is a genetic condition caused by a mutation in Exon 1 of the huntingtin gene leading to an abnormal expansion of CAG repeats of the huntingtin protein (Htt). This mutation triggers its aggregation, accumulation in the brain as well as in peripheral tissues, ultimately leading to cell death and clinical manifestation. Htt is a protein composed of more than 3000 amino acids while Exon 1 accounts for less than 10 % of its entire structure. We therefore questioned whether other segments of the protein could drive aggregation. Using bioinformatics (Aggrescan and Amylpred2 algorithms) on the Htt structure (PDB: 6EZ8), we identified 110 segments (Hotspots) prone to aggregation outside Exon 1. Fifty-five are located in the N-terminal domain, 13 are found in the bridge and 42 in the C-terminal domain. Based on the in silico analysis of their aggregation propensity (by Aggrescan, TANGO, Amylpred2 and Cordax algorithms), we selected five aggregation-prone peptides (AgPP) to test in vitro: bP1 and bP4 (located at the N-terminal), bP6 (located at the Bridge) and bP8 and bP9 (located at the C-terminal). Under physiological conditions (37ºC and pH 7,4), all selected AgPP rapidly aggregated and could bind to Thioflavin T (ThT) (within seconds to minutes). N-terminal AgPP showed greater affinity to ThT than segments from the Brigde or the C-terminal domain. All AgPP produced amorphous aggregates after 72 h incubation, while amyloid fibrils were formed only by bP6 and bP8, as visualized by Transmission Electronic Microscopy (TEM). Dot-blot analysis revealed that all AgPP aggregates present affinity to anti-oligomers and anti-amyloid fibrils conformational antibodies (A11 and OC antibodies, respectively). While the incubation of AgPP in a pH 5,8 solution promoted the production of amyloid fibrils by all peptides, incubation at pH 8,0 favored the production of amorphous aggregates, as visualized by TEM. Our preliminary findings indicate that nonExon 1 components of Htt can also aggregate and therefore should be consider as important players in the pathology.

Soumis par / Submitted by: Cardim-Pires, Thyago

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #64

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Efficacité des inhibiteurs de l’acétylcholinestérase dans l’aphasie primaire progressive logopénique

CARRIER-AUCLAIR, JULIE 1,2,3
Lavoie, Monica 1,2
Tastevin, Maud 2,4
Laforce, Robert Jr 1,2,3
1. Clinique Interdisciplinaire de Mémoire, Département des Sciences Neurologiques du CHU de Québec, Québec, Canada;
2. Chaire de Recherche sur les Aphasies Primaires Progressives—Fondation de la Famille Lemaire, Québec, Canada;
3. Faculté de Médecine, Université Laval, Québec, Canada;
4. CH Montperrin, Aix-en-Provence, France

State of the art: For over twenty-five years, cholinesterase inhibitors (ChEIs) have been the main symptomatic treatment for Alzheimer’s disease (AD), and several meta-analyses have supported their efficacy. Most cases of the logopenic variant of primary progressive aphasia (lvPPA) are caused by a similar pathologic process than AD, yet no study has examined the efficacy of ChEIs in this clinical population. We aimed to explore the efficacy of ChEIs in the treatment of lvPPA by comparing their evolution on the MMSE to that of treated AD patients.
Methods: A retrospective chart review was performed in forty-five patients with lvPPA and fifty-two patients with amnestic AD. Both groups were similar in terms of age, level of education, and onset of symptoms. Drug history and MMSE scores were collected on several time points before and after the introduction of ChEIs for both groups, and clinical data was collected for lvPPA patients. Data was analysed using ANOVA and a generalized linear mixed model.
Results: Patients with lvPPA showed a similar trajectory of decline than amnestic AD patients on serial MMSEs up to twenty-four months after the introduction of ChEIs.
Conclusion: This study provides preliminary evidence for the efficacy of ChEIs in patients with lvPPA and suggests similar benefits to those seen in amnestic AD patients.

Soumis par / Submitted by: Carrier-Auclair, Julie

Affiliation: CRCHU de Québec-UL, pavillon HEJ

Résumé/Abstract #65

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Administration of an AAV encoding a scFv antibody targeting TDP-43 via intravenous delivery alleviates symptom phenotypes and pathology in a mouse model of vascular dementia

CHAMI ANNA1, Gravel Claude,1,2, Weng Yuan Cheng1, Kriz Jasna1,2, Julien Jean-Pierre1,2
1CERVO Brain Research Centre, Québec, Québec, Canada.
2Department of Psychiatry and Neuroscience, Université Laval, Québec City, Québec, Canada.

Vascular dementia is the second most common type of dementia after Alzheimer’s disease. This progressive disease is due to pathological reduction in cerebral blood flow. Some studies reported that Chronic Cerebral Hypoperfusion (CCH), one of the major causes of vascular dementia, is associated with neuronal damages, especially in the cortex and hippocampus regions and which leads to cognitive disorders. But the mechanistic link between the cerebrovascular pathology and the cognitive impairments remains elusive and currently, no cure does exist.
Recently, our lab generated a CCH mouse model by UCCAO (Unilateral Common Carotid Artery Occlusion). The mice subjected to UCCAO surgery exhibit severe TDP-43 pathology in cortical neurons, with cytoplasmic mislocalization of TDP-43, formation of insoluble phospho-TDP-43 aggregates, neuroinflammation and the development of cognitive and motor deficits.
Considering the pathological changes TDP-43 distribution and the cognitive impairment observed in the CCH mouse, we have tested the therapeutical potential of an adeno-associated virus (AAV) vector encoding a scFv (single-chain variable Fragment), called VH7Vk9, composed of the heavy and light chain hypervariable regions of a monoclonal antibody that binds specifically TDP-43.
Here, we used a new version of the AAV vector, bearing a recombinant capsid (B10) designed to achieve efficient neuronal transduction after injection directly into the bloodstream and allows efficient blood-to-brain transfer. The AAV-scFv anti-TDP-43 (and an AAV-scFv anti-GFP used as a control) were bilaterally injected intravenously in the retro-orbital sinus of CCH mice. This resulted in significant pan-neuronal expression of the encoded scFv in brain and spinal cord. We report that the intravenous injection of this AAV-delivered scFv anti-TDP-43 in CCH mouse model improved cognitive impairments and motor deficits caused by CCH. Moreover, expression of the scFv VH7Vk9 was able to reduce the number of cortical neurons with cytoplasmic TDP-43 aggregates.
Thus, intravenous administration of a single dose of AAV-B10 encoding scFv anti-TDP-43 Ab led to sustained production scFv Abs in neurons with ensuing beneficial effects in a mouse model of vascular dementia. The results support the view of a key role for TDP-43 in pathogenic changes associated with brain hypoperfusion and they suggest that antibody approaches targeting TDP-43 might provide new therapeutics for vascular dementia.

Soumis par / Submitted by: Chami, Anna

Affiliation: Centre de recherche CERVO

Résumé/Abstract #66

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

ALS fibroblast derived exosomes increase wound healing

CLÉMENT, VINCENT; Roy, vincent; Touzel-Deschênes, Lydia; Dupré, Nicolas; Gros-Louis, François.

Centre de recherche du CHU de Québec, Université Laval

Background and introduction
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative motor neuron disease leading to paralysis and death in patients 2 to 5 years after onset of the first symptoms of the disease. When Charcot first described ALS, he made observations on patient’s skin, noting that they didn’t develop bedsores as most bedridden patient’s do. Since then, other observations have been made linking nervous and skin tissue in ALS1,2. Exosomes are small microvesicles containing a complex cargo. Fibroblasts derived exosomes contain many proteins and factors related to multiple cell functions such as ECM building and remodeling, migration and proliferation3. With these observations, we hypothesised ALS cells secreted exosomes could increase would healing.
Methods
3D dermal fibroblast exosomes from healthy (6) and ALS (6) patients were isolated and characterized. Exosomal content was assessed by mass spectrometry and network analyses using Ingenuity Pathway Analysis (IPA). Migration and proliferation assays were performed using dermal fibroblasts isolated from ALS patients and healthy controls.
Results
Mass spectrometry and IPA analyses revealed that the studied exosomal proteins were more associated with Gene ontology biological functions such as ECM formation and cellular migration. IPA predicted increased migration and proliferation from dermal cells. It also predicted more ECM formation and less remodeling. A significant increase in cell migration was observed when adding ALS patient-derived exosomes on monolayered scratched wild-type cells, while effects on migration and proliferation alone were not significant.
Discussion
These findings reveled a novel exosome-dependant ECM deposition mechanism and suggest that the use 3D-fibroblast cellular culture may emerge as an innovative approach in precision medicine to study the role of exosome and patient derived ECM proteins in ALS. It also provides a potential explanation as to why patients do not develop bedsores, since fibroblasts ECM seems more stable and wound healing increased.

Soumis par / Submitted by: Clément, Vincent

Affiliation: CRCHU de Québec-UL, pavillon HEJ

Résumé/Abstract #67

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

SRSF3 modulates immune response in the APP/PS1 model of disease

Victor Coelho, Hejer Boutej, Sonia Djebbar, Jasna Kriz

Growing evidence suggests that chronic deregulation of innate immunity may represent one of the key elements in its pathobiology of Alzheimer’s disease (AD) and related neurodegenerative disorders. Rebalancing and/or strengthening the innate immune response has been proposed to be therapeutically relevant in AD. Microglia are the principal immune cells of the brain, and once activated, they can acquire a wide repertoire of immune profiles ranging from the classical pro to anti-inflammatory phenotypes. Its apparent profile shift is particularly evident in the context of chronic neurodegeneration. We recently described a novel ribosome-based regulatory mechanism orchestrated by the RNA binding protein (RBP) SRSF3. It controls innate immune gene translation in acutely activated microglia. SRSF3 is the smallest member of the serine/arginine RBP family involving in a wide array of biological processes in health and disease. Here, we aim to investigate the impact of SRSF3 as a regulator of innate immune response of activated microglia in AD. Brains of APP/PS1, presymptomatic and symptomatic mice were used to assess the expression level of amyloid beta (Abeta) peptides and disease-associated markers like TREM2, CD33, LILRB4a. WT age-matched littermates were used as controls. The levels of the active form of SRSF3 (pSRSF3) were also evaluated throughout the disease. Then, following the assessment of the disease, 1 year old APP/PS1 mice were treated intranasally with anti-SRSF3 antisense morpholino to reduce its level expression. The levels of pSRSF3/SRSF3, Abeta peptides, phagocytic, pro-inflammatory and neuronal markers were evaluated by western blot analysis while mice cognition was assessed by Passive Avoidance Task (PAT) and Novel Object Recognition (NOR) behavioural tests. With the progression of the disease, we observed an increase of Abeta peptides and pSRSF3/SRSF3 levels whereas the expression level of TLR2, TREM2 and LILRB4a did not change. Interestingly, treatment with anti-SRSF3-Morpho decreased the levels of Abeta peptides and increased the expression levels of microglial markers (TLR2, LILRB4a and TREM2) and the neuronal markers (synaptophysin and PSD95) in comparison to non-treated mice. In the PAT and NOR tests, recognition memory was improved by the treatment when compared to non-treated mice. Our results revealed that SRSF3 regulates expression patterns of targeted immune genes suggesting its immune-modulatory potential in AD-like pathologies.

Soumis par / Submitted by: Coelho, Victor

Affiliation: Centre de recherche CERVO

Résumé/Abstract #68

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Deciphering IL-1β-induced neurotoxicity in experimental autoimmune encephalomyelitis through proteomic analysis

DA GAMA MONTEIRO FELIPE, Lessard Martine, Vallières Nicolas and Lacroix Steve.
Neurosciences Axis of the CHU de Québec–Université Laval (CHUQ-UL) Research Center and Department of Molecular Medicine at Université Laval, Québec, QC, Canada

Background: The exact causes of multiple sclerosis (MS) are still poorly understood. Several factors, such as immune system dysfunction, genetics and the environment, seem to be involved in the disease. The presence of the proinflammatory cytokine interleukin (IL)-1 beta was previously correlated with the number and volume of brain MS lesions. Our recent work has demonstrated that the interaction between IL-1beta-producing monocytes and CD4+ T lymphocytes results in the production of factors that are toxic to neurons. Objective: The aim of this project is to identify the proteins responsible for the neurotoxic effects of IL-1 beta throughout the development and progression of experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Methods: To achieve this goal, novel quantitative proteomics approaches will be used to identify proteins mediating neuronal toxicity from conditioned media derived from myelin-reactive CD4+ T cells (2D2) cultured in the presence of IL-1 beta-competent myeloid cells. Results: We observed that IL-1 beta derived from myeloid cells participates in CD4+ T cell activation. We also demonstrated that conditioned medium derived from IL-1 beta-competent myeloid cells co-cultured with myelin-reactive CD4+ T cells significantly inhibits neurite outgrowth of embryonic cortical neurons. Conclusion: This project could help identify some of the IL-1 beta-dependent protagonists of EAE, and therefore potentially new therapeutic targets. We also aim to use the techniques that we will develop to validate our findings in human cells, since they could provide a simple, non-invasive method for assessing the contribution of immune cells to CNS damage in MS patients.

Soumis par / Submitted by: Da Gama, Felipe

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #69

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Functional optogenetic stimulation to reactivate paralyzed muscles in a rat model of peripheral nerve injury

DAGENAIS FRÉDÉRIC, Éthier Christian, Centre de recherche CERVO

Background: Functional electrical stimulation (FES) is a well-known technique that has been developed to restore loss of motor functions following peripheral nerve or spinal cord injuries. However, this tool presents many limitations. For example, it is associated with non-physiological recruitment of motor units that leads to gross movement and increased muscle fatigue compared to voluntary movement. Conversely, “functional optogenetic stimulation”, or FOS may present as an interesting alternative. It consists of injecting a viral construct into a muscle to enable the production of proteins called “opsins” along this muscle or the adjacent nerve. When expressed those opsins can depolarize to light leading to muscle contractions. FOS could allow a more natural order of motor unit recruitment, which could lead to finer and more reliable motor control.

Aim: To characterize the effectiveness of optogenetic muscle stimulation to restore fine movements and encourage muscle reinnervation after peripheral lesion in rats.

Hypotheses: 1- Optogenetic stimulation will allow finer movements and less fatigue than electrical stimulation. 2- It will lead to effective reinnervation after a lesion of the nerve.

Method: To test these hypotheses, an iterative approach is being used to identify a viral construct allowing efficient expression of opsins directly into the injected rat’s wrist flexor muscles or into the corresponding motor neurons. That is being assessed by monitoring muscle activity with electromyography (EMG) following optogenetic stimulation and by the immunohistology of the injected wrist flexor muscles, corresponding median nerve, and spinal cord of the rat. Furthermore, different opsins are being tested to obtain a wide variety of responses. Each opsin is being characterized by muscle recruitment curves in terms of force and evoked electromyographic activity. These responses will be compared to those of electrical stimulation in terms of resolution of achievable force and induced muscle fatigue. To assess muscle reinnervation, two groups of rats will be trained daily either by FES or FOS over four weeks. Then, the groups will be compared with an electrophysiology experiment (EMG, force) and with histological quantification (marking of neuromuscular junctions).

Conclusion: This project could raise new investigations and perhaps allow the early development of effective technologies to counter the debilitating consequences of neuromuscular lesions in humans.

Soumis par / Submitted by: Dagenais, Frédéric

Affiliation: Centre de recherche CERVO

Résumé/Abstract #70

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Développement d’une plateforme d’imagerie multimodale afin de quantifier la modulation noradrénergique sur l’activité vasculaire in vivo.

DAIGLE ANTOINE, Germain Gabrielle, Desjardins Michèle & Breton-Provencher Vincent

Centre de Recherche CERVO

La capacité du flux sanguin cérébral à répondre aux demandes locales est un élément important des techniques d’imagerie, comme pour l’imagerie par résonance magnétique fonctionnelle qui est grandement utilisée pour l’étude du fonctionnement du cerveau. Cependant, les mécanismes neuronaux qui contrôlent cette dynamique vasculaire durant le comportement animal sont peu compris. Notamment l’impact de la noradrénaline (NA), un neuromodulateur produit par le locus coeruleus, sur le comportement neurovasculaire est encore peu étudié. Impliquée dans l’apprentissage et la réponse comportementale, la NA pourrait avoir des effets modulateurs sur le couplage neurovasculaire. Cependant, les évidences actuelles du rôle de la noradrénaline dans la dynamique vasculaire proviennent de l’animal sous anesthésie et en utilisant des agents pharmacologiques plus ou moins spécifiques. Dans mon projet de maîtrise en biophotonique, l’objectif est de développer des outils pour mesurer précisément l’impact du relâchement de NA sur l’activité neurovasculaire dans le cortex cérébral d’une souris en comportement. Étudier l’interaction entre la NA, le système neurovasculaire et les neurones demeure un défi de taille, puisqu’il y a un manque de méthodes de bio-imagerie permettant d’observer ou de manipuler simultanément ces trois composantes. Nous utiliserons donc des techniques de neuroscience et d’imagerie modernes afin de vérifier notre hypothèse que le relâchement de noradrénaline peut moduler le flux sanguin en fonction des demandes comportementales.

Soumis par / Submitted by: Daigle, Antoine

Affiliation: Centre de recherche CERVO

Résumé/Abstract #71

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

CRISES ÉPILEPTIQUES RÉFRACTAIRES ET POLYNEUROPATHIE ASSOCIÉE À UNE DÉFICIENCE EN VITAMINE B6 CHEZ UN PATIENT TRAITÉ PAR LÉVODOPA/CARBIDOPA ORALE : UN RAPPORT DE CAS.

DÉRY CATHERINE 1, Labrecque Geneviève 2,3, Bouchard Manon 2,3 Dupré Nicolas 1.

1Centre de Recherche du CHU de Québec/Université Laval, Hopital l’Enfant-Jésus, Québec, QC, Canada,
2CISSS de Chaudière-Appalaches, Neurology, Levis, QC, Canada,
3Clinique Neuro-Lévis, Neurology, Lévis, QC, Canada

Contexte et objectifs :
La carence en vitamine B6 a été associée à une polyneuropathie et à des crises épileptiques réfractaires chez les patients traités à la lévodopa.

Méthodes :
Nous présentons le cas d’un homme de 69 ans atteint de la maladie de Parkinson (MP) depuis 11 ans, traité par lévodopa/carbidopa orale, qui a développé une polyneuropathie périphérique et des crises tonico-cloniques réfractaires.

Résultats :
Les tests de laboratoire ont révélé des niveaux de B6 très bas (11 nmol/L, normale 35-110), et aucune autre cause n’a pu être identifiée pour expliquer les symptômes du patient. Les crises du patient ont persisté malgré le traitement avec deux médicaments antiépileptiques. Suite à une supplémentation quotidienne de 25 mg de B6 par voie orale, les crises du patient ont cessé, et il a été autorisé à quitter l’hôpital.

Conclusions :
À notre connaissance, il s’agit du premier cas rapporté d’un patient traité par lévodopa/carbidopa oral présentant à la fois des crises réfractaires et une polyneuropathie associées à une carence en vitamine B6. Les enzymes qui décomposent la lévodopa nécessitent la B6 comme cofacteur, et des niveaux plasmatiques réduits de B6 ont été liés au traitement à la lévodopa. Bien qu’il y ait eu une préoccupation croissante concernant la carence en vitamine B6 et le risque de polyneuropathie ou d’épilepsie chez les patients traités à la lévodopa par gel intestinal (LCIG), notre cas indique que des préoccupations similaires devraient être soulevées chez les patients traités par de fortes doses de lévodopa/carbidopa administrée par voie orale. Nous proposons que le suivi des niveaux de vitamine B6 et B12 soit recommandé pour les patients prenant de fortes doses de lévodopa par voie orale, en particulier s’ils présentent des symptômes pouvant indiquer une polyneuropathie et/ou une épilepsie

Soumis par / Submitted by: Dery, Catherine

Affiliation: CRCHU de Québec-UL, pavillon HEJ

Résumé/Abstract #72

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

A ketogenic diet ameliorates mRNA translation and mitochondrial status in a mouse model of ALS

DESMEULES ANTOINE, Gelon Pauline A., Carmen Pelaez Mari, Dutchak Paul A., Sephton Chantelle F. Centre de recherche CERVO.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the death of upper and lower motor neurons leading to paralysis and muscle atrophy. In the early stages of the disease, ALS patients present a hypermetabolic state, resulting in lower body mass index and decreased fat stores. This imbalance in energy homeostasis could be due to a higher demand in energy coupled with an impairment in glucose metabolism. Our preliminary results show an accumulation of short and long chain acyl-carnitine a mouse model of ALS expressing the human Fused in sarcoma (FUS) R521G variant. Our previous work also shows that the mechanistic target of rapamycin (mTOR) pathway, a key regulator of metabolism, regulate FUS association with polyribosome to repress translation. This pathway can be regulated by dietary intake.
In this study, we aim to investigate potential dietary treatment in a mouse model of ALS. We wish to determine the impacts of a ketogenic diet and dietary restriction on the translational and mitochondrial status of a mouse model of ALS expressing the human FUSR521G variant. In order to do that, control and transgenic mice were put on a standard diet, a ketogenic diet for four weeks or starved for 24 hours. Behaviour tests were done pre and post diet.
Our results show that a ketogenic diet improves the cognitive performance and mildly improves motor performance in our mouse model of ALS. Furthermore, a ketogenic diet and dietary restriction increase the translational status of the transgenic mice. Transgenic mice also show lower energy levels in the brain. This phenotype is lost with the dietary treatment. We also found that the alteration in the mitochondrial status in the transgenic mice is recovered by treating them with a ketogenic diet.
Our study has shown that treatment with a ketogenic diet improves cognitive and motor functions. This improvement correlates with an increase in mitochondrial status and higher energy levels in the brain. The translational state of the mice was also increase. Future studies will focus on the regulation of mRNAs important for mitochondrial function by FUS and the impact of dietary treatment on the regulation of those mRNAs by FUS.

Soumis par / Submitted by: Desmeules, Antoine

Affiliation: Centre de recherche CERVO

Résumé/Abstract #73

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Comparaison de diverses méthodes de fixation pour l’étude de la phosphorylation de la protéine Tau par immunohistochimie

DIEGO-DIAZ S 1, Canet C 1,2 , Rocaboy E 1, Turgeon A 2, Gratuze M 1, Morin F 2, Cheng W.H 3, Wellington C 3, Hébert S.S 1,2, Planel E 1,2.

1 Université Laval, Faculté de Médecine, Département de Psychiatrie et Neurosciences, Québec, QC, Canada
2 Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada
3 Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada

L’hyperphosphorylation et l’agrégation de la protéine Tau sont des marqueurs histologiques et pathologiques de la maladie d’Alzheimer (MA). Pour étudier la phosphorylation de Tau en recherche préclinique, les cerveaux de souris modèles de MA sont souvent examinés par immunohistochimie. Cependant, la meilleure méthode de fixation n’est pas connue.
L’objectif de cette étude est de comparer différentes méthodes de fixation et de sectionnement afin de déterminer celle qui donne les meilleurs résultats par immunohistochimie. Trois lignées de souris différentes ont été utilisées : des souris non transgéniques (modèle B6), des souris avec une mutation sur la protéine Tau (modèle P301S) et des souris hTau (expriment tau humain sans mutation sur un fond Tau Knock-Out murin). Nous avons d’abord comparé la fixation par immersion de cerveaux de souris non transgéniques (avec ou sans hyperphosphorylation) dans la solution de Bouin comparé à du paraformaldéhyde (PFA) à 4 %. Les deux méthodes ont été testées avec ou sans perfusion saline avant fixation, et la fixation des cerveaux a été réalisée à 4°C ou à température ambiante. Ensuite on a fait l’inclusion dans la paraffine et les coupes. Enfin, une perfusion de Bouin ou de PFA 4% suivie d’une immersion dans le même fixateur a été testée à 4°C.
Nos résultats préliminaires indiquent que la fixation par immersion avec une solution de Bouin maintenue à 4°C semble être la meilleure méthode pour voir la phosphorylation de Tau et éviter la dégradation. Nous avons également observé que la perfusion avant la fixation donnait de mauvais résultats en raison de la déphosphorylation des protéines dans les cerveaux post-mortem. En conclusion, nos résultats montrent l’importance de choisir la bonne méthode de fixation pour l’étude de la protéine Tau afin de pouvoir voir un signal de phosphorylation optimal et d’obtenir de meilleurs résultats.

Soumis par / Submitted by: Diego Diaz, Sofia

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #74

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Detecting nanoscopic changes to mitochondrial morphology in human models of Parkinson’s Disease

FERGUSON, OWEN (1,2), Leclerc, William (1,3), Obergasteiger, Julia (1,2), Morin, Béatrice (1,2), Thériault, Kamylle (1,3), Lévesque, Martin (1,2), Lavoie-Cardinal, Flavie (1,2,3)

1 CERVO Brain Research Centre, Québec, Canada
2 Université Laval, Department of Psychiatry and Neuroscience, Québec, Canada
3 Institute for Intelligence and Data, Québec, Canada

Mitochondria are dynamic and sensitive organelles responsible for providing the majority of the brain’s energy, and their dysfunction has been implicated in Parkinson’s Disease (PD). In this project, we aim to show that PD alters mitochondrial morphology at the nanoscale.

To identify how PD affects mitochondria in humans, we characterized mitochondrial morphology features in dopaminergic neurons derived from PD patient stem cells harbouring genetic mutations and compared them to controls. By comparing images taken with confocal microscopy and STimulated Emission Depletion (STED) microscopy, we showed that visualizing mitochondria at the nanoscale with super-resolution tools allow for precise characterization of mitochondrial morphology and aids in describing how this morphology is altered in PD.

Preliminary results show that confocal images cluster multiple closely-packed mitochondria as single objects and therefore artificially increase average mitochondrial size. When these same images were examined with STED microscopy, we found that mitochondria in PD-associated neurons have a more fragmented phenotype than those in controls. The PD-associated mitochondria tend to have smaller areas, smaller aspect ratios, and increased circularity.

Future work includes investigating the effects of PD on mitochondrial morphology in different neuronal compartments by comparing somatic, dendritic, and axonal mitochondria between the control and PD groups.

Soumis par / Submitted by: Ferguson, Owen

Affiliation: Centre de recherche CERVO

Résumé/Abstract #75

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Is Information on Artificial Intelligent-Enhanced Hearing Aids Available on Social Media?

FERLAND JOANIE, Blouin Ariane, Guitton J. Matthieu, Sharp Andréanne Faculty of Medicine, Université Laval, Quebec City, QC, Canada; CERVO Brain Research Center, Quebec City, QC, Canada

With the aging of the population, hearing loss represents a major concern of public health. Hearing aids are the main way to compensate for hearing loss, yet conventional signal treatment algorithms often fall short of providing an optimal performance in noisy situations. The raises of Artificial Intelligence (AI) is opening new avenues for more powerful hearing aids. However, information available for patients regarding AI-enhanced hearing aids are only scarce. Our aim here was to evaluate the availability of online information on artificial intelligence-enhanced hearing aids for patients, focusing on information available on social media. Using a holistic online resource mapping and content analysis strategy from social media platforms (TikTok and Reddit), we explored the presence, type of information, availability, and actionability of information available for users. Our results demonstrate that: 1) some information regarding AI-enhanced hearing aids are indeed available online on social media, and 2) the material available on social media is mostly user-generated (and not primarily generated directly by the main hearing aids producing companies), however 3) the relevant information is extremely difficult to locate for users with a lower digital literacy (users less experienced in navigating through technology-based spaces), and 4) despite the amount of information available, there is still a clear paucity of information actually useable by uninformed patients.

Soumis par / Submitted by: Ferland, Joanie

Affiliation: Centre de recherche CERVO

Résumé/Abstract #76

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Étude du rôle de l’IGF-1 dérivé des microglies dans leurs capacités réparatrices après démyélinisation du système nerveux central.

JULIETTE FERRY, Adrian Castellanos-Molina, Nicolas Vallières, David Gosselin, et Steve Lacroix
Axe Neurosciences du Centre de recherche du CHU de QuébecUniversité Laval, Département de médecine moléculaire de la Faculté de médecine de l’Université Laval. Québec, QC, Canada.

Les microglies sont les cellules immunitaires résidentes du système nerveux central (SNC). Leur implication dans la phagocytose des débris de myéline et la remyélinisation du SNC est particulièrement pertinente dans des pathologies neurologiques démyélinisantes comme la sclérose en plaques. Dans ce contexte les microglies adoptent des phénotypes associés aux dommages, lesquels sont fréquemment liés à l’expression du gène Igf1. En revanche les mécanismes par lesquels la microglie aide à la remyélinisation sont encore flous. Étant donné que le facteur de croissance analogue à l’insuline de type 1 (IGF-1) est impliqué dans la signalisation cellulaire, régulant la prolifération, la différenciation, la migration et la survie, il est logique de se demander si l’IGF-1 pourrait jouer un rôle primordial dans les efforts de réparation du SNC par les microglies. Notre hypothèse est que l’IGF-1 dérivé des microglies serait un médiateur de l’efficacité des microglies à réparer le SNC. Pour tester cette hypothèse, nous avons produit les souris transgéniques Cx3cr1CreER::Igf1fl/fl dont les microglies sont conditionnellement invalidées en IGF-1 après un traitement au tamoxifène. Nous avons étudié les effets de cette mutation en combinaison à un traitement à la cuprizone lors duquel la mort des oligodendrocytes matures et la démyélinisation subséquente sont suivies d’une forte microgliose. Après 5 semaines de traitement à la cuprizone suivi d’une semaine de récupération, la délétion du gène Igf1 est associée à une augmentation de la quantité de myéline intacte/non phagocytée et une diminution du nombre d’oligodendrocytes dans le corps calleux. En parallèle, les souris cKO montrent une augmentation du nombre de microglies en prolifération et de celles exprimant les marqueurs de surface Cd11c et Ly9. Nos résultats suggèrent donc que l’IGF-1 dérivé des microglies jouerait un rôle dans la clairance des débris de myéline par les microglies.

Soumis par / Submitted by: Ferry, Juliette

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #77

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Local regulation of FUS by mTOR signalling pathways

GLASSON BASTIEN, Yousri Benchaar, Valerie Clavet-Fournier, Antoine Desmeules, Flavie Lavoie-Cardinal and Chantelle F Sephton

Mutations in the gene encoding the RNA-binding protein fused in sarcoma (FUS), are associated with amyotrophic lateral sclerosis (ALS) familial forms. Mutated FUS is predominantly present in the cytoplasm, which correlates with decrease in protein synthesis. mTOR signalling pathway is essential for regulation of local protein synthesis and synaptic plasticity. Recently, we showed that the mTORC2 signaling pathway affects the cytoplasmic localization of FUS and increased his association with stalled polyribosomes and inhibits protein synthesis in HEK293T cells.
OBJECTIVE Investigate the regulatory role of mTORC2 in FUS function in neurons and whether defects in mTORC2 signaling can further exacerbate cytoplasmic toxicity caused by ALS-linked FUS mutations
METHODS Primary cortical neurons were treated with Torin1, which inhibits the mTORC1 and mTORC2 pathways or Rapamycin, which inhibits the mTORC1 pathway. STimulated Emission Depletion (STED) microscopy provided images of FUS protein, ribosomes (60s ribosomal subunit) and vesicular glutamate transporter 1 VGLUT1. Acute slices were treated with DMSO, Torin1, Rapamycin. We isolated synaptoneurosomes (SN) from these slices.
RESULTS After mTOR pathway inhibition, FUS is recruited more abundantly to the cytoplasm. Inhibition of mTORC1 pathway is not sufficient to induce a significant change in FUS localization. We also investigate ALS-linked FUS mutants R521G and there are localized more predominantly to the cytoplasm. With Torin1 acute slices treatment, there is a decrease in the downstream effectors of mTORC1 and mTORC2, respectively pS6 and pAKT. Treatment with rapamycin causes a decrease only for pS6. Preliminary results show an increase in FUS expression with Torin1 treatment in the SN fraction. Next, we investigated the inhibition impact of translational activity on the interaction between FUS and ribosomes localized at synapses. STED microscopy show that with Torin 1 treatment, FUS localized near the 60S ribosomal subunit at the presynaptic region.
CONCLUSION These results suggests a potential role of FUS in the regulation of local translation in the context of translation inhibition. Future studies will examine the effects of mTORC2 on ALS-linked FUS mutations and identify the mRNA targets translationally repressed by FUS.

Soumis par / Submitted by: Glasson, Bastien

Affiliation: Centre de recherche CERVO

Résumé/Abstract #78

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Study of aggrecan remodeling in the spinal cord of a mouse model of amyotrophic lateral sclerosis.

GOSSELIN ARIANE, Barbeau Annie, Godin G. Antoine and Pozzi Silvia
CERVO Brain Research Centre
Department of Psychiatry and Neurosciences, Université Laval

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the selective death of lower and upper motor neurons, leading to paralysis of voluntary muscles.
The extracellular matrix (ECM), a complex network of molecules surrounding cells in tissues, plays a critical role in maintaining the structural integrity of the nervous system and is involved in various physiological processes. Studies have shown that ECM reorganization occurs during neurodegenerative diseases, but few studies, and with contradictory observations, are present in the ALS context. Since the ECM is involved in several cellular processes and provides protection and support for neurons and tissues, it is likely that ECM remodeling may affect the survival of motor neurons. Understanding which components of the ECM are dysregulated in ALS could improve our understanding of pathologic events and could help in the development of new therapeutic interventions.
The aim of this project is to investigate ECM remodeling in the lumbar spinal cord of SOD1G93A, an animal model of ALS, compared to age-matched healthy mice by western blots and immunofluorescence. Here, we focused on the analysis of aggrecan, one of the main components of the perineuronal net (PNN), the functional extracellular structure that surrounds neurons. In this ALS model, aggrecan expression is altered when compared to non-transgenic controls. In western blots analysis, aggrecan expression is reduced already in the early stages of the disease. In immunofluorescence analysis, global aggrecan signals in the ventral horn of the lumbar spinal cord are reduced at the symptomatic stage. As for the analysis of aggrecan-based PNN, the percentage of motor neurons surrounded by PNN (PNN+ MNs) is reduced at the symptomatic stage compared to non-transgenic controls. Although their number decreases, the structure of PNN in spared MNs is preserved, which could suggest a protective effect of the structure.
These results give new insights on the pathological mechanisms involved in ALS and suggest that ECM is altered during the disease and might have a protective role toward motor neurons.

Soumis par / Submitted by: Gosselin, Ariane

Affiliation: Centre de recherche CERVO

Résumé/Abstract #79

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

GATOR1-dependent mitochondrial regulation in astrocytes

IMANE HADJ-AISSA1, Chantelle Sephton1 and Paul Dutchak1
1Department of Psychiatry and Neuroscience, Université Laval, CERVO Brain Research Centre, Québec

Epilepsy is a neurological disorder affecting 1% of the Canadian population. GATOR1 is a cytoplasmic protein complex composed of NPRL2, NPRL3 and DEPDC5.A mutation in either subunit can result in loss of function of GATOR1 that will lead to focal epilepsy, autism, cortical malformations and hyperactivation of mTORC1. GATOR1 functions as an amino acid “sensor” that regulates the balance of protein synthesis and protein degradation by regulating the mTORC1 pathway. During amino acid deprivation, GATOR1 is necessary to catalyze RAG-GTP hydrolysis and repress amino acid consumption by inhibiting mTORC1. Amino acid sufficiency prevents GATOR1 from inhibiting mTORC1.
When GATOR1 is mutated, mTORC1 is activated even during amino acids starvation which lead to an increase in protein translation, anapleurosis in mitochondria, a decrease in autophagy and pyruvate entry to mitochondria. The entry of pyruvate into mitochondria is controlled by the pyruvate dehydrogenase (PDHE1) enzyme. When this enzyme is phosphorylated, it’s inhibited, and the pyruvate can’t entry the mitochondria. This phosphorylation of PDHE1 is controlled by the pyruvate dehydrogenase kinase (PDK) which 4 isoforms exists and their expression is dependent of the cell type.
Astrocytes are cells that maintain metabolic homeostatic mechanisms that influence neuronal precursors for synaptic transmission.
The Hypothesis is that a loss of function of GATOR1 contributes to the epileptic phenotype by affecting the astrocytes.
To test this hypothesis, we have generated:
• a mouse model, the GFAP-NPRL2 KO line, that are KO for NPRL2 in astrocytes.
• An astrocyte specific model, KO for NPRL3
The goal of this project is to investigate the consequence of the loss of function of GATOR1 in astrocytes:
• Characterize the GPAF-NPRL2 KO mice
• Understand the mitochondrial regulation when GATOR1 is not functional in astrocytes
The GFAP-NPRL2 mice have a hyperactivation of mTORC1 at 2 months and 5 months but the astrogliosis phenotype only appears at 5months in the hippocampus.
In the astrocytes NPRL3 KO, the TCA cycle is dysregulated by NH4+ production. In those cells the enzymes of the glutamine-glutamate metabolism are up-regulated to compensate the production of NH4+ and TCA cycle dysregulation.

Soumis par / Submitted by: Hadj-Aissa, Imane

Affiliation: Centre de recherche CERVO

Résumé/Abstract #80

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Les troubles de la production orale des mots dans la maladie d’Alzheimer et dans la variante logopénique de l’aphasie primaire progressive

HASANOVIC, AMRA (CIRRIS)., Monetta, Laura (CIRRIS)., Macoir, Joël (CERVO).

Les troubles neurocognitifs majeurs, tels que la maladie d’Alzheimer (MA) et la variante logopénique de l’aphasie primaire progressive (vlAPP) sont reconnus pour présenter des difficultés langagières associées à leur condition, et les troubles de la production orale des mots font partie de ces difficultés. Le modèle théorique d’architecture fonctionnelle (Caramazza et Hillis, 1990) permet de décortiquer la production orale de mots en différentes composantes sous-jacentes (sémantique, lexicale et post-lexicale), ainsi les troubles observés peuvent être expliqués par des déficits à l’une ou l’autre de ces composantes. L’objectif de la présente étude est de recenser les informations existantes à ce jour quant à l’origine fonctionnelle (sémantique, lexicale ou post-lexicale) des déficits observés en production orale de mots chez ces deux populations. Une revue systématique de la littérature a été réalisée à ces fins à partir de quatre bases de données. Un total de 21 études regroupant 429 patients avec MA et 57 avec vlAPP ont été sélectionnées. Les résultats montrent des origines sous-jacentes différentes pour les patients présentant une MA et ceux présentant une vlAPP. En effet, chez les individus atteints de MA, le déficit semble clair et se situerait principalement au niveau sémantique ou aux niveaux lexical et sémantique, en fonction, entre autres, de l’avancement de la maladie. Pour les patients atteints de la vlAPP, les résultats sont davantage hétérogènes, et l’origine sous-jacente demeure méconnue. La présente étude contribue à faire le point sur les troubles de la production orale des mots dans la MA et la vlAPP, toutefois plus d’études seraient à réaliser pour préciser le déficit sous-jacent aux troubles de la production orale des mots dans la vlAPP.

Soumis par / Submitted by: Hasanovic, Amra

Affiliation: CIRRIS

Résumé/Abstract #81

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Alpha-synuclein aggregation in Parkinson’s disease

IDI WALID, Bérard Morgan, Teixeira Maxime, Sheta Razan and Oueslati Abid
CHU de Quebec Research Center, Axe Neuroscience and Department of Molecular Medicine, Université Laval, Quebec, QC GIV 4G2. Canada

Parkinson’s Disease (PD) is the second most common neurodegenerative disease in the world. One of the major pathological hallmarks of the disease is the aggregation of a misfolded protein called alpha-synuclein (a-syn), which will lead to the formation of cellular inclusion known as Lewy bodies. However, how these aggregates disturb neuronal homeostasis leading to neurodegeneration remains elusive. Several studies showed a correlation between alterations of degradation systems (autophagic or proteasomal), implicated in protein quality control, and a-syn aggregation. Nevertheless, it is not clear yet how the degradation is impaired.
Our aim is here to know precisely how an alteration of the degradation systems is involved in the pathogenesis of PD.
To study the effects of a-syn aggregation, the LIPA (Light-Inducible Protein Aggregation) system recently developed by our laboratory is used. This system nicely mimics key features of Lewy bodies and allows us to control and observe optogenetically the aggregation of a-syn in real-time.
With this model, we could observe for the first time the effect of LIPA-induced aggregates on proteasome and autophagy systems by using specific markers. Moreover, we also get interested in inhibiting these systems and seeing the effect on the aggregation.
Taken together, our observations reveal the impact of autophagy and proteasome dysfunctions in PD pathogenesis. Interestingly, we found that both systems seem to be involved during the process of a-syn aggregation, but in a different manner and with a different kinetic.

Soumis par / Submitted by: Idi, Walid

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #82

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

KCC2 as a novel biomarker and therapeutic target for motoneuron degenerative disease

KHADEMULLAH, SAHARA, CERVO Brain Research Centre, Université Laval
Bourbonnais, Julien, CERVO Brain Research Centre, Université Laval
Chaineau, Mathilde M., The Neuro, McGill University
Castellanos-Montiel, Maria Jose, The Neuro, McGill University
Keramidis, Iason, CERVO Brain Research Centre, Université Laval
Legault, Alexandra
Paquet, Marie-Ève, CERVO Brain Research Centre, Université Laval
Abrahao, Agessandro, Sunnybrook Health Science Centre, University of Toronto
Zinman, Lorne, Sunnybrook Health Science Centre, University of Toronto
Robertson, Janice, Department of Laboratory Medicine and Pathobiology and Tanz Centre for Research into Neurodegenerative Diseases, University of Toronto
Durcan, Thomas, The Neuro, McGill University
Woodin, Melanie, Department of Cell and Systems Biology, University of Toronto
Godin, Antoine, CERVO Brain Research Centre, Université Laval
De Koninck, Yves, CERVO Brain Research Centre, Université Laval

Hyperexcitability in cells throughout the corticospinal tract is a presymptomatic feature of amyotrophic lateral sclerosis (ALS) associated with lethal motor degeneration. Disinhibition is a possible cause of this hyperexcitability, potentially implicating the central nervous system-specific potassium-chloride cotransporter, KCC2, a core regulator of the strength of GABAergic neurotransmission linked to several neurological disorders. Here, we show that KCC2 is downregulated in the membrane of motor cortex neurons from post-mortem SOD1-, C9orf72- and sporadic ALS patients. Increased protein levels of KCC2 were found in plasma and cerebral spinal fluid of ALS patients and mice harbouring the SOD1*G93A mutation. Longitudinal analysis of disease progression in both SOD1*G93A and Prp-TDP43*A315T mice revealed a decrease of KCC2 membrane levels in cortical and spinal motor neurons which were already present at the presymptomatic phase. Using KCC2-enhancing compounds, CLP290 and prochlorperazine (PCPZ) restored KCC2 membrane expression and function, delayed motor deficit onset, and extended lifespan by up to two months in mutant mice. Human-derived neurons differentiated from iPSC harbouring the SOD1*G93A mutation displayed KCC2 deficits which PCPZ treatment rescued. Acute administration of KCC2 enhancers restored chloride transport in presymptomatic and symptomatic mice and reversed motor neuron hyperexcitability in awake behaving mutant mice. These findings identify KCC2 as both an early biomarker and a disease-modifying therapeutic target for ALS.

Soumis par / Submitted by: Khademullah, Sahara

Affiliation: Centre de recherche CERVO

Résumé/Abstract #83

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Single-axon tracing of the subthalamic nucleus afferent projections arising from the external pallidum in cynomolgus monkeys

Talha Ahmed Khan
Martin Parent

The subthalamic nucleus (STN) is a key component of the basal ganglia, a set of subcortical structures involved in motor behaviour. Being mostly composed of glutamatergic neurons, the STN is often considered as the major driving force of the basal ganglia. Neurons of the STN project to the internal and external pallidum, the striatum and the substantia nigra pars reticulata. In turn, they receive afferent projections arising from the cerebral cortex, the external pallidum (GPe), the pedunculopontine tegmental nucleus, as well as from raphe and intralaminar thalamic nuclei. Our lab has recently described the glutamatergic STN afferent projections arising from the cerebral cortex and forming the hyperdirect pathway. The main objective of the present study is to characterize STN GABAergic afferent projections arising from the GPe. To achieve this goal, we have used intracerebral microiontophoresis bilateral injections of the anterograde tracer, biotin dextran amine (BDA), in cynomolgus monkeys (Macaca fascicularis). This method enabled the identification of firing patterns of GPe neurons to be injected and yielded a detailed view of their entire axonal arborization. The GPe neurons were easily recognizable by their spontaneous firing pattern that includes high-frequency discharges with pauses. The injection loci is composed of a dense core of BDA precipitate surrounded by 5-15 neurons labeled in a Golgi-like manner. Most of the GPe BDA-labeled neurons display long, aspiny and poorly branched dendrites that arborize mostly along the sagittal plane. Labeled axons can be followed individually throughout serial sagittal sections and reconstructed entirely with the help of a computerised 3D image-analysis system (Neurolucida, MicroBrightField). BDA-filled GPe axons found in the STN displayed large axon varicosities that are often apposed to the soma and proximal dendrites of STN neurons. Abnormal firing patterns of STN neurons is known to occur in Parkinson’s disease and the contribution of STN afferent projections arising from the GPe to this abnormal firing pattern is largely unknown. The information gathered here through the mapping of STN afferent axonal projections will help to refine a computational model of STN deep brain stimulation (DBS) used to alleviate motor symptoms of Parkinson’s disease.

Soumis par / Submitted by: Khan, Talha

Affiliation: Centre de recherche CERVO

Résumé/Abstract #84

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Le microARN-132 comme thérapie génique de remplacement pour la maladie d’Alzheimer

KHELAIFIA BOUTHEYNA ; goupil claudia ; munoz douglas ; hébert sébastien
Université Laval, Faculté de Médecine , Département de Psychiatrie et Neurosciences, Québec, QC, Canada
Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada
Department of Medicine, Queen’s University, Kingston, ON, Canada.

Contexte et objectifs
La maladie d’Alzheimer (MA) est une maladie neurodégénérative incurable et constitue la cause principale de démence. Elle implique un déclin cognitif lent et progressif et ses caractéristiques pathologiques comprennent des plaques Aβ et des enchevêtrements neurofibrillaires, provoquant la mort des neurones. Des altérations de l’expression des miARN ont été associées à la MA et miR-132 a été identifié comme le plus fortement régulé à la baisse durant sa progression. Fait intéressant, le traitement de souris Alzheimer avec une mimique du miR-132 (miR-132m) améliore grandement les pathologies et la mémoire. Une thérapie de remplacement du miR-132 pourrait donc être bénéfique aux patients. L’objectif de cette étude est de caractériser la pharmacocinétique et la biosécurité du miR-132m chez le primate.
Méthodes
Nous avons utilisé des singes cynomolgus naifs auxquels nous avons injecté un miR-132m fluorescent au niveau de la cisterna magna. Des prélèvements de liquide céphalo-rachidien (LCR) et de sang ont été effectués et les animaux ont été euthanasiés 72 heures après injection. Une dissection des tissus du CNS a été réalisée. Des quantifications du miR-132m et des miARN associés à la neuro-inflammation (miR-155, miR-146a) et dégénérescence (miR-124) ont été réalisées par qRT-PCR. De plus, une étude pilote de biosécurité a été effectuée chez des singes traités avec du miR-132m non-modifié par infusion intrathécale durant 30 jours. Des tests sanguins ont été effectués pendant ce traitement.
Résultats
Nous avons observé une augmentation nette du miR-132m dans le LCR (jusqu’à 8 heures après l’injection), le sérum (jusqu’à une heure après l’injection) et différents tissus (en post-mortem), dont le cortex entorhinal, le mésencéphale, le pont, le cervelet et la moelle épinière. À l’inverse, les autres miARN sont demeurés stables. Finalement, aucun signe de toxicité a été observé après une infusion continue du miR-132m dans le LCR.
Conclusions
Ces résultats suggèrent que l’injection d’un miR-132m directement dans le LCR est efficace et bien toléré par l’organisme. Des études sont en cours pour évaluer la distribution cellulaire ainsi que les gènes ciblés par le miR-132m dans le CNS. Ces études serviront à développer des études cliniques de phase I chez l’humain.

Soumis par / Submitted by: Khelaifia, Boutheyna

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #85

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Understanding Peripheral Blood Barrier Function in Huntington’s Disease ; Shedding Light on Pulmonary Vascular Dysfunction

LALA BOUALI, MOHAMED ; Hébert, Sébastien
Centre de Recherche du CHU de Québec, Université Laval

The primary cause of death in patients with HD is respiratory failure, usually due to aspiration pneumonia. While interventions such as lung expansion exercises may be employed to prevent respiratory complications in HD, there needs to be more understanding of the molecular mechanisms contributing to lung impairment. It is also vital to determine whether respiratory dysfunction occurs in the early or late stages of the disease.
To address this, our laboratory will investigate lung and respiratory deficits in HD individuals and mouse models with the goal of providing new biological insights and optimized therapeutic approaches.
Specifically, we will focus on biological barriers that protect organs and tissues from physical, chemical, and biological damage and maintain homeostasis within the tissues. For example, it is now well accepted that changes in the blood-brain barrier (BBB) are an important determinant of HD disease progression and symptoms. Consistent with this idea, we could identify significant alterations in BBB protein levels (e.g., ZO1, Occludin, and Claudin-5) throughout the human and mouse HD brains. Interestingly, the BBB is naturally connected with the lungs and respiratory system. For instance, lung injury caused by abnormal mechanical ventilation – with incorrect CO2 levels or tidal volume settings – can lead to increased BBB permeability and, consequently, brain dysfunction. A direct insult to the lungs can promote functional defects associated with increased alveolar-capillary barrier (ACB) permeability. Impairment or loss of resilience in the ACB plays a major role in developing pneumonia, in addition to a weakened host immune system. Finally, the lung’s inability to efficiently exchange gases may lead to impairments in brain regions particularly vulnerable to hypoxemia, such as the hippocampus and putamen.
Based on these observations, we aim to better understand the relationship between the brain and lungs, explicitly focusing on biological barrier dysfunction. We hypothesize that early changes in ACB proteins (expressed mainly in the lung’s endothelial and epithelial cells) are critically involved in respiratory deficits and increased susceptibility to lung infections observed in HD individuals. In preliminary data, we observed changes in key ACB proteins in the lungs of adult zQ175 HD mice. Complementary studies are underway in young (including asymptomatic) mouse models of HD (e.g., zQ175 mHTT knock-in mice) to characterize the lung at biochemical and functional levels, including the quantification of ACB proteins in isolated microvessels, transcriptomics, in vivo pulmonary function and permeability tests, infection susceptibility, and the assessment of the inflammatory states in both the lung and brain during disease progression. We are also going to corroborate these studies in human HD lung tissues in order to move our innovative research forward.

Soumis par / Submitted by: LALA BOUALI, Mohamed

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #86

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

IMPACT DE LA DELETION DE TAU DANS UN MODELE MURIN DE LA MALADIE DE HUNTINGTON

LEPINAY EVA 1,2, alpaugh melanie 3, saint-pierre martine 1, teixeira maxime 1,4, snapyan marta 5, oueslati abid 1,4, parent martin 5, cicchetti francesca 1,2
1Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada; 2Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada; 3Department of Molecular and Cellular Biology, University of Guelph; 4Département de Médecine moléculaire et cellulaire; 5Centre de recherche CERVO, Québec, QC, Canada

La protéine tau est essentielle à la formation et stabilisation des réseaux microtubulaires et une fonction altérée a été associée à des états pathologiques caractéristiques des tauopathies – sous-classe de troubles neurodégénératifs caractérisés par le dépôt de protéines tau anormales dans le tissu cérébral. Ces dernières années, il est suggéré que la protéine tau contribue à la pathologie de la maladie de Huntington (MH) – maladie neurodégénérative caractérisée par des déficits moteurs, cognitifs et psychiatriques. HYPOTHÈSE. Nous avons émis l’hypothèse que la protéine tau est impliquée dans le développement des phénotypes comportementaux et neuropathologiques associés à la MH. MÉTHODES. Des souris zQ175 ont été croisées avec des souris knockout tau (mTKO) et des tests comportementaux ont été réalisés à 3, 6, 9 et 12 mois pour évaluer l’anxiété et les déficits cognitifs et moteurs en fonction de la présence ou absence de tau. Les analyses post-mortem actuelles comprennent la quantification des niveaux solubles/insolubles d’huntingtine (Htt) et Htt mutée (mHtt) et l’organisation microtubulaire par microscopie. RÉSULTATS. Nos résultats suggèrent une précipitation et une aggravation des déficits moteurs et des déficits cognitifs chez les souris zQ175/mTKO. Nos données post-mortem montrent une diminution des niveaux d’Htt/mHtt solubles, une augmentation des niveaux insolubles de la protéine ainsi qu’une désorganisation microtubulaire chez les souris zQ175/mTKO. CONCLUSION. Nos observations suggèrent que tau jouerait un rôle important dans la MH. Des analyses post-mortem approfondies feront la lumière sur la relation entre les protéines tau et mHtt et le développement des déficits dans la MH.

Soumis par / Submitted by: LEPINAY, Eva

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #87

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Caractérisation du transport de la protéine de liaison au facteur de croissance de l’analogue de l’insuline (IGFBP2) et du facteur de croissance des fiibroblastes 21 (FGF21) à travers la barrière hémato-encéphalique.

LINHARES SABRINE, Manon Leclerc, Dominique Seguin, Louise Reveret, Josue Valentin-Escalera, Vincent Emond, Frédéric Calon. Faculté de Pharmacie, Université Laval, Québec, Québec, Canada. Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Québec, Canada. Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, Québec, Canada.

PROBLÉMATIQUE : Le facteur de croissance des fibroblastes 21 (FGF21) est une hormone principalement sécrétée par le foie, avec des effets sur l’homéostasie du glucose et des lipides, ainsi que sur la sensibilité à l’insuline. D’autre part, l’« Insulin-like growth factor-binding protein 2 » (IGFBP2), qui appartient à la famille des IGFBP, est la plus exprimée de sa classe dans le cerveau. En se liant aux IGF-I et II, elle module leurs biodisponibilités et leurs effets métaboliques. Nous émettons l’hypothèse que ces deux molécules soient impliquées dans la maladie d’Alzheimer (MA), dans laquelle des déficits métaboliques sont observés chez les patients.
OBJECTIF : Déterminer si ces molécules traversent la barrière hémato-encéphalique (BHE) pour agir directement au cerveau. MÉTHODOLOGIE : La perfusion cérébrale intracarotidienne a été utilisée pour quantifier et caractériser le transport du 3H-IGFBP2 et du 3H-FGF21 à travers la BHE chez la souris.
RÉSULTATS : Nous avons démontré que le 3H-FGF21 et le 3H-IGFBP2 traversent la BHE avec un coefficient de transport cérébral (Clup) de environ 0.30 µl.g-1.s-1. La captation de 3H-FGF21 est saturable mais n’a pas été impactée par les inhibiteurs de la phosphorylation de son récepteur (ASP5878 et BJG398). La coperfusion avec PSC833 (inhibiteur de la pompe à efflux P-gp) ou Elacridar (inhibiteur de la P-gp et de la BCRP) a augmenté le Clup de +200% et +600%. Le transport du 3H-FGF21 et du 3H-IGFBP2 n’est pas modifié par la neuropathologie MA dans le modèle murin 3xTg-AD. La coperfusion de l’IGFBP2 avec l’antagoniste du récepteur LRP1, (LRPAP1-RAP) ou d’IGFBP2 recombinant réduit significativement le transport de respectivement -64,7% et -58%.
CONCLUSION : Ces données suggèrent que le transport de FGF21 et l’IGFBP2 est saturable. Le transport de l’IGFBP2 implique le récepteur LRP1. Il faudra dans le futur, identifier les transporteurs d’entrée afin de mieux comprendre les mécanismes d’action de FGF21 et d’IGFBP2 au sein du cerveau.

Soumis par / Submitted by: Linhares, Sabrine

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #88

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

iPS Cell-Derived Assembloids: A Novel Approach to Modeling Parkinson’s Disease

LUCUMÍ-VILLEGAS, BEATRIZ 1,2; Obergasteiger, Julia 1,2; Valerie Clavet-Fournier 1,
Flavie Lavoie Cardinal 1,2; Durcan, Thomas 3; Hussein, Samer 4,5; and Martin Lévesque 1,2.

1 CERVO Brain Research Center (2601 Chemin de la Canardière, Quebec, QC, G1J 2G3, Canada).
2 Department of psychiatry and neurosciences, Université Laval, Québec, QC, Canada.
3 The Neuro, Montreal Neurological Institute (3801, Rue University, Montréal, QC, Canada).
4 Centre de recherche du CHU de Québec (9, rue McMahon 2779, Quebec, QC, G1R 3S3, Canada)
5 Department of molecular biology, medical biochemistry and pathology, Université Laval, Québec, QC, Canada

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the aggregation of alpha-synuclein (aSyn) and the degeneration of dopaminergic neurons in the substantia nigra of the midbrain, which is central to the nigrostriatal pathway that regulates motor function. In the absence of a cure, PD research often is challenged by the lack of an ideal disease model that faithfully recapitulates the intricate cellular and organotypic dynamics involved. This study aims to develop an innovative in vitro PD model consisting of a midbrain-striatal assembloid designed to mimic the synaptic connections intrinsic to the nigrostriatal pathway and key synucleinopathy manifestations. Assembloids are three-dimensional structures derived from human stem cells that combine region-specific organoids to simulate complex neuronal networks. Here, human midbrain organoids (hMOs) and human striatal organoids (hSOs) were cultured from induced pluripotent stem cells and their identity confirmed by immunofluorescence staining for midbrain dopaminergic markers (TH, FOXA2) and striatal markers (DARPP32). After 50 days of maturation, these organoids were fused together. To facilitate the tracking of projections across regions, the organoids were pre-labeled with fluorescent proteins prior to fusion, by using AAV. In addition, to mimic the spread of synucleinopathy, a mutant hSO was treated with preformed fibrils of aSyn and subsequently fused with a control hMO. Preliminary observations suggest a progressive increase in synucleinopathy markers over time. Ultimately, this project aims to develop a human-centered model that will facilitate the development and evaluation of novel neuroprotective interventions designed for Parkinson’s disease.

Soumis par / Submitted by: Lucumí Villegas, Beatriz ELena

Affiliation: Centre de recherche CERVO

Résumé/Abstract #89

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Dickkopf-1 represses recovery after stroke by deregulating neurovascular and neuroimmune responses

ROMAIN MENET1,2, Maxime Bernard1,2, Sarah Lecordier1,2, Esther Trudel1,2, Félix Distéfano-Gagné1,3, Josée Seigneur1,2, Anne-Sophie Allain1,2, Daniel Manrique-Castano1,2, Natija Aldib1,2, Yacine Haili1,2, Frédéric Bretzner1,2, David Gosselin1,3, and Ayman ElAli1,2*

1Neuroscience Axis, Research Center of CHU de Québec (CRCHUQ)-Université Laval; 2Department of Psychiatry and Neuroscience, 3Université Laval; Department of Molecular Medicine, Université Laval; Québec, QC, Canada

Introduction
Ischemic stroke constitutes a major cause of death and disability. We have previously demonstrated that stroke deregulates the canonical Wnt pathway activity, which plays key roles in regulating neurovascular functions. Interestingly, the systemic level of the major inhibitor of the canonical Wnt pathway, dickkopf-1 (DKK1), is elevated in stroke patients and correlating with poor neurological outcomes. Yet, DKK1’s implication in stroke pathobiology and therapy remains unknown.

Methods and Objectives
Our study aims to elucidate the role of DKK1 after stroke. For this purpose, we used wild-type and iDKK1 mice to allow temporal induction of DKK1 subjected to ischemic stroke via middle cerebral artery occlusion (MCAo). Furthermore, pharmacological approaches were used to neutralize DKK1’s biological activity as new therapeutic interventions to stimulate brain repair and recovery.

Results

Early DKK1 induction exacerbated infarct and oedema sizes as well as aggravated motor deficits after stroke. DKK1 induction increased neuronal degeneration and prevented neurogenesis, neuronal maturation and impaired neuronal activity. These changes were accompanied with an impaired cerebral blood flow and a dysregulated neuroinflammatory responses as well as glial scar organization. In addition, post-stroke induction of DKK1 attenuated long-term restoratives processes and motor recovery. Using RNA-seq, we found that transcriptomic genes signature was closely associated with an unresolved chronic neuroinflammation at the lesion site, while causing anxiety-like behavior. Interesting, in our experiments, we found that DKK1 was absent under physiological condition and the elevated expression of DKK1 in the lesion brain provided by infiltrated immune cells. Finally, pharmacological neutralization of DKK1’s biological activity using WAY262611 improved structural and functional recovery after stroke.

Conclusion
These findings indicate that DKK1 plays a central role in stroke pathobiology and its neutralization constitutes a clinically relevant approach to promote post-stroke neurovascular repair after stroke.

Soumis par / Submitted by: Menet, Romain

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #90

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Altered firing output of VIP interneurons and early dysfunctions in CA1 hippocampal circuits in the 3xTg mouse model of Alzheimer’s disease

MICHAUD FÉLIX*, Francavilla Ruggiero1,2,3*, Topolnik Dimitry1,2, Iloun Parisa1,2, Tamboli Suhel1,2, Calon Frederic2,4, Topolnik Lisa1,2

1Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, QC, Canada
2Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, QC, Canada
3CHU Sainte-Justine Research Center, Université de Montréal,Montreal, QC, Canada; Department of Neurosciences, Université de Montréal, Montreal,QC, Canada
4Faculty of Pharmacy, Laval University, Québec, QC, Canada.
* These authors contributed equally to this work.

Alzheimer’s disease (AD) leads to progressive memory decline, and alterations in hippocampal function are among the earliest pathological features observed in human and animal studies. GABAergic interneurons (INs) within the hippocampus coordinate network activity, among which type 3 interneuron-specific (I-S3) cells expressing vasoactive intestinal polypeptide and calretinin play a crucial role. These cells provide primarily disinhibition to principal excitatory cells (PCs) in the hippocampal CA1 region, regulating incoming inputs and memory formation. However, it remains unclear whether AD pathology induces changes in the activity of I-S3 cells, impacting the hippocampal network motifs. Here, using young adult 3xTg-AD mice, we found that while the density and morphology of IS-3 cells remain unaffected, there were significant changes in their firing output. Specifically, I-S3 cells displayed elongated action potentials and decreased firing rates, which was associated with a reduced inhibition of CA1 INs and their higher recruitment during spatial decision-making and object exploration tasks. Furthermore, the activation of CA1 PCs was also impacted, signifying early disruptions in CA1 network functionality. These findings suggest that altered firing patterns of I-S3 cells might initiate early-stage dysfunction in hippocampal CA1 circuits, potentially influencing the progression of AD pathology.

Soumis par / Submitted by: Michaud, Félix

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #91

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Regenerating dopaminergic neural circuits in Parkinson’s disease through transplantation of super-resistant human neurons

MORIN BÉATRICE 1 ; Castonguay Anne-Marie 1 ; Obergasteiger Julia 1 ; Cardoso Tiago 1 ; Watters Valérie 2, Gravel Claude 1; Hussein Samer 2; Durcan Thomas 3; Lévesque Martin 1
1 CERVO Brain Research Centre, 2601, chemin de la Canardière, Québec, QC, Canada
2 St. Patrick Research Group in Basic Oncology, Oncology Division of CHU de Québec-Université Laval Research Center, 9, Rue McMahon, Québec, QC, Canada
3 The Neuro – Montreal Neurological Institute, 3801, Rue University, Montréal, QC, Canada

PD is a chronic neurodegenerative disease characterized by the extensive loss of dopamine (DA) neurons in the substantia nigra pars compacta through the accumulation of intraneuronal Lewy bodies containing misfolded fibrillar alpha-synuclein (aSyn). These aggregates are toxic and can spread the pathology to neighboring cells, contributing to disease progression. Neuroprotective therapy based on mini antibodies (scFv) is a promising treatment for the early stage of the disease. For more advanced PD patients, cell replacement therapy is an attractive option to restore dopaminergic innervation. Although recent advances facilitate cell replacement therapy for PD, there are still hurdles to overcome. Analysis of post-mortem brains from PD patients revealed that the grafted neurons acquire aSyn pathology, thus limiting their efficacy and survival, especially in the long term. Our main objective is to develop strategies to promote the survival of transplanted DA neurons to efficiently restore DA deficiencies. Here, we tested the efficacy of secreted scFvs against aSyn to protect human iPSC-derived neurons from the spread of aSyn pathology. To control the production of our scFvs, we used the TeT-ON system which allows the production of scFvs in the presence of doxycycline. To model PD, we used unilateral midbrain injection of aSyn preformed fibrils. Subsequently, we performed the transplantation of DA neuron progenitors into mice and induced scFv transcription by administering doxycycline in their drinking water. Our preliminary data suggest that our scFvs can protect the graft from aSyn pathology. We believe that this neuro-regenerative approach will lead to a significant advance in cell replacement therapies for PD.

Soumis par / Submitted by: Morin, Béatrice

Affiliation: Centre de recherche CERVO

Résumé/Abstract #92

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Retinal changes detected by ERG and pupillometry in parkinsonian monkeys

MUNRO, JONATHAN
Parham, Elahe
Lavigne, Andrée-Anne
Côté, Daniel
Hébert, Marc
Parent, Martin
Centre de recherche CERVO

Diagnosis of Parkinson’s disease (PD) is currently made following clinical observation of motor symptoms. By the time these symptoms manifest, around 50% of dopamine neurons are lost in the substantia nigra pars compacta (SNc), limiting the possibility of implementing potential neuroprotective or neurorestorative treatments that could delay the progression of the disease. Non-motor symptoms, such as vision problems, occur much earlier along the progression of the disease. If altered functioning of the retina causes these vision problems, various techniques could be implemented to detect retinal changes, therefore providing early biomarkers for PD. The aim of this project is to determine potential early biomarkers for PD via the retina by using electroretinography (ERG) and pupillometry. In-vivo measurements were performed on 4 non-human primates (NHP), before and after they were rendered parkinsonian by administration of 1-méthyl-4-phényl- 1,2,3,6-tetrahydropyridine (MPTP), a neurotoxin that induces degeneration of dopamine neurons. Post-mortem retinal analyses were compared against the retina of 4 control NHPs. ERG results showed reduced a-wave amplitudes with slightly increased b-wave amplitudes in both photopic and scotopic conditions. Pupillometry analysis showed a consistently greater increase in pupil diameter during the post flash period. Post-mortem measurement of retinal layers found a significant thinning of the outer nuclear layer. These results indicate that MPTP caused changes to the retina detectable by ERG and pupillometry recording techniques and that these changes could be attributed to the observed retinal thinning. As MPTP is a model of PD, these results provide evidence for potential retinal biomarkers that could be used as an earlier or more accurate means of diagnosing PD.

Soumis par / Submitted by: Munro, Jonathan

Affiliation: Centre de recherche CERVO

Résumé/Abstract #93

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

The neuroprotective potential of Flcn knockout in Parkinson’s disease

OBERGASTEIGER JULIA 1, Ferguson Owen 1, Bilodeau Anthony 1, Durcan Thomas 2, Lavoie-Cardinal Flavie 1, Metzakopian Emmanouil 3, Levesque Martin 1
1 Cervo Brain Research Center, Department of Psychiatry and Neurosciences, Faculty of Medicine, Université Laval, 2601 Chemin de la Canardiere, Quebec, Canada;
2 Montreal Neurological Institute, Department of Neurology and Neurosurgery, Montreal, Canada;
3 UK Dementia Research Institute, Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK;

Parkinson’s disease (PD) is the second most common neurodegenerative disorder and presents with various motor and non-motor symptoms in people affected by the disease. One of the main hallmarks is the loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc). The second hallmark is the intraneuronal accumulation of alpha-synuclein, called Lewy bodies. No cure is available for PD until today and current treatments only alleviate the symptoms of the disease. Therefore, there is an unmet need to provide new therapeutic targets. We performed a CRISPR-based, genome-wide screen to identify new target genes rescuing the degeneration of DA neurons. We identified several new targets and one of them is the Flcn gene. Flcn is implicated in the mTOR pathway, able to regulate autophagy and interacts with several Rab GTPases involved in endocytic trafficking. Furthermore, Flcn was shown to regulate mitochondrial biogenesis. Importantly, when DA neurons are exposed to oxidative stress, Flcn knockout (KO) increases their viability in vitro. To understand the physiological role of Flcn in DA neurons and validate its neuroprotective effect, we knocked out Flcn in mouse dopamine neurons of the SNc. To model PD, we used AAV-mediated expression of human alpha-synuclein (aSyn) in the SNc. After 16 weeks we performed locomotor assessment and histological analysis of the brain. Flcn KO in SNc dopamine neurons ameliorates the motor deficits induced by aSyn overexpression and it rescues the loss of dopaminergic neurons in the midbrain and their terminals in the striatum. Most importantly, Flcn KO also reduces the levels of phosphorylated aSyn in the SNc. In parallel, we use iPSC-derived DA neurons as a model of human PD in vitro, specifically iPSCs derived from a patient with the triplication of the SNCA gene (3xSNCA), coding for aSyn, a cell line harbouring the A53T-SNCA mutation and the respective isogenic controls. FLCN inactivation leads to a translocation of the transcription factor EB (TFEB) into the nucleus, where it induces the transcription of genes related to the autophagy-lysosome pathway, which finally has an impact on aSyn accumulation. In this study, we used an unbiased screening method to identify a new neuroprotective target for PD. Following target validation, we will identify drugs capable of modulating Flcn expression and test their efficacy to modify disease onset and/or progression.

Soumis par / Submitted by: Obergasteiger, Julia

Affiliation: Centre de recherche CERVO

Résumé/Abstract #94

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

L’haplo-insuffisance en neurofibromine de fibroblastes dermiques altère la sécrétion de matrice extracellulaire dans un modèle de la neurofibromatose de type I

PAQUET, ALEXANDRE(1,2), Roy, Vincent(1,2), Gouhier, Juliette(3,4), Joly-Beauparlant Charles(5), T. Khuong, Hélène(2), Bordeleau, François(3,4), Droit, Arnaud (6), Dupré, Nicolas(2,7,8) et Gros-Louis, François(1,2)

1. Département de chirurgie, Faculté de médecine, Université Laval, Québec, QC, Canada
2. Axe de médecine régénératrice, Centre de recherche du CHU de Québec, Université Laval, Québec, QC, Canada
3. Axe d’oncologie, Centre de recherche du CHU de Québec, Université Laval, Québec, QC, Canada
4. Département de biologie moléculaire, de biochimie médicale et de pathologie, Université Laval, Québec, QC, Canada
5. Centre de génomique, Centre de recherche du CHU de Québec, Université Laval, Québec, QC, Canada
6. Département de Médecine Moléculaire, Faculté de Médecine, Centre Hospitalier Universitaire de Québec Research Center, Université Laval, Québec, QC, Canada
7. Département de sciences neurologiques; Faculté de médecine, Université Laval, Québec, QC, Canada
8. Axe de neurosciences, Centre de recherche du CHU de Québec, Université Laval, Québec, QC, Canada

Problématique: La neurofibromatose de type 1 (NF1) est une affection génétique rare résultant de mutations dans le gène de la neurofibromine (NF1). Elle est caractérisée par diverses manifestations cliniques, dont la formation de tumeurs appelées neurofibromes cutanés. La morphogénèse de ces neurofibromes reste encore incomprise à ce jour et aucun traitement efficace et personnalisé de la neurofibromatose n’a encore été développé. Nous avons récemment démontré que les fibroblastes dermiques haplo-insuffisants en neurofibromine (NF1+/-) participent activement à la modification du microenvironnement tumoral. Ainsi, l’hypothèse de la présente étude est que l’étude du microenvironnement sécrété par les fibroblastes dermiques NF1+/- cultivés en 3D par génie tissulaire permettra de caractériser les évènements moléculaires sous-jacents au développement des neurofibromes cutanés. L’objectif principal du projet consiste à caractériser la matrice extracellulaire produite par des fibroblastes dermiques de patients afin d’identifier les mécanismes impliqués dans l’établissement des neurofibromes.

Méthodes: Des peaux reconstruites par génie tissulaire ont été générées par la méthode d’auto-assemblage avec des fibroblastes de patients NF1 et d’individus sains (contrôles). L’organisation et l’abondance des fibres de collagène dans les tissus ont été évaluées par microscopie à lumière polarisée. L’expression des gènes et des protéines a été évaluée par séquençage d’ARN et par spectrométrie de masse, respectivement. Des analyses bio-informatiques ont ensuite été menées sur les données.

Résultats: La microscopie à lumière polarisée a révélé une surabondance et une désorganisation des fibres de collagène dans les feuillets de fibroblastes NF1+/-. Les analyses transcriptomiques suggèrent que de multiples gènes impliqués dans la sécrétion et l’organisation de la matrice extracellulaire, la migration cellulaire et la prolifération sont significativement surexprimés par les fibroblastes NF1+/-. De ce fait, l’expression de plusieurs transcrits faisant partie intégrante du matrisome est également fortement modulée.

Conclusions: Notre étude suggère que l’haploinsuffisance du gène NF1 altère fortement l’expression des gènes associés au dépôt de la matrice extracellulaire chez les fibroblastes dermiques, pouvant ainsi jouer un rôle majeur dans la modification du microenvironnement et favoriser le développement et la croissance des neurofibromes cutanés.

Soumis par / Submitted by: Paquet, Alexandre

Affiliation: CRCHU de Québec-UL, pavillon HEJ

Résumé/Abstract #95

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Longitudinal study of the neuronal effects of ALS-linked mutant FUS in mice and the therapeutic effects of NF-kB inhibition

PELAEZ, MARI CARMEN
Desmeules, Antoine
Gelon, Pauline
Glasson Bastien
Marcadet, Laetitia
Rodgers, Alicia
Phaneuf, Daniel
Pozzi, Silvia
Dutchak, Paul A.
Sephton, Chantelle F.

Background: There is mounting evidence that suggests dendritic attrition and synaptic loss are important contributors to amyotrophic lateral sclerosis (ALS). Post-mortem histological analysis of ALS patients’ brain and spinal cord tissues showed neuromorphological alterations in upper (UMNs) and lower motor neurons (LMNs). These structural changes are proposed to drive cognitive and motor impairments in ALS. We previously demonstrated that global expression of the ALS-linked FUSR521G variant in mice caused dendritic attrition and spine loss in motor-neurons (MNs), coinciding with cognitive and motor impairments. However, many questions remain concerning the contribution of neuromorphological alterations on the behavioral impairments observed in our model; the influence of cell-autonomous versus non-cell autonomous mechanisms that contribute to these changes; and whether therapies that stabilize dendritic structures can attenuate ALS-associated phenotypes.

Objectives: In this study, we aimed to generate a neuron-specific mouse model expressing the FUSR521G variant to determine the effects of FUSR521G expression on neuromorphology and behavior phenotypes. Moreover, we aimed to assess the therapeutic potential of an NFkb inhibitor, IMS-088, on attenuating these changes in this mouse model.

Methods and results: A neuron-specific mouse model expressing the FUSR521G variant was generated by crossing the CAG-Z-FUSR521G-IRES-EGFP mice with Syn1Cre mice, hereafter referred to as FUSR521G/Syn1. FUSR521G/Syn1 and littermate control mice were analyzed for cognitive and motor function at different timepoints. In parallel, the dendritic branching and spine density of MNs were analyzed. We found that 1-month-old FUSR521G/Syn1 mice presented dendritic attrition without loss of spine density in their UMNs; corresponding with cognitive impairments in these mice. Importantly, we observed a progressive loss of spine density of UMNs, a loss of dendritic branching of LMNs and glial activation in 6-month-old mice, which preceded the motor impairments observed in 8-month-old mice. We then assessed the therapeutic potential of IMS-088 on attenuating dendritic branching and synaptic loss in FUSR521G/Syn1 mice. We found that IMS-088 treatment led to a corresponding decrease in glial activation, enhancement of dendritic structures and synapses along with cognitive and motor improvement.

Conclusion: Our study shows that dendritic and spine defects that occur in MNs are due to the intrinsic mechanisms caused by FUSR521G. Moreover, these changes are progressive and sufficient to cause behavioral impairments. Importantly, treatment of FUSR521G/Syn1 mice with IMS-088 greatly improves the neuronal morphology and synaptic structures in these mice. These findings indicate that therapeutic strategies that stabilize dendritic structures of MNs should be considered in the treatment of ALS.

Soumis par / Submitted by: Pelaez, Mari Carmen

Affiliation: Centre de recherche CERVO

Résumé/Abstract #96

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Optimization and characterization of a light inducible protein aggregation system to study TDP-43 proteinopathy in the context of Amyotrophic Lateral Sclerosis.

SHANNA PIGEYRE 1,2, Maxime Teixeira 2,3, Morgan Bérard 1, Plateforme d’outils moléculaire 1, Abid Oueslati 2,3 and Silvia Pozzi 1,4
1- Centre de recherche CERVO, 2601, Av. de la Canardière, Québec, QC, G1J 2G3, Canada
2- Centre de rechercher CHUL, 2705 Bd Laurier, Québec, QC G1V 4G2
3- Département de médecine moléculaire, Université Laval
4- Département de Psychiatrie et Neuroscience, Université Laval

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease that causes degeneration of the motor neurons involved in controlling muscle movement. Several observations have highlighted the possibility that certain pathological events start in muscle cells, or at the synapse between motor neurons and muscles (neuromuscular junction, NMJ), and spread to motor neurons, inducing their death. These observations support the so-called « dying-back » hypothesis of ALS.
In ALS, the TDP-43 protein (TAR-DNA-Binding-Protein) delocalizes from the nucleus to the cytoplasm, forming toxic aggregates in the latter that induce neuronal death. This event, known as TDP-43 proteinopathy, is well established in motor neurons. Interestingly, TDP-43 aggregates are also observed in muscle cells from ALS patients, but their consequences in these cells are still unknown. We also know that neurons can propagate TDP-43 proteinopathy through exosomes to other cell types, but we do not know whether muscle cells are able to propagate TDP-43 to motor neurons.
Our research hypothesis is therefore that muscle cells play a role in the pathology, by transmitting the TDP-43 protein to neurons at the NMJ, using exosomes.
Dr Oueslati’s lab developed an optogenetic system, called Light Inducible Protein Aggregation (LIPA), that induces the aggregation of alpha-synuclein as observed in Lewy body of Parkinson’s disease.
The aim of this project is to create a LIPA-TDP-43 system to be implemented in muscles cells to study the consequences of TDP-43 proteinopathy in the peripheral nervous system.
Here we show that we successfully generated a LIPA-TDP-43-WT construct that was first implemented in Hek293 cells by transient transfection. Cells were then stimulated with blue light (0,8mW) for different time points. By immunofluorescence we were able to see a time-dependent mislocalization of TDP-43 from nucleus to cytoplasm and the formation of aggregate-like particles of TDP-43 in the cytoplasm. We also demonstrated that, after light induction, LIPA-TDP43 can be found in the exosomes fraction present in the cellular medium.
We are presently implementing this system in a mouse muscular cell line (C2C12). This model will help us to study the consequences of TDP-43 proteinopathy in the peripheral nervous system and will be used to identify therapeutic approaches that can reduce TDP-43 proteinopathy in a context of ALS.

Soumis par / Submitted by: Pigeyre, Shanna

Affiliation: Centre de recherche CERVO

Résumé/Abstract #97

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Targeting TDP-43 with a full-length antibody mitigates pathology induced by infusion of CSF from ALS patients

POULIN-BRIÈRE, AMÉLIE; Pozzi, Silvia; Julien, Jean-Pierre. Centre de recherche CERVO

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the death of motoneurons (MN) for which there is currently no cure. The loss of MN leads to progressive paralysis causing death by respiratory failure 2 to 5 years after the diagnosis. Genetic mutations are responsible for 10% of ALS cases, known as familial ALS, while the exact causes and mechanisms are still unknown for 90% of ALS cases, known as sporadic ALS (sALS). Abnormal cytoplasmic aggregates of TAR DNA-binding protein 43 (TDP-43) are a pathological hallmark of ALS, in both familial and sporadic cases. This TDP-43 proteinopathy leads to loss of normal function and gain of toxic function contributing to neuronal death (Hergesheimer et al., 2019). Moreover, various studies suggest that TDP-43 has prion-like properties, transmitting the pathology to healthy neighbouring cells (Nonaka, 2020). The clearance of TDP-43 cytoplasmic aggregates could thus represent promising therapeutic strategies.
Recently, our group (Pozzi et al.,2019; 2020) reported that an immunotherapy using a full lenght antibody (called E6 Ab) directed against the RRM1 (RNA Recognition Motif 1) domain of TDP-43 protein mitigated TDP-43 pathology in transgenic mice expressing TDP-43 mutants linked to familial ALS. In 2015, Smith et al. suggested that the cerebrospinal fluid (CSF) could be involved in the progression of the disease by carrying toxic factors to other regions of the central nervous system, such as pathological TDP-43. In line with this hypothesis, our group developed a new mouse model of sALS based on intracerebroventricular (i.c.v.) infusion of CSF from sporadic ALS patients in mice expressing the human wild type TDP-43 protein (hTDP-43WT) (Mishra et al., 2020).
Here, we tested the effects of E6 Ab in this new mouse model of sALS. Using mini-osmotic pumps, 8-month-old hTDP-43WT mice were infused i.c.v with CSF for two weeks. Intrathecal (IT) injection of E6 Ab ameliorated motor performance and reduced TDP-43 proteinopathy in the lumbar spinal cord. Remarkably, the i.c.v. co-infusion of E6 Ab with ALS-CSF mitigated TDP-43 pathology in the brain motor cortex and rescued motor and cognitive deficits in this mouse model of sALS. Recovery of levels and nuclear localisation of TDP-43 led to restoration of neurofilament protein levels and distribution in both IT and i.c.v treatments. Moreover, preliminary results highlight an alleviation of neuromuscular junction denervation in mice treated with E6 Ab. These results suggest that infusion of antibodies targeting TDP-43 is an approach that should be considered for treatment of ALS and other neurodegenerative disorders with TDP-43 pathology. Our team is now testing whether the depletion of TDP-43 in CSF may reduce neuronal toxicity and neuroinflammation in cultured cells.

Soumis par / Submitted by: Poulin-Brière, Amélie

Affiliation: Centre de recherche CERVO

Résumé/Abstract #98

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

The effects of trehalose on the enteric and central nervous systems in a transgenic mouse model of Parkinson’s disease

Solène Pradeloux, Katherine Coulombe, Amandine Isenbrandt, Alexandre Jules Kennang Ouamba, Frédéric Calon, Denis Roy, Denis Soulet.

Parkinson’s disease (PD) is a neurodegenerative disorder affecting the dopaminergic neurons in the nigrostriatal region of the brain and causes neuronal inclusions mainly composed of the protein alpha-synuclein (αSYN). The disease manifests as motor symptoms, which are often preceded by non-motor symptoms such as gut microbiota disturbances and constipation. These could be related to damage to the enteric nervous system.
Trehalose is a sugar found in fungi that has shown neuroprotective effects in various models of neurodegenerative diseases. However, its mechanism of action is still unclear. Therefore, we aim to validate the neuroprotective potential of trehalose through its intestinal action.
We used transgenic mice that overexpress human αSYN as a model of PD. We treated them with drinking water or water containing trehalose, maltose or sucrose (2%, w/vol) for seven months. We performed behavioral tests and collected feces to analyse fatty acids and microbiota. We also carried out postmortem histopathological analyses of the brain and intestine.
The preliminary results show that transgenic mice exhibit hyperactivity, stress, anxiety, constipation. They also show a decrease in striatal tyrosine hydroxylase (an enzyme involved in dopamine synthesis), which is prevented by trehalose treatment. The gut microbiota analysis reveals a significant difference in microbial diversity between the two genotypes, and that trehalose affects the composition of the microbiota.
In conclusion, trehalose has promising neuroprotective effects that could be mediated by the microbiota. This work has a significant impact for PD patients, as it could lead to a nutraceutical clinical study on trehalose in the future.

Soumis par / Submitted by: Pradeloux, Solène

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #99

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

La sensibilité élevée de la protéine tau à la température induit rapidement des artefacts de phosphorylation chez les animaux et en culture cellulaire.

ROCABOY EMMA (1), Canet Geoffrey (1, 2), Diego-Diaz Sofia (1), Laliberté Francis (2), Boscher Emmanuelle (1, 2), Fereydouni-Forouzandeh Parissa (1), Guisle Isabelle (1, 2), Hébert Sébastien S. (1, 2), Planel Emmanuel (1, 2).

(1) Université Laval, Faculté de Médecine, Département de Psychiatrie et Neurosciences, Québec, QC, Canada
(2) Centre de Recherche du CHU de Québec, Axe Neurosciences, Québec, QC, Canada

L’hyperphosphorylation et l’agrégation de la protéine tau sont des marqueurs pathologiques de la maladie d’Alzheimer (MA). L’analyse de la phosphorylation de tau est donc couramment réalisée en laboratoire. Cependant, l’influence de facteurs tels que la température est souvent sous-estimée, ce qui peut conduire à des résultats artéfactuels. En effet, les mécanismes biologiques susceptibles de modifier la phosphorylation de tau sont dynamiques et sensibles aux fluctuations de température.

Dans cette étude, nous avons cherché à mimer certaines conditions expérimentales conduisant à une modification de la température et pouvant affecter la phosphorylation de tau de manière artefactuelle. Notre objectif était de souligner l’importance de considérer et de contrôler la température dans les protocoles expérimentaux, afin d’améliorer la reproductibilité des résultats.

Nous avons analysé la cinétique de phosphorylation de tau dans deux lignées neuronales dont les boîtes ont été laissées à température ambiante avant d’en extraire les protéines. Nous avons observé que la phosphorylation de tau augmente rapidement seulement quelques secondes après leur retrait de l’incubateur. Cette phosphorylation artéfactuelle peut être évitée en plaçant les cellules sur glace avant d’effectuer l’extraction des protéines.

Comme l’anesthésie est couramment utilisée lors de chirurgie et euthanasie d’animaux de laboratoire, nous avons évalué l’impact de l’hypothermie induite par l’isoflurane sur l’hyperphosphorylation de tau chez des souris. Nous avons montré que seulement quelques secondes d’anesthésie étaient suffisantes pour induire une hypothermie associée à une hyperphosphorylation de tau sur de nombreux épitopes dans le cortex et l’hippocampe des animaux.

En conclusion, ces résultats soulignent l’importance de limiter les variations de température lors de la conception de protocoles expérimentaux in vivo et in vitro, en particulier lorsque ceux-ci impliquent l’étude de la protéine tau. Pour garantir des résultats précis, nous recommandons d’euthanasier les animaux sans anesthésie préalable, et de placer rapidement les cellules sur la glace dès leur retrait de l’incubateur. En contrôlant les fluctuations de température, la fiabilité et la validité des recherches associées à l’analyse protéine tau seront améliorées.

Soumis par / Submitted by: Rocaboy, Emma

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #100

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Glutamate co-transmission by serotonin neurons of the dorsal raphe nucleus contributes to L-Dopa-induced dyskinesia.

SAIDI LYDIA, Rioux Véronique, Wallman Marie-Josée, Pozzi Silvia, Lévesque Martin, Proulx Christophe, Parent Martin
CERVO Brain Research Center, Université Laval, QC

OBJECTIVE: Parkinson’s disease is characterized by the progressive loss of midbrain dopamine neurons that innervate the striatum. The dopamine precursor L-3,4-dihydroxyphenylalanine (L-Dopa) is the most effective pharmacotherapy but its chronic use is hampered by side effects such as abnormal involuntary movements (AIMs), also termed L-Dopa-induced dyskinesia (LID). Previous studies have shown the crucial role of serotonin (5-HT) neurons in the conversion of exogenous L-Dopa into dopamine, and in LID expression. Here, we specifically addressed the functional role of glutamate co-transmission by 5-HT neurons of the dorsal raphe nucleus (DRN) in the regulation of motor behavior and in LID expression. METHODS: In 6-hydroxydopamine-intoxicated mice, a chemogenetic approach was first used to alter the neuronal activity of DRN 5-HT neurons while administering L-Dopa in order to specifically address the role of these neurons on LID expression. Using the same mouse model of Parkinson’s disease, we then used CRIPSR-Cas9 technology and virus injections to knock-out or overexpress the atypical vesicular glutamate transporter 3 (VGluT3) in 5-HT neurons of the DRN. These mice were then treated with L-Dopa to induce AIMs. RESULTS: Compared to control conditions, AIMs severity was increased when 5-HT neurons of the DRN were acutely activated by hM3Dq-DREADD, and reduced when DRN 5-HT neurons were inhibited by hM4Di-DREADD. Our CRIPSR-Cas9 manipulations led to exacerbated AIMs in dopamine-lesioned VGluT3-conditional knock-out mice that were treated with a non-dyskinetic dose of L-Dopa (1mg/kg), compared to controls and to transgenic mice overexpressing VGluT3. At higher doses of L-Dopa (3, 6, 12 mg/kg), mice overexpressing VGluT3 showed more severe orofacial AIMs. CONCLUSIONS: Glutamate that is co-released by 5-HT neurons of the DRN is involved in the expression of LID.

Soumis par / Submitted by: SAIDI, Lydia

Affiliation: Centre de recherche CERVO

Résumé/Abstract #101

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Caractérisation du transport des corps cétoniques (D-β-hydroxybutyrate, BHB) à travers la barrière hémato-encéphalique dans un modèle de la maladie d’Alzheimer

Dominique Seguin 1,2,3, Manon Leclerc 1,2,3, Sabrine Linhares 1,2,3, Vincent Emond2,3, Frédéric Calon 1,2,3.
1Faculté de Pharmacie, Université Laval, Québec, Québec, Canada.

2Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, Québec, Canada

3Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, Québec, Canada

PROBLÉMATIQUE : Le BHB est un corps cétonique pouvant être utilisé par le cerveau comme source d’énergie alternative au glucose. Dans le contexte de la maladie d’Alzheimer (MA), l’assimilation et l’utilisation du glucose devient défectueuse générant un déficit énergétique au cerveau. Des interventions cétogènes sont en cours d’expérimentation clinique.
OBJECTIF : Les mécanismes de transport du BHB à travers la barrière hémato-encéphalique (BHE) et le rôle des transporteurs monocarboxylates (MCT) reste inconnus. MÉTHODOLOGIE : La perfusion cérébrale intracarotidienne a été utilisée pour quantifier et caractériser le transport du 3H-BHB à travers la BHE de souris non transgéniques et de souris 3xTg-AD (modélisant la neuropathologie de la MA). Un régime riche en lipides (HFD) a été utilisé pour induire l’obésité et des troubles métaboliques. RÉSULTATS : Tous d’abord, nous avons démontré que le 3H-BHB traverse la BHE de la souris avec un coefficient de transport cérébral (Clup) d’environ 1 µl.g-1.s-1, similaire à celui du D-glucose. La compétition avec du BHB non marqué (x200, x2000 et x20 000) n’a pas réduit le Clup, ce qui est cohérent avec un transport non saturable. Cependant, le blocage de son transporteur putatif MCT1 avec la coperfusion d’AZD3965 a entraîné une diminution significative du Clup (-17 %), suggérant que même si la majeure partie du 3H-BHB diffuse librement à travers la BHE, il peut être optimisé par un mécanisme de transport plus spécifique. La captation du 3H-BHB par le cerveau est restée similaire chez les souris 3xTg-AD par rapport aux souris non transgéniques, indépendamment de la diète et l’âge des souris (14 et 21 mois). CONCLUSION : Nos résultats indiquent que (i) le taux de transport du BHB au cerveau est similaire à celle du glucose mais par un mécanisme non saturable, (ii) partiellement dépendante du transporteur MCT1 et (iii) non affectée par le vieillissement, la neuropathologie de la MA ou la consommation de HFD.

Soumis par / Submitted by: Seguin, Dominique

Affiliation: CRCHU de Québec-UL, pavillon CHUL

Résumé/Abstract #102

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Novel non-invasive retinal and microbial biomarkers for the early diagnosis of Parkinson’s disease

SOTO LINAN, VICTORIA DE LOS ANGELES (1,2), Gora, C (1,2), Peralta, M (1), Guevara Agudelo, FA (2,4), Dupré, N (2,3), Hébert, M (1,2), Raymond, F (2,4), and Lévesque, M (1,2)

1 CERVO Brain Research Center, Quebec, Canada
2 Université Laval, Quebec, Canada
3 CHU of Quebec, Quebec, Canada
4 INAF Quebec, Canada

Parkinson’s (PD) diagnosis primarily occurs after severe neurodegeneration, despite early non-motor symptomatology being present decades prior. With the need for efficient biomarkers, we aimed to validate non-invasive techniques — electroretinography (ERG) and oral microbiota — to detect emerging peripheral effects reflecting early central dysfunction.

We used two-month-old homozygous M83 mice overexpressing human A53T α-synuclein (aSyn) as a PD model (n=40). Mice of both sexes underwent behavioral testing, ERG measurements, and oral swab collection. At four months, histological analyses were performed to assess synucleinopathies and neurodegeneration. Simultaneously, early-onset idiopathic PD patients (n=17, age 63.0±8.2; disease duration 3.6±1.3) and healthy age-matched controls (n=14, age 63.1±7.6) were recruited, including both sexes. They underwent ERG testing, Salivette swabs, and unstimulated saliva collection.

Primarily, ERG analysis in mice revealed a 29.9%±0.2 and 39.2%±1 photopic b-wave amplitude reduction at two and four months, most prominent in females and indicating bipolar cell impairment. M83 mice also exhibited a 32.2%±0.2 and 23.7%±0.2 PhNR-wave amplitude reduction at two and four months, respectively. Based on retinal immunofluorescence imaging of M83 mice, ERG changes may be tied to outer retina aSyn phosphorylation. Echoing our animal model, women with Parkinson’s disease consistently presented similar impaired parameters in ERG testing. In scotopic stimulation of the pure rod and mixed rod-cone response, a 31.4%±0.6 and 32.6%±0.4 b-wave amplitude reduction was found. The oscillatory potentials isolated from scotopic testing further detected an attenuated amacrine cell output, shown by a 58.8% ±1.2 amplitude reduction. Additionally, 46.0%±0.2 and 33.5%±0.2 reduction in the PhNR b-wave and PhNR-wave amplitude of women suggested hindered retinal ganglion cells. Lastly, the analysis of both swab and saliva samples exhibited group and sex-specific familial level abundance shifts of bacteria previously identified as opportunistic pathogens and linked to PD onset and development.

Altogether, our results in mice and human cohorts suggest that in PD, retinal functional impairments and oral microbiota abundance shifts can be detected early, particularly in females. In the future, these tools may not only contribute to diagnosis establishment but also provide a wider window for therapeutic intervention and improved patient outcome.

Soumis par / Submitted by: Soto Linan, Victoria de los Angeles

Affiliation: Centre de recherche CERVO

Résumé/Abstract #103

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Effet de la stimulation transcrânienne magnétique répétée (rTMS) sur la dénomination d’actions

Spigarelli, Manon
Wilson, Maximiliano
Massé-Alarie, Hugo

Le manque du mot (i.e. anomie) est la plainte cognitive la plus importante chez la personne aînée en santé et les personnes atteintes de troubles acquis du langage. L’anomie est plus marquée pour les verbes d’action (ex. courir) que pour les objets (ex. chaussures). La stimulation magnétique transcrânienne répétitive (rTMS) est une méthode non invasive qui modifie l’activité cérébrale. Elle a montré des effets bénéfiques sur le langage, notamment en améliorant la dénomination d’objets. Cependant, peu d’études se sont concentrées sur l’effet de la rTMS sur la dénomination d’actions.
Cette recherche vise à examiner l’effet de la stimulation cérébrale par rTMS sur la capacité des adultes en santé à nommer des actions avec des vidéos. L’étude inclut 40 participants en santé, qui ont été évalués avant et après l’intervention avec des clips vidéo d’actions. Les résultats préliminaires mettent en évidence que le temps de réaction pour nommer une action était plus court après stimulation d’une zone dédiée aux actions chez des adultes en santé par rapport à une zone contrôle.
Cette recherche pourrait orienter le développement de thérapies combinant rTMS et orthophonie pour aider les personnes souffrant de troubles du langage, comme l’aphasie post-AVC à récupérer plus efficacement leur capacité verbale

Soumis par / Submitted by: SPIGARELLI, Manon

Affiliation: CIRRIS

Résumé/Abstract #104

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Les neurones cholinergiques du tronc cérébral et la maladie de Parkinson

VERVILLE, LAURIE-SHAN
chebl, maya, centre de recherche cervo
saikali, stephan, hôpital de l’enfant-jésus, chu de québec-université laval
gould, peter v., hôpital de l’enfant-jésus, chu de québec-université laval
dufresne, anne-marie, hôpital de l’enfant-jésus, chu de québec-université laval
langlois, mélanie, la cité médicale
pourcher, emmanuelle, clinique ste-anne mémoire et mouvement
ménard, caroline, centre de recherche cervo
parent, martin, centre de recherche cervo

La maladie de Parkinson (MP) est une maladie neurodégénérative caractérisée par des troubles moteurs très incapacitants ainsi que plusieurs symptômes non-moteurs. Cette affection cible principalement les ganglions de la base, un ensemble de structures nerveuses jouant un rôle crucial dans le contrôle du comportement psychomoteur. Le noyau subthalamique (NST) est une composante clé des ganglions de la base et les neurones qui le composent présentent une activité dérégulée dans la MP. L’objectif général de cette étude est de caractériser les changements neuroadaptatifs qui surviennent dans la MP et qui pourraient contribuer à l’activité dérégulée des neurones du NST. Plus particulièrement, nous avons entrepris l’étude des neurones cholinergiques du tronc cérébral qui projettent leur axone au NST. À partir de cerveaux post-mortem provenant de patients MP et des cerveaux contrôles, nous avons appliqué une approche stéréologique afin d’estimer, dans le noyau pédonculopontin compacta (PPNc) et dissipata (PPNd), ainsi que dans le noyau latérodorsal (LDTg) du tegmentum mésencéphalique, la densité des neurones cholinergiques (immunoréactifs pour l’acétylcholine transférase, ChAT) qui contiennent ou non la forme phosphorylée de la protéine α-synucléine (α-syn pSer129), une composante importante des corps de Lewy. Nos résultats préliminaires indiquent que, dans le PPNc, le PPNd et le LDTg, la densité des neurones cholinergiques mesurée dans les cerveaux MP n’est pas différente de celle retrouvée dans les cerveaux contrôles appariés. Dans les cerveaux MP, bien que la proportion de neurones ChAT+ contenant la protéine α-syn pSer129 soit similaire dans le PPNc (27%), le PPNd (19%) et le LDTg (25%), la forme agrégée de la protéine est davantage présente dans le PPNc et le LDTg. De plus, au sein du PPNd et LDTg, les corps de Lewy sont retrouvés en plus grande proportion dans les neurones non-cholinergiques. Bien que nos travaux antérieurs aient démontrés un nombre d’axones cholinergiques réduit dans le NST de patients MP, nos résultats indiquent que les corps cellulaires sont préservés. De plus, notre étude indique que les neurones non-cholinergiques situés dans ces régions du tronc cérébral sont davantage affectés par les processus pathologiques qui caractérisent la MP.

Soumis par / Submitted by: Verville, Laurie-Shan

Affiliation: Centre de recherche CERVO

Résumé/Abstract #105

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Music Perception in Seniors: Exploring the Impact of Musical Experience

WHITTOM, ALEXIS, Centre de recherche CERVO, Faculté de médecine, Université Laval
Blanchette, Isabelle, Centre de recherche CERVO, École de psychologie, Université Laval
Tremblay, Pascale, Centre de recherche CERVO, Faculté de médecine, Université Laval
Sharp, Andréanne, Centre de recherche CERVO, Faculté de médecine, Université Laval

Hearing loss is highly prevalent among the elderly and significantly alters peripheral and central auditory processing, which are essential for music perception. A literature review from our lab suggests that musical activities can positively influence music perception in older adults. However, most of the studies surveyed measured neither their participants’ hearing threshold nor their musical experience. The goal of this project was to investigate the impact of musical experience, hearing loss and age and the interaction between these variables on music perception. 54 older adults aged 60 to 95 years were recruited. Following a hearing screening, they completed a musical experience survey and two tasks measuring music perception: a short version of the Montreal Battery Evaluation of Amusia (MBEA) measuring pitch and rhythm and a task measuring emotion recognition in music. A multiple regression analysis revealed a negative association between MBEA scores and hearing loss, which was moderated by musical experience (R2 = 0.514, p < 0.001). Additionally, scores for emotion recognition showed a negative association with age, but a positive association with musical experience (R2 = 0.475, p < 0.001). This suggests that between hearing loss and age, the former has a stronger negative association with MBEA performance while the latter is most strongly negatively associated with emotion recognition in music. Yet, musical experience has a protective effect on performance for both tasks, suggesting that it has a positive impact on music perception in the elderly.

Soumis par / Submitted by: Whittom, Alexis

Affiliation: Centre de recherche CERVO

Résumé/Abstract #106

Axe de recherche / Research Axis: 1. Viellissement et maladies neurodégénératives / Aging and neurodegenerative diseases

Extracting structural properties from cultured neurons using digital holography microscopy and U-Net

Authors: Zahra Yazdani1,2,3, Erik Bélanger1, Maxime Moreaud1, Jodie Llinares1, Mohamed Haouat1,2 ,Marie-Ève Crochetière1, Pierre Marquet1,2, Antoine Allard2,3, Patrick Desrosiers1,2,3
¹ CERVO Brain Research Center, ² Université Laval, 3 Centre interdisciplinaire en modélisation mathématique de l’Université Laval

Digital holographic microscopy (DHM) has significantly advanced non-invasive imaging, particularly in the study of living cells, through the provision of quantitative phase images (QPIs). Recognizing the imperative for large-scale cell analysis, crucial in fields like compound screening and neuronal network studies, we introduce an innovative computational framework. This framework combines DHM with machine learning models to accurately process DHM QPIs of living neurons in cultures, segmenting neuronal processes and cell bodies. It generates a graph model with cell bodies as vertices and potential connections as edges. We refer to this graph model as the graph fingerprint of the culture.

At the core of our approach are two U-Nets convolutional neural networks: one for cell-body segmentation and the other for neurite segmentation. We trained these U-Nets using manually segmented DHM QPIs of rat cortical neurons in culture, and subsequent numerical experiments demonstrated high predictive accuracy, with an area under the mean receiver operating characteristic curve of 0.98 for cell-body segmentation and 0.91 for neurite segmentation, indicative of nearly perfect classification. Our framework is augmented by path-finding algorithms that use binary mask images predicted by the U-Nets to identify possible paths along segmented neurites between each pair of cell bodies.

Our investigation encompasses a comprehensive array of 20 normalized graph measures, termed features, enabling the characterization of both local and global organization of the graph fingerprint. We analyzed 192 rat-derived neuronal network fingerprints, offering insights into their distinct developmental stages. We also employed principal component analysis, which allowed us to uncover patterns and relationships within the measures that might not be immediately evident in the original high-dimensional graph measures. Interestingly, we observed significant variance among measures during the early stage of development, which gradually decreased as the cell culture matured.

Moreover, employing a Random Forest Classifier, we distilled the most relevant graph features for classifying neural networks into their developmental stages, with Density and Modularity emerging as crucial features. Additionally, we conducted a thorough analysis of the correlation between the features, utilizing clustering techniques to unveil inherent similarities among them. These findings not only elucidate the developmental intricacies of neuronal networks at the microscopy level but also lay the groundwork for future studies aimed at comprehending the underlying principles of functional and structural neuronal network organization, particularly in human-induced pluripotent stem cell-derived cultures from patients with early-stage brain disorders.

Soumis par / Submitted by: Yazdani, Zahra

Affiliation: Centre de recherche CERVO