Stem cells, Disease modeling and Neuroregeneration

Team leader: 
Description: 

We are interested in studying the molecular and cellular mechanisms driving pathogenic processes in the human brain, but also to identify/validate new therapeutic targets or molecules. More specifically, we propose to develop novel approaches to better understand/treat Alzheimer’s disease on the one hand, and brain tumours on the other. To tackle such challenges, we focus on developing advanced in vitro / in cellulo models that are able to recapitulate the disease phenotypes associated to these diseases, and then exploit them to reveal the pathogenic mechanisms at stake. To this end, we use human induced pluripotent stem cells (hiPSCs) and genome editing-based strategies with CRISPR/Cas9 system. Ultimately, we anticipate that our research will lead to the generation of custom-tailored cells and models for treating and understanding brain diseases through manipulation of defined genes and pathways.

Innovative models to study human diseases are especially crucial for tissues/organs that are largely inaccessible, such as the brain. Due to the overall inaccessibility of human brain cells for laboratory research, brain diseases have largely been studied through the use of simplified cellular models and animal models. Even though large strides have been achieved in our understanding of brain diseases with such models, they also present drawbacks that limit succes when translating promising laboratory findings into the clinic. Our research aims at reducing this gap between laboratory research and translational research by developing human models based on patient-derived iPSCs, which bear the genetic information of the patients and allow differentiating and studying brain cells (e.g., neurons or astrocytes) that will present disease-relevant phenotypes. Of outmost interest, hiPSC-based models are accessible for genetic manipulation and amenable to drug development/screening/testing, which facilitates molecular and cellular studies on disease-affected human cell types and offer a unique opportunity to accelerate investigations for new therapeutic developments.

Research topics: 

The "Stem cells, Disease modeling and Neuroregeneration" team is a double edge sword research group that aims at generating pertinent modeling platforms of brain diseases to enhance our fundamental understanding as well as investigate novel therapeutic strategies.

Examining pathogenic mechanisms underlying Alzheimer’s disease

Our goal is to examine the pathogenic mechanisms underlying Alzheimer’s disease (AD) initiation/progression and investigate potential therapeutic avenues by targeting newly identified molecular candidates at play in the disease. To this end, we are using patient-specific hiPSCs presenting mutations (or specific genetic risk factors) in disease-associated genes (e.g., APP, APOE). In addition, we are also generating isogenic sets of hiPSC lines; i.e. either by inserting disease-specific mutations in a control “non-AD” genetic background or by genome editing of disease-associated genetic mutations/risk factors. From those hiPSC lines we are applying differentiation strategies in order to generate different cell types (e.g., neurons and astrocytes) and implement in vitro model systems recapitulating disease-relevant phenotypes found in AD, and then use them to reveal cellular and molecular disease mechanisms. Among the different questions we are investigating with these models, one of our major interests is to study the role of astrocytes in AD pathogenesis as we believe that the crosstalk between neurons and astrocytes is a pivotal determinant in AD through the modulation of factors at the interplay between amyloidosis and neuroinflammation. In addition, and in collaboration with Dr. Santiago Rivera’s team, we use our models to investigate in human settings new molecular targets first identified in mouse models, and evaluate whether they could represent good candidates for the development of therapeutics against AD.

Investigating gliomagenesis with human iPSCs

We previously demonstrated that hiPSCs may represent a useful tool for modeling adult gliomagenesis and Glioma tumor initiating cell (GTIC) formation (Sancho-Martinez et al., Nature Communications 2016). The strategy we developed allows for the generation of large collections of patient-specific “induced”-GTICs (iGTICs) bearing different genetic mutations. To follow up on this strategy we are pursuing the development of hiPSC-based models to study gliomagenesis (monolayer-based systems and 3D “brain organoïdes”). Combining our hiPSC-based modeling approaches together with gene-editing technologies, we are examining the role that certain mutations may have on brain cancer predisposition/malignancy and how they synergize during gliomagenesis by controlling tumorigenic mechanisms. This work is, in part, led in collaboration with Pr. Dominique Figarella-Branger’s team. We are also interested in using our in vitro model systems for the screening/testing/validation of novel anti-glioma drug candidates. Along this line, we have an ongoing collaboration with Dr. Michel khrestchatisky’s team and the Vect-Horus company in order to develop a modeling platform mimicking the neuro-glial-vascular unit, with the ultimate goal to provide a useful tool for the screening of compounds and the development of peptide vectors conjugated to newly identified drugs against glioma cells (primarily against GTICs).

Partners: 

            

Galerie

    • Bright field picture displaying a human iPSC colony derived from an Alzheimer patient

    • Human iPSC-derived astrocytes labeled for GFAP (green)

    • Human iPSC-derived neural progenitors labeled for NESTIN (red) and PAX6 (green). Cells were counterstained with Hoechst blue (blue).

    • lck-scarlett neuron

      Human iPSC-derived neurons labeled upon transfection with a Lck-mScarlet-I construct

Highligthed Publications

Open Positions

PROPOSITION SUJET DE THESE

L’Apolipoprotéine E humaine comme un modulateur de processus neuro-pathogéniques dans la maladie d’Alzheimer

 

Equipes  : Plasticité et Dégénérescence Neurales et Cellules souches, modélisation des maladies et neurorégénération

Directeur de Thèse : Santiago Rivera (DR2 CNRS)

Codirecteur : Emmanuel Nivet (CR CNRS)

Positionnement du projet

L’Apolipoprotéine E (APOE) humaine présente un polymorphisme et les porteurs du variantAPOE-ε4 ont un risque augmenté pour la maladie d’Alzheimer (MA). Ceci place l’APOE comme un déterminant cellulaire critique pour étudier la maladie et chercher à identifier, ou mieux comprendre, certains des mécanismes pathogéniques associés. L’APOE cérébrale est majoritairement d’origine gliale, permettant d’envisager d’étudier son impact pathogénique sur les cellules gliales et sur les interactions neuro-gliales. Nos résultats ont mis en évidence un rôle important de l’APOE dans la réponse inflammatoire astrocytaire et suggèrent que la glie joue aussi un rôle dans le contrôle de mécanismes pathologiques au sein des neurones via l’APOE.

Objectifs

L’objectif est d’investiguer l’APOE humaine comme un régulateur fonctionnel capable de moduler des mécanismes pouvant être altérés précocement dans la MA. Trois sous-objectifs sont définis :

1) Etudier l’impact d’APOE et son polymorphisme sur la réactivité gliale et autres fonctions gliales importantes dans la MA ;

2) Déterminer l’impact d’APOE et son polymorphisme dans la communication neuro-gliale à travers ses conséquences sur l’amyloïdogenèse et les mécanismes associés;

3) Evaluer l’impact fonctionnel d’une modulation d’APOE.

Méthodes

Des cellules astrocytaires, microgliales et neuronales seront différenciées à partir de cellules iPS humaines modifiées par CRISPR-Cas9 pour présenter différents statuts génotypiques d’APOE. L’objectif #1 impliquera des analyses génomiques, secretomiques et des tests in cellulo pour déterminer des corrélations entre l’état de réactivité des cellules gliales, leur statut génotypique et certaines altérations fonctionnelles comme une diminution de la capacité de clairance d’Aβ. L’objectif #2 nécessitera la mise en place de co-cultures neurones-glie pour évaluer l’impact d’APOE et son polymorphisme sur l’amyloïdogenèse en mesurant notamment les niveaux de production des peptides Aβ, ainsi que des analyses en imagerie pour étudier l’impact sur le réseau endosome-lysosome neuronal. Dans un troisième objectif, nous utiliserons des approches de surexpression et perte de fonction ciblant des protéase actives dans la protéolyse d’APOE et/ou ses récepteurs afin d’évaluer l’impact fonctionnel. Des approches pharmacologiques seront également envisagées.

Résultats attendus

Nous attendons démontrer que l’APOE4 altère : i) les mécanismes neuroinflammatoires supportés par les cellules gliales ; ii) les processus cellulaires neuronaux et gliaux assurant un équilibre production/dégradation d’Aβ. Nous anticipons que la modulation d’APOE peut contrôler ces processus pathogéniques.

Profil du candidat demandé

Expérience souhaitée en culture cellulaire (iPS) et différenciation cellulaire, ainsi qu’une maitrise de méthodes de biochimie (ex. Western Blot, ELISA). Une expérience en édition du génome et/ou imagerie et/ou pharmacologie serait un atout.

Team Publications