Alexandra Benchoua : Group leader, (CECS)
Laure Chatrousse: PhD, Research associate (CECS, Genetic forms of autism)
Claire Boissart : Engineer (CECS, Lesch-Nyhan Disease)
Valentin Ruillier: PharmD, PhD student (Lesch-Nyhan Disease)
Aims and background:
The term “Neuroplasticity” refers to the ability of the human brain to change as a result of one’s experience. This capacity of adaptation results from the production of new neurons, the addition or removing of connections between neurons or of changes in the strength of these connections. Neuroplasticity is a key feature of the normal brain development and the basis of learning and memory. Its impairment during pregnancy or early childhood, as a result of exposition to pathogens, toxic agents or as a consequence of genetic mutations, leads to severe neurological deficits including mental retardation, autistic syndromes and some psychiatric disorders. In contrast, re-introduction of neurogenesis or stimulation of neuroplasticity in the adult brain both represent promising therapeutic avenues to improve psychiatric and neurodegenerative conditions.
In this context, human Puripotent Stem Cells (hPSC) cells represent a unique tool to model the key steps governing human brain plasticity in vitro. Our team study how neural precursors are produced from pluripotent embryonic stem cells, how these Neural Stem Cells (NSC) self-renew to maintain the pool of precursors and, finally, how post-mitotic mature neurons form and connect to each others. Our goal is to identify signaling pathways which control or coordinate these different phenotypic transitions and to evaluate how these pathways can be influenced by the cellular environment, altered in pathological contexts or serve as therapeutic targets.
Strategy, means and methods:
We use hPSC as a source of starting cells to recapitulate key step of neurogenesis/neuroplasticity respecting as much as possible important developmental milestones. More particularly, we have developped a protocol to induce efficicent and synchronized differentiation of PSC into the neural lineage in order to capture stable populations of self-renewing neural stem cells (NSC). These cells provide the starting material to produce human neurons and follow in real-time their maturation and connections into complex networks. The adaptation of these culture systems to miniaturized formats suitable for High Throughput Screening combined to the development of image-based automated phenotypical analysis help revealing any alteration induced by a genetic mutation responsible for a neurodevelopmental disorder. It also raises the possibility to interfere with these systems by any means (small molecules, FDA approved marketed drugs) and evaluate the consequences on both neurogenesis and neuroplasticity.
Results and future prospects:
One main achievement of our team was the development of a genuine protocol which allows the formation of neural tube-like structures in vitro in a synchronized and homogeneous manner. This system was used to identify micro-RNAs involved in the process of neural commitment (see Boissart et al., 2012). More technically, the very high efficiency of this system allowed the isolation and expansion of NSC in a standardized manner and qualified NSC for industrial purposes. We have defined the culture conditions necessary to maintain these cells as an adherent homogeneous self-renewing population and characterized their potential to produce functional embryonic neurons. The neuronal differentiation protocol was miniaturized in a 384 well plate screening format and several tests were developed to analyze in an automated manner different aspects of neurogenesis and neuroplasticity using High Content Analyses systems (see Boissart et al., 2013).This screening model was validated during our collaboration with the pharmaceutical group Roche and had revealed key signalling pathways involved in the control of NSC self-renewal (see Georges et al., 2015).
We are now using these technics starting from patient-derived PSC to increase our understanding and try to find new therapeutic approaches for devastating neurodevelopmental disorders. We mainly focus on:
- Lesch-Nyhan Disease (HPRT mutation), a metabolic disorder affecting the development of dopaminergic neurons,
- Genetic forms of Autism induced by mutation in genes affecting the connectivity of cortical neurons (SHANK-3, MEF2C…).
- Interactions between FDA approved drugs and neurodevelopmental disorder-associated gene expression
BENCHOUA, Alexandra; (FR). PERRIER, Anselme; (FR). AUBRY, Laetitia; (FR).
Method and medium for neural differentiation of pluripotent cells.
- Pr. Thomas Bourgeron, Institut Pasteur, Human Genetics and cognitive function, CNRS URA 2182, Institut Pasteur, Paris
- Pr Richard Delorme, Robert Debré Pediatric Hospital, Paris, France
- Pr J.L Mandel et Dr Amélie Piton, IGBMC, Strasbourg, France
- Drs. Fatiha Fjeldskaar, Christoph Patsch and Martin Graf, F.Hoffmann-Laroche Ltd, Basel, Switzerland
- Dr Katie Binley, Oxford Biomedica, Oxford, UK
- Pr Stéphane Palfi, Henri Mondor Hospital, Créteil, France
- Drs Mylène Hubert-Martrou and Pr Jack-Yves Deschamps, Boisbonne Center, Nantes, France
- Pr Marie Anne Colle, Animal Physiopathology and Biotherapy of the CNS, Nantes, France
- Dr Muriel Coulpier, ENVA, Maison-Alfort, France
- Dr Mathieu Gabut, Cancer Research Center, Lyon, France