Development and regulation of the stem cell niche

Speaker: Shahragim Tajbakhsh, Stem Cells & Development Unit, Institut Pasteur, Paris 

This is a joint seminar hosted by the Centre for Stem Cells & Regenerative Medicine and the Randall Centre for Cell & Molecular Biophysics

Regulation of skeletal muscle stem cells during homeostasis and regeneration involves the interplay of extrinsic and intrinsic cues. The mechanisms by which niche molecules and intrinsic factors regulate muscle stem cell quiescence and properties remain largely unknown. In a series of studies, we investigated Notch as a key mediator of muscle stem cell stability and fate. Notably, we found that Notch/RBPJ-bound regulatory elements are located adjacent to specific collagen genes in adult muscle stem cells, and investigated how extrinsic cues assure stem cell quiescence. In addition, we identified a microRNA pathway that is modulated by Notch, and that is required for stabilizing muscle stem cells in their niche by regulating the migration capacity of the muscle stem cell. These observations lead us to propose a two-step mechanism for niche occupancy by muscle stem cells.