Résumé :
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Environment of stem cells plays a crucial role in controlling their fate: quiescence, proliferation, differentiation, self-renewal. Environment of satellite cells comprise endothelial cells, periendothelial cells, immune cells and fibroblastic cells. We explore the role of the satellite cell neighbours in the context of normal steady-state and regenerating muscle.Satellite cells interact with endothelial cells to promote both myogenesis and angiogenesis while they interact with periendothelial cells to trigger their self-renewal and maintain their quiescence. At time of regeneration, myogenic cells interact with macrophages that sequentially promote their proliferation and their differentiation to form new large myofibres. Experiments show that polarized macrophages finely regulate the sequential steps of myogenesis through the action of various effectors, including cytokines and growth factors. Altogether, our results show that satellite cells develop specific interactions with their neighbouring cells and that these interactions regulate their behaviour.
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