Epigenetic control of muscle stem cells: time for a new dimension

Muscle stem cells (MuSCs) are responsible for skeletal muscle homeostasis and repair. In response to extracellular cues, MuSCs activate from quiescence, expand, differentiate into mature myofibers, and self-renew within their regenerative niche. These steps are accomplished by the dynamic action of different chromatin-modifying enzymes that, cooperating with myogenic transcription factors, coordinately regulate defined transcriptional programs. Here, we review the current knowledge on the epigenetic dynamics that allow MuSCs’ fate decisions. We describe the emerging mechanisms showing how chromatin topology impacts the 3D genome architecture of MuSCs during myogenesis. Because these processes contribute to shape and maintain cell identity, we highlight how defects in proper epigenetic control of MuSCs’ fate decisions underlie the pathogenesis of muscle diseases, causing the acquisition of derailed cell fates and the incapacity to properly self-renew.