Stem Cell Aging and Rejuvenation in the Skeletal Muscle System

Aging is an unavoidable process associated with a progressive decline of muscle mass, strength, and regenerative ability. Satellite cells are a muscle stem cell (MuSC) population that plays a key role in mammalian muscle regeneration, by awakening from quiescence and then migrating to sites of damage, expanding in number to generate progenitor cells, and then either differentiating to rebuild the muscle tissue or self-renewing to repopulate the stem cell pool. Emerging evidence suggests that the aging process impairs the activation potential and the regenerative capacity of MuSCs. This review explores some of the recent discoveries of how mis-regulation of intrinsic and extrinsic mechanisms drive the decline of MuSC function in aging muscles, and we discuss new strategies to rejuvenate aged MuSC function for regenerative medicine. Understanding these processes will speed up the development of novel therapeutics for counteracting muscle loss and improve muscle healing in the elderly.