PGC-1α in the myofibers regulates the balance between myogenic and adipogenic progenitors affecting muscle regeneration

Skeletal muscle repair is accomplished by satellite cells (MuSCs) in cooperation with interstitial stromal cells (ISCs), but the relationship between the function of these cells and the metabolic state of myofibers remains unclear. This study reports an altered proportion of MuSCs and ISCs (including adipogenesis-regulatory cells; Aregs) induced by the transgenic overexpression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha) in the myofibers (MCK-PGC-1 alpha mice). Although PGC-1 alpha-driven increase of MuSCs does not accelerate muscle regeneration, myogenic progenitors isolated from MCK-PGC-1 alpha mice and transplanted into intact and regenerating muscles are more prone to fuse with recipient myofibers than those derived from wild-type donors. Moreover, both young and aged MCK-PGC-1 alpha animals exhibit reduced perilipin-positive areas when challenged with an adipogenic stimulus, demonstrating low propensity to accumulate adipocytes within the muscle. Overall, these results unveil that increased PGC-1 alpha expression in the myofibers favors pro-myogenic and anti-adipogenic cell populations in the skeletal muscle.