Myogenic differentiation-derived small extracellular vesicles as a therapeutic strategy for miR-193b-3p-mediated...

The regeneration of skeletal muscle involves precisely regulated intercellular communication, including extracellular vesicle (EV)-mediated processes. In this study, we show that during in vitro myogenic differentiation of human skeletal muscle progenitor cells (myoblasts), miR-193b-3p accumulates within small EVs (sEVs) in a temporally regulated manner. Both sEV-mediated and synthetic delivery of miR-193b-3p enhanced myogenic differentiation in vitro and promoted histological recovery in a murine volumetric muscle loss model. Mechanistically, we demonstrate that miR-193b-3p directly suppresses adapter-related protein complex 2 subunit mu 1 (AP2M1), a clathrin-associated adapter protein that has not been well characterized in muscle biology, and identify it as a negative regulator of myogenic progression. AP2M1 knockdown phenocopied the effects of miR-193b-3p, suggesting that this regulatory axis may contribute to muscle regeneration. In addition, transcriptomic analyses of aged rodent and sarcopenic human datasets revealed conserved upregulation of AP2M1 in degenerative muscle states, supporting its potential clinical relevance. Collectively, these findings reveal a myogenic differentiation-dependent, sEV-mediated miRNA regulatory mechanism that contributes to muscle regeneration. Based on these results, we propose the miR-193b-3p-AP2M1 axis as a potential therapeutic target for muscle-wasting disorders.