Extracellular Vesicle-Mediated miR-155 from Visceral Adipocytes Induces Skeletal Muscle Dysplasia in Obesity.

Obesity poses a serious threat to human health, with induced skeletal muscle dysfunction significantly increasing the risk of metabolic syndrome. In obesity, it is known that visceral adipose tissue (VAT) mediates the dysregulation of the adipose-muscle axis through exosome-delivered miRNAs, but the associated regulatory mechanisms remain incompletely elucidated. This study established an AAV-mediated miR-155 obese mouse model and a co-culture system (HFD VAD-evs/RAW264.7 cells/C2C12 cells) to demonstrate that high-fat diet-induced VA-derived extracellular vesicles (HFD VAD-evs) preferentially accumulate in skeletal muscle and induce developmental impairment. HFD VAD-evs disrupt skeletal muscle homeostasis through dual mechanisms: the direct suppression of myoblast development via exosomal miR-155 cargo and the indirect inhibition of myogenesis through macrophage-mediated inflammatory responses in skeletal muscle. Notably, miR-155 inhibition in HFD VAD-evs reversed obesity-associated myogenic deficits. These findings provide novel mechanistic insights into obesity-induced skeletal muscle dysregulation and facilitate potential therapeutic strategies targeting exosomal miRNA signaling.