miR-320 regulates myogenesis by targeting growth factor receptor-bound protein-2 and ameliorates myotubes atrophy

Loss of muscle mass can lead to diseases such as sarcopenia, diabetes, and obesity, which can worsen the quality of life and increase the incidence of disease. Therefore, understanding the mechanism underlying skeletal muscle differentiation is vital to prevent muscle diseases. We previously found that microRNA-320 (miR-320) is highly expressed in the lean muscle-type pigs, but its regulatory role in myogenesis remains unclear. The bioinformatics prediction indicated that miR-320 could bind to the 3 'untranslated region of growth factor receptor-bound protein-2 (Grb2). We hypothesized that miR-320 targets Grb2 to regulate myoblasts differentiation. To verify this, we transfected miR-320 mimic and inhibitor into C2C12 myoblasts to assess the role of miR-320 during myoblasts differentiation. We used real-time qPCR, luciferase reporter assays, and western blotting to confirm that miR-320 directly targets Grb2 to promote myoblasts differentiation. Moreover, by using a dexamethasone-induced atrophic model of myotubes, we discovered that miR-320 promotes the repair of damaged myotubes. Our findings expand understanding of miRNAs and genes related to regulating skeletal muscle differentiation, and provide insight into underlying therapeutic strategies for muscle diseases.