miR-493-3p promotes porcine muscle satellite cells differentiation and the formation of slow muscle fibers through MKK7/JNK axis

MicroRNAs (miRNAs) are key regulators of porcine myogenesis. In this study, we elucidated the regulatory role of miR-493-3p in skeletal muscle development. miR-493-3p showed a preferential expression pattern in skeletal muscle, with significantly higher expression in slow-twitch muscle than in fast-twitch muscle. Functional analyses revealed that overexpression of miR-493-3p inhibited the proliferation of porcine primary muscle satellite cells (MSCs) while promoting their differentiation and slow-twitch myofiber formation. In mouse, adeno-associated virus (AAV)-mediated overexpression of miR-493-3p significantly increased the cross-sectional area (CSA) of tibialis anterior muscle and promoted the proportion of slow-twitch myofibers. Furthermore, bioinformatic analysis and Dual-Luciferase Reporter Assay identified MAP kinase kinase 7 ( MKK7 ) as a direct target of miR-493-3p. The miR-493-3p inhibited MKK7 expression, consequently reducing phosphorylated c-Jun N-terminal kinase (p-JNK) levels. Overall, our data demonstrate that miR-493-3p promotes porcine MSC differentiation and slow-twitch myofiber formation via inhibiting the MKK7/JNK axis. This finding enhances our understanding of miRNA-regulated skeletal muscle developmental networks and provides a potential strategy for improving pork production and meat quality. • miR-493-3p is a skeletal muscle-enriched miRNA with preferential expression in slow-twitch myofibers. • miR-493-3p suppresses proliferation but promotes differentiation and slow-twitch myofiber formation in porcine MSCs. • AAV-miR-493-3p overexpression increases muscle size and slow-twitch myofiber ratio in mouse tibialis anterior muscle. • MKK7/JNK axis is a mechanistic target of miR-493-3p. • A molecular framework for improving meat quality and livestock production via miRNA-driven muscle development is proposed.