Ubiquitin-specific peptidase 8 regulates proliferation and early differentiation of sheep skeletal muscle satellite cells

Ubiquitin-specific protease 8 (USP8), a member of the ubiquitin-specific protease (USP) family, was originally identified as playing a role in the regulation of growth and cell cycle. However, its functional role in myogenesis is unknown. In this study, we investigated the role of USP8 in proliferation and differentiation of sheep skeletal muscle satellite cells. The results showed that the expression level of USP8 was significantly increased on days 2 and 3 following the induction of the differentiation process. Furthermore, knocking down USP8 resulted in a significant increase in myogenin-positive cells, and promoted early differentiation of satellite cells by regulating the expression level of paired box 7 (PAX7). Additionally, knocking down USP8 suppressed muscle satellite cell proliferation, possibly explaining that the relative mRNA level of USP8 was linearly related to muscle fibre density of Hu sheep. Overall, our research demonstrates that USP8 plays a role in proliferation and early differentiation of skeletal muscle satellite cells.