bta-miR-378 promote the differentiation of bovine skeletal muscle-derived satellite cells.

The mechanism by which bta-miR-378 regulates bovine skeletal muscle-derived satellite cell (bMDSC) myogenesis remains unknown. In this study, stem-loop RT-PCR was used to assess bta-miR-378 expression during the proliferation and differentiation of bMDSCs. The results showed that bta-miR-378 expression did not obviously change during bMDSC proliferation but increased significantly when bMDSCs began to differentiate. Then, a bta-miR-378 mimic (bta-miR-378-M) and bta-miR-378 inhibitor (bta-miR-378-I) were transfected into bMDSCs to explore the effect of bta-miR-378 on bMDSC differentiation. Cell differentiation was detected using myosin heavy chain 3 immunofluorescence, myotube formation, and desmin and myogenin western blotting analyses. As expected, bta-miR-378-M enhanced bMDSC differentiation, whereas bta-miR-378-I had the opposite effect. Moreover, luciferase reporter and western blotting assays showed that bta-miR-378 directly targeted the 3'-untranslated regions of DNA polymerase alpha subunit B (POLA2) to regulate its protein expression. In summary, these data indicate that bta-miR-378 targets POLA2 to promote the differentiation of bMDSCs, which provides further insight into the biological functions of bta-miR-378 in bovines.