MicroRNA‑23a‑5p mediates the proliferation and differentiation of C2C12 myoblasts.

Skeletal myogenesis is a highly ordered and complex biological process that is mediated by numerous regulatory factors. In previous studies, it has been demonstrated that microRNAs (miRs) and long non‑coding RNAs (lncRNAs) serve key roles in skeletal myogenesis. The present study showed that the expression levels of miR‑23a‑5p showed a dynamic change from decrease to increase during C2C12 myoblast proliferation and differentiation. Functional analysis using 5‑ethynyl‑2'‑deoxyuridine proliferation and Cell Counting Kit‑8 detection assays indicated that overexpression of miR‑23a‑5p significantly promoted C2C12 myoblast proliferation compared with the negative control. In addition, in C2C12 myoblasts transfected with miR‑23a‑5p mimics, increased expression levels of regulators associated with cell proliferation (Cyclin E, CCND1 and Cyclin B) were observed compared with the negative control. By contrast, overexpression of miR‑23a‑5p decreased the expression levels of specific‑myogenesis factors (MyoD, MyoG and Myf5) and decreased C2C12 myoblast differentiation. Luciferase activity assays indicated that miR‑23a‑5p suppressed the luciferase activity of lncDum. Further analysis demonstrated that miR‑23a‑5p not only showed an opposite expression level pattern compared with lncDum, which was first increased and then decreased, but also had an opposite effect on the proliferation and differentiation of C2C12 myoblasts compared with lncDum which inhibited cell proliferation and promoted cell differentiation. Taken together, these results indicated that miR‑23a‑5p may mediate the proliferation and differentiation of C2C12 myoblasts, which may be involved in lncDum regulation.