MicroRNA-351-5p mediates skeletal myogenesis by directly targeting lactamase-β and is regulated by lnc-mg

Abstract

Skeletal muscle is an important and complex organ with a variety of functions in humans and animals. Skeletal myogenesis is a multistep and complex process, and increasing evidence suggests thatmicroRNAs (miRNAs) and longnoncodingRNAs(lncRNAs)play critical roles in skeletal myogenesis. In this study the expression of miR-351- 5p is dynamically regulated during skeletal myogenesis in vitro and in vivo. Cell-counting kit-8, qRT-PCR, and EdU immunofluorescence analysis showed that miR-351-5p overexpression promoted the proliferation and inhibited the differentiation of C2C12 myoblast, whereas inhibition of miR-351-5p had the opposite effect. In addition, miR-351-5p mediated the regulation ofmuscle fiber type transition in vivo. In vitro, loss ofmiR-351-5p in muscle tissues promoted muscle hypertrophy and increased slow-twitch fibers in the gastrocnemiusmuscles of mice. Luciferase reporter assay and functional analyses demonstrated that lactamase b (LACTB) is a direct target of miR-351-5p involved in the regulation of skeletal myogenesis. Expression levels of amyogenesis-associated lncRNA (lnc-mg) correlated negatively with miR-351-5p andpositivelywithLACTBduringC2C12 myoblast proliferation anddifferentiation. Further analyses showed that lnc-mg acted as a molecular sponge for miR-351-5p, demonstrating its involvement in the negative regulation of LACTB by miR-351-5p during skeletal myogenesis. These findings indicate that miRNA-351-5p functions in skeletal myogenesis by targeting LACTB and is regulated by lnc-mg, supporting the role of the competing endogenous RNAnetwork in skeletal myogenesis.