CircINSR regulates fetal bovine muscle and fat development

Abstract

Background: The level of muscle development directly affects the production efficiency of livestock, and the content of intramuscular fat (IMF) is an important factor affecting meat quality. Nevertheless, the molecular mechanism of embryonic circular RNA in muscle and IMF development remains largely unknown. Methods: In this study, we isolated myoblasts and intramuscular preadipocytes from fetal bovine skeletal muscle. Oil Red O and BODIPY staining were used to identify lipid droplets of preadipocytes, and anti-MyHC immunofluorescence was used to identify myotubes differentiated from myoblasts. Bioinformatics, dual fluorescence reporter system, and RNA immunoprecipitation were used to determine the interactions between circINSR and miR-15/16 family. Molecular and biochemical assays were used to confirm the role of circINSR in myoblasts and intramuscular preadipocytes. Results: We found that the isolated myoblasts and preadipocytes can differentiate normally. Besides, circINSR severed as a sponge of miR-15/16 family, which targeting CyclinD1 and Bcl-2. CircINSR overexpression significantly promoted myoblasts and preadipocytes proliferation, and inhibited cell apoptosis. In addition, circINSR inhibited preadipocytes adipogenesis by alleviating the inhibition of miR-15/16 on target genes FOXO1 and EPT1. Conclusions: Taken together, our study demonstrated circINSR as a regulator of embryonic muscle and IMF development.