miR-27a is an important adipogenesis regulator associated with differential lipid accumulation between intramuscular and subcutaneous adipose tissues of sheep

Micro ribonucleic acids (miRNAs) are crucial regulators for various biological processes. Despite important function in the proliferation and differentiation of preadipocytes, miRNA studies are limited in regional differences in adipogenesis. Here, we show that miR-27a plays an important role in regulating differential lipid accumulation between intramuscular (IM) and subcutaneous (SC) adipose tissues in sheep. In vivo, we observed that miR-27a expression in IM adipose tissue is more abundant than in SC adipose tissue. However, the expression of Peroxisome Proliferator-Activated Receptor Gamma (PPARG) and retinoid X receptor alpha (RXR alpha) in IM adipose tissue was significantly lower than that in SC adipose tissue. In the ovine preadipocyte differentiation model, we found that the expression of miR-27a was significantly decreased in differentiated ovine adipocytes. Overexpression of miR-27a significantly downregulated the expression of PPARG and RXR alpha and suppressed the accumulation of triglyceride but promoted the proliferation of ovine preadipocytes. Whereas, inhibition of miR-27a suppressed preadipocyte proliferation but enhanced PPARG and RXR alpha expression and lipid droplet formation. In addition, dual-luciferase activity assays showed that RXR alpha was a direct target of miR-27a. Thus, miR-27a enhances ovine preadipocytes proliferation and inhibits ovine preadipocytes differentiation through regulating the expression of target RXR alpha. Collectively, our study demonstrates the functional importance of miR-27a in ovine adipogenesis and provides novel insights into exploring regional differences in adipogenesis. (C) 2019 Elsevier Inc. All rights reserved.