MicroRNA Hsa-miR-138 Inhibits Adipogenic Differentiation of Human Adipose Tissue-derived Mesenchymal Stem Cells Through Adenovirus EID-1

A better understanding of the molecular mechanisms underlying the differentiation of human adipose tissue-derived mesenchymal stem cells (hAD-MSCs) could provide new insights into the pathogenesis of a number of diseases, such as obesity and diabetes, and broaden the spectrum of potential hAD-MSCs-based cell therapy. In this study, we reported that a human microRNA, hsa-miR-138, could inhibit the adipogenic differentiation of hAD-MSCs. Our results showed that miR-138 was significantly down-regulated during adipogenic differentiation. Overexpression of miR-138 in hAD-MSCs could effectively reduce lipid droplets accumulation, inhibit expression of key adipogenic transcription factors cytidine-cytidine-adenosine-adenosine-thymidine (CCAAT) enhancer binding protein alpha and peroxisome proliferator-activated receptor gamma 2 as well as several other adipogenic marker genes, such as fatty acid binding protein 4 and lipoprotein lipase. Further studies showed that the expression of adenovirus early region 1-A-like inhibitor of differentiation 1 (EID-1), a nuclear receptor coregulator, was inversely correlated with that of miR-138 when hAD-MSCs were differentiated into adipocytes. Knockdown of EID-1 by RNA interference inhibited adipocyte differentiation of hAD-MSCs. In addition, luciferase reporter assays demonstrated that miR-138 directly targeted the 3' untranslated region of EID-1, implying that the negative role of miR-138 in the adipocyte differentiation of hAD-MSCs is at least partially mediated via repressing EID-1. Taken together, this study shows that miR-138 plays a negative role in adipogenic differentiation and sheds light on the role of miRNAs during differentiation of hAD-MSCs toward adipocytes.