miR-128-3p regulates 3T3-L1 adipogenesis and lipolysis by targeting <Emphasis Type="Italic">Pparg</Emphasis> and <Emphasis Type="Italic">Sertad2</Emphasis>

Differentiation of adipocytes and their aggregation to adipose tissue are critical for mammalian growth and development. MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs that play important roles in adipogenesis and lipid metabolism. miR-128-3p may contribute to adipose tissue development according to the previous studies. However, the role of miR-128-3p in the process of preadipocyte differentiation and lipid metabolism is not yet understood. The purpose of this research was to investigate the biological function and molecular mechanism of miR-128-3p in 3T3-L1 cells. In the present study, we found that miR-128-3p was downregulated during the process of 3T3-L1 preadipocyte differentiation. Overexpression of miR-128-3p obstructed the expressions of adipogenic marker genes as well as the lipid droplets accumulation and triglyceride content, suggesting the importance of miR-128-3p for adipogenesis. Moreover, miR-128-3p could lead to the retardation of cell proliferation in 3T3-L1 preadipocytes. Further evidences showed that, as a negative regulator of adipogenesis, miR-128-3p could directly target peroxisome proliferator-activated receptor γ (Pparg) which resulted in the suppression of 3T3-L1 preadipocyte differentiation, and miR-128-3p could also bind with SERTA domain containing 2 (Sertad2) which drove triglyceride hydrolysis and lipolysis. In addition, inhibition of Sertad2 with siRNA displayed the same effects as overexpression of miR-128-3p. Our research demonstrated that miR-128-3p impeded 3T3-L1 adipogenesis by targeting Pparg and Sertad2, resulting in the obstruction of preadipocyte differentiation and promotion of lipolysis. Taken together, this study offers profound insight into the mechanism of miRNA-mediated adipogenesis and lipid metabolism.