Ssc-miR-130b Enhances Cell Proliferation and Represses Adipogenesis of Primary Cultured Intramuscular Preadipocytes in Pigs

In the efforts towards germplasm innovation of livestock and poultry, strategies to improve meat quality have faced some increasingly challenging and dynamic concerns. Intramuscular fat (IMF) content and backfat thickness are two important traits contributing to meat quality. MicroRNAs (miRNAs)-a class of endogenous noncoding RNAs maintaining cell homeostasis by inhibiting target gene expression-have been proven as critical regulators of body fat deposition, thus affecting farm animal production. Our previous in vitro and in vivo models of pigs have clarified that miR-130b overexpression can obviously suppress adipogenesis of subcutaneous preadipocytes and lower backfat thickness. However, the way miR-130b regulates proliferation and adipogenesis of primary cultured porcine intramuscular preadipocytes (PIMPA) and the underlying mechanism are still unknown. PIMPA derived from longissimus dorsi muscle were employed to examine the role of miR-130b in proliferation and adipogenesis and to further elucidate its underlying mechanism. Lipid deposition in cytoplasm was evaluated by TG quantification and ORO-staining, and EDU-staining was employed to measure cell proliferation. Adipogenic and proliferation-related gene expression were conducted by qPCR and Western blot. MiR-130b overexpression markedly stimulated proliferation of PIMPA by increasing cell cycle-related gene expression. Furthermore, overexpression of miR-130b significantly inhibited adipogenic differentiation of PIMPA, mainly by inhibiting expression of adipogenic differentiation marker genes PPAR-γ and SREBP1. In addition, we proved that miR-130b significantly inhibited expression of PPAR-γ downstream target genes and ultimately repressed adipogenesis. Ssc-miR-130b accelerated proliferation but inhibited adipogenic differentiation of PIMPA, contributing to an enhanced knowledge of the function of ssc-miR-130b in lipid deposition, and providing potential implications for enhancing pork quality.