Abstract
Porcine fat deposition is an important economic trait of pig breeds, and understanding the gene regulatory network in adipocytes is essential for modern pig breeding. In a previous study, we demonstrated that miR-29a negatively regulates the differentiation of porcine adipocytes. In this study, we investigated the roles of miR-29b/c in porcine adipocytes and the underlying mechanisms. Using EdU staining and the CCK-8 assay, we observed that transfection with the miR-29b/c agomir promoted the proliferation of porcine intramuscular (IM) and subcutaneous (SC) adipocytes by altering the expression of cell-cycle-related genes. According to the results of oil red O staining and western blot analysis, transfection with the miR-29b/c agomir suppressed the differentiation of porcine SC and IM adipocytes via the AKT/PKA/MAPK signalling pathway. Furthermore, we proved that miR-29b/c regulates porcine adipocytes by directly targeting the 3'-untranslated region (3'UTR) of CTRP6 using a dual-luciferase reporter assay. Finally, co-transfection with miR-29b/c and CTRP6 partially restored the changes of phenotype and gene expression induced by miR-29b/c overexpression in 3T3-L1 adipocytes. Taken together, our data demonstrate that both miR-29b and miR-29 c negatively regulate porcine adipogenesis by targeting CTRP6, which furthers our understanding of the gene network that regulates fat deposition in pigs.