MicroRNA-130b and microRNA-374b mediate the effect of maternal dietary protein on offspring lipid metabolism in Meishan pigs

To investigate whether the effect of maternal dietary protein on offspring lipid metabolism is mediated by microRNA (miRNA), fourteen Meishan sows were fed either low-protein (LP, half of standard protein (SP) level, n 7) or SP (n 7) diets throughout gestation and lactation periods. PPAR-gamma and CCAAT/enhancer-binding protein-beta (C/EBP-beta) protein expression was evaluated. The expression of miRNA predicted to directly target PPAR-gamma and C/EBP-beta in the subcutaneous fat of offspring at weaning age was determined, and the functions of these potential miRNA were verified. The results showed that piglet body weight and back fat thickness were significantly decreased in the LP group compared with the SP group (P<0.05). The protein level of PPAR-gamma was significantly decreased and C/EBP-beta protein expression was also decreased, though not significantly (P=0.056), in the subcutaneous fat of the LP group. Furthermore, miRNA expression analysis showed that miR-130b, targeting the PPAR-gamma 3'-untranslated region (UTR), and miR-374b, targeting the C/EBP-beta 3'-UTR, were significantly increased in the LP group compared with the SP group; other candidate regulatory miRNA were expressed similarly in both groups. Dual luciferase activity assay results indicated that miR-130b directly recognised and bound to the 3'-UTR of PPAR-gamma and thereby suppressed PPAR-gamma gene expression. Similar results were found for miR-374b and the 3'-UTR of C/EBP-beta. The present study showed that miR-130b and miR-374b are involved in the effect of maternal dietary protein on offspring lipid metabolism in pigs. These results shed new light on our understanding of the maternal effect on offspring lipid deposition.