Effect of miR-149-5p on intramuscular fat deposition in pigs based on metabolomics and transcriptomics

As one of the important traits in pig production, meat quality has important research significance and value. Intramuscular fat (IMF) content is one of the most important factors affecting pork quality. Many experimental studies have shown that IMF content is closely related to the flavor, tenderness, juiciness, water-holding capacity, and marble of pork. Therefore, it is of great significance to study the mechanism of porcine IMF deposition. Previous research indicated that miR-149-5p promoted the proliferation of porcine intramuscular (IM) preadipocytes and decreased their ability to differentiate, albeit the exact mechanism of action is unknown. In vitro experiments, miR-149-5p had the opposite trend of fat deposition in Queshan Black and foreign pigs. The present study conducted transcriptomics and metabolomics analyses of porcine IM preadipocytes overexpressing miR-149-5p to verify their effects on lipid formation. According to metabolomics analysis, the overexpression of miR-149-5p significantly changed the lipid, organic acid, and organic oxygen metabolites of porcine IM preadipocytes. The overexpression of miR-149-5p significantly changed 115 metabolites, including 105 up-regulated and 10 down-regulated ones, and significantly changed the composition of lipid, organic acid, and organic oxygen metabolism-related metabolites. RNA-seq analysis showed that overexpression of miR-149-5p significantly altered 857 genes, of which 442 were up-regulated, and 415 were down-regulated, with enrichment to MAPK, IL-17, PI3K-Akt, and ErbB signaling pathways. In addition, the overexpression of miR-149-5p may affect the transport of Cu 2+ by targeting ATP7A and inhibiting fat differentiation. These findings elucidate the regulatory function of miR-149-5p in porcine IM preadipocytes, which may be a key target for controlling pork quality.