Ning Ding

Background: Intramuscular fat (IMF) content is an important factor in porcine meat quality. Previously, we showed that miR-34a was less abundant in liver tissue from pigs with higher backfat thickness, compared to pigs with lower backfat thickness. The purpose of this present study was to explore the role of miR-34a in adipogenesis.Result: Bioinformatics analysis identified Acyl-CoA synthetase long chain family member 4 (ACSL4) as a putative target of miR-34a. Using a luciferase reporter assay, we verified that miR-34a binds theACSL4mRNA at the 3’UTR. To examine the role of the miR-34a-ACSL4interaction in IMF deposition in the pig, mRNA and protein expression of theACSL4gene was measured in primary intramuscular preadipocytes transfected with miR-34a mimic and inhibitor. Our results showed thatACSL4is expressed throughout the entire differentiation process in pig preadipocytes, similar to the lipogenesis-associated genesPPARγandaP2.Transfection with miR-34a mimic reduced lipid droplet formation during adipogenesis, while miR-34a inhibitor increased lipid droplet accumulation. Transfection with miR-34a mimic also reduced the mRNA and protein expression ofACSL4and lipogenesis genes, includingPPARγ, aP2,andSREBP-1C, but increased the expression of steatolysis genes such asATGLandSirt1. In contrast, the miR-34a inhibitor had the opposite effect on gene expression. Further, knockdown ofACSL4decreased lipid droplet accumulation.Conclusions: Our results support the hypothesis that miR-34a regulates intramuscular fat deposition in porcine adipocytes by targetingACSL4.