miR-205-5p negatively regulates hepatic acetyl-CoA carboxylase β mRNA in lipid metabolism of Oreochromis niloticus

MicroRNAs (miRNAs) are non-coding RNAs that function as post-transcriptional gene regulators and that play vital roles controlling lipid metabolism. miR-205 is an important miRNA related to adipogenesis and lipid metabolism. However, little is known about the potential role of miR-205-5p in genetically improved farmed tilapia (GIFT, Oreochromis niloticus). In this study, we used miRanda software to search for potential miR-205-5p target genes and found a lipid-metabolism-related gene called acetyl-CoA carboxylase beta (ACAC beta). Quantitative real-time polymerase chain reaction data indicated that there may be a negative regulation relationship between miR 205-5p and ACAC beta gene expression under HFD rearing. Using luciferase reporter assays, we verified the binding site of miR-205-5p in the 3'-untranslated region of the ACAC beta mRNA. Furthermore, an in vivo functional analysis of miR 205 5p was performed by injecting GIFT juveniles with a miR-205-5p antagomir. Reduced levels of miR-205-5p in GIFT liver increased ACAC beta mRNA expression 12 h post-injection. miR-205-5p suppression also increased fatty acid synthase and peroxisome proliferator-activated receptor-alpha mRNA levels 48 h and 120 h post-injection, respectively. Taken together, our results indicate that miR-205-5p negative regulates hepatic ACAC beta mRNA expression, and may serve as an important regulator in controlling hepatic lipid metabolism in GIFT.