miR-21-3p Targets <i>Elovl5</i> and Regulates Triglyceride Production in Mammary Epithelial Cells of Cow

Abstract

MicroRNAs (miRNAs) can regulate a variety of biological functions such as fat and cholesterol synthesis, translocation, and utilization by regulating degradation or by inhibiting target mRNA translation. In this study, the target gene of miR-21-3p was analyzed through bioinformatics, which predicted Elovl5. Furthermore, miR-21-3p was verified for regulation of triglyceride expression. The results showed that luciferase activity was significantly lower in cells cotransfected with miR-21-3p and Elovl5 reporter vector, pmiR-RB-REPORT-Elovl5-WT, than in cells with miR-21-3p and reporter control vectors, pmiR-RB-REPORT-Elovl5-mut and pmiR-RB-REPORT-Elovl5-si, indicating that target sites exist in the 3'UTR of Elovl5. Further analysis using qPCR and Western blotting showed that the expression of miR-21-3p negatively correlated with the levels of Elovl5 mRNA and protein, suggesting that miR-21-3p might play an important role in regulating Elovl5 gene expression. Finally, transfection with bta-miR-21-3p mimics, bta-miR-21-3p inhibitor, or miRNA-ShNC in mammary epithelial cells suggested that bta-miR-21-3p promotes triglyceride production, which might be attributed to the expression of the target gene Elovl5.