MicroRNA-668 alleviates renal fibrosis through PPARα/PGC-1α pathway

Abstract

BACKGROUND: The involvement of microRNA-668 (miR-668) in the onset and progression of renal fibrosis remains unclear. To this end, we aimed to explore the relevant mechanism of miR-668 in renal fibrosis. METHODS: C57BL/6 J male mice were randomly divided into sham-operated, unilateral ureteral obstruction (UUO), and UUO-fenofibrate groups. Based on transfection and drug intervention, HK-2 cells were divided into blank control, TGF-β1, TGF-β1 + fenofibrate (PPARα agonist), mimics-NC, miR-668, mimics-NC + TGF-β1, miR-668 + TGF-β1, miR-668 + TGF-β1 + fenofibrate, miR-668 + TGF-β1 + GW6471 (PPARα inhibitor), mimics-NC + TGF-β1 + fenofibrate, and mimics-NC + TGF-β1 + GW6471 groups. The pathological changes in the renal tissues were observed by hematoxylin-eosin (HE) and Masson staining. The expression of PPARα, PGC-1α, miR-668, E-cadherin, Collagen III (Col III), and α-SMA in the renal tissues or HK-2 cells was detected by western blot, immunohistochemical analyses or real-time quantitative polymerase chain reaction. The regulatory effect of miR-668 on PPARα was verified by dual-luciferase reporter assay. RESULTS: The expression of PPARα and PGC-1α decreased in UUO mice and TGF-β1-induced HK-2 cells, which was improved by fenofibrate. Compared to the non-transfected group, in TGF-β1-stimulated HK-2 cells, the expression of E-cadherin, PPARα and PGC-1α increased and the expression of Col III and α-SMA decreased in the miR-668-transfected group. The dual-luciferase reporter assay indicated the regulatory effect of hsa-mir-668-3p on PPARα. CONCLUSION: MiR-668 can target PPARα and positively regulate the PPARα/PGC-1α pathway to alleviate renal fibrosis.