miR-122-5p Regulates Renal Fibrosis In Vivo

The role of exogenous microRNAs (miRNAs) in renal fibrosis is poorly understood. Here, the effect of exogenous miRNAs on renal fibrosis was investigated using a renal fibrosis mouse model generated by unilateral ureteral obstruction (UUO). miRNA microarray analysis and quantitative reverse-transcription polymerase chain reaction showed that miR-122-5p was the most downregulated (0.28-fold) miRNA in the kidneys of UUO mice. The injection of an miR-122-5p mimic promoted renal fibrosis and upregulated and , whereas an miR-122-5p inhibitor suppressed renal fibrosis and downregulated and . The expression levels of fibrosis-related mRNAs, which were predicted targets of miR-122-5p, were evaluated. The expression level of , a pro-fibrotic mRNA, was upregulated by the miR-122-5p mimic, and the expression level of , an anti-fibrotic mRNA, was upregulated by the miR-122-5p inhibitor. The protein expressions of TGFBR2 and FOXO3 were confirmed by immunohistochemistry. Additionally, the expression levels of , downstream anti-fibrotic mRNAs of , were upregulated by the miR-122-5p inhibitor. These results suggest that miR-122-5p has critical roles in renal fibrosis.