Molecular mechanism of miR-382 in the pathogenesis of renal tubulointerstitial fibrosis / 中华肾脏病杂志

ABSTRACT

Objective To investigate the roles of microRNA-382 (miR-382) in the pathogenesis of renal tubulointerstitial fibrosis (TIF).Methods Human kidney epithelial cells (HK2)transfected with miR-382 inhibitor (antagomiR-382) were used to examine the effect of miR-382 abundance on cell polarity,as well as to test the complementary relationship between miR-382 and its predicted target gene heat shock protein 60 (HSPD1),which was further verified by 3'-untranslated region luciferase assay and site-directed mutagenesis.The role of miR-382 played in the development of renal interstitial fibrosis and redox regulation was examined in a mouse unilateral ureteral obstruction (UUO) model.Locked nucleic acid (LAN)-modified anti-miR-382 was intravenous delivered via tail vein 30 min prior to UUO,and repeated the dosage 24 h after the surgery.For clinical verification,renal biopsy specimens from 12 IgA nephropathy (IgAN) patients were collected,6 patients with moderate to severe TIF and 6 patients without TIF.The relative abundance of miR-382 and HSPD1 protein was analyzed by using in situ hybridization and immunohistochemistry.Results HSPD1 was confirmed to be a new,direct target gene of miR-382 by in vitro 3'-untranslated region luciferase assay and sitedirected mutagenesis.The development of epithelial transition in HK2 cells was accompanied with upregulation of miR-382 [(6.54±0.96) vs (1.12±0.26),P ＜ 0.05].Blocking the expression of miR-382 could reversed the progression of epithelial transition partially.In UUO mice the abundance of miR-382 was up-regulated [(6.89 ± 2.47) vs (1.00±0.42),P ＜ 0.01] while HSPD1 and Trx were downregulated compared with the sham group.Down-regulation of miR-382 was associated with significant decrease in TIF,but increase in HSPD1 and thioredoxin protein compared with UUO group [HSPD1:(0.34±0.10) vs (0.14±0.05);Trx:(0.79±0.18) vs (0.36±0.16);all P ＜ 0.05].The expression of miR-382 was up-regulated and HSPD1 was significantly down-regulated in IgAN patients with TIF.Conclusions miR-382 play an important role in renal tubulointerstitial fibrosis in human and mice.HSPD1 is one of the target genes of miR-382.The down-regulation of HSPD1 and the decrease ability of anti-oxidative stress may be the important mechanism of miR-382 involved in renal tubulointerstitial fibrosis.