Role of OMA1 in lipopolysaccharide-induced acute kidney injury / 中华肾脏病杂志

ABSTRACT

Objective To investigate the role of OMA1 in acute kidney injury (AKI) induced by lipopolysaccharide (LPS).Methods OMA1 wild-type and knocked out mice (8 week old) were injected with 10 mg/kg body weight of LPS.The model was confirmed by testing mouse serum creatinine and blood urea nitrogen.The apoptosis in mouse kidney cortex was examined by TUNEL staining and cleaved caspase 3.In vitro,in humam kidney proximal tubular cells (HK2) were knocked down OMA1 by transfecting OMA1 shRNA,with the scramble shRNA being used as negative control of transfection.HK2 cells were cultured with 5 μg/ml of LPS for 24 hours to induce apoptosis.DAPI staining of cells and caspase-3 activity were applied to test apoptosis.The images of mitochondria in cells were obtained by transfection of mito-green plasmid and OMA1 shRNA.Western blotting was used to exam the OMA1 and Cytochrome C expressions.Resudts Compared with OMA1 KO mice,LPS induced more severe AKI of WT mice with higher Scr [(97.2±26.5) μmol/L vs (53.0±17.7) μmol/L,P ＜ 0.05] and BUN [(43.3± 13.7) mmol/L vs (29.7±7.7) mmol/L,P ＜ 0.05].Moreover,there were more apoptosis cells in kidney cortex in WT mice than in OMA1 KO mice [(75.4± 26.1)/ram2 vs (38.3± 14.4)/mm2,P＜ 0.05].About 46％ of OMA1 expressions in HK2 cells were inhibited by OMA1 shRNA transfection (P ＜ 0.05).Further,OMA1 shRNA cells with LPS stimulation had decreased mitochondria fragmentation [(29.8±10.9)％ vs (43.2±6.8)％,P ＜ 0.05],Cytochrome C release [(37.0±12.3)％ vs (76.0±26.2)％,P ＜ 0.05],and cell apoptosis [(13.2±3.9)％ vs (25.0±7.1)％,P ＜ 0.05] as compared with control cells.Conclusion Knockdown of OMA1 alleviated septic AKI through inhibition of cell apoptosis,mitochondria fragmentation,and Cytochrome C release.