Role Of MROS-TXNIP-NLRP3 Signal Pathway In Mediating Acute Kidney Injury

Background Acute kidney injury(AKI) is a common and serious clinical disorder. Renal ischemia/reperfusion (I/R), a major cause of AKI, is characterized by renal tubular epithelial injury and interstitial inflammation. Recent studies suggested that mitochondrial dysfunction and NLRP3 inflammasome activation are important drivers of AKI. In this study, we investigated whether activation of the NLRP3 inflammasome is involved in ischemic AKI and the underlying mechanisms of NLRP3 inflammasome activation.Methods C57BL/6J wild type(WT) and NLRP3 gene knockout (NLRP3 KO) mice were randomly divided into control group and I/R group respectively. The mice from I/R group were subjected to 30min ischemia and 1,3 or 7 days reperfusion. The mice were then sacrificed and blood or tissues were harvested at days 1,3 or 7 days after I/R injury. In vitro study, tubular epithelial cells (HK-2 cells) were cultured for 1,3,6 and 9 hours with hypoxia/hypoglycemic plus 2 hours normoxia/normal glucose incubation. The protein expression of molecules involved in NLRP3 inflammasome pathway and TXNIP were examined by Western Blot and immunoprecipitation. Moreover, the silencing of the NLRP3 and TXNIP gene, or MitoTEMPO, a mitochondria-targeted antioxidant, was used as intervention.Results In this study, we established an I/R induced AKI model characterized by tubular necrosis and excessive mROS production. The renal expression of NLRP3 inflammasome, caspace-1, IL-1? and IL-18 were significantly increased in WT I/R group. However, kidney dysfunction was attenuated obviously by NLRP3 gene knockout. In the vitro study, oxygen-glucose deprivation injury time dependenly increased the expression levels of NLRP3 inflammasome axis. Moreover, we found that damaged cells had increased recruitment of TXNIP to mitochondria compared to that of control cells. Inhibition of TXNIP attenuated the assembly of the NLRP3 inflammasome complex. Pretreatment with MitoTEMPO significantly prevented the hypoxia-induced binding of TXNIP and NLRP3 and inhibited the NLRP3 inflammasome activation.Conclusion Excessive mROS production in ischemia AKI activates NLRP3 inflammasome by inducing TXNIP to bind with NLRP3, suggesting blocked the mROS-TXNIP-NLRP3 signal pathway will be a novel strategy for the treatment of AKI.