Pyroptosis is an exceptional mode of inflammation and programmed cell death involved in inflammasomes and Caspase-1 activation and inflammatory cytokines releasing. Our goal is to explore whether uranium (U)-intoxication could induce NRK-52E cells pyroptosis in vitro and its underlying molecular mechanism. Rat NRK-52E cells were intoxicated with U concentrations (400-500 μM) for 24 h. The results indicate that the cells showed characteristic features of pyroptosis, which were identified through augmented NLRP3 and cleaved Caspase-1 proteins expression, GSDMD mRNA level, mature interleukin IL-18 and IL-1β contents, LDH leakage, and the number of double-positive cells. But, administration of glycine (an inhibitor of pyroptosis) effectively attenuated U-induced pyroptosis, LDH releasing and cytotoxicity. Pretreatment of CRID3 (an inhibitor of NLRP3 inflammasome) evidently abrogated NLRP3 and cleaved Caspase-1 proteins and GSDMD mRNA expression which all were up-regulated by U exposure. Simultaneously, CRID3 significantly reversed U-increased pyroptosis rate and active interleukin IL-18 and IL-1β contents. NAC application (an ROS scavenger) effectively decreased U-increased ROS content and NLRP3 expression and restored U-induced pyroptosis. Taken together, our results suggest that U-treatment can trigger NRK-52E cells pyroptosis which is involvement of ROS/NLRP3/Caspase-1 pathway. Targeting ROS/NLRP3/Caspase-1-mediated pyroptosis may be a novel approach for attenuating U nephrotoxicity.
Keywords: NLRP3; Pyroptosis; nephrotoxicity; oxidative stress; uranium.