Autophagy mediated FTH1 degradation activates gasdermin E dependent pyroptosis contributing to diquat induced kidney injury.

ABSTRACT

Acute kidney injury (AKI) induced by diquat (DQ) progresses rapidly, leading to high mortality, and there is no specific antidote for this chemical. Our limited knowledge of the pathogenic toxicological mechanisms of DQ has hindered the development of treatments against DQ poisoning. Pyroptosis is a form of programmed cell death and was recently identified as a novel molecular mechanism of drug-induced AKI. To explore the role of pyroptosis in HK-2 cells exposed to DQ, the plasma membrane damage of the cells was detected by LDH release assay. Western blot was performed to detect the cleavage of GSDME. Proteomics analysis was performed to explore the mechanism of DQ induced nephrotoxicity. FerroOrange probe was used to measure the intracellular Fe2+ levels. Herein, we show that DQ induces pyroptosis in HK-2 cells. Mechanistically, DQ induces the accumulation of mitochondrial ROS and initiates the cleavage of gasdermin E (GSDME) in an intrinsic mitochondrial pathway. Knockout of GSDME attenuated DQ-induced cell death. Further analysis revealed that loss of FTH1 induces Fe2+ accumulation, contributing to DQ-induced pyroptosis. Knockdown LC3B could help restore the expression of FTH1 and improve cell viability. Moreover, we found DFO, an iron chelator, could reduce cellular Fe2+ levels and inhibit pyroptosis. Collectively, these findings suggest an unrecognized mechanism for GSDME-dependent pyroptosis in DQ-induced AKI.