P53 transcribes  GSDMD to induce delayed pyroptosis in radiation-induced intestinal injury

Abstract

Background radiation-induced intestinal injury (RIII) is an important cause of death in nuclear accidents and common complication after radiotherapy in patients with pelvic, abdominal, or retroperitoneal tumors. Up to now there is no effective means to prevent or treat RIII due to its complex mechanism, in which the death of intestinal cells is the main reason. Recently, GSDMD-mediated pyroptosis was identified as an important type of cell death and play a role in many diseases. However, the effect of pyroptosis on RIII is still unclear. Method using GSDMD knockout mice, the role of pyroptosis in the RIII was investigated. By detecting the release of LDH, expression of GSDMD, Caspase-11, Caspase-1 and absorption rate of SYTOX Green, the pyroptosis of radiated Mode-k cells was determined, simultaneously the common pyroptosis induced by LPS was conducted as positive control. Further, the upstream of GSDMD were screened by predictive analysis of transcription factors combing RNA-seq. Results we showed that GSDMD-mediated pyroptosis is involved in the process of RIII, and unexpectedly found that radiation induced a delayed pyroptosis that is substantially different from common pyroptosis induced by such as LPS. Further investigation revealed that radiation-induced DNA damage up-regulated the expression of P53, which subsequently transcribes GSDMD. In addition, the up-regulated GSDMD led to pyroptosis simultaneously promoting Ca2+ influx that afterwards enhanced apoptosis induced by radiation. Finally, targeting GSDMD, disulfiram displayed a potential protection for RIII. Conclusion radiation could induce delayed pyroptosis in the intestinal epithelial cell that is greatly different from common pyroptosis. During that process, GSDMD was cleaved and had inducible high expression which was mainly mediated by P53 transcription.