Heat stress-induced intestinal epithelial cells necroptosis via TLR3-TRIF-RIP3 pathway was dependent on p53

Background: Heatstroke is a life-threatening disease. Present study was aimed to investigate the mechanism in heat induced intestinal epithelial cell death.Method: Heat stress in vitro model was established on IEC cells with 42 & DEG;C for 2 h. Caspase-8 inhibitor, Caspase-3 inhibitor, RIP3 inhibitor, TLR3 agonist, poly(I:C) and p53 knockdown were used to determine the signaling pathway. Heatstroke in vivo model was established on C57BL/6 mice, with a temperature of 35.5 & DEG;C & PLUSMN;0.5 & DEG;C and a relative humidity of 60% & PLUSMN; 5%. The intestine necroptosis and inflammatory cytokines were measured. Pifithrin & alpha; (3 mg/kg) and p53 knockout mice were used to evaluate the role of p53.Results: Heat stress-induced reduction of cell viability was remarkable reversed by RIP3 inhibitor. Heat stress induced upregulation of TLR3 and facilitate the formation of TRIF-RIP3 complex. The heat stress induced upregulation of RIP3 and p-RIP3 were normalized by the deletion of p53. Meanwhile, p53 knockout decreased TLR3 expression and blocked the formation of TLR3-TRIF complex. The deletion of p53 blocked the decreased cell viability and restored the activation of RIP3-MLKL signaling after heat stress, however, which were abolished by re-expression of p53 via Tp53 OE. Increased the expression of TLR3 in the p53-deficient cells could not affect the heat stress induced necrotic cell death, which suggests that heat stress induced necroptosis via TLR3-TRIFRIP3 signaling pathway is dependent on p53.Conclusion: Heat stress promoted p53 phosphorylation, then upregulated TLR3 and enhanced the interaction of TRIF-RIP3, which would activate the RIP3-MLKL signaling pathway to mediate necroptosis in intestinal epithelial cells.

Automated summary

This study aimed to investigate the mechanism of heat-induced intestinal epithelial cell death. The results showed that heat stress upregulated TLR3 and facilitated the formation of TRIF-RIP3 complex, which activated the RIP3-MLKL signaling pathway, leading to necroptosis in intestinal epithelial cells. In addition, heat stress promoted the phosphorylation of p53 and increased TLR3 expression. Thus, heat stress induced necroptosis in intestinal epithelial cells through the p53-TLR3-TRIF-RIP3-MLKL signaling pathway.