Ferroptosis triggered by STAT1-IRF1-ACSL4 pathway was involved in radiation-induced intestinal injury

Radiation-induced intestinal injury (RIII), a common gastrointestinal complication caused by radiotherapy on pelvic, abdominal and retroperitoneal tumors, seriously affects the life quality of patients and may result in termination of radiotherapy. At present, the pathogenesis of RIII has not been fully understood. Herein, we demonstrated that ferroptosis played a critical role in RIII occurrence. The RNA sequencing analysis strongly hinted ferroptosis was involved in RIII mice. In line with this, the levels of 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA), markers of lipid peroxidation, remarkably increased in RIII mice. And the ferroptosis inhibitor, Ferrostatin-1 (Fer-1), improved the mice survival and alleviated intestinal fibrosis in vivo. Moreover, our results revealed that arachidonic acid (AA) enhanced ferroptosis in cultured intestinal epithelial cells (IECs) and organoids in vitro after irradiation, and AA gavage aggravated RIII in mice. Mechanistic studies revealed the level of ACSL4 protein significantly increased in mouse jejunums and IECs after irradiation. Radiation-induced ferroptosis in IECs was also prevented following ACSL4 knockdown or with the function inhibitor of ACSL4. Furthermore, we found that transcription of ACSL4 induced by irradiation was regulated by STAT1/IRF1 axis, and AMPK activation triggered by AA negatively regulated radiation-induced ferroptosis. Taken together, our results suggest that ferroptosis mediates RIII and reducing dietary AA intake as well as targeting the STAT1-IRF1-ACSL4 axis or AMPK may be the potential approaches to alleviate RIII.

Automated summary

Radiation-induced intestinal injury (RIII) is a common complication of radiotherapy, seriously affecting patients' quality of life. This study found that ferroptosis plays a critical role in RIII, with increased levels of lipid peroxidation markers. In vivo experiments demonstrated that the ferroptosis inhibitor improved the survival rate and alleviated intestinal fibrosis in mice. It was also found that arachidonic acid enhanced ferroptosis in cultured intestinal epithelial cells and aggravated RIII. Mechanistic studies revealed that the level of ACSL4 protein increased after irradiation, regulated by the STAT1/IRF1 axis, while AMPK activation triggered by AA negatively regulated radiation-induced ferroptosis.