NCOA4-mediated ferritinophagy is involved in ionizing radiation-induced ferroptosis of intestinal epithelial cells

Hao Zhou; Ya-Li Zhou; Jiu-Ang Mao; Lin-Feng Tang; Jie Xu; Zhen-Xin Wang; Yang He; Ming Li

doi:10.1016/j.redox.2022.102413

NCOA4-mediated ferritinophagy is involved in ionizing radiation-induced ferroptosis of intestinal epithelial cells

Redox Biol. 2022 Sep:55:102413. doi: 10.1016/j.redox.2022.102413. Epub 2022 Jul 30.

Authors

Hao Zhou¹, Ya-Li Zhou², Jiu-Ang Mao³, Lin-Feng Tang¹, Jie Xu², Zhen-Xin Wang⁴, Yang He⁵, Ming Li⁶

Affiliations

¹ State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China.
² MOE Engineering Center of Hematological Disease, Jiangsu Institute of Hematology, First Affiliated Hospital of Soochow University, Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, 215006, China.
³ Department of Medical Oncology, The First Affiliated Hospital of Soochow University, Suzhou, 215006, China.
⁴ Department of Medical Oncology, The First Affiliated Hospital of Soochow University, Suzhou, 215006, China. Electronic address: zhenxw316@163.com.
⁵ MOE Engineering Center of Hematological Disease, Jiangsu Institute of Hematology, First Affiliated Hospital of Soochow University, Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, Soochow University, Suzhou, 215006, China. Electronic address: heyang1963@163.com.
⁶ State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China. Electronic address: lim1984@suda.edu.cn.

Abstract

Ferroptosis is a newly recognized form of regulated cell death that is characterized by severe lipid peroxidation initiated by iron overload and the generation of reactive oxygen species (ROS). However, the role of iron in ionizing radiation (IR)-induced intestinal injury has not been fully illustrated yet. In this study, we found that IR induced ferroptosis in intestinal epithelial cells, as indicated by the increase in intracellular iron levels and lipid peroxidation, upregulation of prostaglandin-endoperoxide synthase 2 (PTGS2) mRNA, reduced glutathione peroxidase 4 (GPX4) mRNA and glutathione (GSH) levels, and significant mitochondrial damage. In addition, the iron chelator deferoxamine (DFO) attenuated IR-induced ferroptosis and intestinal injury in vitro and in vivo. Intriguingly, pharmacological inhibition of autophagy with 3-methyladenine (3-MA) mitigated IR-induced ferritin downregulation, iron overload and ferroptosis. IR increased the levels of nuclear receptor coactivator 4 (NCOA4) mRNA and protein. NCOA4 knockdown significantly inhibited the reduction of ferritin, decreased the level of intracellular free iron, and mitigated ferroptosis induced by IR in HIEC cells, indicating that NCOA4-mediated autophagic degradation of ferritin (ferritinophagy) was required for IR-induced ferroptosis. Furthermore, cytoplasmic iron further activated mitoferrin2 (Mfrn2) on the mitochondrial membrane, which in turn increased iron transport into the mitochondria, resulting in increased ROS production and ferroptosis. In addition, mice fed with an iron-deficient diet for 3 weeks showed a significant reversal in the intestinal injury induced by abdominal IR exposure. Taken together, ferroptosis is a novel mechanism of IR-induced intestinal epithelial cytotoxicity, and is dependent on NCOA4-mediated ferritinophagy.

Keywords: Ferritinophagy; Ferroptosis; Intestinal epithelial cells; Ionizing radiation; Reactive oxygen species (ROS).