NCOA4-mediated ferritinophagy modulates colitis-associated ferroptosis in intestinal epithelial cells and mucosal repair

Ferroptosis in intestinal epithelial cells (IECs) acts as a crucial mechanism driving intestinal mucosal injuries and inflammatory reactions in colitis. Nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy, a primary pathway for intracellular iron storage, takes part in regulating ferroptosis. Nevertheless, it is yet unknown whether ferritinophagy plays a role in ferroptosis of IECs in colitis. Hence, this experiment used dextran sulfate sodium salt (DSS) to establish an inflammation model with NCM460 cells and an animal model of colitis to discover the role of ferritinophagy in ferroptosis in IECs and colonic mucosal inflammatory damage. DSS induced ferroptosis in IECs, presenting as significantly increased contents of Fe2+, reactive oxygen species (ROS), and malondialdehyde (MDA), decreased protein expression of glutathione peroxidase 4 (GPX4), and increased expression of cyclooxygenase-2 (COX2) (all P<0.05). Moreover, administration of ferroptosis inhibitor liproxstatin-1 and autophagy inhibitor methyladenine (3-MA) ameliorated colonic tissue damage in the animal model of colitis, reducing the disease activity index (DAI), colon macroscopic damage index (CMDI), and pathological score, as well as the serum contents of mucosal permeability markers diamine oxidase (DAO) and D-lactic acid (D-LA) (all P<0.05). Further, knockdown of NCOA4 downregulated the expression of microtubule-associated protein light chain 3 (LC3) and autophagy-related protein 5 (ATG5) proteins, upregulated the expression of ferritin heavy chain 1 (FTH1), inhibited ferritinophagy, and decreased ferroptosis in IECs induced by DSS, thus ameliorating colonic inflammatory damage and mucosal permeability (all P<0.05). On the contrary, overexpression of NCOA4 encouraged ferritinophagy and aggravated ferroptosis in IECs and intestinal damage. This study provided evidence supporting that NCOA4-mediated ferritinophagy participates in modulating colitis-related ferroptosis in IECs, and suppressing ferritinophagy protects IECs and promotes colonic mucosal repair.