Fibroblast-specificdeletion exacerbates IBD via lipid peroxidation.

Abstract

Broad antioxidant strategies in inflammatory bowel disease (IBD) have had limited success, likely because they indiscriminately quench both harmful and physiological reactive oxygen species. In our recent work, we demonstrated that fibroblast-specific overexpression of acyl-CoA synthetase long-chain family member 4 reprogrammed lipid metabolism and sensitized adjacent epithelial cells to ferroptosis in IBD models, pointing to heterocellular lipid cross talk as a driver of epithelial injury. Building on that insight, here we test the hypothesis that fibroblast glutathione peroxidase 4 (GPX4), a key enzyme detoxifying lipid hydroperoxides, is critical in restraining fibroblast-mediated lipid peroxidation and consequent epithelial ferroptosis during colitis. We generated tamoxifen-inducible fibroblast-specific GPX4 knockout mice and subjected them to acute dextran sulfate sodium (DSS) colitis. Fibroblast-specific GPX4 deletion did not alter basal colon morphology but significantly aggravated DSS-induced injury. It increased histological scores and led to greater weight loss and colon shortening compared with littermate control mice. In vitro, GPX4-deficient fibroblasts exhibited elevated lipid peroxidation in response to ferroptosis inducers, reversible by liproxstatin-1. Critically, liproxstatin-1 treatment rescued colitis severity in fibroblast-GPX4-deficient animals, restoring colon length, weight loss, and histologic injury. Together, these findings identify fibroblast GPX4 as a gatekeeper that limits stromal lipid peroxidation and suppresses epithelial ferroptosis under inflammatory stress. Targeting fibroblast-mediated lipid peroxidation may offer a refined therapeutic axis in IBD.Fibroblast-specific GPX4 deletion promotes IBD progression. Lipid peroxidation could be a potential therapeutic target of IBD.