4-HDHA, a DHA metabolite screened by targeted lipidomic, alleviates DSS-induced colitis by inhibiting apoptosis and reducing inflammation

Ulcerative colitis (UC) remains a global health challenge, with current therapeutic strategies limited by efficacy and adverse effects. In this study, we observed that the lipid peroxide scavenger Liproxstatin-1 unexpectedly promoted TNF-α-induced apoptosis in HT-29 cells and murine colonic organoids, in contrast to the protective effects previously reported for typical peroxide scavengers in UC. To identify alternative protective metabolites, we performed targeted lipidomics, which revealed 4-hydroxy-docosahexaenoic acid (4-HDHA), a metabolite of DHA, as a candidate with pronounced anti-apoptotic activity in vitro and ex vivo. Intraperitoneal administration of 4-HDHA effectively ameliorated DSS-induced colitis in mice. RNA sequencing indicated significant enrichment of the PPAR signaling pathway following 4-HDHA treatment. Dual-luciferase reporter assays confirmed that 4-HDHA enhances PPARγ transcriptional activity, while pharmacological inhibition with GW9662 abrogated its therapeutic effects. Furthermore, 4-HDHA suppressed NF-κB signaling and apoptosis via PPARγ activation. Collectively, these findings demonstrate that 4-HDHA, identified through targeted lipidomics, attenuates DSS-induced colitis by reducing apoptosis and inflammation through PPARγ activation, highlighting its potential as a promising therapeutic agent for UC.