Ferroptosis as a mediator of gut microbiota-driven inflammatory bowel disease: Evidence from genetic analyses

Gut microbiota dysbiosis is increasingly recognized as a contributor to inflammatory bowel disease (IBD), yet causal relationships and underlying mechanisms remain unclear. Ferroptosis, an iron-dependent form of regulated cell death, plays a key role in epithelial barrier damage and inflammation. This study aimed to determine whether specific gut microbial taxa are causally associated with IBD and whether ferroptosis-related genes mediate this association using Mendelian randomization (MR). Two-sample MR and mediation MR analyses were performed using genome-wide association study summary data from the FinnGen consortium (IBD), the genome-wide association study catalog (473 gut microbial taxa), and the deCODE database (ferroptosis-related genes). Instrumental variables were selected with thresholds of P < 1 × 10-6 for microbes and P < 5 × 10-8 for traits, and linkage disequilibrium clumping (r2 < 0.001) was applied. Twenty-three microbial taxa showed significant causal associations with IBD (e.g., Chromatiales, OR = 0.51; Acetobacterales, OR = 2.61). Several ferroptosis-related genes were linked to IBD risk (e.g., GPX4, STAT3, IDO1). Mediation MR revealed that genes such as MUC1, IDO1, and ADAM23 partially mediated microbial effects on IBD, with mediation proportions up to 7.6%. This study provides novel genetic evidence supporting a gut microbiota-ferroptosis-IBD axis. Ferroptosis-related pathways may partially mediate microbial effects on IBD pathogenesis and represent promising targets for future therapeutic interventions.