Cytochrome P450 Cyp2s1 regulation of the intestinal metabolome and microbiome.

Xenobiotics and environmental factors implicated in inflammatory bowel disease (IBD) are metabolized by cytochrome P450 enzymes. Cyp2s1, an orphan member of this family, is highly expressed in the intestine, yet its role remains unclear. Here, we investigated the function of Cyp2s1 in intestinal homeostasis and inflammation by combining untargeted metabolomics, microbiome sequencing, colitis mouse models, and IBD patient biopsies. We observed markedly reduced Cyp2s1 expression in patients with active IBD and in multiple colitis models. Single-cell RNA sequencing identified abundant Cyp2s1 expression in the intestinal epithelium. Importantly, the AhR agonist, 6-Formylindolo[3,2-b]carbazole (FICZ) robustly induced Cyp2s1 expression in mouse colon organoids and Caco-2 cells. Mechanistically, metabolomic analysis of intestinal epithelial cells and feces from mice overexpressing or lacking Cyp2s1 revealed altered metabolite profiles. The SCENITH assay further confirmed disrupted fatty acid oxidation capacity in colonocytes of Cyp2s1-transgenic mice. Moreover, shotgun microbiome sequencing revealed reduced microbial richness and expansion of A. muciniphila in Cyp2s1-overexpressing mice. Consequently, upon DSS challenge, these mice developed exacerbated colitis symptoms compared to controls. Our findings identify Cyp2s1 as a novel AhR-inducible gene critical for modulating the intestinal metabolome and microbiome, suggesting that targeting AhR activity or Cyp2s1 itself may offer therapeutic strategies for IBD.