AHR and colitis: In DSS-induced colitis, B. bifidum metabolite indole-3-lactic acid regulates aryl hydrocarbon receptor (AHR)/NF-E2-related factor 2 (NRF2)/NOD-like receptor thermal protein domain associated protein 3 (NLRP3) signaling pathway, thereby upregulating tight junction proteins and protecting intestinal epithelial barrier function (25).