Gut microbiota-related bile acid metabolism-FXR/TGR5 axis impacts the response to anti-α4β7-integrin therapy in humanized mice with colitis

The gut microbiota and bile acid metabolism are key determinants of the response of inflammatory bowel disease to biologic therapy. However, the molecular mechanisms underlying the interactions between the response to anti-α4β7-integrin therapy and the gut microbiota and bile acid metabolism remain unknown. In this research, we investigated the role of gut microbiota-related bile acid metabolism on the response to anti-α4β7-integrin therapy in a humanized immune system mouse model with colitis induced by 2,4,6-trinitrobenzene sulfonic acid. We found that anti-α4β7-integrin significantly mitigated intestinal inflammation, pathological symptoms, and gut barrier disruption in remission-achieving colitis mice. Whole-genome shotgun metagenomic sequencing demonstrated that employing baseline microbiome profiles to predict remission and the treatment response was a promising strategy. Antibiotic-mediated gut microbiota depletion and fecal microbiome transplantation revealed that the baseline gut microbiota contained common microbes with anti-inflammatory effects and reduced mucosal barrier damage, improving the treatment response. Targeted metabolomics analysis illustrated that bile acids associated with microbial diversity were involved in colitis remission. Furthermore, the activation effects of the microbiome and bile acids on FXR and TGR5 were evaluated in colitis mice and Caco-2 cells. The findings revealed that the production of gastrointestinal bile acids, particularly CDCA and LCA, further directly promoted the stimulation of FXR and TGR5, significantly improving gut barrier function and suppressing the inflammatory process. Taken together, gut microbiota-related bile acid metabolism-FXR/TGR5 axis may be a potential mechanism for impacting the response to anti-α4β7-integrin in experimental colitis. Thus, our research provides novel insights into the treatment response in inflammatory bowel disease.