Farnesoid X receptor activation by the novel agonist TC-100 (3α, 7α, 11β-Trihydroxy-6α-ethyl-5β-cholan-24-oic Acid) preserves the intestinal barrier integrity and promotes intestinal microbial reshaping in a mouse model of obstructed bile acid flow

The intestinal tract hosts the gut microbiota (GM), actively shaping health. Bile acids(BAs) are both digestive and signaling molecules acting as hormones via the activation of farnesoid X receptor (FXR). Obstruction of bile flow initiates a cascade of pathological events ultimately leading to intestinal mucosal injury. Administration of BAs in models of obstructed bile flow counteracts these detrimental effects. Objective of this study was to investigate the effects of the novel FXR agonist 3α, 7α, 11β-Trihydroxy-6α-ethyl-5β-cholan-24-oic Acid (TC-100) on intestinal mucosa integrity and cecal microbiome composition after surgical bile duct ligation (BDL), a rodent model causing bile flow obstruction. Pharmacological FXR activation was accomplished by daily oral gavage with TC-100 for 5 days. 2 days after treatment initiation, BDL was performed. BAs measurement was carried out and the 16S rDNA (V5-V6 hyper-variable regions) extracted from the cecal content was sequenced. TC-100 activates Fxr in the gut-liver axis and this translated into a significant reduction of serum and bile BA pool size with a shift to a more hydrophilic composition, while signs of intestinal mucosal damage were prevented. Firmicutes:Bacteroidota ratio progressively increased from Sham Operated (SO) mice to TC-100-treated mice. LEfSe analysis showed that Verrucomicrobia, and particularly Akkermansia muciniphila (Amuc) increasingly recognized for improving gut homeostasis and immune functions, were strongly associated to TC-100-treated mice. Intriguingly, Amuc abundance was also negatively associated to cholic acid levels. Collectively, these data indicate that intestinal FXR activation by TC-100 prevents early signs of intestinal mucosal damage by modulating BA homeostasis and GM composition.