Osteoarthritis treatment via the GLP-1–mediated gut-joint axis targets intestinal FXR signaling

Whether a gut-joint axis exists to regulate osteoarthritis is unknown. In two independent cohorts, we identified altered microbial bile acid metabolism with reduced glycoursodeoxycholic acid (GUDCA) in osteoarthritis. Suppressing farnesoid X receptor (FXR)—the receptor of GUDCA—alleviated osteoarthritis through intestine-secreted glucagon-like peptide 1 (GLP-1) in mice. GLP-1 receptor blockade attenuated these effects, whereas GLP-1 receptor activation mitigated osteoarthritis. Osteoarthritis patients exhibited a lower relative abundance of Clostridium bolteae , which promoted the formation of ursodeoxycholic acid (UDCA), a precursor of GUDCA. Treatment with C. bolteae and Food and Drug Administration–approved UDCA alleviated osteoarthritis through the gut FXR–joint GLP-1 axis in mice. UDCA use was associated with lower risk of osteoarthritis-related joint replacement in humans. These findings suggest that orchestrating the gut microbiota–GUDCA–intestinal FXR–GLP-1–joint pathway offers a potential strategy for osteoarthritis treatment.