Gut Microbiota–Derived Tryptophan Indole Metabolites Ameliorate Collagen‐Induced Arthritis in Mice Via Aryl Hydrocarbon Receptor Activation
Authors' conclusion
These findings indicate that tryptophan indole metabolites may play a negative regulatory role in the progression of RA by affecting Treg cell development and intestinal gut barrier function.
Study context
- Population
- Individuals at high risk for rheumatoid arthritis (RA), patients with established RA and healthy individuals; Fecal microbiota transplantation (FMT) and collagen-induced arthritis (CIA) mouse models
- Participants
- 53 / 30 / 38
- Comparison
- PreRA vs established RA vs healthy individuals (metabolomics); tryptophan indole metabolites ILA and IAA in CIA mice
- PreRAn = 53
- RAn = 30
- Healthyn = 38reference
Methodological detailsmetabolomics, FMT and CIA mouse models
- Metabolomics
- FMT and CIA mouse models
Main finding
As reported in the abstract
- Dysregulated tryptophan metabolism in RA and PreRA and in FMT mice: shift toward kynurenine pathway, reduced serotonin and indole pathway activity
- ILA and IAA significantly alleviated arthritis in CIA mice by expanding Treg cells via the classical AhR-ARNT-XRE signalling pathway
- ILA repaired the leaking gut by increasing Zo-1 and occludin expression in Caco-2 cells, blocked by aryl hydrocarbon receptor (AhR) antagonist CH223191
- CH223191 significantly reversed the improving effects of ILA and IAA on arthritis in mice
Original publication
Gut Microbiota–Derived Tryptophan Indole Metabolites Ameliorate Collagen‐Induced Arthritis in Mice Via Aryl Hydrocarbon Receptor Activation. Arthritis Rheumatol. Published 18 February 2026. doi:10.
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