Gut microbes influence emotional symptoms through a brain signaling pathway involving the hippocampus

In IBS models, reduced gut microbe-derived indole was linked to emotional symptoms through hippocampal AhR signaling in the ventral dentate gyrus.

This mechanistic preclinical study combined IBS patient microbiome observations with mouse, transplantation, supplementation, chemogenetic, and agonist experiments implicating an Alistipes shahii-tryptophanase-indole-AhR-vDG pathway.

The causal rescue data come from mouse models, while the human evidence is observational and limited to reduced Alistipes shahii and indole in IBS patients.