Indole dysbiosis and mucosal inflammation.

Abstract

The inflammatory bowel diseases (IBD) coincide with shifts in the composition of the microbiota. Since the gastrointestinal (GI) epithelium is anatomically positioned to provide a selective barrier between the microbiota and host lamina propria, this barrier is essential for intestinal homeostasis. Decades-old studies have appreciated that byproducts of the microbiota provide an essential communication network to the host. More recent work has identified microbial-derived metabolites that support multiple functions within the GI mucosa. One such family of metabolites are the indoles, tryptophan-derived molecules that signal within the microbiota and importantly, provide anti-inflammatory properties within the host mucosa. Here, we review the topic of indole production and signaling in the healthy and diseased mucosa.