Circadian rhythms in microbiota gut-brain axis

Tryptophan has an important role in microbiota-gut-brain axis signaling and is a precursor of key molecules involved in circadian rhythmicity and in stress-related disorders. Stress alters microbiota-gut-brain axis signalling, including the bioactives produced from tryptophan although there is an incomplete understanding for the key players and factors shaping host-microbe dialogue during acute stress exposures. Tryptophan can be metabolised both by gut microbiota and the host in a circadian manner, to generate a wide range of molecules across the day. Microbial tryptophan breakdown can have important implications for gut barrier function and permeability by generating Aryl Hydrocarbon Receptor (AhR) ligands. The aim of this project was to understand how the expression of genes implicated in gut barrier function oscillate across the day depending on microbial status, both at baseline and following an acute stressor.