Effects of stress on the mucus-microbial interactions in the gut.

Stress shows both direct- and indirect-effects on the functions of the gastrointestinal tract, in particular on the mucus physiology and the composition of microbiota. Mucus mainly consists of heavily glycosylated proteins called mucins, which are secreted by goblet cells. The gut mucus layer is a pivotal part of the intestinal protection and colonized by commensal microbes, essential for the development and health of the host. There is a symbiotic interaction between intestinal microbiota and the host cells. On the one hand, mucus provides nutrients for the growth and adhesion of microbes; on the other hand, mucin-degrading bacteria generate energy sources for the host epithelium. However, the mucus-microbial interaction has rarely been considered in the context of stress exposure. Therefore, this paper principally reviews the effects of stress on both mucus secretion and gut microbiota and is hoped to provide a new perspective for future study.