Rapidly induced fucosylation of intestinal epithelium sustains host-commensal symbiosis during sickness.. mouse gut metagenome

Systemic infection induces conserved physiological responses that include both resistance and ‘tolerance of infection’ mechanisms. Among these responses, temporary anorexia associated with an infection is often beneficial. It poses, however, a problem for the trillions of microbes residing in the gastrointestinal tract, as they also experience reduced substrate availability. We hypothesized that under anorectic conditions caused by infection, the host might activate protective mechanisms to support the gut microbiota during the acute phase of the disease. Here, we report that systemic exposure to Toll-like receptor (TLR) ligands causes rapid α1,2-fucosylation of the small intestine epithelial cells (IEC). The process requires sensing of TLR agonists and production of IL-23 by dendritic cells, activation of innate lymphoid cells and expression of α1,2-Fucosyltransferase-2 (Fut2) by IL-22-stimulated IECs. Fucosylated proteins are shed into the lumen and fucose is utilized by microbiota, as shown using reporter bacteria and by transcriptional profiling of the gut microbiome. Fucosylation also reduces the expression of bacterial virulence genes within the commensal gut microbiome and improves host tolerance of the mild pathogen Citrobacter rodentium. Thus, rapid IEC fucosylation appears to be a protective mechanism that utilizes the host’s resources to maintain host-microbial interactions during pathogen-induced stress. Overall design: RNA-Seq analysis of the murine gut microbiome following LPS exposure. Fut2-/- (B6.129X1-Fut2tm1Sdo/J) mice were backcrossed greater than 7 generations to BALB/c. Fut2-/- (KO) and Fut2+/- (Het) animals were analyzed.