Host regulatory mechanism that shapes the neonatal microbiome published by the AG Hornef in Nature

Members of the AG Hornef identified a regulatory circuit of the murine host's intestinal epithelium that influences early colonization by commensal bacteria. They demonstrate age-dependent expression of the flagellin receptor Toll-like receptor (TLR)5 at the intestinal epithelium. Through activation of a local antimicrobial response, TLR5 counter-selects colonization by flagellated bacteria shaping the bacterial composition of the neonatal enteric microbiota. Surprisingly, the early shaped microbiota composition remains stable over a prolonged time period, although epithelial TLR5 expression is restricted to the nonatal period. This highlights the critical importance of the neonatal period for host-microbial homeostasis.