Glycobiology of Host‐Microbe Interactions in the Gut

Abstract

The gastrointestinal (GI) tract is colonised by trillions of bacteria collectively known as the ‘gut microbiota’ which have a profound impact on human health. Bacterial adhesion is a critical step for colonization of the host. Cell surface proteins (adhesins or lectins) mediate attachment to the host and initiate colonization by interacting with host proteins or glycoconjugates. However, in contrast to pathogens, the molecular basis for adhesion of commensal bacteria or probiotics to the gut remain poorly defined.The mucus layer covering the GI tract is the first point contact between the gut microbiota and the host. There is an emerging paradigm that mucin glycans are key molecular determinants of gut homeostasis by providing binding sites and/or nutrients to the bacteria which have adapted to the mucosal environment.Here we provide structural and functional insights into how gut bacteria adapt to the GI tract by focusing on the adhesion strategies of two inhabitant species of the GI tract, Ruminococcus gnavus1,2 and Lactobacillus reuter,3,4,5. The presentation will discuss relevant mechanistic insights into the nature, structure and function of bacterial adhesins involved in the interaction between these gut symbionts and the host glycoconjugates. Our results showed that adhesion strategy is species‐ and strain‐specific and occurs via specialised mucus‐binding proteins or carbohydrate‐binding modules. Sialic acid, a terminal epitope in intestinal mucins, plays a critical role in mediating bacterial tropism along the GI tract.Exploring the molecular basis of adhesion by resident species of the gut microbiota is important for the design of microbiota‐targeted strategies to restore gut health.Support or Funding InformationThe work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC), under the Institute Strategic Programme Grant for Gut Microbes and Health (BB/R012490/1).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.