Interactions of commensal and pathogenic microorganisms with the intestinal mucosal barrier

Abstract

The intestinal mucosal barrier is composed of epithelial cells that are protected by an overlying host-secreted mucous layer and functions as the first line of defence against pathogenic and non-pathogenic microorganisms. Some microorganisms have evolved strategies to either survive in the mucosal barrier or circumvent it to establish infection. In this Review, we discuss the current state of knowledge of the complex interactions of commensal microorganisms with the intestinal mucosal barrier, and we discuss strategies used by pathogenic microorganisms to establish infection by either exploiting different epithelial cell lineages or disrupting the mucous layer, as well as the role of defects in mucus production in chronic disease.

Phellinus linteus polysaccharide extract improves insulin resistance by regulating gut microbiota composition

“…3 Administration of Met or dietary polysaccharides can alleviate diabetes symptoms, and the mechanism underlying this effect involves regulation of intestinal microbes. 40 In the present study, PLPE treatment enhanced levels of many bacteria, including Lachnospiraceae-NK4A136, Lachnospiraceae-UCG-006, Roseburia, Prevotella9, Blautia, Ruminiclostridium-9, Eubacterium_xylanophilum, Anaerotruncus, and Oscillibacter, and effectively reversed intestinal microbial imbalance. Fiber polysaccharides are hydrolyzed by thousands of carbohydrate-active enzymes (CAZymes) produced by host bacteria, and release liberated sugars.…”

“…Fiber polysaccharides are hydrolyzed by thousands of carbohydrate-active enzymes (CAZymes) produced by host bacteria, and release liberated sugars. 40 In the present study, PLPE treatment enhanced levels of many bacteria, including Lachnospiraceae-NK4A136, Lachnospiraceae-UCG-006, Roseburia, Prevotella9, Blautia, Ruminiclostridium-9, Eubacterium_xylanophilum, Anaerotruncus, and Oscillibacter, and effectively reversed intestinal microbial imbalance. A recent study by Vanegas et al 41 showed that enrichment of Lachnospiraceae-NK4A136, Lachnospiraceae-UCG-006, and Roseburia by administration of fiber polysaccharides promoted the ability of these F I G U R E 6 (Continued) bacteria to decompose fiber polysaccharides to produce acetate and butyrate, and to reduce inflammation.…”

Immunology‐Guided Biomaterial Design for Mucosal Cancer Vaccines

“…Mucous secretions are composed of mucins, produced in the epithelium by goblet cells. In the mucosae, three main functions of mucous secretions can be highlighted: protection from desiccation, lubrication, and protection from foreign particles (e.g., microorganisms) . The latter function is relevant for cancer vaccine design using biomaterials, as mucus will vastly affect particle motility and penetrance …”

“…In the mucosae, three main functions of mucous secretions can be highlighted: protection from desiccation, lubrication, and protection from foreign particles (e.g., microorganisms). [22,23] The latter function is relevant for cancer vaccine design using biomaterials, as mucus will vastly affect particle motility and penetrance. [22,24] The lamina propria contains components that include lymphatic vasculature, blood vasculature, and different populations of leukocytes.…”

Enterohaemorrhagic Escherichia coli activates nitrate respiration to benefit from the inflammatory response for acceleration of infection

“…The increase in nitrate by the inflammatory response has been shown to stimulate the growth of the commensal bacterium E. coli, which is dependent on nitrate respiratory activity [16]. Because infection of epithelial cells with pathogens induces an inflammatory response [17], the initial infection of even a small number of pathogens could accelerate 4 the growth of pathogens through an increase in nitrate concentration.…”