Microbial Interactions with the Intestinal Epithelium and Beyond: Focusing on Immune Cell Maturation and Homeostasis
Purpose of Review
Our perception of human microbes has changed greatly in the past decade from a focus on pathogens and infections to a new world view of mutualism and coevolution of microbes and mammalian hosts. This review article seeks to explain the dynamic interactions occurring between the intestinal microbiome and the mammalian host mucosa..
Microbial metabolites influence the functions of epithelial, endothelial, and immune cells in the intestinal mucosa. Microbial metabolites like SCFAs and B complex vitamins influence macrophage differentiation and polarization, whereas microbe-derived biogenic amines such as histamine modulate the biology of the intestinal epithelium and immune responses. Aberrant bacterial lipopolysaccharide-mediated signaling may be involved in the pathogenesis of chronic intestinal inflammation and colorectal carcinogenesis.
We conclude that gut microbes (commensals and probiotics) can have profound impact on mammals by modulation of intestinal immunity and physiology and by influencing the functions of various cell types within the intestine. In addition, microbial metabolites have well-defined effects on shaping the gut epithelium, and these compounds play a key role in maintaining intestinal homeostasis. Therefore, effectively manipulating the microbiome via changes in diet and microbial composition and function may yield advances regarding diagnosis and treatment.
KeywordsMicrobes Homeostasis Intestinal epithelium Macrophage Endothelium Metabolites
This work was supported by the National Institutes of Health to J.V., including the Texas Medical Center Digestive Disease Center (P30 DK56338), National Cancer Institute (U01 CA170930), and unrestricted research support from BioGaia AB (Stockholm, Sweden) (J.V.). We thank Karen Prince for assisting with graphics.
Compliance with Ethical Standards
Conflict of Interest
B.P.G. has a patent P1344SE00 pending to J.V. and B.P.G. as Inventors. Filed by BioGaia AB.
J.V. reports grants for unrestricted research support from BioGaia during the conduct of the study and shares as a member of the advisory board from Diversigen, outside the submitted work.
R.F. and S.A. declare that they have no conflict of interest.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
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