. Author manuscript; available in PMC: 2024 Dec 1.

Published in final edited form as: Dig Dis Sci. 2023 Sep 29;68(12):4306–4320. doi: 10.1007/s10620-023-08122-w

Table 3.

Effects of metabolites on immune, tight junction, and cellular elements of intestinal barrier [47]

Metabolite	Microbial sources of metabolites	Receptors	Effects of metabolites			Citations
Metabolite	Microbial sources of metabolites	Receptors	Immune	TJ / cellular	Microbial	Citations

Butyrate	Clostridium clusters	GPR41, GPR109A, GPR65 (?)	↑ TGF-β	↓ proliferation of crypt stem cells ↑ TJ proteins (occlu- din, ZO-1)		[123]
Acetate	Bacteroides spp. Prevotella spp.	GPR43				[124]
Propionate	Bacteroides spp., Veillonella spp., Dialister spp. Ruminococcus spp.	GPR41, GPR43				[125]
Bile acids	Bacteroides spp., Eubacterium spp., Lactobacillus spp. Clostridium spp.	FXR, TGR5, pregnane X receptor (PXR), vitamin D (VDR)	↓ by UDCA, LCA	Permeability ↑ by DCA, CDCA ↓ IL-8 production by DCA, LCA		[126]
Tryptophan metabolites: kynurenic acid, HT, indole derivatives	Bacteroides spp., Lactobacillus spp. Clostridium spp.	GPR35 (?), Aryl hydrocarbon receptor (AHR), PXR	Indoles ↑ IL-10 to ↑ goblet cell differentiation	Indoles regulate epithelial repair and differentiation and reduce disassembly of adherens junction	Indole derivatives promote expression of anti-micro-bials	[127]

Modified from Iyer N, Corr SC. Gut Microbial Metabolite-Mediated Regulation of the Intestinal Barrier in the Pathogenesis of Inflammatory Bowel Disease. Nutrients. 2021;13[12]

GPR G protein receptors, FXR Farnesoid X receptor, TGR Triterpene glycoside receptor, TGF-B Transforming growth factor beta, UDCA Ursodeoxycholic acid, LCA Lithocholic acid, IL interleukin, ZO Zonula occludens, DCA Deoxycholic acid, CDCA Chenodeoxycholic acid, HT hydroxytryptamine