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. 2016 Nov;151(5):836–844. doi: 10.1053/j.gastro.2016.07.044

Figure 1.

Figure 1

Microbiota and diet control the activity of multiple cell types in the gut wall, including the ENS. For example, the bacterial metabolites SCFAs activate G-protein coupled receptors (eg, GPR41 and GPR43) on enteroendocrine cells of the intestinal epithelium resulting in enhanced production of GLP-1 and 5-HT and changes in gut motility. Gut microbiota also contribute to the conversion of primary bile acids into secondary bile acids, which activate TGR5 expressed by enteroendocrine cells and enteric neurons. TLR signalling (eg, TLR2 and TLR4) maintains subsets of enteric neurons and influences gut motility. In addition, microbiota is essential for the maintenance of mucosal glial cells, which express the neurotrophic factor GDNF and GFAP. 5-HT, Serotonin; α-MSH, α-melanocyte-stimulating hormone; GDNF, glial cell-derived neurotrophic factor; GFAP, glial fibrillary acidic protein; GLP-1, glucagon-like peptide-1; SERT, serotonin-selective reuptake transporter; Tph1, tryptophan hydroxylase 1.