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Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism
Tryptophan (Trp) is an essential amino acid primarily derived from the diet for use by the host for protein synthesis. The intestinal tract is lined with cells, both host and microbial, that uptake and metabolize Trp to also generate important signaling molecules. Serotonin (5-HT), kynurenine and it...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2021
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8213022/ https://www.ncbi.nlm.nih.gov/pubmed/34149693 http://dx.doi.org/10.3389/fimmu.2021.653208 |
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author | Grifka-Walk, Heather M. Jenkins, Brittany R. Kominsky, Douglas J. |
author_facet | Grifka-Walk, Heather M. Jenkins, Brittany R. Kominsky, Douglas J. |
author_sort | Grifka-Walk, Heather M. |
collection | PubMed |
description | Tryptophan (Trp) is an essential amino acid primarily derived from the diet for use by the host for protein synthesis. The intestinal tract is lined with cells, both host and microbial, that uptake and metabolize Trp to also generate important signaling molecules. Serotonin (5-HT), kynurenine and its downstream metabolites, and to a lesser extent other neurotransmitters are generated by the host to signal onto host receptors and elicit physiological effects. 5-HT production by neurons in the CNS regulates sleep, mood, and appetite; 5-HT production in the intestinal tract by enterochromaffin cells regulates gastric motility and inflammation in the periphery. Kynurenine can signal onto the aryl hydrocarbon receptor (AHR) to elicit pleiotropic responses from several cell types including epithelial and immune cells, or can be further metabolized into bioactive molecules to influence neurodegenerative disease. There is a remarkable amount of cross-talk with the microbiome with regard to tryptophan metabolites as well. The gut microbiome can regulate the production of host tryptophan metabolites and can use dietary or recycled trp to generate bioactive metabolites themselves. Trp derivatives like indole are able to signal onto xenobiotic receptors, including AHR, to elicit tolerogenic effects. Here, we review studies that demonstrate that tryptophan represents a key intra-kingdom signaling molecule. |
format | Online Article Text |
id | pubmed-8213022 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-82130222021-06-19 Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism Grifka-Walk, Heather M. Jenkins, Brittany R. Kominsky, Douglas J. Front Immunol Immunology Tryptophan (Trp) is an essential amino acid primarily derived from the diet for use by the host for protein synthesis. The intestinal tract is lined with cells, both host and microbial, that uptake and metabolize Trp to also generate important signaling molecules. Serotonin (5-HT), kynurenine and its downstream metabolites, and to a lesser extent other neurotransmitters are generated by the host to signal onto host receptors and elicit physiological effects. 5-HT production by neurons in the CNS regulates sleep, mood, and appetite; 5-HT production in the intestinal tract by enterochromaffin cells regulates gastric motility and inflammation in the periphery. Kynurenine can signal onto the aryl hydrocarbon receptor (AHR) to elicit pleiotropic responses from several cell types including epithelial and immune cells, or can be further metabolized into bioactive molecules to influence neurodegenerative disease. There is a remarkable amount of cross-talk with the microbiome with regard to tryptophan metabolites as well. The gut microbiome can regulate the production of host tryptophan metabolites and can use dietary or recycled trp to generate bioactive metabolites themselves. Trp derivatives like indole are able to signal onto xenobiotic receptors, including AHR, to elicit tolerogenic effects. Here, we review studies that demonstrate that tryptophan represents a key intra-kingdom signaling molecule. Frontiers Media S.A. 2021-06-04 /pmc/articles/PMC8213022/ /pubmed/34149693 http://dx.doi.org/10.3389/fimmu.2021.653208 Text en Copyright © 2021 Grifka-Walk, Jenkins and Kominsky https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Immunology Grifka-Walk, Heather M. Jenkins, Brittany R. Kominsky, Douglas J. Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism |
title | Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism |
title_full | Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism |
title_fullStr | Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism |
title_full_unstemmed | Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism |
title_short | Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism |
title_sort | amino acid trp: the far out impacts of host and commensal tryptophan metabolism |
topic | Immunology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8213022/ https://www.ncbi.nlm.nih.gov/pubmed/34149693 http://dx.doi.org/10.3389/fimmu.2021.653208 |
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