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...
Main Authors: | , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Frontiers Media S.A.
2021-06-01
|
Series: | Frontiers in Immunology |
Subjects: | |
Online Access: | https://www.frontiersin.org/articles/10.3389/fimmu.2021.653208/full |
id |
doaj-2a1d379ab3d14b0fa2a54033ad782027 |
---|---|
record_format |
Article |
spelling |
doaj-2a1d379ab3d14b0fa2a54033ad7820272021-06-04T06:24:26ZengFrontiers Media S.A.Frontiers in Immunology1664-32242021-06-011210.3389/fimmu.2021.653208653208Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan MetabolismHeather M. Grifka-WalkBrittany R. JenkinsDouglas J. KominskyTryptophan (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.https://www.frontiersin.org/articles/10.3389/fimmu.2021.653208/fulltryptophankynurenineindolemicrobiome & dysbiosismucosal immmunityaryl hydrocarbon receptor |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Heather M. Grifka-Walk Brittany R. Jenkins Douglas J. Kominsky |
spellingShingle |
Heather M. Grifka-Walk Brittany R. Jenkins Douglas J. Kominsky Amino Acid Trp: The Far Out Impacts of Host and Commensal Tryptophan Metabolism Frontiers in Immunology tryptophan kynurenine indole microbiome & dysbiosis mucosal immmunity aryl hydrocarbon receptor |
author_facet |
Heather M. Grifka-Walk Brittany R. Jenkins Douglas J. Kominsky |
author_sort |
Heather M. Grifka-Walk |
title |
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_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_sort |
amino acid trp: the far out impacts of host and commensal tryptophan metabolism |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Immunology |
issn |
1664-3224 |
publishDate |
2021-06-01 |
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. |
topic |
tryptophan kynurenine indole microbiome & dysbiosis mucosal immmunity aryl hydrocarbon receptor |
url |
https://www.frontiersin.org/articles/10.3389/fimmu.2021.653208/full |
work_keys_str_mv |
AT heathermgrifkawalk aminoacidtrpthefaroutimpactsofhostandcommensaltryptophanmetabolism AT brittanyrjenkins aminoacidtrpthefaroutimpactsofhostandcommensaltryptophanmetabolism AT douglasjkominsky aminoacidtrpthefaroutimpactsofhostandcommensaltryptophanmetabolism |
_version_ |
1721398324771160064 |