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Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes
Listeria monocytogenes is a Gram-positive, food-borne pathogen that lives a biphasic lifestyle, cycling between the environment and as a facultative intracellular pathogen of mammals. Upon entry into host cells, L. monocytogenes upregulates expression of glutathione synthase (GshF) and its product,...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Public Library of Science
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8372916/ https://www.ncbi.nlm.nih.gov/pubmed/34407151 http://dx.doi.org/10.1371/journal.ppat.1009819 |
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author | Anaya-Sanchez, Andrea Feng, Ying Berude, John C. Portnoy, Daniel A. |
author_facet | Anaya-Sanchez, Andrea Feng, Ying Berude, John C. Portnoy, Daniel A. |
author_sort | Anaya-Sanchez, Andrea |
collection | PubMed |
description | Listeria monocytogenes is a Gram-positive, food-borne pathogen that lives a biphasic lifestyle, cycling between the environment and as a facultative intracellular pathogen of mammals. Upon entry into host cells, L. monocytogenes upregulates expression of glutathione synthase (GshF) and its product, glutathione (GSH), which is an allosteric activator of the master virulence regulator PrfA. Although gshF mutants are highly attenuated for virulence in mice and form very small plaques in host cell monolayers, these virulence defects can be fully rescued by mutations that lock PrfA in its active conformation, referred to as PrfA*. While PrfA activation can be recapitulated in vitro by the addition of reducing agents, the precise biological cue(s) experienced by L. monocytogenes that lead to PrfA activation are not known. Here we performed a genetic screen to identify additional small-plaque mutants that were rescued by PrfA* and identified gloA, which encodes glyoxalase A, a component of a GSH-dependent methylglyoxal (MG) detoxification system. MG is a toxic byproduct of metabolism produced by both the host and pathogen, which if accumulated, causes DNA damage and protein glycation. As a facultative intracellular pathogen, L. monocytogenes must protect itself from MG produced by its own metabolic processes and that of its host. We report that gloA mutants grow normally in broth, are sensitive to exogenous MG and severely attenuated upon IV infection in mice, but are fully rescued for virulence in a PrfA* background. We demonstrate that transcriptional activation of gshF increased upon MG challenge in vitro, and while this resulted in higher levels of GSH for wild-type L. monocytogenes, the glyoxalase mutants had decreased levels of GSH, presumably due to the accumulation of the GSH-MG hemithioacetal adduct. These data suggest that MG acts as a host cue that leads to GSH production and activation of PrfA. |
format | Online Article Text |
id | pubmed-8372916 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-83729162021-08-19 Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes Anaya-Sanchez, Andrea Feng, Ying Berude, John C. Portnoy, Daniel A. PLoS Pathog Research Article Listeria monocytogenes is a Gram-positive, food-borne pathogen that lives a biphasic lifestyle, cycling between the environment and as a facultative intracellular pathogen of mammals. Upon entry into host cells, L. monocytogenes upregulates expression of glutathione synthase (GshF) and its product, glutathione (GSH), which is an allosteric activator of the master virulence regulator PrfA. Although gshF mutants are highly attenuated for virulence in mice and form very small plaques in host cell monolayers, these virulence defects can be fully rescued by mutations that lock PrfA in its active conformation, referred to as PrfA*. While PrfA activation can be recapitulated in vitro by the addition of reducing agents, the precise biological cue(s) experienced by L. monocytogenes that lead to PrfA activation are not known. Here we performed a genetic screen to identify additional small-plaque mutants that were rescued by PrfA* and identified gloA, which encodes glyoxalase A, a component of a GSH-dependent methylglyoxal (MG) detoxification system. MG is a toxic byproduct of metabolism produced by both the host and pathogen, which if accumulated, causes DNA damage and protein glycation. As a facultative intracellular pathogen, L. monocytogenes must protect itself from MG produced by its own metabolic processes and that of its host. We report that gloA mutants grow normally in broth, are sensitive to exogenous MG and severely attenuated upon IV infection in mice, but are fully rescued for virulence in a PrfA* background. We demonstrate that transcriptional activation of gshF increased upon MG challenge in vitro, and while this resulted in higher levels of GSH for wild-type L. monocytogenes, the glyoxalase mutants had decreased levels of GSH, presumably due to the accumulation of the GSH-MG hemithioacetal adduct. These data suggest that MG acts as a host cue that leads to GSH production and activation of PrfA. Public Library of Science 2021-08-18 /pmc/articles/PMC8372916/ /pubmed/34407151 http://dx.doi.org/10.1371/journal.ppat.1009819 Text en © 2021 Anaya-Sanchez et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Anaya-Sanchez, Andrea Feng, Ying Berude, John C. Portnoy, Daniel A. Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes |
title | Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes |
title_full | Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes |
title_fullStr | Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes |
title_full_unstemmed | Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes |
title_short | Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes |
title_sort | detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in listeria monocytogenes |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8372916/ https://www.ncbi.nlm.nih.gov/pubmed/34407151 http://dx.doi.org/10.1371/journal.ppat.1009819 |
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