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The GadX regulon affects virulence gene expression and adhesion of porcine enteropathogenic Escherichia coli in vitro

The ability of enteropathogenic Escherichia coli (EPEC) to express virulence factor genes and develop attaching and effacing (AE) lesions is inhibited in acidic environmental conditions. This inhibition is due to the activation of transcription factor GadX, which upregulates expression of glutamic a...

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Autores principales: Braun, Hannah-Sophie, Sponder, Gerhard, Aschenbach, Jörg R., Kerner, Katharina, Bauerfeind, Rolf, Deiner, Carolin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7386710/
https://www.ncbi.nlm.nih.gov/pubmed/32734036
http://dx.doi.org/10.1016/j.vas.2017.04.001
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author Braun, Hannah-Sophie
Sponder, Gerhard
Aschenbach, Jörg R.
Kerner, Katharina
Bauerfeind, Rolf
Deiner, Carolin
author_facet Braun, Hannah-Sophie
Sponder, Gerhard
Aschenbach, Jörg R.
Kerner, Katharina
Bauerfeind, Rolf
Deiner, Carolin
author_sort Braun, Hannah-Sophie
collection PubMed
description The ability of enteropathogenic Escherichia coli (EPEC) to express virulence factor genes and develop attaching and effacing (AE) lesions is inhibited in acidic environmental conditions. This inhibition is due to the activation of transcription factor GadX, which upregulates expression of glutamic acid decarboxylase (Gad). Gad, in turn, produces γ-aminobutyric acid (GABA), which was recently shown to have a beneficial effect on the jejunal epithelium in vitro due to increased mucin-1 levels. In the present study, we sought to test whether forced GadX activation/overexpression abolishes virulence associated features of EPEC and provokes increased GABA production. EPEC strains were isolated from diarrheic pigs and submitted to activation of GadX by acidification as well as gadX overexpression via an inducible expression vector plasmid. GABA concentrations in the growth medium, ability for adhesion to porcine intestinal epithelial cells (IPEC-J2) and virulence gene expression were determined. Growth in acidified media led to increased GABA levels, upregulated gadA/B expression and downregulated mRNA synthesis of the bacterial adhesin intimin. EPEC strains transformed with the gadX gene produced 2.1–3.4-fold higher GABA levels than empty-vector controls and completely lost their ability to adhere to IPEC-J2 cells and to induce actin accumulation. We conclude that intensified gadX activation can abolish the ability of EPEC to adhere to the intestinal epithelium by reducing the expression of major virulence genes.
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spelling pubmed-73867102020-07-29 The GadX regulon affects virulence gene expression and adhesion of porcine enteropathogenic Escherichia coli in vitro Braun, Hannah-Sophie Sponder, Gerhard Aschenbach, Jörg R. Kerner, Katharina Bauerfeind, Rolf Deiner, Carolin Vet Anim Sci Article The ability of enteropathogenic Escherichia coli (EPEC) to express virulence factor genes and develop attaching and effacing (AE) lesions is inhibited in acidic environmental conditions. This inhibition is due to the activation of transcription factor GadX, which upregulates expression of glutamic acid decarboxylase (Gad). Gad, in turn, produces γ-aminobutyric acid (GABA), which was recently shown to have a beneficial effect on the jejunal epithelium in vitro due to increased mucin-1 levels. In the present study, we sought to test whether forced GadX activation/overexpression abolishes virulence associated features of EPEC and provokes increased GABA production. EPEC strains were isolated from diarrheic pigs and submitted to activation of GadX by acidification as well as gadX overexpression via an inducible expression vector plasmid. GABA concentrations in the growth medium, ability for adhesion to porcine intestinal epithelial cells (IPEC-J2) and virulence gene expression were determined. Growth in acidified media led to increased GABA levels, upregulated gadA/B expression and downregulated mRNA synthesis of the bacterial adhesin intimin. EPEC strains transformed with the gadX gene produced 2.1–3.4-fold higher GABA levels than empty-vector controls and completely lost their ability to adhere to IPEC-J2 cells and to induce actin accumulation. We conclude that intensified gadX activation can abolish the ability of EPEC to adhere to the intestinal epithelium by reducing the expression of major virulence genes. Elsevier 2017-04-27 /pmc/articles/PMC7386710/ /pubmed/32734036 http://dx.doi.org/10.1016/j.vas.2017.04.001 Text en © 2017 The Authors http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Article
Braun, Hannah-Sophie
Sponder, Gerhard
Aschenbach, Jörg R.
Kerner, Katharina
Bauerfeind, Rolf
Deiner, Carolin
The GadX regulon affects virulence gene expression and adhesion of porcine enteropathogenic Escherichia coli in vitro
title The GadX regulon affects virulence gene expression and adhesion of porcine enteropathogenic Escherichia coli in vitro
title_full The GadX regulon affects virulence gene expression and adhesion of porcine enteropathogenic Escherichia coli in vitro
title_fullStr The GadX regulon affects virulence gene expression and adhesion of porcine enteropathogenic Escherichia coli in vitro
title_full_unstemmed The GadX regulon affects virulence gene expression and adhesion of porcine enteropathogenic Escherichia coli in vitro
title_short The GadX regulon affects virulence gene expression and adhesion of porcine enteropathogenic Escherichia coli in vitro
title_sort gadx regulon affects virulence gene expression and adhesion of porcine enteropathogenic escherichia coli in vitro
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7386710/
https://www.ncbi.nlm.nih.gov/pubmed/32734036
http://dx.doi.org/10.1016/j.vas.2017.04.001
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