<named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation

ABSTRACT Helicobacter pylori is one of several pathogens that persist within the host despite a robust immune response. H. pylori elicits a proinflammatory response from host epithelia, resulting in the recruitment of immune cells which manifests as gastritis. Relatively little is known about how H....

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Autores principales:	Jennifer A. Gaddy, Jana N. Radin, Thomas W. Cullen, Walter J. Chazin, Eric P. Skaar, M. Stephen Trent, Holly M. S. Algood
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2015
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/f29f65b7f02a47cab94293d90ce26048
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spelling	oai:doaj.org-article:f29f65b7f02a47cab94293d90ce260482021-11-15T15:41:24Z<named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation10.1128/mBio.01349-152150-7511https://doaj.org/article/f29f65b7f02a47cab94293d90ce260482015-12-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01349-15https://doaj.org/toc/2150-7511ABSTRACT Helicobacter pylori is one of several pathogens that persist within the host despite a robust immune response. H. pylori elicits a proinflammatory response from host epithelia, resulting in the recruitment of immune cells which manifests as gastritis. Relatively little is known about how H. pylori survives antimicrobials, including calprotectin (CP), which is present during the inflammatory response. The data presented here suggest that one way H. pylori survives the nutrient sequestration by CP is through alteration of its outer membrane. CP-treated H. pylori demonstrates increased bacterial fitness in response to further coculture with CP. Moreover, CP-treated H. pylori cultures form biofilms and demonstrate decreased cell surface hydrophobicity. In response to CP, the H. pylori Lpx lipid A biosynthetic enzymes are not fully functional. The lipid A molecules observed in H. pylori cultures treated with CP indicate that the LpxF, LpxL, and LpxR enzyme functions are perturbed. Transcriptional analysis of lpxF, lpxL, and lpxR indicates that metal restriction by CP does not control this pathway through transcriptional regulation. Analyses of H. pylori lpx mutants reveal that loss of LpxF and LpxL results in increased fitness, similar to what is observed in the presence of CP; moreover, these mutants have significantly increased biofilm formation and reduced cell surface hydrophobicity. Taken together, these results demonstrate a novel mechanism of H. pylori resistance to the antimicrobial activity of CP via lipid A modification strategies and resulting biofilm formation. IMPORTANCE Helicobacter pylori evades recognition of the host's immune system by modifying the lipid A component of lipopolysaccharide. These results demonstrate for the first time that the lipid A modification pathway is influenced by the host's nutritional immune response. H. pylori's exposure to the host Mn- and Zn-binding protein calprotectin perturbs the function of 3 enzymes involved in the lipid A modification pathway. Moreover, CP treatment of H. pylori, or mutants with an altered lipid A, exhibit increased bacterial fitness and increased biofilm formation. This suggests that H. pylori modifies its cell surface structure to survive under the stress imposed by the host immune response. These results provide new insights into the molecular mechanisms that influence the biofilm lifestyle and how endotoxin modification, which renders H. pylori resistant to cationic antimicrobial peptides, can be inactivated in response to sequestration of nutrient metals.Jennifer A. GaddyJana N. RadinThomas W. CullenWalter J. ChazinEric P. SkaarM. Stephen TrentHolly M. S. AlgoodAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 6, Iss 6 (2015)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Jennifer A. Gaddy Jana N. Radin Thomas W. Cullen Walter J. Chazin Eric P. Skaar M. Stephen Trent Holly M. S. Algood <named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation
description	ABSTRACT Helicobacter pylori is one of several pathogens that persist within the host despite a robust immune response. H. pylori elicits a proinflammatory response from host epithelia, resulting in the recruitment of immune cells which manifests as gastritis. Relatively little is known about how H. pylori survives antimicrobials, including calprotectin (CP), which is present during the inflammatory response. The data presented here suggest that one way H. pylori survives the nutrient sequestration by CP is through alteration of its outer membrane. CP-treated H. pylori demonstrates increased bacterial fitness in response to further coculture with CP. Moreover, CP-treated H. pylori cultures form biofilms and demonstrate decreased cell surface hydrophobicity. In response to CP, the H. pylori Lpx lipid A biosynthetic enzymes are not fully functional. The lipid A molecules observed in H. pylori cultures treated with CP indicate that the LpxF, LpxL, and LpxR enzyme functions are perturbed. Transcriptional analysis of lpxF, lpxL, and lpxR indicates that metal restriction by CP does not control this pathway through transcriptional regulation. Analyses of H. pylori lpx mutants reveal that loss of LpxF and LpxL results in increased fitness, similar to what is observed in the presence of CP; moreover, these mutants have significantly increased biofilm formation and reduced cell surface hydrophobicity. Taken together, these results demonstrate a novel mechanism of H. pylori resistance to the antimicrobial activity of CP via lipid A modification strategies and resulting biofilm formation. IMPORTANCE Helicobacter pylori evades recognition of the host's immune system by modifying the lipid A component of lipopolysaccharide. These results demonstrate for the first time that the lipid A modification pathway is influenced by the host's nutritional immune response. H. pylori's exposure to the host Mn- and Zn-binding protein calprotectin perturbs the function of 3 enzymes involved in the lipid A modification pathway. Moreover, CP treatment of H. pylori, or mutants with an altered lipid A, exhibit increased bacterial fitness and increased biofilm formation. This suggests that H. pylori modifies its cell surface structure to survive under the stress imposed by the host immune response. These results provide new insights into the molecular mechanisms that influence the biofilm lifestyle and how endotoxin modification, which renders H. pylori resistant to cationic antimicrobial peptides, can be inactivated in response to sequestration of nutrient metals.
format	article
author	Jennifer A. Gaddy Jana N. Radin Thomas W. Cullen Walter J. Chazin Eric P. Skaar M. Stephen Trent Holly M. S. Algood
author_facet	Jennifer A. Gaddy Jana N. Radin Thomas W. Cullen Walter J. Chazin Eric P. Skaar M. Stephen Trent Holly M. S. Algood
author_sort	Jennifer A. Gaddy
title	<named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation
title_short	<named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation
title_full	<named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation
title_fullStr	<named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation
title_full_unstemmed	<named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation
title_sort	<named-content content-type="genus-species">helicobacter pylori</named-content> resists the antimicrobial activity of calprotectin via lipid a modification and associated biofilm formation
publisher	American Society for Microbiology
publishDate	2015
url	https://doaj.org/article/f29f65b7f02a47cab94293d90ce26048
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<named-content content-type="genus-species">Helicobacter pylori</named-content> Resists the Antimicrobial Activity of Calprotectin via Lipid A Modification and Associated Biofilm Formation

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