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SliC is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during Neisseria gonorrhoeae infection

Lysozymes are nearly omnipresent as the first line of immune defense against microbes in animals. They exert bactericidal action through antimicrobial peptide activity and peptidoglycan hydrolysis. Gram-negative bacteria developed several weapons to battle lysozymes, including inhibitors of c-type l...

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Autores principales: Zielke, Ryszard A., Le Van, Adriana, Baarda, Benjamin I., Herrera, Marco F., Acosta, Christopher J., Jerse, Ann E., Sikora, Aleksandra E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033465/
https://www.ncbi.nlm.nih.gov/pubmed/29975784
http://dx.doi.org/10.1371/journal.ppat.1007081
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author Zielke, Ryszard A.
Le Van, Adriana
Baarda, Benjamin I.
Herrera, Marco F.
Acosta, Christopher J.
Jerse, Ann E.
Sikora, Aleksandra E.
author_facet Zielke, Ryszard A.
Le Van, Adriana
Baarda, Benjamin I.
Herrera, Marco F.
Acosta, Christopher J.
Jerse, Ann E.
Sikora, Aleksandra E.
author_sort Zielke, Ryszard A.
collection PubMed
description Lysozymes are nearly omnipresent as the first line of immune defense against microbes in animals. They exert bactericidal action through antimicrobial peptide activity and peptidoglycan hydrolysis. Gram-negative bacteria developed several weapons to battle lysozymes, including inhibitors of c-type lysozymes in the MliC/PliC family and the Neisseria adhesin complex protein (ACP). Until the recent discovery of ACP, no proteinaceous lysozyme inhibitors were reported for the genus Neisseria, including the important human pathogen N. gonorrhoeae. Here, we describe a previously unrecognized gonococcal virulence mechanism involving a protein encoded by the open reading frame ngo1063 that acts to counteract c-type Iysozyme and provides a competitive advantage in the murine model of gonorrhea. We named this protein SliC as a surface-exposed lysozyme inhibitor of c-type lysozyme. SliC displays low overall primary sequence similarity to the MliC/PliC inhibitors, but we demonstrate that it has a parallel inhibitory mechanism. Our studies provide the first evidence that bacterial proteinaceous lysozyme inhibitors protect against host lysozyme during infection based on lack of attenuation of the ΔsliC mutant in lysozyme knock-out mice, and that the conserved residues involved in lysozyme inhibition, S83 and K103, are functionally indispensable during infection in wild type mice. Recombinant SliC completely abrogated the lytic activity of human and chicken c-type lysozymes, showing a preference towards human lysozyme with an IC(50) of 1.85 μM and calculated K(D) value of 9.2 ± 1.9 μM. In contrast, mutated SliC bearing S83A and K103A substitutions failed to protect fluorescein-labeled cell-wall from lysozyme-mediated hydrolysis. Further, we present data revealing that SliC is a surface-displayed lipoprotein released in membrane vesicles that is expressed throughout all phases of growth, in conditions relevant to different niches of the human host, and during experimental infection of the murine genital tract. SliC is also highly conserved and expressed by diverse gonococcal isolates as well as N. meningitidis, N. lactamica, and N. weaveri. This study is the first to highlight the importance of an anti-lysozyme strategy to escape the innate immune response during N. gonorrhoeae infection.
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spelling pubmed-60334652018-07-19 SliC is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during Neisseria gonorrhoeae infection Zielke, Ryszard A. Le Van, Adriana Baarda, Benjamin I. Herrera, Marco F. Acosta, Christopher J. Jerse, Ann E. Sikora, Aleksandra E. PLoS Pathog Research Article Lysozymes are nearly omnipresent as the first line of immune defense against microbes in animals. They exert bactericidal action through antimicrobial peptide activity and peptidoglycan hydrolysis. Gram-negative bacteria developed several weapons to battle lysozymes, including inhibitors of c-type lysozymes in the MliC/PliC family and the Neisseria adhesin complex protein (ACP). Until the recent discovery of ACP, no proteinaceous lysozyme inhibitors were reported for the genus Neisseria, including the important human pathogen N. gonorrhoeae. Here, we describe a previously unrecognized gonococcal virulence mechanism involving a protein encoded by the open reading frame ngo1063 that acts to counteract c-type Iysozyme and provides a competitive advantage in the murine model of gonorrhea. We named this protein SliC as a surface-exposed lysozyme inhibitor of c-type lysozyme. SliC displays low overall primary sequence similarity to the MliC/PliC inhibitors, but we demonstrate that it has a parallel inhibitory mechanism. Our studies provide the first evidence that bacterial proteinaceous lysozyme inhibitors protect against host lysozyme during infection based on lack of attenuation of the ΔsliC mutant in lysozyme knock-out mice, and that the conserved residues involved in lysozyme inhibition, S83 and K103, are functionally indispensable during infection in wild type mice. Recombinant SliC completely abrogated the lytic activity of human and chicken c-type lysozymes, showing a preference towards human lysozyme with an IC(50) of 1.85 μM and calculated K(D) value of 9.2 ± 1.9 μM. In contrast, mutated SliC bearing S83A and K103A substitutions failed to protect fluorescein-labeled cell-wall from lysozyme-mediated hydrolysis. Further, we present data revealing that SliC is a surface-displayed lipoprotein released in membrane vesicles that is expressed throughout all phases of growth, in conditions relevant to different niches of the human host, and during experimental infection of the murine genital tract. SliC is also highly conserved and expressed by diverse gonococcal isolates as well as N. meningitidis, N. lactamica, and N. weaveri. This study is the first to highlight the importance of an anti-lysozyme strategy to escape the innate immune response during N. gonorrhoeae infection. Public Library of Science 2018-07-05 /pmc/articles/PMC6033465/ /pubmed/29975784 http://dx.doi.org/10.1371/journal.ppat.1007081 Text en https://creativecommons.org/publicdomain/zero/1.0/ This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 (https://creativecommons.org/publicdomain/zero/1.0/) public domain dedication.
spellingShingle Research Article
Zielke, Ryszard A.
Le Van, Adriana
Baarda, Benjamin I.
Herrera, Marco F.
Acosta, Christopher J.
Jerse, Ann E.
Sikora, Aleksandra E.
SliC is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during Neisseria gonorrhoeae infection
title SliC is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during Neisseria gonorrhoeae infection
title_full SliC is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during Neisseria gonorrhoeae infection
title_fullStr SliC is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during Neisseria gonorrhoeae infection
title_full_unstemmed SliC is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during Neisseria gonorrhoeae infection
title_short SliC is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during Neisseria gonorrhoeae infection
title_sort slic is a surface-displayed lipoprotein that is required for the anti-lysozyme strategy during neisseria gonorrhoeae infection
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033465/
https://www.ncbi.nlm.nih.gov/pubmed/29975784
http://dx.doi.org/10.1371/journal.ppat.1007081
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