1
|
Caliot E, Firon A, Solgadi A, Trieu-Cuot P, Dramsi S. Lipid lysination by MprF contributes to hemolytic pigment retention in group B Streptococcus. Res Microbiol 2024; 175:104231. [PMID: 39197696 DOI: 10.1016/j.resmic.2024.104231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 07/17/2024] [Accepted: 08/20/2024] [Indexed: 09/01/2024]
Abstract
Group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis. A major virulence factor is a pigmented beta-haemolytic/cyto-lysin (β-h/c) toxin with an ornithine rhamnolipid structure. We initially observed that absence of MprF enzyme altered pigmentation and haemolytic activity in GBS. Next, we showed that MprF-dependent lipid lysination contributes to the retention of the ornithine rhamnolipid within GBS membrane. Furthermore, cationic lipidation by MprF altered membrane properties contributing to resistance to the cyclic lipopeptide daptomycin and to acidic pH. This study highlights the importance of cationic lipids in cell envelope homeostasis and in modulating β-h/c activity.
Collapse
Affiliation(s)
- Elise Caliot
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Biology of Gram-positive Pathogens Unit, F-75015 Paris, France
| | - Arnaud Firon
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Biology of Gram-positive Pathogens Unit, F-75015 Paris, France
| | - Audrey Solgadi
- UMS-IPSIT SAMM Facility, Université Paris-Saclay, Inserm, CNRS, Ingénierie et Plateformes au Service de l'Innovation Thérapeutique, F-91400 Orsay, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Biology of Gram-positive Pathogens Unit, F-75015 Paris, France.
| | - Shaynoor Dramsi
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Biology of Gram-positive Pathogens Unit, F-75015 Paris, France.
| |
Collapse
|
2
|
Goh KGK, Desai D, Thapa R, Prince D, Acharya D, Sullivan MJ, Ulett GC. An opportunistic pathogen under stress: how Group B Streptococcus responds to cytotoxic reactive species and conditions of metal ion imbalance to survive. FEMS Microbiol Rev 2024; 48:fuae009. [PMID: 38678005 PMCID: PMC11098048 DOI: 10.1093/femsre/fuae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 03/26/2024] [Accepted: 04/16/2024] [Indexed: 04/29/2024] Open
Abstract
Group B Streptococcus (GBS; also known as Streptococcus agalactiae) is an opportunistic bacterial pathogen that causes sepsis, meningitis, pneumonia, and skin and soft tissue infections in neonates and healthy or immunocompromised adults. GBS is well-adapted to survive in humans due to a plethora of virulence mechanisms that afford responses to support bacterial survival in dynamic host environments. These mechanisms and responses include counteraction of cell death from exposure to excess metal ions that can cause mismetallation and cytotoxicity, and strategies to combat molecules such as reactive oxygen and nitrogen species that are generated as part of innate host defence. Cytotoxicity from reactive molecules can stem from damage to proteins, DNA, and membrane lipids, potentially leading to bacterial cell death inside phagocytic cells or within extracellular spaces within the host. Deciphering the ways in which GBS responds to the stress of cytotoxic reactive molecules within the host will benefit the development of novel therapeutic and preventative strategies to manage the burden of GBS disease. This review summarizes knowledge of GBS carriage in humans and the mechanisms used by the bacteria to circumvent killing by these important elements of host immune defence: oxidative stress, nitrosative stress, and stress from metal ion intoxication/mismetallation.
Collapse
Affiliation(s)
- Kelvin G K Goh
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Devika Desai
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Ruby Thapa
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Darren Prince
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Dhruba Acharya
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Matthew J Sullivan
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom
| | - Glen C Ulett
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| |
Collapse
|
3
|
De Gaetano GV, Lentini G, Coppolino F, Famà A, Pietrocola G, Beninati C. Engagement of α 3β 1 and α 2β 1 integrins by hypervirulent Streptococcus agalactiae in invasion of polarized enterocytes. Front Microbiol 2024; 15:1367898. [PMID: 38511003 PMCID: PMC10951081 DOI: 10.3389/fmicb.2024.1367898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 02/19/2024] [Indexed: 03/22/2024] Open
Abstract
The gut represents an important site of colonization of the commensal bacterium Streptococcus agalactiae (group B Streptococcus or GBS), which can also behave as a deadly pathogen in neonates and adults. Invasion of the intestinal epithelial barrier is likely a crucial step in the pathogenesis of neonatal infections caused by GBS belonging to clonal complex 17 (CC17). We have previously shown that the prototypical CC17 BM110 strain invades polarized enterocyte-like cells through their lateral surfaces using an endocytic pathway. By analyzing the cellular distribution of putative GBS receptors in human enterocyte-like Caco-2 cells, we find here that the alpha 3 (α3) and alpha 2 (α2) integrin subunits are selectively expressed on lateral enterocyte surfaces at equatorial and parabasal levels along the vertical axis of polarized cells, in an area corresponding to GBS entry sites. The α3β1 and α2β1 integrins were not readily accessible in fully differentiated Caco-2 monolayers but could be exposed to specific antibodies after weakening of intercellular junctions in calcium-free media. Under these conditions, anti-α3β1 and anti-α2β1 antibodies significantly reduced GBS adhesion to and invasion of enterocytes. After endocytosis, α3β1 and α2β1 integrins localized to areas of actin remodeling around GBS containing vacuoles. Taken together, these data indicate that GBS can invade enterocytes by binding to α3β1 and α2β1 integrins on the lateral membrane of polarized enterocytes, resulting in cytoskeletal remodeling and bacterial internalization. Blocking integrins might represent a viable strategy to prevent GBS invasion of gut epithelial tissues.
Collapse
Affiliation(s)
| | - Germana Lentini
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Francesco Coppolino
- Department of Biomedical, Dental and Imaging Sciences, University of Messina, Messina, Italy
| | - Agata Famà
- Department of Human Pathology, University of Messina, Messina, Italy
| | - Giampiero Pietrocola
- Department of Molecular Medicine, Biochemistry Section, University of Pavia, Pavia, Italy
| | - Concetta Beninati
- Department of Human Pathology, University of Messina, Messina, Italy
- Scylla Biotech Srl, Messina, Italy
| |
Collapse
|
4
|
Furuta A, Coleman M, Casares R, Seepersaud R, Orvis A, Brokaw A, Quach P, Nguyen S, Sweeney E, Sharma K, Wallen G, Sanghavi R, Mateos-Gil J, Cuerva JM, Millán A, Rajagopal L. CD1 and iNKT cells mediate immune responses against the GBS hemolytic lipid toxin induced by a non-toxic analog. PLoS Pathog 2023; 19:e1011490. [PMID: 37384812 DOI: 10.1371/journal.ppat.1011490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 06/14/2023] [Indexed: 07/01/2023] Open
Abstract
Although hemolytic lipids have been discovered from many human pathogens including Group B Streptococcus (GBS), strategies that neutralize their function are lacking. GBS is a leading cause of pregnancy-associated neonatal infections, and adult GBS infections are on the rise. The GBS hemolytic lipid toxin or granadaene, is cytotoxic to many immune cells including T and B cells. We previously showed that mice immunized with a synthetic nontoxic analog of granadaene known as R-P4 had reduced bacterial dissemination during systemic infection. However, mechanisms important for R-P4 mediated immune protection was not understood. Here, we show that immune serum from R-P4-immunized mice facilitate GBS opsonophagocytic killing and protect naïve mice from GBS infection. Further, CD4+ T cells isolated from R-P4-immunized mice proliferated in response to R-P4 stimulation in a CD1d- and iNKT cell-dependent manner. Consistent with these observations, R-P4 immunized mice lacking CD1d or CD1d-restricted iNKT cells exhibit elevated bacterial burden. Additionally, adoptive transfer of iNKT cells from R-P4 vaccinated mice significantly reduced GBS dissemination compared to adjuvant controls. Finally, maternal R-P4 vaccination provided protection against ascending GBS infection during pregnancy. These findings are relevant in the development of therapeutic strategies targeting lipid cytotoxins.
Collapse
Affiliation(s)
- Anna Furuta
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Michelle Coleman
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Raquel Casares
- Department of Organic Chemistry, University of Granada, Granada, Spain
| | - Ravin Seepersaud
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Austyn Orvis
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Alyssa Brokaw
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Phoenicia Quach
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Shayla Nguyen
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Erin Sweeney
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Kavita Sharma
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Grace Wallen
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Rhea Sanghavi
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Jaime Mateos-Gil
- Department of Organic Chemistry, University of Granada, Granada, Spain
| | | | - Alba Millán
- Department of Organic Chemistry, University of Granada, Granada, Spain
| | - Lakshmi Rajagopal
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
| |
Collapse
|
5
|
A Novel Conserved Protein in Streptococcus agalactiae, BvaP, Is Important for Vaginal Colonization and Biofilm Formation. mSphere 2022; 7:e0042122. [PMID: 36218343 PMCID: PMC9769775 DOI: 10.1128/msphere.00421-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Streptococcus agalactiae (group B streptococcus [GBS]) infections in neonates are often fatal and strongly associated with maternal GBS vaginal colonization. Here, we investigated the role of an uncharacterized protein, BvaP, in GBS vaginal colonization. bvaP was previously identified as the most highly upregulated gene in the GBS A909 transcriptome when comparing vaginal colonization to growth in liquid culture. We found that the absence of BvaP affects the ability of GBS to adhere to extracellular matrix components and human vaginal epithelial cells, and the ability of a ΔbvaP mutant to colonize the murine vaginal tract was significantly decreased. Cellular morphological alterations such as changes in cell shape, chain length, and clumping were also observed in a knockout mutant strain. Given its high expression level in vivo, high degree of conservation among GBS strains, and role in vaginal colonization, BvaP may be an eligible target for GBS vaccination and/or drug therapy. IMPORTANCE Neonatal GBS disease is a major cause of morbidity and mortality, and maternal vaginal colonization is the leading risk factor for the disease. Colonization prevention would greatly impact the rates of disease transmission, but vaccine development has stalled as capsular polysaccharide vaccines have low immunogenicity in vivo. While these vaccines are still in development, the addition of a protein conjugate may prove fruitful in increasing immunogenicity and strain coverage across GBS serotypes. Previous research identified sak_1753 as a highly upregulated gene during murine vaginal colonization. This study reveals that Sak_1753 is required to maintain proper GBS cellular morphology and colonization phenotypes and is required for full in vivo vaginal colonization in a murine model. We have renamed Sak_1753 group B streptococcus vaginal adherence protein (BvaP). The findings of this study indicate that BvaP is important for GBS colonization of the vaginal tract and, given its high expression level in vivo and strain conservation, may be a candidate for vaccine development.
Collapse
|
6
|
Deshayes de Cambronne R, Fouet A, Picart A, Bourrel AS, Anjou C, Bouvier G, Candeias C, Bouaboud A, Costa L, Boulay AC, Cohen-Salmon M, Plu I, Rambaud C, Faurobert E, Albigès-Rizo C, Tazi A, Poyart C, Guignot J. CC17 group B Streptococcus exploits integrins for neonatal meningitis development. J Clin Invest 2021; 131:136737. [PMID: 33465054 DOI: 10.1172/jci136737] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 01/13/2021] [Indexed: 12/28/2022] Open
Abstract
Group B Streptococcus (GBS) is the major cause of human neonatal infections. A single clone, designated CC17-GBS, accounts for more than 80% of meningitis cases, the most severe form of the infection. However, the events allowing blood-borne GBS to penetrate the brain remain largely elusive. In this study, we identified the host transmembrane receptors α5β1 and αvβ3 integrins as the ligands of Srr2, a major CC17-GBS-specific adhesin. Two motifs located in the binding region of Srr2 were responsible for the interaction between CC17-GBS and these integrins. We demonstrated in a blood-brain-barrier cellular model that both integrins contributed to the adhesion and internalization of CC17-GBS. Strikingly, both integrins were overexpressed during the postnatal period in the brain vessels of the blood-brain barrier and blood-cerebrospinal fluid barrier and contributed to juvenile susceptibility to CC17 meningitis. Finally, blocking these integrins decreased the ability of CC17-GBS to cross into the CNS of juvenile mice in an in vivo model of meningitis. Our study demonstrated that CC17-GBS exploits integrins in order to cross the brain vessels, leading to meningitis. Importantly, it provides host molecular insights into neonate's susceptibility to CC17-GBS meningitis, thereby opening new perspectives for therapeutic and prevention strategies of GBS-elicited meningitis.
Collapse
Affiliation(s)
| | - Agnès Fouet
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Amandine Picart
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Anne-Sophie Bourrel
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France.,Hôpitaux Universitaires Paris Centre, Cochin, Assistance Publique Hôpitaux de Paris, France
| | - Cyril Anjou
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Guillaume Bouvier
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR3528, C3BI, Paris, France
| | - Cristina Candeias
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Abdelouhab Bouaboud
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Lionel Costa
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Anne-Cécile Boulay
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR7241, INSERM U1050, PSL Research University, Paris, France
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR7241, INSERM U1050, PSL Research University, Paris, France
| | - Isabelle Plu
- Sorbonne Université/Département de Neuropathologie Raymond Escourolle - Hôpital Pitié-Salpêtrière - Assistance Publique-Hôpitaux de Paris, France
| | - Caroline Rambaud
- Université de Versailles Saint Quentin en Yvelines (Université Paris-Saclay)/Service d'anatomie-pathologique et médecine légale, Hôpital Raymond Poincaré, Garches, France
| | - Eva Faurobert
- INSERM U1209, CNRS UMR 5309, Institute for Advanced Biosciences, France/Université Grenoble Alpes, La Tronche, France
| | - Corinne Albigès-Rizo
- INSERM U1209, CNRS UMR 5309, Institute for Advanced Biosciences, France/Université Grenoble Alpes, La Tronche, France
| | - Asmaa Tazi
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France.,Hôpitaux Universitaires Paris Centre, Cochin, Assistance Publique Hôpitaux de Paris, France.,Centre National de Référence des Streptocoques, France
| | - Claire Poyart
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France.,Hôpitaux Universitaires Paris Centre, Cochin, Assistance Publique Hôpitaux de Paris, France.,Centre National de Référence des Streptocoques, France
| | - Julie Guignot
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, Paris, France
| |
Collapse
|
7
|
Mazzuoli MV, Daunesse M, Varet H, Rosinski-Chupin I, Legendre R, Sismeiro O, Gominet M, Kaminski PA, Glaser P, Chica C, Trieu-Cuot P, Firon A. The CovR regulatory network drives the evolution of Group B Streptococcus virulence. PLoS Genet 2021; 17:e1009761. [PMID: 34491998 PMCID: PMC8448333 DOI: 10.1371/journal.pgen.1009761] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 09/17/2021] [Accepted: 08/09/2021] [Indexed: 01/31/2023] Open
Abstract
Virulence of the neonatal pathogen Group B Streptococcus is under the control of the master regulator CovR. Inactivation of CovR is associated with large-scale transcriptome remodeling and impairs almost every step of the interaction between the pathogen and the host. However, transcriptome analyses suggested a plasticity of the CovR signaling pathway in clinical isolates leading to phenotypic heterogeneity in the bacterial population. In this study, we characterized the CovR regulatory network in a strain representative of the CC-17 hypervirulent lineage responsible of the majority of neonatal meningitis. Transcriptome and genome-wide binding analysis reveal the architecture of the CovR network characterized by the direct repression of a large array of virulence-associated genes and the extent of co-regulation at specific loci. Comparative functional analysis of the signaling network links strain-specificities to the regulation of the pan-genome, including the two specific hypervirulent adhesins and horizontally acquired genes, to mutations in CovR-regulated promoters, and to variability in CovR activation by phosphorylation. This regulatory adaptation occurs at the level of genes, promoters, and of CovR itself, and allows to globally reshape the expression of virulence genes. Overall, our results reveal the direct, coordinated, and strain-specific regulation of virulence genes by the master regulator CovR and suggest that the intra-species evolution of the signaling network is as important as the expression of specific virulence factors in the emergence of clone associated with specific diseases. Streptococcus agalactiae, commonly known as the Group B Streptococcus (GBS), is a commensal bacterium of the intestinal and vaginal tracts found in approximately 30% of healthy adults. However, GBS is also an opportunistic pathogen and the leading cause of neonatal invasive infections. Epidemiologic data have identified a particular GBS clone, designated the CC-17 hypervirulent clonal complex, as responsible for the overwhelming majority of neonatal meningitis. The hypervirulence of CC-17 has been linked to the expression of two specific surface proteins increasing their abilities to cross epithelial and endothelial barriers. In this study, we characterized the role of the major regulator of virulence gene expression, the CovR response regulator, in a representative hypervirulent strain. Transcriptome and genome-wide binding analysis reveal the architecture of the CovR signaling network characterized by the direct repression of a large array of virulence-associated genes, including the specific hypervirulent adhesins. Comparative analysis in a non-CC-17 wild type strain demonstrates a high level of plasticity of the regulatory network, allowing to globally reshape pathogen-host interaction. Overall, our results suggest that the intra-species evolution of the regulatory network is an important factor in the emergence of GBS clones associated with specific pathologies.
Collapse
Affiliation(s)
- Maria-Vittoria Mazzuoli
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR2001 Microbiologie Intégrative et Moléculaire, Institut Pasteur, Paris, France
- Sorbonne Paris Cité, Université de Paris, Paris, France
| | - Maëlle Daunesse
- Hub de Bioinformatique et Biostatistique—Département Biologie Computationnelle, Institut Pasteur, Paris, France
| | - Hugo Varet
- Hub de Bioinformatique et Biostatistique—Département Biologie Computationnelle, Institut Pasteur, Paris, France
- Plate-forme Technologique Biomics—Centre de Ressources et Recherches Technologiques (C2RT), Institut Pasteur, Paris, France
| | - Isabelle Rosinski-Chupin
- Unité Écologie et Évolution de la Résistance aux Antibiotiques, CNRS UMR3525, Institut Pasteur, Paris, France
| | - Rachel Legendre
- Hub de Bioinformatique et Biostatistique—Département Biologie Computationnelle, Institut Pasteur, Paris, France
- Plate-forme Technologique Biomics—Centre de Ressources et Recherches Technologiques (C2RT), Institut Pasteur, Paris, France
| | - Odile Sismeiro
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR2001 Microbiologie Intégrative et Moléculaire, Institut Pasteur, Paris, France
- Plate-forme Technologique Biomics—Centre de Ressources et Recherches Technologiques (C2RT), Institut Pasteur, Paris, France
| | - Myriam Gominet
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR2001 Microbiologie Intégrative et Moléculaire, Institut Pasteur, Paris, France
| | - Pierre Alexandre Kaminski
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR2001 Microbiologie Intégrative et Moléculaire, Institut Pasteur, Paris, France
| | - Philippe Glaser
- Unité Écologie et Évolution de la Résistance aux Antibiotiques, CNRS UMR3525, Institut Pasteur, Paris, France
| | - Claudia Chica
- Hub de Bioinformatique et Biostatistique—Département Biologie Computationnelle, Institut Pasteur, Paris, France
| | - Patrick Trieu-Cuot
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR2001 Microbiologie Intégrative et Moléculaire, Institut Pasteur, Paris, France
| | - Arnaud Firon
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR2001 Microbiologie Intégrative et Moléculaire, Institut Pasteur, Paris, France
- * E-mail:
| |
Collapse
|
8
|
Arora S, Gordon J, Hook M. Collagen Binding Proteins of Gram-Positive Pathogens. Front Microbiol 2021; 12:628798. [PMID: 33613497 PMCID: PMC7893114 DOI: 10.3389/fmicb.2021.628798] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/11/2021] [Indexed: 12/12/2022] Open
Abstract
Collagens are the primary structural components of mammalian extracellular matrices. In addition, collagens regulate tissue development, regeneration and host defense through interaction with specific cellular receptors. Their unique triple helix structure, which requires a glycine residue every third amino acid, is the defining structural feature of collagens. There are 28 genetically distinct collagens in humans. In addition, several other unrelated human proteins contain a collagen domain. Gram-positive bacteria of the genera Staphylococcus, Streptococcus, Enterococcus, and Bacillus express cell surface proteins that bind to collagen. These proteins of Gram-positive pathogens are modular proteins that can be classified into different structural families. This review will focus on the different structural families of collagen binding proteins of Gram-positive pathogen. We will describe how these proteins interact with the triple helix in collagens and other host proteins containing a collagenous domain and discuss how these interactions can contribute to the pathogenic processes.
Collapse
Affiliation(s)
- Srishtee Arora
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
| | - Jay Gordon
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
| | - Magnus Hook
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
| |
Collapse
|
9
|
Genetic Basis Underlying the Hyperhemolytic Phenotype of Streptococcus agalactiae Strain CNCTC10/84. J Bacteriol 2020; 202:JB.00504-20. [PMID: 32958630 DOI: 10.1128/jb.00504-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 09/11/2020] [Indexed: 01/30/2023] Open
Abstract
Streptococcus agalactiae (group B streptococcus [GBS]) is a major cause of infections in newborns, pregnant women, and immunocompromised patients. GBS strain CNCTC10/84 is a clinical isolate that has high virulence in animal models of infection and has been used extensively to study GBS pathogenesis. Two unusual features of this strain are hyperhemolytic activity and hypo-CAMP factor activity. These two phenotypes are typical of GBS strains that are functionally deficient in the CovR-CovS two-component regulatory system. A previous whole-genome sequencing study found that strain CNCTC10/84 has intact covR and covS regulatory genes. We investigated CovR-CovS regulation in CNCTC10/84 and discovered that a single-nucleotide insertion in a homopolymeric tract in the covR promoter region underlies the strong hemolytic activity and weak CAMP activity of this strain. Using isogenic mutant strains, we demonstrate that this single-nucleotide insertion confers significantly decreased expression of covR and covS and altered expression of CovR-CovS-regulated genes, including that of genes encoding β-hemolysin and CAMP factor. This single-nucleotide insertion also confers significantly increased GBS survival in human whole blood ex vivo IMPORTANCE Group B streptococcus (GBS) is the leading cause of neonatal sepsis, pneumonia, and meningitis. GBS strain CNCTC10/84 is a highly virulent blood isolate that has been used extensively to study GBS pathogenesis for over 20 years. Strain CNCTC10/84 has an unusually strong hemolytic activity, but the genetic basis is unknown. In this study, we discovered that a single-nucleotide insertion in an intergenic homopolymeric tract is responsible for the elevated hemolytic activity of CNCTC10/84.
Collapse
|
10
|
Vornhagen J, Adams Waldorf KM, Rajagopal L. Perinatal Group B Streptococcal Infections: Virulence Factors, Immunity, and Prevention Strategies. Trends Microbiol 2017. [PMID: 28633864 DOI: 10.1016/j.tim.2017.05.013] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Group B streptococcus (GBS) or Streptococcus agalactiae is a β-hemolytic, Gram-positive bacterium that is a leading cause of neonatal infections. GBS commonly colonizes the lower gastrointestinal and genital tracts and, during pregnancy, neonates are at risk of infection. Although intrapartum antibiotic prophylaxis during labor and delivery has decreased the incidence of early-onset neonatal infection, these measures do not prevent ascending infection that can occur earlier in pregnancy leading to preterm births, stillbirths, or late-onset neonatal infections. Prevention of GBS infection in pregnancy is complex and is likely influenced by multiple factors, including pathogenicity, host factors, vaginal microbiome, false-negative screening, and/or changes in antibiotic resistance. A deeper understanding of the mechanisms of GBS infections during pregnancy will facilitate the development of novel therapeutics and vaccines. Here, we summarize and discuss important advancements in our understanding of GBS vaginal colonization, ascending infection, and preterm birth.
Collapse
Affiliation(s)
- Jay Vornhagen
- Department of Global Health, University of Washington, Seattle, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Kristina M Adams Waldorf
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, USA; Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden
| | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA.
| |
Collapse
|
11
|
Avilés-Reyes A, Miller JH, Lemos JA, Abranches J. Collagen-binding proteins of Streptococcus mutans and related streptococci. Mol Oral Microbiol 2016; 32:89-106. [PMID: 26991416 DOI: 10.1111/omi.12158] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2016] [Indexed: 12/13/2022]
Abstract
The ability of Streptococcus mutans to interact with collagen through the expression of collagen-binding proteins (CBPs) bestows this oral pathogen with an alternative to the sucrose-dependent mechanism of colonization classically attributed to caries development. Based on the abundance and distribution of collagen throughout the human body, stringent adherence to this molecule grants S. mutans with the opportunity to establish infection at different host sites. Surface proteins, such as SpaP, WapA, Cnm and Cbm, have been shown to bind collagen in vitro, and it has been suggested that these molecules play a role in colonization of oral and extra-oral tissues. However, robust collagen binding is not achieved by all strains of S. mutans, particularly those that lack Cnm or Cbm. These observations merit careful dissection of the contribution from these different CBPs towards tissue colonization and virulence. In this review, we will discuss the current understanding of mechanisms used by S. mutans and related streptococci to colonize collagenous tissues, and the possible contribution of CBPs to infections in different sites of the host.
Collapse
Affiliation(s)
- A Avilés-Reyes
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - J H Miller
- Department of Anesthesiology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - J A Lemos
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - J Abranches
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| |
Collapse
|
12
|
Chuzeville S, Dramsi S, Madec JY, Haenni M, Payot S. Antigen I/II encoded by integrative and conjugative elements of Streptococcus agalactiae and role in biofilm formation. Microb Pathog 2015; 88:1-9. [PMID: 26232503 DOI: 10.1016/j.micpath.2015.07.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 07/13/2015] [Accepted: 07/20/2015] [Indexed: 10/23/2022]
Abstract
Streptococcus agalactiae (i.e. Group B streptococcus, GBS) is a major human and animal pathogen. Genes encoding putative surface proteins and in particular an antigen I/II have been identified on Integrative and Conjugative Elements (ICEs) found in GBS. Antigens I/II are multimodal adhesins promoting colonization of the oral cavity by streptococci such as Streptococcus gordonii and Streptococcus mutans. The prevalence and diversity of antigens I/II in GBS were studied by a bioinformatic analysis. It revealed that antigens I/II, which are acquired by horizontal transfer via ICEs, exhibit diversity and are widespread in GBS, in particular in the serotype Ia/ST23 invasive strains. This study aimed at characterizing the impact on GBS biology of proteins encoded by a previously characterized ICE of S. agalactiae (ICE_515_tRNA(Lys)). The production and surface exposition of the antigen I/II encoded by this ICE was examined using RT-PCR and immunoblotting experiments. Surface proteins of ICE_515_tRNA(Lys) were found to contribute to GBS biofilm formation and to fibrinogen binding. Contribution of antigen I/II encoded by SAL_2056 to biofilm formation was also demonstrated. These results highlight the potential for ICEs to spread microbial adhesins between species.
Collapse
Affiliation(s)
- Sarah Chuzeville
- INRA, UMR1128 DynAMic, F-54506 Vandoeuvre-lès-Nancy, France; Université de Lorraine, UMR1128 DynAMic, F-54506 Vandoeuvre-lès-Nancy, France; ANSES Site de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France
| | - Shaynoor Dramsi
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France; CNRS ERL3526, Paris, France
| | - Jean-Yves Madec
- ANSES Site de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France
| | - Marisa Haenni
- ANSES Site de Lyon, Unité Antibiorésistance et Virulence Bactériennes, Lyon, France
| | - Sophie Payot
- INRA, UMR1128 DynAMic, F-54506 Vandoeuvre-lès-Nancy, France; Université de Lorraine, UMR1128 DynAMic, F-54506 Vandoeuvre-lès-Nancy, France.
| |
Collapse
|
13
|
Six A, Bellais S, Bouaboud A, Fouet A, Gabriel C, Tazi A, Dramsi S, Trieu-Cuot P, Poyart C. Srr2, a multifaceted adhesin expressed by ST-17 hypervirulent Group B Streptococcus involved in binding to both fibrinogen and plasminogen. Mol Microbiol 2015; 97:1209-22. [PMID: 26094503 DOI: 10.1111/mmi.13097] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2015] [Indexed: 11/30/2022]
Abstract
The Group B Streptococcus (GBS) 'hypervirulent' ST-17 clone is strongly associated with invasive neonatal meningitis. Comparative genome analyses revealed that the serine-rich repeat (Srr) glycoprotein Srr2 is a cell wall-anchored protein specific for ST-17 strains, the non-ST-17 isolates expressing Srr1. Here, we unravel the binding capacity of GBS Srr proteins to relevant components of the host fibrinolysis pathway. We demonstrate that: (i) Srr2 binds plasminogen and plasmin whereas Srr1 does not; (ii) the ability of ST-17 strains to bind fibrinogen reflects a high level surface display of Srr2 combined with a higher affinity of Srr2 than Srr1 to bind this ligand; and (iii) Srr2 binding to host plasma proteins results in the formation of bacterial aggregates that are efficiently endocytosed by phagocytes. Importantly, we show that Srr2 increased bacterial survival to phagocytic killing and bacterial persistence in a murine model of meningitis. We conclude that Srr2 is a multifaceted adhesin used by the ST-17 clone to hijack ligands of the host coagulation system, thereby contributing to bacterial dissemination and invasiveness, and ultimately to meningitis.
Collapse
Affiliation(s)
- Anne Six
- INSERM U 1016, Institut Cochin, team 'Barriers and Pathogens', Paris, F-75014, France.,CNRS UMR 8104, Paris, F-75014, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, F-75014, France.,DHU 'Risques et grossesse', Assistance Publique Hôpitaux de Paris, Paris, France
| | - Samuel Bellais
- INSERM U 1016, Institut Cochin, team 'Barriers and Pathogens', Paris, F-75014, France.,CNRS UMR 8104, Paris, F-75014, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, F-75014, France.,DHU 'Risques et grossesse', Assistance Publique Hôpitaux de Paris, Paris, France
| | - Abdelouhab Bouaboud
- INSERM U 1016, Institut Cochin, team 'Barriers and Pathogens', Paris, F-75014, France.,CNRS UMR 8104, Paris, F-75014, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, F-75014, France.,DHU 'Risques et grossesse', Assistance Publique Hôpitaux de Paris, Paris, France
| | - Agnès Fouet
- INSERM U 1016, Institut Cochin, team 'Barriers and Pathogens', Paris, F-75014, France.,CNRS UMR 8104, Paris, F-75014, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, F-75014, France.,DHU 'Risques et grossesse', Assistance Publique Hôpitaux de Paris, Paris, France.,Centre National de Référence des Streptocoques, Paris, F-75014, France
| | - Christelle Gabriel
- INSERM U 1016, Institut Cochin, team 'Barriers and Pathogens', Paris, F-75014, France.,CNRS UMR 8104, Paris, F-75014, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, F-75014, France.,DHU 'Risques et grossesse', Assistance Publique Hôpitaux de Paris, Paris, France
| | - Asmaa Tazi
- INSERM U 1016, Institut Cochin, team 'Barriers and Pathogens', Paris, F-75014, France.,CNRS UMR 8104, Paris, F-75014, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, F-75014, France.,DHU 'Risques et grossesse', Assistance Publique Hôpitaux de Paris, Paris, France.,Centre National de Référence des Streptocoques, Paris, F-75014, France.,Hôpitaux Universitaires Paris Centre Cochin-Hôtel Dieu-Broca, Assistance Publique Hôpitaux de Paris, Paris, F-75014, France
| | - Shaynoor Dramsi
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, Paris, F-74016, France.,CNRS ERL3526, Paris, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, Paris, F-74016, France.,CNRS ERL3526, Paris, France
| | - Claire Poyart
- INSERM U 1016, Institut Cochin, team 'Barriers and Pathogens', Paris, F-75014, France.,CNRS UMR 8104, Paris, F-75014, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, F-75014, France.,DHU 'Risques et grossesse', Assistance Publique Hôpitaux de Paris, Paris, France.,Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, Paris, F-74016, France.,CNRS ERL3526, Paris, France.,Centre National de Référence des Streptocoques, Paris, F-75014, France.,Hôpitaux Universitaires Paris Centre Cochin-Hôtel Dieu-Broca, Assistance Publique Hôpitaux de Paris, Paris, F-75014, France
| |
Collapse
|
14
|
Complete Genome Sequence of Streptococcus agalactiae CNCTC 10/84, a Hypervirulent Sequence Type 26 Strain. GENOME ANNOUNCEMENTS 2014; 2:2/6/e01338-14. [PMID: 25540350 PMCID: PMC4276828 DOI: 10.1128/genomea.01338-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Streptococcus agalactiae (group B Streptococcus [GBS]) is a human pathogen with a propensity to cause neonatal infections. We report the complete genome sequence of GBS strain CNCTC 10/84, a hypervirulent clinical isolate frequently used to study GBS pathogenesis. Comparative analysis of this sequence may shed light on novel pathogenic mechanisms.
Collapse
|
15
|
Randis TM, Gelber SE, Hooven TA, Abellar RG, Akabas LH, Lewis EL, Walker LB, Byland LM, Nizet V, Ratner AJ. Group B Streptococcus β-hemolysin/cytolysin breaches maternal-fetal barriers to cause preterm birth and intrauterine fetal demise in vivo. J Infect Dis 2014; 210:265-73. [PMID: 24474814 DOI: 10.1093/infdis/jiu067] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Maternal vaginal colonization with Streptococcus agalactiae (Group B Streptococcus [GBS]) is a precursor to chorioamnionitis, fetal infection, and neonatal sepsis, but the understanding of specific factors in the pathogenesis of ascending infection remains limited. METHODS We used a new murine model to evaluate the contribution of the pore-forming GBS β-hemolysin/cytolysin (βH/C) to vaginal colonization, ascension, and fetal infection. RESULTS Competition assays demonstrated a marked advantage to βH/C-expressing GBS during colonization. Intrauterine fetal demise and/or preterm birth were observed in 54% of pregnant mice colonized with wild-type (WT) GBS and 0% of those colonized with the toxin-deficient cylE knockout strain, despite efficient colonization and ascension by both strains. Robust placental inflammation, disruption of maternal-fetal barriers, and fetal infection were more frequent in animals colonized with WT bacteria. Histopathologic examination revealed bacterial tropism for fetal lung and liver. CONCLUSIONS Preterm birth and fetal demise are likely the direct result of toxin-induced damage and inflammation rather than differences in efficiency of ascension into the upper genital tract. These data demonstrate a distinct contribution of βH/C to GBS chorioamnionitis and subsequent fetal infection in vivo and showcase a model for this most proximal step in GBS pathogenesis.
Collapse
Affiliation(s)
- Tara M Randis
- Department of Pediatrics, Columbia University, New York, New York
| | - Shari E Gelber
- Department of Obstetrics and Gynecology, Weill-Cornell Medical Center, New York, New York
| | - Thomas A Hooven
- Department of Pediatrics, Columbia University, New York, New York
| | - Rosanna G Abellar
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Leor H Akabas
- Department of Pediatrics, Columbia University, New York, New York
| | - Emma L Lewis
- Department of Pediatrics, Columbia University, New York, New York
| | - Lindsay B Walker
- Department of Pediatrics, Columbia University, New York, New York
| | - Leah M Byland
- Department of Pediatrics, Columbia University, New York, New York
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California
| | - Adam J Ratner
- Department of Pediatrics, Columbia University, New York, New York
| |
Collapse
|
16
|
Seo HS, Minasov G, Seepersaud R, Doran KS, Dubrovska I, Shuvalova L, Anderson WF, Iverson TM, Sullam PM. Characterization of fibrinogen binding by glycoproteins Srr1 and Srr2 of Streptococcus agalactiae. J Biol Chem 2013; 288:35982-96. [PMID: 24165132 PMCID: PMC3861647 DOI: 10.1074/jbc.m113.513358] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serine-rich repeat glycoproteins of Gram-positive bacteria comprise a large family of cell wall proteins. Streptococcus agalactiae (group B streptococcus, GBS) expresses either Srr1 or Srr2 on its surface, depending on the strain. Srr1 has recently been shown to bind fibrinogen, and this interaction contributes to the pathogenesis of GBS meningitis. Although strains expressing Srr2 appear to be hypervirulent, no ligand for this adhesin has been described. We now demonstrate that Srr2 also binds human fibrinogen and that this interaction promotes GBS attachment to endothelial cells. Recombinant Srr1 and Srr2 bound fibrinogen in vitro, with affinities of KD = 2.1 × 10−5 and 3.7 × 10−6m, respectively, as measured by surface plasmon resonance spectroscopy. The binding site for Srr1 and Srr2 was localized to tandem repeats 6–8 of the fibrinogen Aα chain. The structures of both the Srr1 and Srr2 binding regions were determined and, in combination with mutagenesis studies, suggest that both Srr1 and Srr2 interact with a segment of these repeats via a “dock, lock, and latch” mechanism. Moreover, properties of the latch region may account for the increased affinity between Srr2 and fibrinogen. Together, these studies identify how greater affinity of Srr2 for fibrinogen may contribute to the increased virulence associated with Srr2-expressing strains.
Collapse
Affiliation(s)
- Ho Seong Seo
- From the Division of Infectious Diseases, Veterans Affairs Medical Center, University of California at San Francisco and the Northern California Institute for Research and Education, San Francisco, California 94121
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Papasergi S, Lanza Cariccio V, Pietrocola G, Domina M, D'Aliberti D, Trunfio MG, Signorino G, Peppoloni S, Biondo C, Mancuso G, Midiri A, Rindi S, Teti G, Speziale P, Felici F, Beninati C. Immunogenic properties of Streptococcus agalactiae FbsA fragments. PLoS One 2013; 8:e75266. [PMID: 24086487 PMCID: PMC3782484 DOI: 10.1371/journal.pone.0075266] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/14/2013] [Indexed: 11/18/2022] Open
Abstract
Several species of Gram-positive bacteria can avidly bind soluble and surface-associated fibrinogen (Fng), a property that is considered important in the pathogenesis of human infections. To gain insights into the mechanism by which group B Streptococcus (GBS), a frequent neonatal pathogen, interacts with Fng, we have screened two phage displayed genomic GBS libraries. All of the Fng-binding phage clones contained inserts encoding fragments of FbsA, a protein displaying multiple repeats. Since the functional role of this protein is only partially understood, representative fragments were recombinantly expressed and analyzed for Fng binding affinity and ability to induce immune protection against GBS infection. Maternal immunization with 6pGST, a fragment containing five repeats, significantly protected mouse pups against lethal GBS challenge and these protective effects could be recapitulated by administration of anti-6pGST serum from adult animals. Notably, a monoclonal antibody that was capable of neutralizing Fng binding by 6pGST, but not a non-neutralizing antibody, could significantly protect pups against lethal GBS challenge. These data suggest that FbsA-Fng interaction promotes GBS pathogenesis and that blocking such interaction is a viable strategy to prevent or treat GBS infections.
Collapse
|
18
|
Oliveira R, Domingos RF, Siqueira GH, Fernandes LG, Souza NM, Vieira ML, de Morais ZM, Vasconcellos SA, Nascimento ALTO. Adhesins of Leptospira interrogans mediate the interaction to fibrinogen and inhibit fibrin clot formation in vitro. PLoS Negl Trop Dis 2013; 7:e2396. [PMID: 24009788 PMCID: PMC3757074 DOI: 10.1371/journal.pntd.0002396] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 07/19/2013] [Indexed: 12/31/2022] Open
Abstract
We report in this work that Leptospira strains, virulent L. interrogans serovar Copenhageni, attenuated L. interrogans serovar Copenhageni and saprophytic L. biflexa serovar Patoc are capable of binding fibrinogen (Fg). The interaction of leptospires with Fg inhibits thrombin- induced fibrin clot formation that may affect the haemostatic equilibrium. Additionally, we show that plasminogen (PLG)/plasmin (PLA) generation on the surface of Leptospira causes degradation of human Fg. The data suggest that PLA-coated leptospires were capable to employ their proteolytic activity to decrease one substrate of the coagulation cascade. We also present six leptospiral adhesins and PLG- interacting proteins, rLIC12238, Lsa33, Lsa30, OmpL1, rLIC11360 and rLIC11975, as novel Fg-binding proteins. The recombinant proteins interact with Fg in a dose-dependent and saturable fashion when increasing protein concentration was set to react to a fix human Fg concentration. The calculated dissociation equilibrium constants (KD) of these reactions ranged from 733.3±276.8 to 128±89.9 nM for rLIC12238 and Lsa33, respectively. The interaction of recombinant proteins with human Fg resulted in inhibition of fibrin clot by thrombin-catalyzed reaction, suggesting that these versatile proteins could mediate Fg interaction in Leptospira. Our data reveal for the first time the inhibition of fibrin clot by Leptospira spp. and presents adhesins that could mediate these interactions. Decreasing fibrin clot would cause an imbalance of the coagulation cascade that may facilitate bleeding and help bacteria dissemination Leptospirosis is probably the most widespread zoonosis in the world. Caused by spirochaetes of the genus Leptospira, it has greater incidence in tropical and subtropical regions. The disease has become prevalent in cities with sanitation problems and a large population of urban rodent reservoirs, which contaminate the environment through their urine. Understanding the mechanisms involved in pathogenesis of leptospirosis should contribute to new strategies that would help fight the disease. We show in this work that Leptospira strains, virulent, attenuated or saprophytic are capable of binding fibrinogen (Fg). The interaction of leptospires with Fg inhibits the formation of fibrin clot that may result of an imbalance in the haemostatic equilibrium. In addition, we show that plasminogen (PLG)/plasmin (PLA) generation on the surface of leptospires can lead to Fg degradation, showing evidence of possible route of fibrinolysis in leptospirosis. We also present six leptospiral proteins, as novel Fg-binding proteins, capable of inhibiting fibrin clot formation by thrombin-catalyzed reaction, suggesting that in Leptospira these multifunctional proteins could mediate Fg interaction. Our data suggest possible mechanisms that leptospires could employ to affect the coagulation cascade and fibrinolytic system that might lead to bacteria spreading.
Collapse
Affiliation(s)
- Rosane Oliveira
- Centro de Biotecnologia, Instituto Butantan, São Paulo, São Paulo, Brazil
- Programa Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Renan F. Domingos
- Centro de Biotecnologia, Instituto Butantan, São Paulo, São Paulo, Brazil
- Programa Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Gabriela H. Siqueira
- Centro de Biotecnologia, Instituto Butantan, São Paulo, São Paulo, Brazil
- Programa Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Luis G. Fernandes
- Centro de Biotecnologia, Instituto Butantan, São Paulo, São Paulo, Brazil
- Programa Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Natalie M. Souza
- Centro de Biotecnologia, Instituto Butantan, São Paulo, São Paulo, Brazil
- Programa Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Monica L. Vieira
- Centro de Biotecnologia, Instituto Butantan, São Paulo, São Paulo, Brazil
| | - Zenaide M. de Morais
- Laboratorio de Zoonoses Bacterianas do VPS, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Silvio A. Vasconcellos
- Laboratorio de Zoonoses Bacterianas do VPS, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Ana L. T. O. Nascimento
- Centro de Biotecnologia, Instituto Butantan, São Paulo, São Paulo, Brazil
- Programa Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- * E-mail: .
| |
Collapse
|
19
|
Danne C, Dramsi S. Pili of gram-positive bacteria: roles in host colonization. Res Microbiol 2012; 163:645-58. [PMID: 23116627 DOI: 10.1016/j.resmic.2012.10.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 10/11/2012] [Indexed: 02/06/2023]
Abstract
In the last decade, pili, which are encoded within pathogenicity islands, have been found in many Gram-positive bacteria, including the major streptococcal and enterococcal pathogens. These long proteinaceous polymers extending from the bacterial surface are constituted of covalently linked pilin subunits, which play major roles in adhesion and host colonization. They are also involved in biofilm formation, a characteristic life-style of the bacteria constituting the oral flora. Pili are highly immunogenic structures that are under the selective pressure of host immune responses. Indeed, pilus expression was found to be heterogeneous in several bacteria with the co-existence of two subpopulations expressing various levels of pili. The molecular mechanisms underlying this complex regulation are poorly characterized except for Streptococcus pneumoniae. In this review, we will discuss the roles of Gram-positive bacteria pili in adhesion to host extracellular matrix proteins, tissue tropism, biofilm formation, modulation of innate immune responses and their contribution to virulence, and in a second part the regulation of their expression. This overview should help to understand the rise of pili as an intensive field of investigation and pinpoints the areas that need further study.
Collapse
Affiliation(s)
- Camille Danne
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-positif, Paris F-75015, France
| | | |
Collapse
|