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Persson A, Koivula T, Jacobsson S, Stenmark B. Diverse proinflammatory response in pharyngeal epithelial cells upon interaction with Neisseria meningitidis carriage and invasive isolates. BMC Infect Dis 2024; 24:286. [PMID: 38443838 PMCID: PMC10916014 DOI: 10.1186/s12879-024-09186-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 03/01/2024] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND Invasive meningococcal disease (IMD), including sepsis and meningitis, can develop when Neisseria meningitidis bacteria breach the barrier and gain access to the circulation. While IMD is a rare outcome of bacterial exposure, colonization of the oropharynx is present in approximately 10% of the human population. This asymptomatic carriage can be long or short term, and it is unknown which determining factors regulate bacterial colonization. Despite descriptions of many bacterial virulence factors and recent advances in detailed genetic identification and characterization of bacteria, the factors mediating invasion and disease vs. asymptomatic carriage following bacterial colonization remain unknown. The pharyngeal epithelia play a role in the innate immune defense against pathogens, and the aim of this study was to investigate the proinflammatory response of pharyngeal epithelial cells following meningococcal exposure to describe the potential inflammatory mediation performed during the initial host‒pathogen interaction. Clinically relevant isolates of serogroups B, C, W and Y, derived from patients with meningococcal disease as well as asymptomatic carriers, were included in the study. RESULTS The most potent cellular response with proinflammatory secretion of TNF, IL-6, CXCL8, CCL2, IL-1β and IL-18 was found in response to invasive serogroup B isolates. This potent response pattern was also mirrored by increased bacterial adhesion to cells as well as induced cell death. It was, however, only with serogroup B isolates where the most potent cellular response was toward the IMD isolates. In contrast, the most potent cellular response using serogroup Y isolates was directed toward the carriage isolates rather than the IMD isolates. In addition, by comparing isolates from outbreaks in Sweden (epidemiologically linked and highly genetically similar), we found the most potent proinflammatory response in cells exposed to carriage isolates rather than the IMD isolates. CONCLUSION Although certain expected correlations between host‒pathogen interactions and cellular proinflammatory responses were found using IMD serogroup B isolates, our data indicate that carriage isolates invoke stronger proinflammatory activation of the epithelial lining than IMD isolates.
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Affiliation(s)
- Alexander Persson
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
| | - Therese Koivula
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Susanne Jacobsson
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Bianca Stenmark
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
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Interactions and Signal Transduction Pathways Involved during Central Nervous System Entry by Neisseria meningitidis across the Blood-Brain Barriers. Int J Mol Sci 2020; 21:ijms21228788. [PMID: 33233688 PMCID: PMC7699760 DOI: 10.3390/ijms21228788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/18/2020] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative diplococcus Neisseria meningitidis, also called meningococcus, exclusively infects humans and can cause meningitis, a severe disease that can lead to the death of the afflicted individuals. To cause meningitis, the bacteria have to enter the central nervous system (CNS) by crossing one of the barriers protecting the CNS from entry by pathogens. These barriers are represented by the blood–brain barrier separating the blood from the brain parenchyma and the blood–cerebrospinal fluid (CSF) barriers at the choroid plexus and the meninges. During the course of meningococcal disease resulting in meningitis, the bacteria undergo several interactions with host cells, including the pharyngeal epithelium and the cells constituting the barriers between the blood and the CSF. These interactions are required to initiate signal transduction pathways that are involved during the crossing of the meningococci into the blood stream and CNS entry, as well as in the host cell response to infection. In this review we summarize the interactions and pathways involved in these processes, whose understanding could help to better understand the pathogenesis of meningococcal meningitis.
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Schubert-Unkmeir A. Molecular mechanisms involved in the interaction of Neisseria meningitidis with cells of the human blood-cerebrospinal fluid barrier. Pathog Dis 2017; 75:3061359. [PMID: 28334198 DOI: 10.1093/femspd/ftx023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/02/2017] [Indexed: 11/15/2022] Open
Abstract
Neisseria meningitidis is one of the most common aetiological agents of bacterial meningitis, affecting predominantly children and young adults. The interaction of N. meningitidis with human endothelial cells lining blood vessels of the blood-cerebrospinal fluid barrier (B-CSFB) is critical for meningitis development. In recent decades, there has been a significant increase in understanding of the molecular mechanisms involved in the interaction of N. meningitidis with brain vascular cells. In this review, we will describe how N. meningitidis adheres to the brain vasculature, may enter inside these cells, hijack receptor signalling pathways and alter host-cell responses in order to traverse the B-CSFB.
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Klein RS, Garber C, Howard N. Infectious immunity in the central nervous system and brain function. Nat Immunol 2017; 18:132-141. [PMID: 28092376 DOI: 10.1038/ni.3656] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/02/2016] [Indexed: 11/09/2022]
Abstract
Inflammation is emerging as a critical mechanism underlying neurological disorders of various etiologies, yet its role in altering brain function as a consequence of neuroinfectious disease remains unclear. Although acute alterations in mental status due to inflammation are a hallmark of central nervous system (CNS) infections with neurotropic pathogens, post-infectious neurologic dysfunction has traditionally been attributed to irreversible damage caused by the pathogens themselves. More recently, studies indicate that pathogen eradication within the CNS may require immune responses that interfere with neural cell function and communication without affecting their survival. In this Review we explore inflammatory processes underlying neurological impairments caused by CNS infection and discuss their potential links to established mechanisms of psychiatric and neurodegenerative diseases.
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Affiliation(s)
- Robyn S Klein
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Charise Garber
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nicole Howard
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Besbes A, Le Goff S, Antunes A, Terrade A, Hong E, Giorgini D, Taha MK, Deghmane AE. Hyperinvasive Meningococci Induce Intra-nuclear Cleavage of the NF-κB Protein p65/RelA by Meningococcal IgA Protease. PLoS Pathog 2015; 11:e1005078. [PMID: 26241037 PMCID: PMC4524725 DOI: 10.1371/journal.ppat.1005078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 07/10/2015] [Indexed: 11/30/2022] Open
Abstract
Differential modulation of NF-κB during meningococcal infection is critical in innate immune response to meningococcal disease. Non-invasive isolates of Neisseria meningitidis provoke a sustained NF-κB activation in epithelial cells. However, the hyperinvasive isolates of the ST-11 clonal complex (ST-11) only induce an early NF-κB activation followed by a sustained activation of JNK and apoptosis. We show that this temporal activation of NF-κB was caused by specific cleavage at the C-terminal region of NF-κB p65/RelA component within the nucleus of infected cells. This cleavage was mediated by the secreted 150 kDa meningococcal ST-11 IgA protease carrying nuclear localisation signals (NLS) in its α-peptide moiety that allowed efficient intra-nuclear transport. In a collection of non-ST-11 healthy carriage isolates lacking NLS in the α-peptide, secreted IgA protease was devoid of intra-nuclear transport. This part of iga polymorphism allows non-invasive isolates lacking NLS, unlike hyperinvasive ST-11 isolates of N. meningitides habouring NLS in their α-peptide, to be carried asymptomatically in the human nasopharynx through selective eradication of their ability to induce apoptosis in infected epithelial cells.
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Affiliation(s)
- Anissa Besbes
- Institut Pasteur, Invasive Bacterial Infections Unit, Paris, France
| | - Salomé Le Goff
- Institut Pasteur, Invasive Bacterial Infections Unit, Paris, France
| | - Ana Antunes
- Institut Pasteur, Invasive Bacterial Infections Unit, Paris, France
| | - Aude Terrade
- Institut Pasteur, Invasive Bacterial Infections Unit, Paris, France
| | - Eva Hong
- Institut Pasteur, Invasive Bacterial Infections Unit, Paris, France
| | - Dario Giorgini
- Institut Pasteur, Invasive Bacterial Infections Unit, Paris, France
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Khairalla AS, Omer SA, Mahdavi J, Aslam A, Dufailu OA, Self T, Jonsson AB, Geörg M, Sjölinder H, Royer PJ, Martinez-Pomares L, Ghaemmaghami AM, Wooldridge KG, Oldfield NJ, Ala'Aldeen DAA. Nuclear trafficking, histone cleavage and induction of apoptosis by the meningococcal App and MspA autotransporters. Cell Microbiol 2015; 17:1008-20. [PMID: 25600171 PMCID: PMC5024080 DOI: 10.1111/cmi.12417] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 12/18/2014] [Accepted: 01/13/2015] [Indexed: 01/13/2023]
Abstract
Neisseria meningitidis, a major cause of bacterial meningitis and septicaemia, secretes multiple virulence factors, including the adhesion and penetration protein (App) and meningococcal serine protease A (MspA). Both are conserved, immunogenic, type Va autotransporters harbouring S6‐family serine endopeptidase domains. Previous work suggested that both could mediate adherence to human cells, but their precise contribution to meningococcal pathogenesis was unclear. Here, we confirm that App and MspA are in vivo virulence factors since human CD46‐expressing transgenic mice infected with meningococcal mutants lacking App, MspA or both had improved survival rates compared with mice infected with wild type. Confocal imaging showed that App and MspA were internalized by human cells and trafficked to the nucleus. Cross‐linking and enzyme‐linked immuno assay (ELISA) confirmed that mannose receptor (MR), transferrin receptor 1 (TfR1) and histones interact with MspA and App. Dendritic cell (DC) uptake could be blocked using mannan and transferrin, the specific physiological ligands for MR and TfR1, whereas in vitro clipping assays confirmed the ability of both proteins to proteolytically cleave the core histone H3. Finally, we show that App and MspA induce a dose‐dependent increase in DC death via caspase‐dependent apoptosis. Our data provide novel insights into the roles of App and MspA in meningococcal infection.
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Affiliation(s)
| | - Sherko A Omer
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Jafar Mahdavi
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Akhmed Aslam
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Osman A Dufailu
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Tim Self
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Ann-Beth Jonsson
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Miriam Geörg
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Hong Sjölinder
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | | | | | | | | | - Neil J Oldfield
- School of Life Sciences, University of Nottingham, Nottingham, UK
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7
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Deciphering the contribution of human meningothelial cells to the inflammatory and antimicrobial response at the meninges. Infect Immun 2013; 81:4299-310. [PMID: 24002066 DOI: 10.1128/iai.00477-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have investigated the response of primary human meningothelial cells to Neisseria meningitidis. Through a transcriptome analysis, we provide a comprehensive examination of the response of meningothelial cells to bacterial infection. A wide range of chemokines are elicited which act to attract and activate the main players of innate and adaptive immunity. We showed that meningothelial cells expressed a high level of Toll-like receptor 4 (TLR4), and, using a gene silencing strategy, we demonstrated the contribution of this pathogen recognition receptor in meningothelial cell activation. Secretion of interleukin-6 (IL-6), CXCL10, and CCL5 was almost exclusively TLR4 dependent and relied on MyD88 and TRIF adaptor cooperation. In contrast, IL-8 induction was independent of the presence of TLR4, MyD88, and TRIF. Transcription factors NF-κB p65, p38 mitogen-activated protein kinase (MAPK), Jun N-terminal protein kinase (JNK1), IRF3, and IRF7 were activated after contact with bacteria. Interestingly, the protein kinase IRAK4 was found to play a minor role in the meningothelial cell response to Neisseria infection. Our work highlights the role of meningothelial cells in the development of an immune response and inflammation in the central nervous system (CNS) in response to meningococcal infection. It also sheds light on the complexity of intracellular signaling after TLR triggering.
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8
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Bernardini G, Braconi D, Lusini P, Santucci A. Post-genomics of Neisseria meningitidis: an update. Expert Rev Proteomics 2011; 8:803-11. [PMID: 22087663 DOI: 10.1586/epr.11.59] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neisseria meningitidis infection still remains a major life-threatening bacterial disease worldwide. The availability of bacterial genomic sequences generated a paradigm shift in microbiological and vaccines sciences, and post-genomics (comparative genomics, functional genomics, proteomics and a combination/evolution of these techniques) played important roles in elucidating bacterial biological complexity and pathogenic traits, at the same time accelerating the development of therapeutic drugs and vaccines. This article summarizes the most recent technological and scientific advances in meningococcal biology and pathogenesis aimed at the development and characterization of vaccines against the pathogenic meningococci.
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Affiliation(s)
- Giulia Bernardini
- Dipartimento di Biologia Molecolare, via Fiorentina 1, Università degli Studi di Siena, 53100 Siena, Italy
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Wong HEE, Li MS, Kroll JS, Hibberd ML, Langford PR. Genome wide expression profiling reveals suppression of host defence responses during colonisation by Neisseria meningitides but not N. lactamica. PLoS One 2011; 6:e26130. [PMID: 22028815 PMCID: PMC3197596 DOI: 10.1371/journal.pone.0026130] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 09/20/2011] [Indexed: 11/22/2022] Open
Abstract
Both Neisseria meningitidis and the closely related bacterium Neisseria lactamica colonise human nasopharyngeal mucosal surface, but only N. meningitidis invades the bloodstream to cause potentially life-threatening meningitis and septicaemia. We have hypothesised that the two neisserial species differentially modulate host respiratory epithelial cell gene expression reflecting their disease potential. Confluent monolayers of 16HBE14 human bronchial epithelial cells were exposed to live and/or dead N. meningitidis (including capsule and pili mutants) and N. lactamica, and their transcriptomes were compared using whole genome microarrays. Changes in expression of selected genes were subsequently validated using Q-RT-PCR and ELISAs. Live N. meningitidis and N. lactamica induced genes involved in host energy production processes suggesting that both bacterial species utilise host resources. N. meningitidis infection was associated with down-regulation of host defence genes. N. lactamica, relative to N. meningitidis, initiates up-regulation of proinflammatory genes. Bacterial secreted proteins alone induced some of the changes observed. The results suggest N. meningitidis and N. lactamica differentially regulate host respiratory epithelial cell gene expression through colonisation and/or protein secretion, and that this may contribute to subsequent clinical outcomes associated with these bacteria.
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Affiliation(s)
- Hazel En En Wong
- Infectious Diseases, Genome Institute of Singapore, Singapore, Singapore
- Section of Paediatrics, Imperial College London, London, United Kingdom
| | - Ming-Shi Li
- Section of Paediatrics, Imperial College London, London, United Kingdom
| | - J. Simon Kroll
- Section of Paediatrics, Imperial College London, London, United Kingdom
| | - Martin L. Hibberd
- Infectious Diseases, Genome Institute of Singapore, Singapore, Singapore
| | - Paul R. Langford
- Section of Paediatrics, Imperial College London, London, United Kingdom
- * E-mail:
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10
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Xin X, Fan B, Flammer J, Miller NR, Jaggi GP, Killer HE, Meyer P, Neutzner A. Meningothelial cells react to elevated pressure and oxidative stress. PLoS One 2011; 6:e20142. [PMID: 21611150 PMCID: PMC3096659 DOI: 10.1371/journal.pone.0020142] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 04/21/2011] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Meningothelial cells (MECs) are the cellular components of the meninges enveloping the brain. Although MECs are not fully understood, several functions of these cells have been described. The presence of desmosomes and tight junctions between MECs hints towards a barrier function protecting the brain. In addition, MECs perform endocytosis and, by the secretion of cytokines, are involved in immunological processes in the brain. However, little is known about the influence of pathological conditions on MEC function; e.g., during diseases associated with elevated intracranial pressure, hypoxia or increased oxidative stress. METHODS We studied the effect of elevated pressure, hypoxia, and oxidative stress on immortalized human as well as primary porcine MECs. We used MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) bioreduction assays to assess the proliferation of MECs in response to treatment and compared to untreated control cells. To assess endocytotic activity, the uptake of fluorescently labeled latex beads was analyzed by fluorescence microscopy. RESULTS We found that exposure of MECs to elevated pressure caused significant cellular proliferation and a dramatic decrease in endocytotic activity. In addition, mild oxidative stress severely inhibited endocytosis. CONCLUSION Elevated pressure and oxidative stress impact MEC physiology and might therefore influence the microenvironment of the subarachnoid space and thus the cerebrospinal fluid within this compartment with potential negative impact on neuronal function.
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Affiliation(s)
- Xiaorong Xin
- Department of Biomedicine, Ocular Pharmacology and Physiology and Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| | - Bin Fan
- Department of Biomedicine, Ocular Pharmacology and Physiology and Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| | - Josef Flammer
- Department of Biomedicine, Ocular Pharmacology and Physiology and Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| | - Neil R. Miller
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Gregor P. Jaggi
- Department of Ophthalmology, Kantonsspital Aarau, Aarau, Switzerland
| | | | - Peter Meyer
- Department of Biomedicine, Ocular Pharmacology and Physiology and Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| | - Albert Neutzner
- Department of Biomedicine, Ocular Pharmacology and Physiology and Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
- * E-mail:
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11
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Schubert-Unkmeir A, Slanina H, Frosch M. Mammalian cell transcriptome in response to meningitis-causing pathogens. Expert Rev Mol Diagn 2010; 9:833-42. [PMID: 19895228 DOI: 10.1586/erm.09.68] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bacterial meningitis continues to be a major cause of mortality and morbidity, despite improved antimicrobial therapy. A key factor that contributes to this situation is the incomplete understanding of its pathogenesis. High-throughput methods (e.g., DNA microarray technology) can provide a holistic picture of the transcriptional events that underlie the host response to bacterial infections, including that during bacterial meningitis. Since 2001, several studies have been reported on the cellular host's responses to infections with Neisseria meningitidis and Streptococcus pneumoniae (the leading causes of bacterial meningitis) using DNA microarrays and have described numerous differentially expressed genes. The present review summarizes the main recent findings with gene expression analyses in the field of bacterial meningitis. Experiments that defined a common host response, as well as pathogen-specific host responses, will be discussed. This review will also outline the contributions of global gene analyses to our understanding of the pathophysiology of bacterial meningitis.
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Affiliation(s)
- Alexandra Schubert-Unkmeir
- Institute of Hygiene and Microbiology, University of Wuerzburg, Josef-Schneider-Str.2, 97080 Wuerzburg, Germany.
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12
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Meningococcal porin PorB prevents cellular apoptosis in a toll-like receptor 2- and NF-kappaB-independent manner. Infect Immun 2009; 78:994-1003. [PMID: 20028813 DOI: 10.1128/iai.00156-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Meningococcal porin PorB is an inhibitor of apoptosis induced via the intrinsic pathway in various cell types. This effect is attributed to prevention of mitochondrial depolarization and of subsequent release of proapoptotic mitochondrial factors. To determine whether apoptosis is globally inhibited by PorB, we compared the intrinsic and extrinsic pathways in HeLa cells. Interestingly, PorB does not prevent extrinsic apoptosis induced by tumor necrosis factor alpha plus cycloheximide, suggesting a unique mitochondrial pathway specificity. Several intracellular factors regulated by NF-kappaB, including members of the Bcl-2 family and of the inhibitor of apoptosis (IAP) family, play major roles in controlling apoptosis, and some of them are thought to contribute to the antiapoptotic effect of the gonococcal porin, PIB. However, most of the members of the Bcl-2 family and the IAP family are not induced by meningococcal PorB in HeLa cells, with the exception of Bfl-1/A1. Interestingly, PorB does not induce NF-kappaB activation in HeLa cells, likely due to a lack of Toll-like receptor 2 (TLR2) expression in these cells. Bfl-1/A1 expression is also regulated by CBF1, a nuclear component of the Notch signaling pathway, independent of NF-kappaB activation. Since HeLa cells are protected by PorB from intrinsic apoptosis events, regardless of TLR2 and NF-kappaB expression, the possibility of a contribution of alternative signaling pathways to this effect cannot be excluded. In this paper, we describe an initial dissection of the cascade of cellular events involved in the antiapoptotic effect of PorB in the absence of TLR2.
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Bernardini G, Braconi D, Lusini P, Santucci A. Postgenomics of Neisseria meningitidis: an update. Expert Rev Proteomics 2009; 6:135-43. [PMID: 19385941 DOI: 10.1586/epr.09.3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neisseria meningitidis infection represents a major life-threatening bacterial disease worldwide. Genomics has revolutionized every aspect of the field of microbiology. As a consequence of genome sequencing, the postgenomic era commenced 15 years ago. Comparative genomics, functional genomics and proteomics, as well as a combination of these techniques, will play important roles in providing vital information regarding bacterial biological complexity and pathogenic traits, and accelerate the development of therapeutic drugs and vaccines for combating infections. This review summarizes the current knowledge regarding different approaches aimed to shed light on meningococcal biology and pathogenesis, and to accelerate the development and characterization of vaccines against pathogenic meningococci.
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Affiliation(s)
- Giulia Bernardini
- Dipartimento di Biologia Molecolare, Via Fiorentina 1, Università degli Studi di Siena, 53100 Siena, Italy.
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14
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Li Y, Wooldridge KG, Javed MA, Tang CM, Ala'aldeen DAA. Secreted proteins of Neisseria meningitidis protect mice against infection. Vaccine 2009; 27:2320-5. [PMID: 19428846 DOI: 10.1016/j.vaccine.2009.02.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 01/21/2009] [Accepted: 02/11/2009] [Indexed: 11/28/2022]
Abstract
We addressed the hypothesis that meningococcal secreted proteins (MSPs) can elicit protective immunity against meningococcal disease. Endotoxin-depleted MSP preparations were used to immunise a group of 15 six-week-old BALB/c mice (25microg MSPs/dose mixed with Freund's complete adjuvant) on days 0, 14 and 21. Mice were challenged 2 weeks later with 10(7) colony forming units of live Neisseria meningitidis strain MC58 (serogroup B, ET-5). Negative and positive control groups of 15 mice each were injected with adjuvant only, or a live attenuated strain of MC58, respectively. Seven out of 15 mice (47%) from the negative control group died after 72h of challenge, whereas none of test or positive control group died. Protection afforded by the anti-MSP immune response can be at least partly attributed to complement-mediated bacterial lysis, detectable in vitro using the serum of immunised mice. Murine anti-MC58 MSP sera were bactericidal against homologous and five unrelated ET-5 serogroup B strains. However, failed to kill strains from other hypervirulent clonal lineages belonging to the same or different serogroups, despite the presence of cross-reactive antibodies detectable by immunoblotting. Similar sera raised against MSPs from an isolate belonging to the ET-37 electropherotype lineage were bactericidal against all tested isolates of this lineage and, in addition, against some but not all isolates belonging to the ET-5 lineage. FACS analysis of intact bacteria treated with anti-MSPs confirmed surface-binding of antibodies.
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Affiliation(s)
- Yanwen Li
- Centre for Molecular Microbiology and Infection, Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK
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15
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Abstract
The meningococcal Opa proteins play an important role in pathogenesis by mediating invasion of human cells. The aim of this investigation was to determine whether carried and disease-associated meningococci possess different Opa repertoires and whether the diversity of these proteins is associated with clinical severity of disease. Opa repertoires in 227 disease-associated meningococci, isolated in the United Kingdom over a period of 6 years, were compared to the repertoires in 190 asymptomatically carried meningococci isolated in the United Kingdom from a contemporary, nonepidemic period. Multidimensional scaling (MDS) was employed to investigate the association between Opa repertoires and multilocus sequence typing (MLST) genotypes. Associations with clinical severity were also analyzed statistically. High levels of diversity were observed in opa alleles, variable regions, and repertoires, and MDS revealed that MLST genotypes were strongly associated with particular Opa repertoires. Individual Opa proteins or repertoires were not associated with clinical severity, though there was a trend toward an association with the opaD locus. Meningococcal Opa repertoire is strongly linked to MLST genotype irrespective of epidemiological sampling and therefore correlates with invasiveness. It is not, however, strongly associated with severity of meningococcal disease.
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16
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Oldfield NJ, Bland SJ, Taraktsoglou M, Dos Ramos FJ, Robinson K, Wooldridge KG, Ala'Aldeen DAA. T-cell stimulating protein A (TspA) of Neisseria meningitidis is required for optimal adhesion to human cells. Cell Microbiol 2007; 9:463-78. [PMID: 16965515 DOI: 10.1111/j.1462-5822.2006.00803.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
T-cell stimulating protein A (TspA) is an immunogenic, T-cell and B-cell stimulating protein of Neisseria meningitidis. Sequence similarity between TspA and FimV, a Pseudomonas aeruginosa protein involved in twitching motility, suggested a link between TspA and type IV pili (Tfp). To determine the role of TspA an isogenic deletion mutant was created. Loss of TspA did not affect twitching motility or piliation indicating that there are functional differences between TspA and FimV. Mutation of tspA led to a significant reduction in adhesion of meningococci to meningothelial and HEp-2 cells, which was not due to a lack of transcription of adjacent genes or pilC1. Other Tfp-mediated phenotypes (i.e. auto-aggregation and transformation competence) were not altered. Our results indicate that the role of TspA in adhesion is unlikely to be directly linked to the function of Tfp. TspA was expressed by all N. meningitidis and Neisseria polysaccharea strains examined but not by Neisseria gonorrhoeae or Neisseria lactamica, although sequences with homology to tspA were present in their genomes. In summary, TspA is a highly conserved antigen that is required for optimal adhesion of meningococci to human cells.
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Affiliation(s)
- Neil J Oldfield
- Molecular Bacteriology and Immunology Group, Institute of Infection, Immunity and Inflammation, School of Molecular Medical Sciences, Queen's Medical Centre, University of Nottingham, UK
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Schubert-Unkmeir A, Sokolova O, Panzner U, Eigenthaler M, Frosch M. Gene expression pattern in human brain endothelial cells in response to Neisseria meningitidis. Infect Immun 2006; 75:899-914. [PMID: 17130252 PMCID: PMC1828482 DOI: 10.1128/iai.01508-06] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
To extend our knowledge of target proteins in endothelial cells infected with the meningitis-causing pathogen Neisseria meningitidis, we characterized the interaction between the bacterial and human brain microvascular endothelial cell (HBMEC) monolayers. By use of human cDNA microarrays, transcriptional analysis revealed distinct responses to 4 and 8 h of infection. We also addressed the question of whether the major virulence factor of meningococci, i.e., the capsule, influences the host cell response. Of the 1,493 (at 4 h postinfection) and 1,246 (at 8 h postinfection) genes with altered expression upon bacterial contact, about 49.4% and 45%, respectively, depended on capsule expression. In particular, we identified an increase of expression for genes encoding proteins involved in bacterial adhesion and invasion. High levels of apoptosis-related gene (bad, bak, asp, and immediate-early response gene 1) expression could also be detected in infected cells. Further analyses confirmed that HBMECs displayed several hallmarks of apoptosis in response to N. meningitidis infection, namely, phosphatidylserine translocation and activation of caspase 3 and AMP-activated protein kinase alpha. Moreover, several differentially regulated genes not previously known to respond to meningococcal infection were identified. Of these, genes encoding cell adhesion proteins (CD44, CD98, and CD99), genes involved in downstream signaling of integrins (integrin-linked kinase, mitogen-activated protein kinase kinase 1, and mitogen-activated protein kinase kinase kinase 10) as well as negative regulators of these pathways (dual-specificity phosphatases 1, 5, and 14 and G protein pathway suppressor 2), and genes involved in cytoskeleton reorganization (those encoding Arp2/3, p34-arc, actinin alpha 1, vasodilatator-stimulated protein, and Wiskott-Aldrich syndrome protein) were the most prominent. This global transcriptional analysis creates a new platform for further molecular and cellular analysis of the interaction between N. meningitidis and target cells.
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Linhartova I, Basler M, Ichikawa J, Pelicic V, Osicka R, Lory S, Nassif X, Sebo P. Meningococcal adhesion suppresses proapoptotic gene expression and promotes expression of genes supporting early embryonic and cytoprotective signaling of human endothelial cells. FEMS Microbiol Lett 2006; 263:109-18. [PMID: 16958858 DOI: 10.1111/j.1574-6968.2006.00407.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Neisseria meningitidis colonizes the human nasopharynx and occasionally causes lethal or damaging septicemia and meningitis. Here, we examined the adherence-mediated signaling of meningococci to human cells by comparing gene expression profiles of human umbilical vein endothelial cells (HUVEC) infected by adherent wild-type, frpC-deficient mutant, or the nonadherent (DeltapilD) N. meningitidis. Pili-mediated adhesion of meningococci resulted in alterations of expression levels of human genes known to regulate apoptosis, cell proliferation, inflammatory response, adhesion and genes for signaling pathway proteins such as TGF-beta/Smad, Wnt/beta-catenin and Notch/Jagged. This reveals that adhering piliated meningocci manipulate host signaling pathways controlling cell proliferation while establishing a commensal relationship.
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Affiliation(s)
- Irena Linhartova
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
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Fowler MI, Yin KYHW, Humphries HE, Heckels JE, Christodoulides M. Comparison of the inflammatory responses of human meningeal cells following challenge with Neisseria lactamica and with Neisseria meningitidis. Infect Immun 2006; 74:6467-78. [PMID: 16954390 PMCID: PMC1695519 DOI: 10.1128/iai.00644-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rationale for the present study was to determine how different species of bacteria interact with cells of the human meninges in order to gain information that would have broad relevance to understanding aspects of the innate immune response in the brain. Neisseria lactamica is an occasional cause of meningitis in humans, and in this study we investigated the in vitro interactions between N. lactamica and cells derived from the leptomeninges in comparison with the closely related organism Neisseria meningitidis, a major cause of meningitis worldwide. N. lactamica adhered specifically to meningioma cells, but the levels of adherence were generally lower than those with N. meningitidis. Meningioma cells challenged with N. lactamica and N. meningitidis secreted significant amounts of the proinflammatory cytokine interleukin-6 (IL-6), the C-X-C chemokine IL-8, and the C-C chemokines monocyte chemoattractant protein 1 (MCP-1) and RANTES, but it secreted very low levels of the cytokine growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF). Thus, meningeal cells are involved in the innate host response to Neisseria species that are capable of entering the cerebrospinal fluid. The levels of IL-8 and MCP-1 secretion induced by both bacteria were essentially similar. By contrast, N. lactamica induced significantly lower levels of IL-6 than N. meningitidis. Challenge with the highest concentration of N. lactamica (10(8) CFU) induced a small but significant down-regulation of RANTES secretion, which was not observed with lower concentrations of bacteria. N. meningitidis (10(6) to 10(8) CFU) also down-regulated RANTES secretion, but this effect was significantly greater than that observed with N. lactamica. Although both bacteria were unable to invade meningeal cells directly, host cells remained viable on prolonged challenge with N. lactamica, whereas N. meningitidis induced death; the mechanism was overwhelming necrosis with no significant apoptosis. It is likely that differential expression of modulins between N. lactamica and N. meningitidis contributes to these observed differences in pathogenic potential.
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Affiliation(s)
- Mark I Fowler
- Molecular Microbiology Group, Division of Infection, Inflammation and Repair, Mailpoint 814, University of Southampton Medical School, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, United Kingdom
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van Ulsen P, Tommassen J. Protein secretion and secreted proteins in pathogenicNeisseriaceae. FEMS Microbiol Rev 2006; 30:292-319. [PMID: 16472308 DOI: 10.1111/j.1574-6976.2006.00013.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Secreted proteins of pathogenic bacteria are often essential virulence factors. They are involved, for example, in the adherence of the bacteria to host cells or required to suppress the host's defence mechanisms. Until recently, only IgA1 protease had been studied in detail in the NeisseriaceaeNeisseria meningitidis and Neisseria gonorrhoeae. The availability of their genome sequences, however, has boosted research in this area. Here, we present a survey of the secretome of the pathogenic Neisseriaceae, based on the available genome sequences, and the current knowledge of the functions and structures of the secreted proteins. Of the six protein-secretion pathways that are widely disseminated among Gram-negative bacteria, three pathways appear to be present among the Neisseriaceae, i.e. the autotransporter-, the two-partner- and the type I-secretion mechanisms. Comparison of the predicted secretomes reveals a considerable flexibility. As compared with N. meningitidis and the nonpathogen N. lactamica, N. gonorrhoeae appears to have a considerably degenerated secretome, which may reflect its altered niche occupancy. The flexibility of the secretome may be enhanced by the presence of ORFs in the genomes potentially encoding fragments of secreted proteins. We hypothesize that these ORFs may substitute for the corresponding fragments in the full-length genes through genetic recombination, thereby changing the host-cell receptor specificity of the secreted protein.
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Affiliation(s)
- Peter van Ulsen
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Utrecht, The Netherlands
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Tunbridge AJ, Stevanin TM, Lee M, Marriott HM, Moir JWB, Read RC, Dockrell DH. Inhibition of macrophage apoptosis by Neisseria meningitidis requires nitric oxide detoxification mechanisms. Infect Immun 2006; 74:729-33. [PMID: 16369030 PMCID: PMC1346626 DOI: 10.1128/iai.74.1.729-733.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Host-driven macrophage apoptosis contributes to innate immunity during bacterial infection. Neisseria meningitidis inhibits apoptosis in a variety of cells, but its impact on macrophage apoptosis is unknown. We demonstrate that N. meningitidis prevents macrophage apoptosis via genes encoding nitric oxide detoxification and a porin, PorB.
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Affiliation(s)
- Anne J Tunbridge
- Division of Genomic Medicine, F-Floor, University of Sheffield, Beech Hill Road, Sheffield S10 2RX, United Kingdom
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Bergman P, Johansson L, Asp V, Plant L, Gudmundsson GH, Jonsson AB, Agerberth B. Neisseria gonorrhoeae downregulates expression of the human antimicrobial peptide LL-37. Cell Microbiol 2005; 7:1009-17. [PMID: 15953032 DOI: 10.1111/j.1462-5822.2005.00530.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neisseria gonorrhoeae is a human pathogen causing the sexually transmitted disease gonorrhoeae. The bacteria preferentially attach to and invade epithelial cells of the genital tract. As these cells previously have been shown to express the human cathelicidin LL-37, we wanted to investigate the role of LL-37 during N. gonorrhoeae infection. The cervical epithelial cell line ME180 was utilized and the expression of LL-37 was confirmed on both peptide and transcriptional levels. Moreover, LL-37 exhibited potent in vitro activity against N. gonorrhoeae. Interestingly, the transcript and peptide levels of LL-37 were downregulated during infection, according to quantitative real-time polymerase chain reaction (PCR) and immunocyto-chemistry. The downregulation was most prominent with pathogenic strains of Neisseria, while non-pathogenic strains such as Neisseria lactamica and Escherichia coli only exhibited moderate effects. Heat-killed N. gonorrhoeae had no impact on the downregulation, emphasizing the importance of live bacteria. The results in this study suggest that pathogenic Neisseria may gain a survival advantage in the female genital tract by downregulating LL-37 expression.
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Affiliation(s)
- Peter Bergman
- Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, Stockholm, Sweden
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Wooldridge KG, Kizil M, Wells DB, Ala'aldeen DAA. Unusual genetic organization of a functional type I protein secretion system in Neisseria meningitidis. Infect Immun 2005; 73:5554-67. [PMID: 16113272 PMCID: PMC1231126 DOI: 10.1128/iai.73.9.5554-5567.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Proteins secreted by Neisseria meningitidis are thought to play important roles in the pathogenesis of meningococcal disease. These proteins include the iron-repressible repeat-in-toxin (RTX) exoprotein FrpC. Related proteins in other pathogens are secreted via a type I secretion system (TOSS), but such a system has not been demonstrated in N. meningitidis. An in silico search of the group B meningococcal genome suggested the presence of a uniquely organized TOSS. Genes encoding homologs of the Escherichia coli HlyB (ATP-binding), HlyD (membrane fusion), and TolC (outer membrane channel) proteins were identified. In contrast to the cistronic organization of the secretion genes in most other rtx operons, the hlyD and tolC genes were adjacent but unlinked to hlyB; neither locus was part of an operon containing genes encoding putative TOSS substrates. Both loci were flanked by genes normally associated with mobile genetic elements. The three genes were shown to be expressed independently. Mutation at either locus resulted in an inability to secrete FrpC and a related protein, here called FrpC2. Successful complementation of these mutations at an ectopic site confirmed the observed phenotypes were caused by loss of function of the putative TOSS genes. We show that genes scattered in the meningococcal genome encode a functional TOSS required for secretion of the meningococcal RTX proteins.
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Affiliation(s)
- Karl G Wooldridge
- Division of Microbiology and Infectious Diseases, Queens Medical Centre, Nottingham NG7 2UH, United Kingdom.
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Kucknoor A, Mundodi V, Alderete JF. Trichomonas vaginalis adherence mediates differential gene expression in human vaginal epithelial cells. Cell Microbiol 2005; 7:887-97. [PMID: 15888089 PMCID: PMC2562669 DOI: 10.1111/j.1462-5822.2005.00522.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Trichomonas vaginalis, an ancient protist, colonizes the vaginal mucosa causing trichomonosis, a vaginitis that sometimes leads to severe health complications. Preparatory to colonization of the vagina is the adhesion to vaginal epithelial cells (VECs) by trichomonads. We hypothesized that VECs alter the gene expression to form a complex signalling cascade in response to trichomonal adherence. In order to identify the genes that are upregulated, we constructed a subtraction cDNA library after contact with parasites that is enriched for differentially expressed genes from the immortalized MS-74 VECs. Sixty cDNA clones were sequenced and to our knowledge for the first time, differentially regulated genes were identified in response to early trichomonal infection. The identified genes were found to encode functional proteins with specific functions associated with cell structure maintenance and extracellular matrix components, proinflammatory molecules and apoptosis. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) confirmed expression of selected genes. Further, cyclooxygenase 2 (COX-2) protein expression was analysed using Western blot and immunofluorescence assays. Data suggest that p38 mitogen-activated protein (MAP) kinase and tyrosine kinases play a role in COX-2 induction. Finally, T. vaginalis and Tritrichomonas foetus but not Pentatrichomonas hominis induce expression of COX-2. This is a first attempt at elucidating the basis of interaction of trichomonads with host cells and the corresponding host responses triggered by the parasites.
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Affiliation(s)
- Ashwini Kucknoor
- Department of Microbiology and Immunology, University of Texas Health Science Centre at San Antonio, TX, USA
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