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MacAlasdair N, Pesonen M, Brynildsrud O, Eldholm V, Kristiansen PA, Corander J, Caugant DA, Bentley SD. The effect of recombination on the evolution of a population of Neisseria meningitidis. Genome Res 2021; 31:1258-1268. [PMID: 34108268 PMCID: PMC8256868 DOI: 10.1101/gr.264465.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 04/22/2021] [Indexed: 12/02/2022]
Abstract
Neisseria meningitidis (the meningococcus) is a major human pathogen with a history of high invasive disease burden, particularly in sub-Saharan Africa. Our current understanding of the evolution of meningococcal genomes is limited by the rarity of large-scale genomic population studies and lack of in-depth investigation of the genomic events associated with routine pathogen transmission. Here, we fill this knowledge gap by a detailed analysis of 2839 meningococcal genomes obtained through a carriage study of over 50,000 samples collected systematically in Burkina Faso, West Africa, before, during, and after the serogroup A vaccine rollout, 2009-2012. Our findings indicate that the meningococcal genome is highly dynamic, with highly recombinant loci and frequent gene sharing across deeply separated lineages in a structured population. Furthermore, our findings illustrate how population structure can correlate with genome flexibility, as some lineages in Burkina Faso are orders of magnitude more recombinant than others. We also examine the effect of selection on the population, in particular how it is correlated with recombination. We find that recombination principally acts to prevent the accumulation of deleterious mutations, although we do also find an example of recombination acting to speed the adaptation of a gene. In general, we show the importance of recombination in the evolution of a geographically expansive population with deep population structure in a short timescale. This has important consequences for our ability to both foresee the outcomes of vaccination programs and, using surveillance data, predict when lineages of the meningococcus are likely to become a public health concern.
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Affiliation(s)
- Neil MacAlasdair
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Maiju Pesonen
- Oslo Centre for Biostatistics and Epidemiology (OCBE), Oslo University Hospital Research Support Services, Blindern, 0317 Oslo, Norway
| | - Ola Brynildsrud
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
- Department of Food Safety and Infection Biology, Faculty of Veterinary Science, Norwegian University of Life Science, 0454 Oslo, Norway
| | - Vegard Eldholm
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
| | - Paul A Kristiansen
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
| | - Jukka Corander
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
- University of Oslo, Department of Biostatistics, Blindern, 0317 Oslo, Norway
- Helsinki Institute for Information Technology HIIT, Department of Mathematics and Statistics, University of Helsinki, 00014 Helsinki, Finland
| | - Dominique A Caugant
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
- Department of Community Medicine, Faculty of Medicine, University of Oslo, Blindern, 0316 Oslo, Norway
| | - Stephen D Bentley
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
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Wörmann ME, Horien CL, Johnson E, Liu G, Aho E, Tang CM, Exley RM. Neisseria cinerea isolates can adhere to human epithelial cells by type IV pilus-independent mechanisms. MICROBIOLOGY-SGM 2016; 162:487-502. [PMID: 26813911 DOI: 10.1099/mic.0.000248] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In pathogenic Neisseria species the type IV pili (Tfp) are of primary importance in host-pathogen interactions. Tfp mediate initial bacterial attachment to cell surfaces and formation of microcolonies via pilus-pilus interactions. Based on genome analysis, many non-pathogenic Neisseria species are predicted to express Tfp, but aside from studies on Neisseria elongata, relatively little is known about the formation and function of pili in these organisms. Here, we have analysed pilin expression and the role of Tfp in Neisseria cinerea. This non-pathogenic species shares a close taxonomic relationship to the pathogen Neisseria meningitidis and also colonizes the human oropharyngeal cavity. Through analysis of non-pathogenic Neisseria genomes we identified two genes with homology to pilE, which encodes the major pilin of N. meningitidis. We show which of the two genes is required for Tfp expression in N. cinerea and that Tfp in this species are required for DNA competence, similar to other Neisseria. However, in contrast to the meningococcus, deletion of the pilin gene did not impact the association of N. cinerea to human epithelial cells, demonstrating that N. cinerea isolates can adhere to human epithelial cells by Tfp-independent mechanisms.
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Affiliation(s)
- Mirka E Wörmann
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Corey L Horien
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Errin Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Guangyu Liu
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Ellen Aho
- Department of Biology, Concordia College, Moorhead, MN, USA
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Rachel M Exley
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
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Wörmann ME, Horien CL, Bennett JS, Jolley KA, Maiden MCJ, Tang CM, Aho EL, Exley RM. Sequence, distribution and chromosomal context of class I and class II pilin genes of Neisseria meningitidis identified in whole genome sequences. BMC Genomics 2014; 15:253. [PMID: 24690385 PMCID: PMC4023411 DOI: 10.1186/1471-2164-15-253] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 03/25/2014] [Indexed: 12/05/2022] Open
Abstract
Background Neisseria meningitidis expresses type four pili (Tfp) which are important for colonisation and virulence. Tfp have been considered as one of the most variable structures on the bacterial surface due to high frequency gene conversion, resulting in amino acid sequence variation of the major pilin subunit (PilE). Meningococci express either a class I or a class II pilE gene and recent work has indicated that class II pilins do not undergo antigenic variation, as class II pilE genes encode conserved pilin subunits. The purpose of this work was to use whole genome sequences to further investigate the frequency and variability of the class II pilE genes in meningococcal isolate collections. Results We analysed over 600 publically available whole genome sequences of N. meningitidis isolates to determine the sequence and genomic organization of pilE. We confirmed that meningococcal strains belonging to a limited number of clonal complexes (ccs, namely cc1, cc5, cc8, cc11 and cc174) harbour a class II pilE gene which is conserved in terms of sequence and chromosomal context. We also identified pilS cassettes in all isolates with class II pilE, however, our analysis indicates that these do not serve as donor sequences for pilE/pilS recombination. Furthermore, our work reveals that the class II pilE locus lacks the DNA sequence motifs that enable (G4) or enhance (Sma/Cla repeat) pilin antigenic variation. Finally, through analysis of pilin genes in commensal Neisseria species we found that meningococcal class II pilE genes are closely related to pilE from Neisseria lactamica and Neisseria polysaccharea, suggesting horizontal transfer among these species. Conclusions Class II pilins can be defined by their amino acid sequence and genomic context and are present in meningococcal isolates which have persisted and spread globally. The absence of G4 and Sma/Cla sequences adjacent to the class II pilE genes is consistent with the lack of pilin subunit variation in these isolates, although horizontal transfer may generate class II pilin diversity. This study supports the suggestion that high frequency antigenic variation of pilin is not universal in pathogenic Neisseria.
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Affiliation(s)
| | | | | | | | | | | | - Ellen L Aho
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
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Abstract
Type IV pili (T4P) are multifunctional protein fibers produced on the surfaces of a wide variety of bacteria and archaea. The major subunit of T4P is the type IV pilin, and structurally related proteins are found as components of the type II secretion (T2S) system, where they are called pseudopilins; of DNA uptake/competence systems in both Gram-negative and Gram-positive species; and of flagella, pili, and sugar-binding systems in the archaea. This broad distribution of a single protein family implies both a common evolutionary origin and a highly adaptable functional plan. The type IV pilin is a remarkably versatile architectural module that has been adopted widely for a variety of functions, including motility, attachment to chemically diverse surfaces, electrical conductance, acquisition of DNA, and secretion of a broad range of structurally distinct protein substrates. In this review, we consider recent advances in this research area, from structural revelations to insights into diversity, posttranslational modifications, regulation, and function.
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Hung MC, Christodoulides M. The biology of Neisseria adhesins. BIOLOGY 2013; 2:1054-109. [PMID: 24833056 PMCID: PMC3960869 DOI: 10.3390/biology2031054] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 01/15/2023]
Abstract
Members of the genus Neisseria include pathogens causing important human diseases such as meningitis, septicaemia, gonorrhoea and pelvic inflammatory disease syndrome. Neisseriae are found on the exposed epithelia of the upper respiratory tract and the urogenital tract. Colonisation of these exposed epithelia is dependent on a repertoire of diverse bacterial molecules, extending not only from the surface of the bacteria but also found within the outer membrane. During invasive disease, pathogenic Neisseriae also interact with immune effector cells, vascular endothelia and the meninges. Neisseria adhesion involves the interplay of these multiple surface factors and in this review we discuss the structure and function of these important molecules and the nature of the host cell receptors and mechanisms involved in their recognition. We also describe the current status for recently identified Neisseria adhesins. Understanding the biology of Neisseria adhesins has an impact not only on the development of new vaccines but also in revealing fundamental knowledge about human biology.
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Affiliation(s)
- Miao-Chiu Hung
- Neisseria Research, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD, UK.
| | - Myron Christodoulides
- Neisseria Research, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD, UK.
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Higashi DL, Biais N, Weyand NJ, Agellon A, Sisko JL, Brown LM, So M. N. elongata produces type IV pili that mediate interspecies gene transfer with N. gonorrhoeae. PLoS One 2011; 6:e21373. [PMID: 21731720 PMCID: PMC3120873 DOI: 10.1371/journal.pone.0021373] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 05/26/2011] [Indexed: 02/01/2023] Open
Abstract
The genus Neisseria contains at least eight commensal and two pathogenic species. According to the Neisseria phylogenetic tree, commensals are basal to the pathogens. N. elongata, which is at the opposite end of the tree from N. gonorrhoeae, has been observed to be fimbriated, and these fimbriae are correlated with genetic competence in this organism. We tested the hypothesis that the fimbriae of N. elongata are Type IV pili (Tfp), and that Tfp functions in genetic competence. We provide evidence that the N. elongata fimbriae are indeed Tfp. Tfp, as well as the DNA Uptake Sequence (DUS), greatly enhance N. elongata DNA transformation. Tfp allows N. elongata to make intimate contact with N. gonorrhoeae and to mediate the transfer of antibiotic resistance markers between these two species. We conclude that Tfp functional for genetic competence is a trait of a commensal member of the Neisseria genus. Our findings provide a mechanism for the horizontal gene transfer that has been observed among Neisseria species.
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MESH Headings
- Base Sequence
- DNA, Bacterial/metabolism
- Drug Resistance, Bacterial/drug effects
- Epithelial Cells/drug effects
- Epithelial Cells/microbiology
- Epithelial Cells/ultrastructure
- Fimbriae, Bacterial/drug effects
- Fimbriae, Bacterial/genetics
- Fimbriae, Bacterial/metabolism
- Fimbriae, Bacterial/ultrastructure
- Gene Transfer, Horizontal/genetics
- Genes, Bacterial/genetics
- Humans
- Mutation/genetics
- Neisseria elongata/drug effects
- Neisseria elongata/genetics
- Neisseria elongata/metabolism
- Neisseria elongata/ultrastructure
- Neisseria gonorrhoeae/drug effects
- Neisseria gonorrhoeae/genetics
- Neisseria gonorrhoeae/ultrastructure
- Rifampin/pharmacology
- Species Specificity
- Surface Properties/drug effects
- Transcription, Genetic/drug effects
- Transformation, Bacterial/drug effects
- Transformation, Bacterial/genetics
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Affiliation(s)
- Dustin L. Higashi
- Department of Immunobiology and the BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Nicolas Biais
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Nathan J. Weyand
- Department of Immunobiology and the BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Al Agellon
- University Spectroscopy and Imaging Facilities, University of Arizona, Tucson, Arizona, United States of America
| | - Jennifer L. Sisko
- Department of Immunobiology and the BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
| | - Lewis M. Brown
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Magdalene So
- Department of Immunobiology and the BIO5 Institute, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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Luke-Marshall NR, Sauberan SL, Campagnari AA. Comparative analyses of the Moraxella catarrhalis type-IV pilus structural subunit PilA. Gene 2011; 477:19-23. [PMID: 21256201 DOI: 10.1016/j.gene.2011.01.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 01/05/2011] [Accepted: 01/11/2011] [Indexed: 10/18/2022]
Abstract
Moraxella catarrhalis is a Gram-negative aerobic diplococcus that is a mucosal pathogen of the upper and lower respiratory tracts in humans. In order to colonize the human host and establish an infection, M. catarrhalis must be able to effectively attach to the respiratory mucosal epithelia. Although little is known about M. catarrhalis pathogenesis, our laboratory has previously shown that expression of type IV pili (TFP) contributes to mucosal colonization. TFP are filamentous surface appendages primarily composed of a single protein subunit termed pilin, which is encoded by pilA in M. catarrhalis. These surface structures play a crucial role in the initiation of disease by a wide range of pathogenic bacteria. Our studies also indicate that unlike the pilin of the pathogenic Neisseria species, which exhibit both phase and antigenic variation, the pilin subunit of M. catarrhalis appears to be more highly conserved as there are no major pilin variants produced by a single strain and only two major PilA antigenic variants, termed clade 1 and clade 2, have been observed between strains. Moreover, we have determined that these highly conserved bacterial surface structures are expressed by all M. catarrhalis clinical isolates evaluated. Therapeutic or vaccine-based interventions that prevent or diminish nasopharyngeal colonization will likely decrease acute and recurrent M. catarrhalis infections in prone populations. Thus, our data indicate that additional studies aimed at elucidating the role of PilA in the pathogenesis and host response to M. catarrhalis infections are warranted.
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Affiliation(s)
- Nicole R Luke-Marshall
- Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, NY 14214, USA
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8
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Cahoon LA, Stohl EA, Seifert HS. The Neisseria gonorrhoeae photolyase orthologue phrB is required for proper DNA supercoiling but does not function in photo-reactivation. Mol Microbiol 2010; 79:729-42. [PMID: 21255115 DOI: 10.1111/j.1365-2958.2010.07481.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neisseria gonorrhoeae (Gc) is an obligate human pathogen and the causative agent of the sexually transmitted infection, gonorrhoea. Despite the fact that the gonococcus is not normally exposed to UV irradiation or visible light, the bacterium expresses a phrB orthologue, which in other organisms encodes a DNA photolyase that repairs UV-induced pyrimidine dimers with energy provided by visible light. We show that a Gc phrB mutant is not more sensitive to UV irradiation, independent of visible light exposure, and that the Gc phrB cannot complement an Escherichia coli phrB mutant strain. The Gc phrB mutant had a reduced colony size that was not a result of a growth defect and the mutant cells exhibited an altered morphology. Although the phrB mutant exhibited increased sensitivity to oxidative killing; it showed increased survival on media containing nalidixic acid or rifampicin, but did not have an increased mutation rate to these antibiotics or spectinomycin and kasugamycin. The Gc phrB mutant showed increased negative DNA supercoiling, but while the protein bound double-stranded DNA, it did not express topoisomerase activity. We conclude that the Gc PhrB has a previously unrecognized role in maintaining DNA supercoiling that is important for normal cell physiology.
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Affiliation(s)
- Laty A Cahoon
- Northwestern University, Feinberg School of Medicine, Department of Microbiology-Immunology, 303 E. Chicago Ave., Chicago, IL 60611, USA
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9
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Harrison OB, Maiden MCJ, Rokbi B. Distribution of transferrin binding protein B gene (tbpB) variants among Neisseria species. BMC Microbiol 2008; 8:66. [PMID: 18430216 PMCID: PMC2386816 DOI: 10.1186/1471-2180-8-66] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 04/22/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Transferrin binding protein B (tbpB), an outer membrane lipoprotein, is required for the acquisition of iron from human transferrin. Two tbpB families have been documented in Neisseria meningitidis: an isotype I tbpB gene of 1.8 kb and an isotype II tbpB gene of 2.1 kb, the former expressed by meningococci in the disease-associated ST-11 clonal complex and the latter found among meningococci belonging to the hyper-invasive clonal complexes including ST-8, ST-18, ST-32, ST-41/44 as well as N. gonorrhoeae isolates. The origin of the isotype I tbpB gene is unknown, however several features in common with non-pathogenic Neisseria and the ST-11 clonal complex N. meningitidis isolate FAM18 have been documented leading to the hypothesis that the isotype I tbpB gene may also be shared between non-pathogenic Neisseria and ST-11 meningococci. As a result, the diversity of the tbpB gene was investigated in a defined collection of Neisseria species. RESULTS Two families of isotype I tbpB were identified: family A containing conserved genes belonging to ST-11 meningococci, N. polysaccharea and N. lactamica isolates and family B including more diverse isotype I tbpB genes from N. sicca, N. mucosa, N. flava, N. subflava as well as N. cinerea, N. flavescens and N. polysaccharea isolates. Three isotype II tbpB families were identified with: family C containing diverse tbpB genes belonging to N. polysaccharea, N. lactamica, N. gonorrhoeae and N. meningitidis isolates, family D including another subset of isotype II tbpB genes from N. lactamica isolates and family E solely composed of N. gonorrhoeae tbpB genes. CONCLUSION This study reveals another instance of similarity between meningococci of the ST-11 clonal complex and non-pathogenic Neisseria with the origin of the isotype I tbpB gene resulting from a horizontal genetic transfer event occurring between these two populations.
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Affiliation(s)
- Odile B Harrison
- The Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3SY, UK.
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10
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Bentley SD, Vernikos GS, Snyder LAS, Churcher C, Arrowsmith C, Chillingworth T, Cronin A, Davis PH, Holroyd NE, Jagels K, Maddison M, Moule S, Rabbinowitsch E, Sharp S, Unwin L, Whitehead S, Quail MA, Achtman M, Barrell B, Saunders NJ, Parkhill J. Meningococcal genetic variation mechanisms viewed through comparative analysis of serogroup C strain FAM18. PLoS Genet 2006; 3:e23. [PMID: 17305430 PMCID: PMC1797815 DOI: 10.1371/journal.pgen.0030023] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 12/21/2006] [Indexed: 11/19/2022] Open
Abstract
The bacterium Neisseria meningitidis is commonly found harmlessly colonising the mucosal surfaces of the human nasopharynx. Occasionally strains can invade host tissues causing septicaemia and meningitis, making the bacterium a major cause of morbidity and mortality in both the developed and developing world. The species is known to be diverse in many ways, as a product of its natural transformability and of a range of recombination and mutation-based systems. Previous work on pathogenic Neisseria has identified several mechanisms for the generation of diversity of surface structures, including phase variation based on slippage-like mechanisms and sequence conversion of expressed genes using information from silent loci. Comparison of the genome sequences of two N. meningitidis strains, serogroup B MC58 and serogroup A Z2491, suggested further mechanisms of variation, including C-terminal exchange in specific genes and enhanced localised recombination and variation related to repeat arrays. We have sequenced the genome of N. meningitidis strain FAM18, a representative of the ST-11/ET-37 complex, providing the first genome sequence for the disease-causing serogroup C meningococci; it has 1,976 predicted genes, of which 60 do not have orthologues in the previously sequenced serogroup A or B strains. Through genome comparison with Z2491 and MC58 we have further characterised specific mechanisms of genetic variation in N. meningitidis, describing specialised loci for generation of cell surface protein variants and measuring the association between noncoding repeat arrays and sequence variation in flanking genes. Here we provide a detailed view of novel genetic diversification mechanisms in N. meningitidis. Our analysis provides evidence for the hypothesis that the noncoding repeat arrays in neisserial genomes (neisserial intergenic mosaic elements) provide a crucial mechanism for the generation of surface antigen variants. Such variation will have an impact on the interaction with the host tissues, and understanding these mechanisms is important to aid our understanding of the intimate and complex relationship between the human nasopharynx and the meningococcus. Human surface tissues, including the skin and gut lining, are host to many different species of bacteria. N. meningitidis is a species of bacteria that is only found in humans where it is able to colonise mucosal surfaces of the nasopharynx (nose and throat). This association is normally harmless and at any one time around 15% of the population are carriers. Some strains of N. meningitidis can cause disease by invading the host tissue leading to septicaemia or meningitis. We aim to gain understanding of the mechanisms by which these bacteria cause disease by studying and comparing genomes from different strains. Here we describe specific genes and associated repetitive DNA sequences that are involved in variation of the bacterial cell surface. The repeat sequences encourage the swapping of genes that code for variant copies of cell surface proteins. The resulting variation of the bacterial cell surface appears to be important in the close interaction between host and bacteria and the potential for disease.
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11
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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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