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Kuiper JWP, Gregg HL, Schüber M, Klein J, Hauck CR. Controling the cytoskeleton during CEACAM3-mediated phagocytosis. Eur J Cell Biol 2024; 103:151384. [PMID: 38215579 DOI: 10.1016/j.ejcb.2024.151384] [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: 09/01/2023] [Revised: 11/20/2023] [Accepted: 01/03/2024] [Indexed: 01/14/2024] Open
Abstract
Phagocytosis, an innate defense mechanism of multicellular animals, is initiated by specialized surface receptors. A phagocytic receptor expressed by human polymorphonuclear granulocytes, the major professional phagocytes in our body, is one of the fastest evolving human proteins implying a special role in human biology. This receptor, CEACAM3, is a member of the CarcinoEmbryonic Antigen-related Cell Adhesion Molecule (CEACAM) family and dedicated to the immediate recognition and rapid internalization of human-restricted pathogens. In this focused contribution, we will review the special adaptations of this protein, which co-evolves with different species of mucosa-colonizing bacteria. While the extracellular Immunoglobulin-variable (IgV)-like domain recognizes various bacterial adhesins, an Immunoreceptor Tyrosine-based Activation Motif (ITAM)-like sequence in the cytoplasmic tail of CEACAM3 constitutes the central signaling hub to trigger actin rearrangements needed for efficient phagocytosis. A major emphasis of this review will be placed on recent findings, which have revealed the multi-level control of this powerful phagocytic device. As tyrosine phosphorylation and small GTPase activity are central for CEACAM3-mediated phagocytosis, the counterregulation of CEACAM3 activity involves the receptor-type protein tyrosine phosphatase J (PTPRJ) as well as the Rac-GTP scavenging protein Cyri-B. Interference with such negative regulatory circuits has revealed that CEACAM3-mediated phagocytosis can be strongly enhanced. In principle, the knowledge gained by studying CEACAM3 can be applied to other phagocytic systems and opens the door to treatments, which boost the phagocytic capacity of professional phagocytes.
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Affiliation(s)
| | - Helena L Gregg
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Germany
| | - Meike Schüber
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Germany
| | - Jule Klein
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Germany
| | - Christof R Hauck
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Germany; Konstanz Research School Chemical Biology, Universität Konstanz, Germany.
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2
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Shikov AE, Savina IA, Nizhnikov AA, Antonets KS. Recombination in Bacterial Genomes: Evolutionary Trends. Toxins (Basel) 2023; 15:568. [PMID: 37755994 PMCID: PMC10534446 DOI: 10.3390/toxins15090568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/02/2023] [Accepted: 09/07/2023] [Indexed: 09/28/2023] Open
Abstract
Bacterial organisms have undergone homologous recombination (HR) and horizontal gene transfer (HGT) multiple times during their history. These processes could increase fitness to new environments, cause specialization, the emergence of new species, and changes in virulence. Therefore, comprehensive knowledge of the impact and intensity of genetic exchanges and the location of recombination hotspots on the genome is necessary for understanding the dynamics of adaptation to various conditions. To this end, we aimed to characterize the functional impact and genomic context of computationally detected recombination events by analyzing genomic studies of any bacterial species, for which events have been detected in the last 30 years. Genomic loci where the transfer of DNA was detected pertained to mobile genetic elements (MGEs) housing genes that code for proteins engaged in distinct cellular processes, such as secretion systems, toxins, infection effectors, biosynthesis enzymes, etc. We found that all inferences fall into three main lifestyle categories, namely, ecological diversification, pathogenesis, and symbiosis. The latter primarily exhibits ancestral events, thus, possibly indicating that adaptation appears to be governed by similar recombination-dependent mechanisms.
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Affiliation(s)
- Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (I.A.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Iuliia A. Savina
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (I.A.S.); (A.A.N.)
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (I.A.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (A.E.S.); (I.A.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University (SPbSU), 199034 St. Petersburg, Russia
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3
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FHUSPA2/10 is a bactericidal monoclonal antibody targeting multiple repeated sequences of Moraxella catarrhalis UspA2. Vaccine 2022; 40:6520-6527. [PMID: 36202640 DOI: 10.1016/j.vaccine.2022.09.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 12/05/2022]
Abstract
Moraxella catarrhalis is an important and common respiratory pathogen that can cause Otitis Media, Community Acquired Pneumonia, and has been associated with an increased risk of exacerbations in chronic obstructive pulmonary disease in adults, leading to morbidity and mortality. Its ubiquitous surface protein A2 (UspA2) has been shown to interact with host structures and extracellular matrix proteins, suggesting a role at an early stage of infection and a contribution to bacterial serum resistance. The UspA proteins are homo-trimeric autotransporters that appear as a lollipop-shaped structure in electron micrographs. They are composed of an N-terminal head with adhesive properties, followed by a stalk, which ends by an amphipathic helix and a C-terminal membrane domain. The three family members UspA1, UspA2 and UspA2H, present different amino acid signatures both at the head and membrane-spanning regions. By combining electron microscopy, hydrogen deuterium exchange mass spectrometry and protein modeling, we identified a shared and repeated epitope recognized by FHUSPA2/10, a potent cross-bactericidal monoclonal antibody raised by UspA2 and deduced key amino acids involved in the binding. The finding strengthens the potential of UspA2 to be incorporated in a vaccine formulation against M. catarrhalis.
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4
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Ysebaert C, Castado C, Mortier MC, Rioux S, Feron C, Di Paolo E, Weynants V, Blais N, Devos N, Hermand P. UspA2 is a cross-protective Moraxella catarrhalis vaccine antigen. Vaccine 2021; 39:5641-5649. [PMID: 34446318 DOI: 10.1016/j.vaccine.2021.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 11/29/2022]
Abstract
Moraxella catarrhalis (Mcat) is a key pathogen associated with exacerbations of chronic obstructive pulmonary disease (COPD) in adults and playing a significant role in otitis media in children. A vaccine would help to reduce the morbidity and mortality associated with these diseases. UspA2 is an Mcat surface antigen considered earlier as vaccine candidate before the interest in this molecule vanished due to sequence variability. However, the observation that some conserved domains are the target of bactericidal antibodies prompted us to reconsider UspA2 as a potential vaccine antigen. We first determined its prevalence among the COPD patients from the AERIS study, as the prevalence of UspA2 in a COPD-restricted population had yet to be documented. The gene was found in all Mcat isolates either as UspA2 or UspA2H variant. The percentage of UspA2H variant was higher than in any report so far, reaching 51%. A potential link between the role of UspA2H in biofilm formation and this high prevalence is discussed. To study further UspA2 as a vaccine antigen, recombinant UspA2 molecules were designed and used in animal models and bactericidal assays. We showed that UspA2 is immunogenic and that UspA2 immunization clears Mcat pulmonary challenge in a mouse model. In a serum bactericidal assay, anti-UspA2 antibodies generated in mice, guinea pigs or rabbits were able to kill Mcat strains of various origins, including a subset of isolates from the AERIS study, cross-reacting with UspA2H and even UspA1, a closely related Mcat surface protein. In conclusion, UspA2 is a cross-reactive Mcat antigen presenting the characteristics of a vaccine candidate.
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5
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Shhadeh A, Galaski J, Alon-Maimon T, Fahoum J, Wiener R, Slade DJ, Mandelboim O, Bachrach G. CEACAM1 Activation by CbpF-Expressing E. coli. Front Cell Infect Microbiol 2021; 11:699015. [PMID: 34395310 PMCID: PMC8358318 DOI: 10.3389/fcimb.2021.699015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/13/2021] [Indexed: 01/04/2023] Open
Abstract
Recent studies on the oral, anaerobic, gram-negative bacterium Fusobacterium nucleatum revealed its presence and involvement in colorectal, esophageal and breast cancer. We previously demonstrated that F. nucleatum binds and activates the human inhibitory receptors TIGIT and CEACAM1 leading to inhibition of T and NK cell anti-tumor immunity. CEACAM1 was found to be bound and activated by the fusobacterial trimeric autotransporter adhesin CbpF. Here we report the generation of a recombinant E. coli expressing full-length CbpF that efficiently binds and activates CEACAM1.
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Affiliation(s)
- Amjad Shhadeh
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel
| | - Johanna Galaski
- The Concern Foundation Laboratories at the Lautenberg Center for General and Tumor Immunology, Department of Immunology and Cancer Research, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, The Hebrew University Medical School, Jerusalem, Israel.,I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tamar Alon-Maimon
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel
| | - Jamal Fahoum
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, The Hebrew University Medical School, Jerusalem, Israel
| | - Reuven Wiener
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, The Hebrew University Medical School, Jerusalem, Israel
| | - Daniel J Slade
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Ofer Mandelboim
- The Concern Foundation Laboratories at the Lautenberg Center for General and Tumor Immunology, Department of Immunology and Cancer Research, Institute for Medical Research Israel Canada (IMRIC), Faculty of Medicine, The Hebrew University Medical School, Jerusalem, Israel
| | - Gilad Bachrach
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel
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6
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Kowalewski J, Paris T, Gonzalez C, Lelièvre E, Castaño Valencia L, Boutrois M, Augier C, Lutfalla G, Yatime L. Characterization of a member of the CEACAM protein family as a novel marker of proton pump-rich ionocytes on the zebrafish epidermis. PLoS One 2021; 16:e0254533. [PMID: 34252160 PMCID: PMC8274849 DOI: 10.1371/journal.pone.0254533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/29/2021] [Indexed: 01/04/2023] Open
Abstract
In humans, several members of the CEACAM receptor family have been shown to interact with intestinal pathogens in an inflammatory context. While CEACAMs have long been thought to be only present in mammals, recent studies have identified ceacam genes in other vertebrates, including teleosts. The function of these related genes remains however largely unknown. To gain insight into the function of CEACAM proteins in fish, we undertook the study of a putative member of the family, CEACAMz1, identified in Danio rerio. Sequence analysis of the ceacamz1 gene product predicted a GPI-anchored extracellular protein containing eleven immunoglobulin domains but revealed no evident orthology with human CEACAMs. Using a combination of RT-PCR analyses and in situ hybridization experiments, as well as a fluorescent reporter line, we showed that CEACAMz1 is first expressed in discrete cells on the ventral skin of zebrafish larvae and later on in the developing gills. This distribution remains constant until juvenile stage is reached, at which point CEACAMz1 is almost exclusively expressed in gills. We further observed that at late larval stages, CEACAMz1-expressing cells mostly localize on the afferent side of the branchial filaments and possibly in the inter-lamellar space. Using immunolabelling and 3D-reconstructions, we showed that CEACAMz1 is expressed in cells from the uppermost layer of skin epidermis. These cells are embedded within the keratinocytes pavement and we unambiguously identified them as proton-pump rich ionocytes (HR cells). As the expression of ceacamz1 is turned on concomitantly to that of other known markers of HR cells, we propose that ceacamz1 may serve as a novel marker of mature HR cells from the zebrafish epidermis.
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Affiliation(s)
- Julien Kowalewski
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Théo Paris
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Catherine Gonzalez
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Etienne Lelièvre
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Lina Castaño Valencia
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Morgan Boutrois
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Camille Augier
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Georges Lutfalla
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Laure Yatime
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, University of Montpellier, CNRS, INSERM, Montpellier, France
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7
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Microscale communication between bacterial pathogens and the host epithelium. Genes Immun 2021; 22:247-254. [PMID: 34588625 PMCID: PMC8497271 DOI: 10.1038/s41435-021-00149-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/18/2021] [Accepted: 08/23/2021] [Indexed: 02/01/2023]
Abstract
Pathogenic bacteria have evolved a variety of highly selective adhesins allowing these microbes to engage specific surface determinants of their eukaryotic host cells. Receptor clustering induced by the multivalent microorganisms will not only anchor the bacteria to the tissue, but will inevitably trigger host cell signaling. It has become clear, that these bacteria-initiated signaling events can be seen as a form of localized communication with host epithelial cells. Such a microscale communication can have immediate consequences in the form of changes in host cell membrane morphology or cytoskeletal organization, but can also lead to transcriptional responses and medium- and long-term alterations in cellular physiology. In this review, we will discuss several examples of this form of microscale communication between bacterial pathogens and mammalian host cells and try to delineate their downstream ramifications in the infection process. Furthermore, we will highlight recent findings that specialized pathogenic bacteria utilize the adhesin-based interaction to diffuse the short-range messenger molecule nitric oxide into the host tissue. While anti-adhesive strategies to disrupt the initial bacterial attachment have not yet translated into medical applications, the ability to interfere with the microscale communication emanating on the host side provides an unconventional approach for preventing infectious diseases.
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8
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Moraxella catarrhalis phase-variable loci show differences in expression during conditions relevant to disease. PLoS One 2020; 15:e0234306. [PMID: 32555615 PMCID: PMC7302503 DOI: 10.1371/journal.pone.0234306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 05/22/2020] [Indexed: 11/29/2022] Open
Abstract
Moraxella catarrhalis is a human-adapted, opportunistic bacterial pathogen of the respiratory mucosa. Although asymptomatic colonization of the nasopharynx is common, M. catarrhalis can ascend into the middle ear, where it is a prevalent causative agent of otitis media in children, or enter the lower respiratory tract, where it is associated with acute exacerbations of chronic obstructive pulmonary disease in adults. Phase variation is the high frequency, random, reversible switching of gene expression that allows bacteria to adapt to different host microenvironments and evade host defences, and is most commonly mediated by simple DNA sequence repeats. Bioinformatic analysis of five closed M. catarrhalis genomes identified 17 unique simple DNA sequence repeat tracts that were variable between strains, indicating the potential to mediate phase variable expression of the associated genes. Assays designed to assess simple sequence repeat variation under conditions mimicking host infection demonstrated that phase variation of uspA1 (ubiquitous surface protein A1) from high to low expression occurs over 72 hours of biofilm passage, while phase variation of uspA2 (ubiquitous surface protein A2) to high expression variants occurs during repeated exposure to human serum, as measured by mRNA levels. We also identify and confirm the variable expression of two novel phase variable genes encoding a Type III DNA methyltransferase (modO), and a conserved hypothetical permease (MC25239_RS00020). These data reveal the repertoire of phase variable genes mediated by simple sequence repeats in M. catarrhalis and demonstrate that modulation of expression under conditions mimicking human infection is attributed to changes in simple sequence repeat length.
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Thibau A, Dichter AA, Vaca DJ, Linke D, Goldman A, Kempf VAJ. Immunogenicity of trimeric autotransporter adhesins and their potential as vaccine targets. Med Microbiol Immunol 2020; 209:243-263. [PMID: 31788746 PMCID: PMC7247748 DOI: 10.1007/s00430-019-00649-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/19/2019] [Indexed: 12/15/2022]
Abstract
The current problem of increasing antibiotic resistance and the resurgence of numerous infections indicate the need for novel vaccination strategies more than ever. In vaccine development, the search for and the selection of adequate vaccine antigens is the first important step. In recent years, bacterial outer membrane proteins have become of major interest, as they are the main proteins interacting with the extracellular environment. Trimeric autotransporter adhesins (TAAs) are important virulence factors in many Gram-negative bacteria, are localised on the bacterial surface, and mediate the first adherence to host cells in the course of infection. One example is the Neisseria adhesin A (NadA), which is currently used as a subunit in a licensed vaccine against Neisseria meningitidis. Other TAAs that seem promising vaccine candidates are the Acinetobacter trimeric autotransporter (Ata), the Haemophilus influenzae adhesin (Hia), and TAAs of the genus Bartonella. Here, we review the suitability of various TAAs as vaccine candidates.
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Affiliation(s)
- Arno Thibau
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe-University, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Alexander A. Dichter
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe-University, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Diana J. Vaca
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe-University, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
| | - Dirk Linke
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Adrian Goldman
- Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, Leeds, UK
- Molecular and Integrative Biosciences Program, University of Helsinki, Helsinki, Finland
| | - Volkhard A. J. Kempf
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe-University, Paul-Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
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Brewer ML, Dymock D, Brady RL, Singer BB, Virji M, Hill DJ. Fusobacterium spp. target human CEACAM1 via the trimeric autotransporter adhesin CbpF. J Oral Microbiol 2019; 11:1565043. [PMID: 30719234 PMCID: PMC6346709 DOI: 10.1080/20002297.2018.1565043] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/24/2018] [Accepted: 12/28/2018] [Indexed: 12/20/2022] Open
Abstract
Neisseria meningitidis, Haemophilus influenzae, and Moraxella catarrhalis are pathogenic bacteria adapted to reside on human respiratory mucosal epithelia. One common feature of these species is their ability to target members of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family, especially CEACAM1, which is achieved via structurally distinct ligands expressed by each species. Beside respiratory epithelial cells, cells at the dentogingival junction express high levels of CEACAM1. It is possible that bacterial species resident within the oral cavity also utilise CEACAM1 for colonisation and invasion of gingival tissues. From a screen of 59 isolates from the human oral cavity representing 49 bacterial species, we identified strains from Fusobacterium bound to CEACAM1. Of the Fusobacterium species tested, the CEACAM1-binding property was exhibited by F. nucleatum (Fn) and F. vincentii (Fv) but not F. polymorphum (Fp) or F. animalis (Fa) strains tested. These studies identified that CEACAM adhesion was mediated using a trimeric autotransporter adhesin (TAA) for which no function has thus far been defined. We therefore propose the name CEACAM binding protein of Fusobacterium (CbpF). CbpF was identified to be present in the majority of unspeciated Fusobacterium isolates confirming a subset of Fusobacterium spp. are able to target human CEACAM1.
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Affiliation(s)
| | - David Dymock
- School of Oral and Dental Sciences, University of Bristol, UK
| | - R Leo Brady
- School of Biochemistry, University of Bristol, UK
| | | | - Mumtaz Virji
- School of Cellular & Molecular Medicine, University of Bristol, UK
| | - Darryl J Hill
- School of Cellular & Molecular Medicine, University of Bristol, UK
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11
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García-Gil A, Lopez-Bailon LU, Ortiz-Navarrete V. Beyond the antibody: B cells as a target for bacterial infection. J Leukoc Biol 2019; 105:905-913. [PMID: 30657607 DOI: 10.1002/jlb.mr0618-225r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/15/2018] [Accepted: 12/26/2018] [Indexed: 12/16/2022] Open
Abstract
It is well established that B cells play an important role during infections beyond antibody production. B cells produce cytokines and are APCs for T cells. Recently, it has become clear that several pathogenic bacterial genera, such as Salmonella, Brucella, Mycobacterium, Listeria, Francisella, Moraxella, and Helicobacter, have evolved mechanisms such as micropinocytosis induction, inflammasome down-regulation, inhibitory molecule expression, apoptosis induction, and anti-inflammatory cytokine secretion to manipulate B cell functions influencing immune responses. In this review, we summarize our current understanding of B cells as targets of bacterial infection and the mechanisms by which B cells become a niche for bacterial survival and replication away from extracellular immune responses such as complement and antibodies.
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Affiliation(s)
- Abraham García-Gil
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Luis Uriel Lopez-Bailon
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Vianney Ortiz-Navarrete
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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12
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Utilization of Variant and Fusion Proteins To Functionally Map the Aggregatibacter actinomycetemcomitans Trimeric Autotransporter Protein ApiA. Infect Immun 2018; 86:IAI.00697-17. [PMID: 29229732 DOI: 10.1128/iai.00697-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/01/2017] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative bacterium Aggregatibacter actinomycetemcomitans is a causative agent of localized aggressive periodontitis. Critical to its infection process is the first and essential step of attachment, which is related to the coordinated functions of surface components comprised of proteins and extracellular polysaccharides. One such protein is the outer membrane trimeric autotransporter protein ApiA, a versatile virulence factor with numerous functions, including cell binding, invasion, serum resistance, autoaggregation, and induction of cytokine release. Here we report on the use of Escherichia coli strains expressing protein variants to define the separate functions ascribed to the N terminus and those related to the C terminus. Importantly, a hybrid protein that comprised the N terminus of trimeric ApiA and the β-barrel domain of monomeric autotransporter Aae was constructed, which allowed the expression of a monomer surface-exposed domain of ApiA. Functional and phenotypic analyses demonstrated that the C terminus of ApiA forms an independent domain that is crucial for general stability and trimer formation, which appears to be associated with autoaggregation, biofilm formation, and surface expression. Importantly, the results show that the monomeric form of the N-terminal passenger domain of ApiA, while surface exposed, is sufficient for binding to buccal epithelial cells; however, it is not sufficient to allow aggregation and biofilm formation, strengthening the importance of the role of trimerization in these phenotypes.
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13
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Blakeway LV, Tan A, Peak IRA, Seib KL. Virulence determinants of Moraxella catarrhalis: distribution and considerations for vaccine development. MICROBIOLOGY-SGM 2017; 163:1371-1384. [PMID: 28893369 DOI: 10.1099/mic.0.000523] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Moraxella catarrhalis is a human-restricted opportunistic bacterial pathogen of the respiratory mucosa. It frequently colonizes the nasopharynx asymptomatically, but is also an important causative agent of otitis media (OM) in children, and plays a significant role in acute exacerbations of chronic obstructive pulmonary disease (COPD) in adults. As the current treatment options for M. catarrhalis infection in OM and exacerbations of COPD are often ineffective, the development of an efficacious vaccine is warranted. However, no vaccine candidates for M. catarrhalis have progressed to clinical trials, and information regarding the distribution of M. catarrhalis virulence factors and vaccine candidates is inconsistent in the literature. It is largely unknown if virulence is associated with particular strains or subpopulations of M. catarrhalis, or if differences in clinical manifestation can be attributed to the heterogeneous expression of specific M. catarrhalis virulence factors in the circulating population. Further investigation of the distribution of M. catarrhalis virulence factors in the context of carriage and disease is required so that vaccine development may be targeted at relevant antigens that are conserved among disease-causing strains. The challenge of determining which of the proposed M. catarrhalis virulence factors are relevant to human disease is amplified by the lack of a standardized M. catarrhalis typing system to facilitate direct comparisons of worldwide isolates. Here we summarize and evaluate proposed relationships between M. catarrhalis subpopulations and specific virulence factors in the context of colonization and disease, as well as the current methods used to infer these associations.
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Affiliation(s)
- Luke V Blakeway
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Aimee Tan
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Ian R A Peak
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.,School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
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Earl JP, de Vries SPW, Ahmed A, Powell E, Schultz MP, Hermans PWM, Hill DJ, Zhou Z, Constantinidou CI, Hu FZ, Bootsma HJ, Ehrlich GD. Comparative Genomic Analyses of the Moraxella catarrhalis Serosensitive and Seroresistant Lineages Demonstrate Their Independent Evolution. Genome Biol Evol 2016; 8:955-74. [PMID: 26912404 PMCID: PMC4860680 DOI: 10.1093/gbe/evw039] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2016] [Indexed: 02/07/2023] Open
Abstract
The bacterial speciesMoraxella catarrhalishas been hypothesized as being composed of two distinct lineages (referred to as the seroresistant [SR] and serosensitive [SS]) with separate evolutionary histories based on several molecular typing methods, whereas 16S ribotyping has suggested an additional split within the SS lineage. Previously, we characterized whole-genome sequences of 12 SR-lineage isolates, which revealed a relatively small supragenome when compared with other opportunistic nasopharyngeal pathogens, suggestive of a relatively short evolutionary history. Here, we performed whole-genome sequencing on 18 strains from both ribotypes of the SS lineage, an additional SR strain, as well as four previously identified highly divergent strains based on multilocus sequence typing analyses. All 35 strains were subjected to a battery of comparative genomic analyses which clearly show that there are three lineages-the SR, SS, and the divergent. The SR and SS lineages are closely related, but distinct from each other based on three different methods of comparison: Allelic differences observed among core genes; possession of lineage-specific sets of core and distributed genes; and by an alignment of concatenated core sequences irrespective of gene annotation. All these methods show that the SS lineage has much longer interstrain branches than the SR lineage indicating that this lineage has likely been evolving either longer or faster than the SR lineage. There is evidence of extensive horizontal gene transfer (HGT) within both of these lineages, and to a lesser degree between them. In particular, we identified very high rates of HGT between these two lineages for ß-lactamase genes. The four divergent strains aresui generis, being much more distantly related to both the SR and SS groups than these other two groups are to each other. Based on average nucleotide identities, gene content, GC content, and genome size, this group could be considered as a separate taxonomic group. The SR and SS lineages, although distinct, clearly form a single species based on multiple criteria including a large common core genome, average nucleotide identity values, GC content, and genome size. Although neither of these lineages arose from within the other based on phylogenetic analyses, the question of how and when these lineages split and then subsequently reunited in the human nasopharynx is explored.
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Affiliation(s)
- Joshua P Earl
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA Center for Genomic Sciences and Center for Advanced Microbial Processing, Institute of Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA Center for Genomic Sciences, Allegheny-Singer Research Institute, Allegheny General Hospital, Pittsburgh, PA
| | - Stefan P W de Vries
- Present address: Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom Laboratory of Pediatric Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Azad Ahmed
- Center for Genomic Sciences, Allegheny-Singer Research Institute, Allegheny General Hospital, Pittsburgh, PA
| | - Evan Powell
- Center for Genomic Sciences, Allegheny-Singer Research Institute, Allegheny General Hospital, Pittsburgh, PA
| | - Matthew P Schultz
- Center for Genomic Sciences, Allegheny-Singer Research Institute, Allegheny General Hospital, Pittsburgh, PA
| | - Peter W M Hermans
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Darryl J Hill
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Zhemin Zhou
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | - Fen Z Hu
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA Center for Genomic Sciences and Center for Advanced Microbial Processing, Institute of Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA Center for Genomic Sciences, Allegheny-Singer Research Institute, Allegheny General Hospital, Pittsburgh, PA Department of Otolaryngology Head and Neck Surgery, Drexel University College of Medicine, Philadelphia, PA
| | - Hester J Bootsma
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Garth D Ehrlich
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA Center for Genomic Sciences and Center for Advanced Microbial Processing, Institute of Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA Center for Genomic Sciences, Allegheny-Singer Research Institute, Allegheny General Hospital, Pittsburgh, PA Department of Otolaryngology Head and Neck Surgery, Drexel University College of Medicine, Philadelphia, PA
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Abstract
INTRODUCTION Moraxella catarrhalis is a prominent pathogen that causes acute otitis media in children and lower respiratory tract infections in adults, resulting in a significant socioeconomic burden on healthcare systems globally. No vaccine is currently available for M. catarrhalis. Promising M. catarrhalis target antigens have been characterized in animal models and should soon enter human clinical trials. AREAS COVERED This review discusses the detailed features and research status of current candidate target antigens for an M. catarrhalis vaccine. The approaches for assessing M. catarrhalis vaccine efficacy are also discussed. EXPERT OPINION Targeting the key molecules contributing to serum resistance may be a viable strategy to identify effective vaccine targets among M. catarrhalis antigens. Elucidating the role and mechanisms of the serum and mucosal immune responses to M. catarrhalis is significant for vaccine target selection, testing and evaluation. Developing animal models closely simulating M. catarrhalis-caused human respiratory diseases is of great benefit in better understanding pathogenesis and evaluating vaccine efficacy. Carrying out clinical trials will be a landmark in the progress of M. catarrhalis vaccine research. Combined multicomponent vaccines will be a focus of future M. catarrhalis vaccine studies.
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Affiliation(s)
- Dabin Ren
- a 1 Research Institute, Rochester General Hospital , 1425 Portland Avenue, Rochester, NY, USA +1 585 922 3706 ;
| | - Michael E Pichichero
- b 2 Research Institute, Rochester General Hospital , 1425 Portland Avenue, Rochester, NY, USA
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16
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Identification and therapeutic potential of a vitronectin binding region of meningococcal msf. PLoS One 2015; 10:e0124133. [PMID: 25826209 PMCID: PMC4380367 DOI: 10.1371/journal.pone.0124133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 03/13/2015] [Indexed: 01/06/2023] Open
Abstract
The human pathogen Neisseria meningitides (Nm) attains serum resistance via a number of mechanisms, one of which involves binding to the host complement regulator protein vitronectin. We have shown previously that the Meningococcal surface fibril (Msf), a trimeric autotransporter, binds to the activated form of vitronectin (aVn) to increase Nm survival in human serum. In this study, we aimed to identify the aVn-binding region of Msf to assess its potential as an antigen which can elicit antibodies that block aVn binding and/or possess bactericidal properties. Using several recombinant Msf fragments spanning its surface-exposed region, the smallest aVn-binding recombinants were found to span residues 1-86 and 39-124. The use of further deletion constructs and overlapping recombinant Msf fragments suggested that a region of Msf comprising residues 39-82 may be primarily important for aVn binding and that other regions may also be involved but to a lesser extent. Molecular modelling implicated K66 and K68, conserved in all available Msf sequences, to be involved in the interaction. Recombinant fragments which bound to aVn were able to reduce the survival advantage conveyed by aVn-interaction in serum bactericidal assays. Antibodies raised against one such fragment inhibited aVn binding to Msf. In addition, the antibodies enhanced specific killing of Msf-expressing Nm in a dose-dependent manner. Overall, this study identifies an aVn-binding region of Msf, an adhesin known to impart serum resistance properties to the pathogen; and shows that this region of Msf can elicit antibodies with dual properties which reduce pathogen survival within the host and thus has potential as a vaccine antigen.
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Xie Q, Brackenbury LS, Hill DJ, Williams NA, Qu X, Virji M. Moraxella catarrhalis adhesin UspA1-derived recombinant fragment rD-7 induces monocyte differentiation to CD14+CD206+ phenotype. PLoS One 2014; 9:e90999. [PMID: 24599281 PMCID: PMC3944954 DOI: 10.1371/journal.pone.0090999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 02/06/2014] [Indexed: 12/04/2022] Open
Abstract
Circulating monocytes in the bloodstream typically migrate to other tissues and differentiate into tissue resident macrophages, the process being determined by the constituents of the microenvironments encountered. These may include microbes and their products. In this study, we investigated whether Moraxella catarrhalis Ubiquitous Surface Protein A1 (UspA1), known to bind to a widely expressed human cell surface receptor CEACAM1, influences monocyte differentiation as receptor engagement has been shown to have profound effects on monocytes. We used the recombinant molecules corresponding to the regions of UspA1 which either bind (rD-7; UspA1527–665) or do not bind (r6–8; UspA1659–863) to CEACAM1 and investigated their effects on CD206, CD80 and CD86 expression on freshly isolated human CD14+ monocytes from peripheral blood mononuclear cells (PBMC). Exposure to rD-7, but not r6–8, biased monocyte differentiation towards a CD14+CD206+ phenotype, with reduced CD80 expression. Monocytes treated with rD-7 also secreted high levels of IL-1ra and chemokine IL-8 but not IL-10 or IL-12p70. The effects of rD-7 were independent of any residual endotoxin. Unexpectedly, these effects of rD-7 were also independent of its ability to bind to CEACAM1, as monocyte pre-treatment with the anti-CEACAM antibody A0115 known to inhibit rD-7 binding to the receptor, did not affect rD-7-driven differentiation. Further, another control protein rD-7/D (a mutant form of rD-7, known not to bind to CEACAMs), also behaved as the parent molecule. Our data suggest that specific regions of M. catarrhalis adhesin UspA1 may modulate inflammation during infection through a yet unknown receptor on monocytes.
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Affiliation(s)
- Qi Xie
- Institute of Basic Medical Sciences, Qilu Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Louise S. Brackenbury
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Darryl J. Hill
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Neil A. Williams
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- * E-mail: (XQ); (NW)
| | - Xun Qu
- Institute of Basic Medical Sciences, Qilu Hospital, Shandong University, Jinan, Shandong, P.R. China
- * E-mail: (XQ); (NW)
| | - Mumtaz Virji
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
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18
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de Vries SPW, Rademakers RJA, van der Gaast-de Jongh CE, Eleveld MJ, Hermans PWM, Bootsma HJ. Deciphering the genetic basis ofMoraxella catarrhaliscomplement resistance: a critical role for the disulphide bond formation system. Mol Microbiol 2013; 91:522-37. [DOI: 10.1111/mmi.12475] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2013] [Indexed: 12/14/2022]
Affiliation(s)
- Stefan P. W. de Vries
- Laboratory of Pediatric Infectious Diseases; Radboud University Medical Centre; Nijmegen The Netherlands
| | - Rob J. A. Rademakers
- Laboratory of Pediatric Infectious Diseases; Radboud University Medical Centre; Nijmegen The Netherlands
| | | | - Marc J. Eleveld
- Laboratory of Pediatric Infectious Diseases; Radboud University Medical Centre; Nijmegen The Netherlands
| | - Peter W. M. Hermans
- Laboratory of Pediatric Infectious Diseases; Radboud University Medical Centre; Nijmegen The Netherlands
| | - Hester J. Bootsma
- Laboratory of Pediatric Infectious Diseases; Radboud University Medical Centre; Nijmegen The Netherlands
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Shaffer TL, Balder R, Buskirk SW, Hogan RJ, Lafontaine ER. Use of the Chinchilla model to evaluate the vaccinogenic potential of the Moraxella catarrhalis filamentous hemagglutinin-like proteins MhaB1 and MhaB2. PLoS One 2013; 8:e67881. [PMID: 23844117 PMCID: PMC3699455 DOI: 10.1371/journal.pone.0067881] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/23/2013] [Indexed: 11/19/2022] Open
Abstract
Moraxella catarrhalis causes significant health problems, including 15–20% of otitis media cases in children and ∼10% of respiratory infections in adults with chronic obstructive pulmonary disease. The lack of an efficacious vaccine, the rapid emergence of antibiotic resistance in clinical isolates, and high carriage rates reported in children are cause for concern. In addition, the effectiveness of conjugate vaccines at reducing the incidence of otitis media caused by Streptococcus pneumoniae and nontypeable Haemophilus influenzae suggest that M. catarrhalis infections may become even more prevalent. Hence, M. catarrhalis is an important and emerging cause of infectious disease for which the development of a vaccine is highly desirable. Studying the pathogenesis of M. catarrhalis and the testing of vaccine candidates have both been hindered by the lack of an animal model that mimics human colonization and infection. To address this, we intranasally infected chinchilla with M. catarrhalis to investigate colonization and examine the efficacy of a protein-based vaccine. The data reveal that infected chinchillas produce antibodies against antigens known to be major targets of the immune response in humans, thus establishing immune parallels between chinchillas and humans during M. catarrhalis infection. Our data also demonstrate that a mutant lacking expression of the adherence proteins MhaB1 and MhaB2 is impaired in its ability to colonize the chinchilla nasopharynx, and that immunization with a polypeptide shared by MhaB1 and MhaB2 elicits antibodies interfering with colonization. These findings underscore the importance of adherence proteins in colonization and emphasize the relevance of the chinchilla model to study M. catarrhalis–host interactions.
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Affiliation(s)
- Teresa L. Shaffer
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Rachel Balder
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Sean W. Buskirk
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Robert J. Hogan
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia, Athens, Georgia, United States of America
| | - Eric R. Lafontaine
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Spaniol V, Wyder S, Aebi C. RNA-Seq-based analysis of the physiologic cold shock-induced changes in Moraxella catarrhalis gene expression. PLoS One 2013; 8:e68298. [PMID: 23844181 PMCID: PMC3699543 DOI: 10.1371/journal.pone.0068298] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/28/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Moraxella catarrhalis, a major nasopharyngeal pathogen of the human respiratory tract, is exposed to rapid downshifts of environmental temperature when humans breathe cold air. The prevalence of pharyngeal colonization and respiratory tract infections caused by M. catarrhalis is greatest in winter. We investigated how M. catarrhalis uses the physiologic exposure to cold air to regulate pivotal survival systems that may contribute to M. catarrhalis virulence. RESULTS In this study we used the RNA-seq techniques to quantitatively catalogue the transcriptome of M. catarrhalis exposed to a 26 °C cold shock or to continuous growth at 37 °C. Validation of RNA-seq data using quantitative RT-PCR analysis demonstrated the RNA-seq results to be highly reliable. We observed that a 26 °C cold shock induces the expression of genes that in other bacteria have been related to virulence a strong induction was observed for genes involved in high affinity phosphate transport and iron acquisition, indicating that M. catarrhalis makes a better use of both phosphate and iron resources after exposure to cold shock. We detected the induction of genes involved in nitrogen metabolism, as well as several outer membrane proteins, including ompA, m35-like porin and multidrug efflux pump (acrAB) indicating that M. catarrhalis remodels its membrane components in response to downshift of temperature. Furthermore, we demonstrate that a 26 °C cold shock enhances the induction of genes encoding the type IV pili that are essential for natural transformation, and increases the genetic competence of M. catarrhalis, which may facilitate the rapid spread and acquisition of novel virulence-associated genes. CONCLUSION Cold shock at a physiologically relevant temperature of 26 °C induces in M. catarrhalis a complex of adaptive mechanisms that could convey novel pathogenic functions and may contribute to enhanced colonization and virulence.
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Affiliation(s)
- Violeta Spaniol
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
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21
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Su YC, Hallström BM, Bernhard S, Singh B, Riesbeck K. Impact of sequence diversity in the Moraxella catarrhalis UspA2/UspA2H head domain on vitronectin binding and antigenic variation. Microbes Infect 2013; 15:375-87. [DOI: 10.1016/j.micinf.2013.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/15/2013] [Accepted: 02/11/2013] [Indexed: 12/31/2022]
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22
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Voss S, Hallström T, Saleh M, Burchhardt G, Pribyl T, Singh B, Riesbeck K, Zipfel PF, Hammerschmidt S. The choline-binding protein PspC of Streptococcus pneumoniae interacts with the C-terminal heparin-binding domain of vitronectin. J Biol Chem 2013; 288:15614-27. [PMID: 23603906 DOI: 10.1074/jbc.m112.443507] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Adherence of Streptococcus pneumoniae is directly mediated by interactions of adhesins with eukaryotic cellular receptors or indirectly by exploiting matrix and serum proteins as molecular bridges. Pneumococci engage vitronectin, the human adhesive glycoprotein and complement inhibitor, to facilitate attachment to epithelial cells of the mucosal cavity, thereby modulating host cell signaling. In this study, we identified PspC as a vitronectin-binding protein interacting with the C-terminal heparin-binding domain of vitronectin. PspC is a multifunctional surface-exposed choline-binding protein displaying various adhesive properties. Vitronectin binding required the R domains in the mature PspC protein, which are also essential for the interaction with the ectodomain of the polymeric immunoglobulin receptor and secretory IgA. Consequently, secretory IgA competitively inhibited binding of vitronectin to purified PspC and to PspC-expressing pneumococci. In contrast, Factor H, which binds to the N-terminal part of mature PspC molecules, did not interfere with the PspC-vitronectin interaction. Using a series of vitronectin peptides, the C-terminal heparin-binding domain was shown to be essential for the interaction of soluble vitronectin with PspC. Binding experiments with immobilized vitronectin suggested a region N-terminal to the identified heparin-binding domain as an additional binding region for PspC, suggesting that soluble, immobilized, as well as cellularly bound vitronectin possesses different conformations. Finally, vitronectin bound to PspC was functionally active and inhibited the deposition of the terminal complement complex. In conclusion, this study identifies and characterizes (on the molecular level) the interaction between the pneumococcal adhesin PspC and the human glycoprotein vitronectin.
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Affiliation(s)
- Sylvia Voss
- Department of Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, D-17487 Greifswald, Germany
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