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Jin X, Gou Y, Xin Y, Li J, Sun J, Li T, Feng J. Advancements in understanding the molecular and immune mechanisms of Bartonella pathogenicity. Front Microbiol 2023; 14:1196700. [PMID: 37362930 PMCID: PMC10288214 DOI: 10.3389/fmicb.2023.1196700] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/23/2023] [Indexed: 06/28/2023] Open
Abstract
Bartonellae are considered to be emerging opportunistic pathogens. The bacteria are transmitted by blood-sucking arthropods, and their hosts are a wide range of mammals including humans. After a protective barrier breach in mammals, Bartonella colonizes endothelial cells (ECs), enters the bloodstream, and infects erythrocytes. Current research primarily focuses on investigating the interaction between Bartonella and ECs and erythrocytes, with recent attention also paid to immune-related aspects. Various molecules related to Bartonella's pathogenicity have been identified. The present review aims to provide a comprehensive overview of the newly described molecular and immune responses associated with Bartonella's pathogenicity.
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Affiliation(s)
- Xiaoxia Jin
- Gansu Provincial Key Laboratory of Evidence Based Medicine and Clinical Translation and Lanzhou Center for Tuberculosis Research, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Yuze Gou
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou, China
| | - Yuxian Xin
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou, China
| | - Jingwei Li
- Gansu Provincial Key Laboratory of Evidence Based Medicine and Clinical Translation and Lanzhou Center for Tuberculosis Research, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Jingrong Sun
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou, China
| | - Tingting Li
- Gansu Provincial Key Laboratory of Evidence Based Medicine and Clinical Translation and Lanzhou Center for Tuberculosis Research, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Jie Feng
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou, China
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou, China
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2
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Godbold GD, Hewitt FC, Kappell AD, Scholz MB, Agar SL, Treangen TJ, Ternus KL, Sandbrink JB, Koblentz GD. Improved understanding of biorisk for research involving microbial modification using annotated sequences of concern. Front Bioeng Biotechnol 2023; 11:1124100. [PMID: 37180048 PMCID: PMC10167326 DOI: 10.3389/fbioe.2023.1124100] [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: 12/14/2022] [Accepted: 04/11/2023] [Indexed: 05/15/2023] Open
Abstract
Regulation of research on microbes that cause disease in humans has historically been focused on taxonomic lists of 'bad bugs'. However, given our increased knowledge of these pathogens through inexpensive genome sequencing, 5 decades of research in microbial pathogenesis, and the burgeoning capacity of synthetic biologists, the limitations of this approach are apparent. With heightened scientific and public attention focused on biosafety and biosecurity, and an ongoing review by US authorities of dual-use research oversight, this article proposes the incorporation of sequences of concern (SoCs) into the biorisk management regime governing genetic engineering of pathogens. SoCs enable pathogenesis in all microbes infecting hosts that are 'of concern' to human civilization. Here we review the functions of SoCs (FunSoCs) and discuss how they might bring clarity to potentially problematic research outcomes involving infectious agents. We believe that annotation of SoCs with FunSoCs has the potential to improve the likelihood that dual use research of concern is recognized by both scientists and regulators before it occurs.
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Affiliation(s)
| | | | | | | | - Stacy L. Agar
- Signature Science, LLC, Charlottesville, VA, United States
| | - Todd J. Treangen
- Department of Computer Science, Rice University, Houston, TX, United States
| | | | - Jonas B. Sandbrink
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Gregory D. Koblentz
- Schar School of Policy and Government, George Mason University, Arlington, VA, United States
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3
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Yoshimoto S, Aoki S, Ohara Y, Ishikawa M, Suzuki A, Linke D, Lupas AN, Hori K. Identification of the adhesive domain of AtaA from Acinetobacter sp. Tol 5 and its application in immobilizing Escherichia coli. Front Bioeng Biotechnol 2023; 10:1095057. [PMID: 36698637 PMCID: PMC9868564 DOI: 10.3389/fbioe.2022.1095057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/21/2022] [Indexed: 01/11/2023] Open
Abstract
Cell immobilization is an important technique for efficiently utilizing whole-cell biocatalysts. We previously invented a method for bacterial cell immobilization using AtaA, a trimeric autotransporter adhesin from the highly sticky bacterium Acinetobacter sp. Tol 5. However, except for Acinetobacter species, only one bacterium has been successfully immobilized using AtaA. This is probably because the heterologous expression of large AtaA (1 MDa), that is a homotrimer of polypeptide chains composed of 3,630 amino acids, is difficult. In this study, we identified the adhesive domain of AtaA and constructed a miniaturized AtaA (mini-AtaA) to improve the heterologous expression of ataA. In-frame deletion mutants were used to perform functional mapping, revealing that the N-terminal head domain is essential for the adhesive feature of AtaA. The mini-AtaA, which contains a homotrimer of polypeptide chains from 775 amino acids and lacks the unnecessary part for its adhesion, was properly expressed in E. coli, and a larger amount of molecules was displayed on the cell surface than that of full-length AtaA (FL-AtaA). The immobilization ratio of E. coli cells expressing mini-AtaA on a polyurethane foam support was significantly higher compared to the cells with or without FL-AtaA expression, respectively. The expression of mini-AtaA in E. coli had little effect on the cell growth and the activity of another enzyme reflecting the production level, and the immobilized E. coli cells could be used for repetitive enzymatic reactions as a whole-cell catalyst.
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Affiliation(s)
- Shogo Yoshimoto
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Sota Aoki
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Yuki Ohara
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Masahito Ishikawa
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Atsuo Suzuki
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Andrei N. Lupas
- Department of Protein Evolution, Max Planck Institute for Biology, Tübingen, Germany
| | - Katsutoshi Hori
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan,*Correspondence: Katsutoshi Hori,
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4
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Categorizing sequences of concern by function to better assess mechanisms of microbial pathogenesis. Infect Immun 2021; 90:e0033421. [PMID: 34780277 PMCID: PMC9119117 DOI: 10.1128/iai.00334-21] [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] [Indexed: 11/23/2022] Open
Abstract
To identify sequences with a role in microbial pathogenesis, we assessed the adequacy of their annotation by existing controlled vocabularies and sequence databases. Our goal was to regularize descriptions of microbial pathogenesis for improved integration with bioinformatic applications. Here, we review the challenges of annotating sequences for pathogenic activity. We relate the categorization of more than 2,750 sequences of pathogenic microbes through a controlled vocabulary called Functions of Sequences of Concern (FunSoCs). These allow for an ease of description by both humans and machines. We provide a subset of 220 fully annotated sequences in the supplemental material as examples. The use of this compact (∼30 terms), controlled vocabulary has potential benefits for research in microbial genomics, public health, biosecurity, biosurveillance, and the characterization of new and emerging pathogens.
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Vaca DJ, Thibau A, Schütz M, Kraiczy P, Happonen L, Malmström J, Kempf VAJ. Interaction with the host: the role of fibronectin and extracellular matrix proteins in the adhesion of Gram-negative bacteria. Med Microbiol Immunol 2019; 209:277-299. [PMID: 31784893 PMCID: PMC7248048 DOI: 10.1007/s00430-019-00644-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/14/2019] [Indexed: 01/03/2023]
Abstract
The capacity of pathogenic microorganisms to adhere to host cells and avoid clearance by the host immune system is the initial and most decisive step leading to infections. Bacteria have developed different strategies to attach to diverse host surface structures. One important strategy is the adhesion to extracellular matrix (ECM) proteins (e.g., collagen, fibronectin, laminin) that are highly abundant in connective tissue and basement membranes. Gram-negative bacteria express variable outer membrane proteins (adhesins) to attach to the host and to initiate the process of infection. Understanding the underlying molecular mechanisms of bacterial adhesion is a prerequisite for targeting this interaction by “anti-ligands” to prevent colonization or infection of the host. Future development of such “anti-ligands” (specifically interfering with bacteria-host matrix interactions) might result in the development of a new class of anti-infective drugs for the therapy of infections caused by multidrug-resistant Gram-negative bacteria. This review summarizes our current knowledge about the manifold interactions of adhesins expressed by Gram-negative bacteria with ECM proteins and the use of this information for the generation of novel therapeutic antivirulence strategies.
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Affiliation(s)
- Diana J Vaca
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Str. 40, 60596, Frankfurt, Germany
| | - Arno Thibau
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Str. 40, 60596, Frankfurt, Germany
| | - Monika Schütz
- Institute for Medical Microbiology and Infection Control, University Hospital, Eberhard Karls-University, Tübingen, Germany
| | - Peter Kraiczy
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Str. 40, 60596, Frankfurt, Germany
| | - Lotta Happonen
- Division of Infection Medicine, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Johan Malmström
- Division of Infection Medicine, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Volkhard A J Kempf
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University Frankfurt am Main, Paul-Ehrlich-Str. 40, 60596, Frankfurt, Germany.
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Sequential Translocation of Polypeptides across the Bacterial Outer Membrane through the Trimeric Autotransporter Pathway. mBio 2019; 10:mBio.01973-19. [PMID: 31641085 PMCID: PMC6805991 DOI: 10.1128/mbio.01973-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Trimeric autotransporter adhesins (TAAs) are a family of bacterial outer membrane (OM) proteins that are comprised of three identical subunits. Each subunit contains an N-terminal extracellular ("passenger") domain and a short C-terminal segment that contributes four β strands to a single 12-stranded β barrel. The mechanism by which the passenger domains are translocated across the OM and the energetics of the translocation reaction are poorly understood. To address these issues, we examined the secretion of modified versions of the passenger domain of UpaG, a TAA produced by Escherichia coli CFT073. Using the SpyTag-SpyCatcher system to probe passenger domain localization, we found that both intrinsically disordered polypeptides fused to the UpaG passenger domain and artificially disulfide-bonded polypeptides were secreted effectively but relatively slowly. Surprisingly, we also found that in some cases, the three nonnative passenger domain segments associated with a single trimer were secreted sequentially. Photo-cross-linking experiments indicated that incompletely assembled UpaG derivatives remained bound to the barrel assembly machinery (Bam) complex until all three passenger domains were fully secreted. Taken together, our results strongly suggest that the secretion of polypeptides through the TAA pathway is coordinated with the assembly of the β barrel domain and that the folding of passenger domains in the extracellular space maximizes the rate of secretion. Furthermore, our work provides evidence for an unprecedented sequential mode of protein translocation, at least under specific experimental conditions.IMPORTANCE Trimeric autotransporter adhesins (TAAs) are specialized bacterial outer membrane proteins consisting of three identical subunits. TAAs contain large extracellular domains that trimerize and promote virulence, but the mechanism by which they are secreted is poorly understood. We found that the extracellular domains of a native TAA were secreted rapidly but that disordered and artificially folded polypeptides fused to native passenger domains were secreted in a slow, sequential fashion. Our results strongly suggest that the efficient secretion of native extracellular domains is driven by their trimerization following export but that alternative energy sources can be harnessed to secrete nonnative polypeptides. Furthermore, we obtained evidence that TAA extracellular domains are secreted before the assembly of the linked membrane spanning domain is completed.
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Okaro U, Green R, Mohapatra S, Anderson B. The trimeric autotransporter adhesin BadA is required for in vitro biofilm formation by Bartonella henselae. NPJ Biofilms Microbiomes 2019; 5:10. [PMID: 30886729 PMCID: PMC6418236 DOI: 10.1038/s41522-019-0083-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 02/01/2019] [Indexed: 01/10/2023] Open
Abstract
Bartonella henselae (Bh) is a Gram-negative rod transmitted to humans by a scratch from the common house cat. Infection of humans with Bh can result in a range of clinical diseases including lymphadenopathy observed in cat-scratch disease and more serious disease from persistent bacteremia. It is a common cause of blood-culture negative endocarditis as the bacterium is capable of growing as aggregates, and forming biofilms on infected native and prosthetic heart valves. The aggregative growth requires a trimeric autotransporter adhesin (TAA) called Bartonella adhesin A (BadA). TAAs are found in all Bartonella species and many other Gram-negative bacteria. Using Bh Houston-1, Bh Houston-1 ∆badA and Bh Houston-1 ∆badA/pNS2PTrc badA (a partial complement of badA coding for a truncated protein of 741 amino acid residues), we analyze the role of BadA in adhesion and biofilm formation. We also investigate the role of environmental factors such as temperature on badA expression and biofilm formation. Real-time cell adhesion monitoring and electron microscopy show that Bh Houston-1 adheres and forms biofilm more efficiently than the Bh Houston-1 ∆badA. Deletion of the badA gene significantly decreases adhesion, the first step in biofilm formation in vitro, which is partially restored in Bh Houston-1 ∆badA/pNS2PTrc badA. The biofilm formed by Bh Houston-1 includes polysaccharides, proteins, and DNA components and is susceptible to enzymatic degradation of these components. Furthermore, both pH and temperature influence both badA expression and biofilm formation. We conclude that BadA is required for optimal adhesion, agglutination and biofilm formation.
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Affiliation(s)
- Udoka Okaro
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Ryan Green
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Subhra Mohapatra
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Burt Anderson
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
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8
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Deng H, Pang Q, Zhao B, Vayssier-Taussat M. Molecular Mechanisms of Bartonella and Mammalian Erythrocyte Interactions: A Review. Front Cell Infect Microbiol 2018; 8:431. [PMID: 30619777 PMCID: PMC6299047 DOI: 10.3389/fcimb.2018.00431] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/30/2018] [Indexed: 12/18/2022] Open
Abstract
Bartonellosis is an infectious disease caused by Bartonella species that are distributed worldwide with animal and public health impact varying according to Bartonella species, infection phase, immunological characteristics, and geographical region. Bartonella is widely present in various mammals including cats, rodents, ruminants, and humans. At least 13 Bartonella species or subspecies are zoonotic. Each species has few reservoir animals in which it is often asymptomatic. Bartonella infection may lead to various clinical symptoms in humans. As described in the B.tribocorum-rat model, when Bartonella was seeded into the blood stream, they could escape immunity, adhered to and invaded host erythrocytes. They then replicated and persisted in the infected erythrocytes for several weeks. This review summarizes the current knowledge of how Bartonella prevent phagocytosis and complement activation, what pathogenesis factors are involved in erythrocyte adhesion and invasion, and how Bartonella could replicate and persist in mammalian erythrocytes. Current advances in research will help us to decipher molecular mechanisms of interactions between Bartonella and mammalian erythrocytes and may help in the development of biological strategies for the prevention and control of bartonellosis.
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Affiliation(s)
- Hongkuan Deng
- School of Life Sciences, Shandong University of Technology, Zibo, China
| | - Qiuxiang Pang
- School of Life Sciences, Shandong University of Technology, Zibo, China
| | - Bosheng Zhao
- School of Life Sciences, Shandong University of Technology, Zibo, China
| | - Muriel Vayssier-Taussat
- UMR BIPAR, INRA, ANSES, École Nationale Vétérinaire d'Alfort, Université Paris-Est Créteil Val-de-Marne, Maisons-Alfort, France
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9
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Jong WSP, Schillemans M, ten Hagen-Jongman CM, Luirink J, van Ulsen P. Comparing autotransporter β-domain configurations for their capacity to secrete heterologous proteins to the cell surface. PLoS One 2018; 13:e0191622. [PMID: 29415042 PMCID: PMC5802855 DOI: 10.1371/journal.pone.0191622] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/08/2018] [Indexed: 01/11/2023] Open
Abstract
Monomeric autotransporters have been extensively used for export of recombinant proteins to the cell surface of Gram-negative bacteria. A bottleneck in the biosynthesis of such constructs is the passage of the outer membrane, which is facilitated by the β-domain at the C terminus of an autotransporter in conjunction with the Bam complex in the outer membrane. We have evaluated eight β-domain constructs for their capacity to secrete fused proteins to the cell surface. These constructs derive from the monomeric autotransporters Hbp, IgA protease, Ag43 and EstA and the trimeric autotransporter Hia, which all were selected because they have been previously used for secretion of recombinant proteins. We fused three different protein domains to the eight β-domain constructs, being a Myc-tag, the Hbp passenger and a nanobody or VHH domain, and assessed expression, membrane insertion and surface exposure. Our results show that expression levels differed considerably between the constructs tested. The constructs that included the β-domains of Hbp and IgA protease appeared the most efficient and resulted in expression levels that were detectable on Coomassie-stained SDS-PAGE gels. The VHH domain appeared the most difficult fusion partner to export, probably due to its complex immunoglobulin-like structure with a tertiary structure stabilized by an intramolecular disulfide bond. Overall, the Hbp β-domain compared favorably in exporting the fused recombinant proteins, because it showed in every instance tested a good level of expression, stable membrane insertion and clear surface exposure.
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Affiliation(s)
- Wouter S. P. Jong
- Section Molecular Microbiology, Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Abera Bioscience AB, Stockholm, Sweden
- * E-mail: ;
| | | | - Corinne M. ten Hagen-Jongman
- Section Molecular Microbiology, Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Joen Luirink
- Section Molecular Microbiology, Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Abera Bioscience AB, Stockholm, Sweden
| | - Peter van Ulsen
- Section Molecular Microbiology, Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- * E-mail: ;
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Abstract
Type V secretion denotes a variety of secretion systems that cross the outer membrane in Gram-negative bacteria but that depend on the Sec machinery for transport through the inner membrane. They are possibly the simplest bacterial secretion systems, because they consist only of a single polypeptide chain (or two chains in the case of two-partner secretion). Their seemingly autonomous transport through the outer membrane has led to the term "autotransporters" for various subclasses of type V secretion. In this chapter, we review the structure and function of these transporters and review recent findings on additional factors involved in the secretion process, which have put the term "autotransporter" to debate.
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11
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Wang L, Qin W, Zhang J, Bao C, Zhang H, Che Y, Sun C, Gu J, Feng X, Du C, Han W, Richard PL, Lei L. Adh enhances Actinobacillus pleuropneumoniae pathogenicity by binding to OR5M11 and activating p38 which induces apoptosis of PAMs and IL-8 release. Sci Rep 2016; 6:24058. [PMID: 27046446 PMCID: PMC4820727 DOI: 10.1038/srep24058] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 03/21/2016] [Indexed: 12/16/2022] Open
Abstract
Members of the Trimeric Autotransporter Adhesin (TAA) family play a crucial role in the adhesion of Gram-negative pathogens to host cells, but the immunopathogenesis of TAAs remains unknown. Our previous studies demonstrated that Adh from Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is required for full bacterial pathogenicity. Alveolar macrophages are the first line of defense against respiratory infections. This study compared the interactions between porcine alveolar macrophages (PAMs) and wild-type A. pleuropneumoniae (5b WT) or an Adh-deletion strain (5b ΔAdh) via gene microarray, immunoprecipitation and other technologies. We found that Adh was shown to interact with the PAMs membrane protein OR5M11, an olfactory receptor, resulting in the high-level secretion of IL-8 by activation of p38 MAPK signaling pathway. Subsequently, PAMs apoptosis via the activation of the Fax and Bax signaling pathways was observed, followed by activation of caspases 8, 9, and 3. The immunological pathogenic roles of Adh were also confirmed in both murine and piglets infectious models in vivo. These results identify a novel immunological strategy for TAAs to boost the pathogenicity of A. pleuropneumoniae. Together, these datas reveal the high versatility of the Adh protein as a virulence factor and provide novel insight into the immunological pathogenic role of TAAs.
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Affiliation(s)
- Lei Wang
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China.,College of Animal Science, Henan Institute of Science and Technology, Xinxiang, P. R. China
| | - Wanhai Qin
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | - Jing Zhang
- Changchun University of Chinese Medicine, Changchun, P. R. China
| | - Chuntong Bao
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | - Hu Zhang
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | - Yanyi Che
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | - Changjiang Sun
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | - Jingmin Gu
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | - Xin Feng
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | - Chongtao Du
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | - Wenyu Han
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
| | | | - Liancheng Lei
- College of Veterinary Medicine, JiLin University, Changchun, P. R. China
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12
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Abstract
UNLABELLED Moraxella catarrhalis is a human respiratory pathogen that causes acute otitis media in children and is associated with exacerbations in patients suffering from chronic obstructive pulmonary disease (COPD). The first step in M. catarrhalis colonization is adherence to the mucosa, epithelial cells, and extracellular matrix (ECM). The objective of this study was to evaluate the role of M. catarrhalis interactions with collagens from various angles. Clinical isolates (n= 43) were tested for collagen binding, followed by a detailed analysis of protein-protein interactions using recombinantly expressed proteins.M. catarrhalis-dependent interactions with collagen produced by human lung fibroblasts and tracheal tissues were studied by utilizing confocal immunohistochemistry and high-resolution scanning electron microscopy. A mouse smoke-induced chronic obstructive pulmonary disease (COPD) model was used to estimate the adherence of M. catarrhalis in vivo. We found that all M. catarrhalis clinical isolates tested adhered to fibrillar collagen types I, II, and III and network-forming collagens IV and VI. The trimeric autotransporter adhesins ubiquitous surface protein A2(UspA2) and UspA2H were identified as major collagen-binding receptors.M. catarrhalis wild type adhered to human tracheal tissue and collagen-producing lung fibroblasts, whereas UspA2 and UspA2H deletion mutants did not. Moreover, in the COPD mouse model, bacteria devoid of UspA2 and UspA2H had a reduced level of adherence to the respiratory tract compared to the adherence of wild-type bacteria. Our data therefore suggest that theM. catarrhalisUspA2 and UspA2H-dependent interaction with collagens is highly critical for adherence in the host and, furthermore, may play an important role in the establishment of disease. IMPORTANCE The respiratory tract pathogen Moraxella catarrhalis adheres to the host by interacting with several components, including the ECM. Collagen accounts for 30% of total body proteins, and therefore, bacterial adherence to abundant host collagens mediates bacterial persistence and colonization. In this study, we characterized previously unknown M. catarrhalis-dependent interactions with host collagens and found that the trimeric autotransporter adhesins ubiquitous surface protein A2(UspA2) and UspA2H are highly important. Our observations also suggested that collagen-mediated adherence ofM. catarrhalis is indispensable for bacterial survival in the host, as exemplified by a mouse COPD model.
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13
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Breitschwerdt EB, Broadhurst JJ, Cherry NA. Bartonella henselae as a cause of acute-onset febrile illness in cats. JFMS Open Rep 2015; 1:2055116915600454. [PMID: 28491382 PMCID: PMC5362002 DOI: 10.1177/2055116915600454] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2015] [Indexed: 11/15/2022] Open
Abstract
Case series summary At different time points spanning 6 months, three adopted feral flea-infested cats, residing in the household of a veterinary technician, became acutely anorexic, lethargic and febrile. Enrichment blood culture/PCR using Bartonella alpha Proteobacteria growth medium (BAPGM) confirmed initial infection with the same Bartonella henselae genotype in all three cases. With the exception of anemia and neutropenia, complete blood counts, serum biochemical profiles and urinalysis results were within reference intervals. Also, tests for feline leukemia virus, feline immunodeficiency virus, Toxoplasma gondii and feline coronavirus antibodies were negative. Serial daily temperature monitoring in one case confirmed a cyclic, relapsing febrile temperature pattern during 1 month, with resolution during and after treatment with azithromycin. Bartonella henselae Western immunoblot (WB) results did not consistently correlate with BAPGM enrichment blood culture/PCR results or B henselae indirect fluorescent antibody (IFA) titers, and WB titration results were not informative for establishing antibiotic treatment failure. During the respective follow-up periods, no illnesses or additional febrile episodes were reported, despite repeat documentation of B henselae bacteremia in two cats available for follow-up (one with the same genotype and the other with a different B henselae genotype); one cat was, unfortunately, killed by dogs before follow-up testing. Relevance and novel information We conclude that microbiological diagnosis and treatment of B henselae infection in cats can be challenging, that antibody titration results and resolution of clinical abnormalities may not correlate with a therapeutic cure, and that fever and potentially neutropenia should be differential diagnostic considerations for young cats with suspected bartonellosis.
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Affiliation(s)
- Edward B Breitschwerdt
- Intracellular Pathogens Research Laboratory and the Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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