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Bialer MG, Ferrero MC, Delpino MV, Ruiz-Ranwez V, Posadas DM, Baldi PC, Zorreguieta A. Adhesive Functions or Pseudogenization of Type Va Autotransporters in Brucella Species. Front Cell Infect Microbiol 2021; 11:607610. [PMID: 33987105 PMCID: PMC8111173 DOI: 10.3389/fcimb.2021.607610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 04/01/2021] [Indexed: 01/18/2023] Open
Abstract
Adhesion to host cells is a key step for successful infection of many bacterial pathogens and may define tropism to different host tissues. To do so, bacteria display adhesins on their surfaces. Brucella is an intracellular pathogen capable of proliferating in a wide variety of cell types. It has been described that BmaC, a large protein that belongs to the classical (type Va) autotransporter family, is required for efficient adhesion of Brucella suis strain 1330 to epithelial cells and fibronectin. Here we show that B. suis 1330 harbors two other type Va autotransporters (BmaA and BmaB), which, although much smaller, share significant sequence similarities with BmaC and contain the essential domains to mediate proper protein translocation to the bacterial surface. Gain and loss of function studies indicated that BmaA, BmaB, and BmaC contribute, to a greater or lesser degree, to adhesion of B. suis 1330 to different cells such as synovial fibroblasts, osteoblasts, trophoblasts, and polarized epithelial cells as well as to extracellular matrix components. It was previously shown that BmaC localizes to a single bacterial pole. Interestingly, we observed here that, similar to BmaC, the BmaB adhesin is localized mostly at a single cell pole, reinforcing the hypothesis that Brucella displays an adhesive pole. Although Brucella species have strikingly similar genomes, they clearly differ in their host preferences. Mainly, the differences identified between species appear to be at loci encoding surface proteins. A careful in silico analysis of the putative type Va autotransporter orthologues from several Brucella strains showed that the bmaB locus from Brucella abortus and both, the bmaA and bmaC loci from Brucella melitensis are pseudogenes in all strains analyzed. Results reported here evidence that all three autotransporters play a role in the adhesion properties of B. suis 1330. However, Brucella spp. exhibit extensive variations in the repertoire of functional adhesins of the classical autotransporter family that can be displayed on the bacterial surface, making them an interesting target for future studies on host preference and tropism.
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Affiliation(s)
- Magalí G Bialer
- Fundación Instituto Leloir (FIL), IIBBA (CONICET-FIL), Buenos Aires, Argentina
| | - Mariana C Ferrero
- Facultad de Farmacia y Bioquímica, Cátedra de Inmunología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - M Victoria Delpino
- Instituto de Inmunología, Genética y Metabolismo (INIGEM), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Diana M Posadas
- Fundación Instituto Leloir (FIL), IIBBA (CONICET-FIL), Buenos Aires, Argentina
| | - Pablo C Baldi
- Facultad de Farmacia y Bioquímica, Cátedra de Inmunología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Angeles Zorreguieta
- Fundación Instituto Leloir (FIL), IIBBA (CONICET-FIL), Buenos Aires, Argentina.,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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2
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Pereira RFC, Theizen TH, Machado D, Guarnieri JPDO, Gomide GP, Hollanda LMD, Lancellotti M. Analysis of potential virulence genes and competence to transformation in Haemophilus influenzae biotype aegyptius associated with Brazilian Purpuric Fever. Genet Mol Biol 2021; 44:e20200029. [PMID: 33395458 PMCID: PMC7816109 DOI: 10.1590/1678-4685-gmb-2020-0029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 11/18/2020] [Indexed: 11/21/2022] Open
Abstract
Brazilian Purpuric Fever (BPF) is a hemorrhagic pediatric illness caused by Haemophilus influenzae biogroup aegyptius (Hae), a bacterium that was formerly associated with self-limited purulent conjunctivitis. BPF is assumed to be eradicated. However, the virulence mechanisms inherent to Hae strains associated with BPF is still a mystery and deficient in studies. Here, we aim to analyze the role of the autotransporter genes related to adherence and colonization las, tabA1, and hadA genes through RT-qPCR expression profiling and knockout mutants. Relative quantification by real-time PCR after infection in human cells and infant rat model suggests that las was initially downregulated probably duo to immune evasion, tabA1, and hadA were overexpressed in general, suggesting an active role of TabA1 and HadA1 adhesins in Hae in vitro and in vivo. Transformation attempts were unsuccessful despite the use of multiple technical approaches and in silico analysis revealed that Hae lacks genes related to competence in Haemophilus, which could be part of the elucidation of the difficulty of genetically manipulating Hae strains.
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Affiliation(s)
| | - Thais Holtz Theizen
- Universidade Estadual de Campinas, Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Campinas, SP, Brazil
| | - Daisy Machado
- Universidade Estadual de Campinas, Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Campinas, SP, Brazil
| | | | - Gabriel Piccirillo Gomide
- Universidade Estadual de Campinas - UNICAMP, Faculdade de Ciências Farmacêuticas - FCF, Campinas, SP, Brazil
| | - Luciana Maria de Hollanda
- Universidade Estadual de Campinas, Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Campinas, SP, Brazil
| | - Marcelo Lancellotti
- Universidade Estadual de Campinas, Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Campinas, SP, Brazil.,Universidade Estadual de Campinas - UNICAMP, Faculdade de Ciências Farmacêuticas - FCF, Campinas, SP, Brazil
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3
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Betanzos A, Zanatta D, Bañuelos C, Hernández-Nava E, Cuellar P, Orozco E. Epithelial Cells Expressing EhADH, An Entamoeba histolytica Adhesin, Exhibit Increased Tight Junction Proteins. Front Cell Infect Microbiol 2018; 8:340. [PMID: 30324093 PMCID: PMC6172307 DOI: 10.3389/fcimb.2018.00340] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 09/07/2018] [Indexed: 12/15/2022] Open
Abstract
In Entamoeba histolytica, the EhADH adhesin together with the EhCP112 cysteine protease, form a 124 kDa complex named EhCPADH. This complex participates in trophozoite adherence, phagocytosis and cytolysis of target cells. EhCPADH and EhCP112 are both involved on epithelium damage, by opening tight junctions (TJ) and reaching other intercellular junctions. EhADH is a scaffold protein belonging to the ALIX family that contains a Bro1 domain, expresses at plasma membrane, endosomes and cytoplasm of trophozoites, and is also secreted to the medium. Contribution of EhADH to TJ opening still remains unknown. In this paper, to elucidate the role of EhADH on epithelium injury, we followed two strategies: producing a recombinant protein (rEhADH) and transfecting the ehadh gene in MDCK cells. Results from the first strategy revealed that rEhADH reached the intercellular space of epithelial cells and co-localized with claudin-1 and occludin at TJ region; later, rEhADH was mainly internalized by clathrin-coated vesicles. In the second strategy, MDCK cells expressing EhADH (MDCK-EhADH) showed the adhesin at plasma membrane. In addition, MDCK-EHADH cells exhibited adhesive features, producing epithelial aggregation and adherence to erythrocytes, as described in trophozoites. Surprisingly, the adhesin expression produced an increase of claudin-1, occludin, ZO-1 and ZO-2 at TJ, and also the transepithelial electric resistance (TEER), which is a measure of TJ gate function. Moreover, MDCK-EhADH cells resulted more susceptible to trophozoites attack, as showed by TEER and cytopathic experiments. Overall, our results indicated that EhADH disturbed TJ from the extracellular space and also intracellularly, suggesting that EhADH affects by itself TJ proteins, and possibly synergizes the action of other parasite molecules during epithelial invasion.
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Affiliation(s)
- Abigail Betanzos
- Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico.,Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Dxinegueela Zanatta
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Cecilia Bañuelos
- Coordinación General de Programas de Posgrado Multidisciplinarios, Programa de Doctorado Transdisciplinario en Desarrollo Científico y Tecnológico para la Sociedad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Patricia Cuellar
- Centro Regional de Educación Superior, Universidad Autónoma de Guerrero, Chilpancingo, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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4
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Mil‐Homens D, Pinto SN, Matos RG, Arraiano C, Fialho AM. Burkholderia cenocepacia
K56‐2 trimeric autotransporter adhesin BcaA binds TNFR1 and contributes to induce airway inflammation. Cell Microbiol 2016; 19. [DOI: 10.1111/cmi.12677] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 09/22/2016] [Accepted: 09/24/2016] [Indexed: 01/10/2023]
Affiliation(s)
- Dalila Mil‐Homens
- Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico University of Lisbon Lisbon Portugal
| | - Sandra N. Pinto
- Centro de Química Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico University of Lisbon Lisbon Portugal
| | - Rute G. Matos
- Instituto de Tecnologia Química e Biológica – ITQB Universidade Nova de Lisboa Oeiras Portugal
| | - Cecília Arraiano
- Instituto de Tecnologia Química e Biológica – ITQB Universidade Nova de Lisboa Oeiras Portugal
| | - Arsenio M. Fialho
- Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico University of Lisbon Lisbon Portugal
- Department of Bioengineering, Instituto Superior Técnico University of Lisbon Lisbon Portugal
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5
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An Acinetobacter trimeric autotransporter adhesin reaped from cells exhibits its nonspecific stickiness via a highly stable 3D structure. Sci Rep 2016; 6:28020. [PMID: 27305955 PMCID: PMC4910087 DOI: 10.1038/srep28020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/27/2016] [Indexed: 11/24/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs), cell surface proteins of Gram-negative bacteria, mediate bacterial adhesion to host cells and extracellular matrix proteins. However, AtaA, a TAA in the nonpathogenic Acinetobacter sp. strain Tol 5, shows nonspecific, high adhesiveness to abiotic material surfaces as well as to biotic surfaces. AtaA is a homotrimer of polypeptides comprising 3,630 amino acids and forms long nanofibers; therefore, it is too large and structurally complex to be produced as a recombinant protein. In this study, we isolated AtaA’s passenger domain (AtaA PSD), which is translocated to the cell surface through the C-terminal transmembrane domain and exhibits biological functions, using a new method. We introduced a protease recognition site and reaped AtaA nanofibers 225 nm in length from the cell surface through proteolytic cleavage with a specific protease. Biochemical and biophysical analyses of the purified native AtaA PSD revealed that it has a stable structure under alkaline and acidic conditions. Temperatures above 80 °C, which disrupted AtaA’s higher-order structure but maintained the full-length AtaA polypeptide, inactivated AtaA’s nonspecific adhesiveness, suggesting that the stickiness of AtaA requires its 3D structure. This finding refutes the widespread but vague speculation that large unfolded polypeptides readily stick to various surfaces.
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6
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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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7
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Koiwai K, Hartmann MD, Linke D, Lupas AN, Hori K. Structural Basis for Toughness and Flexibility in the C-terminal Passenger Domain of an Acinetobacter Trimeric Autotransporter Adhesin. J Biol Chem 2015; 291:3705-24. [PMID: 26698633 DOI: 10.1074/jbc.m115.701698] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Indexed: 11/06/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs) on the cell surface of Gram-negative pathogens mediate bacterial adhesion to host cells and extracellular matrix proteins. However, AtaA, a TAA in the nonpathogenic Acinetobacter sp. strain Tol 5, shows nonspecific high adhesiveness to abiotic material surfaces as well as to biotic surfaces. It consists of a passenger domain secreted by the C-terminal transmembrane anchor domain (TM), and the passenger domain contains an N-terminal head, N-terminal stalk, C-terminal head (Chead), and C-terminal stalk (Cstalk). The Chead-Cstalk-TM fragment, which is conserved in many Acinetobacter TAAs, has by itself the head-stalk-anchor architecture of a complete TAA. Here, we show the crystal structure of the Chead-Cstalk fragment, AtaA_C-terminal passenger domain (CPSD), providing the first view of several conserved TAA domains. The YadA-like head (Ylhead) of the fragment is capped by a unique structure (headCap), composed of three β-hairpins and a connector motif; it also contains a head insert motif (HIM1) before its last inner β-strand. The headCap, Ylhead, and HIM1 integrally form a stable Chead structure. Some of the major domains of the CPSD fragment are inherently flexible and provide bending sites for the fiber between segments whose toughness is ensured by topological chain exchange and hydrophobic core formation inside the trimer. Thus, although adherence assays using in-frame deletion mutants revealed that the characteristic adhesive sites of AtaA reside in its N-terminal part, the flexibility and toughness of the CPSD part provide the resilience that enables the adhesive properties of the full-length fiber across a wide range of conditions.
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Affiliation(s)
- Kotaro Koiwai
- From the Department of Biotechnology, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan, the Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan
| | - Marcus D Hartmann
- the Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany, and
| | - Dirk Linke
- the Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany, and the Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Andrei N Lupas
- the Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany, and
| | - Katsutoshi Hori
- From the Department of Biotechnology, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan,
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8
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Qin W, Wang L, Lei L. New findings on the function and potential applications of the trimeric autotransporter adhesin. Antonie van Leeuwenhoek 2015; 108:1-14. [PMID: 26014492 DOI: 10.1007/s10482-015-0477-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 05/08/2015] [Indexed: 11/27/2022]
Abstract
Trimeric autotransporter adhesins (TAAs) are located on the surface of many pathogenic Gram-negative bacteria. TAAs belong to the autotransporter protein family and consist of three identical monomers. These obligate homotrimeric proteins are secreted through the bacterial type Vc secretion system and share a common molecular organization that each monomer consists of a N-terminal "passenger" domain and a C-terminal translocation domain. TAAs are important virulence factors that are involved in bacterial life cycle and participate in mediating infection, invasion, dissemination and evasion of host immune responses. TAAs have also proved to be useful for many applications, such as vaccines and disease biomarkers. We here mainly focused on new findings on bio-function and application of TAAs in addition to their common structure and secretion mechanisms.
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Affiliation(s)
- Wanhai Qin
- College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, China,
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9
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Bozza G, Capitani M, Montanari P, Benucci B, Biancucci M, Nardi-Dei V, Caproni E, Barrile R, Picciani B, Savino S, Aricò B, Rappuoli R, Pizza M, Luini A, Sallese M, Merola M. Role of ARF6, Rab11 and external Hsp90 in the trafficking and recycling of recombinant-soluble Neisseria meningitidis adhesin A (rNadA) in human epithelial cells. PLoS One 2014; 9:e110047. [PMID: 25347845 PMCID: PMC4210143 DOI: 10.1371/journal.pone.0110047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 09/16/2014] [Indexed: 01/02/2023] Open
Abstract
Neisseria meningitidisadhesin A (NadA) is a meningococcus surface protein thought to assist in the adhesion of the bacterium to host cells. We have previously shown that NadA also promotes bacterial internalization in a heterologous expression system. Here we have used the soluble recombinant NadA (rNadA) lacking the membrane anchor region to characterize its internalization route in Chang epithelial cells. Added to the culture medium, rNadA internalizes through a PI3K-dependent endocytosis process not mediated by the canonical clathrin or caveolin scaffolds, but instead follows an ARF6-regulated recycling pathway previously described for MHC-I. The intracellular pool of rNadA reaches a steady state level within one hour of incubation and colocalizes in endocytic vesicles with MHC-I and with the extracellularly labeled chaperone Hsp90. Treatment with membrane permeated and impermeable Hsp90 inhibitors 17-AAG and FITC-GA respectively, lead to intracellular accumulation of rNadA, strongly suggesting that the extracellular secreted pool of the chaperone is involved in rNadA intracellular trafficking. A significant number of intracellular vesicles containing rNadA recruit Rab11, a small GTPase associated to recycling endosomes, but do not contain transferrin receptor (TfR). Interestingly, cell treatment with Hsp90 inhibitors, including the membrane-impermeable FITC-GA, abolished Rab11-rNadA colocalization but do not interfere with Rab11-TfR colocalization. Collectively, these results are consistent with a model whereby rNadA internalizes into human epithelial cells hijacking the recycling endosome pathway and recycle back to the surface of the cell via an ARF6-dependent, Rab11 associated and Hsp90-regulated mechanism. The present study addresses for the first time a meningoccoccal adhesin mechanism of endocytosis and suggests a possible entry pathway engaged by N. meningitidis in primary infection of human epithelial cells.
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Affiliation(s)
| | - Mirco Capitani
- Unit of Genomic Approaches to Membrane Traffic, Fondazione Mario Negri Sud, S. Maria Imbaro (CH), Italy
| | | | | | | | | | | | | | - Benedetta Picciani
- Unit of Genomic Approaches to Membrane Traffic, Fondazione Mario Negri Sud, S. Maria Imbaro (CH), Italy
| | | | | | | | | | - Alberto Luini
- Institute of Protein Biochemistry, CNR, Naples, Italy
| | - Michele Sallese
- Unit of Genomic Approaches to Membrane Traffic, Fondazione Mario Negri Sud, S. Maria Imbaro (CH), Italy
- * E-mail: (MS); (MM)
| | - Marcello Merola
- Novartis Vaccines, Siena, Italy
- Department of Biology, University of Naples “Federico II”, Naples, Italy
- * E-mail: (MS); (MM)
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10
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Characterization of BCAM0224, a multifunctional trimeric autotransporter from the human pathogen Burkholderia cenocepacia. J Bacteriol 2014; 196:1968-79. [PMID: 24659767 DOI: 10.1128/jb.00061-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the trimeric autotransporter adhesin (TAA) family play a crucial role in adhesion of Gram-negative pathogens to host cells. Moreover, these proteins are multifunctional virulence factors involved in several other biological traits, including invasion into host cells and evasion of the host immune system. In cystic fibrosis epidemic Burkholderia cenocepacia strain J2315, we identified a unique TAA (BCAM0224)-encoding gene, previously described as being implicated in virulence. Here, we characterized this multifunctional protein, trying to establish its role in B. cenocepacia pathogenicity. We show that BCAM0224 occurs on the bacterial surface and adopts a trimeric conformation. Furthermore, we demonstrated that BCAM0224 is needed for earlier stages of biofilm formation and is required for swarming motility. In addition, BCAM0224 plays an important role in evasion of the human innate immune system, providing resistance against the bactericidal activity of serum via the complement classical pathway. Finally, BCAM0224 mediates bacterial adhesion to and invasion of cultured human bronchial epithelial cells. Together, these data reveal the high versatility of the BCAM0224 protein as a virulence factor in the pathogenic bacterium B. cenocepacia.
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11
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Ruiz-Ranwez V, Posadas DM, Estein SM, Abdian PL, Martin FA, Zorreguieta A. The BtaF trimeric autotransporter of Brucella suis is involved in attachment to various surfaces, resistance to serum and virulence. PLoS One 2013; 8:e79770. [PMID: 24236157 PMCID: PMC3827427 DOI: 10.1371/journal.pone.0079770] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/02/2013] [Indexed: 02/02/2023] Open
Abstract
The adhesion of bacterial pathogens to host cells is an event that determines infection, and ultimately invasion and intracellular multiplication. Several evidences have recently shown that this rule is also truth for the intracellular pathogen Brucella. Brucella suis displays the unipolar BmaC and BtaE adhesins, which belong to the monomeric and trimeric autotransporter (TA) families, respectively. It was previously shown that these adhesins are involved in bacterial adhesion to host cells and components of the extracellular matrix (ECM). In this work we describe the role of a new member of the TA family of B. suis (named BtaF) in the adhesive properties of the bacterial surface. BtaF conferred the bacteria that carried it a promiscuous adhesiveness to various ECM components and the ability to attach to an abiotic surface. Furthermore, BtaF was found to participate in bacterial adhesion to epithelial cells and was required for full virulence in mice. Similar to BmaC and BtaE, the BtaF adhesin was expressed in a small subpopulation of bacteria, and in all cases, it was detected at the new pole generated after cell division. Interestingly, BtaF was also implicated in the resistance of B. suis to porcine serum. Our findings emphasize the impact of TAs in the Brucella lifecycle.
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12
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Internalization and trafficking of nontypeable Haemophilus influenzae in human respiratory epithelial cells and roles of IgA1 proteases for optimal invasion and persistence. Infect Immun 2013; 82:433-44. [PMID: 24218477 DOI: 10.1128/iai.00864-13] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHI) is a leading cause of opportunistic infections of the respiratory tract in children and adults. Although considered an extracellular pathogen, NTHI has been observed repeatedly within and between cells of the human respiratory tract, and these observations have been correlated to symptomatic infection. These findings are intriguing in light of the knowledge that NTHI persists in the respiratory tract despite antibiotic therapy and the development of bactericidal antibodies. We hypothesized that intracellular NTHI avoids, escapes, or neutralizes the endolysosomal pathway and persists within human respiratory epithelial cells and that human IgA1 proteases are required for optimal internalization and persistence of NTHI. Virtually all strains encode a human IgA1 protease gene, igaA, and we previously characterized a novel human IgA1 protease gene, igaB, that is associated with disease-causing strains and is homologous to the IgA1 protease that is unique to pathogenic Neisseria spp. Here, we show that NTHI invades human bronchial epithelial cells in vitro in a lipid raft-independent manner, is subsequently trafficked via the endolysosomal pathway, and is killed in lysosomes after variable durations of persistence. IgaA is required for optimal invasion. IgaB appears to play little or no role in adherence or invasion but is required for optimal intracellular persistence of NTHI. IgaB cleaves lysosome-associated membrane protein 1 (LAMP1) at pHs characteristic of the plasma membrane, early endosome, late endosome, and lysosome. However, neither IgA1 protease inhibits acidification of intracellular vesicles containing NTHI. NTHI IgA1 proteases play important but different roles in NTHI invasion and trafficking in respiratory epithelial cells.
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13
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El-Kirat-Chatel S, Mil-Homens D, Beaussart A, Fialho AM, Dufrêne YF. Single-molecule atomic force microscopy unravels the binding mechanism of aBurkholderia cenocepaciatrimeric autotransporter adhesin. Mol Microbiol 2013; 89:649-59. [DOI: 10.1111/mmi.12301] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Sofiane El-Kirat-Chatel
- Université catholique de Louvain; Institute of Life Sciences; Croix du Sud, 1, bte L7.04.01.; B-1348; Louvain-la-Neuve; Belgium
| | - Dalila Mil-Homens
- IBB-Institute for Biotechnology and Bioengineering; Instituto Superior Técnico; Lisbon; 1049-001; Portugal
| | - Audrey Beaussart
- Université catholique de Louvain; Institute of Life Sciences; Croix du Sud, 1, bte L7.04.01.; B-1348; Louvain-la-Neuve; Belgium
| | | | - Yves F. Dufrêne
- Université catholique de Louvain; Institute of Life Sciences; Croix du Sud, 1, bte L7.04.01.; B-1348; Louvain-la-Neuve; Belgium
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14
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BtaE, an adhesin that belongs to the trimeric autotransporter family, is required for full virulence and defines a specific adhesive pole of Brucella suis. Infect Immun 2013; 81:996-1007. [PMID: 23319562 DOI: 10.1128/iai.01241-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Brucella is responsible for brucellosis, one of the most common zoonoses worldwide that causes important economic losses in several countries. Increasing evidence indicates that adhesion of Brucella spp. to host cells is an important step to establish infection. We have previously shown that the BmaC unipolar monomeric autotransporter mediates the binding of Brucella suis to host cells through cell-associated fibronectin. Our genome analysis shows that the B. suis genome encodes several additional potential adhesins. In this work, we characterized a predicted trimeric autotransporter that we named BtaE. By expressing btaE in a nonadherent Escherichia coli strain and by phenotypic characterization of a B. suis ΔbtaE mutant, we showed that BtaE is involved in the binding of B. suis to hyaluronic acid. The B. suis ΔbtaE mutant exhibited a reduction in the adhesion to HeLa and A549 epithelial cells compared with the wild-type strain, and it was outcompeted by the wild-type strain in the binding to HeLa cells. The knockout btaE mutant showed an attenuated phenotype in the mouse model, indicating that BtaE is required for full virulence. BtaE was immunodetected on the bacterial surface at one cell pole. Using old and new pole markers, we observed that both the BmaC and BtaE adhesins are consistently associated with the new cell pole, suggesting that, in Brucella, the new pole is functionally differentiated for adhesion. This is consistent with the inherent polarization of this bacterium, and its role in the invasion process.
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15
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Ishikawa M, Nakatani H, Hori K. AtaA, a new member of the trimeric autotransporter adhesins from Acinetobacter sp. Tol 5 mediating high adhesiveness to various abiotic surfaces. PLoS One 2012; 7:e48830. [PMID: 23155410 PMCID: PMC3498257 DOI: 10.1371/journal.pone.0048830] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Accepted: 10/05/2012] [Indexed: 11/19/2022] Open
Abstract
Acinetobacter sp. Tol 5 exhibits an autoagglutinating nature and noteworthy adhesiveness to various abiotic surfaces from hydrophobic plastics to hydrophilic glass and stainless steel. Although previous studies have suggested that bacterionanofibers on Tol 5 cells are involved in the adhesive phenotype of Tol 5, the fiber that directly mediates Tol 5 adhesion has remained unknown. Here, we present a new member of trimeric autotransporter adhesins designated AtaA, which we discovered by analyzing a less adhesive mutant of Tol 5, T1, obtained by transposon mutagenesis. AtaA forms thinner and shorter nanofibers than fimbriae on Tol 5 cells. We performed target disruption of ataA by allelic marker exchange, and the resulting ΔataA strain was complemented with ataA on the Escherichia coli-Acinetobacter shuttle vector, which was newly constructed. These results proved that AtaA is essential for Tol 5's autoagglutinating nature and high adhesiveness to surfaces of various materials. In addition, the adhesiveness to solid surfaces mediated by AtaA is notably higher than that mediated by YadA of Yersinia enterocolitica WA-314. Moreover, and importantly, these characteristics can be conferred to the non-adhesive, non-agglutinating bacterium Acinetobacter sp. ADP1 in trans by transformation with ataA, with expected applications to microbial immobilization.
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Affiliation(s)
| | | | - Katsutoshi Hori
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Japan
- * E-mail:
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16
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Costa-Hurtado M, Ballester M, Galofré-Milà N, Darji A, Aragon V. VtaA8 and VtaA9 from Haemophilus parasuis delay phagocytosis by alveolar macrophages. Vet Res 2012; 43:57. [PMID: 22839779 PMCID: PMC3462726 DOI: 10.1186/1297-9716-43-57] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 06/20/2012] [Indexed: 12/02/2022] Open
Abstract
Haemophilus parasuis, a member of the family Pasteurellaceae, is a common inhabitant of the upper respiratory tract of healthy pigs and the etiological agent of Glässer’s disease. As other virulent Pasteurellaceae, H. parasuis can prevent phagocytosis, but the bacterial factors involved in this virulence mechanism are not known. In order to identify genes involved in phagocytosis resistance, we constructed a genomic library of the highly virulent reference strain Nagasaki and clones were selected by increased survival after incubation with porcine alveolar macrophages (PAM). Two clones containing two virulent-associated trimeric autotransporter (VtaA) genes, vtaA8 and vtaA9, respectively, were selected by this method. A reduction in the interaction of the two clones with the macrophages was detected by flow cytometry. Monoclonal antibodies were produced and used to demonstrate the presence of these proteins on the bacterial surface of the corresponding clone, and on the H. parasuis phagocytosis-resistant strain PC4-6P. The effect of VtaA8 and VtaA9 in the trafficking of the bacteria through the endocytic pathway was examined by fluorescence microscopy and a delay was detected in the localization of the vtaA8 and vtaA9 clones in acidic compartments. These results are compatible with a partial inhibition of the routing of the bacteria via the degradative phagosome. Finally, antibodies against a common epitope in VtaA8 and VtaA9 were opsonic and promoted phagocytosis of the phagocytosis-resistant strain PC4-6P by PAM. Taken together, these results indicate that VtaA8 and VtaA9 are surface proteins that play a role in phagocytosis resistance of H. parasuis.
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Affiliation(s)
- Mar Costa-Hurtado
- Centre de Recerca en Sanitat Animal, (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
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17
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Mil-Homens D, Fialho AM. A BCAM0223 mutant of Burkholderia cenocepacia is deficient in hemagglutination, serum resistance, adhesion to epithelial cells and virulence. PLoS One 2012; 7:e41747. [PMID: 22848588 PMCID: PMC3404963 DOI: 10.1371/journal.pone.0041747] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 06/25/2012] [Indexed: 11/19/2022] Open
Abstract
Burkholderia cepacia complex (Bcc) bacteria are a problematic group of microorganisms causing severe infections in patients with Cystic Fibrosis. In early stages of infection, Bcc bacteria must be able to adhere to and colonize the respiratory epithelium. Although this is not fully understood, this primary stage of infection is believed to be in part mediated by a specific type of adhesins, named trimeric autotransporter adhesins (TAAs). These homotrimeric proteins exist on the surface of many gram negative pathogens and often mediate a number of critical functions, including biofilm formation, serum resistance and adherence to an invasion of host cells. We have previously identified in the genome of the epidemic clinical isolate B. cenocepacia J2315, a novel cluster of genes putatively encoding three TAAs (BCAM0219, BCAM0223 and BCAM0224). In this study, the genomic organization of the TAA cluster has been determined. To further address the direct role of the putative TAA BCAM0223 in B. cenocepacia pathogenicity, an isogenic mutant was constructed via insertional inactivation. The BCAM0223::Tp mutant is deficient in hemagglutination, affected in adherence to vitronectin and in biofilm formation and showed attenuated virulence in the Galleria mellonella model of infection. Moreover, the BCAM0223::Tp mutant also showed a significant reduction in its resistance to human serum as well as in adherence, but not in invasion of, cultured human bronchial epithelial cells. Altogether these results demonstrate that the BCAM0223 protein is a multifunctional virulence factor that may contribute to the pathogenicity of B. cenocepacia.
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Affiliation(s)
- Dalila Mil-Homens
- IBB-Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
| | - Arsenio M. Fialho
- IBB-Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Technical University of Lisbon, Lisbon, Portugal
- * E-mail:
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18
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Strouts FR, Power P, Croucher NJ, Corton N, van Tonder A, Quail MA, Langford PR, Hudson MJ, Parkhill J, Kroll JS, Bentley SD. Lineage-specific virulence determinants of Haemophilus influenzae biogroup aegyptius. Emerg Infect Dis 2012; 18:449-57. [PMID: 22377449 PMCID: PMC3309571 DOI: 10.3201/eid1803.110728] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Novel adhesions, including trimeric autotransporters, might contribute to virulence. An emergent clone of Haemophilus influenzae biogroup aegyptius (Hae) is responsible for outbreaks of Brazilian purpuric fever (BPF). First recorded in Brazil in 1984, the so-called BPF clone of Hae caused a fulminant disease that started with conjunctivitis but developed into septicemic shock; mortality rates were as high as 70%. To identify virulence determinants, we conducted a pan-genomic analysis. Sequencing of the genomes of the BPF clone strain F3031 and a noninvasive conjunctivitis strain, F3047, and comparison of these sequences with 5 other complete H. influenzae genomes showed that >77% of the F3031 genome is shared among all H. influenzae strains. Delineation of the Hae accessory genome enabled characterization of 163 predicted protein-coding genes; identified differences in established autotransporter adhesins; and revealed a suite of novel adhesins unique to Hae, including novel trimeric autotransporter adhesins and 4 new fimbrial operons. These novel adhesins might play a critical role in host–pathogen interactions.
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Affiliation(s)
- Fiona R Strouts
- Imperial College London, Medicine, St Mary’s Hospital campus, Norfolk Place, London W2 1PG, UK
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19
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Evaluation of adhesiveness of Acinetobacter sp. Tol 5 to abiotic surfaces. J Biosci Bioeng 2012; 113:719-25. [PMID: 22321378 DOI: 10.1016/j.jbiosc.2012.01.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/10/2012] [Accepted: 01/16/2012] [Indexed: 11/20/2022]
Abstract
The toluene-degrading bacterium Acinetobacter sp. Tol 5 shows a highly adhesive and autoagglutinating nature through cell surface nanofibers. In the present study, various aspects of the adhesiveness of Tol 5 cells were evaluated, namely, the association with biofilm formation, the specificity, and the effects of additives. During growth, Tol 5 and Pseudomonas aeruginosa PAO1 cells showed high capacities to form biofilms. However, resting PAO1 cells barely adhered to a polystyrene (PS) surface, while a large number of resting Tol 5 cells rapidly adhered. This implies that Tol 5 cells are intrinsically adhesive and that their initial attachment ability is quite high and distinguishable from their ability to form biofilm. This high adhesiveness of Tol 5 cells was considered to be nonspecific because the cells adhered to various material surfaces from hydrophobic plastic surfaces to hydrophilic glass and metal surfaces. However, Tol 5 cells were found not to be adhesive to Escherichia coli cells. Although Tol 5 cells were capable of interspecies interaction and coagglutination with E. coli cells, at the surface of cell clumps, E. coli cells localized, suggesting that they disturbed autoagglutination of Tol 5 cells. Tol 5 has a hydrophobic cell surface. However, the addition of nonionic surfactant Triton X-100 and bovine serum albumin increased the adhesion of Tol 5 cells to a PS surface, in contrast to previous reports of hydrophobic bacteria. The results highlighted the interesting features of adhesiveness of Tol 5 cells.
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20
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Montanari P, Bozza G, Capecchi B, Caproni E, Barrile R, Norais N, Capitani M, Sallese M, Cecchini P, Ciucchi L, Gao Z, Rappuoli R, Pizza M, Aricò B, Merola M. Human heat shock protein (Hsp) 90 interferes with Neisseria meningitidis adhesin A (NadA)-mediated adhesion and invasion. Cell Microbiol 2011; 14:368-85. [DOI: 10.1111/j.1462-5822.2011.01722.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Mil-Homens D, Fialho AM. Trimeric autotransporter adhesins in members of the Burkholderia cepacia complex: a multifunctional family of proteins implicated in virulence. Front Cell Infect Microbiol 2011; 1:13. [PMID: 22919579 PMCID: PMC3417366 DOI: 10.3389/fcimb.2011.00013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 11/15/2011] [Indexed: 11/13/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs) are multimeric surface proteins exclusively found in bacteria. They are involved in various biological traits of pathogenic Gram-negative bacteria including adherence, biofilm formation, invasion, survival within eukaryotic cells, serum resistance, and cytotoxicity. TAAs have a modular architecture composed by a conserved membrane-anchored C-terminal domain and a variable number of stalk and head domains. In this study, a bioinformatic approach has been used to analyze the distribution and architecture of TAAs among Burkholderia cepacia complex (Bcc) genomes. Fifteen genomes were probed revealing a total of 74 encoding sequences. Compared with other bacterial species, the Bcc genomes contain a large number of TAAs (two genes to up to eight genes, such as in B. cenocepacia). Phylogenetic analysis showed that the TAAs grouped into at least eight distinct clusters. TAAs with serine-rich repeats are clearly well separated from others, thereby representing a different evolutionary lineage. Comparative gene mapping across Bcc genomes reveals that TAA genes are inserted within conserved synteny blocks. We further focused our analysis on the epidemic strain B. cenocepacia J2315 in which seven TAAs were annotated. Among these, three TAA-encoding genes (BCAM019, BCAM0223, and BCAM0224) are organized into a cluster and are candidates for multifunctional virulence factors. Here we review the current insights into the functional role of BCAM0224 as a model locus.
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Affiliation(s)
- Dalila Mil-Homens
- Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior Técnico Lisbon, Portugal
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22
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Kaiser PO, Linke D, Schwarz H, Leo JC, Kempf VAJ. Analysis of the BadA stalk from Bartonella henselae reveals domain-specific and domain-overlapping functions in the host cell infection process. Cell Microbiol 2011; 14:198-209. [PMID: 21981119 DOI: 10.1111/j.1462-5822.2011.01711.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human pathogenic Bartonella henselae cause cat scratch disease and vasculoproliferative disorders. An important pathogenicity factor of B. henselae is the trimeric autotransporter adhesin Bartonella adhesin A (BadA) which is modularly constructed and consists of a head, a long and repetitive neck-stalk module with 22 repetitive neck/stalk repeats and a membrane anchor. The BadA head is crucial for bacterial adherence to host cells, binding to several extracellular matrix proteins and for the induction of vascular endothelial growth factor (VEGF) secretion. Here, we analysed the biological role of the BadA stalk in the infection process in greater detail. For this purpose, BadA head-bearing and headless deletion mutants with different lengths (containing one or four neck/stalk repeats in the neck-stalk module) were produced and functionally analysed for their ability to bind to fibronectin, collagen and endothelial cells and to induce VEGF secretion. Whereas a head-bearing short version (one neck/stalk element) of BadA lacks exclusively fibronectin binding, a substantially truncated headless BadA mutant was deficient for all of these biological functions. The expression of a longer headless BadA mutant (four neck/stalk repeats) restored fibronectin and collagen binding, adherence to host cells and the induction of VEGF secretion. Our data suggest that (i) the stalk of BadA is exclusively responsible for fibronectin binding and that (ii) both the head and stalk of BadA mediate adherence to collagen and host cells and the induction of VEGF secretion. This indicates overlapping functions of the BadA head and stalk.
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Affiliation(s)
- Patrick O Kaiser
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Universitätsklinikum, Goethe-Universität, Paul Ehrlich Str.40, 60596 Frankfurt am Main, Germany
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23
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A naturally occurring single-residue mutation in the translocator domain of Neisseria meningitidis NhhA affects trimerization, surface localization, and adhesive capabilities. Infect Immun 2011; 79:4308-21. [PMID: 21844231 DOI: 10.1128/iai.00198-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neisseria meningitidis NhhA (Neisseria hia/hsf homologue A) is an oligomeric outer membrane protein belonging to the family of trimeric autotransporter adhesins. NhhA mediates the interaction of N. meningitidis with human epithelial cells and components of the extracellular matrix. The recombinant protein is able to induce bactericidal antibodies and hence has also been considered a potential vaccine candidate. In this study, we analyzed the production of NhhA in a large panel of N. meningitidis strains belonging to different serogroups and clonal complexes. We found that trimeric NhhA was produced at different levels by the various strains tested. In some strains belonging to the clonal complex ST41/44, the protein is detectable only as a monomer. Sequencing of the nhhA gene and generation of complementing strains in different genetic backgrounds have proved that a single mutation (Gly to Asp) in the translocator domain affected both trimerization and surface localization of NhhA. In vitro infection assays showed that this mutation impairs meningococcal NhhA-mediated adhesion, suggesting that strains carrying the mutation may rely on different strategies or molecules to mediate interaction with host cells. Finally, we demonstrated that N. meningitidis ST41/44 strains producing the mutated form did not induce killing mediated by NhhA-specific bactericidal antibodies. Our data help to elucidate the secretion mechanisms of trimeric autotransporters and to understand the contribution of NhhA in the evolutionary process of host-Neisseria interactions. Also, they might have important implications for the evaluation of NhhA as a vaccine candidate.
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Structures and functions of autotransporter proteins in microbial pathogens. Int J Med Microbiol 2011; 301:461-8. [DOI: 10.1016/j.ijmm.2011.03.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 03/22/2011] [Accepted: 03/27/2011] [Indexed: 12/23/2022] Open
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25
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Immunogenicity and protection against Haemophilus parasuis infection after vaccination with recombinant virulence associated trimeric autotransporters (VtaA). Vaccine 2011; 29:2797-802. [DOI: 10.1016/j.vaccine.2011.01.105] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 01/21/2011] [Accepted: 01/30/2011] [Indexed: 11/22/2022]
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26
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Mapping of the Neisseria meningitidis NadA cell-binding site: relevance of predicted {alpha}-helices in the NH2-terminal and dimeric coiled-coil regions. J Bacteriol 2010; 193:107-15. [PMID: 20971901 DOI: 10.1128/jb.00430-10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
NadA is a trimeric autotransporter protein of Neisseria meningitidis belonging to the group of oligomeric coiled-coil adhesins. It is implicated in the colonization of the human upper respiratory tract by hypervirulent serogroup B N. meningitidis strains and is part of a multiantigen anti-serogroup B vaccine. Structure prediction indicates that NadA is made by a COOH-terminal membrane anchor (also necessary for autotranslocation to the bacterial surface), an intermediate elongated coiled-coil-rich stalk, and an NH(2)-terminal region involved in cell interaction. Electron microscopy analysis and structure prediction suggest that the apical region of NadA forms a compact and globular domain. Deletion studies proved that the NH(2)-terminal sequence (residues 24 to 87) is necessary for cell adhesion. In this study, to better define the NadA cell binding site, we exploited (i) a panel of NadA mutants lacking sequences along the coiled-coil stalk and (ii) several oligoclonal rabbit antibodies, and their relative Fab fragments, directed to linear epitopes distributed along the NadA ectodomain. We identified two critical regions for the NadA-cell receptor interaction with Chang cells: the NH(2) globular head domain and the NH(2) dimeric intrachain coiled-coil α-helices stemming from the stalk. This raises the importance of different modules within the predicted NadA structure. The identification of linear epitopes involved in receptor binding that are able to induce interfering antibodies reinforces the importance of NadA as a vaccine antigen.
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27
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Pizarro-Cerdá J, Bonazzi M, Cossart P. Clathrin-mediated endocytosis: what works for small, also works for big. Bioessays 2010; 32:496-504. [PMID: 20486136 DOI: 10.1002/bies.200900172] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Clathrin and the endocytosis machinery has recently been described as being required in mammalian cells for the internalization of large particles including pathogenic bacteria, fungi, and large viruses. These apparently unexpected observations, within the framework of the classical mechanisms for the formation of clathrin-coated vesicles, are now considered as examples of a new non-classical function of clathrin, which can promote the internalization of membrane domains associated to planar clathrin lattices. The role of actin downstream of clathrin seems to be critical for this still poorly characterized process. The historical frontier between endocytosis and phagocytosis is vanishing in the light of this new role for clathrin.
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Affiliation(s)
- Javier Pizarro-Cerdá
- Département de Biologie Cellulaire et Infection, Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris, France
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28
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Kline KA, Fälker S, Dahlberg S, Normark S, Henriques-Normark B. Bacterial adhesins in host-microbe interactions. Cell Host Microbe 2009; 5:580-92. [PMID: 19527885 DOI: 10.1016/j.chom.2009.05.011] [Citation(s) in RCA: 406] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 05/23/2009] [Accepted: 05/27/2009] [Indexed: 02/09/2023]
Abstract
Most commensal and pathogenic bacteria interacting with eukaryotic hosts express adhesive molecules on their surfaces that promote interaction with host cell receptors or with soluble macromolecules. Even though bacterial attachment to epithelial cells may be beneficial for bacterial colonization, adhesion may come at a cost because bacterial attachment to immune cells can facilitate phagocytosis and clearing. Many pathogenic bacteria have solved this dilemma by producing an antiphagocytic surface layer usually consisting of polysaccharide and by expressing their adhesins on polymeric structures that extend out from the cell surface. In this review, we will focus on the interaction between bacterial adhesins and the host, with an emphasis on pilus-like structures.
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Affiliation(s)
- Kimberly A Kline
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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