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Yang G, Yang L, Zhou X. Inhibition of bacterial swimming by heparin binding of flagellin FliC from Escherichia coli strain Nissle 1917. Arch Microbiol 2023; 205:286. [PMID: 37452842 DOI: 10.1007/s00203-023-03622-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/18/2023]
Abstract
Escherichia coli Nissle1917 (EcN) is a non-pathogenic probiotic strain widely used to maintain gut health, treat gastrointestinal disorders, and modulate the gut microbiome due to its anti-inflammatory and competitive exclusion effects against pathogenic bacteria. Heparin, abundant on intestinal mucosal surfaces, is a highly sulfated glycosaminoglycan primarily produced by mast cells. Currently, the interaction between EcN surface protein and heparin has remained elusive. In this study, the flagellin FliC responsible for EcN's movement was separated and characterized as a heparin binding protein by mass spectrometry (MS) analysis. The recombinant FliC protein, expressed by plasmid pET28a( +)-fliC, was further prepared to confirm the interaction between FliC and heparin. The results showed that heparin-Sepharose's ability to bind FliC was 48-fold higher than its ability to bind the negative control, bovine serum albumin (BSA). Neither the knockout of gene fliC nor the addition of heparin affects the growth of EcN, but both significantly inhibit the swimming of EcN. Adding 10 mg/ml heparin reduced the swimming diameter of the wild type and the complemented strain to 29-41% of the original, but that did not affect the swimming ability of the knockout strains. These results demonstrate that heparin interacts with EcN flagellin FliC and inhibits bacteria swimming. Exploring this interaction could improve our understanding of the relationship between hosts and microorganisms and provide a potential basis for disease treatment.
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Affiliation(s)
- Guixia Yang
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, 230009, Anhui, China
| | - Lingkang Yang
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, 230009, Anhui, China
| | - Xianxuan Zhou
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, 230009, Anhui, China.
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2
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Jahnke R, Matthiesen S, Zaeck LM, Finke S, Knittler MR. Chlamydia trachomatis Cell-to-Cell Spread through Tunneling Nanotubes. Microbiol Spectr 2022; 10:e0281722. [PMID: 36219107 PMCID: PMC9769577 DOI: 10.1128/spectrum.02817-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/16/2022] [Indexed: 01/09/2023] Open
Abstract
Tunneling nanotubes (TNTs) are transient cellular connections that consist of dynamic membrane protrusions. They play an important role in cell-to-cell communication and mediate the intercellular exchanges of molecules and organelles. TNTs can form between different cell types and may contribute to the spread of pathogens by serving as cytoplasmic corridors. We demonstrate that Chlamydia (C.) trachomatis-infected human embryonic kidney (HEK) 293 cells and other cells form TNT-like structures through which reticulate bodies (RBs) pass into uninfected cells. Observed TNTs have a life span of 1 to 5 h and contain microtubules, which are essential for chlamydial transfer. They can bridge distances of up to 50 μm between connecting neighboring cells. Consistent with the biological role for TNTs, we show that C. trachomatis spread also occurs under conditions in which the extracellular route of chlamydial entry into host cells is blocked. Based on our findings, we propose that TNTs play a critical role in the direct, cell-to-cell transmission of chlamydia. IMPORTANCE Intracellular bacterial pathogens often undergo a life cycle in which they parasitize infected host cells in membranous vacuoles. Two pathways have been described by which chlamydia can exit infected host cells: lytic cell destruction or exit via extrusion formation. Whether direct, cell-to-cell contact may also play a role in the spread of infection is unknown. Tunneling nanotubes (TNTs) interconnect the cytoplasm of adjacent cells to mediate efficient communication and the exchange of material between them. We used Chlamydia trachomatis and immortalized cells to analyze whether TNTs mediate bacterial transmission from an infected donor to uninfected acceptor cells. We show that chlamydia-infected cells build TNTs through which the intracellular reticulate bodies (RBs) of the chlamydia can pass into uninfected neighboring cells. Our study contributes to the understanding of the function of TNTs in the cell-to-cell transmission of intracellular pathogens and provides new insights into the strategies by which chlamydia spreads among multicellular tissues.
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Affiliation(s)
- Rico Jahnke
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
| | - Svea Matthiesen
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
| | - Luca M. Zaeck
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
| | - Stefan Finke
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
| | - Michael R. Knittler
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
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3
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Coxiella burnetii-Infected NK Cells Release Infectious Bacteria by Degranulation. Infect Immun 2020; 88:IAI.00172-20. [PMID: 32817330 DOI: 10.1128/iai.00172-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 08/10/2020] [Indexed: 01/24/2023] Open
Abstract
Natural killer (NK) cells are critically involved in the early immune response against various intracellular pathogens, including Coxiella burnetii and Chlamydia psittaci Chlamydia-infected NK cells functionally mature, induce cellular immunity, and protect themselves by killing the bacteria in secreted granules. Here, we report that infected NK cells do not allow intracellular multiday growth of Coxiella, as is usually observed in other host cell types. C. burnetii-infected NK cells display maturation and gamma interferon (IFN-γ) secretion, as well as the release of Coxiella-containing lytic granules. Thus, NK cells possess a potent program to restrain and expel different types of invading bacteria via degranulation. Strikingly, though, in contrast to Chlamydia, expulsed Coxiella organisms largely retain their infectivity and, hence, escape the cell-autonomous self-defense mechanism in NK cells.
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4
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Haridas V, Ranjbar S, Vorobjev IA, Goldfeld AE, Barteneva NS. Imaging flow cytometry analysis of intracellular pathogens. Methods 2017; 112:91-104. [PMID: 27642004 PMCID: PMC5857943 DOI: 10.1016/j.ymeth.2016.09.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/15/2016] [Accepted: 09/15/2016] [Indexed: 01/09/2023] Open
Abstract
Imaging flow cytometry has been applied to address questions in infection biology, in particular, infections induced by intracellular pathogens. This methodology, which utilizes specialized analytic software makes it possible to analyze hundreds of quantified features for hundreds of thousands of individual cellular or subcellular events in a single experiment. Imaging flow cytometry analysis of host cell-pathogen interaction can thus quantitatively addresses a variety of biological questions related to intracellular infection, including cell counting, internalization score, and subcellular patterns of co-localization. Here, we provide an overview of recent achievements in the use of fluorescently labeled prokaryotic or eukaryotic pathogens in human cellular infections in analysis of host-pathogen interactions. Specifically, we give examples of Imagestream-based analysis of cell lines infected with Toxoplasma gondii or Mycobacterium tuberculosis. Furthermore, we illustrate the capabilities of imaging flow cytometry using a combination of standard IDEAS™ software and the more recently developed Feature Finder algorithm, which is capable of identifying statistically significant differences between researcher-defined image galleries. We argue that the combination of imaging flow cytometry with these software platforms provides a powerful new approach to understanding host control of intracellular pathogens.
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Affiliation(s)
- Viraga Haridas
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, United States; Department of Pediatrics, Harvard Medical School, United States
| | - Shahin Ranjbar
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, United States; Department of Pediatrics, Harvard Medical School, United States
| | - Ivan A Vorobjev
- School of Science and Technology, Nazarbayev University, Kazakhstan; A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Russia; Department of Cell Biology and Histology, M.V. Lomonosov Moscow State University, Russia
| | - Anne E Goldfeld
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, United States; Department of Pediatrics, Harvard Medical School, United States.
| | - Natasha S Barteneva
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, United States; Department of Pediatrics, Harvard Medical School, United States; School of Science and Technology, Nazarbayev University, Kazakhstan.
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5
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Cai H, Chen S, Xu S, Sun Y, Bai Q, Lu C, Chen Y, Fu X, Xu G, Chen L. Deficiency of LIGHT signaling pathway exacerbates Chlamydia psittaci respiratory tract infection in mice. Microb Pathog 2016; 100:250-256. [PMID: 27725282 DOI: 10.1016/j.micpath.2016.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 09/27/2016] [Accepted: 10/06/2016] [Indexed: 11/28/2022]
Abstract
LIGHT, a costimulatory member of the immunoglobulin superfamily (Ig SF), can greatly impact T cell activation. The role of the LIGHT signaling pathway in chlamydial infection was evaluated in mice following respiratory tract infection with Chlamydia psittaci. Compared with wild type (WT) mice, LIGHT knockout (KO) mice showed significant reduction of body weight, much lower survival rate, higher bacterial burden, prolonged infection time courses and more severe pathological changes in lung tissue. The mRNA levels of IFN-γ, TNF-α, IL-17 and IL-12 in the lung tissue of LIGHT KO mice were significantly lower than those in WT mice. While there was no obvious difference in the percentages of CD4+ and CD8+ T cells in the spleens of the two groups of mice, there was a markedly elevated percentage of CD4+ CD25+ FoxP3+ Treg cells in LIGHT KO mice. Together, these results demonstrate that the LIGHT signaling pathway is not only required for inflammatory cytokine production as part of the host response to chlamydial infection, but also influences the differentiation of CD4+ CD25+ FoxP3+ Treg cells, both of which may be essential for control of C. psittaci respiratory tract infection.
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Affiliation(s)
- Hengling Cai
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China; Medical College, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Shenghua Chen
- Medical College, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Sha Xu
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Yuanbin Sun
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Qinqin Bai
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Chunxue Lu
- Medical College, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Yuyu Chen
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 421000, China
| | - Xizong Fu
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China
| | - Guilian Xu
- Institute of Immunology, The Third Military Medical University, Chongqing 400038, China.
| | - Lili Chen
- College of Public Health, University of South China, 28 West Changsheng Rd., Hengyang, Hunan 421001, China.
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Radomski N, Einenkel R, Müller A, Knittler MR. Chlamydia-host cell interaction not only from a bird's eye view: some lessons fromChlamydia psittaci. FEBS Lett 2016; 590:3920-3940. [DOI: 10.1002/1873-3468.12295] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 07/06/2016] [Accepted: 07/07/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Nadine Radomski
- Friedrich-Loeffler-Institut; Institute of Immunology; Isle of Riems Germany
| | - Rebekka Einenkel
- Friedrich-Loeffler-Institut; Institute of Immunology; Isle of Riems Germany
| | - Anne Müller
- Friedrich-Loeffler-Institut; Institute of Immunology; Isle of Riems Germany
| | - Michael R Knittler
- Friedrich-Loeffler-Institut; Institute of Immunology; Isle of Riems Germany
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7
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Knittler MR, Sachse K. Chlamydia psittaci: update on an underestimated zoonotic agent. Pathog Dis 2014; 73:1-15. [PMID: 25853998 DOI: 10.1093/femspd/ftu007] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2014] [Indexed: 12/16/2022] Open
Abstract
Chlamydia (C.) psittaci is an economically relevant pathogen in poultry and pet birds, where it causes psittacosis/ornithosis, and also a human pathogen causing atypical pneumonia after zoonotic transmission. Despite its well-documented prevalence, the agent has received less attention by researchers than other Chlamydia spp. in the last decades. In the present paper, we review recently published data on C. psittaci infection and attempt to single out characteristic features distinguishing it from related chlamydial agents. It is remarkable that C. psittaci is particularly efficient in disseminating in the host organism causing systemic disease, which occasionally can take a fulminant course. At the cellular level, the pathogen's broad host cell spectrum (from epithelial cells to macrophages), its rapid entry and fast replication, proficient use of intracellular transport routes to mitochondria and the Golgi apparatus, the pronounced physical association of chlamydial inclusions with energy-providing cell compartments, as well as the subversive regulation of host cell survival during productive and persistent states facilitate the characteristic efficient growth and successful host-to-host spread of C. psittaci. At the molecular level, the pathogen was shown to upregulate essential chlamydial genes when facing the host immune response. We hypothesize that this capacity, in concert with expression of specific effectors of the type III secretion system and efficient suppression of selected host defense signals, contributes to successful establishment of the infection in the host. Concerning the immunology of host-pathogen interactions, C. psittaci has been shown to distinguish itself by coping more efficiently than other chlamydiae with pro-inflammatory mediators during early host response, which can, to some extent, explain the effective evasion and adaptation strategies of this bacterium. We conclude that thorough analysis of the large number of whole-genome sequences already available will be essential to identify genetic markers of the species-specific features and trigger more in-depth studies in cellular and animal models to address such vital topics as treatment and vaccination.
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Affiliation(s)
- Michael R Knittler
- Institute of Immunology, Friedrich-Loeffler-Institut, Isle of Riems, 07743 Jena, Germany
| | - Konrad Sachse
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, 07743 Jena, Germany
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8
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Kobayashi M, Ishida K, Matsuo J, Nakamura S, Nagasawa A, Motohashi K, Yao T, Hirai I, Yamamoto Y, Suzuki H, Shimizu C, Matsuno K, Yamaguchi H. Chlamydophila pneumoniae attachment and infection in low proteoglycan expressing human lymphoid Jurkat cells. Microb Pathog 2011; 51:209-16. [PMID: 21511028 DOI: 10.1016/j.micpath.2011.03.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Revised: 03/19/2011] [Accepted: 03/25/2011] [Indexed: 10/18/2022]
Abstract
This study investigated the proteoglycan (PG)-dependent mechanism of Chlamydophila pneumoniae attachment to lymphocytic cells. Lymphoid Jurkat cells and epithelial HEp-2 cells were statically infected with C. pneumoniae (TW183). Transmission electron microscopy and assessment of inclusion-forming units indicated that the bacteria grew normally in Jurkat cells and were capable of producing secondary infection; however, they grew at a slower rate than in HEp-2 cells. RT-PCR analysis indicated that HEp-2 cells strongly expressed PG-core protein encoding genes, thereby sustaining glycosaminoglycans (GAGs), such as heparin, on the cellular surface. Similar gene expression levels were not observed in Jurkat cells, with the exception of glypican-1. Immunofluorescence analysis also supported strong heparin expression in HEp-2 cells and minimal expression in Jurkat cells, although heparan sulfate pretreatment significantly inhibited bacterial attachment to both cell types. Immunofluorescent co-staining with antibodies against chlamydial LPS and heparin did not identify bacterial and heparin co-localization on Jurkat cells. We also confirmed that when C. pneumoniae was statically infected to human CD4(+) peripheral blood lymphocytes known not expressing detectable level of heparin, the bacteria attached to and formed inclusion bodies in the cells. Thus, the attachment mechanism of C. pneumoniae to Jurkat cells with low PG expression is unique when compared with HEp-2 cells and potentially independent of GAGs such as heparin.
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Affiliation(s)
- Miho Kobayashi
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, Hokkaido University, Nishi-5 Kita-12 Jo, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
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9
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Pennini ME, Perrinet S, Dautry-Varsat A, Subtil A. Histone methylation by NUE, a novel nuclear effector of the intracellular pathogen Chlamydia trachomatis. PLoS Pathog 2010; 6:e1000995. [PMID: 20657819 PMCID: PMC2904774 DOI: 10.1371/journal.ppat.1000995] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Accepted: 06/10/2010] [Indexed: 12/30/2022] Open
Abstract
Sequence analysis of the genome of the strict intracellular pathogen Chlamydia trachomatis revealed the presence of a SET domain containing protein, proteins that primarily function as histone methyltransferases. In these studies, we demonstrated secretion of this protein via a type III secretion mechanism. During infection, the protein is translocated to the host cell nucleus and associates with chromatin. We therefore named the protein nuclear effector (NUE). Expression of NUE in mammalian cells by transfection reconstituted nuclear targeting and chromatin association. In vitro methylation assays confirmed NUE is a histone methyltransferase that targets histones H2B, H3 and H4 and itself (automethylation). Mutants deficient in automethylation demonstrated diminished activity towards histones suggesting automethylation functions to enhance enzymatic activity. Thus, NUE is secreted by Chlamydia, translocates to the host cell nucleus and has enzymatic activity towards eukaryotic substrates. This work is the first description of a bacterial effector that directly targets mammalian histones.
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Affiliation(s)
- Meghan E. Pennini
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- CNRS URA 2582, Paris, France
| | - Stéphanie Perrinet
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- CNRS URA 2582, Paris, France
| | - Alice Dautry-Varsat
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- CNRS URA 2582, Paris, France
| | - Agathe Subtil
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
- CNRS URA 2582, Paris, France
- * E-mail:
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Shimazaki K, Chan AM, Moniz RJ, Wadehra M, Nagy A, Coulam CP, Mareninov S, Lepin EM, Wu AM, Kelly KA, Braun J, Gordon LK. Blockade of epithelial membrane protein 2 (EMP2) abrogates infection of Chlamydia muridarum murine genital infection model. ACTA ACUST UNITED AC 2009; 55:240-9. [PMID: 19159428 DOI: 10.1111/j.1574-695x.2008.00525.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
New methods are needed to eradicate or prevent Chlamydia trachomatis infections. Blockade of epithelial membrane protein 2 (EMP2) by genetic silencing or neutralizing polyclonal antibody reduced chlamydial infectivity in vitro. This study tests the prediction that recombinant anti-EMP2 diabody could reduce early chlamydial infection of the genital tract in vivo. In a murine infection model, pretreatment with anti-EMP2 diabody, as compared with control diabody, significantly reduced bacterial load, tissue production of inflammatory cytokines, recruitment of polymorphonuclear leukocytes, and local tissue inflammation. These findings support EMP2 as a potential preventative and therapeutic target for genital chlamydial infection.
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Affiliation(s)
- Kaori Shimazaki
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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11
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Heparin blocks the adhesion of E. coli O157:H7 to human colonic epithelial cells. Biochem Biophys Res Commun 2008; 369:1061-4. [DOI: 10.1016/j.bbrc.2008.02.160] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2008] [Accepted: 02/27/2008] [Indexed: 11/23/2022]
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12
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Elwell CA, Ceesay A, Kim JH, Kalman D, Engel JN. RNA interference screen identifies Abl kinase and PDGFR signaling in Chlamydia trachomatis entry. PLoS Pathog 2008; 4:e1000021. [PMID: 18369471 PMCID: PMC2267011 DOI: 10.1371/journal.ppat.1000021] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Accepted: 02/01/2008] [Indexed: 11/19/2022] Open
Abstract
To elucidate the mechanisms involved in early events in Chlamydia trachomatis infection, we conducted a large scale unbiased RNA interference screen in Drosophila melanogaster S2 cells. This allowed identification of candidate host factors in a simple non-redundant, genetically tractable system. From a library of 7,216 double stranded RNAs (dsRNA), we identified ∼226 host genes, including two tyrosine kinases, Abelson (Abl) kinase and PDGF- and VEGF-receptor related (Pvr), a homolog of the Platelet-derived growth factor receptor (PDGFR). We further examined the role of these two kinases in C. trachomatis binding and internalization into mammalian cells. Both kinases are phosphorylated upon infection and recruited to the site of bacterial attachment, but their roles in the infectious process are distinct. We provide evidence that PDGFRβ may function as a receptor, as inhibition of PDGFRβ by RNA interference or by PDGFRβ neutralizing antibodies significantly reduces bacterial binding, whereas depletion of Abl kinase has no effect on binding. Bacterial internalization can occur through activation of PDGFRβ or through independent activation of Abl kinase, culminating in phosphorylation of the Rac guanine nucleotide exchange factor (GEF), Vav2, and two actin nucleators, WAVE2 and Cortactin. Finally, we show that TARP, a bacterial type III secreted actin nucleator implicated in entry, is a target of Abl kinase. Together, our results demonstrate that PDGFRβ and Abl kinases function redundantly to promote efficient uptake of this obligate intracellular parasite. Chlamydia trachomatis infections are a worldwide problem; they are the leading cause of preventable blindness in developing nations and the most common cause of sexually transmitted disease in the Western world. Binding and entry into host cells are critical steps to the pathogenesis of this obligate intracellular parasite; however little is known regarding the mechanism of these processes. In this work, we describe a large scale RNA interference screen to identify host factors essential for early steps in C. trachomatis infection. We discover that the Platelet Derived Growth Factor Receptor β (PDGFRβ) can function as a receptor for C. trachomatis, and that activation of both PDGFRβ and Abl kinase signaling pathways by C. trachomatis leads to phosphorylation of a Rac guanine nucleotide exchange factor, Vav2, and several actin nucleators, including WAVE2, Cortactin, and TARP, a Chlamydia type III secreted effector. Our work suggests a model of redundant activation of PDGFRβ and Abl kinase upon C. trachomatis binding that culminates in cytoskeletal rearrangements that modulate efficient uptake of this obligate intracellular parasite.
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Affiliation(s)
- Cherilyn A. Elwell
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Alhaji Ceesay
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Jung Hwa Kim
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Daniel Kalman
- Department of Pathology and Laboratory of Medicine, Emory University, Atlanta, Georgia, United States of America
| | - Joanne N. Engel
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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13
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Derré I, Pypaert M, Dautry-Varsat A, Agaisse H. RNAi screen in Drosophila cells reveals the involvement of the Tom complex in Chlamydia infection. PLoS Pathog 2008; 3:1446-58. [PMID: 17967059 PMCID: PMC2042019 DOI: 10.1371/journal.ppat.0030155] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 09/13/2007] [Indexed: 12/20/2022] Open
Abstract
Chlamydia spp. are intracellular obligate bacterial pathogens that infect a wide range of host cells. Here, we show that C. caviae enters, replicates, and performs a complete developmental cycle in Drosophila SL2 cells. Using this model system, we have performed a genome-wide RNA interference screen and identified 54 factors that, when depleted, inhibit C. caviae infection. By testing the effect of each candidate's knock down on L. monocytogenes infection, we have identified 31 candidates presumably specific of C. caviae infection. We found factors expected to have an effect on Chlamydia infection, such as heparansulfate glycosaminoglycans and actin and microtubule remodeling factors. We also identified factors that were not previously described as involved in Chlamydia infection. For instance, we identified members of the Tim-Tom complex, a multiprotein complex involved in the recognition and import of nuclear-encoded proteins to the mitochondria, as required for C. caviae infection of Drosophila cells. Finally, we confirmed that depletion of either Tom40 or Tom22 also reduced C. caviae infection in mammalian cells. However, C. trachomatis infection was not affected, suggesting that the mechanism involved is C. caviae specific. Chlamydia spp. are intracellular bacterial pathogens that infect a wide range of hosts and cause various diseases, including preventable blindness in developing countries, sexually transmitted disease, and pneumonia. Chlamydia spp. are able to establish their replication niche inside the host cell, residing in a membrane-bound compartment that serves as a protector shield against immune surveillance and antimicrobial agents but also acts as a “filter” to exchange factors with the host cell. Despite the primary importance of Chlamydia for human health, little is known about the mechanisms underlying the infection process. The study of Chlamydia pathogenesis is challenging because Chlamydia spp. are not amenable to genetic manipulation and it is difficult to conduct extensive genetic approaches in the mammalian host. To circumvent these difficulties, we have used Drosophila cells to model Chlamydia infection. We conducted a genome-wide RNA interference screen and identified host factors that, when depleted, reduce Chlamydia infection. Validating our approach, we further showed that the identified factors were also required for infection in mammalian cells. This work will help us better understand the complex interaction between Chlamydia and its host and potentially identify novel targets for therapeutic treatment.
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Affiliation(s)
- Isabelle Derré
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA.
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14
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Moelleken K, Hegemann JH. The Chlamydia outer membrane protein OmcB is required for adhesion and exhibits biovar-specific differences in glycosaminoglycan binding. Mol Microbiol 2007; 67:403-19. [PMID: 18086188 PMCID: PMC2229832 DOI: 10.1111/j.1365-2958.2007.06050.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Chlamydia pneumoniae, an obligate intracellular human pathogen, causes a number of respiratory diseases. We explored the role of the conserved OmcB protein in C. pneumoniae infections, using yeast display technology. (i) Yeast cells presenting OmcB were found to adhere to human epithelial cells. (ii) Pre-incubation of OmcB yeast cells with heparin, but not other glycosaminoglycans (GAGs), abrogated adhesion. (iii) Pre-treatment of the target cells with heparinase inhibited adherence, and GAG-deficient CHO cell lines failed to bind OmcB yeast. (iv) A heparin-binding motif present near the N-terminus of OmcB is required for host cell binding. (v) Pre-treatment of chlamydial elementary bodies (EBs) with anti-OmcB antibody or pre-incubation of target cells with recombinant OmcB protein reduced infectivity upon challenge with C. pneumoniae. (vi) Adhesion of fluorescently labelled EBs to epithelial or endothelial cells was abrogated by prior addition of heparin or OmcB protein. Thus, C. pneumoniae OmcB is an adhesin that binds heparan sulphate-like GAGs. OmcB from Chlamydia trachomatis serovar L1 also adheres to human cells in a heparin-dependent way, unlike its counterpart from serovar E. We show that a single position in the OmcB sequence determines heparin dependence/independence, and variations there may reflect differences between the two serovars in cell tropism and disease pattern.
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Affiliation(s)
- Katja Moelleken
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
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15
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Marcelino I, Vachiéry N, Amaral AI, Roldão A, Lefrançois T, Carrondo MJT, Alves PM, Martinez D. Effect of the purification process and the storage conditions on the efficacy of an inactivated vaccine against heartwater. Vaccine 2007; 25:4903-13. [PMID: 17531356 DOI: 10.1016/j.vaccine.2007.04.055] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 04/05/2007] [Accepted: 04/07/2007] [Indexed: 11/20/2022]
Abstract
This work evaluates the effect of purification process and storage conditions (buffer formulation and temperature) on the efficacy of Ehrlichia ruminantium (ER) elementary bodies to be used as an inactivated vaccine candidate against heartwater. In vitro assays revealed that, to avoid major losses in ER integrity and corresponding antigenic properties, a buffer with pH between 5.6 and 8 and an osmolality above 100 mOsmol/kg H(2)O is recommended. Amongst the tested formulations, both PBS and NaCl have shown to stabilize ER antigens at -20 degrees C. To assess the protective properties of the different vaccine formulations, in vivo experiments were performed using a goat model. The results obtained showed that the preparation of ER antigens using a novel membrane-based purification strategy and a simple vaccine formulation (NaCl, -20 degrees C) induced equivalent protection to the conventional vaccine based on ER antigens prepared by a multistep centrifugation methodology and stored at -20 degrees C in PBS buffer.
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16
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Carabeo RA, Dooley CA, Grieshaber SS, Hackstadt T. Rac interacts with Abi-1 and WAVE2 to promote an Arp2/3-dependent actin recruitment during chlamydial invasion. Cell Microbiol 2007; 9:2278-88. [PMID: 17501982 DOI: 10.1111/j.1462-5822.2007.00958.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Chlamydiae are Gram-negative obligate intracellular pathogens to which access to an intracellular environment is fundamental to their development. Chlamydial attachment to host cells induces the activation of the Rac GTPase, which is required for the localization of WAVE2 at the sites of chlamydial entry. Co-immunoprecipitation experiments demonstrated that Chlamydia trachomatis infection promoted the interaction of Rac with WAVE2 and Abi-1, but not with IRSp53. siRNA depletion of WAVE2 and Abi-1 abrogated chlamydia-induced actin recruitment and significantly reduced the uptake of the pathogen by the depleted cells. Chlamydia invasion also requires the Arp2/3 complex as demonstrated by its localization to the sites of chlamydial attachment and the reduced efficiency of chlamydial invasion in cells overexpressing the VCA domain of the neural Wiskott-Aldrich syndrome protein. Thus, C. trachomatis activates Rac and promotes its interaction with WAVE2 and Abi-1 to activate the Arp2/3 complex resulting in the induction of actin cytoskeletal rearrangements that are required for invasion.
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Affiliation(s)
- Rey A Carabeo
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY, USA
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17
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Stephens RS, Poteralski JM, Olinger L. Interaction of Chlamydia trachomatis with mammalian cells is independent of host cell surface heparan sulfate glycosaminoglycans. Infect Immun 2006; 74:1795-9. [PMID: 16495553 PMCID: PMC1418640 DOI: 10.1128/iai.74.3.1795-1799.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The hypothesis that host cell surface heparan sulfate is required to promote chlamydial infection was tested using a cell line (CHO-18.4) containing a single retroviral insertion and the concomitant loss of heparan sulfate biosynthesis. Tests of chlamydial infectivity of heparan sulfate-deficient CHO-18.4 cells and parental cells, CHO-22, demonstrated that both were equally sensitive to infection by Chlamydia trachomatis serovars L2 and D. These data do not support the hypothesis and demonstrate that host cell surface heparan sulfate does not serve an essential functional role in chlamydial infectivity.
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Affiliation(s)
- Richard S Stephens
- Division of Infectious Diseases, School of Public Health, 140 Earl Warren Hall, University of California, Berkeley, CA 94720, USA.
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18
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Elwell C, Engel JN. Drosophila melanogaster S2 cells: a model system to study Chlamydia interaction with host cells. Cell Microbiol 2006; 7:725-39. [PMID: 15839901 PMCID: PMC1236988 DOI: 10.1111/j.1462-5822.2005.00508.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chlamydia spp. are major causes of important human diseases, but dissecting the host-pathogen interactions has been hampered by the lack of bacterial genetics and the difficulty in carrying out forward genetic screens in mammalian hosts. RNA interference (RNAi)-based methodologies for gene inactivation can now be easily carried out in genetically tractable model hosts, such as Drosophila melanogaster, and offer a new approach to identifying host genes required for pathogenesis. We tested whether Chlamydia trachomatis infection of D. melanogaster S2 cells recapitulated critical aspects of mammalian cell infections. As in mammalian cells, C. trachomatis entry was greatly reduced by heparin and cytochalasin D. Inclusions were formed in S2 cells, acquired Golgi-derived sphingolipids, and avoided phagolysosomal fusion. Elementary body (EB) to reticulate body (RB) differentiation was observed, however, no RB to EB development or host cell killing was observed. RNAi-mediated inactivation of Rac, a Rho GTPase recently shown to be required for C. trachomatis entry in mammalian cells, inhibits C. trachomatis infection in S2 cells. We conclude that Drosophila S2 cells faithfully mimic early events in Chlamydia host cell interactions and provides a bona fide system to systematically dissect host functions important in the pathogenesis of obligate intracellular pathogens.
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Affiliation(s)
| | - J. N. Engel
- Departments of Medicine
- Microbiology and Immunology University of California, San Francisco, CA 94143, USA
- *For correspondence. E-mail
; Tel. (+415) 476 7355; Fax (+415) 476 9364
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19
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Stuedli A, Grest P, Schiller I, Pospischil A. Mixed infections in vitro with different Chlamydiaceae strains and a cell culture adapted porcine epidemic diarrhea virus. Vet Microbiol 2005; 106:209-23. [PMID: 15778027 PMCID: PMC7126122 DOI: 10.1016/j.vetmic.2004.10.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Accepted: 10/01/2004] [Indexed: 11/30/2022]
Abstract
Assuming a synergistic or additive effect of Chlamydiaceae in coexistence with other enteropathogenic agents, the viral/bacterial interaction between a cell culture adapted porcine epidemic diarrhea virus (ca-PEDV) and different Chlamydiaceae strains was studied in vitro. Vero cells were dually infected with ca-PEDV and one of the three chlamydial strains Chlamydia trachomatis S45, Chlamydophila abortus S26/3 or Chlamydophila pecorum 1710S. Three experimental protocols were designed varying the inoculation sequence. Cell layers were first inoculated with Chlamydiaceae and 20 h later with ca-PEDV in protocol one. In protocol two, both agents were administered concurrently, whereas in protocol three, ca-PEDV was applied 20 h in advance of the Chlamydiaceae. Immunofluorescence techniques, immunohistochemical (IH) staining and electron microscopy were subsequently employed to investigate the cell layers. Using indirect immunofluorescence (IF) labeling, all mixed infections revealed dually infected cells, however, only incidentally and in low numbers. Characteristically, ca-PEDV syncytia with one or more chlamydial inclusions were detected but dually infected single cells were absent. Some syncytial cells contained enlarged C. abortus or C. pecorum inclusions with abnormally large developmental forms. In comparison with simultaneously conducted monoinfections, larger chlamydial inclusions were observed in dually infected cell layers. Experiments with C. trachomatis showed significantly increased numbers of chlamydial inclusions in dually infected cell layers compared to monoinfected ones. These findings indicate an influence of ca-PEDV on the chlamydial developmental cycle and in the case of C. trachomatis, a positive effect on chlamydial colonization in mixed infections.
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20
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Gabel BR, Elwell C, van Ijzendoorn SCD, Engel JN. Lipid raft-mediated entry is not required for Chlamydia trachomatis infection of cultured epithelial cells. Infect Immun 2004; 72:7367-73. [PMID: 15557670 PMCID: PMC529103 DOI: 10.1128/iai.72.12.7367-7373.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Using pharmacologic and biochemical criteria, we evaluated whether uptake of four different Chlamydia trachomatis serovars, D, E, K, and L2, was dependent upon lipid rafts. Our data suggest that lipid raft-mediated entry is not required for C. trachomatis infection of cultured epithelial cells.
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Affiliation(s)
- B R Gabel
- Division of Infectious Disease, Box 0654, University of California-San Francisco, San Francisco, CA 94143-0654, USA
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21
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Kuo CC, Lee A, Campbell LA. Cleavage of the N-linked oligosaccharide from the surfaces of Chlamydia species affects attachment and infectivity of the organisms in human epithelial and endothelial cells. Infect Immun 2004; 72:6699-701. [PMID: 15501806 PMCID: PMC523059 DOI: 10.1128/iai.72.11.6699-6701.2004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies demonstrated that the high-mannose oligosaccharide N linked to the Chlamydia major outer membrane protein inhibited the attachment and infectivity of the organism. The present study showed that cleavage of the glycan with N-glycanase decreased the attachment and infectivity of chlamydial organisms in human epithelial and endothelial cells.
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Affiliation(s)
- Cho-chou Kuo
- Department of Pathobiology, Box 357238, University of Washington, Seattle 98195, USA.
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22
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Clifton DR, Fields KA, Grieshaber SS, Dooley CA, Fischer ER, Mead DJ, Carabeo RA, Hackstadt T. A chlamydial type III translocated protein is tyrosine-phosphorylated at the site of entry and associated with recruitment of actin. Proc Natl Acad Sci U S A 2004; 101:10166-71. [PMID: 15199184 PMCID: PMC454183 DOI: 10.1073/pnas.0402829101] [Citation(s) in RCA: 292] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The obligate intracellular bacterium Chlamydia trachomatis rapidly induces its own entry into host cells. Initial attachment is mediated by electrostatic interactions to heparan sulfate moieties on the host cell, followed by irreversible binding to an unknown secondary receptor. This secondary binding leads to the recruitment of actin to the site of attachment, formation of an actin-rich, pedestal-like structure, and finally internalization of the bacteria. How chlamydiae induce this process is unknown. We have identified a high-molecular-mass tyrosine-phosphorylated protein that is rapidly phosphorylated on attachment to the host cell. Immunoelectron microscopy studies revealed that this tyrosine-phosphorylated protein is localized to the cytoplasmic face of the plasma membrane at the site of attachment of surface-associated chlamydiae. The phosphoprotein was isolated by immunoprecipitation with the antiphosphotyrosine antibody 4G10 and identified as the chlamydial protein CT456, a hypothetical protein with unknown function. The chlamydial protein (Tarp) appears to be translocated into the host cell by type III secretion because it is exported in a Yersinia heterologous expression assay. Phosphotyrosine signaling across the plasma membrane preceded the recruitment of actin to the site of chlamydial attachment and may represent the initial signal transduced from pathogen to the host cell. These results suggest that C. trachomatis internalization is mediated by a chlamydial type III-secreted effector protein.
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Affiliation(s)
- D R Clifton
- Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT 59840, USA
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23
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Abstract
As an intracellular pathogen, the mechanism by which Chlamydia invade eukaryotic cells represents a cornerstone to understanding chlamydial biology. The ability of chlamydiae specifically to bind heparan sulphate or heparin and the association of this ability to bind and enter mammalian host cells was approached by searching experimentally for chlamydial outer membrane proteins that bind heparin. The 60 000 molecular weight cysteine-rich outer membrane complex protein, OmcB, bound heparin. The ability of OmcB to bind heparin was supported by mapping the region of the protein with heparin-binding capacity and demonstrating that an OmcB synthetic 20-mer peptide from this region specifically bound heparin. Surface localization of OmcB was shown using monospecific antisera specific to the 20-mer OmcB peptide that bound the surfaces of elementary bodies (EB) and by heparin-binding peptide cross-linking of EB surface proteins.
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Affiliation(s)
- R S Stephens
- Division of Infectious Diseases, School of Public Health, 235 Earl Warren Hall, University of California, Berkeley, CA 94720, USA.
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24
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Taraktchoglou M, Pacey AA, Turnbull JE, Eley A. Infectivity of Chlamydia trachomatis serovar LGV but not E is dependent on host cell heparan sulfate. Infect Immun 2001; 69:968-76. [PMID: 11159992 PMCID: PMC97976 DOI: 10.1128/iai.69.2.968-976.2001] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability of heparan sulfate, heparin, and other glycosaminoglycans to inhibit the infectivity of Chlamydia trachomatis serovars E and LGV was examined using a simple competitive inhibition assay with three cell types from the human female reproductive tract, including primary human endosalpingeal cells. With the majority of the glycosaminoglycans tested, LGV was more significantly inhibited than serovar E. We have compared chlamydial infectivity between a wild-type Chinese hamster ovary cell line and two glycosaminoglycan-deficient cell lines. LGV was shown to be unable to infect heparan sulfate-deficient and GAG-deficient Chinese hamster ovary cell lines, whereas the E serovar infected these cells as efficiently as the control (nondeficient) cells. These two sets of experiments confirmed that serovar LGV is more dependent on a heparan sulfate-related mechanism of infectivity than is serovar E. This is further supported by the fact that attempts to purify a heparan sulfate-like molecule from either serovar cultured in glycosaminoglycan-deficient cell lines were nonproductive. Previous reports have suggested that chlamydia are able to produce a heparan sulfate-like molecule that is important for attachment and infectivity. We have attempted to detect possible binding of a specific heparan sulfate antibody to C. trachomatis by flow cytometry. Results showed no binding of the heparan sulfate antibody to C. trachomatis serovar LGV or E. Our results strongly indicate that chlamydiae do not produce a heparan sulfate-like molecule but rather use host cell heparan sulfate in order to infect cells.
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Affiliation(s)
- M Taraktchoglou
- Division of Genomic Medicine, The Medical School, The University of Sheffield, Sheffield, S10 2RX, United Kingdom
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25
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Hosseinzadeh S, Brewis IA, Pacey AA, Moore HD, Eley A. Coincubation of human spermatozoa with Chlamydia trachomatis in vitro causes increased tyrosine phosphorylation of sperm proteins. Infect Immun 2000; 68:4872-6. [PMID: 10948099 PMCID: PMC101686 DOI: 10.1128/iai.68.9.4872-4876.2000] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Elementary bodies (EBs) of the obligate intracellular bacterium Chlamydia trachomatis are responsible for the first step of attachment to host cells. We have studied the effects of EBs on human sperm protein tyrosine phosphorylation, which is important to sperm function. Indirect immunofluorescence using antiphosphotyrosine antibodies showed that serovar E, but not LGV, caused increased tyrosine phosphorylation which was localized to the sperm tail region. Immunoblotting revealed that serovar E caused a marked increase in tyrosine phosphorylation of 80- and 95-kDa sperm proteins, whereas serovar LGV caused increased phosphorylation of only the 80-kDa moiety. Considering the importance of tyrosine phosphorylation for sperm capacitation and other aspects of sperm function, we conclude that EBs may affect these events.
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Affiliation(s)
- S Hosseinzadeh
- Division of Molecular and Genetic Medicine, The Medical School, The University of Sheffield, Sheffield, S10 2RX, United Kingdom
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26
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Affiliation(s)
- M Scidmore-Carlson
- Host-Parasite Interactions Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana 59840, USA
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27
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Rasmussen-Lathrop SJ, Koshiyama K, Phillips N, Stephens RS. Chlamydia-dependent biosynthesis of a heparan sulphate-like compound in eukaryotic cells. Cell Microbiol 2000; 2:137-44. [PMID: 11207570 DOI: 10.1046/j.1462-5822.2000.00039.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
One hypothesis for the mechanism of chlamydial interaction with its eukaryotic host cell invokes a trimolecular mechanism, whereby a Chlamydia-derived glycosaminoglycan bridges a chlamydial acceptor molecule and a host receptor enabling attachment and invasion. We show that a heparan sulphate-specific monoclonal antibody specifically binds a glycosa-minoglycan localized to the surface of the chlamydial organism and effectively neutralizes infectivity of both C. trachomatis and C. pneumoniae. In addition to the ability of this antibody to neutralize infectivity, direct visualization using immunofluorescence demonstrated staining of chlamydial organisms localized to the intracellular vacuole. The chlamydial-associated glycosaminoglycan was specifically labelled with [14C]-glucosamine, and the labelled compound was immunoprecipitated and resolved by gel electrophoresis. The chlamydial-associated glycosaminoglycan is a high-molecular-weight compound similar in size to heparin or heparan sulphate and was sensitive to cleavage by heparan sulphate lyase. These data demonstrate that a glucosamine-containing sulphated polysaccharide is produced within the intracellular vacuole containing chlamydiae and is a target for antibody-mediated neutralization of infectivity.
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Affiliation(s)
- S J Rasmussen-Lathrop
- The Francis I. Proctor Foundation, University of California, San Francisco 94143, USA
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28
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Perfettini JL, Darville T, Gachelin G, Souque P, Huerre M, Dautry-Varsat A, Ojcius DM. Effect of Chlamydia trachomatis infection and subsequent tumor necrosis factor alpha secretion on apoptosis in the murine genital tract. Infect Immun 2000; 68:2237-44. [PMID: 10722625 PMCID: PMC97409 DOI: 10.1128/iai.68.4.2237-2244.2000] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/1999] [Accepted: 12/13/1999] [Indexed: 11/20/2022] Open
Abstract
The pathology observed during Chlamydia infection is due initially to localized tissue damage caused by the infection itself, followed by deleterious host inflammatory responses that lead to permanent scarring. We have recently reported that the infection by Chlamydia in vitro results in apoptosis of epithelial cells and macrophages and that infected monocytes secrete the proinflammatory cytokine interleukin-1beta. At the same time, proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) can also trigger apoptosis of susceptible cells. To study the possible relationship between Chlamydia trachomatis infection and apoptosis in vivo, we used the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling technique to determine whether infection may cause apoptosis in the genital tract of mice and, conversely, whether cytokines produced during the inflammatory response may modulate the level of apoptosis. Our results demonstrate that infected cells in the endocervix at day 2 or 7 after infection are sometimes apoptotic, although there was not a statistically significant change in the number of apoptotic cells in the endocervix. However, large clumps of apoptotic infected cells were observed in the lumen, suggesting that apoptotic cells may be shed from the endocervix. Moreover, there was a large increase in the number of apoptotic cells in the uterine horns and oviducts after 2 or 7 days of infection, which was accompanied by obvious signs of upper tract pathology. Interestingly, depletion of TNF-alpha led to a decrease in the level of apoptosis in the uterine horns and oviducts of animals infected for 7 days, suggesting that the inflammatory cytokines may exert part of their pathological effect via apoptosis in infected tissues.
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Affiliation(s)
- J L Perfettini
- Unité de Biologie des Interactions Cellulaires, CNRS URA 1960, Institut Pasteur, 75724 Paris Cedex 15, France
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29
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Stephens RS, Fawaz FS, Kennedy KA, Koshiyama K, Nichols B, van Ooij C, Engel JN. Eukaryotic cell uptake of heparin-coated microspheres: a model of host cell invasion by Chlamydia trachomatis. Infect Immun 2000; 68:1080-5. [PMID: 10678910 PMCID: PMC97251 DOI: 10.1128/iai.68.3.1080-1085.2000] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using polystyrene microspheres coated with heparin or heparan sulfate, it was shown that coated microspheres specifically bound eukaryotic cells and were endocytosed by nonprofessional phagocytic cells. Coated microspheres displayed properties of binding to eukaryotic cells that were similar to those of chlamydiae, and the microspheres were competitively inhibited by chlamydial organisms. Endocytosis of heparin-coated beads resulted in the tyrosine phosphorylation of a similar set of host proteins as did endocytosis of chlamydiae; however, unlike viable chlamydial organisms, which prevent phagolysosomal fusion, endocytosed beads were trafficked to a lysosomal compartment. These findings suggest that heparin-coated beads and Chlamydia trachomatis enter eukaryotic cells by similar pathways.
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Affiliation(s)
- R S Stephens
- Program in Infectious Diseases, School of Public Health, University of California, Berkeley, California 94720, USA.
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30
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Boleti H, Benmerah A, Ojcius DM, Cerf-Bensussan N, Dautry-Varsat A. Chlamydia infection of epithelial cells expressing dynamin and Eps15 mutants: clathrin-independent entry into cells and dynamin-dependent productive growth. J Cell Sci 1999; 112 ( Pt 10):1487-96. [PMID: 10212143 DOI: 10.1242/jcs.112.10.1487] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chlamydiae enter epithelial cells via a mechanism that still remains to be fully elucidated. In this study we investigated the pathway of entry of C. psittaci GPIC and C. trachomatis LGV/L2 into HeLa cells and demonstrated that it does not depend on clathrin coated vesicle formation. We used mutant cell lines defective in clathrin-mediated endocytosis due to overexpression of dominant negative mutants of either dynamin I or Eps15 proteins. When clathrin-dependent endocytosis was inhibited by overexpression of the dynK44A mutant of dynamin I (defective in GTPase activity), Chlamydia entry was not affected. However, in these cells there was a dramatic inhibition in the proliferation of Chlamydia and the growth of the chlamydia vacuole (inclusion). When clathrin-dependent endocytosis was inhibited by overexpression of an Eps15 dominant negative mutant, the entry and growth of Chlamydia was unaltered. These results indicate that the effect on the growth of Chlamydia in the dynK44A cells was not simply due to a deprivation of nutrients taken up by endocytosis. Instead, the dominant-negative mutant of dynamin most likely affects the vesicular traffic between the Chlamydia inclusion and intracellular membrane compartments. In addition, cytochalasin D inhibited Chlamydia entry by more than 90%, indicating that chlamydiae enter epithelial cells by an actin-dependent mechanism resembling phagocytosis. Finally, dynamin is apparently not involved in the formation of phagocytic vesicles containing Chlamydia.
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Affiliation(s)
- H Boleti
- Unité de Biologie des Interactions Cellulaires, Institut Pasteur, URA CNRS 1960, rue du Dr Roux, France.
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31
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Wyllie S, Ashley RH, Longbottom D, Herring AJ. The major outer membrane protein of Chlamydia psittaci functions as a porin-like ion channel. Infect Immun 1998; 66:5202-7. [PMID: 9784523 PMCID: PMC108649 DOI: 10.1128/iai.66.11.5202-5207.1998] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The major outer membrane protein (MOMP) of Chlamydia species shares several biochemical properties with classical porin proteins. Secondary structure analysis by circular dichroism now reveals that MOMP purified from Chlamydia psittaci has a predominantly beta-sheet content (62%), which is also typical of bacterial porins. Can MOMP form functional ion channels? To directly test the "porin channel" hypothesis at the molecular level, the MOMP was reconstituted into planar lipid bilayers, where it gave rise to multibarreled channels, probably trimers, which were modified by an anti-MOMP monoclonal antibody. These observations are consistent with the well-characterized homo-oligomeric nature of MOMP previously revealed by biochemical analysis and with the triple-barreled behavior of other porins. MOMP channels were weakly anion selective (PCl/PK approximately 2) and permeable to ATP. They may therefore be a route by which Chlamydia can take advantage of host nucleoside triphosphates and explain why some anti-MOMP antibodies neutralize infection. These findings have broad implications on the search for an effective chlamydial vaccine to control the significant human and animal diseases caused by these organisms.
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Affiliation(s)
- S Wyllie
- Moredun Research Institute, International Research Centre, Pentland Science Park, Penicuik, Midlothian EH26 0PZ, United Kingdom
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32
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Abstract
Our understanding of microbial adaptations to diverse and threatening environments is limited by the assumption that the behavior of individual bacteria can be accurately determined by measuring the behavior of populations. Recent advances in gene expression reporter systems, fluorescence microscopy and flow cytometry allow microbiologists to explore the complex interactions between bacteria and their environment with single cell resolution. The application of these technologies has been particularly useful in systems, such as host-pathogen interactions, where genetic analysis is often cumbersome. Recently, flow cytometry is increasingly being applied to study host-pathogen interactions.
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Affiliation(s)
- R H Valdivia
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Ojcius DM, Hellio R, Dautry-Varsat A. Distribution of endosomal, lysosomal, and major histocompatability complex markers in a monocytic cell line infected with Chlamydia psittaci. Infect Immun 1997; 65:2437-42. [PMID: 9169786 PMCID: PMC175338 DOI: 10.1128/iai.65.6.2437-2442.1997] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The intracellular fate of Chlamydia psittaci during infection of a monocytic cell line, THP1, was characterized. Cytochalasin D inhibited phagocytosis of latex beads but had no effect on infection by C. psittaci, and vacuoles expressed the transferrin receptor, suggesting accessibility to the endocytic pathway. Early Chlamydia-containing vacuoles expressed major histocompatibility complex (MHC) class I molecules, and most vacuoles fused with host cell lysosomes, since they expressed LAMP-1 and had acidic pHs. In cells prestimulated with gamma interferon, vacuoles also expressed MHC class II molecules, suggesting that the monocytes might effectively process Chlamydia-derived antigens for presentation by MHC class I and class II molecules.
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Affiliation(s)
- D M Ojcius
- Unité de Biologie des Interactions Cellulaires, CNRS URA 1960, Institut Pasteur, Paris, France.
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