1
|
Bugalhão JN, Mota LJ. The multiple functions of the numerous Chlamydia trachomatis secreted proteins: the tip of the iceberg. MICROBIAL CELL 2019; 6:414-449. [PMID: 31528632 PMCID: PMC6717882 DOI: 10.15698/mic2019.09.691] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chlamydia trachomatis serovars are obligate intracellular bacterial pathogens mainly causing ocular and urogenital infections that affect millions of people worldwide and which can lead to blindness or sterility. They reside and multiply intracellularly within a membrane-bound vacuolar compartment, known as inclusion, and are characterized by a developmental cycle involving two morphologically and physiologically distinct chlamydial forms. Completion of the developmental cycle involves the secretion of > 70 C. trachomatis proteins that function in the host cell cytoplasm and nucleus, in the inclusion membrane and lumen, and in the extracellular milieu. These proteins can, for example, interfere with the host cell cytoskeleton, vesicular and non-vesicular transport, metabolism, and immune signalling. Generally, this promotes C. trachomatis invasion into, and escape from, host cells, the acquisition of nutrients by the chlamydiae, and evasion of cell-autonomous, humoral and cellular innate immunity. Here, we present an in-depth review on the current knowledge and outstanding questions about these C. trachomatis secreted proteins.
Collapse
Affiliation(s)
- Joana N Bugalhão
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Luís Jaime Mota
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| |
Collapse
|
2
|
Flieger A, Frischknecht F, Häcker G, Hornef MW, Pradel G. Pathways of host cell exit by intracellular pathogens. MICROBIAL CELL 2018; 5:525-544. [PMID: 30533418 PMCID: PMC6282021 DOI: 10.15698/mic2018.12.659] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Host cell exit is a critical step in the life-cycle of intracellular pathogens, intimately linked to barrier penetration, tissue dissemination, inflammation, and pathogen transmission. Like cell invasion and intracellular survival, host cell exit represents a well-regulated program that has evolved during host-pathogen co-evolution and that relies on the dynamic and intricate interplay between multiple host and microbial factors. Three distinct pathways of host cell exit have been identified that are employed by three different taxa of intracellular pathogens, bacteria, fungi and protozoa, namely (i) the initiation of programmed cell death, (ii) the active breaching of host cellderived membranes, and (iii) the induced membrane-dependent exit without host cell lysis. Strikingly, an increasing number of studies show that the majority of intracellular pathogens utilize more than one of these strategies, dependent on life-cycle stage, environmental factors and/or host cell type. This review summarizes the diverse exit strategies of intracellular-living bacterial, fungal and protozoan pathogens and discusses the convergently evolved commonalities as well as system-specific variations thereof. Key microbial molecules involved in host cell exit are highlighted and discussed as potential targets for future interventional approaches.
Collapse
Affiliation(s)
- Antje Flieger
- Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | | | - Georg Häcker
- Institute of Medical Microbiology and Hygiene, Medical Center - University of Freiburg, Germany
| | - Mathias W Hornef
- Institute of Medical Microbiology, RWTH Aachen University Hospital, Germany
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Biology II, RWTH Aachen University, Germany
| |
Collapse
|
3
|
Prusty BK, Chowdhury SR, Gulve N, Rudel T. Peptidase Inhibitor 15 (PI15) Regulates Chlamydial CPAF Activity. Front Cell Infect Microbiol 2018; 8:183. [PMID: 29900129 PMCID: PMC5989220 DOI: 10.3389/fcimb.2018.00183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/11/2018] [Indexed: 12/11/2022] Open
Abstract
Obligate intracellular pathogenic Chlamydia trachomatis express several serine proteases whose roles in chlamydial development and pathogenicity are not completely understood. The chlamydial protease CPAF is expressed during the replicative phase of the chlamydial developmental cycle and is secreted into the lumen of the Chlamydia-containing vacuole called inclusion. How the secreted protease is activated in the inclusion lumen is currently not fully understood. We have identified human serine peptidase inhibitor PI15 as a potential host factor involved in the regulation of CPAF activation. Silencing expression as well as over expression of PI15 affected normal development of Chlamydia. PI15 was transported into the chlamydial inclusion lumen where it co-localized with CPAF aggregates. We show that PI15 binds to the CPAF zymogen and potentially induces CPAF protease activity at low concentrations. However, at high concentrations PI15 inhibits CPAF activity possibly by blocking its protease domain. Our findings shed light on a new aspect of chlamydial host co-evolution which involves the recruitment of host cell proteins into the inclusion to control the activation of bacterial proteases like CPAF that are important for the normal development of Chlamydia.
Collapse
Affiliation(s)
- Bhupesh K Prusty
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | | | - Nitish Gulve
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | - Thomas Rudel
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| |
Collapse
|
4
|
Abstract
It is estimated that approximately one billion people are at risk of infection with obligate intracellular bacteria, but little is known about the underlying mechanisms that govern their life cycles. The difficulty in studying Chlamydia spp., Coxiella spp., Rickettsia spp., Anaplasma spp., Ehrlichia spp. and Orientia spp. is, in part, due to their genetic intractability. Recently, genetic tools have been developed; however, optimizing the genomic manipulation of obligate intracellular bacteria remains challenging. In this Review, we describe the progress in, as well as the constraints that hinder, the systematic development of a genetic toolbox for obligate intracellular bacteria. We highlight how the use of genetically manipulated pathogens has facilitated a better understanding of microbial pathogenesis and immunity, and how the engineering of obligate intracellular bacteria could enable the discovery of novel signalling circuits in host-pathogen interactions.
Collapse
|
5
|
Wali S, Gupta R, Yu JJ, Lanka GKK, Chambers JP, Guentzel MN, Zhong G, Murthy AK, Arulanandam BP. Chlamydial protease-like activity factor mediated protection against C. trachomatis in guinea pigs. Immunol Cell Biol 2016; 95:454-460. [PMID: 27990018 PMCID: PMC5449249 DOI: 10.1038/icb.2016.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 12/02/2016] [Accepted: 12/06/2016] [Indexed: 01/30/2023]
Abstract
We have comprehensively demonstrated using the mouse model that intranasal immunization with recombinant chlamydial protease-like activity factor (rCPAF) leads to a significant reduction in bacterial burden, genital tract pathology and preserves fertility following intravaginal genital chlamydial challenge. In the present report, we evaluated the protective efficacy of rCPAF immunization in guinea pigs, a second animal model for genital chlamydial infection. Using a vaccination strategy similar to the mouse model, we intranasally immunized female guinea pigs with rCPAF plus CpG deoxynucleotides (CpG; as an adjuvant), and challenged intravaginally with C. trachomatis serovar D (CT-D). Immunization with rCPAF/CpG significantly reduced vaginal CT-D shedding and induced resolution of infection by day 24, compared to day 33 in CpG alone treated and challenged animals. Immunization induced robust anti-rCPAF serum IgG 2 weeks following the last immunization, and was sustained at a high level 4 weeks post challenge. Upregulation of antigen specific IFN-γ gene expression was observed in rCPAF/CpG vaccinated splenocytes. Importantly, a significant reduction in inflammation in the genital tissue in rCPAF/CpG-immunized guinea pigs compared to CpG-immunized animals was observed. Taken together, this study provides evidence of the protective efficacy of rCPAF as a vaccine candidate in a second animal model of genital chlamydial infection.
Collapse
Affiliation(s)
- Shradha Wali
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Rishein Gupta
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Jieh-Juen Yu
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Gopala Krishna Koundinya Lanka
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - James P Chambers
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - M Neal Guentzel
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Ashlesh K Murthy
- Department of Pathology, Midwestern University, Downers Grove, IL, USA
| | - Bernard P Arulanandam
- South Texas Center for Emerging Infectious Diseases and Center for Excellence in Infection Genomics, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| |
Collapse
|
6
|
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
| |
Collapse
|
7
|
Characterization of CPAF critical residues and secretion during Chlamydia trachomatis infection. Infect Immun 2015; 83:2234-41. [PMID: 25776755 DOI: 10.1128/iai.00275-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 03/11/2015] [Indexed: 11/20/2022] Open
Abstract
CPAF (chlamydial protease-like activity factor), a Chlamydia serine protease, is activated via proximity-induced intermolecular dimerization that triggers processing and removal of an inhibitory peptide occupying the CPAF substrate-binding groove. An active CPAF is a homodimer of two identical intramolecular heterodimers, each consisting of 29-kDa N-terminal and 35-kDa C-terminal fragments. However, critical residues for CPAF intermolecular dimerization, catalytic activity, and processing were defined in cell-free systems. Complementation of a CPAF-deficient chlamydial organism with a plasmid-encoded CPAF has enabled us to characterize CPAF during infection. The transformants expressing CPAF mutated at intermolecular dimerization, catalytic, or cleavage residues still produced active CPAF, although at a lower efficiency, indicating that CPAF can tolerate more mutations inside Chlamydia-infected cells than in cell-free systems. Only by simultaneously mutating both intermolecular dimerization and catalytic residues was CPAF activation completely blocked during infection, both indicating the importance of the critical residues identified in the cell-free systems and exploring the limit of CPAF's tolerance for mutations in the intracellular environment. We further found that active CPAF was always detected in the host cell cytoplasm while nonactive CPAF was restricted to within the chlamydial inclusions, regardless of how the infected cell samples were treated. Thus, CPAF translocation into the host cell cytoplasm correlates with CPAF enzymatic activity and is not altered by sample treatment conditions. These observations have provided new evidence for CPAF activation and translocation, which should encourage continued investigation of CPAF in chlamydial pathogenesis.
Collapse
|
8
|
Johnson KA, Lee JK, Chen AL, Tan M, Sütterlin C. Induction and inhibition of CPAF activity during analysis of Chlamydia-infected cells. Pathog Dis 2015; 73:1-8. [PMID: 25663342 DOI: 10.1093/femspd/ftv007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Studies of the chlamydial protease CPAF have been complicated by difficulties in distinguishing bona fide intracellular proteolysis from in vitro proteolysis. This confounding issue has been attributed to CPAF activity in lysates from Chlamydia-infected cells. We compared three methods that have been used to inhibit in vitro CPAF-mediated proteolysis: (1) pre-treatment of infected cells with the inhibitor clasto-lactacystin, (2) direct cell lysis in 8 M urea and (3) direct lysis in hot 1% SDS buffer. We identified a number of experimental conditions that reduce the effectiveness of each method in preventing CPAF activity during lysate preparation. The amount of in vitro proteolysis in a lysate was variable and depended on factors such as the specific substrate and the time in the intracellular infection. Additionally, we demonstrated for the first time that artifactual CPAF activity is induced before cell lysis by standard cell detachment methods, including trypsinization. Protein analysis of Chlamydia-infected cells therefore requires precautions to inhibit CPAF activity during both cell detachment and lysate preparation, followed by verification that the cell lysates do not contain residual CPAF activity. These concerns about artifactual proteolysis extend beyond studies of CPAF function because they have the potential to affect the analyses of host and chlamydial proteins from Chlamydia-infected cells.
Collapse
Affiliation(s)
- Kirsten A Johnson
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Jennifer K Lee
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Allan L Chen
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA 92697-4025, USA Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA 92697-4025, USA
| | - Ming Tan
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA 92697-4025, USA School of Medicine, UC Irvine, Irvine CA 92697-3950, USA
| | - Christine Sütterlin
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697-2300, USA
| |
Collapse
|
9
|
Branković I, van Ess EF, Noz MP, Wiericx WAJ, Spaargaren J, Morré SA, Ouburg S. NOD1 in contrast to NOD2 functional polymorphism influence Chlamydia trachomatis infection and the risk of tubal factor infertility. Pathog Dis 2015; 73:1-9. [PMID: 25854006 DOI: 10.1093/femspd/ftu028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2014] [Indexed: 01/01/2023] Open
Abstract
Intracellular pattern-recognition receptors NOD1 and NOD2 are capable of sensing common structural units of bacterial walls. Recognition triggers specific immune signalling pathways and leads to pro-inflammatory cytokine upregulation and adequate immune response. We investigated whether two functional polymorphisms in NOD1 and NOD2 exert an effect on susceptibility to (STD patients) and severity of (female patients visiting the fertility clinic) Chlamydia trachomatis infection in 807 Dutch Caucasian women. A significant association of the NOD1 +32656 GG insertion variant with protection against infection with C. trachomatis has been detected [p: 0.0057; OR: 0.52]. When comparing C. trachomatis-positive women without symptoms to C. trachomatis-positive women with symptoms, and to C. trachomatis-positive women with TFI, we observed an increasing trend in carriage of the GG allele [Ptrend: 0.0003]. NOD2 1007fs failed to reveal an association. We hypothesize that the underlying mechanism might be a functional effect of the GG insertion on IFN-beta-dependent regulation of immune response in the genital tract. The research is part of an ongoing effort of identifying key polymorphisms that determine the risk of TFI and effectively translating them into the clinical setting for the purpose of optimizing diagnostic management of women at risk for developing TFI.
Collapse
Affiliation(s)
- Ivan Branković
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 HV Amsterdam, The Netherlands Institute for Public Health Genomics, Department of Genetics and Cell Biology, School for Oncology and Developmental Biology (GROW), Faculty of Health, Medicine and Life Sciences, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Eleanne F van Ess
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - Marlies P Noz
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - Wilhelmina Anke J Wiericx
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - Joke Spaargaren
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - Servaas A Morré
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 HV Amsterdam, The Netherlands Institute for Public Health Genomics, Department of Genetics and Cell Biology, School for Oncology and Developmental Biology (GROW), Faculty of Health, Medicine and Life Sciences, Maastricht University, 6200 MD Maastricht, The Netherlands Dutch Chlamydia trachomatis Reference Laboratory, Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - Sander Ouburg
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
Tan M, Sütterlin C. The Chlamydia protease CPAF: caution, precautions and function. Pathog Dis 2014; 72:7-9. [PMID: 25146758 DOI: 10.1111/2049-632x.12213] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 08/14/2014] [Indexed: 01/24/2023] Open
Affiliation(s)
- Ming Tan
- Department of Microbiology and Molecular Genetics, UC Irvine, Irvine, CA, USA; Department of Medicine, UC Irvine, Irvine, CA, USA.
| | | |
Collapse
|
12
|
Häcker G, Heuer D, Ojcius DM. Is the hoopla over CPAF justified? Pathog Dis 2014; 72:1-2. [PMID: 25113036 DOI: 10.1111/2049-632x.12211] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 08/04/2014] [Indexed: 01/19/2023] Open
Affiliation(s)
- Georg Häcker
- Institute of Medical Microbiology and Hygiene, University Medical Centre Freiburg, Freiburg, Germany.
| | | | | |
Collapse
|