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Walker FC, Derré I. Contributions of diverse models of the female reproductive tract to the study of Chlamydia trachomatis-host interactions. Curr Opin Microbiol 2024; 77:102416. [PMID: 38103413 PMCID: PMC10922760 DOI: 10.1016/j.mib.2023.102416] [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: 09/21/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/19/2023]
Abstract
Chlamydia trachomatis is a common cause of sexually transmitted infections in humans with devastating sequelae. Understanding of disease on all scales, from molecular details to the immunology underlying pathology, is essential for identifying new ways of preventing and treating chlamydia. Infection models of various complexity are essential to understand all aspects of chlamydia pathogenesis. Cell culture systems allow for research into molecular details of infection, including characterization of the unique biphasic Chlamydia developmental cycle and the role of type-III-secreted effectors in modifying the host environment to allow for infection. Multicell type and organoid culture provide means to investigate how cells other than the infected cells contribute to the control of infection. Emerging comprehensive three-dimensional biomimetic systems may fill an important gap in current models to provide information on complex phenotypes that cannot be modeled in simpler in vitro models.
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Affiliation(s)
- Forrest C Walker
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America.
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2
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Lu C, Wang J, Zhong G. Preclinical screen for protection efficacy of chlamydial antigens that are immunogenic in humans. Infect Immun 2023; 91:e0034923. [PMID: 37889004 PMCID: PMC10652899 DOI: 10.1128/iai.00349-23] [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: 08/29/2023] [Accepted: 10/02/2023] [Indexed: 10/28/2023] Open
Abstract
To search for subunit vaccine candidates, immunogenic chlamydial antigens identified in humans were evaluated for protection against both infection and pathology in a mouse genital tract infection model under three different immunization regimens. The intramuscular immunization regimen was first used to evaluate 106 chlamydial antigens, which revealed that two antigens significantly reduced while 11 increased genital chlamydial burden. The two infection-reducing antigens failed to prevent pathology and 23 additional antigens even exacerbated pathology. Thus, intranasal mucosal immunization was tested next since intranasal inoculation with live Chlamydia muridarum prevented both genital infection and pathology. Two of the 29 chlamydial antigens evaluated were found to prevent genital infection but not pathology and three exacerbate pathology. To further improve protection efficacy, a combinational regimen (intranasal priming + intramuscular boosting + a third intraperitoneal/subcutaneous boost) was tested. This regimen identified four infection-reducing antigens, but only one of them prevented pathology. Unfortunately, this protective antigen was not advanced further due to its amino acid sequence homology with several human molecules. Two pathology-exacerbating antigens were also found. Nevertheless, intranasal mucosal priming with viable C. muridarum in control groups consistently prevented both genital infection and pathology regardless of the subsequent boosters. Thus, screening 140 different chlamydial antigens with 21 repeated multiple times in 17 experiments failed to identify a subunit vaccine candidate but demonstrated the superiority of viable chlamydial organisms in inducing immunity against both genital infection and pathology, laying the foundation for developing a live-attenuated Chlamydia vaccine.
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Affiliation(s)
- Chunxue Lu
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, Hunan, China
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Jie Wang
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center, San Antonio, Texas, USA
- Department of Immunology, Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Guangming Zhong
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center, San Antonio, Texas, USA
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3
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Bastidas RJ, Valdivia RH. The emerging complexity of Chlamydia trachomatis interactions with host cells as revealed by molecular genetic approaches. Curr Opin Microbiol 2023; 74:102330. [PMID: 37247566 PMCID: PMC10988583 DOI: 10.1016/j.mib.2023.102330] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023]
Abstract
Chlamydia trachomatis (Ct) is an intracellular bacterial pathogen that relies on the activity of secreted proteins known as effectors to promote replication and avoidance of immune clearance. Understanding the contribution of Ct effectors to pathogenesis has proven to be challenging, given that these proteins often perform multiple functions during intracellular infection. Recent advances in molecular genetic analysis of Ct have provided valuable insights into the multifaceted nature of secreted effector proteins and their impact on the interaction between Ct and host cells and tissues. This review highlights significant findings from genetic analysis of Ct effector functions, shedding light on their diverse roles. We also discuss the challenges faced in this field of study and explore potential opportunities for further research.
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Affiliation(s)
- Robert J Bastidas
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Raphael H Valdivia
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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Xie L, He C, Chen J, Tang L, Zhou Z, Zhong G. Suppression of Chlamydial Pathogenicity by Nonspecific CD8 + T Lymphocytes. Infect Immun 2020; 88:e00315-20. [PMID: 32747602 PMCID: PMC7504968 DOI: 10.1128/iai.00315-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022] Open
Abstract
Chlamydia trachomatis, a leading infectious cause of tubal infertility, induces upper genital tract pathology, such as hydrosalpinx, which can be modeled with Chlamydia muridarum infection in mice. Following C. muridarum inoculation, wild-type mice develop robust hydrosalpinx, but OT1 mice fail to do so because their T cell receptors are engineered to recognize a single ovalbumin epitope (OVA457-462). These observations have demonstrated a critical role of Chlamydia-specific T cells in chlamydial pathogenicity. In the current study, we have also found that OT1 mice can actively inhibit chlamydial pathogenicity. First, depletion of CD8+ T cells from OT1 mice led to the induction of significant hydrosalpinx by Chlamydia, indicating that CD8+ T cells are necessary to inhibit chlamydial pathogenicity. Second, adoptive transfer of CD8+ T cells from OT1 mice to CD8 knockout mice significantly reduced chlamydial induction of hydrosalpinx, demonstrating that OT1 CD8+ T cells are sufficient for attenuating chlamydial pathogenicity in CD8 knockout mice. Finally, CD8+ T cells from OT1 mice also significantly inhibited hydrosalpinx development in wild-type mice following an intravaginal inoculation with Chlamydia Since T cells in OT1 mice are engineered to recognize only the OVA457-462 epitope, the above observations have demonstrated a chlamydial antigen-independent immune mechanism for regulating chlamydial pathogenicity. Further characterization of this mechanism may provide information for developing strategies to reduce infertility-causing pathology induced by infections.
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Affiliation(s)
- Lingxiang Xie
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Conghui He
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Jianlin Chen
- The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Lingli Tang
- The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Zhiguang Zhou
- The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Guangming Zhong
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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5
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Lu C, Sun Z, Chen H, Chen L, Zhu C, Chen C, Li C, Peng B, Zhong G. Proteome array of antibody responses to Chlamydia trachomatis infection in nonhuman primates. Life Sci 2020; 248:117444. [PMID: 32084433 DOI: 10.1016/j.lfs.2020.117444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/09/2020] [Accepted: 02/17/2020] [Indexed: 11/29/2022]
Abstract
AIMS Nonhuman primates have been used to investigate pathogenic mechanisms and evaluate immune responses following Chlamydia trachomatis inoculation. This study aimed to systemically profile antibody responses to C. trachomatis infection in nonhuman primates. MATERIALS AND METHODS Sera were obtained from 4 pig-tailed and 8 long-tailed macaques which were intravaginally or ocularly infected with live C. trachomatis organisms, and analyzed by C. trachomatis proteome array of antigens. KEY FINDINGS The sera from 12 macaques recognized total 172 C. trachomatis antigens. While 84 antigens were recognized by pig-tailed macaques intravaginally infected with serovar D strain, 125 antigens were recognized by long-tailed macaques ocularly infected with serovar A, and 37 antigens were recognized by both. Ocular inoculation with virulent A2497 strain induced antibodies to more antigens. Among the antigens uniquely recognized by A2497 strain infected macaques, outer membrane complex B antigen (OmcB) induced robust antibody response. Although macaques infected by less virulent A/HAR-13 strain failed to develop antibodies to OmcB, reinfection by A2497 strain induced high levels of antibodies to OmcB. SIGNIFICANCE Proteome array has revealed a correlation of chlamydial infection invasiveness with chlamydial antigen immunogenicity, and identified antibody responses to OmcB potentially as biomarkers for invasive infection with C. trachomatis.
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Affiliation(s)
- Chunxue Lu
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Zhenjie Sun
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Hui Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Lili Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Cuiming Zhu
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Chaoqun Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China
| | - Changqing Li
- Nanyue Biopharmaceutical Co. Ltd., Hunan Province Innovative Training Base for Postgraduates, University of South China and Nanyue Biopharmaceutical Co. Ltd., Hengyang, Hunan 421001, China
| | - Bo Peng
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, Hunan 421001, China; Department of Pathology, Hengyang Medical College, University of South China, Hengyang, Hunan 421001, China.
| | - Guangming Zhong
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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6
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Development of Transposon Mutagenesis for Chlamydia muridarum. J Bacteriol 2019; 201:JB.00366-19. [PMID: 31501283 DOI: 10.1128/jb.00366-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/27/2019] [Indexed: 12/18/2022] Open
Abstract
Functional genetic analysis of Chlamydia has been a challenge due to the historical genetic intractability of Chlamydia, although recent advances in chlamydial genetic manipulation have begun to remove these barriers. Here, we report the development of the Himar C9 transposon system for Chlamydia muridarum, a mouse-adapted Chlamydia species that is widely used in Chlamydia infection models. We demonstrate the generation and characterization of an initial library of 33 chloramphenicol (Cam)-resistant, green fluorescent protein (GFP)-expressing C. muridarum transposon mutants. The majority of the mutants contained single transposon insertions spread throughout the C. muridarum chromosome. In all, the library contained 31 transposon insertions in coding open reading frames (ORFs) and 7 insertions in intergenic regions. Whole-genome sequencing analysis of 17 mutant clones confirmed the chromosomal locations of the insertions. Four mutants with transposon insertions in glgB, pmpI, pmpA, and pmpD were investigated further for in vitro and in vivo phenotypes, including growth, inclusion morphology, and attachment to host cells. The glgB mutant was shown to be incapable of complete glycogen biosynthesis and accumulation in the lumen of mutant inclusions. Of the 3 pmp mutants, pmpI was shown to have the most pronounced growth attenuation defect. This initial library demonstrates the utility and efficacy of stable, isogenic transposon mutants for C. muridarum The generation of a complete library of C. muridarum mutants will ultimately enable comprehensive identification of the functional genetic requirements for Chlamydia infection in vivo IMPORTANCE Historical issues with genetic manipulation of Chlamydia have prevented rigorous functional genetic characterization of the ∼1,000 genes in chlamydial genomes. Here, we report the development of a transposon mutagenesis system for C. muridarum, a mouse-adapted Chlamydia species that is widely used for in vivo investigations of chlamydial pathogenesis. This advance builds on the pioneering development of this system for C. trachomatis We demonstrate the generation of an initial library of 33 mutants containing stable single or double transposon insertions. Using these mutant clones, we characterized in vitro phenotypes associated with genetic disruptions in glycogen biosynthesis and three polymorphic outer membrane proteins.
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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: 34] [Impact Index Per Article: 6.8] [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.
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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
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Dudiak BM, Maksimchuk KR, Bednar MM, Podracky CJ, Burg JM, Nguyen TM, Nwogbo FO, Valdivia RH, McCafferty DG. Insights into the Autoproteolytic Processing and Catalytic Mechanism of the Chlamydia trachomatis Virulence-Associated Protease CPAF. Biochemistry 2019; 58:3527-3536. [PMID: 31386347 DOI: 10.1021/acs.biochem.9b00522] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
CPAF (chlamydial protease-like activity factor) is a Chlamydia trachomatis protease that is translocated into the host cytosol during infection. CPAF activity results in dampened host inflammation signaling, cytoskeletal remodeling, and suppressed neutrophil activation. Although CPAF is an emerging antivirulence target, its catalytic mechanism has been unexplored to date. Steady state kinetic parameters were obtained for recombinant CPAF with vimentin-derived peptide substrates using a high-performance liquid chromatography-based discontinuous assay (kcat = 45 ± 0.6 s-1; kcat/Km = 0.37 ± 0.02 μM-1 s-1) or a new fluorescence-based continuous assay (kcat = 23 ± 0.7 s-1; kcat/Km = 0.29 ± 0.03 μM-1 s-1). Residues H105, S499, E558, and newly identified D103 were found to be indispensable for autoproteolytic processing by mutagenesis, while participation of C500 was ruled out despite its proximity to the S499 nucleophile. Pre-steady state kinetics indicated a burst kinetic profile, with fast acylation (kacyl = 110 ± 2 s-1) followed by slower, partially rate-limiting deacylation (kdeacyl = 57 ± 1 s-1). Both kcat- and kcat/Km-pH profiles showed single acidic limb ionizations with pKa values of 6.2 ± 0.1 and 6.5 ± 0.1, respectively. A forward solvent deuterium kinetic isotope effect of 2.6 ± 0.1 was observed for D2Okcatapp, but a unity effect was found for D2Okcat/Kmapp. The kcat proton inventory was linear, indicating transfer of a single proton in the rate-determining transition state, most likely from H105. Collectively, these data provide support for the classification of CPAF as a serine protease and provide a mechanistic foundation for the future design of inhibitors.
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Chlamydia muridarum Induces Pathology in the Female Upper Genital Tract via Distinct Mechanisms. Infect Immun 2019; 87:IAI.00145-19. [PMID: 31085708 DOI: 10.1128/iai.00145-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 05/06/2019] [Indexed: 12/23/2022] Open
Abstract
Sexually transmitted infection with Chlamydia trachomatis may lead to fibrotic blockage in women's upper genital tracts, resulting in tubal infertility. Intravaginal inoculation with C. muridarum readily induces fibrotic blockage or hydrosalpinx in mice and is used for investigating C. trachomatis pathogenicity. Using this model in combination with an antibody depletion approach, we confirmed CD4+ T cell-mediated protective immunity and a CD8+ T cell-dependent pathogenic mechanism during chlamydial infection in C57BL/6J mice. However, when mice genetically deficient in CD8+ T cells were evaluated, we found, surprisingly, that these mice were still able to develop robust hydrosalpinx following C. muridarum infection, both contradicting the observation made in C57BL/6J mice and suggesting a pathogenic mechanism that is independent of CD8+ T cells. We further found that depletion of CD4+ T cells from CD8+ T cell-deficient mice significantly reduced chlamydial induction of hydrosalpinx, indicating that CD4+ T cells became pathogenic in mice genetically deficient in CD8+ T cells. Since depletion of CD4+ T cells both promoted chlamydial infection and reduced chlamydial pathogenicity in CD8+ T cell-deficient mice, we propose that in the absence of CD8+ T cells, some CD4+ T cells may remain protective (as in C57BL/6J mice), while others may directly contribute to chlamydial pathogenicity. Thus, chlamydial pathogenicity can be mediated by distinct host mechanisms, depending upon host genetics and infection conditions. The CD8+ T cell-deficient mouse model may be useful for further investigating the mechanisms by which CD4+ T cells promote chlamydial pathogenicity.
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10
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Chlamydia trachomatis paralyses neutrophils to evade the host innate immune response. Nat Microbiol 2018; 3:824-835. [PMID: 29946164 DOI: 10.1038/s41564-018-0182-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 05/18/2018] [Indexed: 11/08/2022]
Abstract
Chlamydia trachomatis, an obligate intracellular human pathogen, is a major cause of sexually transmitted diseases. Infections often occur without symptoms, a feature that has been attributed to the ability of the pathogen to evade the host immune response. We show here that C. trachomatis paralyses the host immune system by preventing the activation of polymorphic nuclear leukocytes (PMNs). PMNs infected with Chlamydia fail to produce neutrophil extracellular traps and the bacteria are able to survive in PMNs for extended periods of time. We have identified the secreted chlamydial protease-like activating factor (CPAF) as an effector mediating the evasion of the innate immune response since CPAF-deficient Chlamydia activate PMNs and are subsequently efficiently killed. CPAF suppresses the oxidative burst and interferes with chemical-mediated activation of neutrophils. We identified formyl peptide receptor 2 (FPR2) as a target of CPAF. FPR2 is cleaved by CPAF and released from the surface of PMNs. In contrast to previously described subversion mechanisms that mainly act on already activated PMNs, we describe here details of how Chlamydia actively paralyses PMNs, including the formation of neutrophil extracellular traps, to evade the host's innate immune response.
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Mackern-Oberti JP, Motrich RD, Damiani MT, Saka HA, Quintero CA, Sánchez LR, Moreno-Sosa T, Olivera C, Cuffini C, Rivero VE. Male genital tract immune response against Chlamydia trachomatis infection. Reproduction 2018; 154:R99-R110. [PMID: 28878094 DOI: 10.1530/rep-16-0561] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 07/01/2017] [Accepted: 07/11/2017] [Indexed: 01/01/2023]
Abstract
Chlamydia trachomatis is the most commonly reported agent of sexually transmitted bacterial infections worldwide. This pathogen frequently leads to persistent, long-term, subclinical infections, which in turn may cause severe pathology in susceptible hosts. This is in part due to the strategies that Chlamydia trachomatis uses to survive within epithelial cells and to evade the host immune response, such as subverting intracellular trafficking, interfering signaling pathways and preventing apoptosis. Innate immune receptors such as toll-like receptors expressed on epithelial and immune cells in the genital tract mediate the recognition of chlamydial molecular patterns. After bacterial recognition, a subset of pro-inflammatory cytokines and chemokines are continuously released by epithelial cells. The innate immune response is followed by the initiation of the adaptive response against Chlamydia trachomatis, which in turn may result in T helper 1-mediated protection or in T helper 2-mediated immunopathology. Understanding the molecular mechanisms developed by Chlamydia trachomatis to avoid killing and host immune response would be crucial for designing new therapeutic approaches and developing protective vaccines. In this review, we focus on chlamydial survival strategies and the elicited immune responses in male genital tract infections.
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Affiliation(s)
- Juan Pablo Mackern-Oberti
- Instituto de Medicina y Biología Experimental de Cuyo. IMBECU-CONICETMendoza, Argentina .,Instituto de Fisiología. Facultad de Ciencias MédicasUniversidad Nacional de Cuyo, Mendoza, Argentina
| | - Rubén Darío Motrich
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Maria Teresa Damiani
- Instituto de Histología y Embriología de Mendoza. IHEM-CONICETFacultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Héctor Alex Saka
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | | | - Leonardo Rodolfo Sánchez
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Tamara Moreno-Sosa
- Instituto de Medicina y Biología Experimental de Cuyo. IMBECU-CONICETMendoza, Argentina
| | - Carolina Olivera
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Cecilia Cuffini
- Instituto de Virología Dr. J. M. VanellaFacultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Virginia Elena Rivero
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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12
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Recalde G, Moreno-Sosa T, Yúdica F, Quintero CA, Sánchez MB, Jahn GA, Kalergis AM, Mackern-Oberti JP. Contribution of sex steroids and prolactin to the modulation of T and B cells during autoimmunity. Autoimmun Rev 2018. [DOI: 10.1016/j.autrev.2018.03.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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13
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Transformation of Chlamydia: current approaches and impact on our understanding of chlamydial infection biology. Microbes Infect 2018; 20:445-450. [PMID: 29409975 DOI: 10.1016/j.micinf.2018.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 01/04/2018] [Accepted: 01/05/2018] [Indexed: 12/11/2022]
Abstract
The intonation "The king is dead, long live the king" aptly describes the state of Chlamydia research. Genetic-based approaches are rapidly replacing correlative strategies to provide new insights. We describe how current transformation technologies are enhancing progress in understanding Chlamydia infection biology and present key opportunities for further development.
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14
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Zhong G. Chlamydia Spreading from the Genital Tract to the Gastrointestinal Tract - A Two-Hit Hypothesis. Trends Microbiol 2017; 26:611-623. [PMID: 29289422 DOI: 10.1016/j.tim.2017.12.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/21/2017] [Accepted: 12/06/2017] [Indexed: 12/18/2022]
Abstract
Chlamydia trachomatis, a leading bacterial cause of sexually transmitted infection-induced infertility, is frequently detected in the gastrointestinal tract. Chlamydia muridarum, a model pathogen for investigating C. trachomatis pathogenesis, readily spreads from the mouse genital tract to the gastrointestinal tract, establishing long-lasting colonization. C. muridarum mutants, despite their ability to activate acute oviduct inflammation, are attenuated in inducing tubal fibrosis and are no longer able to colonize the gastrointestinal tract, suggesting that the spread of C. muridarum to the gastrointestinal tract may contribute to its pathogenicity in the upper genital tract. However, gastrointestinal C. muridarum cannot directly autoinoculate the genital tract. Both antigen-specific CD8+ T cells and profibrotic cytokines, such as TNFα and IL-13, are essential for C. muridarum to induce tubal fibrosis; this may be induced by the gastrointestinal C. muridarum, as a second hit, to transmucosally convert tubal repairing - initiated by C. muridarum infection of tubal epithelial cells (serving as the first hit) - into pathogenic fibrosis. Testing the two-hit mouse model should both add new knowledge to the growing list of mechanisms by which gastrointestinal microbes contribute to pathologies in extragastrointestinal tissues and provide information for investigating the potential role of gastrointestinal C. trachomatis in human chlamydial pathogenesis.
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Affiliation(s)
- Guangming Zhong
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health, Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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Zhong G, Brunham RC, de la Maza LM, Darville T, Deal C. National Institute of Allergy and Infectious Diseases workshop report: "Chlamydia vaccines: The way forward". Vaccine 2017; 37:7346-7354. [PMID: 29097007 DOI: 10.1016/j.vaccine.2017.10.075] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 10/24/2017] [Indexed: 01/06/2023]
Abstract
Chlamydia trachomatis (Ct), an intracellular pathogen, is the most common bacterial sexually transmitted infection. In addition to acute cervicitis and urethritis, Ct can lead to serious sequelae of significant public health burden including pelvic inflammatory disease (PID) and infertility. Ct control efforts have not resulted in desired outcomes such as reduced incidence and reinfection, and this highlights the need for the development of an effective Ct vaccine. To this end, NIAID organized a workshop to consider the current status of Ct vaccine research and address critical questions in Ct vaccine design and clinical testing. Topics included the goal(s) of a vaccine and the feasibility of achieving these goals, animal models of infection including mouse and nonhuman primate (NHP) models, and correlates of protection to guide vaccine design. Decades of research have provided both whole cell-based and subunit vaccine candidates for development. At least one is currently in clinical development and efforts now need to be directed toward further development of the most attractive candidates. Overall, the discussions and presentations from the workshop highlighted optimism about the current status of Ct vaccine research and detailed the remaining gaps and questions needed to move vaccines forward.
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Affiliation(s)
- Guangming Zhong
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
| | - Robert C Brunham
- Vaccine Research Laboratory, UBC Centre for Disease Control, University of British Columbia, Vancouver, BC V5Z 4R4, Canada
| | - Luis M de la Maza
- Department of Pathology and Laboratory Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Toni Darville
- Department of Pediatrics, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599-7509, USA
| | - Carolyn Deal
- Division of Microbiology and Infectious Diseases, NIAID, Bethesda, MD, USA
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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.
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Update on Chlamydia trachomatis Vaccinology. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00543-16. [PMID: 28228394 DOI: 10.1128/cvi.00543-16] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Attempts to produce a vaccine to protect against Chlamydia trachomatis-induced trachoma were initiated more than 100 years ago and continued for several decades. Using whole organisms, protective responses were obtained. However, upon exposure to C. trachomatis, disease exacerbation developed in some immunized individuals, precluding the implementation of the vaccine. Evidence of the role of C. trachomatis as a sexually transmitted pathogen started to emerge in the 1960s, and it soon became evident that it can cause acute infections and long-term sequelae in women, men, and newborns. The main focus of this minireview is to summarize recent findings and discuss formulations, including antigens, adjuvants, routes, and delivery systems for immunization, primarily explored in the female mouse model, with the goal of implementing a vaccine against C. trachomatis genital infections.
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Zhong G. Chlamydial Plasmid-Dependent Pathogenicity. Trends Microbiol 2016; 25:141-152. [PMID: 27712952 DOI: 10.1016/j.tim.2016.09.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/11/2016] [Accepted: 09/19/2016] [Indexed: 10/20/2022]
Abstract
Most Chlamydia species carry a 7.5kb plasmid encoding eight open reading frames conventionally called plasmid glycoproteins 1-8 or pGP1-8. Although the plasmid is not critical for chlamydial growth in vitro, its role in chlamydial pathogenesis is clearly demonstrated in the genital tracts of mice infected with Chlamydia muridarum, a model for investigating the human pathogen Chlamydia trachomatis. Plasmid-free C. trachomatis is also attenuated in both the mouse genital tract and nonhuman primate ocular tissue. Deficiency in pGP3 alone, which is regulated by pGP4, largely reproduced the in vivo but not in vitro phenotypes of the plasmid-free organisms, suggesting that pGP3 is a key in vivo virulence factor. The positive and negative regulations of some chromosomal genes by pGP4 and pGP5, respectively, may allow the plasmid to promote chlamydial adaptation to varied animal tissue environments. The focus of this review is to summarize the progress on the pathogenic functions of the plasmid-encoded open reading frames, which may motivate further investigation of the molecular mechanisms of chlamydial pathogenicity and development of medical utility of the chlamydial plasmid system.
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Affiliation(s)
- Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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Chlamydial Protease-Like Activity Factor and Type III Secreted Effectors Cooperate in Inhibition of p65 Nuclear Translocation. mBio 2016; 7:mBio.01427-16. [PMID: 27677792 PMCID: PMC5040114 DOI: 10.1128/mbio.01427-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The chlamydial protease-like activity factor (CPAF) is hypothesized to be an important secreted virulence factor; however, challenges in denaturing its proteolytic activity have hampered attempts to identify its legitimate targets. Here, we use a genetic and proteomic approach to identify authentic CPAF targets. Human epithelial cells infected with CPAF-sufficient and CPAF-deficient chlamydiae were lysed using known CPAF-denaturing conditions. Their protein profiles were analyzed using isobaric mass tags and liquid chromatography-tandem mass spectrometry. Comparative analysis of CPAF-sufficient and CPAF-deficient infections identified a limited number of CPAF host and chlamydial protein targets. Host targets were primarily interferon-stimulated gene products, whereas chlamydial targets were type III secreted proteins. We provide evidence supporting a cooperative role for CPAF and type III secreted effectors in blocking NF-κB p65 nuclear translocation, resulting in decreased beta interferon and proinflammatory cytokine synthesis. Genetic complementation of null organisms with CPAF restored p65 nuclear translocation inhibition and proteolysis of chlamydial type III secreted effector proteins (T3SEs). We propose that CPAF and T3SEs cooperate in the inhibition of host innate immunity. Chlamydia trachomatis is an important human pathogen responsible for over 100 million infections each year worldwide. Its success as an intracellular pathogen revolves around its ability to evade host immunity. The chlamydial protease-like activity factor (CPAF) is a conserved serine protease secreted into the host cytosol of infected cells that is thought to play an important role in immune evasion. Currently, CPAF’s authentic in situ target(s) and mechanism of action in immune evasion are poorly characterized. Using a CPAF-deficient strain and high-throughput proteomics, we report novel CPAF host and chlamydial targets. Host targets were primarily interferon-stimulated genes, whereas chlamydial targets were exclusively type III secreted proteins. We propose a novel mechanism for CPAF and type III secreted proteins in the evasion of host innate immune responses. These findings provide new insights into CPAF’s function as a virulence factor and a better understanding of how chlamydiae evade host immunity.
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