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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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Cheong HC, Sulaiman S, Looi CY, Chang LY, Wong WF. Chlamydia Infection Remodels Host Cell Mitochondria to Alter Energy Metabolism and Subvert Apoptosis. Microorganisms 2023; 11:1382. [PMID: 37374883 DOI: 10.3390/microorganisms11061382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 06/29/2023] Open
Abstract
Chlamydia infection represents an important cause for concern for public health worldwide. Chlamydial infection of the genital tract in females is mostly asymptomatic at the early stage, often manifesting as mucopurulent cervicitis, urethritis, and salpingitis at the later stage; it has been associated with female infertility, spontaneous abortion, ectopic pregnancy, and cervical cancer. As an obligate intracellular bacterium, Chlamydia depends heavily on host cells for nutrient acquisition, energy production, and cell propagation. The current review discusses various strategies utilized by Chlamydia in manipulating the cell metabolism to benefit bacterial propagation and survival through close interaction with the host cell mitochondrial and apoptotic pathway molecules.
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Affiliation(s)
- Heng Choon Cheong
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Sofiah Sulaiman
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Chung Yeng Looi
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University, Subang Jaya 47500, Selangor, Malaysia
| | - Li-Yen Chang
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
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Intracellular lifestyle of Chlamydia trachomatis and host-pathogen interactions. Nat Rev Microbiol 2023:10.1038/s41579-023-00860-y. [PMID: 36788308 DOI: 10.1038/s41579-023-00860-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2023] [Indexed: 02/16/2023]
Abstract
In recent years, substantial progress has been made in the understanding of the intracellular lifestyle of Chlamydia trachomatis and how the bacteria establish themselves in the human host. As an obligate intracellular pathogenic bacterium with a strongly reduced coding capacity, C. trachomatis depends on the provision of nutrients from the host cell. In this Review, we summarize the current understanding of how C. trachomatis establishes its intracellular replication niche, how its metabolism functions in the host cell, how it can defend itself against the cell autonomous and innate immune response and how it overcomes adverse situations through the transition to a persistent state. In particular, we focus on those processes for which a mechanistic understanding has been achieved.
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Gravett RM, Marrazzo J. What’s Old Is New: the Evolution of Lymphogranuloma Venereum Proctitis in Persons Living with HIV. Curr Infect Dis Rep 2022. [DOI: 10.1007/s11908-022-00781-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Prasad SK, Bhat S, Shashank D, C R A, R S, Rachtanapun P, Devegowda D, Santhekadur PK, Sommano SR. Bacteria-Mediated Oncogenesis and the Underlying Molecular Intricacies: What We Know So Far. Front Oncol 2022; 12:836004. [PMID: 35480118 PMCID: PMC9036991 DOI: 10.3389/fonc.2022.836004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/22/2022] [Indexed: 01/10/2023] Open
Abstract
Cancers are known to have multifactorial etiology. Certain bacteria and viruses are proven carcinogens. Lately, there has been in-depth research investigating carcinogenic capabilities of some bacteria. Reports indicate that chronic inflammation and harmful bacterial metabolites to be strong promoters of neoplasticity. Helicobacter pylori-induced gastric adenocarcinoma is the best illustration of the chronic inflammation paradigm of oncogenesis. Chronic inflammation, which produces excessive reactive oxygen species (ROS) is hypothesized to cause cancerous cell proliferation. Other possible bacteria-dependent mechanisms and virulence factors have also been suspected of playing a vital role in the bacteria-induced-cancer(s). Numerous attempts have been made to explore and establish the possible relationship between the two. With the growing concerns on anti-microbial resistance and over-dependence of mankind on antibiotics to treat bacterial infections, it must be deemed critical to understand and identify carcinogenic bacteria, to establish their role in causing cancer.
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Affiliation(s)
- Shashanka K Prasad
- Department of Biotechnology and Bioinformatics, Faculty of Life Sciences, Jagadguru Sri Shivarathreeshwara (JSS) Academy of Higher Education and Research (JSSAHER), Mysuru, India
| | - Smitha Bhat
- Department of Biotechnology and Bioinformatics, Faculty of Life Sciences, Jagadguru Sri Shivarathreeshwara (JSS) Academy of Higher Education and Research (JSSAHER), Mysuru, India
| | - Dharini Shashank
- Department of General Surgery, Adichunchanagiri Institute of Medical Sciences, Mandya, India
| | - Akshatha C R
- Department of Medical Oncology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Sindhu R
- Department of Microbiology, Faculty of Life Sciences, Jagadguru Sri Shivarathreeshwara (JSS) Academy of Higher Education and Research (JSSAHER), Mysuru, India
| | - Pornchai Rachtanapun
- School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai, Thailand
- Cluster of Agro Bio-Circular-Green Industry (Agro BCG), Chiang Mai University, Chiang Mai, Thailand
| | - Devananda Devegowda
- Centre of Excellence in Molecular Biology and Regenerative Medicine (CEMR), Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education and Research (JSSAHER), Mysuru, India
| | - Prasanna K Santhekadur
- Centre of Excellence in Molecular Biology and Regenerative Medicine (CEMR), Department of Biochemistry, JSS Medical College, JSS Academy of Higher Education and Research (JSSAHER), Mysuru, India
| | - Sarana Rose Sommano
- Cluster of Agro Bio-Circular-Green Industry (Agro BCG), Chiang Mai University, Chiang Mai, Thailand
- Department of Plant and Soil Sciences, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand
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Gundagurti B, Dasari P, Singh R. Association of Chlamydophila pneumoniae infection and hypertension during pregnancy - A case control study. Clin Exp Hypertens 2021; 43:793-799. [PMID: 34433341 DOI: 10.1080/10641963.2021.1969661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND The association of Chlamydophila pneumoniae infection with essential hypertension is known but its association with hypertension during pregnancy is controversial. Hence, this study aimed to explore the association of C. pneumoniae infection with hypertension during pregnancy. The objectives were to compare the presence of C. pneumoniae DNA in trophoblastic cells of placenta between hypertensive and normotensive pregnant women and to find out the presence of inflammatory marker (HSP-60) and the seropositivity (IgG and IgA) of C. pneumoniae in them. MATERIALS AND METHODS The study was conducted at a tertiary-care institute, in South-India between 2018 and 2020. Women with hypertension during pregnancy were study group (75) and normotensive pregnant women were control group (75). IgG and IgA antibodies, HSP-60 against C. pneumoniae were estimated by ELISA from 5 ml of venous blood. C. pneumoniae DNA was extracted from placental tissue after delivery and tested by RT-PCR. STATISTICAL ANALYSIS The association between C. pneumoniae DNA, seropositivity and hypertension was determined by student test and univariate regression analysis. RESULTS C. pneumoniae DNA was detected in the placenta of 29.3% with hypertension and none in controls and the odds was 6.5 (OR-6.5, CI 95%). HSP-60 was elevated in women with preeclampsia and not in gestational hypertension and controls. IgA was not detected and IgG was positive in 15.2% of women with preeclampsia. CONCLUSION There is a significant association between C. pneumoniae infection and hypertension during pregnancy and further studies are required to fulfil the Koch's postulates to prove or disprove it as a causative agent.
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Affiliation(s)
| | - Papa Dasari
- Department of Obstetrics and Gynaecology, JIPMER, Pondicherry, Pondicherry, India
| | - Rakesh Singh
- Department of Microbiology, JIPMER, Pondicherry, Pondicherry, India
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Sixt BS. Host cell death during infection with Chlamydia: a double-edged sword. FEMS Microbiol Rev 2021; 45:5902849. [PMID: 32897321 PMCID: PMC7794043 DOI: 10.1093/femsre/fuaa043] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/02/2020] [Indexed: 12/12/2022] Open
Abstract
The phylum Chlamydiae constitutes a group of obligate intracellular bacteria that infect a remarkably diverse range of host species. Some representatives are significant pathogens of clinical or veterinary importance. For instance, Chlamydia trachomatis is the leading infectious cause of blindness and the most common bacterial agent of sexually transmitted diseases. Chlamydiae are exceptionally dependent on their eukaryotic host cells as a consequence of their developmental biology. At the same time, host cell death is an integral part of the chlamydial infection cycle. It is therefore not surprising that the bacteria have evolved exquisite and versatile strategies to modulate host cell survival and death programs to their advantage. The recent introduction of tools for genetic modification of Chlamydia spp., in combination with our increasing awareness of the complexity of regulated cell death in eukaryotic cells, and in particular of its connections to cell-intrinsic immunity, has revived the interest in this virulence trait. However, recent advances also challenged long-standing assumptions and highlighted major knowledge gaps. This review summarizes current knowledge in the field and discusses possible directions for future research, which could lead us to a deeper understanding of Chlamydia's virulence strategies and may even inspire novel therapeutic approaches.
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Affiliation(s)
- Barbara S Sixt
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
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Mughal MJ, Kwok HF. Multidimensional role of bacteria in cancer: Mechanisms insight, diagnostic, preventive and therapeutic potential. Semin Cancer Biol 2021; 86:1026-1044. [PMID: 34119644 DOI: 10.1016/j.semcancer.2021.06.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/28/2021] [Accepted: 06/08/2021] [Indexed: 02/08/2023]
Abstract
The active role of bacteria in oncogenesis has long been a topic of debate. Although, it was speculated to be a transmissible cause of cancer as early as the 16th-century, yet the idea about the direct involvement of bacteria in cancer development has only been explored in recent decades. More recently, several studies have uncovered the mechanisms behind the carcinogenic potential of bacteria which are inflammation, immune evasion, pro-carcinogenic metabolite production, DNA damage and genomic instability. On the other side, the recent development on the understanding of tumor microenvironment and technological advancements has turned this enemy into an ally. Studies using bacteria for cancer treatment and detection have shown noticeable effects. Therapeutic abilities of bioengineered live bacteria such as high specificity, selective cytotoxicity to cancer cells, responsiveness to external signals and control after ingestion have helped to overcome the challenges faced by conventional cancer therapies and highlighted the bacterial based therapy as an ideal approach for cancer treatment. In this review, we have made an effort to compile substantial evidence to support the multidimensional role of bacteria in cancer. We have discussed the multifaceted role of bacteria in cancer by highlighting the wide impact of bacteria on different cancer types, their mechanisms of actions in inducing carcinogenicity, followed by the diagnostic and therapeutic potential of bacteria in cancers. Moreover, we have also highlighted the existing gaps in the knowledge of the association between bacteria and cancer as well as the limitation and advantage of bacteria-based therapies in cancer. A better understanding of these multidimensional roles of bacteria in cancer can open up the new doorways to develop early detection strategies, prevent cancer, and develop therapeutic tactics to cure this devastating disease.
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Affiliation(s)
- Muhammad Jameel Mughal
- Cancer Centre, Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau
| | - Hang Fai Kwok
- Cancer Centre, Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau; MOE Frontiers Science Center for Precision Oncology, University of Macau, Avenida de Universidade, Taipa, Macau.
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Chen H, Wen Y, Li Z. Clear Victory for Chlamydia: The Subversion of Host Innate Immunity. Front Microbiol 2019; 10:1412. [PMID: 31333596 PMCID: PMC6619438 DOI: 10.3389/fmicb.2019.01412] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 06/05/2019] [Indexed: 12/14/2022] Open
Abstract
As obligate intracellular bacterial pathogens, members of the Chlamydia genera are the pivotal triggers for a wide range of infections, which can lead to blinding trachoma, pelvic inflammation, and respiratory diseases. Because of their restricted parasitism inside eukaryotic cells, the pathogens have to develop multiple strategies for adaptation with the hostile intracellular environment—intrinsically present in all host cells—to survive. The strategies that are brought into play at different stages of chlamydial development mainly involve interfering with diverse innate immune responses, such as innate immune recognition, inflammation, apoptosis, autophagy, as well as the manipulation of innate immune cells to serve as potential niches for chlamydial replication. This review will focus on the innate immune responses against chlamydial infection, highlighting the underlying molecular mechanisms used by the Chlamydia spp. to counteract host innate immune defenses. Insights into these subtle pathogenic mechanisms not only provide a rationale for the augmentation of immune responses against chlamydial infection but also open avenues for further investigation of the molecular mechanisms driving the survival of these clinically important pathogens in host innate immunity.
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Affiliation(s)
- Hongliang Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Department of Clinical Microbiology Laboratory, Chenzhou No. 1 People's Hospital, Chenzhou, China
| | - Yating Wen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Zhongyu Li
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
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Giebel AM, Hu S, Rajaram K, Finethy R, Toh E, Brothwell JA, Morrison SG, Suchland RJ, Stein BD, Coers J, Morrison RP, Nelson DE. Genetic Screen in Chlamydia muridarum Reveals Role for an Interferon-Induced Host Cell Death Program in Antimicrobial Inclusion Rupture. mBio 2019; 10:e00385-19. [PMID: 30967464 PMCID: PMC6456753 DOI: 10.1128/mbio.00385-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 02/27/2019] [Indexed: 01/02/2023] Open
Abstract
Interferon-regulated immune defenses protect mammals from pathogenically diverse obligate intracellular bacterial pathogens of the genus Chlamydia Interferon gamma (IFN-γ) is especially important in controlling the virulence of Chlamydia species and thus impacts the modeling of human chlamydial infection and disease in mice. How IFN-γ contributes to cell-autonomous defenses against Chlamydia species and how these pathogens evade IFN-γ-mediated immunity in their natural hosts are not well understood. We conducted a genetic screen which identified 31 IFN-γ-sensitive (Igs) mutants of the mouse model pathogen Chlamydia muridarum Genetic suppressor analysis and lateral gene transfer were used to map the phenotype of one of these mutants, Igs4, to a missense mutation in a putative chlamydial inclusion membrane protein, TC0574. We observed the lytic destruction of Igs4-occupied inclusions and accompanying host cell death in response to IFN-γ priming or various proapoptotic stimuli. However, Igs4 was insensitive to IFN-γ-regulated cell-autonomous defenses previously implicated in anti-Chlamydia trachomatis host defense in mice. Igs4 inclusion integrity was restored by caspase inhibitors, indicating that the IFN-γ-mediated destruction of Igs4 inclusions is dependent upon the function of caspases or related prodeath cysteine proteases. We further demonstrated that the Igs4 mutant is immune restricted in an IFN-γ-dependent manner in a mouse infection model, thereby implicating IFN-γ-mediated inclusion destruction and host cell death as potent in vivo host defense mechanisms to which wild-type C. muridarum is resistant. Overall, our results suggest that C. muridarum evolved resistance mechanisms to counter IFN-γ-elicited programmed cell death and the associated destruction of intravacuolar pathogens.IMPORTANCE Multiple obligatory intracellular bacteria in the genus Chlamydia are important pathogens. In humans, strains of C. trachomatis cause trachoma, chlamydia, and lymphogranuloma venereum. These diseases are all associated with extended courses of infection and reinfection that likely reflect the ability of chlamydiae to evade various aspects of host immune responses. Interferon-stimulated genes, driven in part by the cytokine interferon gamma, restrict the host range of various Chlamydia species, but how these pathogens evade interferon-stimulated genes in their definitive host is poorly understood. Various Chlamydia species can inhibit death of their host cells and may have evolved this strategy to evade prodeath signals elicited by host immune responses. We present evidence that chlamydia-induced programmed cell death resistance evolved to counter interferon- and immune-mediated killing of Chlamydia-infected cells.
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Affiliation(s)
- Amanda M Giebel
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Shuai Hu
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Krithika Rajaram
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ryan Finethy
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Evelyn Toh
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Julie A Brothwell
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sandra G Morrison
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Robert J Suchland
- Division of Allergy and Infectious Disease, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Barry D Stein
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Immunology, Duke University Medical Center, Durham, North Carolina, USA
| | - Richard P Morrison
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - David E Nelson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Chlamydia trachomatis ct143 stimulates secretion of proinflammatory cytokines via activating the p38/MAPK signal pathway in THP-1 cells. Mol Immunol 2018; 105:233-239. [PMID: 30554084 DOI: 10.1016/j.molimm.2018.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 11/03/2018] [Accepted: 12/09/2018] [Indexed: 01/22/2023]
Abstract
Chlamydia trachomatis (Ct) infections can cause bacterial sexually-transmitted and preventable blindness. The Ct infections induced excessive cytokines generation which attributed to pathologic changes in host cells. However, the precise mechanisms of Ct-induced cytokines production are still unclear.CT143 protein was identified as a novel Ct specific protein with high immunogenicity. In the present study. The CT143 fusion protein was recombined and purified. The mice immune serum was prepared by immunizing BALB/c mice with the purified fusion protein. The specificity of the antibody was confirmed using Immunoblotting. Indirect immunoflurescence assay (IFA) and Immunoblotting assays were performed to detect the temporal and spatial characteristics of CT143 in Ct infected cells. ELISA was performed to analyze the secretion of proinflammatory cytokines IL-1β, IL-8 and TNF-α by human macrophages under the stimulation of CT143 protein. Finally, the involvement of p38 signaling in CT143-induced cytokine secretion was validated. CT143 protein was located in the inclusion body and represented an Elementary body (EB)-related protein, which may be encoded by the mid- and late-stage expressing genes. CT143 protein could stimulate the secretion of inflammatory cytokines in macrophages which differentiated from THP-1 This induction may be mediated by the activation of p38 signaling. In summary, CT143 protein is involved in inflammatory processes during Ct infection.
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Chlamydia trachomatis fails to protect its growth niche against pro-apoptotic insults. Cell Death Differ 2018; 26:1485-1500. [PMID: 30375511 PMCID: PMC6748135 DOI: 10.1038/s41418-018-0224-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/20/2018] [Accepted: 10/02/2018] [Indexed: 12/11/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterial agent responsible for ocular infections and sexually transmitted diseases. It has been postulated that Chlamydia inhibits apoptosis in host cells to maintain an intact replicative niche until sufficient infectious progeny can be generated. Here we report that, while cells infected with C. trachomatis are protected from apoptosis at early and mid-stages of infection, they remain susceptible to the induction of other cell death modalities. By monitoring the fate of infected cells by time-lapse video microscopy and by analyzing host plasma membrane integrity and the activity of caspases, we determined that C. trachomatis-infected cells exposed to pro-apoptotic stimuli predominately died by a mechanism resembling necrosis. This necrotic death of infected cells occurred with kinetics similar to the induction of apoptosis in uninfected cells, indicating that C. trachomatis fails to considerably prolong the lifespan of its host cell when exposed to pro-apoptotic insults. Inhibitors of bacterial protein synthesis partially blocked necrotic death of infected cells, suggesting that the switch from apoptosis to necrosis relies on an active contribution of the bacteria. Tumor necrosis factor alpha (TNF-α)-mediated induction of necrosis in cells infected with C. trachomatis was not dependent on canonical regulators of necroptosis, such as RIPK1, RIPK3, or MLKL, yet was blocked by inhibition or depletion of CASP8. These results suggest that alternative signaling pathways regulate necrotic death in the context of C. trachomatis infections. Finally, consistent with the inability of C. trachomatis to preserve host cell viability, necrosis resulting from pro-apoptotic conditions significantly impaired production of infectious progeny. Taken together, our findings suggest that Chlamydia’s anti-apoptotic activities are not sufficient to protect the pathogen’s replicative niche.
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Chlamydial plasmid-encoded virulence factor Pgp3 interacts with human cathelicidin peptide LL-37 to modulate immune response. Microbes Infect 2018; 21:50-55. [PMID: 29959096 DOI: 10.1016/j.micinf.2018.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/17/2018] [Accepted: 06/19/2018] [Indexed: 11/23/2022]
Abstract
We have previously reported that Chlamydia trachomatis plasmid-encoded Pgp3 is able to neutralize anti-chlamydial activity of human cathelicidin peptide LL-37 by binding to and forming stable complex with LL-37. Besides its microbicidal activity, LL-37 also modulates immune response, including inducing cytokine/chemokine production in fibroblast/epithelial cells and recruitment of inflammatory cells. We now report that LL-37 was significantly induced in the genital tracts of women diagnosed positive for C. trachomatis. Both the LL-37-stimulated IL-6/8 production in human endometrial epithelial cells and the LL-37-induced neutrophil chemotaxis were blocked by Pgp3. Interestingly, although Pgp3 itself alone could not induce cytokines in epithelial cell cells, it did so in neutrophils. Importantly, the Pgp3 proinflammatory activity in neutrophils was significantly enhanced by forming complex with LL-37 although LL-37 alone failed to induce cytokine production in neutrophils. Thus, we have demonstrated that Pgp3 can modulate the proinflammatory activities of LL-37 on epithelial cells by forming stable complex with LL-37 but the Pgp3's own proinflammatory activity on myeloid cells is enhanced by forming the same complex. We hypothesize that Chlamydia may use Pgp3 to both block detrimental inflammation for improving its own fitness in the genital tract epithelial tissue and activate myeloid cell-mediated inflammation for potentially promoting spreading between the hosts, the latter of which may inevitably contribute to the development of inflammatory sequelae such as tubal fibrosis.
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Relación entre la infección por el virus del papiloma humano y Chlamydia trachomatis. CLINICA E INVESTIGACION EN GINECOLOGIA Y OBSTETRICIA 2017. [DOI: 10.1016/j.gine.2016.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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De Filippis A, Buommino E, Domenico MD, Feola A, Brunetti-Pierri R, Rizzo A. Chlamydia trachomatis induces an upregulation of molecular biomarkers podoplanin, Wilms' tumour gene 1, osteopontin and inflammatory cytokines in human mesothelial cells. MICROBIOLOGY-SGM 2017; 163:654-663. [PMID: 28535856 DOI: 10.1099/mic.0.000465] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Chlamydia trachomatis is the most prevalent infection of the genital tract in women worldwide. C. trachomatis has a tendency to cause persistent infection and induce a state of chronic inflammation, which has been reported to play a role in carcinogenesis. We report that persistent C. trachomatis infection increases the expression of inflammatory tumour cytokines and upregulates molecular biomarkers such as podoplanin, Wilms' tumour gene 1 and osteopontin in primary cultures of mesothelial cells (Mes1) and human mesothelioma cells (NCI). Infection experiments showed that Mes1 and NCI supported the growth of C. trachomatisin vitro, and at an m.o.i. of 4, the inclusion-forming units/cell showed many intracellular inclusion bodies after 3 days of infection. However, after 7 days of incubation, increased proliferative and invasive activity was also observed in Mes1 cells, which was more evident after 14 days of incubation. ELISA analysis revealed an increase in vascular endothelial growth factor, IL-6, IL-8, and TNF-α release in Mes1 cells infected for a longer period (14 days). Finally, real-time PCR analysis revealed a strong induction of podoplanin, Wilms' tumour gene 1 and osteopontin gene expression in infected Mes1 cells. The aim of the present study was to investigate the inflammatory response elicited by C. trachomatis persistent infection and the role played by inflammation in cell proliferation, secretion of proinflammatory cytokines and molecular biomarkers of cancer. The results of this study suggest that increased molecular biomarkers of cancer by persistent inflammation from C. trachomatis infection might support cellular transformation, thus increasing the risk of cancer.
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Affiliation(s)
- Anna De Filippis
- Department of Experimental Medicine, Section of Microbiology and Clinical Microbiology, Faculty of Medicine and Surgery - Second University of Naples, Via Santa Maria di Costantinopoli, 16 - 80138 Naples, Italy
| | - Elisabetta Buommino
- Department of Experimental Medicine, Section of Microbiology and Clinical Microbiology, Faculty of Medicine and Surgery - Second University of Naples, Via Santa Maria di Costantinopoli, 16 - 80138 Naples, Italy
| | - Marina Di Domenico
- Department of Biochemistry, Biophysics and General Pathology - Second University of Naples, Via Santa Maria di Costantinopoli, 16 - 80138 Naples, Italy
| | - Antonia Feola
- Department of Biochemistry, Biophysics and General Pathology - Second University of Naples, Via Santa Maria di Costantinopoli, 16 - 80138 Naples, Italy
| | - Raffaella Brunetti-Pierri
- Multidisciplinary Department of Medical-Surgical and Dental Specialties - Second University of Naples, Via Pansini, 5 - 80131 Naples, Italy
| | - Antonietta Rizzo
- Department of Experimental Medicine, Section of Microbiology and Clinical Microbiology, Faculty of Medicine and Surgery - Second University of Naples, Via Santa Maria di Costantinopoli, 16 - 80138 Naples, Italy
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16
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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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Jiang P, Du W, Xiong Y, Lv Y, Feng J, Zhu S, Xue X, Chen S, Zhang L. Hepatitis B virus core antigen as a carrier for Chlamydia trachomatis MOMP multi-epitope peptide enhances protection against genital chlamydial infection. Oncotarget 2016; 6:43281-92. [PMID: 26657117 PMCID: PMC4791232 DOI: 10.18632/oncotarget.6533] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/26/2015] [Indexed: 12/26/2022] Open
Abstract
Chlamydia trachomatis (Ct) is the leading cause of sexually transmitted diseases worldwide. There is no safe and effective vaccine to control the spread of Ct. In development of Ct vaccine, selection of appropriate candidate antigens and an effective delivery system may be the main challenges. Multi-epitope of major outer membrane protein (MOMPm) is the most suitable candidate for a Ct vaccine, while hepatitis B virus core antigen (HBcAg) has unique advantages as vaccine delivery system. Therefore, in this study, we evaluated the immunogenicity and protective immune response of a novel candidate vaccine in a murine model of chlamydial genital infection. This candidate vaccine comprises MOMPm peptide delivered with HBcAg. Our results of Ct-specific serum IgG and secretory IgA assay, cytokine assay, and cytotoxic T-lymphocyte assay revealed that immunogenicity of the candidate vaccine was much better than that of the corresponding synthetic MOMPm peptide. Furthermore, the protective effect of the candidate vaccine was also shown much better than that of the synthetic peptide by calculating the isolation of Chlamydia from vaginal swabs and histopathological analysis. Taken together, our results indicate that HBcAg carrying Ct MOMPm could be an effective immune prophylactic for chlamydial infection.
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Affiliation(s)
- Pengfei Jiang
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
| | - Wangqi Du
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
| | - Yirong Xiong
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
| | - Yan Lv
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
| | - Juan Feng
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
| | - Shanli Zhu
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
| | - Xiangyang Xue
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
| | - Shao Chen
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
| | - Lifang Zhang
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, P. R. China
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Messinger JE, Nelton E, Feeney C, Gondek DC. Chlamydia Infection Across Host Species Boundaries Promotes Distinct Sets of Transcribed Anti-Apoptotic Factors. Front Cell Infect Microbiol 2015; 5:96. [PMID: 26779446 PMCID: PMC4688367 DOI: 10.3389/fcimb.2015.00096] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 12/07/2015] [Indexed: 12/31/2022] Open
Abstract
Chlamydiae, obligate intracellular bacteria, cause significant human and veterinary associated diseases. Having emerged an estimated 700-million years ago, these bacteria have twice adapted to humans as a host species, causing sexually transmitted infection (C. trachomatis) and respiratory associated disease (C. pneumoniae). The principle mechanism of host cell defense against these intracellular bacteria is the induction of cell death via apoptosis. However, in the "arms race" of co-evolution, Chlamydiae have developed mechanisms to promote cell viability and inhibit cell death. Herein we examine the impact of Chlamydiae infection across multiple host species on transcription of anti-apoptotic genes. We found mostly distinct patterns of gene expression (Mcl1 and cIAPs) elicited by each pathogen-host pair indicating Chlamydiae infection across host species boundaries does not induce a universally shared host response. Understanding species specific host-pathogen interactions is paramount to deciphering how potential pathogens become emerging diseases.
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Kalatova B, Jesenska R, Hlinka D, Dudas M. Tripolar mitosis in human cells and embryos: occurrence, pathophysiology and medical implications. Acta Histochem 2015; 117:111-25. [PMID: 25554607 DOI: 10.1016/j.acthis.2014.11.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/26/2014] [Accepted: 11/27/2014] [Indexed: 01/08/2023]
Abstract
Tripolar mitosis is a specific case of cell division driven by typical molecular mechanisms of mitosis, but resulting in three daughter cells instead of the usual count of two. Other variants of multipolar mitosis show even more mitotic poles and are relatively rare. In nature, this phenomenon was frequently observed or suspected in multiple common cancers, infected cells, the placenta, and in early human embryos with impaired pregnancy-yielding potential. Artificial causes include radiation and various toxins. Here we combine several pieces of the most recent evidence for the existence of different types of multipolar mitosis in preimplantation embryos together with a detailed review of the literature. The related molecular and cellular mechanisms are discussed, including the regulation of centriole duplication, mitotic spindle biology, centromere functions, cell cycle checkpoints, mitotic autocorrection mechanisms, and the related complicating factors in healthy and affected cells, including post-mitotic cell-cell fusion often associated with multipolar cell division. Clinical relevance for oncology and embryo selection in assisted reproduction is also briefly discussed in this context.
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20
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Enterococcus faecalis infection activates phosphatidylinositol 3-kinase signaling to block apoptotic cell death in macrophages. Infect Immun 2014; 82:5132-42. [PMID: 25267834 DOI: 10.1128/iai.02426-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Apoptosis is an intrinsic immune defense mechanism in the host response to microbial infection. Not surprisingly, many pathogens have evolved various strategies to manipulate this important pathway to benefit their own survival and dissemination in the host during infection. To our knowledge, no attempts have been made to explore the host cell survival signals modulated by the bacterium Enterococcus faecalis. Here, we show for the first time that during early stages of infection, internalized enterococci can prevent host cell (RAW264.7 cells, primary macrophages, and mouse embryonic fibroblasts [MEFs]) apoptosis induced by a wide spectrum of proapoptotic stimuli. Activation of caspase 3 and cleavage of the caspase 3 substrate poly(ADP-ribose) polymerase were inhibited in E. faecalis-infected cells, indicating that E. faecalis protects macrophages from apoptosis by inhibiting caspase 3 activation. This antiapoptotic activity in E. faecalis-infected cells was dependent on the activation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, which resulted in the increased expression of the antiapoptotic factor Bcl-2 and decreased expression of the proapoptotic factor Bax. Further analysis revealed that active E. faecalis physiology was important for inhibition of host cell apoptosis, and this feature seemed to be a strain-independent trait among E. faecalis isolates. Employing a mouse peritonitis model, we also determined that cells collected from the peritoneal lavage fluid of E. faecalis-infected mice showed reduced levels of apoptosis compared to cells from uninfected mice. These results show early modulation of apoptosis during infection and have important implications for enterococcal pathogenesis.
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Bao X, Gylfe A, Sturdevant GL, Gong Z, Xu S, Caldwell HD, Elofsson M, Fan H. Benzylidene acylhydrazides inhibit chlamydial growth in a type III secretion- and iron chelation-independent manner. J Bacteriol 2014; 196:2989-3001. [PMID: 24914180 PMCID: PMC4135636 DOI: 10.1128/jb.01677-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 06/04/2014] [Indexed: 11/20/2022] Open
Abstract
Chlamydiae are widespread Gram-negative pathogens of humans and animals. Salicylidene acylhydrazides, developed as inhibitors of type III secretion system (T3SS) in Yersinia spp., have an inhibitory effect on chlamydial infection. However, these inhibitors also have the capacity to chelate iron, and it is possible that their antichlamydial effects are caused by iron starvation. Therefore, we have explored the modification of salicylidene acylhydrazides with the goal to uncouple the antichlamydial effect from iron starvation. We discovered that benzylidene acylhydrazides, which cannot chelate iron, inhibit chlamydial growth. Biochemical and genetic analyses suggest that the derivative compounds inhibit chlamydiae through a T3SS-independent mechanism. Four single nucleotide polymorphisms were identified in a Chlamydia muridarum variant resistant to benzylidene acylhydrazides, but it may be necessary to segregate the mutations to differentiate their roles in the resistance phenotype. Benzylidene acylhydrazides are well tolerated by host cells and probiotic vaginal Lactobacillus species and are therefore of potential therapeutic value.
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Affiliation(s)
- Xiaofeng Bao
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, USA Department of Pharmacology, Nantong University School of Pharmacy, Nantong, People's Republic of China
| | - Asa Gylfe
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Gail L Sturdevant
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Zheng Gong
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Shuang Xu
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Harlan D Caldwell
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | | | - Huizhou Fan
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
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22
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Jensen KE, Thomsen LT, Schmiedel S, Frederiksen K, Norrild B, van den Brule A, Iftner T, Kjær SK. Chlamydia trachomatis and risk of cervical intraepithelial neoplasia grade 3 or worse in women with persistent human papillomavirus infection: a cohort study. Sex Transm Infect 2014; 90:550-5. [PMID: 24728044 DOI: 10.1136/sextrans-2013-051431] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES Some studies suggest that Chlamydia trachomatis (CT) enhances cervical carcinogenesis; however, a possible confounding effect of persistent human papillomavirus (HPV) infection was not addressed. We examined the potential role of CT infection in the development of subsequent cervical intraepithelial neoplasia grade 3 or worse (CIN3+) in women with prevalent HPV infection and in a subgroup of women with persistent HPV infection. METHODS Participants in this population-based cohort study underwent a structured interview, including history of CT infection, and subsequently cervical exfoliated cells were obtained for HPV DNA and CT DNA testing. Women with high-risk HPV DNA infection and no prevalent cervical disease constituted the overall study population (n=1390). A subgroup of women with persistent HPV infection (n=320) was also identified. All women were passively followed for development of cervical lesions in the national Pathology Data Bank. HRs and 95% CIs for CIN3+ during follow-up (up to 19 years) were estimated in an accelerated failure time model. RESULTS Women who reported more than one CT infection had a statistically significantly increased risk of CIN3+ (high-risk HPV-positive, HR=2.51, 95% CI 1.44 to 4.37) (persistent HPV infection, HR=3.65, 95% CI 1.53 to 8.70). We found no association between CT DNA and subsequent risk of CIN3+ among women who were HPV-positive or had a persistent HPV infection at baseline. CONCLUSIONS Repeated CT infections increased the risk of CIN3+ among women with prevalent as well as persistent high-risk HPV infection.
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Affiliation(s)
- Kirsten E Jensen
- Unit of Virus, Lifestyle, and Genes, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Louise T Thomsen
- Unit of Virus, Lifestyle, and Genes, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Sven Schmiedel
- Unit of Statistics, Bioinformatics and Registries, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Kirsten Frederiksen
- Unit of Statistics, Bioinformatics and Registries, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Bodil Norrild
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Adriaan van den Brule
- Laboratory for Molecular Diagnostics, Department of Medical Microbiology and Pathology, Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands
| | - Thomas Iftner
- Medical Virology, Section of Experimental Virology, University Hospital of Tübingen, Tübingen, Germany
| | - Susanne K Kjær
- Unit of Virus, Lifestyle, and Genes, Danish Cancer Society Research Center, Copenhagen, Denmark Gynecologic Clinic, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Zhu S, Feng Y, Rao P, Xue X, Chen S, Li W, Zhu G, Zhang L. Hepatitis B virus surface antigen as delivery vector can enhance Chlamydia trachomatis MOMP multi-epitope immune response in mice. Appl Microbiol Biotechnol 2014; 98:4107-17. [PMID: 24458565 DOI: 10.1007/s00253-014-5517-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/30/2013] [Accepted: 01/03/2014] [Indexed: 11/27/2022]
Abstract
Chlamydia trachomatis is the leading cause of sexually transmitted infections worldwide. There is currently no commercially available vaccine against C. trachomatis. Major outer membrane protein (MOMP) of C. trachomatis is considered to be an ideal candidate for prophylactic vaccine. We designed a MOMP multi-epitope containing T- and B-cell epitope-rich peptides and developed hepatitis B surface antigen (HBsAg) as antigen delivery vehicle. In order to study the immunogenicity and efficacy of the candidate vaccine in a murine model of chlamydial genital infection, we engineered a recombinant plasmid expressing HBsAg and MOMP multi-epitope genes. Results of reverse transcription polymerase chain reaction and immunofluorescence assay revealed successful expression of the recombinant HBsAg/MOMP multi-epitope gene at both the transcription and translation levels. Intramuscular administration in mice was able to elicit not only antibodies against Chlamydia and HBsAg but also cytotoxic T lymphocyte activity against Chlamydia. In addition, mice inoculated with the rHBsAg were highly resistant to C. trachomatis genital infection. The rHBsAg DNA with MOMP multi-epitope appended at the C terminus of the HBsAg stimulated a stronger immune response and protective response than that appended at the N terminus. Together, our results suggested that use of a recombinant HBsAg encoding the MOMP multi-epitope could be a powerful approach to developing a safe and immunogenic C. trachomatis vaccine.
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Affiliation(s)
- Shanli Zhu
- Department of Microbiology and Immunology, Wenzhou Medical University, Wenzhou, 325000, China,
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Jayaram A, Orfanelli T, Doulaveris G, Linhares IM, Ledger WJ, Witkin SS. Autophagy and female genital tract infections: new insights and research directions. BJOG 2014; 121:801-8. [PMID: 24506514 DOI: 10.1111/1471-0528.12523] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2013] [Indexed: 12/17/2022]
Abstract
Autophagy is a highly conserved process by which defective organelles, non-functional proteins, and intracellular microorganisms become sequestered within structures called autophagosomes, which fuse with lysosomes and the engulfed components are degraded by lysosomal enzymes. In microbial autophagy degraded peptides are used to induce antigen-specific acquired immunity. Viruses, bacteria, fungi, and protozoa have developed strategies to subvert autophagy and/or to use this process to promote their replication and persistence. This review details the mechanisms by which microorganisms that infect the female genital tract and/or are detrimental to pregnancy interact with this host defence mechanism. Based on an understanding of autophagy-related pathological mechanisms, we propose new avenues for research to more effectively prevent and/or treat these infectious diseases.
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Affiliation(s)
- A Jayaram
- Division of Immunology and Infectious Diseases, Department of Obstetrics and Gynecology, Weill Cornell Medical College, New York, NY, USA
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Chlamydia trachomatis-infected epithelial cells and fibroblasts retain the ability to express surface-presented major histocompatibility complex class I molecules. Infect Immun 2013; 82:993-1006. [PMID: 24343651 DOI: 10.1128/iai.01473-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The obligate intracellular bacterial pathogen Chlamydia trachomatis is the causative agent of a variety of infectious diseases such as trachoma and sexually transmitted diseases. In infected target cells, C. trachomatis replicates within parasitophorous vacuoles and expresses the protease-like activity factor CPAF. Previous studies have suggested that CPAF degrades the host transcription factors RFX5 and NF-κB p65, which are involved in the regulation of constitutive and inducible expression of major histocompatibility complex class I (MHC I). It was speculated that Chlamydia suppresses the surface presentation of MHC I in order to evade an effective immune response. Nevertheless, a recent study suggested that RFX5 and NF-κB p65 may not serve as target substrates for CPAF-mediated degradation, raising concerns about the proposed MHC I subversion by Chlamydia. Hence, we investigated the direct influence of Chlamydia on MHC I expression and surface presentation in infected host cells. By using nine different human cells and cell lines infected with C. trachomatis (serovar D or LGV2), we demonstrate that chlamydial infection does not interfere with expression, maturation, transport, and surface presentation of MHC I, suggesting functional antigen processing in bacterium-infected cells. Our findings provide novel insights into the interaction of chlamydiae with their host cells and should be taken into consideration for the design of future therapies and vaccines.
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Ding H, Gong S, Tian Y, Yang Z, Brunham R, Zhong G. Transformation of sexually transmitted infection-causing serovars of chlamydia trachomatis using Blasticidin for selection. PLoS One 2013; 8:e80534. [PMID: 24303023 PMCID: PMC3841219 DOI: 10.1371/journal.pone.0080534] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/14/2013] [Indexed: 01/06/2023] Open
Abstract
Plasmid-free Chlamydia trachomatis serovar L2 organisms have been transformed with chlamydial plasmid-based shuttle vectors pGFP::SW2 and pBRCT using β-lactamase as a selectable marker. However, the recommendation of amoxicillin, a β-lactam antibiotics, as one of the choices for treating pregnant women with cervicitis due to C. trachomatis infection has made the existing shuttle vectors unsuitable for transforming sexually transmitted infection (STI)-causing serovars of C. trachomatis. Thus, in the current study, we modified the pGFP::SW2 plasmid by fusing a blasticidin S deaminase gene to the GFP gene to establish blasticidin resistance as a selectable marker and replacing the β-lactamase gene with the Sh ble gene to eliminate the penicillin resistance. The new vector termed pGFPBSD/Z::SW2 was used for transforming plasmid-free C. trachomatis serovar D organisms. Using blasticidin for selection, stable transformants were obtained. The GFP-BSD fusion protein was detected in cultures infected with the pGFPBSD/Z::SW2-trasnformed serovar D organisms. The transformation restored the plasmid property to the plasmid-free serovar D organisms. Thus, we have successfully modified the pGFP::SW2 transformation system for studying the biology and pathogenesis of other STI-causing serovars of C. trachomatis.
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Affiliation(s)
- Honglei Ding
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Siqi Gong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Yingxin Tian
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Zhangsheng Yang
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Robert Brunham
- BC Centre for Disease Control, University of British Columbia, Vancouver, British Columbia, Canada
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
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Lei L, Dong X, Li Z, Zhong G. Identification of a novel nuclear localization signal sequence in Chlamydia trachomatis-secreted hypothetical protein CT311. PLoS One 2013; 8:e64529. [PMID: 23717625 PMCID: PMC3662721 DOI: 10.1371/journal.pone.0064529] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 04/16/2013] [Indexed: 12/03/2022] Open
Abstract
We previously reported that Chlamydia trachomatis hypothetical protein CT311 was secreted out of chlamydial inclusion and into host cell cytosol. We now found that CT311 further entered host cell nucleus at the late stage of infection and continued to accumulate in the nucleus of C. trachomatis-infected cells. When CT311 was expressed via a transgene in mammalian cells, CT311 protein was exclusively detected in the nucleus, suggesting that CT311 by itself is sufficient for nuclear targeting. However, preexisting nuclear CT311 did not affect subsequent chlamydial infection. Using deletion constructs, we mapped a nuclear localization signal sequence of CT311 to residues 21 to 63 (21AVEGKPLSRAAQLRERRKDLHVSGKPSPRYALKKRALEAKKNK63). This sequence was sufficient for targeting a heterologous protein into mammalian cell nucleus and it contains two independent clusters of basic residues (34RERRK38 and 53KKRALEAKKNK63 respectively). Deletion or alanine substitution of the basic residues in either cluster led to loss of nuclear targeting activity, suggesting that both clusters are critical for the nuclear targeting function. These observations have demonstrated that the hypothetical protein CT311 possesses a novel nuclear localization signal sequence with dual modules of basic residues for targeting host cell nucleus during Chlamydia trachomatis infection.
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Affiliation(s)
- Lei Lei
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Xiaohua Dong
- Department of Pharmacology, School of Pharmacy, Hebei Northern University, Zhangjiakou, Hebei, P. R. China
| | - Zhongyu Li
- Department of Microbiology, University of South China, Hengyang, Hunan, P. R. China
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
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Zhou H, Huang Q, Li Z, Wu Y, Xie X, Ma K, Cao W, Zhou Z, Lu C, Zhong G. PORF5 plasmid protein of Chlamydia trachomatis induces MAPK-mediated pro-inflammatory cytokines via TLR2 activation in THP-1 cells. SCIENCE CHINA-LIFE SCIENCES 2013; 56:460-6. [PMID: 23546865 DOI: 10.1007/s11427-013-4470-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 03/13/2013] [Indexed: 11/28/2022]
Abstract
Infection with Chlamydia trachomatis induces inflammatory pathologies in the urogenital tract that can lead to infertility and ectopic pregnancy. Pathogenesis of infection has been mostly attributed to excessive cytokine production. However, precise mechanisms on how C. trachomatis triggers this production, and which protein(s) stimulate inflammatory cytokines remains unknown. In the present study, the C. trachomatis pORF5 protein induced tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-8 (IL-8) in dose- and time-dependent manners in the THP-1 human monocyte cell line. We found that intracellular p38/mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK)/MAPK signaling pathways were required for the induction of TNF-α, IL-1β and IL-8. Blockade of toll-like receptor 2 (TLR2) signaling reduced induction levels of TNF-α, IL-8 and IL-1β. We concluded that the C. trachomatis pORF5 protein might contribute to the inflammatory processes associated with chlamydial infections.
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Affiliation(s)
- Hui Zhou
- Pathogenic Biology Institute, University of South China, Hengyang 421001, China
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Alibek K, Karatayeva N, Bekniyazov I. The role of infectious agents in urogenital cancers. Infect Agent Cancer 2012; 7:35. [PMID: 23198689 PMCID: PMC3626724 DOI: 10.1186/1750-9378-7-35] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 11/20/2012] [Indexed: 02/07/2023] Open
Abstract
Since the late 1990s, infectious agents have been thought to play a role in the pathogenesis of approximately 15% of cancers. It is now widely accepted that infection of stomach tissue with the bacteria Helicobacter pylori is an important cause of stomach adenocarcinoma. In addition, oncogenic viruses, such as papilloma viruses, herpes viruses, and hepadnaviruses are strongly associated with increased risk of cervical cancer, lymphomas, liver cancer, amongst others. However, in the scientific community the percentage of cancers caused by pathogens is believed to be far higher than 15%. A significant volume of data collected to date show an association between infectious agents and urogenital cancers. These agents include Chlamydia trachomatis, Neisseria gonorrhoea, Mycoplasma genitalium and certain viruses that have been implicated in ovarian cancer. Other pathogens include the hepatitis C and Epstein-Barr viruses, which are potentially involved in kidney cancer. In addition, infections with Schistosoma haematobium, the human papillomavirus, and human polyomaviruses are strongly associated with an increased risk of urinary bladder cancer. This article reviews publications available to date on the role of infectious agents in urogenital cancers. A greater understanding of the role of such agents could aid the identification of novel methods of urogenital cancer treatment.
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Affiliation(s)
- Kenneth Alibek
- Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana 010000, Kazakhstan
- Republican Scientific Center for Emergency Care, 3 Kerey and Zhanibek Khan Street, Astana 010000, Kazakhstan
| | - Nargis Karatayeva
- Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana 010000, Kazakhstan
| | - Ildar Bekniyazov
- Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana 010000, Kazakhstan
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Black LA, McLachlan AJ, Griffith JE, Higgins DP, Gillett A, Krockenberger MB, Govendir M. Pharmacokinetics of chloramphenicol following administration of intravenous and subcutaneous chloramphenicol sodium succinate, and subcutaneous chloramphenicol, to koalas (Phascolarctos cinereus). J Vet Pharmacol Ther 2012; 36:478-85. [PMID: 23157306 DOI: 10.1111/jvp.12024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 10/11/2012] [Indexed: 01/01/2023]
Abstract
Clinically normal koalas (n = 19) received a single dose of intravenous (i.v.) chloramphenicol sodium succinate (SS) (25 mg/kg; n = 6), subcutaneous (s.c.) chloramphenicol SS (60 mg/kg; n = 7) or s.c. chloramphenicol base (60 mg/kg; n = 6). Serial plasma samples were collected over 24-48 h, and chloramphenicol concentrations were determined using a validated high-performance liquid chromatography assay. The median (range) apparent clearance (CL/F) and elimination half-life (t(1/2)) of chloramphenicol after i.v. chloramphenicol SS administration were 0.52 (0.35-0.99) L/h/kg and 1.13 (0.76-1.40) h, respectively. Although the area under the concentration-time curve was comparable for the two s.c. formulations, the absorption rate-limited disposition of chloramphenicol base resulted in a lower median C(max) (2.52; range 0.75-6.80 μg/mL) and longer median tmax (8.00; range 4.00-12.00 h) than chloramphenicol SS (C(max) 20.37, range 13.88-25.15 μg/mL; t(max) 1.25, range 1.00-2.00 h). When these results were compared with susceptibility data for human Chlamydia isolates, the expected efficacy of the current chloramphenicol dosing regimen used in koalas to treat chlamydiosis remains uncertain and at odds with clinical observations.
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Affiliation(s)
- L A Black
- Faculty of Veterinary Science, The University of Sydney, NSW, Australia
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Chlamydia trachomatis antigens recognized in women with tubal factor infertility, normal fertility, and acute infection. Obstet Gynecol 2012; 119:1009-16. [PMID: 22525912 DOI: 10.1097/aog.0b013e3182519326] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To identify Chlamydia trachomatis antigens associated with tubal factor infertility and acute infection. METHODS A C trachomatis proteome array was used to compare antibody profiles among women with tubal factor infertility, normal fertility, and acute C trachomatis infection. RESULTS Thirteen immunodominant antigens reacted with 50% or more sera from all women (n=73). Six C trachomatis antigens were uniquely recognized in women with tubal factor infertility. Combining fragmentation of the six antigens with serum sample dilution, chlamydial antigens HSP60, CT376, CT557, and CT443 could discriminate between women with tubal factor infertility and women with normal fertility with a sensitivity of 63% (95% confidence interval [CI] 0.41-0.77) and specificity of 100% (95% CI 0.91-1), respectively. These antigens were designated as tubal factor infertility-associated antigens. However, these tubal factor antigens were unable to distinguish tubal factor infertility patients from those with acute infection. A combination of CT875 and CT147 distinguished women with acute infection from all other C trachomatis-exposed women with a detection sensitivity of 63% (95% CI 0.41-0.77) and specificity of 100% (95% CI 0.95-1), respectively. Thus, CT875 and CT147 were designated as acute infection-associated antigens. CONCLUSION A sequential screening of antibodies against panels of C trachomatis antigens can be used to identify women with tubal factor infertility and acute C trachomatis infection. LEVEL OF EVIDENCE II.
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Li Z, Lu C, Peng B, Zeng H, Zhou Z, Wu Y, Zhong G. Induction of protective immunity against Chlamydia muridarum intravaginal infection with a chlamydial glycogen phosphorylase. PLoS One 2012; 7:e32997. [PMID: 22427926 PMCID: PMC3299733 DOI: 10.1371/journal.pone.0032997] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 02/06/2012] [Indexed: 11/19/2022] Open
Abstract
We evaluated 7 C. muridarum ORFs for their ability to induce protection against chlamydial infection in a mouse intravaginal infection model. These antigens, although encoded in C. muridarum genome, are transcriptionally regulated by a cryptic plasmid that is known to contribute to C. muridarum pathogenesis. Of the 7 plasmid-regulated ORFs, the chlamydial glycogen phosphorylase or GlgP, when delivered into mice intramuscularly, induced the most pronounced protective immunity against C. muridarum intravaginal infection. The GlgP-immunized mice displayed a significant reduction in vaginal shedding of live organisms on day 14 after infection. The protection correlated well with a robust C. muridarum-specific antibody and a Th1-dominant T cell responses, which significantly reduced the severity but not overall incidence of hydrosalpinx. The GlgP-induced partial protection against upper genital tract pathology suggests that GlgP may be considered a component for a multi-subunit vaccine. These results have demonstrated that intramuscular immunization of mice with purified proteins can be used to identify vaccine antigens for preventing intravaginal infection with C. trachomatis in humans.
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Affiliation(s)
- Zhihong Li
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chunxue Lu
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Microbiology and Pathology, University of South China, Hengyang, Hunan, China
| | - Bo Peng
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Microbiology and Pathology, University of South China, Hengyang, Hunan, China
| | - Hao Zeng
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Zhiguan Zhou
- Department of Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yimou Wu
- Department of Microbiology and Pathology, University of South China, Hengyang, Hunan, China
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
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Sixt BS, Hiess B, König L, Horn M. Lack of effective anti-apoptotic activities restricts growth of Parachlamydiaceae in insect cells. PLoS One 2012; 7:e29565. [PMID: 22253735 PMCID: PMC3253803 DOI: 10.1371/journal.pone.0029565] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 11/30/2011] [Indexed: 12/02/2022] Open
Abstract
The fundamental role of programmed cell death in host defense is highlighted by the multitude of anti-apoptotic strategies evolved by various microbes, including the well-known obligate intracellular bacterial pathogens Chlamydia trachomatis and Chlamydia (Chlamydophila) pneumoniae. As inhibition of apoptosis is assumed to be essential for a successful infection of humans by these chlamydiae, we analyzed the anti-apoptotic capacity of close relatives that occur as symbionts of amoebae and might represent emerging pathogens. While Simkania negevensis was able to efficiently replicate within insect cells, which served as model for metazoan-derived host cells, the Parachlamydiaceae (Parachlamydia acanthamoebae and Protochlamydia amoebophila) displayed limited intracellular growth, yet these bacteria induced typical features of apoptotic cell death, including formation of apoptotic bodies, nuclear condensation, internucleosomal DNA fragmentation, and effector caspase activity. Induction of apoptosis was dependent on bacterial activity, but not bacterial de novo protein synthesis, and was detectable already at very early stages of infection. Experimental inhibition of host cell death greatly enhanced parachlamydial replication, suggesting that lack of potent anti-apoptotic activities in Parachlamydiaceae may represent an important factor compromising their ability to successfully infect non-protozoan hosts. These findings highlight the importance of the evolution of anti-apoptotic traits for the success of chlamydiae as pathogens of humans and animals.
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Affiliation(s)
- Barbara S. Sixt
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Birgit Hiess
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Lena König
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Matthias Horn
- Department of Microbial Ecology, University of Vienna, Vienna, Austria
- * E-mail:
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The Chlamydia protease CPAF regulates host and bacterial proteins to maintain pathogen vacuole integrity and promote virulence. Cell Host Microbe 2011; 10:21-32. [PMID: 21767809 DOI: 10.1016/j.chom.2011.06.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 06/02/2011] [Accepted: 06/24/2011] [Indexed: 11/23/2022]
Abstract
The obligate intracellular bacterial pathogen Chlamydia trachomatis injects numerous effector proteins into the epithelial cell cytoplasm to manipulate host functions important for bacterial survival. In addition, the bacterium secretes a serine protease, chlamydial protease-like activity factor (CPAF). Although several CPAF targets are reported, the significance of CPAF-mediated proteolysis is unclear due to the lack of specific CPAF inhibitors and the diversity of host targets. We report that CPAF also targets chlamydial effectors secreted early during the establishment of the pathogen-containing vacuole ("inclusion"). We designed a cell-permeable CPAF-specific inhibitory peptide and used it to determine that CPAF prevents superinfection by degrading early Chlamydia effectors translocated during entry into a preinfected cell. Prolonged CPAF inhibition leads to loss of inclusion integrity and caspase-1-dependent death of infected epithelial cells. Thus, CPAF functions in niche protection, inclusion integrity and pathogen survival, making the development of CPAF-specific protease inhibitors an attractive antichlamydial therapeutic strategy.
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35
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Lu C, Zeng H, Li Z, Lei L, Yeh IT, Wu Y, Zhong G. Protective immunity against mouse upper genital tract pathology correlates with high IFNγ but low IL-17 T cell and anti-secretion protein antibody responses induced by replicating chlamydial organisms in the airway. Vaccine 2011; 30:475-85. [PMID: 22079265 DOI: 10.1016/j.vaccine.2011.10.059] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 09/20/2011] [Accepted: 10/22/2011] [Indexed: 01/02/2023]
Abstract
To search for optimal immunization conditions for inducing protective immunity against upper genital tract pathologies caused by chlamydial intravaginal infection, we compared protection efficacy in mice immunized intranasally or intramuscularly with live or inactivated Chlamydia muridarum organisms. Mice immunized intranasally with live organisms developed strong protection against both vaginal shedding of infectious organisms and upper genital tract pathologies. The protection correlated with a robust antigen-specific T cell response with high IFNγ but low IL-17. Although a significant level of IL-5 was also detected, these mice maintained an overall Th1-dorminant immunity following immunization and challenge infection. On the contrary, mice immunized intranasally with inactivated organisms or intramuscularly with live or inactivated organisms produced high levels of IL-17 and still developed significant upper genital tract pathologies. High titers of antibodies against chlamydial secretion antigens were detected only in mice immunized intranasally with live organisms but not mice in other groups, suggesting that the intranasally inoculated live organisms were able to undergo replication and immune responses to the chlamydial secretion proteins may contribute to protective immunity. These observations have provided important information on how to develop subunit vaccines for inducing protective immunity against urogenital infection with Chlamydia trachomatis organisms.
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Affiliation(s)
- Chunxue Lu
- 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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Bao X, Pachikara ND, Oey CB, Balakrishnan A, Westblade LF, Tan M, Chase T, Nickels BE, Fan H. Non-coding nucleotides and amino acids near the active site regulate peptide deformylase expression and inhibitor susceptibility in Chlamydia trachomatis. MICROBIOLOGY-SGM 2011; 157:2569-2581. [PMID: 21719536 PMCID: PMC3352175 DOI: 10.1099/mic.0.049668-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Chlamydia trachomatis, an obligate intracellular bacterium, is a highly prevalent human pathogen. Hydroxamic-acid-based matrix metalloprotease inhibitors can effectively inhibit the pathogen both in vitro and in vivo, and have exhibited therapeutic potential. Here, we provide genome sequencing data indicating that peptide deformylase (PDF) is the sole target of the inhibitors in this organism. We further report molecular mechanisms that control chlamydial PDF (cPDF) expression and inhibition efficiency. In particular, we identify the σ66-dependent promoter that controls cPDF gene expression and demonstrate that point mutations in this promoter lead to resistance by increasing cPDF transcription. Furthermore, we show that substitution of two amino acids near the active site of the enzyme alters enzyme kinetics and protein stability.
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Affiliation(s)
- Xiaofeng Bao
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA
| | - Niseema D Pachikara
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA
| | - Christopher B Oey
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA
| | - Amit Balakrishnan
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA
| | - Lars F Westblade
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Ming Tan
- Department of Microbiology and Molecular Genetics, and Department of Medicine, University of California, Irvine, CA 92697, USA
| | - Theodore Chase
- Department of Biochemistry and Microbiology, School of Environmental and Biological Science, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Bryce E Nickels
- Department of Genetics and Waksman Institute, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Huizhou Fan
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA
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Lei L, Qi M, Budrys N, Schenken R, Zhong G. Localization of Chlamydia trachomatis hypothetical protein CT311 in host cell cytoplasm. Microb Pathog 2011; 51:101-9. [PMID: 21605656 DOI: 10.1016/j.micpath.2011.05.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 05/02/2011] [Accepted: 05/04/2011] [Indexed: 11/28/2022]
Abstract
The chlamydia-specific hypothetical protein CT311 was detected both inside and outside of the chlamydial inclusions in Chlamydia trachomatis-infected cells. The extra-inclusion CT311 molecules were distributed in the host cell cytoplasm with a pattern similar to that of CPAF, a known Chlamydia-secreted protease. The detection of CT311 was specific since the anti-CT311 antibody labeling was only removed by absorption with CT311 but not CPAF fusion proteins. In addition, both anti-CT311 and anti-CPAF antibodies only detected their corresponding endogenous proteins without cross-reacting with each other or any other antigens in the whole cell lysates of C. trachomatis-infected cells. Although both CT311 and CPAF proteins were first detected 12 h after infection, localization of CT311 into host cell cytosol was delayed until 24 h while CPAF secretion into host cell cytosol was already obvious by 18 h after infection. The host cell cytosolic localization of CT311 was further confirmed in human primary cells. CT311 was predicted to contain an N-terminal secretion signal sequence and the CT311 signal sequence directed secretion of PhoA into bacterial periplasmic region in a heterologous assay system, suggesting that a sec-dependent pathway may play a role in the secretion of CT311 into host cell cytosol. This hypothesis is further supported by the observation that secretion of CT311 in Chlamydia-infected cells was blocked by a C16 compound known to inhibit signal peptidase I. These findings have provided important molecular information for further understanding the C. trachomatis pathogenic mechanisms.
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Affiliation(s)
- Lei Lei
- 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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Knowlton AE, Brown HM, Richards TS, Andreolas LA, Patel RK, Grieshaber SS. Chlamydia trachomatis infection causes mitotic spindle pole defects independently from its effects on centrosome amplification. Traffic 2011; 12:854-66. [PMID: 21477082 DOI: 10.1111/j.1600-0854.2011.01204.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chlamydiae are Gram negative, obligate intracellular bacteria, and Chlamydia trachomatis is the etiologic agent of the most commonly reported sexually transmitted disease in the United States. Chlamydiae undergo a biphasic life cycle that takes place inside a parasitophorous vacuole termed an inclusion. Chlamydial infections have been epidemiologically linked to cervical cancer in patients previously infected by human papillomavirus (HPV). The inclusion associates very closely with host cell centrosomes, and this association is dependent upon the host motor protein dynein. We have previously reported that this interaction induces supernumerary centrosomes in infected cells, leading to multipolar mitotic spindles and inhibiting accurate chromosome segregation. Our findings demonstrate that chlamydial infection causes mitotic spindle defects independently of its effects on centrosome amplification. We show that chlamydial infection increases centrosome spread and inhibits the spindle assembly checkpoint delay to disrupt centrosome clustering. These data suggest that chlamydial infection exacerbates the consequences of centrosome amplification by inhibiting the cells' ability to suppress the effects of these defects on mitotic spindle organization. We hypothesize that these combined effects on mitotic spindle architecture identifies a possible mechanism for Chlamydia as a cofactor in cervical cancer formation.
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Affiliation(s)
- Andrea E Knowlton
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA
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Dehoux P, Flores R, Dauga C, Zhong G, Subtil A. Multi-genome identification and characterization of chlamydiae-specific type III secretion substrates: the Inc proteins. BMC Genomics 2011; 12:109. [PMID: 21324157 PMCID: PMC3048545 DOI: 10.1186/1471-2164-12-109] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 02/16/2011] [Indexed: 12/13/2022] Open
Abstract
Background Chlamydiae are obligate intracellular bacteria that multiply in a vacuolar compartment, the inclusion. Several chlamydial proteins containing a bilobal hydrophobic domain are translocated by a type III secretion (TTS) mechanism into the inclusion membrane. They form the family of Inc proteins, which is specific to this phylum. Based on their localization, Inc proteins likely play important roles in the interactions between the microbe and the host. In this paper we sought to identify and analyze, using bioinformatics tools, all putative Inc proteins in published chlamydial genomes, including an environmental species. Results Inc proteins contain at least one bilobal hydrophobic domain made of two transmembrane helices separated by a loop of less than 30 amino acids. Using bioinformatics tools we identified 537 putative Inc proteins across seven chlamydial proteomes. The amino-terminal segment of the putative Inc proteins was recognized as a functional TTS signal in 90% of the C. trachomatis and C. pneumoniae sequences tested, validating the data obtained in silico. We identified a macro domain in several putative Inc proteins, and observed that Inc proteins are enriched in segments predicted to form coiled coils. A surprisingly large proportion of the putative Inc proteins are not constitutively translocated to the inclusion membrane in culture conditions. Conclusions The Inc proteins represent 7 to 10% of each proteome and show a great degree of sequence diversity between species. The abundance of segments with a high probability for coiled coil conformation in Inc proteins support the hypothesis that they interact with host proteins. While the large majority of Inc proteins possess a functional TTS signal, less than half may be constitutively translocated to the inclusion surface in some species. This suggests the novel finding that translocation of Inc proteins may be regulated by as-yet undetermined mechanisms.
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Affiliation(s)
- Pierre Dehoux
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
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40
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Zhong G. Chlamydia trachomatis secretion of proteases for manipulating host signaling pathways. Front Microbiol 2011; 2:14. [PMID: 21687409 PMCID: PMC3109274 DOI: 10.3389/fmicb.2011.00014] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2011] [Accepted: 01/19/2011] [Indexed: 12/23/2022] Open
Abstract
The human pathogen Chlamydia trachomatis secretes numerous effectors into host cells in order to successfully establish and complete the intracellular growth cycle. Three C. trachomatis proteases [chlamydial proteasome/protease-like activity factor (CPAF), tail-specific protease (Tsp), and chlamydial high temperature requirement protein A (cHtrA)] have been localized in the cytosol of the infected cells either by direct immunofluorescence visualization or functional implication. Both CPAF and Tsp have been found to play important roles in C. trachomatis interactions with host cells although the cellular targets of cHtrA have not been identified. All three proteases contain a putative N-terminal signal sequence, suggesting that they may be secreted via a sec-dependent pathway. However, these proteases are also found in chlamydial organism-free vesicles in the lumen of the chlamydial inclusions before they are secreted into host cell cytosol, suggesting that these proteases may first be translocated into the periplasmic region via a sec-dependent pathway and then exported outside of the organisms via an outer membrane vesicles (OMVs) budding mechanism. The vesiculized proteases in the inclusion lumen can finally enter host cell cytosol via vesicle fusing with or passing through the inclusion membrane. Continuing identification and characterization of the C. trachomatis-secreted proteins (CtSPs) will not only promote our understanding of C. trachomatis pathogenic mechanisms but also allow us to gain novel insights into the OMV pathway, a well-known mechanism used by bacteria to export virulence factors although its mechanism remains elusive.
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Affiliation(s)
- Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio San Antonio, TX, USA
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Linhares IM, Witkin SS. Immunopathogenic consequences of Chlamydia trachomatis 60 kDa heat shock protein expression in the female reproductive tract. Cell Stress Chaperones 2010; 15:467-73. [PMID: 20182835 PMCID: PMC3006632 DOI: 10.1007/s12192-010-0171-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 01/19/2010] [Accepted: 01/21/2010] [Indexed: 01/26/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium that infects chiefly urogenital and ocular epithelial cells. In some infected women the microorganism migrates to the upper reproductive tract resulting in a chronic, but asymptomatic, infection. The immune response to this infection, production of interferon-gamma and pro-inflammatory cytokines, results in interruption of chlamydial intracellular replication. However, the Chlamydia remains viable and enters into a persistent state. In this form, most chlamydial genes are inactive. An exception is the gene coding for the 60 kDa heat shock protein (hsp60), which is synthesized in increased amounts and is released into the extracellular milieu. The chronic release of chlamydial hsp60 induces a local pro-inflammatory immune response in fallopian tube epithelia and results in scar formation and tubal occlusion. In addition, long-term exposure of the maternal immune system to the chlamydial hsp60 eventually results in the release of tolerance and generation of an immune response that recognizes regions of the chlamydial hsp60 that are also present in the human hsp60. Production of cross-reacting antibodies and cell-mediated immunity to the human hsp60 is detrimental to subsequent pregnancy outcome and may also possibly increase susceptibility to atherosclerosis, autoimmune disorders, or malignancies.
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Affiliation(s)
- Iara Moreno Linhares
- Division of Immunology and Infectious Diseases, Department of Obstetrics and Gynecology, Weill Cornell Medical College, 525 East 68th Street, P.O. Box 35, New York, NY 10065 USA
- Department of Gynecology, University of Sao Paulo Medical School and Hospital das Clinicas, Sao Paulo, Brazil
| | - Steven S. Witkin
- Division of Immunology and Infectious Diseases, Department of Obstetrics and Gynecology, Weill Cornell Medical College, 525 East 68th Street, P.O. Box 35, New York, NY 10065 USA
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42
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Wang J, Zhang Y, Lu C, Lei L, Yu P, Zhong G. A genome-wide profiling of the humoral immune response to Chlamydia trachomatis infection reveals vaccine candidate antigens expressed in humans. THE JOURNAL OF IMMUNOLOGY 2010; 185:1670-80. [PMID: 20581152 DOI: 10.4049/jimmunol.1001240] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A whole genome scale proteome array consisting of 908 open reading frames encoded in Chlamydia trachomatis genome and plasmid was used to profile anti-chlamydial Ab responses. A total of 719 chlamydial proteins was recognized by one or more antisera from 99 women urogenitally infected with C. trachomatis. Revealing such a large C. trachomatis ANTIGENome in humans might partially be attributed to the significantly improved detection sensitivity of the whole genome scale proteome array assay because both linear and conformation-dependent Abs were detected by the array assay. Twenty-seven of the 719 Ags were recognized by >or=50% antisera, thus designated as immunodominant Ags. Comparison of Ag profiles recognized by live chlamydial organism-infected versus dead organism-immunized hosts led to the identification of infection-dependent or in vivo expressed Ags. The infection-dependent Ags induced Abs only in live organism-infected, but not in dead organism-immunized hosts. Many of these Ags were highly expressed during replication, but only minimally packaged into the infectious elementary bodies. Because inactivated whole chlamydial organism-based vaccines failed to induce protection in humans, identification of the infection-dependent or in vivo expressed immunodominant Ags in humans should greatly facilitate the selection of promising chlamydial subunit vaccine candidates for further evaluation. This approach may also be applicable to other pathogens.
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Affiliation(s)
- Jie Wang
- Department of Microbiology and Immunology, University of Texas Health Science Center, San Antonio, TX 78229, USA
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43
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Chen D, Lei L, Lu C, Flores R, DeLisa MP, Roberts TC, Romesberg FE, Zhong G. Secretion of the chlamydial virulence factor CPAF requires the Sec-dependent pathway. MICROBIOLOGY-SGM 2010; 156:3031-3040. [PMID: 20522495 PMCID: PMC3068695 DOI: 10.1099/mic.0.040527-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The chlamydial protease/proteasome-like activity factor (CPAF) is secreted into the host cytosol to degrade various host factors that benefit chlamydial intracellular survival. Although the full-length CPAF is predicted to contain a putative signal peptide at its N terminus, the secretion pathway of CPAF is still unknown. Here, we have provided experimental evidence that the N-terminal sequence covering the M1–G31 region was cleaved from CPAF during chlamydial infection. The CPAF N-terminal sequence, when expressed in a phoA gene fusion construct, was able to direct the export of the mature PhoA protein across the inner membrane of wild-type Escherichia coli. However, E. coli mutants deficient in SecB failed to support the CPAF signal-peptide-directed secretion of PhoA. Since native PhoA secretion was known to be independent of SecB, this SecB dependence must be rendered by the CPAF leader peptide. Furthermore, lack of SecY function also blocked the CPAF signal-peptide-directed secretion of PhoA. Most importantly, CPAF secretion into the host cell cytosol during chlamydial infection was selectively inhibited by an inhibitor specifically targeting type I signal peptidase but not by a type III secretion-system-specific inhibitor. Together, these observations have demonstrated that the chlamydial virulence factor CPAF relies on Sec-dependent transport for crossing the chlamydial inner membrane, which has provided essential information for further delineating the pathways of CPAF action and understanding chlamydial pathogenic mechanisms.
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Affiliation(s)
- Ding Chen
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Lei Lei
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Chunxue Lu
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Rhonda Flores
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Matthew P DeLisa
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Tucker C Roberts
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Floyd E Romesberg
- Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Rd, La Jolla, CA 92037, USA
| | - 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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44
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Chen D, Lei L, Flores R, Huang Z, Wu Z, Chai J, Zhong G. Autoprocessing and self-activation of the secreted protease CPAF in Chlamydia-infected cells. Microb Pathog 2010; 49:164-73. [PMID: 20510344 DOI: 10.1016/j.micpath.2010.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 05/14/2010] [Accepted: 05/18/2010] [Indexed: 10/19/2022]
Abstract
The Chlamydia-secreted protease/proteasome-like activity factor (CPAF) is synthesized as a proenzyme (proCPAF) and requires processing for proteolytic activity. Recent structural studies have further demonstrated that CPAF is a serine protease that can undergo autoprocessing and self-activation in a concentration-dependent manner in vitro. However, it is not known how CPAF is processed and activated during chlamydial infection. In the current study, we used a mutant CPAF designated as CPAF(E558A) that is deficient in processing by itself as a substrate to search for putative CPAF activation factor(s) in Chlamydia-infected cells. CPAF(E558A) was processed by the lysates made from Chlamydia-infected cells and the processing activity correlated with the presence of endogenous active CPAF in the fractionated lysate samples. CPAF produced in the Chlamydia-infected cells is required for processing the mutant CPAF(E558A) since the processing activity was removed by depletion with anti-CPAF but not control antibodies. Furthermore, a purified and activated wild type CPAF alone was sufficient for processing CPAF(E558A) and no other chlamydial proteases are required. Finally, fusion tag-induced oligomerization can lead to autoprocessing and self-activation of the wild type CPAF in mammalian cells. These observations together have demonstrated that CPAF undergoes autoprocessing and self-activation during chlamydial infection.
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Affiliation(s)
- Ding Chen
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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45
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Localization and Characterization of Hypothetical Protein CT358 in The Chlamydia trachomatis-Infected Cells*. PROG BIOCHEM BIOPHYS 2009. [DOI: 10.3724/sp.j.1206.2008.00109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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46
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Zhong G. Killing me softly: chlamydial use of proteolysis for evading host defenses. Trends Microbiol 2009; 17:467-74. [PMID: 19765998 DOI: 10.1016/j.tim.2009.07.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 04/06/2009] [Accepted: 07/13/2009] [Indexed: 12/13/2022]
Abstract
Chlamydial infections in humans cause severe health problems, including blinding trachoma and sexually transmitted diseases. Although the involved pathogenic mechanisms remain unclear, the ability to replicate and maintain long-term residence in the infected cells seems to significantly contribute to chlamydial pathogenicity. These obligate intracellular parasites maintain a delicate balance between exploiting and protecting their host: they occupy intracellular space and acquire nutrients from the infected cells, but at the same time they have to maintain the integrity of the host cells for the completion of their intracellular growth. For this purpose, chlamydiae hijack certain signaling pathways that prevent the host cells from undergoing apoptosis induced by intracellular stress and protect the infected cells from recognition and attack by host defenses. Interestingly, one of the strategies that chlamydiae use for these purposes is the induction of limited proteolysis of host proteins, which is the main focus of this article.
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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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47
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Zhang X, Gao L, Lei L, Zhong Y, Dube P, Berton MT, Arulanandam B, Zhang J, Zhong G. A MyD88-dependent early IL-17 production protects mice against airway infection with the obligate intracellular pathogen Chlamydia muridarum. THE JOURNAL OF IMMUNOLOGY 2009; 183:1291-300. [PMID: 19542374 DOI: 10.4049/jimmunol.0803075] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We found that IL-17, a signature cytokine of Th17, was produced early in the innate immunity phase after an intranasal infection with the obligate intracellular pathogen Chlamydia muridarum. The airway IL-17, which peaked at 48 h after infection, was dependent on live chlamydial organism replication and MyD88-mediated signaling pathways. Treatment with antibiotics or knockout of the MyD88 gene, but not Toll/IL receptor domain-containing adapter-inducing IFN-beta, can block the early IL-17 production. Treatment of mice with an anti-IL-17-neutralizing mAb enhanced growth of chlamydial organisms in the lung, dissemination to other organs, and decreased mouse survival, whereas treatment with an isotype-matched control IgG had no effect. Although IL-17 did not directly affect chlamydial growth in cell culture, it enhanced the production of other inflammatory cytokines and chemokines by Chlamydia-infected cells and promoted neutrophil infiltration in mouse airways during chlamydial infection, which may contribute to the antichlamydial effect of IL-17. These observations suggest that an early IL-17 response as an innate immunity component plays an important role in initiating host defense against infection with intracellular bacterial pathogens in the airway.
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Affiliation(s)
- Xiaoyun Zhang
- Department of Microbiology and Immunology, University of Texas Health Science Center, San Antonio, TX 78229, USA
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48
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Sharma M, Rudel T. Apoptosis resistance in Chlamydia-infected cells: a fate worse than death? ACTA ACUST UNITED AC 2009; 55:154-61. [PMID: 19281566 DOI: 10.1111/j.1574-695x.2008.00515.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chlamydia has long been studied as an intracellular pathogen causing widespread diseases. In the last three decades, the field of apoptosis has rapidly emerged, and as a consequence, research on infectious diseases in general and on Chlamydia-host interaction in particular shifted to apoptosis modulation. Ten years ago, the first paper describing the drastic inhibition of apoptosis in Chlamydia-infected cells was published. In a reversal of roles, here was a pathogen that was strongly protecting cells in an organism against destruction by the organism's immune system. Since then, numerous studies have described apoptosis inhibition by Chlamydia and the mechanisms involved, but still there is a lack of general consensus on the subject. With a section of studies even reporting the induction of cell death by Chlamydia and not its inhibition, the field became even more diverse and complicated. In this review, an attempt is made to discuss the recent findings on apoptosis modulation by chlamydial species.
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Affiliation(s)
- Manu Sharma
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
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49
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Wang J, Chen L, Chen F, Zhang X, Zhang Y, Baseman J, Perdue S, Yeh IT, Shain R, Holland M, Bailey R, Mabey D, Yu P, Zhong G. A chlamydial type III-secreted effector protein (Tarp) is predominantly recognized by antibodies from humans infected with Chlamydia trachomatis and induces protective immunity against upper genital tract pathologies in mice. Vaccine 2009; 27:2967-80. [PMID: 19428908 DOI: 10.1016/j.vaccine.2009.02.095] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 02/20/2009] [Accepted: 02/24/2009] [Indexed: 01/07/2023]
Abstract
Chlamydia trachomatis genome is predicted to encode a type III secretion system consisting of more than 40 open reading frames (ORFs). To test whether these ORFs are expressed and immunogenic during chlamydial infection in humans, we expressed 55 chlamydial ORFs covering all putative type III secretion components plus control molecules as fusion proteins and measured the reactivity of these fusion proteins with antibodies from patients infected with C. trachomatis in the urogenital tract (24 antisera) or in the ocular tissue (8 antisera). Forty-five of the 55 proteins were recognized by at least 1 of the 32 human antisera, suggesting that these proteins are both expressed and immunogenic during chlamydial infection in humans. Tarp, a putative type III secretion effector protein, was identified as a novel immunodominant antigen due to its reactivity with the human antisera at high frequency and titer. The expression and immunogenicity of Tarp were confirmed in cell culture and mouse systems. Tarp was mainly associated with the infectious form of chlamydial organisms and became undetectable between 13 and 24 h during the infection cycle in cell culture. Mice intravaginally infected with C. muridarum developed Tarp-specific humoral and cellular immune responses. More importantly, immunization of mice with Tarp induced Th1-dominant immunity that significantly reduced the shedding of live organisms from the lower genital tract and attenuated inflammatory pathologies in the fallopian tube tissues. These observations have demonstrated that Tarp, an immunodominant antigen identified by human antisera, can induce protective immunity against chlamydial infection and pathology in mice.
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Affiliation(s)
- Jie Wang
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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50
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Ying S, Pettengill M, Latham ER, Walch A, Ojcius DM, Häcker G. Premature apoptosis of Chlamydia-infected cells disrupts chlamydial development. J Infect Dis 2009; 198:1536-44. [PMID: 18821848 DOI: 10.1086/592755] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The obligate intracellular development of Chlamydia suggests that the bacteria should be vulnerable to premature host cell apoptosis, but because Chlamydia-infected cells are apoptosis resistant, this has never been able to be tested. We have devised a system to circumvent the apoptotic block imposed by chlamydial infection. When the proapoptotic protein Bim(S) was experimentally induced, epithelial cells underwent apoptosis that was not blocked by chlamydial infection. Apoptosis during the developmental cycle prevented the generation of infectious bacteria and caused transcriptional changes of bacterial genes and loss of intracellular ATP. Intriguingly, although apoptosis resulted in destruction of host cell structures and of the Chlamydia inclusion, and prevented generation of elementary bodies, Bim(S) induction in the presence of a caspase inhibitor allowed differentiation into morphologically normal but noninfectious elementary bodies. These data show that chlamydial infection renders host cells apoptosis resistant at a premitochondrial step and demonstrate the consequences of premature apoptosis for development of the bacteria.
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Affiliation(s)
- Songmin Ying
- Institute for Medical Microbiology, Immunology and Hygiene, Technical University Munich, Germany
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