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Hoang-Phou S, Pal S, Slepenkin A, Abisoye-Ogunniyun A, Zhang Y, Gilmore SF, Shelby M, Bourguet F, Mohagheghi M, Noy A, Rasley A, de la Maza LM, Coleman MA. Evaluation in mice of cell-free produced CT584 as a Chlamydia vaccine antigen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.04.597210. [PMID: 38895407 PMCID: PMC11185655 DOI: 10.1101/2024.06.04.597210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Chlamydia trachomatis is the most prevalent bacterial sexually transmitted pathogen worldwide. Since chlamydial infection is largely asymptomatic with the potential for serious complications, a preventative vaccine is likely the most viable long-term answer to this public health threat. Cell-free protein synthesis (CFPS) utilizes the cellular protein manufacturing machinery decoupled from the requirement for maintaining cellular viability, offering the potential for flexible, rapid, and de-centralized production of recombinant protein vaccine antigens. Here, we use CFPS to produce the putative chlamydial type three secretion system (T3SS) needle-tip protein, CT584, for use as a vaccine antigen in mouse models. High-speed atomic force microscopy (HS-AFM) imaging and computer simulations confirm that CFPS-produced CT584 retains a native-like structure prior to immunization. Female mice were primed with CT584 adjuvanted with CpG-1826 intranasally (i.n.) or CpG-1826 + Montanide ISA 720 intramuscularly (i.m.), followed four-weeks later by an i.m. boost before respiratory challenge with 104 inclusion forming units (IFU) of Chlamydia muridarum. Immunization with CT584 generated robust antibody responses but weak cell mediated immunity and failed to protect against i.n. challenge as demonstrated by body weight loss, increased lungs' weights and the presence of high numbers of IFUs in the lungs. While CT584 alone may not be the ideal vaccine candidate, the speed and flexibility with which CFPS can be used to produce other potential chlamydial antigens makes it an attractive technique for antigen production.
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Affiliation(s)
- Steven Hoang-Phou
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Sukumar Pal
- Department of Pathology and Laboratory Medicine, University of California, Irvine, CA 92697, USA
| | - Anatoli Slepenkin
- Department of Pathology and Laboratory Medicine, University of California, Irvine, CA 92697, USA
| | - Abisola Abisoye-Ogunniyun
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Yuliang Zhang
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Sean F Gilmore
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Megan Shelby
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Feliza Bourguet
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Mariam Mohagheghi
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Aleksandr Noy
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Amy Rasley
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
| | - Luis M de la Maza
- Department of Pathology and Laboratory Medicine, University of California, Irvine, CA 92697, USA
| | - Matthew A Coleman
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
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Huang B, Zhu Z, Dai Y, Yan C, Xu J, Sun L, Zhang Q, An X, Lai F. Characterization of translocon proteins in the type III secretion system of Lawsonia intracellularis. Vet Res 2023; 54:108. [PMID: 37993950 PMCID: PMC10664548 DOI: 10.1186/s13567-023-01243-0] [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: 08/12/2023] [Accepted: 10/24/2023] [Indexed: 11/24/2023] Open
Abstract
Lawsonia intracellularis, the etiologic agent of proliferative enteropathy (PE), is an obligate intracellular Gram-negative bacterium possessing a type III secretion system (T3SS), which enables the pathogen to translocate effector proteins into targeted host cells to modulate their functions. T3SS is a syringe-like apparatus consisting of a base, an extracellular needle, a tip, and a translocon. The translocon proteins assembled by two hydrophobic membrane proteins can form pores in the host-cell membrane, and therefore play an essential role in the function of T3SS. To date, little is known about the T3SS and translocon proteins of L. intracellularis. In this study, we first analyzed the conservation of the T3S apparatus between L. intracellularis and Yersinia, and characterized the putative T3S hydrophobic major translocon protein LI1158 and minor translocon protein LI1159 in the L. intracellularis genome. Then, by using Yersinia pseudotuberculosis as a surrogate system, we found that the full-length LI1158 and LI1159 proteins, but not the putative class II chaperone LI1157, were secreted in a - Ca2+ and T3SS-dependent manner and the secretion signal was located at the N terminus (aa 1-40). Furthermore, yeast-two hybrid experiments revealed that LI1158 and LI1159 could self-interact, and LI1159 could interact with LI1157. However, unlike CPn0809 and YopB, which are the major hydrophobic translocon proteins of the T3SS of C. pneumoniae and Yersinia, respectively, full-length LI1158 was non-toxic to both yeast and Escherichia coli cells, but full-length LI1159 showed certain toxicity to E. coli cells. Taken together, despite some differences from the findings in other bacteria, our results demonstrate that LI1158 and LI1159 may be the translocon proteins of L. intracellularis T3SS, and probably play important roles in the translocation of effector proteins at the early pathogen infection stage.
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Affiliation(s)
- Beibei Huang
- School of Bioscience and Bioengineering, Nanchang Key Laboratory of Fermentation Application Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Zihe Zhu
- School of Bioscience and Bioengineering, Nanchang Key Laboratory of Fermentation Application Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Yimin Dai
- School of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Chengxian Yan
- School of Bioscience and Bioengineering, Nanchang Key Laboratory of Fermentation Application Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Jingyu Xu
- School of Bioscience and Bioengineering, Nanchang Key Laboratory of Fermentation Application Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Lingling Sun
- School of Bioscience and Bioengineering, Nanchang Key Laboratory of Fermentation Application Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Qinghua Zhang
- School of Bioscience and Bioengineering, Nanchang Key Laboratory of Fermentation Application Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Xuejiao An
- School of Bioscience and Bioengineering, Nanchang Key Laboratory of Fermentation Application Technology, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Fenju Lai
- Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Nanchang, Jiangxi, China.
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Hakiem OR, Rizvi SMA, Ramirez C, Tan M. Euo is a developmental regulator that represses late genes and activates midcycle genes in Chlamydia trachomatis. mBio 2023; 14:e0046523. [PMID: 37565751 PMCID: PMC10653925 DOI: 10.1128/mbio.00465-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/22/2023] [Indexed: 08/12/2023] Open
Abstract
IMPORTANCE In this study, we developed a correlative approach that combined DNA immunoprecipitation-seq and RNA-seq analyses to define the regulon of the Chlamydia trachomatis transcription factor Euo. We confirmed the proposed role of Euo as a transcriptional repressor of late chlamydial genes but also showed that Euo activates transcription of a subset of midcycle genes and autoregulates its own expression via negative feedback. This study validates and expands the role of Euo as an important developmental regulator in C. trachomatis. In addition, this genome-wide correlative approach can be applied to study transcription factors in other pathogenic bacteria.
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Affiliation(s)
- Owais R. Hakiem
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
| | - Syed M. A. Rizvi
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
| | - Cuper Ramirez
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, California, USA
| | - Ming Tan
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
- Department of Medicine, University of California Irvine, Irvine, California, USA
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Abstract
Type III secretion systems (T3SSs) are utilized by Gram-negative pathogens to enhance their pathogenesis. This secretion system is associated with the delivery of effectors through a needle-like structure from the bacterial cytosol directly into a target eukaryotic cell. These effector proteins then manipulate specific eukaryotic cell functions to benefit pathogen survival within the host. The obligate intracellular pathogens of the family Chlamydiaceae have a highly evolutionarily conserved nonflagellar T3SS that is an absolute requirement for their survival and propagation within the host with about one-seventh of the genome dedicated to genes associated with the T3SS apparatus, chaperones, and effectors. Chlamydiae also have a unique biphasic developmental cycle where the organism alternates between an infectious elementary body (EB) and replicative reticulate body (RB). T3SS structures have been visualized on both EBs and RBs. And there are effector proteins that function at each stage of the chlamydial developmental cycle, including entry and egress. This review will discuss the history of the discovery of chlamydial T3SS and the biochemical characterization of components of the T3SS apparatus and associated chaperones in the absence of chlamydial genetic tools. These data will be contextualized into how the T3SS apparatus functions throughout the chlamydial developmental cycle and the utility of heterologous/surrogate models to study chlamydial T3SS. Finally, there will be a targeted discussion on the history of chlamydial effectors and recent advances in the field.
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Affiliation(s)
- Elizabeth A. Rucks
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Durham Research Center II, Omaha, Nebraska, USA
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Collingro A, Köstlbacher S, Siegl A, Toenshoff ER, Schulz F, Mitchell SO, Weinmaier T, Rattei T, Colquhoun DJ, Horn M. The Fish Pathogen "Candidatus Clavichlamydia salmonicola"-A Missing Link in the Evolution of Chlamydial Pathogens of Humans. Genome Biol Evol 2023; 15:evad147. [PMID: 37615694 PMCID: PMC10448858 DOI: 10.1093/gbe/evad147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2023] [Indexed: 08/25/2023] Open
Abstract
Chlamydiae like Chlamydia trachomatis and Chlamydia psittaci are well-known human and animal pathogens. Yet, the chlamydiae are a much larger group of evolutionary ancient obligate intracellular bacteria that includes predominantly symbionts of protists and diverse animals. This makes them ideal model organisms to study evolutionary transitions from symbionts in microbial eukaryotes to pathogens of humans. To this end, comparative genome analysis has served as an important tool. Genome sequence data for many chlamydial lineages are, however, still lacking, hampering our understanding of their evolutionary history. Here, we determined the first high-quality draft genome sequence of the fish pathogen "Candidatus Clavichlamydia salmonicola", representing a separate genus within the human and animal pathogenic Chlamydiaceae. The "Ca. Clavichlamydia salmonicola" genome harbors genes that so far have been exclusively found in Chlamydia species suggesting that basic mechanisms important for the interaction with chordate hosts have evolved stepwise in the history of chlamydiae. Thus, the genome sequence of "Ca. Clavichlamydia salmonicola" allows to constrain candidate genes to further understand the evolution of chlamydial virulence mechanisms required to infect mammals.
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Affiliation(s)
- Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Stephan Köstlbacher
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Doctoral School in Microbiology and Environmental Science, University of Vienna, Vienna, Austria
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Alexander Siegl
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Elena R Toenshoff
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich (ETH), Zürich, Switzerland
| | - Frederik Schulz
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- DOE Joint Genome Institute, Berkeley, California, USA
| | | | - Thomas Weinmaier
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Thomas Rattei
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | | | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
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6
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Huang W, Hu S, Zhu Y, Liu S, Zhou X, Fang Y, Lu Y, Wang R. Metagenomic surveillance and comparative genomic analysis of Chlamydia psittaci in patients with pneumonia. Front Microbiol 2023; 14:1157888. [PMID: 37323913 PMCID: PMC10265514 DOI: 10.3389/fmicb.2023.1157888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 05/12/2023] [Indexed: 06/17/2023] Open
Abstract
Chlamydia psittaci, a strictly intracellular bacterium, is an underestimated etiologic agent leading to infections in a broad range of animals and mild illness or pneumonia in humans. In this study, the metagenomes of bronchoalveolar lavage fluids from the patients with pneumonia were sequenced and highly abundant C. psittaci was found. The target-enriched metagenomic reads were recruited to reconstruct draft genomes with more than 99% completeness. Two C. psittaci strains from novel sequence types were detected and these were closely related to the animal-borne isolates derived from the lineages of ST43 and ST28, indicating the zoonotic transmissions of C. psittaci would benefit its prevalence worldwide. Comparative genomic analysis combined with public isolate genomes revealed that the pan-genome of C. psittaci possessed a more stable gene repertoire than those of other extracellular bacteria, with ~90% of the genes per genome being conserved core genes. Furthermore, the evidence for significantly positive selection was identified in 20 virulence-associated gene products, particularly bacterial membrane-embedded proteins and type three secretion machines, which may play important roles in the pathogen-host interactions. This survey uncovered novel strains of C. psittaci causing pneumonia and the evolutionary analysis characterized prominent gene candidates involved in bacterial adaptation to immune pressures. The metagenomic approach is of significance to the surveillance of difficult-to-culture intracellular pathogens and the research into molecular epidemiology and evolutionary biology of C. psittaci.
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Affiliation(s)
- Weifeng Huang
- Department of Intensive Care Medicine, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shuqin Hu
- Department of Critical Care Medicine, Shanghai General Hospital of Nanjing Medical University, Shanghai, China
| | - Yongzhe Zhu
- Department of Microbiology, Navy Medical University, Shanghai, China
| | - Shijia Liu
- Department of Pulmonary Disease, PLA 905 Hospital, Shanghai, China
| | - Xingya Zhou
- Genoxor Medical Science and Technology Inc., Shanghai, China
| | - Yuan Fang
- Genoxor Medical Science and Technology Inc., Shanghai, China
| | - Yihan Lu
- Department of Epidemiology, Ministry of Education Key Laboratory of Public Health Safety, School of Public Health, Fudan University, Shanghai, China
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai, China
| | - Ruilan Wang
- Department of Critical Care Medicine, Shanghai General Hospital of Nanjing Medical University, Shanghai, China
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7
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Virulence Factors in Colorectal Cancer Metagenomes and Association of Microbial Siderophores with Advanced Stages. Microorganisms 2022; 10:microorganisms10122365. [PMID: 36557618 PMCID: PMC9781273 DOI: 10.3390/microorganisms10122365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/26/2022] [Accepted: 10/26/2022] [Indexed: 12/05/2022] Open
Abstract
Colorectal cancer (CRC) is a growing public health challenge, featuring a multifactorial etiology and complex host-environment interactions. Recently, increasing evidence has pointed to the role of the gut microbiota in CRC development and progression. To explore the role of gut microbes in CRC, we retrieved metagenomic data from 156 stools from the European Nucleotide Archive database and mapped them against the VFDB database for virulence factors (VFs). GO annotations of VFs and KEGG pathways were then performed to predict the microbial functions and define functional pathways enriched in the tumor-associated microbiota. Interestingly, 306 VFs were detected in the metagenomic data. We revealed the enrichment of adenomas with VFs involved in cell adhesion, whereas in the early stages of CRC they were enriched in both adhesins and isochorismatase. Advanced stages of CRC were enriched with microbial siderophores, especially enterobactin, which was significantly associated with isochorismate synthase. We highlighted higher abundances of porins and transporters involved in antibiotic resistance and the development of biofilm in advanced stages of CRC. Most VFs detected in CRC, particularly in advanced stages, were shown to be included in siderophore biosynthesis pathways. This enrichment of predicted VFs supports the key role of the gut microbiota in the disease.
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8
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Gitsels A, Sanders N, Vanrompay D. Chlamydial Infection From Outside to Inside. Front Microbiol 2019; 10:2329. [PMID: 31649655 PMCID: PMC6795091 DOI: 10.3389/fmicb.2019.02329] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 09/24/2019] [Indexed: 12/16/2022] Open
Abstract
Chlamydia are obligate intracellular bacteria, characterized by a unique biphasic developmental cycle. Specific interactions with the host cell are crucial for the bacteria’s survival and amplification because of the reduced chlamydial genome. At the start of infection, pathogen-host interactions are set in place in order for Chlamydia to enter the host cell and reach the nutrient-rich peri-Golgi region. Once intracellular localization is established, interactions with organelles and pathways of the host cell enable the necessary hijacking of host-derived nutrients. Detailed information on the aforementioned processes will increase our understanding on the intracellular pathogenesis of chlamydiae and hence might lead to new strategies to battle chlamydial infection. This review summarizes how chlamydiae generate their intracellular niche in the host cell, acquire host-derived nutrients in order to enable their growth and finally exit the host cell in order to infect new cells. Moreover, the evolution in the development of molecular genetic tools, necessary for studying the chlamydial infection biology in more depth, is discussed in great detail.
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Affiliation(s)
- Arlieke Gitsels
- Laboratory for Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Niek Sanders
- Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Daisy Vanrompay
- Laboratory for Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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9
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Bulir DC, Liang S, Lee A, Chong S, Simms E, Stone C, Kaushic C, Ashkar A, Mahony JB. Immunization with chlamydial type III secretion antigens reduces vaginal shedding and prevents fallopian tube pathology following live C. muridarum challenge. Vaccine 2016; 34:3979-85. [PMID: 27325352 DOI: 10.1016/j.vaccine.2016.06.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/25/2016] [Accepted: 06/14/2016] [Indexed: 11/26/2022]
Abstract
Chlamydia trachomatis infections in women are often asymptomatic and if left untreated can lead to significant late sequelae including pelvic inflammatory disease and tubal factor infertility. Vaccine development efforts over the past three decades have been unproductive and there is no vaccine approved for use in humans. The existence of serologically distinct strains or serovars of C. trachomatis mandates a vaccine that will provide protection against multiple serovars. Chlamydia spp. use a highly conserved type III secretion system (T3SS) composed of both structural and effector proteins which is an essential virulence factor for infection and intracellular replication. In this study we evaluated a novel fusion protein antigen (BD584) which consists of three T3SS proteins from C. trachomatis (CopB, CopD, and CT584) as a potential chlamydial vaccine candidate. Intranasal immunization with BD584 elicited serum neutralizing antibodies that inhibited C. trachomatis infection in vitro. Following intravaginal challenge with C. muridarum, immunized mice had a 95% reduction in chlamydial shedding from the vagina at the peak of infection and cleared the infection sooner than control mice. Immunization with BD584 also reduced the rate of hydrosalpinx by 87.5% compared to control mice. Together, these results suggest that highly conserved proteins of the chlamydial T3SS may represent good candidates for a Chlamydia vaccine.
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Affiliation(s)
- David C Bulir
- M. G. DeGroote Institute for Infectious Disease Research, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Steven Liang
- M. G. DeGroote Institute for Infectious Disease Research, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Amanda Lee
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Sylvia Chong
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Elizabeth Simms
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Christopher Stone
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Charu Kaushic
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada
| | - Ali Ashkar
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada
| | - James B Mahony
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada.
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10
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Engel AC, Herbst F, Kerres A, Galle JN, Hegemann JH. The Type III Secretion System-Related CPn0809 from Chlamydia pneumoniae. PLoS One 2016; 11:e0148509. [PMID: 26895250 PMCID: PMC4760673 DOI: 10.1371/journal.pone.0148509] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 01/20/2016] [Indexed: 11/19/2022] Open
Abstract
Chlamydia pneumoniae is an intracellular Gram-negative bacterium that possesses a type III secretion system (T3SS), which enables the pathogen to deliver, in a single step, effector proteins for modulation of host-cell functions into the human host cell cytosol to establish a unique intracellular niche for replication. The translocon proteins located at the top of the T3SS needle filament are essential for its function, as they form pores in the host-cell membrane. Interestingly, unlike other Gram-negative bacteria, C. pneumoniae has two putative translocon operons, named LcrH_1 and LcrH_2. However, little is known about chlamydial translocon proteins. In this study, we analyzed CPn0809, one of the putative hydrophobic translocators encoded by the LcrH_1 operon, and identified an 'SseC-like family' domain characteristic of T3S translocators. Using bright-field and confocal microscopy, we found that CPn0809 is associated with EBs during early and very late phases of a C. pneumoniae infection. Furthermore, CPn0809 forms oligomers, and interacts with the T3SS chaperone LcrH_1, via its N-terminal segment. Moreover, expression of full-length CPn0809 in the heterologous host Escherichia coli causes a grave cytotoxic effect that leads to cell death. Taken together, our data indicate that CPn0809 likely represents one of the translocon proteins of the C. pneumoniae T3SS, and possibly plays a role in the translocation of effector proteins in the early stages of infection.
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Affiliation(s)
- Astrid C. Engel
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Frauke Herbst
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Anne Kerres
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Jan N. Galle
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Johannes H. Hegemann
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität, Düsseldorf, Germany
- * E-mail:
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11
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Ferrell JC, Fields KA. A working model for the type III secretion mechanism in Chlamydia. Microbes Infect 2015; 18:84-92. [PMID: 26515030 DOI: 10.1016/j.micinf.2015.10.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 10/19/2015] [Accepted: 10/19/2015] [Indexed: 01/09/2023]
Abstract
It has been appreciated for almost 20 years that members of the Chlamydiales possess a virulence-associated type III secretion mechanism. Given the obligate intracellular nature of these bacteria, defining exactly how type III secretion functions to promote pathogenesis has been challenging. We present a working model herein that is based on current evidence.
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Affiliation(s)
- Joshua C Ferrell
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Kenneth A Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
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12
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Bulir DC, Waltho DA, Stone CB, Liang S, Chiang CKW, Mwawasi KA, Nelson JC, Zhang SW, Mihalco SP, Scinocca ZC, Mahony JB. Chlamydia Outer Protein (Cop) B from Chlamydia pneumoniae possesses characteristic features of a type III secretion (T3S) translocator protein. BMC Microbiol 2015; 15:163. [PMID: 26272448 PMCID: PMC4536800 DOI: 10.1186/s12866-015-0498-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 08/03/2015] [Indexed: 01/26/2023] Open
Abstract
Background Chlamydia spp. are believed to use a conserved virulence factor called type III secretion (T3S) to facilitate the delivery of effector proteins from the bacterial pathogen to the host cell. Important early effector proteins of the type III secretion system (T3SS) are a class of proteins called the translocators. The translocator proteins insert into the host cell membrane to form a pore, allowing the injectisome to dock onto the host cell to facilitate translocation of effectors. CopB is a predicted hydrophobic translocator protein within the chlamydial T3SS. Results In this study, we identified a novel interaction between the hydrophobic translocator, CopB, and the putative filament protein, CdsF. Furthermore, we identified a conserved PxLxxP motif in CopB (amino acid residues 166–171), which is required for interaction with its cognate chaperone, LcrH_1. Using a synthetic peptide derived from the chaperone binding motif of CopB, we were able to block the LcrH_1 interaction with either CopB or CopD; this CopB peptide was capable of inhibiting C. pneumoniae infection of HeLa cells at micromolar concentrations. An antibody raised against the N-terminus of CopB was able to inhibit C. pneumoniae infection of HeLa cells. Conclusion The inhibition of the LcrH_1:CopB interaction with a cognate peptide and subsequent inhibition of host cell infection provides strong evidence that T3S is an essential virulence factor for chlamydial infection and pathogenesis. Together, these results support that CopB plays the role of a hydrophobic translocator.
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Affiliation(s)
- David C Bulir
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Daniel A Waltho
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Christopher B Stone
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Steven Liang
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Christopher K W Chiang
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Kenneth A Mwawasi
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Jordan C Nelson
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Steven W Zhang
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Samantha P Mihalco
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Zachariah C Scinocca
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - James B Mahony
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada. .,Regional Virology Laboratory, St. Joseph's Healthcare, 50 Charlton Ave. E, Hamilton, ON, L8N 4A6, Canada.
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