1
|
Hatch ND, Ouellette SP. Identification of the alternative sigma factor regulons of Chlamydia trachomatis using multiplexed CRISPR interference. mSphere 2023; 8:e0039123. [PMID: 37747235 PMCID: PMC10597470 DOI: 10.1128/msphere.00391-23] [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: 07/13/2023] [Accepted: 08/07/2023] [Indexed: 09/26/2023] Open
Abstract
Chlamydia trachomatis is a developmentally regulated, obligate intracellular bacterium that encodes three sigma factors: σ66, σ54, and σ28. σ66 is the major sigma factor controlling most transcription initiation during early- and mid-cycle development as the infectious elementary body (EB) transitions to the non-infectious reticulate body (RB) that replicates within an inclusion inside the cell. The roles of the minor sigma factors, σ54 and σ28, have not been well characterized to date; however, there are data to suggest each functions in late-stage development and secondary differentiation as RBs transition to EBs. As the process of secondary differentiation itself is poorly characterized, clarifying the function of these alternative sigma factors by identifying the genes regulated by them will further our understanding of chlamydial differentiation. We hypothesize that σ54 and σ28 have non-redundant and essential functions for initiating late gene transcription thus mediating secondary differentiation in Chlamydia. Here, we demonstrate the necessity of each minor sigma factor in successfully completing the developmental cycle. We have implemented and validated multiplexed Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) interference techniques, novel to the chlamydial field to examine the effects of knocking down each alternative sigma factor individually and simultaneously. In parallel, we also overexpressed each sigma factor. Altering transcript levels for either or both alternative sigma factors resulted in a severe defect in EB production as compared to controls. Furthermore, RNA sequencing identified differentially expressed genes during alternative sigma factor dysregulation, indicating the putative regulons of each. These data demonstrate that the levels of alternative sigma factors must be carefully regulated to facilitate chlamydial growth and differentiation. IMPORTANCE Chlamydia trachomatis is a significant human pathogen in both developed and developing nations. Due to the organism's unique developmental cycle and intracellular niche, basic research has been slow and arduous. However, recent advances in chlamydial genetics have allowed the field to make significant progress in experimentally interrogating the basic physiology of Chlamydia. Broadly speaking, the driving factors of chlamydial development are poorly understood, particularly regarding how the later stages of development are regulated. Here, we employ a novel genetic tool for use in Chlamydia while investigating the effects of dysregulating the two alternative sigma factors in the organism that help control transcription initiation. We provide further evidence for both sigma factors' essential roles in late-stage development and their potential regulons, laying the foundation for deeper experimentation to uncover the molecular pathways involved in chlamydial differentiation.
Collapse
Affiliation(s)
- Nathan D. Hatch
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Scot P. Ouellette
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| |
Collapse
|
2
|
Dembek ZF, Mothershead JL, Owens AN, Chekol T, Wu A. Psittacosis: An Underappreciated and Often Undiagnosed Disease. Pathogens 2023; 12:1165. [PMID: 37764973 PMCID: PMC10536718 DOI: 10.3390/pathogens12091165] [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: 08/10/2023] [Revised: 09/02/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
The bacterial agent Chlamydia psittaci, and the resulting disease of psittacosis, is a little-known and underappreciated infectious disease by healthcare practitioners and in public health in general. C. psittaci infections can cause significant psittacosis outbreaks, with person-to-person transmission documented in the last decade. In this publication, we review the pathogen and its disease, as well as examine the potential for genetic manipulation in this organism to create a more deadly pathogen. Recent disease surveys indicate that currently, the highest incidences of human disease exist in Australia, Germany and the UK. We recommend the universal public health reporting of C. psittaci and psittacosis disease and increasing the promotion of public health awareness.
Collapse
Affiliation(s)
- Zygmunt F. Dembek
- Battelle Memorial Institute, Support to DTRA Technical Reachback, Columbus, OH 43201, USA; (Z.F.D.); (T.C.)
| | - Jerry L. Mothershead
- Applied Research Associates (ARA), Support to DTRA Technical Reachback, Albuquerque, NM 87110, USA;
| | - Akeisha N. Owens
- Defense Threat Reduction Agency (DTRA), Fort Belvoir, VA 22060, USA;
| | - Tesema Chekol
- Battelle Memorial Institute, Support to DTRA Technical Reachback, Columbus, OH 43201, USA; (Z.F.D.); (T.C.)
| | - Aiguo Wu
- Defense Threat Reduction Agency (DTRA), Fort Belvoir, VA 22060, USA;
| |
Collapse
|
3
|
Fisher DJ, Beare PA. Recent advances in genetic systems in obligate intracellular human-pathogenic bacteria. Front Cell Infect Microbiol 2023; 13:1202245. [PMID: 37404720 PMCID: PMC10315504 DOI: 10.3389/fcimb.2023.1202245] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/22/2023] [Indexed: 07/06/2023] Open
Abstract
The ability to genetically manipulate a pathogen is fundamental to discovering factors governing host-pathogen interactions at the molecular level and is critical for devising treatment and prevention strategies. While the genetic "toolbox" for many important bacterial pathogens is extensive, approaches for modifying obligate intracellular bacterial pathogens were classically limited due in part to the uniqueness of their obligatory lifestyles. Many researchers have confronted these challenges over the past two and a half decades leading to the development of multiple approaches to construct plasmid-bearing recombinant strains and chromosomal gene inactivation and deletion mutants, along with gene-silencing methods enabling the study of essential genes. This review will highlight seminal genetic achievements and recent developments (past 5 years) for Anaplasma spp., Rickettsia spp., Chlamydia spp., and Coxiella burnetii including progress being made for the still intractable Orientia tsutsugamushi. Alongside commentary of the strengths and weaknesses of the various approaches, future research directions will be discussed to include methods for C. burnetii that should have utility in the other obligate intracellular bacteria. Collectively, the future appears bright for unraveling the molecular pathogenic mechanisms of these significant pathogens.
Collapse
Affiliation(s)
- Derek J. Fisher
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, United States
| | - Paul A. Beare
- Rocky Mountain Laboratory, National Institute of Health, Hamilton, MT, United States
| |
Collapse
|
4
|
Hatch ND, Ouellette SP. Identification of the alternative sigma factor regulons of Chlamydia trachomatis using multiplexed CRISPR interference. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.27.538638. [PMID: 37162869 PMCID: PMC10168357 DOI: 10.1101/2023.04.27.538638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
C. trachomatis is a developmentally regulated, obligate intracellular bacterium that encodes three sigma factors: σ66, σ54, and σ28. σ66 is the major sigma factor controlling most transcription initiation during early and mid-cycle development as the infectious EB transitions to the non-infectious RB that replicates within an inclusion inside the cell. The roles of the minor sigma factors, σ54 and σ28, have not been well characterized to date - however, there are data to suggest each functions in late-stage development and secondary differentiation as RBs transition to EBs. As the process of secondary differentiation itself is poorly characterized, clarifying the function of these alternative sigma factors by identifying the genes regulated by them will further our understanding of chlamydial differentiation. We hypothesize that σ54 and σ28 have non-redundant and essential functions for initiating late gene transcription thus mediating secondary differentiation in Chlamydia . Here, we demonstrate the necessity of each minor sigma factor in successfully completing the developmental cycle. We have implemented and validated multiplexed CRISPRi techniques novel to the chlamydial field to examine effects of knocking down each alternative sigma factor individually and simultaneously. In parallel, we also overexpressed each sigma factor. Altering transcript levels for either or both alternative sigma factors resulted in a severe defect in EB production as compared to controls. Furthermore, RNA sequencing identified differentially expressed genes during alternative sigma factor dysregulation, indicating the putative regulons of each. These data demonstrate the levels of alternative sigma factors must be carefully regulated to facilitate chlamydial growth and differentiation. Importance Chlamydia trachomatis is a significant human pathogen in both developed and developing nations. Due to the organism's unique developmental cycle and intracellular niche, basic research has been slow and arduous. However, recent advances in chlamydial genetics have allowed the field to make significant progress in experimentally interrogating the basic physiology of Chlamydia . Broadly speaking, the driving factors of chlamydial development are poorly understood, particularly regarding how the later stages of development are regulated. Here, we employ a novel genetic tool for use in Chlamydia while investigating the effects of dysregulating the two alternative sigma factors in the organism that help control transcription initiation. We provide further evidence for both sigma factors' essential roles in late-stage development and their potential regulons, laying the foundation for deeper experimentation to uncover the molecular pathways involved in chlamydial differentiation.
Collapse
|
5
|
Fields KA, Bodero MD, Scanlon KR, Jewett TJ, Wolf K. A Minimal Replicon Enables Efficacious, Species-Specific Gene Deletion in Chlamydia and Extension of Gene Knockout Studies to the Animal Model of Infection Using Chlamydia muridarum. Infect Immun 2022; 90:e0045322. [PMID: 36350146 PMCID: PMC9753632 DOI: 10.1128/iai.00453-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/04/2022] [Indexed: 11/11/2022] Open
Abstract
The genus Chlamydia consists of diverse, obligate intracellular bacteria that infect various animals, including humans. Although chlamydial species share many aspects of the typical intracellular lifestyle, such as the biphasic developmental cycle and the preference for invasion of epithelial cells, each chlamydial strain also employs sophisticated species-specific strategies that contribute to an extraordinary diversity in organ and/or tissue tropism and disease manifestation. In order to discover and understand the mechanisms underlying how these pathogens infect particular hosts and cause specific diseases, it is imperative to develop a mutagenesis approach that would be applicable to every chlamydial species. We present functional evidence that the region between Chlamydia trachomatis and Chlamydia muridarum pgp6 and pgp7, containing four 22-bp tandem repeats that are present in all chlamydial endogenous plasmids, represents the plasmid origin of replication. Furthermore, by introducing species-specific ori regions into an engineered 5.45-kb pUC19-based plasmid, we generated vectors that can be successfully transformed into and propagated under selective pressure by C. trachomatis serovars L2 and D, as well as C. muridarum. Conversely, these vectors were rapidly lost upon removal of the selective antibiotic. This conditionally replicating system was used to generate a tarP deletion mutant by fluorescence-reported allelic exchange mutagenesis in both C. trachomatis serovar D and C. muridarum. The strains were analyzed using in vitro invasion and fitness assays. The virulence of the C. muridarum strains was then assessed in a murine infection model. Our approach represents a novel and efficient strategy for targeted genetic manipulation in Chlamydia beyond C. trachomatis L2. This advance will support comparative studies of species-specific infection biology and enable studies in a well-established murine model of chlamydial pathogenesis.
Collapse
Affiliation(s)
- Kenneth A. Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Maria D. Bodero
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Kaylyn R. Scanlon
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Travis J. Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Katerina Wolf
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| |
Collapse
|
6
|
Ölander M, Sixt BS. Bringing genetics to heretofore intractable obligate intracellular bacterial pathogens: Chlamydia and beyond. PLoS Pathog 2022; 18:e1010669. [PMID: 35901011 PMCID: PMC9333220 DOI: 10.1371/journal.ppat.1010669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Magnus Ölander
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Barbara S. Sixt
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
- * E-mail:
| |
Collapse
|
7
|
Banerjee A, Nelson DE. The growing repertoire of genetic tools for dissecting chlamydial pathogenesis. Pathog Dis 2021; 79:ftab025. [PMID: 33930127 PMCID: PMC8112481 DOI: 10.1093/femspd/ftab025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/28/2021] [Indexed: 01/29/2023] Open
Abstract
Multiple species of obligate intracellular bacteria in the genus Chlamydia are important veterinary and/or human pathogens. These pathogens all share similar biphasic developmental cycles and transition between intracellular vegetative reticulate bodies and infectious elementary forms, but vary substantially in their host preferences and pathogenic potential. A lack of tools for genetic engineering of these organisms has long been an impediment to the study of their biology and pathogenesis. However, the refinement of approaches developed in C. trachomatis over the last 10 years, and adaptation of some of these approaches to other Chlamydia spp. in just the last few years, has opened exciting new possibilities for studying this ubiquitous group of important pathogens.
Collapse
Affiliation(s)
- Arkaprabha Banerjee
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - David E Nelson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| |
Collapse
|
8
|
Shima K, Weber MM, Schnee C, Sachse K, Käding N, Klinger M, Rupp J. Development of a Plasmid Shuttle Vector System for Genetic Manipulation of Chlamydia psittaci. mSphere 2020; 5:e00787-20. [PMID: 32848009 PMCID: PMC7449628 DOI: 10.1128/msphere.00787-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/07/2020] [Indexed: 12/20/2022] Open
Abstract
The obligate intracellular bacterium Chlamydia psittaci is a known avian pathogen causing psittacosis in birds and is capable of zoonotic transmission. In human pulmonary infections, C. psittaci can cause pneumonia associated with significant mortality if inadequately diagnosed and treated. Although intracellular C. psittaci manipulates host cell organelles for its replication and survival, it has been difficult to demonstrate host-pathogen interactions in C. psittaci infection due to the lack of easy-to-handle genetic manipulation tools. Here, we show the genetic transformation of C. psittaci using a plasmid shuttle vector that contains a controllable gene induction system. The 7,553-bp plasmid p01DC12 was prepared from the nonavian C. psittaci strain 01DC12. We constructed the shuttle vector pCps-Tet-mCherry using the full sequence of p01DC12 and the 4,449-bp fragment of Chlamydia trachomatis shuttle vector pBOMB4-Tet-mCherry. pCps-Tet-mCherry includes genes encoding the green fluorescent protein (GFP), mCherry, and ampicillin resistance (AmpR). Target genes can be inserted at a multiple cloning site (MCS). Importantly, these genes can be regulated by a tetracycline-inducible (tet) promoter. Using the pCps-Tet-mCherry plasmid shuttle vector, we show the expression of GFP, as well as the induction of mCherry expression, in C. psittaci strain 02DC15, which belongs to the avian C. psittaci 6BC clade. Furthermore, we demonstrated that pCps-Tet-mCherry was stably retained in C. psittaci transformants. Thus, our C. psittaci plasmid shuttle vector system represents a novel targeted approach that enables the elucidation of host-pathogen interactions.IMPORTANCE Psittacosis, caused by avian C. psittaci, has a major economic impact in the poultry industry worldwide and represents a significant risk for zoonotic transmission to humans. In the past decade, the tools of genetic manipulation have been improved for chlamydial molecular studies. While several genetic tools have been mainly developed in Chlamydia trachomatis, a stable gene-inducible shuttle vector system has not to date been available for C. psittaci In this study, we adapted a C. trachomatis plasmid shuttle vector system to C. psittaci We constructed a C. psittaci plasmid backbone shuttle vector called pCps-Tet-mCherry. The construct expresses GFP in C. psittaci Importantly, exogeneous genes can be inserted at an MCS and are regulated by a tet promoter. The application of the pCps-Tet-mCherry shuttle vector system enables a promising new approach to investigate unknown gene functions of this pathogen.
Collapse
Affiliation(s)
- Kensuke Shima
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Mary M Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Christiane Schnee
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-lnstitut (Federal Research Institute for Animal Health), Jena, Germany
| | - Konrad Sachse
- RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Nadja Käding
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | | | - Jan Rupp
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel, Germany
| |
Collapse
|
9
|
The Cryptic Plasmid Improves Chlamydia Fitness in Different Regions of the Gastrointestinal Tract. Infect Immun 2020; 88:IAI.00860-19. [PMID: 31871102 DOI: 10.1128/iai.00860-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 12/20/2019] [Indexed: 12/19/2022] Open
Abstract
The cryptic plasmid is important for chlamydial colonization in the gastrointestinal tract. We used a combination of intragastric, intrajejunal, and intracolon inoculations to reveal the impact of the plasmid on chlamydial colonization in distinct regions of gastrointestinal tract. Following an intragastric inoculation, the plasmid significantly improved chlamydial colonization. At the tissue level, plasmid-positive Chlamydia produced infectious progenies throughout gastrointestinal tract. However, to our surprise, plasmid-deficient Chlamydia failed to produce infectious progenies in small intestine, although infectious progenies were eventually detected in large intestine, indicating a critical role of the plasmid in chlamydial differentiation into infectious particles in small intestine. The noninfectious status may represent persistent infection, since Chlamydia genomes proliferated in the same tissues. Following an intrajejunal inoculation that bypasses the gastric barrier, plasmid-deficient Chlamydia produced infectious progenies in small intestine but was 530-fold less infectious than plasmid-positive Chlamydia, suggesting that (i) the noninfectious status developed after intragastric inoculation might be induced by a combination of gastric and intestinal effectors and (ii) chlamydial colonization in small intestine was highly dependent on plasmid. Finally, following an intracolon inoculation, the dependence of chlamydial colonization on plasmid increased over time. Thus, we have demonstrated that the plasmid may be able to improve chlamydial fitness in different gut regions via different mechanisms, which has laid a foundation to further reveal the specific mechanisms.
Collapse
|
10
|
Cortina ME, Ende RJ, Bishop RC, Bayne C, Derré I. Chlamydia trachomatis and Chlamydia muridarum spectinomycin resistant vectors and a transcriptional fluorescent reporter to monitor conversion from replicative to infectious bacteria. PLoS One 2019; 14:e0217753. [PMID: 31170215 PMCID: PMC6553856 DOI: 10.1371/journal.pone.0217753] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/17/2019] [Indexed: 12/17/2022] Open
Abstract
Chlamydia trachomatis infections are the leading cause of sexually transmitted infections of bacterial origin. Lower genital tract infections are often asymptomatic, and therefore left untreated, leading to ascending infections that have long-term consequences on female reproductive health. Human pathology can be recapitulated in mice with the mouse adapted strain C. muridarum. Eight years into the post-genetic era, significant advances to expand the Chlamydia genetic toolbox have been made to facilitate the study of this important human pathogen. However, the need for additional tools remains, especially for C. muridarum. Here, we describe a new set of spectinomycin resistant E. coli-Chlamydia shuttle vectors, for C. trachomatis and C. muridarum. These versatile vectors allow for expression and localization studies of Chlamydia effectors, such as Inc proteins, and will be instrumental for mutant complementation studies. In addition, we have exploited the differential expression of specific Chlamydia genes during the developmental cycle to engineer an omcA::gfp fluorescent transcriptional reporter. This novel tool allows for monitoring RB to EB conversion at the bacterial level. Spatiotemporal tracking of GFP expression within individual inclusions revealed that RB to EB conversion initiates in bacteria located at the edge of the inclusion and correlates with the time post initiation of bacterial replication and inclusion size. Comparison between primary and secondary inclusions potentially suggests that the environment in which the inclusions develop influences the timing of conversion. Altogether, the Chlamydia genetic tools described here will benefit the field, as we continue to investigate the molecular mechanisms underlying Chlamydia-host interaction and pathogenesis.
Collapse
Affiliation(s)
- María Eugenia Cortina
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Rachel J. Ende
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - R. Clayton Bishop
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Charlie Bayne
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Isabelle Derré
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
- * E-mail:
| |
Collapse
|
11
|
Chronic Chlamydia infection in human organoids increases stemness and promotes age-dependent CpG methylation. Nat Commun 2019; 10:1194. [PMID: 30886143 PMCID: PMC6423033 DOI: 10.1038/s41467-019-09144-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 02/22/2019] [Indexed: 01/12/2023] Open
Abstract
Chronic infections of the fallopian tubes with Chlamydia trachomatis (Ctr) cause scarring and can lead to infertility. Here we use human fallopian tube organoids and genital Ctr serovars D, K and E for long-term in vitro analysis. The epithelial monolayer responds with active expulsion of the bacteria into the lumen and with compensatory cellular proliferation—demonstrating a role of epithelial homeostasis in the defense against this pathogen. In addition, Ctr infection activates LIF signaling, which we find to be an essential regulator of stemness in the organoids. Infected organoids exhibit a less differentiated phenotype with higher stemness potential, as confirmed by increased organoid forming efficiency. Moreover, Ctr increases hypermethylation of DNA, which is an indicator of accelerated molecular aging. Thus, the chronic organoid infection model suggests that Ctr has a long-term impact on the epithelium. These heritable changes might be a contributing factor in the development of tubal pathologies, including the initiation of high grade serous ovarian cancer. Chronic infections of the fallopian tubes with Chlamydia trachomatis can cause scarring and infertility. Here, the authors show that the pathogen alters stem cell differentiation and DNA methylation in human fallopian tube organoids, suggesting a potential link to cellular ageing and malignant transformation.
Collapse
|
12
|
O'Neill CE, Skilton RJ, Pearson SA, Filardo S, Andersson P, Clarke IN. Genetic Transformation of a C. trachomatis Ocular Isolate With the Functional Tryptophan Synthase Operon Confers an Indole-Rescuable Phenotype. Front Cell Infect Microbiol 2018; 8:434. [PMID: 30619780 PMCID: PMC6302012 DOI: 10.3389/fcimb.2018.00434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 11/30/2018] [Indexed: 11/13/2022] Open
Abstract
Chlamydia trachomatis is the leading cause of preventable blindness and the most common bacterial sexually transmitted infection. Different strains are associated with ocular or urogenital infections, and a proposed mechanism that may explain this tissue tropism is the active tryptophan biosynthesis pathway encoded by the genomic trpRBA operon in urogenital strains. Here we describe genetic complementation studies that are essential to confirm the role of tryptophan synthase in the context of an ocular C. trachomatis genomic background. Ocular strain A2497 was transformed with the (urogenital) pSW2::GFP shuttle vector showing that there is no strain tropism barrier to this plasmid vector; moreover, transformation had no detrimental effect on the growth kinetics of A2497, which is important given the low transformation efficiency of C. trachomatis. A derivative of the pSW2::GFP vector was used to deliver the active tryptophan biosynthesis genes from a urogenital strain of C. trachomatis (Soton D1) to A2497 with the aim of complementing the truncated trpA gene common to most ocular strains. After confirmation of intact TrpA protein expression in the transformed A2497, the resulting transformants were cultivated in tryptophan-depleted medium with and without indole or tryptophan, showing that complementation of the truncated trpA gene by the intact and functional urogenital trpRBA operon was sufficient to bestow an indole rescuable phenotype upon A2497. This study proves that pSW2::GFP derived vectors do not conform to the cross-strain transformation barrier reported for other chlamydia shuttle vectors, suggesting these as a universal vector for transformation of all C. trachomatis strains. This vector promiscuity enabled us to test the indole rescue hypothesis by transforming ocular strain A2497 with the functional urogenital trpRBA operon, which complemented the non-functional tryptophan synthase. These data confirm that the trpRBA operon is necessary and sufficient for chlamydia to survive in tryptophan-limited environments such as the female urogenital tract.
Collapse
Affiliation(s)
- Colette Elizabeth O'Neill
- Molecular Microbiology Group, Department of Clinical and Experimental Science, Southampton General Hospital, University Medical School, Southampton, United Kingdom
| | - Rachel Jane Skilton
- Molecular Microbiology Group, Department of Clinical and Experimental Science, Southampton General Hospital, University Medical School, Southampton, United Kingdom
| | - Sarah Ann Pearson
- Molecular Microbiology Group, Department of Clinical and Experimental Science, Southampton General Hospital, University Medical School, Southampton, United Kingdom
| | - Simone Filardo
- Section of Microbiology, Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy
| | - Patiyan Andersson
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Ian Nicholas Clarke
- Molecular Microbiology Group, Department of Clinical and Experimental Science, Southampton General Hospital, University Medical School, Southampton, United Kingdom
| |
Collapse
|
13
|
Shima K, Wanker M, Skilton RJ, Cutcliffe LT, Schnee C, Kohl TA, Niemann S, Geijo J, Klinger M, Timms P, Rattei T, Sachse K, Clarke IN, Rupp J. The Genetic Transformation of Chlamydia pneumoniae. mSphere 2018; 3:e00412-18. [PMID: 30305318 PMCID: PMC6180227 DOI: 10.1128/msphere.00412-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/11/2018] [Indexed: 11/26/2022] Open
Abstract
We demonstrate the genetic transformation of Chlamydia pneumoniae using a plasmid shuttle vector system which generates stable transformants. The equine C. pneumoniae N16 isolate harbors the 7.5-kb plasmid pCpnE1. We constructed the plasmid vector pRSGFPCAT-Cpn containing a pCpnE1 backbone, plus the red-shifted green fluorescent protein (RSGFP), as well as the chloramphenicol acetyltransferase (CAT) gene used for the selection of plasmid shuttle vector-bearing C. pneumoniae transformants. Using the pRSGFPCAT-Cpn plasmid construct, expression of RSGFP in koala isolate C. pneumoniae LPCoLN was demonstrated. Furthermore, we discovered that the human cardiovascular isolate C. pneumoniae CV-6 and the human community-acquired pneumonia-associated C. pneumoniae IOL-207 could also be transformed with pRSGFPCAT-Cpn. In previous studies, it was shown that Chlamydia spp. cannot be transformed when the plasmid shuttle vector is constructed from a different plasmid backbone to the homologous species. Accordingly, we confirmed that pRSGFPCAT-Cpn could not cross the species barrier in plasmid-bearing and plasmid-free C. trachomatis, C. muridarum, C. caviae, C. pecorum, and C. abortus However, contrary to our expectation, pRSGFPCAT-Cpn did transform C. felis Furthermore, pRSGFPCAT-Cpn did not recombine with the wild-type plasmid of C. felis Taken together, we provide for the first time an easy-to-handle transformation protocol for C. pneumoniae that results in stable transformants. In addition, the vector can cross the species barrier to C. felis, indicating the potential of horizontal pathogenic gene transfer via a plasmid.IMPORTANCE The absence of tools for the genetic manipulation of C. pneumoniae has hampered research into all aspects of its biology. In this study, we established a novel reproducible method for C. pneumoniae transformation based on a plasmid shuttle vector system. We constructed a C. pneumoniae plasmid backbone shuttle vector, pRSGFPCAT-Cpn. The construct expresses the red-shifted green fluorescent protein (RSGFP) fused to chloramphenicol acetyltransferase in C. pneumoniaeC. pneumoniae transformants stably retained pRSGFPCAT-Cpn and expressed RSGFP in epithelial cells, even in the absence of chloramphenicol. The successful transformation in C. pneumoniae using pRSGFPCAT-Cpn will advance the field of chlamydial genetics and is a promising new approach to investigate gene functions in C. pneumoniae biology. In addition, we demonstrated that pRSGFPCAT-Cpn overcame the plasmid species barrier without the need for recombination with an endogenous plasmid, indicating the potential probability of horizontal chlamydial pathogenic gene transfer by plasmids between chlamydial species.
Collapse
Affiliation(s)
- Kensuke Shima
- Department of Infectious Diseases and Microbiology, University of Luebeck, Luebeck, Germany
| | - Maximilian Wanker
- Department of Infectious Diseases and Microbiology, University of Luebeck, Luebeck, Germany
- German Center for Infection Research (DZIF), Partner Site, Hamburg-Luebeck-Borstel-Riems, Germany
| | - Rachel J Skilton
- Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, United Kingdom
| | - Lesley T Cutcliffe
- Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, United Kingdom
| | - Christiane Schnee
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-lnstitute (Federal Research Institute for Animal Health), Jena, Germany
| | - Thomas A Kohl
- German Center for Infection Research (DZIF), Partner Site, Hamburg-Luebeck-Borstel-Riems, Germany
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany
| | - Stefan Niemann
- German Center for Infection Research (DZIF), Partner Site, Hamburg-Luebeck-Borstel-Riems, Germany
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany
| | - Javier Geijo
- Division of Computational Systems Biology, University Vienna, Vienna, Austria
| | | | - Peter Timms
- University of Sunshine Coast, Maroochydore, Australia
| | - Thomas Rattei
- Division of Computational Systems Biology, University Vienna, Vienna, Austria
| | - Konrad Sachse
- RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Ian N Clarke
- Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, United Kingdom
| | - Jan Rupp
- Department of Infectious Diseases and Microbiology, University of Luebeck, Luebeck, Germany
- German Center for Infection Research (DZIF), Partner Site, Hamburg-Luebeck-Borstel-Riems, Germany
| |
Collapse
|
14
|
Khurshid S, Govada L, Wills G, McClure MO, Helliwell JR, Chayen NE. Chlamydia protein Pgp3 studied at high resolution in a new crystal form. IUCRJ 2018; 5:439-448. [PMID: 30002845 PMCID: PMC6038952 DOI: 10.1107/s2052252518007637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/22/2018] [Indexed: 06/08/2023]
Abstract
The protein Pgp3 is implicated in the sexually transmitted disease chlamydia and comprises an extended complex arrangement of a C-terminal domain (CTD) and an N-terminal domain (NTD) linked by a triple-helix coiled coil (THCC). Here, the X-ray crystal structure of Pgp3 from an LGV1 strain is reported at the highest X-ray diffraction resolution obtained to date for the full protein. The protein was crystallized using a high concentration of potassium bromide, which resulted in a new crystal form with relatively low solvent content that diffracted to a resolution of 1.98 Å. The three-dimensional structure of this new crystal form is described and compared with those of other crystal forms, and the potassium bromide binding sites and the relevance to chlamydia isolates from around the globe are described. The crystal packing is apparently driven by the CTDs. Since the threefold axes of the THCC and NTD are not collinear with the threefold axis of a CTD, this naturally leads to disorder in the THCC and the portion of the NTD that does not directly interact with the CTD via crystal packing. The key avenue to resolving these oddities in the crystal structure analysis was a complete new analysis in space group P1 and determining the space group as P212121. This space-group assignment was that originally determined from the diffraction pattern but was perhaps complicated by translational noncrystallographic symmetry. This crystal structure of a three-domain multi-macromolecular complex with two misaligned threefold axes was a unique challenge and has not been encountered before. It is suggested that a specific intermolecular interaction, possibly of functional significance in receptor binding in chlamydia, might allow the design of a new chemotherapeutic agent against chlamydia.
Collapse
Affiliation(s)
- Sahir Khurshid
- Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, England
| | - Lata Govada
- Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, England
| | - Gillian Wills
- Department of Medicine, Imperial College London, St Mary’s Campus, London W2 1PG, England
| | - Myra O. McClure
- Department of Medicine, Imperial College London, St Mary’s Campus, London W2 1PG, England
| | - John R. Helliwell
- School of Chemistry, The University of Manchester, Manchester M13 9PL, England
| | - Naomi E. Chayen
- Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, England
| |
Collapse
|
15
|
Skilton RJ, Wang Y, O'Neill C, Filardo S, Marsh P, Bénard A, Thomson NR, Ramsey KH, Clarke IN. The Chlamydia muridarum plasmid revisited : new insights into growth kinetics. Wellcome Open Res 2018; 3:25. [PMID: 29657985 PMCID: PMC5871946 DOI: 10.12688/wellcomeopenres.13905.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2018] [Indexed: 11/23/2022] Open
Abstract
Background: Research in chlamydial genetics is challenging because of its obligate intracellular developmental cycle.
In vivo systems exist that allow studies of different aspects of basic biology of chlamydiae, the murine
Chlamydia muridarum model is one of great importance and thus an essential research tool.
C. muridarum carries a plasmid that has a role in virulence. Our aim was to compare and contrast the
C. muridarum plasmid-free phenotype with that of a chromosomally isogenic plasmid-bearing strain, through the inclusion phase of the developmental cycle. Methods: We measured infectivity for plasmid bearing and plasmid-cured
C. muridarum by inclusion forming assays in McCoy cells and in parallel bacterial chromosome replication by quantitative PCR, throughout the developmental cycle. In addition to these studies, we have carefully monitored chlamydial inclusion formation by confocal microscopy and transmission electron microscopy. A new
E.coli/chlamydial shuttle vector (pNigg::GFP) was constructed using standard cloning technology and used to transform
C. muridarum for further phenotypic studies. Results: We have advanced the definition of the chlamydial phenotype away from the simple static observation of mature inclusions and redefined the
C. muridarum plasmid-based phenotype on growth profile and inclusion morphology. Our observations on the growth properties of plasmid-cured
C. muridarum challenge the established interpretations, especially with regard to inclusion growth kinetics. Introduction of the shuttle plasmid pNigg::GFP into plasmid-cured
C. muridarum restored the wild-type plasmid-bearing phenotype and confirmed that loss of the plasmid was the sole cause for the changes in growth and chromosomal replication. Conclusions: Accurate growth curves and sampling at multiple time points throughout the developmental cycle is necessary to define plasmid phenotypes. There are subtle but important (previously unnoticed) differences in the overall growth profile of plasmid-bearing and plasmid-free
C. muridarum. We have proven that the differences described are solely due to the plasmid pNigg.
Collapse
Affiliation(s)
- Rachel J Skilton
- Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Yibing Wang
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Colette O'Neill
- Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Simone Filardo
- Department of Public Health and Infectious Diseases, Section of Microbiology, Sapienza University, Rome, Italy
| | - Peter Marsh
- Public Health England, Public Health Laboratory Southampton, Southampton General Hospital, Southampton, UK
| | - Angèle Bénard
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Nicholas R Thomson
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK.,London School of Hygiene and Tropical Medicine, London, UK
| | - Kyle H Ramsey
- Department of Microbiology & Immunology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, USA
| | - Ian N Clarke
- Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| |
Collapse
|
16
|
Transformation of Chlamydia: current approaches and impact on our understanding of chlamydial infection biology. Microbes Infect 2018; 20:445-450. [PMID: 29409975 DOI: 10.1016/j.micinf.2018.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 01/04/2018] [Accepted: 01/05/2018] [Indexed: 12/11/2022]
Abstract
The intonation "The king is dead, long live the king" aptly describes the state of Chlamydia research. Genetic-based approaches are rapidly replacing correlative strategies to provide new insights. We describe how current transformation technologies are enhancing progress in understanding Chlamydia infection biology and present key opportunities for further development.
Collapse
|
17
|
Abstract
Species of Chlamydia are the etiologic agent of endemic blinding trachoma, the leading cause of bacterial sexually transmitted diseases, significant respiratory pathogens, and a zoonotic threat. Their dependence on an intracellular growth niche and their peculiar developmental cycle are major challenges to elucidating their biology and virulence traits. The last decade has seen tremendous advances in our ability to perform a molecular genetic analysis of Chlamydia species. Major achievements include the generation of large collections of mutant strains, now available for forward- and reverse-genetic applications, and the introduction of a system for plasmid-based transformation enabling complementation of mutations; expression of foreign, modified, or reporter genes; and even targeted gene disruptions. This review summarizes the current status of the molecular genetic toolbox for Chlamydia species and highlights new insights into their biology and new challenges in the nascent field of Chlamydia genetics.
Collapse
Affiliation(s)
- Barbara S Sixt
- Department for Molecular Genetics and Microbiology, Duke University, Durham, North Carolina 27710; .,Centre de Recherche des Cordeliers, INSERM U1138, Paris 75006, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France.,Université Pierre et Marie Curie, Paris 75005, France
| | - Raphael H Valdivia
- Department for Molecular Genetics and Microbiology, Duke University, Durham, North Carolina 27710;
| |
Collapse
|
18
|
Shao L, Melero J, Zhang N, Arulanandam B, Baseman J, Liu Q, Zhong G. The cryptic plasmid is more important for Chlamydia muridarum to colonize the mouse gastrointestinal tract than to infect the genital tract. PLoS One 2017; 12:e0177691. [PMID: 28542376 PMCID: PMC5444651 DOI: 10.1371/journal.pone.0177691] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 05/02/2017] [Indexed: 02/07/2023] Open
Abstract
Chlamydia has been detected in the gastrointestinal tracts of both animals and humans. However, the mechanism by which Chlamydia colonizes the gut remains unclear. Chlamydia muridarum is known to spread from the genital to the gastrointestinal tracts hematogenously. The C. muridarum plasmid is a key pathogenic determinant in the mouse upper genital tract although plasmid-deficient C. muridarum is still able to colonize the upper genital tract. We now report that plasmid-deficient C. muridarum exhibits significantly delayed/reduced spreading from the mouse genital to the gastrointestinal tracts. C. muridarum with or without plasmid maintained similar levels in the mouse circulatory system following intravenous inoculation but the hematogenous plasmid-deficient C. muridarum was significantly less efficient in colonizing the gastrointestinal tract. Consistently, plasmid-deficient C. muridarum failed to restore normal colonization in the gastrointestinal tract even after intragastric inoculation at a high dose. Thus, we have demonstrated a plasmid-dependent colonization of C. muridarum in the gastrointestinal tract, supporting the concept that C. muridarum may have acquired the plasmid for adaptation to the mouse gastrointestinal tract during oral-fecal transmission. Since the plasmid is more important for C. muridarum to colonize the gastrointestinal tract than to infect the genital tract, the current study has laid a foundation for further defining the host pathways targeted by the plasmid-encoded or -regulated chlamydial effectors.
Collapse
Affiliation(s)
- Lili Shao
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Dermatovenereology, Tianjin Medical University General Hospital, Tianjin, China
| | - Jose Melero
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Nu Zhang
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Bernard Arulanandam
- Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Joel Baseman
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Quanzhong Liu
- Department of Dermatovenereology, Tianjin Medical University General Hospital, Tianjin, China
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| |
Collapse
|
19
|
Advances and Obstacles in the Genetic Dissection of Chlamydial Virulence. Curr Top Microbiol Immunol 2017; 412:133-158. [PMID: 29090367 DOI: 10.1007/82_2017_76] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Obligate intracellular pathogens in the family Chlamydiaceae infect taxonomically diverse eukaryotes ranging from amoebae to mammals. However, many fundamental aspects of chlamydial cell biology and pathogenesis remain poorly understood. Genetic dissection of chlamydial biology has historically been hampered by a lack of genetic tools. Exploitation of the ability of chlamydia to recombine genomic material by lateral gene transfer (LGT) ushered in a new era in chlamydia research. With methods to map mutations in place, genetic screens were able to assign functions and phenotypes to specific chlamydial genes. Development of an approach for stable transformation of chlamydia also provided a mechanism for gene delivery and platforms for disrupting chromosomal genes. Here, we explore how these and other tools have been used to test hypotheses concerning the functions of known chlamydial virulence factors and discover the functions of completely uncharacterized genes. Refinement and extension of the existing genetic tools to additional Chlamydia spp. will substantially advance understanding of the biology and pathogenesis of this important group of pathogens.
Collapse
|
20
|
Zhong G. Chlamydial Plasmid-Dependent Pathogenicity. Trends Microbiol 2016; 25:141-152. [PMID: 27712952 DOI: 10.1016/j.tim.2016.09.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/11/2016] [Accepted: 09/19/2016] [Indexed: 10/20/2022]
Abstract
Most Chlamydia species carry a 7.5kb plasmid encoding eight open reading frames conventionally called plasmid glycoproteins 1-8 or pGP1-8. Although the plasmid is not critical for chlamydial growth in vitro, its role in chlamydial pathogenesis is clearly demonstrated in the genital tracts of mice infected with Chlamydia muridarum, a model for investigating the human pathogen Chlamydia trachomatis. Plasmid-free C. trachomatis is also attenuated in both the mouse genital tract and nonhuman primate ocular tissue. Deficiency in pGP3 alone, which is regulated by pGP4, largely reproduced the in vivo but not in vitro phenotypes of the plasmid-free organisms, suggesting that pGP3 is a key in vivo virulence factor. The positive and negative regulations of some chromosomal genes by pGP4 and pGP5, respectively, may allow the plasmid to promote chlamydial adaptation to varied animal tissue environments. The focus of this review is to summarize the progress on the pathogenic functions of the plasmid-encoded open reading frames, which may motivate further investigation of the molecular mechanisms of chlamydial pathogenicity and development of medical utility of the chlamydial plasmid system.
Collapse
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.
| |
Collapse
|
21
|
Abstract
Etiology, transmission and protection: Chlamydia
trachomatis is the leading cause of bacterial sexually transmitted
infection (STI) globally. However, C. trachomatis also causes
trachoma in endemic areas, mostly Africa and the Middle East, and is a leading
cause of preventable blindness worldwide. Epidemiology, incidence and
prevalence: The World Health Organization estimates 131 million
new cases of C. trachomatis genital infection occur annually.
Globally, infection is most prevalent in young women and men (14-25 years),
likely driven by asymptomatic infection, inadequate partner treatment and
delayed development of protective immunity.
Pathology/Symptomatology: C.
trachomatis infects susceptible squamocolumnar or transitional
epithelial cells, leading to cervicitis in women and urethritis in men. Symptoms
are often mild or absent but ascending infection in some women may lead to
Pelvic Inflammatory Disease (PID), resulting in reproductive sequelae such as
ectopic pregnancy, infertility and chronic pelvic pain. Complications of
infection in men include epididymitis and reactive arthritis.
Molecular mechanisms of infection: Chlamydiae
manipulate an array of host processes to support their obligate intracellular
developmental cycle. This leads to activation of signaling pathways resulting in
disproportionate influx of innate cells and the release of tissue damaging
proteins and pro-inflammatory cytokines. Treatment and
curability: Uncomplicated urogenital infection is treated with
azithromycin (1 g, single dose) or doxycycline (100 mg twice daily x 7 days).
However, antimicrobial treatment does not ameliorate established disease. Drug
resistance is rare but treatment failures have been described. Development of an
effective vaccine that protects against upper tract disease or that limits
transmission remains an important goal.
Collapse
Affiliation(s)
- Catherine M O'Connell
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Morgan E Ferone
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| |
Collapse
|
22
|
Liang M, Wen Y, Ran O, Chen L, Wang C, Li L, Xie Y, Zhang Y, Chen C, Wu Y. Protective immunity induced by recombinant protein CPSIT_p8 of Chlamydia psittaci. Appl Microbiol Biotechnol 2016; 100:6385-6393. [PMID: 27052378 DOI: 10.1007/s00253-016-7494-8] [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: 01/14/2016] [Revised: 03/17/2016] [Accepted: 03/22/2016] [Indexed: 10/22/2022]
Abstract
Chlamydia psittaci is a zoonotic pathogen with a broad host range that can lead to severe respiratory and systemic disease in humans. Currently, an effective commercial vaccine against C. psittaci infection is not available. The chlamydial plasmid is an important virulence factor and encodes plasmid proteins that play important roles in chlamydial infection and the corresponding immune response. In this study, we assessed the efficacy of vaccination with plasmid proteins at preventing C. psittaci lung infection in a murine model. BALB/c mice were immunized intraperitoneally, three times at 2-week intervals, with purified recombinant CPSIT_p8 protein and then infected with C. psittaci. Immunization significantly decreased chlamydial load in the lungs of infected mice, resulted in a lower level of IFN-γ, and reduced the extent of inflammation. In vivo or in vitro neutralization of C. psittaci with sera collected from immunized mice did not reduce the amount of viable C. psittaci in the lungs of mice, indicating that CPSIT_p8-specific antibodies do not have neutralizing capacity. Furthermore, confocal fluorescence microscopy using a mouse anti-CPSIT_p8 antibody revealed that CPSIT_p8 was localized inside the inclusion of C. psittaci 6BC-infected cells. Our results demonstrate that CPSIT_p8 protein induces significant protective immunity against challenge with C. psittaci in mice and represents a promising new vaccine candidate for the prevention of C. psittaci infection.
Collapse
Affiliation(s)
- Mingxing Liang
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, 421001, China
| | - Yating Wen
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China
| | - Ou Ran
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China.,Department of Clinical Laboratory, Central Hospital of Xiangtan, Xiangtan, 411100, China
| | - Liesong Chen
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China
| | - Chuan Wang
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China
| | - Li Li
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China
| | - Yafeng Xie
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China
| | - Yang Zhang
- Department of Pathology, University of South China, Hengyang, 421001, China
| | - Chaoqun Chen
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China. .,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, 421001, China.
| | - Yimou Wu
- Pathogenic Biology Institute, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, 421001, China. .,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, 421001, China.
| |
Collapse
|
23
|
Abstract
Chlamydia spp. are ubiquitous, obligate, intracellular Gram-negative bacterial pathogens that undergo a unique biphasic developmental cycle transitioning between the infectious, extracellular elementary body and the replicative, intracellular reticulate body. The primary Chlamydia species associated with human disease are C. trachomatis, which is the leading cause of both reportable bacterial sexually transmitted infections and preventable blindness, and C. pneumoniae, which infects the respiratory tract and is associated with cardiovascular disease. Collectively, these pathogens are a significant source of morbidity and pose a substantial financial burden on the global economy. Past efforts to elucidate virulence mechanisms of these unique and important pathogens were largely hindered by an absence of genetic methods. Watershed studies in 2011 and 2012 demonstrated that forward and reverse genetic approaches were feasible with Chlamydia and that shuttle vectors could be selected and maintained within the bacterium. While these breakthroughs have led to a steady expansion of the chlamydial genetic tool kit, there are still roads left to be traveled. This minireview provides a synopsis of the currently available genetic methods for Chlamydia along with a comparison to the methods used in other obligate intracellular bacteria. Limitations and advantages of these techniques will be discussed with an eye toward the methods still needed, and how the current state of the art for genetics in obligate intracellular bacteria could direct future technological advances for Chlamydia.
Collapse
|
24
|
Lowden NM, Yeruva L, Johnson CM, Bowlin AK, Fisher DJ. Use of aminoglycoside 3' adenyltransferase as a selection marker for Chlamydia trachomatis intron-mutagenesis and in vivo intron stability. BMC Res Notes 2015; 8:570. [PMID: 26471806 PMCID: PMC4606545 DOI: 10.1186/s13104-015-1542-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/05/2015] [Indexed: 12/14/2022] Open
Abstract
Background Chlamydia spp. are obligate, intracellular bacteria that infect humans and animals. Research on these important pathogens has been hindered due to a paucity of genetic tools. We recently adapted a group II intron (GII) mutagenesis platform for creation of ampicillin-selectable gene insertions in C. trachomatis L2. The aims of this study were: (1) to assess the stability of the intron-insertion in an in vivo infection model to gauge the efficacy of this genetic tool for long term animal studies and (2) to expand upon the utility of the method by validating a second selection marker (aadA, conferring spectinomycin resistance) for mutant construction. Results Intron stability was assessed using a mouse vaginal tract infection model with a C. trachomatis L2 434/Bu incA::GII(bla) mutant. Infections were performed in the absence of selection and isolates shed into the vaginal tract were isolated and expanded in cell culture (also without selection). PCR and inclusion phenotype analysis indicated that the intron was stable for at least 27 days post-infection (at which point bacteria were no longer recovered from the mouse). The aminoglycoside 3′ adenyltransferase (aadA) gene was used to create a spectinomycin-selectable GII intron, facilitating the construction of an incA::GII[aadA] C. trachomatis L2 insertion mutant. Both the GII(aadA) intron and our previously reported GII(bla) intron were then used to create an incA::GII(aadA), rsbV1::GII(bla) double mutant. Mutants were confirmed via PCR, sequencing, inclusion morphology (incA only), and western blot. Conclusions The stability of the intron-insertion during in vivo growth indicates that the GII-insertion mutants can be used to study pathogenesis using the well-established mouse infection model. In addition, the validation of an additional marker for mutagenesis in Chlamydia allows for gene complementation approaches and construction of targeted, double mutants in Chlamydia. The aadA marker also could be useful for other genetic methods. Collectively, our results expand upon the rapidly growing chlamydial genetic toolkit and will aid in the implementation of studies dissecting the contribution of individual genes to infection. Electronic supplementary material The online version of this article (doi:10.1186/s13104-015-1542-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Nicole M Lowden
- Department of Microbiology, Southern Illinois University, 1125 Lincoln Drive, Carbondale, IL, 62901, USA.
| | - Laxmi Yeruva
- Departments of Pediatrics, Arkansas Children's Hospital Research Institute, Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, AR, 72202, USA.
| | - Cayla M Johnson
- Department of Microbiology, Southern Illinois University, 1125 Lincoln Drive, Carbondale, IL, 62901, USA.
| | - Anne K Bowlin
- Departments of Pediatrics, Arkansas Children's Hospital Research Institute, Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, AR, 72202, USA.
| | - Derek J Fisher
- Department of Microbiology, Southern Illinois University, 1125 Lincoln Drive, Carbondale, IL, 62901, USA.
| |
Collapse
|
25
|
Borges V, Gomes JP. Deep comparative genomics among Chlamydia trachomatis lymphogranuloma venereum isolates highlights genes potentially involved in pathoadaptation. INFECTION GENETICS AND EVOLUTION 2015; 32:74-88. [PMID: 25745888 DOI: 10.1016/j.meegid.2015.02.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/23/2015] [Accepted: 02/26/2015] [Indexed: 11/19/2022]
Abstract
Lymphogranuloma venereum (LGV) is a human sexually transmitted disease caused by the obligate intracellular bacterium Chlamydia trachomatis (serovars L1-L3). LGV clinical manifestations range from severe ulcerative proctitis (anorectal syndrome), primarily caused by the epidemic L2b strains, to painful inguinal lymphadenopathy (the typical LGV bubonic form). Besides potential host-related factors, the differential disease severity and tissue tropism among LGV strains is likely a function of the genetic backbone of the strains. We aimed to characterize the genetic variability among LGV strains as strain- or serovar-specific mutations may underlie phenotypic signatures, and to investigate the mutational events that occurred throughout the pathoadaptation of the epidemic L2b lineage. By analyzing 20 previously published genomes from L1, L2, L2b and L3 strains and two new genomes from L2b strains, we detected 1497 variant sites and about 100 indels, affecting 453 genes and 144 intergenic regions, with 34 genes displaying a clear overrepresentation of nonsynonymous mutations. Effectors and/or type III secretion substrates (almost all of those described in the literature) and inclusion membrane proteins showed amino acid changes that were about fivefold more frequent than silent changes. More than 120 variant sites occurred in plasmid-regulated virulence genes, and 66% yielded amino acid changes. The identified serovar-specific variant sites revealed that the L2b-specific mutations are likely associated with higher fitness and pointed out potential targets for future highly discriminatory diagnostic/typing tests. By evaluating the evolutionary pathway beyond the L2b clonal radiation, we observed that 90.2% of the intra-L2b variant sites occurring in coding regions involve nonsynonymous mutations, where CT456/tarp has been the main target. Considering the progress on C. trachomatis genetic manipulation, this study may constitute an important contribution for prioritizing study targets for functional genomics aiming to dissect the impact of the identified intra-LGV polymorphisms on virulence or tropism dissimilarities among LGV strains.
Collapse
Affiliation(s)
- Vítor Borges
- Reference Laboratory of Bacterial Sexually Transmitted Infections, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - João Paulo Gomes
- Reference Laboratory of Bacterial Sexually Transmitted Infections, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
| |
Collapse
|
26
|
Plasmid CDS5 influences infectivity and virulence in a mouse model of Chlamydia trachomatis urogenital infection. Infect Immun 2014; 82:3341-9. [PMID: 24866804 DOI: 10.1128/iai.01795-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The native plasmid of both Chlamydia muridarum and Chlamydia trachomatis has been shown to control virulence and infectivity in mice and in lower primates. We recently described the development of a plasmid-based genetic transformation protocol for Chlamydia trachomatis that for the first time provides a platform for the molecular dissection of the function of the chlamydial plasmid and its individual genes or coding sequences (CDS). In the present study, we transformed a plasmid-free lymphogranuloma venereum isolate of C. trachomatis, serovar L2, with either the original shuttle vector (pGFP::SW2) or a derivative of pGFP::SW2 carrying a deletion of the plasmid CDS5 gene (pCDS5KO). Female mice were inoculated with these strains either intravaginally or transcervically. We found that transformation of the plasmid-free isolate with the intact pGFP::SW2 vector significantly enhanced infectivity and induction of host inflammatory responses compared to the plasmid-free parental isolate. Transformation with pCDS5KO resulted in infection courses and inflammatory responses not significantly different from those observed in mice infected with the plasmid-free isolate. These results indicate a critical role of plasmid CDS5 in in vivo fitness and in induction of inflammatory responses. To our knowledge, these are the first in vivo observations ascribing infectivity and virulence to a specific plasmid gene.
Collapse
|
27
|
Wang Y, Cutcliffe LT, Skilton RJ, Ramsey KH, Thomson NR, Clarke IN. The genetic basis of plasmid tropism between Chlamydia trachomatis and Chlamydia muridarum. Pathog Dis 2014; 72:19-23. [PMID: 24700815 PMCID: PMC4314687 DOI: 10.1111/2049-632x.12175] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/26/2014] [Accepted: 03/26/2014] [Indexed: 11/30/2022] Open
Abstract
The development of genetic transformation technology for Chlamydia trachomatis using its endogenous plasmid has recently been described. Chlamydia muridarum cannot be transformed by the C. trachomatis plasmid, indicating a barrier between chlamydial species. To determine which regions of the plasmid conferred the species specificity, we used the novel approach of transforming wild-type C. muridarum carrying the endogenous plasmid pNigg and forced recombination with the C. trachomatis vector pGFP::SW2 which carries the complete C. trachomatis plasmid (pSW2). Penicillin and chloramphenicol-resistant transformants expressing the green fluorescent protein were selected. Recovery of plasmids from these transformants showed they were recombinants. The differences between the pSW2 and pNigg allowed identification of the recombination breakpoints and showed that pGFP::SW2 had exchanged a ∼ 1 kbp region with pNigg covering CDS 2. The recombinant plasmid (pSW2NiggCDS2) is maintained under antibiotic selection when transformed into plasmid-cured C. muridarum. The ability to select for recombinants in C. muridarum shows that the barrier is not at transformation, but at the level of plasmid replication or maintenance. Our studies show that CDS 2, together with adjoining sequences, is the main determinant of plasmid tropism.
Collapse
Affiliation(s)
- Yibing Wang
- Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | | | | | | | | | | |
Collapse
|
28
|
Transformation of Chlamydia muridarum reveals a role for Pgp5 in suppression of plasmid-dependent gene expression. J Bacteriol 2013; 196:989-98. [PMID: 24363344 DOI: 10.1128/jb.01161-13] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Transformation of Chlamydia trachomatis should greatly advance the chlamydial research. However, significant progress has been hindered by the failure of C. trachomatis to induce clinically relevant pathology in animal models. Chlamydia muridarum, which naturally infects mice, can induce hydrosalpinx in mice, a tubal pathology also seen in women infected with C. trachomatis. We have developed a C. muridarum transformation system and confirmed Pgp1, -2, -6, and -8 as plasmid maintenance factors, Pgp3, -5, and -7 as dispensable for in vitro growth, and Pgp4 as a positive regulator of genes that are dependent on plasmid for expression. More importantly, we have discovered that Pgp5 can negatively regulate the same plasmid-dependent genes. Deletion of Pgp5 led to a significant increase in expression of the plasmid-dependent genes, suggesting that Pgp5 can suppress the expression of these genes. Replacement of pgp5 with a mCherry gene, or premature termination of pgp5 translation, also increased expression of the plasmid-dependent genes, indicating that Pgp5 protein but not its DNA sequence is required for the inhibitory effect. Replacing C. muridarum pgp5 with a C. trachomatis pgp5 still inhibited the plasmid-dependent gene expression, indicating that the negative regulation of plasmid-dependent genes is a common feature of all Pgp5 regardless of its origin. Nevertheless, C. muridarum Pgp5 is more potent than C. trachomatis Pgp5 in suppressing gene expression. Thus, we have uncovered a novel function of Pgp5 and developed a C. muridarum transformation system for further mapping chlamydial pathogenic and protective determinants in animal models.
Collapse
|