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Macromolecular Conjugate and Biological Carrier Approaches for the Targeted Delivery of Antibiotics. Antibiotics (Basel) 2017; 6:antibiotics6030014. [PMID: 28677631 PMCID: PMC5617978 DOI: 10.3390/antibiotics6030014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/24/2017] [Accepted: 06/29/2017] [Indexed: 01/21/2023] Open
Abstract
For the past few decades, the rapid rise of antibiotic multidrug-resistance has presented a palpable threat to human health worldwide. Meanwhile, the number of novel antibiotics released to the market has been steadily declining. Therefore, it is imperative that we utilize innovative approaches for the development of antimicrobial therapies. This article will explore alternative strategies, namely drug conjugates and biological carriers for the targeted delivery of antibiotics, which are often eclipsed by their nanomedicine-based counterparts. A variety of macromolecules have been investigated as conjugate carriers, but only those most widely studied in the field of infectious diseases (e.g., proteins, peptides, antibodies) will be discussed in detail. For the latter group, blood cells, especially erythrocytes, have been successfully tested as homing carriers of antimicrobial agents. Bacteriophages have also been studied as a candidate for similar functions. Once these alternative strategies receive the amount of research interest and resources that would more accurately reflect their latent applicability, they will inevitably prove valuable in the perennial fight against antibiotic resistance.
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202
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Wan FYM, Enciso GA. Optimal Proliferation and Differentiation of Chlamydia Trachomatis. STUDIES IN APPLIED MATHEMATICS (CAMBRIDGE, MASS.) 2017; 139:129-178. [PMID: 28989185 PMCID: PMC5627525 DOI: 10.1111/sapm.12175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Chlamydia trachomatis is a bacterium that causes eye infection and blindness in humans. It has an unusual life cycle involving two developmental forms. Within a cytoplasmic inclusion, the reticulate body (RB) repeatedly divides by binary fission and asynchronously differentiates into the infectious elementary body (EB). Upon the death of the mammalian cell that host many such inclusions, only the EB form of the bacteria survive and proceed to infect other cells. Given the bacteria's fast spreading infection, conventional wisdom would have the few initial EB turn into RB, divide and proliferate first, and then eventually start converting in order to maximize the terminal EB population upon host cell lysis. Several biological processes are seen as possible mechanisms for implementing such a conversion strategy. However, the optimality of an instinctual strategy with a period of proliferate without conversion prior to the onset of differentiation has never been substantiated theoretically or justified mathematically. This paper formulates three relatively simple models that capture the essential features of the Chlamydia life cycle. When the initial infection is caused by the endocytosis of a small EB population well below the carrying capacity of the host cell, the Maximum Principle requires for these models an optimal conversion strategy that confirms and rigorously justifies the prevailing view of no conversion at the early stage of the host cell infection. However, the conventional supposition is found to be inappropriate for an initial EB (-to-RB) population near or above the carrying capacity. Previously suggested and new biological mechanisms are examined for their role in implementing the different optimal conversion strategies associated with models investigated herein.
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Affiliation(s)
- Frederic Y M Wan
- Department of Mathematics, University of California, Irvine, CA 92697
| | - Germán A Enciso
- Department of Mathematics, University of California, Irvine, CA 92697
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203
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Collingro A, Köstlbacher S, Mussmann M, Stepanauskas R, Hallam SJ, Horn M. Unexpected genomic features in widespread intracellular bacteria: evidence for motility of marine chlamydiae. ISME JOURNAL 2017. [PMID: 28644443 PMCID: PMC5604735 DOI: 10.1038/ismej.2017.95] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Chlamydiae are obligate intracellular bacteria comprising important human pathogens and symbionts of protists. Molecular evidence indicates a tremendous diversity of chlamydiae particularly in marine environments, yet our current knowledge is based mainly on terrestrial representatives. Here we provide first insights into the biology of marine chlamydiae representing three divergent clades. Our analysis of single-cell amplified genomes revealed hallmarks of the chlamydial lifestyle, supporting the ancient origin of their characteristic developmental cycle and major virulence mechanisms. Surprisingly, these chlamydial genomes encode a complete flagellar apparatus, a previously unreported feature. We show that flagella are an ancient trait that was subject to differential gene loss among extant chlamydiae. Together with a chemotaxis system, these marine chlamydiae are likely motile, with flagella potentially playing a role during host cell infection. This study broadens our view on chlamydial biology and indicates a largely underestimated potential to adapt to different hosts and environments.
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Affiliation(s)
- Astrid Collingro
- Department of Microbial and Ecosystems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Stephan Köstlbacher
- Department of Microbial and Ecosystems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Marc Mussmann
- Department of Microbial and Ecosystems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | | | - Steven J Hallam
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada.,Genome Science and Technology Program, University of British Columbia, Vancouver, British Columbia, Canada.,Graduate Program in Bioinformatics, University of British Columbia, Vancouver, British Columbia, Canada.,Peter Wall Institute for Advanced Studies, University of British Columbia, Vancouver, British Columbia, Canada.,ECOSCOPE Training Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthias Horn
- Department of Microbial and Ecosystems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
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204
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Marsh JW, Ong VA, Lott WB, Timms P, Tyndall JDA, Huston WM. CtHtrA: the lynchpin of the chlamydial surface and a promising therapeutic target. Future Microbiol 2017; 12:817-829. [PMID: 28593794 DOI: 10.2217/fmb-2017-0017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection worldwide and the leading cause of preventable blindness. Reports have emerged of treatment failure, suggesting a need to develop new antibiotics to battle Chlamydia infection. One possible candidate for a new treatment is the protease inhibitor JO146, which is an effective anti-Chlamydia agent that targets the CtHtrA protein. CtHtrA is a lynchpin on the chlamydial cell surface due to its essential and multifunctional roles in the bacteria's stress response, replicative phase of development, virulence and outer-membrane protein assembly. This review summarizes the current understanding of CtHtrA function and presents a mechanistic model that highlights CtHtrA as an effective target for anti-Chlamydia drug development.
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Affiliation(s)
- James W Marsh
- The ithree institute, University of Technology Sydney, Ultimo, 2007, NSW, Australia
| | - Vanissa A Ong
- Institute of Health & Biomedical Innovation (IHBI), Queensland University of Technology (QUT), Brisbane, 4059, QLD, Australia
| | - William B Lott
- Institute of Health & Biomedical Innovation (IHBI), Queensland University of Technology (QUT), Brisbane, 4059, QLD, Australia
| | - Peter Timms
- Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Sippy Downs, 4558, QLD, Australia
| | - Joel DA Tyndall
- National School of Pharmacy, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Wilhelmina M Huston
- School of Life Sciences, University of Technology Sydney, Ultimo, 2007, NSW, Australia
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205
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Biphasic Metabolism and Host Interaction of a Chlamydial Symbiont. mSystems 2017; 2:mSystems00202-16. [PMID: 28593198 PMCID: PMC5451489 DOI: 10.1128/msystems.00202-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/03/2017] [Indexed: 11/20/2022] Open
Abstract
Chlamydiae are obligate intracellular bacteria comprising well-known human pathogens and ubiquitous symbionts of protists, which are characterized by a unique developmental cycle. Here we comprehensively analyzed gene expression dynamics of Protochlamydia amoebophila during infection of its Acanthamoeba host by RNA sequencing. This revealed a highly dynamic transcriptional landscape, where major transcriptional shifts are conserved among chlamydial symbionts and pathogens. Our data served to propose a time-resolved model for type III protein secretion during the developmental cycle, and we provide evidence for a biphasic metabolism of P. amoebophila during infection, which involves energy parasitism and amino acids as the carbon source during initial stages and a postreplicative switch to endogenous glucose-based ATP production. This fits well with major transcriptional changes in the amoeba host, where upregulation of complex sugar breakdown precedes the P. amoebophila metabolic switch. The biphasic chlamydial metabolism represents a unique adaptation to exploit eukaryotic host cells, which likely contributed to the evolutionary success of this group of microbes. IMPORTANCE Chlamydiae are known as major bacterial pathogens of humans, causing the ancient disease trachoma, but they are also frequently found in the environment where they infect ubiquitous protists such as amoebae. All known chlamydiae require a eukaryotic host cell to thrive. Using the environmental chlamydia Protochlamydia amoebophila within its natural host, Acanthamoeba castellanii, we investigated gene expression dynamics in vivo and throughout the complete chlamydial developmental cycle for the first time. This allowed us to infer how a major virulence mechanism, the type III secretion system, is regulated and employed, and we show that the physiology of chlamydiae undergoes a complete shift regarding carbon metabolism and energy generation. This study provides comprehensive insights into the infection strategy of chlamydiae and reveals a unique adaptation to life within a eukaryotic host cell.
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206
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Biochemical and Genetic Analysis of the Chlamydia GroEL Chaperonins. J Bacteriol 2017; 199:JB.00844-16. [PMID: 28396349 DOI: 10.1128/jb.00844-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 04/01/2017] [Indexed: 02/01/2023] Open
Abstract
Chaperonins are essential for cellular growth under normal and stressful conditions and consequently represent one of the most conserved and ancient protein classes. The paradigm Escherichia coli chaperonin, EcGroEL, and its cochaperonin, EcGroES, assist in the folding of proteins via an ATP-dependent mechanism. In addition to the presence of groEL and groES homologs, groEL paralogs are found in many bacteria, including pathogens, and have evolved poorly understood species-specific functions. Chlamydia spp., which are obligate intracellular bacteria, have reduced genomes that nonetheless contain three groEL genes, Chlamydia groEL (ChgroEL), ChgroEL2, and ChgroEL3 We hypothesized that ChGroEL is the bona fide chaperonin and that the paralogs perform novel Chlamydia-specific functions. To test our hypothesis, we investigated the biochemical properties of ChGroEL and its cochaperonin, ChGroES, and queried the in vivo essentiality of the three ChgroEL genes through targeted mutagenesis in Chlamydia trachomatis ChGroEL hydrolyzed ATP at a rate 25% of that of EcGroEL and bound with high affinity to ChGroES, and the ChGroEL-ChGroES complex could refold malate dehydrogenase (MDH). The chlamydial ChGroEL was selective for its cognate cochaperonin, ChGroES, while EcGroEL could function with both EcGroES and ChGroES. A P35T ChGroES mutant (ChGroESP35T) reduced ChGroEL-ChGroES interactions and MDH folding activities but was tolerated by EcGroEL. Both ChGroEL-ChGroES and EcGroEL-ChGroESP35T could complement an EcGroEL-EcGroES mutant. Finally, we successfully inactivated both paralogs but not ChgroEL, leading to minor growth defects in cell culture that were not exacerbated by heat stress. Collectively, our results support novel functions for the paralogs and solidify ChGroEL as a bona fide chaperonin that is biochemically distinct from EcGroEL.IMPORTANCEChlamydia is an important cause of human diseases, including pneumonia, sexually transmitted infections, and trachoma. The chlamydial chaperonin ChGroEL and chaperonin paralog ChGroEL2 have been associated with survival under stress conditions, and ChGroEL is linked with immunopathology elicited by chlamydial infections. However, their exact roles in bacterial survival and disease remain unclear. Our results further substantiate the hypotheses that ChGroEL is the primary chlamydial chaperonin and that the paralogs play specialized roles during infection. Furthermore, ChGroEL and the mitochondrial GroEL only functioned with their cochaperonin, in contrast to the promiscuous nature of GroEL from E. coli and Helicobacter pylori, which might indicate a divergent evolution of GroEL during the transition from a free-living organism to an obligate intracellular lifestyle.
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207
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Vodstrcil LA, Rupasinghe TWT, Kong FYS, Tull D, Worthington K, Chen MY, Huston WM, Timms P, McConville MJ, Fairley CK, Bradshaw CS, Tabrizi SN, Hocking JS. Measurement of tissue azithromycin levels in self-collected vaginal swabs post treatment using liquid chromatography and tandem mass spectrometry (LC-MS/MS). PLoS One 2017; 12:e0177615. [PMID: 28498845 PMCID: PMC5428968 DOI: 10.1371/journal.pone.0177615] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 04/30/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Azithromycin is recommended for the treatment of uncomplicated urogenital chlamydia infection although the standard 1gram dose sometimes fails to eradicate the infection (treatment failure). One hypothesis proposed for treatment failure has been insufficient levels of the antibiotic at the site of infection. We developed an assay using liquid chromatography and tandem mass spectrometry (LC-MS/MS) to measure azithromycin concentration in high-vaginal swabs and monitor how concentration changes over time following routine azithromycin treatment. METHODS Azithromycin concentrations were measured in two groups of women either within the first 24h of taking a 1g dose (N = 11) or over 9 days (N = 10). Azithromycin concentrations were normalised to an internal standard (leucine enkephalin), and the bulk lipid species phosphatidylcholine [PC(34:1)], using an Agilent 6490 triple quadrupole instrument in positive ionisation mode. The abundances of azithromycin, PC(34:1), and leu-enkephalin were determined by multiple reaction monitoring and absolute levels of azithromycin estimated using standard curves prepared on vaginal specimens. RESULTS Vaginal azithromycin concentrations of women were rapidly obtained after 5h post-treatment (mean concentration = 1031mcg/mg of lipid, range = 173-2693mcg/mg). In women followed for 9 days, peak concentrations were highest after day 2 (mean concentration = 2206mcg/mg, range = 721-5791mcg/mg), and remained high for at least 9 days with a mean concentration of 384mcg/mg (range = 139-1024mcg/mg) on day 9. CONCLUSION Our study confirmed that a single 1g dose of azithromycin is rapidly absorbed and remains in the vagina at relatively high levels for at least a week, suggesting that poor antibiotic absorption is unlikely to be an explanation for treatment failure.
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Affiliation(s)
- Lenka A. Vodstrcil
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Australia
- Murdoch Children’s Research Institute, Parkville, Australia
- Central Clinical School, Monash University, Melbourne Sexual Health Centre, Carlton, Australia
| | | | - Fabian Y. S. Kong
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Australia
| | - Dedreia Tull
- Metabolomics Australia, Bio21 Institute, University of Melbourne, Parkville, Australia
| | - Karen Worthington
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Australia
- Central Clinical School, Monash University, Melbourne Sexual Health Centre, Carlton, Australia
| | - Marcus Y. Chen
- Central Clinical School, Monash University, Melbourne Sexual Health Centre, Carlton, Australia
| | | | - Peter Timms
- University of the Sunshine Coast, Maroochydore, Australia
| | - Malcolm J. McConville
- Metabolomics Australia, Bio21 Institute, University of Melbourne, Parkville, Australia
| | - Christopher K. Fairley
- Central Clinical School, Monash University, Melbourne Sexual Health Centre, Carlton, Australia
| | - Catriona S. Bradshaw
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Australia
- Central Clinical School, Monash University, Melbourne Sexual Health Centre, Carlton, Australia
| | - Sepehr N. Tabrizi
- Murdoch Children’s Research Institute, Parkville, Australia
- Department of Microbiology and Infectious Diseases, The Royal Women’s Hospital, Parkville, Victoria, Australia
- Department of Obstetrics and Gynecology, University of Melbourne, The Royal Women’s Hospital Parkville, Victoria, Australia
| | - Jane S. Hocking
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Australia
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208
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Leonard CA, Schoborg RV, Borel N. Productive and Penicillin-Stressed Chlamydia pecorum Infection Induces Nuclear Factor Kappa B Activation and Interleukin-6 Secretion In Vitro. Front Cell Infect Microbiol 2017; 7:180. [PMID: 28553623 PMCID: PMC5425588 DOI: 10.3389/fcimb.2017.00180] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 04/25/2017] [Indexed: 11/13/2022] Open
Abstract
Nuclear factor kappa B (NFκB) is an inflammatory transcription factor that plays an important role in the host immune response to infection. The potential for chlamydiae to activate NFκB has been an area of interest, however most work has focused on chlamydiae impacting human health. Given that inflammation characteristic of chlamydial infection may be associated with severe disease outcomes or contribute to poor overall fitness in farmed animals, we evaluated the ability of porcine chlamydiae to induce NFκB activation in vitro. C. pecorum infection induced both NFκB nuclear translocation and activation at 2 hours post infection (hpi), an effect strongly enhanced by suppression of host de novo protein synthesis. C. suis and C. trachomatis showed less capacity for NFκB activation compared to C. pecorum, suggesting a species-specific variation in NFκB activation. At 24 hpi, C. pecorum induced significant NFκB activation, an effect not abolished by penicillin (beta lactam)-induced chlamydial stress. C. pecorum-dependent secretion of interleukin 6 was also detected in the culture supernatant of infected cells at 24 hpi, and this effect, too, was unchanged by penicillin-induced chlamydial stress. Taken together, these results suggest that NFκB participates in the early inflammatory response to C. pecorum and that stressed chlamydiae can promote inflammation.
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Affiliation(s)
- Cory A Leonard
- Department of Pathobiology, Institute of Veterinary Pathology, University of ZurichZurich, Switzerland
| | - Robert V Schoborg
- Department of Biomedical Sciences, Center for Inflammation, Infectious Disease and Immunity, James H. Quillen College of Medicine, East Tennessee State UniversityJohnson City, TN, USA
| | - Nicole Borel
- Department of Pathobiology, Institute of Veterinary Pathology, University of ZurichZurich, Switzerland
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209
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Ran O, Liang M, Yu J, Yu M, Song Y, Yimou W. Recombinant protein CPSIT_0846 induces protective immunity against Chlamydia psittaci infection in BALB/c mice. Pathog Dis 2017; 75:2996645. [PMID: 28204474 DOI: 10.1093/femspd/ftx018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 02/12/2017] [Indexed: 11/14/2022] Open
Abstract
Chlamydia psittaci is an obligate intracellular bacteria that causes respiratory disease in poultry and humans. Currently, there are no licensed vaccines against chlamydial infection in humans. The transmembrane head protein CPSIT_0846 of C. psittaci is a putative member of the larger Inc protein family. In this study, we investigated immunogenicity and protective efficacy of the recombinant CPSIT_0846 protein in BALB/c mice. Mice immunized with CPSIT_0846 developed strong T-lymphocyte responses that were recalled by the immunogen CPSIT_0846 in an in vitro restimulation assay. These T cells displayed a strong Th1-biased cytokine profile with high levels of IFN-γ. At the same time, a strong humoral immune response was also detected in the immunized mice with high titers of Chlamydia psittaci-specific serum IgG antibodies. More importantly, the robust immune responses correlated well with significantly reduced chlamydial burden and inflammatory pathology in the mouse lungs upon an airway challenge infection. The above results together suggest that the CPSIT_0846 protein may be a potential vaccine candidate antigen for inducing protection against C. psittaci infection and disease in the airway.
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Affiliation(s)
- Ou Ran
- Pathogenic Biology Institute, Medical College, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hengyang 421001, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China.,Department of Clinical Laboratory, Central Hospital of Xiangtan, Xiangtan 411100, China
| | - Mingxing Liang
- Department of Clinical Laboratory, the First People's Hospital of Huaihua, Huaihua 418000, China
| | - Jian Yu
- Department of Experimental Zoology, Medical College, University of South China, Hengyang 421001, China
| | - Minjun Yu
- Pathogenic Biology Institute, Medical College, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hengyang 421001, China
| | - Ying Song
- Department of Pathology, University of South China, Hengyang 421001, China
| | - Wu Yimou
- Pathogenic Biology Institute, Medical College, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hengyang 421001, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
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210
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Chlamydia trachomatis Cellular Exit Alters Interactions with Host Dendritic Cells. Infect Immun 2017; 85:IAI.00046-17. [PMID: 28223346 DOI: 10.1128/iai.00046-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 02/10/2017] [Indexed: 12/23/2022] Open
Abstract
The strategies utilized by pathogens to exit host cells are an area of pathogenesis which has received surprisingly little attention, considering the necessity of this step for infections to propagate. Even less is known about how exit through these pathways affects downstream host-pathogen interactions and the generation of an immune response. Chlamydia trachomatis exits host epithelial cells through two equally active mechanisms: lysis and extrusion. Studies have characterized the outcome of interactions between host innate immune cells, such as dendritic cells and macrophages, and free, extracellular Chlamydia bacteria, such as those resulting from lysis. Exit via extrusion generates a distinct, host-membrane-bound compartment of Chlamydia separate from the original infected cell. In this study, we assessed the effect of containment within extrusions upon the interaction between Chlamydia and host dendritic cells. Extrusion dramatically affected the outcome of Chlamydia-dendritic cell interactions for both the bacterium and the host cell. Dendritic cells rapidly underwent apoptosis in response to engulfment of an extrusion, while uptake of an equivalent dose of free Chlamydia had no such effect. Containment within an extrusion also prolonged bacterial survival within dendritic cells and altered the initial innate immune signaling by the dendritic cell.
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211
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Cenci U, Bhattacharya D, Weber APM, Colleoni C, Subtil A, Ball SG. Biotic Host-Pathogen Interactions As Major Drivers of Plastid Endosymbiosis. TRENDS IN PLANT SCIENCE 2017; 22:316-328. [PMID: 28089380 DOI: 10.1016/j.tplants.2016.12.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 11/21/2016] [Accepted: 12/12/2016] [Indexed: 05/22/2023]
Abstract
The plastid originated 1.5 billion years ago through a primary endosymbiosis involving a heterotrophic eukaryote and an ancient cyanobacterium. Phylogenetic and biochemical evidence suggests that the incipient endosymbiont interacted with an obligate intracellular chlamydial pathogen that housed it in an inclusion. This aspect of the ménage-à-trois hypothesis (MATH) posits that Chlamydiales provided critical novel transporters and enzymes secreted by the pathogens in the host cytosol. This initiated the efflux of photosynthate to both the inclusion lumen and host cytosol. Here we review the experimental evidence supporting the MATH and focus on chlamydial genes that replaced existing cyanobacterial functions. The picture emerging from these studies underlines the importance of chlamydial host-pathogen interactions in the metabolic integration of the primary plastid.
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Affiliation(s)
- Ugo Cenci
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 CNRS-USTL, Cité Scientifique, 59655 Villeneuve d'Ascq Cedex, France
| | - Debashish Bhattacharya
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ 08540, USA
| | - Andreas P M Weber
- Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University, D-40225 Düsseldorf, Germany
| | - Christophe Colleoni
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 CNRS-USTL, Cité Scientifique, 59655 Villeneuve d'Ascq Cedex, France
| | - Agathe Subtil
- Institut Pasteur, Unité de Biologie Cellulaire de l'Infection Microbienne, 25 Rue du Dr Roux, 75015 Paris, France
| | - Steven G Ball
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 CNRS-USTL, Cité Scientifique, 59655 Villeneuve d'Ascq Cedex, France.
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212
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Chowdhury SR, Reimer A, Sharan M, Kozjak-Pavlovic V, Eulalio A, Prusty BK, Fraunholz M, Karunakaran K, Rudel T. Chlamydia preserves the mitochondrial network necessary for replication via microRNA-dependent inhibition of fission. J Cell Biol 2017; 216:1071-1089. [PMID: 28330939 PMCID: PMC5379946 DOI: 10.1083/jcb.201608063] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 12/09/2016] [Accepted: 02/15/2017] [Indexed: 11/22/2022] Open
Abstract
Chlamydiae are intracellular pathogens that depend on the host for their survival and development. Chowdhury et al. demonstrate that Chlamydia trachomatis infection can prevent mitochondrial fission in primary cells by reducing DRP1 abundance via miR-30c–dependent inhibition of p53. Obligate intracellular bacteria such as Chlamydia trachomatis depend on metabolites of the host cell and thus protect their sole replication niche by interfering with the host cells’ stress response. Here, we investigated the involvement of host microRNAs (miRNAs) in maintaining the viability of C. trachomatis–infected primary human cells. We identified miR-30c-5p as a prominently up-regulated miRNA required for the stable down-regulation of p53, a major suppressor of metabolite supply in C. trachomatis–infected cells. Loss of miR-30c-5p led to the up-regulation of Drp1, a mitochondrial fission regulator and a target gene of p53, which, in turn, severely affected chlamydial growth and had a marked effect on the mitochondrial network. Drp1-induced mitochondrial fragmentation prevented replication of C. trachomatis even in p53-deficient cells. Additionally, Chlamydia maintain mitochondrial integrity during reactive oxygen species–induced stress that occurs naturally during infection. We show that C. trachomatis require mitochondrial ATP for normal development and hence postulate that they preserve mitochondrial integrity through a miR-30c-5p–dependent inhibition of Drp1-mediated mitochondrial fission.
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Affiliation(s)
| | - Anastasija Reimer
- Department of Microbiology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Malvika Sharan
- Institute for Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Vera Kozjak-Pavlovic
- Department of Microbiology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Ana Eulalio
- Institute for Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Bhupesh K Prusty
- Department of Microbiology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Martin Fraunholz
- Department of Microbiology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Karthika Karunakaran
- Department of Microbiology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Thomas Rudel
- Department of Microbiology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
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Rucks EA, Olson MG, Jorgenson LM, Srinivasan RR, Ouellette SP. Development of a Proximity Labeling System to Map the Chlamydia trachomatis Inclusion Membrane. Front Cell Infect Microbiol 2017; 7:40. [PMID: 28261569 PMCID: PMC5309262 DOI: 10.3389/fcimb.2017.00040] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 02/03/2017] [Indexed: 11/13/2022] Open
Abstract
Chlamydia grows within a membrane-bound vacuole termed an inclusion. The cellular processes that support the biogenesis and integrity of this pathogen-specified parasitic organelle are not understood. Chlamydia secretes integral membrane proteins called Incs that insert into the chlamydial inclusion membrane (IM). Incs contain at least two hydrophobic transmembrane domains flanked by termini, which vary in size and are exposed to the host cytosol. In addition, Incs are temporally expressed during the chlamydial developmental cycle. Data examining Inc function are limited because of (i) the difficulty in working with hydrophobic proteins and (ii) the inherent fragility of the IM. We hypothesize that Incs function collaboratively to maintain the integrity of the chlamydial inclusion with small Incs organizing the IM and larger Incs interfacing with host cell machinery. To study this hypothesis, we have adapted a proximity-labeling strategy using APEX2, a mutant soybean ascorbate peroxidase that biotinylates interacting and proximal proteins within minutes in the presence of H2O2 and its exogenous substrate, biotin-phenol. We successfully expressed, from an inducible background, APEX2 alone, or fusion proteins of IncATM (TM = transmembrane domain only), IncA, and IncF with APEX2 in Chlamydia trachomatis serovar L2. IncF-APEX2, IncA TM -APEX2, and IncA-APEX2 localized to the IM whereas APEX2, lacking a secretion signal, remained associated with the bacteria. We determined the impact of overexpression on inclusion diameter, plasmid stability, and Golgi-derived sphingomyelin acquisition. While there was an overall impact of inducing construct expression, IncF-APEX2 overexpression most negatively impacted these measurements. Importantly, Inc-APEX2 expression in the presence of biotin-phenol resulted in biotinylation of the IM. These data suggest that Inc expression is regulated to control optimal IM biogenesis. We subsequently defined lysis conditions that solubilized known Incs and were compatible with pulldown conditions. Importantly, we have created powerful tools to allow direct examination of the dynamic composition of the IM, which will provide novel insights into key interactions that promote chlamydial growth and development within the inclusion.
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Affiliation(s)
- Elizabeth A Rucks
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| | - Macy G Olson
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| | - Lisa M Jorgenson
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| | - Rekha R Srinivasan
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| | - Scot P Ouellette
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
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214
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Novel Detection Strategy To Rapidly Evaluate the Efficacy of Antichlamydial Agents. Antimicrob Agents Chemother 2017; 61:AAC.02202-16. [PMID: 27855081 DOI: 10.1128/aac.02202-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 11/06/2016] [Indexed: 12/24/2022] Open
Abstract
Chlamydia trachomatis infections present a major heath burden worldwide. The conventional method used to detect C. trachomatis is laborious. In the present study, a novel strategy was utilized to evaluate the impact of antimicrobial agents on the growth of C. trachomatis and its expression of ompA promoter-driven green fluorescence protein (GFP). We demonstrate that this GFP reporter system gives a robust fluorescent display of C. trachomatis growth in human cervical epithelial cells and, further, that GFP production directly correlates to changes in ompA expression following sufficient exposure to antimicrobials. Validation with azithromycin, the first-line macrolide drug used for the treatment of C. trachomatis infection, highlights the advantages of this method over the traditional method because of its simplicity and versatility. The results indicate both that ompA is highly responsive to antimicrobials targeting the transcription and translation of C. trachomatis and that there is a correlation between changing GFP levels and C. trachomatis growth. This proof-of-concept study also reveals that the ompA-GFP system can be easily adapted to rapidly assess antimicrobial effectiveness in a high-throughput format.
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215
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Key CE, Fisher DJ. Use of Group II Intron Technology for Targeted Mutagenesis in Chlamydia trachomatis. Methods Mol Biol 2017; 1498:163-177. [PMID: 27709575 DOI: 10.1007/978-1-4939-6472-7_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Dissecting the contribution of genes to virulence in fulfillment of Molecular Koch's postulates is essential for developing prevention and treatment strategies for bacterial pathogens. This chapter will discuss the application of a targeted, intron-based insertional mutagenesis method for creating mutants in the obligate, intracellular bacterial pathogen Chlamydia trachomatis. The methods employed for intron targeting, mutant selection, and mutant verification will be outlined including available selection markers, gene targeting strategies, and potential pitfalls.
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Affiliation(s)
- Charlotte E Key
- Department of Microbiology, Southern Illinois University, 1125 Lincoln Drive, Carbondale, IL, 62901, USA
| | - Derek J Fisher
- Department of Microbiology, Southern Illinois University, 1125 Lincoln Drive, Carbondale, IL, 62901, USA.
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216
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Christensen S, Grøftehauge MK, Byriel K, Huston WM, Furlong E, Heras B, Martin JL, McMahon RM. Structural and Biochemical Characterization of Chlamydia trachomatis DsbA Reveals a Cysteine-Rich and Weakly Oxidising Oxidoreductase. PLoS One 2016; 11:e0168485. [PMID: 28030602 PMCID: PMC5193440 DOI: 10.1371/journal.pone.0168485] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 11/30/2016] [Indexed: 11/24/2022] Open
Abstract
The Gram negative bacteria Chlamydia trachomatis is an obligate intracellular human pathogen that can cause pelvic inflammatory disease, infertility and blinding trachoma. C. trachomatis encodes a homolog of the dithiol oxidoreductase DsbA. Bacterial DsbA proteins introduce disulfide bonds to folding proteins providing structural bracing for secreted virulence factors, consequently these proteins are potential targets for antimicrobial drugs. Despite sharing functional and structural characteristics, the DsbA enzymes studied to date vary widely in their redox character. In this study we show that the truncated soluble form of the predicted membrane anchored protein C. trachomatis DsbA (CtDsbA) has oxidase activity and redox properties broadly similar to other characterized DsbA proteins. However CtDsbA is distinguished from other DsbAs by having six cysteines, including a second disulfide bond, and an unusual dipeptide sequence in its catalytic motif (Cys-Ser-Ala-Cys). We report the 2.7 Å crystal structure of CtDsbA revealing a typical DsbA fold, which is most similar to that of DsbA-II type proteins. Consistent with this, the catalytic surface of CtDsbA is negatively charged and lacks the hydrophobic groove found in EcDsbA and DsbAs from other enterobacteriaceae. Biochemical characterization of CtDsbA reveals it to be weakly oxidizing compared to other DsbAs and with only a mildly destabilizing active site disulfide bond. Analysis of the crystal structure suggests that this redox character is consistent with a lack of contributing factors to stabilize the active site nucleophilic thiolate relative to more oxidizing DsbA proteins.
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Affiliation(s)
- Signe Christensen
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Morten K. Grøftehauge
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Karl Byriel
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Wilhelmina M. Huston
- School of Life Sciences, University of Technology Sydney, Broadway, New South Wales, Australia
| | - Emily Furlong
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Begoña Heras
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
| | - Jennifer L. Martin
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
- * E-mail: (JM); (RM)
| | - Róisín M. McMahon
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland, Australia
- * E-mail: (JM); (RM)
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217
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Claywell JE, Matschke LM, Fisher DJ. The Impact of Protein Phosphorylation on Chlamydial Physiology. Front Cell Infect Microbiol 2016; 6:197. [PMID: 28066729 PMCID: PMC5177608 DOI: 10.3389/fcimb.2016.00197] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/13/2016] [Indexed: 11/18/2022] Open
Abstract
Chlamydia are Gram negative bacterial pathogens responsible for disease in humans and economically important domesticated animals. As obligate intracellular bacteria, they must gain entry into a host cell where they propagate within a parasitophorous organelle that serves as an interactive interface between the bacterium and the host. Nutrient acquisition, growth, and evasion of host defense mechanisms occur from this location. In addition to these cellular and bacterial dynamics, Chlamydia differentiate between two morphologically distinct forms, the elementary body and reticulate body, that are optimized for either extracellular or intracellular survival, respectively. The mechanisms regulating and mediating these diverse physiological events remain largely unknown. Reversible phosphorylation, including classical two-component signaling systems, partner switching mechanisms, and the more recently appreciated bacterial Ser/Thr/Tyr kinases and phosphatases, has gained increasing attention for its role in regulating important physiological processes in bacteria including metabolism, development, and virulence. Phosphorylation modulates these events via rapid and reversible modification of protein substrates leading to changes in enzyme activity, protein oligomerization, cell signaling, and protein localization. The characterization of several conserved chlamydial protein kinases and phosphatases along with phosphoproteome analysis suggest that Chlamydia are capable of global and growth stage-specific protein phosphorylation. This mini review will highlight the current knowledge of protein phosphorylation in Chlamydia and its potential role in chlamydial physiology and, consequently, virulence. Comparisons with other minimal genome intracellular bacterial pathogens also will be addressed with the aim of illustrating the importance of this understudied regulatory mechanism on pathogenesis and the principle questions that remain unanswered.
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Affiliation(s)
- Ja E Claywell
- Department of Microbiology, Southern Illinois University Carbondale, IL, USA
| | - Lea M Matschke
- Department of Microbiology, Southern Illinois University Carbondale, IL, USA
| | - Derek J Fisher
- Department of Microbiology, Southern Illinois University Carbondale, IL, USA
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218
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Chlamydia trachomatis Is Resistant to Inclusion Ubiquitination and Associated Host Defense in Gamma Interferon-Primed Human Epithelial Cells. mBio 2016; 7:mBio.01417-16. [PMID: 27965446 PMCID: PMC5156299 DOI: 10.1128/mbio.01417-16] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The cytokine gamma interferon (IFN-γ) induces cell-autonomous immunity to combat infections with intracellular pathogens, such as the bacterium Chlamydia trachomatis. The present study demonstrates that IFN-γ-primed human cells ubiquitinate and eliminate intracellular Chlamydia-containing vacuoles, so-called inclusions. We previously described how IFN-γ-inducible immunity-related GTPases (IRGs) employ ubiquitin systems to mark inclusions for destruction in mouse cells and, furthermore, showed that the rodent pathogen Chlamydia muridarum blocks ubiquitination of its inclusions by interfering with mouse IRG function. Here, we report that ubiquitination of inclusions in human cells is independent of IRG and thus distinct from the murine pathway. We show that C. muridarum is susceptible to inclusion ubiquitination in human cells, while the closely related human pathogen C. trachomatis is resistant. C. muridarum, but not C. trachomatis, inclusions attract several markers of cell-autonomous immunity, including the ubiquitin-binding protein p62, the ubiquitin-like protein LC3, and guanylate-binding protein 1. Consequently, we find that IFN-γ priming of human epithelial cells triggers the elimination of C. muridarum, but not C. trachomatis, inclusions. This newly described defense pathway is independent of indole-2,3-dioxygenase, a known IFN-γ-inducible anti-Chlamydia resistance factor. Collectively, our observations indicate that C. trachomatis evolved mechanisms to avoid a human-specific, ubiquitin-mediated response as part of its unique adaptation to its human host. Chlamydia trachomatis is the leading cause of sexually transmitted bacterial infections and responsible for significant morbidity, including pelvic inflammatory disease, infertility, and ectopic pregnancies in women. As an obligate intracellular pathogen, C. trachomatis is in perpetual conflict with cell-intrinsic defense programs executed by its human host. Our study defines a novel anti-Chlamydia host resistance pathway active in human epithelial cells. This defense program promotes the deposition of the small antimicrobial protein ubiquitin on vacuoles containing Chlamydia. We show that this ubiquitin-based resistance pathway of human cells is highly effective against a Chlamydia species adapted to rodents but ineffective against human-adapted C. trachomatis. This observation indicates that C. trachomatis evolved strategies to avoid entrapment within ubiquitin-labeled vacuoles as part of its adaptation to the human innate immune system.
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219
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Rivas-Marín E, Canosa I, Devos DP. Evolutionary Cell Biology of Division Mode in the Bacterial Planctomycetes- Verrucomicrobia- Chlamydiae Superphylum. Front Microbiol 2016; 7:1964. [PMID: 28018303 PMCID: PMC5147048 DOI: 10.3389/fmicb.2016.01964] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 11/23/2016] [Indexed: 11/30/2022] Open
Abstract
Bacteria from the Planctomycetes, Verrucomicrobia, and Chlamydiae (PVC) superphylum are exceptions to the otherwise dominant mode of division by binary fission, which is based on the interaction between the FtsZ protein and the peptidoglycan (PG) biosynthesis machinery. Some PVC bacteria are deprived of the FtsZ protein and were also thought to lack PG. How these bacteria divide is still one of the major mysteries of microbiology. The presence of PG has recently been revealed in Planctomycetes and Chlamydiae, and proteins related to PG synthesis have been shown to be implicated in the division process in Chlamydiae, providing important insights into PVC mechanisms of division. Here, we review the historical lack of observation of PG in PVC bacteria, its recent detection in two phyla and its involvement in chlamydial cell division. Based on the detection of PG-related proteins in PVC proteomes, we consider the possible evolution of the diverse division mechanisms in these bacteria. We conclude by summarizing what is known and what remains to be understood about the evolutionary cell biology of PVC division modes.
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Affiliation(s)
- Elena Rivas-Marín
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas, Junta de Andalucía, Universidad Pablo de Olavide Seville, Spain
| | - Inés Canosa
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas, Junta de Andalucía, Universidad Pablo de Olavide Seville, Spain
| | - Damien P Devos
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas, Junta de Andalucía, Universidad Pablo de Olavide Seville, Spain
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220
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In vitro rescue of genital strains of Chlamydia trachomatis from interferon-γ and tryptophan depletion with indole-positive, but not indole-negative Prevotella spp. BMC Microbiol 2016; 16:286. [PMID: 27914477 PMCID: PMC5135834 DOI: 10.1186/s12866-016-0903-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/24/2016] [Indexed: 11/10/2022] Open
Abstract
Background The natural course of sexually transmitted infections caused by Chlamydia trachomatis varies between individuals. In addition to parasite and host effects, the vaginal microbiota might play a key role in the outcome of C. trachomatis infections. Interferon-gamma (IFN-γ), known for its anti-chlamydial properties, activates the expression of indoleamine 2,3-dioxygenase (IDO1) in epithelial cells, an enzyme that catabolizes the amino acid L- tryptophan into N-formylkynurenine, depleting the host cell’s pool of tryptophan. Although C. trachomatis is a tryptophan auxotroph, urogenital strains (but not ocular strains) have been shown in vitro to have the ability to produce tryptophan from indole using the tryptophan synthase (trpBA) gene. It has been suggested that indole producing bacteria from the vaginal microbiota could influence the outcome of Chlamydia infection. Results We used two in vitro models (treatment with IFN-γ or direct limitation of tryptophan), to study the effects of direct rescue by the addition of exogenous indole, or by the addition of culture supernatant from indole-positive versus indole-negative Prevotella strains, on the growth and infectivity of C. trachomatis. We found that only supernatants from the indole-positive strains, P. intermedia and P. nigrescens, were able to rescue tryptophan-starved C. trachomatis. In addition, we analyzed vaginal secretion samples to determine physiological indole concentrations. In spite of the complexity of vaginal secretions, we demonstrated that for some vaginal specimens with higher indole levels, there was a link to higher recovery of the Chlamydia under tryptophan-starved conditions, lending preliminary support to the critical role of the IFN-γ-tryptophan-indole axis in vivo. Conclusions Our data provide evidence for the ability of both exogenous indole as well as supernatant from indole producing bacteria such as Prevotella, to rescue genital C. trachomatis from tryptophan starvation. This adds weight to the hypothesis that the vaginal microbiota (particularly from women with lower levels of lactobacilli and higher levels of indole producing anaerobes) may be intrinsically linked to the outcome of chlamydial infections in some women. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0903-4) contains supplementary material, which is available to authorized users.
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221
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Vromman F, Perrinet S, Gehre L, Subtil A. The DUF582 Proteins of Chlamydia trachomatis Bind to Components of the ESCRT Machinery, Which Is Dispensable for Bacterial Growth In vitro. Front Cell Infect Microbiol 2016; 6:123. [PMID: 27774439 PMCID: PMC5053991 DOI: 10.3389/fcimb.2016.00123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 09/22/2016] [Indexed: 11/13/2022] Open
Abstract
Chlamydiae are Gram negative bacteria that develop exclusively inside eukaryotic host cells, within a membrane-bounded compartment. Members of the family Chlamydiaceae, such as Chlamydia trachomatis, are pathogenic species infecting vertebrates. They have a very reduced genome and exploit the capacities of their host for their own development, mainly through the secretion of proteins tailored to interfere with eukaryotic processes, called effector proteins. All Chlamydiaceae possess genes coding for four to five effectors that share a domain of unknown function (DUF582). Here we show that four of these effectors, which represent the conserved set in all Chlamydiaceae, accumulate in the infectious form of C. trachomatis, and are therefore likely involved in an early step of the developmental cycle. The fifth member of the family, CT621, is specific to C. trachomatis, and is secreted during the growth phase. Using a two-hybrid screen in yeast we identified an interaction between the host protein Hrs and the DUF582, which we confirmed by co-immunoprecipitations in co-transfected mammalian cells. Furthermore, we provide biochemical evidence that a second domain of one of the DUF582 proteins, CT619, binds the host protein Tsg101. Hrs and Tsg101 are both implicated in a well conserved machinery of the eukaryotic cell called the ESCRT machinery, which is involved in several cellular processes requiring membrane constriction. Using RNA interference targeting proteins implicated at different stages of ESCRT-driven processes, or inhibition by expression of a dominant negative mutant of VPS4, we demonstrated that this machinery was dispensable for bacterial entry, multiplication and differentiation into infectious progeny, and for uptake of glycogen into the parasitophorous vacuole. In light of these observations we discuss how the DUF582 proteins might target the ESCRT machinery during infection.
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Affiliation(s)
- François Vromman
- Institut Pasteur, Unité de Biologie Cellulaire de l'Infection MicrobienneParis, France; CNRS UMR 3691Paris, France; Université Pierre et Marie Curie, Cellule Pasteur UPMCParis, France
| | - Stéphanie Perrinet
- Institut Pasteur, Unité de Biologie Cellulaire de l'Infection MicrobienneParis, France; CNRS UMR 3691Paris, France
| | - Lena Gehre
- Institut Pasteur, Unité de Biologie Cellulaire de l'Infection MicrobienneParis, France; CNRS UMR 3691Paris, France
| | - Agathe Subtil
- Institut Pasteur, Unité de Biologie Cellulaire de l'Infection MicrobienneParis, France; CNRS UMR 3691Paris, France
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Sherchand SP, Ibana JA, Zea AH, Quayle AJ, Aiyar A. The High-Risk Human Papillomavirus E6 Oncogene Exacerbates the Negative Effect of Tryptophan Starvation on the Development of Chlamydia trachomatis. PLoS One 2016; 11:e0163174. [PMID: 27658027 PMCID: PMC5033384 DOI: 10.1371/journal.pone.0163174] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/02/2016] [Indexed: 12/26/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen that requires specific essential nutrients from the host cell, one of which is the amino acid tryptophan. In this context interferon gamma (IFNγ) is the major host protective cytokine against chlamydial infections because it induces the expression of the host enzyme, indoleamine 2,3-dioxygenase 1, that degrades tryptophan, thereby restricting bacterial replication. The mechanism by which IFNγ acts has been dissected in vitro using epithelial cell-lines such as HeLa, HEp-2, or the primary-like endocervical cell-line A2EN. All these cell-lines express the high-risk human papillomavirus oncogenes E6 & E7. While screening cell-lines to identify those suitable for C. trachomatis co-infections with other genital pathogens, we unexpectedly found that tryptophan starvation did not completely block chlamydial development in cell-lines that were HR-HPV negative, such as C33A and 293. Therefore, we tested the hypothesis that HR-HPV oncogenes modulate the effect of tryptophan starvation on chlamydial development by comparing chlamydial development in HeLa and C33A cell-lines that were both derived from cervical carcinomas. Our results indicate that during tryptophan depletion, unlike HeLa, C33A cells generate sufficient intracellular tryptophan via proteasomal activity to permit C. trachomatis replication. By generating stable derivatives of C33A that expressed HPV16 E6, E7 or E6 & E7, we found that E6 expression alone was sufficient to convert C33A cells to behave like HeLa during tryptophan starvation. The reduced tryptophan levels in HeLa cells have a biological consequence; akin to the previously described effect of IFNγ, tryptophan starvation protects C. trachomatis from clearance by doxycycline in HeLa but not C33A cells. Curiously, when compared to the known Homo sapiens proteome, the representation of tryptophan in the HR-HPV E6 & E6AP degradome is substantially lower, possibly providing a mechanism that underlies the lowered intracellular free tryptophan levels in E6-expressing cells during starvation.
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Affiliation(s)
- Shardulendra P. Sherchand
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana, 70112, United States of America
| | - Joyce A. Ibana
- Institute of Biology, University of the Philippines, Diliman, Quezon City, Philippines, PH, 1101
| | - Arnold H. Zea
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana, 70112, United States of America
| | - Alison J. Quayle
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana, 70112, United States of America
| | - Ashok Aiyar
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana, 70112, United States of America
- * E-mail:
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223
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Carter JD, Hudson AP. Recent advances and future directions in understanding and treating Chlamydia-induced reactive arthritis. Expert Rev Clin Immunol 2016; 13:197-206. [PMID: 27627462 DOI: 10.1080/1744666x.2017.1233816] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Reactive arthritis (ReA) is an inflammatory disease that can follow gastrointestinal or genitourinary infections. The primary etiologic agent for post-venereal ReA is the bacterium Chlamydia trachomatis; its relative, C pneumoniae, has also been implicated in disease induction although to a lesser degree. Studies have indicated that the arthritis is elicited by chlamydiae infecting synovial tissue in an unusual biologic state designated persistence. We review clinical aspects, host-pathogen interactions, and treatments for the disease. Areas covered: We briefly discuss both the historic and,more extensively, the current medical literature describing ReA, and we provide a discussion of the biology of the chlamydiae as it relates to elicitation of the disease. A summary of clinical aspects of Chlamydia-induced ReA is included to give context for approaches to treatment of the arthritis. Expert commentary: Basic research into the biology and host-pathogen interactions characteristic of C trachomatis has provided a wealth of information that underlies our current understanding of the pathogenic processes occurring in the ReA synovium. Importantly, a promising approach to cure of the disease is at hand. However, both basic and clinical research into Chlamydia-induced ReA has lagged over the last 5 years, including required studies relating to cure of the disease.
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Affiliation(s)
- John D Carter
- a Department of Internal Medicine, Division of Rheumatology , University of South Florida School of Medicine , Tampa , FL , USA
| | - Alan P Hudson
- b Department of Immunology and Microbiology , Wayne State University School of Medicine , Detroit , MI , USA
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Culture-independent genomic characterisation of Candidatus Chlamydia sanzinia, a novel uncultivated bacterium infecting snakes. BMC Genomics 2016; 17:710. [PMID: 27595750 PMCID: PMC5011893 DOI: 10.1186/s12864-016-3055-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/27/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recent molecular studies have revealed considerably more diversity in the phylum Chlamydiae than was previously thought. Evidence is growing that many of these novel chlamydiae may be important pathogens in humans and animals. A significant barrier to characterising these novel chlamydiae is the requirement for culturing. We recently identified a range of novel uncultured chlamydiae in captive snakes in Switzerland, however, nothing is known about their biology. Using a metagenomics approach, the aim of this study was to characterise the genome of a novel chlamydial taxon from the choana of a captive snake. In doing so, we propose a new candidate species in the genus Chlamydia (Candidatus Chlamydia sanzinia) and reveal new information about the biological diversity of this important group of pathogens. RESULTS We identified two chlamydial genomic contigs: a 1,113,073 bp contig, and a 7,504 bp contig, representing the chromosome and plasmid of Ca. Chlamydia sanzinia strain 2742-308, respectively. The 998 predicted coding regions include an expanded repertoire of outer membrane proteins (Pmps and Omps), some of which exhibited frameshift mutations, as well as several chlamydial virulence factors such as the translocating actin-recruitment phosphoprotein (Tarp) and macrophage inhibition potentiator (Mip). A suite of putative inclusion membrane proteins were also predicted. Notably, no evidence of a traditional chlamydial plasticity zone was identified. Phylogenetically, Ca. Chlamydia sanzinia forms a clade with C. pneumoniae and C. pecorum, distinct from former "Chlamydophila" species. CONCLUSIONS Genomic characterisation of a novel uncultured chlamydiae from the first reptilian host has expanded our understanding of the diversity and biology of a genus that was thought to be the most well-characterised in this unique phylum. It is anticipated that this method will be suitable for characterisation of other novel chlamydiae.
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Coinfection of Chlamydiae and other Bacteria in Reactive Arthritis and Spondyloarthritis: Need for Future Research. Microorganisms 2016; 4:microorganisms4030030. [PMID: 27681924 PMCID: PMC5039590 DOI: 10.3390/microorganisms4030030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/18/2016] [Accepted: 08/19/2016] [Indexed: 11/16/2022] Open
Abstract
Reactive (inflammatory) arthritis has been known for many years to follow genital infection with the intracellular bacterial pathogen Chlamydia trachomatis in some individuals. Recent studies from several groups have demonstrated that a related bacterium, the respiratory pathogen Chlamydia pneumoniae, can elicit a similar arthritis. Studies of these organisms, and of a set of gastrointestinal pathogens also associated with engendering inflammatory arthritis, have been relatively extensive. However, reports focusing on coinfections with these and/or other organisms, and the effects of such coinfections on the host immune and other systems, have been rare. In this article, we review the extant data regarding infections by multiple pathogens in the joint as they relate to engendering arthritis, and we suggest a number of research areas that must be given a high priority if we are to understand, and therefore to treat in an effective manner, such arthritides.
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226
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Tryptophan Codon-Dependent Transcription in Chlamydia pneumoniae during Gamma Interferon-Mediated Tryptophan Limitation. Infect Immun 2016; 84:2703-13. [PMID: 27400720 DOI: 10.1128/iai.00377-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/05/2016] [Indexed: 12/16/2022] Open
Abstract
In evolving to an obligate intracellular niche, Chlamydia has streamlined its genome by eliminating superfluous genes as it relies on the host cell for a variety of nutritional needs like amino acids. However, Chlamydia can experience amino acid starvation when the human host cell in which the bacteria reside is exposed to interferon gamma (IFN-γ), which leads to a tryptophan (Trp)-limiting environment via induction of the enzyme indoleamine-2,3-dioxygenase (IDO). The stringent response is used to respond to amino acid starvation in most bacteria but is missing from Chlamydia Thus, how Chlamydia, a Trp auxotroph, responds to Trp starvation in the absence of a stringent response is an intriguing question. We previously observed that C. pneumoniae responds to this stress by globally increasing transcription while globally decreasing translation, an unusual response. Here, we sought to understand this and hypothesized that the Trp codon content of a given gene would determine its transcription level. We quantified transcripts from C. pneumoniae genes that were either rich or poor in Trp codons and found that Trp codon-rich transcripts were increased, whereas those that lacked Trp codons were unchanged or even decreased. There were exceptions, and these involved operons or large genes with multiple Trp codons: downstream transcripts were less abundant after Trp codon-rich sequences. These data suggest that ribosome stalling on Trp codons causes a negative polar effect on downstream sequences. Finally, reassessing previous C. pneumoniae microarray data based on codon content, we found that upregulated transcripts were enriched in Trp codons, thus supporting our hypothesis.
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227
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Lawrence A, Fraser T, Gillett A, Tyndall JDA, Timms P, Polkinghorne A, Huston WM. Chlamydia Serine Protease Inhibitor, targeting HtrA, as a New Treatment for Koala Chlamydia infection. Sci Rep 2016; 6:31466. [PMID: 27530689 PMCID: PMC4987629 DOI: 10.1038/srep31466] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/20/2016] [Indexed: 01/01/2023] Open
Abstract
The koala, an iconic marsupial native to Australia, is a threatened species in many parts of the country. One major factor in the decline is disease caused by infection with Chlamydia. Current therapeutic strategies to treat chlamydiosis in the koala are limited. This study examines the effectiveness of an inhibitor, JO146, which targets the HtrA serine protease for treatment of C. pecorum and C. pneumoniae in vitro and ex vivo with the aim of developing a novel therapeutic for koala Chlamydia infections. Clinical isolates from koalas were examined for their susceptibility to JO146. In vitro studies demonstrated that treatment with JO146 during the mid-replicative phase of C. pecorum or C. pneumoniae infections resulted in a significant loss of infectious progeny. Ex vivo primary koala tissue cultures were used to demonstrate the efficacy of JO146 and the non-toxic nature of this compound on peripheral blood mononuclear cells and primary cell lines established from koala tissues collected at necropsy. Our results suggest that inhibition of the serine protease HtrA could be a novel treatment strategy for chlamydiosis in koalas.
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Affiliation(s)
- Amba Lawrence
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, 4059, Australia
| | - Tamieka Fraser
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydoore, QLD, 4558, Australia
| | - Amber Gillett
- Australia Zoo Wildlife Hospital, Beerwah, QLD, 4519, Australia
| | - Joel D A Tyndall
- New Zealand's National School of Pharmacy, University of Otago, Dunedin 9054 New Zealand
| | - Peter Timms
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydoore, QLD, 4558, Australia
| | - Adam Polkinghorne
- Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydoore, QLD, 4558, Australia
| | - Wilhelmina M Huston
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, 4059, Australia.,School of Life Sciences, University of Technology Sydney, Broadway, NSW, 2007, Australia
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228
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Abstract
Bacterial cell division predominantly occurs by a highly conserved process, termed binary fission, that requires the bacterial homologue of tubulin, FtsZ. Other mechanisms of bacterial cell division that are independent of FtsZ are rare. Although the obligate intracellular human pathogen Chlamydia trachomatis, the leading bacterial cause of sexually transmitted infections and trachoma, lacks FtsZ, it has been assumed to divide by binary fission. We show here that Chlamydia divides by a polarized cell division process similar to the budding process of a subset of the Planctomycetes that also lack FtsZ. Prior to cell division, the major outer-membrane protein of Chlamydia is restricted to one pole of the cell, and the nascent daughter cell emerges from this pole by an asymmetric expansion of the membrane. Components of the chlamydial cell division machinery accumulate at the site of polar growth prior to the initiation of asymmetric membrane expansion and inhibitors that disrupt the polarity of C. trachomatis prevent cell division. The polarized cell division of C. trachomatis is the result of the unipolar growth and FtsZ-independent fission of this coccoid organism. This mechanism of cell division has not been documented in other human bacterial pathogens suggesting the potential for developing Chlamydia-specific therapeutic treatments.
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229
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Sherchand S, Ibana JA, Quayle AJ, Aiyar A. Cell Intrinsic Factors Modulate the Effects of IFNγ on the Development of Chlamydia trachomatis. ACTA ACUST UNITED AC 2016; 7. [PMID: 27695641 DOI: 10.4172/2155-9597.1000282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chlamydia trachomatis is an obligate intracellular bacterial pathogen that cannot synthesize several amino acids, including tryptophan. Rather, C. trachomatis acquires these essential metabolites from its human host cell. Chlamydial dependence on host-provided tryptophan underlies a major host defense mechanism against the bacterium; namely, the induction of the host tryptophan-catabolizing enzyme, indoleamine 2,3- dioxygenase (IDO1) by interferon gamma (IFNγ), which leads to eradication of C. trachomatis by tryptophan starvation. For this reason, IFNγ is proposed to be the major host protective cytokine against genital C. trachomatis infections. The protective effect of IFNγ against C. trachomatis can be recapitulated in vitro using epithelial cell-lines such as the cervical carcinoma derived cell-line Hela, the Hela subclone HEp-2, and the cervical carcinoma derived cell-line ME180. Addition of IFNγ to these cells infected with C. trachomatis results in a strong bactericidal or bacteriostatic effect dependent on the concentration of IFNγ administered. Unlike Hela, HEp-2, and ME180, there are other human epithelial, or epithelial-like cell-lines where administration of IFNγ does not affect chlamydial replication, although they express the IFNγ receptor (IFNGR). In this report, we have characterized the mechanisms that underlie this dichotomy using the cell-lines C33A and 293. Akin to Hela, C33A is derived from a human cervical carcinoma, while 293 cells were produced by transfection of adenovirus type 5 DNA into embryonic kidney cells. We demonstrate that although IFNGR is expressed at high levels in C33A cells, its ligation by IFNγ does not result in STAT1 phosphorylation, an essential step for activation of the IDO1 promoter. Our results indicate that although the IFNγ-dependent signaling cascade is intact in 293 cells; the IDO1 promoter is not activated in these cells because it is epigenetically silenced, most likely by DNA methylation. Because polymorphisms in IFNγ, IFNGR, and the IDO1 promoter are known to affect other human infections or diseased states, our results indicate that the effect of allelic differences in these genes and the pathways they activate should be evaluated for their effect on C. trachomatis pathology.
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Affiliation(s)
- Shardulendra Sherchand
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, New Orleans, LA, USA
| | - Joyce A Ibana
- Institute of Biology, University of the Philippines, Diliman, Quezon City, Philippines, USA
| | - Alison J Quayle
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, New Orleans, LA, USA
| | - Ashok Aiyar
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, New Orleans, LA, USA
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230
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Beder T, Scheven MT, Praetzsch D, Westermann M, Saluz HP. Purification of infectious and non-infectious chlamydial particles using iodixanol for density gradient preparation. J Microbiol Methods 2016; 128:20-23. [PMID: 27378442 DOI: 10.1016/j.mimet.2016.06.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 11/28/2022]
Abstract
Chlamydiae are obligate intracellular bacteria with two distinct morphological stages, the infectious elementary bodies (EBs) and non-infectious reticulate bodies (RBs). Here we describe a rapid and straightforward protocol for the purification of EBs and RBs involving special density gradients. It has been successfully applied to three chlamydial species.
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Affiliation(s)
- Thomas Beder
- Department of Cell and Molecular Biology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany.
| | - Mareike Thea Scheven
- Department of Cell and Molecular Biology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany.
| | - Dominique Praetzsch
- Department of Cell and Molecular Biology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany.
| | - Martin Westermann
- Jena University Hospital, Electron Microscopy Center, Jena, Germany; Friedrich Schiller University Jena, Jena, Germany.
| | - Hans Peter Saluz
- Department of Cell and Molecular Biology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany; Friedrich Schiller University Jena, Jena, Germany.
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231
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Cenci U, Ducatez M, Kadouche D, Colleoni C, Ball SG. Was the Chlamydial Adaptative Strategy to Tryptophan Starvation an Early Determinant of Plastid Endosymbiosis? Front Cell Infect Microbiol 2016; 6:67. [PMID: 27446814 PMCID: PMC4916741 DOI: 10.3389/fcimb.2016.00067] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/07/2016] [Indexed: 12/17/2022] Open
Abstract
Chlamydiales were recently proposed to have sheltered the future cyanobacterial ancestor of plastids in a common inclusion. The intracellular pathogens are thought to have donated those critical transporters that triggered the efflux of photosynthetic carbon and the consequent onset of symbiosis. Chlamydiales are also suspected to have encoded glycogen metabolism TTS (Type Three Secretion) effectors responsible for photosynthetic carbon assimilation in the eukaryotic cytosol. We now review the reasons underlying other chlamydial lateral gene transfers evidenced in the descendants of plastid endosymbiosis. In particular we show that half of the genes encoding enzymes of tryptophan synthesis in Archaeplastida are of chlamydial origin. Tryptophan concentration is an essential cue triggering two alternative modes of replication in Chlamydiales. In addition, sophisticated tryptophan starvation mechanisms are known to act as antibacterial defenses in animal hosts. We propose that Chlamydiales have donated their tryptophan operon to the emerging plastid to ensure increased synthesis of tryptophan by the plastid ancestor. This would have allowed massive expression of the tryptophan rich chlamydial transporters responsible for symbiosis. It would also have allowed possible export of this valuable amino-acid in the inclusion of the tryptophan hungry pathogens. Free-living single cell cyanobacteria are devoid of proteins able to transport this amino-acid. We therefore investigated the phylogeny of the Tyr/Trp transporters homologous to E. coli TyrP/Mre and found yet another LGT from Chlamydiales to Archaeplastida thereby considerably strengthening our proposal.
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Affiliation(s)
- Ugo Cenci
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 Centre National de la Recherche Scientifique, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq France
| | - Mathieu Ducatez
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 Centre National de la Recherche Scientifique, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq France
| | - Derifa Kadouche
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 Centre National de la Recherche Scientifique, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq France
| | - Christophe Colleoni
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 Centre National de la Recherche Scientifique, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq France
| | - Steven G Ball
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 Centre National de la Recherche Scientifique, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq France
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232
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Chlamydia trachomatis Genital Tract Infections: When Host Immune Response and the Microbiome Collide. Trends Microbiol 2016; 24:750-765. [PMID: 27320172 DOI: 10.1016/j.tim.2016.05.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 05/06/2016] [Accepted: 05/25/2016] [Indexed: 02/08/2023]
Abstract
Genital infections with Chlamydia trachomatis continue to be a major health problem worldwide. While some individuals clear their infection (presumed to be the result of an effective Th1/interferon-γ response), others develop chronic infections and some are prone to repeat infections. In females in particular, chronic asymptomatic infections are common and can lead to pelvic inflammatory disease and infertility. Recent studies suggest that the genital tract microbiota could be a significant factor and explain person-to-person variation in C. trachomatis infections. One hypothesis suggests that C. trachomatis can use its trpBA genes to rescue tryptophan from indole, which is a product of anaerobic members of the genital tract microbiota. Women with particular microbiota types, such as seen in bacterial vaginosis, have increased numbers of anaerobes, and this would enable the chlamydia in these individuals to overcome the host's interferon-γ attempts to eliminate it, resulting in more repeat and/or chronic infections.
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233
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CTL0511 from Chlamydia trachomatis Is a Type 2C Protein Phosphatase with Broad Substrate Specificity. J Bacteriol 2016; 198:1827-1836. [PMID: 27114464 DOI: 10.1128/jb.00025-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/15/2016] [Indexed: 12/26/2022] Open
Abstract
UNLABELLED Protein phosphorylation has become increasingly recognized for its role in regulating bacterial physiology and virulence. Chlamydia spp. encode two validated Hanks'-type Ser/Thr protein kinases, which typically function with cognate protein phosphatases and appear capable of global protein phosphorylation. Consequently, we sought to identify a Ser/Thr protein phosphatase partner for the chlamydial kinases. CTL0511 from Chlamydia trachomatis L2 434/Bu, which has homologs in all sequenced Chlamydia spp., is a predicted type 2C Ser/Thr protein phosphatase (PP2C). Recombinant maltose-binding protein (MBP)-tagged CTL0511 (rCTL0511) hydrolyzed p-nitrophenyl phosphate (pNPP), a generic phosphatase substrate, in a MnCl2-dependent manner at physiological pH. Assays using phosphopeptide substrates revealed that rCTL0511 can dephosphorylate phosphorylated serine (P-Ser), P-Thr, and P-Tyr residues using either MnCl2 or MgCl2, indicating that metal usage can alter substrate preference. Phosphatase activity was unaffected by PP1, PP2A, and PP3 phosphatase inhibitors, while mutation of conserved PP2C residues significantly inhibited activity. Finally, phosphatase activity was detected in elementary body (EB) and reticulate body (RB) lysates, supporting a role for protein dephosphorylation in chlamydial development. These findings support that CTL0511 is a metal-dependent protein phosphatase with broad substrate specificity, substantiating a reversible phosphorylation network in C. trachomatis IMPORTANCE Chlamydia spp. are obligate intracellular bacterial pathogens responsible for a variety of diseases in humans and economically important animal species. Our work demonstrates that Chlamydia spp. produce a PP2C capable of dephosphorylating P-Thr, P-Ser, and P-Tyr and that Chlamydia trachomatis EBs and RBs possess phosphatase activity. In conjunction with the chlamydial Hanks'-type kinases Pkn1 and PknD, validation of CTL0511 fulfills the enzymatic requirements for a reversible phosphoprotein network. As protein phosphorylation regulates important cellular processes, including metabolism, differentiation, and virulence, in other bacterial pathogens, these results set the stage for elucidating the role of global protein phosphorylation in chlamydial physiology and virulence.
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234
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Cong Y, Gao L, Zhang Y, Xian Y, Hua Z, Elaasar H, Shen L. Quantifying promoter activity during the developmental cycle of Chlamydia trachomatis. Sci Rep 2016; 6:27244. [PMID: 27263495 PMCID: PMC4893696 DOI: 10.1038/srep27244] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/10/2016] [Indexed: 11/09/2022] Open
Abstract
Chlamydia trachomatis is an important human pathogen that undergoes a characteristic development cycle correlating with stage-specific gene expression profiles. Taking advantage of recent developments in the genetic transformation in C. trachomatis, we constructed a versatile green fluorescent protein (GFP) reporter system to study the development-dependent function of C. trachomatis promoters in an attempt to elucidate the mechanism that controls C. trachomatis adaptability. We validated the use of the GFP reporter system by visualizing the activity of an early euo gene promoter. Additionally, we uncovered a new ompA promoter, which we named P3, utilizing the GFP reporter system combined with 5' rapid amplification of cDNA ends (RACE), in vitro transcription assays, real-time quantitative RT-PCR (RT-qPCR), and flow cytometry. Mutagenesis of the P3 region verifies that P3 is a new class of C. trachomatis σ(66)-dependent promoter, which requires an extended -10 TGn motif for transcription. These results corroborate complex developmentally controlled ompA expression in C. trachomatis. The exploitation of genetically labeled C. trachomatis organisms with P3-driven GFP allows for the observation of changes in ompA expression in response to developmental signals. The results of this study could be used to complement previous findings and to advance understanding of C. trachomatis genetic expression.
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Affiliation(s)
- Yanguang Cong
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.,Department of Microbiology, Third Military Medical University, Chongqing, China, 400038
| | - Leiqiong Gao
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China, 400014
| | - Yan Zhang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China, 400014
| | - Yuqi Xian
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China, 400014
| | - Ziyu Hua
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China, 400014
| | - Hiba Elaasar
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Li Shen
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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235
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Waguia Kontchou C, Tzivelekidis T, Gentle IE, Häcker G. Infection of epithelial cells withChlamydia trachomatisinhibits TNF-induced apoptosis at the level of receptor internalization while leaving non-apoptotic TNF-signalling intact. Cell Microbiol 2016; 18:1583-1595. [DOI: 10.1111/cmi.12598] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Collins Waguia Kontchou
- Institute of Medical Microbiology and Hygiene; University Medical Centre Freiburg; Hermann-Herder-Str. 11 D-79104 Freiburg Germany
| | - Tina Tzivelekidis
- Institute of Medical Microbiology and Hygiene; University Medical Centre Freiburg; Hermann-Herder-Str. 11 D-79104 Freiburg Germany
| | - Ian E Gentle
- Institute of Medical Microbiology and Hygiene; University Medical Centre Freiburg; Hermann-Herder-Str. 11 D-79104 Freiburg Germany
| | - Georg Häcker
- Institute of Medical Microbiology and Hygiene; University Medical Centre Freiburg; Hermann-Herder-Str. 11 D-79104 Freiburg Germany
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236
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Tan GMY, Lim HJ, Yeow TC, Movahed E, Looi CY, Gupta R, Arulanandam BP, Abu Bakar S, Sabet NS, Chang LY, Wong WF. Temporal proteomic profiling of Chlamydia trachomatis-infected HeLa-229 human cervical epithelial cells. Proteomics 2016; 16:1347-60. [PMID: 27134121 DOI: 10.1002/pmic.201500219] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 02/15/2016] [Accepted: 03/01/2016] [Indexed: 12/30/2022]
Abstract
Chlamydia trachomatis is the leading causative agent of bacterial sexually transmitted infections worldwide which can lead to female pelvic inflammatory disease and infertility. A greater understanding of host response during chlamydial infection is essential to design intervention technique to reduce the increasing incidence rate of genital chlamydial infection. In this study, we investigated proteome changes in epithelial cells during C. trachomatis infection by using an isobaric tags for relative and absolute quantitation (iTRAQ) labeling technique coupled with a liquid chromatography-tandem mass spectrometry (LC-MS(3) ) analysis. C. trachomatis (serovar D, MOI 1)-infected HeLa-229 human cervical carcinoma epithelial cells (at 2, 4 and 8 h) showed profound modifications of proteome profile which involved 606 host proteins. MGST1, SUGP2 and ATXN10 were among the top in the list of the differentially upregulated protein. Through pathway analysis, we suggested the involvement of eukaryotic initiation factor 2 (eIF2) and mammalian target of rapamycin (mTOR) in host cells upon C. trachomatis infection. Network analysis underscored the participation of DNA repair mechanism during C. trachomatis infection. In summary, intense modifications of proteome profile in C. trachomatis-infected HeLa-229 cells indicate complex host-pathogen interactions at early phase of chlamydial infection.
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Affiliation(s)
- Grace Min Yi Tan
- Department of Medical Microbiology, Tropical Infectious Disease Research and Education Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Hui Jing Lim
- Department of Medical Microbiology, Tropical Infectious Disease Research and Education Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Tee Cian Yeow
- Department of Medical Microbiology, Tropical Infectious Disease Research and Education Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Elaheh Movahed
- Department of Medical Microbiology, Tropical Infectious Disease Research and Education Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chung Yeng Looi
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Rishein Gupta
- Center of Excellence in Infection Genomics, South Texas Center For Emerging Infectious Diseases, University of Texas at San Antonio, Texas, USA
| | - Bernard P Arulanandam
- Center of Excellence in Infection Genomics, South Texas Center For Emerging Infectious Diseases, University of Texas at San Antonio, Texas, USA
| | - Sazaly Abu Bakar
- Department of Medical Microbiology, Tropical Infectious Disease Research and Education Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | | | - Li-Yen Chang
- Department of Medical Microbiology, Tropical Infectious Disease Research and Education Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Won Fen Wong
- Department of Medical Microbiology, Tropical Infectious Disease Research and Education Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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237
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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.
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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.
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238
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A Functional Core of IncA Is Required for Chlamydia trachomatis Inclusion Fusion. J Bacteriol 2016; 198:1347-55. [PMID: 26883826 DOI: 10.1128/jb.00933-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/10/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Chlamydia trachomatis is an obligate intracellular pathogen that is the etiological agent of a variety of human diseases, including blinding trachoma and sexually transmitted infections. Chlamydiae replicate within a membrane-bound compartment, termed an inclusion, which they extensively modify by the insertion of type III secreted proteins called Inc proteins. IncA is an inclusion membrane protein that encodes two coiled-coil domains that are homologous to eukaryotic SNARE (soluble N-ethylmaleimide-sensitive factor attachment receptor) motifs. Recent biochemical evidence suggests that a functional core, composed of SNARE-like domain 1 (SLD-1) and part of SNARE-like domain 2 (SLD-2), is required for the characteristic homotypic fusion of C. trachomatis inclusions in multiply infected cells. To verify the importance of IncA in homotypic fusion in Chlamydia, we generated an incA::bla mutant. Insertional inactivation of incA resulted in the formation of nonfusogenic inclusions, a phenotype that was completely rescued by complementation with full-length IncA. Rescue of homotypic inclusion fusion was dependent on the presence of the functional core consisting of SLD-1 and part of SLD-2. Collectively, these results confirm in vitro membrane fusion assays identifying functional domains of IncA and expand the genetic tools available for identification of chlamydia with a method for complementation of site-specific mutants. IMPORTANCE Chlamydia trachomatis replicates within a parasitophorous vacuole termed an inclusion. The chlamydial inclusions are nonfusogenic with vesicles in the endocytic pathway but, in multiply infected cells, fuse with each other to form a single large inclusion. This homotypic fusion is dependent upon the presence of a chlamydial inclusion membrane-localized protein, IncA. Specificity of membrane fusion in eukaryotic cells is regulated by SNARE (soluble N-ethylmaleimide sensitive factor attachment receptor) proteins on the cytosolic face of vesicles and target membranes. IncA contains two SNARE-like domains. Newly developed genetic tools for the complementation of targeted mutants in C. trachomatis are used to confirm the minimal requirement of SNARE-like motifs necessary to promote the homotypic fusion of inclusions.
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239
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Viana F, Buchrieser C. Environmental treasures: co-isolation of the first marine Chlamydiae and its protozoan host. Environ Microbiol 2016; 18:2295-7. [PMID: 26996407 DOI: 10.1111/1462-2920.13264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 02/12/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Flávia Viana
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France.,CNRS UMR 3525, 75724, Paris, France
| | - Carmen Buchrieser
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France.,CNRS UMR 3525, 75724, Paris, France
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240
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Gehre L, Gorgette O, Perrinet S, Prevost MC, Ducatez M, Giebel AM, Nelson DE, Ball SG, Subtil A. Sequestration of host metabolism by an intracellular pathogen. eLife 2016; 5:e12552. [PMID: 26981769 PMCID: PMC4829429 DOI: 10.7554/elife.12552] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 03/15/2016] [Indexed: 01/22/2023] Open
Abstract
For intracellular pathogens, residence in a vacuole provides a shelter against cytosolic host defense to the cost of limited access to nutrients. The human pathogen Chlamydia trachomatis grows in a glycogen-rich vacuole. How this large polymer accumulates there is unknown. We reveal that host glycogen stores shift to the vacuole through two pathways: bulk uptake from the cytoplasmic pool, and de novo synthesis. We provide evidence that bacterial glycogen metabolism enzymes are secreted into the vacuole lumen through type 3 secretion. Our data bring strong support to the following scenario: bacteria co-opt the host transporter SLC35D2 to import UDP-glucose into the vacuole, where it serves as substrate for de novo glycogen synthesis, through a remarkable adaptation of the bacterial glycogen synthase. Based on these findings we propose that parasitophorous vacuoles not only offer protection but also provide a microorganism-controlled metabolically active compartment essential for redirecting host resources to the pathogens.
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Affiliation(s)
- Lena Gehre
- Unité de Biologie cellulaire de l'infection microbienne, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
| | - Olivier Gorgette
- Plate-forme de Microscopie Ultrastructurale, Imagopole, Institut Pasteur, Paris, France
| | - Stéphanie Perrinet
- Unité de Biologie cellulaire de l'infection microbienne, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
| | | | - Mathieu Ducatez
- Unité de Glycobiologie Structurale et Fonctionnelle - CNRS UMR8576, Université de Lille, Lille, France
| | - Amanda M Giebel
- Department of Biology, Indiana University Bloomington, Bloomington, United States
| | - David E Nelson
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, United States
| | - Steven G Ball
- Unité de Glycobiologie Structurale et Fonctionnelle - CNRS UMR8576, Université de Lille, Lille, France
| | - Agathe Subtil
- Unité de Biologie cellulaire de l'infection microbienne, Institut Pasteur, Paris, France.,CNRS UMR3691, Paris, France
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241
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Hai J, Serradji N, Mouton L, Redeker V, Cornu D, El Hage Chahine JM, Verbeke P, Hémadi M. Targeted Delivery of Amoxicillin to C. trachomatis by the Transferrin Iron Acquisition Pathway. PLoS One 2016; 11:e0150031. [PMID: 26919720 PMCID: PMC4768884 DOI: 10.1371/journal.pone.0150031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 02/08/2016] [Indexed: 01/13/2023] Open
Abstract
Weak intracellular penetration of antibiotics makes some infections difficult to treat. The Trojan horse strategy for targeted drug delivery is among the interesting routes being explored to overcome this therapeutic difficulty. Chlamydia trachomatis, as an obligate intracellular human pathogen, is responsible for both trachoma and sexually transmitted diseases. Chlamydia develops in a vacuole and is therefore protected by four membranes (plasma membrane, bacterial inclusion membrane, and bacterial membranes). In this work, the iron-transport protein, human serum-transferrin, was used as a Trojan horse for antibiotic delivery into the bacterial vacuole. Amoxicillin was grafted onto transferrin. The transferrin-amoxicillin construct was characterized by mass spectrometry and absorption spectroscopy. Its affinity for transferrin receptor 1, determined by fluorescence emission titration [KaffTf-amox = (1.3 ± 1.0) x 108], is very close to that of transferrin [4.3 x 108]. Transmission electron and confocal microscopies showed a co-localization of transferrin with the bacteria in the vacuole and were also used to evaluate the antibiotic capability of the construct. It is significantly more effective than amoxicillin alone. These promising results demonstrate targeted delivery of amoxicillin to suppress Chlamydia and are of interest for Chlamydiaceae and maybe other intracellular bacteria therapies.
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Affiliation(s)
- Jun Hai
- ITODYS, Interfaces, Traitements, Organisation et Dynamique des Systèmes, Université Paris Diderot, Sorbonne Paris Cité, CNRS-UMR 7086, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
| | - Nawal Serradji
- ITODYS, Interfaces, Traitements, Organisation et Dynamique des Systèmes, Université Paris Diderot, Sorbonne Paris Cité, CNRS-UMR 7086, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
| | - Ludovic Mouton
- ITODYS, Interfaces, Traitements, Organisation et Dynamique des Systèmes, Université Paris Diderot, Sorbonne Paris Cité, CNRS-UMR 7086, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
| | - Virginie Redeker
- Paris-Saclay Institute of Neuroscience, CNRS-UMR 9197, 1 avenue de la Terrasse, 91190 Gif-sur-Yvette, France
| | - David Cornu
- Service d’Identification et de Caractérisation des Protéines, CNRS-UMR 9198, 1 avenue de la Terrasse, 91190 Gif-sur-Yvette, France
| | - Jean-Michel El Hage Chahine
- ITODYS, Interfaces, Traitements, Organisation et Dynamique des Systèmes, Université Paris Diderot, Sorbonne Paris Cité, CNRS-UMR 7086, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
- * E-mail: (MH); (JEHC); (PV)
| | - Philippe Verbeke
- UMR 1149 Inserm, Université Paris Diderot, Sorbonne Paris Cité, ERL-CNRS 8252, Faculté de Médecine, site Bichat, 16 rue Henri Huchard, 75018 Paris, France
- * E-mail: (MH); (JEHC); (PV)
| | - Miryana Hémadi
- ITODYS, Interfaces, Traitements, Organisation et Dynamique des Systèmes, Université Paris Diderot, Sorbonne Paris Cité, CNRS-UMR 7086, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
- * E-mail: (MH); (JEHC); (PV)
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242
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Smith-Norowitz TA, Chotikanatis K, Erstein DP, Perlman J, Norowitz YM, Joks R, Durkin HG, Hammerschlag MR, Kohlhoff S. Chlamydia pneumoniae enhances the Th2 profile of stimulated peripheral blood mononuclear cells from asthmatic patients. Hum Immunol 2016; 77:382-8. [PMID: 26924667 DOI: 10.1016/j.humimm.2016.02.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 02/23/2016] [Accepted: 02/24/2016] [Indexed: 01/31/2023]
Abstract
Chlamydia pneumoniae is a cause of respiratory infection in adults and children. There is evidence for an association between atypical bacterial respiratory pathogens and the pathogenesis of asthma. We compared T helper (Th) responses in C. pneumoniae - infected peripheral blood mononuclear cells (PBMC) in patients with or without asthma. PBMC (1×10(6)/mL) from asthmatic patients (N=11) and non-asthmatic controls (N=12) were infected or mock-infected for 1h +/- C. pneumoniae TW-183 at a multiplicity of infection (MOI)=1 and MOI=0.1, or cultured for 24h +/- Lactobacillus rhamnosus GG (LGG). Interleukin (IL)-4, IL-10, IL-12, Interferon (IFN)-gamma and total IgE levels were measured in supernatants (ELISA). C. pneumoniae infection led to an increase (>50%) of IgE levels in PBMC from asthmatics, compared with mock-infected on day 10; IgE wasn't detected in non-asthmatics. C. pneumoniae - infected PBMC from asthmatics increased levels of IL-4 and IFN-gamma after 24h, compared with PBMC alone; levels of IL-10 and IL-12 were low. When uninfected-PBMC from asthmatics were LGG-stimulated, after 24h, IL-4 was undetectable, but IL-10, IL-12, and IFN-gamma increased, compared with PBMC alone. Thus, C. pneumoniae infection has the ability to induce allergic responses in PBMC of asthmatics, as evidenced by production of Th2 responses and IgE.
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Affiliation(s)
- Tamar A Smith-Norowitz
- Department of Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States; Center for Allergy and Asthma Research, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States.
| | - Kobkul Chotikanatis
- Department of Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States
| | - David P Erstein
- Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States
| | - Jason Perlman
- Department of Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States
| | - Yitzchok M Norowitz
- Department of Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States
| | - Rauno Joks
- Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States; Center for Allergy and Asthma Research, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States
| | - Helen G Durkin
- Department of Pathology, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States; Center for Allergy and Asthma Research, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States
| | - Margaret R Hammerschlag
- Department of Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States
| | - Stephan Kohlhoff
- Department of Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States; Center for Allergy and Asthma Research, State University of New York Downstate Medical Center, Brooklyn, NY 11203, United States
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243
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Sandoz KM, Popham DL, Beare PA, Sturdevant DE, Hansen B, Nair V, Heinzen RA. Transcriptional Profiling of Coxiella burnetii Reveals Extensive Cell Wall Remodeling in the Small Cell Variant Developmental Form. PLoS One 2016; 11:e0149957. [PMID: 26909555 PMCID: PMC4766238 DOI: 10.1371/journal.pone.0149957] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/05/2016] [Indexed: 11/19/2022] Open
Abstract
A hallmark of Coxiella burnetii, the bacterial cause of human Q fever, is a biphasic developmental cycle that generates biologically, ultrastructurally, and compositionally distinct large cell variant (LCV) and small cell variant (SCV) forms. LCVs are replicating, exponential phase forms while SCVs are non-replicating, stationary phase forms. The SCV has several properties, such as a condensed nucleoid and an unusual cell envelope, suspected of conferring enhanced environmental stability. To identify genetic determinants of the LCV to SCV transition, we profiled the C. burnetii transcriptome at 3 (early LCV), 5 (late LCV), 7 (intermediate forms), 14 (early SCV), and 21 days (late SCV) post-infection of Vero epithelial cells. Relative to early LCV, genes downregulated in the SCV were primarily involved in intermediary metabolism. Upregulated SCV genes included those involved in oxidative stress responses, arginine acquisition, and cell wall remodeling. A striking transcriptional signature of the SCV was induction (>7-fold) of five genes encoding predicted L,D transpeptidases that catalyze nonclassical 3-3 peptide cross-links in peptidoglycan (PG), a modification that can influence several biological traits in bacteria. Accordingly, of cross-links identified, muropeptide analysis showed PG of SCV with 46% 3-3 cross-links as opposed to 16% 3-3 cross-links for LCV. Moreover, electron microscopy revealed SCV with an unusually dense cell wall/outer membrane complex as compared to LCV with its clearly distinguishable periplasm and inner and outer membranes. Collectively, these results indicate the SCV produces a unique transcriptome with a major component directed towards remodeling a PG layer that likely contributes to Coxiella's environmental resistance.
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Affiliation(s)
- Kelsi M. Sandoz
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - David L. Popham
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Paul A. Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Daniel E. Sturdevant
- Genomics Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Bryan Hansen
- Electron Microscopy Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Vinod Nair
- Electron Microscopy Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Robert A. Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
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244
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Good JAD, Silver J, Núñez-Otero C, Bahnan W, Krishnan KS, Salin O, Engström P, Svensson R, Artursson P, Gylfe Å, Bergström S, Almqvist F. Thiazolino 2-Pyridone Amide Inhibitors of Chlamydia trachomatis Infectivity. J Med Chem 2016; 59:2094-108. [PMID: 26849778 DOI: 10.1021/acs.jmedchem.5b01759] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The bacterial pathogen Chlamydia trachomatis is a global health burden currently treated with broad-spectrum antibiotics which disrupt commensal bacteria. We recently identified a compound through phenotypic screening that blocked infectivity of this intracellular pathogen without host cell toxicity (compound 1, KSK 120). Herein, we present the optimization of 1 to a class of thiazolino 2-pyridone amides that are highly efficacious (EC50 ≤ 100 nM) in attenuating infectivity across multiple serovars of C. trachomatis without host cell toxicity. The lead compound 21a exhibits reduced lipophilicity versus 1 and did not affect the growth or viability of representative commensal flora at 50 μM. In microscopy studies, a highly active fluorescent analogue 37 localized inside the parasitiphorous inclusion, indicative of a specific targeting of bacterial components. In summary, we present a class of small molecules to enable the development of specific treatments for C. trachomatis.
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Affiliation(s)
- James A D Good
- Department of Chemistry, Umeå University , 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden
| | - Jim Silver
- Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden.,Department of Molecular Biology, Umeå University , 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , 901 87 Umeå, Sweden
| | - Carlos Núñez-Otero
- Department of Clinical Microbiology, Umeå University , 901 85 Umeå, Sweden
| | - Wael Bahnan
- Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden.,Department of Molecular Biology, Umeå University , 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , 901 87 Umeå, Sweden
| | - K Syam Krishnan
- Department of Chemistry, Umeå University , 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden
| | - Olli Salin
- Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , 901 87 Umeå, Sweden.,Department of Clinical Microbiology, Umeå University , 901 85 Umeå, Sweden
| | - Patrik Engström
- Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden.,Department of Molecular Biology, Umeå University , 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , 901 87 Umeå, Sweden
| | - Richard Svensson
- Department of Pharmacy, Uppsala University , SE-751 23 Uppsala, Sweden.,The Uppsala University Drug Optimization and Pharmaceutical Profiling Platform, Chemical Biology Consortium Sweden, Uppsala University , SE-751 23 Uppsala, Sweden
| | - Per Artursson
- Department of Pharmacy, Uppsala University , SE-751 23 Uppsala, Sweden.,The Uppsala University Drug Optimization and Pharmaceutical Profiling Platform, Chemical Biology Consortium Sweden, Uppsala University , SE-751 23 Uppsala, Sweden
| | - Åsa Gylfe
- Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , 901 87 Umeå, Sweden.,Department of Clinical Microbiology, Umeå University , 901 85 Umeå, Sweden
| | - Sven Bergström
- Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden.,Department of Molecular Biology, Umeå University , 901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University , 901 87 Umeå, Sweden
| | - Fredrik Almqvist
- Department of Chemistry, Umeå University , 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research, Umeå University , 901 87 Umeå, Sweden
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245
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Fechtner T, Galle JN, Hegemann JH. The novel chlamydial adhesin CPn0473 mediates the lipid raft-dependent uptake of Chlamydia pneumoniae. Cell Microbiol 2016; 18:1094-105. [PMID: 26780295 PMCID: PMC5067637 DOI: 10.1111/cmi.12569] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 12/21/2015] [Accepted: 01/04/2016] [Indexed: 01/23/2023]
Abstract
Chlamydiae are Gram‐negative, obligate intracellular pathogens that pose a serious threat to public health worldwide. Chlamydial surface molecules are essential for host cell invasion. The first interaction with the host cell is thereby accomplished by the Outer membrane complex protein B (OmcB) binding to heparan sulfate moieties on the host cell surface, followed by the interaction of the chlamydial polymorphic membrane proteins (Pmps) with host cell receptors. Specifically, the interaction of the Pmp21 adhesin and invasin with its human interaction partner, the epidermal growth factor receptor, results in receptor activation, down‐stream signalling and finally internalization of the bacteria. Blocking both, the OmcB and Pmp21 adhesion pathways, did not completely abolish infection, suggesting the presence of additional factors relevant for host cell invasion. Here, we show that the novel surface protein CPn0473 of Chlamydia pneumoniae contributes to the binding and invasion of infectious chlamydial particles. CPn0473 is expressed late in the infection cycle and located on the infectious chlamydial cell surface. Soluble recombinant CPn0473 as well as rCPn0473‐coupled fluorescent latex beads adhere to human epithelial HEp‐2 cells. Interestingly, in classical infection blocking experiments pretreatment of HEp‐2 cells with rCPn0473 does not attenuate adhesion but promotes dose‐dependently internalization by C. pneumoniae suggesting an unusual mode of action for this adhesin. This CPn0473‐dependent promotion of infection by C. pneumoniae depends on two different domains within the protein and requires intact lipid rafts. Thus, inhibition of the interaction of CPn0473 with the host cell could provide a way to reduce the virulence of C. pneumoniae.
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Affiliation(s)
- Tim Fechtner
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Jan N Galle
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Johannes H Hegemann
- Lehrstuhl für Funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
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246
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Penicillin G-Induced Chlamydial Stress Response in a Porcine Strain of Chlamydia pecorum. Int J Microbiol 2016; 2016:3832917. [PMID: 26997956 PMCID: PMC4779511 DOI: 10.1155/2016/3832917] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/26/2016] [Indexed: 01/14/2023] Open
Abstract
Chlamydia pecorum causes asymptomatic infection and pathology in ruminants, pigs, and koalas. We characterized the antichlamydial effect of the beta lactam penicillin G on Chlamydia pecorum strain 1710S (porcine abortion isolate). Penicillin-exposed and mock-exposed infected host cells showed equivalent inclusions numbers. Penicillin-exposed inclusions contained aberrant bacterial forms and exhibited reduced infectivity, while mock-exposed inclusions contained normal bacterial forms and exhibited robust infectivity. Infectious bacteria production increased upon discontinuation of penicillin exposure, compared to continued exposure. Chlamydia-induced cell death occurred in mock-exposed controls; cell survival was improved in penicillin-exposed infected groups. Similar results were obtained both in the presence and in the absence of the eukaryotic protein translation inhibitor cycloheximide and at different times of initiation of penicillin exposure. These data demonstrate that penicillin G induces the chlamydial stress response (persistence) and is not bactericidal, for this chlamydial species/strain in vitro, regardless of host cell de novo protein synthesis.
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247
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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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Staying in Shape: the Impact of Cell Shape on Bacterial Survival in Diverse Environments. Microbiol Mol Biol Rev 2016; 80:187-203. [PMID: 26864431 DOI: 10.1128/mmbr.00031-15] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria display an abundance of cellular forms and can change shape during their life cycle. Many plausible models regarding the functional significance of cell morphology have emerged. A greater understanding of the genetic programs underpinning morphological variation in diverse bacterial groups, combined with assays of bacteria under conditions that mimic their varied natural environments, from flowing freshwater streams to diverse human body sites, provides new opportunities to probe the functional significance of cell shape. Here we explore shape diversity among bacteria, at the levels of cell geometry, size, and surface appendages (both placement and number), as it relates to survival in diverse environments. Cell shape in most bacteria is determined by the cell wall. A major challenge in this field has been deconvoluting the effects of differences in the chemical properties of the cell wall and the resulting cell shape perturbations on observed fitness changes. Still, such studies have begun to reveal the selective pressures that drive the diverse forms (or cell wall compositions) observed in mammalian pathogens and bacteria more generally, including efficient adherence to biotic and abiotic surfaces, survival under low-nutrient or stressful conditions, evasion of mammalian complement deposition, efficient dispersal through mucous barriers and tissues, and efficient nutrient acquisition.
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Buckner LR, Amedee AM, Albritton HL, Kozlowski PA, Lacour N, McGowin CL, Schust DJ, Quayle AJ. Chlamydia trachomatis Infection of Endocervical Epithelial Cells Enhances Early HIV Transmission Events. PLoS One 2016; 11:e0146663. [PMID: 26730599 PMCID: PMC4701475 DOI: 10.1371/journal.pone.0146663] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 12/21/2015] [Indexed: 01/20/2023] Open
Abstract
Chlamydia trachomatis causes a predominantly asymptomatic, but generally inflammatory, genital infection that is associated with an increased risk for HIV acquisition. Endocervical epithelial cells provide the major niche for this obligate intracellular bacterium in women, and the endocervix is also a tissue in which HIV transmission can occur. The mechanism by which CT infection enhances HIV susceptibility at this site, however, is not well understood. Utilizing the A2EN immortalized endocervical epithelial cell line grown on cell culture inserts, we evaluated the direct role that CT-infected epithelial cells play in facilitating HIV transmission events. We determined that CT infection significantly enhanced the apical-to-basolateral migration of cell-associated, but not cell-free, HIVBaL, a CCR5-tropic strain of virus, across the endocervical epithelial barrier. We also established that basolateral supernatants from CT-infected A2EN cells significantly enhanced HIV replication in peripheral mononuclear cells and a CCR5+ T cell line. These results suggest that CT infection of endocervical epithelial cells could facilitate both HIV crossing the mucosal barrier and subsequent infection or replication in underlying target cells. Our studies provide a mechanism by which this common STI could potentially promote the establishment of founder virus populations and the maintenance of local HIV reservoirs in the endocervix. Development of an HIV/STI co-infection model also provides a tool to further explore the role of other sexually transmitted infections in enhancing HIV acquisition.
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Affiliation(s)
- Lyndsey R. Buckner
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States of America
| | - Angela M. Amedee
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States of America
| | - Hannah L. Albritton
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States of America
| | - Pamela A. Kozlowski
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States of America
| | - Nedra Lacour
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States of America
| | - Chris L. McGowin
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States of America
- Department of Medicine, Section of Infectious Diseases, Louisiana State University Health Sciences Center, New Orleans, Louisiana, 70112, United States of America
| | - Danny J. Schust
- Department of Obstetrics, Gynecology and Women’s Health, University of Missouri, Columbia, MO 65201, United States of America
| | - Alison J. Quayle
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, United States of America
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Abstract
The lifestyle of Chlamydiae is unique: the bacteria alternate between two morphologically distinct forms, an infectious non-replicative elementary body (EB), and a replicative, non-infectious reticulate body (RB). This review focuses on recent advances in understanding the structure and function of the infectious form of the best-studied member of the phylum, the human pathogen Chlamydia trachomatis. Once considered as an inert particle of little functional capacity, the EB is now perceived as a sophisticated entity that encounters at least three different environments during each infectious cycle. We review current knowledge on its composition and morphology, and emerging metabolic activities. These features confer resistance to the extracellular environment, the ability to penetrate a host cell and ultimately enable the EB to establish a niche enabling bacterial survival and growth. The bacterial and host molecules involved in these processes are beginning to emerge.
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