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Maire J, Collingro A, Horn M, van Oppen MJH. Chlamydiae in corals: shared functional potential despite broad taxonomic diversity. ISME COMMUNICATIONS 2024; 4:ycae054. [PMID: 38707840 PMCID: PMC11070183 DOI: 10.1093/ismeco/ycae054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/15/2024] [Accepted: 04/09/2024] [Indexed: 05/07/2024]
Abstract
Cnidarians, such as corals and sea anemones, associate with a wide range of bacteria that have essential functions, including nutrient cycling and the production of antimicrobial compounds. Within cnidarians, bacteria can colonize all microhabitats including the tissues. Among them are obligate intracellular bacteria of the phylum Chlamydiota (chlamydiae) whose impact on cnidarian hosts and holobionts, especially corals, remain unknown. Here, we conducted a meta-analysis of previously published 16S rRNA gene metabarcoding data from cnidarians (e.g. coral, jellyfish, and anemones), eight metagenome-assembled genomes (MAGs) of coral-associated chlamydiae, and one MAG of jellyfish-associated chlamydiae to decipher their diversity and functional potential. While the metabarcoding dataset showed an enormous diversity of cnidarian-associated chlamydiae, six out of nine MAGs were affiliated with the Simkaniaceae family. The other three MAGs were assigned to the Parasimkaniaceae, Rhabdochlamydiaceae, and Anoxychlamydiaceae, respectively. All MAGs lacked the genes necessary for an independent existence, lacking any nucleotide or vitamin and most amino acid biosynthesis pathways. Hallmark chlamydial genes, such as a type III secretion system, nucleotide transporters, and genes for host interaction, were encoded in all MAGs. Together these observations suggest an obligate intracellular lifestyle of coral-associated chlamydiae. No unique genes were found in coral-associated chlamydiae, suggesting a lack of host specificity. Additional studies are needed to understand how chlamydiae interact with their coral host, and other microbes in coral holobionts. This first study of the diversity and functional potential of coral-associated chlamydiae improves our understanding of both the coral microbiome and the chlamydial lifestyle and host range.
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Affiliation(s)
- Justin Maire
- School of BioSciences, The University of Melbourne, Parkville 3010, VIC, Australia
| | - Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Madeleine J H van Oppen
- School of BioSciences, The University of Melbourne, Parkville 3010, VIC, Australia
- Australian Institute of Marine Science, PMB No 3, Townsville 4810, QLD, Australia
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2
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Abstract
Type III secretion systems (T3SSs) are utilized by Gram-negative pathogens to enhance their pathogenesis. This secretion system is associated with the delivery of effectors through a needle-like structure from the bacterial cytosol directly into a target eukaryotic cell. These effector proteins then manipulate specific eukaryotic cell functions to benefit pathogen survival within the host. The obligate intracellular pathogens of the family Chlamydiaceae have a highly evolutionarily conserved nonflagellar T3SS that is an absolute requirement for their survival and propagation within the host with about one-seventh of the genome dedicated to genes associated with the T3SS apparatus, chaperones, and effectors. Chlamydiae also have a unique biphasic developmental cycle where the organism alternates between an infectious elementary body (EB) and replicative reticulate body (RB). T3SS structures have been visualized on both EBs and RBs. And there are effector proteins that function at each stage of the chlamydial developmental cycle, including entry and egress. This review will discuss the history of the discovery of chlamydial T3SS and the biochemical characterization of components of the T3SS apparatus and associated chaperones in the absence of chlamydial genetic tools. These data will be contextualized into how the T3SS apparatus functions throughout the chlamydial developmental cycle and the utility of heterologous/surrogate models to study chlamydial T3SS. Finally, there will be a targeted discussion on the history of chlamydial effectors and recent advances in the field.
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Affiliation(s)
- Elizabeth A. Rucks
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Durham Research Center II, Omaha, Nebraska, USA
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3
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Maire J, Tandon K, Collingro A, van de Meene A, Damjanovic K, Gotze CR, Stephenson S, Philip GK, Horn M, Cantin NE, Blackall LL, van Oppen MJH. Colocalization and potential interactions of Endozoicomonas and chlamydiae in microbial aggregates of the coral Pocillopora acuta. SCIENCE ADVANCES 2023; 9:eadg0773. [PMID: 37196086 DOI: 10.1126/sciadv.adg0773] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/13/2023] [Indexed: 05/19/2023]
Abstract
Corals are associated with a variety of bacteria, which occur in the surface mucus layer, gastrovascular cavity, skeleton, and tissues. Some tissue-associated bacteria form clusters, termed cell-associated microbial aggregates (CAMAs), which are poorly studied. Here, we provide a comprehensive characterization of CAMAs in the coral Pocillopora acuta. Combining imaging techniques, laser capture microdissection, and amplicon and metagenome sequencing, we show that (i) CAMAs are located in the tentacle tips and may be intracellular; (ii) CAMAs contain Endozoicomonas (Gammaproteobacteria) and Simkania (Chlamydiota) bacteria; (iii) Endozoicomonas may provide vitamins to its host and use secretion systems and/or pili for colonization and aggregation; (iv) Endozoicomonas and Simkania occur in distinct, but adjacent, CAMAs; and (v) Simkania may receive acetate and heme from neighboring Endozoicomonas. Our study provides detailed insight into coral endosymbionts, thereby improving our understanding of coral physiology and health and providing important knowledge for coral reef conservation in the climate change era.
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Affiliation(s)
- Justin Maire
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Kshitij Tandon
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Allison van de Meene
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Katarina Damjanovic
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Cecilie Ravn Gotze
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Sophie Stephenson
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Gayle K Philip
- Melbourne Bioinformatics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna 1030, Austria
| | - Neal E Cantin
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
| | - Linda L Blackall
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Madeleine J H van Oppen
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Australian Institute of Marine Science, PMB No 3, Townsville, QLD 4810, Australia
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4
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Pitt R, Doyle R, Theilgaard Christiansen M, Horner P, Hathorn E, Alexander S, Woodford N, Cole M, Breuer J. Whole-genome sequencing of Chlamydia trachomatis isolates from persistently infected patients. Int J STD AIDS 2022; 33:442-446. [PMID: 35239412 DOI: 10.1177/09564624211048662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Current understanding of the causes of treatment failure in Chlamydia trachomatis is poor and antimicrobial susceptibility data are lacking. We used genome sequencing to seek evidence of antimicrobial resistance in isolates sourced from patients who were persistently infected. METHODS Genomic DNA was extracted from C. trachomatis isolates cultured in McCoy cell monolayers. Sequencing libraries were prepared using the SureSelectXT Illumina paired-end protocol. Paired reads were mapped against a reference genome and single nucleotide variants (SNVs) were identified. RESULTS Seven isolates from persistently infected patients and five isolates from successfully treated patients were sequenced. No previously reported SNVs associated with antimicrobial resistance were found. A unique SNV was identified in the gyrA gene of one treatment failure isolate but was located outside of the quinolone resistance determining region; this SNV has been previously reported in other members of the Chlamydiaceae family. CONCLUSION No genomic evidence was found to explain the differences in clinical outcome for our two groups of patients. A mutation unrelated to antimicrobial susceptibility was found in an isolate from a persistently infected patient. The cause of these persistent infections with C. trachomatis remains unclear.
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Affiliation(s)
- Rachel Pitt
- National Infection Service, Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI), 372064Public Health England, London, UK
| | - Ronan Doyle
- Division of Infection and Immunity, 4919University College London, London, UK
| | | | - Paddy Horner
- Population Health Sciences, 1980University of Bristol, Bristol, UK.,Unity Sexual Health, 1984University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Emma Hathorn
- Whittal Street Clinic, 1732University Hospitals Birmingham, Birmingham, UK
| | - Sarah Alexander
- Sexually Transmitted Bacteria Reference Unit, 371011Public Health England, London, UK
| | - Neil Woodford
- National Infection Service, Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI), 372064Public Health England, London, UK
| | - Michelle Cole
- National Infection Service, Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI), 372064Public Health England, London, UK
| | - Judith Breuer
- Division of Infection and Immunity, 4919University College London, London, UK
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Bugalhão JN, Mota LJ. The multiple functions of the numerous Chlamydia trachomatis secreted proteins: the tip of the iceberg. MICROBIAL CELL 2019; 6:414-449. [PMID: 31528632 PMCID: PMC6717882 DOI: 10.15698/mic2019.09.691] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chlamydia trachomatis serovars are obligate intracellular bacterial pathogens mainly causing ocular and urogenital infections that affect millions of people worldwide and which can lead to blindness or sterility. They reside and multiply intracellularly within a membrane-bound vacuolar compartment, known as inclusion, and are characterized by a developmental cycle involving two morphologically and physiologically distinct chlamydial forms. Completion of the developmental cycle involves the secretion of > 70 C. trachomatis proteins that function in the host cell cytoplasm and nucleus, in the inclusion membrane and lumen, and in the extracellular milieu. These proteins can, for example, interfere with the host cell cytoskeleton, vesicular and non-vesicular transport, metabolism, and immune signalling. Generally, this promotes C. trachomatis invasion into, and escape from, host cells, the acquisition of nutrients by the chlamydiae, and evasion of cell-autonomous, humoral and cellular innate immunity. Here, we present an in-depth review on the current knowledge and outstanding questions about these C. trachomatis secreted proteins.
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Affiliation(s)
- Joana N Bugalhão
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Luís Jaime Mota
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
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Abstract
Antibiotic resistance is a major public health threat that has stimulated the scientific community to search for nontraditional therapeutic targets. Because virulence, but not the growth, of many Gram-negative bacterial pathogens depends on the multicomponent type three secretion system injectisome (T3SSi), the T3SSi has been an attractive target for identifying small molecules, peptides, and monoclonal antibodies that inhibit its function to render the pathogen avirulent. While many small-molecule lead compounds have been identified in whole-cell-based high-throughput screens (HTSs), only a few protein targets of these compounds are known; such knowledge is an important step to developing more potent and specific inhibitors. Evaluation of the efficacy of compounds in animal studies is ongoing. Some efforts involving the development of antibodies and vaccines that target the T3SSi are further along and include an antibody that is currently in phase II clinical trials. Continued research into these antivirulence therapies, used alone or in combination with traditional antibiotics, requires combined efforts from both pharmaceutical companies and academic labs.
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Zhang H, Vellappan S, Tang MM, Bao X, Fan H. GrgA as a potential target of selective antichlamydials. PLoS One 2019; 14:e0212874. [PMID: 30822328 PMCID: PMC6396966 DOI: 10.1371/journal.pone.0212874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/11/2019] [Indexed: 01/16/2023] Open
Abstract
Chlamydia is a common pathogen that can causes serious complications in the reproductive system and eyes. Lack of vaccine and other effective prophylactic measures coupled with the largely asymptomatic nature and unrare clinical treatment failure calls for development of new antichlamydials, particularly selective antichlamydials without adverse effects on humans and the beneficial microbiota. We previously reported that benzal-N-acylhydrazones (BAH) can inhibit chlamydiae without detectable adverse effects on host cells and beneficial lactobacilli that dominate the human vaginal microbiota among reproductive-age women. However, the antichlamydial mechanism of BAH is not known. Whereas 4 single nucleotide polymorphisms (i.e., SNP1-4) were identified in a rare Chlamydia variant with a low level of BAH resistance, termed MCR, previous studies failed to establish a causal effect of any particular SNP(s). In the present work, we performed recombination to segregate the four SNPs. Susceptibility tests indicate that the R51G GrgA allele is both necessary and sufficient for the low level of BAH resistance. Thus, the Chlamydia-specific transcription factor GrgA either is a direct target of BAH or regulates BAH susceptibility. We further confirm an extremely low rate of BAH resistance in Chlamydia. Our findings warrant exploration of GrgA as a therapeutic and prophylactic target for chlamydial infections.
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Affiliation(s)
- Huirong Zhang
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, United States of America
| | - Sangeevan Vellappan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, United States of America
- The George H. Cook Undergraduate Honors Scholars Program, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
| | - M. Matt Tang
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, United States of America
- Graduate Program in Physiology and Integrative Biology, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Xiaofeng Bao
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, United States of America
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, China
| | - Huizhou Fan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, United States of America
- Graduate Program in Physiology and Integrative Biology, Rutgers University, New Brunswick, New Jersey, United States of America
- * E-mail:
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8
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Beder T, Saluz HP. Virulence-related comparative transcriptomics of infectious and non-infectious chlamydial particles. BMC Genomics 2018; 19:575. [PMID: 30068313 PMCID: PMC6090853 DOI: 10.1186/s12864-018-4961-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 07/25/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Members of the phylum Chlamydiae are obligate intracellular pathogens of humans and animals and have a serious impact on host health. They comprise several zoonotic species with varying disease outcomes and prevalence. To investigate differences in virulence, we focused on Chlamydia psittaci, C. abortus and Waddlia chondrophila. Most threatening is C. psittaci, which frequently infects humans and causes psittacosis associated with severe pneumonia. The closest relative of C. psittaci is C. abortus, which shares the vast majority of genes but less frequently infects humans, and causes stillbirth and sepsis. W. chondrophila is more distantly related, and occasional human infections are associated with respiratory diseases or miscarriage. One possible explanation for differences in virulence originate from species-specific genes as well as differentially expressed homologous virulence factors. RESULTS RNA-sequencing (RNA-Seq) was applied to purified infectious elementary bodies (EBs) and non-infectious reticulate bodies (RBs) in order to elucidate the transcriptome of the infectious and replicative chlamydial states. The results showed that approximately half of all genes were differentially expressed. For a descriptive comparison, genes were categorised according to their function in the RAST database. This list was extended by the inclusion of inclusion membrane proteins, outer membrane proteins, polymorphic membrane proteins and type III secretion system effectors. In addition, the expression of fifty-six known and a variety of predicted virulence and immunogenic factors with homologs in C. psittaci, C. abortus and W. chondrophila was analysed. To confirm the RNA-Seq results, the expression of nine factors was validated using real-time quantitative polymerase chain reaction (RT-qPCR). Comparison of RNA-Seq and RT-qPCR results showed a high mean Pearson correlation coefficient of 0.95. CONCLUSIONS It was shown that both the replicative and infectious chlamydial state contained distinctive transcriptomes and the cellular processes emphasised in EBs and RBs differed substantially based on the chlamydial species. In addition, the very first interspecies transcriptome comparison is presented here, and the considerable differences in expression of homologous virulence factors might contribute to the differing infection rates and disease outcomes of the pathogens. The RNA-Seq results were confirmed by RT-qPCR and demonstrate the feasibility of interspecies transcriptome comparisons in chlamydia.
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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), Beutenbergstraße 11A, 07745, Jena, Germany.,Network Modelling, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Beutenbergstraße 11A, 07745, Jena, Germany.,Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
| | - Hans Peter Saluz
- Department of Cell and Molecular Biology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Beutenbergstraße 11A, 07745, Jena, Germany. .,Friedrich Schiller University, Fürstengraben 1, 07743, Jena, Germany.
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Cossé MM, Barta ML, Fisher DJ, Oesterlin LK, Niragire B, Perrinet S, Millot GA, Hefty PS, Subtil A. The Loss of Expression of a Single Type 3 Effector (CT622) Strongly Reduces Chlamydia trachomatis Infectivity and Growth. Front Cell Infect Microbiol 2018; 8:145. [PMID: 29868501 PMCID: PMC5962693 DOI: 10.3389/fcimb.2018.00145] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/20/2018] [Indexed: 12/20/2022] Open
Abstract
Invasion of epithelial cells by the obligate intracellular bacterium Chlamydia trachomatis results in its enclosure inside a membrane-bound compartment termed an inclusion. The bacterium quickly begins manipulating interactions between host intracellular trafficking and the inclusion interface, diverging from the endocytic pathway and escaping lysosomal fusion. We have identified a previously uncharacterized protein, CT622, unique to the Chlamydiaceae, in the absence of which most bacteria failed to establish a successful infection. CT622 is abundant in the infectious form of the bacteria, in which it associates with CT635, a putative novel chaperone protein. We show that CT622 is translocated into the host cytoplasm via type three secretion throughout the developmental cycle of the bacteria. Two separate domains of roughly equal size have been identified within CT622 and a 1.9 Å crystal structure of the C-terminal domain has been determined. Genetic disruption of ct622 expression resulted in a strong bacterial growth defect, which was due to deficiencies in proliferation and in the generation of infectious bacteria. Our results converge to identify CT622 as a secreted protein that plays multiple and crucial roles in the initiation and support of the C. trachomatis growth cycle. They reveal that genetic disruption of a single effector can deeply affect bacterial fitness.
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Affiliation(s)
- Mathilde M Cossé
- Unité de Biologie Cellulaire de l'Infection Microbienne, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique UMR3691, Paris, France.,Collège Doctoral, Sorbonne Université, Paris, France
| | - Michael L Barta
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States
| | - Derek J Fisher
- Department of Microbiology, Southern Illinois University, Carbondale, IL, United States
| | - Lena K Oesterlin
- Institut Curie, PSL Research University, Centre National de la Recherche Scientifique UMR 144, Molecular Mechanisms of Intracellular Transport, Paris, France
| | - Béatrice Niragire
- Unité de Biologie Cellulaire de l'Infection Microbienne, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique UMR3691, Paris, France
| | - Stéphanie Perrinet
- Unité de Biologie Cellulaire de l'Infection Microbienne, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique UMR3691, Paris, France
| | - Gaël A Millot
- Institut Pasteur-Bioinformatics and Biostatistics Hub-C3BI, USR3756 IP Centre National de la Recherche Scientifique, Paris, France
| | - P Scott Hefty
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States
| | - Agathe Subtil
- Unité de Biologie Cellulaire de l'Infection Microbienne, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique UMR3691, Paris, France
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10
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Zhang H, Kunadia A, Lin Y, Fondell JD, Seidel D, Fan H. Identification of a strong and specific antichlamydial N-acylhydrazone. PLoS One 2017; 12:e0185783. [PMID: 28973037 PMCID: PMC5626472 DOI: 10.1371/journal.pone.0185783] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 09/19/2017] [Indexed: 12/02/2022] Open
Abstract
Sexually transmitted Chlamydia trachomatis is an extremely common infection and often leads to serious complications including infertility and pelvic inflammatory syndrome. Several broad-spectrum antibiotics are currently used to treat C. trachomatis. Although effective, they also kill beneficial vaginal lactobacilli. Two N-acylhydrazones, CF0001 and CF0002, have been shown previously to inhibit chlamydial growth without toxicity to human cells and Lactobacillus spp. Of particular significance, the rate of random mutation leading to resistance of these inhibitors appears to be extremely low. Here, we report three analogs of CF0001 and CF0002 with significantly stronger inhibitory effects on chlamydiae. Even though the new compounds (termed SF1, SF2 and SF3) displayed slightly decreased inhibition efficiencies for a rare Chlamydia variant selected for CF0001 resistance (Chlamydia muridarum MCR), they completely overcame the resistance when used at concentrations of 75–100 μM. Importantly, SF1, SF2 and SF3 did not shown any toxic effect on lactobacilli, whereas SF3 was also well tolerated by human host cells. An effort to isolate SF3-resistant variants was unsuccessful. By comparison, variants resistant to rifampin or spectinomycin were obtained from smaller numbers of chlamydiae. Our findings suggest that SF3 utilizes an antichlamydial mechanism similar to that of CF0001 and CF0002, and will be more difficult for chlamydiae to develop resistance to, potentially making it a more effective antichlamydial agent.
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Affiliation(s)
- Huirong Zhang
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Anuj Kunadia
- Department of Chemistry and Chemical Biology, School of Arts and Sciences, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Yingfu Lin
- Department of Chemistry and Chemical Biology, School of Arts and Sciences, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Joseph D. Fondell
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Daniel Seidel
- Department of Chemistry and Chemical Biology, School of Arts and Sciences, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail: (DS); (HF)
| | - Huizhou Fan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail: (DS); (HF)
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11
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N-Acylated Derivatives of Sulfamethoxazole Block Chlamydia Fatty Acid Synthesis and Interact with FabF. Antimicrob Agents Chemother 2017; 61:AAC.00716-17. [PMID: 28784680 DOI: 10.1128/aac.00716-17] [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: 04/06/2017] [Accepted: 07/28/2017] [Indexed: 12/24/2022] Open
Abstract
The type II fatty acid synthesis (FASII) pathway is essential for bacterial lipid biosynthesis and continues to be a promising target for novel antibacterial compounds. Recently, it has been demonstrated that Chlamydia is capable of FASII and this pathway is indispensable for Chlamydia growth. Previously, a high-content screen with Chlamydia trachomatis-infected cells was performed, and acylated sulfonamides were identified to be potent growth inhibitors of the bacteria. C. trachomatis strains resistant to acylated sulfonamides were isolated by serial passage of a wild-type strain in the presence of low compound concentrations. Results from whole-genome sequencing of 10 isolates from two independent drug-resistant populations revealed that mutations that accumulated in fabF were predominant. Studies of the interaction between the FabF protein and small molecules showed that acylated sulfonamides directly bind to recombinant FabF in vitro and treatment of C. trachomatis-infected HeLa cells with the compounds leads to a decrease in the synthesis of Chlamydia fatty acids. This work demonstrates the importance of FASII for Chlamydia development and may lead to the development of new antimicrobials.
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12
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da Cunha M, Pais SV, Bugalhão JN, Mota LJ. The Chlamydia trachomatis type III secretion substrates CT142, CT143, and CT144 are secreted into the lumen of the inclusion. PLoS One 2017. [PMID: 28622339 PMCID: PMC5473537 DOI: 10.1371/journal.pone.0178856] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Chlamydia trachomatis is a human bacterial pathogen causing ocular and genital infections. It multiplies exclusively within an intracellular membrane-bound vacuole, the inclusion, and uses a type III secretion system to manipulate host cells by injecting them with bacterially-encoded effector proteins. In this work, we characterized the expression and subcellular localization in infected host cells of the C. trachomatis CT142, CT143, and CT144 proteins, which we previously showed to be type III secretion substrates. Transcriptional analyses in C. trachomatis confirmed the prediction that ct142, ct143 and ct144 are organized in an operon and revealed that their expression is likely driven by the main σ factor, σ66. In host cells infected by C. trachomatis, production of CT142 and CT143 could be detected by immunoblotting from 20–26 h post-infection. Immunofluorescence microscopy of infected cells revealed that from 20 h post-infection CT143 appeared mostly as globular structures outside of the bacterial cells but within the lumen of the inclusion. Furthermore, immunofluorescence microscopy of cells infected by C. trachomatis strains carrying plasmids producing CT142, CT143, or CT144 under the control of the ct142 promoter and with a C-terminal double hemagglutinin (2HA) epitope tag revealed that CT142-2HA, CT143-2HA or CT144-2HA showed an identical localization to chromosomally-encoded CT143. Moreover, CT142-2HA or CT144-2HA and CT143 produced by the same bacteria co-localized in the lumen of the inclusion. Overall, these data suggest that the CT142, CT143, and CT144 type III secretion substrates are secreted into the lumen of the inclusion where they might form a protein complex.
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Affiliation(s)
- Maria da Cunha
- UCIBIO—REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sara V. Pais
- UCIBIO—REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Joana N. Bugalhão
- UCIBIO—REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Luís Jaime Mota
- UCIBIO—REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- * E-mail:
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Salicylidene Acylhydrazides and Hydroxyquinolines Act as Inhibitors of Type Three Secretion Systems in Pseudomonas aeruginosa by Distinct Mechanisms. Antimicrob Agents Chemother 2017; 61:AAC.02566-16. [PMID: 28396545 DOI: 10.1128/aac.02566-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 03/23/2017] [Indexed: 12/27/2022] Open
Abstract
Type 3 secretion systems (T3SSs) are major virulence factors in Gram-negative bacteria. Pseudomonas aeruginosa expresses two T3SSs, namely, an injectisome (iT3SS) translocating effector proteins in the host cell cytosol and a flagellum (fT3SS) ensuring bacterial motility. Inhibiting these systems is an appealing therapeutic strategy for acute infections. This study examines the protective effects of the salicylidene acylhydrazide INP0341 and of the hydroxyquinoline INP1750 (previously described as T3SS inhibitors in other species) toward cytotoxic effects of P. aeruginosain vitro Both compounds reduced cell necrosis and inflammasome activation induced by reference strains or clinical isolates expressing T3SS toxins or only the translocation apparatus. INP0341 inhibited iT3SS transcriptional activation, including in strains with constitutive iT3SS expression, and reduced the total expression of toxins, suggesting it targets iT3SS gene transcription. INP1750 inhibited toxin secretion and flagellar motility and impaired the activity of the YscN ATPase from Yersinia pseudotuberculosis (homologous to the ATPase present in the basal body of P. aeruginosa iT3SS and fT3SS), suggesting that it rather targets a T3SS core constituent with high homology among iT3SS and fT3SS. This mode of action is similar to that previously described for INP1855, another hydroxyquinoline, against P. aeruginosa Thus, although acting by different mechanisms, INP0341 and INP1750 appear as useful inhibitors of the virulence of P. aeruginosa Hydroxyquinolines may have a broader spectrum of activity by the fact they act upon two virulence factors (iT3SS and fT3SS).
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Hakobyan S, Rzhepishevska O, Björn E, Boily JF, Ramstedt M. Influence of chelation strength and bacterial uptake of gallium salicylidene acylhydrazide on biofilm formation and virulence of Pseudomonas aeruginosa. J Inorg Biochem 2016; 160:24-32. [DOI: 10.1016/j.jinorgbio.2016.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 03/07/2016] [Accepted: 04/04/2016] [Indexed: 01/13/2023]
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15
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McShan AC, De Guzman RN. The bacterial type III secretion system as a target for developing new antibiotics. Chem Biol Drug Des 2015; 85:30-42. [PMID: 25521643 DOI: 10.1111/cbdd.12422] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 01/14/2023]
Abstract
Antibiotic resistance in pathogens requires new targets for developing novel antibacterials. The bacterial type III secretion system (T3SS) is an attractive target for developing antibacterials as it is essential in the pathogenesis of many Gram-negative bacteria. The T3SS consists of structural proteins, effectors, and chaperones. Over 20 different structural proteins assemble into a complex nanoinjector that punctures a hole on the eukaryotic cell membrane to allow the delivery of effectors directly into the host cell cytoplasm. Defects in the assembly and function of the T3SS render bacteria non-infective. Two major classes of small molecules, salicylidene acylhydrazides and thiazolidinones, have been shown to inhibit multiple genera of bacteria through the T3SS. Many additional chemically and structurally diverse classes of small molecule inhibitors of the T3SS have been identified as well. While specific targets within the T3SS of a few inhibitors have been suggested, the vast majority of specific protein targets within the T3SS remain to be identified or characterized. Other T3SS inhibitors include polymers, proteins, and polypeptides mimics. In addition, T3SS activity is regulated by its interaction with biologically relevant molecules, such as bile salts and sterols, which could serve as scaffolds for drug design.
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Affiliation(s)
- Andrew C McShan
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66045, USA
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16
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Mueller KE, Fields KA. Application of β-lactamase reporter fusions as an indicator of effector protein secretion during infections with the obligate intracellular pathogen Chlamydia trachomatis. PLoS One 2015; 10:e0135295. [PMID: 26258949 PMCID: PMC4530969 DOI: 10.1371/journal.pone.0135295] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/20/2015] [Indexed: 02/05/2023] Open
Abstract
Chlamydia spp. utilize multiple secretion systems, including the type III secretion system (T3SS), to deploy host-interactive effector proteins into infected host cells. Elucidation of secreted proteins has traditionally required ectopic expression in a surrogate T3SS followed by immunolocalization of endogenous candidate effectors to confirm secretion by chlamydiae. The ability to transform Chlamydia and achieve stable expression of recombinant gene products has enabled a more direct assessment of secretion. We adapted TEM-1 β-lactamase as a reporter system for assessment of chlamydial protein secretion. We provide evidence that this system facilitates visualization of secretion in the context of infection. Specifically, our findings provide definitive evidence that C. trachomatis CT695 is secreted during infection. Follow-up indirect immunofluorescence studies confirmed CT695 secretion and indicate that this effector can be secreted at multiple points during the chlamydial developmental cycle. Our results indicate that the BlaM-fusion reporter assay will allow efficacious identification of novel secreted proteins. Moreover, this approach can easily be adapted to enable more sophisticated studies of the secretion process in Chlamydia.
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Affiliation(s)
- Konrad E. Mueller
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States of America
| | - Kenneth A. Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States of America
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Chlamydia trachomatis In Vivo to In Vitro Transition Reveals Mechanisms of Phase Variation and Down-Regulation of Virulence Factors. PLoS One 2015. [PMID: 26207372 PMCID: PMC4514472 DOI: 10.1371/journal.pone.0133420] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Research on the obligate intracellular bacterium Chlamydia trachomatis demands culture in cell-lines, but the adaptive process behind the in vivo to in vitro transition is not understood. We assessed the genomic and transcriptomic dynamics underlying C. trachomatis in vitro adaptation of strains representing the three disease groups (ocular, epithelial-genital and lymphogranuloma venereum) propagated in epithelial cells over multiple passages. We found genetic features potentially underlying phase variation mechanisms mediating the regulation of a lipid A biosynthesis enzyme (CT533/LpxC), and the functionality of the cytotoxin (CT166) through an ON/OFF mechanism. We detected inactivating mutations in CT713/porB, a scenario suggesting metabolic adaptation to the available carbon source. CT135 was inactivated in a tropism-specific manner, with CT135-negative clones emerging for all epithelial-genital populations (but not for LGV and ocular populations) and rapidly increasing in frequency (~23% mutants per 10 passages). RNA-sequencing analyses revealed that a deletion event involving CT135 impacted the expression of multiple virulence factors, namely effectors known to play a role in the C. trachomatis host-cell invasion or subversion (e.g., CT456/Tarp, CT694, CT875/TepP and CT868/ChlaDub1). This reflects a scenario of attenuation of C. trachomatis virulence in vitro, which may take place independently or in a cumulative fashion with the also observed down-regulation of plasmid-related virulence factors. This issue may be relevant on behalf of the recent advances in Chlamydia mutagenesis and transformation where culture propagation for selecting mutants/transformants is mandatory. Finally, there was an increase in the growth rate for all strains, reflecting gradual fitness enhancement over time. In general, these data shed light on the adaptive process underlying the C. trachomatis in vivo to in vitro transition, and indicates that it would be prudent to restrict culture propagation to minimal passages and check the status of the CT135 genotype in order to avoid the selection of CT135-negative mutants, likely originating less virulent strains.
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Sunduru N, Salin O, Gylfe Å, Elofsson M. Design, synthesis and evaluation of novel polypharmacological antichlamydial agents. Eur J Med Chem 2015. [PMID: 26204507 DOI: 10.1016/j.ejmech.2015.07.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Discovery of new polypharmacological antibacterial agents with multiple modes of actions can be an alternative to combination therapy and also a possibility to slow development of antibiotic resistance. In support to this hypothesis, we synthesized 16 compounds by combining the pharmacophores of Chlamydia trachomatis inhibitors and inhibitors of type III secretion (T3S) in gram-negative bacteria. In this study we have developed salicylidene acylhydrazide sulfonamides (11c &11d) as new antichlamydial agents that also inhibit T3S in Yersinia pseudotuberculosis.
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Affiliation(s)
- Naresh Sunduru
- Department of Chemistry, Umeå University, SE90187 Umeå, Sweden; Umeå Centre for Microbial Research (UCMR), SE90187 Umeå, Sweden
| | - Olli Salin
- Department of Chemistry, Umeå University, SE90187 Umeå, Sweden; Department of Clinical Microbiology, Umeå University, SE90187 Umeå, Sweden; Umeå Centre for Microbial Research (UCMR), SE90187 Umeå, Sweden
| | - Åsa Gylfe
- Department of Chemistry, Umeå University, SE90187 Umeå, Sweden; Umeå Centre for Microbial Research (UCMR), SE90187 Umeå, Sweden; Molecular Infection Medicine Sweden (MIMS), Umeå University, SE90187 Umeå, Sweden
| | - Mikael Elofsson
- Department of Chemistry, Umeå University, SE90187 Umeå, Sweden; Umeå Centre for Microbial Research (UCMR), SE90187 Umeå, Sweden.
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Identification of in vivo-induced bacterial protein antigens during calf infection with Chlamydia psittaci. Int J Med Microbiol 2015; 305:310-21. [DOI: 10.1016/j.ijmm.2014.12.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 11/19/2014] [Accepted: 12/20/2014] [Indexed: 01/21/2023] Open
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20
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Charro N, Mota LJ. Approaches targeting the type III secretion system to treat or prevent bacterial infections. Expert Opin Drug Discov 2015; 10:373-87. [DOI: 10.1517/17460441.2015.1019860] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Nuno Charro
- 1UCIBIO, REQUIMTE, Departmento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica 2829-516, Portugal
| | - Luís Jaime Mota
- 2UCIBIO, REQUIMTE, Departmento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica 2829-516, Portugal ;
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21
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Expansion of the Chlamydia trachomatis inclusion does not require bacterial replication. Int J Med Microbiol 2015; 305:378-82. [PMID: 25771502 DOI: 10.1016/j.ijmm.2015.02.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/14/2015] [Accepted: 02/22/2015] [Indexed: 01/20/2023] Open
Abstract
Chlamydia trachomatis replication takes place inside of a host cell, exclusively within a vacuole known as the inclusion. During an infection, the inclusion expands to accommodate the increasing numbers of C. trachomatis. However, whether inclusion expansion requires bacterial replication and/or de novo protein synthesis has not been previously investigated in detail. Therefore, using a chemical biology approach, we herein investigated C. trachomatis inclusion expansion under varying conditions in vitro. Under normal cell culture conditions, inclusion expansion correlated with C. trachomatis replication. When bacterial replication was inhibited using KSK120, an inhibitor that targets C. trachomatis glucose metabolism, inclusions expanded even in the absence of bacterial replication. In contrast, when bacterial protein synthesis was inhibited using chloramphenicol, expansion of inclusions was blocked. Together, these data suggest that de novo protein synthesis is necessary, whereas bacterial replication is dispensable for C. trachomatis inclusion expansion.
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The type III secretion system (T3SS) of Chlamydophila psittaci is involved in the host inflammatory response by activating the JNK/ERK signaling pathway. BIOMED RESEARCH INTERNATIONAL 2015; 2015:652416. [PMID: 25685800 PMCID: PMC4317586 DOI: 10.1155/2015/652416] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/21/2014] [Accepted: 10/05/2014] [Indexed: 12/03/2022]
Abstract
Chlamydophila psittaci (C. psittaci) is a human zoonotic pathogen, which could result in severe respiratory disease. In the present study, we investigated the role and mechanism of the type III secretion system (T3SS) of C. psittaci in regulating the inflammatory response in host cells. C. psittaci-infected THP-1 cells were incubated with the specific T3SS inhibitor INP0007, inhibitors of ERK, p38, or JNK, and the levels of inflammatory cytokines were analyzed using Q-PCR and ELISA. The levels of ERK, p38, and JNK phosphorylation were analyzed by Western blot. Our results verified that INP0007 inhibited chlamydial growth in vitro, but the coaddition of exogenous iron completely reversed the growth deficit. INP0007 inhibited the growth of C. psittaci and decreased the levels of IL-8, IL-6, TNF-α, and IL-1β. Exogenous iron restored the chlamydial growth but not the production of inflammatory cytokines. These results demonstrated that the expression of inflammatory cytokines during infection was associated with the T3SS which reduced by incubation with ERK and JNK inhibitors, but not with p38 inhibitor. We concluded that the T3SS elicited inflammatory responses by activating the JNK or ERK signaling pathways in the infection of C. psittaci.
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23
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Abstract
In a screen for compounds that inhibit infectivity of the obligate intracellular pathogen Chlamydia trachomatis, we identified the 2-pyridone amide KSK120. A fluorescent KSK120 analogue was synthesized and observed to be associated with the C. trachomatis surface, suggesting that its target is bacterial. We isolated KSK120-resistant strains and determined that several resistance mutations are in genes that affect the uptake and use of glucose-6-phosphate (G-6P). Consistent with an effect on G-6P metabolism, treatment with KSK120 blocked glycogen accumulation. Interestingly, KSK120 did not affect Escherichia coli or the host cell. Thus, 2-pyridone amides may represent a class of drugs that can specifically inhibit C. trachomatis infection. Chlamydia trachomatis is a bacterial pathogen of humans that causes a common sexually transmitted disease as well as eye infections. It grows only inside cells of its host organism, within a parasitophorous vacuole termed the inclusion. Little is known, however, about what bacterial components and processes are important for C. trachomatis cellular infectivity. Here, by using a visual screen for compounds that affect bacterial distribution within the chlamydial inclusion, we identified the inhibitor KSK120. As hypothesized, the altered bacterial distribution induced by KSK120 correlated with a block in C. trachomatis infectivity. Our data suggest that the compound targets the glucose-6-phosphate (G-6P) metabolism pathway of C. trachomatis, supporting previous indications that G-6P metabolism is critical for C. trachomatis infectivity. Thus, KSK120 may be a useful tool to study chlamydial glucose metabolism and has the potential to be used in the treatment of C. trachomatis infections.
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24
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Christiansen MT, Brown AC, Kundu S, Tutill HJ, Williams R, Brown JR, Holdstock J, Holland MJ, Stevenson S, Dave J, Tong CYW, Einer-Jensen K, Depledge DP, Breuer J. Whole-genome enrichment and sequencing of Chlamydia trachomatis directly from clinical samples. BMC Infect Dis 2014; 14:591. [PMID: 25388670 PMCID: PMC4233057 DOI: 10.1186/s12879-014-0591-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/27/2014] [Indexed: 12/30/2022] Open
Abstract
Background Chlamydia trachomatis is a pathogen of worldwide importance, causing more than 100 million cases of sexually transmitted infections annually. Whole-genome sequencing is a powerful high resolution tool that can be used to generate accurate data on bacterial population structure, phylogeography and mutations associated with antimicrobial resistance. The objective of this study was to perform whole-genome enrichment and sequencing of C. trachomatis directly from clinical samples. Methods C. trachomatis positive samples comprising seven vaginal swabs and three urine samples were sequenced without prior in vitro culture in addition to nine cultured C. trachomatis samples, representing different serovars. A custom capture RNA bait set, that captures all known diversity amongst C. trachomatis genomes, was used in a whole-genome enrichment step during library preparation to enrich for C. trachomatis DNA. All samples were sequenced on the MiSeq platform. Results Full length C. trachomatis genomes (>95-100% coverage of a reference genome) were successfully generated for eight of ten clinical samples and for all cultured samples. The proportion of reads mapping to C. trachomatis and the mean read depth across each genome were strongly linked to the number of bacterial copies within the original sample. Phylogenetic analysis confirmed the known population structure and the data showed potential for identification of minority variants and mutations associated with antimicrobial resistance. The sensitivity of the method was >10-fold higher than other reported methodologies. Conclusions The combination of whole-genome enrichment and deep sequencing has proven to be a non-mutagenic approach, capturing all known variation found within C. trachomatis genomes. The method is a consistent and sensitive tool that enables rapid whole-genome sequencing of C. trachomatis directly from clinical samples and has the potential to be adapted to other pathogens with a similar clonal nature. Electronic supplementary material The online version of this article (doi:10.1186/s12879-014-0591-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mette T Christiansen
- Division of Infection and Immunity University College London (UCL), London, WC1E 6BT, UK.
| | - Amanda C Brown
- Oxford Gene Technology, Begbroke, Oxfordshire, OX5 1PF, UK. .,Present address: Department of Microbiology and Immunology, Cornell University, Ithaca, NY, 14853, USA.
| | - Samit Kundu
- Division of Infection and Immunity University College London (UCL), London, WC1E 6BT, UK. .,School of Human and Life Sciences, Canterbury Christchurch University, Canterbury, Kent, CT1 1QU, UK.
| | - Helena J Tutill
- Division of Infection and Immunity University College London (UCL), London, WC1E 6BT, UK.
| | - Rachel Williams
- Division of Infection and Immunity University College London (UCL), London, WC1E 6BT, UK.
| | | | | | - Martin J Holland
- London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK.
| | - Simon Stevenson
- University College London Hospital (UCLH), London, WC1E 6DE, UK.
| | | | | | | | - Daniel P Depledge
- Division of Infection and Immunity University College London (UCL), London, WC1E 6BT, UK.
| | - Judith Breuer
- Division of Infection and Immunity University College London (UCL), London, WC1E 6BT, UK.
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Bao X, Gylfe A, Sturdevant GL, Gong Z, Xu S, Caldwell HD, Elofsson M, Fan H. Benzylidene acylhydrazides inhibit chlamydial growth in a type III secretion- and iron chelation-independent manner. J Bacteriol 2014; 196:2989-3001. [PMID: 24914180 PMCID: PMC4135636 DOI: 10.1128/jb.01677-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 06/04/2014] [Indexed: 11/20/2022] Open
Abstract
Chlamydiae are widespread Gram-negative pathogens of humans and animals. Salicylidene acylhydrazides, developed as inhibitors of type III secretion system (T3SS) in Yersinia spp., have an inhibitory effect on chlamydial infection. However, these inhibitors also have the capacity to chelate iron, and it is possible that their antichlamydial effects are caused by iron starvation. Therefore, we have explored the modification of salicylidene acylhydrazides with the goal to uncouple the antichlamydial effect from iron starvation. We discovered that benzylidene acylhydrazides, which cannot chelate iron, inhibit chlamydial growth. Biochemical and genetic analyses suggest that the derivative compounds inhibit chlamydiae through a T3SS-independent mechanism. Four single nucleotide polymorphisms were identified in a Chlamydia muridarum variant resistant to benzylidene acylhydrazides, but it may be necessary to segregate the mutations to differentiate their roles in the resistance phenotype. Benzylidene acylhydrazides are well tolerated by host cells and probiotic vaginal Lactobacillus species and are therefore of potential therapeutic value.
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Affiliation(s)
- Xiaofeng Bao
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, USA Department of Pharmacology, Nantong University School of Pharmacy, Nantong, People's Republic of China
| | - Asa Gylfe
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Gail L Sturdevant
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Zheng Gong
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Shuang Xu
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Harlan D Caldwell
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | | | - Huizhou Fan
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
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N-acylated derivatives of sulfamethoxazole and sulfafurazole inhibit intracellular growth of Chlamydia trachomatis. Antimicrob Agents Chemother 2014; 58:2968-71. [PMID: 24566180 DOI: 10.1128/aac.02015-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Antibacterial compounds with novel modes of action are needed for management of bacterial infections. Here we describe a high-content screen of 9,800 compounds identifying acylated sulfonamides as novel growth inhibitors of the sexually transmitted pathogen Chlamydia trachomatis. The effect was bactericidal and distinct from that of sulfonamide antibiotics, as para-aminobenzoic acid did not reduce efficacy. Chemical inhibitors play an important role in Chlamydia research as probes of potential targets and as drug development starting points.
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27
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Marshall NC, Finlay BB. Targeting the type III secretion system to treat bacterial infections. Expert Opin Ther Targets 2013; 18:137-52. [DOI: 10.1517/14728222.2014.855199] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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28
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Abstract
Members of the order Chlamydiales comprise a group of exquisitely evolved parasites of eukaryotic hosts that extends from single-celled amoeba to mammals. The most notable are human pathogens and include the agent of oculogenital disease Chlamydia trachomatis, the respiratory pathogen C. pneumoniae, and the zoonotic agent C. psittaci. All of these species are obligate intracellular bacteria that develop within parasitophorous vesicles termed inclusions. This demanding lifestyle necessitates orchestrated entry into nonphagocytic cells, creation of a privileged intracellular niche, and subversion of potent host defenses. All chlamydial genomes contain the coding capacity for a nonflagellar type III secretion system, and this mechanism has arisen as an essential contributor to chlamydial virulence. The emergence of tractable approaches to the genetic manipulation of chlamydiae raises the possibility of explosive progress in understanding this important contributor to chlamydial pathogenesis. This minireview considers challenges and recent advances that have revealed how chlamydiae have maintained conserved aspects of T3S while exploiting diversification to yield a system that exerts a fundamental role in the unique biology of Chlamydia species.
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