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Wickramasinghe HC, Lincoln JN, D'Armond AE, Noble SA, Shen L, Macnaughtan MA. Insights into the association of the Chlamydia trachomatis type III secretion chaperone complex, Scc4:Scc1, from sequential expression in Escherichia coli. Protein Expr Purif 2024; 222:106532. [PMID: 38857716 DOI: 10.1016/j.pep.2024.106532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 06/03/2024] [Accepted: 06/08/2024] [Indexed: 06/12/2024]
Abstract
Chlamydia trachomatis (CT) is the bacterial pathogen responsible for causing the most common sexually transmitted disease in the United States. This obligate, intracellular Gram-negative bacterium has a type III secretion system (T3SS) to invade host cells. CopN is an important effector, plug protein that mediates early interactions between the host and Chlamydia. CopN is chaperoned by a heterodimer, T3SS chaperone complex containing Scc4 and Scc1. Scc4 is a unique, bifunctional protein that, in addition to its T3SS chaperone activity, acts as an RNA polymerase (RNAP) binding protein. We hypothesized that the two functions occur at different points in CT's developmental cycle with Scc4 acting alone in the early-to-mid stages and the Scc4:Scc1 complex chaperoning CopN in the mid-to-late stages. To study the Scc4:Scc1 complex by NMR, we previously explored various methods of associating Scc4 and Scc1 in vitro to produce the complex with chain-selective isotopic labeling. Though co-expressed Scc4 and Scc1 form a stable complex, the in vitro association studies suggest that partial protein denaturation and/or components in E. coli lysate are necessary to form the stable complex. In this study Scc4 and Scc1 were sequentially expressed in E. coli under the control of different promoters, allowing separate isotopic labeling of each chain and complex formation in vivo. Sequential expression resulted in no or unstable complex formation depending on the culture medium used. These results, taken together with previous in vitro association studies, suggest that Scc4 and Scc1 assemble co-translationally to form the stable Scc4:Scc1 complex in E. coli.
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Affiliation(s)
| | - Juliette N Lincoln
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, United States
| | - Anne E D'Armond
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, United States
| | - Sadie A Noble
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, United States
| | - Li Shen
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, United States
| | - Megan A Macnaughtan
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, United States; Department of Chemistry and Biochemistry, John Carroll University, University Heights, OH, 44118, United States.
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2
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Pereira IS, da Cunha M, Leal IP, Luís MP, Gonçalves P, Gonçalves C, Mota LJ. Identification of homologs of the Chlamydia trachomatis effector CteG reveals a family of Chlamydiaceae type III secreted proteins that can be delivered into host cells. Med Microbiol Immunol 2024; 213:15. [PMID: 39008129 PMCID: PMC11249467 DOI: 10.1007/s00430-024-00798-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 07/06/2024] [Indexed: 07/16/2024]
Abstract
Chlamydiae are a large group of obligate endosymbionts of eukaryotes that includes the Chlamydiaceae family, comprising several animal pathogens. Among Chlamydiaceae, Chlamydia trachomatis causes widespread ocular and urogenital infections in humans. Like many bacterial pathogens, all Chlamydiae manipulate host cells by injecting them with type III secretion effector proteins. We previously characterized the C. trachomatis effector CteG, which localizes at the host cell Golgi and plasma membrane during distinct phases of the chlamydial infectious cycle. Here, we show that CteG is a Chlamydiaceae-specific effector with over 60 homologs phylogenetically categorized into two distinct clades (CteG I and CteG II) and exhibiting several inparalogs and outparalogs. Notably, cteG I homologs are syntenic to C. trachomatis cteG, whereas cteG II homologs are syntenic among themselves but not with C. trachomatis cteG. This indicates a complex evolution of cteG homologs, which is unique among C. trachomatis effectors, marked by numerous events of gene duplication and loss. Despite relatively modest sequence conservation, nearly all tested CteG I and CteG II proteins were identified as type III secretion substrates using Yersinia as a heterologous bacterial host. Moreover, most of the type III secreted CteG I and CteG II homologs were delivered by C. trachomatis into host cells, where they localized at the Golgi region and cell periphery. Overall, this provided insights into the evolution of bacterial effectors and revealed a Chlamydiaceae family of type III secreted proteins that underwent substantial divergence during evolution while conserving the capacity to localize at specific host cell compartments.
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Affiliation(s)
- Inês Serrano Pereira
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Maria da Cunha
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Inês Pacheco Leal
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Maria Pequito Luís
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Paula Gonçalves
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Carla Gonçalves
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Luís Jaime Mota
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal.
- UCIBIO - Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal.
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3
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Herrera CM, McMahon E, Swaney DL, Sherry J, Pha K, Adams-Boone K, Johnson JR, Krogan NJ, Stevers M, Solomon D, Elwell C, Engel J. The Chlamydia trachomatis Inc Tri1 interacts with TRAF7 to displace native TRAF7 interacting partners. Microbiol Spectr 2024; 12:e0045324. [PMID: 38814079 PMCID: PMC11218536 DOI: 10.1128/spectrum.00453-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/23/2024] [Indexed: 05/31/2024] Open
Abstract
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections in the USA and of preventable blindness worldwide. This obligate intracellular pathogen replicates within a membrane-bound inclusion, but how it acquires nutrients from the host while avoiding detection by the innate immune system is incompletely understood. C. trachomatis accomplishes this in part through the translocation of a unique set of effectors into the inclusion membrane, the inclusion membrane proteins (Incs). Incs are ideally positioned at the host-pathogen interface to reprogram host signaling by redirecting proteins or organelles to the inclusion. Using a combination of co-affinity purification, immunofluorescence confocal imaging, and proteomics, we characterize the interaction between an early-expressed Inc of unknown function, Tri1, and tumor necrosis factor receptor-associated factor 7 (TRAF7). TRAF7 is a multi-domain protein with a RING finger ubiquitin ligase domain and a C-terminal WD40 domain. TRAF7 regulates several innate immune signaling pathways associated with C. trachomatis infection and is mutated in a subset of tumors. We demonstrate that Tri1 and TRAF7 specifically interact during infection and that TRAF7 is recruited to the inclusion. We further show that the predicted coiled-coil domain of Tri1 is necessary to interact with the TRAF7 WD40 domain. Finally, we demonstrate that Tri1 displaces the native TRAF7 binding partners, mitogen-activated protein kinase kinase kinase 2 (MEKK2), and MEKK3. Together, our results suggest that by displacing TRAF7 native binding partners, Tri1 has the capacity to alter TRAF7 signaling during C. trachomatis infection.IMPORTANCEChlamydia trachomatis is the leading cause of bacterial sexually transmitted infections in the USA and preventable blindness worldwide. Although easily treated with antibiotics, the vast majority of infections are asymptomatic and therefore go untreated, leading to infertility and blindness. This obligate intracellular pathogen evades the immune response, which contributes to these outcomes. Here, we characterize the interaction between a C. trachomatis-secreted effector, Tri1, and a host protein involved in innate immune signaling, TRAF7. We identified host proteins that bind to TRAF7 and demonstrated that Tri1 can displace these proteins upon binding to TRAF7. Remarkably, the region of TRAF7 to which these host proteins bind is often mutated in a subset of human tumors. Our work suggests a mechanism by which Tri1 may alter TRAF7 signaling and has implications not only in the pathogenesis of C. trachomatis infections but also in understanding the role of TRAF7 in cancer.
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Affiliation(s)
- Clara M. Herrera
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Eleanor McMahon
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Danielle L. Swaney
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA
| | - Jessica Sherry
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Khavong Pha
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Kathleen Adams-Boone
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Jeffrey R. Johnson
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA
| | - Nevan J. Krogan
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, USA
| | - Meredith Stevers
- Department of Pathology, University of California San Francisco, San Francisco, California, USA
| | - David Solomon
- Department of Pathology, University of California San Francisco, San Francisco, California, USA
| | - Cherilyn Elwell
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Joanne Engel
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, USA
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Steiert B, Andersen SE, McCaslin PN, Elwell CA, Faris R, Tijerina X, Smith P, Eldridge Q, Imai BS, Arrington JV, Yau PM, Mirrashidi KM, Johnson JR, Verschueren E, Von Dollen J, Jang GM, Krogan NJ, Engel JN, Weber MM. Global mapping of the Chlamydia trachomatis conventional secreted effector - host interactome reveals CebN interacts with nucleoporins and Rae1 to impede STAT1 nuclear translocation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.587017. [PMID: 38712050 PMCID: PMC11071493 DOI: 10.1101/2024.04.25.587017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Chlamydia trachomatis ( C.t .), the leading cause of bacterial sexually transmitted infections, employs a type III secretion system (T3SS) to translocate two classes of effectors, inclusion membrane proteins and conventional T3SS (cT3SS) effectors, into the host cell to counter host defense mechanisms. Here we employed three assays to directly evaluate secretion during infection, validating secretion for 23 cT3SS effectors. As bioinformatic analyses have been largely unrevealing, we conducted affinity purification-mass spectrometry to identify host targets and gain insights into the functions of these effectors, identifying high confidence interacting partners for 21 cT3SS effectors. We demonstrate that CebN localizes to the nuclear envelope in infected and bystander cells where it interacts with multiple nucleoporins and Rae1, blocking STAT1 nuclear import following IFN-γ stimulation. By building a cT3SS effector-host interactome, we have identified novel pathways that are targeted during bacterial infection and have begun to address how C.t. effectors combat cell autonomous immunity.
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5
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Wurihan W, Wang Y, Yeung S, Zou Y, Lai Z, Fondell JD, Li WV, Zhong G, Fan H. Expression activation of over 70% of Chlamydia trachomatis genes during the first hour of infection. Infect Immun 2024; 92:e0053923. [PMID: 38299827 PMCID: PMC10929459 DOI: 10.1128/iai.00539-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 01/09/2024] [Indexed: 02/02/2024] Open
Abstract
The obligate intracellular bacterium Chlamydia has a unique developmental cycle that alternates between two contrasting cell types. With a hardy envelope and highly condensed genome, the small elementary body (EB) maintains limited metabolic activities yet survives in extracellular environments and is infectious. After entering host cells, EBs differentiate into larger and proliferating reticulate bodies (RBs). Progeny EBs are derived from RBs in late developmental stages and eventually exit host cells. How expression of the chlamydial genome consisting of nearly 1,000 genes governs the chlamydial developmental cycle is unclear. A previous microarray study identified only 29 Chlamydia trachomatis immediate early genes, defined as genes with increased expression during the first hour postinoculation in cultured cells. In this study, we performed more sensitive RNA sequencing (RNA-Seq) analysis for C. trachomatis cultures with high multiplicities of infection. Remarkably, we observed well over 700 C. trachomatis genes that underwent 2- to 900-fold activation within 1 hour postinoculation. Quantitative reverse transcription real-time PCR analysis was further used to validate the activated expression of a large subset of the genes identified by RNA-Seq. Importantly, our results demonstrate that the immediate early transcriptome is over 20 times more extensive than previously realized. Gene ontology analysis indicates that the activated expression spans all functional categories. We conclude that over 70% of C. trachomatis genes are activated in EBs almost immediately upon entry into host cells, thus implicating their importance in initiating rapid differentiation into RBs and establishing an intracellular niche conducive with chlamydial development and growth.
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Affiliation(s)
- Wurihan Wurihan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, China
| | - Yuxuan Wang
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Sydney Yeung
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Yi Zou
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Zhao Lai
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, Texas, USA
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Joseph D. Fondell
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Wei Vivian Li
- Department of Statistics, University of California Riverside, Riverside, California, USA
| | - Guangming Zhong
- Department of Microbiology and Immunology, University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Huizhou Fan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
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6
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Herrera CM, McMahon E, Swaney DL, Sherry J, Pha K, Adams-Boone K, Johnson JR, Krogan NJ, Stevers M, Solomon D, Elwell C, Engel J. The Chlamydia trachomatis Inc Tri1 interacts with TRAF7 to displace native TRAF7 interacting partners. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.581999. [PMID: 38464023 PMCID: PMC10925117 DOI: 10.1101/2024.02.26.581999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections in the US and of preventable blindness worldwide. This obligate intracellular pathogen replicates within a membrane-bound inclusion, but how it acquires nutrients from the host while avoiding detection by the innate immune system is incompletely understood. C. trachomatis accomplishes this in part through the translocation of a unique set of effectors into the inclusion membrane, the inc lusion membrane proteins (Incs). Incs are ideally positioned at the host-pathogen interface to reprogram host signaling by redirecting proteins or organelles to the inclusion. Using a combination of co-affinity purification, immunofluorescence confocal imaging, and proteomics, we characterize the interaction between an early-expressed Inc of unknown function, Tri1, and tumor necrosis factor receptor associated factor 7 (TRAF7). TRAF7 is a multi-domain protein with a RING finger ubiquitin ligase domain and a C-terminal WD40 domain. TRAF7 regulates several innate immune signaling pathways associated with C. trachomatis infection and is mutated in a subset of tumors. We demonstrate that Tri1 and TRAF7 specifically interact during infection and that TRAF7 is recruited to the inclusion. We further show that the predicted coiled-coil domain of Tri1 is necessary to interact with the TRAF7 WD40 domain. Finally, we demonstrate that Tri1 displaces the native TRAF7 binding partners, mitogen activated protein kinase kinase kinase 2 (MEKK2) and MEKK3. Together, our results suggest that by displacing TRAF7 native binding partners, Tri1 has the capacity to alter TRAF7 signaling during C. trachomatis infection. Importance Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections in the US and preventable blindness worldwide. Although easily treated with antibiotics, the vast majority of infections are asymptomatic and therefore go untreated, leading to infertility and blindness. This obligate intracellular pathogen evades the immune response, which contributes to these outcomes. Here, we characterize the interaction between a C. trachomatis secreted effector, Tri1, and a host protein involved in innate immune signaling, TRAF7. We identified host proteins that bind to TRAF7 and demonstrate that Tri1 can displace these proteins upon binding to TRAF7. Remarkably, the region of TRAF7 to which these host proteins bind is often mutated in a subset of human tumors. Our work suggests a mechanism by which Tri1 may alter TRAF7 signaling and has implications not only in the pathogenesis of C. trachomatis infections, but also in understanding the role of TRAF7 in cancer.
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7
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Bastidas RJ, Kędzior M, Davidson RK, Walsh SC, Dolat L, Sixt BS, Pruneda JN, Coers J, Valdivia RH. The acetylase activity of Cdu1 regulates bacterial exit from infected cells by protecting Chlamydia effectors from degradation. eLife 2024; 12:RP87386. [PMID: 38358795 PMCID: PMC10942603 DOI: 10.7554/elife.87386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Many cellular processes are regulated by ubiquitin-mediated proteasomal degradation. Pathogens can regulate eukaryotic proteolysis through the delivery of proteins with de-ubiquitinating (DUB) activities. The obligate intracellular pathogen Chlamydia trachomatis secretes Cdu1 (ChlaDUB1), a dual deubiquitinase and Lys-acetyltransferase, that promotes Golgi remodeling and survival of infected host cells presumably by regulating the ubiquitination of host and bacterial proteins. Here, we determined that Cdu1's acetylase but not its DUB activity is important to protect Cdu1 from ubiquitin-mediated degradation. We further identified three C. trachomatis proteins on the pathogen-containing vacuole (InaC, IpaM, and CTL0480) that required Cdu1's acetylase activity for protection from degradation and determined that Cdu1 and these Cdu1-protected proteins are required for optimal egress of Chlamydia from host cells. These findings highlight a non-canonical mechanism of pathogen-mediated protection of virulence factors from degradation after their delivery into host cells and the coordinated regulation of secreted effector proteins.
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Affiliation(s)
- Robert J Bastidas
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
| | - Mateusz Kędzior
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
| | - Robert K Davidson
- Department of Molecular Genetics and Microbiology, Duke UniversityDukeUnited States
| | - Stephen C Walsh
- Department of Molecular Genetics and Microbiology, Duke UniversityDukeUnited States
| | - Lee Dolat
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
| | - Barbara S Sixt
- Deparment of Molecular Biology, Umeå UniversityUmeåSweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå UniversityUmeåSweden
- Umeå Centre for Microbial Research (UCMR), Umeå UniversityUmeåSweden
| | - Jonathan N Pruneda
- Department of Molecular Microbiology & Immunology, Oregon Health & Science UniversityPortlandUnited States
| | - Jorn Coers
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
- Department of Molecular Genetics and Microbiology, Duke UniversityDukeUnited States
| | - Raphael H Valdivia
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
- Department of Molecular Genetics and Microbiology, Duke UniversityDukeUnited States
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Walker FC, Derré I. Contributions of diverse models of the female reproductive tract to the study of Chlamydia trachomatis-host interactions. Curr Opin Microbiol 2024; 77:102416. [PMID: 38103413 PMCID: PMC10922760 DOI: 10.1016/j.mib.2023.102416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/19/2023]
Abstract
Chlamydia trachomatis is a common cause of sexually transmitted infections in humans with devastating sequelae. Understanding of disease on all scales, from molecular details to the immunology underlying pathology, is essential for identifying new ways of preventing and treating chlamydia. Infection models of various complexity are essential to understand all aspects of chlamydia pathogenesis. Cell culture systems allow for research into molecular details of infection, including characterization of the unique biphasic Chlamydia developmental cycle and the role of type-III-secreted effectors in modifying the host environment to allow for infection. Multicell type and organoid culture provide means to investigate how cells other than the infected cells contribute to the control of infection. Emerging comprehensive three-dimensional biomimetic systems may fill an important gap in current models to provide information on complex phenotypes that cannot be modeled in simpler in vitro models.
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Affiliation(s)
- Forrest C Walker
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America.
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9
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Wang X, Wu H, Fang C, Li Z. Insights into innate immune cell evasion by Chlamydia trachomatis. Front Immunol 2024; 15:1289644. [PMID: 38333214 PMCID: PMC10850350 DOI: 10.3389/fimmu.2024.1289644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/11/2024] [Indexed: 02/10/2024] Open
Abstract
Chlamydia trachomatis, is a kind of obligate intracellular pathogen. The removal of C. trachomatis relies primarily on specific cellular immunity. It is currently considered that CD4+ Th1 cytokine responses are the major protective immunity against C. trachomatis infection and reinfection rather than CD8+ T cells. The non-specific immunity (innate immunity) also plays an important role in the infection process. To survive inside the cells, the first process that C. trachomatis faces is the innate immune response. As the "sentry" of the body, mast cells attempt to engulf and remove C. trachomatis. Dendritic cells present antigen of C. trachomatis to the "commanders" (T cells) through MHC-I and MHC-II. IFN-γ produced by activated T cells and natural killer cells (NK) further activates macrophages. They form the body's "combat troops" and produce immunity against C. trachomatis in the tissues and blood. In addition, the role of eosinophils, basophils, innate lymphoid cells (ILCs), natural killer T (NKT) cells, γδT cells and B-1 cells should not be underestimated in the infection of C. trachomatis. The protective role of innate immunity is insufficient, and sexually transmitted diseases (STDs) caused by C. trachomatis infections tend to be insidious and recalcitrant. As a consequence, C. trachomatis has developed a unique evasion mechanism that triggers inflammatory immunopathology and acts as a bridge to protective to pathological adaptive immunity. This review focuses on the recent advances in how C. trachomatis evades various innate immune cells, which contributes to vaccine development and our understanding of the pathophysiologic consequences of C. trachomatis infection.
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Affiliation(s)
| | | | | | - Zhongyu Li
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, School of Nursing, Hengyang Medical College, University of South China, Hengyang, China
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10
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Bastidas RJ, Kędzior M, Davidson RK, Walsh SC, Dolat L, Sixt BS, Pruneda JN, Coers J, Valdivia RH. The acetylase activity of Cdu1 regulates bacterial exit from infected cells by protecting Chlamydia effectors from degradation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.28.530337. [PMID: 36909574 PMCID: PMC10002621 DOI: 10.1101/2023.02.28.530337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Many cellular processes are regulated by ubiquitin-mediated proteasomal degradation. Pathogens can regulate eukaryotic proteolysis through the delivery of proteins with de-ubiquitinating (DUB) activities. The obligate intracellular pathogen Chlamydia trachomatis secretes Cdu1 (ChlaDUB1), a dual deubiquitinase and Lys-acetyltransferase, that promotes Golgi remodeling and survival of infected host cells presumably by regulating the ubiquitination of host and bacterial proteins. Here we determined that Cdu1's acetylase but not its DUB activity is important to protect Cdu1 from ubiquitin-mediated degradation. We further identified three C. trachomatis proteins on the pathogen-containing vacuole (InaC, IpaM, and CTL0480) that required Cdu1's acetylase activity for protection from degradation and determined that Cdu1 and these Cdu1-protected proteins are required for optimal egress of Chlamydia from host cells. These findings highlight a non-canonical mechanism of pathogen-mediated protection of virulence factors from degradation after their delivery into host cells and the coordinated regulation of secreted effector proteins.
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Affiliation(s)
- Robert J. Bastidas
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
| | - Mateusz Kędzior
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
| | - Robert K. Davidson
- Department of Molecular Genetics and Microbiology, Duke University, Durham, N.C 27708, USA
| | - Stephen C. Walsh
- Department of Molecular Genetics and Microbiology, Duke University, Durham, N.C 27708, USA
| | - Lee Dolat
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
| | - Barbara S. Sixt
- Deparment of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Jonathan N. Pruneda
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Jörn Coers
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
- Department of Molecular Genetics and Microbiology, Duke University, Durham, N.C 27708, USA
| | - Raphael H. Valdivia
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
- Department of Molecular Genetics and Microbiology, Duke University, Durham, N.C 27708, USA
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11
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Jury B, Fleming C, Huston WM, Luu LDW. Molecular pathogenesis of Chlamydia trachomatis. Front Cell Infect Microbiol 2023; 13:1281823. [PMID: 37920447 PMCID: PMC10619736 DOI: 10.3389/fcimb.2023.1281823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/03/2023] [Indexed: 11/04/2023] Open
Abstract
Chlamydia trachomatis is a strict intracellular human pathogen. It is the main bacterial cause of sexually transmitted infections and the etiologic agent of trachoma, which is the leading cause of preventable blindness. Despite over 100 years since C. trachomatis was first identified, there is still no vaccine. However in recent years, the advancement of genetic manipulation approaches for C. trachomatis has increased our understanding of the molecular pathogenesis of C. trachomatis and progress towards a vaccine. In this mini-review, we aimed to outline the factors related to the developmental cycle phase and specific pathogenesis activity of C. trachomatis in order to focus priorities for future genetic approaches. We highlight the factors known to be critical for developmental cycle stages, gene expression regulatory factors, type III secretion system and their effectors, and individual virulence factors with known impacts.
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Affiliation(s)
- Brittany Jury
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | - Charlotte Fleming
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | | | - Laurence Don Wai Luu
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
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12
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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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13
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Hüsler D, Stauffer P, Hilbi H. Tapping lipid droplets: A rich fat diet of intracellular bacterial pathogens. Mol Microbiol 2023; 120:194-209. [PMID: 37429596 DOI: 10.1111/mmi.15120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/12/2023]
Abstract
Lipid droplets (LDs) are dynamic and versatile organelles present in most eukaryotic cells. LDs consist of a hydrophobic core of neutral lipids, a phospholipid monolayer coat, and a variety of associated proteins. LDs are formed at the endoplasmic reticulum and have diverse roles in lipid storage, energy metabolism, membrane trafficking, and cellular signaling. In addition to their physiological cellular functions, LDs have been implicated in the pathogenesis of several diseases, including metabolic disorders, cancer, and infections. A number of intracellular bacterial pathogens modulate and/or interact with LDs during host cell infection. Members of the genera Mycobacterium, Legionella, Coxiella, Chlamydia, and Salmonella exploit LDs as a source of intracellular nutrients and membrane components to establish their distinct intracellular replicative niches. In this review, we focus on the biogenesis, interactions, and functions of LDs, as well as on their role in lipid metabolism of intracellular bacterial pathogens.
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Affiliation(s)
- Dario Hüsler
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Pia Stauffer
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
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14
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Bastidas RJ, Valdivia RH. The emerging complexity of Chlamydia trachomatis interactions with host cells as revealed by molecular genetic approaches. Curr Opin Microbiol 2023; 74:102330. [PMID: 37247566 PMCID: PMC10988583 DOI: 10.1016/j.mib.2023.102330] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023]
Abstract
Chlamydia trachomatis (Ct) is an intracellular bacterial pathogen that relies on the activity of secreted proteins known as effectors to promote replication and avoidance of immune clearance. Understanding the contribution of Ct effectors to pathogenesis has proven to be challenging, given that these proteins often perform multiple functions during intracellular infection. Recent advances in molecular genetic analysis of Ct have provided valuable insights into the multifaceted nature of secreted effector proteins and their impact on the interaction between Ct and host cells and tissues. This review highlights significant findings from genetic analysis of Ct effector functions, shedding light on their diverse roles. We also discuss the challenges faced in this field of study and explore potential opportunities for further research.
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Affiliation(s)
- Robert J Bastidas
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Raphael H Valdivia
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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15
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Collingro A, Köstlbacher S, Siegl A, Toenshoff ER, Schulz F, Mitchell SO, Weinmaier T, Rattei T, Colquhoun DJ, Horn M. The Fish Pathogen "Candidatus Clavichlamydia salmonicola"-A Missing Link in the Evolution of Chlamydial Pathogens of Humans. Genome Biol Evol 2023; 15:evad147. [PMID: 37615694 PMCID: PMC10448858 DOI: 10.1093/gbe/evad147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2023] [Indexed: 08/25/2023] Open
Abstract
Chlamydiae like Chlamydia trachomatis and Chlamydia psittaci are well-known human and animal pathogens. Yet, the chlamydiae are a much larger group of evolutionary ancient obligate intracellular bacteria that includes predominantly symbionts of protists and diverse animals. This makes them ideal model organisms to study evolutionary transitions from symbionts in microbial eukaryotes to pathogens of humans. To this end, comparative genome analysis has served as an important tool. Genome sequence data for many chlamydial lineages are, however, still lacking, hampering our understanding of their evolutionary history. Here, we determined the first high-quality draft genome sequence of the fish pathogen "Candidatus Clavichlamydia salmonicola", representing a separate genus within the human and animal pathogenic Chlamydiaceae. The "Ca. Clavichlamydia salmonicola" genome harbors genes that so far have been exclusively found in Chlamydia species suggesting that basic mechanisms important for the interaction with chordate hosts have evolved stepwise in the history of chlamydiae. Thus, the genome sequence of "Ca. Clavichlamydia salmonicola" allows to constrain candidate genes to further understand the evolution of chlamydial virulence mechanisms required to infect mammals.
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Affiliation(s)
- Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Stephan Köstlbacher
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Doctoral School in Microbiology and Environmental Science, University of Vienna, Vienna, Austria
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Alexander Siegl
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Elena R Toenshoff
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich (ETH), Zürich, Switzerland
| | - Frederik Schulz
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- DOE Joint Genome Institute, Berkeley, California, USA
| | | | - Thomas Weinmaier
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Thomas Rattei
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | | | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
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16
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McCaslin PN, Andersen SE, Icardi CM, Faris R, Steiert B, Smith P, Haider J, Weber MM. Identification and Preliminary Characterization of Novel Type III Secreted Effector Proteins in Chlamydia trachomatis. Infect Immun 2023; 91:e0049122. [PMID: 37347192 PMCID: PMC10353436 DOI: 10.1128/iai.00491-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 05/28/2023] [Indexed: 06/23/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen that replicates in a host-derived vacuole termed the inclusion. Central to pathogenesis is a type III secretion system that translocates effector proteins into the host cell, which are predicted to play major roles in host cell invasion, nutrient acquisition, and immune evasion. However, until recently, the genetic intractability of C. trachomatis hindered identification and characterization of these important virulence factors. Here, we sought to expand the repertoire of identified effector proteins and confirm they are secreted during C. trachomatis infection. Utilizing bioinformatics, we identified 18 candidate substrates that had not been previously assessed for secretion, of which we show four to be secreted, using Yersinia pseudotuberculosis as a surrogate host. Using adenylate cyclase (CyaA), BlaM, and glycogen synthase kinase (GSK) secretion assays, we identified nine novel substrates that were secreted in at least one assay. Interestingly, only three of the substrates, shown to be translocated by C. trachomatis, were similarly secreted by Y. pseudotuberculosis. Using large-scale screens to determine subcellular localization and identify effectors that perturb crucial host cell processes, we identified one novel substrate, CT392, that is toxic when heterologously expressed in Saccharomyces cerevisiae. Toxicity required both the N- and C-terminal regions of the protein. Additionally, we show that these newly described substrates traffic to distinct host cell compartments, including vesicles and the cytoplasm. Collectively, our study expands the known repertoire of C. trachomatis secreted factors and highlights the importance of testing for secretion in the native host using multiple secretion assays when possible.
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Affiliation(s)
- Paige N. McCaslin
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Shelby E. Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Carolina M. Icardi
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Brianna Steiert
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Parker Smith
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Jawad Haider
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Mary M. Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
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17
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Luu LDW, Kasimov V, Phillips S, Myers GSA, Jelocnik M. Genome organization and genomics in Chlamydia: whole genome sequencing increases understanding of chlamydial virulence, evolution, and phylogeny. Front Cell Infect Microbiol 2023; 13:1178736. [PMID: 37287464 PMCID: PMC10242142 DOI: 10.3389/fcimb.2023.1178736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/10/2023] [Indexed: 06/09/2023] Open
Abstract
The genus Chlamydia contains important obligate intracellular bacterial pathogens to humans and animals, including C. trachomatis and C. pneumoniae. Since 1998, when the first Chlamydia genome was published, our understanding of how these microbes interact, evolved and adapted to different intracellular host environments has been transformed due to the expansion of chlamydial genomes. This review explores the current state of knowledge in Chlamydia genomics and how whole genome sequencing has revolutionised our understanding of Chlamydia virulence, evolution, and phylogeny over the past two and a half decades. This review will also highlight developments in multi-omics and other approaches that have complemented whole genome sequencing to advance knowledge of Chlamydia pathogenesis and future directions for chlamydial genomics.
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Affiliation(s)
- Laurence Don Wai Luu
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
| | - Vasilli Kasimov
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Samuel Phillips
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Garry S. A. Myers
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Sydney, NSW, Australia
| | - Martina Jelocnik
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, QLD, Australia
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18
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Steiert B, Icardi CM, Faris R, McCaslin PN, Smith P, Klingelhutz AJ, Yau PM, Weber MM. The Chlamydia trachomatis type III-secreted effector protein CteG induces centrosome amplification through interactions with centrin-2. Proc Natl Acad Sci U S A 2023; 120:e2303487120. [PMID: 37155906 PMCID: PMC10193975 DOI: 10.1073/pnas.2303487120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 04/11/2023] [Indexed: 05/10/2023] Open
Abstract
The centrosome is the main microtubule organizing center of the cell and is crucial for mitotic spindle assembly, chromosome segregation, and cell division. Centrosome duplication is tightly controlled, yet several pathogens, most notably oncogenic viruses, perturb this process leading to increased centrosome numbers. Infection by the obligate intracellular bacterium Chlamydia trachomatis (C.t.) correlates with blocked cytokinesis, supernumerary centrosomes, and multipolar spindles; however, the mechanisms behind how C.t. induces these cellular abnormalities remain largely unknown. Here we show that the secreted effector protein, CteG, binds to centrin-2 (CETN2), a key structural component of centrosomes and regulator of centriole duplication. Our data indicate that both CteG and CETN2 are necessary for infection-induced centrosome amplification, in a manner that requires the C-terminus of CteG. Strikingly, CteG is important for in vivo infection and growth in primary cervical cells but is dispensable for growth in immortalized cells, highlighting the importance of this effector protein to chlamydial infection. These findings begin to provide mechanistic insight into how C.t. induces cellular abnormalities during infection, but also indicate that obligate intracellular bacteria may contribute to cellular transformation events. Centrosome amplification mediated by CteG-CETN2 interactions may explain why chlamydial infection leads to an increased risk of cervical or ovarian cancer.
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Affiliation(s)
- Brianna Steiert
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA52242
| | - Carolina M. Icardi
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA52242
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA52242
| | - Paige N. McCaslin
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA52242
| | - Parker Smith
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA52242
| | - Aloysius J. Klingelhutz
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA52242
| | - Peter M. Yau
- Carver Biotechnology Center–Protein Sciences Facility, University of Illinois at Urbana–Champaign, Urbana, IL61801
| | - Mary M. Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA52242
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19
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Luís MP, Pereira IS, Bugalhão JN, Simões CN, Mota C, Romão MJ, Mota LJ. The Chlamydia trachomatis IncM Protein Interferes with Host Cell Cytokinesis, Centrosome Positioning, and Golgi Distribution and Contributes to the Stability of the Pathogen-Containing Vacuole. Infect Immun 2023; 91:e0040522. [PMID: 36877064 PMCID: PMC10112248 DOI: 10.1128/iai.00405-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/13/2023] [Indexed: 03/07/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterial pathogen that causes ocular and urogenital infections in humans. The ability of C. trachomatis to grow intracellularly in a pathogen-containing vacuole (known as an inclusion) depends on chlamydial effector proteins transported into the host cell by a type III secretion system. Among these effectors, several inclusion membrane proteins (Incs) insert in the vacuolar membrane. Here, we show that human cell lines infected by a C. trachomatis strain deficient for Inc CT288/CTL0540 (renamed IncM) displayed less multinucleation than when infected by IncM-producing strains (wild type or complemented). This indicated that IncM is involved in the ability of Chlamydia to inhibit host cell cytokinesis. The capacity of IncM to induce multinucleation in infected cells was shown to be conserved among its chlamydial homologues and appeared to require its two larger regions predicted to be exposed to the host cell cytosol. C. trachomatis-infected cells also displayed IncM-dependent defects in centrosome positioning, Golgi distribution around the inclusion, and morphology and stability of the inclusion. The altered morphology of inclusions containing IncM-deficient C. trachomatis was further affected by depolymerization of host cell microtubules. This was not observed after depolymerization of microfilaments, and inclusions containing wild-type C. trachomatis did not alter their morphology upon depolymerization of microtubules. Overall, these findings suggest that IncM may exert its effector function by acting directly or indirectly on host cell microtubules.
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Affiliation(s)
- Maria Pequito Luís
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Inês Serrano Pereira
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Joana N. Bugalhão
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Catarina N. Simões
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | - Cristiano Mota
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Chemistry, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Maria João Romão
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Chemistry, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Luís Jaime Mota
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
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20
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Vormittag S, Ende RJ, Derré I, Hilbi H. Pathogen vacuole membrane contact sites - close encounters of the fifth kind. MICROLIFE 2023; 4:uqad018. [PMID: 37223745 PMCID: PMC10117887 DOI: 10.1093/femsml/uqad018] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/30/2023] [Accepted: 04/06/2023] [Indexed: 05/25/2023]
Abstract
Vesicular trafficking and membrane fusion are well-characterized, versatile, and sophisticated means of 'long range' intracellular protein and lipid delivery. Membrane contact sites (MCS) have been studied in far less detail, but are crucial for 'short range' (10-30 nm) communication between organelles, as well as between pathogen vacuoles and organelles. MCS are specialized in the non-vesicular trafficking of small molecules such as calcium and lipids. Pivotal MCS components important for lipid transfer are the VAP receptor/tether protein, oxysterol binding proteins (OSBPs), the ceramide transport protein CERT, the phosphoinositide phosphatase Sac1, and the lipid phosphatidylinositol 4-phosphate (PtdIns(4)P). In this review, we discuss how these MCS components are subverted by bacterial pathogens and their secreted effector proteins to promote intracellular survival and replication.
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Affiliation(s)
| | | | - Isabelle Derré
- Corresponding author. Department of Microbiology, Immunology and Cancer Biology, University of Virginia, 1340 Jefferson Park Ave, Charlottesville, VA 22908, United States. Tel: +1-434-924-2330; E-mail:
| | - Hubert Hilbi
- Corresponding author. Institute of Medical Microbiology, University of Zürich, Gloriastrasse 30, 8006 Zürich, Switzerland. Tel: +41-44-634-2650; E-mail:
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21
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Homologues of the Chlamydia trachomatis and Chlamydia muridarum Inclusion Membrane Protein IncS Are Interchangeable for Early Development but Not for Inclusion Stability in the Late Developmental Cycle. mSphere 2023; 8:e0000323. [PMID: 36853051 PMCID: PMC10117133 DOI: 10.1128/msphere.00003-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium, which undergoes a biphasic developmental cycle inside a vacuole termed the inclusion. Chlamydia-specific effector proteins embedded into the inclusion membrane, the Inc proteins, facilitate inclusion interaction with cellular organelles. A subset of Inc proteins engages with specific host factors at the endoplasmic reticulum (ER)-inclusion membrane contact site (MCS), which is a discrete point of contact between the inclusion membrane and the endoplasmic reticulum (ER). Here, we report that the C. trachomatis Inc protein CTL0402/IncSCt is a novel component of the ER-inclusion MCS that specifically interacts with and recruits STIM1, a previously identified host component of the ER-inclusion MCS with an unassigned interacting partner at the inclusion membrane. In comparison, the Chlamydia muridarum IncS homologue (TC0424/IncSCm) does not interact with or recruit STIM1 to the inclusion, indicating species specificity. To further investigate IncS function and overcome the recently reported early developmental defect of the incS mutant, we achieved temporal complementation by expressing IncS exclusively during the early stages of the developmental cycle. Additionally, we used allelic exchange to replace the incSCt open reading frame with incSCm in the C. trachomatis chromosome. Inclusions harboring either of these strains progressed through the developmental cycle but were STIM1 negative and displayed increased inclusion lysis 48 h postinfection. Expression of incSCt in trans complemented these phenotypes. Altogether, our results indicate that IncS is necessary and sufficient to recruit STIM1 to C. trachomatis inclusion and that IncS plays an early developmental role conserved in C. trachomatis and C. muridarum and a late role in inclusion stability specific to C. trachomatis. IMPORTANCE Obligate intracellular pathogens strictly rely on the host for replication. Specialized pathogen-encoded effector proteins play a central role in sophisticated mechanisms of host cell manipulation. In Chlamydia, a subset of these effector proteins, the inclusion membrane proteins, are embedded in the membrane of the vacuole in which the bacteria replicate. Chlamydia encodes 50 to 100 putative Inc proteins. Many are conserved among species, including the human and mouse pathogens Chlamydia trachomatis and Chlamydia muridarum, respectively. However, whether the function(s) of Inc proteins is indeed conserved among species is poorly understood. Here, we characterized the function of the Inc protein IncS conserved in C. trachomatis and C. muridarum. Our work reveals that a single effector protein can play multiple functions at various stages of the developmental cycle. However, these functions are not necessarily conserved across species, suggesting a complex evolutionary path among Chlamydia species.
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22
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Zhang S, Funahashi Y, Tanaka S, Okubo T, Thapa J, Nakamura S, Higashi H, Yamaguchi H. Chlamydia trachomatis relies on the scavenger role of aryl hydrocarbon receptor with detyrosinated tubulin for its intracellular growth, but this is impaired by excess indole. Microbes Infect 2023; 25:105097. [PMID: 36608767 DOI: 10.1016/j.micinf.2022.105097] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/29/2022] [Accepted: 12/29/2022] [Indexed: 01/05/2023]
Abstract
Although IFN-γ depletes tryptophan (Trp) as a defense against intracellular Chlamydia trachomatis (Ct) infected to hypoxic vagina, the presence of indole, a precursor of Trp, enables Ct to infect IFN-γ-exposed culture cells. Meanwhile, Trp-derived indole derivatives interact the aryl hydrocarbon receptor (AhR), which is a ligand-dependent transcription factor involved in the cellular homeostasis with tubulin dynamics. Here, the amounts of IFN-γ and indole in cervical swabs with known Ct infection status were measured, and Ct growth in the presence of indole was determined from the perspective of the AhR axis under hypoxia. A positive correlation between the amounts of IFN-γ and indole was found, and both of these amounts were lower in Ct-positive swabs than in Ct-negative ones. Indole as well as other AhR ligands inhibited Ct growth, especially under normoxia. Ct prompted the expression of detyrosinated tubulin (dTTub), but indole inhibited it. Indole did not stimulate the translocation of AhR to nucleus, and it blocked AhR activation in AhR-reporter cells. Ct growth was reduced more effectively under normoxia in AhR-knockdown cells, an effect that was enhanced by indole, which in turn diminished dTTub. Thus, Ct growth relies on the scavenger role of cytosolic AhR responsible for promoting dTTub expression.
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Affiliation(s)
- Saicheng Zhang
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan.
| | - Yuki Funahashi
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan.
| | - Satoho Tanaka
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan.
| | - Torahiko Okubo
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan.
| | - Jeewan Thapa
- Division of Bioresources, International Institute for Zoonosis Control, Hokkaido University, North-20, West-10, Kita-ku, Sapporo 001-0020, Japan.
| | - Shinji Nakamura
- Division of Biomedical Imaging Research, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Division of Ultrastructural Research, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
| | - Hideaki Higashi
- Division of Infection and Immunity, International Institute for Zoonosis Control, Hokkaido University, North-20, West-10, Kita-ku, Sapporo 001-0020, Japan.
| | - Hiroyuki Yamaguchi
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo 060-0812, Japan.
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Scharbaai-Vázquez R, J. López Font F, A. Zayas Rodríguez F. Persistence in Chlamydia. Infect Dis (Lond) 2022. [DOI: 10.5772/intechopen.109299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Chlamydia spp. are important causes of acute and persistent/chronic infections. All Chlamydia spp. display a unique biphasic developmental cycle alternating between an infectious elementary body (EB) and a replicative form, the reticulate body (RB), followed by the multiplication of RBs by binary fission and progressive differentiation back into EBs. During its intracellular life, Chlamydia employs multiple mechanisms to ensure its persistence inside the host. These include evasion of diverse innate immune responses, modulation of host cell structure and endocytosis, inhibition of apoptosis, activation of pro-signaling pathways, and conversion to enlarged, non-replicative but viable “aberrant bodies” (ABs). Early research described several systems for Chlamydial persistence with a significant number of variables that make a direct comparison of results difficult. Now, emerging tools for genetic manipulations in Chlamydia and advances in global microarray, transcriptomics, and proteomics have opened new and exciting opportunities to understand the persistent state of Chlamydia and link the immune and molecular events of persistence with the pathogenesis of recurrent and chronic Chlamydial infections. This chapter reviews our current understanding and advances in the molecular biology of Chlamydia persistence.
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Cortina ME, Bishop RC, DeVasure BA, Coppens I, Derré I. The inclusion membrane protein IncS is critical for initiation of the Chlamydia intracellular developmental cycle. PLoS Pathog 2022; 18:e1010818. [PMID: 36084160 PMCID: PMC9491573 DOI: 10.1371/journal.ppat.1010818] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 09/21/2022] [Accepted: 08/22/2022] [Indexed: 11/18/2022] Open
Abstract
All Chlamydia species are obligate intracellular bacteria that undergo a unique biphasic developmental cycle strictly in the lumen of a membrane bound compartment, the inclusion. Chlamydia specific Type III secreted effectors, known as inclusion membrane proteins (Inc), are embedded into the inclusion membrane. Progression through the developmental cycle, in particular early events of conversion from infectious (EB) to replicative (RB) bacteria, is important for intracellular replication, but poorly understood. Here, we identified the inclusion membrane protein IncS as a critical factor for Chlamydia development. We show that a C. trachomatis conditional mutant is impaired in transition from EB to RB in human cells, and C. muridarum mutant bacteria fail to develop in a mouse model of Chlamydia infection. Thus, IncS represents a promising target for therapeutic intervention of the leading cause of sexually transmitted infections of bacterial origin.
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Affiliation(s)
- María Eugenia Cortina
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - R. Clayton Bishop
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Brittany A. DeVasure
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
- * E-mail:
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25
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Tsujikawa R, Thapa J, Okubo T, Nakamura S, Zhang S, Furuta Y, Higashi H, Yamaguchi H. Chlamydia trachomatis L2/434/Bu Favors Hypoxia for its Growth in Human Lymphoid Jurkat Cells While Maintaining Production of Proinflammatory Cytokines. Curr Microbiol 2022; 79:265. [PMID: 35859064 DOI: 10.1007/s00284-022-02961-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 06/27/2022] [Indexed: 11/03/2022]
Abstract
The role of lymphocytes as a cornerstone of the inflammatory response in the invasive pathogenesis of Chlamydia trachomatis (Ct) LGV (L1-3) infection is unclear. Therefore, we assessed whether the adaptation of CtL2 to immortal lymphoid Jurkat cells under hypoxic conditions occurred through proinflammatory cytokine profile modification. The quantities of inclusion-forming units with chlamydial 16S rDNA confirmed that CtL2 grew well under hypoxic rather than normoxic conditions in the cells. Confocal microscopic imaging and transmission electron microscopy revealed the presence of bacterial progeny in the inclusions and showed that the inclusions were larger under hypoxic rather than normoxic conditions; this was supported by the results of 3D image construction. Furthermore, PCR-based analysis of proinflammatory cytokines revealed that the gene expression levels under hypoxic conditions were significantly higher than those under normoxic conditions. In particular, the expression of two genes (CXCL8 and CXCR3) was significantly diminished under normoxic conditions. Taken together, the results indicated that hypoxia promoted CtL2 growth in Jurkat cells while maintaining the levels of proinflammatory cytokines. Thus, Ct LGV infection in lymphocytes under hypoxic conditions might be crucial to a complete understanding of the invasive pathogenesis.
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Affiliation(s)
- Ryoya Tsujikawa
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Kita 12, Nishi 5, Kitaku, Sapporo, Hokkaido, 060-0812, Japan
| | - Jeewan Thapa
- Division of Bioresources, International Institute for Zoonosis Control, Hokkaido University, North-20, West-10, Kita-ku, Sapporo, 001-0020, Japan
| | - Torahiko Okubo
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Kita 12, Nishi 5, Kitaku, Sapporo, Hokkaido, 060-0812, Japan
| | - Shinji Nakamura
- Division of Biomedical Imaging Research, and Division of Ultrastructural Research, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Saicheng Zhang
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Kita 12, Nishi 5, Kitaku, Sapporo, Hokkaido, 060-0812, Japan
| | - Yoshikazu Furuta
- Division of Infection and Immunity, International Institute for Zoonosis Control, Hokkaido University, North-20, West-10, Kita-ku, Sapporo, 001-0020, Japan
| | - Hideaki Higashi
- Division of Infection and Immunity, International Institute for Zoonosis Control, Hokkaido University, North-20, West-10, Kita-ku, Sapporo, 001-0020, Japan
| | - Hiroyuki Yamaguchi
- Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Kita 12, Nishi 5, Kitaku, Sapporo, Hokkaido, 060-0812, Japan.
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26
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Ende RJ, Murray RL, D'Spain SK, Coppens I, Derré I. Phosphoregulation accommodates Type III secretion and assembly of a tether of ER- Chlamydia inclusion membrane contact sites. eLife 2022; 11:74535. [PMID: 35838228 PMCID: PMC9286742 DOI: 10.7554/elife.74535] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 06/24/2022] [Indexed: 12/20/2022] Open
Abstract
Membrane contact sites (MCS) are crucial for nonvesicular trafficking-based interorganelle communication. Endoplasmic reticulum (ER)-organelle tethering occurs in part through the interaction of the ER resident protein VAP with FFAT motif-containing proteins. FFAT motifs are characterized by a seven amino acidic core surrounded by acid tracks. We have previously shown that the human intracellular bacterial pathogen Chlamydia trachomatis establishes MCS between its vacuole (the inclusion) and the ER through expression of a bacterial tether, IncV, displaying molecular mimicry of eukaryotic FFAT motif cores. Here, we show that multiple layers of host cell kinase-mediated phosphorylation events govern the assembly of the IncV-VAP tethering complex and the formation of ER-Inclusion MCS. Via a C-terminal region containing three CK2 phosphorylation motifs, IncV recruits CK2 to the inclusion leading to IncV hyperphosphorylation of the noncanonical FFAT motif core and serine-rich tracts immediately upstream of IncV FFAT motif cores. Phosphorylatable serine tracts, rather than genetically encoded acidic tracts, accommodate Type III-mediated translocation of IncV to the inclusion membrane, while achieving full mimicry of FFAT motifs. Thus, regulatory components and post-translational modifications are integral to MCS biology, and intracellular pathogens such as C. trachomatis have evolved complex molecular mimicry of these eukaryotic features.
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Affiliation(s)
- Rachel J Ende
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, United States
| | - Rebecca L Murray
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, United States
| | - Samantha K D'Spain
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, United States
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, United States
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, United States
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27
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Pereira IS, Pais SV, Borges V, Borrego MJ, Gomes JP, Mota LJ. The Type III Secretion Effector CteG Mediates Host Cell Lytic Exit of Chlamydia trachomatis. Front Cell Infect Microbiol 2022; 12:902210. [PMID: 35903198 PMCID: PMC9318579 DOI: 10.3389/fcimb.2022.902210] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/25/2022] [Indexed: 11/17/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium causing ocular and urogenital infections in humans that are a significant burden worldwide. The completion of its characteristic infectious cycle relies on the manipulation of several host cell processes by numerous chlamydial type III secretion effector proteins. We previously identified the C. trachomatis CteG effector and showed it localizes at the host cell plasma membrane at late stages of infection. Here, we showed that, from 48 h post-infection, mammalian cells infected by wild-type C. trachomatis contained more infectious chlamydiae in the culture supernatant than cells infected by a CteG-deficient strain. This phenotype was CteG-dependent as it could be complemented in cells infected by the CteG-deficient strain carrying a plasmid encoding CteG. Furthermore, we detected a CteG-dependent defect on host cell cytotoxicity, indicating that CteG mediates chlamydial lytic exit. Previous studies showed that Pgp4, a global regulator of transcription encoded in the C. trachomatis virulence plasmid, also mediates chlamydial lytic exit. However, by using C. trachomatis strains encoding or lacking Pgp4, we showed that production and localization of CteG are not regulated by Pgp4. A C. trachomatis strain lacking both CteG and Pgp4 was as defective in promoting host cell cytotoxicity as mutant strains lacking only CteG or Pgp4. Furthermore, CteG overproduction in a plasmid suppressed the host cell cytotoxic defect of CteG- and Pgp4-deficient chlamydiae. Overall, we revealed the first chlamydial type III secretion effector involved in host cell lytic exit. Our data indicates that CteG and Pgp4 participate in a single cascade of events, but involving multiple layers of regulation, leading to lysis of host cells and release of the infectious chlamydiae.
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Affiliation(s)
- Inês Serrano Pereira
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO – Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Sara Vilela Pais
- UCIBIO – Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Vítor Borges
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge (INSA), Lisbon, Portugal
| | - Maria José Borrego
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge (INSA), Lisbon, Portugal
| | - João Paulo Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge (INSA), Lisbon, Portugal
| | - Luís Jaime Mota
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- UCIBIO – Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- *Correspondence: Luís Jaime Mota,
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The Chlamydia trachomatis Inclusion Membrane Protein CTL0390 Mediates Host Cell Exit via Lysis through STING Activation. Infect Immun 2022; 90:e0019022. [PMID: 35587198 DOI: 10.1128/iai.00190-22] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The obligate intracellular bacterium Chlamydia trachomatis is the causative agent of the most frequently reported bacterial sexually transmitted disease. Upon internalization into host cells, C. trachomatis remains within a membrane-bound compartment known as an inclusion, where it undergoes its developmental cycle. After completion of this cycle, bacteria exit the host cell. One mechanism of exit is lysis, whereby the inclusion and host cell rupture to release bacteria; however, the mechanism of lysis is not well characterized. A subset of C. trachomatis effectors, known as inclusion membrane proteins (Inc), are embedded within the inclusion membrane to facilitate host cell manipulation. The functions of many Inc proteins are unknown. We sought to characterize the Inc protein CTL0390. We determined that CTL0390 is expressed throughout the developmental cycle and that its C-terminal tail is exposed to the cytosol. To investigate the function of CTL0390, we generated a ctl0390 mutant complemented with ctl0390 on a plasmid. Loss of CTL0390 did not affect infectious progeny production but resulted in a reduction in lysis. Overexpression of CTL0390 induced premature lysis and host nuclear condensation, the latter of which could be reduced upon inhibition of the cGAS-STING DNA sensing pathway. Infection with the clt0390 mutant led to reduced Golgi translocation of STING, and chemical and genetic approaches to inactivate STING revealed that STING plays a role in lysis in a CTL0390-dependent manner. Together, these results reveal a role for CTL0390 in bacterial exit via lysis at late stages of the Chlamydia developmental cycle and through STING activation.
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29
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Garvin LE, DeBoer AG, Carrell SJ, Wang X, Rockey DD. Microscopic Analysis of the Chlamydia abortus Inclusion and Its Interaction with Those Formed by Other Chlamydial Species. Infect Immun 2022; 90:e0049921. [PMID: 35099268 PMCID: PMC8929342 DOI: 10.1128/iai.00499-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022] Open
Abstract
The Chlamydiae are obligate intracellular pathogens that develop and multiply within a poorly characterized parasitophorous vacuole (the inclusion) during growth. Chlamydia abortus is a major pathogen of sheep and other ruminants, and its inclusion development is poorly characterized. We used immunofluorescence microscopy, quantitative culture, and qPCR to examine C. abortus inclusion development and to examine the interaction of C. abortus inclusions with those formed by other species. Antibodies used in these studies include sera from ewes from production facilities that were naturally infected with C. abortus. Multiple inclusions are often found in C. abortus-infected cells, even in populations infected at very low multiplicity of infection. Labeling of fixed cells with sera from infected sheep revealed fibrous structures that extend away from the inclusion into the cytoplasm of the host cell. C. abortus inclusions fused with C. caviae and C. psittaci inclusions in coinfected cells. Inclusions formed by C. abortus and C. caviae did not fuse with inclusions formed by C. trachomatis, C. pneumoniae, or C. pecorum. The ability of inclusions to fuse was correlated with the overall genomic relatedness between species, and with sequence similarity in the inclusion membrane protein IncA. Quantitative PCR data demonstrated that C. abortus grows at a decreased rate during coinfections with C. caviae, while C. caviae growth was unaffected. The collected data add depth to our understanding of inclusion development in this significant zoonotic veterinary pathogen.
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Affiliation(s)
- Lotisha E. Garvin
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Addison G. DeBoer
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Steven J. Carrell
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Xisheng Wang
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
| | - Daniel D. Rockey
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
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30
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The Chlamydia trachomatis inclusion membrane protein CT006 associates with lipid droplets in eukaryotic cells. PLoS One 2022; 17:e0264292. [PMID: 35192658 PMCID: PMC8863265 DOI: 10.1371/journal.pone.0264292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/07/2022] [Indexed: 11/19/2022] Open
Abstract
Chlamydia trachomatis causes genital and ocular infections in humans. This bacterial pathogen multiplies exclusively within host cells in a characteristic vacuole (inclusion) and delivers proteins such as inclusion membrane proteins (Incs) into the host cell. Here, we identified CT006 as a novel C. trachomatis protein that when expressed ectopically eukaryotic cells can associate with lipid droplets (LDs). A screen using Saccharomyces cerevisiae identified two Incs causing vacuolar protein sorting defects and seven Incs showing tropism for eukaryotic organelles. Ectopic expression in yeast and mammalian cells of genes encoding different fragments of CT006 revealed tropism for the endoplasmic reticulum and LDs. We identified a LD-targeting region within the first 88 amino acid residues of CT006, and positively charged residues important for this targeting. Comparing with the parental wild-type strain, cells infected by a newly generated C. trachomatis strain overproducing CT006 with a double hemagglutinin tag showed a slight increase in the area occupied by LDs within the inclusion region. However, we could not correlate this effect with the LD-targeting regions within CT006. We further showed that both the amino and carboxy-terminal regions of CT006, flanking the Inc-characteristic bilobed hydrophobic domain, are exposed to the host cell cytosol during C. trachomatis infection, supporting their availability to interact with host cell targets. Altogether, our data suggest that CT006 might participate in the interaction of LDs with C. trachomatis inclusions.
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31
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Huang Y, Wurihan W, Lu B, Zou Y, Wang Y, Weldon K, Fondell JD, Lai Z, Wu X, Fan H. Robust Heat Shock Response in Chlamydia Lacking a Typical Heat Shock Sigma Factor. Front Microbiol 2022; 12:812448. [PMID: 35046926 PMCID: PMC8762339 DOI: 10.3389/fmicb.2021.812448] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/02/2021] [Indexed: 11/13/2022] Open
Abstract
Cells reprogram their transcriptome in response to stress, such as heat shock. In free-living bacteria, the transcriptomic reprogramming is mediated by increased DNA-binding activity of heat shock sigma factors and activation of genes normally repressed by heat-induced transcription factors. In this study, we performed transcriptomic analyses to investigate heat shock response in the obligate intracellular bacterium Chlamydia trachomatis, whose genome encodes only three sigma factors and a single heat-induced transcription factor. Nearly one-third of C. trachomatis genes showed statistically significant (≥1.5-fold) expression changes 30 min after shifting from 37 to 45°C. Notably, chromosomal genes encoding chaperones, energy metabolism enzymes, type III secretion proteins, as well as most plasmid-encoded genes, were differentially upregulated. In contrast, genes with functions in protein synthesis were disproportionately downregulated. These findings suggest that facilitating protein folding, increasing energy production, manipulating host activities, upregulating plasmid-encoded gene expression, and decreasing general protein synthesis helps facilitate C. trachomatis survival under stress. In addition to relieving negative regulation by the heat-inducible transcriptional repressor HrcA, heat shock upregulated the chlamydial primary sigma factor σ66 and an alternative sigma factor σ28. Interestingly, we show for the first time that heat shock downregulates the other alternative sigma factor σ54 in a bacterium. Downregulation of σ54 was accompanied by increased expression of the σ54 RNA polymerase activator AtoC, thus suggesting a unique regulatory mechanism for reestablishing normal expression of select σ54 target genes. Taken together, our findings reveal that C. trachomatis utilizes multiple novel survival strategies to cope with environmental stress and even to replicate. Future strategies that can specifically target and disrupt Chlamydia’s heat shock response will likely be of therapeutic value.
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Affiliation(s)
- Yehong Huang
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Wurihan Wurihan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Bin Lu
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Yi Zou
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Yuxuan Wang
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Korri Weldon
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Joseph D Fondell
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Zhao Lai
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States.,Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Xiang Wu
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China
| | - Huizhou Fan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
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32
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Vaughn B, Abu Kwaik Y. Idiosyncratic Biogenesis of Intracellular Pathogens-Containing Vacuoles. Front Cell Infect Microbiol 2021; 11:722433. [PMID: 34858868 PMCID: PMC8632064 DOI: 10.3389/fcimb.2021.722433] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 10/25/2021] [Indexed: 12/12/2022] Open
Abstract
While most bacterial species taken up by macrophages are degraded through processing of the bacteria-containing vacuole through the endosomal-lysosomal degradation pathway, intravacuolar pathogens have evolved to evade degradation through the endosomal-lysosomal pathway. All intra-vacuolar pathogens possess specialized secretion systems (T3SS-T7SS) that inject effector proteins into the host cell cytosol to modulate myriad of host cell processes and remodel their vacuoles into proliferative niches. Although intravacuolar pathogens utilize similar secretion systems to interfere with their vacuole biogenesis, each pathogen has evolved a unique toolbox of protein effectors injected into the host cell to interact with, and modulate, distinct host cell targets. Thus, intravacuolar pathogens have evolved clear idiosyncrasies in their interference with their vacuole biogenesis to generate a unique intravacuolar niche suitable for their own proliferation. While there has been a quantum leap in our knowledge of modulation of phagosome biogenesis by intravacuolar pathogens, the detailed biochemical and cellular processes affected remain to be deciphered. Here we discuss how the intravacuolar bacterial pathogens Salmonella, Chlamydia, Mycobacteria, Legionella, Brucella, Coxiella, and Anaplasma utilize their unique set of effectors injected into the host cell to interfere with endocytic, exocytic, and ER-to-Golgi vesicle traffic. However, Coxiella is the main exception for a bacterial pathogen that proliferates within the hydrolytic lysosomal compartment, but its T4SS is essential for adaptation and proliferation within the lysosomal-like vacuole.
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Affiliation(s)
- Bethany Vaughn
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, United States
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY, United States.,Center for Predictive Medicine, College of Medicine, University of Louisville, Louisville, KY, United States
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White RT, Legione AR, Taylor-Brown A, Fernandez CM, Higgins DP, Timms P, Jelocnik M. Completing the Genome Sequence of Chlamydia pecorum Strains MC/MarsBar and DBDeUG: New Insights into This Enigmatic Koala ( Phascolarctos cinereus) Pathogen. Pathogens 2021; 10:1543. [PMID: 34959498 PMCID: PMC8703710 DOI: 10.3390/pathogens10121543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/17/2021] [Accepted: 11/24/2021] [Indexed: 12/30/2022] Open
Abstract
Chlamydia pecorum, an obligate intracellular pathogen, causes significant morbidity and mortality in livestock and the koala (Phascolarctos cinereus). A variety of C. pecorum gene-centric molecular studies have revealed important observations about infection dynamics and genetic diversity in both koala and livestock hosts. In contrast to a variety of C. pecorum molecular studies, to date, only four complete and 16 draft genomes have been published. Of those, only five draft genomes are from koalas. Here, using whole-genome sequencing and a comparative genomics approach, we describe the first two complete C. pecorum genomes collected from diseased koalas. A de novo assembly of DBDeUG_2018 and MC/MarsBar_2018 resolved the chromosomes and chlamydial plasmids each as single, circular contigs. Robust phylogenomic analyses indicate biogeographical separation between strains from northern and southern koala populations, and between strains infecting koala and livestock hosts. Comparative genomics between koala strains identified new, unique, and shared loci that accumulate single-nucleotide polymorphisms and separate between northern and southern, and within northern koala strains. Furthermore, we predicted novel type III secretion system effectors. This investigation constitutes a comprehensive genome-wide comparison between C. pecorum from koalas and provides improvements to annotations of a C. pecorum reference genome. These findings lay the foundations for identifying and understanding host specificity and adaptation behind chlamydial infections affecting koalas.
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Affiliation(s)
- Rhys T. White
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, Sunshine Coast, QLD 4557, Australia; (R.T.W.); (A.T.-B.); (P.T.)
| | - Alistair R. Legione
- Asia Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC 3010, Australia;
| | - Alyce Taylor-Brown
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, Sunshine Coast, QLD 4557, Australia; (R.T.W.); (A.T.-B.); (P.T.)
- Parasites and Microbes Programme, Wellcome Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, UK
| | - Cristina M. Fernandez
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia; (C.M.F.); (D.P.H.)
| | - Damien P. Higgins
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia; (C.M.F.); (D.P.H.)
| | - Peter Timms
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, Sunshine Coast, QLD 4557, Australia; (R.T.W.); (A.T.-B.); (P.T.)
| | - Martina Jelocnik
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, Sunshine Coast, QLD 4557, Australia; (R.T.W.); (A.T.-B.); (P.T.)
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A Chlamydial Plasmid-Dependent Secretion System for the Delivery of Virulence Factors to the Host Cytosol. mBio 2021; 12:e0117921. [PMID: 34101486 PMCID: PMC8262877 DOI: 10.1128/mbio.01179-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Chlamydia are obligate intracellular Gram-negative bacteria distinguished by a unique developmental biology confined within a parasitophorous vacuole termed an inclusion. The chlamydial plasmid is a central virulence factor in the pathogenesis of infection. Plasmid gene protein 4 (Pgp4) regulates the expression of plasmid gene protein 3 (Pgp3) and chromosomal glycogen synthase (GlgA), virulence factors secreted from the inclusion to the host cytosol by an unknown mechanism. Here, we identified a plasmid-dependent secretion system for the cytosolic delivery of Pgp3 and GlgA. The secretion system consisted of a segregated population of globular structures originating from midcycle reticulate bodies. Globular structures contained the Pgp4-regulated proteins CT143, CT144, and CT050 in addition to Pgp3 and GlgA. Genetic replacement of Pgp4 with Pgp3 or GlgA negated the formation of globular structures, resulting in retention of Pgp3 and GlgA in chlamydial organisms. The generation of globular structures and secretion of virulence factors occurred independently of type 2 and type 3 secretion systems. Globular structures were enriched with lipopolysaccharide but lacked detectable major outer membrane protein and heat shock protein 60, implicating them as outer membrane vesicles. Thus, we have discovered a novel chlamydial plasmid-dependent secretion system that transports virulence factor cargo from the chlamydial inclusion to the host cytosol.
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35
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A Same-Genus Screening Approach Reveals Novel Effectors and New Possibilities for Investigating Chlamydia Pathogenesis. J Bacteriol 2021; 203:JB.00157-21. [PMID: 33753471 PMCID: PMC8117527 DOI: 10.1128/jb.00157-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Chlamydiae are obligate intracellular pathogens that rely on secreted effector proteins to establish their intracellular niche. In this issue of the Journal of Bacteriology, Yanatori et al describe a screen for C. pneumoniae effectors, performed in C. trachomatis, which identified several new proteins that are translocated during infection (Yanatori, Miura et al. 2021). More broadly, they demonstrate how new genetic approaches in C. trachomatis can be used to characterize the virulence factors of other Chlamydia species.
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36
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Murray SM, McKay PF. Chlamydia trachomatis: Cell biology, immunology and vaccination. Vaccine 2021; 39:2965-2975. [PMID: 33771390 DOI: 10.1016/j.vaccine.2021.03.043] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 02/06/2023]
Abstract
Chlamydia trachomatis is the causative agent of a highly prevalent sexually transmitted bacterial disease and is associated with a number of severe disease complications. Current therapy options are successful at treating disease, but patients are left without protective immunity and do not benefit the majority asymptomatic patients who do not seek treatment. As such, there is a clear need for a broad acting, protective vaccine that can prevent transmission and protect against symptomatic disease presentation. There are three key elements that underlie successful vaccine development: 1) Chlamydia biology and immune-evasion adaptations, 2) the correlates of protection that prevent disease in natural and experimental infection, 3) reflection upon the evidence provided by previous vaccine attempts. In this review, we give an overview of the unique intra-cellular biology of C. trachomatis and give insight into the dynamic combination of adaptations that allow Chlamydia to subvert host immunity and survive within the cell. We explore the current understanding of chlamydial immunity in animal models and in humans and characterise the key immune correlates of protection against infection. We discuss in detail the specific immune interactions involved in protection, with relevance placed on the CD4+ T lymphocyte and B lymphocyte responses that are key to pathogen clearance. Finally, we provide a timeline of C. trachomatis vaccine research to date and evaluate the successes and failures in development so far. With insight from these three key elements of research, we suggest potential solutions for chlamydial vaccine development and promising avenues for further exploration.
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Affiliation(s)
- Sam M Murray
- Department of Infectious Diseases, Imperial College London, Norfolk Place, London W2 1PG, UK.
| | - Paul F McKay
- Department of Infectious Diseases, Imperial College London, Norfolk Place, London W2 1PG, UK.
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37
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Andersen SE, Bulman LM, Steiert B, Faris R, Weber MM. Got mutants? How advances in chlamydial genetics have furthered the study of effector proteins. Pathog Dis 2021; 79:ftaa078. [PMID: 33512479 PMCID: PMC7862739 DOI: 10.1093/femspd/ftaa078] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/17/2020] [Indexed: 02/07/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of infectious blindness and a sexually transmitted infection. All chlamydiae are obligate intracellular bacteria that replicate within a membrane-bound vacuole termed the inclusion. From the confines of the inclusion, the bacteria must interact with many host organelles to acquire key nutrients necessary for replication, all while promoting host cell viability and subverting host defense mechanisms. To achieve these feats, C. trachomatis delivers an arsenal of virulence factors into the eukaryotic cell via a type 3 secretion system (T3SS) that facilitates invasion, manipulation of host vesicular trafficking, subversion of host defense mechanisms and promotes bacteria egress at the conclusion of the developmental cycle. A subset of these proteins intercalate into the inclusion and are thus referred to as inclusion membrane proteins. Whereas others, referred to as conventional T3SS effectors, are released into the host cell where they localize to various eukaryotic organelles or remain in the cytosol. Here, we discuss the functions of T3SS effector proteins with a focus on how advances in chlamydial genetics have facilitated the identification and molecular characterization of these important factors.
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Affiliation(s)
- Shelby E Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Lanci M Bulman
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Brianna Steiert
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Mary M Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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38
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Meyer MD, Ryck JD, Goormachtig S, Van Damme P. Keeping in Touch with Type-III Secretion System Effectors: Mass Spectrometry-Based Proteomics to Study Effector-Host Protein-Protein Interactions. Int J Mol Sci 2020; 21:E6891. [PMID: 32961832 PMCID: PMC7555288 DOI: 10.3390/ijms21186891] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 01/03/2023] Open
Abstract
Manipulation of host cellular processes by translocated bacterial effectors is key to the success of bacterial pathogens and some symbionts. Therefore, a comprehensive understanding of effectors is of critical importance to understand infection biology. It has become increasingly clear that the identification of host protein targets contributes invaluable knowledge to the characterization of effector function during pathogenesis. Recent advances in mapping protein-protein interaction networks by means of mass spectrometry-based interactomics have enabled the identification of host targets at large-scale. In this review, we highlight mass spectrometry-driven proteomics strategies and recent advances to elucidate type-III secretion system effector-host protein-protein interactions. Furthermore, we highlight approaches for defining spatial and temporal effector-host interactions, and discuss possible avenues for studying natively delivered effectors in the context of infection. Overall, the knowledge gained when unravelling effector complexation with host factors will provide novel opportunities to control infectious disease outcomes.
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Affiliation(s)
- Margaux De Meyer
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium; (M.D.M.); (J.D.R.)
- VIB Center for Medical Biotechnology, Technologiepark 75, 9052 Zwijnaarde, Belgium
| | - Joren De Ryck
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium; (M.D.M.); (J.D.R.)
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Zwijnaarde, Belgium;
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052 Zwijnaarde, Belgium
| | - Sofie Goormachtig
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Zwijnaarde, Belgium;
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052 Zwijnaarde, Belgium
| | - Petra Van Damme
- Department of Biochemistry and Microbiology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium; (M.D.M.); (J.D.R.)
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39
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Bishop RC, Boretto M, Rutkowski MR, Vankelecom H, Derré I. Murine Endometrial Organoids to Model Chlamydia Infection. Front Cell Infect Microbiol 2020; 10:416. [PMID: 32923409 PMCID: PMC7456808 DOI: 10.3389/fcimb.2020.00416] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/07/2020] [Indexed: 01/07/2023] Open
Abstract
The obligate intracellular bacterium Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections. Once internalized in host cells, C. trachomatis undergoes a biphasic developmental cycle within a membrane-bound compartment, known as the inclusion. Successful establishment of the intracellular niche relies on bacterial Type III effector proteins, such as Inc proteins. In vitro and in vivo systems have contributed to elucidating the intracellular lifestyle of C. trachomatis, but additional models combining the archetypal environment of infection with the advantages of in vitro systems are needed. Organoids are three-dimensional structures that recapitulate the microanatomy of an organ's epithelial layer, bridging the gap between in vitro and in vivo systems. Organoids are emerging as relevant model systems to study interactions between bacterial pathogens and their hosts. Here, we took advantage of recently developed murine endometrial organoids (EMOs) and present a C. trachomatis-murine EMO infection model system. Confocal microscopy of EMOs infected with fluorescent protein-expressing bacteria revealed that inclusions are formed within the cytosol of epithelial cells. Moreover, infection with a C. trachomatis strain that allows for the tracking of RB to EB transition indicated that the bacteria undergo a full developmental cycle, which was confirmed by harvesting infectious bacteria from infected EMOs. Finally, the inducible gene expression and cellular localization of a Chlamydia Inc protein within infected EMOs further demonstrated that this model is compatible with the study of Type III secreted effectors. Altogether, we describe a novel and relevant system for the study of Chlamydia-host interactions.
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Affiliation(s)
- R Clayton Bishop
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States
| | - Matteo Boretto
- Unit of Stem Cell Research, Cluster of Stem Cell and Developmental Biology, Department of Development and Regenerations, University of Leuven, Leuven, Belgium
| | - Melanie R Rutkowski
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States
| | - Hugo Vankelecom
- Unit of Stem Cell Research, Cluster of Stem Cell and Developmental Biology, Department of Development and Regenerations, University of Leuven, Leuven, Belgium
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States
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Context-Dependent Action of Scc4 Reinforces Control of the Type III Secretion System. J Bacteriol 2020; 202:JB.00132-20. [PMID: 32424009 DOI: 10.1128/jb.00132-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/07/2020] [Indexed: 02/03/2023] Open
Abstract
Chlamydia trachomatis Scc4 (formerly CT663) engages the transcription machinery and the pathogenic type III secretion system (T3SS). Both machines are required for Chlamydia infection. These requirements and the limited ability for genetic manipulation in Chlamydia have hampered dissection of Scc4's contributions. Here, by developing bacterial systems that permit the controlled expression and stable maintenance of Scc4, we assess Scc4's effects on chlamydial growth phenotype, secretion, and the patterns of T3SS gene expression. Expressing Scc4 in Escherichia coli lacking a T3SS injectisome causes a growth defect. This deficiency is rescued by overexpressing the β-subunit of RNA polymerase (RNAP) or by exploiting sigma 70 (σ70) (homologous to chlamydial σ66) mutants that strengthen the interaction between σ70 region 4 and the β-flap, confirming Scc4's distinction as a module of RNAP holoenzyme capable of modulating transcription. Yersinia pestis expressing Scc4 sustains a functional T3SS, through which CopN secretion is boosted by cooption of Scc4 and Scc1. Finally, conditional expression of Scc4 in C. trachomatis results in fast expansion of the Chlamydia-containing vacuole and accelerated chlamydial development, coupled to selective up- or downregulation of gene expression from different T3SS genes. This work reveals, for the first time, the context-dependent action of Scc4 linking it to diverse protein networks in bacteria. It establishes that Scc4, when overexpressed, exerts incredible effects on chlamydial development by reinforcing control of the T3SS.IMPORTANCE The T3SS is a key virulence factor required for C. trachomatis infection. The control of the T3SS has not been well studied in this obligate intracellular pathogen. Here, we show that Scc4 plays a major role for precise control of the pathogenic T3SS at the levels of gene expression and effector secretion through genetically separable protein networks, allowing a fast adaptive mode of C. trachomatis development during infection in human epithelial cells.
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Lin M, Grandinetti G, Hartnell LM, Bliss D, Subramaniam S, Rikihisa Y. Host membrane lipids are trafficked to membranes of intravacuolar bacterium Ehrlichia chaffeensis. Proc Natl Acad Sci U S A 2020; 117:8032-8043. [PMID: 32193339 PMCID: PMC7149431 DOI: 10.1073/pnas.1921619117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Ehrlichia chaffeensis, a cholesterol-rich and cholesterol-dependent obligate intracellular bacterium, partially lacks genes for glycerophospholipid biosynthesis. We found here that E. chaffeensis is dependent on host glycerolipid biosynthesis, as an inhibitor of host long-chain acyl CoA synthetases, key enzymes for glycerolipid biosynthesis, significantly reduced bacterial proliferation. E. chaffeensis cannot synthesize phosphatidylcholine or cholesterol but encodes enzymes for phosphatidylethanolamine (PE) biosynthesis; however, exogenous NBD-phosphatidylcholine, Bodipy-PE, and TopFluor-cholesterol were rapidly trafficked to ehrlichiae in infected cells. DiI (3,3'-dioctadecylindocarbocyanine)-prelabeled host-cell membranes were unidirectionally trafficked to Ehrlichia inclusion and bacterial membranes, but DiI-prelabeled Ehrlichia membranes were not trafficked to host-cell membranes. The trafficking of host-cell membranes to Ehrlichia inclusions was dependent on both host endocytic and autophagic pathways, and bacterial protein synthesis, as the respective inhibitors blocked both infection and trafficking of DiI-labeled host membranes to Ehrlichia In addition, DiI-labeled host-cell membranes were trafficked to autophagosomes induced by the E. chaffeensis type IV secretion system effector Etf-1, which traffic to and fuse with Ehrlichia inclusions. Cryosections of infected cells revealed numerous membranous vesicles inside inclusions, as well as multivesicular bodies docked on the inclusion surface, both of which were immunogold-labeled by a GFP-tagged 2×FYVE protein that binds to phosphatidylinositol 3-phosphate. Focused ion-beam scanning electron microscopy of infected cells validated numerous membranous structures inside bacteria-containing inclusions. Our results support the notion that Ehrlichia inclusions are amphisomes formed through fusion of early endosomes, multivesicular bodies, and early autophagosomes induced by Etf-1, and they provide host-cell glycerophospholipids and cholesterol that are necessary for bacterial proliferation.
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Affiliation(s)
- Mingqun Lin
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210
| | - Giovanna Grandinetti
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Lisa M Hartnell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Donald Bliss
- National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
| | - Sriram Subramaniam
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210;
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Kebbi-Beghdadi C, Pilloux L, Martin V, Greub G. Eukaryotic Cell Permeabilisation to Identify New Putative Chlamydial Type III Secretion System Effectors Secreted within Host Cell Cytoplasm. Microorganisms 2020; 8:microorganisms8030361. [PMID: 32138376 PMCID: PMC7143554 DOI: 10.3390/microorganisms8030361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 02/08/2023] Open
Abstract
Chlamydia trachomatis and Waddlia chondrophila are strict intracellular bacteria belonging to the Chlamydiales order. C. trachomatis is the most frequent bacterial cause of genital and ocular infections whereas W. chondrophila is an opportunistic pathogen associated with adverse pregnancy outcomes and respiratory infections. Being strictly intracellular, these bacteria are engaged in a complex interplay with their hosts to modulate their environment and create optimal conditions for completing their life cycle. For this purpose, they possess several secretion pathways and, in particular, a Type III Secretion System (T3SS) devoted to the delivery of effector proteins in the host cell cytosol. Identifying these effectors is a crucial step in understanding the molecular basis of bacterial pathogenesis. Following incubation of infected cells with perfringolysin O, a pore-forming toxin that binds cholesterol present in plasma membranes, we analysed by mass spectrometry the protein content of the host cell cytoplasm. We identified 13 putative effectors secreted by C. trachomatis and 19 secreted by W. chondrophila. Using Y. enterocolitica as a heterologous expression and secretion system, we confirmed that four of these identified proteins are secreted by the T3SS. Two W. chondrophila T3SS effectors (hypothetical proteins Wcw_0499 and Wcw_1706) were further characterised and demonstrated to be early/mid-cycle effectors. In addition, Wcw_1706 is associated with a tetratricopeptide domain-containing protein homologous to C. trachomatis class II chaperone. Furthermore, we identified a novel C. trachomatis effector, CT460 that localises in the eukaryotic nucleus when ectopically expressed in 293 T cells.
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Affiliation(s)
| | | | | | - Gilbert Greub
- Correspondence: ; Tel.: +41-21-314-4979; Fax: +41-21-314-4060
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