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Scholz J, Holland G, Laue M, Banhart S, Heuer D. Chlamydia-containing spheres are a novel and predominant form of egress by the pathogen Chlamydia psittaci. mBio 2024:e0128824. [PMID: 39041785 DOI: 10.1128/mbio.01288-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Accepted: 06/27/2024] [Indexed: 07/24/2024] Open
Abstract
The egress of intracellular bacteria from host cells and cellular tissues is a critical process during the infection cycle. This process is essential for bacteria to spread inside the host and can influence the outcome of an infection. For the obligate intracellular Gram-negative zoonotic bacterium Chlamydia psittaci, little is known about the mechanisms resulting in bacterial egress from the infected epithelium. Here, we describe and characterize Chlamydia-containing spheres (CCSs), a novel and predominant type of non-lytic egress utilized by Chlamydia spp. CCSs are spherical, low-phase contrast structures surrounded by a phosphatidylserine-exposing membrane with specific barrier functions. They contain infectious progeny and morphologically impaired cellular organelles. CCS formation is a sequential process starting with the proteolytic cleavage of a DEVD tetrapeptide-containing substrate that can be detected inside the chlamydial inclusions, followed by an increase in the intracellular calcium concentration of the infected cell. Subsequently, blebbing of the plasma membrane begins, the inclusion membrane destabilizes, and the proteolytic cleavage of a DEVD-containing substrate increases rapidly within the whole infected cell. Finally, infected, blebbing cells detach and leave the monolayer, thereby forming CCS. This sequence of events is unique for chlamydial CCS formation and fundamentally different from previously described Chlamydia egress pathways. Thus, CCS formation represents a major, previously uncharacterized egress pathway for intracellular pathogens that could be linked to Chlamydia biology in general and might influence the infection outcome in vivo.IMPORTANCEHost cell egress is essential for intracellular pathogens to spread within an organism and for host-to-host transmission. Here, we characterize Chlamydia-containing sphere (CCS) formation as a novel and predominant non-lytic egress pathway of the intracellular pathogens Chlamydia psittaci and Chlamydia trachomatis. CCS formation is fundamentally different from extrusion formation, the previously described non-lytic egress pathway of C. trachomatis. CCS formation is a unique sequential process, including proteolytic activity, followed by an increase in intracellular calcium concentration, inclusion membrane destabilization, plasma membrane blebbing, and the final detachment of a whole phosphatidylserine-exposing former host cell. Thus, CCS formation represents an important and previously uncharacterized egress pathway for intracellular pathogens that could possibly be linked to Chlamydia biology, including host tropism, protection from host cell defense mechanisms, or bacterial pathogenicity.
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Affiliation(s)
- Jana Scholz
- Unit of Sexually Transmitted Bacterial Pathogens and HIV, Robert Koch Institute, Berlin, Germany
| | - Gudrun Holland
- Unit of Advanced Light and Electron Microscopy, Robert Koch Institute, Berlin, Germany
| | - Michael Laue
- Unit of Advanced Light and Electron Microscopy, Robert Koch Institute, Berlin, Germany
| | - Sebastian Banhart
- Unit of Sexually Transmitted Bacterial Pathogens and HIV, Robert Koch Institute, Berlin, Germany
| | - Dagmar Heuer
- Unit of Sexually Transmitted Bacterial Pathogens and HIV, Robert Koch Institute, Berlin, Germany
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2
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Yang S, Zeng J, Yu J, Sun R, Tuo Y, Bai H. Insights into Chlamydia Development and Host Cells Response. Microorganisms 2024; 12:1302. [PMID: 39065071 PMCID: PMC11279054 DOI: 10.3390/microorganisms12071302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/15/2024] [Accepted: 06/23/2024] [Indexed: 07/28/2024] Open
Abstract
Chlamydia infections commonly afflict both humans and animals, resulting in significant morbidity and imposing a substantial socioeconomic burden worldwide. As an obligate intracellular pathogen, Chlamydia interacts with other cell organelles to obtain necessary nutrients and establishes an intracellular niche for the development of a biphasic intracellular cycle. Eventually, the host cells undergo lysis or extrusion, releasing infectious elementary bodies and facilitating the spread of infection. This review provides insights into Chlamydia development and host cell responses, summarizing the latest research on the biphasic developmental cycle, nutrient acquisition, intracellular metabolism, host cell fates following Chlamydia invasion, prevalent diseases associated with Chlamydia infection, treatment options, and vaccine prevention strategies. A comprehensive understanding of these mechanisms will contribute to a deeper comprehension of the intricate equilibrium between Chlamydia within host cells and the progression of human disease.
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Affiliation(s)
| | | | | | | | | | - Hong Bai
- Tianjin Key Laboratory of Cellular and Molecular Immunology (The Educational Ministry of China), Tianjin Institute of Immunology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China; (S.Y.); (J.Z.); (J.Y.); (R.S.); (Y.T.)
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3
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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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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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5
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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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Hakiem OR, Rizvi SMA, Ramirez C, Tan M. Euo is a developmental regulator that represses late genes and activates midcycle genes in Chlamydia trachomatis. mBio 2023; 14:e0046523. [PMID: 37565751 PMCID: PMC10653925 DOI: 10.1128/mbio.00465-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/22/2023] [Indexed: 08/12/2023] Open
Abstract
IMPORTANCE In this study, we developed a correlative approach that combined DNA immunoprecipitation-seq and RNA-seq analyses to define the regulon of the Chlamydia trachomatis transcription factor Euo. We confirmed the proposed role of Euo as a transcriptional repressor of late chlamydial genes but also showed that Euo activates transcription of a subset of midcycle genes and autoregulates its own expression via negative feedback. This study validates and expands the role of Euo as an important developmental regulator in C. trachomatis. In addition, this genome-wide correlative approach can be applied to study transcription factors in other pathogenic bacteria.
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Affiliation(s)
- Owais R. Hakiem
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
| | - Syed M. A. Rizvi
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
| | - Cuper Ramirez
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, California, USA
| | - Ming Tan
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, USA
- Department of Medicine, University of California Irvine, Irvine, California, USA
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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. 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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8
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Stuckey PV, Santiago-Tirado FH. Fungal mechanisms of intracellular survival: what can we learn from bacterial pathogens? Infect Immun 2023; 91:e0043422. [PMID: 37506189 PMCID: PMC10501222 DOI: 10.1128/iai.00434-22] [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: 11/28/2022] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
Fungal infections represent a major, albeit neglected, public health threat with serious medical and economic burdens globally. With unacceptably high mortality rates, invasive fungal pathogens are responsible for millions of deaths each year, with a steadily increasing incidence primarily in immunocompromised individuals. The poor therapeutic options and rise of antifungal drug resistance pose further challenges in controlling these infections. These fungal pathogens have adapted to survive within mammalian hosts and can establish intracellular niches to promote survival within host immune cells. To do that, they have developed diverse methods to circumvent the innate immune system attack. This includes strategies such as altering their morphology, counteracting macrophage antimicrobial action, and metabolic adaptation. This is reminiscent of how bacterial pathogens have adapted to survive within host cells and cause disease. However, relative to the great deal of information available concerning intracellular bacterial pathogenesis, less is known about the mechanisms fungal pathogens employ. Therefore, here we review our current knowledge and recent advances in our understanding of how fungi can evade and persist within host immune cells. This review will focus on the major fungal pathogens, including Cryptococcus neoformans, Candida albicans, and Aspergillus fumigatus, among others. As we discover and understand the strategies used by these fungi, similarities with their bacterial counterparts are becoming apparent, hence we can use the abundant information from bacteria to guide our studies in fungi. By understanding these strategies, new lines of research will open that can improve the treatments of these devastating fungal diseases.
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Affiliation(s)
- Peter V. Stuckey
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Felipe H. Santiago-Tirado
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
- Warren Center for Drug Discovery, University of Notre Dame, Notre Dame, Indiana, USA
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9
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Meier K, Jachmann LH, Türköz G, Babu Sait MR, Pérez L, Kepp O, Valdivia RH, Kroemer G, Sixt BS. The Chlamydia effector CpoS modulates the inclusion microenvironment and restricts the interferon response by acting on Rab35. mBio 2023; 14:e0319022. [PMID: 37530528 PMCID: PMC10470785 DOI: 10.1128/mbio.03190-22] [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: 05/15/2023] [Accepted: 06/13/2023] [Indexed: 08/03/2023] Open
Abstract
The obligate intracellular bacterium Chlamydia trachomatis inserts a family of inclusion membrane (Inc) proteins into the membrane of its vacuole (the inclusion). The Inc CpoS is a critical suppressor of host cellular immune surveillance, but the underlying mechanism remained elusive. By complementing a cpoS mutant with various natural orthologs and variants of CpoS, we linked distinct molecular interactions of CpoS to distinct functions. Unexpectedly, we found CpoS to be essential for the formation of inclusion membrane microdomains that control the spatial organization of multiple Incs involved in signaling and modulation of the host cellular cytoskeleton. While the function of CpoS in microdomains was uncoupled from its role in the suppression of host cellular defenses, we found the ability of CpoS to interact with Rab GTPases to be required not only for the manipulation of membrane trafficking, such as to mediate transport of ceramide-derived lipids (sphingolipids) to the inclusion, but also for the inhibition of Stimulator of interferon genes (STING)-dependent type I interferon responses. Indeed, depletion of Rab35 phenocopied the exacerbated interferon responses observed during infection with CpoS-deficient mutants. Overall, our findings highlight the role of Inc-Inc interactions in shaping the inclusion microenvironment and the modulation of membrane trafficking as a pathogenic immune evasion strategy. IMPORTANCE Chlamydia trachomatis is a prevalent bacterial pathogen that causes blinding ocular scarring and urogenital infections that can lead to infertility and pregnancy complications. Because Chlamydia can only grow within its host cell, boosting the intrinsic defenses of human cells may represent a novel strategy to fight pathogen replication and survival. Hence, CpoS, a Chlamydia protein known to block host cellular defenses, or processes regulated by CpoS, could provide new opportunities for therapeutic intervention. By revealing CpoS as a multifunctional virulence factor and by linking its ability to block host cellular immune signaling to the modulation of membrane trafficking, the present work may provide a foundation for such rationale targeting and advances our understanding of how intracellular bacteria can shape and protect their growth niche.
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Affiliation(s)
- Karsten Meier
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Lana H. Jachmann
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Gözde Türköz
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Mohammed Rizwan Babu Sait
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Lucía Pérez
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Oliver Kepp
- Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris, France
| | - Raphael H. Valdivia
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Guido Kroemer
- Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris, France
- Department of Biology, Institut du Cancer Paris CARPEM, Hôpital Européen Georges-Pompidou, AP-HP, Paris, France
| | - Barbara S. Sixt
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
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10
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Turman BJ, Darville T, O'Connell CM. Plasmid-mediated virulence in Chlamydia. Front Cell Infect Microbiol 2023; 13:1251135. [PMID: 37662000 PMCID: PMC10469868 DOI: 10.3389/fcimb.2023.1251135] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 07/31/2023] [Indexed: 09/05/2023] Open
Abstract
Chlamydia trachomatis infection of ocular conjunctiva can lead to blindness, while infection of the female genital tract can lead to chronic pelvic pain, ectopic pregnancy, and/or infertility. Conjunctival and fallopian tube inflammation and the resulting disease sequelae are attributed to immune responses induced by chlamydial infection at these mucosal sites. The conserved chlamydial plasmid has been implicated in enhancing infection, via improved host cell entry and exit, and accelerating innate inflammatory responses that lead to tissue damage. The chlamydial plasmid encodes eight open reading frames, three of which have been associated with virulence: a secreted protein, Pgp3, and putative transcriptional regulators, Pgp4 and Pgp5. Although Pgp3 is an important plasmid-encoded virulence factor, recent studies suggest that chlamydial plasmid-mediated virulence extends beyond the expression of Pgp3. In this review, we discuss studies of genital, ocular, and gastrointestinal infection with C. trachomatis or C. muridarum that shed light on the role of the plasmid in disease development, and the potential for tissue and species-specific differences in plasmid-mediated pathogenesis. We also review evidence that plasmid-associated inflammation can be independent of bacterial burden. The functions of each of the plasmid-encoded proteins and potential molecular mechanisms for their role(s) in chlamydial virulence are discussed. Although the understanding of plasmid-associated virulence has expanded within the last decade, many questions related to how and to what extent the plasmid influences chlamydial infectivity and inflammation remain unknown, particularly with respect to human infections. Elucidating the answers to these questions could improve our understanding of how chlamydia augment infection and inflammation to cause disease.
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Affiliation(s)
- Breanna J. Turman
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, United States
| | - Toni Darville
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, United States
- Department of Pediatrics, University of North Carolina, Chapel Hill, NC, United States
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11
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Clemente TM, Angara RK, Gilk SD. Establishing the intracellular niche of obligate intracellular vacuolar pathogens. Front Cell Infect Microbiol 2023; 13:1206037. [PMID: 37645379 PMCID: PMC10461009 DOI: 10.3389/fcimb.2023.1206037] [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: 04/14/2023] [Accepted: 07/21/2023] [Indexed: 08/31/2023] Open
Abstract
Obligate intracellular pathogens occupy one of two niches - free in the host cell cytoplasm or confined in a membrane-bound vacuole. Pathogens occupying membrane-bound vacuoles are sequestered from the innate immune system and have an extra layer of protection from antimicrobial drugs. However, this lifestyle presents several challenges. First, the bacteria must obtain membrane or membrane components to support vacuole expansion and provide space for the increasing bacteria numbers during the log phase of replication. Second, the vacuole microenvironment must be suitable for the unique metabolic needs of the pathogen. Third, as most obligate intracellular bacterial pathogens have undergone genomic reduction and are not capable of full metabolic independence, the bacteria must have mechanisms to obtain essential nutrients and resources from the host cell. Finally, because they are separated from the host cell by the vacuole membrane, the bacteria must possess mechanisms to manipulate the host cell, typically through a specialized secretion system which crosses the vacuole membrane. While there are common themes, each bacterial pathogen utilizes unique approach to establishing and maintaining their intracellular niches. In this review, we focus on the vacuole-bound intracellular niches of Anaplasma phagocytophilum, Ehrlichia chaffeensis, Chlamydia trachomatis, and Coxiella burnetii.
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Affiliation(s)
| | | | - Stacey D. Gilk
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
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12
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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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13
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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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14
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Scanlon KR, Keb G, Wolf K, Jewett TJ, Fields KA. Chlamydia trachomatis TmeB antagonizes actin polymerization via direct interference with Arp2/3 activity. Front Cell Infect Microbiol 2023; 13:1232391. [PMID: 37483386 PMCID: PMC10360934 DOI: 10.3389/fcimb.2023.1232391] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/26/2023] [Indexed: 07/25/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen that actively promotes invasion of epithelial cells. A virulence-associated type III secretion system contributes to chlamydial entry and at least four effectors have been described that are deployed during this time. Two of these invasion-related effectors, the translocated membrane-associated effectors A and B (TmeA and TmeB), are encoded in a bi-cistronic operon. TmeA directly activates host N-WASP to stimulate Arp2/3-dependent actin polymerization. According to current working models, TmeA-mediated N-WASP activation contributes to invasion. TmeB has not been functionally characterized. Unlike a tmeA null strain, loss of tmeB does not impact invasion efficiency of C. trachomatis. Using strains deficient for multiple genes, we provide evidence that TmeA is dispensable for invasion in the absence of TmeB. Our data indicate that overabundance of TmeB interferes with invasion and that this activity requires active Arp2/3 complex. We further show that TmeB is capable of interfering with Arp2/3-mediated actin polymerization. In aggregate, these data point to opposing functions for TmeA and TmeB that manifest during the invasion process. These studies raise intriguing questions regarding the dynamic interplay between TmeA, TmeB, and branched actin polymerization during chlamydial entry.
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Affiliation(s)
- Kaylyn R. Scanlon
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Gabrielle Keb
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Katerina Wolf
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Travis J. Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Kenneth A. Fields
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
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15
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Fisher DJ, Beare PA. Recent advances in genetic systems in obligate intracellular human-pathogenic bacteria. Front Cell Infect Microbiol 2023; 13:1202245. [PMID: 37404720 PMCID: PMC10315504 DOI: 10.3389/fcimb.2023.1202245] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/22/2023] [Indexed: 07/06/2023] Open
Abstract
The ability to genetically manipulate a pathogen is fundamental to discovering factors governing host-pathogen interactions at the molecular level and is critical for devising treatment and prevention strategies. While the genetic "toolbox" for many important bacterial pathogens is extensive, approaches for modifying obligate intracellular bacterial pathogens were classically limited due in part to the uniqueness of their obligatory lifestyles. Many researchers have confronted these challenges over the past two and a half decades leading to the development of multiple approaches to construct plasmid-bearing recombinant strains and chromosomal gene inactivation and deletion mutants, along with gene-silencing methods enabling the study of essential genes. This review will highlight seminal genetic achievements and recent developments (past 5 years) for Anaplasma spp., Rickettsia spp., Chlamydia spp., and Coxiella burnetii including progress being made for the still intractable Orientia tsutsugamushi. Alongside commentary of the strengths and weaknesses of the various approaches, future research directions will be discussed to include methods for C. burnetii that should have utility in the other obligate intracellular bacteria. Collectively, the future appears bright for unraveling the molecular pathogenic mechanisms of these significant pathogens.
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Affiliation(s)
- Derek J. Fisher
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, United States
| | - Paul A. Beare
- Rocky Mountain Laboratory, National Institute of Health, Hamilton, MT, United States
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16
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Swoboda AR, Wood NA, Saery EA, Fisher DJ, Ouellette SP. The Periplasmic Tail-Specific Protease, Tsp, Is Essential for Secondary Differentiation in Chlamydia trachomatis. J Bacteriol 2023; 205:e0009923. [PMID: 37092988 PMCID: PMC10210983 DOI: 10.1128/jb.00099-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/03/2023] [Indexed: 04/25/2023] Open
Abstract
The obligate intracellular human pathogen Chlamydia trachomatis (Ctr) undergoes a complex developmental cycle in which the bacterium differentiates between two functionally and morphologically distinct forms: the elementary body (EB) and the reticulate body (RB). The EB is the smaller, infectious, nondividing form which initiates infection of a susceptible host cell, whereas the RB is the larger, non-infectious form which replicates within a membrane-bound vesicle called an inclusion. The mechanism(s) which drives differentiation between these developmental forms is poorly understood. Bulk protein turnover is likely required for chlamydial differentiation given the significant differences in the protein repertoires and functions of the EB and RB. We hypothesize that periplasmic protein turnover is also critical for the reorganization of an RB into an EB, referred to as secondary differentiation. Ct441 is a periplasmic protease ortholog of tail-specific proteases (i.e., Tsp, Prc) and is expressed in Ctr during secondary differentiation. We investigated the effect of altering Tsp expression on developmental cycle progression. Through assessment of bacterial morphology and infectious progeny production, we found that both overexpression and CRISPR interference/dCas9 (CRISPRi)-mediated knockdown of Tsp negatively impacted chlamydial development through different mechanisms. We also confirmed that catalytic activity is required for the negative effect of overexpression and confirmed the effect of the mutation in in vitro assays. Electron microscopic assessments during knockdown experiments revealed a defect in EB morphology, directly linking Tsp function to secondary differentiation. These data implicate Ct441/Tsp as a critical factor in secondary differentiation. IMPORTANCE The human pathogen Chlamydia trachomatis is the leading cause of preventable infectious blindness and bacterial sexually transmitted infections worldwide. This pathogen has a unique developmental cycle that alternates between distinct forms. However, the key processes of chlamydial development remain obscure. Uncovering the mechanisms of differentiation between its metabolically and functionally distinct developmental forms may foster the discovery of novel Chlamydia-specific therapeutics and limit development of resistant bacterial populations derived from the clinical use of broad-spectrum antibiotics. In this study, we investigate chlamydial tail-specific protease (Tsp) and its function in chlamydial growth and development. Our work implicates Tsp as essential to chlamydial developmental cycle progression and indicates that Tsp is a potential drug target for Chlamydia infections.
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Affiliation(s)
- Abigail R. Swoboda
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Nicholas A. Wood
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Elizabeth A. Saery
- School of Biological Sciences, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Derek J. Fisher
- School of Biological Sciences, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Scot P. Ouellette
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
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17
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Wevers C, Höhler M, Alcázar-Román AR, Hegemann JH, Fleig U. A Functional Yeast-Based Screen Identifies the Host Microtubule Cytoskeleton as a Target of Numerous Chlamydia pneumoniae Proteins. Int J Mol Sci 2023; 24:ijms24087618. [PMID: 37108781 PMCID: PMC10142024 DOI: 10.3390/ijms24087618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Bacterial pathogens have evolved intricate ways to manipulate the host to support infection. Here, we systematically assessed the importance of the microtubule cytoskeleton for infection by Chlamydiae, which are obligate intracellular bacteria that are of great importance for human health. The elimination of microtubules in human HEp-2 cells prior to C. pneumoniae infection profoundly attenuated the infection efficiency, demonstrating the need for microtubules for the early infection processes. To identify microtubule-modulating C. pneumoniae proteins, a screen in the model yeast Schizosaccharomyces pombe was performed. Unexpectedly, among 116 selected chlamydial proteins, more than 10%, namely, 13 proteins, massively altered the yeast interphase microtubule cytoskeleton. With two exceptions, these proteins were predicted to be inclusion membrane proteins. As proof of principle, we selected the conserved CPn0443 protein, which caused massive microtubule instability in yeast, for further analysis. CPn0443 bound and bundled microtubules in vitro and co-localized partially with microtubules in vivo in yeast and human cells. Furthermore, CPn0443-transfected U2OS cells had a significantly reduced infection rate by C. pneumoniae EBs. Thus, our yeast screen identified numerous proteins encoded using the highly reduced C. pneumoniae genome that modulated microtubule dynamics. Hijacking of the host microtubule cytoskeleton must be a vital part of chlamydial infection.
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Affiliation(s)
- Carolin Wevers
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Mona Höhler
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Abel R Alcázar-Román
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Johannes H Hegemann
- Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Ursula Fleig
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
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18
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Huang Y, Li S, He S, Li Y, He Q, Wu Y. Chlamydia psittaci inclusion membrane protein CPSIT_0842 induces macrophage apoptosis through MAPK/ERK-mediated autophagy. Int J Biochem Cell Biol 2023; 157:106376. [PMID: 36716815 DOI: 10.1016/j.biocel.2023.106376] [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: 06/01/2022] [Revised: 12/20/2022] [Accepted: 01/26/2023] [Indexed: 01/29/2023]
Abstract
Chlamydia psittaci is a multi-host zoonotic pathogen, which mainly infects poultry and inflicts an appreciable economic burden on the livestock farming industry. C. psittaci inclusion membrane proteins are uniquely positioned at the host-pathogen interface and are important virulence proteins. We have previously confirmed that Incs regulate host cell survival to help Chlamydia sp. evade host-cell-mediated defense mechanisms. However, the role of the Inc, CPSIT_0842, in the regulation of cell death following the establishment of persistent C. psittaci infection remains unknown. This study explored the effect of CPSIT_0842 on the crosstalk between the autophagic and apoptotic pathways in macrophages. Results showed that CPSIT_0842 initiated autophagy and blocked autophagic flux in human macrophages, as indicated by autophagy-related protein LC3-II, Beclin-1, and p62 upregulation, autophagosome accumulation, and lysosomal protein LAMP1 diminution. We also showed that the disruption of autophagic flux had a regulatory effect on CPSIT_0842-induced apoptosis. Moreover, the suppression of autophagy initiation by 3-methyladenine attenuated CPSIT_0842-induced apoptosis. By contrast, the induction of autophagic flux by rapamycin did not significantly affect CPSIT_0842-induced apoptosis. Taken together, these findings demonstrate that CPSIT_0842 induced macrophage apoptosis by initiating incomplete autophagy through the MAPK/ERK/mTOR signaling pathway, which may be instrumental to the ability of C. psittaci to evade the host innate immune response and establish persistent infection. The improved understanding of the autophagic and cell death pathways triggered upon bacterial inclusion will likely help in the development of novel treatment strategies for chlamydia infection.
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Affiliation(s)
- Yanru Huang
- Institute of Pathogenic Biology, Hengyang Medical School, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang 421001, Hunan, China
| | - Sijia Li
- Institute of Pathogenic Biology, Hengyang Medical School, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang 421001, Hunan, China
| | - Siqin He
- Institute of Pathogenic Biology, Hengyang Medical School, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang 421001, Hunan, China
| | - Yumeng Li
- Institute of Pathogenic Biology, Hengyang Medical School, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang 421001, Hunan, China; Department of Clinical Laboratory, The First Affiliated Hospital of University of South China, Hengyang 421000, Hunan, China
| | - Qingzhi He
- School of Biotechnology, Guilin Medical University, Guilin 541199, China
| | - Yimou Wu
- Institute of Pathogenic Biology, Hengyang Medical School, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang 421001, Hunan, China.
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19
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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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20
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Cheng A, Wan D, Ghatak A, Wang C, Feng D, Fondell JD, Ebright RH, Fan H. Identification and Structural Modeling of the RNA Polymerase Omega Subunits in Chlamydiae and Other Obligate Intracellular Bacteria. mBio 2023; 14:e0349922. [PMID: 36719197 PMCID: PMC9973325 DOI: 10.1128/mbio.03499-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 01/04/2023] [Indexed: 02/01/2023] Open
Abstract
Gene transcription in bacteria is carried out by the multisubunit RNA polymerase (RNAP), which is composed of a catalytic core enzyme and a promoter-recognizing σ factor. The core enzyme comprises two α subunits, one β subunit, one β' subunit, and one ω subunit. The ω subunit plays critical roles in the assembly of the core enzyme and other cellular functions, including the regulation of bacterial growth, the stress response, and biofilm formation. However, the identity of an ω subunit for the obligate intracellular bacterium Chlamydia has not previously been determined. Here, we report the identification of the hypothetical protein CTL0286 as the probable chlamydial ω subunit based on sequence, synteny, and AlphaFold and AlphaFold-Multimer three-dimensional-structure predictions. Our findings indicate that CTL0286 functions as the missing ω subunit of chlamydial RNAP. Our extended analysis also indicates that all obligate intracellular bacteria have ω orthologs. IMPORTANCE Chlamydiae are obligate intracellular bacteria that replicate only inside eukaryotic cells. Previously, it has not been possible to identify a candidate gene encoding the chlamydial RNA polymerase ω subunit, and it has been hypothesized that the chlamydial RNA polymerase ω subunit was lost in the evolutionary process through which Chlamydiae reduced their genome size and proteome sizes to adapt to an obligate intracellular lifestyle. Here, we report the identification of the chlamydial RNA polymerase ω subunit, based on conserved sequence, conserved synteny, AlphaFold-predicted conserved three-dimensional structure, and AlfaFold-Multimer-predicted conserved interactions. Our identification of the previously elusive chlamydial RNA polymerase ω subunit sets the stage for investigation of its roles in regulation of gene expression during chlamydial growth, development, and stress responses, and sets the stage for preparation and study of the intact chlamydial RNA polymerase and its interactions with inhibitors.
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Affiliation(s)
- Andrew Cheng
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Danny Wan
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
- Graduate Program in Physiology and Integrative Biology, Rutgers School of Graduate Studies, Piscataway, New Jersey, USA
| | - Arkaprabha Ghatak
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Chengyuan Wang
- Center for Microbes, Development and Health, CAS Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Deyu Feng
- Center for Microbes, Development and Health, CAS Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Joseph D. Fondell
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Richard H. Ebright
- Waksman Institute, Rutgers University, Piscataway, New Jersey, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Huizhou Fan
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
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21
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In Search of a Mechanistic Link between Chlamydia trachomatis-Induced Cellular Pathophysiology and Oncogenesis. Infect Immun 2023; 91:e0044322. [PMID: 36695575 PMCID: PMC9933725 DOI: 10.1128/iai.00443-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Centrosome duplication and cell cycle progression are essential cellular processes that must be tightly controlled to ensure cellular integrity. Despite their complex regulatory mechanisms, microbial pathogens have evolved sophisticated strategies to co-opt these processes to promote infection. While misregulation of these processes can greatly benefit the pathogen, the consequences to the host cell can be devastating. During infection, the obligate intracellular pathogen Chlamydia trachomatis induces gross cellular abnormalities, including supernumerary centrosomes, multipolar spindles, and defects in cytokinesis. While these observations were made over 15 years ago, identification of the bacterial factors responsible has been elusive due to the genetic intractability of Chlamydia. Recent advances in techniques of genetic manipulation now allows for the direct linking of bacterial virulence factors to manipulation of centrosome duplication and cell cycle progression. In this review, we discuss the impact, both immediate and downstream, of C. trachomatis infection on the host cell cycle regulatory apparatus and centrosome replication. We highlight links between C. trachomatis infection and cervical and ovarian cancers and speculate whether perturbations of the cell cycle and centrosome are sufficient to initiate cellular transformation. We also explore the biological mechanisms employed by Inc proteins and other secreted effector proteins implicated in the perturbation of these host cell pathways. Future work is needed to better understand the nuances of each effector's mechanism and their collective impact on Chlamydia's ability to induce host cellular abnormalities.
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22
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Tryptophan Availability during Persistence of Chlamydia trachomatis Directly Impacts Expression of Chlamydial Cell Division Proteins. Infect Immun 2023; 91:e0051322. [PMID: 36645295 PMCID: PMC9933654 DOI: 10.1128/iai.00513-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Chlamydia is an obligate intracellular pathogen with a highly reduced genome devoid of major stress response genes like relA and spoT, which mediate the stringent response. Interestingly, as an intracellular bacterium dependent on its host for nutrients and as a tryptophan (Trp) auxotroph, Chlamydia is very sensitive to Trp starvation, which is induced in vivo by the host cytokine interferon-γ. In response to Trp starvation, Chlamydia enters a viable but nonreplicating state called persistence. A major characteristic of chlamydial persistence is a block in cell division. We hypothesized that cell division is blocked during persistence by the inability to translate Trp-rich cell division proteins. To test this, we first investigated the translation of various cell division proteins under Trp starvation conditions using inducible expression strains. We observed that the Trp-poor protein MurG and the Trp-neutral protein FtsL were still expressed during persistence, while the expression of the Trp-rich proteins Pbp2, RodA, FtsI/Pbp3, and MraY was significantly reduced. As proof of concept for our hypothesis, we compared expression of a wild-type and mutant isoform of RodZ in which its four Trp codons were mutated. These experiments demonstrated that decreased expression of RodZ during persistence was reversed when no Trp was present in the protein, thus directly linking its expression to its Trp content. Together, these experiments indicate that specific cell division proteins are not produced during persistence. For the first time, our data provide a mechanism that explains the inhibition of cell division during chlamydial persistence mediated by Trp starvation.
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23
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Virulence Protein Pgp3 Is Insufficient To Mediate Plasmid-Dependent Infectivity of Chlamydia trachomatis. Infect Immun 2023; 91:e0039222. [PMID: 36722979 PMCID: PMC9933628 DOI: 10.1128/iai.00392-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Chlamydia trachomatis is the most common cause of infectious blindness and sexually transmitted bacterial infection globally. C. trachomatis contains a conserved chlamydial plasmid with eight coding sequences. Plasmid-cured Chlamydia strains are attenuated and display reduced infectivity in cell culture and in vivo genital infection of female mice. Mutants that do not express the plasmid-encoded proteins Pgp3, a secreted protein with unknown function, or Pgp4, a putative regulator of pgp3 and other chromosomal loci, display an infectivity defect similar to plasmid-deficient strains. Our objective was to determine the combined and individual contributions of Pgp3 and Pgp4 to this phenotype. Deletion of pgp3 and pgp4 resulted in an infectivity defect detected by competition assay in cell culture and in mice. The pgp3 locus was placed under the control of an anhydrotetracycline-inducible promoter to examine the individual contributions of Pgp3 and Pgp4 to infectivity. Expression of pgp3 was induced 100- to 1,000-fold after anhydrotetracycline administration, regardless of the presence or absence of pgp4. However, secreted Pgp3 was not detected when pgp4 was deleted, confirming a role for Pgp4 in Pgp3 secretion. We discovered that expression of pgp3 or pgp4 alone was insufficient to restore normal infectivity, which required expression of both Pgp3 and Pgp4. These results suggest Pgp3 and Pgp4 are both required for infectivity during C. trachomatis infection. Future studies are required to determine the mechanism by which Pgp3 and Pgp4 influence chlamydial infectivity as well as the potential roles of Pgp4-regulated loci.
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Intracellular lifestyle of Chlamydia trachomatis and host-pathogen interactions. Nat Rev Microbiol 2023:10.1038/s41579-023-00860-y. [PMID: 36788308 DOI: 10.1038/s41579-023-00860-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2023] [Indexed: 02/16/2023]
Abstract
In recent years, substantial progress has been made in the understanding of the intracellular lifestyle of Chlamydia trachomatis and how the bacteria establish themselves in the human host. As an obligate intracellular pathogenic bacterium with a strongly reduced coding capacity, C. trachomatis depends on the provision of nutrients from the host cell. In this Review, we summarize the current understanding of how C. trachomatis establishes its intracellular replication niche, how its metabolism functions in the host cell, how it can defend itself against the cell autonomous and innate immune response and how it overcomes adverse situations through the transition to a persistent state. In particular, we focus on those processes for which a mechanistic understanding has been achieved.
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de Campos LJ, Seleem MA, Feng J, Pires de Oliveira KM, de Andrade Dos Santos JV, Hayer S, Clayton JB, Kathi S, Fisher DJ, Ouellette SP, Conda-Sheridan M. Design, Biological Evaluation, and Computer-Aided Analysis of Dihydrothiazepines as Selective Antichlamydial Agents. J Med Chem 2023; 66:2116-2142. [PMID: 36696579 PMCID: PMC10056257 DOI: 10.1021/acs.jmedchem.2c01894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Chlamydia trachomatis (CT) causes the most prevalent sexually transmitted bacterial disease in the United States. The lack of drug selectivity is one of the main challenges of the current antichlamydial pharmacotherapy. The metabolic needs of CT are controlled, among others, by cylindrical proteases and their chaperones (e.g., ClpX). It has been shown that dihydrothiazepines can disrupt CT-ClpXP. Based on this precedent, we synthesized a dihydrothiazepine library and characterized its antichlamydial activity using a modified semi-high-throughput screening assay. Then, we demonstrated their ability to inhibit ClpX ATPase activity in vitro, supporting ClpX as a target. Further, our lead compound displayed a promising selectivity profile against CT, acceptable cytotoxicity, no mutagenic potential, and good in vitro stability. A two-dimensional quantitative structure-activity relationship (2D QSAR) model was generated as a support tool in the identification of more potent antichlamydial molecules. This study suggests dihydrothiazepines are a promising starting point for the development of new and selective antichlamydial drugs.
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Affiliation(s)
- Luana Janaína de Campos
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Mohamed A Seleem
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Jiachen Feng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Kelly Mari Pires de Oliveira
- Faculty of Biological and Environmental Science, Federal University of Grande Dourados, Dourados, MS 79804-970, Brazil
| | | | - Shivdeep Hayer
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska 68182, United States
| | - Jonathan B Clayton
- Department of Biology, University of Nebraska at Omaha, Omaha, Nebraska 68182, United States
- Department of Food Science and Technology, University of Nebraska─Lincoln, Lincoln, Nebraska 68588, United States
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
- Nebraska Food for Health Center, University of Nebraska─Lincoln, Lincoln, Nebraska 68508, United States
| | - Sharvath Kathi
- School of Biological Sciences, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Derek J Fisher
- School of Biological Sciences, Southern Illinois University, Carbondale, Illinois 62901, United States
| | - Scot P Ouellette
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Martin Conda-Sheridan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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Stein RA, Thompson LM. Epigenetic changes induced by pathogenic Chlamydia spp. Pathog Dis 2023; 81:ftad034. [PMID: 38031337 DOI: 10.1093/femspd/ftad034] [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: 06/15/2023] [Revised: 11/16/2023] [Accepted: 11/28/2023] [Indexed: 12/01/2023] Open
Abstract
Chlamydia trachomatis, C. pneumoniae, and C. psittaci, the three Chlamydia species known to cause human disease, have been collectively linked to several pathologies, including conjunctivitis, trachoma, respiratory disease, acute and chronic urogenital infections and their complications, and psittacosis. In vitro, animal, and human studies also established additional correlations, such as between C. pneumoniae and atherosclerosis and between C. trachomatis and ovarian cancer. As part of their survival and pathogenesis strategies as obligate intracellular bacteria, Chlamydia spp. modulate all three major types of epigenetic changes, which include deoxyribonucleic acid (DNA) methylation, histone post-translational modifications, and microRNA-mediated gene silencing. Some of these epigenetic changes may be implicated in key aspects of pathogenesis, such as the ability of the Chlamydia spp. to induce epithelial-to-mesenchymal transition, interfere with DNA damage repair, suppress cholesterol efflux from infected macrophages, act as a co-factor in human papillomavirus (HPV)-mediated cervical cancer, prevent apoptosis, and preserve the integrity of mitochondrial networks in infected host cells. A better understanding of the individual and collective contribution of epigenetic changes to pathogenesis will enhance our knowledge about the biology of Chlamydia spp. and facilitate the development of novel therapies and biomarkers. Pathogenic Chlamydia spp. contribute to epigenetically-mediated gene expression changes in host cells by multiple mechanisms.
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Affiliation(s)
- Richard A Stein
- NYU Tandon School of Engineering, Department of Chemical and Biomolecular Engineering, 6 MetroTech Center, Brooklyn, NY 11201, United States
| | - Lily M Thompson
- NYU Tandon School of Engineering, Department of Chemical and Biomolecular Engineering, 6 MetroTech Center, Brooklyn, NY 11201, United States
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Karanovic U, Lei L, Martens CA, Barbian K, McClarty G, Caldwell HD, Yang C. TargeTron inactivation of plasmid-regulated Chlamydia trachomatis CT084 results in a nonlytic phenotype. Pathog Dis 2023; 81:ftad026. [PMID: 37804183 PMCID: PMC10589100 DOI: 10.1093/femspd/ftad026] [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: 06/26/2023] [Revised: 09/07/2023] [Accepted: 10/05/2023] [Indexed: 10/09/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium that causes blinding trachoma and sexually transmitted disease. The chlamydial plasmid is a critical virulence factor in the pathogenesis of these diseases. Plasmid gene protein 4 (Pgp4) plays a major role in chlamydial virulence by regulating the expression of both chromosomal genes and Pgp3. Despite the importance of Pgp4 in mediating lytic exit from host cells the pathogenic mechanism by which it functions is unknown. CT084 is a highly conserved chromosomal gene with homology to phospholipase D. We showed CT084 expression is regulated by Pgp4 and expressed late in the chlamydial developmental cycle. To investigate the function of CT084 in chlamydial lytic exit from infected cells, we made a CT084 null strain (ct084::bla) by using Targetron. The ct084::bla strain grew normally in vitro compared to wild-type strain; however, the strain did not lyse infected cells and produced significantly less and smaller plaques. Collectively, our finding shows Pgp4-regulated CT084-mediated chlamydia lytic exit from infected host cells.
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Affiliation(s)
- Una Karanovic
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, 208952, United States
| | - Lei Lei
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, 208952, United States
| | - Craig A Martens
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, 59840, United States
| | - Kent Barbian
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, 59840, United States
| | - Grant McClarty
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Harlan D Caldwell
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, 208952, United States
| | - Chunfu Yang
- School of Public Health and Emergency Management, Southern University of Science and Technology, Shenzhen 518055, China
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Jahnke R, Matthiesen S, Zaeck LM, Finke S, Knittler MR. Chlamydia trachomatis Cell-to-Cell Spread through Tunneling Nanotubes. Microbiol Spectr 2022; 10:e0281722. [PMID: 36219107 PMCID: PMC9769577 DOI: 10.1128/spectrum.02817-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/16/2022] [Indexed: 01/09/2023] Open
Abstract
Tunneling nanotubes (TNTs) are transient cellular connections that consist of dynamic membrane protrusions. They play an important role in cell-to-cell communication and mediate the intercellular exchanges of molecules and organelles. TNTs can form between different cell types and may contribute to the spread of pathogens by serving as cytoplasmic corridors. We demonstrate that Chlamydia (C.) trachomatis-infected human embryonic kidney (HEK) 293 cells and other cells form TNT-like structures through which reticulate bodies (RBs) pass into uninfected cells. Observed TNTs have a life span of 1 to 5 h and contain microtubules, which are essential for chlamydial transfer. They can bridge distances of up to 50 μm between connecting neighboring cells. Consistent with the biological role for TNTs, we show that C. trachomatis spread also occurs under conditions in which the extracellular route of chlamydial entry into host cells is blocked. Based on our findings, we propose that TNTs play a critical role in the direct, cell-to-cell transmission of chlamydia. IMPORTANCE Intracellular bacterial pathogens often undergo a life cycle in which they parasitize infected host cells in membranous vacuoles. Two pathways have been described by which chlamydia can exit infected host cells: lytic cell destruction or exit via extrusion formation. Whether direct, cell-to-cell contact may also play a role in the spread of infection is unknown. Tunneling nanotubes (TNTs) interconnect the cytoplasm of adjacent cells to mediate efficient communication and the exchange of material between them. We used Chlamydia trachomatis and immortalized cells to analyze whether TNTs mediate bacterial transmission from an infected donor to uninfected acceptor cells. We show that chlamydia-infected cells build TNTs through which the intracellular reticulate bodies (RBs) of the chlamydia can pass into uninfected neighboring cells. Our study contributes to the understanding of the function of TNTs in the cell-to-cell transmission of intracellular pathogens and provides new insights into the strategies by which chlamydia spreads among multicellular tissues.
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Affiliation(s)
- Rico Jahnke
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
| | - Svea Matthiesen
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
| | - Luca M. Zaeck
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
| | - Stefan Finke
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
| | - Michael R. Knittler
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute of Animal Health, Greifswald, Germany
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Goyal N, Barai A, Sen S, Kondabagil K. Amoebal Tubulin Cleavage Late during Infection Is a Characteristic Feature of Mimivirus but Not of Marseillevirus. Microbiol Spectr 2022; 10:e0275322. [PMID: 36453900 PMCID: PMC9769910 DOI: 10.1128/spectrum.02753-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/04/2022] [Indexed: 12/03/2022] Open
Abstract
Mimivirus and Marseillevirus infections of Acanthamoeba castellanii, like most other viral infections, induce cytopathic effects (CPE). The details of how they bring about CPE and to what extent and how they modify the host cytoskeletal network are unclear. In this study, we compared the rearrangement of the host cytoskeletal network induced by Mimivirus and Marseillevirus upon infection. We show that while both Mimivirus and Marseillevirus infections of A. castellanii cells cause retraction of acanthopodia and depolymerization of the host actin filament network, the Mimivirus infection also results in characteristic cleavage of the host tubulin, a phenomenon not previously reported with any intracellular pathogens. Furthermore, we show that the amoebal tubulin cleavage during Mimivirus infection is a post-replicative event. Because time-lapse microscopy showed that Mimivirus infection leads to the bursting of cells, releasing the virus, we hypothesize that tubulin cleavage together with actin depolymerization during the later stages of Mimivirus assembly is essential for cell lysis due to apoptotic/necrotic cell death. We also characterize the Mimivirus-encoded gp560, a Zn metalloprotease, however, the purified gp560 protein was unable to cleave the commercially available porcine brain tubulin. While protein synthesis is essential for causing the morphological changes in the case of Mimivirus, the proteins which are packaged in the viral capsid along with the genome are sufficient to induce CPE in the case of Marseillevirus. IMPORTANCE In general, intracellular pathogens target the cytoskeletal network to enable their life cycle inside the host. Pathogen-induced changes in the host cell morphology usually accompany global changes in the cytoskeleton resulting in cytopathic effects. While viruses have been shown to use the host actin cytoskeleton for entry and transport during early infection, the role of microtubules in the viral life cycle is only beginning to emerge. Here, we show that the giant viruses Mimivirus and Marseillevirus both induce depolymerization of the actin filament, Mimivirus also causes a characteristic cleavage of tubulin not previously reported for any intracellular pathogen. Because tubulin cleavage occurs late during infection, we hypothesize that tubulin cleavage aids in cell death and lysis rather than establishing infection. The different strategies used by viruses with similar host niches may help them survive in competition.
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Affiliation(s)
- Nisha Goyal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Amlan Barai
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Shamik Sen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Kiran Kondabagil
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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30
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Fields KA, Bodero MD, Scanlon KR, Jewett TJ, Wolf K. A Minimal Replicon Enables Efficacious, Species-Specific Gene Deletion in Chlamydia and Extension of Gene Knockout Studies to the Animal Model of Infection Using Chlamydia muridarum. Infect Immun 2022; 90:e0045322. [PMID: 36350146 PMCID: PMC9753632 DOI: 10.1128/iai.00453-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/04/2022] [Indexed: 11/11/2022] Open
Abstract
The genus Chlamydia consists of diverse, obligate intracellular bacteria that infect various animals, including humans. Although chlamydial species share many aspects of the typical intracellular lifestyle, such as the biphasic developmental cycle and the preference for invasion of epithelial cells, each chlamydial strain also employs sophisticated species-specific strategies that contribute to an extraordinary diversity in organ and/or tissue tropism and disease manifestation. In order to discover and understand the mechanisms underlying how these pathogens infect particular hosts and cause specific diseases, it is imperative to develop a mutagenesis approach that would be applicable to every chlamydial species. We present functional evidence that the region between Chlamydia trachomatis and Chlamydia muridarum pgp6 and pgp7, containing four 22-bp tandem repeats that are present in all chlamydial endogenous plasmids, represents the plasmid origin of replication. Furthermore, by introducing species-specific ori regions into an engineered 5.45-kb pUC19-based plasmid, we generated vectors that can be successfully transformed into and propagated under selective pressure by C. trachomatis serovars L2 and D, as well as C. muridarum. Conversely, these vectors were rapidly lost upon removal of the selective antibiotic. This conditionally replicating system was used to generate a tarP deletion mutant by fluorescence-reported allelic exchange mutagenesis in both C. trachomatis serovar D and C. muridarum. The strains were analyzed using in vitro invasion and fitness assays. The virulence of the C. muridarum strains was then assessed in a murine infection model. Our approach represents a novel and efficient strategy for targeted genetic manipulation in Chlamydia beyond C. trachomatis L2. This advance will support comparative studies of species-specific infection biology and enable studies in a well-established murine model of chlamydial pathogenesis.
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Affiliation(s)
- Kenneth A. Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Maria D. Bodero
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Kaylyn R. Scanlon
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Travis J. Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Katerina Wolf
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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31
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Dolat L, Carpenter VK, Chen YS, Suzuki M, Smith EP, Kuddar O, Valdivia RH. Chlamydia repurposes the actin-binding protein EPS8 to disassemble epithelial tight junctions and promote infection. Cell Host Microbe 2022; 30:1685-1700.e10. [PMID: 36395759 PMCID: PMC9793342 DOI: 10.1016/j.chom.2022.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 08/08/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022]
Abstract
Invasive microbial pathogens often disrupt epithelial barriers, yet the mechanisms used to dismantle tight junctions are poorly understood. Here, we show that the obligate pathogen Chlamydia trachomatis uses the effector protein TepP to transiently disassemble tight junctions early during infection. TepP alters the tyrosine phosphorylation status of host proteins involved in cytoskeletal regulation, including the filamentous actin-binding protein EPS8. We determined that TepP and EPS8 are necessary and sufficient to remodel tight junctions and that the ensuing disruption of epithelial barrier function promotes secondary invasion events. The genetic deletion of EPS8 renders epithelial cells and endometrial organoids resistant to TepP-mediated tight junction remodeling. Finally, TepP and EPS8 promote infection in murine models of infections, with TepP mutants displaying defects in ascension to the upper genital tract. These findings reveal a non-canonical function of EPS8 in the disassembly of epithelial junctions and an important role for Chlamydia pathogenesis.
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Affiliation(s)
- Lee Dolat
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Victoria K Carpenter
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Yi-Shan Chen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michitaka Suzuki
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Erin P Smith
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ozge Kuddar
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Raphael H Valdivia
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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Chlamydia trachomatis suppresses host cell store-operated Ca 2+ entry and inhibits NFAT/calcineurin signaling. Sci Rep 2022; 12:21406. [PMID: 36496532 PMCID: PMC9741641 DOI: 10.1038/s41598-022-25786-y] [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: 04/29/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
The obligate intracellular bacterium, Chlamydia trachomatis, replicates within a parasitophorous vacuole termed an inclusion. During development, host proteins critical for regulating intracellular calcium (Ca2+) homeostasis interact with the inclusion membrane. The inclusion membrane protein, MrcA, interacts with the inositol-trisphosphate receptor (IP3R), an ER cationic channel that conducts Ca2+. Stromal interaction molecule 1 (STIM1), an ER transmembrane protein important for regulating store-operated Ca2+ entry (SOCE), localizes to the inclusion membrane via an uncharacterized interaction. We therefore examined Ca2+ mobilization in C. trachomatis infected cells. Utilizing a variety of Ca2+ indicators to assess changes in cytosolic Ca2+ concentration, we demonstrate that C. trachomatis impairs host cell SOCE. Ca2+ regulates many cellular signaling pathways. We find that the SOCE-dependent NFAT/calcineurin signaling pathway is impaired in C. trachomatis infected HeLa cells and likely has major implications on host cell physiology as it relates to C. trachomatis pathogenesis.
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Kuwabara S, Landers ER, Fisher DJ. Impact of nutrients on the function of the chlamydial Rsb partner switching mechanism. Pathog Dis 2022; 80:6831632. [PMID: 36385643 DOI: 10.1093/femspd/ftac044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/27/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022] Open
Abstract
The obligate intracellular bacterial pathogen Chlamydia trachomatis is a leading cause of sexually transmitted infections and infectious blindness. Chlamydia undergo a biphasic developmental cycle alternating between the infectious elementary body (EB) and the replicative reticulate body (RB). The molecular mechanisms governing RB growth and RB-EB differentiation are unclear. We hypothesize that the bacterium senses host cell and bacterial energy levels and metabolites to ensure that development and growth coincide with nutrient availability. We predict that a partner switching mechanism (PSM) plays a key role in the sensing and response process acting as a molecular throttle sensitive to metabolite levels. Using purified wild type and mutant PSM proteins, we discovered that metal type impacts enzyme activity and the substrate specificity of RsbU and that RsbW prefers ATP over GTP as a phosphate donor. Immunoblotting analysis of RsbV1/V2 demonstrated the presence of both proteins beyond 20 hours post infection and we observed that an RsbV1-null strain has a developmental delay and exhibits differential growth attenuation in response to glucose levels. Collectively, our data support that the PSM regulates growth in response to metabolites and further defines biochemical features governing PSM-component interactions which could help in the development of novel PSM-targeted therapeutics.
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Affiliation(s)
- Shiomi Kuwabara
- Molecular Biology, Microbiology and Biochemistry Graduate Program, Southern Illinois University, Carbondale, IL 62901, United States
| | - Evan R Landers
- Molecular Biology, Microbiology and Biochemistry Graduate Program, Southern Illinois University, Carbondale, IL 62901, United States
| | - Derek J Fisher
- Molecular Biology, Microbiology and Biochemistry Graduate Program, Southern Illinois University, Carbondale, IL 62901, United States.,School of Biological Sciences, Southern Illinois University, Carbondale, IL 62901, United States
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Kumagai K, Sakai S, Ueno M, Kataoka M, Kobayashi S, Hanada K. Chlamydial Infection-Dependent Synthesis of Sphingomyelin as a Novel Anti-Chlamydial Target of Ceramide Mimetic Compounds. Int J Mol Sci 2022; 23:ijms232314697. [PMID: 36499025 PMCID: PMC9735676 DOI: 10.3390/ijms232314697] [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: 10/17/2022] [Revised: 11/09/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022] Open
Abstract
The obligate intracellular bacterium Chlamydia trachomatis is the major causative agent of bacterial sexually transmitted diseases worldwide. In infected cells, the ceramide transport protein (CERT) is recruited to inclusions, where C. trachomatis replicates using host-synthesized ceramide. The ceramide is converted to sphingomyelin (SM) by a chlamydial infection-dependent SM synthesis (cidSM-synthesis) pathway, which occurs even in the absence of the SM synthases (SMS)-1 and -2 of host cells. The ceramide mimetic compound (1R,3S)-HPA-12 and the nonmimetic compound E16A, both of which are potent inhibitors of CERT, repressed the proliferation of C. trachomatis in HeLa cells. Unexpectedly, (1R,3R)-HPA-12, a ceramide mimetic compound that lacks CERT inhibitory activity, also exhibited potent anti-chlamydial activity. Using endogenous SMS-knockout mutant HeLa cells, we revealed that (1R,3R)-HPA-12 mildly inhibited cidSM-synthesis. In addition, LC-MS analysis revealed that (1R,3R)-HPA-12 is converted to a phosphocholine-conjugated metabolite in an infection-dependent manner. Imaging analysis with a fluorescent analog of ceramide suggested that cidSM-synthesis occurs in the bacterial bodies and/or inclusions. Collectively, these results suggested that (1R,3R)-HPA-12 exerts its anti-chlamydia activity not only as an inhibitor of cidSM-synthesis, but also via putative toxic effects of its phosphocholine adduct, which is most likely produced by the cidSM-synthesis route.
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Affiliation(s)
- Keigo Kumagai
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
- Correspondence: (K.K.); (K.H.)
| | - Shota Sakai
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Masaharu Ueno
- Department of Natural Science, Graduate School of Advanced Technology and Science, Tokushima University, 2-1 Minami-jousanjima, Tokushima 770-8506, Japan
| | - Michiyo Kataoka
- Department of Pathology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Shu Kobayashi
- Department of Chemistry, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 110-0033, Japan
| | - Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
- Correspondence: (K.K.); (K.H.)
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Rosario C, Tan M. Chlamydia trachomatis RsbU Phosphatase Activity Is Inhibited by the Enolase Product, Phosphoenolpyruvate. J Bacteriol 2022; 204:e0017822. [PMID: 36121291 PMCID: PMC9578391 DOI: 10.1128/jb.00178-22] [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: 05/11/2022] [Accepted: 08/22/2022] [Indexed: 11/20/2022] Open
Abstract
The intracellular pathogen Chlamydia temporally regulates the expression of its genes, but the upstream signals that control transcription are not known. The best-studied regulatory pathway is a partner-switching mechanism that involves an anti-sigma factor, RsbW, which inhibits transcription by binding and sequestering the sigma subunit of RNA polymerase. RsbW is itself regulated by an anti-anti-sigma factor, RsbV, whose phosphorylation state is controlled by the phosphatase RsbU. In this study, we showed that Chlamydia trachomatis RsbU requires manganese or magnesium as a cofactor and dephosphorylates RsbV1 and RsbV2, which are the two chlamydial paralogs of RsbV. The gene for RsbU is adjacent to the enolase gene in a number of Chlamydia genomes, and we showed that eno and rsbU are cotranscribed from the same operon. In other bacteria, there is no known functional connection between the Rsb pathway and enolase, which is an enzyme in the glycolytic pathway. We found, however, that Chlamydia RsbU phosphatase activity was inhibited by phosphoenolpyruvate (PEP), the product of the enolase reaction, but not by 2-phosphoglycerate (2PGA), which is the substrate. These findings suggest that the enolase reaction and, more generally, glucose metabolism, may provide an upstream signal that regulates transcription in Chlamydia through the RsbW pathway. IMPORTANCE The RsbW pathway is a phosphorelay that regulates gene expression in Chlamydia, but its upstream signal has not been identified. We showed that RsbU, a phosphatase in this pathway, is inhibited by phosphoenolpyruvate, which is the product of the enolase reaction. As enolase is an enzyme in the glycolytic pathway, these results reveal an unrecognized link between glucose metabolism and gene regulation in chlamydiae. Moreover, as these intracellular bacteria acquire glucose from the infected host cell, our findings suggest that glucose availability may be an external signal that controls chlamydial gene expression.
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Affiliation(s)
- Christopher Rosario
- Department of Microbiology and Molecular Genetics, University of California, Irvine, California, USA
| | - Ming Tan
- Department of Microbiology and Molecular Genetics, University of California, Irvine, California, USA
- Department of Medicine, University of California, Irvine, California, USA
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36
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Chlamydia trachomatis inhibits apoptosis in infected cells by targeting the pro-apoptotic proteins Bax and Bak. Cell Death Differ 2022; 29:2046-2059. [PMID: 35397654 PMCID: PMC9525694 DOI: 10.1038/s41418-022-00995-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 11/08/2022] Open
Abstract
AbstractApoptosis acts in defense against microbial infection, and many infectious agents have developed strategies to inhibit host cell apoptosis. The human pathogen Chlamydia trachomatis (Ctr) is an obligate intracellular bacterium that strongly inhibits mitochondrial apoptosis of its human host cell but there is no agreement how the bacteria achieve this. We here provide a molecular analysis of chlamydial apoptosis-inhibition in infected human cells and demonstrate that the block of apoptosis occurs during the activation of the effectors of mitochondrial apoptosis, Bak and Bax. We use small-molecule Bcl-2-family inhibitors and gene targeting to show that previous models cannot explain the anti-apoptotic effect of chlamydial infection. Although the anti-apoptotic Bcl-2-family protein Mcl-1 was strongly upregulated upon infection, Mcl-1-deficient cells and cells where Mcl-1 was pharmacologically inactivated were still protected. Ctr-infection could inhibit both Bax- and Bak-induced apoptosis. Apoptotic Bax-oligomerization and association with the outer mitochondrial membrane was reduced upon chlamydial infection. Infection further inhibited apoptosis induced conformational changes of Bak, as evidenced by changes to protease sensitivity, oligomerization and release from the mitochondrial porin VDAC2. Mitochondria isolated from Ctr-infected cells were protected against the pro-apoptotic Bcl-2-family proteins Bim and tBid but this protection was lost upon protease digestion. However, the protective effect of Ctr-infection was reduced in cells lacking the Bax/Bak-regulator VDAC2. We further found that OmpA, a porin of the outer membrane of Ctr, associated upon experimental expression with mitochondria and inhibited apoptosis, phenocopying the effect of the infection. These results identify a novel way of apoptosis inhibition, involving only the most downstream modulator of mitochondrial apoptosis and suggest that Chlamydia has a protein dedicated to the inhibition of apoptosis to secure its survival in human cells.
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Vollmuth N, Schlicker L, Guo Y, Hovhannisyan P, Janaki-Raman S, Kurmasheva N, Schmitz W, Schulze A, Stelzner K, Rajeeve K, Rudel T. c-Myc plays a key role in IFN-γ-induced persistence of Chlamydia trachomatis. eLife 2022; 11:76721. [PMID: 36155135 PMCID: PMC9512400 DOI: 10.7554/elife.76721] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Chlamydia trachomatis (Ctr) can persist over extended times within their host cell and thereby establish chronic infections. One of the major inducers of chlamydial persistence is interferon-gamma (IFN-γ) released by immune cells as a mechanism of immune defence. IFN-γ activates the catabolic depletion of L-tryptophan (Trp) via indoleamine-2,3-dioxygenase (IDO), resulting in persistent Ctr. Here, we show that IFN-γ induces the downregulation of c-Myc, the key regulator of host cell metabolism, in a STAT1-dependent manner. Expression of c-Myc rescued Ctr from IFN-γ-induced persistence in cell lines and human fallopian tube organoids. Trp concentrations control c-Myc levels most likely via the PI3K-GSK3β axis. Unbiased metabolic analysis revealed that Ctr infection reprograms the host cell tricarboxylic acid (TCA) cycle to support pyrimidine biosynthesis. Addition of TCA cycle intermediates or pyrimidine/purine nucleosides to infected cells rescued Ctr from IFN-γ-induced persistence. Thus, our results challenge the longstanding hypothesis of Trp depletion through IDO as the major mechanism of IFN-γ-induced metabolic immune defence and significantly extends the understanding of the role of IFN-γ as a broad modulator of host cell metabolism.
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Affiliation(s)
- Nadine Vollmuth
- Department of Microbiology, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Lisa Schlicker
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Yongxia Guo
- Department of Microbiology, Biocenter, University of Wuerzburg, Wuerzburg, Germany.,College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Pargev Hovhannisyan
- Department of Microbiology, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | | | - Naziia Kurmasheva
- Department of Microbiology, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Werner Schmitz
- Department of Biochemistry and Molecular Biology, University of Wuerzburg, Würzburg, Germany
| | - Almut Schulze
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Department of Biochemistry and Molecular Biology, University of Wuerzburg, Würzburg, Germany
| | - Kathrin Stelzner
- Department of Microbiology, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Karthika Rajeeve
- Department of Microbiology, Biocenter, University of Wuerzburg, Wuerzburg, Germany.,Pathogen Biology, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, India
| | - Thomas Rudel
- Department of Microbiology, Biocenter, University of Wuerzburg, Wuerzburg, Germany
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Gao R, Zhang J, Geng H, Wang Y, Kang X, Geng S, Jiao X, Barrow P. The Loss of focA Gene Increases the Ability of Salmonella Enteritidis to Exit from Macrophages and Boosts Early Extraintestinal Spread for Systemic Infection in a Mouse Model. Microorganisms 2022; 10:microorganisms10081557. [PMID: 36013975 PMCID: PMC9414335 DOI: 10.3390/microorganisms10081557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/27/2022] [Accepted: 07/30/2022] [Indexed: 11/29/2022] Open
Abstract
Salmonella Enteritidis (SE) can spread from the intestines to cause systemic infection, mainly involving macrophages. Intramacrophage Salmonella exits and reinfects neighboring cells, leading to severe disease. Salmonella genes involved in exiting from macrophages are not well understood or fully identified. A focA::Tn5 mutant was identified by an in vitro assay, with increased ability to exit from macrophages. A defined SEΔfocA mutant and its complemented derivative strain, SEΔfocA::focA, were constructed to confirm this phenotype. Although the lethal ability of focA mutants was similar to that of the parental SE in mice, it was isolated earlier from the liver and spleen than the parental SE. focA mutants induced higher levels of proinflammatory IL-12 and TNF-α compared with the parental SE and SEΔfocA::focA. focA mutants showed higher cytotoxicity and lower formate concentrations than SE and SEΔfocA::focA, whereas there was no change in pyroptosis, apoptosis and flagella formation ability. These current data suggest that the focA gene plays an important role in regulating intramacrophage Salmonella exiting and extraintestinal spread in mice, although the specific mechanism requires further in-depth studies.
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Affiliation(s)
- Ran Gao
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Jian Zhang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Haoyu Geng
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Yaonan Wang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Xilong Kang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Shizhong Geng
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
- Correspondence: ; Tel.: +86-(514)-87971136; Fax: +86-(514)-87991747
| | - Xin’an Jiao
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; (R.G.); (J.Z.); (H.G.); (Y.W.); (X.K.); (X.J.)
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
- Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Paul Barrow
- School of Veterinary Medicine, University of Surrey, Daphne Jackson Road, Guildford GU2 7AL, UK;
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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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40
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Differential Effects of Small Molecule Inhibitors on the Intracellular Chlamydia Infection. mBio 2022; 13:e0107622. [PMID: 35703434 PMCID: PMC9426518 DOI: 10.1128/mbio.01076-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Chlamydia are obligate intracellular bacteria that reside within a membrane-bound compartment called the chlamydial inclusion inside a eukaryotic host cell. These pathogens have a complex biphasic developmental cycle, which involves conversion between a replicating, but noninfectious, reticulate body (RB) and an infectious elementary body (EB). Small molecule inhibitors have been reported to have deleterious effects on the intracellular Chlamydia infection, but these studies have typically been limited in terms of assays and time points of analysis. We compared published and novel inhibitors and showed that they can differentially alter inclusion size, chlamydial number and infectious EB production, and that these effects can vary over the course of the intracellular infection. Our results provide the justification for analysis with multiple assays performed either at the end of the infection or over a time course. We also show that this approach has the potential to identify the particular step in the developmental cycle that is impacted by the inhibitor. We furthermore propose that the magnitude of inhibitor-induced progeny defects are best quantified and compared by using a new value called maximal progeny production (Progenymax). As a demonstration of the validity of this systematic approach, we applied it to inhibitors of Akt and AMPK, which are host kinases involved in lipid synthesis and cholesterol trafficking pathways. Both inhibitors reduced EB production, but Akt disruption primarily decreased RB-to-EB conversion while AMPK inhibition paradoxically enhanced RB replication.
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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: 13] [Impact Index Per Article: 6.5] [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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42
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Scurtu LG, Jinga V, Simionescu O. Fascinating Molecular and Immune Escape Mechanisms in the Treatment of STIs (Syphilis, Gonorrhea, Chlamydia, and Herpes Simplex). Int J Mol Sci 2022; 23:ijms23073550. [PMID: 35408911 PMCID: PMC8998805 DOI: 10.3390/ijms23073550] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 03/21/2022] [Accepted: 03/23/2022] [Indexed: 02/04/2023] Open
Abstract
The incidence of syphilis, gonorrhea, chlamydia, and herpes simplex has increased over the last decade, despite the numerous prevention strategies. Worldwide scientists report a surge in drug-resistant infections, particularly in immunocompromised patients. Antigenic variations in syphilis enable long-term infection, but benzathine penicillin G maintains its efficiency, whereas macrolides should be recommended with caution. Mupirocin and zoliflodacin were recently introduced as therapies against ceftriaxone-resistant gonococcus, which poses a larger global threat. The gastrointestinal and prostatic potential reservoirs of Chlamydia trachomatis may represent the key towards complete eradication. Similar to syphilis, macrolides resistance has to be considered in genital chlamydiosis. Acyclovir-resistant HSV may respond to the novel helicase-primase inhibitors and topical imiquimod, particularly in HIV-positive patients. Novel drugs can overcome these challenges while nanocarriers enhance their potency, particularly in mucosal areas. This review summarizes the most recent and valuable discoveries regarding the immunopathogenic mechanisms of these sexually transmitted infections and discusses the challenges and opportunities of the novel molecules and nanomaterials.
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Affiliation(s)
- Lucian G. Scurtu
- Department of Dermatology I, Colentina Clinical Hospital, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 020125 Bucharest, Romania;
| | - Viorel Jinga
- Department of Urology, Clinical Hospital Prof. Dr. Th. Burghele, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 030167 Bucharest, Romania;
| | - Olga Simionescu
- Department of Dermatology I, Colentina Clinical Hospital, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 020125 Bucharest, Romania;
- Correspondence:
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Aranjuez GF, Kim J, Jewett TJ. The Chlamydia trachomatis Early Effector Tarp Outcompetes Fascin in Forming F-Actin Bundles In Vivo. Front Cell Infect Microbiol 2022; 12:811407. [PMID: 35300377 PMCID: PMC8921475 DOI: 10.3389/fcimb.2022.811407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/10/2022] [Indexed: 11/13/2022] Open
Abstract
The intracellular pathogen Chlamydia trachomatis secretes multiple early effectors into the host cell to promote invasion. A key early effector during host cell entry, Tarp (translocated actin-recruiting phosphoprotein) is comprised of multiple protein domains known to have roles in cell signaling, G-actin nucleation and F-actin bundle formation. In vitro, the actin bundles generated by Tarp are uncharacteristically flexible, however, in vivo, the biological significance of Tarp-mediated actin bundles remains unknown. We hypothesize that Tarp's ability to generate unique actin bundles, in part, facilitates chlamydial entry into epithelial cells. To study the in vivo interaction between Tarp and F-actin, we transgenically expressed Tarp in Drosophila melanogaster tissues. Tarp expressed in Drosophila is phosphorylated and forms F-actin-enriched aggregates in tissues. To gain insight into the significance of Tarp actin bundles in vivo, we utilized the well-characterized model system of mechanosensory bristle development in Drosophila melanogaster. Tarp expression in wild type flies produced curved bristles, indicating a perturbation in F-actin dynamics during bristle development. Two F-actin bundlers, Singed/Fascin and Forked/Espin, are important for normal bristle shape. Surprisingly, Tarp expression in the bristles displaced Singed/Fascin away from F-actin bundles. Tarp's competitive behavior against Fascin during F-actin bundling was confirmed in vitro. Loss of either singed or forked in flies leads to highly deformed bristles. Strikingly, Tarp partially rescued the loss of singed, reducing the severity of the bristle morphology defect. This work provides in vivo confirmation of Tarp's F-actin bundling activity and further uncovers a competitive behavior against the host bundler Singed/Fascin during bundle assembly. Also, we demonstrate the utility of Drosophila melanogaster as an in vivo cell biological platform to study bacterial effector function.
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Affiliation(s)
- George F. Aranjuez
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL, United States
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Petit TJ, Lebreton A. Adaptations of intracellular bacteria to vacuolar or cytosolic niches. Trends Microbiol 2022; 30:736-748. [DOI: 10.1016/j.tim.2022.01.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 12/28/2022]
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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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46
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Hornuß D, Müller MC, Rieg S. Chlamydien-Infektionen. ZEITSCHRIFT FUR GASTROENTEROLOGIE 2022. [DOI: 10.1055/a-1438-5557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Daniel Hornuß
- Gastroenterologie, Hepatologie, Endokrinologie und Infektiologie, Universitätsklinikum Freiburg, Klinik für Innere Medizin II, Freiburg, Deutschland
| | - Matthias C. Müller
- Gastroenterologie, Hepatologie, Endokrinologie und Infektiologie, Universitätsklinikum Freiburg, Klinik für Innere Medizin II, Freiburg, Deutschland
| | - Siegbert Rieg
- Gastroenterologie, Hepatologie, Endokrinologie und Infektiologie, Universitätsklinikum Freiburg, Klinik für Innere Medizin II, Freiburg, Deutschland
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47
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Liechti GW. Localized Peptidoglycan Biosynthesis in Chlamydia trachomatis Conforms to the Polarized Division and Cell Size Reduction Developmental Models. Front Microbiol 2021; 12:733850. [PMID: 34956109 PMCID: PMC8699169 DOI: 10.3389/fmicb.2021.733850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/17/2021] [Indexed: 11/13/2022] Open
Abstract
Cell size regulation in bacteria is a function of two basic cellular processes: the expansion of the cell envelope and its constriction at spatially defined points at what will eventually become the division plane. In most bacterial species, both cell wall expansion and restriction are dependent on peptidoglycan (PG), a structural polymer comprised of sugars and amino acids that imparts strength and rigidity to bacterial membranes. Pathogenic Chlamydia species are unique in that their cell walls contain very little PG, which is restricted almost entirely to the apparent division plane of the microbe's replicative forms. Very little is known about the degree to which PG affects the size and shape of C. trachomatis during its division process, and recent studies suggest the process is initiated via a polarized mechanism. We conducted an imaging study to ascertain the dimensions, orientation, and relative density of chlamydial PG throughout the organism's developmental cycle. Our analysis indicates that PG in replicating C. trachomatis can be associated with four, broad structural forms; polar/septal disks, small/thick rings, large rings, and small/thin rings. We found that PG density appeared to be highest in septal disks and small/thick rings, indicating that these structures likely have high PG synthesis to degradation ratios. We also discovered that as C. trachomatis progresses through its developmental cycle PG structures, on average, decrease in total volume, indicating that the average cell volume of chlamydial RBs likely decreases over time. When cells infected with C. trachomatis are treated with inhibitors of critical components of the microbe's two distinct PG synthases, we observed drastic differences in the ratio of PG synthesis to degradation, as well as the volume and shape of PG-containing structures. Overall, our results suggest that C. trachomatis PG synthases differentially regulate the expansion and contraction of the PG ring during both the expansion and constriction of the microbe's cell membrane during cell growth and division, respectively.
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Affiliation(s)
- George W Liechti
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, United States
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48
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Cross Talk between ARF1 and RhoA Coordinates the Formation of Cytoskeletal Scaffolds during Chlamydia Infection. mBio 2021; 12:e0239721. [PMID: 34903051 PMCID: PMC8669492 DOI: 10.1128/mbio.02397-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium that has developed sophisticated mechanisms to survive inside its infectious compartment, the inclusion. Notably, Chlamydia weaves an extensive network of microtubules (MTs) and actin filaments to enable interactions with host organelles and enhance its stability. Despite the global health and economic burden caused by this sexually transmitted pathogen, little is known about how actin and MT scaffolds are integrated into an increasingly complex virulence system. Previously, we established that the chlamydial effector InaC interacts with ARF1 to stabilize MTs. We now demonstrate that InaC regulates RhoA to control actin scaffolds. InaC relies on cross talk between ARF1 and RhoA to coordinate MTs and actin, where the presence of RhoA downregulates stable MT scaffolds and ARF1 activation inhibits actin scaffolds. Understanding how Chlamydia hijacks complex networks will help elucidate how this clinically significant pathogen parasitizes its host and reveal novel cellular signaling pathways.
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49
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Klasinc R, Reiter M, Digruber A, Tschulenk W, Walter I, Kirschner A, Spittler A, Stockinger H. A Novel Flow Cytometric Approach for the Quantification and Quality Control of Chlamydia trachomatis Preparations. Pathogens 2021; 10:1617. [PMID: 34959572 PMCID: PMC8706156 DOI: 10.3390/pathogens10121617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 11/27/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogenic bacterium with a biphasic developmental cycle manifesting two distinct morphological forms: infectious elementary bodies (EBs) and replicative intracellular reticulate bodies (RBs). Current standard protocols for quantification of the isolates assess infectious particles by titering inclusion-forming units, using permissive cell lines, and analyzing via immunofluorescence. Enumeration of total particle counts is achieved by counting labeled EBs/RBs using a fluorescence microscope. Both methods are time-consuming with a high risk of observer bias. For a better assessment of C. trachomatis preparations, we developed a simple and time-saving flow cytometry-based workflow for quantifying small particles, such as EBs with a size of 300 nm. This included optimization of gain and threshold settings with the addition of a neutral density filter for small-particle discrimination. The nucleic acid dye SYBR® Green I (SGI) was used together with propidium iodide and 5(6)-carboxyfluorescein diacetate to enumerate and discriminate between live and dead bacteria. We found no significant differences between the direct particle count of SGI-stained C. trachomatis preparations measured by microscopy or flow cytometry (p > 0.05). Furthermore, we completed our results by introducing a cell culture-independent viability assay. Our measurements showed very good reproducibility and comparability to the existing state-of-the-art methods, indicating that the evaluation of C. trachomatis preparations by flow cytometry is a fast and reliable method. Thus, our method facilitates an improved assessment of the quality of C. trachomatis preparations for downstream applications.
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Affiliation(s)
- Romana Klasinc
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria; (M.R.); (A.K.); (H.S.)
| | - Michael Reiter
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria; (M.R.); (A.K.); (H.S.)
| | - Astrid Digruber
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria;
| | - Waltraud Tschulenk
- Institute of Morphology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria; (W.T.); (I.W.)
| | - Ingrid Walter
- Institute of Morphology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria; (W.T.); (I.W.)
| | - Alexander Kirschner
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria; (M.R.); (A.K.); (H.S.)
- Division Water Quality & Health, Department Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, 3500 Krems, Austria
| | - Andreas Spittler
- Core Facility Flow Cytometry and Department of Surgery, Research Laboratories, Medical University of Vienna, 1090 Vienna, Austria;
| | - Hannes Stockinger
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria; (M.R.); (A.K.); (H.S.)
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50
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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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