1
|
Yount KS, Darville T. Immunity to Sexually Transmitted Bacterial Infections of the Female Genital Tract: Toward Effective Vaccines. Vaccines (Basel) 2024; 12:863. [PMID: 39203989 PMCID: PMC11359697 DOI: 10.3390/vaccines12080863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 07/19/2024] [Accepted: 07/27/2024] [Indexed: 09/03/2024] Open
Abstract
Sexually transmitted infections (STIs) caused by bacterial pathogens Chlamydia trachomatis, Neisseria gonorrhoeae, and Treponema pallidum present significant public health challenges. These infections profoundly impact reproductive health, leading to pelvic inflammatory disease, infertility, and increased susceptibility to other infections. Prevention measures, including antibiotic treatments, are limited by the often-asymptomatic nature of these infections, the need for repetitive and continual screening of sexually active persons, antibiotic resistance for gonorrhea, and shortages of penicillin for syphilis. While vaccines exist for viral STIs like human papillomavirus (HPV) and hepatitis B virus (HBV), there are no vaccines available for bacterial STIs. This review examines the immune responses in the female genital tract to these bacterial pathogens and the implications for developing effective vaccines against bacterial STIs.
Collapse
Affiliation(s)
| | - Toni Darville
- Department of Pediatrics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| |
Collapse
|
2
|
Jury B, Fleming C, Huston WM, Luu LDW. Molecular pathogenesis of Chlamydia trachomatis. Front Cell Infect Microbiol 2023; 13:1281823. [PMID: 37920447 PMCID: PMC10619736 DOI: 10.3389/fcimb.2023.1281823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/03/2023] [Indexed: 11/04/2023] Open
Abstract
Chlamydia trachomatis is a strict intracellular human pathogen. It is the main bacterial cause of sexually transmitted infections and the etiologic agent of trachoma, which is the leading cause of preventable blindness. Despite over 100 years since C. trachomatis was first identified, there is still no vaccine. However in recent years, the advancement of genetic manipulation approaches for C. trachomatis has increased our understanding of the molecular pathogenesis of C. trachomatis and progress towards a vaccine. In this mini-review, we aimed to outline the factors related to the developmental cycle phase and specific pathogenesis activity of C. trachomatis in order to focus priorities for future genetic approaches. We highlight the factors known to be critical for developmental cycle stages, gene expression regulatory factors, type III secretion system and their effectors, and individual virulence factors with known impacts.
Collapse
Affiliation(s)
- Brittany Jury
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | - Charlotte Fleming
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | | | - Laurence Don Wai Luu
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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.
Collapse
Affiliation(s)
| | | | - Stacey D. Gilk
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Godlee C, Holden DW. Transmembrane substrates of type three secretion system injectisomes. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001292. [PMID: 36748571 PMCID: PMC9993115 DOI: 10.1099/mic.0.001292] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The type three secretion system injectisome of Gram-negative bacterial pathogens injects virulence proteins, called effectors, into host cells. Effectors of mammalian pathogens carry out a range of functions enabling bacterial invasion, replication, immune suppression and transmission. The injectisome secretes two translocon proteins that insert into host cell membranes to form a translocon pore, through which effectors are delivered. A subset of effectors also integrate into infected cell membranes, enabling a unique range of biochemical functions. Both translocon proteins and transmembrane effectors avoid cytoplasmic aggregation and integration into the bacterial inner membrane. Translocated transmembrane effectors locate and integrate into the appropriate host membrane. In this review, we focus on transmembrane translocon proteins and effectors of bacterial pathogens of mammals. We discuss what is known about the mechanisms underlying their membrane integration, as well as the functions conferred by the position of injectisome effectors within membranes.
Collapse
Affiliation(s)
- Camilla Godlee
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK
- Present address: Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
- *Correspondence: Camilla Godlee, ;
| | - David W. Holden
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK
- *Correspondence: David W. Holden,
| |
Collapse
|
7
|
Chlamydia trachomatis Alters Mitochondrial Protein Composition and Secretes Effector Proteins That Target Mitochondria. mSphere 2022; 7:e0042322. [PMID: 36286535 PMCID: PMC9769516 DOI: 10.1128/msphere.00423-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Mitochondria are critical cellular organelles that perform a wide variety of functions, including energy production and immune regulation. To perform these functions, mitochondria contain approximately 1,500 proteins, the majority of which are encoded in the nuclear genome, translated in the cytoplasm, and translocated to the mitochondria using distinct mitochondrial targeting sequences (MTS). Bacterial proteins can also contain MTS and localize to the mitochondria. For the obligate intracellular human pathogen Chlamydia trachomatis, interaction with various host cell organelles promotes intracellular replication. However, the extent and mechanisms through which Chlamydia cells interact directly with mitochondria remain unclear. We investigated the presence of MTS in the C. trachomatis genome and discovered 30 genes encoding proteins with around 70% or greater probability of mitochondrial localization. Five are translocated to the mitochondria upon ectopic expression in HeLa cells. Mass spectrometry of isolated mitochondria from infected cells revealed that two of these proteins localize to the mitochondria during infection. Comparison of mitochondria from infected and uninfected cells suggests that chlamydial infection affects the mitochondrial protein composition. Around 125 host proteins were significantly decreased or absent in mitochondria from infected cells. Among these were proapoptotic factors and those related to mitochondrial fission/fusion dynamics. Conversely, 82 host proteins were increased in or specific to mitochondria of infected cells, many of which act as antiapoptotic factors and upregulators of cellular metabolism. These data support the notion that C. trachomatis specifically targets host mitochondria to manipulate cell fate decisions and metabolic function to support pathogen survival and replication. IMPORTANCE Obligate intracellular bacteria have evolved multiple means to promote their intracellular survival and replication within the otherwise harsh environment of the eukaryotic cell. Nutrient acquisition and avoidance of cellular defense mechanisms are critical to an intracellular lifestyle. Mitochondria are critical organelles that produce energy in the form of ATP and regulate programmed cell death responses to invasive pathogenic microbes. Cell death prior to completion of replication would be detrimental to the pathogen. C. trachomatis produces at least two and possibly more proteins that target the mitochondria. Collectively, C. trachomatis infection modulates the mitochondrial protein composition, favoring a profile suggestive of downregulation of apoptosis.
Collapse
|
8
|
The Chlamydia trachomatis inclusion membrane protein CT006 associates with lipid droplets in eukaryotic cells. PLoS One 2022; 17:e0264292. [PMID: 35192658 PMCID: PMC8863265 DOI: 10.1371/journal.pone.0264292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/07/2022] [Indexed: 11/19/2022] Open
Abstract
Chlamydia trachomatis causes genital and ocular infections in humans. This bacterial pathogen multiplies exclusively within host cells in a characteristic vacuole (inclusion) and delivers proteins such as inclusion membrane proteins (Incs) into the host cell. Here, we identified CT006 as a novel C. trachomatis protein that when expressed ectopically eukaryotic cells can associate with lipid droplets (LDs). A screen using Saccharomyces cerevisiae identified two Incs causing vacuolar protein sorting defects and seven Incs showing tropism for eukaryotic organelles. Ectopic expression in yeast and mammalian cells of genes encoding different fragments of CT006 revealed tropism for the endoplasmic reticulum and LDs. We identified a LD-targeting region within the first 88 amino acid residues of CT006, and positively charged residues important for this targeting. Comparing with the parental wild-type strain, cells infected by a newly generated C. trachomatis strain overproducing CT006 with a double hemagglutinin tag showed a slight increase in the area occupied by LDs within the inclusion region. However, we could not correlate this effect with the LD-targeting regions within CT006. We further showed that both the amino and carboxy-terminal regions of CT006, flanking the Inc-characteristic bilobed hydrophobic domain, are exposed to the host cell cytosol during C. trachomatis infection, supporting their availability to interact with host cell targets. Altogether, our data suggest that CT006 might participate in the interaction of LDs with C. trachomatis inclusions.
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Persistence Alters the Interaction between Chlamydia trachomatis and Its Host Cell. Infect Immun 2021; 89:e0068520. [PMID: 34001559 DOI: 10.1128/iai.00685-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In response to stress, the obligate intracellular pathogen Chlamydia trachomatis stops dividing and halts its biphasic developmental cycle. The infectious, extracellular form of this bacterium is highly susceptible to killing by the host immune response, and by pausing development, Chlamydia can survive in an intracellular, "aberrant" state for extended periods of time. The relevance of these aberrant forms has long been debated, and many questions remain concerning how they contribute to the persistence and pathogenesis of the organism. Using reporter cell lines, fluorescence microscopy, and a dipeptide labeling strategy, we measured the ability of C. trachomatis to synthesize, assemble, and degrade peptidoglycan under various aberrance-inducing conditions. We found that all aberrance-inducing conditions affect chlamydial peptidoglycan and that some actually halt the biosynthesis pathway early enough to prevent the release of an immunostimulatory peptidoglycan component, muramyl tripeptide. In addition, utilizing immunofluorescence and electron microscopy, we determined that the induction of aberrance can detrimentally affect the development of the microbe's pathogenic vacuole (the inclusion). Taken together, our data indicate that aberrant forms of Chlamydia generated by different environmental stressors can be sorted into two broad categories based on their ability to continue releasing peptidoglycan-derived, immunostimulatory muropeptides and their ability to secrete effector proteins that are normally expressed at the mid- and late stages of the microbe's developmental cycle. Our findings reveal a novel, immunoevasive feature inherent to a subset of aberrant chlamydial forms and provide clarity and context to the numerous persistence mechanisms employed by these ancient, genetically reduced microbes.
Collapse
|
11
|
Huang X, Tan J, Chen X, Liu M, Zhu H, Li W, He Z, Han J, Ma C. Akt Phosphorylation Influences Persistent Chlamydial Infection and Chlamydia-Induced Golgi Fragmentation Without Involving Rab14. Front Cell Infect Microbiol 2021; 11:675890. [PMID: 34169005 PMCID: PMC8218875 DOI: 10.3389/fcimb.2021.675890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 04/29/2021] [Indexed: 11/30/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium that causes multiple diseases involving the eyes, gastrointestinal tract, and genitourinary system. Previous studies have identified that in acute chlamydial infection, C. trachomatis requires Akt pathway phosphorylation and Rab14-positive vesicles to transmit essential lipids from the Golgi apparatus in survival and replication. However, the roles that Akt phosphorylation and Rab14 play in persistent chlamydial infection remain unclear. Here, we discovered that the level of Akt phosphorylation was lower in persistent chlamydial infection, and positively correlated with the effect of activating the development of Chlamydia but did not change the infectivity and 16s rRNA gene expression. Rab14 was found to exert a limited effect on persistent infection. Akt phosphorylation might regulate Chlamydia development and Chlamydia-induced Golgi fragmentation in persistent infection without involving Rab14. Our results provide a new insight regarding the potential of synergistic repressive effects of an Akt inhibitor with antibiotics in the treatment of persistent chlamydial infection induced by penicillin.
Collapse
Affiliation(s)
- Xiaobao Huang
- Department of Dermatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jinfeng Tan
- Department of Gynecology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xiaohong Chen
- Department of Dermatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Mingna Liu
- Department of Dermatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Huiling Zhu
- Department of Dermatology, The First Affiliated Hospital of Guangzhou Medical College, Guangzhou, China
| | - Wenjing Li
- Department of Dermatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhenjian He
- School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Jiande Han
- Department of Dermatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Chunguang Ma
- Department of Dermatology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|
12
|
Del Balzo D, Capmany A, Cebrian I, Damiani MT. Chlamydia trachomatis Infection Impairs MHC-I Intracellular Trafficking and Antigen Cross-Presentation by Dendritic Cells. Front Immunol 2021; 12:662096. [PMID: 33936099 PMCID: PMC8082151 DOI: 10.3389/fimmu.2021.662096] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/26/2021] [Indexed: 11/21/2022] Open
Abstract
During cross-presentation, exogenous antigens (i.e. intracellular pathogens or tumor cells) are internalized and processed within the endocytic system and also by the proteasome in the cytosol. Then, antigenic peptides are associated with Major Histocompatibility Complex (MHC) class I molecules and these complexes transit to the plasma membrane in order to trigger cytotoxic immune responses through the activation of CD8+ T lymphocytes. Dendritic cells (DCs) are particularly adapted to achieve efficient antigen cross-presentation and their endocytic network displays important roles during this process, including a sophisticated MHC-I transport dependent on recycling compartments. In this study, we show that C. trachomatis, an obligate intracellular pathogen that exhibits multiple strategies to evade the immune system, is able to induce productive infections in the murine DC line JAWS-II. Our results show that when C. trachomatis infects these cells, the bacteria-containing vacuole strongly recruits host cell recycling vesicles, but no other endosomal compartments. Furthermore, we found that chlamydial infection causes significant alterations of MHC-I trafficking in JAWS-II DCs: reduced levels of MHC-I expression at the cell surface, disruption of the perinuclear MHC-I intracellular pool, and impairment of MHC-I endocytic recycling to the plasma membrane. We observed that all these modifications lead to a hampered cross-presentation ability of soluble and particulate antigens by JAWS-II DCs and primary bone marrow-derived DCs. In summary, our findings provide substantial evidence that C. trachomatis hijacks the DC endocytic recycling system, causing detrimental changes on MHC-I intracellular transport, which are relevant for competent antigen cross-presentation.
Collapse
Affiliation(s)
- Diego Del Balzo
- Biochemistry and Immunity Laboratory, School of Medicine, University of Cuyo, IMBECU-CONICET, Centro Universitario, Mendoza, Argentina
| | - Anahí Capmany
- Biochemistry and Immunity Laboratory, School of Medicine, University of Cuyo, IMBECU-CONICET, Centro Universitario, Mendoza, Argentina
| | - Ignacio Cebrian
- Instituto de Histología y Embriología de Mendoza (IHEM)-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - María Teresa Damiani
- Biochemistry and Immunity Laboratory, School of Medicine, University of Cuyo, IMBECU-CONICET, Centro Universitario, Mendoza, Argentina
| |
Collapse
|
13
|
Yong X, Mao L, Shen X, Zhang Z, Billadeau DD, Jia D. Targeting Endosomal Recycling Pathways by Bacterial and Viral Pathogens. Front Cell Dev Biol 2021; 9:648024. [PMID: 33748141 PMCID: PMC7970000 DOI: 10.3389/fcell.2021.648024] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 02/15/2021] [Indexed: 12/19/2022] Open
Abstract
Endosomes are essential cellular stations where endocytic and secretory trafficking routes converge. Proteins transiting at endosomes can be degraded via lysosome, or recycled to the plasma membrane, trans-Golgi network (TGN), or other cellular destinations. Pathways regulating endosomal recycling are tightly regulated in order to preserve organelle identity, to maintain lipid homeostasis, and to support other essential cellular functions. Recent studies have revealed that both pathogenic bacteria and viruses subvert host endosomal recycling pathways for their survival and replication. Several host factors that are frequently targeted by pathogens are being identified, including retromer, TBC1D5, SNX-BARs, and the WASH complex. In this review, we will focus on the recent advances in understanding how intracellular bacteria, human papillomavirus (HPV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hijack host endosomal recycling pathways. This exciting work not only reveals distinct mechanisms employed by pathogens to manipulate host signaling pathways, but also deepens our understanding of the molecular intricacies regulating endosomal receptor trafficking.
Collapse
Affiliation(s)
- Xin Yong
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Lejiao Mao
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Xiaofei Shen
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Zhen Zhang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| | - Daniel D. Billadeau
- Division of Oncology Research and Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN, United States
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China
| |
Collapse
|
14
|
Andersen SE, Bulman LM, Steiert B, Faris R, Weber MM. Got mutants? How advances in chlamydial genetics have furthered the study of effector proteins. Pathog Dis 2021; 79:ftaa078. [PMID: 33512479 PMCID: PMC7862739 DOI: 10.1093/femspd/ftaa078] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/17/2020] [Indexed: 02/07/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of infectious blindness and a sexually transmitted infection. All chlamydiae are obligate intracellular bacteria that replicate within a membrane-bound vacuole termed the inclusion. From the confines of the inclusion, the bacteria must interact with many host organelles to acquire key nutrients necessary for replication, all while promoting host cell viability and subverting host defense mechanisms. To achieve these feats, C. trachomatis delivers an arsenal of virulence factors into the eukaryotic cell via a type 3 secretion system (T3SS) that facilitates invasion, manipulation of host vesicular trafficking, subversion of host defense mechanisms and promotes bacteria egress at the conclusion of the developmental cycle. A subset of these proteins intercalate into the inclusion and are thus referred to as inclusion membrane proteins. Whereas others, referred to as conventional T3SS effectors, are released into the host cell where they localize to various eukaryotic organelles or remain in the cytosol. Here, we discuss the functions of T3SS effector proteins with a focus on how advances in chlamydial genetics have facilitated the identification and molecular characterization of these important factors.
Collapse
Affiliation(s)
- Shelby E Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Lanci M Bulman
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Brianna Steiert
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Mary M Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| |
Collapse
|
15
|
Host and Bacterial Glycolysis during Chlamydia trachomatis Infection. Infect Immun 2020; 88:IAI.00545-20. [PMID: 32900818 DOI: 10.1128/iai.00545-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 09/02/2020] [Indexed: 12/14/2022] Open
Abstract
The obligate intracellular pathogen Chlamydia trachomatis is the leading cause of noncongenital blindness and causative agent of the most common sexually transmitted infection of bacterial origin. With a reduced genome, C. trachomatis is dependent on its host for survival, in part due to a need for the host cell to compensate for incomplete bacterial metabolic pathways. However, relatively little is known regarding how C. trachomatis is able to hijack host cell metabolism. In this study, we show that two host glycolytic enzymes, aldolase A and pyruvate kinase, as well as lactate dehydrogenase, are enriched at the C. trachomatis inclusion membrane during infection. Inclusion localization was not species specific, since a similar phenotype was observed with C. muridarum Time course experiments showed that the number of positive inclusions increased throughout the developmental cycle. In addition, these host enzymes colocalized to the same inclusion, and their localization did not appear to be dependent on sustained bacterial protein synthesis or on intact host actin, vesicular trafficking, or microtubules. Depletion of the host glycolytic enzyme aldolase A resulted in decreased inclusion size and infectious progeny production, indicating a role for host glycolysis in bacterial growth. Finally, quantitative PCR analysis showed that expression of C. trachomatis glycolytic enzymes inversely correlated with host enzyme localization at the inclusion. We discuss potential mechanisms leading to inclusion localization of host glycolytic enzymes and how it could benefit the bacteria. Altogether, our findings provide further insight into the intricate relationship between host and bacterial metabolism during Chlamydia infection.
Collapse
|
16
|
Faris R, Merling M, Andersen SE, Dooley CA, Hackstadt T, Weber MM. Chlamydia trachomatis CT229 Subverts Rab GTPase-Dependent CCV Trafficking Pathways to Promote Chlamydial Infection. Cell Rep 2020; 26:3380-3390.e5. [PMID: 30893609 DOI: 10.1016/j.celrep.2019.02.079] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/28/2018] [Accepted: 02/20/2019] [Indexed: 01/25/2023] Open
Abstract
Chlamydial infection requires the formation of a membrane-bound vacuole, termed the inclusion, that undergoes extensive interactions with select host organelles. The importance of the Inc protein CT229 in the formation and maintenance of the chlamydial inclusion was recently highlighted by studies demonstrating that its absence during infection results in reduced bacterial replication, premature inclusion lysis, and host cell death. Previous reports have indicated that CT229 binds Rab GTPases; however, the physiological implications of this interaction are unknown. Here, we show that CT229 regulates host multivesicular trafficking by recruiting multiple Rab GTPases and their cognate effectors to the inclusion. We demonstrate that CT229 specifically modulates clathrin-coated vesicle trafficking and regulates the trafficking of transferrin and the mannose-6-phosphate receptor, both of which are crucial for proper chlamydial development. This study highlights CT229 as a master regulator of multiple host vesicular trafficking pathways essential for chlamydial infection.
Collapse
Affiliation(s)
- Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Marlena Merling
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Biology, University of Dayton, Dayton, OH 45469, USA
| | - Shelby E Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Cheryl A Dooley
- Host Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Disease, NIH, Hamilton, MT 59840, USA
| | - Ted Hackstadt
- Host Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Disease, NIH, Hamilton, MT 59840, USA
| | - Mary M Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
| |
Collapse
|
17
|
Gitsels A, Sanders N, Vanrompay D. Chlamydial Infection From Outside to Inside. Front Microbiol 2019; 10:2329. [PMID: 31649655 PMCID: PMC6795091 DOI: 10.3389/fmicb.2019.02329] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 09/24/2019] [Indexed: 12/16/2022] Open
Abstract
Chlamydia are obligate intracellular bacteria, characterized by a unique biphasic developmental cycle. Specific interactions with the host cell are crucial for the bacteria’s survival and amplification because of the reduced chlamydial genome. At the start of infection, pathogen-host interactions are set in place in order for Chlamydia to enter the host cell and reach the nutrient-rich peri-Golgi region. Once intracellular localization is established, interactions with organelles and pathways of the host cell enable the necessary hijacking of host-derived nutrients. Detailed information on the aforementioned processes will increase our understanding on the intracellular pathogenesis of chlamydiae and hence might lead to new strategies to battle chlamydial infection. This review summarizes how chlamydiae generate their intracellular niche in the host cell, acquire host-derived nutrients in order to enable their growth and finally exit the host cell in order to infect new cells. Moreover, the evolution in the development of molecular genetic tools, necessary for studying the chlamydial infection biology in more depth, is discussed in great detail.
Collapse
Affiliation(s)
- Arlieke Gitsels
- Laboratory for Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Niek Sanders
- Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Daisy Vanrompay
- Laboratory for Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| |
Collapse
|
18
|
Banhart S, Schäfer EK, Gensch JM, Heuer D. Sphingolipid Metabolism and Transport in Chlamydia trachomatis and Chlamydia psittaci Infections. Front Cell Dev Biol 2019; 7:223. [PMID: 31637241 PMCID: PMC6787139 DOI: 10.3389/fcell.2019.00223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/20/2019] [Indexed: 12/05/2022] Open
Abstract
Chlamydia species infect a large range of vertebral hosts and have become of major economic and public health concern over the last decades. They are obligate intracellular bacteria that undergo a unique cycle of development characterized by the presence of two distinct bacterial forms. After infection of the host cell, Chlamydia are found inside a membrane-bound compartment, the inclusion. The surrounding membrane of the inclusion contributes to the host-Chlamydia interface and specific pathogen-derived Inc proteins shape this interface allowing interactions with distinct cellular proteins. In contrast to many other bacteria, Chlamydia species acquire sphingomyelin from the host cell. In recent years a clearer picture of how Chlamydia trachomatis acquires this lipid emerged showing that the bacteria interact with vesicular and non-vesicular transport pathways that involve the recruitment of specific RAB proteins and the lipid-transfer protein CERT. These interactions contribute to the development of a new sphingomyelin-producing compartment inside the host cell. Interestingly, recruitment of CERT is conserved among different Chlamydia species including Chlamydia psittaci. Here we discuss our current understanding on the molecular mechanisms used by C. trachomatis and C. psittaci to establish these interactions and to create a novel sphingomyelin-producing compartment inside the host cell important for the infection.
Collapse
Affiliation(s)
- Sebastian Banhart
- Unit 'Sexually Transmitted Bacterial Infections', Department for Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Elena K Schäfer
- Unit 'Sexually Transmitted Bacterial Infections', Department for Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Jean-Marc Gensch
- Unit 'Sexually Transmitted Bacterial Infections', Department for Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Dagmar Heuer
- Unit 'Sexually Transmitted Bacterial Infections', Department for Infectious Diseases, Robert Koch Institute, Berlin, Germany
| |
Collapse
|
19
|
Bugalhão JN, Mota LJ. The multiple functions of the numerous Chlamydia trachomatis secreted proteins: the tip of the iceberg. MICROBIAL CELL 2019; 6:414-449. [PMID: 31528632 PMCID: PMC6717882 DOI: 10.15698/mic2019.09.691] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chlamydia trachomatis serovars are obligate intracellular bacterial pathogens mainly causing ocular and urogenital infections that affect millions of people worldwide and which can lead to blindness or sterility. They reside and multiply intracellularly within a membrane-bound vacuolar compartment, known as inclusion, and are characterized by a developmental cycle involving two morphologically and physiologically distinct chlamydial forms. Completion of the developmental cycle involves the secretion of > 70 C. trachomatis proteins that function in the host cell cytoplasm and nucleus, in the inclusion membrane and lumen, and in the extracellular milieu. These proteins can, for example, interfere with the host cell cytoskeleton, vesicular and non-vesicular transport, metabolism, and immune signalling. Generally, this promotes C. trachomatis invasion into, and escape from, host cells, the acquisition of nutrients by the chlamydiae, and evasion of cell-autonomous, humoral and cellular innate immunity. Here, we present an in-depth review on the current knowledge and outstanding questions about these C. trachomatis secreted proteins.
Collapse
Affiliation(s)
- Joana N Bugalhão
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Luís Jaime Mota
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| |
Collapse
|
20
|
Rab39a and Rab39b Display Different Intracellular Distribution and Function in Sphingolipids and Phospholipids Transport. Int J Mol Sci 2019; 20:ijms20071688. [PMID: 30987349 PMCID: PMC6480249 DOI: 10.3390/ijms20071688] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/14/2019] [Accepted: 03/27/2019] [Indexed: 12/23/2022] Open
Abstract
Rab GTPases define the identity and destiny of vesicles. Some of these small GTPases present isoforms that are expressed differentially along developmental stages or in a tissue-specific manner, hence comparative analysis is difficult to achieve. Here, we describe the intracellular distribution and function in lipid transport of the poorly characterized Rab39 isoforms using typical cell biology experimental tools and new ones developed in our laboratory. We show that, despite their amino acid sequence similarity, Rab39a and Rab39b display non-overlapping intracellular distribution. Rab39a localizes in the late endocytic pathway, mainly at multivesicular bodies. In contrast, Rab39b distributes in the secretory network, at the endoplasmic reticulum/cis-Golgi interface. Therefore, Rab39a controls trafficking of lipids (sphingomyelin and phospholipids) segregated at multivesicular bodies, whereas Rab39b transports sphingolipids biosynthesized at the endoplasmic reticulum-Golgi factory. Interestingly, lyso bis-phosphatidic acid is exclusively transported by Rab39a, indicating that both isoforms do not exert identical functions in lipid transport. Conveniently, the requirement of eukaryotic lipids by the intracellular pathogen Chlamydia trachomatis rendered useful for dissecting and distinguishing Rab39a- and Rab39b-controlled trafficking pathways. Our findings provide comparative insights about the different subcellular distribution and function in lipid transport of the two Rab39 isoforms.
Collapse
|
21
|
Capmany A, Gambarte Tudela J, Alonso Bivou M, Damiani MT. Akt/AS160 Signaling Pathway Inhibition Impairs Infection by Decreasing Rab14-Controlled Sphingolipids Delivery to Chlamydial Inclusions. Front Microbiol 2019; 10:666. [PMID: 31001235 PMCID: PMC6456686 DOI: 10.3389/fmicb.2019.00666] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/18/2019] [Indexed: 12/26/2022] Open
Abstract
Chlamydia trachomatis, an obligate intracellular bacterium, intercepts different trafficking pathways of the host cell to acquire essential lipids for its survival and replication, particularly from the Golgi apparatus via a Rab14-mediated transport. Molecular mechanisms underlying how these bacteria manipulate intracellular transport are a matter of intense study. Here, we show that C. trachomatis utilizes Akt/AS160 signaling pathway to promote sphingolipids delivery to the chlamydial inclusion through Rab14-controlled vesicular transport. C. trachomatis provokes Akt phosphorylation along its entire developmental life cycle and recruits phosphorylated Akt (pAkt) to the inclusion membrane. As a consequence, Akt Substrate of 160 kDa (AS160), also known as TBC1D4, a GTPase Activating Protein (GAP) for Rab14, is phosphorylated and therefore inactivated. Phosphorylated AS160 (pAS160) loses its ability to promote GTP hydrolysis, favoring Rab14 binding to GTP. Akt inhibition by an allosteric isoform-specific Akt inhibitor (iAkt) prevents AS160 phosphorylation and reduces Rab14 recruitment to chlamydial inclusions. iAkt further impairs sphingolipids acquisition by C. trachomatis-inclusion and provokes lipid retention at the Golgi apparatus. Consequently, treatment with iAkt decreases chlamydial inclusion size, bacterial multiplication, and infectivity in a dose-dependent manner. Similar results were found in AS160-depleted cells. By electron microscopy, we observed that iAkt generates abnormal bacterial forms as those reported after sphingolipids deprivation or Rab14 silencing. Taken together, our findings indicate that targeting the Akt/AS160/Rab14 axis could constitute a novel strategy to limit chlamydial infections, mainly for those caused by antibiotic-resistant bacteria.
Collapse
Affiliation(s)
- Anahí Capmany
- Laboratorio de Bioquímica e Inmunidad, Área de Química Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas, Mendoza, Argentina
| | - Julián Gambarte Tudela
- Laboratorio de Bioquímica e Inmunidad, Área de Química Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Instituto de Medicina y Biología Experimental de Cuyo, Consejo Nacional de Investigaciones Científicas y Técnicas, Mendoza, Argentina
| | - Mariano Alonso Bivou
- Laboratorio de Bioquímica e Inmunidad, Área de Química Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Instituto de Medicina y Biología Experimental de Cuyo, Consejo Nacional de Investigaciones Científicas y Técnicas, Mendoza, Argentina
| | - María T Damiani
- Laboratorio de Bioquímica e Inmunidad, Área de Química Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Instituto de Medicina y Biología Experimental de Cuyo, Consejo Nacional de Investigaciones Científicas y Técnicas, Mendoza, Argentina
| |
Collapse
|
22
|
Darville T, Albritton HL, Zhong W, Dong L, O'Connell CM, Poston TB, Quayle AJ, Goonetilleke N, Wiesenfeld HC, Hillier SL, Zheng X. Anti-chlamydia IgG and IgA are insufficient to prevent endometrial chlamydia infection in women, and increased anti-chlamydia IgG is associated with enhanced risk for incident infection. Am J Reprod Immunol 2019; 81:e13103. [PMID: 30784128 DOI: 10.1111/aji.13103] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 12/23/2022] Open
Abstract
PROBLEM Chlamydia infections in women can ascend to the upper genital tract, and repeated infections are common, placing women at risk for sequelae. The protective role of anti-chlamydia antibodies to surface exposed antigens in ascending and incident infection is unclear. METHOD OF STUDY A whole-bacterial ELISA was used to quantify chlamydia-specific IgG and IgA in serum and cervical secretions of 151 high-risk women followed longitudinally. Correlations were determined between antibody and cervical burden, and causal mediation analysis investigated the effect of antibody on ascension. We examined the relationship of antibody to incident infection using the marginal Cox model. RESULTS Serum and cervical anti-chlamydia IgG and cervical IgA levels correlated inversely with cervical burden. While lower burden was associated with reduced ascension, causal mediation analysis revealed that the indirect effects of antibody mediated through reductions in bacterial burden were insufficient to prevent ascension. Analysis of women uninfected at enrollment revealed that serum and cervical anti-chlamydia IgG were associated with increased risk of incident infection; hazard ratio increased 3.6-fold (95% CI, 1.3-10.3), and 22.6-fold (95% CI, 3.1-165.2) with each unit of serum and cervical IgG, respectively. CONCLUSION Although anti-chlamydia IgG and IgA correlated with reduced cervical chlamydia burden, they failed to prevent ascension and increased levels of anti-chlamydia IgG were associated with increased risk for incident infection.
Collapse
Affiliation(s)
- Toni Darville
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina
| | - Hannah L Albritton
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Wujuan Zhong
- Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina
| | - Li Dong
- Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina
| | | | - Taylor B Poston
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina
| | - Alison J Quayle
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Nilu Goonetilleke
- Departments of Microbiology & Immunology and Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Harold C Wiesenfeld
- Department of Obstetrics, Gynecology and Reproductive Sciences, The University of Pittsburgh School of Medicine, The Magee-Womens Research Institute, Pittsburgh, Pennsylvania
| | - Sharon L Hillier
- Department of Obstetrics, Gynecology and Reproductive Sciences, The University of Pittsburgh School of Medicine, The Magee-Womens Research Institute, Pittsburgh, Pennsylvania
| | - Xiaojing Zheng
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina
| |
Collapse
|
23
|
Abstract
Chlamydia trachomatis resides and replicates within a membranous vacuole, termed the inclusion. A group of Type III secreted effector proteins, the inclusion membrane proteins (Inc), are embedded within the inclusion membrane and facilitate the interaction of the inclusion with host cell organelles. These interactions are vital for bacterial replication and allow for the acquisition of essential nutrients from the host cell. However, it is not known if Inc proteins function independently or require interactions with other Inc proteins to function. This chapter describes a system to test the homotypic/heterotypic interactions of Inc proteins through the coinfection of Chlamydia strains expressing differently tagged inclusion membrane proteins. Our approach takes advantage of the natural homotypic fusion of inclusions and allows for the study of Inc protein interactions when they are embedded within the inclusion membrane.
Collapse
Affiliation(s)
- Rachel Ende
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA.
| |
Collapse
|
24
|
Martinez E, Siadous FA, Bonazzi M. Tiny architects: biogenesis of intracellular replicative niches by bacterial pathogens. FEMS Microbiol Rev 2018; 42:425-447. [PMID: 29596635 DOI: 10.1093/femsre/fuy013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/26/2018] [Indexed: 11/13/2022] Open
Abstract
Co-evolution of bacterial pathogens with their hosts led to the emergence of a stunning variety of strategies aiming at the evasion of host defences, colonisation of host cells and tissues and, ultimately, the establishment of a successful infection. Pathogenic bacteria are typically classified as extracellular and intracellular; however, intracellular lifestyle comes in many different flavours: some microbes rapidly escape to the cytosol whereas other microbes remain within vacuolar compartments and harness membrane trafficking pathways to generate their host-derived, pathogen-specific replicative niche. Here we review the current knowledge on a variety of vacuolar lifestyles, the effector proteins used by bacteria as tools to take control of the host cell and the main membrane trafficking signalling pathways targeted by vacuolar pathogens as source of membranes and nutrients. Finally, we will also discuss how host cells have developed countermeasures to sense the biogenesis of the aberrant organelles harbouring bacteria. Understanding the dialogue between bacterial and eukaryotic proteins is the key to unravel the molecular mechanisms of infection and in turn, this may lead to the identification of new targets for the development of new antimicrobials.
Collapse
Affiliation(s)
- Eric Martinez
- IRIM, University of Montpellier, CNRS, 34293 Montpellier, France
| | | | - Matteo Bonazzi
- IRIM, University of Montpellier, CNRS, 34293 Montpellier, France
| |
Collapse
|
25
|
Shaw JH, Key CE, Snider TA, Sah P, Shaw EI, Fisher DJ, Lutter EI. Genetic Inactivation of Chlamydia trachomatis Inclusion Membrane Protein CT228 Alters MYPT1 Recruitment, Extrusion Production, and Longevity of Infection. Front Cell Infect Microbiol 2018; 8:415. [PMID: 30555802 PMCID: PMC6284022 DOI: 10.3389/fcimb.2018.00415] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/08/2018] [Indexed: 02/01/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen with global health and economic impact. Upon infection, C. trachomatis resides within a protective niche, the inclusion, wherein it replicates and usurps host cell machinery and resources. The inclusion membrane is the key host-pathogen interface that governs specific protein-protein interactions to manipulate host signaling pathways. At the conclusion of the infection cycle, C. trachomatis exits the host cell via lysis or extrusion. Extrusion depends on the phosphorylation state of myosin light chain 2 (MLC2); the extent of phosphorylation is determined by the ongoing opposing activities of myosin phosphatase (MYPT1) and myosin kinase (MLCK). Previously, it was shown that MYPT1 is recruited to the inclusion and interacts with CT228 for regulation of host cell egress. In this study, we generated a targeted chromosomal mutation of CT228 (L2-ΔCT228) using the TargeTron system and demonstrate a loss of MYPT1 recruitment and increase in extrusion production in vitro. Mutation of CT228 did not affect chlamydial growth in cell culture or recruitment of MLC2. Moreover, we document a delay in clearance of L2-ΔCT228 during murine intravaginal infection as well as a reduction in systemic humoral response, relative to L2-wild type. Taken together, the data suggest that loss of MYPT1 recruitment (as a result of CT228 disruption) regulates the degree of host cell exit via extrusion and affects the longevity of infection in vivo.
Collapse
Affiliation(s)
- Jennifer H. Shaw
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, United States,*Correspondence: Jennifer H. Shaw
| | - Charlotte E. Key
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, United States
| | - Timothy A. Snider
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, United States
| | - Prakash Sah
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States
| | - Edward I. Shaw
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States
| | - Derek J. Fisher
- Department of Microbiology, Southern Illinois University, Carbondale, IL, United States
| | - Erika I. Lutter
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States,Erika I. Lutter
| |
Collapse
|
26
|
Fischer A, Rudel T. Safe haven under constant attack-The Chlamydia-containing vacuole. Cell Microbiol 2018; 20:e12940. [PMID: 30101516 DOI: 10.1111/cmi.12940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 07/24/2018] [Accepted: 07/31/2018] [Indexed: 11/30/2022]
Abstract
Chlamydia belong to the group of obligate intracellular bacteria that reside in a membrane bound vacuole during the entire intracellular phase of their life cycle. This vacuole called inclusion shields the bacteria from adverse influences in the cytosol of the host cell like the destructive machinery of the cell-autonomous defence system. The inclusion thereby prevents the digestion and eradication in specialised compartments of the intact and viable cell called phagolysosomes or autophagolysosomes. It is becoming more and more evident that keeping the inclusion intact also prevents the onset of cell intrinsic cell death programmes that are activated upon damage of the inclusion and direct the cell to destruct itself and the pathogen inside. Chlamydia secrete numerous proteins into the inclusion membrane to protect and stabilise their unique niche inside the host cell. We will focus in this review on the diverse attack strategies of the host aiming at the destruction of the Chlamydia-containing inclusion and will summarise the current knowledge on the protection mechanisms elaborated by the bacteria to maintain the integrity of their replication niche.
Collapse
Affiliation(s)
- Annette Fischer
- Department of Microbiology, University of Würzburg Biocenter, Würzburg, Germany
| | - Thomas Rudel
- Department of Microbiology, University of Würzburg Biocenter, Würzburg, Germany
| |
Collapse
|
27
|
Almeida F, Luís MP, Pereira IS, Pais SV, Mota LJ. The Human Centrosomal Protein CCDC146 Binds Chlamydia trachomatis Inclusion Membrane Protein CT288 and Is Recruited to the Periphery of the Chlamydia-Containing Vacuole. Front Cell Infect Microbiol 2018; 8:254. [PMID: 30094225 PMCID: PMC6070772 DOI: 10.3389/fcimb.2018.00254] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/04/2018] [Indexed: 01/12/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular human pathogen causing mainly ocular and genital infections of significant clinical and public health impact. C. trachomatis multiplies intracellularly in a membrane bound vacuole, known as inclusion. Both extracellularly and from within the inclusion, C. trachomatis uses a type III secretion system to deliver several effector proteins into the cytoplasm of host cells. A large proportion of these effectors, the inclusion membrane (Inc) proteins, are exposed to the host cell cytosol but possess a characteristic hydrophobic domain mediating their insertion in the inclusion membrane. By yeast two-hybrid, we found that C. trachomatis Inc CT288 interacts with the human centrosomal protein CCDC146 (coiled-coil domain-containing protein 146). The interaction was also detected by co-immunoprecipitation in mammalian cells either ectopically expressing CCDC146 and CT288 or ectopically expressing CCDC146 and infected by a C. trachomatis strain expressing epitope-tagged and inclusion membrane-localized CT288. In uninfected mammalian cells, ectopically expressed full-length CCDC146 (955 amino acid residues) localized at the centrosome; but in cells infected by wild-type C. trachomatis, its centrosomal localization was less evident and CCDC146 accumulated around the inclusion. Recruitment of CCDC146 to the inclusion periphery did not require intact host Golgi, microtubules or microfilaments, but was dependent on chlamydial protein synthesis. Full-length CCDC146 also accumulated at the periphery of the inclusion in cells infected by a C. trachomatis ct288 mutant; however, a C-terminal fragment of CCDC146 (residues 692–955), which interacts with CT288, showed differences in localization at the periphery of the inclusion in cells infected by wild-type or ct288 mutant C. trachomatis. This suggests a model in which chlamydial proteins other than CT288 recruit CCDC146 to the periphery of the inclusion, where the CT288-CCDC146 interaction might contribute to modulate the function of this host protein.
Collapse
Affiliation(s)
- Filipe Almeida
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Maria P Luís
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal
| | - Inês Serrano Pereira
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal
| | - Sara V Pais
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal
| | - Luís Jaime Mota
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| |
Collapse
|
28
|
Allgood SC, Neunuebel MR. The recycling endosome and bacterial pathogens. Cell Microbiol 2018; 20:e12857. [PMID: 29748997 PMCID: PMC5993623 DOI: 10.1111/cmi.12857] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 04/05/2018] [Accepted: 04/27/2018] [Indexed: 12/29/2022]
Abstract
Bacterial pathogens have developed a wide range of strategies to survive within human cells. A number of pathogens multiply in a vacuolar compartment, whereas others can rupture the vacuole and replicate in the host cytosol. A common theme among many bacterial pathogens is the use of specialised secretion systems to deliver effector proteins into the host cell. These effectors can manipulate the host's membrane trafficking pathways to remodel the vacuole into a replication-permissive niche and prevent degradation. As master regulators of eukaryotic membrane traffic, Rab GTPases are principal targets of bacterial effectors. This review highlights the manipulation of Rab GTPases that regulate host recycling endocytosis by several bacterial pathogens, including Chlamydia pneumoniae, Chlamydia trachomatis, Shigella flexneri, Salmonella enterica serovar Typhimurium, Uropathogenic Escherichia coli, and Legionella pneumophila. Recycling endocytosis plays key roles in a variety of cellular aspects such as nutrient uptake, immunity, cell division, migration, and adhesion. Though much remains to be understood about the molecular basis and the biological relevance of bacterial pathogens exploiting Rab GTPases, current knowledge supports the notion that endocytic recycling Rab GTPases are differentially targeted to avoid degradation and support bacterial replication. Thus, future studies of the interactions between bacterial pathogens and host endocytic recycling pathways are poised to deepen our understanding of bacterial survival strategies.
Collapse
Affiliation(s)
| | - M. Ramona Neunuebel
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| |
Collapse
|
29
|
Mackern-Oberti JP, Motrich RD, Damiani MT, Saka HA, Quintero CA, Sánchez LR, Moreno-Sosa T, Olivera C, Cuffini C, Rivero VE. Male genital tract immune response against Chlamydia trachomatis infection. Reproduction 2018; 154:R99-R110. [PMID: 28878094 DOI: 10.1530/rep-16-0561] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 07/01/2017] [Accepted: 07/11/2017] [Indexed: 01/01/2023]
Abstract
Chlamydia trachomatis is the most commonly reported agent of sexually transmitted bacterial infections worldwide. This pathogen frequently leads to persistent, long-term, subclinical infections, which in turn may cause severe pathology in susceptible hosts. This is in part due to the strategies that Chlamydia trachomatis uses to survive within epithelial cells and to evade the host immune response, such as subverting intracellular trafficking, interfering signaling pathways and preventing apoptosis. Innate immune receptors such as toll-like receptors expressed on epithelial and immune cells in the genital tract mediate the recognition of chlamydial molecular patterns. After bacterial recognition, a subset of pro-inflammatory cytokines and chemokines are continuously released by epithelial cells. The innate immune response is followed by the initiation of the adaptive response against Chlamydia trachomatis, which in turn may result in T helper 1-mediated protection or in T helper 2-mediated immunopathology. Understanding the molecular mechanisms developed by Chlamydia trachomatis to avoid killing and host immune response would be crucial for designing new therapeutic approaches and developing protective vaccines. In this review, we focus on chlamydial survival strategies and the elicited immune responses in male genital tract infections.
Collapse
Affiliation(s)
- Juan Pablo Mackern-Oberti
- Instituto de Medicina y Biología Experimental de Cuyo. IMBECU-CONICETMendoza, Argentina .,Instituto de Fisiología. Facultad de Ciencias MédicasUniversidad Nacional de Cuyo, Mendoza, Argentina
| | - Rubén Darío Motrich
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Maria Teresa Damiani
- Instituto de Histología y Embriología de Mendoza. IHEM-CONICETFacultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Héctor Alex Saka
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | | | - Leonardo Rodolfo Sánchez
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Tamara Moreno-Sosa
- Instituto de Medicina y Biología Experimental de Cuyo. IMBECU-CONICETMendoza, Argentina
| | - Carolina Olivera
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Cecilia Cuffini
- Instituto de Virología Dr. J. M. VanellaFacultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Virginia Elena Rivero
- Centro de Investigaciones en Bioquímica Clínica e Inmunología CIBICI-CONICETDepartamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| |
Collapse
|
30
|
Absence of Specific Chlamydia trachomatis Inclusion Membrane Proteins Triggers Premature Inclusion Membrane Lysis and Host Cell Death. Cell Rep 2018; 19:1406-1417. [PMID: 28514660 DOI: 10.1016/j.celrep.2017.04.058] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/15/2017] [Accepted: 04/20/2017] [Indexed: 02/07/2023] Open
Abstract
Chlamydia trachomatis is a human pathogen associated with significant morbidity worldwide. As obligate intracellular parasites, chlamydiae must survive within eukaryotic cells for sufficient time to complete their developmental cycle. To promote host cell survival, chlamydiae express poorly understood anti-apoptotic factors. Using recently developed genetic tools, we show that three inclusion membrane proteins (Incs) out of eleven examined are required for inclusion membrane stability and avoidance of host cell death pathways. In the absence of specific Incs, premature inclusion lysis results in recognition by autophagolysosomes, activation of intrinsic apoptosis, and premature termination of the chlamydial developmental cycle. Inhibition of autophagy or knockdown of STING prevented host cell death and activation of intrinsic apoptosis. Significantly, these findings emphasize the importance of Incs in the establishment of a replicative compartment that sequesters the pathogen from host surveillance systems.
Collapse
|
31
|
Weber MM, Faris R. Subversion of the Endocytic and Secretory Pathways by Bacterial Effector Proteins. Front Cell Dev Biol 2018; 6:1. [PMID: 29417046 PMCID: PMC5787570 DOI: 10.3389/fcell.2018.00001] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 01/09/2018] [Indexed: 12/22/2022] Open
Abstract
Intracellular bacteria have developed numerous strategies to hijack host vesicular trafficking pathways to form their unique replicative niches. To promote intracellular replication, the bacteria must interact with host organelles and modulate host signaling pathways to acquire nutrients and membrane for the growing parasitophorous vacuole all while suppressing activation of the immune response. To facilitate host cell subversion, bacterial pathogens use specialized secretion systems to deliver bacterial virulence factors, termed effectors, into the host cell that mimic, agonize, and/or antagonize the function of host proteins. In this review we will discuss how bacterial effector proteins from Coxiella burnetii, Brucella abortus, Salmonella enterica serovar Typhimurium, Legionella pneumophila, Chlamydia trachomatis, and Orientia tsutsugamushi manipulate the endocytic and secretory pathways. Understanding how bacterial effector proteins manipulate host processes not only gives us keen insight into bacterial pathogenesis, but also enhances our understanding of how eukaryotic membrane trafficking is regulated.
Collapse
Affiliation(s)
- Mary M Weber
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States
| |
Collapse
|
32
|
Murray R, Flora E, Bayne C, Derré I. IncV, a FFAT motif-containing Chlamydia protein, tethers the endoplasmic reticulum to the pathogen-containing vacuole. Proc Natl Acad Sci U S A 2017; 114:12039-12044. [PMID: 29078338 PMCID: PMC5692559 DOI: 10.1073/pnas.1709060114] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membrane contact sites (MCS) are zones of contact between the membranes of two organelles. At MCS, specific proteins tether the organelles in close proximity and mediate the nonvesicular trafficking of lipids and ions between the two organelles. The endoplasmic reticulum (ER) integral membrane protein VAP is a common component of MCS involved in both tethering and lipid transfer by binding directly to proteins containing a FFAT [two phenylalanines (FF) in an acidic tract (AT)] motif. In addition to maintaining cell homeostasis, MCS formation recently emerged as a mechanism by which intracellular pathogens hijack cellular resources and establish their replication niche. Here, we investigated the mechanism by which the Chlamydia-containing vacuole, termed the inclusion, establishes direct contact with the ER. We show that the Chlamydia protein IncV, which is inserted into the inclusion membrane, displays one canonical and one noncanonical FFAT motif that cooperatively mediated the interaction of IncV with VAP. IncV overexpression was sufficient to bring the ER in close proximity of IncV-containing membranes. Although IncV deletion partially decreased VAP association with the inclusion, it did not suppress the formation of ER-inclusion MCS, suggesting the existence of redundant mechanisms in MCS formation. We propose a model in which IncV acts as one of the primary tethers that contribute to the formation of ER-inclusion MCS. Our results highlight a previously unidentified mechanism of bacterial pathogenesis and support the notion that cooperation of two FFAT motifs may be a common feature of VAP-mediated MCS formation. Chlamydia-host cell interaction therefore constitutes a unique system to decipher the molecular mechanisms underlying MCS formation.
Collapse
Affiliation(s)
- Rebecca Murray
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| | - Elizabeth Flora
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| | - Charlie Bayne
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| |
Collapse
|
33
|
Bhattacharya T, Newton ILG. Mi Casa es Su Casa: how an intracellular symbiont manipulates host biology. Environ Microbiol 2017; 21:10.1111/1462-2920.13964. [PMID: 29076641 PMCID: PMC5924462 DOI: 10.1111/1462-2920.13964] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/16/2017] [Accepted: 10/19/2017] [Indexed: 12/17/2022]
Abstract
Wolbachia pipientis, the most common intracellular infection on the planet, infects 40% of insects as well as nematodes, isopods and arachnids. Wolbachia are obligately intracellular and challenging to study; there are no genetic tools for manipulating Wolbachia nor can they be cultured outside of host cells. Despite these roadblocks, the research community has defined a set of Wolbachia loci involved in host interaction: Wolbachia effectors. Through the use of Drosophila genetics, surrogate systems and biochemistry, the field has begun to define the toolkit Wolbachia use for host manipulation. Below we review recent findings identifying these Wolbachia effectors and point to potential, as yet uncharacterized, links between known phenotypes induced by Wolbachia infection and predicted effectors.
Collapse
Affiliation(s)
| | - Irene L G Newton
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| |
Collapse
|
34
|
Acquisition of Rab11 and Rab11-Fip2-A novel strategy for Chlamydia pneumoniae early survival. PLoS Pathog 2017; 13:e1006556. [PMID: 28787457 PMCID: PMC5560749 DOI: 10.1371/journal.ppat.1006556] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 08/17/2017] [Accepted: 07/27/2017] [Indexed: 11/30/2022] Open
Abstract
The initial steps in chlamydial infection involve adhesion and internalization into host cells and, most importantly, modification of the nascent inclusion to establish the intracellular niche. Here, we show that Chlamydia pneumoniae enters host cells via EGFR-dependent endocytosis into an early endosome with a phosphatidylinositol 3-phosphate (PI3P) membrane identity. Immediately after entry, the early chlamydial inclusion acquires early endosomal Rab GTPases including Rab4, Rab5, Rab7, as well as the two recycling-specific Rabs Rab11 and Rab14. While Rab5, Rab11 and Rab14 are retained in the vesicular membrane, Rab4 and Rab7 soon disappear. Loss of Rab7 enables the C. pneumoniae inclusion to escape delivery to, and degradation in lysosomes. Loss of Rab4 and retention of Rab11/ Rab14 designates the inclusion as a slowly recycling endosome—that is protected from degradation. Furthermore, we show that the Rab11/ Rab14 adaptor protein Rab11-Fip2 (Fip2) is recruited to the nascent inclusion upon internalization and retained in the membrane throughout infection. siRNA knockdown of Fip2 demonstrated that the protein is essential for internalization and infection, and expression of various deletion variants revealed that Fip2 regulates the intracellular positioning of the inclusion. Additionally, we show that binding to Rab11 and Fip2 recruits the unconventional actin motor protein myosin Vb to the early inclusion and that together they regulate the relocation of the nascent inclusion from the cell periphery to the perinuclear region, its final destination. Here, we characterize for the first time inclusion identity and inclusion-associated proteins to delineate how C. pneumoniae establishes the intracellular niche essential for its survival. Here, we show for the first time how Chlamydia pneumoniae an obligate intracellular pathogen establishes its intracellular niche. After EGFR-dependent endocytosis into host cells, the nascent chlamydial inclusion acquires early endosomal membrane identity and the Rab GTPases Rab4, Rab5 and Rab7, as well as the recycling-specific Rab11 and Rab14. We show that Rab5, Rab11 and Rab14 are retained in the vesicular membrane, while Rab4 and Rab7 subsequently disappear. Thus, C. pneumoniae escapes lysosomal degradation by hiding in a recycling endosome vesicle. Furthermore, we show that the Rab11/Rab14 adaptor protein Rab11-Fip2 (Fip2), together with the unconventional actin motor protein myosin Vb, is recruited to the nascent inclusion. Both are essential for internalization and infection, as they regulate the intracellular positioning of the inclusion, which is essential for intracellular transport from the cell periphery to the perinuclear region. Here, we characterize for the first time inclusion identity and inclusion-associated proteins to understand how C. pneumoniae establishes the intracellular niche, which is essential for its survival.
Collapse
|
35
|
Koch-Edelmann S, Banhart S, Saied EM, Rose L, Aeberhard L, Laue M, Doellinger J, Arenz C, Heuer D. The cellular ceramide transport protein CERT promotes Chlamydia psittaci infection and controls bacterial sphingolipid uptake. Cell Microbiol 2017; 19. [PMID: 28544656 DOI: 10.1111/cmi.12752] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 05/15/2017] [Accepted: 05/15/2017] [Indexed: 01/04/2023]
Abstract
Chlamydiaceae are bacterial pathogens that cause diverse diseases in humans and animals. Despite their broad host and tissue tropism, all Chlamydia species share an obligate intracellular cycle of development and have evolved sophisticated mechanisms to interact with their eukaryotic host cells. Here, we have analysed interactions of the zoonotic pathogen Chlamydia psittaci with a human epithelial cell line. We found that C. psittaci recruits the ceramide transport protein (CERT) to its inclusion. Chemical inhibition and CRISPR/Cas9-mediated knockout of CERT showed that CERT is a crucial factor for C. psittaci infections thereby affecting different stages of the infection including inclusion growth and infectious progeny formation. Interestingly, the uptake of fluorescently labelled sphingolipids in bacteria inside the inclusion was accelerated in CERT-knockout cells indicating that C. psittaci can exploit CERT-independent sphingolipid uptake pathways. Moreover, the CERT-specific inhibitor HPA-12 strongly diminished sphingolipid transport to inclusions of infected CERT-knockout cells, suggesting that other HPA-12-sensitive factors are involved in sphingolipid trafficking to C. psittaci. Further analysis is required to decipher these interactions and to understand their contributions to bacterial development, host range, tissue tropism, and disease outcome.
Collapse
Affiliation(s)
- Sophia Koch-Edelmann
- Junior Research Group "Sexually Transmitted Bacterial Pathogens" (NG 5), Robert Koch Institute, Berlin, Germany
| | - Sebastian Banhart
- Junior Research Group "Sexually Transmitted Bacterial Pathogens" (NG 5), Robert Koch Institute, Berlin, Germany
| | - Essa M Saied
- Organic and Bioorganic Chemistry, Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany.,Chemistry Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Laura Rose
- Junior Research Group "Sexually Transmitted Bacterial Pathogens" (NG 5), Robert Koch Institute, Berlin, Germany
| | - Lukas Aeberhard
- Junior Research Group "Sexually Transmitted Bacterial Pathogens" (NG 5), Robert Koch Institute, Berlin, Germany
| | - Michael Laue
- Advanced Light and Electron Microscopy (ZBS 4), Robert Koch Institute, Berlin, Germany
| | - Joerg Doellinger
- Proteomics and Spectroscopy (ZBS 6), Robert Koch Institute, Berlin, Germany
| | - Christoph Arenz
- Organic and Bioorganic Chemistry, Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dagmar Heuer
- Junior Research Group "Sexually Transmitted Bacterial Pathogens" (NG 5), Robert Koch Institute, Berlin, Germany
| |
Collapse
|
36
|
O'Meara CP, Armitage CW, Andrew DW, Kollipara A, Lycke NY, Potter AA, Gerdts V, Petrovsky N, Beagley KW. Multistage vaccines containing outer membrane, type III secretion system and inclusion membrane proteins protects against a Chlamydia genital tract infection and pathology. Vaccine 2017; 35:3883-3888. [PMID: 28602608 DOI: 10.1016/j.vaccine.2017.05.063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 05/20/2017] [Accepted: 05/23/2017] [Indexed: 01/07/2023]
Abstract
Pathogens with a complex lifecycles can effectively evade host immunity in part due to each developmental stage expressing unique sets of antigens. Multisubunit vaccines incorporating signature antigens reflecting distinct developmental stages (multistage vaccines) have proven effective against viral, bacterial and parasitic infection at preventing pathogen evasion of host immunity. Chlamydia trachomatis is characterized by a biphasic extra/intracellular developmental cycle and an acute/persistent (latent) metabolic state; hence a multistage vaccine may prevent immune evasion and enhance clearance. Here we tested the efficacy of a multistage vaccine containing outer membrane (MOMP and PmpG), type three secretion system (T3SS) (CdsF and TC0873) and inclusion membrane proteins (IncA and TC0500) in mice against an intravaginal challenge with Chlamydia muridarum. Comparison of single (eg. MOMP) and double antigen vaccines (eg. MOMP and PmpG), largely targeting the extracellular stage, elicited significant yet comparable protection against vaginal shedding when compared to unimmunized control mice. Utilization of different adjuvants (ISCOMATRIX - IMX, PCEP/polyI:C/IDR1002 - VIDO, CTA1-DD and ADVAX) and numerous immunization routes (subcutaneous - SQ and intranasal - IN) further enhanced protection against infection. However, a multistage vaccine elicited significantly greater protection against vaginal shedding and upper genital tract pathology than vaccines targeting only extra- or intracellular stages. This indicates that protection elicited by a vaccine targeting extracellular chlamydial antigens could be improved by including chlamydial antigen expressed during intracellular phase.
Collapse
Affiliation(s)
- Connor P O'Meara
- Institute of Health and Biomedical Innovation (IHBI) and School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Queensland, Australia; Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Baden-Wüttemburg, Germany
| | - Charles W Armitage
- Institute of Health and Biomedical Innovation (IHBI) and School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - Dean W Andrew
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia
| | - Avinash Kollipara
- Institute of Health and Biomedical Innovation (IHBI) and School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Queensland, Australia
| | - Nils Y Lycke
- Mucosal Immunobiology and Vaccine Centre, University of Gothenburg, Sweden
| | - Andrew A Potter
- Vaccine and Infectious Disease Organization - International Vaccine Centre, University of Saskatchewan, Saskatoon, Canada
| | - Volker Gerdts
- Vaccine and Infectious Disease Organization - International Vaccine Centre, University of Saskatchewan, Saskatoon, Canada
| | - Nikolai Petrovsky
- Vaxine Pty Ltd, Adelaide, Australia; Department of Endocrinology, Flinders Medical Centre/Flinders University, Adelaide, Australia
| | - Kenneth W Beagley
- Institute of Health and Biomedical Innovation (IHBI) and School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Queensland, Australia.
| |
Collapse
|
37
|
Han Y, Derré I. A Co-infection Model System and the Use of Chimeric Proteins to Study Chlamydia Inclusion Proteins Interaction. Front Cell Infect Microbiol 2017; 7:79. [PMID: 28352612 PMCID: PMC5348484 DOI: 10.3389/fcimb.2017.00079] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/27/2017] [Indexed: 01/30/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium associated with trachoma and sexually transmitted diseases. During its intracellular developmental cycle, Chlamydia resides in a membrane bound compartment called the inclusion. A subset of Type III secreted effectors, the inclusion membrane proteins (Inc), are inserted into the inclusion membrane. Inc proteins are strategically positioned to promote inclusion interaction with host factors and organelles, a process required for bacterial replication, but little is known about Inc proteins function or host interacting partners. Moreover, it is unclear whether each Inc protein has a distinct function or if a subset of Inc proteins interacts with one another to perform their function. Here, we used IncD as a model to investigate Inc/Inc interaction in the context of Inc protein expression in C. trachomatis. We developed a co-infection model system to display different tagged Inc proteins on the surface of the same inclusion. We also designed chimeric Inc proteins to delineate domains important for interaction. We showed that IncD can self-interact and that the full-length protein is required for dimerization and/or oligomerization. Altogether our approach can be generalized to any Inc protein and will help to characterize the molecular mechanisms by which Chlamydia Inc proteins interact with themselves and/or host factors, eventually leading to a better understanding of C. trachomatis interaction with the mammalian host.
Collapse
Affiliation(s)
- Ying Han
- Department of Molecular Biophysics and Biochemistry, Yale University New Haven, CT, USA
| | - Isabelle Derré
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia Charlottesville, VA, USA
| |
Collapse
|
38
|
Paul B, Kim HS, Kerr MC, Huston WM, Teasdale RD, Collins BM. Structural basis for the hijacking of endosomal sorting nexin proteins by Chlamydia trachomatis. eLife 2017; 6. [PMID: 28226239 PMCID: PMC5348129 DOI: 10.7554/elife.22311] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 02/19/2017] [Indexed: 12/17/2022] Open
Abstract
During infection chlamydial pathogens form an intracellular membrane-bound replicative niche termed the inclusion, which is enriched with bacterial transmembrane proteins called Incs. Incs bind and manipulate host cell proteins to promote inclusion expansion and provide camouflage against innate immune responses. Sorting nexin (SNX) proteins that normally function in endosomal membrane trafficking are a major class of inclusion-associated host proteins, and are recruited by IncE/CT116. Crystal structures of the SNX5 phox-homology (PX) domain in complex with IncE define the precise molecular basis for these interactions. The binding site is unique to SNX5 and related family members SNX6 and SNX32. Intriguingly the site is also conserved in SNX5 homologues throughout evolution, suggesting that IncE captures SNX5-related proteins by mimicking a native host protein interaction. These findings thus provide the first mechanistic insights both into how chlamydial Incs hijack host proteins, and how SNX5-related PX domains function as scaffolds in protein complex assembly.
Collapse
Affiliation(s)
- Blessy Paul
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Hyun Sung Kim
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Markus C Kerr
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | | | - Rohan D Teasdale
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| |
Collapse
|
39
|
Rucks EA, Olson MG, Jorgenson LM, Srinivasan RR, Ouellette SP. Development of a Proximity Labeling System to Map the Chlamydia trachomatis Inclusion Membrane. Front Cell Infect Microbiol 2017; 7:40. [PMID: 28261569 PMCID: PMC5309262 DOI: 10.3389/fcimb.2017.00040] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 02/03/2017] [Indexed: 11/13/2022] Open
Abstract
Chlamydia grows within a membrane-bound vacuole termed an inclusion. The cellular processes that support the biogenesis and integrity of this pathogen-specified parasitic organelle are not understood. Chlamydia secretes integral membrane proteins called Incs that insert into the chlamydial inclusion membrane (IM). Incs contain at least two hydrophobic transmembrane domains flanked by termini, which vary in size and are exposed to the host cytosol. In addition, Incs are temporally expressed during the chlamydial developmental cycle. Data examining Inc function are limited because of (i) the difficulty in working with hydrophobic proteins and (ii) the inherent fragility of the IM. We hypothesize that Incs function collaboratively to maintain the integrity of the chlamydial inclusion with small Incs organizing the IM and larger Incs interfacing with host cell machinery. To study this hypothesis, we have adapted a proximity-labeling strategy using APEX2, a mutant soybean ascorbate peroxidase that biotinylates interacting and proximal proteins within minutes in the presence of H2O2 and its exogenous substrate, biotin-phenol. We successfully expressed, from an inducible background, APEX2 alone, or fusion proteins of IncATM (TM = transmembrane domain only), IncA, and IncF with APEX2 in Chlamydia trachomatis serovar L2. IncF-APEX2, IncA TM -APEX2, and IncA-APEX2 localized to the IM whereas APEX2, lacking a secretion signal, remained associated with the bacteria. We determined the impact of overexpression on inclusion diameter, plasmid stability, and Golgi-derived sphingomyelin acquisition. While there was an overall impact of inducing construct expression, IncF-APEX2 overexpression most negatively impacted these measurements. Importantly, Inc-APEX2 expression in the presence of biotin-phenol resulted in biotinylation of the IM. These data suggest that Inc expression is regulated to control optimal IM biogenesis. We subsequently defined lysis conditions that solubilized known Incs and were compatible with pulldown conditions. Importantly, we have created powerful tools to allow direct examination of the dynamic composition of the IM, which will provide novel insights into key interactions that promote chlamydial growth and development within the inclusion.
Collapse
Affiliation(s)
- Elizabeth A Rucks
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| | - Macy G Olson
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| | - Lisa M Jorgenson
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| | - Rekha R Srinivasan
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| | - Scot P Ouellette
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota Vermillion, SD, USA
| |
Collapse
|
40
|
Sixt BS, Bastidas RJ, Finethy R, Baxter RM, Carpenter VK, Kroemer G, Coers J, Valdivia RH. The Chlamydia trachomatis Inclusion Membrane Protein CpoS Counteracts STING-Mediated Cellular Surveillance and Suicide Programs. Cell Host Microbe 2017; 21:113-121. [PMID: 28041929 PMCID: PMC5233594 DOI: 10.1016/j.chom.2016.12.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/03/2016] [Accepted: 12/07/2016] [Indexed: 12/24/2022]
Abstract
Evading cell death is critical for Chlamydia to maintain a replicative niche, but the underlying mechanisms are unknown. We screened a library of Chlamydia mutants for modulators of cell death. Inactivation of the inclusion membrane protein CpoS (Chlamydia promoter of survival) induced rapid apoptotic and necrotic death in infected cells. The protection afforded by CpoS is limited to the inclusion in which it resides, indicating that it counteracts a spatially restricted pro-death signal. CpoS-deficient Chlamydia induced an exacerbated type I interferon response that required the host cGAS/STING/TBK1/IRF3 signaling pathway. Disruption of STING, but not cGAS or IRF3, attenuated cell death, suggesting that STING mediates Chlamydia-induced cell death independent of its role in regulating interferon responses. CpoS-deficient strains are attenuated in their ability to propagate in cell culture and are cleared faster from the murine genital tract, highlighting the importance of CpoS for Chlamydia pathogenesis.
Collapse
Affiliation(s)
- Barbara S Sixt
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA; INSERM U1138, Centre de Recherche des Cordeliers, Paris 75006, France; Equipe 11 labellisée Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris 75006, France; Université Paris Descartes, Paris 75006, France; Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif 94800, France
| | - Robert J Bastidas
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
| | - Ryan Finethy
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
| | - Ryan M Baxter
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
| | - Victoria K Carpenter
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
| | - Guido Kroemer
- INSERM U1138, Centre de Recherche des Cordeliers, Paris 75006, France; Equipe 11 labellisée Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris 75006, France; Université Paris Descartes, Paris 75006, France; Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif 94800, France; Pôle de Biologie, Hôpital Européen Georges-Pompidou, AP-HP, Paris 75015, France; Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital, Stockholm 17176, Sweden
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA; Department of Immunology, Duke University, Durham, NC 27710, USA
| | - Raphael H Valdivia
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA.
| |
Collapse
|
41
|
Abstract
Intracellular bacterial pathogens have evolved to exploit the protected niche provided within the boundaries of a eukaryotic host cell. Upon entering a host cell, some bacteria can evade the adaptive immune response of its host and replicate in a relatively nutrient-rich environment devoid of competition from other host flora. Growth within a host cell is not without their hazards, however. Many pathogens enter their hosts through receptor-mediated endocytosis or phagocytosis, two intracellular trafficking pathways that terminate in a highly degradative organelle, the phagolysosome. This usually deadly compartment is maintained at a low pH and contains degradative enzymes and reactive oxygen species, resulting in an environment to which few bacterial species are adapted. Some intracellular pathogens, such as Shigella, Listeria, Francisella, and Rickettsia, escape the phagosome to replicate within the cytosol of the host cell. Bacteria that remain within a vacuole either alter the trafficking of their initial phagosomal compartment or adapt to survive within the harsh environment it will soon become. In this chapter, we focus on the mechanisms by which different vacuolar pathogens either evade lysosomal fusion, as in the case of Mycobacterium and Chlamydia, or allow interaction with lysosomes to varying degrees, such as Brucella and Coxiella, and their specific adaptations to inhabit a replicative niche.
Collapse
|
42
|
Fozo EM, Rucks EA. The Making and Taking of Lipids: The Role of Bacterial Lipid Synthesis and the Harnessing of Host Lipids in Bacterial Pathogenesis. Adv Microb Physiol 2016; 69:51-155. [PMID: 27720012 DOI: 10.1016/bs.ampbs.2016.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In order to survive environmental stressors, including those induced by growth in the human host, bacterial pathogens will adjust their membrane physiology accordingly. These physiological changes also include the use of host-derived lipids to alter their own membranes and feed central metabolic pathways. Within the host, the pathogen is exposed to many stressful stimuli. A resulting adaptation is for pathogens to scavenge the host environment for readily available lipid sources. The pathogen takes advantage of these host-derived lipids to increase or decrease the rigidity of their own membranes, to provide themselves with valuable precursors to feed central metabolic pathways, or to impact host signalling and processes. Within, we review the diverse mechanisms that both extracellular and intracellular pathogens employ to alter their own membranes as well as their use of host-derived lipids in membrane synthesis and modification, in order to increase survival and perpetuate disease within the human host. Furthermore, we discuss how pathogen employed mechanistic utilization of host-derived lipids allows for their persistence, survival and potentiation of disease. A more thorough understanding of all of these mechanisms will have direct consequences for the development of new therapeutics, and specifically, therapeutics that target pathogens, while preserving normal flora.
Collapse
Affiliation(s)
- E M Fozo
- University of Tennessee, Knoxville, TN, United States.
| | - E A Rucks
- Sanford School of Medicine, University of South Dakota, Vermillion, SD, United States.
| |
Collapse
|
43
|
Takeuchi H, Takada A, Kuboniwa M, Amano A. Intracellular periodontal pathogen exploits recycling pathway to exit from infected cells. Cell Microbiol 2016; 18:928-48. [PMID: 26617273 DOI: 10.1111/cmi.12551] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/09/2015] [Accepted: 11/23/2015] [Indexed: 01/09/2023]
Abstract
Although human gingival epithelium prevents intrusions by periodontal bacteria, Porphyromonas gingivalis, the most well-known periodontal pathogen, is able to invade gingival epithelial cells and pass through the epithelial barrier into deeper tissues. We previously reported that intracellular P. gingivalis exits from gingival epithelial cells via a recycling pathway. However, the underlying molecular process remains unknown. In the present study, we found that the pathogen localized in early endosomes recruits VAMP2 and Rab4A. VAMP2 was found to be specifically localized in early endosomes, although its localization remained unclear in mammalian cells. A single transmembrane domain of VAMP2 was found to be necessary and sufficient for localizing in early endosomes containing P. gingivalis in gingival epithelial cells. VAMP2 forms a complex with EXOC2/Sec5 and EXOC3/Sec6, whereas Rab4A mediates dissociation of the EXOC complex followed by recruitment of RUFY1/Rabip4, Rab4A effector, and Rab14. Depletion of VAMP2 or Rab4A resulted in accumulation of bacteria in early endosomes and disturbed bacterial exit from infected cells. It is suggested that these novel dynamics allow P. gingivalis to exploit fast recycling pathways promoting further bacterial penetration of gingival tissues.
Collapse
Affiliation(s)
- Hiroki Takeuchi
- Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita-Osaka, 565-0871, Japan
| | - Akihiko Takada
- Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita-Osaka, 565-0871, Japan
| | - Masae Kuboniwa
- Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita-Osaka, 565-0871, Japan
| | - Atsuo Amano
- Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita-Osaka, 565-0871, Japan
| |
Collapse
|
44
|
Abstract
The lifestyle of Chlamydiae is unique: the bacteria alternate between two morphologically distinct forms, an infectious non-replicative elementary body (EB), and a replicative, non-infectious reticulate body (RB). This review focuses on recent advances in understanding the structure and function of the infectious form of the best-studied member of the phylum, the human pathogen Chlamydia trachomatis. Once considered as an inert particle of little functional capacity, the EB is now perceived as a sophisticated entity that encounters at least three different environments during each infectious cycle. We review current knowledge on its composition and morphology, and emerging metabolic activities. These features confer resistance to the extracellular environment, the ability to penetrate a host cell and ultimately enable the EB to establish a niche enabling bacterial survival and growth. The bacterial and host molecules involved in these processes are beginning to emerge.
Collapse
|
45
|
Targeting of host organelles by pathogenic bacteria: a sophisticated subversion strategy. Nat Rev Microbiol 2015; 14:5-19. [PMID: 26594043 DOI: 10.1038/nrmicro.2015.1] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Many bacterial pathogens have evolved the ability to subvert and exploit host functions in order to enter and replicate in eukaryotic cells. For example, bacteria have developed specific mechanisms to target eukaryotic organelles such as the nucleus, the mitochondria, the endoplasmic reticulum and the Golgi apparatus. In this Review, we highlight the most recent advances in our understanding of the mechanisms that bacterial pathogens use to target these organelles. We also discuss how these strategies allow bacteria to manipulate host functions and to ultimately enable bacterial infection.
Collapse
|
46
|
Expression and localization of predicted inclusion membrane proteins in Chlamydia trachomatis. Infect Immun 2015; 83:4710-8. [PMID: 26416906 DOI: 10.1128/iai.01075-15] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/16/2015] [Indexed: 11/20/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen that replicates in a membrane-bound vacuole termed the inclusion. Early in the infection cycle, the pathogen extensively modifies the inclusion membrane through incorporation of numerous type III secreted effector proteins, called inclusion membrane proteins (Incs). These proteins are characterized by a bilobed hydrophobic domain of 40 amino acids. The presence of this domain has been used to predict up to 59 putative Incs for C. trachomatis; however, localization to the inclusion membrane with specific antibodies has been demonstrated for only about half of them. Here, we employed recently developed genetic tools to verify the localization of predicted Incs that had not been previously localized to the inclusion membrane. Expression of epitope-tagged putative Incs identified 10 that were previously unverified as inclusion membrane localized and thus authentic Incs. One novel Inc and 3 previously described Incs were localized to inclusion membrane microdomains, as evidenced by colocalization with phosphorylated Src (p-Src). Several predicted Incs did not localize to the inclusion membrane but instead remained associated with the bacteria. Using Yersinia as a surrogate host, we demonstrated that many of these are not secreted via type III secretion, further suggesting they may not be true Incs. Collectively, our results highlight the utility of genetic tools for demonstrating secretion from chlamydia. Further mechanistic studies aimed at elucidating effector function will advance our understanding of how the pathogen maintains its unique intracellular niche and mediates interactions with the host.
Collapse
|
47
|
Dumoux M, Menny A, Delacour D, Hayward RD. A Chlamydia effector recruits CEP170 to reprogram host microtubule organization. J Cell Sci 2015. [PMID: 26220855 PMCID: PMC4582400 DOI: 10.1242/jcs.169318] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The obligate intracellular bacterial pathogen Chlamydia trachomatis deploys virulence effectors to subvert host cell functions enabling its replication within a specialized membrane-bound compartment termed an inclusion. The control of the host cytoskeleton is crucial for Chlamydia uptake, inclusion biogenesis and cell exit. Here, we demonstrate how a Chlamydia effector rearranges the microtubule (MT) network by initiating organization of the MTs at the inclusion surface. We identified an inclusion-localized effector that is sufficient to interfere with MT assembly, which we named inclusion protein acting on MTs (IPAM). We established that IPAM recruits and stimulates the centrosomal protein 170 kDa (CEP170) to hijack the MT organizing functions of the host cell. We show that CEP170 is essential for chlamydial control of host MT assembly, and is required for inclusion morphogenesis and bacterial infectivity. Together, we demonstrate how a pathogen effector reprograms the host MT network to support its intracellular development.
Collapse
Affiliation(s)
- Maud Dumoux
- Institute of Structural and Molecular Biology, Birkbeck and University College London, Malet Street, London WC1E 7HX, UK
| | - Anais Menny
- Institute of Structural and Molecular Biology, Birkbeck and University College London, Malet Street, London WC1E 7HX, UK
| | - Delphine Delacour
- Cell Adhesion and Mechanics Group, Institut Jacques Monod, CNRS UMR7592, Université Paris Diderot, 15 rue Helene Brion, Paris 75013, France
| | - Richard D Hayward
- Institute of Structural and Molecular Biology, Birkbeck and University College London, Malet Street, London WC1E 7HX, UK
| |
Collapse
|
48
|
Gambarte Tudela J, Capmany A, Romao M, Quintero C, Miserey-Lenkei S, Raposo G, Goud B, Damiani MT. The late endocytic Rab39a GTPase regulates the interaction between multivesicular bodies and chlamydial inclusions. J Cell Sci 2015; 128:3068-81. [PMID: 26163492 DOI: 10.1242/jcs.170092] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 07/06/2015] [Indexed: 01/31/2023] Open
Abstract
Given their obligate intracellular lifestyle, Chlamydia trachomatis ensure that they have access to multiple host sources of essential lipids by interfering with vesicular transport. These bacteria hijack Rab6-, Rab11- and Rab14-controlled trafficking pathways to acquire sphingomyelin from the Golgi complex. Another important source of sphingolipids, phospholipids and cholesterol are multivesicular bodies (MVBs). Despite their participation in chlamydial inclusion development and bacterial replication, the molecular mechanisms mediating the interaction between MVBs and chlamydial inclusions remain unknown. In the present study, we demonstrate that Rab39a labels a subset of late endocytic vesicles - mainly MVBs - that move along microtubules. Moreover, Rab39a is actively recruited to chlamydial inclusions throughout the pathogen life cycle by a bacterial-driven process that depends on the Rab39a GTP- or GDP-binding state. Interestingly, Rab39a participates in the delivery of MVBs and host sphingolipids to maturing chlamydial inclusions, thereby promoting inclusion growth and bacterial development. Taken together, our findings indicate that Rab39a favours chlamydial replication and infectivity. This is the first report showing that a late endocytic Rab GTPase is involved in chlamydial infection development.
Collapse
Affiliation(s)
- Julian Gambarte Tudela
- Laboratory of Phagocytosis and Intracellular Transport, School of Medicine, University of Cuyo, IHEM-CONICET, Mendoza 5500, Argentina
| | - Anahi Capmany
- Laboratory of Phagocytosis and Intracellular Transport, School of Medicine, University of Cuyo, IHEM-CONICET, Mendoza 5500, Argentina
| | - Maryse Romao
- Structure and Membrane Compartments, Cell and Tissue Imaging Facility, CNRS UMR144, Curie Institute, Paris 75248, France
| | - Cristian Quintero
- Laboratory of Phagocytosis and Intracellular Transport, School of Medicine, University of Cuyo, IHEM-CONICET, Mendoza 5500, Argentina
| | | | - Graca Raposo
- Structure and Membrane Compartments, Cell and Tissue Imaging Facility, CNRS UMR144, Curie Institute, Paris 75248, France
| | - Bruno Goud
- Molecular Mechanisms of Intracellular Transport, CNRS UMR144, Curie Institute, Paris, France
| | - Maria Teresa Damiani
- Laboratory of Phagocytosis and Intracellular Transport, School of Medicine, University of Cuyo, IHEM-CONICET, Mendoza 5500, Argentina
| |
Collapse
|
49
|
Mirrashidi KM, Elwell CA, Verschueren E, Johnson JR, Frando A, Von Dollen J, Rosenberg O, Gulbahce N, Jang G, Johnson T, Jäger S, Gopalakrishnan AM, Sherry J, Dunn JD, Olive A, Penn B, Shales M, Cox JS, Starnbach MN, Derre I, Valdivia R, Krogan NJ, Engel J. Global Mapping of the Inc-Human Interactome Reveals that Retromer Restricts Chlamydia Infection. Cell Host Microbe 2015; 18:109-21. [PMID: 26118995 DOI: 10.1016/j.chom.2015.06.004] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/28/2015] [Accepted: 06/05/2015] [Indexed: 01/02/2023]
Abstract
Chlamydia trachomatis is a leading cause of genital and ocular infections for which no vaccine exists. Upon entry into host cells, C. trachomatis resides within a membrane-bound compartment—the inclusion—and secretes inclusion membrane proteins (Incs) that are thought to modulate the host-bacterium interface. To expand our understanding of Inc function(s), we subjected putative C. trachomatis Incs to affinity purification-mass spectroscopy (AP-MS). We identified Inc-human interactions for 38/58 Incs with enrichment in host processes consistent with Chlamydia's intracellular life cycle. There is significant overlap between Inc targets and viral proteins, suggesting common pathogenic mechanisms among obligate intracellular microbes. IncE binds to sorting nexins (SNXs) 5/6, components of the retromer, which relocalizes SNX5/6 to the inclusion membrane and augments inclusion membrane tubulation. Depletion of retromer components enhances progeny production, revealing that retromer restricts Chlamydia infection. This study demonstrates the value of proteomics in unveiling host-pathogen interactions in genetically challenging microbes.
Collapse
Affiliation(s)
- Kathleen M Mirrashidi
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Cherilyn A Elwell
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Erik Verschueren
- QB3, California Institute for Quantitative Biosciences, San Francisco, CA 94148, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jeffrey R Johnson
- QB3, California Institute for Quantitative Biosciences, San Francisco, CA 94148, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Andrew Frando
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - John Von Dollen
- QB3, California Institute for Quantitative Biosciences, San Francisco, CA 94148, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Oren Rosenberg
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Natali Gulbahce
- QB3, California Institute for Quantitative Biosciences, San Francisco, CA 94148, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Gwendolyn Jang
- QB3, California Institute for Quantitative Biosciences, San Francisco, CA 94148, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Tasha Johnson
- QB3, California Institute for Quantitative Biosciences, San Francisco, CA 94148, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Stefanie Jäger
- QB3, California Institute for Quantitative Biosciences, San Francisco, CA 94148, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | | | - Jessica Sherry
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Joe Dan Dunn
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
| | - Andrew Olive
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Bennett Penn
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Michael Shales
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Gladstone Institutes, San Francisco, CA 94158, USA
| | - Jeffery S Cox
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | | | - Isabelle Derre
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA
| | - Raphael Valdivia
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
| | - Nevan J Krogan
- QB3, California Institute for Quantitative Biosciences, San Francisco, CA 94148, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Gladstone Institutes, San Francisco, CA 94158, USA.
| | - Joanne Engel
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA.
| |
Collapse
|
50
|
Borges V, Gomes JP. Deep comparative genomics among Chlamydia trachomatis lymphogranuloma venereum isolates highlights genes potentially involved in pathoadaptation. INFECTION GENETICS AND EVOLUTION 2015; 32:74-88. [PMID: 25745888 DOI: 10.1016/j.meegid.2015.02.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/23/2015] [Accepted: 02/26/2015] [Indexed: 11/19/2022]
Abstract
Lymphogranuloma venereum (LGV) is a human sexually transmitted disease caused by the obligate intracellular bacterium Chlamydia trachomatis (serovars L1-L3). LGV clinical manifestations range from severe ulcerative proctitis (anorectal syndrome), primarily caused by the epidemic L2b strains, to painful inguinal lymphadenopathy (the typical LGV bubonic form). Besides potential host-related factors, the differential disease severity and tissue tropism among LGV strains is likely a function of the genetic backbone of the strains. We aimed to characterize the genetic variability among LGV strains as strain- or serovar-specific mutations may underlie phenotypic signatures, and to investigate the mutational events that occurred throughout the pathoadaptation of the epidemic L2b lineage. By analyzing 20 previously published genomes from L1, L2, L2b and L3 strains and two new genomes from L2b strains, we detected 1497 variant sites and about 100 indels, affecting 453 genes and 144 intergenic regions, with 34 genes displaying a clear overrepresentation of nonsynonymous mutations. Effectors and/or type III secretion substrates (almost all of those described in the literature) and inclusion membrane proteins showed amino acid changes that were about fivefold more frequent than silent changes. More than 120 variant sites occurred in plasmid-regulated virulence genes, and 66% yielded amino acid changes. The identified serovar-specific variant sites revealed that the L2b-specific mutations are likely associated with higher fitness and pointed out potential targets for future highly discriminatory diagnostic/typing tests. By evaluating the evolutionary pathway beyond the L2b clonal radiation, we observed that 90.2% of the intra-L2b variant sites occurring in coding regions involve nonsynonymous mutations, where CT456/tarp has been the main target. Considering the progress on C. trachomatis genetic manipulation, this study may constitute an important contribution for prioritizing study targets for functional genomics aiming to dissect the impact of the identified intra-LGV polymorphisms on virulence or tropism dissimilarities among LGV strains.
Collapse
Affiliation(s)
- Vítor Borges
- Reference Laboratory of Bacterial Sexually Transmitted Infections, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - João Paulo Gomes
- Reference Laboratory of Bacterial Sexually Transmitted Infections, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal; Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
| |
Collapse
|