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The Small Molecule H89 Inhibits Chlamydia Inclusion Growth and Production of Infectious Progeny. Infect Immun 2021; 89:e0072920. [PMID: 33820812 PMCID: PMC8373235 DOI: 10.1128/iai.00729-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Chlamydia is an obligate intracellular bacterium and the most common reportable cause of human infection in the United States. This pathogen proliferates inside a eukaryotic host cell, where it resides within a membrane-bound compartment called the chlamydial inclusion. It has an unusual developmental cycle, marked by conversion between a replicating form, the reticulate body (RB), and an infectious form, the elementary body (EB). We found that the small molecule H89 slowed inclusion growth and decreased overall RB replication by 2-fold but caused a 25-fold reduction in infectious EBs. This disproportionate effect on EB production was mainly due to a defect in RB-to-EB conversion and not to the induction of chlamydial persistence, which is an altered growth state. Although H89 is a known inhibitor of specific protein kinases and vesicular transport to and from the Golgi apparatus, it did not cause these anti-chlamydial effects by blocking protein kinase A or C or by inhibiting protein or lipid transport. Thus, H89 is a novel anti-chlamydial compound that has a unique combination of effects on an intracellular Chlamydia infection.
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Keb G, Fields KA. An Ancient Molecular Arms Race: Chlamydia vs. Membrane Attack Complex/Perforin (MACPF) Domain Proteins. Front Immunol 2020; 11:1490. [PMID: 32760406 PMCID: PMC7371996 DOI: 10.3389/fimmu.2020.01490] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/08/2020] [Indexed: 12/16/2022] Open
Abstract
Dynamic interactions that govern the balance between host and pathogen determine the outcome of infection and are shaped by evolutionary pressures. Eukaryotic hosts have evolved elaborate and formidable defense mechanisms that provide the basis for innate and adaptive immunity. Proteins containing a membrane attack complex/Perforin (MACPF) domain represent an important class of immune effectors. These pore-forming proteins induce cell killing by targeting microbial or host membranes. Intracellular bacteria can be shielded from MACPF-mediated killing, and Chlamydia spp. represent a successful paradigm of obligate intracellular parasitism. Ancestors of present-day Chlamydia likely originated at evolutionary times that correlated with or preceded many host defense pathways. We discuss the current knowledge regarding how chlamydiae interact with the MACPF proteins Complement C9, Perforin-1, and Perforin-2. Current evidence indicates a degree of resistance by Chlamydia to MACPF effector mechanisms. In fact, chlamydiae have acquired and adapted their own MACPF-domain protein to facilitate infection.
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Affiliation(s)
- Gabrielle Keb
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Kenneth A Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
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Banhart S, Rose L, Aeberhard L, Koch-Edelmann S, Heuer D. Chlamydia trachomatis and its interaction with the cellular retromer. Int J Med Microbiol 2017; 308:197-205. [PMID: 29122514 DOI: 10.1016/j.ijmm.2017.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/16/2017] [Accepted: 10/24/2017] [Indexed: 11/26/2022] Open
Abstract
Chlamydia trachomatis is an important human pathogen. This obligate intracellular bacterium grows inside the eukaryotic cell in a membrane-bound compartment, the inclusion. Recent global approaches describe the interactions of C. trachomatis with its host cell and indicate the inclusion is an intracellular trafficking hub embedded into the cellular vesicular trafficking pathways recruiting subunits of the retromer protein complex of the host cell. Here we review these recent developments in deciphering Chlamydia-host cell interactions with emphasis on the role of the retromer complex.
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Affiliation(s)
- Sebastian Banhart
- Division "Sexually Transmitted Bacterial Infections" (FG 19), Robert Koch Institute, Berlin, Germany
| | - Laura Rose
- Division "Sexually Transmitted Bacterial Infections" (FG 19), Robert Koch Institute, Berlin, Germany
| | - Lukas Aeberhard
- Division "Sexually Transmitted Bacterial Infections" (FG 19), Robert Koch Institute, Berlin, Germany
| | - Sophia Koch-Edelmann
- Division "Sexually Transmitted Bacterial Infections" (FG 19), Robert Koch Institute, Berlin, Germany
| | - Dagmar Heuer
- Division "Sexually Transmitted Bacterial Infections" (FG 19), Robert Koch Institute, Berlin, Germany.
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Oki AT, Huang B, Beyer AR, May LJ, Truchan HK, Walker NJ, Galloway NL, Borjesson DL, Carlyon JA. Anaplasma phagocytophilum APH0032 Is Exposed on the Cytosolic Face of the Pathogen-Occupied Vacuole and Co-opts Host Cell SUMOylation. Front Cell Infect Microbiol 2016; 6:108. [PMID: 27713867 PMCID: PMC5031783 DOI: 10.3389/fcimb.2016.00108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/05/2016] [Indexed: 12/31/2022] Open
Abstract
Anaplasma phagocytophilum, a member of the family Anaplasmataceae and the obligate intracellular bacterium that causes granulocytic anaplasmosis, resides in a host cell-derived vacuole. Bacterial proteins that localize to the A. phagocytophilum-occupied vacuole membrane (AVM) are critical host-pathogen interfaces. Of the few bacterial AVM proteins that have been identified, the domains responsible for AVM localization and the host cell pathways that they co-opt are poorly defined. APH0032 is an effector that is expressed and localizes to the AVM late during the infection cycle. Herein, the APH0032 domain that is essential for associating with host cell membranes was mapped. Immunofluorescent labeling of infected cells that had been differentially permeabilized confirmed that APH0032 is exposed on the AVM's cytosolic face, signifying its potential to interface with host cell processes. SUMOylation is the covalent attachment of a member of the small ubiquitin-like modifier (SUMO) family of proteins to lysines in target substrates. Previous work from our laboratory determined that SUMOylation is important for A. phagocytophilum survival and that SUMOylated proteins decorate the AVM. Algorithmic prediction analyses identified APH0032 as a candidate for SUMOylation. Endogenous APH0032 was precipitated from infected cells using a SUMO affinity matrix, confirming that the effector co-opts SUMOylation during infection. APH0032 pronouncedly colocalized with SUMO1, but not SUMO2/3 moieties on the AVM. Ectopic expression of APH0032 in A. phagocytophilum infected host cells significantly boosted the bacterial load. This study delineates the first domain of any Anaplasmataceae protein that is essential for associating with the pathogen-occupied vacuole membrane, demonstrates the importance of APH0032 to infection, and identifies it as the second A. phagocytophilum effector that co-opts SUMOylation, thus underscoring the relevance of this post-translational modification to infection.
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Affiliation(s)
- Aminat T Oki
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine Richmond, VA, USA
| | - Bernice Huang
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine Richmond, VA, USA
| | - Andrea R Beyer
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine Richmond, VA, USA
| | - Levi J May
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine Richmond, VA, USA
| | - Hilary K Truchan
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine Richmond, VA, USA
| | - Naomi J Walker
- Department of Pathology, Microbiology, and Immunology, University of California School of Veterinary Medicine Davis, CA, USA
| | - Nathan L Galloway
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine Richmond, VA, USA
| | - Dori L Borjesson
- Department of Pathology, Microbiology, and Immunology, University of California School of Veterinary Medicine Davis, CA, USA
| | - Jason A Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine Richmond, VA, USA
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Soupene E, Rothschild J, Kuypers FA, Dean D. Eukaryotic protein recruitment into the Chlamydia inclusion: implications for survival and growth. PLoS One 2012; 7:e36843. [PMID: 22590624 PMCID: PMC3348897 DOI: 10.1371/journal.pone.0036843] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 04/16/2012] [Indexed: 11/28/2022] Open
Abstract
Chlamydia trachomatis (Ct) is an obligate intracellular human pathogen that multiplies within a parasitophorous vacuole called an inclusion. We report that the location of several host-cell proteins present in the cytosol, the nucleus, and membranes was altered during Ct development. The acyl-CoA synthetase enzyme ACSL3 and the soluble acyl-CoA binding protein ACBD6 were mobilized from organelle membranes and the nucleus, respectively, into the lumen of the inclusion. The nuclear protein ZNF23, a pro-apoptosis factor, was also translocated into the inclusion lumen. ZNF23, among other proteins, might be targeted by Ct to inhibit host cell apoptosis, thereby enabling bacterial survival. In contrast, the acyl-CoA:lysophosphatidylcholine acyltransferase LPCAT1, an endoplasmic reticulum membrane protein, was recruited to the inclusion membrane. The coordinated action of ACBD6, ACSL3 and LPCAT1 likely supports remodeling and scavenging of host lipids into bacterial-specific moieties essential to Ct growth. To our knowledge, these are the first identified host proteins known to be intercepted and translocated into the inclusion.
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Affiliation(s)
- Eric Soupene
- Center for Sickle Cell Disease and Thalassemia, Children's Hospital Oakland Research Institute, Oakland, California, United States of America.
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Flotillin-1 (Reggie-2) contributes to Chlamydia pneumoniae growth and is associated with bacterial inclusion. Infect Immun 2012; 80:1072-8. [PMID: 22215737 DOI: 10.1128/iai.05528-11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Chlamydiae are obligate intracellular pathogens replicating only inside the eukaryotic host. Here, we studied the effect of human flotillin-1 protein on Chlamydia pneumoniae growth in human line (HL) and A549 epithelial cell lines. RNA interference was applied to disrupt flotillin-1-mediated endocytosis. Host-associated bacteria were detected by quantitative PCR, and C. pneumoniae growth was evaluated by inclusion counts. C. pneumoniae attachment to host cells was unaffected, but bacterial intracellular growth was attenuated in the flotillin-1-silenced cells. By using confocal microscopy, we detected flotillin-1 colocalized with the inclusion membrane protein A (IncA) in the C. pneumoniae inclusion membranes. In addition, flotillin-1 was associated with IncA in detergent-resistant membrane microdomains (DRMs) in biochemical fractioning. These results suggest that flotillin-1 localizes to the C. pneumoniae inclusion membrane and plays an important role for intracellular growth of C. pneumoniae.
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Carter C. Alzheimer's Disease: APP, Gamma Secretase, APOE, CLU, CR1, PICALM, ABCA7, BIN1, CD2AP, CD33, EPHA1, and MS4A2, and Their Relationships with Herpes Simplex, C. Pneumoniae, Other Suspect Pathogens, and the Immune System. Int J Alzheimers Dis 2011; 2011:501862. [PMID: 22254144 PMCID: PMC3255168 DOI: 10.4061/2011/501862] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 09/02/2011] [Indexed: 12/26/2022] Open
Abstract
Alzheimer's disease susceptibility genes, APP and gamma-secretase, are involved in the herpes simplex life cycle, and that of other suspect pathogens (C. pneumoniae, H. pylori, C. neoformans, B. burgdorferri, P. gingivalis) or immune defence. Such pathogens promote beta-amyloid deposition and tau phosphorylation and may thus be causative agents, whose effects are conditioned by genes. The antimicrobial effects of beta-amyloid, the localisation of APP/gamma-secretase in immunocompetent dendritic cells, and gamma secretase cleavage of numerous pathogen receptors suggest that this network is concerned with pathogen disposal, effects which may be abrogated by the presence of beta-amyloid autoantibodies in the elderly. These autoantibodies, as well as those to nerve growth factor and tau, also observed in Alzheimer's disease, may well be antibodies to pathogens, due to homology between human autoantigens and pathogen proteins. NGF or tau antibodies promote beta-amyloid deposition, neurofibrillary tangles, or cholinergic neuronal loss, and, with other autoantibodies, such as anti-ATPase, are potential agents of destruction, whose formation is dictated by sequence homology between pathogen and human proteins, and thus by pathogen strain and human genes. Pathogen elimination in the ageing population and removal of culpable autoantibodies might reduce the incidence and offer hope for a cure in this affliction.
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Affiliation(s)
- Chris Carter
- PolygenicPathways, Flat 2, 40 Baldslow Road, Hastings, East Sussex TN34 2EY, UK
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Dehoux P, Flores R, Dauga C, Zhong G, Subtil A. Multi-genome identification and characterization of chlamydiae-specific type III secretion substrates: the Inc proteins. BMC Genomics 2011; 12:109. [PMID: 21324157 PMCID: PMC3048545 DOI: 10.1186/1471-2164-12-109] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 02/16/2011] [Indexed: 12/13/2022] Open
Abstract
Background Chlamydiae are obligate intracellular bacteria that multiply in a vacuolar compartment, the inclusion. Several chlamydial proteins containing a bilobal hydrophobic domain are translocated by a type III secretion (TTS) mechanism into the inclusion membrane. They form the family of Inc proteins, which is specific to this phylum. Based on their localization, Inc proteins likely play important roles in the interactions between the microbe and the host. In this paper we sought to identify and analyze, using bioinformatics tools, all putative Inc proteins in published chlamydial genomes, including an environmental species. Results Inc proteins contain at least one bilobal hydrophobic domain made of two transmembrane helices separated by a loop of less than 30 amino acids. Using bioinformatics tools we identified 537 putative Inc proteins across seven chlamydial proteomes. The amino-terminal segment of the putative Inc proteins was recognized as a functional TTS signal in 90% of the C. trachomatis and C. pneumoniae sequences tested, validating the data obtained in silico. We identified a macro domain in several putative Inc proteins, and observed that Inc proteins are enriched in segments predicted to form coiled coils. A surprisingly large proportion of the putative Inc proteins are not constitutively translocated to the inclusion membrane in culture conditions. Conclusions The Inc proteins represent 7 to 10% of each proteome and show a great degree of sequence diversity between species. The abundance of segments with a high probability for coiled coil conformation in Inc proteins support the hypothesis that they interact with host proteins. While the large majority of Inc proteins possess a functional TTS signal, less than half may be constitutively translocated to the inclusion surface in some species. This suggests the novel finding that translocation of Inc proteins may be regulated by as-yet undetermined mechanisms.
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Affiliation(s)
- Pierre Dehoux
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, Paris, France
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Acquisition of nutrients by Chlamydiae: unique challenges of living in an intracellular compartment. Curr Opin Microbiol 2009; 13:4-10. [PMID: 20006538 DOI: 10.1016/j.mib.2009.11.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 11/14/2009] [Indexed: 12/22/2022]
Abstract
The Chlamydiae are obligate intracellular pathogens that replicate within a membrane-bound vacuole, termed the 'inclusion'. From this compartment, bacteria acquire essential nutrients by selectively redirecting transport vesicles and hijacking intracellular organelles. Rerouting is achieved by several mechanisms including proteolysis-mediated fragmentation of the Golgi apparatus, recruitment of Rab GTPases and SNAREs, and translocation of cytoplasmic organelles into the inclusion lumen. Given Chlamydiae's extended coevolution with eukaryotic cells, it is likely that co-option of multiple cellular pathways is a strategy to provide redundancy in the acquisition of essential nutrients from the host and has contributed to the success of these highly adapted pathogens.
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