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North AJ, Sharma VP, Pyrgaki C, S Y JL, Atwal S, Saharat K, Wright GD, Salje J. A comparison of super-resolution microscopy techniques for imaging tightly packed microcolonies of an obligate intracellular bacterium. J Microsc 2024. [PMID: 39651611 DOI: 10.1111/jmi.13376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2024] [Revised: 11/19/2024] [Accepted: 11/20/2024] [Indexed: 12/11/2024]
Abstract
Conventional optical microscopy imaging of obligate intracellular bacteria is hampered by the small size of bacterial cells, tight clustering exhibited by some bacterial species and challenges relating to labelling such as background from host cells, a lack of validated reagents, and a lack of tools for genetic manipulation. In this study, we imaged intracellular bacteria from the species Orientia tsutsugamushi (Ot) using five different fluorescence microscopy techniques: standard confocal, Airyscan confocal, instant Structured Illumination Microscopy (iSIM), three-dimensional Structured Illumination Microscopy (3D-SIM) and Stimulated Emission Depletion Microscopy (STED). We compared the ability of each to resolve bacterial cells in intracellular clumps in the lateral (xy) axis, using full width half-maximum (FWHM) measurements of a labelled outer membrane protein (ScaA) and the ability to detect small, outer membrane vesicles external to the cells. Comparing the techniques readily available to us (above), 3D-SIM microscopy, in combination with the shortest-wavelength dyes, was found overall to give the best lateral resolution. We next compared the ability of each technique to sufficiently resolve bacteria in the axial (z) direction and found 3D-STED to be the most successful method for this. We then combined this 3D-STED approach with a custom 3D cell segmentation and analysis pipeline using the open-source, deep learning software, Cellpose to segment the cells and subsequently the commercial software Imaris to analyse their 3D shape and size. Using this combination, we demonstrated differences in bacterial shape, but not their size, when grown in different mammalian cell lines. Overall, we compare the advantages and disadvantages of different super-resolution microscopy techniques for imaging this cytoplasmic obligate intracellular bacterium based on the specific research question being addressed.
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Affiliation(s)
- Alison J North
- Bio-Imaging Resource Center, The Rockefeller University, New York, New York, USA
| | - Ved P Sharma
- Bio-Imaging Resource Center, The Rockefeller University, New York, New York, USA
| | - Christina Pyrgaki
- Bio-Imaging Resource Center, The Rockefeller University, New York, New York, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, USA
| | - John Lim S Y
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology & Research (A*STAR), Singapore, Singapore
| | | | - Kittirat Saharat
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Graham D Wright
- Research Support Centre (RSC), Agency for Science, Technology & Research (A*STAR), Singapore, Singapore
| | - Jeanne Salje
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Department of Pathology, University of Cambridge, Cambridge, UK
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2
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North AJ, Sharma VP, Pyrgaki C, Lim S Y J, Atwal S, Saharat K, Wright GD, Salje J. A comparison of super-resolution microscopy techniques for imaging tightly packed microcolonies of an obligate intracellular bacterium. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.12.607698. [PMID: 39211076 PMCID: PMC11361006 DOI: 10.1101/2024.08.12.607698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Conventional optical microscopy imaging of obligate intracellular bacteria is hampered by the small size of bacterial cells, tight clustering exhibited by some bacterial species and challenges relating to labelling such as background from host cells, a lack of validated reagents, and a lack of tools for genetic manipulation. In this study we imaged intracellular bacteria from the species Orientia tsutsugamushi (Ot) using five different fluorescence microscopy techniques: standard confocal, Airyscan confocal, instant Structured Illumination Microscopy (iSIM), three-dimensional Structured Illumination Microscopy (3D-SIM) and Stimulated Emission Depletion Microscopy (STED). We compared the ability of each to resolve bacterial cells in intracellular clumps in the lateral (xy) axis, using full width half maximum (FWHM) measurements of a labelled outer membrane protein (ScaA) and the ability to detect small, outer membrane vesicles external to the cells. We next compared the ability of each technique to sufficiently resolve bacteria in the axial (z) direction and found 3D-STED to be the most successful method for this. We then combined this approach with a custom 3D cell segmentation and analysis pipeline using the open-source, deep learning software, Cellpose to segment the cells and subsequently the commercial software Imaris to analyze their 3D shape and size. Using this combination, we demonstrated differences in bacterial shape, but not their size, when grown in different mammalian cell lines. Overall, we compare the advantages and disadvantages of different super-resolution microscopy techniques for imaging this cytoplasmic obligate intracellular bacterium based on the specific research question being addressed.
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3
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Hart TM, Sonnert ND, Tang X, Chaurasia R, Allen PE, Hunt JR, Read CB, Johnson EE, Arora G, Dai Y, Cui Y, Chuang YM, Yu Q, Rahman MS, Mendes MT, Rolandelli A, Singh P, Tripathi AK, Ben Mamoun C, Caimano MJ, Radolf JD, Lin YP, Fingerle V, Margos G, Pal U, Johnson RM, Pedra JHF, Azad AF, Salje J, Dimopoulos G, Vinetz JM, Carlyon JA, Palm NW, Fikrig E, Ring AM. An atlas of human vector-borne microbe interactions reveals pathogenicity mechanisms. Cell 2024; 187:4113-4127.e13. [PMID: 38876107 DOI: 10.1016/j.cell.2024.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 01/15/2024] [Accepted: 05/13/2024] [Indexed: 06/16/2024]
Abstract
Vector-borne diseases are a leading cause of death worldwide and pose a substantial unmet medical need. Pathogens binding to host extracellular proteins (the "exoproteome") represents a crucial interface in the etiology of vector-borne disease. Here, we used bacterial selection to elucidate host-microbe interactions in high throughput (BASEHIT)-a technique enabling interrogation of microbial interactions with 3,324 human exoproteins-to profile the interactomes of 82 human-pathogen samples, including 30 strains of arthropod-borne pathogens and 8 strains of related non-vector-borne pathogens. The resulting atlas revealed 1,303 putative interactions, including hundreds of pairings with potential roles in pathogenesis, including cell invasion, tissue colonization, immune evasion, and host sensing. Subsequent functional investigations uncovered that Lyme disease spirochetes recognize epidermal growth factor as an environmental cue of transcriptional regulation and that conserved interactions between intracellular pathogens and thioredoxins facilitate cell invasion. In summary, this interactome atlas provides molecular-level insights into microbial pathogenesis and reveals potential host-directed targets for next-generation therapeutics.
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Affiliation(s)
- Thomas M Hart
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Nicole D Sonnert
- Department of Immunobiology, Yale School of Medicine, New Haven, CT 06510, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA
| | - Xiaotian Tang
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Reetika Chaurasia
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Paige E Allen
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Jason R Hunt
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Curtis B Read
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Emily E Johnson
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Epidemiology and Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Gunjan Arora
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Yile Dai
- Department of Immunobiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Yingjun Cui
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Yu-Min Chuang
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Qian Yu
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - M Sayeedur Rahman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - M Tays Mendes
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Agustin Rolandelli
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Pallavi Singh
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Abhai K Tripathi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Choukri Ben Mamoun
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA
| | - Melissa J Caimano
- Department of Medicine, UConn Health, Farmington, CT 06030, USA; Department of Pediatrics, UConn Health, Farmington, CT 06030, USA; Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA
| | - Justin D Radolf
- Department of Medicine, UConn Health, Farmington, CT 06030, USA; Department of Pediatrics, UConn Health, Farmington, CT 06030, USA; Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA; Department of Genetics and Genome Sciences, UConn Health, Farmington, CT 06030, USA; Department of Immunology, UConn Health, Farmington, CT 06030, USA
| | - Yi-Pin Lin
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Volker Fingerle
- Bavarian Health and Food Safety Authority, Oberschleißheim, Munich 85764, Bavaria, Germany
| | - Gabriele Margos
- Bavarian Health and Food Safety Authority, Oberschleißheim, Munich 85764, Bavaria, Germany
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
| | - Raymond M Johnson
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA
| | - Joao H F Pedra
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Abdu F Azad
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jeanne Salje
- Department of Pathology, University of Cambridge, Cambridge CB2 1TN, UK; Department of Biochemistry, University of Cambridge, Cambridge CB2 1TN, UK
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Joseph M Vinetz
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Laboratorio ICEMR-Amazonia, Laboratorios de Investigación Y Desarrollo, Facultad de Ciencias Y Filosofia, Universidad Peruana Cayetano Heredia, Lima 15102, Peru; Instituto de Medicina Tropical Alexander Von Humboldt, Universidad Peruana Cayetano Heredia, Lima 15102, Peru
| | - Jason A Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
| | - Noah W Palm
- Department of Immunobiology, Yale School of Medicine, New Haven, CT 06510, USA.
| | - Erol Fikrig
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA.
| | - Aaron M Ring
- Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA 98102, USA.
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Srivastava P, Shukla A, Singh R, Kant R, Mishra N, Behera SP, Dwivedi GR, Yadav DK. Orientia tsutsugamushi: An Unusual Intracellular Bacteria-Adaptation Strategies, Available Antibiotics, and Alternatives for Treatment. Curr Microbiol 2024; 81:236. [PMID: 38907107 DOI: 10.1007/s00284-024-03754-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 05/28/2024] [Indexed: 06/23/2024]
Abstract
During evolution Orientia tsutsugamushi became a smarter obligate bacterium to establish as intracellular pathogens. O. tsutsugamushi is a human pathogenic bacterium responsible for 1 billion infections of scrub typhus. Several novel mechanisms make this bacterium unique (cell wall, genetic constitutions, secretion system, etc.). In 2007, O. tsutsugamushi Boryong was pioneer strain for whole-genome sequencing. But the fundamental biology of this bacterial cell is a mystery till date. The unusual biology makes this organism as model for host cell interaction. Only a few antibiotics are effective against this intracellular pathogen but emergence of less susceptibility toward antibiotics make the situation alarming. The review was captivated to highlight the unusual aspects of adaptation, antibiotics, and drugs beyond antibiotics.
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Affiliation(s)
- Prashansha Srivastava
- ICMR-Regional Medical Research Centre, BRD Medical College Campus, Gorakhpur, 273013, India
| | - Aishwarya Shukla
- ICMR-Regional Medical Research Centre, BRD Medical College Campus, Gorakhpur, 273013, India
| | - Rajeev Singh
- ICMR-Regional Medical Research Centre, BRD Medical College Campus, Gorakhpur, 273013, India
| | - Rajni Kant
- ICMR-Regional Medical Research Centre, BRD Medical College Campus, Gorakhpur, 273013, India
| | - Nalini Mishra
- ICMR-Regional Medical Research Centre, BRD Medical College Campus, Gorakhpur, 273013, India
| | - Sthita P Behera
- ICMR-Regional Medical Research Centre, BRD Medical College Campus, Gorakhpur, 273013, India
| | - Gaurav R Dwivedi
- ICMR-Regional Medical Research Centre, BRD Medical College Campus, Gorakhpur, 273013, India.
| | - Dharmendra K Yadav
- College of Pharmacy, Gachon University of Medicine and Science, Hambakmoeiro 191, Yeonsu-Gu, Incheon, 21924, Korea
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5
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Minahan NT, Yen TY, Guo YLL, Shu PY, Tsai KH. Concatenated ScaA and TSA56 Surface Antigen Sequences Reflect Genome-Scale Phylogeny of Orientia tsutsugamushi: An Analysis Including Two Genomes from Taiwan. Pathogens 2024; 13:299. [PMID: 38668254 PMCID: PMC11054523 DOI: 10.3390/pathogens13040299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 03/29/2024] [Accepted: 03/29/2024] [Indexed: 04/29/2024] Open
Abstract
Orientia tsutsugamushi is an obligate intracellular bacterium associated with trombiculid mites and is the causative agent of scrub typhus, a life-threatening febrile disease. Strain typing of O. tsutsugamushi is based on its immunodominant surface antigen, 56-kDa type-specific antigen (TSA56). However, TSA56 gene sequence-based phylogenetic analysis is only partially congruent with core genome-based phylogenetic analysis. Thus, this study investigated whether concatenated surface antigen sequences, including surface cell antigen (Sca) proteins, can reflect the genome-scale phylogeny of O. tsutsugamushi. Complete genomes were obtained for two common O. tsutsugamushi strains in Taiwan, TW-1 and TW-22, and the core genome/proteome was identified for 11 O. tsutsugamushi strains. Phylogenetic analysis was performed using maximum likelihood (ML) and neighbor-joining (NJ) methods, and the congruence between trees was assessed using a quartet similarity measure. Phylogenetic analysis based on 691 concatenated core protein sequences produced identical tree topologies with ML and NJ methods. Among TSA56 and core Sca proteins (ScaA, ScaC, ScaD, and ScaE), TSA56 trees were most similar to the core protein tree, and ScaA trees were the least similar. However, concatenated ScaA and TSA56 sequences produced trees that were highly similar to the core protein tree, the NJ tree being more similar. Strain-level characterization of O. tsutsugamushi may be improved by coanalyzing ScaA and TSA56 sequences, which are also important targets for their combined immunogenicity.
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Affiliation(s)
- Nicholas T. Minahan
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan; (N.T.M.); (Y.-L.L.G.)
| | - Tsai-Ying Yen
- Centers for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 115210, Taiwan; (T.-Y.Y.); (P.-Y.S.)
| | - Yue-Liang Leon Guo
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan; (N.T.M.); (Y.-L.L.G.)
- Department of Environmental and Occupational Medicine, National Taiwan University (NTU) College of Medicine and NTU Hospital, Taipei 100025, Taiwan
| | - Pei-Yun Shu
- Centers for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 115210, Taiwan; (T.-Y.Y.); (P.-Y.S.)
| | - Kun-Hsien Tsai
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 100025, Taiwan; (N.T.M.); (Y.-L.L.G.)
- Global Health Program, College of Public Health, National Taiwan University, Taipei 100025, Taiwan
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Fisher DJ, Beare PA. Recent advances in genetic systems in obligate intracellular human-pathogenic bacteria. Front Cell Infect Microbiol 2023; 13:1202245. [PMID: 37404720 PMCID: PMC10315504 DOI: 10.3389/fcimb.2023.1202245] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/22/2023] [Indexed: 07/06/2023] Open
Abstract
The ability to genetically manipulate a pathogen is fundamental to discovering factors governing host-pathogen interactions at the molecular level and is critical for devising treatment and prevention strategies. While the genetic "toolbox" for many important bacterial pathogens is extensive, approaches for modifying obligate intracellular bacterial pathogens were classically limited due in part to the uniqueness of their obligatory lifestyles. Many researchers have confronted these challenges over the past two and a half decades leading to the development of multiple approaches to construct plasmid-bearing recombinant strains and chromosomal gene inactivation and deletion mutants, along with gene-silencing methods enabling the study of essential genes. This review will highlight seminal genetic achievements and recent developments (past 5 years) for Anaplasma spp., Rickettsia spp., Chlamydia spp., and Coxiella burnetii including progress being made for the still intractable Orientia tsutsugamushi. Alongside commentary of the strengths and weaknesses of the various approaches, future research directions will be discussed to include methods for C. burnetii that should have utility in the other obligate intracellular bacteria. Collectively, the future appears bright for unraveling the molecular pathogenic mechanisms of these significant pathogens.
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Affiliation(s)
- Derek J. Fisher
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, United States
| | - Paul A. Beare
- Rocky Mountain Laboratory, National Institute of Health, Hamilton, MT, United States
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Inthawong M, Pinthong N, Thaiprakhong A, Wangrangsimakul T, Sunyakumthorn P, Hill J, Sonthayanon P, Paris DH, Dunachie SJ, Kronsteiner B. A whole blood intracellular cytokine assay optimised for field site studies demonstrates polyfunctionality of CD4+ T cells in acute scrub typhus. PLoS Negl Trop Dis 2023; 17:e0010905. [PMID: 36961865 PMCID: PMC10075457 DOI: 10.1371/journal.pntd.0010905] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 04/05/2023] [Accepted: 02/25/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND Assessment of cellular immune responses by combining intracellular cytokine staining and immunophenotyping using flow cytometry enables the simultaneous measurement of T cell phenotype and effector function in response to pathogens and vaccines. The use of whole blood samples rather than peripheral blood mononuclear cells avoids both the need for immediate processing and loss of functional antigen presenting cells due to processing and cryopreservation. Using whole blood provides the possibility to stimulate peripheral T cells in situ, and is more suitable for studies where sample volume is limited, such as those involving children, the elderly and critically ill patients. The aim of this study was to provide a robust tool for the assessment of antigen-specific T cell responses in a field site setting with limited resources. METHODOLOGY/PRINCIPLE FINDINGS We optimised a flow cytometry-based whole blood intracellular cytokine assay (WBA) with respect to duration of antigen stimulation and intracellular protein retention time. We demonstrate the ability of the WBA to capture polyfunctional T cell responses in the context of acute scrub typhus infection, by measuring IFN-γ, TNF and IL-2 in CD4+ and CD8+ T cells in response to the causative agent O. tsutsugamushi (OT). Using an optimised OT antigen preparation, we demonstrate the presence of polyfunctional antigen-specific memory CD4+ T cells in the blood of scrub typhus patients. CONCLUSIONS/SIGNIFICANCE In conclusion, this flow cytometry-based WBA is well-suited for use at field study sites, and enables the assessment of polyfunctional T cell responses to infectious agents and vaccines through delineation of antigen-specific cytokine secretion at the single cell level.
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Affiliation(s)
- Manutsanun Inthawong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
| | - Nattapon Pinthong
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Areerat Thaiprakhong
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Tri Wangrangsimakul
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- NDM Center for Global Health Research, Nuffield Dept. of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Piyanate Sunyakumthorn
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok, Thailand
| | - Jennifer Hill
- NDM Center for Global Health Research, Nuffield Dept. of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Piengchan Sonthayanon
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Daniel H. Paris
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Medicine, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Susanna J. Dunachie
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- NDM Center for Global Health Research, Nuffield Dept. of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Barbara Kronsteiner
- Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- NDM Center for Global Health Research, Nuffield Dept. of Clinical Medicine, University of Oxford, Oxford, United Kingdom
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Orientia tsutsugamushi OtDUB Is Expressed and Interacts with Adaptor Protein Complexes during Infection. Infect Immun 2022; 90:e0046922. [PMID: 36374099 PMCID: PMC9753657 DOI: 10.1128/iai.00469-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Orientia tsutsugamushi is an etiologic agent of scrub typhus, a globally emerging rickettsiosis that can be fatal. The bacterium's obligate intracellular lifestyle requires its interaction with host eukaryotic cellular pathways. The proteins it employs to do so and their functions during infection are understudied. Recombinant versions of the recently characterized O. tsutsugamushi deubiquitylase (OtDUB) exhibit high-affinity ubiquitin binding, mediate guanine nucleotide exchange to activate Rho GTPases, bind clathrin adaptor protein complexes 1 and 2, and bind the phospholipid phosphatidylserine. Whether OtDUB is expressed and its function during O. tsutsugamushi infection have yet to be explored. Here, OtDUB expression, location, and interactome during infection were examined. O. tsutsugamushi transcriptionally and translationally expresses OtDUB throughout infection of epithelial, monocytic, and endothelial cells. Results from structured illumination microscopy, surface trypsinization of intact bacteria, and acetic acid extraction of non-integral membrane proteins indicate that OtDUB peripherally associates with the O. tsutsugamushi cell wall and is at least partially present on the bacterial surface. Analyses of the proteins with which OtDUB associates during infection revealed several known O. tsutsugamushi cell wall proteins and others. It also forms an interactome with adapter protein complex 2 and other endosomal membrane traffic regulators. This study documents the first interactors of OtDUB during O. tsutsugamushi infection and establishes a strong link between OtDUB and the host endocytic pathway.
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9
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Marro FC, Laurent F, Josse J, Blocker AJ. Methods to monitor bacterial growth and replicative rates at the single-cell level. FEMS Microbiol Rev 2022; 46:6623663. [PMID: 35772001 PMCID: PMC9629498 DOI: 10.1093/femsre/fuac030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 06/01/2022] [Accepted: 06/28/2022] [Indexed: 01/09/2023] Open
Abstract
The heterogeneity of bacterial growth and replicative rates within a population was proposed a century ago notably to explain the presence of bacterial persisters. The term "growth rate" at the single-cell level corresponds to the increase in size or mass of an individual bacterium while the "replicative rate" refers to its division capacity within a defined temporality. After a decades long hiatus, recent technical innovative approaches allow population growth and replicative rates heterogeneity monitoring at the single-cell level resuming in earnest. Among these techniques, the oldest and widely used is time-lapse microscopy, most recently combined with microfluidics. We also discuss recent fluorescence dilution methods informing only on replicative rates and best suited. Some new elegant single cell methods so far only sporadically used such as buoyant mass measurement and stable isotope probing have emerged. Overall, such tools are widely used to investigate and compare the growth and replicative rates of bacteria displaying drug-persistent behaviors to that of bacteria growing in specific ecological niches or collected from patients. In this review, we describe the current methods available, discussing both the type of queries these have been used to answer and the specific strengths and limitations of each method.
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Affiliation(s)
- Florian C Marro
- Evotec ID Lyon, In Vitro Biology, Infectious Diseases and Antibacterials Unit, Gerland, 69007 Lyon, France,CIRI – Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007 Lyon, France
| | - Frédéric Laurent
- CIRI – Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007 Lyon, France,Institut des Sciences Pharmaceutiques et Biologiques (ISPB), Université Claude Bernard Lyon 1, Lyon, France,Centre de Référence pour la prise en charge des Infections ostéo-articulaires complexes (CRIOAc Lyon; www.crioac-lyon.fr), Hospices Civils de Lyon, Lyon, France,Laboratoire de bactériologie, Institut des Agents Infectieux, French National Reference Center for Staphylococci, Hospices Civils de Lyon, Lyon, France
| | - Jérôme Josse
- CIRI – Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007 Lyon, France,Institut des Sciences Pharmaceutiques et Biologiques (ISPB), Université Claude Bernard Lyon 1, Lyon, France,Centre de Référence pour la prise en charge des Infections ostéo-articulaires complexes (CRIOAc Lyon; www.crioac-lyon.fr), Hospices Civils de Lyon, Lyon, France
| | - Ariel J Blocker
- Corresponding author. Evotec ID Lyon, In Vitro Biology, Infectious Diseases and Antibacterials Unit, France. E-mail:
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10
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Atwal S, Wongsantichon J, Giengkam S, Saharat K, Pittayasathornthun YJ, Chuenklin S, Wang LC, Chung T, Huh H, Lee SH, Sobota RM, Salje J. The obligate intracellular bacterium Orientia tsutsugamushi differentiates into a developmentally distinct extracellular state. Nat Commun 2022; 13:3603. [PMID: 35739103 PMCID: PMC9226355 DOI: 10.1038/s41467-022-31176-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/03/2022] [Indexed: 11/13/2022] Open
Abstract
Orientia tsutsugamushi (Ot) is an obligate intracellular bacterium in the family Rickettsiaceae that causes scrub typhus, a severe mite-borne human disease. Its mechanism of cell exit is unusual amongst Rickettsiaceae, as Ot buds off the surface of infected cells enveloped in plasma membrane. Here, we show that Ot bacteria that have budded out of host cells are in a distinct developmental stage compared with intracellular bacteria. We refer to these two stages as intracellular and extracellular bacteria (IB and EB, respectively). These two forms differ in physical properties: IB is both round and elongated, and EB is round. Additionally, IB has higher levels of peptidoglycan and is physically robust compared with EB. The two bacterial forms differentially express proteins involved in bacterial physiology and host-pathogen interactions, specifically those involved in bacterial dormancy and stress response, and outer membrane autotransporter proteins ScaA and ScaC. Whilst both populations are infectious, entry of IB Ot is sensitive to inhibitors of both clathrin-mediated endocytosis and macropinocytosis, whereas entry of EB Ot is only sensitive to a macropinocytosis inhibitor. Our identification and detailed characterization of two developmental forms of Ot significantly advances our understanding of the intracellular lifecycle of an important human pathogen. Orientia tsutsugamushi (Ot) the causing agent of scrub typhus exits infected cells using a unique mechanism that involves budding off the surface of infected cells. Here, Atwal et al. report that Ots that have budded from their host cells are in a distinct developmental stage than intracellular bacteria and provide the first characterization of this extracellular stage. Both forms are infectious but differ in their physical properties, proteome, and entry mechanism into host cells.
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Affiliation(s)
- Sharanjeet Atwal
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA
| | - Jantana Wongsantichon
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Suparat Giengkam
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kittirat Saharat
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA
| | | | - Suthida Chuenklin
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Loo Chien Wang
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,SingMass-National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Taerin Chung
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA
| | - Hyun Huh
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA
| | - Sang-Hyuk Lee
- Institute for Quantitative Biomedicine, Rutgers University, Piscataway, NJ, USA.,Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Radoslaw M Sobota
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.,SingMass-National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jeanne Salje
- Public Health Research Institute, Rutgers the State University of New Jersey, Newark, NJ, USA. .,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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11
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Sharma D, Sharma A, Singh B, Kumar S, Verma S. Neglected scrub typhus: An updated review with a focus on omics technologies. ASIAN PAC J TROP MED 2022. [DOI: 10.4103/1995-7645.364003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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12
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Hunt JR, Carlyon JA. Analysis of Orientia tsutsugamushi promoter activity. Pathog Dis 2021; 79:6369350. [PMID: 34515306 DOI: 10.1093/femspd/ftab044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/10/2021] [Indexed: 02/07/2023] Open
Abstract
Orientia tsutsugamushi is an obligate intracellular bacterium that causes scrub typhus, a potentially fatal rickettsiosis, and for which no genetic tools exist. Critical to addressing this technical gap is to identify promoters for driving expression of antibiotic resistance and fluorescence reporter genes in O. tsutsugamushi. Such promoters would need to be highly conserved among strains, expressed throughout infection, and exhibit strong activity. We examined the untranslated regions upstream of O. tsutsugamushi genes encoding outer membrane protein A (ompA), 22-kDa type-specific antigen (tsa22) and tsa56. The bacterium transcribed all three during infection of monocytic, endothelial and epithelial cells. Examination of the upstream noncoding regions revealed putative ribosome binding sites, one set of predicted -10 and -35 sequences for ompA and two sets of -10 and -35 sequences for tsa22 and tsa56. Comparison of these regions among geographically diverse O. tsutsugamushi patient isolates revealed nucleotide identities ranging from 84.8 to 100.0%. Upon examination of the candidates for the ability to drive green fluorescence protein expression in Escherichia coli, varying activities were observed with one of the tsa22 promoters being the strongest. Identification and validation of O. tsutsugamushi promoters is an initial key step toward genetically manipulating this important pathogen.
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Affiliation(s)
- Jason R Hunt
- Department of Microbiology and Immunology, Virginia Commonwealth University (VCU) Medical Center, School of Medicine, VCU, Richmond, VA 23298, USA
| | - Jason A Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University (VCU) Medical Center, School of Medicine, VCU, Richmond, VA 23298, USA
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13
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Orientia tsutsugamushi Nucleomodulin Ank13 Exploits the RaDAR Nuclear Import Pathway To Modulate Host Cell Transcription. mBio 2021; 12:e0181621. [PMID: 34340535 PMCID: PMC8406279 DOI: 10.1128/mbio.01816-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Orientia tsutsugamushi is the etiologic agent of scrub typhus, the deadliest of all diseases caused by obligate intracellular bacteria. Nucleomodulins, bacterial effectors that dysregulate eukaryotic transcription, are being increasingly recognized as key virulence factors. How they translocate into the nucleus and their functionally essential domains are poorly defined. We demonstrate that Ank13, an O. tsutsugamushi effector conserved among clinical isolates and expressed during infection, localizes to the nucleus in an importin β1-independent manner. Rather, Ank13 nucleotropism requires an isoleucine at the thirteenth position of its fourth ankyrin repeat, consistent with utilization of eukaryotic RaDAR (RanGDP-ankyrin repeats) nuclear import. RNA-seq analyses of cells expressing green fluorescent protein (GFP)-tagged Ank13, nucleotropism-deficient Ank13I127R, or Ank13ΔF-box, which lacks the F-box domain essential for interacting with SCF ubiquitin ligase, revealed Ank13 to be a nucleomodulin that predominantly downregulates transcription of more than 2,000 genes. Its ability to do so involves its nucleotropism and F-box in synergistic and mutually exclusive manners. Ank13 also acts in the cytoplasm to dysregulate smaller cohorts of genes. The effector’s toxicity in yeast heavily depends on its F-box and less so on its nucleotropism. Genes negatively regulated by Ank13 include those involved in the inflammatory response, transcriptional control, and epigenetics. Importantly, the majority of genes that GFP-Ank13 most strongly downregulates are quiescent or repressed in O. tsutsugamushi-infected cells when Ank13 expression is strongest. Ank13 is the first nucleomodulin identified to coopt RaDAR and a multifaceted effector that functions in the nucleus and cytoplasm via F-box-dependent and -independent mechanisms to globally reprogram host cell transcription.
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14
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Orientia tsutsugamushi selectively stimulates the C-type lectin receptor Mincle and type 1-skewed proinflammatory immune responses. PLoS Pathog 2021; 17:e1009782. [PMID: 34320039 PMCID: PMC8351992 DOI: 10.1371/journal.ppat.1009782] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 08/09/2021] [Accepted: 07/03/2021] [Indexed: 12/20/2022] Open
Abstract
Orientia tsutsugamushi is an obligately intracellular bacterium and the etiological agent of scrub typhus. The lung is a major target organ of infection, displaying type 1-skewed proinflammatory responses. Lung injury and acute respiratory distress syndrome are common complications of severe scrub typhus; yet, their underlying mechanisms remain unclear. In this study, we investigated whether the C-type lectin receptor (CLR) Mincle contributes to immune recognition and dysregulation. Following lethal infection in mice, we performed pulmonary differential expression analysis with NanoString. Of 671 genes examined, we found 312 significantly expressed genes at the terminal phase of disease. Mincle (Clec4e) was among the top 5 greatest up-regulated genes, accompanied with its signaling partners, type 1-skewing chemokines (Cxcr3, Ccr5, and their ligands), as well as Il27. To validate the role of Mincle in scrub typhus, we exposed murine bone marrow-derived macrophages (MΦ) to live or inactivated O. tsutsugamushi and analyzed a panel of CLRs and proinflammatory markers via qRT-PCR. We found that while heat-killed bacteria stimulated transitory Mincle expression, live bacteria generated a robust response in MΦ, which was validated by indirect immunofluorescence and western blot. Notably, infection had limited impact on other tested CLRs or TLRs. Sustained proinflammatory gene expression in MΦ (Cxcl9, Ccl2, Ccl5, Nos2, Il27) was induced by live, but not inactivated, bacteria; infected Mincle-/- MΦ significantly reduced proinflammatory responses compared with WT cells. Together, this study provides the first evidence for a selective expression of Mincle in sensing O. tsutsugamushi and suggests a potential role of Mincle- and IL-27-related pathways in host responses to severe infection. Additionally, it provides novel insight into innate immune recognition of this poorly studied bacterium.
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15
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Discovery of a Diverse Set of Bacteria That Build Their Cell Walls without the Canonical Peptidoglycan Polymerase aPBP. mBio 2021; 12:e0134221. [PMID: 34311584 PMCID: PMC8406291 DOI: 10.1128/mbio.01342-21] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Peptidoglycan (PG) is a highly cross-linked peptide-glycan mesh that confers structural rigidity and shape to most bacterial cells. Polymerization of new PG is usually achieved by the concerted activity of two membrane-bound machineries, class-A penicillin binding proteins (aPBPs) and class-B penicillin binding proteins (bPBPs) in complex with shape, elongation, division, and sporulation (SEDS) proteins. Here, we have identified four phylogenetically distinct groups of bacteria that lack any identifiable aPBPs. We performed experiments on a panel of species within one of these groups, the Rickettsiales, and found that bacteria lacking aPBPs build a PG-like cell wall with minimal abundance and rigidity relative to cell walls of aPBP-containing bacteria. This reduced cell wall may have evolved to minimize the activation of host responses to pathogens and endosymbionts while retaining the minimal PG-biosynthesis machinery required for cell elongation and division. We term these “peptidoglycan-intermediate” bacteria, a cohort of host-associated species that includes some human pathogens.
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16
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Gu XL, Qi R, Li WQ, Jiao YJ, Yu H, Yu XJ. Misdiagnosis of scrub typhus as hemorrhagic fever with renal syndrome and potential co-infection of both diseases in patients in Shandong Province, China, 2013-2014. PLoS Negl Trop Dis 2021; 15:e0009270. [PMID: 33784301 PMCID: PMC8009391 DOI: 10.1371/journal.pntd.0009270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 02/23/2021] [Indexed: 01/27/2023] Open
Abstract
Background Scrub typhus, caused by Orientia tsutsugamushi, an obligate intracellular gram-negative bacterium, along with hemorrhagic fever with renal syndrome (HFRS), caused by hantaviruses, are natural-focus infectious diseases prevalent in Shandong Province, China. Both diseases have similar clinical manifestations in certain disease stages and similar epidemic seasons, which has caused difficulties for physicians in distinguishing them. The aim of this study was to investigate whether misdiagnosis of scrub typhus as HFRS occurred in patients in Shandong Province. Methods Serum samples (N = 112) of clinically suspected HFRS patients from 2013 to 2014 in Shandong Province were analyzed with enzyme-linked immunosorbent assay (ELISA) for antibodies to both hantavirus and Orientia tsutsugamushi. Results ELISA showed that 56.3% (63/112) and 8.0% (9/112) of clinically suspected HFRS patients were IgM antibody positive to hantavirus and O. tsutsugamushi, respectively. Among the hantavirus IgM antibody positive patients, 7.9% (5/63) were also IgM antibody positive to O. tsutsugamushi. Among the hantavirus IgM antibody negative sera, 8.2% (4/49) of sera were positive to O. tsutsugamushi. Conclusions We concluded that some scrub typhus patients were misdiagnosed as HFRS and co-infection of scrub typhus and HFRS might exist in China. Due to the different treatments for scrub typhus and HFRS, physicians should carefully differentiate between scrub typhus and HFRS and consider administering anti-rickettsia antibiotics if treatment for HFRS alone does not work. Scrub typhus is caused by O. tsutsugamushi and hemorrhagic fever with renal syndrome (HFRS) is caused by hantavirus. Both diseases have similar manifestations and have their peak epidemic season in the fall, which makes their clinical differentiation difficult to be differentiated from each other clinically. In this study, we found that scrub typhus was indeed misdiagnosed as HFRS and co-infection of O. tsutsugamushi and hantaviruses might exist in China. Owing to different treatments of HFRS and scrub typhus, physicians need pay attention to differentiate them; identify co-infection of HFRS and scrub typhus; and consider administering antibiotics if antiviral treatment alone does not work.
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Affiliation(s)
- Xiao-lan Gu
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, China
| | - Rui Qi
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, China
| | - Wen-qian Li
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, China
| | - Yong-jun Jiao
- Institute of Pathogenic Microbiology, Jiangsu Provincial Center for Disease Prevention and Control, Key Laboratory of Enteric Pathogenic Microbiology, Ministry Health, Nanjing, China
| | - Hao Yu
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, China
| | - Xue-jie Yu
- State Key Laboratory of Virology, School of Health Sciences, Wuhan University, Wuhan, China
- * E-mail:
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17
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Elliott I, Thangnimitchok N, de Cesare M, Linsuwanon P, Paris DH, Day NPJ, Newton PN, Bowden R, Batty EM. Targeted capture and sequencing of Orientia tsutsugamushi genomes from chiggers and humans. INFECTION GENETICS AND EVOLUTION 2021; 91:104818. [PMID: 33771726 PMCID: PMC8164161 DOI: 10.1016/j.meegid.2021.104818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 03/18/2021] [Accepted: 03/22/2021] [Indexed: 12/12/2022]
Abstract
Scrub typhus is a febrile disease caused by Orientia tsutsugamushi, transmitted by larval stage Trombiculid mites (chiggers), whose primary hosts are small mammals. The phylogenomics of O. tsutsugamushi in chiggers, small mammals and humans remains poorly understood. To combat the limitations imposed by the low relative quantities of pathogen DNA in typical O. tsutsugamushi clinical and ecological samples, along with the technical, safety and cost limitations of cell culture, a novel probe-based target enrichment sequencing protocol was developed. The method was designed to capture variation among conserved genes and facilitate phylogenomic analysis at the scale of population samples. A whole-genome amplification step was incorporated to enhance the efficiency of sequencing by reducing duplication rates. This resulted in on-target capture rates of up to 93% for a diverse set of human, chigger, and rodent samples, with the greatest success rate in samples with real-time PCR Ct values below 35. Analysis of the best-performing samples revealed phylogeographic clustering at local, provincial and international scales. Applying the methodology to a comprehensive set of samples could yield a more complete understanding of the ecology, genomic evolution and population structure of O. tsutsugamushi and other similarly challenging organisms, with potential benefits in the development of diagnostic tests and vaccines.
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Affiliation(s)
- Ivo Elliott
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
| | - Neeranuch Thangnimitchok
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | | | - Piyada Linsuwanon
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Daniel H Paris
- Department of Medicine, Swiss Tropical and Public Health Institute, Basel, Switzerland; Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Nicholas P J Day
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom; Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom; Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rory Bowden
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom; Division of Advanced Technology and Biology, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Elizabeth M Batty
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom; Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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18
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Campos Muzquiz LG, Martínez Gómez D, Reyes Cruz T, Méndez Olvera ET. Evaluation of intracellular survival of Campylobacter fetus subsp. fetus in bovine endometrial cells by qPCR. IRANIAN JOURNAL OF VETERINARY RESEARCH 2021; 22:94-99. [PMID: 34306105 PMCID: PMC8294819 DOI: 10.22099/ijvr.2021.38693.5632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 02/02/2021] [Accepted: 02/28/2021] [Indexed: 09/30/2022]
Abstract
BACKGROUND Campylobacter fetus subsp. fetus is the causal agent of sporadic abortion and infertility in bovines that produces economic losses in livestock. AIMS This study evaluates the capability of C. fetus subsp. fetus to invade and survive in bovine endometrial epithelial cells and attempts to describe a pathogenic mechanism of this microorganism. METHODS Primary culture of bovine endometrial epithelial cells was challenged with C. fetus subsp. fetus. Intracellular bacteria, represented by the number of genomic copies (g.c.) were quantified at 0, 2, 4, 10, and 24 hours post-infection (h.p.i.), by quantitative polymerase chain reaction (qPCR). The presence of intracellular bacteria was evaluated by immunofluorescence and immunohistochemistry. RESULTS The results showed that only viable C. fetus subsp. fetus could invade endometrial cells. The g.c. number in assays with viable C. fetus subsp. fetus reached an average value of 656 g.c., remained constant until 4 h.p.i., then decreased to 100 g.c, at 24 h.p.i. In assays with non-viable microorganisms, the average value of g.c. was less than 1 g.c. and never changed. The intracellular presence of this bacteria was confirmed at 2 h.p.i. by immunofluorescence and immunohistochemistry. CONCLUSION The results suggest that only C. fetus subsp. fetus viable can invade bovine endometrial epithelial cells but will not replicate in them, indicating that the endometrial cells do not represent a replication niche for this pathogen. Nonetheless, this invasion capability suggests that this type of cell could be employed by the pathogen to spread to other tissues.
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Affiliation(s)
- L. G. Campos Muzquiz
- Department of Genetics and Virology, Faculty of Chemical Sciences, Autonomous University of Coahuila, Saltillo, Mexico
| | - D. Martínez Gómez
- Laboratory of Agricultural Microbiology, Department of Agricultural and Animal Production, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico
| | - T. Reyes Cruz
- Biological and Health Sciences Division, Department of Agricultural and Animal Production, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico
| | - E. T. Méndez Olvera
- Laboratory of Molecular Biology, Department of Agricultural and Animal Production, Metropolitan Autonomous University-Xochimilco, Mexico City, Mexico
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19
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Dual RNA-seq of Orientia tsutsugamushi informs on host-pathogen interactions for this neglected intracellular human pathogen. Nat Commun 2020; 11:3363. [PMID: 32620750 PMCID: PMC7335160 DOI: 10.1038/s41467-020-17094-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 06/11/2020] [Indexed: 12/12/2022] Open
Abstract
Studying emerging or neglected pathogens is often challenging due to insufficient information and absence of genetic tools. Dual RNA-seq provides insights into host-pathogen interactions, and is particularly informative for intracellular organisms. Here we apply dual RNA-seq to Orientia tsutsugamushi (Ot), an obligate intracellular bacterium that causes the vector-borne human disease scrub typhus. Half the Ot genome is composed of repetitive DNA, and there is minimal collinearity in gene order between strains. Integrating RNA-seq, comparative genomics, proteomics, and machine learning to study the transcriptional architecture of Ot, we find evidence for wide-spread post-transcriptional antisense regulation. Comparing the host response to two clinical isolates, we identify distinct immune response networks for each strain, leading to predictions of relative virulence that are validated in a mouse infection model. Thus, dual RNA-seq can provide insight into the biology and host-pathogen interactions of a poorly characterized and genetically intractable organism such as Ot.
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20
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Phuklia W, Panyanivong P, Sengdetka D, Sonthayanon P, Newton PN, Paris DH, Day NPJ, Dittrich S. Novel high-throughput screening method using quantitative PCR to determine the antimicrobial susceptibility of Orientia tsutsugamushi clinical isolates. J Antimicrob Chemother 2020; 74:74-81. [PMID: 30295746 PMCID: PMC6293087 DOI: 10.1093/jac/dky402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/05/2018] [Indexed: 01/08/2023] Open
Abstract
Objectives To develop a method to enable the large-scale antimicrobial susceptibility screening of Orientia tsutsugamushi clinical isolates, using one timepoint and one concentration of antibiotics to considerably speed up the time to result. Methods Growth, harvesting, multiplicity of infection (moi) and the day to determine the MICs were optimized using five O. tsutsugamushi reference strains [susceptible (Karp, Kato and Gilliam) and putatively resistant (AFC-3 and AFSC-4)], one clinical isolate (UT76) and one rodent isolate (TA763). Subsequently, the MICs of azithromycin, chloramphenicol and doxycycline for these strains and 51 clinical isolates including AFSC-7 were determined. An optimal concentration was calculated using the epidemiological cut-off value. Results The conditions for O. tsutsugamushi infection, growth and harvesting were determined to be an moi of 100:1 and trypsinization with the peak growth on day 10. The resulting MICs were in line with previously published susceptibility data for all reference strains, except for Karp and AFSC-4, which showed azithromycin MICs of 0.0156 and 0.0313 mg/L, compared with 0.0078 and 0.0156 mg/L, respectively, in previous reports. The MIC of doxycycline for AFC-3 was 0.125 mg/L compared with >4 mg/L in earlier reports. The final single screening concentrations were identified as: azithromycin, 0.125 mg/L; chloramphenicol, 8 mg/L; and doxycycline, 1 mg/L. Conclusions This simplified procedure facilitates the simultaneous screening of 48 isolates for actively monitoring potential resistance of this important fever pathogen, with an 8-fold throughput improvement over early methods. The data do not support the existence of doxycycline- and chloramphenicol-resistant scrub typhus.
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Affiliation(s)
- Weerawat Phuklia
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Phonepasith Panyanivong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Davanh Sengdetka
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Piengchan Sonthayanon
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Daniel H Paris
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sabine Dittrich
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,FIND, Malaria & Fever Program, Geneva, Switzerland
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21
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Atwal S, Giengkam S, Jaiyen Y, Feaga HA, Dworkin J, Salje J. Clickable methionine as a universal probe for labelling intracellular bacteria. J Microbiol Methods 2019; 169:105812. [PMID: 31862457 PMCID: PMC6996152 DOI: 10.1016/j.mimet.2019.105812] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/12/2019] [Accepted: 12/12/2019] [Indexed: 12/13/2022]
Abstract
Despite their clinical and biological importance, the cell biology of obligate intracellular bacteria is less well understood than that of many free-living model organisms. One reason for this is that they are mostly genetically intractable. As a consequence, it is not possible to engineer strains expressing fluorescent proteins and therefore fluorescence light microscopy - a key tool in host-pathogen cell biology studies - is difficult. Strain diversity also limits the universality of antibody-based immunofluorescence approaches. Here, we have developed a universal labelling protocol for intracellular bacteria based on a clickable methionine analog. Whilst we have applied this to obligate intracellular bacteria, we expect it to be useful for labelling free living bacteria as well as other intracellular pathogens.
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Affiliation(s)
- Sharanjeet Atwal
- Public Health Research Institute, Rutgers University of New Jersey, USA
| | | | - Yanin Jaiyen
- Mahidol Oxford Tropical Research Unit, Bangkok, Thailand
| | - Heather A Feaga
- Department of Microbiology & Immunology, College of Physicians and Surgeons, Columbia University, USA
| | - Jonathan Dworkin
- Department of Microbiology & Immunology, College of Physicians and Surgeons, Columbia University, USA
| | - Jeanne Salje
- Public Health Research Institute, Rutgers University of New Jersey, USA; Mahidol Oxford Tropical Research Unit, Bangkok, Thailand; University of Oxford, UK.
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22
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Soong L. Dysregulated Th1 Immune and Vascular Responses in Scrub Typhus Pathogenesis. THE JOURNAL OF IMMUNOLOGY 2019; 200:1233-1240. [PMID: 29431689 DOI: 10.4049/jimmunol.1701219] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/30/2017] [Indexed: 12/25/2022]
Abstract
Scrub typhus is an emerging, insect-transmitted disease caused by Orientia tsutsugamushi, a Gram- and LPS-negative bacterium that replicates freely within professional phagocytes and endothelial cells. Scrub typhus is prevalent with high mortality rates, but information regarding its molecular pathogenesis, microbial virulence determinants, and key immune responses is limited. Improved animal models have recently been developed that respectively resemble the pathological features of self-limiting or severe scrub typhus in humans. Strong activation of Th1 and CD8, but not Th2 and regulatory T, immune responses, accompanied by altered angiopoietin/Tie2-related regulation, are hallmarks of lethal infection in murine models. This review, based primarily on recent advances from clinical and experimental studies, highlights tissue- and endothelial cell-specific biomarkers that are indicative of immune dysregulation. The potential roles of neutrophils and damage-associated molecular pattern molecules at late stages of disease are discussed in the context of vascular leakage, pulmonary and renal injury, and scrub typhus pathogenesis.
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Affiliation(s)
- Lynn Soong
- Department of Microbiology and Immunology, Center for Tropical Diseases, Center for Biodefense and Emerging Infectious Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555; and .,Department of Pathology, Center for Tropical Diseases, Center for Biodefense and Emerging Infectious Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555
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23
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The Obligate Intracellular Bacterium Orientia tsutsugamushi Targets NLRC5 To Modulate the Major Histocompatibility Complex Class I Pathway. Infect Immun 2019; 87:IAI.00876-18. [PMID: 30559222 DOI: 10.1128/iai.00876-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 12/11/2018] [Indexed: 02/06/2023] Open
Abstract
Orientia tsutsugamushi is an obligate intracellular bacterium that infects mononuclear and endothelial cells to cause the emerging global health threat scrub typhus. The ability of O. tsutsugamushi to survive in monocytes facilitates bacterial dissemination to endothelial cells, which can subsequently lead to several potentially fatal sequelae. As a strict intracellular pathogen that lives in the cytoplasm of host cells, O. tsutsugamushi has evolved to counter adaptive immunity. How the pathogen does so and the outcome of this strategy in monocytes versus endothelial cells are poorly understood. This report demonstrates that O. tsutsugamushi reduces cellular levels of NOD-, LRR-, and CARD-containing 5 (NLRC5), a recently identified specific transactivator of major histocompatibility complex class I (MHC-I) component gene expression, to inhibit MHC-I biosynthesis. Importantly, the efficacy of this approach varies with the host cell type infected. In nonprofessional antigen-presenting HeLa and primary human aortic endothelial cells, the O. tsutsugamushi-mediated reduction of NLRC5 results in lowered MHC-I component transcription and, consequently, lower total and/or surface MHC-I levels throughout 72 h of infection. However, in infected THP-1 monocytes, which are professional antigen-presenting cells, the reductions in NLRC5 and MHC-I observed during the first 24 h reverse thereafter. O. tsutsugamushi is the first example of a microbe that targets NLRC5 to modulate the MHC-I pathway. The differential ability of O. tsutsugamushi to modulate this pathway in nonprofessional versus professional antigen-presenting cells could influence morbidity and mortality from scrub typhus.
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24
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Batty EM, Chaemchuen S, Blacksell S, Richards AL, Paris D, Bowden R, Chan C, Lachumanan R, Day N, Donnelly P, Chen S, Salje J. Long-read whole genome sequencing and comparative analysis of six strains of the human pathogen Orientia tsutsugamushi. PLoS Negl Trop Dis 2018; 12:e0006566. [PMID: 29874223 PMCID: PMC6005640 DOI: 10.1371/journal.pntd.0006566] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/18/2018] [Accepted: 05/28/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Orientia tsutsugamushi is a clinically important but neglected obligate intracellular bacterial pathogen of the Rickettsiaceae family that causes the potentially life-threatening human disease scrub typhus. In contrast to the genome reduction seen in many obligate intracellular bacteria, early genetic studies of Orientia have revealed one of the most repetitive bacterial genomes sequenced to date. The dramatic expansion of mobile elements has hampered efforts to generate complete genome sequences using short read sequencing methodologies, and consequently there have been few studies of the comparative genomics of this neglected species. RESULTS We report new high-quality genomes of O. tsutsugamushi, generated using PacBio single molecule long read sequencing, for six strains: Karp, Kato, Gilliam, TA686, UT76 and UT176. In comparative genomics analyses of these strains together with existing reference genomes from Ikeda and Boryong strains, we identify a relatively small core genome of 657 genes, grouped into core gene islands and separated by repeat regions, and use the core genes to infer the first whole-genome phylogeny of Orientia. CONCLUSIONS Complete assemblies of multiple Orientia genomes verify initial suggestions that these are remarkable organisms. They have larger genomes compared with most other Rickettsiaceae, with widespread amplification of repeat elements and massive chromosomal rearrangements between strains. At the gene level, Orientia has a relatively small set of universally conserved genes, similar to other obligate intracellular bacteria, and the relative expansion in genome size can be accounted for by gene duplication and repeat amplification. Our study demonstrates the utility of long read sequencing to investigate complex bacterial genomes and characterise genomic variation.
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Affiliation(s)
- Elizabeth M Batty
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Suwittra Chaemchuen
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Stuart Blacksell
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Allen L Richards
- US Naval Medicine Research Center, Silver Spring, Maryland, United States of America
| | - Daniel Paris
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Medicine, University Basel, Basel, Switzerland
| | - Rory Bowden
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Caroline Chan
- Pacific Biosciences, 1305 O'Brien Drive, Menlo Park, California, United States of America
| | - Ramkumar Lachumanan
- Pacific Biosciences, 1305 O'Brien Drive, Menlo Park, California, United States of America
| | - Nicholas Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Peter Donnelly
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Swaine Chen
- Department of Medicine, Division of Infectious Diseases, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Genome Institute of Singapore, A*STAR, Singapore
| | - Jeanne Salje
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Public Health Research Institute, Rutgers Biomedical and Health Science, Newark, New Jersey, United States of America
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25
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Evans SM, Rodino KG, Adcox HE, Carlyon JA. Orientia tsutsugamushi uses two Ank effectors to modulate NF-κB p65 nuclear transport and inhibit NF-κB transcriptional activation. PLoS Pathog 2018; 14:e1007023. [PMID: 29734393 PMCID: PMC5957444 DOI: 10.1371/journal.ppat.1007023] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/17/2018] [Accepted: 04/11/2018] [Indexed: 01/05/2023] Open
Abstract
Orientia tsutsugamushi causes scrub typhus, a potentially fatal infection that threatens over one billion people. Nuclear translocation of the transcription factor, NF-κB, is the central initiating cellular event in the antimicrobial response. Here, we report that NF-κB p65 nuclear accumulation and NF-κB-dependent transcription are inhibited in O. tsutsugamushi infected HeLa cells and/or primary macrophages, even in the presence of TNFα. The bacterium modulates p65 subcellular localization by neither degrading it nor inhibiting IκBα degradation. Rather, it exploits host exportin 1 to mediate p65 nuclear export, as this phenomenon is leptomycin B-sensitive. O. tsutsugamushi antagonizes NF-κB-activated transcription even when exportin 1 is inhibited and NF-κB consequently remains in the nucleus. Two ankyrin repeat-containing effectors (Anks), Ank1 and Ank6, each of which possess a C-terminal F-box and exhibit 58.5% amino acid identity, are linked to the pathogen's ability to modulate NF-κB. When ectopically expressed, both translocate to the nucleus, abrogate NF-κB-activated transcription in an exportin 1-independent manner, and pronouncedly reduce TNFα-induced p65 nuclear levels by exportin 1-dependent means. Flag-tagged Ank 1 and Ank6 co-immunoprecipitate p65 and exportin 1. Both also bind importin β1, a host protein that is essential for the classical nuclear import pathway. Importazole, which blocks importin β1 activity, abrogates Ank1 and Ank6 nuclear translocation. The Ank1 and Ank6 regions that bind importin β1 also mediate their transport into the nucleus. Yet, these regions are distinct from those that bind p65/exportin 1. The Ank1 and Ank6 F-box and the region that lies between it and the ankyrin repeat domain are essential for blocking p65 nuclear accumulation. These data reveal a novel mechanism by which O. tsutsugamushi modulates the activity and nuclear transport of NF-κB p65 and identify the first microbial proteins that co-opt both importin β1 and exportin 1 to antagonize a critical arm of the antimicrobial response.
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Affiliation(s)
- Sean M. Evans
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Kyle G. Rodino
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Haley E. Adcox
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Jason A. Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
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26
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Orientia tsutsugamushi Modulates Endoplasmic Reticulum-Associated Degradation To Benefit Its Growth. Infect Immun 2017; 86:IAI.00596-17. [PMID: 29109174 DOI: 10.1128/iai.00596-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 10/26/2017] [Indexed: 01/11/2023] Open
Abstract
Orientia tsutsugamushi, an obligate intracellular bacterium that is auxotrophic for the aromatic amino acids and histidine, causes scrub typhus, a potentially deadly infection that threatens 1 billion people. O. tsutsugamushi growth is minimal during the first 24 to 48 h of infection but its growth becomes logarithmic thereafter. How the pathogen modulates cellular functions to support its growth is poorly understood. The unfolded protein response (UPR) is a cytoprotective pathway that relieves endoplasmic reticulum (ER) stress by promoting ER-associated degradation (ERAD) of misfolded proteins. Here, we show that O. tsutsugamushi invokes the UPR in the first 48 h and benefits from ER stress in an amino acid-dependent manner. O. tsutsugamushi also impedes ERAD during this time period. By 72 h, ER stress is alleviated and ERAD proceeds unhindered. Sustained inhibition of ERAD using RNA interference results in an O. tsutsugamushi growth defect at 72 h that can be rescued by amino acid supplementation. Thus, O. tsutsugamushi temporally stalls ERAD until ERAD-derived amino acids are needed to support its growth. The O. tsutsugamushi effector Ank4 is linked to this phenomenon. Ank4 interacts with Bat3, a eukaryotic chaperone that is essential for ERAD, and is transiently expressed by O. tsutsugamushi during the infection period when it inhibits ERAD. Ectopically expressed Ank4 blocks ERAD to phenocopy O. tsutsugamushi infection. Our data reveal a novel mechanism by which an obligate intracellular bacterial pathogen modulates ERAD to satisfy its nutritional virulence requirements.
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27
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Xu G, Walker DH, Jupiter D, Melby PC, Arcari CM. A review of the global epidemiology of scrub typhus. PLoS Negl Trop Dis 2017; 11:e0006062. [PMID: 29099844 PMCID: PMC5687757 DOI: 10.1371/journal.pntd.0006062] [Citation(s) in RCA: 274] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 11/15/2017] [Accepted: 10/21/2017] [Indexed: 12/18/2022] Open
Abstract
Scrub typhus is a serious public health problem in the Asia-Pacific area. It threatens one billion people globally, and causes illness in one million people each year. Caused by Orientia tsutsugamushi, scrub typhus can result in severe multiorgan failure with a case fatality rate up to 70% without appropriate treatment. The antigenic heterogeneity of O. tsutsugamushi precludes generic immunity and allows reinfection. As a neglected disease, there is still a large gap in our knowledge of the disease, as evidenced by the sporadic epidemiologic data and other related public health information regarding scrub typhus in its endemic areas. Our objective is to provide a systematic analysis of current epidemiology, prevention and control of scrub typhus in its long-standing endemic areas and recently recognized foci of infection.
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Affiliation(s)
- Guang Xu
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - David H. Walker
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Daniel Jupiter
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Peter C. Melby
- Department of Internal Medicine, Division of Infectious Diseases, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Christine M. Arcari
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, Texas, United States of America
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28
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Atwal S, Giengkam S, Chaemchuen S, Dorling J, Kosaisawe N, VanNieuwenhze M, Sampattavanich S, Schumann P, Salje J. Evidence for a peptidoglycan-like structure in Orientia tsutsugamushi. Mol Microbiol 2017; 105:440-452. [PMID: 28513097 PMCID: PMC5523937 DOI: 10.1111/mmi.13709] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2017] [Indexed: 01/04/2023]
Abstract
Bacterial cell walls are composed of the large cross-linked macromolecule peptidoglycan, which maintains cell shape and is responsible for resisting osmotic stresses. This is a highly conserved structure and the target of numerous antibiotics. Obligate intracellular bacteria are an unusual group of organisms that have evolved to replicate exclusively within the cytoplasm or vacuole of a eukaryotic cell. They tend to have reduced amounts of peptidoglycan, likely due to the fact that their growth and division takes place within an osmotically protected environment, and also due to a drive to reduce activation of the host immune response. Of the two major groups of obligate intracellular bacteria, the cell wall has been much more extensively studied in the Chlamydiales than the Rickettsiales. Here, we present the first detailed analysis of the cell envelope of an important but neglected member of the Rickettsiales, Orientia tsutsugamushi. This bacterium was previously reported to completely lack peptidoglycan, but here we present evidence supporting the existence of a peptidoglycan-like structure in Orientia, as well as an outer membrane containing a network of cross-linked proteins, which together confer cell envelope stability. We find striking similarities to the unrelated Chlamydiales, suggesting convergent adaptation to an obligate intracellular lifestyle.
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Affiliation(s)
- Sharanjeet Atwal
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok Thailand
| | - Suparat Giengkam
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok Thailand
| | - Suwittra Chaemchuen
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok Thailand
| | - Jack Dorling
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Nont Kosaisawe
- Siriraj Laboratory for Systems Pharmacology, Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand
| | | | - Somponnat Sampattavanich
- Siriraj Laboratory for Systems Pharmacology, Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand
| | - Peter Schumann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Jeanne Salje
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok Thailand
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29
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Abstract
The obligate intracellular bacterium Orientia tsutsugamushi is responsible for more than one million cases of scrub typhus annually throughout the Asia-Pacific region. Human infection occurs via the bite of the larval form (chigger) of several species of trombiculid mites. While in some patients the result of infection is a mild, febrile illness, others experience severe complications, which may even be fatal. This review discusses the genome and biology of the causative agent, the changing epidemiology of scrub typhus, the challenges of its diagnosis, and current treatment recommendations.
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Affiliation(s)
- Sunil Thomas
- Lankenau Institute for Medical Research, Wynnewood, Pennsylvania USA
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30
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Atwal S, Giengkam S, VanNieuwenhze M, Salje J. Live imaging of the genetically intractable obligate intracellular bacteria Orientia tsutsugamushi using a panel of fluorescent dyes. J Microbiol Methods 2016; 130:169-176. [PMID: 27582280 PMCID: PMC5073074 DOI: 10.1016/j.mimet.2016.08.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 08/23/2016] [Accepted: 08/23/2016] [Indexed: 12/20/2022]
Abstract
Our understanding of the molecular mechanisms of bacterial infection and pathogenesis are disproportionally derived from a small number of well-characterised species and strains. One reason for this is the enormous time and resources required to develop a new organism into experimental system that can be interrogated at the molecular level, in particular with regards to the development of genetic tools. Live cell imaging by fluorescence microscopy is a powerful technique to study biological processes such as bacterial motility, host cell invasion, and bacterial growth and division. In the absence of genetic tools that enable exogenous expression of fluorescent proteins, fluorescent chemical probes can be used to label and track living cells. A large number of fluorescent chemical probes are commercially available, but these have overwhelmingly been applied to the study of eukaryotic cell systems. Here, we present a methodical analysis of four different classes of probes, which can be used to delineate the cytoplasm, nucleic acids, cell membrane or peptidoglycan of living bacterial cells. We have tested these in the context of the important but neglected human pathogen Orientia tsutsugamushi but expect that the methodology would be broadly applicable to other bacterial species. A panel of fluorescent dyes are used to label living cells of the obligate intracellular bacterium Orientia tsutsugamushi. These dyes include CFSE, SYTO9, DiI/DiO/DiD and HADA. These dyes label the bacterial cytoplasm, nucleic acids, lipid membrane and cell wall respectively.
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Affiliation(s)
- Sharanjeet Atwal
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Suparat Giengkam
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Jeanne Salje
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
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