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Fromm L, Mehl J, Keller C. Orientia tsutsugamushi: A life between escapes. Microbiologyopen 2023; 12:e1380. [PMID: 37877457 PMCID: PMC10493369 DOI: 10.1002/mbo3.1380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 08/31/2023] [Indexed: 10/26/2023] Open
Abstract
The life cycle of the mite-borne, obligate intracellular pathogen Orientia tsutsugamushi (Ot), the causative agent of human scrub typhus, differs in many aspects from that of other members of the Rickettsiales order. Particularly, the nonlytic cellular exit of individual Ot bacteria at the plasma membrane closely resembles the budding of enveloped viruses but has only been rudimentarily studied at the molecular level. This brief article is focused on the current state of knowledge of escape events in the life cycle of Ot and highlights differences in strategies of other rickettsiae.
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Affiliation(s)
- Lea Fromm
- Institute of VirologyPhilipps University MarburgMarburgGermany
| | - Jonas Mehl
- Institute of VirologyPhilipps University MarburgMarburgGermany
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Panda S, Swain SK, Sahu BP, Sarangi R. Gene expression and involvement of signaling pathways during host-pathogen interplay in Orientia tsutsugamushi infection. 3 Biotech 2022; 12:180. [PMID: 35860421 PMCID: PMC9295102 DOI: 10.1007/s13205-022-03239-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/18/2022] [Indexed: 11/22/2022] Open
Abstract
Scrub typhus is a neglected tropical disease that affects one-third of the world’s population. The disease is caused by Orientia tsutsugamushi (OT), an obligate intracellular Gram-negative bacterium. OT efficiently escapes from the endosomal pathway after entering the host cell and replicates inside cytosol. OT infection promotes cellular autophagy, the autonomous defense mechanism unlike other bacteria. This study has discussed the bacterial invasion process through the extracellular matrix and the immune response activated by the bacterium within the hosts. Furthermore, we have emphasized the importance of extracellular matrix and their cross-talk with the immune cells, such as, macrophages, neutrophils, and dendritic cells followed by their inflammatory response. We have also put an insight into the host factors associated with signaling pathways during scrub typhus disease with a special focus on the OT-induced stress response, autophagy, apoptosis, and innate immunity. Multiple cytokines and chemokines play a significant role in activating different immune-related signaling pathways. Due to the presence of high antigenic diversity among strains, the signaling pathways during the host–pathogen interplay of OT with its host is very complicated. Thus, it hinders to mitigate the severity of the pandemic occurred by the respective pathogen. Our investigation will provide a useful guide to better understand the virulence and physiology of this intracellular pathogen which will lead towards a better therapeutic diagnosis and vaccine development.
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Affiliation(s)
- Subhasmita Panda
- Department of Pediatrics, IMS and SUM Hospital, Siksha 'O' Anusandhan Deemed to be University, K8, Kalinga Nagar, Bhubaneswar, Odisha 751003 India
| | - Subrat Kumar Swain
- Centre for Genomics and Biomedical Informatics, IMS and SUM Hospital, Siksha 'O' Anusandhan Deemed to be University, K8, Kalinga Nagar, Bhubaneswar, Odisha 751003 India
| | - Basanta Pravas Sahu
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552 India
| | - Rachita Sarangi
- Department of Pediatrics, IMS and SUM Hospital, Siksha 'O' Anusandhan Deemed to be University, K8, Kalinga Nagar, Bhubaneswar, Odisha 751003 India
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Abstract
Several monosaccharides constitute naturally occurring glycans, but it is uncertain whether they constitute a universal set like the alphabets of proteins and DNA. Based on the available experimental observations, it is hypothesized herein that the glycan alphabet is not universal. Data on the presence/absence of pathways for the biosynthesis of 55 monosaccharides in 12 939 completely sequenced archaeal and bacterial genomes are presented in support of this hypothesis. Pathways were identified by searching for homologues of biosynthesis pathway enzymes. Substantial variations were observed in the set of monosaccharides used by organisms belonging to the same phylum, genera and even species. Monosaccharides were grouped as common, less common and rare based on their prevalence in Archaea and Bacteria. It was observed that fewer enzymes are sufficient to biosynthesize monosaccharides in the common group. It appears that the common group originated before the formation of the three domains of life. In contrast, the rare group is confined to a few species in a few phyla, suggesting that these monosaccharides evolved much later. Fold conservation, as observed in aminotransferases and SDR (short-chain dehydrogenase reductase) superfamily members involved in monosaccharide biosynthesis, suggests neo- and sub-functionalization of genes led to the formation of the rare group monosaccharides. The non-universality of the glycan alphabet begets questions about the role of different monosaccharides in determining an organism’s fitness.
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Affiliation(s)
- Jaya Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - P Sunthar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Petety V Balaji
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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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: 11] [Impact Index Per Article: 3.7] [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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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: 20] [Impact Index Per Article: 6.7] [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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Banerjee A, Kulkarni S. Orientia tsutsugamushi: The dangerous yet neglected foe from the East. Int J Med Microbiol 2020; 311:151467. [PMID: 33338890 DOI: 10.1016/j.ijmm.2020.151467] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 10/06/2020] [Accepted: 11/25/2020] [Indexed: 01/22/2023] Open
Abstract
Orientia tsutsugamushi (OT), the causative agent of the vector-borne Scrub typhus zoonotic disease in humans, is a unique microorganism that exists in the Asia-Pacific region since a long time. In spite of its occurrence, the organism had been neglected until recent years. Humans are the accidental dead-end hosts of O. tsutsugamushi and display manifestations which are both severe and misleading. The vast antigenic diversity of OT and non-pathognomic symptoms of Scrub typhus, create hurdles in the clinical management of the disease and impede the OT-research. Many countries in the Asia-Pacific region have reported the resurgence of OT- infections and have raised concerns for its expanding distribution. This has triggered the development of advanced techniques for diagnosis and research on exploring a successful vaccine candidate to reduce the burden of the disease. Thus, the aim of this systematic review is to provide an update on the recent advances in the OT-research and highlight the key areas that have remained obscure and demand attention.
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Affiliation(s)
- Anwesha Banerjee
- ICMR-National AIDS Research Institute, Bhosari, Pune, 411026, India
| | - Smita Kulkarni
- ICMR-National AIDS Research Institute, Bhosari, Pune, 411026, India.
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Torina A, Villari S, Blanda V, Vullo S, La Manna MP, Shekarkar Azgomi M, Di Liberto D, de la Fuente J, Sireci G. Innate Immune Response to Tick-Borne Pathogens: Cellular and Molecular Mechanisms Induced in the Hosts. Int J Mol Sci 2020; 21:ijms21155437. [PMID: 32751625 PMCID: PMC7432002 DOI: 10.3390/ijms21155437] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/11/2022] Open
Abstract
Many pathogens are transmitted by tick bites, including Anaplasma spp., Ehrlichia spp., Rickettsia spp., Babesia and Theileria sensu stricto species. These pathogens cause infectious diseases both in animals and humans. Different types of immune effector mechanisms could be induced in hosts by these microorganisms, triggered either directly by pathogen-derived antigens or indirectly by molecules released by host cells binding to these antigens. The components of innate immunity, such as natural killer cells, complement proteins, macrophages, dendritic cells and tumor necrosis factor alpha, cause a rapid and intense protection for the acute phase of infectious diseases. Moreover, the onset of a pro-inflammatory state occurs upon the activation of the inflammasome, a protein scaffold with a key-role in host defense mechanism, regulating the action of caspase-1 and the maturation of interleukin-1β and IL-18 into bioactive molecules. During the infection caused by different microbial agents, very similar profiles of the human innate immune response are observed including secretion of IL-1α, IL-8, and IFN-α, and suppression of superoxide dismutase, IL-1Ra and IL-17A release. Innate immunity is activated immediately after the infection and inflammasome-mediated changes in the pro-inflammatory cytokines at systemic and intracellular levels can be detected as early as on days 2–5 after tick bite. The ongoing research field of “inflammasome biology” focuses on the interactions among molecules and cells of innate immune response that could be responsible for triggering a protective adaptive immunity. The knowledge of the innate immunity mechanisms, as well as the new targets of investigation arising by bioinformatics analysis, could lead to the development of new methods of emergency diagnosis and prevention of tick-borne infections.
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Affiliation(s)
- Alessandra Torina
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (A.T.); (S.V.); (S.V.)
| | - Sara Villari
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (A.T.); (S.V.); (S.V.)
| | - Valeria Blanda
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (A.T.); (S.V.); (S.V.)
- Correspondence:
| | - Stefano Vullo
- Istituto Zooprofilattico Sperimentale della Sicilia, Via Gino Marinuzzi 3, 90100 Palermo, Italy; (A.T.); (S.V.); (S.V.)
| | - Marco Pio La Manna
- Central Laboratory of Advanced Diagnostic and Biological Research (CLADIBIOR), BIND, University Hospital “Paolo Giaccone”, Università degli studi di Palermo, Via del Vespro 129, 90100 Palermo, Italy; (M.P.L.M.); (M.S.A.); (D.D.L.); (G.S.)
| | - Mojtaba Shekarkar Azgomi
- Central Laboratory of Advanced Diagnostic and Biological Research (CLADIBIOR), BIND, University Hospital “Paolo Giaccone”, Università degli studi di Palermo, Via del Vespro 129, 90100 Palermo, Italy; (M.P.L.M.); (M.S.A.); (D.D.L.); (G.S.)
| | - Diana Di Liberto
- Central Laboratory of Advanced Diagnostic and Biological Research (CLADIBIOR), BIND, University Hospital “Paolo Giaccone”, Università degli studi di Palermo, Via del Vespro 129, 90100 Palermo, Italy; (M.P.L.M.); (M.S.A.); (D.D.L.); (G.S.)
| | - José de la Fuente
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ronda de Toledo s/n, 13005 Ciudad Real, Spain;
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Guido Sireci
- Central Laboratory of Advanced Diagnostic and Biological Research (CLADIBIOR), BIND, University Hospital “Paolo Giaccone”, Università degli studi di Palermo, Via del Vespro 129, 90100 Palermo, Italy; (M.P.L.M.); (M.S.A.); (D.D.L.); (G.S.)
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Allen PE, Martinez JJ. Modulation of Host Lipid Pathways by Pathogenic Intracellular Bacteria. Pathogens 2020; 9:pathogens9080614. [PMID: 32731350 PMCID: PMC7460438 DOI: 10.3390/pathogens9080614] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/17/2020] [Accepted: 07/25/2020] [Indexed: 12/22/2022] Open
Abstract
Lipids are a broad group of molecules required for cell maintenance and homeostasis. Various intracellular pathogens have developed mechanisms of modulating and sequestering host lipid processes for a large array of functions for both bacterial and host cell survival. Among the host cell lipid functions that intracellular bacteria exploit for infection are the modulation of host plasma membrane microdomains (lipid rafts) required for efficient bacterial entry; the recruitment of specific lipids for membrane integrity of intracellular vacuoles; and the utilization of host lipid droplets for the regulation of immune responses and for energy production through fatty acid β-oxidation and oxidative phosphorylation. The majority of published studies on the utilization of these host lipid pathways during infection have focused on intracellular bacterial pathogens that reside within a vacuole during infection and, thus, have vastly different requirements for host lipid metabolites when compared to those intracellular pathogens that are released into the host cytosol upon infection. Here we summarize the mechanisms by which intracellular bacteria sequester host lipid species and compare the modulation of host lipid pathways and metabolites during host cell infection by intracellular pathogens residing in either a vacuole or within the cytosol of infected mammalian cells. This review will also highlight common and unique host pathways necessary for intracellular bacterial growth that could potentially be targeted for therapeutic intervention.
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Tantibhedhyangkul W, Wongsawat E, Matamnan S, Inthasin N, Sueasuay J, Suputtamongkol Y. Anti-Mycoplasma Activity of Daptomycin and Its Use for Mycoplasma Elimination in Cell Cultures of Rickettsiae. Antibiotics (Basel) 2019; 8:antibiotics8030123. [PMID: 31438510 PMCID: PMC6784056 DOI: 10.3390/antibiotics8030123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/15/2019] [Accepted: 08/17/2019] [Indexed: 12/24/2022] Open
Abstract
Mycoplasma contamination detrimentally affects cellular functions and the growth of intracellular pathogens in cell cultures. Although several mycoplasmacidal agents are commercially available for sterile cell cultures, they are not applicable to rickettsia-infected cells. In our attempt to find an anti-mycoplasma drug for contaminated rickettsial cultures, we determined the susceptibilities of three common Mycoplasma species to daptomycin. Mycoplasma orale and M. arginini showed low-level resistance to daptomycin (minimum inhibitory concentration, MIC = 2 mg/L), whereas M. hyorhinis was high-level resistant (MIC = 32 mg/L). However, some Mycoplasma isolates developed higher resistance to daptomycin after failed treatments with inadequate doses or durations. An aminoglycoside (gentamicin) was still active against M. hyorhinis and could be used in Orientia cultures. For complete eradication of mycoplasmas in Rickettsia cultures, we recommend a 3-week treatment with daptomycin at 256 mg/L. In contaminated Orientia cultures, daptomycin at 32 mg/L was effective in eradicating M. orale, whereas either gentamicin or amikacin (100 mg/L) was effective in eradicating M. hyorhinis. Unlike each drug alone, the combinations of daptomycin plus clindamycin and/or quinupristin/dalfopristin proved effective in eradicating M. hyorhinis. In summary, our study demonstrated the in vitro anti-mycoplasma activity of daptomycin and its application as a new mycoplasma decontamination method for Rickettsia and Orientia cultures.
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Affiliation(s)
- Wiwit Tantibhedhyangkul
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Ekkarat Wongsawat
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Sutthicha Matamnan
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Naharuthai Inthasin
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jintapa Sueasuay
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Yupin Suputtamongkol
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
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Lalchhandama K. Orientia tsutsugamushi, the agent of scrub typhus. WIKIJOURNAL OF MEDICINE 2019. [DOI: 10.15347/wjm/2019.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Serological Cross-Reactivity among Orientia tsutsugamushi Serotypes but Not with Rickettsia japonica in Japan. Trop Med Infect Dis 2018; 3:tropicalmed3030074. [PMID: 30274470 PMCID: PMC6161089 DOI: 10.3390/tropicalmed3030074] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 06/30/2018] [Accepted: 07/03/2018] [Indexed: 11/25/2022] Open
Abstract
The rickettsial diseases Japanese spotted fever (JSF) and scrub typhus (ST) are caused by Rickettsia japonica and Orientia tsutsugamushi, respectively. The diseases share clinical symptoms, such as fever, rash, and eschar. However, there are no systematical investigations of the serological cross-reactivity between R. japonica and O. tsutsugamushi. Also, the serological cross-reactivity among O. tsutsugamushi serotypes is still unclear. We analyzed 1406 cases tested by indirect immunoperoxidase assay using seven rickettsial antigens—one R. japonica and six O. tsutsugamushi serotypes—between 2003 and 2016 at two reference centers in Japan. Of these, 167 JSF and 190 ST cases were serologically diagnosed. None of the ST cases had a significant increase in IgM titers against R. japonica. Six JSF cases showed IgG titers of ≥40 against O. tsutsugamushi, but no IgG titer showed a significant elevation in the convalescent phase sample. We observed a substantial degree of cross-reactivity between O. tsutsugamushi serotypes. Cross-reactivity was significant among Karp, Hirano/Kuroki, and Kato types and between Gilliam and Irie/Kawasaki types in IgM, while the Shimokoshi type was less cross-reactive than the others. In conclusion, there is no serological cross-reaction between R. japonica and O. tsutsugamushi. The cross-reactivity among O.tsutsugamushi varies depending on serotypes.
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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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Díaz FE, Abarca K, Kalergis AM. An Update on Host-Pathogen Interplay and Modulation of Immune Responses during Orientia tsutsugamushi Infection. Clin Microbiol Rev 2018; 31:e00076-17. [PMID: 29386235 PMCID: PMC5967693 DOI: 10.1128/cmr.00076-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The obligate intracellular bacterium Orientia tsutsugamushi is the causative agent of scrub typhus in humans, a serious mite-borne disease present in a widespread area of endemicity, which affects an estimated 1 million people every year. This disease may exhibit a broad range of presentations, ranging from asymptomatic to fatal conditions, with the latter being due to disseminated endothelial infection and organ injury. Unique characteristics of the biology and host-pathogen interactions of O. tsutsugamushi, including the high antigenic diversity among strains and the highly variable, short-lived memory responses developed by the host, underlie difficulties faced in the pursuit of an effective vaccine, which is an imperative need. Other factors that have hindered scientific progress relative to the infectious mechanisms of and the immune response triggered by this bacterium in vertebrate hosts include the limited number of mechanistic studies performed on animal models and the lack of genetic tools currently available for this pathogen. However, recent advances in animal model development are promising to improve our understanding of host-pathogen interactions. Here, we comprehensively discuss the recent advances in and future perspectives on host-pathogen interactions and the modulation of immune responses related to this reemerging disease, highlighting the role of animal models.
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Affiliation(s)
- Fabián E Díaz
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Katia Abarca
- Departamento en Enfermedades Infecciosas e Inmunología Pediátricas, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Koralur M, Singh R, Varma M, Shenoy S, Acharya V, Kamath A, Stenos J, Athan E, Bairy I. Scrub typhus diagnosis on acute specimens using serological and molecular assays - a 3-year prospective study. Diagn Microbiol Infect Dis 2018; 91:112-117. [PMID: 29706479 DOI: 10.1016/j.diagmicrobio.2018.01.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 01/18/2018] [Accepted: 01/23/2018] [Indexed: 01/19/2023]
Abstract
Scrub typhus (ST) is an underdiagnosed acute febrile illness in the Asia Pacific region with recent reemergence. Clinical diagnosis is difficult, and laboratory confirmation is largely based on serological and molecular tests. However, Weil-Felix test still remains the only test available in much of the rural tropics where a disproportionate number of cases occur. Sensitive and affordable assays are important for broader use and accurate diagnosis. We evaluated the diagnostic capabilities of serological and molecular assays on single acute clinical samples. Out of 1036 cases, 319 were confirmed as ST, and the sensitivities of immunofluorescent assay (IFA), IgM enzyme-linked immunosorbent assay (ELISA), nested polymerase chain reaction (n-PCR) and WFT were 93.4%, 80.3%, 75.2%, and 54.2%, respectively. IgM ELISA + n-PCR combination demonstrated highest degree of agreement (κ = .911) in the absence of IFA. Additionally, 16 cases were detected by n-PCR only. Our study emphasizes the diagnostic challenges in the developing world, importance of molecular tests, and best alternate assays in ST diagnosis.
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Affiliation(s)
- Munegowda Koralur
- Department of Microbiology, Kasturba Medical College, Manipal Academy of Higher Education (MAHE), Manipal, India.
| | - Rahul Singh
- Kasturba Medical College, Manipal Academy of Higher Education (MAHE), Manipal, India.
| | - Muralidhar Varma
- Department of Medicine, Kasturba Medical College, Manipal Academy of Higher Education (MAHE), Manipal, India.
| | - Shalini Shenoy
- Department of Microbiology, Kasturba Medical College, Mangaluru, Manipal Academy of Higher Education (MAHE), India.
| | - Vasudeva Acharya
- Department of Medicine, Kasturba Medical College, Manipal Academy of Higher Education (MAHE), Manipal, India.
| | - Asha Kamath
- Department of Community Medicine, Kasturba Medical College, Manipal Academy of Higher Education (MAHE), Manipal, India.
| | - John Stenos
- Australian Rickettsial Reference Laboratory, Geelong, VIC, Australia.
| | - Eugen Athan
- Department of Infectious Diseases, Barwon Health, Australia.
| | - Indira Bairy
- Department of Microbiology, Melaka Manipal Medical College, Manipal Campus, Manipal Academy of Higher Education (MAHE), Manipal, India.
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15
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Otten C, Brilli M, Vollmer W, Viollier PH, Salje J. Peptidoglycan in obligate intracellular bacteria. Mol Microbiol 2018; 107:142-163. [PMID: 29178391 PMCID: PMC5814848 DOI: 10.1111/mmi.13880] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2017] [Indexed: 01/08/2023]
Abstract
Peptidoglycan is the predominant stress-bearing structure in the cell envelope of most bacteria, and also a potent stimulator of the eukaryotic immune system. Obligate intracellular bacteria replicate exclusively within the interior of living cells, an osmotically protected niche. Under these conditions peptidoglycan is not necessarily needed to maintain the integrity of the bacterial cell. Moreover, the presence of peptidoglycan puts bacteria at risk of detection and destruction by host peptidoglycan recognition factors and downstream effectors. This has resulted in a selective pressure and opportunity to reduce the levels of peptidoglycan. In this review we have analysed the occurrence of genes involved in peptidoglycan metabolism across the major obligate intracellular bacterial species. From this comparative analysis, we have identified a group of predicted 'peptidoglycan-intermediate' organisms that includes the Chlamydiae, Orientia tsutsugamushi, Wolbachia and Anaplasma marginale. This grouping is likely to reflect biological differences in their infection cycle compared with peptidoglycan-negative obligate intracellular bacteria such as Ehrlichia and Anaplasma phagocytophilum, as well as obligate intracellular bacteria with classical peptidoglycan such as Coxiella, Buchnera and members of the Rickettsia genus. The signature gene set of the peptidoglycan-intermediate group reveals insights into minimal enzymatic requirements for building a peptidoglycan-like sacculus and/or division septum.
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Affiliation(s)
- Christian Otten
- The Centre for Bacterial Cell BiologyInstitute for Cell and Molecular Biosciences, Newcastle UniversityNewcastle upon TyneNE2 4AXUK
| | - Matteo Brilli
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE)University of Padova. Agripolis ‐ V.le dell'Università, 16 | 35020 Legnaro PadovaItaly
- Present address:
Department of BiosciencesUniversity of Milan, via Celoria 26(MI)Italy
| | - Waldemar Vollmer
- The Centre for Bacterial Cell BiologyInstitute for Cell and Molecular Biosciences, Newcastle UniversityNewcastle upon TyneNE2 4AXUK
| | - Patrick H. Viollier
- Department of Microbiology and Molecular MedicineInstitute of Genetics & Genomics in Geneva (iGE3), University of GenevaGenevaSwitzerland
| | - Jeanne Salje
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global HealthUniversity of OxfordOxfordUK
- Mahidol‐Oxford Tropical Medicine Research UnitMahidol UniversityBangkokThailand
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16
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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: 22] [Impact Index Per Article: 3.1] [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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17
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Toll-Like Receptor 2 Recognizes Orientia tsutsugamushi and Increases Susceptibility to Murine Experimental Scrub Typhus. Infect Immun 2016; 84:3379-3387. [PMID: 27620720 DOI: 10.1128/iai.00185-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 09/06/2016] [Indexed: 12/17/2022] Open
Abstract
Scrub typhus is a potentially lethal infection that is caused by the obligate intracellular bacterium Orientia tsutsugamushi The roles of Toll-like receptor 2 (TLR2) and TLR4 in innate recognition of O. tsutsugamushi have not been elucidated. By overexpression of TLR2 or TLR4 in HEK293 cells, we demonstrated that TLR2, but not TLR4, recognizes heat-stable compounds of O. tsutsugamushi that were sensitive to treatment with sodium hydroxide, hydrogen peroxide, and proteinase K. TLR2 was required for the secretion of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) by dendritic cells. In an intradermal mouse infection model, TLR2-deficient mice did not show impaired control of bacterial growth or reduced survival. Moreover, after intraperitoneal infection, TLR2-deficient mice were even more resistant to lethal infection than C57BL/6 wild-type mice, which showed stronger symptoms and lower survival rates during the convalescent phase. Compared to the time of reduction of bacterial loads in TLR2-deficient mice, the reduction of bacterial loads in infected organs was accelerated in wild-type mice. The higher mortality of wild-type mice was associated with increased concentrations of serum alkaline phosphatase but not aspartate aminotransferase. The transcription of mRNA for TNF-α and IL-6 decreased more rapidly in peritoneum samples from wild-type mice than in those from TLR2-deficient mice and was therefore not a correlate of increased susceptibility. Thus, although TLR2 is an important mediator of the early inflammatory response, it is dispensable for protective immunity against O. tsutsugamushi Increased susceptibility to O. tsutsugamushi infection in TLR2-competent mice rather suggests a TLR2-related immunopathologic effect.
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18
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Deviant Behavior: Tick-Borne Pathogens and Inflammasome Signaling. Vet Sci 2016; 3:vetsci3040027. [PMID: 29056735 PMCID: PMC5606592 DOI: 10.3390/vetsci3040027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/22/2016] [Accepted: 09/23/2016] [Indexed: 12/11/2022] Open
Abstract
In the face of an assault, host cells mount an immediate response orchestrated by innate immunity. Two of the best described innate immune signaling networks are the Toll- and the Nod-like receptor pathways. Extensive work has been done characterizing both signaling cascades with several recent advances on the forefront of inflammasome biology. In this review, we will discuss how more commonly-studied pathogens differ from tick-transmitted microbes in the context of Nod-like receptor signaling and inflammasome formation. Because pathogens transmitted by ticks have unique characteristics, we offer the opinion that these microbes can be used to uncover novel principles of Nod-like receptor biology.
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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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20
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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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21
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Wang X, Shaw DK, Hammond HL, Sutterwala FS, Rayamajhi M, Shirey KA, Perkins DJ, Bonventre JV, Velayutham TS, Evans SM, Rodino KG, VieBrock L, Scanlon KM, Carbonetti NH, Carlyon JA, Miao EA, McBride JW, Kotsyfakis M, Pedra JHF. The Prostaglandin E2-EP3 Receptor Axis Regulates Anaplasma phagocytophilum-Mediated NLRC4 Inflammasome Activation. PLoS Pathog 2016; 12:e1005803. [PMID: 27482714 PMCID: PMC4970705 DOI: 10.1371/journal.ppat.1005803] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 07/11/2016] [Indexed: 01/21/2023] Open
Abstract
Rickettsial agents are sensed by pattern recognition receptors but lack pathogen-associated molecular patterns commonly observed in facultative intracellular bacteria. Due to these molecular features, the order Rickettsiales can be used to uncover broader principles of bacterial immunity. Here, we used the bacterium Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis, to reveal a novel microbial surveillance system. Mechanistically, we discovered that upon A. phagocytophilum infection, cytosolic phospholipase A2 cleaves arachidonic acid from phospholipids, which is converted to the eicosanoid prostaglandin E2 (PGE2) via cyclooxygenase 2 (COX2) and the membrane associated prostaglandin E synthase-1 (mPGES-1). PGE2-EP3 receptor signaling leads to activation of the NLRC4 inflammasome and secretion of interleukin (IL)-1β and IL-18. Importantly, the receptor-interacting serine/threonine-protein kinase 2 (RIPK2) was identified as a major regulator of the immune response against A. phagocytophilum. Accordingly, mice lacking COX2 were more susceptible to A. phagocytophilum, had a defect in IL-18 secretion and exhibited splenomegaly and damage to the splenic architecture. Remarkably, Salmonella-induced NLRC4 inflammasome activation was not affected by either chemical inhibition or genetic ablation of genes associated with PGE2 biosynthesis and signaling. This divergence in immune circuitry was due to reduced levels of the PGE2-EP3 receptor during Salmonella infection when compared to A. phagocytophilum. Collectively, we reveal the existence of a functionally distinct NLRC4 inflammasome illustrated by the rickettsial agent A. phagocytophilum.
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Affiliation(s)
- Xiaowei Wang
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Dana K. Shaw
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Holly L. Hammond
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Fayyaz S. Sutterwala
- Division of Infectious Diseases, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Manira Rayamajhi
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kari Ann Shirey
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Darren J. Perkins
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Joseph V. Bonventre
- Renal Division, Brigham and Women’s Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Thangam S. Velayutham
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Sean M. Evans
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Kyle G. Rodino
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Lauren VieBrock
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Karen M. Scanlon
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Nicholas H. Carbonetti
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jason A. Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Edward A. Miao
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jere W. McBride
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Michail Kotsyfakis
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Budweis, Czech Republic
| | - Joao H. F. Pedra
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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22
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Shaw DK, Kotsyfakis M, Pedra JHF. For Whom the Bell Tolls (and Nods): Spit-acular Saliva. CURRENT TROPICAL MEDICINE REPORTS 2016; 3:40-50. [PMID: 27547699 DOI: 10.1007/s40475-016-0072-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Having emerged during the early part of the Cretaceous period, ticks are an ancient group of hematophagous ectoparasites with significant veterinary and public health importance worldwide. The success of their life strategy can be attributed, in part, to saliva. As we enter into a scientific era where the collection of massive data sets and structures for biological application is possible, we suggest that understanding the molecular mechanisms that govern the life cycle of ticks is within grasp. With this in mind, we discuss what is currently known regarding the manipulation of Toll-like (TLR) and Nod-like (NLR) receptor signaling pathways by tick salivary proteins, and how these molecules impact pathogen transmission.
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Affiliation(s)
- Dana K Shaw
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
| | - Michail Kotsyfakis
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Budweis, Czech Republic
| | - Joao H F Pedra
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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23
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Weinert LA, Araujo-Jnr EV, Ahmed MZ, Welch JJ. The incidence of bacterial endosymbionts in terrestrial arthropods. Proc Biol Sci 2016; 282:20150249. [PMID: 25904667 DOI: 10.1098/rspb.2015.0249] [Citation(s) in RCA: 283] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Intracellular endosymbiotic bacteria are found in many terrestrial arthropods and have a profound influence on host biology. A basic question about these symbionts is why they infect the hosts that they do, but estimating symbiont incidence (the proportion of potential host species that are actually infected) is complicated by dynamic or low prevalence infections. We develop a maximum-likelihood approach to estimating incidence, and testing hypotheses about its variation. We apply our method to a database of screens for bacterial symbionts, containing more than 3600 distinct arthropod species and more than 150 000 individual arthropods. After accounting for sampling bias, we estimate that 52% (CIs: 48-57) of arthropod species are infected with Wolbachia, 24% (CIs: 20-42) with Rickettsia and 13% (CIs: 13-55) with Cardinium. We then show that these differences stem from the significantly reduced incidence of Rickettsia and Cardinium in most hexapod orders, which might be explained by evolutionary differences in the arthropod immune response. Finally, we test the prediction that symbiont incidence should be higher in speciose host clades. But while some groups do show a trend for more infection in species-rich families, the correlations are generally weak and inconsistent. These results argue against a major role for parasitic symbionts in driving arthropod diversification.
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Affiliation(s)
- Lucy A Weinert
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, UK
| | - Eli V Araujo-Jnr
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, UK
| | - Muhammad Z Ahmed
- University of Florida, Institute of Food and Agricultural Sciences, Tropical Research and Education Center, 18905 SW 280th Street, Homestead, FL 33031, USA
| | - John J Welch
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, UK
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24
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Tsai MH, Chang CH, Tsai RK, Hong YR, Chuang TH, Fan KT, Peng CW, Wu CY, Hsu WL, Wang LS, Chen LK, Yu HS. Cross-Regulation of Proinflammatory Cytokines by Interleukin-10 and miR-155 in Orientia tsutsugamushi-Infected Human Macrophages Prevents Cytokine Storm. J Invest Dermatol 2016; 136:1398-1407. [PMID: 26921773 DOI: 10.1016/j.jid.2015.11.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 10/22/2015] [Accepted: 11/06/2015] [Indexed: 11/28/2022]
Abstract
Scrub typhus is caused by the obligate intracellular bacterium Orientia tsutsugamushi. Macrophages are host cells for its replication and clearance. Severe complications in patients are mainly caused by a cytokine storm resulting from overproduction of proinflammatory cytokines; nevertheless, the molecular mechanism for the occurrence remains obscure. Herein, we investigate the interactive regulation of cytokines and micro-RNA (miR) in human macrophages infected with low and high doses of O. tsutsugamushi. During low dose infection, macrophages produce high levels of IL-10 through extracellular signal-regulated kinase activation, which inhibits proinflammatory cytokine production and facilitates pathogen replication. Increasing levels of pathogen results in reduced levels of IL-10, and macrophages begin to generate high levels of proinflammatory cytokines through NF-κB activation. However, during a high dose infection, macrophages produce high levels of miR-155 to slow the proinflammatory response. The extracellular signal-regulated kinase/IL-10 axis suppresses the NF-κB/tumor necrosis factor alpha axis via activation of signal transducer and activator of transcription 3. Both IL-10 and miR-155 inhibit the NF-κB signaling pathway. Furthermore, IL-10 is a potent inhibitor of miR-155. Patients susceptible to a cytokine storm, peripheral blood mononuclear cells showed significantly lower IL-10 and miR-155 responses to O. tsutsugamushi challenge. Thus, IL-10 and miR-155 operate inhibitory mechanisms to achieve a proper defense mechanism and prevent a cytokine storm.
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Affiliation(s)
- Ming-Hsien Tsai
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chung-Hsing Chang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Dermatology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Research Center for Applied Sciences, Academic Sinica, Taipei, Taiwan.
| | - Rong-Kung Tsai
- Institute of Medical Sciences, School of Medicine, Tzu Chi University, Hualien, Taiwan; Institute of Eye Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.
| | - Yi-Ren Hong
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Tsung-Hsien Chuang
- Immunology Research Center, National Health Research Institutes, Zhunan, Taiwan
| | - Kan-Tang Fan
- Department of Dermatology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Chi-Wen Peng
- Institute of Medical Sciences, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Ching-Ying Wu
- Department of Dermatology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Wen-Li Hsu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Lih-Shinn Wang
- Department of Internal Medicine, Section of Infectious Diseases, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Li-Kuang Chen
- Department of Medical Laboratory, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Hsin-Su Yu
- Research Center for Applied Sciences, Academic Sinica, Taipei, Taiwan; National Environmental Health Research Center, National Health Research Institutes, Zhunan, Taiwan
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25
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Lee SM, Kwon HY, Im JH, Baek JH, Kang JS, Lee JS. Identification of Outer Membrane Vesicles Derived from Orientia tsutsugamushi. J Korean Med Sci 2015; 30:866-70. [PMID: 26130947 PMCID: PMC4479938 DOI: 10.3346/jkms.2015.30.7.866] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 04/01/2015] [Indexed: 11/23/2022] Open
Abstract
Orientia tsutsugamushi, a causative pathogen of Scrub typhus, is a gram-negative intracellular bacterium. Outer membrane vesicles (OMVs) are produced from the membrane of bacteria and play many roles related to the survival of the pathogen. However, there have been no reports confirming whether O. tsutsugamushi indeed produce OMVs. O. tsutsugamushi boryong was cultured in ECV-304 cells for the purification of OMVs. Western blot analysis and immunoenrichment using anti-O. tsutsugamushi monoclonal antibody and electron microscopy were employed for identification and characterization of OMVs. We confirm the presence of OMVs derived from O. tsutsugamushi, and also found that those OMVs contain a major surface antigen of 56-kDa protein and variant immunogenic antigens.
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Affiliation(s)
- Sun-Myoung Lee
- Translation Research Center, Inha University School of Medicine, Incheon, Korea
| | - Hea Yoon Kwon
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Jae-Hyong Im
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Ji Hyeon Baek
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
| | - Jae-Seung Kang
- Department of Microbiology, Inha University School of Medicine, Incheon, Korea
| | - Jin-Soo Lee
- Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea
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26
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Shim SK, Shin YK, Choi EN, Han BG, Lee HK, Choi YS, Lee BC, Yoon KS, Park MY. Analysis of Cellular Fatty Acids inOrientia tsutsugamushias Taxonomic Markers. Microbiol Immunol 2013; 49:343-7. [PMID: 15840959 DOI: 10.1111/j.1348-0421.2005.tb03738.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Six Orientia strains including 3 prototype strains such as Gilliam, Karp, and Kato, and 3 strains (Boryong, Pajoo, and Yongworl) isolated in Korea, were studied for the profiles of their cellular fatty acids. All tested strains contained octadecenoic acid C (18: 1) omega 9 c(57.3 +/- 3.5%), octadecanoic acid C (18: 0) (15.3 +/- 1.5%), and hexadecanoic acid C (16: 0) (12.7 +/- 1.7%) as major components; however, interestingly, eicosenoic acid C (20: 1) omega 9 c(2.6 +/- 0.6%) was found in all strains except the Yongworl strain. Furthermore none of the strains contained 3-hydroxy fatty acids. The ratios of total saturated fatty acid (SFA) to total unsaturated fatty acid (UFA) were within the range of 0.34 to 0.54. These results showed that the cellular fatty acid profile should provide more reliable information for the identification of these bacteria.
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Affiliation(s)
- Soo-Kyoung Shim
- Division of Rickettsial and Zoonotic Diseases, Department of Bacteriology, National Institute of Health, Seoul, Korea
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Valbuena G, Walker DH. Approaches to vaccines against Orientia tsutsugamushi. Front Cell Infect Microbiol 2013; 2:170. [PMID: 23316486 PMCID: PMC3539663 DOI: 10.3389/fcimb.2012.00170] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 12/14/2012] [Indexed: 12/02/2022] Open
Abstract
Scrub typhus is a severe mite-borne infection caused by Orientia tsutsugamushi, an obligately intracellular bacterium closely related to Rickettsia. The disease explains a substantial proportion of acute undifferentiated febrile cases that require hospitalization in rural areas of Asia, the North of Australia, and many islands of the Pacific Ocean. Delayed antibiotic treatment is common due to the lack of effective commercially available diagnostic tests and the lack of specificity of the early clinical presentation. The systemic infection of endothelial cells that line the vasculature with Orientia can lead to many complications and fatalities. In survivors, immunity does not last long, and is poorly cross-reactive among numerous strains. In addition, chronic infections are established in an unknown number of patients. All those characteristics justify the pursuit of a prophylactic vaccine against O. tsutsugamushi; however, despite continuous efforts to develop such a vaccine since World War II, the objective has not been attained. In this review, we discuss the history of vaccine development against Orientia to provide a clear picture of the challenges that we continue to face from the perspective of animal models and the immunological challenges posed by an intracellular bacterium that normally triggers a short-lived immune response. We finish with a proposal for development of an effective and safe vaccine for scrub typhus through a new approach with a strong focus on T cell-mediated immunity, empirical testing of the immunogenicity of proteins encoded by conserved genes, and assessment of protection in relevant animal models that truly mimic human scrub typhus.
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Affiliation(s)
- Gustavo Valbuena
- Department of Pathology, University of Texas Medical Branch Galveston, TX, USA.
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28
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Choi JH, Cheong TC, Ha NY, Ko Y, Cho CH, Jeon JH, So I, Kim IK, Choi MS, Kim IS, Cho NH. Orientia tsutsugamushi subverts dendritic cell functions by escaping from autophagy and impairing their migration. PLoS Negl Trop Dis 2013; 7:e1981. [PMID: 23301113 PMCID: PMC3536799 DOI: 10.1371/journal.pntd.0001981] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 11/05/2012] [Indexed: 11/26/2022] Open
Abstract
Background Dendritic cells (DCs) are the most potent antigen-presenting cells that link innate and adaptive immune responses, playing a pivotal role in triggering antigen-specific immunity. Antigen uptake by DCs induces maturational changes that include increased surface expression of major histocompatibility complex (MHC) and costimulatory molecules. In addition, DCs actively migrate to regional lymph nodes and activate antigen-specific naive T cells after capturing antigens. We characterize the functional changes of DCs infected with Orientia tsutsugamushi, the causative agent of scrub typhus, since there is limited knowledge of the role played by DCs in O. tsutsugamushi infection. Methodology/Principal Finding O. tsutsugamushi efficiently infected bone marrow-derived DCs and induced surface expression of MHC II and costimulatory molecules. In addition, O. tsutsugamushi induced autophagy activation, but actively escaped from this innate defense system. Infected DCs also secreted cytokines and chemokines such as IL-6, IL-12, MCP5, MIP-1α, and RANTES. Furthermore, in vitro migration of DCs in the presence of a CCL19 gradient within a 3D collagen matrix was drastically impaired when infected with O. tsutsugamushi. The infected cells migrated much less efficiently into lymphatic vessels of ear dermis ex vivo when compared to LPS-stimulated DCs. In vivo migration of O. tsutsugamushi-infected DCs to regional lymph nodes was significantly impaired and similar to that of immature DCs. Finally, we found that MAP kinases involved in chemotactic signaling were differentially activated in O. tsutsugamushi-infected DCs. Conclusion/Significance These results suggest that O. tsutsugamushi can target DCs to exploit these sentinel cells as replication reservoirs and delay or impair the functional maturation of DCs during the bacterial infection in mammals. Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi infection and is one of the main causes of febrile illness in the Asia-Pacific region. If not properly treated with antibiotics, patients often develop severe vasculitis that affects multiple organs, and the mortality rate of untreated patients reaches up to 30%. To understand the pathogenic mechanisms of the infectious disease, we characterized the functional changes of O. tsutsugamushi–infected dendritic cells (DCs), which play a pivotal role in orchestrating innate and adaptive immune responses. The obligate intracellular bacteria efficiently infected bone marrow-derived DCs and activated the cells as measured by induced surface expression of MHC II and costimulatory molecules, secretion of cytokines and chemokines, and autophagy induction. However, the live bacteria actively escaped from host autophagosomes and the migration of infected cells was severely impaired in vitro, ex vivo, and in vivo infection models. Finally, we found that MAP kinases involved in chemotactic signaling were differentially activated in O. tsutsugamushi-infected DCs. These results suggest that O. tsutsugamushi can target DCs to exploit these sentinel cells as replication reservoirs and delay or impair the functional maturation of DCs during the bacterial infection in mammals.
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Affiliation(s)
- Ji-Hye Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Taek-Chin Cheong
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Na-Young Ha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Youngho Ko
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Chung-Hyun Cho
- Pharmacology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ju-Hong Jeon
- Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Insuk So
- Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - In-Kyu Kim
- Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Myung-Sik Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ik-Sang Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Jongno-Gu, Seoul, Republic of Korea
- * E-mail:
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29
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Ge Y, Rikihisa Y. Subversion of host cell signaling by Orientia tsutsugamushi. Microbes Infect 2011; 13:638-48. [PMID: 21458586 DOI: 10.1016/j.micinf.2011.03.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 03/13/2011] [Accepted: 03/14/2011] [Indexed: 01/08/2023]
Abstract
Progress has been made in deciphering the mechanisms on Orientia tsutsugamushi-host interaction. The genome sequencing, microarray and proteomic analyses of this ancient bacterium have provided a wealth of new information. This paper reviews the general characteristics of O. tsutsugamushi and recent developments especially in signaling events involved in the bacteria--host interaction.
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Affiliation(s)
- Yan Ge
- Department of Immunology and Pathogen Biology, Tongji University School of Medicine, Shanghai 200092, China.
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30
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Genome-based construction of the metabolic pathways of Orientia tsutsugamushi and comparative analysis within the Rickettsiales order. Comp Funct Genomics 2010:623145. [PMID: 18528528 PMCID: PMC2408715 DOI: 10.1155/2008/623145] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 01/29/2008] [Accepted: 03/04/2008] [Indexed: 11/18/2022] Open
Abstract
Orientia tsutsugamushi, the causative agent of
scrub typhus, is an obligate intracellular
bacterium that belongs to the order of
Rickettsiales. Recently, we have reported that
O. tsutsugamushi has a unique
genomic structure, consisting of highly
repetitive sequences, and suggested that it may
provide valuable insight into the evolution of
intracellular bacteria. Here, we have used
genomic information to construct the major
metabolic pathways of
O. tsutsugamushi and performed a
comparative analysis of the metabolic genes and
pathways of O. tsutsugamushi
with other members of the Rickettsiales order.
While O. tsutsugamushi has the
largest genome among the members of this order,
mainly due to the presence of repeated
sequences, its metabolic pathways have been
highly streamlined. Overall, the metabolic
pathways of O. tsutsugamushi
were similar to Rickettsia but
there were notable differences in several
pathways including carbohydrate metabolism, the
TCA cycle, and the synthesis of cell wall
components as well as in the transport systems.
Our results will provide a useful guide to the
postgenomic analysis of
O. tsutsugamushi and lead
to a better understanding of the virulence and
physiology of this intracellular pathogen.
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31
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Abstract
With an obligate intracellular lifestyle, Alphaproteobacteria of the order Rickettsiales have inextricably coevolved with their various eukaryotic hosts, resulting in small, reductive genomes and strict dependency on host resources. Unsurprisingly, large portions of Rickettsiales genomes encode proteins involved in transport and secretion. One particular transporter that has garnered recent attention from researchers is the type IV secretion system (T4SS). Homologous to the well-studied archetypal vir T4SS of Agrobacterium tumefaciens, the Rickettsiales vir homolog (rvh) T4SS is characterized primarily by duplication of several of its genes and scattered genomic distribution of all components in several conserved islets. Phylogeny estimation suggests a single event of ancestral acquirement of the rvh T4SS, likely from a nonalphaproteobacterial origin. Bioinformatics analysis of over 30 Rickettsiales genome sequences illustrates a conserved core rvh scaffold (lacking only a virB5 homolog), with lineage-specific diversification of several components (rvhB1, rvhB2, and rvhB9b), likely a result of modifications to cell envelope structure. This coevolution of the rvh T4SS and cell envelope morphology is probably driven by adaptations to various host cells, identifying the transporter as an important target for vaccine development. Despite the genetic intractability of Rickettsiales, recent advancements have been made in the characterization of several components of the rvh T4SS, as well as its putative regulators and substrates. While current data favor a role in effector translocation, functions in DNA uptake and release and/or conjugation cannot at present be ruled out, especially considering that a mechanism for plasmid transfer in Rickettsia spp. has yet to be proposed.
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32
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Yun JH, Koo JE, Koh YS. Mitogen-activated protein kinases are involved in tumor necrosis factor alpha production in macrophages infected with Orientia tsutsugamushi. Microbiol Immunol 2009; 53:349-55. [PMID: 19493203 DOI: 10.1111/j.1348-0421.2009.00127.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Orientia tsutsugamushi, an obligatory intracellular bacterium, is the causative agent of scrub typhus. Here the role of MAPK in TNF-alpha production in macrophages after infection with O. tsutsugamushi has been investigated. ERK1/2, JNK, and p38 MAPK became phosphorylated in Orientia-stimulated macrophages. Selective inhibitors of MAPK cascades could all significantly reduce Orientia-stimulated TNF-alpha production. Orientia-stimulated TNF-alpha production via p38 and JNK pathways was regulated by a post-transcriptional mechanism, whereas the ERK pathway mainly controlled the transcriptional step of TNF-alpha gene expression during infection. In conclusion, our data indicate that MAPK signaling is required to induce maximal TNF-alpha production in macrophages during Orientia infection.
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Affiliation(s)
- Ji-Hyun Yun
- Department of Microbiology, School of Medicine, BK21 Program, and Institute of Medical Science, Cheju National University, Jeju 690-756, Republic of Korea
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33
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Nakayama K, Yamashita A, Kurokawa K, Morimoto T, Ogawa M, Fukuhara M, Urakami H, Ohnishi M, Uchiyama I, Ogura Y, Ooka T, Oshima K, Tamura A, Hattori M, Hayashi T. The Whole-genome sequencing of the obligate intracellular bacterium Orientia tsutsugamushi revealed massive gene amplification during reductive genome evolution. DNA Res 2008; 15:185-99. [PMID: 18508905 PMCID: PMC2575882 DOI: 10.1093/dnares/dsn011] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Scrub typhus (‘Tsutsugamushi’ disease in Japanese) is a mite-borne infectious disease. The causative agent is Orientia tsutsugamushi, an obligate intracellular bacterium belonging to the family Rickettsiaceae of the subdivision alpha-Proteobacteria. In this study, we determined the complete genome sequence of O. tsutsugamushi strain Ikeda, which comprises a single chromosome of 2 008 987 bp and contains 1967 protein coding sequences (CDSs). The chromosome is much larger than those of other members of Rickettsiaceae, and 46.7% of the sequence was occupied by repetitive sequences derived from an integrative and conjugative element, 10 types of transposable elements, and seven types of short repeats of unknown origins. The massive amplification and degradation of these elements have generated a huge number of repeated genes (1196 CDSs, categorized into 85 families), many of which are pseudogenes (766 CDSs), and also induced intensive genome shuffling. By comparing the gene content with those of other family members of Rickettsiacea, we identified the core gene set of the family Rickettsiaceae and found that, while much more extensive gene loss has taken place among the housekeeping genes of Orientia than those of Rickettsia, O. tsutsugamushi has acquired a large number of foreign genes. The O. tsutsugamushi genome sequence is thus a prominent example of the high plasticity of bacterial genomes, and provides the genetic basis for a better understanding of the biology of O. tsutsugamushi and the pathogenesis of ‘Tsutsugamushi’ disease.
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Affiliation(s)
- Keisuke Nakayama
- Division of Microbiology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, 5200 Kiyotake, Miyazaki, Japan
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34
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Tseng BY, Yang HH, Liou JH, Chen LK, Hsu YH. Immunohistochemical study of scrub typhus: a report of two cases. Kaohsiung J Med Sci 2008; 24:92-8. [PMID: 18281226 DOI: 10.1016/s1607-551x(08)70103-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Scrub typhus is a zoonotic disease caused by Orientia tsutsugamushi, which is transmitted by chiggers. The target cells of this rickettsia are poorly defined in humans. Immunohistochemical staining of tissue sections of patients with scrub typhus is helpful in investigating the target cells of this rickettsia in different organs. We studied two autopsy specimens by immunohistochemical staining using a specific antibody against O. tsutsugamushi. Rickettsiae were located in endothelial cells in all of the organs evaluated, namely heart, lung, brain, kidney, appendix and skin, within cardiac muscle cells and renal tubular epithelial cells, and in macrophages located in the lymph node, liver and spleen. In conclusion, O. tsutsugamushi may disseminate into multiple organs through endothelial cells and macrophages, resulting in the development of fatal complications.
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Affiliation(s)
- Bo-Yuan Tseng
- Department of Pathology, Buddhist Tzu Chi General Hospital and University, Hualien, Taiwan
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35
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Kim MK, Kim MJ, Lee SM, Kang JS. Identification of the Proteinase K-resistant Antigen of Orientia tsutsugamushi by Monoclonal Antibodies. ACTA ACUST UNITED AC 2008. [DOI: 10.4167/jbv.2008.38.1.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Mee-Kyung Kim
- Department of Microbiology, Center for Advanced Medical Education by BK21 Project, and Research Institute for Medical Scineces, Inha University College of Medicine, Inchon 400-1031, Republic of Korea
| | - Mi-Jeong Kim
- Department of Microbiology, Center for Advanced Medical Education by BK21 Project, and Research Institute for Medical Scineces, Inha University College of Medicine, Inchon 400-1031, Republic of Korea
| | - Sun-Myoung Lee
- Department of Microbiology, Center for Advanced Medical Education by BK21 Project, and Research Institute for Medical Scineces, Inha University College of Medicine, Inchon 400-1031, Republic of Korea
| | - Jae-Seung Kang
- Department of Microbiology, Center for Advanced Medical Education by BK21 Project, and Research Institute for Medical Scineces, Inha University College of Medicine, Inchon 400-1031, Republic of Korea
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36
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Fournier PE, Siritantikorn S, Rolain JM, Suputtamongkol Y, Hoontrakul S, Charoenwat S, Losuwanaluk K, Parola P, Raoult D. Detection of new genotypes of Orientia tsutsugamushi infecting humans in Thailand. Clin Microbiol Infect 2007; 14:168-73. [PMID: 18076670 DOI: 10.1111/j.1469-0691.2007.01889.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PCR screening of blood specimens taken from 195 patients with serologically confirmed scrub typhus in three Thai provinces detected the 56-kDa protein-encoding gene from Orientia tsutsugamushi in ten (5%) patients. Significant genetic diversity was found among the ten amplicons, with nine new genotypes identified that were different from those found previously in Thailand. Phylogenetically, the ten sequences obtained in the present study and sequences from 71 strains characterised previously were distributed into several clusters that included the Karp, Gilliam, Kuroki, Saitama, Kawasaki and Kato clusters. Two of the new genotypes found in the present study clearly belonged to the Karp cluster. However, the other new genotypes formed three different clusters, including one cluster that appeared to be distant from all previously known clusters, and which may therefore be representative of a previously undescribed serotype. Other genotypes formed two other clusters that may also be associated with undescribed serotypes.
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Affiliation(s)
- P-E Fournier
- Unité des Rickettsies, IFR 48, CNRS UMR6020, Faculté de Médecine, Université de la Méditerranée, Marseille, France
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37
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Long X, Deng S, Mattner J, Zang Z, Zhou D, McNary N, Goff RD, Teyton L, Bendelac A, Savage PB. Synthesis and evaluation of stimulatory properties of Sphingomonadaceae glycolipids. Nat Chem Biol 2007; 3:559-64. [PMID: 17660835 DOI: 10.1038/nchembio.2007.19] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Accepted: 06/30/2007] [Indexed: 02/07/2023]
Abstract
Glycosphingolipids (GSLs) from the Sphingomonadaceae family of bacteria have been reported to be potent stimulators of natural killer T cells. These glycolipids include mono-, tri- and tetraglycosylceramides. Here we have prepared the GSL-1 to GSL-4 series of glycolipids and tested their abilities to stimulate natural killer T cells. Among these glycolipids, only GSL-1 (1) is a potent stimulator. Using a series of synthetic diglycosylceramides, we show that oligoglycosylceramides from Sphingomonadaceae are not effectively truncated to GSL-1 in lysosomes in antigen-presenting cells, possibly because the higher-order GSLs are poor substrates for lysosomal acyltransfer enzymes.
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Affiliation(s)
- Xiangtian Long
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, Utah 84602, USA
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38
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Kim MK, Kim MJ, Lim BU, Kang JS. Stabilizing Microtubular Network Facilitates the Intracellular Growth ofOrientia tsutsugamushi. ACTA ACUST UNITED AC 2006. [DOI: 10.4167/jbv.2006.36.2.51] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Mee-Kyung Kim
- Inha Research Institute for Medical Sciences, Incheon 400-712, Republic of Korea
| | - Mi-Jeong Kim
- Department of Microbiology, Inha University College of Medicine, Incheon 400-712, Republic of Korea
| | - Byung-Uk Lim
- Department of Microbiology, Inha University College of Medicine, Incheon 400-712, Republic of Korea
| | - Jae-Seung Kang
- Department of Microbiology, Inha University College of Medicine, Incheon 400-712, Republic of Korea
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39
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Mattner J, Debord KL, Ismail N, Goff RD, Cantu C, Zhou D, Saint-Mezard P, Wang V, Gao Y, Yin N, Hoebe K, Schneewind O, Walker D, Beutler B, Teyton L, Savage PB, Bendelac A. Exogenous and endogenous glycolipid antigens activate NKT cells during microbial infections. Nature 2005; 434:525-9. [PMID: 15791258 DOI: 10.1038/nature03408] [Citation(s) in RCA: 863] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Accepted: 01/24/2005] [Indexed: 12/19/2022]
Abstract
CD1d-restricted natural killer T (NKT) cells are innate-like lymphocytes that express a conserved T-cell receptor and contribute to host defence against various microbial pathogens. However, their target lipid antigens have remained elusive. Here we report evidence for microbial, antigen-specific activation of NKT cells against Gram-negative, lipopolysaccharide (LPS)-negative alpha-Proteobacteria such as Ehrlichia muris and Sphingomonas capsulata. We have identified glycosylceramides from the cell wall of Sphingomonas that serve as direct targets for mouse and human NKT cells, controlling both septic shock reaction and bacterial clearance in infected mice. In contrast, Gram-negative, LPS-positive Salmonella typhimurium activates NKT cells through the recognition of an endogenous lysosomal glycosphingolipid, iGb3, presented by LPS-activated dendritic cells. These findings identify two novel antigenic targets of NKT cells in antimicrobial defence, and show that glycosylceramides are an alternative to LPS for innate recognition of the Gram-negative, LPS-negative bacterial cell wall.
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MESH Headings
- Animals
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/immunology
- Antigens, Bacterial/pharmacology
- Antigens, CD1/genetics
- Antigens, CD1/immunology
- Antigens, CD1d
- Cell Wall/chemistry
- Cell Wall/immunology
- Cells, Cultured
- Ceramides/chemical synthesis
- Ceramides/chemistry
- Ceramides/immunology
- Ceramides/pharmacology
- Dendritic Cells/drug effects
- Dendritic Cells/immunology
- Ehrlichia/immunology
- Ehrlichia/isolation & purification
- Gram-Negative Bacterial Infections/immunology
- Gram-Negative Bacterial Infections/microbiology
- Humans
- Killer Cells, Natural/drug effects
- Killer Cells, Natural/immunology
- Lipopolysaccharides/pharmacology
- Lymphocyte Activation/drug effects
- Lymphocyte Activation/immunology
- Mice
- Salmonella typhimurium/immunology
- Shock, Septic/immunology
- Shock, Septic/microbiology
- Sphingomonas/immunology
- Spleen/immunology
- T-Lymphocyte Subsets/drug effects
- T-Lymphocyte Subsets/immunology
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Affiliation(s)
- Jochen Mattner
- Committee on Immunology, University of Chicago, Chicago, Illinois 60637, USA
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40
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Kim MK, Seong SY, Seoh JY, Han TH, Song HJ, Lee JE, Shin JH, Lim BU, Kang JS. Orientia tsutsugamushi inhibits apoptosis of macrophages by retarding intracellular calcium release. Infect Immun 2002; 70:4692-6. [PMID: 12117985 PMCID: PMC128204 DOI: 10.1128/iai.70.8.4692-4696.2002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Orientia tsutsugamushi shows both pro- and antiapoptotic activities in infected vertebrate cells. Apoptosis of THP-1 cells induced by beauvericin was inhibited by O. tsutsugamushi infection. Beauvericin-induced calcium redistribution was significantly reduced and retarded in cells infected with O. tsutsugamushi. Antiapoptotic activities of O. tsutsugamushi in infected cells are most probably due to inhibition of the increase in the cytosolic calcium concentration.
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Affiliation(s)
- Mee-Kyung Kim
- Department of Microbiology, Inha University College of Medicine, Inchon 400-103, Republic of Korea
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41
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Kim MK, Kang JS. Orientia tsutsugamushi suppresses the production of inflammatory cytokines induced by its own heat-stable component in murine macrophages. Microb Pathog 2001; 31:145-50. [PMID: 11500099 DOI: 10.1006/mpat.2001.0457] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Orientia tsutsugamushi is a Gram-negative obligate intracellular bacterium, which causes scrub typhus. To understand the pathogenesis of scrub typhus, we have investigated the induction of tumor necrosis alpha (TNF-alpha) and interleukin-6 (IL-6) by O. tsutsugamushi in two murine macrophage cell lines. Both live and heat-killed orientia stimulated the production of cytokines in J774A.1 cells. Polymyxin B does not affect the secretion of cytokines. These together with the fact that the immature macrophage cell line, P388D1, did not produce TNF-alpha when induced by either live or heat-killed O. tsutsugamushi strongly argue against any roles of lipopolysaccharide (LPS) in cytokine production. Furthermore, the result that the cytokine responses were more brisk when macrophage cell lines had been induced by heat-killed O. tsutsugamushi than by live organisms strongly suggest that a heat-stable molecule might be responsible for the induction of cytokine production and O. tsutsugamushi might have mechanisms suppressing the production of inflammatory cytokines induced by its own heat-stable molecule.
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Affiliation(s)
- M K Kim
- Department of Microbiology, Inha University College of Medicine, Inchon 400-103, Republic of Korea
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42
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Moron CG, Popov VL, Feng HM, Wear D, Walker DH. Identification of the target cells of Orientia tsutsugamushi in human cases of scrub typhus. Mod Pathol 2001; 14:752-9. [PMID: 11504834 DOI: 10.1038/modpathol.3880385] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Orientia tsutsugamushi is the etiologic agent of scrub typhus, a chigger-borne zoonosis that is a highly prevalent, life-threatening illness of greatest public health importance in tropical Asia and the islands of the western Pacific Ocean. The target cell of this bacterium is poorly defined in humans. In this study, O. tsutsugamushi were identified by immunohistochemistry using a rabbit polyclonal antibody raised against O. tsutsugamushi Karp strain in paraffin-embedded archived autopsy tissues of three patients with clinical suspicion of scrub typhus who died during World War II and the Vietnam War. Rickettsiae were located in endothelial cells in all of the organs evaluated, namely heart, lung, brain, kidney, pancreas, and skin, and within cardiac muscle cells and in macrophages located in liver and spleen. Electron microscopy confirmed the location of rickettsiae in endothelium and cardiac myocytes.
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Affiliation(s)
- C G Moron
- Department of Pathology, University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555, USA
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43
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Cho NH, Seong SY, Choi MS, Kim IS. Expression of chemokine genes in human dermal microvascular endothelial cell lines infected with Orientia tsutsugamushi. Infect Immun 2001; 69:1265-72. [PMID: 11179287 PMCID: PMC98016 DOI: 10.1128/iai.69.3.1265-1272.2001] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Scrub typhus, caused by Orientia tsutsugamushi, is characterized by local as well as systemic inflammatory manifestations. The main pathologic change is focal or disseminated multiorgan vasculitis, which is caused by the destruction of endothelial cells and perivascular infiltration of leukocytes. We investigated the regulation of chemokine induction in transformed human dermal microvascular endothelial cells (HMEC-1) in response to O. tsutsugamushi infection. The monocyte chemoattractant protein-1 (MCP-1) and interleukin 8 (IL-8) mRNAs were induced, and their levels showed a transitory peak at 3 and 6 h, respectively. The RANTES transcript was detected at 6 h after infection, with increased levels evident by 48 h. The induction of the MCP-1 and IL-8 genes was not blocked by cycloheximide, suggesting that de novo protein synthesis of host cell proteins is not required for their transcriptional activation. Heat- or UV-inactivated O. tsutsugamushi induced a similar extent of MCP-1 and IL-8 responses. The induction of MCP-1 and IL-8 transcripts in the endothelial cells by O. tsutsugamushi was not blocked by the inhibitors of NF-kappaB. Furthermore, the activation of NF-kappaB was not detected in HMEC-1 stimulated with O. tsutsugamushi. These results demonstrate that heat-stable molecules of O. tsutsugamushi induce the MCP-1 and IL-8 genes and the induction of the chemokine genes may be mediated by an NF-kappaB independent mechanism. We also showed that another major transcription factor, activator protein-1 (AP-1), was up-regulated in HMEC-1 after O. tsutsugamushi infection. This suggests the possible involvement of AP-1 in the chemokine gene expression.
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Affiliation(s)
- N H Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine and Institute of Endemic Disease, Seoul National University Medical Research Center, Seoul 110-799, Republic of Korea
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Abstract
Orientia tsutsugamushi, an obligate intracellular bacterium, was isolated for the first time in 1930. Infections by virulent strains are characterized by fever, rash, eschar, pneumonia, myocarditis, and disseminated intravascular coagulation. Here we review the general aspects of O. tsutsugamushi and immune responses in terms of inflammation, protective immune mechanisms, and immunogenic antigens.
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Affiliation(s)
- S Y Seong
- Department of Microbiology and Immunology, Seoul National University College of Medicine and Institute of Endemic Disease, Seoul National University Medical Research Center, 28 Yongon-dong, Chongno-gu, 110-799, Seoul, South Korea
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Cho NH, Seong SY, Huh MS, Han TH, Koh YS, Choi MS, Kim IS. Expression of chemokine genes in murine macrophages infected with Orientia tsutsugamushi. Infect Immun 2000; 68:594-602. [PMID: 10639422 PMCID: PMC97181 DOI: 10.1128/iai.68.2.594-602.2000] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Scrub typhus, caused by Orientia tsutsugamushi infection, is characterized by local as well as systemic inflammatory manifestations. Inflammation is initiated by O. tsutsugamushi-infected macrophages and endothelial cells in the dermis. We investigated the regulation of chemokine induction in macrophage cell line J774A.1 in response to O. tsutsugamushi infection. The mRNAs for macrophage inflammatory proteins 1alpha/beta (MIP-1alpha/beta), MIP-2, and macrophage chemoattractant protein 1 were induced within 30 min, and their levels showed a transitory peak for 3 to 12 h. However, the lymphotactin, eotaxin, gamma interferon-inducible protein 10, and T-cell activation gene 3 mRNAs were not detected by RNase protection assays. Heat-killed O. tsutsugamushi induced a similar extent of chemokine responses. Induction of the chemokine genes was not blocked by the eukaryotic protein synthesis inhibitor cycloheximide, suggesting that de novo synthesis of host cell protein is not required for these transcriptional responses. The induction of chemokine mRNAs by O. tsutsugamushi was blocked by the inhibitors of NF-kappaB activation. Furthermore, O. tsutsugamushi induced the nuclear translocation and activation of NF-kappaB. These results demonstrate that heat-stable molecules of O. tsutsugamushi induce a subset of chemokine genes and that induction involves activation of the transcription factor NF-kappaB.
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Affiliation(s)
- N H Cho
- Department of Microbiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
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Ching WM, Wang H, Eamsila C, Kelly DJ, Dasch GA. Expression and refolding of truncated recombinant major outer membrane protein antigen (r56) of Orientia tsutsugamushi and its use in enzyme-linked immunosorbent assays. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1998; 5:519-26. [PMID: 9665960 PMCID: PMC95611 DOI: 10.1128/cdli.5.4.519-526.1998] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The variable 56-kDa major outer membrane protein of Orientia tsutsugamushi is the immunodominant antigen in human scrub typhus infections. The gene encoding this protein from Karp strain was cloned into the expression vector pET11a. The recombinant protein (r56) was expressed as a truncated nonfusion protein (amino acids 80 to 456 of the open reading frame) which formed an inclusion body when expressed in Escherichia coli BL21. Refolded r56 was purified and compared to purified whole-cell lysate of the Karp strain of O. tsutsugamushi by immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) for reactivity with rabbit sera prepared against eight antigenic prototypes of O. tsutsugamushi as well as several other species of Rickettsiales and nonrickettsial antigens. Refolded r56 exhibited broad reactivity with the rabbit antisera against the Orientia prototypes, and the ELISA reactions with the r56 and Karp whole-cell lysate antigens correlated well (r = 0.81, n = 22, sensitivity compared to that of standard ELISA of 91%). Refolded r56 did not react with most antisera against other rickettsial species or control antigens (specificity = 92%, n = 13) using a positive cutoff value determined with eight uninfected rabbit sera. Refolded r56 was evaluated further by ELISA, using 128 sera obtained from patients with suspected scrub typhus from Korat, Thailand, and 74 serum specimens from healthy Thai soldiers. By using the indirect immunoperoxidase assay as the reference assay, the recombinant antigen exhibited a sensitivity and specificity of 93% or greater for detection of both IgG and IgM in the ELISA at 1:400 serum dilution. These results strongly suggest that purified r56 is a suitable candidate for replacing the density gradient-purified, rickettsia-derived, whole-cell antigen currently used in the commercial dipstick assay available in the United States.
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Affiliation(s)
- W M Ching
- Viral and Rickettsial Diseases Program, Infectious Diseases Department, Naval Medical Research Institute, Bethesda, Maryland 20889-5607, USA.
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Amano KI, Williams JC, Dasch GA. Structural properties of lipopolysaccharides from Rickettsia typhi and Rickettsia prowazekii and their chemical similarity to the lipopolysaccharide from Proteus vulgaris OX19 used in the Weil-Felix test. Infect Immun 1998; 66:923-6. [PMID: 9488376 PMCID: PMC107996 DOI: 10.1128/iai.66.3.923-926.1998] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The lipopolysaccharides (LPSs) isolated from typhus group (TG) rickettsiae Rickettsia typhi and Rickettsia prowazekii were characterized by chemical analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by silver staining. LPSs from two species of TG rickettsiae contained glucose, 3-deoxy-D-manno-octulosonic acid, glucosamine, quinovosamine, phosphate, and fatty acids (beta-hydroxylmyristic acid and heneicosanoic acid) but not heptose. The O-polysaccharides of these LPSs were composed of glucose, glucosamine, quinovosamine, and phosphorylated hexosamine. Resolution of these LPSs by their apparent molecular masses by SDS-PAGE showed that they have a common ladder-like pattern. Based on the results of chemical composition and SDS-PAGE pattern, we suggest that these LPSs act as group-specific antigens. Furthermore, glucosamine, quinovosamine, and phosphorylated hexosamine were also found in the O-polysaccharide of the LPS from Proteus vulgaris OX19 used in the Weil-Felix test, suggesting that they may represent the antigens common to LPSs from TG rickettsiae and P. vulgaris OX19.
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Affiliation(s)
- K I Amano
- Airborne Diseases Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21701-5011, USA.
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Seong SY, Kim HR, Huh MS, Park SG, Kang JS, Han TH, Choi MS, Chang WH, Kim IS. Induction of neutralizing antibody in mice by immunization with recombinant 56 kDa protein of Orientia tsutsugamushi. Vaccine 1997; 15:1741-7. [PMID: 9364677 DOI: 10.1016/s0264-410x(97)00112-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Anti-oriential antibody inhibits Orientia tsutsugamushi attachment to, and penetration of, host cells. However, O. tsutsugamushi antigens that induce the production of a neutralizing antibody have not been identified. The authors immunized mice and rabbits with the recombinant 56 kDa protein of O. tsutsugamushi fused to the maltose binding protein of Escherichia coli (MBP-Bor56) and analysed their effect on O. tsutsugamushi attachment to or penetration of L929 cells. O. tsutsugamushi attachment and penetration were measured by using an indirect immunofluorescent antibody assay (IFA). O. tsutsugamushi growth in L929 cells was determined by [3H]thymidine uptake assay. By IFA, we observed a 96% reduction of attachment or penetration of O. tsutsugamushi treated with rabbit anti-MBP-Bor56 sera. [3H]thymidine uptake showed that mouse anti-MBP-Bor56 sera caused a 91% reduction in O. tsutsugamushi growth, when compared to mouse anti-MBP sera. These results suggest that the 56 kDa protein of O. tsutsugamushi plays an important role in O. tsutsugamushi attachment to or penetration of cells.
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Affiliation(s)
- S Y Seong
- Department of Microbiology, Seoul National University College of Medicine, Chongno-gu, South Korea
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Ohashi N, Koyama Y, Urakami H, Fukuhara M, Tamura A, Kawamori F, Yamamoto S, Kasuya S, Yoshimura K. Demonstration of antigenic and genotypic variation in Orientia tsutsugamushi which were isolated in Japan, and their classification into type and subtype. Microbiol Immunol 1996; 40:627-38. [PMID: 8908607 DOI: 10.1111/j.1348-0421.1996.tb01120.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A total of 40 strains of Orientia tsutsugamushi (34 isolates from patients and trombiculid mites in Japan, and 6 prototype strains of antigenic variants) were examined for classification based on the reactivities with type-specific monoclonal antibodies in indirect immunofluorescence tests, and on the restriction fragment length polymorphism of a polymerase chain reaction (PCR)-amplified 56-kilodalton type-specific antigenic protein gene. By these methods, several antigenic and genotypic variants were found among the strains, and these variants were classified into types and further into subtypes. These results suggest that there are many variants in O. tsutsugamushi, and the methods used here seem to be useful for the systematic classification of the numerous variants. A strain which may be a new type distinguishable from those identified previously was also found in this study. Furthermore, variety in the degree of pathogenicity in mice related to type and/or subtype classification were observed.
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Affiliation(s)
- N Ohashi
- Department of Microbiology, Niigata College of Pharmacy, Japan
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