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D'Souza C, Kishore U, Tsolaki AG. The PE-PPE Family of Mycobacterium tuberculosis: Proteins in Disguise. Immunobiology 2023; 228:152321. [PMID: 36805109 DOI: 10.1016/j.imbio.2022.152321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 12/31/2022]
Abstract
Mycobacterium tuberculosis has thrived in parallel with humans for millennia, and despite our efforts, M. tuberculosis continues to plague us, currently infecting a third of the world's population. The success of M. tuberculosis has recently been attributed, in part, to the PE-PPE family; a unique collection of 168 proteins fundamentally involved in the pathogenesis of M. tuberculosis. The PE-PPE family proteins have been at the forefront of intense research efforts since their discovery in 1998 and whilst our knowledge and understanding has significantly advanced over the last two decades, many important questions remain to be elucidated. This review consolidates and examines the vast body of existing literature regarding the PE-PPE family proteins, with respect to the latest developments in elucidating their evolution, structure, subcellular localisation, function, and immunogenicity. This review also highlights significant inconsistencies and contradictions within the field. Additionally, possible explanations for these knowledge gaps are explored. Lastly, this review poses many important questions, which need to be addressed to complete our understanding of the PE-PPE family, as well as highlighting the challenges associated with studying this enigmatic family of proteins. Further research into the PE-PPE family, together with technological advancements in genomics and proteomics, will undoubtedly improve our understanding of the pathogenesis of M. tuberculosis, as well as identify key targets/candidates for the development of novel drugs, diagnostics, and vaccines.
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Affiliation(s)
- Christopher D'Souza
- Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, United Kingdom
| | - Uday Kishore
- Department of Veterinary Medicine, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Anthony G Tsolaki
- Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, United Kingdom.
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2
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Host–Pathogen Interactions of Marine Gram-Positive Bacteria. BIOLOGY 2022; 11:biology11091316. [PMID: 36138795 PMCID: PMC9495620 DOI: 10.3390/biology11091316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary Complex interactions between marine Gram-positive pathogens and fish hosts in the marine environment can result in diseases of economically important finfish, which cause economic losses in the aquaculture industry. Understanding how these pathogens interact with the fish host and generate disease will contribute to efficient prophylactic measures and treatments. To our knowledge, there are no systematic reviews on marine Gram-positive pathogens. Therefore, here we reviewed the host–pathogen interactions of marine Gram-positive pathogens from the pathogen-centric and host-centric points of view. Abstract Marine Gram-positive bacterial pathogens, including Renibacterium salmoninarum, Mycobacterium marinum, Nocardia seriolae, Lactococcus garvieae, and Streptococcus spp. cause economic losses in marine fish aquaculture worldwide. Comprehensive information on these pathogens and their dynamic interactions with their respective fish–host systems are critical to developing effective prophylactic measures and treatments. While much is known about bacterial virulence and fish immune response, it is necessary to synthesize the knowledge in terms of host–pathogen interactions as a centerpiece to establish a crucial connection between the intricate details of marine Gram-positive pathogens and their fish hosts. Therefore, this review provides a holistic view and discusses the different stages of the host–pathogen interactions of marine Gram-positive pathogens. Gram-positive pathogens can invade fish tissues, evade the fish defenses, proliferate in the host system, and modulate the fish immune response. Marine Gram-positive pathogens have a unique set of virulence factors that facilitate adhesion (e.g., adhesins, hemagglutination activity, sortase, and capsules), invasion (e.g., toxins, hemolysins/cytolysins, the type VII secretion system, and immune-suppressive proteins), evasion (e.g., free radical quenching, actin-based motility, and the inhibition of phagolysosomal fusion), and proliferation and survival (e.g., heme utilization and siderophore-mediated iron acquisition systems) in the fish host. After infection, the fish host initiates specific innate and adaptive immune responses according to the extracellular or intracellular mechanism of infection. Although efforts have continued to be made in understanding the complex interplay at the host–pathogen interface, integrated omics-based investigations targeting host–pathogen–marine environment interactions hold promise for future research.
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Lagune M, Le Moigne V, Johansen MD, Vásquez Sotomayor F, Daher W, Petit C, Cosentino G, Paulowski L, Gutsmann T, Wilmanns M, Maurer FP, Herrmann JL, Girard-Misguich F, Kremer L. The ESX-4 substrates, EsxU and EsxT, modulate Mycobacterium abscessus fitness. PLoS Pathog 2022; 18:e1010771. [PMID: 35960766 PMCID: PMC9401124 DOI: 10.1371/journal.ppat.1010771] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 08/24/2022] [Accepted: 07/27/2022] [Indexed: 11/19/2022] Open
Abstract
ESX type VII secretion systems are complex secretion machineries spanning across the mycobacterial membrane and play an important role in pathogenicity, nutrient uptake and conjugation. We previously reported the role of ESX-4 in modulating Mycobacterium abscessus intracellular survival. The loss of EccB4 was associated with limited secretion of two effector proteins belonging to the WXG-100 family, EsxU and EsxT, and encoded by the esx-4 locus. This prompted us to investigate the function of M. abscessus EsxU and EsxT in vitro and in vivo. Herein, we show that EsxU and EsxT are substrates of ESX-4 and form a stable 1:1 heterodimer that permeabilizes artificial membranes. While expression of esxU and esxT was up-regulated in M. abscessus-infected macrophages, their absence in an esxUT deletion mutant prevented phagosomal membrane disruption while maintaining M. abscessus in an unacidified phagosome. Unexpectedly, the esxUT deletion was associated with a hyper-virulent phenotype, characterised by increased bacterial loads and mortality in mouse and zebrafish infection models. Collectively, these results demonstrate that the presence of EsxU and EsxT dampens survival and persistence of M. abscessus during infection.
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Affiliation(s)
- Marion Lagune
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
| | - Vincent Le Moigne
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
| | - Matt D. Johansen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
| | - Flor Vásquez Sotomayor
- National and WHO Supranational Reference Center for Mycobacteria, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Wassim Daher
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
- INSERM, IRIM, Montpellier, France
| | - Cécile Petit
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Gina Cosentino
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
| | - Laura Paulowski
- National and WHO Supranational Reference Center for Mycobacteria, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Thomas Gutsmann
- Research Center Borstel, Leibniz Lung Center, Division of Biophysics, Borstel, Germany
| | - Matthias Wilmanns
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
- * E-mail: (MW); (FPM); (J-LH); (FG-M); (LK)
| | - Florian P. Maurer
- National and WHO Supranational Reference Center for Mycobacteria, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- Institute of Medical Microbiology, Virology and Hospital Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail: (MW); (FPM); (J-LH); (FG-M); (LK)
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
- APHP, GHU Paris-Saclay, Hôpital Raymond Poincaré, Service de Microbiologie, Garches, France
- * E-mail: (MW); (FPM); (J-LH); (FG-M); (LK)
| | - Fabienne Girard-Misguich
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, Montigny-Le-Bretonneux, France
- * E-mail: (MW); (FPM); (J-LH); (FG-M); (LK)
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, Montpellier, France
- INSERM, IRIM, Montpellier, France
- * E-mail: (MW); (FPM); (J-LH); (FG-M); (LK)
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4
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Ferrell KC, Johansen MD, Triccas JA, Counoupas C. Virulence Mechanisms of Mycobacterium abscessus: Current Knowledge and Implications for Vaccine Design. Front Microbiol 2022; 13:842017. [PMID: 35308378 PMCID: PMC8928063 DOI: 10.3389/fmicb.2022.842017] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/08/2022] [Indexed: 12/22/2022] Open
Abstract
Mycobacterium abscessus is a member of the non-tuberculous mycobacteria (NTM) group, responsible for chronic infections in individuals with cystic fibrosis (CF) or those otherwise immunocompromised. While viewed traditionally as an opportunistic pathogen, increasing research into M. abscessus in recent years has highlighted its continued evolution into a true pathogen. This is demonstrated through an extensive collection of virulence factors (VFs) possessed by this organism which facilitate survival within the host, particularly in the harsh environment of the CF lung. These include VFs resembling those of other Mycobacteria, and non-mycobacterial VFs, both of which make a notable contribution in shaping M. abscessus interaction with the host. Mycobacterium abscessus continued acquisition of VFs is cause for concern and highlights the need for novel vaccination strategies to combat this pathogen. An effective M. abscessus vaccine must be suitably designed for target populations (i.e., individuals with CF) and incorporate current knowledge on immune correlates of protection against M. abscessus infection. Vaccination strategies must also build upon lessons learned from ongoing efforts to develop novel vaccines for other pathogens, particularly Mycobacterium tuberculosis (M. tb); decades of research into M. tb has provided insight into unconventional and innovative vaccine approaches that may be applied to M. abscessus. Continued research into M. abscessus pathogenesis will be critical for the future development of safe and effective vaccines and therapeutics to reduce global incidence of this emerging pathogen.
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Affiliation(s)
- Kia C. Ferrell
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Tuberculosis Research Program, Centenary Institute, Sydney, NSW, Australia
- *Correspondence: Kia C. Ferrell,
| | - Matt D. Johansen
- Centre for Inflammation, Centenary Institute, University of Technology, Sydney, NSW, Australia
- Faculty of Science, School of Life Sciences, University of Technology, Sydney, NSW, Australia
| | - James A. Triccas
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Sydney Institute for Infectious Diseases and the Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Claudio Counoupas
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
- Tuberculosis Research Program, Centenary Institute, Sydney, NSW, Australia
- Sydney Institute for Infectious Diseases and the Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- Claudio Counoupas,
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5
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Multiple genetic paths including massive gene amplification allow Mycobacterium tuberculosis to overcome loss of ESX-3 secretion system substrates. Proc Natl Acad Sci U S A 2022; 119:2112608119. [PMID: 35193958 PMCID: PMC8872769 DOI: 10.1073/pnas.2112608119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2021] [Indexed: 01/18/2023] Open
Abstract
The Mycobacterium tuberculosis (Mtb) ESX-3 type VII secretion system plays a critical role in iron acquisition. Infection of mice with highly attenuated Mtb deletion mutants lacking esxG or esxH, genes encoding key ESX-3 substrates, unexpectedly yielded suppressor mutants with restored capacity to grow in vivo and in vitro in the absence of iron supplementation. Whole-genome sequencing identified two mechanisms of suppression, the disruption of a transcriptional repressor that regulates expression of an ESX-3 paralogous region encoding EsxR and EsxS, and a massive 38- to 60-fold gene amplification of this same region. These data are significant because they reveal a previously unrecognized iron acquisition regulon and inform mechanisms of Mtb chromosome evolution. Mycobacterium tuberculosis (Mtb) possesses five type VII secretion systems (T7SS), virulence determinants that include the secretion apparatus and associated secretion substrates. Mtb strains deleted for the genes encoding substrates of the ESX-3 T7SS, esxG or esxH, require iron supplementation for in vitro growth and are highly attenuated in vivo. In a subset of infected mice, suppressor mutants of esxG or esxH deletions were isolated, which enabled growth to high titers or restored virulence. Suppression was conferred by mechanisms that cause overexpression of an ESX-3 paralogous region that lacks genes for the secretion apparatus but encodes EsxR and EsxS, apparent ESX-3 orphan substrates that functionally compensate for the lack of EsxG or EsxH. The mechanisms include the disruption of a transcriptional repressor and a massive 38- to 60-fold gene amplification. These data identify an iron acquisition regulon, provide insight into T7SS, and reveal a mechanism of Mtb chromosome evolution involving “accordion-type” amplification.
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Abstract
Mycobacterium tuberculosis infections claim more than a million lives each year, and better treatments or vaccines are required. A crucial pathogenicity factor is translocation from phagolysosomes to the cytosol upon phagocytosis by macrophages. Translocation from the phagolysosome to the cytosol is an ESX-1-dependent process, as previously shown in vitro Here, we show that in vivo, mycobacteria also translocate to the cytosol but mainly when host immunity is compromised. We observed only low numbers of cytosolic bacilli in mice, armadillos, zebrafish, and patient material infected with M. tuberculosis, M. marinum, or M. leprae In contrast, when innate or adaptive immunity was compromised, as in severe combined immunodeficiency (SCID) or interleukin-1 receptor 1 (IL-1R1)-deficient mice, significant numbers of cytosolic M. tuberculosis bacilli were detected in the lungs of infected mice. Taken together, in vivo, translocation to the cytosol of M. tuberculosis is controlled by adaptive immune responses as well as IL-1R1-mediated signals.IMPORTANCE For decades, Mycobacterium tuberculosis has been one of the deadliest pathogens known. Despite infecting approximately one-third of the human population, no effective treatment or vaccine is available. A crucial pathogenicity factor is subcellular localization, as M. tuberculosis can translocate from phagolysosome to the cytosol in macrophages. The situation in vivo is more complicated. In this study, we establish that high-level cytosolic escape of mycobacteria can indeed occur in vivo but mainly when host resistance is compromised. The IL-1 pathway is crucial for the control of the number of cytosolic mycobacteria. The establishment that immune signals result in the clearance of cells containing cytosolic mycobacteria connects two important fields, cell biology and immunology, which is vital for the understanding of the pathology of M. tuberculosis.
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7
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Tiwari S, Dutt TS, Chen B, Chen M, Kim J, Dai AZ, Lukose R, Shanley C, Fox A, Karger BR, Porcelli SA, Chan J, Podell BK, Obregon-Henao A, Orme IM, Jacobs WR, Henao-Tamayo M. BCG-Prime and boost with Esx-5 secretion system deletion mutant leads to better protection against clinical strains of Mycobacterium tuberculosis. Vaccine 2020; 38:7156-7165. [PMID: 32978002 PMCID: PMC7755135 DOI: 10.1016/j.vaccine.2020.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/07/2020] [Accepted: 08/03/2020] [Indexed: 10/23/2022]
Abstract
Although vaccination with BCG prevents disseminated forms of childhood tuberculosis (TB), it does not protect against pulmonary infection or Mycobacterium tuberculosis (Mtb) transmission. In this study, we generated a complete deletion mutant of the Mtb Esx-5 type VII secretion system (Mtb Δesx-5). Mtb Δesx-5 was highly attenuated and safe in immunocompromised mice. When tested as a vaccine candidate to boost BCG-primed immunity, Mtb Δesx-5 improved protection against highly virulent Mtb strains in the murine and guinea pig models of TB. Enhanced protection provided by heterologous BCG-prime plus Mtb Δesx-5 boost regimen was associated with increased pulmonary influx of central memory T cells (TCM), follicular helper T cells (TFH) and activated monocytes. Conversely, lower numbers of T cells expressing exhaustion markers were observed in vaccinated animals. Our results suggest that boosting BCG-primed immunity with Mtb Δesx-5 is a potential approach to improve protective immunity against Mtb. Further insight into the mechanism of action of this novel prime-boost approach is warranted.
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Affiliation(s)
- Sangeeta Tiwari
- Department of Biological Sciences & Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, United States.
| | - Taru S Dutt
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States
| | - Bing Chen
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Mei Chen
- Department of Biological Sciences & Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, United States; Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - John Kim
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Annie Zhi Dai
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Regy Lukose
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Crystal Shanley
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States
| | - Amy Fox
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States
| | - Burton R Karger
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States
| | - Steven A Porcelli
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States; Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - John Chan
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States; Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Brendan K Podell
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States
| | - Andres Obregon-Henao
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States
| | - Ian M Orme
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States
| | - William R Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
| | - Marcela Henao-Tamayo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States.
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Mycobacteriosis and Infections with Non-tuberculous Mycobacteria in Aquatic Organisms: A Review. Microorganisms 2020; 8:microorganisms8091368. [PMID: 32906655 PMCID: PMC7564596 DOI: 10.3390/microorganisms8091368] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/02/2020] [Accepted: 09/04/2020] [Indexed: 12/19/2022] Open
Abstract
The Mycobacteriaceae constitute a family of varied Gram-positive organisms that include a large number of pathogenic bacteria. Among these, non-tuberculous mycobacteria are endemic worldwide and have been associated with infections in a large number of organisms, including humans and other mammals and reptiles, as well as fish. In this review, we summarize the most recent findings regarding this group of pathogens in fish. There, four species are most commonly associated with disease outbreaks: Mycobacterium marinum, the most common of these fish mycobacterial pathogens, Mycobacterium fortuitum, Mycobacterium gordonae, and Mycobacterium chelonae. These bacteria have a broad host range: they are zoonotic, and infections have been reported in a large number of fish species. The main route of entry of the bacterium into the fish is through the gastrointestinal route, and the disease is associated with ulcerative dermatitis as well as organomegaly and the development of granulomatous lesions in the internal organs. Mycobacteriaceae are slow-growing and fastidious and isolation is difficult and time consuming and diagnostic is mostly performed using serological and molecular tools. Control of the disease is also difficult: there is currently no effective vaccine and infections react poorly to antibiotherapy. For this reason, more research is needed on the subject of these vexing pathogens.
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Damen MPM, Phan TH, Ummels R, Rubio-Canalejas A, Bitter W, Houben ENG. Modification of a PE/PPE substrate pair reroutes an Esx substrate pair from the mycobacterial ESX-1 type VII secretion system to the ESX-5 system. J Biol Chem 2020; 295:5960-5969. [PMID: 32184351 DOI: 10.1074/jbc.ra119.011682] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/13/2020] [Indexed: 01/20/2023] Open
Abstract
Bacterial type VII secretion systems secrete a wide range of extracellular proteins that play important roles in bacterial viability and in interactions of pathogenic mycobacteria with their hosts. Mycobacterial type VII secretion systems consist of five subtypes, ESX-1-5, and have four substrate classes, namely, Esx, PE, PPE, and Esp proteins. At least some of these substrates are secreted as heterodimers. Each ESX system mediates the secretion of a specific set of Esx, PE, and PPE proteins, raising the question of how these substrates are recognized in a system-specific fashion. For the PE/PPE heterodimers, it has been shown that they interact with their cognate EspG chaperone and that this chaperone determines the designated secretion pathway. However, both structural and pulldown analyses have suggested that EspG cannot interact with the Esx proteins. Therefore, the determining factor for system specificity of the Esx proteins remains unknown. Here, we investigated the secretion specificity of the ESX-1 substrate pair EsxB_1/EsxA_1 in Mycobacterium marinum Although this substrate pair was hardly secreted when homologously expressed, it was secreted when co-expressed together with the PE35/PPE68_1 pair, indicating that this pair could stimulate secretion of the EsxB_1/EsxA_1 pair. Surprisingly, co-expression of EsxB_1/EsxA_1 with a modified PE35/PPE68_1 version that carried the EspG5 chaperone-binding domain, previously shown to redirect this substrate pair to the ESX-5 system, also resulted in redirection and co-secretion of the Esx pair via ESX-5. Our results suggest a secretion model in which PE35/PPE68_1 determines the system-specific secretion of EsxB_1/EsxA_1.
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Affiliation(s)
- Merel P M Damen
- Section Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Trang H Phan
- Section Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Roy Ummels
- Department of Medical Microbiology and Infection Control, Amsterdam Infection & Immunity Institute, Amsterdam University Medical Centers, 1081 HV Amsterdam, The Netherlands
| | - Alba Rubio-Canalejas
- Section Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, Amsterdam Infection & Immunity Institute, Amsterdam University Medical Centers, 1081 HV Amsterdam, The Netherlands
| | - Edith N G Houben
- Section Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.
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10
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Wang S, Zhou K, Yang X, Zhang B, Zhao Y, Xiao Y, Yang X, Yang H, Guddat LW, Li J, Rao Z. Structural insights into substrate recognition by the type VII secretion system. Protein Cell 2020; 11:124-137. [PMID: 31758528 PMCID: PMC6954902 DOI: 10.1007/s13238-019-00671-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/02/2019] [Indexed: 01/07/2023] Open
Abstract
Type VII secretion systems (T7SSs) are found in many disease related bacteria including Mycobacterium tuberculosis (Mtb). ESX-1 [early secreted antigen 6 kilodaltons (ESAT-6) system 1] is one of the five subtypes (ESX-1~5) of T7SSs in Mtb, where it delivers virulence factors into host macrophages during infection. However, little is known about the molecular details as to how this occurs. Here, we provide high-resolution crystal structures of the C-terminal ATPase3 domains of EccC subunits from four different Mtb T7SS subtypes. These structures adopt a classic RecA-like ɑ/β fold with a conserved Mg-ATP binding site. The structure of EccCb1 in complex with the C-terminal peptide of EsxB identifies the location of substrate recognition site and shows how the specific signaling module "LxxxMxF" for Mtb ESX-1 binds to this site resulting in a translation of the bulge loop. A comparison of all the ATPase3 structures shows there are significant differences in the shape and composition of the signal recognition pockets across the family, suggesting that distinct signaling sequences of substrates are required to be specifically recognized by different T7SSs. A hexameric model of the EccC-ATPase3 is proposed and shows the recognition pocket is located near the central substrate translocation channel. The diameter of the channel is ~25-Å, with a size that would allow helix-bundle shaped substrate proteins to bind and pass through. Thus, our work provides new molecular insights into substrate recognition for Mtb T7SS subtypes and also a possible transportation mechanism for substrate and/or virulence factor secretion.
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Affiliation(s)
- Shuhui Wang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China ,CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031 China ,University of Chinese Academy of Sciences, Beijing, 100101 China
| | - Kaixuan Zhou
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences and College of Pharmacy, Nankai University, Tianjin, 300353 China
| | - Xiaolin Yang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China ,CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031 China ,University of Chinese Academy of Sciences, Beijing, 100101 China
| | - Bing Zhang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China ,CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031 China ,University of Chinese Academy of Sciences, Beijing, 100101 China
| | - Yao Zhao
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China ,CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031 China ,University of Chinese Academy of Sciences, Beijing, 100101 China
| | - Yu Xiao
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China ,CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 200031 China ,University of Chinese Academy of Sciences, Beijing, 100101 China
| | - Xiuna Yang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China
| | - Haitao Yang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China
| | - Luke W. Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Jun Li
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China
| | - Zihe Rao
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China ,State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences and College of Pharmacy, Nankai University, Tianjin, 300353 China ,Laboratory of Structural Biology, Tsinghua University, Beijing, 100084 China ,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
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11
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Ates LS. New insights into the mycobacterial PE and PPE proteins provide a framework for future research. Mol Microbiol 2020; 113:4-21. [PMID: 31661176 PMCID: PMC7028111 DOI: 10.1111/mmi.14409] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2019] [Indexed: 12/30/2022]
Abstract
The PE and PPE proteins of Mycobacterium tuberculosis have been studied with great interest since their discovery. Named after the conserved proline (P) and glutamic acid (E) residues in their N-terminal domains, these proteins are postulated to perform wide-ranging roles in virulence and immune modulation. However, technical challenges in studying these proteins and their encoding genes have hampered the elucidation of molecular mechanisms and leave many open questions regarding the biological functions mediated by these proteins. Here, I review the shared and unique characteristics of PE and PPE proteins from a molecular perspective linking this information to their functions in mycobacterial virulence. I discuss how the different subgroups (PE_PGRS, PPE-PPW, PPE-SVP and PPE-MPTR) are defined and why this classification of paramount importance to understand the PE and PPE proteins as individuals and or groups. The goal of this MicroReview is to summarize and structure the existing information on this gene family into a simplified framework of thinking about PE and PPE proteins and genes. Thereby, I hope to provide helpful starting points in studying these genes and proteins for researchers with different backgrounds. This has particular implications for the design and monitoring of novel vaccine candidates and in understanding the evolution of the M. tuberculosis complex.
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Affiliation(s)
- Louis S. Ates
- Department of Experimental ImmunologyAmsterdam Infection & Immunity InstituteAmsterdam UMCUniversity of AmsterdamMeibergdreef 9Amsterdamthe Netherlands
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12
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Biomarkers for Detecting Resilience against Mycobacterial Disease in Animals. Infect Immun 2019; 88:IAI.00401-19. [PMID: 31527123 DOI: 10.1128/iai.00401-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Paratuberculosis and bovine tuberculosis are two mycobacterial diseases of ruminants which have a considerable impact on livestock health, welfare, and production. These are chronic "iceberg" diseases which take years to manifest and in which many subclinical cases remain undetected. Suggested biomarkers to detect infected or diseased animals are numerous and include cytokines, peptides, and expression of specific genes; however, these do not provide a strong correlation to disease. Despite these advances, disease detection still relies heavily on dated methods such as detection of pathogen shedding, skin tests, or serology. Here we review the evidence for suitable biomarkers and their mechanisms of action, with a focus on identifying animals that are resilient to disease. A better understanding of these factors will help establish new strategies to control the spread of these diseases.
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13
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Cheng T, Kam JY, Johansen MD, Oehlers SH. High content analysis of granuloma histology and neutrophilic inflammation in adult zebrafish infected with Mycobacterium marinum. Micron 2019; 129:102782. [PMID: 31775097 DOI: 10.1016/j.micron.2019.102782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/11/2019] [Accepted: 11/13/2019] [Indexed: 12/20/2022]
Abstract
Infection of zebrafish with natural pathogen Mycobacterium marinum is a useful surrogate for studying the human granulomatous inflammatory response to infection by Mycobacterium tuberculosis. The adaptive immune system of the adult stage zebrafish offers an advance on the commonly used embryo infection model as adult zebrafish form granulomas with striking similarities to human-M. tuberculosis granulomas. Here, we present workflows to perform high content analyses of granulomas in adult zebrafish infected with M. marinum by cryosectioning to take advantage of strong endogenous transgenic fluorescence adapted from common zebrafish embryo infection tools. Specific guides to classifying granuloma necrosis and organisation, quantifying bacterial burden and leukocyte infiltration of granulomas, visualizing foam cell formation, analysing extracellular matrix remodelling and granuloma fibrosis are also provided. We use these methods to characterize neutrophil recruitment to M. marinum granulomas across time and find an inverse relation to granuloma necrosis suggesting granuloma necrosis is not a marker of immunopathology in the natural infection system of the adult zebrafish-M. marinum pairing. The methods can be easily translated to studying the zebrafish adaptive immune response to other chronic and granuloma-forming pathogens.
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Affiliation(s)
- Tina Cheng
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Julia Y Kam
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Matt D Johansen
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Stefan H Oehlers
- Tuberculosis Research Program at the Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia; The University of Sydney, Discipline of Infectious Diseases & Immunology and Marie Bashir Institute, Camperdown, NSW, 2050, Australia.
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14
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Madacki J, Mas Fiol G, Brosch R. Update on the virulence factors of the obligate pathogen Mycobacterium tuberculosis and related tuberculosis-causing mycobacteria. INFECTION GENETICS AND EVOLUTION 2019; 72:67-77. [DOI: 10.1016/j.meegid.2018.12.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/02/2018] [Accepted: 12/07/2018] [Indexed: 12/21/2022]
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15
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Hodgkinson JW, Belosevic M, Elks PM, Barreda DR. Teleost contributions to the understanding of mycobacterial diseases. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 96:111-125. [PMID: 30776420 DOI: 10.1016/j.dci.2019.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 02/15/2019] [Accepted: 02/15/2019] [Indexed: 06/09/2023]
Abstract
Few pathogens have shaped human medicine as the mycobacteria. From understanding biological phenomena driving disease spread, to mechanisms of host-pathogen interactions and antibiotic resistance, the Mycobacterium genus continues to challenge and offer insights into the basis of health and disease. Teleost fish models of mycobacterial infections have progressed significantly over the past three decades, now supplying a range of unique tools and new opportunities to define the strategies employed by these Gram-positive bacteria to overcome host defenses, as well as those host antimicrobial pathways that can be used to limit its growth and spread. Herein, we take a comparative perspective and provide an update on the contributions of teleost models to our understanding of mycobacterial diseases.
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Affiliation(s)
- Jordan W Hodgkinson
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Miodrag Belosevic
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Philip M Elks
- The Bateson Centre, University of Sheffield, Western Bank, Sheffield, United Kingdom; Department of Infection and Immunity and Cardiovascular Disease, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Daniel R Barreda
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
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16
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A Mycobacterium tuberculosis surface protein recruits ubiquitin to trigger host xenophagy. Nat Commun 2019; 10:1973. [PMID: 31036822 PMCID: PMC6488588 DOI: 10.1038/s41467-019-09955-8] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 04/01/2019] [Indexed: 01/03/2023] Open
Abstract
Ubiquitin-mediated xenophagy, a type of selective autophagy, plays crucial roles in host defense against intracellular pathogens including Mycobacterium tuberculosis (Mtb). However, the exact mechanism by which host ubiquitin targets invaded microbes to trigger xenophagy remains obscure. Here we show that ubiquitin could recognize Mtb surface protein Rv1468c, a previously unidentified ubiquitin-binding protein containing a eukaryotic-like ubiquitin-associated (UBA) domain. The UBA-mediated direct binding of ubiquitin to, but not E3 ubiquitin ligases-mediated ubiquitination of, Rv1468c recruits autophagy receptor p62 to deliver mycobacteria into LC3-associated autophagosomes. Disruption of Rv1468c-ubiquitin interaction attenuates xenophagic clearance of Mtb in macrophages, and increases bacterial loads in mice with elevated inflammatory responses. Together, our findings reveal a unique mechanism of host xenophagy triggered by direct binding of ubiquitin to the pathogen surface protein, and indicate a diplomatic strategy adopted by Mtb to benefit its persistent intracellular infection through controlling intracellular bacterial loads and restricting host inflammatory responses. Ubiquitin (Ub)-mediated xenophagy is important in defense against Mycobacterium tuberculosis (Mtb). Here, Chai et al. describe autophagy triggering by Ub binding to the Mtb surface protein Rv1468c, and show that its deletion leads to increased bacterial loads and hyperinflammatory responses in mice.
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17
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Hashish E, Merwad A, Elgaml S, Amer A, Kamal H, Elsadek A, Marei A, Sitohy M. Mycobacterium marinum infection in fish and man: epidemiology, pathophysiology and management; a review. Vet Q 2018; 38:35-46. [PMID: 29493404 PMCID: PMC6831007 DOI: 10.1080/01652176.2018.1447171] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Mycobacterium marinum is an opportunistic pathogen inducing infection in fresh and marine water fish. This pathogen causes necrotizing granuloma like tuberculosis, morbidity and mortality in fish. The cell wall-associated lipid phthiocerol dimycocerosates, phenolic glycolipids and ESAT-6 secretion system 1 (ESX-1) are the conserved virulence determinant of the organism. Human infections with Mycobacterium marinum hypothetically are classified into four clinical categories (type I–type IV) and have been associated with the exposure of damaged skin to polluted water from fish pools or contacting objects contaminated with infected fish. Fish mycobacteriosis is clinically manifested and characterized in man by purple painless nodules, liable to develop into superficial crusting ulceration with scar formation. Early laboratory diagnosis of M. marinum including histopathology, culture and PCR is essential and critical as the clinical response to antibiotics requires months to be attained. The pathogenicity and virulence determinants of M. marinum need to be thoroughly and comprehensively investigated and understood. In spite of accumulating information on this pathogen, the different relevant data should be compared, connected and globally compiled. This article is reviewing the epidemiology, virulence factors, diagnosis and disease management in fish while casting light on the potential associated public health hazards.
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Affiliation(s)
- Emad Hashish
- a Department of Clinical Pathology, Faculty of Veterinary Medicine , Zagazig University , Egypt
| | - Abdallah Merwad
- b Department of Zoonoses, Faculty of Veterinary Medicine , Zagazig University , Egypt
| | - Shimaa Elgaml
- a Department of Clinical Pathology, Faculty of Veterinary Medicine , Zagazig University , Egypt
| | - Ali Amer
- c Tuberculosis Unit , Animal Health Research Institute (AHRI) , Giza , Egypt
| | - Huda Kamal
- d Department of Meat Hygiene , National Research Center (NRC) , Zagazig , Egypt
| | - Ahmed Elsadek
- e Immunology Research Lab, Immunology Division, Department of Microbiology and Immunology, Faculty of Medicine , Zagazig University , Egypt
| | - Ayman Marei
- e Immunology Research Lab, Immunology Division, Department of Microbiology and Immunology, Faculty of Medicine , Zagazig University , Egypt
| | - Mahmoud Sitohy
- f Department of Biochemistry, Faculty of Agriculture , Zagazig University , Egypt
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18
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De Maio F, Battah B, Palmieri V, Petrone L, Corrente F, Salustri A, Palucci I, Bellesi S, Papi M, Rubino S, Sali M, Goletti D, Sanguinetti M, Manganelli R, De Spirito M, Delogu G. PE_PGRS3 of Mycobacterium tuberculosis is specifically expressed at low phosphate concentration, and its arginine-rich C-terminal domain mediates adhesion and persistence in host tissues when expressed in Mycobacterium smegmatis. Cell Microbiol 2018; 20:e12952. [PMID: 30192424 DOI: 10.1111/cmi.12952] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 08/22/2018] [Accepted: 08/28/2018] [Indexed: 12/14/2022]
Abstract
PE_PGRSs of Mycobacterium tuberculosis (Mtb) represent a family of complex and peculiar proteins whose role and function remain elusive. In this study, we investigated PE_PGRS3 and PE_PGRS4, two highly homologous PE_PGRSs encoded by two contiguous genes in the Mtb genome. Using a gene-reporter system in Mycobacterium smegmatis (Ms) and transcriptional analysis in Mtb, we show that PE_PGRS3, but not PE_PGRS4, is specifically expressed under low phosphate concentrations. Interestingly, PE_PGRS3, but not PE_PGRS4, has a unique, arginine-rich C-terminal domain of unknown function. Heterologous expression of PE_PGRS3 in Ms was used to demonstrate cellular localisation of the protein on the mycobacterial surface, where it significantly affects net surface charge. Moreover, expression of full-length PE_PGRS3 enhanced adhesion of Ms to murine macrophages and human epithelial cells and improved bacterial persistence in spleen tissue following infection in mice. Expression of the PE_PGRS3 functional deletion mutant lacking the C-terminal domain in Ms did not enhance adhesion to host cells, showing a phenotype similar to the Ms parental strain. Interestingly, enhanced persistence of Ms expressing PE_PGRS3 did not correlate with increased concentrations of inflammatory cytokines. These results point to a critical role for the ≈ 80 amino acids long, arginine-rich C-terminal domain of PE_PGRS3 in tuberculosis pathogenesis.
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Affiliation(s)
- Flavio De Maio
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Basem Battah
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy.,Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Valentina Palmieri
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Linda Petrone
- Translational Research Unit, Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases, Rome, Italy
| | - Francesco Corrente
- Institute of Haematology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Alessandro Salustri
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ivana Palucci
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Silvia Bellesi
- Institute of Haematology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Massimiliano Papi
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Salvatore Rubino
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Michela Sali
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Delia Goletti
- Translational Research Unit, Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases, Rome, Italy
| | - Maurizio Sanguinetti
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Marco De Spirito
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Giovanni Delogu
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
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19
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Extensive genomic diversity among Mycobacterium marinum strains revealed by whole genome sequencing. Sci Rep 2018; 8:12040. [PMID: 30104693 PMCID: PMC6089878 DOI: 10.1038/s41598-018-30152-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 07/25/2018] [Indexed: 12/20/2022] Open
Abstract
Mycobacterium marinum is the causative agent for the tuberculosis-like disease mycobacteriosis in fish and skin lesions in humans. Ubiquitous in its geographical distribution, M. marinum is known to occupy diverse fish as hosts. However, information about its genomic diversity is limited. Here, we provide the genome sequences for 15 M. marinum strains isolated from infected humans and fish. Comparative genomic analysis of these and four available genomes of the M. marinum strains M, E11, MB2 and Europe reveal high genomic diversity among the strains, leading to the conclusion that M. marinum should be divided into two different clusters, the "M"- and the "Aronson"-type. We suggest that these two clusters should be considered to represent two M. marinum subspecies. Our data also show that the M. marinum pan-genome for both groups is open and expanding and we provide data showing high number of mutational hotspots in M. marinum relative to other mycobacteria such as Mycobacterium tuberculosis. This high genomic diversity might be related to the ability of M. marinum to occupy different ecological niches.
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20
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Munang'andu HM. Intracellular Bacterial Infections: A Challenge for Developing Cellular Mediated Immunity Vaccines for Farmed Fish. Microorganisms 2018; 6:microorganisms6020033. [PMID: 29690563 PMCID: PMC6027125 DOI: 10.3390/microorganisms6020033] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/15/2018] [Accepted: 04/20/2018] [Indexed: 12/15/2022] Open
Abstract
Aquaculture is one of the most rapidly expanding farming systems in the world. Its rapid expansion has brought with it several pathogens infecting different fish species. As a result, there has been a corresponding expansion in vaccine development to cope with the increasing number of infectious diseases in aquaculture. The success of vaccine development for bacterial diseases in aquaculture is largely attributed to empirical vaccine designs based on inactivation of whole cell (WCI) bacteria vaccines. However, an upcoming challenge in vaccine design is the increase of intracellular bacterial pathogens that are not responsive to WCI vaccines. Intracellular bacterial vaccines evoke cellular mediated immune (CMI) responses that “kill” and eliminate infected cells, unlike WCI vaccines that induce humoral immune responses whose protective mechanism is neutralization of extracellular replicating pathogens by antibodies. In this synopsis, I provide an overview of the intracellular bacterial pathogens infecting different fish species in aquaculture, outlining their mechanisms of invasion, replication, and survival intracellularly based on existing data. I also bring into perspective the current state of CMI understanding in fish together with its potential application in vaccine development. Further, I highlight the immunological pitfalls that have derailed our ability to produce protective vaccines against intracellular pathogens for finfish. Overall, the synopsis put forth herein advocates for a shift in vaccine design to include CMI-based vaccines against intracellular pathogens currently adversely affecting the aquaculture industry.
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Affiliation(s)
- Hetron Mweemba Munang'andu
- Section of Aquatic Medicine and Nutrition, Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Ullevålsveien 72, P.O. Box 8146, Dep NO-0033, 046 Oslo, Norway.
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21
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Ates LS, Dippenaar A, Ummels R, Piersma SR, van der Woude AD, van der Kuij K, Le Chevalier F, Mata-Espinosa D, Barrios-Payán J, Marquina-Castillo B, Guapillo C, Jiménez CR, Pain A, Houben ENG, Warren RM, Brosch R, Hernández-Pando R, Bitter W. Mutations in ppe38 block PE_PGRS secretion and increase virulence of Mycobacterium tuberculosis. Nat Microbiol 2018; 3:181-188. [DOI: 10.1038/s41564-017-0090-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/29/2017] [Indexed: 12/30/2022]
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Abstract
ABSTRACT
Mycobacterium marinum
is a well-known pathogenic mycobacterium for skin and soft tissue infections and is associated with fishes and water. Among nontuberculous mycobacteria (NTM), it is the leading cause of extrarespiratory human infections worldwide. In addition, there is a specific scientific interest in
M. marinum
because of its genetic relatedness to
Mycobacterium tuberculosis
and because experimental infection of
M. marinum
in fishes mimics tuberculosis pathogenesis. Microbiological characteristics include the fact that it grows in 7 to 14 days with photochromogenic colonies and is difficult to differentiate from
Mycobacterium ulcerans
and other mycolactone-producing NTM on a molecular basis. The diagnosis is highly suspected by the mode of infection, which is related to the hobby of fishkeeping, professional handling of marine shells, or swimming in nonchlorinated pools. Clinics distinguished skin and soft tissue lesions (typically sporotrichoid or subacute hand nodules) and lesions disseminated to joint and bone, often related with the local use of corticosteroids. In clinical microbiology, microscopy and culture are often negative because growth requires low temperature (30°C) and several weeks to succeed in primary cultivation. The treatment is not standardized, and no randomized control trials have been done. Therapy is a combination of surgery and antimicrobial agents such as cyclines and rifampin, with successful outcome in most of the skin diseases but less frequently in deep tissue infections. Prevention can be useful with hand protection recommendations for professionals and all persons manipulating fishes or fish tank water and use of alcohol disinfection after contact.
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Abstract
Type VII secretion (T7S) systems of mycobacteria secrete substrates over the unusual diderm cell envelope. Furthermore, T7S gene clusters are present throughout the phylum Actinobacteria, and functional T7S-like systems have been identified in Firmicutes. Most of the T7S substrates can be divided into two families: the Esx proteins, which are found in both Firmicutes and Actinobacteria, and the PE and PPE proteins, which are more mycobacterium-specific. Members of both families have been shown to be secreted as folded heterodimers, suggesting that this is a conserved feature of T7S substrates. Most knowledge of the mechanism of T7S and the roles of T7S systems in virulence comes from studies of pathogenic mycobacteria. These bacteria can contain up to five T7S systems, called ESX-1 to ESX-5, each having its own role in bacterial physiology and virulence. In this article, we discuss the general composition of T7S systems and the role of the individual components in secretion. These conserved components include two membrane proteins with (predicted) enzymatic activities: a predicted ATPase (EccC), likely to be required for energy provision of T7S, and a subtilisin-like protease (MycP) involved in processing of specific substrates. Additionally, we describe the role of a conserved intracellular chaperone in T7S substrate recognition, based on recently published crystal structures and molecular analysis. Finally, we discuss system-specific features of the different T7S systems in mycobacteria and their role in pathogenesis and provide an overview of the role of T7S in virulence of other pathogenic bacteria.
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24
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Abstract
Mycobacterium tuberculosis uses sophisticated secretion systems, named 6 kDa early secretory antigenic target (ESAT6) protein family secretion (ESX) systems (also known as type VII secretion systems), to export a set of effector proteins that helps the pathogen to resist or evade the host immune response. Since the discovery of the esx loci during the M. tuberculosis H37Rv genome project, structural biology, cell biology and evolutionary analyses have advanced our knowledge of the function of these systems. In this Review, we highlight the intriguing roles that these studies have revealed for ESX systems in bacterial survival and pathogenicity during infection with M. tuberculosis. Furthermore, we discuss the diversity of ESX systems that has been described among mycobacteria and selected non-mycobacterial species. Finally, we consider how our knowledge of ESX systems might be applied to the development of novel strategies for the treatment and prevention of disease.
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25
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Collymore C, Crim MJ, Lieggi C. Recommendations for Health Monitoring and Reporting for Zebrafish Research Facilities. Zebrafish 2016; 13 Suppl 1:S138-48. [PMID: 26991393 PMCID: PMC4932782 DOI: 10.1089/zeb.2015.1210] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The presence of subclinical infection or clinical disease in laboratory zebrafish may have a significant impact on research results, animal health and welfare, and transfer of animals between institutions. As use of zebrafish as a model of disease increases, a harmonized method for monitoring and reporting the health status of animals will facilitate the transfer of animals, allow institutions to exclude diseases that may negatively impact their research programs, and improve animal health and welfare. All zebrafish facilities should implement a health monitoring program. In this study, we review important aspects of a health monitoring program, including choice of agents, samples for testing, available testing methodologies, housing and husbandry, cost, test subjects, and a harmonized method for reporting results. Facilities may use these recommendations to implement their own health monitoring program.
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Affiliation(s)
- Chereen Collymore
- Division of Comparative Medicine, University of Toronto, Toronto, Ontario, Canada
| | | | - Christine Lieggi
- Center for Comparative Medicine and Pathology, Weill Cornell Medical College and Memorial Sloan Kettering Cancer Center, New York, New York
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26
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Ates LS, van der Woude AD, Bestebroer J, van Stempvoort G, Musters RJP, Garcia-Vallejo JJ, Picavet DI, Weerd RVD, Maletta M, Kuijl CP, van der Wel NN, Bitter W. The ESX-5 System of Pathogenic Mycobacteria Is Involved In Capsule Integrity and Virulence through Its Substrate PPE10. PLoS Pathog 2016; 12:e1005696. [PMID: 27280885 PMCID: PMC4900558 DOI: 10.1371/journal.ppat.1005696] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 05/20/2016] [Indexed: 11/18/2022] Open
Abstract
Mycobacteria produce a capsule layer, which consists of glycan-like polysaccharides and a number of specific proteins. In this study, we show that, in slow-growing mycobacteria, the type VII secretion system ESX-5 plays a major role in the integrity and stability of the capsule. We have identified PPE10 as the ESX-5 substrate responsible for this effect. Mutants in esx-5 and ppe10 both have impaired capsule integrity as well as reduced surface hydrophobicity. Electron microscopy, immunoblot and flow cytometry analyses demonstrated reduced amounts of surface localized proteins and glycolipids, and morphological differences in the capsular layer. Since capsular proteins secreted by the ESX-1 system are important virulence factors, we tested the effect of the mutations that cause capsular defects on virulence mechanisms. Both esx-5 and ppe10 mutants of Mycobacterium marinum were shown to be impaired in ESX-1-dependent hemolysis. In agreement with this, the ppe10 and esx5 mutants showed reduced recruitment of ubiquitin in early macrophage infection and intermediate attenuation in zebrafish embryos. These results provide a pivotal role for the ESX-5 secretion system and its substrate PPE10, in the capsular integrity of pathogenic mycobacteria. These findings open up new roads for research on the mycobacterial capsule and its role in virulence and immune modulation.
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Affiliation(s)
- Louis S Ates
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands
| | - Aniek D van der Woude
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands.,Department of Molecular Microbiology, VU University, Amsterdam, the Netherlands
| | - Jovanka Bestebroer
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands
| | | | - René J P Musters
- Department of Physiology and Cardiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Juan J Garcia-Vallejo
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, the Netherlands
| | - Daisy I Picavet
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam the Netherlands
| | - Robert van de Weerd
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands
| | | | - Coenraad P Kuijl
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands
| | - Nicole N van der Wel
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, Amsterdam the Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands.,Department of Molecular Microbiology, VU University, Amsterdam, the Netherlands
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Singh VK, Berry L, Bernut A, Singh S, Carrère-Kremer S, Viljoen A, Alibaud L, Majlessi L, Brosch R, Chaturvedi V, Geurtsen J, Drancourt M, Kremer L. A unique PE_PGRS protein inhibiting host cell cytosolic defenses and sustaining full virulence of Mycobacterium marinum in multiple hosts. Cell Microbiol 2016; 18:1489-1507. [PMID: 27120981 DOI: 10.1111/cmi.12606] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/22/2016] [Accepted: 04/09/2016] [Indexed: 12/11/2022]
Abstract
Despite intense research, PE_PGRS proteins still represent an intriguing aspect of mycobacterial pathogenesis. These cell surface proteins influence virulence in several pathogenic species, but their diverse and exact functions remain unclear. Herein, we focussed on a PE_PGRS member from Mycobacterium marinum, MMAR_0242, characterized by an extended and unique C-terminal domain. We demonstrate that an M. marinum mutant carrying a transposon insertion in MMAR_0242 is highly impaired in its ability to replicate in macrophages and amoebae, because of its inability to inhibit lysosomal fusion. As a consequence, this mutant failed to survive intracellularly as evidenced by a reduced number of cytosolic actin tail-forming bacteria and by quantitative electron microscopy, which mainly localized MMAR_0242::Tn within membrane-defined vacuoles. Functional complementation studies indicated that the C-terminus, but not the N-terminal PE_PGRS domain, is required for intracellular growth/survival. In line with these findings, disruption of MMAR_0242 resulted in a highly attenuated virulence phenotype in zebrafish embryos, characterized by restricted bacterial loads and a failure to produce granulomas. Furthermore, expression of MMAR_0242 in Mycobacterium smegmatis, a non-pathogenic species naturally deficient in PE_PGRS production, resulted in increased survival in amoebae with enhanced cytotoxic cell death and increased survival in infected mice with splenomegaly. Overall, these results indicate that MMAR_0242 is required for full virulence of M. marinum and sufficient to confer pathogenic properties to M. smegmatis.
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Affiliation(s)
- Vipul K Singh
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS UMR 5235, case 107, Place Eugène Bataillon, 34095, Montpellier Cedex 05, France
| | - Laurence Berry
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS UMR 5235, case 107, Place Eugène Bataillon, 34095, Montpellier Cedex 05, France
| | - Audrey Bernut
- Centre d'étude des Pathogènes et Biotechnologies pour la Santé (CPBS), CNRS FRE 3689, 1919 route de Mende, 34293, Montpellier, France
| | - Shubhra Singh
- Biochemistry Division, CSIR-Central Drug Research Institute, 226031, Lucknow, Uttar Pradesh, India.,IFTM University, Lodhipur Rajput, Delhi Road (NH-24) Moradabad, Uttar Pradesh, 244102, India
| | - Séverine Carrère-Kremer
- INSERM U1058, Université de Montpellier and Department of Bacteriology-Virology, CHU de Montpellier, 34095, Montpellier, France
| | - Albertus Viljoen
- Centre d'étude des Pathogènes et Biotechnologies pour la Santé (CPBS), CNRS FRE 3689, 1919 route de Mende, 34293, Montpellier, France
| | - Laeticia Alibaud
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS UMR 5235, case 107, Place Eugène Bataillon, 34095, Montpellier Cedex 05, France
| | - Laleh Majlessi
- Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, 25 rue du Dr. Roux, 75724, Paris, France
| | - Roland Brosch
- Institut Pasteur, Unité de Pathogénomique Mycobactérienne Intégrée, 25 rue du Dr. Roux, 75724, Paris, France
| | - Vinita Chaturvedi
- Biochemistry Division, CSIR-Central Drug Research Institute, 226031, Lucknow, Uttar Pradesh, India
| | - Jeroen Geurtsen
- Department of Medical Microbiology and Infection Control, VU University Medical Center, 1081 BT, Amsterdam, The Netherlands
| | - Michel Drancourt
- Université Aix-Marseille, URMITE, UMR63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Laurent Kremer
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS UMR 5235, case 107, Place Eugène Bataillon, 34095, Montpellier Cedex 05, France. .,Centre d'étude des Pathogènes et Biotechnologies pour la Santé (CPBS), CNRS FRE 3689, 1919 route de Mende, 34293, Montpellier, France. .,INSERM, CPBS, 1919 route de Mende, Montpellier, France.
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Shah S, Briken V. Modular Organization of the ESX-5 Secretion System in Mycobacterium tuberculosis. Front Cell Infect Microbiol 2016; 6:49. [PMID: 27200304 PMCID: PMC4852179 DOI: 10.3389/fcimb.2016.00049] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/18/2016] [Indexed: 11/30/2022] Open
Abstract
Mycobacteria utilize type VII secretion systems (T7SS) to export many of their important virulence proteins. The T7SS encompasses five homologous secretion systems (ESX-1 to ESX-5). Most pathogenic mycobacterial species, including the human pathogen Mycobacterium tuberculosis, possess all five ESX systems. The ESX-1, -3, and -5 systems are important for virulence of mycobacteria but the molecular mechanisms of their secretion apparatus and the identity and activity of secreted effector proteins are not well characterized. The different ESX systems show similarities in gene composition due to their common phylogenetic origin but recent studies demonstrate mechanistic as well as functional variations between the systems. For example, the ESX-1 system is involved in lysis of the phagosomal membrane and phagosomal escape of the bacteria while the ESX-5 system is required for mycobacterial cell wall stability and host cell lysis. Mechanistically, the ESX-1 substrates show interdependence during secretion while the ESX-5 system may use a duplicated four-gene region (ESX-5a) as an accessory system for transport of a subset of proteins of the ESX-5 secretome. In the present review we will provide an overview of the molecular components of the T7SS and their function with a particular focus on the ESX-5 system.
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Affiliation(s)
- Swati Shah
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, MD, USA
| | - Volker Briken
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, MD, USA
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Newton-Foot M, Warren RM, Sampson SL, van Helden PD, Gey van Pittius NC. The plasmid-mediated evolution of the mycobacterial ESX (Type VII) secretion systems. BMC Evol Biol 2016; 16:62. [PMID: 26979252 PMCID: PMC4791881 DOI: 10.1186/s12862-016-0631-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/06/2016] [Indexed: 11/17/2022] Open
Abstract
Background The genome of Mycobacterium tuberculosis contains five copies of the ESX gene cluster, each encoding a dedicated protein secretion system. These ESX secretion systems have been defined as a novel Type VII secretion machinery, responsible for the secretion of proteins across the characteristic outer mycomembrane of the mycobacteria. Some of these secretion systems are involved in virulence and survival in M. tuberculosis; however they are also present in other non-pathogenic mycobacteria, and have been identified in some non-mycobacterial actinomycetes. Three components of the ESX gene cluster have also been found clustered in some gram positive monoderm organisms and are predicted to have preceded the ESX gene cluster. Results This study used in silico and phylogenetic analyses to describe the evolution of the ESX gene cluster from the WXG-FtsK cluster of monoderm bacteria to the five ESX clusters present in M. tuberculosis and other slow-growing mycobacteria. The ancestral gene cluster, ESX-4, was identified in several nonmycomembrane producing actinobacteria as well as the mycomembrane-containing Corynebacteriales in which the ESX cluster began to evolve and diversify. A novel ESX gene cluster, ESX-4EVOL, was identified in some non-mycobacterial actinomycetes and M. abscessus subsp. bolletii. ESX-4EVOL contains all of the conserved components of the ESX gene cluster and appears to be a precursor of the mycobacterial ESX duplications. Between two and seven ESX gene clusters were identified in each mycobacterial species, with ESX-2 and ESX-5 specifically associated with the slow growers. The order of ESX duplication in the mycobacteria is redefined as ESX-4, ESX-3, ESX-1 and then ESX-2 and ESX-5. Plasmid-encoded precursor ESX gene clusters were identified for each of the genomic ESX-3, -1, -2 and -5 gene clusters, suggesting a novel plasmid-mediated mechanism of ESX duplication and evolution. Conclusions The influence of the various ESX gene clusters on vital biological and virulence-related functions has clearly influenced the diversification and success of the various mycobacterial species, and their evolution from the non-pathogenic fast-growing saprophytic to the slow-growing pathogenic organisms. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0631-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mae Newton-Foot
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/SAMRC Centre for Molecular and Cellular Biology, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa.
| | - Robin Mark Warren
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/SAMRC Centre for Molecular and Cellular Biology, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Samantha Leigh Sampson
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/SAMRC Centre for Molecular and Cellular Biology, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Paul David van Helden
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/SAMRC Centre for Molecular and Cellular Biology, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Nicolaas Claudius Gey van Pittius
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/SAMRC Centre for Molecular and Cellular Biology, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
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Majlessi L, Prados-Rosales R, Casadevall A, Brosch R. Release of mycobacterial antigens. Immunol Rev 2015; 264:25-45. [PMID: 25703550 DOI: 10.1111/imr.12251] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mycobacterium tuberculosis has evolved from a Mycobacterium canettii-like progenitor pool into one of the most successful and widespread human pathogens. The pathogenicity of M. tuberculosis is linked to its ability to secrete/export/release selected mycobacterial proteins, and it is also established that active release of mycobacterial antigens is a prerequisite for strong immune recognition. Recent research has enabled mycobacterial secretion systems and vesicle-based release of mycobacterial antigens to be elucidated, which together with host-related specificities constitute key variables that determine the outcome of infection. Here, we discuss recently discovered, novel aspects on the nature and the regulation of antigen release of the tuberculosis agent with particular emphasis on the biological characterization of mycobacteria-specific ESX/type VII secretion systems and their secreted proteins, belonging to the Esx, PE, and PPE categories. The importance of specific mycobacterial antigen release is probably best exemplified by the striking differences observed between the cellular events during infection with the ESX-1-deficient, attenuated Mycobacterium bovis BCG compared to the virulent M. tuberculosis, which are clearly important for design of more specific diagnostics and more efficient vaccines.
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Affiliation(s)
- Laleh Majlessi
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, Paris, France
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31
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Protection and pathology in TB: learning from the zebrafish model. Semin Immunopathol 2015; 38:261-73. [PMID: 26324465 PMCID: PMC4779130 DOI: 10.1007/s00281-015-0522-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/11/2015] [Indexed: 12/14/2022]
Abstract
Zebrafish has earned its place among animal models of tuberculosis. Its natural pathogen, Mycobacterium marinum, shares major virulence factors with the human pathogen Mycobacterium tuberculosis. In adult zebrafish, which possess recombination-activated adaptive immunity, it can cause acute infection or a chronic progressive disease with containment of mycobacteria in well-structured, caseating granulomas. In addition, a low-dose model that closely mimics human latent infection has recently been developed. These models are used alongside infection of optically transparent zebrafish embryos and larvae that rely on innate immunity and permit non-invasive visualization of the early stages of developing granulomas that are inaccessible in other animal models. By microinjecting mycobacteria intravenously or into different tissues, systemic and localized infections can be induced, each useful for studying particular aspects of early pathogenesis, such as phagocyte recruitment, granuloma expansion and maintenance, vascularization of granulomas, and the phagocyte-mediated dissemination of mycobacteria. This has contributed to new insights into the mycobacteria-driven mechanisms that promote granuloma formation, the double-edged role of inflammation, the mechanisms of macrophage cell death that favor disease progression, and the host-protective role of autophagy. As a result, zebrafish models are now increasingly used to explore strategies for adjunctive therapy of tuberculosis with host-directed drugs.
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32
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A Duplicated ESAT-6 Region of ESX-5 Is Involved in Protein Export and Virulence of Mycobacteria. Infect Immun 2015; 83:4349-61. [PMID: 26303392 DOI: 10.1128/iai.00827-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/19/2015] [Indexed: 11/20/2022] Open
Abstract
The ESX-5 secretion system of Mycobacterium tuberculosis is important for bacterial virulence and for the secretion of the large PE/PPE protein family, whose genes constitute 10% of the M. tuberculosis genome. A four-gene region of the ESX-5 system is duplicated three times in the M. tuberculosis genome, but the functions of these duplicates are unknown. Here we investigated one of these duplicates: the region carrying the esxI, esxJ, ppe15, and pe8 genes (ESX-5a). An ESX-5a deletion mutant in the model system M. marinum background was deficient in the secretion of some members of the PE/PPE family of proteins. Surprisingly, we also identified other proteins that are not members of this family, thus expanding the range of ESX-5 secretion substrates. In addition, we demonstrated that ESX-5a is important for the virulence of M. marinum in the zebrafish model. Furthermore, we showed the role of the M. tuberculosis ESX-5a region in inflammasome activation but not host cell death induction, which is different from the case for the M. tuberculosis ESX-5 system. In conclusion, the ESX-5a region is nonredundant with its ESX-5 paralog and is necessary for secretion of a specific subset of proteins in M. tuberculosis and M. marinum that are important for bacterial virulence of M. marinum. Our findings point to a role for the three ESX-5 duplicate regions in the selection of substrates for secretion via ESX-5, and hence, they provide the basis for a refined model of the molecular mechanism of this type VII secretion system.
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33
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First Demonstration of Antigen Induced Cytokine Expression by CD4-1+ Lymphocytes in a Poikilotherm: Studies in Zebrafish (Danio rerio). PLoS One 2015; 10:e0126378. [PMID: 26083432 PMCID: PMC4470515 DOI: 10.1371/journal.pone.0126378] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 04/01/2015] [Indexed: 01/19/2023] Open
Abstract
Adaptive immunity in homeotherms depends greatly on CD4+ Th cells which release cytokines in response to specific antigen stimulation. Whilst bony fish and poikilothermic tetrapods possess cells that express TcR and CD4-related genes (that exist in two forms in teleost fish; termed CD4-1 and CD4-2), to date there is no unequivocal demonstration that cells equivalent to Th exist. Thus, in this study we determined whether CD4-1+ lymphocytes can express cytokines typical of Th cells following antigen specific stimulation, using the zebrafish (Danio rerio). Initially, we analyzed the CD4 locus in zebrafish and found three CD4 homologues, a CD4-1 molecule and two CD4-2 molecules. The zfCD4-1 and zfCD4-2 transcripts were detected in immune organs and were most highly expressed in lymphocytes. A polyclonal antibody to zfCD4-1 was developed and used with an antibody to ZAP70 and revealed double positive cells by immunohistochemistry, and in the Mycobacterium marinum disease model CD4-1+ cells were apparent surrounding the granulomas typical of the infection. Next a prime-boost experiment, using human gamma globulin as antigen, was performed and revealed for the first time in fish that zfCD4-1+ lymphocytes increase the expression of cytokines and master transcription factors relevant to Th1/Th2-type responses as a consequence of boosting with specific antigen.
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34
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Ates LS, Ummels R, Commandeur S, van der Weerd R, Sparrius M, Weerdenburg E, Alber M, Kalscheuer R, Piersma SR, Abdallah AM, Abd El Ghany M, Abdel-Haleem AM, Pain A, Jiménez CR, Bitter W, Houben EN. Essential Role of the ESX-5 Secretion System in Outer Membrane Permeability of Pathogenic Mycobacteria. PLoS Genet 2015; 11:e1005190. [PMID: 25938982 PMCID: PMC4418733 DOI: 10.1371/journal.pgen.1005190] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 04/02/2015] [Indexed: 12/03/2022] Open
Abstract
Mycobacteria possess different type VII secretion (T7S) systems to secrete proteins across their unusual cell envelope. One of these systems, ESX-5, is only present in slow-growing mycobacteria and responsible for the secretion of multiple substrates. However, the role of ESX-5 substrates in growth and/or virulence is largely unknown. In this study, we show that esx-5 is essential for growth of both Mycobacterium marinum and Mycobacterium bovis. Remarkably, this essentiality can be rescued by increasing the permeability of the outer membrane, either by altering its lipid composition or by the introduction of the heterologous porin MspA. Mutagenesis of the first nucleotide-binding domain of the membrane ATPase EccC5 prevented both ESX-5-dependent secretion and bacterial growth, but did not affect ESX-5 complex assembly. This suggests that the rescuing effect is not due to pores formed by the ESX-5 membrane complex, but caused by ESX-5 activity. Subsequent proteomic analysis to identify crucial ESX-5 substrates confirmed that all detectable PE and PPE proteins in the cell surface and cell envelope fractions were routed through ESX-5. Additionally, saturated transposon-directed insertion-site sequencing (TraDIS) was applied to both wild-type M. marinum cells and cells expressing mspA to identify genes that are not essential anymore in the presence of MspA. This analysis confirmed the importance of esx-5, but we could not identify essential ESX-5 substrates, indicating that multiple of these substrates are together responsible for the essentiality. Finally, examination of phenotypes on defined carbon sources revealed that an esx-5 mutant is strongly impaired in the uptake and utilization of hydrophobic carbon sources. Based on these data, we propose a model in which the ESX-5 system is responsible for the transport of cell envelope proteins that are required for nutrient uptake. These proteins might in this way compensate for the lack of MspA-like porins in slow-growing mycobacteria.
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Affiliation(s)
- Louis S. Ates
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Roy Ummels
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Susanna Commandeur
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Robert van der Weerd
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Marion Sparrius
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Eveline Weerdenburg
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Marina Alber
- Institute for Medical Microbiology and Hospital Hygiene, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Rainer Kalscheuer
- Institute for Medical Microbiology and Hospital Hygiene, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Sander R. Piersma
- Department of Medical Oncology, OncoProteomics Laboratory, VU University Medical Center, Amsterdam, the Netherlands
| | - Abdallah M. Abdallah
- Biological and Environmental Sciences and Engineering (BESE) division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Moataz Abd El Ghany
- Biological and Environmental Sciences and Engineering (BESE) division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Alyaa M. Abdel-Haleem
- Biological and Environmental Sciences and Engineering (BESE) division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Arnab Pain
- Biological and Environmental Sciences and Engineering (BESE) division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Connie R. Jiménez
- Department of Medical Oncology, OncoProteomics Laboratory, VU University Medical Center, Amsterdam, the Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicine & Systems, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Edith N.G. Houben
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicine & Systems, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
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Abstract
Despite efforts to generate new vaccines and antibiotics for tuberculosis, the disease remains a public health problem worldwide. The zebrafish Danio rerio has emerged as a useful model to investigate mycobacterial pathogenesis and treatment. Infection of zebrafish with Mycobacterium marinum, the closest relative of the Mycobacterium tuberculosis complex, recapitulates many aspects of human tuberculosis. The zebrafish model affords optical transparency, abundant genetic tools and in vivo imaging of the progression of infection. Here, we review how the zebrafish–M. marinum system has been deployed to make novel observations about the role of innate immunity, the tuberculous granuloma, and crucial host and bacterial genes. Finally, we assess how these findings relate to human disease and provide a framework for novel strategies to treat tuberculosis.
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Affiliation(s)
- Mark R Cronan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - David M Tobin
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA. Center for Microbial Pathogenesis, Duke University Medical Center, Durham, NC 27710, USA.
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36
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Genome-wide transposon mutagenesis indicates that Mycobacterium marinum customizes its virulence mechanisms for survival and replication in different hosts. Infect Immun 2015; 83:1778-88. [PMID: 25690095 DOI: 10.1128/iai.03050-14] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 02/05/2015] [Indexed: 11/20/2022] Open
Abstract
The interaction of environmental bacteria with unicellular eukaryotes is generally considered a major driving force for the evolution of intracellular pathogens, allowing them to survive and replicate in phagocytic cells of vertebrate hosts. To test this hypothesis on a genome-wide level, we determined for the intracellular pathogen Mycobacterium marinum whether it uses conserved strategies to exploit host cells from both protozoan and vertebrate origin. Using transposon-directed insertion site sequencing (TraDIS), we determined differences in genetic requirements for survival and replication in phagocytic cells of organisms from different kingdoms. In line with the general hypothesis, we identified a number of general virulence mechanisms, including the type VII protein secretion system ESX-1, biosynthesis of polyketide lipids, and utilization of sterols. However, we were also able to show that M. marinum contains an even larger set of host-specific virulence determinants, including proteins involved in the modification of surface glycolipids and, surprisingly, the auxiliary proteins of the ESX-1 system. Several of these factors were in fact counterproductive in other hosts. Therefore, M. marinum contains different sets of virulence factors that are tailored for specific hosts. Our data imply that although amoebae could function as a training ground for intracellular pathogens, they do not fully prepare pathogens for crossing species barriers.
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37
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van Leeuwen LM, van der Sar AM, Bitter W. Animal models of tuberculosis: zebrafish. Cold Spring Harb Perspect Med 2014; 5:a018580. [PMID: 25414379 DOI: 10.1101/cshperspect.a018580] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Over the past decade the zebrafish (Danio rerio) has become an attractive new vertebrate model organism for studying mycobacterial pathogenesis. The combination of medium-throughput screening and real-time in vivo visualization has allowed new ways to dissect host pathogenic interaction in a vertebrate host. Furthermore, genetic screens on the host and bacterial sides have elucidated new mechanisms involved in the initiation of granuloma formation and the importance of a balanced immune response for control of mycobacterial pathogens. This article will highlight the unique features of the zebrafish-Mycobacterium marinum infection model and its added value for tuberculosis research.
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Affiliation(s)
- Lisanne M van Leeuwen
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands Department of Medical Microbiology and Infection control, VU University Medical Center, 1081 BT Amsterdam, The Netherlands
| | - Astrid M van der Sar
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - Wilbert Bitter
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands Department of Molecular Microbiology, VU University, 1081 HV Amsterdam, The Netherlands
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38
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Korotkova N, Freire D, Phan TH, Ummels R, Creekmore CC, Evans TJ, Wilmanns M, Bitter W, Parret AHA, Houben ENG, Korotkov KV. Structure of the Mycobacterium tuberculosis type VII secretion system chaperone EspG5 in complex with PE25-PPE41 dimer. Mol Microbiol 2014; 94:367-82. [PMID: 25155747 DOI: 10.1111/mmi.12770] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2014] [Indexed: 11/29/2022]
Abstract
The growth or virulence of Mycobacterium tuberculosis bacilli depends on homologous type VII secretion systems, ESX-1, ESX-3 and ESX-5, which export a number of protein effectors across membranes to the bacterial surface and environment. PE and PPE proteins represent two large families of highly polymorphic proteins that are secreted by these ESX systems. Recently, it was shown that these proteins require system-specific cytoplasmic chaperones for secretion. Here, we report the crystal structure of M. tuberculosis ESX-5-secreted PE25-PPE41 heterodimer in complex with the cytoplasmic chaperone EspG(5). EspG(5) represents a novel fold that is unrelated to previously characterized secretion chaperones. Functional analysis of the EspG(5) -binding region uncovered a hydrophobic patch on PPE41 that promotes dimer aggregation, and the chaperone effectively abolishes this process. We show that PPE41 contains a characteristic chaperone-binding sequence, the hh motif, which is highly conserved among ESX-1-, ESX-3- and ESX-5-specific PPE proteins. Disrupting the interaction between EspG(5) and three different PPE target proteins by introducing different point mutations generally affected protein secretion. We further demonstrate that the EspG(5) chaperone plays an important role in the ESX secretion mechanism by keeping aggregation-prone PE-PPE proteins in their soluble state.
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Affiliation(s)
- Natalia Korotkova
- Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, KY, 40536, USA; Center for Structural Biology, University of Kentucky, Lexington, KY, 40536, USA
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Rowe HM, Withey JH, Neely MN. Zebrafish as a model for zoonotic aquatic pathogens. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 46:96-107. [PMID: 24607289 PMCID: PMC4096445 DOI: 10.1016/j.dci.2014.02.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/22/2014] [Accepted: 02/22/2014] [Indexed: 06/03/2023]
Abstract
Aquatic habitats harbor a multitude of bacterial species. Many of these bacteria can act as pathogens to aquatic species and/or non-aquatic organisms, including humans, that come into contact with contaminated water sources or colonized aquatic organisms. In many instances, the bacteria are not pathogenic to the aquatic species they colonize and are only considered pathogens when they come into contact with humans. There is a general lack of knowledge about how the environmental lifestyle of these pathogens allows them to persist, replicate and produce the necessary pathogenic mechanisms to successfully transmit to the human host and cause disease. Recently, the zebrafish infectious disease model has emerged as an ideal system for examining aquatic pathogens, both in the aquatic environment and during infection of the human host. This review will focus on how the zebrafish has been used successfully to analyze the pathogenesis of aquatic bacterial pathogens.
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Affiliation(s)
- Hannah M Rowe
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Jeffrey H Withey
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Melody N Neely
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI, USA.
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Grayfer L, Hodgkinson JW, Belosevic M. Antimicrobial responses of teleost phagocytes and innate immune evasion strategies of intracellular bacteria. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 43:223-42. [PMID: 23954721 DOI: 10.1016/j.dci.2013.08.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 08/02/2013] [Accepted: 08/03/2013] [Indexed: 05/22/2023]
Abstract
During infection, macrophage lineage cells eliminate infiltrating pathogens through a battery of antimicrobial responses, where the efficacy of these innate immune responses is pivotal to immunological outcomes. Not surprisingly, many intracellular pathogens have evolved mechanisms to overcome macrophage defenses, using these immune cells as residences and dissemination strategies. With pathogenic infections causing increasing detriments to both aquacultural and wild fish populations, it is imperative to garner greater understanding of fish phagocyte antimicrobial responses and the mechanisms by which aquatic pathogens are able to overcome these teleost macrophage barriers. Insights into the regulation of macrophage immunity of bony fish species will lend to the development of more effective aquacultural prophylaxis as well as broadening our understanding of the evolution of these immune processes. Accordingly, this review focuses on recent advances in the understanding of teleost macrophage antimicrobial responses and the strategies by which intracellular fish pathogens are able to avoid being killed by phagocytes, with a focus on Mycobacterium marinum.
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Affiliation(s)
- Leon Grayfer
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY, USA
| | | | - Miodrag Belosevic
- Department of Biological Sciences, University of Alberta, Edmonton, Canada; School of Public Health, University of Alberta, Edmonton, Canada.
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Chang JH, Desveaux D, Creason AL. The ABCs and 123s of bacterial secretion systems in plant pathogenesis. ANNUAL REVIEW OF PHYTOPATHOLOGY 2014; 52:317-45. [PMID: 24906130 DOI: 10.1146/annurev-phyto-011014-015624] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Bacteria have many export and secretion systems that translocate cargo into and across biological membranes. Seven secretion systems contribute to pathogenicity by translocating proteinaceous cargos that can be released into the extracellular milieu or directly into recipient cells. In this review, we describe these secretion systems and how their complexities and functions reflect differences in the destinations, states, functions, and sizes of the translocated cargos as well as the architecture of the bacterial cell envelope. We examine the secretion systems from the perspective of pathogenic bacteria that proliferate within plant tissues and highlight examples of translocated proteins that contribute to the infection and disease of plant hosts.
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Affiliation(s)
- Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331; ,
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The ESX-5 associated eccB-EccC locus is essential for Mycobacterium tuberculosis viability. PLoS One 2012; 7:e52059. [PMID: 23284869 PMCID: PMC3524121 DOI: 10.1371/journal.pone.0052059] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 11/12/2012] [Indexed: 12/20/2022] Open
Abstract
The recently described ESX-5 secretion system of Mycobacterium tuberculosis is one of the most important modulators of host-pathogen interactions due to its crucial impact on PPE protein secretion, cell wall stability and virulence. Although various components of the ESX-5 secretion machinery have been defined, other ESX-5 core components still remain to be characterized. In this study, we focused on EccB5 and EccC5, a transmembrane protein (EccB5) and a membrane-bound ATPase (EccC5), both predicted to be building blocks of the M. tuberculosis ESX-5 membrane-associated complex. In vitro expression studies demonstrated that EccB5 and EccC5 encoding genes constitute an operon. The expression of this operon is essential for M. tuberculosis, since the deletion of the eccB5-eccC5 genomic segment at the ESX-5 locus is possible only after the integration of a second functional copy of eccB5-eccC5 genes into the M. tuberculosis chromosome. The characterization of two M. tuberculosis conditional mutant strains (MtbPptreccB5 and MtbPptreccC5), in which the eccB5-eccC5 operon or the eccC5 gene, respectively, were expressed under the control of an anhydrotetracycline-repressible promoter, confirmed that the repression of eccB5-eccC5 genes is detrimental for growth of M. tuberculosis both in vitro and in THP-1 human macrophage cell line. Moreover, analysis of the secretome of MtbPptreccB5-eccC5 and MtbPptreccC5 strains revealed that both EccB5 and EccC5 are required for secretion of ESX-5 specific substrates, thus confirming that they are indeed components of the ESX-5 secretion machinery. Taken together these findings demonstrate the importance of an intact and functional ESX-5 system for viability of M. tuberculosis, thus opening new interesting options for alternative antimycobacterial control strategies.
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Sayes F, Sun L, Di Luca M, Simeone R, Degaiffier N, Fiette L, Esin S, Brosch R, Bottai D, Leclerc C, Majlessi L. Strong immunogenicity and cross-reactivity of Mycobacterium tuberculosis ESX-5 type VII secretion: encoded PE-PPE proteins predicts vaccine potential. Cell Host Microbe 2012; 11:352-63. [PMID: 22520463 DOI: 10.1016/j.chom.2012.03.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/23/2012] [Accepted: 03/22/2012] [Indexed: 10/28/2022]
Abstract
The genome of Mycobacterium tuberculosis (Mtb) encodes five type VII secretion systems, ESX-1 to ESX-5, most of which are associated with genes encoding PE/PPE proteins, named after their N-terminal Pro-Glu (PE) or Pro-Pro-Glu (PPE) motifs. Here, we describe the strong T cell immunogenicity of the ESX-5-encoded PE/PPE proteins, which share a large panel of cross-reactive CD4(+) epitopes with substantial numbers of their ESX-5-nonassociated PE/PPE homologs. The immunogenicity of these numerous PE/PPE proteins is dependent on their export by a functional EccD(5), the predicted transmembrane channel of the ESX-5 secretion apparatus. The Mtb Δppe25-pe19 mutant deleted for all ESX-5-associated pe and ppe genes, although highly attenuated in immunocompetent mice, remains able to induce immunity against the ESX-5-associated PE/PPE virulence factors, via cross-reactivity with their numerous homologs, and against the ESX-1 virulence factors ESAT-6/CFP-10. The Δppe25-pe19 strain is strongly protective against Mtb infection in mice and represents a potential antituberculosis vaccine candidate.
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Affiliation(s)
- Fadel Sayes
- Unité de Régulation Immunitaire et Vaccinologie, Institut Pasteur, Paris, France
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Li YJ, Hu B. Establishment of Multi-Site Infection Model in Zebrafish Larvae for Studying Staphylococcus aureus Infectious Disease. J Genet Genomics 2012; 39:521-34. [DOI: 10.1016/j.jgg.2012.07.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 06/26/2012] [Accepted: 07/16/2012] [Indexed: 11/30/2022]
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Houben ENG, Bestebroer J, Ummels R, Wilson L, Piersma SR, Jiménez CR, Ottenhoff THM, Luirink J, Bitter W. Composition of the type VII secretion system membrane complex. Mol Microbiol 2012; 86:472-84. [DOI: 10.1111/j.1365-2958.2012.08206.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2012] [Indexed: 01/04/2023]
Affiliation(s)
| | - Jovanka Bestebroer
- Department of Medical Microbiology and Infection Control; VU University Medical Center; Amsterdam; The Netherlands
| | - Roy Ummels
- Department of Medical Microbiology and Infection Control; VU University Medical Center; Amsterdam; The Netherlands
| | - Louis Wilson
- Department of Infectious Diseases; Leiden University Medical Center; Leiden; The Netherlands
| | - Sander R. Piersma
- Department of Medical Oncology; OncoProteomics Laboratory; VU University Medical Center; Amsterdam; The Netherlands
| | - Connie R. Jiménez
- Department of Medical Oncology; OncoProteomics Laboratory; VU University Medical Center; Amsterdam; The Netherlands
| | - Tom H. M. Ottenhoff
- Department of Infectious Diseases; Leiden University Medical Center; Leiden; The Netherlands
| | - Joen Luirink
- Department of Molecular Microbiology; Institute of Molecular Cell Biology; VU University Amsterdam; Amsterdam; The Netherlands
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Stoop EJM, Bitter W, van der Sar AM. Tubercle bacilli rely on a type VII army for pathogenicity. Trends Microbiol 2012; 20:477-84. [PMID: 22858229 DOI: 10.1016/j.tim.2012.07.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 06/26/2012] [Accepted: 07/03/2012] [Indexed: 12/22/2022]
Abstract
Mycobacteria, such as the major human pathogen Mycobacterium tuberculosis, have a highly unusual and characteristic diderm cell envelope that protects them against harmful conditions. Protein secretion across this hydrophobic barrier requires specialized secretion systems. Recently, a type VII secretion (T7S) pathway has been identified that fulfills this function. Pathogenic mycobacteria have up to five different T7S systems, some of which play a crucial role in virulence. The interactions between secreted substrates and host molecules are only starting to become clear and will help in furthering our understanding of the persistence of these enigmatic pathogens. In this review, we discuss current knowledge on the role of T7S systems in mycobacterial virulence.
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Affiliation(s)
- Esther J M Stoop
- Department of Medical Microbiology and Infection control, VU University Medical Center, van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
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Bottai D, Di Luca M, Majlessi L, Frigui W, Simeone R, Sayes F, Bitter W, Brennan MJ, Leclerc C, Batoni G, Campa M, Brosch R, Esin S. Disruption of the ESX-5 system of Mycobacterium tuberculosis causes loss of PPE protein secretion, reduction of cell wall integrity and strong attenuation. Mol Microbiol 2012; 83:1195-209. [DOI: 10.1111/j.1365-2958.2012.08001.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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van der Woude AD, Luirink J, Bitter W. Getting across the cell envelope: mycobacterial protein secretion. Curr Top Microbiol Immunol 2012; 374:109-34. [PMID: 23239236 DOI: 10.1007/82_2012_298] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Protein secretion is an essential determinant of mycobacterial virulence. Mycobacterium tuberculosis has a unique cell envelope consisting of two lipid bilayers, which requires dedicated protein secretion pathways. The conserved general Sec and Tat translocation systems are responsible for protein transport across the inner membrane and are both essential. Additionally, the accessory Sec pathway specifically contributes to virulence. How transport of Sec/Tat substrates across the outer membrane is accomplished is currently an enigma. In addition to these pathways, M. tuberculosis also developed specialized secretion systems for protein transport across both membranes, the type VII or ESX secretion systems. Here, we discuss our current knowledge about the mechanisms and substrates of these different protein translocation systems and their role in mycobacterial physiology and virulence.
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Affiliation(s)
- Aniek D van der Woude
- Department of Molecular Microbiology, Institute of Molecular Cell Biology, VU University, Amsterdam, The Netherlands
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