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Daher W, Le Moigne V, Tasrini Y, Parmar S, Sexton DL, Aguilera-Correa JJ, Berdal V, Tocheva EI, Herrmann JL, Kremer L. Deletion of ESX-3 and ESX-4 secretion systems in Mycobacterium abscessus results in highly impaired pathogenicity. Commun Biol 2025; 8:166. [PMID: 39900631 PMCID: PMC11791044 DOI: 10.1038/s42003-025-07572-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2024] [Accepted: 01/17/2025] [Indexed: 02/05/2025] Open
Abstract
Type VII secretion systems participate in protein export, virulence, conjugation, and metabolic regulation. Five subtypes (ESX-1 to ESX-5) exist, each with specific roles and well-characterized secretion profiles in various mycobacterial species. Mycobacterium abscessus, encodes only ESX-3 and ESX-4. Here, single and double M. abscessus mutants lacking the main ATPases EccC3 and EccC4 were used to define ESX-3 and ESX-4 contributions to substrate secretion and virulence. Our results demonstrate that EsxG/H secretion depends entirely on ESX-3, whereas both ESX-3 and ESX-4 secrete EsxU/T. Furthermore, two newly identified PE/PPE substrates (MAB_0046/MAB_0047) require ESX-3 for secretion. Functional complementation restored secretion and revealed subpolar localization of these systems. Macrophage infections showed that ESX-3 and ESX-4 contribute to bacterial internalization, phagosomal escape, and intracellular survival. In mice, infections with eccC3- and/or eccC4-deletion mutants resulted in complete survival and reduced bacterial loads in the lungs. These findings demonstrate that both ESX systems drive M. abscessus pathogenicity.
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Affiliation(s)
- Wassim Daher
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293, Montpellier, France.
- INSERM, IRIM, 34293, Montpellier, France.
| | - Vincent Le Moigne
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France
| | - Yara Tasrini
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293, Montpellier, France
| | - Shweta Parmar
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Danielle L Sexton
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - John Jairo Aguilera-Correa
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293, Montpellier, France
| | - Valentin Berdal
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293, Montpellier, France
| | - Elitza I Tocheva
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293, Montpellier, France.
- INSERM, IRIM, 34293, Montpellier, France.
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An Y, Ni R, Zhuang L, Yang L, Ye Z, Li L, Parkkila S, Aspatwar A, Gong W. Tuberculosis vaccines and therapeutic drug: challenges and future directions. MOLECULAR BIOMEDICINE 2025; 6:4. [PMID: 39841361 PMCID: PMC11754781 DOI: 10.1186/s43556-024-00243-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2024] [Revised: 12/06/2024] [Accepted: 12/24/2024] [Indexed: 01/23/2025] Open
Abstract
Tuberculosis (TB) remains a prominent global health challenge, with the World Health Organization documenting over 1 million annual fatalities. Despite the deployment of the Bacille Calmette-Guérin (BCG) vaccine and available therapeutic agents, the escalation of drug-resistant Mycobacterium tuberculosis strains underscores the pressing need for more efficacious vaccines and treatments. This review meticulously maps out the contemporary landscape of TB vaccine development, with a focus on antigen identification, clinical trial progress, and the obstacles and future trajectories in vaccine research. We spotlight innovative approaches, such as multi-antigen vaccines and mRNA technology platforms. Furthermore, the review delves into current TB therapeutics, particularly for multidrug-resistant tuberculosis (MDR-TB), exploring promising agents like bedaquiline (BDQ) and delamanid (DLM), as well as the potential of host-directed therapies. The hurdles in TB vaccine and therapeutic development encompass overcoming antigen diversity, enhancing vaccine effectiveness across diverse populations, and advancing novel vaccine platforms. Future initiatives emphasize combinatorial strategies, the development of anti-TB compounds targeting novel pathways, and personalized medicine for TB treatment and prevention. Despite notable advances, persistent challenges such as diagnostic failures and protracted treatment regimens continue to impede progress. This work aims to steer future research endeavors toward groundbreaking TB vaccines and therapeutic agents, providing crucial insights for enhancing TB prevention and treatment strategies.
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Affiliation(s)
- Yajing An
- Beijing Key Laboratory of New Techniques of Tuberculosis Diagnosis and Treatment, Senior Department of Tuberculosis, The Eighth Medical Center of PLA General Hospital, 17#Heishanhu Road, Haidian District, Beijing, 100091, China
- Graduate School, Hebei North University, Zhangjiakou, 075000, Hebei, China
| | - Ruizi Ni
- Graduate School, Hebei North University, Zhangjiakou, 075000, Hebei, China
| | - Li Zhuang
- Graduate School, Hebei North University, Zhangjiakou, 075000, Hebei, China
| | - Ling Yang
- Graduate School, Hebei North University, Zhangjiakou, 075000, Hebei, China
| | - Zhaoyang Ye
- Graduate School, Hebei North University, Zhangjiakou, 075000, Hebei, China
| | - Linsheng Li
- Graduate School, Hebei North University, Zhangjiakou, 075000, Hebei, China
| | - Seppo Parkkila
- Faculty of Medicine and Health Technology, Tampere University, 33014, Tampere, Finland
- Department of Clinical Chemistry, Fimlab Laboratories PLC, Tampere, Finland
| | - Ashok Aspatwar
- Faculty of Medicine and Health Technology, Tampere University, 33014, Tampere, Finland.
| | - Wenping Gong
- Beijing Key Laboratory of New Techniques of Tuberculosis Diagnosis and Treatment, Senior Department of Tuberculosis, The Eighth Medical Center of PLA General Hospital, 17#Heishanhu Road, Haidian District, Beijing, 100091, China.
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Olmo-Fontánez AM, Allué-Guardia A, Garcia-Vilanova A, Glenn J, Wang SH, Merritt RE, Schlesinger LS, Turner J, Wang Y, Torrelles JB. Impact of the elderly lung mucosa on Mycobacterium tuberculosis transcriptional adaptation during infection of alveolar epithelial cells. Microbiol Spectr 2024; 12:e0179024. [PMID: 39513699 PMCID: PMC11619525 DOI: 10.1128/spectrum.01790-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2024] [Accepted: 10/10/2024] [Indexed: 11/15/2024] Open
Abstract
Tuberculosis is one of the leading causes of death due to a single infectious agent. Upon infection, Mycobacterium tuberculosis (M.tb) is deposited in the alveoli and encounters the lung mucosa or alveolar lining fluid (ALF). We previously showed that, as we age, ALF presents a higher degree of oxidation and inflammatory mediators, which favors M.tb replication in human macrophages and alveolar epithelial cells (ATs). Here, we define the transcriptional profile of M.tb when exposed to healthy ALF from adult (A-ALF) or elderly (E-ALF) humans before and during infection of ATs. Prior to infection, M.tb exposure to E-ALF upregulated genes essential for bacterial host adaptation directly involved in M.tb pathogenesis. During infection of ATs, E-ALF exposed M.tb further upregulated genes involved in its ability to escape into the AT cytosol bypassing critical host defense mechanisms, as well as genes associated with defense against oxidative stress. These findings demonstrate how alterations in human ALF during the aging process can impact the metabolic status of M.tb, potentially enabling a greater adaptation and survival within host cells. Importantly, we present the first transcriptomic analysis on the impact of the elderly lung mucosa on M.tb pathogenesis during intracellular replication in ATs.IMPORTANCETuberculosis is one of the leading causes of death due to a single infectious agent. Upon infection, Mycobacterium tuberculosis (M.tb) is deposited in the alveoli and comes in contact with the alveolar lining fluid (ALF). We previously showed that elderly ALF favors M.tb replication in human macrophages and alveolar epithelial cells (ATs). Here we define the transcriptional profile of when exposed to healthy ALF from adult (A-ALF) or elderly (E-ALF) humans before and during infection of ATs. Prior to infection, exposure to E-ALF upregulates genes essential for bacterial host adaptation and pathogenesis. During infection of ATs, E-ALF further upregulates M.tb genes involved in its ability to escape into the AT cytosol, as well as genes for defense against oxidative stress. These findings demonstrate how alterations in human ALF during the aging process can impact the metabolic status of M.tb, potentially enabling a greater adaptation and survival within host cells.
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Affiliation(s)
- Angélica M. Olmo-Fontánez
- Population Health and Host-Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, Texas, USA
- Integrated Biomedical Sciences Program, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Anna Allué-Guardia
- Population Health and Host-Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, Texas, USA
- International Center for the Advancement of Research & Education (I • CARE), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Andreu Garcia-Vilanova
- Population Health and Host-Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Jeremy Glenn
- Population Health and Host-Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Shu-Hua Wang
- Department of Internal Medicine, Infectious Disease Division, The Ohio State University, Columbus, Ohio, USA
| | - Robert E. Merritt
- Department of Surgery, The Ohio State University, Columbus, Ohio, USA
| | - Larry S. Schlesinger
- Population Health and Host-Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, Texas, USA
- International Center for the Advancement of Research & Education (I • CARE), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Joanne Turner
- Population Health and Host-Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, Texas, USA
- International Center for the Advancement of Research & Education (I • CARE), Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Yufeng Wang
- Department of Molecular Microbiology and Immunology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, Texas, USA
| | - Jordi B. Torrelles
- Population Health and Host-Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, Texas, USA
- International Center for the Advancement of Research & Education (I • CARE), Texas Biomedical Research Institute, San Antonio, Texas, USA
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Malik AA, Shariq M, Sheikh JA, Jaiswal U, Fayaz H, Shrivastava G, Ehtesham NZ, Hasnain SE. Mechanisms of immune evasion by Mycobacterium tuberculosis: the impact of T7SS and cell wall lipids on host defenses. Crit Rev Biochem Mol Biol 2024; 59:310-336. [PMID: 39378051 DOI: 10.1080/10409238.2024.2411264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Revised: 09/21/2024] [Accepted: 09/27/2024] [Indexed: 11/14/2024]
Abstract
Mycobacterium tuberculosis (M. tb) is one of the most successful human pathogens, causing a severe and widespread infectious disease. The frequent emergence of multidrug-resistant (MDR) strains has exacerbated this public health crisis, particularly in underdeveloped regions. M. tb employs a sophisticated array of virulence factors to subvert host immune responses, both innate and adaptive. It utilizes the early secretory antigenic target (ESAT6) secretion system 1 (ESX-1) type VII secretion system (T7SS) and cell wall lipids to disrupt phagosomal integrity, inhibiting phagosome maturation, and fusion with lysosomes. Although host cells activate mechanisms such as ubiquitin (Ub), Ub-ligase, and cyclic GMP-AMP synthase-stimulator of interferon genes 1 (CGAS-STING1)-mediated autophagy to inhibit M. tb survival within macrophages, the pathogen counteracts these defenses with its own virulence factors, thereby inhibiting autophagy and dampening host-directed responses. T7SSs are critical for transporting proteins across the complex mycobacterial cell envelope, performing essential functions, including metabolite uptake, immune evasion, and conjugation. T7SS substrates fall into two main families: ESAT-6 system proteins, which are found in both Firmicutes and Actinobacteria, and proline-glutamic acid (PE) and proline-proline-glutamic acid (PPE) proteins, which are unique to mycobacteria. Recent studies have highlighted the significance of T7SSs in mycobacterial growth, virulence, and pathogenesis. Understanding the mechanisms governing T7SSs could pave the way for novel therapeutic strategies to combat mycobacterial diseases, including tuberculosis (TB).
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Affiliation(s)
- Asrar Ahmad Malik
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida, Uttar Pradesh, India
| | - Mohd Shariq
- GITAM School of Science, GITAM University, Rudraram, Telangana, India
| | - Javaid Ahmad Sheikh
- Department of Biotechnology, School of Chemical and Life Sciences, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Udyeshita Jaiswal
- Department of Biotechnology, School of Chemical and Life Sciences, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Haleema Fayaz
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida, Uttar Pradesh, India
| | - Gauri Shrivastava
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida, Uttar Pradesh, India
| | - Nasreen Z Ehtesham
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida, Uttar Pradesh, India
| | - Seyed E Hasnain
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida, Uttar Pradesh, India
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi (IIT-D), Hauz Khas, New Delhi, India
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Priyanka, Sharma S, Sharma M. Role of PE/PPE proteins of Mycobacterium tuberculosis in triad of host mitochondria, oxidative stress and cell death. Microb Pathog 2024; 193:106757. [PMID: 38908454 DOI: 10.1016/j.micpath.2024.106757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 06/12/2024] [Accepted: 06/18/2024] [Indexed: 06/24/2024]
Abstract
The PE and PPE family proteins of Mycobacterium tuberculosis (Mtb) is exclusively found in pathogenic Mycobacterium species, comprising approximately 8-10 % of the Mtb genome. These emerging virulent factors have been observed to play pivotal roles in Mtb pathogenesis and immune evasion through various strategies. These immunogenic proteins are known to modulate the host immune response and cell-death pathways by targeting the powerhouse of the cell, the mitochondria to support Mtb survival. In this article, we are focused on how PE/PPE family proteins target host mitochondria to induce mitochondrial perturbations, modulate the levels of cellular ROS (Reactive oxygen species) and control cell death pathways. We observed that the time of expression of these proteins at different stages of infection is crucial for elucidating their impact on the cell death pathways and eventually on the outcome of infection. This article focuses on understanding the contributions of the PE/PPE proteins by unravelling the triad of host mitochondria, oxidative stress and cell death pathways that facilitate the Mtb persistence. Understanding the role of these proteins in host cellular pathways and the intricate mechanisms paves the way for the development of novel therapeutic strategies to combat TB infections.
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Affiliation(s)
- Priyanka
- DSKC BioDiscovery Laboratory, Miranda House, and Department of Zoology, University of Delhi, Delhi, 110007, India.
| | - Sadhna Sharma
- DSKC BioDiscovery Laboratory, Miranda House, and Department of Zoology, University of Delhi, Delhi, 110007, India.
| | - Monika Sharma
- DSKC BioDiscovery Laboratory, Miranda House, and Department of Zoology, University of Delhi, Delhi, 110007, India.
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6
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Garrett SR, Higginson AB, Palmer T. Multiple variants of the type VII secretion system in Gram-positive bacteria. MICROLIFE 2024; 5:uqae013. [PMID: 38957458 PMCID: PMC11217815 DOI: 10.1093/femsml/uqae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/08/2024] [Accepted: 06/04/2024] [Indexed: 07/04/2024]
Abstract
Type VII secretion systems (T7SS) are found in bacteria across the Bacillota and Actinomycetota phyla and have been well described in Staphylococcus aureus, Bacillus subtilis, and pathogenic mycobacteria. The T7SS from Actinomycetota and Bacillota share two common components, a membrane-bound EccC/EssC ATPase and EsxA, a small helical hairpin protein of the WXG100 family. However, they also have additional phylum-specific components, and as a result they are termed the T7SSa (Actinomycetota) and T7SSb (Bacillota), respectively. Here, we identify additional organizations of the T7SS across these two phyla and describe eight additional T7SS subtypes, which we have named T7SSc-T7SSj. T7SSd is found exclusively in Actinomycetota including the Olselnella and Bifodobacterium genus, whereas the other seven are found only in Bacillota. All of the novel subtypes contain the canonical ATPase (TsxC) and the WXG100-family protein (TsxA). Most of them also contain a small ubiquitin-related protein, TsxB, related to the T7SSb EsaB/YukD component. Protein kinases, phosphatases, and forkhead-associated (FHA) proteins are often encoded in the novel T7SS gene clusters. Candidate substrates of these novel T7SS subtypes include LXG-domain and RHS proteins. Predicted substrates are frequently encoded alongside genes for additional small WXG100-related proteins that we speculate serve as cosecretion partners. Collectively our findings reveal unexpected diversity in the T7SS in Gram-positive bacteria.
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Affiliation(s)
- Stephen R Garrett
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Andrew B Higginson
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Tracy Palmer
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
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Yang Y, Chen YZ, Xia T. Optimizing antigen selection for the development of tuberculosis vaccines. CELL INSIGHT 2024; 3:100163. [PMID: 38572176 PMCID: PMC10987857 DOI: 10.1016/j.cellin.2024.100163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 04/05/2024]
Abstract
Tuberculosis (TB) remains a prevalent global infectious disease caused by genetically closely related tubercle bacilli in Mycobacterium tuberculosis complex (MTBC). For a century, the Bacillus Calmette-Guérin (BCG) vaccine has been the primary preventive measure against TB. While it effectively protects against extrapulmonary forms of pediatric TB, it lacks consistent efficacy in providing protection against pulmonary TB in adults. Consequently, the exploration and development of novel TB vaccines, capable of providing broad protection to populations, have consistently constituted a prominent area of interest in medical research. This article presents a concise overview of the novel TB vaccines currently undergoing clinical trials, discussing their classification, protective efficacy, immunogenicity, advantages, and limitations. In vaccine development, the careful selection of antigens that can induce strong and diverse specific immune responses is essential. Therefore, we have summarized the molecular characteristics, biological function, immunogenicity, and relevant studies associated with the chosen antigens for TB vaccines. These insights gained from vaccines and immunogenic proteins will inform the development of novel mycobacterial vaccines, particularly mRNA vaccines, for effective TB control.
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Affiliation(s)
- Yang Yang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
| | - Yi-Zhen Chen
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
| | - Tian Xia
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, 730046, China
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Nicholson KR, Cronin RM, Prest RJ, Menon AR, Yang Y, Jennisch MK, Champion MM, Tobin DM, Champion PA. The antagonistic transcription factors, EspM and EspN, regulate the ESX-1 secretion system in M. marinum. mBio 2024; 15:e0335723. [PMID: 38445877 PMCID: PMC11005418 DOI: 10.1128/mbio.03357-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 02/13/2024] [Indexed: 03/07/2024] Open
Abstract
Bacterial pathogens use protein secretion systems to transport virulence factors and regulate gene expression. Among pathogenic mycobacteria, including Mycobacterium tuberculosis and Mycobacterium marinum, the ESAT-6 system 1 (ESX-1) secretion is crucial for host interaction. Secretion of protein substrates by the ESX-1 secretion system disrupts phagosomes, allowing mycobacteria cytoplasmic access during macrophage infections. Deletion or mutation of the ESX-1 system attenuates mycobacterial pathogens. Pathogenic mycobacteria respond to the presence or absence of the ESX-1 system in the cytoplasmic membrane by altering transcription. Under laboratory conditions, the EspM repressor and WhiB6 activator control transcription of specific ESX-1-responsive genes, including the ESX-1 substrate genes. However, deleting the espM or whiB6 gene does not phenocopy the deletion of the ESX-1 substrate genes during macrophage infection by M. marinum. In this study, we identified EspN, a critical transcription factor whose activity is masked by the EspM repressor under laboratory conditions. In the absence of EspM, EspN activates transcription of whiB6 and ESX-1 genes during both laboratory growth and macrophage infection. EspN is also independently required for M. marinum growth within and cytolysis of macrophages, similar to the ESX-1 genes, and for disease burden in a zebrafish larval model of infection. These findings suggest that EspN and EspM coordinate to counterbalance the regulation of the ESX-1 system and support mycobacterial pathogenesis.IMPORTANCEPathogenic mycobacteria, which are responsible for tuberculosis and other long-term diseases, use the ESX-1 system to transport proteins that control the host response to infection and promote bacterial survival. In this study, we identify an undescribed transcription factor that controls the expression of ESX-1 genes and is required for both macrophage and animal infection. However, this transcription factor is not the primary regulator of ESX-1 genes under standard laboratory conditions. These findings identify a critical transcription factor that likely controls expression of a major virulence pathway during infection, but whose effect is not detectable with standard laboratory strains and growth conditions.
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Affiliation(s)
- Kathleen R. Nicholson
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Rachel M. Cronin
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Rebecca J. Prest
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Aruna R. Menon
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Yuwei Yang
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Madeleine K. Jennisch
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Matthew M. Champion
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - David M. Tobin
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Immunology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Patricia A. Champion
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
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9
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Wang S, Fang R, Wang H, Li X, Xing J, Li Z, Song N. The role of transcriptional regulators in metal ion homeostasis of Mycobacterium tuberculosis. Front Cell Infect Microbiol 2024; 14:1360880. [PMID: 38529472 PMCID: PMC10961391 DOI: 10.3389/fcimb.2024.1360880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 02/27/2024] [Indexed: 03/27/2024] Open
Abstract
Metal ions are essential trace elements for all living organisms and play critical catalytic, structural, and allosteric roles in many enzymes and transcription factors. Mycobacterium tuberculosis (MTB), as an intracellular pathogen, is usually found in host macrophages, where the bacterium can survive and replicate. One of the reasons why Tuberculosis (TB) is so difficult to eradicate is the continuous adaptation of its pathogen. It is capable of adapting to a wide range of harsh environmental stresses, including metal ion toxicity in the host macrophages. Altering the concentration of metal ions is the common host strategy to limit MTB replication and persistence. This review mainly focuses on transcriptional regulatory proteins in MTB that are involved in the regulation of metal ions such as iron, copper and zinc. The aim is to offer novel insights and strategies for screening targets for TB treatment, as well as for the development and design of new therapeutic interventions.
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Affiliation(s)
- Shuxian Wang
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Ren Fang
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Hui Wang
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Xiaotian Li
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Jiayin Xing
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
| | - Zhaoli Li
- Drug Innovation Research Center, SAFE Pharmaceutical Technology Co. Ltd., Beijing, China
| | - Ningning Song
- Key Laboratory of Respiratory Tract Pathogens and Drug Therapy, School of Life Science and Technology, Shandong Second Medical University, Weifang, China
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Orgeur M, Sous C, Madacki J, Brosch R. Evolution and emergence of Mycobacterium tuberculosis. FEMS Microbiol Rev 2024; 48:fuae006. [PMID: 38365982 PMCID: PMC10906988 DOI: 10.1093/femsre/fuae006] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/12/2024] [Accepted: 02/13/2024] [Indexed: 02/18/2024] Open
Abstract
Tuberculosis (TB) remains one of the deadliest infectious diseases in human history, prevailing even in the 21st century. The causative agents of TB are represented by a group of closely related bacteria belonging to the Mycobacterium tuberculosis complex (MTBC), which can be subdivided into several lineages of human- and animal-adapted strains, thought to have shared a last common ancestor emerged by clonal expansion from a pool of recombinogenic Mycobacterium canettii-like tubercle bacilli. A better understanding of how MTBC populations evolved from less virulent mycobacteria may allow for discovering improved TB control strategies and future epidemiologic trends. In this review, we highlight new insights into the evolution of mycobacteria at the genus level, describing different milestones in the evolution of mycobacteria, with a focus on the genomic events that have likely enabled the emergence and the dominance of the MTBC. We also review the recent literature describing the various MTBC lineages and highlight their particularities and differences with a focus on host preferences and geographic distribution. Finally, we discuss on putative mechanisms driving the evolution of tubercle bacilli and mycobacteria in general, by taking the mycobacteria-specific distributive conjugal transfer as an example.
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Affiliation(s)
- Mickael Orgeur
- Institut Pasteur, Université Paris Cité, CNRS UMR 6047, Unit for Integrated Mycobacterial Pathogenomics, 75015 Paris, France
| | - Camille Sous
- Institut Pasteur, Université Paris Cité, CNRS UMR 6047, Unit for Integrated Mycobacterial Pathogenomics, 75015 Paris, France
| | - Jan Madacki
- Institut Pasteur, Université Paris Cité, CNRS UMR 6047, Unit for Integrated Mycobacterial Pathogenomics, 75015 Paris, France
- Institut Pasteur, Université Paris Cité, CNRS UMR 2000, Unit for Human Evolutionary Genetics, 75015 Paris, France
| | - Roland Brosch
- Institut Pasteur, Université Paris Cité, CNRS UMR 6047, Unit for Integrated Mycobacterial Pathogenomics, 75015 Paris, France
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Granados-Tristán AL, Hernández-Luna CE, González-Escalante LA, Camacho-Moll ME, Silva-Ramírez B, Bermúdez de León M, Peñuelas-Urquides K. ESX-3 secretion system in Mycobacterium: An overview. Biochimie 2024; 216:46-55. [PMID: 37879428 DOI: 10.1016/j.biochi.2023.10.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 09/26/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023]
Abstract
Mycobacteria are microorganisms distributed in the environment worldwide, and some of them, such as Mycobacterium tuberculosis or M. leprae, are pathogenic. The hydrophobic mycobacterial cell envelope has low permeation and bacteria need to export products across their structure. Mycobacteria possess specialized protein secretion systems, such as the Early Secretory Antigenic Target 6 secretion (ESX) system. Five ESX loci have been described in M. tuberculosis, called ESX-1 to ESX-5. The ESX-3 secretion system has been associated with mycobacterial metabolism and growth. The locus of this system is highly conserved across mycobacterial species. Metallo-proteins regulate negative ESX-3 transcription in high conditions of iron and zinc. Moreover, this secretion system is part of an antioxidant regulatory pathway linked to Zinc. EccA3, EccB3, EccC3, EccD3, and EccE3 are components of the ESX-3 secretion machinery, whereas EsxG-EsxH, PE5-PPE4, and PE15-PPE20 are proteins secreted by this system. In addition, EspG3 and MycP3 are complementary proteins involved in transport and proteolysis respectively. This system is associated to mycobacterial virulence by releasing the bacteria from the phagosome and inhibiting endomembrane damage response. Furthermore, components of this system inhibit the host immune response by reducing the recognition of M. tuberculosis-infected cells. The components of the ESX-3 secretion system play a role in drug resistance and cell wall integrity. Moreover, the expression data of this system indicated that external and internal factors affect ESX-3 locus expression. This review provides an overview of new findings on the ESX-3 secretion system, its regulation, expression, and functions.
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Affiliation(s)
- Ana Laura Granados-Tristán
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico; Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, San Nicolás de los Garza, 66455, Nuevo León, Mexico.
| | - Carlos Eduardo Hernández-Luna
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, San Nicolás de los Garza, 66455, Nuevo León, Mexico.
| | - Laura Adiene González-Escalante
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
| | - María Elena Camacho-Moll
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
| | - Beatriz Silva-Ramírez
- Departamento de Inmunogenética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
| | - Mario Bermúdez de León
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
| | - Katia Peñuelas-Urquides
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, 64720, Nuevo León, Mexico.
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12
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Anand PK, Kaur G, Saini V, Kaur J, Kaur J. N-terminal PPE domain plays an integral role in extracellular transportation and stability of the immunomodulatory Rv3539 protein of the Mycobacterium tuberculosis. Biochimie 2023; 213:30-40. [PMID: 37156406 DOI: 10.1016/j.biochi.2023.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 03/31/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023]
Abstract
Multigene PE/PPE family is exclusively present in mycobacterium species. Only few selected genes of this family have been characterized till date. Rv3539 was annotated as PPE63 with conserved PPE domain at N-terminal and PE-PPE at C-terminal. An α/β hydrolase structural fold, characteristic of lipase/esterase, was present in the PE-PPE domain. To assign the biochemical function to Rv3539, the corresponding gene was cloned in pET-32a (+) as full-length, PPE, and PE-PPE domains individually, followed by expression in E. Coli C41 (DE3). All three proteins demonstrated esterase activity. However, the enzyme activity in the N-terminal PPE domain was very low. The enzyme activity of Rv3539 and PE-PPE proteins was approximately same with the pNP-C4 as optimum substrate at 40 °C and pH 8.0. The loss of enzyme activity after mutating the predicted catalytic triad (Ser296Ala, Asp369Ala, and His395Ala) found only in the PE-PPE domain, confirmed the candidature of the bioinformatically predicted active site residue. The optimal activity and thermostability of the Rv3539 protein was altered by removing the PPE domain. CD-spectroscopy analysis confirmed the role of PPE domain to the thermostability of Rv3539 by maintaining the structural integrity at higher temperatures. The presence of the N-terminal PPE domain directed the Rv3539 protein to the cell membrane/wall and the extracellular compartment. The Rv3539 protein could generate humoral response in TB patients. Therefore, results demonstrated that Rv3539 demonstrated esterase activity. PE-PPE domain of Rv3539 is functionally automated, however, N-terminus domain played a role in protein stabilization and its transportation. Both domains participated in immunomodulation.
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Affiliation(s)
- Pradeep Kumar Anand
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India.
| | - Gagandeep Kaur
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India.
| | - Varinder Saini
- Department of Pulmonary Medicine, Government Medical College and Hospital, Chandigarh, India.
| | - Jasbinder Kaur
- Department of Biochemistry, Government Medical College and Hospital, Chandigarh, India.
| | - Jagdeep Kaur
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India.
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13
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Anand PK, Saini V, Kaur J, Kumar A, Kaur J. Cell wall and immune modulation by Rv1800 (PPE28) helps M. smegmatis to evade intracellular killing. Int J Biol Macromol 2023; 247:125837. [PMID: 37455004 DOI: 10.1016/j.ijbiomac.2023.125837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/27/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
Rv1800 is predicted as PPE family protein found in pathogenic mycobacteria only. Under acidic stress, the rv1800 gene was expressed in M. tuberculosis H37Ra. In-silico study showed lipase/esterase activity in C-terminus PE-PPE domain having pentapeptide motif with catalytic Ser-Asp-His residue. Full-length Rv1800 and C-terminus PE-PPE domain proteins showed esterase activity with pNP-C4 at the optimum temperature of 40 °C and pH 8.0. However, the N-terminus PPE domain showed no esterase activity, but involved in thermostability of Rv1800 full-length protein. M. smegmatis expressing rv1800 (MS_Rv1800) showed altered colony morphology and a significant resistance to numerous environmental stresses, antibiotics and higher lipid content. In extracellular and membrane fraction, Rv1800 protein was detected, while C terminus PE-PPE was present in cytoplasm, suggesting the role of N-terminus PPE domain in transportation of protein. MS_Rv1800 infected macrophage showed higher intracellular survival and low production of ROS, NO and expression levels of iNOS and pro-inflammatory cytokines, while induced expression of the anti-inflammatory cytokines. The Rv1800, PPE and PE-PPE showed antibody-mediated immunity in MDR-TB and PTB patients. Overall, these results confirmed the esterase activity in the C-terminus and function of N-terminus in thermostabilization and transportation; predicting the role of Rv1800 in immune/lipid modulation to support intracellular mycobacterium survival.
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Affiliation(s)
- Pradeep Kumar Anand
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India
| | - Varinder Saini
- Department of Pulmonary Medicine, Government Medical College and Hospital, Chandigarh, India
| | - Jasbinder Kaur
- Department of Biochemistry, Government Medical College and Hospital, Chandigarh, India
| | - Arbind Kumar
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India
| | - Jagdeep Kaur
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India.
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The EspN transcription factor is an infection-dependent regulator of the ESX-1 system in M. marinum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528779. [PMID: 36824794 PMCID: PMC9948972 DOI: 10.1101/2023.02.15.528779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Bacterial pathogens use protein secretion systems to translocate virulence factors into the host and to control bacterial gene expression. The ESX-1 (ESAT-6 system 1) secretion system facilitates disruption of the macrophage phagosome during infection, enabling access to the cytoplasm, and regulates widespread gene expression in the mycobacterial cell. The transcription factors contributing to the ESX-1 transcriptional network during mycobacterial infection are not known. We showed that the EspM and WhiB6 transcription factors regulate the ESX-1 transcriptional network in vitro but are dispensable for macrophage infection by Mycobacterium marinum . In this study, we used our understanding of the ESX-1 system to identify EspN, a critical transcription factor that controls expression of the ESX-1 genes during infection, but whose effect is not detectable under standard laboratory growth conditions. Under laboratory conditions, EspN activity is masked by the EspM repressor. In the absence of EspM, we found that EspN is required for ESX-1 function because it activates expression of the whiB6 transcription factor gene, and specific ESX-1 substrate and secretory component genes. Unlike the other transcription factors that regulate ESX-1, EspN is required for M. marinum growth within and cytolysis of macrophages, and for disease burden in a zebrafish larval model of infection. These findings demonstrate that EspN is an infection-dependent regulator of the ESX-1 transcriptional network, which is essential for mycobacterial pathogenesis. Moreover, our findings suggest that ESX-1 expression is controlled by a genetic switch that responds to host specific signals. Importance Pathogenic mycobacteria cause acute and long-term diseases, including human tuberculosis. The ESX-1 system transports proteins that control the host response to infection and promotes bacterial survival. Although ESX-1 transports proteins, it also controls gene expression in the bacteria. In this study, we identify an undescribed transcription factor that controls the expression of ESX-1 genes, and is required for both macrophage and animal infection. However, this transcription factor is not the primary regulator of ESX-1 genes under standard laboratory conditions. These findings identify a critical transcription factor that controls expression of a major virulence pathway during infection, but whose effect is not detectable with standard laboratory strains and growth conditions.
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Sparks IL, Derbyshire KM, Jacobs WR, Morita YS. Mycobacterium smegmatis: The Vanguard of Mycobacterial Research. J Bacteriol 2023; 205:e0033722. [PMID: 36598232 PMCID: PMC9879119 DOI: 10.1128/jb.00337-22] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The genus Mycobacterium contains several slow-growing human pathogens, including Mycobacterium tuberculosis, Mycobacterium leprae, and Mycobacterium avium. Mycobacterium smegmatis is a nonpathogenic and fast growing species within this genus. In 1990, a mutant of M. smegmatis, designated mc2155, that could be transformed with episomal plasmids was isolated, elevating M. smegmatis to model status as the ideal surrogate for mycobacterial research. Classical bacterial models, such as Escherichia coli, were inadequate for mycobacteria research because they have low genetic conservation, different physiology, and lack the novel envelope structure that distinguishes the Mycobacterium genus. By contrast, M. smegmatis encodes thousands of conserved mycobacterial gene orthologs and has the same cell architecture and physiology. Dissection and characterization of conserved genes, structures, and processes in genetically tractable M. smegmatis mc2155 have since provided previously unattainable insights on these same features in its slow-growing relatives. Notably, tuberculosis (TB) drugs, including the first-line drugs isoniazid and ethambutol, are active against M. smegmatis, but not against E. coli, allowing the identification of their physiological targets. Furthermore, Bedaquiline, the first new TB drug in 40 years, was discovered through an M. smegmatis screen. M. smegmatis has become a model bacterium, not only for M. tuberculosis, but for all other Mycobacterium species and related genera. With a repertoire of bioinformatic and physical resources, including the recently established Mycobacterial Systems Resource, M. smegmatis will continue to accelerate mycobacterial research and advance the field of microbiology.
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Affiliation(s)
- Ian L. Sparks
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Keith M. Derbyshire
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, University at Albany, Albany, New York, USA
| | - William R. Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
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16
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Yan W, Zheng Y, Dou C, Zhang G, Arnaout T, Cheng W. The pathogenic mechanism of Mycobacterium tuberculosis: implication for new drug development. MOLECULAR BIOMEDICINE 2022; 3:48. [PMID: 36547804 PMCID: PMC9780415 DOI: 10.1186/s43556-022-00106-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 11/15/2022] [Indexed: 12/24/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a tenacious pathogen that has latently infected one third of the world's population. However, conventional TB treatment regimens are no longer sufficient to tackle the growing threat of drug resistance, stimulating the development of innovative anti-tuberculosis agents, with special emphasis on new protein targets. The Mtb genome encodes ~4000 predicted proteins, among which many enzymes participate in various cellular metabolisms. For example, more than 200 proteins are involved in fatty acid biosynthesis, which assists in the construction of the cell envelope, and is closely related to the pathogenesis and resistance of mycobacteria. Here we review several essential enzymes responsible for fatty acid and nucleotide biosynthesis, cellular metabolism of lipids or amino acids, energy utilization, and metal uptake. These include InhA, MmpL3, MmaA4, PcaA, CmaA1, CmaA2, isocitrate lyases (ICLs), pantothenate synthase (PS), Lysine-ε amino transferase (LAT), LeuD, IdeR, KatG, Rv1098c, and PyrG. In addition, we summarize the role of the transcriptional regulator PhoP which may regulate the expression of more than 110 genes, and the essential biosynthesis enzyme glutamine synthetase (GlnA1). All these enzymes are either validated drug targets or promising target candidates, with drugs targeting ICLs and LAT expected to solve the problem of persistent TB infection. To better understand how anti-tuberculosis drugs act on these proteins, their structures and the structure-based drug/inhibitor designs are discussed. Overall, this investigation should provide guidance and support for current and future pharmaceutical development efforts against mycobacterial pathogenesis.
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Affiliation(s)
- Weizhu Yan
- grid.412901.f0000 0004 1770 1022Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-Related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041 China
| | - Yanhui Zheng
- grid.412901.f0000 0004 1770 1022Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-Related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041 China
| | - Chao Dou
- grid.412901.f0000 0004 1770 1022Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-Related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041 China
| | - Guixiang Zhang
- grid.13291.380000 0001 0807 1581Division of Gastrointestinal Surgery, Department of General Surgery and Gastric Cancer center, West China Hospital, Sichuan University, No. 37. Guo Xue Xiang, Chengdu, 610041 China
| | - Toufic Arnaout
- Kappa Crystals Ltd., Dublin, Ireland ,MSD Dunboyne BioNX, Co. Meath, Ireland
| | - Wei Cheng
- grid.412901.f0000 0004 1770 1022Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-Related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041 China
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17
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Gijsbers A, Eymery M, Gao Y, Menart I, Vinciauskaite V, Siliqi D, Peters PJ, McCarthy A, Ravelli RBG. The crystal structure of the EspB-EspK virulence factor-chaperone complex suggests an additional type VII secretion mechanism in Mycobacterium tuberculosis. J Biol Chem 2022; 299:102761. [PMID: 36463964 PMCID: PMC9811218 DOI: 10.1016/j.jbc.2022.102761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
Pathogenic species from the Mycobacterium genus are responsible for a number of adverse health conditions in humans and animals that threaten health security and the economy worldwide. Mycobacteria have up to five specialized secretion systems (ESX-1 to ESX-5) that transport virulence factors across their complex cell envelope to facilitate manipulation of their environment. In pathogenic species, these virulence factors influence the immune system's response and are responsible for membrane disruption and contributing to cell death. While structural details of these secretion systems have been recently described, gaps still remain in the structural understanding of the secretion mechanisms of most substrates. Here, we describe the crystal structure of Mycobacterium tuberculosis ESX-1 secretion-associated substrate EspB bound to its chaperone EspK. We found that EspB interacts with the C-terminal domain of EspK through its helical tip. Furthermore, cryogenic electron microscopy, size exclusion chromatography analysis, and small-angle X-ray scattering experiments show that EspK keeps EspB in its secretion-competent monomeric form and prevents its oligomerization. The structure presented in this study suggests an additional secretion mechanism in ESX-1, analogous to the chaperoning of proline-glutamate (PE)-proline-proline-glutamate (PPE) proteins by EspG, where EspK facilitates the secretion of EspB in Mycobacterium species.
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Affiliation(s)
- Abril Gijsbers
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | | | - Ye Gao
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | - Isabella Menart
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | - Vanesa Vinciauskaite
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | - Dritan Siliqi
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Bari, Italy
| | - Peter J Peters
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | | | - Raimond B G Ravelli
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands.
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18
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Bythrow GV, Farhat MF, Levendosky K, Mohandas P, Germain GA, Yoo B, Quadri LEN. Mycobacterium abscessus Mutants with a Compromised Functional Link between the Type VII ESX-3 System and an Iron Uptake Mechanism Reliant on an Unusual Mycobactin Siderophore. Pathogens 2022; 11:pathogens11090953. [PMID: 36145386 PMCID: PMC9505556 DOI: 10.3390/pathogens11090953] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/12/2022] [Accepted: 08/18/2022] [Indexed: 11/28/2022] Open
Abstract
The opportunistic pathogen Mycobacterium abscessus subsp. abscessus (Mab) has become an emerging public health threat due to the increasing number of Mab-associated chronic pulmonary disease cases. Treatment requires multiple drug courses and is often combined with surgical resection. Cure rates are only ~50% due to treatment failure and comorbidities. Deeper understanding of the biology of Mab is required to illuminate potential avenues for the development of better therapeutics against Mab infections. The ESX-3 type VII protein secretion system of Mab has an important role in host inflammatory and pathological responses during infection. In this work, we demonstrate a functional link between ESX-3 and an iron uptake system based on an unusual mycobactin-type siderophore (designated MBT Ab) and exploit this link to implement a large screen for transposon mutants with an impaired ESX-3. Most mutants we identified carry insertions in genes encoding predicted ESX-3 secretion machinery components or potential ESX-3 substrates. The mutants overproduce MBT Ab, a trait consistent with an iron uptake defect. Our characterization of MBT Ab revealed structural features reminiscent of nocardial mycobactin-like compounds with cytotoxicity. This finding raises the possibility that MBT Ab may play roles in pathogenesis unlinked to iron homeostasis. The mutants generated herein will facilitate research to better understand the role of ESX-3 and its interplay with the siderophore system.
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Affiliation(s)
- Glennon V. Bythrow
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Biology Program, Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Manal F. Farhat
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Biology Program, Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Keith Levendosky
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Biology Program, Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Poornima Mohandas
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Biology Program, Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Gabrielle A. Germain
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Biology Program, Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Barney Yoo
- Department of Chemistry, Hunter College, City University of New York, 695 Park Avenue, New York, NY 10065, USA
| | - Luis E. N. Quadri
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Biology Program, Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
- Biochemistry Program, Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
- Correspondence:
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19
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Shu Q, Rajagopal M, Fan J, Zhan L, Kong X, He Y, Rotcheewaphan S, Lyon CJ, Sha W, Zelazny AM, Hu T. Peptidomic analysis of mycobacterial secreted proteins enables species identification. VIEW 2022. [DOI: 10.1002/viw.20210019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Qingbo Shu
- Center for Cellular and Molecular Diagnostics Department of Biochemistry and Molecular Biology School of Medicine Tulane University New Orleans Louisiana USA
| | - Meena Rajagopal
- Department of Laboratory Medicine, Clinical Center National Institutes of Health Bethesda Maryland USA
| | - Jia Fan
- Center for Cellular and Molecular Diagnostics Department of Biochemistry and Molecular Biology School of Medicine Tulane University New Orleans Louisiana USA
| | - Lingpeng Zhan
- Center for Cellular and Molecular Diagnostics Department of Biochemistry and Molecular Biology School of Medicine Tulane University New Orleans Louisiana USA
| | - Xiangxing Kong
- Center for Cellular and Molecular Diagnostics Department of Biochemistry and Molecular Biology School of Medicine Tulane University New Orleans Louisiana USA
| | - Yifan He
- Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital Tongji University School of Medicine Shanghai People's Republic of China
| | - Suwatchareeporn Rotcheewaphan
- Department of Laboratory Medicine, Clinical Center National Institutes of Health Bethesda Maryland USA
- Department of Microbiology, Faculty of Medicine Chulalongkorn University Bangkok Thailand
| | - Christopher J. Lyon
- Center for Cellular and Molecular Diagnostics Department of Biochemistry and Molecular Biology School of Medicine Tulane University New Orleans Louisiana USA
| | - Wei Sha
- Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital Tongji University School of Medicine Shanghai People's Republic of China
| | - Adrian M. Zelazny
- Department of Laboratory Medicine, Clinical Center National Institutes of Health Bethesda Maryland USA
| | - Tony Hu
- Center for Cellular and Molecular Diagnostics Department of Biochemistry and Molecular Biology School of Medicine Tulane University New Orleans Louisiana USA
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20
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Binding of the M. tuberculosis EccC ATPase double hexameric ring to the EsxAB virulence factor is enhanced by ATP. Biochem J 2022; 479:1559-1579. [PMID: 35770799 DOI: 10.1042/bcj20210430] [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: 06/10/2021] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 11/17/2022]
Abstract
The EccC enzyme of M. tuberculosis ESX-1 secretion system is involved in EsxAB virulence factor secretion and offers an attractive target for antivirulence inhibitors development against M. tuberculosis. The EccCb1 polypeptide of the EccC enzyme contains two Ftsk/SpoIIIE type ATPase domains (D2 and D3) and binds to EsxAB factor at C-terminal region of the D3 domain. In current study, we have determined a low-resolution structure of EccCb1, and its mechanism involved in ATPase activity and EsxAB factor binding. Small-angle X-ray scattering data yielded a double hexameric ring structure of EccCb1 in solution and was further confirmed by SEC-MALS and dynamic light scattering. ATPase activity of wild-type, D2, and D3 mutants showed that D2-K90A and D3-K382A mutations led to a complete loss of enzyme activity. The full-length EccCb1 showed ~ 3.7-fold lower catalytic efficiency than D2 domain and ~1.7 fold lower than D3 domain. The EsxAB factor binds EccCb1 with Kd ~ 11.3±0.6 nM and its affinity is enhanced ~2 fold in presence of ATP+Mg2+. These data indicate the involvement of ATPase activity in EsxAB factor translocation. Molecular dynamics simulation on wild-type, ATP+Mg2+ and EsxAB+ATP+Mg2+ bound EccCb1 double-ring structure showed enhanced stability of enzyme upon ATP+Mg2+ and EsxAB binding. Overall, our study showed a low-resolution structure of EccCb1, and the mechanism involved in ATPase activity and EsxAB factor recognition, which can be targeted for the development of anti-virulence drugs against M. tuberculosis.
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Dwivedi M, Bajpai K. The chamber of secretome in Mycobacterium tuberculosis as a potential therapeutic target. Biotechnol Genet Eng Rev 2022; 39:1-44. [PMID: 35613080 DOI: 10.1080/02648725.2022.2076031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Mycobacterium tuberculosis (MTB) causes one of the ancient diseases, Tuberculosis, affects people around the globe and its severity can be understood by its classification as a second infectious disease after COVID-19 and the 13th leading cause of death according to a WHO report. Despite having advanced diagnostic approaches and therapeutic strategies, unfortunately, TB is still spreading across the population due to the emergence of drug-resistance MTB and Latent TB infection (LTBI). We are seeking for effective approaches to overcome these hindrances and efficient treatment for this perilous disease. Therefore, there is an urgent need to develop drugs based on operative targeting of the bacterial system that could result in both efficient treatment and lesser emergence of MDR-TB. One such promising target could be the secretory systems and especially the Type 7 secretory system (T7SS-ESX) of Mycobacterium tuberculosis, which is crucial for the secretion of effector proteins as well as in establishing host-pathogen interactions of the tubercle bacilli. The five paralogous ESX systems (ESX-1 to EXS-5) have been observed by in silico genome analysis of MTB, among which ESX-1 and ESX-5 are substantial for virulence and mediating host cellular inflammasome. The bacterium growth and virulence can be modulated by targeting the T7SS. In the present review, we demonstrate the current status of therapeutics against MTB and focus on the function and cruciality of T7SS along with other secretory systems as a promising therapeutic target against Tuberculosis.
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Affiliation(s)
- Manish Dwivedi
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, India
| | - Kriti Bajpai
- Department of Biotechnology, Himachal Pradesh University, Shimla, India
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22
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Kriel NL, Newton-Foot M, Bennion OT, Aldridge BB, Mehaffy C, Belisle JT, Walzl G, Warren RM, Sampson SL, Gey van Pittius NC. Localization of EccA 3 at the growing pole in Mycobacterium smegmatis. BMC Microbiol 2022; 22:140. [PMID: 35590245 PMCID: PMC9118679 DOI: 10.1186/s12866-022-02554-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/09/2022] [Indexed: 11/30/2022] Open
Abstract
Background Bacteria require specialized secretion systems for the export of molecules into the extracellular space to modify their environment and scavenge for nutrients. The ESX-3 secretion system is required by mycobacteria for iron homeostasis. The ESX-3 operon encodes for one cytoplasmic component (EccA3) and five membrane components (EccB3 – EccE3 and MycP3). In this study we sought to identify the sub-cellular location of EccA3 of the ESX-3 secretion system in mycobacteria. Results Fluorescently tagged EccA3 localized to a single pole in the majority of Mycobacterium smegmatis cells and time-lapse fluorescent microscopy identified this pole as the growing pole. Deletion of ESX-3 did not prevent polar localization of fluorescently tagged EccA3, suggesting that EccA3 unipolar localization is independent of other ESX-3 components. Affinity purification - mass spectrometry was used to identify EccA3 associated proteins which may contribute to the localization of EccA3 at the growing pole. EccA3 co-purified with fatty acid metabolism proteins (FAS, FadA3, KasA and KasB), mycolic acid synthesis proteins (UmaA, CmaA1), cell division proteins (FtsE and FtsZ), and cell shape and cell cycle proteins (MurS, CwsA and Wag31). Secretion system related proteins Ffh, SecA1, EccA1, and EspI were also identified. Conclusions Time-lapse microscopy demonstrated that EccA3 is located at the growing pole in M. smegmatis. The co-purification of EccA3 with proteins known to be required for polar growth, mycolic acid synthesis, the Sec secretion system (SecA1), and the signal recognition particle pathway (Ffh) also suggests that EccA3 is located at the site of active cell growth. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02554-6.
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Affiliation(s)
- Nastassja L Kriel
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
| | - Mae Newton-Foot
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Owen T Bennion
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Bree B Aldridge
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Carolina Mehaffy
- Mycobacteria Research Laboratories, Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523, USA
| | - John T Belisle
- Mycobacteria Research Laboratories, Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gerhard Walzl
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Robin M Warren
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Samantha L Sampson
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nico C Gey van Pittius
- DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research; South African Medical Research Council Centre for Tuberculosis Research; Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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23
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Cuthbert BJ, Hayes CS, Goulding CW. Functional and Structural Diversity of Bacterial Contact-Dependent Growth Inhibition Effectors. Front Mol Biosci 2022; 9:866854. [PMID: 35558562 PMCID: PMC9086364 DOI: 10.3389/fmolb.2022.866854] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/07/2022] [Indexed: 12/25/2022] Open
Abstract
Bacteria live in complex communities and environments, competing for space and nutrients. Within their niche habitats, bacteria have developed various inter-bacterial mechanisms to compete and communicate. One such mechanism is contact-dependent growth inhibition (CDI). CDI is found in many Gram-negative bacteria, including several pathogens. These CDI+ bacteria encode a CdiB/CdiA two-partner secretion system that delivers inhibitory toxins into neighboring cells upon contact. Toxin translocation results in the growth inhibition of closely related strains and provides a competitive advantage to the CDI+ bacteria. CdiB, an outer-membrane protein, secretes CdiA onto the surface of the CDI+ bacteria. When CdiA interacts with specific target-cell receptors, CdiA delivers its C-terminal toxin region (CdiA-CT) into the target-cell. CdiA-CT toxin proteins display a diverse range of toxic functions, such as DNase, RNase, or pore-forming toxin activity. CDI+ bacteria also encode an immunity protein, CdiI, that specifically binds and neutralizes its cognate CdiA-CT, protecting the CDI+ bacteria from auto-inhibition. In Gram-negative bacteria, toxin/immunity (CdiA-CT/CdiI) pairs have highly variable sequences and functions, with over 130 predicted divergent toxin/immunity complex families. In this review, we will discuss biochemical and structural advances made in the characterization of CDI. This review will focus on the diverse array of CDI toxin/immunity complex structures together with their distinct toxin functions. Additionally, we will discuss the most recent studies on target-cell recognition and toxin entry, along with the discovery of a new member of the CDI loci. Finally, we will offer insights into how these diverse toxin/immunity complexes could be harnessed to fight human diseases.
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Affiliation(s)
- Bonnie J. Cuthbert
- Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, United States
| | - Christopher S. Hayes
- Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Celia W. Goulding
- Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, United States
- Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, United States
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24
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Osman MM, Shanahan JK, Chu F, Takaki KK, Pinckert ML, Pagán AJ, Brosch R, Conrad WH, Ramakrishnan L. The C terminus of the mycobacterium ESX-1 secretion system substrate ESAT-6 is required for phagosomal membrane damage and virulence. Proc Natl Acad Sci U S A 2022; 119:e2122161119. [PMID: 35271388 PMCID: PMC8931374 DOI: 10.1073/pnas.2122161119] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/15/2022] [Indexed: 12/21/2022] Open
Abstract
SignificanceTuberculosis (TB), an ancient disease of humanity, continues to be a major cause of worldwide death. The causative agent of TB, Mycobacterium tuberculosis, and its close pathogenic relative Mycobacterium marinum, initially infect, evade, and exploit macrophages, a major host defense against invading pathogens. Within macrophages, mycobacteria reside within host membrane-bound compartments called phagosomes. Mycobacterium-induced damage of the phagosomal membranes is integral to pathogenesis, and this activity has been attributed to the specialized mycobacterial secretion system ESX-1, and particularly to ESAT-6, its major secreted protein. Here, we show that the integrity of the unstructured ESAT-6 C terminus is required for macrophage phagosomal damage, granuloma formation, and virulence.
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Affiliation(s)
- Morwan M. Osman
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Jonathan K. Shanahan
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Frances Chu
- Department of Microbiology, University of Washington, Seattle, WA 98105
| | - Kevin K. Takaki
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Malte L. Pinckert
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Antonio J. Pagán
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Roland Brosch
- Institut Pasteur, Université de Paris, CNRS UMR 3525, Unit for Integrated Mycobacterial Pathogenomics, 75724 Paris Cedex 15, France
| | - William H. Conrad
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
| | - Lalita Ramakrishnan
- Molecular Immunity Unit, Cambridge Institute of Therapeutic Immunology and Infectious Diseases, Department of Medicine, University of Cambridge, CB2 OQH Cambridge, United Kingdom
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, United Kingdom
- Department of Microbiology, University of Washington, Seattle, WA 98105
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25
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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: 14] [Impact Index Per Article: 4.7] [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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26
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Wang Y, Tang Y, Lin C, Zhang J, Mai J, Jiang J, Gao X, Li Y, Zhao G, Zhang L, Liu J. Crosstalk between the ancestral type VII secretion system ESX-4 and other T7SS in Mycobacterium marinum. iScience 2022; 25:103585. [PMID: 35005535 PMCID: PMC8718981 DOI: 10.1016/j.isci.2021.103585] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 10/30/2021] [Accepted: 12/06/2021] [Indexed: 12/13/2022] Open
Abstract
The type VII secretion system (T7SS) of Mycobacterium tuberculosis secretes three substrate classes: Esx, Esp, and PE/PPE proteins, that play important roles in bacterial physiology and host interaction. Five subtypes of T7SS, namely ESX-1 to ESX-5, are present in M. tb. ESX-4 is the progenitor of T7SS but its function is not understood. We investigated the ESX-4 system in Mycobacterium marinum. We show that ESX-4 of M. marinum does not secrete its cognate substrates, EsxT and EsxU, under the conditions tested. Paradoxically, the deletion of eccC4, an essential component of ESX-4, resulted in elevated secretion of protein substrates of ESX-1 and ESX-5. Consequently, the ΔeccC4 mutant was more efficient in inducing actin cytoskeleton rearrangement, which led to enhanced phagocytosis by macrophages. Our results reveal an intimate crosstalk between the progenitor of T7SS and its more recent duplication and expansion, and provide new insight into the evolution of T7SS in mycobacteria.
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Affiliation(s)
- Yuchen Wang
- Department of Microbiology, School of Life Science, Fudan University, Shanghai 200090, China.,Guizhou institute of Biotechnology, Guiyang 550025, Guizhou, China
| | - Yuting Tang
- State Key Laboratory of Genetic Engineering, School of Life Science, Institute of Genetics, Fudan University, Shanghai 200090, China
| | - Chen Lin
- State Key Laboratory of Genetic Engineering, School of Life Science, Institute of Genetics, Fudan University, Shanghai 200090, China
| | - Junli Zhang
- State Key Laboratory of Genetic Engineering, School of Life Science, Institute of Genetics, Fudan University, Shanghai 200090, China
| | - Juntao Mai
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G1M1, Canada
| | - Jun Jiang
- State Key Laboratory of Genetic Engineering, School of Life Science, Institute of Genetics, Fudan University, Shanghai 200090, China
| | - Xiaoxiao Gao
- State Key Laboratory of Genetic Engineering, School of Life Science, Institute of Genetics, Fudan University, Shanghai 200090, China
| | - Yao Li
- State Key Laboratory of Genetic Engineering, School of Life Science, Institute of Genetics, Fudan University, Shanghai 200090, China
| | - Guoping Zhao
- Department of Microbiology, School of Life Science, Fudan University, Shanghai 200090, China
| | - Lu Zhang
- Department of Microbiology, School of Life Science, Fudan University, Shanghai 200090, China.,State Key Laboratory of Genetic Engineering, School of Life Science, Institute of Genetics, Fudan University, Shanghai 200090, China.,Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai 200090, China
| | - Jun Liu
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G1M1, Canada
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27
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Bao Y, Wang L, Sun J. Post-translational knockdown and post-secretional modification of EsxA determine contribution of EsxA membrane permeabilizing activity for mycobacterial intracellular survival. Virulence 2021; 12:312-328. [PMID: 33356823 PMCID: PMC7808419 DOI: 10.1080/21505594.2020.1867438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 12/10/2020] [Accepted: 12/17/2020] [Indexed: 12/15/2022] Open
Abstract
Current genetic studies (e.g. gene knockout) have suggested that EsxA and EsxB function as secreted virulence factors that are essential for Mycobaterium tuberculosis (Mtb) intracellular survival, specifically in mediating phagosome rupture and translocation of Mtb to the cytosol of host cells, which further facilitates Mtb intracellular replicating and cell-to-cell spreading. The EsxA-mediated intracellular survival is presumably achieved by its pH-dependent membrane-permeabilizing activity (MPA). However, the data from other studies have generated a discrepancy regarding the role of EsxA MPA in mycobacterial intracellular survival, which has raised a concern that genetic manipulations, such as deletion of esxB-esxA operon or RD-1 locus, may affect other codependently secreted factors that could be also directly involved cytosolic translocation, or stimulate extended disturbance on other genes' expression. To avoid the drawbacks of gene knockout, we first engineered a Mycobacterium marinum (Mm) strain, in which a DAS4+ tag was fused to the C-terminus of EsxB to allow inducible knockdown of EsxB (also EsxA) at the post-translational level. We also engineered an Mm strain by fusing a SpyTag (ST) to the C-terminus of EsxA, which allowed inhibition of EsxA-ST MPA at the post-secretional level through a covalent linkage to SpyCatcher-GFP. Both post-translational knockdown and functional inhibition of EsxA resulted in attenuation of Mm intracellular survival in lung epithelial cells or macrophages, which unambiguously confirms the direct role of EsxA MPA in mycobacterial intracellular survival.
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Affiliation(s)
- Yanqing Bao
- Department of Biological Sciences and Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas, USA
| | - Lin Wang
- Department of Biological Sciences and Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas, USA
| | - Jianjun Sun
- Department of Biological Sciences and Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas, USA
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28
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Abstract
Animal tuberculosis (TB) is an emergent disease caused by Mycobacterium bovis, one of the animal-adapted ecotypes of the Mycobacterium tuberculosis complex (MTC). In this work, whole-genome comparative analyses of 70 M. bovis were performed to gain insights into the pan-genome architecture. The comparison across M. bovis predicted genome composition enabled clustering into the core- and accessory-genome components, with 2736 CDS for the former, while the accessory moiety included 3897 CDS, of which 2656 are restricted to one/two genomes only. These analyses predicted an open pan-genome architecture, with an average of 32 CDS added by each genome and show the diversification of discrete M. bovis subpopulations supported by both core- and accessory-genome components. The functional annotation of the pan-genome classified each CDS into one or several COG (Clusters of Orthologous Groups) categories, revealing ‘transcription’ (total average CDSs, n=258), ‘lipid metabolism and transport’ (n=242), ‘energy production and conversion’ (n=214) and ‘unknown function’ (n=876) as the most represented. The closer analysis of polymorphisms in virulence-related genes in a restrict group of M. bovis from a multi-host system enabled the identification of clade-monomorphic non-synonymous SNPs, illustrating clade-specific virulence landscapes and correlating with disease severity. This first comparative pan-genome study of a diverse collection of M. bovis encompassing all clonal complexes indicates a high percentage of accessory genes and denotes an open, dynamic non-conservative pan-genome structure, with high evolutionary potential, defying the canons of MTC biology. Furthermore, it shows that M. bovis can shape its virulence repertoire, either by acquisition and loss of genes or by SNP-based diversification, likely towards host immune evasion, adaptation and persistence.
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Affiliation(s)
- Ana C Reis
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal.,Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Mónica V Cunha
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal.,Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
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29
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Mycobacterium tuberculosis Rv0292 Protein Peptides Could be Included in a Synthetic Anti-tuberculosis Vaccine. Int J Pept Res Ther 2021. [DOI: 10.1007/s10989-021-10292-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Rivera-Calzada A, Famelis N, Llorca O, Geibel S. Type VII secretion systems: structure, functions and transport models. Nat Rev Microbiol 2021; 19:567-584. [PMID: 34040228 DOI: 10.1038/s41579-021-00560-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2021] [Indexed: 02/07/2023]
Abstract
Type VII secretion systems (T7SSs) have a key role in the secretion of effector proteins in non-pathogenic mycobacteria and pathogenic mycobacteria such as Mycobacterium tuberculosis, the main causative agent of tuberculosis. Tuberculosis-causing mycobacteria, still accounting for 1.4 million deaths annually, rely on paralogous T7SSs to survive in the host and efficiently evade its immune response. Although it is still unknown how effector proteins of T7SSs cross the outer membrane of the diderm mycobacterial cell envelope, recent advances in the structural characterization of these secretion systems have revealed the intricate network of interactions of conserved components in the plasma membrane. This structural information, added to recent advances in the molecular biology and regulation of mycobacterial T7SSs as well as progress in our understanding of their secreted effector proteins, is shedding light on the inner working of the T7SS machinery. In this Review, we highlight the implications of these studies and the derived transport models, which provide new scenarios for targeting the deathly human pathogen M. tuberculosis.
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Affiliation(s)
- Angel Rivera-Calzada
- Structural Biology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
| | - Nikolaos Famelis
- Institute for Molecular Infection Biology, Julius-Maximilian University of Würzburg, Würzburg, Germany.,Rudolf Virchow Center for Integrative and Translational Biomedicine, Julius-Maximilian University of Würzburg, Würzburg, Germany
| | - Oscar Llorca
- Structural Biology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Sebastian Geibel
- Institute for Molecular Infection Biology, Julius-Maximilian University of Würzburg, Würzburg, Germany. .,Rudolf Virchow Center for Integrative and Translational Biomedicine, Julius-Maximilian University of Würzburg, Würzburg, Germany.
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31
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Vatlin AA, Shitikov EA, Shahbaaz M, Bespiatykh DA, Klimina KM, Christoffels A, Danilenko VN, Maslov DA. Transcriptomic Profile of Mycobacterium smegmatis in Response to an Imidazo[1,2- b][1,2,4,5]tetrazine Reveals Its Possible Impact on Iron Metabolism. Front Microbiol 2021; 12:724042. [PMID: 34421882 PMCID: PMC8371482 DOI: 10.3389/fmicb.2021.724042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/14/2021] [Indexed: 12/03/2022] Open
Abstract
Tuberculosis (TB), caused by the Mycobacterium tuberculosis complex bacteria, is one of the most pressing health problems. The development of new drugs and new therapeutic regimens effective against the pathogen is one of the greatest challenges in the way of tuberculosis control. Imidazo[1,2-b][1,2,4,5]tetrazines have shown promising activity against M. tuberculosis and M. smegmatis strains. Mutations in MSMEG_1380 lead to mmpS5–mmpL5 operon overexpression, which provides M. smegmatis with efflux-mediated resistance to imidazo[1,2-b][1,2,4,5]tetrazines, but the exact mechanism of action of these compounds remains unknown. To assess the mode of action of imidazo[1,2-b][1,2,4,5]tetrazines, we analyzed the transcriptomic response of M. smegmatis to three different concentrations of 3a compound: 1/8×, 1/4×, and 1/2× MIC. Six groups of genes responsible for siderophore synthesis and transport were upregulated in a dose-dependent manner, while virtual docking revealed proteins involved in siderophore synthesis as possible targets for 3a. Thus, we suggest that imidazo[1,2-b][1,2,4,5]tetrazines may affect mycobacterial iron metabolism.
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Affiliation(s)
- Aleksey A Vatlin
- Laboratory of Bacterial Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, Russia.,Peoples' Friendship University of Russia (RUDN University), Moscow, Russia
| | - Egor A Shitikov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Mohd Shahbaaz
- South Africa Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Cape Town, South Africa
| | - Dmitry A Bespiatykh
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Ksenia M Klimina
- Laboratory of Bacterial Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, Russia.,Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Alan Christoffels
- South Africa Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Cape Town, South Africa
| | - Valery N Danilenko
- Laboratory of Bacterial Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, Russia
| | - Dmitry A Maslov
- Laboratory of Bacterial Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, Moscow, Russia
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32
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Lagune M, Petit C, Sotomayor FV, Johansen MD, Beckham KSH, Ritter C, Girard-Misguich F, Wilmanns M, Kremer L, Maurer FP, Herrmann JL. Conserved and specialized functions of Type VII secretion systems in non-tuberculous mycobacteria. MICROBIOLOGY-SGM 2021; 167. [PMID: 34224347 DOI: 10.1099/mic.0.001054] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Non-tuberculous mycobacteria (NTM) are a large group of micro-organisms comprising more than 200 individual species. Most NTM are saprophytic organisms and are found mainly in terrestrial and aquatic environments. In recent years, NTM have been increasingly associated with infections in both immunocompetent and immunocompromised individuals, prompting significant efforts to understand the diverse pathogenic and signalling traits of these emerging pathogens. Since the discovery of Type VII secretion systems (T7SS), there have been significant developments regarding the role of these complex systems in mycobacteria. These specialised systems, also known as Early Antigenic Secretion (ESX) systems, are employed to secrete proteins across the inner membrane. They also play an essential role in virulence, nutrient uptake and conjugation. Our understanding of T7SS in mycobacteria has significantly benefited over the last few years, from the resolution of ESX-3 structure in Mycobacterium smegmatis, to ESX-5 structures in Mycobacterium xenopi and Mycobacterium tuberculosis. In addition, ESX-4, considered until recently as a non-functional system in both pathogenic and non-pathogenic mycobacteria, has been proposed to play an important role in the virulence of Mycobacterium abscessus; an increasingly recognized opportunistic NTM causing severe lung diseases. These major findings have led to important new insights into the functional mechanisms of these biological systems, their implication in virulence, nutrient acquisitions and cell wall shaping, and will be discussed in this review.
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Affiliation(s)
- Marion Lagune
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France
| | - Cecile Petit
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Flor Vásquez Sotomayor
- National and WHO Supranational Reference Center for Mycobacteria, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Matt D Johansen
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293, Montpellier, France.,Present address: Centre for Inflammation, Centenary Institute and University of Technology Sydney, Faculty of Science, Sydney, NSW, Australia
| | - Kathrine S H Beckham
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Christina Ritter
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Fabienne Girard-Misguich
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France
| | - Matthias Wilmanns
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany.,University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20251 Hamburg, Germany
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR 9004, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, 1919 route de Mende, 34293, Montpellier, France.,INSERM, IRIM, 34293 Montpellier, France
| | - 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
| | - Jean-Louis Herrmann
- Université Paris-Saclay, UVSQ, Inserm, Infection et inflammation, 78180, Montigny-Le-Bretonneux, France.,APHP, GHU Paris-Saclay, Hôpital Raymond Poincaré, Service de Microbiologie, Garches, France
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Lara AC, Corretto E, Kotrbová L, Lorenc F, Petříčková K, Grabic R, Chroňáková A. The Genome Analysis of the Human Lung-Associated Streptomyces sp. TR1341 Revealed the Presence of Beneficial Genes for Opportunistic Colonization of Human Tissues. Microorganisms 2021; 9:1547. [PMID: 34442631 PMCID: PMC8401907 DOI: 10.3390/microorganisms9081547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/12/2021] [Accepted: 07/17/2021] [Indexed: 12/16/2022] Open
Abstract
Streptomyces sp. TR1341 was isolated from the sputum of a man with a history of lung and kidney tuberculosis, recurrent respiratory infections, and COPD. It produces secondary metabolites associated with cytotoxicity and immune response modulation. In this study, we complement our previous results by identifying the genetic features associated with the production of these secondary metabolites and other characteristics that could benefit the strain during its colonization of human tissues (virulence factors, modification of the host immune response, or the production of siderophores). We performed a comparative phylogenetic analysis to identify the genetic features that are shared by environmental isolates and human respiratory pathogens. The results showed a high genomic similarity of Streptomyces sp. TR1341 to the plant-associated Streptomyces sp. endophyte_N2, inferring a soil origin of the strain. Putative virulence genes, such as mammalian cell entry (mce) genes were not detected in the TR1341's genome. The presence of a type VII secretion system, distinct from the ones found in Mycobacterium species, suggests a different colonization strategy than the one used by other actinomycete lung pathogens. We identified a higher diversity of genes related to iron acquisition and demonstrated that the strain produces ferrioxamine B in vitro. These results indicate that TR1341 may have an advantage in colonizing environments that are low in iron, such as human tissue.
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Affiliation(s)
- Ana Catalina Lara
- Institute of Soil Biology, Biology Centre Academy of Sciences of The Czech Republic, Na Sádkách 702/7, 37005 České Budějovice, Czech Republic; (A.C.L.); (E.C.); (L.K.); (F.L.)
| | - Erika Corretto
- Institute of Soil Biology, Biology Centre Academy of Sciences of The Czech Republic, Na Sádkách 702/7, 37005 České Budějovice, Czech Republic; (A.C.L.); (E.C.); (L.K.); (F.L.)
| | - Lucie Kotrbová
- Institute of Soil Biology, Biology Centre Academy of Sciences of The Czech Republic, Na Sádkách 702/7, 37005 České Budějovice, Czech Republic; (A.C.L.); (E.C.); (L.K.); (F.L.)
| | - František Lorenc
- Institute of Soil Biology, Biology Centre Academy of Sciences of The Czech Republic, Na Sádkách 702/7, 37005 České Budějovice, Czech Republic; (A.C.L.); (E.C.); (L.K.); (F.L.)
| | - Kateřina Petříčková
- Institute of Immunology and Microbiology, 1st Faculty of Medicine, Charles University, Studničkova 7, 12800 Prague 2, Czech Republic;
- Faculty of Science, University of South Bohemia, Branišovská 1645/31a, 37005 České Budějovice, Czech Republic
| | - Roman Grabic
- Faculty of Fisheries and Protection of Waters, University of South Bohemia, Zátiší 728/II, 38925 Vodňany, Czech Republic;
| | - Alica Chroňáková
- Institute of Soil Biology, Biology Centre Academy of Sciences of The Czech Republic, Na Sádkách 702/7, 37005 České Budějovice, Czech Republic; (A.C.L.); (E.C.); (L.K.); (F.L.)
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De Maio F, Berisio R, Manganelli R, Delogu G. PE_PGRS proteins of Mycobacterium tuberculosis: A specialized molecular task force at the forefront of host-pathogen interaction. Virulence 2021; 11:898-915. [PMID: 32713249 PMCID: PMC7550000 DOI: 10.1080/21505594.2020.1785815] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
To the PE_PGRS protein subfamily belongs a group of surface-exposed mycobacterial antigens that in Mycobacterium tuberculosis (Mtb) H37Rv accounts to more than 65 genes, 51 of which are thought to express a functional protein. PE_PGRS proteins share a conserved structural architecture with three main domains: the N-terminal PE domain; the PGRS domain, that can vary in sequence and size and is characterized by the presence of multiple GGA-GGX amino acid repeats; the highly conserved sequence containing the GRPLI motif that links the PE and PGRS domains; the unique C-terminus end that can vary in size from few to up to ≈ 300 amino acids. pe_pgrs genes emerged in slow-growing mycobacteria and expanded and diversified in MTBC and few other pathogenic mycobacteria. Interestingly, despite sequence homology and apparent redundancy, PE_PGRS proteins seem to have evolved a peculiar function. In this review, we summarize the actual knowledge on this elusive protein family in terms of evolution, structure, and function, focusing on the role of PE_PGRS in TB pathogenesis. We provide an original hypothesis on the role of the PE domain and propose a structural model for the polymorphic PGRS domain that might explain how so similar proteins can have different physiological functions.
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Affiliation(s)
- Flavio De Maio
- Dipartimento di Scienze di Laboratorio e Infettivologiche, Fondazione Policlinico Universitario "A. Gemelli" , Rome, Italy.,Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie - Sezione di Microbiologia, Università Cattolica del Sacro Cuore , Rome, Italy
| | - Rita Berisio
- Institute of Bio-Structures and Bio-Imaging - CNR-IBB , Naples, Italy
| | | | - Giovanni Delogu
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie - Sezione di Microbiologia, Università Cattolica del Sacro Cuore , Rome, Italy.,Mater Olbia Hospital , Olbia, Italy
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35
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Gijsbers A, Vinciauskaite V, Siroy A, Gao Y, Tria G, Mathew A, Sánchez-Puig N, López-Iglesias C, Peters PJ, Ravelli RBG. Priming mycobacterial ESX-secreted protein B to form a channel-like structure. Curr Res Struct Biol 2021; 3:153-164. [PMID: 34337436 PMCID: PMC8313811 DOI: 10.1016/j.crstbi.2021.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/20/2021] [Accepted: 06/17/2021] [Indexed: 01/24/2023] Open
Abstract
ESX-1 is a major virulence factor of Mycobacterium tuberculosis, a secretion machinery directly involved in the survival of the microorganism from the immune system defence. It disrupts the phagosome membrane of the host cell through a contact-dependent mechanism. Recently, the structure of the inner-membrane core complex of the homologous ESX-3 and ESX-5 was resolved; however, the elements involved in the secretion through the outer membrane or those acting on the host cell membrane are unknown. Protein substrates might form this missing element. Here, we describe the oligomerisation process of the ESX-1 substrate EspB, which occurs upon cleavage of its C-terminal region and is favoured by an acidic environment. Cryo-electron microscopy data shows that quaternary structure of EspB is conserved across slow growing species, but not in the fast growing M. smegmatis. EspB assembles into a channel with dimensions and characteristics suitable for the transit of ESX-1 substrates, as shown by the presence of another EspB trapped within. Our results provide insight into the structure and assembly of EspB, and suggests a possible function as a structural element of ESX-1.
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Affiliation(s)
- Abril Gijsbers
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
| | - Vanesa Vinciauskaite
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
| | - Axel Siroy
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
| | - Ye Gao
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
| | - Giancarlo Tria
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
| | - Anjusha Mathew
- Division of Imaging Mass Spectrometry, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
| | - Nuria Sánchez-Puig
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
- Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Ciudad de México, 04510, Mexico
| | - Carmen López-Iglesias
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
| | - Peter J Peters
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
| | - Raimond B G Ravelli
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, the Netherlands
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Genome-Wide Essentiality Analysis of Mycobacterium abscessus by Saturated Transposon Mutagenesis and Deep Sequencing. mBio 2021; 12:e0104921. [PMID: 34126767 PMCID: PMC8262987 DOI: 10.1128/mbio.01049-21] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium abscessus is an emerging opportunistic human pathogen that naturally resists most major classes of antibiotics, making infections difficult to treat. Thus far, little is known about M. abscessus physiology, pathogenesis, and drug resistance. Genome-wide analyses have comprehensively catalogued genes with essential functions in Mycobacterium tuberculosis and Mycobacterium avium subsp. hominissuis (here, M. avium) but not in M. abscessus. By optimizing transduction conditions, we achieved full saturation of TA insertion sites with Himar1 transposon mutagenesis in the M. abscessus ATCC 19977T genome, as confirmed by deep sequencing prior to essentiality analyses of annotated genes and other genomic features. The overall densities of inserted TA sites (85.7%), unoccupied TA sites (14.3%), and nonpermissive TA sites (8.1%) were similar to results in M. tuberculosis and M. avium. Of the 4,920 annotated genes, 326 were identified as essential, 269 (83%) of which have mutual homology with essential M. tuberculosis genes, while 39 (12%) are homologous to genes that are not essential in M. tuberculosis and M. avium, and 11 (3.4%) only have homologs in M. avium. Interestingly, 7 (2.1%) essential M. abscessus genes have no homologs in either M. tuberculosis or M. avium, two of which were found in phage-like elements. Most essential genes are involved in DNA replication, RNA transcription and translation, and posttranslational events to synthesize important macromolecules. Some essential genes may be involved in M. abscessus pathogenesis and antibiotics response, including certain essential tRNAs and new short open reading frames. Our findings will help to pave the way for better understanding of M. abscessus and benefit development of novel bactericidal drugs against M. abscessus. IMPORTANCE Limited knowledge regarding Mycobacterium abscessus pathogenesis and intrinsic resistance to most classes of antibiotics is a major obstacle to developing more effective strategies to prevent and mitigate disease. Using optimized procedures for Himar1 transposon mutagenesis and deep sequencing, we performed a comprehensive analysis to identify M. abscessus genetic elements essential for in vitro growth and compare them to similar data sets for M. tuberculosis and M. avium subsp. hominissuis. Most essential M. abscessus genes have mutual homology with essential M. tuberculosis genes, providing a foundation for leveraging available knowledge from M. tuberculosis to develop more effective drugs and other interventions against M. abscessus. A small number of essential genes unique to M. abscessus deserve further attention to gain insights into what makes M. abscessus different from other mycobacteria. The essential genes and other genomic features such as short open reading frames and noncoding RNA identified here will provide useful information for future study of M. abscessus pathogenicity and new drug development.
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37
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Ehtram A, Shariq M, Ali S, Quadir N, Sheikh JA, Ahmad F, Sharma T, Ehtesham NZ, Hasnain SE. Teleological cooption of Mycobacterium tuberculosis PE/PPE proteins as porins: Role in molecular immigration and emigration. Int J Med Microbiol 2021; 311:151495. [PMID: 33730677 DOI: 10.1016/j.ijmm.2021.151495] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 02/01/2021] [Accepted: 03/05/2021] [Indexed: 01/09/2023] Open
Abstract
Permeation through bacterial cells for exchange or uptake of biomolecules and ions invariably depend upon the existence of pore-forming proteins (porins) in their outer membrane. Mycobacterium tuberculosis (M. tb) harbours one of the most rigid cell envelopes across bacterial genera and is devoid of the classical porins for solute transport across the cell membrane. Though canonical porins are incompatible with the evolution of permeability barrier, porin like activity has been reported from membrane preparations of pathogenic mycobacteria. This suggests a sophisticated transport mechanism that has been elusive until now, along with the protein family responsible for it. Recent evidence suggests that these slow-growing mycobacteria have co-opted some of PE/PPE family proteins as molecular transport channels, in place of porins, to facilitate uptake of nutrients required to thrive in the restrictive host environment. These reports advocate that PE/PPE proteins, due to their structural ability, have a potential role in importing small molecules to the cell's interior. This mechanism unveils how a successful pathogen overcomes its restrictive membrane's transport limitations for selective uptake of nutrients. If extrapolated to have a role in drug transport, these channels could help understand the emergence of drug resistance. Further, as these proteins are associated with the export of virulence factors, they can be exploited as novel drug targets. There remains, however, an interesting question that as the PE/PPE proteins can allow the 'import' of molecules from outside the cell, is the reverse transport also possible across the M. tb membrane. In this review, we have discussed recent evidence supporting PE/PPE's role as a specific transport channel for selective uptake of small molecule nutrients and, as possible molecular export machinery of M. tb. This newly discovered role as transmembrane channels demands further research on this enigmatic family of proteins to comprehend the pathomechanism of this very smart pathogen.
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Affiliation(s)
- Aquib Ehtram
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Mohd Shariq
- ICMR-National Institute of Pathology, Ansari Nagar West, New Delhi, India
| | - Sabeeha Ali
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Neha Quadir
- ICMR-National Institute of Pathology, Ansari Nagar West, New Delhi, India; Jamia Hamdard- Institute of Molecular Medicine, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Javaid A Sheikh
- Department of Biotechnology, School of Chemical and Life Sciences, Jamia Hamdard, Hamdard Nagar, New Delhi, 110062, India
| | - Faraz Ahmad
- ICMR-National Institute of Pathology, Ansari Nagar West, New Delhi, India
| | - Tarina Sharma
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India; ICMR-National Institute of Pathology, Ansari Nagar West, New Delhi, India
| | - Nasreen Z Ehtesham
- ICMR-National Institute of Pathology, Ansari Nagar West, New Delhi, India.
| | - Seyed E Hasnain
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India; Dr Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, India.
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Izquierdo Lafuente B, Ummels R, Kuijl C, Bitter W, Speer A. Mycobacterium tuberculosis Toxin CpnT Is an ESX-5 Substrate and Requires Three Type VII Secretion Systems for Intracellular Secretion. mBio 2021; 12:e02983-20. [PMID: 33653883 PMCID: PMC8092274 DOI: 10.1128/mbio.02983-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/25/2021] [Indexed: 11/20/2022] Open
Abstract
CpnT, a NAD+ glycohydrolase, is the only known toxin that is secreted by Mycobacterium tuberculosis CpnT is composed of two domains; the C-terminal domain is the toxin, whereas the N-terminal domain is required for secretion. CpnT shows characteristics of type VII secretion (T7S) substrates, including a predicted helix-turn-helix domain followed by a secretion motif (YxxxE). Disruption of this motif indeed abolished CpnT secretion. By analyzing different mutants, we established that CpnT is specifically secreted by the ESX-5 system in Mycobacterium marinum under axenic conditions and during macrophage infection. Surprisingly, intracellular secretion of CpnT was also dependent on both ESX-1 and ESX-4. These secretion defects could be partially rescued by coinfection with wild-type bacteria, indicating that secreted effectors are involved in this process. In summary, our data reveal that three different type VII secretion systems have to be functional in order to observe intracellular secretion of the toxin CpnT.IMPORTANCE For decades, it was believed that the intracellular pathogen M. tuberculosis does not possess toxins. Only fairly recently it was discovered that CpnT is a potent secreted toxin of M. tuberculosis, causing necrotic cell death in host cells. However, until now the secretion pathway remained unknown. In our study, we were able to identify CpnT as a substrate of the mycobacterial type VII secretion system. Pathogenic mycobacteria have up to five different type VII secretion systems, called ESX-1 to ESX-5, which play distinct roles for the pathogen during growth or infection. We were able to elucidate that CpnT is exclusively secreted by the ESX-5 system in bacterial culture. However, to our surprise we discovered that, during infection studies, CpnT secretion relies on intact ESX-1, ESX-4, and ESX-5 systems. We elucidate for the first time the intertwined interplay of three different and independent secretion systems to secrete one substrate during infection.
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Affiliation(s)
- B Izquierdo Lafuente
- Section of Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - R Ummels
- Department of Medical Microbiology and Infection Control, Amsterdam UMC, Location VU Medical Center, Amsterdam, The Netherlands
| | - C Kuijl
- Department of Medical Microbiology and Infection Control, Amsterdam UMC, Location VU Medical Center, Amsterdam, The Netherlands
| | - W Bitter
- Section of Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Medical Microbiology and Infection Control, Amsterdam UMC, Location VU Medical Center, Amsterdam, The Netherlands
| | - A Speer
- Department of Medical Microbiology and Infection Control, Amsterdam UMC, Location VU Medical Center, Amsterdam, The Netherlands
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Ageorges V, Monteiro R, Leroy S, Burgess CM, Pizza M, Chaucheyras-Durand F, Desvaux M. Molecular determinants of surface colonisation in diarrhoeagenic Escherichia coli (DEC): from bacterial adhesion to biofilm formation. FEMS Microbiol Rev 2021; 44:314-350. [PMID: 32239203 DOI: 10.1093/femsre/fuaa008] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/31/2020] [Indexed: 12/11/2022] Open
Abstract
Escherichia coli is primarily known as a commensal colonising the gastrointestinal tract of infants very early in life but some strains being responsible for diarrhoea, which can be especially severe in young children. Intestinal pathogenic E. coli include six pathotypes of diarrhoeagenic E. coli (DEC), namely, the (i) enterotoxigenic E. coli, (ii) enteroaggregative E. coli, (iii) enteropathogenic E. coli, (iv) enterohemorragic E. coli, (v) enteroinvasive E. coli and (vi) diffusely adherent E. coli. Prior to human infection, DEC can be found in natural environments, animal reservoirs, food processing environments and contaminated food matrices. From an ecophysiological point of view, DEC thus deal with very different biotopes and biocoenoses all along the food chain. In this context, this review focuses on the wide range of surface molecular determinants acting as surface colonisation factors (SCFs) in DEC. In the first instance, SCFs can be broadly discriminated into (i) extracellular polysaccharides, (ii) extracellular DNA and (iii) surface proteins. Surface proteins constitute the most diverse group of SCFs broadly discriminated into (i) monomeric SCFs, such as autotransporter (AT) adhesins, inverted ATs, heat-resistant agglutinins or some moonlighting proteins, (ii) oligomeric SCFs, namely, the trimeric ATs and (iii) supramolecular SCFs, including flagella and numerous pili, e.g. the injectisome, type 4 pili, curli chaperone-usher pili or conjugative pili. This review also details the gene regulatory network of these numerous SCFs at the various stages as it occurs from pre-transcriptional to post-translocational levels, which remains to be fully elucidated in many cases.
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Affiliation(s)
- Valentin Ageorges
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Ricardo Monteiro
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,GSK, Via Fiorentina 1, 53100 Siena, Italy
| | - Sabine Leroy
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Catherine M Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
| | | | - Frédérique Chaucheyras-Durand
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,Lallemand Animal Nutrition SAS, F-31702 Blagnac Cedex, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
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40
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Tran HKR, Grebenc DW, Klein TA, Whitney JC. Bacterial type VII secretion: An important player in host-microbe and microbe-microbe interactions. Mol Microbiol 2021; 115:478-489. [PMID: 33410158 DOI: 10.1111/mmi.14680] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 12/19/2022]
Abstract
Type VII secretion systems (T7SSs) are poorly understood protein export apparatuses found in mycobacteria and many species of Gram-positive bacteria. To date, this pathway has predominantly been studied in Mycobacterium tuberculosis, where it has been shown to play an essential role in virulence; however, much less studied is an evolutionarily divergent subfamily of T7SSs referred to as the T7SSb. The T7SSb is found in the major Gram-positive phylum Firmicutes where it was recently shown to target both eukaryotic and prokaryotic cells, suggesting a dual role for this pathway in host-microbe and microbe-microbe interactions. In this review, we compare the current understanding of the molecular architectures and substrate repertoires of the well-studied mycobacterial T7SSa systems to that of recently characterized T7SSb pathways and highlight how these differences may explain the observed biological functions of this understudied protein export machine.
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Affiliation(s)
- Hiu-Ki R Tran
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Dirk W Grebenc
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Timothy A Klein
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - John C Whitney
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, ON, Canada
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Pore-forming Esx proteins mediate toxin secretion by Mycobacterium tuberculosis. Nat Commun 2021; 12:394. [PMID: 33452244 PMCID: PMC7810871 DOI: 10.1038/s41467-020-20533-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 11/25/2020] [Indexed: 01/29/2023] Open
Abstract
Mycobacterium tuberculosis secretes the tuberculosis necrotizing toxin (TNT) to kill host cells. Here, we show that the WXG100 proteins EsxE and EsxF are essential for TNT secretion. EsxE and EsxF form a water-soluble heterodimer (EsxEF) that assembles into oligomers and long filaments, binds to membranes, and forms stable membrane-spanning channels. Electron microscopy of EsxEF reveals mainly pentameric structures with a central pore. Mutations of both WXG motifs and of a GXW motif do not affect dimerization, but abolish pore formation, membrane deformation and TNT secretion. The WXG/GXW mutants are locked in conformations with altered thermostability and solvent exposure, indicating that the WXG/GXW motifs are molecular switches controlling membrane interaction and pore formation. EsxF is accessible on the bacterial cell surface, suggesting that EsxEF form an outer membrane channel for toxin export. Thus, our study reveals a protein secretion mechanism in bacteria that relies on pore formation by small WXG proteins.
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42
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Structural Analysis of the Partially Disordered Protein EspK from Mycobacterium Tuberculosis. CRYSTALS 2020. [DOI: 10.3390/cryst11010018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
For centuries, tuberculosis has been a worldwide burden for human health, and gaps in our understanding of its pathogenesis have hampered the development of new treatments. ESX-1 is a complex machinery responsible for the secretion of virulence factors that manipulate the host response. Despite the importance of these secreted proteins for pathogenicity, only a few of them have been structurally and functionally characterised. Here, we describe a structural study of the ESX-secretion associated protein K (EspK), a 74 kDa protein known to be essential for the secretion of other substrates and the cytolytic effects of ESX-1. Small-Angle X-ray Scattering (SAXS) data show that EspK is a long molecule with a maximal dimension of 228 Å. It consists of two independent folded regions at each end of the protein connected by a flexible unstructured region driving the protein to coexist as an ensemble of conformations. Limited proteolysis identified a 26 kDa globular domain at the C-terminus of the protein consisting of a mixture of α-helices and β-strands, as shown by circular dichroism (CD) and SAXS. In contrast, the N-terminal portion is mainly helical with an elongated shape. Sequence conservation suggests that this architecture is preserved amongst the different mycobacteria species, proposing specific roles for the N- and C-terminal domains assisted by the middle flexible linker.
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43
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Li X, Chen L, Liao J, Hui J, Li W, He ZG. A novel stress-inducible CmtR-ESX3-Zn 2+ regulatory pathway essential for survival of Mycobacterium bovis under oxidative stress. J Biol Chem 2020; 295:17083-17099. [PMID: 33033071 PMCID: PMC7863910 DOI: 10.1074/jbc.ra120.013017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 09/28/2020] [Indexed: 11/06/2022] Open
Abstract
Reactive oxygen species (ROS) are an unavoidable host environmental cue for intracellular pathogens such as Mycobacterium tuberculosis and Mycobacterium bovis; however, the signaling pathway in mycobacteria for sensing and responding to environmental stress remains largely unclear. Here, we characterize a novel CmtR-Zur-ESX3-Zn2+ regulatory pathway in M. bovis that aids mycobacterial survival under oxidative stress. We demonstrate that CmtR functions as a novel redox sensor and that its expression can be significantly induced under H2O2 stress. CmtR can physically interact with the negative regulator Zur and de-represses the expression of the esx-3 operon, which leads to Zn2+ accumulation and promotion of reactive oxygen species detoxication in mycobacterial cells. Zn2+ can also act as an effector molecule of the CmtR regulator, using which the latter can de-repress its own expression for further inducing bacterial antioxidant adaptation. Consistently, CmtR can induce the expression of EsxH, a component of esx-3 operon involved in Zn2+ transportation that has been reported earlier, and inhibit phagosome maturation in macrophages. Lastly, CmtR significantly contributes to bacterial survival in macrophages and in the lungs of infected mice. Our findings reveal the existence of an antioxidant regulatory pathway in mycobacteria and provide novel information on stress-triggered gene regulation and its association with host-pathogen interaction.
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Affiliation(s)
- Xiaohui Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Liu Chen
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jingjing Liao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jiechen Hui
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Weihui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Zheng-Guo He
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China.
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44
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Modeling Tubercular ESX-1 Secretion Using Mycobacterium marinum. Microbiol Mol Biol Rev 2020; 84:84/4/e00082-19. [DOI: 10.1128/mmbr.00082-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pathogenic mycobacteria cause chronic and acute diseases ranging from human tuberculosis (TB) to nontubercular infections.
Mycobacterium tuberculosis
causes both acute and chronic human tuberculosis. Environmentally acquired nontubercular mycobacteria (NTM) cause chronic disease in humans and animals. Not surprisingly, NTM and
M. tuberculosis
often use shared molecular mechanisms to survive within the host. The ESX-1 system is a specialized secretion system that is essential for virulence and is functionally conserved between
M. tuberculosis
and
Mycobacterium marinum
.
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45
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Conserved ESX-1 Substrates EspE and EspF Are Virulence Factors That Regulate Gene Expression. Infect Immun 2020; 88:IAI.00289-20. [PMID: 32900815 DOI: 10.1128/iai.00289-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/28/2020] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium tuberculosis, the cause of human tuberculosis, and Mycobacterium marinum, a nontubercular pathogen with a broad host range, require the ESX-1 secretion system for virulence. The ESX-1 system secretes proteins which cause phagosomal lysis within the macrophage via an unknown mechanism. As reported elsewhere (R. E. Bosserman et al., Proc Natl Acad Sci U S A 114:E10772-E10781, 2017, https://doi.org/10.1073/pnas.1710167114), we recently discovered that the ESX-1 system regulates gene expression in M. marinum This finding was confirmed in M. tuberculosis in reports by C. Sala et al. (PLoS Pathog 14:e1007491, 2018, https://doi.org/10.1371/journal.ppat.1007491) and A. M. Abdallah et al. (PLoS One 14:e0211003, 2019, https://doi.org/10.1371/journal.pone.0211003). We further demonstrated that a feedback control mechanism connects protein secretion to WhiB6-dependent expression of the esx-1 genes via an unknown mechanism. Here, we connect protein secretion and gene expression by showing for the first time that specific ESX-1 substrates have dual functions inside and outside the mycobacterial cell. We demonstrate that the EspE and EspF substrates negatively control esx-1 gene expression in the M. marinum cytoplasm through the conserved WhiB6 transcription factor. We found that EspE and EspF are required for virulence and promote lytic activity independently of the major EsxA and EsxB substrates. We show that the dual functions of EspE and EspF are conserved in the orthologous proteins from M. tuberculosis Our findings support a role for EspE and EspF in virulence that is independent of the EsxA and EsxB substrates and demonstrate that ESX-1 substrates have a conserved role in regulating gene expression.
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46
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Roy S, Ghatak D, Das P, BoseDasgupta S. ESX secretion system: The gatekeepers of mycobacterial survivability and pathogenesis. Eur J Microbiol Immunol (Bp) 2020; 10:202-209. [PMID: 33174865 PMCID: PMC7753977 DOI: 10.1556/1886.2020.00028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 09/25/2020] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium tuberculosis, the causative agent of Tuberculosis has plagued humankind for ages and has surfaced stronger than ever with the advent of drug resistance. Mycobacteria are adept at evading the host immune system and establishing infection by engaging host factors and secreting several virulence factors. Hence these secretion systems play a key role in mycobacterial pathogenesis. The type VII secretion system or ESX (early secretory antigenic target (ESAT6) secretion) system is one such crucial system that comprises five different pathways having distinct roles in mycobacterial proliferation, pathogenesis, cytosolic escape within macrophages, regulation of macrophage apoptosis, metal ion homeostasis, etc. ESX 1–5 systems are implicated in the secretion of a plethora of proteins, of which only a few are functionally characterized. Here we summarize the current knowledge of ESX secretion systems of mycobacteria with a special focus on ESX-1 and ESX-5 systems that subvert macrophage defenses and help mycobacteria to establish their niche within the macrophage.
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Affiliation(s)
- Sadhana Roy
- Department of Biotechnology, Molecular Immunology and Cellular Microbiology Laboratory, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Debika Ghatak
- Department of Biotechnology, Molecular Immunology and Cellular Microbiology Laboratory, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Payel Das
- Department of Biotechnology, Molecular Immunology and Cellular Microbiology Laboratory, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Somdeb BoseDasgupta
- Department of Biotechnology, Molecular Immunology and Cellular Microbiology Laboratory, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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Bunduc CM, Bitter W, Houben E. Structure and Function of the Mycobacterial Type VII Secretion Systems. Annu Rev Microbiol 2020; 74:315-335. [DOI: 10.1146/annurev-micro-012420-081657] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bacteria have evolved intricate secretion machineries for the successful delivery of large molecules across their cell envelopes. Such specialized secretion systems allow a variety of bacteria to thrive in specific host environments. In mycobacteria, type VII secretion systems (T7SSs) are dedicated protein transport machineries that fulfill diverse and crucial roles, ranging from metabolite uptake to immune evasion and subversion to conjugation. Since the discovery of mycobacterial T7SSs about 15 y ago, genetic, structural, and functional studies have provided insight into the roles and functioning of these secretion machineries. Here, we focus on recent advances in the elucidation of the structure and mechanism of mycobacterial T7SSs in protein secretion. As many of these systems are essential for mycobacterial growth or virulence, they provide opportunities for the development of novel therapies to combat a number of relevant mycobacterial diseases.
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Affiliation(s)
- Catalin M. Bunduc
- Section of Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HZ Amsterdam, The Netherlands
| | - W. Bitter
- Section of Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HZ Amsterdam, The Netherlands
- Department of Medical Microbiology and Infection Control, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Centers, 1007 MB Amsterdam, The Netherlands
| | - E.N.G. Houben
- Section of Molecular Microbiology, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HZ Amsterdam, The Netherlands
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48
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Patil S, Palande A, Lodhiya T, Pandit A, Mukherjee R. Redefining genetic essentiality in Mycobacterium tuberculosis. Gene 2020; 765:145091. [PMID: 32898604 DOI: 10.1016/j.gene.2020.145091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 08/18/2020] [Accepted: 08/21/2020] [Indexed: 11/15/2022]
Abstract
Sequencing transposon mutant libraries have been pivotal in annotating essential and non-essential genes in bacteria. This is particularly very helpful in the case of Mycobacterium tuberculosis with a large part of its genome without known function. It is not known whether there are any variations in the essentiality states as a function of optimal growth in the absence of any selection pressure. We here grow a high-density mutant library of M. tuberculosis through serial cultures and monitor the temporal fluctuations in insertion frequencies across all TA dinucleotides in the genome. Genes that cause morphological and physiological heterogeneity or enable metabolic bypass were found to gradually lose insertions, while genes comprising the toxin-antitoxin systems were found to get enriched with insertions during growth in nutrient replete conditions. High levels of fluctuations were observed in genes involved in cell wall and cell processes, intermediary metabolism, and genes involved in virulence, suggesting new modes of adaptation undertaken by the mutants. We also report the essentiality status of several newly annotated genetic features.
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Affiliation(s)
- Saniya Patil
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, India
| | - Aseem Palande
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, India
| | - Tejan Lodhiya
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, India
| | - Awadhesh Pandit
- National Center for Biological Sciences, Bengaluru 560065, India
| | - Raju Mukherjee
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, India.
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49
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Williamson ZA, Chaton CT, Ciocca WA, Korotkova N, Korotkov KV. PE5-PPE4-EspG 3 heterotrimer structure from mycobacterial ESX-3 secretion system gives insight into cognate substrate recognition by ESX systems. J Biol Chem 2020; 295:12706-12715. [PMID: 32675282 PMCID: PMC7476729 DOI: 10.1074/jbc.ra120.012698] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 07/06/2020] [Indexed: 01/05/2023] Open
Abstract
Mycobacterium tuberculosis has evolved numerous type VII secretion (ESX) systems to secrete multiple factors important for both growth and virulence across their cell envelope. ESX-1, ESX-3, and ESX-5 systems have been shown to each secrete a distinct set of substrates, including PE and PPE families of proteins, named for conserved Pro-Glu and Pro-Pro-Glu motifs in their N termini. Proper secretion of the PE-PPE proteins requires the presence of EspG, with each system encoding its own unique copy. There is no cross-talk between any of the ESX systems, and how each EspG recognizes its subset of PE-PPE proteins is currently unknown. The only current structural characterization of PE-PPE-EspG heterotrimers is from the ESX-5 system. Here we present the crystal structure of the PE5mt-PPE4mt-EspG3mm heterotrimer from the ESX-3 system. Our heterotrimer reveals that EspG3mm interacts exclusively with PPE4mt in a similar manner to EspG5, shielding the hydrophobic tip of PPE4mt from solvent. The C-terminal helical domain of EspG3mm is dynamic, alternating between "open" and "closed" forms, and this movement is likely functionally relevant in the unloading of PE-PPE heterodimers at the secretion machinery. In contrast to the previously solved ESX-5 heterotrimers, the PE-PPE heterodimer of our ESX-3 heterotrimer is interacting with its chaperone at a drastically different angle and presents different faces of the PPE protein to the chaperone. We conclude that the PPE-EspG interface from each ESX system has a unique shape complementarity that allows each EspG to discriminate among noncognate PE-PPE pairs.
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Affiliation(s)
- Zachary A Williamson
- Department of Molecular & Cellular Biochemistry and the Center for Structural Biology, University of Kentucky, Lexington, Kentucky, USA
| | - Catherine T Chaton
- Department of Molecular & Cellular Biochemistry and the Center for Structural Biology, University of Kentucky, Lexington, Kentucky, USA
| | - William A Ciocca
- Department of Molecular & Cellular Biochemistry and the Center for Structural Biology, University of Kentucky, Lexington, Kentucky, USA
| | - Natalia Korotkova
- Department of Molecular & Cellular Biochemistry and the Center for Structural Biology, University of Kentucky, Lexington, Kentucky, USA
| | - Konstantin V Korotkov
- Department of Molecular & Cellular Biochemistry and the Center for Structural Biology, University of Kentucky, Lexington, Kentucky, USA
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50
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Piton J, Pojer F, Wakatsuki S, Gati C, Cole ST. High resolution CryoEM structure of the ring-shaped virulence factor EspB from Mycobacterium tuberculosis. J Struct Biol X 2020; 4:100029. [PMID: 32875288 PMCID: PMC7451430 DOI: 10.1016/j.yjsbx.2020.100029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/11/2020] [Accepted: 06/28/2020] [Indexed: 12/23/2022] Open
Abstract
The EspB protein of Mycobacterium tuberculosis is a 60 kDa virulence factor, implicated in conjugation and exported by the ESX-1 system of which it may also be a component. Previous attempts to obtain high-resolution maps of EspB by cryo-electron microscopic examination of single particles have been thwarted by severe orientation bias of the particles. This was overcome by using detergent as a surfactant thereby allowing reconstruction of the EspB structure at 3.37 Å resolution. The final structure revealed the N-terminal domain of EspB to be organized as a cylindrical heptamer with dimensions of 90 Å x 90 Å and a central channel of 45 Å diameter whereas the C-terminal domain was unstructured. New atomic insight was obtained into the helical packing required for protomer interactions and the overall electrostatic potential. The external surface is electronegatively charged while the channel is lined with electropositive patches. EspB thus has many features of a pore-like transport protein that might allow the passage of an ESX-1 substrate such as the 35 Å diameter EsxA-EsxB heterodimer or B-form DNA consistent with its proposed role in DNA uptake.
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Affiliation(s)
- Jérémie Piton
- Global Health Institute, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Florence Pojer
- Protein Production and Structure Core Facility, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Soichi Wakatsuki
- Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Cornelius Gati
- Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Structural Biology, Stanford University, Palo Alto, CA 94305, USA
| | - Stewart T. Cole
- Global Health Institute, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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