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Mulholland CV, Wiggins TJ, Cui J, Vilchèze C, Rajagopalan S, Shultis MW, Reyes-Fernández EZ, Jacobs WR, Berney M. Propionate prevents loss of the PDIM virulence lipid in Mycobacterium tuberculosis. Nat Microbiol 2024; 9:1607-1618. [PMID: 38740932 DOI: 10.1038/s41564-024-01697-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 04/04/2024] [Indexed: 05/16/2024]
Abstract
Phthiocerol dimycocerosate (PDIM) is an essential virulence lipid of Mycobacterium tuberculosis. In vitro culturing rapidly selects for spontaneous PDIM-negative mutants that have attenuated virulence and increased cell wall permeability, thus impacting the relevance of experimental findings. PDIM loss can also reduce the efficacy of the BCG Pasteur vaccine. Here we show that vancomycin susceptibility can rapidly screen for M. tuberculosis PDIM production. We find that metabolic deficiency of methylmalonyl-CoA impedes the growth of PDIM-producing bacilli, selecting for PDIM-negative variants. Supplementation with odd-chain fatty acids, cholesterol or vitamin B12 restores PDIM-positive bacterial growth. Specifically, we show that propionate supplementation enhances PDIM-producing bacterial growth and selects against PDIM-negative mutants, analogous to in vivo conditions. Our study provides a simple approach to screen for and maintain PDIM production, and reveals how discrepancies between the host and in vitro nutrient environments can attenuate bacterial pathogenicity.
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Affiliation(s)
- Claire V Mulholland
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Thomas J Wiggins
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Jinhua Cui
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Catherine Vilchèze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Saranathan Rajagopalan
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Michael W Shultis
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | | | - William R Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA.
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2
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Bracha Y, Barkan D. A simplified and efficient method for single-step, targeted gene deletion in mycobacteria. Tuberculosis (Edinb) 2024; 147:102520. [PMID: 38781657 DOI: 10.1016/j.tube.2024.102520] [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: 03/10/2024] [Revised: 05/12/2024] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
Targeted gene deletion in mycobacteria remain complicated, requiring expertise and multiple steps. Here we present a single-step, easy to understand and perform method for targeted gene deletion. Using this method, we successfully deleted several genes in both M. smegmatis and M. abscessus. We believe this method will facilitate molecular research of mycobacteria and make it accessible to a greater number of researchers throughout the world.
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Affiliation(s)
- Yahav Bracha
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Daniel Barkan
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
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3
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Peng C, Cheng Y, Ma M, Chen Q, Duan Y, Liu S, Cheng H, Yang H, Huang J, Bu W, Shi C, Wu X, Chen J, Zheng R, Liu Z, Ji Z, Wang J, Huang X, Wang P, Sha W, Ge B, Wang L. Mycobacterium tuberculosis suppresses host antimicrobial peptides by dehydrogenating L-alanine. Nat Commun 2024; 15:4216. [PMID: 38760394 PMCID: PMC11101664 DOI: 10.1038/s41467-024-48588-4] [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: 09/18/2023] [Accepted: 05/07/2024] [Indexed: 05/19/2024] Open
Abstract
Antimicrobial peptides (AMPs), ancient scavengers of bacteria, are very poorly induced in macrophages infected by Mycobacterium tuberculosis (M. tuberculosis), but the underlying mechanism remains unknown. Here, we report that L-alanine interacts with PRSS1 and unfreezes the inhibitory effect of PRSS1 on the activation of NF-κB pathway to induce the expression of AMPs, but mycobacterial alanine dehydrogenase (Ald) Rv2780 hydrolyzes L-alanine and reduces the level of L-alanine in macrophages, thereby suppressing the expression of AMPs to facilitate survival of mycobacteria. Mechanistically, PRSS1 associates with TAK1 and disruptes the formation of TAK1/TAB1 complex to inhibit TAK1-mediated activation of NF-κB pathway, but interaction of L-alanine with PRSS1, disables PRSS1-mediated impairment on TAK1/TAB1 complex formation, thereby triggering the activation of NF-κB pathway to induce expression of AMPs. Moreover, deletion of antimicrobial peptide gene β-defensin 4 (Defb4) impairs the virulence by Rv2780 during infection in mice. Both L-alanine and the Rv2780 inhibitor, GWP-042, exhibits excellent inhibitory activity against M. tuberculosis infection in vivo. Our findings identify a previously unrecognized mechanism that M. tuberculosis uses its own alanine dehydrogenase to suppress host immunity, and provide insights relevant to the development of effective immunomodulators that target M. tuberculosis.
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Affiliation(s)
- Cheng Peng
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Yuanna Cheng
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Mingtong Ma
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Qiu Chen
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Yongjia Duan
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Shanshan Liu
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Hongyu Cheng
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Hua Yang
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jingping Huang
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Wenyi Bu
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Chenyue Shi
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Xiangyang Wu
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Clinical Translation Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jianxia Chen
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Clinical Translation Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ruijuan Zheng
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhonghua Liu
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhe Ji
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China
| | - Jie Wang
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaochen Huang
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Peng Wang
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wei Sha
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Baoxue Ge
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China.
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
- Clinical Translation Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
| | - Lin Wang
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, China.
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
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4
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Bauman AA, Sarathy JP, Kaya F, Massoudi LM, Scherman MS, Hastings C, Liu J, Xie M, Brooks EJ, Ramey ME, Jones IL, Benedict ND, Maclaughlin MR, Miller-Dawson JA, Waidyarachchi SL, Butler MM, Bowlin TL, Zimmerman MD, Lenaerts AJ, Meibohm B, Gonzalez-Juarrero M, Lyons MA, Dartois V, Lee RE, Robertson GT. Spectinamide MBX-4888A exhibits favorable lesion and tissue distribution and promotes treatment shortening in advanced murine models of tuberculosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.593953. [PMID: 38798577 PMCID: PMC11118289 DOI: 10.1101/2024.05.13.593953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The spectinamides are novel, narrow-spectrum semisynthetic analogs of spectinomycin, modified to avoid intrinsic efflux by Mycobacterium tuberculosis . Spectinamides, including lead MBX-4888A (Lee-1810), exhibit promising therapeutic profiles in mice, as single drugs and as partner agents with other anti-tuberculosis antibiotics including rifampin and/or pyrazinamide. To demonstrate that this translates to more effective cure, we first confirmed the role of rifampin, with or without pyrazinamide, as essential to achieve effective bactericidal responses and sterilizing cure in the current standard of care regimen in chronically infected C3HeB/FeJ mice compared to BALB/c mice. Thus, demonstrating added value in testing clinically relevant regimens in murine models of increasing pathologic complexity. Next we show that MBX-4888A, given by injection with the front-line standard of care regimen, is treatment shortening in multiple murine tuberculosis infection models. The positive treatment responses to MBX-4888A combination therapy in multiple mouse models including mice exhibiting advanced pulmonary disease can be attributed to favorable distribution in tissues and lesions, retention in caseum, along with favorable effects with rifampin and pyrazinamide under conditions achieved in necrotic lesions. This study also provides an additional data point regarding the safety and tolerability of spectinamide MBX-4888A in long-term murine efficacy studies.
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5
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Zang X, Zhang J, Jiang Y, Feng T, Cui Y, Wang H, Cui Z, Dang G, Liu S. Serine protease Rv2569c facilitates transmission of Mycobacterium tuberculosis via disrupting the epithelial barrier by cleaving E-cadherin. PLoS Pathog 2024; 20:e1012214. [PMID: 38722857 PMCID: PMC11081392 DOI: 10.1371/journal.ppat.1012214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
Epithelial cells function as the primary line of defense against invading pathogens. However, bacterial pathogens possess the ability to compromise this barrier and facilitate the transmigration of bacteria. Nonetheless, the specific molecular mechanism employed by Mycobacterium tuberculosis (M.tb) in this process is not fully understood. Here, we investigated the role of Rv2569c in M.tb translocation by assessing its ability to cleave E-cadherin, a crucial component of cell-cell adhesion junctions that are disrupted during bacterial invasion. By utilizing recombinant Rv2569c expressed in Escherichia coli and subsequently purified through affinity chromatography, we demonstrated that Rv2569c exhibited cell wall-associated serine protease activity. Furthermore, Rv2569c was capable of degrading a range of protein substrates, including casein, fibrinogen, fibronectin, and E-cadherin. We also determined that the optimal conditions for the protease activity of Rv2569c occurred at a temperature of 37°C and a pH of 9.0, in the presence of MgCl2. To investigate the function of Rv2569c in M.tb, a deletion mutant of Rv2569c and its complemented strains were generated and used to infect A549 cells and mice. The results of the A549-cell infection experiments revealed that Rv2569c had the ability to cleave E-cadherin and facilitate the transmigration of M.tb through polarized A549 epithelial cell layers. Furthermore, in vivo infection assays demonstrated that Rv2569c could disrupt E-cadherin, enhance the colonization of M.tb, and induce pathological damage in the lungs of C57BL/6 mice. Collectively, these results strongly suggest that M.tb employs the serine protease Rv2569c to disrupt epithelial defenses and facilitate its systemic dissemination by crossing the epithelial barrier.
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Affiliation(s)
- Xinxin Zang
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
| | - Jiajun Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
| | - Yanyan Jiang
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
| | - Tingting Feng
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
| | - Yingying Cui
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
| | - Hui Wang
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
| | - Ziyin Cui
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
| | - Guanghui Dang
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
| | - Siguo Liu
- State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China
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6
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Adolph C, Cheung CY, McNeil MB, Jowsey WJ, Williams ZC, Hards K, Harold LK, Aboelela A, Bujaroski RS, Buckley BJ, Tyndall JDA, Li Z, Langer JD, Preiss L, Meier T, Steyn AJC, Rhee KY, Berney M, Kelso MJ, Cook GM. A dual-targeting succinate dehydrogenase and F 1F o-ATP synthase inhibitor rapidly sterilizes replicating and non-replicating Mycobacterium tuberculosis. Cell Chem Biol 2024; 31:683-698.e7. [PMID: 38151019 DOI: 10.1016/j.chembiol.2023.12.002] [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: 05/08/2023] [Revised: 09/13/2023] [Accepted: 12/04/2023] [Indexed: 12/29/2023]
Abstract
Mycobacterial bioenergetics is a validated target space for antitubercular drug development. Here, we identify BB2-50F, a 6-substituted 5-(N,N-hexamethylene)amiloride derivative as a potent, multi-targeting bioenergetic inhibitor of Mycobacterium tuberculosis. We show that BB2-50F rapidly sterilizes both replicating and non-replicating cultures of M. tuberculosis and synergizes with several tuberculosis drugs. Target identification experiments, supported by docking studies, showed that BB2-50F targets the membrane-embedded c-ring of the F1Fo-ATP synthase and the catalytic subunit (substrate-binding site) of succinate dehydrogenase. Biochemical assays and metabolomic profiling showed that BB2-50F inhibits succinate oxidation, decreases the activity of the tricarboxylic acid (TCA) cycle, and results in succinate secretion from M. tuberculosis. Moreover, we show that the lethality of BB2-50F under aerobic conditions involves the accumulation of reactive oxygen species. Overall, this study identifies BB2-50F as an effective inhibitor of M. tuberculosis and highlights that targeting multiple components of the mycobacterial respiratory chain can produce fast-acting antimicrobials.
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Affiliation(s)
- Cara Adolph
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Matthew B McNeil
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - William J Jowsey
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - Zoe C Williams
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Kiel Hards
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Liam K Harold
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Ashraf Aboelela
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Richard S Bujaroski
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Benjamin J Buckley
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Joel D A Tyndall
- School of Pharmacy, University of Otago, Dunedin 9054, New Zealand
| | - Zhengqiu Li
- School of Pharmacy, Jinan University, Guangzhou, China
| | - Julian D Langer
- Proteomics, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Laura Preiss
- Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Thomas Meier
- Department of Life Sciences, Imperial College London, Exhibition Road, London SW7 2AZ, UK; Private University in the Principality of Liechtenstein, Triesen, Liechtenstein
| | - Adrie J C Steyn
- Africa Health Research Institute, University of KwaZulu Natal, Durban, KwaZulu, Natal, South Africa; Department of Microbiology, Centers for AIDs Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kyu Y Rhee
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY 14853, USA; Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Michael J Kelso
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Gregory M Cook
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand.
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7
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Schneider RF, Hallstrom K, DeMott C, McDonough KA. Conditional protein splicing of the Mycobacterium tuberculosis RecA intein in its native host. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.15.589443. [PMID: 38659745 PMCID: PMC11042385 DOI: 10.1101/2024.04.15.589443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The recA gene, encoding Recombinase A (RecA) is one of three Mycobacterium tuberculosis (Mtb) genes encoding an in-frame intervening protein sequence (intein) that must splice out of precursor host protein to produce functional protein. Ongoing debate about whether inteins function solely as selfish genetic elements or benefit their host cells requires understanding of interplay between inteins and their hosts. We measured environmental effects on native RecA intein splicing within Mtb using a combination of western blots and promoter reporter assays. RecA splicing was stimulated in bacteria exposed to DNA damaging agents or by treatment with copper in hypoxic, but not normoxic, conditions. Spliced RecA was processed by the Mtb proteasome, while free intein was degraded efficiently by other unknown mechanisms. Unspliced precursor protein was not observed within Mtb despite its accumulation during ectopic expression of Mtb recA within E. coli. Surprisingly, Mtb produced free N-extein in some conditions, and ectopic expression of Mtb N-extein activated LexA in E. coli. These results demonstrate that the bacterial environment greatly impacts RecA splicing in Mtb, underscoring the importance of studying intein splicing in native host environments and raising the exciting possibility of intein splicing as a novel regulatory mechanism in Mtb.
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Affiliation(s)
- Ryan F. Schneider
- Biomedical Sciences Department, School of Public Health, State University of New York at Albany
| | | | | | - Kathleen A. McDonough
- Biomedical Sciences Department, School of Public Health, State University of New York at Albany
- Wadsworth Center, New York Department of Health
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8
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Ju X, Li S, Froom R, Wang L, Lilic M, Delbeau M, Campbell EA, Rock JM, Liu S. Incomplete transcripts dominate the Mycobacterium tuberculosis transcriptome. Nature 2024; 627:424-430. [PMID: 38418874 PMCID: PMC10937400 DOI: 10.1038/s41586-024-07105-9] [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: 11/14/2022] [Accepted: 01/23/2024] [Indexed: 03/02/2024]
Abstract
Mycobacterium tuberculosis (Mtb) is a bacterial pathogen that causes tuberculosis (TB), an infectious disease that is responsible for major health and economic costs worldwide1. Mtb encounters diverse environments during its life cycle and responds to these changes largely by reprogramming its transcriptional output2. However, the mechanisms of Mtb transcription and how they are regulated remain poorly understood. Here we use a sequencing method that simultaneously determines both termini of individual RNA molecules in bacterial cells3 to profile the Mtb transcriptome at high resolution. Unexpectedly, we find that most Mtb transcripts are incomplete, with their 5' ends aligned at transcription start sites and 3' ends located 200-500 nucleotides downstream. We show that these short RNAs are mainly associated with paused RNA polymerases (RNAPs) rather than being products of premature termination. We further show that the high propensity of Mtb RNAP to pause early in transcription relies on the binding of the σ-factor. Finally, we show that a translating ribosome promotes transcription elongation, revealing a potential role for transcription-translation coupling in controlling Mtb gene expression. In sum, our findings depict a mycobacterial transcriptome that prominently features incomplete transcripts resulting from RNAP pausing. We propose that the pausing phase constitutes an important transcriptional checkpoint in Mtb that allows the bacterium to adapt to environmental changes and could be exploited for TB therapeutics.
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Affiliation(s)
- Xiangwu Ju
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Shuqi Li
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Ruby Froom
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Ling Wang
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Mirjana Lilic
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Madeleine Delbeau
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Jeremy M Rock
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA.
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA.
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9
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Bhargavi G, Mallakuntla MK, Kale D, Tiwari S. Rv0687 a Putative Short-Chain Dehydrogenase is indispensable for pathogenesis of Mycobacterium tuberculosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.12.571312. [PMID: 38168250 PMCID: PMC10760034 DOI: 10.1101/2023.12.12.571312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Mycobacterium tuberculosis (Mtb), a successful human pathogen, resides in host sentinel cells and combats the stressful intracellular environment induced by reactive oxygen and nitrogen species during infection. Mtb employs several evasion mechanisms in the face of the host as a survival strategy, including detoxifying enzymes as short-chain dehydrogenases/ reductases (SDRs) to withstand host-generated insults. In this study, using specialized transduction we have generated a Rv0687 deletion mutant and its complemented strain and investigated the functional role of Rv0687, a member of SDRs family genes in Mtb pathogenesis. Wildtype (WT) and mutant Mtb strain lacking Rv0687 (RvΔ0687) were tested for in-vitro stress response and in-vivo survival in macrophages and mice models of infection. The study demonstrates that Rv0687 is crucial for sustaining bacterial growth in nutrition-limited conditions. The deletion of Rv0687 elevated the sensitivity of Mtb to oxidative and nitrosative stress-inducing agents. Furthermore, the lack of Rv0687 compromised the survival of Mtb in primary bone marrow macrophages and led to an increase in the levels of the secreted proinflammatory cytokines TNF-α, and MIP-1α. Interestingly, the growth of WT and RvΔ0687 was similar in the lungs of infected immunocompromised mice however, a significant reduction in RvΔ0687 growth was observed in the spleen of immunocompromised Rag -/- mice at 4 weeks post-infection. Moreover Rag -/- mice infected with RvΔ0687 survived longer compared to WT Mtb strain. Additionally, we observed significant reduction in bacterial burden in spleens and lungs of immunocompetent C57BL/6 mice infected with RvΔ0687 compared to complemented and WT Mtb strains. Collectively, this study reveals that Rv0687 plays a role in Mtb pathogenesis.
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10
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Malakar B, Chauhan K, Sanyal P, Naz S, Kalam H, Vivek-Ananth RP, Singh LV, Samal A, Kumar D, Nandicoori VK. Phosphorylation of CFP10 modulates Mycobacterium tuberculosis virulence. mBio 2023; 14:e0123223. [PMID: 37791794 PMCID: PMC10653824 DOI: 10.1128/mbio.01232-23] [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: 05/18/2023] [Accepted: 07/25/2023] [Indexed: 10/05/2023] Open
Abstract
IMPORTANCE Secreted virulence factors play a critical role in bacterial pathogenesis. Virulence effectors not only help bacteria to overcome the host immune system but also aid in establishing infection. Mtb, which causes tuberculosis in humans, encodes various virulence effectors. Triggers that modulate the secretion of virulence effectors in Mtb are yet to be fully understood. To gain mechanistic insight into the secretion of virulence effectors, we performed high-throughput proteomic studies. With the help of system-level protein-protein interaction network analysis and empirical validations, we unravelled a link between phosphorylation and secretion. Taking the example of the well-known virulence factor of CFP10, we show that the dynamics of CFP10 phosphorylation strongly influenced bacterial virulence and survival ex vivo and in vivo. This study presents the role of phosphorylation in modulating the secretion of virulence factors.
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Affiliation(s)
- Basanti Malakar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
| | - Komal Chauhan
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - Priyadarshini Sanyal
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Centre for Cellular and Molecular Biology Campus, Hyderabad, India
| | - Saba Naz
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
| | - Haroon Kalam
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - R. P. Vivek-Ananth
- The Institute of Mathematical Sciences (IMSc), Homi Bhabha National Institute (HBNI), Chennai, India
| | - Lakshya Veer Singh
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - Areejit Samal
- The Institute of Mathematical Sciences (IMSc), Homi Bhabha National Institute (HBNI), Chennai, India
| | - Dhiraj Kumar
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - Vinay Kumar Nandicoori
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Centre for Cellular and Molecular Biology Campus, Hyderabad, India
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11
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Mulholland CV, Wiggins TJ, Cui J, Vilchèze C, Rajagopalan S, Shultis MW, Reyes-Fernández EZ, Jacobs WR, Berney M. The PDIM paradox of Mycobacterium tuberculosis: new solutions to a persistent problem. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562559. [PMID: 37905120 PMCID: PMC10614861 DOI: 10.1101/2023.10.16.562559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Phthiocerol dimycocerosate (PDIM) is an essential virulence lipid of Mycobacterium tuberculosis. In vitro culturing rapidly selects for spontaneous mutations that cause PDIM loss leading to virulence attenuation and increased cell wall permeability. We discovered that PDIM loss is due to a metabolic deficiency of methylmalonyl-CoA that impedes the growth of PDIM-producing bacilli. This can be remedied by supplementation with odd-chain fatty acids, cholesterol, or vitamin B12. We developed a much-needed facile and scalable routine assay for PDIM production and show that propionate supplementation enhances the growth of PDIM-producing bacilli and selects against PDIM-negative mutants, analogous to in vivo conditions. Our results solve a major issue in tuberculosis research and exemplify how discrepancies between the host and in vitro nutrient environments can attenuate bacterial pathogenicity.
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Affiliation(s)
- Claire V. Mulholland
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | | | | | - Catherine Vilchèze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | - Saranathan Rajagopalan
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | - Michael W. Shultis
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | | | - William R. Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine,
Bronx, New York, USA
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12
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Ji L, Jiang T, Zhao X, Cai D, Hua K, Du P, Chen Y, Xie J. Mycobacterium tuberculosis Rv0494 Protein Contributes to Mycobacterial Persistence. Infect Drug Resist 2023; 16:4755-4762. [PMID: 37501888 PMCID: PMC10370413 DOI: 10.2147/idr.s419914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 07/14/2023] [Indexed: 07/29/2023] Open
Abstract
Purpose Fatty acid metabolism plays an important role in the survival and pathogenesis of Mycobacterium tuberculosis. During dormancy, lipids are considered to be the main source of energy. A previous study found that Rv0494 is a starvation-inducible, lipid-responsive transcriptional regulator. However, the role of Rv0494 in bacterial persister survival has not been studied. Methods We constructed a Rv0494 deletion mutant strain of Mycobacterium tuberculosis H37Rv and evaluated the susceptibility of the mutant strain to antibiotics using a persistence test. Results We found that mutations in Rv0494 lead to survival defects of persisters, which reflected in increased sensitivity to isoniazid. Conclusion We conclude that Rv0494 is important for persister survival and may serve as a good target for developing new antibiotics that kill persister bacteria for improved treatment of persistent bacterial infections.
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Affiliation(s)
- Lei Ji
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, People’s Republic of China
| | - Tingting Jiang
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, People’s Republic of China
| | - Xin Zhao
- Department of International Registration, Ustar Biotechnologies (Hangzhou) Ltd, Hangzhou, Zhejiang, People’s Republic of China
| | - Damin Cai
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, People’s Republic of China
| | - Kouzhen Hua
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, People’s Republic of China
| | - Peng Du
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, People’s Republic of China
| | - Yuanyuan Chen
- Tuberculosis Diagnosis and Treatment Center, Hangzhou Red Cross Hospital, Hangzhou, Zhejiang, People’s Republic of China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Chongqing, People’s Republic of China
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13
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Grigg JC, Copp JN, Krekhno JMC, Liu J, Ibrahimova A, Eltis LD. Deciphering the biosynthesis of a novel lipid in Mycobacterium tuberculosis expands the known roles of the nitroreductase superfamily. J Biol Chem 2023; 299:104924. [PMID: 37328106 PMCID: PMC10404671 DOI: 10.1016/j.jbc.2023.104924] [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: 04/27/2023] [Revised: 05/29/2023] [Accepted: 06/06/2023] [Indexed: 06/18/2023] Open
Abstract
Mycobacterium tuberculosis's (Mtb) success as a pathogen is due in part to its sophisticated lipid metabolic programs, both catabolic and biosynthetic. Several of Mtb lipids have specific roles in pathogenesis, but the identity and roles of many are unknown. Here, we demonstrated that the tyz gene cluster in Mtb, previously implicated in resistance to oxidative stress and survival in macrophages, encodes the biosynthesis of acyl-oxazolones. Heterologous expression of tyzA (Rv2336), tyzB (Rv2338c) and tyzC (Rv2337c) resulted in the biosynthesis of C12:0-tyrazolone as the predominant compound, and the C12:0-tyrazolone was identified in Mtb lipid extracts. TyzA catalyzed the N-acylation of l-amino acids, with highest specificity for l-Tyr and l-Phe and lauroyl-CoA (kcat/KM = 5.9 ± 0.8 × 103 M-1s-1). In cell extracts, TyzC, a flavin-dependent oxidase (FDO) of the nitroreductase (NTR) superfamily, catalyzed the O2-dependent desaturation of the N-acyl-L-Tyr produced by TyzA, while TyzB, a ThiF homolog, catalyzed its ATP-dependent cyclization. The substrate preference of TyzB and TyzC appear to determine the identity of the acyl-oxazolone. Phylogenetic analyses revealed that the NTR superfamily includes a large number of broadly distributed FDOs, including five in Mtb that likely catalyze the desaturation of lipid species. Finally, TCA1, a molecule with activity against drug-resistant and persistent tuberculosis, failed to inhibit the cyclization activity of TyzB, the proposed secondary target of TCA1. Overall, this study identifies a novel class of Mtb lipids, clarifies the role of a potential drug target, and expands our understanding of the NTR superfamily.
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Affiliation(s)
- Jason C Grigg
- Department of Microbiology & Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Janine N Copp
- Michael Smith Laboratories, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessica M C Krekhno
- Department of Microbiology & Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jie Liu
- Department of Microbiology & Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Aygun Ibrahimova
- Department of Microbiology & Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lindsay D Eltis
- Department of Microbiology & Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada.
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14
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Hoi DM, Junker S, Junk L, Schwechel K, Fischel K, Podlesainski D, Hawkins PME, van Geelen L, Kaschani F, Leodolter J, Morreale FE, Kleine S, Guha S, Rumpel K, Schmiedel VM, Weinstabl H, Meinhart A, Payne RJ, Kaiser M, Hartl M, Boehmelt G, Kazmaier U, Kalscheuer R, Clausen T. Clp-targeting BacPROTACs impair mycobacterial proteostasis and survival. Cell 2023; 186:2176-2192.e22. [PMID: 37137307 DOI: 10.1016/j.cell.2023.04.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 02/24/2023] [Accepted: 04/05/2023] [Indexed: 05/05/2023]
Abstract
The ClpC1:ClpP1P2 protease is a core component of the proteostasis system in mycobacteria. To improve the efficacy of antitubercular agents targeting the Clp protease, we characterized the mechanism of the antibiotics cyclomarin A and ecumicin. Quantitative proteomics revealed that the antibiotics cause massive proteome imbalances, including upregulation of two unannotated yet conserved stress response factors, ClpC2 and ClpC3. These proteins likely protect the Clp protease from excessive amounts of misfolded proteins or from cyclomarin A, which we show to mimic damaged proteins. To overcome the Clp security system, we developed a BacPROTAC that induces degradation of ClpC1 together with its ClpC2 caretaker. The dual Clp degrader, built from linked cyclomarin A heads, was highly efficient in killing pathogenic Mycobacterium tuberculosis, with >100-fold increased potency over the parent antibiotic. Together, our data reveal Clp scavenger proteins as important proteostasis safeguards and highlight the potential of BacPROTACs as future antibiotics.
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Affiliation(s)
- David M Hoi
- Research Institute of Molecular Pathology, Vienna BioCenter, 1030 Vienna, Austria; Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria; University of Vienna, Center for Molecular Biology, Department for Biochemistry and Cell Biology, 1030 Vienna, Austria
| | - Sabryna Junker
- Research Institute of Molecular Pathology, Vienna BioCenter, 1030 Vienna, Austria
| | - Lukas Junk
- Saarland University, Organic Chemistry I, 66123 Saarbrücken, Germany; Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany.
| | - Kristin Schwechel
- Institute of Pharmaceutical Biology and Biotechnology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | | | - David Podlesainski
- University of Duisburg-Essen, Center of Medical Biotechnology, Faculty of Biology, 45141 Essen, Germany
| | - Paige M E Hawkins
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia; Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, NSW 2006, Australia
| | - Lasse van Geelen
- Institute of Pharmaceutical Biology and Biotechnology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Farnusch Kaschani
- University of Duisburg-Essen, Center of Medical Biotechnology, Faculty of Biology, 45141 Essen, Germany
| | - Julia Leodolter
- Research Institute of Molecular Pathology, Vienna BioCenter, 1030 Vienna, Austria
| | | | - Stefan Kleine
- University of Duisburg-Essen, Center of Medical Biotechnology, Faculty of Biology, 45141 Essen, Germany
| | - Somraj Guha
- Saarland University, Organic Chemistry I, 66123 Saarbrücken, Germany
| | - Klaus Rumpel
- Boehringer Ingelheim RCV GmbH & Co KG, 1120 Vienna, Austria
| | | | | | - Anton Meinhart
- Research Institute of Molecular Pathology, Vienna BioCenter, 1030 Vienna, Austria
| | - Richard J Payne
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia; Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, NSW 2006, Australia
| | - Markus Kaiser
- University of Duisburg-Essen, Center of Medical Biotechnology, Faculty of Biology, 45141 Essen, Germany
| | - Markus Hartl
- Max Perutz Labs, Vienna BioCenter, 1030 Vienna, Austria; University of Vienna, Center for Molecular Biology, Department for Biochemistry and Cell Biology, 1030 Vienna, Austria
| | - Guido Boehmelt
- Boehringer Ingelheim RCV GmbH & Co KG, 1120 Vienna, Austria
| | - Uli Kazmaier
- Saarland University, Organic Chemistry I, 66123 Saarbrücken, Germany; Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
| | - Rainer Kalscheuer
- Institute of Pharmaceutical Biology and Biotechnology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Tim Clausen
- Research Institute of Molecular Pathology, Vienna BioCenter, 1030 Vienna, Austria; Medical University of Vienna, 1030 Vienna, Austria.
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15
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Waller NJE, Cheung CY, Cook GM, McNeil MB. The evolution of antibiotic resistance is associated with collateral drug phenotypes in Mycobacterium tuberculosis. Nat Commun 2023; 14:1517. [PMID: 36934122 PMCID: PMC10024696 DOI: 10.1038/s41467-023-37184-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 03/06/2023] [Indexed: 03/20/2023] Open
Abstract
The increasing incidence of drug resistance in Mycobacterium tuberculosis has diminished the efficacy of almost all available antibiotics, complicating efforts to combat the spread of this global health burden. Alongside the development of new drugs, optimised drug combinations are needed to improve treatment success and prevent the further spread of antibiotic resistance. Typically, antibiotic resistance leads to reduced sensitivity, yet in some cases the evolution of drug resistance can lead to enhanced sensitivity to unrelated drugs. This phenomenon of collateral sensitivity is largely unexplored in M. tuberculosis but has the potential to identify alternative therapeutic strategies to combat drug-resistant strains that are unresponsive to current treatments. Here, by using drug susceptibility profiling, genomics and evolutionary studies we provide evidence for the existence of collateral drug sensitivities in an isogenic collection M. tuberculosis drug-resistant strains. Furthermore, in proof-of-concept studies, we demonstrate how collateral drug phenotypes can be exploited to select against and prevent the emergence of drug-resistant strains. This study highlights that the evolution of drug resistance in M. tuberculosis leads to collateral drug responses that can be exploited to design improved drug regimens.
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Affiliation(s)
- Natalie J E Waller
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Matthew B McNeil
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
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16
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He C, Li B, Gong Z, Huang S, Liu X, Wang J, Xie J, Shi T. Polyphosphate kinase 1 is involved in formation, the morphology and ultramicrostructure of biofilm of Mycobacterium smegmatis and its survivability in macrophage. Heliyon 2023; 9:e14513. [PMID: 36967885 PMCID: PMC10034464 DOI: 10.1016/j.heliyon.2023.e14513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 03/06/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023] Open
Abstract
The most unique characteristic of Mycobacterium tuberculosis is persistence in the human host, and the biofilm formation is related to the persistance. Polyphosphate (polyP) kinase 1 (PPK1) is conserved in Mycobacteria and is responsible for polyP synthesis. polyP is a chain molecule linked by high-energy phosphate bonds, which is considered to play a very important role in bacterial persistence. However, the relationship of PPK1 and mycobacterial biofilm formation is still adequately unclear. In current study, ppk1-deficient mutant (MT), ppk1-complemented (CT) and wild-type strains of M. smegmatis mc2 155 were used to investigate the formation, morphology and ultramicrostructure of the biofilm and to analyze the lipid levels and susceptibility to vancomycin antibiotic. And then WT, MT and CT strains were used to infect macrophages and to analyze the expression levels of various inflammatory factors, respectively. We found that PPK1 was required for M. smegmatis polyP production in vivo and polyP deficiency not only attenuated the biofilm formation, but also altered the phenotype and ultramicrostructure of the biofilm and reduced the cell lipid composition (except for C16.1 and C17.1, most of the fatty acid components from C8-C24). Moreover, the ppk1-deficient mutant was also significantly more sensitive to vancomycin which targets the cell wall, and its ability to survive in macrophages was decreased, which was related to the change of the expression level of inflammatory factors in macrophage. This study demonstrates that the PPK1 can affect the biofilm structure through affecting the content of short chain fatty acid and promote intracellular survival of M. smegmatis by altering the expression of inflammatory factors. These findings establish a basis for investigating the role of PPK1 in the persistence of M. tuberculosis, and provide clues for treating latent infection of M. tuberculosis with PPK1 as a potential drug target.
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Affiliation(s)
- Cailin He
- Medical School of Hubei Minzu University, Enshi, 445000, China
| | - Bo Li
- Medical School of Hubei Minzu University, Enshi, 445000, China
| | - Zhen Gong
- Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Sheng Huang
- Medical School of Hubei Minzu University, Enshi, 445000, China
- Institute of Selenium Science and Industry of Hubei Minzu University, Enshi, 445000, China
| | - Xu Liu
- Medical School of Hubei Minzu University, Enshi, 445000, China
- Institute of Selenium Science and Industry of Hubei Minzu University, Enshi, 445000, China
| | - Jiajun Wang
- Medical School of Hubei Minzu University, Enshi, 445000, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Corresponding author. Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing, 400715, China.
| | - Tingyu Shi
- Medical School of Hubei Minzu University, Enshi, 445000, China
- Hubei Key Laboratory of Biological Resources Protection and Utilization, Enshi, 445000, China
- Institute of Selenium Science and Industry of Hubei Minzu University, Enshi, 445000, China
- Corresponding author. Medical School of Hubei Minzu University, Enshi, 445000, China.
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17
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Dulberger CL, Guerrero-Bustamante CA, Owen SV, Wilson S, Wuo MG, Garlena RA, Serpa LA, Russell DA, Zhu J, Braunecker BJ, Squyres GR, Baym M, Kiessling LL, Garner EC, Rubin EJ, Hatfull GF. Mycobacterial nucleoid-associated protein Lsr2 is required for productive mycobacteriophage infection. Nat Microbiol 2023; 8:695-710. [PMID: 36823286 PMCID: PMC10066036 DOI: 10.1038/s41564-023-01333-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/23/2023] [Indexed: 02/25/2023]
Abstract
Mycobacteriophages are a diverse group of viruses infecting Mycobacterium with substantial therapeutic potential. However, as this potential becomes realized, the molecular details of phage infection and mechanisms of resistance remain ill-defined. Here we use live-cell fluorescence microscopy to visualize the spatiotemporal dynamics of mycobacteriophage infection in single cells and populations, showing that infection is dependent on the host nucleoid-associated Lsr2 protein. Mycobacteriophages preferentially adsorb at Mycobacterium smegmatis sites of new cell wall synthesis and following DNA injection, Lsr2 reorganizes away from host replication foci to establish zones of phage DNA replication (ZOPR). Cells lacking Lsr2 proceed through to cell lysis when infected but fail to generate consecutive phage bursts that trigger epidemic spread of phage particles to neighbouring cells. Many mycobacteriophages code for their own Lsr2-related proteins, and although their roles are unknown, they do not rescue the loss of host Lsr2.
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Affiliation(s)
- Charles L Dulberger
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | | | - Siân V Owen
- Department of Biomedical Informatics and Laboratory of Systems Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Sean Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Michael G Wuo
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Rebecca A Garlena
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lexi A Serpa
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel A Russell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Junhao Zhu
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Ben J Braunecker
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Georgia R Squyres
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Michael Baym
- Department of Biomedical Informatics and Laboratory of Systems Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Laura L Kiessling
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Eric J Rubin
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
| | - Graham F Hatfull
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA.
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18
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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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19
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Naz S, Paritosh K, Sanyal P, Khan S, Singh Y, Varshney U, Nandicoori VK. GWAS and functional studies suggest a role for altered DNA repair in the evolution of drug resistance in Mycobacterium tuberculosis. eLife 2023; 12:75860. [PMID: 36695572 PMCID: PMC9876569 DOI: 10.7554/elife.75860] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/11/2023] [Indexed: 01/26/2023] Open
Abstract
The emergence of drug resistance in Mycobacterium tuberculosis (Mtb) is alarming and demands in-depth knowledge for timely diagnosis. We performed genome-wide association analysis using 2237 clinical strains of Mtb to identify novel genetic factors that evoke drug resistance. In addition to the known direct targets, we identified for the first time, a strong association between mutations in DNA repair genes and the multidrug-resistant phenotype. To evaluate the impact of variants identified in the clinical samples in the evolution of drug resistance, we utilized knockouts and complemented strains in Mycobacterium smegmatis and Mtb. Results show that variant mutations compromised the functions of MutY and UvrB. MutY variant showed enhanced survival compared with wild-type (Rv) when the Mtb strains were subjected to multiple rounds of ex vivo antibiotic stress. In an in vivo guinea pig infection model, the MutY variant outcompeted the wild-type strain. We show that novel variant mutations in the DNA repair genes collectively compromise their functions and contribute to better survival under antibiotic/host stress conditions.
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Affiliation(s)
- Saba Naz
- National Institute of ImmunologyNew DelhiIndia
- Centre for Cellular and Molecular BiologyHyderabadIndia
- Department of Zoology, University of DelhiDelhiIndia
| | - Kumar Paritosh
- Centre for Genetic Manipulation of Crop Plants, University of Delhi South CampusNew DelhiIndia
| | | | - Sidra Khan
- National Institute of ImmunologyNew DelhiIndia
| | | | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science BangaloreBangaloreIndia
| | - Vinay Kumar Nandicoori
- National Institute of ImmunologyNew DelhiIndia
- Centre for Cellular and Molecular BiologyHyderabadIndia
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20
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Singha B, Behera D, Khan MZ, Singh NK, Sowpati DT, Gopal B, Nandicoori VK. The unique N-terminal region of Mycobacterium tuberculosis sigma factor A plays a dominant role in the essential function of this protein. J Biol Chem 2023; 299:102933. [PMID: 36690275 PMCID: PMC10011835 DOI: 10.1016/j.jbc.2023.102933] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 01/11/2023] [Accepted: 01/14/2023] [Indexed: 01/22/2023] Open
Abstract
SigA (σA) is an essential protein and the primary sigma factor in Mycobacterium tuberculosis (Mtb). However, due to the absence of genetic tools, our understanding of the role and regulation of σA activity and its molecular attributes that help modulate Mtb survival is scant. Here, we generated a conditional gene replacement of σA in Mtb and showed that its depletion results in a severe survival defect in vitro, ex vivo, and in vivo in a murine infection model. Our RNA-seq analysis suggests that σA either directly or indirectly regulates ∼57% of the Mtb transcriptome, including ∼28% of essential genes. Surprisingly, we note that despite having ∼64% similarity with σA, overexpression of the primary-like σ factor SigB (σB) fails to compensate for the absence of σA, suggesting minimal functional redundancy. RNA-seq analysis of the Mtb σB deletion mutant revealed that 433 genes are regulated by σB, of which 283 overlap with the σA transcriptome. Additionally, surface plasmon resonance, in vitro transcription, and functional complementation experiments reveal that σA residues between 132-179 that are disordered and missing from all experimentally determined σA-RNAP structural models are imperative for σA function. Moreover, phosphorylation of σA in the intrinsically disordered N-terminal region plays a regulatory role in modulating its activity. Collectively, these observations and analysis provide a rationale for the centrality of σA for the survival and pathogenicity of this bacillus.
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Affiliation(s)
- Biplab Singha
- National Institute of Immunology, New Delhi, India; CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Debashree Behera
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | | | | | | | | | - Vinay Kumar Nandicoori
- National Institute of Immunology, New Delhi, India; CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.
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Eshraghisamani R, Arrazuria R, Luo L, De Buck J. Evaluation of Mycobacterium avium subsp. paratuberculosis isocitrate lyase ( IcL) and ABC transporter ( BacA) knockout mutants as vaccine candidates. Front Cell Infect Microbiol 2023; 13:1149419. [PMID: 37065210 PMCID: PMC10098363 DOI: 10.3389/fcimb.2023.1149419] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 02/28/2023] [Indexed: 04/18/2023] Open
Abstract
There has been little success in controlling Johne's disease, caused by Mycobacterium avium subsp. paratuberculosis, due to suboptimal diagnostics and the ineffectiveness of available vaccines. By knocking out BacA and IcL, genes required for MAP survival in dairy calves, two live-attenuated vaccine candidates were created. This study evaluated the host-specific attenuation of MAP IcL and BacA mutants in mouse and calf models, as well as the elicited immune responses. Deletion mutants were generated in MAP strain A1-157 through specialized transduction and found viable in vitro. First, the mutants' attenuation and elicited cytokine secretion were assessed in a mouse model, 3 weeks after intraperitoneal inoculation with MAP strains. Later, vaccine strains were assessed in a natural host infection model where calves received 109CFU oral dose of MAP wild-type or mutant strains at 2 weeks old. Transcription levels of cytokines in PBMCs were evaluated at 12-, 14-, and 16-weeks post-inoculation (WPI) and MAP colonization in tissue was assessed at 4.5 months after inoculation. Whereas both vaccine candidates colonized mouse tissues similarly to wild-type strain, both failed to persist in calf tissues. In either mouse or calf models, gene deletion did not reduce immunogenicity. Instead, inoculation with ΔBacA induced a greater upregulation of proinflammatory cytokines than ΔIcL and wild-type in both models and a greater expansion of cytotoxic and memory T-cells than uninfected control in calves. ΔBacA and wild-type strains significantly increased secretion of IP-10, MIG, TNFα, and RANTES in mice serum compared to uninfected control. This agreed with upregulation of IL-12, IL-17, and TNFα in calves inoculated with ΔBacA at all time points. The ΔBacA also gave rise to greater populations of CD4+CD45RO+, and CD8+ cells than uninfected control calves at 16 WPI. Low survival rate of MAP in macrophages co-incubated with PBMCs isolated from the ΔBacA group indicated that these cell populations are capable of killing MAP. Overall, the immune response elicited by ΔBacA is stronger compared to ΔIcL and it is maintained over two different models and over time in calves. Further investigation is warranted to evaluate the BacA mutant's protection against MAP infection as a live attenuated vaccine candidate.
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22
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Dong W, Wang G, Bai Y, Li Y, Huo X, Zhao J, Lu W, Lu H, Wang C, Wang X, Chen H, Tan C. Analysis of the noncoding RNA regulatory networks of H37Rv- and H37Rv△1759c-infected macrophages. Front Microbiol 2023; 14:1106643. [PMID: 36992931 PMCID: PMC10042141 DOI: 10.3389/fmicb.2023.1106643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/13/2023] [Indexed: 03/31/2023] Open
Abstract
Noncoding RNAs regulate the process of Mycobacterium tuberculosis (M. tb) infecting the host, but there is no simultaneous transcriptional information of long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) and the global regulatory networks of non-coding RNA. Rv1759c, a virulence factor, is a member of protein family containing the proline-glutamic acid (PE) in M. tb, which can increase M. tb survival. To reveal the noncoding RNA regulatory networks and the effect of Rv1759c on non-coding RNA expression during M. tb infection, we collected samples of H37Rv- and H37Rv△1759c-infected macrophages and explored the full transcriptome expression profile. We found 356 mRNAs, 433 lncRNAs, 168 circRNAs, and 12 miRNAs differentially expressed during H37Rv infection, 356 mRNAs, 433 lncRNAs, 168 circRNAs, and 12 miRNAs differentially expressed during H37Rv△1759c infection. We constructed lncRNA/circRNA-miRNA-mRNA regulatory networks during H37Rv and H37Rv△1759c infection. We demonstrated the role of one of the hubs of the networks, hsa-miR-181b-3p, for H37Rv survival in macrophages. We discovered that the expression changes of 68 mRNAs, 92 lncRNAs, 26 circRNAs, and 3 miRNAs were only related to the deletion of Rv1759c by comparing the transcription profiles of H37Rv and H37Rv△1759c. Here, our study comprehensively characterizes the transcriptional profiles in THP1-derived-macrophages infected with H37Rv and H37Rv△1759c, which provides support and new directions for in-depth exploration of noncoding RNA and PE/PPE family functions during the infection process.
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Affiliation(s)
- Wenqi Dong
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Gaoyan Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yajuan Bai
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yuxin Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xinyu Huo
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Jing Zhao
- WuHan Animal Disease Control Center, Wuhan, Hubei, China
| | - Wenjia Lu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Hao Lu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Chenchen Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiangru Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Chen Tan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
- *Correspondence: Chen Tan,
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23
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Wigger GW, Khani D, Ahmed M, Sayegh L, Auld SC, Fan X, Guidot DM, Staitieh BS. Alcohol impairs recognition and uptake of Mycobacterium tuberculosis by suppressing toll-like receptor 2 expression. Alcohol Clin Exp Res 2022; 46:2214-2224. [PMID: 36281822 PMCID: PMC9772112 DOI: 10.1111/acer.14960] [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: 05/25/2022] [Revised: 09/12/2022] [Accepted: 10/17/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Alcohol impairs pulmonary innate immune function and is associated with an increased risk of tuberculosis (TB). Toll-like receptor 2 (TLR2) is a pattern recognition receptor on alveolar macrophages that recognizes Mycobacterium tuberculosis (Mtb). The expression of TLR2 depends, in part, on granulocyte-macrophage colony-stimulating factor (GM-CSF) signaling. Given our prior work demonstrating the suppression of GM-CSF signaling following chronic alcohol ingestion, we hypothesized that alcohol impairs TLR2 expression via the suppression of GM-CSF and thereby reduces the ability of the macrophage to recognize and phagocytose Mtb. METHODS Primary alveolar macrophages were isolated from control-fed and alcohol-fed rats. Prior to cell isolation, some alcohol-fed rats were treated with intranasal GM-CSF and then endotracheally inoculated with an attenuated strain of Mtb. Primary macrophages were then isolated and immunofluorescence was used to determine phagocytic efficiency and TLR2 expression in the presence and absence of GM-CSF treatment and phagocytic efficiency in the presence and absence of TLR2 neutralization. RESULTS TLR2 expression and phagocytosis of Mtb were significantly lower in the alveolar macrophages of alcohol-fed rats than control-fed rats. In parallel, blocking TLR2 signaling recapitulated this decreased phagocytosis of Mtb. In contrast, intranasal GM-CSF treatment restored TLR2 expression and Mtb phagocytosis in the alveolar macrophages of alcohol-fed rats to levels comparable to those of control-fed rats. CONCLUSIONS Chronic alcohol ingestion reduces TLR2 protein expression and phagocytosis of Mtb, likely due to impaired GM-CSF signaling. GM-CSF restores membrane-bound TLR2 expression and phagocytic function.
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Affiliation(s)
- Gregory W Wigger
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Darya Khani
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Mariam Ahmed
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Layal Sayegh
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Sara C Auld
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | - Xian Fan
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David M Guidot
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Bashar S Staitieh
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
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24
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Armianinova DK, Karpov DS, Kotliarova MS, Goncharenko AV. Genetic Engineering in Mycobacteria. Mol Biol 2022. [DOI: 10.1134/s0026893322060036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Abstract
Genetic tools for targeted modification of the mycobacterial genome contribute to the understanding of the physiology and virulence mechanisms of mycobacteria. Human and animal pathogens, such as the Mycobacterium tuberculosis complex, which causes tuberculosis, and M. leprae, which causes leprosy, are of particular importance. Genetic research opens up novel opportunities to identify and validate new targets for antibacterial drugs and to develop improved vaccines. Although mycobacteria are difficult to work with due to their slow growth rate and a limited possibility to transfer genetic information, significant progress has been made in developing genetic engineering methods for mycobacteria. The review considers the main approaches to changing the mycobacterial genome in a targeted manner, including homologous and site-specific recombination and use of the CRISPR/Cas system.
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25
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Donegan RK, Fu Y, Copeland J, Idga S, Brown G, Hale OF, Mitra A, Yang H, Dailey HA, Niederweis M, Jain P, Reddi AR. Exogenously Scavenged and Endogenously Synthesized Heme Are Differentially Utilized by Mycobacterium tuberculosis. Microbiol Spectr 2022; 10:e0360422. [PMID: 36169423 PMCID: PMC9604157 DOI: 10.1128/spectrum.03604-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 09/13/2022] [Indexed: 01/12/2023] Open
Abstract
Heme is both an essential cofactor and an abundant source of nutritional iron for the human pathogen Mycobacterium tuberculosis. While heme is required for M. tuberculosis survival and virulence, it is also potentially cytotoxic. Since M. tuberculosis can both synthesize and take up heme, the de novo synthesis of heme and its acquisition from the host may need to be coordinated in order to mitigate heme toxicity. However, the mechanisms employed by M. tuberculosis to regulate heme uptake, synthesis, and bioavailability are poorly understood. By integrating ratiometric heme sensors with mycobacterial genetics, cell biology, and biochemistry, we determined that de novo-synthesized heme is more bioavailable than exogenously scavenged heme, and heme availability signals the downregulation of heme biosynthetic enzyme gene expression. Ablation of heme synthesis does not result in the upregulation of known heme import proteins. Moreover, we found that de novo heme synthesis is critical for survival from macrophage assault. Altogether, our data suggest that mycobacteria utilize heme from endogenous and exogenous sources differently and that targeting heme synthesis may be an effective therapeutic strategy to treat mycobacterial infections. IMPORTANCE Mycobacterium tuberculosis infects ~25% of the world's population and causes tuberculosis (TB), the second leading cause of death from infectious disease. Heme is an essential metabolite for M. tuberculosis, and targeting the unique heme biosynthetic pathway of M. tuberculosis could serve as an effective therapeutic strategy. However, since M. tuberculosis can both synthesize and scavenge heme, it was unclear if inhibiting heme synthesis alone could serve as a viable approach to suppress M. tuberculosis growth and virulence. The importance of this work lies in the development and application of genetically encoded fluorescent heme sensors to probe bioavailable heme in M. tuberculosis and the discovery that endogenously synthesized heme is more bioavailable than exogenously scavenged heme. Moreover, it was found that heme synthesis protected M. tuberculosis from macrophage killing, and bioavailable heme in M. tuberculosis is diminished during macrophage infection. Altogether, these findings suggest that targeting M. tuberculosis heme synthesis is an effective approach to combat M. tuberculosis infections.
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Affiliation(s)
- Rebecca K. Donegan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
- Department of Chemistry, Barnard College, New York, New York, USA
| | - Yibo Fu
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Jacqueline Copeland
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Stanzin Idga
- Department of Pathology, Laura and Isaac Perlmutter Cancer Center, New York University Grossman School of Medicine, New York, New York, USA
| | - Gabriel Brown
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Owen F. Hale
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Avishek Mitra
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hui Yang
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Harry A. Dailey
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Paras Jain
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
- Cell Therapy and Cell Engineering Laboratory, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Amit R. Reddi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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26
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Liang YC, Berton S, Reeks C, Sun J. An in vivo biosafety-level-2-compatible model of Mycobacterium tuberculosis infection for drug susceptibility testing. STAR Protoc 2022; 3:101575. [PMID: 35880128 PMCID: PMC9307682 DOI: 10.1016/j.xpro.2022.101575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Available mouse models for tuberculosis drug susceptibility testing requires using virulent biosafety-level-3 (BSL-3) Mycobacterium tuberculosis (Mtb) strains, or attenuated BSL-2 strains that lack virulence genes. Here, we present a BSL-2-compatible mouse model for tuberculosis drug susceptibility testing using the auxotrophic Mtb mc26206 strain, which retains all virulence genes. Using rifampicin and a new autophagy-boosting compound, SMIP-30, we provide a step-by-step guide for the infection, drug administration, and evaluation of Mtb burden and cytokine profiles. This protocol is easily adaptable for testing of other antibiotics and host-directed compounds. For complete details on the use and execution of this protocol, please refer to Berton et al. (2022). BSL-2 murine model of drug susceptibility testing against Mycobacterium tuberculosis Auxotrophic strain of Mycobacterium tuberculosis retaining all virulence genes Parallel measurement of bacterial burden and cytokine profiling in infected mice Easily adaptable to test combinations of antibiotics and host-directed compounds
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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27
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Wu J, Luo FL, Xie Y, Xiong H, Gao Y, Liu G, Zhang XL. EST12 regulates Myc expression and enhances anti-mycobacterial inflammatory response via RACK1-JNK-AP1-Myc immune pathway. Front Immunol 2022; 13:943174. [PMID: 36003390 PMCID: PMC9393728 DOI: 10.3389/fimmu.2022.943174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
c-Myc (Myc) is a well-known transcription factor that regulates many essential cellular processes. Myc has been implicated in regulating anti-mycobacterial responses. However, its precise mechanism in modulating mycobacterial immunity remains elusive. Here, we found that a secreted Rv1579c (early secreted target with molecular weight 12 kDa, named EST12) protein, encoded by virulent Mycobacterium tuberculosis (M.tb) H37Rv region of deletion (RD)3, induces early expression and late degradation of Myc protein. Interestingly, EST12-induced Myc was further processed by K48 ubiquitin proteasome degradation in E3 ubiquitin ligase FBW7 dependent manner. EST12 protein activates JNK-AP1-Myc signaling pathway, promotes Myc binding to the promoters of IL-6, TNF-α and iNOS, then induces the expression of pro-inflammatory cytokines (IL-6 and TNF-α)/inducible nitric oxide synthase (iNOS)/nitric oxide (NO) to increase mycobacterial clearance in a RACK1 dependent manner, and these effects are impaired by both Myc and JNK inhibitors. Macrophages infected with EST12-deficiency strain (H37RvΔEST12) displayed less production of iNOS, IL-6 and TNF-α. In conclusion, EST12 regulates Myc expression and enhances anti-mycobacterial inflammatory response via RACK1-JNK-AP1-Myc immune pathway. Our finding provides new insights into M.tb-induced immunity through Myc.
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Affiliation(s)
- Jian Wu
- Hubei Province Key Laboratory of Allergy and Immunology and Department of Immunology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Feng-Ling Luo
- Hubei Province Key Laboratory of Allergy and Immunology and Department of Immunology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Yan Xie
- Hubei Province Key Laboratory of Allergy and Immunology and Department of Immunology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Huan Xiong
- Hubei Province Key Laboratory of Allergy and Immunology and Department of Immunology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Yadong Gao
- Department of Allergy, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Guanghui Liu
- Department of Allergy, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xiao-Lian Zhang
- Hubei Province Key Laboratory of Allergy and Immunology and Department of Immunology, Wuhan University School of Basic Medical Sciences, Wuhan, China
- Department of Allergy, Zhongnan Hospital of Wuhan University, Wuhan, China
- State Key Laboratory of Virology, Frontier Science Center for Immunology and Metabolism and Medical Research Institute, Wuhan University, Wuhan, China
- Wuhan Research Center for Infectious Diseases and Cancer, Chinese Academy of Medical Sciences, Wuhan, China
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28
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Zang X, Dang G, Cai Z, Shao M, Tang Y, Cao J, Cui Z, Liu S. Extracellular DNase MAP3916c attacks the neutrophil extracellular traps and is needed for Mycobacterium avium subsp. paratuberculosis virulence. Vet Microbiol 2022; 273:109529. [PMID: 35944391 DOI: 10.1016/j.vetmic.2022.109529] [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: 01/05/2022] [Revised: 07/29/2022] [Accepted: 08/02/2022] [Indexed: 11/27/2022]
Abstract
Extracellular DNases/nucleases are important virulence factors in many bacteria. However, no DNase/nucleases have been reported in Mycobacterium avium subsp. paratuberculosis (MAP), which is a pathogen of paratuberculosis. Genome analyses of MAP K-10 revealed that the map3916c gene putatively encodes a nuclease. In this study, we show that MAP3916c is an extracellular nonspecific DNase requiring a divalent cation, especially Mg2+. The optimum DNase activity of MAP3916c was exhibited at 41 °C and pH 9.0. Site-directed mutagenesis studies indicated that 125-Histidine is necessary for MAP3916c DNase activity. In addition, MAP3916c DNase could destroy the neutrophil extracellular traps (NETs) induced by Phorbol 12-myristate 13-acetate in vitro and degrade the NETs induced by MAP K-10 upon infection. Furthermore, MAP3916c DNase promoted the colonization of MAP K-10, induced the formation of granulomas in the liver and small intestine and promoted the release of IL-1β, IL-6 and TNF-α inflammatory cytokines during the infection of mice. These results indicated that MAP3916c is relevant to NETs escape and the pathogenicity of MAP. It also provides a basis for further study of the function of nuclease activity on the MAP immune evasion.
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Affiliation(s)
- Xinxin Zang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Guanghui Dang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Zhuming Cai
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Mingzhu Shao
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Yangyang Tang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China; College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Jun Cao
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Ziyin Cui
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China.
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29
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Krause AL, Stinear TP, Monk IR. Barriers to genetic manipulation of Enterococci: Current Approaches and Future Directions. FEMS Microbiol Rev 2022; 46:6650352. [PMID: 35883217 PMCID: PMC9779914 DOI: 10.1093/femsre/fuac036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 07/14/2022] [Accepted: 07/22/2022] [Indexed: 01/09/2023] Open
Abstract
Enterococcus faecalis and Enterococcus faecium are Gram-positive commensal gut bacteria that can also cause fatal infections. To study clinically relevant multi-drug resistant E. faecalis and E. faecium strains, methods are needed to overcome physical (thick cell wall) and enzymatic barriers that limit the transfer of foreign DNA and thus prevent facile genetic manipulation. Enzymatic barriers to DNA uptake identified in E. faecalis and E. faecium include type I, II and IV restriction modification systems and CRISPR-Cas. This review examines E. faecalis and E. faecium DNA defence systems and the methods with potential to overcome these barriers. DNA defence system bypass will allow the application of innovative genetic techniques to expedite molecular-level understanding of these important, but somewhat neglected, pathogens.
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Affiliation(s)
- Alexandra L Krause
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, VIC 3000 Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, VIC 3000 Australia
| | - Ian R Monk
- Corresponding author: Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, VIC 3000 Australia. E-mail:
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30
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Abstract
Mycobacteriophages-bacteriophages infecting Mycobacterium hosts-contribute substantially to our understanding of viral diversity and evolution, provide resources for advancing Mycobacterium genetics, are the basis of high-impact science education programs, and show considerable therapeutic potential. Over 10,000 individual mycobacteriophages have been isolated by high school and undergraduate students using the model organism Mycobacterium smegmatis mc2155 and 2,100 have been completely sequenced, giving a high-resolution view of the phages that infect a single common host strain. The phage genomes are revealed to be highly diverse and architecturally mosaic and are replete with genes of unknown function. Mycobacteriophages have provided many widely used tools for Mycobacterium genetics including integration-proficient vectors and recombineering systems, as well as systems for efficient delivery of reporter genes, transposons, and allelic exchange substrates. The genomic insights and engineering tools have facilitated exploration of phages for treatment of Mycobacterium infections, although their full therapeutic potential has yet to be realized.
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31
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Role of a Putative Alkylhydroperoxidase Rv2159c in the Oxidative Stress Response and Virulence of Mycobacterium tuberculosis. Pathogens 2022; 11:pathogens11060684. [PMID: 35745538 PMCID: PMC9227533 DOI: 10.3390/pathogens11060684] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 05/26/2022] [Accepted: 05/31/2022] [Indexed: 02/04/2023] Open
Abstract
Mycobacterium tuberculosis, which causes tuberculosis, is one of the leading infectious agents worldwide with a high rate of mortality. Following aerosol inhalation, M. tuberculosis primarily infects the alveolar macrophages, which results in a host immune response that gradually activates various antimicrobial mechanisms, including the production of reactive oxygen species (ROS), within the phagocytes to neutralize the bacteria. OxyR is the master regulator of oxidative stress response in several bacterial species. However, due to the absence of a functional oxyR locus in M. tuberculosis, the peroxidase stress is controlled by alkylhydroperoxidases. M. tuberculosis expresses alkylhydroperoxide reductase to counteract the toxic effects of ROS. In the current study, we report the functional characterization of an orthologue of alkylhydroperoxidase family member, Rv2159c, a conserved protein with putative peroxidase activity, during stress response and virulence of M. tuberculosis. We generated a gene knockout mutant of M. tuberculosis Rv2159c (MtbΔ2159) by specialized transduction. The MtbΔ2159 was sensitive to oxidative stress and exposure to toxic transition metals. In a human monocyte (THP-1) cell infection model, MtbΔ2159 showed reduced uptake and intracellular survival and increased expression of pro-inflammatory molecules, including IL-1β, IP-10, and MIP-1α, compared to the wild type M. tuberculosis and Rv2159c-complemented MtbΔ2159 strains. Similarly, in a guinea pig model of pulmonary infection, MtbΔ2159 displayed growth attenuation in the lungs, compared to the wild type M. tuberculosis and Rv2159c-complemented MtbΔ2159 strains. Our study suggests that Rv2159c has a significant role in maintaining the cellular homeostasis during stress and virulence of M. tuberculosis.
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Single-Fluorescence ATP Sensor Based on Fluorescence Resonance Energy Transfer Reveals Role of Antibiotic-Induced ATP Perturbation in Mycobacterial Killing. mSystems 2022; 7:e0020922. [PMID: 35615956 PMCID: PMC9238375 DOI: 10.1128/msystems.00209-22] [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] [Indexed: 11/24/2022] Open
Abstract
The rapid emergence of multidrug-resistant/extensively drug-resistant tuberculosis (TB) is responsible for treatment failure in patients with TB and significantly endangers global public health. Recently, bioenergetics has become a new paradigm for anti-TB drug discovery and is based on the link between bacterial ATP levels and drug efficacy. A better understanding of the role of ATP fluctuations during antibiotic treatment may provide insight into antibiotic-mediated killing of mycobacteria. Here, we employed an advanced single-fluorescence FRET (fluorescence resonance energy transfer)-based ATP biosensor, ATPser, for the stable and convenient detection of intracellular ATP fluctuations in mycobacteria. This strategy correlated closely with the results obtained from conventional luminescence ATP assays, indicating the reliability of the system for bioenergetics analysis in mycobacteria. Moreover, the reporter strains expressing ATPser displayed obvious ATP changes when subjected to different stresses, such as starvation and ATP depletion. Interestingly, we observed that different antibiotics induced fluctuations in cellular ATP levels in individual cells of various magnitudes, revealing a strong connection between ATP fluctuations and drug efficacy. Furthermore, drug combinations accelerated ATP perturbation, resulting in increased cell death. We concluded that ATPser enabled real-time measurement of ATP at the single-cell level in mycobacteria, and monitoring ATP dynamics in drug-treated bacteria may shed light on novel treatment strategies. IMPORTANCE Bioenergetics has emerged as a new paradigm for antituberculosis (anti-TB) drug discovery, and the cellular ATP level is the core indicator reflecting bacterial metabolic homeostasis. Although several bulk assays have been designed for the measurement of cellular ATP content, a more convenient strategy is required for real-time ATP measurement of single viable cells. In this study, by combining the ε-subunit of Bacillus subtilis FoF1-ATP synthase with a circularly permuted green fluorescent protein [(cp)GFP], we constructed a FRET-based single-fluorescence ATP sensor, ATPser, for real-time single-cell ATP detection among a mycobacterial population. Using the ATPser, we designed different drug combinations containing components that have similar/opposite effects on ATP alternation. Our results demonstrated that increased cellular ATP fluctuations were associated with depletion of mycobacterial viability, while counteracting ATP fluctuations weakened the killing effect of the drug regime. Thus, potentially efficient drug combinations can be considered based on their similar effects on mycobacterial ATP levels, and ATPser may be a useful tool to study mycobacterial bioenergetics and to guide drug regime design.
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Dong W, Wang G, Feng J, Li P, Wang R, Lu H, Lu W, Wang C, Wang X, Chen H, Xiang Y, Tan C. MiR-25 blunts autophagy and promotes the survival of Mycobacterium tuberculosis by regulating NPC1. iScience 2022; 25:104279. [PMID: 35586071 PMCID: PMC9108763 DOI: 10.1016/j.isci.2022.104279] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 03/28/2022] [Accepted: 04/19/2022] [Indexed: 02/08/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) evades host clearance by inhibiting autophagy. MicroRNA-25 (miR-25) expression was significantly up-regulated in the lung tissues of mice infected with Bacillus Calmette-Guerin (BCG) and macrophages infected with Mtb or BCG, especially in the early stages of infection. MiR-25 can significantly increase the survival of Mtb and BCG in macrophages. We validated that miR-25 targets the NPC1 protein located on the lysosomal membrane, resulting in damage to lysosomal function, thereby inhibiting autophagolysosome formation and promoting the survival of Mtb and BCG. Consistently, mice lacking miR-25 exhibited more resistant to BCG infection. In addition, we found that Rv1759c induces the expression of miR-25 through NFKB inhibitor zeta (NFKBIZ). This study demonstrates that the role of miR-25 during Mtb infection contributes to a better understanding of the pathogenesis of tuberculosis (TB). Mtb up-modulates miR-25 expression especially in the early stage of infection miR-25 targeting NPC1 impairs autophagic flux in macrophages Mice lacking miR-25 exhibits more resistant to BCG infection Rv1759c regulates miR-25 expression and Mtb survival via NFKBIZ
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Affiliation(s)
- Wenqi Dong
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Gaoyan Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Jiajia Feng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Pei Li
- Department of Gastrointestinal Surgery, The Second Clinical Medical College of Jinan University, Shenzhen, Guangdong, China
| | - Rui Wang
- Department of Experimental Animal Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Hao Lu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Wenjia Lu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Chenchen Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Xiangru Wang
- Hubei Hongshan Laboratory, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei, China.,Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People's Republic of China, Wuhan, Hubei, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Hongshan Laboratory, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei, China.,Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People's Republic of China, Wuhan, Hubei, China
| | - Yaozu Xiang
- School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chen Tan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Hubei Hongshan Laboratory, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei, China.,Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People's Republic of China, Wuhan, Hubei, China
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Mycobacterium tuberculosis Transcription Factor EmbR Regulates the Expression of Key Virulence Factors That Aid in Ex Vivo and In Vivo Survival. mBio 2022; 13:e0383621. [PMID: 35471080 PMCID: PMC9239209 DOI: 10.1128/mbio.03836-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium tuberculosis encodes ~200 transcription factors that modulate gene expression under different microenvironments in the host. Even though high-throughput chromatin immunoprecipitation sequencing and transcriptome sequencing (RNA-seq) studies have identified the regulatory network for ~80% of transcription factors, many transcription factors remain uncharacterized. EmbR is one such transcription factor whose in vivo regulon and biological function are yet to be elucidated. Previous in vitro studies suggested that phosphorylation of EmbR by PknH upregulates the embCAB operon. Using a gene replacement mutant of embR, we investigated its role in modulating cellular morphology, antibiotic resistance, and survival in the host. Contrary to the prevailing hypothesis, under normal growth conditions, EmbR is neither phosphorylated nor impacted by ethambutol resistance through the regulation of the embCAB operon. The embR deletion mutant displayed attenuated M. tuberculosis survival in vivo. RNA-seq analysis suggested that EmbR regulates operons involved in the secretion pathway, lipid metabolism, virulence, and hypoxia, including well-known hypoxia-inducible genes devS and hspX. Lipidome analysis revealed that EmbR modulates levels of all lysophospholipids, several phospholipids, and M. tuberculosis-specific lipids, which is more pronounced under hypoxic conditions. We found that the EmbR mutant is hypersusceptible to hypoxic stress, and RNA sequencing performed under hypoxic conditions indicated that EmbR majorly regulates genes involved in response to acidic pH, hypoxia, and fatty acid metabolism. We observed condition-specific phosphorylation of EmbR, which contributes to EmbR-mediated transcription of several essential genes, ensuring enhanced survival. Collectively, the study establishes EmbR as a key modulator of hypoxic response that facilitates mycobacterial survival in the host.
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35
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Harold LK, Jinich A, Hards K, Cordeiro A, Keighley LM, Cross A, McNeil MB, Rhee K, Cook GM. Deciphering functional redundancy and energetics of malate oxidation in mycobacteria. J Biol Chem 2022; 298:101859. [PMID: 35337802 PMCID: PMC9062433 DOI: 10.1016/j.jbc.2022.101859] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 03/20/2022] [Accepted: 03/21/2022] [Indexed: 02/07/2023] Open
Abstract
Oxidation of malate to oxaloacetate, catalyzed by either malate dehydrogenase (Mdh) or malate quinone oxidoreductase (Mqo), is a critical step of the tricarboxylic acid cycle. Both Mqo and Mdh are found in most bacterial genomes, but the level of functional redundancy between these enzymes remains unclear. A bioinformatic survey revealed that Mqo was not as widespread as Mdh in bacteria but that it was highly conserved in mycobacteria. We therefore used mycobacteria as a model genera to study the functional role(s) of Mqo and its redundancy with Mdh. We deleted mqo from the environmental saprophyte Mycobacterium smegmatis, which lacks Mdh, and found that Mqo was essential for growth on nonfermentable carbon sources. On fermentable carbon sources, the Δmqo mutant exhibited delayed growth and lowered oxygen consumption and secreted malate and fumarate as terminal end products. Furthermore, heterologous expression of Mdh from the pathogenic species Mycobacterium tuberculosis shortened the delayed growth on fermentable carbon sources and restored growth on nonfermentable carbon sources at a reduced growth rate. In M. tuberculosis, CRISPR interference of either mdh or mqo expression resulted in a slower growth rate compared to controls, which was further inhibited when both genes were knocked down simultaneously. These data reveal that exergonic Mqo activity powers mycobacterial growth under nonenergy limiting conditions and that endergonic Mdh activity complements Mqo activity, but at an energetic cost for mycobacterial growth. We propose Mdh is maintained in slow-growing mycobacterial pathogens for use under conditions such as hypoxia that require reductive tricarboxylic acid cycle activity.
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Affiliation(s)
- Liam K Harold
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand.
| | - Adrian Jinich
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Kiel Hards
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Alexandra Cordeiro
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Laura M Keighley
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Alec Cross
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Matthew B McNeil
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Kyu Rhee
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Gregory M Cook
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand.
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36
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A selective PPM1A inhibitor activates autophagy to restrict the survival of Mycobacterium tuberculosis. Cell Chem Biol 2022; 29:1126-1139.e12. [PMID: 35320734 DOI: 10.1016/j.chembiol.2022.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 02/01/2022] [Accepted: 03/03/2022] [Indexed: 12/19/2022]
Abstract
Metal-dependent protein phosphatases (PPMs) have essential roles in a variety of cellular processes, including inflammation, proliferation, differentiation, and stress responses, which are intensively investigated in cancer and metabolic diseases. Targeting PPMs to modulate host immunity in response to pathogens is an ambitious proposition. The feasibility of such a strategy is unproven because development of inhibitors against PPMs is challenging and suffers from poor selectivity. Combining a biomimetic modularization strategy with function-oriented synthesis, we design, synthesize and screen more than 500 pseudo-natural products, resulting in the discovery of a potent, selective, and non-cytotoxic small molecule inhibitor for PPM1A, SMIP-30. Inhibition of PPM1A with SMIP-30 or its genetic ablation (ΔPPM1A) activated autophagy through a mechanism dependent on phosphorylation of p62-SQSTM1, which restricted the intracellular survival of Mycobacterium tuberculosis in macrophages and in the lungs of infected mice. SMIP-30 provides proof of concept that PPMs are druggable and promising targets for the development of host-directed therapies against tuberculosis.
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37
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Multiple genetic paths including massive gene amplification allow Mycobacterium tuberculosis to overcome loss of ESX-3 secretion system substrates. Proc Natl Acad Sci U S A 2022; 119:2112608119. [PMID: 35193958 PMCID: PMC8872769 DOI: 10.1073/pnas.2112608119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2021] [Indexed: 01/18/2023] Open
Abstract
The Mycobacterium tuberculosis (Mtb) ESX-3 type VII secretion system plays a critical role in iron acquisition. Infection of mice with highly attenuated Mtb deletion mutants lacking esxG or esxH, genes encoding key ESX-3 substrates, unexpectedly yielded suppressor mutants with restored capacity to grow in vivo and in vitro in the absence of iron supplementation. Whole-genome sequencing identified two mechanisms of suppression, the disruption of a transcriptional repressor that regulates expression of an ESX-3 paralogous region encoding EsxR and EsxS, and a massive 38- to 60-fold gene amplification of this same region. These data are significant because they reveal a previously unrecognized iron acquisition regulon and inform mechanisms of Mtb chromosome evolution. Mycobacterium tuberculosis (Mtb) possesses five type VII secretion systems (T7SS), virulence determinants that include the secretion apparatus and associated secretion substrates. Mtb strains deleted for the genes encoding substrates of the ESX-3 T7SS, esxG or esxH, require iron supplementation for in vitro growth and are highly attenuated in vivo. In a subset of infected mice, suppressor mutants of esxG or esxH deletions were isolated, which enabled growth to high titers or restored virulence. Suppression was conferred by mechanisms that cause overexpression of an ESX-3 paralogous region that lacks genes for the secretion apparatus but encodes EsxR and EsxS, apparent ESX-3 orphan substrates that functionally compensate for the lack of EsxG or EsxH. The mechanisms include the disruption of a transcriptional repressor and a massive 38- to 60-fold gene amplification. These data identify an iron acquisition regulon, provide insight into T7SS, and reveal a mechanism of Mtb chromosome evolution involving “accordion-type” amplification.
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38
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Babu Sait MR, Koliwer-Brandl H, Stewart JA, Swarts BM, Jacobsen M, Ioerger TR, Kalscheuer R. PPE51 mediates uptake of trehalose across the mycomembrane of Mycobacterium tuberculosis. Sci Rep 2022; 12:2097. [PMID: 35136132 PMCID: PMC8826857 DOI: 10.1038/s41598-022-06109-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/19/2022] [Indexed: 01/07/2023] Open
Abstract
The disaccharide trehalose is essential for viability of Mycobacterium tuberculosis, which synthesizes trehalose de novo but can also utilize exogenous trehalose. The mycobacterial cell wall encompasses two permeability barriers, the cytoplasmic membrane and the outer mycolic acid-containing mycomembrane. The ABC transporter LpqY-SugA-SugB-SugC has previously been demonstrated to mediate the specific uptake of trehalose across the cytoplasmic membrane. However, it is still unclear how the transport of trehalose molecules across the mycomembrane is mediated. In this study, we harnessed the antimycobacterial activity of the analogue 6-azido trehalose to select for spontaneous resistant M. tuberculosis mutants in a merodiploid strain harbouring two LpqY-SugA-SugB-SugC copies. Mutations mediating resistance to 6-azido trehalose mapped to the proline-proline-glutamate (PPE) family member PPE51 (Rv3136), which has recently been shown to be an integral mycomembrane protein involved in uptake of low-molecular weight compounds. A site-specific ppe51 gene deletion mutant of M. tuberculosis was unable to grow on trehalose as the sole carbon source. Furthermore, bioorthogonal labelling of the M. tuberculosis Δppe51 mutant incubated with 6-azido trehalose corroborated the impaired internalization. Taken together, the results indicate that the transport of trehalose and trehalose analogues across the mycomembrane of M. tuberculosis is exclusively mediated by PPE51.
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Affiliation(s)
- Mohammed Rizwan Babu Sait
- Institute of Pharmaceutical Biology and Biotechnology, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Hendrik Koliwer-Brandl
- Institute of Pharmaceutical Biology and Biotechnology, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Jessica A Stewart
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI, 48859, USA
| | - Benjamin M Swarts
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI, 48859, USA
| | - Marc Jacobsen
- Department of General Pediatrics, Neonatology, and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Thomas R Ioerger
- Department of Computer Science, Texas A&M University, College Station, TX, 77843, USA
| | - Rainer Kalscheuer
- Institute of Pharmaceutical Biology and Biotechnology, Heinrich Heine University, 40225, Düsseldorf, Germany.
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Yang F, Xu L, Liang L, Liang W, Li J, Lin D, Dai M, Zhou D, Li Y, Chen Y, Zhao H, Tian GB, Feng S. The Involvement of Mycobacterium Type III-A CRISPR-Cas System in Oxidative Stress. Front Microbiol 2021; 12:774492. [PMID: 34956138 PMCID: PMC8696179 DOI: 10.3389/fmicb.2021.774492] [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: 09/12/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
Type I and type II CRISPR-Cas systems are employed to evade host immunity by targeting interference of bacteria’s own genes. Although Mycobacterium tuberculosis (M. tuberculosis), the causative agent of tuberculosis, possesses integrated type III-A CRISPR-Cas system, its role in mycobacteria remains obscure. Here, we observed that seven cas genes (csm2∼5, cas10, cas6) were upregulated in Mycobacterium bovis BCG under oxidative stress treatment, indicating the role of type III-A CRISPR-Cas system in oxidative stress. To explore the functional role of type III-A CRISPR-Cas system, TCC (Type III-A CRISPR-Cas system, including cas6, cas10, and csm2-6) mutant was generated. Deletion of TCC results in increased sensitivity in response to hydrogen peroxide and reduced cell envelope integrity. Analysis of RNA-seq dataset revealed that TCC impacted on the oxidation-reduction process and the composition of cell wall which is essential for mycobacterial envelop integrity. Moreover, disrupting TCC led to poor intracellular survival in vivo and in vitro. Finally, we showed for the first time that TCC contributed to the regulation of regulatory T cell population, supporting a role of TCC in modulating host immunity. Our finding reveals the important role of TCC in cell envelop homeostasis. Our work also highlights type III-A CRISPR-Cas system as an important factor for intracellular survival and host immunoregulation in mycobacteria, thus may be a potential target for therapy.
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Affiliation(s)
- Fan Yang
- Department of Microbiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Lingqing Xu
- Department of Clinical Laboratory, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Lujie Liang
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Wanfei Liang
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Jiachen Li
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Daixi Lin
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Min Dai
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, China
| | - Dianrong Zhou
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yaxin Li
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yong Chen
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, China
| | - Hui Zhao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Guo-Bao Tian
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Siyuan Feng
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
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40
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Cheung CY, McNeil MB, Cook GM. Utilization of CRISPR interference to investigate the contribution of genes to pathogenesis in a macrophage model of Mycobacterium tuberculosis infection. J Antimicrob Chemother 2021; 77:615-619. [PMID: 34850009 DOI: 10.1093/jac/dkab437] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 10/29/2021] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVES There is an urgent need for novel drugs that target unique cellular pathways to combat infections caused by Mycobacterium tuberculosis. CRISPR interference (CRISPRi)-mediated transcriptional repression has recently been developed for use in mycobacteria as a genetic tool for identifying and validating essential genes as novel drug targets. Whilst CRISPRi has been applied to extracellular bacteria, no studies to date have determined whether CRISPRi can be used in M. tuberculosis infection models. METHODS Using the human monocytic macrophage-like THP-1 cell line as a model for M. tuberculosis infection we investigated if CRISPRi can be activated within intracellular M. tuberculosis. RESULTS The transcriptional repression of two candidate M. tuberculosis genes, i.e. mmpL3 and qcrB, leads to a reduction in viable M. tuberculosis within infected THP-1 cells. The reduction in viable colonies is dependent on both the level of CRISPRi-mediated repression and the duration of repression. CONCLUSIONS These results highlight the utility of CRISPRi in exploring mycobacterial gene function and essentiality under a variety of conditions pertinent to host infection.
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Affiliation(s)
- Chen-Yi Cheung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Matthew B McNeil
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
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Murphy KC. Oligo-Mediated Recombineering and its Use for Making SNPs, Knockouts, Insertions, and Fusions in Mycobacterium tuberculosis. Methods Mol Biol 2021; 2314:301-321. [PMID: 34235660 DOI: 10.1007/978-1-0716-1460-0_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Phage recombination systems have been instrumental in the development of gene modification technologies for bacterial pathogens. In particular, the Che9 phage RecET system has been used successfully for over 10 years for making gene knockouts and fusions in Mycobacterium tuberculosis. This "recombineering" technology typically uses linear dsDNA substrates that contain a drug-resistance marker flanked by (up to) 500 base pairs of DNA homologous to the target site. Less often employed in mycobacterial recombineering is the use of oligonucleotides, which require only the action of the RecT annealase to align oligos to ssDNA regions of the replication fork, for subsequent incorporation into the chromosome. Despite the higher frequency of such events relative to dsDNA-promoted recombineering, oligo-mediated changes generally suffer from the disadvantage of not being selectable, thus making them harder to isolate. This chapter discusses steps and methodologies that increase the frequencies of finding oligo-mediated events, including the transfer of single nucleotide polymorphisms (SNPs) to mycobacterial chromosomes, and the use of oligos in conjunction with the mycobacterial phage Bxb1 site-specific recombination system for the easy generation of knockouts, insertion, and fusions, in a protocol known as ORBIT.
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Affiliation(s)
- Kenan C Murphy
- Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA.
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42
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MAB_2355c Confers Macrolide Resistance in Mycobacterium abscessus by Ribosome Protection. Antimicrob Agents Chemother 2021; 65:e0033021. [PMID: 34097497 PMCID: PMC8373217 DOI: 10.1128/aac.00330-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Macrolide resistance is always a concern when treating Mycobacterium abscessus infections. MAB_2355c was identified previously as a possible new factor that confers the intrinsic resistance of 194 clinical M. abscessus isolates to clarithromycin. Herein, the potential mechanism by which MAB_2355c exerts macrolide resistance was explored by bioinformatics analysis, MAB_2355c cloning and protein purification, ATP hydrolysis assay, gene knockout and complementation, antibiotic sensitivity, and transcription-translation assays. MAB_2355c is a putative ATP-binding cassette F (ABC-F) family protein. Purified MAB_2355c protein exhibits ATP hydrolysis activity, which can be inhibited by ribosome-targeting antibiotics. MAB_2355c mRNA expression is upregulated more significantly after exposure to macrolides than after exposure to other ribosome-targeting antibiotics. MAB_2355c deleted strains showed increased sensitivity to macrolides, which was reduced by MAB_2355c complementation. Finally, MAB_2355c rescued the transcription and translation activities affected by macrolides in vitro. These findings suggest that MAB_2355c confers the resistance of M. abscessus to macrolides by ribosome protection, thus complementing other known resistance mechanisms.
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Khan MZ, Singha B, Ali MF, Taunk K, Rapole S, Gourinath S, Nandicoori VK. Redox homeostasis in Mycobacterium tuberculosis is modulated by a novel actinomycete-specific transcription factor. EMBO J 2021; 40:e106111. [PMID: 34018220 PMCID: PMC8280819 DOI: 10.15252/embj.2020106111] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 04/17/2021] [Accepted: 04/20/2021] [Indexed: 11/09/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) has evolved diverse cellular processes in response to the multiple stresses it encounters within the infected host. We explored available TnSeq datasets to identify transcription factors (TFs) that are essential for Mtb survival inside the host. The analysis identified a single TF, Rv1332 (AosR), conserved across actinomycetes with a so‐far uncharacterized function. AosR mitigates phagocyte‐derived oxidative and nitrosative stress, thus promoting mycobacterial growth in the murine lungs and spleen. Oxidative stress induces formation of a single intrasubunit disulphide bond in AosR, which in turn facilitates AosR interaction with an extracytoplasmic‐function sigma factor, SigH. This leads to the specific upregulation of the CysM‐dependent non‐canonical cysteine biosynthesis pathway through an auxiliary intragenic stress‐responsive promoter, an axis critical in detoxifying host‐derived oxidative and nitrosative radicals. Failure to upregulate AosR‐dependent cysteine biosynthesis during the redox stress causes differential expression of 6% of Mtb genes. Our study shows that the AosR‐SigH pathway is critical for detoxifying host‐derived oxidative and nitrosative radicals to enhance Mtb survival in the hostile intracellular environment.
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Feng S, Hong Z, Zhang G, Li J, Tian GB, Zhou H, Huang X. Mycobacterium PPE31 Contributes to Host Cell Death. Front Cell Infect Microbiol 2021; 11:629836. [PMID: 33928042 PMCID: PMC8078103 DOI: 10.3389/fcimb.2021.629836] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/23/2021] [Indexed: 12/03/2022] Open
Abstract
Genome scale mutagenesis identifies many genes required for mycobacterial infectivity and survival, but their contributions and mechanisms of action within the host are poorly understood. Using CRISPR interference, we created a knockdown of ppe31Mm gene in Mycobacterium marinum (M. marinum), which reduced the resistance to acid medium. To further explore the function of PPE31, the ppe31 mutant strain was generated in M. marinum and Mycobacterium tuberculosis (M. tuberculosis), respectively. Macrophages infected with the ppe31Mm mutant strain caused a reduced inflammatory mediator expressions. In addition, macrophages infected with M. marinum Δppe31Mm had decreased host cell death dependent on JNK signaling. Consistent with these results, deletion of ppe31Mtb from M. tuberculosis increased the sensitivity to acid medium and reduced cell death in macrophages. Furthermore, we demonstrate that both ppe31 mutants from M. marinum and M. tuberculosis resulted in reduced survival in macrophages, and the survivability of M. marinum was deceased in zebrafish due to loss of ppe31Mm. Our findings confirm that PPE31 as a virulence associated factor that modulates innate immune responses to mycobacterial infection.
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Affiliation(s)
- Siyuan Feng
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhongshan School of Medicine, Sun Yat-sen University, Zhuhai, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China
| | - Zhongsi Hong
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhongshan School of Medicine, Sun Yat-sen University, Zhuhai, China
| | - Guoliang Zhang
- Shenzhen Key Laboratory of Pathogen and Immunity, National Clinical Research Center for Infectious Disease, State Key Discipline of Infectious Disease, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, Shenzhen, China
| | - Jiachen Li
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhongshan School of Medicine, Sun Yat-sen University, Zhuhai, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China
| | - Guo-Bao Tian
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhongshan School of Medicine, Sun Yat-sen University, Zhuhai, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China
| | - Haibo Zhou
- The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Xi Huang
- Center for Infection and Immunity, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhongshan School of Medicine, Sun Yat-sen University, Zhuhai, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China.,Shenzhen Key Laboratory of Pathogen and Immunity, National Clinical Research Center for Infectious Disease, State Key Discipline of Infectious Disease, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, Shenzhen, China.,The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China.,Sino-French Hoffmann Institute of Immunology, College of Basic Medical Science, Guangzhou Medical University, Guangzhou, China
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Naz S, Dabral S, Nagarajan SN, Arora D, Singh LV, Kumar P, Singh Y, Kumar D, Varshney U, Nandicoori VK. Compromised base excision repair pathway in Mycobacterium tuberculosis imparts superior adaptability in the host. PLoS Pathog 2021; 17:e1009452. [PMID: 33740020 PMCID: PMC8011731 DOI: 10.1371/journal.ppat.1009452] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/31/2021] [Accepted: 03/04/2021] [Indexed: 11/28/2022] Open
Abstract
Tuberculosis caused by Mycobacterium tuberculosis (Mtb) is a significant public health concern, exacerbated by the emergence of drug-resistant TB. To combat the host’s dynamic environment, Mtb encodes multiple DNA repair enzymes that play a critical role in maintaining genomic integrity. Mtb possesses a GC-rich genome, rendering it highly susceptible to cytosine deaminations, resulting in the occurrence of uracils in the DNA. UDGs encoded by ung and udgB initiate the repair; hence we investigated the biological impact of deleting UDGs in the adaptation of pathogen. We generated gene replacement mutants of uracil DNA glycosylases, individually (RvΔung, RvΔudgB) or together (RvΔdKO). The double KO mutant, RvΔdKO exhibited remarkably higher spontaneous mutation rate, in the presence of antibiotics. Interestingly, RvΔdKO showed higher survival rates in guinea pigs and accumulated large number of SNPs as revealed by whole-genome sequence analysis. Competition assays revealed the superior fitness of RvΔdKO over Rv, both in ex vivo and in vivo conditions. We propose that compromised DNA repair results in the accumulation of mutations, and a subset of these drives adaptation in the host. Importantly, this property allowed us to utilize RvΔdKO for the facile identification of drug targets. Mutation in the genome of bacteria contributes to the acquisition of drug resistance. Mutations in bacteria can arise due to exposures to antibiotics, oxidative, reductive, and many other stresses that bacteria encounter in the host. Mtb has multiple DNA repair mechanisms, including a base excision repair pathway to restore the damaged genome. Here we set out to determine the impact of deleting the Uracil DNA base excision pathway on pathogen adaptability to both antibiotic and host induced stresses. Combinatorial mutant of Mtb UDGs showed higher spontaneous rates of mutations when subjected to antibiotic stress and showed higher survival levels in the guinea pig model of infection. Whole-genome sequence analysis showed significant accumulation of SNPs, suggesting that mutations providing survival advantage may have been positively selected. We also showed that double mutant of Mtb UDGs would be an excellent means to identify antibiotic targets in the bacteria. Competition experiments wherein we pitted wild type and double mutant against each other demonstrated that double mutant has a decisive edge over the wild type. Together, data suggest that the absence of a base excision repair pathway leads to higher mutations and provides a survival advantage under stress. They could be an invaluable tool for identifying targets of new antibiotics.
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Affiliation(s)
- Saba Naz
- Signal Transduction Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
- Department of Zoology, University of Delhi, Delhi, India
| | - Shruti Dabral
- Cellular Immunology Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | | | - Divya Arora
- Signal Transduction Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
| | - Lakshya Veer Singh
- Cellular Immunology Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - Pradeep Kumar
- Department of Microbiology & Cell Biology, Indian Institute of Sciences, Bangalore, India
| | - Yogendra Singh
- Department of Zoology, University of Delhi, Delhi, India
| | - Dhiraj Kumar
- Cellular Immunology Group, International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - Umesh Varshney
- Department of Microbiology & Cell Biology, Indian Institute of Sciences, Bangalore, India
- * E-mail: (UV); (VKN)
| | - Vinay Kumar Nandicoori
- Signal Transduction Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India
- * E-mail: (UV); (VKN)
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Naz S, Singh Y, Nandicoori VK. Deletion of serine/threonine-protein kinase pknL from Mycobacterium tuberculosis reduces the efficacy of isoniazid and ethambutol. Tuberculosis (Edinb) 2021; 128:102066. [PMID: 33690080 DOI: 10.1016/j.tube.2021.102066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/16/2021] [Accepted: 02/21/2021] [Indexed: 02/07/2023]
Abstract
Serine/threonine-protein kinases in Mycobacterium tuberculosis (Mtb) form a preeminent regulatory system required to establish and maintain the infection in the host. Herein, we sought to decipher the biological role of PknL with the help of a gene replacement mutant RvΔpknL. Deletion of pknL results in the compromised growth under redox stress. The mutant showed significant survival defects in peritoneal macrophages, a significant decrease in the ability to establish infections and disseminate to the spleen in the murine model of infection. While the absence of pknL has no impact on either MIC or CFUs of ciprofloxacin and rifampicin treated bacilli, it increases the survival ~1.5-2.5 log fold upon isoniazid or ethambutol treatment. Collectively, data suggests that PknL aids in combating stress conditions in vitro, ex vivo, and in vivo and reduces the efficacy of isoniazid and ethambutol.
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Affiliation(s)
- Saba Naz
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India; Department of Zoology, University of Delhi, Delhi, 110007, India
| | - Yogendra Singh
- Department of Zoology, University of Delhi, Delhi, 110007, India
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Rens C, Chao JD, Sexton DL, Tocheva EI, Av-Gay Y. Roles for phthiocerol dimycocerosate lipids in Mycobacterium tuberculosis pathogenesis. MICROBIOLOGY-SGM 2021; 167. [PMID: 33629944 DOI: 10.1099/mic.0.001042] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The success of Mycobacterium tuberculosis as a pathogen is well established: tuberculosis is the leading cause of death by a single infectious agent worldwide. The threat of multi- and extensively drug-resistant bacteria has renewed global concerns about this pathogen and understanding its virulence strategies will be essential in the fight against tuberculosis. The current review will focus on phthiocerol dimycocerosates (PDIMs), a long-known and well-studied group of complex lipids found in the M. tuberculosis cell envelope. Numerous studies show a role for PDIMs in several key steps of M. tuberculosis pathogenesis, with recent studies highlighting its involvement in bacterial virulence, in association with the ESX-1 secretion system. Yet, the mechanisms by which PDIMs help M. tuberculosis to control macrophage phagocytosis, inhibit phagosome acidification and modulate host innate immunity, remain to be fully elucidated.
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Affiliation(s)
- Céline Rens
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Joseph D Chao
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Danielle L Sexton
- Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
| | - Elitza I Tocheva
- Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
| | - Yossef Av-Gay
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada.,Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
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Smyth R, Berton S, Rajabalee N, Chan T, Sun J. Protein Kinase R Restricts the Intracellular Survival of Mycobacterium tuberculosis by Promoting Selective Autophagy. Front Microbiol 2021; 11:613963. [PMID: 33552025 PMCID: PMC7862720 DOI: 10.3389/fmicb.2020.613963] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 12/30/2020] [Indexed: 12/18/2022] Open
Abstract
Tuberculosis (TB) is a deadly infectious lung disease caused by the pathogenic bacterium Mycobacterium tuberculosis (Mtb). The identification of macrophage signaling proteins exploited by Mtb during infection will enable the development of alternative host-directed therapies (HDT) for TB. HDT strategies will boost host immunity to restrict the intracellular replication of Mtb and therefore hold promise to overcome antimicrobial resistance, a growing crisis in TB therapy. Protein Kinase R (PKR) is a key host sensor that functions in the cellular antiviral response. However, its role in defense against intracellular bacterial pathogens is not clearly defined. Herein, we demonstrate that expression and activation of PKR is upregulated in macrophages infected with Mtb. Immunological profiling of human THP-1 macrophages that overexpress PKR (THP-PKR) showed increased production of IP-10 and reduced production of IL-6, two cytokines that are reported to activate and inhibit IFNγ-dependent autophagy, respectively. Indeed, sustained expression and activation of PKR reduced the intracellular survival of Mtb, an effect that could be enhanced by IFNγ treatment. We further demonstrate that the enhanced anti-mycobacterial activity of THP-PKR macrophages is mediated by a mechanism dependent on selective autophagy, as indicated by increased levels of LC3B-II that colocalize with intracellular Mtb. Consistent with this mechanism, inhibition of autophagolysosome maturation with bafilomycin A1 abrogated the ability of THP-PKR macrophages to limit replication of Mtb, whereas pharmacological activation of autophagy enhanced the anti-mycobacterial effect of PKR overexpression. As such, PKR represents a novel and attractive host target for development of HDT for TB, and our data suggest value in the design of more specific and potent activators of PKR.
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Affiliation(s)
- Robin Smyth
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Stefania Berton
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Nusrah Rajabalee
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Therese Chan
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Jim Sun
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Centre for Infection, Immunity and Inflammation, University of Ottawa, Ottawa, ON, Canada
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Sterilization by Adaptive Immunity of a Conditionally Persistent Mutant of Mycobacterium tuberculosis. mBio 2021; 12:mBio.02391-20. [PMID: 33468684 PMCID: PMC7845640 DOI: 10.1128/mbio.02391-20] [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] [Indexed: 11/29/2022] Open
Abstract
The bacterial pathogen Mycobacterium tuberculosis can enter into a persistent state in which M. tuberculosis can evade host immunity, thereby reducing the effectiveness of current tuberculosis vaccines. Understanding the factors that contribute to persistence would enable the rational design of vaccines effective against persisters. Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, can enter into a persistent state that confers resistance to antibacterial agents. Many observations suggest that persistent M. tuberculosis cells also evade the antimycobacterial immune mechanisms, thereby reducing the effectiveness of the current tuberculosis vaccine. Understanding the factors that contribute to persistence may enable the rational design of vaccines that stimulate effective immune killing mechanisms against persister cells. Independent mutations targeting the methionine and arginine biosynthetic pathways are bactericidal for M. tuberculosis in mice. However, in this study, we discovered that the addition of leucine and pantothenate auxotrophy altered the bactericidality of methionine auxotrophy. Whereas the leucine/pantothenate/methionine auxotrophic M. tuberculosis strain H37Rv ΔleuCD ΔpanCD ΔmetA was eliminated in immunocompetent mice, this strain persisted in multiple organs of immunodeficient Rag1−/− mice for at least a year. In contrast, the leucine/pantothenate/arginine auxotroph H37Rv ΔleuCD ΔpanCD ΔargB was eliminated in both immunocompetent and immunodeficient Rag1−/− mice. Our results showed that leucine and pantothenate starvation metabolically blocked the sterilization mechanisms of methionine starvation but not those of arginine starvation. These triple-auxotrophic strains should be invaluable tools for unravelling the bacterial and host factors that enable persistence and for vaccine development studies to assess the efficacy of vaccines that boost immune recognition of M. tuberculosis in the persistent state. The sterilization of the ΔleuCD ΔpanCD ΔmetA auxotroph in immunocompetent mice, but not in mice lacking an adaptive immune response, could provide a new system for studying the antimycobacterial killing mechanisms of adaptive immunity.
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Lack of Specificity of Phenotypic Screens for Inhibitors of the Mycobacterium tuberculosis FAS-II System. Antimicrob Agents Chemother 2020; 65:AAC.01914-20. [PMID: 33139282 DOI: 10.1128/aac.01914-20] [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: 09/04/2020] [Accepted: 10/26/2020] [Indexed: 11/20/2022] Open
Abstract
Phenotypic screening of inhibitors of the essential Mycobacterium tuberculosis FAS-II dehydratase HadAB led to the identification of GSK3011724A, a compound previously reported to inhibit the condensation step of FAS-II. Whole-cell-based and cell-free assays confirmed the lack of activity of GSK3011724A against the dehydratase despite evidence of cross-resistance between GSK3011724A and HadAB inhibitors. The nature of the resistance mechanisms is suggestive of alterations in the FAS-II interactome reducing access of GSK3011724A to KasA.
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