1
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Haller YA, Jiang J, Wan Z, Childress A, Wang S, Haydel SE. M. tuberculosis PrrA binds the dosR promoter and regulates mycobacterial adaptation to hypoxia. Tuberculosis (Edinb) 2024; 148:102531. [PMID: 38885567 DOI: 10.1016/j.tube.2024.102531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/30/2024] [Accepted: 06/05/2024] [Indexed: 06/20/2024]
Abstract
The PrrAB two-component system (TCS) is essential for Mycobacterium tuberculosis viability. Previously, it was demonstrated that PrrA binds DNA in the absence of PrrB-mediated transphosphorylation and that non-cognate serine/threonine-kinases phosphorylate PrrA threonine-6 (T6). Therefore, we investigated the differential binding affinity and regulatory properties of the M. tuberculosis-derived wild-type PrrA, PrrA phosphomimetic (D58E, T6E), and PrrA phosphoablative (D58A, T6A) proteins with the prrAMtb, dosRMtb, and cydAMtb genes. While we hypothesized greater DNA binding affinity and more pronounced regulation by PrrA phosphomimetic variants, recombinant, wild-type PrrAMtb bound DNA with greatest affinity. Collectively, wild-type PrrAMtb recombinant protein displayed the highest binding affinity to the dosRMtb promoter (KD 3.46 ± 2.09 nM), followed by the prrAMtb promoter (KD 9.00 ± 2.66 nM). To establish PrrAMtb regulatory activity, we constructed M. smegmatis ΔprrABMsmeg::prrAMtb strains with each of the PrrAMtb variants and extrachromosomal prrAMtb, dosRMtb, and cydAMtb promoter-mCherry reporter fusions. Our findings showed that PrrAMtb is autoregulatory and induces dosRMtb expression only during in vitro, hypoxic growth. Combined expression of prrABMtb in M. smegmatis ΔprrAB significantly induced cydAMtb promoter-mCherry expression. Our studies advanced the understanding of PrrA function and PrrAB phosphorylation-mediated regulatory mechanisms and control of mycobacterial dosR and cydA hypoxic and low-oxygen responsive genes.
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Affiliation(s)
- Yannik A Haller
- School of Life Sciences, Arizona State University, Tempe, AZ, USA; Biodesign Institute Center for Bioelectronics and Biosensors, Arizona State University, Tempe, AZ, USA
| | - Jiapei Jiang
- Biodesign Institute Center for Bioelectronics and Biosensors, Arizona State University, Tempe, AZ, USA; School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
| | - Zijian Wan
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA; School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, USA
| | - Alexia Childress
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Shaopeng Wang
- Biodesign Institute Center for Bioelectronics and Biosensors, Arizona State University, Tempe, AZ, USA; School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
| | - Shelley E Haydel
- School of Life Sciences, Arizona State University, Tempe, AZ, USA; Biodesign Institute Center for Bioelectronics and Biosensors, Arizona State University, Tempe, AZ, USA.
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2
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Kim NK, Baek JE, Lee YJ, Oh Y, Oh JI. Rel-dependent decrease in the expression of ribosomal protein genes by inhibition of the respiratory electron transport chain in Mycobacterium smegmatis. Front Microbiol 2024; 15:1448277. [PMID: 39188315 PMCID: PMC11345224 DOI: 10.3389/fmicb.2024.1448277] [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: 06/13/2024] [Accepted: 07/24/2024] [Indexed: 08/28/2024] Open
Abstract
In this study, we demonstrated that both the expression of most ribosomal protein genes and the amount of ribosomes were decreased in the Δaa 3 mutant of Mycobacterium smegmatis, in which the major terminal oxidase (aa 3 cytochrome c oxidase) of the respiratory electron transport chain (ETC) is inactivated, compared to those in the wild-type strain. Deletion of the rel gene encoding the major (p)ppGpp synthetase in the background of the Δaa 3 mutant restored the reduced expression of ribosomal protein genes, suggesting that inhibition of the respiratory ETC leads to the Rel-dependent stringent response (SR) in this bacterium. Both a decrease in the expression of ribosomal protein genes by overexpression of rel and the increased expression of rel in the Δaa 3 mutant relative to the wild-type strain support the Rel-dependent induction of SR in the Δaa 3 mutant. We also demonstrated that the expression of ribosomal protein genes was decreased in M. smegmatis exposed to respiration-inhibitory conditions, such as KCN and bedaquiline treatment, null mutation of the cytochrome bcc 1 complex, and hypoxia. The MprBA-SigE-SigB regulatory pathway was implicated in both the increased expression of rel and the decreased expression of ribosomal protein genes in the Δaa 3 mutant of M. smegmatis.
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Affiliation(s)
- Na-Kyeong Kim
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Jong-Eun Baek
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Ye-Jin Lee
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Yuna Oh
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Jeong-Il Oh
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
- Microbiological Resource Research Institute, Pusan National University, Busan, Republic of Korea
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3
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Davis NK, Chionh YH, McBee ME, Hia F, Ma D, Cui L, Sharaf ML, Cai WM, Jumpathong W, Levine SS, Alonso S, Dedon PC. Facile metabolic reprogramming distinguishes mycobacterial adaptation to hypoxia and starvation: ketosis drives starvation-induced persistence in M. bovis BCG. Commun Biol 2024; 7:866. [PMID: 39009734 PMCID: PMC11250799 DOI: 10.1038/s42003-024-06562-2] [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: 01/08/2024] [Accepted: 07/05/2024] [Indexed: 07/17/2024] Open
Abstract
Mycobacteria adapt to infection stresses by entering a reversible non-replicating persistence (NRP) with slow or no cell growth and broad antimicrobial tolerance. Hypoxia and nutrient deprivation are two well-studied stresses commonly used to model the NRP, yet little is known about the molecular differences in mycobacterial adaptation to these distinct stresses that lead to a comparable NRP phenotype. Here we performed a multisystem interrogation of the Mycobacterium bovis BCG (BCG) starvation response, which revealed a coordinated metabolic shift away from the glycolysis of nutrient-replete growth to depletion of lipid stores, lipolysis, and fatty acid ß-oxidation in NRP. This contrasts with BCG's NRP hypoxia response involving a shift to cholesterol metabolism and triglyceride storage. Our analysis reveals cryptic metabolic vulnerabilities of the starvation-induced NRP state, such as their newfound hypersensitivity to H2O2. These observations pave the way for developing precision therapeutics against these otherwise drug refractory pathogens.
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Affiliation(s)
- Nick K Davis
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yok Hian Chionh
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- GenScript Biotech (Singapore) Pte. Ltd, Singapore, Singapore
| | - Megan E McBee
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Fabian Hia
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Duanduan Ma
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Liang Cui
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Mariam Lucila Sharaf
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
- BioNTech SE An der Goldgrube, Mainz, Germany
| | - Weiling Maggie Cai
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- British High Commission, Singapore, Singapore
| | - Watthanachai Jumpathong
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Chemical Biology Program, Chulabhorn Graduate Institute, Bangkok, Thailand
| | - Stuart S Levine
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sylvie Alonso
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Peter C Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore.
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4
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McKay LS, Spandrio AR, Johnson RM, Sobran MA, Marlatt SA, Mote KB, Dedloff MR, Nash ZM, Julio SM, Cotter PA. Cytochrome oxidase requirements in Bordetella reveal insights into evolution towards life in the mammalian respiratory tract. PLoS Pathog 2024; 20:e1012084. [PMID: 38976749 PMCID: PMC11257404 DOI: 10.1371/journal.ppat.1012084] [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: 02/29/2024] [Revised: 07/18/2024] [Accepted: 06/17/2024] [Indexed: 07/10/2024] Open
Abstract
Little is known about oxygen utilization during infection by bacterial respiratory pathogens. The classical Bordetella species, including B. pertussis, the causal agent of human whooping cough, and B. bronchiseptica, which infects nearly all mammals, are obligate aerobes that use only oxygen as the terminal electron acceptor for electron transport-coupled oxidative phosphorylation. B. bronchiseptica, which occupies many niches, has eight distinct cytochrome oxidase-encoding loci, while B. pertussis, which evolved from a B. bronchiseptica-like ancestor but now survives exclusively in and between human respiratory tracts, has only three functional cytochrome oxidase-encoding loci: cydAB1, ctaCDFGE1, and cyoABCD1. To test the hypothesis that the three cytochrome oxidases encoded within the B. pertussis genome represent the minimum number and class of cytochrome oxidase required for respiratory infection, we compared B. bronchiseptica strains lacking one or more of the eight possible cytochrome oxidases in vitro and in vivo. No individual cytochrome oxidase was required for growth in ambient air, and all three of the cytochrome oxidases conserved in B. pertussis were sufficient for growth in ambient air and low oxygen. Using a high-dose, large-volume persistence model and a low-dose, small-volume establishment of infection model, we found that B. bronchiseptica producing only the three B. pertussis-conserved cytochrome oxidases was indistinguishable from the wild-type strain for infection. We also determined that CyoABCD1 is sufficient to cause the same level of bacterial burden in mice as the wild-type strain and is thus the primary cytochrome oxidase required for murine infection, and that CydAB1 and CtaCDFGE1 fulfill auxiliary roles or are important for aspects of infection we have not assessed, such as transmission. Our results shed light on the environment at the surface of the ciliated epithelium, respiration requirements for bacteria that colonize the respiratory tract, and the evolution of virulence in bacterial pathogens.
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Affiliation(s)
- Liliana S. McKay
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Alexa R. Spandrio
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Richard M. Johnson
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - M. Ashley Sobran
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Sara A. Marlatt
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Katlyn B. Mote
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Margaret R. Dedloff
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Zachary M. Nash
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Steven M. Julio
- Department of Biology, Westmont College, Santa Barbara, California, United States of America
| | - Peggy A. Cotter
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, North Carolina, United States of America
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5
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Kalia NP, Singh S, Hards K, Cheung CY, Sviriaeva E, Banaei-Esfahani A, Aebersold R, Berney M, Cook GM, Pethe K. M. tuberculosis relies on trace oxygen to maintain energy homeostasis and survive in hypoxic environments. Cell Rep 2023; 42:112444. [PMID: 37115669 DOI: 10.1016/j.celrep.2023.112444] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 03/15/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
The bioenergetic mechanisms by which Mycobacterium tuberculosis survives hypoxia are poorly understood. Current models assume that the bacterium shifts to an alternate electron acceptor or fermentation to maintain membrane potential and ATP synthesis. Counterintuitively, we find here that oxygen itself is the principal terminal electron acceptor during hypoxic dormancy. M. tuberculosis can metabolize oxygen efficiently at least two orders of magnitude below the concentration predicted to occur in hypoxic lung granulomas. Despite a difference in apparent affinity for oxygen, both the cytochrome bcc:aa3 and cytochrome bd oxidase respiratory branches are required for hypoxic respiration. Simultaneous inhibition of both oxidases blocks oxygen consumption, reduces ATP levels, and kills M. tuberculosis under hypoxia. The capacity of mycobacteria to scavenge trace levels of oxygen, coupled with the absence of complex regulatory mechanisms to achieve hierarchal control of the terminal oxidases, may be a key determinant of long-term M. tuberculosis survival in hypoxic lung granulomas.
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Affiliation(s)
- Nitin Pal Kalia
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore; Department of Biological Sciences, National Institute of Pharmaceutical Education and Research (NIPER-H) Hyderabad, Hyderabad, Telangana 500037, India
| | - Samsher Singh
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore
| | - Kiel Hards
- 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, Auckland 92019, New Zealand
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Ekaterina Sviriaeva
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore
| | - Amir Banaei-Esfahani
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, 8057 Zurich, Switzerland
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, 8057 Zurich, Switzerland; Faculty of Science, University of Zurich, 8057 Zurich, Switzerland
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - 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, Auckland 92019, New Zealand.
| | - Kevin Pethe
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore; Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; National Centre for Infectious Diseases, Singapore 308442, Singapore.
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6
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Kelam LM, Wani MA, Dhaked DK. An update on ATP synthase inhibitors: A unique target for drug development in M. tuberculosis. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 180-181:87-104. [PMID: 37105260 DOI: 10.1016/j.pbiomolbio.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023]
Abstract
ATP synthase is a key protein in the oxidative phosphorylation process, as it aids in the effective production of ATP (Adenosine triphosphate) in all life's of kingdoms. ATP synthases have distinctive properties that contribute to efficient ATP synthesis. The ATP synthase of mycobacterium is of special relevance since it has been identified as a target for potential anti-TB molecules, especially Bedaquiline (BDQ). Better knowledge of how mycobacterial ATP synthase functions and its peculiar characteristics will aid in our understanding of bacterial energy metabolism adaptations. Furthermore, identifying and understanding the important distinctions between human ATP synthase and bacterial ATP synthase may provide insight into the design and development of inhibitors that target specific ATP synthase. In recent years, many potential candidates targeting the ATP synthase of mycobacterium have been developed. In this review, we discuss the druggable targets of the Electron transport chain (ETC) and recently identified potent inhibitors (including clinical molecules) from 2015 to 2022 of diverse classes that target ATP synthase of M. tuberculosis.
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Affiliation(s)
- Lakshmi Mounika Kelam
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER)-Kolkata, Chunilal Bhawan, 168 Maniktala Main Road, Kolkata, 700054, West Bengal, India
| | - Mushtaq Ahmad Wani
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER)-Kolkata, Chunilal Bhawan, 168 Maniktala Main Road, Kolkata, 700054, West Bengal, India
| | - Devendra K Dhaked
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER)-Kolkata, Chunilal Bhawan, 168 Maniktala Main Road, Kolkata, 700054, West Bengal, India.
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7
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Oh Y, Lee HN, Ko EM, Jeong JA, Park SW, Oh JI. Mycobacterial Regulatory Systems Involved in the Regulation of Gene Expression Under Respiration-Inhibitory Conditions. J Microbiol 2023; 61:297-315. [PMID: 36847970 DOI: 10.1007/s12275-023-00026-8] [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: 12/29/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 03/01/2023]
Abstract
Mycobacterium tuberculosis is the causative agent of tuberculosis. M. tuberculosis can survive in a dormant state within the granuloma, avoiding the host-mounting immune attack. M. tuberculosis bacilli in this state show increased tolerance to antibiotics and stress conditions, and thus the transition of M. tuberculosis to the nonreplicating dormant state acts as an obstacle to tuberculosis treatment. M. tuberculosis in the granuloma encounters hostile environments such as hypoxia, nitric oxide, reactive oxygen species, low pH, and nutrient deprivation, etc., which are expected to inhibit respiration of M. tuberculosis. To adapt to and survive in respiration-inhibitory conditions, it is required for M. tuberculosis to reprogram its metabolism and physiology. In order to get clues to the mechanism underlying the entry of M. tuberculosis to the dormant state, it is important to understand the mycobacterial regulatory systems that are involved in the regulation of gene expression in response to respiration inhibition. In this review, we briefly summarize the information regarding the regulatory systems implicated in upregulation of gene expression in mycobacteria exposed to respiration-inhibitory conditions. The regulatory systems covered in this review encompass the DosSR (DevSR) two-component system, SigF partner switching system, MprBA-SigE-SigB signaling pathway, cAMP receptor protein, and stringent response.
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Affiliation(s)
- Yuna Oh
- Department of Integrated Biological Science, Pusan National University, Busan, 46241, Republic of Korea
| | - Ha-Na Lee
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Eon-Min Ko
- Division of Bacterial Disease Research, Center for Infectious Disease Research, Korea Disease Control and Prevention Agency, National Institute of Infectious Diseases, National Institute of Health, Osong, 28159, Republic of Korea
| | - Ji-A Jeong
- Division of Bacterial Disease Research, Center for Infectious Disease Research, Korea Disease Control and Prevention Agency, National Institute of Infectious Diseases, National Institute of Health, Osong, 28159, Republic of Korea
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Jeong-Il Oh
- Department of Integrated Biological Science, Pusan National University, Busan, 46241, Republic of Korea. .,Microbiological Resource Research Institute, Pusan National University, Busan, 46241, Republic of Korea.
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8
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Response of Mycobacterium smegmatis to the Cytochrome bcc Inhibitor Q203. Int J Mol Sci 2022; 23:ijms231810331. [PMID: 36142240 PMCID: PMC9498996 DOI: 10.3390/ijms231810331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
For the design of next-generation tuberculosis chemotherapy, insight into bacterial defence against drugs is required. Currently, targeting respiration has attracted strong attention for combatting drug-resistant mycobacteria. Q203 (telacebec), an inhibitor of the cytochrome bcc complex in the mycobacterial respiratory chain, is currently evaluated in phase-2 clinical trials. Q203 has bacteriostatic activity against M. tuberculosis, which can be converted to bactericidal activity by concurrently inhibiting an alternative branch of the mycobacterial respiratory chain, cytochrome bd. In contrast, non-tuberculous mycobacteria, such as Mycobacterium smegmatis, show only very little sensitivity to Q203. In this report, we investigated factors that M. smegmatis employs to adapt to Q203 in the presence or absence of a functional cytochrome bd, especially regarding its terminal oxidases. In the presence of a functional cytochrome bd, M. smegmatis responds to Q203 by increasing the expression of cytochrome bcc as well as of cytochrome bd, whereas a M. smegmatisbd-KO strain adapted to Q203 by increasing the expression of cytochrome bcc. Interestingly, single-cell studies revealed cell-to-cell variability in drug adaptation. We also investigated the role of a putative second cytochrome bd isoform postulated for M. smegmatis. Although this putative isoform showed differential expression in response to Q203 in the M. smegmatisbd-KO strain, it did not display functional features similar to the characterised cytochrome bd variant.
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9
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McNeil MB, Cheung CY, Waller NJE, Adolph C, Chapman CL, Seeto NEJ, Jowsey W, Li Z, Hameed HMA, Zhang T, Cook GM. Uncovering interactions between mycobacterial respiratory complexes to target drug-resistant Mycobacterium tuberculosis. Front Cell Infect Microbiol 2022; 12:980844. [PMID: 36093195 PMCID: PMC9461714 DOI: 10.3389/fcimb.2022.980844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/03/2022] [Indexed: 11/24/2022] Open
Abstract
Mycobacterium tuberculosis remains a leading cause of infectious disease morbidity and mortality for which new drug combination therapies are needed. Mycobacterial bioenergetics has emerged as a promising space for the development of novel therapeutics. Further to this, unique combinations of respiratory inhibitors have been shown to have synergistic or synthetic lethal interactions, suggesting that combinations of bioenergetic inhibitors could drastically shorten treatment times. Realizing the full potential of this unique target space requires an understanding of which combinations of respiratory complexes, when inhibited, have the strongest interactions and potential in a clinical setting. In this review, we discuss (i) chemical-interaction, (ii) genetic-interaction and (iii) chemical-genetic interaction studies to explore the consequences of inhibiting multiple mycobacterial respiratory components. We provide potential mechanisms to describe the basis for the strongest interactions. Finally, whilst we place an emphasis on interactions that occur with existing bioenergetic inhibitors, by highlighting interactions that occur with alternative respiratory components we envision that this information will provide a rational to further explore alternative proteins as potential drug targets and as part of unique drug combinations.
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Affiliation(s)
- Matthew B. McNeil
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins, Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- *Correspondence: Matthew B. McNeil, ; Gregory M. Cook,
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Natalie J. E. Waller
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cara Adolph
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cassandra L. Chapman
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Noon E. J. Seeto
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - William Jowsey
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Zhengqiu Li
- School of Pharmacy, Jinan University, Guangzhou, China
| | - H. M. Adnan Hameed
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- China-New Zealand Joint Laboratory of Biomedicine and Health, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- Guangdong-Hong Kong-Macau Joint Laboratory of Respiratory Infectious Diseases, Guangzhou, China
- University of Chinese Academy of Sciences (UCAS), Beijing, China
| | - Tianyu Zhang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- China-New Zealand Joint Laboratory of Biomedicine and Health, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- Guangdong-Hong Kong-Macau Joint Laboratory of Respiratory Infectious Diseases, Guangzhou, China
- University of Chinese Academy of Sciences (UCAS), Beijing, China
| | - Gregory M. Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins, Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- *Correspondence: Matthew B. McNeil, ; Gregory M. Cook,
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10
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Activation of the SigE-SigB signaling pathway by inhibition of the respiratory electron transport chain and its effect on rifampicin resistance in Mycobacterium smegmatis. J Microbiol 2022; 60:935-947. [DOI: 10.1007/s12275-022-2202-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 10/16/2022]
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11
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Swaminath S, Pradhan A, Nair RR, Ajitkumar P. Deletion of rifampicin-inactivating mono-ADP-ribosyl transferase gene of Mycobacterium smegmatis globally altered gene expression profile that favoured increase in ROS levels and thereby antibiotic resister generation. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100142. [PMID: 35909599 PMCID: PMC9325912 DOI: 10.1016/j.crmicr.2022.100142] [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] [Received: 11/28/2021] [Revised: 05/21/2022] [Accepted: 05/29/2022] [Indexed: 10/31/2022] Open
Abstract
Physiological role of mono-ADP-ribosyl transferase (Arr) of Mycobacterium smegmatis revealed. Arr is required to maintain ROS levels in actively growing M. smegmatis. Arr influences gene expression at global level in several pathways. Expression of electron transfer, antioxidation, and DNA repair genes are influenced by Arr. Arr is required to maintain an optimal oxidative and metabolic status.
The physiological role of mono-ADP-ribosyl transferase (Arr) of Mycobacterium smegmatis, which inactivates rifampicin, remains unclear. An earlier study reported increased expression of arr during oxidative stress and DNA damage. This suggested a role for Arr in the oxidative status of the cell and its associated effect on DNA damage. Since reactive oxygen species (ROS) influence oxidative status, we investigated whether Arr affected ROS levels in M. smegmatis. Significantly elevated levels of superoxide and hydroxyl radical were found in the mid-log phase (MLP) cultures of the arr knockout strain (arr-KO) as compared those in the wild-type strain (WT). Complementation of arr-KO with expression from genomically integrated arr under its native promoter restored the levels of ROS equivalent to that in WT. Due to the inherently high ROS levels in the actively growing arr-KO, rifampicin resisters with rpoB mutations could be selected at 0 hr of exposure itself against rifampicin, unlike in the WT where the resisters emerged at 12th hr of rifampicin exposure. Microarray analysis of the actively growing cultures of arr-KO revealed significantly high levels of expression of genes from succinate dehydrogenase I and NADH dehydrogenase I operons, which would have contributed to the increased superoxide levels. In parallel, expression of specific DNA repair genes was significantly decreased, favouring retention of the mutations inflicted by the ROS. Expression of several metabolic pathway genes also was significantly altered. These observations revealed that Arr was required for maintaining a gene expression profile that would provide optimum levels of ROS and DNA repair system in the actively growing M. smegmatis.
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12
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Cardoso NC, Chibale K, Singh V. Implications of Mycobacterium tuberculosis Metabolic Adaptability on Drug Discovery and Development. ACS Infect Dis 2022; 8:414-421. [PMID: 35175727 DOI: 10.1021/acsinfecdis.1c00627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tuberculosis remains a global health threat that is being exacerbated by the increase in infections attributed to drug resistant Mycobacterium tuberculosis. To combat this, there has been a surge in drug discovery programs to develop new, potent compounds and identify promising drug targets in the pathogen. Two areas of M. tuberculosis biology that have emerged as rich sources of potential novel drug targets are cell wall biosynthesis and energy metabolism. Both processes are important for survival of M. tuberculosis under replicating and nonreplicating conditions. However, both processes are also inherently adaptable under different conditions. Furthermore, cell wall biosynthesis is energy intensive and, thus, reliant on an efficiently functioning energy production system. This Perspective focuses on the interplay between cell wall biosynthesis and energy metabolism in M. tuberculosis, how adaptations in one pathway may affect the other, and what consequences this could have for drug discovery and development and the identification of novel drug targets.
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Affiliation(s)
- Nicole C. Cardoso
- Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch 7701, South Africa
| | - Kelly Chibale
- Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch 7701, South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | - Vinayak Singh
- Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch 7701, South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
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13
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Multiplexed transcriptional repression identifies a network of bactericidal interactions between mycobacterial respiratory complexes. iScience 2022; 25:103573. [PMID: 34984329 PMCID: PMC8692989 DOI: 10.1016/j.isci.2021.103573] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/07/2021] [Accepted: 12/02/2021] [Indexed: 12/28/2022] Open
Abstract
Mycobacterium tuberculosis remains a leading cause of infectious disease morbidity and mortality for which new drug combination therapies are needed. Combinations of respiratory inhibitors can have synergistic or synthetic lethal interactions with sterilizing activity, suggesting that regimens with multiple bioenergetic inhibitors could shorten treatment times. However, realizing this potential requires an understanding of which combinations of respiratory complexes, when inhibited, have the strongest consequences on bacterial growth and viability. Here we have used multiplex CRISPR interference (CRISPRi) and Mycobacterium smegmatis as a physiological and molecular model for mycobacterial respiration to identify interactions between respiratory complexes. In this study, we identified synthetic lethal and synergistic interactions between respiratory complexes and demonstrated how the engineering of CRISPRi-guide sequences can be used to further explore networks of interacting gene pairs. These results provide fundamental insights into the functions of and interactions between bioenergetic complexes and the utility of CRISPRi in designing drug combinations.
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14
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Younus I, Kochkina S, Choi CC, Sun W, Ford RC. ATP-Binding Cassette Transporters: Snap-on Complexes? Subcell Biochem 2022; 99:35-82. [PMID: 36151373 DOI: 10.1007/978-3-031-00793-4_2] [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] [Indexed: 06/16/2023]
Abstract
ATP-binding cassette (ABC) transporters are one of the largest families of membrane proteins in prokaryotic organisms. Much is now understood about the structure of these transporters and many reviews have been written on that subject. In contrast, less has been written on the assembly of ABC transporter complexes and this will be a major focus of this book chapter. The complexes are formed from two cytoplasmic subunits that are highly conserved (in terms of their primary and three-dimensional structures) across the whole family. These ATP-binding subunits give rise to the name of the family. They must assemble with two transmembrane subunits that will typically form the permease component of the transporter. The transmembrane subunits have been found to be surprisingly diverse in structure when the whole family is examined, with seven distinct folds identified so far. Hence nucleotide-binding subunits appear to have been bolted on to a variety of transmembrane platforms during evolution, leading to a greater variety in function. Furthermore, many importers within the family utilise a further external substrate-binding component to trap scarce substrates and deliver them to the correct permease components. In this chapter, we will discuss whether assembly of the various ABC transporter subunits occurs with high fidelity within the crowded cellular environment and whether promiscuity in assembly of transmembrane and cytoplasmic components can occur. We also discuss the new AlphaFold protein structure prediction tool which predicts a new type of transmembrane domain fold within the ABC transporters that is associated with cation exporters of bacteria and plants.
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Affiliation(s)
- Iqra Younus
- Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Sofia Kochkina
- Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Cheri C Choi
- Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Wenjuan Sun
- Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, UK
| | - Robert C Ford
- Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, UK.
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15
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Sindhu T, Debnath P. Cytochrome bc1-aa3 oxidase supercomplex as emerging and potential drug target against tuberculosis. Curr Mol Pharmacol 2021; 15:380-392. [PMID: 34602044 DOI: 10.2174/1874467214666210928152512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/26/2021] [Accepted: 06/06/2021] [Indexed: 11/22/2022]
Abstract
The cytochrome bc1-aa3 supercomplex plays an essential role in the cellular respiratory system of Mycobacterium Tuberculosis. It transfers electrons from menaquinol to cytochrome aa3 (Complex IV) via cytochrome bc1 (Complex III), which reduces the oxygen. The electron transfer from a variety of donors into oxygen through the respiratory electron transport chain is essential to pump protons across the membrane creating an electrochemical transmembrane gradient (proton motive force, PMF) that regulates the synthesis of ATP via the oxidative phosphorylation process. Cytochrome bc1-aa3 supercomplex in M. tuberculosis is, therefore, a major drug target for antibiotic action. In recent years, several respiratory chain components have been targeted for developing new candidate drugs, illustrating the therapeutic potential of obstructing energy conversion of M. tuberculosis. The recently available cryo-EM structure of mycobacterial cytochrome bc1-aa3 supercomplex with open and closed conformations has opened new avenues for understanding its structure and function for developing more effective, new therapeutics against pulmonary tuberculosis. In this review, we discuss the role and function of several components, subunits, and drug targeting elements of the supercomplex cytochrome bc1-aa3, and its potential inhibitors in detail.
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Affiliation(s)
- Thangaraj Sindhu
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka. India
| | - Pal Debnath
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka. India
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16
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Patil V, Jain V. Understanding Metabolic Remodeling in Mycobacterium smegmatis to Overcome Energy Exigency and Reductive Stress Under Energy-Compromised State. Front Microbiol 2021; 12:722229. [PMID: 34539614 PMCID: PMC8440910 DOI: 10.3389/fmicb.2021.722229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/11/2021] [Indexed: 12/04/2022] Open
Abstract
Mycobacteria such as Mycobacterium tuberculosis, the causative agent of tuberculosis that annually kills several million people worldwide, and Mycobacterium smegmatis, the non-pathogenic fast-growing mycobacteria, require oxidative phosphorylation to meet their energy requirements. We have previously shown that deletion of one of the two copies of atpD gene that codes for the ATP synthase β-subunit establishes an energy-compromised state in M. smegmatis. Here we report that upon such deletion, a major routing of electron flux occurs through the less energy-efficient complexes of its respiratory chain. ΔatpD bacterium also shows an increased reduced state which is further confirmed by the overexpression of WhiB3, a major redox sensor. We show a substantial modulation of the biosynthesis of cell wall associated lipids and triacylglycerol (TAG). An accumulation of TAG-containing lipid bodies is further confirmed by using 14C oleate incorporation. Interestingly, the mutant also shows an overexpression of TAG-degrading lipase genes, and the intracellular lipolytic enzymes mediate TAG hydrolysis for their utilization as energy source. We believe that our in vitro energy-depleted model will allow us to explore the critical link between energy metabolism, redox homeostasis, and lipid biosynthesis during ATP-depleted state, which will enhance our understanding of the bacterial adaptation, and will allow us to identify novel drug targets to counter mycobacterial infections.
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Affiliation(s)
- Varsha Patil
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
| | - Vikas Jain
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, India
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17
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Cryo-EM structure of mycobacterial cytochrome bd reveals two oxygen access channels. Nat Commun 2021; 12:4621. [PMID: 34330928 PMCID: PMC8324918 DOI: 10.1038/s41467-021-24924-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 07/14/2021] [Indexed: 12/21/2022] Open
Abstract
Cytochromes bd are ubiquitous amongst prokaryotes including many human-pathogenic bacteria. Such complexes are targets for the development of antimicrobial drugs. However, an understanding of the relationship between the structure and functional mechanisms of these oxidases is incomplete. Here, we have determined the 2.8 Å structure of Mycobacterium smegmatis cytochrome bd by single-particle cryo-electron microscopy. This bd oxidase consists of two subunits CydA and CydB, that adopt a pseudo two-fold symmetrical arrangement. The structural topology of its Q-loop domain, whose function is to bind the substrate, quinol, is significantly different compared to the C-terminal region reported for cytochromes bd from Geobacillus thermodenitrificans (G. th) and Escherichia coli (E. coli). In addition, we have identified two potential oxygen access channels in the structure and shown that similar tunnels also exist in G. th and E. coli cytochromes bd. This study provides insights to develop a framework for the rational design of antituberculosis compounds that block the oxygen access channels of this oxidase. Cytochromes bd oxidase (Cyt-bd) catalyzes the reduction of oxygen to water and is the terminal oxidase in the respiratory chain of prokaryotes. Here, the authors present the 2.8 Å cryo-EM structure of Mycobacterium smegmatis Cyt-bd and identify two potential oxygen access channels in the structure, which is of interest for the development of novel antituberculosis drugs.
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18
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Cai Y, Jaecklein E, Mackenzie JS, Papavinasasundaram K, Olive AJ, Chen X, Steyn AJC, Sassetti CM. Host immunity increases Mycobacterium tuberculosis reliance on cytochrome bd oxidase. PLoS Pathog 2021; 17:e1008911. [PMID: 34320028 PMCID: PMC8351954 DOI: 10.1371/journal.ppat.1008911] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 08/09/2021] [Accepted: 07/12/2021] [Indexed: 11/18/2022] Open
Abstract
In order to sustain a persistent infection, Mycobacterium tuberculosis (Mtb) must adapt to a changing environment that is shaped by the developing immune response. This necessity to adapt is evident in the flexibility of many aspects of Mtb metabolism, including a respiratory chain that consists of two distinct terminal cytochrome oxidase complexes. Under the conditions tested thus far, the bc1/aa3 complex appears to play a dominant role, while the alternative bd oxidase is largely redundant. However, the presence of two terminal oxidases in this obligate pathogen implies that respiratory requirements might change during infection. We report that the cytochrome bd oxidase is specifically required for resisting the adaptive immune response. While the bd oxidase was dispensable for growth in resting macrophages and the establishment of infection in mice, this complex was necessary for optimal fitness after the initiation of adaptive immunity. This requirement was dependent on lymphocyte-derived interferon gamma (IFNγ), but did not involve nitrogen and oxygen radicals that are known to inhibit respiration in other contexts. Instead, we found that ΔcydA mutants were hypersusceptible to the low pH encountered in IFNγ-activated macrophages. Unlike wild type Mtb, cytochrome bd-deficient bacteria were unable to sustain a maximal oxygen consumption rate (OCR) at low pH, indicating that the remaining cytochrome bc1/aa3 complex is preferentially inhibited under acidic conditions. Consistent with this model, the potency of the cytochrome bc1/aa3 inhibitor, Q203, is dramatically enhanced at low pH. This work identifies a critical interaction between host immunity and pathogen respiration that influences both the progression of the infection and the efficacy of potential new TB drugs.
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Affiliation(s)
- Yi Cai
- Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Department of Pathogen Biology, Shenzhen University School of Medicine, Shenzhen, China
| | - Eleni Jaecklein
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | | | - Kadamba Papavinasasundaram
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Andrew J Olive
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Xinchun Chen
- Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Department of Pathogen Biology, Shenzhen University School of Medicine, Shenzhen, China
| | | | - Christopher M Sassetti
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
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19
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Borisov VB, Siletsky SA, Paiardini A, Hoogewijs D, Forte E, Giuffrè A, Poole RK. Bacterial Oxidases of the Cytochrome bd Family: Redox Enzymes of Unique Structure, Function, and Utility As Drug Targets. Antioxid Redox Signal 2021; 34:1280-1318. [PMID: 32924537 PMCID: PMC8112716 DOI: 10.1089/ars.2020.8039] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/23/2022]
Abstract
Significance: Cytochrome bd is a ubiquinol:oxygen oxidoreductase of many prokaryotic respiratory chains with a unique structure and functional characteristics. Its primary role is to couple the reduction of molecular oxygen, even at submicromolar concentrations, to water with the generation of a proton motive force used for adenosine triphosphate production. Cytochrome bd is found in many bacterial pathogens and, surprisingly, in bacteria formally denoted as anaerobes. It endows bacteria with resistance to various stressors and is a potential drug target. Recent Advances: We summarize recent advances in the biochemistry, structure, and physiological functions of cytochrome bd in the light of exciting new three-dimensional structures of the oxidase. The newly discovered roles of cytochrome bd in contributing to bacterial protection against hydrogen peroxide, nitric oxide, peroxynitrite, and hydrogen sulfide are assessed. Critical Issues: Fundamental questions remain regarding the precise delineation of electron flow within this multihaem oxidase and how the extraordinarily high affinity for oxygen is accomplished, while endowing bacteria with resistance to other small ligands. Future Directions: It is clear that cytochrome bd is unique in its ability to confer resistance to toxic small molecules, a property that is significant for understanding the propensity of pathogens to possess this oxidase. Since cytochrome bd is a uniquely bacterial enzyme, future research should focus on harnessing fundamental knowledge of its structure and function to the development of novel and effective antibacterial agents.
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Affiliation(s)
- Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Sergey A. Siletsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | | | - David Hoogewijs
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Elena Forte
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | | | - Robert K. Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
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20
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Gautam K, Negi S, Saini V. Targeting endogenous gaseous signaling molecules as novel host-directed therapies against tuberculosis infection. Free Radic Res 2021; 55:655-670. [PMID: 33641567 DOI: 10.1080/10715762.2021.1892091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Tuberculosis (TB) is a chronic pulmonary disease caused by Mycobacterium tuberculosis which is a major cause of morbidity and mortality worldwide. Due to the complexity of disease and its continuous global spread, there is an urgent need to improvise the strategies for prevention, diagnosis, and treatment. The current anti-TB regimen lasts for months and warrants strict compliance to clear infection and to minimize the risk of development of multi drug-resistant tuberculosis. This underscores the need to have new and improved therapeutics for TB treatment. Several studies have highlighted the unique ability of Mycobacterium tuberculosis to exploit host factors to support its survival inside the intracellular environment. One of the key players to mycobacterial disease susceptibility and infection are endogenous gases such as oxygen, nitric oxide, carbon monoxide and hydrogen sulfide. Nitric oxide and carbon monoxide as the physiological gaseous messengers are considered important to the outcome of Mycobacterium tuberculosis infection. The role of hydrogen sulfide in human tuberculosis is yet not fully elucidated, but this gas has been shown to play a significant role in bacterial respiration, growth and pathogenesis. This review will focus on the host factors majorly endogenous gaseous signaling molecules which contributes to Mycobacterium tuberculosis survival inside the intracellular environment and highlight the potential therapeutic targets.
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Affiliation(s)
- Kamini Gautam
- Laboratory of Infection Biology and Translational Research, Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Sheetal Negi
- Laboratory of Infection Biology and Translational Research, Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Vikram Saini
- Laboratory of Infection Biology and Translational Research, Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi, India
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21
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Lee BS, Hards K, Engelhart CA, Hasenoehrl EJ, Kalia NP, Mackenzie JS, Sviriaeva E, Chong SMS, Manimekalai MSS, Koh VH, Chan J, Xu J, Alonso S, Miller MJ, Steyn AJC, Grüber G, Schnappinger D, Berney M, Cook GM, Moraski GC, Pethe K. Dual inhibition of the terminal oxidases eradicates antibiotic-tolerant Mycobacterium tuberculosis. EMBO Mol Med 2021; 13:e13207. [PMID: 33283973 PMCID: PMC7799364 DOI: 10.15252/emmm.202013207] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 11/09/2022] Open
Abstract
The approval of bedaquiline has placed energy metabolism in the limelight as an attractive target space for tuberculosis antibiotic development. While bedaquiline inhibits the mycobacterial F1 F0 ATP synthase, small molecules targeting other components of the oxidative phosphorylation pathway have been identified. Of particular interest is Telacebec (Q203), a phase 2 drug candidate inhibitor of the cytochrome bcc:aa3 terminal oxidase. A functional redundancy between the cytochrome bcc:aa3 and the cytochrome bd oxidase protects M. tuberculosis from Q203-induced death, highlighting the attractiveness of the bd-type terminal oxidase for drug development. Here, we employed a facile whole-cell screen approach to identify the cytochrome bd inhibitor ND-011992. Although ND-011992 is ineffective on its own, it inhibits respiration and ATP homeostasis in combination with Q203. The drug combination was bactericidal against replicating and antibiotic-tolerant, non-replicating mycobacteria, and increased efficacy relative to that of a single drug in a mouse model. These findings suggest that a cytochrome bd oxidase inhibitor will add value to a drug combination targeting oxidative phosphorylation for tuberculosis treatment.
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Affiliation(s)
- Bei Shi Lee
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
| | - Kiel Hards
- Department of Microbiology and ImmunologySchool of Biomedical SciencesUniversity of OtagoDunedinNew Zealand
- Maurice Wilkins Centre for Molecular BiodiscoveryUniversity of AucklandAucklandNew Zealand
| | - Curtis A Engelhart
- Department of Microbiology and ImmunologyWeill Cornell Medical CollegeNew YorkNYUSA
| | - Erik J Hasenoehrl
- Department of Microbiology and ImmunologyAlbert Einstein College of MedicineBronxNYUSA
| | - Nitin P Kalia
- Lee Kong Chian School of MedicineNanyang Technological UniversitySingaporeSingapore
- Ramalingaswami FellowClinical Microbiology DivisionCSIR‐IIIMJammu and KashmirIndia
| | - Jared S Mackenzie
- Africa Health Research InstituteNelson R. Mandela School of MedicineUniversity of KwaZulu‐NatalDurbanSouth Africa
| | - Ekaterina Sviriaeva
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
| | - Shi Min Sherilyn Chong
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
- Nanyang Institute of Technology in Health and MedicineInterdisciplinary Graduate SchoolNanyang Technological UniversitySingaporeSingapore
| | | | - Vanessa H Koh
- Department of MicrobiologyYong Loo Lin School of MedicineNational University of SingaporeSingaporeSingapore
- Infectious Disease ProgrammeDepartment of Microbiology and ImmunologyNational University of SingaporeSingaporeSingapore
| | - John Chan
- Department of MedicineAlbert Einstein College of MedicineBronxNYUSA
| | - Jiayong Xu
- Department of MedicineAlbert Einstein College of MedicineBronxNYUSA
| | - Sylvie Alonso
- Department of MicrobiologyYong Loo Lin School of MedicineNational University of SingaporeSingaporeSingapore
- Infectious Disease ProgrammeDepartment of Microbiology and ImmunologyNational University of SingaporeSingaporeSingapore
| | - Marvin J Miller
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameINUSA
| | - Adrie J C Steyn
- Africa Health Research InstituteNelson R. Mandela School of MedicineUniversity of KwaZulu‐NatalDurbanSouth Africa
- Department of MicrobiologyUniversity of AlabamaBirminghamALUSA
| | - Gerhard Grüber
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
| | - Dirk Schnappinger
- Department of Microbiology and ImmunologyWeill Cornell Medical CollegeNew YorkNYUSA
| | - Michael Berney
- Department of Microbiology and ImmunologyAlbert Einstein College of MedicineBronxNYUSA
| | - Gregory M Cook
- Department of Microbiology and ImmunologySchool of Biomedical SciencesUniversity of OtagoDunedinNew Zealand
- Maurice Wilkins Centre for Molecular BiodiscoveryUniversity of AucklandAucklandNew Zealand
| | - Garrett C Moraski
- Department of Chemistry and BiochemistryMontana State UniversityBozemanMTUSA
| | - Kevin Pethe
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
- Lee Kong Chian School of MedicineNanyang Technological UniversitySingaporeSingapore
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22
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Hasenoehrl EJ, Wiggins TJ, Berney M. Bioenergetic Inhibitors: Antibiotic Efficacy and Mechanisms of Action in Mycobacterium tuberculosis. Front Cell Infect Microbiol 2021; 10:611683. [PMID: 33505923 PMCID: PMC7831573 DOI: 10.3389/fcimb.2020.611683] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/23/2020] [Indexed: 11/23/2022] Open
Abstract
Development of novel anti-tuberculosis combination regimens that increase efficacy and reduce treatment timelines will improve patient compliance, limit side-effects, reduce costs, and enhance cure rates. Such advancements would significantly improve the global TB burden and reduce drug resistance acquisition. Bioenergetics has received considerable attention in recent years as a fertile area for anti-tuberculosis drug discovery. Targeting the electron transport chain (ETC) and oxidative phosphorylation machinery promises not only to kill growing cells but also metabolically dormant bacilli that are inherently more drug tolerant. Over the last two decades, a broad array of drugs targeting various ETC components have been developed. Here, we provide a focused review of the current state of art of bioenergetic inhibitors of Mtb with an in-depth analysis of the metabolic and bioenergetic disruptions caused by specific target inhibition as well as their synergistic and antagonistic interactions with other drugs. This foundation is then used to explore the reigning theories on the mechanisms of antibiotic-induced cell death and we discuss how bioenergetic inhibitors in particular fail to be adequately described by these models. These discussions lead us to develop a clear roadmap for new lines of investigation to better understand the mechanisms of action of these drugs with complex mechanisms as well as how to leverage that knowledge for the development of novel, rationally-designed combination therapies to cure TB.
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Affiliation(s)
- Erik J Hasenoehrl
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Thomas J Wiggins
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
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23
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Small organic molecules targeting the energy metabolism of Mycobacterium tuberculosis. Eur J Med Chem 2020; 212:113139. [PMID: 33422979 DOI: 10.1016/j.ejmech.2020.113139] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 11/21/2022]
Abstract
Causing approximately 10 million incident cases and 1.3-1.5 million deaths every year, Mycobacterium tuberculosis remains a global health problem. The risk is further exacerbated with latent tuberculosis (TB) infection, the HIV pandemic, and increasing anti-TB drug resistance. Therefore, unexplored chemical scaffolds directed towards new molecular targets are increasingly desired. In this context, mycobacterial energy metabolism, particularly the oxidative phosphorylation (OP) pathway, is gaining importance. Mycobacteria possess primary dehydrogenases to fuel electron transport; aa3-type cytochrome c oxidase and bd-type menaquinol oxidase to generate a protonmotive force; and ATP synthase, which is essential for both growing mycobacteria as well as dormant mycobacteria because ATP is produced under both aerobic and hypoxic conditions. Small organic molecules targeting OP are active against latent TB as well as resistant TB strains. FDA approval of the ATP synthase inhibitor bedaquiline and the discovery of clinical candidate Q203, which both interfere with the cytochrome bc1 complex, have already confirmed mycobacterial energy metabolism to be a valuable anti-TB drug target. This review highlights both preferable molecular targets within mycobacterial OP and promising small organic molecules targeting OP. Progressive research in the area of mycobacterial OP revealed several highly potent anti-TB compounds with nanomolar-range MICs as low as 0.004 μM against Mtb H37Rv. Therefore, we are convinced that targeting the OP pathway can combat resistant TB and latent TB, leading to more efficient anti-TB chemotherapy.
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24
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Ko EM, Oh JI. Induction of the cydAB Operon Encoding the bd Quinol Oxidase Under Respiration-Inhibitory Conditions by the Major cAMP Receptor Protein MSMEG_6189 in Mycobacterium smegmatis. Front Microbiol 2020; 11:608624. [PMID: 33343552 PMCID: PMC7739888 DOI: 10.3389/fmicb.2020.608624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/06/2020] [Indexed: 12/29/2022] Open
Abstract
The respiratory electron transport chain (ETC) of Mycobacterium smegmatis is terminated with two terminal oxidases, the aa 3 cytochrome c oxidase and the cytochrome bd quinol oxidase. The bd quinol oxidase with a higher binding affinity for O2 than the aa 3 oxidase is known to play an important role in aerobic respiration under oxygen-limiting conditions. Using relevant crp1 (MSMEG_6189) and crp2 (MSMEG_0539) mutant strains of M. smegmatis, we demonstrated that Crp1 plays a predominant role in induction of the cydAB operon under ETC-inhibitory conditions. Two Crp-binding sequences were identified upstream of the cydA gene, both of which are necessary for induction of cydAB expression under ETC-inhibitory conditions. The intracellular level of cAMP in M. smegmatis was found to be increased under ETC-inhibitory conditions. The crp2 gene was found to be negatively regulated by Crp1 and Crp2, which appears to lead to significantly low cellular abundance of Crp2 relative to Crp1 in M. smegmatis. Our RNA sequencing analyses suggest that in addition to the SigF partner switching system, Crp1 is involved in induction of gene expression in M. smegmatis exposed to ETC-inhibitory conditions.
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Affiliation(s)
- Eon-Min Ko
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Jeong-Il Oh
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
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The ATP-Binding Cassette (ABC) Transport Systems in Mycobacterium tuberculosis: Structure, Function, and Possible Targets for Therapeutics. BIOLOGY 2020; 9:biology9120443. [PMID: 33291531 PMCID: PMC7761784 DOI: 10.3390/biology9120443] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 11/06/2020] [Accepted: 11/12/2020] [Indexed: 12/22/2022]
Abstract
Simple Summary Mycobacterium tuberculosis is a bacterium of great medical importance because it causes tuberculosis, a disease that affects millions of people worldwide. Two important features are related to this bacterium: its ability to infect and survive inside the host, minimizing the immune response, and the burden of clinical isolates that are highly resistant to antibiotics treatment. These two phenomena are directly affected by cell envelope proteins, such as proteins from the ATP-Binding Cassette (ABC transporters) superfamily. In this review, we have compiled information on all the M. tuberculosis ABC transporters described so far, both from a functional and structural point of view, and show their relevance for the bacillus and the potential targets for studies aiming to control the microorganism and structural features. Abstract Mycobacterium tuberculosis is the etiological agent of tuberculosis (TB), a disease that affects millions of people in the world and that is associated with several human diseases. The bacillus is highly adapted to infect and survive inside the host, mainly because of its cellular envelope plasticity, which can be modulated to adapt to an unfriendly host environment; to manipulate the host immune response; and to resist therapeutic treatment, increasing in this way the drug resistance of TB. The superfamily of ATP-Binding Cassette (ABC) transporters are integral membrane proteins that include both importers and exporters. Both types share a similar structural organization, yet only importers have a periplasmic substrate-binding domain, which is essential for substrate uptake and transport. ABC transporter-type importers play an important role in the bacillus physiology through the transport of several substrates that will interfere with nutrition, pathogenesis, and virulence. Equally relevant, exporters have been involved in cell detoxification, nutrient recycling, and antibiotics and drug efflux, largely affecting the survival and development of multiple drug-resistant strains. Here, we review known ABC transporters from M. tuberculosis, with particular focus on the diversity of their structural features and relevance in infection and drug resistance.
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Bajeli S, Baid N, Kaur M, Pawar GP, Chaudhari VD, Kumar A. Terminal Respiratory Oxidases: A Targetables Vulnerability of Mycobacterial Bioenergetics? Front Cell Infect Microbiol 2020; 10:589318. [PMID: 33330134 PMCID: PMC7719681 DOI: 10.3389/fcimb.2020.589318] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022] Open
Abstract
Recently, ATP synthase inhibitor Bedaquiline was approved for the treatment of multi-drug resistant tuberculosis emphasizing the importance of oxidative phosphorylation for the survival of mycobacteria. ATP synthesis is primarily dependent on the generation of proton motive force through the electron transport chain in mycobacteria. The mycobacterial electron transport chain utilizes two terminal oxidases for the reduction of oxygen, namely the bc1-aa3 supercomplex and the cytochrome bd oxidase. The bc1-aa3 supercomplex is an energy-efficient terminal oxidase that pumps out four vectoral protons, besides consuming four scalar protons during the transfer of electrons from menaquinone to molecular oxygen. In the past few years, several inhibitors of bc1-aa3 supercomplex have been developed, out of which, Q203 belonging to the class of imidazopyridine, has moved to clinical trials. Recently, the crystal structure of the mycobacterial cytochrome bc1-aa3 supercomplex was solved, providing details of the route of transfer of electrons from menaquinone to molecular oxygen. Besides providing insights into the molecular functioning, crystal structure is aiding in the targeted drug development. On the other hand, the second respiratory terminal oxidase of the mycobacterial respiratory chain, cytochrome bd oxidase, does not pump out the vectoral protons and is energetically less efficient. However, it can detoxify the reactive oxygen species and facilitate mycobacterial survival during a multitude of stresses. Quinolone derivatives (CK-2-63) and quinone derivative (Aurachin D) inhibit cytochrome bd oxidase. Notably, ablation of both the two terminal oxidases simultaneously through genetic methods or pharmacological inhibition leads to the rapid death of the mycobacterial cells. Thus, terminal oxidases have emerged as important drug targets. In this review, we have described the current understanding of the functioning of these two oxidases, their physiological relevance to mycobacteria, and their inhibitors. Besides these, we also describe the alternative terminal complexes that are used by mycobacteria to maintain energized membrane during hypoxia and anaerobic conditions.
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Affiliation(s)
- Sapna Bajeli
- Molecular Mycobacteriology, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Navin Baid
- Molecular Mycobacteriology, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Manjot Kaur
- Division of Medicinal Chemistry, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Ganesh P Pawar
- Division of Medicinal Chemistry, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Vinod D Chaudhari
- Division of Medicinal Chemistry, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Ashwani Kumar
- Molecular Mycobacteriology, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
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Hamidieh F, Farnia P, Nowroozi J, Farnia P, Velayati AA. An Overview of Genetic Information of Latent Mycobacterium tuberculosis. Tuberc Respir Dis (Seoul) 2020; 84:1-12. [PMID: 33121230 PMCID: PMC7801807 DOI: 10.4046/trd.2020.0116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 10/30/2020] [Indexed: 11/24/2022] Open
Abstract
Mycobacterium tuberculosis has infected more than two billion individuals worldwide, of whom 5%–10% have clinically active disease and 90%–95% remain in the latent stage with a reservoir of viable bacteria in the macrophages for extended periods of time. The tubercle bacilli at this stage are usually called dormant, non-viable, and/or non-culturable microorganisms. The patients with latent bacilli will not have clinical pictures and are not infectious. The infections in about 2%–23% of the patients with latent status become reactivated for various reasons such as cancer, human immunodeficiency virus infection, diabetes, and/or aging. Many studies have examined the mechanisms involved in the latent state of Mycobacterium and showed that latency modified the expression of many genes. Therefore, several mechanisms will change in this bacterium. Hence, this study aimed to briefly examine the genes involved in the latent state as well as the changes that are caused by Mycobacterium tuberculosis. The study also evaluated the relationship between the functions of these genes.
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Affiliation(s)
- Faezeh Hamidieh
- Departement of Microbiology, Faculty of Biological Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Parissa Farnia
- Mycobacteriology Research (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Jamileh Nowroozi
- Departement of Microbiology, Faculty of Biological Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Poopak Farnia
- Mycobacteriology Research (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Biotechnology, School of Advanced Technology in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Akbar Velayati
- Mycobacteriology Research (MRC), National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Bespyatykh J, Bespiatykh D, Malakhova M, Klimina K, Bespyatykh A, Varizhuk A, Tevyashova A, Nikolenko T, Pozmogova G, Ilina E, Shitikov E. Aureolic Acid Group of Agents as Potential Antituberculosis Drugs. Antibiotics (Basel) 2020; 9:E715. [PMID: 33086595 PMCID: PMC7650759 DOI: 10.3390/antibiotics9100715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 11/16/2022] Open
Abstract
Mycobacterium tuberculosis is one of the most dangerous pathogens. Bacterial resistance to antituberculosis drugs grows each year, but searching for new drugs is a long process. Testing for available drugs to find active against mycobacteria may be a good alternative. In this work, antibiotics of the aureolic acid group were tested on a model organism Mycobacterium smegmatis. We presumed that antibiotics of this group may be potential G4 ligands. However, this was not confirmed in our analyses. We determined the antimicrobial activity of these drugs and revealed morphological changes in the cell structure upon treatment. Transcriptomic analysis documented increased expression of MSMEG_3743/soj and MSMEG_4228/ftsW, involved in cell division. Therefore, drugs may affect cell division, possibly disrupting the function of the Z-ring and the formation of a septum. Additionally, a decrease in the transcription level of several indispensable genes, such as nitrate reductase subunits (MSMEG_5137/narI and MSMEG_5139/narX) and MSMEG_3205/hisD was shown. We concluded that the mechanism of action of aureolic acid and its related compounds may be similar to that bedaquiline and disturb the NAD+/NADH balance in the cell. All of this allowed us to conclude that aureolic acid derivatives can be considered as potential antituberculosis drugs.
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Affiliation(s)
- Julia Bespyatykh
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
| | - Dmitry Bespiatykh
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
| | - Maja Malakhova
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
| | - Ksenia Klimina
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
| | - Andrey Bespyatykh
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia;
| | - Anna Varizhuk
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
| | | | - Tatiana Nikolenko
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia
| | - Galina Pozmogova
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
| | - Elena Ilina
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
| | - Egor Shitikov
- Federal Research and Clinical Centre of Physical-Chemical Medicine, 119435 Moscow, Russia; (D.B.); (M.M.); (K.K.); (A.V.); (T.N.); (G.P.); (E.I.); (E.S.)
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Patil S, Palande A, Lodhiya T, Pandit A, Mukherjee R. Redefining genetic essentiality in Mycobacterium tuberculosis. Gene 2020; 765:145091. [PMID: 32898604 DOI: 10.1016/j.gene.2020.145091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 08/18/2020] [Accepted: 08/21/2020] [Indexed: 11/15/2022]
Abstract
Sequencing transposon mutant libraries have been pivotal in annotating essential and non-essential genes in bacteria. This is particularly very helpful in the case of Mycobacterium tuberculosis with a large part of its genome without known function. It is not known whether there are any variations in the essentiality states as a function of optimal growth in the absence of any selection pressure. We here grow a high-density mutant library of M. tuberculosis through serial cultures and monitor the temporal fluctuations in insertion frequencies across all TA dinucleotides in the genome. Genes that cause morphological and physiological heterogeneity or enable metabolic bypass were found to gradually lose insertions, while genes comprising the toxin-antitoxin systems were found to get enriched with insertions during growth in nutrient replete conditions. High levels of fluctuations were observed in genes involved in cell wall and cell processes, intermediary metabolism, and genes involved in virulence, suggesting new modes of adaptation undertaken by the mutants. We also report the essentiality status of several newly annotated genetic features.
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Affiliation(s)
- Saniya Patil
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, India
| | - Aseem Palande
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, India
| | - Tejan Lodhiya
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, India
| | - Awadhesh Pandit
- National Center for Biological Sciences, Bengaluru 560065, India
| | - Raju Mukherjee
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, India.
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Sviriaeva E, Subramanian Manimekalai MS, Grüber G, Pethe K. Features and Functional Importance of Key Residues of the Mycobacterium tuberculosis Cytochrome bd Oxidase. ACS Infect Dis 2020; 6:1697-1707. [PMID: 32379966 DOI: 10.1021/acsinfecdis.9b00449] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome bd (cyt-bd) oxygen reductases have a high affinity to oxygen and use the two electrons provided by ubiquinol or menaquinol, like in mycobacteria, to reduce oxygen to water. Although they do not pump protons from the cytoplasmic to the periplasmic side, they generate a proton motive force due to the release of protons after quinol oxidation. Here, we show that the mycobacterial cyt-bd has a number of specific features, including a 17-residue stretch (307SGVTLQGIRDLQQEYQQ323) near the Q-loop of the Mycobacterium tuberculosis subunit CydA and a 412QLVRLTVKA420 region on the periplasmic side. Site directed mutagenesis and whole-bacteria assays demonstrated that these mycobacteria-specific stretches are essential for the oxidase's function. Single amino acid substitutions around the 307SGVTLQGIRDLQQEYQQ323 stretch revealed the importance of the aromatic residue Y330 in oxygen consumption and consequently in ATP synthesis. A moderate reduction and no effect was observed for mutants F325 and Y321, respectively, while the double mutant CydAY321/F325 drastically reduced enzyme activity. In addition, single mutants of the mycobacterial cyt-bd were generated to probe the role of proposed critical residues for proton shuffling. Further data demonstrate that amino acids W64 and F18 in the CydB subunit might be important as any slight destabilization of the hydrophobic environment near them makes the enzyme inactive. Finally, the potential of the mycobacterial cyt-bd as a drug target is discussed.
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Affiliation(s)
- Ekaterina Sviriaeva
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
- Lee Kong Chian School of Medicine, 59 Nanyang Drive, Singapore 636921, Republic of Singapore
| | | | - Gerhard Grüber
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
| | - Kevin Pethe
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
- Lee Kong Chian School of Medicine, 59 Nanyang Drive, Singapore 636921, Republic of Singapore
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Chong SMS, Manimekalai MSS, Sarathy JP, Williams ZC, Harold LK, Cook GM, Dick T, Pethe K, Bates RW, Grüber G. Antituberculosis Activity of the Antimalaria Cytochrome bcc Oxidase Inhibitor SCR0911. ACS Infect Dis 2020; 6:725-737. [PMID: 32092260 DOI: 10.1021/acsinfecdis.9b00408] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ability to respire and generate adenosine triphosphate (ATP) is essential for the physiology, persistence, and pathogenicity of Mycobacterium tuberculosis, which causes tuberculosis. By employing a lead repurposing strategy, the malarial cytochrome bc1 inhibitor SCR0911 was tested against mycobacteria. Docking studies were carried out to reveal potential binding and to understand the binding interactions with the target, cytochrome bcc. Whole-cell-based and in vitro assays demonstrated the potency of SCR0911 by inhibiting cell growth and ATP synthesis in both the fast- and slow-growing M. smegmatis and M. bovis bacillus Calmette-Guérin, respectively. The variety of biochemical assays and the use of a cytochrome bcc deficient mutant strain validated the cytochrome bcc oxidase as the direct target of the drug. The data demonstrate the broad-spectrum activity of SCR0911 and open the door for structure-activity relationship studies to improve the potency of new mycobacteria specific SCR0911 analogues.
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Affiliation(s)
- Shi Min Sherilyn Chong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Republic of Singapore
- Nanyang Institute of Technology in Health and Medicine, Interdisciplinary Graduate School, Nanyang Technological University, Singapore 637551, Republic of Singapore
| | | | - Jickky Palmae Sarathy
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599, Republic of Singapore
| | - Zoe C. Williams
- 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
| | - Gregory M. Cook
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Thomas Dick
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599, Republic of Singapore
- Center for Discovery and Innovation, Hackensack Meridian Health, 340 Kingsland Street Building 102, Nutley, New Jersey 07110, United States
| | - Kevin Pethe
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore
| | - Roderick W. Bates
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Republic of Singapore
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
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Lee BS, Sviriaeva E, Pethe K. Targeting the cytochrome oxidases for drug development in mycobacteria. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 152:45-54. [PMID: 32081616 DOI: 10.1016/j.pbiomolbio.2020.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 01/15/2020] [Accepted: 02/06/2020] [Indexed: 11/19/2022]
Abstract
Mycobacterium tuberculosis strictly depends on oxygen to multiply, and the terminal oxidases are a vital part of the oxidative phosphorylation pathway. The bacterium possesses two aerobic respiratory branches: a cytochrome bcc-aa3 and a bacteria-specific cytochrome bd oxidase. The identification of small-molecule inhibitors of the cytochrome bcc-aa3 under numerous experimental conditions reflects the essentiality of the pathway for the optimum growth of M. tuberculosis. Recent findings on the biology of the cytochrome bcc-aa3 as well as the report of the first high-resolution structure of a mycobacterial cytochrome bcc-aa3 complex will help in the characterization and further development of potent inhibitors. Although the aerobic cytochrome bd respiratory branch is not strictly essential for growth, the discovery of a strong synthetic lethal interaction with the cytochrome bcc-aa3 placed the cytochrome bd oxidase under the spotlight as an attractive drug target for its synergistic role in potentiating the efficacy of cytochrome bcc-aa3 inhibitors and other drugs targeting oxidative phosphorylation. In this review, we are discussing current knowledge about the two mycobacterial aerobic respiratory branches, their potential as drug targets, as well as potential drawbacks.
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Affiliation(s)
- Bei Shi Lee
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Ekaterina Sviriaeva
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Kevin Pethe
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, 636921, Singapore.
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Goojani HG, Konings J, Hakvoort H, Hong S, Gennis RB, Sakamoto J, Lill H, Bald D. The carboxy-terminal insert in the Q-loop is needed for functionality of Escherichia coli cytochrome bd-I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148175. [PMID: 32061652 DOI: 10.1016/j.bbabio.2020.148175] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 01/24/2020] [Accepted: 02/10/2020] [Indexed: 12/27/2022]
Abstract
Cytochrome bd, a component of the prokaryotic respiratory chain, is important under physiological stress and during pathogenicity. Electrons from quinol substrates are passed on via heme groups in the CydA subunit and used to reduce molecular oxygen. Close to the quinol binding site, CydA displays a periplasmic hydrophilic loop called Q-loop that is essential for quinol oxidation. In the carboxy-terminal part of this loop, CydA from Escherichia coli and other proteobacteria harbors an insert of ~60 residues with unknown function. In the current work, we demonstrate that growth of the multiple-deletion strain E. coli MB43∆cydA (∆cydA∆cydB∆appB∆cyoB∆nuoB) can be enhanced by transformation with E. coli cytochrome bd-I and we utilize this system for assessment of Q-loop mutants. Deletion of the cytochrome bd-I Q-loop insert abolished MB43∆cydA growth recovery. Swapping the cytochrome bd-I Q-loop for the Q-loop from Geobacillus thermodenitrificans or Mycobacterium tuberculosis CydA, which lack the insert, did not enhance the growth of MB43∆cydA, whereas swapping for the Q-loop from E. coli cytochrome bd-II recovered growth. Alanine scanning experiments identified the cytochrome bd-I Q-loop insert regions Ile318-Met322, Gln338-Asp342, Tyr353-Leu357, and Thr368-Ile372 as important for enzyme functionality. Those mutants that completely failed to recover growth of MB43∆cydA also lacked oxygen consumption activity and heme absorption peaks. Moreover, we were not able to isolate cytochrome bd-I from these inactive mutants. The results indicate that the cytochrome bd Q-loop exhibits low plasticity and that the Q-loop insert in E. coli is needed for complete, stable, assembly of cytochrome bd-I.
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Affiliation(s)
- Hojjat Ghasemi Goojani
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Julia Konings
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Henk Hakvoort
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Sangjin Hong
- Department of Biochemistry, University of Illinois, 600 S. Mathews Avenue, Urbana, IL 61801, United States
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, 600 S. Mathews Avenue, Urbana, IL 61801, United States
| | - Junshi Sakamoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka-ken 820-8502, Japan
| | - Holger Lill
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands.
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Trutneva KA, Shleeva MO, Demina GR, Vostroknutova GN, Kaprelyans AS. One-Year Old Dormant, "Non-culturable" Mycobacterium tuberculosis Preserves Significantly Diverse Protein Profile. Front Cell Infect Microbiol 2020; 10:26. [PMID: 32117801 PMCID: PMC7025520 DOI: 10.3389/fcimb.2020.00026] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/15/2020] [Indexed: 12/15/2022] Open
Abstract
For adaptation to stressful conditions, Mycobacterium tuberculosis (Mtb) is prone to transit to a dormant, non-replicative state, which is believed to be the basis of the latent form of tuberculosis infection. Dormant bacteria persist in the host for a long period without multiplication, cannot be detected from biological samples by microbiological methods, however, their "non-culturable" state is reversible. Mechanisms supporting very long capacity of mycobacteria for resuscitation and further multiplication after prolonged survival in a dormant phase remain unclear. Using methods of 2D electrophoresis and MALDI-TOF analysis, in this study we characterized changes in the proteomic profile of Mtb stored for more than a year as dormant, non-replicating cells with a negligible metabolic activity, full resistance to antibiotics, and altered morphology (ovoid forms). Despite some protein degradation, the proteome of 1-year-old dormant mycobacteria retained numerous intact proteins. Their protein profile differed profoundly from that of metabolically active cells, but was similar to the proteome of the 4-month-old dormant bacteria. Such protein stability is likely to be due to the presence of a significant number of enzymes involved in the protection from oxidative stress (katG/Rv1908, sodA/Rv3846, sodC/Rv0432, bpoC/Rv0554), as well as chaperones (dnaJ1/Rv0352, htpG/Rv2299, groEL2/Rv0440, dnaK/Rv0350, groES/Rv3418, groEL1/Rv3417, HtpG/Rv2299c, hspX/Rv2031), and DNA-stabilizing proteins. In addition, dormant cells proteome contains enzymes involved in specific metabolic pathways (glycolytic reactions, shortened TCA cycle, degradative processes) potentially providing a low-level metabolism, or these proteins could be "frozen" for usage in the reactivation process before biosynthetic processes start. The observed stability of proteins in a dormant state could be a basis for the long-term preservation of Mtb cell vitality and hence for latent tuberculosis.
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Affiliation(s)
- Kseniya A Trutneva
- Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, Moscow, Russia
| | - Margarita O Shleeva
- Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, Moscow, Russia
| | - Galina R Demina
- Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, Moscow, Russia
| | - Galina N Vostroknutova
- Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, Moscow, Russia
| | - Arseny S Kaprelyans
- Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, A.N. Bach Institute of Biochemistry, Moscow, Russia
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Saini V, Chinta KC, Reddy VP, Glasgow JN, Stein A, Lamprecht DA, Rahman MA, Mackenzie JS, Truebody BE, Adamson JH, Kunota TTR, Bailey SM, Moellering DR, Lancaster JR, Steyn AJC. Hydrogen sulfide stimulates Mycobacterium tuberculosis respiration, growth and pathogenesis. Nat Commun 2020; 11:557. [PMID: 31992699 PMCID: PMC6987094 DOI: 10.1038/s41467-019-14132-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 12/13/2019] [Indexed: 01/23/2023] Open
Abstract
Hydrogen sulfide (H2S) is involved in numerous pathophysiological processes and shares overlapping functions with CO and •NO. However, the importance of host-derived H2S in microbial pathogenesis is unknown. Here we show that Mtb-infected mice deficient in the H2S-producing enzyme cystathionine β-synthase (CBS) survive longer with reduced organ burden, and that pharmacological inhibition of CBS reduces Mtb bacillary load in mice. High-resolution respirometry, transcriptomics and mass spectrometry establish that H2S stimulates Mtb respiration and bioenergetics predominantly via cytochrome bd oxidase, and that H2S reverses •NO-mediated inhibition of Mtb respiration. Further, exposure of Mtb to H2S regulates genes involved in sulfur and copper metabolism and the Dos regulon. Our results indicate that Mtb exploits host-derived H2S to promote growth and disease, and suggest that host-directed therapies targeting H2S production may be potentially useful for the management of tuberculosis and other microbial infections. The importance of host-produced hydrogen sulfide (H2S) in microbial pathogenesis is poorly understood. Here, Saini et al. show that H2S alters Mycobacterium tuberculosis (Mtb) central metabolism, stimulates respiration to promote growth and TB disease, and upregulates the Dos regulon.
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Affiliation(s)
- Vikram Saini
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA.,Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA.,Laboratory of Infection Biology and Translational Research, Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Krishna C Chinta
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Vineel P Reddy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joel N Glasgow
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Asaf Stein
- Department of Environment Health Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dirk A Lamprecht
- Africa Health Research Institute, Durban, South Africa.,Janssen Infectious Diseases and Vaccines, Janssen Pharmaceutica NV, Beerse, Belgium
| | | | | | | | | | | | - Shannon M Bailey
- Department of Environment Health Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Douglas R Moellering
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA.,Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jack R Lancaster
- Departments of Pharmacology and Chemical Biology, Medicine, and Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Adrie J C Steyn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA. .,Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA. .,Africa Health Research Institute, Durban, South Africa. .,Center for AIDS Research, University of Alabama at Birmingham, Birmingham, AL, USA.
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Maarsingh JD, Yang S, Park JG, Haydel SE. Comparative transcriptomics reveals PrrAB-mediated control of metabolic, respiration, energy-generating, and dormancy pathways in Mycobacterium smegmatis. BMC Genomics 2019; 20:942. [PMID: 31810444 PMCID: PMC6898941 DOI: 10.1186/s12864-019-6105-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 09/13/2019] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Mycobacterium smegmatis is a saprophytic bacterium frequently used as a genetic surrogate to study pathogenic Mycobacterium tuberculosis. The PrrAB two-component genetic regulatory system is essential in M. tuberculosis and represents an attractive therapeutic target. In this study, transcriptomic analysis (RNA-seq) of an M. smegmatis ΔprrAB mutant was used to define the PrrAB regulon and provide insights into the essential nature of PrrAB in M. tuberculosis. RESULTS RNA-seq differential expression analysis of M. smegmatis wild-type (WT), ΔprrAB mutant, and complementation strains revealed that during in vitro exponential growth, PrrAB regulates 167 genes (q < 0.05), 57% of which are induced in the WT background. Gene ontology and cluster of orthologous groups analyses showed that PrrAB regulates genes participating in ion homeostasis, redox balance, metabolism, and energy production. PrrAB induced transcription of dosR (devR), a response regulator gene that promotes latent infection in M. tuberculosis and 21 of the 25 M. smegmatis DosRS regulon homologues. Compared to the WT and complementation strains, the ΔprrAB mutant exhibited an exaggerated delayed growth phenotype upon exposure to potassium cyanide and respiratory inhibition. Gene expression profiling correlated with these growth deficiency results, revealing that PrrAB induces transcription of the high-affinity cytochrome bd oxidase genes under both aerobic and hypoxic conditions. ATP synthesis was ~ 64% lower in the ΔprrAB mutant relative to the WT strain, further demonstrating that PrrAB regulates energy production. CONCLUSIONS The M. smegmatis PrrAB two-component system regulates respiratory and oxidative phosphorylation pathways, potentially to provide tolerance against the dynamic environmental conditions experienced in its natural ecological niche. PrrAB positively regulates ATP levels during exponential growth, presumably through transcriptional activation of both terminal respiratory branches (cytochrome c bc1-aa3 and cytochrome bd oxidases), despite transcriptional repression of ATP synthase genes. Additionally, PrrAB positively regulates expression of the dormancy-associated dosR response regulator genes in an oxygen-independent manner, which may serve to fine-tune sensory perception of environmental stimuli associated with metabolic repression.
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Affiliation(s)
- Jason D Maarsingh
- School of Life Sciences, Arizona State University, Tempe, AZ, USA.,Department of Obstetrics and Gynecology, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ, USA
| | - Shanshan Yang
- Bioinformatics Core, Knowledge Enterprise Development, Arizona State University, Tempe, AZ, USA
| | - Jin G Park
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics, Arizona State University, Tempe, AZ, USA
| | - Shelley E Haydel
- School of Life Sciences, Arizona State University, Tempe, AZ, USA. .,The Biodesign Institute Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, AZ, USA.
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Roy KK, Wani MA. Emerging opportunities of exploiting mycobacterial electron transport chain pathway for drug-resistant tuberculosis drug discovery. Expert Opin Drug Discov 2019; 15:231-241. [PMID: 31774006 DOI: 10.1080/17460441.2020.1696771] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Introduction: Tuberculosis (TB) is a leading infectious disease worldwide whose chemotherapy is challenged by the continued rise of drug resistance. This epidemic urges the need to discover anti-TB drugs with novel modes of action.Areas covered: The mycobacterial electron transport chain (ETC) pathway represents a hub of anti-TB drug targets. Herein, the authors highlight the various targets within the mycobacterial ETC and highlight some of the promising ETC-targeted drugs and clinical candidates that have been discovered or repurposed. Furthermore, recent breakthroughs in the availability of X-ray and/or cryo-EM structures of some targets are discussed, and various opportunities of exploiting these structures for the discovery of new anti-TB drugs are emphasized.Expert opinion: The drug discovery efforts targeting the ETC pathway have led to the FDA approval of bedaquiline, a FOF1-ATP synthase inhibitor, and the discovery of Q203, a clinical candidate drug targeting the mycobacterial cytochrome bcc-aa3 supercomplex. Moreover, clofazimine, a proposed prodrug competing with menaquinone for its reduction by mycobacterial NADH dehydrogenase 2, has been repurposed for TB treatment. Recently available structures of the mycobacterial ATP synthase C9 rotary ring and the cytochrome bcc-aa3 supercomplex represent further opportunities for the structure-based drug design (SBDD) of the next-generation of inhibitors against Mycobacterium tuberculosis.
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Affiliation(s)
- Kuldeep K Roy
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Kolkata, India
| | - Mushtaq Ahmad Wani
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Kolkata, India
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Mascolo L, Bald D. Cytochrome bd in Mycobacterium tuberculosis: A respiratory chain protein involved in the defense against antibacterials. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 152:55-63. [PMID: 31738981 DOI: 10.1016/j.pbiomolbio.2019.11.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/12/2019] [Indexed: 12/27/2022]
Abstract
The branched respiratory chain of Mycobacterium tuberculosis has attracted attention as a highly promising target for next-generation antibacterials. This system includes two terminal oxidases of which the exclusively bacterial cytochrome bd represents the less energy-efficient one. Albeit dispensable for growth under standard laboratory conditions, cytochrome bd is important during environmental stress. In this review, we discuss the role of cytochrome bd during infection of the mammalian host and in the defense against antibacterials. Deeper insight into the biochemistry of mycobacterial cytochrome bd is needed to understand the physiological role of this bacteria-specific defense factor. Conversely, cytochrome bd may be utilized to gain information on mycobacterial physiology in vitro and during host infection. Knowledge-based manipulation of cytochrome bd function may assist in designing the next-generation tuberculosis combination chemotherapy.
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Affiliation(s)
- Ludovica Mascolo
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
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Abstract
The global tuberculosis (TB) epidemic has been exacerbated by the rise in drug-resistant TB cases worldwide. To tackle this crisis, it is necessary to identify new vulnerable drug targets in Mycobacterium tuberculosis, the causative agent of TB, and develop compounds that can inhibit the bacterium through novel mechanisms of action. The QcrB subunit of the electron transport chain enzyme cytochrome bc1 has recently been validated to be a potential drug target. In the current work, we report the discovery of a new class of QcrB inhibitors, 4-amino-thieno[2,3-d]pyrimidines, that potently inhibit M. tuberculosis growth in vitro. These compounds are chemically distinct from previously reported QcrB inhibitors, and therefore, 4-amino-thieno[2,3-d]pyrimidines represent a new scaffold that can be exploited to inhibit this drug target. Antibiotic resistance is a global crisis that threatens our ability to treat bacterial infections, such as tuberculosis, caused by Mycobacterium tuberculosis. Of the 10 million cases of tuberculosis in 2017, approximately 19% of new cases and 43% of previously treated cases were caused by strains of M. tuberculosis resistant to at least one frontline antibiotic. There is a clear need for new therapies that target these genetically resistant strains. Here, we report the discovery of a new series of antimycobacterial compounds, 4-amino-thieno[2,3-d]pyrimidines, that potently inhibit the growth of M. tuberculosis. To elucidate the mechanism by which these compounds inhibit M. tuberculosis, we selected for mutants resistant to a representative 4-amino-thieno[2,3-d]pyrimidine and sequenced these strains to identify the mutations that confer resistance. We isolated a total of 12 resistant mutants, each of which harbored a nonsynonymous mutation in the gene qcrB, which encodes a subunit of the electron transport chain (ETC) enzyme cytochrome bc1 oxidoreductase, leading us to hypothesize that 4-amino-thieno[2,3-d]pyrimidines target this enzyme complex. We found that addition of 4-amino-thieno[2,3-d]pyrimidines to M. tuberculosis cultures resulted in a decrease in ATP levels, supporting our model that these compounds inhibit the M. tuberculosis ETC. Furthermore, 4-amino-thieno[2,3-d]pyrimidines had enhanced activity against a mutant of M. tuberculosis deficient in cytochrome bd oxidase, which is a hallmark of cytochrome bc1 inhibitors. Therefore, 4-amino-thieno[2,3-d]pyrimidines represent a novel series of QcrB inhibitors that build on the growing number of chemical scaffolds that are able to inhibit the mycobacterial cytochrome bc1 complex. IMPORTANCE The global tuberculosis (TB) epidemic has been exacerbated by the rise in drug-resistant TB cases worldwide. To tackle this crisis, it is necessary to identify new vulnerable drug targets in Mycobacterium tuberculosis, the causative agent of TB, and develop compounds that can inhibit the bacterium through novel mechanisms of action. The QcrB subunit of the electron transport chain enzyme cytochrome bc1 has recently been validated to be a potential drug target. In the current work, we report the discovery of a new class of QcrB inhibitors, 4-amino-thieno[2,3-d]pyrimidines, that potently inhibit M. tuberculosis growth in vitro. These compounds are chemically distinct from previously reported QcrB inhibitors, and therefore, 4-amino-thieno[2,3-d]pyrimidines represent a new scaffold that can be exploited to inhibit this drug target.
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40
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Isoniazid Bactericidal Activity Involves Electron Transport Chain Perturbation. Antimicrob Agents Chemother 2019; 63:AAC.01841-18. [PMID: 30642937 DOI: 10.1128/aac.01841-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/03/2019] [Indexed: 12/23/2022] Open
Abstract
Accumulating evidence suggests that the bactericidal activity of some antibiotics may not be directly initiated by target inhibition. The activity of isoniazid (INH), a key first-line bactericidal antituberculosis drug currently known to inhibit mycolic acid synthesis, becomes extremely poor under stress conditions, such as hypoxia and starvation. This suggests that the target inhibition may not fully explain the bactericidal activity of the drug. Here, we report that INH rapidly increased Mycobacterium bovis BCG cellular ATP levels and enhanced oxygen consumption. The INH-triggered ATP increase and bactericidal activity were strongly compromised by Q203 and bedaquiline, which inhibit mycobacterial cytochrome bc 1 and FoF1 ATP synthase, respectively. Moreover, the antioxidant N-acetylcysteine (NAC) but not 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL) abrogated the INH-triggered ATP increase and killing. These results reveal a link between the energetic (ATP) perturbation and INH's killing. Furthermore, the INH-induced energetic perturbation and killing were also abrogated by chemical inhibition of NADH dehydrogenases (NDHs) and succinate dehydrogenases (SDHs), linking INH's bactericidal activity further to the electron transport chain (ETC) perturbation. This notion was also supported by the observation that INH dissipated mycobacterial membrane potential. Importantly, inhibition of cytochrome bd oxidase significantly reduced cell recovery during INH challenge in a culture settling model, suggesting that the respiratory reprogramming to the cytochrome bd oxidase contributes to the escape of INH killing. This study implicates mycobacterial ETC perturbation through NDHs, SDHs, cytochrome bc 1, and FoF1 ATP synthase in INH's bactericidal activity and pinpoints the participation of the cytochrome bd oxidase in protection against this drug under stress conditions.
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Hards K, Rodriguez SM, Cairns C, Cook GM. Alternate quinone coupling in a new class of succinate dehydrogenase may potentiate mycobacterial respiratory control. FEBS Lett 2019; 593:475-486. [DOI: 10.1002/1873-3468.13330] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 01/16/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Kiel Hards
- Department of Microbiology and Immunology University of Otago Dunedin New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery The University of Auckland New Zealand
| | | | - Charlotte Cairns
- 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 The University of Auckland New Zealand
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Alanine dehydrogenases in mycobacteria. J Microbiol 2019; 57:81-92. [PMID: 30706339 DOI: 10.1007/s12275-019-8543-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 10/31/2018] [Accepted: 11/07/2018] [Indexed: 10/27/2022]
Abstract
Since NAD(H)-dependent L-alanine dehydrogenase (EC 1.1.4.1; Ald) was identified as one of the major antigens present in culture filtrates of Mycobacterium tuberculosis, many studies on the enzyme have been conducted. Ald catalyzes the reversible conversion of pyruvate to alanine with concomitant oxidation of NADH to NAD+ and has a homohexameric quaternary structure. Expression of the ald genes was observed to be strongly upregulated in M. tuberculosis and Mycobacterium smegmatis grown in the presence of alanine. Furthermore, expression of the ald genes in some mycobacteria was observed to increase under respiration-inhibitory conditions such as oxygen-limiting and nutrient-starvation conditions. Upregulation of ald expression by alanine or under respiration-inhibitory conditions is mediated by AldR, a member of the Lrp/AsnC family of transcriptional regulators. Mycobacterial Alds were demonstrated to be the enzymes required for utilization of alanine as a nitrogen source and to help mycobacteria survive under respiration-inhibitory conditions by maintaining cellular NADH/NAD+ homeostasis. Several inhibitors of Ald have been developed, and their application in combination with respiration-inhibitory antitubercular drugs such as Q203 and bedaquiline was recently suggested.
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Cytochrome bd Oxidase Has an Important Role in Sustaining Growth and Development of Streptomyces coelicolor A3(2) under Oxygen-Limiting Conditions. J Bacteriol 2018; 200:JB.00239-18. [PMID: 29784883 DOI: 10.1128/jb.00239-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/14/2018] [Indexed: 11/20/2022] Open
Abstract
Streptomyces coelicolor A3(2) is a filamentously growing, spore-forming, obligately aerobic actinobacterium that uses both a copper aa3 -type cytochrome c oxidase and a cytochrome bd oxidase to respire oxygen. Using defined knockout mutants, we demonstrated that either of these terminal oxidases was capable of allowing the bacterium to grow and complete its developmental cycle. The genes encoding the bcc complex and the aa3 oxidase are clustered at a single locus. Using Western blot analyses, we showed that the bcc-aa3 oxidase branch is more prevalent in spores than the bd oxidase. The level of the catalytic subunit, CydA, of the bd oxidase was low in spore extracts derived from the wild type, but it was upregulated in a mutant lacking the bcc-aa3 supercomplex. This indicates that cytochrome bd oxidase can compensate for the lack of the other respiratory branch. Components of both oxidases were abundant in growing mycelium. Growth studies in liquid medium revealed that a mutant lacking the bcc-aa3 oxidase branch grew approximately half as fast as the wild type, while the oxygen reduction rate of the mutant remained close to that of the wild type, indicating that the bd oxidase was mainly functioning in controlling electron flux. Developmental defects were observed for a mutant lacking the cytochrome bd oxidase during growth on buffered rich medium plates with glucose as the energy substrate. Evidence based on using the redox-cycling dye methylene blue suggested that cytochrome bd oxidase is essential for the bacterium to grow and complete its developmental cycle under oxygen limitation.IMPORTANCE Respiring with oxygen is an efficient means of conserving energy in biological systems. The spore-forming, filamentous actinobacterium Streptomyces coelicolor grows only aerobically, synthesizing two enzyme complexes for O2 reduction, the cytochrome bcc-aa3 cytochrome oxidase supercomplex and the cytochrome bd oxidase. We show in this study that the bacterium can survive with either of these respiratory pathways to oxygen. Immunological studies indicate that the bcc-aa3 oxidase is the main oxidase present in spores, but the bd oxidase compensates if the bcc-aa3 oxidase is inactivated. Both oxidases are active in mycelia. Growth conditions were identified, revealing that cytochrome bd oxidase is essential for aerial hypha formation and sporulation, and this was linked to an important role of the enzyme under oxygen-limiting conditions.
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Roles of Alanine Dehydrogenase and Induction of Its Gene in Mycobacterium smegmatis under Respiration-Inhibitory Conditions. J Bacteriol 2018; 200:JB.00152-18. [PMID: 29712875 DOI: 10.1128/jb.00152-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/25/2018] [Indexed: 01/08/2023] Open
Abstract
Here we demonstrated that the inhibition of electron flux through the respiratory electron transport chain (ETC) by either the disruption of the gene for the major terminal oxidase (aa3 cytochrome c oxidase) or treatment with KCN resulted in the induction of ald encoding alanine dehydrogenase in Mycobacterium smegmatis A decrease in functionality of the ETC shifts the redox state of the NADH/NAD+ pool toward a more reduced state, which in turn leads to an increase in cellular levels of alanine by Ald catalyzing the conversion of pyruvate to alanine with the concomitant oxidation of NADH to NAD+ The induction of ald expression under respiration-inhibitory conditions in M. smegmatis is mediated by the alanine-responsive AldR transcriptional regulator. The growth defect of M. smegmatis by respiration inhibition was exacerbated by inactivation of the ald gene, suggesting that Ald is beneficial to M. smegmatis in its adaptation and survival under respiration-inhibitory conditions by maintaining NADH/NAD+ homeostasis. The low susceptibility of M. smegmatis to bcc1 complex inhibitors appears to be, at least in part, attributable to the high expression level of the bd quinol oxidase in M. smegmatis when the bcc1-aa3 branch of the ETC is inactivated.IMPORTANCE We demonstrated that the functionality of the respiratory electron transport chain is inversely related to the expression level of the ald gene encoding alanine dehydrogenase in Mycobacterium smegmatis Furthermore, the importance of Ald in NADH/NAD+ homeostasis during the adaptation of M. smegmatis to severe respiration-inhibitory conditions was demonstrated in this study. On the basis of these results, we propose that combinatory regimens including both an Ald-specific inhibitor and respiration-inhibitory antitubercular drugs such as Q203 and bedaquiline are likely to enable a more efficient therapy for tuberculosis.
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Iqbal IK, Bajeli S, Akela AK, Kumar A. Bioenergetics of Mycobacterium: An Emerging Landscape for Drug Discovery. Pathogens 2018; 7:E24. [PMID: 29473841 PMCID: PMC5874750 DOI: 10.3390/pathogens7010024] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 11/16/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) exhibits remarkable metabolic flexibility that enables it to survive a plethora of host environments during its life cycle. With the advent of bedaquiline for treatment of multidrug-resistant tuberculosis, oxidative phosphorylation has been validated as an important target and a vulnerable component of mycobacterial metabolism. Exploiting the dependence of Mtb on oxidative phosphorylation for energy production, several components of this pathway have been targeted for the development of new antimycobacterial agents. This includes targeting NADH dehydrogenase by phenothiazine derivatives, menaquinone biosynthesis by DG70 and other compounds, terminal oxidase by imidazopyridine amides and ATP synthase by diarylquinolines. Importantly, oxidative phosphorylation also plays a critical role in the survival of persisters. Thus, inhibitors of oxidative phosphorylation can synergize with frontline TB drugs to shorten the course of treatment. In this review, we discuss the oxidative phosphorylation pathway and development of its inhibitors in detail.
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Affiliation(s)
- Iram Khan Iqbal
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh 160036, India.
| | - Sapna Bajeli
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh 160036, India.
| | - Ajit Kumar Akela
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh 160036, India.
| | - Ashwani Kumar
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh 160036, India.
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Lu P, Asseri AH, Kremer M, Maaskant J, Ummels R, Lill H, Bald D. The anti-mycobacterial activity of the cytochrome bcc inhibitor Q203 can be enhanced by small-molecule inhibition of cytochrome bd. Sci Rep 2018; 8:2625. [PMID: 29422632 PMCID: PMC5805707 DOI: 10.1038/s41598-018-20989-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/23/2018] [Indexed: 11/09/2022] Open
Abstract
Mycobacterial energy metabolism currently attracts strong attention as new target space for development of anti-tuberculosis drugs. The imidazopyridine Q203 targets the cytochrome bcc complex of the respiratory chain, a key component in energy metabolism. Q203 blocks growth of Mycobacterium tuberculosis at nanomolar concentrations, however, it fails to actually kill the bacteria, which may limit the clinical applicability of this candidate drug. In this report we show that inhibition of cytochrome bd, a parallel branch of the mycobacterial respiratory chain, by aurachin D invoked bactericidal activity of Q203. In biochemical assays using inverted membrane vesicles from Mycobacterium tuberculosis and Mycobacterium smegmatis we found that inhibition of respiratory chain activity by Q203 was incomplete, but could be enhanced by inactivation of cytochrome bd, either by genetic knock-out or by inhibition with aurachin D. These results indicate that simultaneously targeting the cytochrome bcc and the cytochrome bd branch of the mycobacterial respiratory chain may turn out as effective strategy for combating M. tuberculosis.
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Affiliation(s)
- Ping Lu
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Amer H Asseri
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.,Biochemsitry Department, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Martijn Kremer
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Janneke Maaskant
- Department of Medical Microbiology and Infection Control, VU university Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Roy Ummels
- Department of Medical Microbiology and Infection Control, VU university Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Holger Lill
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
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Abstract
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Current tuberculosis
(TB) drug development efforts are not sufficient
to end the global TB epidemic. Recent efforts have focused on the
development of whole-cell screening assays because biochemical, target-based
inhibitor screens during the last two decades have not delivered new
TB drugs. Mycobacterium tuberculosis (Mtb), the causative
agent of TB, encounters diverse microenvironments and can be found
in a variety of metabolic states in the human host. Due to the complexity
and heterogeneity of Mtb infection, no single model can fully recapitulate
the in vivo conditions in which Mtb is found in TB patients, and there
is no single “standard” screening condition to generate
hit compounds for TB drug development. However, current screening
assays have become more sophisticated as researchers attempt to mirror
the complexity of TB disease in the laboratory. In this review, we
describe efforts using surrogates and engineered strains of Mtb to
focus screens on specific targets. We explain model culture systems
ranging from carbon starvation to hypoxia, and combinations thereof,
designed to represent the microenvironment which Mtb encounters in
the human body. We outline ongoing efforts to model Mtb infection
in the lung granuloma. We assess these different models, their ability
to generate hit compounds, and needs for further TB drug development,
to provide direction for future TB drug discovery.
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Affiliation(s)
- Tianao Yuan
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States
| | - Nicole S Sampson
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States.,Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University , Stellenbosch 7600, South Africa
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48
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Combinations of Respiratory Chain Inhibitors Have Enhanced Bactericidal Activity against Mycobacterium tuberculosis. Antimicrob Agents Chemother 2017; 62:AAC.01677-17. [PMID: 29061760 PMCID: PMC5740367 DOI: 10.1128/aac.01677-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/17/2017] [Indexed: 11/20/2022] Open
Abstract
As an obligate aerobe, Mycobacterium tuberculosis uses its electron transport chain (ETC) to produce energy via oxidative phosphorylation. This pathway has recently garnered a lot of attention and is a target for several new antimycobacterials. We tested the respiratory adaptation of M. tuberculosis to phenoxyalkylbenzimidazoles (PABs), compounds proposed to target QcrB, a component of the cytochrome bc1 complex. We show that M. tuberculosis is able to reroute its ETC to provide temporary resistance to PABs. However, combination treatment of PAB with agents targeting other components of the electron transport chain overcomes this respiratory flexibility. PAB in combination with clofazimine resulted in synergistic killing of M. tuberculosis under both replicating and nonreplicating conditions. PABs in combination with bedaquiline demonstrated antagonism at early time points, particularly under nonreplicating conditions. However, this antagonistic effect disappeared within 3 weeks, when PAB-BDQ combinations became highly bactericidal; in some cases, they were better than either drug alone. This study highlights the potential for combination treatment targeting the ETC and supports the development of PABs as part of a novel drug regimen against M. tuberculosis.
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49
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Oxidative Phosphorylation as a Target Space for Tuberculosis: Success, Caution, and Future Directions. Microbiol Spectr 2017; 5. [PMID: 28597820 DOI: 10.1128/microbiolspec.tbtb2-0014-2016] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The emergence and spread of drug-resistant pathogens, and our inability to develop new antimicrobials to combat resistance, have inspired scientists to seek out new targets for drug development. The Mycobacterium tuberculosis complex is a group of obligately aerobic bacteria that have specialized for inhabiting a wide range of intracellular and extracellular environments. Two fundamental features in this adaptation are the flexible utilization of energy sources and continued metabolism in the absence of growth. M. tuberculosis is an obligately aerobic heterotroph that depends on oxidative phosphorylation for growth and survival. However, several studies are redefining the metabolic breadth of the genus. Alternative electron donors and acceptors may provide the maintenance energy for the pathogen to maintain viability in hypoxic, nonreplicating states relevant to latent infection. This hidden metabolic flexibility may ultimately decrease the efficacy of drugs targeted against primary dehydrogenases and terminal oxidases. However, it may also open up opportunities to develop novel antimycobacterials targeting persister cells. In this review, we discuss the progress in understanding the role of energetic targets in mycobacterial physiology and pathogenesis and the opportunities for drug discovery.
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50
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Boot M, Jim KK, Liu T, Commandeur S, Lu P, Verboom T, Lill H, Bitter W, Bald D. A fluorescence-based reporter for monitoring expression of mycobacterial cytochrome bd in response to antibacterials and during infection. Sci Rep 2017; 7:10665. [PMID: 28878275 PMCID: PMC5587683 DOI: 10.1038/s41598-017-10944-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 08/16/2017] [Indexed: 12/16/2022] Open
Abstract
Cytochrome bd is a component of the oxidative phosphorylation pathway in many Gram-positive and Gram-negative bacteria. Next to its role as a terminal oxidase in the respiratory chain this enzyme plays an important role as a survival factor in the bacterial stress response. In Mycobacterium tuberculosis and related mycobacterial strains, cytochrome bd is an important component of the defense system against antibacterial drugs. In this report we describe and evaluate an mCherry-based fluorescent reporter for detection of cytochrome bd expression in Mycobacterium marinum. Cytochrome bd was induced by mycolic acid biosynthesis inhibitors such as isoniazid and most prominently by drugs targeting oxidative phosphorylation. We observed no induction by inhibitors of protein-, DNA- or RNA-synthesis. The constructed expression reporter was suitable for monitoring mycobacterial cytochrome bd expression during mouse macrophage infection and in a zebrafish embryo infection model when using Mycobacterium marinum. Interestingly, in both these infection models cytochrome bd levels were considerably higher than during in vitro culturing of M. marinum. The expression reporter described here can be a valuable tool for elucidating the role of cytochrome bd as a survival factor.
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Affiliation(s)
- Maikel Boot
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Kin Ki Jim
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Ting Liu
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Susanna Commandeur
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Ping Lu
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Theo Verboom
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Holger Lill
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.,Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
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