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Yoshizumi T, Shibui Y, Kogo M, Honma S, Ito S, Yajima S, Sasaki Y. Mycothiol maintains the homeostasis and signalling of nitric oxide in Streptomyces coelicolor A3(2) M145. BMC Microbiol 2023; 23:285. [PMID: 37798648 PMCID: PMC10552308 DOI: 10.1186/s12866-023-03036-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 10/01/2023] [Indexed: 10/07/2023] Open
Abstract
BACKGROUND Previous studies have revealed a nitric oxide (NO) metabolic cycle in which NO, nitrate (NO3-), and nitrite (NO2-) circulate. The NO produced in this cycle serves as a signalling molecule that regulates actinorhodin (ACT) production via the DevS/DevR NO-dependent two-component system (TCS) in Streptomyces coelicolor A3(2) M145. However, the mechanisms involved in the regulation of NO signalling in S. coelicolor have not yet been elucidated. Mycothiol (MSH), a thiol molecule produced by Actinomyces, is involved in the defence mechanisms against oxidative stress. Therefore, this study focused on the correlation between intracellular NO and MSH levels. RESULTS To investigate the interaction of MSH with endogenously produced NO, we generated an S. coelicolor A3(2) strain deficient in MSH biosynthesis. This mutant strain exhibited a decrease in low-molecular-weight S-nitrosothiols and intracellular NO levels during culture compared to those of the wild-type strain. Moreover, the mutant strain exhibited reduced activity of the DevS/DevR TCS, a regulator of NO homeostasis and ACT production, from the early stage of culture, along with a decrease in ACT production compared to those of the wild-type strain. CONCLUSIONS This study suggests that MSH maintains intracellular NO homeostasis by forming S-nitrosomycothiol, which induces NO signalling. Finally, we propose a metabolic model in which MSH from endogenously produced NO facilitates the maintenance of both NO homeostasis and signalling in S. coelicolor A3(2) M145.
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Affiliation(s)
- Tomoki Yoshizumi
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Sakuragaoka, Tokyo, Setagaya-Ku, 156-8502, Japan
| | - Yukiko Shibui
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Sakuragaoka, Tokyo, Setagaya-Ku, 156-8502, Japan
| | - Minori Kogo
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Sakuragaoka, Tokyo, Setagaya-Ku, 156-8502, Japan
| | - Sota Honma
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Sakuragaoka, Tokyo, Setagaya-Ku, 156-8502, Japan
| | - Shinsaku Ito
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Sakuragaoka, Tokyo, Setagaya-Ku, 156-8502, Japan
| | - Shunsuke Yajima
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Sakuragaoka, Tokyo, Setagaya-Ku, 156-8502, Japan
| | - Yasuyuki Sasaki
- Department of Bioscience, Faculty of Life Sciences, Tokyo University of Agriculture, Sakuragaoka, Tokyo, Setagaya-Ku, 156-8502, Japan.
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Larkins-Ford J, Greenstein T, Van N, Degefu YN, Olson MC, Sokolov A, Aldridge BB. Systematic measurement of combination-drug landscapes to predict in vivo treatment outcomes for tuberculosis. Cell Syst 2021; 12:1046-1063.e7. [PMID: 34469743 PMCID: PMC8617591 DOI: 10.1016/j.cels.2021.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/16/2021] [Accepted: 08/04/2021] [Indexed: 12/30/2022]
Abstract
Lengthy multidrug chemotherapy is required to achieve a durable cure in tuberculosis. However, we lack well-validated, high-throughput in vitro models that predict animal outcomes. Here, we provide an extensible approach to rationally prioritize combination therapies for testing in in vivo mouse models of tuberculosis. We systematically measured Mycobacterium tuberculosis response to all two- and three-drug combinations among ten antibiotics in eight conditions that reproduce lesion microenvironments, resulting in >500,000 measurements. Using these in vitro data, we developed classifiers predictive of multidrug treatment outcome in a mouse model of disease relapse and identified ensembles of in vitro models that best describe in vivo treatment outcomes. We identified signatures of potencies and drug interactions in specific in vitro models that distinguish whether drug combinations are better than the standard of care in two important preclinical mouse models. Our framework is generalizable to other difficult-to-treat diseases requiring combination therapies. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Jonah Larkins-Ford
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA; Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Boston, MA 02111, USA; Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA; Laboratory of Systems Pharmacology, Harvard Program in Therapeutic Science, Harvard Medical School, Boston, MA 02115, USA
| | - Talia Greenstein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA; Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Boston, MA 02111, USA; Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Nhi Van
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Yonatan N Degefu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA; Laboratory of Systems Pharmacology, Harvard Program in Therapeutic Science, Harvard Medical School, Boston, MA 02115, USA
| | - Michaela C Olson
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Artem Sokolov
- Laboratory of Systems Pharmacology, Harvard Program in Therapeutic Science, Harvard Medical School, Boston, MA 02115, USA
| | - Bree B Aldridge
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA; Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Boston, MA 02111, USA; Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA; Laboratory of Systems Pharmacology, Harvard Program in Therapeutic Science, Harvard Medical School, Boston, MA 02115, USA; Department of Biomedical Engineering, Tufts University School of Engineering, Medford, MA 02155, USA.
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3
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Zhong Q, Kobe B, Kappler U. Molybdenum Enzymes and How They Support Virulence in Pathogenic Bacteria. Front Microbiol 2020; 11:615860. [PMID: 33362753 PMCID: PMC7759655 DOI: 10.3389/fmicb.2020.615860] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022] Open
Abstract
Mononuclear molybdoenzymes are highly versatile catalysts that occur in organisms in all domains of life, where they mediate essential cellular functions such as energy generation and detoxification reactions. Molybdoenzymes are particularly abundant in bacteria, where over 50 distinct types of enzymes have been identified to date. In bacterial pathogens, all aspects of molybdoenzyme biology such as molybdate uptake, cofactor biosynthesis, and function of the enzymes themselves, have been shown to affect fitness in the host as well as virulence. Although current studies are mostly focused on a few key pathogens such as Escherichia coli, Salmonella enterica, Campylobacter jejuni, and Mycobacterium tuberculosis, some common themes for the function and adaptation of the molybdoenzymes to pathogen environmental niches are emerging. Firstly, for many of these enzymes, their role is in supporting bacterial energy generation; and the corresponding pathogen fitness and virulence defects appear to arise from a suboptimally poised metabolic network. Secondly, all substrates converted by virulence-relevant bacterial Mo enzymes belong to classes known to be generated in the host either during inflammation or as part of the host signaling network, with some enzyme groups showing adaptation to the increased conversion of such substrates. Lastly, a specific adaptation to bacterial in-host survival is an emerging link between the regulation of molybdoenzyme expression in bacterial pathogens and the presence of immune system-generated reactive oxygen species. The prevalence of molybdoenzymes in key bacterial pathogens including ESKAPE pathogens, paired with the mounting evidence of their central roles in bacterial fitness during infection, suggest that they could be important future drug targets.
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Affiliation(s)
- Qifeng Zhong
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia
| | - Bostjan Kobe
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia.,Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | - Ulrike Kappler
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia
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4
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Unden G, Klein R. Sensing of O 2 and nitrate by bacteria: alternative strategies for transcriptional regulation of nitrate respiration by O 2 and nitrate. Environ Microbiol 2020; 23:5-14. [PMID: 33089915 DOI: 10.1111/1462-2920.15293] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/28/2022]
Abstract
Many bacteria are able to use O2 and nitrate as alternative electron acceptors for respiration. Strategies for regulation in response to O2 and nitrate can vary considerably. In the paradigmatic system of E. coli (and γ-proteobacteria), regulation by O2 and nitrate is established by the O2 -sensor FNR and the two-component system NarX-NarL (for nitrate regulation). Expression of narGHJI is regulated by the binding of FNR and NarL to the promoter. A similar strategy by individual regulation in response to O2 and nitrate is verified in many genera by the use of various types of regulators. Otherwise, in the soil bacteria Bacillus subtilis (Firmicutes) and Streptomyces (Actinobacteria), nitrate respiration is subject to anaerobic induction, without direct nitrate induction. In contrast, the NreA-NreB-NreC two-component system of Staphylococcus (Firmicutes) performs joint sensing of O2 and nitrate by interacting O2 and nitrate sensors. The O2 -sensor NreB phosphorylates the response regulator NreC to activate narGHJI expression. NreC-P transmits the signal for anaerobiosis to the promoter. The nitrate sensor NreA modulates NreB function by converting NreB in the absence of nitrate from the kinase to a phosphatase that dephosphorylates NreC-P. Thus, widely different strategies for coordinating the response to O2 and nitrate have evolved in bacteria.
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Affiliation(s)
- Gottfried Unden
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, 55099, Germany
| | - Robin Klein
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, 55099, Germany
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5
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Potential therapeutic approaches for a sleeping pathogen: tuberculosis a case for bioinorganic chemistry. J Biol Inorg Chem 2020; 25:685-704. [PMID: 32676771 DOI: 10.1007/s00775-020-01803-1] [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: 04/24/2020] [Accepted: 06/30/2020] [Indexed: 12/18/2022]
Abstract
Mycobacterium tuberculosis (Mtb) has an old history as a human pathogen and still kills over one million people every year. One key feature of this bacterium is its dormancy: a phenomenon responsible for major changes in its metabolism and replication that have been associated with the need for a lengthy therapy for Mtb. This process is regulated by key heme-based sensors, particularly DosT and DevS (DosS), among other co-regulators, and also linked to nitrogen utilization (nitrate/nitrite) and stringent responses. In face of the current threat of tuberculosis, there is an urgent need to develop new therapeutic agents capable of targeting the dormant state, associated with the need for a lengthy therapy. Interestingly, many of those key proteins are indeed metallo-containing or metallo-dependent biomolecules, opening exciting bioinorganic opportunities. Here, we critically reviewed a series of small molecules targeting key proteins involved in these processes, including DosT/DevS/DevR, RegX3, MprA, MtrA, NarL, PknB, Rel, PPK, nitrate and nitrite reductases, GlnA1, aiming for new opportunities and alternative therapies. In the battle against Mycobacterium tuberculosis, new drug targets must be searched, in particular those involved in dormancy. A series of exciting cases for drug development involving metallo-containing or metallo-dependent biomolecules are reviewed, opening great opportunities for the bioinorganic chemistry community.
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6
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The Mycobacterium tuberculosis Pup-proteasome system regulates nitrate metabolism through an essential protein quality control pathway. Proc Natl Acad Sci U S A 2019; 116:3202-3210. [PMID: 30723150 DOI: 10.1073/pnas.1819468116] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The human pathogen Mycobacterium tuberculosis encodes a proteasome that carries out regulated degradation of bacterial proteins. It has been proposed that the proteasome contributes to nitrogen metabolism in M. tuberculosis, although this hypothesis had not been tested. Upon assessing M. tuberculosis growth in several nitrogen sources, we found that a mutant strain lacking the Mycobacterium proteasomal activator Mpa was unable to use nitrate as a sole nitrogen source due to a specific failure in the pathway of nitrate reduction to ammonium. We found that the robust activity of the nitrite reductase complex NirBD depended on expression of the groEL/groES chaperonin genes, which are regulated by the repressor HrcA. We identified HrcA as a likely proteasome substrate, and propose that the degradation of HrcA is required for the full expression of chaperonin genes. Furthermore, our data suggest that degradation of HrcA, along with numerous other proteasome substrates, is enhanced during growth in nitrate to facilitate the derepression of the chaperonin genes. Importantly, growth in nitrate is an example of a specific condition that reduces the steady-state levels of numerous proteasome substrates in M. tuberculosis.
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7
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Galizia J, Acosta MP, Urdániz E, Martí MA, Piuri M. Evaluation of nitroxyl donors' effect on mycobacteria. Tuberculosis (Edinb) 2018; 109:35-40. [DOI: 10.1016/j.tube.2018.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/26/2017] [Accepted: 01/30/2018] [Indexed: 10/18/2022]
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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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9
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Jamaati H, Mortaz E, Pajouhi Z, Folkerts G, Movassaghi M, Moloudizargari M, Adcock IM, Garssen J. Nitric Oxide in the Pathogenesis and Treatment of Tuberculosis. Front Microbiol 2017; 8:2008. [PMID: 29085351 PMCID: PMC5649180 DOI: 10.3389/fmicb.2017.02008] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/29/2017] [Indexed: 12/21/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is globally known as one of the most important human pathogens. Mtb is estimated to infect nearly one third of the world's population with many subjects having a latent infection. Thus, from an estimated 2 billion people infected with Mtb, less than 10% may develop symptomatic TB. This indicates that the host immune system may constrain pathogen replication in most infected individuals. On entering the lungs of the host, Mtb initially encounters resident alveolar macrophages which can engulf and subsequently eliminate intracellular microbes via a plethora of bactericidal mechanisms including the generation of free radicals such as reactive oxygen and nitrogen species. Nitric oxide (NO), a key anti-mycobacterial molecule, is detected in the exhaled breath of patients infected with Mtb. Recent knowledge regarding the regulatory role of NO in airway function and Mtb proliferation paves the way of exploiting the beneficial effects of this molecule for the treatment of airway diseases. Here, we discuss the importance of NO in the pathogenesis of TB, the diagnostic use of exhaled and urinary NO in Mtb infection and the potential of NO-based treatments.
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Affiliation(s)
- Hamidreza Jamaati
- Chronic Respiratory Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Esmaeil Mortaz
- Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Zeinab Pajouhi
- Chronic Respiratory Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Gert Folkerts
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Mehrnaz Movassaghi
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Milad Moloudizargari
- Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ian M Adcock
- Cell and Molecular Biology Group, Airways Disease Section, Faculty of Medicine, National Heart and Lung Institute, Imperial College London, London, United Kingdom.,Priority Research Centre for Asthma and Respiratory Disease, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia
| | - Johan Garssen
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands.,Nutricia Research Centre for Specialized Nutrition, Utrecht, Netherlands
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Gold B, Nathan C. Targeting Phenotypically Tolerant Mycobacterium tuberculosis. Microbiol Spectr 2017; 5:10.1128/microbiolspec.TBTB2-0031-2016. [PMID: 28233509 PMCID: PMC5367488 DOI: 10.1128/microbiolspec.tbtb2-0031-2016] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Indexed: 01/08/2023] Open
Abstract
While the immune system is credited with averting tuberculosis in billions of individuals exposed to Mycobacterium tuberculosis, the immune system is also culpable for tempering the ability of antibiotics to deliver swift and durable cure of disease. In individuals afflicted with tuberculosis, host immunity produces diverse microenvironmental niches that support suboptimal growth, or complete growth arrest, of M. tuberculosis. The physiological state of nonreplication in bacteria is associated with phenotypic drug tolerance. Many of these host microenvironments, when modeled in vitro by carbon starvation, complete nutrient starvation, stationary phase, acidic pH, reactive nitrogen intermediates, hypoxia, biofilms, and withholding streptomycin from the streptomycin-addicted strain SS18b, render M. tuberculosis profoundly tolerant to many of the antibiotics that are given to tuberculosis patients in clinical settings. Targeting nonreplicating persisters is anticipated to reduce the duration of antibiotic treatment and rate of posttreatment relapse. Some promising drugs to treat tuberculosis, such as rifampin and bedaquiline, only kill nonreplicating M. tuberculosisin vitro at concentrations far greater than their minimal inhibitory concentrations against replicating bacilli. There is an urgent demand to identify which of the currently used antibiotics, and which of the molecules in academic and corporate screening collections, have potent bactericidal action on nonreplicating M. tuberculosis. With this goal, we review methods of high-throughput screening to target nonreplicating M. tuberculosis and methods to progress candidate molecules. A classification based on structures and putative targets of molecules that have been reported to kill nonreplicating M. tuberculosis revealed a rich diversity in pharmacophores.
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Affiliation(s)
- Ben Gold
- Department of Microbiology & Immunology, Weill Cornell Medical College, New York, NY, 10065
| | - Carl Nathan
- Department of Microbiology & Immunology, Weill Cornell Medical College, New York, NY, 10065
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Abstract
About 2,500 papers dated 2014–2016 were recovered by searching the PubMed database for
Streptomyces, which are the richest known source of antibiotics. This review integrates around 100 of these papers in sections dealing with evolution, ecology, pathogenicity, growth and development, stress responses and secondary metabolism, gene expression, and technical advances. Genomic approaches have greatly accelerated progress. For example, it has been definitively shown that interspecies recombination of conserved genes has occurred during evolution, in addition to exchanges of some of the tens of thousands of non-conserved accessory genes. The closeness of the association of
Streptomyces with plants, fungi, and insects has become clear and is reflected in the importance of regulators of cellulose and chitin utilisation in overall
Streptomyces biology. Interestingly, endogenous cellulose-like glycans are also proving important in hyphal growth and in the clumping that affects industrial fermentations. Nucleotide secondary messengers, including cyclic di-GMP, have been shown to provide key input into developmental processes such as germination and reproductive growth, while late morphological changes during sporulation involve control by phosphorylation. The discovery that nitric oxide is produced endogenously puts a new face on speculative models in which regulatory Wbl proteins (peculiar to actinobacteria) respond to nitric oxide produced in stressful physiological transitions. Some dramatic insights have come from a new model system for
Streptomyces developmental biology,
Streptomyces venezuelae, including molecular evidence of very close interplay in each of two pairs of regulatory proteins. An extra dimension has been added to the many complexities of the regulation of secondary metabolism by findings of regulatory crosstalk within and between pathways, and even between species, mediated by end products. Among many outcomes from the application of chromosome immunoprecipitation sequencing (ChIP-seq) analysis and other methods based on “next-generation sequencing” has been the finding that 21% of
Streptomyces mRNA species lack leader sequences and conventional ribosome binding sites. Further technical advances now emerging should lead to continued acceleration of knowledge, and more effective exploitation, of these astonishing and critically important organisms.
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Affiliation(s)
- Keith F Chater
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
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12
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Mycobacterium tuberculosis Transcription Machinery: Ready To Respond to Host Attacks. J Bacteriol 2016; 198:1360-73. [PMID: 26883824 DOI: 10.1128/jb.00935-15] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Regulating responses to stress is critical for all bacteria, whether they are environmental, commensal, or pathogenic species. For pathogenic bacteria, successful colonization and survival in the host are dependent on adaptation to diverse conditions imposed by the host tissue architecture and the immune response. Once the bacterium senses a hostile environment, it must enact a change in physiology that contributes to the organism's survival strategy. Inappropriate responses have consequences; hence, the execution of the appropriate response is essential for survival of the bacterium in its niche. Stress responses are most often regulated at the level of gene expression and, more specifically, transcription. This minireview focuses on mechanisms of regulating transcription initiation that are required by Mycobacterium tuberculosis to respond to the arsenal of defenses imposed by the host during infection. In particular, we highlight how certain features of M. tuberculosis physiology allow this pathogen to respond swiftly and effectively to host defenses. By enacting highly integrated and coordinated gene expression changes in response to stress,M. tuberculosis is prepared for battle against the host defense and able to persist within the human population.
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13
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Nitrogen oxide cycle regulates nitric oxide levels and bacterial cell signaling. Sci Rep 2016; 6:22038. [PMID: 26912114 PMCID: PMC4766573 DOI: 10.1038/srep22038] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 02/04/2016] [Indexed: 12/28/2022] Open
Abstract
Nitric oxide (NO) signaling controls various metabolic pathways in bacteria and higher eukaryotes. Cellular enzymes synthesize and detoxify NO; however, a mechanism that controls its cellular homeostasis has not been identified. Here, we found a nitrogen oxide cycle involving nitrate reductase (Nar) and the NO dioxygenase flavohemoglobin (Fhb), that facilitate inter-conversion of nitrate, nitrite, and NO in the actinobacterium Streptomyces coelicolor. This cycle regulates cellular NO levels, bacterial antibiotic production, and morphological differentiation. NO down-regulates Nar and up-regulates Fhb gene expression via the NO-dependent transcriptional factors DevSR and NsrR, respectively, which are involved in the auto-regulation mechanism of intracellular NO levels. Nitrite generated by the NO cycles induces gene expression in neighboring cells, indicating an additional role of the cycle as a producer of a transmittable inter-cellular communication molecule.
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Vázquez-Torres A, Bäumler AJ. Nitrate, nitrite and nitric oxide reductases: from the last universal common ancestor to modern bacterial pathogens. Curr Opin Microbiol 2015; 29:1-8. [PMID: 26426528 DOI: 10.1016/j.mib.2015.09.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/01/2015] [Accepted: 09/08/2015] [Indexed: 01/16/2023]
Abstract
The electrochemical gradient that ensues from the enzymatic activity of cytochromes such as nitrate reductase, nitric oxide reductase, and quinol oxidase contributes to the bioenergetics of the bacterial cell. Reduction of nitrogen oxides by bacterial pathogens can, however, be uncoupled from proton translocation and biosynthesis of ATP or NH4(+), but still linked to quinol and NADH oxidation. Ancestral nitric oxide reductases, as well as cytochrome c oxidases and quinol bo oxidases evolved from the former, are capable of binding and detoxifying nitric oxide to nitrous oxide. The NO-metabolizing activity associated with these cytochromes can be a sizable source of antinitrosative defense in bacteria during their associations with host cells. Nitrosylation of terminal cytochromes arrests respiration, reprograms bacterial metabolism, stimulates antioxidant defenses and alters antibiotic cytotoxicity. Collectively, the bioenergetics and regulation of redox homeostasis that accompanies the utilization of nitrogen oxides and detoxification of nitric oxide by cytochromes of the electron transport chain increases fitness of many Gram-positive and -negative pathogens during their associations with invertebrate and vertebrate hosts.
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Affiliation(s)
- Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States; Veterans Affairs Eastern Colorado Health Care System, Denver, CO, United States.
| | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, University of California Davis, School of Medicine, Davis, CA, United States.
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Huang Q, Abdalla AE, Xie J. Phylogenomics of Mycobacterium Nitrate Reductase Operon. Curr Microbiol 2015; 71:121-8. [PMID: 25980349 DOI: 10.1007/s00284-015-0838-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 04/13/2015] [Indexed: 11/24/2022]
Abstract
NarGHJI operon encodes a nitrate reductase that can reduce nitrate to nitrite. This process enhances bacterial survival by nitrate respiration under anaerobic conditions. NarGHJI operon exists in many bacteria, especially saprophytic bacteria living in soil which play a key role in the nitrogen cycle. Most actinomycetes, including Mycobacterium tuberculosis, possess NarGHJI operons. M. tuberculosis is a facultative intracellular pathogen that expands in macrophages and has the ability to persist in a non-replicative form in granuloma lifelong. Nitrogen and nitrogen compounds play crucial roles in the struggle between M. tuberculosis and host. M. tuberculosis can use nitrate as a final electron acceptor under anaerobic conditions to enhance its survival. In this article, we reviewed the mechanisms regulating nitrate reductase expression and affecting its activity. Potential genes involved in regulating the nitrate reductase expression in M. tuberculosis were identified. The conserved NarG might be an alternative mycobacterium taxonomic marker.
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Affiliation(s)
- Qinqin Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, 1 Rd Tiansheng, Beibei, Chongqing, 400715, People's Republic of China
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Mendum TA, Wu H, Kierzek AM, Stewart GR. Lipid metabolism and Type VII secretion systems dominate the genome scale virulence profile of Mycobacterium tuberculosis in human dendritic cells. BMC Genomics 2015; 16:372. [PMID: 25956932 PMCID: PMC4425887 DOI: 10.1186/s12864-015-1569-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 04/23/2015] [Indexed: 12/20/2022] Open
Abstract
Background Mycobacterium tuberculosis continues to kill more people than any other bacterium. Although its archetypal host cell is the macrophage, it also enters, and survives within, dendritic cells (DCs). By modulating the behaviour of the DC, M. tuberculosis is able to manipulate the host’s immune response and establish an infection. To identify the M. tuberculosis genes required for survival within DCs we infected primary human DCs with an M. tuberculosis transposon library and identified mutations with a reduced ability to survive. Results Parallel sequencing of the transposon inserts of the surviving mutants identified a large number of genes as being required for optimal intracellular fitness in DCs. Loci whose mutation attenuated intracellular survival included those involved in synthesising cell wall lipids, not only the well-established virulence factors, pDIM and cord factor, but also sulfolipids and PGL, which have not previously been identified as having a direct virulence role in cells. Other attenuated loci included the secretion systems ESX-1, ESX-2 and ESX-4, alongside many PPE genes, implicating a role for ESX-5. In contrast the canonical ESAT-6 family of ESX substrates did not have intra-DC fitness costs suggesting an alternative ESX-1 associated virulence mechanism. With the aid of a gene-nutrient interaction model, metabolic processes such as cholesterol side chain catabolism, nitrate reductase and cysteine-methionine metabolism were also identified as important for survival in DCs. Conclusion We conclude that many of the virulence factors required for survival in DC are shared with macrophages, but that survival in DCs also requires several additional functions, such as cysteine-methionine metabolism, PGLs, sulfolipids, ESX systems and PPE genes. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1569-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tom A Mendum
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
| | - Huihai Wu
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
| | - Andrzej M Kierzek
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
| | - Graham R Stewart
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
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Fischer M, Falke D, Pawlik T, Sawers RG. Oxygen-dependent control of respiratory nitrate reduction in mycelium of Streptomyces coelicolor A3(2). J Bacteriol 2014; 196:4152-62. [PMID: 25225271 PMCID: PMC4248870 DOI: 10.1128/jb.02202-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 09/09/2014] [Indexed: 01/28/2023] Open
Abstract
Several members of the obligately aerobic genus Streptomyces are able to reduce nitrate, catalyzed by Nar-type respiratory nitrate reductases. A unique feature of Streptomyces coelicolor A3(2) compared with other streptomycetes is that it synthesizes three nonredundant Nar enzymes. In this study, we show that Nar2 is the main Nar enzyme active in mycelium and could characterize the conditions governing its synthesis. Nar2 was present at low levels in aerobically cultivated mycelium, but synthesis was induced when cultures were grown under oxygen limitation. Growth in the presence of high oxygen concentrations prevented the induction of Nar2 synthesis. Equally, an abrupt shift from aerobiosis to anaerobiosis did not result in the immediate induction of Nar2 synthesis. This suggests that the synthesis of Nar2 is induced during a hypoxic downshift, probably to allow maintenance of a proton gradient during the transition to anaerobiosis. Although no Nar2 could be detected in freshly harvested mature spores, synthesis of the enzyme could be induced after long-term (several days) incubation of these resting spores under anaerobic conditions. Induction of Nar2 synthesis in spores was linked to transcriptional control. Nar2 activity in whole mycelium was strictly dependent on the presence of a putative nitrate transporter, NarK2. The oxygen-dependent inhibition of nitrate reduction by Nar2 was mediated by NarK2-dependent nitrate:nitrite antiport. This antiport mechanism likely prevents the accumulation of toxic nitrite in the cytoplasm. A deletion of the narK2 gene had no effect on Nar1-dependent nitrate reduction in resting spores. Together, our results indicate redox-dependent transcriptional and posttranslational control of nitrate reduction by Nar2.
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Affiliation(s)
- Marco Fischer
- Institute of Biology/Microbiology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Dörte Falke
- Institute of Biology/Microbiology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Tony Pawlik
- Institute of Biology/Microbiology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - R Gary Sawers
- Institute of Biology/Microbiology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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bis-Molybdopterin guanine dinucleotide is required for persistence of Mycobacterium tuberculosis in guinea pigs. Infect Immun 2014; 83:544-50. [PMID: 25404027 DOI: 10.1128/iai.02722-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mycobacterium tuberculosis is able to synthesize molybdopterin cofactor (MoCo), which is utilized by numerous enzymes that catalyze redox reactions in carbon, nitrogen, and sulfur metabolism. In bacteria, MoCo is further modified through the activity of a guanylyltransferase, MobA, which converts MoCo to bis-molybdopterin guanine dinucleotide (bis-MGD), a form of the cofactor that is required by the dimethylsulfoxide (DMSO) reductase family of enzymes, which includes the nitrate reductase NarGHI. In this study, the functionality of the mobA homolog in M. tuberculosis was confirmed by demonstrating the loss of assimilatory and respiratory nitrate reductase activity in a mobA deletion mutant. This mutant displayed no survival defects in human monocytes or mouse lungs but failed to persist in the lungs of guinea pigs. These results implicate one or more bis-MGD-dependent enzymes in the persistence of M. tuberculosis in guinea pig lungs and underscore the applicability of this animal model for assessing the role of molybdoenzymes in this pathogen.
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Cunningham-Bussel A, Zhang T, Nathan CF. Nitrite produced by Mycobacterium tuberculosis in human macrophages in physiologic oxygen impacts bacterial ATP consumption and gene expression. Proc Natl Acad Sci U S A 2013; 110:E4256-65. [PMID: 24145454 PMCID: PMC3831502 DOI: 10.1073/pnas.1316894110] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In high enough concentrations, such as produced by inducible nitric oxide synthase (iNOS), reactive nitrogen species (RNS) can kill Mycobacterium tuberculosis (Mtb). Lesional macrophages in macaques and humans with tuberculosis express iNOS, and mice need iNOS to avoid succumbing rapidly to tuberculosis. However, Mtb's own ability to produce RNS is rarely considered, perhaps because nitrate reduction to nitrite is only prominent in axenic Mtb cultures at oxygen tensions ≤1%. Here we found that cultures of Mtb-infected human macrophages cultured at physiologic oxygen tensions produced copious nitrite. Surprisingly, the nitrite arose from the Mtb, not the macrophages. Mtb responded to nitrite by ceasing growth; elevating levels of ATP through reduced consumption; and altering the expression of 120 genes associated with adaptation to acid, hypoxia, nitric oxide, oxidative stress, and iron deprivation. The transcriptomic effect of endogenous nitrite was distinct from that of nitric oxide. Thus, whether or not Mtb is hypoxic, the host expresses iNOS, or hypoxia impairs the action of iNOS, Mtb in vivo is likely to encounter RNS by producing nitrite. Endogenous nitrite may slow Mtb's growth and prepare it to resist host stresses while the pathogen waits for immunopathology to promote its transmission.
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Affiliation(s)
| | - Tuo Zhang
- Department of Microbiology and Immunology and
- Genomics Resources Core Facility, Weill Cornell Medical College, New York, NY 10065
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