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Słabońska J, Sappati S, Marciniak A, Czub J. Low-Barrier Hydrogen Bond Determines Target-Binding Affinity and Specificity of the Antitubercular Drug Bedaquiline. ACS Med Chem Lett 2024; 15:265-269. [PMID: 38352844 PMCID: PMC10860170 DOI: 10.1021/acsmedchemlett.3c00509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/16/2023] [Accepted: 12/19/2023] [Indexed: 02/16/2024] Open
Abstract
The role of short strong hydrogen bonds (SSHBs) in ligand-target binding remains largely unexplored, thereby hindering a potentially important avenue in rational drug design. Here we investigate the interaction between the antituberculosis drug bedaquiline (Bq) and the mycobacterial ATP synthase to unravel the role of a specific hydrogen bond to a conserved acidic residue in the target affinity and specificity. Our ab initio molecular dynamics simulations reveal that this bond belongs to the SSHB category and accounts for a substantial fraction of the target binding free energy. We also demonstrate that the presence of an extra acidic residue, i.e., aspartic acid at position 32 (D32), found exclusively in mycobacteria, cooperatively enhances the HB strength, ensuring specificity for the mycobacterial target. Consistently, we show that the removal of D32 markedly weakens the affinity, leading to Bq resistance associated with mutations of D32 to nonacidic residues. By designing simple Bq analogs, we then explore the possibility to overcome the resistance and potentially broaden the Bq antimicrobial spectrum by making the SSHB independent of the presence of the extra acidic residue.
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Affiliation(s)
- Joanna Słabońska
- Department
of Physical Chemistry, Gdańsk University
of Technology, Narutowicza St 11/12, Gdańsk 80-233, Poland
| | - Subrahmanyam Sappati
- Department
of Physical Chemistry, Gdańsk University
of Technology, Narutowicza St 11/12, Gdańsk 80-233, Poland
- BioTechMed
Center, Gdańsk University of Technology, Narutowicza St 11/12, Gdańsk 80-233, Poland
| | - Antoni Marciniak
- Department
of Physical Chemistry, Gdańsk University
of Technology, Narutowicza St 11/12, Gdańsk 80-233, Poland
- Department
of Applied Physics, KTH Royal Institute
of Technology, SE-171 65 Solna, Sweden
| | - Jacek Czub
- Department
of Physical Chemistry, Gdańsk University
of Technology, Narutowicza St 11/12, Gdańsk 80-233, Poland
- BioTechMed
Center, Gdańsk University of Technology, Narutowicza St 11/12, Gdańsk 80-233, Poland
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2
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Ragunathan P, Shuyi Ng P, Singh S, Poh WH, Litty D, Kalia NP, Larsson S, Harikishore A, Rice SA, Ingham PW, Müller V, Moraski G, Miller MJ, Dick T, Pethe K, Grüber G. GaMF1.39's antibiotic efficacy and its enhanced antitubercular activity in combination with clofazimine, Telacebec, ND-011992, or TBAJ-876. Microbiol Spectr 2023; 11:e0228223. [PMID: 37982630 PMCID: PMC10715162 DOI: 10.1128/spectrum.02282-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 10/12/2023] [Indexed: 11/21/2023] Open
Abstract
IMPORTANCE New drugs are needed to combat multidrug-resistant tuberculosis. The electron transport chain (ETC) maintains the electrochemical potential across the cytoplasmic membrane and allows the production of ATP, the energy currency of any living cell. The mycobacterial engine F-ATP synthase catalyzes the formation of ATP and has come into focus as an attractive and rich drug target. Recent deep insights into these mycobacterial F1FO-ATP synthase elements opened the door for a renaissance of structure-based target identification and inhibitor design. In this study, we present the GaMF1.39 antimycobacterial compound, targeting the rotary subunit γ of the biological engine. The compound is bactericidal, inhibits infection ex vivo, and displays enhanced anti-tuberculosis activity in combination with ETC inhibitors, which promises new strategies to shorten tuberculosis chemotherapy.
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Affiliation(s)
- Priya Ragunathan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Pearly Shuyi Ng
- Experimental Drug Development Centre, Agency for Science, Technology and Research, Singapore, Singapore
| | - Samsher Singh
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Singapore, Singapore
| | - Wee Han Poh
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Dennis Litty
- Molecular Microbiology and Bioenergetics, Institute for Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, Frankfurt, Germany
| | - Nitin Pal Kalia
- Department of Biological Sciences (Pharmacology & Toxicology), National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
| | - Simon Larsson
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Singapore, Singapore
| | - Amaravadhi Harikishore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore
| | - Scott A. Rice
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Philip W. Ingham
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Singapore, Singapore
| | - Volker Müller
- Molecular Microbiology and Bioenergetics, Institute for Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, Frankfurt, Germany
| | - Garrett Moraski
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Marvin J. Miller
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Thomas Dick
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
- Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, New Jersey, USA
- Department of Microbiology and Immunology, Georgetown University, Washington, DC, USA
| | - Kevin Pethe
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Singapore, Singapore
- National Centre for Infectious Diseases (NCID), Jalan Tan Tock Seng, Singapore, Singapore
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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3
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Butler MS, Henderson IR, Capon RJ, Blaskovich MAT. Antibiotics in the clinical pipeline as of December 2022. J Antibiot (Tokyo) 2023; 76:431-473. [PMID: 37291465 PMCID: PMC10248350 DOI: 10.1038/s41429-023-00629-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 06/10/2023]
Abstract
The need for new antibacterial drugs to treat the increasing global prevalence of drug-resistant bacterial infections has clearly attracted global attention, with a range of existing and upcoming funding, policy, and legislative initiatives designed to revive antibacterial R&D. It is essential to assess whether these programs are having any real-world impact and this review continues our systematic analyses that began in 2011. Direct-acting antibacterials (47), non-traditional small molecule antibacterials (5), and β-lactam/β-lactamase inhibitor combinations (10) under clinical development as of December 2022 are described, as are the three antibacterial drugs launched since 2020. Encouragingly, the increased number of early-stage clinical candidates observed in the 2019 review increased in 2022, although the number of first-time drug approvals from 2020 to 2022 was disappointingly low. It will be critical to monitor how many Phase-I and -II candidates move into Phase-III and beyond in the next few years. There was also an enhanced presence of novel antibacterial pharmacophores in early-stage trials, and at least 18 of the 26 phase-I candidates were targeted to treat Gram-negative bacteria infections. Despite the promising early-stage antibacterial pipeline, it is essential to maintain funding for antibacterial R&D and to ensure that plans to address late-stage pipeline issues succeed.
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Affiliation(s)
- Mark S Butler
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Brisbane, 4072, Australia.
| | - Ian R Henderson
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Brisbane, 4072, Australia
| | - Robert J Capon
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Brisbane, 4072, Australia
| | - Mark A T Blaskovich
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Brisbane, 4072, Australia.
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4
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Courbon GM, Palme PR, Mann L, Richter A, Imming P, Rubinstein JL. Mechanism of mycobacterial ATP synthase inhibition by squaramides and second generation diarylquinolines. EMBO J 2023; 42:e113687. [PMID: 37377118 PMCID: PMC10390873 DOI: 10.15252/embj.2023113687] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/03/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Mycobacteria, such as Mycobacterium tuberculosis, depend on the activity of adenosine triphosphate (ATP) synthase for growth. The diarylquinoline bedaquiline (BDQ), a mycobacterial ATP synthase inhibitor, is an important medication for treatment of drug-resistant tuberculosis but suffers from off-target effects and is susceptible to resistance mutations. Consequently, both new and improved mycobacterial ATP synthase inhibitors are needed. We used electron cryomicroscopy and biochemical assays to study the interaction of Mycobacterium smegmatis ATP synthase with the second generation diarylquinoline TBAJ-876 and the squaramide inhibitor SQ31f. The aryl groups of TBAJ-876 improve binding compared with BDQ, while SQ31f, which blocks ATP synthesis ~10 times more potently than ATP hydrolysis, binds a previously unknown site in the enzyme's proton-conducting channel. Remarkably, BDQ, TBAJ-876, and SQ31f all induce similar conformational changes in ATP synthase, suggesting that the resulting conformation is particularly suited for drug binding. Further, high concentrations of the diarylquinolines uncouple the transmembrane proton motive force while for SQ31f they do not, which may explain why high concentrations of diarylquinolines, but not SQ31f, have been reported to kill mycobacteria.
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Affiliation(s)
- Gautier M Courbon
- Molecular Medicine ProgramThe Hospital for Sick ChildrenTorontoONCanada
- Department of Medical BiophysicsThe University of TorontoTorontoONCanada
| | - Paul R Palme
- Institut für PharmazieMartin‐Luther‐Universität Halle‐WittenbergHalle, SaaleGermany
| | - Lea Mann
- Institut für PharmazieMartin‐Luther‐Universität Halle‐WittenbergHalle, SaaleGermany
| | - Adrian Richter
- Institut für PharmazieMartin‐Luther‐Universität Halle‐WittenbergHalle, SaaleGermany
| | - Peter Imming
- Institut für PharmazieMartin‐Luther‐Universität Halle‐WittenbergHalle, SaaleGermany
| | - John L Rubinstein
- Molecular Medicine ProgramThe Hospital for Sick ChildrenTorontoONCanada
- Department of Medical BiophysicsThe University of TorontoTorontoONCanada
- Department of BiochemistryThe University of TorontoTorontoONCanada
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5
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Chen J, Ekiert DC. A tale of two inhibitors: diarylquinolines and squaramides. EMBO J 2023; 42:e114912. [PMID: 37435707 PMCID: PMC10390866 DOI: 10.15252/embj.2023114912] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/13/2023] Open
Abstract
The diarylquinoline bedaquiline (BDQ) is an FDA-approved drug for the treatment of multidrug-resistant tuberculosis that targets the mycobacterial adenosine triphosphate (ATP) synthase, a key enzyme in cellular respiration. In a recent study, Courbon et al (2023) examine the interaction between Mycobacterium smegmatis ATP synthase with the second generation diarylquinoline TBAJ-876 and the squaramide inhibitor SQ31f, showing that both drugs prevent the rotatory motions needed for enzymatic function.
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Affiliation(s)
- James Chen
- Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
- Department of MicrobiologyNYU School of MedicineNew YorkNYUSA
| | - Damian C Ekiert
- Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
- Department of MicrobiologyNYU School of MedicineNew YorkNYUSA
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6
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F1·Fo ATP Synthase/ATPase: Contemporary View on Unidirectional Catalysis. Int J Mol Sci 2023; 24:ijms24065417. [PMID: 36982498 PMCID: PMC10049701 DOI: 10.3390/ijms24065417] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 03/05/2023] [Accepted: 03/10/2023] [Indexed: 03/14/2023] Open
Abstract
F1·Fo-ATP synthases/ATPases (F1·Fo) are molecular machines that couple either ATP synthesis from ADP and phosphate or ATP hydrolysis to the consumption or production of a transmembrane electrochemical gradient of protons. Currently, in view of the spread of drug-resistant disease-causing strains, there is an increasing interest in F1·Fo as new targets for antimicrobial drugs, in particular, anti-tuberculosis drugs, and inhibitors of these membrane proteins are being considered in this capacity. However, the specific drug search is hampered by the complex mechanism of regulation of F1·Fo in bacteria, in particular, in mycobacteria: the enzyme efficiently synthesizes ATP, but is not capable of ATP hydrolysis. In this review, we consider the current state of the problem of “unidirectional” F1·Fo catalysis found in a wide range of bacterial F1·Fo and enzymes from other organisms, the understanding of which will be useful for developing a strategy for the search for new drugs that selectively disrupt the energy production of bacterial cells.
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7
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Edwards BD, Field SK. The Struggle to End a Millennia-Long Pandemic: Novel Candidate and Repurposed Drugs for the Treatment of Tuberculosis. Drugs 2022; 82:1695-1715. [PMID: 36479687 PMCID: PMC9734533 DOI: 10.1007/s40265-022-01817-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2022] [Indexed: 12/12/2022]
Abstract
This article provides an encompassing review of the current pipeline of putative and developed treatments for tuberculosis, including multidrug-resistant strains. The review has organized each compound according to its site of activity. To provide context, mention of drugs within current recommended treatment regimens is made, thereafter followed by discussion on recently developed and upcoming molecules at established and novel targets. The review is designed to provide a clinically applicable understanding of the compounds that are deemed most currently relevant, including those already under clinical study and those that have shown promising pre-clinical results. An extensive review of the efficacy and safety data for key contemporary drugs already incorporated into treatment regimens, such as bedaquiline, pretomanid, and linezolid, is provided. The three levels of the bacterial cell wall (mycolic acid, arabinogalactan, and peptidoglycan layers) are highlighted and important compounds designed to target each layer are delineated. Amongst others, the highly optimistic and potent anti-mycobacterial activity of agents such as BTZ-043, PBTZ 169, and OPC-167832 are emphasized. The evolving spectrum of oxazolidinones, such as sutezolid, delpazolid, and TBI-223, all aiming to exceed the efficacy achieved with linezolid yet offer a safer alternative to the potential toxicity, are reviewed. New and exciting prospective agents with novel mechanisms of impact against TB, including 3-aminomethyl benzoxaboroles and telacebec, are underscored. We describe new diaryloquinolines in development, striving to build on the immense success of bedaquiline. Finally, we discuss some of these compounds that have shown encouraging additive or synergistic benefit when used in combination, providing some promise for the future in treating this ancient scourge.
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Affiliation(s)
- Brett D Edwards
- Division of Infectious Diseases and Tuberculosis Services, Alberta Health Services, Department of Medicine, Cumming School of Medicine, University of Calgary, Peter Lougheed Centre, 3500, 26 Avenue NE, Calgary, AB, T1Y6J4, Canada.
| | - Stephen K Field
- Division of Infectious Diseases and Tuberculosis Services, Alberta Health Services, Department of Medicine, Cumming School of Medicine, University of Calgary, Peter Lougheed Centre, 3500, 26 Avenue NE, Calgary, AB, T1Y6J4, Canada
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8
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Why Matter Matters: Fast-Tracking Mycobacterium abscessus Drug Discovery. Molecules 2022; 27:molecules27206948. [PMID: 36296540 PMCID: PMC9608607 DOI: 10.3390/molecules27206948] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/17/2022] Open
Abstract
Unlike Tuberculosis (TB), Mycobacterium abscessus lung disease is a highly drug-resistant bacterial infection with no reliable treatment options. De novo M. abscessus drug discovery is urgently needed but is hampered by the bacterium's extreme drug resistance profile, leaving the current drug pipeline underpopulated. One proposed strategy to accelerate de novo M. abscessus drug discovery is to prioritize screening of advanced TB-active compounds for anti-M. abscessus activity. This approach would take advantage of the greater chance of homologous drug targets between mycobacterial species, increasing hit rates. Furthermore, the screening of compound series with established structure-activity-relationship, pharmacokinetic, and tolerability properties should fast-track the development of in vitro anti-M. abscessus hits into lead compounds with in vivo efficacy. In this review, we evaluated the effectiveness of this strategy by examining the literature. We found several examples where the screening of advanced TB chemical matter resulted in the identification of anti-M. abscessus compounds with in vivo proof-of-concept, effectively populating the M. abscessus drug pipeline with promising new candidates. These reports validate the screening of advanced TB chemical matter as an effective means of fast-tracking M. abscessus drug discovery.
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9
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Fernandes GFS, Thompson AM, Castagnolo D, Denny WA, Dos Santos JL. Tuberculosis Drug Discovery: Challenges and New Horizons. J Med Chem 2022; 65:7489-7531. [PMID: 35612311 DOI: 10.1021/acs.jmedchem.2c00227] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Over the past 2000 years, tuberculosis (TB) has claimed more lives than any other infectious disease. In 2020 alone, TB was responsible for 1.5 million deaths worldwide, comparable to the 1.8 million deaths caused by COVID-19. The World Health Organization has stated that new TB drugs must be developed to end this pandemic. After decades of neglect in this field, a renaissance era of TB drug discovery has arrived, in which many novel candidates have entered clinical trials. However, while hundreds of molecules are reported annually as promising anti-TB agents, very few successfully progress to clinical development. In this Perspective, we critically review those anti-TB compounds published in the last 6 years that demonstrate good in vivo efficacy against Mycobacterium tuberculosis. Additionally, we highlight the main challenges and strategies for developing new TB drugs and the current global pipeline of drug candidates in clinical studies to foment fresh research perspectives.
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Affiliation(s)
- Guilherme F S Fernandes
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Andrew M Thompson
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Daniele Castagnolo
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - William A Denny
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Jean L Dos Santos
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara 14800903, Brazil
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10
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Santucci P, Aylan B, Botella L, Bernard EM, Bussi C, Pellegrino E, Athanasiadi N, Gutierrez MG. Visualizing Pyrazinamide Action by Live Single-Cell Imaging of Phagosome Acidification and Mycobacterium tuberculosis pH Homeostasis. mBio 2022; 13:e0011722. [PMID: 35323041 PMCID: PMC9040869 DOI: 10.1128/mbio.00117-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/24/2022] [Indexed: 01/28/2023] Open
Abstract
Mycobacterium tuberculosis segregates within multiple subcellular niches with different biochemical and biophysical properties that, upon treatment, may impact antibiotic distribution, accumulation, and efficacy. However, it remains unclear whether fluctuating intracellular microenvironments alter mycobacterial homeostasis and contribute to antibiotic enrichment and efficacy. Here, we describe a live dual-imaging approach to monitor host subcellular acidification and M. tuberculosis intrabacterial pH. By combining this approach with pharmacological and genetic perturbations, we show that M. tuberculosis can maintain its intracellular pH independently of the surrounding pH in human macrophages. Importantly, unlike bedaquiline (BDQ), isoniazid (INH), or rifampicin (RIF), the drug pyrazinamide (PZA) displays antibacterial efficacy by disrupting M. tuberculosis intrabacterial pH homeostasis in cellulo. By using M. tuberculosis mutants, we confirmed that intracellular acidification is a prerequisite for PZA efficacy in cellulo. We anticipate this imaging approach will be useful to identify host cellular environments that affect antibiotic efficacy against intracellular pathogens. IMPORTANCE We still do not completely understand why tuberculosis (TB) treatment requires the combination of several antibiotics for up to 6 months. M. tuberculosis is a facultative intracellular pathogen, and it is still unknown whether heterogenous and dynamic intracellular populations of bacteria in different cellular environments affect antibiotic efficacy. By developing a dual live imaging approach to monitor mycobacterial pH homeostasis, host cell environment, and antibiotic action, we show here that intracellular localization of M. tuberculosis affects the efficacy of one first-line anti-TB drug. Our observations can be applicable to the treatment of other intracellular pathogens and help to inform the development of more effective combined therapies for tuberculosis that target heterogenous bacterial populations within the host.
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Affiliation(s)
- Pierre Santucci
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Beren Aylan
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Laure Botella
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Elliott M. Bernard
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Claudio Bussi
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Enrica Pellegrino
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Natalia Athanasiadi
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Maximiliano G. Gutierrez
- Host-Pathogen Interactions in Tuberculosis Laboratory, The Francis Crick Institute, London, United Kingdom
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11
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Krah A, Grüber G, Bond PJ. Binding properties of the anti-TB drugs bedaquiline and TBAJ-876 to a mycobacterial F-ATP synthase. Curr Res Struct Biol 2022; 4:278-284. [PMID: 36186842 PMCID: PMC9516385 DOI: 10.1016/j.crstbi.2022.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 08/13/2022] [Accepted: 09/08/2022] [Indexed: 11/30/2022] Open
Abstract
Tuberculosis (TB), the deadly disease caused by Mycobacterium tuberculosis (Mtb), kills more people worldwide than any other bacterial infectious disease. There has been a recent resurgence of TB drug discovery activities, resulting in the identification of a number of novel enzyme inhibitors. Many of these inhibitors target the electron transport chain complexes and the F1FO-ATP synthase; these enzymes represent new target spaces for drug discovery, since the generation of ATP is essential for the bacterial pathogen's physiology, persistence, and pathogenicity. The anti-TB drug bedaquiline (BDQ) targets the Mtb F-ATP synthase and is used as salvage therapy against this disease. Medicinal chemistry efforts to improve the physio-chemical properties of BDQ resulted in the discovery of 3,5-dialkoxypyridine (DARQ) analogs to which TBAJ-876 belongs. TBAJ-876, a clinical development candidate, shows attractive in vitro and in vivo antitubercular activity. Both BDQ and TBAJ-876 inhibit the mycobacterial F1FO-ATP synthase by stopping rotation of the c-ring turbine within the FO domain, thereby preventing proton translocation and ATP synthesis to occur. While structural data for the BDQ bound state are available, no structural information about TBAJ-876 binding have been described. In this study, we show how TBAJ-876 binds to the FO domain of the M. smegmatis F1FO-ATP synthase. We further calculate the binding free energy of both drugs bound to their target and predict an increased affinity of TBAJ-876 for the FO domain. This approach will be useful in future efforts to design new and highly potent DARQ analogs targeting F-ATP synthases of Mtb, nontuberculosis mycobacteria (NTM) as well as the M. leprosis complex. BDQ inhibits mycobacterial F-ATP synthase. TBAJ-876 is a BDQ analogue with improved affinity for the enzyme. Simulations help to structurally clarify the FO domain binding sites of TBAJ-876. Insights will help guide development of multidrug-resistant tuberculosis drugs.
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Affiliation(s)
- Alexander Krah
- Bioinformatics Institute, Agency for Science, Technology and Research (A∗STAR), 30 Biopolis Str., #07-01 Matrix, 138671, Singapore
- Corresponding author.
| | - Gerhard Grüber
- Bioinformatics Institute, Agency for Science, Technology and Research (A∗STAR), 30 Biopolis Str., #07-01 Matrix, 138671, Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Peter J. Bond
- Bioinformatics Institute, Agency for Science, Technology and Research (A∗STAR), 30 Biopolis Str., #07-01 Matrix, 138671, Singapore
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore
- Corresponding author. Bioinformatics Institute, Agency for Science, Technology and Research (A∗STAR), 30 Biopolis Str., #07-01 Matrix, 138671, Singapore.
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12
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The antimicrobial and immunomodulatory effects of Ionophores for the treatment of human infection. J Inorg Biochem 2021; 227:111661. [PMID: 34896767 DOI: 10.1016/j.jinorgbio.2021.111661] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/27/2021] [Accepted: 11/03/2021] [Indexed: 12/18/2022]
Abstract
Ionophores are a diverse class of synthetic and naturally occurring ion transporter compounds which demonstrate both direct and in-direct antimicrobial properties against a broad panel of bacterial, fungal, viral and parasitic pathogens. In addition, ionophores can regulate the host-immune response during communicable and non-communicable disease states. Although the clinical use of ionophores such as Amphotericin B, Bedaquiline and Ivermectin highlight the utility of ionophores in modern medicine, for many other ionophore compounds issues surrounding toxicity, bioavailability or lack of in vivo efficacy studies have hindered clinical development. The antimicrobial and immunomodulating properties of a range of compounds with characteristics of ionophores remain largely unexplored. As such, ionophores remain a latent therapeutic avenue to address both the global burden of antimicrobial resistance, and the unmet clinical need for new antimicrobial therapies. This review will provide an overview of the broad-spectrum antimicrobial and immunomodulatory properties of ionophores, and their potential uses in clinical medicine for combatting infection.
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13
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Barbaro L, Nagalingam G, Triccas JA, Tan L, West NP, Baell JB, Priebbenow DL. Synthesis and evaluation of pyridine-derived bedaquiline analogues containing modifications at the A-ring subunit. RSC Med Chem 2021; 12:943-959. [PMID: 34223160 DOI: 10.1039/d1md00063b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/22/2021] [Indexed: 11/21/2022] Open
Abstract
Despite promising efficacy, the clinical use of the anti-tubercular therapeutic bedaquiline has been restricted due to safety concerns. To date, limited SAR studies have focused on the quinoline ring (A-ring), and as such, we set out to explore modifications within this region in an attempt to discover new bedaquiline variants with an improved safety profile. We herein report the development of unique synthetic strategies that facilitated access to novel bedaquiline analogues leading to the discovery that anti-tubercular activity could be retained following replacement of the quinoline motif with pyridine heterocycles. This discovery is anticipated to open up multiple new avenues for exploration in the design of improved anti-tubercular therapeutics.
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Affiliation(s)
- Lisa Barbaro
- Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Gayathri Nagalingam
- School of Medical Sciences and Marie Bashir Institute, The University of Sydney Sydney NSW 2006 Australia
| | - James A Triccas
- School of Medical Sciences and Marie Bashir Institute, The University of Sydney Sydney NSW 2006 Australia
| | - Lendl Tan
- School of Chemistry and Molecular Bioscience, The University of Queensland St Lucia Queensland 4072 Australia.,Australian Infectious Diseases Research Centre St. Lucia Queensland 4067 Australia
| | - Nicholas P West
- School of Chemistry and Molecular Bioscience, The University of Queensland St Lucia Queensland 4072 Australia.,Australian Infectious Diseases Research Centre St. Lucia Queensland 4067 Australia
| | - Jonathan B Baell
- Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Daniel L Priebbenow
- School of Chemistry, The University of Melbourne Parkville Victoria 3010 Australia
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14
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Inhibitors of F 1F 0-ATP synthase enzymes for the treatment of tuberculosis and cancer. Future Med Chem 2021; 13:911-926. [PMID: 33845594 DOI: 10.4155/fmc-2021-0010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The spectacular success of the mycobacterial F1F0-ATP synthase inhibitor bedaquiline for the treatment of drug-resistant tuberculosis has generated wide interest in the development of other inhibitors of this enzyme. Work in this realm has included close analogues of bedaquiline with better safety profiles and 'bedaquiline-like' compounds, some of which show potent antibacterial activity in vitro although none have yet progressed to clinical trials. The search has lately extended to a range of new scaffolds as potential inhibitors, including squaramides, diaminoquinazolines, chloroquinolines, dihydropyrazolo[1,5-a]pyrazin-4-ones, thiazolidinediones, diaminopyrimidines and tetrahydroquinolines. Because of the ubiquitous expression of ATP synthase enzymes, there has also been interest in inhibitors of other bacterial ATP synthases, as well as inhibitors of human mitochondrial ATP synthase for cancer therapy. The latter encompass both complex natural products and simpler small molecules. The review seeks to demonstrate the breadth of the structural types of molecules able to effectively inhibit the function of variants of this intriguing enzyme.
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15
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Chauhan A, Kumar M, Kumar A, Kanchan K. Comprehensive review on mechanism of action, resistance and evolution of antimycobacterial drugs. Life Sci 2021; 274:119301. [PMID: 33675895 DOI: 10.1016/j.lfs.2021.119301] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/14/2021] [Accepted: 02/24/2021] [Indexed: 01/04/2023]
Abstract
Tuberculosis is one of the deadliest infectious diseases existing in the world since ancient times and still possesses serious threat across the globe. Each year the number of cases increases due to high drug resistance shown by Mycobacterium tuberculosis (Mtb). Available antimycobacterial drugs have been classified as First line, Second line and Third line antibiotics depending on the time of their discoveries and their effectiveness in the treatment. These antibiotics have a broad range of targets ranging from cell wall to metabolic processes and their non-judicious and uncontrolled usage in the treatment for years has created a significant problem called multi-drug resistant (MDR) tuberculosis. In this review, we have summarized the mechanism of action of all the classified antibiotics currently in use along with the resistance mechanisms acquired by Mtb. We have focused on the new drug candidates/repurposed drugs, and drug in combinations, which are in clinical trials for either treating the MDR tuberculosis more effectively or involved in reducing the time required for the chemotherapy of drug sensitive TB. This information is not discussed very adequately on a single platform. Additionally, we have discussed the recent technologies that are being used to discover novel resistance mechanisms acquired by Mtb and for exploring novel drugs. The story of intrinsic resistance mechanisms and evolution in Mtb is far from complete. Therefore, we have also discussed intrinsic resistance mechanisms of Mtb and their evolution with time, emphasizing the hope for the development of novel antimycobacterial drugs for effective therapy of tuberculosis.
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Affiliation(s)
- Aditi Chauhan
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University Uttar Pradesh, Noida 201313, India
| | - Manoj Kumar
- Amity Food and Agriculture Foundation, Amity University Uttar Pradesh, Noida 201313, India
| | - Awanish Kumar
- Department of Bio Technology, National Institute of Technology, Raipur, India
| | - Kajal Kanchan
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University Uttar Pradesh, Noida 201313, India.
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16
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Chen BC, Ding ZS, Dai JS, Chen NP, Gong XW, Ma LF, Qian CD. New Insights Into the Antibacterial Mechanism of Cryptotanshinone, a Representative Diterpenoid Quinone From Salvia miltiorrhiza Bunge. Front Microbiol 2021; 12:647289. [PMID: 33717044 PMCID: PMC7950322 DOI: 10.3389/fmicb.2021.647289] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/08/2021] [Indexed: 11/16/2022] Open
Abstract
The rapid rise of antibiotic resistance causes an urgent need for new antimicrobial agents with unique and different mechanisms of action. The respiratory chain is one such target involved in the redox balance and energy metabolism. As a natural quinone compound isolated from the root of Salvia miltiorrhiza Bunge, cryptotanshinone (CT) has been previously demonstrated against a wide range of Gram-positive bacteria including multidrug-resistant pathogens. Although superoxide radicals induced by CT are proposed to play an important role in the antibacterial effect of this agent, its mechanism of action is still unclear. In this study, we have shown that CT is a bacteriostatic agent rather than a bactericidal agent. Metabolome analysis suggested that CT might act as an antibacterial agent targeting the cell membrane. CT did not cause severe damage to the bacterial membrane but rapidly dissipated membrane potential, implying that this compound could be a respiratory chain inhibitor. Oxygen consumption analysis in staphylococcal membrane vesicles implied that CT acted as respiratory chain inhibitor probably by targeting type II NADH:quinone dehydrogenase (NDH-2). Molecular docking study suggested that the compound would competitively inhibit the binding of quinone to NDH-2. Consistent with the hypothesis, the antimicrobial activity of CT was blocked by menaquinone, and the combination of CT with thioridazine but not 2-n-heptyl-4-hydroxyquinoline-N-oxide exerted synergistic activity against Staphylococcus aureus. Additionally, combinations of CT with other inhibitors targeting different components of the bacterial respiratory chain exhibit potent synergistic activities against S. aureus, suggesting a promising role in combination therapies.
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Affiliation(s)
- Bo-Chen Chen
- College of Life Science, Institute of Molecular Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhi-Shan Ding
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jian-Sheng Dai
- College of Life Science, Institute of Molecular Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Ni-Pi Chen
- College of Life Science, Institute of Molecular Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xing-Wen Gong
- Department of Biological Engineering, Zhejiang Gongshang University, Hangzhou, China
| | - Lie-Feng Ma
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, China
| | - Chao-Dong Qian
- College of Life Science, Institute of Molecular Medicine, Zhejiang Chinese Medical University, Hangzhou, China
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17
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Appetecchia F, Consalvi S, Scarpecci C, Biava M, Poce G. SAR Analysis of Small Molecules Interfering with Energy-Metabolism in Mycobacterium tuberculosis. Pharmaceuticals (Basel) 2020; 13:E227. [PMID: 32878317 PMCID: PMC7557483 DOI: 10.3390/ph13090227] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/28/2020] [Accepted: 08/28/2020] [Indexed: 12/13/2022] Open
Abstract
Tuberculosis remains the world's top infectious killer: it caused a total of 1.5 million deaths and 10 million people fell ill with TB in 2018. Thanks to TB diagnosis and treatment, mortality has been falling in recent years, with an estimated 58 million saved lives between 2000 and 2018. However, the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mtb strains is a major concern that might reverse this progress. Therefore, the development of new drugs acting upon novel mechanisms of action is a high priority in the global health agenda. With the approval of bedaquiline, which targets mycobacterial energy production, and delamanid, which targets cell wall synthesis and energy production, the energy-metabolism in Mtb has received much attention in the last decade as a potential target to investigate and develop new antimycobacterial drugs. In this review, we describe potent anti-mycobacterial agents targeting the energy-metabolism at different steps with a special focus on structure-activity relationship (SAR) studies of the most advanced compound classes.
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Affiliation(s)
| | | | | | | | - Giovanna Poce
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy; (F.A.); (S.C.); (C.S.); (M.B.)
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18
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Wong CF, Lau AM, Harikishore A, Saw WG, Shin J, Ragunathan P, Bhushan S, Ngan SFC, Sze SK, Bates RW, Dick T, Grüber G. A systematic assessment of mycobacterial F 1 -ATPase subunit ε's role in latent ATPase hydrolysis. FEBS J 2020; 288:818-836. [PMID: 32525613 DOI: 10.1111/febs.15440] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/05/2020] [Accepted: 06/03/2020] [Indexed: 12/20/2022]
Abstract
In contrast to most bacteria, the mycobacterial F1 FO -ATP synthase (α3 :β3 :γ:δ:ε:a:b:b':c9 ) does not perform ATP hydrolysis-driven proton translocation. Although subunits α, γ and ε of the catalytic F1 -ATPase component α3 :β3 :γ:ε have all been implicated in the suppression of the enzyme's ATPase activity, the mechanism remains poorly defined. Here, we brought the central stalk subunit ε into focus by generating the recombinant Mycobacterium smegmatis F1 -ATPase (MsF1 -ATPase), whose 3D low-resolution structure is presented, and its ε-free form MsF1 αβγ, which showed an eightfold ATP hydrolysis increase and provided a defined system to systematically study the segments of mycobacterial ε's suppression of ATPase activity. Deletion of four amino acids at ε's N terminus, mutant MsF1 αβγεΔ2-5 , revealed similar ATP hydrolysis as MsF1 αβγ. Together with biochemical and NMR solution studies of a single, double, triple and quadruple N-terminal ε-mutants, the importance of the first N-terminal residues of mycobacterial ε in structure stability and latency is described. Engineering ε's C-terminal mutant MsF1 αβγεΔ121 and MsF1 αβγεΔ103-121 with deletion of the C-terminal residue D121 and the two C-terminal ɑ-helices, respectively, revealed the requirement of the very C terminus for communication with the catalytic α3 β3 -headpiece and its function in ATP hydrolysis inhibition. Finally, we applied the tools developed during the study for an in silico screen to identify a novel subunit ε-targeting F-ATP synthase inhibitor.
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Affiliation(s)
- Chui-Fann Wong
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Aik-Meng Lau
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Amaravadhi Harikishore
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Wuan-Geok Saw
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Joon Shin
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Priya Ragunathan
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Shashi Bhushan
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, Singapore City, Singapore
| | - So-Fong Cam Ngan
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Roderick W Bates
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Thomas Dick
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore City, Singapore.,Department of Medical Sciences, Hackensack Meridian School of Medicine at Seton Hall University, Nutley, NJ, USA
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
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19
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Calvert MB, Furkert DP, Cooper CB, Brimble MA. Synthetic approaches towards bedaquiline and its derivatives. Bioorg Med Chem Lett 2020; 30:127172. [PMID: 32291133 DOI: 10.1016/j.bmcl.2020.127172] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/04/2020] [Accepted: 04/04/2020] [Indexed: 01/11/2023]
Abstract
Bedaquiline is a diarylquinoline drug that demonstrates potent and selective inhibition of mycobacterial ATP synthase, and is clinically administered for the treatment of multi-drug resistant tuberculosis. Due to its excellent activity and novel mechanism of action, bedaquiline has been the focus of a number of synthetic studies. This review will discuss these synthetic approaches, as well as the synthesis and bioactivity of the numerous derivatives and molecular probes inspired by bedaquiline.
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Affiliation(s)
- Matthew B Calvert
- School of Chemical Sciences, The University of Auckland, Symonds Street, Auckland 1010, New Zealand
| | - Daniel P Furkert
- School of Chemical Sciences, The University of Auckland, Symonds Street, Auckland 1010, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Symonds Street, Auckland 1010, New Zealand
| | - Christopher B Cooper
- Global Alliance for TB Drug Development, 40 Wall Street, New York, NY 10005, USA
| | - Margaret A Brimble
- School of Chemical Sciences, The University of Auckland, Symonds Street, Auckland 1010, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Symonds Street, Auckland 1010, New Zealand.
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20
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TBAJ-876, a 3,5-Dialkoxypyridine Analogue of Bedaquiline, Is Active against Mycobacterium abscessus. Antimicrob Agents Chemother 2020; 64:AAC.02404-19. [PMID: 31964791 PMCID: PMC7179298 DOI: 10.1128/aac.02404-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/13/2020] [Indexed: 12/11/2022] Open
Abstract
Lung disease caused by Mycobacterium abscessus is very difficult to cure, and treatment failure rates are high. The antituberculosis drug bedaquiline (BDQ) is used as salvage therapy against this dreadful disease. However, BDQ is highly lipophilic, displays a long terminal half-life, and presents a cardiotoxicity liability associated with QT interval prolongation. Recent medicinal chemistry campaigns resulted in the discovery of 3,5-dialkoxypyridine analogues of BDQ which are less lipophilic, have higher clearance, and display lower cardiotoxic potential. Lung disease caused by Mycobacterium abscessus is very difficult to cure, and treatment failure rates are high. The antituberculosis drug bedaquiline (BDQ) is used as salvage therapy against this dreadful disease. However, BDQ is highly lipophilic, displays a long terminal half-life, and presents a cardiotoxicity liability associated with QT interval prolongation. Recent medicinal chemistry campaigns resulted in the discovery of 3,5-dialkoxypyridine analogues of BDQ which are less lipophilic, have higher clearance, and display lower cardiotoxic potential. TBAJ-876, a clinical development candidate of this series, shows attractive in vitro antitubercular activity and efficacy in a murine tuberculosis model. Here, we asked whether TBAJ-876 is active against M. abscessus. TBAJ-876 displayed submicromolar in vitro activity against reference strains representing the three subspecies of M. abscessus and against a collection of clinical isolates. Drug-drug potency interaction studies with commonly used anti-M. abscessus antibiotics showed no antagonistic effects, suggesting that TBAJ-876 could be coadministered with currently used drugs. Efficacy studies, employing a mouse model of M. abscessus infection, demonstrated potent activity in vivo. In summary, we demonstrate that TBAJ-876 shows attractive in vitro and in vivo activities against M. abscessus, similar to its BDQ parent. This suggests that next-generation BDQ, with improved tolerability and pharmacological profiles, may be useful for the treatment of M. abscessus lung disease in addition to the treatment of tuberculosis.
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21
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Re-Understanding the Mechanisms of Action of the Anti-Mycobacterial Drug Bedaquiline. Antibiotics (Basel) 2019; 8:antibiotics8040261. [PMID: 31835707 PMCID: PMC6963887 DOI: 10.3390/antibiotics8040261] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 12/07/2019] [Indexed: 12/14/2022] Open
Abstract
Bedaquiline (BDQ) inhibits ATP generation in Mycobacterium tuberculosis by interfering with the F-ATP synthase activity. Two mechanisms of action of BDQ are broadly accepted. A direct mechanism involves BDQ binding to the enzyme’s c-ring to block its rotation, thus inhibiting ATP synthesis in the enzyme’s catalytic α3β3-headpiece. An indirect mechanism involves BDQ uncoupling electron transport in the electron transport chain from ATP synthesis at the F-ATP synthase. In a recently uncovered second direct mechanism, BDQ binds to the enzyme’s ε-subunit to disrupt its ability to link c-ring rotation to ATP synthesis at the α3β3-headpiece. However, this mechanism is controversial as the drug’s binding affinity for the isolated ε-subunit protein is moderate and spontaneous resistance mutants in the ε-subunit cannot be isolated. Recently, the new, structurally distinct BDQ analogue TBAJ-876 was utilized as a chemical probe to revisit BDQ’s mechanisms of action. In this review, we first summarize discoveries on BDQ’s mechanisms of action and then describe the new insights derived from the studies of TBAJ-876. The TBAJ-876 investigations confirm the c-ring as a target, while also supporting a functional role for targeting the ε-subunit. Surprisingly, the new findings suggest that the uncoupler mechanism does not play a key role in BDQ’s anti-mycobacterial activity.
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