101
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Utilization of CRISPR Interference To Validate MmpL3 as a Drug Target in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2019; 63:AAC.00629-19. [PMID: 31160289 DOI: 10.1128/aac.00629-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 05/29/2019] [Indexed: 12/14/2022] Open
Abstract
There is an urgent need for novel therapeutics to treat Mycobacterium tuberculosis infections. Genetic strategies for validating novel targets are available, yet their time-consuming nature limits their utility. Here, using MmpL3 as a model target, we report on the application of mycobacterial CRISPR interference for the rapid validation of target essentiality and compound mode of action. This strategy has the potential to rapidly accelerate tuberculosis drug discovery.
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102
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Belardinelli JM, Stevens CM, Li W, Tan YZ, Jones V, Mancia F, Zgurskaya HI, Jackson M. The MmpL3 interactome reveals a complex crosstalk between cell envelope biosynthesis and cell elongation and division in mycobacteria. Sci Rep 2019; 9:10728. [PMID: 31341202 PMCID: PMC6656915 DOI: 10.1038/s41598-019-47159-8] [Citation(s) in RCA: 20] [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: 01/08/2019] [Accepted: 07/08/2019] [Indexed: 01/19/2023] Open
Abstract
Integral membrane transporters of the Mycobacterial Membrane Protein Large (MmpL) family and their interactome play important roles in the synthesis and export of mycobacterial outer membrane lipids. Despite the current interest in the mycolic acid transporter, MmpL3, from the perspective of drug discovery, the nature and biological significance of its interactome remain largely unknown. We here report on a genome-wide screening by two-hybrid system for MmpL3 binding partners. While a surprisingly low number of proteins involved in mycolic acid biosynthesis was found to interact with MmpL3, numerous enzymes and transporters participating in the biogenesis of peptidoglycan, arabinogalactan and lipoglycans, and the cell division regulatory protein, CrgA, were identified among the hits. Surface plasmon resonance and co-immunoprecipitation independently confirmed physical interactions for three proteins in vitro and/or in vivo. Results are in line with the focal localization of MmpL3 at the poles and septum of actively-growing bacilli where the synthesis of all major constituents of the cell wall core are known to occur, and are further suggestive of a role for MmpL3 in the coordination of new cell wall deposition during cell septation and elongation. This novel aspect of the physiology of MmpL3 may contribute to the extreme vulnerability and high therapeutic potential of this transporter.
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Affiliation(s)
- Juan Manuel Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523-1682, USA
| | - Casey M Stevens
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK, 73019, USA
| | - Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523-1682, USA
| | - Yong Zi Tan
- Department of Physiology and Cellular Biophysics, Columbia University, 1150 St. Nicholas Avenue, New York, NY, 10032, USA
| | - Victoria Jones
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523-1682, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, 1150 St. Nicholas Avenue, New York, NY, 10032, USA
| | - Helen I Zgurskaya
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK, 73019, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, 80523-1682, USA.
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103
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Mashabela GT, de Wet TJ, Warner DF. Mycobacterium tuberculosis Metabolism. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0067-2019. [PMID: 31350832 PMCID: PMC10957194 DOI: 10.1128/microbiolspec.gpp3-0067-2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Indexed: 02/06/2023] Open
Abstract
Mycobacterium tuberculosis is the cause of tuberculosis (TB), a disease which continues to overwhelm health systems in endemic regions despite the existence of effective combination chemotherapy and the widespread use of a neonatal anti-TB vaccine. For a professional pathogen, M. tuberculosis retains a surprisingly large proportion of the metabolic repertoire found in nonpathogenic mycobacteria with very different lifestyles. Moreover, evidence that additional functions were acquired during the early evolution of the M. tuberculosis complex suggests the organism has adapted (and augmented) the metabolic pathways of its environmental ancestor to persistence and propagation within its obligate human host. A better understanding of M. tuberculosis pathogenicity, however, requires the elucidation of metabolic functions under disease-relevant conditions, a challenge complicated by limited knowledge of the microenvironments occupied and nutrients accessed by bacilli during host infection, as well as the reliance in experimental mycobacteriology on a restricted number of experimental models with variable relevance to clinical disease. Here, we consider M. tuberculosis metabolism within the framework of an intimate host-pathogen coevolution. Focusing on recent advances in our understanding of mycobacterial metabolic function, we highlight unusual adaptations or departures from the better-characterized model intracellular pathogens. We also discuss the impact of these mycobacterial "innovations" on the susceptibility of M. tuberculosis to existing and experimental anti-TB drugs, as well as strategies for targeting metabolic pathways. Finally, we offer some perspectives on the key gaps in the current knowledge of fundamental mycobacterial metabolism and the lessons which might be learned from other systems.
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Affiliation(s)
- Gabriel T Mashabela
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa
- Current address: Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, University of Stellenbosch, South Africa
| | - Timothy J de Wet
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa
- Department of Integrative Biomedical Sciences, University of Cape Town, South Africa
| | - Digby F Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa
- Wellcome Centre for Infectious Disease Research in Africa, University of Cape Town, South Africa
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104
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Abstract
Mycolic acids are the signature lipid of mycobacteria and constitute an important physical component of the cell wall, a target of mycobacterium-specific antibiotics and a mediator of Mycobacterium tuberculosis pathogenesis. Mycolic acids are synthesized in the cytoplasm and are thought to be transported to the cell wall as a trehalose ester by the MmpL3 transporter, an antibiotic target for M. tuberculosis However, the mechanism by which mycolate synthesis is coupled to transport, and the full MmpL3 transport machinery, is unknown. Here, we identify two new components of the MmpL3 transport machinery in mycobacteria. The protein encoded by MSMEG_0736/Rv0383c is essential for growth of Mycobacterium smegmatis and M. tuberculosis and is anchored to the cytoplasmic membrane, physically interacts with and colocalizes with MmpL3 in growing cells, and is required for trehalose monomycolate (TMM) transport to the cell wall. In light of these findings, we propose MSMEG_0736/Rv0383c be named "TMM transport factor A", TtfA. The protein encoded by MSMEG_5308 also interacts with the MmpL3 complex but is nonessential for growth or TMM transport. However, MSMEG_5308 accumulates with inhibition of MmpL3-mediated TMM transport and stabilizes the MmpL3/TtfA complex, indicating that it may stabilize the transport system during stress. These studies identify two new components of the mycobacterial mycolate transport machinery, an emerging antibiotic target in M. tuberculosis IMPORTANCE The cell envelope of Mycobacterium tuberculosis, the bacterium that causes the disease tuberculosis, is a complex structure composed of abundant lipids and glycolipids, including the signature lipid of these bacteria, mycolic acids. In this study, we identified two new components of the transport machinery that constructs this complex cell wall. These two accessory proteins are in a complex with the MmpL3 transporter. One of these proteins, TtfA, is required for mycolic acid transport and cell viability, whereas the other stabilizes the MmpL3 complex. These studies identify two new components of the essential cell envelope biosynthetic machinery in mycobacteria.
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105
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Alsayed SSR, Beh CC, Foster NR, Payne AD, Yu Y, Gunosewoyo H. Kinase Targets for Mycolic Acid Biosynthesis in Mycobacterium tuberculosis. Curr Mol Pharmacol 2019; 12:27-49. [PMID: 30360731 DOI: 10.2174/1874467211666181025141114] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Mycolic acids (MAs) are the characteristic, integral building blocks for the mycomembrane belonging to the insidious bacterial pathogen Mycobacterium tuberculosis (M.tb). These C60-C90 long α-alkyl-β-hydroxylated fatty acids provide protection to the tubercle bacilli against the outside threats, thus allowing its survival, virulence and resistance to the current antibacterial agents. In the post-genomic era, progress has been made towards understanding the crucial enzymatic machineries involved in the biosynthesis of MAs in M.tb. However, gaps still remain in the exact role of the phosphorylation and dephosphorylation of regulatory mechanisms within these systems. To date, a total of 11 serine-threonine protein kinases (STPKs) are found in M.tb. Most enzymes implicated in the MAs synthesis were found to be phosphorylated in vitro and/or in vivo. For instance, phosphorylation of KasA, KasB, mtFabH, InhA, MabA, and FadD32 downregulated their enzymatic activity, while phosphorylation of VirS increased its enzymatic activity. These observations suggest that the kinases and phosphatases system could play a role in M.tb adaptive responses and survival mechanisms in the human host. As the mycobacterial STPKs do not share a high sequence homology to the human's, there have been some early drug discovery efforts towards developing potent and selective inhibitors. OBJECTIVE Recent updates to the kinases and phosphatases involved in the regulation of MAs biosynthesis will be presented in this mini-review, including their known small molecule inhibitors. CONCLUSION Mycobacterial kinases and phosphatases involved in the MAs regulation may serve as a useful avenue for antitubercular therapy.
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Affiliation(s)
- Shahinda S R Alsayed
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
| | - Chau C Beh
- Western Australia School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Bentley 6102 WA, Australia.,David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, United States
| | - Neil R Foster
- Western Australia School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Bentley 6102 WA, Australia
| | - Alan D Payne
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia
| | - Yu Yu
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
| | - Hendra Gunosewoyo
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
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106
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Li W, Stevens CM, Pandya AN, Darzynkiewicz Z, Bhattarai P, Tong W, Gonzalez-Juarrero M, North EJ, Zgurskaya HI, Jackson M. Direct Inhibition of MmpL3 by Novel Antitubercular Compounds. ACS Infect Dis 2019; 5:1001-1012. [PMID: 30882198 PMCID: PMC6580365 DOI: 10.1021/acsinfecdis.9b00048] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
MmpL3, an essential transporter involved in the export of mycolic acids, is the proposed target of a number of antimycobacterial inhibitors under development. Whether MmpL3 serves as the direct target of these compounds, however, has been called into question after the discovery that some of them dissipated the proton motive force from which MmpL transporters derive their energy. Using a combination of in vitro and whole-cell-based approaches, we here provide evidence that five structurally distinct MmpL3 inhibitor series, three of which impact proton motive force in Mycobacterium tuberculosis, directly interact with MmpL3. Medium- to high-throughput assays based on these approaches were developed to facilitate the future screening and optimization of MmpL3 inhibitors. The promiscuity of MmpL3 as a drug target and the mechanisms through which missense mutations located in a transmembrane region of this transporter may confer cross-resistance to a variety of chemical scaffolds are discussed in light of the exquisite vulnerability of MmpL3, its apparent mechanisms of interaction with inhibitors, and evidence of conformational changes induced both by the inhibitors and one of the most commonly identified resistance mutations in MmpL3.
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Affiliation(s)
- Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
| | - Casey M. Stevens
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Amitkumar N. Pandya
- School of Pharmacy & Health Professions, Department of Pharmacy Sciences, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Zbigniew Darzynkiewicz
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Pankaj Bhattarai
- School of Pharmacy & Health Professions, Department of Pharmacy Sciences, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Weiwei Tong
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
| | - E. Jeffrey North
- School of Pharmacy & Health Professions, Department of Pharmacy Sciences, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Helen I. Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
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107
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MmpL3 is a lipid transporter that binds trehalose monomycolate and phosphatidylethanolamine. Proc Natl Acad Sci U S A 2019; 116:11241-11246. [PMID: 31113875 DOI: 10.1073/pnas.1901346116] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cell envelope of Mycobacterium tuberculosis is notable for the abundance of mycolic acids (MAs), essential to mycobacterial viability, and of other species-specific lipids. The mycobacterial cell envelope is extremely hydrophobic, which contributes to virulence and antibiotic resistance. However, exactly how fatty acids and lipidic elements are transported across the cell envelope for cell-wall biosynthesis is unclear. Mycobacterial membrane protein Large 3 (MmpL3) is essential and required for transport of trehalose monomycolates (TMMs), precursors of MA-containing trehalose dimycolates (TDM) and mycolyl arabinogalactan peptidoglycan, but the exact function of MmpL3 remains elusive. Here, we report a crystal structure of Mycobacterium smegmatis MmpL3 at a resolution of 2.59 Å, revealing a monomeric molecule that is structurally distinct from all known bacterial membrane proteins. A previously unknown MmpL3 ligand, phosphatidylethanolamine (PE), was discovered inside this transporter. We also show, via native mass spectrometry, that MmpL3 specifically binds both TMM and PE, but not TDM, in the micromolar range. These observations provide insight into the function of MmpL3 and suggest a possible role for this protein in shuttling a variety of lipids to strengthen the mycobacterial cell wall.
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108
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Fiolek TJ, Banahene N, Kavunja HW, Holmes NJ, Rylski AK, Pohane AA, Siegrist MS, Swarts BM. Engineering the Mycomembrane of Live Mycobacteria with an Expanded Set of Trehalose Monomycolate Analogues. Chembiochem 2019; 20:1282-1291. [PMID: 30589191 PMCID: PMC6614877 DOI: 10.1002/cbic.201800687] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Indexed: 01/20/2023]
Abstract
Mycobacteria and related organisms in the Corynebacterineae suborder are characterized by a distinctive outer membrane referred to as the mycomembrane. Biosynthesis of the mycomembrane occurs through an essential process called mycoloylation, which involves antigen 85 (Ag85)-catalyzed transfer of mycolic acids from the mycoloyl donor trehalose monomycolate (TMM) to acceptor carbohydrates and, in some organisms, proteins. We recently described an alkyne-modified TMM analogue (O-AlkTMM-C7) which, in conjunction with click chemistry, acted as a chemical reporter for mycoloylation in intact cells and allowed metabolic labeling of mycoloylated components of the mycomembrane. Here, we describe the synthesis and evaluation of a toolbox of TMM-based reporters bearing alkyne, azide, trans-cyclooctene, and fluorescent tags. These compounds gave further insight into the substrate tolerance of mycoloyltransferases (e.g., Ag85s) in a cellular context and they provide significantly expanded experimental versatility by allowing one- or two-step cell labeling, live cell labeling, and rapid cell labeling via tetrazine ligation. Such capabilities will facilitate research on mycomembrane composition, biosynthesis, and dynamics. Moreover, because TMM is exclusively metabolized by Corynebacterineae, the described probes may be valuable for the specific detection and cell-surface engineering of Mycobacterium tuberculosis and related pathogens. We also performed experiments to establish the dependence of probe incorporation on mycoloyltransferase activity, results from which suggested that cellular labeling is a function not only of metabolic incorporation (and likely removal) pathway(s), but also accessibility across the envelope. Thus, whole-cell labeling experiments with TMM reporters should be carefully designed and interpreted when envelope permeability may be compromised. On the other hand, this property of TMM reporters can potentially be exploited as a convenient way to probe changes in envelope integrity and permeability, facilitating drug development studies.
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Affiliation(s)
- Taylor J Fiolek
- Department of Chemistry and Biochemistry, Central Michigan University, 1200 S. Franklin St., Mount Pleasant, MI, 48859, USA
| | - Nicholas Banahene
- Department of Chemistry and Biochemistry, Central Michigan University, 1200 S. Franklin St., Mount Pleasant, MI, 48859, USA
| | - Herbert W Kavunja
- Department of Chemistry and Biochemistry, Central Michigan University, 1200 S. Franklin St., Mount Pleasant, MI, 48859, USA
| | - Nathan J Holmes
- Department of Chemistry and Biochemistry, Central Michigan University, 1200 S. Franklin St., Mount Pleasant, MI, 48859, USA
| | - Adrian K Rylski
- Department of Chemistry and Biochemistry, Central Michigan University, 1200 S. Franklin St., Mount Pleasant, MI, 48859, USA
| | - Amol Arunrao Pohane
- Department of Microbiology, University of Massachusetts, 639 N. Pleasant Street, Amherst, MA, 01003, USA
| | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, 639 N. Pleasant Street, Amherst, MA, 01003, USA
| | - Benjamin M Swarts
- Department of Chemistry and Biochemistry, Central Michigan University, 1200 S. Franklin St., Mount Pleasant, MI, 48859, USA
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109
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Zhang W, Lun S, Liu LL, Xiao S, Duan G, Gunosewoyo H, Yang F, Tang J, Bishai WR, Yu LF. Identification of Novel Coumestan Derivatives as Polyketide Synthase 13 Inhibitors against Mycobacterium tuberculosis. Part II. J Med Chem 2019; 62:3575-3589. [DOI: 10.1021/acs.jmedchem.9b00010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - Shichun Lun
- Center for Tuberculosis Research, Department of Medicine, Division of Infectious Disease, Johns Hopkins School of Medicine, Baltimore, Maryland 21231-1044, United States
| | | | - Shiqi Xiao
- Center for Tuberculosis Research, Department of Medicine, Division of Infectious Disease, Johns Hopkins School of Medicine, Baltimore, Maryland 21231-1044, United States
| | | | - Hendra Gunosewoyo
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, Perth, Western Australia 6102, Australia
| | | | | | - William R. Bishai
- Center for Tuberculosis Research, Department of Medicine, Division of Infectious Disease, Johns Hopkins School of Medicine, Baltimore, Maryland 21231-1044, United States
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110
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Melly G, Purdy GE. MmpL Proteins in Physiology and Pathogenesis of M. tuberculosis. Microorganisms 2019; 7:microorganisms7030070. [PMID: 30841535 PMCID: PMC6463170 DOI: 10.3390/microorganisms7030070] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/14/2019] [Accepted: 03/03/2019] [Indexed: 11/16/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) remains an important human pathogen. The Mtb cell envelope is a critical bacterial structure that contributes to virulence and pathogenicity. Mycobacterial membrane protein large (MmpL) proteins export bulky, hydrophobic substrates that are essential for the unique structure of the cell envelope and directly support the ability of Mtb to infect and persist in the host. This review summarizes recent investigations that have enabled insight into the molecular mechanisms underlying MmpL substrate export and the role that these substrates play during Mtb infection.
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Affiliation(s)
- Geoff Melly
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Georgiana E Purdy
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA.
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111
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Jeon AB, Ackart DF, Li W, Jackson M, Melander RJ, Melander C, Abramovitch RB, Chicco AJ, Basaraba RJ, Obregón-Henao A. 2-aminoimidazoles collapse mycobacterial proton motive force and block the electron transport chain. Sci Rep 2019; 9:1513. [PMID: 30728417 PMCID: PMC6365497 DOI: 10.1038/s41598-018-38064-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/18/2018] [Indexed: 12/22/2022] Open
Abstract
There is an urgent need to develop new drugs against tuberculosis. In particular, it is critical to target drug tolerant Mycobacterium tuberculosis (M. tuberculosis), responsible, in part, for the lengthy antibiotic regimen required for treatment. We previously postulated that the presence of in vivo biofilm-like communities of M. tuberculosis could contribute to this drug tolerance. Consistent with this hypothesis, certain 2-aminoimidazole (2-AIs) molecules with anti-biofilm activity were shown to revert mycobacterial drug tolerance in an in vitro M. tuberculosis biofilm model. While exploring their mechanism of action, it was serendipitously observed that these 2-AI molecules also potentiated β-lactam antibiotics by affecting mycobacterial protein secretion and lipid export. As these two bacterial processes are energy-dependent, herein it was evaluated if 2-AI compounds affect mycobacterial bioenergetics. At low concentrations, 2B8, the lead 2-AI compound, collapsed both components of the proton motive force, similar to other cationic amphiphiles. Interestingly, however, the minimum inhibitory concentration of 2B8 against M. tuberculosis correlated with a higher drug concentration determined to interfere with the mycobacterial electron transport chain. Collectively, this study elucidates the mechanism of action of 2-AIs against M. tuberculosis, providing a tool to better understand mycobacterial bioenergetics and develop compounds with improved anti-mycobacterial activity.
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Affiliation(s)
- Albert Byungyun Jeon
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA
- College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave, Gainesville, Florida, 32608, USA
| | - David F Ackart
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Roberta J Melander
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695, USA
- Department of Chemistry & Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana, 46556, USA
| | - Christian Melander
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27695, USA
- Department of Chemistry & Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana, 46556, USA
| | - Robert B Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Adam J Chicco
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Randall J Basaraba
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA.
| | - Andrés Obregón-Henao
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA.
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112
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Abstract
Actinobacteria is a group of diverse bacteria. Most species in this class of bacteria are filamentous aerobes found in soil, including the genus Streptomyces perhaps best known for their fascinating capabilities of producing antibiotics. These bacteria typically have a Gram-positive cell envelope, comprised of a plasma membrane and a thick peptidoglycan layer. However, there is a notable exception of the Corynebacteriales order, which has evolved a unique type of outer membrane likely as a consequence of convergent evolution. In this chapter, we will focus on the unique cell envelope of this order. This cell envelope features the peptidoglycan layer that is covalently modified by an additional layer of arabinogalactan . Furthermore, the arabinogalactan layer provides the platform for the covalent attachment of mycolic acids , some of the longest natural fatty acids that can contain ~100 carbon atoms per molecule. Mycolic acids are thought to be the main component of the outer membrane, which is composed of many additional lipids including trehalose dimycolate, also known as the cord factor. Importantly, a subset of bacteria in the Corynebacteriales order are pathogens of human and domestic animals, including Mycobacterium tuberculosis. The surface coat of these pathogens are the first point of contact with the host immune system, and we now know a number of host receptors specific to molecular patterns exposed on the pathogen's surface, highlighting the importance of understanding how the cell envelope of Actinobacteria is structured and constructed. This chapter describes the main structural and biosynthetic features of major components found in the actinobacterial cell envelopes and highlights the key differences between them.
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Affiliation(s)
- Kathryn C Rahlwes
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA
| | - Ian L Sparks
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA.
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113
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Porter BW, Venkatappa TK. Uncloaking an ancient adversary: Can pathogen biomarker elicitors play a role in confirming extrapulmonary TB and latent TB infection? Tuberculosis (Edinb) 2018; 113:30-37. [PMID: 30514511 DOI: 10.1016/j.tube.2018.08.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 07/07/2018] [Accepted: 08/29/2018] [Indexed: 10/28/2022]
Abstract
Latent tuberculosis infection (LTBI) is diagnosed immunologically using the Mantoux tuberculin skin test (TST) or interferon-gamma release assays (IGRAs). While widely used, immunodiagnostics can produce false negative or false positive results. Pathogen biomarkers provide an alternative, but direct detection in LTBI and extrapulmonary TB cases is challenging. Mycobacterium tuberculosis grows slowly, has limited hematogenous movement, is protected by a lipid rich cell wall, and produces low levels of secreted factors. Here we discuss the potential of elicitors by first considering pathogen markers that may be released following the administration of isoniazid. Isoniazid targets the cell wall of mycobacteria found in extracellular compartments and within monocytes, macrophages, dendritic cells, and lymphatic endothelial cells. Isoniazid's dual-purpose potential as an antibiotic and elicitor is supported by knowledge of latent infection dynamics, time-kill kinetics, and new detection techniques. Within hours, the bactericidal action of isoniazid likely enriches plasma with M. tuberculosis DNA, RNA, proteins/peptides, and lipids. Undoubtedly a portion of these biomarkers are eliminated as some bacilli undergo phagocytosis and lysosomal destruction. However, advances in immunoprecipitation and nucleic acid amplification, combined with the use of larger blood volumes during assay development, may overcome these losses. Other anticipated challenges include determining optimal sample collection times and designing diagnostic workflows that minimize processing-associated marker loss and degradation. Conventional, commercial, and emerging technologies that address these variables are discussed. If realized, isoniazid associated markers could provide proof of concept for novel elicitor-based diagnostic approaches capable of confirming LTBI and empirically treated extrapulmonary TB.
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Affiliation(s)
- Brad W Porter
- Independent Researcher; P.O. Box 56224, Atlanta, GA 30343, USA.
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114
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Shetty A, Xu Z, Lakshmanan U, Hill J, Choong ML, Chng SS, Yamada Y, Poulsen A, Dick T, Gengenbacher M. Novel Acetamide Indirectly Targets Mycobacterial Transporter MmpL3 by Proton Motive Force Disruption. Front Microbiol 2018; 9:2960. [PMID: 30564212 PMCID: PMC6289072 DOI: 10.3389/fmicb.2018.02960] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/16/2018] [Indexed: 02/05/2023] Open
Abstract
To identify novel inhibitors of Mycobacterium tuberculosis cell envelope biosynthesis, we employed a two-step approach. First, we screened the diverse synthetic small molecule 71,544-compound Enamine library for growth inhibitors using the non-pathogenic surrogate Mycobacterium bovis BCG as screening strain and turbidity as readout. Second, 16 confirmed hits were tested for their ability to induce the cell envelope stress responsive promoter piniBAC controlling expression of red fluorescent protein in an M. bovis BCG reporter strain. Using a fluorescence readout, the acetamide E11 was identified. Resistant mutant selection and whole genome sequencing revealed the mycolic acid transporter Mmpl3 as a candidate target of E11. Biochemical analysis using mycobacterial spheroplasts and various membrane assays suggest that E11 indirectly inhibits MmpL3-facilitated translocation of trehalose monomycolates by proton motive force disruption. E11 showed potent bactericidal activity against growing and non-growing M. tuberculosis, low cytotoxic, and hemolytic activity and a dynamic structure activity relationship. In addition to activity against M. tuberculosis, E11 was active against the non-tuberculous mycobacterium M. abscessus, an emerging opportunistic pathogen. In conclusion, we identified a novel bactericidal anti-mycobacterial lead compound targeting MmpL3 providing an attractive starting point for optimization.
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Affiliation(s)
- Annanya Shetty
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Antimicrobial Drug Discovery Laboratory, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Zhujun Xu
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | | | - Jeffrey Hill
- Experimental Therapeutics Center, ASTAR, Singapore, Singapore
| | | | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Singapore Center for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yoshiyuki Yamada
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Anders Poulsen
- Experimental Therapeutics Center, ASTAR, Singapore, Singapore
| | - Thomas Dick
- Antimicrobial Drug Discovery Laboratory, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Martin Gengenbacher
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
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115
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Melzer ES, Sein CE, Chambers JJ, Siegrist MS. DivIVA concentrates mycobacterial cell envelope assembly for initiation and stabilization of polar growth. Cytoskeleton (Hoboken) 2018; 75:498-507. [PMID: 30160378 PMCID: PMC6644302 DOI: 10.1002/cm.21490] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/07/2018] [Accepted: 06/27/2018] [Indexed: 12/31/2022]
Abstract
In many model organisms, diffuse patterning of cell wall peptidoglycan synthesis by the actin homolog MreB enables the bacteria to maintain their characteristic rod shape. In Caulobacter crescentus and Escherichia coli, MreB is also required to sculpt this morphology de novo. Mycobacteria are rod-shaped but expand their cell wall from discrete polar or subpolar zones. In this genus, the tropomyosin-like protein DivIVA is required for the maintenance of cell morphology. DivIVA has also been proposed to direct peptidoglycan synthesis to the tips of the mycobacterial cell. The precise nature of this regulation is unclear, as is its role in creating rod shape from scratch. We find that DivIVA localizes nascent cell wall and covalently associated mycomembrane but is dispensable for the assembly process itself. Mycobacterium smegmatis rendered spherical by peptidoglycan digestion or by DivIVA depletion are able to regain rod shape at the population level in the presence of DivIVA. At the single cell level, there is a close spatiotemporal correlation between DivIVA foci, rod extrusion and concentrated cell wall synthesis. Thus, although the precise mechanistic details differ from other organisms, M. smegmatis also establish and propagate rod shape by cytoskeleton-controlled patterning of peptidoglycan. Our data further support the emerging notion that morphology is a hardwired trait of bacterial cells.
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Affiliation(s)
- Emily S Melzer
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts
| | - Caralyn E Sein
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts
| | - James J Chambers
- Institute for Applied Life Sciences, University of Massachusetts, Amherst, Massachusetts
| | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts.,Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts
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116
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Chao A, Sieminski PJ, Owens CP, Goulding CW. Iron Acquisition in Mycobacterium tuberculosis. Chem Rev 2018; 119:1193-1220. [PMID: 30474981 DOI: 10.1021/acs.chemrev.8b00285] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The highly contagious disease tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis (Mtb), which has been evolving drug resistance at an alarming rate. Like all human pathogens, Mtb requires iron for growth and virulence. Consequently, Mtb iron transport is an emerging drug target. However, the development of anti-TB drugs aimed at these metabolic pathways has been restricted by the dearth of information on Mtb iron acquisition. In this Review, we describe the multiple strategies utilized by Mtb to acquire ferric iron and heme iron. Mtb iron uptake is a complex process, requiring biosynthesis and subsequent export of Mtb siderophores, followed by ferric iron scavenging and ferric-siderophore import into Mtb. Additionally, Mtb possesses two possible heme uptake pathways and an Mtb-specific mechanism of heme degradation that yields iron and novel heme-degradation products. We conclude with perspectives for potential therapeutics that could directly target Mtb heme and iron uptake machineries. We also highlight how hijacking Mtb heme and iron acquisition pathways for drug import may facilitate drug transport through the notoriously impregnable Mtb cell wall.
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Affiliation(s)
| | | | - Cedric P Owens
- Schmid College of Science and Technology , Chapman University , Orange , California 92866 , United States
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117
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Pal R, Hameed S, Fatima Z. Altered drug efflux under iron deprivation unveils abrogated MmpL3 driven mycolic acid transport and fluidity in mycobacteria. Biometals 2018; 32:49-63. [PMID: 30430296 DOI: 10.1007/s10534-018-0157-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 11/12/2018] [Indexed: 11/30/2022]
Abstract
Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) is a global threat to human health hence better understanding of the MTB pathogenesis for improved therapeutics requires immediate attention. Emergence of drug-resistant strains has stimulated an urgent need for adopting new strategies that could be implemented to control TB. One of the contributing mechanisms by which MTB evades drug doses is overexpression of drug efflux pumps. Thus blocking or modulating the functionality of efflux pumps represents an attractive approach to combat drug resistance. Iron is a critical micronutrient required for MTB survival and not freely available inside the host. In this study, we demonstrated that iron deprivation impairs drug efflux pump activity and confers synergism for anti-TB drugs in presence of efflux pump inhibitors against MTB. Mechanistic insights revealed that iron deprivation inhibit resistance nodulation division superfamily transporter activity. This was evident from enhanced Nile red accumulation and reduced expression of MmpL3, a transmembrane promising target involved in mycolic acid transport across membrane. Furthermore, iron deprivation led to abrogated MA transport particularly of class methoxy-MA which was confirmed by TLC and mass spectrometry based lipidome analysis. Additionally, iron deprivation leads to enhanced membrane fluidity in MTB. Together, MmpL3 being a promiscuous anti-TB target, metal chelation strategy could be adopted to boost the effectiveness of current anti-TB drug regimes to combat drug resistance TB.
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Affiliation(s)
- Rahul Pal
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram, Manesar, 122413, India
| | - Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram, Manesar, 122413, India.
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram, Manesar, 122413, India.
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118
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Lee BY, Clemens DL, Silva A, Dillon BJ, Masleša-Galić S, Nava S, Ho CM, Horwitz MA. Ultra-rapid near universal TB drug regimen identified via parabolic response surface platform cures mice of both conventional and high susceptibility. PLoS One 2018; 13:e0207469. [PMID: 30427938 PMCID: PMC6235396 DOI: 10.1371/journal.pone.0207469] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 10/31/2018] [Indexed: 11/23/2022] Open
Abstract
As current treatment of tuberculosis is burdensomely long, provoking non-adherence and drug resistance, effective short-course treatments are needed. Using the output-driven parabolic response surface (PRS) platform, we have identified drug regimens that treat tuberculosis more rapidly in mice than the current Standard Regimen used in humans. We show that PRS Regimen III, comprising clofazimine, SQ109, bedaquiline and pyrazinamide, rapidly sterilizes the lung both in conventionally studied BALB/c mice and in C3HeB/FeJ mice, highly susceptible mice that develop massive necrotic granulomatous lung lesions akin to those in humans, achieving relapse-free cure in only 4 weeks (p<0.0001 versus Standard Regimen). In contrast, the Standard Regimen required 16 weeks to attain lung culture negative status and 20 weeks to achieve relapse-free cure. Thus, PRS Regimen III dramatically cuts by ~80% the time to relapse-free cure in mouse tuberculosis models. PRS Regimen III, with three nonstandard drugs, can potentially treat both drug-sensitive and most drug-resistant tuberculosis.
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Affiliation(s)
- Bai-Yu Lee
- Division of Infectious Diseases, Department of Medicine, University of California, Los Angeles, California, United States of America
| | - Daniel L. Clemens
- Division of Infectious Diseases, Department of Medicine, University of California, Los Angeles, California, United States of America
| | - Aleidy Silva
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California, United States of America
| | - Barbara Jane Dillon
- Division of Infectious Diseases, Department of Medicine, University of California, Los Angeles, California, United States of America
| | - Saša Masleša-Galić
- Division of Infectious Diseases, Department of Medicine, University of California, Los Angeles, California, United States of America
| | - Susana Nava
- Division of Infectious Diseases, Department of Medicine, University of California, Los Angeles, California, United States of America
| | - Chih-Ming Ho
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California, United States of America
- Department of Bioengineering, University of California, Los Angeles, California, United States of America
| | - Marcus A. Horwitz
- Division of Infectious Diseases, Department of Medicine, University of California, Los Angeles, California, United States of America
- * E-mail:
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119
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J Libardo MD, Boshoff HI, Barry CE. The present state of the tuberculosis drug development pipeline. Curr Opin Pharmacol 2018; 42:81-94. [PMID: 30144650 DOI: 10.1016/j.coph.2018.08.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/27/2018] [Accepted: 08/01/2018] [Indexed: 10/28/2022]
Abstract
Tuberculosis now ranks as the leading cause of death in the world due to a single infectious agent. Current standard of care treatment can achieve very high cure rates for drug-sensitive disease but requires a 6-month duration of chemotherapy. Drug-resistant disease requires significantly longer treatment durations with drugs associated with a higher risk of adverse events. Thus, there is a pressing need for a drug regimen that is safer, shorter in duration and superior to current front-line chemotherapy in terms of efficacy. The TB drug pipeline contains several candidates that address one or more of the required attributes of chemotherapeutic regimens that may redefine the standard of care of this disease. Several new drugs have been reported and novel targets have been identified allowing regimens containing new compounds to trickle into clinical studies. Furthermore, a recent paradigm-shift in understanding the pharmacokinetics of anti-tubercular drugs is revolutionizing the way we select compounds for clinical progression.
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Affiliation(s)
- M Daben J Libardo
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, United States
| | - Helena Im Boshoff
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, United States
| | - Clifton E Barry
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, United States.
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120
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Lee BS, Pethe K. Therapeutic potential of promiscuous targets in Mycobacterium tuberculosis. Curr Opin Pharmacol 2018; 42:22-26. [PMID: 30015177 DOI: 10.1016/j.coph.2018.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 05/31/2018] [Accepted: 06/20/2018] [Indexed: 11/16/2022]
Abstract
In the field of tuberculosis drug development, the term 'promiscuous' was coined to collectively describe targets that repeatedly show up in whole-cell screenings. With the current climate leaning towards the exclusion of these targets in future drug screens, this review discusses and clarifies misconceptions surrounding this classification, the prospects of developing compounds targeting promiscuous targets, and their potential impact on tuberculosis drug development. The dominance of these targets in cell-based screens reflect not only bias introduced by experimental setup, but also some of the pathogen's greatest vulnerabilities. Coupled with favourable predictions of their in vivo efficacies and synergism with other TB drugs, these targets open opportunities to be explored for the development of rational drug combination for tuberculosis.
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Affiliation(s)
- Bei Shi Lee
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kevin Pethe
- School of Biological Sciences, Nanyang Technological University, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Singapore.
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121
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Li W, Yazidi A, Pandya AN, Hegde P, Tong W, Calado Nogueira de Moura V, North EJ, Sygusch J, Jackson M. MmpL3 as a Target for the Treatment of Drug-Resistant Nontuberculous Mycobacterial Infections. Front Microbiol 2018; 9:1547. [PMID: 30042757 PMCID: PMC6048240 DOI: 10.3389/fmicb.2018.01547] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 06/21/2018] [Indexed: 12/15/2022] Open
Abstract
Nontuberculous mycobacterial (NTM) pulmonary infections are emerging as a global health problem and pose a threat to susceptible individuals with structural or functional lung conditions such as cystic fibrosis, chronic obstructive pulmonary disease and bronchiectasis. Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex (MABSC) species account for 70–95% of the pulmonary NTM infections worldwide. Treatment options for these pathogens are limited, involve lengthy multidrug regimens of 12–18 months with parenteral and oral drugs, and their outcome is often suboptimal. Development of new drugs and improved regimens to treat NTM infections are thus greatly needed. In the last 2 years, the screening of compound libraries against M. abscessus in culture has led to the discovery of a number of different chemotypes that target MmpL3, an essential inner membrane transporter involved in the export of the building blocks of the outer membrane of all mycobacteria known as the mycolic acids. This perspective reflects on the therapeutic potential of MmpL3 in Mycobacterium tuberculosis and NTM and the possible reasons underlying the outstanding promiscuity of this target. It further analyzes the physiological and structural factors that may account for the apparent looser structure-activity relationship of some of these compound series against M. tuberculosis compared to NTM.
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Affiliation(s)
- Wei Li
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Amira Yazidi
- Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada.,Groupe d'Étude des Protéines Membranaires, Université de Montréal, Montréal, QC, Canada
| | - Amitkumar N Pandya
- Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Creighton University, Omaha, NE, United States
| | - Pooja Hegde
- Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Creighton University, Omaha, NE, United States
| | - Weiwei Tong
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Vinicius Calado Nogueira de Moura
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - E Jeffrey North
- Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Creighton University, Omaha, NE, United States
| | - Jurgen Sygusch
- Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada.,Groupe d'Étude des Protéines Membranaires, Université de Montréal, Montréal, QC, Canada
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
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122
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HC2091 Kills Mycobacterium tuberculosis by Targeting the MmpL3 Mycolic Acid Transporter. Antimicrob Agents Chemother 2018; 62:AAC.02459-17. [PMID: 29661875 DOI: 10.1128/aac.02459-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/09/2018] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis, caused by the intracellular pathogen Mycobacterium tuberculosis, is a deadly disease that requires a long course of treatment. The emergence of drug-resistant strains has driven efforts to discover new small molecules that can kill the bacterium. Here, we report characterizations of the compound HC2091, which kills M. tuberculosis in a time- and dose-dependent manner in vitro and inhibits M. tuberculosis growth in macrophages. Whole-genome sequencing of spontaneous HC2091-resistant mutants identified single-nucleotide variants in the mmpL3 mycolic acid transporter gene. HC2091-resistant mutants do not exhibit cross-resistance with the well-characterized Mycobacterium membrane protein large 3 (MmpL3) inhibitor SQ109, suggesting a distinct mechanism of interaction with MmpL3. Additionally, HC2091 does not modulate bacterial membrane potential or kill nonreplicating M. tuberculosis, thus acting differently from other known MmpL3 inhibitors. RNA sequencing (RNA-seq) transcriptional profiling and lipid profiling of M. tuberculosis treated with HC2091 or SQ109 show that the two compounds target a similar pathway. HC2091 has a chemical structure dissimilar to those of previously described MmpL3 inhibitors, supporting the notion that HC2091 is a new class of MmpL3 inhibitor.
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123
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A uniform cloning platform for mycobacterial genetics and protein production. Sci Rep 2018; 8:9539. [PMID: 29934571 PMCID: PMC6015033 DOI: 10.1038/s41598-018-27687-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/08/2018] [Indexed: 12/31/2022] Open
Abstract
Molecular research on mycobacteria relies on a multitude of tools for the genetic manipulation of these clinically important bacteria. However, a uniform set of vectors allowing for standardized cloning procedures is not available. Here, we developed a versatile series of mycobacterial vectors for gene deletion, complementation and protein production and purification. The vectors are compatible with fragment exchange (FX) cloning, a recently developed high-throughput cloning principle taking advantage of the type IIS restriction enzyme SapI and its capacity to generate sticky trinucleotide ends outside of its recognition sequence. FX cloning allows for the efficient cloning into an entry vector and the facile transfer of the sequenced insert into a variety of destination vectors. We generated a set of mycobacterial expression vectors spanning a wide range of expression strengths, tagging variants and selection markers to rapidly screen for the optimal expression construct in order to purify membrane proteins from the model organism Mycobacterium smegmatis. Further, we generated a series of suicide vectors containing two counterselection markers and used them to delete twenty genes encoding for potential drug efflux pumps in M. smegmatis. The vectors will further facilitate genetic and biochemical research on various mycobacterial species.
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124
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Abstract
After decades of relative inactivity, a large increase in efforts to discover antitubercular therapeutics has brought insights into the biology of Mycobacterium tuberculosis (Mtb) and promising new drugs such as bedaquiline, which inhibits ATP synthase, and the nitroimidazoles delamanid and pretomanid, which inhibit both mycolic acid synthesis and energy production. Despite these advances, the drug discovery pipeline remains underpopulated. The field desperately needs compounds with novel mechanisms of action capable of inhibiting multi- and extensively drug -resistant Mtb (M/XDR-TB) and, potentially, nonreplicating Mtb with the hope of shortening the duration of required therapy. New knowledge about Mtb, along with new methods and technologies, has driven exploration into novel target areas, such as energy production and central metabolism, that diverge from the classical targets in macromolecular synthesis. Here, we review new small molecule drug candidates that act on these novel targets to highlight the methods and perspectives advancing the field. These new targets bring with them the aspiration of shortening treatment duration as well as a pipeline of effective regimens against XDR-TB, positioning Mtb drug discovery to become a model for anti-infective discovery.
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Affiliation(s)
- Samantha Wellington
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, Massachusetts 02142, United States
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Deborah T. Hung
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, Massachusetts 02142, United States
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
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125
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Wu ML, Aziz DB, Dartois V, Dick T. NTM drug discovery: status, gaps and the way forward. Drug Discov Today 2018; 23:1502-1519. [PMID: 29635026 DOI: 10.1016/j.drudis.2018.04.001] [Citation(s) in RCA: 174] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/09/2018] [Accepted: 04/03/2018] [Indexed: 12/22/2022]
Abstract
Incidence of pulmonary diseases caused by non-tuberculous mycobacteria (NTM), relatives of Mycobacterium tuberculosis, is increasing at an alarming rate, surpassing tuberculosis in many countries. Current chemotherapies require long treatment times and the clinical outcomes are often disappointing. There is an urgent medical need to discover and develop new, more-efficacious anti-NTM drugs. In this review, we summarize the current status of NTM drug development, and highlight knowledge gaps and scientific obstacles in NTM drug discovery. We propose strategies to reduce biological uncertainties and to begin to populate a NTM drug pipeline with attractive leads and drug candidates.
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Affiliation(s)
- Mu-Lu Wu
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, 117599, Singapore
| | - Dinah B Aziz
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, 117599, Singapore
| | - Véronique Dartois
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, 225 Warren Street, Newark, NJ 07103, USA
| | - Thomas Dick
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, 225 Warren Street, Newark, NJ 07103, USA.
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126
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RND transporters in the living world. Res Microbiol 2018; 169:363-371. [PMID: 29577985 DOI: 10.1016/j.resmic.2018.03.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 12/22/2022]
Abstract
Transporters of the RND superfamily are well-known as the major drug efflux pumps of Gram-negative bacteria. However, they are widespread in organisms ranging from Archaea to Eukaryotes, and perform diverse functions. This review gives a brief overview of these diverse members of the superfamily with emphasis on their structure and functions.
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127
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Multisystem Analysis of Mycobacterium tuberculosis Reveals Kinase-Dependent Remodeling of the Pathogen-Environment Interface. mBio 2018; 9:mBio.02333-17. [PMID: 29511081 PMCID: PMC5845002 DOI: 10.1128/mbio.02333-17] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tuberculosis is the leading killer among infectious diseases worldwide. Increasing multidrug resistance has prompted new approaches for tuberculosis drug development, including targeted inhibition of virulence determinants and of signaling cascades that control many downstream pathways. We used a multisystem approach to determine the effects of a potent small-molecule inhibitor of the essential Mycobacterium tuberculosis Ser/Thr protein kinases PknA and PknB. We observed differential levels of phosphorylation of many proteins and extensive changes in levels of gene expression, protein abundance, cell wall lipids, and intracellular metabolites. The patterns of these changes indicate regulation by PknA and PknB of several pathways required for cell growth, including ATP synthesis, DNA synthesis, and translation. These data also highlight effects on pathways for remodeling of the mycobacterial cell envelope via control of peptidoglycan turnover, lipid content, a SigE-mediated envelope stress response, transmembrane transport systems, and protein secretion systems. Integrated analysis of phosphoproteins, transcripts, proteins, and lipids identified an unexpected pathway whereby threonine phosphorylation of the essential response regulator MtrA decreases its DNA binding activity. Inhibition of this phosphorylation is linked to decreased expression of genes for peptidoglycan turnover, and of genes for mycolyl transferases, with concomitant changes in mycolates and glycolipids in the cell envelope. These findings reveal novel roles for PknA and PknB in regulating multiple essential cell functions and confirm that these kinases are potentially valuable targets for new antituberculosis drugs. In addition, the data from these linked multisystems provide a valuable resource for future targeted investigations into the pathways regulated by these kinases in the M. tuberculosis cell. Tuberculosis is the leading killer among infectious diseases worldwide. Increasing drug resistance threatens efforts to control this epidemic; thus, new antitubercular drugs are urgently needed. We performed an integrated, multisystem analysis of Mycobacterium tuberculosis responses to inhibition of its two essential serine/threonine protein kinases. These kinases allow the bacterium to adapt to its environment by phosphorylating cellular proteins in response to extracellular signals. We identified differentially phosphorylated proteins, downstream changes in levels of specific mRNA and protein abundance, and alterations in the metabolite and lipid content of the cell. These results include changes previously linked to growth arrest and also reveal new roles for these kinases in regulating essential processes, including growth, stress responses, transport of proteins and other molecules, and the structure of the mycobacterial cell envelope. Our multisystem data identify PknA and PknB as promising targets for drug development and provide a valuable resource for future investigation of their functions.
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128
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Evans JC, Mizrahi V. Priming the tuberculosis drug pipeline: new antimycobacterial targets and agents. Curr Opin Microbiol 2018; 45:39-46. [PMID: 29482115 DOI: 10.1016/j.mib.2018.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 02/12/2018] [Indexed: 12/17/2022]
Abstract
Claiming close to two million lives each year, tuberculosis is now the leading cause of death from an infectious disease. The rise in number of Mycobacterium tuberculosis (Mtb) strains resistant to existing TB drugs has underscored the urgent need to develop new antimycobacterials with novel mechanisms of action. To meet this need, a drug pipeline has been established that is populated with new and repurposed drugs. Recent advances in identifying molecules with inhibitory activity against Mtb under conditions modelled on those encountered during infection, and in elucidating their mechanisms of action, have primed the pipeline with promising drug/target couples, hit compounds and new targets. In this review, we highlight recent advances and emerging areas of opportunity in this field.
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Affiliation(s)
- Joanna C Evans
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research & Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine and Department of Pathology, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Valerie Mizrahi
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research & Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine and Department of Pathology, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa.
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129
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Zampieri M, Szappanos B, Buchieri MV, Trauner A, Piazza I, Picotti P, Gagneux S, Borrell S, Gicquel B, Lelievre J, Papp B, Sauer U. High-throughput metabolomic analysis predicts mode of action of uncharacterized antimicrobial compounds. Sci Transl Med 2018; 10:eaal3973. [PMID: 29467300 PMCID: PMC6544516 DOI: 10.1126/scitranslmed.aal3973] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 04/11/2017] [Accepted: 09/27/2017] [Indexed: 12/19/2022]
Abstract
Rapidly spreading antibiotic resistance and the low discovery rate of new antimicrobial compounds demand more effective strategies for early drug discovery. One bottleneck in the drug discovery pipeline is the identification of the modes of action (MoAs) of new compounds. We have developed a rapid systematic metabolome profiling strategy to classify the MoAs of bioactive compounds. The method predicted MoA-specific metabolic responses in the nonpathogenic bacterium Mycobacterium smegmatis after treatment with 62 reference compounds with known MoAs and different metabolic and nonmetabolic targets. We then analyzed a library of 212 new antimycobacterial compounds with unknown MoAs from a drug discovery effort by the pharmaceutical company GlaxoSmithKline (GSK). More than 70% of these new compounds induced metabolic responses in M. smegmatis indicative of known MoAs, seven of which were experimentally validated. Only 8% (16) of the compounds appeared to target unconventional cellular processes, illustrating the difficulty in discovering new antibiotics with different MoAs among compounds used as monotherapies. For six of the GSK compounds with potentially new MoAs, the metabolome profiles suggested their ability to interfere with trehalose and lipid metabolism. This was supported by whole-genome sequencing of spontaneous drug-resistant mutants of the pathogen Mycobacterium tuberculosis and in vitro compound-proteome interaction analysis for one of these compounds. Our compendium of drug-metabolome profiles can be used to rapidly query the MoAs of uncharacterized antimicrobial compounds and should be a useful resource for the drug discovery community.
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Affiliation(s)
- Mattia Zampieri
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland.
| | - Balazs Szappanos
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Maria Virginia Buchieri
- Mycobacterial Genetics Unit, Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - Andrej Trauner
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Ilaria Piazza
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Paola Picotti
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Sébastien Gagneux
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Sonia Borrell
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Brigitte Gicquel
- Mycobacterial Genetics Unit, Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - Joel Lelievre
- Disease of the Developing World, GlaxoSmithKline, Severo Ochoa, Tres Cantos, Madrid 28760, Spain
| | - Balazs Papp
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Uwe Sauer
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
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130
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Wilson CR, Gessner RK, Moosa A, Seldon R, Warner DF, Mizrahi V, Soares de Melo C, Simelane SB, Nchinda A, Abay E, Taylor D, Njoroge M, Brunschwig C, Lawrence N, Boshoff HIM, Barry CE, Sirgel FA, van Helden P, Harris CJ, Gordon R, Ghidelli-Disse S, Pflaumer H, Boesche M, Drewes G, Sanz O, Santos G, Rebollo-Lopez MJ, Urones B, Selenski C, Lafuente-Monasterio MJ, Axtman M, Lelièvre J, Ballell L, Mueller R, Street LJ, Ghorpade SR, Chibale K. Novel Antitubercular 6-Dialkylaminopyrimidine Carboxamides from Phenotypic Whole-Cell High Throughput Screening of a SoftFocus Library: Structure-Activity Relationship and Target Identification Studies. J Med Chem 2017; 60:10118-10134. [PMID: 29148755 PMCID: PMC5748279 DOI: 10.1021/acs.jmedchem.7b01347] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
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A BioFocus
DPI SoftFocus library of ∼35 000 compounds was screened
against Mycobacterium tuberculosis (Mtb) in order
to identify novel hits with antitubercular activity. The hits were
evaluated in biology triage assays to exclude compounds suggested to function via frequently encountered promiscuous mechanisms of action including inhibition of the QcrB subunit of the cytochrome bc1 complex, disruption of cell–wall homeostasis, and DNA damage. Among the hits that passed this screening cascade, a 6-dialkylaminopyrimidine carboxamide series was prioritized for hit to lead optimization. Compounds from this series were active against clinical Mtb strains, while no cross-resistance to conventional antituberculosis drugs was observed. This suggested a novel mechanism of action, which was confirmed by chemoproteomic analysis leading to the identification of BCG_3193 and BCG_3827 as putative targets of the series with unknown function. Initial structure–activity relationship studies have resulted in compounds with moderate to potent antitubercular activity and improved physicochemical properties.
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Affiliation(s)
- Colin R Wilson
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa
| | - Richard K Gessner
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa
| | - Atica Moosa
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape Town , Rondebosch 7701, South Africa
| | - Ronnett Seldon
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa.,Institute of Infectious Disease and Molecular Medicine, University of Cape Town , Rondebosch 7701, South Africa
| | - Digby F Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape Town , Rondebosch 7701, South Africa.,Institute of Infectious Disease and Molecular Medicine, University of Cape Town , Rondebosch 7701, South Africa
| | - Valerie Mizrahi
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape Town , Rondebosch 7701, South Africa.,Institute of Infectious Disease and Molecular Medicine, University of Cape Town , Rondebosch 7701, South Africa
| | - Candice Soares de Melo
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa
| | - Sandile B Simelane
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa
| | - Aloysius Nchinda
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa
| | - Efrem Abay
- Department of Medicine, Division of Clinical Pharmacology, Drug Discovery and Development Centre (H3D), University of Cape Town , Observatory, 7925, South Africa
| | - Dale Taylor
- Department of Medicine, Division of Clinical Pharmacology, Drug Discovery and Development Centre (H3D), University of Cape Town , Observatory, 7925, South Africa
| | - Mathew Njoroge
- Department of Medicine, Division of Clinical Pharmacology, Drug Discovery and Development Centre (H3D), University of Cape Town , Observatory, 7925, South Africa
| | - Christel Brunschwig
- Department of Medicine, Division of Clinical Pharmacology, Drug Discovery and Development Centre (H3D), University of Cape Town , Observatory, 7925, South Africa
| | - Nina Lawrence
- Department of Medicine, Division of Clinical Pharmacology, Drug Discovery and Development Centre (H3D), University of Cape Town , Observatory, 7925, South Africa
| | - Helena I M Boshoff
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Clifton E Barry
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Frederick A Sirgel
- DST/NRF Centre of Excellence for Biomedical TB Research, SA MRC Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Health Sciences, Stellenbosch University , 7505 Tygerberg, South Africa
| | - Paul van Helden
- DST/NRF Centre of Excellence for Biomedical TB Research, SA MRC Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Health Sciences, Stellenbosch University , 7505 Tygerberg, South Africa
| | - C John Harris
- CJH Consultants , Ford Cottage, South Weirs, Brockenhurst, Hampshire SO42 7UQ, U.K
| | - Richard Gordon
- Strategic Health Innovation Partnerships (SHIP), South African Medical Research Council , Parow Valley, Cape Town, South Africa
| | - Sonja Ghidelli-Disse
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline , Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Hannah Pflaumer
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline , Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Markus Boesche
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline , Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Gerard Drewes
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline , Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Olalla Sanz
- Diseases of the Developing World, GlaxoSmithKline , Calle Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Gracia Santos
- Diseases of the Developing World, GlaxoSmithKline , Calle Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Maria José Rebollo-Lopez
- Diseases of the Developing World, GlaxoSmithKline , Calle Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Beatriz Urones
- Diseases of the Developing World, GlaxoSmithKline , Calle Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Carolyn Selenski
- Diseases of the Developing World, GlaxoSmithKline , Calle Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | | | - Matthew Axtman
- Diseases of the Developing World, GlaxoSmithKline , Calle Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Joël Lelièvre
- Diseases of the Developing World, GlaxoSmithKline , Calle Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Lluis Ballell
- Diseases of the Developing World, GlaxoSmithKline , Calle Severo Ochoa 2, 28760 Tres Cantos, Madrid, Spain
| | - Rudolf Mueller
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa
| | - Leslie J Street
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa
| | - Sandeep R Ghorpade
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa
| | - Kelly Chibale
- Department of Chemistry, Drug Discovery and Development Centre (H3D), University of Cape Town , Rondebosch 7701, South Africa.,Institute of Infectious Disease and Molecular Medicine, University of Cape Town , Rondebosch 7701, South Africa.,South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry, University of Cape Town , Rondebosch 7701, South Africa
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131
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Reiche MA, Warner DF, Mizrahi V. Targeting DNA Replication and Repair for the Development of Novel Therapeutics against Tuberculosis. Front Mol Biosci 2017; 4:75. [PMID: 29184888 PMCID: PMC5694481 DOI: 10.3389/fmolb.2017.00075] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/31/2017] [Indexed: 12/11/2022] Open
Abstract
Mycobacterium tuberculosis is the etiological agent of tuberculosis (TB), an infectious disease which results in approximately 10 million incident cases and 1.4 million deaths globally each year, making it the leading cause of mortality from infection. An effective frontline combination chemotherapy exists for TB; however, this regimen requires the administration of four drugs in a 2 month long intensive phase followed by a continuation phase of a further 4 months with two of the original drugs, and is only effective for the treatment of drug-sensitive TB. The emergence and global spread of multidrug-resistant (MDR) as well as extensively drug-resistant (XDR) strains of M. tuberculosis, and the complications posed by co-infection with the human immunodeficiency virus (HIV) and other co-morbidities such as diabetes, have prompted urgent efforts to develop shorter regimens comprising new compounds with novel mechanisms of action. This demands that researchers re-visit cellular pathways and functions that are essential to M. tuberculosis survival and replication in the host but which are inadequately represented amongst the targets of current anti-mycobacterial agents. Here, we consider the DNA replication and repair machinery as a source of new targets for anti-TB drug development. Like most bacteria, M. tuberculosis encodes a complex array of proteins which ensure faithful and accurate replication and repair of the chromosomal DNA. Many of these are essential; so, too, are enzymes in the ancillary pathways of nucleotide biosynthesis, salvage, and re-cycling, suggesting the potential to inhibit replication and repair functions at multiple stages. To this end, we provide an update on the state of chemotherapeutic inhibition of DNA synthesis and related pathways in M. tuberculosis. Given the established links between genotoxicity and mutagenesis, we also consider the potential implications of targeting DNA metabolic pathways implicated in the development of drug resistance in M. tuberculosis, an organism which is unusual in relying exclusively on de novo mutations and chromosomal rearrangements for evolution, including the acquisition of drug resistance. In that context, we conclude by discussing the feasibility of targeting mutagenic pathways in an ancillary, “anti-evolution” strategy aimed at protecting existing and future TB drugs.
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Affiliation(s)
- Michael A Reiche
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Digby F Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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132
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Sandhu P, Akhter Y. Evolution of structural fitness and multifunctional aspects of mycobacterial RND family transporters. Arch Microbiol 2017; 200:19-31. [PMID: 28951954 DOI: 10.1007/s00203-017-1434-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/07/2017] [Accepted: 09/20/2017] [Indexed: 12/11/2022]
Abstract
Drug resistance is a major concern due to the evolution and emergence of pathogenic bacterial strains with novel strategies to resist the antibiotics in use. Mycobacterium tuberculosis (Mtb) is one of such pathogens with reported strains, which are not treatable with any of the available anti-TB drugs. This scenario has led to the need to look for some novel drug targets in Mtb, which may be exploited to design effective treatment strategies against the infection. The goal of this review is to discuss one such class of emerging drug targets in Mtb. MmpL (mycobacterial membrane protein large) proteins from Mtb are reported to be involved in multi-substrate transport including drug efflux and considered as one of the contributing factors for the emergence of multidrug-resistant strains. MmpL proteins belong to resistance nodulation division permeases superfamily of membrane transporters, which are viably and pathogenetically important and their inhibition could be lethal for the bacteria.
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Affiliation(s)
- Padmani Sandhu
- Structural Bioinformatics Group, Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Shahpur District, Kangra, Himachal Pradesh, 176206, India
| | - Yusuf Akhter
- Structural Bioinformatics Group, Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Shahpur District, Kangra, Himachal Pradesh, 176206, India.
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133
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Viljoen A, Herrmann JL, Onajole OK, Stec J, Kozikowski AP, Kremer L. Controlling Extra- and Intramacrophagic Mycobacterium abscessus by Targeting Mycolic Acid Transport. Front Cell Infect Microbiol 2017; 7:388. [PMID: 28920054 PMCID: PMC5585149 DOI: 10.3389/fcimb.2017.00388] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 08/21/2017] [Indexed: 12/20/2022] Open
Abstract
Mycobacterium abscessus is a rapidly growing mycobacterium (RGM) causing serious infections especially among cystic fibrosis patients. Extremely limited therapeutic options against M. abscessus and a rise in infections with this mycobacterium require novel chemotherapies and a better understanding of how the bacterium causes infection. Different from most RGM, M. abscessus can survive inside macrophages and persist for long durations in infected tissues. We recently delineated differences in the infective programs followed by smooth (S) and rough (R) variants of M. abscessus. Unexpectedly, we found that the S variant behaves like pathogenic slow growing mycobacteria, through maintaining a block on the phagosome maturation process and by inducing phagosome-cytosol communications. On the other hand, R variant infection triggers autophagy and apoptosis, reminiscent of the way that macrophages control RGM. However, the R variant has an exquisite capacity to form extracellular cords, allowing these bacteria to rapidly divide and evade phagocytosis. Therefore, new chemotherapeutic interventions against M. abscessus need to efficiently deal with both the reservoir of intracellular bacilli and the extracellular cords. In this context, we recently identified two chemical entities that were very effective against both M. abscessus populations. Although being structurally unrelated these two chemotypes inhibit the activity of the essential mycolic acid transporter, MmpL3. In this Perspective, we aimed to highlight recent insights into how M. abscessus interacts with phagocytic cells and how the inhibition of mycolic acid transport in this pathogenic RGM could be an efficient means to control both intracellular and extracellular populations of the bacterium.
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Affiliation(s)
- Albertus Viljoen
- Centre National de la Recherche Scientifique UMR9004, Institut de Recherche en Infectiologie de Montpellier, Université de MontpellierMontpellier, France
| | - Jean-Louis Herrmann
- UMR1173, INSERM and UFR Des Sciences de la Santé Simone Veil, Université de Versailles Saint QuentinMontigny-le-Bretonneux, France
| | - Oluseye K Onajole
- Department of Biological, Chemical and Physical Sciences, Roosevelt UniversityChicago, IL, United States
| | - Jozef Stec
- Department of Pharmaceutical Sciences, College of Pharmacy, Marshall B. Ketchum UniversityFullerton, CA, United States
| | - Alan P Kozikowski
- StarWise Therapeutics LLC, University Research ParkMadison, WI, United States
| | - Laurent Kremer
- Centre National de la Recherche Scientifique UMR9004, Institut de Recherche en Infectiologie de Montpellier, Université de MontpellierMontpellier, France.,INSERM, IRIM, 34293Montpellier, France
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134
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Wolber JM, Urbanek BL, Meints LM, Piligian BF, Lopez-Casillas IC, Zochowski KM, Woodruff PJ, Swarts BM. The trehalose-specific transporter LpqY-SugABC is required for antimicrobial and anti-biofilm activity of trehalose analogues in Mycobacterium smegmatis. Carbohydr Res 2017; 450:60-66. [PMID: 28917089 DOI: 10.1016/j.carres.2017.08.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 08/03/2017] [Accepted: 08/03/2017] [Indexed: 12/26/2022]
Abstract
Mycobacteria, including the bacterial pathogen that causes human tuberculosis, possess distinctive pathways for synthesizing and utilizing the non-mammalian disaccharide trehalose. Trehalose metabolism is essential for mycobacterial viability and has been linked to in vitro biofilm formation, which may bear relevance to in vivo drug tolerance. Previous research has shown that some trehalose analogues bearing modifications at the 6-position inhibit growth of various mycobacterial species. In this work, 2-, 5-, and 6-position-modified trehalose analogues were synthesized using our previously reported one-step chemoenzymatic method and shown to inhibit growth and biofilm formation in the two-to three-digit micromolar range in Mycobacterium smegmatis. The trehalose-specific ABC transporter LpqY-SugABC was essential for antimicrobial and anti-biofilm activity, suggesting that inhibition by monosubstituted trehalose analogues requires cellular uptake and does not proceed via direct action on extracellular targets such as antigen 85 acyltransferases or trehalose dimycolate hydrolase. Although the potency of the described compounds in in vitro growth and biofilm assays is moderate, this study reports the first trehalose-based mycobacterial biofilm inhibitors and reinforces the concept of exploiting unique sugar uptake pathways to deliver inhibitors and other chemical cargo to mycobacteria.
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Affiliation(s)
- Jeffrey M Wolber
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859, United States
| | - Bailey L Urbanek
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859, United States
| | - Lisa M Meints
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859, United States
| | - Brent F Piligian
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859, United States
| | - Irene C Lopez-Casillas
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859, United States
| | - Kailey M Zochowski
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859, United States
| | - Peter J Woodruff
- Department of Chemistry, University of Southern Maine, Portland, ME 04104, United States
| | - Benjamin M Swarts
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859, United States.
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