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Uptake-independent killing of macrophages by extracellular Mycobacterium tuberculosis aggregates. EMBO J 2023; 42:e113490. [PMID: 36920246 PMCID: PMC10152147 DOI: 10.15252/embj.2023113490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 01/30/2023] [Accepted: 02/23/2023] [Indexed: 03/16/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) infection is initiated by inhalation of bacteria into lung alveoli, where they are phagocytosed by resident macrophages. Intracellular Mtb replication induces the death of the infected macrophages and the release of bacterial aggregates. Here, we show that these aggregates can evade phagocytosis by killing macrophages in a contact-dependent but uptake-independent manner. We use time-lapse fluorescence microscopy to show that contact with extracellular Mtb aggregates triggers macrophage plasma membrane perturbation, cytosolic calcium accumulation, and pyroptotic cell death. These effects depend on the Mtb ESX-1 secretion system, however, this system alone cannot induce calcium accumulation and macrophage death in the absence of the Mtb surface-exposed lipid phthiocerol dimycocerosate. Unexpectedly, we found that blocking ESX-1-mediated secretion of the EsxA/EsxB virulence factors does not eliminate the uptake-independent killing of macrophages and that the 50-kDa isoform of the ESX-1-secreted protein EspB can mediate killing in the absence of EsxA/EsxB secretion. Treatment with an ESX-1 inhibitor reduces uptake-independent killing of macrophages by Mtb aggregates, suggesting that novel therapies targeting this anti-phagocytic mechanism could prevent the propagation of extracellular bacteria within the lung.
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Affiliation(s)
- Chiara Toniolo
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Neeraj Dhar
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland.,Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - John D McKinney
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
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2
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In Silico Pharmacokinetic Profiling of the Identified Bioactive Metabolites of Pergularia tomentosa L. Latex Extract and In Vitro Cytotoxic Activity via the Induction of Caspase-Dependent Apoptosis with S-Phase Arrest. Pharmaceuticals (Basel) 2022; 15:ph15091132. [PMID: 36145353 PMCID: PMC9501251 DOI: 10.3390/ph15091132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
The in vitro cytotoxic efficacy of plant latex from Pergularia tomentosa L. was studied using five human cancer cell lines: HeLa cells (cervical carcinoma cells), A-549 (lung carcinoma), Panc-1 (pancreatic carcinoma cells), MDA-MB-231 (metastatic mammary adenocarcinoma), and MRC-5 (lung fibroblast cell line) cells. The phytonutrient content of plant latex was identified using the liquid chromatography/mass spectra-quadrupole time of flight (LC/MS-QTOF) technique. In silico studies of polyphenols were carried out to clarify the potential mode of action of the plant latex’s constituents. The treatment of different tumor cell lines with different concentrations of plant latex revealed a potent efficacy on the human lung carcinoma cell line (A-549) (IC50 = 3.89 µg/mL) compared with that with vinblastine as a positive control (IC50 = 7.12 µg/mL). The effect of the potent concentration of plant latex on the A-549 cell line induced cell arrest, upregulated the expression of pre-apoptotic markers, and downregulated the expression of antiapoptotic markers. Seven identified polyphenols were selected for the in silico study. A docking assessment using the epidermal growth factor receptor kinase (EGFRk) and eltronib as a positive control showed a higher affinity for the enzyme receptor of the selected polyphenols, except for methyl orsellinate and ginkgotoxin. The ADMET assessment demonstrated the inhibitory effect of the polyphenols on CYP450, except for ouabagenin and xanthyletine. The selected polyphenols obey Lipinski’s drug-likeness with no significant toxicity effect. In conclusion, the plant latex of P. tomentosa L. showed cytotoxic activity on the A-549 cell line, and the selected polyphenols showed a promising prodrug agent with a low profile of toxicity in the study.
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3
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Impact of Tetracationic Calix[4]arene Conformation—from Conic Structure to Expanded Bolaform—on Their Antibacterial and Antimycobacterial Activities. Chembiochem 2019; 20:911-921. [DOI: 10.1002/cbic.201800609] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Maxime Mourer
- Université de LorraineCNRS, L2CMFaculté des Sciences et Technologies Boulevard des Aiguillettes 54506 Vandoeuvre-lès-Nancy France
| | - Raphaël E. Duval
- Université de LorraineCNRS, L2CMFaculté des Sciences et Technologies Boulevard des Aiguillettes 54506 Vandoeuvre-lès-Nancy France
- ABC Platform Nancy 54001 France
| | - Patricia Constant
- Département Tuberculose & Biologie des InfectionsInstitut de Pharmacologie et de Biologie Structurale, UMR 5089Université de ToulouseCNRS, UPS 205 Route de Narbonne 31077 Toulouse Cedex 04 France
| | - Mamadou Daffé
- Département Tuberculose & Biologie des InfectionsInstitut de Pharmacologie et de Biologie Structurale, UMR 5089Université de ToulouseCNRS, UPS 205 Route de Narbonne 31077 Toulouse Cedex 04 France
| | - Jean‐Bernard Regnouf‐de‐Vains
- Université de LorraineCNRS, L2CMFaculté des Sciences et Technologies Boulevard des Aiguillettes 54506 Vandoeuvre-lès-Nancy France
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4
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Small Molecules That Sabotage Bacterial Virulence. Trends Pharmacol Sci 2017; 38:339-362. [PMID: 28209403 DOI: 10.1016/j.tips.2017.01.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/01/2017] [Accepted: 01/06/2017] [Indexed: 02/08/2023]
Abstract
The continued rise of antibiotic-resistant bacterial infections has motivated alternative strategies for target discovery and treatment of infections. Antivirulence therapies function through inhibition of in vivo required virulence factors to disarm the pathogen instead of directly targeting viability or growth. This approach to treating bacteria-mediated diseases may have advantages over traditional antibiotics because it targets factors specific for pathogenesis, potentially reducing selection for resistance and limiting collateral damage to the resident microbiota. This review examines vulnerable molecular mechanisms used by bacteria to cause disease and the antivirulence compounds that sabotage these virulence pathways. By expanding the study of antimicrobial targets beyond those that are essential for growth, antivirulence strategies offer new and innovative opportunities to combat infectious diseases.
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5
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Synthesis and evaluation of analogs of the phenylpyridazinone NPD-001 as potent trypanosomal TbrPDEB1 phosphodiesterase inhibitors and in vitro trypanocidals. Bioorg Med Chem 2016; 24:1573-81. [PMID: 26935942 DOI: 10.1016/j.bmc.2016.02.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 02/21/2016] [Accepted: 02/24/2016] [Indexed: 12/16/2022]
Abstract
Trypanosomal phosphodiesterases B1 and B2 (TbrPDEB1 and TbrPDEB2) play an important role in the life cycle of Trypanosoma brucei, the causative parasite of human African trypanosomiasis (HAT), also known as African sleeping sickness. Knock down of both enzymes leads to cell cycle arrest and is lethal to the parasite. Recently, we reported the phenylpyridazinone, NPD-001, with low nanomolar IC50 values on both TbrPDEB1 (IC50: 4nM) and TbrPDEB2 (IC50: 3nM) (J. Infect. Dis.2012, 206, 229). In this study, we now report on the first structure activity relationships of a series of phenylpyridazinone analogs as TbrPDEB1 inhibitors. A selection of compounds was also shown to be anti-parasitic. Importantly, a good correlation between TbrPDEB1 IC50 and EC50 against the whole parasite was observed. Preliminary analysis of the SAR of selected compounds on TbrPDEB1 and human PDEs shows large differences which shows the potential for obtaining parasite selective PDE inhibitors. The results of these studies support the pharmacological validation of the Trypanosome PDEB family as novel therapeutic approach for HAT and provide as well valuable information for the design of potent TbrPDEB1 inhibitors that could be used for the treatment of this disease.
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Affiliation(s)
- Johan Veerman
- Mercachem, PO Box 6747, 6503 GE Nijmegen, The Netherlands
| | | | - Kristina M Orrling
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines & Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Chimed Jansen
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines & Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Groenenborgerlaan 171, 2020 Wilrijk, Belgium
| | - Louis Maes
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Groenenborgerlaan 171, 2020 Wilrijk, Belgium
| | - Eric Chatelain
- DNDi (Drugs for Neglected Diseases initiative), 15 Chemin Louis Dunant, 1202 Geneva, Switzerland
| | - Jean-Robert Ioset
- DNDi (Drugs for Neglected Diseases initiative), 15 Chemin Louis Dunant, 1202 Geneva, Switzerland
| | - Ewald E Edink
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines & Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Hermann Tenor
- Takeda, Takeda Pharmaceuticals International GmbH, Thurgauerstrasse 130, 8152 Glattpark-Opfikon, Zurich, Switzerland
| | - Thomas Seebeck
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland
| | - Iwan de Esch
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines & Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Rob Leurs
- Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines & Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Geert Jan Sterk
- Mercachem, PO Box 6747, 6503 GE Nijmegen, The Netherlands; Division of Medicinal Chemistry, Faculty of Sciences, Amsterdam Institute of Molecules, Medicines & Systems (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
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6
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Guanidinium compounds with sub-micromolar activities against Mycobacterium tuberculosis . Synthesis, characterization and biological evaluations. Bioorg Med Chem 2015; 23:5410-8. [DOI: 10.1016/j.bmc.2015.07.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 07/17/2015] [Accepted: 07/25/2015] [Indexed: 10/23/2022]
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7
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Anticytolytic screen identifies inhibitors of mycobacterial virulence protein secretion. Cell Host Microbe 2015; 16:538-48. [PMID: 25299337 DOI: 10.1016/j.chom.2014.09.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/20/2014] [Accepted: 09/17/2014] [Indexed: 11/18/2022]
Abstract
Mycobacterium tuberculosis (Mtb) requires protein secretion systems like ESX-1 for intracellular survival and virulence. The major virulence determinant and ESX-1 substrate, EsxA, arrests phagosome maturation and lyses cell membranes, resulting in tissue damage and necrosis that promotes pathogen spread. To identify inhibitors of Mtb protein secretion, we developed a fibroblast survival assay exploiting this phenotype and selected molecules that protect host cells from Mtb-induced lysis without being bactericidal in vitro. Hit compounds blocked EsxA secretion and promoted phagosome maturation in macrophages, thus reducing bacterial loads. Target identification studies led to the discovery of BTP15, a benzothiophene inhibitor of the histidine kinase MprB that indirectly regulates ESX-1, and BBH7, a benzyloxybenzylidene-hydrazine compound. BBH7 affects Mtb metal-ion homeostasis and revealed zinc stress as an activating signal for EsxA secretion. This screening approach extends the target spectrum of small molecule libraries and will help tackle the mounting problem of antibiotic-resistant mycobacteria.
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Affiliation(s)
- Jan Rybniker
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; 1(st) Department of Internal Medicine, University of Cologne, 50937 Cologne, Germany
| | - Jeffrey M Chen
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Claudia Sala
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ruben C Hartkoorn
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anthony Vocat
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andrej Benjak
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Stefanie Boy-Röttger
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ming Zhang
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Rita Székely
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Zoltán Greff
- Vichem Chemie Research Ltd., Herman Otto u. 15, 1022 Budapest, Hungary
| | - László Orfi
- Vichem Chemie Research Ltd., Herman Otto u. 15, 1022 Budapest, Hungary; Department of Pharmaceutical Chemistry, Semmelweis University, Hőgyes Endre u. 9, 1092 Budapest, Hungary
| | - István Szabadkai
- Vichem Chemie Research Ltd., Herman Otto u. 15, 1022 Budapest, Hungary
| | - János Pató
- Vichem Chemie Research Ltd., Herman Otto u. 15, 1022 Budapest, Hungary
| | - György Kéri
- Vichem Chemie Research Ltd., Herman Otto u. 15, 1022 Budapest, Hungary; MTA-SE Pathobiochemistry Research Group, Department of Medical Chemistry, Semmelweis University, 1094 Budapest, Hungary
| | - Stewart T Cole
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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8
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Phenotypic profiling of Mycobacterium tuberculosis EspA point mutants reveals that blockage of ESAT-6 and CFP-10 secretion in vitro does not always correlate with attenuation of virulence. J Bacteriol 2013; 195:5421-30. [PMID: 24078612 DOI: 10.1128/jb.00967-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The EspA protein of Mycobacterium tuberculosis is essential for the type VII ESX-1 protein secretion apparatus, which delivers the principal virulence factors ESAT-6 and CFP-10. In this study, site-directed mutagenesis of EspA was performed to elucidate its influence on the ESX-1 system. Replacing Trp(55) (W55) or Gly(57) (G57) residues in the putative W-X-G motif of EspA with arginines impaired ESAT-6 and CFP-10 secretion in vitro and attenuated M. tuberculosis. Replacing the Phe(50) (F50) and Lys(62) (K62) residues, which flank the W-X-G motif, with arginine and alanine, respectively, destabilized EspA, abolished ESAT-6 and CFP-10 secretion in vitro, and attenuated M. tuberculosis. Likewise, replacing the Phe(5) (F5) and Lys(41) (K41) residues with arginine and alanine, respectively, also destabilized EspA and blocked ESAT-6 and CFP-10 secretion in vitro. However, these two particular mutations did not attenuate M. tuberculosis in cellular models of infection or during acute infection in mice. We have thus identified amino acid residues in EspA that are important for facilitating ESAT-6 and CFP-10 secretion and virulence. However, our data also indicate for the first time that blockage of M. tuberculosis ESAT-6 and CFP-10 secretion in vitro and attenuation are mutually exclusive.
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9
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Mycobacterium tuberculosis EspB binds phospholipids and mediates EsxA-independent virulence. Mol Microbiol 2013; 89:1154-66. [PMID: 23869560 DOI: 10.1111/mmi.12336] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2013] [Indexed: 02/06/2023]
Abstract
The type-VII ESX-1 secretion apparatus, encoded by the esx-1 genetic locus, is essential for the export of EsxA and EsxB, two major virulence factors of Mycobacterium tuberculosis. ESX-1 also requires the products of the unlinked espACD operon for optimal function and these proteins are considered integral parts of the secretion apparatus. Here we show that the espACD operon is not necessary for the secretion of EspB, another ESX-1 substrate, and this unimpeded secretion of EspB is associated with significant residual virulence. Upon further investigation, we found that purified EspB can facilitate M. tb virulence even in the absence of EsxA and EsxB, and may do so by binding the bioactive phospholipids phosphatidic acid and phosphatidylserine, both of which are potent bioactive molecules with prominent roles in eukaryotic cell signalling. Our findings provide new insights into the impact of the espACD operon on the ESX-1 apparatus and reveal a distinct virulence function for EspB with novel implications in M. tb-host interactions.
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Affiliation(s)
- Jeffrey M Chen
- École Polytechnique Fédérale de Lausanne, Global Health Institute, Lausanne, Switzerland
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10
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Potential use of nitrate reductase as a biomarker for the identification of active and dormant inhibitors of Mycobacterium tuberculosis in a THP1 infection model. ACTA ACUST UNITED AC 2012; 17:966-73. [PMID: 22573731 DOI: 10.1177/1087057112445485] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The development of a macrophage-based, antitubercular high-throughput screening system could expedite discovery programs for identifying novel inhibitors. In this study, the kinetics of nitrate reduction (NR) by Mycobacterium tuberculosis during growth in Thp1 macrophages was found to be almost parallel to viable bacilli count. NR in the culture medium containing 50 mM of nitrate was found to be optimum on the fifth day after infection with M. tuberculosis. The signal-to-noise (S/N) ratio and Z-factor obtained from this macrophage-based assay were 5.4 and 0.965, respectively, which confirms the robustness of the assay protocol. The protocol was further validated by using standard antitubercular inhibitors such as rifampicin, isoniazid, streptomycin, ethambutol, and pyrazinamide, added at their IC(90) value, on the day of infection. These inhibitors were not able to kill the bacilli when added to the culture on the fifth day after infection. Interestingly, pentachlorophenol and rifampicin killed the bacilli immediately after addition on the fifth day of infection. Altogether, this assay protocol using M. tuberculosis-infected Thp-1 macrophages provides a novel, cost-efficient, robust, and easy-to-perform screening platform for the identification of both active and hypoxic stage-specific inhibitors against tuberculosis.
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Affiliation(s)
- Sampa Sarkar
- Combichem Bioresource Center, CSIR-National Chemical Laboratory, Pune, India.
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11
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Synthesis of N-substituted 2-[(1E)-alkenyl]-4-(1H)-quinolone derivatives as antimycobacterial agents against non-tubercular mycobacteria. Eur J Med Chem 2011; 46:2091-101. [PMID: 21429630 PMCID: PMC3096000 DOI: 10.1016/j.ejmech.2011.02.062] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Revised: 02/18/2011] [Accepted: 02/24/2011] [Indexed: 11/23/2022]
Abstract
In an effort to improve biological activities and to examine antimycobacterial-lipophilicity relationships of 2-[(1E)-alkenyl)]-4-(1H)-quinolones, we have synthesized a series of 30 quinolones by introducing several alkyl groups, an alkenyl and an alkynyl group at N-1. All synthetic compounds were first tested in vitro against Mycobacterium smegmatis and the most active compounds (MIC values ∼3.0–7.0 μM) were further examined against three other rapidly growing strains of mycobacteria using a microtiter broth dilution assay. The Clog P values of the synthetic compounds were calculated to provide an estimate of their lipophilicity. Compounds 18e, 19a and 19b displayed the most potent inhibitory effect against M. smegmatis mc2155 with an MIC value of ∼1.5 μM, which was twenty fold and thirteen fold more potent than isoniazid and ethambutol, respectively. On the other hand, compounds 17e, 18e and 19a were most active against Mycobacterium fortuitum and Mycobacterium phlei with an MIC value of ∼3.0 μM. In the human diploid embryonic lung cell line MRC-5 cytotoxicity assay, the derivatives showed moderate to strong cytotoxic activity. Although the antimycobacterial activity of our synthetic compounds could not be correlated with the calculated log P values, an increase in lipophilicity enhances the antimycobacterial activity and C13–C15 total chain length at positions 1 and 2 is required to achieve optimal inhibitory effect against the test strains.
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Affiliation(s)
- Abraham A Wube
- Institute of Pharmaceutical Sciences, Department of Pharmacognosy, Karl Franzens Universität Graz, Universitätsplatz 4, A-8010 Graz, Austria
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12
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A simple whole cell based high throughput screening protocol using Mycobacterium bovis BCG for inhibitors against dormant and active tubercle bacilli. J Microbiol Methods 2008; 73:62-8. [PMID: 18328582 DOI: 10.1016/j.mimet.2008.01.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 01/30/2008] [Accepted: 01/31/2008] [Indexed: 10/22/2022]
Abstract
This study aimed at developing a whole cell based high throughput screening protocol to identify inhibitors against both active and dormant tubercle bacilli. A respiratory type of nitrate reductase (NarGHJI), which was induced during dormancy, could reflect the viability of dormant bacilli of Mycobacterium bovis BCG in microplate adopted model of in vitro dormancy. Correlation between reduction in viability and nitrate reductase activity was seen clearly when dormant stage inhibitor metronidazole and itaconic anhydride were applied in this in vitro microplate model. Active replicating stage could also be monitored in the same assay by measuring the A(620) of the culture. MIC values of 0.08, 0.075, 0.3 and 3.0 microg/ml, determined through monitoring A(620) in this assay for rifampin, isoniazid, streptomycin and ethambutol respectively, were well in agreement with previously reported by BACTEC and Bio-Siv assays. S/N ratio and Z' factor for the assay were 8.5 and 0.81 respectively which indicated the robustness of the protocol. Altogether the assay provides an easy, inexpensive, rapid, robust and high content screening tool to search novel antitubercular molecules against both active and dormant bacilli.
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Affiliation(s)
- Arshad Khan
- CombiChem Bio Resource Center, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune-411008, India
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13
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Synthesis of new sugar derivatives from Stachys sieboldi Miq and antibacterial evaluation against Mycobacterium tuberculosis, Mycobacterium avium, and Staphylococcus aureus. Bioorg Med Chem Lett 2007; 17:2487-91. [PMID: 17331717 DOI: 10.1016/j.bmcl.2007.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2006] [Revised: 01/22/2007] [Accepted: 02/09/2007] [Indexed: 11/27/2022]
Abstract
A series of sugar derivatives (7-14) were synthesized from stachyose, a sugar compound of Stachys sieboldi Miq, and evaluated for antibacterial activity against Mycobacterium tuberculosis, Mycobacterium avium, and Staphylococcus aureus, and their structure-activity relationships were studied. The results showed that the compound OCT359 (allyl O-(2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl)-(1-->6)-O-(2,3,4-tri-O-acetyl-alpha-D-galactopyranosyl)-(1-->6)-O-2,3,4-tri-O-acetyl-beta-D-glucopyranoside) (12) exhibited in vitro antibacterial activity. The allyl group at C-1 and the acetoxy groups of the manninotrioside were requisite for the antibacterial activity.
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Affiliation(s)
- Taku Chiba
- Department of Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
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14
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Simple fibroblast-based assay to test the pyrazinamide susceptibility of Mycobacterium tuberculosis. Antimicrob Agents Chemother 2005; 49:804-7. [PMID: 15673774 PMCID: PMC547215 DOI: 10.1128/aac.49.2.804-807.2005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A simple fibroblast-based assay (SFA) was found to be efficient in evaluating the susceptibilities of clinical isolates of Mycobacterium tuberculosis to pyrazinamide (PZA). Forty-five clinical isolates were examined. The MICs of PZA for susceptible strains in an SFA were between 3.13 and 12.5 microg/ml, and the MICs of PZA for resistant strains were more than 100 microg/ml.
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Affiliation(s)
- Takemasa Takii
- Department of Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-Dori, Mizuho-Ku, Nagoya 467-8603, Japan.
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