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Franch O, Han X, Marcussen LB, Givskov A, Andersen MB, Godbole AA, Harmsen C, Nørskov-Lauritsen N, Thomsen J, Pedersen FS, Wang Y, Shi D, Wejse C, Pødenphant L, Nagaraja V, Bertl J, Stougaard M, Ho YP, Hede MS, Labouriau R, Knudsen BR. A new DNA sensor system for specific and quantitative detection of mycobacteria. Nanoscale 2019; 11:587-597. [PMID: 30556557 DOI: 10.1039/c8nr07850e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the current study, we describe a novel DNA sensor system for specific and quantitative detection of mycobacteria, which is the causative agent of tuberculosis. Detection is achieved by using the enzymatic activity of the mycobacterial encoded enzyme topoisomerase IA (TOP1A) as a biomarker. The presented work is the first to describe how the catalytic activities of a member of the type IA family of topoisomerases can be exploited for specific detection of bacteria. The principle for detection relies on a solid support anchored DNA substrate with dual functions namely: (1) the ability to isolate mycobacterial TOP1A from crude samples and (2) the ability to be converted into a closed DNA circle upon reaction with the isolated enzyme. The DNA circle can act as a template for rolling circle amplification generating a tandem repeat product that can be visualized at the single molecule level by fluorescent labelling. This reaction scheme ensures specific, sensitive, and quantitative detection of the mycobacteria TOP1A biomarker as demonstrated by the use of purified mycobacterial TOP1A and extracts from an array of non-mycobacteria and mycobacteria species. When combined with mycobacteriophage induced lysis as a novel way of effective yet gentle extraction of the cellular content from the model Mycobacterium smegmatis, the DNA sensor system allowed detection of mycobacteria in small volumes of cell suspensions. Moreover, it was possible to detect M. smegmatis added to human saliva. Depending on the composition of the sample, we were able to detect 0.6 or 0.9 million colony forming units (CFU) per mL of mycobacteria, which is within the range of clinically relevant infection numbers. We, therefore, believe that the presented assay, which relies on techniques that can be adapted to limited resource settings, may be the first step towards the development of a new point-of-care diagnostic test for tuberculosis.
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Affiliation(s)
- Oskar Franch
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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2
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Mori G, Orena BS, Franch C, Mitchenall LA, Godbole AA, Rodrigues L, Aguilar-Pérez C, Zemanová J, Huszár S, Forbak M, Lane TR, Sabbah M, Deboosere N, Frita R, Vandeputte A, Hoffmann E, Russo R, Connell N, Veilleux C, Jha RK, Kumar P, Freundlich JS, Brodin P, Aínsa JA, Nagaraja V, Maxwell A, Mikušová K, Pasca MR, Ekins S. The EU approved antimalarial pyronaridine shows antitubercular activity and synergy with rifampicin, targeting RNA polymerase. Tuberculosis (Edinb) 2018; 112:98-109. [PMID: 30205975 DOI: 10.1016/j.tube.2018.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 08/03/2018] [Accepted: 08/05/2018] [Indexed: 12/19/2022]
Abstract
The search for compounds with biological activity for many diseases is turning increasingly to drug repurposing. In this study, we have focused on the European Union-approved antimalarial pyronaridine which was found to have in vitro activity against Mycobacterium tuberculosis (MIC 5 μg/mL). In macromolecular synthesis assays, pyronaridine resulted in a severe decrease in incorporation of 14C-uracil and 14C-leucine similar to the effect of rifampicin, a known inhibitor of M. tuberculosis RNA polymerase. Surprisingly, the co-administration of pyronaridine (2.5 μg/ml) and rifampicin resulted in in vitro synergy with an MIC 0.0019-0.0009 μg/mL. This was mirrored in a THP-1 macrophage infection model, with a 16-fold MIC reduction for rifampicin when the two compounds were co-administered versus rifampicin alone. Docking pyronaridine in M. tuberculosis RNA polymerase suggested the potential for it to bind outside of the RNA polymerase rifampicin binding pocket. Pyronaridine was also found to have activity against a M. tuberculosis clinical isolate resistant to rifampicin, and when combined with rifampicin (10% MIC) was able to inhibit M. tuberculosis RNA polymerase in vitro. All these findings, and in particular the synergistic behavior with the antitubercular rifampicin, inhibition of RNA polymerase in combination in vitro and its current use as a treatment for malaria, may suggest that pyronaridine could also be used as an adjunct for treatment against M. tuberculosis infection. Future studies will test potential for in vivo synergy, clinical utility and attempt to develop pyronaridine analogs with improved potency against M. tuberculosis RNA polymerase when combined with rifampicin.
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Affiliation(s)
- Giorgia Mori
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Beatrice Silvia Orena
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Clara Franch
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Lesley A Mitchenall
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Adwait Anand Godbole
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Liliana Rodrigues
- Departamento de Microbiología, Facultad de Medicina, and BIFI, Universidad de Zaragoza, and IIS-Aragón, 50009 Zaragoza, Spain; CIBER Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Spain; Fundación ARAID, Zaragoza, Spain
| | - Clara Aguilar-Pérez
- Departamento de Microbiología, Facultad de Medicina, and BIFI, Universidad de Zaragoza, and IIS-Aragón, 50009 Zaragoza, Spain; CIBER Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Spain
| | - Júlia Zemanová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 84215, Bratislava, Slovakia
| | - Stanislav Huszár
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 84215, Bratislava, Slovakia
| | - Martin Forbak
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 84215, Bratislava, Slovakia
| | - Thomas R Lane
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA
| | - Mohamad Sabbah
- Department of Chemistry, University of Cambridge, Lensfield Rd, Cambridge, CB2 1EW, UK
| | - Nathalie Deboosere
- Univ Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, 1 rue du Professeur Calmette, 59000 Lille, France
| | - Rosangela Frita
- Univ Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, 1 rue du Professeur Calmette, 59000 Lille, France
| | - Alexandre Vandeputte
- Univ Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, 1 rue du Professeur Calmette, 59000 Lille, France
| | - Eik Hoffmann
- Univ Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, 1 rue du Professeur Calmette, 59000 Lille, France
| | - Riccardo Russo
- Division of Infectious Disease, Department of Medicine and the Ruy V. Lourenço Center for the Study of Emerging and Re-emerging Pathogens, Rutgers University - New Jersey Medical School, Newark, NJ 07103, USA
| | - Nancy Connell
- Division of Infectious Disease, Department of Medicine and the Ruy V. Lourenço Center for the Study of Emerging and Re-emerging Pathogens, Rutgers University - New Jersey Medical School, Newark, NJ 07103, USA
| | - Courtney Veilleux
- Division of Infectious Disease, Department of Medicine and the Ruy V. Lourenço Center for the Study of Emerging and Re-emerging Pathogens, Rutgers University - New Jersey Medical School, Newark, NJ 07103, USA
| | - Rajiv K Jha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Pradeep Kumar
- Division of Infectious Disease, Department of Medicine and the Ruy V. Lourenço Center for the Study of Emerging and Re-emerging Pathogens, Rutgers University - New Jersey Medical School, Newark, NJ 07103, USA
| | - Joel S Freundlich
- Division of Infectious Disease, Department of Medicine and the Ruy V. Lourenço Center for the Study of Emerging and Re-emerging Pathogens, Rutgers University - New Jersey Medical School, Newark, NJ 07103, USA; Department of Pharmacology, Physiology, and Neuroscience, Rutgers University - New Jersey Medical School, Newark, NJ, 07103, USA
| | - Priscille Brodin
- Univ Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, 1 rue du Professeur Calmette, 59000 Lille, France
| | - Jose Antonio Aínsa
- Departamento de Microbiología, Facultad de Medicina, and BIFI, Universidad de Zaragoza, and IIS-Aragón, 50009 Zaragoza, Spain; CIBER Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Spain
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Anthony Maxwell
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Katarína Mikušová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 84215, Bratislava, Slovakia
| | - Maria Rosalia Pasca
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Sean Ekins
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, NC 27606, USA; Collaborative Drug Discovery, 1633 Bayshore Highway, Suite 342, Burlingame, CA 94403, USA.
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Ekins S, Godbole AA, Kéri G, Orfi L, Pato J, Bhat RS, Verma R, Bradley EK, Nagaraja V. Machine learning and docking models for Mycobacterium tuberculosis topoisomerase I. Tuberculosis (Edinb) 2017; 103:52-60. [PMID: 28237034 DOI: 10.1016/j.tube.2017.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 01/14/2017] [Accepted: 01/18/2017] [Indexed: 11/30/2022]
Abstract
There is a shortage of compounds that are directed towards new targets apart from those targeted by the FDA approved drugs used against Mycobacterium tuberculosis. Topoisomerase I (Mttopo I) is an essential mycobacterial enzyme and a promising target in this regard. However, it suffers from a shortage of known inhibitors. We have previously used computational approaches such as homology modeling and docking to propose 38 FDA approved drugs for testing and identified several active molecules. To follow on from this, we now describe the in vitro testing of a library of 639 compounds. These data were used to create machine learning models for Mttopo I which were further validated. The combined Mttopo I Bayesian model had a 5 fold cross validation receiver operator characteristic of 0.74 and sensitivity, specificity and concordance values above 0.76 and was used to select commercially available compounds for testing in vitro. The recently described crystal structure of Mttopo I was also compared with the previously described homology model and then used to dock the Mttopo I actives norclomipramine and imipramine. In summary, we describe our efforts to identify small molecule inhibitors of Mttopo I using a combination of machine learning modeling and docking studies in conjunction with screening of the selected molecules for enzyme inhibition. We demonstrate the experimental inhibition of Mttopo I by small molecule inhibitors and show that the enzyme can be readily targeted for lead molecule development.
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Affiliation(s)
- Sean Ekins
- Collaborative Drug Discovery, 1633 Bayshore Highway, Suite 342, Burlingame, CA 94403, USA; Collaborations in Chemistry, 5616 Hilltop Needmore Road, Fuquay-Varina, NC 27526, USA.
| | - Adwait Anand Godbole
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - György Kéri
- Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022, Budapest, Hungary; Semmelweis Univ, Dept Med Chem, MTA SE Pathobiochem Res Grp, H-1092, Budapest, Hungary
| | - Lászlo Orfi
- Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022, Budapest, Hungary; Semmelweis Univ, Dept Med Chem, MTA SE Pathobiochem Res Grp, H-1092, Budapest, Hungary
| | - János Pato
- Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022, Budapest, Hungary
| | - Rajeshwari Subray Bhat
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Rinkee Verma
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | | | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India.
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Ghosh S, Padmanabhan B, Godbole AA, Tare P, Ahmed W, Vasu K, China A, Kumar R, Mitra A, Nagaraja V. Transcriptional regulation of topology modulators and transcription regulators of Mycobacterium tuberculosis. Biochem Biophys Res Commun 2016; 475:257-63. [PMID: 27207833 DOI: 10.1016/j.bbrc.2016.05.078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/15/2016] [Indexed: 10/21/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is a formidable pathogen which has the ability to survive the hostile environment of the host by evading the host defense system. The re-configuration of its transcriptional and metabolic process allows the pathogen to confront the adverse environment within the host macrophages. The factors that assist the transcription and modulate the DNA topology would have to play a key role in the regulation of global gene expression of the organism. How transcription of these essential housekeeping genes alters in response to growth conditions and environmental stress has not been addressed together in a set of experimental conditions in Mtb. Now, we have mapped the transcription start sites (TSS) and promoters of several genes that play a central role in the regulation of DNA topology and transcription in Mtb. Using in vivo reporter assays, we validated the activity of the identified promoter elements in different growth conditions. The variation in transcript abundance of these essential genes was also analyzed in growth phase-dependent manner. These data provide the first glimpse into the specific adaptive changes in the expression of genes involved in transcription and DNA topology modulation in Mtb.
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Affiliation(s)
- Soumitra Ghosh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Bhavna Padmanabhan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Adwait Anand Godbole
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Priyanka Tare
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Kommireddy Vasu
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Arnab China
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Rupesh Kumar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Anirban Mitra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India.
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Jepsen ML, Harmsen C, Godbole AA, Nagaraja V, Knudsen BR, Ho YP. Specific detection of the cleavage activity of mycobacterial enzymes using a quantum dot based DNA nanosensor. Nanoscale 2016; 8:358-364. [PMID: 26616006 DOI: 10.1039/c5nr06326d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a quantum dot based DNA nanosensor specifically targeting the cleavage step in the reaction cycle of the essential DNA-modifying enzyme, mycobacterial topoisomerase I. The design takes advantages of the unique photophysical properties of quantum dots to generate visible fluorescence recovery upon specific cleavage by mycobacterial topoisomerase I. This report, for the first time, demonstrates the possibility to quantify the cleavage activity of the mycobacterial enzyme without the pre-processing sample purification or post-processing signal amplification. The cleavage induced signal response has also proven reliable in biological matrices, such as whole cell extracts prepared from Escherichia coli and human Caco-2 cells. It is expected that the assay may contribute to the clinical diagnostics of bacterial diseases, as well as the evaluation of treatment outcomes.
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Affiliation(s)
- Morten Leth Jepsen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus 8000 C, Denmark. and Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark
| | - Charlotte Harmsen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark
| | - Adwait Anand Godbole
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - Birgitta R Knudsen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus 8000 C, Denmark. and Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark
| | - Yi-Ping Ho
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus 8000 C, Denmark. and Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark
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6
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Sipos A, Pató J, Székely R, Hartkoorn RC, Kékesi L, Őrfi L, Szántai-Kis C, Mikušová K, Svetlíková Z, Korduláková J, Nagaraja V, Godbole AA, Bush N, Collin F, Maxwell A, Cole ST, Kéri G. Lead selection and characterization of antitubercular compounds using the Nested Chemical Library. Tuberculosis (Edinb) 2015; 95 Suppl 1:S200-6. [PMID: 25801335 DOI: 10.1016/j.tube.2015.02.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Discovering new drugs to treat tuberculosis more efficiently and to overcome multidrug resistance is a world health priority. To find novel antitubercular agents several approaches have been used in various institutions worldwide, including target-based approaches against several validated mycobacterial enzymes and phenotypic screens. We screened more than 17,000 compounds from Vichem's Nested Chemical Library™ using an integrated strategy involving whole cell-based assays with Corynebacterium glutamicum and Mycobacterium tuberculosis, and target-based assays with protein kinases PknA, PknB and PknG as well as other targets such as PimA and bacterial topoisomerases simultaneously. With the help of the target-based approach we have found very potent hits inhibiting the selected target enzymes, but good minimal inhibitory concentrations (MIC) against M. tuberculosis were not achieved. Focussing on the whole cell-based approach several potent hits were found which displayed minimal inhibitory concentrations (MIC) against M. tuberculosis below 10 μM and were non-mutagenic, non-cytotoxic and the targets of some of the hits were also identified. The most active hits represented various scaffolds. Medicinal chemistry-based lead optimization was performed applying various strategies and, as a consequence, a series of novel potent compounds were synthesized. These efforts resulted in some effective potential antitubercular lead compounds which were confirmed in phenotypic assays.
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Affiliation(s)
- Anna Sipos
- MTA-SE Pathobiochemistry Research Group, Department of Medical Chemistry, Semmelweis University, Tűzoltó u. 37-47, H-1094 Budapest, Hungary; Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022 Budapest, Hungary.
| | - János Pató
- Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022 Budapest, Hungary
| | - Rita Székely
- Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022 Budapest, Hungary; Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Ruben C Hartkoorn
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - László Kékesi
- Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022 Budapest, Hungary
| | - László Őrfi
- Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022 Budapest, Hungary; Semmelweis University, Department of Pharmaceutical Chemistry, Hőgyes Endre u. 9, H-1092 Budapest, Hungary
| | - Csaba Szántai-Kis
- Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022 Budapest, Hungary
| | - Katarína Mikušová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-1, Bratislava, Slovakia
| | - Zuzana Svetlíková
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-1, Bratislava, Slovakia
| | - Jana Korduláková
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-1, Bratislava, Slovakia
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - Adwait Anand Godbole
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - Natassja Bush
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH United Kingdom
| | - Frédéric Collin
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH United Kingdom
| | - Anthony Maxwell
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH United Kingdom
| | - Stewart T Cole
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - György Kéri
- MTA-SE Pathobiochemistry Research Group, Department of Medical Chemistry, Semmelweis University, Tűzoltó u. 37-47, H-1094 Budapest, Hungary; Vichem Chemie Research Ltd., Herman Ottó u. 15, H-1022 Budapest, Hungary.
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Ahmed W, Menon S, Godbole AA, Karthik PVDNB, Nagaraja V. Conditional silencing of topoisomerase I gene of Mycobacterium tuberculosis validates its essentiality for cell survival. FEMS Microbiol Lett 2014; 353:116-23. [PMID: 24593153 DOI: 10.1111/1574-6968.12412] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 02/25/2014] [Accepted: 02/27/2014] [Indexed: 12/19/2022] Open
Abstract
Topoisomerases are an important class of enzymes for regulating the DNA transaction processes. Mycobacterium tuberculosis (Mtb) is one of the most formidable pathogens also posing serious challenges for therapeutic interventions. The organism contains only one type IA topoisomerase (Rv3646c), offering an opportunity to test its potential as a candidate drug target. To validate the essentiality of M. tuberculosis topoisomerase I (TopoI(Mt) ) for bacterial growth and survival, we have generated a conditionally regulated strain of topoI in Mtb. The conditional knockdown mutant exhibited delayed growth on agar plate. In liquid culture, the growth was drastically impaired when TopoI expression was suppressed. Additionally, novobiocin and isoniazid showed enhanced inhibitory potential against the conditional mutant. Analysis of the nucleoid revealed its altered architecture upon TopoI depletion. These studies establish the essentiality of TopoI for the M. tuberculosis growth and open up new avenues for targeting the enzyme.
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Affiliation(s)
- Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
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8
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Godbole AA, Ahmed W, Bhat RS, Bradley EK, Ekins S, Nagaraja V. Inhibition of Mycobacterium tuberculosis topoisomerase I by m-AMSA, a eukaryotic type II topoisomerase poison. Biochem Biophys Res Commun 2014; 446:916-20. [PMID: 24642256 DOI: 10.1016/j.bbrc.2014.03.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/09/2014] [Indexed: 11/26/2022]
Abstract
m-AMSA, an established inhibitor of eukaryotic type II topoisomerases, exerts its cidal effect by binding to the enzyme-DNA complex thus inhibiting the DNA religation step. The molecule and its analogues have been successfully used as chemotherapeutic agents against different forms of cancer. After virtual screening using a homology model of the Mycobacterium tuberculosis topoisomerase I, we identified m-AMSA as a high scoring hit. We demonstrate that m-AMSA can inhibit the DNA relaxation activity of topoisomerase I from M. tuberculosis and Mycobacterium smegmatis. In a whole cell assay, m-AMSA inhibited the growth of both the mycobacteria.
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Affiliation(s)
- Adwait Anand Godbole
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Rajeshwari Subray Bhat
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | | | - Sean Ekins
- Collaborative Drug Discovery, 1633 Bayshore Highway, Suite 342, Burlingame, CA 94403, USA
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
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Abstract
Bacterial DNA topoisomerase I (topoI) catalyzes relaxation of negatively supercoiled DNA. The enzyme alters DNA topology through protein-operated DNA gate, switching between open and closed conformations during its reaction. We describe the mechanism of inhibition of Mycobacterium smegmatis and Mycobacterium tuberculosis topoI by monoclonal antibodies (mAbs) that bind with high affinity and inhibit at 10-50 nM concentration. Unlike other inhibitors of topoisomerases, the mAbs inhibited several steps of relaxation reaction, namely DNA binding, cleavage, strand passage, and enzyme-DNA dissociation. The enhanced religation of the cleaved DNA in presence of the mAb indicated closing of the enzyme DNA gate. The formation of enzyme-DNA heterocatenane in the presence of the mAbs as a result of closing the gate could be inferred by the salt resistance of the complex, visualized by atomic force microscopy and confirmed by fluorescence measurements. Locking the enzyme-DNA complex as a closed clamp restricted the movements of the DNA gate, affecting all of the major steps of the relaxation reaction. Enzyme trapped on DNA in closed clamp conformation formed roadblock for the elongating DNA polymerase. The unusual multistep inhibition of mycobacterial topoisomerases may facilitate lead molecule development, and the mAbs would also serve as valuable tools to probe the enzyme mechanism.
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Affiliation(s)
- Majety Naga Leelaram
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, 560012, India
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Godbole AA, Leelaram MN, Bhat AG, Jain P, Nagaraja V. Characterization of DNA topoisomerase I from Mycobacterium tuberculosis: DNA cleavage and religation properties and inhibition of its activity. Arch Biochem Biophys 2012; 528:197-203. [DOI: 10.1016/j.abb.2012.10.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 10/02/2012] [Accepted: 10/09/2012] [Indexed: 11/30/2022]
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