251
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Vibe CB, Fenaroli F, Pires D, Wilson SR, Bogoeva V, Kalluru R, Speth M, Anes E, Griffiths G, Hildahl J. Thioridazine in PLGA nanoparticles reduces toxicity and improves rifampicin therapy against mycobacterial infection in zebrafish. Nanotoxicology 2015; 10:680-8. [DOI: 10.3109/17435390.2015.1107146] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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252
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Dixit PP, Dixit PP, Thore SN. Hybrid triazoles: Design and synthesis as potential dual inhibitor of growth and efflux inhibition in tuberculosis. Eur J Med Chem 2015; 107:38-47. [PMID: 26562541 DOI: 10.1016/j.ejmech.2015.10.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 10/27/2015] [Accepted: 10/30/2015] [Indexed: 11/19/2022]
Abstract
Efflux inhibition is proven bacterial machinery responsible for removal of bacterial wastage including antibiotics. Recently, efflux inhibitors (EI) have been tested with encouraging results as an adjuvant therapy for treatment of tuberculosis (TB). Although, EI have emerged as innovative approach of treatment for multi drug resistant (MDR) & extensively drug resistant tuberculosis (XDR-TB), toxicity profile limits their wider use. To address this issue, we have attempted synthesizing hybrid molecules those results by combining known EI and triazole. This synthesis was aimed to arrive at structure that possesses pharmacophore from known EI. Synthesized molecules were evaluated as growth inhibitors (GI) and Efflux inhibitor of TB initially against Mycobacterium smegmatis mc(2)155. Pharmacologically active compounds were then tested for their cytotoxicity to further narrow down search. Most active compounds 144, 145, 154 and 163 were then tested for their GEI action against Mycobacterium tuberculosis (Mtb). Synthesized compounds were also tested for their synergistic action with first line and second line anti-TB drugs and ethidium bromide (EtBr). We arrived at compound 135 as most potent dual inhibitor of tuberculosis.
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Affiliation(s)
- Prasad P Dixit
- Department of Chemistry, Vinayakrao Patil Mahavidyalaya, Vaijapur, 423701 Dist Aurangabad, Maharashtra, India
| | - Prashant P Dixit
- Department of Microbiology, Dr. Babasaheb Ambedkar Marathwada University, Sub-Center, Osmanabad, 413501, Dist. Osmanabad, Maharashtra, India
| | - Shivajirao N Thore
- Department of Chemistry, Vinayakrao Patil Mahavidyalaya, Vaijapur, 423701 Dist Aurangabad, Maharashtra, India.
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253
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Development of an Intracellular Screen for New Compounds Able To Inhibit Mycobacterium tuberculosis Growth in Human Macrophages. Antimicrob Agents Chemother 2015; 60:640-5. [PMID: 26503663 DOI: 10.1128/aac.01920-15] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 10/23/2015] [Indexed: 12/19/2022] Open
Abstract
Here we describe the development and validation of an intracellular high-throughput screening assay for finding new antituberculosis compounds active in human macrophages. The assay consists of a luciferase-based primary identification assay, followed by a green fluorescent protein-based secondary profiling assay. Standard tuberculosis drugs and 158 previously recognized active antimycobacterial compounds were used to evaluate assay robustness. Data show that the assay developed is a short and valuable tool for the discovery of new antimycobacterial compounds.
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254
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Pule CM, Sampson SL, Warren RM, Black PA, van Helden PD, Victor TC, Louw GE. Efflux pump inhibitors: targeting mycobacterial efflux systems to enhance TB therapy. J Antimicrob Chemother 2015; 71:17-26. [DOI: 10.1093/jac/dkv316] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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255
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Cronan MR, Rosenberg AF, Oehlers SH, Saelens JW, Sisk DM, Jurcic Smith KL, Lee S, Tobin DM. CLARITY and PACT-based imaging of adult zebrafish and mouse for whole-animal analysis of infections. Dis Model Mech 2015; 8:1643-50. [PMID: 26449262 PMCID: PMC4728314 DOI: 10.1242/dmm.021394] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/23/2015] [Indexed: 12/31/2022] Open
Abstract
Visualization of infection and the associated host response has been challenging in adult vertebrates. Owing to their transparency, zebrafish larvae have been used to directly observe infection in vivo; however, such larvae have not yet developed a functional adaptive immune system. Cells involved in adaptive immunity mature later and have therefore been difficult to access optically in intact animals. Thus, the study of many aspects of vertebrate infection requires dissection of adult organs or ex vivo isolation of immune cells. Recently, CLARITY and PACT (passive clarity technique) methodologies have enabled clearing and direct visualization of dissected organs. Here, we show that these techniques can be applied to image host-pathogen interactions directly in whole animals. CLARITY and PACT-based clearing of whole adult zebrafish and Mycobacterium tuberculosis-infected mouse lungs enables imaging of mycobacterial granulomas deep within tissue to a depth of more than 1 mm. Using established transgenic lines, we were able to image normal and pathogenic structures and their surrounding host context at high resolution. We identified the three-dimensional organization of granuloma-associated angiogenesis, an important feature of mycobacterial infection, and characterized the induction of the cytokine tumor necrosis factor (TNF) within the granuloma using an established fluorescent reporter line. We observed heterogeneity in TNF induction within granuloma macrophages, consistent with an evolving view of the tuberculous granuloma as a non-uniform, heterogeneous structure. Broad application of this technique will enable new understanding of host-pathogen interactions in situ.
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Affiliation(s)
- Mark R Cronan
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Allison F Rosenberg
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Stefan H Oehlers
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Joseph W Saelens
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Dana M Sisk
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kristen L Jurcic Smith
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA Duke Human Vaccine Institute and Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sunhee Lee
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA Duke Human Vaccine Institute and Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - David M Tobin
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
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256
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Abstract
Recent studies are revealing astonishing heterogeneity in host-pathogen interactions occurring simultaneously within the same host tissue. As highlighted in this review, growing knowledge of the in vivo complexity is altering our understanding of infection biology. In particular, pathogen subsets reside in diverse tissue microenvironments and detect and respond to local conditions. The individual pathogen-host encounters have disparate outcomes, depending on differential molecular interactions. As a result, disease progression can result from failure to control individual infection foci, despite successful eradication of others, and antibiotic therapy can be delayed by distinct pre-existing pathogen subsets. Together, these data are unraveling rich biology with implications for infectious disease progression and control.
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Affiliation(s)
- Dirk Bumann
- Focal Area Infection Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland.
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257
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Harvie EA, Huttenlocher A. Neutrophils in host defense: new insights from zebrafish. J Leukoc Biol 2015; 98:523-37. [PMID: 25717145 PMCID: PMC4569048 DOI: 10.1189/jlb.4mr1114-524r] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 01/15/2015] [Accepted: 01/19/2015] [Indexed: 12/11/2022] Open
Abstract
Neutrophils are highly motile phagocytic cells that play a critical role in the immune response to infection. Zebrafish (Danio rerio) are increasingly used to study neutrophil function and host-pathogen interactions. The generation of transgenic zebrafish lines with fluorescently labeled leukocytes has made it possible to visualize the neutrophil response to infection in real time by use of optically transparent zebrafish larvae. In addition, the genetic tractability of zebrafish has allowed for the generation of models of inherited neutrophil disorders. In this review, we discuss several zebrafish models of infectious disease, both in the context of immunocompetent, as well as neutrophil-deficient hosts and how these models have shed light on neutrophil behavior during infection.
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Affiliation(s)
- Elizabeth A Harvie
- *Microbiology Doctoral Training Program, Departments of Medical Microbiology and Immunology and Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Anna Huttenlocher
- *Microbiology Doctoral Training Program, Departments of Medical Microbiology and Immunology and Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin, USA
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258
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Song L, Cui R, Yang Y, Wu X. Role of calcium channels in cellular antituberculosis effects: Potential of voltage-gated calcium-channel blockers in tuberculosis therapy. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2015; 48:471-6. [DOI: 10.1016/j.jmii.2014.08.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/13/2014] [Accepted: 08/07/2014] [Indexed: 11/26/2022]
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259
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Bruhn DF, Scherman MS, Liu J, Scherbakov D, Meibohm B, Böttger EC, Lenaerts AJ, Lee RE. In vitro and in vivo Evaluation of Synergism between Anti-Tubercular Spectinamides and Non-Classical Tuberculosis Antibiotics. Sci Rep 2015; 5:13985. [PMID: 26365087 PMCID: PMC4568539 DOI: 10.1038/srep13985] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 08/12/2015] [Indexed: 12/04/2022] Open
Abstract
Spectinamides are new semi-synthetic spectinomycin derivatives with potent anti-tubercular activity. The reported synergism of the precursor spectinomycin with other antibiotics prompted us to examine whether spectinamides sensitize M. tuberculosis to other antibiotics not traditionally used in the treatment of tuberculosis to potentially expand therapeutic options for MDR/XDR Tuberculosis. Whole cell synergy checkerboard screens were performed using the laboratory strain M. tuberculosis H37Rv, lead spectinamide 1599, and a broad panel of 27 antibiotics. In vitro, 1599 synergized with 11 drugs from 6 antibiotic classes. The observed synergy was tested against clinical isolates confirming synergy with Clarithromycin, Doxycycline and Clindamycin, combinations of which were taken forward for in vivo efficacy determination. Co-administration of 1599 and clarithromycin provided additional bacterial killing in a mouse model of acute tuberculosis infection, but not in a chronic infection model. Further studies indicated that mismatched drug exposure profiles likely permitted induction of phenotypic clarithromycin resistance and subsequent loss of synergism. These studies highlight the importance of validating in vitro synergism and the challenge of matching drug exposures to obtain a synergistic outcome in vivo. Results from this study indicate that a 1599 clarithromycin combination is potentially viable, providing the drug exposures can be carefully monitored.
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Affiliation(s)
- David F. Bruhn
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Michael S. Scherman
- Mycobacterial Research Laboratories, Department of Microbiology, Colorado State University, Fort Collins, Colorado, USA
| | - Jiuyu Liu
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Dimitri Scherbakov
- Institut für Medizinische Mikrobiologie, Nationales Zentrum für Mykobakterien, Universität Zürich, Zürich, Switzerland
| | - Bernd Meibohm
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Erik C. Böttger
- Institut für Medizinische Mikrobiologie, Nationales Zentrum für Mykobakterien, Universität Zürich, Zürich, Switzerland
| | - Anne J. Lenaerts
- Mycobacterial Research Laboratories, Department of Microbiology, Colorado State University, Fort Collins, Colorado, USA
| | - Richard E. Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
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260
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Bernut A, Dupont C, Sahuquet A, Herrmann JL, Lutfalla G, Kremer L. Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos. J Vis Exp 2015. [PMID: 26382225 DOI: 10.3791/53130] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Zebrafish (Danio rerio) embryos are increasingly used as an infection model to study the function of the vertebrate innate immune system in host-pathogen interactions. The ease of obtaining large numbers of embryos, their accessibility due to external development, their optical transparency as well as the availability of a wide panoply of genetic/immunological tools and transgenic reporter line collections, contribute to the versatility of this model. In this respect, the present manuscript describes the use of zebrafish as an in vivo model system to investigate the chronology of Mycobacterium abscessus infection. This human pathogen can exist either as smooth (S) or rough (R) variants, depending on cell wall composition, and their respective virulence can be imaged and compared in zebrafish embryos and larvae. Micro-injection of either S or R fluorescent variants directly in the blood circulation via the caudal vein, leads to chronic or acute/lethal infections, respectively. This biological system allows high resolution visualization and analysis of the role of mycobacterial cording in promoting abscess formation. In addition, the use of fluorescent bacteria along with transgenic zebrafish lines harbouring fluorescent macrophages produces a unique opportunity for multi-color imaging of the host-pathogen interactions. This article describes detailed protocols for the preparation of homogenous M. abscessus inoculum and for intravenous injection of zebrafish embryos for subsequent fluorescence imaging of the interaction with macrophages. These techniques open the avenue to future investigations involving mutants defective in cord formation and are dedicated to understand how this impacts on M. abscessus pathogenicity in a whole vertebrate.
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Affiliation(s)
- Audrey Bernut
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS, UMR 535, Université Montpellier; Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, CNRS, FRE 3689, Université Montpellier
| | - Christian Dupont
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS, UMR 535, Université Montpellier; Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, CNRS, FRE 3689, Université Montpellier
| | - Alain Sahuquet
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS, UMR 535, Université Montpellier
| | - Jean-Louis Herrmann
- Unité de Formation et de Recherche des Sciences de la Santé, EA3647-EPIM, Université Versailles St Quentin
| | - Georges Lutfalla
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS, UMR 535, Université Montpellier;
| | - Laurent Kremer
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS, UMR 535, Université Montpellier; Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, CNRS, FRE 3689, Université Montpellier;
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261
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Stationary-Phase Persisters to Ofloxacin Sustain DNA Damage and Require Repair Systems Only during Recovery. mBio 2015; 6:e00731-15. [PMID: 26330511 PMCID: PMC4556807 DOI: 10.1128/mbio.00731-15] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Chronic infections are a serious health care problem, and bacterial persisters have been implicated in infection reoccurrence. Progress toward finding antipersister therapies has been slow, in part because of knowledge gaps regarding the physiology of these rare phenotypic variants. Evidence shows that growth status is important for survival, as nongrowing cultures can have 100-fold more persisters than growing populations. However, additional factors are clearly important, as persisters remain rare even in nongrowing populations. What features, beyond growth inhibition, allow persisters to survive antibiotic stress while the majority of their kin succumb to it remains an open question. To investigate this, we used stationary phase as a model nongrowing environment to study Escherichia coli persistence to ofloxacin. Given that the prevailing model of persistence attributes survival to transient dormancy and antibiotic target inactivity, we anticipated that persisters would suffer less damage than their dying kin. However, using genetic mutants, flow cytometry, fluorescence-activated cell sorting, and persistence assays, we discovered that nongrowing ofloxacin persisters experience antibiotic-induced damage that is indistinguishable from that of nonpersisters. Consistent with this, we found that these persisters required DNA repair for survival and that repair machinery was unnecessary until the posttreatment recovery period (after ofloxacin removal). These findings suggest that persistence to ofloxacin is not engendered solely by reduced antibiotic target corruption, demonstrate that what happens following antibiotic stress can be critical to the persistence phenotype, and support the notion that inhibition of DNA damage repair systems could be an effective strategy to eliminate fluoroquinolone persisters. In the absence of resistant mutants, infection reoccurrences can still occur because of persisters, rare bacterial cells that survive antibiotic treatments to repopulate infection sites. Persister survival is attributed to a transient state of dormancy in which a cell’s growth and metabolism are significantly reduced and many essential processes are thought to be inactive. Thus, dormancy is believed to protect persisters from antibiotic-induced damage and death. In this work, we show that in nongrowing populations, persisters to ofloxacin experience the same level of antibiotic-induced damage as cells that succumb to the treatment and that their survival critically depends on repair of this damage after the conclusion of treatment. These findings reveal that persistence to ofloxacin is not engendered solely by reduced antibiotic target corruption and highlight that processes following antibiotic stress are important to survival. We hypothesize that effective antipersister therapies may be developed on the basis of this knowledge.
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262
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Protection and pathology in TB: learning from the zebrafish model. Semin Immunopathol 2015; 38:261-73. [PMID: 26324465 PMCID: PMC4779130 DOI: 10.1007/s00281-015-0522-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/11/2015] [Indexed: 12/14/2022]
Abstract
Zebrafish has earned its place among animal models of tuberculosis. Its natural pathogen, Mycobacterium marinum, shares major virulence factors with the human pathogen Mycobacterium tuberculosis. In adult zebrafish, which possess recombination-activated adaptive immunity, it can cause acute infection or a chronic progressive disease with containment of mycobacteria in well-structured, caseating granulomas. In addition, a low-dose model that closely mimics human latent infection has recently been developed. These models are used alongside infection of optically transparent zebrafish embryos and larvae that rely on innate immunity and permit non-invasive visualization of the early stages of developing granulomas that are inaccessible in other animal models. By microinjecting mycobacteria intravenously or into different tissues, systemic and localized infections can be induced, each useful for studying particular aspects of early pathogenesis, such as phagocyte recruitment, granuloma expansion and maintenance, vascularization of granulomas, and the phagocyte-mediated dissemination of mycobacteria. This has contributed to new insights into the mycobacteria-driven mechanisms that promote granuloma formation, the double-edged role of inflammation, the mechanisms of macrophage cell death that favor disease progression, and the host-protective role of autophagy. As a result, zebrafish models are now increasingly used to explore strategies for adjunctive therapy of tuberculosis with host-directed drugs.
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263
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Luthuli BB, Purdy GE, Balagaddé FK. Confinement-Induced Drug-Tolerance in Mycobacteria Mediated by an Efflux Mechanism. PLoS One 2015; 10:e0136231. [PMID: 26295942 PMCID: PMC4546595 DOI: 10.1371/journal.pone.0136231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/30/2015] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis (TB) is the world's deadliest curable disease, responsible for an estimated 1.5 million deaths annually. A considerable challenge in controlling this disease is the prolonged multidrug chemotherapy (6 to 9 months) required to overcome drug-tolerant mycobacteria that persist in human tissues, although the same drugs can sterilize genetically identical mycobacteria growing in axenic culture within days. An essential component of TB infection involves intracellular Mycobacterium tuberculosis bacteria that multiply within macrophages and are significantly more tolerant to antibiotics compared to extracellular mycobacteria. To investigate this aspect of human TB, we created a physical cell culture system that mimics confinement of replicating mycobacteria, such as in a macrophage during infection. Using this system, we uncovered an epigenetic drug-tolerance phenotype that appears when mycobacteria are cultured in space-confined bioreactors and disappears in larger volume growth contexts. Efflux mechanisms that are induced in space-confined growth environments contribute to this drug-tolerance phenotype. Therefore, macrophage-induced drug tolerance by mycobacteria may be an effect of confined growth among other macrophage-specific mechanisms.
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Affiliation(s)
- Brilliant B. Luthuli
- KwaZulu-Natal Research Institute for Tuberculosis and HIV, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, 4001, South Africa
| | - Georgiana E. Purdy
- Dept. of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 S. W. Sam Jackson Park Rd., Mail Code L220, Portland, OR, 97239, United States of America
| | - Frederick K. Balagaddé
- KwaZulu-Natal Research Institute for Tuberculosis and HIV, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, 4001, South Africa
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264
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Du D, van Veen HW, Murakami S, Pos KM, Luisi BF. Structure, mechanism and cooperation of bacterial multidrug transporters. Curr Opin Struct Biol 2015; 33:76-91. [PMID: 26282926 DOI: 10.1016/j.sbi.2015.07.015] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/29/2015] [Accepted: 07/24/2015] [Indexed: 12/13/2022]
Abstract
Cells from all domains of life encode energy-dependent trans-membrane transporters that can expel harmful substances including clinically applied therapeutic agents. As a collective body, these transporters perform as a super-system that confers tolerance to an enormous range of harmful compounds and consequently aid survival in hazardous environments. In the Gram-negative bacteria, some of these transporters serve as energy-transducing components of tripartite assemblies that actively efflux drugs and other harmful compounds, as well as deliver virulence agents across the entire cell envelope. We draw together recent structural and functional data to present the current models for the transport mechanisms for the main classes of multi-drug transporters and their higher-order assemblies.
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Affiliation(s)
- Dijun Du
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Hendrik W van Veen
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Satoshi Murakami
- Division of Structure and Function of Biomolecules, Department of Life Science, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Klaas M Pos
- Institute of Biochemistry, Goethe Universität Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK.
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265
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Pieroni M, Machado D, Azzali E, Santos Costa S, Couto I, Costantino G, Viveiros M. Rational Design and Synthesis of Thioridazine Analogues as Enhancers of the Antituberculosis Therapy. J Med Chem 2015. [PMID: 26197353 DOI: 10.1021/acs.jmedchem.5b00428] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tuberculosis, caused by Mycobacterium tuberculosis, is still one of the leading infectious diseases globally. Therefore, novel approaches are needed to face this disease. Efflux pumps are known to contribute to the emergence of M. tuberculosis drug resistance. Thioridazine has shown good anti-TB properties both in vitro and in vivo, likely due to its capacity to inhibit efflux mechanisms. Here we report the design and synthesis of a number of putative efflux inhibitors inspired by the structure of thioridazine. Compounds were evaluated for their in vitro and ex vivo activity against M. tuberculosis H37Rv. Compared to the parent molecule, some of the compounds synthesized showed higher efflux inhibitory capacity, less cytotoxicity, and a remarkable synergistic effect with anti-TB drugs both in vitro and in human macrophages, demonstrating their potential to be used as coadjuvants for the treatment of tuberculosis.
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Affiliation(s)
- Marco Pieroni
- †P4T Group, Dipartimento di Farmacia, University of Parma, Parco Area delle Scienze 27/A, Parma, 43124, Italy
| | - Diana Machado
- ‡Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa (IHMT, UNL), Rua da Junqueira, 100, 1349-008 Lisbon, Portugal
| | - Elisa Azzali
- †P4T Group, Dipartimento di Farmacia, University of Parma, Parco Area delle Scienze 27/A, Parma, 43124, Italy
| | - Sofia Santos Costa
- ‡Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa (IHMT, UNL), Rua da Junqueira, 100, 1349-008 Lisbon, Portugal
| | - Isabel Couto
- ‡Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa (IHMT, UNL), Rua da Junqueira, 100, 1349-008 Lisbon, Portugal
| | - Gabriele Costantino
- †P4T Group, Dipartimento di Farmacia, University of Parma, Parco Area delle Scienze 27/A, Parma, 43124, Italy
| | - Miguel Viveiros
- ‡Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa (IHMT, UNL), Rua da Junqueira, 100, 1349-008 Lisbon, Portugal
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266
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Srikrishna G, Gupta S, Dooley KE, Bishai WR. Can the addition of verapamil to bedaquiline-containing regimens improve tuberculosis treatment outcomes? A novel approach to optimizing TB treatment. Future Microbiol 2015; 10:1257-60. [PMID: 26226503 DOI: 10.2217/fmb.15.56] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Geetha Srikrishna
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Room 108, 1550 Orleans St, Baltimore, MD 21231, USA.,Division of Infectious Diseases, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Shashank Gupta
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Room 108, 1550 Orleans St, Baltimore, MD 21231, USA.,Division of Infectious Diseases, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Kelly E Dooley
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Room 108, 1550 Orleans St, Baltimore, MD 21231, USA.,Division of Infectious Diseases, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.,Division of Clinical Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - William R Bishai
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Room 108, 1550 Orleans St, Baltimore, MD 21231, USA.,Division of Infectious Diseases, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
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267
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Gumbo T, Pasipanodya JG, Nuermberger E, Romero K, Hanna D. Correlations Between the Hollow Fiber Model of Tuberculosis and Therapeutic Events in Tuberculosis Patients: Learn and Confirm. Clin Infect Dis 2015. [DOI: 10.1093/cid/civ426] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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268
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Hodzic E. Lyme Borreliosis: Is there a preexisting (natural) variation in antimicrobial susceptibility among Borrelia burgdorferi strains? Bosn J Basic Med Sci 2015; 15:1-13. [PMID: 26295288 DOI: 10.17305/bjbms.2015.594] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 06/29/2015] [Accepted: 06/30/2015] [Indexed: 12/31/2022] Open
Abstract
The development of antibiotics changed the world of medicine and has saved countless human and animal lives. Bacterial resistance/tolerance to antibiotics have spread silently across the world and has emerged as a major public health concern. The recent emergence of pan-resistant bacteria can overcome virtually any antibiotic and poses a major problem for their successful control. Selection for antibiotic resistance may take place where an antibiotic is present: in the skin, gut, and other tissues of humans and animals and in the environment. Borrelia burgdorferi, the etiological agents of Lyme borreliosis, evades host immunity and establishes persistent infections in its mammalian hosts. The persistent infection poses a challenge to the effective antibiotic treatment, as demonstrated in various animal models. An increasingly heterogeneous subpopulation of replicatively attenuated spirochetes arises following treatment, and these persistent antimicrobial tolerant/resistant spirochetes are non-cultivable. The non-cultivable spirochetes resurge in multiple tissues at 12 months after treatment, with B. burgdorferi-specific DNA copy levels nearly equivalent to those found in shame-treated experimental animals. These attenuated spirochetes remain viable, but divide slowly, thereby being tolerant to antibiotics. Despite the continued non-cultivable state, RNA transcription of multiple B. burgdorferi genes was detected in host tissues, spirochetes were acquired by xenodiagnostic ticks, and spirochetal forms could be visualized within ticks and mouse tissues. A number of host cytokines were up- or down-regulated in tissues of both shame- and antibiotic-treated mice in the absence of histopathology, indicating a lack of host response to the presence of antimicrobial tolerant/resistant spirochetes.
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Affiliation(s)
- Emir Hodzic
- Real-Time PCR Research & Diagnostics Core Facility, School of Veterinary Medicine, University of California, Davis.
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269
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Bernut A, Lutfalla G, Kremer L. [Looking through zebrafish to study host-pathogen interactions]. Med Sci (Paris) 2015; 31:638-46. [PMID: 26152168 DOI: 10.1051/medsci/20153106017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The zebrafish offers many advantages that motivated and validated its use to study the virulence of numerous human pathogens, including viruses, bacteria and fungi. Its immune system is homologous to the one of mammals. The optical transparency of zebrafish embryos allows non-invasive and real-time monitoring of the infection processes through the use of imaging techniques. The zebrafish is therefore a useful and powerful model to study host-pathogen interactions at a cellular level. It may be used to describe pathophysiological events and subversion mechanisms that are specific to each pathogen. In addition to increasing our understanding of the host immune defense, this model is of high potential for medical application, being particularly amenable to high-throughput screening for the discovery of new anti-infective molecules.
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Affiliation(s)
- Audrey Bernut
- Centre d'étude des pathogènes pour la biotechnologie et la santé (CPBS), CNRS FRE3689, 1919, route de Mende, 34293 Montpellier Cedex 05, France
| | - Georges Lutfalla
- Laboratoire de dynamique des interactions membranaires normales et pathologiques, CNRS UMR5235, université de Montpellier, place Eugène Bataillon, Montpellier, France
| | - Laurent Kremer
- Centre d'étude des pathogènes pour la biotechnologie et la santé (CPBS), CNRS FRE3689, 1919, route de Mende, 34293 Montpellier Cedex 05, France - Inserm, CPBS, 1919, route de Mende, 34293 Montpellier Cedex 05, France
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270
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Tyagi P, Dharmaraja AT, Bhaskar A, Chakrapani H, Singh A. Mycobacterium tuberculosis has diminished capacity to counteract redox stress induced by elevated levels of endogenous superoxide. Free Radic Biol Med 2015; 84:344-354. [PMID: 25819161 PMCID: PMC4459714 DOI: 10.1016/j.freeradbiomed.2015.03.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 03/09/2015] [Accepted: 03/10/2015] [Indexed: 12/20/2022]
Abstract
Mycobacterium tuberculosis (Mtb) has evolved protective and detoxification mechanisms to maintain cytoplasmic redox balance in response to exogenous oxidative stress encountered inside host phagocytes. In contrast, little is known about the dynamic response of this pathogen to endogenous oxidative stress generated within Mtb. Using a noninvasive and specific biosensor of cytoplasmic redox state of Mtb, we for first time discovered a surprisingly high sensitivity of this pathogen to perturbation in redox homeostasis induced by elevated endogenous reactive oxygen species (ROS). We synthesized a series of hydroquinone-based small molecule ROS generators and found that ATD-3169 permeated mycobacteria to reliably enhance endogenous ROS including superoxide radicals. When Mtb strains including multidrug-resistant (MDR) and extensively drug-resistant (XDR) patient isolates were exposed to this compound, a dose-dependent, long-lasting, and irreversible oxidative shift in intramycobacterial redox potential was detected. Dynamic redox potential measurements revealed that Mtb had diminished capacity to restore cytoplasmic redox balance in comparison with Mycobacterium smegmatis (Msm), a fast growing nonpathogenic mycobacterial species. Accordingly, Mtb strains were extremely susceptible to inhibition by ATD-3169 but not Msm, suggesting a functional linkage between dynamic redox changes and survival. Microarray analysis showed major realignment of pathways involved in redox homeostasis, central metabolism, DNA repair, and cell wall lipid biosynthesis in response to ATD-3169, all consistent with enhanced endogenous ROS contributing to lethality induced by this compound. This work provides empirical evidence that the cytoplasmic redox poise of Mtb is uniquely sensitive to manipulation in steady-state endogenous ROS levels, thus revealing the importance of targeting intramycobacterial redox metabolism for controlling TB infection.
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Affiliation(s)
- Priyanka Tyagi
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research (CIDR), Indian Institute of Science, Bangalore-12, India; International Centre for Genetic Engineering and Biotechnology, New Delhi 67, India
| | - Allimuthu T Dharmaraja
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 08, India
| | - Ashima Bhaskar
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research (CIDR), Indian Institute of Science, Bangalore-12, India
| | - Harinath Chakrapani
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 08, India.
| | - Amit Singh
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research (CIDR), Indian Institute of Science, Bangalore-12, India.
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271
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Myllymäki H, Niskanen M, Oksanen KE, Rämet M. Animal models in tuberculosis research - where is the beef? Expert Opin Drug Discov 2015; 10:871-83. [PMID: 26073097 DOI: 10.1517/17460441.2015.1049529] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
INTRODUCTION Tuberculosis (TB) is a major global health problem, and new drugs and vaccines are urgently needed. As clinical trials in humans require tremendous resources, preclinical drug and vaccine development largely relies on valid animal models that recapitulate the pathology of human disease and the immune responses of the host as closely as possible. AREAS COVERED This review describes the animal models used in TB research, the most widely used being mice, guinea pigs and nonhuman primates. In addition, rabbits and cattle provide models with a disease pathology resembling that of humans. Invertebrate models, including the fruit fly and the Dictyostelium amoeba, have also been used to study mycobacterial infections. Recently, the zebrafish has emerged as a promising model for studying mycobacterial infections. The zebrafish model also facilitates the large-scale screening of drug and vaccine candidates. EXPERT OPINION Animal models are needed for TB research and provide valuable information on the mechanisms of the disease and on ways of preventing it. However, the data obtained in animal studies need to be carefully interpreted and evaluated before making assumptions concerning humans. With an increasing understanding of disease mechanisms, animal models can be further improved to best serve research goals.
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Affiliation(s)
- Henna Myllymäki
- BioMediTech, University of Tampere , FIN 33014 Tampere , Finland
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272
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Rayasam GV, Balganesh TS. Exploring the potential of adjunct therapy in tuberculosis. Trends Pharmacol Sci 2015; 36:506-13. [PMID: 26073420 DOI: 10.1016/j.tips.2015.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/15/2015] [Accepted: 05/15/2015] [Indexed: 01/02/2023]
Abstract
A critical unmet need for treatment of drug-resistant tuberculosis (TB) is to find novel therapies that are efficacious, safe, and shorten the duration of treatment. Drug discovery approaches for TB primarily target essential genes of the pathogen Mycobacterium tuberculosis (Mtb) but novel strategies such as host-directed therapies and nonmicrobicidal targets are necessary to bring about a paradigm shift in treatment. Drugs targeting the host pathways and nonmicrobicidal proteins can be used only in conjunction with existing drugs as adjunct therapies. Significantly, host-directed adjunct therapies have the potential to decrease duration of treatment, as they are less prone to drug resistance, target the immune responses, and act via novel mechanism of action. Recent advances in targeting host-pathogen interactions have implicated pathways such as eicosanoid regulation and angiogenesis. Furthermore, several approved drugs such as metformin and verapamil have been identified that appear suitable for repurposing for the treatment of TB. These findings and the challenges in the area of host- and/or pathogen-directed adjunct therapies and their implications for TB therapy are discussed.
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Affiliation(s)
- Geetha Vani Rayasam
- CSIR-Open Source Drug Discovery (OSDD) Unit, Council for Scientific and Industrial Research, Anusandhan Bhavan, 2 Rafi Marg, New Delhi, India.
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273
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Mycobacterium-Host Cell Relationships in Granulomatous Lesions in a Mouse Model of Latent Tuberculous Infection. BIOMED RESEARCH INTERNATIONAL 2015; 2015:948131. [PMID: 26064970 PMCID: PMC4433666 DOI: 10.1155/2015/948131] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 10/21/2014] [Indexed: 12/24/2022]
Abstract
Tuberculosis (TB) is a dangerous infectious disease characterized by a tight interplay between mycobacteria and host cells in granulomatous lesions (granulomas) during the latent, asymptomatic stage of infection. Mycobacterium-host cell relationships were analyzed in granulomas obtained from various organs of BALB/c mice with chronic TB infection caused by in vivo exposure to the Bacillus Calmette-Guérin (BCG) vaccine. Acid-fast BCG-mycobacteria were found to be morphologically and functionally heterogeneous (in size, shape, and replication rates in colonies) in granuloma macrophages, dendritic cells, and multinucleate Langhans giant cells. Cord formation by BCG-mycobacteria in granuloma cells has been observed. Granuloma macrophages retained their ability to ingest damaged lymphocytes and thrombocytes in the phagosomes; however, their ability to destroy BCG-mycobacteria contained in these cells was compromised. No colocalization of BCG-mycobacteria and the LysoTracker dye was observed in the mouse cells. Various relationships between granuloma cells and BCG-mycobacteria were observed in different mice belonging to the same line. Several mice totally eliminated mycobacterial infection. Granulomas in the other mice had mycobacteria actively replicating in cells of different types and forming cords, which is an indicator of mycobacterial virulence and, probably, a marker of the activation of tuberculous infection in animals.
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274
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Antony C, Mehto S, Tiwari BK, Singh Y, Natarajan K. Regulation of L-type Voltage Gated Calcium Channel CACNA1S in Macrophages upon Mycobacterium tuberculosis Infection. PLoS One 2015; 10:e0124263. [PMID: 25915405 PMCID: PMC4411123 DOI: 10.1371/journal.pone.0124263] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 03/11/2015] [Indexed: 01/17/2023] Open
Abstract
We demonstrated earlier the inhibitory role played by Voltage Gated Calcium Channels (VGCCs) in regulating Mycobacterium tuberculosis (M. tb) survival and pathogenesis. In this report, we investigated mechanisms and key players that regulate the surface expression of VGCC-CACNA1S by Rv2463 and M. tb infection in macrophages. Our earlier work identified Rv2463 to be expressed at early times post infection in macrophages that induced suppressor responses to dendritic cells and macrophages. Our results in this study demonstrate a role of MyD88 independent TLR pathway in mediating CACNA1S expression. Dissecting the role for second messengers, we show that calcium homeostasis plays a key role in CACNA1S expression during M. tb infection. Using siRNAs against molecular sensors of calcium regulation, we show an involvement of ER associated Stromal Interaction Molecules 1 and 2 (STIM1 and STIM2), and transcription factor pCREB, towards CACNA1S expression that also involved the MyD88 independent pathway. Interestingly, reactive oxygen species played a negative role in M. tb mediated CACNA1S expression. Further, a cross-regulation of ROS and pCREB was noted that governed CACNA1S expression. Characterizing the mechanisms governing CACNA1S expression would improve our understanding of the regulation of VGCC expression and its role in M. tb pathogenesis during M. tb infection.
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Affiliation(s)
- Cecil Antony
- Infectious Disease Immunology Lab, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, Delhi, 110007, India
- * E-mail: (CA); (KN)
| | - Subhash Mehto
- Infectious Disease Immunology Lab, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, Delhi, 110007, India
| | - Brijendra K. Tiwari
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
| | - Yogendra Singh
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi, 110007, India
| | - Krishnamurthy Natarajan
- Infectious Disease Immunology Lab, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, Delhi, 110007, India
- * E-mail: (CA); (KN)
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275
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Latent tuberculosis infection: myths, models, and molecular mechanisms. Microbiol Mol Biol Rev 2015; 78:343-71. [PMID: 25184558 DOI: 10.1128/mmbr.00010-14] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The aim of this review is to present the current state of knowledge on human latent tuberculosis infection (LTBI) based on clinical studies and observations, as well as experimental in vitro and animal models. Several key terms are defined, including "latency," "persistence," "dormancy," and "antibiotic tolerance." Dogmas prevalent in the field are critically examined based on available clinical and experimental data, including the long-held beliefs that infection is either latent or active, that LTBI represents a small population of nonreplicating, "dormant" bacilli, and that caseous granulomas are the haven for LTBI. The role of host factors, such as CD4(+) and CD8(+) T cells, T regulatory cells, tumor necrosis factor alpha (TNF-α), and gamma interferon (IFN-γ), in controlling TB infection is discussed. We also highlight microbial regulatory and metabolic pathways implicated in bacillary growth restriction and antibiotic tolerance under various physiologically relevant conditions. Finally, we pose several clinically important questions, which remain unanswered and will serve to stimulate future research on LTBI.
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276
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Zhang Z, Yan J, Xu K, Ji Z, Li L. Tetrandrine reverses drug resistance in isoniazid and ethambutol dual drug-resistant Mycobacterium tuberculosis clinical isolates. BMC Infect Dis 2015; 15:153. [PMID: 25887373 PMCID: PMC4417324 DOI: 10.1186/s12879-015-0905-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 03/13/2015] [Indexed: 02/04/2023] Open
Abstract
Background Tetrandrine is a natural chemical product purified from fourstamen stephania root which recently has been shown to act similarly as synthesized drug efflux pump inhibitor verapamil. The aim of the study is to examine whether tetrandrine could potentiate anti-tubercular drugs to which Mycobacterium tuberculosis (MTB) has turned resistant via efflux mechanisms. Methods We screened 200 MTB clinical isolates using drug sensitivity test to look for those who have turned resistant to the drugs most probably due to efflux mechanisms. We found 29 isoniazid (INH) and ethambutol (EMB) - dual resistant (IEDR) strains. Then we tested if treatment with tetrandrine or verapamil could reverse drug resistance to INH and/or EMB in IEDR isolates. Results There is a parallel resistance among EMB- and INH-resistant strains in the tested clinical isolates. Among INH-resistant strains, 65% was also EMB-resistant. This suggests an involvement of efflux mechanisms which can lead to dual drug resistance in IEDR clinical isolates. Similar to a synthesized efflux pump inhibitor verapamil, tetrandrine treatment together with INH or EMB brought down the MICs from the clinical level of drug resistance to the sensitive range of both drugs. The effective rate reached 82% among IEDR clinical isolates. Conclusions Combinational application of tetrandrine with INH or EMB increased drug efficacy. Drugs like tetrandrine may help to reduce drug dosage thus alleviate side effects.
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Affiliation(s)
- Zhe Zhang
- Research Center of Infection and Immunity, Department of Microbiology and Parasitology, School of Basic Medical Sciences, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Jie Yan
- Research Center of Infection and Immunity, Department of Microbiology and Parasitology, School of Basic Medical Sciences, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Kaijin Xu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of School of Medicine, Zhejiang University, 15th floor, Building 6A, No. 79 Qingchun Road, Shangcheng District, Hangzhou, 310003, Zhejiang Province, China.
| | - Zhongkang Ji
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of School of Medicine, Zhejiang University, 15th floor, Building 6A, No. 79 Qingchun Road, Shangcheng District, Hangzhou, 310003, Zhejiang Province, China.
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of School of Medicine, Zhejiang University, 15th floor, Building 6A, No. 79 Qingchun Road, Shangcheng District, Hangzhou, 310003, Zhejiang Province, China.
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277
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Walter ND, Dolganov GM, Garcia BJ, Worodria W, Andama A, Musisi E, Ayakaka I, Van TT, Voskuil MI, de Jong BC, Davidson RM, Fingerlin TE, Kechris K, Palmer C, Nahid P, Daley CL, Geraci M, Huang L, Cattamanchi A, Strong M, Schoolnik GK, Davis JL. Transcriptional Adaptation of Drug-tolerant Mycobacterium tuberculosis During Treatment of Human Tuberculosis. J Infect Dis 2015; 212:990-8. [PMID: 25762787 DOI: 10.1093/infdis/jiv149] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 03/02/2015] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Treatment initiation rapidly kills most drug-susceptible Mycobacterium tuberculosis, but a bacterial subpopulation tolerates prolonged drug exposure. We evaluated drug-tolerant bacilli in human sputum by comparing messenger RNA (mRNA) expression of drug-tolerant bacilli that survive the early bactericidal phase with treatment-naive bacilli. METHODS M. tuberculosis gene expression was quantified via reverse-transcription polymerase chain reaction in serial sputa from 17 Ugandans treated for drug-susceptible pulmonary tuberculosis. RESULTS Within 4 days, bacterial mRNA abundance declined >98%, indicating rapid killing. Thereafter, the rate of decline slowed >94%, indicating drug tolerance. After 14 days, 16S ribosomal RNA transcripts/genome declined 96%, indicating slow growth. Drug-tolerant bacilli displayed marked downregulation of genes associated with growth, metabolism, and lipid synthesis and upregulation in stress responses and key regulatory categories-including stress-associated sigma factors, transcription factors, and toxin-antitoxin genes. Drug efflux pumps were upregulated. The isoniazid stress signature was induced by initial drug exposure, then disappeared after 4 days. CONCLUSIONS Transcriptional patterns suggest that drug-tolerant bacilli in sputum are in a slow-growing, metabolically and synthetically downregulated state. Absence of the isoniazid stress signature in drug-tolerant bacilli indicates that physiological state influences drug responsiveness in vivo. These results identify novel drug targets that should aid in development of novel shorter tuberculosis treatment regimens.
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Affiliation(s)
- Nicholas D Walter
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora Pulmonary Division, Denver Veterans Administration Medical Center, Colorado
| | - Gregory M Dolganov
- Department of Microbiology and Immunology, Stanford University, California
| | - Benjamin J Garcia
- Integrated Center for Genes, Environment, and Health, National Jewish Health, Denver Computational Bioscience Program, University of Colorado Denver, Aurora
| | - William Worodria
- Makerere University-University of California, San Francisco Research Collaboration, Kampala, Uganda
| | - Alfred Andama
- Makerere University-University of California, San Francisco Research Collaboration, Kampala, Uganda
| | - Emmanuel Musisi
- Makerere University-University of California, San Francisco Research Collaboration, Kampala, Uganda
| | - Irene Ayakaka
- Makerere University-University of California, San Francisco Research Collaboration, Kampala, Uganda
| | - Tran T Van
- Department of Microbiology and Immunology, Stanford University, California
| | - Martin I Voskuil
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora
| | | | - Rebecca M Davidson
- Integrated Center for Genes, Environment, and Health, National Jewish Health, Denver
| | - Tasha E Fingerlin
- Department of Epidemiology and Biostatistics Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora
| | - Katerina Kechris
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora
| | - Claire Palmer
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora
| | - Payam Nahid
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco
| | - Charles L Daley
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora Division of Mycobacterial and Respiratory Infections, National Jewish Health, Denver, Colorado
| | - Mark Geraci
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora
| | - Laurence Huang
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco HIV/AIDS Division, University of California San Francisco
| | - Adithya Cattamanchi
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco
| | - Michael Strong
- Integrated Center for Genes, Environment, and Health, National Jewish Health, Denver
| | - Gary K Schoolnik
- Department of Microbiology and Immunology, Stanford University, California
| | - John Lucian Davis
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco
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278
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Torraca V, Masud S, Spaink HP, Meijer AH. Macrophage-pathogen interactions in infectious diseases: new therapeutic insights from the zebrafish host model. Dis Model Mech 2015; 7:785-97. [PMID: 24973749 PMCID: PMC4073269 DOI: 10.1242/dmm.015594] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Studying macrophage biology in the context of a whole living organism provides unique possibilities to understand the contribution of this extremely dynamic cell subset in the reaction to infections, and has revealed the relevance of cellular and molecular processes that are fundamental to the cell-mediated innate immune response. In particular, various recently established zebrafish infectious disease models are contributing substantially to our understanding of the mechanisms by which different pathogens interact with macrophages and evade host innate immunity. Transgenic zebrafish lines with fluorescently labeled macrophages and other leukocyte populations enable non-invasive imaging at the optically transparent early life stages. Furthermore, there is a continuously expanding availability of vital reporters for subcellular compartments and for probing activation of immune defense mechanisms. These are powerful tools to visualize the activity of phagocytic cells in real time and shed light on the intriguing paradoxical roles of these cells in both limiting infection and supporting the dissemination of intracellular pathogens. This Review will discuss how several bacterial and fungal infection models in zebrafish embryos have led to new insights into the dynamic molecular and cellular mechanisms at play when pathogens encounter host macrophages. We also describe how these insights are inspiring novel therapeutic strategies for infectious disease treatment.
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Affiliation(s)
- Vincenzo Torraca
- Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Samrah Masud
- Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Herman P Spaink
- Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Annemarie H Meijer
- Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
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279
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Ordas A, Raterink RJ, Cunningham F, Jansen HJ, Wiweger MI, Jong-Raadsen S, Bos S, Bates RH, Barros D, Meijer AH, Vreeken RJ, Ballell-Pages L, Dirks RP, Hankemeier T, Spaink HP. Testing tuberculosis drug efficacy in a zebrafish high-throughput translational medicine screen. Antimicrob Agents Chemother 2015; 59:753-62. [PMID: 25385118 PMCID: PMC4335901 DOI: 10.1128/aac.03588-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 11/05/2014] [Indexed: 12/17/2022] Open
Abstract
The translational value of zebrafish high-throughput screens can be improved when more knowledge is available on uptake characteristics of potential drugs. We investigated reference antibiotics and 15 preclinical compounds in a translational zebrafish-rodent screening system for tuberculosis. As a major advance, we have developed a new tool for testing drug uptake in the zebrafish model. This is important, because despite the many applications of assessing drug efficacy in zebrafish research, the current methods for measuring uptake using mass spectrometry do not take into account the possible adherence of drugs to the larval surface. Our approach combines nanoliter sampling from the yolk using a microneedle, followed by mass spectrometric analysis. To date, no single physicochemical property has been identified to accurately predict compound uptake; our method offers a great possibility to monitor how any novel compound behaves within the system. We have correlated the uptake data with high-throughput drug-screening data from Mycobacterium marinum-infected zebrafish larvae. As a result, we present an improved zebrafish larva drug-screening platform which offers new insights into drug efficacy and identifies potential false negatives and drugs that are effective in zebrafish and rodents. We demonstrate that this improved zebrafish drug-screening platform can complement conventional models of in vivo Mycobacterium tuberculosis-infected rodent assays. The detailed comparison of two vertebrate systems, fish and rodent, may give more predictive value for efficacy of drugs in humans.
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Affiliation(s)
- Anita Ordas
- IBL, Leiden University, Leiden, The Netherlands
| | - Robert-Jan Raterink
- Division of Analytical BioSciences, Leiden Academic Centre for Drug Research and Netherlands Metabolomics Centre, Leiden University, Leiden, The Netherlands
| | | | | | - Malgorzata I Wiweger
- IBL, Leiden University, Leiden, The Netherlands ZF-screens B.V., Leiden, The Netherlands
| | | | - Sabine Bos
- Division of Analytical BioSciences, Leiden Academic Centre for Drug Research and Netherlands Metabolomics Centre, Leiden University, Leiden, The Netherlands
| | | | | | | | - Rob J Vreeken
- Division of Analytical BioSciences, Leiden Academic Centre for Drug Research and Netherlands Metabolomics Centre, Leiden University, Leiden, The Netherlands
| | | | | | - Thomas Hankemeier
- Division of Analytical BioSciences, Leiden Academic Centre for Drug Research and Netherlands Metabolomics Centre, Leiden University, Leiden, The Netherlands
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280
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Compton CL, Carney DW, Groomes PV, Sello JK. Fragment-Based Strategy for Investigating and Suppressing the Efflux of Bioactive Small Molecules. ACS Infect Dis 2015; 1:53-8. [PMID: 27620145 DOI: 10.1021/id500009f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Membrane protein-mediated drug efflux is a phenomenon that compromises our ability to treat both infectious diseases and cancer. Accordingly, there is much interest in the development of strategies for suppression of the mechanisms by which therapeutic agents are effluxed. Here, using resistance to the cyclic acyldepsipeptide (ADEP) antibacterial agents as a model, we demonstrate a new counter-efflux strategy wherein a fragment of an actively exported bioactive compound competitively interferes with its efflux and potentiates its activity. A fragment comprising the N-heptenoyldifluorophenylalanine side chain of the pharmacologically optimized ADEPs potentiates the antibacterial activity of the ADEPs against actinobacteria to a greater extent than reserpine, a well-known efflux inhibitor. Beyond their validation of a new approach to studying molecular recognition by drug efflux pumps, our findings have important implications for killing Mycobacterium tuberculosis with ADEPs and reclaiming the efficacies of therapeutic agents whose activity has been compromised by efflux pumps.
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Affiliation(s)
- Corey L. Compton
- Department of Chemistry, Brown University, 324 Brook
Street, Providence, Rhode
Island 02912, United States
| | - Daniel W. Carney
- Department of Chemistry, Brown University, 324 Brook
Street, Providence, Rhode
Island 02912, United States
| | - Patrice V. Groomes
- Department of Chemistry, Brown University, 324 Brook
Street, Providence, Rhode
Island 02912, United States
| | - Jason K. Sello
- Department of Chemistry, Brown University, 324 Brook
Street, Providence, Rhode
Island 02912, United States
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281
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Manina G, Dhar N, McKinney J. Stress and Host Immunity Amplify Mycobacterium tuberculosis Phenotypic Heterogeneity and Induce Nongrowing Metabolically Active Forms. Cell Host Microbe 2015; 17:32-46. [DOI: 10.1016/j.chom.2014.11.016] [Citation(s) in RCA: 212] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/19/2014] [Accepted: 11/06/2014] [Indexed: 11/28/2022]
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282
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Abstract
The intrinsic resistance of mycobacteria to most antimicrobial agents is mainly attributed to the synergy between their relatively impermeable cell wall and efflux systems. The mycobacterial cell wall is rich in lipids and polysaccharides making a compact envelope that limits drug uptake. Changes in cell wall composition or structure lead to variations in susceptibility to drugs. Bacterial efflux pumps are membrane proteins that are capable of actively transporting a broad range of substrates, including drugs, from the cytoplasm to the extracellular environment. Increased expression of efflux pump genes confers a low level resistance phenotype, and under these conditions, bacteria may have greater chances of acquiring chromosomal mutation(s) conferring higher levels of drug resistance. In order to develop effective antimycobacterial therapeutic strategies, the contributions to drug resistance made by the limited permeability of the cell wall and the increased expression of efflux pumps must be understood. In this chapter, we describe a method that allows: (1) the quantification of general efflux activity of mycobacterial strains (clinical isolates, mutants impaired in efflux or permeability) by the study of the transport (influx and efflux) of fluorescent compounds, such as ethidium bromide; and (2) the screening of compounds in search of inhibitors of efflux pumps, which could restore the effectiveness of antimicrobials that are subject to efflux.
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Affiliation(s)
- Liliana Rodrigues
- Grupo de Genética de Micobacterias, Departamento de Microbiología, Medicina Preventiva y Salud Publica, Facultad de Medicina, Universidad de Zaragoza, C/ Domingo Miral s/n, Zaragoza, 50009, Spain
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283
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Oosterhof N, Boddeke E, van Ham TJ. Immune cell dynamics in the CNS: Learning from the zebrafish. Glia 2014; 63:719-35. [PMID: 25557007 DOI: 10.1002/glia.22780] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/10/2014] [Indexed: 12/22/2022]
Abstract
A major question in research on immune responses in the brain is how the timing and nature of these responses influence physiology, pathogenesis or recovery from pathogenic processes. Proper understanding of the immune regulation of the human brain requires a detailed description of the function and activities of the immune cells in the brain. Zebrafish larvae allow long-term, noninvasive imaging inside the brain at high-spatiotemporal resolution using fluorescent transgenic reporters labeling specific cell populations. Together with recent additional technical advances this allows an unprecedented versatility and scope of future studies. Modeling of human physiology and pathology in zebrafish has already yielded relevant insights into cellular dynamics and function that can be translated to the human clinical situation. For instance, in vivo studies in the zebrafish have provided new insight into immune cell dynamics in granuloma formation in tuberculosis and the mechanisms involving treatment resistance. In this review, we highlight recent findings and novel tools paving the way for basic neuroimmunology research in the zebrafish. GLIA 2015;63:719-735.
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Affiliation(s)
- Nynke Oosterhof
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
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284
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The efflux pump inhibitor timcodar improves the potency of antimycobacterial agents. Antimicrob Agents Chemother 2014; 59:1534-41. [PMID: 25534740 DOI: 10.1128/aac.04271-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies indicated that inhibition of efflux pumps augments tuberculosis therapy. In this study, we used timcodar (formerly VX-853) to determine if this efflux pump inhibitor could increase the potency of antituberculosis (anti-TB) drugs against Mycobacterium tuberculosis in in vitro and in vivo combination studies. When used alone, timcodar weakly inhibited M. tuberculosis growth in broth culture (MIC, 19 μg/ml); however, it demonstrated synergism in drug combination studies with rifampin, bedaquiline, and clofazimine but not with other anti-TB agents. When M. tuberculosis was cultured in host macrophage cells, timcodar had about a 10-fold increase (50% inhibitory concentration, 1.9 μg/ml) in the growth inhibition of M. tuberculosis and demonstrated synergy with rifampin, moxifloxacin, and bedaquiline. In a mouse model of tuberculosis lung infection, timcodar potentiated the efficacies of rifampin and isoniazid, conferring 1.0 and 0.4 log10 reductions in bacterial burden in lung, respectively, compared to the efficacy of each drug alone. Furthermore, timcodar reduced the likelihood of a relapse infection when evaluated in a mouse model of long-term, chronic infection with treatment with a combination of rifampin, isoniazid, and timcodar. Although timcodar had no effect on the pharmacokinetics of rifampin in plasma and lung, it did increase the plasma exposure of bedaquiline. These data suggest that the antimycobacterial drug-potentiating activity of timcodar is complex and drug dependent and involves both bacterial and host-targeted mechanisms. Further study of the improvement of the potency of antimycobacterial drugs and drug candidates when used in combination with timcodar is warranted.
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285
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Host Evasion and Exploitation Schemes of Mycobacterium tuberculosis. Cell 2014; 159:1497-509. [DOI: 10.1016/j.cell.2014.11.024] [Citation(s) in RCA: 269] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Indexed: 12/20/2022]
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286
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Ordonez AA, Maiga M, Gupta S, Weinstein EA, Bishai WR, Jain SK. Novel adjunctive therapies for the treatment of tuberculosis. Curr Mol Med 2014; 14:385-95. [PMID: 24236454 DOI: 10.2174/1566524013666131118112431] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 07/07/2013] [Accepted: 08/05/2013] [Indexed: 11/22/2022]
Abstract
Despite significant efforts to control tuberculosis (TB), the disease remains a major global threat, with an estimated 8.6 million new cases and 1.3 million deaths in 2012 alone. Significant treatment challenges include HIV co-infection, the dramatic rise of multidrug-resistant TB and the vast reservoir of latently infected individuals, who will develop active disease years after the initial infection. The long duration of chemotherapy also remains a major barrier to effective large scale treatment of TB. Significant advances are being made in the development of shorter and effective TB drug regimens and there is growing evidence that host-directed and "non-antimicrobial" pathogen-directed therapies, could serve as novel approaches to enhance TB treatments. This review highlights the rationale for using these therapies and summarizes some of the progress in this field.
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Affiliation(s)
| | | | | | | | | | - S K Jain
- Center for Infection and Inflammation Imaging Research, 1550 Orleans Street, Rm 1.09, Baltimore, MD 21287, USA.
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287
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van Leeuwen LM, van der Sar AM, Bitter W. Animal models of tuberculosis: zebrafish. Cold Spring Harb Perspect Med 2014; 5:a018580. [PMID: 25414379 DOI: 10.1101/cshperspect.a018580] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Over the past decade the zebrafish (Danio rerio) has become an attractive new vertebrate model organism for studying mycobacterial pathogenesis. The combination of medium-throughput screening and real-time in vivo visualization has allowed new ways to dissect host pathogenic interaction in a vertebrate host. Furthermore, genetic screens on the host and bacterial sides have elucidated new mechanisms involved in the initiation of granuloma formation and the importance of a balanced immune response for control of mycobacterial pathogens. This article will highlight the unique features of the zebrafish-Mycobacterium marinum infection model and its added value for tuberculosis research.
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Affiliation(s)
- Lisanne M van Leeuwen
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands Department of Medical Microbiology and Infection control, VU University Medical Center, 1081 BT Amsterdam, The Netherlands
| | - Astrid M van der Sar
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - Wilbert Bitter
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands Department of Molecular Microbiology, VU University, 1081 HV Amsterdam, The Netherlands
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288
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Raffetseder J, Pienaar E, Blomgran R, Eklund D, Patcha Brodin V, Andersson H, Welin A, Lerm M. Replication rates of Mycobacterium tuberculosis in human macrophages do not correlate with mycobacterial antibiotic susceptibility. PLoS One 2014; 9:e112426. [PMID: 25386849 PMCID: PMC4227709 DOI: 10.1371/journal.pone.0112426] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/15/2014] [Indexed: 11/19/2022] Open
Abstract
The standard treatment of tuberculosis (TB) takes six to nine months to complete and this lengthy therapy contributes to the emergence of drug-resistant TB. TB is caused by Mycobacterium tuberculosis (Mtb) and the ability of this bacterium to switch to a dormant phenotype has been suggested to be responsible for the slow clearance during treatment. A recent study showed that the replication rate of a non-virulent mycobacterium, Mycobacterium smegmatis, did not correlate with antibiotic susceptibility. However, the question whether this observation also holds true for Mtb remains unanswered. Here, in order to mimic physiological conditions of TB infection, we established a protocol based on long-term infection of primary human macrophages, featuring Mtb replicating at different rates inside the cells. During conditions that restricted Mtb replication, the bacterial phenotype was associated with reduced acid-fastness. However, these phenotypically altered bacteria were as sensitive to isoniazid, pyrazinamide and ethambutol as intracellularly replicating Mtb. In support of the recent findings with M. smegmatis, we conclude that replication rates of Mtb do not correlate with antibiotic tolerance.
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Affiliation(s)
- Johanna Raffetseder
- Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, SE-58185, Sweden
| | - Elsje Pienaar
- Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, SE-58185, Sweden
| | - Robert Blomgran
- Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, SE-58185, Sweden
| | - Daniel Eklund
- Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, SE-58185, Sweden
| | - Veronika Patcha Brodin
- Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, SE-58185, Sweden
| | - Henrik Andersson
- Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, SE-58185, Sweden
| | - Amanda Welin
- Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, SE-58185, Sweden
| | - Maria Lerm
- Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, SE-58185, Sweden
- * E-mail:
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289
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Pagán AJ, Ramakrishnan L. Immunity and Immunopathology in the Tuberculous Granuloma. Cold Spring Harb Perspect Med 2014; 5:cshperspect.a018499. [PMID: 25377142 DOI: 10.1101/cshperspect.a018499] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Granulomas, organized aggregates of immune cells, are a defining feature of tuberculosis (TB). Granuloma formation is implicated in the pathogenesis of a variety of inflammatory disorders. However, the tuberculous granuloma has been assigned the role of a host protective structure which "walls-off" mycobacteria. Work conducted over the past decade has provided a more nuanced view of its role in pathogenesis. On the one hand, pathogenic mycobacteria accelerate and exploit granuloma formation for their expansion and dissemination by manipulating host immune responses to turn leukocyte recruitment and cell death pathways in their favor. On the other hand, granuloma macrophages can preserve granuloma integrity by exerting a microbicidal immune response, thus preventing an even more rampant expansion of infection in the extracellular milieu. Even this host-beneficial immune response required to maintain the bacteria intracellular must be tempered, as an overly vigorous immune response can also cause granuloma breakdown, thereby directly supporting bacterial growth extracellularly. This review will discuss how mycobacteria manipulate inflammatory responses to drive granuloma formation and will consider the roles of the granuloma in pathogenesis and protective immunity, drawing from clinical studies of TB in humans and from animal models--rodents, zebrafish, and nonhuman primates. A deeper understanding of TB pathogenesis and immunity in the granuloma could suggest therapeutic approaches to abrogate the host-detrimental aspects of granuloma formation to convert it into the host-beneficial structure that it has been thought to be for nearly a century.
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Affiliation(s)
- Antonio J Pagán
- Department of Microbiology, University of Washington, Seattle, Washington 98195
| | - Lalita Ramakrishnan
- Department of Microbiology, University of Washington, Seattle, Washington 98195 Department of Medicine, University of Washington, Seattle, Washington 98195 Department of Immunology, University of Washington, Seattle, Washington 98195
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290
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291
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Verapamil increases the bactericidal activity of bedaquiline against Mycobacterium tuberculosis in a mouse model. Antimicrob Agents Chemother 2014; 59:673-6. [PMID: 25331694 DOI: 10.1128/aac.04019-14] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bedaquiline is a newly approved drug for the treatment of multidrug-resistant tuberculosis, but there are concerns about its safety in humans. We found that the coadministration of verapamil with subinhibitory doses of bedaquiline gave the same bactericidal effect in mice as did the full human bioequivalent bedaquiline dosing. Adding verapamil to bedaquiline monotherapy also protected against the development of resistant mutants in vivo. The adjunctive use of verapamil may permit use of lower doses of bedaquiline to be used and thereby reduce its dose-related toxicities in tuberculosis patients.
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292
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Mycobacterium tuberculosis strains lacking surface lipid phthiocerol dimycocerosate are susceptible to killing by an early innate host response. Infect Immun 2014; 82:5214-22. [PMID: 25287926 DOI: 10.1128/iai.01340-13] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The innate immune response plays an important but unknown role in host defense against Mycobacterium tuberculosis. To define the function of innate immunity during tuberculosis, we evaluated M. tuberculosis replication dynamics during murine infection. Our data show that the early pulmonary innate immune response limits M. tuberculosis replication in a MyD88-dependent manner. Strikingly, we found that little M. tuberculosis cell death occurs during the first 2 weeks of infection. In contrast, M. tuberculosis cells deficient in the surface lipid phthiocerol dimycocerosate (PDIM) exhibited significant death rates, and consequently, total bacterial numbers were reduced. Host restriction of PDIM-deficient M. tuberculosis was not alleviated by the absence of interferon gamma (IFN-γ), inducible nitric oxide synthase (iNOS), or the phagocyte oxidase subunit p47. Taken together, these data indicate that PDIM protects M. tuberculosis from an early innate host response that is independent of IFN-γ, reactive nitrogen intermediates, and reactive oxygen species. By employing a pathogen replication tracking tool to evaluate M. tuberculosis replication and death during infection, we identify both host and pathogen factors affecting the outcome of infection.
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293
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Dutta NK, Karakousis PC. Thioridazine for treatment of tuberculosis: promises and pitfalls. Tuberculosis (Edinb) 2014; 94:708-11. [PMID: 25293998 DOI: 10.1016/j.tube.2014.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/04/2014] [Indexed: 12/23/2022]
Abstract
The articles by De Knegt et al. and Singh et al. in a recent issue of this Journal address one of the current debates regarding the potential role of thioridazine in the treatment of tuberculosis. This commentary presents a summary of the available evidence, and, emphasizing the need for further research, asks the question: "How far can we go in repurposing thioridazine?"
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Affiliation(s)
- Noton K Dutta
- Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Petros C Karakousis
- Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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294
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LprG-mediated surface expression of lipoarabinomannan is essential for virulence of Mycobacterium tuberculosis. PLoS Pathog 2014; 10:e1004376. [PMID: 25232742 PMCID: PMC4169494 DOI: 10.1371/journal.ppat.1004376] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 07/28/2014] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium tuberculosis employs various virulence strategies to subvert host immune responses in order to persist and cause disease. Interaction of M. tuberculosis with mannose receptor on macrophages via surface-exposed lipoarabinomannan (LAM) is believed to be critical for cell entry, inhibition of phagosome-lysosome fusion, and intracellular survival, but in vivo evidence is lacking. LprG, a cell envelope lipoprotein that is essential for virulence of M. tuberculosis, has been shown to bind to the acyl groups of lipoglycans but the role of LprG in LAM biosynthesis and localization remains unknown. Using an M. tuberculosis lprG mutant, we show that LprG is essential for normal surface expression of LAM and virulence of M. tuberculosis attributed to LAM. The lprG mutant had a normal quantity of LAM in the cell envelope, but its surface was altered and showed reduced expression of surface-exposed LAM. Functionally, the lprG mutant was defective for macrophage entry and inhibition of phagosome-lysosome fusion, was attenuated in macrophages, and was killed in the mouse lung with the onset of adaptive immunity. This study identifies the role of LprG in surface-exposed LAM expression and provides in vivo evidence for the essential role surface LAM plays in M. tuberculosis virulence. Findings have translational implications for therapy and vaccine development. Mycobacterium tuberculosis is among the leading infectious causes of human death. A better understanding of its virulence mechanisms is needed to facilitate development of novel therapeutics and a preventative vaccine. Lipoarabinomannan (LAM), an abundant surface-exposed lipoglycan, is believed to be a critical virulence determinant for intracellular survival and latency of M. tuberculosis. In vitro experiments with purified LAM have led to a model in which surface-exposed LAM binds to macrophage mannose receptor and facilitates bacterium entry, inhibition of phagosome-lysosome fusion, and modulation of innate immune responses. However, confirmation of these findings in vivo has not been possible due to the essentiality of genes involved in the LAM biosynthetic pathway. It was recently shown that LprG, a cell envelope lipoprotein, binds to the acyl groups of lipoglycan, but the role of LprG in LAM biosynthesis and localization remains unknown. Here, using an M. tuberculosis lprG mutant and a novel cell-imprinting assay, we show that LprG is essential for normal surface expression of LAM and virulence of M. tuberculosis attributed to LAM. Our study provides new insights into the mechanism of surface expression of LAM and confirms the essential role surface LAM serves in pathogenesis of M. tuberculosis.
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295
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Worley MV, Estrada SJ. Bedaquiline: a novel antitubercular agent for the treatment of multidrug-resistant tuberculosis. Pharmacotherapy 2014; 34:1187-97. [PMID: 25203970 DOI: 10.1002/phar.1482] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Bedaquiline is a diarylquinoline antitubercular drug with a novel mechanism of action against Mycobacterium tuberculosis. Bedaquiline works by inhibiting bacterial adenosine triphosphate (ATP) synthase and represents the first novel class of antituberculosis agents in more than 40 years. Bedaquiline is indicated for the treatment of multidrug-resistant tuberculosis (MDR TB) in combination with at least three other antitubercular drugs when no other effective regimen is available. The recommended bedaquiline dosage is 400 mg orally once/day for 2 weeks followed by 200 mg orally 3 times/week for 22 weeks. Bedaquiline should be administered with food, which increases the bioavailability 2-fold. Bedaquiline is metabolized by cytochrome P450 isoenzyme 3A4 and is impacted by both inducers and inhibitors of this isoenzyme. Concentration-dependent bactericidal activity was observed in laboratory and murine studies. Accelerated approval was granted in the United States and European Union based on the results of two phase IIb clinical studies that used sputum culture clearance as a surrogate end point for clinical efficacy. These studies showed greater sputum culture clearance up to week 24 for the bedaquiline group compared with placebo. Common adverse events in clinical trials included nausea, arthralgia, and headache. Serious adverse events included elevated serum transaminase levels and rate-corrected QT-interval prolongation. Unexplained higher mortality was seen in patients receiving bedaquiline versus those receiving placebo. Bedaquiline is a novel agent with a unique mechanism of action and has the potential to meet a great need in patients with MDR TB who have no other treatment options. Due to safety concerns and limited clinical information, phase III trials are needed to fully determine its place in therapy.
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Affiliation(s)
- Marylee V Worley
- Department of Pharmacy, Lee Memorial Health System, Fort Myers, Florida
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296
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Claudi B, Spröte P, Chirkova A, Personnic N, Zankl J, Schürmann N, Schmidt A, Bumann D. Phenotypic Variation of Salmonella in Host Tissues Delays Eradication by Antimicrobial Chemotherapy. Cell 2014; 158:722-733. [DOI: 10.1016/j.cell.2014.06.045] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 05/15/2014] [Accepted: 06/06/2014] [Indexed: 11/24/2022]
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297
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Fenaroli F, Westmoreland D, Benjaminsen J, Kolstad T, Skjeldal FM, Meijer AH, van der Vaart M, Ulanova L, Roos N, Nyström B, Hildahl J, Griffiths G. Nanoparticles as drug delivery system against tuberculosis in zebrafish embryos: direct visualization and treatment. ACS NANO 2014; 8:7014-7026. [PMID: 24945994 DOI: 10.1021/nn5019126] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Nanoparticles (NPs) enclosing antibiotics have provided promising therapy against Mycobacterium tuberculosis (Mtb) in different mammalian models. However, the NPs were not visualized in any of these animal studies. Here, we introduce the transparent zebrafish embryo as a system for noninvasive, simultaneous imaging of fluorescent NPs and the fish tuberculosis (TB) agent Mycobacterium marinum (Mm). The study was facilitated by the use of transgenic lines of macrophages, neutrophils, and endothelial cells expressing fluorescent markers readily visible in the live vertebrate. Intravenous injection of Mm led to phagocytosis by blood macrophages. These remained within the vasculature until 3 days postinfection where they started to extravasate and form aggregates of infected cells. Correlative light/electron microscopy revealed that these granuloma-like structures had significant access to the vasculature. Injection of NPs induced rapid uptake by both infected and uninfected macrophages, the latter being actively recruited to the site of infection, thereby providing an efficient targeting into granulomas. Rifampicin-loaded NPs significantly improved embryo survival and lowered bacterial load, as shown by quantitative fluorescence analysis. Our results argue that zebrafish embryos offer a powerful system for monitoring NPs in vivo and rationalize why NP therapy was so effective against Mtb in earlier studies; bacteria and NPs share the same cellular niche.
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Affiliation(s)
- Federico Fenaroli
- Department of Biosciences, University of Oslo , Blindernveien 31, 0371 Oslo, Norway
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298
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Reves R, Schluger NW. Update in tuberculosis and nontuberculous mycobacterial infections 2013. Am J Respir Crit Care Med 2014; 189:894-8. [PMID: 24735031 DOI: 10.1164/rccm.201402-0210up] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Randall Reves
- 1 Department of Medicine, University of Colorado, Denver, Colorado
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299
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Characterization of a Mycobacterium avium subsp. avium operon associated with virulence and drug detoxification. BIOMED RESEARCH INTERNATIONAL 2014; 2014:809585. [PMID: 24967408 PMCID: PMC4055363 DOI: 10.1155/2014/809585] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/02/2014] [Indexed: 11/24/2022]
Abstract
The lprG-p55 operon of Mycobacterium tuberculosis and Mycobacterium bovis is involved in the transport of toxic compounds. P55 is an efflux pump that provides resistance to several drugs, while LprG is a lipoprotein that modulates the host's immune response against mycobacteria. The knockout mutation of this operon severely reduces the replication of both mycobacterial species during infection in mice and increases susceptibility to toxic compounds. In order to gain insight into the function of LprG in the Mycobacterium avium complex, in this study, we assayed the effect of the deletion of lprG gene in the D4ER strain of Mycobacterium avium subsp. avium. The replacement of lprG gene with a hygromycin cassette caused a polar effect on the expression of p55. Also, a twofold decrease in ethidium bromide susceptibility was observed and the resistance to the antibiotics rifampicin, amikacin, linezolid, and rifabutin was impaired in the mutant strain. In addition, the mutation decreased the virulence of the bacteria in macrophages in vitro and in a mice model in vivo. These findings clearly indicate that functional LprG and P55 are necessary for the correct transport of toxic compounds and for the survival of MAA in vitro and in vivo.
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300
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Singh K, Kumar M, Pavadai E, Naran K, Warner DF, Ruminski PG, Chibale K. Synthesis of new verapamil analogues and their evaluation in combination with rifampicin against Mycobacterium tuberculosis and molecular docking studies in the binding site of efflux protein Rv1258c. Bioorg Med Chem Lett 2014; 24:2985-90. [PMID: 24894561 DOI: 10.1016/j.bmcl.2014.05.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/08/2014] [Accepted: 05/09/2014] [Indexed: 11/19/2022]
Abstract
New verapamil analogues were synthesized and their inhibitory activities against Mycobacterium tuberculosis H37Rv determined in vitro alone and in combination with rifampicin (RIF). Some analogues showed comparable activity to verapamil and exhibited better synergies with RIF. Molecular docking studies of the binding sites of Rv1258c, a M. tuberculosis efflux protein previously implicated in intrinsic resistance to RIF, suggested a potential rationale for the superior synergistic interactions observed with some analogues.
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Affiliation(s)
- Kawaljit Singh
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Malkeet Kumar
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Elumalai Pavadai
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Krupa Naran
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Division of Medical Microbiology, University of Cape Town, Rondebosch 7701, South Africa
| | - Digby F Warner
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Division of Medical Microbiology, University of Cape Town, Rondebosch 7701, South Africa; Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | - Peter G Ruminski
- Centre for World Health and Medicine, Saint Louis University, USA
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa; South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa; Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa.
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