DOCSLIB.ORG

Drug Targets in Leishmania

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Drug Targets in Leishmania View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Publications of the IAS Fellows J Parasit Dis DOI 10.1007/s12639-010-0006-3 REVIEW ARTICLE Drug targets in Leishmania Bhavna Chawla • Rentala Madhubala Received: 30 April 2010 / Accepted: 22 June 2010 Ó Indian Society for Parasitology 2010 Abstract Leishmaniasis is a major public health problem Leishmania. It constitutes of a wide spectrum of diseases and till date there are no effective vaccines available. The ranging in severity from simple cutaneous lesions to the control strategy relies solely on chemotherapy of the infec- usually fatal visceral form. The parasite is transmitted ted people. However, the present repertoire of drugs is through the bite of sandfly to the mammalian hosts. The limited and increasing resistance towards them has posed a disease is endemic in 88 countries and affects as many as major concern. The first step in drug discovery is to identify 12 million people around the globe with an incidence of a suitable drug target. The genome sequences of Leishmania 0.5 million cases of the visceral form of the disease and major and Leishmania infantum has revealed immense 1.5–2.0 million cases of the cutaneous form of the disease, amount of information and has given the opportunity to causing extensive mortality and morbidity. identify novel drug targets that are unique to these parasites. Since, effective vaccines against leishmaniasis are still Utilization of this information in order to come up with a under development, the current control measures rely candidate drug molecule requires combining all the tech- solely on chemotherapy. Pentavalent antimonials are the nology and using a multi-disciplinary approach, right from standard first line of treatment but emergence of resistance characterizing the target protein to high throughput screen- towards them, has limited their usefulness. Alternative ing of compounds. Leishmania belonging to the order ki- chemotherapeutic treatments with amphotericin B and its netoplastidae emerges from the ancient eukaryotic lineages. lipid formulation, miltefosine and paromomycin are They are quite diverse from their mammalian hosts and there available but their use is limited either due to toxicity or are several cellular processes that we are getting to know of, high cost of treatment. The current challenges in the che- which exist distinctly in these parasites. In this review, we motherapy include availability of very few drugs, emer- discuss some of the metabolic pathways that are essential gence of resistance to the existing drugs, their toxicity and and could be used as potential drug targets in Leishmania. lack of cost-effectiveness. Therefore, it is of utmost importance to look for effective drugs and new drug targets Keywords Leishmaniasis Á Leishmania Á for the treatment of leishmaniasis. Metabolic pathways Á Drug targets There seems to be a welcome change in terms of flow of funds for antiparasitic drug discovery. Some of the or- ganisations like Institute of One World Health (IOWH), Introduction Drugs for Neglected Diseases Initiative (DNDi), Bill and Melinda Gates foundation have had a significant impact on Leishmaniasis is a group of parasitic diseases caused by at working towards the drug development for tropical dis- least 20 different species of the protozoan parasite eases. This has enabled technological advances in the field, which includes publicly funded sequencing of the gen- omes, thus fastening up the course towards drug develop- & B. Chawla Á R. Madhubala ( ) ment. A major breakthrough in the field is the availability School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India of the complete genome sequence of various species of e-mail: [email protected] Leishmania like, L. major (Ivens et al. 2005), L. infantum 123 J Parasit Dis and L. braziliensis. It has provided us with enormous structure. Unlike mammalian cells, which have cholesterol information about the parasite genome for our better as the major membrane sterol, trypanosomatids synthesize understanding of these organisms. With the availability and ergosterol and other 24-methyl sterols that are required for easily accessible genome sequences, the conventional their growth and viability. These sterols are absent from the method of drug target identification, which was done on the mammalian cells. Therefore, the sterol biosynthetic path- basis of the biochemical and physiological differences way from Leishmania is considered to be an important drug between the pathogen and host, is now changing. Micro- target (Fig. 1). arrays and proteome analysis make use of the genome One of the enzymes that is being studied deeply is sequences and has allowed us to find genes unique to the squalene synthase (SQS) (EC 2.5.1.21) that catalyzes the parasite, some species-specific genes that can help us first committed step of sterol synthesis by coupling two understand the pathogen better. Several bioinformatic farnesyl molecules to form squalene. Zaragozic acids and approaches have also been proposed which will fasten the quinuclidines are known to inhibit SQS. Two quinuclidine pace to come up with anti-leishmanial drugs (Myler 2008). derivatives, ER-119884 and E5700 have been shown to be The analysis of the complete genome sequence may sig- potent anti-Leishmania (Fernandes Rodrigues et al. 2008) nificantly contribute in drug development by revealing the and Trypanosoma (Urbina et al. 2004) agents. The inhibi- presence of novel enzymes and receptors. Furthermore, the tion of SQS by these compounds decreased the parasite’s comparison of the parasite genome with the human genome endogenous sterol levels which had an antiproliferative sequence will make the identification of genes, unique to effect on the parasite. In L. amazonensis,IC50 value of the parasite, easier. ER-119884 and E5700 for promastigotes was found to be 10 and 30 nM respectively (Fernandes Rodrigues et al. 2008). Squalene is converted to 2,3-oxidosqualene by the Identification of drug targets enzyme squalene epoxidase (EC 1.14.99.7). It converts One of the characteristic features in the process of drug development is target identification in a biological path- Acetyl-CoA way. In theory, during identification of a target in a path- HMG-CoA reductase ogen, it is important that the putative target should be either absent in the host or substantially different from the host 3-hydroxy-3-methyl-glutaryl-CoA homolog so that it can be exploited as a drug target. Try- panosomatids, phylogenetically, branch out quite early Mevalonate from the higher eukaryotes. In fact, their cell organization Isopentyl-PP Dimethylallyl-PP is significantly different from the mammalian cells and thus, it is possible to find targets that are unique to these Farnesyl-PP Synthase Isoprenoid Pathway pathogens. Secondly, the target selected should be abso- lutely necessary for the survival of the pathogen. It is also Geranyl-PP important to consider the stage of the life-cycle of the Farnesyl-PP Synthase pathogen in which the target gene is expressed. It is crucial Farnesyl-PP to look at the biochemical properties of the protein; it Squalene Synthase should have a small molecule binding pocket, so that Squalene specific inhibitors can be designed and if the target protein Squalene epoxidase is an enzyme, its inhibition should lead to loss in cell 2,3-oxidosqualene viability. It is of high importance that the target selected should be assayable. Inexpensive and specific assay system Lanosterol should be available for high-throughput screening of mol- ecules (Pink et al. 2005; Barrett et al. 1999). Zimosterol Sterol Methyltransferase Potential drug targets in Leishmania Ergosterol Sterol biosynthetic pathway Fig. 1 Sterol biosynthetic pathway in Leishmania. The pathway shows the important steps and the enzymes involved in sterol Sterols are important components of the cell membrane biosynthesis. The final product in trypanosomatids is ergosterol as that are vital to cellular function and maintenance of cell opposed to cholesterol in mammalian cells 123 J Parasit Dis squalene chain to tetracyclic sterol skeleton. Terbinafine, being employed to obtain compounds that bind to the an allylamine, is known to inhibit squalene epoxidase. It enzymes with high affinity. The 3-D structures are available has been shown that terbinafine inhibits the growth of for some of the trypanosomatid enzymes: glyceraldehydes- promastigotes and intracellular amastigotes and leads to 3-phosphate dehydrogenase (EC 1.2.7.6) (Vellieux et al. changes in structural organization in mitochondrion (Van- 1993; Kim et al. 1995), triosephosphate isomerase (5.3.1.1) nier-Santos et al. 1995). When it is used in combination (Wierenga et al. 1991; Williams et al. 1999), phosphoglyc- with ketoconazole, another inhibitor of ergosterol biosyn- erate kinase (EC 2.7.2.10) (Bernstein et al. 1997), pyruvate thesis, the effect is synergistic. Another class of inhibitors, kinase (2.7.1.40) (Rigden et al. 1999), fructose-1,6-bis- bisphosphonates, inhibits the isoprenoid pathway that is phosphate aldolase (EC 4.1.2.13) (Chudzik et al. 2000) and catalyzed by the enzyme farnesyl diphosphate synthase glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) (Suresh (FPPS). They have been tested in vivo and in vitro against et al. 2000). The differences in the 3-D structures of the the protozoan parasites (Martin et al. 2001; Docampo parasite and host enzymes can be used to design specific and Moreno 2008). A potent inhibition of the cell growth inhibitors (Verlinde and Hol 1994). and suppression of the activity of isolated enzymes (from Specific inhibitors have been designed for the glycolytic L. major) was observed thus validating the isoprenoid enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) pathway as a drug target. based on its crystal structure. Adenosine analogs were syn- Another important putative target in ergosterol biosyn- thesized as tight binding inhibitors that occupy the pocket on thesis is the enzyme D24,25-sterol methyltransferase (SMT) the enzyme that accommodates adenosyl moiety of NAD? (EC 2.1.1.41).
Load more

Recommended publications
  • Kohen Curriculum Vitae
    Curriculum Vitae Amnon Kohen Department of Chemistry Tel: (319) 335-0234 University of Iowa FAX: (319) 335-1270 Iowa City, IA 52242 [email protected] EDUCATION AND PROFESSIONAL HISTORY Education D.Sc., Chemistry 1989-1994 Technion – Israel Institute of Technology, Haifa, Israel Advisor: Professor T. Baasov Topic: Mechanistic Studies of the Enzyme KDO8P Synthase B.Sc., Chemistry (with Honors) 1986-1989 Hebrew University, Jerusalem, Israel Positions Professor 2010-Present Department of Chemistry, University of Iowa, Iowa City, IA and Molecular and Cellular Biology Program, and MSTP faculty member Associate Professor 2005-2010 Department of Chemistry, University of Iowa, Iowa City, IA and Molecular and Cellular Biology Program Assistant Professor 1999-2005 Department of Chemistry, University of Iowa, Iowa City, IA Postgraduate Researcher 1997-1999 With Professor Judith Klinman Department of Chemistry, University of California, Berkeley Topic: Hydrogen Tunneling in Biology: Alcohol Dehydrogenases Postgraduate Fellow 1995-1997 With Professor Judith Klinman Department of Chemistry, University of California, Berkeley Topic: Hydrogen Tunneling in Biology: Glucose Oxidase Visiting Scholar Fall 1994 With Professor Karen S. Anderson Department of Pharmacology, Yale Medical School, New Haven, CT Kohen, A. Affiliations American Society for Biochemistry and Molecular Biology (ASBMB, 2013 - present) Center for Biocatalysis and Bioprocessing (CBB) University of Iowa (2000-Present) The Interdisciplinary Graduate Program in Molecular Biology, University of Iowa (2003- Present) American Association for the Advancement of Science (AAAS, 2011-present) American Chemical Society (1995-Present) Divisions: Organic Chemistry, Physical Chemistry, Biochemistry Sigma Xi (1997-Present) Protein Society (1996-1998) Honors and Awards • Career Development Award (University of Iowa- 2015-2016) • Graduate College Outstanding Faculty Mentor Award (2015).
    [Show full text]
  • Molecular Cloning, Expression and Enzymatic Assay of Pteridine Reductase 1 from Iranian Lizard Leishmania
    Iranian Biomedical Journal 14 (3): 97-102 (July 2010) Molecular Cloning, Expression and Enzymatic Assay of Pteridine Reductase 1 from Iranian Lizard Leishmania Bahram Kazemi*1,2, Farideh Tohidi3,4, Mojgan Bandehpour1 and Fatemeh Yarian1 1Cellular and Molecular Biology Research Center and 2Dept. of Parasitology and Mycology, Shahid Beheshti University, Tehran; 3Dept. of Parasitology and Mycology, Gorgan University of Medical Sciences, Gorgan; 4Bu-Ali Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran Received 17 April 2010; revised 17 July 2010; accepted 24 July 2010 ABSTRACT Background: Currently, there are no effective vaccines against leishmaniasis, and treatment using pentavalent antimonial drugs is occasionally effective and often toxic for patients. The PTR1 enzyme, which causes antifolate drug resistance in Leishmania parasites encoded by gene pteridine reductase 1 (ptr1). Since Leishmania lacks pteridine and folate metabolism, it cannot synthesize the pteridine moiety from guanine triphosphate. Therefore, it must produce pteridine using PTR1, an essential part of the salvage pathway that reduces oxidized pteridines. Thus, PTR1 is a good drug-target candidate for anti-Leishmania chemotherapy. The aim of this study was the cloning, expression, and enzymatic assay of the ptr1 gene from Iranian lizard Leishmania as a model for further studies on Leishmania. Methods: Promastigote DNA was extracted from the Iranian lizard Leishmania, and the ptr1 gene was amplified using specific primers. The PCR product was cloned, transformed into Escherichia coli strain JM109, and expressed. The recombinant protein (PTR1 enzyme) was then purified and assayed. Results: ptr1 gene was successfully amplified and cloned into expression vector. Recombinant protein (PTR1 enzyme) was purified using affinity chromatography and confirmed by Western-blot and dot blot using anti-Leishmania major PTR1 antibody and anti-T7 tag monoclonal antibody, respectively.
    [Show full text]
  • The Ubiquitination Enzymes of Leishmania Mexicana
    The ubiquitination enzymes of Leishmania mexicana Rebecca Jayne Burge Doctor of Philosophy University of York Biology October 2020 Abstract Post-translational modifications such as ubiquitination are important for orchestrating the cellular transformations that occur as the Leishmania parasite differentiates between its main morphological forms, the promastigote and amastigote. Although 20 deubiquitinating enzymes (DUBs) have been partially characterised in Leishmania mexicana, little is known about the role of E1 ubiquitin-activating (E1), E2 ubiquitin- conjugating (E2) and E3 ubiquitin ligase (E3) enzymes in this parasite. Using bioinformatic methods, 2 E1, 13 E2 and 79 E3 genes were identified in the L. mexicana genome. Subsequently, bar-seq analysis of 23 E1, E2 and HECT/RBR E3 null mutants generated in promastigotes using CRISPR-Cas9 revealed that the E2s UBC1/CDC34, UBC2 and UEV1 and the HECT E3 ligase HECT2 are required for successful promastigote to amastigote differentiation and UBA1b, UBC9, UBC14, HECT7 and HECT11 are required for normal proliferation during mouse infection. Null mutants could not be generated for the E1 UBA1a or the E2s UBC3, UBC7, UBC12 and UBC13, suggesting these genes are essential in promastigotes. X-ray crystal structure analysis of UBC2 and UEV1, orthologues of human UBE2N and UBE2V1/UBE2V2 respectively, revealed a heterodimer with a highly conserved structure and interface. Furthermore, recombinant L. mexicana UBA1a was found to load ubiquitin onto UBC2, allowing UBC2- UEV1 to form K63-linked di-ubiquitin chains in vitro. UBC2 was also shown to cooperate with human E3s RNF8 and BIRC2 in vitro to form non-K63-linked polyubiquitin chains, but association of UBC2 with UEV1 inhibits this ability.
    [Show full text]
  • Design, Synthesis and Biological Evaluation of Novel Inhibitors of Trypanosoma Brucei Pteridine Reductase 1 Daniel Spinks, Han B
    MED DOI: 10.1002/cmdc.201000450 Design, Synthesis and Biological Evaluation of Novel Inhibitors of Trypanosoma brucei Pteridine Reductase 1 Daniel Spinks, Han B. Ong, Chidochangu P. Mpamhanga, Emma J. Shanks, David A. Robinson, Iain T. Collie, Kevin D. Read, Julie A. Frearson, Paul G. Wyatt, Ruth Brenk, Alan H. Fairlamb, and Ian H. Gilbert*[a] Genetic studies indicate that the enzyme pteridine reductase 1 chemistry and structure-based approaches, we were able to (PTR1) is essential for the survival of the protozoan parasite Try- derive compounds with potent activity against T. brucei PTR1 app m panosoma brucei. Herein, we describe the development and (K i = 7n ), which had high selectivity over both human and optimisation of a novel series of PTR1 inhibitors, based on ben- T. brucei dihydrofolate reductase. Unfortunately, these com- zo[d]imidazol-2-amine derivatives. Data are reported on 33 pounds displayed weak activity against the parasites. Kinetic compounds. This series was initially discovered by a virtual studies and analysis indicate that the main reason for the lack screening campaign (J. Med. Chem., 2009, 52, 4454). The inhibi- of cell potency is due to the compounds having insufficient tors adopted an alternative binding mode to those of the nat- potency against the enzyme, which can be seen from the low m m ural ligands, biopterin and dihydrobiopterin, and classical in- Km to Ki ratio (Km =25 n and Ki = 2.3 n , respectively). hibitors, such as methotrexate. Using both rational medicinal Introduction Human African trypanosomiasis (HAT) is a serious health prob- lem in sub-Saharan Africa, with an estimated 50 000 new infec- tions each year, and over 60 million people in 36 countries are at risk of infection.[1] HAT is a progressive and ultimately fatal disease.
    [Show full text]
  • Developmental Adaptations of Energy and Lipid Metabolism in Trypanosoma Brucei Insect Forms
    Department Biologie I Bereich Genetik Ludwig-Maximilians-Universität München Developmental adaptations of energy and lipid metabolism in Trypanosoma brucei insect forms. Stefan Allmann Dissertation der Fakultät für Biologie, Ludwig-Maximilians-Universität München Eingereicht am 18.09.2014 Erster Gutachter : Prof. Dr. Michael Boshart Biozentrum der Ludwig-Maximilians-Universität München Bereich Genetik Zweiter Gutachter: Prof. Dr. Peter Geigenberger Biozentrum der Ludwig-Maximilians-Universität München Bereich Pflanzenwissenschaften Datum der Abgabe: 18.09.2014 Datum der mündlichen Prüfung: 24.10.2014 Eidesstattliche Erklärung Ich versichere hiermit an Eides statt, dass die vorgelegte Dissertation von mir selbstständig und ohne unerlaubte Hilfe angefertigt wurde. Des Weiteren erkläre ich, dass ich nicht anderweitig ohne Erfolg versucht habe eine Dissertation einzureichen oder mich der Doktorprüfung zu unterziehen. Die folgende Dissertation liegt weder ganz, noch in wesentlichen Teilen einer anderen Prüfungskommission vor. München, 18.09.2014 Statutory declaration I declare that I have authored this thesis independently, that I have not used other than the declared sources/resources. As well I declare, that I have not submitted a dissertation without success and not passed the oral exam. The present dissertation (neither the entire dissertation nor parts) has not been presented to another examination board. Munich, 18.09.2014 III Content Eidesstattliche Erklärung III Statutory declaration III Abbreviations V Publications and Manuscripts Originating from this Thesis VII Contribution to Publications and Manuscripts Presented in this Thesis VIII Summary IX Zusammenfassung X 1. Introduction 11 1.1 Trypanosoma brucei in a nutshell 11 1.2 The parasite’s life cycle 12 1.3 Intermediate and energy metabolism 14 1.4 NADPH balance 17 1.5 Lipid droplets as energy storage 20 2.
    [Show full text]
  • The Influence of Cell Cycle Regulation on Chemotherapy
    International Journal of Molecular Sciences Review The Influence of Cell Cycle Regulation on Chemotherapy Ying Sun 1, Yang Liu 1, Xiaoli Ma 2 and Hao Hu 1,* 1 Institute of Biomedical Materials and Engineering, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, China; [email protected] (Y.S.); [email protected] (Y.L.) 2 Qingdao Institute of Measurement Technology, Qingdao 266000, China; [email protected] * Correspondence: [email protected] Abstract: Cell cycle regulation is orchestrated by a complex network of interactions between proteins, enzymes, cytokines, and cell cycle signaling pathways, and is vital for cell proliferation, growth, and repair. The occurrence, development, and metastasis of tumors are closely related to the cell cycle. Cell cycle regulation can be synergistic with chemotherapy in two aspects: inhibition or promotion. The sensitivity of tumor cells to chemotherapeutic drugs can be improved with the cooperation of cell cycle regulation strategies. This review presented the mechanism of the commonly used chemotherapeutic drugs and the effect of the cell cycle on tumorigenesis and development, and the interaction between chemotherapy and cell cycle regulation in cancer treatment was briefly introduced. The current collaborative strategies of chemotherapy and cell cycle regulation are discussed in detail. Finally, we outline the challenges and perspectives about the improvement of combination strategies for cancer therapy. Keywords: chemotherapy; cell cycle regulation; drug delivery systems; combination chemotherapy; cancer therapy Citation: Sun, Y.; Liu, Y.; Ma, X.; Hu, H. The Influence of Cell Cycle Regulation on Chemotherapy. Int. J. 1. Introduction Mol. Sci. 2021, 22, 6923. https:// Chemotherapy is currently one of the main methods of tumor treatment [1].
    [Show full text]
  • ABSTRACT Title of Dissertation
    ABSTRACT Title of Dissertation: COMPARATIVE TRANSCRIPTOME PROFILING OF HUMAN FORESKIN FIBROBLASTS INFECTED WITH THE SYLVIO AND Y STRAINS OF TRYPANOSOMA CRUZI Genevieve Houston-Ludlam, Doctor of Philosophy, 2016 Dissertation Directed by: Professor Najib M. El-Sayed Department of Cell Biology and Molecular Genetics Trypanosoma cruzi, the causative agent of Chagas Disease, is phylogenetically distributed into nearly identical genetic strains which show divergent clinical presentations including differences in rates of cardiomyopathy in humans, different vector species and transmission cycles, and differential congenital transmission in a mouse model. The population structure of these strains divides into two groups, which are geographically and clinically distinct. The aim of this study was to compare the transcriptome of two strains of T. cruzi, Sylvio vs. Y to identify differences in expression that could account for clinical and biochemical differences. We collected and sequenced RNA from T. cruzi-infected and control Human Foreskin Fibroblasts at three timepoints. Differential expression analysis identified gene expression profiles at different timepoints in Sylvio infections, and between Sylvio and Y infections in both parasite and host. The Sylvio strain parasite and the host response to Sylvio infection largely mirrored the host- pathogen interaction seen in our previous Y strain work. IL-8 was more highly expressed in Sylvio-infected HFFs than in Y-infected HFFs. Comparative transcriptome profiling of human foreskin fibroblasts infected with the Sylvio and Y strains of Trypanosoma cruzi By Genevieve Houston-Ludlam Dissertation submitted to the Faculty of the Graduate School of the University of Maryland, College Park, in partial fulfillment of the requirements for the degree of Doctor of Philosophy 2016 Advisory Committee: Professor Najib M.
    [Show full text]
  • Dihydropteridine Reductase
    John M. Whiteley et uf. : Dihydropteridine reductase Pteridines Vol. 4, 1993, pp. 159-173 Review Dihydropteridine Reductase John M. Whiteley§, Kottayil I. Varughesej:, Nguyen H. Xuong#, David A. Matthews, t and Charles E. Grimshawf §The Scripps Research Institute, La Jolla, CA 92037, USA., #University of California at San Diego, La Jolla, CA 92093-0317, U.SA., tAgouron Pharmaceuticals, Inc., San Diego, CA 92121, USA, and fThe Whittier Institute, La Jolla, CA 92037, USA. (Received August lO, 1993) Summary During the past decade numerous advances have been made in understanding the structure, mechanism and clinical properties of dihydropteridine reductase. An attempt is made here to delineate the current status of this essential enzyme by describing its structural features, its kinetic mechanism, the cloning and expression of both rat and human enzyme forms, the solution of their crystal structures, their classifica­ tion as members of a large family of short chain dehydrogenases, and finally a brief description is included indicating how current molecular biological applications have allowed the clinical definition of the aberrant form of phenylketonuria caused by a defective reductase. Key words: Dihydropteridine reductase, Quinonoid dihydrobiopterin, Crystal structure, Aberrant PKU, Gene expression, Mutagenesis Introduction and history in their heterocyclic nucleus of many centers for protonation, which often influence binding and reac­ Naturally occurring pteridines, which usually con­ tivity. Important metabolic functions of conjugated tain 2-amino and 4-hydroxyl substituents can be sep­ pteridine-mediated biological reactions include the arated into two distinct classes. One class contains one-carbon insertion reactions fundamental to pu­ the pterins of the folic acid series which possess rine biosynthesis (4.
    [Show full text]
  • DNA Topoisomerase I and DNA Gyrase As Targets for TB Therapy, Drug Discov Today (2016), J.Drudis.2016.11.006
    Drug Discovery Today Volume 00, Number 00 November 2016 REVIEWS GENE TO SCREEN DNA topoisomerase I and DNA gyrase as targets for TB therapy Reviews 1,2 1 3 Valakunja Nagaraja , Adwait A. Godbole , Sara R. Henderson and 3 Anthony Maxwell 1 Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India 2 Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India 3 Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK Tuberculosis (TB) is the deadliest bacterial disease in the world. New therapeutic agents are urgently needed to replace existing drugs for which resistance is a significant problem. DNA topoisomerases are well-validated targets for antimicrobial and anticancer chemotherapies. Although bacterial topoisomerase I has yet to be exploited as a target for clinical antibiotics, DNA gyrase has been extensively targeted, including the highly clinically successful fluoroquinolones, which have been utilized in TB therapy. Here, we review the exploitation of topoisomerases as antibacterial targets and summarize progress in developing new agents to target DNA topoisomerase I and DNA gyrase from Mycobacterium tuberculosis. Introduction provides for a certain degree of overlap in their functions. For Although the information content of DNA is essentially indepen- instance, in Escherichia coli, there are four topoisomerases: two dent of how the DNA is knotted or twisted, the access to this type I [topoisomerase (topo) I and topo III] and two type II (DNA information depends on the topology of the DNA. DNA topoi- gyrase and topo IV). In vitro, all four enzymes are capable of DNA somerases are ubiquitous enzymes that maintain the topological relaxation, whereas, in vivo, their roles tend to be more special- homeostasis within the cell during these DNA transaction pro- ized, for example, gyrase introduces negative supercoils, whereas cesses [1–3].
    [Show full text]
  • Dissertation.Pdf
    A Cluster of Antimony Resistance Genes on Chromosome 34 of Leishmania infantum and Their Properties Dissertation with the aim of achieving a doctoral degree at the Faculty of Mathematics, Informatics and Natural Sciences Department of Biology of Universität Hamburg Submitted by Paloma Tejera Nevado 2016 Hamburg This work has been performed from May 2013 to April 2016 in the research group of PD Dr. Joachim Clos at the Bernhard-Nocht-Institute for Tropical Medicine in Hamburg. 1. Evaluator: Prof. Dr. Wilhelm Schäfer Biozentrum Klein Flottbek Abteilung für Molekulare Phytopathologie und Genetik Ohnhorstst. 18, 22609 Hamburg 2. Evaluator: PD Dr. Joachim Clos Bernhard-Nocht-Institut für Tropenmedizin Abteilung für Molekulare Parasitologie Bernhard-Nocht-Straße 74, 20359 Hamburg Day of oral defense: 15th July 2016 Hiermit erkläre ich an Eides statt, dass ich die vorliegende Dissertationsschrift selbst verfasst und keine anderen als die angegebenen Quellen und Hilfsmittel benutzt habe. I hereby declare, on oath, that I have written the present dissertation by my own and have not used other than the acknowledged resources and aids. Hamburg, 2016 Signature Paloma Tejera Nevado Acknowledgements This thesis reflects part of the intensive work done during three years. During this time I have learnt a lot of things at the BNI. I would like to express my sincere gratitude to PD Dr Joachim Clos, who gave me the opportunity to do my doctoral studies in his lab. I would also like to thank my co supervisors at the institute PD Dr Thomas Jacobs and Dr Michael Schreiber and Prof. Dr Wihelm Schäfer at the UHH. I am especially grateful to my family, especially my parents and my sister.
    [Show full text]
  • High Expression of TOP2A Gene Predicted Poor Prognosis of Hepatocellular Carcinoma After Radical Hepatectomy
    992 Original Article High expression of TOP2A gene predicted poor prognosis of hepatocellular carcinoma after radical hepatectomy Hongyu Cai1,2, Xinhua Zhu3, Fei Qian4, Bingfeng Shao2, Yuan Zhou2, Yixin Zhang2, Zhong Chen1,4 1Department of General Surgery, The First Affiliated Hospital of Soochow University, Soochow 215006, China; 2Department of Hepatobiliary Surgery, Nantong Tumor Hospital, Nantong 226361, China; 3Department of Pathological, Affiliated Tumor Hospital of Nantong University, Nantong 226006, China; 4Department of Hepatobiliary Surgery, Affiliated Hospital of Nantong University, Nantong 226001, China Contributions: (I) Conception and design: Z Chen, H Cai; (II) Administrative support: Y Zhang, Y Zhou; (III) Provision of study materials or patients: B Shao; (IV) Collection and assembly of data: H Cai, X Zhu, F Qian; (V) Data analysis and interpretation: H Cai, X Zhu; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors. Correspondence to: Zhong Chen. Department of General Surgery, The First Affiliated Hospital of Soochow University, Soochow 215006, China. Email: [email protected]. Background: Topoisomerase (DNA) II alpha (TOP2A) is the up-regulated gene of the chromosome aggregation pathway. This gene encodes DNA topoisomerase, which can control and change the topological state of DNA during transcription and replication, participate in chromosome agglutination, separation, and relieve stress from kinking. Abnormally high expression of TOP2A is often associated with active cell proliferation. In studies of breast cancer, endometrial cancer, and adrenal cancer, it was found that high expression of TOP2A suggested a poor prognosis. Methods: A total of 15 pairs of fresh hepatocellular carcinoma (HCC) specimens and adjacent tissues were assembled, and the difference of TOP2A mRNA and protein expression level between tumor and adjacent tissues was detected by RT-PCR and Western blotting analysis, respectively.
    [Show full text]
  • One Scaffold, Three Binding Modes: Novel and Selective Pteridine Reductase 1 Inhibitors Derived from Fragment Hits Discovered by Virtual Screening†
    4454 J. Med. Chem. 2009, 52, 4454–4465 DOI: 10.1021/jm900414x One Scaffold, Three Binding Modes: Novel and Selective Pteridine Reductase 1 Inhibitors Derived from Fragment Hits Discovered by Virtual Screening† Chidochangu P. Mpamhanga, Daniel Spinks, Lindsay B. Tulloch, Emma J. Shanks, David A. Robinson, Iain T. Collie, Alan H. Fairlamb, Paul G. Wyatt, Julie A. Frearson, William N. Hunter, Ian H. Gilbert, and Ruth Brenk* Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K. Received March 31, 2009 The enzyme pteridine reductase 1 (PTR1) is a potential target for new compounds to treat human African trypanosomiasis. A virtual screening campaign for fragments inhibiting PTR1 was carried out. Two novel chemical series were identified containing aminobenzothiazole and aminobenzimidazole scaffolds, respectively. One of the hits (2-amino-6-chloro-benzimidazole) was subjected to crystal structure analysis and a high resolution crystal structure in complex with PTR1 was obtained, confirming the predicted binding mode. However, the crystal structures of two analogues (2-amino- benzimidazole and 1-(3,4-dichloro-benzyl)-2-amino-benzimidazole) in complex with PTR1 revealed two alternative binding modes. In these complexes, previously unobserved protein movements and water-mediated protein-ligand contacts occurred, which prohibited a correct prediction of the binding modes. On the basis of the alternative binding mode of 1-(3,4-dichloro-benzyl)-2-amino-benzimidazole, derivatives
    [Show full text]