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Berhe H, Kumar Cinthakunta Sridhar M, Zerihun M, Qvit N. The Potential Use of Peptides in the Fight against Chagas Disease and Leishmaniasis. Pharmaceutics 2024; 16:227. [PMID: 38399281 PMCID: PMC10892537 DOI: 10.3390/pharmaceutics16020227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 12/28/2023] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Chagas disease and leishmaniasis are both neglected tropical diseases that affect millions of people around the world. Leishmaniasis is currently the second most widespread vector-borne parasitic disease after malaria. The World Health Organization records approximately 0.7-1 million newly diagnosed leishmaniasis cases each year, resulting in approximately 20,000-30,000 deaths. Also, 25 million people worldwide are at risk of Chagas disease and an estimated 6 million people are infected with Trypanosoma cruzi. Pentavalent antimonials, amphotericin B, miltefosine, paromomycin, and pentamidine are currently used to treat leishmaniasis. Also, nifurtimox and benznidazole are two drugs currently used to treat Chagas disease. These drugs are associated with toxicity problems such as nephrotoxicity and cardiotoxicity, in addition to resistance problems. As a result, the discovery of novel therapeutic agents has emerged as a top priority and a promising alternative. Overall, there is a need for new and effective treatments for Chagas disease and leishmaniasis, as the current drugs have significant limitations. Peptide-based drugs are attractive due to their high selectiveness, effectiveness, low toxicity, and ease of production. This paper reviews the potential use of peptides in the treatment of Chagas disease and leishmaniasis. Several studies have demonstrated that peptides are effective against Chagas disease and leishmaniasis, suggesting their use in drug therapy for these diseases. Overall, peptides have the potential to be effective therapeutic agents against Chagas disease and leishmaniasis, but more research is needed to fully investigate their potential.
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Affiliation(s)
| | | | | | - Nir Qvit
- The Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Safed 1311502, Israel; (H.B.); (M.K.C.S.); (M.Z.)
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Panecka-Hofman J, Poehner I. Structure and dynamics of pteridine reductase 1: the key phenomena relevant to enzyme function and drug design. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:521-532. [PMID: 37608196 PMCID: PMC10618315 DOI: 10.1007/s00249-023-01677-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 07/08/2023] [Accepted: 07/24/2023] [Indexed: 08/24/2023]
Abstract
Pteridine reductase 1 (PTR1) is a folate and pterin pathway enzyme unique for pathogenic trypanosomatids. As a validated drug target, PTR1 has been the focus of recent research efforts aimed at finding more effective treatments against human parasitic diseases such as leishmaniasis or sleeping sickness. Previous PTR1-centered structural studies highlighted the enzyme characteristics, such as flexible regions around the active site, highly conserved structural waters, and species-specific differences in pocket properties and dynamics, which likely impacts the binding of natural substrates and inhibitors. Furthermore, several aspects of the PTR1 function, such as the substrate inhibition phenomenon and the level of ligand binding cooperativity in the enzyme homotetramer, likely related to the global enzyme dynamics, are poorly known at the molecular level. We postulate that future drug design efforts could greatly benefit from a better understanding of these phenomena through studying both the local and global PTR1 dynamics. This review highlights the key aspects of the PTR1 structure and dynamics relevant to structure-based drug design that could be effectively investigated by modeling approaches. Particular emphasis is given to the perspective of molecular dynamics, what has been accomplished in this area to date, and how modeling could impact the PTR1-targeted drug design in the future.
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Affiliation(s)
- Joanna Panecka-Hofman
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland.
| | - Ina Poehner
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211, Kuopio, Finland
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Jamabo M, Mahlalela M, Edkins AL, Boshoff A. Tackling Sleeping Sickness: Current and Promising Therapeutics and Treatment Strategies. Int J Mol Sci 2023; 24:12529. [PMID: 37569903 PMCID: PMC10420020 DOI: 10.3390/ijms241512529] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/27/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
Human African trypanosomiasis is a neglected tropical disease caused by the extracellular protozoan parasite Trypanosoma brucei, and targeted for eradication by 2030. The COVID-19 pandemic contributed to the lengthening of the proposed time frame for eliminating human African trypanosomiasis as control programs were interrupted. Armed with extensive antigenic variation and the depletion of the B cell population during an infectious cycle, attempts to develop a vaccine have remained unachievable. With the absence of a vaccine, control of the disease has relied heavily on intensive screening measures and the use of drugs. The chemotherapeutics previously available for disease management were plagued by issues such as toxicity, resistance, and difficulty in administration. The approval of the latest and first oral drug, fexinidazole, is a major chemotherapeutic achievement for the treatment of human African trypanosomiasis in the past few decades. Timely and accurate diagnosis is essential for effective treatment, while poor compliance and resistance remain outstanding challenges. Drug discovery is on-going, and herein we review the recent advances in anti-trypanosomal drug discovery, including novel potential drug targets. The numerous challenges associated with disease eradication will also be addressed.
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Affiliation(s)
- Miebaka Jamabo
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| | - Maduma Mahlalela
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| | - Adrienne L. Edkins
- Department of Biochemistry and Microbiology, Biomedical Biotechnology Research Centre (BioBRU), Rhodes University, Makhanda 6139, South Africa;
| | - Aileen Boshoff
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
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4
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Panecka-Hofman J, Poehner I, Wade R. Anti-trypanosomatid structure-based drug design - lessons learned from targeting the folate pathway. Expert Opin Drug Discov 2022; 17:1029-1045. [PMID: 36073204 DOI: 10.1080/17460441.2022.2113776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Trypanosomatidic parasitic infections of humans and animals caused by Trypanosoma brucei, Trypanosoma cruzi, and Leishmania species pose a significant health and economic burden in developing countries. There are few effective and accessible treatments for these diseases, and the existing therapies suffer from problems such as parasite resistance and side effects. Structure-based drug design (SBDD) is one of the strategies that has been applied to discover new compounds targeting trypanosomatid-borne diseases. AREAS COVERED We review the current literature (mostly over the last 5 years, searched in PubMed database on Nov 11th 2021) on the application of structure-based drug design approaches to identify new anti-trypanosomatidic compounds that interfere with a validated target biochemical pathway, the trypanosomatid folate pathway. EXPERT OPINION The application of structure-based drug design approaches to perturb the trypanosomatid folate pathway has successfully provided many new inhibitors with good selectivity profiles, most of which are natural products or their derivatives or have scaffolds of known drugs. However, the inhibitory effect against the target protein(s) often does not translate to anti-parasitic activity. Further progress is hampered by our incomplete understanding of parasite biology and biochemistry, which is necessary to complement SBDD in a multiparameter optimization approach to discovering selective anti-parasitic drugs.
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Affiliation(s)
- Joanna Panecka-Hofman
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5a, 02-097 Warsaw, Poland
| | - Ina Poehner
- School of Pharmacy, University of Eastern Finland, Kuopio, Yliopistonranta 1C, PO Box 1627, FI-70211 Kuopio, Finland
| | - Rebecca Wade
- Center for Molecular Biology (ZMBH), Heidelberg University, Im Neuenheimer Feld 282, Heidelberg 69120, Germany.,Heidelberg Institute for Theoretical Studies (HITS), Schloß-Wolfsbrunnenweg 35, Heidelberg 69118, Germany.,DKFZ-ZMBH Alliance and Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Im Neuenheimer Feld 205, Heidelberg 69120, Germany
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Examination of multiple Trypanosoma cruzi targets in a new drug discovery approach for Chagas disease. Bioorg Med Chem 2022; 58:116577. [DOI: 10.1016/j.bmc.2021.116577] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 12/21/2022]
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Tassone G, Landi G, Linciano P, Francesconi V, Tonelli M, Tagliazucchi L, Costi MP, Mangani S, Pozzi C. Evidence of Pyrimethamine and Cycloguanil Analogues as Dual Inhibitors of Trypanosoma brucei Pteridine Reductase and Dihydrofolate Reductase. Pharmaceuticals (Basel) 2021; 14:636. [PMID: 34209148 PMCID: PMC8308740 DOI: 10.3390/ph14070636] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/15/2022] Open
Abstract
Trypanosoma and Leishmania parasites are the etiological agents of various threatening neglected tropical diseases (NTDs), including human African trypanosomiasis (HAT), Chagas disease, and various types of leishmaniasis. Recently, meaningful progresses in the treatment of HAT, due to Trypanosoma brucei (Tb), have been achieved by the introduction of fexinidazole and the combination therapy eflornithine-nifurtimox. Nevertheless, due to drug resistance issues and the exitance of animal reservoirs, the development of new NTD treatments is still required. For this purpose, we explored the combined targeting of two key folate enzymes, dihydrofolate reductase (DHFR) and pteridine reductase 1 (PTR1). We formerly showed that the TbDHFR inhibitor cycloguanil (CYC) also targets TbPTR1, although with reduced affinity. Here, we explored a small library of CYC analogues to understand how their substitution pattern affects the inhibition of both TbPTR1 and TbDHFR. Some novel structural features responsible for an improved, but preferential, ability of CYC analogues to target TbPTR1 were disclosed. Furthermore, we showed that the known drug pyrimethamine (PYR) effectively targets both enzymes, also unveiling its binding mode to TbPTR1. The structural comparison between PYR and CYC binding modes to TbPTR1 and TbDHFR provided key insights for the future design of dual inhibitors for HAT therapy.
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Affiliation(s)
- Giusy Tassone
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018–2022, University of Siena, via Aldo Moro 2, 53100 Siena, Italy; (G.T.); (G.L.); (S.M.)
| | - Giacomo Landi
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018–2022, University of Siena, via Aldo Moro 2, 53100 Siena, Italy; (G.T.); (G.L.); (S.M.)
| | - Pasquale Linciano
- Department of Life Science, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy; (P.L.); (L.T.); (M.P.C.)
| | - Valeria Francesconi
- Department of Pharmacy, University of Genoa, Viale Benedetto XV n.3, 16132 Genoa, Italy; (V.F.); (M.T.)
| | - Michele Tonelli
- Department of Pharmacy, University of Genoa, Viale Benedetto XV n.3, 16132 Genoa, Italy; (V.F.); (M.T.)
| | - Lorenzo Tagliazucchi
- Department of Life Science, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy; (P.L.); (L.T.); (M.P.C.)
| | - Maria Paola Costi
- Department of Life Science, University of Modena and Reggio Emilia, via Campi 103, 41125 Modena, Italy; (P.L.); (L.T.); (M.P.C.)
| | - Stefano Mangani
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018–2022, University of Siena, via Aldo Moro 2, 53100 Siena, Italy; (G.T.); (G.L.); (S.M.)
| | - Cecilia Pozzi
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018–2022, University of Siena, via Aldo Moro 2, 53100 Siena, Italy; (G.T.); (G.L.); (S.M.)
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Labine M, DePledge L, Feirer N, Greenwich J, Fuqua C, Allen KD. Enzymatic and Mutational Analysis of the PruA Pteridine Reductase Required for Pterin-Dependent Control of Biofilm Formation in Agrobacterium tumefaciens. J Bacteriol 2020; 202:JB.00098-20. [PMID: 32482721 PMCID: PMC8404713 DOI: 10.1128/jb.00098-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/22/2020] [Indexed: 11/20/2022] Open
Abstract
Pterins are ubiquitous biomolecules with diverse functions including roles as cofactors, pigments, and redox mediators. Recently, a novel pterin-dependent signaling pathway that controls biofilm formation was identified in the plant pathogen, Agrobacterium tumefaciens A key player in this pathway is a pteridine reductase termed PruA, where its enzymatic activity has been shown to control surface attachment and limit biofilm formation. Here, we biochemically characterize PruA to investigate the catalytic properties and substrate specificity of this pteridine reductase. PruA demonstrates maximal catalytic efficiency with dihydrobiopterin and comparable activities with the stereoisomers dihydromonapterin and dihydroneopterin. Since A. tumefaciens does not synthesize or utilize biopterins, the likely physiological substrate is dihydromonapterin or dihydroneopterin, or both. Notably, PruA does not exhibit pteridine reductase activity with dihydrofolate or fully oxidized pterins. Site-directed mutagenesis studies of a conserved tyrosine residue, the key component of a putative catalytic triad, indicate that this tyrosine is not directly involved in PruA catalysis but may be important for substrate or cofactor binding. Additionally, mutagenesis of the arginine residue in the N-terminal TGX3RXG motif significantly reduces the catalytic efficiency of PruA, supporting its proposed role in pterin binding and catalysis. Finally, we report the enzymatic characterization of PruA homologs from Pseudomonas aeruginosa and Brucella abortus, thus expanding the roles and potential significance of pteridine reductases in diverse bacteria.Importance Biofilms are complex multicellular communities that are formed by diverse bacteria. In the plant pathogen, Agrobacterium tumefaciens, the transition from a free-living motile state to a non-motile biofilm state is governed by a novel signaling pathway involving small molecules called pterins. The involvement of pterins in biofilm formation is unexpected and prompts many questions about the molecular details of this pathway. This work biochemically characterizes the PruA pteridine reductase involved in the signaling pathway to reveal its enzymatic properties and substrate preference, thus providing important insight into pterin biosynthesis and its role in A. tumefaciens biofilm control. Additionally, the enzymatic characteristics of related pteridine reductases from mammalian pathogens are examined to uncover potential roles of these enzymes in other bacteria.
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Affiliation(s)
- Monica Labine
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Lisa DePledge
- Department of Chemistry and Biochemistry, Gonzaga University, Spokane, WA, USA
| | - Nathan Feirer
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | | | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Kylie D Allen
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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8
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Kimuda MP, Laming D, Hoppe HC, Tastan Bishop Ö. Identification of Novel Potential Inhibitors of Pteridine Reductase 1 in Trypanosoma brucei via Computational Structure-Based Approaches and in Vitro Inhibition Assays. Molecules 2019; 24:molecules24010142. [PMID: 30609681 PMCID: PMC6337619 DOI: 10.3390/molecules24010142] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/20/2018] [Accepted: 12/24/2018] [Indexed: 11/16/2022] Open
Abstract
Pteridine reductase 1 (PTR1) is a trypanosomatid multifunctional enzyme that provides a mechanism for escape of dihydrofolate reductase (DHFR) inhibition. This is because PTR1 can reduce pterins and folates. Trypanosomes require folates and pterins for survival and are unable to synthesize them de novo. Currently there are no anti-folate based Human African Trypanosomiasis (HAT) chemotherapeutics in use. Thus, successful dual inhibition of Trypanosoma brucei dihydrofolate reductase (TbDHFR) and Trypanosoma brucei pteridine reductase 1 (TbPTR1) has implications in the exploitation of anti-folates. We carried out molecular docking of a ligand library of 5742 compounds against TbPTR1 and identified 18 compounds showing promising binding modes. The protein-ligand complexes were subjected to molecular dynamics to characterize their molecular interactions and energetics, followed by in vitro testing. In this study, we identified five compounds which showed low micromolar Trypanosome growth inhibition in in vitro experiments that might be acting by inhibition of TbPTR1. Compounds RUBi004, RUBi007, RUBi014, and RUBi018 displayed moderate to strong antagonism (mutual reduction in potency) when used in combination with the known TbDHFR inhibitor, WR99210. This gave an indication that the compounds might inhibit both TbPTR1 and TbDHFR. RUBi016 showed an additive effect in the isobologram assay. Overall, our results provide a basis for scaffold optimization for further studies in the development of HAT anti-folates.
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Affiliation(s)
- Magambo Phillip Kimuda
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
- College of Veterinary Medicine, Animal Resources and Biosecurity (COVAB), Makerere University, P.O. Box 7062, Kampala 00256, Uganda.
| | - Dustin Laming
- Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa.
- Centre for Chemico- and Biomedicinal Research, Rhodes University, Grahamstown 6140, South Africa.
| | - Heinrich C Hoppe
- Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa.
- Centre for Chemico- and Biomedicinal Research, Rhodes University, Grahamstown 6140, South Africa.
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
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Panecka-Hofman J, Pöhner I, Spyrakis F, Zeppelin T, Di Pisa F, Dello Iacono L, Bonucci A, Quotadamo A, Venturelli A, Mangani S, Costi M, Wade RC. Comparative mapping of on-targets and off-targets for the discovery of anti-trypanosomatid folate pathway inhibitors. Biochim Biophys Acta Gen Subj 2017; 1861:3215-3230. [DOI: 10.1016/j.bbagen.2017.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 09/11/2017] [Accepted: 09/13/2017] [Indexed: 01/06/2023]
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Jedwabny W, Panecka-Hofman J, Dyguda-Kazimierowicz E, Wade RC, Sokalski WA. Application of a simple quantum chemical approach to ligand fragment scoring for Trypanosoma brucei pteridine reductase 1 inhibition. J Comput Aided Mol Des 2017; 31:715-728. [PMID: 28688090 PMCID: PMC5570812 DOI: 10.1007/s10822-017-0035-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 06/16/2017] [Indexed: 11/15/2022]
Abstract
There is a need for improved and generally applicable scoring functions for fragment-based approaches to ligand design. Here, we evaluate the performance of a computationally efficient model for inhibitory activity estimation, which is composed only of multipole electrostatic energy and dispersion energy terms that approximate long-range ab initio quantum mechanical interaction energies. We find that computed energies correlate well with inhibitory activity for a compound series with varying substituents targeting two subpockets of the binding site of Trypanosoma brucei pteridine reductase 1. For one subpocket, we find that the model is more predictive for inhibitory activity than the ab initio interaction energy calculated at the MP2 level. Furthermore, the model is found to outperform a commonly used empirical scoring method. Finally, we show that the results for the two subpockets can be combined, which suggests that this simple nonempirical scoring function could be applied in fragment–based drug design.
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Affiliation(s)
- Wiktoria Jedwabny
- Department of Chemistry, Wrocław University of Science and Technology, Wrocław, Poland
| | - Joanna Panecka-Hofman
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany.,Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | | | - Rebecca C Wade
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg, Germany.,Center for Molecular Biology (ZMBH), DKFZ-ZMBH Alliance, Heidelberg University, Heidelberg, Germany.,Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
| | - W Andrzej Sokalski
- Department of Chemistry, Wrocław University of Science and Technology, Wrocław, Poland
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Berná L, Chiribao ML, Greif G, Rodriguez M, Alvarez-Valin F, Robello C. Transcriptomic analysis reveals metabolic switches and surface remodeling as key processes for stage transition in Trypanosoma cruzi. PeerJ 2017; 5:e3017. [PMID: 28286708 PMCID: PMC5345387 DOI: 10.7717/peerj.3017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 01/23/2017] [Indexed: 01/12/2023] Open
Abstract
American trypanosomiasis is a chronic and endemic disease which affects millions of people. Trypanosoma cruzi, its causative agent, has a life cycle that involves complex morphological and functional transitions, as well as a variety of environmental conditions. This requires a tight regulation of gene expression, which is achieved mainly by post-transcriptional regulation. In this work we conducted an RNAseq analysis of the three major life cycle stages of T. cruzi: amastigotes, epimastigotes and trypomastigotes. This analysis allowed us to delineate specific transcriptomic profiling for each stage, and also to identify those biological processes of major relevance in each state. Stage specific expression profiling evidenced the plasticity of T. cruzi to adapt quickly to different conditions, with particular focus on membrane remodeling and metabolic shifts along the life cycle. Epimastigotes, which replicate in the gut of insect vectors, showed higher expression of genes related to energy metabolism, mainly Krebs cycle, respiratory chain and oxidative phosphorylation related genes, and anabolism related genes associated to nucleotide and steroid biosynthesis; also, a general down-regulation of surface glycoprotein coding genes was seen at this stage. Trypomastigotes, living extracellularly in the bloodstream of mammals, express a plethora of surface proteins and signaling genes involved in invasion and evasion of immune response. Amastigotes mostly express membrane transporters and genes involved in regulation of cell cycle, and also express a specific subset of surface glycoprotein coding genes. In addition, these results allowed us to improve the annotation of the Dm28c genome, identifying new ORFs and set the stage for construction of networks of co-expression, which can give clues about coded proteins of unknown functions.
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Affiliation(s)
- Luisa Berná
- Unidad de Biología Molecular, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Maria Laura Chiribao
- Unidad de Biología Molecular, Institut Pasteur de Montevideo, Montevideo, Uruguay.,Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Gonzalo Greif
- Unidad de Biología Molecular, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Matias Rodriguez
- Sección Biomatemática, Unidad de Genómica Evolutiva, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Fernando Alvarez-Valin
- Sección Biomatemática, Unidad de Genómica Evolutiva, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Carlos Robello
- Unidad de Biología Molecular, Institut Pasteur de Montevideo, Montevideo, Uruguay.,Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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de Souza Moreira D, Ferreira RF, Murta SMF. Molecular characterization and functional analysis of pteridine reductase in wild-type and antimony-resistant Leishmania lines. Exp Parasitol 2015; 160:60-6. [PMID: 26689884 DOI: 10.1016/j.exppara.2015.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/21/2015] [Accepted: 12/09/2015] [Indexed: 01/24/2023]
Abstract
Pteridine reductase (PTR1) is an NADPH-dependent reductase that participates in the salvage of pteridines, which are essential to maintain growth of Leishmania. In this study, we performed the molecular characterization of ptr1 gene in wild-type (WTS) and SbIII-resistant (SbR) lines from Leishmania guyanensis (Lg), Leishmania amazonensis (La), Leishmania braziliensis (Lb) and Leishmania infantum (Li), evaluating the chromosomal location, mRNA levels of the ptr1 gene and PTR1 protein expression. PFGE results showed that the ptr1 gene is located in a 797 kb chromosomal band in all Leishmania lines analyzed. Interestingly, an additional chromosomal band of 1070 kb was observed only in LbSbR line. Northern blot results showed that the levels of ptr1 mRNA are increased in the LgSbR, LaSbR and LbSbR lines. Western blot assays using the polyclonal anti-LmPTR1 antibody demonstrated that PTR1 protein is more expressed in the LgSbR, LaSbR and LbSbR lines compared to their respective WTS counterparts. Nevertheless, no difference in the level of mRNA and protein was observed between the LiWTS and LiSbR lines. Functional analysis of PTR1 enzyme was performed to determine whether the overexpression of ptr1 gene in the WTS L. braziliensis and L. infantum lines would change the SbIII-resistance phenotype of transfected parasites. Western blot results showed that the expression level of PTR1 protein was increased in the transfected parasites compared to the non-transfected ones. IC50 analysis revealed that the overexpression of ptr1 gene in the WTS L. braziliensis line increased 2-fold the SbIII-resistance phenotype compared to the non-transfected counterpart. Furthermore, the overexpression of ptr1 gene in the WTS L. infantum line did not change the SbIII-resistance phenotype. These results suggest that the PTR1 enzyme may be implicated in the SbIII-resistance phenotype in L. braziliensis line.
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Affiliation(s)
- Douglas de Souza Moreira
- Laboratório de Parasitologia Celular e Molecular, Centro de Pesquisas René Rachou CPqRR/Fiocruz, Av. Augusto de Lima 1715, CEP 30190-002, Belo Horizonte, MG, Brazil
| | - Rafael Fernandes Ferreira
- Laboratório de Parasitologia Celular e Molecular, Centro de Pesquisas René Rachou CPqRR/Fiocruz, Av. Augusto de Lima 1715, CEP 30190-002, Belo Horizonte, MG, Brazil
| | - Silvane M F Murta
- Laboratório de Parasitologia Celular e Molecular, Centro de Pesquisas René Rachou CPqRR/Fiocruz, Av. Augusto de Lima 1715, CEP 30190-002, Belo Horizonte, MG, Brazil.
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Mendoza-Martínez C, Correa-Basurto J, Nieto-Meneses R, Márquez-Navarro A, Aguilar-Suárez R, Montero-Cortes MD, Nogueda-Torres B, Suárez-Contreras E, Galindo-Sevilla N, Rojas-Rojas Á, Rodriguez-Lezama A, Hernández-Luis F. Design, synthesis and biological evaluation of quinazoline derivatives as anti-trypanosomatid and anti-plasmodial agents. Eur J Med Chem 2015; 96:296-307. [PMID: 25899334 DOI: 10.1016/j.ejmech.2015.04.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 04/10/2015] [Accepted: 04/11/2015] [Indexed: 11/24/2022]
Abstract
In this paper, the design, synthesis and biological evaluation of a set of quinazoline-2,4,6-triamine derivatives (1-9) as trypanocidal, antileishmanial and antiplasmodial agents are explained. The compounds were rationalized basing on docking studies of the dihydrofolate reductase (DHFR from Trypanosoma cruzi, Leishmania major and Plasmodium vivax) and pteridin reductase (PTR from T. cruzi and L. major) structures. All compounds were in vitro screened against both bloodstream trypomastigotes of T. cruzi (NINOA and INC-5 strains) and promatigotes of Leishmania mexicana (MHOM/BZ/61/M379 strain), and also for cytotoxicity using Vero cell line. Against T. cruzi, three compounds (5, 6 and 8) were the most effective showing a better activity profile than nifurtimox and benznidazole (reference drugs). Against L. mexicana, four compounds (5, 6, 8, and 9) exhibited the highest activity, even than glucantime (reference drug). In the cytotoxicity assay, protozoa were more susceptible than Vero cells. In vivo Plasmodium berghei assay (ANKA strain), the compounds 1, 5, 6 and 8 showed a more comparable activity than chloroquine and pyrimethamine (reference drugs) when they were administrated by the oral route. The antiprotozoal activity of these substances, endowed with redox properties, represented a good starting point for a medicinal chemistry program aiming for chemotherapy of Chagas' disease, leishmaniosis and malaria.
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Affiliation(s)
- César Mendoza-Martínez
- Programa de Maestría y Doctorado en Ciencias Químicas, UNAM, México, DF 04510, Mexico; Facultad de Química, Departamento de Farmacia, UNAM, México, DF 04510, Mexico
| | - José Correa-Basurto
- Escuela Superior de Medicina, Laboratorio de Modelado Molecular y Bioinformática de la SEPI, IPN, México, DF 11340, Mexico
| | - Rocío Nieto-Meneses
- Escuela Nacional de Ciencias Biológicas, Departamento de Parasitología, IPN, México, DF 11340, Mexico
| | - Adrián Márquez-Navarro
- Escuela Nacional de Ciencias Biológicas, Departamento de Parasitología, IPN, México, DF 11340, Mexico
| | - Rocío Aguilar-Suárez
- Escuela Nacional de Ciencias Biológicas, Departamento de Parasitología, IPN, México, DF 11340, Mexico
| | | | - Benjamín Nogueda-Torres
- Escuela Nacional de Ciencias Biológicas, Departamento de Parasitología, IPN, México, DF 11340, Mexico
| | - Erick Suárez-Contreras
- Escuela Nacional de Ciencias Biológicas, Departamento de Parasitología, IPN, México, DF 11340, Mexico
| | - Norma Galindo-Sevilla
- Departamento de Infectología, Instituto Nacional de Perinatología, México, DF 11000, Mexico
| | | | | | - Francisco Hernández-Luis
- Programa de Maestría y Doctorado en Ciencias Químicas, UNAM, México, DF 04510, Mexico; Facultad de Química, Departamento de Farmacia, UNAM, México, DF 04510, Mexico.
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14
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Caradonna KL, Engel JC, Jacobi D, Lee CH, Burleigh BA. Host metabolism regulates intracellular growth of Trypanosoma cruzi. Cell Host Microbe 2013; 13:108-17. [PMID: 23332160 DOI: 10.1016/j.chom.2012.11.011] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/08/2012] [Accepted: 11/12/2012] [Indexed: 11/15/2022]
Abstract
Metabolic coupling of intracellular pathogens with host cells is essential for successful colonization of the host. Establishment of intracellular infection by the protozoan Trypanosoma cruzi leads to the development of human Chagas' disease, yet the functional contributions of the host cell toward the infection process remain poorly characterized. Here, a genome-scale functional screen identified interconnected metabolic networks centered around host energy production, nucleotide metabolism, pteridine biosynthesis, and fatty acid oxidation as key processes that fuel intracellular T. cruzi growth. Additionally, the host kinase Akt, which plays essential roles in various cellular processes, was critical for parasite replication. Targeted perturbations in these host metabolic pathways or Akt-dependent signaling pathways modulated the parasite's replicative capacity, highlighting the adaptability of this intracellular pathogen to changing conditions in the host. These findings identify key cellular process regulating intracellular T. cruzi growth and illuminate the potential to leverage host pathways to limit T. cruzi infection.
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Affiliation(s)
- Kacey L Caradonna
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, 665 Huntington Avenue, Building I, Room 817, Boston, MA 02115, USA
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15
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16
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Ferrari S, Morandi F, Motiejunas D, Nerini E, Henrich S, Luciani R, Venturelli A, Lazzari S, Calò S, Gupta S, Hannaert V, Michels PAM, Wade RC, Costi MP. Virtual Screening Identification of Nonfolate Compounds, Including a CNS Drug, as Antiparasitic Agents Inhibiting Pteridine Reductase. J Med Chem 2010; 54:211-21. [DOI: 10.1021/jm1010572] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stefania Ferrari
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Federica Morandi
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Domantas Motiejunas
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Erika Nerini
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
- Heidelberg Institute for Theoretical Studies (HITS) gGmbH, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - Stefan Henrich
- Heidelberg Institute for Theoretical Studies (HITS) gGmbH, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - Rosaria Luciani
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Alberto Venturelli
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Sandra Lazzari
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Samuele Calò
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Shreedhara Gupta
- Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Université catholique de Louvain, Avenue Hippocrate 74, B-1200 Brussels, Belgium
| | - Veronique Hannaert
- Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Université catholique de Louvain, Avenue Hippocrate 74, B-1200 Brussels, Belgium
| | - Paul A. M. Michels
- Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Université catholique de Louvain, Avenue Hippocrate 74, B-1200 Brussels, Belgium
| | - Rebecca C. Wade
- Heidelberg Institute for Theoretical Studies (HITS) gGmbH, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - M. Paola Costi
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
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17
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Regulation of CD8+ T cell responses to infection with parasitic protozoa. Exp Parasitol 2010; 126:318-25. [PMID: 20493842 DOI: 10.1016/j.exppara.2010.05.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 04/05/2010] [Accepted: 05/15/2010] [Indexed: 11/24/2022]
Abstract
There are over 10,000 species of parasitic protozoa, a subset of which can cause considerable disease in humans. Here we examine in detail the complex immune response generated during infection with a subset of these parasites: Trypanosoma cruzi, Leishmania sp., Toxoplasma gondii, and Plasmodium sp. While these particular species perhaps represent the most studied parasites in terms of understanding how T cells function during infection, it is clear that the lessons learned from this body of work are also relevant to the other protozoa known to induce a CD8(+) T cell response. This review will highlight some of the key studies that established that CD8(+) T cells play a major role in protective immunity to protozoa, the factors that promote the generation as well as maintenance of the CD8(+) T cell response during these infections, and draw attention to some of the gaps in our knowledge. Moreover, the development of new tools, including MHC-Class I tetramer reagents and the use of TCR transgenic mice or genetically modified parasites, has provided a better appreciation of how parasite specific CD8(+) T cell responses are initiated and new insights into their phenotypic plasticity.
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18
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Tulloch LB, Martini VP, Iulek J, Huggan JK, Lee JH, Gibson CL, Smith TK, Suckling CJ, Hunter WN. Structure-based design of pteridine reductase inhibitors targeting African sleeping sickness and the leishmaniases. J Med Chem 2010; 53:221-9. [PMID: 19916554 PMCID: PMC2804273 DOI: 10.1021/jm901059x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Pteridine reductase (PTR1) is a target for drug development against Trypanosoma and Leishmania species, parasites that cause serious tropical diseases and for which therapies are inadequate. We adopted a structure-based approach to the design of novel PTR1 inhibitors based on three molecular scaffolds. A series of compounds, most newly synthesized, were identified as inhibitors with PTR1-species specific properties explained by structural differences between the T. brucei and L. major enzymes. The most potent inhibitors target T. brucei PTR1, and two compounds displayed antiparasite activity against the bloodstream form of the parasite. PTR1 contributes to antifolate drug resistance by providing a molecular bypass of dihydrofolate reductase (DHFR) inhibition. Therefore, combining PTR1 and DHFR inhibitors might improve therapeutic efficacy. We tested two new compounds with known DHFR inhibitors. A synergistic effect was observed for one particular combination highlighting the potential of such an approach for treatment of African sleeping sickness.
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Affiliation(s)
- Lindsay B Tulloch
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD15EH, UK
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19
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Shanks EJ, Ong HB, Robinson DA, Thompson S, Sienkiewicz N, Fairlamb AH, Frearson JA. Development and validation of a cytochrome c-coupled assay for pteridine reductase 1 and dihydrofolate reductase. Anal Biochem 2010; 396:194-203. [PMID: 19748480 PMCID: PMC2789237 DOI: 10.1016/j.ab.2009.09.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 09/04/2009] [Accepted: 09/07/2009] [Indexed: 11/19/2022]
Abstract
Activity of the pterin- and folate-salvaging enzymes pteridine reductase 1 (PTR1) and dihydrofolate reductase-thymidylate synthetase (DHFR-TS) is commonly measured as a decrease in absorbance at 340 nm, corresponding to oxidation of nicotinamide adenine dinucleotide phosphate (NADPH). Although this assay has been adequate to study the biology of these enzymes, it is not amenable to support any degree of routine inhibitor assessment because its restricted linearity is incompatible with enhanced throughput microtiter plate screening. In this article, we report the development and validation of a nonenzymatically coupled screening assay in which the product of the enzymatic reaction reduces cytochrome c, causing an increase in absorbance at 550 nm. We demonstrate this assay to be robust and accurate, and we describe its utility in supporting a structure-based design, small-molecule inhibitor campaign against Trypanosoma brucei PTR1 and DHFR-TS.
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Affiliation(s)
| | | | | | | | | | | | - Julie A. Frearson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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20
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Chitnumsub P, Yuvaniyama J, Chahomchuen T, Vilaivan T, Yuthavong Y. Crystallization and preliminary crystallographic studies of dihydrofolate reductase-thymidylate synthase from Trypanosoma cruzi, the Chagas disease pathogen. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:1175-8. [PMID: 19923744 PMCID: PMC2777052 DOI: 10.1107/s1744309109041979] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 10/13/2009] [Indexed: 11/10/2022]
Abstract
Trypanosoma cruzi dihydrofolate reductase-thymidylate synthase (TcDHFR-TS) was crystallized in complexes with the dihydrotriazine-based or quinazoline-based antifolates C-448, cycloguanil (CYC) and Q-8 in order to gain insight into the interactions of this DHFR enzyme with classical and novel inhibitors. The TcDHFR-TS-C-448-NDP-dUMP crystal belonged to space group C222(1) with two molecules per asymmetric unit and diffracted to 2.37 angstrom resolution. The TcDHFR-TS-CYC, TcDHFR-TS-CYC-NDP and TcDHFR-TS-Q-8-NDP crystals belonged to space group P2(1) with four molecules per asymmetric unit and diffracted to 2.1, 2.6 and 2.8 angstrom resolution, respectively. Crystals belonging to the two different space groups were suitable for structure determination.
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Affiliation(s)
- Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand.
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21
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Discovery of potent pteridine reductase inhibitors to guide antiparasite drug development. Proc Natl Acad Sci U S A 2008; 105:1448-53. [PMID: 18245389 DOI: 10.1073/pnas.0704384105] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pteridine reductase (PTR1) is essential for salvage of pterins by parasitic trypanosomatids and is a target for the development of improved therapies. To identify inhibitors of Leishmania major and Trypanosoma cruzi PTR1, we combined a rapid-screening strategy using a folate-based library with structure-based design. Assays were carried out against folate-dependent enzymes including PTR1, dihydrofolate reductase (DHFR), and thymidylate synthase. Affinity profiling determined selectivity and specificity of a series of quinoxaline and 2,4-diaminopteridine derivatives, and nine compounds showed greater activity against parasite enzymes compared with human enzymes. Compound 6a displayed a K(i) of 100 nM toward LmPTR1, and the crystal structure of the LmPTR1:NADPH:6a ternary complex revealed a substrate-like binding mode distinct from that previously observed for similar compounds. A second round of design, synthesis, and assay produced a compound (6b) with a significantly improved K(i) (37 nM) against LmPTR1, and the structure of this complex was also determined. Biological evaluation of selected inhibitors was performed against the extracellular forms of T. cruzi and L. major, both wild-type and overexpressing PTR1 lines, as a model for PTR1-driven antifolate drug resistance and the intracellular form of T. cruzi. An additive profile was observed when PTR1 inhibitors were used in combination with known DHFR inhibitors, and a reduction in toxicity of treatment was observed with respect to administration of a DHFR inhibitor alone. The successful combination of antifolates targeting two enzymes indicates high potential for such an approach in the development of previously undescribed antiparasitic drugs.
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22
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Piñeyro MD, Parodi-Talice A, Arcari T, Robello C. Peroxiredoxins from Trypanosoma cruzi: virulence factors and drug targets for treatment of Chagas disease? Gene 2007; 408:45-50. [PMID: 18022330 DOI: 10.1016/j.gene.2007.10.014] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 10/10/2007] [Accepted: 10/11/2007] [Indexed: 11/17/2022]
Abstract
Cytosolic and mitochondrial Trypanosoma cruzi tryparedoxin peroxidases belong to the family of 2-Cys peroxiredoxins. These enzymes play an essential role as antioxidants by their peroxidase and peroxynitrite reductase activities. TXNPx are key components of the trypanosomatid peroxide detoxification pathways. The aim of this work was to determine the role of TXNPx as virulence factors in the parasite, and whether these enzymes are good candidates for drug design. We observed that peroxiredoxins are not highly abundant proteins expressed at similar levels throughout the T. cruzi life cycle. In order to study the role of c-TXNPx and m-TXNPx in invasion and infectivity, parasites overexpressing TXNPx were produced, and infection experiments were carried out using phagocytic and non-phagocytic cells. Parasites overexpressing peroxiredoxins showed a significant increase in infectivity with respect to the control ones. The results presented in this work point out that the T. cruzi peroxiredoxins are important in survival, replication and differentiation of T. cruzi and could constitute virulence factors. Moreover, their expression in the infective forms of the life cycle and their low intracellular concentration make them good candidates to become targets for drug design.
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Affiliation(s)
- María Dolores Piñeyro
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Gral Flores 2125, 11800, Montevideo, Uruguay
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23
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Papadopoulou B, Kündig C, Singh A, Ouellette M. Drug resistance in Leishmania: similarities and differences to other organisms. Drug Resist Updat 2007; 1:266-78. [PMID: 16904409 DOI: 10.1016/s1368-7646(98)80007-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/1998] [Revised: 06/19/1998] [Accepted: 06/19/1998] [Indexed: 11/28/2022]
Abstract
The main line of defense available against parasitic protozoa is chemotherapy. Drug resistance has emerged however, as a primary obstacle to the successful treatment and control of parasitic diseases. Leishmania spp., the causative agents of leishmaniasis, have served as a useful model for studying mechanisms of drug resistance in vitro. Antimonials and amphotericin B are the first line drugs to treat Leishmania followed by pentamidine and a number of other drugs. Parasites resistant against all these classes of drugs have been selected under laboratory conditions. A multiplicity of resistance mechanisms has been detected, the most prevalent being gene amplification and transport mutations. With the tools now available, it should be possible to elucidate the mechanisms that govern drug resistance in field isolates and develop more effective chemotherapeutic agents.
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Affiliation(s)
- B Papadopoulou
- Centre de Recherche en Infectiologie du Centre de Recherche du CHUL et Départment de Biologie Médicale, Division de Microbiologie, Faculté de Médecine, Université Laval, Québec, Canada GIV 4G2.
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24
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Pérez-Díaz L, Duhagon MA, Smircich P, Sotelo-Silveira J, Robello C, Krieger MA, Goldenberg S, Williams N, Dallagiovanna B, Garat B. Trypanosoma cruzi: molecular characterization of an RNA binding protein differentially expressed in the parasite life cycle. Exp Parasitol 2007; 117:99-105. [PMID: 17475252 PMCID: PMC2020836 DOI: 10.1016/j.exppara.2007.03.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Revised: 03/02/2007] [Accepted: 03/14/2007] [Indexed: 12/18/2022]
Abstract
Molecular studies have shown several peculiarities in the regulatory mechanisms of gene expression in trypanosomatids. Protein coding genes are organized in long polycistronic units that seem to be constitutively transcribed. Therefore, post-transcriptional regulation of gene expression is considered to be the main point for control of transcript abundance and functionality. Here we describe the characterization of a 17 kDa RNA-binding protein from Trypanosoma cruzi (TcRBP19) containing an RNA recognition motive (RRM). This protein is coded by a single copy gene located in a high molecular weight chromosome of T. cruzi. Orthologous genes are present in the TriTryp genomes. TcRBP19 shows target selectivity since among the different homoribopolymers it preferentially binds polyC. TcRBP19 is a low expression protein only barely detected at the amastigote stage localizing in a diffuse pattern in the cytoplasm.
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Affiliation(s)
- Leticia Pérez-Díaz
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
| | - María Ana Duhagon
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
| | - Pablo Smircich
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
| | - José Sotelo-Silveira
- Departamento de Biología Celular y Molecular, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
- Departamento de Neurobiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable Avda Italia 3318, Montevideo, Uruguay
| | - Carlos Robello
- Departamento de Bioquímica, Facultad de Medicina, Gral Flores 2125, 11800, Montevideo, Uruguay
| | - Marco Aurelio Krieger
- Instituto de Biología Molecular do Paraná, Rua Profesor Algacyr Munhoz Mader 3775, Curitiba 81350-010, Brazil
| | - Samuel Goldenberg
- Instituto de Biología Molecular do Paraná, Rua Profesor Algacyr Munhoz Mader 3775, Curitiba 81350-010, Brazil
| | - Noreen Williams
- Dept. of Microbiology and Immunology. 253 Biomedical Research Building. University at Buffalo. Buffalo 14214, NY. USA
| | - Bruno Dallagiovanna
- Instituto de Biología Molecular do Paraná, Rua Profesor Algacyr Munhoz Mader 3775, Curitiba 81350-010, Brazil
- Corresponding authors: fax: +598 2 525 86 17 E-mail: (B. Garat); or fax: +55 41 33163267 E-mail: (B. Dallagiovanna)
| | - Beatriz Garat
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
- Corresponding authors: fax: +598 2 525 86 17 E-mail: (B. Garat); or fax: +55 41 33163267 E-mail: (B. Dallagiovanna)
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25
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Dawson A, Gibellini F, Sienkiewicz N, Tulloch LB, Fyfe PK, McLuskey K, Fairlamb AH, Hunter WN. Structure and reactivity of Trypanosoma brucei pteridine reductase: inhibition by the archetypal antifolate methotrexate. Mol Microbiol 2006; 61:1457-68. [PMID: 16968221 PMCID: PMC1618733 DOI: 10.1111/j.1365-2958.2006.05332.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The protozoan Trypanosoma brucei has a functional pteridine reductase (TbPTR1), an NADPH-dependent short-chain reductase that participates in the salvage of pterins, which are essential for parasite growth. PTR1 displays broad-spectrum activity with pterins and folates, provides a metabolic bypass for inhibition of the trypanosomatid dihydrofolate reductase and therefore compromises the use of antifolates for treatment of trypanosomiasis. Catalytic properties of recombinant TbPTR1 and inhibition by the archetypal antifolate methotrexate have been characterized and the crystal structure of the ternary complex with cofactor NADP+ and the inhibitor determined at 2.2 A resolution. This enzyme shares 50% amino acid sequence identity with Leishmania major PTR1 (LmPTR1) and comparisons show that the architecture of the cofactor binding site, and the catalytic centre are highly conserved, as are most interactions with the inhibitor. However, specific amino acid differences, in particular the placement of Trp221 at the side of the active site, and adjustment of the beta6-alpha6 loop and alpha6 helix at one side of the substrate-binding cleft significantly reduce the size of the substrate binding site of TbPTR1 and alter the chemical properties compared with LmPTR1. A reactive Cys168, within the active site cleft, in conjunction with the C-terminus carboxyl group and His267 of a partner subunit forms a triad similar to the catalytic component of cysteine proteases. TbPTR1 therefore offers novel structural features to exploit in the search for inhibitors of therapeutic value against African trypanosomiasis.
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Affiliation(s)
| | | | | | | | | | | | | | - William N Hunter
- *For correspondence. E-mail ; Tel. (+44) 1382 385745; Fax (+44) 1382 345764
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26
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Schormann N, Pal B, Senkovich O, Carson M, Howard A, Smith C, Delucas L, Chattopadhyay D. Crystal structure of Trypanosoma cruzi pteridine reductase 2 in complex with a substrate and an inhibitor. J Struct Biol 2005; 152:64-75. [PMID: 16168672 DOI: 10.1016/j.jsb.2005.07.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 06/22/2005] [Accepted: 07/07/2005] [Indexed: 11/19/2022]
Abstract
Reduced pteridines are required for a number of important cellular functions. Trypanosomatid parasites, unlike their mammalian hosts, are pteridine auxotrophs and salvage the precursor pteridines from the host and reduce them to the respective biologically active tetrahydro forms using parasite-encoded enzymes. These enzymes may offer selective drug targets. In Leishmania, pteridine reductase 1 (PTR1), the primary enzyme for reducing pterins, is also responsible for resistance to antifolate drugs. Typically, PTR1 is more active with fully oxidized biopterin and folate than with their reduced counterparts. We have identified an enzyme, TcPTR2 of Trypanosoma cruzi, which though very similar to PTR1 in its primary sequence, can reduce only dihydrobiopterin and dihydrofolate and not oxidized pteridines. The structures of an inhibitor (methotrexate) and a substrate (dihydrofolate) complex of this enzyme demonstrate that the orientation of the substrate and the inhibitor in the active site of TcPTR2 are different from each other. However, the orientation of each ligand is similar to that of the corresponding ligand in Leishmania major PTR1 complexes.
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Affiliation(s)
- Norbert Schormann
- Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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27
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Senkovich O, Bhatia V, Garg N, Chattopadhyay D. Lipophilic antifolate trimetrexate is a potent inhibitor of Trypanosoma cruzi: prospect for chemotherapy of Chagas' disease. Antimicrob Agents Chemother 2005; 49:3234-8. [PMID: 16048931 PMCID: PMC1196212 DOI: 10.1128/aac.49.8.3234-3238.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Trypanosoma cruzi, a protozoan parasite, is the causative agent for Chagas' disease, which poses serious public health problem in Latin America. The two drugs available for the treatment of this disease are effective only against recent infections and are toxic. Dihydrofolate reductase (DHFR) has a proven track record as a drug target. The lipophilic antifolate trimetrexate (TMQ), which is an FDA-approved drug for the treatment of Pneumocystis carinii infection in AIDS patients, is a potent inhibitor of T. cruzi DHFR activity, with an inhibitory constant of 6.6 nM. The compound is also highly effective in killing T. cruzi parasites. The 50 and 90% lethal dose values against the trypomastigote are 19 and 36 nM, and the corresponding values for the amastigote form are 26 and 72 nM, respectively. However, as TMQ is also a good inhibitor of human DHFR, further improvement of the selectivity of this drug would be preferable. Identification of a novel antifolate selective against T. cruzi would open up new therapeutic avenues for treatment of Chagas' disease.
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Affiliation(s)
- Olga Senkovich
- University of Alabama at Birmingham, CBSE-250, 1025 18th Street South, Birmingham, AL 35294, USA
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28
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Abstract
As in centuries past, the main weapon against human malaria infections continues to be intervention with drugs, despite the widespread and increasing frequency of parasite populations that are resistant to one or more of the available compounds. This is a particular problem with the lethal species of parasite, Plasmodium falciparum, which claims some two million lives per year as well as causing enormous social and economic problems. Amongst the antimalarial drugs currently in clinical use, the antifolates have the best defined molecular targets, namely the enzymes dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS), which function in the folate metabolic pathway. The products of this pathway, reduced folate cofactors, are essential for DNA synthesis and the metabolism of certain amino acids. Moreover, their formation and interconversions involve a number of other enzymes that have not as yet been exploited as drug targets. Antifolates are of major importance as they currently represent the only inexpensive regime for combating chloroquine-resistant malaria, and are now first-line drugs in a number of African countries. Aspects of our understanding of this pathway and antifolate drug resistance are reviewed here, with a particular emphasis on approaches to analysing the details of, and balance between, folate biosynthesis by the parasite and salvage of pre-formed folate from exogenous sources.
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Affiliation(s)
- John E Hyde
- Faculty of life Sciences, University of Manchester, P.O. Box 88, Manchester M60 1QD, UK.
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29
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Kumar P, Kothari H, Singh N. Overexpression in Escherichia coli and purification of pteridine reductase (PTR1) from a clinical isolate of Leishmania donovani. Protein Expr Purif 2005; 38:228-36. [PMID: 15555938 DOI: 10.1016/j.pep.2004.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Revised: 08/03/2004] [Indexed: 10/26/2022]
Abstract
Pteridine reductase 1 (PTR1) is part of a novel metabolic pathway in Leishmania associated with folate metabolism. Its main function is to salvage pterins but a second one is to reduce folates. The novelty and possible uniqueness of the pathway in which PTR1 is involved opens the possibility of developing specific inhibitors, which in combination with dihydrofolate reductase inhibitors could be highly effective against Leishmania. In order to increase our understanding of this putative important chemotherapeutic target, we present here the cloning, overexpression and purification of this enzyme from a clinical isolate of Leishmania donovani causing kala azar in India. This recombinant enzyme will set the basis for inhibition studies as well as for structure-function relationships.
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Affiliation(s)
- Pranav Kumar
- Drug Target Discovery and Development Division, Central Drug Research Institute, Lucknow, India
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30
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Hardy LW, Peet NP. The multiple orthogonal tools approach to define molecular causation in the validation of druggable targets. Drug Discov Today 2004; 9:117-26. [PMID: 14960389 DOI: 10.1016/s1359-6446(03)02969-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Many genetic (gene deletion, interruption or mutation), epigenetic (such as antisense or small interfering RNA) and immunological methods are being applied in 'high-throughput target validation' studies of the novel potential targets arising from whole genome sequencing. Such applications often focus on 'loss of function' approaches. However, target validation is most reliable when multiple orthogonal approaches are used. Initiating a target-based discovery project based on correlative evidence is faster than awaiting causative evidence. Indeed, the multiple tools needed to generate firm proof usually include methods and reagents only generated after starting a discovery project with little evidence beyond correlations. Robust and rigorous tests of whether a drug candidate is efficacious in vivo because of its effects on a specific molecular particular target are best made by simultaneously applying multiple orthogonal tools. Examples of the orthogonal tools approach will be discussed.
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Affiliation(s)
- Larry W Hardy
- Aurigene Discovery Technologies, Lexington, MO 02420, USA.
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31
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Schormann N, Senkovich O, Ananthan S, Chattopadhyay D. Docking and biological activity of pteridine analogs: search for inhibitors of pteridine reductase enzymes from Trypanosoma cruzi. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0166-1280(03)00403-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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32
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Anacleto C, Abdo MCB, Ferreira AVB, Murta SMF, Romanha AJ, Fernandes AP, Moreira ESA. Structural and functional analysis of an amplification containing a PGPA gene in a glucantime-resistant Leishmania (Viannia) guyanensis cell line. Parasitol Res 2003; 90:110-8. [PMID: 12756544 DOI: 10.1007/s00436-002-0798-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2002] [Accepted: 10/29/2002] [Indexed: 10/25/2022]
Abstract
Drug resistance is a complex phenomenon in Leishmania and commonly involves gene amplification. Active efflux and metal sequestration through a P-glycoprotein have been pointed to as the major mechanisms used by drug-resistant Leishmania. A gene amplification from a glucantime-resistant Leishmania (Viannia) guyanensis cell line was characterised in an attempt to understand the mechanism of metal resistance in this pathogenic species. We show that the amplification is present as an extrachromosomal amplicon of 30 kb and contains a PGPA gene ( LgPGPA), which is overexpressed in the resistant line as shown by Northern and Western blot analyses. In addition, we gathered evidence from transfection experiments for the role of the LgPGPA gene in oxyanion resistance in L. (V.) guyanensis. Our work indicates that, in this pathogenic New World Leishmania species, amplification of the PGPA gene is the major determinant in oxyanion resistance.
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Affiliation(s)
- Charles Anacleto
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, CP 486, CEP 31270-901, Belo Horizonte, MG, Brazil
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33
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Senkovich O, Pal B, Schormann N, Chattopadhyay D. Trypanosoma cruzi genome encodes a pteridine reductase 2 protein. Mol Biochem Parasitol 2003; 127:89-92. [PMID: 12615341 DOI: 10.1016/s0166-6851(02)00309-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Olga Senkovich
- Center for Biophysical Sciences and Engineering & Division of Geographic Medicine, University of Alabama, CBSE-250, 1025 18th Street South, Birmingham, AL 35294, USA
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34
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Gilbert IH. Inhibitors of dihydrofolate reductase in Leishmania and trypanosomes. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1587:249-57. [PMID: 12084467 DOI: 10.1016/s0925-4439(02)00088-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The protozoan diseases leishmaniasis, Chagas' disease and African trypanosomiasis are major health problems in many countries, particularly developing countries, and there are few drugs available to treat these diseases. Dihydrofolate reductase (DHFR) inhibitors have been used successfully in the treatment of a number of other diseases such as cancer, malaria and bacterial infections; however they have not been used for the treatment of these diseases. This article summarises studies on leishmanial and trypanosomal DHFR inhibitor development and evaluation. Possible mechanisms of resistance to DHFR inhibitors are also discussed.
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Affiliation(s)
- Ian H Gilbert
- Welsh School of Pharmacy, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff, UK.
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35
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Ouellette M, Drummelsmith J, El-Fadili A, Kündig C, Richard D, Roy G. Pterin transport and metabolism in Leishmania and related trypanosomatid parasites. Int J Parasitol 2002; 32:385-98. [PMID: 11849635 DOI: 10.1016/s0020-7519(01)00346-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The folate metabolic pathway has been exploited successfully for the development of antimicrobial and antineoplasic agents. Inhibitors of this pathway, however, are not useful against Leishmania and other trypanosomatids. Work on the mechanism of methotrexate resistance in Leishmania has dramatically increased our understanding of folate and pterin metabolism in this organism. The metabolic and cellular functions of the reduced form of folates and pterins are beginning to be established and this work has led to several unexpected findings. Moreover, the currently ongoing sequencing efforts on trypanosomatid genomes are suggesting the presence of several gene products that are likely to require folates and pterins. A number of the properties of folate and pterin metabolism are unique suggesting that these pathways are valid and worthwhile targets for drug development.
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Affiliation(s)
- Marc Ouellette
- Centre de recherche en Infectiologie du CHUL, 2705, boul. Laurier, QC, Sainte-Foy, Canada GIV 4G2.
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36
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Abstract
Drug resistance is complicating the treatment of parasitic diseases. We review here the basic mechanisms of parasite resistance in malaria, sleeping sickness, leishmaniasis and common helminthiases. Parasites resort to multiple biochemical means to achieve resistance and we have begun to isolate and characterize the genes/proteins implicated in resistance. Understanding drug resistance is essential for the control of parasitic diseases.
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Affiliation(s)
- M Ouellette
- Centre de Recherche en Infectiologie du Centre de Recherche du CHUL and Département de Microbiologie, Faculté de Médecine, Université Laval, Québec, Canada.
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37
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Duhagon MA, Dallagiovanna B, Garat B. Unusual features of poly[dT-dG].[dC-dA] stretches in CDS-flanking regions of Trypanosoma cruzi genome. Biochem Biophys Res Commun 2001; 287:98-103. [PMID: 11549259 DOI: 10.1006/bbrc.2001.5545] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In trypanosomatids, the mechanisms of gene expression regulation are not yet well understood. The genes are organized into long polycistronic transcription units separated by intergenic regions that may contain the signaling information for nucleic acid processing. Poly-dinucleotides are frequent in these regions and have been proposed to be involved in gene expression regulation. We analyzed their frequency in CDS-flanking sequences of sense strands in Trypanosoma cruzi and established that all but poly[dC-dC], poly[dC-dG], and poly[dG-dG] are significantly more frequent than expected by chance. Poly[dT-dG].[dC-dA] is among the longest and most frequent poly-dinucleotides and shows a remarkable strand asymmetry. Furthermore, electrophoretic mobility shift assays using T. cruzi epimastigotes nuclear extracts demonstrated the existence of at least, one sequence specific single-strand binding activity for each strand. These results strongly suggest that poly[dT-dG].[dC-dA] sequence is involved in regulatory mechanisms of relevance for the parasite biology.
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Affiliation(s)
- M A Duhagon
- Sección Bioquímica, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
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38
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Cunningham ML, Beverley SM. Pteridine salvage throughout the Leishmania infectious cycle: implications for antifolate chemotherapy. Mol Biochem Parasitol 2001; 113:199-213. [PMID: 11295174 DOI: 10.1016/s0166-6851(01)00213-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protozoan parasites of the trypanosomatid genus Leishmania are pteridine auxotrophs, and have evolved an elaborate and versatile pteridine salvage network capable of accumulating and reducing pteridines. This includes biopterin and folate transporters (BT1 and FT1), pteridine reductase (PTR1), and dihydrofolate reductase-thymidylate synthase (DHFR-TS). Notably, PTR1 is a novel alternative pteridine reductase whose activity is resistant to inhibition by standard antifolates. In cultured promastigote parasites, PTR1 can function as a metabolic by-pass under conditions of DHFR inhibition and thus reduce the efficacy of chemotherapy. To test whether pteridine salvage occurred in the infectious stage of the parasite, we examined several pathogenic species of Leishmania and the disease-causing amastigote stage that resides within human macrophages. To accomplish this we developed a new sensitive HPLC-based assay for PTR1 activity. These studies established the existence of the pteridine salvage pathway throughout the infectious cycle of Leishmania, including amastigotes. In general, activities were not well correlated with RNA transcript levels, suggesting the occurrence of at least two different modes of post-transcriptional regulation. Thus, pteridine salvage by amastigotes may account for the clinical inefficacy of antifolates against leishmaniasis, and ultimately provide insights into how this may be overcome in the future.
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Affiliation(s)
- M L Cunningham
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
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39
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Robello C, Gamarro F, Castanys S, Alvarez-Valin F. Evolutionary relationships in Trypanosoma cruzi: molecular phylogenetics supports the existence of a new major lineage of strains. Gene 2000; 246:331-8. [PMID: 10767555 DOI: 10.1016/s0378-1119(00)00074-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
For the purpose of investigating the evolutionary relationships among strains of the human parasite Trypanosoma cruzi, we have determined the nucleotide sequence, in 16 T. cruzi stocks, of a DNA fragment having approximately 1030 nucleotides in length. Phylogenetic analyses show the presence of at least three major groups of T. cruzi strains, a result that contradicts previous phylogenetic inferences based on polymorphism data. We also performed an analysis of the relative extent of nucleotide divergence among T. cruzi strains compared to the divergence between Leishmania species, using the gene encoding pteridine reductase. The results presented in this work show that the divergence among the most distant T. cruzi strains is at least as high as the divergence between two different species complexes of Leishmania, those containing L. major and L. mexicana.
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Affiliation(s)
- C Robello
- Depto. de Bioquímica, Fac. de Medicina, Montevideo, Uruguay
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40
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Robello C, Dallagiovanna B, Castanys S, Gamarro F, Ehrlich R. Trypanosoma cruzi: molecular cloning of a gene coding for a putative vacuolar protein. Exp Parasitol 2000; 94:129-31. [PMID: 10673350 DOI: 10.1006/expr.1999.4485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We describe the characterization of Tc38, a Trypanosoma cruzi gene coding for a 337-amino-acid protein with a predicted molecular mass of 38 kDa. Tc38 presents similarities to the plant storage vacuolar protein gamma-3-hordein involved in the transport and targeting of prolamins to the vacuole of developing barley endosperm. Western blot analysis using a polyclonal antiserum against recombinant Tc38 revealed that the protein is differentially expressed in the different life stages of the parasite, showing a higher expression in the epimastigote and tripomastigote stages. Immunofluorescence studies suggest that the protein is located in putative vacuolar structures in epimastigotes. The functionality of this protein in T. cruzi remains to be elucidated.
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Affiliation(s)
- C Robello
- Departmento de Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo-Uruguay
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41
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Chowdhury SF, Villamor VB, Guerrero RH, Leal I, Brun R, Croft SL, Goodman JM, Maes L, Ruiz-Perez LM, Pacanowska DG, Gilbert IH. Design, synthesis, and evaluation of inhibitors of trypanosomal and leishmanial dihydrofolate reductase. J Med Chem 1999; 42:4300-12. [PMID: 10543874 DOI: 10.1021/jm981130+] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper concerns the design, synthesis, and evaluation of inhibitors of leishmanial and trypanosomal dihydrofolate reductase. Initially study was made of the structures of the leishmanial and human enzyme active sites to see if there were significant differences which could be exploited for selective drug design. Then a series of compounds were synthesized based on 5-benzyl-2, 4-diaminopyrimidines. These compounds were assayed against the protozoan and human enzymes and showed selectivity for the protozoan enzymes. The structural data was then used to rationalize the enzyme assay data. Compounds were also tested against the clinically relevant forms of the intact parasite. Activity was seen against the trypanosomes for a number of compounds. The compounds were in general less active against Leishmania. This latter result may be due to uptake problems. Two of the compounds also showed some in vivo activity in a model of African trypanosomiasis.
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Affiliation(s)
- S F Chowdhury
- Welsh School of Pharmacy, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3XF, UK
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42
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Kündig C, Leblanc E, Papadopoulou B, Ouellette M. Role of the locus and of the resistance gene on gene amplification frequency in methotrexate resistant Leishmania tarentolae. Nucleic Acids Res 1999; 27:3653-9. [PMID: 10471733 PMCID: PMC148619 DOI: 10.1093/nar/27.18.3653] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The protozoan parasite Leishmania resists the antifolate methotrexate (MTX) by amplifying the R locus dihydrofolate reductase-thymidylate synthase ( dhfr-ts ) gene, the H locus ptr1 pterin reductase gene, and finally by mutation in a common folate/MTX transporter. Amplification of dhfr-ts has never been observed in Leishmania tarentolae MTX resistant mutants while ptr1 amplification is common. We have selected a L.tarentolae ptr1 null mutant for MTX resistance and observed dhfr-ts amplification in this mutant demonstrating that once a preferred resistance mechanism is unavailable, a second one will take over. By introducing the ptr1 gene at the R locus and the dhfr-ts gene at the H locus by gene targeting, we investigated the role of the resistance gene and the locus on the rate of gene amplification. Transfection studies indicated that ptr1 gave higher levels of MTX resistance than dhfr-ts. Consistent with this, when ptr1 was present as part of either the H locus or the R locus it was invariably amplified, while dhfr-ts was only amplified when ptr1 was inactivated. When dhfr-ts was present in a ptr1 null background on both the H locus and the R locus, amplification from the H locus was more frequent suggesting that both the gene and the locus are determining the frequency of gene amplification in Leishmania.
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Affiliation(s)
- C Kündig
- Centre de Recherche en Infectiologie du CHUL and Département de Biologie Médicale, Division de Microbiologie, Faculté de Médecine, Université Laval, Québec, Canada
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43
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Chang CF, Bray T, Whiteley JM. Mutant PTR1 proteins from Leishmania tarentolae: comparative kinetic properties and active-site labeling. Arch Biochem Biophys 1999; 368:161-71. [PMID: 10415124 DOI: 10.1006/abbi.1999.1290] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PTR1, the gene promoting MTX resistance following gene amplification or DNA transfection in Leishmania tarentolae and selected mutants, has been cloned and heavily overexpressed (>100 mg/liter) in Escherichia coli strain BL21 (DE3). Protein has been purified, essentially to homogeneity, in two steps, via ammonium sulfate precipitation and chromatography on DEAE-Trisacryl. The active proteins are tetramers and display optimal pteridine reductase activity at pH 6.0 using biopterin as substrate and NADPH as the reduced dinucleotide cofactor. 2,4-Diaminopteridine substrate analogues are strong competitive inhibitors (K(i) approximately 38 --> 3 nM) against the pterin substrate and both NADP(+) and folate are inhibitors although somewhat weaker. Dihydropteridines are poor substrates compared to the fully oxidized pteridine. Kinetic analysis affords the usual Michaelis constants and in addition shows that inhibition by NADP(+) allows the formation of ternary nonproductive complexes with folate. The kinetic results are consistent with a sequential ordered bi-bi kinetic mechanism in which first NADPH and then pteridine bind to the free enzyme. Sequence comparisons suggest that PTR1 belongs to the short-chain dehydrogenase/reductase (SDR) family containing an amino-terminal glycine-rich dinucleotide binding site plus a catalytic Y(Xaa)(3)K motif. In accord with this observation, the mutants K16A, Y37D, and R39A and the double mutants K17A:R39A and Y37D:R39A all show a two- to threefold lower binding affinity for NADPH and exhibit low or zero activity. Two Y(Xaa)(3)K regions are present in wild-type PTR1 at 152 and 194. Only Y194F gives protein with zero activity. This observation coupled with affinity labeling of PTR1 by oNADP(+) (2', 3'-dialdehyde derivative of NADP(+)) followed by NaBH(4) reduction, V8 protease digestion, and mass spectral analysis suggests that the motif participating in catalysis is that at 194. The mutation K198Q eliminates inactivation by oNADP(+) supporting the hypothesis that K198 is associated with nucleotide orientation, as has been demonstrated for similar lysine residues in other members of the SDR family.
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Affiliation(s)
- C F Chang
- The Scripps Research Institute, La Jolla, California, 92037, USA
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44
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McKerrow JH, Engel JC, Caffrey CR. Cysteine protease inhibitors as chemotherapy for parasitic infections. Bioorg Med Chem 1999; 7:639-44. [PMID: 10353643 DOI: 10.1016/s0968-0896(99)00008-5] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Analysis of the evolution, localization and biologic function of papain family cysteine proteases in metazoan and protozoan parasites has provided important and often surprising insights into the biochemistry and cellular function of this diverse enzyme family. Furthermore, the relative lack of redundancy of cysteine proteases in parasites compared to their mammalian hosts makes them attractive targets for the development of new antiparasitic chemotherapy. The treatment of experimental models of parasitic diseases with cysteine protease inhibitors has provided an important 'proof of concept' for the use of cysteine protease inhibitors in vivo. Evidence has now accumulated that cysteine protease inhibitors can selectively arrest replication of a microbial pathogen without untoward toxicity to the host. Furthermore, this can be achieved with reasonable dosing schedules and oral administration of the drug. Initial studies have confirmed the efficacy of cysteine protease inhibitors in treatment of Trypanosoma cruzi, Plasmodium falciparum and Leishmania major. Work on Trypanosoma brucei, the agent of African trypanosomiasis, is preliminary but also promising. Target validation studies have shown that biotinylated or radiolabeled irreversible inhibitors specifically bind to the cysteine protease targets thought to represent the major activity within the parasite. In the case of T. cruzi, the effect of inhibitors appears to be predominantly in blocking protease processing. Transfection studies using variant constructs have supported this model. Finally, the generation of null mutants for the multiple protease genes in Leishmania mexicana has provided the first genetic support for the key role of this enzyme family in parasite virulence. Safety studies in rodents and analysis of uptake of inhibitors by parasites and host cells suggest that the selectivity of inhibitors for the parasite targets may reside in the lack of redundancy of parasite proteases, the higher concentration of host proteases in intracellular compartments, and differential uptake of inhibitors by parasites. Attempts to elicit resistance to cysteine protease inhibitors in parasite cultures suggest that mechanisms of induced resistance are independent of resistance to the traditional antiparasitic agents. This suggests that cysteine protease inhibitors may provide an alternative to traditional therapy in drug-resistant organisms.
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Affiliation(s)
- J H McKerrow
- Department of Pathology, VA Medical Center, University of California, San Francisco 94121, USA.
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45
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Robello C, Dallagiovanna B, Engel JC, Gamarro F, Castanys S. A new member of YER057c family in Trypanosoma cruzi is adjacent to an ABC-transporter. Gene X 1998; 220:1-12. [PMID: 9767076 DOI: 10.1016/s0378-1119(98)00439-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tcp17 is a Trypanosoma cruzi gene located contiguous to the ABC-transporter tcpgp2. The protein contains 160 amino acid residues with a predicted molecular mass of 16.5kDa. Western blot analysis using a polyclonal antiserum against recombinant TCP17 revealed that the protein is only expressed in the epimastigote form of the parasite; we did not detect the protein either in the amastigote or trypomastigote forms. A sequence comparison of TCP17 showed a remarkable homology with a conserved family of prokaryotic and eukaryotic proteins called YER057c whose function has not yet been characterized. Here, we propose a new signature of this family considering the N-terminal: [IV]-X(4)-[AV]-[AP]-X-[AP]-X(3)-Y-X(9)-[LIVF]-X(2)-[SA]-G-[QS], and the C-terminal: [AT]-R-X(2)-[IVFY]-X-[VC]-X(2)-L-P-X(4)-[LIVM]-E-[IVM] -[DE] motifs. Immunofluorescence and immunoelectron microscopy studies suggest that the protein has a wide distribution in the cell, with a higher concentration in the external side of the plasma membrane, on the Golgi complex and on cytoplasmic vacuoles. Although the physiological function of TCP17 is unknown, its conservation in evolution suggests biological relevance in the parasite.
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Affiliation(s)
- C Robello
- Departamento de Bioquímica y Farmacología Molecular, Instituto de Parasitología y Biomedicina 'López-Neyra', Consejo Superior de Investigaciones Científicas, c/Ventanilla 11, 18001-, Granada, Spain
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