1
|
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.
Collapse
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.)
| |
Collapse
|
2
|
Yoshino R, Yasuo N, Hagiwara Y, Ishida T, Inaoka DK, Amano Y, Tateishi Y, Ohno K, Namatame I, Niimi T, Orita M, Kita K, Akiyama Y, Sekijima M. Discovery of a Hidden Trypanosoma cruzi Spermidine Synthase Binding Site and Inhibitors through In Silico, In Vitro, and X-ray Crystallography. ACS OMEGA 2023; 8:25850-25860. [PMID: 37521650 PMCID: PMC10373461 DOI: 10.1021/acsomega.3c01314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/28/2023] [Indexed: 08/01/2023]
Abstract
In drug discovery research, the selection of promising binding sites and understanding the binding mode of compounds are crucial fundamental studies. The current understanding of the proteins-ligand binding model extends beyond the simple lock and key model to include the induced-fit model, which alters the conformation to match the shape of the ligand, and the pre-existing equilibrium model, selectively binding structures with high binding affinity from a diverse ensemble of proteins. Although methods for detecting target protein binding sites and virtual screening techniques using docking simulation are well-established, with numerous studies reported, they only consider a very limited number of structures in the diverse ensemble of proteins, as these methods are applied to a single structure. Molecular dynamics (MD) simulation is a method for predicting protein dynamics and can detect potential ensembles of protein binding sites and hidden sites unobservable in a single-point structure. In this study, to demonstrate the utility of virtual screening with protein dynamics, MD simulations were performed on Trypanosoma cruzi spermidine synthase to obtain an ensemble of dominant binding sites with a high probability of existence. The structure of the binding site obtained through MD simulation revealed pockets in addition to the active site that was present in the initial structure. Using the obtained binding site structures, virtual screening of 4.8 million compounds by docking simulation, in vitro assays, and X-ray analysis was conducted, successfully identifying two hit compounds.
Collapse
Affiliation(s)
- Ryunosuke Yoshino
- Transborder
Medical Research Center, University of Tsukuba, Tsukuba 305-8577, Japan
- Education
Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Nobuaki Yasuo
- Tokyo
Tech Academy for Convergence of Materials and Informatics (TAC-MI), Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan
| | - Yohsuke Hagiwara
- Education
Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama 226-8501, Japan
- Medicinal
Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, Miyukigaoka, Tsukuba 305-8585, Japan
| | - Takashi Ishida
- School
of Computing, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Daniel Ken Inaoka
- School of
Tropical Medicine and Global Health, Nagasaki
University, Sakamoto, Nagasaki 852-8523, Japan
- Department
of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yasushi Amano
- Medicinal
Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, Miyukigaoka, Tsukuba 305-8585, Japan
| | - Yukihiro Tateishi
- Medicinal
Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, Miyukigaoka, Tsukuba 305-8585, Japan
| | - Kazuki Ohno
- Education
Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama 226-8501, Japan
- Medicinal
Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, Miyukigaoka, Tsukuba 305-8585, Japan
| | - Ichiji Namatame
- Medicinal
Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, Miyukigaoka, Tsukuba 305-8585, Japan
| | - Tatsuya Niimi
- Medicinal
Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, Miyukigaoka, Tsukuba 305-8585, Japan
| | - Masaya Orita
- Medicinal
Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, Miyukigaoka, Tsukuba 305-8585, Japan
| | - Kiyoshi Kita
- School of
Tropical Medicine and Global Health, Nagasaki
University, Sakamoto, Nagasaki 852-8523, Japan
- Department
of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yutaka Akiyama
- Education
Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama 226-8501, Japan
- School
of Computing, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Masakazu Sekijima
- Education
Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama 226-8501, Japan
- School
of Computing, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| |
Collapse
|
3
|
Discovery of novel Leishmania major trypanothione synthetase inhibitors by high-throughput screening. Biochem Biophys Res Commun 2022; 637:308-313. [DOI: 10.1016/j.bbrc.2022.11.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022]
|
4
|
Ali V, Behera S, Nawaz A, Equbal A, Pandey K. Unique thiol metabolism in trypanosomatids: Redox homeostasis and drug resistance. ADVANCES IN PARASITOLOGY 2022; 117:75-155. [PMID: 35878950 DOI: 10.1016/bs.apar.2022.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Trypanosomatids are mainly responsible for heterogeneous parasitic diseases: Leishmaniasis, Sleeping sickness, and Chagas disease and control of these diseases implicates serious challenges due to the emergence of drug resistance. Redox-active biomolecules are the endogenous substances in organisms, which play important role in the regulation of redox homeostasis. The redox-active substances like glutathione, trypanothione, cysteine, cysteine persulfides, etc., and other inorganic intermediates (hydrogen peroxide, nitric oxide) are very useful as defence mechanism. In the present review, the suitability of trypanothione and other essential thiol molecules of trypanosomatids as drug targets are described in Leishmania and Trypanosoma. We have explored the role of tryparedoxin, tryparedoxin peroxidase, ascorbate peroxidase, superoxide dismutase, and glutaredoxins in the anti-oxidant mechanism and drug resistance. Up-regulation of some proteins in trypanothione metabolism helps the parasites in survival against drug pressure (sodium stibogluconate, Amphotericin B, etc.) and oxidative stress. These molecules accept electrons from the reduced trypanothione and donate their electrons to other proteins, and these proteins reduce toxic molecules, neutralize reactive oxygen, or nitrogen species; and help parasites to cope with oxidative stress. Thus, a better understanding of the role of these molecules in drug resistance and redox homeostasis will help to target metabolic pathway proteins to combat Leishmaniasis and trypanosomiases.
Collapse
Affiliation(s)
- Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India.
| | - Sachidananda Behera
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
| | - Afreen Nawaz
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
| | - Asif Equbal
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India; Department of Botany, Araria College, Purnea University, Purnia, Bihar, India
| | - Krishna Pandey
- Department of Clinical Medicine, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
| |
Collapse
|
5
|
Benítez D, Franco J, Sardi F, Leyva A, Durán R, Choi G, Yang G, Kim T, Kim N, Heo J, Kim K, Lee H, Choi I, Radu C, Shum D, No JH, Comini MA. Drug-like molecules with anti-trypanothione synthetase activity identified by high throughput screening. J Enzyme Inhib Med Chem 2022; 37:912-929. [PMID: 35306933 PMCID: PMC8942522 DOI: 10.1080/14756366.2022.2045590] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Trypanothione synthetase (TryS) catalyses the synthesis of N1,N8-bis(glutathionyl)spermidine (trypanothione), which is the main low molecular mass thiol supporting several redox functions in trypanosomatids. TryS attracts attention as molecular target for drug development against pathogens causing severe and fatal diseases in mammals. A drug discovery campaign aimed to identify and characterise new inhibitors of TryS with promising biological activity was conducted. A large compound library (n = 51,624), most of them bearing drug-like properties, was primarily screened against TryS from Trypanosoma brucei (TbTryS). With a true-hit rate of 0.056%, several of the TbTryS hits (IC50 from 1.2 to 36 µM) also targeted the homologue enzyme from Leishmania infantum and Trypanosoma cruzi (IC50 values from 2.6 to 40 µM). Calmidazolium chloride and Ebselen stand out for their multi-species anti-TryS activity at low µM concentrations (IC50 from 2.6 to 13.8 µM). The moieties carboxy piperidine amide and amide methyl thiazole phenyl were identified as novel TbTryS inhibitor scaffolds. Several of the TryS hits presented one-digit µM EC50 against T. cruzi and L. donovani amastigotes but proved cytotoxic against the human osteosarcoma and macrophage host cells (selectivity index ≤ 3). In contrast, seven hits showed a significantly higher selectivity against T. b. brucei (selectivity index from 11 to 182). Non-invasive redox assays confirmed that Ebselen, a multi-TryS inhibitor, induces an intracellular oxidative milieu in bloodstream T. b. brucei. Kinetic and mass spectrometry analysis revealed that Ebselen is a slow-binding inhibitor that modifies irreversible a highly conserved cysteine residue from the TryS’s synthetase domain. The most potent TbTryS inhibitor (a singleton containing an adamantine moiety) exerted a non-covalent, non-competitive (with any of the substrates) inhibition of the enzyme. These data feed the drug discovery pipeline for trypanosomatids with novel and valuable information on chemical entities with drug potential.
Collapse
Affiliation(s)
- Diego Benítez
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Jaime Franco
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Florencia Sardi
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Alejandro Leyva
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Rosario Durán
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Gahee Choi
- Host-Parasite Research Laboratory, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Gyongseon Yang
- Host-Parasite Research Laboratory, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Taehee Kim
- Assay Development and Screening, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Namyoul Kim
- Assay Development and Screening, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Jinyeong Heo
- Assay Development and Screening, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Kideok Kim
- Automation and Logistics Management, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Honggun Lee
- Automation and Logistics Management, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Inhee Choi
- Medicinal Chemistry, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Constantin Radu
- Automation and Logistics Management, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - David Shum
- Assay Development and Screening, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Joo Hwan No
- Host-Parasite Research Laboratory, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Marcelo A Comini
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| |
Collapse
|
6
|
Haindrich AC, Ernst V, Naguleswaran A, Oliveres QF, Roditi I, Rentsch D. Nutrient availability regulates proline/alanine transporters in Trypanosoma brucei. J Biol Chem 2021; 296:100566. [PMID: 33745971 PMCID: PMC8094907 DOI: 10.1016/j.jbc.2021.100566] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/09/2021] [Accepted: 03/17/2021] [Indexed: 11/23/2022] Open
Abstract
Trypanosoma brucei is a species of unicellular parasite that can cause severe diseases in livestock and humans, including African trypanosomiasis and Chagas disease. Adaptation to diverse environments and changes in nutritional conditions is essential for T. brucei to establish an infection when changing hosts or during invasion of different host tissues. One such adaptation is the ability of T. brucei to rapidly switch its energy metabolism from glucose metabolism in the mammalian blood to proline catabolism in the insect stages and vice versa. However, the mechanisms that support the parasite's response to nutrient availability remain unclear. Using RNAseq and qRT-PCR, we investigated the response of T. brucei to amino acid or glucose starvation and found increased mRNA levels of several amino acid transporters, including all genes of the amino acid transporter AAT7-B subgroup. Functional characterization revealed that AAT7-B members are plasma membrane-localized in T. brucei and when expressed in Saccharomyces cerevisiae supported the uptake of proline, alanine, and cysteine, while other amino acids were poorly recognized. All AAT7-B members showed a preference for proline, which is transported with high or low affinity. RNAi-mediated AAT7-B downregulation resulted in a reduction of intracellular proline concentrations and growth arrest under low proline availability in cultured procyclic form parasites. Taken together, these results suggest a role of AAT7-B transporters in the response of T. brucei to proline starvation and proline catabolism.
Collapse
Affiliation(s)
| | - Viona Ernst
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | | | | | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Bern, Switzerland.
| |
Collapse
|
7
|
Piñeyro MD, Arias D, Parodi-Talice A, Guerrero S, Robello C. Trypanothione Metabolism as Drug Target for Trypanosomatids. Curr Pharm Des 2021; 27:1834-1846. [PMID: 33308115 DOI: 10.2174/1381612826666201211115329] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 10/01/2020] [Accepted: 10/08/2020] [Indexed: 11/22/2022]
Abstract
Chagas Disease, African sleeping sickness, and leishmaniasis are neglected diseases caused by pathogenic trypanosomatid parasites, which have a considerable impact on morbidity and mortality in poor countries. The available drugs used as treatment have high toxicity, limited access, and can cause parasite drug resistance. Long-term treatments, added to their high toxicity, result in patients that give up therapy. Trypanosomatids presents a unique trypanothione based redox system, which is responsible for maintaining the redox balance. Therefore, inhibition of these essential and exclusive parasite's metabolic pathways, absent from the mammalian host, could lead to the development of more efficient and safe drugs. The system contains different redox cascades, where trypanothione and tryparedoxins play together a central role in transferring reduced power to different enzymes, such as 2-Cys peroxiredoxins, non-selenium glutathione peroxidases, ascorbate peroxidases, glutaredoxins and methionine sulfoxide reductases, through NADPH as a source of electrons. There is sufficient evidence that this complex system is essential for parasite survival and infection. In this review, we explore what is known in terms of essentiality, kinetic and structural data, and the development of inhibitors of enzymes from this trypanothione-based redox system. The recent advances and limitations in the development of lead inhibitory compounds targeting these enzymes have been discussed. The combination of molecular biology, bioinformatics, genomics, and structural biology is fundamental since the knowledge of unique features of the trypanothione-dependent system will provide tools for rational drug design in order to develop better treatments for these diseases.
Collapse
Affiliation(s)
| | - Diego Arias
- Instituto de Agrobiotecnologia del Litoral y Facultad de Bioquimica y Ciencias Biologicas, CONICET-UNL, Santa F, Argentina
| | | | - Sergio Guerrero
- Instituto de Agrobiotecnologia del Litoral y Facultad de Bioquimica y Ciencias Biologicas, CONICET-UNL, Santa F, Argentina
| | - Carlos Robello
- Unidad de Biologia Molecular, Instituto Pasteur Montevideo, Montevideo, Uruguay
| |
Collapse
|
8
|
Mesías AC, Sasoni N, Arias DG, Pérez Brandán C, Orban OCF, Kunick C, Robello C, Comini MA, Garg NJ, Zago MP. Trypanothione synthetase confers growth, survival advantage and resistance to anti-protozoal drugs in Trypanosoma cruzi. Free Radic Biol Med 2019; 130:23-34. [PMID: 30359758 PMCID: PMC6331241 DOI: 10.1016/j.freeradbiomed.2018.10.436] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 10/09/2018] [Accepted: 10/20/2018] [Indexed: 01/29/2023]
Abstract
BACKGROUND Chagas cardiomyopathy, caused by Trypanosoma cruzi infection, continues to be a neglected illness, and has a major impact on global health. The parasite undergoes several stages of morphological and biochemical changes during its life cycle, and utilizes an elaborated antioxidant network to overcome the oxidants barrier and establish infection in vector and mammalian hosts. Trypanothione synthetase (TryS) catalyzes the biosynthesis of glutathione-spermidine adduct trypanothione (T(SH)2) that is the principal intracellular thiol-redox metabolite in trypanosomatids. METHODS AND RESULTS We utilized genetic overexpression (TryShi) and pharmacological inhibition approaches to examine the role of TryS in T. cruzi proliferation, tolerance to oxidative stress and resistance to anti-protozoal drugs. Our data showed the expression and activity of TryS was increased in all morphological stages of TryShi (vs. control) parasites. In comparison to controls, the TryShi epimastigotes (insect stage) recorded shorter doubling time, and both epimastigotes and infective trypomastigotes of TryShi exhibited 36-71% higher resistance to H2O2 (50-1000 μM) and heavy metal (1-500 μM) toxicity. Treatment with TryS inhibitors (5-30 μM) abolished the proliferation and survival advantages against H2O2 pressure in a dose-dependent manner in both TryShi and control parasites. Further, epimastigote and trypomastigote forms of TryShi (vs. control) T. cruzi tolerated higher doses of benznidazole and nifurtimox, the drugs currently administered for acute Chagas disease treatment. CONCLUSIONS TryS is essential for proliferation and survival of T. cruzi under normal and oxidant stress conditions, and provides an advantage to the parasite to develop resistance against currently used anti-trypanosomal drugs. TryS indispensability has been chemically validated with inhibitors that may be useful for drug combination therapy against Chagas disease.
Collapse
Affiliation(s)
- Andrea C Mesías
- Instituto de Patología Experimental, Universidad Nacional de Salta - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Salta, Argentina
| | - Natalia Sasoni
- Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral - CONICET, Santa Fe, Argentina
| | - Diego G Arias
- Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral - CONICET, Santa Fe, Argentina
| | - Cecilia Pérez Brandán
- Instituto de Patología Experimental, Universidad Nacional de Salta - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Salta, Argentina
| | - Oliver C F Orban
- Technische Universität Braunschweig, Institut für Medizinische und Pharmazeutische Chemie, Beethovenstraße 55, D-38106 Braunschweig, Germany
| | - Conrad Kunick
- Technische Universität Braunschweig, Institut für Medizinische und Pharmazeutische Chemie, Beethovenstraße 55, D-38106 Braunschweig, Germany
| | - Carlos Robello
- Unidad de Biología Molecular, Institut Pasteur de Montevideo, and Departamento de Bioquímica, Facultad de Medicina, Uruguay
| | - Marcelo A Comini
- Redox Biology of Trypanosomes - Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Nisha J Garg
- Departments of Microbiology and Immunology and Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA.
| | - M Paola Zago
- Instituto de Patología Experimental, Universidad Nacional de Salta - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Salta, Argentina.
| |
Collapse
|
9
|
Manta B, Bonilla M, Fiestas L, Sturlese M, Salinas G, Bellanda M, Comini MA. Polyamine-Based Thiols in Trypanosomatids: Evolution, Protein Structural Adaptations, and Biological Functions. Antioxid Redox Signal 2018; 28:463-486. [PMID: 29048199 DOI: 10.1089/ars.2017.7133] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
SIGNIFICANCE Major pathogenic enterobacteria and protozoan parasites from the phylum Euglenozoa, such as trypanosomatids, are endowed with glutathione (GSH)-spermidine (Sp) derivatives that play important roles in signaling and metal and thiol-redox homeostasis. For some Euglenozoa lineages, the GSH-Sp conjugates represent the main redox cosubstrates around which entire new redox systems have evolved. Several proteins underwent molecular adaptations to synthesize and utilize the new polyamine-based thiols. Recent Advances: The genomes of closely related organisms have recently been sequenced, which allows mining and analysis of gene sequences that belong to these peculiar redox systems. Similarly, the three-dimensional structures of several of these proteins have been solved, which allows for comparison with their counterparts in classical redox systems that rely on GSH/glutaredoxin and thioredoxin. CRITICAL ISSUES The evolutionary and structural aspects related to the emergence and use of GSH-Sp conjugates in Euglenozoa are reviewed focusing on unique structural specializations that proteins developed to use N1,N8-bisglutathionylspermidine (trypanothione) as redox cosubstrate. An updated overview on the biochemical and biological significance of the major enzymatic activities is also provided. FUTURE DIRECTIONS A thiol-redox system strictly dependent on trypanothione is a feature unique to trypanosomatids. The physicochemical properties of the polyamine-GSH conjugates were a major driving force for structural adaptation of proteins that use these thiols as ligand and redox cofactor. In fact, the structural differences of indispensable components of this system can be exploited toward selective drug development. Future research should clarify whether additional cellular processes are regulated by the trypanothione system. Antioxid. Redox Signal. 28, 463-486.
Collapse
Affiliation(s)
- Bruno Manta
- 1 Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo , Montevideo, Uruguay .,2 Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica , Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Mariana Bonilla
- 1 Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo , Montevideo, Uruguay .,2 Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica , Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Lucía Fiestas
- 1 Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo , Montevideo, Uruguay
| | - Mattia Sturlese
- 3 Department of Chemical Sciences, Università degli Studi di Padova , Padova, Italy
| | - Gustavo Salinas
- 4 Worm Biology Lab, Institut Pasteur de Montevideo , Montevideo, Uruguay .,5 Departamento de Biociencias, Facultad de Química, Universidad de la República , Montevideo, Uruguay
| | - Massimo Bellanda
- 3 Department of Chemical Sciences, Università degli Studi di Padova , Padova, Italy
| | - Marcelo A Comini
- 1 Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo , Montevideo, Uruguay
| |
Collapse
|
10
|
Franco J, Scarone L, Comini MA. Drugs and Drug Resistance in African and American Trypanosomiasis. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2018. [DOI: 10.1016/bs.armc.2018.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
11
|
Yoshino R, Yasuo N, Hagiwara Y, Ishida T, Inaoka DK, Amano Y, Tateishi Y, Ohno K, Namatame I, Niimi T, Orita M, Kita K, Akiyama Y, Sekijima M. In silico, in vitro, X-ray crystallography, and integrated strategies for discovering spermidine synthase inhibitors for Chagas disease. Sci Rep 2017; 7:6666. [PMID: 28751689 PMCID: PMC5532286 DOI: 10.1038/s41598-017-06411-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/14/2017] [Indexed: 01/23/2023] Open
Abstract
Chagas disease results from infection by Trypanosoma cruzi and is a neglected tropical disease (NTD). Although some treatment drugs are available, their use is associated with severe problems, including adverse effects and limited effectiveness during the chronic disease phase. To develop a novel anti-Chagas drug, we virtually screened 4.8 million small molecules against spermidine synthase (SpdSyn) as the target protein using our super computer “TSUBAME2.5” and conducted in vitro enzyme assays to determine the half-maximal inhibitory concentration values. We identified four hit compounds that inhibit T. cruzi SpdSyn (TcSpdSyn) by in silico and in vitro screening. We also determined the TcSpdSyn–hit compound complex structure using X-ray crystallography, which shows that the hit compound binds to the putrescine-binding site and interacts with Asp171 through a salt bridge.
Collapse
Affiliation(s)
- Ryunosuke Yoshino
- Advanced Computational Drug Discovery Unit, Institute of Innovative Research, Tokyo Institute of Technology, 4259-J3-23, Nagatsuta-cho, Midori-ku, Yokohama, 226-8501, Japan.,Education Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama, 226-8501, Japan.,Global Scientific Information and Computing Center, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan.,Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.,Department of Computer Science, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8550, Japan
| | - Nobuaki Yasuo
- Education Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama, 226-8501, Japan.,Department of Computer Science, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8550, Japan
| | - Yohsuke Hagiwara
- Education Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama, 226-8501, Japan.,Medicinal Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Takashi Ishida
- Advanced Computational Drug Discovery Unit, Institute of Innovative Research, Tokyo Institute of Technology, 4259-J3-23, Nagatsuta-cho, Midori-ku, Yokohama, 226-8501, Japan.,Education Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama, 226-8501, Japan.,Department of Computer Science, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8550, Japan
| | - Daniel Ken Inaoka
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.,School of Tropical Medicine and Global Health, Nagasaki University, Sakamoto, Nagasaki, 852-8523, Japan
| | - Yasushi Amano
- Medicinal Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Yukihiro Tateishi
- Medicinal Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Kazuki Ohno
- Education Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama, 226-8501, Japan.,Medicinal Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan.,Catalyst Inc., Risona Kudan Building 5F KS Floor, 1-5-6 Kudan Minami, Chiyoda-ku, Tokyo, 102-0074, Japan
| | - Ichiji Namatame
- Medicinal Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Tatsuya Niimi
- Medicinal Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Masaya Orita
- Medicinal Chemistry Research Labs, Drug Discovery Research, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.,School of Tropical Medicine and Global Health, Nagasaki University, Sakamoto, Nagasaki, 852-8523, Japan
| | - Yutaka Akiyama
- Advanced Computational Drug Discovery Unit, Institute of Innovative Research, Tokyo Institute of Technology, 4259-J3-23, Nagatsuta-cho, Midori-ku, Yokohama, 226-8501, Japan.,Education Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama, 226-8501, Japan.,Department of Computer Science, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8550, Japan
| | - Masakazu Sekijima
- Advanced Computational Drug Discovery Unit, Institute of Innovative Research, Tokyo Institute of Technology, 4259-J3-23, Nagatsuta-cho, Midori-ku, Yokohama, 226-8501, Japan. .,Education Academy of Computational Life Sciences (ACLS), Tokyo Institute of Technology, Yokohama, 226-8501, Japan. .,Global Scientific Information and Computing Center, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan. .,Department of Computer Science, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8550, Japan.
| |
Collapse
|
12
|
Adinehbeigi K, Razi Jalali MH, Shahriari A, Bahrami S. In vitro antileishmanial activity of fisetin flavonoid via inhibition of glutathione biosynthesis and arginase activity in Leishmania infantum. Pathog Glob Health 2017; 111:176-185. [PMID: 28385129 PMCID: PMC5498762 DOI: 10.1080/20477724.2017.1312777] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
With the increasing emergence of drug resistant Leishmania sp. in recent years, combination therapy has been considered as a useful way to treat and control of Leishmaniasis. The present study was designed to evaluate the antileishmanial effects of the fisetin alone and combination of fisetin plus Meglumine antimoniate (Fi-MA) against Leishmania infantum. The IC50 values for fisetin were obtained 0.283 and 0.102 μM against promastigotes and amastigote forms, respectively. Meglumine antimoniate (MA, Glucantime) as control drug also revealed IC50 values of 0.247 and 0.105 μM for promastigotes and amastigotes of L. infantum, respectively. In order to determine the mode of action of fisetin and Meglumine antimoniate (MA, Glucantime), the activities of arginase (ARG), catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) were measured. Moreover, intracellular glutathione (GSH) and nitric oxide (NO) levels in L. infantum-infected macrophages and L. infantum promastigotes which were treated with IC50 concentrations of fisetin, MA and Fi-MA were investigated. Our results showed that MA decreased CAT and SOD activity and increased NO levels in L. infantum-infected macrophages. In promastigotes, MA inhibited parasite SOD activity and reduced parasite NO production. The decreased levels of most of the antioxidant enzymes, accompanying by the raised level of NO in treated macrophages with MA, were observed to regain their normal profiles due to Fi-MA treatment. Furthermore, fisetin could prevent the growth of promastigotes by inhibition of ARG activity and reduction of GSH levels and NO production. In conclusion, these findings showed that fisetin improves MA side effects.
Collapse
Affiliation(s)
- Keivan Adinehbeigi
- Faculty of Veterinary Medicine, Pathobiology Department, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | | | - Ali Shahriari
- Faculty of Veterinary Medicine, Pathobiology Department, Shahid Chamran University of Ahvaz, Ahvaz, Iran
- Faculty of Veterinary Medicine, Basic sciences Department, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Somayeh Bahrami
- Faculty of Veterinary Medicine, Pathobiology Department, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| |
Collapse
|
13
|
Singh K, Ali V, Pratap Singh K, Gupta P, Suman SS, Ghosh AK, Bimal S, Pandey K, Das P. Deciphering the interplay between cysteine synthase and thiol cascade proteins in modulating Amphotericin B resistance and survival of Leishmania donovani under oxidative stress. Redox Biol 2017; 12:350-366. [PMID: 28288415 PMCID: PMC5349463 DOI: 10.1016/j.redox.2017.03.004] [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: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 12/13/2022] Open
Abstract
Leishmania donovani is the causative organism of the neglected human disease known as visceral leishmaniasis which is often fatal, if left untreated. The cysteine biosynthesis pathway of Leishmania may serve as a potential drug target because it is different from human host and regulates downstream components of redox metabolism of the parasites; essential for their survival, pathogenicity and drug resistance. However, despite the apparent dependency of redox metabolism of cysteine biosynthesis pathway, the role of L. donovani cysteine synthase (LdCS) in drug resistance and redox homeostasis has been unexplored. Herein, we report that over-expression of LdCS in Amphotericin B (Amp B) sensitive strain (S1-OE) modulates resistance towards oxidative stress and drug pressure. We observed that antioxidant enzyme activities were up-regulated in S1-OE parasites and these parasites alleviate intracellular reactive oxygen species (ROS) efficiently by maintaining the reduced thiol pool. In contrast to S1-OE parasites, Amp B sensitive strain (S1) showed higher levels of ROS which was positively correlated with the protein carbonylation levels and negatively correlated with cell viability. Moreover, further investigations showed that LdCS over-expression also augments the ROS-primed induction of LdCS-GFP as well as endogenous LdCS and thiol pathway proteins (LdTryS, LdTryR and LdcTXN) in L. donovani parasites; which probably aids in stress tolerance and drug resistance. In addition, the expression of LdCS was found to be up-regulated in Amp B resistant isolates and during infective stationary stages of growth and consistent with these observations, our ex vivo infectivity studies confirmed that LdCS over-expression enhances the infectivity of L. donovani parasites. Our results reveal a novel crosstalk between LdCS and thiol metabolic pathway proteins and demonstrate the crucial role of LdCS in drug resistance and redox homeostasis of Leishmania. Over-expression of CS in L. donovani modulates oxidative stress & Amp B resistance. Over-expressing parasite possess higher thiol to counteract the oxidative stress. Over-expressing parasites showed increased activity of TXNPx, GST, SOD, and APx. Expression/activity of LdCS is up-regulated in Amp B resistant clinical isolates. Ex vivo results confirm that LdCS over-expression enhance the parasites infectivity. Over-expressing parasites survived long time under oxidative stress conditions.
Collapse
Affiliation(s)
- Kuljit Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India; Department of Biotechnology, National Institute of Pharmaceutical Education and Research, EPIP Complex, Hajipur 844102, India
| | - Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India; Department of Biotechnology, National Institute of Pharmaceutical Education and Research, EPIP Complex, Hajipur 844102, India.
| | - Krishn Pratap Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Parool Gupta
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Shashi S Suman
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Ayan K Ghosh
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Sanjiva Bimal
- Department of Immunology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Krishna Pandey
- Department of Clinical Medicine, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| | - Pradeep Das
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India
| |
Collapse
|
14
|
5-Substituted 3-chlorokenpaullone derivatives are potent inhibitors of Trypanosoma brucei bloodstream forms. Bioorg Med Chem 2016; 24:3790-800. [DOI: 10.1016/j.bmc.2016.06.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/09/2016] [Accepted: 06/11/2016] [Indexed: 01/31/2023]
|
15
|
Up-regulation of cytosolic tryparedoxin in Amp B resistant isolates of Leishmania donovani and its interaction with cytosolic tryparedoxin peroxidase. Biochimie 2016; 121:312-25. [DOI: 10.1016/j.biochi.2015.12.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/26/2015] [Indexed: 11/18/2022]
|
16
|
Kim DH, Achcar F, Breitling R, Burgess KE, Barrett MP. LC-MS-based absolute metabolite quantification: application to metabolic flux measurement in trypanosomes. Metabolomics 2015; 11:1721-1732. [PMID: 26491423 PMCID: PMC4605981 DOI: 10.1007/s11306-015-0827-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/25/2015] [Indexed: 01/15/2023]
Abstract
Human African trypanosomiasis is a neglected tropical disease caused by the protozoan parasite, Trypanosoma brucei. In the mammalian bloodstream, the trypanosome's metabolism differs significantly from that of its host. For example, the parasite relies exclusively on glycolysis for energy source. Recently, computational and mathematical models of trypanosome metabolism have been generated to assist in understanding the parasite metabolism with the aim of facilitating drug development. Optimisation of these models requires quantitative information, including metabolite concentrations and/or metabolic fluxes that have been hitherto unavailable on a large scale. Here, we have implemented an LC-MS-based method that allows large scale quantification of metabolite levels by using U-13C-labelled E.coli extracts as internal standards. Known amounts of labelled E. coli extract were added into the parasite samples, as well as calibration standards, and used to obtain calibration curves enabling us to convert intensities into concentrations. This method allowed us to reliably quantify the changes of 43 intracellular metabolites and 32 extracellular metabolites in the medium over time. Based on the absolute quantification, we were able to compute consumption and production fluxes. These quantitative data can now be used to optimise computational models of parasite metabolism.
Collapse
Affiliation(s)
- Dong-Hyun Kim
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA UK
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Fiona Achcar
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA UK
| | - Rainer Breitling
- Manchester Centre of Synthetic Biology for Fine and Speciality Chemicals, Manchester Institute of Biotechnology, Faculty of Life Sciences, University of Manchester, Manchester, M1 7DN UK
| | - Karl E. Burgess
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G61 1QH UK
| | - Michael P. Barrett
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA UK
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G61 1QH UK
| |
Collapse
|
17
|
Achcar F, Fadda A, Haanstra JR, Kerkhoven EJ, Kim DH, Leroux AE, Papamarkou T, Rojas F, Bakker BM, Barrett MP, Clayton C, Girolami M, Krauth-Siegel RL, Matthews KR, Breitling R. The silicon trypanosome: a test case of iterative model extension in systems biology. Adv Microb Physiol 2014; 64:115-43. [PMID: 24797926 DOI: 10.1016/b978-0-12-800143-1.00003-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The African trypanosome, Trypanosoma brucei, is a unicellular parasite causing African Trypanosomiasis (sleeping sickness in humans and nagana in animals). Due to some of its unique properties, it has emerged as a popular model organism in systems biology. A predictive quantitative model of glycolysis in the bloodstream form of the parasite has been constructed and updated several times. The Silicon Trypanosome is a project that brings together modellers and experimentalists to improve and extend this core model with new pathways and additional levels of regulation. These new extensions and analyses use computational methods that explicitly take different levels of uncertainty into account. During this project, numerous tools and techniques have been developed for this purpose, which can now be used for a wide range of different studies in systems biology.
Collapse
Affiliation(s)
- Fiona Achcar
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Abeer Fadda
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Jurgen R Haanstra
- Department of Pediatrics, Centre for Liver Digestive and Metabolic Diseases, and Systems Biology Centre for Energy Metabolism and Ageing, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Eduard J Kerkhoven
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, and Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; Systems and Synthetic Biology Group, Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Dong-Hyun Kim
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, and Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | - Theodore Papamarkou
- The Department of Statistical Science and The Centre for Computational Statistics and Machine Learning University College London, London, United Kingdom
| | - Federico Rojas
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Barbara M Bakker
- Department of Pediatrics, Centre for Liver Digestive and Metabolic Diseases, and Systems Biology Centre for Energy Metabolism and Ageing, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Michael P Barrett
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, and Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Mark Girolami
- The Department of Statistical Science and The Centre for Computational Statistics and Machine Learning University College London, London, United Kingdom
| | | | - Keith R Matthews
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Rainer Breitling
- Manchester Institute of Biotechnology, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom.
| |
Collapse
|
18
|
Sousa AF, Gomes-Alves AG, Benítez D, Comini MA, Flohé L, Jaeger T, Passos J, Stuhlmann F, Tomás AM, Castro H. Genetic and chemical analyses reveal that trypanothione synthetase but not glutathionylspermidine synthetase is essential for Leishmania infantum. Free Radic Biol Med 2014; 73:229-38. [PMID: 24853758 DOI: 10.1016/j.freeradbiomed.2014.05.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 11/23/2022]
Abstract
Trypanothione is a unique and essential redox metabolite of trypanosomatid parasites, the biosynthetic pathway of which is regarded as a promising target for antiparasitic drugs. Synthesis of trypanothione occurs by the consecutive conjugation of two glutathione molecules to spermidine. Both reaction steps are catalyzed by trypanothione synthetase (TRYS), a molecule known to be essential in Trypanosoma brucei. However, other trypanosomatids (including some Leishmania species and Trypanosoma cruzi) potentially express one additional enzyme, glutathionylspermidine synthetase (GSPS), capable of driving the first step of trypanothione synthesis yielding glutathionylspermidine. Because this monothiol can substitute for trypanothione in some reactions, the possibility existed that TRYS was redundant in parasites harboring GSPS. To clarify this issue, the functional relevance of both GSPS and TRYS was investigated in Leishmania infantum (Li). Employing a gene-targeting approach, we generated a gsps(-/-) knockout line, which was viable and capable of replicating in both life cycle stages of the parasite, thus demonstrating the superfluous role of LiGSPS. In contrast, elimination of both LiTRYS alleles was not possible unless parasites were previously complemented with an episomal copy of the gene. Retention of extrachromosomal LiTRYS in the trys(-/-)/+TRYS line after several passages in culture further supported the essentiality of this gene for survival of L. infantum (including its clinically relevant stage), hence ruling out the hypothesis of functional complementation by LiGSPS. Chemical targeting of LiTRYS with a drug-like compound was shown to also lead to parasite death. Overall, this study disqualifies GSPS as a target for drug development campaigns and, by genetic and chemical evidence, validates TRYS as a chemotherapeutic target in a parasite endowed with GSPS and, thus, probably along the entire trypanosomatid lineage.
Collapse
Affiliation(s)
- André F Sousa
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal
| | - Ana G Gomes-Alves
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal
| | - Diego Benítez
- Laboratory of Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, CP 11400 Montevideo, Uruguay
| | - Marcelo A Comini
- Laboratory of Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, CP 11400 Montevideo, Uruguay
| | - Leopold Flohé
- Departamento de Bioquímica, Universidad de la República, CP 11800 Montevideo, Uruguay, and Department of Molecular Medicine, Università degli Studi di Padova, 35131 Padova, Italy
| | - Timo Jaeger
- German Center for Infection Research, 38124 Braunschweig, Germany
| | - Joana Passos
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal
| | | | - Ana M Tomás
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4099-003 Porto, Portugal
| | - Helena Castro
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal.
| |
Collapse
|
19
|
Equbal A, Suman SS, Anwar S, Singh KP, Zaidi A, Sardar AH, Das P, Ali V. Stage-dependent expression and up-regulation of trypanothione synthetase in amphotericin B resistant Leishmania donovani. PLoS One 2014; 9:e97600. [PMID: 24901644 PMCID: PMC4046939 DOI: 10.1371/journal.pone.0097600] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 04/22/2014] [Indexed: 11/27/2022] Open
Abstract
Kinetoplastids differ from other organisms in their ability to conjugate glutathione and spermidine to form trypanothione which is involved in maintaining redox homeostasis and removal of toxic metabolites. It is also involved in drug resistance, antioxidant mechanism, and defense against cellular oxidants. Trypanothione synthetase (TryS) of thiol metabolic pathway is the sole enzyme responsible for the biosynthesis of trypanothione in Leishmania donovani. In this study, TryS gene of L. donovani (LdTryS) was cloned, expressed, and fusion protein purified with affinity column chromatography. The purified protein showed optimum enzymatic activity at pH 8.0–8.5. The TryS amino acids sequences alignment showed that all amino acids involved in catalytic and ligands binding of L. major are conserved in L. donovani. Subcellular localization using digitonin fractionation and immunoblot analysis showed that LdTryS is localized in the cytoplasm. Furthermore, RT-PCR coupled with immunoblot analysis showed that LdTryS is overexpressed in Amp B resistant and stationary phase promastigotes (∼2.0-folds) than in sensitive strain and logarithmic phase, respectively, which suggests its involvement in Amp B resistance. Also, H2O2 treatment upto 150 µM for 8 hrs leads to 2-fold increased expression of LdTryS probably to cope up with oxidative stress generated by H2O2. Therefore, this study demonstrates stage- and Amp B sensitivity-dependent expression of LdTryS in L. donovani and involvement of TryS during oxidative stress to help the parasites survival.
Collapse
Affiliation(s)
- Asif Equbal
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Shashi Shekhar Suman
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Shadab Anwar
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Krishn Pratap Singh
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Amir Zaidi
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Abul Hasan Sardar
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Pradeep Das
- Department of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| | - Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, AgamKuan, Patna, India
| |
Collapse
|
20
|
Genetic validation of Trypanosoma brucei glutathione synthetase as an essential enzyme. EUKARYOTIC CELL 2014; 13:614-24. [PMID: 24610661 DOI: 10.1128/ec.00015-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human African trypanosomiasis (HAT) is a debilitating and fatal vector-borne disease. Polyamine biosynthesis is the target of one of the key drugs (eflornithine) used for the treatment of late-stage disease, suggesting that the pathway might be exploited for the identification of additional drug targets. The polyamine spermidine is required in trypanosomatid parasites for formation of a unique redox cofactor termed trypanothione, which is formed from the conjugation of glutathione to spermidine. Here we characterize recombinant Trypanosoma brucei glutathione synthetase (TbGS) and show that depletion of TbGS in blood-form parasites using a regulated knockout strategy leads to loss of trypanothione and to cell death as quantified by fluorescence-activated cell sorter (FACS) analysis. These data suggest that >97% depletion of TbGS is required before trypanothione is depleted and cell growth arrest is observed. Exogenous glutathione was able to partially compensate for the loss of TbGS, suggesting that parasites are able to transport intact glutathione. Finally, reduced expression of TbGS leads to increased levels of upstream glutathione biosynthetic enzymes and decreased expression of polyamine biosynthetic enzymes, providing evidence that the cells cross regulate the two branches of the trypanothione biosynthetic pathway to maintain spermidine and trypanothione homeostasis.
Collapse
|
21
|
Saudagar P, Dubey VK. Molecular mechanisms of in vitro betulin-induced apoptosis of Leishmania donovani. Am J Trop Med Hyg 2014; 90:354-60. [PMID: 24420777 DOI: 10.4269/ajtmh.13-0320] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Although leishmanial infections of humans occur globally, the major health impact lies in developing nations, thus, leishmaniases remain "neglected" diseases for new drugs development. Multidrug resistance has been documented in most countries where leishmaniases is endemic. Betulin is a widely available and affordable natural product exerting leishmanicidal activity at micromolar concentration. In this study, the molecular mechanisms of death that contribute to the anti-leishmanial activity of betulin are investigated. In promastigotes, betulin stimulated reactive oxygen species generation at micromolar concentrations in Leishmania. Apoptosis was observed in betulin-treated promastigotes using flow cytometric analysis of treated cells stained with annexin V-FITC and propidium iodide. Furthermore, betulin treatment of promastigotes led to mitochondrial membrane damage, activation of caspase-like proteases, and DNA fragmentation in Leishmania donovani promastigotes. Betulin treatment of amastigotes cultured within macrophages, resulted in a reduced number of amastigotes, with no substantive cytotoxic damage to the host macrophage cells at leishmanicidal drug concentrations.
Collapse
Affiliation(s)
- Prakash Saudagar
- Department of Biotechnology, Indian Institute of Technology Guwahati, Assam, India
| | | |
Collapse
|
22
|
Trypanothione: A unique bis-glutathionyl derivative in trypanosomatids. Biochim Biophys Acta Gen Subj 2013; 1830:3199-216. [DOI: 10.1016/j.bbagen.2013.01.013] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/11/2013] [Accepted: 01/16/2013] [Indexed: 11/21/2022]
|
23
|
Gu X, Reid D, Higham DJ, Gilbert D. Mathematical modelling of polyamine metabolism in bloodstream-form Trypanosoma brucei: an application to drug target identification. PLoS One 2013; 8:e53734. [PMID: 23372667 PMCID: PMC3553166 DOI: 10.1371/journal.pone.0053734] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 12/04/2012] [Indexed: 11/23/2022] Open
Abstract
We present the first computational kinetic model of polyamine metabolism in bloodstream-form Trypanosoma brucei, the causative agent of human African trypanosomiasis. We systematically extracted the polyamine pathway from the complete metabolic network while still maintaining the predictive capability of the pathway. The kinetic model is constructed on the basis of information gleaned from the experimental biology literature and defined as a set of ordinary differential equations. We applied Michaelis-Menten kinetics featuring regulatory factors to describe enzymatic activities that are well defined. Uncharacterised enzyme kinetics were approximated and justified with available physiological properties of the system. Optimisation-based dynamic simulations were performed to train the model with experimental data and inconsistent predictions prompted an iterative procedure of model refinement. Good agreement between simulation results and measured data reported in various experimental conditions shows that the model has good applicability in spite of there being gaps in the required data. With this kinetic model, the relative importance of the individual pathway enzymes was assessed. We observed that, at low-to-moderate levels of inhibition, enzymes catalysing reactions of de novo AdoMet (MAT) and ornithine production (OrnPt) have more efficient inhibitory effect on total trypanothione content in comparison to other enzymes in the pathway. In our model, prozyme and TSHSyn (the production catalyst of total trypanothione) were also found to exhibit potent control on total trypanothione content but only when they were strongly inhibited. Different chemotherapeutic strategies against T. brucei were investigated using this model and interruption of polyamine synthesis via joint inhibition of MAT or OrnPt together with other polyamine enzymes was identified as an optimal therapeutic strategy.
Collapse
Affiliation(s)
- Xu Gu
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom.
| | | | | | | |
Collapse
|
24
|
Mashiyama ST, Koupparis K, Caffrey CR, McKerrow JH, Babbitt PC. A global comparison of the human and T. brucei degradomes gives insights about possible parasite drug targets. PLoS Negl Trop Dis 2012; 6:e1942. [PMID: 23236535 PMCID: PMC3516576 DOI: 10.1371/journal.pntd.0001942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 10/23/2012] [Indexed: 01/26/2023] Open
Abstract
We performed a genome-level computational study of sequence and structure similarity, the latter using crystal structures and models, of the proteases of Homo sapiens and the human parasite Trypanosoma brucei. Using sequence and structure similarity networks to summarize the results, we constructed global views that show visually the relative abundance and variety of proteases in the degradome landscapes of these two species, and provide insights into evolutionary relationships between proteases. The results also indicate how broadly these sequence sets are covered by three-dimensional structures. These views facilitate cross-species comparisons and offer clues for drug design from knowledge about the sequences and structures of potential drug targets and their homologs. Two protease groups (“M32” and “C51”) that are very different in sequence from human proteases are examined in structural detail, illustrating the application of this global approach in mining new pathogen genomes for potential drug targets. Based on our analyses, a human ACE2 inhibitor was selected for experimental testing on one of these parasite proteases, TbM32, and was shown to inhibit it. These sequence and structure data, along with interactive versions of the protein similarity networks generated in this study, are available at http://babbittlab.ucsf.edu/resources.html. Human African trypanosomiasis (HAT) is caused by the protozoan parasite Trypanosoma brucei. HAT is fatal unless treated, yet the current treatment itself can cause death. New treatments are urgently needed. Our study focuses on proteases, which are enzymes that break down proteins. Because of their roles in many centrally important biological processes, proteases are targets for drugs to treat a variety of diseases including parasite infection. The recent explosion of protein sequence and structure information in public databases has made surveys of proteins on a genomic scale possible. However, collecting specific data of interest from diverse databases and synthesizing them in a way that is easy to interpret can be difficult. We used T. brucei and human protease sequences, crystal structures, and models to create network views that show how proteases cluster by similarity. Such views are valuable not only for understanding the evolution of the protein repertoire in each species, but also can give important clues for drug design. Two T. brucei protease groups (“M32” and “C51”) that are very different in sequence from human proteases were examined in structural detail. Based on our analyses, a human ACE2 inhibitor was selected for experimental testing on one of these parasite proteases, TbM32, and was shown to inhibit it.
Collapse
Affiliation(s)
- Susan T. Mashiyama
- Department of Bioengineering and Therapeutic Sciences, California Institute for Quantitative Biomedical Research (QB3), University of California San Francisco, San Francisco, California, United States of America
- Center for Discovery and Innovation in Parasitic Diseases, and Department of Pathology, QB3, University of California San Francisco, San Francisco, California, United States of America
| | - Kyriacos Koupparis
- Center for Discovery and Innovation in Parasitic Diseases, and Department of Pathology, QB3, University of California San Francisco, San Francisco, California, United States of America
| | - Conor R. Caffrey
- Center for Discovery and Innovation in Parasitic Diseases, and Department of Pathology, QB3, University of California San Francisco, San Francisco, California, United States of America
| | - James H. McKerrow
- Center for Discovery and Innovation in Parasitic Diseases, and Department of Pathology, QB3, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (JHM); (PCB)
| | - Patricia C. Babbitt
- Department of Bioengineering and Therapeutic Sciences, California Institute for Quantitative Biomedical Research (QB3), University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (JHM); (PCB)
| |
Collapse
|
25
|
Fiorillo A, Colotti G, Boffi A, Baiocco P, Ilari A. The crystal structures of the tryparedoxin-tryparedoxin peroxidase couple unveil the structural determinants of Leishmania detoxification pathway. PLoS Negl Trop Dis 2012; 6:e1781. [PMID: 22928053 PMCID: PMC3424247 DOI: 10.1371/journal.pntd.0001781] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 07/03/2012] [Indexed: 12/20/2022] Open
Abstract
Leishmaniasis is a neglected disease caused by Leishmania, an intracellular protozoan parasite which possesses a unique thiol metabolism based on trypanothione. Trypanothione is used as a source of electrons by the tryparedoxin/tryparedoxin peroxidase system (TXN/TXNPx) to reduce the hydroperoxides produced by macrophages during infection. This detoxification pathway is not only unique to the parasite but is also essential for its survival; therefore, it constitutes a most attractive drug target. Several forms of TXNPx, with very high sequence identity to one another, have been found in Leishmania strains, one of which has been used as a component of a potential anti-leishmanial polyprotein vaccine. The structures of cytosolic TXN and TXNPx from L. major (LmTXN and LmTXNPx) offer a unique opportunity to study peroxide reduction in Leishmania parasites at a molecular level, and may provide new tools for multienzyme inhibition-based drug discovery. Structural analyses bring out key structural features to elucidate LmTXN and LmTXNPx function. LmTXN displays an unusual N-terminal α-helix which allows the formation of a stable domain-swapped dimer. In LmTXNPx, crystallized in reducing condition, both the locally unfolded (LU) and fully folded (FF) conformations, typical of the oxidized and reduced protein respectively, are populated. The structural analysis presented here points to a high flexibility of the loop that includes the peroxidatic cysteine which facilitates Cys52 to form an inter-chain disulfide bond with the resolving cysteine (Cys173), thereby preventing over-oxidation which would inactivate the enzyme. Analysis of the electrostatic surface potentials of both LmTXN and LmTXNPx unveils the structural elements at the basis of functionally relevant interaction between the two proteins. Finally, the structural analysis of TXNPx allows us to identify the position of the epitopes that make the protein antigenic and therefore potentially suitable to be used in an anti-leishmanial polyprotein vaccine. Leishmania spp. are protozoa responsible for Leishmaniases, neglected diseases killing up to 60,000 people every year. Current therapies rely mainly on antimonial drugs that are inadequate due to poor drug efficacy and safety, combined with increasing drug resistance. To overcome these problems, there is an urgent need to find new and more affordable drugs. Leishmania reduces the hydrogen peroxide produced by macrophages during the infection by means of the tryparedoxin/tryparedoxin peroxidase couple. The two enzymes are potentially suitable drug targets since they are both necessary for parasite survival and absent in the human host. To understand the molecular basis of peroxide reduction in the Leishmania parasites, we have solved the X-ray crystal structures of both enzymes. Structural analyses highlight oligomerization of the two proteins and allow the regions responsible for their interaction to be identified. Moreover, based on the X-ray structures and on electronic microscopy data present in literature for the homologous proteins from Trypanosoma brucei, we have generated a model of interaction between tryparedoxin and tryparedoxin peroxidase from L. major. From the X-ray structure and from this model, we have identified the epitopes of tryparedoxin peroxidase, which is part of a potential threecomponent vaccine that is presently being studied in animal models and in human.
Collapse
Affiliation(s)
- Annarita Fiorillo
- Dipartimento di Scienze Biochimiche, University Sapienza, Rome, Italy
| | - Gianni Colotti
- Istituto di Biologia e Patologia Molecolari, CNR, Rome, Italy
- * E-mail: (AI), (GC)
| | - Alberto Boffi
- Dipartimento di Scienze Biochimiche, University Sapienza, Rome, Italy
- Istituto di Biologia e Patologia Molecolari, CNR, Rome, Italy
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche, Università di Roma “Sapienza”, Rome, Italy
| | - Paola Baiocco
- Dipartimento di Scienze Biochimiche, University Sapienza, Rome, Italy
| | - Andrea Ilari
- Istituto di Biologia e Patologia Molecolari, CNR, Rome, Italy
- * E-mail: (AI), (GC)
| |
Collapse
|
26
|
Abstract
SIGNIFICANCE Parasitic infections continue to be a major problem for global human health. Vaccines are practically not available and chemotherapy is highly unsatisfactory. One approach toward a novel antiparasitic drug development is to unravel pathways that may be suited as future targets. Parasitic organisms show a remarkable diversity with respect to the nature and functions of their main low-molecular-mass antioxidants and many of them developed pathways that do not have a counterpart in their mammalian hosts. RECENT ADVANCES Work of the last years disclosed the individual antioxidants employed by parasites and their distinct pathways. Entamoeba, Trichomonas, and Giardia directly use cysteine as main low-molecular-mass thiol but have divergent cysteine metabolisms. Malarial parasites rely exclusively on cysteine uptake and generate glutathione (GSH) as main free thiol as do metazoan parasites. Trypanosomes and Leishmania have a unique trypanothione-based thiol metabolism but employ individual mechanisms for their cysteine supply. In addition, some trypanosomatids synthesize ovothiol A and/or ascorbate. Various essential parasite enzymes such as trypanothione synthetase and trypanothione reductase in Trypanosomatids and the Schistosoma thioredoxin GSH reductase are currently intensively explored as drug target molecules. CRITICAL ISSUES Essentiality is a prerequisite but not a sufficient property of an enzyme to become a suited drug target. The availability of an appropriate in vivo screening system and many other factors are equally important. FUTURE DIRECTIONS The current organism-wide RNA-interference and proteome analyses are supposed to reveal many more interesting candidates for future drug development approaches directed against the parasite antioxidant defense systems.
Collapse
|
27
|
Flohé L. The trypanothione system and its implications in the therapy of trypanosomatid diseases. Int J Med Microbiol 2012; 302:216-20. [PMID: 22889611 DOI: 10.1016/j.ijmm.2012.07.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Biosynthesis and the use of trypanothione, a redox metabolite of parasitic trypanosomatids, are reviewed here with special emphasis on the development of trypanocidal drugs. This metabolic system is unique to and essential for the protozoal parasites. Selective inhibition of key elements of trypanothione metabolism, therefore, promises eradication of the parasites without affecting the host. Considering the metabolic importance and drugability of system components, inhibition of the enzymes for regeneration and de novo synthesis of trypanothione is rated as the most promising approach, while related peroxidases and redoxins are disregarded as targets because of limited chances to achieve selective inhibition. The organizational need to exploit the accumulating knowledge of trypanosomatid metabolism for medical practice is briefly addressed.
Collapse
Affiliation(s)
- Leopold Flohé
- Department of Chemistry, Otto-von-Guericke-Universität, Universitätsplatz 2, 39106 Magdeburg, Germany.
| |
Collapse
|
28
|
Saudagar P, Dubey VK. Cloning, expression, characterization and inhibition studies on trypanothione synthetase, a drug target enzyme, from Leishmania donovani. Biol Chem 2012; 392:1113-22. [PMID: 22050226 DOI: 10.1515/bc.2011.222] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Trypanothione synthetase, a validated drug target, synthesizes trypanothione from glutathione and spermidine. Here we report the gene cloning, expression, characterization and inhibition studies of trypanothione synthetase from Leishmania donovani (LdTryS). The purified recombinant LdTryS enzyme obeyed Michaelis-Menten kinetics. High substrate inhibition was observed with glutathione (K(m)=33.24 μm, k(cat)=1.3 s(-1), K(i)=866 μm). The enzyme shows simple hyperbolic kinetics with fixed glutathione concentration and with other substrates limiting K(m) values for Mg. ATP and spermidine of 14.2 μm and 139.6 μm, respectively. LdTryS was also screened for inhibitors. Tomatine, conessine, uvaol and betulin were identified as inhibitors of the enzyme and were tested for leishmanicidal activity. Finally, the effect of LdTryS inhibitors on redox homeostasis of the parasite gives a broader picture of their action against leishmaniasis.
Collapse
Affiliation(s)
- Prakash Saudagar
- Department of Biotechnology, Indian Institute of Technology Guwahati, Assam-781039, India
| | | |
Collapse
|
29
|
Olin-Sandoval V, González-Chávez Z, Berzunza-Cruz M, Martínez I, Jasso-Chávez R, Becker I, Espinoza B, Moreno-Sánchez R, Saavedra E. Drug target validation of the trypanothione pathway enzymes through metabolic modelling. FEBS J 2012; 279:1811-33. [DOI: 10.1111/j.1742-4658.2012.08557.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
30
|
Induction of oxidative stress in Trypanosoma brucei by the antitrypanosomal dihydroquinoline OSU-40. Antimicrob Agents Chemother 2012; 56:2428-34. [PMID: 22314522 DOI: 10.1128/aac.06386-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dihydroquinoline derivative OSU-40 (1-benzyl-1,2-dihydro-2,2,4-trimethylquinolin-6-yl acetate) is selectively potent against Trypanosma brucei rhodesiense in vitro (50% inhibitory concentration [IC(50)], 14 nM; selectivity index, 1,700) and has been proposed to cause the formation of reactive oxygen species (ROS) in African trypanosomes (J. Fotie et al., J. Med. Chem. 53:966-982, 2010). In the present study, we sought to provide further support for the hypothesis that OSU-40 kills trypanosomes through oxidative stress. Inducible RNA interference (RNAi) was applied to downregulate key enzymes in parasite antioxidant defense, including T. brucei trypanothione synthetase (TbTryS) and superoxide dismutase B (TbSODB). Both TbTryS RNAi-induced and TbSODB RNAi-induced cells showed impaired growth and increased sensitivity toward OSU-40 by 2.4-fold and 3.4-fold, respectively. Decreased expression of key parasite antioxidant enzymes was thus associated with increased sensitivity to OSU-40, consistent with the hypothesis that OSU-40 acts through oxidative stress. Finally, the dose-dependent formation of free radicals was observed after incubation of T. brucei with OSU-40 utilizing electron spin resonance (ESR) spectroscopy. These data support the notion that the mode of antitrypanosomal action for this class of compounds is to induce oxidative stress.
Collapse
|
31
|
Spinks D, Torrie LS, Thompson S, Harrison JR, Frearson JA, Read KD, Fairlamb AH, Wyatt PG, Gilbert IH. Design, synthesis and biological evaluation of Trypanosoma brucei trypanothione synthetase inhibitors. ChemMedChem 2012; 7:95-106. [PMID: 22162199 PMCID: PMC3320663 DOI: 10.1002/cmdc.201100420] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 11/04/2011] [Indexed: 11/29/2022]
Abstract
Trypanothione synthetase (TryS) is essential for the survival of the protozoan parasite Trypanosoma brucei, which causes human African trypanosomiasis. It is one of only a handful of chemically validated targets for T. brucei in vivo. To identify novel inhibitors of TbTryS we screened our in-house diverse compound library that contains 62,000 compounds. This resulted in the identification of six novel hit series of TbTryS inhibitors. Herein we describe the SAR exploration of these hit series, which gave rise to one common series with potency against the enzyme target. Cellular studies on these inhibitors confirmed on-target activity, and the compounds have proven to be very useful tools for further study of the trypanothione pathway in kinetoplastids.
Collapse
Affiliation(s)
- Daniel Spinks
- Drug Discovery Unit, Division of Biological Chemistry & Drug Discovery, College of Life Sciences, University of Dundee, Dundee, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Willert E, Phillips MA. Regulation and function of polyamines in African trypanosomes. Trends Parasitol 2011; 28:66-72. [PMID: 22192816 DOI: 10.1016/j.pt.2011.11.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 02/03/2023]
Abstract
The polyamine biosynthetic pathway is an important drug target for the treatment of human African trypanosomiasis (HAT), raising interest in understanding polyamine function and their mechanism of regulation. Polyamine levels are tightly controlled in mammalian cells, but similar regulatory mechanisms appear absent in trypanosomes. Instead trypanosomatid S-adenosylmethionine decarboxylase (AdoMetDC), which catalyzes a key step in the biosynthesis of the polyamine spermidine, is activated by dimerization with an inducible protein termed prozyme. Prozyme is an inactive paralog of the active AdoMetDC enzyme that evolved by gene duplication and is found only in the trypanosomatids. In Trypanosoma brucei, AdoMetDC activity appears to be controlled by regulation of prozyme protein levels, potentially at the translational level.
Collapse
Affiliation(s)
- Erin Willert
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Road, Dallas, TX 75390-9041, USA
| | | |
Collapse
|
33
|
Saudagar P, Dubey VK. Cloning, expression, characterization and inhibition studies on trypanothione synthetase, a drug target enzyme, from Leishmania donovani. Biol Chem 2011. [PMID: 22050226 DOI: 10.1515/bc-2011-222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Trypanothione synthetase, a validated drug target, synthesizes trypanothione from glutathione and spermidine. Here we report the gene cloning, expression, characterization and inhibition studies of trypanothione synthetase from Leishmania donovani (LdTryS). The purified recombinant LdTryS enzyme obeyed Michaelis-Menten kinetics. High substrate inhibition was observed with glutathione (K(m)=33.24 μm, k(cat)=1.3 s(-1), K(i)=866 μm). The enzyme shows simple hyperbolic kinetics with fixed glutathione concentration and with other substrates limiting K(m) values for Mg. ATP and spermidine of 14.2 μm and 139.6 μm, respectively. LdTryS was also screened for inhibitors. Tomatine, conessine, uvaol and betulin were identified as inhibitors of the enzyme and were tested for leishmanicidal activity. Finally, the effect of LdTryS inhibitors on redox homeostasis of the parasite gives a broader picture of their action against leishmaniasis.
Collapse
Affiliation(s)
- Prakash Saudagar
- Department of Biotechnology, Indian Institute of Technology Guwahati, Assam-781039, India
| | | |
Collapse
|
34
|
Flohé L. The trypanothione system and the opportunities it offers to create drugs for the neglected kinetoplast diseases. Biotechnol Adv 2011; 30:294-301. [PMID: 21620942 DOI: 10.1016/j.biotechadv.2011.05.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 05/06/2011] [Accepted: 05/09/2011] [Indexed: 12/20/2022]
Abstract
Parasitic trypanosomatids (Kinetoplastida) are the causative agents of devastating and hard-to-treat diseases such as African sleeping sickness, Chagas disease and various forms of Leishmaniasis. Altogether they affect > 30 Million patients, account for half a million fatalities p.a. and cause substantial economical problems in the Third World due to human morbidity and life stock losses. The design of efficacious and safe drugs is expected from inhibition of metabolic pathways that are unique and essential to the parasite and absent in the host. In this respect, the trypanothione system first detected in the insect-pathogenic trypanosomatid Crithidia fasciculata qualified as an attractive drug target area. The existence of the system in pathogenic relatives was established by homology cloning and PCR. The vital importance of the system was verified in Trypanosoma brucei by dsRNA technology or knock-out in other trypanosomatids, respectively, and is explained by its pivotal role in the parasite's antioxidant defense and DNA synthesis. The key system component is the bis-glutathionyl derivative of spermidine, trypanothione. It is the proximal reductant of tryparedoxin which substitutes for thioredoxin-, glutaredoxin- and glutathione-dependent reactions. Heterologous expression, functional characterization and crystallization of recombinant system components finally enable structure-based rational inhibitor design.
Collapse
Affiliation(s)
- Leopold Flohé
- Institute of Chemistry, Otto-von-Guericke-Universität, Universitätsplatz 2, D-39106 Magdeburg, Germany.
| |
Collapse
|
35
|
Fitzgerald MP, Madsen JM, Coleman MC, Teoh MLT, Westphal SG, Spitz DR, Radi R, Domann FE. Transgenic biosynthesis of trypanothione protects Escherichia coli from radiation-induced toxicity. Radiat Res 2010; 174:290-6. [PMID: 20726720 DOI: 10.1667/rr2235.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Trypanothione is a unique diglutathionyl-spermidine conjugate found in abundance in trypanosomes but not in other eukaryotes. Because trypanothione is a naturally occurring polyamine thiol reminiscent of the synthetic drug amifostine, it may be a useful protector against radiation and oxidative stress. For these reasons we hypothesized that trypanothione might serve as a radioprotective agent when produced in bacteria. To accomplish this objective, the trypanothione synthetase and reductase genes from T. cruzi were introduced into E. coli and their expression was verified by qPCR and immunoblotting. Trypanothione synthesis in bacteria, detected by HPLC, resulted in decreased intracellular levels of reactive oxygen species as determined by H(2)DCFDA oxidation. Moreover, E. coli genomic DNA was protected from radiation-induced DNA damage by 4.6-fold in the presence of trypanothione compared to control bacteria. Concordantly, the transgenic E. coli expressing trypanothione were 4.3-fold more resistant to killing by (137)Cs gamma radiation compared to E. coli devoid of trypanothione expression. Thus we have shown for the first time that E. coli can be genetically engineered to express the trypanothione biosynthetic pathway and produce trypanothione, which results in their radioresistance. These results warrant further research to explore the possibility of developing trypanothione as a novel radioprotective agent.
Collapse
Affiliation(s)
- Matthew P Fitzgerald
- Department of Radiation Oncology, Carver College of Medicine, and Holden Comprehensive Cancer Center, The University of Iowa Free Radical and Radiation Biology Program, Montevideo, Uruguay
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Roy N, Nageshan RK, Pallavi R, Chakravarthy H, Chandran S, Kumar R, Gupta AK, Singh RK, Yadav SC, Tatu U. Proteomics of Trypanosoma evansi infection in rodents. PLoS One 2010; 5:e9796. [PMID: 20339546 PMCID: PMC2842431 DOI: 10.1371/journal.pone.0009796] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Accepted: 02/18/2010] [Indexed: 11/19/2022] Open
Abstract
Background Trypanosoma evansi infections, commonly called ‘surra’, cause significant economic losses to livestock industry. While this infection is mainly restricted to large animals such as camels, donkeys and equines, recent reports indicate their ability to infect humans. There are no World Animal Health Organization (WAHO) prescribed diagnostic tests or vaccines available against this disease and the available drugs show significant toxicity. There is an urgent need to develop improved methods of diagnosis and control measures for this disease. Unlike its related human parasites T. brucei and T. cruzi whose genomes have been fully sequenced T. evansi genome sequence remains unavailable and very little efforts are being made to develop improved methods of prevention, diagnosis and treatment. With a view to identify potential diagnostic markers and drug targets we have studied the clinical proteome of T. evansi infection using mass spectrometry (MS). Methodology/Principal Findings Using shot-gun proteomic approach involving nano-lc Quadrupole Time Of Flight (QTOF) mass spectrometry we have identified over 160 proteins expressed by T. evansi in mice infected with camel isolate. Homology driven searches for protein identification from MS/MS data led to most of the matches arising from related Trypanosoma species. Proteins identified belonged to various functional categories including metabolic enzymes; DNA metabolism; transcription; translation as well as cell-cell communication and signal transduction. TCA cycle enzymes were strikingly missing, possibly suggesting their low abundances. The clinical proteome revealed the presence of known and potential drug targets such as oligopeptidases, kinases, cysteine proteases and more. Conclusions/Significance Previous proteomic studies on Trypanosomal infections, including human parasites T. brucei and T. cruzi, have been carried out from lab grown cultures. For T. evansi infection this is indeed the first ever proteomic study reported thus far. In addition to providing a glimpse into the biology of this neglected disease, our study is the first step towards identification of diagnostic biomarkers, novel drug targets as well as potential vaccine candidates to fight against T. evansi infections.
Collapse
Affiliation(s)
- Nainita Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Rani Pallavi
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Syama Chandran
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | | | | | | | - Utpal Tatu
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- * E-mail:
| |
Collapse
|
37
|
Torrie LS, Wyllie S, Spinks D, Oza SL, Thompson S, Harrison JR, Gilbert IH, Wyatt PG, Fairlamb AH, Frearson JA. Chemical validation of trypanothione synthetase: a potential drug target for human trypanosomiasis. J Biol Chem 2009; 284:36137-36145. [PMID: 19828449 PMCID: PMC2794729 DOI: 10.1074/jbc.m109.045336] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 09/29/2009] [Indexed: 11/06/2022] Open
Abstract
In the search for new therapeutics for the treatment of human African trypanosomiasis, many potential drug targets in Trypanosoma brucei have been validated by genetic means, but very few have been chemically validated. Trypanothione synthetase (TryS; EC 6.3.1.9; spermidine/glutathionylspermidine:glutathione ligase (ADP-forming)) is one such target. To identify novel inhibitors of T. brucei TryS, we developed an in vitro enzyme assay, which was amenable to high throughput screening. The subsequent screen of a diverse compound library resulted in the identification of three novel series of TryS inhibitors. Further chemical exploration resulted in leads with nanomolar potency, which displayed mixed, uncompetitive, and allosteric-type inhibition with respect to spermidine, ATP, and glutathione, respectively. Representatives of all three series inhibited growth of bloodstream T. brucei in vitro. Exposure to one of our lead compounds (DDD86243; 2 x EC(50) for 72 h) decreased intracellular trypanothione levels to <10% of wild type. In addition, there was a corresponding 5-fold increase in the precursor metabolite, glutathione, providing strong evidence that DDD86243 was acting on target to inhibit TryS. This was confirmed with wild-type, TryS single knock-out, and TryS-overexpressing cell lines showing expected changes in potency to DDD86243. Taken together, these data provide initial chemical validation of TryS as a drug target in T. brucei.
Collapse
Affiliation(s)
- Leah S Torrie
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Susan Wyllie
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Daniel Spinks
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Sandra L Oza
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Stephen Thompson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Justin R Harrison
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Ian H Gilbert
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Paul G Wyatt
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Alan H Fairlamb
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | - Julie A Frearson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom.
| |
Collapse
|
38
|
Herbas MS, Thekisoe OMM, Inoue N, Xuan X, Arai H, Suzuki H. The effect of alpha-tocopherol transfer protein gene disruption on Trypanosoma congolense infection in mice. Free Radic Biol Med 2009; 47:1408-13. [PMID: 19695323 DOI: 10.1016/j.freeradbiomed.2009.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 08/11/2009] [Accepted: 08/11/2009] [Indexed: 01/17/2023]
Abstract
At present 15 to 20 million people are estimated to be infected with pathogenic trypanosome parasites worldwide, mainly in developing countries. There are a number of factors that affect the severity of trypanosomiasis, including the nutritional status of the host. However, the relationship between micronutrient levels and trypanosomiasis outcome has yet to be reported in detail. Here, we demonstrate that the inhibition of alpha-tocopherol transfer protein, a determinant of the vitamin E concentration in host circulation, confers resistance to Trypanosoma congolense infection, evidently owing to oxidative damage to parasite DNA. These results suggest that transient inhibition of alpha-tocopherol transfer gene activity could possibly be exploited as a strategy for both the prevention and the treatment of trypanosomiasis.
Collapse
Affiliation(s)
- Maria Shirley Herbas
- Research Unit for Functional Genomics, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-13, Inada, Obihiro 080-8555, Japan
| | | | | | | | | | | |
Collapse
|
39
|
Abstract
The protozoan parasitesTrypanosoma bruceiandTrypanosoma cruziare the causative agents of African trypanosomiasis and Chagas disease, respectively. These are debilitating infections that exert a considerable health burden on some of the poorest people on the planet. Treatment of trypanosome infections is dependent on a small number of drugs that have limited efficacy and can cause severe side effects. Here, we review the properties of these drugs and describe new findings on their modes of action and the mechanisms by which resistance can arise. We further outline how a greater understanding of parasite biology is being exploited in the search for novel chemotherapeutic agents. This effort is being facilitated by new research networks that involve academic and biotechnology/pharmaceutical organisations, supported by public–private partnerships, and are bringing a new dynamism and purpose to the search for trypanocidal agents.
Collapse
|
40
|
Smith TK, Vasileva N, Gluenz E, Terry S, Portman N, Kramer S, Carrington M, Michaeli S, Gull K, Rudenko G. Blocking variant surface glycoprotein synthesis in Trypanosoma brucei triggers a general arrest in translation initiation. PLoS One 2009; 4:e7532. [PMID: 19855834 PMCID: PMC2762041 DOI: 10.1371/journal.pone.0007532] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 09/22/2009] [Indexed: 01/22/2023] Open
Abstract
Background The African trypanosome Trypanosoma brucei is covered with a dense layer of Variant Surface Glycoprotein (VSG), which protects it from lysis by host complement via the alternative pathway in the mammalian bloodstream. Blocking VSG synthesis by the induction of VSG RNAi triggers an unusually precise precytokinesis cell-cycle arrest. Methodology/Principal Findings Here, we characterise the cells arrested after the induction of VSG RNAi. We were able to rescue the VSG221 RNAi induced cell-cycle arrest through expression of a second different VSG (VSG117 which is not recognised by the VSG221 RNAi) from the VSG221 expression site. Metabolic labeling of the arrested cells showed that blocking VSG synthesis triggered a global translation arrest, with total protein synthesis reduced to less than 1–4% normal levels within 24 hours of induction of VSG RNAi. Analysis by electron microscopy showed that the translation arrest was coupled with rapid disassociation of ribosomes from the endoplasmic reticulum. Polysome analysis showed a drastic decrease in polysomes in the arrested cells. No major changes were found in levels of transcription, total RNA transcript levels or global amino acid concentrations in the arrested cells. Conclusions The cell-cycle arrest phenotype triggered by the induction of VSG221 RNAi is not caused by siRNA toxicity, as this arrest can be alleviated if a second different VSG is inserted downstream of the active VSG221 expression site promoter. Analysis of polysomes in the stalled cells showed that the translation arrest is mediated at the level of translation initiation rather than elongation. The cell-cycle arrest induced in the presence of a VSG synthesis block is reversible, suggesting that VSG synthesis and/or trafficking to the cell surface could be monitored during the cell-cycle as part of a specific cell-cycle checkpoint.
Collapse
Affiliation(s)
- Terry K. Smith
- Centre for Biomolecular Sciences, University of St. Andrews, Fife, Scotland, United Kingdom
| | - Nadina Vasileva
- The Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Eva Gluenz
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Stephen Terry
- The Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Neil Portman
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Susanne Kramer
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Gloria Rudenko
- The Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
- * E-mail:
| |
Collapse
|
41
|
Overexpression of mitochondrial Leishmania major ascorbate peroxidase enhances tolerance to oxidative stress-induced programmed cell death and protein damage. EUKARYOTIC CELL 2009; 8:1721-31. [PMID: 19749178 DOI: 10.1128/ec.00198-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Ascorbate peroxidase from Leishmania major (LmAPX) is one of the key enzymes for scavenging of reactive oxygen species generated from the mitochondrial respiratory chain. We have investigated whether mitochondrial LmAPX has any role in oxidative stress-induced apoptosis. The measurement of reduced glutathione (GSH) and protein carbonyl contents in cellular homogenates indicates that overexpression of LmAPX protects Leishmania cells against depletion of GSH and oxidative damage of proteins by H(2)O(2) or camptothecin (CPT) treatment. Confocal microscopy and fluorescence spectroscopy data have revealed that the intracellular elevation of Ca(2+) attained by the LmAPX-overexpressing cells was always below that attained in control cells. Flow cytometry assay data and confocal microscopy observation strongly suggest that LmAPX overexpression protects cells from H(2)O(2)-induced mitochondrial membrane depolarization as well as ATP decrease. Western blot data suggest that overexpression of LmAPX shields against H(2)O(2)- or CPT-induced cytochrome c and endonuclease G release from mitochondria and subsequently their accumulation in the cytoplasm. Caspase activity assay by flow cytometry shows a lower level of caspase-like protease activity in LmAPX-overexpressing cells under apoptotic stimuli. The data on phosphatidylserine exposed on the cell surface and DNA fragmentation results show that overexpression of LmAPX renders the Leishmania cells more resistant to apoptosis provoked by H(2)O(2) or CPT treatment. Taken together, these results indicate that constitutive overexpression of LmAPX in the mitochondria of L. major prevents cells from the deleterious effects of oxidative stress, that is, mitochondrial dysfunction and cellular death.
Collapse
|
42
|
Wyllie S, Oza SL, Patterson S, Spinks D, Thompson S, Fairlamb AH. Dissecting the essentiality of the bifunctional trypanothione synthetase-amidase in Trypanosoma brucei using chemical and genetic methods. Mol Microbiol 2009; 74:529-40. [PMID: 19558432 PMCID: PMC2784880 DOI: 10.1111/j.1365-2958.2009.06761.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The bifunctional trypanothione synthetase-amidase (TRYS) comprises two structurally distinct catalytic domains for synthesis and hydrolysis of trypanothione (N1,N8-bis(glutathionyl)spermidine). This unique dithiol plays a pivotal role in thiol-redox homeostasis and in defence against chemical and oxidative stress in trypanosomatids. A tetracycline-dependent conditional double knockout of TRYS (cDKO) was generated in bloodstream Trypanosoma brucei. Culture of cDKO parasites without tetracycline induction resulted in loss of trypanothione and accumulation of glutathione, followed by growth inhibition and cell lysis after 6 days. In the absence of inducer, cDKO cells were unable to infect mice, confirming that this enzyme is essential for virulence in vivo as well as in vitro. To establish whether both enzymatic functions were essential, an amidase-dead mutant cDKO line was generated. In the presence of inducer, this line showed decreased growth in vitro and decreased virulence in vivo, indicating that the amidase function is not absolutely required for viability. The druggability of TRYS was assessed using a potent small molecule inhibitor developed in our laboratory. Growth inhibition correlated in rank order cDKO, single KO, wild-type and overexpressing lines and produced the predicted biochemical phenotype. The synthetase function of TRYS is thus unequivocally validated as a drug target by both chemical and genetic methods.
Collapse
Affiliation(s)
- Susan Wyllie
- Division of Biological Chemistry and Drug Discovery, Wellcome Trust Biocentre, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK
| | | | | | | | | | | |
Collapse
|
43
|
RNA interference-mediated silencing of ornithine decarboxylase and spermidine synthase genes in Trypanosoma brucei provides insight into regulation of polyamine biosynthesis. EUKARYOTIC CELL 2009; 8:747-55. [PMID: 19304951 DOI: 10.1128/ec.00047-09] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Polyamine biosynthesis is a drug target for the treatment of African sleeping sickness; however, mechanisms regulating the pathway in Trypanosoma brucei are not well understood. Recently, we showed that RNA interference (RNAi)-mediated gene silencing or the inhibition of S-adenosylmethionine decarboxylase (AdoMetDC) led to the upregulation of the AdoMetDC activator, prozyme, and ornithine decarboxylase (ODC) proteins. To determine if this regulatory response is specific to AdoMetDC, we studied the effects of the RNAi-induced silencing of the spermidine synthase (SpdSyn) and ODC genes in bloodstream form T. brucei. The knockdown of either gene product led to the depletion of the polyamine and trypanothione pools and to cell death. Decarboxylated AdoMet levels were elevated, while AdoMet was not affected. There was no significant effect on the protein levels of other polyamine pathway enzymes. The treatment of parasites with the ODC inhibitor alpha-difluoromethylornithine gave similar results to those observed for ODC knockdown. Thus, the cellular response to the loss of AdoMetDC activity is distinctive, suggesting that AdoMetDC activity controls the expression levels of the other spermidine biosynthetic enzymes. RNAi-mediated cell death occurred more rapidly for ODC than for SpdSyn. Further, the ODC RNAi cells were rescued by putrescine, but not spermidine, suggesting that the depletion of both putrescine and spermidine is more detrimental than the depletion of spermidine alone. This finding may contribute to the effectiveness of ODC as a target for the treatment of African sleeping sickness, thus providing important insight into the mechanism of action of a key antitrypanosomal agent.
Collapse
|
44
|
Romao S, Castro H, Sousa C, Carvalho S, Tomás AM. The cytosolic tryparedoxin of Leishmania infantum is essential for parasite survival. Int J Parasitol 2008; 39:703-11. [PMID: 19135056 DOI: 10.1016/j.ijpara.2008.11.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 11/05/2008] [Accepted: 11/13/2008] [Indexed: 11/28/2022]
Abstract
Leishmania infantum cytosolic tryparedoxin (LiTXN1) can be regarded as a potential candidate for drug targeting. This redox active molecule, which belongs to the thioredoxin superfamily, is one constituent of the hydroperoxide elimination cascade in L. infantum and may also be involved in other cellular processes such as DNA synthesis or host-parasite interaction. In order to validate LiTXN1 as a drug target we have employed a gene replacement strategy. We observed that substitution of both chromosomal LiTXN1 alleles was only possible upon parasite complementation with an episomal copy of the gene. Furthermore, contrary to control parasites carrying the empty vector, both the insect and the mammalian stages of L. infantum retained the episomal copy of LiTXN1 in the absence of drug pressure. These results confirm the essentiality of LiTXN1 throughout the life cycle of the parasite, namely in the disease-causing amastigote stage. In addition, the data obtained showed that disruption of one allele of this gene leads only to a 25% reduction in the expression of LiTXN1. Even though this does not affect promastigote growth and susceptibility to hydrogen peroxide, ex vivo infection assays suggest that wild-type levels of LiTXN1 are required for optimal L. infantum virulence.
Collapse
Affiliation(s)
- Susana Romao
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
| | | | | | | | | |
Collapse
|
45
|
Oza SL, Chen S, Wyllie S, Coward JK, Fairlamb AH. ATP-dependent ligases in trypanothione biosynthesis--kinetics of catalysis and inhibition by phosphinic acid pseudopeptides. FEBS J 2008; 275:5408-21. [PMID: 18959765 PMCID: PMC2702004 DOI: 10.1111/j.1742-4658.2008.06670.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Glutathionylspermidine is an intermediate formed in the biosynthesis of trypanothione, an essential metabolite in defence against chemical and oxidative stress in the Kinetoplastida. The kinetic mechanism for glutathionylspermidine synthetase (EC 6.3.1.8) from Crithidia fasciculata (CfGspS) obeys a rapid equilibrium random ter-ter model with kinetic constants KGSH = 609 μm, KSpd = 157 μm and KATP = 215 μm. Phosphonate and phosphinate analogues of glutathionylspermidine, previously shown to be potent inhibitors of GspS from Escherichia coli, are equally potent against CfGspS. The tetrahedral phosphonate acts as a simple ground state analogue of glutathione (GSH) (Ki ∼ 156 μm), whereas the phosphinate behaves as a stable mimic of the postulated unstable tetrahedral intermediate. Kinetic studies showed that the phosphinate behaves as a slow-binding bisubstrate inhibitor [competitive with respect to GSH and spermidine (Spd)] with rate constants k3 (on rate) = 6.98 × 104m−1·s−1 and k4 (off rate) = 1.3 × 10−3 s−1, providing a dissociation constant Ki = 18.6 nm. The phosphinate analogue also inhibited recombinant trypanothione synthetase (EC 6.3.1.9) from C. fasciculata, Leishmania major, Trypanosoma cruzi and Trypanosoma brucei with Kiapp values 20–40-fold greater than that of CfGspS. This phosphinate analogue remains the most potent enzyme inhibitor identified to date, and represents a good starting point for drug discovery for trypanosomiasis and leishmaniasis.
Collapse
Affiliation(s)
- Sandra L Oza
- Division of Biological Chemistry and Drug Discovery, Wellcome Trust Biocentre, College of Life Sciences, University of Dundee, UK
| | | | | | | | | |
Collapse
|
46
|
Willert EK, Phillips MA. Regulated expression of an essential allosteric activator of polyamine biosynthesis in African trypanosomes. PLoS Pathog 2008; 4:e1000183. [PMID: 18949025 PMCID: PMC2562514 DOI: 10.1371/journal.ppat.1000183] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 09/23/2008] [Indexed: 12/11/2022] Open
Abstract
Trypanosoma brucei is the causative agent of African sleeping sickness. The polyamine biosynthetic pathway has the distinction of being the target of the only clinically proven anti-trypanosomal drug with a known mechanism of action. Polyamines are essential for cell growth, and their metabolism is extensively regulated. However, trypanosomatids appear to lack the regulatory control mechanisms described in other eukaryotic cells. In T. brucei, S-adenosylmethionine decarboxylase (AdoMetDC) and ornithine decarboxylase (ODC) are required for the synthesis of polyamines and also for the unique redox-cofactor trypanothione. Further, trypanosomatid AdoMetDC is activated by heterodimer formation with a catalytically dead homolog termed prozyme, found only in these species. To study polyamine regulation in T. brucei, we generated inducible AdoMetDC RNAi and prozyme conditional knockouts in the mammalian blood form stage. Depletion of either protein led to a reduction in spermidine and trypanothione and to parasite death, demonstrating that prozyme activation of AdoMetDC is essential. Under typical growth conditions, prozyme concentration is limiting in comparison to AdoMetDC. However, both prozyme and ODC protein levels were significantly increased relative to stable transcript levels by knockdown of AdoMetDC or its chemical inhibition. Changes in protein stability do not appear to account for the increased steady-state protein levels, as both enzymes are stable in the presence of cycloheximide. These observations suggest that prozyme and ODC are translationally regulated in response to perturbations in the pathway. In conclusion, we describe the first evidence for regulation of polyamine biosynthesis in T. brucei and we demonstrate that the unique regulatory subunit of AdoMetDC is a key component of this regulation. The data support ODC and AdoMetDC as the key control points in the pathway and the likely rate-limiting steps in polyamine biosynthesis.
Collapse
Affiliation(s)
- Erin K. Willert
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Margaret A. Phillips
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- * E-mail:
| |
Collapse
|
47
|
Structural and mechanistic insights into type II trypanosomatid tryparedoxin-dependent peroxidases. Biochem J 2008; 414:375-81. [PMID: 18522537 PMCID: PMC2552391 DOI: 10.1042/bj20080889] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
TbTDPX (Trypanosoma brucei tryparedoxin-dependent peroxidase) is a genetically validated drug target in the fight against African sleeping sickness. Despite its similarity to members of the GPX (glutathione peroxidase) family, TbTDPX2 is functional as a monomer, lacks a selenocysteine residue and relies instead on peroxidatic and resolving cysteine residues for catalysis and uses tryparedoxin rather than glutathione as electron donor. Kinetic studies indicate a saturable Ping Pong mechanism, unlike selenium-dependent GPXs, which display infinite Km and Vmax values. The structure of the reduced enzyme at 2.1 Å (0.21 nm) resolution reveals that the catalytic thiol groups are widely separated [19 Å (0.19 nm)] and thus unable to form a disulphide bond without a large conformational change in the secondary-structure architecture, as reported for certain plant GPXs. A model of the oxidized enzyme structure is presented and the implications for small-molecule inhibition are discussed.
Collapse
|
48
|
Irigoín F, Cibils L, Comini MA, Wilkinson SR, Flohé L, Radi R. Insights into the redox biology of Trypanosoma cruzi: Trypanothione metabolism and oxidant detoxification. Free Radic Biol Med 2008; 45:733-42. [PMID: 18588970 DOI: 10.1016/j.freeradbiomed.2008.05.028] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 05/24/2008] [Accepted: 05/28/2008] [Indexed: 10/22/2022]
Abstract
Trypanosoma cruzi is the etiologic agent of Chagas' disease, an infection that affects several million people in Latin America. With no immediate prospect of a vaccine and problems associated with current chemotherapies, the development of new treatments is an urgent priority. Several aspects of the redox metabolism of this parasite differ enough from those in the mammalian host to be considered targets for drug development. Here, we review the information about a trypanosomatid-specific molecule centrally involved in redox metabolism, the dithiol trypanothione, and the main effectors of cellular antioxidant defense. We focus mainly on data from T. cruzi, making comparisons with other trypanosomatids whenever possible. In these parasites trypanothione participates in crucial thiol-disulfide exchange reactions and serves as electron donor in different metabolic pathways, from synthesis of DNA precursors to oxidant detoxification. Interestingly, the levels of several enzymes involved in trypanothione metabolism and oxidant detoxification increase during the transformation of T. cruzi to its mammalian-infective form and the overexpression of some of them has been associated with increased resistance to macrophage-dependent oxidative killing. Together, the evidence suggests a central role of the trypanothione-dependent antioxidant systems in the infection process.
Collapse
Affiliation(s)
- Florencia Irigoín
- Departmento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Uruguay
| | | | | | | | | | | |
Collapse
|
49
|
Abstract
This article provides an overview about the recent advances in the dissection of the peroxide metabolism of Trypanosomatidae. This family of protozoan organisms comprises the medically relevant parasites Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. Over the past 10 years, three major families of peroxidases have been identified in these organisms: (a) 2-cysteine peroxiredoxins, (b) nonselenium glutathione peroxidases, and (c) ascorbate peroxidases. In trypanosomatids, these enzymes display the unique feature of using reducing equivalents derived from trypanothione, a dithiol found exclusively in these protozoa. The electron transfer between trypanothione and the peroxidases is mediated by a redox shuttle, which can either be tryparedoxin, ascorbate, or even glutathione. The preference for the intermediate molecule differs among each peroxidase and so does the specificity for the peroxide substrate. These observations, added to the fact that these peroxidases are distributed throughout different subcellular compartments, point to the existence of an elaborate peroxide metabolism in trypanosomatids. With the completion of the trypanosomatids genome, other molecules displaying peroxidase activity might be added to this list in the future.
Collapse
Affiliation(s)
- Helena Castro
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | | |
Collapse
|
50
|
Metabolic control analysis: a tool for designing strategies to manipulate metabolic pathways. J Biomed Biotechnol 2008; 2008:597913. [PMID: 18629230 PMCID: PMC2447884 DOI: 10.1155/2008/597913] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 01/16/2008] [Accepted: 03/26/2008] [Indexed: 02/06/2023] Open
Abstract
The traditional experimental approaches used for changing the flux or the concentration of a particular metabolite of a metabolic pathway have been mostly based on the inhibition or over-expression of the presumed rate-limiting step. However, the attempts to manipulate a metabolic pathway by following such approach have proved to be unsuccessful. Metabolic Control Analysis (MCA) establishes how to determine, quantitatively, the degree of control that a given enzyme exerts on flux and on the concentration of metabolites, thus substituting the intuitive, qualitative concept of rate limiting step. Moreover, MCA helps to understand (i) the underlying mechanisms by which a given enzyme exerts high or low control and (ii) why the control of the pathway is shared by several pathway enzymes and transporters. By applying MCA it is possible to identify the steps that should be modified to achieve a successful alteration of flux or metabolite concentration in pathways of biotechnological (e.g., large scale metabolite production) or clinical relevance (e.g., drug therapy). The different MCA experimental approaches developed for the determination of the flux-control distribution in several pathways are described. Full understanding of the pathway properties when is working under a variety of conditions can help to attain a successful manipulation of flux and metabolite concentration.
Collapse
|