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Carter NS, Kawasaki Y, Nahata SS, Elikaee S, Rajab S, Salam L, Alabdulal MY, Broessel KK, Foroghi F, Abbas A, Poormohamadian R, Roberts SC. Polyamine Metabolism in Leishmania Parasites: A Promising Therapeutic Target. Med Sci (Basel) 2022; 10:24. [PMID: 35645240 PMCID: PMC9149861 DOI: 10.3390/medsci10020024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/18/2022] [Accepted: 04/18/2022] [Indexed: 12/30/2022] Open
Abstract
Parasites of the genus Leishmania cause a variety of devastating and often fatal diseases in humans and domestic animals worldwide. The need for new therapeutic strategies is urgent because no vaccine is available, and treatment options are limited due to a lack of specificity and the emergence of drug resistance. Polyamines are metabolites that play a central role in rapidly proliferating cells, and recent studies have highlighted their critical nature in Leishmania. Numerous studies using a variety of inhibitors as well as gene deletion mutants have elucidated the pathway and routes of transport, revealing unique aspects of polyamine metabolism in Leishmania parasites. These studies have also shed light on the significance of polyamines for parasite proliferation, infectivity, and host-parasite interactions. This comprehensive review article focuses on the main polyamine biosynthetic enzymes: ornithine decarboxylase, S-adenosylmethionine decarboxylase, and spermidine synthase, and it emphasizes recent discoveries that advance these enzymes as potential therapeutic targets against Leishmania parasites.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Sigrid C. Roberts
- School of Pharmacy, Pacific University Oregon, Hillsboro, OR 97123, USA; (N.S.C.); (Y.K.); (S.S.N.); (S.E.); (S.R.); (L.S.); (M.Y.A.); (K.K.B.); (F.F.); (A.A.); (R.P.)
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Barbolla I, Hernández-Suárez L, Quevedo-Tumailli V, Nocedo-Mena D, Arrasate S, Dea-Ayuela MA, González-Díaz H, Sotomayor N, Lete E. Palladium-mediated synthesis and biological evaluation of C-10b substituted Dihydropyrrolo[1,2-b]isoquinolines as antileishmanial agents. Eur J Med Chem 2021; 220:113458. [PMID: 33901901 DOI: 10.1016/j.ejmech.2021.113458] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/12/2021] [Accepted: 04/05/2021] [Indexed: 11/26/2022]
Abstract
The development of new molecules for the treatment of leishmaniasis is, a neglected parasitic disease, is urgent as current anti-leishmanial therapeutics are hampered by drug toxicity and resistance. The pyrrolo[1,2-b]isoquinoline core was selected as starting point, and palladium-catalyzed Heck-initiated cascade reactions were developed for the synthesis of a series of C-10 substituted derivatives. Their in vitro leishmanicidal activity against visceral (L. donovani) and cutaneous (L. amazonensis) leishmaniasis was evaluated. The best activity was found, in general, for the 10-arylmethyl substituted pyrroloisoquinolines. In particular, 2ad (IC50 = 3.30 μM, SI > 77.01) and 2bb (IC50 = 3.93 μM, SI > 58.77) were approximately 10-fold more potent and selective than the drug of reference (miltefosine), against L. amazonensis on in vitro promastigote assays, while 2ae was the more active compound in the in vitro amastigote assays (IC50 = 33.59 μM, SI > 8.93). Notably, almost all compounds showed low cytotoxicity, CC50 > 100 μg/mL in J774 cells, highest tested dose. In addition, we have developed the first Perturbation Theory Machine Learning (PTML) algorithm able to predict simultaneously multiple biological activity parameters (IC50, Ki, etc.) vs. any Leishmania species and target protein, with high values of specificity (>98%) and sensitivity (>90%) in both training and validation series. Therefore, this model may be useful to reduce time and assay costs (material and human resources) in the drug discovery process.
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Affiliation(s)
- Iratxe Barbolla
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad Del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080, Bilbao, Spain
| | - Leidi Hernández-Suárez
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad Del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080, Bilbao, Spain
| | - Viviana Quevedo-Tumailli
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad Del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080, Bilbao, Spain; RNASA-IMEDIR, Computer Science Faculty, University of A Coruña, 15071, A Coruña, Spain; Universidad Estatal Amazónica UEA, Puyo, 160150, Pastaza, Ecuador
| | - Deyani Nocedo-Mena
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad Del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080, Bilbao, Spain
| | - Sonia Arrasate
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad Del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080, Bilbao, Spain
| | - María Auxiliadora Dea-Ayuela
- Departamento de Farmacia, Facultad de Ciencias de La Salud, Universidad CEU Cardenal Herrera, Edificio Seminario S/n, 46113, Moncada, Valencia, Spain
| | - Humberto González-Díaz
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad Del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080, Bilbao, Spain; Basque Center for Biophysics CSIC-UPV/EHU, University of the Basque Country UPV/EHU, 48940, Bilbao, Spain; IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Nuria Sotomayor
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad Del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080, Bilbao, Spain.
| | - Esther Lete
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad Del País Vasco / Euskal Herriko Unibertsitatea UPV/EHU, Apdo. 644, 48080, Bilbao, Spain.
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Hazra S, Ghosh S, Hazra B. Phytochemicals With Antileishmanial Activity. STUDIES IN NATURAL PRODUCTS CHEMISTRY 2017. [DOI: 10.1016/b978-0-444-63931-8.00008-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
In trypanosomatids, polyamine and trypanothione pathways can be considered as a whole unique metabolism, where most enzymes are essential for parasitic survival and infectivity. Leishmania parasites and all the other members of the Trypanosomatids family depend on polyamines for growth and survival: the enzymes involved in the synthesis and utilization of spermidine and trypanothione, i.e., arginase, ornithine decarboxylase, S-adenosylmethionine decarboxylase, spermidine synthase and in particular trypanothione synthetase-amidase, trypanothione reductase and tryparedoxin-dependent peroxidase are promising targets for drug development. This review deals with recent structure-based studies on these enzymes, aimed at the discovery of inhibitors of this pathway.
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Stiles JK, Hicock PI, Shah PH, Meade JC. Genomic organization, transcription, splicing and gene regulation inLeishmania. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.1999.11813485] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Das M, Singh S, Dubey VK. Novel Inhibitors of Ornithine Decarboxylase ofLeishmaniaParasite (LdODC): The Parasite ResistsLdODC Inhibition by Overexpression of Spermidine Synthase. Chem Biol Drug Des 2015; 87:352-60. [DOI: 10.1111/cbdd.12665] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/03/2015] [Accepted: 09/07/2015] [Indexed: 11/27/2022]
Affiliation(s)
- Mousumi Das
- Department of Biosciences and Bioengineering; Indian Institute of Technology Guwahati; Assam 781039 India
| | - Shalini Singh
- Department of Biosciences and Bioengineering; Indian Institute of Technology Guwahati; Assam 781039 India
| | - Vikash Kumar Dubey
- Department of Biosciences and Bioengineering; Indian Institute of Technology Guwahati; Assam 781039 India
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Singh AK, Roberts S, Ullman B, Madhubala R. A quantitative proteomic screen to identify potential drug resistance mechanism in α-difluoromethylornithine (DFMO) resistant Leishmania donovani. J Proteomics 2014; 102:44-59. [PMID: 24631822 DOI: 10.1016/j.jprot.2014.02.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/22/2014] [Accepted: 02/25/2014] [Indexed: 12/13/2022]
Abstract
UNLABELLED Visceral leishmaniasis (VL) caused by Leishmania donovani is a systemic protozoan disease that is fatal if left untreated. The promastigote form of L. donovani is sensitive to growth inhibition by dl-α-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase (ODC), the first enzyme of the polyamine biosynthetic pathway. Exposure of a wild type (DI700) cell population to gradually increasing concentrations of DFMO resulted in the selection of a strain of Leishmania (DFMO-16), which was capable of proliferating in 16mM DFMO. To elucidate the molecular basis for this resistance, we undertook a comparative proteomic analysis of DFMO-resistant/sensitive parasites using isobaric tagging for relative and absolute quantification (iTRAQ/LC-MS/MS). Out of the 101 proteins identified in at least 2 of the 3 independent experiments, 82 proteins are 1.5- to 44.0-fold more abundant in DFMO-resistant strain (DFMO-16) while 19 are 2- to 5.0-fold less abundant as compared to the wild-type (DI700) parasites. Proteins with 2-fold or greater abundance in the DFMO-resistant strain include free radical detoxification, polyamine and trypanothione metabolic proteins, proteins involved in metabolism, intracellular survival and proteolysis, elongation factors, signaling molecules and mitochondrial transporters, and many with no annotated function. Differentially modulated proteins contribute to our understanding of molecular mechanism of DFMO-resistance and have the potential to act as biomarkers. BIOLOGICAL SIGNIFICANCE This study will facilitate a deeper understanding of the phenomenon of acquired drug resistance and possible biomarkers in Leishmania against antiparasitic drug DFMO. Also it will provide information about the metabolic pathways modulated in resistant parasites as an adaptation mechanism to counter drugs. Studies like this are important to safeguard the efficacy of a limited repertoire of anti-parasitic drugs, and to lead the development of new drugs and drug combinations.
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Affiliation(s)
- Alok Kumar Singh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Buddy Ullman
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, USA
| | - Rentala Madhubala
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
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Hazra S, Ghosh S, Das Sarma M, Sharma S, Das M, Saudagar P, Prajapati VK, Dubey VK, Sundar S, Hazra B. Evaluation of a diospyrin derivative as antileishmanial agent and potential modulator of ornithine decarboxylase of Leishmania donovani. Exp Parasitol 2013; 135:407-13. [PMID: 23973194 DOI: 10.1016/j.exppara.2013.07.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 05/31/2013] [Accepted: 07/19/2013] [Indexed: 10/26/2022]
Abstract
World health organization has called for academic research and development of new chemotherapeutic strategies to overcome the emerging resistance and side effects exhibited by the drugs currently used against leishmaniasis. Diospyrin, a bis-naphthoquinone isolated from Diospyros montana Roxb., and its semi-synthetic derivatives, were reported for inhibitory activity against protozoan parasites including Leishmania. Presently, we have investigated the antileishmanial effect of a di-epoxide derivative of diospyrin (D17), both in vitro and in vivo. Further, the safety profile of D17 was established by testing its toxicity against normal macrophage cells (IC₅₀∼20.7 μM), and also against normal BALB/c mice in vivo. The compound showed enhanced activity (IC₅₀∼7.2 μM) as compared to diospyrin (IC₅₀∼12.6 μM) against Leishmania donovani promastigotes. Again, D17 was tested on L. donovani BHU1216 isolated from a sodium stibogluconate-unresponsive patient, and exhibited selective inhibition of the intracellular amastigotes (IC₅₀∼0.18 μM). Also, treatment of infected BALB/c mice with D17 at 2mg/kg/day reduced the hepatic parasite load by about 38%. Subsequently, computational docking studies were undertaken on selected enzymes of trypanothione metabolism, viz. trypanothione reductase (TryR) and ornithine decarboxylase (ODC), followed by the enzyme kinetics, where D17 demonstrated non-competitive inhibition of the L. donovani ODC, but could not inhibit TryR.
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Affiliation(s)
- Sudipta Hazra
- Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700 032, India
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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.
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Chakraborty D, Saravanan P, Patra S, Dubey VK. Studies on ornithine decarboxylase of Leishmania donovani: structure modeling and inhibitor docking. Med Chem Res 2012. [DOI: 10.1007/s00044-012-0035-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Colotti G, Ilari A. Polyamine metabolism in Leishmania: from arginine to trypanothione. Amino Acids 2010; 40:269-85. [PMID: 20512387 DOI: 10.1007/s00726-010-0630-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 05/13/2010] [Indexed: 12/20/2022]
Abstract
Polyamines (PAs) are essential metabolites in eukaryotes, participating in a variety of proliferative processes, and in trypanosomatid protozoa play an additional role in the synthesis of the critical thiol trypanothione. The PAs are synthesized by a metabolic process which involves arginase (ARG), which catalyzes the enzymatic hydrolysis of L-arginine (L-Arg) to L-ornithine and urea, and ornithine decarboxylase (ODC), which catalyzes the enzymatic decarboxylation of L-ornithine in putrescine. The S-adenosylmethionine decarboxylase (AdoMetDC) catalyzes the irreversible decarboxylation of S-adenosylmethionine (AdoMet), generating the decarboxylated S-adenosylmethionine (dAdoMet), which is a substrate, together with putrescine, for spermidine synthase (SpdS). Leishmania parasites and all the other members of the trypanosomatid family depend on spermidine for growth and survival. They can synthesize PAs and polyamine precursors, and also scavenge them from the microenvironment, using specific transporters. In addition, Trypanosomatids have a unique thiol-based metabolism, in which trypanothione (N1-N8-bis(glutathionyl)spermidine, T(SH)(2)) and trypanothione reductase (TR) replace many of the antioxidant and metabolic functions of the glutathione/glutathione reductase (GR) and thioredoxin/thioredoxin reductase (TrxR) systems present in the host. Trypanothione synthetase (TryS) and TR are necessary for the protozoa survival. Consequently, enzymes involved in spermidine synthesis and its utilization, i.e. ARG, ODC, AdoMetDC, SpdS and, in particular, TryS and TR, are promising targets for drug development.
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Affiliation(s)
- Gianni Colotti
- Institute of Biology and Molecular Pathology, CNR, c/o Department of Biochemical Sciences, University Sapienza, P.le A. Moro 5, 00185, Rome, Italy.
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Bhattacharya A, Biswas A, Das PK. Role of a differentially expressed cAMP phosphodiesterase in regulating the induction of resistance against oxidative damage in Leishmania donovani. Free Radic Biol Med 2009; 47:1494-506. [PMID: 19733234 DOI: 10.1016/j.freeradbiomed.2009.08.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/04/2009] [Accepted: 08/20/2009] [Indexed: 11/20/2022]
Abstract
Differentiation-coupled induction of resistance of Leishmania parasites to macrophage oxidative damage was shown to be associated with an increased cAMP response. This study explores the significance of the cAMP response in the parasite by identifying a differentially expressed cAMP phosphodiesterase (LdPDEA) and deciphering its role in regulating antioxidant machineries in the parasite. LdPDEA, a high K(M) class I cytosolic cAMP phosphodiesterase, was expressed maximally in log-phase promastigotes, but was significantly reduced in stationary-phase promastigotes and amastigotes. Chemical inhibition or silencing of PDEA conferred enhanced resistance to pro-oxidants in these cells and this led to studies on trypanothione biosynthesis and utilization, as trypanothione is one of the major modulators of antioxidant defense in kinetoplastidae. Despite enhanced arginase and ornithine decarboxylase activity, trypanothione biosynthesis seemed to be unaffected by PDEA blockage, whereas significant elevations in the expression of tryparedoxin peroxidase, ascorbate peroxidase, and tryparedoxin were detected, suggesting a definite shift of trypanothione-pool utilization bias toward antioxidant defense. Moreover, parasites that overexpressed PDEA showed reduced resistance to oxidative damage and reduced infectivity toward activated macrophages. This study reveals the significance of a cAMP phosphodiesterase in the infectivity of Leishmania parasites.
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Affiliation(s)
- Arijit Bhattacharya
- Molecular Cell Biology Laboratory, Indian Institute of Chemical Biology, Kolkata 700032, India
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Leishmania donovani ornithine decarboxylase is indispensable for parasite survival in the mammalian host. Infect Immun 2008; 77:756-63. [PMID: 19064633 DOI: 10.1128/iai.01236-08] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mutations within the polyamine biosynthetic pathway of Leishmania donovani, the etiological agent of visceral leishmaniasis, confer polyamine auxotrophy to the insect vector or promastigote form of the parasite. However, whether the infectious or amastigote form of the parasite requires an intact polyamine pathway has remained an open question. To address this issue, conditionally lethal Deltaodc mutants lacking ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, were created by double targeted gene replacement within a virulent strain of L. donovani. ODC-deficient promastigotes and axenic amastigotes were auxotrophic for polyamines and capable of robust growth only when exogenous putrescine was supplied in the culture medium, confirming that polyamine biosynthesis is an essential nutritional pathway for L. donovani promastigotes. To assess whether the Deltaodc lesion also affected the ability of amastigotes to sustain a robust infection, macrophage and mouse infectivity experiments were performed. Parasite loads in murine macrophages infected with each of two independent Deltaodc knockout lines were decreased approximately 80% compared to their wild-type counterpart. Furthermore, alpha-difluoromethylornithine, a suicide inhibitor of ODC, inhibited growth of wild-type L. donovani amastigotes and effectively cured macrophages of parasites, thereby preventing host cell destruction. Strikingly, however, parasitemias of both Deltaodc null mutants were reduced by 6 and 3 orders of magnitude, respectively, in livers and spleens of BALB/c mice. The compromised infectivity phenotypes of the Deltaodc knockouts in both macrophages and mice were rescued by episomal complementation of the genetic lesion. These genetic and pharmacological studies strongly implicate ODC as an essential cellular determinant that is necessary for the viability and growth of both L. donovani promastigotes and amastigotes and intimate that pharmacological inhibition of ODC is a promising therapeutic paradigm for the treatment of visceral and perhaps other forms of leishmaniasis.
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Vannier-Santos MA, Menezes D, Oliveira MF, de Mello FG. The putrescine analogue 1,4-diamino-2-butanone affects polyamine synthesis, transport, ultrastructure and intracellular survival in Leishmania amazonensis. Microbiology (Reading) 2008; 154:3104-3111. [DOI: 10.1099/mic.0.2007/013896-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
| | - Diego Menezes
- Instituto Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Marcus F. Oliveira
- Instituto de Bioquímica Médica, Programa de Biologia Molecular e Biotecnologia, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil
| | - Fernando G. de Mello
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Dufe V, Ingner D, Heby O, Khomutov A, Persson L, Al-Karadaghi S. A structural insight into the inhibition of human and Leishmania donovani ornithine decarboxylases by 1-amino-oxy-3-aminopropane. Biochem J 2007; 405:261-8. [PMID: 17407445 PMCID: PMC1904517 DOI: 10.1042/bj20070188] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The critical role of polyamines in key processes such as cell growth, differentiation and macromolecular synthesis makes the enzymes involved in their synthesis potential targets in the treatment of certain types of cancer and parasitic diseases. Here we present a study on the inhibition of human and Leishmania donovani ODC (ornithine decarboxylase), the first committed enzyme in the polyamine biosynthesis pathway, by APA (1-amino-oxy-3-aminopropane). The present study shows APA to be a potent inhibitor of both human and L. donovani ODC with a K(i) value of around 1.0 nM. We also show that L. donovani ODC binds the substrate, the co-enzyme pyridoxal 5'-phosphate and the irreversible inhibitor alpha-difluoromethylornithine (a curative agent of West African sleeping sickness) with less affinity than human ODC. We have also determined the three-dimensional structure of human ODC in complex with APA, which revealed the mode of the inhibitor binding to the enzyme. In contrast with earlier reports, the structure showed no indication of oxime formation between APA and PLP (pyridoxal 5'-phosphate). Homology modelling suggests a similar mode of binding of APA to L. donovani ODC. A comparison of the ODC-APA-PLP structure with earlier ODC structures also shows that the protease-sensitive loop (residues 158-168) undergoes a large conformational change and covers the active site of the protein. The understanding of the structural mode of APA binding may constitute the basis for the development of more specific inhibitors of L. donovani ODC.
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Affiliation(s)
- Veronica T. Dufe
- *Department of Molecular Biophysics, Lund University, S-221 00 Lund, Sweden
| | - Daniel Ingner
- *Department of Molecular Biophysics, Lund University, S-221 00 Lund, Sweden
| | - Olle Heby
- †Department of Molecular Biology, Umeå University, S-901 87 Umeå, Sweden
| | - Alex R. Khomutov
- ‡Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Lo Persson
- §Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
- Correspondence may be addressed to either of these authors (email or )
| | - Salam Al-Karadaghi
- *Department of Molecular Biophysics, Lund University, S-221 00 Lund, Sweden
- Correspondence may be addressed to either of these authors (email or )
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Heby O, Persson L, Rentala M. Targeting the polyamine biosynthetic enzymes: a promising approach to therapy of African sleeping sickness, Chagas' disease, and leishmaniasis. Amino Acids 2007; 33:359-66. [PMID: 17610127 DOI: 10.1007/s00726-007-0537-9] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Accepted: 02/01/2007] [Indexed: 12/11/2022]
Abstract
Trypanosomatids depend on spermidine for growth and survival. Consequently, enzymes involved in spermidine synthesis and utilization, i.e. arginase, ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (AdoMetDC), spermidine synthase, trypanothione synthetase (TryS), and trypanothione reductase (TryR), are promising targets for drug development. The ODC inhibitor alpha-difluoromethylornithine (DFMO) is about to become a first-line drug against human late-stage gambiense sleeping sickness. Another ODC inhibitor, 3-aminooxy-1-aminopropane (APA), is considerably more effective than DFMO against Leishmania promastigotes and amastigotes multiplying in macrophages. AdoMetDC inhibitors can cure animals infected with isolates from patients with rhodesiense sleeping sickness and leishmaniasis, but have not been tested on humans. The antiparasitic effects of inhibitors of polyamine and trypanothione formation, reviewed here, emphasize the relevance of these enzymes as drug targets. By taking advantage of the differences in enzyme structure between parasite and host, it should be possible to design new drugs that can selectively kill the parasites.
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Affiliation(s)
- O Heby
- Department of Molecular Biology, Umeå University, Umeå, Sweden.
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Nasizadeh S, Thiman L, Persson L. Sequence elements essential for the rapid turnover of Crithidia fasciculata ornithine decarboxylase. Amino Acids 2007; 34:421-8. [PMID: 17514492 DOI: 10.1007/s00726-007-0552-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 03/30/2007] [Indexed: 11/25/2022]
Abstract
Ornithine decarboxylase (ODC) has a very fast turnover in mammalian cells, but is a stable enzyme in T. brucei and other trypanosmatid parasites like Leishmania donovani. However, Crithidia fasciculata, which is a phylogenetically closely related trypanosomatid to L. donovani, has an ODC with a rapid turnover. Interestingly, C. fasciculata ODC, but not L. donovani ODC, is rapidly degraded also in mammalian systems. In order to obtain information on what sequences are important for the rapid degradation of C. fasciculata ODC, we produced a variety of C. fasciculata/L. donovani ODC hybrid proteins and characterized their turnover using two different mammalian expression systems. The results obtained indicate that C. fasciculata ODC contains several sequence elements essential for the rapid turnover of the protein and that these regions are mainly located in the central part of the enzyme.
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Affiliation(s)
- S Nasizadeh
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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18
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Persson L. Ornithine decarboxylase and S-adenosylmethionine decarboxylase in trypanosomatids. Biochem Soc Trans 2007; 35:314-7. [PMID: 17371268 DOI: 10.1042/bst0350314] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The production of polyamines has been shown to be an effective target for a drug against the West African form of sleeping sickness caused by Trypanosoma brucei gambiense. T. brucei belongs to the group of protozoan parasites classed as trypanosomatids. Parasitic species of this group are the causative agents of various tropical diseases besides African sleeping sickness, e.g. Chagas' disease (Trypanosoma cruzi), cutaneous (Lesihmania spp.) and visceral (Leishmania donovani) leishmaniasis. The metabolism of polyamines in the parasites is a potential target for the development of new drugs for treatment of these diseases. The key steps in polyamine synthesis are catalysed by ODC (ornithine decarboxylase) and AdoMetDC (S-adenosylmethionine decarboxylase). In the present paper, some of the available information on ODC and AdoMetDC in trypanosomatids will be described and discussed.
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Affiliation(s)
- L Persson
- Department of Experimental Medical Science, Lund University, BMC F:13, S-221 84 Lund, Sweden.
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19
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Roberts SC, Jiang Y, Gasteier J, Frydman B, Marton LJ, Heby O, Ullman B. Leishmania donovani polyamine biosynthetic enzyme overproducers as tools to investigate the mode of action of cytotoxic polyamine analogs. Antimicrob Agents Chemother 2006; 51:438-45. [PMID: 17116678 PMCID: PMC1797743 DOI: 10.1128/aac.01193-06] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A number of anticancer and antiparasitic drugs are postulated to target the polyamine biosynthetic pathway and polyamine function, but the exact mode of action of these compounds is still being elucidated. To establish whether polyamine analogs specifically target enzymes of the polyamine pathway, a model was developed using strains of the protozoan parasite Leishmania donovani that overproduce each of the polyamine biosynthetic enzymes. Promastigotes overexpressing episomal constructs encoding ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (ADOMETDC), or spermidine synthase (SPDSYN) revealed robust overproduction of the corresponding polyamine biosynthetic enzyme. Polyamine pools, however, were either unchanged or only marginally affected, implying that regulatory mechanisms must exist. The ODC, ADOMETDC, and SPDSYN overproducer strains exhibited a high level of resistance to difluoromethylornithine, 5'-{[(Z)-4-amino-2-butenyl]methylamino}-5'-deoxyadenosine, and n-butylamine, respectively, confirming previous observations that these agents specifically target polyamine enzymes. Conversely, augmented levels of polyamine biosynthetic enzymes did not affect the sensitivity of L. donovani promastigotes to pentamidine, berenil, and mitoguazone, drugs that were postulated to target the polyamine pathway, implying alternative and/or additional targets for these agents. The sensitivities of wild-type and overproducing parasites to a variety of polyamine analogs were also tested. The polyamine enzyme-overproducing lines offer a rapid cell-based screen for assessing whether synthetic polyamine analogs exert their mechanism of action predominantly on the polyamine biosynthetic pathway in L. donovani. Furthermore, the drug resistance engendered by the amplification of target genes and the overproduction of the encoded protein offers a general strategy for evaluating and developing therapeutic agents that target specific proteins in Leishmania.
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Affiliation(s)
- Sigrid C Roberts
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, OR 97239-3098, USA
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20
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Singh S, Mukherjee A, Khomutov AR, Persson L, Heby O, Chatterjee M, Madhubala R. Antileishmanial effect of 3-aminooxy-1-aminopropane is due to polyamine depletion. Antimicrob Agents Chemother 2006; 51:528-34. [PMID: 17101681 PMCID: PMC1797741 DOI: 10.1128/aac.01055-06] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The polyamines putrescine, spermidine, and spermine are organic cations that are required for cell growth and differentiation. Ornithine decarboxylase (ODC), the first and rate-limiting enzyme in the polyamine biosynthetic pathway, catalyzes the conversion of ornithine to putrescine. As the polyamine biosynthetic pathway is essential for the growth and survival of Leishmania donovani, the causative agent of visceral leishmaniasis, inhibition of the pathway is an important leishmaniacidal strategy. In the present study, we examined for the first time the effects of 3-aminooxy-1-aminopropane (APA), an ODC inhibitor, on the growth of L. donovani. APA inhibited the growth of both promastigotes in vitro and amastigotes in the macrophage model, with the 50% inhibitory concentrations being 42 and 5 microM, respectively. However, concentrations of APA up to 200 microM did not affect the viability of macrophages. The effects of APA were completely abolished by the addition of putrescine or spermidine. APA induced a significant decrease in ODC activity and putrescine, spermidine, and trypanothione levels in L. donovani promastigotes. Parasites were transfected with an episomal ODC construct, and these ODC overexpressers exhibited significant resistance to APA and were concomitantly resistant to sodium antimony gluconate (Pentostam), indicating a role for ODC overexpression in antimonial drug resistance. Clinical isolates with sodium antimony gluconate resistance were also found to overexpress ODC and to have significant increases in putrescine and spermidine levels. However, no increase in trypanothione levels was observed. The ODC overexpression in these clinical isolates alleviated the antiproliferative effects of APA. Collectively, our results demonstrate that APA is a potent inhibitor of L. donovani growth and that its leishmaniacidal effect is due to inhibition of ODC.
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Affiliation(s)
- Sushma Singh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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21
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Steglich C, Schaeffer SW. The ornithine decarboxylase gene of Trypanosoma brucei: Evidence for horizontal gene transfer from a vertebrate source. INFECTION GENETICS AND EVOLUTION 2005; 6:205-19. [PMID: 16344004 DOI: 10.1016/j.meegid.2005.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Revised: 05/20/2005] [Accepted: 05/25/2005] [Indexed: 11/29/2022]
Abstract
Kinetoplastid protozoans in the family Trypanosomatidae are parasites, many of them responsible for serious diseases in humans and domestic animals. Ornithine decarboxlyase (ODC), a protein at the core of polyamine metabolism, is a potential target for therapies to overcome these diseases. Eukaryotic phylogenies were constructed from full-length genes for ODC to determine the origin of ODC in the kinetoplastid protozoans. The Odc genes from Trypanosoma brucei and two other African trypanosomes, T. congolense and T. vivax, clustered with Odc genes from vertebrates rather than with Odc genes from other kinetoplastids and other protozoans, making this gene a candidate for horizontal gene transfer from a vertebrate source. This result is unique to the Odc gene from the African trypanosomes as four other genes produced phylogenies consistent with the expected taxonomic relationships for the organisms. Analysis of the genomic regions around the Odc genes in Leishmania major, T. brucei, and Trypanosoma cruzi supports the hypothesis of loss of the Odc gene in the Trypanosoma lineage followed by acquisition of a new copy from a vertebrate host in the African branch of the genus.
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Affiliation(s)
- Carolyn Steglich
- Department of Biology, Slippery Rock University, Slippery Rock, PA 16057, USA.
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22
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Nasizadeh S, Myhre L, Thiman L, Alm K, Oredsson S, Persson L. Importance of polyamines in cell cycle kinetics as studied in a transgenic system. Exp Cell Res 2005; 308:254-64. [PMID: 15923003 DOI: 10.1016/j.yexcr.2005.04.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 04/22/2005] [Accepted: 04/26/2005] [Indexed: 11/19/2022]
Abstract
Polyamines are organic cations, which are considered essential for normal cell cycle progression. This view is based on results from numerous studies using a variety of enzyme inhibitors or polyamine analogues interfering with either the metabolism or the physiological functions of the polyamines. However, the presence of non-specific effects may be hard to rule out in such studies. In the present study, we have for the first time used a transgenic cell system to analyze the importance of polyamines in cell growth. We have earlier shown that expression of trypanosomal ODC in an ODC-deficient variant of CHO cells (C55.7) supported growth of these otherwise polyamine auxotrophic cells. However, one of the transgenic cell lines grew much slower than the others. As shown in the present study, the level of ODC activity was much lower in these cells, and that was reflected in a reduction of cellular polyamine levels. Analysis of cell cycle kinetics revealed that reduction of growth was correlated to prolongation of the G1, S, and G2+M phases in the cells. Providing exogenous putrescine to the cells resulted in a normalization of polyamine levels as well as cell cycle kinetics indicating a causal relationship.
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Affiliation(s)
- Sima Nasizadeh
- Department of Physiological Sciences, Lund University, BMC F-13, S-221 84 Lund, Sweden
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23
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Abstract
The emergence of drug resistance in protozoan parasites is a major obstacle to their control. Since vaccines are not yet in sight for several of these parasites, there is on urgent need to develop new and better drugs. These antimicrobial agents will possibly be more expensive, and will therefore impose on additional burden in health-care costs and in the planning of public health policies of the developing countries. A better understanding of drug resistance, to try to circumvent or overcome it, and the search for new specific cellular targets of parasites are warranted. The development, in vitro, of drug-resistant parasite cell lines has been instrumental in our understanding of the mechanisms of drug resistance in parasitic protozoans. Marc Ouellette and Barbara Popodopoulou here present on overview of the recent progress on the elucidation of mechanisms of drug resistance in the protozoan parasite Leishmania, selected under laboratory conditions.
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Affiliation(s)
- M Ouellette
- Service d'Infectiologie du Centre de Recherche du CHUL, 2705 Boulevard Laurier, Sointe-Fay, Québec, Canada GIV 4G2
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24
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Abstract
The genome of Leishmania is quite plastic. Chromosomal rearrangements and DNA amplifications are common events in all the species of the genus. Gene amplification occurs both as a mechanism of drug resistance and in the absence of drug pressure. The best known spontaneous amplification in Leishmania is the so-called LD1 family of amplicons. In the past few years there have been great advances in our knowledge of LD1 elements; here, Manuel Segovia and Ginés Ortiz review all the available data.
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Affiliation(s)
- M Segovia
- Departamento de Genética y Microbiología, Facultad de Medicina, Universidad de Murcia, Spain.
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25
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Reguera RM, Tekwani BL, Balaña-Fouce R. Polyamine transport in parasites: a potential target for new antiparasitic drug development. Comp Biochem Physiol C Toxicol Pharmacol 2005; 140:151-64. [PMID: 15907761 DOI: 10.1016/j.cca.2005.02.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2004] [Revised: 02/07/2005] [Accepted: 02/08/2005] [Indexed: 10/25/2022]
Abstract
The metabolism of the naturally occurring polyamines-putrescine, spermidine and spermine-is a highly integrated system involving biosynthesis, uptake, degradation and interconversion. Metabolic differences in polyamine metabolism have long been considered to be a potential target to arrest proliferative processes ranging from cancer to microbial and parasitic diseases. Despite the early success of polyamine inhibitors such as alpha-difluoromethylornithine (DFMO) in treating the latter stages of African sleeping sickness, in which the central nervous system is affected, they proved to be ineffective in checking other major diseases caused by parasitic protozoa, such as Chagas' disease, leishmaniasis or malaria. In the use and design of new polyamine-based inhibitors, account must be taken of the presence of up-regulated polyamine transporters in the plasma membrane of the infectious agent that are able to circumvent the effect of the drug by providing the parasite with polyamines from the host. This review contains information on the polyamine requirements and molecular, biochemical and genetic characterization of different transport mechanisms in the parasitic agents responsible for a number of the deadly diseases that afflict underdeveloped and developing countries.
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Affiliation(s)
- Rosa María Reguera
- Department of Pharmacology and Toxicology (INTOXCAL), University of Leon, Campus de Vegazana (s/n) 24071 Leon, Spain
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26
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Roberts SC, Tancer MJ, Polinsky MR, Gibson KM, Heby O, Ullman B. Arginase plays a pivotal role in polyamine precursor metabolism in Leishmania. Characterization of gene deletion mutants. J Biol Chem 2004; 279:23668-78. [PMID: 15023992 DOI: 10.1074/jbc.m402042200] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The polyamine pathway of protozoan parasites has been successfully targeted in anti-parasitic therapies and is significantly different from that of the mammalian host. To gain knowledge into the metabolic routes by which parasites synthesize polyamines and their precursors, the arginase gene was cloned from Leishmania mexicana, and Deltaarg null mutants were created by double targeted gene replacement and characterized. The ARG sequence exhibited significant homology to ARG proteins from other organisms and predicted a peroxisomal targeting signal (PTS-1) that steers proteins to the glycosome, an organelle unique to Leishmania and related parasites. ARG was subsequently demonstrated to be present in the glycosome, whereas the polyamine biosynthetic enzymes, in contrast, were shown to be cytosolic. The Deltaarg knockouts expressed no ARG activity, lacked an intracellular ornithine pool, and were auxotrophic for ornithine or polyamines. The ability of the Deltaarg null mutants to proliferate could be restored by pharmacological supplementation, either with low putrescine or high ornithine or spermidine concentrations, or by complementation with an arginase episome. Transfection of an arg construct lacking the PTS-1 directed the synthesis of an arg that mislocalized to the cytosol and notably also complemented the genetic lesion and restored polyamine prototrophy to the Deltaarg parasites. This molecular, biochemical, and genetic dissection of ARG function in L. mexicana promastigotes establishes: (i) that the enzyme is essential for parasite viability; (ii) that Leishmania, unlike mammalian cells, expresses only one ARG activity; (iii) that the sole vital function of ARG is to provide polyamine precursors for the parasite; and (iv) that ARG is present in the glycosome, but this subcellular milieu is not essential for its role in polyamine biosynthesis.
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Affiliation(s)
- Sigrid C Roberts
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland 97239-3098, USA
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27
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Nasizadeh S, Persson L. Extremely rapid turnover of S-adenosylmethionine decarboxylase inCrithidia fasciculata. FEBS Lett 2003; 553:131-4. [PMID: 14550560 DOI: 10.1016/s0014-5793(03)00986-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The activity of S-adenosylmethionine decarboxylase (AdoMetDC) in Crithidia fasciculata was shown to be correlated to the growth of the parasite. An increase in activity was observed during exponential growth. Inhibition of protein synthesis induced an extremely rapid decay of AdoMetDC activity. The half-life of the enzyme was estimated to be about 3 min, which is the shortest half-life ever recorded for an eukaryotic AdoMetDC. The reduction in AdoMetDC activity was correlated with a decrease in AdoMetDC protein content, demonstrating a rapid turnover of the enzyme. No polyamine-mediated feedback regulation of AdoMetDC was observed in the parasite.
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Affiliation(s)
- Sima Nasizadeh
- Department of Physiological Sciences, Lund University, Sweden
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28
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Kaiser AE, Gottwald AM, Wiersch CS, Maier WA, Seitz HM. Spermidine metabolism in parasitic protozoa--a comparison to the situation in prokaryotes, viruses, plants and fungi. Folia Parasitol (Praha) 2003; 50:3-18. [PMID: 12735718 DOI: 10.14411/fp.2003.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Targeting polyamines of parasitic protozoa in chemotherapy has attracted attention because polyamines might reveal novel drug targets for antiparasite therapies (Müller et al. 2001). The biological function of the triamine spermidine in parasitic protozoa has not been studied in great detail although the results obtained mainly imply three different functions, i.e., cell proliferation, cell differentiation, and biosynthesis of macromolecules. Sequence information from the malaria genome project databases and inhibitor studies provide evidence that the current status of spermidine research has to be extended since enzymes of spermidine metabolism are present in the parasite (Kaiser et al. 2001). Isolation and characterisation of these enzymes, i.e., deoxyhypusine synthase (EC 1.1.1.249) (DHS) and homospermidine synthase (EC 2.5.1.44) (HSS) might lead to valuable new targets in drug therapy. Currently research on spermidine metabolism is based on the deposition of the deoxyhypusine synthase nucleic acid sequence in GenBank while the activity of homospermidine synthase was deduced from inhibitor studies. Spermidine biosynthesis is catalyzed by spermidine synthase (EC 2.5.1.16) which transfers an aminopropyl moiety from decarboxylated S-adenosylmethionine to putrescine. Spermidine is also an important precursor in the biosynthesis of the unusual amino acid hypusine (Wolff et al. 1995) and the uncommon triamine homospermidine in eukaryotes, in particular in pyrrolizidine alkaloid-producing plants (Ober and Hartmann 2000). Hypusine is formed by a two-step enzymatic mechanism starting with the transfer of an aminobutyl moiety from spermidine to the epsilon-amino group of one of the lysine residues in the precursor protein of eukaryotic initiation factor eIF5A by DHS (Lee and Park 2000). The second step of hypusinylation is completed by deoxyhypusine hydroxylase (EC 1.14.9929) (Abbruzzese et al. 1985). Homospermidine formation in eukaryotes parallels deoxyhypusine formation in the way that in an NAD(+)-dependent reaction an aminobutyl moiety is transferred from spermidine. In the case of homospermidine synthase, however the acceptor is putrescine. Thus the triamine homospermidine consists of two symmetric aminobutyl moieties while there is one aminobutyl and one aminopropyl moiety present in spermidine. Here, we review the metabolism of the triamine spermidine with particular focus on the biosynthesis of hypusine and homospermidine in parasitic protozoa, i.e., Plasmodium, Trypanosoma and Leishmania, compared to that in prokaryotes i.e., Escherichia coli, a phytopathogenic virus and pyrrolizidine alkaloid-producing plants (Asteraceae) and fungi.
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Affiliation(s)
- Annette E Kaiser
- Institut für Medizinische Parasitologie, Rheinische-Friedrich-Wilhelms-Universität Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
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29
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Abstract
Current treatments for the parasitic disease leishmaniasis are unsatisfactory due to their route of administration, toxicity and expense. Resistance is also developing to first-line antimonial drugs. Fortunately, a handful of antileishmanial agents, such as the orally available compound miltefosine, are currently in clinical trials. In addition, several promising drug targets and lead molecules are being studied with the goal of developing new antileishmanial agents. Drug candidates have been identified through the continued investigation of parasite sterol metabolism and parasite proteases. New antileishmanial molecules have also been discovered through the study of novel targets and pathways, such as the bisphosphonate inhibitors of isoprenoid biosynthesis. This review presents a synopsis of the drug targets and lead compounds that have been investigated over the last few years against leishmaniasis, gives a perspective on the chemotherapeutic potential of each and discusses some of the obstacles to antileishmanial drug development.
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Affiliation(s)
- Karl A Werbovetz
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Ohio State University, 500 West 12th Avenue, Columbus, OH 43210, USA.
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30
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Roberts SC, Scott J, Gasteier JE, Jiang Y, Brooks B, Jardim A, Carter NS, Heby O, Ullman B. S-adenosylmethionine decarboxylase from Leishmania donovani. Molecular, genetic, and biochemical characterization of null mutants and overproducers. J Biol Chem 2002; 277:5902-9. [PMID: 11734561 DOI: 10.1074/jbc.m110118200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The polyamine biosynthetic enzyme, S-adenosylmethionine decarboxylase (ADOMETDC) has been advanced as a potential target for antiparasitic chemotherapy. To investigate the importance of this protein in a model parasite, the gene encoding ADOMETDC has been cloned and sequenced from Leishmania donovani. The Delta adometdc null mutants were created in the insect vector form of the parasite by double targeted gene replacement. The Delta adometdc strains were incapable of growth in medium without polyamines; however, auxotrophy could be rescued by spermidine but not by putrescine, spermine, or methylthioadenosine. Incubation of Delta adometdc parasites in medium lacking polyamines resulted in a drastic increase of putrescine and glutathione levels with a concomitant decrease in the amounts of spermidine and the spermidine-containing thiol trypanothione. Parasites transfected with an episomal ADOMETDC construct were created in both wild type and Delta adometdc parasites. ADOMETDC overexpression abrogated polyamine auxotrophy in the Delta adometdc L. donovani. In addition, ADOMETDC overproduction in wild type parasites alleviated the toxic effects of 5'-(((Z)-4-amino-2-butenyl)methylamino)-5'-deoxyadenosine (MDL 73811), but not pentamidine, berenil, or methylglyoxyl bis(guanylhydrazone), all inhibitors of ADOMETDC activities in vitro. The molecular, biochemical, and genetic characterization of ADOMETDC establishes that it is essential in L. donovani promastigotes and a potential target for therapeutic validation.
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Affiliation(s)
- Sigrid C Roberts
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97201-3098, USA
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31
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Dutta M, Delhi P, Sinha KM, Banerjee R, Datta AK. Lack of abundance of cytoplasmic cyclosporin A-binding protein renders free-living Leishmania donovani resistant to cyclosporin A. J Biol Chem 2001; 276:19294-300. [PMID: 11278494 DOI: 10.1074/jbc.m009379200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The majority of the effects of cyclosporin A (CsA) on cells is caused by the inhibition of phosphatase activity of calcineurin (CN) by the cyclophilin A (CyPA)-CsA complex formed in the cytoplasm. Although CsA inhibits the proliferation of a large number of parasites, not all are susceptible. The presence of structurally altered CyPA with lower affinity for CsA had been suggested to be the cause of resistance. We report here the identification and cloning of a high affinity CsA-binding protein (LdCyP) from Leishmania donovani, a trypanosomatid parasite that is naturally resistant to CsA. The translated LdCyP consists of 187 amino acids with a cleavable 21-amino acid hydrophobic NH(2)-terminal extension. Modeling studies confirmed that all the residues of human CyPs responsible for interaction with CsA are sequentially and conformationally conserved in LdCyP. The purified recombinant protein displayed biochemical parameters comparable to human CyPs. Reverse transcription-polymerase chain reaction analysis confirmed that LdCyP was abundantly expressed. Immunoblot experiments and direct CsA binding studies revealed that LdCyP located in the subcellular organelles constituted the bulk of the CsA binding activity present in L. donovani, whereas the level of binding activity in the cytosol was conspicuously low. CsA selectively facilitated the secretion of LdCyP in the culture medium. Based on these results, it is concluded that the insensitivity of L. donovani to CsA is probably due to the paucity of CsA binding activity in the cytoplasm of the parasite. We suggest that LdCyP, located in the secretory pathway, may function as a chaperone by binding to membrane proteins rather than as the mediator of CN inhibition.
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Affiliation(s)
- M Dutta
- Leishmania Group, Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Rd., Kolkata 700 032, India
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32
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Abstract
All parasitic protozoa contain polyamines and in recent years they, and their associated enzymes, have attracted attention as drug targets because they might reveal novel antiparasite therapies. How justified is this approach to drug discovery? In this review, Sylke Müller, Graham Coombs and Rolf Walter summarize the current status of research into drugs that exploit polyamine metabolism of trypanosomatid and malaria parasites, and propose priorities for research into such drugs. This review was inspired by an Expert Meeting entitled 'Polyamine Metabolism of Parasitic Protozoa as a Drug Target'.
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Affiliation(s)
- S Müller
- Wellcome Trust Biocentre, University of Dundee, DD1 5EH, UK
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33
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Mastri C, Thorborn DE, Davies AJ, Ariyanayagam MR, Hunter KJ. Polyamine and thiol metabolism in Trypanosoma granulosum: similarities with Trypanosoma cruzi. Biochem Biophys Res Commun 2001; 282:1177-82. [PMID: 11302739 DOI: 10.1006/bbrc.2001.4704] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Concentrations of free polyamines were investigated in Trypanosoma granulosum cultured in a semidefined medium containing traces of polyamines. Spermidine content peaked in early logarithmic growth while putrescine was not detectable. Unlike African trypanosomes and Leishmania, spermine was measured at equivalent amounts to spermidine in mid to late logarithmic stage cells. Addition of d,l-alpha-difluoromethylornithine to cultures did not decrease polyamine content nor was ornithine decarboxylase activity detected. In contrast, incubation of parasites with tritiated putrescine showed rapid uptake and subsequent conversion to spermidine and spermine. At late logarithmic growth, parasites contained glutathione (77% of total sulphydryl groups) and ovothiol A as major low molecular mass thiols with glutathionylpolyamine conjugates undetectable. However, the addition of exogenous putrescine elevated trypanothione and glutathionylspermidine content to 48% of total sulphydryl groups. Correspondingly, the addition of exogenous cadaverine increased homotrypanothione content. This first report of polyamines and low molecular mass thiols in Trypanosoma granulosum indicates intriguing similarities with the metabolism of the human pathogen Trypanosoma cruzi.
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Affiliation(s)
- C Mastri
- School of Life Sciences, University of Kingston, Kingston upon Thames, KT1 2EE, United Kingdom.
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Carrillo C, Cejas S, Cortés M, Ceriani C, Huber A, González NS, Algranati ID. Sensitivity of trypanosomatid protozoa to DFMO and metabolic turnover of ornithine decarboxylase. Biochem Biophys Res Commun 2000; 279:663-8. [PMID: 11118342 DOI: 10.1006/bbrc.2000.3996] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
alpha-Difluoromethylornithine (DFMO), the specific and irreversible inhibitor of ornithine decarboxylase (ODC), was able to induce the arrest of proliferation in Leishmania mexicana and ODC-transformed Trypanosoma cruzi cultures grown in a semi-defined medium essentially free of polyamines. Conversely, Crithidia fasciculata and Phytomonas 274 were not affected by the inhibitor. The drug-resistance of Crithidia and Phytomonas was neither caused by an impairment of DFMO uptake nor by a decrease of the enzyme affinity for the inhibitor. We were also able to rule out the possibility of ODC overexpression in the drug-tolerant parasites. The measurements of ODC metabolic turnover indicated that the enzymes from Crithidia and Phytomonas have a short half-life of 20-40 min, while ODC from Leishmania and transgenic Trypanosoma cruzi are rather stable with a half-life longer than 6 hours. Analyses of polyamine internal pools under different growth conditions have shown that DFMO was able to markedly decrease the levels of putrescine and spermidine in all parasites, but the depletion of spermidine was higher in trypanosomatids containing an ODC with slow turnover. Our results suggest that in these parasites cultivated in the presence of the drug, spermidine might decrease below critical levels needed to maintain trypanothione concentrations or other conditions essential for normal proliferation.
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Affiliation(s)
- C Carrillo
- Instituto de Investigaciones Bioquímicas "Fundación Campomar,", Facultad de Ciencias Exactas y Naturales, A. Machado 151, Buenos Aires, 1405, Argentina
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Miller MA, McGowan SE, Gantt KR, Champion M, Novick SL, Andersen KA, Bacchi CJ, Yarlett N, Britigan BE, Wilson ME. Inducible resistance to oxidant stress in the protozoan Leishmania chagasi. J Biol Chem 2000; 275:33883-9. [PMID: 10931831 DOI: 10.1074/jbc.m003671200] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leishmania sp. protozoa are introduced into a mammalian skin by a sandfly vector, whereupon they encounter increased temperature and toxic oxidants generated during phagocytosis. We studied the effects of 37 degrees C "heat shock" or sublethal menadione, which generates superoxide and hydrogen peroxide, on Leishmania chagasi virulence. Both heat and menadione caused parasites to become more resistant to H(2)O(2)-mediated toxicity. Peroxide resistance was also induced as promastigotes developed in culture from logarithmic to their virulent stationary phase form. Peroxide resistance was not associated with an increase in reduced thiols (trypanothione and glutathione) or increased activity of ornithine decarboxylase, which is rate-limiting in trypanothione synthesis. Membrane lipophosphoglycan increased in size as parasites developed to stationary phase but not after environmental exposures. Instead, parasites underwent a heat shock response upon exposure to heat or sublethal menadione, detected by increased levels of HSP70. Transfection of promastigotes with L. chagasi HSP70 caused a heat-inducible increase in resistance to peroxide, implying it is involved in antioxidant defense. We conclude that leishmania have redundant mechanisms for resisting toxic oxidants. Some are induced during developmental change and others are induced in response to environmental stress.
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Affiliation(s)
- M A Miller
- Veterans Affairs Medical Center, the Departments of Internal Medicine and Microbiology, and the Interdisciplinary Immunology Program, University of Iowa, Iowa City, Iowa 52242, USA
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36
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Jardim A, Liu W, Zheleznova E, Ullman B. Peroxisomal targeting signal-1 receptor protein PEX5 from Leishmania donovani. Molecular, biochemical, and immunocytochemical characterization. J Biol Chem 2000; 275:13637-44. [PMID: 10788481 DOI: 10.1074/jbc.275.18.13637] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human pathogens of the Leishmania and Trypanosoma genera compartmentalize glycolytic and other key metabolic pathways in unique subcellular microbodies called glycosomes, organelles related to the peroxisomes of mammals and yeast. The molecular machinery that carries out the specific targeting of glycosomal proteins to the organelle has not been characterized, although the bulk of glycosomal proteins contain the COOH-terminal tripeptide glycosomal peroxisomal targeting signal-1 (PTS-1) similar to the mammalian and fungal peroxisomal targeting signal. To characterize the mechanisms of glycosomal targeting, the gene encoding PEX5, designated LdPEX5, has been isolated from Leishmania donovani. LdPEX5 encodes a 625-amino acid protein with a molecular mass of 69.7 kDa. Like its homologs in yeast and humans, LdPEX5 predicts a protein with seven copies of a tetratricopeptide repeat in its COOH-terminal half proposed to mediate PTS-1 binding and three copies of a WXXX(Y/F) motif in its NH(2) terminus conjectured to be essential for protein translocation into the organelle. LdPEX5 was overexpressed in Escherichia coli and purified to homogeneity for binding experiments and generation of antibodies. Recombinant LdPEX5 bound xanthine phosphoribosyltransferase (XPRT), a PTS-1 containing glycosomal protein with a K(D) of 4.2 nm, but did not bind an XPRT in which the PTS-1 had been deleted. Moreover, binding studies with the COOH-terminal half of the LdPEX5 confirmed that this portion of the PEX5 protein was capable of binding the XPRT PTS-1 with an affinity of 17.3 nm. Confocal microsocopy revealed that LdPEX5 was predominantly in the cytosolic milieu, and genetic analysis implied that LdPEX5 was an essential gene.
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Affiliation(s)
- A Jardim
- Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland, Oregon 97201, USA
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37
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Müller S, Da'dara A, Lüersen K, Wrenger C, Das Gupta R, Madhubala R, Walter RD. In the human malaria parasite Plasmodium falciparum, polyamines are synthesized by a bifunctional ornithine decarboxylase, S-adenosylmethionine decarboxylase. J Biol Chem 2000; 275:8097-102. [PMID: 10713131 DOI: 10.1074/jbc.275.11.8097] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The polyamines putrescine, spermidine, and spermine are crucial for cell differentiation and proliferation. Interference with polyamine biosynthesis by inhibition of the rate-limiting enzymes ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) has been discussed as a potential chemotherapy of cancer and parasitic infections. Usually both enzymes are individually transcribed and highly regulated as monofunctional proteins. We have isolated a cDNA from the malaria parasite Plasmodium falciparum that encodes both proteins on a single open reading frame, with the AdoMetDC domain in the N-terminal region connected to a C-terminal ODC domain by a hinge region. The predicted molecular mass of the entire transcript is 166 kDa. The ODC/AdoMetDC coding region was subcloned into the expression vector pASK IBA3 and transformed into the AdoMetDC- and ODC-deficient Escherichia coli cell line EWH331. The resulting recombinant protein exhibited both AdoMetDC and ODC activity and co-eluted after gel filtration on Superdex S-200 at approximately 333 kDa, which is in good agreement with the molecular mass of approximately 326 kDa determined for the native protein from isolated P. falciparum. SDS-polyacrylamide gel electrophoresis analysis of the recombinant ODC/AdoMetDC revealed a heterotetrameric structure of the active enzyme indicating processing of the AdoMetDC domain. The data presented describe the occurrence of a unique bifunctional ODC/AdoMetDC in P. falciparum, an organization which is possibly exploitable for the design of new antimalarial drugs.
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Affiliation(s)
- S Müller
- Bernhard Nocht Institute for Tropical Medicine, Biochemical Parasitology, Bernhard-Nocht-Str. 74, D-20359 Hamburg, Germany
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38
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Haimeur A, Guimond C, Pilote S, Mukhopadhyay R, Rosen BP, Poulin R, Ouellette M. Elevated levels of polyamines and trypanothione resulting from overexpression of the ornithine decarboxylase gene in arsenite-resistant Leishmania. Mol Microbiol 1999; 34:726-35. [PMID: 10564512 DOI: 10.1046/j.1365-2958.1999.01634.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The levels of trypanothione, a glutathione-spermidine conjugate, are increased in the protozoan parasite Leishmania selected for resistance to the heavy metal arsenite. The levels of putrescine and spermidine were increased in resistant mutants. This increase is mediated by overexpression of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis. Gene overexpression is generally mediated by gene amplification in Leishmania but, here, the mRNA and the enzymatic activity of ODC are increased without gene amplification. This RNA overexpression is stable when cells are grown in the absence of the drug and does not result from gene rearrangements or from an increased rate of RNA synthesis. Transient transfections suggest that mutations in the revertant cells contribute to these elevated levels of RNA. Stable transfection of the ODC gene increases the level of trypanothione, which can contribute to arsenite resistance. In addition to ODC overexpression, the gene for the ABC transporter PGPA is amplified in the mutants. The co-transfection of the ODC and PGPA genes confers resistance in a synergistic fashion in partial revertants, also suggesting that PGPA recognizes metals conjugated to trypanothione.
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Affiliation(s)
- A Haimeur
- Centre de Recherche en Infectiologie, Université Laval, Québec, Canada
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39
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Carrillo C, Cejas S, González NS, Algranati ID. Trypanosoma cruzi epimastigotes lack ornithine decarboxylase but can express a foreign gene encoding this enzyme. FEBS Lett 1999; 454:192-6. [PMID: 10431805 DOI: 10.1016/s0014-5793(99)00804-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Trypanosoma cruzi, a pathogenic protozoan causing Chagas disease, lacks ornithine decarboxylase (ODC), the enzyme catalyzing the first step of polyamine biosynthetic pathway in eukaryotic cells. Our results indicate that the auxotrophy for diamines of T. cruzi epimastigotes is due to the absence of an active ODC gene in these parasites and not to the inability for the expression of this gene. The introduction of an exogenous complete coding region from Crithidia fasciculata ODC gene inserted in an expression vector specific for trypanosomatids induces the normal expression of the foreign genetic information allowing the transformed T. cruzi to overcome the exogenous polyamine requirement for growth. The enzyme expressed in the transformed parasites has shown a considerably extended metabolic stability. The loss of ODC activity in T. cruzi might be related to the parasite adaptation to the intracellular stages of its life cycle.
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Affiliation(s)
- C Carrillo
- Instituto de Investigaciones Bioquímicas Fundación Campomar, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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40
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Jiang Y, Roberts SC, Jardim A, Carter NS, Shih S, Ariyanayagam M, Fairlamb AH, Ullman B. Ornithine decarboxylase gene deletion mutants of Leishmania donovani. J Biol Chem 1999; 274:3781-8. [PMID: 9920931 DOI: 10.1074/jbc.274.6.3781] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A knockout strain of Leishmania donovani lacking both ornithine decarboxylase (ODC) alleles has been created by targeted gene replacement. Growth of Deltaodc cells in polyamine-deficient medium resulted in a rapid and profound depletion of cellular putrescine pools, although levels of spermidine were relatively unaffected. Concentrations of trypanothione, a spermidine conjugate, were also reduced, whereas glutathione concentrations were augmented. The Deltaodc L. donovani exhibited an auxotrophy for polyamines that could be circumvented by the addition of the naturally occurring polyamines, putrescine or spermidine, to the culture medium. Whereas putrescine supplementation restored intracellular pools of both putrescine and spermidine, exogenous spermidine was not converted back to putrescine, indicating that spermidine alone is sufficient to meet the polyamine requirement, and that L. donovani does not express the enzymatic machinery for polyamine degradation. The lack of a polyamine catabolic pathway in intact parasites was confirmed radiometrically. In addition, the Deltaodc strain could grow in medium supplemented with either 1,3-diaminopropane or 1, 5-diaminopentane (cadaverine), but polyamine auxotrophy could not be overcome by other aliphatic diamines or spermine. These data establish genetically that ODC is an essential gene in L. donovani, define the polyamine requirements of the parasite, and reveal the absence of a polyamine-degradative pathway.
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Affiliation(s)
- Y Jiang
- Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA
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41
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Arana FE, Pérez-Victoria JM, Repetto Y, Morello A, Castanys S, Gamarro F. Involvement of thiol metabolism in resistance to glucantime in Leishmania tropica. Biochem Pharmacol 1998; 56:1201-8. [PMID: 9802332 DOI: 10.1016/s0006-2952(98)00129-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Clinical resistance to pentavalent antimonials, in the form of pentostam (sodium stibogluconate) or glucantime (N-methylglucamine antimoniate), has long been recognized as a problem in Leishmaniasis. However, the mechanisms of resistance are unclear. We selected in vitro a Leishmania tropica line resistant to 1.2 mg/mL of Sb(V) of glucantime (GLU-R10). The cell line has a stable phenotype for at least 6 months and a resistance index of 1400-fold. The resistant line has no cross-resistance to pentostam or to SbCl3 and SbCl5. The resistance to glucantime was reverted by buthionine sulfoximine (BSO) and chlorambucil (CLB); however, thiol analyses by HPLC of wild-type and GLU-R10 cell lines, in the presence or absence of the drug, showed no differences between these two cell lines. The resistant line had a DNA amplification shown as a circular extrachromosomal element (G-circle) of approximately 22 kb. However, the specific probes for gamma-glutamyl cysteine synthetase, ornithine decarboxylase and trypanothione reductase did not recognize the G-circle amplified in the GLU-R10. The G-circle did not arise from the H region and was not related with P-glycoprotein Pgp-MDR- or Pgp-MRP-like genes. Northern blot analysis of the G-circle showed that a single transcript of approximately 6 kb was overexpressed in the resistant line. Molecular characterization of the G-circle would lead to the determination of the gene(s) involved in resistance to glucantime in Leishmania.
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Affiliation(s)
- F E Arana
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Granada, Spain
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42
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Abstract
To dissect the contributions of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), adenine phosphoribosyltransferase (APRT), and adenosine kinase (AK) to purine salvage in Leishmania donovani, null mutants genetically deficient in HGPRT and/or APRT were generated by targeted gene replacement in wild type cells and preexisting mutant strains lacking either APRT or AK activity. These knockouts were obtained either by double targeted gene replacement or by single gene replacement followed by negative selection for loss-of-heterozygosity. Genotypes were confirmed by Southern blotting and the resultant phenotypes evaluated by enzymatic assay, resistance to cytotoxic drugs, ability to incorporate radiolabeled purine bases, and growth on various purine sources. All mutant strains could propagate in defined growth medium containing any single purine source and could metabolize exogenous [3H]hypoxanthine to the nucleotide level. The surprising ability of mutant L. donovani lacking HGPRT, APRT, and/or AK to incorporate and grow in hypoxanthine could be attributed to the ability of the parasite xanthine phosphoribosyltransferase enzyme to salvage hypoxanthine. These genetic studies indicate that HGPRT, APRT, and AK, individually or in any combination, are not essential for the survival and growth of the promastigote stage of L. donovani and intimate an important, if not crucial, role for xanthine phosphoribosyltransferase in purine salvage.
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Affiliation(s)
- H Y Hwang
- Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA
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43
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Svensson F, Ceriani C, Wallström EL, Kockum I, Algranati ID, Heby O, Persson L. Cloning of a trypanosomatid gene coding for an ornithine decarboxylase that is metabolically unstable even though it lacks the C-terminal degradation domain. Proc Natl Acad Sci U S A 1997; 94:397-402. [PMID: 9012793 PMCID: PMC19522 DOI: 10.1073/pnas.94.2.397] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Mammalian ornithine decarboxylase (ODC) is among the most labile of cellular proteins, with a half-life of usually less than an hour. Like other short-lived proteins ODC is degraded by the 26S proteasome. Its degradation is not triggered by ubiquitination, but is stimulated by the binding of an inducible protein, antizyme. Truncations and mutations in the C terminus of mammalian ODC have been shown to prevent the rapid turnover of the enzyme, demonstrating the presence of a degradation signal in this region. Moreover, ODCs from the trypanosomatid parasites Trypanosoma brucei and Leishmania donovani, which lack this C-terminal domain, are metabolically stable, and recombination of T. brucei ODC with the C terminus of mammalian ODC confers a short half-life to the fusion protein when expressed in mammalian cells. In the present study we have cloned and sequenced the ODC gene from the trypanosomatid Crithidia fasciculata. To our knowledge, this is the first protozoan shown to have an ODC with a rapid turnover. The sequence analysis revealed a high homology between C. fasciculata ODC and L. donovani ODC, despite the difference in stability. We demonstrate that C. fasciculata ODC has a very rapid turnover even when expressed in mammalian cells. Moreover, ODC from C. fasciculata is shown to lack the C-terminal degradation domain of mammalian ODC. Our findings indicate that C. fasciculata ODC contains unique signals, targeting the enzyme for rapid degradation not only in the parasite but also in mammalian cells.
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Affiliation(s)
- F Svensson
- Department of Physiology and Neuroscience, Lund University, Sweden
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44
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Abstract
The following observations are conjointly indicative of the presence of distinct energy-dependent, saturable and multiple polyamine transport systems in Leishmania donovani promastigotes, the causative agent for visceral leishmaniasis. Spermidine was influxed with as much as seven times higher rate than putrescine, while both spermidine and putrescine transporters exhibited equally high affinity for the respective polyamine. N-Ethylmaleimide arrested the complete functionality of both the transporters which could be restored by reduced glutathione. Putrescine transporter did not recognize spermine but spermidine was recognized to some extent, while spermidine transporter significantly recognized spermine but putrescine was absolutely spared. A few aromatic diamines viz., diaminobiphenyl and the analogs as well as aliphatic diamines viz., cadaverine and agmatine were selectively recognized by the putrescine transporter only. L. donovani promastigotes grown in presence of alpha-difluoromethylornithine, an irreversible inhibitor of ornithine decarboxylase, registered marked upregulation of putrescine transport while spermidine transport was only marginally induced. PA transport systems provide the alternative pool of polyamines in L. donovani promastigotes in the absence of an adequate intracellular PA repertoire.
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Affiliation(s)
- M Kandpal
- Division of Biochemistry, Central Drug Research Institute, Lucknow, India
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45
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Hwang HY, Gilberts T, Jardim A, Shih S, Ullman B. Creation of homozygous mutants of Leishmania donovani with single targeting constructs. J Biol Chem 1996; 271:30840-6. [PMID: 8940067 DOI: 10.1074/jbc.271.48.30840] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Homozygous null mutants of the hypoxanthine-guanine phosphoribosyltransferase (hgprt) and adenine phosphoribosyltransferase (aprt) loci were created in Leishmania donovani in which both alleles were eliminated using only a single targeting construct. Functional heterozygotes were first generated by homologous recombination after transfection with vectors containing 5'- and 3'-flanking regions of either the hgprt or the aprt gene circumscribing drug resistance markers. Homozygous null mutants were then isolated from the heterozygotes by negative selection in media containing subversive substrates of the encoded proteins, i.e. allopurinol for HGPRT and 4-aminopyrazolopyrimidine for APRT. The novel alleles created by homologous recombination were verified by Southern blotting, and the effects of gene replacement upon gene expression in intact parasites were evaluated by direct enzymatic assay and by immunoblotting. All mutant strains were viable under the selection conditions and exhibited appropriate drug resistance phenotypes. The ability to generate homozygous knockouts with single targeting constructs greatly facilitates the genetic dissection and subsequent biochemical investigations of the purine pathway in Leishmania and has important general implications for the genetic manipulation and analysis of the leishmanial genome.
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Affiliation(s)
- H Y Hwang
- Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA.
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46
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Wincker P, Ravel C, Blaineau C, Pages M, Jauffret Y, Dedet JP, Bastien P. The Leishmania genome comprises 36 chromosomes conserved across widely divergent human pathogenic species. Nucleic Acids Res 1996; 24:1688-94. [PMID: 8649987 PMCID: PMC145848 DOI: 10.1093/nar/24.9.1688] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
All the physical linkage groups constituting the genome of Leishmania infantum have been identified for the first time by hybridization of specific DNA probes to pulsed field gradient-separated chromosomes. The numerous co-migrating chromosomes were individualised using the distinctive size polymorphisms which occur among strains of the L. infantum/L. donovani complex as a tool. A total of 244 probes, consisting of 41 known genes, 66 expressed sequence tags (ESTs) and 137 anonymous DNA sequences, were assigned to a specific linkage group. We show that this genome comprises 36 chromosomes ranging in size from 0.35 to -3 Mb. This information enabled us to compare the genome structure of L. infantum with those of the three other main Leishmania species that infect man in the Old World, L. major, L. tropica and L. aethiopica. The linkage groups were consistently conserved in all species examined. This result is in striking contrast to the large genetic distances that separate these species and suggests that conservation of the chromosome structure may be critical for this human pathogen. Finally, the high density of markers obtained during the present study (with a mean of 1 marker/130 kb) will speed up the construction of a detailed physical map that would facilitate the genetic analysis of this parasite, for which no classical genetics is available.
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Affiliation(s)
- P Wincker
- Génome des Parasites, Laboratoire de Parasitologie, Faculté de Médecine, Montpellier, France
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47
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Mukhopadhyay R, Madhubala R. Leishmania donovani: cellular control of ornithine decarboxylase in promastigotes. Int J Biochem Cell Biol 1995; 27:947-52. [PMID: 7584631 DOI: 10.1016/1357-2725(95)00053-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ornithine decarboxylase, a key enzyme in polyamine biosynthesis, is essential for normal cell growth and proliferation. Furthermore, the inhibition of this enzyme is a potential way of controlling such growth. In order to shed light on the role of ornithine decarboxylase in regulation of Leishmania growth we examined the activity of this enzyme during the life cycle of these organisms. Exponentially growing Leishmania promastigotes were resuspended at a density of 3 x 10(6) cells/ml. 2 x 10(7) cells were withdrawn 24 hr later at different time intervals for induction studies and ornithine decarboxylase activity was measured. Ornithine decarboxylase showed a growth related pattern in L. donovani promastigotes. Induction studies showed that ornithine decarboxylase activity rapidly increased in late log phase cells when resuspended in fresh medium. A biphasic induction curve was observed similar to that observed in mammalian cells. The first peak was observed at 6 hr and the second at 16 hr. Cycloheximide and Actinomycin D inhibited induction at 16 hr by 65-68%. Polyamines at a level not inhibitory to growth (10 microM) inhibited ornithine decarboxylase induction by 30-40% late in the induction period. Putrescine and spermidine both inhibited the first peak of induction. Putrescine suppressed ornithine decarboxylase activity by 39% at 16 hr whereas spermidine by only 29%. The half life of ornithine decarboxylase in promastigote forms grown in the presence of cycloheximide was >6 hr. These studies indicate that although the Leishmanial ornithine decarboxylase follows a similar induction pattern to that previously reported in the mammalian cells, it is less susceptible to exogenous polyamines and is comparatively stable. This lack of ornithine decarboxylase regulation and turnover may be exploitable in the development of various therapeutic agents to inhibit Leishmanial growth.
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Affiliation(s)
- R Mukhopadhyay
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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48
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Allen TE, Hwang HY, Jardim A, Olafson R, Ullman B. Cloning and expression of the hypoxanthine-guanine phosphoribosyltransferase from Leishmania donovani. Mol Biochem Parasitol 1995; 73:133-43. [PMID: 8577321 DOI: 10.1016/0166-6851(94)00105-v] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The gene encoding the hypoxanthine-guanine phosphoribosyltransferase (HGPRT) enzyme from Leishmania donovani has been cloned and sequenced. The hgprt open reading frame encoded a polypeptide of 211 amino acids that exhibited 3 regions of significant homology with other eukaryotic HGPRTs and a C-terminal tripeptide compatible with a glycosomal targeting signal. Northern blot analysis of L. donovani RNA revealed two hgprt transcripts, a 1.9-kb mRNA and a 1.7-kb transcript. The expression of the 1.7-kb hgprt mRNA and the activity of HGPRT enzyme were both augmented approx. 5-fold in parasites incubated in the absence of purines. Southern blots of genomic DNA indicated only a single hgprt locus within the L. donovani genome. Overexpression of L. donovani hgprt in E. coli complemented genetic deficiencies in hypoxanthine and guanine phosphoribosylating activities and yielded abundant quantities of enzymatically active HGPRT. The recombinant HGPRT was purified to homogeneity and recognized hypoxanthine, guanine and allopurinol, but not adenine or xanthine, as substrates. The hgprt clone and pure HGPRT protein provide essential reagents for validating HGPRT as a therapeutic target for the treatment of leishmaniasis and other diseases of parasitic origin.
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Affiliation(s)
- T E Allen
- Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland 97201-3098, USA
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49
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Reguera RM, Fouce RB, Cubría JC, Bujidos ML, Ordóñez D. Fluorinated analogues of L-ornithine are powerful inhibitors of ornithine decarboxylase and cell growth of Leishmania infantum promastigotes. Life Sci 1994; 56:223-30. [PMID: 7823781 DOI: 10.1016/0024-3205(94)00916-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fluorinated analogues of L-ornithine have been tested on growth and ornithine decarboxylase arising from L.infantum cytosolic extracts. EC50 values estimated from dose/response curves were 38 microM, 2.62 microM and 4.64 microM for alpha-DFMO, delta-MFMO and delta-MFMOme respectively. Also the inhibition produced by all three compounds was effectively reverted by exogenous putrescine, pointing towards the inhibition of L.infantum ODC. ODC from logarithmic phase cytosolic extracts was physicochemically and kinetically characterized, showing a long half-life (more than 24 h) and a km value for L-ornithine of 98 microM. Finally, the inhibitory effect of fluorinated analogues of L-ornithine was analysed on L.infantum ODC showing a time-dependent irreversible behavior, with Ki values estimated on 125 microM, T1/2 3.5 min for alpha-DFMO; 13.3 microM, T1/2 1.8 min for delta-MFMO and 4.3 microM, T1/2 4 min for delta-MFMOme.
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Affiliation(s)
- R M Reguera
- Departamento de Fisiología, Farmacología y Toxicología, Facultad de Veterinaria, Universidad de León, Spain
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Wilson K, Berens RL, Sifri CD, Ullman B. Amplification of the inosinate dehydrogenase gene in Trypanosoma brucei gambiense due to an increase in chromosome copy number. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(19)62002-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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