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Rivara-Espasandín M, Palumbo MC, Sosa EJ, Radío S, Turjanski AG, Sotelo-Silveira J, Fernandez Do Porto D, Smircich P. Omics data integration facilitates target selection for new antiparasitic drugs against TriTryp infections. Front Pharmacol 2023; 14:1136321. [PMID: 37089958 PMCID: PMC10115950 DOI: 10.3389/fphar.2023.1136321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/28/2023] [Indexed: 04/09/2023] Open
Abstract
Introduction:Trypanosoma cruzi, Trypanosoma brucei, and Leishmania spp., commonly referred to as TriTryps, are a group of protozoan parasites that cause important human diseases affecting millions of people belonging to the most vulnerable populations worldwide. Current treatments have limited efficiencies and can cause serious side effects, so there is an urgent need to develop new control strategies. Presently, the identification and prioritization of appropriate targets can be aided by integrative genomic and computational approaches.Methods: In this work, we conducted a genome-wide multidimensional data integration strategy to prioritize drug targets. We included genomic, transcriptomic, metabolic, and protein structural data sources, to delineate candidate proteins with relevant features for target selection in drug development.Results and Discussion: Our final ranked list includes proteins shared by TriTryps and covers a range of biological functions including essential proteins for parasite survival or growth, oxidative stress-related enzymes, virulence factors, and proteins that are exclusive to these parasites. Our strategy found previously described candidates, which validates our approach as well as new proteins that can be attractive targets to consider during the initial steps of drug discovery.
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Affiliation(s)
- Martin Rivara-Espasandín
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
- Departamento de Genética, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Miranda Clara Palumbo
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ezequiel J. Sosa
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Ciudad Universitaria, Buenos Aires, Argentina
| | - Santiago Radío
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Adrián G. Turjanski
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Ciudad Universitaria, Buenos Aires, Argentina
| | - José Sotelo-Silveira
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
- Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Dario Fernandez Do Porto
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- *Correspondence: Dario Fernandez Do Porto, ; Pablo Smircich,
| | - Pablo Smircich
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
- Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- *Correspondence: Dario Fernandez Do Porto, ; Pablo Smircich,
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Ali V, Behera S, Nawaz A, Equbal A, Pandey K. Unique thiol metabolism in trypanosomatids: Redox homeostasis and drug resistance. ADVANCES IN PARASITOLOGY 2022; 117:75-155. [PMID: 35878950 DOI: 10.1016/bs.apar.2022.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Trypanosomatids are mainly responsible for heterogeneous parasitic diseases: Leishmaniasis, Sleeping sickness, and Chagas disease and control of these diseases implicates serious challenges due to the emergence of drug resistance. Redox-active biomolecules are the endogenous substances in organisms, which play important role in the regulation of redox homeostasis. The redox-active substances like glutathione, trypanothione, cysteine, cysteine persulfides, etc., and other inorganic intermediates (hydrogen peroxide, nitric oxide) are very useful as defence mechanism. In the present review, the suitability of trypanothione and other essential thiol molecules of trypanosomatids as drug targets are described in Leishmania and Trypanosoma. We have explored the role of tryparedoxin, tryparedoxin peroxidase, ascorbate peroxidase, superoxide dismutase, and glutaredoxins in the anti-oxidant mechanism and drug resistance. Up-regulation of some proteins in trypanothione metabolism helps the parasites in survival against drug pressure (sodium stibogluconate, Amphotericin B, etc.) and oxidative stress. These molecules accept electrons from the reduced trypanothione and donate their electrons to other proteins, and these proteins reduce toxic molecules, neutralize reactive oxygen, or nitrogen species; and help parasites to cope with oxidative stress. Thus, a better understanding of the role of these molecules in drug resistance and redox homeostasis will help to target metabolic pathway proteins to combat Leishmaniasis and trypanosomiases.
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Affiliation(s)
- Vahab Ali
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India.
| | - Sachidananda Behera
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
| | - Afreen Nawaz
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
| | - Asif Equbal
- Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India; Department of Botany, Araria College, Purnea University, Purnia, Bihar, India
| | - Krishna Pandey
- Department of Clinical Medicine, ICMR-Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna, Bihar, India
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3
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Hirth B, Barker RH, Celatka CA, Klinger JD, Liu H, Nare B, Nijjar A, Phillips MA, Sybertz E, Willert EK, Xiang Y. Discovery of new S-adenosylmethionine decarboxylase inhibitors for the treatment of Human African Trypanosomiasis (HAT). Bioorg Med Chem Lett 2009; 19:2916-9. [PMID: 19419862 DOI: 10.1016/j.bmcl.2009.04.096] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 04/16/2009] [Accepted: 04/21/2009] [Indexed: 10/20/2022]
Abstract
Modification of the structure of trypanosomal AdoMetDC inhibitor 1 (MDL73811) resulted in the identification of a new inhibitor 7a, which features a methyl substituent at the 8-position. Compound 7a exhibits improved potencies against both the trypanosomal AdoMetDC enzyme and parasites, and better blood brain barrier penetration than 1.
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Affiliation(s)
- Bradford Hirth
- Drug and Biomaterial R&D, Genzyme Corporation, Waltham, MA 02451, United States
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4
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Novel S-adenosylmethionine decarboxylase inhibitors for the treatment of human African trypanosomiasis. Antimicrob Agents Chemother 2009; 53:2052-8. [PMID: 19289530 DOI: 10.1128/aac.01674-08] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Trypanosomiasis remains a significant disease across the sub-Saharan African continent, with 50,000 to 70,000 individuals infected. The utility of current therapies is limited by issues of toxicity and the need to administer compounds intravenously. We have begun a program to pursue lead optimization around MDL 73811, an irreversible inhibitor of S-adenosylmethionine decarboxylase (AdoMetDC). This compound is potent but in previous studies cleared rapidly from the blood of rats (T. L. Byers, T. L. Bush, P. P. McCann, and A. J. Bitonti, Biochem. J. 274:527-533). One of the analogs synthesized (Genz-644131) was shown to be highly active against Trypanosoma brucei rhodesiense in vitro (50% inhibitory concentration, 400 pg/ml). Enzyme kinetic studies showed Genz-644131 to be approximately fivefold more potent than MDL 73811 against the T. brucei brucei AdoMetDC-prozyme complex. This compound was stable in vitro in rat and human liver microsomal and hepatocyte assays, was stable in rat whole-blood assays, did not significantly inhibit human cytochrome P450 enzymes, had no measurable efflux in CaCo-2 cells, and was only 41% bound by serum proteins. Pharmacokinetic studies of mice following intraperitoneal dosing showed that the half-life of Genz-644131 was threefold greater than that of MDL 73811 (7.4 h versus 2.5 h). Furthermore, brain penetration of Genz-644131 was 4.3-fold higher than that of MDL 73811. Finally, in vivo efficacy studies of T. b. brucei strain STIB 795-infected mice showed that Genz-644131 significantly extended survival (from 6.75 days for controls to >30 days for treated animals) and cured animals infected with T. b. brucei strain LAB 110 EATRO. Taken together, the data strengthen validation of AdoMetDC as an important parasite target, and these studies have shown that analogs of MDL 73811 can be synthesized with improved potency and brain penetration.
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Nishimura K, Yanase T, Araki N, Ohnishi Y, Kozaki S, Shima K, Asakura M, Samosomsuk W, Yamasaki S. EFFECTS OF POLYAMINES ON TWO STRAINS OF TRYPANOSOMA BRUCEI IN INFECTED RATS AND IN VITRO CULTURE. J Parasitol 2006; 92:211-7. [PMID: 16729674 DOI: 10.1645/ge-633r.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We studied the effects of polyamines, which are necessary for proliferation and antioxidation in Trypanosoma brucei gambiense Wellcome strain (WS) and Trypanosoma brucei brucei ILtat 1.4 strain (IL). No difference was found in activity of ornithine decarboxylase (ODC), a key enzyme in polyamine synthesis in trypanosomes, in both strains maintained in vitro; higher (P < 0.05) ODC values were found in IL in vivo. However, WS in vivo exhibited higher proliferation rates with higher spermidine content and decreased host survival times than IL. The in vitro proliferation and polyamine contents of WS increased with the addition of polyamine to the 1-difluoromethylornithine culture medium, but not IL. These results suggested that WS uses extracellular polyamine for proliferation. In the in vitro culture, WS was less tolerant of hydrogen peroxide (oxidative stress) than IL, and malondialdehyde levels in WS were higher than in IL. The expression of trypanothione synthetase mRNA in WS in vitro was higher than in IL. These results suggest that IL is dependent on the synthesis of polyamines for proliferation and reduction of oxidative stress, whereas WS is dependent on the uptake of extracellular polyamines. A thorough understanding of the differences in the metabolic capabilities of various trypanosomes is important for the design of more effective medical treatments.
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Affiliation(s)
- Kazuhiko Nishimura
- Course of Veterinary Science, Graduate School Life and Environmental Sciences, Osaka Prefecture University 1-1, Gakuencho, Sakai, Osaka 599-8531, Japan.
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6
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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: 57] [Impact Index Per Article: 2.6] [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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7
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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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8
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Nishimura K, Araki N, Ohnishi Y, Kozaki S. Effects of dietary polyamine deficiency on Trypanosoma gambiense infection in rats. Exp Parasitol 2001; 97:95-101. [PMID: 11281706 DOI: 10.1006/expr.2000.4588] [Citation(s) in RCA: 18] [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
Nishimura, K., Araki, N., Ohnishi, Y., and Kozaki, S. 2001. Effects of dietary polyamine deficiency on Trypanosoma gambiense infection in rats. Experimental Parasitology 97, 95-101. A diet deficient in polyamines decreases the availability of dietary polyamines. We used rats infected with the Wellcome strain of Trypanosoma gambiense to examine the effects of polyamine-deficient chow (PDC) on trypanosome proliferation and symptoms of infection. Rats fed PDC showed limited increase of trypanosome and symptoms of infection and limited loss of body weight and anemia. Survival in these rats was prolonged. Before infection, the heparinized plasma concentration of spermidine in the PDC-fed rats was lower than that in control rats fed with standard chow. After infection, the content of spermidine in red blood cells increased in the control rats, but was only slightly increased in PDC-fed rats. The content of spermidine in the trypanosomes after infection was low in the PDC-fed rats. Decreases in the polyamine content of trypanosomes limited their increase. These observations suggest that a reduction in dietary polyamines may help in the regulation of trypanosome infection.
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Affiliation(s)
- K Nishimura
- Department of Veterinary Science, College of Agriculture, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
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9
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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: 81] [Impact Index Per Article: 3.4] [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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Basselin M, Badet-Denisot MA, Lawrence F, Robert-Gero M. Effects of pentamidine on polyamine level and biosynthesis in wild-type, pentamidine-treated, and pentamidine-resistant Leishmania. Exp Parasitol 1997; 85:274-82. [PMID: 9085924 DOI: 10.1006/expr.1996.4131] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Polyamine biosynthesis was studied in wild-type promastigotes of Leishmania donovani and Leishmania amazonensis treated with pentamidine and in the parasites resistant to this drug. Treatment of wild-type clones with low pentamidine concentrations for 24 hr provoked a strong decrease in arginine, ornithine, and putrescine pools, while the level of intracellular spermidine remained unchanged. In these cells, the activity of the enzyme ornithine decarboxylase was found to be decreased. Compared to wild-type cells, resistant clones had a lower level of putrescine, higher pools of arginine and ornithine, and a similar spermidine content. Analysis by Western blot and DFMO-binding showed reduced amount of ornithine decarboxylase. Furthermore, in the resistant cells, the kinetic parameters of the enzyme spermidine synthase were markedly changed, showing increased affinity to putrescine and decreased affinity to pentamidine. Thus, it seems that polyamine biosynthesis pathway is a target of pentamidine in Leishmania and is altered in resistant clones.
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Affiliation(s)
- M Basselin
- Institut de Chimie des Substances Naturelles, CNRS, Gif-sur-Yvette, France
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11
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Calonge M, Johnson R, Balaña-Fouce R, Ordóñez D. Effects of cationic diamidines on polyamine content and uptake on Leishmania infantum in in vitro cultures. Biochem Pharmacol 1996; 52:835-41. [PMID: 8781500 DOI: 10.1016/0006-2952(96)00348-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effect of a series of cationic diamidines recently synthesized by Ciba Geigy, bearing diarylic (CGP040215A and CGP039937A) or monoarylic moieties (CGP033829A, CGP035537A and CGP036958A), was analyzed on some metabolic targets and cell proliferation of in vitro cultures of Leishmania infantum promastigotes (insect form). The action of these compounds on intracellular polyamine pools and putrescine transport suggests that diarylic structures were more effective than their monoarylic counterparts in depleting polyamine levels and inhibiting putrescine transport, although these processes correlate poorly with the antiproliferative rate of these compounds. Finally, the displacement of cationic diamidines to kDNA observed in the presence of several concentrations of spermidine suggests a possible combined mode of action of these molecules, first depleting intracellular polyamine pools and, then, displacing spermidine from its site of interaction to kDNA.
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Affiliation(s)
- M Calonge
- Departmento de Fisiología, Farmacología y Toxicología, Universidad de León, Spain
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12
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Baer HP, Schmidt K, Mayer B, Kukovetz WR. Pentamidine does not interfere with nitrite formation in activated RAW 264.7 macrophages but inhibits constitutive brain nitric oxide synthase. Life Sci 1995; 57:1973-80. [PMID: 7475946 DOI: 10.1016/0024-3205(95)02183-j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Pentamidine effects on the interferon-gamma- or interferon-gamma plus bacterial lipopolysaccharide-induction of nitric oxide synthase in the macrophage cell line RAW 264.7, determined by measuring nitrite release into culture supernatants, were investigated. At concentrations above 10 microM, pentamidine caused visible toxic effects including cell lysis which also was assessed by measuring lactic dehydrogenase release. A progressive inhibitory effect of pentamidine could not be clearly dissociated from these toxic and lytic effects which were extensive at 100 microM. At 1 microM pentamidine, the dose response dependence of nitrite formation on interferon-gamma was not affected. Tumor necrosis factor-alpha caused some enhancement of interferon-gamma-induced nitrite release only at high doses of 100 and 10,000 unit/ml. Pentamidine had no effect on isolated inducible nitric oxide synthase from RAW 264.7 cells but inhibited the constitutive enzyme from pork cerebellum non-competitively. The lack of any stimulatory effect of pentamidine on nitrite production in RAW 264.7 cells suggests that NOS induction and NO production by macrophages is not the mechanism of the antimicrobial effects of this drug.
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Affiliation(s)
- H P Baer
- Institut für Pharmakologie and Toxikologie, Karl-Franzens-Universität Graz, Austria
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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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Peregrine AS, Eisler MC, Katende J, Flynn JN, Gault EA, Kinabo LD, Holmes PH. Generation of monoclonal antibodies to the anti-trypanosomal drug isometamidium. Hybridoma (Larchmt) 1994; 13:289-94. [PMID: 7806249 DOI: 10.1089/hyb.1994.13.289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Mice were immunized with either an isometamidium-human serum albumin (HSA) conjugate or an isometamidium-porcine thyroglobulin conjugate (PTG). Thereafter, monoclonal antibodies (MAbs) IL-A 1001, IL-A 1002, IL-A 1003, 5F7.B7, and 5F7.C9 were generated and selected on the basis that they recognized conjugated and unconjugated isometamidium, but lacked cross-reactivity with the carrier molecules. All five MAbs were of the IgG1 isotype. Each of the five MAbs was assessed in a competitive ELISA for isometamidium; in each case, the minimum level of detection was approximately 10 ng/ml. Each MAb exhibited approximately 0.1% cross-reactivity with the anti-trypanosomal compound diminazene. However, based on their cross-reactivity with the anti-trypanosomal compound homidium, the MAbs could be divided into two groups; IL-A 1001, IL-A 1002, and IL-A 1003, produced using an isometamidium-HSA conjugate as an immunogen, exhibited low levels of cross-reactivity (approximately 0.1%). In contrast, 5F7.B7 and 5F7.C9, produced using an isometamidium-PTG conjugate as an immunogen, exhibited high levels of cross-reactivity.
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Affiliation(s)
- A S Peregrine
- International Laboratory for Research on Animal Diseases (ILRAD), Nairobi, Kenya
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Osuna A, Rodriguez-Cabezas N, Gamarro F, Mascaro C. The different behavior of diphtheria toxin, modeccin and ricin in HeLa cells infected with Trypanosoma cruzi. J Eukaryot Microbiol 1994; 41:231-6. [PMID: 8049687 DOI: 10.1111/j.1550-7408.1994.tb01503.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have studied the action of diphtheria toxin, modeccin and ricin on HeLa cells infected by Trypanosoma cruzi. Parasitized HeLa cells were resistant to diphtheria toxin and modeccin, whereas non-parasitized cells from the same cultures and control cultures showed cytopathological alterations. Protein synthesis, assayed by the incorporation of labelled methionine, diminished in toxin-treated control cultures but remained unaltered in the infected ones, compared to synthesis by untreated infected cells. Ricin, on the other hand, is a toxin that enters the cytoplasm by endocytosis. It has greater cytopathological effects in parasitized cells than in non-parasitized ones from the same cultures or uninfected control cells. Protein synthesis was inhibited in infected cultures treated with ricin.
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Affiliation(s)
- A Osuna
- Departamento de Parasitología, Facultad de Ciencias, Universidad de Granada, Spain
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16
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Carrera L, Balaña-Fouce R, Alunda JM. Polyamine content and drug sensitivities of different clonal lines of Leishmania infantum promastigotes. Parasitol Res 1994; 80:203-7. [PMID: 8036233 DOI: 10.1007/bf00932675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Two isolates (skin and lymph node) of Leishmania infantum obtained from a naturally infected dog were cloned and the free pools of polyamines for both complete isolates and clones were determined. Putrescine (Put) and spermidine (Spd) levels were highly variable among the lines studied, ranging from 0.89 to 2.1 nmol Spd/10(7) promastigotes. The Put/Spd ratio was also variable (1.54-0.51) and correlated with the cell growth of the lines studied. There were important differences in the clones' sensitivities to difluoromethylornithine (DFMO) and Berenil, with some of the clones being almost refractory to the inhibitory effect of 50 microM DFMO, whereas the growth of others was reduced by 60%; similar findings were obtained with 50 microM Berenil. L. infantum sensitivities to DFMO and Berenil were correlated and apparently related to the values for the Put/Spd index.
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Affiliation(s)
- L Carrera
- Departamento de Patología Animal I, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain
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17
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Hugo ER, Byers TJ. S-adenosyl-L-methionine decarboxylase of Acanthamoeba castellanii (Neff): purification and properties. Biochem J 1993; 295 ( Pt 1):203-9. [PMID: 8216217 PMCID: PMC1134839 DOI: 10.1042/bj2950203] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
S-Adenosyl-L-methionine decarboxylase (AdoMetDC) has been purified to near homogeneity from the Neff strain of Acanthamoeba castellanii. The holoenzyme molecular mass is 88.8 kDa, including two copies each of a 32.8 kDa alpha-subunit and a 10-15 kDa beta-subunit. The alpha-subunit contains the active site. It has an N-terminal pyruvoyl group, and the first 19 amino acids are 63 and 74% identical with comparable sequences from yeast and mammals, respectively. The apparent Km for S-adenosylmethionine (AdoMet) in the presence of 2 mM putrescine was 30.0 microM. The enzyme was stimulated 2-fold by putrescine, but was unaffected by spermidine. It was inhibited by the following anti-metabolites, listed with their Ki values: Berenil (0.17 microM), pentamidine (19.4 microM), propamidine (334 microM), hydroxystilbamidine (357 microM), methylglyoxal bis(guanylhydrazone) (604 microM) and ethidium bromide (1.3 mM). Activity of the enzyme fell to undetectable levels during cell differentiation (encystment).
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Affiliation(s)
- E R Hugo
- Department of Molecular Genetics, Ohio State University, Columbus 43210
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18
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Abstract
Chemotherapy for trypanosomiasis in domestic livestock depends on only a few compounds, of which several are chemically closely related. Of these compounds, the most widely used therapeutic agent in cattle, sheep and goats is diminazene aceturate. Diminazene was first described in 1955. Subsequently, a substantial body of data has been generated on various pharmacological aspects of the compound. In this review, we consider the current status of knowledge concerning the therapeutic spectrum of diminazene, resistance to diminazene in trypanosomes, and combination therapeutic regimens in which diminazene has been administered together with other compounds. Analytical techniques for diminazene, the pharmacokinetics of diminazene, data concerning diminazene's toxicity, and the different molecular mechanisms by which diminazene may exhibit trypanocidal action are also considered.
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Affiliation(s)
- A S Peregrine
- International Laboratory for Research on Animal Diseases (ILRAD), Nairobi, Kenya
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19
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Zilberstein D, Wilkes J, Hirumi H, Peregrine AS. Fluorescence analysis of the interaction of isometamidium with Trypanosoma congolense. Biochem J 1993; 292 ( Pt 1):31-5. [PMID: 8503859 PMCID: PMC1134264 DOI: 10.1042/bj2920031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Isometamidium chloride (Samorin) is the only compound recommended for prophylaxis against bovine trypanosomiasis in sub-Saharan Africa. The fluorescence property of this compound was used to investigate the interaction of the molecule with in vitro-derived bloodstream forms of Trypanosoma congolense IL 1180. Incubation of isometamidium with trypanosomes at 37 degrees C for 180 min resulted in a gradual alteration of the lambda max. with time (from 600 to 584 nm) and an increase in the intensity of trypanosome-associated fluorescence of approx. 2-fold. The alteration in fluorescence was temperature-dependent and inhibited by the addition of N-ethylmaleimide. In contrast, with intact cells addition of digitonin caused a rapid increase in fluorescence intensity to approximately four times that observed with intact cells. Uptake of isometamidium was also determined using radiolabelled drug; the results indicated that the time course of the uptake process resembled the fluorescence profile and was temperature-dependent. The results therefore indicate that the alteration of fluorescence is due to interaction of isometamidium with an intracellular component(s) and that isometamidium is transported across the plasma membrane via a protein carrier. The data also indicate that the described fluorescence technique can be used to investigate the role of membrane transport in resistance to isometamidium.
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Affiliation(s)
- D Zilberstein
- Department of Biology, Technion, Israel Institute of Technology, Technion City, Haifa
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20
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Tekwani BL, Bacchi CJ, Pegg AE. Putrescine activated S-adenosylmethionine decarboxylase from Trypanosoma brucei brucei. Mol Cell Biochem 1992; 117:53-61. [PMID: 1480164 DOI: 10.1007/bf00230410] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Trypanosoma brucei brucei contained a S-adenosyl-L-methionine decarboxylase (AdoMetDC) strongly activated by putrescine. The enzyme was also activated to a lesser extent by cadaverine and 1,3-diaminopropane. Spermidine and spermine had no effect on basal activity of the enzyme. However, they interfered with putrescine activation of trypanosomal AdoMetDC. The trypanosomal enzyme could not be precipitated with antiserum against human AdoMetDC. The trypanosomal AdoMetDC enzyme subunit was labeled by reaction with 35S-decarboxylated AdoMet in the presence of NaCNBH4, and found to have a molecular weight of 34 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The subunit was readily degraded on storage to a form with a molecular weight of 26 kDa. The specificity of labeling of AdoMetDC by this procedure was confirmed by the prevention of 35S-decarboxylated S-adenosylmethionine (AdoMet) binding in the presence of specific AdoMetDC inhibitors [either methylglyoxal bis(guanylhydrazone (MGBG), a reversible inhibitor, or 5'-deoxy-5'-[(2-hydrazinoethyl)methylamino]adenosine (MHZEA), an irreversible inactivator]. As compared to human AdoMetDC, the trypanosomal enzyme showed weaker binding to a column of MGBG-Sepharose and also was significantly less sensitive to inhibition by MGBG and its congener ethylglyoxal bis(guanylhydrazone) (EGBG). Thus, the trypanosomal AdoMetDC differs significantly from its mammalian and bacterial counterparts and may therefore be exploited as a specific target for chemotherapy of trypanosomiasis.
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Affiliation(s)
- B L Tekwani
- Department of Cellular & Molecular Physiology, Milton S. Hershey Medical Center Pennsylvania State University College of Medicine, Hershey 17033
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21
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Libby PR, Porter CW. Inhibition of enzymes of polyamine back-conversion by pentamidine and berenil. Biochem Pharmacol 1992; 44:830-2. [PMID: 1510731 DOI: 10.1016/0006-2952(92)90424-h] [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: 12/27/2022]
Abstract
Pentamidine and berenil, clinical antiparasitic amidines, have been found to be potent competitive inhibitors of human spermidine/spermine acetyltransferase (SSAT). Ki values were found to be 2.4 and 2 microM, respectively, with spermidine as substrate. A second enzyme of polyamine back-conversion, murine polyamine oxidase (PAO), was found to be competitively inhibited by pentamidine, with a Ki of 7.6 microM when N-acetylspermine was the substrate. Berenil, on the other hand, was an extremely weak inhibitor (Ki = 120 microM). The implication of the effect of inhibition of polyamine back-conversion on the growth of mammalian parasites is discussed.
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Affiliation(s)
- P R Libby
- Grace Cancer Drug Center, Roswell Park Cancer Institute, Buffalo, NY 14263
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22
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Abstract
The polyamines putrescine, spermidine and spermine represent a group of naturally occurring compounds exerting a bewildering number of biological effects, yet despite several decades of intensive research work, their exact physiological function remains obscure. Chemically these compounds are organic aliphatic cations with two (putrescine), three (spermidine) or four (spermine) amino or amino groups that are fully protonated at physiological pH values. Early studies showed that the polyamines are closely connected to the proliferation of animal cells. Their biosynthesis is accomplished by a concerted action of four different enzymes: ornithine decarboxylase, adenosylmethionine decarboxylase, spermidine synthase and spermine synthase. Out of these four enzyme, the two decarboxylases represent unique mammalian enzymes with an extremely short half life and dramatic inducibility in response to growth promoting stimuli. The regulation of ornithine decarboxylase, and to some extent also that of adenosylmethionine decarboxylase, is complex, showing features that do not always fit into the generally accepted rules of molecular biology. The development and introduction of specific inhibitors to the biosynthetic enzymes of the polyamines have revealed that an undisturbed synthesis of the polyamines is a prerequisite for animal cell proliferation to occur. The biosynthesis of the polyamines thus offers a meaningful target for the treatment of certain hyperproliferative diseases, most notably cancer. Although most experimental cancer models responds strikingly to treatment with polyamine antimetabolites--namely, inhibitors of various polyamine synthesizing enzymes--a real breakthrough in the treatment of human cancer has not yet occurred. It is, however, highly likely that the concept is viable. An especially interesting approach is the chemoprevention of cancer with polyamine antimetabolites, a process that appears to work in many experimental animal models. Meanwhile, the inhibition of polyamine accumulation has shown great promise in the treatment of human parasitic diseases, such as African trypanosomiasis.
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Affiliation(s)
- J Jänne
- Department of Biochemistry & Biotechnology, University of Kuopio, Finland
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23
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Sharma V, Tekwani BL, Saxena JK, Gupta S, Katiyar JC, Chatterjee RK, Ghatak S, Shukla OP. Polyamine metabolism in some helminth parasites. Exp Parasitol 1991; 72:15-23. [PMID: 1993461 DOI: 10.1016/0014-4894(91)90116-e] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Polyamine levels of some helminth parasites were analyzed by reverse phase HPLC of benzoyl derivatives. Setaria cervi, Acanthocheilonema viteae, Hymenolepis nana, H. diminuta, and Ascaridia galli contained higher levels of spermine than spermidine while in Ancylostoma ceylanicum and Nippostrongylus brasiliensis the spermidine levels were higher than spermine; putrescine was either absent or present in minor quantities. The enzymes of polyamine biosynthesis viz., ornithine decarboxylase, S-adenosyl methionine (SAM)-decarboxylase, and arginine decarboxylase were present in very low to negligible amounts in all the parasites examined. A. ceylanicum exhibited high activity of ornithine amino transferase (OAT) and catalyzed appreciable decarboxylation of ornithine. The ornithine decarboxylating activity of A. ceylanicum was localized in the particulate fraction containing mitochondria, not inhibited by alpha-difluoromethyl ornithine, the specific inhibitor of ornithine decarboxylase (ODC), but inhibited in the presence of glutamate, suggesting the involvement of mitochondrial OAT rather than a true ODC in ornithine decarboxylation in this parasite. Significant activity of polyamine oxidase was also detected in helminth parasites. The absence of polyamine biosynthesizing enzymes in helminth parasites suggests their dependence on hosts for uptake and interconversion of polyamines, providing a potential target for chemotherapy.
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Affiliation(s)
- V Sharma
- Division of Biochemistry, Central Drug Research Institute, Lucknow, India
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24
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Balaña-Fouce R, Escribano MI, Alunda JM. Leishmania infantum: polyamine biosynthesis and levels during the growth of promastigotes. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1991; 23:1213-7. [PMID: 1794446 DOI: 10.1016/0020-711x(91)90218-c] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. Decarboxylation of polyamine precursors: L-ornithine and L-methionine was determined along the growth curve of Leishmania infantum promastigotes in vivo, reaching maximum values on day 2 post-inoculum (mid-logarithmic phase). 2. Maximum values of L-ornithine and L-methionine decarboxylation were: 1.97 +/- 0.28 nmol CO2/hr/10(7) promastigotes and 3.18 +/- 0.34 nmol CO2/hr/10(7) promastigotes, respectively. 3. Total (free + conjugated) polyamine content was closely related with the proliferative stage of Leishmania infantum promastigotes. 4. D,L-alpha-difluoromethylornithine (DFMO) and Berenil depleted putrescine levels in a concentration-dependent manner. 5. Total and free putrescine/spermidine ratio varied significantly with the proliferative stage. Minimum values were found in late logarithmic phase (day 3 post-inoculum). 6. Small but detectable amounts of free spermine were detectable along the growth curve of Leishmania infantum promastigotes.
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Affiliation(s)
- R Balaña-Fouce
- Departamento Fisiología y Farmacología y Toxicología, Ftad, Veterinaria, Universidad de León, Spain
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25
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Abstract
DL-alpha-Difluoromethylornithine (DFMO), a suicide inhibitor of eukaryotic ornithine decarboxylase (ODC), has therapeutic activities against African trypanosomiasis. The Ki value of DFMO for ODC of Trypanosoma brucei is somewhat higher than that for mouse ODC. The therapeutic efficacy of DFMO cannot therefore be attributed to a preferential inhibition of the parasite enzyme. The T. brucei gene encoding ODC was cloned and sequenced, and the derived amino acid sequence has 61.5% homology with that of mouse ODC, except that the C-terminal 36 amino acids of the mouse enzyme are missing from the parasite enzyme. The cloned T. brucei and mouse ODC genes were expressed in ODC-deficient Chinese hamster ovary cells (CHO) where the T. brucei enzyme was stable, but mouse ODC was unstable. Thus, the observed difference in intracellular stability is a property of the ODC protein itself, rather than of the cellular environment in which it is expressed. A chimeric ODC composed of the amino terminus of trypanosome ODC and the C-terminus of mouse ODC also was rapidly degraded in CHO cells, suggesting that peptide sequences in the mouse ODC carboxy-terminus determine its stability. The relatively slow turnover of the parasite enzyme constitutes the basis of selective antitrypanosomal action of DFMO. By this same token, many other proteins known to perform crucial functions in bacteria, fungi, protozoa, helminths, etc., also may have shorter half-lives in the mammalian hosts than in parasites. Suicide inhibitors of these proteins may have desirable characteristics as good chemotherapeutic agents. This new approach could provide an additional strategy for controlling infectious diseases.
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Affiliation(s)
- C C Wang
- Department of Pharmaceutical Chemistry, University of California, San Francisco 94143-0446
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26
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Pfaller MA, Riley J, Gerarden T. Polyamine depletion and growth inhibition of Cryptococcus neoformans by alpha-difluoromethylornithine and cyclohexylamine. Mycopathologia 1990; 112:27-32. [PMID: 2250691 DOI: 10.1007/bf01795176] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The ability of two known inhibitors of polyamine synthesis alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase (ODC), and cyclohexylamine, an inhibitor of spermidine synthase, to inhibit the in vitro growth and polyamine synthesis of clinical isolates of Cryptococcus neoformans was examined. Treatment of C. neoformans with either DFMO or cyclohexylamine resulted in depletion of cellular polyamines and inhibition of growth. Cryptococcus neoformans was shown to lack detectable spermine and to require high concentrations of spermidine, but not putrescine, for growth. The growth inhibition by DFMO and cyclohexylamine was reversed by exogenous polyamines. These findings document the ability of cyclohexylamine and DFMO to inhibit polyamine synthesis and growth in clinically important isolates of C. neoformans.
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Affiliation(s)
- M A Pfaller
- Veterans Administration Medical Center, Iowa City, IA
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27
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Onyeyili PA, Anika SM. Effects of the combination of DL-alpha-difluoromethylornithine and diminazene aceturate in Trypanosoma congolense infection of dogs. Vet Parasitol 1990; 37:9-19. [PMID: 2238433 DOI: 10.1016/0304-4017(90)90021-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The therapeutic activity of a combination of difluoromethylornithine (DFMO) with diminazene aceturate was investigated in mongrel dogs experimentally infected with Trypanosoma congolense. The criteria used in the assessment of the trypanocidal effect of the therapy include the examination of the blood for parasites, as well as clinical and haematological changes at intervals following treatment. Diminazene aceturate and DFMO alone and in combination produced intermittent aparasitaemia in the dogs. Although relapse infection occurred with all three treatment regimes, the drug combination gave the best result. The packed red cell volume, haemoglobin concentrations and red blood cell values decreased significantly following parasite inoculation but increased after treatment. The total leucocyte counts decreased in all the infected dogs but improved with treatment, and the differential leucocyte counts indicated neutropenia in all the infected animals prior to treatment.
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Affiliation(s)
- P A Onyeyili
- Department of Veterinary Physiology and Pharmacology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka
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28
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Cure of Trypanosoma brucei brucei and Trypanosoma brucei rhodesiense infections in mice with an irreversible inhibitor of S-adenosylmethionine decarboxylase. Antimicrob Agents Chemother 1990; 34:1485-90. [PMID: 1977366 PMCID: PMC171857 DOI: 10.1128/aac.34.8.1485] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A structural analog, 5'-([(Z)-4-amino-2-butenyl]methylamino)-5'-deoxy adenosine (MDL 73811), of decarboxy S-adenosyl-L-methionine, the product of the reaction catalyzed by S-adenosyl-L-methionine (AdoMet) decarboxylase (DC), was found to inhibit Trypanosoma brucei brucei AdoMet DC. The inhibition was time dependent (tau 50, 0.3 min), exhibited pseudo-first-order kinetics (Ki, 1.5 microM), and was apparently irreversible. The natural substrate of the reaction, AdoMet, protected the enzyme from inactivation, suggesting that MDL 73811 was directed at the enzyme active site and was probably catalytically activated. Administration of MDL 73811 to T. b. brucei-infected rats resulted in rapid inhibition of AdoMet DC activity, a decrease in spermidine, and an increase in putrescine in the trypanosomes isolated from treated rats. Treatment of T. b. brucei-infected mice with MDL 73811 (20 mg/kg of body weight intraperitoneally twice daily for 4 days) resulted in cures of the trypanosome infections. Additionally, drug-resistant T. brucei rhodesiense infections in mice were cured by either a combination of MDL 73811 (50 mg/kg intraperitoneally three times per day for 5 days) and relatively low oral doses of alpha-difluoromethylornithine or MDL 73811 (50 mg/kg per day for 7 days) administered alone in implanted miniosmotic pumps. These data suggest that MDL 73811 and, perhaps, other inhibitors of AdoMet DC have potential for therapeutic use in various forms of African trypanosomiasis.
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29
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Onyeyili PA, Anika SM. Chemotherapy of T b brucei infection: Use of DFMO, diminazene aceturate, alone and in combination. J Small Anim Pract 1989. [PMCID: PMC7166847 DOI: 10.1111/j.1748-5827.1989.tb01621.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The therapeutic activity of diminazene aceturate, difluoromethylornithine (DFMO) and a combination of the two agents was investigated in experimental Trypanosoma brucei brucei infections in mongrel dogs. The criteria used in the assessment of the trypanocidal effect of these compounds included the examination of the blood for the parasite, as well as clinical and haematological changes at intervals following treatment. Diminazene aceturate (7 mg/kg intramuscularly), DFMO (300 mg/kg/day orally in three divided doses for six days) and the combination of diminazene aceturate (7 mg/kg intramuscularly) and DFMO (300 mg/kg/day orally for six days) produced an intermittent aparasitemia in the dogs. Relapse infection occurred in all the three groups, but the period of aparasitemia produced by the combination of the agents was longest. The packed cell volume, haemoglobin concentration and red cell count values decreased after the dogs were inoculated with the parasite. The values improved slightly following the treatments with the agents or their combination. The total white blood cell counts in the infected dogs indicated leucocytosis, but this improved with drug treatment.
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30
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Van Bogaert I, Haemers A. Eflornithine. A new drug in the treatment of sleeping sickness. PHARMACEUTISCH WEEKBLAD. SCIENTIFIC EDITION 1989; 11:69-75. [PMID: 2505225 DOI: 10.1007/bf02110252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Eflornithine (alpha-difluoromethylornithine; DFMO) is a recently developed drug against African trypanosomiasis (sleeping sickness). After a short description of trypanosomiasis and the current treatment, the mechanism of action of eflornithine is discussed, some clinical data is given and attention is paid to recently discovered analogues of eflornithine. Some examples of combination therapy with eflornithine and possible applications are mentioned.
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Affiliation(s)
- I Van Bogaert
- Department of Pharmaceutical Sciences, University of Antwerp, Belgium
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31
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Balaña-Fouce R, Ordóñez D, Alunda JM. Putrescine transport system in Leishmania infantum promastigotes. Mol Biochem Parasitol 1989; 35:43-50. [PMID: 2503722 DOI: 10.1016/0166-6851(89)90140-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A transport system for putrescine in Leishmania infantum (= L. donovani infantum) promastigotes has been identified and characterized by measuring the uptake of radioactively labelled putrescine. Putrescine uptake was time- and temperature-dependent without any accumulation taking place at 0 degrees C. Uptake of putrescine was maximal at pH values near neutrality. Putrescine uptake showed an apparent Km = 1.08 +/- 0.12 microM and a Vmax = 1.74 + 0.62 pmol min-1 (10(6) cells)-1. The effect of metabolic poisons and uncoupling agents suggests that the putrescine uptake was energy-dependent. The transport system seemed to be highly specific for putrescine as neither aminoacids nor related compounds tested showed any competition with putrescine uptake. The trypanocide Berenil inhibited almost completely the putrescine uptake with non-competitive kinetics and a value of Ki = 43 microM.
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Affiliation(s)
- R Balaña-Fouce
- Departamento de Farmacología y Toxicología, Facultad de Veterinaria, Universidad Complutense de Madrid, Spain
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32
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Sharma V, Visen PK, Katiyar JC, Wittich RM, Walter RD, Ghatak S, Shukla OP. Polyamine metabolism in Ancylostoma ceylanicum and Nippostrongylus brasiliensis. Int J Parasitol 1989; 19:191-8. [PMID: 2722392 DOI: 10.1016/0020-7519(89)90007-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Spermidine was detected as the major polyamine of Ancylostoma ceylanicum as well as Nippostrongylus brasiliensis. Spermine was present in lower amounts whereas the level of putrescine was even less. S-Adenosylmethionine decarboxylase, a rate-limiting enzyme in the biosynthetic pathway of polyamines, was demonstrated at low levels in both parasites. Decarboxylation of lysine and arginine was absent or negligible and that of ornithine questionable, as the enzyme activity was not inhibited by alpha-difluoromethylornithine while RMI 71,645, an irreversible inhibitor of ornithine aminotransferase, strongly inhibited the liberation of CO2 from ornithine. High activity of ornithine aminotransferase was observed in both the parasites and may interfere with the assay for ornithine decarboxylase. Adults of A. ceylanicum were found to rapidly take up spermidine and spermine from incubation medium while uptake of putrescine was very low. These results indicate that hookworms depend on uptake and interconversion rather than de novo synthesis for their polyamine requirement.
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33
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Singh RP, Saxena JK, Ghatak S, Shukla OP, Wittich RM, Walter RD. Polyamine metabolism in Setaria cervi, the bovine filarial worm. Parasitol Res 1989; 75:311-5. [PMID: 2704725 DOI: 10.1007/bf00931816] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Spermine and spermidine were found to be the principal polyamines in the bovine filarial parasite Setaria cervi, whereas putrescine was observed in very low amounts. Studies conducted on the enzymes of polyamine biosynthesis revealed low activity for S-adenosyl-methionine decarboxylase, questionable and negligible activities for the decarboxylation of ornithine and arginine, and appreciable activity for ornithine aminotransferase. Uptake studies with radiolabeled putrescine, spermidine and spermine showed that these amines are rapidly taken up from the medium by an active uptake process. The uptake was temperature-sensitive and abolished at 0-4 degrees C. The questionable presence of biosynthetic enzymes such as ornithine and arginine decarboxylase and, on the other hand, an effective uptake mechanism indicate that the parasite may depend on the host for its polyamine requirement, thereby indicating a possible target for chemotherapy.
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Affiliation(s)
- R P Singh
- Biochemistry Division, Central Drug Research Institute, Chattar Manzil, Lucknow, India
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34
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Pfaller M, Riley J, Gerarden T. Polyamine depletion and growth inhibition inCandida albicansandCandida tropicalisby α-difluoromethylornithine and cyclohexylamine. Med Mycol 1988. [DOI: 10.1080/02681218880000171] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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35
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Kim BG, Sobota A, Bitonti AJ, McCann PP, Byers TJ. Polyamine metabolism in Acanthamoeba: polyamine content and synthesis of ornithine, putrescine, and diaminopropane. THE JOURNAL OF PROTOZOOLOGY 1987; 34:278-84. [PMID: 3656216 DOI: 10.1111/j.1550-7408.1987.tb03175.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Five polyamines which could be separated by high performance liquid chromatography were found in Acanthamoeba castellanii (strain Neff). These included in order of decreasing abundance: 1,3-diaminopropane, spermidine, spermine, norspermidine, and putrescine. Only diaminopropane and norspermidine had been found previously. Spermine was present in cultures grown in broth, but not in defined medium. Radioactive substrates were used to establish that putrescine was synthesized by decarboxylation of ornithine, ornithine was synthesized from arginine or citrulline, and diaminopropane was synthesized from spermidine. The presence of ornithine decarboxylase (EC 4.1.1.17), arginase (EC 3.5.3.1), and urease (EC 3.5.1.5) and the absence of arginine decarboxylase (EC 4.1.1.19) were established. A scheme for polyamine biosynthesis in A. castellanii is proposed.
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Affiliation(s)
- B G Kim
- Department of Microbiology, Ohio State University, Columbus 43210
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36
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Tietze KJ, Gaska JA, Cosgrove EM. Thrombocytopenia and vomiting due to difluoromethylornithine. DRUG INTELLIGENCE & CLINICAL PHARMACY 1987; 21:627-30. [PMID: 3111810 DOI: 10.1177/1060028087021007-812] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A 32-year-old Haitian male with acquired immunodeficiency syndrome presented with complications of Isospora belli enteritis. Therapy with the investigational drug difluoromethylornithine was initiated. Severe thrombocytopenia, nausea, and vomiting developed during intravenous drug therapy and recurred upon rechallenge with low-dose oral difluoromethylornithine. Therapy was discontinued because of these severe adverse effects.
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37
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Kierszenbaum F, Wirth JJ, McCann PP, Sjoerdsma A. Arginine decarboxylase inhibitors reduce the capacity of Trypanosoma cruzi to infect and multiply in mammalian host cells. Proc Natl Acad Sci U S A 1987; 84:4278-82. [PMID: 3295879 PMCID: PMC305068 DOI: 10.1073/pnas.84.12.4278] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The capacity of blood (trypomastigote) forms of Trypanosoma cruzi to infect mouse peritoneal macrophages or rat heart myoblasts in vitro was inhibited by treatment of the trypomastigotes with DL-alpha-difluoromethylarginine (F2Me Arg), monofluoromethylagmatine, or (E)-alpha-monofluoromethyl-3-4-dehydroarginine--all irreversible inhibitors of arginine decarboxylase. Similar results were obtained when F2MeArg-treated parasites were incubated with rat heart myoblasts. The inhibitory effects were characterized by marked reductions in both the proportion of infected cells and the number of parasites per 100 host cells. The concentrations of the arginine decarboxylase inhibitors that affected infectivity had no detectable effect on either the concentration or motility of the parasite and, therefore, could not have affected the collision frequency. F2MeArg appeared to inhibit the ability of T. cruzi to penetrate the host cells since the drug had no significant effect on the extent of parasite binding to the surface of the host cells. The inhibitory effect of F2MeArg was markedly reduced or abrogated in the presence of either agmatine or putrescine, as would have been expected if F2MeArg acted by inhibiting arginine decarboxylase. Addition of F2MeArg to macrophage or myoblast cultures immediately after infection or at a time when virtually all of the intracellular parasites had transformed into the multiplicative amastigote form, resulted in a markedly reduced parasite growth rate. This effect was also prevented by exogenous agmatine. These results indicate the importance of polyamines and polyamine biosynthesis in the following two important functions of T. cruzi: invasion of host cells and intracellular multiplication. Furthermore, concentrations of the inhibitors tested that affected the parasite did not alter the viability of the host cells, the cellular density of the cultures, or the ability of uninfected myoblasts to grow. Thus, arginine decarboxylase inhibitors may have a potential application in chemotherapy against T. cruzi infection.
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38
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Fairlamb AH, Henderson GB, Bacchi CJ, Cerami A. In vivo effects of difluoromethylornithine on trypanothione and polyamine levels in bloodstream forms of Trypanosoma brucei. Mol Biochem Parasitol 1987; 24:185-91. [PMID: 3114634 DOI: 10.1016/0166-6851(87)90105-8] [Citation(s) in RCA: 130] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The effect of D,L-alpha-difluoromethylornithine (DFMO) on thiol and polyamine levels in Trypanosoma brucei was investigated by isolating trypanosomes from infected rats treated with DFMO for 12-48 h. Concentrations of thiols, polyamines and other amino-compounds were measured by an automated high-performance liquid chromatography method. The levels of DFMO in rat plasma (0.02-1.34 mM) is similar to that found in the parasites (0.27-0.99 mM), concentrations which exceed the Ki of DFMO for T. brucei ornithine decarboxylase. Treatment with DFMO increases intracellular levels of ornithine, S-adenosylmethionine and decarboxylated S-adenosylmethionine and decreases putrescine and spermidine. Putrescine is undetectable after 12 h treatment with DFMO and after 48 h spermidine is decreased by 76%. By 48 h, the spermidine-glutathione conjugates glutathionylspermidine and dihydrotrypanothione (bis(glutathionyl)spermidine) are also decreased by 41 and 66%, respectively. In contrast, levels of glutathione show a slight increase. These changes in metabolite levels are consistent with the biosynthetic pathway proposed for Crithidia fasciculata, where trypanothione is synthesized from spermidine and glutathione via the intermediates N1- and N8-glutathionyl-spermidine. Trypanothione is thought to have two important roles in trypanosomatid metabolism: the maintenance of intracellular thiols in the correct redox state and in the removal of hydrogen peroxide and other hydroperoxides. Thus, it is proposed that depletion of this metabolite may be an important contributory factor to the selective toxic effect of DFMO, particularly in its synergistic effect with other trypanocidal drugs.
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Gupta S, Shukla OP, Walter RD. Putrescine-activated S-adenosylmethionine decarboxylase from Acanthamoeba culbertsoni. Mol Biochem Parasitol 1987; 23:247-52. [PMID: 3600699 DOI: 10.1016/0166-6851(87)90031-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Acanthamoeba culbertsoni, the free living pathogenic amoeba responsible for fatal meningoencephalitis, contains an S-adenosylmethionine decarboxylase (EC 4.1.1.50) which is strongly activated by putrescine and to a lesser extent by cadaverine; spermidine, spermine, diaminopropane and 1,6-diaminohexane are inactive. Methylglyoxal bis-(guanylhydrazone) competitively inhibited the enzyme with a Ki value of 123 microM. The enzyme was strongly inhibited by berenil (Ki = 0.5 microM) and to a lesser extent by pentamidine. The putrescine-activated enzyme is inhibited by MgCl2. The apparent molecular weight of 110,000 and its enzymatic properties indicate that the enzyme has characteristics intermediate between the bacterial and eukaryotic S-adenosylmethionine decarboxylases.
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Pfaller MA, Gerarden T, Riley J. Growth inhibition of pathogenic yeast isolates by alpha-difluoromethylornithine: an inhibition of ornithine decarboxylase. Mycopathologia 1987; 98:3-8. [PMID: 3108666 DOI: 10.1007/bf00431009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A large body of evidence exists suggesting that polyamines can play essential roles in cellular growth and differentiation. We examined the ability of alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, the major rate-limiting enzyme in polyamine biosynthesis, to inhibit the growth of Candida albicans, C. tropicalis, and C. parapsilosis. Substantial growth-inhibition was observed for all three species at DFMO concentrations ranging from 1 to 100 mM. C. tropicalis was significantly more susceptible to DFMO than C. albicans or C. parapsilosis. Depletion of cellular polyamine pools was seen in all 3 species following exposure to DFMO and polyamine depletion enhanced the susceptibility of the organisms to DFMO. The action of DFMO was specifically antagonized by exogenous polyamines. These data suggest that polyamines are important in the growth of Candida spp. and that inhibitors of polyamine biosynthesis may be useful as antifungal agents.
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Taelman H, Schechter PJ, Marcelis L, Sonnet J, Kazyumba G, Dasnoy J, Haegele KD, Sjoerdsma A, Wery M. Difluoromethylornithine, an effective new treatment of Gambian trypanosomiasis. Results in five patients. Am J Med 1987; 82:607-14. [PMID: 3103442 DOI: 10.1016/0002-9343(87)90107-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Recent studies have shown DL-alpha-difluoromethylornithine (eflornithine), an inhibitor of polyamine biosynthesis, to be curative in various Trypanosoma species infections of laboratory animals. Five patients are described with Gambian trypanosomiasis treated in Belgium with difluoromethylornithine, using various intravenous and oral dosage schedules. Three patients had late-stage and two had early-stage disease. Difluoromethylornithine treatment was associated with clearing of parasites from blood within one to four days, a trend towards normalization of all altered biologic values associated with the disease, and marked amelioration of clinical symptoms. Side effects of difluoromethylornithine, including loose stools in three patients and both anemia, and a decrease in auditory acuity in one patient, were mild, transient, and never required interruption of drug treatment. The presence of difluoromethylornithine in cerebrospinal fluid, determined in three patients, demonstrated that difluoromethylornithine penetrates into the central nervous system. In three patients, follow-up of at least 24 months after treatment demonstrated a continued healthy state without evidence of relapse. These promising, albeit preliminary, results of difluoromethylornithine therapy, even in patients with central nervous system involvement, indicate that extended clinical trials are warranted to determine the optimal dosage regimen in patients with early- and late-stage disease.
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San-Martín Núñez B, Alunda JM, Balaña-Fouce R, Ordóñez Escudero D. Effects of methylglyoxal bis(guanylhydrazone) and two phenylated analogues on S-adenosylmethionine decarboxylase activity from Eimeria stiedai (Apicomplexa). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1987; 87:863-6. [PMID: 3665433 DOI: 10.1016/0305-0491(87)90403-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
1. Activity of S-adenosylmethionine decarboxylase, one of the rate-limiting enzymes of polyamine biosynthesis, was determined in oocysts of Eimeria stiedai, a coccidian parasite of the rabbit. 2. Several properties of the enzyme were compared to the mammalian enzyme. It showed considerably less substrate affinity than the analog enzyme from the rabbit. 3. The E. stiedai enzyme showed a low sensitivity to methylglyoxal bis(guanylhydrazone), a frequently used inhibitor of the enzyme in mammals, and two phenylated derivatives. 4. Results with the inhibitors are discussed in view of their potential use in chemotherapy.
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Affiliation(s)
- B San-Martín Núñez
- Departamento de Toxicología y Farmacología, Facultad de Veterinaria Universidad Complutense de Madrid, Spain
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Schirmer RH, Schöllhammer T, Eisenbrand G, Krauth-Siegel RL. Oxidative stress as a defense mechanism against parasitic infections. FREE RADICAL RESEARCH COMMUNICATIONS 1987; 3:3-12. [PMID: 3508442 DOI: 10.3109/10715768709069763] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Many parasites--including the causative agents of malaria, Chagas' disease and schistosomiasis--are more susceptible to reactive oxygen species (ROS) than their hosts are. This is manifested by one or more of the following criteria: 1. Susceptibility of the parasite to ROS in vitro; 2. macrophage-based defense mechanisms against the parasite in vivo; 3. successful therapy using agents which lead to oxidative stress; 4. selection advantage (with respect to parasite infections) of human populations whose antioxidant capacity is impaired by a gene defect or by strong oxidants in their staple food. Our laboratory is involved in developing inhibitors against antioxidant enzymes thus mimicking natural experiments. Since glutathione reductase is a protein of known atomic structure the methods of drug design by receptor fit (DDRF) can be applied for this enzyme. Another promising target enzyme is trypanothione reductase which was found so far only in trypanosomatids, and specifically, not in their hosts. Consequently the trypanothione pathway may be a general target in the design of drugs against diseases caused by trypanosomes and leishmanias.
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Affiliation(s)
- R H Schirmer
- Institut für Biochemie II, Universität Heidelberg, FRG
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44
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Ferrante A, Abell T, Robinson B, Lederer E. Effects of sinefungin and difluoromethylornithine on pathogenic free-living amoebae in vitro. FEMS Microbiol Lett 1987. [DOI: 10.1111/j.1574-6968.1987.tb01984.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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46
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Osuna A, Gamarro F, Castanys S, Ruiz-Perez LM. Inhibition of lysosomal fusion by Trypanosoma cruzi in peritoneal macrophages. Int J Parasitol 1986; 16:629-32. [PMID: 3542866 DOI: 10.1016/0020-7519(86)90031-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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47
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Bitonti AJ, Dumont JA, McCann PP. Characterization of Trypanosoma brucei brucei S-adenosyl-L-methionine decarboxylase and its inhibition by Berenil, pentamidine and methylglyoxal bis(guanylhydrazone). Biochem J 1986; 237:685-9. [PMID: 3800910 PMCID: PMC1147045 DOI: 10.1042/bj2370685] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Trypanosoma brucei brucei S-adenosyl-L-methionine (AdoMet) decarboxylase was found to be relatively insensitive to activation by putrescine as compared with the mammalian enzyme, being stimulated by only 50% over a 10,000-fold range of putrescine concentrations. The enzyme was not stimulated by up to 10 mM-Mg2+. The Km for AdoMet was 30 microM, similar to that of other eukaryotic AdoMet decarboxylases. T.b. brucei AdoMet decarboxylase activity was apparently irreversibly inhibited in vitro by Berenil and reversibly by pentamidine and methylglyoxal bis(guanylhydrazone). Berenil also inhibited trypanosomal AdoMet decarboxylase by 70% within 4 h after administration to infected rats and markedly increased the concentration of putrescine in trypanosomes that were exposed to the drug in vivo. Spermidine and spermine blocked the curative effect of Berenil on model mouse T.b. brucei infections. This effect of the polyamines was probably not due to reversal of Berenil's inhibitory effects on the AdoMet decarboxylase.
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Abstract
In spite of the continuing need for new and improved anti-protozoal drugs for use in man, a considerable contraction of industrially based research on anti-protozoal drugs has occurred in recent years. Newton (1983) reviewed the reasons for this decline and presented a compelling argument that fundamental research on the biology of the parasites is essential for the discovery of leads for the development of a new generation of drugs – a rational chemotherapy. The rapid advance in knowledge of the biochemistry of parasitic protozoa which has occurred in recent years has provided a number of potential leads to new drug development and has permitted a greater understanding of the mode of action of many current drugs. The account of these advances which follows is necessarily selective and relates to protozoan parasites of man.
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Fairlamb AH, Blackburn P, Ulrich P, Chait BT, Cerami A. Trypanothione: a novel bis(glutathionyl)spermidine cofactor for glutathione reductase in trypanosomatids. Science 1985; 227:1485-7. [PMID: 3883489 DOI: 10.1126/science.3883489] [Citation(s) in RCA: 515] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Glutathione reductase from trypanosomes and leishmanias, unlike glutathione reductase from other organisms, requires an unusual low molecular weight cofactor for activity. The cofactor was purified from the insect trypanosomatid Crithidia fasciculata and identified as a novel glutathione-spermidine conjugate, N1,N8-bis(L-gamma-glutamyl-L-hemicystinyl-glycyl)spermidine, for which the trivial name trypanothione is proposed. This discovery may open a new chemotherapeutic approach to trypanosomiasis and leishmaniasis.
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50
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Russell DH. Ornithine decarboxylase: a key regulatory enzyme in normal and neoplastic growth. Drug Metab Rev 1985; 16:1-88. [PMID: 3905315 DOI: 10.3109/03602538508991430] [Citation(s) in RCA: 178] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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