1
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Aldfer MM, Hulpia F, van Calenbergh S, De Koning HP. Mapping the transporter-substrate interactions of the Trypanosoma cruzi NB1 nucleobase transporter reveals the basis for its high affinity and selectivity for hypoxanthine and guanine and lack of nucleoside uptake. Mol Biochem Parasitol 2024; 258:111616. [PMID: 38401850 DOI: 10.1016/j.molbiopara.2024.111616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/19/2024] [Accepted: 02/20/2024] [Indexed: 02/26/2024]
Abstract
Trypanosoma cruzi is a protozoan parasite and the etiological agent of Chagas disease, a debilitating and sometimes fatal disease that continues to spread to new areas. Yet, Chagas disease is still only treated with two related nitro compounds that are insufficiently effective and cause severe side effects. Nucleotide metabolism is one of the known vulnerabilities of T. cruzi, as they are auxotrophic for purines, and nucleoside analogues have been shown to have genuine promise against this parasite in vitro and in vivo. Since purine antimetabolites require efficient uptake through transporters, we here report a detailed characterisation of the T. cruzi NB1 nucleobase transporter with the aim of elucidating the interactions between TcrNB1 and its substrates and finding the positions that can be altered in the design of novel antimetabolites without losing transportability. Systematically determining the inhibition constants (Ki) of purine analogues for TcrNB1 yielded their Gibbs free energy of interaction, ΔG0. Pairwise comparisons of substrate (hypoxanthine, guanine, adenine) and analogues allowed us to determine that optimal binding affinity by TcrNB1 requires interactions with all four nitrogen residues of the purine ring, with N1 and N9, in protonation state, functioning as presumed hydrogen bond donors and unprotonated N3 and N7 as hydrogen bond acceptors. This is the same interaction pattern as we previously described for the main nucleobase transporters of Trypanosoma brucei spp. and Leishmania major and makes it the first of the ENT-family genes that is functionally as well as genetically conserved between the three main kinetoplast pathogens.
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Affiliation(s)
- Mustafa M Aldfer
- School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, University of Glasgow, GlasgowG12 8TA, UK
| | - Fabian Hulpia
- Laboratory for Medicinal Chemistry (Campus Heymans), Ghent University, Ottergemsesteenweg 460, 9000 Gent, Belgium
| | - Serge van Calenbergh
- Laboratory for Medicinal Chemistry (Campus Heymans), Ghent University, Ottergemsesteenweg 460, 9000 Gent, Belgium
| | - Harry P De Koning
- School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, University of Glasgow, GlasgowG12 8TA, UK.
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2
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Elati HAA, Goerner AL, Martorelli Di Genova B, Sheiner L, de Koning HP. Pyrimidine salvage in Toxoplasma gondii as a target for new treatment. Front Cell Infect Microbiol 2023; 13:1320160. [PMID: 38162577 PMCID: PMC10755004 DOI: 10.3389/fcimb.2023.1320160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 12/01/2023] [Indexed: 01/03/2024] Open
Abstract
Toxoplasmosis is a common protozoan infection that can have severe outcomes in the immunocompromised and during pregnancy, but treatment options are limited. Recently, nucleotide metabolism has received much attention as a target for new antiprotozoal agents and here we focus on pyrimidine salvage by Toxoplasma gondii as a drug target. Whereas uptake of [3H]-cytidine and particularly [3H]-thymidine was at most marginal, [3H]-uracil and [3H]-uridine were readily taken up. Kinetic analysis of uridine uptake was consistent with a single transporter with a Km of 3.3 ± 0.8 µM, which was inhibited by uracil with high affinity (Ki = 1.15 ± 0.07 µM) but not by thymidine or 5-methyluridine, showing that the 5-Me group is incompatible with uptake by T. gondii. Conversely, [3H]-uracil transport displayed a Km of 2.05 ± 0.40 µM, not significantly different from the uracil Ki on uridine transport, and was inhibited by uridine with a Ki of 2.44 ± 0.59 µM, also not significantly different from the experimental uridine Km. The reciprocal, complete inhibition, displaying Hill slopes of approximately -1, strongly suggest that uridine and uracil share a single transporter with similarly high affinity for both, and we designate it uridine/uracil transporter 1 (TgUUT1). While TgUUT1 excludes 5-methyl substitutions, the smaller 5F substitution was tolerated, as 5F-uracil inhibited uptake of [3H]-uracil with a Ki of 6.80 ± 2.12 µM (P > 0.05 compared to uracil Km). Indeed, we found that 5F-Uridine, 5F-uracil and 5F,2'-deoxyuridine were all potent antimetabolites against T. gondii with EC50 values well below that of the current first line treatment, sulfadiazine. In vivo evaluation also showed that 5F-uracil and 5F,2'-deoxyuridine were similarly effective as sulfadiazine against acute toxoplasmosis. Our preliminary conclusion is that TgUUT1 mediates potential new anti-toxoplasmosis drugs with activity superior to the current treatment.
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Affiliation(s)
- Hamza A. A. Elati
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Department of Pharmacology and Toxicology, Pharmacy College, University of Elmergib, Al Khums, Libya
| | - Amber L. Goerner
- Larner College of Medicine at The University of Vermont, Department of Microbiology and Molecular Genetics, Burlington, VT, United States
| | - Bruno Martorelli Di Genova
- Larner College of Medicine at The University of Vermont, Department of Microbiology and Molecular Genetics, Burlington, VT, United States
| | - Lilach Sheiner
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Harry P. de Koning
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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3
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Nué-Martinez JJ, Cisneros D, Moreno-Blázquez MD, Fonseca-Berzal C, Manzano JI, Kraeutler D, Ungogo MA, Aloraini MA, Elati HAA, Ibáñez-Escribano A, Lagartera L, Herraiz T, Gamarro F, de Koning HP, Gómez-Barrio A, Dardonville C. Synthesis and Biophysical and Biological Studies of N-Phenylbenzamide Derivatives Targeting Kinetoplastid Parasites. J Med Chem 2023; 66:13452-13480. [PMID: 37729094 PMCID: PMC10578353 DOI: 10.1021/acs.jmedchem.3c00697] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Indexed: 09/22/2023]
Abstract
The AT-rich mitochondrial DNA (kDNA) of trypanosomatid parasites is a target of DNA minor groove binders. We report the synthesis, antiprotozoal screening, and SAR studies of three series of analogues of the known antiprotozoal kDNA binder 2-((4-(4-((4,5-dihydro-1H-imidazol-3-ium-2-yl)amino)benzamido)phenyl)amino)-4,5-dihydro-1H-imidazol-3-ium (1a). Bis(2-aminoimidazolines) (1) and bis(2-aminobenzimidazoles) (2) showed micromolar range activity against Trypanosoma brucei, whereas bisarylimidamides (3) were submicromolar inhibitors of T. brucei, Trypanosoma cruzi, and Leishmania donovani. None of the compounds showed relevant activity against the urogenital, nonkinetoplastid parasite Trichomonas vaginalis. We show that series 1 and 3 bind strongly and selectively to the minor groove of AT DNA, whereas series 2 also binds by intercalation. The measured pKa indicated different ionization states at pH 7.4, which correlated with the DNA binding affinities (ΔTm) for series 2 and 3. Compound 3a, which was active and selective against the three parasites and displayed adequate metabolic stability, is a fine candidate for in vivo studies.
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Affiliation(s)
- J. Jonathan Nué-Martinez
- Instituto
de Química Médica, IQM−CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
- PhD
Programme in Medicinal Chemistry, Doctoral School, Universidad Complutense de Madrid (UCM), 28040 Madrid, Spain
| | - David Cisneros
- Instituto
de Química Médica, IQM−CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
- PhD
Programme in Medicinal Chemistry, Doctoral School, Universidad Complutense de Madrid (UCM), 28040 Madrid, Spain
| | | | - Cristina Fonseca-Berzal
- Departamento
de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain
| | - José Ignacio Manzano
- Instituto
de Parasitología y Biomedicina “Löpez Neyra”,
IPBLN-CSIC, Parque Tecnolögico
de Ciencias de la Salud, 18016 Granada, Spain
| | - Damien Kraeutler
- Instituto
de Química Médica, IQM−CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Marzuq A. Ungogo
- Institute
of Infection, Immunity and Inflammation, College of Medical, Veterinary
and Life Sciences, University of Glasgow, G12 8TA Glasgow, U.K.
| | - Maha A. Aloraini
- Institute
of Infection, Immunity and Inflammation, College of Medical, Veterinary
and Life Sciences, University of Glasgow, G12 8TA Glasgow, U.K.
| | - Hamza A. A. Elati
- Institute
of Infection, Immunity and Inflammation, College of Medical, Veterinary
and Life Sciences, University of Glasgow, G12 8TA Glasgow, U.K.
| | - Alexandra Ibáñez-Escribano
- Departamento
de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain
| | - Laura Lagartera
- Instituto
de Química Médica, IQM−CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Tomás Herraiz
- Instituto
de Ciencia y Tecnología de Alimentos y Nutrición, ICTAN−CSIC, José Antonio Novais 10, Ciudad
Universitaria, 28040 Madrid, Spain
| | - Francisco Gamarro
- Instituto
de Parasitología y Biomedicina “Löpez Neyra”,
IPBLN-CSIC, Parque Tecnolögico
de Ciencias de la Salud, 18016 Granada, Spain
| | - Harry P. de Koning
- Institute
of Infection, Immunity and Inflammation, College of Medical, Veterinary
and Life Sciences, University of Glasgow, G12 8TA Glasgow, U.K.
| | - Alicia Gómez-Barrio
- Departamento
de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain
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Ungogo MA, Aldfer MM, Natto MJ, Zhuang H, Chisholm R, Walsh K, McGee M, Ilbeigi K, Asseri JI, Burchmore RJS, Caljon G, Van Calenbergh S, De Koning HP. Cloning and Characterization of Trypanosoma congolense and T. vivax Nucleoside Transporters Reveal the Potential of P1-Type Carriers for the Discovery of Broad-Spectrum Nucleoside-Based Therapeutics against Animal African Trypanosomiasis. Int J Mol Sci 2023; 24:ijms24043144. [PMID: 36834557 PMCID: PMC9960827 DOI: 10.3390/ijms24043144] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/09/2023] Open
Abstract
African Animal Trypanosomiasis (AAT), caused predominantly by Trypanosoma brucei brucei, T. vivax and T. congolense, is a fatal livestock disease throughout Sub-Saharan Africa. Treatment options are very limited and threatened by resistance. Tubercidin (7-deazaadenosine) analogs have shown activity against individual parasites but viable chemotherapy must be active against all three species. Divergence in sensitivity to nucleoside antimetabolites could be caused by differences in nucleoside transporters. Having previously characterized the T. brucei nucleoside carriers, we here report the functional expression and characterization of the main adenosine transporters of T. vivax (TvxNT3) and T. congolense (TcoAT1/NT10), in a Leishmania mexicana cell line ('SUPKO') lacking adenosine uptake. Both carriers were similar to the T. brucei P1-type transporters and bind adenosine mostly through interactions with N3, N7 and 3'-OH. Expression of TvxNT3 and TcoAT1 sensitized SUPKO cells to various 7-substituted tubercidins and other nucleoside analogs although tubercidin itself is a poor substrate for P1-type transporters. Individual nucleoside EC50s were similar for T. b. brucei, T. congolense, T. evansi and T. equiperdum but correlated less well with T. vivax. However, multiple nucleosides including 7-halogentubercidines displayed pEC50>7 for all species and, based on transporter and anti-parasite SAR analyses, we conclude that nucleoside chemotherapy for AAT is viable.
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Affiliation(s)
- Marzuq A. Ungogo
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
- Department of Veterinary Pharmacology and Toxicology, Ahmadu Bello University, Zaria 810107, Kaduna State, Nigeria
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
| | - Mustafa M. Aldfer
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Manal J. Natto
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Hainan Zhuang
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Robyn Chisholm
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Katy Walsh
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - MarieClaire McGee
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Kayhan Ilbeigi
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, B-2610 Wilrijk, Belgium
| | - Jamal Ibrahim Asseri
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Richard J. S. Burchmore
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Guy Caljon
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, B-2610 Wilrijk, Belgium
| | - Serge Van Calenbergh
- Laboratory for Medicinal Chemistry (Campus Heymans), Ghent University, B-9000 Gent, Belgium
| | - Harry P. De Koning
- School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
- Correspondence:
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5
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The Trypanosoma cruzi TcrNT2 Nucleoside Transporter Is a Conduit for the Uptake of 5-F-2'-Deoxyuridine and Tubercidin Analogues. Molecules 2022; 27:molecules27228045. [PMID: 36432150 PMCID: PMC9693223 DOI: 10.3390/molecules27228045] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Among the scarce validated drug targets against Chagas disease (CD), caused by Trypanosoma cruzi, the parasite's nucleoside salvage system has recently attracted considerable attention. Although the trypanocidal activity of tubercidin (7-deazapurine) has long been known, the identification of a class of 7-substituted tubercidin analogs with potent in vitro and in vivo activity and much-enhanced selectivity has made nucleoside analogs among the most promising lead compounds against CD. Here, we investigate the recently identified TcrNT2 nucleoside transporter and its potential role in antimetabolite chemotherapy. TcrNT2, expressed in a Leishmania mexicana cell line lacking the NT1 nucleoside transporter locus, displayed very high selectivity and affinity for thymidine with a Km of 0.26 ± 0.05 µM. The selectivity was explained by interactions of 2-oxo, 4-oxo, 5-Me, 3'-hydroxy and 5'-hydroxy with the transporter binding pocket, whereas a hydroxy group at the 2' position was deleterious to binding. This made 5-halogenated 2'-deoxyuridine analogues good substrates but 5-F-2'-deoxyuridine displayed disappointing activity against T. cruzi trypomastigotes. By comparing the EC50 values of tubercidin and its 7-substituted analogues against L. mexicana Cas9, Cas9ΔNT1 and Cas9ΔNT1+TcrNT2 it was shown that TcrNT2 can take up tubercidin and, at a minimum, a subset of the analogs.
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6
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Nucleoside Transport and Nucleobase Uptake Null Mutants in Leishmania mexicana for the Routine Expression and Characterization of Purine and Pyrimidine Transporters. Int J Mol Sci 2022; 23:ijms23158139. [PMID: 35897714 PMCID: PMC9331716 DOI: 10.3390/ijms23158139] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/05/2022] [Accepted: 07/20/2022] [Indexed: 12/02/2022] Open
Abstract
The study of transporters is highly challenging, as they cannot be isolated or studied in suspension, requiring a cellular or vesicular system, and, when mediated by more than one carrier, difficult to interpret. Nucleoside analogues are important drug candidates, and all protozoan pathogens express multiple equilibrative nucleoside transporter (ENT) genes. We have therefore developed a system for the routine expression of nucleoside transporters, using CRISPR/cas9 to delete both copies of all three nucleoside transporters from Leishmania mexicana (ΔNT1.1/1.2/2 (SUPKO)). SUPKO grew at the same rate as the parental strain and displayed no apparent deficiencies, owing to the cells’ ability to synthesize pyrimidines, and the expression of the LmexNT3 purine nucleobase transporter. Nucleoside transport was barely measurable in SUPKO, but reintroduction of L. mexicana NT1.1, NT1.2, and NT2 restored uptake. Thus, SUPKO provides an ideal null background for the expression and characterization of single ENT transporter genes in isolation. Similarly, an LmexNT3-KO strain provides a null background for transport of purine nucleobases and was used for the functional characterization of T. cruzi NB2, which was determined to be adenine-specific. A 5-fluorouracil-resistant strain (Lmex5FURes) displayed null transport for uracil and 5FU, and was used to express the Aspergillus nidulans uracil transporter FurD.
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7
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Campagnaro GD, Elati HAA, Balaska S, Martin Abril ME, Natto MJ, Hulpia F, Lee K, Sheiner L, Van Calenbergh S, de Koning HP. A Toxoplasma gondii Oxopurine Transporter Binds Nucleobases and Nucleosides Using Different Binding Modes. Int J Mol Sci 2022; 23:ijms23020710. [PMID: 35054895 PMCID: PMC8776092 DOI: 10.3390/ijms23020710] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 12/13/2022] Open
Abstract
Toxoplasma gondii is unable to synthesize purines de novo, instead salvages them from its environment, inside the host cell, for which they need high affinity carriers. Here, we report the expression of a T. gondii Equilibrative Nucleoside Transporter, Tg244440, in a Trypanosoma brucei strain from which nucleobase transporters have been deleted. Tg244440 transported hypoxanthine and guanine with similar affinity (Km ~1 µM), while inosine and guanosine displayed Ki values of 4.05 and 3.30 µM, respectively. Low affinity was observed for adenosine, adenine, and pyrimidines, classifying Tg244440 as a high affinity oxopurine transporter. Purine analogues were used to probe the substrate-transporter binding interactions, culminating in quantitative models showing different binding modes for oxopurine bases, oxopurine nucleosides, and adenosine. Hypoxanthine and guanine interacted through protonated N1 and N9, and through unprotonated N3 and N7 of the purine ring, whereas inosine and guanosine mostly employed the ribose hydroxy groups for binding, in addition to N1H of the nucleobase. Conversely, the ribose moiety of adenosine barely made any contribution to binding. Tg244440 is the first gene identified to encode a high affinity oxopurine transporter in T. gondii and, to the best of our knowledge, the first purine transporter to employ different binding modes for nucleosides and nucleobases.
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Affiliation(s)
- Gustavo D. Campagnaro
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK; (G.D.C.); (H.A.A.E.); (S.B.); (M.E.M.A.); (M.J.N.); (K.L.); (L.S.)
| | - Hamza A. A. Elati
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK; (G.D.C.); (H.A.A.E.); (S.B.); (M.E.M.A.); (M.J.N.); (K.L.); (L.S.)
| | - Sofia Balaska
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK; (G.D.C.); (H.A.A.E.); (S.B.); (M.E.M.A.); (M.J.N.); (K.L.); (L.S.)
| | - Maria Esther Martin Abril
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK; (G.D.C.); (H.A.A.E.); (S.B.); (M.E.M.A.); (M.J.N.); (K.L.); (L.S.)
| | - Manal J. Natto
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK; (G.D.C.); (H.A.A.E.); (S.B.); (M.E.M.A.); (M.J.N.); (K.L.); (L.S.)
| | - Fabian Hulpia
- Laboratory for Medicinal Chemistry, Campus Heymans, Ghent University, Ottergemsesteenweg 460, B-9000 Gent, Belgium; (F.H.); (S.V.C.)
| | - Kelly Lee
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK; (G.D.C.); (H.A.A.E.); (S.B.); (M.E.M.A.); (M.J.N.); (K.L.); (L.S.)
| | - Lilach Sheiner
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK; (G.D.C.); (H.A.A.E.); (S.B.); (M.E.M.A.); (M.J.N.); (K.L.); (L.S.)
- Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Serge Van Calenbergh
- Laboratory for Medicinal Chemistry, Campus Heymans, Ghent University, Ottergemsesteenweg 460, B-9000 Gent, Belgium; (F.H.); (S.V.C.)
| | - Harry P. de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK; (G.D.C.); (H.A.A.E.); (S.B.); (M.E.M.A.); (M.J.N.); (K.L.); (L.S.)
- Correspondence: ; Tel.: +44-141-3303753
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8
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Natto MJ, Miyamoto Y, Munday JC, AlSiari TA, Al-Salabi MI, Quashie NB, Eze AA, Eckmann L, De Koning HP. Comprehensive characterization of purine and pyrimidine transport activities in Trichomonas vaginalis and functional cloning of a trichomonad nucleoside transporter. Mol Microbiol 2021; 116:1489-1511. [PMID: 34738285 PMCID: PMC8688338 DOI: 10.1111/mmi.14840] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/30/2021] [Accepted: 10/30/2021] [Indexed: 11/30/2022]
Abstract
Trichomoniasis is a common and widespread sexually-transmitted infection, caused by the protozoan parasite Trichomonas vaginalis. T. vaginalis lacks the biosynthetic pathways for purines and pyrimidines, making nucleoside metabolism a drug target. Here we report the first comprehensive investigation into purine and pyrimidine uptake by T. vaginalis. Multiple carriers were identified and characterized with regard to substrate selectivity and affinity. For nucleobases, a high-affinity adenine transporter, a possible guanine transporter and a low affinity uracil transporter were found. Nucleoside transporters included two high affinity adenosine/guanosine/uridine/cytidine transporters distinguished by different affinities to inosine, a lower affinity adenosine transporter, and a thymidine transporter. Nine Equilibrative Nucleoside Transporter (ENT) genes were identified in the T. vaginalis genome. All were expressed equally in metronidazole-resistant and -sensitive strains. Only TvagENT2 was significantly upregulated in the presence of extracellular purines; expression was not affected by co-culture with human cervical epithelial cells. All TvagENTs were cloned and separately expressed in Trypanosoma brucei. We identified the main broad specificity nucleoside carrier, with high affinity for uridine and cytidine as well as purine nucleosides including inosine, as TvagENT3. The in-depth characterization of purine and pyrimidine transporters provides a critical foundation for the development of new anti-trichomonal nucleoside analogues.
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Affiliation(s)
- Manal J. Natto
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Yukiko Miyamoto
- Department of Medicine, University of California, San Diego, La Jolla, California 92093, United States
| | - Jane C. Munday
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Tahani A. AlSiari
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Mohammed I. Al-Salabi
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Neils B. Quashie
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, University of Ghana
| | - Anthonius A. Eze
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Current affiliation: Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Nigeria, Enugu Campus, Enugu, Nigeria
| | - Lars Eckmann
- Department of Medicine, University of California, San Diego, La Jolla, California 92093, United States
| | - Harry P. De Koning
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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9
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Steketee PC, Dickie EA, Iremonger J, Crouch K, Paxton E, Jayaraman S, Alfituri OA, Awuah-Mensah G, Ritchie R, Schnaufer A, Rowan T, de Koning HP, Gadelha C, Wickstead B, Barrett MP, Morrison LJ. Divergent metabolism between Trypanosoma congolense and Trypanosoma brucei results in differential sensitivity to metabolic inhibition. PLoS Pathog 2021; 17:e1009734. [PMID: 34310651 PMCID: PMC8384185 DOI: 10.1371/journal.ppat.1009734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 08/24/2021] [Accepted: 06/21/2021] [Indexed: 11/18/2022] Open
Abstract
Animal African Trypanosomiasis (AAT) is a debilitating livestock disease prevalent across sub-Saharan Africa, a main cause of which is the protozoan parasite Trypanosoma congolense. In comparison to the well-studied T. brucei, there is a major paucity of knowledge regarding the biology of T. congolense. Here, we use a combination of omics technologies and novel genetic tools to characterise core metabolism in T. congolense mammalian-infective bloodstream-form parasites, and test whether metabolic differences compared to T. brucei impact upon sensitivity to metabolic inhibition. Like the bloodstream stage of T. brucei, glycolysis plays a major part in T. congolense energy metabolism. However, the rate of glucose uptake is significantly lower in bloodstream stage T. congolense, with cells remaining viable when cultured in concentrations as low as 2 mM. Instead of pyruvate, the primary glycolytic endpoints are succinate, malate and acetate. Transcriptomics analysis showed higher levels of transcripts associated with the mitochondrial pyruvate dehydrogenase complex, acetate generation, and the glycosomal succinate shunt in T. congolense, compared to T. brucei. Stable-isotope labelling of glucose enabled the comparison of carbon usage between T. brucei and T. congolense, highlighting differences in nucleotide and saturated fatty acid metabolism. To validate the metabolic similarities and differences, both species were treated with metabolic inhibitors, confirming that electron transport chain activity is not essential in T. congolense. However, the parasite exhibits increased sensitivity to inhibition of mitochondrial pyruvate import, compared to T. brucei. Strikingly, T. congolense exhibited significant resistance to inhibitors of fatty acid synthesis, including a 780-fold higher EC50 for the lipase and fatty acid synthase inhibitor Orlistat, compared to T. brucei. These data highlight that bloodstream form T. congolense diverges from T. brucei in key areas of metabolism, with several features that are intermediate between bloodstream- and insect-stage T. brucei. These results have implications for drug development, mechanisms of drug resistance and host-pathogen interactions.
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Affiliation(s)
- Pieter C Steketee
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Emily A Dickie
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - James Iremonger
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Kathryn Crouch
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Edith Paxton
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Siddharth Jayaraman
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Omar A Alfituri
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Ryan Ritchie
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Tim Rowan
- Global Alliance for Livestock Veterinary Medicines, Edinburgh, United Kingdom
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Catarina Gadelha
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Bill Wickstead
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Michael P Barrett
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom.,Glasgow Polyomics, University of Glasgow, Glasgow, United Kingdom
| | - Liam J Morrison
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
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10
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Yagüe-Capilla M, Castillo-Acosta VM, Bosch-Navarrete C, Ruiz-Pérez LM, González-Pacanowska D. A Mitochondrial Orthologue of the dNTP Triphosphohydrolase SAMHD1 Is Essential and Controls Pyrimidine Homeostasis in Trypanosoma brucei. ACS Infect Dis 2021; 7:318-332. [PMID: 33417760 DOI: 10.1021/acsinfecdis.0c00551] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The maintenance of deoxyribonucleotide triphosphate (dNTP) homeostasis through synthesis and degradation is critical for accurate genomic and mitochondrial DNA replication fidelity. Trypanosoma brucei makes use of both the salvage and de novo pathways for the provision of pyrimidine dNTPs. In this respect, the sterile α motif and histidine-aspartate domain-containing protein 1 (SAMHD1) appears to be the most relevant dNTPase controlling dNTP/deoxynucleoside homeostasis in mammalian cells. Here, we have characterized the role of a unique trypanosomal SAMHD1 orthologue denominated TbHD52. Our results show that TbHD52 is a mitochondrial enzyme essential in bloodstream forms of T. brucei. Knockout cells are pyrimidine auxotrophs that exhibit strong defects in genomic integrity, cell cycle progression, and nuclear DNA and kinetoplast segregation in the absence of extracellular thymidine. The lack of TbHD52 can be counteracted by the overexpression of human dCMP deaminase, an enzyme that is directly involved in dUMP formation yet absent in trypanosomes. Furthermore, the cellular dNTP quantification and metabolomic analysis of TbHD52 null mutants revealed perturbations in the nucleotide metabolism with a substantial accumulation of dCTP and cytosine-derived metabolites while dTTP formation was significantly reduced. We propose that this HD-domain-containing protein unique to kinetoplastids plays an essential role in pyrimidine dNTP homeostasis and contributes to the provision of deoxycytidine required for cellular dTTP biosynthesis.
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Affiliation(s)
- Miriam Yagüe-Capilla
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada) 18016, Spain
| | - Víctor M. Castillo-Acosta
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada) 18016, Spain
| | - Cristina Bosch-Navarrete
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada) 18016, Spain
| | - Luis Miguel Ruiz-Pérez
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada) 18016, Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada) 18016, Spain
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11
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Alenezi SS, Natto MJ, Igoli JO, Gray AI, Fearnley J, Fearnley H, de Koning HP, Watson DG. Novel flavanones with anti-trypanosomal activity isolated from Zambian and Tanzanian propolis samples. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 14:201-207. [PMID: 33160277 PMCID: PMC7649109 DOI: 10.1016/j.ijpddr.2020.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 12/20/2022]
Abstract
A bioassay-guided phytochemical investigation of propolis samples from Tanzania and Zambia that screened for activity against Trypanosoma brucei has led to the isolation of two novel flavanones with promising antitrypanosomal activity. The compounds were characterized based on their spectral and physical data and identified as 6-(1,1-dimethylallyl) pinocembrin and 5-hydroxy-4″,4″-dimethyl-5″-methyl-5″-H-dihydrofuranol [2″,3″,6,7] flavanone. The two compounds, together with the propolis extracts and fractions, were assayed against a standard drug-sensitive strain of T. b. brucei (s427 wild-type), multi-drug resistant-resistant T. b. brucei (B48), drug-sensitive T. congolense (1L300) and a derived diminazene-resistant T. congolense strain (6C3), and for toxicity against U947 human cells and RAW 246.7 murine cells. Activity against T. b. brucei was higher than against T. congolense. Interestingly, the Tanzanian propolis extract was found to be more active than its fractions and purified compounds in these assays, with an IC50 of 1.20 μg/mL against T. b. brucei. The results of a cytotoxicity assay showed that the propolis extracts were less toxic than the purified compounds with mean IC50 values > 165.0 μg/mL. Two samples of propolis from East Africa display good activity against Trypanosoma brucei and T. congolense. Activity against both wild type and pentamidine and diminazene resistant forms. Two novel flavonoids and one known flavonoid were isolated from Tanzanian and Zambian propolis samples and characterized. Pure isolated compounds not much more active than crude extracts. Repeated observation of anti-protozoal activity shows the importance of propolis indefending the hive against infections.
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Affiliation(s)
- Samya S Alenezi
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, G40RE, Glasgow, UK
| | - Manal J Natto
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences University of Glasgow, Sir Graeme Davies Building 120 University Place, G12 8TA, Glasgow, Scotland, UK
| | - John O Igoli
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, G40RE, Glasgow, UK; Phytochemistry Research Group, Department of Chemistry, University of Agriculture, PMB 2373, Makurdi, Nigeria
| | - Alexander I Gray
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, G40RE, Glasgow, UK
| | | | | | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences University of Glasgow, Sir Graeme Davies Building 120 University Place, G12 8TA, Glasgow, Scotland, UK.
| | - David G Watson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, G40RE, Glasgow, UK.
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12
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Munday JC, Kunz S, Kalejaiye TD, Siderius M, Schroeder S, Paape D, Alghamdi AH, Abbasi Z, Huang SX, Donachie AM, William S, Sabra AN, Sterk GJ, Botros SS, Brown DG, Hoffman CS, Leurs R, de Koning HP. Cloning and functional complementation of ten Schistosoma mansoni phosphodiesterases expressed in the mammalian host stages. PLoS Negl Trop Dis 2020; 14:e0008447. [PMID: 32730343 PMCID: PMC7430754 DOI: 10.1371/journal.pntd.0008447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 08/17/2020] [Accepted: 06/02/2020] [Indexed: 01/29/2023] Open
Abstract
Only a single drug against schistosomiasis is currently available and new drug development is urgently required but very few drug targets have been validated and characterised. However, regulatory systems including cyclic nucleotide metabolism are emerging as primary candidates for drug discovery. Here, we report the cloning of ten cyclic nucleotide phosphodiesterase (PDE) genes of S. mansoni, out of a total of 11 identified in its genome. We classify these PDEs by homology to human PDEs. Male worms displayed higher expression levels for all PDEs, in mature and juvenile worms, and schistosomula. Several functional complementation approaches were used to characterise these genes. We constructed a Trypanosoma brucei cell line in which expression of a cAMP-degrading PDE complements the deletion of TbrPDEB1/B2. Inhibitor screens of these cells expressing only either SmPDE4A, TbrPDEB1 or TbrPDEB2, identified highly potent inhibitors of the S. mansoni enzyme that elevated the cellular cAMP concentration. We further expressed most of the cloned SmPDEs in two pde1Δ/pde2Δ strains of Saccharomyces cerevisiae and some also in a specialised strain of Schizosacharomyces pombe. Five PDEs, SmPDE1, SmPDE4A, SmPDE8, SmPDE9A and SmPDE11 successfully complemented the S. cerevisiae strains, and SmPDE7var also complemented to a lesser degree, in liquid culture. SmPDE4A, SmPDE8 and SmPDE11 were further assessed in S. pombe for hydrolysis of cAMP and cGMP; SmPDE11 displayed considerable preferrence for cGMP over cAMP. These results and tools enable the pursuit of a rigorous drug discovery program based on inhibitors of S. mansoni PDEs.
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Affiliation(s)
- Jane C. Munday
- Institute of Infection, Immunity and inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Stefan Kunz
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems, Vrije Universiteit Amsterdam, The Netherlands
| | - Titilola D. Kalejaiye
- Institute of Infection, Immunity and inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Marco Siderius
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems, Vrije Universiteit Amsterdam, The Netherlands
| | | | - Daniel Paape
- Institute of Infection, Immunity and inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Ali H. Alghamdi
- Institute of Infection, Immunity and inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Zainab Abbasi
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Sheng Xiang Huang
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Anne-Marie Donachie
- Institute of Infection, Immunity and inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Samia William
- Department of Pharmacology, Theodor Bilharz Research Institute, Warrak El-Hadar, Imbaba, Egypt
| | - Abdel Nasser Sabra
- Department of Pharmacology, Theodor Bilharz Research Institute, Warrak El-Hadar, Imbaba, Egypt
| | - Geert Jan Sterk
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems, Vrije Universiteit Amsterdam, The Netherlands
| | - Sanaa S. Botros
- Department of Pharmacology, Theodor Bilharz Research Institute, Warrak El-Hadar, Imbaba, Egypt
| | - David G. Brown
- School of Biosciences, University of Kent, United Kingdom
| | - Charles S. Hoffman
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Rob Leurs
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems, Vrije Universiteit Amsterdam, The Netherlands
| | - Harry P. de Koning
- Institute of Infection, Immunity and inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
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13
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Campagnaro GD, de Koning HP. Purine and pyrimidine transporters of pathogenic protozoa - conduits for therapeutic agents. Med Res Rev 2020; 40:1679-1714. [PMID: 32144812 DOI: 10.1002/med.21667] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 02/06/2023]
Abstract
Purines and pyrimidines are essential nutrients for any cell. Most organisms are able to synthesize their own purines and pyrimidines, but this ability was lost in protozoans that adapted to parasitism, leading to a great diversification in transporter activities in these organisms, especially for the acquisition of amino acids and nucleosides from their hosts throughout their life cycles. Many of these transporters have been shown to have sufficiently different substrate affinities from mammalian transporters, making them good carriers for therapeutic agents. In this review, we summarize the knowledge obtained on purine and pyrimidine activities identified in protozoan parasites to date and discuss their importance for the survival of these parasites and as drug carriers, as well as the perspectives of developments in the field.
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Affiliation(s)
- Gustavo D Campagnaro
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, 120 University Place, Glasgow, UK
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, 120 University Place, Glasgow, UK
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14
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Alotaibi A, Ebiloma GU, Williams R, Alenezi S, Donachie AM, Guillaume S, Igoli JO, Fearnley J, de Koning HP, Watson DG. European propolis is highly active against trypanosomatids including Crithidia fasciculata. Sci Rep 2019; 9:11364. [PMID: 31388043 PMCID: PMC6684629 DOI: 10.1038/s41598-019-47840-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/25/2019] [Indexed: 11/30/2022] Open
Abstract
Extracts of 35 samples of European propolis were tested against wild type and resistant strains of the protozoal pathogens Trypanosoma brucei, Trypanosoma congolense and Leishmania mexicana. The extracts were also tested against Crithidia fasciculata a close relative of Crithidia mellificae, a parasite of bees. Crithidia, Trypanosoma and Leishmania are all members of the order Kinetoplastida. High levels of activity were obtained for all the samples with the levels of activity varying across the sample set. The highest levels of activity were found against L. mexicana. The propolis samples were profiled by using liquid chromatography with high resolution mass spectrometry (LC-MS) and principal components analysis (PCA) of the data obtained indicated there was a wide variation in the composition of the propolis samples. Orthogonal partial least squares (OPLS) associated a butyrate ester of pinobanksin with high activity against T. brucei whereas in the case of T. congolense high activity was associated with methyl ethers of chrysin and pinobanksin. In the case of C. fasciculata highest activity was associated with methyl ethers of galangin and pinobanksin. OPLS modelling of the activities against L. mexicana using the mass spectrometry produced a less successful model suggesting a wider range of active components.
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Affiliation(s)
- Abdullah Alotaibi
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, UK
| | - Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Roderick Williams
- IBEHR, School of Health and Life Science, University of the West of Scotland, High Street, Paisley, PA1 2BE, UK
| | - Samya Alenezi
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, UK
| | - Anne-Marie Donachie
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Selome Guillaume
- IBEHR, School of Health and Life Science, University of the West of Scotland, High Street, Paisley, PA1 2BE, UK
| | - John O Igoli
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, UK
- Department of Chemistry, University of Agriculture, PMB 2373, Makurdi, Nigeria
| | | | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - David G Watson
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, UK.
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15
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Cerone M, Uliassi E, Prati F, Ebiloma GU, Lemgruber L, Bergamini C, Watson DG, de A M Ferreira T, Roth Cardoso GSH, Soares Romeiro LA, de Koning HP, Bolognesi ML. Discovery of Sustainable Drugs for Neglected Tropical Diseases: Cashew Nut Shell Liquid (CNSL)-Based Hybrids Target Mitochondrial Function and ATP Production in Trypanosoma brucei. ChemMedChem 2019; 14:621-635. [PMID: 30664325 PMCID: PMC6686156 DOI: 10.1002/cmdc.201800790] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Indexed: 02/02/2023]
Abstract
In the search for effective and sustainable drugs for human African trypanosomiasis (HAT), we developed hybrid compounds by merging the structural features of quinone 4 (2‐phenoxynaphthalene‐1,4‐dione) with those of phenolic constituents from cashew nut shell liquid (CNSL). CNSL is a waste product from cashew nut processing factories, with great potential as a source of drug precursors. The synthesized compounds were tested against Trypanosoma brucei brucei, including three multidrug‐resistant strains, T. congolense, and a human cell line. The most potent activity was found against T. b. brucei, the causative agent of HAT. Shorter‐chain derivatives 20 (2‐(3‐(8‐hydroxyoctyl)phenoxy)‐5‐methoxynaphthalene‐1,4‐dione) and 22 (5‐hydroxy‐2‐(3‐(8‐hydroxyoctyl)phenoxy)naphthalene‐1,4‐dione) were more active than 4, displaying rapid micromolar trypanocidal activity, and no human cytotoxicity. Preliminary studies probing their mode of action on trypanosomes showed ATP depletion, followed by mitochondrial membrane depolarization and mitochondrion ultrastructural damage. This was accompanied by reactive oxygen species production. We envisage that such compounds, obtained from a renewable and inexpensive material, might be promising bio‐based sustainable hits for anti‐trypanosomatid drug discovery.
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Affiliation(s)
- Michela Cerone
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy.,Institute of Infection, Immunity and Inflammation, University of Glasgow, GBRC, University Place, G12 8AT, Glasgow, UK
| | - Elisa Uliassi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy
| | - Federica Prati
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy
| | - Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, University of Glasgow, GBRC, University Place, G12 8AT, Glasgow, UK.,Department of Biochemistry, Faculty of Natural Sciences, Kogi State University, P.M.B. 1008, Anyigba, Kogi State, Nigeria
| | - Leandro Lemgruber
- Institute of Infection, Immunity and Inflammation, University of Glasgow, GBRC, University Place, G12 8AT, Glasgow, UK.,Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, GBRC, University Place, G12 8AT, Glasgow, UK
| | - Christian Bergamini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy
| | - David G Watson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 16 Richmond Street, G1 1XQ, Glasgow, UK
| | - Thais de A M Ferreira
- Department of Pharmacy, Health Sciences Faculty, University of Brasília, Campus Universitário Darcy Ribeiro, 70910-900, Brasília, DF, Brazil
| | - Gabriella Simões Heyn Roth Cardoso
- Department of Pharmacy, Health Sciences Faculty, University of Brasília, Campus Universitário Darcy Ribeiro, 70910-900, Brasília, DF, Brazil
| | - Luiz A Soares Romeiro
- Department of Pharmacy, Health Sciences Faculty, University of Brasília, Campus Universitário Darcy Ribeiro, 70910-900, Brasília, DF, Brazil
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, GBRC, University Place, G12 8AT, Glasgow, UK
| | - Maria Laura Bolognesi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy
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16
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Campagnaro GD, de Freitas Nascimento J, Girard RB, Silber AM, de Koning HP. Cloning and characterisation of the Equilibrative Nucleoside Transporter family of Trypanosoma cruzi: ultra-high affinity and selectivity to survive in the intracellular niche. Biochim Biophys Acta Gen Subj 2018; 1862:2750-2763. [DOI: 10.1016/j.bbagen.2018.08.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/22/2018] [Accepted: 08/23/2018] [Indexed: 12/27/2022]
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17
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Ebiloma GU, Katsoulis E, Igoli JO, Gray AI, De Koning HP. Multi-target mode of action of a Clerodane-type diterpenoid from Polyalthia longifolia targeting African trypanosomes. Sci Rep 2018; 8:4613. [PMID: 29545637 PMCID: PMC5854603 DOI: 10.1038/s41598-018-22908-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/19/2018] [Indexed: 11/09/2022] Open
Abstract
Natural products have made remarkable contributions to drug discovery and therapy. In this work we exploited various biochemical approaches to investigate the mode of action of 16-α-hydroxy-cleroda-3,13 (14)-Z-dien-15,16-olide (HDK-20), which we recently isolated from Polyalthia longifolia, on Trypanosoma brucei bloodstream trypomastigotes. HDK20 at concentrations ≥ EC50 (0.4 μg/ml) was trypanocidal, with its effect irreversible after only a brief exposure time (<1 h). Fluorescence microscopic assessment of DNA configuration revealed severe cell cycle defects after 8 h of incubation with the compound, the equivalent of a single generation time. This was accompanied by DNA fragmentation as shown by Terminal deoxynucleotidyl transferase dUTP Nick-End Labelling (TUNEL) assays. HDK-20 also induced a fast and profound depolarisation of the parasites’ mitochondrial membrane potential and depleted intracellular ATP levels of T. brucei. Overall, HDK20 showed a multi-target mechanism of action, which provides a biochemical explanation for the promising anti-trypanosomatid activity in our previous report.
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Affiliation(s)
- Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,Department of Biochemistry, Faculty of Natural Sciences, Kogi State University, Anyigba, Nigeria
| | - Evangelos Katsoulis
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - John O Igoli
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.,Department of Chemistry, College of Science, University of Agriculture, Makurdi, Nigeria
| | - Alexander I Gray
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Harry P De Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
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18
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Campagnaro GD, Alzahrani KJ, Munday JC, De Koning HP. Trypanosoma brucei bloodstream forms express highly specific and separate transporters for adenine and hypoxanthine; evidence for a new protozoan purine transporter family? Mol Biochem Parasitol 2018; 220:46-56. [DOI: 10.1016/j.molbiopara.2018.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/10/2018] [Accepted: 01/19/2018] [Indexed: 10/18/2022]
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Fresh insights into the pyrimidine metabolism in the trypanosomatids. Parasit Vectors 2018; 11:87. [PMID: 29422065 PMCID: PMC5803862 DOI: 10.1186/s13071-018-2660-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/18/2018] [Indexed: 11/26/2022] Open
Abstract
The trypanosomatid parasites continue their killing spree resulting in significant annual mortality due to the lack of effective treatments and the prominence of these diseases in poorer countries. These dimorphic parasites thrive unchecked in the host system, outsmarting the immune mechanisms. An understanding of biology of these parasitic forms will help in the management and elimination of these fatal diseases. Investigation of various metabolic pathways in these parasites has shed light in the understanding of the unique biology of the trypansomatids. An understanding of these pathways have helped in tracing the soft targets in the metabolic pathways, which could be used as effective drug targets which would further impact the therupeutic implications. Pyrimidine pathway is a vital metabolic pathway which yields in the formation of pyrimidines, which are then integrated in nucleic acids (DNA and RNA) in sugars (UDP sugars) and lipids (CDP lipids). A wealth of data and information has been generated in the past decades by in-depth analyses of pyrimidine pathway in the trypanosomatid parasites, which can aid in the identification of anomalies between the parasitic and host counterpart which could be further harnessed to develop therapeutic interventions for the treatment of parasitic diseases. This review presents an updated and comprehensive detailing of the pyrimidine metabolism in the trypansomatids, their uniqueness and their distinctions, and its possible outcomes that would aid in the eradication of these parasitic diseases.
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El Kouni MH. Pyrimidine metabolism in schistosomes: A comparison with other parasites and the search for potential chemotherapeutic targets. Comp Biochem Physiol B Biochem Mol Biol 2017; 213:55-80. [PMID: 28735972 PMCID: PMC5593796 DOI: 10.1016/j.cbpb.2017.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/29/2017] [Accepted: 07/03/2017] [Indexed: 12/18/2022]
Abstract
Schistosomes are responsible for the parasitic disease schistosomiasis, an acute and chronic parasitic ailment that affects >240 million people in 70 countries worldwide. It is the second most devastating parasitic disease after malaria. At least 200,000 deaths per year are associated with the disease. In the absence of the availability of vaccines, chemotherapy is the main stay for combating schistosomiasis. The antischistosomal arsenal is currently limited to a single drug, Praziquantel, which is quite effective with a single-day treatment and virtually no host-toxicity. Recently, however, the question of reduced activity of Praziquantel has been raised. Therefore, the search for alternative antischistosomal drugs merits the study of new approaches of chemotherapy. The rational design of a drug is usually based on biochemical and physiological differences between pathogens and host. Pyrimidine metabolism is an excellent target for such studies. Schistosomes, unlike most of the host tissues, require a very active pyrimidine metabolism for the synthesis of DNA and RNA. This is essential for the production of the enormous numbers of eggs deposited daily by the parasite to which the granulomas response precipitates the pathogenesis of schistosomiasis. Furthermore, there are sufficient differences between corresponding enzymes of pyrimidine metabolism from the host and the parasite that can be exploited to design specific inhibitors or "subversive substrates" for the parasitic enzymes. Specificities of pyrimidine transport also diverge significantly between parasites and their mammalian host. This review deals with studies on pyrimidine metabolism in schistosomes and highlights the unique characteristic of this metabolism that could constitute excellent potential targets for the design of safe and effective antischistosomal drugs. In addition, pyrimidine metabolism in schistosomes is compared with that in other parasites where studies on pyrimidine metabolism have been more elaborate, in the hope of providing leads on how to identify likely chemotherapeutic targets which have not been looked at in schistosomes.
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Affiliation(s)
- Mahmoud H El Kouni
- Department of Pharmacology and Toxicology, Center for AIDS Research, Comprehensive Cancer Center, General Clinical Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Alzahrani KJH, Ali JAM, Eze AA, Looi WL, Tagoe DNA, Creek DJ, Barrett MP, de Koning HP. Functional and genetic evidence that nucleoside transport is highly conserved in Leishmania species: Implications for pyrimidine-based chemotherapy. Int J Parasitol Drugs Drug Resist 2017; 7:206-226. [PMID: 28453984 PMCID: PMC5407577 DOI: 10.1016/j.ijpddr.2017.04.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 04/14/2017] [Accepted: 04/18/2017] [Indexed: 11/28/2022]
Abstract
Leishmania pyrimidine salvage is replete with opportunities for therapeutic intervention with enzyme inhibitors or antimetabolites. Their uptake into cells depends upon specific transporters; therefore it is essential to establish whether various Leishmania species possess similar pyrimidine transporters capable of drug uptake. Here, we report a comprehensive characterization of pyrimidine transport in L. major and L. mexicana. In both species, two transporters for uridine/adenosine were detected, one of which also transported uracil and the antimetabolites 5-fluoruracil (5-FU) and 5F,2'deoxyuridine (5F,2'dUrd), and was designated uridine-uracil transporter 1 (UUT1); the other transporter mediated uptake of adenosine, uridine, 5F,2'dUrd and thymidine and was designated Nucleoside Transporter 1 (NT1). To verify the reported L. donovani model of two NT1-like genes encoding uridine/adenosine transporters, and an NT2 gene encoding an inosine transporter, we cloned the corresponding L. major and L. mexicana genes, expressing each in T. brucei. Consistent with the L. donovani reports, the NT1-like genes of either species mediated the adenosine-sensitive uptake of [3H]-uridine but not of [3H]-inosine. Conversely, the NT2-like genes mediated uptake of [3H]-inosine but not [3H]-uridine. Among pyrimidine antimetabolites tested, 5-FU and 5F,2'dUrd were the most effective antileishmanials; resistance to both analogs was induced in L. major and L. mexicana. In each case it was found that the resistant cells had lost the transport capacity for the inducing drug. Metabolomics analysis found that the mechanism of action of 5-FU and 5F-2'dUrd was similar in both Leishmania species, with major changes in deoxynucleotide metabolism. We conclude that the pyrimidine salvage system is highly conserved in Leishmania species - essential information for the development of pyrimidine-based chemotherapy.
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Affiliation(s)
- Khalid J H Alzahrani
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; Department of Clinical Laboratory, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Juma A M Ali
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; Al Jabal Al Gharbi University, Gharyan, Libya
| | - Anthonius A Eze
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; Department of Medical Biochemistry, College of Medicine, University of Nigeria, Enugu Campus, Enugu, Nigeria
| | - Wan Limm Looi
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Daniel N A Tagoe
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Darren J Creek
- Department of Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Michael P Barrett
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom; Wellcome Trust Centre for Molecular Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
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Ebiloma GU, Igoli JO, Katsoulis E, Donachie AM, Eze A, Gray AI, de Koning HP. Bioassay-guided isolation of active principles from Nigerian medicinal plants identifies new trypanocides with low toxicity and no cross-resistance to diamidines and arsenicals. JOURNAL OF ETHNOPHARMACOLOGY 2017; 202:256-264. [PMID: 28336470 DOI: 10.1016/j.jep.2017.03.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/19/2017] [Accepted: 03/18/2017] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Leaves from the plant species studied herein are traditionally used in northern Nigeria against various protozoan infections. However, none of these herbal preparations have been standardized, nor have their toxicity to mammalian cells been investigated. In search of improved and non-toxic active antiprotozoal principles that are not cross-resistant with current anti-parasitics, we here report the results of the in vitro screening of extracts from seven selected medicinal plant species (Centrosema pubescens, Moringa oleifera, Tridax procumbens, Polyalthia longifolia, Newbouldia laevis, Eucalyptus maculate, Jathropha tanjorensis), used traditionally to treat kinetoplastid infections in Nigeria, and the isolation of their bioactive principles. AIM OF THE STUDY To investigate the efficacies of medicinal plant extracts, and of compounds isolated therefrom, against kinetoplastid parasites, assess cross-resistance to existing chemotherapy, and assay their toxicity against mammalian cells in vitro. MATERIAL AND METHODS Plants were extracted with hexane, ethyl acetate and methanol. Active principles were isolated by bioassay-led fractionation, testing for trypanocidal activity, and identified using NMR and mass spectrometry. EC50 values for their activity against wild-type and multi-drug resistant Trypanosoma brucei were obtained using the viability indicator dye resazurin. RESULTS Seven medicinal plants were evaluated for activity against selected kinetoplastid parasites. The result shows that crude extracts and isolated active compounds from Polyalthia longifolia and Eucalyptus maculata, in particular, display promising activity against drug-sensitive and multi-drug resistant Trypanosoma brucei. The EC50 value of a clerodane (16α-hydroxy-cleroda-3,13(14)-Z-dien-15,16-olide) isolated from Polyalthia longifolia was as low as 0.38µg/mL, while a triterpenoid (3β,13β-dihydroxy-urs-11-en-28-oic acid) isolated from Eucalyptus maculata displayed an EC50 of 1.58µg/mL. None of the isolated compounds displayed toxicity towards Human Embryonic Kidney cells at concentrations up to 400µg/mL. In addition, the isolated compounds were active against Leishmania mexicana, as well as against T. congolense. CONCLUSION We have isolated a clerodane compound from Polyalthia longifolia that shows low toxicity, no cross-resistance with current treatments, and promising activity against both human-infective and veterinary Trypanosoma species.
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Affiliation(s)
- Godwin Unekwuojo Ebiloma
- Institute of Infection, Immunity and Inflammation, University of Glasgow, United Kingdom; Department of Biochemistry, Faculty of Natural Sciences, Kogi State University, Nigeria
| | - John Ogbaji Igoli
- Department of Chemistry, College of Science, University of Agriculture, Makurdi, Nigeria; Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Evangelos Katsoulis
- Institute of Infection, Immunity and Inflammation, University of Glasgow, United Kingdom
| | - Anne-Marie Donachie
- Institute of Infection, Immunity and Inflammation, University of Glasgow, United Kingdom
| | - Anthonius Eze
- Department of Biochemistry, College of Health sciences, University of Nigeria, Nigeria
| | - Alexander Ian Gray
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, United Kingdom.
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Bobba V, Nanavaty V, Idippily ND, Zhao A, Li B, Su B. Synthesis and biological evaluation of selective tubulin inhibitors as anti-trypanosomal agents. Bioorg Med Chem 2017; 25:3215-3222. [PMID: 28428042 DOI: 10.1016/j.bmc.2017.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 03/30/2017] [Accepted: 04/05/2017] [Indexed: 11/28/2022]
Abstract
African trypanosomiasis is still a threat to human health due to the severe side-effects of current drugs. We identified selective tubulin inhibitors that showed the promise to the treatment of this disease, which was based on the tubulin protein structural difference between mammalian and trypanosome cells. Further lead optimization was performed in the current study to improve the efficiency of the drug candidates. We used Trypanosoma brucei brucei cells as the parasite model, and human normal kidney cells and mouse macrophage cells as the host model to evaluate the compounds. One new analog showed great potency with an IC50 of 70nM to inhibit the growth of trypanosome cells and did not affect the viability of mammalian cells. Western blot analyses reveal that the compound decreased tubulin polymerization in T. brucei cells. A detailed structure activity relationship (SAR) was summarized that will be used to guide future lead optimization.
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Affiliation(s)
- Viharika Bobba
- Department of Chemistry, Center for Gene Regulation in Health and Disease, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Ave., Cleveland, OH 44115, USA
| | - Vishal Nanavaty
- Department of Biology, Geo. & Env. Sciences, Center for Gene Regulation in Health and Disease, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Ave., Cleveland, OH 44115, USA
| | - Nethrie D Idippily
- Department of Chemistry, Center for Gene Regulation in Health and Disease, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Ave., Cleveland, OH 44115, USA
| | - Anran Zhao
- Department of Chemistry, Center for Gene Regulation in Health and Disease, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Ave., Cleveland, OH 44115, USA
| | - Bibo Li
- Department of Biology, Geo. & Env. Sciences, Center for Gene Regulation in Health and Disease, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Ave., Cleveland, OH 44115, USA.
| | - Bin Su
- Department of Chemistry, Center for Gene Regulation in Health and Disease, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Ave., Cleveland, OH 44115, USA.
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Eze AA, Gould MK, Munday JC, Tagoe DNA, Stelmanis V, Schnaufer A, De Koning HP. Reduced Mitochondrial Membrane Potential Is a Late Adaptation of Trypanosoma brucei brucei to Isometamidium Preceded by Mutations in the γ Subunit of the F1Fo-ATPase. PLoS Negl Trop Dis 2016; 10:e0004791. [PMID: 27518185 PMCID: PMC4982688 DOI: 10.1371/journal.pntd.0004791] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/30/2016] [Indexed: 11/19/2022] Open
Abstract
Background Isometamidium is the main prophylactic drug used to prevent the infection of livestock with trypanosomes that cause Animal African Trypanosomiasis. As well as the animal infective trypanosome species, livestock can also harbor the closely related human infective subspecies T. b. gambiense and T. b. rhodesiense. Resistance to isometamidium is a growing concern, as is cross-resistance to the diamidine drugs diminazene and pentamidine. Methodology/Principal Findings Two isometamidium resistant Trypanosoma brucei clones were generated (ISMR1 and ISMR15), being 7270- and 16,000-fold resistant to isometamidium, respectively, which retained their ability to grow in vitro and establish an infection in mice. Considerable cross-resistance was shown to ethidium bromide and diminazene, with minor cross-resistance to pentamidine. The mitochondrial membrane potentials of both resistant cell lines were significantly reduced compared to the wild type. The net uptake rate of isometamidium was reduced 2-3-fold but isometamidium efflux was similar in wild-type and resistant lines. Fluorescence microscopy and PCR analysis revealed that ISMR1 and ISMR15 had completely lost their kinetoplast DNA (kDNA) and both lines carried a mutation in the nuclearly encoded γ subunit gene of F1 ATPase, truncating the protein by 22 amino acids. The mutation compensated for the loss of the kinetoplast in bloodstream forms, allowing near-normal growth, and conferred considerable resistance to isometamidium and ethidium as well as significant resistance to diminazene and pentamidine, when expressed in wild type trypanosomes. Subsequent exposure to either isometamidium or ethidium led to rapid loss of kDNA and a further increase in isometamidium resistance. Conclusions/Significance Sub-lethal exposure to isometamidium gives rise to viable but highly resistant trypanosomes that, depending on sub-species, are infective to humans and cross-resistant to at least some diamidine drugs. The crucial mutation is in the F1 ATPase γ subunit, which allows loss of kDNA and results in a reduction of the mitochondrial membrane potential. Isometamidium is the only prophylactic treatment of Animal African Trypanosomiasis, a wasting disease of livestock and domestic animals in sub-Saharan Africa. Unfortunately resistance threatens the continued utility of this drug after decades of use. Not only does this disease have severe impacts on agriculture, but some subspecies of Trypanosoma brucei are human-infective as well (causing sleeping sickness) and there is concern that cross-resistance with trypanocides of the diamidine class could further undermine treatment of both veterinary and human infections. It is therefore essential to understand the mechanism of isometamidium resistance and the likelihood for cross-resistance with other first-line trypanocides. Here, we report that isometamidium resistance can be caused by a mutation in an important mitochondrial protein, the γ subunit of the F1 ATPase, and that this mutation alone is sufficient for high levels of resistance, cross-resistance to various drugs, and a strongly reduced mitochondrial membrane potential. This report will for the first time enable a structural assessment of isometamidium resistance genes in T. brucei spp.
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Affiliation(s)
- Anthonius A. Eze
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Matthew K. Gould
- Institute for Immunology and Infection Research and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Jane C. Munday
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Daniel N. A. Tagoe
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Valters Stelmanis
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Achim Schnaufer
- Institute for Immunology and Infection Research and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Harry P. De Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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25
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Nanavaty V, Lama R, Sandhu R, Zhong B, Kulman D, Bobba V, Zhao A, Li B, Su B. Orally Active and Selective Tubulin Inhibitors as Anti-Trypanosome Agents. PLoS One 2016; 11:e0146289. [PMID: 26771307 PMCID: PMC4714897 DOI: 10.1371/journal.pone.0146289] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/15/2015] [Indexed: 11/21/2022] Open
Abstract
Objectives There is an urgent need to develop a safe, effective, orally active, and inexpensive therapy for African trypanosomiasis due to the drawbacks of current drugs. Selective tubulin inhibitors have the potential to be promising drug candidates for the treatment of this disease, which is based on the tubulin protein structural difference between mammalian and trypanosome cells. We propose to identify novel tubulin inhibitors from a compound library developed based on the lead compounds that selectively target trypanosomiasis. Methods We used Trypanosoma brucei brucei as the parasite model, and human normal kidney cells and mouse microphage cells as the host model. Growth rates of both trypanosomes and mammalian cells were determined as a means to screen compounds that selectively inhibit the proliferation of parasites. Furthermore, we examined the cell cycle profile of the parasite and compared tubulin polymerization dynamics before and after the treatment using identified compounds. Last, in vivo anti-parasite activities of these compounds were determined in T. brucei-infected mice. Results Three compounds were selected that are 100 fold more effective against the growth of T. brucei cells than mammalian cells. These compounds caused cell cycle progression defects in T. brucei cells. Western analyses indicated that these compounds decreased tubulin polymerization in T. brucei cells. The in vivo investigation revealed that these compounds, when admitted orally, inhibited T. brucei cell proliferation in mouse blood. However, they were not potent enough to clear up the infection completely. Conclusions These compounds are promising lead compounds as orally active agents for drug development of anti-trypanosome agents. A more detail structure activity relationship (SAR) was summarized that will be used to guide future lead optimization to improve the selectivity and potency of the current compounds.
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Affiliation(s)
- Vishal Nanavaty
- Department of Biology, Geo. & Env. Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
| | - Rati Lama
- Department of Chemistry, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
| | - Ranjodh Sandhu
- Department of Biology, Geo. & Env. Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
| | - Bo Zhong
- Department of Chemistry, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
| | - Daniel Kulman
- Department of Biology, Geo. & Env. Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
| | - Viharika Bobba
- Department of Chemistry, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
| | - Anran Zhao
- Department of Chemistry, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
| | - Bibo Li
- Department of Biology, Geo. & Env. Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America.,Center for Gene Regulation in Health and Disease, College of Sciences & Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
| | - Bin Su
- Department of Chemistry, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America.,Center for Gene Regulation in Health and Disease, College of Sciences & Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio, 44115, United States of America
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26
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Kim DH, Achcar F, Breitling R, Burgess KE, Barrett MP. LC-MS-based absolute metabolite quantification: application to metabolic flux measurement in trypanosomes. Metabolomics 2015; 11:1721-1732. [PMID: 26491423 PMCID: PMC4605981 DOI: 10.1007/s11306-015-0827-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/25/2015] [Indexed: 01/15/2023]
Abstract
Human African trypanosomiasis is a neglected tropical disease caused by the protozoan parasite, Trypanosoma brucei. In the mammalian bloodstream, the trypanosome's metabolism differs significantly from that of its host. For example, the parasite relies exclusively on glycolysis for energy source. Recently, computational and mathematical models of trypanosome metabolism have been generated to assist in understanding the parasite metabolism with the aim of facilitating drug development. Optimisation of these models requires quantitative information, including metabolite concentrations and/or metabolic fluxes that have been hitherto unavailable on a large scale. Here, we have implemented an LC-MS-based method that allows large scale quantification of metabolite levels by using U-13C-labelled E.coli extracts as internal standards. Known amounts of labelled E. coli extract were added into the parasite samples, as well as calibration standards, and used to obtain calibration curves enabling us to convert intensities into concentrations. This method allowed us to reliably quantify the changes of 43 intracellular metabolites and 32 extracellular metabolites in the medium over time. Based on the absolute quantification, we were able to compute consumption and production fluxes. These quantitative data can now be used to optimise computational models of parasite metabolism.
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Affiliation(s)
- Dong-Hyun Kim
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA UK
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Fiona Achcar
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA UK
| | - Rainer Breitling
- Manchester Centre of Synthetic Biology for Fine and Speciality Chemicals, Manchester Institute of Biotechnology, Faculty of Life Sciences, University of Manchester, Manchester, M1 7DN UK
| | - Karl E. Burgess
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G61 1QH UK
| | - Michael P. Barrett
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA UK
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G61 1QH UK
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27
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Alkhaldi AAM, Creek DJ, Ibrahim H, Kim DH, Quashie NB, Burgess KE, Changtam C, Barrett MP, Suksamrarn A, de Koning HP. Potent trypanocidal curcumin analogs bearing a monoenone linker motif act on trypanosoma brucei by forming an adduct with trypanothione. Mol Pharmacol 2014; 87:451-64. [PMID: 25527638 DOI: 10.1124/mol.114.096016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We have previously reported that curcumin analogs with a C7 linker bearing a C4-C5 olefinic linker with a single keto group at C3 (enone linker) display midnanomolar activity against the bloodstream form of Trypanosoma brucei. However, no clear indication of their mechanism of action or superior antiparasitic activity relative to analogs with the original di-ketone curcumin linker was apparent. To further investigate their utility as antiparasitic agents, we compare the cellular effects of curcumin and the enone linker lead compound 1,7-bis(4-hydroxy-3-methoxyphenyl)hept-4-en-3-one (AS-HK014) here. An AS-HK014-resitant line, trypanosomes adapted to AS-HK014 (TA014), was developed by in vitro exposure to the drug. Metabolomic analysis revealed that exposure to AS-HK014, but not curcumin, rapidly depleted glutathione and trypanothione in the wild-type line, although almost all other metabolites were unchanged relative to control. In TA014 cells, thiol levels were similar to untreated wild-type cells and not significantly depleted by AS-HK014. Adducts of AS-HK014 with both glutathione and trypanothione were identified in AS-HK014-exposed wild-type cells and reproduced by chemical reaction. However, adduct accumulation in sensitive cells was much lower than in resistant cells. TA014 cells did not exhibit any changes in sequence or protein levels of glutathione synthetase and γ-glutamylcysteine synthetase relative to wild-type cells. We conclude that monoenone curcuminoids have a different mode of action than curcumin, rapidly and specifically depleting thiol levels in trypanosomes by forming an adduct. This adduct may ultimately be responsible for the highly potent trypanocidal and antiparasitic activity of the monoenone curcuminoids.
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Affiliation(s)
- Abdulsalam A M Alkhaldi
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Darren J Creek
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Hasan Ibrahim
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Dong-Hyun Kim
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Neils B Quashie
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Karl E Burgess
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Chatchawan Changtam
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Michael P Barrett
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Apichart Suksamrarn
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom (A.A.M.A, D.J.C., H.I., D.-H.K., N.B.Q., K.E.B., M.P.B., H.P.K.); Department of Biology, College of Science, Aljouf University, Skaka, Kingdom of Saudi Arabia (A.A.M.A); Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Australia (D.J.C.); Faculty of Science, Department of Zoology, Sebha University, Libya (H.I.); Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom (D.-H.K.); Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana (N.B.Q.); Division of Physical Science, Faculty of Science and Technology, Huachiew Chalermprakiet University, Samutprakarn, Thailand (C.C.); Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom (M.P.B.); and Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand (A.S.)
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Ritt JF, Raymond F, Leprohon P, Légaré D, Corbeil J, Ouellette M. Gene amplification and point mutations in pyrimidine metabolic genes in 5-fluorouracil resistant Leishmania infantum. PLoS Negl Trop Dis 2013; 7:e2564. [PMID: 24278495 PMCID: PMC3836990 DOI: 10.1371/journal.pntd.0002564] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 10/15/2013] [Indexed: 12/02/2022] Open
Abstract
Background The human protozoan parasites Leishmania are prototrophic for pyrimidines with the ability of both de novo biosynthesis and uptake of pyrimidines. Methodology/Principal Findings Five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU) in the hope to better understand the metabolism of pyrimidine in Leishmania. Analysis of the 5-FU mutants by comparative genomic hybridization and whole genome sequencing revealed in selected mutants the amplification of DHFR-TS and a deletion of part of chromosome 10. Point mutations in uracil phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also observed in three individual resistant mutants. Transfection experiments confirmed that these point mutations were responsible for 5-FU resistance. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import. Conclusion/Significance This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist and lead to resistance in Leishmania. The human protozoan parasites Leishmania present the ability of both de novo biosynthesis and uptake of pyrimidines. The pyrimidine pathway is not well understood in these parasites. In the hope to better understand the pyrimidine pathway in Leishmania, five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU). Analysis of the 5-FU mutants by comparative genomic hybridization and whole genome sequencing revealed the amplification of the main target enzyme DHFR-TS, and point mutations in three important metabolic enzymes. Transfection experiments confirmed that these point mutations were responsible for 5-FU resistance. Transport studies also revealed that one resistant mutant was defective for uracil and 5-FU import. Overall, this study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist and lead to resistance in these protozoa.
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Affiliation(s)
- Jean-François Ritt
- Centre de recherche en Infectiologie du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Université Laval, Québec City, Québec, Canada
| | - Frédéric Raymond
- Centre de recherche en Infectiologie du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Université Laval, Québec City, Québec, Canada
| | - Philippe Leprohon
- Centre de recherche en Infectiologie du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Université Laval, Québec City, Québec, Canada
| | - Danielle Légaré
- Centre de recherche en Infectiologie du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Université Laval, Québec City, Québec, Canada
| | - Jacques Corbeil
- Centre de recherche en Infectiologie du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Université Laval, Québec City, Québec, Canada
| | - Marc Ouellette
- Centre de recherche en Infectiologie du CHU de Québec and Département de Microbiologie, Infectiologie et Immunologie, Université Laval, Québec City, Québec, Canada
- * E-mail:
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Ong HB, Sienkiewicz N, Wyllie S, Patterson S, Fairlamb AH. Trypanosoma brucei (UMP synthase null mutants) are avirulent in mice, but recover virulence upon prolonged culture in vitro while retaining pyrimidine auxotrophy. Mol Microbiol 2013; 90:443-55. [PMID: 23980694 PMCID: PMC3868941 DOI: 10.1111/mmi.12376] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2013] [Indexed: 11/30/2022]
Abstract
African trypanosomes are capable of both de novo synthesis and salvage of pyrimidines. The last two steps in de novo synthesis are catalysed by UMP synthase (UMPS) – a bifunctional enzyme comprising orotate phosphoribosyl transferase (OPRT) and orotidine monophosphate decarboxylase (OMPDC). To investigate the essentiality of pyrimidine biosynthesis in Trypanosoma brucei, we generated a umps double knockout (DKO) line by gene replacement. The DKO was unable to grow in pyrimidine-depleted medium in vitro, unless supplemented with uracil, uridine, deoxyuridine or UMP. DKO parasites were completely resistant to 5-fluoroorotate and hypersensitive to 5-fluorouracil, consistent with loss of UMPS, but remained sensitive to pyrazofurin indicating that, unlike mammalian cells, the primary target of pyrazofurin is not OMPDC. The null mutant was unable to infect mice indicating that salvage of host pyrimidines is insufficient to support growth. However, following prolonged culture in vitro, parasites regained virulence in mice despite retaining pyrimidine auxotrophy. Unlike the wild-type, both pyrimidine auxotrophs secreted substantial quantities of orotate, significantly higher in the virulent DKO line. We propose that this may be responsible for the recovery of virulence in mice, due to host metabolism converting orotate to uridine, thereby bypassing the loss of UMPS in the parasite.
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Affiliation(s)
- Han B Ong
- Divisional of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
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Ali JAM, Tagoe DNA, Munday JC, Donachie A, Morrison LJ, de Koning HP. Pyrimidine biosynthesis is not an essential function for Trypanosoma brucei bloodstream forms. PLoS One 2013; 8:e58034. [PMID: 23505454 PMCID: PMC3591441 DOI: 10.1371/journal.pone.0058034] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 01/29/2013] [Indexed: 11/18/2022] Open
Abstract
Background African trypanosomes are capable of both pyrimidine biosynthesis and salvage of preformed pyrimidines from the host, but it is unknown whether either process is essential to the parasite. Methodology/Principal Findings Pyrimidine requirements for growth were investigated using strictly pyrimidine-free media, with or without single added pyrimidine sources. Growth rates of wild-type bloodstream form Trypanosoma brucei brucei were unchanged in pyrimidine-free medium. The essentiality of the de novo pyrimidine biosynthesis pathway was studied by knocking out the PYR6-5 locus that produces a fusion product of orotate phosphoribosyltransferase (OPRT) and Orotidine Monophosphate Decarboxylase (OMPDCase). The pyrimidine auxotroph was dependent on a suitable extracellular pyrimidine source. Pyrimidine starvation was rapidly lethal and non-reversible, causing incomplete DNA content in new cells. The phenotype could be rescued by addition of uracil; supplementation with uridine, 2′deoxyuridine, and cytidine allowed a diminished growth rate and density. PYR6-5−/− trypanosomes were more sensitive to pyrimidine antimetabolites and displayed increased uracil transport rates and uridine phosphorylase activity. Pyrimidine auxotrophs were able to infect mice although the infection developed much more slowly than infection with the parental, prototrophic trypanosome line. Conclusions/Significance Pyrimidine salvage was not an essential function for bloodstream T. b. brucei. However, trypanosomes lacking de novo pyrimidine biosynthesis are completely dependent on an extracellular pyrimidine source, strongly preferring uracil, and display reduced infectivity. As T. brucei are able to salvage sufficient pyrimidines from the host environment, the pyrimidine biosynthesis pathway is not a viable drug target, although any interruption of pyrimidine supply was lethal.
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Affiliation(s)
- Juma A. M. Ali
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Faculty of Science, Department of Zoology, Al Jabal Al Gharbi University, Gharyan, Libya
| | - Daniel N. A. Tagoe
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jane C. Munday
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Anne Donachie
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Liam J. Morrison
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
- Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
| | - Harry P. de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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Castillo-Acosta VM, Aguilar-Pereyra F, García-Caballero D, Vidal AE, Ruiz-Pérez LM, González-Pacanowska D. Pyrimidine requirements in deoxyuridine triphosphate nucleotidohydrolase deficient Trypanosoma brucei mutants. Mol Biochem Parasitol 2012. [PMID: 23201394 DOI: 10.1016/j.molbiopara.2012.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Trypanosomal all-alpha dUTPases are homodimeric enzymes that catalyze the hydrolysis of dUTP and dUDP to dUMP and PPi. Trypanosomes lack dCTP/dCMP deaminase and therefore strongly depend on dUDP/dUTP hydrolysis for dUMP production. Here we have addressed by gene replacement the consequences of elimination of dUTPase activity in bloodstream forms of Trypanosoma brucei. We first generated conditional DUT-knockout strains that allowed an effective decrease of dUTPase resulting in proliferation arrest, although gene repression could not be sustained long enough to cause lethality. Alternatively, DUT null mutants could be isolated in the presence of high levels of thymidine while exogenous supplementation with uracil, uridine or deoxyuridine could not complement metabolically the dUTPase deficiency. Upon thymidine removal, trypanosomes exhibited impaired proliferation and eventually died. These data establish a strict requirement for dUTPase in T. brucei viability and support a major role of the enzyme in the provision of pyrimidine nucleotides in kinetoplastids.
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Affiliation(s)
- Víctor M Castillo-Acosta
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n 18100-Armilla (Granada), Spain
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Ali JAM, Creek DJ, Burgess K, Allison HC, Field MC, Mäser P, De Koning HP. Pyrimidine salvage in Trypanosoma brucei bloodstream forms and the trypanocidal action of halogenated pyrimidines. Mol Pharmacol 2012. [PMID: 23188714 DOI: 10.1124/mol.112.082321] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
African trypanosomes are capable of both pyrimidine biosynthesis and salvage of preformed pyrimidines from the host. However, uptake of pyrimidines in bloodstream form trypanosomes has not been investigated, making it difficult to judge the relative importance of salvage and synthesis or to design a pyrimidine-based chemotherapy. Detailed characterization of pyrimidine transport activities in bloodstream form Trypanosoma brucei brucei found that these cells express a high-affinity uracil transporter (designated TbU3) that is clearly distinct from the procyclic pyrimidine transporters. This transporter had low affinity for uridine and 2'deoxyuridine and was the sole pyrimidine transporter expressed in these cells. In addition, thymidine was taken up inefficiently through a P1-type nucleoside transporter. Of importance, the anticancer drug 5-fluorouracil was an excellent substrate for TbU3, and several 5-fluoropyrimidine analogs were investigated for uptake and trypanocidal activity; 5F-orotic acid, 5F-2'deoxyuridine displayed activity in the low micromolar range. The metabolism and mode of action of these analogs was determined using metabolomic assessments of T. brucei clonal lines adapted to high levels of these pyrimidine analogs, and of the sensitive parental strains. The analysis showed that 5-fluorouracil is incorporated into a large number of metabolites but likely exerts toxicity through incorporation into RNA. 5F-2'dUrd and 5F-2'dCtd are not incorporated into nucleic acids but act as prodrugs by inhibiting thymidylate synthase as 5F-dUMP. We present the most complete model of pyrimidine salvage in T. brucei to date, supported by genome-wide profiling of the predicted pyrimidine biosynthesis and conversion enzymes.
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Affiliation(s)
- Juma A M Ali
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom
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Ranjbarian F, Vodnala M, Vodnala SM, Rofougaran R, Thelander L, Hofer A. Trypanosoma brucei thymidine kinase is tandem protein consisting of two homologous parts, which together enable efficient substrate binding. J Biol Chem 2012; 287:17628-17636. [PMID: 22442154 DOI: 10.1074/jbc.m112.340059] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Trypanosoma brucei causes African sleeping sickness, a disease for which existing chemotherapies are limited by their toxicity or lack of efficacy. We have found that four parasites, including T. brucei, contain genes where two or four thymidine kinase (TK) sequences are fused into a single open reading frame. The T. brucei full-length enzyme as well as its two constituent parts, domain 1 and domain 2, were separately expressed and characterized. Of potential interest for nucleoside analog development, T. brucei TK was less discriminative against purines than human TK1 with the following order of catalytic efficiencies: thymidine > deoxyuridine ≫ deoxyinosine > deoxyguanosine. Proteins from the TK1 family are generally dimers or tetramers, and the quaternary structure is linked to substrate affinity. T. brucei TK was primarily monomeric but can be considered a two-domain pseudodimer. Independent kinetic analysis of the two domains showed that only domain 2 was active. It had a similar turnover number (k(cat)) as the full-length enzyme but could not self-dimerize efficiently and had a 5-fold reduced thymidine/deoxyuridine affinity. Domain 1, which lacks three conserved active site residues, can therefore be considered a covalently attached structural partner that enhances substrate binding to domain 2. A consequence of the non-catalytic role of domain 1 is that its active site residues are released from evolutionary pressure, which can be advantageous for developing new catalytic functions. In addition, nearly identical 89-bp sequences present in both domains suggest that the exchange of genetic material between them can further promote evolution.
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Affiliation(s)
- Farahnaz Ranjbarian
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Munender Vodnala
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | | | - Reza Rofougaran
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden; Department of Biochemistry, Institute of Biochemistry and Biophysics, P.O. Box 13145-1384, Tehran University, Tehran, Iran
| | - Lars Thelander
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden.
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Abstract
BACKGROUND Nucleoside/nucleobase transporters have been investigated since the 1960s. In particular, equilibrative nucleoside transporters were thought to be valuable drug targets, since they are involved in various kinds of viral and parasitic diseases as well as cancers. DISCUSSION In the postgenomic era multiple transporters, including different subtypes, have been cloned and characterized on the molecular level. In this article we summarize recent advances regarding structure, function and localization of nucleoside/nucleobase transporters as well as the pharmacological profile of selected drugs. CONCLUSION Knowledge of the different kinetic properties and structural features of nucleoside transporters can either be used for the rational design of therapeutics directly targeting the transporter itself or for the delivery of drugs using the transporter as a port of entry into the target cell. Equilibrative nucleoside transporters are of considerable pharmacological interest as drug targets for the development of drugs tailored to each patient's need for the treatment of cardiac disease, cancer and viral infections.
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Teka IA, Kazibwe AJN, El-Sabbagh N, Al-Salabi MI, Ward CP, Eze AA, Munday JC, Mäser P, Matovu E, Barrett MP, de Koning HP. The diamidine diminazene aceturate is a substrate for the high-affinity pentamidine transporter: implications for the development of high resistance levels in trypanosomes. Mol Pharmacol 2011; 80:110-6. [PMID: 21436312 DOI: 10.1124/mol.111.071555] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
African trypanosomiasis is a disease of humans and livestock in many areas south of the Sahara. Resistance to the few existing drugs is a major impediment to the control of these diseases, and we investigated how resistance to the main veterinary drug diminazene aceturate correlates with changes in drug transport in resistant strains. The strain tbat1(-/-), lacking the TbAT1/P2 aminopurine transporter implicated previously in diminazene transport, was adapted to higher levels of diminazene resistance. The resulting cell line was designated ABR and was highly cross-resistant to other diamidines and moderately resistant to cymelarsan. Procyclic trypanosomes were shown to be a convenient model to study diamidine uptake in Trypanosoma brucei brucei given the lack of TbAT1/P2 and a 10-fold higher activity of the high-affinity pentamidine transporter (HAPT1). Diminazene could be transported by HAPT1 in procyclic trypanosomes. This drug transport activity was lacking in the ABR line, as reported previously for the pentamidine-adapted line B48. The K(m) for diminazene transport in bloodstream tbat1(-/-) trypanosomes was consistent with uptake by HAPT1. Diminazene transport in ABR and B48 cells was reduced compared with tbat1(-/-), but their resistance phenotype was different: B48 displayed higher levels of resistance to pentamidine and the melaminophenyl arsenicals, whereas ABR displayed higher resistance to diminazene. These results establish a loss of HAPT1 function as a contributing factor to diminazene resistance but equally demonstrate for the first time that adaptations other than those determining the initial rates of drug uptake contribute to diamidine and arsenical resistance in African trypanosomes.
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Affiliation(s)
- Ibrahim A Teka
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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36
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Larson ET, Mudeppa DG, Gillespie JR, Mueller N, Napuli AJ, Arif JA, Ross J, Arakaki TL, Lauricella A, Detitta G, Luft J, Zucker F, Verlinde CLMJ, Fan E, Van Voorhis WC, Buckner FS, Rathod PK, Hol WGJ, Merritt EA. The crystal structure and activity of a putative trypanosomal nucleoside phosphorylase reveal it to be a homodimeric uridine phosphorylase. J Mol Biol 2010; 396:1244-59. [PMID: 20070944 DOI: 10.1016/j.jmb.2010.01.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/04/2010] [Accepted: 01/05/2010] [Indexed: 11/24/2022]
Abstract
Purine nucleoside phosphorylases (PNPs) and uridine phosphorylases (UPs) are closely related enzymes involved in purine and pyrimidine salvage, respectively, which catalyze the removal of the ribosyl moiety from nucleosides so that the nucleotide base may be recycled. Parasitic protozoa generally are incapable of de novo purine biosynthesis; hence, the purine salvage pathway is of potential therapeutic interest. Information about pyrimidine biosynthesis in these organisms is much more limited. Though all seem to carry at least a subset of enzymes from each pathway, the dependency on de novo pyrimidine synthesis versus salvage varies from organism to organism and even from one growth stage to another. We have structurally and biochemically characterized a putative nucleoside phosphorylase (NP) from the pathogenic protozoan Trypanosoma brucei and find that it is a homodimeric UP. This is the first characterization of a UP from a trypanosomal source despite this activity being observed decades ago. Although this gene was broadly annotated as a putative NP, it was widely inferred to be a purine nucleoside phosphorylase. Our characterization of this trypanosomal enzyme shows that it is possible to distinguish between PNP and UP activity at the sequence level based on the absence or presence of a characteristic UP-specificity insert. We suggest that this recognizable feature may aid in proper annotation of the substrate specificity of enzymes in the NP family.
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Affiliation(s)
- Eric T Larson
- Medical Structural Genomics of Pathogenic Protozoa Consortium, University of Washington, Seattle, WA 98195, USA
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37
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Simmons JM, Koslowsky DJ, Hausinger RP. Trypanosoma brucei brucei: thymine 7-hydroxylase-like proteins. Exp Parasitol 2009; 124:453-8. [PMID: 19945457 DOI: 10.1016/j.exppara.2009.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 11/17/2009] [Accepted: 11/23/2009] [Indexed: 01/29/2023]
Abstract
Two genes from Trypanosoma brucei brucei are predicted to encode Fe(II)- and alpha-ketoglutarate-dependent enzymes related to fungal thymine 7-hydroxylase. Transcription of the thymine hydroxylase-like genes is up-regulated in the bloodstream form of the parasite over the insect form, whereas Western blot analysis indicates more cross-reactive protein in the latter life stage. The genes were cloned, the proteins purified from Escherichia coli, and both proteins were shown to bind Fe(II) and alpha-ketoglutarate, confirming proper folding. The isolated proteins were incubated with Fe(II)- and alpha-ketoglutarate plus thymine, thymidine, and other putative substrates, but no activity was detected. Furthermore, no thymine 7-hydroxylase activity was detected in extracts of procyclic or bloodstream form cells. Although the functions of these proteins remain unknown, we conclude they are unlikely to be involved in thymine salvage.
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Affiliation(s)
- Jana M Simmons
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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38
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Castillo-Acosta VM, Estévez AM, Vidal AE, Ruiz-Perez LM, González-Pacanowska D. Depletion of dimeric all-alpha dUTPase induces DNA strand breaks and impairs cell cycle progression in Trypanosoma brucei. Int J Biochem Cell Biol 2008; 40:2901-13. [PMID: 18656547 DOI: 10.1016/j.biocel.2008.06.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 06/20/2008] [Accepted: 06/24/2008] [Indexed: 11/17/2022]
Abstract
The enzyme deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) is responsible for the control of intracellular levels of dUTP thus controlling the incorporation of uracil into DNA during replication. Trypanosomes and certain eubacteria contain a dimeric dUTP-dUDPase belonging to the recently described superfamily of all-alpha NTP pyrophosphatases which bears no resemblance with typical eukaryotic trimeric dUTPases and presents unique properties regarding substrate specificity and product inhibition. While the biological trimeric enzymes have been studied in detail and the human enzyme has been proposed as a promising novel target for anticancer chemotherapeutic strategies, little is known regarding the biological function of dimeric proteins. Here, we show that in Trypanosoma brucei, the dimeric dUTPase is a nuclear enzyme and that down-regulation of activity by RNAi greatly reduces cell proliferation and increases the intracellular levels of dUTP. Defects in growth could be partially reverted by the addition of exogenous thymidine. dUTPase-depleted cells presented hypersensitivity to methotrexate, a drug that increases the intracellular pools of dUTP, and enhanced uracil-DNA glycosylase activity, the first step in base excision repair. The knockdown of activity produces numerous DNA strand breaks and defects in both S and G2/M progression. Multiple parasites with a single enlarged nucleus were visualized together with an enhanced population of anucleated cells. We conclude that dimeric dUTPases are strongly involved in the control of dUTP incorporation and that adequate levels of enzyme are indispensable for efficient cell cycle progression and DNA replication.
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Affiliation(s)
- Víctor M Castillo-Acosta
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n 18100-Armilla, Granada, Spain
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Arakaki TL, Buckner FS, Gillespie JR, Malmquist NA, Phillips MA, Kalyuzhniy O, Luft JR, Detitta GT, Verlinde CLMJ, Van Voorhis WC, Hol WGJ, Merritt EA. Characterization of Trypanosoma brucei dihydroorotate dehydrogenase as a possible drug target; structural, kinetic and RNAi studies. Mol Microbiol 2008; 68:37-50. [PMID: 18312275 DOI: 10.1111/j.1365-2958.2008.06131.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Nucleotide biosynthesis pathways have been reported to be essential in some protozoan pathogens. Hence, we evaluated the essentiality of one enzyme in the pyrimidine biosynthetic pathway, dihydroorotate dehydrogenase (DHODH) from the eukaryotic parasite Trypanosoma brucei through gene knockdown studies. RNAi knockdown of DHODH expression in bloodstream form T. brucei did not inhibit growth in normal medium, but profoundly retarded growth in pyrimidine-depleted media or in the presence of the known pyrimidine uptake antagonist 5-fluorouracil (5-FU). These results have significant implications for the development of therapeutics to combat T. brucei infection. Specifically, a combination therapy including a T. brucei-specific DHODH inhibitor plus 5-FU may prove to be an effective therapeutic strategy. We also show that this trypanosomal enzyme is inhibited by known inhibitors of bacterial Class 1A DHODH, in distinction to the sensitivity of DHODH from human and other higher eukaryotes. This selectivity is supported by the crystal structure of the T. brucei enzyme, which is reported here at a resolution of 1.95 A. Additional research, guided by the crystal structure described herein, is needed to identify potent inhibitors of T. brucei DHODH.
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Affiliation(s)
- Tracy L Arakaki
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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Papageorgiou I, De Koning HP, Soteriadou K, Diallinas G. Kinetic and mutational analysis of the Trypanosoma brucei NBT1 nucleobase transporter expressed in Saccharomyces cerevisiae reveals structural similarities between ENT and MFS transporters. Int J Parasitol 2007; 38:641-53. [PMID: 18036529 DOI: 10.1016/j.ijpara.2007.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 10/04/2007] [Accepted: 10/08/2007] [Indexed: 02/04/2023]
Abstract
Parasitic protozoa are unable to synthesise purines de novo and thus depend on the uptake of nucleosides and nucleobases across their plasma membrane through specific transporters. A number of nucleoside and nucleobase transporters from Trypanosoma brucei brucei and Leishmania major have recently been characterised and shown to belong to the equilibrative nucleoside transporter (ENT) family. A number of studies have demonstrated the functional importance of particular transmembrane segments (TMS) in nucleoside-specific ENT proteins. TbNBT1, one of only three bona fide nucleobase-selective members of the ENT family, has previously been shown to be a high-affinity transporter for purine nucleobases and guanosine. In this study, we use the Saccharomyces cerevisiae expression system to build a biochemical model of how TbNBT1 recognises nucleobases. We next performed random in vitro and site-directed mutagenesis to identify residues critical for TbNBT1 function. The identification of residues likely to contribute to permeant binding, when combined with a structural model of TbNBT1 obtained by homology threading, yield a tentative three-dimensional model of the transporter binding site that is consistent with the binding model emerging from the biochemical data. The model strongly suggests the involvement of TMS5, TMS7 and TMS8 in TbNBT1 function. This situation is very similar to that concerning transporters of the major facilitator superfamily (MFS), one of which was used as a template for the threading. This point raises the possibility that ENT and MFS carriers, despite being considered evolutionarily distinct, might in fact share similar topologies and substrate translocations pathways.
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Affiliation(s)
- I Papageorgiou
- Department of Botany, University of Athens, Panepistimioupolis, Athens 15781, Greece
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Bellofatto V. Pyrimidine transport activities in trypanosomes. Trends Parasitol 2007; 23:187-9; discussion 190. [PMID: 17374509 DOI: 10.1016/j.pt.2007.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 02/06/2007] [Accepted: 03/08/2007] [Indexed: 01/31/2023]
Abstract
Parasites of the Trypanosomatidae family are unable to synthesize purines. Instead, they rely on their hosts to supply these necessary compounds. The article by Gudin et al. identifies three transport mechanisms of the equilibrative nucleoside transporter family by which nucleosides and nucleobases are transported in this medically important family of organisms. The work by Gudin et al. characterizes the dynamics of these transporters and points to further areas for future genetic and therapeutic experiments.
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Affiliation(s)
- Vivian Bellofatto
- Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey, Newark, NJ 07101, USA.
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