1
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Bachmaier S, Gould MK, Polatoglou E, Omelianczyk R, Brennand AE, Aloraini MA, Munday JC, Horn D, Boshart M, de Koning HP. Novel kinetoplastid-specific cAMP binding proteins identified by RNAi screening for cAMP resistance in Trypanosoma brucei. Front Cell Infect Microbiol 2023; 13:1204707. [PMID: 37475965 PMCID: PMC10354285 DOI: 10.3389/fcimb.2023.1204707] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 06/14/2023] [Indexed: 07/22/2023] Open
Abstract
Cyclic AMP signalling in trypanosomes differs from most eukaryotes due to absence of known cAMP effectors and cAMP independence of PKA. We have previously identified four genes from a genome-wide RNAi screen for resistance to the cAMP phosphodiesterase (PDE) inhibitor NPD-001. The genes were named cAMP Response Protein (CARP) 1 through 4. Here, we report an additional six CARP candidate genes from the original sample, after deep sequencing of the RNA interference target pool retrieved after NPD-001 selection (RIT-seq). The resistance phenotypes were confirmed by individual RNAi knockdown. Highest level of resistance to NPD-001, approximately 17-fold, was seen for knockdown of CARP7 (Tb927.7.4510). CARP1 and CARP11 contain predicted cyclic AMP binding domains and bind cAMP as evidenced by capture and competition on immobilised cAMP. CARP orthologues are strongly enriched in kinetoplastid species, and CARP3 and CARP11 are unique to Trypanosoma. Localization data and/or domain architecture of all CARPs predict association with the T. brucei flagellum. This suggests a crucial role of cAMP in flagellar function, in line with the cell division phenotype caused by high cAMP and the known role of the flagellum for cytokinesis. The CARP collection is a resource for discovery of unusual cAMP pathways and flagellar biology.
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Affiliation(s)
- Sabine Bachmaier
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Matthew K. Gould
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Eleni Polatoglou
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Radoslaw Omelianczyk
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Ana E. Brennand
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Maha A. Aloraini
- 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
| | - David Horn
- The Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michael Boshart
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - 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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2
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Giordani F, Khalaf AI, Gillingwater K, Munday JC, de Koning HP, Suckling CJ, Barrett MP, Scott FJ. Correction to "Novel Minor Groove Binders Cure Animal African Trypanosomiasis in an in Vivo Mouse Model". J Med Chem 2021; 64:18236. [PMID: 34854304 DOI: 10.1021/acs.jmedchem.1c01985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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3
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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: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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4
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De Araújo JS, da Silva PB, Batista MM, Peres RB, Cardoso-Santos C, Kalejaiye TD, Munday JC, De Heuvel E, Sterk GJ, Augustyns K, Salado IG, Matheeussen A, De Esch I, De Koning HP, Leurs R, Maes L, Soeiro MDNC. Evaluation of phthalazinone phosphodiesterase inhibitors with improved activity and selectivity against Trypanosoma cruzi. J Antimicrob Chemother 2021; 75:958-967. [PMID: 31860098 DOI: 10.1093/jac/dkz516] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/15/2019] [Accepted: 11/08/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, needs urgent alternative therapeutic options as the treatments currently available display severe limitations, mainly related to efficacy and toxicity. OBJECTIVES As phosphodiesterases (PDEs) have been claimed as novel targets against T. cruzi, our aim was to evaluate the biological aspects of 12 new phthalazinone PDE inhibitors against different T. cruzi strains and parasite forms relevant for human infection. METHODS In vitro trypanocidal activity of the inhibitors was assessed alone and in combination with benznidazole. Their effects on parasite ultrastructural and cAMP levels were determined. PDE mRNA levels from the different T. cruzi forms were measured by quantitative reverse transcription PCR. RESULTS Five TcrPDEs were found to be expressed in all parasite stages. Four compounds displayed strong effects against intracellular amastigotes. Against bloodstream trypomastigotes (BTs), three were at least as potent as benznidazole. In vitro combination therapy with one of the most active inhibitors on both parasite forms (NPD-040) plus benznidazole demonstrated a quite synergistic profile (xΣ FICI = 0.58) against intracellular amastigotes but no interaction (xΣ FICI = 1.27) when BTs were assayed. BTs treated with NPD-040 presented disrupted Golgi apparatus, a swollen flagellar pocket and signs of autophagy. cAMP measurements of untreated parasites showed that amastigotes have higher ability to efflux this second messenger than BTs. NPD-001 and NPD-040 increase the intracellular cAMP content in both BTs and amastigotes, which is also released into the extracellular milieu. CONCLUSIONS The findings demonstrate the potential of PDE inhibitors as anti-T. cruzi drug candidates.
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Affiliation(s)
| | | | - Marcos Meuser Batista
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Raiza Brandão Peres
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Camila Cardoso-Santos
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Titilola D Kalejaiye
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Jane C Munday
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Erik De Heuvel
- Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines & Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Geert Jan Sterk
- Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines & Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Koen Augustyns
- Laboratory of Medicinal Chemistry, University of Antwerp, Antwerp, Belgium
| | - Irene G Salado
- Laboratory of Medicinal Chemistry, University of Antwerp, Antwerp, Belgium
| | - An Matheeussen
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Iwan De Esch
- Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines & Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Harry P De Koning
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Rob Leurs
- Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines & Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Louis Maes
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
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5
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Carruthers LV, Munday JC, Ebiloma GU, Steketee P, Jayaraman S, Campagnaro GD, Ungogo MA, Lemgruber L, Donachie AM, Rowan TG, Peter R, Morrison LJ, Barrett MP, De Koning HP. Diminazene resistance in Trypanosoma congolense is not caused by reduced transport capacity but associated with reduced mitochondrial membrane potential. Mol Microbiol 2021; 116:564-588. [PMID: 33932053 DOI: 10.1111/mmi.14733] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/14/2021] [Accepted: 04/27/2021] [Indexed: 01/27/2023]
Abstract
Trypanosoma congolense is a principal agent causing livestock trypanosomiasis in Africa, costing developing economies billions of dollars and undermining food security. Only the diamidine diminazene and the phenanthridine isometamidium are regularly used, and resistance is widespread but poorly understood. We induced stable diminazene resistance in T. congolense strain IL3000 in vitro. There was no cross-resistance with the phenanthridine drugs, melaminophenyl arsenicals, oxaborole trypanocides, or with diamidine trypanocides, except the close analogs DB829 and DB75. Fluorescence microscopy showed that accumulation of DB75 was inhibited by folate. Uptake of [3 H]-diminazene was slow with low affinity and partly but reciprocally inhibited by folate and by competing diamidines. Expression of T. congolense folate transporters in diminazene-resistant Trypanosoma brucei brucei significantly sensitized the cells to diminazene and DB829, but not to oxaborole AN7973. However, [3 H]-diminazene transport studies, whole-genome sequencing, and RNA-seq found no major changes in diminazene uptake, folate transporter sequence, or expression. Instead, all resistant clones displayed a moderate reduction in the mitochondrial membrane potential Ψm. We conclude that diminazene uptake in T. congolense proceed via multiple low affinity mechanisms including folate transporters; while resistance is associated with a reduction in Ψm it is unclear whether this is the primary cause of the resistance.
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Affiliation(s)
- Lauren V Carruthers
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Jane C Munday
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,School of Health and Life Sciences, Teesside University, Middlesbrough, UK
| | - Pieter Steketee
- Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, UK
| | - Siddharth Jayaraman
- Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, UK
| | - Gustavo D Campagnaro
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Marzuq A Ungogo
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Leandro Lemgruber
- Glasgow Imaging Facility, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Anne-Marie Donachie
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Tim G Rowan
- Global Alliance for Livestock Veterinary Medicine, Pentlands Science Park, Edinburgh, UK
| | - Rose Peter
- Global Alliance for Livestock Veterinary Medicine, Pentlands Science Park, Edinburgh, UK
| | - Liam J Morrison
- Roslin Institute, Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Edinburgh, UK
| | - Michael P Barrett
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,Wellcome Centre for Integrative Parasitology, University of Glasgow, 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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6
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Alghamdi AH, Munday JC, Campagnaro GD, Gurvic D, Svensson F, Okpara CE, Kumar A, Quintana J, Martin Abril ME, Milić P, Watson L, Paape D, Settimo L, Dimitriou A, Wielinska J, Smart G, Anderson LF, Woodley CM, Kelly SPY, Ibrahim HM, Hulpia F, Al-Salabi MI, Eze AA, Sprenger T, Teka IA, Gudin S, Weyand S, Field M, Dardonville C, Tidwell RR, Carrington M, O'Neill P, Boykin DW, Zachariae U, De Koning HP. Positively selected modifications in the pore of TbAQP2 allow pentamidine to enter Trypanosoma brucei. eLife 2020; 9:56416. [PMID: 32762841 PMCID: PMC7473772 DOI: 10.7554/elife.56416] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 08/06/2020] [Indexed: 11/25/2022] Open
Abstract
Mutations in the Trypanosoma brucei aquaporin AQP2 are associated with resistance to pentamidine and melarsoprol. We show that TbAQP2 but not TbAQP3 was positively selected for increased pore size from a common ancestor aquaporin. We demonstrate that TbAQP2’s unique architecture permits pentamidine permeation through its central pore and show how specific mutations in highly conserved motifs affect drug permeation. Introduction of key TbAQP2 amino acids into TbAQP3 renders the latter permeable to pentamidine. Molecular dynamics demonstrates that permeation by dicationic pentamidine is energetically favourable in TbAQP2, driven by the membrane potential, although aquaporins are normally strictly impermeable for ionic species. We also identify the structural determinants that make pentamidine a permeant although most other diamidine drugs are excluded. Our results have wide-ranging implications for optimising antitrypanosomal drugs and averting cross-resistance. Moreover, these new insights in aquaporin permeation may allow the pharmacological exploitation of other members of this ubiquitous gene family. African sleeping sickness is a potentially deadly illness caused by the parasite Trypanosoma brucei. The disease is treatable, but many of the current treatments are old and are becoming increasingly ineffective. For instance, resistance is growing against pentamidine, a drug used in the early stages in the disease, as well as against melarsoprol, which is deployed when the infection has progressed to the brain. Usually, cases resistant to pentamidine are also resistant to melarsoprol, but it is still unclear why, as the drugs are chemically unrelated. Studies have shown that changes in a water channel called aquaglyceroporin 2 (TbAQP2) contribute to drug resistance in African sleeping sickness; this suggests that it plays a role in allowing drugs to kill the parasite. This molecular ‘drain pipe’ extends through the surface of T. brucei, and should allow only water and a molecule called glycerol in and out of the cell. In particular, the channel should be too narrow to allow pentamidine or melarsoprol to pass through. One possibility is that, in T. brucei, the TbAQP2 channel is abnormally wide compared to other members of its family. Alternatively, pentamidine and melarsoprol may only bind to TbAQP2, and then ‘hitch a ride’ when the protein is taken into the parasite as part of the natural cycle of surface protein replacement. Alghamdi et al. aimed to tease out these hypotheses. Computer models of the structure of the protein were paired with engineered changes in the key areas of the channel to show that, in T. brucei, TbAQP2 provides a much broader gateway into the cell than observed for similar proteins. In addition, genetic analysis showed that this version of TbAQP2 has been actively selected for during the evolution process of T. brucei. This suggests that the parasite somehow benefits from this wider aquaglyceroporin variant. This is a new resistance mechanism, and it is possible that aquaglyceroporins are also larger than expected in other infectious microbes. The work by Alghamdi et al. therefore provides insight into how other germs may become resistant to drugs.
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Affiliation(s)
- Ali H Alghamdi
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Jane C Munday
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | | | - Dominik Gurvic
- Computational Biology Centre for Translational and Interdisciplinary Research, University of Dundee, Dundee, United Kingdom
| | - Fredrik Svensson
- IOTA Pharmaceuticals Ltd, St Johns Innovation Centre, Cambridge, United Kingdom
| | - Chinyere E Okpara
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Arvind Kumar
- Chemistry Department, Georgia State University, Atlanta, United States
| | - Juan Quintana
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | | | - Patrik Milić
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Laura Watson
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Daniel Paape
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Luca Settimo
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Anna Dimitriou
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Joanna Wielinska
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Graeme Smart
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Laura F Anderson
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | | | - Siu Pui Ying Kelly
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Hasan Ms Ibrahim
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Fabian Hulpia
- Laboratory for Medicinal Chemistry, University of Ghent, Ghent, Belgium
| | - Mohammed I Al-Salabi
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Anthonius A Eze
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Teresa Sprenger
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ibrahim A Teka
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Simon Gudin
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Simone Weyand
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mark Field
- School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | | | - Richard R Tidwell
- Department of Pathology and Lab Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Paul O'Neill
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - David W Boykin
- Chemistry Department, Georgia State University, Atlanta, United States
| | - Ulrich Zachariae
- Computational Biology Centre for Translational and Interdisciplinary Research, University of Dundee, Dundee, United Kingdom
| | - Harry P De Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
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7
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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8
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Giordani F, Khalaf AI, Gillingwater K, Munday JC, de Koning HP, Suckling CJ, Barrett MP, Scott FJ. Novel Minor Groove Binders Cure Animal African Trypanosomiasis in an in Vivo Mouse Model. J Med Chem 2019; 62:3021-3035. [DOI: 10.1021/acs.jmedchem.8b01847] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
| | - Abedawn I. Khalaf
- Department of Pure and Applied Chemistry, WestCHEM, University of Strathclyde, Glasgow G1 1XL, U.K
| | - Kirsten Gillingwater
- Parasite Chemotherapy, Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel 4051, Switzerland
- University of Basel, Basel 4001, Switzerland
| | | | | | - Colin J. Suckling
- Department of Pure and Applied Chemistry, WestCHEM, University of Strathclyde, Glasgow G1 1XL, U.K
| | | | - Fraser J. Scott
- Department of Biological and Geographical Sciences, School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH, U.K
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9
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Botros SS, William S, Sabra ANA, El-Lakkany NM, Seif El-Din SH, García-Rubia A, Sebastián-Pérez V, Blaazer AR, de Heuvel E, Sijm M, Zheng Y, Salado IG, Munday JC, Maes L, de Esch IJP, Sterk GJ, Augustyns K, Leurs R, Gil C, De Koning HP. Screening of a PDE-focused library identifies imidazoles with in vitro and in vivo antischistosomal activity. Int J Parasitol Drugs Drug Resist 2019; 9:35-43. [PMID: 30669086 PMCID: PMC6350229 DOI: 10.1016/j.ijpddr.2019.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/10/2019] [Accepted: 01/13/2019] [Indexed: 01/10/2023]
Abstract
We report the evaluation of 265 compounds from a PDE-focused library for their antischistosomal activity, assessed in vitro using Schistosoma mansoni. Of the tested compounds, 171 (64%) displayed selective in vitro activity, with 16 causing worm hypermotility/spastic contractions and 41 inducing various degrees of worm killing at 100 μM, with the surviving worms displaying sluggish movement, worm unpairing and complete absence of eggs. The compounds that did not affect worm viability (n = 72) induced a complete cessation of ovipositing. 82% of the compounds had an impact on male worms whereas female worms were barely affected. In vivo evaluation in S. mansoni-infected mice with the in vitro 'hit' NPD-0274 at 20 mg/kg/day orally for 5 days resulted in worm burden reductions of 29% and intestinal tissue egg load reduction of 35% at 10 days post-treatment. Combination of praziquantel (PZQ) at 10 mg/kg/day for 5 days with NPD-0274 or NPD-0298 resulted in significantly higher worm killing than PZQ alone, as well as a reduction in intestinal tissue egg load, disappearance of immature eggs and an increase in the number of dead eggs.
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Affiliation(s)
- Sanaa S Botros
- Pharmacology Department, Theodor Bilharz Research Institute, Warrak El-Hadar, Imbaba, P.O. Box 30, Giza, 12411, Egypt
| | - Samia William
- Parasitology Department, Theodor Bilharz Research Institute, Warrak El-Hadar, Imbaba, P.O. Box 30, Giza, 12411, Egypt
| | - Abdel-Nasser A Sabra
- Pharmacology Department, Theodor Bilharz Research Institute, Warrak El-Hadar, Imbaba, P.O. Box 30, Giza, 12411, Egypt
| | - Naglaa M El-Lakkany
- Pharmacology Department, Theodor Bilharz Research Institute, Warrak El-Hadar, Imbaba, P.O. Box 30, Giza, 12411, Egypt
| | - Sayed H Seif El-Din
- Pharmacology Department, Theodor Bilharz Research Institute, Warrak El-Hadar, Imbaba, P.O. Box 30, Giza, 12411, Egypt
| | | | | | - Antoni R Blaazer
- Medicinal Chemistry Vrije Universiteit Amsterdam (VUA), the Netherlands
| | - Erik de Heuvel
- Medicinal Chemistry Vrije Universiteit Amsterdam (VUA), the Netherlands
| | - Maarten Sijm
- Medicinal Chemistry Vrije Universiteit Amsterdam (VUA), the Netherlands
| | - Yang Zheng
- Medicinal Chemistry Vrije Universiteit Amsterdam (VUA), the Netherlands
| | | | - Jane C Munday
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | | | - Iwan J P de Esch
- Medicinal Chemistry Vrije Universiteit Amsterdam (VUA), the Netherlands
| | - Geert J Sterk
- Medicinal Chemistry Vrije Universiteit Amsterdam (VUA), the Netherlands
| | | | - Rob Leurs
- Medicinal Chemistry Vrije Universiteit Amsterdam (VUA), the Netherlands
| | - Carmen Gil
- Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, Spain
| | - Harry P De Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK.
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10
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Sebastián-Pérez V, Hendrickx S, Munday JC, Kalejaiye T, Martínez A, Campillo NE, de Koning H, Caljon G, Maes L, Gil C. Cyclic Nucleotide-Specific Phosphodiesterases as Potential Drug Targets for Anti-Leishmania Therapy. Antimicrob Agents Chemother 2018; 62:e00603-18. [PMID: 30104270 PMCID: PMC6153811 DOI: 10.1128/aac.00603-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/05/2018] [Indexed: 01/22/2023] Open
Abstract
The available treatments for leishmaniasis are less than optimal due to inadequate efficacy, toxic side effects, and the emergence of resistant strains, clearly endorsing the urgent need for discovery and development of novel drug candidates. Ideally, these should act via an alternative mechanism of action to avoid cross-resistance with the current drugs. As cyclic nucleotide-specific phosphodiesterases (PDEs) of Leishmania major have been postulated as putative drug targets, a series of potential inhibitors of Leishmania PDEs were explored. Several displayed potent and selective in vitro activity against L. infantum intracellular amastigotes. One imidazole derivative, compound 35, was shown to reduce the parasite loads in vivo and to increase the cellular cyclic AMP (cAMP) level at in a dose-dependent manner at just 2× and 5× the 50% inhibitory concentration (IC50), indicating a correlation between antileishmanial activity and increased cellular cAMP levels. Docking studies and molecular dynamics simulations pointed to imidazole 35 exerting its activity through PDE inhibition. This study establishes for the first time that inhibition of cAMP PDEs can potentially be exploited for new antileishmanial chemotherapy.
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Affiliation(s)
| | - Sarah Hendrickx
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Jane C Munday
- Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Titilola Kalejaiye
- Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Ana Martínez
- Centro de Investigaciones Biológicas (CIB, CSIC), Madrid, Spain
| | | | - Harry de Koning
- Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Guy Caljon
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Louis Maes
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
| | - Carmen Gil
- Centro de Investigaciones Biológicas (CIB, CSIC), Madrid, Spain
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11
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Blaazer AR, Singh AK, de Heuvel E, Edink E, Orrling KM, Veerman JJN, van den Bergh T, Jansen C, Balasubramaniam E, Mooij WJ, Custers H, Sijm M, Tagoe DNA, Kalejaiye TD, Munday JC, Tenor H, Matheeussen A, Wijtmans M, Siderius M, de Graaf C, Maes L, de Koning HP, Bailey DS, Sterk GJ, de Esch IJP, Brown DG, Leurs R. Targeting a Subpocket in Trypanosoma brucei Phosphodiesterase B1 (TbrPDEB1) Enables the Structure-Based Discovery of Selective Inhibitors with Trypanocidal Activity. J Med Chem 2018; 61:3870-3888. [PMID: 29672041 PMCID: PMC5949723 DOI: 10.1021/acs.jmedchem.7b01670] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
Several trypanosomatid
cyclic nucleotide phosphodiesterases (PDEs)
possess a unique, parasite-specific cavity near the ligand-binding
region that is referred to as the P-pocket. One of these enzymes, Trypanosoma brucei PDE B1 (TbrPDEB1), is considered a drug
target for the treatment of African sleeping sickness. Here, we elucidate
the molecular determinants of inhibitor binding and reveal that the
P-pocket is amenable to directed design. By iterative cycles of design,
synthesis, and pharmacological evaluation and by elucidating the structures
of inhibitor-bound TbrPDEB1, hPDE4B, and hPDE4D complexes, we have
developed 4a,5,8,8a-tetrahydrophthalazinones as the first selective
TbrPDEB1 inhibitor series. Two of these, 8 (NPD-008)
and 9 (NPD-039), were potent (Ki = 100 nM) TbrPDEB1 inhibitors with antitrypanosomal effects
(IC50 = 5.5 and 6.7 μM, respectively). Treatment
of parasites with 8 caused an increase in intracellular
cyclic adenosine monophosphate (cAMP) levels and severe disruption
of T. brucei cellular organization, chemically validating
trypanosomal PDEs as therapeutic targets in trypanosomiasis.
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Affiliation(s)
- Antoni R Blaazer
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Abhimanyu K Singh
- School of Biosciences , University of Kent , Canterbury CT2 7NJ , U.K
| | - Erik de Heuvel
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Ewald Edink
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Kristina M Orrling
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | | | | | - Chimed Jansen
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | | | - Wouter J Mooij
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Hans Custers
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Maarten Sijm
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Daniel N A Tagoe
- Institute of Infection, Immunity and Inflammation , University of Glasgow , Glasgow G12 8TA , U.K
| | - Titilola D Kalejaiye
- Institute of Infection, Immunity and Inflammation , University of Glasgow , Glasgow G12 8TA , U.K
| | - Jane C Munday
- Institute of Infection, Immunity and Inflammation , University of Glasgow , Glasgow G12 8TA , U.K
| | | | - An Matheeussen
- Laboratory for Microbiology, Parasitology and Hygiene , University of Antwerp , 2610 Wilrijk , Belgium
| | - Maikel Wijtmans
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Marco Siderius
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Chris de Graaf
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Louis Maes
- Laboratory for Microbiology, Parasitology and Hygiene , University of Antwerp , 2610 Wilrijk , Belgium
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation , University of Glasgow , Glasgow G12 8TA , U.K
| | | | - Geert Jan Sterk
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - Iwan J P de Esch
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
| | - David G Brown
- School of Biosciences , University of Kent , Canterbury CT2 7NJ , U.K
| | - Rob Leurs
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules, Medicines and Systems , Vrije Universiteit Amsterdam , 1081 HZ Amsterdam , The Netherlands
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12
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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] [What about the content of this article? (0)] [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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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Graf FE, Ludin P, Arquint C, Schmidt RS, Schaub N, Kunz Renggli C, Munday JC, Krezdorn J, Baker N, Horn D, Balmer O, Caccone A, de Koning HP, Mäser P. Comparative genomics of drug resistance in Trypanosoma brucei rhodesiense. Cell Mol Life Sci 2016; 73:3387-400. [PMID: 26973180 PMCID: PMC4967103 DOI: 10.1007/s00018-016-2173-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 03/01/2016] [Indexed: 12/02/2022]
Abstract
Trypanosoma brucei rhodesiense is one of the causative agents of human sleeping sickness, a fatal disease that is transmitted by tsetse flies and restricted to Sub-Saharan Africa. Here we investigate two independent lines of T. b. rhodesiense that have been selected with the drugs melarsoprol and pentamidine over the course of 2 years, until they exhibited stable cross-resistance to an unprecedented degree. We apply comparative genomics and transcriptomics to identify the underlying mutations. Only few mutations have become fixed during selection. Three genes were affected by mutations in both lines: the aminopurine transporter AT1, the aquaporin AQP2, and the RNA-binding protein UBP1. The melarsoprol-selected line carried a large deletion including the adenosine transporter gene AT1, whereas the pentamidine-selected line carried a heterozygous point mutation in AT1, G430R, which rendered the transporter non-functional. Both resistant lines had lost AQP2, and both lines carried the same point mutation, R131L, in the RNA-binding motif of UBP1. The finding that concomitant deletion of the known resistance genes AT1 and AQP2 in T. b. brucei failed to phenocopy the high levels of resistance of the T. b. rhodesiense mutants indicated a possible role of UBP1 in melarsoprol–pentamidine cross-resistance. However, homozygous in situ expression of UBP1-Leu131 in T. b. brucei did not affect the sensitivity to melarsoprol or pentamidine.
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Affiliation(s)
- Fabrice E Graf
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Philipp Ludin
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Christian Arquint
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Remo S Schmidt
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Nadia Schaub
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Christina Kunz Renggli
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Jane C Munday
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jessica Krezdorn
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Nicola Baker
- Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK.,The University of Kent, Canterbury, Kent, CT2 7NZ, UK
| | - David Horn
- Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Oliver Balmer
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,University of Basel, 4000, Basel, Switzerland
| | - Adalgisa Caccone
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland. .,University of Basel, 4000, Basel, Switzerland.
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15
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Graf FE, Baker N, Munday JC, de Koning HP, Horn D, Mäser P. Chimerization at the AQP2-AQP3 locus is the genetic basis of melarsoprol-pentamidine cross-resistance in clinical Trypanosoma brucei gambiense isolates. Int J Parasitol Drugs Drug Resist 2015; 5:65-8. [PMID: 26042196 PMCID: PMC4443405 DOI: 10.1016/j.ijpddr.2015.04.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 01/12/2023]
Abstract
Expression of AQP2 restores drug susceptibility in a resistant Trypanosoma brucei gambiense isolate. The AQP2/3 chimera from the resistant isolate does not complement AQP2 deletion. Hence AQP2/3 chimerization accompanied by loss of AQP2 is the cause of drug resistance.
Aquaglyceroporin-2 is a known determinant of melarsoprol–pentamidine cross-resistance in Trypanosoma brucei brucei laboratory strains. Recently, chimerization at the AQP2–AQP3 tandem locus was described from melarsoprol–pentamidine cross-resistant Trypanosoma brucei gambiense isolates from sleeping sickness patients in the Democratic Republic of the Congo. Here, we demonstrate that reintroduction of wild-type AQP2 into one of these isolates fully restores drug susceptibility while expression of the chimeric AQP2/3 gene in aqp2–aqp3 null T. b. brucei does not. This proves that AQP2–AQP3 chimerization is the cause of melarsoprol–pentamidine cross-resistance in the T. b. gambiense isolates.
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Affiliation(s)
- Fabrice E Graf
- Swiss Tropical and Public Health Institute, CH-4051 Basel, Switzerland ; University of Basel, CH-4000 Basel, Switzerland
| | - Nicola Baker
- Biological Chemistry & Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Jane C Munday
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - David Horn
- Biological Chemistry & Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, CH-4051 Basel, Switzerland ; University of Basel, CH-4000 Basel, Switzerland
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16
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Munday JC, Tagoe DNA, Eze AA, Krezdorn JAM, Rojas López KE, Alkhaldi AAM, McDonald F, Still J, Alzahrani KJ, Settimo L, De Koning HP. Functional analysis of drug resistance-associated mutations in the Trypanosoma brucei adenosine transporter 1 (TbAT1) and the proposal of a structural model for the protein. Mol Microbiol 2015; 96:887-900. [PMID: 25708978 PMCID: PMC4755147 DOI: 10.1111/mmi.12979] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2015] [Indexed: 02/01/2023]
Abstract
The Trypanosoma brucei aminopurine transporter P2/TbAT1 has long been implicated in the transport of, and resistance to, the diamidine and melaminophenyl arsenical classes of drugs that form the backbone of the pharmacopoeia against African trypanosomiasis. Genetic alterations including deletions and single nucleotide polymorphisms (SNPs) have been observed in numerous strains and clinical isolates. Here, we systematically investigate each reported mutation and assess their effects on transporter function after expression in a tbat1−/−T. brucei line. Out of a set of six reported SNPs from a reported ‘resistance allele’, none significantly impaired sensitivity to pentamidine, diminazene or melarsoprol, relative to the TbAT1‐WT allele, although several combinations, and the deletion of the codon for residue F316, resulted in highly significant impairment. These combinations of SNPs, and ΔF316, also strongly impaired the uptake of [3H]‐adenosine and [3H]‐diminazene, identical to the tbat1−/− control. The TbAT1 protein model predicted that residues F19, D140 and F316 interact with the substrate of the transporter. Mutation of D140 to alanine resulted in an inactive transporter, whereas the mutation F19A produced a transporter with a slightly increased affinity for [3H]‐diminazene but reduced the uptake rate. The results presented here validate earlier hypotheses of drug binding motifs for TbAT1.
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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, Glasgow, G12 8TA, UK.,Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, UK
| | - Daniel N A Tagoe
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Department of Laboratory Technology, University of Cape Coast, Cape Coast, Ghana
| | - Anthonius A Eze
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Department of Medical Biochemistry, College of Medicine, University of Nigeria, Enugu Campus, Enugu, Nigeria
| | - Jessica A M Krezdorn
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Karla E Rojas López
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Abdulsalam A M Alkhaldi
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Department of Biology, College of Science, Aljouf University, Sakaka, Saudi Arabia
| | - Fiona McDonald
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jennifer Still
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Khalid J Alzahrani
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Faculty of Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Luca Settimo
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Department of Chemistry and Chemical Biology, 417 Egan Research Center, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA
| | - Harry P De Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
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Munday JC, Settimo L, de Koning HP. Transport proteins determine drug sensitivity and resistance in a protozoan parasite, Trypanosoma brucei. Front Pharmacol 2015; 6:32. [PMID: 25814953 PMCID: PMC4356943 DOI: 10.3389/fphar.2015.00032] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 02/05/2015] [Indexed: 12/02/2022] Open
Abstract
Drug resistance in pathogenic protozoa is very often caused by changes to the ‘transportome’ of the parasites. In Trypanosoma brucei, several transporters have been implicated in uptake of the main classes of drugs, diamidines and melaminophenyl arsenicals. The resistance mechanism had been thought to be due to loss of a transporter known to carry both types of agents: the aminopurine transporter P2, encoded by the gene TbAT1. However, although loss of P2 activity is well-documented as the cause of resistance to the veterinary diamidine diminazene aceturate (DA; Berenil®), cross-resistance between the human-use arsenical melarsoprol and the diamidine pentamidine (melarsoprol/pentamidine cross resistance, MPXR) is the result of loss of a separate high affinity pentamidine transporter (HAPT1). A genome-wide RNAi library screen for resistance to pentamidine, published in 2012, gave the key to the genetic identity of HAPT1 by linking the phenomenon to a locus that contains the closely related T. brucei aquaglyceroporin genes TbAQP2 and TbAQP3. Further analysis determined that knockdown of only one pore, TbAQP2, produced the MPXR phenotype. TbAQP2 is an unconventional aquaglyceroporin with unique residues in the “selectivity region” of the pore, and it was found that in several MPXR lab strains the WT gene was either absent or replaced by a chimeric protein, recombined with parts of TbAQP3. Importantly, wild-type AQP2 was also absent in field isolates of T. b. gambiense, correlating with the outcome of melarsoprol treatment. Expression of a wild-type copy of TbAQP2 in even the most resistant strain completely reversed MPXR and re-introduced HAPT1 function and transport kinetics. Expression of TbAQP2 in Leishmania mexicana introduced a pentamidine transport activity indistinguishable from HAPT1. Although TbAQP2 has been shown to function as a classical aquaglyceroporin it is now clear that it is also a high affinity drug transporter, HAPT1. We discuss here a possible structural rationale for this remarkable ability.
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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 Glasgow, UK
| | - Luca Settimo
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow Glasgow, UK ; Department of Chemistry and Chemical Biology, Northeastern University Boston, MA, USA
| | - 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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Munday JC, Eze AA, Baker N, Glover L, Clucas C, Aguinaga Andrés D, Natto MJ, Teka IA, McDonald J, Lee RS, Graf FE, Ludin P, Burchmore RJS, Turner CMR, Tait A, MacLeod A, Mäser P, Barrett MP, Horn D, De Koning HP. Trypanosoma brucei aquaglyceroporin 2 is a high-affinity transporter for pentamidine and melaminophenyl arsenic drugs and the main genetic determinant of resistance to these drugs. J Antimicrob Chemother 2013; 69:651-63. [PMID: 24235095 PMCID: PMC3922157 DOI: 10.1093/jac/dkt442] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Objectives Trypanosoma brucei drug transporters include the TbAT1/P2 aminopurine transporter and the high-affinity pentamidine transporter (HAPT1), but the genetic identity of HAPT1 is unknown. We recently reported that loss of T. brucei aquaglyceroporin 2 (TbAQP2) caused melarsoprol/pentamidine cross-resistance (MPXR) in these parasites and the current study aims to delineate the mechanism by which this occurs. Methods The TbAQP2 loci of isogenic pairs of drug-susceptible and MPXR strains of T. brucei subspecies were sequenced. Drug susceptibility profiles of trypanosome strains were correlated with expression of mutated TbAQP2 alleles. Pentamidine transport was studied in T. brucei subspecies expressing TbAQP2 variants. Results All MPXR strains examined contained TbAQP2 deletions or rearrangements, regardless of whether the strains were originally adapted in vitro or in vivo to arsenicals or to pentamidine. The MPXR strains and AQP2 knockout strains had lost HAPT1 activity. Reintroduction of TbAQP2 in MPXR trypanosomes restored susceptibility to the drugs and reinstated HAPT1 activity, but did not change the activity of TbAT1/P2. Expression of TbAQP2 sensitized Leishmania mexicana promastigotes 40-fold to pentamidine and >1000-fold to melaminophenyl arsenicals and induced a high-affinity pentamidine transport activity indistinguishable from HAPT1 by Km and inhibitor profile. Grafting the TbAQP2 selectivity filter amino acid residues onto a chimeric allele of AQP2 and AQP3 partly restored susceptibility to pentamidine and an arsenical. Conclusions TbAQP2 mediates high-affinity uptake of pentamidine and melaminophenyl arsenicals in trypanosomes and TbAQP2 encodes the previously reported HAPT1 activity. This finding establishes TbAQP2 as an important drug transporter.
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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, Glasgow, UK
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Gould MK, Bachmaier S, Ali JAM, Alsford S, Tagoe DNA, Munday JC, Schnaufer AC, Horn D, Boshart M, de Koning HP. Cyclic AMP effectors in African trypanosomes revealed by genome-scale RNA interference library screening for resistance to the phosphodiesterase inhibitor CpdA. Antimicrob Agents Chemother 2013; 57:4882-93. [PMID: 23877697 PMCID: PMC3811416 DOI: 10.1128/aac.00508-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 07/15/2013] [Indexed: 12/11/2022] Open
Abstract
One of the most promising new targets for trypanocidal drugs to emerge in recent years is the cyclic AMP (cAMP) phosphodiesterase (PDE) activity encoded by TbrPDEB1 and TbrPDEB2. These genes were genetically confirmed as essential, and a high-affinity inhibitor, CpdA, displays potent antitrypanosomal activity. To identify effectors of the elevated cAMP levels resulting from CpdA action and, consequently, potential sites for adaptations giving resistance to PDE inhibitors, resistance to the drug was induced. Selection of mutagenized trypanosomes resulted in resistance to CpdA as well as cross-resistance to membrane-permeable cAMP analogues but not to currently used trypanocidal drugs. Resistance was not due to changes in cAMP levels or in PDEB genes. A second approach, a genome-wide RNA interference (RNAi) library screen, returned four genes giving resistance to CpdA upon knockdown. Validation by independent RNAi strategies confirmed resistance to CpdA and suggested a role for the identified cAMP Response Proteins (CARPs) in cAMP action. CARP1 is unique to kinetoplastid parasites and has predicted cyclic nucleotide binding-like domains, and RNAi repression resulted in >100-fold resistance. CARP2 and CARP4 are hypothetical conserved proteins associated with the eukaryotic flagellar proteome or with flagellar function, with an orthologue of CARP4 implicated in human disease. CARP3 is a hypothetical protein, unique to Trypanosoma. CARP1 to CARP4 likely represent components of a novel cAMP signaling pathway in the parasite. As cAMP metabolism is validated as a drug target in Trypanosoma brucei, cAMP effectors highly divergent from the mammalian host, such as CARP1, lend themselves to further pharmacological development.
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Affiliation(s)
- Matthew K. Gould
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Centre for Immunity, Infection & Evolution, Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Sabine Bachmaier
- Biocenter, Section Genetics, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Juma A. M. Ali
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sam Alsford
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Daniel N. A. Tagoe
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Jane C. Munday
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Achim C. Schnaufer
- Centre for Immunity, Infection & Evolution, Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - David Horn
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Michael Boshart
- Biocenter, Section Genetics, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Harry P. de Koning
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Munday JC, Rojas López KE, Eze AA, Delespaux V, Van Den Abbeele J, Rowan T, Barrett MP, Morrison LJ, de Koning HP. Functional expression of TcoAT1 reveals it to be a P1-type nucleoside transporter with no capacity for diminazene uptake. Int J Parasitol Drugs Drug Resist 2013; 3:69-76. [PMID: 24533295 PMCID: PMC3862423 DOI: 10.1016/j.ijpddr.2013.01.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 01/19/2013] [Accepted: 01/23/2013] [Indexed: 11/26/2022]
Abstract
It has long been established that the Trypanosoma brucei TbAT1/P2 aminopurine transporter is involved in the uptake of diamidine and arsenical drugs including pentamidine, diminazene aceturate and melarsoprol. Accordingly, it was proposed that the closest Trypanosoma congolense paralogue, TcoAT1, might perform the same function in this parasite, and an apparent correlation between a Single Nucleotide Polymorphism (SNP) in that gene and diminazene tolerance was reported for the strains examined. Here, we report the functional cloning and expression of TcoAT1 and show that in fact it is the syntenic homologue of another T. brucei gene of the same Equilibrative Nucleoside Transporter (ENT) family: TbNT10. The T. congolense genome does not seem to contain a syntenic equivalent to TbAT1. Two TcoAT1 alleles, differentiated by three independent SNPs, were expressed in the T. brucei clone B48, a TbAT1-null strain that further lacks the High Affinity Pentamidine Transporter (HAPT1); TbAT1 was also expressed as a control. The TbAT1 and TcoAT1 transporters were functional and increased sensitivity to cytotoxic nucleoside analogues. However, only TbAT1 increased sensitivity to diamidines and to cymelarsan. Uptake of [3H]-diminazene was detectable only in the B48 cells expressing TbAT1 but not TcoAT1, whereas uptake of [3H]-inosine was increased by both TcoAT1 alleles but not by TbAT1. Uptake of [3H]-adenosine was increased by all three ENT genes. We conclude that TcoAT1 is a P1-type purine nucleoside transporter and the syntenic equivalent to the previously characterised TbNT10; it does not mediate diminazene uptake and is therefore unlikely to play a role in diminazene resistance in T. congolense.
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Affiliation(s)
- Jane C Munday
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom ; Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Karla E Rojas López
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anthonius A Eze
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Vincent Delespaux
- Institute of Tropical Medicine, Nationalestraat 155, B-2000 Antwerp, Belgium
| | - Jan Van Den Abbeele
- Institute of Tropical Medicine, Nationalestraat 155, B-2000 Antwerp, Belgium
| | - Tim Rowan
- GALVmed, Pentlands Science Park, Bush Loan, Edinburgh, United Kingdom
| | - Michael P Barrett
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom ; 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 ; Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom ; Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, 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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Munday JC, McLuskey K, Brown E, Coombs GH, Mottram JC. Oligopeptidase B deficient mutants of Leishmania major. Mol Biochem Parasitol 2010; 175:49-57. [PMID: 20883728 DOI: 10.1016/j.molbiopara.2010.09.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 08/27/2010] [Accepted: 09/11/2010] [Indexed: 01/02/2023]
Abstract
Oligopeptidase B is a clan SC, family S9 serine peptidase found in gram positive bacteria, plants and trypanosomatids. Evidence suggests it is a virulence factor and thus therapeutic target in both Trypanosoma cruzi and T. brucei, but little is known about its function in Leishmania. In this study L. major OPB-deficient mutants (Δopb) were created. These grew normally as promastigotes, had a small deficiency in their ability to undergo differentiation to metacyclic promastigotes, were significantly less able to infect and survive within macrophages in vitro, but were virulent to mice. These data suggest that L. major OPB itself is not an important virulence factor, indicating functional differences between trypanosomes and Leishmania in their interaction with the mammalian host. The possibility that an OPB-like enzyme (designated OPB2) in L. major might compensate for the loss of OPB in Δopb was investigated via by mapping its sequence onto the 1.6Å structure of L. major OPB. This suggested that the residues involved in the S1 and S2 subsites of OPB2 are identical to OPB and hence the substrate specificity would be similar. Consequently there may be redundancy between the two enzymes.
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Affiliation(s)
- Jane C Munday
- 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, Scotland, UK
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Munday JC. Appreciation for your editorial. MedGenMed 2001; 3:13. [PMID: 11976609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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Mohanty P, Munday JC. Time-dependent quenching of chlorophyll a fluorescence from (pigment) system II by (pigment) system I of photosynthesis in Chlorella. Biochim Biophys Acta 1970; 223:198-200. [PMID: 5484052 DOI: 10.1016/0005-2728(70)90145-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Munday JC. Light-induced changes in the fluorescence yield of chlorophyll A in vivo. 3. The dip and the peak in the fluorescence transient of Chlorella pyrenoidosa. Biophys J 1969; 9:1-21. [PMID: 5782892 PMCID: PMC1367410 DOI: 10.1016/s0006-3495(69)86365-4] [Citation(s) in RCA: 158] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The fluorescence transient of Chlorella pyrenoidosa, excited by saturating light absorbed mainly by system II, has a dip D between the peak I at 75 msec and the large peak P at 400 msec (the times depend on light intensity). This dip is observed in aerobic cells and in anaerobic cells where it is prominent. In anaerobic cells, the I-D decline is hastened almost equally by absorption of either 705 or 650 nm background light. In anaerobic cells, supplementary 700 and 710 nm light given during the transient slightly hastens and heightens P. Methyl viologen, an exogenous system I electron acceptor, eliminates P. Results suggest that system I action causes D, and that P is due to reduction of Q (fluorescence quencher) and intersystem intermediates caused by development of a block in oxidation of XH (X being the primary electron acceptor of light reaction I). Mathematical analysis suggests that if only two forms of Q participate beyond I, then system I action is required for D. If three forms participate, then the system Q --> QH --> Q' (see text) may explain D. The Malkin model (14), in its present form, does not allow D.
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Munday JC. Light-induced changes in the fluorescence yield of chlorophyll A in vivo. IV. The effect of preillumination on the fluorescence transient of Chlorella pyrenoidosa. Biophys J 1969; 9:22-35. [PMID: 5782893 PMCID: PMC1367411 DOI: 10.1016/s0006-3495(69)86366-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The fluorescence transient of Chlorella pyrenoidosa, excited by saturating blue light, has a base level O, hump I, dip D, peak P, and at 1.5 sec a quasi-steady level S (12). With 2 sec exciting exposures and 4 min dark periods, preillumination-1 (lambda >/= 690 nm, intensities 1-750 ergs/sec-cm(2) incident), replacing the dark periods, lowers I more effectively than preillumination-2 (650 nm </= lambda </= 680 nm) in both aerobic and anaerobic cells. Results indicate that the intersystem electron transport pool A as well as the primary electron acceptor of pigment system II Q (fluorescence quencher) is normally being reduced at I. Preillumination-1 lowers and delays P. Preillumination-2 (absorbed by both pigment systems) also lowers P, but delays P only at low intensity; at high intensity it hastens P. Preillumination-1 raises S while preillumination-2 lowers S. With 30 instead of 2 sec exciting light exposures, preillumination-1 causes a large S increase, and at low intensity a P increase. The S effects seem to be of a long-term nature (26-29) rather than rapid changes in the redox state of Q. As exciting light intensity increases, fluorescence yield at P increases three-fold maximally. The ratio of P (anaerobic) to O (aerobic) is 5.5. These high ratios restrict the Franck-Rosenberg model of photosynthesis (13), which is based on fluorescence yield doubling.
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