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Nanotechnological interventions for treatment of trypanosomiasis in humans and animals. Drug Deliv Transl Res 2021; 10:945-961. [PMID: 32383004 DOI: 10.1007/s13346-020-00764-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Trypanosomiasis is a parasitic infection caused by Trypanosoma. It is one of the major causes of deaths in underprivileged, rural areas of Africa, America and Asia. Depending on the parasite species responsible for the disease, it can take two forms namely African trypanosomiasis (sleeping sickness) and American trypanosomiasis (Chagas disease). The complete life-cycle stages of trypanosomes span between insect vector (tsetse fly, triatomine bug) and mammalian host (humans, animals). Only few drugs have been approved for the treatment of trypanosomiasis. Moreover, current trypanocidal therapy has major limitations of poor efficacy, serious side effects and drug resistance. Due to the lack of economic gains from tropical parasitic infection, it has always been neglected by the researchers and drug manufacturers. There is an immense need of more effective innovative strategies to decrease the deaths associated with this diseases. Nanotechnological approaches for delivery of existing drugs have shown significant improvement in efficacy with many-fold decrease in their dose. The review emphasizes on nanotechnological interventions in the treatment of trypanosomiasis in both humans and animals. Current trypanocidal therapy and their limitations have also been discussed briefly. Graphical abstract.
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Performance of the SD BIOLINE® HAT rapid test in various diagnostic algorithms for gambiense human African trypanosomiasis in the Democratic Republic of the Congo. PLoS One 2017; 12:e0180555. [PMID: 28672036 PMCID: PMC5495481 DOI: 10.1371/journal.pone.0180555] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 06/16/2017] [Indexed: 01/22/2023] Open
Abstract
We carried out a study to compare the performance, in terms of sensitivity and specificity, of the new SD BIOLINE® HAT rapid diagnostic test (RDT) with the card agglutination test for trypanosomiasis (CATT) for diagnosis of human African trypanosomiasis (HAT) in the Democratic Republic of the Congo (DRC). Participants were enrolled actively by four mobile teams, and passively at four health facilities in three provinces. Consenting participants were tested concurrently with the RDT and CATT on whole blood. Those found positive by either test were tested with CATT on serial dilutions of plasma, and with a parasitological composite reference standard (CRS). Cases were only the individuals found positive by the CRS, while controls were negative by both CATT and RDT, as well as those that were positive by CATT or RDT, but were negative by the CRS, and had no history of HAT. Over five months, 131 cases and 13,527 controls were enrolled. The sensitivity of the RDT was 92.0% (95% confidence interval (CI) = 86.1-95.5), which was significantly higher than CATT (sensitivity 69.1%; 95% CI = 60.7-76.4). The sensitivity of CATT on plasma at a dilution of 1:8 was 59.0% (95% CI = 50.2-67.2). The specificity of the RDT was 97.1% (95% CIs = 96.8-97.4) while that of CATT was 98.0% (95% CIs = 97.8, 98.2) and specificities of algorithms involving CATT at 1:8 dilution were 99.6% (95% CI = 99.5-99.7). Reproducibility of results was excellent. We concluded that an algorithm in which the SD BIOLINE® HAT RDT is used for screening is optimal for case detection in both passive and active screening settings. However, the lower specificity of the RDT compared to that of CATT would result in a larger number of false positive individuals undergoing confirmatory testing.
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Miller MB, Patkar P, Singha UK, Chaudhuri M, David Nes W. 24-Methylenecyclopropane steroidal inhibitors: A Trojan horse in ergosterol biosynthesis that prevents growth of Trypanosoma brucei. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:305-313. [PMID: 27939999 DOI: 10.1016/j.bbalip.2016.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/23/2016] [Accepted: 12/05/2016] [Indexed: 01/09/2023]
Abstract
A new class of steroidal therapeutics based on phylogenetic-guided design of covalent inhibitors that target parasite-specific enzymes of ergosterol biosynthesis is shown to prevent growth of the protozoan-Trypanosoma brucei, responsible for sleeping sickness. In the presence of approximately 15±5μM 26,27-dehydrolanosterol, T. brucei procyclic or blood stream form growth is inhibited by 50%. This compound is actively converted by the parasite to an acceptable substrate of sterol C24-methyl transferase (SMT) that upon position-specific side chain methylation at C26 inactivates the enzyme. Treated cells show dose-dependent depletion of ergosterol and other 24β-methyl sterols with no accumulation of intermediates in contradistinction to profiles typical of tight binding inhibitor treatments to azoles showing loss of ergosterol accompanied by accumulation of toxic 14-methyl sterols. HEK cells accumulate 26,27-dehydrolanosterol without effect on cholesterol biosynthesis. During exposure of cloned TbSMT to 26,27-dehydrozymosterol, the enzyme is gradually inactivated (kcat/kinact=0.13min-1/0.08min-1; partition ratio of 1.6) while 26,27-dehydrolanosterol binds nonproductively. GC-MS analysis of the turnover product and bound intermediate released as a C26-methylated diol (C3-OH and C24-OH) confirmed substrate recognition and covalent binding to TbSMT. This study has potential implications for design of a novel class of chemotherapeutic leads functioning as mechanism-based inhibitors of ergosterol biosynthesis to treat neglected tropical diseases.
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Affiliation(s)
- Matthew B Miller
- Department of Chemistry and Biochemistry and Center for Chemical Biology, Texas Tech University, Lubbock, TX 79409, USA
| | - Presheet Patkar
- Department of Chemistry and Biochemistry and Center for Chemical Biology, Texas Tech University, Lubbock, TX 79409, USA
| | - Ujjal K Singha
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA
| | - Minu Chaudhuri
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN 37208, USA
| | - W David Nes
- Department of Chemistry and Biochemistry and Center for Chemical Biology, Texas Tech University, Lubbock, TX 79409, USA.
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Geiger A, Bossard G, Sereno D, Pissarra J, Lemesre JL, Vincendeau P, Holzmuller P. Escaping Deleterious Immune Response in Their Hosts: Lessons from Trypanosomatids. Front Immunol 2016; 7:212. [PMID: 27303406 PMCID: PMC4885876 DOI: 10.3389/fimmu.2016.00212] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/17/2016] [Indexed: 12/21/2022] Open
Abstract
The Trypanosomatidae family includes the genera Trypanosoma and Leishmania, protozoan parasites displaying complex digenetic life cycles requiring a vertebrate host and an insect vector. Trypanosoma brucei gambiense, Trypanosoma cruzi, and Leishmania spp. are important human pathogens causing human African trypanosomiasis (HAT or sleeping sickness), Chagas' disease, and various clinical forms of Leishmaniasis, respectively. They are transmitted to humans by tsetse flies, triatomine bugs, or sandflies, and affect millions of people worldwide. In humans, extracellular African trypanosomes (T. brucei) evade the hosts' immune defenses, allowing their transmission to the next host, via the tsetse vector. By contrast, T. cruzi and Leishmania sp. have developed a complex intracellular lifestyle, also preventing several mechanisms to circumvent the host's immune response. This review seeks to set out the immune evasion strategies developed by the different trypanosomatids resulting from parasite-host interactions and will focus on: clinical and epidemiological importance of diseases; life cycles: parasites-hosts-vectors; innate immunity: key steps for trypanosomatids in invading hosts; deregulation of antigen-presenting cells; disruption of efficient specific immunity; and the immune responses used for parasite proliferation.
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Affiliation(s)
- Anne Geiger
- UMR INTERTRYP, IRD-CIRAD, CIRAD TA A-17/G, Montpellier, France
| | | | - Denis Sereno
- UMR INTERTRYP, IRD-CIRAD, CIRAD TA A-17/G, Montpellier, France
| | - Joana Pissarra
- UMR INTERTRYP, IRD-CIRAD, CIRAD TA A-17/G, Montpellier, France
| | | | - Philippe Vincendeau
- UMR 177, IRD-CIRAD Université de Bordeaux Laboratoire de Parasitologie, Bordeaux, France
| | - Philippe Holzmuller
- UMRCMAEE CIRAD-INRA TA-A15/G “Contrôle des maladies animales exotiques et émergentes”, Montpellier, France
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Leaver DJ, Patkar P, Singha UK, Miller MB, Haubrich BA, Chaudhuri M, Nes WD. Fluorinated Sterols Are Suicide Inhibitors of Ergosterol Biosynthesis and Growth in Trypanosoma brucei. ACTA ACUST UNITED AC 2016; 22:1374-83. [PMID: 26496686 DOI: 10.1016/j.chembiol.2015.08.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/20/2015] [Accepted: 08/28/2015] [Indexed: 11/19/2022]
Abstract
Trypanosoma brucei, the causal agent for sleeping sickness, depends on ergosterol for growth. Here, we describe the effects of a mechanism-based inhibitor, 26-fluorolanosterol (26FL), which converts in vivo to a fluorinated substrate of the sterol C24-methyltransferase essential for sterol methylation and function of ergosterol, and missing from the human host. 26FL showed potent inhibition of ergosterol biosynthesis and growth of procyclic and bloodstream forms while having no effect on cholesterol biosynthesis or growth of human epithelial kidney cells. During exposure of cloned TbSMT to 26-fluorocholesta-5,7,24-trienol, the enzyme is gradually killed as a consequence of the covalent binding of the intermediate C25 cation to the active site (kcat/kinact = 0.26 min(-1)/0.24 min(-1); partition ratio of 1.08), whereas 26FL is non-productively bound. These results demonstrate that poisoning of ergosterol biosynthesis by a 26-fluorinated Δ(24)-sterol is a promising strategy for developing a new treatment for trypanosomiasis.
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Affiliation(s)
- David J Leaver
- Center for Chemical Biology and Department of Chemistry & Biochemistry, Texas Tech University, 2500 Broadway, Lubbock, TX 79409, USA; Institute of Chemistry and Biomedical Sciences, Nanjing University, 22 Hankou Road, Nanjing, Jiangsu, 210093, P.R. China
| | - Presheet Patkar
- Center for Chemical Biology and Department of Chemistry & Biochemistry, Texas Tech University, 2500 Broadway, Lubbock, TX 79409, USA
| | - Ujjal K Singha
- Department of Microbiology and Immunology, Meharry Medical College, 1005 Doctor D. B. Todd Jr. Boulevard, Nashville, TN 37208, USA
| | - Matthew B Miller
- Center for Chemical Biology and Department of Chemistry & Biochemistry, Texas Tech University, 2500 Broadway, Lubbock, TX 79409, USA
| | - Brad A Haubrich
- Center for Chemical Biology and Department of Chemistry & Biochemistry, Texas Tech University, 2500 Broadway, Lubbock, TX 79409, USA
| | - Minu Chaudhuri
- Department of Microbiology and Immunology, Meharry Medical College, 1005 Doctor D. B. Todd Jr. Boulevard, Nashville, TN 37208, USA
| | - W David Nes
- Center for Chemical Biology and Department of Chemistry & Biochemistry, Texas Tech University, 2500 Broadway, Lubbock, TX 79409, USA.
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Sun YN, No JH, Lee GY, Li W, Yang SY, Yang G, Schmidt TJ, Kang JS, Kim YH. Phenolic Constituents of Medicinal Plants with Activity against Trypanosoma brucei. Molecules 2016; 21:480. [PMID: 27077842 PMCID: PMC6273235 DOI: 10.3390/molecules21040480] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 04/01/2016] [Accepted: 04/01/2016] [Indexed: 11/24/2022] Open
Abstract
Neglected tropical diseases (NTDs) affect over one billion people all over the world. These diseases are classified as neglected because they impact populations in areas with poor financial conditions and hence do not attract sufficient research investment. Human African Trypanosomiasis (HAT or sleeping sickness), caused by the parasite Trypanosoma brucei, is one of the NTDs. The current therapeutic interventions for T. brucei infections often have toxic side effects or require hospitalization so that they are not available in the rural environments where HAT occurs. Furthermore, parasite resistance is increasing, so that there is an urgent need to identify novel lead compounds against this infection. Recognizing the wide structural diversity of natural products, we desired to explore and identify novel antitrypanosomal chemotypes from a collection of natural products obtained from plants. In this study, 440 pure compounds from various medicinal plants were tested against T. brucei by in a screening using whole cell in vitro assays. As the result, twenty-two phenolic compounds exhibited potent activity against cultures of T. brucei. Among them, eight compounds—4, 7, 11, 14, 15, 18, 20, and 21—showed inhibitory activity against T. brucei, with IC50 values below 5 µM, ranging from 0.52 to 4.70 μM. Based on these results, we attempt to establish some general trends with respect to structure-activity relationships, which indicate that further investigation and optimization of these derivatives might enable the preparation of potentially useful compounds for treating HAT.
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Affiliation(s)
- Ya Nan Sun
- College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea.
| | - Joo Hwan No
- Leishmania Research Laboratory, Institut Pasteur Korea, 696 Sampyeong-dong, Bundang-gu, Seongnam-si, Gyeonggi 463-400, Korea.
| | - Ga Young Lee
- College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea.
| | - Wei Li
- School of Biotechnology, Yeungnam University, Gyeongsan, Gyeongbuk 712-749, Korea.
| | - Seo Young Yang
- College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea.
| | - Gyongseon Yang
- Leishmania Research Laboratory, Institut Pasteur Korea, 696 Sampyeong-dong, Bundang-gu, Seongnam-si, Gyeonggi 463-400, Korea.
| | - Thomas J Schmidt
- Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of Münster, PharmaCampus, Corrensstrasse 48, D-48149 Münster, Germany.
| | - Jong Seong Kang
- College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea.
| | - Young Ho Kim
- College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea.
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Reimer LJ, Adams ER, Paine MJ, Ranson H, Coleman M, Thomsen EK, MacPherson EE, Hollingsworth TD, Kelly-Hope LA, Bockarie MJ, Ford L, Harrison RA, Stothard JR, Taylor MJ, Hamon N, Torr SJ. Fit for purpose: do we have the right tools to sustain NTD elimination? BMC Proc 2015; 9:S5. [PMID: 28281703 PMCID: PMC4699116 DOI: 10.1186/1753-6561-9-s10-s5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Priorities for NTD control programmes will shift over the next 10-20 years as the elimination phase reaches the ‘end game’ for some NTDs, and the recognition that the control of other NTDs is much more problematic. The current goal of scaling up programmes based on preventive chemotherapy (PCT) will alter to sustaining NTD prevention, through sensitive surveillance and rapid response to resurgence. A new suite of tools and approaches will be required for both PCT and Intensive Disease Management (IDM) diseases in this timeframe to enable disease endemic countries to: 1. Sensitively and sustainably survey NTD transmission and prevalence in order to identify and respond quickly to resurgence. 2. Set relevant control targets based not only on epidemiological indicators but also entomological and ecological metrics and use decision support technology to help meet those targets. 3. Implement verified and cost-effective tools to prevent transmission throughout the elimination phase. Liverpool School of Tropical Medicine (LSTM) and partners propose to evaluate and implement existing tools from other disease systems as well as new tools in the pipeline in order to support endemic country ownership in NTD decision-making during the elimination phase and beyond.
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Affiliation(s)
- Lisa J Reimer
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Emily R Adams
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Mark Ji Paine
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Hilary Ranson
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | | | | | | | | | | | - Louise Ford
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | | | - Mark J Taylor
- Liverpool School of Tropical Medicine, Liverpool, UK
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Tagoe DNA, Kalejaiye TD, de Koning HP. The ever unfolding story of cAMP signaling in trypanosomatids: vive la difference! Front Pharmacol 2015; 6:185. [PMID: 26441645 PMCID: PMC4561360 DOI: 10.3389/fphar.2015.00185] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/17/2015] [Indexed: 12/25/2022] Open
Abstract
Kinetoplastids are unicellular, eukaryotic, flagellated protozoans containing the eponymous kinetoplast. Within this order, the family of trypanosomatids are responsible for some of the most serious human diseases, including Chagas disease (Trypanosoma cruzi), sleeping sickness (Trypanosoma brucei spp.), and leishmaniasis (Leishmania spp). Although cAMP is produced during the life cycle stages of these parasites, its signaling pathways are very different from those of mammals. The absence of G-protein-coupled receptors, the presence of structurally different adenylyl cyclases, the paucity of known cAMP effector proteins and the stringent need for regulation of cAMP in the small kinetoplastid cells all suggest a significantly different biochemical pathway and likely cell biology. However, each of the main kinetoplastid parasites express four class 1-type cyclic nucleotide-specific phosphodiesterases (PDEA-D), which have highly similar catalytic domains to that of human PDEs. To date, only TbrPDEB, expressed as two slightly different isoforms TbrPDEB1 and B2, has been found to be essential when ablated. Although the genomes contain reasonably well conserved genes for catalytic and regulatory domains of protein kinase A, these have been shown to have varied structural and functional roles in the different species. Recent discovery of a role of cAMP/AMP metabolism in a quorum-sensing signaling pathway in T. brucei, and the identification of downstream cAMP Response Proteins (CARPs) whose expression levels correlate with sensitivity to PDE inhibitors, suggests a complex signaling cascade. The interplay between the roles of these novel CARPs and the quorum-sensing signaling pathway on cell division and differentiation makes for intriguing cell biology and a new paradigm in cAMP signal transduction, as well as potential targets for trypanosomatid-specific cAMP pathway-based therapeutics.
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Affiliation(s)
- Daniel N A Tagoe
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow , Glasgow, UK ; Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow , Glasgow, UK ; Department of Laboratory Technology, Division of Medical Laboratory Technology, University of Cape Coast , Cape Coast, Ghana
| | - Titilola D Kalejaiye
- Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow , Glasgow, UK
| | - Harry P de Koning
- Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow , Glasgow, UK
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Rahmani R, Ban K, Jones AJ, Ferrins L, Ganame D, Sykes ML, Avery VM, White KL, Ryan E, Kaiser M, Charman SA, Baell JB. 6-Arylpyrazine-2-carboxamides: A New Core for Trypanosoma brucei Inhibitors. J Med Chem 2015; 58:6753-65. [PMID: 26247439 DOI: 10.1021/acs.jmedchem.5b00438] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
From a whole-organism high throughput screen of approximately 87000 compounds against Trypanosoma brucei brucei, we recently identified eight new unique compounds for the treatment of human African trypanosomiasis. In an effort to understand the structure-activity relationships around these compounds, we report for the first time our results on a new class of trypanocides, the pyrazine carboxamides. Attracted by the low molecular weight (270 g·mol(-1)) of our starting hit (9) and its potency (0.49 μM), the SAR around the core was explored, leading to compounds having an EC50 as low as 25 nM against T. b. brucei and being more than 1500 times less toxic against mammalian L6 and HEK293 cell lines. The most potent compounds in the series were exquisitely selective for T. brucei over a panel of other protozoan parasites, showing an excellent correlation with the human infective parasite Trypanosoma brucei rhodesiense, the most potent compound (65) having an EC50 of 24 nM. The compounds are highly drug-like and are able to penetrate the CNS, their only limitation currently being their rate of microsomal metabolism. To that effect, efforts to identify potential metabolites of selected compounds are also reported.
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Affiliation(s)
- Raphaël Rahmani
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus) , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Kung Ban
- The Walter and Eliza Hall Institute , 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Amy J Jones
- Eskitis Institute for Drug Discovery, Griffith University , Brisbane Innovation Park, Don Young Road, Nathan, Queensland 4111, Australia
| | - Lori Ferrins
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus) , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Danny Ganame
- The Walter and Eliza Hall Institute , 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Melissa L Sykes
- Eskitis Institute for Drug Discovery, Griffith University , Brisbane Innovation Park, Don Young Road, Nathan, Queensland 4111, Australia
| | - Vicky M Avery
- Eskitis Institute for Drug Discovery, Griffith University , Brisbane Innovation Park, Don Young Road, Nathan, Queensland 4111, Australia
| | - Karen L White
- Centre for Drug Candidate Optimisation, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Eileen Ryan
- Centre for Drug Candidate Optimisation, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Marcel Kaiser
- University of Basel , Petersplatz 1, Basel, 4003, Switzerland.,Swiss Tropical and Public Health Institute , Socinstrasse 57, Basel, 4051, Switzerland
| | - Susan A Charman
- Centre for Drug Candidate Optimisation, Monash University , 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Jonathan B Baell
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus) , 381 Royal Parade, Parkville, Victoria 3052, Australia
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Nguyen S, Leija C, Kinch L, Regmi S, Li Q, Grishin NV, Phillips MA. Deoxyhypusine Modification of Eukaryotic Translation Initiation Factor 5A (eIF5A) Is Essential for Trypanosoma brucei Growth and for Expression of Polyprolyl-containing Proteins. J Biol Chem 2015; 290:19987-98. [PMID: 26082486 PMCID: PMC4528157 DOI: 10.1074/jbc.m115.656785] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 05/18/2015] [Indexed: 11/06/2022] Open
Abstract
The eukaryotic protozoan parasite Trypanosoma brucei is the causative agent of human African trypanosomiasis. Polyamine biosynthesis is essential in T. brucei, and the polyamine spermidine is required for synthesis of a novel cofactor called trypanothione and for deoxyhypusine modification of eukaryotic translation initiation factor 5A (eIF5A). eIF5A promotes translation of proteins containing polyprolyl tracts in mammals and yeast. To evaluate the function of eIF5A in T. brucei, we used RNA interference (RNAi) to knock down eIF5A levels and found that it is essential for T. brucei growth. The RNAi-induced growth defect was complemented by expression of wild-type human eIF5A but not by a Lys-50 mutant that blocks modification by deoxyhypusine. Bioinformatics analysis showed that 15% of the T. brucei proteome contains 3 or more consecutive prolines and that actin-related proteins and cysteine proteases were highly enriched in the group. Steady-state protein levels of representative proteins containing 9 consecutive prolines that are involved in actin assembly (formin and CAP/Srv2p) were significantly reduced by knockdown of eIF5A. Several T. brucei polyprolyl proteins are involved in flagellar assembly. Knockdown of TbeIF5A led to abnormal cell morphologies and detached flagella, suggesting that eIF5A is important for translation of proteins needed for these processes. Potential specialized functions for eIF5A in T. brucei in translation of variable surface glycoproteins were also uncovered. Inhibitors of deoxyhypusination would be expected to cause a pleomorphic effect on multiple cell processes, suggesting that deoxyhypusine/hypusine biosynthesis could be a promising drug target in not just T. brucei but in other eukaryotic pathogens.
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MESH Headings
- Amino Acid Sequence
- Animals
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Flagella/genetics
- Flagella/metabolism
- Flagella/ultrastructure
- Gene Knockdown Techniques
- Humans
- Lysine/analogs & derivatives
- Lysine/metabolism
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Molecular Sequence Data
- Peptide Initiation Factors/antagonists & inhibitors
- Peptide Initiation Factors/genetics
- Peptide Initiation Factors/metabolism
- Peptides/metabolism
- Protein Processing, Post-Translational
- Proteome/genetics
- Proteome/metabolism
- Protozoan Proteins/antagonists & inhibitors
- Protozoan Proteins/genetics
- Protozoan Proteins/metabolism
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Protozoan/antagonists & inhibitors
- RNA, Protozoan/genetics
- RNA, Protozoan/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- RNA-Binding Proteins/antagonists & inhibitors
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sequence Alignment
- Sequence Homology, Amino Acid
- Trypanosoma brucei brucei/genetics
- Trypanosoma brucei brucei/metabolism
- Trypanosoma brucei brucei/ultrastructure
- Eukaryotic Translation Initiation Factor 5A
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Affiliation(s)
| | | | | | | | - Qiong Li
- From the Departments of Pharmacology and
| | - Nick V Grishin
- Biophysics and Biochemistry and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041
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12
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Li Q, Leija C, Rijo-Ferreira F, Chen J, Cestari I, Stuart K, Tu BP, Phillips MA. GMP synthase is essential for viability and infectivity of Trypanosoma brucei despite a redundant purine salvage pathway. Mol Microbiol 2015; 97:1006-20. [PMID: 26043892 DOI: 10.1111/mmi.13083] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2015] [Indexed: 12/28/2022]
Abstract
The causative agent of human African trypanosomiasis, Trypanosoma brucei, lacks de novo purine biosynthesis and depends on purine salvage from the host. The purine salvage pathway is redundant and contains two routes to guanosine-5'-monophosphate (GMP) formation: conversion from xanthosine-5'-monophosphate (XMP) by GMP synthase (GMPS) or direct salvage of guanine by hypoxanthine-guanine phosphoribosyltransferase (HGPRT). We show recombinant T. brucei GMPS efficiently catalyzes GMP formation. Genetic knockout of GMPS in bloodstream parasites led to depletion of guanine nucleotide pools and was lethal. Growth of gmps null cells was only rescued by supraphysiological guanine concentrations (100 μM) or by expression of an extrachromosomal copy of GMPS. Hypoxanthine was a competitive inhibitor of guanine rescue, consistent with a common uptake/metabolic conversion mechanism. In mice, gmps null parasites were unable to establish an infection demonstrating that GMPS is essential for virulence and that plasma guanine is insufficient to support parasite purine requirements. These data validate GMPS as a potential therapeutic target for treatment of human African trypanosomiasis. The ability to strategically inhibit key metabolic enzymes in the purine pathway unexpectedly bypasses its functional redundancy by exploiting both the nature of pathway flux and the limited nutrient environment of the parasite's extracellular niche.
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Affiliation(s)
- Qiong Li
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Christopher Leija
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Filipa Rijo-Ferreira
- Department of Neuroscience, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA.,Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Jun Chen
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Igor Cestari
- Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109-5219, USA
| | - Kenneth Stuart
- Seattle Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109-5219, USA
| | - Benjamin P Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
| | - Margaret A Phillips
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, TX, 75390-9041, USA
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13
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Creek DJ, Mazet M, Achcar F, Anderson J, Kim DH, Kamour R, Morand P, Millerioux Y, Biran M, Kerkhoven EJ, Chokkathukalam A, Weidt SK, Burgess KEV, Breitling R, Watson DG, Bringaud F, Barrett MP. Probing the metabolic network in bloodstream-form Trypanosoma brucei using untargeted metabolomics with stable isotope labelled glucose. PLoS Pathog 2015; 11:e1004689. [PMID: 25775470 PMCID: PMC4361558 DOI: 10.1371/journal.ppat.1004689] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 01/19/2015] [Indexed: 01/21/2023] Open
Abstract
Metabolomics coupled with heavy-atom isotope-labelled glucose has been used to probe the metabolic pathways active in cultured bloodstream form trypomastigotes of Trypanosoma brucei, a parasite responsible for human African trypanosomiasis. Glucose enters many branches of metabolism beyond glycolysis, which has been widely held to be the sole route of glucose metabolism. Whilst pyruvate is the major end-product of glucose catabolism, its transamination product, alanine, is also produced in significant quantities. The oxidative branch of the pentose phosphate pathway is operative, although the non-oxidative branch is not. Ribose 5-phosphate generated through this pathway distributes widely into nucleotide synthesis and other branches of metabolism. Acetate, derived from glucose, is found associated with a range of acetylated amino acids and, to a lesser extent, fatty acids; while labelled glycerol is found in many glycerophospholipids. Glucose also enters inositol and several sugar nucleotides that serve as precursors to macromolecule biosynthesis. Although a Krebs cycle is not operative, malate, fumarate and succinate, primarily labelled in three carbons, were present, indicating an origin from phosphoenolpyruvate via oxaloacetate. Interestingly, the enzyme responsible for conversion of phosphoenolpyruvate to oxaloacetate, phosphoenolpyruvate carboxykinase, was shown to be essential to the bloodstream form trypanosomes, as demonstrated by the lethal phenotype induced by RNAi-mediated downregulation of its expression. In addition, glucose derivatives enter pyrimidine biosynthesis via oxaloacetate as a precursor to aspartate and orotate. In this work we have followed the distribution of carbon derived from glucose in bloodstream form trypanosomes, the causative agent of African trypanosomiasis, revealing it to enter a diverse range of metabolites. The work involved using 13C-labelled glucose and following the fate of the labelled carbon with an LC-MS based metabolomics platform. Beyond glycolysis and the oxidative branch of the pentose phosphate pathway the label entered lipid biosynthesis both through glycerol 3-phosphate and also acetate. Glucose derived carbon also entered nucleotide synthesis through ribose and pyrimidine synthesis through oxaloacetate-derived aspartate. Appreciable quantities of the carboxylic acids succinate and malate were identified, although labelling patterns indicate they are not TCA cycle derived. Amino sugars and sugar nucleotides were also labelled as was inositol used in protein modification but not in inositol phospholipid headgroup production. We confirm active and essential oxaloacetate production in bloodstream form trypanosomes and show that phosphoenolpyruvate carboxykinase is essential to these parasites using RNA interference. The amount of glucose entering these metabolites is minor compared to the quantity that enters pyruvate excreted from the cell, but the observation that enzymes contributing to the metabolism of glucose beyond glycolysis can be essential offers potential new targets for chemotherapy against trypanosomiasis.
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Affiliation(s)
- Darren J. Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville Campus, Parkville, Victoria, Australia
| | - Muriel Mazet
- Centre de Résonance Magnétique des Systèmes Biologiques, Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Fiona Achcar
- Wellcome Trust Centre of Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jana Anderson
- Department of Public Health, Institute of Health and Wellbeing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Dong-Hyun Kim
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Ruwida Kamour
- Department of Medicinal and Pharmaceutical Chemistry, Faculty of Pharmacy, University of Tripoli, Tripoli, Libya
| | - Pauline Morand
- Centre de Résonance Magnétique des Systèmes Biologiques, Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Yoann Millerioux
- Centre de Résonance Magnétique des Systèmes Biologiques, Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Marc Biran
- Centre de Résonance Magnétique des Systèmes Biologiques, Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Eduard J. Kerkhoven
- Systems and Synthetic Biology, Department of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden
| | - Achuthanunni Chokkathukalam
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, Garscube Campus, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Stefan K. Weidt
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, Garscube Campus, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Karl E. V. Burgess
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, Garscube Campus, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Rainer Breitling
- Manchester Institute of Biotechnology, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - David G. Watson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Frédéric Bringaud
- Centre de Résonance Magnétique des Systèmes Biologiques, Université de Bordeaux, CNRS UMR-5536, Bordeaux, France
| | - Michael P. Barrett
- Wellcome Trust Centre of Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, Garscube Campus, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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14
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Norman FF, Monge-Maillo B, Martínez-Pérez Á, Perez-Molina JA, López-Vélez R. Parasitic infections in travelers and immigrants: part I protozoa. Future Microbiol 2015; 10:69-86. [DOI: 10.2217/fmb.14.105] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
ABSTRACT The growth in international commerce, travel and migration contribute to the global emergence of certain parasitic infections. Importation of vectors and food products may contribute to the emergence of protozoan infections in nonendemic countries. Infections such as malaria are potentially fatal, especially in nonimmune patients, and outcome depends largely on timely diagnosis and treatment. Diagnosis/management of imported parasitic infections may be complex especially as some patients may have underlying immunosuppressive conditions such as HIV infection. Major challenges concern the development of improved diagnostic techniques, safer/more effective drug therapies and identification of biological markers of progression and response to treatment. Imported parasitic diseases which may be transmitted vertically or through blood transfusion/organ donation could become a public health priority in the near future. Climate change may affect arthropod distribution and facilitate the spread of protozoan vector-borne diseases. The first part of this review focuses on protozoan infections in travelers and immigrants.
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Affiliation(s)
- Francesca F Norman
- Tropical Medicine & Clinical Parasitology, Infectious Diseases Department, Ramon y Cajal Hospital, Ctra. De Colmenar, Km 9.1, 28034 Madrid, Spain
| | - Begoña Monge-Maillo
- Tropical Medicine & Clinical Parasitology, Infectious Diseases Department, Ramon y Cajal Hospital, Ctra. De Colmenar, Km 9.1, 28034 Madrid, Spain
| | - Ángela Martínez-Pérez
- Tropical Medicine & Clinical Parasitology, Infectious Diseases Department, Ramon y Cajal Hospital, Ctra. De Colmenar, Km 9.1, 28034 Madrid, Spain
| | - Jose A Perez-Molina
- Tropical Medicine & Clinical Parasitology, Infectious Diseases Department, Ramon y Cajal Hospital, Ctra. De Colmenar, Km 9.1, 28034 Madrid, Spain
| | - Rogelio López-Vélez
- Tropical Medicine & Clinical Parasitology, Infectious Diseases Department, Ramon y Cajal Hospital, Ctra. De Colmenar, Km 9.1, 28034 Madrid, Spain
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15
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Manos-Turvey A, Watson EE, Sykes ML, Jones AJ, Baell JB, Kaiser M, Avery VM, Payne RJ. Synthesis and evaluation of phenoxymethylbenzamide analogues as anti-trypanosomal agents. MEDCHEMCOMM 2015. [DOI: 10.1039/c4md00406j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of a compound library based on a high throughput screening hit led to the discovery of several potent anti-trypanosomal agents.
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Affiliation(s)
| | - Emma E. Watson
- School of Chemistry
- The University of Sydney
- Sydney
- Australia
| | - Melissa L. Sykes
- Discovery Biology
- Eskitis Institute for Drug Discovery
- Griffith University
- Australia
| | - Amy J. Jones
- Discovery Biology
- Eskitis Institute for Drug Discovery
- Griffith University
- Australia
| | - Jonathan B. Baell
- Department of Medicinal Chemistry
- Faculty of Pharmacy and Pharmaceutical Sciences
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Australia
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute
- Basel
- Switzerland
- University of Basel
- Basel
| | - Vicky M. Avery
- Discovery Biology
- Eskitis Institute for Drug Discovery
- Griffith University
- Australia
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16
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Ong HB, Lee WS, Patterson S, Wyllie S, Fairlamb AH. Homoserine and quorum-sensing acyl homoserine lactones as alternative sources of threonine: a potential role for homoserine kinase in insect-stage Trypanosoma brucei. Mol Microbiol 2014; 95:143-56. [PMID: 25367138 PMCID: PMC4460637 DOI: 10.1111/mmi.12853] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2014] [Indexed: 12/29/2022]
Abstract
De novo synthesis of threonine from aspartate occurs via the β-aspartyl phosphate pathway in plants, bacteria and fungi. However, the Trypanosoma brucei genome encodes only the last two steps in this pathway: homoserine kinase (HSK) and threonine synthase. Here, we investigated the possible roles for this incomplete pathway through biochemical, genetic and nutritional studies. Purified recombinant TbHSK specifically phosphorylates L-homoserine and displays kinetic properties similar to other HSKs. HSK null mutants generated in bloodstream forms displayed no growth phenotype in vitro or loss of virulence in vivo. However, following transformation into procyclic forms, homoserine, homoserine lactone and certain acyl homoserine lactones (AHLs) were found to substitute for threonine in growth media for wild-type procyclics, but not HSK null mutants. The tsetse fly is considered to be an unlikely source of these nutrients as it feeds exclusively on mammalian blood. Bioinformatic studies predict that tsetse endosymbionts possess part (up to homoserine in Wigglesworthia glossinidia) or all of the β-aspartyl phosphate pathway (Sodalis glossinidius). In addition S. glossinidius is known to produce 3-oxohexanoylhomoserine lactone which also supports trypanosome growth. We propose that T. brucei has retained HSK and threonine synthase in order to salvage these nutrients when threonine availability is limiting.
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Affiliation(s)
- Han B Ong
- Division of Biological Chemistry & Drug Discovery, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
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17
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Shameer S, Logan-Klumpler FJ, Vinson F, Cottret L, Merlet B, Achcar F, Boshart M, Berriman M, Breitling R, Bringaud F, Bütikofer P, Cattanach AM, Bannerman-Chukualim B, Creek DJ, Crouch K, de Koning HP, Denise H, Ebikeme C, Fairlamb AH, Ferguson MAJ, Ginger ML, Hertz-Fowler C, Kerkhoven EJ, Mäser P, Michels PAM, Nayak A, Nes DW, Nolan DP, Olsen C, Silva-Franco F, Smith TK, Taylor MC, Tielens AGM, Urbaniak MD, van Hellemond JJ, Vincent IM, Wilkinson SR, Wyllie S, Opperdoes FR, Barrett MP, Jourdan F. TrypanoCyc: a community-led biochemical pathways database for Trypanosoma brucei. Nucleic Acids Res 2014; 43:D637-44. [PMID: 25300491 PMCID: PMC4384016 DOI: 10.1093/nar/gku944] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The metabolic network of a cell represents the catabolic and anabolic reactions that interconvert small molecules (metabolites) through the activity of enzymes, transporters and non-catalyzed chemical reactions. Our understanding of individual metabolic networks is increasing as we learn more about the enzymes that are active in particular cells under particular conditions and as technologies advance to allow detailed measurements of the cellular metabolome. Metabolic network databases are of increasing importance in allowing us to contextualise data sets emerging from transcriptomic, proteomic and metabolomic experiments. Here we present a dynamic database, TrypanoCyc (http://www.metexplore.fr/trypanocyc/), which describes the generic and condition-specific metabolic network of Trypanosoma brucei, a parasitic protozoan responsible for human and animal African trypanosomiasis. In addition to enabling navigation through the BioCyc-based TrypanoCyc interface, we have also implemented a network-based representation of the information through MetExplore, yielding a novel environment in which to visualise the metabolism of this important parasite.
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Affiliation(s)
- Sanu Shameer
- Institut National de la Recherche Agronomique (INRA), UMR1331, TOXALIM (Research Centre in Food Toxicology), Université de Toulouse, Toulouse, France
| | | | - Florence Vinson
- Institut National de la Recherche Agronomique (INRA), UMR1331, TOXALIM (Research Centre in Food Toxicology), Université de Toulouse, Toulouse, France
| | - Ludovic Cottret
- Institut National de la Recherche Agronomique (INRA), UMR441, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Auzeville, France
| | - Benjamin Merlet
- Institut National de la Recherche Agronomique (INRA), UMR1331, TOXALIM (Research Centre in Food Toxicology), Université de Toulouse, Toulouse, France
| | - Fiona Achcar
- University of Glasgow, Glasgow, Scotland, G12 8QQ, UK
| | - Michael Boshart
- Ludwig-Maximilians-Universität München, Biocenter, 82152-Martinsried, Germany
| | - Matthew Berriman
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Rainer Breitling
- Manchester Institute of Biotechnology, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | | | | | | | | | - Darren J Creek
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia
| | | | | | - Hubert Denise
- European Bioinformatics Institute (EMBL-EBI), Hinxton, Cambridge, CB10 1SD, UK
| | | | | | | | - Michael L Ginger
- Divisionof Biomedical and Life Sciences, Lancaster University, Bailrigg, Lancaster, LA1 4YG, UK
| | | | - Eduard J Kerkhoven
- Chalmers University of Technology, Kemivägen 10, 412 96, Göteborg, Sweden
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Socinstr. 57, Basel 4051, Switzerland
| | | | - Archana Nayak
- University of Glasgow, Glasgow, Scotland, G12 8QQ, UK
| | | | | | | | | | - Terry K Smith
- University of St Andrews, St Andrews, Scotland, KY16 9ST, UK
| | | | - Aloysius G M Tielens
- Utrecht University, Utrecht, 3508 TD, The Netherlands Erasmus University Medical Center, Rotterdam, 3015 CE, The Netherlands
| | - Michael D Urbaniak
- Divisionof Biomedical and Life Sciences, Lancaster University, Bailrigg, Lancaster, LA1 4YG, UK
| | | | | | | | - Susan Wyllie
- University of Dundee, Dundee, Scotland, DD1 4HN, UK
| | | | | | - Fabien Jourdan
- Institut National de la Recherche Agronomique (INRA), UMR1331, TOXALIM (Research Centre in Food Toxicology), Université de Toulouse, Toulouse, France
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18
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Woodring JL, Pollastri MP. Inhibitors of Protozoan Phosphodiesterases as Potential Therapeutic Approaches for Tropical Diseases. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/9783527682348.ch12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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19
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Ferrins L, Gazdik M, Rahmani R, Varghese S, Sykes ML, Jones AJ, Avery VM, White KL, Ryan E, Charman SA, Kaiser M, Bergström CAS, Baell JB. Pyridyl Benzamides as a Novel Class of Potent Inhibitors for the Kinetoplastid Trypanosoma brucei. J Med Chem 2014; 57:6393-402. [DOI: 10.1021/jm500191u] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
| | - Michelle Gazdik
- Department
of Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
- The Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | | | - Swapna Varghese
- Department
of Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Melissa L. Sykes
- Eskitis
Institute
for Drug Discovery, Griffith University, Brisbane Innovation Park, Don Young
Road, Nathan, Queensland 4111, Australia
| | - Amy J. Jones
- Eskitis
Institute
for Drug Discovery, Griffith University, Brisbane Innovation Park, Don Young
Road, Nathan, Queensland 4111, Australia
| | - Vicky M. Avery
- Eskitis
Institute
for Drug Discovery, Griffith University, Brisbane Innovation Park, Don Young
Road, Nathan, Queensland 4111, Australia
| | | | | | | | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel, 4051, Switzerland
- University of Basel, Petersplatz
1, Basel, 4003, Switzerland
| | - Christel A. S. Bergström
- Department
of Pharmacy, Uppsala University, Biomedical Center P.O. Box 580, SE-751
23 Uppsala, Sweden
| | - Jonathan B. Baell
- The Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, Victoria 3052, Australia
- Department
of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
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20
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Drug discovery and human African trypanosomiasis: a disease less neglected? Future Med Chem 2014; 5:1801-41. [PMID: 24144414 DOI: 10.4155/fmc.13.162] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Human African trypanosomiasis (HAT) has been neglected for a long time. The most recent drug to treat this disease, eflornithine, was approved by the US FDA in 2000. Current treatments exhibit numerous problematic side effects and are often ineffective against the debilitating CNS resident stage of the disease. Fortunately, several partnerships and initiatives have been formed over the last 20 years in an effort to eradicate HAT, along with a number of other neglected diseases. This has led to an increasing number of foundations and research institutions that are currently working on the development of new drugs for HAT and tools with which to diagnose and treat patients. New biochemical pathways as therapeutic targets are emerging, accompanied by increasing numbers of new antitrypanosomal compound classes. The future looks promising that this collaborative approach will facilitate eagerly awaited breakthroughs in the treatment of HAT.
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21
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Rashad AA, Jones AJ, Avery VM, Baell J, Keller PA. Facile Synthesis and Preliminary Structure-Activity Analysis of New Sulfonamides Against Trypanosoma brucei. ACS Med Chem Lett 2014; 5:496-500. [PMID: 24900868 DOI: 10.1021/ml400487t] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 03/10/2014] [Indexed: 12/17/2022] Open
Abstract
The high throughput screening of a library of over 87,000 drug-like compounds against the African sleeping sickness parasite resulted in the discovery of hits with a wide range of molecular diversity. We report here the medicinal chemistry development of one such hit, a tetrahydroisoquinoline disulfonamide, with the synthesis and testing of 26 derivatives against the trypanosome subspecies. Activities in the 2-4 μM range were revealed with a selectivity index suitable for further development.
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Affiliation(s)
- Adel A. Rashad
- School
of Chemistry, University of Wollongong, Wollongong 2522, Australia
| | - Amy J. Jones
- Eskitis
Institute for Drug Discovery, Griffith University, Brisbane Innovation Park, Don Young
Road, Nathan 4111, Australia
| | - Vicky M. Avery
- Eskitis
Institute for Drug Discovery, Griffith University, Brisbane Innovation Park, Don Young
Road, Nathan 4111, Australia
| | - Jonathan Baell
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Australia
| | - Paul A. Keller
- School
of Chemistry, University of Wollongong, Wollongong 2522, Australia
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22
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Genetic validation of Trypanosoma brucei glutathione synthetase as an essential enzyme. EUKARYOTIC CELL 2014; 13:614-24. [PMID: 24610661 DOI: 10.1128/ec.00015-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human African trypanosomiasis (HAT) is a debilitating and fatal vector-borne disease. Polyamine biosynthesis is the target of one of the key drugs (eflornithine) used for the treatment of late-stage disease, suggesting that the pathway might be exploited for the identification of additional drug targets. The polyamine spermidine is required in trypanosomatid parasites for formation of a unique redox cofactor termed trypanothione, which is formed from the conjugation of glutathione to spermidine. Here we characterize recombinant Trypanosoma brucei glutathione synthetase (TbGS) and show that depletion of TbGS in blood-form parasites using a regulated knockout strategy leads to loss of trypanothione and to cell death as quantified by fluorescence-activated cell sorter (FACS) analysis. These data suggest that >97% depletion of TbGS is required before trypanothione is depleted and cell growth arrest is observed. Exogenous glutathione was able to partially compensate for the loss of TbGS, suggesting that parasites are able to transport intact glutathione. Finally, reduced expression of TbGS leads to increased levels of upstream glutathione biosynthetic enzymes and decreased expression of polyamine biosynthetic enzymes, providing evidence that the cells cross regulate the two branches of the trypanothione biosynthetic pathway to maintain spermidine and trypanothione homeostasis.
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23
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Babokhov P, Sanyaolu AO, Oyibo WA, Fagbenro-Beyioku AF, Iriemenam NC. A current analysis of chemotherapy strategies for the treatment of human African trypanosomiasis. Pathog Glob Health 2014; 107:242-52. [PMID: 23916333 DOI: 10.1179/2047773213y.0000000105] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Despite the recent advances in drug research, finding a safe, effective, and easy to use chemotherapy for human African trypanosomiasis (HAT) remains a challenging task. The four current anti-trypanosomiasis drugs have major disadvantages that limit more widespread use of these drugs in the endemic regions of sub-Saharan Africa. Pentamidine and suramin are limited by their effectiveness against the only first stage of Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, respectively. In addition, melarsoprol and eflornithine (two second stage drugs) each have disadvantages of their own. The former is toxic and has increasing treatment failures while the latter is expensive, laborious to administer, and lacks efficacy against T. b. rhodesiense. Furthermore, melarsoprol's toxicity and decreasing efficacy are glaring problems and phasing out the drug as a frontline treatment against T. b. gambiense is now possible with the emergence of competent, safe combination chemotherapies such as nifurtimox-eflornithine combination treatment (NECT). The future of eflornithine, on the other hand, is more promising. The drug is useful in the context of combination chemotherapy and potential orally administered analogues. Due to the limits of monotherapies, greater emphasis should be placed on the research and development of combination chemotherapies, based on the successful clinical tests with NECT and its current use as a frontline anti-trypanosomiasis treatment. This review discussed the current and future chemotherapy strategies for the treatment of HAT.
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24
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Holzmuller P, Grébaut P, Semballa S, Gonzatti MI, Geiger A. Proteomics: a new way to improve human African trypanosomiasis diagnosis? Expert Rev Proteomics 2014; 10:289-301. [DOI: 10.1586/epr.13.14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Abstract
Rhizobiales (formerly named Rickettsiales) cause in rare instances meningitis and meningovasculitis, respectively. In case of history of exposure, infection by Rhizobiales needs to be considered since both diagnosis and therapy may be extremely difficult and pathogen-specific. The same applies to protozoa; in this chapter, Babesia species, free-living amoebae and Entamoeba histolytica infection, including severe meningitis and brain abscess, infection by Trypanosoma species (South American and African trypanosomiasis) are discussed with respect to history, epidemiology, clinical signs, and symptoms as well as differential diagnosis and therapy. Parasitic flatworms and roundworms, potentially able to invade the central nervous system, trematodes (flukes), cestodes (in particular, Cysticercus cellulosae), but also nematodes (in particular, Strongyloides spp. in the immunocompromised) are of worldwide importance. In contrast, filarial worms, Toxocara spp., Trichinella spp., Gnathostoma and Angiostrongylus spp. are seen only in certain geographically confined areas. Even more regionally confined are infestations of the central nervous system by metazoa, in particular, tongue worms (=arthropods) or larvae of flies (=maggots). The aim of this chapter is (1) to alert the neurologist to these infections, and (2) to enable the attending emergency neurologist to take a knowledgeable history, with an emphasis on epidemiology, clinical signs, and symptoms as well as therapeutic management possibilities.
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Affiliation(s)
- Erich Schmutzhard
- Department of Neurology, Medical University Hospital Innsbruck, Innsbruck, Austria.
| | - Raimund Helbok
- Department of Neurology, Medical University Hospital Innsbruck, Innsbruck, Austria
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Leong S, Simo G, Camara M, Jamonneau V, Kabore J, Ilboudo H, Bucheton B, Hoheisel JD, Clayton C. The miRNA and mRNA Signatures of Peripheral Blood Cells in Humans Infected with Trypanosoma brucei gambiense. PLoS One 2013; 8:e67312. [PMID: 23826264 PMCID: PMC3695006 DOI: 10.1371/journal.pone.0067312] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 05/15/2013] [Indexed: 01/08/2023] Open
Abstract
Simple, reliable tools for diagnosis of human African Trypanosomiases could ease field surveillance and enhance patient care. In particular, current methods to distinguish patients with (stage II) and without (stage I) brain involvement require samples of cerebrospinal fluid. We describe here an exploratory study to find out whether miRNAs from peripheral blood leukocytes might be useful in diagnosis of human trypanosomiasis, or for determining the stage of the disease. Using microarrays, we measured miRNAs in samples from Trypanosoma brucei gambiense-infected patients (9 stage I, 10 stage II), 8 seronegative parasite-negative controls and 12 seropositive, but parasite-negative subjects. 8 miRNAs (out of 1205 tested) showed significantly lower expression in patients than in seronegative, parasite-negative controls, and 1 showed increased expression. There were no clear differences in miRNAs between patients in different disease stages. The miRNA profiles could not distinguish seropositive, but parasitologically negative samples from controls and results within this group did not correlate with those from the trypanolysis test. Some of the regulated miRNAs, or their predicted mRNA targets, were previously reported changed during other infectious diseases or cancer. We conclude that the changes in miRNA profiles of peripheral blood lymphocytes in human African trypanosomiasis are related to immune activation or inflammation, are probably disease-non-specific, and cannot be used to determine the disease stage. The approach has little promise for diagnostics but might yield information about disease pathology.
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Affiliation(s)
- Smiths Leong
- Division of Functional Genome Analysis, Deutsche Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Gustave Simo
- Department of Biochemistry, University of Dschang, Dschang, West Cameroon
| | - Mamadou Camara
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine en Guinée, Conakry, Guinée
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Vincent Jamonneau
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
- Institut de Recherche pour le Développement, Unité mixte de recherche 177 (UMR-177), Campus International de Baillarguet, Montpellier, France
| | - Jacques Kabore
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Hamidou Ilboudo
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Bruno Bucheton
- Centre international de recherche-développement sur l’elevage en zone subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
- Institut de Recherche pour le Développement, Unité mixte de recherche 177 (UMR-177), Campus International de Baillarguet, Montpellier, France
| | - Jörg D. Hoheisel
- Division of Functional Genome Analysis, Deutsche Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
- * E-mail:
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Xiao Y, Nguyen S, Kim SH, Volkov OA, Tu BP, Phillips MA. Product feedback regulation implicated in translational control of the Trypanosoma brucei S-adenosylmethionine decarboxylase regulatory subunit prozyme. Mol Microbiol 2013; 88:846-61. [PMID: 23634831 DOI: 10.1111/mmi.12226] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2013] [Indexed: 12/12/2022]
Abstract
Human African sleeping sickness (HAT) is caused by the parasitic protozoan Trypanosoma brucei. Polyamine biosynthesis is an important drug target in the treatment of HAT. Previously we showed that trypanosomatid S-adenosylmethionine decarboxylase (AdoMetDC), a key enzyme for biosynthesis of the polyamine spermidine, is activated by heterodimer formation with an inactive paralogue termed prozyme. Furthermore, prozyme protein levels were regulated in response to reduced AdoMetDC activity. Herein we show that T. brucei encodes three prozyme transcripts. The 3'UTRs of these transcripts were mapped and chloramphenicol acetyltransferase (CAT) reporter constructs were used to identify a 1.2 kb region that contained a 3'UTR prozyme regulatory element sufficient to upregulate CAT protein levels (but not RNA) upon AdoMetDC inhibition, supporting the hypothesis that prozyme expression is regulated translationally. To gain insight into trans-acting factors, genetic rescue of AdoMetDC RNAi knock-down lines with human AdoMetDC was performed leading to rescue of the cell growth block, and restoration of prozyme protein to wild-type levels. Metabolite analysis showed that prozyme protein levels were inversely proportional to intracellular levels of decarboxylated AdoMet (dcAdoMet). These data suggest that prozyme translation may be regulated by dcAdoMet, a metabolite not previously identified to play a regulatory role.
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Affiliation(s)
- Yanjing Xiao
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9041, USA
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28
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Sanchez LM, Knudsen GM, Hartmann C, De Muylder G, Mascuch SM, Mackey ZB, Gerwick L, Clayton C, McKerrow JH, Linington RG. Examination of the mode of action of the almiramide family of natural products against the kinetoplastid parasite Trypanosoma brucei. JOURNAL OF NATURAL PRODUCTS 2013; 76:630-41. [PMID: 23445522 PMCID: PMC3971013 DOI: 10.1021/np300834q] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Almiramide C is a marine natural product with low micromolar activity against Leishmania donovani, the causative agent of leishmaniasis. We have now shown that almiramide C is also active against the related parasite Trypanosoma brucei, the causative agent of human African trypanosomiasis. A series of activity-based probes have been synthesized to explore both the molecular target of this compound series in T. brucei lysates and site localization through epifluorescence microscopy. These target identification studies indicate that the almiramides likely perturb glycosomal function through disruption of membrane assembly machinery. Glycosomes, which are organelles specific to kinetoplastid parasites, house the first seven steps of glycolysis and have been shown to be essential for parasite survival in the bloodstream stage. There are currently no reported small-molecule disruptors of glycosome function, making the almiramides unique molecular probes for this understudied parasite-specific organelle. Additionally, examination of toxicity in an in vivo zebrafish model has shown that these compounds have little effect on organism development, even at high concentrations, and has uncovered a potential side effect through localization of fluorescent derivatives to zebrafish neuromast cells. Combined, these results further our understanding of the potential value of this lead series as development candidates against T. brucei.
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Affiliation(s)
- Laura M. Sanchez
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064
| | - Giselle M. Knudsen
- Sandler Center for Drug Discovery, University of California San Francisco, San Francisco, CA 94143
| | - Claudia Hartmann
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Heidelberg, Heidelberg, Germany D-69120
| | - Geraldine De Muylder
- Sandler Center for Drug Discovery, University of California San Francisco, San Francisco, CA 94143
| | - Samantha M. Mascuch
- Center for Marine Biotechnology and Biomedicine, Scripps Institute of Oceanography, University of California San Diego, San Diego, CA 92093
| | - Zachary B. Mackey
- Sandler Center for Drug Discovery, University of California San Francisco, San Francisco, CA 94143
| | - Lena Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institute of Oceanography, University of California San Diego, San Diego, CA 92093
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Heidelberg, Heidelberg, Germany D-69120
| | - James H. McKerrow
- Sandler Center for Drug Discovery, University of California San Francisco, San Francisco, CA 94143
| | - Roger G. Linington
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064
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Cestari I, Stuart K. Inhibition of isoleucyl-tRNA synthetase as a potential treatment for human African Trypanosomiasis. J Biol Chem 2013; 288:14256-14263. [PMID: 23548908 DOI: 10.1074/jbc.m112.447441] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Trypanosoma brucei sp. causes human African trypanosomiasis (HAT; African sleeping sickness). The parasites initially proliferate in the hemolymphatic system and then invade the central nervous system, which is lethal if not treated. New drugs are needed for HAT because the approved drugs are few, toxic, and difficult to administer, and drug resistance is spreading. We showed by RNAi knockdown that T. brucei isoleucyl-tRNA synthetase is essential for the parasites in vitro and in vivo in a mouse model of infection. By structure prediction and experimental analysis, we also identified small molecules that inhibit recombinant isoleucyl-tRNA synthetase and that are lethal to the parasites in vitro and highly selective compared with mammalian cells. One of these molecules acts as a competitive inhibitor of the enzyme and cures mice of the infection. Because members of this class of molecules are known to cross the blood-brain barrier in humans and to be tolerated, they may be attractive as leading candidates for drug development for HAT.
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Affiliation(s)
- Igor Cestari
- Seattle Biomedical Research Institute, Seattle, Washington 98109
| | - Kenneth Stuart
- Seattle Biomedical Research Institute, Seattle, Washington 98109; Department of Global Health, University of Washington, Seattle, Washington 98195.
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30
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Kennedy PG. Clinical features, diagnosis, and treatment of human African trypanosomiasis (sleeping sickness). Lancet Neurol 2012; 12:186-94. [PMID: 23260189 DOI: 10.1016/s1474-4422(12)70296-x] [Citation(s) in RCA: 276] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Human African trypanosomiasis, or sleeping sickness, is caused by infection with parasites of the genus Trypanosoma, transmitted by the tsetse fly. The disease has two forms, Trypanosoma brucei (T b) rhodesiense and T b gambiense; and is almost always fatal if untreated. Despite a recent reduction in the number of reported cases, patients with African trypanosomiasis continue to present major challenges to clinicians. Because treatment for CNS-stage disease can be very toxic, diagnostic staging to distinguish early-stage from late-stage disease when the CNS in invaded is crucial but remains problematic. Melarsoprol is the only available treatment for late-stage T b rhodesiense infection, but can be lethal to 5% of patients owing to post-treatment reactive encephalopathy. Eflornithine combined with nifurtimox is the first-line treatment for late-stage T b gambiense. New drugs are in the pipeline for treatment of CNS human African trypanosomiasis, giving rise to cautious optimism.
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Affiliation(s)
- Peter Ge Kennedy
- Department of Neurology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK.
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31
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Fexinidazole: a potential new drug candidate for Chagas disease. PLoS Negl Trop Dis 2012; 6:e1870. [PMID: 23133682 PMCID: PMC3486905 DOI: 10.1371/journal.pntd.0001870] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 09/05/2012] [Indexed: 12/02/2022] Open
Abstract
Background New safe and effective treatments for Chagas disease (CD) are urgently needed. Current chemotherapy options for CD have significant limitations, including failure to uniformly achieve parasitological cure or prevent the chronic phase of CD, and safety and tolerability concerns. Fexinidazole, a 2-subsituted 5-nitroimidazole drug candidate rediscovered following extensive compound mining by the Drugs for Neglected Diseases initiative and currently in Phase I clinical study for the treatment of human African trypanosomiasis, was evaluated in experimental models of acute and chronic CD caused by different strains of Trypanosoma cruzi. Methods and Findings We investigated the in vivo activity of fexinidazole against T. cruzi, using mice as hosts. The T. cruzi strains used in the study were previously characterized in murine models as susceptible (CL strain), partially resistant (Y strain), and resistant (Colombian and VL-10 strains) to the drugs currently in clinical use, benznidazole and nifurtimox. Our results demonstrated that fexinidazole was effective in suppressing parasitemia and preventing death in infected animals for all strains tested. In addition, assessment of definitive parasite clearance (cure) through parasitological, PCR, and serological methods showed cure rates of 80.0% against CL and Y strains, 88.9% against VL-10 strain, and 77.8% against Colombian strain among animals treated during acute phase, and 70% (VL-10 strain) in those treated in chronic phase. Benznidazole had a similar effect against susceptible and partially resistant T. cruzi strains. Fexinidazole treatment was also shown to reduce myocarditis in all animals infected with VL-10 or Colombian resistant T. cruzi strains, although parasite eradication was not achieved in all treated animals at the tested doses. Conclusions Fexinidazole is an effective oral treatment of acute and chronic experimental CD caused by benznidazole-susceptible, partially resistant, and resistant T. cruzi. These findings illustrate the potential of fexinidazole as a drug candidate for the treatment of human CD. This study describes the in vivo activity of fexinidazole against Trypanosoma cruzi, the protozoan parasite causing Chagas disease, using mice infected with parasite strains with varying susceptibility to benznidazole, the standard treatment for Chagas. Fexinidazole and benznidazole were shown to have similar activity against benznidazolesusceptible and partially resistant T. cruzi strains (CL and Y), but fexinidazole had potent activity against benznidazole-resistant strains (VL-10 and Colombian). Fexinidazole treatment resulted in parasitological cure during acute disease phase in 88.9% of mice infected with the VL-10 strain and 78% with Colombian strain; benznidazole treatment did not result in cure in animals infected with these strains. Fexinidazole treatment was also shown to reduce myocarditis in all VL-10- and Colombian-infected animals, although parasite eradication was not achieved in all treated animals. These data demonstrate that it is possible to achieved better cure rates with fexinidazole in these experimental infection models than what is achieved with the standard benznidazole at the doses tested in this animal study benznidazole treatment regimen.
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32
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Phillips MA. Stoking the drug target pipeline for human African trypanosomiasis. Mol Microbiol 2012; 86:10-4. [PMID: 22925123 DOI: 10.1111/mmi.12001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2012] [Indexed: 11/28/2022]
Abstract
Trypanosoma brucei is the causative agent of African sleeping sickness, putting at risk up to 50 million people in sub-Saharan Africa. Current drug therapies are limited by toxicity and difficult treatment regimes and as the development of vaccines remains unlikely, the identification of better drugs to control this deadly disease is needed. Strategies for the identification of new lead compounds include phenotypic screening or target-based approaches. Implementation of the latter has been hampered by the lack of defined targets that are both essential and druggable. In this issue of Molecular Microbiology, Jones et al. (2012) report on the characterization of T. brucei pyridoxal kinase (PdxK), an enzyme required for the salvage of vitamin B6, an essential enzymatic cofactor. Genetic knock-down and small molecule inhibitor studies were used to demonstrate that PdxK is essential for parasite growth both in vitro and in a mouse model, providing both genetic and chemical validation of the target. An enzyme assay compatible with high-throughput screening (HTS) was developed and the X-ray crystal structure solved, showing the potential for species selective inhibition. These studies add a greatly needed additional target into the drug discovery pipeline for this deadly parasitic infection.
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Affiliation(s)
- Margaret A Phillips
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9041, USA.
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33
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Kennedy PG. An alternative form of melarsoprol in sleeping sickness. Trends Parasitol 2012; 28:307-10. [DOI: 10.1016/j.pt.2012.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/18/2012] [Accepted: 05/21/2012] [Indexed: 10/28/2022]
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34
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Seke Etet PF, Mahomoodally MF. New insights in staging and chemotherapy of African trypanosomiasis and possible contribution of medicinal plants. ScientificWorldJournal 2012; 2012:343652. [PMID: 22593674 PMCID: PMC3349134 DOI: 10.1100/2012/343652] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 11/16/2011] [Indexed: 11/17/2022] Open
Abstract
Human African trypanosomiasis (HAT) is a fatal if untreated fly-borne neuroinflammatory disease caused by protozoa of the species Trypanosoma brucei (T.b.). The increasing trend of HAT cases has been reversed, but according to WHO experts, new epidemics of this disease could appear. In addition, HAT is still a considerable burden for life quality and economy in 36 sub-Saharan Africa countries with 15-20 million persons at risk. Following joined initiatives of WHO and private partners, the fight against HAT was re-engaged, resulting in considerable breakthrough. We present here what is known at this day about HAT etiology and pathogenesis and the new insights in the development of accurate tools and tests for disease staging and severity monitoring in the field. Also, we elaborate herein the promising progresses made in the development of less toxic and more efficient trypanocidal drugs including the potential of medicinal plants and related alternative drug therapies.
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Affiliation(s)
- Paul F Seke Etet
- Department of Neurological Sciences (DNNMMS), University of Verona, Via Delle Grazie 8, 37134 Verona, Italy
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35
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Etet PFS, Palomba M, Colavito V, Grassi-Zucconi G, Bentivoglio M, Bertini G. Sleep and Rhythm Changes at the Time ofTrypanosoma bruceiInvasion of the Brain Parenchyma in the Rat. Chronobiol Int 2012; 29:469-81. [DOI: 10.3109/07420528.2012.660713] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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36
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Qiao Z, Wang Q, Zhang F, Wang Z, Bowling T, Nare B, Jacobs RT, Zhang J, Ding D, Liu Y, Zhou H. Chalcone–Benzoxaborole Hybrid Molecules as Potent Antitrypanosomal Agents. J Med Chem 2012; 55:3553-7. [DOI: 10.1021/jm2012408] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhitao Qiao
- School of
Pharmacy, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Qi Wang
- School of
Pharmacy, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Fenglong Zhang
- School of
Pharmacy, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Zhongli Wang
- School of
Pharmacy, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Tana Bowling
- SCYNEXIS, Inc., P.O. Box 12878,
Research Triangle Park, North Carolina 27709-2878, United States
| | - Bakela Nare
- SCYNEXIS, Inc., P.O. Box 12878,
Research Triangle Park, North Carolina 27709-2878, United States
| | - Robert T. Jacobs
- SCYNEXIS, Inc., P.O. Box 12878,
Research Triangle Park, North Carolina 27709-2878, United States
| | - Jiong Zhang
- School of
Pharmacy, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Dazhong Ding
- School of
Pharmacy, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Yangang Liu
- School of
Pharmacy, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Huchen Zhou
- School of
Pharmacy, Shanghai Jiao Tong University, 200240, Shanghai, China
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37
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Willert E, Phillips MA. Regulation and function of polyamines in African trypanosomes. Trends Parasitol 2011; 28:66-72. [PMID: 22192816 DOI: 10.1016/j.pt.2011.11.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 02/03/2023]
Abstract
The polyamine biosynthetic pathway is an important drug target for the treatment of human African trypanosomiasis (HAT), raising interest in understanding polyamine function and their mechanism of regulation. Polyamine levels are tightly controlled in mammalian cells, but similar regulatory mechanisms appear absent in trypanosomes. Instead trypanosomatid S-adenosylmethionine decarboxylase (AdoMetDC), which catalyzes a key step in the biosynthesis of the polyamine spermidine, is activated by dimerization with an inducible protein termed prozyme. Prozyme is an inactive paralog of the active AdoMetDC enzyme that evolved by gene duplication and is found only in the trypanosomatids. In Trypanosoma brucei, AdoMetDC activity appears to be controlled by regulation of prozyme protein levels, potentially at the translational level.
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Affiliation(s)
- Erin Willert
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Road, Dallas, TX 75390-9041, USA
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38
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Yan GZ, Generaux CN, Yoon M, Goldsmith RB, Tidwell RR, Hall JE, Olson CA, Clewell HJ, Brouwer KLR, Paine MF. A semiphysiologically based pharmacokinetic modeling approach to predict the dose-exposure relationship of an antiparasitic prodrug/active metabolite pair. Drug Metab Dispos 2011; 40:6-17. [PMID: 21953913 DOI: 10.1124/dmd.111.040063] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Dose selection during antiparasitic drug development in animal models and humans traditionally has relied on correlations between plasma concentrations obtained at or below maximally tolerated doses that are efficacious. The objective of this study was to improve the understanding of the relationship between dose and plasma/tissue exposure of the model antiparasitic agent, pafuramidine, using a semiphysiologically based pharmacokinetic (semi-PBPK) modeling approach. Preclinical and clinical data generated during the development of pafuramidine, a prodrug of the active metabolite, furamidine, were used. A whole-body semi-PBPK model for rats was developed based on a whole-liver PBPK model using rat isolated perfused liver data. A whole-body semi-PBPK model for humans was developed on the basis of the whole-body rat model. Scaling factors were calculated using metabolic and transport clearance data generated from rat and human sandwich-cultured hepatocytes. Both whole-body models described pafuramidine and furamidine disposition in plasma and predicted furamidine tissue (liver and kidney) exposure and excretion profiles (biliary and renal). The whole-body models predicted that the intestine contributes significantly (30-40%) to presystemic furamidine formation in both rats and humans. The predicted terminal elimination half-life of furamidine in plasma was 3- to 4-fold longer than that of pafuramidine in rats (170 versus 47 h) and humans (64 versus 19 h). The dose-plasma/tissue exposure relationship for the prodrug/active metabolite pair was determined using the whole-body models. The human model proposed a dose regimen of pafuramidine (40 mg once daily) based on a predefined efficacy-safety index. A similar approach could be used to guide dose-ranging studies in humans for next-in-class compounds.
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Affiliation(s)
- Grace Zhixia Yan
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7569, USA
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Rodgers J, Jones A, Gibaud S, Bradley B, McCabe C, Barrett MP, Gettinby G, Kennedy PGE. Melarsoprol cyclodextrin inclusion complexes as promising oral candidates for the treatment of human African trypanosomiasis. PLoS Negl Trop Dis 2011; 5:e1308. [PMID: 21909447 PMCID: PMC3167784 DOI: 10.1371/journal.pntd.0001308] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 07/23/2011] [Indexed: 12/02/2022] Open
Abstract
Human African trypanosomiasis (HAT), or sleeping sickness, results from infection with the protozoan parasites Trypanosoma brucei (T. b.) gambiense or T. b. rhodesiense and is invariably fatal if untreated. There are 60 million people at risk from the disease throughout sub-Saharan Africa. The infection progresses from the haemolymphatic stage where parasites invade the blood, lymphatics and peripheral organs, to the late encephalitic stage where they enter the central nervous system (CNS) to cause serious neurological disease. The trivalent arsenical drug melarsoprol (Arsobal) is the only currently available treatment for CNS-stage T. b. rhodesiense infection. However, it must be administered intravenously due to the presence of propylene glycol solvent and is associated with numerous adverse reactions. A severe post-treatment reactive encephalopathy occurs in about 10% of treated patients, half of whom die. Thus melarsoprol kills 5% of all patients receiving it. Cyclodextrins have been used to improve the solubility and reduce the toxicity of a wide variety of drugs. We therefore investigated two melarsoprol cyclodextrin inclusion complexes; melarsoprol hydroxypropyl-β-cyclodextrin and melarsoprol randomly-methylated-β-cyclodextrin. We found that these compounds retain trypanocidal properties in vitro and cure CNS-stage murine infections when delivered orally, once per day for 7-days, at a dosage of 0.05 mmol/kg. No overt signs of toxicity were detected. Parasite load within the brain was rapidly reduced following treatment onset and magnetic resonance imaging showed restoration of normal blood-brain barrier integrity on completion of chemotherapy. These findings strongly suggest that complexed melarsoprol could be employed as an oral treatment for CNS-stage HAT, delivering considerable improvements over current parenteral chemotherapy.
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Affiliation(s)
- Jean Rodgers
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Amy Jones
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Stéphane Gibaud
- Laboratoire de Pharmacie Clinique, Nancy Université, Nancy, France
| | - Barbara Bradley
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Christopher McCabe
- Institute of Neuroscience and Psychology, Glasgow Experimental MRI Centre, University of Glasgow, Glasgow, United Kingdom
| | - Michael P. Barrett
- Wellcome Trust Centre of Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - George Gettinby
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, United Kingdom
| | - Peter G. E. Kennedy
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Activation and inhibition of CTP synthase from Trypanosoma brucei, the causative agent of African sleeping sickness. Bioorg Med Chem Lett 2011; 21:5188-90. [DOI: 10.1016/j.bmcl.2011.07.054] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 07/13/2011] [Accepted: 07/13/2011] [Indexed: 11/19/2022]
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Brun R, Don R, Jacobs RT, Wang MZ, Barrett MP. Development of novel drugs for human African trypanosomiasis. Future Microbiol 2011; 6:677-91. [DOI: 10.2217/fmb.11.44] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Human African trypanosomiasis (HAT) or ‘sleeping sickness’ is a neglected tropical disease caused by the parasite Trypanosoma brucei. Novel models for funding pharmaceutical development against HAT are beginning to yield results. The Drugs for Neglected Diseases initiative (DNDi) rediscovered a nitroimidazole, fexinidazole, which is currently in Phase I clinical trials. Novel benzoxaboroles, discovered by Anacor, Scynexis and DNDi, have good pharmacokinetic properties in plasma and in the brain and are curative in a murine model of stage two HAT with brain infection. The Consortium for Parasitic Drug Development (CPDD) has identified a series of dicationic compounds that can cure a monkey model of stage two HAT. With other screening programs yielding hits, the pipeline for new HAT drugs might finally begin to fill.
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Affiliation(s)
- Reto Brun
- Department Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, and, University of Basel, CH-4002 Basel, Switzerland
| | - Robert Don
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
| | - Robert T Jacobs
- Department of Chemistry, SCYNEXIS, Inc., PO Box 12878, Research Triangle Park, NC, 27709-2878, USA
| | - Michael Zhuo Wang
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA
| | - Michael P Barrett
- Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, Scotland
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Yan GZ, Brouwer KLR, Pollack GM, Wang MZ, Tidwell RR, Hall JE, Paine MF. Mechanisms underlying differences in systemic exposure of structurally similar active metabolites: comparison of two preclinical hepatic models. J Pharmacol Exp Ther 2011; 337:503-12. [PMID: 21320872 DOI: 10.1124/jpet.110.177220] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Selection of in vitro models that accurately characterize metabolite systemic and hepatobiliary exposure remains a challenge in drug development. In the present study, mechanisms underlying differences in systemic exposure of two active metabolites, furamidine and 2,5-bis (5-amidino)-2-pyridyl furan (CPD-0801), were examined using two hepatic models from rats: isolated perfused livers (IPLs) and sandwich-cultured hepatocytes (SCH). Pafuramidine, a prodrug of furamidine, and 2,5-bis [5-(N-methoxyamidino)-2-pyridyl] furan (CPD-0868), a prodrug of CPD-0801, were selected for investigation because CPD-0801 exhibits greater systemic exposure than furamidine, despite remarkable structural similarity between these two active metabolites. In both IPLs and SCH, the extent of conversion of CPD-0868 to CPD-0801 was consistently higher than that of pafuramidine to furamidine over time (at most 2.5-fold); area under the curve (AUC) of CPD-0801 in IPL perfusate and SCH medium was at least 7-fold higher than that of furamidine. Pharmacokinetic modeling revealed that the rate constant for basolateral (liver to blood) net efflux (k(A_net efflux)) of total formed CPD-0801 (bound + unbound) was 6-fold higher than that of furamidine. Hepatic accumulation of both active metabolites was extensive (>95% of total formed); the hepatic unbound fraction (f(u,L)) of CPD-0801 was 5-fold higher than that of furamidine (1.6 versus 0.3%). Incorporation of f(u,L) into the pharmacokinetic model resulted in comparable k(A_net efflux,u) between furamidine and CPD-0801. In conclusion, intrahepatic binding markedly influenced the disposition of these active metabolites. A higher f(u,L) explained, in part, the enhanced perfusate AUC of CPD-0801 compared with furamidine in IPLs. SCH predicted the disposition of prodrug/metabolite in IPLs.
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Affiliation(s)
- Grace Zhixia Yan
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599-7569, USA
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Grady SC, Messina JP, McCord PF. Population vulnerability and disability in Kenya's tsetse fly habitats. PLoS Negl Trop Dis 2011; 5:e957. [PMID: 21347453 PMCID: PMC3035673 DOI: 10.1371/journal.pntd.0000957] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 01/07/2011] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Human African Trypanosomiasis (HAT), also referred to as sleeping sickness, and African Animal Trypanosomaisis (AAT), known as nagana, are highly prevalent parasitic vector-borne diseases in sub-Saharan Africa. Humans acquire trypanosomiasis following the bite of a tsetse fly infected with the protozoa Trypanosoma brucei (T.b.) spp. -i.e., T.b. gambiense in West and Central Africa and T.b. rhodesiense in East and Southern Africa. Over the last decade HAT diagnostic capacity to estimate HAT prevalence has improved in active case-finding areas but enhanced passive surveillance programs are still lacking in much of rural sub-Saharan Africa. METHODOLOGY/PRINCIPAL FINDINGS This retrospective-cross-sectional study examined the use of national census data (1999) to estimate population vulnerability and disability in Kenya's 7 tsetse belts to assess the potential of HAT-acquired infection in those areas. A multilevel study design estimated the likelihood of disability in individuals, nested within households, nested within tsetse fly habitats of varying levels of poverty. Residents and recent migrants of working age were studied. Tsetse fly's impact on disability was conceptualised via two exposure pathways: directly from the bite of a pathogenic tsetse fly resulting in HAT infection or indirectly, as the potential for AAT takes land out of agricultural production and diseased livestock leads to livestock morbidity and mortality, contributing to nutritional deficiencies and poverty. Tsetse belts that were significantly associated with increased disability prevalence were identified and the direct and indirect exposure pathways were evaluated. CONCLUSIONS/SIGNIFICANCE Incorporating reports on disability from the national census is a promising surveillance tool that may enhance future HAT surveillance programs in sub-Saharan Africa. The combined burdens of HAT and AAT and the opportunity costs of agricultural production in AAT areas are likely contributors to disability within tsetse-infested areas. Future research will assess changes in the spatial relationships between high tsetse infestation and human disability following the release of the Kenya 2009 census at the local level.
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Affiliation(s)
- Sue C Grady
- Department of Geography, Michigan State University, East Lansing, Michigan, United States of America.
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