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Milanes JE, Kwain S, Drawdy A, Dodson L, Monaghan MT, Rice CA, Dominy BN, Whitehead DC, Morris JC. Glucose metabolism in the pathogenic free-living amoebae: Tempting targets for treatment development. Chem Biol Drug Des 2024; 103:e14377. [PMID: 37864277 PMCID: PMC10843269 DOI: 10.1111/cbdd.14377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/18/2023] [Accepted: 10/04/2023] [Indexed: 10/22/2023]
Abstract
Pathogenic free-living amoebae (pFLA) are single-celled eukaryotes responsible for causing intractable infections with high morbidity and mortality in humans and animals. Current therapeutic approaches include cocktails of antibiotic, antifungal, and antimicrobial compounds. Unfortunately, the efficacy of these can be limited, driving the need for the discovery of new treatments. Pan anti-amebic agents would be ideal; however, identifying these agents has been a challenge, likely due to the limited evolutionary relatedness of the different pFLA. Here, we discuss the potential of targeting amoebae glucose metabolic pathways as the differences between pFLA and humans suggest specific inhibitors could be developed as leads for new therapeutics.
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Affiliation(s)
- Jillian E. Milanes
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
| | - Samuel Kwain
- Eukaryotic Pathogens Innovation Center, Department of Chemistry, Clemson University, Clemson SC 29634
| | - Allyson Drawdy
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
| | - Laura Dodson
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
| | - Matthew T. Monaghan
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
| | - Christopher A. Rice
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907
- Purdue Institute for Drug Discovery (PIDD), Purdue University, West Lafayette, IN 47907
- Purdue Institute of Inflammation, Immunology and Infectious Disease (PI4D), Purdue University, West Lafayette, IN 47907
| | - Brian N. Dominy
- Department of Chemistry, Clemson University, Clemson SC 29634
| | - Daniel C. Whitehead
- Eukaryotic Pathogens Innovation Center, Department of Chemistry, Clemson University, Clemson SC 29634
| | - James C. Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634
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Roster CP, LaVigne D, Milanes JE, Knight E, Anderson HD, Pizarro S, Harding EM, Morris MT, Yan VC, Pham CD, Muller F, Kwain S, Rees KC, Dominy B, Whitehead DC, Uddin MN, Millward SW, Morris JC. Enolase Inhibitors as Early Lead Therapeutics against Trypanosoma brucei. Pathogens 2023; 12:1290. [PMID: 38003754 PMCID: PMC10675445 DOI: 10.3390/pathogens12111290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/16/2023] [Accepted: 10/25/2023] [Indexed: 11/26/2023] Open
Abstract
Glucose metabolism is critical for the African trypanosome, Trypanosoma brucei, serving as the lone source of ATP production for the bloodstream form (BSF) parasite in the glucose-rich environment of the host blood. Recently, phosphonate inhibitors of human enolase (ENO), the enzyme responsible for the interconversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP) in glycolysis or PEP to 2-PG in gluconeogenesis, have been developed for the treatment of glioblastoma multiforme (GBM). Here, we have tested these agents against T. brucei ENO (TbENO) and found the compounds to be potent enzyme inhibitors and trypanocides. For example, (1-hydroxy-2-oxopyrrolidin-3-yl) phosphonic acid (deoxy-SF2312) was a potent enzyme inhibitor (IC50 value of 0.60 ± 0.23 µM), while a six-membered ring-bearing phosphonate, (1-hydroxy-2-oxopiperidin-3-yl) phosphonic acid (HEX), was less potent (IC50 value of 2.1 ± 1.1 µM). An analog with a larger seven-membered ring, (1-hydroxy-2-oxoazepan-3-yl) phosphonic acid (HEPTA), was not active. Molecular docking simulations revealed that deoxy-SF2312 and HEX had binding affinities of -6.8 and -7.5 kcal/mol, respectively, while the larger HEPTA did not bind as well, with a binding of affinity of -4.8 kcal/mol. None of these compounds were toxic to BSF parasites; however, modification of enzyme-active phosphonates through the addition of pivaloyloxymethyl (POM) groups improved activity against T. brucei, with POM-modified (1,5-dihydroxy-2-oxopyrrolidin-3-yl) phosphonic acid (POMSF) and POMHEX having EC50 values of 0.45 ± 0.10 and 0.61 ± 0.08 µM, respectively. These findings suggest that HEX is a promising lead against T. brucei and that further development of prodrug HEX analogs is warranted.
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Affiliation(s)
- Colm P. Roster
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
| | - Danielle LaVigne
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
| | - Jillian E. Milanes
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
| | - Emily Knight
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
| | - Heidi D. Anderson
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
| | - Sabrina Pizarro
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
| | - Elijah M. Harding
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
| | - Meredith T. Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
| | - Victoria C. Yan
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA; (V.C.Y.); (C.-D.P.); (M.N.U.); (S.W.M.)
| | - Cong-Dat Pham
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA; (V.C.Y.); (C.-D.P.); (M.N.U.); (S.W.M.)
| | - Florian Muller
- Sporos Bioventures, 3000 Bissonnet, Belmont Suite 5303, Houston, TX 77005, USA;
| | - Samuel Kwain
- Eukaryotic Pathogens Innovation Center, Department of Chemistry, Clemson University, Clemson, SC 29634, USA; (S.K.); (K.C.R.); (D.C.W.)
| | - Kerrick C. Rees
- Eukaryotic Pathogens Innovation Center, Department of Chemistry, Clemson University, Clemson, SC 29634, USA; (S.K.); (K.C.R.); (D.C.W.)
| | - Brian Dominy
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA;
| | - Daniel C. Whitehead
- Eukaryotic Pathogens Innovation Center, Department of Chemistry, Clemson University, Clemson, SC 29634, USA; (S.K.); (K.C.R.); (D.C.W.)
| | - Md Nasir Uddin
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA; (V.C.Y.); (C.-D.P.); (M.N.U.); (S.W.M.)
| | - Steven W. Millward
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX 77030, USA; (V.C.Y.); (C.-D.P.); (M.N.U.); (S.W.M.)
| | - James C. Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA; (C.P.R.); (D.L.); (J.E.M.); (E.K.); (H.D.A.); (S.P.); (E.M.H.); (M.T.M.)
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Nagode A, Vanbeselaere J, Dutkiewicz Z, Kaltenbrunner S, Wilson IBH, Duchêne M. Molecular characterisation of Entamoeba histolytica UDP-glucose 4-epimerase, an enzyme able to provide building blocks for cyst wall formation. PLoS Negl Trop Dis 2023; 17:e0011574. [PMID: 37616327 PMCID: PMC10482301 DOI: 10.1371/journal.pntd.0011574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 09/06/2023] [Accepted: 08/06/2023] [Indexed: 08/26/2023] Open
Abstract
In the human host, the protozoan parasite Entamoeba histolytica is adapted to a non-invasive lifestyle in the colon as well as to an invasive lifestyle in the mesenterial blood vessels and the liver. This means to cope with bacteria and human cells as well as various metabolic challenges. Galactose and N-acetylgalactosamine (GalNAc) are sugars of great importance for the amoebae, they attach to the host mucus and enterocytes via their well-studied Gal/GalNAc specific lectin, they carry galactose residues in their surface glycans, and they cleave GalNAc from host mucins. The enzyme UDP-glucose 4-epimerase (GalE) works as a bridge between the galactose and glucose worlds, it can help to generate glucose for glycolysis from phagocytosis products containing galactose as well as providing UDP-galactose necessary for the biosynthesis of galactose-containing surface components. E. histolytica contains a single galE gene. We recombinantly expressed the enzyme in Escherichia coli and used a spectrophotometric assay to determine its temperature and pH dependency (37°C, pH 8.5), its kinetics for UDP-glucose (Km = 31.82 μM, Vmax = 4.31 U/mg) and substrate spectrum. As observed via RP-HPLC, the enzyme acts on UDP-Glc/Gal as well as UDP-GlcNAc/GalNAc. Previously, Trypanosoma brucei GalE and the bloodstream form of the parasite were shown to be susceptible to the three compounds ebselen, a selenoorganic drug with antioxidant properties, diethylstilbestrol, a mimic of oestrogen with anti-inflammatory properties, and ethacrynic acid, a loop diuretic used to treat oedema. In this study, the three compounds had cytotoxic activity against E. histolytica, but only ebselen inhibited the recombinant GalE with an IC50 of 1.79 μM (UDP-Gal) and 1.2 μM (UDP-GalNAc), suggesting that the two other compounds are active against other targets in the parasite. The importance of the ability of GalE to interconvert UDP-GalNAc and UDP-GlcNAc may be that the trophozoites can generate precursors for their own cyst wall from the sugar subunits cleaved from host mucins. This finding advances our understanding of the biochemical interactions of E. histolytica in its colonic environment.
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Affiliation(s)
- Anna Nagode
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | | | | | - Samantha Kaltenbrunner
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Iain B. H. Wilson
- Department of Chemistry, Universität für Bodenkultur, Vienna, Austria
| | - Michael Duchêne
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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Wang D, Li R, Wu YX, Fan XY, Liu XY, Yang F, Zhang TT, Ma JY, Hu YH. Molecular characterization of hexokinase (HK) in Haemaphysalis longicornis and evaluation of HK protein- and DNA-based vaccines against adult ticks. PEST MANAGEMENT SCIENCE 2023; 79:1721-1730. [PMID: 36606406 DOI: 10.1002/ps.7346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 12/14/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Haemaphysalis longicornis is an obligate hematophagous ectoparasite, which transmits various pathogens to humans, livestock and wild animals. Hexokinase (HK) is a key regulatory enzyme of the glycolytic pathway in the organisms. However, little is known about hexokinase and its functions in ticks. RESULTS The open reading frame of the H. longicornis HK (HlHK) gene was 1425 bp and encoded a protein of 474 amino acids, containing conserved domains for glucose, glucose 6-phosphate, and adenosine triphosphate. The expression of HlHK gene was detected at different developmental stages and in different tissues of unfed female ticks. Enzyme-linked immunosorbent assay revealed that both HK protein- and DNA-based vaccines increased the antibody levels of the immunized animals. A vaccination trail on rabbits against H. longicornis infestation indicated that the rHlHK protein and HlHK DNA vaccines reduced the number of attached female ticks by 9% and 12%, egg mass weight by 36% and 34%, and egg hatching rate by 41% and 17%, respectively. Overall, protein vaccination conferred 65.6% protection against adult female ticks, whereas the DNA vaccine conferred 51.8% protection. CONCLUSION This is the first report of the molecular characterization of the HK protein and sequencing of the HK gene from H. longicornis. Positive results from vaccination trials on rabbits of the recombinant HK protein and HK DNA suggest that these novel anti-tick vaccines potentially can be used as viable tick control tools for the management of the Asian longhorned tick. Additionally, inhibition of glucose metabolism may be a new strategy for tick control. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Duo Wang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Ru Li
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Ya-Xue Wu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Xiang-Yuan Fan
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Xiao-Ya Liu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Feng Yang
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Tian-Tian Zhang
- Institute of Paleontology, Hebei GEO University, Shijiazhuang, China
| | - Jing-Yi Ma
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Yong-Hong Hu
- Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, Hebei Collaborative Innovation Center for Eco-Environment, Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
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Krishna CK, Franke L, Erdmann R, Kalel VC. Isolation of Glycosomes from Trypanosoma brucei. Methods Mol Biol 2023; 2643:33-45. [PMID: 36952176 DOI: 10.1007/978-1-0716-3048-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Glycosomes, belonging to the sub-class of peroxisomes, are single-membrane-bound organelles of trypanosomatid parasites. Glycosomes compartmentalize mainly glycolytic and other essential metabolic pathways such as gluconeogenesis, pentose phosphate pathway, sugar nucleotide biosynthesis, etc. Since glycosomes are parasite-specific and their biogenesis is essential for the parasite survival, they have attracted a lot of interest over the years. Understanding the glycosomal enzyme composition and machinery involved in the biogenesis of this organelle requires the knowledge of the glycosomal proteome. Here we describe a method to isolate highly purified glycosomes and further enrichment of the glycosomal membrane proteins from the pro-cyclic form of Trypanosoma brucei. The isolation method is based on the controlled rupture of the cells by silicon carbide, followed by the differential centrifugation, and density gradient centrifugation. Further, the glycosomal membrane proteins are enriched from the purified glycosomes by the successive treatments with low-salt, high-salt, and alkaline carbonate buffer extractions.
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Affiliation(s)
- Chethan K Krishna
- Institute for Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Faculty of Medicine, Ruhr University of Bochum, Bochum, Germany
| | - Laura Franke
- Institute for Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Faculty of Medicine, Ruhr University of Bochum, Bochum, Germany
| | - Ralf Erdmann
- Institute for Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Faculty of Medicine, Ruhr University of Bochum, Bochum, Germany.
| | - Vishal C Kalel
- Institute for Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Faculty of Medicine, Ruhr University of Bochum, Bochum, Germany.
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Benítez D, Franco J, Sardi F, Leyva A, Durán R, Choi G, Yang G, Kim T, Kim N, Heo J, Kim K, Lee H, Choi I, Radu C, Shum D, No JH, Comini MA. Drug-like molecules with anti-trypanothione synthetase activity identified by high throughput screening. J Enzyme Inhib Med Chem 2022; 37:912-929. [PMID: 35306933 PMCID: PMC8942522 DOI: 10.1080/14756366.2022.2045590] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Trypanothione synthetase (TryS) catalyses the synthesis of N1,N8-bis(glutathionyl)spermidine (trypanothione), which is the main low molecular mass thiol supporting several redox functions in trypanosomatids. TryS attracts attention as molecular target for drug development against pathogens causing severe and fatal diseases in mammals. A drug discovery campaign aimed to identify and characterise new inhibitors of TryS with promising biological activity was conducted. A large compound library (n = 51,624), most of them bearing drug-like properties, was primarily screened against TryS from Trypanosoma brucei (TbTryS). With a true-hit rate of 0.056%, several of the TbTryS hits (IC50 from 1.2 to 36 µM) also targeted the homologue enzyme from Leishmania infantum and Trypanosoma cruzi (IC50 values from 2.6 to 40 µM). Calmidazolium chloride and Ebselen stand out for their multi-species anti-TryS activity at low µM concentrations (IC50 from 2.6 to 13.8 µM). The moieties carboxy piperidine amide and amide methyl thiazole phenyl were identified as novel TbTryS inhibitor scaffolds. Several of the TryS hits presented one-digit µM EC50 against T. cruzi and L. donovani amastigotes but proved cytotoxic against the human osteosarcoma and macrophage host cells (selectivity index ≤ 3). In contrast, seven hits showed a significantly higher selectivity against T. b. brucei (selectivity index from 11 to 182). Non-invasive redox assays confirmed that Ebselen, a multi-TryS inhibitor, induces an intracellular oxidative milieu in bloodstream T. b. brucei. Kinetic and mass spectrometry analysis revealed that Ebselen is a slow-binding inhibitor that modifies irreversible a highly conserved cysteine residue from the TryS’s synthetase domain. The most potent TbTryS inhibitor (a singleton containing an adamantine moiety) exerted a non-covalent, non-competitive (with any of the substrates) inhibition of the enzyme. These data feed the drug discovery pipeline for trypanosomatids with novel and valuable information on chemical entities with drug potential.
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Affiliation(s)
- Diego Benítez
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Jaime Franco
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Florencia Sardi
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Alejandro Leyva
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Rosario Durán
- Analytical Biochemistry and Proteomics Unit, Institut Pasteur de Montevideo, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Gahee Choi
- Host-Parasite Research Laboratory, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Gyongseon Yang
- Host-Parasite Research Laboratory, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Taehee Kim
- Assay Development and Screening, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Namyoul Kim
- Assay Development and Screening, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Jinyeong Heo
- Assay Development and Screening, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Kideok Kim
- Automation and Logistics Management, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Honggun Lee
- Automation and Logistics Management, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Inhee Choi
- Medicinal Chemistry, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Constantin Radu
- Automation and Logistics Management, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - David Shum
- Assay Development and Screening, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Joo Hwan No
- Host-Parasite Research Laboratory, Institut Pasteur Korea, Gyeonggi-do, Republic of Korea
| | - Marcelo A Comini
- Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
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Parab AR, McCall LI. Tryp-ing Up Metabolism: Role of Metabolic Adaptations in Kinetoplastid Disease Pathogenesis. Infect Immun 2021; 89:e00644-20. [PMID: 33526564 PMCID: PMC8090971 DOI: 10.1128/iai.00644-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Today, more than a billion people-one-sixth of the world's population-are suffering from neglected tropical diseases. Human African trypanosomiasis, Chagas disease, and leishmaniasis are neglected tropical diseases caused by protozoan parasites belonging to the genera Trypanosoma and Leishmania About half a million people living in tropical and subtropical regions of the world are at risk of contracting one of these three infections. Kinetoplastids have complex life cycles with different morphologies and unique physiological requirements at each life cycle stage. This review covers the latest findings on metabolic pathways impacting disease pathogenesis of kinetoplastids within the mammalian host. Nutrient availability is a key factor shaping in vivo parasite metabolism; thus, kinetoplastids display significant metabolic flexibility. Proteomic and transcriptomic profiles show that intracellular trypanosomatids are able to switch to an energy-efficient metabolism within the mammalian host system. Host metabolic changes can also favor parasite persistence, and contribute to symptom development, in a location-specific fashion. Ultimately, targeted and untargeted metabolomics studies have been a valuable approach to elucidate the specific biochemical pathways affected by infection within the host, leading to translational drug development and diagnostic insights.
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Affiliation(s)
- Adwaita R Parab
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Laura-Isobel McCall
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
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Proposed Mechanism for the Antitrypanosomal Activity of Quercetin and Myricetin Isolated from Hypericum afrum Lam.: Phytochemistry, In Vitro Testing and Modeling Studies. Molecules 2021; 26:molecules26041009. [PMID: 33672916 PMCID: PMC7918497 DOI: 10.3390/molecules26041009] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/10/2021] [Accepted: 02/10/2021] [Indexed: 11/24/2022] Open
Abstract
The in vitro activity of L. donovani (promastigotes, axenic amastigotes and intracellular amastigotes in THP1 cells) and T. brucei, from the fractions obtained from the hydroalcoholic extract of the aerial part of Hypericum afrum and the isolated compounds, has been evaluated. The chloroform, ethyl acetate and n-butanol extracts showed significant antitrypanosomal activity towards T. brucei, with IC50 values of 12.35, 13.53 and 12.93 µg/mL and with IC90 values of 14.94, 19.31 and 18.67 µg/mL, respectively. The phytochemical investigation of the fractions led to the isolation and identification of quercetin (1), myricitrin (2), biapigenin (3), myricetin (4), hyperoside (5), myricetin-3-O-β-d-galactopyranoside (6) and myricetin-3’-O-β-d-glucopyranoside (7). Myricetin-3’-O-β-d-glucopyranoside (7) has been isolated for the first time from this genus. The chemical structures were elucidated by using comprehensive one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) spectroscopic data, as well as high-resolution electrospray ionization mass spectrometry (HR-ESI–MS). These compounds have also been evaluated for their antiprotozoal activity. Quercetin (1) and myricetin (4) showed noteworthy activity against T. brucei, with IC50 and IC90 values of 7.52 and 5.71 µM, and 9.76 and 7.97 µM, respectively. The T. brucei hexokinase (TbHK1) enzyme was further explored as a potential target of quercetin and myricetin, using molecular modeling studies. This proposed mechanism assists in the exploration of new candidates for novel antitrypanosomal drugs.
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Xin Q, Yuan M, Lv W, Li H, Song X, Lu J, Jing T. Molecular characterization and serodiagnostic potential of Echinococcus granulosus hexokinase. Parasit Vectors 2021; 14:105. [PMID: 33557934 PMCID: PMC7869421 DOI: 10.1186/s13071-021-04606-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/23/2021] [Indexed: 11/12/2022] Open
Abstract
Background Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus (sensu stricto), is a life-threatening but neglected zoonosis. Glycolytic enzymes are crucial molecules for the survival and development of E. granulosus. The aim of this study was to investigate the molecular characterization, immunogenicity, tissue distribution and serodiagnostic potential of E. granulosus hexokinase (EgHK), the first key enzyme in the glycolytic pathway. Methods EgHK was cloned and expressed in Escherichia coli. Specific serum antibodies were evaluated in mice immunized with recombinant EgHK (rEgHK). The location of EgHK in the larval stage of E. granulosus was determined using fluorescence immunohistochemistry, and the potential of rEgHK as a diagnostic antigen was investigated in patients with CE using indirect enzyme-linked immunosorbent assay (ELISA). Results Recombinant EgHK could be identified in the sera of patients with CE and in mouse anti-rEgHK sera. High titers of specific immunoglobulin G were induced in mice after immunization with rEgHK. EgHK was mainly located in the tegument, suckers and hooklets of protoscoleces and in the germinal layer and laminated layer of the cyst wall. The sensitivity and specificity of the rEgHK-ELISA reached 91.3% (42/46) and 87.8% (43/49), respectively. Conclusions We have characterized the sequence, structure and location of EgHK and investigated the immunoreactivity, immunogenicity and serodiagnostic potential of rEgHK. Our results suggest that EgHK may be a promising candidate for the development of vaccines against E. granulosus and an effective antigen for the diagnosis of human CE.![]()
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Affiliation(s)
- Qi Xin
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, Gansu, People's Republic of China
| | - Miaomiao Yuan
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, Gansu, People's Republic of China.,The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, 518000, Guangdong, People's Republic of China
| | - Wei Lv
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, Gansu, People's Republic of China
| | - Huanping Li
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, Gansu, People's Republic of China
| | - Xiaoxia Song
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, Gansu, People's Republic of China
| | - Jun Lu
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, Gansu, People's Republic of China
| | - Tao Jing
- Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, Gansu, People's Republic of China.
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10
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Garcia SN, Guedes RC, Marques MM. Unlocking the Potential of HK2 in Cancer Metabolism and Therapeutics. Curr Med Chem 2020; 26:7285-7322. [PMID: 30543165 DOI: 10.2174/0929867326666181213092652] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/26/2018] [Accepted: 11/06/2018] [Indexed: 12/24/2022]
Abstract
Glycolysis is a tightly regulated process in which several enzymes, such as Hexokinases (HKs), play crucial roles. Cancer cells are characterized by specific expression levels of several isoenzymes in different metabolic pathways and these features offer possibilities for therapeutic interventions. Overexpression of HKs (mostly of the HK2 isoform) have been consistently reported in numerous types of cancer. Moreover, deletion of HK2 has been shown to decrease cancer cell proliferation without explicit side effects in animal models, which suggests that targeting HK2 is a viable strategy for cancer therapy. HK2 inhibition causes a substantial decrease of glycolysis that affects multiple pathways of central metabolism and also destabilizes the mitochondrial outer membrane, ultimately enhancing cell death. Although glycolysis inhibition has met limited success, partly due to low selectivity for specific isoforms and excessive side effects of the reported HK inhibitors, there is ample ground for progress. The current review is focused on HK2 inhibition, envisaging the development of potent and selective anticancer agents. The information on function, expression, and activity of HKs is presented, along with their structures, known inhibitors, and reported effects of HK2 ablation/inhibition. The structural features of the different isozymes are discussed, aiming to stimulate a more rational approach to the design of selective HK2 inhibitors with appropriate drug-like properties. Particular attention is dedicated to a structural and sequence comparison of the structurally similar HK1 and HK2 isoforms, aiming to unveil differences that could be explored therapeutically. Finally, several additional catalytic- and non-catalytic roles on different pathways and diseases, recently attributed to HK2, are reviewed and their implications briefly discussed.
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Affiliation(s)
- Sara N Garcia
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.,iMed.ULisboa, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Rita C Guedes
- iMed.ULisboa, Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - M Matilde Marques
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
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11
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Abstract
AbstractDuring three decades, only about 20 new drugs have been developed for malaria, tuberculosis and all neglected tropical diseases (NTDs). This critical situation was reached because NTDs represent only 10% of health research investments; however, they comprise about 90% of the global disease burden. Computational simulations applied in virtual screening (VS) strategies are very efficient tools to identify pharmacologically active compounds or new indications for drugs already administered for other diseases. One of the advantages of this approach is the low time-consuming and low-budget first stage, which filters for testing experimentally a group of candidate compounds with high chances of binding to the target and present trypanocidal activity. In this work, we review the most common VS strategies that have been used for the identification of new drugs with special emphasis on those applied to trypanosomiasis and leishmaniasis. Computational simulations based on the selected protein targets or their ligands are explained, including the method selection criteria, examples of successful VS campaigns applied to NTDs, a list of validated molecular targets for drug development and repositioned drugs for trypanosomatid-caused diseases. Thereby, here we present the state-of-the-art of VS and drug repurposing to conclude pointing out the future perspectives in the field.
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12
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Enzymatic and Structural Characterization of the Naegleria fowleri Glucokinase. Antimicrob Agents Chemother 2019; 63:AAC.02410-18. [PMID: 30783001 DOI: 10.1128/aac.02410-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/08/2019] [Indexed: 02/07/2023] Open
Abstract
Infection with the free-living amoeba Naegleria fowleri leads to life-threatening primary amoebic meningoencephalitis. Efficacious treatment options for these infections are limited, and the mortality rate is very high (∼98%). Parasite metabolism may provide suitable targets for therapeutic design. Like most other organisms, glucose metabolism is critical for parasite viability, being required for growth in culture. The first enzyme required for glucose metabolism is typically a hexokinase (HK), which transfers a phosphate from ATP to glucose. The products of this enzyme are required for both glycolysis and the pentose phosphate pathway. However, the N. fowleri genome lacks an obvious HK homolog and instead harbors a glucokinase (Glck). The N. fowleri Glck (NfGlck) shares limited (25%) amino acid identity with the mammalian host enzyme (Homo sapiens Glck), suggesting that parasite-specific inhibitors with anti-amoeba activity can be generated. Following heterologous expression, NfGlck was found to have a limited hexose substrate range, with the greatest activity observed with glucose. The enzyme had apparent Km values of 42.5 ± 7.3 μM and 141.6 ± 9.9 μM for glucose and ATP, respectively. The NfGlck structure was determined and refined to 2.2-Å resolution, revealing that the enzyme shares greatest structural similarity with the Trypanosoma cruzi Glck. These similarities include binding modes and binding environments for substrates. To identify inhibitors of NfGlck, we screened a small collection of inhibitors of glucose-phosphorylating enzymes and identified several small molecules with 50% inhibitory concentration values of <1 μM that may prove useful as hit chemotypes for further leads and therapeutic development against N. fowleri.
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13
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Abstract
SIGNIFICANCE Hexokinases are key enzymes that are responsible for the first reaction of glycolysis, but they also moonlight other cellular processes, including mitochondrial redox signaling regulation. Modulation of hexokinase activity and spatiotemporal location by reactive oxygen and nitrogen species as well as other gasotransmitters serves as the basis for a unique, underexplored method of tight and flexible regulation of these fundamental enzymes. Recent Advances: Redox modifications of thiols serve as a molecular code that enables the precise and complex regulation of hexokinases. Redox regulation of hexokinases is also used by multiple parasites to cause widespread and severe diseases, including malaria, Chagas disease, and sleeping sickness. Redox-active molecules affect each other, and the moonlighting activity of hexokinases provides another feedback loop that affects the cellular redox status and is hijacked in malignantly transformed cells. CRITICAL ISSUES Several compounds affect the redox status of hexokinases in vivo. These include the dehydroascorbic acid (oxidized form of vitamin C), pyrrolidinium porrolidine-1-carbodithioate (contraceptive), peroxynitrite (product of ethanol metabolism), alloxan (a glucose analog), and isobenzothiazolinone ebselen. However, very limited information is available regarding which amino acid residues in hexokinases are affected by redox signaling. Except in cases of monogenic diabetes, direct evidence is absent for disease phenotypes that are associated with variations within motifs that are susceptible to redox signaling. FUTURE DIRECTIONS Further studies should address the propensity of hexokinases and their disease-associated variants to participate in redox regulation. Robust and straightforward proteomic methods are needed to understand the context and consequences of hexokinase-mediated redox regulation in health and disease.
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Affiliation(s)
- Petr Heneberg
- Third Faculty of Medicine, Charles University , Prague, Czech Republic
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14
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Abstract
Carbohydrate kinases activate a wide variety of monosaccharides by adding a phosphate group, usually from ATP. This modification is fundamental to saccharide utilization, and it is likely a very ancient reaction. Modern organisms contain carbohydrate kinases from at least five main protein families. These range from the highly specialized inositol kinases, to the ribokinases and galactokinases, which belong to families that phosphorylate a wide range of substrates. The carbohydrate kinases utilize a common strategy to drive the reaction between the sugar hydroxyl and the donor phosphate. Each sugar is held in position by a network of hydrogen bonds to the non-reactive hydroxyls (and other functional groups). The reactive hydroxyl is deprotonated, usually by an aspartic acid side chain acting as a catalytic base. The deprotonated hydroxyl then attacks the donor phosphate. The resulting pentacoordinate transition state is stabilized by an adjacent divalent cation, and sometimes by a positively charged protein side chain or the presence of an anion hole. Many carbohydrate kinases are allosterically regulated using a wide variety of strategies, due to their roles at critical control points in carbohydrate metabolism. The evolution of a similar mechanism in several folds highlights the elegance and simplicity of the catalytic scheme.
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15
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Ren X, Zou L, Lu J, Holmgren A. Selenocysteine in mammalian thioredoxin reductase and application of ebselen as a therapeutic. Free Radic Biol Med 2018; 127:238-247. [PMID: 29807162 DOI: 10.1016/j.freeradbiomed.2018.05.081] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/27/2018] [Accepted: 05/23/2018] [Indexed: 12/29/2022]
Abstract
Thioredoxin system is a ubiquitous disulfide reductase system evolutionarily conserved through all living organisms. It contains thioredoxin (Trx), thioredoxin reductase (TrxR) and NADPH. TrxR can use NADPH to reduce Trx which passes the reducing equivalent to its downstream substrates involved in various biomedical events, such as ribonucleotide reductase for deoxyribonucleotide and DNA synthesis, or peroxiredoxins for counteracting oxidative stress. Obviously, TrxR stays in the center of the system to maintain the electron flow. Mammalian TrxR contains a selenocysteine (Sec) in its active site, which is not present in the low molecular weight prokaryotic TrxRs. Due to the special property of Sec, mammalian TrxR employs a different catalytic mechanism from prokaryotic TrxRs and has a broader substrate-spectrum. On the other hand, Sec is easily targeted by electrophilic compounds which inhibits the TrxR activity and may turn TrxR into an NADPH oxidase. Ebselen, a synthetic seleno-compound containing selenazol, has been tested in several clinical studies. In mammalian cells, ebselen works as a GSH peroxidase mimic and mainly as a peroxiredoxin mimic via Trx and TrxR to scavenge hydrogen peroxide and peroxynitrite. In prokaryotic cells, ebselen is an inhibitor of TrxR and leads to elevation of reactive oxygen species (ROS). Recent studies have made use of the difference and developed ebselen as a potential antibiotic, especially in combination with silver which enables ebselen to kill multi-drug resistant Gram-negative bacteria. Collectively, Sec is important for the biological functions of mammalian TrxR and distinguishes it from prokaryotic TrxRs, therefore it is a promising drug target.
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Affiliation(s)
- Xiaoyuan Ren
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Lili Zou
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden; Translational Neuroscience & Neural Regeneration and Repair Institute/Institute of Cell Therapy, The First Hospital of Yichang, Three Gorges University, 443000 Yichang, China
| | - Jun Lu
- School of Pharmaceutical Sciences, Southwest University, 400715 Chongqing, China
| | - Arne Holmgren
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
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16
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Flaherty DP, Harris MT, Schroeder CE, Khan H, Kahney EW, Hackler AL, Patrick SL, Weiner WS, Aubé J, Sharlow ER, Morris JC, Golden JE. Optimization and Evaluation of Antiparasitic Benzamidobenzoic Acids as Inhibitors of Kinetoplastid Hexokinase 1. ChemMedChem 2017; 12:1994-2005. [PMID: 29105342 PMCID: PMC5808564 DOI: 10.1002/cmdc.201700592] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 10/26/2017] [Indexed: 11/05/2022]
Abstract
Kinetoplastid-based infections are neglected diseases that represent a significant human health issue. Chemotherapeutic options are limited due to toxicity, parasite susceptibility, and poor patient compliance. In response, we studied a molecular-target-directed approach involving intervention of hexokinase activity-a pivotal enzyme in parasite metabolism. A benzamidobenzoic acid hit with modest biochemical inhibition of Trypanosoma brucei hexokinase 1 (TbHK1, IC50 =9.1 μm), low mammalian cytotoxicity (IMR90 cells, EC50 >25 μm), and no appreciable activity on whole bloodstream-form (BSF) parasites was optimized to afford a probe with improved TbHK1 potency and, significantly, efficacy against whole BSF parasites (TbHK1, IC50 =0.28 μm; BSF, ED50 =1.9 μm). Compounds in this series also inhibited the hexokinase enzyme from Leishmania major (LmHK1), albeit with less potency than toward TbHK1, suggesting that inhibition of the glycolytic pathway may be a promising opportunity to target multiple disease-causing trypanosomatid protozoa.
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Affiliation(s)
- Daniel P Flaherty
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
- Present Address: Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, IN, 47907, USA
| | - Michael T Harris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
- Present Address: Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Chad E Schroeder
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
| | - Haaris Khan
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
| | - Elizabeth W Kahney
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
- Present Address: Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Amber L Hackler
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
| | - Stephen L Patrick
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
| | - Warren S Weiner
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
| | - Jeffrey Aubé
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
- Present Address: School of Pharmacy, University of North Carolina, 3012 Marsico Hall, 125 Mason Farm Road, Chapel Hill, NC, 27599, USA
| | - Elizabeth R Sharlow
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - James C Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
| | - Jennifer E Golden
- University of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS, 66049, USA
- Present Address: School of Pharmacy, Department of Pharmaceutical Sciences, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI, 53705, USA
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17
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Gordhan HM, Milanes JE, Qiu Y, Golden JE, Christensen KA, Morris JC, Whitehead DC. A targeted delivery strategy for the development of potent trypanocides. Chem Commun (Camb) 2017; 53:8735-8738. [PMID: 28726862 PMCID: PMC5576345 DOI: 10.1039/c7cc03378h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new drug delivery strategy was investigated for the development of potent anti-parasitic compounds against Trypanosoma brucei, the causative agent of African sleeping sickness. Thus, potent in vitro hexokinase inhibitors were rendered cytotoxic by appending a tripeptide peroxosomal targeting sequence that facilitated delivery of the molecular cargo to the appropriate organelle in the parasite.
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Affiliation(s)
| | - Jillian E Milanes
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA.
| | - Yijian Qiu
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA.
| | - Jennifer E Golden
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin, Madison, WI, USA
| | | | - James C Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA.
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18
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Hackler A, Patrick SL, Kahney EW, Flaherty DP, Sharlow ER, Morris JC, Golden JE. Antiparasitic lethality of sulfonamidebenzamides in kinetoplastids. Bioorg Med Chem Lett 2017; 27:755-758. [PMID: 28119024 DOI: 10.1016/j.bmcl.2017.01.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 11/26/2022]
Abstract
A sulfonamidebenzamide series was assessed for anti-kinetoplastid parasite activity based on structural similarity to the antiparasitic drug, nifurtimox. Through structure-activity optimization, derivatives with limited mammalian cell toxicity and increased potency toward African trypanosomes and Leishmania promastigotes were developed. Compound 22 had the best potency against the trypanosome (EC50=0.010μM) while several compounds showed ∼10-fold less potency against Leishmania promastigotes without impacting mammalian cells (EC50>25μM). While the chemotype originated from an unrelated optimization program aimed at selectively activating an apoptotic pathway in mammalian cancer cells, our preliminary results suggest that a distinct mechanism of action from that observed in mammalian cells is responsible for the promising activity observed in parasites.
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Affiliation(s)
- Amber Hackler
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
| | - Stephen L Patrick
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
| | - Elizabeth W Kahney
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
| | - Daniel P Flaherty
- KU Specialized Chemistry Center, University of Kansas, Lawrence, KS 66047, USA
| | - Elizabeth R Sharlow
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA; Fiske Drug Discovery Laboratory, University of Virginia, Charlottesville, VA 22908, USA
| | - James C Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
| | - Jennifer E Golden
- KU Specialized Chemistry Center, University of Kansas, Lawrence, KS 66047, USA.
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19
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Gordhan HM, Patrick SL, Swasy MI, Hackler AL, Anayee M, Golden JE, Morris JC, Whitehead DC. Evaluation of substituted ebselen derivatives as potential trypanocidal agents. Bioorg Med Chem Lett 2016; 27:537-541. [PMID: 28043795 DOI: 10.1016/j.bmcl.2016.12.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 10/20/2022]
Abstract
Human African trypanosomiasis is a disease of sub-Saharan Africa, where millions are at risk for the illness. The disease, commonly referred to as African sleeping sickness, is caused by an infection by the eukaryotic pathogen, Trypanosoma brucei. Previously, a target-based high throughput screen revealed ebselen (EbSe), and its sulfur analog, EbS, to be potent in vitro inhibitors of the T. brucei hexokinase 1 (TbHK1). These molecules also exhibited potent trypanocidal activity in vivo. In this manuscript, we synthesized a series of sixteen EbSe and EbS derivatives bearing electron-withdrawing carboxylic acid and methyl ester functional groups, and evaluated the influence of these substituents on the biological efficacy of the parent scaffold. With the exception of one methyl ester derivative, these modifications ablated or blunted the potent TbHK1 inhibition of the parent scaffold. Nonetheless, a few of the methyl ester derivatives still exhibited trypanocidal effects with single-digit micromolar or high nanomolar EC50 values.
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Affiliation(s)
- Heeren M Gordhan
- Department of Chemistry, 467 Hunter Laboratories, Clemson University, Clemson, SC 29634, USA
| | - Stephen L Patrick
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, 249 Life Sciences Building, Clemson University, Clemson, SC 29634, USA
| | - Maria I Swasy
- Department of Chemistry, 467 Hunter Laboratories, Clemson University, Clemson, SC 29634, USA
| | - Amber L Hackler
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, 249 Life Sciences Building, Clemson University, Clemson, SC 29634, USA
| | - Mark Anayee
- Department of Chemistry, 467 Hunter Laboratories, Clemson University, Clemson, SC 29634, USA
| | - Jennifer E Golden
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin, 777 Highland Ave., Madison, WI 53705-2222, USA
| | - James C Morris
- Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, 249 Life Sciences Building, Clemson University, Clemson, SC 29634, USA.
| | - Daniel C Whitehead
- Department of Chemistry, 467 Hunter Laboratories, Clemson University, Clemson, SC 29634, USA.
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20
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Identification of Novel Plasmodium falciparum Hexokinase Inhibitors with Antiparasitic Activity. Antimicrob Agents Chemother 2016; 60:6023-33. [PMID: 27458230 DOI: 10.1128/aac.00914-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/19/2016] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum, the deadliest species of malaria parasites, is dependent on glycolysis for the generation of ATP during the pathogenic red blood cell stage. Hexokinase (HK) catalyzes the first step in glycolysis, transferring the γ-phosphoryl group of ATP to glucose to yield glucose-6-phosphate. Here, we describe the validation of a high-throughput assay for screening small-molecule collections to identify inhibitors of the P. falciparum HK (PfHK). The assay, which employed an ADP-Glo reporter system in a 1,536-well-plate format, was robust with a signal-to-background ratio of 3.4 ± 1.2, a coefficient of variation of 6.8% ± 2.9%, and a Z'-factor of 0.75 ± 0.08. Using this assay, we screened 57,654 molecules from multiple small-molecule collections. Confirmed hits were resolved into four clusters on the basis of structural relatedness. Multiple singleton hits were also identified. The most potent inhibitors had 50% inhibitory concentrations as low as ∼1 μM, and several were found to have low-micromolar 50% effective concentrations against asexual intraerythrocytic-stage P. falciparum parasites. These molecules additionally demonstrated limited toxicity against a panel of mammalian cells. The identification of PfHK inhibitors with antiparasitic activity using this validated screening assay is encouraging, as it justifies additional HTS campaigns with more structurally amenable libraries for the identification of potential leads for future therapeutic development.
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21
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D'Antonio EL, Deinema MS, Kearns SP, Frey TA, Tanghe S, Perry K, Roy TA, Gracz HS, Rodriguez A, D'Antonio J. Structure-based approach to the identification of a novel group of selective glucosamine analogue inhibitors of Trypanosoma cruzi glucokinase. Mol Biochem Parasitol 2016; 204:64-76. [PMID: 26778112 DOI: 10.1016/j.molbiopara.2015.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 12/10/2015] [Accepted: 12/16/2015] [Indexed: 01/29/2023]
Abstract
Glucokinase and hexokinase from pathogenic protozoa Trypanosoma cruzi are potential drug targets for antiparasitic chemotherapy of Chagas' disease. These glucose kinases phosphorylate d-glucose with co-substrate ATP and yield glucose 6-phosphate and are involved in essential metabolic pathways, such as glycolysis and the pentose phosphate pathway. An inhibitor class was conceived that is selective for T. cruzi glucokinase (TcGlcK) using structure-based drug design involving glucosamine having a linker from the C2 amino that terminates with a hydrophobic group either being phenyl, p-hydroxyphenyl, or dioxobenzo[b]thiophenyl groups. The synthesis and characterization for two of the four compounds are presented while the other two compounds were commercially available. Four high-resolution X-ray crystal structures of TcGlcK inhibitor complexes are reported along with enzyme inhibition constants (Ki) for TcGlcK and Homo sapiens hexokinase IV (HsHxKIV). These glucosamine analogue inhibitors include three strongly selective TcGlcK inhibitors and a fourth inhibitor, benzoyl glucosamine (BENZ-GlcN), which is a similar variant exhibiting a shorter linker. Carboxybenzyl glucosamine (CBZ-GlcN) was found to be the strongest glucokinase inhibitor known to date, having a Ki of 0.71±0.05μM. Also reported are two biologically active inhibitors against in vitro T. cruzi culture that were BENZ-GlcN and CBZ-GlcN, with intracellular amastigote growth inhibition IC50 values of 16.08±0.16μM and 48.73±0.69μM, respectively. These compounds revealed little to no toxicity against mammalian NIH-3T3 fibroblasts and provide a key starting point for further drug development with this class of compound.
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Affiliation(s)
- Edward L D'Antonio
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA.
| | - Mason S Deinema
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| | - Sean P Kearns
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| | - Tyler A Frey
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| | - Scott Tanghe
- Department of Microbiology, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
| | - Kay Perry
- NE-CAT, Department of Chemistry and Chemical Biology, Cornell University, Building 436E, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA
| | - Timothy A Roy
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
| | - Hanna S Gracz
- Department of Molecular and Structural Biochemistry, North Carolina State University, 128 Polk Hall, Raleigh, North Carolina 27695, USA
| | - Ana Rodriguez
- Department of Microbiology, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
| | - Jennifer D'Antonio
- Department of Natural Sciences, University of South Carolina Beaufort, 1 University Boulevard, Bluffton, South Carolina 29909, USA
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22
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Eudes A, Teixeira Benites V, Wang G, Baidoo EEK, Lee TS, Keasling JD, Loqué D. Precursor-Directed Combinatorial Biosynthesis of Cinnamoyl, Dihydrocinnamoyl, and Benzoyl Anthranilates in Saccharomyces cerevisiae. PLoS One 2015; 10:e0138972. [PMID: 26430899 PMCID: PMC4591981 DOI: 10.1371/journal.pone.0138972] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/07/2015] [Indexed: 01/23/2023] Open
Abstract
Biological synthesis of pharmaceuticals and biochemicals offers an environmentally friendly alternative to conventional chemical synthesis. These alternative methods require the design of metabolic pathways and the identification of enzymes exhibiting adequate activities. Cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates are natural metabolites which possess beneficial activities for human health, and the search is expanding for novel derivatives that might have enhanced biological activity. For example, biosynthesis in Dianthus caryophyllus is catalyzed by hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/ benzoyltransferase (HCBT), which couples hydroxycinnamoyl-CoAs and benzoyl-CoAs to anthranilate. We recently demonstrated the potential of using yeast (Saccharomyces cerevisiae) for the biological production of a few cinnamoyl anthranilates by heterologous co-expression of 4-coumaroyl:CoA ligase from Arabidopsis thaliana (4CL5) and HCBT. Here we report that, by exploiting the substrate flexibility of both 4CL5 and HCBT, we achieved rapid biosynthesis of more than 160 cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates in yeast upon feeding with both natural and non-natural cinnamates, dihydrocinnamates, benzoates, and anthranilates. Our results demonstrate the use of enzyme promiscuity in biological synthesis to achieve high chemical diversity within a defined class of molecules. This work also points to the potential for the combinatorial biosynthesis of diverse and valuable cinnamoylated, dihydrocinnamoylated, and benzoylated products by using the versatile biological enzyme 4CL5 along with characterized cinnamoyl-CoA- and benzoyl-CoA-utilizing transferases.
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Affiliation(s)
- Aymerick Eudes
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4 Floor, Emeryville, California, 94608, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States of America
| | - Veronica Teixeira Benites
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4 Floor, Emeryville, California, 94608, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States of America
- Graduate Program, San Francisco State University, San Francisco, California, 94132, United States of America
| | - George Wang
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4 Floor, Emeryville, California, 94608, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States of America
| | - Edward E. K. Baidoo
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4 Floor, Emeryville, California, 94608, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States of America
| | - Taek Soon Lee
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4 Floor, Emeryville, California, 94608, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States of America
| | - Jay D. Keasling
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4 Floor, Emeryville, California, 94608, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States of America
- Department of Bioengineering & Department of Chemical & Biomolecular Engineering, University of California, Berkeley, California, 94720, United States of America
| | - Dominique Loqué
- Joint BioEnergy Institute, Emery Station East, 5885 Hollis St, 4 Floor, Emeryville, California, 94608, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, United States of America
- * E-mail:
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23
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Hol WGJ. Three-dimensional structures in the design of therapeutics targeting parasitic protozoa: reflections on the past, present and future. Acta Crystallogr F Struct Biol Commun 2015; 71:485-99. [PMID: 25945701 PMCID: PMC4427157 DOI: 10.1107/s2053230x15004987] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 03/11/2015] [Indexed: 11/10/2022] Open
Abstract
Parasitic protozoa cause a range of diseases which threaten billions of human beings. They are responsible for tremendous mortality and morbidity in the least-developed areas of the world. Presented here is an overview of the evolution over the last three to four decades of structure-guided design of inhibitors, leads and drug candidates aiming at targets from parasitic protozoa. Target selection is a crucial and multi-faceted aspect of structure-guided drug design. The major impact of advances in molecular biology, genome sequencing and high-throughput screening is touched upon. The most advanced crystallographic techniques, including XFEL, have already been applied to structure determinations of drug targets from parasitic protozoa. Even cryo-electron microscopy is contributing to our understanding of the mode of binding of inhibitors to parasite ribosomes. A number of projects have been selected to illustrate how structural information has assisted in arriving at promising compounds that are currently being evaluated by pharmacological, pharmacodynamic and safety tests to assess their suitability as pharmaceutical agents. Structure-guided approaches are also applied to incorporate properties into compounds such that they are less likely to become the victim of resistance mechanisms. A great increase in the number of novel antiparasitic compounds will be needed in the future. These should then be combined into various multi-compound therapeutics to circumvent the diverse resistance mechanisms that render single-compound, or even multi-compound, drugs ineffective. The future should also see (i) an increase in the number of projects with a tight integration of structural biology, medicinal chemistry, parasitology and pharmaceutical sciences; (ii) the education of more `medicinal structural biologists' who are familiar with the properties that compounds need to have for a high probability of success in the later steps of the drug-development process; and (iii) the expansion of drug-development capabilities in middle- and low-income countries.
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Affiliation(s)
- Wim G. J. Hol
- Department of Biochemistry and Biomolecular Structure Center, University of Washington, Seattle, WA 98195, USA
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24
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In silico search of energy metabolism inhibitors for alternative leishmaniasis treatments. BIOMED RESEARCH INTERNATIONAL 2015; 2015:965725. [PMID: 25918726 PMCID: PMC4396002 DOI: 10.1155/2015/965725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/08/2014] [Accepted: 09/14/2014] [Indexed: 12/12/2022]
Abstract
Leishmaniasis is a complex disease that affects mammals and is caused by approximately 20 distinct protozoa from the genus Leishmania. Leishmaniasis is an endemic disease that exerts a large socioeconomic impact on poor and developing countries. The current treatment for leishmaniasis is complex, expensive, and poorly efficacious. Thus, there is an urgent need to develop more selective, less expensive new drugs. The energy metabolism pathways of Leishmania include several interesting targets for specific inhibitors. In the present study, we sought to establish which energy metabolism enzymes in Leishmania could be targets for inhibitors that have already been approved for the treatment of other diseases. We were able to identify 94 genes and 93 Leishmania energy metabolism targets. Using each gene's designation as a search criterion in the TriTrypDB database, we located the predicted peptide sequences, which in turn were used to interrogate the DrugBank, Therapeutic Target Database (TTD), and PubChem databases. We identified 44 putative targets of which 11 are predicted to be amenable to inhibition by drugs which have already been approved for use in humans for 11 of these targets. We propose that these drugs should be experimentally tested and potentially used in the treatment of leishmaniasis.
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25
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Advanced enzymology, expression profile and immune response of Clonorchis sinensis hexokinase show its application potential for prevention and control of clonorchiasis. PLoS Negl Trop Dis 2015; 9:e0003641. [PMID: 25799453 PMCID: PMC4370448 DOI: 10.1371/journal.pntd.0003641] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 02/24/2015] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Approximately 35 million people are infected with Clonorchis sinensis (C. sinensis) globally, of whom 15 million are in China. Glycolytic enzymes are recognized as crucial molecules for trematode survival and have been targeted for vaccine and drug development. Hexokinase of C. sinensis (CsHK), as the first key regulatory enzyme of the glycolytic pathway, was investigated in the current study. PRINCIPAL FINDINGS There were differences in spatial structure and affinities for hexoses and phosphate donors between CsHK and HKs from humans or rats, the definitive hosts of C. sinensis. Effectors (AMP, PEP, and citrate) and a small molecular inhibitor regulated the enzymatic activity of rCsHK, and various allosteric systems were detected. CsHK was distributed in the worm extensively as well as in liver tissue and serum from C. sinensis infected rats. Furthermore, high-level specific IgG1 and IgG2a were induced in rats by immunization with rCsHK. The enzymatic activity of CsHK was suppressed by the antibody in vitro. Additionally, the survival of C. sinensis was inhibited by the antibody in vivo and in vitro. CONCLUSIONS/SIGNIFICANCE Due to differences in putative spatial structure and enzymology between CsHK and HK from the host, its extensive distribution in adult worms, and its expression profile as a component of excretory/secretory products, together with its good immunogenicity and immunoreactivity, as a key glycolytic enzyme, CsHK shows potential as a vaccine and as a promising drug target for Clonorchiasis.
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26
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Merritt C, Silva L, Tanner AL, Stuart K, Pollastri MP. Kinases as druggable targets in trypanosomatid protozoan parasites. Chem Rev 2014; 114:11280-304. [PMID: 26443079 PMCID: PMC4254031 DOI: 10.1021/cr500197d] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Indexed: 12/21/2022]
Affiliation(s)
- Christopher Merritt
- Seattle
Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, Washington 98109-5219, United States
| | - Lisseth
E. Silva
- Department
of Chemistry & Chemical Biology, Northeastern
University, 417 Egan
Research Center, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Angela L. Tanner
- Department
of Chemistry & Chemical Biology, Northeastern
University, 417 Egan
Research Center, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Kenneth Stuart
- Seattle
Biomedical Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, Washington 98109-5219, United States
| | - Michael P. Pollastri
- Department
of Chemistry & Chemical Biology, Northeastern
University, 417 Egan
Research Center, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
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27
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Sequence analysis and molecular characterization of Clonorchis sinensis hexokinase, an unusual trimeric 50-kDa glucose-6-phosphate-sensitive allosteric enzyme. PLoS One 2014; 9:e107940. [PMID: 25232723 PMCID: PMC4169440 DOI: 10.1371/journal.pone.0107940] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/15/2014] [Indexed: 12/17/2022] Open
Abstract
Clonorchiasis, which is induced by the infection of Clonorchis sinensis (C. sinensis), is highly associated with cholangiocarcinoma. Because the available examination, treatment and interrupting transmission provide limited opportunities to prevent infection, it is urgent to develop integrated strategies to prevent and control clonorchiasis. Glycolytic enzymes are crucial molecules for trematode survival and have been targeted for drug development. Hexokinase of C. sinensis (CsHK), the first key regulatory enzyme of the glycolytic pathway, was characterized in this study. The calculated molecular mass (Mr) of CsHK was 50.0 kDa. The obtained recombinant CsHK (rCsHK) was a homotrimer with an Mr of approximately 164 kDa, as determined using native PAGE and gel filtration. The highest activity was obtained with 50 mM glycine-NaOH at pH 10 and 100 mM Tris-HCl at pH 8.5 and 10. The kinetics of rCsHK has a moderate thermal stability. Compared to that of the corresponding negative control, the enzymatic activity was significantly inhibited by praziquantel (PZQ) and anti-rCsHK serum. rCsHK was homotropically and allosterically activated by its substrates, including glucose, mannose, fructose, and ATP. ADP exhibited mixed allosteric effect on rCsHK with respect to ATP, while inorganic pyrophosphate (PPi) displayed net allosteric activation with various allosteric systems. Fructose behaved as a dose-dependent V activator with the substrate glucose. Glucose-6-phosphate (G6P) displayed net allosteric inhibition on rCsHK with respect to ATP or glucose with various allosteric systems in a dose-independent manner. There were differences in both mRNA and protein levels of CsHK among the life stages of adult worm, metacercaria, excysted metacercaria and egg of C. sinensis, suggesting different energy requirements during different development stages. Our study furthers the understanding of the biological functions of CsHK and supports the need to screen for small molecule inhibitors of CsHK to interfere with glycolysis in C. sinensis.
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28
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Li J, Yuan J, Cheng KCC, Inglese J, Su XZ. Chemical genomics for studying parasite gene function and interaction. Trends Parasitol 2013; 29:603-11. [PMID: 24215777 DOI: 10.1016/j.pt.2013.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/08/2013] [Accepted: 10/08/2013] [Indexed: 12/20/2022]
Abstract
With the development of new technologies in genome sequencing, gene expression profiling, genotyping, and high-throughput screening of chemical compound libraries, small molecules are playing increasingly important roles in studying gene expression regulation, gene-gene interaction, and gene function. Here we briefly review and discuss some recent advancements in drug target identification and phenotype characterization using combinations of high-throughput screening of small-molecule libraries and various genome-wide methods such as whole-genome sequencing, genome-wide association studies (GWAS), and genome-wide expression analysis. These approaches can be used to search for new drugs against parasite infections, to identify drug targets or drug resistance genes, and to infer gene function.
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Affiliation(s)
- Jian Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, P.R. China
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29
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Joice AC, Harris MT, Kahney EW, Dodson HC, Maselli AG, Whitehead DC, Morris JC. Exploring the mode of action of ebselen in Trypanosoma brucei hexokinase inhibition. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2013; 3:154-60. [PMID: 24533305 PMCID: PMC3862409 DOI: 10.1016/j.ijpddr.2013.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Trypanosoma brucei hexokinase 1 is irreversibly inhibited by ebselen. Mutation of Cys residues did not change hexamer abundance. Active variants bearing Cys mutations were inhibited by ebselen. ESI–MS/MS indicated that the essential Cys327 was oxidized by ebselen.
Glycolysis is essential to Trypanosoma brucei, the causative agent of African sleeping sickness, suggesting enzymes in the pathway could be targets for drug development. Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one, EbSe) was identified in a screen as a potent inhibitor of T. brucei hexokinase 1 (TbHK1), the first enzyme in the pathway. EbSe has a history of promiscuity as an enzyme inhibitor, inactivating proteins through seleno-sulfide conjugation with Cys residues. Indeed, dilution of TbHK1 and inhibitor following incubation did not temper inhibition suggesting conjugate formation. Using mass spectrometry to analyze EbSe-based modifications revealed that two Cys residues (C327 and C369) were oxidized after treatment. Site-directed mutagenesis of C327 led to enzyme inactivation indicating that C327 was essential for catalysis. C369 was not essential, suggesting that EbSe inhibition of TbHK1 was the consequence of modification of C327 via thiol oxidation. Additionally, neither EbSe treatment nor mutation of the nine TbHK1 Cys residues appreciably altered enzyme quaternary structure.
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Key Words
- BSF, bloodstream form
- EbS, 2-phenyl-12-benzisothiazol-3(2H)-one
- EbSe, ebselen (2-phenyl-12-benzisoselenazol-3(2H)-one)
- Ebselen
- G6-P, glucose-6-phosphate
- G6PDH, glucose-6-phosphate dehydrogenase
- GK, glycerol kinase
- Gly3P, glycerol-3-phosphate
- HK, hexokinase
- Hexokinase
- Inhibitors
- PF, procyclic form
- TbHK, T. brucei hexokinase
- Trypanosoma brucei
- rTbHK1, recombinant Trypanosoma brucei hexokinase 1
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Affiliation(s)
- April C Joice
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Michael T Harris
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Elizabeth W Kahney
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Heidi C Dodson
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
| | - Andrew G Maselli
- Department of Biological Sciences, Chicago State University, Chicago, IL 60628, United States
| | - Daniel C Whitehead
- Department of Chemistry, Clemson University, Clemson, SC 29634, United States
| | - James C Morris
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, United States
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30
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Lu J, Vodnala SK, Gustavsson AL, Gustafsson TN, Sjöberg B, Johansson HA, Kumar S, Tjernberg A, Engman L, Rottenberg ME, Holmgren A. Ebsulfur is a benzisothiazolone cytocidal inhibitor targeting the trypanothione reductase of Trypanosoma brucei. J Biol Chem 2013; 288:27456-27468. [PMID: 23900839 DOI: 10.1074/jbc.m113.495101] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Trypanosoma brucei is the causing agent of African trypanosomiasis. These parasites possess a unique thiol redox system required for DNA synthesis and defense against oxidative stress. It includes trypanothione and trypanothione reductase (TryR) instead of the thioredoxin and glutaredoxin systems of mammalian hosts. Here, we show that the benzisothiazolone compound ebsulfur (EbS), a sulfur analogue of ebselen, is a potent inhibitor of T. brucei growth with a favorable selectivity index over mammalian cells. EbS inhibited the TryR activity and decreased non-protein thiol levels in cultured parasites. The inhibition of TryR by EbS was irreversible and NADPH-dependent. EbS formed a complex with TryR and caused oxidation and inactivation of the enzyme. EbS was more toxic for T. brucei than for Trypanosoma cruzi, probably due to lower levels of TryR and trypanothione in T. brucei. Furthermore, inhibition of TryR produced high intracellular reactive oxygen species. Hydrogen peroxide, known to be constitutively high in T. brucei, enhanced the EbS inhibition of TryR. The elevation of reactive oxygen species production in parasites caused by EbS induced a programmed cell death. Soluble EbS analogues were synthesized and cured T. brucei brucei infection in mice when used together with nifurtimox. Altogether, EbS and EbS analogues disrupt the trypanothione system, hampering the defense against oxidative stress. Thus, EbS is a promising lead for development of drugs against African trypanosomiasis.
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Affiliation(s)
- Jun Lu
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics
| | | | - Anna-Lena Gustavsson
- Chemical Biology Consortium Sweden, Science for Life Laboratory, Division of Translational Medicine, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Tomas N Gustafsson
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics
| | - Birger Sjöberg
- Chemical Biology Consortium Sweden, Science for Life Laboratory, Division of Translational Medicine, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Henrik A Johansson
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics; Department of Chemistry-BMC, Uppsala University, SE-751 23 Uppsala, Sweden
| | | | | | - Lars Engman
- Department of Chemistry-BMC, Uppsala University, SE-751 23 Uppsala, Sweden
| | | | - Arne Holmgren
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics.
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31
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Interrogating a hexokinase-selected small-molecule library for inhibitors of Plasmodium falciparum hexokinase. Antimicrob Agents Chemother 2013; 57:3731-7. [PMID: 23716053 DOI: 10.1128/aac.00662-13] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Parasites in the genus Plasmodium cause disease throughout the tropic and subtropical regions of the world. P. falciparum, one of the deadliest species of the parasite, relies on glycolysis for the generation of ATP while it inhabits the mammalian red blood cell. The first step in glycolysis is catalyzed by hexokinase (HK). While the 55.3-kDa P. falciparum HK (PfHK) shares several biochemical characteristics with mammalian HKs, including being inhibited by its products, it has limited amino acid identity (~26%) to the human HKs, suggesting that enzyme-specific therapeutics could be generated. To that end, interrogation of a selected small-molecule library of HK inhibitors has identified a class of PfHK inhibitors, isobenzothiazolinones, some of which have 50% inhibitory concentrations (IC50s) of <1 μM. Inhibition was reversible by dilution but not by treatment with a reducing agent, suggesting that the basis for enzyme inactivation was not covalent association with the inhibitor. Lastly, six of these compounds and the related molecule ebselen inhibited P. falciparum growth in vitro (50% effective concentration [EC50] of ≥ 0.6 and <6.8 μM). These findings suggest that the chemotypes identified here could represent leads for future development of therapeutics against P. falciparum.
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32
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Rocha MN, Corrêa CM, Melo MN, Beverley SM, Martins-Filho OA, Madureira AP, Soares RP. An alternative in vitro drug screening test using Leishmania amazonensis transfected with red fluorescent protein. Diagn Microbiol Infect Dis 2013; 75:282-91. [PMID: 23312610 PMCID: PMC3733281 DOI: 10.1016/j.diagmicrobio.2012.11.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/25/2012] [Accepted: 11/16/2012] [Indexed: 11/30/2022]
Abstract
Fluorescent and colorimetric reporter genes are valuable tools for drug screening models, since microscopy is labor intensive and subject to observer variation. In this work, we propose a fluorimetric method for drug screening using red fluorescent parasites. Fluorescent Leishmania amazonensis were developed after transfection with integration plasmids containing either red (RFP) or green fluorescent protein (GFP) genes. After transfection, wild-type (LaWT) and transfected (LaGFP and LaRFP) parasites were subjected to flow cytometry, macrophage infection, and tests of susceptibility to current antileishmanial agents and propranolol derivatives previously shown to be active against Trypanosoma cruzi. Flow cytometry analysis discriminated LaWT from LaRFP and LaGFP parasites, without affecting cell size or granulosity. With microscopy, transfection with antibiotic resistant genes was not shown to affect macrophage infectivity and susceptibility to amphotericin B and propranolol derivatives. Retention of fluorescence remained in the intracellular amastigotes in both LaGFP and LaRFP transfectants. However, detection of intracellular RFP parasites was only achieved in the fluorimeter. Murine BALB/c macrophages were infected with LaRFP parasites, exposed to standard (meglumine antimoniate, amphotericin B, Miltefosine, and allopurinol) and tested molecules. Although it was possible to determine IC(50) values for 4 propranolol derivatives (1, 2b, 3, and 4b), all compounds were considered inactive. This study is the first to develop a fluorimetric drug screening test for L. amazonensis RFP. The fluorimetric test was comparable to microscopy with the advantage of being faster and not requiring manual counting.
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Affiliation(s)
- Marcele N. Rocha
- Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz/FIOCRUZ, 30190-002 Belo Horizonte, MG, Brazil
| | - Célia M. Corrêa
- Laboratório de Química Farmacêutica, DEFAR, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - Maria N. Melo
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Stephen M. Beverley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Ana Paula Madureira
- Departamento de Engenharia de Biossistemas (DEPEB), Universidade Federal de São João Del Rey, São João Del Rey, Minas Gerais, Brazil
| | - Rodrigo P. Soares
- Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz/FIOCRUZ, 30190-002 Belo Horizonte, MG, Brazil
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33
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Identification of compounds with anti-proliferative activity against Trypanosoma brucei brucei strain 427 by a whole cell viability based HTS campaign. PLoS Negl Trop Dis 2012; 6:e1896. [PMID: 23209849 PMCID: PMC3510080 DOI: 10.1371/journal.pntd.0001896] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 09/21/2012] [Indexed: 11/19/2022] Open
Abstract
Human African Trypanosomiasis (HAT) is caused by two trypanosome sub-species, Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Drugs available for the treatment of HAT have significant issues related to difficult administration regimes and limited efficacy across species and disease stages. Hence, there is considerable need to find new alternative and less toxic drugs. An approach to identify starting points for new drug candidates is high throughput screening (HTS) of large compound library collections. We describe the application of an Alamar Blue based, 384-well HTS assay to screen a library of 87,296 compounds against the related trypanosome subspecies, Trypanosoma brucei brucei bloodstream form lister 427. Primary hits identified against T.b. brucei were retested and the IC50 value compounds were estimated for T.b. brucei and a mammalian cell line HEK293, to determine a selectivity index for each compound. The screening campaign identified 205 compounds with greater than 10 times selectivity against T.b. brucei. Cluster analysis of these compounds, taking into account chemical and structural properties required for drug-like compounds, afforded a panel of eight compounds for further biological analysis. These compounds had IC50 values ranging from 0.22 µM to 4 µM with associated selectivity indices ranging from 19 to greater than 345. Further testing against T.b. rhodesiense led to the selection of 6 compounds from 5 new chemical classes with activity against the causative species of HAT, which can be considered potential candidates for HAT early drug discovery. Structure activity relationship (SAR) mining revealed components of those hit compound structures that may be important for biological activity. Four of these compounds have undergone further testing to 1) determine whether they are cidal or static in vitro at the minimum inhibitory concentration (MIC), and 2) estimate the time to kill. Human African Sleeping Sickness (HAT) is a disease caused by sub-species of Trypanosoma. The disease affects developing countries within Africa, mainly occurring in rural regions that lack resources to purchase drugs for treatment. Drugs that are currently available have significant side effects, and treatment regimes are lengthy and not always transferrable to the field. In consideration of these factors, new drugs are urgently needed for the treatment of HAT. To discover compounds suitable for drug discovery, cultured trypanosomes can be tested against libraries of compounds to identify candidates for further biological analysis. We have utilised a 384-well format, Alamar Blue viability assay to screen a large non-proprietary compound collection against Trypanosoma brucei brucei bloodstream form lister 427. The assay was shown to be reproducible, with reference compounds exhibiting activity in agreement with previously published results. Primary screening hits were retested against T.b. brucei and HEK293 mammalian cells in order to assess selectivity against the parasite. Selective hits were characterised by chemical analysis, taking into consideration drug-like properties amenable to further progression. Priority compounds were tested against a panel of protozoan parasites, including Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum. Five new compound classes were discovered that are amenable to progression in the drug discovery process for HAT.
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Translocation of solutes and proteins across the glycosomal membrane of trypanosomes; possibilities and limitations for targeting with trypanocidal drugs. Parasitology 2012; 140:1-20. [PMID: 22914253 DOI: 10.1017/s0031182012001278] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Glycosomes are specialized peroxisomes found in all kinetoplastid organisms. The organelles are unique in harbouring most enzymes of the glycolytic pathway. Matrix proteins, synthesized in the cytosol, cofactors and metabolites have to be transported across the membrane. Recent research on Trypanosoma brucei has provided insight into how these translocations across the membrane occur, although many details remain to be elucidated. Proteins are imported by a cascade of reactions performed by specialized proteins, called peroxins, in which a cytosolic receptor with bound matrix protein inserts itself in the membrane to deliver its cargo into the organelle and is subsequently retrieved from the glycosome to perform further rounds of import. Bulky solutes, such as cofactors and acyl-CoAs, seem to be translocated by specific transporter molecules, whereas smaller solutes such as glycolytic intermediates probably cross the membrane through pore-forming channels. The presence of such channels is in apparent contradiction with previous results that suggested a low permeability of the glycosomal membrane. We propose 3 possible, not mutually exclusive, solutions for this paradox. Glycosomal glycolytic enzymes have been validated as drug targets against trypanosomatid-borne diseases. We discuss the possible implications of the new data for the design of drugs to be delivered into glycosomes.
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Vigueira PA, Paul KS. Trypanosoma brucei: inhibition of acetyl-CoA carboxylase by haloxyfop. Exp Parasitol 2011; 130:159-65. [PMID: 22119241 DOI: 10.1016/j.exppara.2011.10.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 10/08/2011] [Accepted: 10/31/2011] [Indexed: 10/15/2022]
Abstract
Trypanosoma brucei, a eukaryotic pathogen that causes African sleeping sickness in humans and nagana in cattle, depends on the enzyme acetyl-CoA carboxylase (ACC) for full virulence in mice. ACC produces malonyl-CoA, the two carbon donor for fatty acid synthesis. We assessed the effect of haloxyfop, an aryloxyphenoxypropionate herbicide inhibitor of plastid ACCs in many plants as well as Toxoplasma gondii, on T. brucei ACC activity and growth in culture. Haloxyfop inhibited TbACC in cell lysate (EC(50) 67 μM), despite the presence of an amino acid motif typically associated with resistance. Haloxyfop also reduced growth of bloodstream and procyclic form parasites (EC(50) of 0.8 and 1.2 mM). However, the effect on growth was likely due to off-target effects because haloxyfop treatment had no effect on fatty acid elongation or incorporation into complex lipids in vivo.
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Affiliation(s)
- Patrick A Vigueira
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA.
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Diechtierow M, Krauth-Siegel RL. A tryparedoxin-dependent peroxidase protects African trypanosomes from membrane damage. Free Radic Biol Med 2011; 51:856-68. [PMID: 21640819 DOI: 10.1016/j.freeradbiomed.2011.05.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 05/11/2011] [Accepted: 05/11/2011] [Indexed: 01/18/2023]
Abstract
Hydroperoxide detoxification in African trypanosomes is achieved by 2-Cys-peroxiredoxin (TXNPx)- and non-selenium glutathione peroxidase (Px)-type enzymes which both obtain their reducing equivalents from the unique trypanothione/tryparedoxin system. Previous RNA interference approaches revealed that the cytosolic TXNPx and the Px-type enzymes are essential for Trypanosoma brucei. Because of partially overlapping in vitro substrate specificities and subcellular localisation the physiological function of the individual enzymes was not yet clear. As shown here, TXNPx and Px are expressed at comparable levels and in their active reduced state. Px-overexpressing parasites were less sensitive toward linoleic acid hydroperoxide but not hydrogen peroxide. Kinetic studies confirmed that Px-but not TXNPx-reduces lipophilic hydroperoxides including phospholipids with high efficiency. Most interestingly, the severe proliferation defect of Px-depleted bloodstream cells could be rescued by Trolox, but not by hydrophilic antioxidants, in the medium. This allowed us to knock-out the three Px genes individually and thus to distinguish their in vivo role. Deletion of the cytosolic Px I and II resulted in extremely fast membrane peroxidation followed by cell lysis. Cells lacking specifically the mitochondrial Px III showed a transient growth retardation and cardiolipin peroxidation but adapted within 24h to normal proliferation.
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Affiliation(s)
- Michael Diechtierow
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
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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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Coley AF, Dodson HC, Morris MT, Morris JC. Glycolysis in the african trypanosome: targeting enzymes and their subcellular compartments for therapeutic development. Mol Biol Int 2011; 2011:123702. [PMID: 22091393 PMCID: PMC3195984 DOI: 10.4061/2011/123702] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Accepted: 02/16/2011] [Indexed: 12/16/2022] Open
Abstract
Subspecies of the African trypanosome, Trypanosoma brucei, which cause human African trypanosomiasis, are transmitted by the tsetse fly, with transmission-essential lifecycle stages occurring in both the insect vector and human host. During infection of the human host, the parasite is limited to using glycolysis of host sugar for ATP production. This dependence on glucose breakdown presents a series of targets for potential therapeutic development, many of which have been explored and validated as therapeutic targets experimentally. These include enzymes directly involved in glucose metabolism (e.g., the trypanosome hexokinases), as well as cellular components required for development and maintenance of the essential subcellular compartments that house the major part of the pathway, the glycosomes.
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Affiliation(s)
- April F Coley
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
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Preissl S, Bick I, Obrdlik P, Diekert K, Gul S, Gribbon P. Development of an assay for Complex I/Complex III of the respiratory chain using solid supported membranes and its application in mitochondrial toxicity screening in drug discovery. Assay Drug Dev Technol 2010; 9:147-56. [PMID: 21133681 DOI: 10.1089/adt.2010.0320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Membrane-bound transporter proteins are involved in cell signal transduction and metabolism as well as influencing key pharmacological properties such as drug bioavailability. The functional activity of transporters that belong to the group of electrically active membrane proteins can be directly monitored using the solid-supported membrane-based SURFE(2)R™ technology (SURFace Electrogenic Event Reader; Scientific Devices Heidelberg GmbH, Heidelberg, Germany). The method makes use of membrane fragments or vesicles containing transport proteins adsorbed onto solid-supported membrane-covered electrodes and allows the direct measurement of their activity. This technology has been used to develop a robust screening compatible assay for Complex I/Complex III, key components of the respiratory chain in 96-well microtiter plates. The assay was screened against 1,000 compounds from the ComGenex Lead-like small molecule library to ascertain whether mitochondrial liabilities might be an underlying, although undesirable feature of typical commercial screening libraries. Some 105 hits (compounds exhibiting >50% inhibition of Complex I/Complex III activity at 10 μM) were identified and their activities were subsequently confirmed in duplicate, yielding a confirmation rate of 68%. Analysis of the confirmed hits also provided evidence of structure-activity relationships and two compounds from one structural class were further evaluated in dose-response experiments. This study provides evidence that profiling of compounds for potential mitochondrial liabilities, even at an early stage of drug discovery, may be a necessary additional quality filter that should be considered during the compound screening and profiling cascade.
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Dodson HC, Lyda TA, Chambers JW, Morris MT, Christensen KA, Morris JC. Quercetin, a fluorescent bioflavanoid, inhibits Trypanosoma brucei hexokinase 1. Exp Parasitol 2010; 127:423-8. [PMID: 20971104 DOI: 10.1016/j.exppara.2010.10.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 09/22/2010] [Accepted: 10/14/2010] [Indexed: 12/01/2022]
Abstract
Hexokinases from the African trypanosome, Trypanosoma brucei, are attractive targets for the development of anti-parasitic drugs, in part because the parasite utilizes glycolysis exclusively for ATP production during the mammalian infection. Here, we have demonstrated that the bioflavanoid quercetin (QCN), a known trypanocide, is a mixed inhibitor of Trypanosoma brucei hexokinase 1 (TbHK1) (IC(50) = 4.1 ± 0.8μM). Spectroscopic analysis of QCN binding to TbHK1, taking advantage of the intrinsically fluorescent single tryptophan (Trp177) in TbHK1, revealed that QCN quenches emission of Trp177, which is located near the hinge region of the enzyme. ATP similarly quenched Trp177 emission, while glucose had no impact on fluorescence. Supporting the possibility that QCN toxicity is a consequence of inhibition of the essential hexokinase, in live parasites QCN fluorescence localizes to glycosomes, the subcellular home of TbHK1. Additionally, RNAi-mediated silencing of TbHK1 expression expedited QCN induced death, while over-expressing TbHK1 protected trypanosomes from the compound. In summary, these observations support the suggestion that QCN toxicity is in part attributable to inhibition of the essential TbHK1.
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Affiliation(s)
- Heidi C Dodson
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
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Crowther GJ, Shanmugam D, Carmona SJ, Doyle MA, Hertz-Fowler C, Berriman M, Nwaka S, Ralph SA, Roos DS, Van Voorhis WC, Agüero F. Identification of attractive drug targets in neglected-disease pathogens using an in silico approach. PLoS Negl Trop Dis 2010; 4:e804. [PMID: 20808766 PMCID: PMC2927427 DOI: 10.1371/journal.pntd.0000804] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 07/27/2010] [Indexed: 12/02/2022] Open
Abstract
Background The increased sequencing of pathogen genomes and the subsequent availability of genome-scale functional datasets are expected to guide the experimental work necessary for target-based drug discovery. However, a major bottleneck in this has been the difficulty of capturing and integrating relevant information in an easily accessible format for identifying and prioritizing potential targets. The open-access resource TDRtargets.org facilitates drug target prioritization for major tropical disease pathogens such as the mycobacteria Mycobacterium leprae and Mycobacterium tuberculosis; the kinetoplastid protozoans Leishmania major, Trypanosoma brucei, and Trypanosoma cruzi; the apicomplexan protozoans Plasmodium falciparum, Plasmodium vivax, and Toxoplasma gondii; and the helminths Brugia malayi and Schistosoma mansoni. Methodology/Principal Findings Here we present strategies to prioritize pathogen proteins based on whether their properties meet criteria considered desirable in a drug target. These criteria are based upon both sequence-derived information (e.g., molecular mass) and functional data on expression, essentiality, phenotypes, metabolic pathways, assayability, and druggability. This approach also highlights the fact that data for many relevant criteria are lacking in less-studied pathogens (e.g., helminths), and we demonstrate how this can be partially overcome by mapping data from homologous genes in well-studied organisms. We also show how individual users can easily upload external datasets and integrate them with existing data in TDRtargets.org to generate highly customized ranked lists of potential targets. Conclusions/Significance Using the datasets and the tools available in TDRtargets.org, we have generated illustrative lists of potential drug targets in seven tropical disease pathogens. While these lists are broadly consistent with the research community's current interest in certain specific proteins, and suggest novel target candidates that may merit further study, the lists can easily be modified in a user-specific manner, either by adjusting the weights for chosen criteria or by changing the criteria that are included. In cell-based drug development, researchers attempt to create drugs that kill a pathogen without necessarily understanding the details of how the drugs work. In contrast, target-based drug development entails the search for compounds that act on a specific intracellular target—often a protein known or suspected to be required for survival of the pathogen. The latter approach to drug development has been facilitated greatly by the sequencing of many pathogen genomes and the incorporation of genome data into user-friendly databases. The present paper shows how the database TDRtargets.org can identify proteins that might be considered good drug targets for diseases such as African sleeping sickness, Chagas disease, parasitic worm infections, tuberculosis, and malaria. These proteins may score highly in searches of the database because they are dissimilar to human proteins, are structurally similar to other “druggable” proteins, have functions that are easy to measure, and/or fulfill other criteria. Researchers can use the lists of high-scoring proteins as a basis for deciding which potential drug targets to pursue experimentally.
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Affiliation(s)
- Gregory J. Crowther
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
- * E-mail: (GJC); (SAR); (DSR); (WCVV); (FA)
| | - Dhanasekaran Shanmugam
- Department of Biology and Penn Genomics Institute, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Santiago J. Carmona
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de General San Martín, Buenos Aires, Argentina
| | - Maria A. Doyle
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | | | | | - Solomon Nwaka
- Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Stuart A. Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
- * E-mail: (GJC); (SAR); (DSR); (WCVV); (FA)
| | - David S. Roos
- Department of Biology and Penn Genomics Institute, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (GJC); (SAR); (DSR); (WCVV); (FA)
| | - Wesley C. Van Voorhis
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
- * E-mail: (GJC); (SAR); (DSR); (WCVV); (FA)
| | - Fernán Agüero
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de General San Martín, Buenos Aires, Argentina
- * E-mail: (GJC); (SAR); (DSR); (WCVV); (FA)
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Auld D, Simeonov A, Lea W. Literature Search and Review. Assay Drug Dev Technol 2010. [DOI: 10.1089/adt.2010.0803.lr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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