1
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Lindblom JR, Zhang X, Lehane AM. A pH Fingerprint Assay to Identify Inhibitors of Multiple Validated and Potential Antimalarial Drug Targets. ACS Infect Dis 2024; 10:1185-1200. [PMID: 38499199 PMCID: PMC11019546 DOI: 10.1021/acsinfecdis.3c00588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/22/2024] [Accepted: 02/09/2024] [Indexed: 03/20/2024]
Abstract
New drugs with novel modes of action are needed to safeguard malaria treatment. In recent years, millions of compounds have been tested for their ability to inhibit the growth of asexual blood-stage Plasmodium falciparum parasites, resulting in the identification of thousands of compounds with antiplasmodial activity. Determining the mechanisms of action of antiplasmodial compounds informs their further development, but remains challenging. A relatively high proportion of compounds identified as killing asexual blood-stage parasites show evidence of targeting the parasite's plasma membrane Na+-extruding, H+-importing pump, PfATP4. Inhibitors of PfATP4 give rise to characteristic changes in the parasite's internal [Na+] and pH. Here, we designed a "pH fingerprint" assay that robustly identifies PfATP4 inhibitors while simultaneously allowing the detection of (and discrimination between) inhibitors of the lactate:H+ transporter PfFNT, which is a validated antimalarial drug target, and the V-type H+ ATPase, which was suggested as a possible target of the clinical candidate ZY19489. In our pH fingerprint assays and subsequent secondary assays, ZY19489 did not show evidence for the inhibition of pH regulation by the V-type H+ ATPase, suggesting that it has a different mode of action in the parasite. The pH fingerprint assay also has the potential to identify protonophores, inhibitors of the acid-loading Cl- transporter(s) (for which the molecular identity(ies) remain elusive), and compounds that act through inhibition of either the glucose transporter PfHT or glycolysis. The pH fingerprint assay therefore provides an efficient starting point to match a proportion of antiplasmodial compounds with their mechanisms of action.
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Affiliation(s)
| | | | - Adele M. Lehane
- Research School of Biology, Australian National University, Canberra, Australian Capital
Territory 2600, Australia
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2
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Ashton TD, Dans MG, Favuzza P, Ngo A, Lehane AM, Zhang X, Qiu D, Chandra Maity B, De N, Schindler KA, Yeo T, Park H, Uhlemann AC, Churchyard A, Baum J, Fidock DA, Jarman KE, Lowes KN, Baud D, Brand S, Jackson PF, Cowman AF, Sleebs BE. Optimization of 2,3-Dihydroquinazolinone-3-carboxamides as Antimalarials Targeting PfATP4. J Med Chem 2023; 66:3540-3565. [PMID: 36812492 PMCID: PMC10009754 DOI: 10.1021/acs.jmedchem.2c02092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
There is an urgent need to populate the antimalarial clinical portfolio with new candidates because of resistance against frontline antimalarials. To discover new antimalarial chemotypes, we performed a high-throughput screen of the Janssen Jumpstarter library against the Plasmodium falciparum asexual blood-stage parasite and identified the 2,3-dihydroquinazolinone-3-carboxamide scaffold. We defined the SAR and found that 8-substitution on the tricyclic ring system and 3-substitution of the exocyclic arene produced analogues with potent activity against asexual parasites equivalent to clinically used antimalarials. Resistance selection and profiling against drug-resistant parasite strains revealed that this antimalarial chemotype targets PfATP4. Dihydroquinazolinone analogues were shown to disrupt parasite Na+ homeostasis and affect parasite pH, exhibited a fast-to-moderate rate of asexual kill, and blocked gametogenesis, consistent with the phenotype of clinically used PfATP4 inhibitors. Finally, we observed that optimized frontrunner analogue WJM-921 demonstrates oral efficacy in a mouse model of malaria.
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Affiliation(s)
- Trent D Ashton
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Madeline G Dans
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Paola Favuzza
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Anna Ngo
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra 2601, Australia
| | - Xinxin Zhang
- Research School of Biology, Australian National University, Canberra 2601, Australia
| | - Deyun Qiu
- Research School of Biology, Australian National University, Canberra 2601, Australia
| | | | - Nirupam De
- TCG Lifesciences Pvt. Ltd., Saltlake Sec-V, Kolkata 700091, West Bengal, India
| | - Kyra A Schindler
- Department of Microbiology & Immunology, Columbia University, Irving Medical Center, New York, New York 10032, United States
| | - Tomas Yeo
- Department of Microbiology & Immunology, Columbia University, Irving Medical Center, New York, New York 10032, United States
| | - Heekuk Park
- Department of Microbiology & Immunology, Columbia University, Irving Medical Center, New York, New York 10032, United States
| | - Anne-Catrin Uhlemann
- Department of Microbiology & Immunology, Columbia University, Irving Medical Center, New York, New York 10032, United States
| | - Alisje Churchyard
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ U.K
| | - Jake Baum
- Department of Life Sciences, Imperial College London, South Kensington SW7 2AZ U.K.,School of Biomedical Sciences, University of New South Wales, Sydney 2031, Australia
| | - David A Fidock
- Department of Microbiology & Immunology, Columbia University, Irving Medical Center, New York, New York 10032, United States.,Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University, Irving Medical Center, New York, New York 10032, United States
| | - Kate E Jarman
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Kym N Lowes
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Delphine Baud
- Medicines for Malaria Venture, ICC, Route de Pré-Bois 20, 1215 Geneva, Switzerland
| | - Stephen Brand
- Medicines for Malaria Venture, ICC, Route de Pré-Bois 20, 1215 Geneva, Switzerland
| | - Paul F Jackson
- Global Public Health, Janssen R&D LLC, La Jolla, California 92121, United States
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
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3
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Qiu D, Pei JV, Rosling JEO, Thathy V, Li D, Xue Y, Tanner JD, Penington JS, Aw YTV, Aw JYH, Xu G, Tripathi AK, Gnadig NF, Yeo T, Fairhurst KJ, Stokes BH, Murithi JM, Kümpornsin K, Hasemer H, Dennis ASM, Ridgway MC, Schmitt EK, Straimer J, Papenfuss AT, Lee MCS, Corry B, Sinnis P, Fidock DA, van Dooren GG, Kirk K, Lehane AM. A G358S mutation in the Plasmodium falciparum Na + pump PfATP4 confers clinically-relevant resistance to cipargamin. Nat Commun 2022; 13:5746. [PMID: 36180431 PMCID: PMC9525273 DOI: 10.1038/s41467-022-33403-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 09/16/2022] [Indexed: 11/30/2022] Open
Abstract
Diverse compounds target the Plasmodium falciparum Na+ pump PfATP4, with cipargamin and (+)-SJ733 the most clinically-advanced. In a recent clinical trial for cipargamin, recrudescent parasites emerged, with most having a G358S mutation in PfATP4. Here, we show that PfATP4G358S parasites can withstand micromolar concentrations of cipargamin and (+)-SJ733, while remaining susceptible to antimalarials that do not target PfATP4. The G358S mutation in PfATP4, and the equivalent mutation in Toxoplasma gondii ATP4, decrease the sensitivity of ATP4 to inhibition by cipargamin and (+)-SJ733, thereby protecting parasites from disruption of Na+ regulation. The G358S mutation reduces the affinity of PfATP4 for Na+ and is associated with an increase in the parasite’s resting cytosolic [Na+]. However, no defect in parasite growth or transmissibility is observed. Our findings suggest that PfATP4 inhibitors in clinical development should be tested against PfATP4G358S parasites, and that their combination with unrelated antimalarials may mitigate against resistance development. In a recent clinical trial for oral administration of cipargamin in individuals with malaria, there was an emergence of recrudescent parasites with a G358S mutation in PfATP4. In this work, the authors investigate the effect of this mutation on the function of the ATPase, on parasite growth and susceptibility to antimalarial drugs.
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Affiliation(s)
- Deyun Qiu
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Jinxin V Pei
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - James E O Rosling
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Vandana Thathy
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Dongdi Li
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Yi Xue
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - John D Tanner
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Jocelyn Sietsma Penington
- Bioinformatic Division, The Walter & Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia
| | - Yi Tong Vincent Aw
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Jessica Yi Han Aw
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Guoyue Xu
- Department of Molecular Microbiology & Immunology and Johns Hopkins Malaria Institute, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
| | - Abhai K Tripathi
- Department of Molecular Microbiology & Immunology and Johns Hopkins Malaria Institute, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
| | - Nina F Gnadig
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Tomas Yeo
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Kate J Fairhurst
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Barbara H Stokes
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - James M Murithi
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | | | - Heath Hasemer
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Adelaide S M Dennis
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Melanie C Ridgway
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | | | - Judith Straimer
- Novartis Institute for Tropical Diseases, Emeryville, CA, 94608, USA
| | - Anthony T Papenfuss
- Bioinformatic Division, The Walter & Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Marcus C S Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
| | - Ben Corry
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Photini Sinnis
- Department of Molecular Microbiology & Immunology and Johns Hopkins Malaria Institute, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
| | - David A Fidock
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA.,Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia.
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4
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Lopes EA, Mestre R, Fontinha D, Legac J, Pei JV, Sanches-Vaz M, Mori M, Lehane AM, Rosenthal PJ, Prudêncio M, Santos MM. Discovery of spirooxadiazoline oxindoles with dual-stage antimalarial activity. Eur J Med Chem 2022; 236:114324. [DOI: 10.1016/j.ejmech.2022.114324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/24/2022] [Accepted: 03/25/2022] [Indexed: 12/21/2022]
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5
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Tse EG, Aithani L, Anderson M, Cardoso-Silva J, Cincilla G, Conduit GJ, Galushka M, Guan D, Hallyburton I, Irwin BWJ, Kirk K, Lehane AM, Lindblom JCR, Lui R, Matthews S, McCulloch J, Motion A, Ng HL, Öeren M, Robertson MN, Spadavecchio V, Tatsis VA, van Hoorn WP, Wade AD, Whitehead TM, Willis P, Todd MH. An Open Drug Discovery Competition: Experimental Validation of Predictive Models in a Series of Novel Antimalarials. J Med Chem 2021; 64:16450-16463. [PMID: 34748707 DOI: 10.1021/acs.jmedchem.1c00313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The Open Source Malaria (OSM) consortium is developing compounds that kill the human malaria parasite, Plasmodium falciparum, by targeting PfATP4, an essential ion pump on the parasite surface. The structure of PfATP4 has not been determined. Here, we describe a public competition created to develop a predictive model for the identification of PfATP4 inhibitors, thereby reducing project costs associated with the synthesis of inactive compounds. Competition participants could see all entries as they were submitted. In the final round, featuring private sector entrants specializing in machine learning methods, the best-performing models were used to predict novel inhibitors, of which several were synthesized and evaluated against the parasite. Half possessed biological activity, with one featuring a motif that the human chemists familiar with this series would have dismissed as "ill-advised". Since all data and participant interactions remain in the public domain, this research project "lives" and may be improved by others.
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Affiliation(s)
- Edwin G Tse
- School of Pharmacy, University College London, London WC1N 1AX, U.K
| | - Laksh Aithani
- Exscientia Ltd., The Schrödinger Building, Oxford Science Park, Oxford OX4 4GE, U.K
| | - Mark Anderson
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Jonathan Cardoso-Silva
- Department of Informatics, Faculty of Natural and Mathematical Sciences, King's College London, London WC2B 4BG, U.K
| | | | - Gareth J Conduit
- Intellegens Ltd., Eagle Labs, Chesterton Road, Cambridge CB4 3AZ, U.K.,Theory of Condensed Matter Group, Cavendish Laboratories, University of Cambridge, Cambridge CB3 0HE, U.K
| | | | - Davy Guan
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Irene Hallyburton
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee DD1 5EH, U.K
| | - Benedict W J Irwin
- Theory of Condensed Matter Group, Cavendish Laboratories, University of Cambridge, Cambridge CB3 0HE, U.K.,Optibrium Ltd. Blenheim House, Denny End Road, Cambridge CB25 9QE, U.K
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Julia C R Lindblom
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Raymond Lui
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Slade Matthews
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - James McCulloch
- Kellerberrin, 6 Wharf Rd, Balmain, Sydney, NSW 2041, Australia
| | - Alice Motion
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Ho Leung Ng
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan Kansas 66506, United States
| | - Mario Öeren
- Optibrium Ltd. Blenheim House, Denny End Road, Cambridge CB25 9QE, U.K
| | - Murray N Robertson
- Strathclyde Institute Of Pharmacy And Biomedical Sciences, University of Strathclyde, Glasgow G4 ORE, U.K
| | | | - Vasileios A Tatsis
- Exscientia Ltd., The Schrödinger Building, Oxford Science Park, Oxford OX4 4GE, U.K
| | - Willem P van Hoorn
- Exscientia Ltd., The Schrödinger Building, Oxford Science Park, Oxford OX4 4GE, U.K
| | - Alexander D Wade
- Theory of Condensed Matter Group, Cavendish Laboratories, University of Cambridge, Cambridge CB3 0HE, U.K
| | | | - Paul Willis
- Medicines for Malaria Venture, PO Box 1826, 20 rte de Pre-Bois, 1215 Geneva 15, Switzerland
| | - Matthew H Todd
- School of Pharmacy, University College London, London WC1N 1AX, U.K
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6
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Gilson PR, Kumarasingha R, Thompson J, Zhang X, Penington JS, Kalhor R, Bullen HE, Lehane AM, Dans MG, de Koning-Ward TF, Holien JK, Soares da Costa TP, Hulett MD, Buskes MJ, Crabb BS, Kirk K, Papenfuss AT, Cowman AF, Abbott BM. A 4-cyano-3-methylisoquinoline inhibitor of Plasmodium falciparum growth targets the sodium efflux pump PfATP4. Sci Rep 2019; 9:10292. [PMID: 31311978 PMCID: PMC6635429 DOI: 10.1038/s41598-019-46500-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/28/2019] [Indexed: 12/31/2022] Open
Abstract
We developed a novel series of antimalarial compounds based on a 4-cyano-3-methylisoquinoline. Our lead compound MB14 achieved modest inhibition of the growth in vitro of the human malaria parasite, Plasmodium falciparum. To identify its biological target we selected for parasites resistant to MB14. Genome sequencing revealed that all resistant parasites bore a single point S374R mutation in the sodium (Na+) efflux transporter PfATP4. There are many compounds known to inhibit PfATP4 and some are under preclinical development. MB14 was shown to inhibit Na+ dependent ATPase activity in parasite membranes, consistent with the compound targeting PfATP4 directly. PfATP4 inhibitors cause swelling and lysis of infected erythrocytes, attributed to the accumulation of Na+ inside the intracellular parasites and the resultant parasite swelling. We show here that inhibitor-induced lysis of infected erythrocytes is dependent upon the parasite protein RhopH2, a component of the new permeability pathways that are induced by the parasite in the erythrocyte membrane. These pathways mediate the influx of Na+ into the infected erythrocyte and their suppression via RhopH2 knockdown limits the accumulation of Na+ within the parasite hence protecting the infected erythrocyte from lysis. This study reveals a role for the parasite-induced new permeability pathways in the mechanism of action of PfATP4 inhibitors.
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Affiliation(s)
- Paul R Gilson
- Burnet Institute, Melbourne, Victoria, 3004, Australia. .,Monash University, Melbourne, Victoria, 3800, Australia.
| | | | - Jennifer Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia
| | - Xinxin Zhang
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | | | - Robabeh Kalhor
- La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Madeline G Dans
- Burnet Institute, Melbourne, Victoria, 3004, Australia.,School of Medicine, Deakin University, Waurn Ponds, Victoria, 3216, Australia
| | | | - Jessica K Holien
- St. Vincent's Institute of Medical Research, Melbourne, Victoria, 3065, Australia
| | | | - Mark D Hulett
- La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Brendan S Crabb
- Burnet Institute, Melbourne, Victoria, 3004, Australia.,Monash University, Melbourne, Victoria, 3800, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Anthony T Papenfuss
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
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7
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Lehane AM, Dennis ASM, Bray KO, Li D, Rajendran E, McCoy JM, McArthur HM, Winterberg M, Rahimi F, Tonkin CJ, Kirk K, van Dooren GG. Characterization of the ATP4 ion pump in Toxoplasma gondii. J Biol Chem 2019; 294:5720-5734. [PMID: 30723156 DOI: 10.1074/jbc.ra118.006706] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/31/2019] [Indexed: 12/22/2022] Open
Abstract
The Plasmodium falciparum ATPase PfATP4 is the target of a diverse range of antimalarial compounds, including the clinical drug candidate cipargamin. PfATP4 was originally annotated as a Ca2+ transporter, but recent evidence suggests that it is a Na+ efflux pump, extruding Na+ in exchange for H+ Here we demonstrate that ATP4 proteins belong to a clade of P-type ATPases that are restricted to apicomplexans and their closest relatives. We employed a variety of genetic and physiological approaches to investigate the ATP4 protein of the apicomplexan Toxoplasma gondii, TgATP4. We show that TgATP4 is a plasma membrane protein. Knockdown of TgATP4 had no effect on resting pH or Ca2+ but rendered parasites unable to regulate their cytosolic Na+ concentration ([Na+]cyt). PfATP4 inhibitors caused an increase in [Na+]cyt and a cytosolic alkalinization in WT but not TgATP4 knockdown parasites. Parasites in which TgATP4 was knocked down or disrupted exhibited a growth defect, attributable to reduced viability of extracellular parasites. Parasites in which TgATP4 had been disrupted showed reduced virulence in mice. These results provide evidence for ATP4 proteins playing a key conserved role in Na+ regulation in apicomplexan parasites.
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Affiliation(s)
- Adele M Lehane
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia,
| | - Adelaide S M Dennis
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Katherine O Bray
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Dongdi Li
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Esther Rajendran
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - James M McCoy
- the Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC 3052, Australia, and.,the Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Hillary M McArthur
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Markus Winterberg
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Farid Rahimi
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Christopher J Tonkin
- the Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC 3052, Australia, and.,the Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kiaran Kirk
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia,
| | - Giel G van Dooren
- From the Research School of Biology, Australian National University, Canberra, ACT 2601, Australia,
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8
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Uboldi AD, Wilde ML, McRae EA, Stewart RJ, Dagley LF, Yang L, Katris NJ, Hapuarachchi SV, Coffey MJ, Lehane AM, Botte CY, Waller RF, Webb AI, McConville MJ, Tonkin CJ. Protein kinase A negatively regulates Ca2+ signalling in Toxoplasma gondii. PLoS Biol 2018; 16:e2005642. [PMID: 30208022 PMCID: PMC6152992 DOI: 10.1371/journal.pbio.2005642] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 09/24/2018] [Accepted: 08/20/2018] [Indexed: 11/18/2022] Open
Abstract
The phylum Apicomplexa comprises a group of obligate intracellular parasites that alternate between intracellular replicating stages and actively motile extracellular forms that move through tissue. Parasite cytosolic Ca2+ signalling activates motility, but how this is switched off after invasion is complete to allow for replication to begin is not understood. Here, we show that the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A catalytic subunit 1 (PKAc1) of Toxoplasma is responsible for suppression of Ca2+ signalling upon host cell invasion. We demonstrate that PKAc1 is sequestered to the parasite periphery by dual acylation of PKA regulatory subunit 1 (PKAr1). Upon genetic depletion of PKAc1 we show that newly invaded parasites exit host cells shortly thereafter, in a perforin-like protein 1 (PLP-1)-dependent fashion. Furthermore, we demonstrate that loss of PKAc1 prevents rapid down-regulation of cytosolic [Ca2+] levels shortly after invasion. We also provide evidence that loss of PKAc1 sensitises parasites to cyclic GMP (cGMP)-induced Ca2+ signalling, thus demonstrating a functional link between cAMP and these other signalling modalities. Together, this work provides a new paradigm in understanding how Toxoplasma and related apicomplexan parasites regulate infectivity. Central to pathogenesis and infectivity of Toxoplasma and related parasites is their ability to move through tissue, invade host cells, and establish a replicative niche. Ca2+-dependent signalling pathways are important for activating motility, host cell invasion, and egress, yet how this signalling is turned off after invasion is unclear. Here, we show that a cAMP-dependent protein kinase A (PKA) is essential for rapid suppression of Ca2+ signalling upon completion of host cell invasion. Parasites lacking this kinase rapidly invoke an egress program to re-exit host cells, thus preventing the establishment of a stable infection. This finding therefore highlights the first factor required for Toxoplasma (and any related apicomplexan parasite) to switch from invasive to the replicative forms.
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Affiliation(s)
- Alessandro D. Uboldi
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Mary-Louise Wilde
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Emi A. McRae
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Rebecca J. Stewart
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Laura F. Dagley
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Luning Yang
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- School of Medicine, Tsinghua University, Beijing, China
| | - Nicholas J. Katris
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- Institute of Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | | | - Michael J. Coffey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Adele M. Lehane
- Research School of Biology, The Australian National University, A.C.T., Australia
| | - Cyrille Y. Botte
- Institute of Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | - Ross F. Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Andrew I. Webb
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology, Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Christopher J. Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- * E-mail:
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9
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Lawrence N, Dennis ASM, Lehane AM, Ehmann A, Harvey PJ, Benfield AH, Cheneval O, Henriques ST, Craik DJ, McMorran BJ. Defense Peptides Engineered from Human Platelet Factor 4 Kill Plasmodium by Selective Membrane Disruption. Cell Chem Biol 2018; 25:1140-1150.e5. [PMID: 30033131 DOI: 10.1016/j.chembiol.2018.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 06/01/2018] [Accepted: 06/25/2018] [Indexed: 11/29/2022]
Abstract
Malaria is a serious threat to human health and additional classes of antimalarial drugs are greatly needed. The human defense protein, platelet factor 4 (PF4), has intrinsic antiplasmodial activity but also undesirable chemokine properties. We engineered a peptide containing the isolated PF4 antiplasmodial domain, which through cyclization, retained the critical structure of the parent protein. The peptide, cPF4PD, killed cultured blood-stage Plasmodium falciparum with low micromolar potency by specific disruption of the parasite digestive vacuole. Its mechanism of action involved selective penetration and accumulation inside the intraerythrocytic parasite without damaging the host cell or parasite membranes; it did not accumulate in uninfected cells. This selective activity was accounted for by observations of the peptide's specific binding and penetration of membranes with exposed negatively charged phospholipid headgroups. Our findings highlight the tremendous potential of the cPF4PD scaffold for developing antimalarial peptide drugs with a distinct and selective mechanism of action.
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Affiliation(s)
- Nicole Lawrence
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Adelaide S M Dennis
- Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
| | - Adele M Lehane
- Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
| | - Anna Ehmann
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia
| | - Peta J Harvey
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Aurélie H Benfield
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Olivier Cheneval
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Sónia Troeira Henriques
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Brendan J McMorran
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia.
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10
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Rosling JEO, Ridgway MC, Summers RL, Kirk K, Lehane AM. Biochemical characterization and chemical inhibition of PfATP4-associated Na +-ATPase activity in Plasmodium falciparum membranes. J Biol Chem 2018; 293:13327-13337. [PMID: 29986883 DOI: 10.1074/jbc.ra118.003640] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/26/2018] [Indexed: 11/06/2022] Open
Abstract
The antimalarial activity of chemically diverse compounds, including the clinical candidate cipargamin, has been linked to the ATPase PfATP4 in the malaria-causing parasite Plasmodium falciparum The characterization of PfATP4 has been hampered by the inability thus far to achieve its functional expression in a heterologous system. Here, we optimized a membrane ATPase assay to probe the function of PfATP4 and its chemical sensitivity. We found that cipargamin inhibited the Na+-dependent ATPase activity present in P. falciparum membranes from WT parasites and that its potency was reduced in cipargamin-resistant PfATP4-mutant parasites. The cipargamin-sensitive fraction of membrane ATPase activity was inhibited by all 28 of the compounds in the "Malaria Box" shown previously to disrupt ion regulation in P. falciparum in a cipargamin-like manner. This is consistent with PfATP4 being the direct target of these compounds. Characterization of the cipargamin-sensitive ATPase activity yielded data consistent with PfATP4 being a Na+ transporter that is sensitive to physiologically relevant perturbations of pH, but not of [K+] or [Ca2+]. With an apparent Km for ATP of 0.2 mm and an apparent Km for Na+ of 16-17 mm, the protein is predicted to operate at below its half-maximal rate under normal physiological conditions, allowing the rate of Na+ efflux to increase in response to an increase in cytosolic [Na+]. In membranes from a cipargamin-resistant PfATP4-mutant line, the apparent Km for Na+ is slightly elevated. Our study provides new insights into the biochemical properties and chemical sensitivity of an important new antimalarial drug target.
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Affiliation(s)
- James E O Rosling
- From the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Melanie C Ridgway
- From the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Robert L Summers
- From the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Kiaran Kirk
- From the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Adele M Lehane
- From the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
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11
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Dennis ASM, Rosling JEO, Lehane AM, Kirk K. Diverse antimalarials from whole-cell phenotypic screens disrupt malaria parasite ion and volume homeostasis. Sci Rep 2018; 8:8795. [PMID: 29892073 PMCID: PMC5995868 DOI: 10.1038/s41598-018-26819-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/14/2018] [Indexed: 11/17/2022] Open
Abstract
Four hundred structurally diverse drug-like compounds comprising the Medicines for Malaria Venture's 'Pathogen Box' were screened for their effect on a range of physiological parameters in asexual blood-stage malaria (Plasmodium falciparum) parasites. Eleven of these compounds were found to perturb parasite Na+, pH and volume in a manner consistent with inhibition of the putative Na+ efflux P-type ATPase PfATP4. All eleven compounds fell within the subset of 125 compounds included in the Pathogen Box on the basis of their having been identified as potent inhibitors of the growth of asexual blood-stage P. falciparum parasites. All eleven compounds inhibited the Na+-dependent ATPase activity of parasite membranes and showed reduced efficacy against parasites carrying mutations in PfATP4. This study increases the number of chemically diverse structures known to show a 'PfATP4-associated' phenotype, and adds to emerging evidence that a high proportion (7-9%) of the structurally diverse antimalarial compounds identified in whole cell phenotypic screens share the same mechanism of action, exerting their antimalarial effect via an interaction with PfATP4.
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Affiliation(s)
- Adelaide S M Dennis
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - James E O Rosling
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia.
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia.
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12
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McCoy JM, Stewart RJ, Uboldi AD, Li D, Schröder J, Scott NE, Papenfuss AT, Lehane AM, Foster LJ, Tonkin CJ. A forward genetic screen identifies a negative regulator of rapid Ca 2+-dependent cell egress (MS1) in the intracellular parasite Toxoplasma gondii. J Biol Chem 2017; 292:7662-7674. [PMID: 28258212 DOI: 10.1074/jbc.m117.775114] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/27/2017] [Indexed: 12/20/2022] Open
Abstract
Toxoplasma gondii, like all apicomplexan parasites, uses Ca2+ signaling pathways to activate gliding motility to power tissue dissemination and host cell invasion and egress. A group of "plant-like" Ca2+-dependent protein kinases (CDPKs) transduces cytosolic Ca2+ flux into enzymatic activity, but how they function is poorly understood. To investigate how Ca2+ signaling activates egress through CDPKs, we performed a forward genetic screen to isolate gain-of-function mutants from an egress-deficient cdpk3 knockout strain. We recovered mutants that regained the ability to egress from host cells that harbored mutations in the gene Suppressor of Ca2+-dependent Egress 1 (SCE1). Global phosphoproteomic analysis showed that SCE1 deletion restored many Δcdpk3-dependent phosphorylation events to near wild-type levels. We also show that CDPK3-dependent SCE1 phosphorylation is required to relieve its suppressive activity to potentiate egress. In summary, our work has uncovered a novel component and suppressor of Ca2+-dependent cell egress during Toxoplasma lytic growth.
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Affiliation(s)
- James M McCoy
- From the Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia.,the Departments of Medical Biology.,Computing and Information Systems,University of Melbourne, Victoria 3010, Australia
| | - Rebecca J Stewart
- From the Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia.,the Departments of Medical Biology.,Computing and Information Systems,University of Melbourne, Victoria 3010, Australia
| | - Alessandro D Uboldi
- From the Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia.,the Departments of Medical Biology.,Computing and Information Systems,University of Melbourne, Victoria 3010, Australia
| | - Dongdi Li
- the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Jan Schröder
- From the Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia.,the Departments of Medical Biology.,the Peter MacCallum Cancer Institute, Victoria 3000, Australia, and
| | - Nicollas E Scott
- the University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Anthony T Papenfuss
- From the Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia.,the Departments of Medical Biology.,the Peter MacCallum Cancer Institute, Victoria 3000, Australia, and
| | - Adele M Lehane
- the Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Leonard J Foster
- the University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Christopher J Tonkin
- From the Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia, .,the Departments of Medical Biology
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13
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Hapuarachchi SV, Cobbold SA, Shafik SH, Dennis ASM, McConville MJ, Martin RE, Kirk K, Lehane AM. The Malaria Parasite's Lactate Transporter PfFNT Is the Target of Antiplasmodial Compounds Identified in Whole Cell Phenotypic Screens. PLoS Pathog 2017; 13:e1006180. [PMID: 28178359 PMCID: PMC5298231 DOI: 10.1371/journal.ppat.1006180] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 01/11/2017] [Indexed: 11/19/2022] Open
Abstract
In this study the ‘Malaria Box’ chemical library comprising 400 compounds with antiplasmodial activity was screened for compounds that perturb the internal pH of the malaria parasite, Plasmodium falciparum. Fifteen compounds induced an acidification of the parasite cytosol. Two of these did so by inhibiting the parasite’s formate nitrite transporter (PfFNT), which mediates the H+-coupled efflux from the parasite of lactate generated by glycolysis. Both compounds were shown to inhibit lactate transport across the parasite plasma membrane, and the transport of lactate by PfFNT expressed in Xenopus laevis oocytes. PfFNT inhibition caused accumulation of lactate in parasitised erythrocytes, and swelling of both the parasite and parasitised erythrocyte. Long-term exposure of parasites to one of the inhibitors gave rise to resistant parasites with a mutant form of PfFNT that showed reduced inhibitor sensitivity. This study provides the first evidence that PfFNT is a druggable antimalarial target. The emergence and spread of Plasmodium falciparum strains resistant to leading antimalarial drugs has intensified the need to discover and develop drugs that kill the parasite via new mechanisms. Here we screened compounds that are known to inhibit P. falciparum growth for their effects on the pH inside the parasite. We identified fifteen compounds that decrease the pH inside the parasite, and determined the mechanism by which two of these, MMV007839 and MMV000972, disrupt pH and kill the parasite. The two compounds were found to inhibit the P. falciparum formate nitrite transporter (PfFNT), a transport protein that is located on the parasite surface and that serves to remove the waste product lactic acid from the parasite. The compounds inhibited both the H+-coupled transport of lactate across the parasite plasma membrane and the transport of lactate by PfFNT expressed in Xenopus oocytes. In addition to disrupting pH, PfFNT inhibition led to a build-up of lactate in the parasite-infected red blood cell and the swelling of both the parasite and the infected red blood cell. Exposing parasites to MMV007839 over a prolonged time period gave rise to resistant parasites with a mutant form of PfFNT that was less sensitive to the compound. This study validates PfFNT as a novel antimalarial drug target.
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Affiliation(s)
| | - Simon A Cobbold
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Sarah H Shafik
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Adelaide S M Dennis
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Malcolm J McConville
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Rowena E Martin
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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14
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Hewitt SN, Dranow DM, Horst BG, Abendroth JA, Forte B, Hallyburton I, Jansen C, Baragaña B, Choi R, Rivas KL, Hulverson MA, Dumais M, Edwards TE, Lorimer DD, Fairlamb AH, Gray DW, Read KD, Lehane AM, Kirk K, Myler PJ, Wernimont A, Walpole C, Stacy R, Barrett LK, Gilbert IH, Van Voorhis WC. Biochemical and Structural Characterization of Selective Allosteric Inhibitors of the Plasmodium falciparum Drug Target, Prolyl-tRNA-synthetase. ACS Infect Dis 2017; 3:34-44. [PMID: 27798837 PMCID: PMC5241706 DOI: 10.1021/acsinfecdis.6b00078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Plasmodium falciparum (Pf) prolyl-tRNA synthetase (ProRS) is one of the few chemical-genetically validated drug targets for malaria, yet highly selective inhibitors have not been described. In this paper, approximately 40,000 compounds were screened to identify compounds that selectively inhibit PfProRS enzyme activity versus Homo sapiens (Hs) ProRS. X-ray crystallography structures were solved for apo, as well as substrate- and inhibitor-bound forms of PfProRS. We identified two new inhibitors of PfProRS that bind outside the active site. These two allosteric inhibitors showed >100 times specificity for PfProRS compared to HsProRS, demonstrating this class of compounds could overcome the toxicity related to HsProRS inhibition by halofuginone and its analogues. Initial medicinal chemistry was performed on one of the two compounds, guided by the cocrystallography of the compound with PfProRS, and the results can instruct future medicinal chemistry work to optimize these promising new leads for drug development against malaria.
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Affiliation(s)
- Stephen Nakazawa Hewitt
- Center for Emerging
and Reemerging Infectious Disease (CERID), University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
| | - David M. Dranow
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
- Beryllium Discovery Corporation, 7869 N.E. Day Road West, Bainbridge Island, Washington 98110, United States
| | - Benjamin G. Horst
- Center for Emerging
and Reemerging Infectious Disease (CERID), University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
| | - Jan A. Abendroth
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
- Beryllium Discovery Corporation, 7869 N.E. Day Road West, Bainbridge Island, Washington 98110, United States
| | - Barbara Forte
- Drug Discovery Unit (DDU), Division of Biological Chemistry and Drug
Discovery, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Irene Hallyburton
- Drug Discovery Unit (DDU), Division of Biological Chemistry and Drug
Discovery, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Chimed Jansen
- Drug Discovery Unit (DDU), Division of Biological Chemistry and Drug
Discovery, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Beatriz Baragaña
- Drug Discovery Unit (DDU), Division of Biological Chemistry and Drug
Discovery, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Ryan Choi
- Center for Emerging
and Reemerging Infectious Disease (CERID), University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
| | - Kasey L. Rivas
- Center for Emerging
and Reemerging Infectious Disease (CERID), University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
| | - Matthew A. Hulverson
- Center for Emerging
and Reemerging Infectious Disease (CERID), University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
| | - Mitchell Dumais
- Center for Emerging
and Reemerging Infectious Disease (CERID), University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
| | - Thomas E. Edwards
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
- Beryllium Discovery Corporation, 7869 N.E. Day Road West, Bainbridge Island, Washington 98110, United States
| | - Donald D. Lorimer
- Beryllium Discovery Corporation, 7869 N.E. Day Road West, Bainbridge Island, Washington 98110, United States
| | - Alan H. Fairlamb
- Drug Discovery Unit (DDU), Division of Biological Chemistry and Drug
Discovery, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - David W. Gray
- Drug Discovery Unit (DDU), Division of Biological Chemistry and Drug
Discovery, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Kevin D. Read
- Drug Discovery Unit (DDU), Division of Biological Chemistry and Drug
Discovery, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Adele M. Lehane
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Kiaran Kirk
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Peter J. Myler
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, Washington 98109, United States
- Departments of Global Health and Biomedical
Informatics and Medical Education, University of Washington, Seattle, Washington 98195, United States
| | - Amy Wernimont
- Structure-guided Drug Discovery Coalition (SDDC), Structural Genomic Consortium, 101 College Street, MaRS South Tower, Suite 700, Toronto, Ontario M5G 1L7, Canada
| | - Chris Walpole
- Structure-guided Drug Discovery Coalition (SDDC), Structural Genomic Consortium, 101 College Street, MaRS South Tower, Suite 700, Toronto, Ontario M5G 1L7, Canada
| | - Robin Stacy
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, Washington 98109, United States
| | - Lynn K. Barrett
- Center for Emerging
and Reemerging Infectious Disease (CERID), University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
| | - Ian H. Gilbert
- Drug Discovery Unit (DDU), Division of Biological Chemistry and Drug
Discovery, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Wesley C. Van Voorhis
- Center for Emerging
and Reemerging Infectious Disease (CERID), University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington 98109, United States
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15
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Richards SN, Nash MN, Baker ES, Webster MW, Lehane AM, Shafik SH, Martin RE. Molecular Mechanisms for Drug Hypersensitivity Induced by the Malaria Parasite's Chloroquine Resistance Transporter. PLoS Pathog 2016; 12:e1005725. [PMID: 27441371 PMCID: PMC4956231 DOI: 10.1371/journal.ppat.1005725] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/03/2016] [Indexed: 01/23/2023] Open
Abstract
Mutations in the Plasmodium falciparum ‘chloroquine resistance transporter’ (PfCRT) confer resistance to chloroquine (CQ) and related antimalarials by enabling the protein to transport these drugs away from their targets within the parasite’s digestive vacuole (DV). However, CQ resistance-conferring isoforms of PfCRT (PfCRTCQR) also render the parasite hypersensitive to a subset of structurally-diverse pharmacons. Moreover, mutations in PfCRTCQR that suppress the parasite’s hypersensitivity to these molecules simultaneously reinstate its sensitivity to CQ and related drugs. We sought to understand these phenomena by characterizing the functions of PfCRTCQR isoforms that cause the parasite to become hypersensitive to the antimalarial quinine or the antiviral amantadine. We achieved this by measuring the abilities of these proteins to transport CQ, quinine, and amantadine when expressed in Xenopus oocytes and complemented this work with assays that detect the drug transport activity of PfCRT in its native environment within the parasite. Here we describe two mechanistic explanations for PfCRT-induced drug hypersensitivity. First, we show that quinine, which normally accumulates inside the DV and therewithin exerts its antimalarial effect, binds extremely tightly to the substrate-binding site of certain isoforms of PfCRTCQR. By doing so it likely blocks the normal physiological function of the protein, which is essential for the parasite’s survival, and the drug thereby gains an additional killing effect. In the second scenario, we show that although amantadine also sequesters within the DV, the parasite’s hypersensitivity to this drug arises from the PfCRTCQR-mediated transport of amantadine from the DV into the cytosol, where it can better access its antimalarial target. In both cases, the mutations that suppress hypersensitivity also abrogate the ability of PfCRTCQR to transport CQ, thus explaining why rescue from hypersensitivity restores the parasite’s sensitivity to this antimalarial. These insights provide a foundation for understanding clinically-relevant observations of inverse drug susceptibilities in the malaria parasite. In acquiring resistance to one drug, many pathogens and cancer cells become hypersensitive to other drugs. This phenomenon could be exploited to combat existing drug resistance and to delay the emergence of resistance to new drugs. However, much remains to be understood about the mechanisms that underlie drug hypersensitivity in otherwise drug-resistant microbes. Here, we describe two mechanisms by which the Plasmodium falciparum ‘chloroquine resistance transporter’ (PfCRT) causes the malaria parasite to become hypersensitive to structurally-diverse drugs. First, we show that an antimalarial drug that normally exerts its killing effect within the parasite’s digestive vacuole is also able to bind extremely tightly to certain forms of PfCRT. This activity will block the natural, essential function of the protein and thereby provide the drug with an additional killing effect. The second mechanism arises when a cytosolic-acting drug that normally sequesters within the digestive vacuole is leaked back into the cytosol via PfCRT. In both cases, mutations that suppress hypersensitivity also abrogate the ability of PfCRT to transport chloroquine, thus explaining why rescue from hypersensitivity restores the parasite’s sensitivity to this antimalarial. These insights provide a foundation for understanding and exploiting the hypersensitivity of chloroquine-resistant parasites to several of the current antimalarials.
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Affiliation(s)
- Sashika N. Richards
- Research School of Biology, Australian National University, Canberra, Australia
| | - Megan N. Nash
- Research School of Biology, Australian National University, Canberra, Australia
| | - Eileen S. Baker
- Research School of Biology, Australian National University, Canberra, Australia
| | - Michael W. Webster
- Research School of Biology, Australian National University, Canberra, Australia
| | - Adele M. Lehane
- Research School of Biology, Australian National University, Canberra, Australia
| | - Sarah H. Shafik
- Research School of Biology, Australian National University, Canberra, Australia
| | - Rowena E. Martin
- Research School of Biology, Australian National University, Canberra, Australia
- * E-mail:
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16
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van Schalkwyk DA, Nash MN, Shafik SH, Summers RL, Lehane AM, Smith PJ, Martin RE. Verapamil-Sensitive Transport of Quinacrine and Methylene Blue via the Plasmodium falciparum Chloroquine Resistance Transporter Reduces the Parasite's Susceptibility to these Tricyclic Drugs. J Infect Dis 2015; 213:800-10. [PMID: 26503982 DOI: 10.1093/infdis/jiv509] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/15/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND It is becoming increasingly apparent that certain mutations in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) alter the parasite's susceptibility to diverse compounds. Here we investigated the interaction of PfCRT with 3 tricyclic compounds that have been used to treat malaria (quinacrine [QC] and methylene blue [MB]) or to study P. falciparum (acridine orange [AO]). METHODS We measured the antiplasmodial activities of QC, MB, and AO against chloroquine-resistant and chloroquine-sensitive P. falciparum and determined whether QC and AO affect the accumulation and activity of chloroquine in these parasites. We also assessed the ability of mutant (PfCRT(Dd2)) and wild-type (PfCRT(D10)) variants of the protein to transport QC, MB, and AO when expressed at the surface of Xenopus laevis oocytes. RESULTS Chloroquine resistance-conferring isoforms of PfCRT reduced the susceptibility of the parasite to QC, MB, and AO. In chloroquine-resistant (but not chloroquine-sensitive) parasites, AO and QC increased the parasite's accumulation of, and susceptibility to, chloroquine. All 3 compounds were shown to bind to PfCRT(Dd2), and the transport of QC and MB via this protein was saturable and inhibited by the chloroquine resistance-reverser verapamil. CONCLUSIONS Our findings reveal that the PfCRT(Dd2)-mediated transport of tricyclic antimalarials reduces the parasite's susceptibility to these drugs.
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Affiliation(s)
| | - Megan N Nash
- Research School of Biology, Australian National University, Canberra, Australia
| | - Sarah H Shafik
- Research School of Biology, Australian National University, Canberra, Australia
| | - Robert L Summers
- Research School of Biology, Australian National University, Canberra, Australia
| | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, Australia
| | - Peter J Smith
- Division of Pharmacology, Department of Medicine, University of Cape Town, Rondebosch, South Africa
| | - Rowena E Martin
- Research School of Biology, Australian National University, Canberra, Australia
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17
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Petersen I, Gabryszewski SJ, Johnston GL, Dhingra SK, Ecker A, Lewis RE, de Almeida MJ, Straimer J, Henrich PP, Palatulan E, Johnson DJ, Coburn-Flynn O, Sanchez C, Lehane AM, Lanzer M, Fidock DA. Balancing drug resistance and growth rates via compensatory mutations in the Plasmodium falciparum chloroquine resistance transporter. Mol Microbiol 2015; 97:381-95. [PMID: 25898991 DOI: 10.1111/mmi.13035] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2015] [Indexed: 11/28/2022]
Abstract
The widespread use of chloroquine to treat Plasmodium falciparum infections has resulted in the selection and dissemination of variant haplotypes of the primary resistance determinant PfCRT. These haplotypes have encountered drug pressure and within-host competition with wild-type drug-sensitive parasites. To examine these selective forces in vitro, we genetically engineered P. falciparum to express geographically diverse PfCRT haplotypes. Variant alleles from the Philippines (PH1 and PH2, which differ solely by the C72S mutation) both conferred a moderate gain of chloroquine resistance and a reduction in growth rates in vitro. Of the two, PH2 showed higher IC50 values, contrasting with reduced growth. Furthermore, a highly mutated pfcrt allele from Cambodia (Cam734) conferred moderate chloroquine resistance and enhanced growth rates, when tested against wild-type pfcrt in co-culture competition assays. These three alleles mediated cross-resistance to amodiaquine, an antimalarial drug widely used in Africa. Each allele, along with the globally prevalent Dd2 and 7G8 alleles, rendered parasites more susceptible to lumefantrine, the partner drug used in the leading first-line artemisinin-based combination therapy. These data reveal ongoing region-specific evolution of PfCRT that impacts drug susceptibility and relative fitness in settings of mixed infections, and raise important considerations about optimal agents to treat chloroquine-resistant malaria.
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Affiliation(s)
- Ines Petersen
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.,Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany
| | - Stanislaw J Gabryszewski
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Geoffrey L Johnston
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.,School of International and Public Affairs, Columbia University, New York, NY, 10027, USA
| | - Satish K Dhingra
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.,Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902, USA
| | - Andrea Ecker
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Rebecca E Lewis
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | | | - Judith Straimer
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Philipp P Henrich
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Eugene Palatulan
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - David J Johnson
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Olivia Coburn-Flynn
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Cecilia Sanchez
- Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany
| | - Adele M Lehane
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Michael Lanzer
- Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, 69120, Heidelberg, Germany
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA.,Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA
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18
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Lehane AM, Ridgway MC, Baker E, Kirk K. Diverse chemotypes disrupt ion homeostasis in the Malaria parasite. Mol Microbiol 2014; 94:327-39. [PMID: 25145582 DOI: 10.1111/mmi.12765] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2014] [Indexed: 01/09/2023]
Abstract
The antimalarial spiroindolones disrupt Plasmodium falciparum Na(+) regulation and induce an alkalinization of the parasite cytosol. It has been proposed that they do so by inhibiting PfATP4, a parasite plasma membrane P-type ATPase postulated to export Na(+) and import H(+) equivalents. Here, we screened the 400 antiplasmodial compounds of the open access 'Malaria Box' for their effects on parasite ion regulation. Twenty eight compounds affected parasite Na(+) and pH regulation in a manner consistent with PfATP4 inhibition. Six of these, with chemically diverse structures, were selected for further analysis. All six showed reduced antiplasmodial activity against spiroindolone-resistant parasites carrying mutations in pfatp4. We exposed parasites to incrementally increasing concentrations of two of the six compounds and in both cases obtained resistant parasites with mutations in pfatp4. The finding that diverse chemotypes have an apparently similar mechanism of action indicates that PfATP4 may be a significant Achilles' heel for the parasite.
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Affiliation(s)
- Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia
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19
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Deane KJ, Summers RL, Lehane AM, Martin RE, Barrow RA. Chlorpheniramine Analogues Reverse Chloroquine Resistance in Plasmodium falciparum by Inhibiting PfCRT. ACS Med Chem Lett 2014; 5:576-81. [PMID: 24900883 DOI: 10.1021/ml5000228] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 03/03/2014] [Indexed: 12/17/2022] Open
Abstract
The emergence and spread of malaria parasites that are resistant to chloroquine (CQ) has been a disaster for world health. The antihistamine chlorpheniramine (CP) partially resensitizes CQ-resistant (CQR) parasites to CQ but possesses little intrinsic antiplasmodial activity. Mutations in the parasite's CQ resistance transporter (PfCRT) confer resistance to CQ by enabling the protein to transport the drug away from its site of action, and it is thought that resistance-reversers such as CP exert their effect by blocking this CQ transport activity. Here, a series of new structural analogues and homologues of CP have been synthesized. We show that these compounds (along with other in vitro CQ resistance-reversers) inhibit the transport of CQ via a resistance-conferring form of PfCRT expressed in Xenopus laevis oocytes. Furthermore, the level of PfCRT-inhibition was found to correlate well with both the restoration of CQ accumulation and the level of CQ resensitization in CQR parasites.
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Affiliation(s)
- Karen J. Deane
- Research
School of Chemistry and ‡Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Robert L. Summers
- Research
School of Chemistry and ‡Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Adele M. Lehane
- Research
School of Chemistry and ‡Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Rowena E. Martin
- Research
School of Chemistry and ‡Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Russell A. Barrow
- Research
School of Chemistry and ‡Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
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20
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Hrycyna CA, Summers RL, Lehane AM, Pires MM, Namanja H, Bohn K, Kuriakose J, Ferdig M, Henrich PP, Fidock DA, Kirk K, Chmielewski J, Martin RE. Quinine dimers are potent inhibitors of the Plasmodium falciparum chloroquine resistance transporter and are active against quinoline-resistant P. falciparum. ACS Chem Biol 2014; 9:722-30. [PMID: 24369685 DOI: 10.1021/cb4008953] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Chloroquine (CQ) resistance in the human malaria parasite Plasmodium falciparum is primarily conferred by mutations in the "chloroquine resistance transporter" (PfCRT). The resistance-conferring form of PfCRT (PfCRT(CQR)) mediates CQ resistance by effluxing the drug from the parasite's digestive vacuole, the acidic compartment in which CQ exerts its antiplasmodial effect. PfCRT(CQR) can also decrease the parasite's susceptibility to other quinoline drugs, including the current antimalarials quinine and amodiaquine. Here we describe interactions between PfCRT(CQR) and a series of dimeric quinine molecules using a Xenopus laevis oocyte system for the heterologous expression of PfCRT and using an assay that detects the drug-associated efflux of H(+) ions from the digestive vacuole in parasites that harbor different forms of PfCRT. The antiplasmodial activities of dimers 1 and 6 were also examined in vitro (against drug-sensitive and drug-resistant strains of P. falciparum) and in vivo (against drug-sensitive P. berghei). Our data reveal that the quinine dimers are the most potent inhibitors of PfCRT(CQR) reported to date. Furthermore, the lead compounds (1 and 6) were not effluxed by PfCRT(CQR) from the digestive vacuole but instead accumulated to very high levels within this organelle. Both 1 and 6 exhibited in vitro antiplasmodial activities that were inversely correlated with CQ. Moreover, the additional parasiticidal effect exerted by 1 and 6 in the drug-resistant parasites was attributable, at least in part, to their ability to inhibit PfCRT(CQR). This highlights the potential for devising new antimalarial therapies that exploit inherent weaknesses in a key resistance mechanism of P. falciparum.
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Affiliation(s)
- Christine A. Hrycyna
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Robert L. Summers
- Research
School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Adele M. Lehane
- Research
School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Marcos M. Pires
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Hilda Namanja
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Kelsey Bohn
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jerrin Kuriakose
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Michael Ferdig
- Department
of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Philipp P. Henrich
- Department
of Microbiology and Immunology, Columbia University, New York, New York 10027, United States
| | - David A. Fidock
- Department
of Microbiology and Immunology, Columbia University, New York, New York 10027, United States
- Division
of Infectious Diseases, Department of Medicine, Columbia University, New York, New York 10027, United States
| | - Kiaran Kirk
- Research
School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Jean Chmielewski
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Rowena E. Martin
- Research
School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
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21
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Lehane AM, McDevitt CA, Kirk K, Fidock DA. Degrees of chloroquine resistance in Plasmodium - is the redox system involved? Int J Parasitol Drugs Drug Resist 2012; 2:47-57. [PMID: 22773965 DOI: 10.1016/j.ijpddr.2011.11.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Chloroquine (CQ) was once a very effective antimalarial drug that, at its peak, was consumed in the hundreds of millions of doses per year. The drug acts against the Plasmodium parasite during the asexual intraerythrocytic phase of its lifecycle. Unfortunately, clinical resistance to this drug is now widespread. Questions remain about precisely how CQ kills malaria parasites, and by what means some CQ-resistant (CQR) parasites can withstand much higher concentrations of the drug than others that also fall in the CQR category. In this review we investigate the evidence for and against the proposal that CQ kills parasites by generating oxidative stress. Further, we examine a long-held idea that the glutathione system of malaria parasites plays a role in CQ resistance. We conclude that there is strong evidence that glutathione levels modulate CQ response in the rodent malaria species P. berghei, but that a role for redox in contributing to the degree of CQ resistance in species infectious to humans has not been firmly established.
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Affiliation(s)
- Adele M Lehane
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA
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22
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Lehane AM, Kirk K. Efflux of a range of antimalarial drugs and 'chloroquine resistance reversers' from the digestive vacuole in malaria parasites with mutant PfCRT. Mol Microbiol 2010; 77:1039-51. [PMID: 20598081 DOI: 10.1111/j.1365-2958.2010.07272.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chloroquine-resistant malaria parasites (Plasmodium falciparum) show an increased leak of H(+) ions from their internal digestive vacuole in the presence of chloroquine. This phenomenon has been attributed to the transport of chloroquine, together with H(+), out of the digestive vacuole (and hence away from its site of action) via a mutant form of the parasite's chloroquine resistance transporter (PfCRT). Here, using transfectant parasite lines, we show that a range of other antimalarial drugs, as well as various 'chloroquine resistance reversers' induce an increased leak of H(+) from the digestive vacuole of parasites expressing mutant PfCRT, consistent with these compounds being substrates for mutant forms, but not the wild-type form, of PfCRT. For some compounds there were significant differences observed between parasites having the African/Asian Dd2 form of PfCRT and those with the South American 7G8 form of PfCRT, consistent with there being differences in the transport properties of the two mutant proteins. The finding that chloroquine resistance reversers are substrates for mutant PfCRT has implications for the mechanism of action of this class of compound.
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Affiliation(s)
- Adele M Lehane
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Kiaran Kirk
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
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23
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Henry RI, Cobbold SA, Allen RJW, Khan A, Hayward R, Lehane AM, Bray PG, Howitt SM, Biagini GA, Saliba KJ, Kirk K. An acid-loading chloride transport pathway in the intraerythrocytic malaria parasite, Plasmodium falciparum. J Biol Chem 2010; 285:18615-26. [PMID: 20332090 DOI: 10.1074/jbc.m110.120980] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The intraerythrocytic malaria parasite exerts tight control over its ionic composition. In this study, a combination of fluorescent ion indicators and (36)Cl(-) flux measurements was used to investigate the transport of Cl(-) and the Cl(-)-dependent transport of "H(+)-equivalents" in mature (trophozoite stage) parasites, isolated from their host erythrocytes. Removal of extracellular Cl(-), resulting in an outward [Cl(-)] gradient, gave rise to a cytosolic alkalinization (i.e. a net efflux of H(+)-equivalents). This was reversed on restoration of extracellular Cl(-). The flux of H(+)-equivalents was inhibited by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid and, when measured in ATP-depleted parasites, showed a pronounced dependence on the pH of the parasite cytosol; the flux was low at cytosolic pH values < 7.2 but increased steeply with cytosolic pH at values > 7.2. (36)Cl(-) influx measurements revealed the presence of a Cl(-) uptake mechanism with characteristics similar to those of the Cl(-)-dependent H(+)-equivalent flux. The intracellular concentration of Cl(-) in the parasite was estimated to be approximately 48 mm in situ. The data are consistent with the intraerythrocytic parasite having in its plasma membrane a 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid-sensitive transporter that, under physiological conditions, imports Cl(-) together with H(+)-equivalents, resulting in an intracellular Cl(-) concentration well above that which would occur if Cl(-) ions were distributed passively in accordance with the parasite's large, inwardly negative membrane potential.
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Affiliation(s)
- Roselani I Henry
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
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24
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Abstract
The human malaria parasite, Plasmodium falciparum, has long been known to have a homologue of the human 'multidrug resistance' P-glycoprotein. P-glycoprotein is an ABC transporter that pumps drugs from multidrug-resistant cancer cells. The malaria parasite's P-glycoprotein homologue, Pgh1, is known to influence the sensitivity of malaria parasites to a diverse range of antimalarial drugs, but the mechanism by which it does so has remained obscure. In a new paper, Sanchez et al. report the successful functional expression of Pgh1 in Xenopus laevis oocytes and provide the first direct demonstration of the ability of Pgh1 to transport drugs. The work provides important new insights into the mechanism by which Pgh1 influences malaria parasite drug sensitivity.
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Affiliation(s)
- Kevin J Saliba
- Biochemistry and Molecular Biology, School of Biology, The Australian National University, Canberra, ACT 0200, Australia.
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25
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Lehane AM, Saliba KJ. Common dietary flavonoids inhibit the growth of the intraerythrocytic malaria parasite. BMC Res Notes 2008; 1:26. [PMID: 18710482 PMCID: PMC2518919 DOI: 10.1186/1756-0500-1-26] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 06/18/2008] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Flavonoids are abundant plant phenolic compounds. More than 6000 have been identified to date, and some have been shown to possess antiparasitic activity. Here we investigate the effects of a range of common dietary flavonoids on the growth of two strains of the human malaria parasite Plasmodium falciparum. FINDINGS A chloroquine-sensitive (3D7) and a chloroquine-resistant (7G8) strain of P. falciparum were tested for in vitro susceptibility to a range of individual dietary flavonoids and flavonoid combinations. Parasite susceptibility was measured in 96-well plates over 96 h using a previously described [3H]hypoxanthine incorporation assay. Of the eleven flavonoids tested, eight showed antiplasmodial activity against the 3D7 strain (with IC50 values between 11 and 66 muM), and all showed activity against the 7G8 strain (with IC50 values between 12 and 76 muM). The most active compound against both strains was luteolin, with IC50 values of 11 +/- 1 muM and 12 +/- 1 muM for 3D7 and 7G8, respectively. Luteolin was found to prevent the progression of parasite growth beyond the young trophozoite stage, and did not affect parasite susceptibility to the antimalarial drugs chloroquine or artemisinin. Combining low concentrations of flavonoids was found to produce an apparent additive antiplasmodial effect. CONCLUSION Certain common dietary flavonoids inhibit the intraerythrocytic growth of the 3D7 and 7G8 strains of P. falciparum. Flavonoid combinations warrant further investigation as antiplasmodial agents.
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Affiliation(s)
- Adele M Lehane
- School of Biochemistry and Molecular Biology, The Australian National University, Canberra, ACT 0200, Australia.
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26
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Lehane AM, Hayward R, Saliba KJ, Kirk K. A verapamil-sensitive chloroquine-associated H+ leak from the digestive vacuole in chloroquine-resistant malaria parasites. J Cell Sci 2008; 121:1624-32. [PMID: 18445688 DOI: 10.1242/jcs.016758] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chloroquine resistance in the malaria parasite Plasmodium falciparum has made malaria increasingly difficult to control. Chloroquine-resistant parasites accumulate less chloroquine than their chloroquine-sensitive counterparts; however, the mechanism underlying this remains unclear. The primary site of accumulation and antimalarial action of chloroquine is the internal acidic digestive vacuole of the parasite, the acidity of which is maintained by inwardly-directed H+ pumps, working against the (outward) leak of H+. In this study we have investigated the leak of H+ from the digestive vacuole of the parasite by monitoring the alkalinisation of the vacuole following inhibition of the H+-pumping V-type ATPase by concanamycin A. The rates of alkalinisation observed in three chloroquine-resistant strains were two- to fourfold higher than those measured in three chloroquine-sensitive strains. On addition of chloroquine there was a dramatic increase in the rate of alkalinisation in the chloroquine-resistant strains, whereas chloroquine caused the rate of alkalinisation to decrease in the chloroquine-sensitive strains. The chloroquine-associated increase in the rate of alkalinisation seen in chloroquine-resistant parasites was inhibited by the chloroquine-resistance reversal agent verapamil. The data are consistent with the hypothesis that in chloroquine-resistant parasites chloroquine effluxes from the digestive vacuole, in association with H+, via a verapamil-sensitive pathway.
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Affiliation(s)
- Adele M Lehane
- School of Biochemistry and Molecular Biology, The Australian National University, Canberra ACT 0200, Australia
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27
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Lehane AM, Marchetti RV, Spry C, van Schalkwyk DA, Teng R, Kirk K, Saliba KJ. Feedback inhibition of pantothenate kinase regulates pantothenol uptake by the malaria parasite. J Biol Chem 2007; 282:25395-405. [PMID: 17581817 DOI: 10.1074/jbc.m704610200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To survive, the human malaria parasite Plasmodium falciparum must acquire pantothenate (vitamin B5) from the external medium. Pantothenol (provitamin B5) inhibits parasite growth by competing with pantothenate for pantothenate kinase, the first enzyme in the coenzyme A biosynthesis pathway. In this study we investigated pantothenol uptake by P. falciparum and in doing so gained insights into the regulation of the parasite's coenzyme A biosynthesis pathway. Pantothenol was shown to enter P. falciparum-infected erythrocytes via two routes, the furosemide-inhibited "new permeation pathways" induced by the parasite in the infected erythrocyte membrane (the sole access route for pantothenate) and a second, furosemide-insensitive pathway. Having entered the erythrocyte, pantothenol is taken up by the intracellular parasite via a mechanism showing functional characteristics distinct from those of the parasite's pantothenate uptake mechanism. On reaching the parasite cytosol, pantothenol is phosphorylated and thereby trapped by pantothenate kinase, shown here to be under feedback inhibition control by coenzyme A. Furosemide reduced this inherent feedback inhibition by competing with coenzyme A for binding to pantothenate kinase, thereby increasing pantothenol uptake.
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Affiliation(s)
- Adele M Lehane
- School of Biochemistry and Molecular Biology, Medical School, The Australian National University, Canberra, ACT 0200, Australia
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28
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Lehane AM, Saliba KJ, Allen RJW, Kirk K. Choline uptake into the malaria parasite is energized by the membrane potential. Biochem Biophys Res Commun 2004; 320:311-7. [PMID: 15219828 DOI: 10.1016/j.bbrc.2004.05.164] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Indexed: 11/23/2022]
Abstract
The uptake by the intraerythrocytic malaria parasite of the phospholipid precursor choline was investigated in parasites 'isolated' from their host cells by saponin permeabilization of the erythrocyte membrane. Choline is transported across the parasite plasma membrane then phosphorylated and thereby trapped within the parasite. Choline influx was inhibited competitively by quinine. It increased with increasing extracellular pH, decreased on depolarization of the parasite plasma membrane with a protonophore or by increasing extracellular [K+], and increased in response to hyperpolarization of the membrane by decreasing extracellular [K+] or by addition of the K+ channel blocker Cs+. In ATP-depleted parasites choline was taken up but not phosphorylated. Under these conditions, imposition of an inwardly negative membrane potential using the K+ ionophore valinomycin resulted in the accumulation of choline to an intracellular concentration more than 15-fold higher than the extracellular concentration. Choline influx is therefore an electrogenic process, energized by the parasite plasma membrane potential.
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Affiliation(s)
- Adele M Lehane
- School of Biochemistry and Molecular Biology, Faculty of Science, Australian National University, Canberra, ACT 0200, Australia
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