1
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Chen X, Zhao H, Wang C, Hamed M, Shang Q, Yang Y, Diao X, Sun X, Hu W, Jiang X, Zhang Y, Hirsch AKH, Wu D, Zhuang J. Two natural compounds as potential inhibitors against the Helicobacter pylori and Acinetobacter baumannii IspD enzymes. Int J Antimicrob Agents 2024; 63:107160. [PMID: 38537721 DOI: 10.1016/j.ijantimicag.2024.107160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/27/2024] [Accepted: 03/21/2024] [Indexed: 04/21/2024]
Abstract
In a vast majority of bacteria, protozoa and plants, the methylerythritol phosphate (MEP) pathway is utilized for the synthesis of isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP), which are precursors for isoprenoids. Isoprenoids, such as cholesterol and coenzyme Q, play a variety of crucial roles in physiological activities, including cell-membrane formation, protein degradation, cell apoptosis, and transcription regulation. In contrast, humans employ the mevalonate (MVA) pathway for the production of IDP and DMADP, rendering proteins in the MEP pathway appealing targets for antimicrobial agents. This pathway consists of seven consecutive enzymatic reactions, of which 4-diphosphocytidyl-2C-methyl-D-erythritol synthase (IspD) and 2C-methyl-D-erythritol 2,4-cyclodiphosphate synthase (IspF) catalyze the third and fifth steps, respectively. In this study, we characterized the enzymatic activities and protein structures of Helicobacter pylori IspDF and Acinetobacter baumannii IspD. Then, using the direct interaction-based thermal shift assay, we conducted a compound screening of an approved drug library and identified 27 hit compounds potentially binding to AbIspD. Among them, two natural products, rosmarinic acid and tanshinone IIA sodium sulfonate, exhibited inhibitory activities against HpIspDF and AbIspD, by competing with one of the substrates, MEP. Moreover, tanshinone IIA sodium sulfonate also demonstrated certain antibacterial effects against H. pylori. In summary, we identified two IspD inhibitors from approved ingredients, broadening the scope for antibiotic discovery targeting the MEP pathway.
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Affiliation(s)
- Xiaoyu Chen
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Huilin Zhao
- Department of Pathogenic Biology, College of Basic Medicine, Binzhou Medical University, Yantai, China
| | - Chuandong Wang
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Mostafa Hamed
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Saarbrücken, Germany
| | - Qinghong Shang
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Yating Yang
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xiaotong Diao
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xiangnan Sun
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Wei Hu
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xukai Jiang
- National Glycoengineering Research Center, Shandong University, Qingdao, China
| | - Youming Zhang
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Anna K H Hirsch
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Saarbrücken, Germany; Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Dalei Wu
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
| | - Jingjing Zhuang
- Helmholtz International Lab, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China; Marine College, Shandong University, Weihai, China.
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2
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Cheuka PM, Njaria P, Mayoka G, Funjika E. Emerging Drug Targets for Antimalarial Drug Discovery: Validation and Insights into Molecular Mechanisms of Function. J Med Chem 2024; 67:838-863. [PMID: 38198596 DOI: 10.1021/acs.jmedchem.3c01828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Approximately 619,000 malaria deaths were reported in 2021, and resistance to recommended drugs, including artemisinin-combination therapies (ACTs), threatens malaria control. Treatment failure with ACTs has been found to be as high as 93% in northeastern Thailand, and parasite mutations responsible for artemisinin resistance have already been reported in some African countries. Therefore, there is an urgent need to identify alternative treatments with novel targets. In this Perspective, we discuss some promising antimalarial drug targets, including enzymes involved in proteolysis, DNA and RNA metabolism, protein synthesis, and isoprenoid metabolism. Other targets discussed are transporters, Plasmodium falciparum acetyl-coenzyme A synthetase, N-myristoyltransferase, and the cyclic guanosine monophosphate-dependent protein kinase G. We have outlined mechanistic details, where these are understood, underpinning the biological roles and hence druggability of such targets. We believe that having a clear understanding of the underlying chemical interactions is valuable to medicinal chemists in their quest to design appropriate inhibitors.
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Affiliation(s)
- Peter Mubanga Cheuka
- Department of Chemistry, School of Natural Sciences, University of Zambia, P.O. Box 32379, Lusaka 10101, Zambia
| | - Paul Njaria
- Department of Pharmacognosy and Pharmaceutical Chemistry, Kenyatta University, P.O. Box 14548-00400, Nairobi 00100, Kenya
| | - Godfrey Mayoka
- Department of Pharmacology and Pharmacognosy, School of Pharmacy, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi 00100, Kenya
| | - Evelyn Funjika
- Department of Chemistry, School of Natural Sciences, University of Zambia, P.O. Box 32379, Lusaka 10101, Zambia
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3
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Zimbres FM, Merino EF, Butschek GJ, Butler JH, Ducongé F, Cassera MB. Aptamer-Based Imaging of Polyisoprenoids in the Malaria Parasite. Molecules 2023; 29:178. [PMID: 38202761 PMCID: PMC10780415 DOI: 10.3390/molecules29010178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Dolichols are isoprenoid end-products of the mevalonate and 2C-methyl-D-erythritol-4-phosphate pathways. The synthesis of dolichols is initiated with the addition of several molecules of isopentenyl diphosphate to farnesyl diphosphate. This reaction is catalyzed by a cis-prenyltransferase and leads to the formation of polyprenyl diphosphate. Subsequent steps involve the dephosphorylation and reduction of the α-isoprene unit by a polyprenol reductase, resulting in the generation of dolichol. The size of the dolichol varies, depending on the number of isoprene units incorporated. In eukaryotes, dolichols are synthesized as a mixture of four or more different lengths. Their biosynthesis is predicted to occur in the endoplasmic reticulum, where dolichols play an essential role in protein glycosylation. In this study, we have developed a selection of aptamers targeting dolichols and enhanced their specificity by incorporating fatty acids for negative selection. One aptamer showed high enrichment and specificity for linear polyisoprenoids containing at least one oxygen atom, such as an alcohol or aldehyde, in the α-isoprene unit. The selected aptamer proved to be a valuable tool for the subcellular localization of polyisoprenoids in the malaria parasite. To the best of our knowledge, this is the first time that polyisoprenoids have been localized within a cell using aptamer-based imaging techniques.
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Affiliation(s)
- Flavia M. Zimbres
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, GA 30602, USA
| | - Emilio F. Merino
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, GA 30602, USA
| | - Grant J. Butschek
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, GA 30602, USA
| | - Joshua H. Butler
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, GA 30602, USA
| | - Frédéric Ducongé
- French Atomic Energy Commission (CEA), Fundamental Research Division (DRF), Institute of Biology François Jacob (Jacob), Molecular Imaging Research Center, 92265 Fontenay-aux-Roses, France
- Neurodegenerative Diseases Laboratory, CNRS CEA UMR 9199, 92265 Fontenay-aux-Roses, France
- Paris-Saclay University, 92265 Fontenay-aux-Roses, France
| | - Maria B. Cassera
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, GA 30602, USA
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4
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Okada M, Sigala PA. The interdependence of isoprenoid synthesis and apicoplast biogenesis in malaria parasites. PLoS Pathog 2023; 19:e1011713. [PMID: 37883328 PMCID: PMC10602226 DOI: 10.1371/journal.ppat.1011713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023] Open
Abstract
Isoprenoid precursor synthesis is an ancient and fundamental function of plastid organelles and a critical metabolic activity of the apicoplast in Plasmodium malaria parasites [1-3]. Over the past decade, our understanding of apicoplast properties and functions has increased enormously [4], due in large part to our ability to rescue blood-stage parasites from apicoplast-specific dysfunctions by supplementing cultures with isopentenyl pyrophosphate (IPP), a key output of this organelle [5,6]. In this Pearl, we explore the interdependence between isoprenoid metabolism and apicoplast biogenesis in P. falciparum and highlight critical future questions to answer.
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Affiliation(s)
- Megan Okada
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah, United States
| | - Paul A. Sigala
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah, United States
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5
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Elahi R, Prigge ST. New insights into apicoplast metabolism in blood-stage malaria parasites. Curr Opin Microbiol 2023; 71:102255. [PMID: 36563485 PMCID: PMC9852000 DOI: 10.1016/j.mib.2022.102255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022]
Abstract
The apicoplast of Plasmodium falciparum is the only source of essential isoprenoid precursors and Coenzyme A (CoA) in the parasite. Isoprenoid precursor synthesis relies on the iron-sulfur cluster (FeS) cofactors produced within the apicoplast, rendering FeS synthesis an essential function of this organelle. Recent reports provide important insights into the roles of FeS cofactors and the use of isoprenoid precursors and CoA both inside and outside the apicoplast. Here, we review the recent insights into the roles of these metabolites in blood-stage malaria parasites and discuss new questions that have been raised in light of these discoveries.
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Affiliation(s)
- Rubayet Elahi
- Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, MD, USA; The Johns Hopkins Malaria Research Institute, Baltimore, MD, USA
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, MD, USA; The Johns Hopkins Malaria Research Institute, Baltimore, MD, USA.
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6
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Carlson EJ, Francis R, Liu Y, Li P, Lyon M, Santi CM, Hook DJ, Hawkinson JE, Georg GI. Discovery and Characterization of Multiple Classes of Human CatSper Blockers. ChemMedChem 2022; 17:e202000499. [PMID: 35644882 PMCID: PMC9378630 DOI: 10.1002/cmdc.202000499] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 05/25/2022] [Indexed: 11/25/2022]
Abstract
The cation channel of sperm (CatSper) is a validated target for nonhormonal male contraception, but it lacks selective blockers, hindering studies to establish its role in both motility and capacitation. Via an innovative calcium uptake assay utilizing human sperm we discovered novel inhibitors of CatSper function from a high-throughput screening campaign of 72,000 compounds. Preliminary SAR was established for seven hit series. HTS hits or their more potent analogs blocked potassium-induced depolarization and noncompetitively inhibited progesterone-induced CatSper activation. CatSper channel blockade was confirmed by patch clamp electrophysiology and these compounds inhibited progesterone- and prostaglandin E1-induced hyperactivated sperm motility. One of the hit compounds is a potent CatSper inhibitor with high selectivity for CatSper over hCav1.2, hNav1.5, moderate selectivity over hSlo3 and hERG, and low cytotoxicity and is therefore the most promising inhibitor identified in this study. These new CatSper blockers serve as useful starting points for chemical probe development and drug discovery efforts.
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Affiliation(s)
- Erick J. Carlson
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Rawle Francis
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Yutong Liu
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Ping Li
- Department of Obstetrics and GynecologyWashington University School of Medicine425 S. Euclid AvenueSt. LouisMO 63110USA
| | - Maximilian Lyon
- Department of Obstetrics and GynecologyWashington University School of Medicine425 S. Euclid AvenueSt. LouisMO 63110USA
| | - Celia M. Santi
- Department of Obstetrics and GynecologyWashington University School of Medicine425 S. Euclid AvenueSt. LouisMO 63110USA
| | - Derek J. Hook
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Jon E. Hawkinson
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
| | - Gunda I. Georg
- Department of Medicinal Chemistry andInstitute for Therapeutics Discovery and DevelopmentCollege of PharmacyUniversity of Minnesota717 Delaware Street, SEMinneapolisMN 55414USA
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7
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Synthesis, Structure−Activity Relationships, and Parasitological Profiling of Brussonol Derivatives as New Plasmodium falciparum Inhibitors. Pharmaceuticals (Basel) 2022; 15:ph15070814. [PMID: 35890113 PMCID: PMC9321043 DOI: 10.3390/ph15070814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 11/17/2022] Open
Abstract
Malaria is a parasitic disease caused by protozoan parasites from the genus Plasmodium. Plasmodium falciparum is the most prevalent species worldwide and the causative agent of severe malaria. The spread of resistance to the currently available antimalarial therapy is a major concern. Therefore, it is imperative to discover and develop new antimalarial drugs, which not only treat the disease but also control the emerging resistance. Brussonol is an icetexane derivative and a member of a family of diterpenoids that have been isolated from several terrestrial plants. Here, the synthesis and antiplasmodial profiling of a series of brussonol derivatives are reported. The compounds showed inhibitory activities in the low micromolar range against a panel of sensitive and resistant P. falciparum strains (IC50s = 5-16 μM). Moreover, brussonol showed fast-acting in vitro inhibition and an additive inhibitory behavior when combined with the antimalarial artesunate (FICindex~1). The mode of action investigation indicated that brussonol increased the cytosolic calcium levels within the parasite. Hence, the discovery of brussonol as a new scaffold endowed with antiplasmodial activity will enable us to design derivatives with improved properties to deliver new lead candidates for malaria.
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8
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Araveti PB, Vijay M, Kar PP, Varunan S, Srivastava A. MMV560185 from pathogen box induces extrinsic pathway of apoptosis in Theileria annulata infected bovine leucocytes. Int J Parasitol Drugs Drug Resist 2022; 18:20-31. [PMID: 35032948 PMCID: PMC8761611 DOI: 10.1016/j.ijpddr.2021.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/22/2021] [Accepted: 12/30/2021] [Indexed: 11/22/2022]
Abstract
Tropical theileriosis is a lymphoproliferative disease caused by the intracellular schizonts of Theileria annulata, an apicomplexan parasite. It causes severe infection in cattle and the untreated cattle would possibly die within 3–4 weeks of infection. The chemotherapy for this disease is largely dependent on the use of hydroxynaphthoquinone, namely buparvaquone. There have been reports recently of the development of resistance against this drug in T. annulata. Hence, identification of new drug molecule(s) or repurposing of existing drug molecule(s) against T. annulata is quite important. Here, we present the screening of 400 compounds included in the open-access Pathogen box from Medicine for Malaria Venture (MMV) to discover the novel compounds with potential inhibitory activity against T. annulata infected bovine leucocytes. We identified two compounds, MMV000062 and MMV560185, with IC50 values of 2.97 μM and 3.07 μM, respectively. MMV000062 and MMV560185 were found non-toxic to BoMac cells with CC50 values 34 μM and > 100 μM, respectively. The therapeutic indices of these compounds, MMV000062 and MMV560185, were calculated as more than 33 and 11, respectively. Further, it was observed that the parasite-infected cells under long-term culture were unable to recover with these compounds. We further deciphered that MMV560185 kills the infected cell by activation of TNFR-1 mediated extrinsic pathway of the apoptosis. The phenotypic characteristics of apoptosis were confirmed by Transmission Electron Microscopy. Our results suggest that it may be possible to develop MMV560185 further for chemotherapeutics of tropical theilerosis.
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Almolhim H, Ding S, Butler JH, Bremers EK, Butschek GJ, Slebodnick C, Merino EF, Rizopoulos Z, Totrov M, Cassera MB, Carlier PR. Enantiopure Benzofuran-2-carboxamides of 1-Aryltetrahydro-β-carbolines Are Potent Antimalarials In Vitro. ACS Med Chem Lett 2022; 13:371-376. [PMID: 35300082 PMCID: PMC8919387 DOI: 10.1021/acsmedchemlett.1c00697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/17/2022] [Indexed: 11/29/2022] Open
Abstract
The tetrahydro-β-carboline scaffold has proven fertile ground for the discovery of antimalarial agents (e.g., MMV008138 (1) and cipargamin (2)). Similarity searching of a publicly disclosed collection of antimalarial hits for molecules resembling 1 drew our attention to N2-acyl tetrahydro-β-carboline GNF-Pf-5009 ((±)-3b). Compound purchase, "analog by catalog", and independent synthesis of hits indicated the benzofuran-2-yl amide portion was required for in vitro efficacy against P. falciparum. Preparation of pure enantiomers demonstrated the pharmacological superiority of (R)-3b. Synthesis and evaluation of D- and F-ring substitution variants and benzofuran isosteres indicated a clear structure-activity relationship. Ultimately (R)-3b was tested in Plasmodium berghei-infected mice; unfavorable physicochemical properties may be responsible for the lack of oral efficacy.
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Affiliation(s)
- Hanan Almolhim
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Sha Ding
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Joshua H Butler
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Emily K Bremers
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Grant J Butschek
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Carla Slebodnick
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Emilio F Merino
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | | | - Maxim Totrov
- Molsoft LLC, 11999 Sorrento Valley Road, San Diego, California 92121, United States
| | - Maria B Cassera
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Paul R Carlier
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
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10
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Mathew J, Ding S, Kunz KA, Stacy EE, Butler JH, Haney RS, Merino EF, Butschek GJ, Rizopoulos Z, Totrov M, Cassera MB, Carlier PR. Malaria Box-Inspired Discovery of N-Aminoalkyl-β-carboline-3-carboxamides, a Novel Orally Active Class of Antimalarials. ACS Med Chem Lett 2022; 13:365-370. [PMID: 35300096 PMCID: PMC8919280 DOI: 10.1021/acsmedchemlett.1c00663] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/17/2022] [Indexed: 11/30/2022] Open
Abstract
Virtual ligand screening of a publicly available database of antimalarial hits using a pharmacophore derived from antimalarial MMV008138 identified TCMDC-140230, a tetrahydro-β-carboline amide, as worthy of exploration. All four stereoisomers of this structure were synthesized, but none potently inhibited growth of the malaria parasite Plasmodium falciparum. Interestingly, 7e, a minor byproduct of these syntheses, proved to be potent in vitro against P. falciparum and was orally efficacious (40 mg/kg) in an in vivo mouse model of malaria.
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Affiliation(s)
- Jopaul Mathew
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Sha Ding
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Kevin A Kunz
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Emily E Stacy
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Joshua H Butler
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Reagan S Haney
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Emilio F Merino
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Grant J Butschek
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | | | - Maxim Totrov
- Molsoft LLC, 11999 Sorrento Valley Road, San Diego, California 92121, United States
| | - Maria B Cassera
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Paul R Carlier
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 1040 Drillfield Drive, Blacksburg, Virginia 24061, United States
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11
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Okada M, Rajaram K, Swift RP, Mixon A, Maschek JA, Prigge ST, Sigala PA. Critical role for isoprenoids in apicoplast biogenesis by malaria parasites. eLife 2022; 11:73208. [PMID: 35257658 PMCID: PMC8959605 DOI: 10.7554/elife.73208] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 03/04/2022] [Indexed: 11/13/2022] Open
Abstract
Isopentenyl pyrophosphate (IPP) is an essential metabolic output of the apicoplast organelle in Plasmodium falciparum malaria parasites and is required for prenylation-dependent vesicular trafficking and other cellular processes. We have elucidated a critical and previously uncharacterized role for IPP in apicoplast biogenesis. Inhibiting IPP synthesis blocks apicoplast elongation and inheritance by daughter merozoites, and apicoplast biogenesis is rescued by exogenous IPP and polyprenols. Knockout of the only known isoprenoid-dependent apicoplast pathway, tRNA prenylation by MiaA, has no effect on blood-stage parasites and thus cannot explain apicoplast reliance on IPP. However, we have localized an annotated polyprenyl synthase (PPS) to the apicoplast. PPS knockdown is lethal to parasites, rescued by IPP and long- (C50) but not short-chain (≤C20) prenyl alcohols, and blocks apicoplast biogenesis, thus explaining apicoplast dependence on isoprenoid synthesis. We hypothesize that PPS synthesizes long-chain polyprenols critical for apicoplast membrane fluidity and biogenesis. This work critically expands the paradigm for isoprenoid utilization in malaria parasites and identifies a novel essential branch of apicoplast metabolism suitable for therapeutic targeting.
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Affiliation(s)
- Megan Okada
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Krithika Rajaram
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Russell P Swift
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Amanda Mixon
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - John Alan Maschek
- Metabolomics Core, University of Utah, Salt Lake City, United States
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Paul A Sigala
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
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12
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Kingston DGI, Cassera MB. Antimalarial Natural Products. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2022; 117:1-106. [PMID: 34977998 DOI: 10.1007/978-3-030-89873-1_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Natural products have made a crucial and unique contribution to human health, and this is especially true in the case of malaria, where the natural products quinine and artemisinin and their derivatives and analogues, have saved millions of lives. The need for new drugs to treat malaria is still urgent, since the most dangerous malaria parasite, Plasmodium falciparum, has become resistant to quinine and most of its derivatives and is becoming resistant to artemisinin and its derivatives. This volume begins with a short history of malaria and follows this with a summary of its biology. It then traces the fascinating history of the discovery of quinine for malaria treatment and then describes quinine's biosynthesis, its mechanism of action, and its clinical use, concluding with a discussion of synthetic antimalarial agents based on quinine's structure. The volume then covers the discovery of artemisinin and its development as the source of the most effective current antimalarial drug, including summaries of its synthesis and biosynthesis, its mechanism of action, and its clinical use and resistance. A short discussion of other clinically used antimalarial natural products leads to a detailed treatment of other natural products with significant antiplasmodial activity, classified by compound type. Although the search for new antimalarial natural products from Nature's combinatorial library is challenging, it is very likely to yield new antimalarial drugs. The chapter thus ends by identifying over ten natural products with development potential as clinical antimalarial agents.
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Affiliation(s)
- David G I Kingston
- Department of Chemistry and the Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Maria Belen Cassera
- Department of Biochemistry and Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, GA, 30602, USA
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13
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Abstract
Malaria parasites have three genomes: a nuclear genome, a mitochondrial genome, and an apicoplast genome. Since the apicoplast is a plastid organelle of prokaryotic origin and has no counterpart in the human host, it can be a source of novel targets for antimalarials. Plasmodium falciparum DNA gyrase (PfGyr) A and B subunits both have apicoplast-targeting signals. First, to test the predicted localization of this enzyme in the apicoplast and the breadth of its function at the subcellular level, nuclear-encoded PfGyrA was disrupted using CRISPR/Cas9 gene editing. Isopentenyl pyrophosphate (IPP) is known to rescue parasites from apicoplast inhibitors. Indeed, successful growth and characterization of PfΔGyrA was possible in the presence of IPP. PfGyrA disruption was accompanied by loss of plastid acyl-carrier protein (ACP) immunofluorescence and the plastid genome. Second, ciprofloxacin, an antibacterial gyrase inhibitor, has been used for malaria prophylaxis, but there is a need for a more detailed description of the mode of action of ciprofloxacin in malaria parasites. As predicted, PfΔGyrA clone supplemented with IPP was less sensitive to ciprofloxacin but not to the nuclear topoisomerase inhibitor etoposide. At high concentrations, however, ciprofloxacin continued to inhibit IPP-rescued PfΔGyrA, possibly suggesting that ciprofloxacin may have an additional nonapicoplast target in P. falciparum. Overall, we confirm that PfGyrA is an apicoplast enzyme in the malaria parasite, essential for blood-stage parasites, and a possible target of ciprofloxacin but perhaps not the only target.
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14
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Faheem, Kumar BK, Sekhar KVGC, Kunjiappan S, Jamalis J, Balaña-Fouce R, Sankaranarayanan M. Recent Update on the Anti-infective Potential of β-carboline Analogs. Mini Rev Med Chem 2021; 21:398-425. [PMID: 33001013 DOI: 10.2174/1389557520666201001130114] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 11/22/2022]
Abstract
β-Carboline, a naturally occurring indole alkaloid, holds a momentous spot in the field of medicinal chemistry due to its myriad of pharmacological actions like anticancer, antiviral, antibacterial, antifungal, antileishmanial, antimalarial, neuropharmacological, anti-inflammatory and antithrombotic among others. β-Carbolines exhibit their pharmacological activity via diverse mechanisms. This review provides a recent update (2015-2020) on the anti-infective potential of natural and synthetic β-carboline analogs focusing on its antibacterial, antifungal, antiviral, antimalarial, antileishmanial and antitrypanosomal properties. In cases where enough details are available, a note on its mechanism of action is also added.
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Affiliation(s)
- Faheem
- Medicinal Chemistry Research Laboratory, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Vidya Vihar, Pilani-333031, Rajasthan, India
| | - Banoth Karan Kumar
- Medicinal Chemistry Research Laboratory, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Vidya Vihar, Pilani-333031, Rajasthan, India
| | - Kondapalli Venkata Gowri Chandra Sekhar
- Department of Chemistry, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet Mandal, R.R. Dist. Hyderabad, 500078, Telangana, India
| | - Selvaraj Kunjiappan
- Department of Biotechnology, Kalasalingam Academy of Research and Education, Krishnankoil 626126, India
| | - Joazaizulfazli Jamalis
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru, Johor 81310, Malaysia
| | | | - Murugesan Sankaranarayanan
- Medicinal Chemistry Research Laboratory, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Vidya Vihar, Pilani-333031, Rajasthan, India
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15
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Swift RP, Rajaram K, Liu HB, Prigge ST. Dephospho-CoA kinase, a nuclear-encoded apicoplast protein, remains active and essential after Plasmodium falciparum apicoplast disruption. EMBO J 2021; 40:e107247. [PMID: 34031901 PMCID: PMC8365264 DOI: 10.15252/embj.2020107247] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/06/2021] [Accepted: 04/26/2021] [Indexed: 12/11/2022] Open
Abstract
Malaria parasites contain an essential organelle called the apicoplast that houses metabolic pathways for fatty acid, heme, isoprenoid, and iron–sulfur cluster synthesis. Surprisingly, malaria parasites can survive without the apicoplast as long as the isoprenoid precursor isopentenyl pyrophosphate (IPP) is supplemented in the growth medium, making it appear that isoprenoid synthesis is the only essential function of the organelle in blood‐stage parasites. In the work described here, we localized an enzyme responsible for coenzyme A synthesis, DPCK, to the apicoplast, but we were unable to delete DPCK, even in the presence of IPP. However, once the endogenous DPCK was complemented with the E. coli DPCK (EcDPCK), we were successful in deleting it. We were then able to show that DPCK activity is required for parasite survival through knockdown of the complemented EcDPCK. Additionally, we showed that DPCK enzyme activity remains functional and essential within the vesicles present after apicoplast disruption. These results demonstrate that while the apicoplast of blood‐stage P. falciparum parasites can be disrupted, the resulting vesicles remain biochemically active and are capable of fulfilling essential functions.
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Affiliation(s)
- Russell P Swift
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Krithika Rajaram
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Hans B Liu
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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16
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Kamboj A, Sihag B, Brar DS, Kaur A, Salunke DB. Structure activity relationship in β-carboline derived anti-malarial agents. Eur J Med Chem 2021; 221:113536. [PMID: 34058709 DOI: 10.1016/j.ejmech.2021.113536] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/21/2021] [Accepted: 05/02/2021] [Indexed: 11/28/2022]
Abstract
Malaria, even though an avoidable and treatable disease, can be fatal if ignored. Artemisinin Combination Therapy (ACT) and RTS, S/AS01 vaccine (Mosquirix™) are the only modest means available with humans to overcome malaria, a lethal affliction wreaking havoc across the globe. Employment of ACT is associated with problems such as 'Artemisinin Resistance' and the 'Hypnozoite conundrum' that hinder the complete eradication of malaria. In this view, the natural products specifically comprising β-carboline scaffold have shown good antiplasmodial responses against different strains of malaria. Taking these observations forward, researchers have performed structure-activity relationship (SAR) studies around three different β-carboline skeletons (tetrahydro β-carbolines, dihydro β-carbolines, β-carbolines) to design new β-carboline derived heterocyclic structures or modified naturally occurring derivatives. In addition, different approaches such as dimerization and linkage to other moieties have also been adopted to enhance the antimalarial activity. The present review describes a comprehensive SAR study encapsulating various natural and synthetic β-carbolines to elaborate upon the utility of these skeletons in designing drugs to subdue this deadly disease.
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Affiliation(s)
- Aarzoo Kamboj
- Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Binita Sihag
- Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Deshkanwar Singh Brar
- Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Arshpreet Kaur
- Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Deepak B Salunke
- Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India; National Interdisciplinary Centre of Vaccine, Immunotherapeutics and Antimicrobials, Panjab University, Chandigarh 160014, India.
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17
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Fabbri C, Trindade AO, Andrade FS, Souza MFD, Ríos-Velásquez CM, Lacerda MVGD, Monteiro WM, Costa FTM, Amino R, Lopes SCP. Transmission-blocking compound candidates against Plasmodium vivax using P. berghei as an initial screening. Mem Inst Oswaldo Cruz 2021; 116:e200513. [PMID: 33566952 PMCID: PMC7874845 DOI: 10.1590/0074-02760200513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/04/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Different strategies for improvement of malaria control and elimination are based on the blockage of malaria parasite transmission to the mosquito vector. These strategies include the drugs that target the plasmodial sexual stages in humans and the early developmental stages inside mosquitoes. OBJECTIVES Here we tested Malaria Box compounds in order to evaluate their activity against male and female gametocytes in Plasmodium berghei, mosquito infection in P. vivax and ookinete formation in both species. METHODS/FINDINGS The membrane feeding assay and the development of ookinetes by a 24 h ex vivo culture and the ookinete yield per 1000 erythrocytes were used to test transmission-blocking potential of the Malaria Box compounds in P. vivax. For P. berghei we used flow cytometry to evaluate male and female gametocyte time course and fluorescence microscopy to check the ookinete development. The two species used in this study showed similar results concerning the compounds’ activity against gametocytes and ookinetes, which were different from those in P. falciparum. In addition, from the eight Malaria Box compounds tested in both species, compounds MMV665830, MMV665878 and MMV665941 were selected as a hit compounds due the high inhibition observed. CONCLUSION Our results showed that P. berghei is suitable as an initial screening system to test compounds against P. vivax.
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Affiliation(s)
- Camila Fabbri
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil.,Centro Universitário Fametro, Manaus, AM, Brasil
| | - Alexandre Oliveira Trindade
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil
| | - Francy's Sayara Andrade
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil
| | - Macejane Ferreira de Souza
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil
| | | | - Marcus Vinicius Guimarães de Lacerda
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil.,Fundação Oswaldo Cruz-Fiocruz, Instituto Leônidas e Maria Deane, Manaus, AM, Brasil
| | - Wuelton Marcelo Monteiro
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil
| | - Fabio Trindade Maranhão Costa
- Fundação Oswaldo Cruz-Fiocruz, Instituto Leônidas e Maria Deane, Manaus, AM, Brasil.,Universidade Estadual de Campinas, Campinas, SP, Brasil
| | - Rogerio Amino
- Institut Pasteur, Unit of Malaria Infection and Immunity, Department of Parasites and Insect Vectors, Paris, Île-de-France, France
| | - Stefanie Costa Pinto Lopes
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Instituto de Pesquisa Clínica Carlos Borborema, Manaus, AM, Brasil.,Universidade do Estado do Amazonas, Programa de Pós-Graduação em Medicina Tropical, Manaus, AM, Brasil.,Fundação Oswaldo Cruz-Fiocruz, Instituto Leônidas e Maria Deane, Manaus, AM, Brasil
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18
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Probing the B- & C-rings of the antimalarial tetrahydro-β-carboline MMV008138 for steric and conformational constraints. Bioorg Med Chem Lett 2020; 30:127520. [PMID: 32898696 DOI: 10.1016/j.bmcl.2020.127520] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/22/2020] [Indexed: 10/23/2022]
Abstract
The antimalarial candidate MMV008138 (1a) is of particular interest because its target enzyme (IspD) is absent in human. To achieve higher potency, and to probe for steric demand, a series of analogs of 1a were prepared that featured methyl-substitution of the B- and C-rings, as well as ring-chain transformations. X-ray crystallography, NMR spectroscopy and calculation were used to study the effects of these modifications on the conformation of the C-ring and orientation of the D-ring. Unfortunately, all the B- and C-ring analogs explored lost in vitro antimalarial activity. The possible role of steric effects and conformational changes on target engagement are discussed.
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19
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Metabolomics profiling reveals new aspects of dolichol biosynthesis in Plasmodium falciparum. Sci Rep 2020; 10:13264. [PMID: 32764679 PMCID: PMC7414040 DOI: 10.1038/s41598-020-70246-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/24/2020] [Indexed: 01/27/2023] Open
Abstract
The cis-polyisoprenoid lipids namely polyprenols, dolichols and their derivatives are linear polymers of several isoprene units. In eukaryotes, polyprenols and dolichols are synthesized as a mixture of four or more homologues of different length with one or two predominant species with sizes varying among organisms. Interestingly, co-occurrence of polyprenols and dolichols, i.e. detection of a dolichol along with significant levels of its precursor polyprenol, are unusual in eukaryotic cells. Our metabolomics studies revealed that cis-polyisoprenoids are more diverse in the malaria parasite Plasmodium falciparum than previously postulated as we uncovered active de novo biosynthesis and substantial levels of accumulation of polyprenols and dolichols of 15 to 19 isoprene units. A distinctive polyprenol and dolichol profile both within the intraerythrocytic asexual cycle and between asexual and gametocyte stages was observed suggesting that cis-polyisoprenoid biosynthesis changes throughout parasite’s development. Moreover, we confirmed the presence of an active cis-prenyltransferase (PfCPT) and that dolichol biosynthesis occurs via reduction of the polyprenol to dolichol by an active polyprenol reductase (PfPPRD) in the malaria parasite.
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20
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Florentin A, Cobb DW, Kudyba HM, Muralidharan V. Directing traffic: Chaperone-mediated protein transport in malaria parasites. Cell Microbiol 2020; 22:e13215. [PMID: 32388921 PMCID: PMC7282954 DOI: 10.1111/cmi.13215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/12/2020] [Accepted: 04/14/2020] [Indexed: 12/16/2022]
Abstract
The ability of eukaryotic parasites from the phylum Apicomplexa to cause devastating diseases is predicated upon their ability to maintain faithful and precise protein trafficking mechanisms. Their parasitic life cycle depends on the trafficking of effector proteins to the infected host cell, transport of proteins to several critical organelles required for survival, as well as transport of parasite and host proteins to the digestive organelles to generate the building blocks for parasite growth. Several recent studies have shed light on the molecular mechanisms parasites utilise to transform the infected host cells, transport proteins to essential metabolic organelles and for biogenesis of organelles required for continuation of their life cycle. Here, we review key pathways of protein transport originating and branching from the endoplasmic reticulum, focusing on the essential roles of chaperones in these processes. Further, we highlight key gaps in our knowledge that prevents us from building a holistic view of protein trafficking in these deadly human pathogens.
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Affiliation(s)
- Anat Florentin
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - David W Cobb
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Heather M Kudyba
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Vasant Muralidharan
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
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21
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Swift RP, Rajaram K, Liu HB, Dziedzic A, Jedlicka AE, Roberts AD, Matthews KA, Jhun H, Bumpus NN, Tewari SG, Wallqvist A, Prigge ST. A mevalonate bypass system facilitates elucidation of plastid biology in malaria parasites. PLoS Pathog 2020; 16:e1008316. [PMID: 32059044 PMCID: PMC7046295 DOI: 10.1371/journal.ppat.1008316] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 02/27/2020] [Accepted: 01/10/2020] [Indexed: 12/03/2022] Open
Abstract
Malaria parasites rely on a plastid organelle for survival during the blood stages of infection. However, the entire organelle is dispensable as long as the isoprenoid precursor, isopentenyl pyrophosphate (IPP), is supplemented in the culture medium. We engineered parasites to produce isoprenoid precursors from a mevalonate-dependent pathway, creating a parasite line that replicates normally after the loss of the apicoplast organelle. We show that carbon-labeled mevalonate is specifically incorporated into isoprenoid products, opening new avenues for researching this essential class of metabolites in malaria parasites. We also show that essential apicoplast proteins, such as the enzyme target of the drug fosmidomycin, can be deleted in this mevalonate bypass parasite line, providing a new method to determine the roles of other important apicoplast-resident proteins. Several antibacterial drugs kill malaria parasites by targeting basic processes, such as transcription, in the organelle. We used metabolomic and transcriptomic methods to characterize parasite metabolism after azithromycin treatment triggered loss of the apicoplast and found that parasite metabolism and the production of apicoplast proteins is largely unaltered. These results provide insight into the effects of apicoplast-disrupting drugs, several of which have been used to treat malaria infections in humans. Overall, the mevalonate bypass system provides a way to probe essential aspects of apicoplast biology and study the effects of drugs that target apicoplast processes. Malaria parasites rely on an organelle called the apicoplast for growth and survival. Antimalarial drugs such as azithromycin inhibit basic processes in the apicoplast and result in the disruption of the organelle. Surprisingly, addition of a single metabolite, isopentenyl pyrophosphate (IPP), allows the parasites to survive in culture after disruption of the apicoplast. Unfortunately, using IPP to study this phenomenon has several limitations: IPP is prohibitively expensive, has to be used at high concentrations, and has a half-life less than 5 hours. To address these problems, we engineered parasites to express four enzymes from an alternative pathway capable of producing IPP in the parasites. We validated this new system and used it to metabolically label essential metabolites, to delete an essential apicoplast protein, and to characterize the state of apicoplast-disrupted parasites. A key finding from these studies comes from transcriptomic and metabolomic analysis of parasites treated with the drug azithromycin. We found that apicoplast disruption results in few changes in parasite metabolism. In particular, the expression of hundreds of nuclear-encoded apicoplast proteins are not affected by disruption of the apicoplast organelle, making it likely that apicoplast metabolic pathways and processes are still functional in apicoplast-disrupted parasites.
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Affiliation(s)
- Russell P. Swift
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Krithika Rajaram
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Hans B. Liu
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Amanda Dziedzic
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Anne E. Jedlicka
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Aleah D. Roberts
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Krista A. Matthews
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Hugo Jhun
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Namandje N. Bumpus
- Department of Medicine (Division of Clinical Pharmacology), Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shivendra G. Tewari
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Ft. Detrick, Maryland, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, United States of America
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Ft. Detrick, Maryland, United States of America
| | - Sean T. Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
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22
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Valenciano AL, Fernández-Murga ML, Merino EF, Holderman NR, Butschek GJ, Shaffer KJ, Tyler PC, Cassera MB. Metabolic dependency of chorismate in Plasmodium falciparum suggests an alternative source for the ubiquinone biosynthesis precursor. Sci Rep 2019; 9:13936. [PMID: 31558748 PMCID: PMC6763611 DOI: 10.1038/s41598-019-50319-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 09/10/2019] [Indexed: 01/17/2023] Open
Abstract
The shikimate pathway, a metabolic pathway absent in humans, is responsible for the production of chorismate, a branch point metabolite. In the malaria parasite, chorismate is postulated to be a direct precursor in the synthesis of p-aminobenzoic acid (folate biosynthesis), p-hydroxybenzoic acid (ubiquinone biosynthesis), menaquinone, and aromatic amino acids. While the potential value of the shikimate pathway as a drug target is debatable, the metabolic dependency of chorismate in P. falciparum remains unclear. Current evidence suggests that the main role of chorismate is folate biosynthesis despite ubiquinone biosynthesis being active and essential in the malaria parasite. Our goal in the present work was to expand our knowledge of the ubiquinone head group biosynthesis and its potential metabolic dependency on chorismate in P. falciparum. We systematically assessed the development of both asexual and sexual stages of P. falciparum in a defined medium in the absence of an exogenous supply of chorismate end-products and present biochemical evidence suggesting that the benzoquinone ring of ubiquinones in this parasite may be synthesized through a yet unidentified route.
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Affiliation(s)
- Ana Lisa Valenciano
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States
| | - Maria L Fernández-Murga
- Laboratory of Experimental Pathology, Health Research Institute Hospital La Fe, Valencia, 46026, Spain
| | - Emilio F Merino
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States
| | - Nicole R Holderman
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States
| | - Grant J Butschek
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States
| | - Karl J Shaffer
- The Ferrier Research Institute, Victoria University of Wellington, Lower Hutt, New Zealand
| | - Peter C Tyler
- The Ferrier Research Institute, Victoria University of Wellington, Lower Hutt, New Zealand
| | - Maria Belen Cassera
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States.
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23
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Kennedy K, Crisafulli EM, Ralph SA. Delayed Death by Plastid Inhibition in Apicomplexan Parasites. Trends Parasitol 2019; 35:747-759. [PMID: 31427248 DOI: 10.1016/j.pt.2019.07.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 01/11/2023]
Abstract
The discovery of a plastid in apicomplexan parasites was hoped to be a watershed moment in the treatment of parasitic diseases as it revealed drug targets that are implicitly divergent from host molecular processes. Indeed, this organelle, known as the apicoplast, has since been a productive therapeutic target for pharmaceutical interventions against infections by Plasmodium, Toxoplasma, Babesia, and Theileria. However, some inhibitors of the apicoplast are restricted in their treatment utility because of their slow-kill kinetics, and this characteristic is called the delayed death effect. Here we review the recent genetic and pharmacological experiments that interrogate the causes of delayed death and explore the foundation of this phenomenon in Plasmodium and Toxoplasma parasites.
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Affiliation(s)
- Kit Kennedy
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Emily M Crisafulli
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia.
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Targeting the apicoplast in malaria. Biochem Soc Trans 2019; 47:973-983. [PMID: 31383817 DOI: 10.1042/bst20170563] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 05/22/2019] [Accepted: 06/10/2019] [Indexed: 12/25/2022]
Abstract
Malaria continues to be one of the leading causes of human mortality in the world, and the therapies available are insufficient for eradication. Severe malaria is caused by the apicomplexan parasite Plasmodium falciparum Apicomplexan parasites, including the Plasmodium spp., are descendants of photosynthetic algae, and therefore they possess an essential plastid organelle, named the apicoplast. Since humans and animals have no plastids, the apicoplast is an attractive target for drug development. Indeed, after its discovery, the apicoplast was found to host the target pathways of some known antimalarial drugs, which motivated efforts for further research into its biological functions and biogenesis. Initially, many apicoplast inhibitions were found to result in 'delayed death', whereby parasite killing is seen only at the end of one invasion-egress cycle. This slow action is not in line with the current standard for antimalarials, which seeded scepticism about the potential of compounds targeting apicoplast functions as good candidates for drug development. Intriguingly, recent evidence of apicoplast inhibitors causing rapid killing could put this organelle back in the spotlight. We provide an overview of drugs known to inhibit apicoplast pathways, alongside recent findings in apicoplast biology that may provide new avenues for drug development.
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25
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Biosca A, Dirscherl L, Moles E, Imperial S, Fernàndez-Busquets X. An ImmunoPEGliposome for Targeted Antimalarial Combination Therapy at the Nanoscale. Pharmaceutics 2019; 11:pharmaceutics11070341. [PMID: 31315185 PMCID: PMC6680488 DOI: 10.3390/pharmaceutics11070341] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/27/2019] [Accepted: 07/11/2019] [Indexed: 12/15/2022] Open
Abstract
Combination therapies, where two drugs acting through different mechanisms are administered simultaneously, are one of the most efficient approaches currently used to treat malaria infections. However, the different pharmacokinetic profiles often exhibited by the combined drugs tend to decrease treatment efficacy as the compounds are usually eliminated from the circulation at different rates. To circumvent this obstacle, we have engineered an immunoliposomal nanovector encapsulating hydrophilic and lipophilic compounds in its lumen and lipid bilayer, respectively. The antimalarial domiphen bromide has been encapsulated in the liposome membrane with good efficiency, although its high IC50 of ca. 1 µM for living parasites complicates its use as immunoliposomal therapy due to erythrocyte agglutination. The conjugation of antibodies against glycophorin A targeted the nanocarriers to Plasmodium-infected red blood cells and to gametocytes, the sole malaria parasite stage responsible for the transmission from the human to the mosquito vector. The antimalarials pyronaridine and atovaquone, which block the development of gametocytes, have been co-encapsulated in glycophorin A-targeted immunoliposomes. The co-immunoliposomized drugs have activities significantly higher than their free forms when tested in in vitro Plasmodium falciparum cultures: Pyronaridine and atovaquone concentrations that, when encapsulated in immunoliposomes, resulted in a 50% inhibition of parasite growth had no effect on the viability of the pathogen when used as free drugs.
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Affiliation(s)
- Arnau Biosca
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, ES-08036 Barcelona, Spain
- Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, ES-08028 Barcelona, Spain
- Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
| | - Lorin Dirscherl
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, ES-08036 Barcelona, Spain
- Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, ES-08028 Barcelona, Spain
- Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
| | - Ernest Moles
- Children's Cancer Institute, Lowy Cancer Research Centre, UNSW Sydney, PO Box 81, Randwick, NSW 2031, Australia
- School of Women's and Children's Health, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Santiago Imperial
- Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Avda. Diagonal 643, ES-08028 Barcelona, Spain
| | - Xavier Fernàndez-Busquets
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, ES-08036 Barcelona, Spain.
- Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, ES-08028 Barcelona, Spain.
- Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain.
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26
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van der Watt ME, Reader J, Churchyard A, Nondaba SH, Lauterbach SB, Niemand J, Abayomi S, van Biljon RA, Connacher JI, van Wyk RDJ, Le Manach C, Paquet T, González Cabrera D, Brunschwig C, Theron A, Lozano-Arias S, Rodrigues JFI, Herreros E, Leroy D, Duffy J, Street LJ, Chibale K, Mancama D, Coetzer TL, Birkholtz LM. Potent Plasmodium falciparum gametocytocidal compounds identified by exploring the kinase inhibitor chemical space for dual active antimalarials. J Antimicrob Chemother 2019; 73:1279-1290. [PMID: 29420756 DOI: 10.1093/jac/dky008] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 01/02/2018] [Indexed: 01/06/2023] Open
Abstract
Objectives Novel chemical tools to eliminate malaria should ideally target both the asexual parasites and transmissible gametocytes. Several imidazopyridazines (IMPs) and 2-aminopyridines (2-APs) have been described as potent antimalarial candidates targeting lipid kinases. However, these have not been extensively explored for stage-specific inhibition of gametocytes in Plasmodium falciparum parasites. Here we provide an in-depth evaluation of the gametocytocidal activity of compounds from these chemotypes and identify novel starting points for dual-acting antimalarials. Methods We evaluated compounds against P. falciparum gametocytes using several assay platforms for cross-validation and stringently identified hits that were further profiled for stage specificity, speed of action and ex vivo efficacy. Physicochemical feature extraction and chemogenomic fingerprinting were applied to explore the kinase inhibition susceptibility profile. Results We identified 34 compounds with submicromolar activity against late stage gametocytes, validated across several assay platforms. Of these, 12 were potent at <100 nM (8 were IMPs and 4 were 2-APs) and were also active against early stage gametocytes and asexual parasites, with >1000-fold selectivity towards the parasite over mammalian cells. Front-runner compounds targeted mature gametocytes within 48 h and blocked transmission to mosquitoes. The resultant chemogenomic fingerprint of parasites treated with the lead compounds revealed the importance of targeting kinases in asexual parasites and gametocytes. Conclusions This study encompasses an in-depth evaluation of the kinase inhibitor space for gametocytocidal activity. Potent lead compounds have enticing dual activities and highlight the importance of targeting the kinase superfamily in malaria elimination strategies.
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Affiliation(s)
- Mariëtte E van der Watt
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
| | - Janette Reader
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
| | - Alisje Churchyard
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Sindisiwe H Nondaba
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
| | - Sonja B Lauterbach
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Jandeli Niemand
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
| | - Sijuade Abayomi
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
| | - Riëtte A van Biljon
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
| | - Jessica I Connacher
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
| | - Roelof D J van Wyk
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
| | - Claire Le Manach
- Drug Discovery and Development Centre (H3D), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Tanya Paquet
- Drug Discovery and Development Centre (H3D), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Diego González Cabrera
- Drug Discovery and Development Centre (H3D), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Christel Brunschwig
- Drug Discovery and Development Centre (H3D), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Anjo Theron
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria 0001, South Africa
| | - Sonia Lozano-Arias
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Severo Ochoa, 2, 28760 Tres Cantos, Madrid, Spain
| | - Janneth F I Rodrigues
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Severo Ochoa, 2, 28760 Tres Cantos, Madrid, Spain
| | - Esperanza Herreros
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Severo Ochoa, 2, 28760 Tres Cantos, Madrid, Spain
| | - Didier Leroy
- Medicines for Malaria Venture, International Center Cointrin, Route de Pré-Bois 20, 1215, Geneva, Switzerland
| | - James Duffy
- Medicines for Malaria Venture, International Center Cointrin, Route de Pré-Bois 20, 1215, Geneva, Switzerland
| | - Leslie J Street
- Drug Discovery and Development Centre (H3D), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Kelly Chibale
- Drug Discovery and Development Centre (H3D), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.,South African Medical Research Council, Drug Discovery and Development Research Unit, Department of Chemistry and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | - Dalu Mancama
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria 0001, South Africa
| | - Theresa L Coetzer
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Lyn-Marie Birkholtz
- Department of Biochemistry, Institute for Sustainable Malaria Control and South African Medical Research Council Collaborating Centre for Malaria Research, University of Pretoria, Private Bag x20, Hatfield, Pretoria 0028, South Africa
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Cagašová K, Ghavami M, Yao ZK, Carlier PR. Questioning the γ-gauche effect: stereoassignment of 1,3-disubstituted-tetrahydro-β-carbolines using 1H- 1H coupling constants. Org Biomol Chem 2019; 17:6687-6698. [PMID: 31232413 DOI: 10.1039/c9ob01139k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The Pictet-Spengler reaction of tryptophan esters and aldehydes has been widely applied in natural product synthesis and medicinal chemistry. To date, the trans- or cis-configuration of 1,3-disubstituted tetrahydro-β-carbolines (THβCs) formed in this reaction has most often been assigned based on the relative 13C chemical shifts of C1 and C3 in the diastereomers. Although the upfield shifts of C1 and C3 in trans-THβCs relative to cis-THβCs has been attributed to steric compression associated with the "γ-gauche" effect, we show that this effect is not borne out experimentally for other carbons that should suffer this same compression. Thus we developed a robust alternative method for stereochemical assignment based on 1H NMR coupling constants (31 examples) and supported by extensive DFT-based conformational analysis and calculation of 1H-1H coupling constants. DFT calculations of 13C NMR chemical shifts also cast doubt upon the role of the "γ-gauche" effect on C1 and C3 chemical shifts in trans-THβCs.
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Affiliation(s)
- Kristýna Cagašová
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Hahn Hall South, 800 West Campus Drive, Blacksburg, Virginia 24061, USA.
| | - Maryam Ghavami
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Hahn Hall South, 800 West Campus Drive, Blacksburg, Virginia 24061, USA.
| | - Zhong-Ke Yao
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Hahn Hall South, 800 West Campus Drive, Blacksburg, Virginia 24061, USA.
| | - Paul R Carlier
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Hahn Hall South, 800 West Campus Drive, Blacksburg, Virginia 24061, USA.
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28
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Screening the Pathogen Box for Identification of New Chemical Agents with Anti- Fasciola hepatica Activity. Antimicrob Agents Chemother 2019; 63:AAC.02373-18. [PMID: 30602522 DOI: 10.1128/aac.02373-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 12/17/2018] [Indexed: 12/12/2022] Open
Abstract
Fascioliasis is an infectious parasitic disease distributed globally and caused by the liver fluke Fasciola hepatica or F. gigantica This neglected tropical disease affects both animals and humans, and it represents a latent public health problem due to the significant economic losses related to its effects on animal husbandry. For decades, triclabendazole has been the unique anti-Fasciola drug that can effectively treat this disease. However, triclabendazole resistance in fascioliasis has more recently been reported around the world, and thus, the discovery of novel drugs is an urgent need. The aim of this study was to investigate the fasciocidal properties of 400 compounds contained in the Pathogen Box. The first stage of the screening was carried out by measuring the fasciocidal activity on metacercariae at a concentration of 33 μM each compound (the standard dose). Subsequently, the activities of the most active compounds (n = 33) at their 50% inhibitory concentration (IC50) values against metacercariae were assayed, and the results showed that 13 compounds had IC50s of ≤10 μM. The second stage queried the activities of these compounds at 33 μM against adult flukes, with seven of the compounds producing high mortality rates of >50%. Four hit compounds were selected on the basis of their predicted nontoxic properties, and the IC50 values obtained for adult worms were <10 μM; thus, these compounds represented the best fasciocidal compounds tested here. A cytotoxicity assay on four types of cell lines demonstrated that three compounds were nontoxic at their most active concentration. In conclusion, three hit compounds identified in this proof-of-concept study are potential candidates in the discovery of new fasciocidal drugs. Further studies are warranted.
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29
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Gorki V, Singh R, Walter NS, Bagai U, Salunke DB. Synthesis and Evaluation of Antiplasmodial Efficacy of β-Carboline Derivatives against Murine Malaria. ACS OMEGA 2018; 3:13200-13210. [PMID: 30411030 PMCID: PMC6217594 DOI: 10.1021/acsomega.8b01833] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/28/2018] [Indexed: 05/26/2023]
Abstract
The difficulty of developing an efficient malaria vaccine along with increasing spread of multidrug resistant strain of Plasmodium falciparum to the available antimalarial drugs poses the need to discover safe and efficacious antimalarial drugs to control malaria. An alternative strategy is to synthesize compounds possessing structures similar to the active natural products or marketed drugs. Several biologically active natural products and drugs contain β-carboline moiety. In the present study, few selected β-carboline derivatives have been synthesized and tested for their in vitro and in vivo antiplasmodial activity against the rodent malaria parasite Plasmodium berghei (NK-65). The designed analogs exhibited considerable in vitro antimalarial activity. Two compounds (1R,3S)-methyl 1-(benzo[d][1,3]dioxol-5-yl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylate (9a) and (1R,3S)-methyl 1-(pyridin-3-yl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylate (9b) were further selected for in vivo studies. Both the lead compounds (9a and 9b) were observed to be safe for oral administration. The therapeutic effective dose (ED50) for 9a and 9b were determined and in the animal model, 9a (at 50 mg/kg dose) exhibited better activity in terms of parasite clearance and enhancement of host survival. Biochemical investigations also point toward the safety of the compound to the hepatic and renal functions of the rodent host. Further studies are underway to explore its activity alone as well as in combination therapy with artesunate against the human malaria parasite P. falciparum.
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Affiliation(s)
- Varun Gorki
- Parasitology
Laboratory, Department of Zoology, and Department of Chemistry and Centre
of Advanced Studies in Chemistry, Panjab
University, Chandigarh 160014, India
| | - Rahul Singh
- Parasitology
Laboratory, Department of Zoology, and Department of Chemistry and Centre
of Advanced Studies in Chemistry, Panjab
University, Chandigarh 160014, India
| | - Neha Sylvia Walter
- Parasitology
Laboratory, Department of Zoology, and Department of Chemistry and Centre
of Advanced Studies in Chemistry, Panjab
University, Chandigarh 160014, India
| | - Upma Bagai
- Parasitology
Laboratory, Department of Zoology, and Department of Chemistry and Centre
of Advanced Studies in Chemistry, Panjab
University, Chandigarh 160014, India
| | - Deepak B. Salunke
- Parasitology
Laboratory, Department of Zoology, and Department of Chemistry and Centre
of Advanced Studies in Chemistry, Panjab
University, Chandigarh 160014, India
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30
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Rajendran V, Singh C, Ghosh PC. Improved efficacy of doxycycline in liposomes against Plasmodium falciparum in culture and Plasmodium berghei infection in mice. Can J Physiol Pharmacol 2018; 96:1145-1152. [PMID: 30075085 DOI: 10.1139/cjpp-2018-0067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The rate at which Plasmodium falciparum is developing resistance to clinically used antimalarial drugs is alarming. Therefore, there is a compelling need to develop an efficient drug delivery system to improve the efficacy of existing antimalarial agents and circumvent drug resistance. Here, we report the antibacterial drug doxycycline (DOXY) in liposomal formulations exhibits enhanced antiplasmodial activity against blood stage forms of P. falciparum (3D7) in culture and established Plasmodium berghei NK-65 infection in murine model. Parasite killing on blood stage forms in culture was determined by a radiolabeled [3H] hypoxanthine incorporation assay and infected erythrocytes stained with Giemsa were counted using microscopy in vivo. The 50% inhibitory concentration (IC50) of DOXY-stearylamine liposome (IC50 0.36 μM) and DOXY-SPC:Chol-liposome (IC50 0.85 μM) exhibited marked growth inhibition of parasites compared with free DOXY (IC50 14 μM), with minimal toxicity to normal erythrocytes. Administration of polyethylene glycol distearoyl phosphatidylethanolamine-methoxy-polyethylene glycol2000 (DSPE-mPEG-2000) coated liposomes loaded with DOXY at 2.5 mg/kg per day resulted in efficacious killing of blood parasites with improved survival in mice relative to the free drug in both chloroquine sensitive and resistant strains of P. berghei infection. This is the first report to demonstrate that DOXY in liposomal system has immense chemotherapeutic potential against plasmodial infections at lower dosages.
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Affiliation(s)
- Vinoth Rajendran
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India.,Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Chanchal Singh
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India.,Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Prahlad C Ghosh
- Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India.,Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
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31
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Bartee D, Wheadon MJ, Freel Meyers CL. Synthesis and Evaluation of Fluoroalkyl Phosphonyl Analogues of 2- C-Methylerythritol Phosphate as Substrates and Inhibitors of IspD from Human Pathogens. J Org Chem 2018; 83:9580-9591. [PMID: 29870251 DOI: 10.1021/acs.joc.8b00686] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Targeting essential bacterial processes beyond cell wall, protein, nucleotide, and folate syntheses holds promise to reveal new antimicrobial agents and expand the potential drugs available for combination therapies. The synthesis of isoprenoid precursors, isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP), is vital for all organisms; however, humans use the mevalonate pathway for production of IDP/DMADP while many pathogens, including Plasmodium falciparum and Mycobacterium tuberculosis, use the orthogonal methylerythritol phosphate (MEP) pathway. Toward developing novel antimicrobial agents, we have designed and synthesized a series of phosphonyl analogues of MEP and evaluated their abilities to interact with IspD, both as inhibitors of the natural reaction and as antimetabolite alternative substrates that could be processed enzymatically to form stable phosphonyl analogues as potential inhibitors of downstream MEP pathway intermediates. In this compound series, the S-monofluoro MEP analogue displays the most potent inhibitory activity against Escherichia coli IspD and is the best substrate for both the E. coli and P. falciparum IspD orthologues with a Km approaching that of the natural substrate for the E. coli enzyme. This work represents a first step toward the development of phosphonyl MEP antimetabolites to modulate early isoprenoid biosynthesis in human pathogens.
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Affiliation(s)
- David Bartee
- Department of Pharmacology and Molecular Sciences , The Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
| | - Michael J Wheadon
- Department of Pharmacology and Molecular Sciences , The Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences , The Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
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32
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Ghavami M, Merino EF, Yao ZK, Elahi R, Simpson ME, Fernández-Murga ML, Butler JH, Casasanta MA, Krai PM, Totrov MM, Slade DJ, Carlier PR, Cassera MB. Biological Studies and Target Engagement of the 2- C-Methyl-d-Erythritol 4-Phosphate Cytidylyltransferase (IspD)-Targeting Antimalarial Agent (1 R,3 S)-MMV008138 and Analogs. ACS Infect Dis 2018; 4:549-559. [PMID: 29072835 DOI: 10.1021/acsinfecdis.7b00159] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Malaria continues to be one of the deadliest diseases worldwide, and the emergence of drug resistance parasites is a constant threat. Plasmodium parasites utilize the methylerythritol phosphate (MEP) pathway to synthesize isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which are essential for parasite growth. Previously, we and others identified that the Malaria Box compound MMV008138 targets the apicoplast and that parasite growth inhibition by this compound can be reversed by supplementation of IPP. Further work has revealed that MMV008138 targets the enzyme 2- C-methyl-d-erythritol 4-phosphate cytidylyltransferase (IspD) in the MEP pathway, which converts MEP and cytidine triphosphate (CTP) to cytidinediphosphate methylerythritol (CDP-ME) and pyrophosphate. In this work, we sought to gain insight into the structure-activity relationships by probing the ability of MMV008138 analogs to inhibit PfIspD recombinant enzyme. Here, we report PfIspD inhibition data for fosmidomycin (FOS) and 19 previously disclosed analogs and report parasite growth and PfIspD inhibition data for 27 new analogs of MMV008138. In addition, we show that MMV008138 does not target the recently characterized human IspD, reinforcing MMV008138 as a prototype of a new class of species-selective IspD-targeting antimalarial agents.
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Affiliation(s)
- Maryam Ghavami
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Hahn Hall South, 800 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Emilio F. Merino
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Engel Hall, 340 West Campus Drive, Blacksburg, Virginia 24061, United States
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Zhong-Ke Yao
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Hahn Hall South, 800 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Rubayet Elahi
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Engel Hall, 340 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Morgan E. Simpson
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Engel Hall, 340 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Maria L. Fernández-Murga
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Engel Hall, 340 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Joshua H. Butler
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
| | - Michael A. Casasanta
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Engel Hall, 340 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Priscilla M. Krai
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Engel Hall, 340 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Maxim M. Totrov
- Molsoft LLC, 11199 Sorrento Valley Road, San Diego, California 92121, United States
| | - Daniel J. Slade
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Engel Hall, 340 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Paul R. Carlier
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Hahn Hall South, 800 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Maria Belen Cassera
- Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Engel Hall, 340 West Campus Drive, Blacksburg, Virginia 24061, United States
- Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, 120 Green Street, Athens, Georgia 30602, United States
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Vu H, Pedro L, Mak T, McCormick B, Rowley J, Liu M, Di Capua A, Williams-Noonan B, Pham NB, Pouwer R, Nguyen B, Andrews KT, Skinner-Adams T, Kim J, Hol WGJ, Hui R, Crowther GJ, Van Voorhis WC, Quinn RJ. Fragment-Based Screening of a Natural Product Library against 62 Potential Malaria Drug Targets Employing Native Mass Spectrometry. ACS Infect Dis 2018; 4:431-444. [PMID: 29436819 PMCID: PMC5902791 DOI: 10.1021/acsinfecdis.7b00197] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
Natural
products are well known for their biological relevance, high degree
of three-dimensionality, and access to areas of largely unexplored
chemical space. To shape our understanding of the interaction between
natural products and protein targets in the postgenomic era, we have
used native mass spectrometry to investigate 62 potential protein
targets for malaria using a natural-product-based fragment library.
We reveal here 96 low-molecular-weight natural products identified
as binding partners of 32 of the putative malarial targets. Seventy-nine
(79) fragments have direct growth inhibition on Plasmodium
falciparum at concentrations that are promising for the development
of fragment hits against these protein targets. This adds a fragment
library to the published HTS active libraries in the public domain.
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Affiliation(s)
- Hoan Vu
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Liliana Pedro
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Tin Mak
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Brendan McCormick
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Jessica Rowley
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Miaomiao Liu
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Angela Di Capua
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Billy Williams-Noonan
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Ngoc B. Pham
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Rebecca Pouwer
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Bao Nguyen
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Katherine T. Andrews
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | - Tina Skinner-Adams
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
| | | | | | - Raymond Hui
- Structural Genomics Consortium, University of Toronto, MaRS South Tower, seventh floor 101 College Street, Toronto, Ontario M5G 1L7, Canada
| | | | | | - Ronald J. Quinn
- Griffith Institute for Drug Discovery, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia
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Antimalarial agents against both sexual and asexual parasites stages: structure-activity relationships and biological studies of the Malaria Box compound 1-[5-(4-bromo-2-chlorophenyl)furan-2-yl]-N-[(piperidin-4-yl)methyl]methanamine (MMV019918) and analogues. Eur J Med Chem 2018; 150:698-718. [PMID: 29571157 DOI: 10.1016/j.ejmech.2018.03.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 03/06/2018] [Accepted: 03/08/2018] [Indexed: 01/31/2023]
Abstract
Therapies addressing multiple stages of Plasmodium falciparum life cycle are highly desirable for implementing malaria elimination strategies. MMV019918 (1, 1-[5-(4-bromo-2-chlorophenyl)furan-2-yl]-N-[(piperidin-4-yl)methyl]methanamine) was selected from the MMV Malaria Box for its dual activity against both asexual stages and gametocytes. In-depth structure-activity relationship studies and cytotoxicity evaluation led to the selection of 25 for further biological investigation. The potential transmission blocking activity of 25 versus P. falciparum was confirmed through the standard membrane-feeding assay. Both 1 and 25 significantly prolonged atrioventricular conduction time in Langendorff-isolated rat hearts, and showed inhibitory activity of Ba2+ current through Cav1.2 channels. An in silico target-fishing study suggested the enzyme phosphoethanolamine methyltransferase (PfPMT) as a potential target. However, compound activity against PfPMT did not track with the antiplasmodial activity, suggesting the latter activity relies on a different molecular target. Nevertheless, 25 showed interesting activity against PfPMT, which could be an important starting point for the identification of more potent inhibitors active against both sexual and asexual stages of the parasite.
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Discovery of New Inhibitors of Toxoplasma gondii via the Pathogen Box. Antimicrob Agents Chemother 2018; 62:AAC.01640-17. [PMID: 29133550 PMCID: PMC5786798 DOI: 10.1128/aac.01640-17] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/29/2017] [Indexed: 01/08/2023] Open
Abstract
Toxoplasma gondii is a cosmopolitan protozoan parasite which affects approximately 30% of the population worldwide. The drugs currently used against toxoplasmosis are few in number and show several limitations, such as drug intolerance, poor bioavailability, or drug resistance mechanism developed by the parasite. Thus, it is important to find new compounds able to inhibit parasite invasion or proliferation. In this study, the 400 compounds of the open-access Pathogen Box, provided by the Medicines for Malaria Venture (MMV) foundation, were screened for their anti-Toxoplasma gondii activity. A preliminary in vitro screening performed over 72 h by an enzyme-linked immunosorbent assay (ELISA) revealed 15 interesting compounds that were effective against T. gondii at 1 μM. Their cytotoxicity was estimated on Vero cells, and their 50% inhibitory concentrations (IC50) were further calculated. As a result, eight anti-Toxoplasma gondii compounds with an IC50 of less than 2 μM and a selectivity index (SI) value of greater than 4 were identified. The most active was MMV675968, showing an IC50 of 0.02 μM and a selectivity index value equal to 275. Two other compounds, MMV689480 and MMV687807, also showed a good activity against T. gondii, with IC50s of 0.10 μM (SI of 86.6) and 0.15 μM (SI of 11.3), respectively. Structure-activity relationships for the eight selected compounds also were discussed on the basis of fingerprinting similarity measurements using the Tanimoto method. The anti-Toxoplasma gondii compounds highlighted here represent potential candidates for the development of new drugs that could be used against toxoplasmosis.
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36
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Targeted Phenotypic Screening in Plasmodium falciparum and Toxoplasma gondii Reveals Novel Modes of Action of Medicines for Malaria Venture Malaria Box Molecules. mSphere 2018; 3:mSphere00534-17. [PMID: 29359192 PMCID: PMC5770543 DOI: 10.1128/msphere.00534-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 12/20/2017] [Indexed: 01/23/2023] Open
Abstract
The Malaria Box collection includes 400 chemically diverse small molecules with documented potency against malaria parasite growth, but the underlying modes of action are largely unknown. Using complementary phenotypic screens against Plasmodium falciparum and Toxoplasma gondii, we report phenotype-specific hits based on inhibition of overall parasite growth, apicoplast segregation, and egress or host invasion, providing hitherto unavailable insights into the possible mechanisms affected. First, the Malaria Box library was screened against tachyzoite stage T. gondii and the half-maximal effective concentrations (EC50s) of molecules showing ≥80% growth inhibition at 10 µM were determined. Comparison of the EC50s for T. gondii and P. falciparum identified a subset of 24 molecules with nanomolar potency against both parasites. Thirty molecules that failed to induce acute growth inhibition in T. gondii tachyzoites in a 2-day assay caused delayed parasite death upon extended exposure, with at least three molecules interfering with apicoplast segregation during daughter cell formation. Using flow cytometry and microscopy-based examinations, we prioritized 26 molecules with the potential to inhibit host cell egress/invasion during asexual developmental stages of P. falciparum. None of the inhibitors affected digestive vacuole integrity, ruling out a mechanism mediated by broadly specific protease inhibitor activity. Interestingly, five of the plasmodial egress inhibitors inhibited ionophore-induced egress of T. gondii tachyzoites. These findings highlight the advantage of comparative and targeted phenotypic screens in related species as a means to identify lead molecules with a conserved mode of action. Further work on target identification and mechanism analysis will facilitate the development of antiparasitic compounds with cross-species efficacy. IMPORTANCE The phylum Apicomplexa includes many human and animal pathogens, such as Plasmodium falciparum (human malaria) and Toxoplasma gondii (human and animal toxoplasmosis). Widespread resistance to current antimalarials and the lack of a commercial vaccine necessitate novel pharmacological interventions with distinct modes of action against malaria. For toxoplasmosis, new drugs to effectively eliminate tissue-dwelling latent cysts of the parasite are needed. The Malaria Box antimalarial collection, managed and distributed by the Medicines for Malaria Venture, includes molecules of novel chemical classes with proven antimalarial efficacy. Using targeted phenotypic assays of P. falciparum and T. gondii, we have identified a subset of the Malaria Box molecules as potent inhibitors of plastid segregation and parasite invasion and egress, thereby providing early insights into their probable mode of action. Five molecules that inhibit the egress of both parasites have been identified for further mechanistic studies. Thus, the approach we have used to identify novel molecules with defined modes of action in multiple parasites can expedite the development of pan-active antiparasitic agents.
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37
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Gisselberg JE, Herrera Z, Orchard LM, Llinás M, Yeh E. Specific Inhibition of the Bifunctional Farnesyl/Geranylgeranyl Diphosphate Synthase in Malaria Parasites via a New Small-Molecule Binding Site. Cell Chem Biol 2017; 25:185-193.e5. [PMID: 29276048 DOI: 10.1016/j.chembiol.2017.11.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/24/2017] [Accepted: 11/22/2017] [Indexed: 12/19/2022]
Abstract
The bifunctional farnesyl/geranylgeranyl diphosphate synthase (FPPS/GGPPS) is a key branchpoint enzyme in isoprenoid biosynthesis in Plasmodium falciparum (malaria) parasites. PfFPPS/GGPPS is a validated, high-priority antimalarial drug target. Unfortunately, current bisphosphonate drugs that inhibit FPPS and GGPPS enzymes by acting as a diphosphate substrate analog show poor bioavailability and selectivity for PfFPPS/GGPPS. We identified a new non-bisphosphonate compound, MMV019313, which is highly selective for PfFPPS/GGPPS and showed no activity against human FPPS or GGPPS. Inhibition of PfFPPS/GGPPS by MMV019313, but not bisphosphonates, was disrupted in an S228T variant, demonstrating that MMV019313 and bisphosphonates have distinct modes of inhibition. Molecular docking indicated that MMV019313 did not bind previously characterized substrate sites in PfFPPS/GGPPS. Our finding uncovers a new, selective small-molecule binding site in this important antimalarial drug target with superior druggability compared with the known inhibitor site and sets the stage for the development of Plasmodium-specific FPPS/GGPPS inhibitors.
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Affiliation(s)
- Jolyn E Gisselberg
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA
| | - Zachary Herrera
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA
| | - Lindsey M Orchard
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA; Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
| | - Manuel Llinás
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA; Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA; Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Ellen Yeh
- Department of Biochemistry, Stanford Medical School, Stanford University, Stanford, CA 94305, USA; Department of Pathology, Stanford Medical School, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford Medical School, Stanford University, Stanford, CA 94305, USA.
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38
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Validation of Putative Apicoplast-Targeting Drugs Using a Chemical Supplementation Assay in Cultured Human Malaria Parasites. Antimicrob Agents Chemother 2017; 62:AAC.01161-17. [PMID: 29109165 DOI: 10.1128/aac.01161-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/18/2017] [Indexed: 11/20/2022] Open
Abstract
Malaria parasites contain a relict plastid, the apicoplast, which is considered an excellent drug target due to its bacterial-like ancestry. Numerous parasiticidals have been proposed to target the apicoplast, but few have had their actual targets substantiated. Isopentenyl pyrophosphate (IPP) production is the sole required function of the apicoplast in the blood stage of the parasite life cycle, and IPP supplementation rescues parasites from apicoplast-perturbing drugs. Hence, any drug that kills parasites when IPP is supplied in culture must have a nonapicoplast target. Here, we use IPP supplementation to discriminate whether 23 purported apicoplast-targeting drugs are on- or off-target. We demonstrate that a prokaryotic DNA replication inhibitor (ciprofloxacin), several prokaryotic translation inhibitors (chloramphenicol, doxycycline, tetracycline, clindamycin, azithromycin, erythromycin, and clarithromycin), a tRNA synthase inhibitor (mupirocin), and two IPP synthesis pathway inhibitors (fosmidomycin and FR900098) have apicoplast targets. Intriguingly, fosmidomycin and FR900098 leave the apicoplast intact, whereas the others eventually result in apicoplast loss. Actinonin, an inhibitor of bacterial posttranslational modification, does not produce a typical delayed-death response but is rescued with IPP, thereby confirming its apicoplast target. Parasites treated with putative apicoplast fatty acid pathway inhibitors could not be rescued, demonstrating that these drugs have their primary targets outside the apicoplast, which agrees with the dispensability of the apicoplast fatty acid synthesis pathways in the blood stage of malaria parasites. IPP supplementation provides a simple test of whether a compound has a target in the apicoplast and can be used to screen novel compounds for mode of action.
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Florentin A, Cobb DW, Fishburn JD, Cipriano MJ, Kim PS, Fierro MA, Striepen B, Muralidharan V. PfClpC Is an Essential Clp Chaperone Required for Plastid Integrity and Clp Protease Stability in Plasmodium falciparum. Cell Rep 2017; 21:1746-1756. [PMID: 29141210 PMCID: PMC5726808 DOI: 10.1016/j.celrep.2017.10.081] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/17/2017] [Accepted: 10/21/2017] [Indexed: 01/11/2023] Open
Abstract
The deadly malaria parasite Plasmodium falciparum contains a nonphotosynthetic plastid, known as the apicoplast, that functions to produce essential metabolites, and drugs that target the apicoplast are clinically effective. Several prokaryotic caseinolytic protease (Clp) genes have been identified in the Plasmodium genome. Using phylogenetic analysis, we focused on the Clp members that may form a regulated proteolytic complex in the apicoplast. We genetically targeted members of this complex and generated conditional mutants of the apicoplast-localized PfClpC chaperone and PfClpP protease. Conditional inhibition of the PfClpC chaperone resulted in growth arrest and apicoplast loss and was rescued by addition of the essential apicoplast-derived metabolite IPP. Using a double-conditional mutant parasite line, we discovered that the chaperone activity is required to stabilize the mature protease, revealing functional interactions. These data demonstrate the essential function of PfClpC in maintaining apicoplast integrity and its role in regulating the proteolytic activity of the Clp complex.
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Affiliation(s)
- Anat Florentin
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - David W Cobb
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Jillian D Fishburn
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Michael J Cipriano
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Paul S Kim
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Manuel A Fierro
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Boris Striepen
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Vasant Muralidharan
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
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40
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Screening the Medicines for Malaria Venture Pathogen Box across Multiple Pathogens Reclassifies Starting Points for Open-Source Drug Discovery. Antimicrob Agents Chemother 2017; 61:AAC.00379-17. [PMID: 28674055 PMCID: PMC5571359 DOI: 10.1128/aac.00379-17] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/19/2017] [Indexed: 01/19/2023] Open
Abstract
Open-access drug discovery provides a substantial resource for diseases primarily affecting the poor and disadvantaged. The open-access Pathogen Box collection is comprised of compounds with demonstrated biological activity against specific pathogenic organisms. The supply of this resource by the Medicines for Malaria Venture has the potential to provide new chemical starting points for a number of tropical and neglected diseases, through repurposing of these compounds for use in drug discovery campaigns for these additional pathogens. We tested the Pathogen Box against kinetoplastid parasites and malaria life cycle stages in vitro Consequently, chemical starting points for malaria, human African trypanosomiasis, Chagas disease, and leishmaniasis drug discovery efforts have been identified. Inclusive of this in vitro biological evaluation, outcomes from extensive literature reviews and database searches are provided. This information encompasses commercial availability, literature reference citations, other aliases and ChEMBL number with associated biological activity, where available. The release of this new data for the Pathogen Box collection into the public domain will aid the open-source model of drug discovery. Importantly, this will provide novel chemical starting points for drug discovery and target identification in tropical disease research.
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41
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Edwards RL, Brothers RC, Wang X, Maron MI, Ziniel PD, Tsang PS, Kraft TE, Hruz PW, Williamson KC, Dowd CS, John ARO. MEPicides: potent antimalarial prodrugs targeting isoprenoid biosynthesis. Sci Rep 2017; 7:8400. [PMID: 28827774 PMCID: PMC5567135 DOI: 10.1038/s41598-017-07159-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 06/21/2017] [Indexed: 01/29/2023] Open
Abstract
The emergence of Plasmodium falciparum resistant to frontline therapeutics has prompted efforts to identify and validate agents with novel mechanisms of action. MEPicides represent a new class of antimalarials that inhibit enzymes of the methylerythritol phosphate (MEP) pathway of isoprenoid biosynthesis, including the clinically validated target, deoxyxylulose phosphate reductoisomerase (Dxr). Here we describe RCB-185, a lipophilic prodrug with nanomolar activity against asexual parasites. Growth of P. falciparum treated with RCB-185 was rescued by isoprenoid precursor supplementation, and treatment substantially reduced metabolite levels downstream of the Dxr enzyme. In addition, parasites that produced higher levels of the Dxr substrate were resistant to RCB-185. Notably, environmental isolates resistant to current therapies remained sensitive to RCB-185, the compound effectively treated sexually-committed parasites, and was both safe and efficacious in malaria-infected mice. Collectively, our data demonstrate that RCB-185 potently and selectively inhibits Dxr in P. falciparum, and represents a promising lead compound for further drug development.
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Affiliation(s)
- Rachel L Edwards
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Robert C Brothers
- Department of Chemistry, George Washington University, Washington, DC, USA
| | - Xu Wang
- Department of Chemistry, George Washington University, Washington, DC, USA
| | - Maxim I Maron
- Department of Biology, Loyola University Chicago, Chicago, IL, USA
- Albert Einstein College of Medicine, Bronx, New York, USA
| | - Peter D Ziniel
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Patricia S Tsang
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, NIAID, NIH, Bethesda, MD, USA
| | - Thomas E Kraft
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
- Roche Pharma Research and Early Development, Roche Innovation Center, Munich, Nonnenwald, Penzberg, Germany
| | - Paul W Hruz
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kim C Williamson
- Department of Biology, Loyola University Chicago, Chicago, IL, USA
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Cynthia S Dowd
- Department of Chemistry, George Washington University, Washington, DC, USA
| | - Audrey R Odom John
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
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42
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Vanaerschot M, Lucantoni L, Li T, Combrinck JM, Ruecker A, Kumar TRS, Rubiano K, Ferreira PE, Siciliano G, Gulati S, Henrich PP, Ng CL, Murithi JM, Corey VC, Duffy S, Lieberman OJ, Veiga MI, Sinden RE, Alano P, Delves MJ, Lee Sim K, Winzeler EA, Egan TJ, Hoffman SL, Avery VM, Fidock DA. Hexahydroquinolines are antimalarial candidates with potent blood-stage and transmission-blocking activity. Nat Microbiol 2017. [PMID: 28808258 DOI: 10.1038/s41564-017-0007–4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Antimalarial compounds with dual therapeutic and transmission-blocking activity are desired as high-value partners for combination therapies. Here, we report the identification and characterization of hexahydroquinolines (HHQs) that show low nanomolar potency against both pathogenic and transmissible intra-erythrocytic forms of the malaria parasite Plasmodium falciparum. This activity translates into potent transmission-blocking potential, as shown by in vitro male gamete formation assays and reduced oocyst infection and prevalence in Anopheles mosquitoes. In vivo studies illustrated the ability of lead HHQs to suppress Plasmodium berghei blood-stage parasite proliferation. Resistance selection studies, confirmed by CRISPR-Cas9-based gene editing, identified the digestive vacuole membrane-spanning transporter PfMDR1 (P. falciparum multidrug resistance gene-1) as a determinant of parasite resistance to HHQs. Haemoglobin and haem fractionation assays suggest a mode of action that results in reduced haemozoin levels and might involve inhibition of host haemoglobin uptake into intra-erythrocytic parasites. Furthermore, parasites resistant to HHQs displayed increased susceptibility to several first-line antimalarial drugs, including lumefantrine, confirming that HHQs have a different mode of action to other antimalarials drugs for which PfMDR1 is known to confer resistance. This work evokes therapeutic strategies that combine opposing selective pressures on this parasite transporter as an approach to countering the emergence and transmission of multidrug-resistant P. falciparum malaria.
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Affiliation(s)
- Manu Vanaerschot
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Leonardo Lucantoni
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, 4111, Queensland, Australia
| | - Tao Li
- Sanaria Inc., Rockville, MD, 20852, USA
| | - Jill M Combrinck
- Division of Pharmacology, Department of Medicine, University of Cape Town, Cape Town, 7925, South Africa
| | - Andrea Ruecker
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - T R Santha Kumar
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Kelly Rubiano
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Pedro E Ferreira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
| | - Giulia Siciliano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Sonia Gulati
- 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
| | - Caroline L Ng
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - James M Murithi
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Victoria C Corey
- University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Sandra Duffy
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, 4111, Queensland, Australia
| | - Ori J Lieberman
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - M Isabel Veiga
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
| | - Robert E Sinden
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Michael J Delves
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | | | - Elizabeth A Winzeler
- University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Timothy J Egan
- Department of Chemistry, University of Cape Town, Cape Town, 7700, South Africa
| | | | - Vicky M Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, 4111, Queensland, Australia
| | - 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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43
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Vanaerschot M, Lucantoni L, Li T, Combrinck JM, Ruecker A, Kumar TRS, Rubiano K, Ferreira PE, Siciliano G, Gulati S, Henrich PP, Ng CL, Murithi JM, Corey VC, Duffy S, Lieberman OJ, Veiga MI, Sinden RE, Alano P, Delves MJ, Lee Sim K, Winzeler EA, Egan TJ, Hoffman SL, Avery VM, Fidock DA. Hexahydroquinolines are antimalarial candidates with potent blood-stage and transmission-blocking activity. Nat Microbiol 2017; 2:1403-1414. [PMID: 28808258 DOI: 10.1038/s41564-017-0007-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 07/11/2017] [Indexed: 12/21/2022]
Abstract
Antimalarial compounds with dual therapeutic and transmission-blocking activity are desired as high-value partners for combination therapies. Here, we report the identification and characterization of hexahydroquinolines (HHQs) that show low nanomolar potency against both pathogenic and transmissible intra-erythrocytic forms of the malaria parasite Plasmodium falciparum. This activity translates into potent transmission-blocking potential, as shown by in vitro male gamete formation assays and reduced oocyst infection and prevalence in Anopheles mosquitoes. In vivo studies illustrated the ability of lead HHQs to suppress Plasmodium berghei blood-stage parasite proliferation. Resistance selection studies, confirmed by CRISPR-Cas9-based gene editing, identified the digestive vacuole membrane-spanning transporter PfMDR1 (P. falciparum multidrug resistance gene-1) as a determinant of parasite resistance to HHQs. Haemoglobin and haem fractionation assays suggest a mode of action that results in reduced haemozoin levels and might involve inhibition of host haemoglobin uptake into intra-erythrocytic parasites. Furthermore, parasites resistant to HHQs displayed increased susceptibility to several first-line antimalarial drugs, including lumefantrine, confirming that HHQs have a different mode of action to other antimalarials drugs for which PfMDR1 is known to confer resistance. This work evokes therapeutic strategies that combine opposing selective pressures on this parasite transporter as an approach to countering the emergence and transmission of multidrug-resistant P. falciparum malaria.
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Affiliation(s)
- Manu Vanaerschot
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Leonardo Lucantoni
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, 4111, Queensland, Australia
| | - Tao Li
- Sanaria Inc., Rockville, MD, 20852, USA
| | - Jill M Combrinck
- Division of Pharmacology, Department of Medicine, University of Cape Town, Cape Town, 7925, South Africa
| | - Andrea Ruecker
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - T R Santha Kumar
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Kelly Rubiano
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Pedro E Ferreira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
| | - Giulia Siciliano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Sonia Gulati
- 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
| | - Caroline L Ng
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - James M Murithi
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Victoria C Corey
- University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Sandra Duffy
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, 4111, Queensland, Australia
| | - Ori J Lieberman
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, 10032, USA
| | - M Isabel Veiga
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
| | - Robert E Sinden
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, 00161, Rome, Italy
| | - Michael J Delves
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | | | - Elizabeth A Winzeler
- University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Timothy J Egan
- Department of Chemistry, University of Cape Town, Cape Town, 7700, South Africa
| | | | - Vicky M Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, 4111, Queensland, Australia
| | - 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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44
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The need to compare: assessing the level of agreement of three high-throughput assays against Plasmodium falciparum mature gametocytes. Sci Rep 2017; 7:45992. [PMID: 28378767 PMCID: PMC5380998 DOI: 10.1038/srep45992] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/07/2017] [Indexed: 12/22/2022] Open
Abstract
Whole-cell High-Throughput Screening (HTS) is a key tool for the discovery of much needed malaria transmission blocking drugs. Discrepancies in the reported outcomes from various HTS Plasmodium falciparum gametocytocidal assays hinder the direct comparison of data and ultimately the interpretation of the transmission blocking potential of hits. To dissect the underlying determinants of such discrepancies and assess the impact that assay-specific factors have on transmission-blocking predictivity, a 39-compound subset from the Medicines for Malaria Venture Malaria Box was tested in parallel against three distinct mature stage gametocytocidal assays, under strictly controlled parasitological, chemical, temporal and analytical conditions resembling the standard membrane feeding assay (SMFA). Apart from a few assay-specific outliers, which highlighted the value of utilizing multiple complementary approaches, good agreement was observed (average ΔpIC50 of 0.12 ± 0.01). Longer compound incubation times improved the ability of the least sensitive assay to detect actives by 2-fold. Finally, combining the number of actives identified by any single assay with those obtained at longer incubation times yielded greatly improved outcomes and agreement with SMFA. Screening compounds using extended incubation times and using multiple in vitro assay technologies are valid approaches for the efficient identification of biologically relevant malaria transmission blocking hits.
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45
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Price KE, Armstrong CM, Imlay LS, Hodge DM, Pidathala C, Roberts NJ, Park J, Mikati M, Sharma R, Lawrenson AS, Tolia NH, Berry NG, O'Neill PM, John ARO. Molecular Mechanism of Action of Antimalarial Benzoisothiazolones: Species-Selective Inhibitors of the Plasmodium spp. MEP Pathway enzyme, IspD. Sci Rep 2016; 6:36777. [PMID: 27857147 PMCID: PMC5114681 DOI: 10.1038/srep36777] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/20/2016] [Indexed: 01/10/2023] Open
Abstract
The methylerythritol phosphate (MEP) pathway is an essential metabolic pathway found in malaria parasites, but absent in mammals, making it a highly attractive target for the discovery of novel and selective antimalarial therapies. Using high-throughput screening, we have identified 2-phenyl benzo[d]isothiazol-3(2H)-ones as species-selective inhibitors of Plasmodium spp. 2-C-methyl-D-erythritol-4-phosphate cytidyltransferase (IspD), the third catalytic enzyme of the MEP pathway. 2-Phenyl benzo[d]isothiazol-3(2H)-ones display nanomolar inhibitory activity against P. falciparum and P. vivax IspD and prevent the growth of P. falciparum in culture, with EC50 values below 400 nM. In silico modeling, along with enzymatic, genetic and crystallographic studies, have established a mechanism-of-action involving initial non-covalent recognition of inhibitors at the IspD binding site, followed by disulfide bond formation through attack of an active site cysteine residue on the benzo[d]isothiazol-3(2H)-one core. The species-selective inhibitory activity of these small molecules against Plasmodium spp. IspD and cultured parasites suggests they have potential as lead compounds in the pursuit of novel drugs to treat malaria.
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Affiliation(s)
- Kathryn E Price
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Christopher M Armstrong
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Leah S Imlay
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Dana M Hodge
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - C Pidathala
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Natalie J Roberts
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Jooyoung Park
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marwa Mikati
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Raman Sharma
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | | | - Niraj H Tolia
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Neil G Berry
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Paul M O'Neill
- Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Audrey R Odom John
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA.,Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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46
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Fletcher S, Lucantoni L, Sykes ML, Jones AJ, Holleran JP, Saliba KJ, Avery VM. Biological characterization of chemically diverse compounds targeting the Plasmodium falciparum coenzyme A synthesis pathway. Parasit Vectors 2016; 9:589. [PMID: 27855724 PMCID: PMC5114727 DOI: 10.1186/s13071-016-1860-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/27/2016] [Indexed: 01/10/2023] Open
Abstract
Background In the fight against malaria, the discovery of chemical compounds with a novel mode of action and/or chemistry distinct from currently used drugs is vital to counteract the parasite’s known ability to develop drug resistance. Another desirable aspect is efficacy against gametocytes, the sexual developmental stage of the parasite which enables the transmission through Anopheles vectors. Using a chemical rescue approach, we previously identified compounds targeting Plasmodium falciparum coenzyme A (CoA) synthesis or utilization, a promising target that has not yet been exploited in anti-malarial drug development. Results We report on the outcomes of a series of biological tests that help to define the species- and stage-specificity, as well as the potential targets of these chemically diverse compounds. Compound activity against P. falciparum gametocytes was determined to assess stage-specificity and transmission-reducing potential. Against early stage gametocytes IC50 values ranging between 60 nM and 7.5 μM were obtained. With the exception of two compounds with sub-micromolar potencies across all intra-erythrocytic stages, activity against late stage gametocytes was lower. None of the compounds were specific pantothenate kinase inhibitors. Chemical rescue profiling with CoA pathway intermediates demonstrated that most compounds acted on either of the two final P. falciparum CoA synthesis enzymes, phosphopantetheine adenylyltransferase (PPAT) or dephospho CoA kinase (DPCK). The most active compound targeted either phosphopantothenoylcysteine synthetase (PPCS) or phosphopantothenoylcysteine decarboxylase (PPCDC). Species-specificity was evaluated against Trypanosoma cruzi and Trypanosoma brucei brucei. No specific activity against T. cruzi amastigotes was observed; however three compounds inhibited the viability of trypomastigotes with sub-micromolar potencies and were confirmed to act on T. b. brucei CoA synthesis. Conclusions Utilizing the compounds we previously identified as effective against asexual P. falciparum, we demonstrate for the first time that gametocytes, like the asexual stages, depend on CoA, with two compounds exhibiting sub-micromolar potencies across asexual forms and all gametocytes stages tested. Furthermore, three compounds inhibited the viability of T. cruzi and T. b. brucei trypomastigotes with sub-micromolar potencies and were confirmed to act on T. b. brucei CoA synthesis, indicating that the CoA synthesis pathway might represent a valuable new drug target in these parasite species. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1860-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sabine Fletcher
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Leonardo Lucantoni
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Melissa L Sykes
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Amy J Jones
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - John P Holleran
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Kevin J Saliba
- Medical School and Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Vicky M Avery
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia.
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47
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Magistrado PA, Corey VC, Lukens AK, LaMonte G, Sasaki E, Meister S, Wree M, Winzeler E, Wirth DF. Plasmodium falciparum Cyclic Amine Resistance Locus (PfCARL), a Resistance Mechanism for Two Distinct Compound Classes. ACS Infect Dis 2016; 2:816-826. [PMID: 27933786 PMCID: PMC5109296 DOI: 10.1021/acsinfecdis.6b00025] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
![]()
MMV007564
is a novel antimalarial benzimidazolyl piperidine chemotype
identified in cellular screens. To identify the genetic determinant
of MMV007564 resistance, parasites were cultured in the presence of
the compound to generate resistant lines. Whole genome sequencing
revealed distinct mutations in the gene named Plasmodium
falciparum cyclic amine resistance locus (pfcarl), encoding a conserved protein of unknown function.
Mutations in pfcarl are strongly associated with
resistance to a structurally unrelated class of compounds, the imidazolopiperazines,
including KAF156, currently in clinical trials. Our data demonstrate
that pfcarl mutations confer resistance to two distinct
compound classes, benzimidazolyl piperidines and imidazolopiperazines.
However, MMV007564 and the imidazolopiperazines, KAF156 and GNF179,
have different timings of action in the asexual blood stage and different
potencies against the liver and sexual blood stages. These data suggest
that pfcarl is a multidrug-resistance gene rather
than a common target for benzimidazolyl piperidines and imidazolopiperazines.
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Affiliation(s)
- Pamela A. Magistrado
- Department
of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, United States
| | - Victoria C. Corey
- School
of Medicine, University of California—San Diego, La Jolla, California 92093, United States
| | - Amanda K. Lukens
- Department
of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, United States
- Infectious
Disease Program, The Broad Institute, 415 Main Street, Cambridge, Massachusetts 02142, United States
| | - Greg LaMonte
- School
of Medicine, University of California—San Diego, La Jolla, California 92093, United States
| | - Erika Sasaki
- School
of Medicine, University of California—San Diego, La Jolla, California 92093, United States
| | - Stephan Meister
- School
of Medicine, University of California—San Diego, La Jolla, California 92093, United States
| | - Melanie Wree
- School
of Medicine, University of California—San Diego, La Jolla, California 92093, United States
| | - Elizabeth Winzeler
- School
of Medicine, University of California—San Diego, La Jolla, California 92093, United States
| | - Dyann F. Wirth
- Department
of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, United States
- Infectious
Disease Program, The Broad Institute, 415 Main Street, Cambridge, Massachusetts 02142, United States
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48
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Metabolomics-Based Screening of the Malaria Box Reveals both Novel and Established Mechanisms of Action. Antimicrob Agents Chemother 2016; 60:6650-6663. [PMID: 27572396 DOI: 10.1128/aac.01226-16] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/16/2016] [Indexed: 12/22/2022] Open
Abstract
High-throughput phenotypic screening of chemical libraries has resulted in the identification of thousands of compounds with potent antimalarial activity, although in most cases, the mechanism(s) of action of these compounds remains unknown. Here we have investigated the mode of action of 90 antimalarial compounds derived from the Malaria Box collection using high-coverage, untargeted metabolomics analysis. Approximately half of the tested compounds induced significant metabolic perturbations in in vitro cultures of Plasmodium falciparum In most cases, the metabolic profiles were highly correlated with known antimalarials, in particular artemisinin, the 4-aminoquinolines, or atovaquone. Select Malaria Box compounds also induced changes in intermediates in essential metabolic pathways, such as isoprenoid biosynthesis (i.e., 2-C-methyl-d-erythritol 2,4-cyclodiphosphate) and linolenic acid metabolism (i.e., traumatic acid). This study provides a comprehensive database of the metabolic perturbations induced by chemically diverse inhibitors and highlights the utility of metabolomics for triaging new lead compounds and defining specific modes of action, which will assist with the development and optimization of new antimalarial drugs.
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49
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Metabolomic Profiling of the Malaria Box Reveals Antimalarial Target Pathways. Antimicrob Agents Chemother 2016; 60:6635-6649. [PMID: 27572391 DOI: 10.1128/aac.01224-16] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/16/2016] [Indexed: 12/11/2022] Open
Abstract
The threat of widespread drug resistance to frontline antimalarials has renewed the urgency for identifying inexpensive chemotherapeutic compounds that are effective against Plasmodium falciparum, the parasite species responsible for the greatest number of malaria-related deaths worldwide. To aid in the fight against malaria, a recent extensive screening campaign has generated thousands of lead compounds with low micromolar activity against blood stage parasites. A subset of these leads has been compiled by the Medicines for Malaria Venture (MMV) into a collection of structurally diverse compounds known as the MMV Malaria Box. Currently, little is known regarding the activity of these Malaria Box compounds on parasite metabolism during intraerythrocytic development, and a majority of the targets for these drugs have yet to be defined. Here we interrogated the in vitro metabolic effects of 189 drugs (including 169 of the drug-like compounds from the Malaria Box) using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). The resulting metabolic fingerprints provide information on the parasite biochemical pathways affected by pharmacologic intervention and offer a critical blueprint for selecting and advancing lead compounds as next-generation antimalarial drugs. Our results reveal several major classes of metabolic disruption, which allow us to predict the mode of action (MoA) for many of the Malaria Box compounds. We anticipate that future combination therapies will be greatly informed by these results, allowing for the selection of appropriate drug combinations that simultaneously target multiple metabolic pathways, with the aim of eliminating malaria and forestalling the expansion of drug-resistant parasites in the field.
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50
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Saggu GS, Pala ZR, Garg S, Saxena V. New Insight into Isoprenoids Biosynthesis Process and Future Prospects for Drug Designing in Plasmodium. Front Microbiol 2016; 7:1421. [PMID: 27679614 PMCID: PMC5020098 DOI: 10.3389/fmicb.2016.01421] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/26/2016] [Indexed: 12/20/2022] Open
Abstract
The MEP (Methyl Erythritol Phosphate) isoprenoids biosynthesis pathway is an attractive drug target to combat malaria, due to its uniqueness and indispensability for the parasite. It is functional in the apicoplast of Plasmodium and its products get transported to the cytoplasm, where they participate in glycoprotein synthesis, electron transport chain, tRNA modification and several other biological processes. Several compounds have been tested against the enzymes involved in this pathway and amongst them Fosmidomycin, targeted against IspC (DXP reductoisomerase) enzyme and MMV008138 targeted against IspD enzyme have shown good anti-malarial activity in parasite cultures. Fosmidomycin is now-a-days prescribed clinically, however, less absorption, shorter half-life, and toxicity at higher doses, limits its use as an anti-malarial. The potential of other enzymes of the pathway as candidate drug targets has also been determined. This review details the various drug molecules tested against these targets with special emphasis to Plasmodium. We corroborate that MEP pathway functional within the apicoplast of Plasmodium is a major drug target, especially during erythrocytic stages. However, the major bottlenecks, bioavailability and toxicity of the new molecules needs to be addressed, before considering any new molecule as a potent antimalarial.
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Affiliation(s)
- Gagandeep S Saggu
- Molecular Parasitology and Systems Biology Laboratory, Department of Biological Sciences, Birla Institute of Technology and Science Pilani, India
| | - Zarna R Pala
- Molecular Parasitology and Systems Biology Laboratory, Department of Biological Sciences, Birla Institute of Technology and Science Pilani, India
| | - Shilpi Garg
- Molecular Parasitology and Systems Biology Laboratory, Department of Biological Sciences, Birla Institute of Technology and Science Pilani, India
| | - Vishal Saxena
- Molecular Parasitology and Systems Biology Laboratory, Department of Biological Sciences, Birla Institute of Technology and Science Pilani, India
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