1
|
Chery-Karschney L, Patrapuvich R, Mudeppa DG, Kokkonda S, Chakrabarti R, Sriwichai P, O'Connor RM, Rathod PK, White J. Tartrolon E, a secondary metabolite of a marine symbiotic bacterium, is a potent inhibitor of asexual and sexual Plasmodium falciparum. Antimicrob Agents Chemother 2024; 68:e0068423. [PMID: 38193705 PMCID: PMC10848769 DOI: 10.1128/aac.00684-23] [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: 05/22/2023] [Accepted: 11/10/2023] [Indexed: 01/10/2024] Open
Abstract
Due to the spread of resistance to front-line artemisinin derivatives worldwide, there is a need for new antimalarials. Tartrolon E (TrtE), a secondary metabolite of a symbiotic bacterium of marine bivalve mollusks, is a promising antimalarial because it inhibits the growth of sexual and asexual blood stages of Plasmodium falciparum at sub-nanomolar levels. The potency of TrtE warrants further investigation into its mechanism of action, cytotoxicity, and ease with which parasites may evolve resistance to it.
Collapse
Affiliation(s)
| | - Rapatbhorn Patrapuvich
- Drug Research Unit for Malaria, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Sreekanth Kokkonda
- Department of Chemistry, University of Washington, Seattle, Washington, USA
| | - Rimi Chakrabarti
- Department of Chemistry, University of Washington, Seattle, Washington, USA
- Department of Medicine, Goa Medical College and Hospital, Bambolim, Goa, India
| | - Patchara Sriwichai
- Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Roberta M. O'Connor
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - John White
- Department of Chemistry, University of Washington, Seattle, Washington, USA
| |
Collapse
|
2
|
Miyazaki Y, Vos MW, Geurten FJA, Bigeard P, Kroeze H, Yoshioka S, Arisawa M, Inaoka DK, Soulard V, Dechering KJ, Franke-Fayard B, Miyazaki S. A versatile Plasmodium falciparum reporter line expressing NanoLuc enables highly sensitive multi-stage drug assays. Commun Biol 2023; 6:713. [PMID: 37438491 DOI: 10.1038/s42003-023-05078-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 06/27/2023] [Indexed: 07/14/2023] Open
Abstract
Transgenic luciferase-expressing Plasmodium falciparum parasites have been widely used for the evaluation of anti-malarial compounds. Here, to screen for anti-malarial drugs effective against multiple stages of the parasite, we generate a P. falciparum reporter parasite that constitutively expresses NanoLuciferase (NanoLuc) throughout its whole life cycle. The NanoLuc-expressing P. falciparum reporter parasite shows a quantitative NanoLuc signal in the asexual blood, gametocyte, mosquito, and liver stages. We also establish assay systems to evaluate the anti-malarial activity of compounds at the asexual blood, gametocyte, and liver stages, and then determine the 50% inhibitory concentration (IC50) value of several anti-malarial compounds. Through the development of this robust high-throughput screening system, we identify an anti-malarial compound that kills the asexual blood stage parasites. Our study highlights the utility of the NanoLuc reporter line, which may advance anti-malarial drug development through the improved screening of compounds targeting the human malarial parasite at multiple stages.
Collapse
Affiliation(s)
- Yukiko Miyazaki
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan.
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.
| | - Martijn W Vos
- TropIQ Health Sciences, Transistorweg 5, 6534 AT, Nijmegen, The Netherlands
| | - Fiona J A Geurten
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Pierre Bigeard
- Sorbonne Université, Inserm, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, F-75013, Paris, France
| | - Hans Kroeze
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Shohei Yoshioka
- Graduate School of Pharmaceutical Sciences, Osaka University, 565-0871, Osaka, Japan
| | - Mitsuhiro Arisawa
- Graduate School of Pharmaceutical Sciences, Osaka University, 565-0871, Osaka, Japan
| | - Daniel Ken Inaoka
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, 852-8523, Japan
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Valerie Soulard
- Sorbonne Université, Inserm, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, F-75013, Paris, France
| | - Koen J Dechering
- TropIQ Health Sciences, Transistorweg 5, 6534 AT, Nijmegen, The Netherlands
| | - Blandine Franke-Fayard
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Shinya Miyazaki
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
- Department of Cellular Architecture Studies, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan.
| |
Collapse
|
3
|
Muema JM, Mutunga JM, Obonyo MA, Getahun MN, Mwakubambanya RS, Akala HM, Cheruiyot AC, Yeda RA, Juma DW, Andagalu B, Johnson JL, Roth AL, Bargul JL. Isoliensinine from Cissampelos pariera rhizomes exhibits potential gametocytocidal and anti-malarial activities against Plasmodium falciparum clinical isolates. Malar J 2023; 22:161. [PMID: 37208735 DOI: 10.1186/s12936-023-04590-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 05/15/2023] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND The unmet demand for effective malaria transmission-blocking agents targeting the transmissible stages of Plasmodium necessitates intensive discovery efforts. In this study, a bioactive bisbenzylisoquinoline (BBIQ), isoliensinine, from Cissampelos pariera (Menispermaceae) rhizomes was identified and characterized for its anti-malarial activity. METHODS Malaria SYBR Green I fluorescence assay was performed to evaluate the in vitro antimalarial activity against D6, Dd2, and F32-ART5 clones, and immediate ex vivo (IEV) susceptibility for 10 freshly collected P. falciparum isolates. To determine the speed- and stage-of-action of isoliensinine, an IC50 speed assay and morphological analyses were performed using synchronized Dd2 asexuals. Gametocytocidal activity against two culture-adapted gametocyte-producing clinical isolates was determined using microscopy readouts, with possible molecular targets and their binding affinities deduced in silico. RESULTS Isoliensinine displayed a potent in vitro gametocytocidal activity at mean IC50gam values ranging between 0.41 and 0.69 µM for Plasmodium falciparum clinical isolates. The BBIQ compound also inhibited asexual replication at mean IC50Asexual of 2.17 µM, 2.22 µM, and 2.39 µM for D6, Dd2 and F32-ART5 respectively, targeting the late-trophozoite to schizont transition. Further characterization demonstrated a considerable immediate ex vivo potency against human clinical isolates at a geometric mean IC50IEV = 1.433 µM (95% CI 0.917-2.242). In silico analyses postulated a probable anti-malarial mechanism of action by high binding affinities for four mitotic division protein kinases; Pfnek1, Pfmap2, Pfclk1, and Pfclk4. Additionally, isoliensinine was predicted to possess an optimal pharmacokinetics profile and drug-likeness properties. CONCLUSION These findings highlight considerable grounds for further exploration of isoliensinine as an amenable scaffold for malaria transmission-blocking chemistry and target validation.
Collapse
Affiliation(s)
- Jackson M Muema
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya.
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya.
| | - James M Mutunga
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
- Department of Biological Sciences, School of Pure and Applied Sciences, Mount Kenya University, Thika, Kenya
- School of Engineering Design, Technology and Professional Programs, Pennsylvania State University, University Park, PA, 16802, USA
| | - Meshack A Obonyo
- Department of Biochemistry and Molecular Biology, Egerton University, Egerton, Kenya
| | - Merid N Getahun
- International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
| | | | - Hoseah M Akala
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Agnes C Cheruiyot
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Redemptah A Yeda
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Dennis W Juma
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Ben Andagalu
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Jaree L Johnson
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Amanda L Roth
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Joel L Bargul
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya.
- International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya.
| |
Collapse
|
4
|
Gametocyte-specific and all-blood-stage transmission-blocking chemotypes discovered from high throughput screening on Plasmodium falciparum gametocytes. Commun Biol 2022; 5:547. [PMID: 35668202 PMCID: PMC9170688 DOI: 10.1038/s42003-022-03510-w] [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: 02/09/2022] [Accepted: 05/19/2022] [Indexed: 11/25/2022] Open
Abstract
Blocking Plasmodium falciparum human-to-mosquito transmission is essential for malaria elimination, nonetheless drugs killing the pathogenic asexual stages are generally inactive on the parasite transmissible stages, the gametocytes. Due to technical and biological limitations in high throughput screening of non-proliferative stages, the search for gametocyte-killing molecules so far tested one tenth the number of compounds screened on asexual stages. Here we overcome these limitations and rapidly screened around 120,000 compounds, using not purified, bioluminescent mature gametocytes. Orthogonal gametocyte assays, selectivity assays on human cells and asexual parasites, followed by compound clustering, brought to the identification of 84 hits, half of which are gametocyte selective and half with comparable activity against sexual and asexual parasites. We validated seven chemotypes, three of which are, to the best of our knowledge, novel. These molecules are able to inhibit male gametocyte exflagellation and block parasite transmission through the Anopheles mosquito vector in a standard membrane feeding assay. This work shows that interrogating a wide and diverse chemical space, with a streamlined gametocyte HTS and hit validation funnel, holds promise for the identification of dual stage and gametocyte-selective compounds to be developed into new generation of transmission blocking drugs for malaria elimination. High-throughput screening of 120,000 compounds followed by counter-screening and validation assays reveals candidate antimalarial drugs that kill Plasmodium falciparum sexual and asexual blood stages blocking parasite transmission through mosquito.
Collapse
|
5
|
Consalvi S, Tammaro C, Appetecchia F, Biava M, Poce G. Malaria transmission blocking compounds: a patent review. Expert Opin Ther Pat 2022; 32:649-666. [PMID: 35240899 DOI: 10.1080/13543776.2022.2049239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Despite substantial progress in the field, malaria remains a global health issue and currently available control strategies are not sufficient to achieve eradication. Agents able to prevent transmission are likely to have a strong impact on malaria control and have been prioritized as a primary objective to reduce the number of secondary infections. Therefore, there is an increased interest in finding novel drugs targeting sexual stages of Plasmodium and innovative methods to target malaria transmission from host to vector, and vice versa. AREAS COVERED This review covers innovative transmission-blocking inventions patented between 2015 and October 2021. The focus is on chemical interventions which could be used as "chemical vaccines" to prevent transmission (small molecules, carbohydrates, and polypeptides). EXPERT OPINION Even though the development of novel strategies to block transmission still requires fundamental additional research and a deeper understanding of parasite sexual stages biology, the research in this field has significantly accelerated. Among innovative inventions patented over the last six years, the surface-delivery of antimalarial drugs to kill transmission-stages parasites in mosquitoes holds the highest promise for success in malaria control strategies, opening completely new scenarios in malaria transmission-blocking drug discovery.
Collapse
Affiliation(s)
- Sara Consalvi
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Chiara Tammaro
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Federico Appetecchia
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Mariangela Biava
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Giovanna Poce
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| |
Collapse
|
6
|
Birkholtz LM, Alano P, Leroy D. Transmission-blocking drugs for malaria elimination. Trends Parasitol 2022; 38:390-403. [DOI: 10.1016/j.pt.2022.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/19/2022] [Accepted: 01/24/2022] [Indexed: 12/24/2022]
|
7
|
Calleja-Felipe M, Wojtas MN, Diaz-González M, Ciceri D, Escribano R, Ouro A, Morales M, Knafo S. FORTIS: a live-cell assay to monitor AMPA receptors using pH-sensitive fluorescence tags. Transl Psychiatry 2021; 11:324. [PMID: 34045447 PMCID: PMC8160262 DOI: 10.1038/s41398-021-01457-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/09/2021] [Accepted: 05/18/2021] [Indexed: 11/26/2022] Open
Abstract
The real-time live fluorescent monitoring of surface AMPA receptors (AMPARs) could open new opportunities for drug discovery and phenotypic screening concerning neuropsychiatric disorders. We have developed FORTIS, a tool based on pH sensitivity capable of detecting subtle changes in surface AMPARs at a neuronal population level. The expression of SEP-GluA1 or pHuji-GluA1 recombinant AMPAR subunits in mammalian neurons cultured in 96-well plates enables surface AMPARs to be monitored with a microplate reader. Thus, FORTIS can register rapid changes in surface AMPARs induced by drugs or genetic modifications without having to rely on conventional electrophysiology or imaging. By combining FORTIS with pharmacological manipulations, basal surface AMPARs, and plasticity-like changes can be monitored. We expect that employing FORTIS to screen for changes in surface AMPARs will accelerate both neuroscience research and drug discovery.
Collapse
Affiliation(s)
- María Calleja-Felipe
- Department of Physiology and Cell Biology, Faculty of Health Sciences, The National Institute for Biotechnology in the Negev, and The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, E-48940, Spain
| | - Magdalena Natalia Wojtas
- Department of Physiology and Cell Biology, Faculty of Health Sciences, The National Institute for Biotechnology in the Negev, and The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Marta Diaz-González
- Department of Physiology and Cell Biology, Faculty of Health Sciences, The National Institute for Biotechnology in the Negev, and The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Dalila Ciceri
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, E-48940, Spain
| | - Raúl Escribano
- Fundación Biofísica Bizkaia/Biofisika Bizkaia Fundazioa (FBB), Barrio Sarriena s/n, Leioa, E-48940, Spain
| | - Alberto Ouro
- Department of Physiology and Cell Biology, Faculty of Health Sciences, The National Institute for Biotechnology in the Negev, and The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Miguel Morales
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, E-48940, Spain
| | - Shira Knafo
- Department of Physiology and Cell Biology, Faculty of Health Sciences, The National Institute for Biotechnology in the Negev, and The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, E-48940, Spain.
- Ikerbasque, Basque Foundation for Science, Bilbao, 48013, Spain.
| |
Collapse
|
8
|
Ferrarini MG, Nisimura LM, Girard RMBM, Alencar MB, Fragoso MSI, Araújo-Silva CA, Veiga ADA, Abud APR, Nardelli SC, Vommaro RC, Silber AM, France-Sagot M, Ávila AR. Dichloroacetate and Pyruvate Metabolism: Pyruvate Dehydrogenase Kinases as Targets Worth Investigating for Effective Therapy of Toxoplasmosis. mSphere 2021; 6:e01002-20. [PMID: 33408226 PMCID: PMC7845590 DOI: 10.1128/msphere.01002-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/09/2020] [Indexed: 12/31/2022] Open
Abstract
Toxoplasmosis, a protozoan infection caused by Toxoplasma gondii, is estimated to affect around 2.5 billion people worldwide. Nevertheless, the side effects of drugs combined with the long period of therapy usually result in discontinuation of the treatment. New therapies should be developed by exploring peculiarities of the parasite's metabolic pathways, similarly to what has been well described in cancer cell metabolism. An example is the switch in the metabolism of cancer that blocks the conversion of pyruvate into acetyl coenzyme A in mitochondria. In this context, dichloroacetate (DCA) is an anticancer drug that reverts the tumor proliferation by inhibiting the enzymes responsible for this switch: the pyruvate dehydrogenase kinases (PDKs). DCA has also been used in the treatment of certain symptoms of malaria; however, there is no evidence of how this drug affects apicomplexan species. In this paper, we studied the metabolism of T. gondii and demonstrate that DCA also inhibits T. gondii's in vitro infection with no toxic effects on host cells. DCA caused an increase in the activity of pyruvate dehydrogenase followed by an unbalanced mitochondrial activity. We also observed morphological alterations frequently in mitochondria and in a few apicoplasts, essential organelles for parasite survival. To date, the kinases that potentially regulate the activity of pyruvate metabolism in both organelles have never been described. Here, we confirmed the presence in the genome of two putative kinases (T. gondii PDK [TgPDK] and T. gondii branched-chain α-keto acid dehydrogenase kinase [TgBCKDK]), verified their cellular localization in the mitochondrion, and provided in silico data suggesting that they are potential targets of DCA.IMPORTANCE Currently, the drugs used for toxoplasmosis have severe toxicity to human cells, and the treatment still lacks effective and safer alternatives. The search for novel drug targets is timely. We report here that the treatment of T. gondii with an anticancer drug, dichloroacetate (DCA), was effective in decreasing in vitro infection without toxicity to human cells. It is known that PDK is the main target of DCA in mammals, and this inactivation increases the conversion of pyruvate into acetyl coenzyme A and reverts the proliferation of tumor cells. Moreover, we verified the mitochondrial localization of two kinases that possibly regulate the activity of pyruvate metabolism in T. gondii, which has never been studied. DCA increased pyruvate dehydrogenase (PDH) activity in T. gondii, followed by an unbalanced mitochondrial activity, in a manner similar to what was previously observed in cancer cells. Thus, we propose the conserved kinases as potential regulators of pyruvate metabolism and interesting targets for new therapies.
Collapse
Affiliation(s)
- Mariana Galvão Ferrarini
- Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, CNRS, Université de Lyon 1, Villeurbanne, France
| | - Lindice Mitie Nisimura
- Laboratório de Pesquisa em Apicomplexa, Instituto Carlos Chagas, Fiocruz, Paraná, Brazil
| | - Richard Marcel Bruno Moreira Girard
- Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Mayke Bezerra Alencar
- Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | | | - Carlla Assis Araújo-Silva
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alan de Almeida Veiga
- Laboratório de Pesquisa em Apicomplexa, Instituto Carlos Chagas, Fiocruz, Paraná, Brazil
| | | | | | - Rossiane C Vommaro
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ariel Mariano Silber
- Laboratory of Biochemistry of Tryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Marie France-Sagot
- Laboratoire de Biométrie et Biologie Évolutive, UMR 5558, CNRS, Université de Lyon 1, Villeurbanne, France
- INRIA Grenoble Rhône-Alpes, Montbonnot-Saint-Martin, France
| | - Andréa Rodrigues Ávila
- Laboratório de Pesquisa em Apicomplexa, Instituto Carlos Chagas, Fiocruz, Paraná, Brazil
| |
Collapse
|
9
|
Krishnan K, Ziniel P, Li H, Huang X, Hupalo D, Gombakomba N, Guerrero SM, Dotrang T, Lu X, Caridha D, Sternberg AR, Hughes E, Sun W, Bargieri DY, Roepe PD, Sciotti RJ, Wilkerson MD, Dalgard CL, Tawa GJ, Wang AQ, Xu X, Zheng W, Sanderson PE, Huang W, Williamson KC. Torin 2 Derivative, NCATS-SM3710, Has Potent Multistage Antimalarial Activity through Inhibition of P. falciparum Phosphatidylinositol 4-Kinase ( Pf PI4KIIIβ). ACS Pharmacol Transl Sci 2020; 3:948-964. [PMID: 33073193 DOI: 10.1021/acsptsci.0c00078] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Indexed: 12/25/2022]
Abstract
Drug resistance is a constant threat to malaria control efforts making it important to maintain a good pipeline of new drug candidates. Of particular need are compounds that also block transmission by targeting sexual stage parasites. Mature sexual stages are relatively resistant to all currently used antimalarials except the 8-aminoquinolines that are not commonly used due to potential side effects. Here, we synthesized a new Torin 2 derivative, NCATS-SM3710 with increased aqueous solubility and specificity for Plasmodium and demonstrate potent in vivo activity against all P. berghei life cycle stages. NCATS-SM3710 also has low nanomolar EC50s against in vitro cultured asexual P. falciparum parasites (0.38 ± 0.04 nM) and late stage gametocytes (5.77 ± 1 nM). Two independent NCATS-SM3710/Torin 2 resistant P. falciparum parasite lines produced by growth in sublethal Torin 2 concentrations both had genetic changes in PF3D7_0509800, annotated as a phosphatidylinositol 4 kinase (Pf PI4KIIIβ). One line had a point mutation in the putative active site (V1357G), and the other line had a duplication of a locus containing Pf PI4KIIIβ. Both lines were also resistant to other Pf PI4K inhibitors. In addition NCATS-SM3710 inhibited purified Pf PI4KIIIβ with an IC50 of 2.0 ± 0.30 nM. Together the results demonstrate that Pf PI4KIIIβ is the target of Torin 2 and NCATS-SM3710 and provide new options for potent multistage drug development.
Collapse
Affiliation(s)
- Karthik Krishnan
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Peter Ziniel
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Hao Li
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Xiuli Huang
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Daniel Hupalo
- Collaborative Health Initiative Research Program, Department of Anatomy, Physiology and Genetics Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Nita Gombakomba
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Sandra Mendoza Guerrero
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Thoai Dotrang
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Xiao Lu
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Diana Caridha
- Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
| | - Anna R Sternberg
- Departments of Chemistry and of Biochemistry, Cellular and Molecular Biology, Georgetown University, Washington, DC 20057, United States
| | - Emma Hughes
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Wei Sun
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Daniel Y Bargieri
- Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, 05508, Brazil
| | - Paul D Roepe
- Departments of Chemistry and of Biochemistry, Cellular and Molecular Biology, Georgetown University, Washington, DC 20057, United States
| | - Richard J Sciotti
- Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
| | - Matthew D Wilkerson
- Collaborative Health Initiative Research Program, Department of Anatomy, Physiology and Genetics Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Clifton L Dalgard
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States.,The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| | - Gregory J Tawa
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Amy Q Wang
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Xin Xu
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Wei Zheng
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Philip E Sanderson
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Wenwei Huang
- National Center for Advancing Translational Science, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Kim C Williamson
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, United States
| |
Collapse
|
10
|
Álvarez-Bardón M, Pérez-Pertejo Y, Ordóñez C, Sepúlveda-Crespo D, Carballeira NM, Tekwani BL, Murugesan S, Martinez-Valladares M, García-Estrada C, Reguera RM, Balaña-Fouce R. Screening Marine Natural Products for New Drug Leads against Trypanosomatids and Malaria. Mar Drugs 2020; 18:E187. [PMID: 32244488 PMCID: PMC7230869 DOI: 10.3390/md18040187] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 02/06/2023] Open
Abstract
Neglected Tropical Diseases (NTD) represent a serious threat to humans, especially for those living in poor or developing countries. Almost one-sixth of the world population is at risk of suffering from these diseases and many thousands die because of NTDs, to which we should add the sanitary, labor and social issues that hinder the economic development of these countries. Protozoan-borne diseases are responsible for more than one million deaths every year. Visceral leishmaniasis, Chagas disease or sleeping sickness are among the most lethal NTDs. Despite not being considered an NTD by the World Health Organization (WHO), malaria must be added to this sinister group. Malaria, caused by the apicomplexan parasite Plasmodium falciparum, is responsible for thousands of deaths each year. The treatment of this disease has been losing effectiveness year after year. Many of the medicines currently in use are obsolete due to their gradual loss of efficacy, their intrinsic toxicity and the emergence of drug resistance or a lack of adherence to treatment. Therefore, there is an urgent and global need for new drugs. Despite this, the scant interest shown by most of the stakeholders involved in the pharmaceutical industry makes our present therapeutic arsenal scarce, and until recently, the search for new drugs has not been seriously addressed. The sources of new drugs for these and other pathologies include natural products, synthetic molecules or repurposing drugs. The most frequent sources of natural products are microorganisms, e.g., bacteria, fungi, yeasts, algae and plants, which are able to synthesize many drugs that are currently in use (e.g. antimicrobials, antitumor, immunosuppressants, etc.). The marine environment is another well-established source of bioactive natural products, with recent applications against parasites, bacteria and other pathogens which affect humans and animals. Drug discovery techniques have rapidly advanced since the beginning of the millennium. The combination of novel techniques that include the genetic modification of pathogens, bioimaging and robotics has given rise to the standardization of High-Performance Screening platforms in the discovery of drugs. These advancements have accelerated the discovery of new chemical entities with antiparasitic effects. This review presents critical updates regarding the use of High-Throughput Screening (HTS) in the discovery of drugs for NTDs transmitted by protozoa, including malaria, and its application in the discovery of new drugs of marine origin.
Collapse
Affiliation(s)
- María Álvarez-Bardón
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Yolanda Pérez-Pertejo
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - César Ordóñez
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Daniel Sepúlveda-Crespo
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Nestor M. Carballeira
- Department of Chemistry, University of Puerto Rico, Río Piedras 00925-2537, San Juan, Puerto Rico;
| | - Babu L. Tekwani
- Department of Infectious Diseases, Division of Drug Discovery, Southern Research, Birmingham, AL 35205, USA;
| | - Sankaranarayanan Murugesan
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani Campus, Vidya Vihar, Pilani 333031, India;
| | - Maria Martinez-Valladares
- Department of Animal Health, Instituto de Ganadería de Montaña (CSIC-Universidad de León), Grulleros, 24346 León, Spain;
| | - Carlos García-Estrada
- INBIOTEC (Instituto de Biotecnología de León), Avda. Real 1-Parque Científico de León, 24006 León, Spain;
| | - Rosa M. Reguera
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Rafael Balaña-Fouce
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| |
Collapse
|
11
|
Plasmodium chaperonin TRiC/CCT identified as a target of the antihistamine clemastine using parallel chemoproteomic strategy. Proc Natl Acad Sci U S A 2020; 117:5810-5817. [PMID: 32127489 DOI: 10.1073/pnas.1913525117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The antihistamine clemastine inhibits multiple stages of the Plasmodium parasite that causes malaria, but the molecular targets responsible for its parasite inhibition were unknown. Here, we applied parallel chemoproteomic platforms to discover the mechanism of action of clemastine and identify that clemastine binds to the Plasmodium falciparum TCP-1 ring complex or chaperonin containing TCP-1 (TRiC/CCT), an essential heterooligomeric complex required for de novo cytoskeletal protein folding. Clemastine destabilized all eight P. falciparum TRiC subunits based on thermal proteome profiling (TPP). Further analysis using stability of proteins from rates of oxidation (SPROX) revealed a clemastine-induced thermodynamic stabilization of the Plasmodium TRiC delta subunit, suggesting an interaction with this protein subunit. We demonstrate that clemastine reduces levels of the major TRiC substrate tubulin in P. falciparum parasites. In addition, clemastine treatment leads to disorientation of Plasmodium mitotic spindles during the asexual reproduction and results in aberrant tubulin morphology suggesting protein aggregation. This clemastine-induced disruption of TRiC function is not observed in human host cells, demonstrating a species selectivity required for targeting an intracellular human pathogen. Our findings encourage larger efforts to apply chemoproteomic methods to assist in target identification of antimalarial drugs and highlight the potential to selectively target Plasmodium TRiC-mediated protein folding for malaria intervention.
Collapse
|
12
|
Tanaka TQ, Tokuoka SM, Nakatani D, Hamano F, Kawazu SI, Wellems TE, Kita K, Shimizu T, Tokumasu F. Polyunsaturated fatty acids promote Plasmodium falciparum gametocytogenesis. Biol Open 2019; 8:bio.042259. [PMID: 31221627 PMCID: PMC6679406 DOI: 10.1242/bio.042259] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The molecular triggers of sexual differentiation into gametocytes by blood stage Plasmodium falciparum, the most malignant human malaria parasites, are subject of much investigation for potential transmission-blocking strategies. The parasites are readily grown in vitro with culture media supplemented by the addition of human serum (10%) or by a commercially available substitute (0.5% AlbuMAX). We found better gametocytemia with serum than AlbuMAX, suggesting suboptimal concentrations of some components in the commercial product; consistent with this hypothesis, substantial concentration differences of multiple fatty acids were detected between serum- and AlbuMAX-supplemented media. Mass spectroscopy analysis distinguished the lipid profiles of gametocyte- and asexual stage-parasite membranes. Delivery of various combinations of unsaturated fatty-acid-containing phospholipids to AlbuMAX-supported gametocyte cultures improved gametocyte production to the levels achieved with human-serum-supplemented media. Maturing gametocytes readily incorporated externally supplied d5-labeled glycerol with fatty acids into unsaturated phospholipids. Phospholipids identified in this work thus may be taken up from extracellular sources or generated internally for important steps of gametocyte development. Further study of polyunsaturated fatty-acid metabolism and phospholipid profiles will improve understanding of gametocyte development and malaria parasite transmission.
Collapse
Affiliation(s)
- Takeshi Q Tanaka
- International Medical Zoology, Graduate School of Medicine, Kagawa University, Kagawa, 761-0793, Japan.,Laboratory of Malaria and Vector Research, National Institute of Allergy and Vector Research, National Institutes of Health, Bethesda, MD 20892-8132, USA.,Research Unit of Advanced Preventive Medicine, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Suzumi M Tokuoka
- Department of Lipidomics, Graduate School of Medicine, The University of Tokyo, Tokyo, 103-0033, Japan
| | - Daichi Nakatani
- Research Unit of Advanced Preventive Medicine, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Fumie Hamano
- Lipid Signaling Project, Research Institute National Center for Global Health and Medicine, Tokyo, 162-8655, Japan
| | - Shin-Ichiro Kawazu
- Research Unit of Advanced Preventive Medicine, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Vector Research, National Institutes of Health, Bethesda, MD 20892-8132, USA
| | - Kiyoshi Kita
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Takao Shimizu
- Department of Lipidomics, Graduate School of Medicine, The University of Tokyo, Tokyo, 103-0033, Japan.,Lipid Signaling Project, Research Institute National Center for Global Health and Medicine, Tokyo, 162-8655, Japan
| | - Fuyuki Tokumasu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Vector Research, National Institutes of Health, Bethesda, MD 20892-8132, USA .,Department of Lipidomics, Graduate School of Medicine, The University of Tokyo, Tokyo, 103-0033, Japan
| |
Collapse
|
13
|
Screening the Pathogen Box for Molecules Active against Plasmodium Sexual Stages Using a New Nanoluciferase-Based Transgenic Line of P. berghei Identifies Transmission-Blocking Compounds. Antimicrob Agents Chemother 2018; 62:AAC.01053-18. [PMID: 30181368 DOI: 10.1128/aac.01053-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/28/2018] [Indexed: 12/12/2022] Open
Abstract
Malaria remains an important parasitic disease with a large morbidity and mortality burden. Plasmodium transmission-blocking (TB) compounds are essential for achieving malaria elimination efforts. Recent efforts to develop high-throughput screening (HTS) methods to identify compounds that inhibit or kill gametocytes, the Plasmodium sexual stage infectious to mosquitoes, have yielded insight into new TB compounds. However, the activities of these compounds against gametes, formed in the first minutes of mosquito infection, are typically not assessed, unless screened in a standard membrane feeding assay, a labor-intensive assay. We demonstrate here the generation of a Plasmodium model for drug screens against gametes and fertilization. The new P. berghei line, named Ookluc, was genetically and pharmacologically validated and scalable for HTS. Screening the Pathogen Box from the Medicines for Malaria Venture using the new model identified promising TB compounds. The use of Ookluc in different libraries of compounds may aid in the identification of transmission-blocking drugs not assessed in screens against asexual stages or gametocytes.
Collapse
|
14
|
Forkuo AD, Ansah C, Mensah KB, Annan K, Gyan B, Theron A, Mancama D, Wright CW. In vitro anti-malarial interaction and gametocytocidal activity of cryptolepine. Malar J 2017; 16:496. [PMID: 29282057 PMCID: PMC5745596 DOI: 10.1186/s12936-017-2142-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 12/18/2017] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Discovery of novel gametocytocidal molecules is a major pharmacological strategy in the elimination and eradication of malaria. The high patronage of the aqueous root extract of the popular West African anti-malarial plant Cryptolepis sanguinolenta (Periplocaceae) in traditional and hospital settings in Ghana has directed this study investigating the gametocytocidal activity of the plant and its major alkaloid, cryptolepine. This study also investigates the anti-malarial interaction of cryptolepine with standard anti-malarials, as the search for new anti-malarial combinations continues. METHODS The resazurin-based assay was employed in evaluating the gametocytocidal properties of C. sanguinolenta and cryptolepine against the late stage (IV/V) gametocytes of Plasmodium falciparum (NF54). A fixed ratio method based on the SYBR Green I fluorescence-based assay was used to build isobolograms from a combination of cryptolepine with four standard anti-malarial drugs in vitro using the chloroquine sensitive strain 3D7. RESULTS Cryptolepis sanguinolenta (IC50 = 49.65 nM) and its major alkaloid, cryptolepine (IC50 = 1965 nM), showed high inhibitory activity against the late stage gametocytes of P. falciparum (NF54). In the interaction assays in asexual stage, cryptolepine showed an additive effect with both lumefantrine and chloroquine with mean ΣFIC50s of 1.017 ± 0.06 and 1.465 ± 0.17, respectively. Cryptolepine combination with amodiaquine at therapeutically relevant concentration ratios showed a synergistic effect (mean ΣFIC50 = 0.287 ± 0.10) whereas an antagonistic activity (mean ΣFIC50 = 4.182 ± 0.99) was seen with mefloquine. CONCLUSIONS The findings of this study shed light on the high gametocytocidal properties of C. sanguinolenta and cryptolepine attributing their potent anti-malarial activity mainly to their effect on both the sexual and asexual stages of the parasite. Amodiaquine is a potential drug partner for cryptolepine in the development of novel fixed dose combinations.
Collapse
Affiliation(s)
- Arnold Donkor Forkuo
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Charles Ansah
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Kwesi Boadu Mensah
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Kofi Annan
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ben Gyan
- Department of Immunology, Noguchi Memorial Institute for Biomedical Research, University of Ghana, Legon, Ghana
| | - Anjo Theron
- Biosciences, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria, 0001, South Africa
| | - Dalu Mancama
- Biosciences, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria, 0001, South Africa
| | - Colin W Wright
- School of Pharmacy, University of Bradford, West Yorkshire, BD7 1DP, UK
| |
Collapse
|
15
|
Sinha S, Sarma P, Sehgal R, Medhi B. Development in Assay Methods for in Vitro Antimalarial Drug Efficacy Testing: A Systematic Review. Front Pharmacol 2017; 8:754. [PMID: 29123481 PMCID: PMC5662882 DOI: 10.3389/fphar.2017.00754] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 10/04/2017] [Indexed: 11/13/2022] Open
Abstract
The emergence and spread of drug resistance are the major challenges in malaria eradication mission. Besides various strategies laid down by World Health Organization, such as vector management, source reduction, early case detection, prompt treatment, and development of new diagnostics and vaccines, nevertheless the need for new and efficacious drugs against malaria has become a critical priority on the global malaria research agenda. At several screening stages, millions of compounds are screened (1,000–2,000,000 compounds per screening campaign), before pre-clinical trials to select optimum lead. Carrying out in vitro screening of antimalarials is very difficult as different assay methods are subject to numerous sources of variability across different laboratories around the globe. Despite this, in vitro screening is an essential part of antimalarial drug development as it enables to resource various confounding factors such as host immune response and drug–drug interaction. Therefore, in this article, we try to illustrate the basic necessity behind in vitro study and how new methods are developed and subsequently adopted for high-throughput antimalarial drug screening and its application in achieving the next level of in vitro screening based on the current approaches (such as stem cells).
Collapse
Affiliation(s)
- Shweta Sinha
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Phulen Sarma
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rakesh Sehgal
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Bikash Medhi
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| |
Collapse
|
16
|
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.
Collapse
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.
| |
Collapse
|
17
|
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.
Collapse
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.
| |
Collapse
|
18
|
Affiliation(s)
- Robert E. Sinden
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail:
| |
Collapse
|
19
|
Hundreds of dual-stage antimalarial molecules discovered by a functional gametocyte screen. Nat Commun 2017; 8:15160. [PMID: 28513586 PMCID: PMC5442318 DOI: 10.1038/ncomms15160] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 03/03/2017] [Indexed: 02/07/2023] Open
Abstract
Plasmodium falciparum stage V gametocytes are responsible for parasite transmission, and drugs targeting this stage are needed to support malaria elimination. We here screen the Tres Cantos Antimalarial Set (TCAMS) using the previously developed P. falciparum female gametocyte activation assay (Pf FGAA), which assesses stage V female gametocyte viability and functionality using Pfs25 expression. We identify over 400 compounds with activities <2 μM, chemically classified into 57 clusters and 33 singletons. Up to 68% of the hits are chemotypes described for the first time as late-stage gametocyte-targeting molecules. In addition, the biological profile of 90 compounds representing the chemical diversity is assessed. We confirm in vitro transmission-blocking activity of four of the six selected molecules belonging to three distinct scaffold clusters. Overall, this TCAMS gametocyte screen provides 276 promising antimalarial molecules with dual asexual/sexual activity, representing starting points for target identification and candidate selection. There is a need for Plasmodium transmission blocking drugs for malaria elimination. Here, Miguel-Blanco et al. screen >10,000 compounds against stage V female gametocytes, identify active compounds belonging to 57 chemotypes and confirm transmission blocking activity of four selected compounds in vitro.
Collapse
|
20
|
Sun W, Huang X, Li H, Tawa G, Fisher E, Tanaka TQ, Shinn P, Huang W, Williamson KC, Zheng W. Novel lead structures with both Plasmodium falciparum gametocytocidal and asexual blood stage activity identified from high throughput compound screening. Malar J 2017; 16:147. [PMID: 28407766 PMCID: PMC5390467 DOI: 10.1186/s12936-017-1805-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 04/06/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Blocking malaria transmission is an important step in eradicating malaria. In the field, transmission requires the production of sexual stage Plasmodium parasites, called gametocytes, which are not effectively killed by the commonly used anti-malarials allowing individuals to remain infectious after clearance of asexual parasites. METHODS To identify new gametocytocidal compounds, a library of 45,056 compounds with diverse structures was screened using a high throughput gametocyte viability assay. The characteristics of active hits were further evaluated against asexual stage parasites in a growth inhibition assay. Their cytotoxicity were tested against mammalian cells in a cytotoxicity assay. The chemical scaffold similarity of active hits were studied using scaffold cluster analysis. RESULTS A set of 23 compounds were identified and further confirmed for their activity against gametocytes. All the 23 confirmed compounds possess dual-activities against both gametocytes responsible for human to mosquito transmission and asexual parasites that cause the clinical symptoms. Three of these compounds were fourfold more active against gametocytes than asexual parasites. Further cheminformatic analysis revealed three sets of novel scaffolds, including highly selective 4-1H-pyrazol-5-yl piperidine analogs. CONCLUSIONS This study revealed important new structural scaffolds that can be used as starting points for dual activity anti-malarial drug development.
Collapse
Affiliation(s)
- Wei Sun
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892 USA
| | - Xiuli Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892 USA
| | - Hao Li
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892 USA
| | - Gregory Tawa
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892 USA
| | - Ethan Fisher
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892 USA
| | - Takeshi Q. Tanaka
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Bethesda, MD USA
| | - Paul Shinn
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892 USA
| | - Wenwei Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892 USA
| | - Kim C. Williamson
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 USA
| | - Wei Zheng
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Bethesda, MD 20892 USA
| |
Collapse
|
21
|
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.
Collapse
|
22
|
Siciliano G, Santha Kumar TR, Bona R, Camarda G, Calabretta MM, Cevenini L, Davioud-Charvet E, Becker K, Cara A, Fidock DA, Alano P. A high susceptibility to redox imbalance of the transmissible stages of Plasmodium falciparum revealed with a luciferase-based mature gametocyte assay. Mol Microbiol 2017; 104:306-318. [PMID: 28118506 DOI: 10.1111/mmi.13626] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2017] [Indexed: 12/18/2022]
Abstract
The goal to prevent Plasmodium falciparum transmission from humans to mosquitoes requires the identification of targetable metabolic processes in the mature (stage V) gametocytes, the sexual stages circulating in the bloodstream. This task is complicated by the apparently low metabolism of these cells, which renders them refractory to most antimalarial inhibitors and constrains the development of specific and sensitive cell-based assays. Here, we identify and functionally characterize the regulatory regions of the P. falciparum gene PF3D7_1234700, encoding a CPW-WPC protein and named here Upregulated in Late Gametocytes (ULG8), which we have leveraged to express reporter genes in mature male and female gametocytes. Using transgenic parasites containing a pfULG8-luciferase cassette, we investigated the susceptibility of stage V gametocytes to compounds specifically affecting redox metabolism. Our results reveal a high sensitivity of mature gametocytes to the glutathione reductase inhibitor and redox cycler drug methylene blue (MB). Using isobologram analysis, we find that a concomitant inhibition of the parasite enzyme glucose-6-phosphate dehydrogenase-6-phosphogluconolactonase, a key component of NADPH synthesis, potently synergizes MB activity. These data suggest that redox metabolism and detoxification activity play an unsuspected yet vital role in stage V gametocytes, rendering these cells exquisitely sensitive to decreases in NADPH concentration.
Collapse
Affiliation(s)
- Giulia Siciliano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | - T R Santha Kumar
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA
| | - Roberta Bona
- Dipartimento Farmaco, Istituto Superiore di Sanità, Rome, Italy
| | - Grazia Camarda
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | | | - Luca Cevenini
- Department of Chemistry "G. Ciamician", University of Bologna, Bologna, Italy
| | - Elisabeth Davioud-Charvet
- European School of Chemistry, Polymers and Materials (ECPM), UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, Strasbourg, France
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Germany
| | - Andrea Cara
- Dipartimento Farmaco, Istituto Superiore di Sanità, Rome, Italy
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA.,Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY, USA
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| |
Collapse
|
23
|
Davies HM, Thalassinos K, Osborne AR. Expansion of Lysine-rich Repeats in Plasmodium Proteins Generates Novel Localization Sequences That Target the Periphery of the Host Erythrocyte. J Biol Chem 2016; 291:26188-26207. [PMID: 27777305 PMCID: PMC5207086 DOI: 10.1074/jbc.m116.761213] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Indexed: 01/05/2023] Open
Abstract
Repetitive low complexity sequences, mostly assumed to have no function, are common in proteins that are exported by the malaria parasite into its host erythrocyte. We identify a group of exported proteins containing short lysine-rich tandemly repeated sequences that are sufficient to localize to the erythrocyte periphery, where key virulence-related modifications to the plasma membrane and the underlying cytoskeleton are known to occur. Efficiency of targeting is dependent on repeat number, indicating that novel targeting modules could evolve by expansion of short lysine-rich sequences. Indeed, analysis of fragments of GARP from different species shows that two novel targeting sequences have arisen via the process of repeat expansion in this protein. In the protein Hyp12, the targeting function of a lysine-rich sequence is masked by a neighboring repetitive acidic sequence, further highlighting the importance of repetitive low complexity sequences. We show that sequences capable of targeting the erythrocyte periphery are present in at least nine proteins from Plasmodium falciparum and one from Plasmodium knowlesi. We find these sequences in proteins known to be involved in erythrocyte rigidification and cytoadhesion as well as in previously uncharacterized exported proteins. Together, these data suggest that expansion and contraction of lysine-rich repeats could generate targeting sequences de novo as well as modulate protein targeting efficiency and function in response to selective pressure.
Collapse
Affiliation(s)
- Heledd M Davies
- From the Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck and University College London, London WC1E 6BT, United Kingdom
| | - Konstantinos Thalassinos
- From the Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck and University College London, London WC1E 6BT, United Kingdom
| | - Andrew R Osborne
- From the Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck and University College London, London WC1E 6BT, United Kingdom
| |
Collapse
|
24
|
Bahamontes-Rosa N, Gomez-Lorenzo MG, Lelièvre J, Rodriguez Alejandre A, Almela MJ, Lozano S, Herreros E, Gamo FJ. A novel validated assay to support the discovery of new anti-malarial gametocytocidal agents. Malar J 2016; 15:385. [PMID: 27448565 PMCID: PMC4957904 DOI: 10.1186/s12936-016-1429-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/05/2016] [Indexed: 11/21/2022] Open
Abstract
Background Drugs that kill or inhibit Plasmodium gametocytes in the human host could potentially synergize the impact of other chemotherapeutic interventions by blocking transmission. To develop such agents, reliable methods are needed to study the in vitro activity of compounds against gametocytes. This study describes a novel assay for characterizing the activity of anti-malarial drugs against the later stages of Plasmodium falciparum gametocyte development using real-time PCR (qPCR). Methods Genes previously reported to be transcribed at the different sexual stages of the gametocytogenesis were selected for study and their mRNA expression was measured in a gametocytogenesis course by qPCR. Genes mainly expressed in the later stages of gametocyte development were used as a surrogate measurement of drug activity. To distinguish between cidal and static drug effects, two different experiments were performed in parallel, one with constant drug pressure throughout the experiment (144 h), and another in which the gametocyte cultures were exposed to the compound for only 48 h. Results Four P.falciparum genes coding for proteins Pf77, ROM3, Pfs25, and Pfg377 with transcription specific for late-stage gametocyte development were identified. The in vitro anti-malarial activity of compounds against such gametocytes was assessed by measuring mRNA levels of these genes using qPCR. The assay was validated against standard anti-malarial drugs (epoxomicin, dihydroartemisinin, chloroquine, thiostrepton, and methylene blue) and compounds from the GSK compound library with known anti-gametocyte activity. Conclusions This study describes a novel assay for characterizing the activity of anti-malarial drugs against the later stages of P. falciparum gametocyte development using qPCR in genetically unmodified parasites. The method described is a reliable and user-friendly technique with a medium throughput that could be easily implemented in any laboratory. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1429-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Noemí Bahamontes-Rosa
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain.
| | - María G Gomez-Lorenzo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Joël Lelièvre
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Ane Rodriguez Alejandre
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - María Jesus Almela
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Sonia Lozano
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Esperanza Herreros
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Francisco-Javier Gamo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| |
Collapse
|
25
|
Hovlid ML, Winzeler EA. Phenotypic Screens in Antimalarial Drug Discovery. Trends Parasitol 2016; 32:697-707. [PMID: 27247245 DOI: 10.1016/j.pt.2016.04.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 04/21/2016] [Indexed: 12/11/2022]
Abstract
Phenotypic high-throughput screens are a valuable tool for identifying new chemical compounds with antimalarial activity. Traditionally, these screens have focused solely on the symptomatic asexual blood stage of the parasite life cycle; however, to discover new medicines for malaria treatment and prevention, robust screening technologies against other parasite life-cycle stages are required. This review highlights recent advances and progress toward phenotypic screening methodologies over the past several years, with a focus on exoerythrocytic stage screens.
Collapse
Affiliation(s)
- Marisa L Hovlid
- School of Medicine, Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California, San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Elizabeth A Winzeler
- School of Medicine, Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California, San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA.
| |
Collapse
|
26
|
Birkholtz LM, Coetzer TL, Mancama D, Leroy D, Alano P. Discovering New Transmission-Blocking Antimalarial Compounds: Challenges and Opportunities. Trends Parasitol 2016; 32:669-681. [PMID: 27209388 DOI: 10.1016/j.pt.2016.04.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/24/2016] [Accepted: 04/26/2016] [Indexed: 01/08/2023]
Abstract
The ability to target human-mosquito parasite transmission challenges global malaria elimination. However, it is not obvious what a transmission-blocking drug will look like; should it target only parasite transmission stages; be combined with a partner drug killing the pathogenic asexual stages; or kill both the sexual and asexual blood stages, preferably displaying polypharmacology? The development of transmission-blocking antimalarials requires objective analyses of the current strategies. Here, pertinent issues and questions regarding the target candidate profile of a transmission-blocking compound, and its role in malaria elimination strategies, are highlighted and novel perspectives proposed. The essential role of a test cascade that integrates screening and validation strategies to identify next-generation transmission-blocking antimalarials is emphasised.
Collapse
Affiliation(s)
- Lyn-Marie Birkholtz
- Department of Biochemistry, Centre for Sustainable Malaria Control, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa.
| | - Theresa L Coetzer
- Department of Molecular Medicine and Haematology, Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, National Health Laboratory Service, Johannesburg, South Africa.
| | - Dalu Mancama
- Department of Biochemistry, Centre for Sustainable Malaria Control, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa; Biosciences, Council for Scientific and Industrial Research, Pretoria, South Africa.
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland.
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Rome, Italy.
| |
Collapse
|
27
|
Duffy S, Loganathan S, Holleran JP, Avery VM. Large-scale production of Plasmodium falciparum gametocytes for malaria drug discovery. Nat Protoc 2016; 11:976-92. [PMID: 27123949 DOI: 10.1038/nprot.2016.056] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The tightly controlled induction of Plasmodium falciparum gametocytes in large-scale culture is a fundamental requirement for malaria drug discovery applications including, but not limited to, high-throughput screening. This protocol uses magnetic separation for isolation of hemozoin-containing parasites in order to (i) increase parasitemia, (ii) decrease hematocrit and (iii) introduce higher levels of young red blood cells in a culture simultaneously within 2-4 h. These parameters, along with red blood cell lysis products that are generated through schizont rupture, are highly relevant for enabling optimum induction of gametocytogenesis in vitro. No other previously published protocols have applied this particular approach for parasite isolation and maximization of fresh red blood cells before inducing gametocytogenesis, which is essential for obtaining highly synchronous gametocyte classical stages on a large scale. In summary, 500-1,000 million stage IV gametocytes can be obtained within 16 d from an initial 10 ml of asexual blood-stage culture.
Collapse
Affiliation(s)
- Sandra Duffy
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Sasdekumar Loganathan
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - John P Holleran
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Vicky M Avery
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| |
Collapse
|
28
|
Patel PR, Sun W, Kim M, Huang X, Sanderson PE, Tanaka TQ, McKew JC, Simeonov A, Williamson KC, Zheng W, Huang W. In vitro evaluation of imidazo[4,5-c]quinolin-2-ones as gametocytocidal antimalarial agents. Bioorg Med Chem Lett 2016; 26:2907-2911. [PMID: 27156776 DOI: 10.1016/j.bmcl.2016.04.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 04/15/2016] [Accepted: 04/16/2016] [Indexed: 11/30/2022]
Abstract
Novel imidazo[4,5-c]quinolin-2-ones were synthesized and evaluated in asexual blood stage and late stage gametocyte assays of Plasmodium falciparum, a major causative agent of malaria. The design of these compounds is based on a recently identified lead compound from a high throughput screen. A concise synthesis was developed that allowed for generation of analogues with substitution around both the quinoline and imidazolidinone rings. Through structure-activity relationship studies, a number of potent compounds were identified that possessed excellent antimalarial activity against both the asexual and sexual stages with minimal cytotoxicity in mammalian cells. This is the first Letter describing SAR and gametocytocidal activity of imidazo[4,5-c]quinolin-2-ones, a new lead series for malaria treatment and prevention.
Collapse
Affiliation(s)
- Paresma R Patel
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States
| | - Wei Sun
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States
| | - Myunghoon Kim
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States
| | - Xiuli Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States
| | - Philip E Sanderson
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States
| | - Takeshi Q Tanaka
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, United States
| | - John C McKew
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States
| | - Kim C Williamson
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, United States
| | - Wei Zheng
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States
| | - Wenwei Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, United States.
| |
Collapse
|
29
|
Luciferase-Based, High-Throughput Assay for Screening and Profiling Transmission-Blocking Compounds against Plasmodium falciparum Gametocytes. Antimicrob Agents Chemother 2016; 60:2097-107. [PMID: 26787698 DOI: 10.1128/aac.01949-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 01/11/2016] [Indexed: 01/11/2023] Open
Abstract
The discovery of new antimalarial drugs able to target both the asexual and gametocyte stages ofPlasmodium falciparumis critical to the success of the malaria eradication campaign. We have developed and validated a robust, rapid, and cost-effective high-throughput reporter gene assay to identify compounds active against late-stage (stage IV and V) gametocytes. The assay, which is suitable for testing compound activity at incubation times up to 72 h, demonstrates excellent quality and reproducibility, with averageZ' values of 0.85 ± 0.01. We used the assay to screen more than 10,000 compounds from three chemically diverse libraries. The screening outcomes highlighted the opportunity to use collections of compounds with known activity against the asexual stages of the parasites as a starting point for gametocytocidal activity detection in order to maximize the chances of identifying gametocytocidal compounds. This assay extends the capabilities of our previously reported luciferase assay, which tested compounds against early-stage gametocytes, and opens possibilities to profile the activities of gametocytocidal compounds over the entire course of gametocytogenesis.
Collapse
|
30
|
Plouffe DM, Wree M, Du AY, Meister S, Li F, Patra K, Lubar A, Okitsu SL, Flannery EL, Kato N, Tanaseichuk O, Comer E, Zhou B, Kuhen K, Zhou Y, Leroy D, Schreiber SL, Scherer CA, Vinetz J, Winzeler EA. High-Throughput Assay and Discovery of Small Molecules that Interrupt Malaria Transmission. Cell Host Microbe 2015; 19:114-26. [PMID: 26749441 PMCID: PMC4723716 DOI: 10.1016/j.chom.2015.12.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/13/2015] [Accepted: 12/11/2015] [Indexed: 11/18/2022]
Abstract
Preventing transmission is an important element of malaria control. However, most of the current available methods to assay for malaria transmission blocking are relatively low throughput and cannot be applied to large chemical libraries. We have developed a high-throughput and cost-effective assay, the Saponin-lysis Sexual Stage Assay (SaLSSA), for identifying small molecules with transmission-blocking capacity. SaLSSA analysis of 13,983 unique compounds uncovered that >90% of well-characterized antimalarials, including endoperoxides and 4-aminoquinolines, as well as compounds active against asexual blood stages, lost most of their killing activity when parasites developed into metabolically quiescent stage V gametocytes. On the other hand, we identified compounds with consistent low nanomolar transmission-blocking activity, some of which showed cross-reactivity against asexual blood and liver stages. The data clearly emphasize substantial physiological differences between sexual and asexual parasites and provide a tool and starting points for the discovery and development of transmission-blocking drugs.
Collapse
Affiliation(s)
- David M Plouffe
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Melanie Wree
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Alan Y Du
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Stephan Meister
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Fengwu Li
- Division of Infectious Disease, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Kailash Patra
- Division of Infectious Disease, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Aristea Lubar
- Division of Infectious Disease, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Shinji L Okitsu
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Erika L Flannery
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Nobutaka Kato
- Broad Institute, 415 Main Street, Cambridge MA 02142
| | - Olga Tanaseichuk
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Eamon Comer
- Broad Institute, 415 Main Street, Cambridge MA 02142
| | - Bin Zhou
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Kelli Kuhen
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Yingyao Zhou
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Didier Leroy
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 Route de Pré-Bois, 1215 Geneva 15, Switzerland
| | - Stuart L Schreiber
- Broad Institute, 415 Main Street, Cambridge MA 02142; Department of Chemistry and Chemical Biology, Harvard University, 7 Cambridge Center, Cambridge, MA 02142, USA
| | | | - Joseph Vinetz
- Division of Infectious Disease, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Elizabeth A Winzeler
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| |
Collapse
|
31
|
In Vitro Activities of Primaquine-Schizonticide Combinations on Asexual Blood Stages and Gametocytes of Plasmodium falciparum. Antimicrob Agents Chemother 2015; 59:7650-6. [PMID: 26416869 DOI: 10.1128/aac.01948-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/23/2015] [Indexed: 12/28/2022] Open
Abstract
Currently, the World Health Organization recommends addition of a 0.25-mg base/kg single dose of primaquine (PQ) to artemisinin combination therapies (ACTs) for Plasmodium falciparum malaria as a gametocytocidal agent for reducing transmission. Here, we investigated the potential interactions of PQ with the long-lasting components of the ACT drugs for eliminating the asexual blood stages and gametocytes of in vitro-cultured P. falciparum strains. Using the SYBR green I assay for asexual parasites and a flow cytometry-based assay for gametocytes, we determined the interactions of PQ with the schizonticides chloroquine, mefloquine, piperaquine, lumefantrine, and naphthoquine. With the sums of fractional inhibitory concentrations and isobolograms, we were able to determine mostly synergistic interactions for the various PQ and schizonticide combinations on the blood stages of P. falciparum laboratory strains. The synergism in inhibiting asexual stages and gametocytes was highly evident with PQ-naphthoquine, whereas synergism was moderate for the PQ-piperaquine, PQ-chloroquine, and PQ-mefloquine combinations. We have detected potentially antagonistic interactions between PQ and lumefantrine under certain drug combination ratios, suggesting that precautions might be needed when PQ is added as the gametocytocide to the artemether-lumefantrine ACT (Coartem).
Collapse
|
32
|
An assay to probe Plasmodium falciparum growth, transmission stage formation and early gametocyte development. Nat Protoc 2015; 10:1131-42. [PMID: 26134953 DOI: 10.1038/nprot.2015.072] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Conversion from asexual proliferation to sexual differentiation initiates the production of the gametocyte, which is the malaria parasite stage required for human-to-mosquito transmission. This protocol describes an assay designed to probe the effect of drugs or other perturbations on asexual replication, sexual conversion and early gametocyte development in the major human malaria parasite Plasmodium falciparum. Synchronized asexually replicating parasites are induced for gametocyte production by the addition of conditioned medium, and they are then exposed to the treatment of interest during sexual commitment or at any subsequent stage of early gametocyte development. Flow cytometry is used to measure asexual proliferation and gametocyte production via DNA dye staining and the gametocyte-specific expression of a fluorescent protein, respectively. This screening approach may be used to identify and evaluate potential transmission-blocking compounds and to further investigate the mechanism of sexual conversion in malaria parasites. The full protocol can be completed in 11 d.
Collapse
|
33
|
Duez J, Holleran JP, Ndour PA, Pionneau C, Diakité S, Roussel C, Dussiot M, Amireault P, Avery VM, Buffet PA. Mechanical clearance of red blood cells by the human spleen: Potential therapeutic applications of a biomimetic RBC filtration method. Transfus Clin Biol 2015; 22:151-7. [PMID: 26138907 DOI: 10.1016/j.tracli.2015.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Indexed: 01/09/2023]
Abstract
During their lifespan, circulating RBC are frequently checked for their deformability. This mechanical quality control operates essentially in the human spleen. RBC unable to squeeze though narrow splenic slits are retained and cleared from the blood circulation. Under physiological conditions this prevents microvessels from being clogged by senescent, rigid RBC. Retention of poorly deformable RBC is an important determinant of pathogenesis in malaria and may also impact the clinical benefit of transfusion. Modulating the splenic retention of RBC has already been proposed to support therapeutic approaches in these research fields. To this aim, the development of microplates for high throughput filtration of RBC through microsphere layers (microplate-based microsphiltration) has been undertaken. This review focuses on potential therapeutic applications provided by this technology in malaria chemotherapy and transfusion.
Collapse
Affiliation(s)
- J Duez
- CIMI-Paris U1135, équipe 4, hôpital La Pitié-Salpêtrière, 75013 Paris, France; Laboratoire d'excellence GR-Ex, 24, boulevard du Montparnasse, 75015, Paris, France; HRA Pharma Laboratoires, 15, rue de Béranger, 75003 Paris, France; Eskitis Institute for Drug Discovery, Griffith University, Brisbane Innovation Park, Don Young Road, Nathan, QLD 4111, Australia
| | - J P Holleran
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane Innovation Park, Don Young Road, Nathan, QLD 4111, Australia
| | - P A Ndour
- CIMI-Paris U1135, équipe 4, hôpital La Pitié-Salpêtrière, 75013 Paris, France; Laboratoire d'excellence GR-Ex, 24, boulevard du Montparnasse, 75015, Paris, France
| | - C Pionneau
- CIMI-Paris Plateforme post-génomique de la Pitié Salpêtrière, P3S, hôpital La Pitié-Salpêtrière, 75013 Paris, France
| | - S Diakité
- CIMI-Paris U1135, équipe 4, hôpital La Pitié-Salpêtrière, 75013 Paris, France; Laboratoire d'excellence GR-Ex, 24, boulevard du Montparnasse, 75015, Paris, France
| | - C Roussel
- Laboratoire d'excellence GR-Ex, 24, boulevard du Montparnasse, 75015, Paris, France; Inserm U1163/CNRS ERL 8254, Imagine Institute, Paris Descartes-Sorbonne Paris Cité University, 75015 Paris, France; Institut national de la transfusion sanguine (INTS), 75015 Paris, France
| | - M Dussiot
- Laboratoire d'excellence GR-Ex, 24, boulevard du Montparnasse, 75015, Paris, France; Inserm U1163/CNRS ERL 8254, Imagine Institute, Paris Descartes-Sorbonne Paris Cité University, 75015 Paris, France; Institut national de la transfusion sanguine (INTS), 75015 Paris, France
| | - P Amireault
- Laboratoire d'excellence GR-Ex, 24, boulevard du Montparnasse, 75015, Paris, France; Inserm U1163/CNRS ERL 8254, Imagine Institute, Paris Descartes-Sorbonne Paris Cité University, 75015 Paris, France; Institut national de la transfusion sanguine (INTS), 75015 Paris, France
| | - V M Avery
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane Innovation Park, Don Young Road, Nathan, QLD 4111, Australia
| | - P A Buffet
- CIMI-Paris U1135, équipe 4, hôpital La Pitié-Salpêtrière, 75013 Paris, France; Laboratoire d'excellence GR-Ex, 24, boulevard du Montparnasse, 75015, Paris, France.
| |
Collapse
|
34
|
Reader J, Botha M, Theron A, Lauterbach SB, Rossouw C, Engelbrecht D, Wepener M, Smit A, Leroy D, Mancama D, Coetzer TL, Birkholtz LM. Nowhere to hide: interrogating different metabolic parameters of Plasmodium falciparum gametocytes in a transmission blocking drug discovery pipeline towards malaria elimination. Malar J 2015; 14:213. [PMID: 25994518 PMCID: PMC4449569 DOI: 10.1186/s12936-015-0718-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/22/2015] [Indexed: 12/23/2022] Open
Abstract
Background The discovery of malaria transmission-blocking compounds is seen as key to malaria elimination strategies and gametocyte-screening platforms are critical filters to identify active molecules. However, unlike asexual parasite assays measuring parasite proliferation, greater variability in end-point readout exists between different gametocytocidal assays. This is compounded by difficulties in routinely producing viable, functional and stage-specific gametocyte populations. Here, a parallel evaluation of four assay platforms on the same gametocyte populations was performed for the first time. This allowed the direct comparison of the ability of different assay platforms to detect compounds with gametocytocidal activity and revealed caveats in some assay readouts that interrogate different parasite biological functions. Methods Gametocytogenesis from Plasmodium falciparum (NF54) was optimized with a robust and standardized protocol. ATP, pLDH, luciferase reporter and PrestoBlue® assays were compared in context of a set of 10 reference compounds. The assays were performed in parallel on the same gametocyte preparation (except for luciferase reporter lines) using the same drug preparations (48 h). The remaining parameters for each assay were all comparable. Results A highly robust method for generating viable and functional gametocytes was developed and comprehensively validated resulting in an average gametocytaemia of 4 %. Subsequent parallel assays for gametocytocidal activity indicated that different assay platforms were not able to screen compounds with variant chemical scaffolds similarly. Luciferase reporter assays revealed that synchronized stage-specific gametocyte production is essential for drug discovery, as differential susceptibility in various gametocyte developmental populations is evident. Conclusions With this study, the key parameters for assays aiming at testing the gametocytocidal activity of potential transmission blocking molecules against Plasmodium gametocytes were accurately dissected. This first and uniquely comparative study emphasizes differential effects seen with the use of different assay platforms interrogating variant biological systems. Whilst this data is informative from a biological perspective and may provide indications of the drug mode of action, it does highlight the care that must be taken when screening broad-diversity chemotypes with a single assay platform against gametocytes for which the biology is not clearly understood. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0718-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Janette Reader
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Mariëtte Botha
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Anjo Theron
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, 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.
| | - Claire Rossouw
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, South Africa.
| | - Dewaldt Engelbrecht
- 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.
| | - Melanie Wepener
- 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.
| | - Annél Smit
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland.
| | - 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
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| |
Collapse
|
35
|
Splenic retention of Plasmodium falciparum gametocytes to block the transmission of malaria. Antimicrob Agents Chemother 2015; 59:4206-14. [PMID: 25941228 DOI: 10.1128/aac.05030-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/29/2015] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum is transmitted from humans to Anopheles mosquito vectors via the sexual erythrocytic forms termed gametocytes. Erythrocyte filtration through microsphere layers (microsphiltration) had shown that circulating gametocytes are deformable. Compounds reducing gametocyte deformability would induce their splenic clearance, thus removing them from the blood circulation and blocking malaria transmission. The hand-made, single-sample prototype for microsphiltration was miniaturized to a 96-well microtiter plate format, and gametocyte retention in the microsphere filters was quantified by high-content imaging. The stiffening activity of 40 pharmacological compounds was assessed in microtiter plates, using a small molecule (calyculin) as a positive control. The stiffening activity of calyculin was assessed in spleen-mimetic microfluidic chips and in macrophage-depleted mice. Marked mechanical retention (80% to 90%) of mature gametocytes was obtained in microplates following exposure to calyculin at concentrations with no effect on parasite viability. Of the 40 compounds tested, including 20 antimalarials, only 5 endoperoxides significantly increased gametocyte retention (1.5- to 2.5-fold; 24 h of exposure at 1 μM). Mature gametocytes exposed to calyculin accumulated in microfluidic chips and were cleared from the circulation of macrophage-depleted mice as rapidly as heat-stiffened erythrocytes, thus confirming results obtained using the microsphiltration assay. An automated miniaturized approach to select compounds for their gametocyte-stiffening effect has been established. Stiffening induces gametocyte clearance both in vitro and in vivo. Based on physiologically validated tools, this screening cascade can identify novel compounds and uncover new targets to block malaria transmission. Innovative applications in hematology are also envisioned.
Collapse
|
36
|
Dantzler KW, Ravel DB, Brancucci NM, Marti M. Ensuring transmission through dynamic host environments: host-pathogen interactions in Plasmodium sexual development. Curr Opin Microbiol 2015; 26:17-23. [PMID: 25867628 DOI: 10.1016/j.mib.2015.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 03/09/2015] [Indexed: 01/08/2023]
Abstract
A renewed global commitment to malaria elimination lends urgency to understanding the biology of Plasmodium transmission stages. Recent progress toward uncovering the mechanisms underlying Plasmodium falciparum sexual differentiation and maturation reveals potential targets for transmission-blocking drugs and vaccines. The identification of parasite factors that alter sexual differentiation, including extracellular vesicles and a master transcriptional regulator, suggest that parasites make epigenetically controlled developmental decisions based on environmental cues. New insights into sexual development, especially host cell remodeling and sequestration in the bone marrow, highlight open questions regarding parasite homing to the tissue, transmigration across the vascular endothelium, and maturation in the parenchyma. Novel molecular and translational tools will provide further opportunities to define host-parasite interactions and design effective transmission-blocking therapeutics.
Collapse
Affiliation(s)
- Kathleen W Dantzler
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Deepali B Ravel
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Nicolas Mb Brancucci
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
| |
Collapse
|
37
|
Imaging-based high-throughput screening assay to identify new molecules with transmission-blocking potential against Plasmodium falciparum female gamete formation. Antimicrob Agents Chemother 2015; 59:3298-305. [PMID: 25801574 DOI: 10.1128/aac.04684-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/16/2015] [Indexed: 11/20/2022] Open
Abstract
In response to a call for the global eradication of malaria, drug discovery has recently been extended to identify compounds that prevent the onward transmission of the parasite, which is mediated by Plasmodium falciparum stage V gametocytes. Lately, metabolic activity has been used in vitro as a surrogate for gametocyte viability; however, as gametocytes remain relatively quiescent at this stage, their ability to undergo onward development (gamete formation) may be a better measure of their functional viability. During gamete formation, female gametocytes undergo profound morphological changes and express translationally repressed mRNA. By assessing female gamete cell surface expression of one such repressed protein, Pfs25, as the readout for female gametocyte functional viability, we developed an imaging-based high-throughput screening (HTS) assay to identify transmission-blocking compounds. This assay, designated the P. falciparum female gametocyte activation assay (FGAA), was scaled up to a high-throughput format (Z' factor, 0.7 ± 0.1) and subsequently validated using a selection of 50 known antimalarials from diverse chemical families. Only a few of these agents showed submicromolar 50% inhibitory concentrations in the assay: thiostrepton, methylene blue, and some endoperoxides. To determine the best conditions for HTS, a robustness test was performed with a selection of the GlaxoSmithKline Tres Cantos Antimalarial Set (TCAMS) and the final screening conditions for this library were determined to be a 2 μM concentration and 48 h of incubation with gametocytes. The P. falciparum FGAA has been proven to be a robust HTS assay faithful to Plasmodium transmission-stage cell biology, and it is an innovative useful tool for antimalarial drug discovery which aims to identify new molecules with transmission-blocking potential.
Collapse
|
38
|
Class B, Thorne N, Aguisanda F, Southall N, McKew JC, Zheng W. High-throughput viability assay using an autonomously bioluminescent cell line with a bacterial Lux reporter. ACTA ACUST UNITED AC 2014; 20:164-74. [PMID: 25447977 DOI: 10.1177/2211068214560608] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cell viability assays are extensively used to determine cell health, evaluate growth conditions, and assess compound cytotoxicity. Most existing assays are endpoint assays, in which data are collected at one time point after termination of the experiment. The time point at which toxicity of a compound is evident, however, depends on the mechanism of that compound. An ideal cell viability assay allows the determination of compound toxicity kinetically without having to terminate the assay prematurely. We optimized and validated a reagent-addition-free cell viability assay using an autoluminescent HEK293 cell line that stably expresses bacterial luciferase and all substrates necessary for bioluminescence. This cell viability assay can be used for real-time, long-term measurement of compound cytotoxicity in live cells with a signal-to-basal ratio of 20- to 200-fold and Z-factors of ~0.6 after 24-, 48- 72-, or 96-h incubation with compound. We also found that the potencies of nine cytotoxic compounds correlated well with those measured by four other commonly used cell viability assays. The results demonstrated that this kinetic cell viability assay using the HEK293(lux) autoluminescent cell line is useful for high-throughput evaluation of compound cytotoxicity.
Collapse
Affiliation(s)
- Bradley Class
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Natasha Thorne
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Francis Aguisanda
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Noel Southall
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - John C McKew
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Wei Zheng
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
39
|
Sanders NG, Sullivan DJ, Mlambo G, Dimopoulos G, Tripathi AK. Gametocytocidal screen identifies novel chemical classes with Plasmodium falciparum transmission blocking activity. PLoS One 2014; 9:e105817. [PMID: 25157792 PMCID: PMC4144897 DOI: 10.1371/journal.pone.0105817] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 07/28/2014] [Indexed: 12/24/2022] Open
Abstract
Discovery of transmission blocking compounds is an important intervention strategy necessary to eliminate and eradicate malaria. To date only a small number of drugs that inhibit gametocyte development and thereby transmission from the mosquito to the human host exist. This limitation is largely due to a lack of screening assays easily adaptable to high throughput because of multiple incubation steps or the requirement for high gametocytemia. Here we report the discovery of new compounds with gametocytocidal activity using a simple and robust SYBR Green I- based DNA assay. Our assay utilizes the exflagellation step in male gametocytes and a background suppressor, which masks the staining of dead cells to achieve healthy signal to noise ratio by increasing signal of viable parasites and subtracting signal from dead parasites. By determining the contribution of exflagellation to fluorescent signal and using appropriate cutoff values, we were able to screen for gametocytocidal compounds. After assay validation and optimization, we screened an FDA approved drug library of approximately 1500 compounds, as well as the 400 compound MMV malaria box and identified 44 gametocytocidal compounds with sub to low micromolar IC50s. Major classes of compounds with gametocytocidal activity included quaternary ammonium compounds with structural similarity to choline, acridine-like compounds similar to quinacrine and pyronaridine, as well as antidepressant, antineoplastic, and anthelminthic compounds. Top drug candidates showed near complete transmission blocking in membrane feeding assays. This assay is simple, reproducible and demonstrated robust Z-factor values at low gametocytemia levels, making it amenable to HTS for identification of novel and potent gametocytocidal compounds.
Collapse
Affiliation(s)
- Natalie G. Sanders
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - David J. Sullivan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Godfree Mlambo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Abhai K. Tripathi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
| |
Collapse
|
40
|
Cevenini L, Camarda G, Michelini E, Siciliano G, Calabretta MM, Bona R, Kumar TRS, Cara A, Branchini BR, Fidock DA, Roda A, Alano P. Multicolor bioluminescence boosts malaria research: quantitative dual-color assay and single-cell imaging in Plasmodium falciparum parasites. Anal Chem 2014; 86:8814-21. [PMID: 25102353 PMCID: PMC4151787 DOI: 10.1021/ac502098w] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
New
reliable and cost-effective antimalarial drug screening assays
are urgently needed to identify drugs acting on different stages of
the parasite Plasmodium falciparum,
and particularly those responsible for human-to-mosquito transmission,
that is, the P. falciparum gametocytes.
Low Z′ factors, narrow dynamic ranges, and/or
extended assay times are commonly reported in current gametocyte assays
measuring gametocyte-expressed fluorescent or luciferase reporters,
endogenous ATP levels, activity of gametocyte enzymes, or redox-dependent
dye fluorescence. We hereby report on a dual-luciferase gametocyte
assay with immature and mature P. falciparum gametocyte stages expressing red and green-emitting luciferases
from Pyrophorus plagiophthalamus under
the control of the parasite sexual stage-specific pfs16 gene promoter. The assay was validated with reference antimalarial
drugs and allowed to quantitatively and simultaneously measure stage-specific
drug effects on parasites at different developmental stages. The optimized
assay, requiring only 48 h incubation with drugs and using a cost-effective
luminogenic substrate, significantly reduces assay cost and time in
comparison to state-of-the-art analogous assays. The assay had a Z′ factor of 0.71 ± 0.03, and it is suitable
for implementation in 96- and 384-well microplate formats. Moreover,
the use of a nonlysing d-luciferin substrate significantly
improved the reliability of the assay and allowed one to perform,
for the first time, P. falciparum bioluminescence
imaging at single-cell level.
Collapse
Affiliation(s)
- Luca Cevenini
- INBB, Istituto Nazionale di Biostrutture e Biosistemi , 00136 Rome, Italy
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Leroy D, Campo B, Ding XC, Burrows JN, Cherbuin S. Defining the biology component of the drug discovery strategy for malaria eradication. Trends Parasitol 2014; 30:478-90. [PMID: 25131411 DOI: 10.1016/j.pt.2014.07.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 10/24/2022]
Abstract
Malaria is still considered a deadly scourge in Africa, Asia, and South America despite improved vector control and curative treatments with new antimalarial combinations. The next challenge is to work towards disease eradication. To achieve this goal it is crucial to develop, validate, and integrate biological assays into test cascades that align with the key target product profiles. For anti-relapse, a parent molecule should kill hypnozoites or cause activation of Plasmodium vivax liver stages. For transmission blocking, dual equal-activity antimalarials killing both the asexual and the sexual parasite stages in human blood are favored. Finally, by assessing cross resistance and generating drug resistance in the laboratory, it is expected that new medicines with acceptable resistance profiles will be forthcoming.
Collapse
Affiliation(s)
- Didier Leroy
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 route de Pré-Bois, 1215 Geneva 15, Switzerland.
| | - Brice Campo
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 route de Pré-Bois, 1215 Geneva 15, Switzerland
| | - Xavier C Ding
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 route de Pré-Bois, 1215 Geneva 15, Switzerland
| | - Jeremy N Burrows
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 route de Pré-Bois, 1215 Geneva 15, Switzerland
| | - Stéphanie Cherbuin
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 route de Pré-Bois, 1215 Geneva 15, Switzerland
| |
Collapse
|
42
|
Chemical signatures and new drug targets for gametocytocidal drug development. Sci Rep 2014; 4:3743. [PMID: 24434750 PMCID: PMC3894558 DOI: 10.1038/srep03743] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/20/2013] [Indexed: 01/14/2023] Open
Abstract
Control of parasite transmission is critical for the eradication of malaria. However, most antimalarial drugs are not active against P. falciparum gametocytes, responsible for the spread of malaria. Consequently, patients can remain infectious for weeks after the clearance of asexual parasites and clinical symptoms. Here we report the identification of 27 potent gametocytocidal compounds (IC50 < 1 μM) from screening 5,215 known drugs and compounds. All these compounds were active against three strains of gametocytes with different drug sensitivities and geographical origins, 3D7, HB3 and Dd2. Cheminformatic analysis revealed chemical signatures for P. falciparum sexual and asexual stages indicative of druggability and suggesting potential targets. Torin 2, a top lead compound (IC50 = 8 nM against gametocytes in vitro), completely blocked oocyst formation in a mouse model of transmission. These results provide critical new leads and potential targets to expand the repertoire of malaria transmission-blocking reagents.
Collapse
|
43
|
Vial H, Taramelli D, Boulton IC, Ward SA, Doerig C, Chibale K. CRIMALDDI: platform technologies and novel anti-malarial drug targets. Malar J 2013; 12:396. [PMID: 24498961 PMCID: PMC3827883 DOI: 10.1186/1475-2875-12-396] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/22/2013] [Indexed: 12/24/2022] Open
Abstract
The Coordination, Rationalization, and Integration of antiMALarial drug Discovery & Development Initiatives (CRIMALDDI) Consortium, funded by the EU Framework Seven Programme, has attempted, through a series of interactive and facilitated workshops, to develop priorities for research to expedite the discovery of new anti-malarials. This paper outlines the recommendations for the development of enabling technologies and the identification of novel targets.Screening systems must be robust, validated, reproducible, and represent human malaria. They also need to be cost-effective. While such systems exist to screen for activity against blood stage Plasmodium falciparum, they are lacking for other Plasmodium spp. and other stages of the parasite's life cycle. Priority needs to be given to developing high-throughput screens that can identify activity against the liver and sexual stages. This in turn requires other enabling technologies to be developed to allow the study of these stages and to allow for the culture of liver cells and the parasite at all stages of its life cycle.As these enabling technologies become available, they will allow novel drug targets to be studied. Currently anti-malarials are mostly targeting the asexual blood stage of the parasite's life cycle. There are many other attractive targets that need to be investigated. The liver stages and the sexual stages will become more important as malaria control moves towards malaria elimination. Sexual development is a process offering multiple targets, even though the mechanisms of differentiation are still not fully understood. However, designing a drug whose effect is not curative but would be used in asymptomatic patients is difficult given current safety thresholds. Compounds active against the liver schizont would have a prophylactic effect and Plasmodium vivax elimination requires effectors against the dormant liver hypnozoites. It may be that drugs to be used in elimination campaigns will also need to have utility in the control phase. Compounds with activity against blood stages need to be screened for activity against other stages.Natural products should also be a valuable source of new compounds. They often occupy non-Lipinski chemical space and so may reveal valuable new chemotypes.
Collapse
Affiliation(s)
| | | | | | - Steve A Ward
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
| | | | | |
Collapse
|
44
|
Identification of MMV malaria box inhibitors of plasmodium falciparum early-stage gametocytes using a luciferase-based high-throughput assay. Antimicrob Agents Chemother 2013; 57:6050-62. [PMID: 24060871 DOI: 10.1128/aac.00870-13] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The design of new antimalarial combinations to treat Plasmodium falciparum infections requires drugs that, in addition to resolving disease symptoms caused by asexual blood stage parasites, can also interrupt transmission to the mosquito vector. Gametocytes, which are essential for transmission, develop as sexual blood stage parasites in the human host over 8 to 12 days and are the most accessible developmental stage for transmission-blocking drugs. Considerable effort is currently being devoted to identifying compounds active against mature gametocytes. However, investigations on the drug sensitivity of developing gametocytes, as well as screening methods for identifying inhibitors of early gametocytogenesis, remain scarce. We have developed a luciferase-based high-throughput screening (HTS) assay using tightly synchronous stage I to III gametocytes from a recombinant P. falciparum line expressing green fluorescent protein (GFP)-luciferase. The assay has been used to evaluate the early-stage gametocytocidal activity of the MMV Malaria Box, a collection of 400 compounds with known antimalarial (asexual blood stage) activity. Screening this collection against early-stage (I to III) gametocytes yielded 64 gametocytocidal compounds with 50% inhibitory concentrations (IC50s) below 2.5 μM. This assay is reproducible and suitable for the screening of large compound libraries, with an average percent coefficient of variance (%CV) of ≤5%, an average signal-to-noise ratio (S:N) of >30, and a Z' of ∼0.8. Our findings highlight the need for screening efforts directed specifically against early gametocytogenesis and indicate the importance of experimental verification of early-stage gametocytocidal activity in the development of new antimalarial candidates for combination therapy.
Collapse
|
45
|
Sykes ML, Avery VM. Approaches to Protozoan Drug Discovery: Phenotypic Screening. J Med Chem 2013; 56:7727-40. [DOI: 10.1021/jm4004279] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Melissa L. Sykes
- Discovery Biology, Eskitis Institute
for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Vicky M. Avery
- Discovery Biology, Eskitis Institute
for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| |
Collapse
|
46
|
Abstract
Drugs that kill or inhibit the sexual stages of Plasmodium in order to prevent transmission are important components of malaria control programmes. Reducing gametocyte carriage is central to the control of Plasmodium falciparum transmission as infection can result in extended periods of gametocytaemia. Unfortunately the number of drugs with activity against gametocytes is limited. Primaquine is currently the only licensed drug with activity against the sexual stages of malaria parasites and its use is hampered by safety concerns. This shortcoming is likely the result of the technical challenges associated with gametocyte studies together with the focus of previous drug discovery campaigns on asexual parasite stages. However recent emphasis on malaria eradication has resulted in an upsurge of interest in identifying compounds with activity against gametocytes. This review examines the gametocytocidal properties of currently available drugs as well as those in the development pipeline and examines the prospects for discovery of new anti-gametocyte compounds.
Collapse
|