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Verhoef JM, Boshoven C, Evers F, Akkerman LJ, Gijsbrechts BC, van de Vegte-Bolmer M, van Gemert GJ, Vaidya AB, Kooij TW. Detailing organelle division and segregation in Plasmodium falciparum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.30.577899. [PMID: 38352445 PMCID: PMC10862848 DOI: 10.1101/2024.01.30.577899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
The malaria causing parasite, Plasmodium falciparum, replicates through a tightly orchestrated process termed schizogony, where approximately 32 daughter parasites are formed in a single infected red blood cell and thousands of daughter cells in mosquito or liver stages. One-per-cell organelles, such as the mitochondrion and apicoplast, need to be properly divided and segregated to ensure a complete set of organelles per daughter parasites. Although this is highly essential, details about the processes and mechanisms involved remain unknown. We developed a new reporter parasite line that allows visualization of the mitochondrion in blood and mosquito stages. Using high-resolution 3D-imaging, we found that the mitochondrion orients in a cartwheel structure, prior to stepwise, non-geometric division during the last stage of schizogony. Analysis of focused ion beam scanning electron microscopy (FIB-SEM) data confirmed these mitochondrial division stages. Furthermore, these data allowed us to elucidate apicoplast division steps, highlighted its close association with the mitochondrion, and showed putative roles of the centriolar plaques (CPs) in apicoplast segregation. These observations form the foundation for a new detailed mechanistic model of mitochondrial and apicoplast division and segregation during P. falciparum schizogony and pave the way for future studies into the proteins and protein complexes involved in organelle division and segregation.
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Affiliation(s)
- Julie M.J. Verhoef
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cas Boshoven
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Felix Evers
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laura J. Akkerman
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Barend C.A. Gijsbrechts
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marga van de Vegte-Bolmer
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Akhil B. Vaidya
- Center for Molecular Parasitology, Institute for Molecular Medicine and Infectious Disease, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, USA
| | - Taco W.A. Kooij
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
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Abstract
As the world gets closer to eliminating malaria, the scientific community worldwide has begun to realize the importance of malaria transmission-blocking interventions. The onus of breaking the life cycle of the human malaria parasite Plasmodium falciparum predominantly rests upon transmission-blocking drugs because of emerging resistance to commonly used schizonticides and insecticides. This third part of our review series on malaria transmission-blocking entails transmission-blocking potential of preclinical transmission-blocking antimalarials and other non-malaria drugs/experimental compounds that are not in clinical or preclinical development for malaria but possess transmission-blocking potential. Collective analysis of the structure and the activity of these experimental compounds might pave the way toward generation of novel prototypes of next-generation transmission-blocking drugs.
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Abstract
The scientific community worldwide has realized that malaria elimination will not be possible without development of safe and effective transmission-blocking interventions. Primaquine, the only WHO recommended transmission-blocking drug, is not extensively utilized because of the toxicity issues in G6PD deficient individuals. Therefore, there is an urgent need to develop novel therapeutic interventions that can target malaria parasites and effectively block transmission. But at first, it is imperative to unravel the existing portfolio of transmission-blocking drugs. This review highlights transmission-blocking potential of current antimalarial drugs and drugs that are in various stages of clinical development. The collective analysis of the relationships between the structure and the activity of transmission-blocking drugs is expected to help in the design of new transmission-blocking antimalarials.
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Linzke M, Yan SLR, Tárnok A, Ulrich H, Groves MR, Wrenger C. Live and Let Dye: Visualizing the Cellular Compartments of the Malaria Parasite Plasmodium falciparum. Cytometry A 2019; 97:694-705. [PMID: 31738009 DOI: 10.1002/cyto.a.23927] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 10/03/2019] [Accepted: 10/24/2019] [Indexed: 12/15/2022]
Abstract
Malaria remains one of the deadliest diseases worldwide and it is caused by the protozoan parasite Plasmodium spp. Parasite visualization is an important tool for the correct detection of malarial cases but also to understand its biology. Advances in visualization techniques promote new insights into the complex life cycle and biology of Plasmodium parasites. Live cell imaging by fluorescence microscopy or flow cytometry are the foundation of the visualization technique for malaria research. In this review, we present an overview of possibilities in live cell imaging of the malaria parasite. We discuss some of the state-of-the-art techniques to visualize organelles and processes of the parasite and discuss limitation and advantages of each technique. © 2019 International Society for Advancement of Cytometry.
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Affiliation(s)
- Marleen Linzke
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
| | - Sun Liu Rei Yan
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
| | - Attila Tárnok
- Institute for Medical Informatics, Statistics and Epidemiology, Medical Faculty, University Leipzig, D-04107, Härtelstraße 16-18, Leipzig, Germany
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, São Paulo, São Paulo, 05508-900, Brazil
| | - Matthew R Groves
- Structural Biology Unit, Department of Pharmacy, Faculty of Science and Engineering, University of Groningen, 9713AV, Antonius Deusinglaan 1, AV Groningen, The Netherlands
| | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
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Ivermectin Impairs the Development of Sexual and Asexual Stages of Plasmodium falciparum In Vitro. Antimicrob Agents Chemother 2019; 63:AAC.00085-19. [PMID: 31109978 DOI: 10.1128/aac.00085-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022] Open
Abstract
Ivermectin is the drug of choice for many parasitic infections, with more than one billion doses being distributed in onchocerciasis programs. The drug has been put into focus recently by the malaria community because of its potential to kill blood-sucking mosquitoes, thereby reducing malaria transmission. However, the activity of ivermectin against the malaria parasite itself has been only partly investigated. This study aimed to investigate the in vitro activity of ivermectin against asexual and sexual stages of Plasmodium falciparum Both asexual and late-stage gametocytes were incubated with ivermectin and control drugs in vitro The growth-inhibiting effects were assessed for asexual stages of different Plasmodium falciparum laboratory strains and culture-adapted clinical isolates using the histidine-rich protein 2 enzyme-linked immunosorbent assay technique. The effect against stage IV/V gametocytes was evaluated based on ATP quantification. Ivermectin showed activities at nanomolar concentrations against asexual stages (50% inhibitory concentration of ∼100 nM) and stage IV/V gametocytes (500 nM) of P. falciparum Stage-specific assays suggested that ivermectin arrests the parasite cycle at the trophozoite stage. Ivermectin might add a feature to its "wonder drug" properties with activity against asexual stages of the malaria parasite Plasmodium falciparum The observed activities might be difficult to reach with current regimens but will be more relevant with future high-dose regimens under investigation. Further studies should be performed to confirm these results in vitro and in vivo.
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Mackwitz MKW, Hesping E, Antonova-Koch Y, Diedrich D, Woldearegai TG, Skinner-Adams T, Clarke M, Schöler A, Limbach L, Kurz T, Winzeler EA, Held J, Andrews KT, Hansen FK. Structure-Activity and Structure-Toxicity Relationships of Peptoid-Based Histone Deacetylase Inhibitors with Dual-Stage Antiplasmodial Activity. ChemMedChem 2019; 14:912-926. [PMID: 30664827 PMCID: PMC6502651 DOI: 10.1002/cmdc.201800808] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Indexed: 12/17/2022]
Abstract
Novel malaria intervention strategies are of great importance, given the development of drug resistance in malaria-endemic countries. In this regard, histone deacetylases (HDACs) have emerged as new and promising malaria drug targets. In this work, we present the design, synthesis, and biological evaluation of 20 novel HDAC inhibitors with antiplasmodial activity. Based on a previously discovered peptoid-based hit compound, we modified all regions of the peptoid scaffold by using a one-pot multicomponent pathway and submonomer routes to gain a deeper understanding of the structure-activity and structure-toxicity relationships. Most compounds displayed potent activity against asexual blood-stage P. falciparum parasites, with IC50 values in the range of 0.0052-0.25 μm and promising selectivity over mammalian cells (SIPf3D7/HepG2 : 170-1483). In addition, several compounds showed encouraging sub-micromolar activity against P. berghei exo-erythrocytic forms (PbEEF). Our study led to the discovery of the hit compound N-(2-(benzylamino)-2-oxoethyl)-N-(4-(hydroxycarbamoyl)benzyl)-4-isopropylbenzamide (2 h) as a potent and parasite-specific dual-stage antiplasmodial HDAC inhibitor (IC50 Pf3D7=0.0052 μm, IC50 PbEEF=0.016 μm).
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Affiliation(s)
- Marcel K W Mackwitz
- Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany
| | - Eva Hesping
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan, QLD, 4111, Australia
| | - Yevgeniya Antonova-Koch
- Department of Pediatrics, School of Medicine, University of California, San Diego, 9500 Gilman Drive 0741, La Jolla, CA, 92093, USA
| | - Daniela Diedrich
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Tamirat Gebru Woldearegai
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany
| | - Tina Skinner-Adams
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan, QLD, 4111, Australia
| | - Mary Clarke
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan, QLD, 4111, Australia
| | - Andrea Schöler
- Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany
| | - Laura Limbach
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Thomas Kurz
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Elizabeth A Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego, 9500 Gilman Drive 0741, La Jolla, CA, 92093, USA
| | - Jana Held
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany
| | - Katherine T Andrews
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan, QLD, 4111, Australia
| | - Finn K Hansen
- Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany
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Diedrich D, Stenzel K, Hesping E, Antonova-Koch Y, Gebru T, Duffy S, Fisher G, Schöler A, Meister S, Kurz T, Avery VM, Winzeler EA, Held J, Andrews KT, Hansen FK. One-pot, multi-component synthesis and structure-activity relationships of peptoid-based histone deacetylase (HDAC) inhibitors targeting malaria parasites. Eur J Med Chem 2018; 158:801-813. [PMID: 30245402 PMCID: PMC6195125 DOI: 10.1016/j.ejmech.2018.09.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 12/30/2022]
Abstract
Malaria drug discovery has shifted from a focus on targeting asexual blood stage parasites, to the development of drugs that can also target exo-erythrocytic forms and/or gametocytes in order to prevent malaria and/or parasite transmission. In this work, we aimed to develop parasite-selective histone deacetylase inhibitors (HDACi) with activity against the disease-causing asexual blood stages of Plasmodium malaria parasites as well as with causal prophylactic and/or transmission blocking properties. An optimized one-pot, multi-component protocol via a sequential Ugi four-component reaction and hydroxylaminolysis was used for the preparation of a panel of peptoid-based HDACi. Several compounds displayed potent activity against drug-sensitive and drug-resistant P. falciparum asexual blood stages, high parasite-selectivity and submicromolar activity against exo-erythrocytic forms of P. berghei. Our optimization study resulted in the discovery of the hit compound 1u which combines high activity against asexual blood stage parasites (Pf 3D7 IC50: 4 nM; Pf Dd2 IC50: 1 nM) and P. berghei exo-erythrocytic forms (Pb EEF IC50: 25 nM) with promising parasite-specific activity (SIPf3D7/HepG2: 2496, SIPfDd2/HepG2: 9990, and SIPbEEF/HepG2: 400).
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Affiliation(s)
- Daniela Diedrich
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Katharina Stenzel
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany; Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan Campus, QLD, 4111, Australia
| | - Eva Hesping
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan Campus, QLD, 4111, Australia
| | - Yevgeniya Antonova-Koch
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, 92093, United States
| | - Tamirat Gebru
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany
| | - Sandra Duffy
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan Campus, QLD, 4111, Australia
| | - Gillian Fisher
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan Campus, QLD, 4111, Australia
| | - Andrea Schöler
- Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany
| | - Stephan Meister
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, 92093, United States
| | - Thomas Kurz
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Vicky M Avery
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan Campus, QLD, 4111, Australia
| | - Elizabeth A Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, 92093, United States
| | - Jana Held
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany
| | - Katherine T Andrews
- Griffith Institute for Drug Discovery, Griffith University, Don Young Road, Nathan Campus, QLD, 4111, Australia.
| | - Finn K Hansen
- Institut für Pharmazeutische und Medizinische Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany; Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Medical Faculty, Leipzig University, Brüderstraße 34, 04103, Leipzig, Germany.
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8
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Wadi I, Pillai CR, Anvikar AR, Sinha A, Nath M, Valecha N. Methylene blue induced morphological deformations in Plasmodium falciparum gametocytes: implications for transmission-blocking. Malar J 2018; 17:11. [PMID: 29310655 PMCID: PMC5759873 DOI: 10.1186/s12936-017-2153-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 12/23/2017] [Indexed: 12/24/2022] Open
Abstract
Background Malaria remains a global health problem despite availability of effective tools. For malaria elimination, drugs targeting sexual stages of Plasmodium falciparum need to be incorporated in treatment regimen along with schizonticidal drugs to interrupt transmission. Primaquine is recommended as a transmission blocking drug for its effect on mature gametocytes but is not extensively utilized because of associated safety concerns among glucose-6-phosphate dehydrogenase (G6PD) deficient patients. In present work, methylene blue, which is proposed as an alternative to primaquine is investigated for its gametocytocidal activity amongst Indian field isolates. An effort has been made to establish Indian field isolates of P. falciparum as in vitro model for gametocytocidal drugs screening. Methods Plasmodium falciparum isolates were adapted to in vitro culture and induced to gametocyte production by hypoxanthine and culture was enriched for gametocyte stages using N-acetyl-glucosamine. Gametocytes were incubated with methylene blue for 48 h and stage specific gametocytocidal activity was evaluated by microscopic examination. Results Plasmodium falciparum field isolates RKL-9 and JDP-8 were able to reproducibly produce gametocytes in high yield and were used to screen gametocytocidal drugs. Methylene blue was found to target gametocytes in a concentration dependent manner by either completely eliminating gametocytes or rendering them morphologically deformed with mean IC50 (early stages) as 424.1 nM and mean IC50 (late stages) as 106.4 nM. These morphologically altered gametocytes appeared highly degenerated having shrinkage, distortions and membrane deformations. Conclusions Field isolates that produce gametocytes in high yield in vitro can be identified and used to screen gametocytocidal drugs. These isolates should be used for validation of gametocytocidal hits obtained previously by using lab adapted reference strains. Methylene blue was found to target gametocytes produced from Indian field isolates and is proposed to be used as a gametocytocidal adjunct with artemisinin-based combination therapy. Further exploration of methylene blue in clinical studies amongst Indian population, including G6PD deficient patients, is recommended.
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Affiliation(s)
- Ishan Wadi
- Indian Council of Medical Research-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110077, India. .,Department of Chemistry, University of Delhi, Delhi, 110007, India.
| | - C Radhakrishna Pillai
- Indian Council of Medical Research-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110077, India
| | - Anupkumar R Anvikar
- Indian Council of Medical Research-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110077, India
| | - Abhinav Sinha
- Indian Council of Medical Research-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110077, India
| | - Mahendra Nath
- Department of Chemistry, University of Delhi, Delhi, 110007, India
| | - Neena Valecha
- Indian Council of Medical Research-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110077, India
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Anastasova EI, Ivanovski V, Fakhardo AF, Lepeshkin AI, Omar S, Drozdov AS, Vinogradov VV. A pure magnetite hydrogel: synthesis, properties and possible applications. SOFT MATTER 2017; 13:8651-8660. [PMID: 29115351 DOI: 10.1039/c7sm01702b] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A magnetite-only hydrogel was prepared for the first time by weak base mediated gelation of stable magnetite hydrosols at room temperature. The hydrogel consists of 10 nm magnetite nanoparticles linked by interparticle Fe-O-Fe bonds and has the appearance of a dark-brown viscous thixotropic material. The water content in the hydrogel could be up to 93.6% by mass while volume fraction reaches 99%. The material shows excellent biocompatibility and minor cytotoxic effects at concentrations up to 207 μg mL-1. The gel shows excellent sorption capacity for heavy metal adsorption such as chrome and lead ions, which is 225% more than the adsorption capacity of magnetite nanoparticles. Due to thixotropic nature, the gel demonstrates mechanical stimuli-responsive release behavior with up to 98% release triggered by ultrasound irradiation. The material shows superparamagnetic behavior with a coercivity of 65 emu g-1 at 6000 Oe. The magnetite gels prepared could be used for the production of magnetite aerogels, magnetic drug delivery systems with controlled release and highly efficient sorbents for hydrometallurgy.
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Affiliation(s)
- Elizaveta I Anastasova
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, Saint-Petersburg, 197101, Russian Federation.
| | - Vladimir Ivanovski
- Faculty of Natural Sciences and Mathematics, Institute of Chemistry, Ss. Cyril and Methodius University in Skopje, Skopje, 1000, Republic of Macedonia
| | - Anna F Fakhardo
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, Saint-Petersburg, 197101, Russian Federation.
| | - Artem I Lepeshkin
- Chair of Applied Biotechnology, ITMO University, Saint-Petersburg, 197101, Russian Federation
| | - Suheir Omar
- Institute of Chemistry, Casali Center for Applied Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Andrey S Drozdov
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, Saint-Petersburg, 197101, Russian Federation.
| | - Vladimir V Vinogradov
- Laboratory of Solution Chemistry of Advanced Materials and Technologies, ITMO University, Saint-Petersburg, 197101, Russian Federation.
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Leba LJ, Popovici J, Estevez Y, Pelleau S, Legrand E, Musset L, Duplais C. Antiplasmodial activities of dyes against Plasmodium falciparum asexual and sexual stages: Contrasted uptakes of triarylmethanes Brilliant green, Green S (E142), and Patent Blue V (E131) by erythrocytes. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2017; 7:314-320. [PMID: 28886443 PMCID: PMC5587875 DOI: 10.1016/j.ijpddr.2017.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 07/27/2017] [Accepted: 07/31/2017] [Indexed: 11/07/2022]
Abstract
The search for safe antimalarial compounds acting against asexual symptom-responsible stages and sexual transmission-responsible forms of Plasmodium species is one of the major challenges in malaria elimination programs. So far, among current drugs approved for human use, only primaquine has transmission-blocking activity. The discovery of small molecules targeting different Plasmodium falciparum life stages remains a priority in antimalarial drug research. In this context, several independent studies have recently reported antiplasmodial and transmission-blocking activities of commonly used stains, dyes and fluorescent probes against P. falciparum including chloroquine-resistant isolates. Herein we have studied the antimalarial activities of dyes with different scaffold and we report that the triarylmethane dye (TRAM) Brilliant green inhibits the growth of asexual stages (IC50 ≤ 2 μM) and has exflagellation-blocking activity (IC50 ≤ 800 nM) against P. falciparum reference strains (3D7, 7G8) and chloroquine-resistant clinical isolate (Q206). In a second step we have investigated the antiplasmodial activities of two polysulfonated triarylmethane food dyes. Green S (E142) is weakly active against P. falciparum asexual stage (IC50 ≃ 17 μM) whereas Patent Blue V (E131) is inactive in both antimalarial assays. By applying liquid chromatography techniques for the culture supernatant analysis after cell washings and lysis, we report the detection of Brilliant green in erythrocytes, the selective uptake of Green S (E142) by infected erythrocytes, whereas Patent Blue V (E131) could not be detected within non-infected and 3D7-infected erythrocytes. Overall, our results suggest that two polysulfonated food dyes might display different affinity with transporters or channels on infected RBC membrane. Dyes are tested against P. falciparum 3D7, 7G8 lines, CQ-resistant field isolate Q206. Brilliant green is active against asexual and sexual stages of Plasmodium falciparum. Food dye Green S (E142) is weakly active against Plasmodium falciparum asexual forms. Food dye Green S (E142) is found in the cellular content of infected erythrocytes. Polysulfonated triarylmethane possibly interact with plasmodial surface anion channel.
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Affiliation(s)
- Louis-Jérôme Leba
- Laboratoire de parasitologie, CNR du paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana, France; UMR QualiSud, Université de Guyane, 97300 Cayenne, France
| | - Jean Popovici
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Yannick Estevez
- CNRS, UMR8172 EcoFoG, AgroParisTech, Cirad, INRA, Université des Antilles, Université de Guyane, 97300 Cayenne, French Guiana, France
| | - Stéphane Pelleau
- Laboratoire de parasitologie, CNR du paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana, France
| | - Eric Legrand
- Laboratoire de parasitologie, CNR du paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana, France; Research Unit of Genetics and Genomics of Insect Vectors Institut Pasteur, Paris, France
| | - Lise Musset
- Laboratoire de parasitologie, CNR du paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana, France
| | - Christophe Duplais
- CNRS, UMR8172 EcoFoG, AgroParisTech, Cirad, INRA, Université des Antilles, Université de Guyane, 97300 Cayenne, French Guiana, France.
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Gebru T, Lalremruata A, Kremsner PG, Mordmüller B, Held J. Life-span of in vitro differentiated Plasmodium falciparum gametocytes. Malar J 2017; 16:330. [PMID: 28800735 PMCID: PMC5553604 DOI: 10.1186/s12936-017-1986-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/07/2017] [Indexed: 11/18/2022] Open
Abstract
Background The sexual stages (gametocytes) of Plasmodium falciparum do not directly contribute to the pathology of malaria but are essential for transmission of the parasite from the human host to the mosquito. Mature gametocytes circulate in infected human blood for several days and their circulation time has been modelled mathematically from data of previous in vivo studies. This is the first time that longevity of gametocytes is studied experimentally in vitro. Methods The in vitro longevity of P. falciparum gametocytes of 1 clinical isolate and 2 laboratory strains was assessed by three different methods: microscopy, flow cytometry and reverse transcription quantitative real-time PCR (RT-qPCR). Additionally, the rate of gametocytogenesis of the used P. falciparum strains was compared. Results The maximum in vitro lifespan of P. falciparum gametocytes reached almost 2 months (49 days by flow cytometry, 46 days by microscopy, and at least 52 days by RT-qPCR) from the starting day of gametocyte culture to death of last parasite in the tested strains with an average 50% survival rate of 6.5, 2.6 and 3.5 days, respectively. Peak gametocytaemia was observed on average 19 days after initiation of gametocyte culture followed by a steady decline due to natural decay of the parasites. The rate of gametocytogenesis was highest in the NF54 strain. Conclusions Plasmodium falciparum mature gametocytes can survive up to 16–32 days (at least 14 days for mature male gametocytes) in vitro in absence of the influence of host factors. This confirms experimentally a previous modelling estimate that used molecular tools for gametocyte detection in treated patients. The survival time might reflect the time the parasite can be transmitted to the mosquito after clearance of asexual parasites. These results underline the importance of efficient transmission blocking agents in the fight against malaria. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1986-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tamirat Gebru
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany.,Department of Medical Laboratory Sciences, College of Medical and Health Sciences, Haramaya University, Harar, Ethiopia
| | - Albert Lalremruata
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany. .,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany.
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12
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Gebru T, Ajua A, Theisen M, Esen M, Ngoa UA, Issifou S, Adegnika AA, Kremsner PG, Mordmüller B, Held J. Recognition of Plasmodium falciparum mature gametocyte-infected erythrocytes by antibodies of semi-immune adults and malaria-exposed children from Gabon. Malar J 2017; 16:176. [PMID: 28446190 PMCID: PMC5406886 DOI: 10.1186/s12936-017-1827-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/19/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Transmission of malaria from man to mosquito depends on the presence of gametocytes, the sexual stage of Plasmodium parasites in the infected host. Naturally acquired antibodies against gametocytes exist and may play a role in controlling transmission by limiting the gametocyte development in the circulation or by interrupting gamete development and fertilization in the mosquito following ingestion. So far, most studies on antibody responses to sexual stage antigens have focused on a subset of gametocyte-surface antigens, even though inhibitory Ab responses to other gametocyte antigens might also play a role in controlling gametocyte density and fertility. Limited information is available on natural antibody response to the surfaces of gametocyte-infected erythrocytes. METHODS Ab responses to surface antigens of erythrocytes infected by in vitro differentiated Plasmodium falciparum mature gametocytes were investigated in sera of semi-immune adults and malaria-exposed children. In addition, the effect of immunization with GMZ2, a blood stage malaria vaccine candidate, and the effect of intestinal helminth infection on the development of immunity to gametocytes of P. falciparum was evaluated in malaria-exposed children and adults from Gabon. Serum samples from two Phase I clinical trials conducted in Gabon were analysed by microscopic and flow-cytometric immunofluorescence assay. RESULTS Adults had a higher Ab response compared to children. Ab reactivity was significantly higher after fixation and permeabilization of parasitized erythrocytes. Following vaccination with the malaria vaccine candidate GMZ2, anti-gametocyte Ab concentration decreased in adults compared to baseline. Ab response to whole asexual stage antigens had a significant but weak positive correlation to anti-gametocyte Ab responses in adults, but not in children. Children infected with Ascaris lumbricoides had a significantly higher anti-gametocyte Ab response compared to non-infected children. CONCLUSION The current data suggest that antigens exposed on the gametocyte-infected red blood cells are recognized by serum antibodies from malaria-exposed children and semi-immune adults. This anti-gametocyte immune response may be influenced by natural exposure and vaccination. Modulation of the natural immune response to gametocytes by co-infecting parasites should be investigated further and may have an important impact on malaria control strategies.
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Affiliation(s)
- Tamirat Gebru
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon.,Department of Medical Laboratory Sciences, College of Medical and Health Sciences, Haramaya University, Harar, Ethiopia
| | - Anthony Ajua
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Center for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Meral Esen
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon
| | - Ulysse Ateba Ngoa
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon.,Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Saadou Issifou
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Fondation pour la Recherche Scientifique (FORS), Cotonou, Benin
| | - Ayola A Adegnika
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon.,Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany. .,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany. .,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon. .,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon.
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13
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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.
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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
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14
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Lucantoni L, Silvestrini F, Signore M, Siciliano G, Eldering M, Dechering KJ, Avery VM, Alano P. A simple and predictive phenotypic High Content Imaging assay for Plasmodium falciparum mature gametocytes to identify malaria transmission blocking compounds. Sci Rep 2015; 5:16414. [PMID: 26553647 PMCID: PMC4639769 DOI: 10.1038/srep16414] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 10/14/2015] [Indexed: 11/15/2022] Open
Abstract
Plasmodium falciparum gametocytes, specifically the mature stages, are the only malaria parasite stage in humans transmissible to the mosquito vector. Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria and tools allowing the screening of large compound libraries with high predictive power are needed to identify new candidates. As gametocytes are not a replicative stage it is difficult to apply the same drug screening methods used for asexual stages. Here we propose an assay, based on high content imaging, combining “classic” gametocyte viability readout based on gametocyte counts with a functional viability readout, based on gametocyte activation and the discrimination of the typical gamete spherical morphology. This simple and rapid assay has been miniaturized to a 384-well format using acridine orange staining of wild type P. falciparum 3D7A sexual forms, and was validated by screening reference antimalarial drugs and the MMV Malaria Box. The assay demonstrated excellent robustness and ability to identify quality hits with high likelihood of confirmation of transmission reducing activity in subsequent mosquito membrane feeding assays.
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Affiliation(s)
- Leonardo Lucantoni
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, 4111 Nathan, Queensland, Australia
| | - Francesco Silvestrini
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n. 299, 00161 Roma, Italy
| | - Michele Signore
- Dipartimento di Ematologia, Oncologia e Medicina Molecolare, Istituto Superiore di Sanità, Viale Regina Elena n. 299, 00161 Roma, Italy
| | - Giulia Siciliano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n. 299, 00161 Roma, Italy
| | - Maarten Eldering
- TropIQ Health Sciences, Geert Grooteplein 28, huispost 268, 6525 GA Nijmegen, The Netherlands
| | - Koen J Dechering
- TropIQ Health Sciences, Geert Grooteplein 28, huispost 268, 6525 GA Nijmegen, The Netherlands
| | - Vicky M Avery
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, 4111 Nathan, Queensland, Australia
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n. 299, 00161 Roma, Italy
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15
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Leba LJ, Musset L, Pelleau S, Estevez Y, Birer C, Briolant S, Witkowski B, Ménard D, Delves MJ, Legrand E, Duplais C, Popovici J. Use of Plasmodium falciparum culture-adapted field isolates for in vitro exflagellation-blocking assay. Malar J 2015; 14:234. [PMID: 26040313 PMCID: PMC4464717 DOI: 10.1186/s12936-015-0752-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/27/2015] [Indexed: 12/01/2022] Open
Abstract
Background A major requirement for malaria elimination is the development of transmission-blocking interventions. In vitro transmission-blocking bioassays currently mostly rely on the use of very few Plasmodium falciparum reference laboratory strains isolated decades ago. To fill a piece of the gap between laboratory experimental models and natural systems, the purpose of this work was to determine if culture-adapted field isolates of P. falciparum are suitable for in vitro transmission-blocking bioassays targeting functional maturity of male gametocytes: exflagellation. Methods Plasmodium falciparum isolates were adapted to in vitro culture before being used for in vitro gametocyte production. Maturation was assessed by microscopic observation of gametocyte morphology over time of culture and the functional viability of male gametocytes was assessed by microscopic counting of exflagellating gametocytes. Suitability for in vitro exflagellation-blocking bioassays was determined using dihydroartemisinin and methylene blue. Results In vitro gametocyte production was achieved using two isolates from French Guiana and two isolates from Cambodia. Functional maturity of male gametocytes was assessed by exflagellation observations and all four isolates could be used in exflagellation-blocking bioassays with adequate response to methylene blue and dihydroartemisinin. Conclusion This work shows that in vitro culture-adapted P. falciparum field isolates of different genetic background, from South America and Southeast Asia, can successfully be used for bioassays targeting the male gametocyte to gamete transition, exflagellation. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0752-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Louis-Jérôme Leba
- Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. .,Laboratoire ECOFOG (Ecology of Guiana Forests) UMR8172 CNRS-INRA-CIRAD-AgroParisTech-Université des Antilles-Université de la Guyane, French Guiana, France.
| | - Lise Musset
- Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France.
| | - Stéphane Pelleau
- Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France.
| | - Yannick Estevez
- Laboratoire ECOFOG (Ecology of Guiana Forests) UMR8172 CNRS-INRA-CIRAD-AgroParisTech-Université des Antilles-Université de la Guyane, French Guiana, France.
| | - Caroline Birer
- Laboratoire ECOFOG (Ecology of Guiana Forests) UMR8172 CNRS-INRA-CIRAD-AgroParisTech-Université des Antilles-Université de la Guyane, French Guiana, France.
| | - Sébastien Briolant
- Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. .,Direction Interarmées du Service de Santé en Guyane, Cayenne, French Guiana, France. .,Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
| | - Didier Ménard
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
| | | | - Eric Legrand
- Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France.
| | - Christophe Duplais
- Laboratoire ECOFOG (Ecology of Guiana Forests) UMR8172 CNRS-INRA-CIRAD-AgroParisTech-Université des Antilles-Université de la Guyane, French Guiana, France.
| | - Jean Popovici
- Laboratoire de Parasitologie, Institut Pasteur de la Guyane, Cayenne, French Guiana, France. .,Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
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