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Kulkeaw K. Progress and challenges in the use of fluorescence-based flow cytometric assays for anti-malarial drug susceptibility tests. Malar J 2021; 20:57. [PMID: 33478496 PMCID: PMC7818911 DOI: 10.1186/s12936-021-03591-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/13/2021] [Indexed: 01/27/2023] Open
Abstract
Drug-resistant Plasmodium is a frequent global threat in malaria eradication programmes, highlighting the need for new anti-malarial drugs and efficient detection of treatment failure. Plasmodium falciparum culture is essential in drug discovery and resistance surveillance. Microscopy of Giemsa-stained erythrocytes is common for determining anti-malarial effects on the intraerythrocytic development of cultured Plasmodium parasites. Giemsa-based microscopy use is conventional but laborious, and its accuracy depends largely on examiner skill. Given the availability of nucleic acid-binding fluorescent dyes and advances in flow cytometry, the use of various fluorochromes has been frequently attempted for the enumeration of parasitaemia and discrimination of P. falciparum growth in drug susceptibility assays. However, fluorochromes do not meet the requirements of being fast, simple, reliable and sensitive. Thus, this review revisits the utility of fluorochromes, notes previously reported hindrances, and highlights the challenges and opportunities for using fluorochromes in flow cytometer-based drug susceptibility tests. It aims to improve drug discovery and support a resistance surveillance system, an essential feature in combatting malaria.
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Affiliation(s)
- Kasem Kulkeaw
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2, Wanglang Road, Bangkoknoi, 10700, Bangkok, Thailand.
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2
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Brown AC, Guler JL. From Circulation to Cultivation: Plasmodium In Vivo versus In Vitro. Trends Parasitol 2020; 36:914-926. [DOI: 10.1016/j.pt.2020.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 12/17/2022]
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Computational Chemogenomics Drug Repositioning Strategy Enables the Discovery of Epirubicin as a New Repurposed Hit for Plasmodium falciparum and P. vivax. Antimicrob Agents Chemother 2020; 64:AAC.02041-19. [PMID: 32601162 PMCID: PMC7449180 DOI: 10.1128/aac.02041-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 06/19/2020] [Indexed: 12/13/2022] Open
Abstract
Widespread resistance against antimalarial drugs thwarts current efforts for controlling the disease and urges the discovery of new effective treatments. Drug repositioning is increasingly becoming an attractive strategy since it can reduce costs, risks, and time-to-market. Herein, we have used this strategy to identify novel antimalarial hits. We used a comparative in silico chemogenomics approach to select Plasmodium falciparum and Plasmodium vivax proteins as potential drug targets and analyzed them using a computer-assisted drug repositioning pipeline to identify approved drugs with potential antimalarial activity. Widespread resistance against antimalarial drugs thwarts current efforts for controlling the disease and urges the discovery of new effective treatments. Drug repositioning is increasingly becoming an attractive strategy since it can reduce costs, risks, and time-to-market. Herein, we have used this strategy to identify novel antimalarial hits. We used a comparative in silico chemogenomics approach to select Plasmodium falciparum and Plasmodium vivax proteins as potential drug targets and analyzed them using a computer-assisted drug repositioning pipeline to identify approved drugs with potential antimalarial activity. Among the seven drugs identified as promising antimalarial candidates, the anthracycline epirubicin was selected for further experimental validation. Epirubicin was shown to be potent in vitro against sensitive and multidrug-resistant P. falciparum strains and P. vivax field isolates in the nanomolar range, as well as being effective against an in vivo murine model of Plasmodium yoelii. Transmission-blocking activity was observed for epirubicin in vitro and in vivo. Finally, using yeast-based haploinsufficiency chemical genomic profiling, we aimed to get insights into the mechanism of action of epirubicin. Beyond the target predicted in silico (a DNA gyrase in the apicoplast), functional assays suggested a GlcNac-1-P-transferase (GPT) enzyme as a potential target. Docking calculations predicted the binding mode of epirubicin with DNA gyrase and GPT proteins. Epirubicin is originally an antitumoral agent and presents associated toxicity. However, its antiplasmodial activity against not only P. falciparum but also P. vivax in different stages of the parasite life cycle supports the use of this drug as a scaffold for hit-to-lead optimization in malaria drug discovery.
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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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Bastos MF, Albrecht L, Gomes AM, Lopes SC, Vicente CP, de Almeida RP, Cassiano GC, Fonseca RJ, Werneck CC, Pavão MS, Costa FT. A new heparan sulfate from the mollusk Nodipecten nodosus inhibits merozoite invasion and disrupts rosetting and cytoadherence of Plasmodium falciparum. Mem Inst Oswaldo Cruz 2019; 114:e190088. [PMID: 31188952 PMCID: PMC6555591 DOI: 10.1590/0074-02760190088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/28/2019] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Despite treatment with effective antimalarial drugs, the mortality rate is
still high in severe cases of the disease, highlighting the need to find
adjunct therapies that can inhibit the adhesion of Plasmodium
falciparum-infected erythrocytes (Pf-iEs). OBJECTIVES In this context, we evaluated a new heparan sulfate (HS) from
Nodipecten nodosus for antimalarial activity and
inhibition of P. falciparum cytoadhesion and rosetting. METHODS Parasite inhibition was measured by SYBR green using a cytometer. HS was
assessed in rosetting and cytoadhesion assays under static and flow
conditions using Chinese hamster ovary (CHO) and human lymphatic endothelial
cell (HLEC) cells expressing intercellular adhesion molecule-1 (ICAM1) and
chondroitin sulfate A (CSA), respectively. FINDINGS This HS inhibited merozoite invasion similar to heparin. Moreover, mollusk
HS decreased cytoadherence of P. falciparum to CSA and
ICAM-1 on the surface of endothelial cells under static and flow conditions.
In addition, this glycan efficiently disrupted rosettes. CONCLUSIONS These findings support a potential use for mollusk HS as adjunct therapy for
severe malaria.
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Affiliation(s)
- Marcele F Bastos
- Universidade Estadual de Campinas, Departamento de Genética, Evolução, Microbiologia e Imunologia, Laboratório de Doenças Tropicais, Campinas, SP, Brasil
| | - Letusa Albrecht
- Fundação Oswaldo Cruz-Fiocruz, Instituto Carlos Chagas, Curitiba, PR, Brasil
| | - Angélica M Gomes
- Cleveland Clinic Lerner Research Institute, Department of Biomedical Engineering, Cleveland, OH, USA
| | - Stefanie Cp Lopes
- Fundação Oswaldo Cruz-Fiocruz, Instituto Leônidas e Maria Deane, Manaus, AM, Brasil
| | - Cristina P Vicente
- Universidade Estadual de Campinas, Departamento de Biologia Estrutural e Funcional, Campinas, SP, Brasil
| | | | - Gustavo C Cassiano
- Universidade Estadual de Campinas, Departamento de Genética, Evolução, Microbiologia e Imunologia, Laboratório de Doenças Tropicais, Campinas, SP, Brasil
| | - Roberto Jc Fonseca
- Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Instituto de Ciências Biomédicas, Hospital Universitário Clementino Fraga Filho, Laboratório de Tecido Conjuntivo, Rio de Janeiro, RJ, Brasil
| | - Claudio C Werneck
- Universidade Estadual de Campinas, Departamento de Bioquímica e Biologia Tecidual, Campinas, SP, Brasil
| | - Mauro Sg Pavão
- Universidade Federal do Rio de Janeiro, Instituto de Bioquímica Médica Leopoldo de Meis, Programa de Glicobiologia, Rio de Janeiro, RJ, Brasil
| | - Fabio Tm Costa
- Universidade Estadual de Campinas, Departamento de Genética, Evolução, Microbiologia e Imunologia, Laboratório de Doenças Tropicais, Campinas, SP, Brasil
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Cytotoxic CD8 + T cells recognize and kill Plasmodium vivax-infected reticulocytes. Nat Med 2018; 24:1330-1336. [PMID: 30038217 PMCID: PMC6129205 DOI: 10.1038/s41591-018-0117-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 06/05/2018] [Indexed: 01/02/2023]
Abstract
Plasmodium vivax causes approximately 100 million
clinical malaria cases yearly1,2. The basis of protective
immunity is poorly understood and thought to be mediated by antibodies3,4. Cytotoxic CD8+ T cells (CTLs)
protect against other intracellular parasites by detecting parasite peptides
presented by Human Leukocyte Antigen Class I (HLA-I) on host cells. CTLs kill
parasite-infected mammalian cells and intracellular parasites by releasing their
cytotoxic granules5,6. Perforin (PFN) delivers the
antimicrobial peptide granulysin (GNLY) and death-inducing granzymes (Gzm) into
the host cell, and GNLY then delivers Gzms into the parasite. CTLs were thought
to have no role against Plasmodium spp. blood stages because
red blood cells (RBCs) generally do not express HLA-I7. However, P. vivax
infects reticulocytes (Retics) that retain the protein translation machinery.
Here we show that P. vivax-infected Retics (iRetic) express
HLA-I. Infected patient circulating CD8+ T cells highly
express cytotoxic proteins and recognize and form immunological synapses with
iRetics in an HLA-dependent manner, releasing their cytotoxic granules to kill
both host cell and intracellular parasite, preventing reinvasion. iRetic and
parasite killing is PFN-independent, but depends on GNLY, which generally
efficiently forms pores only in microbial membranes8. We find that P. vivax
depletes cholesterol from the iRetic cell membrane, rendering it
GNLY-susceptible. This unexpected T cell defense might be mobilized to improve
P. vivax vaccine efficacy.
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Characterizing Blood-Stage Antimalarial Drug MIC Values In Vivo Using Reinfection Patterns. Antimicrob Agents Chemother 2018; 62:AAC.02476-17. [PMID: 29661873 PMCID: PMC6021672 DOI: 10.1128/aac.02476-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/27/2018] [Indexed: 12/01/2022] Open
Abstract
The MIC is an essential quantitative measure of the asexual blood-stage effect of an antimalarial drug. In areas of high malaria transmission, and thus frequent individual infection, patients who are treated with slowly eliminated antimalarials become reinfected as drug concentrations decline. In the frequent relapse forms of Plasmodium vivax and in Plasmodium ovale malaria, recurrent infection occurs from relapses which begin to emerge from the liver approximately 2 weeks after the primary illness. An important determinant of the interval from starting treatment of a symptomatic infection to the patency of these recurrent infections is the in vivo concentration-response relationship and thus the in vivo MIC. Using mechanistic knowledge of parasite asexual replication and the pharmacokinetic and pharmacodynamic properties of the antimalarial drugs, a generative statistical model was derived which relates the concentration-response relationship to time of reinfection patency. This model was used to estimate the in vivo MIC of chloroquine in the treatment of Plasmodium vivax malaria.
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Friedrich LR, Popovici J, Kim S, Dysoley L, Zimmerman PA, Menard D, Serre D. Complexity of Infection and Genetic Diversity in Cambodian Plasmodium vivax. PLoS Negl Trop Dis 2016; 10:e0004526. [PMID: 27018585 PMCID: PMC4809505 DOI: 10.1371/journal.pntd.0004526] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/18/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Plasmodium vivax is the most widely distributed human malaria parasite with 2.9 billion people living in endemic areas. Despite intensive malaria control efforts, the proportion of cases attributed to P. vivax is increasing in many countries. Genetic analyses of the parasite population and its dynamics could provide an assessment of the efficacy of control efforts, but, unfortunately, these studies are limited in P. vivax by the lack of informative markers and high-throughput genotyping methods. METHODOLOGY/PRINCIPAL FINDINGS We developed a sequencing-based assay to simultaneously genotype more than 100 SNPs and applied this approach to ~500 P. vivax-infected individuals recruited across nine locations in Cambodia between 2004 and 2013. Our analyses showed that the vast majority of infections are polyclonal (92%) and that P. vivax displays high genetic diversity in Cambodia without apparent geographic stratification. Interestingly, our analyses also revealed that the proportion of monoclonal infections significantly increased between 2004 and 2013, possibly suggesting that malaria control strategies in Cambodia may be successfully affecting the parasite population. CONCLUSIONS/SIGNIFICANCE Our findings demonstrate that this high-throughput genotyping assay is efficient in characterizing P. vivax diversity and can provide valuable insights to assess the efficacy of malaria elimination programs or to monitor the spread of specific parasites.
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Affiliation(s)
- Lindsey R. Friedrich
- Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States of America
| | - Jean Popovici
- Unite d’Epidemiologie Moleculaire, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Saorin Kim
- Unite d’Epidemiologie Moleculaire, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Lek Dysoley
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Peter A. Zimmerman
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Didier Menard
- Unite d’Epidemiologie Moleculaire, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - David Serre
- Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States of America
- * E-mail:
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9
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Reply to "Flow Cytometry for Antimalarial Drug Testing: More than Meets the Eye". J Clin Microbiol 2016; 54:818-9. [PMID: 26917460 DOI: 10.1128/jcm.03158-15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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10
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Wirjanata G, Handayuni I, Prayoga P, Apriyanti D, Chalfein F, Sebayang BF, Kho S, Noviyanti R, Kenangalem E, Campo B, Poespoprodjo JR, Price RN, Marfurt J. Quantification of Plasmodium ex vivo drug susceptibility by flow cytometry. Malar J 2015; 14:417. [PMID: 26498665 PMCID: PMC4619360 DOI: 10.1186/s12936-015-0940-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The emergence and spread of multidrug-resistant Plasmodium falciparum and Plasmodium vivax highlights the need for objective measures of ex vivo drug susceptibility. Flow cytometry (FC) has potential to provide a robust and rapid quantification of ex vivo parasite growth. METHODS Field isolates from Papua, Indonesia, underwent ex vivo drug susceptibility testing against chloroquine, amodiaquine, piperaquine, mefloquine, and artesunate. A single nucleic acid stain (i.e., hydroethidine (HE) for P. falciparum and SYBR Green I (SG) for P. vivax) was used to quantify infected red blood cells by FC-based signal detection. Data derived by FC were compared to standard quantification by light microscopy (LM). A subset of isolates was used to compare single and double staining techniques. RESULTS In total, 57 P. falciparum and 23 P. vivax field isolates were collected for ex vivo drug susceptibility testing. Reliable paired data between LM and FC was obtained for 88 % (295/334) of these assays. The median difference of derived IC50 values varied from -5.4 to 6.1 nM, associated with 0.83-1.23 fold change in IC50 values between LM and FC. In 15 assays (5.1 %), the derived difference of IC50 estimates was beyond the 95 % limits of agreement; in eleven assays (3.7 %), this was attributable to low parasite growth (final schizont count < 40 %), and in four assays (1.4 %) due to low initial parasitaemia at the start of assay (<2000 µl(-1)). In a subset of seven samples, LM, single and double staining FC techniques generated similar IC50 values. CONCLUSIONS A single staining FC-based assay using a portable cytometer provides a simple, fast and versatile platform for field surveillance of ex vivo drug susceptibility in clinical P. falciparum and P. vivax isolates.
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Affiliation(s)
- Grennady Wirjanata
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia. .,Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia.
| | - Irene Handayuni
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia.
| | - Pak Prayoga
- Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia.
| | - Dwi Apriyanti
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta, 10430, Indonesia.
| | - Ferryanto Chalfein
- Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia.
| | - Boni F Sebayang
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta, 10430, Indonesia.
| | - Steven Kho
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia.
| | - Rintis Noviyanti
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta, 10430, Indonesia.
| | - Enny Kenangalem
- Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia. .,District Health Authority, Timika, Papua, Indonesia.
| | - Brice Campo
- Medicines for Malaria Venture (MMV), 20 rte de Pré-Bois, PO Box 1826, 1215, Geneva 15, Switzerland.
| | - Jeanne Rini Poespoprodjo
- Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia. .,District Health Authority, Timika, Papua, Indonesia. .,Department of Paediatrics, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Indonesia.
| | - Ric N Price
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia. .,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
| | - Jutta Marfurt
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia.
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Woodrow CJ, Wangsing C, Sriprawat K, Christensen PR, Nosten F, Rénia L, Russell B, Malleret B. Comparison between Flow Cytometry, Microscopy, and Lactate Dehydrogenase-Based Enzyme-Linked Immunosorbent Assay for Plasmodium falciparum Drug Susceptibility Testing under Field Conditions. J Clin Microbiol 2015; 53:3296-303. [PMID: 26269616 PMCID: PMC4572553 DOI: 10.1128/jcm.01226-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/28/2015] [Indexed: 01/10/2023] Open
Abstract
Flow cytometry is an objective method for conducting in vitro antimalarial sensitivity assays with increasing potential for application in field sites. We examined in vitro susceptibility to seven anti-malarial drugs for 40 fresh P. falciparum field isolates via a flow cytometry method (FCM), a colorimetric LDH-based ELISA : DELI), and standard microscopic slide analysis of growth. For FCM, 184/280 (66%) assays met analytical acceptance criteria, compared to 166/280 (59%) for DELI. There was good agreement between FCM and microscopy, while DELI tended to produce higher half-maximal inhibition constants (IC50s) than FCM, with an overall bias of 2.2-fold (Bland-Altman comparison). Values for artesunate and dihydroartemisinin were most affected. Paradoxical increases in signal at very high concentrations of mefloquine and related compounds were more marked with the DELI assay, suggesting that off-target effects on LDH production may be responsible. Loss of FCM signal due to reinvasion or slow growth was observed in a small number of samples. These results extend previous work on use of flow cytometry to determine antimalarial susceptibility in terms of the number of samples, range of drugs, and comparison with other methods.
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Affiliation(s)
- Charles J Woodrow
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chirapat Wangsing
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Tak, Thailand
| | - Kanlaya Sriprawat
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Tak, Thailand
| | - Peter R Christensen
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Tak, Thailand
| | - Francois Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Tak, Thailand
| | - Laurent Rénia
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, Singapore
| | - Bruce Russell
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore, Singapore
| | - Benoît Malleret
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, Singapore Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore, Singapore
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12
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Cho JS, Russell B, Kosaisavee V, Zhang R, Colin Y, Bertrand O, Chandramohanadas R, Chu CS, Nosten F, Renia L, Malleret B. Unambiguous determination of Plasmodium vivax reticulocyte invasion by flow cytometry. Int J Parasitol 2015; 46:31-9. [PMID: 26385436 DOI: 10.1016/j.ijpara.2015.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 08/05/2015] [Accepted: 08/05/2015] [Indexed: 12/20/2022]
Abstract
The invasion of CD71+ reticulocytes by Plasmodium vivax is a crucial yet poorly characterised event. The application of flow cytometry to ex vivo invasion assays promises to facilitate the quantitative analysis of P. vivax reticulocyte invasion. However, current protocols suffer from a low level of sensitivity due to the absence of a particular design for P. vivax cell tropism. Importantly, merozoite invasion into contaminating red blood cells from the schizont inoculum (auto-invasion) may confound the analysis. Here we present a stable two-color flow cytometry assay for the accurate quantification of P. vivax merozoite invasion into intracellularly labelled CD71+ reticulocytes. Various enzymatic treatments, antibodies and invasion inhibitory molecules were used to successfully demonstrate the utility of this method. Fluorescent labelling of red blood cells did not affect the invasion and early intra-erythrocytic development of P. vivax. Importantly, this portable field assay allows for the economic usage of limited biological material (parasites and reticulocytes) and the intracellular labeling of the target cells reduces the need for highly purified schizont inoculums. This assay will facilitate the study of P. vivax merozoite biology and the testing of vaccine candidates against vivax malaria.
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Affiliation(s)
- Jee-Sun Cho
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, 5 Science Drive 2, Blk MD4, Level 3, Singapore 117597, Singapore; Singapore Immunology Network (SIgN), A(∗)STAR, 8A Biomedical Grove, Singapore 138648, Singapore
| | - Bruce Russell
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, 5 Science Drive 2, Blk MD4, Level 3, Singapore 117597, Singapore
| | - Varakorn Kosaisavee
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, 5 Science Drive 2, Blk MD4, Level 3, Singapore 117597, Singapore
| | - Rou Zhang
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, 5 Science Drive 2, Blk MD4, Level 3, Singapore 117597, Singapore
| | - Yves Colin
- INSERM, UMR_S1134, INTS 6, rue Alexandre Cabanel, 75739 Paris, France; Institut National de la Transfusion Sanguine, F-15013 Paris, France; Universite Paris 7-Denis Diderot, Sorbonne Paris cite, F-15-13 Paris, France
| | - Olivier Bertrand
- INSERM, UMR_S1134, INTS 6, rue Alexandre Cabanel, 75739 Paris, France; Institut National de la Transfusion Sanguine, F-15013 Paris, France; Universite Paris 7-Denis Diderot, Sorbonne Paris cite, F-15-13 Paris, France
| | - Rajesh Chandramohanadas
- Pillar of Engineering Product Development, Singapore University of Technology & Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Cindy S Chu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Road, Mae Sot 63110, Thailand; Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Old Road, Oxford OX3 7LJ, United Kingdom
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Road, Mae Sot 63110, Thailand; Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Old Road, Oxford OX3 7LJ, United Kingdom
| | - Laurent Renia
- Singapore Immunology Network (SIgN), A(∗)STAR, 8A Biomedical Grove, Singapore 138648, Singapore
| | - Benoit Malleret
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, 5 Science Drive 2, Blk MD4, Level 3, Singapore 117597, Singapore; Singapore Immunology Network (SIgN), A(∗)STAR, 8A Biomedical Grove, Singapore 138648, Singapore.
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Rebelo M, Tempera C, Fernandes JF, Grobusch MP, Hänscheid T. Assessing anti-malarial drug effects ex vivo using the haemozoin detection assay. Malar J 2015; 14:140. [PMID: 25879757 PMCID: PMC4393616 DOI: 10.1186/s12936-015-0657-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 03/17/2015] [Indexed: 11/20/2022] Open
Abstract
Background In vitro sensitivity assays are crucial to detect and monitor drug resistance. Plasmodium falciparum has developed resistance to almost all anti-malarial drugs. Although different in vitro drug assays are available, some of their inherent characteristics limit their application, especially in the field. A recently developed approach based on the flow cytometric detection of haemozoin (Hz) allowed reagent-free monitoring of parasite maturation and detection of drug effects in culture-adapted parasites. In this study, the set-up, performance and usefulness of this novel assay were investigated under field conditions in Gabon. Methods An existing flow cytometer (Cyflow Blue) was modified on site to detect light depolarization caused by Hz. Blood from malaria patients was incubated for 72 hrs with increasing concentrations of chloroquine, artesunate and artemisinin. The percentage of depolarizing red blood cells (RBC) was used as maturation indicator and measured at 24, 48 and 72 hrs of incubation to determine parasite growth and drug effects. Results The flow cytometer was easily adapted on site to detect light depolarization caused by Hz. Analysis of ex vivo cultures of parasites, obtained from blood samples of malaria patients, showed four different growth profiles. In 39/46 samples, 50% inhibitory concentrations (IC50) were successfully determined. IC50 values for chloroquine were higher than 200 nM in 70% of the samples, indicating the presence of chloroquine-resistant parasites. For artesunate and artemisinin, IC50 values ranged from 0.9 to 60 nM and from 2.2 nM to 124 nM, respectively, indicating fully sensitive parasites. Conclusion Flow cytometric detection of Hz allowed the detection of drug effects in blood samples from malaria patients, without using additional reagents or complex protocols. Adjustment of the initial parasitaemia was not required, which greatly simplifies the protocol, although it may lead to different IC50 values. Further investigation of set-up conditions of the Hz assay, as well as future studies in various settings should be performed to further determine the usefulness of this assay as a tool for rapid resistance testing in malaria-endemic countries.
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Affiliation(s)
- Maria Rebelo
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av Prof Egas Moniz, Lisbon, P-1649-028, Portugal. .,Centre de Recherches Médicales de Lambaréné - CERMEL, Albert Schweitzer Hospital, Lambaréné, Gabon.
| | - Carolina Tempera
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av Prof Egas Moniz, Lisbon, P-1649-028, Portugal.
| | - José F Fernandes
- Centre de Recherches Médicales de Lambaréné - CERMEL, Albert Schweitzer Hospital, Lambaréné, Gabon. .,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. .,Centre of Tropical Medicine and Travel Medicine, Amsterdam Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
| | - Martin P Grobusch
- Centre de Recherches Médicales de Lambaréné - CERMEL, Albert Schweitzer Hospital, Lambaréné, Gabon. .,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. .,Centre of Tropical Medicine and Travel Medicine, Amsterdam Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
| | - Thomas Hänscheid
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av Prof Egas Moniz, Lisbon, P-1649-028, Portugal. .,Centre de Recherches Médicales de Lambaréné - CERMEL, Albert Schweitzer Hospital, Lambaréné, Gabon. .,Instituto de Microbiologia, Faculdade de Medicina, Lisbon, Portugal.
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14
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Rebelo M, Tempera C, Bispo C, Andrade C, Gardner R, Shapiro HM, Hänscheid T. Light depolarization measurements in malaria: A new job for an old friend. Cytometry A 2015; 87:437-45. [PMID: 25808846 DOI: 10.1002/cyto.a.22659] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/28/2015] [Accepted: 02/27/2015] [Indexed: 12/15/2022]
Abstract
The use of flow cytometry in malaria research has increased over the last decade. Most approaches use nucleic acid stains to detect parasite DNA and RNA and require complex multi-color, multi-parameter analysis to reliably detect infected red blood cells (iRBCs). We recently described a novel and simpler approach to parasite detection based on flow cytometric measurement of scattered light depolarization caused by hemozoin (Hz), a pigment formed by parasite digestion of hemoglobin in iRBCs. Depolarization measurement by flow cytometry was described in 1987; however, patent issues restricted its use to a single manufacturer's hematology analyzers until 2009. Although we recently demonstrated that depolarization measurement of Hz, easily implemented on a bench top flow cytometer (Cyflow), provided useful information for malaria work, doubts regarding its application and utility remain in both the flow cytometry and malaria communities, at least in part because instrument manufacturers do not offer the option of measuring depolarized scatter. Under such circumstances, providing other researchers with guidance as to how to do this seemed to offer the most expeditious way to resolve the issue. We accordingly examined how several commercially available flow cytometers (CyFlow SL, MoFLo, Attune and Accuri C6) could be modified to detect depolarization due to the presence of free Hz on solution, or of Hz in leukocytes or erythrocytes from rodent or human blood. All were readily adapted, with substantially equivalent results obtained with lasers emitting over a wide wavelength range. Other instruments now available may also be modifiable for Hz measurement. Cytometric detection of Hz using depolarization is useful to study different aspects of malaria. Adding additional parameters, such as DNA content and base composition and RNA content, can demonstrably provide improved accuracy and sensitivity of parasite detection and characterization, allowing malaria researchers and eventually clinicians to benefit from cytometric technology.
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Affiliation(s)
- Maria Rebelo
- Molecular Microbiology and Infection Unit, Instituto De Medicina Molecular, Faculdade De Medicina, Lisbon, Portugal
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15
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An amidation/cyclization approach to the synthesis of N-hydroxyquinolinones and their biological evaluation as potential anti-plasmodial, anti-bacterial, and iron(II)-chelating agents. Bioorg Med Chem Lett 2015; 25:607-10. [DOI: 10.1016/j.bmcl.2014.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 11/22/2014] [Accepted: 12/05/2014] [Indexed: 11/24/2022]
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16
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Abdul-Ghani R, Al-Maktari MT, Al-Shibani LA, Allam AF. A better resolution for integrating methods for monitoring Plasmodium falciparum resistance to antimalarial drugs. Acta Trop 2014; 137:44-57. [PMID: 24801884 DOI: 10.1016/j.actatropica.2014.04.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/25/2014] [Accepted: 04/27/2014] [Indexed: 12/16/2022]
Abstract
Effective chemotherapy is the mainstay of malaria control. However, resistance of falciparum malaria to antimalarial drugs compromised the efforts to eliminate the disease and led to the resurgence of malaria epidemics. Three main approaches are used to monitor antimalarial drug efficacy and drug resistance; namely, in vivo trials, in vitro/ex vivo assays and molecular markers of drug resistance. Each approach has its implications of use as well as its advantages and drawbacks. Therefore, there is a need to use an integrated approach that would give the utmost effect to detect resistance as early as its emergence and to track it once spread. Such integration becomes increasingly needed in the era of artemisinin-based combination therapy as a forward action to deter resistance. The existence of regional and global networks for the standardization of methodology, provision of high quality reagents for the assessment of antimalarial drug resistance and dissemination of open-access data would help in approaching an integrated resistance surveillance system on a global scale.
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Suwanarusk R, Russell B, Ong A, Sriprawat K, Chu CS, PyaePhyo A, Malleret B, Nosten F, Renia L. Methylene blue inhibits the asexual development of vivax malaria parasites from a region of increasing chloroquine resistance. J Antimicrob Chemother 2014; 70:124-9. [PMID: 25150147 DOI: 10.1093/jac/dku326] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Methylene blue, once discarded due to its unsettling yet mild side effects, has now found a renewed place in the pharmacopoeia of modern medicine. The continued spread of drug-resistant Plasmodium vivax and Plasmodium falciparum has also led to a recent re-examination of methylene blue's potent antimalarial properties. Here we examine the ex vivo susceptibility profile of Plasmodium spp. isolates to methylene blue; the isolates were from a region on the Thai-Myanmar border where there are increasing rates of failure when treating vivax malaria with chloroquine. METHODS To do this we used a newly developed ex vivo susceptibility assay utilizing flow cytometry and a portable flow cytometer with a near-UV laser. RESULTS P. vivax (median methylene blue IC50 3.1 nM, IQR 1.7-4.3 nM) and P. falciparum (median methylene blue IC50 1.8 nM, IQR 1.6-2.3 nM) are susceptible to methylene blue treatment at physiologically relevant levels. Unfortunately, the addition of chloroquine to combination treatments with methylene blue significantly reduces the ex vivo effectiveness of this molecule. CONCLUSIONS Our data support further efforts to employ methylene blue as a safe, low-cost antimalarial to treat drug-resistant malaria.
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Affiliation(s)
- Rossarin Suwanarusk
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research, Biopolis, Singapore
| | - Bruce Russell
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - Alice Ong
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research, Biopolis, Singapore
| | | | - Cindy S Chu
- Shoklo Malaria Research Unit, Mae Sot, Tak Province, Thailand
| | - Aung PyaePhyo
- Shoklo Malaria Research Unit, Mae Sot, Tak Province, Thailand
| | - Benoit Malleret
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research, Biopolis, Singapore Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - François Nosten
- Shoklo Malaria Research Unit, Mae Sot, Tak Province, Thailand Mahidol-Oxford University Research Unit, Bangkok, Thailand Centre for Tropical Medicine, University of Oxford, Churchill Hospital, Oxford, UK
| | - Laurent Renia
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research, Biopolis, Singapore
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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.
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Affiliation(s)
| | | | | | - Steve A Ward
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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