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Basco LK. Cultivation of Asexual Intraerythrocytic Stages of Plasmodium falciparum. Pathogens 2023; 12:900. [PMID: 37513747 PMCID: PMC10384318 DOI: 10.3390/pathogens12070900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Successfully developed in 1976, the continuous in vitro culture of Plasmodium falciparum has many applications in the field of malaria research. It has become an important experimental model that directly uses a human pathogen responsible for a high prevalence of morbidity and mortality in many parts of the world and is a major source of biological material for immunological, biochemical, molecular, and pharmacological studies. Until present, the basic techniques described by Trager and Jensen and Haynes et al. remain unchanged in many malaria research laboratories. Nonetheless, different factors, including culture media, buffers, serum substitutes and supplements, sources of erythrocytes, and conditions of incubation (especially oxygen concentration), have been modified by different investigators to adapt the original technique in their laboratories or enhance the in vitro growth of the parasites. The possible effects and benefits of these modifications for the continuous cultivation of asexual intraerythrocytic stages of P. falciparum, as well as future challenges in developing a serum-free cultivation system and axenic cultures, are discussed.
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Affiliation(s)
- Leonardo K Basco
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique-Hôpitaux de Marseille (AP-HM), Service de Santé des Armées (SSA), Unité Mixte de Recherche (UMR) Vecteurs-Infections Tropicales et Méditerranéennes (VITROME), 13005 Marseille, France
- Institut Hospitalo-Universitaire-Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
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2
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Crispim M, Verdaguer IB, Silva SF, Katzin AM. Suitability of methods for Plasmodium falciparum cultivation in atmospheric air. Mem Inst Oswaldo Cruz 2022; 117:e210331. [PMID: 35857970 PMCID: PMC9296140 DOI: 10.1590/0074-02760210331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 06/09/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND One of the most controversial factors about malaria parasite culture is the
gaseous composition used. The most commonly used one consists of a mixture
poor in O2 and rich in CO2. OBJECTIVES The present study aimed to share standard methods from our research group
simplifying Plasmodium falciparum cultures by employing
atmospheric air (ATM) and reusable glass bottles under agitation. METHODS Here, it was compared the parasite viability, free oxygen in media, and drug
sensitivity between different strains and isolates maintained for long
periods under ATM or classic conditions. FINDINGS The oxygen concentration in media under ATM was slightly superior to that
observed in human blood and the media under the classic gaseous mixture.
However, ATM or the use of glass bottles did not affect parasitic
proliferation after several years of culture. Noticeably, the introduction
of ATM altered reversibly the efficacy of several antimalarials. This
influence was different between the strains and isolate. CONCLUSIONS ATM conditions and shaken flasks could be used as a standard method
condition for culture manutention since they do not differ greatly from
classical 5% O2 gas mixtures in terms of parasite proliferation
and do not impose non-reversible changes to P. falciparum
physiology.
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Affiliation(s)
- Marcell Crispim
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Parasitologia, São Paulo, SP, Brasil
| | - Ignasi Bofill Verdaguer
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Parasitologia, São Paulo, SP, Brasil
| | - Sofia Ferreira Silva
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Parasitologia, São Paulo, SP, Brasil
| | - Alejandro Miguel Katzin
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Parasitologia, São Paulo, SP, Brasil
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Ochora DO, Kakudidi EK, Namukobe J, Ipulet P, Wakoli DM, Okore W, Mwakio EW, Yeda RA, Cheruiyot AC, Juma DW, Andagalu B, Roth AL, Ogutu BR, Yenesew A, Akala HM. Synergism in Antiplasmodial Activities of Artemether and Lumefantrine in Combination with Securidaca longipedunculata Fresen (Polygalaceae). PLANTS (BASEL, SWITZERLAND) 2021; 11:47. [PMID: 35009051 PMCID: PMC8747340 DOI: 10.3390/plants11010047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 11/16/2022]
Abstract
Malaria is the most lethal parasitic disease in the world. The frequent emergence of resistance by malaria parasites to any drug is the hallmark of sustained malaria burden. Since the deployment of artemisinin-based combination therapies (ACTs) it is clear that for a sustained fight against malaria, drug combination is one of the strategies toward malaria elimination. In Sub-Saharan Africa where malaria prevalence is the highest, the identification of plants with a novel mechanism of action that is devoid of cross-resistance is a feasible strategy in drug combination therapy. Thus, artemether and lumefantrine were separately combined and tested with extracts of Securidaca longipedunculata, a plant widely used to treat malaria, at fixed extract-drug ratios of 4:1, 3:1, 1:1, 1:2, 1:3, and 1:4. These combinations were tested for antiplasmodial activity against three strains of Plasmodium falciparum (W2, D6, and DD2), and seven field isolates that were characterized for molecular and ex vivo drug resistance profiles. The mean sum of fifty-percent fractional inhibition concentration (FIC50) of each combination and singly was determined. Synergism was observed across all fixed doses when roots extracts were combined with artemether against D6 strain (FIC50 0.403 ± 0.068) and stems extract combined with lumefantrine against DD2 strain (FIC50 0.376 ± 0.096) as well as field isolates (FIC50 0.656 ± 0.067). Similarly, synergism was observed in all ratios when leaves extract were combined with lumefantrine against W2 strain (FIC50 0.456 ± 0.165). Synergism was observed in most combinations indicating the potential use of S. longipedunculata in combination with artemether and lumefantrine in combating resistance.
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Affiliation(s)
- Douglas O. Ochora
- Department of Plant Sciences, Microbiology & Biotechnology, College of Natural Sciences, Makerere University, Kampala P.O. Box 7062-10207, Uganda; (E.K.K.); (P.I.)
| | - Esezah K. Kakudidi
- Department of Plant Sciences, Microbiology & Biotechnology, College of Natural Sciences, Makerere University, Kampala P.O. Box 7062-10207, Uganda; (E.K.K.); (P.I.)
| | - Jane Namukobe
- Department of Chemistry, College of Natural Sciences, Makerere University, Kampala P.O. Box 7062-10207, Uganda;
| | - Perpetua Ipulet
- Department of Plant Sciences, Microbiology & Biotechnology, College of Natural Sciences, Makerere University, Kampala P.O. Box 7062-10207, Uganda; (E.K.K.); (P.I.)
| | - Dancan M. Wakoli
- Department of Biochemistry and Molecular Biology, Egerton University, Njoro P.O. Box 536-20115, Kenya;
- United States Army Medical Research Directorate-Kenya (USAMRD-K), Kenya Medical Research Institute (KEMRI)—Walter Reed Project, Kisumu, Kisumu P.O. Box 54-40100, Kenya;
| | - Winnie Okore
- United States Army Medical Research Directorate-Kenya (USAMRD-K), Kenya Medical Research Institute (KEMRI)—Walter Reed Project, Kisumu, Kisumu P.O. Box 54-40100, Kenya;
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno P.O. Box Private Bag-40105, Kenya; (E.W.M.); (R.A.Y.); (A.C.C.); (D.W.J.); (B.A.); (A.L.R.)
| | - Edwin W. Mwakio
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno P.O. Box Private Bag-40105, Kenya; (E.W.M.); (R.A.Y.); (A.C.C.); (D.W.J.); (B.A.); (A.L.R.)
| | - Redempthah A. Yeda
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno P.O. Box Private Bag-40105, Kenya; (E.W.M.); (R.A.Y.); (A.C.C.); (D.W.J.); (B.A.); (A.L.R.)
| | - Agnes C. Cheruiyot
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno P.O. Box Private Bag-40105, Kenya; (E.W.M.); (R.A.Y.); (A.C.C.); (D.W.J.); (B.A.); (A.L.R.)
| | - Dennis W. Juma
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno P.O. Box Private Bag-40105, Kenya; (E.W.M.); (R.A.Y.); (A.C.C.); (D.W.J.); (B.A.); (A.L.R.)
| | - Ben Andagalu
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno P.O. Box Private Bag-40105, Kenya; (E.W.M.); (R.A.Y.); (A.C.C.); (D.W.J.); (B.A.); (A.L.R.)
| | - Amanda L. Roth
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno P.O. Box Private Bag-40105, Kenya; (E.W.M.); (R.A.Y.); (A.C.C.); (D.W.J.); (B.A.); (A.L.R.)
| | - Bernhards R. Ogutu
- Centre for Clinical Research, Kenya Medical Research Institute (KEMRI), Kisumu P.O. Box 1578-40100, Kenya;
| | - Abiy Yenesew
- Department of Chemistry, University of Nairobi, Nairobi P.O. Box 30197-00100, Kenya;
| | - Hoseah M. Akala
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno P.O. Box Private Bag-40105, Kenya; (E.W.M.); (R.A.Y.); (A.C.C.); (D.W.J.); (B.A.); (A.L.R.)
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Compounds from the Medicines for Malaria Venture Box Inhibit In Vitro Growth of Babesia divergens, a Blood-Borne Parasite of Veterinary and Zoonotic Importance. Molecules 2021; 26:molecules26237118. [PMID: 34885700 PMCID: PMC8658764 DOI: 10.3390/molecules26237118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 11/17/2022] Open
Abstract
Babesiosis is an infectious disease with an empty drug pipeline. A search inside chemical libraries for novel potent antibabesial candidates may help fill such an empty drug pipeline. A total of 400 compounds (200 drug-like and 200 probe-like) from the Malaria Box were evaluated in the current study against the in vitro growth of Babesia divergens (B. divergens), a parasite of veterinary and zoonotic importance. Novel and more effective anti-B. divergens drugs than the traditionally used ones were identified. Seven compounds (four drug-like and three probe-like) revealed a highly inhibitory effect against the in vitro growth of B. divergens, with IC50s ≤ 10 nanomolar. Among these hits, MMV006913 exhibited an IC50 value of 1 nM IC50 and the highest selectivity index of 32,000. The atom pair fingerprint (APfp) analysis revealed that MMV006913 and MMV019124 showed maximum structural similarity (MSS) with atovaquone and diminazene aceturate (DA), and with DA and imidocarb dipropionate (ID), respectively. MMV665807 and MMV665850 showed MMS with each other and with ID. Of note, a high concentration (0.75 IC50) of MMV006913 caused additive inhibition of B. divergens growth when combined with DA at 0.75 or 0.50 IC50. The Medicines for Malaria Venture box is a treasure trove of anti-B. divergens candidates according to the obtained results.
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Slater L, Betson M, Ashraf S, Sargison N, Chaudhry U. Current methods for the detection of antimalarial drug resistance in Plasmodium parasites infecting humans. Acta Trop 2021; 216:105828. [PMID: 33465353 DOI: 10.1016/j.actatropica.2021.105828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/08/2021] [Accepted: 01/10/2021] [Indexed: 12/19/2022]
Abstract
Malaria is the world's deadliest parasitic disease. Great progress has been made in the fight against malaria over the past two decades, but this has recently begun to plateau, in part due to the global development of antimalarial drug resistance. The ability to track drug resistance is necessary to achieve progress in treatment, disease surveillance and epidemiology, which has prompted the development of advanced diagnostic methods. These new methods provide unprecedented access to information that can help to guide public health policies. Development of new technologies increases the potential for high throughput and reduced costs of diagnostic tests; improving the accessibility of tools to investigate the forces driving disease dynamics and, ultimately, clinical outcomes for malaria patients and public health. This literature review provides a summary of the methods currently available for the detection of antimalarial drug resistance from the examination of patients' blood samples. While no single method is perfect for every application, many of the newly developed methods give promise for more reliable and efficient characterisation of Plasmodium resistance in a range of settings. By exploiting the strengths of the tools available, we can develop a deeper understanding of the evolutionary and spatiotemporal dynamics of this disease. This will translate into more effective disease control, better-informed policy, and more timely and successful treatment for malaria patients.
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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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7
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Peric M, Pešić D, Alihodžić S, Fajdetić A, Herreros E, Gamo FJ, Angulo-Barturen I, Jiménez-Díaz MB, Ferrer-Bazaga S, Martínez MS, Gargallo-Viola D, Mathis A, Kessler A, Banjanac M, Padovan J, Bencetić Mihaljević V, Munic Kos V, Bukvić M, Eraković Haber V, Spaventi R. A novel class of fast-acting antimalarial agents: Substituted 15-membered azalides. Br J Pharmacol 2020; 178:363-377. [PMID: 33085774 PMCID: PMC9328652 DOI: 10.1111/bph.15292] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 09/01/2020] [Accepted: 10/08/2020] [Indexed: 12/18/2022] Open
Abstract
Background and Purpose Efficacy of current antimalarial treatments is declining as a result of increasing antimalarial drug resistance, so new and potent antimalarial drugs are urgently needed. Azithromycin, an azalide antibiotic, was found useful in malaria therapy, but its efficacy in humans is low. Experimental Approach Four compounds belonging to structurally different azalide classes were tested and their activities compared to azithromycin and chloroquine. in vitro evaluation included testing against sensitive and resistant Plasmodium falciparum, cytotoxicity against HepG2 cells, accumulation and retention in human erythrocytes, antibacterial activity, and mode of action studies (delayed death phenotype and haem polymerization). in vivo assessment enabled determination of pharmacokinetic profiles in mice, rats, dogs, and monkeys and in vivo efficacy in a humanized mouse model. Key Results Novel fast‐acting azalides were highly active in vitro against P. falciparum strains exhibiting various resistance patterns, including chloroquine‐resistant strains. Excellent antimalarial activity was confirmed in a P. falciparum murine model by strong inhibition of haemozoin‐containing trophozoites and quick clearance of parasites from the blood. Pharmacokinetic analysis revealed that compounds are metabolically stable and have moderate oral bioavailability, long half‐lives, low clearance, and substantial exposures, with blood cells as the preferred compartment, especially infected erythrocytes. Fast anti‐plasmodial action is achieved by the high accumulation into infected erythrocytes and interference with parasite haem polymerization, a mode of action different from slow‐acting azithromycin. Conclusion and Implications The hybrid derivatives described here represent excellent antimalarial drug candidates with the potential for clinical use in malaria therapy.
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Affiliation(s)
- Mihaela Peric
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Center for Translational and Clinical Research, Department for Intercellular Communication, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Dijana Pešić
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Sulejman Alihodžić
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Andrea Fajdetić
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Esperanza Herreros
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain.,Medicines for Malaria Venture, Geneva 15, Switzerland
| | - Francisco Javier Gamo
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain
| | - Iñigo Angulo-Barturen
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain.,The Art of Discovery, Bizkaia, Basque Country, Spain
| | - María Belén Jiménez-Díaz
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain.,The Art of Discovery, Bizkaia, Basque Country, Spain
| | - Santiago Ferrer-Bazaga
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain
| | - María S Martínez
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain
| | - Domingo Gargallo-Viola
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain.,ABAC Therapeutics, Barcelona, Spain
| | - Amanda Mathis
- GlaxoSmithKline, Research Triangle Park, North Carolina, USA.,BioCryst Pharmaceuticals, Durham, North Carolina, USA
| | - Albane Kessler
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain
| | - Mihailo Banjanac
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Jasna Padovan
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | | | - Vesna Munic Kos
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Mirjana Bukvić
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Vesna Eraković Haber
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Radan Spaventi
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Triadelta Partners Ltd, Zagreb, Croatia
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Rapid and quantitative antimalarial drug efficacy testing via the magneto-optical detection of hemozoin. Sci Rep 2020; 10:14025. [PMID: 32820190 PMCID: PMC7441145 DOI: 10.1038/s41598-020-70860-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 07/24/2020] [Indexed: 01/24/2023] Open
Abstract
Emergence of resistant Plasmodium species makes drug efficacy testing a crucial part of malaria control. Here we describe a novel assay for sensitive, fast and simple drug screening via the magneto-optical detection of hemozoin, a natural biomarker formed during the hemoglobin metabolism of Plasmodium species. By quantifying hemozoin production over the intraerythrocytic cycle, we reveal that hemozoin formation is already initiated by ~ 6–12 h old ring-stage parasites. We demonstrate that the new assay is capable of drug efficacy testing with incubation times as short as 6–10 h, using synchronized P. falciparum 3D7 cultures incubated with chloroquine, piperaquine and dihydroartemisinin. The determined 50% inhibitory concentrations agree well with values established by standard assays requiring significantly longer testing time. Accordingly, we conclude that magneto-optical hemozoin detection provides a practical approach for the quick assessment of drug effect with short incubation times, which may also facilitate stage-specific assessment of drug inhibitory effects.
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9
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Kulkeaw K, Ketprasit N, Tungtrongchitr A, Palasuwan D. A simple monochromatic flow cytometric assay for assessment of intraerythrocytic development of Plasmodium falciparum. Malar J 2020; 19:74. [PMID: 32070344 PMCID: PMC7027058 DOI: 10.1186/s12936-020-03156-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/09/2020] [Indexed: 11/12/2022] Open
Abstract
Background Gold standard microscopic examination of Plasmodium falciparum intraerythrocytic stage remains an important process for staging and enumerating parasitized erythrocytes in culture; however, microscopy is laborious and its accuracy is dependent upon the skill of the examiner. Methods In this study, ViSafe Green (VSG), which is a nucleic acid-binding fluorescent dye, was used for assessing in vitro development of P. falciparum using flow cytometry. Results Fluorescence intensity of VSG was found to depend on the developmental stage of parasites. Specifically, multiple-nuclei-containing schizonts were observed in the VSGhigh population, and growing trophozoites and ring-shaped forms were observed in the VSGintermediate and VSGlow populations. The efficacy of VSG-based assay was found to be comparable to the microscopic examination method, and it demonstrated an ability to detect as low as 0.001% of the parasitaemia estimated by Giemsa staining. Moreover, when applying VSG for anti-malarial drug test, it was able to observe the growth inhibitory effect of dihydroartemisinin, the front-line drug for malaria therapy. Conclusions Taken together, the results of this study suggest the VSG-based flow cytometric assay to be a simple and reliable assay for assessing P. falciparum malaria development in vitro.
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Affiliation(s)
- Kasem Kulkeaw
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2, Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand.
| | - Nutpakal Ketprasit
- Oxidation in Red Cell Disorders and Health Research Unit, Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, 154 Rama 1 Road, Pathumwan, Bangkok, 10330, Thailand
| | - Anchalee Tungtrongchitr
- Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2, Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand
| | - Duangdao Palasuwan
- Oxidation in Red Cell Disorders and Health Research Unit, Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, 154 Rama 1 Road, Pathumwan, Bangkok, 10330, Thailand.
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10
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Mohammadi S, Jafari B, Asgharian P, Martorell M, Sharifi-Rad J. Medicinal plants used in the treatment of Malaria: A key emphasis to Artemisia, Cinchona, Cryptolepis, and Tabebuia genera. Phytother Res 2020; 34:1556-1569. [PMID: 32022345 DOI: 10.1002/ptr.6628] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 12/14/2019] [Accepted: 01/14/2020] [Indexed: 01/30/2023]
Abstract
Malaria is one of the life-threatening parasitic diseases that is endemic in tropical areas. The increased prevalence of malaria due to drug resistance leads to a high incidence of mortality. Drug discovery based on natural products and secondary metabolites is considered as alternative approaches for antimalarial therapy. Herbal medicines have advantages over modern medicines, including fewer side effects, cost-effectiveness, and affordability encouraging the herbal-based drug discovery. Several naturally occurring, semisynthetic, and synthetic antimalarial medications are on the market. For example, chloroquine is a synthetic medication for antimalarial therapy derived from quinine. Moreover, artemisinin, and its derivative, artesunate with sesquiterpene lactone backbone, is an antimalarial agent originated from Artemisia annua L. A. annua traditionally has been used to detoxify blood and eliminate fever in China. Although the artemisinin-based combination therapy against malaria has shown exceptional responses, the limited medicinal options demand novel therapeutics. Furthermore, drug resistance is the cause in most cases, and new medications are proposed to overcome the resistance. In addition to conventional therapeutics, this review covers some important genera in this area, including Artemisia, Cinchona, Cryptolepis, and Tabebuia, whose antimalarial activities are finely verified.
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Affiliation(s)
- Samin Mohammadi
- Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Behzad Jafari
- Department of Medicinal Chemistry, Faculty of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran
| | - Parina Asgharian
- Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.,Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Miquel Martorell
- Department of Nutrition and Dietetics, Faculty of Pharmacy, University of Concepcion, Chile.,Unidad de Desarrollo Tecnológico (UDT), Universidad de Concepción, Chile
| | - Javad Sharifi-Rad
- Phytochemistry Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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11
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Rizk MA, El-Sayed SAES, Nassif M, Mosqueda J, Xuan X, Igarashi I. Assay methods for in vitro and in vivo anti-Babesia drug efficacy testing: Current progress, outlook, and challenges. Vet Parasitol 2019; 279:109013. [PMID: 32070899 DOI: 10.1016/j.vetpar.2019.109013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/10/2019] [Accepted: 12/12/2019] [Indexed: 02/06/2023]
Abstract
Absence of an effective high-throughput drug-screening system for Babesia parasites is considered one of the main causes for the presence of a wide gap in the treatment of animal babesiosis when compared with other hemoprotozoan diseases, such as malaria. Recently, a simple, accurate, and automatic fluorescence assay was established for large-scale anti-Babesia (B. bovis, B. bigemina, B. divergens, B. caballi and T. equi) drug screening. Such development will facilitate anti-Babesia drug discovery, especially in the post-genomic era, which will bring new chemotherapy targets with the completion of the Babesia genome sequencing project currently in progress. In this review, we present the current progress in the various assays for in vitro and in vivo anti-Babesia drug testing, as well as the challenges, highlighting new insights into the future of anti-Babesia drug screening.
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Affiliation(s)
- Mohamed Abdo Rizk
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan; Department of Internal Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Shimaa Abd El-Salam El-Sayed
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan; Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Medhat Nassif
- Department of Animal Medicine, Faculty of Veterinary Medicine, Kafrelsheikh University, Egypt
| | - Juan Mosqueda
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan; Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Avenida de las Ciencias s/n, 76230, Juriquilla, Querétaro, Mexico
| | - Xuenan Xuan
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan
| | - Ikuo Igarashi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan.
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12
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Zheng S, Loreto R, Smith P, Patterson A, Hughes D, Wang L. Specialist and Generalist Fungal Parasites Induce Distinct Biochemical Changes in the Mandible Muscles of Their Host. Int J Mol Sci 2019; 20:E4589. [PMID: 31533250 PMCID: PMC6769763 DOI: 10.3390/ijms20184589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 11/24/2022] Open
Abstract
Some parasites have evolved the ability to adaptively manipulate host behavior. One notable example is the fungus Ophiocordyceps unilateralis sensu lato, which has evolved the ability to alter the behavior of ants in ways that enable fungal transmission and lifecycle completion. Because host mandibles are affected by the fungi, we focused on understanding changes in the metabolites of muscles during behavioral modification. We used High-Performance Liquid Chromatography-Mass/Mass (HPLC-MS/MS) to detect the metabolite difference between controls and O. unilateralis-infected ants. There was a significant difference between the global metabolome of O. unilateralis-infected ants and healthy ants, while there was no significant difference between the Beauveria bassiana treatment ants group compared to the healthy ants. A total of 31 and 16 of metabolites were putatively identified from comparisons of healthy ants with O. unilateralis-infected ants and comparisons of B. bassiana with O. unilateralis-infected samples, respectively. This result indicates that the concentrations of sugars, purines, ergothioneine, and hypoxanthine were significantly increased in O. unilateralis-infected ants in comparison to healthy ants and B. bassiana-infected ants. This study provides a comprehensive metabolic approach for understanding the interactions, at the level of host muscles, between healthy ants and fungal parasites.
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Affiliation(s)
- Shanshan Zheng
- Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fuzhou 350002, China.
- College of Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.
| | - Raquel Loreto
- Center for Infectious Diseases Dynamics, Pennsylvania State University, University Park, PA 16802, USA.
- CAPES Foundation, Ministry of Education of Brazil, Brasilia 70040-020, DF, Brazil.
| | - Philip Smith
- Metabolomics Core Facility, Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA 16802, USA.
| | - Andrew Patterson
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA 16802, USA.
| | - David Hughes
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA.
| | - Liande Wang
- Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fuzhou 350002, China.
- College of Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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13
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Inducing controlled cell cycle arrest and re-entry during asexual proliferation of Plasmodium falciparum malaria parasites. Sci Rep 2018; 8:16581. [PMID: 30409996 PMCID: PMC6224408 DOI: 10.1038/s41598-018-34964-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/26/2018] [Indexed: 02/08/2023] Open
Abstract
The life cycle of the malaria parasite Plasmodium falciparum is tightly regulated, oscillating between stages of intense proliferation and quiescence. Cyclic 48-hour asexual replication of Plasmodium is markedly different from cell division in higher eukaryotes, and mechanistically poorly understood. Here, we report tight synchronisation of malaria parasites during the early phases of the cell cycle by exposure to DL-α-difluoromethylornithine (DFMO), which results in the depletion of polyamines. This induces an inescapable cell cycle arrest in G1 (~15 hours post-invasion) by blocking G1/S transition. Cell cycle-arrested parasites enter a quiescent G0-like state but, upon addition of exogenous polyamines, re-initiate their cell cycle. This ability to halt malaria parasites at a specific point in their cell cycle, and to subsequently trigger re-entry into the cell cycle, provides a valuable framework to investigate cell cycle regulation in these parasites. We subsequently used gene expression analyses to show that re-entry into the cell cycle involves expression of Ca2+-sensitive (cdpk4 and pk2) and mitotic kinases (nima and ark2), with deregulation of the pre-replicative complex associated with expression of pk2. Changes in gene expression could be driven through transcription factors MYB1 and two ApiAP2 family members. This new approach to parasite synchronisation therefore expands our currently limited toolkit to investigate cell cycle regulation in malaria parasites.
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Nsanzabana C, Djalle D, Guérin PJ, Ménard D, González IJ. Tools for surveillance of anti-malarial drug resistance: an assessment of the current landscape. Malar J 2018; 17:75. [PMID: 29422048 PMCID: PMC5806256 DOI: 10.1186/s12936-018-2185-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 01/10/2018] [Indexed: 12/12/2022] Open
Abstract
To limit the spread and impact of anti-malarial drug resistance and react accordingly, surveillance systems able to detect and track in real-time its emergence and spread need to be strengthened or in some places established. Currently, surveillance of anti-malarial drug resistance is done by any of three approaches: (1) in vivo studies to assess the efficacy of drugs in patients; (2) in vitro/ex vivo studies to evaluate parasite susceptibility to the drugs; and/or (3) molecular assays to detect validated gene mutations and/or gene copy number changes that are associated with drug resistance. These methods are complementary, as they evaluate different aspects of resistance; however, standardization of methods, especially for in vitro/ex vivo and molecular techniques, is lacking. The World Health Organization has developed a standard protocol for evaluating the efficacy of anti-malarial drugs, which is used by National Malaria Control Programmes to conduct their therapeutic efficacy studies. Regional networks, such as the East African Network for Monitoring Antimalarial Treatment and the Amazon Network for the Surveillance of Antimalarial Drug Resistance, have been set up to strengthen regional capacities for monitoring anti-malarial drug resistance. The Worldwide Antimalarial Resistance Network has been established to collate and provide global spatial and temporal trends information on the efficacy of anti-malarial drugs and resistance. While exchange of information across endemic countries is essential for monitoring anti-malarial resistance, sustainable funding for the surveillance and networking activities remains challenging. The technology landscape for molecular assays is progressing quite rapidly, and easy-to-use and affordable new techniques are becoming available. They also offer the advantage of high throughput analysis from a simple blood spots obtained from a finger prick. New technologies combined with the strengthening of national reference laboratories in malaria-endemic countries through standardized protocols and training plus the availability of a proficiency testing programme, would contribute to the improvement and sustainability of anti-malarial resistance surveillance networks worldwide.
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Affiliation(s)
| | - Djibrine Djalle
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | - Philippe J Guérin
- WorldWide Antimalarial Resistance Network, Oxford, UK.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Didier Ménard
- Unité Biologie des Interactions Hôte-Parasite, Institut Pasteur, Paris, France
| | - Iveth J González
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
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Hallyburton I, Grimaldi R, Woodland A, Baragaña B, Luksch T, Spinks D, James D, Leroy D, Waterson D, Fairlamb AH, Wyatt PG, Gilbert IH, Frearson JA. Screening a protein kinase inhibitor library against Plasmodium falciparum. Malar J 2017; 16:446. [PMID: 29115999 PMCID: PMC5678585 DOI: 10.1186/s12936-017-2085-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/23/2017] [Indexed: 11/29/2022] Open
Abstract
Background Protein kinases have been shown to be key drug targets, especially in the area of oncology. It is of interest to explore the possibilities of protein kinases as a potential target class in Plasmodium spp., the causative agents of malaria. However, protein kinase biology in malaria is still being investigated. Therefore, rather than assaying against individual protein kinases, a library of 4731 compounds with protein kinase inhibitor-like scaffolds was screened against the causative parasite, Plasmodium falciparum. This approach is more holistic and considers the whole kinome, making it possible to identify compounds that inhibit more than one P. falciparum protein kinase, or indeed other malaria targets. Results As a result of this screen, 9 active compound series were identified; further validation was carried out on 4 of these series, with 3 being progressed into hits to lead chemistry. The detailed evaluation of one of these series is described. Discussion This screening approach proved to be an effective way to identify series for further optimisation against malaria. Compound optimisation was carried out in the absence of knowledge of the molecular target. Some of the series had to be halted for various reasons. Mode of action studies to find the molecular target may be useful when problems prevent further chemical optimisation. Conclusions Progressible series were identified through phenotypic screening of a relatively small focused kinase scaffold chemical library.![]() Electronic supplementary material The online version of this article (10.1186/s12936-017-2085-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Irene Hallyburton
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Raffaella Grimaldi
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Andrew Woodland
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Beatriz Baragaña
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Torsten Luksch
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Daniel Spinks
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Daniel James
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Didier Leroy
- Medicines for Malaria Venture, Route de Pré-Bois 20, 1215, Geneva 15, Switzerland
| | - David Waterson
- Medicines for Malaria Venture, Route de Pré-Bois 20, 1215, Geneva 15, Switzerland
| | - Alan H Fairlamb
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Paul G Wyatt
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Ian H Gilbert
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.
| | - Julie A Frearson
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
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16
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Sinha S, Sarma P, Sehgal R, Medhi B. Development in Assay Methods for in Vitro Antimalarial Drug Efficacy Testing: A Systematic Review. Front Pharmacol 2017; 8:754. [PMID: 29123481 PMCID: PMC5662882 DOI: 10.3389/fphar.2017.00754] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 10/04/2017] [Indexed: 11/13/2022] Open
Abstract
The emergence and spread of drug resistance are the major challenges in malaria eradication mission. Besides various strategies laid down by World Health Organization, such as vector management, source reduction, early case detection, prompt treatment, and development of new diagnostics and vaccines, nevertheless the need for new and efficacious drugs against malaria has become a critical priority on the global malaria research agenda. At several screening stages, millions of compounds are screened (1,000–2,000,000 compounds per screening campaign), before pre-clinical trials to select optimum lead. Carrying out in vitro screening of antimalarials is very difficult as different assay methods are subject to numerous sources of variability across different laboratories around the globe. Despite this, in vitro screening is an essential part of antimalarial drug development as it enables to resource various confounding factors such as host immune response and drug–drug interaction. Therefore, in this article, we try to illustrate the basic necessity behind in vitro study and how new methods are developed and subsequently adopted for high-throughput antimalarial drug screening and its application in achieving the next level of in vitro screening based on the current approaches (such as stem cells).
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Affiliation(s)
- Shweta Sinha
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Phulen Sarma
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rakesh Sehgal
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Bikash Medhi
- Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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17
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Guanabenz repurposed as an antiparasitic with activity against acute and latent toxoplasmosis. Antimicrob Agents Chemother 2015; 59:6939-45. [PMID: 26303803 DOI: 10.1128/aac.01683-15] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 08/20/2015] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is a protozoan parasite that persists as a chronic infection. Toxoplasma evades immunity by forming tissue cysts, which reactivate to cause life-threatening disease during immune suppression. There is an urgent need to identify drugs capable of targeting these latent tissue cysts, which tend to form in the brain. We previously showed that translational control is critical during infections with both replicative and latent forms of Toxoplasma. Here we report that guanabenz, an FDA-approved drug that interferes with translational control, has antiparasitic activity against replicative stages of Toxoplasma and the related apicomplexan parasite Plasmodium falciparum (a malaria agent). We also found that inhibition of translational control interfered with tissue cyst biology in vitro. Toxoplasma bradyzoites present in these abnormal cysts were diminished and misconfigured, surrounded by empty space not seen in normal cysts. These findings prompted analysis of the efficacy of guanabenz in vivo by using established mouse models of acute and chronic toxoplasmosis. In addition to protecting mice from lethal doses of Toxoplasma, guanabenz has a remarkable ability to reduce the number of brain cysts in chronically infected mice. Our findings suggest that guanabenz can be repurposed into an effective antiparasitic with a unique ability to reduce tissue cysts in the brain.
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18
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Kumar S, Singh RK, Patial B, Goyal S, Bhardwaj TR. Recent advances in novel heterocyclic scaffolds for the treatment of drug-resistant malaria. J Enzyme Inhib Med Chem 2015; 31:173-86. [PMID: 25775094 DOI: 10.3109/14756366.2015.1016513] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Malaria is a major public health problem all over the world, particularly in tropical and subtropical countries due to the development of resistance and most deadly infection is caused by Plasmodium falciparum. There is a direct need for the discovery of new drugs with unique structures and mechanism of action to treat sensitive and drug-resistant strains of various plasmodia for radical cure of this disease. Traditional compounds such as quinine and related derivatives represent a major source for the development of new drugs. This review presents recent modifications of 4-aminoquinoline and 8-aminoquinolone rings as leads to novel active molecules which are under clinical trials. The review also encompasses the other heterocyclic compounds emerged as potential antimalarial agents with promising results such as acridinediones and acridinone analogues, pyridines and quinolones as antimalarials. Miscellaneous heterocyclics such as tetroxane derivatives, indole derivatives, imidazolopiperazine derivatives, biscationic choline-based compounds and polymer-linked combined antimalarial drugs are also discussed. At last brief introduction to heterocyclics in natural products is also reviewed. Most of them have been under clinical trials and found to be promising in the treatment of drug-resistant strains of Plasmodium and others can be explored for the same purpose.
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Affiliation(s)
- Sahil Kumar
- a Department of Pharmaceutical Chemistry , Indo-Soviet Friendship (I.S.F.) College of Pharmacy , Moga , Punjab , India .,b Faculty of Pharmacy , Punjab Technical University , Jalandhar, Kapurthala , India
| | - Rajesh K Singh
- c Department of Pharmaceutical Chemistry , Shivalik College of Pharmacy , Nangal, Dist. Rupnagar , Punjab , India , and
| | - Babita Patial
- a Department of Pharmaceutical Chemistry , Indo-Soviet Friendship (I.S.F.) College of Pharmacy , Moga , Punjab , India
| | - Sachin Goyal
- a Department of Pharmaceutical Chemistry , Indo-Soviet Friendship (I.S.F.) College of Pharmacy , Moga , Punjab , India
| | - T R Bhardwaj
- a Department of Pharmaceutical Chemistry , Indo-Soviet Friendship (I.S.F.) College of Pharmacy , Moga , Punjab , India .,d Department of Pharmaceutical Chemistry , University Institute of Pharmaceutical Sciences, Panjab University , Chandigarh , India
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19
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The rodent malaria lactate dehydrogenase assay provides a high throughput solution for in vivo vaccine studies. Parasitol Int 2015; 64:60-3. [PMID: 25701649 DOI: 10.1016/j.parint.2015.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/04/2015] [Accepted: 02/11/2015] [Indexed: 11/24/2022]
Abstract
Rodent malaria is a useful model for evaluating the efficacy of malaria vaccine candidates; however, labor-intensive microscopic parasite counting hampers the use of an in vivo parasite challenge in high-throughput screening. The measurement of malaria parasite lactate dehydrogenase (pLDH) activity, which is commonly used in the in vitro growth inhibition assay of Plasmodium falciparum, may be the cheapest and simplest alternative to microscopic parasite counting. However, the pLDH assay has not been applied in the in vivo rodent malaria model. Here, we showed that the pLDH assay is reliable and accurately determines parasitemia in the rodent malaria model. pLDH activity measured using a chromogenic substrate reflects the parasite number in the blood; it allows fast and easy assessment using a conventional microplate reader. To validate this approach, we synthesized recombinant PyMSP1-19 protein (rPyMSP1-19) using a wheat germ cell-free protein synthesis system and immunized mice with rPyMSP1-19. The antisera showed specific reactivity on the surface of the Plasmodium yoelii merozoite and immunized mice were protected against a lethal P. yoelii 17 XL challenge. The pLDH assay quickly and easily demonstrated a significant reduction of the parasite numbers in the immunized mice. Accordingly, the pLDH assay proved to be an efficient alternative to rodent malaria parasite counting, and may therefore accelerate in vivo vaccine candidate screening.
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20
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Webster WAJ, McFadden GI. From the genome to the phenome: tools to understand the basic biology of Plasmodium falciparum. J Eukaryot Microbiol 2014; 61:655-71. [PMID: 25227912 DOI: 10.1111/jeu.12176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.
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Affiliation(s)
- Wesley A J Webster
- Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Victoria, Australia; Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Melbourne, 3010, Victoria, Australia
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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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22
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Lotharius J, Gamo-Benito FJ, Angulo-Barturen I, Clark J, Connelly M, Ferrer-Bazaga S, Parkinson T, Viswanath P, Bandodkar B, Rautela N, Bharath S, Duffy S, Avery VM, Möhrle JJ, Guy RK, Wells T. Repositioning: the fast track to new anti-malarial medicines? Malar J 2014; 13:143. [PMID: 24731288 PMCID: PMC4021201 DOI: 10.1186/1475-2875-13-143] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/23/2014] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Repositioning of existing drugs has been suggested as a fast track for developing new anti-malarial agents. The compound libraries of GlaxoSmithKline (GSK), Pfizer and AstraZeneca (AZ) comprising drugs that have undergone clinical studies in other therapeutic areas, but not achieved approval, and a set of US Food and Drug Administration (FDA)-approved drugs and other bio-actives were tested against Plasmodium falciparum blood stages. METHODS Molecules were tested initially against erythrocytic co-cultures of P. falciparum to measure proliferation inhibition using one of the following methods: SYBR®I dye DNA staining assay (3D7, K1 or NF54 strains); [(3)H] hypoxanthine radioisotope incorporation assay (3D7 and 3D7A strain); or 4',6-diamidino-2-phenylindole (DAPI) DNA imaging assay (3D7 and Dd2 strains). After review of the available clinical pharmacokinetic and safety data, selected compounds with low μM activity and a suitable clinical profile were tested in vivo either in a Plasmodium berghei four-day test or in the P. falciparum Pf3D7(0087/N9) huSCID 'humanized' mouse model. RESULTS Of the compounds included in the GSK and Pfizer sets, 3.8% (9/238) had relevant in vitro anti-malarial activity while 6/100 compounds from the AZ candidate drug library were active. In comparison, around 0.6% (24/3,800) of the FDA-approved drugs and other bio-actives were active. After evaluation of available clinical data, four investigational drugs, active in vitro were tested in the P. falciparum humanized mouse model: UK-112,214 (PAF-H1 inhibitor), CEP-701 (protein kinase inhibitor), CEP-1347 (protein kinase inhibitor), and PSC-833 (p-glycoprotein inhibitor). Only UK-112,214 showed significant efficacy against P. falciparum in vivo, although at high doses (ED90 131.3 mg/kg [95% CI 112.3, 156.7]), and parasitaemia was still present 96 hours after treatment commencement. Of the six actives from the AZ library, two compounds (AZ-1 and AZ-3) were marginally efficacious in vivo in a P. berghei model. CONCLUSIONS Repositioning of existing therapeutics in malaria is an attractive proposal. Compounds active in vitro at μM concentrations were identified. However, therapeutic concentrations may not be effectively achieved in mice or humans because of poor bio-availability and/or safety concerns. Stringent safety requirements for anti-malarial drugs, given their widespread use in children, make this a challenging area in which to reposition therapy.
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Affiliation(s)
- Julie Lotharius
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 rte de Pré-Bois, 1215, Geneva 15, Switzerland
| | | | - Iñigo Angulo-Barturen
- Diseases of the Developing World Medicines Development Campus, GlaxoSmithKline, Madrid, Tres Cantos, Spain
| | - Julie Clark
- Department of Chemical Biology and Therapeutics, St Jude Children’s Research Hospital, Memphis, TN, USA
| | - Michele Connelly
- Department of Chemical Biology and Therapeutics, St Jude Children’s Research Hospital, Memphis, TN, USA
| | - Santiago Ferrer-Bazaga
- Diseases of the Developing World Medicines Development Campus, GlaxoSmithKline, Madrid, Tres Cantos, Spain
| | | | | | | | - Nikhil Rautela
- AstraZeneca India Pvt Ltd, Bellary Road, Hebbal, Bangalore, India
| | - Sowmya Bharath
- AstraZeneca India Pvt Ltd, Bellary Road, Hebbal, Bangalore, India
| | - Sandra Duffy
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - Vicky M Avery
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - Jörg J Möhrle
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 rte de Pré-Bois, 1215, Geneva 15, Switzerland
| | - R Kiplin Guy
- Department of Chemical Biology and Therapeutics, St Jude Children’s Research Hospital, Memphis, TN, USA
| | - Timothy Wells
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 rte de Pré-Bois, 1215, Geneva 15, Switzerland
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Sousa JC, Milner E, Carroll D, McCalmont W, Gardner S, Moon J, Johnson JD, Lee P, Auschwitz J, Roncal N, Caridha D, Tungteung A, Zeng Q, Reyes S, Smith B, Li Q, Kozar MP, Melendez V, Dow G. The use of a prodrug approach to minimize potential CNS exposure of next generation quinoline methanols while maintaining efficacy in in vivo animal models. Eur J Drug Metab Pharmacokinet 2014; 39:231-6. [PMID: 24705994 DOI: 10.1007/s13318-013-0162-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 12/04/2013] [Indexed: 11/25/2022]
Abstract
The use of mefloquine (MQ) for antimalarial treatment and prophylaxis has diminished largely in response to concerns about its neurologic side effects. An analog campaign designed to maintain the efficacy of MQ while minimizing blood-brain barrier (BBB) penetration has resulted in the synthesis of a prodrug with comparable-to-superior in vivo efficacy versus mefloquine in a P. berghei mouse model while exhibiting a sixfold reduction in CNS drug levels. The prodrug, WR319670, performed poorly compared to MQ in in vitro efficacy assays, but had promising in vitro permeability in an MDCK-MDR1 cell line BBB permeability screen. Its metabolite, WR308245, exhibited high predicted BBB penetration with excellent in vitro efficacy. Both WR319670 and WR308245 cured 5/5 animals in separate in vivo efficacy studies. The in vivo efficacy of WR319670 was thought to be due to the formation of a more active metabolite, specifically WR308245. This was supported by pharmacokinetics studies in non-infected mice, which showed that both IV and oral administration of WR319670 produced essentially identical levels of WR319670 and WR308245 in both plasma and brain samples at all time points. In these studies, the levels of WR308245 in the brain were 1/4 and 1/6 that of MQ in similar IV and oral studies, respectively. These data show that the use of WR319670 as an antimalarial prodrug was able to maintain efficacy in in vivo efficacy screens, while significantly lowering overall penetration of drug and metabolites across the BBB.
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Affiliation(s)
- Jason C Sousa
- Walter Reed Army Institute of Research, Silver Spring, MD, 20910, USA,
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Mata-Cantero L, Lafuente MJ, Sanz L, Rodriguez MS. Magnetic isolation of Plasmodium falciparum schizonts iRBCs to generate a high parasitaemia and synchronized in vitro culture. Malar J 2014; 13:112. [PMID: 24655321 PMCID: PMC3994429 DOI: 10.1186/1475-2875-13-112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 03/14/2014] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The establishment of methods for an in vitro continuous culture of Plasmodium falciparum is essential for gaining knowledge into its biology and for the development of new treatments. Previously, several techniques have been used to synchronize, enrich and concentrate P. falciparum, although obtaining cultures with high parasitaemia continues being a challenging process. Current methods produce high parasitaemia levels of synchronized P. falciparum cultures by frequent changes of culture medium or reducing the haematocrit. However, these methods are time consuming and sometimes lead to the loss of synchrony. METHODS A procedure that combines Percoll and sorbitol treatments, the use of magnetic columns, and the optimization of the in vitro culture conditions to reach high parasitaemia levels for synchronized Plasmodium falciparum cultures is described. RESULTS A new procedure has been established using P. falciparum 3D7, combining previous reported methodologies to achieve in vitro parasite cultures that reach parasitaemia up to 40% at any intra-erythrocytic stage. High parasitaemia levels are obtained only one day after magnetic column purification without compromising the parasite viability and synchrony. CONCLUSIONS The described procedure allows obtaining a large scale synchronized parasite culture at a high parasitaemia with less manipulations than other methods previously described.
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Affiliation(s)
- Lydia Mata-Cantero
- Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
- Proteomics Unit, CICbioGUNE Ed. 801A Parque Tecnológico de Bizkaia, 48160 Derio, Spain
| | - Maria J Lafuente
- Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Laura Sanz
- Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Manuel S Rodriguez
- Proteomics Unit, CICbioGUNE Ed. 801A Parque Tecnológico de Bizkaia, 48160 Derio, Spain
- Ubiquitylation and Cancer Molecular Biology, Inbiomed, Mikeletegi 81, 20009 San Sebastian, Spain
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Expression of the essential Kinase PfCDPK1 from Plasmodium falciparum in Toxoplasma gondii facilitates the discovery of novel antimalarial drugs. Antimicrob Agents Chemother 2014; 58:2598-607. [PMID: 24550330 DOI: 10.1128/aac.02261-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We have previously shown that genetic disruption of Toxoplasma gondii calcium-dependent protein kinase 3 (TgCDPK3) affects calcium ionophore-induced egress. We examined whether Plasmodium falciparum CDPK1 (PfCDPK1), the closest homolog of TgCDPK3 in the malaria parasite P. falciparum, could complement a TgCDPK3 mutant strain. PfCDPK1 is essential and plays critical roles in merozoite development, motility, and secretion. We show that expression of PfCDPK1 in the TgCDPK3 mutant strain rescues the egress defect. This phenotypic complementation requires the localization of PfCDPK1 to the plasma membrane and kinase activity. Interestingly, PfCDPK1-expressing Toxoplasma becomes more sensitive to egress inhibition by purfalcamine, a potent inhibitor of PfCDPK1 with low activity against TgCDPK3. Based on this result, we tested eight small molecules previously determined to inhibit the kinase activity of recombinant PfCDPK1 for their abilities to inhibit ionophore-induced egress in the PfCDPK1-expressing strain. While two of these chemicals did not inhibit egress, we found that six drugs affected this process selectively in PfCDPK1-expressing Toxoplasma. Using mutant versions of PfCDPK1 and TgCDPK3, we show that the selectivities of dasatinib and PLX-4720 are regulated by the gatekeeper residue in the ATP binding site. Importantly, we have confirmed that the three most potent inhibitors of egress in the PfCDPK1-expressing strain effectively kill P. falciparum. Thus, we have established and validated a recombinant strain of Toxoplasma that can be used as a surrogate for the discovery and analysis of PfCDPK1-specific inhibitors that can be developed as antimalarials.
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Kerubo LO, Midiwo JO, Derese S, Langat MK, Akala HM, Waters NC, Peter M, Heydenreich M. Antiplasmodial Activity of Compounds from the Surface Exudates of Senecio roseiflorus. Nat Prod Commun 2013. [DOI: 10.1177/1934578x1300800210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
From the surface exudates of Senecio roseiflorus fourteen known methylated flavonoids and one phenol were isolated and characterized. The structures of these compounds were determined on the basis of their spectroscopic analysis. The surface exudate and the flavonoids isolated showed moderate to good antiplasmodial activity with 5,4′-dihydroxy-7-dimethoxyflavanone having the highest activity against chloroquine-sensitive (D6) and resistant (W2) strains of Plasmodium falciparum, with IC50 values of 3.2 ± 0.8 and 4.4 ± 0.01 μg/mL respectively.
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Affiliation(s)
| | - Jacob Ogweno Midiwo
- Department of Chemistry, Nairobi University, P Bag 30197-00100, Nairobi, Kenya
| | - Solomon Derese
- Department of Chemistry, Nairobi University, P Bag 30197-00100, Nairobi, Kenya
| | - Moses K. Langat
- Department of Chemistry, FEPS, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom
| | - Hosea M. Akala
- United States Army Medical Research Unit-Kenya, Walter Reed Project, Kisumu, MRU 64109, APO, AE 09831-4109, USA
| | - Norman C. Waters
- United States Army Medical Research Unit-Kenya, Walter Reed Project, Kisumu, MRU 64109, APO, AE 09831-4109, USA
| | - Martin Peter
- Institut für Chemie, Potsdam Universität, P Bag 60 15 53, D-14415 Potsdam, Germany
| | - Matthias Heydenreich
- Institut für Chemie, Potsdam Universität, P Bag 60 15 53, D-14415 Potsdam, Germany
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Murray V, Campbell HM, Gero AM. Plasmodium falciparum: The potential of the cancer chemotherapeutic agent cisplatin and its analogues as anti-malarials. Exp Parasitol 2012; 132:440-3. [DOI: 10.1016/j.exppara.2012.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 09/06/2012] [Accepted: 09/10/2012] [Indexed: 10/27/2022]
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Identification and validation of tetracyclic benzothiazepines as Plasmodium falciparum cytochrome bc1 inhibitors. ACTA ACUST UNITED AC 2012; 18:1602-10. [PMID: 22195562 DOI: 10.1016/j.chembiol.2011.09.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/01/2011] [Accepted: 09/08/2011] [Indexed: 11/22/2022]
Abstract
Here we report the discovery of tetracyclic benzothiazepines (BTZs) as highly potent and selective antimalarials along with the identification of the Plasmodium falciparum cytochrome bc(1) complex as the primary functional target of this novel compound class. Investigation of the structure activity relationship within this previously unexplored chemical scaffold has yielded inhibitors with low nanomolar activity. A combined approach employing genetically modified parasites, biochemical profiling, and resistance selection validated inhibition of cytochrome bc(1) activity, an essential component of the parasite respiratory chain and target of the widely used antimalarial drug atovaquone, as the mode of action of this novel compound class. Resistance to atovaquone is eroding the efficacy of this widely used antimalarial drug. Intriguingly, BTZ-based inhibitors retain activity against atovaquone resistant parasites, suggesting this chemical class may provide an alternative to atovaquone in combination therapy.
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Abstract
Malaria continues to have a significant impact on the health of the developing world. Efforts to combat this disease now focus on combination therapy in order to stem the emergence of resistant parasites. Continued efforts are needed to discover and develop new agents for use in combination antimalarial regimens. MK-4815 is a small molecule with antimalarial activity that was identified from a large pharmaceutical compound collection using a semiautomated version of a well-established in vitro assay for the erythrocytic stages of Plasmodium falciparum. In vitro studies indicate that the compound selectively accumulates in infected red blood cells and is most effective against the metabolically active late trophozoite/early schizont stages. A variety of drug-resistant field isolates of P. falciparum were found to be as sensitive to MK-4815 as the wild-type lines. MK-4815 is orally active in a P. berghei mouse model of acute malaria. In this model, where untreated animals succumb to infection 10 to 12 days postinfection, MK-4815 was completely curative when given as a single dose of 50 mg/kg, 2 doses of 25 mg/kg, or 4.5 doses of 12.5 mg/kg. In pharmacokinetic studies with mice and rhesus monkeys, MK-4815 demonstrated oral bioavailability and low clearance. In addition, MK-4815 is inexpensive to synthesize, an important characteristic for providing affordable antimalaria therapy to the developing world. The attractive biological and pharmaceutical profile of MK-4815 demonstrates its potential for use in combination with other agents in the fight against malaria.
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Zhu S, Chandrashekar G, Meng L, Robinson K, Chatterji D. Febrifugine analogue compounds: synthesis and antimalarial evaluation. Bioorg Med Chem 2011; 20:927-32. [PMID: 22182577 DOI: 10.1016/j.bmc.2011.11.053] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/16/2011] [Accepted: 11/23/2011] [Indexed: 10/14/2022]
Abstract
Febrifugine is an alkaloid isolated from Dichroa febrifuga Lour as the active component against Plasmodium falciparum, but exhibits toxic side effects. In this study novel febrifugine analogues were designed and efficiently synthesized. New compounds underwent efficacy and toxicity evaluation. Some compounds are much less toxic than the natural product febrifugine and existing antimalarial drugs and are expected to possess wide therapeutic windows. In Aotus monkeys infected with the chloroquine resistant FVO strain of P. falciparum, one interesting compound possesses a 50% curative dose of 2mg/kg/day and a 100% curative dose of 8 mg/kg/day. These compounds, as well as the underlying design rationale, may find usefulness in the discovery and development of new antimalarial drugs.
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Affiliation(s)
- Shuren Zhu
- Radix Pharmaceuticals, Inc., 20271 Goldenrod Lane, Suite 2035, Germantown, MD 20876, USA.
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31
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Phenotypic and genotypic analysis of in vitro-selected artemisinin-resistant progeny of Plasmodium falciparum. Antimicrob Agents Chemother 2011; 56:302-14. [PMID: 22083467 DOI: 10.1128/aac.05540-11] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Emergence of artemisinin resistance in Cambodia highlights the importance of characterizing resistance to this class of drugs. Previously, intermediate levels of resistance in Plasmodium falciparum were generated in vitro for artelinic acid (AL) and artemisinin (QHS). Here we expanded on earlier selection efforts to produce levels of clinically relevant concentrations, and the resulting lines were characterized genotypically and phenotypically. Recrudescence assays determined the ability of resistant and parent lines to recover following exposure to clinically relevant levels of drugs. Interestingly, the parent clone (D6) tolerated up to 1,500 ng/ml QHS, but the resistant parasite, D6.QHS340×3, recovered following exposure to 2,400 ng/ml QHS. Resistant D6, W2, and TM91c235 parasites all exhibited elevated 50% inhibitory concentrations (IC(50)s) to multiple artemisinin drugs, with >3-fold resistance to QHS and AL; however, the degree of resistance obtained with standard methods was remarkably less than expected for parasite lines that recovered from 2,400-ng/ml drug pressure. A novel assay format with radiolabeled hypoxanthine demonstrated a greater degree of resistance in vitro than the standard SYBR green method. Analysis of merozoite number in resistant parasites found D6 and TM91c235 resistant progeny had significantly fewer merozoites than parent strains, whereas W2 resistant progeny had significantly more. Amplification of pfmdr1 increased proportionately to the increased drug levels tolerated by W2 and TM91c235, but not in resistant D6. In summary, we define the artemisinin resistance phenotype as a decrease in susceptibility to artemisinins along with the ability to recover from drug-induced dormancy following supraclinical concentrations of the drug.
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32
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Zhang L, Sathunuru R, Caridha D, Pybus B, O’Neil MT, Kozar MP, Lin AJ. Antimalarial Activities of New Guanidylimidazole and Guanidylimidazoline Derivatives. J Med Chem 2011; 54:6634-46. [PMID: 21848332 DOI: 10.1021/jm200503s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Liang Zhang
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Ramadas Sathunuru
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Diana Caridha
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Brandon Pybus
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Michael T. O’Neil
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Michael P. Kozar
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Ai J. Lin
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
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Liu X, Wang X, Li Q, Kozar MP, Melendez V, O’Neil MT, Lin AJ. Synthesis and Antimalarial Activity of 2-Guanidino-4-oxoimidazoline Derivatives. J Med Chem 2011; 54:4523-35. [DOI: 10.1021/jm200111g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xianjun Liu
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Xihong Wang
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Qigui Li
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Michael P. Kozar
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Victor Melendez
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Michael T. O’Neil
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
| | - Ai J. Lin
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, Maryland 20910, United States
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34
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Zhang L, Sathunuru R, Luong T, Melendez V, Kozar MP, Lin AJ. New imidazolidinedione derivatives as antimalarial agents. Bioorg Med Chem 2011; 19:1541-9. [DOI: 10.1016/j.bmc.2010.12.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 12/07/2010] [Accepted: 12/13/2010] [Indexed: 11/30/2022]
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Shiraki H, Kozar MP, Melendez V, Hudson TH, Ohrt C, Magill AJ, Lin AJ. Antimalarial activity of novel 5-aryl-8-aminoquinoline derivatives. J Med Chem 2010; 54:131-42. [PMID: 21141892 DOI: 10.1021/jm100911f] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In an attempt to separate the antimalarial activity of tafenoquine (3) from its hemolytic side effects in glucose-6-phosphate dehydrogenase (G6PD) deficiency patients, a series of 5-aryl-8-aminoquinoline derivatives was prepared and assessed for antimalarial activities. The new compounds were found metabolically stable in human and mouse microsomal preparations, with t(1/2) > 60 min, and were equal to or more potent than primaquine (2) and 3 against Plasmodium falciparum cell growth. The new agents were more active against the chloroquine (CQ) resistant clone than to the CQ-sensitive clone. Analogues with electron donating groups showed better activity than those with electron withdrawing substituents. Compounds 4bc, 4bd, and 4be showed comparable therapeutic index (TI) to that of 2 and 3, with TI ranging from 5 to 8 based on IC(50) data. The new compounds showed no significant causal prophylactic activity in mice infected with Plasmodium berghei sporozoites, but are substantially less toxic than 2 and 3 in mouse tests.
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Affiliation(s)
- Hiroaki Shiraki
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States
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36
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Reilly Ayala HB, Wacker MA, Siwo G, Ferdig MT. Quantitative trait loci mapping reveals candidate pathways regulating cell cycle duration in Plasmodium falciparum. BMC Genomics 2010; 11:577. [PMID: 20955606 PMCID: PMC3091725 DOI: 10.1186/1471-2164-11-577] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Accepted: 10/18/2010] [Indexed: 11/24/2022] Open
Abstract
Background Elevated parasite biomass in the human red blood cells can lead to increased malaria morbidity. The genes and mechanisms regulating growth and development of Plasmodium falciparum through its erythrocytic cycle are not well understood. We previously showed that strains HB3 and Dd2 diverge in their proliferation rates, and here use quantitative trait loci mapping in 34 progeny from a cross between these parent clones along with integrative bioinformatics to identify genetic loci and candidate genes that control divergences in cell cycle duration. Results Genetic mapping of cell cycle duration revealed a four-locus genetic model, including a major genetic effect on chromosome 12, which accounts for 75% of the inherited phenotype variation. These QTL span 165 genes, the majority of which have no predicted function based on homology. We present a method to systematically prioritize candidate genes using the extensive sequence and transcriptional information available for the parent lines. Putative functions were assigned to the prioritized genes based on protein interaction networks and expression eQTL from our earlier study. DNA metabolism or antigenic variation functional categories were enriched among our prioritized candidate genes. Genes were then analyzed to determine if they interact with cyclins or other proteins known to be involved in the regulation of cell cycle. Conclusions We show that the divergent proliferation rate between a drug resistant and drug sensitive parent clone is under genetic regulation and is segregating as a complex trait in 34 progeny. We map a major locus along with additional secondary effects, and use the wealth of genome data to identify key candidate genes. Of particular interest are a nucleosome assembly protein (PFL0185c), a Zinc finger transcription factor (PFL0465c) both on chromosome 12 and a ribosomal protein L7Ae-related on chromosome 4 (PFD0960c).
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Arnot DE, Ronander E, Bengtsson DC. The progression of the intra-erythrocytic cell cycle of Plasmodium falciparum and the role of the centriolar plaques in asynchronous mitotic division during schizogony. Int J Parasitol 2010; 41:71-80. [PMID: 20816844 DOI: 10.1016/j.ijpara.2010.07.012] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 07/22/2010] [Accepted: 07/23/2010] [Indexed: 12/11/2022]
Abstract
The cell division cycle and mitosis of intra-erythrocytic (IE) Plasmodium falciparum are poorly understood aspects of parasite development which affect malaria molecular pathogenesis. Specifically, the timing of the multiple gap (G), DNA synthesis (S) and chromosome separation (M) phases of parasite mitosis are not well defined, nor whether genome divisions are immediately followed by cleavage of the nuclear envelope. Curiously, daughter merozoite numbers do not follow the geometric expansion expected from equal numbers of binary divisions, an outcome difficult to explain using the standard model of cell cycle regulation. Using controlled synchronisation techniques, confocal microscopy to visualise key organelles and fluorescence in situ hybridization (FISH) to follow the movements and replication of genes and telomeres, we have re-analysed the timing and progression of mitotic events. The asynchronous duplications of the P. falciparum centrosome equivalents, the centriolar plaques, are established and these are correlated with chromosome and nuclear divisions in a new model of P. falciparum schizogony. Our results improve the resolution of the cell cycle and its phases during P. falciparum IE development, showing that asynchronous, independent nuclear division occurs during schizogony, with the centriolar plaques playing a major role in regulating mitotic progression.
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Affiliation(s)
- David E Arnot
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, 1014 København K, Denmark.
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Pallavi R, Roy N, Nageshan RK, Talukdar P, Pavithra SR, Reddy R, Venketesh S, Kumar R, Gupta AK, Singh RK, Yadav SC, Tatu U. Heat shock protein 90 as a drug target against protozoan infections: biochemical characterization of HSP90 from Plasmodium falciparum and Trypanosoma evansi and evaluation of its inhibitor as a candidate drug. J Biol Chem 2010; 285:37964-75. [PMID: 20837488 DOI: 10.1074/jbc.m110.155317] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Using a pharmacological inhibitor of Hsp90 in cultured malarial parasite, we have previously implicated Plasmodium falciparum Hsp90 (PfHsp90) as a drug target against malaria. In this study, we have biochemically characterized PfHsp90 in terms of its ATPase activity and interaction with its inhibitor geldanamycin (GA) and evaluated its potential as a drug target in a preclinical mouse model of malaria. In addition, we have explored the potential of Hsp90 inhibitors as drugs for the treatment of Trypanosoma infection in animals. Our studies with full-length PfHsp90 showed it to have the highest ATPase activity of all known Hsp90s; its ATPase activity was 6 times higher than that of human Hsp90. Also, GA brought about more robust inhibition of PfHsp90 ATPase activity as compared with human Hsp90. Mass spectrometric analysis of PfHsp90 expressed in P. falciparum identified a site of acetylation that overlapped with Aha1 and p23 binding domain, suggesting its role in modulating Hsp90 multichaperone complex assembly. Indeed, treatment of P. falciparum cultures with a histone deacetylase inhibitor resulted in a partial dissociation of PfHsp90 complex. Furthermore, we found a well known, semisynthetic Hsp90 inhibitor, namely 17-(allylamino)-17-demethoxygeldanamycin, to be effective in attenuating parasite growth and prolonging survival in a mouse model of malaria. We also characterized GA binding to Hsp90 from another protozoan parasite, namely Trypanosoma evansi. We found 17-(allylamino)-17-demethoxygeldanamycin to potently inhibit T. evansi growth in a mouse model of trypanosomiasis. In all, our biochemical characterization, drug interaction, and animal studies supported Hsp90 as a drug target and its inhibitor as a potential drug against protozoan diseases.
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Affiliation(s)
- Rani Pallavi
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
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Ijaz F, Ahmad N, Ahmad I, ul Haq A, Wang F. Two new anti-plasmodial flavonoid glycosides from Duranta repens. J Enzyme Inhib Med Chem 2010; 25:773-8. [PMID: 20565340 DOI: 10.3109/14756360903433365] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The CHCl(3)-soluble fraction of the whole plant of Duranta repens showed anti-plasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum, with IC(50) values of 8.5 ± 0.9 and 10.2 ± 1.5 μg/mL, respectively. From this fraction, two new flavonoid glycosides, 7-O-α-d-glucopyranosyl-3,4'-dihydroxy-3'-(4-hydroxy-3-methylbutyl)-5,6-dimethoxyflavone (1) and 7-O-α-d-glucopyranosyl(6'''-p-hydroxcinnamoyl)-3,4'-dihydroxy-3'-(4-hydroxy-3-methylbutyl)-5,6-dimethoxyflavone (2), along with five known flavonoids, 3,7,4'-trihydroxy-3'-(4-hydroxy-3-methylbutyl)-5,6-dimethoxyflavone (3), 3,7-dihydroxy-3'-(4-hydroxy-3-methylbutyl)-5,6,4'-trimethoxyflavone (4), 5,7-dihydroxy-3'-(2-hydroxy-3-methyl-3-butenyl)-3,6,4'-trimethoxyflavone (5), 3,7-dihydroxy-3'-(2-hydroxy-3-methyl-3-buten-yl)-5,6,4'-trimethoxyflavone (6), and 7-O-α-d-glucopyranosyl-3,5-dihydroxy-3'-(4''-acetoxy-3''-methylbutyl)-6,4'-dimethoxyflavone (7), have been isolated as anti-plasmodial principles. Their structures were deduced by spectroscopic analysis including 1D and 2D NMR techniques. The compounds (1-7) showed potent anti-plasmodial activities against D6 and W2 strains of Plasmodium falciparum, with IC(50) values in the range of 5.2-13.5 μM and 5.9-13.1 μM, respectively.
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Affiliation(s)
- Fozia Ijaz
- Kohat Institute of Medical Sciences, Kohat University of Science and Technology, Kohat, N.W.F.P., Pakistan
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40
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Synthesis and evaluation of 4-quinazolinone compounds as potential antimalarial agents. Eur J Med Chem 2010; 45:3864-9. [PMID: 20538379 DOI: 10.1016/j.ejmech.2010.05.040] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 05/14/2010] [Accepted: 05/18/2010] [Indexed: 11/21/2022]
Abstract
Febrifugine is an alkaloid isolated from Dichroa febrifuga as the active component against Plasmodium falciparum. Adverse side effects have precluded febrifugine as a potential clinical drug. As part of an ongoing malaria chemotherapy project, novel febrifugine analogues were designed and synthesized. Lower toxicity of these newly designed compounds was achieved by reducing or eliminating the tendency to form chemically reactive and toxic intermediates. New compounds possess excellent in vivo antimalarial activity and most of them become less toxic than the natural product febrifugine. Some of the compounds possess a therapeutic index over ten times superior to that of febrifugine and the commonly used antimalarial drug chloroquine. These compounds, as well as the underlying design rationale, may find usefulness in the discovery and development of new antimalarial drugs.
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41
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Ochieng CO, Ogweno Mid J, Okinda Owu P. Anti-Plasmodial and Larvicidal Effects of Surface Exudates ofGardenia ternifolia Aerial Parts. ACTA ACUST UNITED AC 2010. [DOI: 10.3923/rjpharm.2010.45.50] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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42
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Wong RPM, Lautu D, Tavul L, Hackett SL, Siba P, Karunajeewa HA, Ilett KF, Mueller I, Davis TME. In vitro sensitivity of Plasmodium falciparum to conventional and novel antimalarial drugs in Papua New Guinea. Trop Med Int Health 2010; 15:342-9. [PMID: 20070627 DOI: 10.1111/j.1365-3156.2009.02463.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Recent clinical studies have shown high rates of malaria treatment failure in endemic areas of Papua New Guinea (PNG), necessitating a change of treatment from chloroquine (CQ) or amodiaquine (AQ) plus sulphadoxine-pyrimethamine to the artemisinin combination therapy (ACT) artemether plus lumefantrine (LM). To facilitate the monitoring of antimalarial drug resistance in this setting, we assessed the in vitro sensitivity of Plasmodium falciparum isolates from Madang Province. METHODS A validated colorimetric lactate dehydrogenase assay was used to assess growth inhibition of 64 P. falciparum isolates in the presence of nine conventional or novel antimalarial drugs [CQ, AQ, monodesethyl-amodiaquine (DAQ), piperaquine (PQ), naphthoquine (NQ), mefloquine (MQ), LM, dihydroartemisinin and azithromycin (AZ)]. RESULTS The geometric mean (95% confidence interval) concentration required to inhibit parasite growth by 50% (IC(50)) was 167 (141-197) nM for CQ, and 82% of strains were resistant (threshold 100 nM), consistent with near-fixation of the CQ resistance-associated pfcrt allele in PNG. Except for AZ [8.351 (5.418-12.871) nM], the geometric mean IC(50) for the other drugs was <20 nM. There were strong associations between the IC(50)s of 4-aminoquinoline (CQ, AQ, DAQ and NQ), bisquinoline (PQ) and aryl aminoalcohol (MQ) compounds suggesting cross-resistance, but LM IC(50) only correlated with that of MQ. Conclusions Most PNG isolates are resistant to CQ in vitro but not to other ACT partner drugs. The non-isotopic semi-automated high-throughput nature of the Plasmodium lactate dehydrogenase assay facilitates the convenient serial assessment of local parasite sensitivity, so that emerging resistance can be identified with relative confidence at an early stage.
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Affiliation(s)
- Rina P M Wong
- Fremantle Unit, School of Medicine and Pharmacology, University of Western Australia, Nedlands, WA, Australia
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43
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Basak SC, Mills D, Hawkins DM, Bhattacharjee AK. Quantitative structure-activity relationship studies of antimalarial compounds from their calculated mathematical descriptors. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2010; 21:103-125. [PMID: 20373216 DOI: 10.1080/10629360903568614] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A wide range of mathematical descriptors that can be calculated without the use of any other experimental data except molecular structure were used to develop models to predict binary (+/-) antimalarial activity of a set of 86 4(1H)-quinolones in two strains of parasite: D6 and TM90-C2B (chloroquine and atovaquone susceptible). The quantitative structure-activity relationship for each strain was of high quality and showed good ability in predicting activity versus inactivity when applied to a data set containing well-known antimalarial drugs.
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Affiliation(s)
- S C Basak
- University of Minnesota Duluth, Natural Resources Research Institute, Duluth, MN, USA.
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Zhu S, Zhang Q, Gudise C, Wei L, Smith E, Zeng Y. Synthesis and biological evaluation of febrifugine analogues as potential antimalarial agents. Bioorg Med Chem 2009; 17:4496-502. [PMID: 19467876 DOI: 10.1016/j.bmc.2009.05.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 05/02/2009] [Accepted: 05/05/2009] [Indexed: 11/29/2022]
Abstract
Febrifugine is an alkaloid isolated from Dichroa febrifuga Lour as the active component against Plasmodium falciparum. Adverse side effects have precluded febrifugine as a potential clinical drug. In this study novel febrifugine analogues were designed and synthesized. Lower toxicity was achieved by reducing or eliminating the tendency of forming chemically reactive and toxic intermediates and metabolites. Synthesized compounds were evaluated for acute toxicity and in vitro and in vivo antimalarial efficacy. Some compounds are much less toxic than the natural product febrifugine and existing antimalarial drug chloroquine and are expected to possess wide therapeutic windows. These compounds, as well as the underlying design rationale, may find usefulness in the discovery and development of new antimalarial drugs.
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Affiliation(s)
- Shuren Zhu
- Radix Pharmaceuticals, Inc, Potomac, MD 20854, USA.
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45
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Colorimetric high-throughput screen for detection of heme crystallization inhibitors. Antimicrob Agents Chemother 2009; 53:2564-8. [PMID: 19307367 DOI: 10.1128/aac.01466-08] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Malaria infects 500 million people annually, a number that is likely to rise as drug resistance to currently used antimalarials increases. During its intraerythrocytic stage, the causative parasite, Plasmodium falciparum, metabolizes hemoglobin and releases toxic heme, which is neutralized by a parasite-specific crystallization mechanism to form hemozoin. Evidence suggests that chloroquine, the most successful antimalarial agent in history, acts by disrupting the formation of hemozoin. Here we describe the development of a 384-well microtiter plate screen to detect small molecules that can also disrupt heme crystallization. This assay, which is based on a colorimetric assay developed by Ncokazi and Egan (K. K. Ncokazi and T. J. Egan, Anal. Biochem. 338:306-319, 2005), requires no parasites or parasite-derived reagents and no radioactive materials and is suitable for a high-throughput screening platform. The assay's reproducibility and large dynamic range are reflected by a Z factor of 0.74. A pilot screen of 16,000 small molecules belonging to diverse structural classes was conducted. The results of the target-based assay were compared with a whole-parasite viability assay of the same small molecules to identify small molecules active in both assays.
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46
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Patel V, Booker M, Kramer M, Ross L, Celatka CA, Kennedy LM, Dvorin JD, Duraisingh MT, Sliz P, Wirth DF, Clardy J. Identification and characterization of small molecule inhibitors of Plasmodium falciparum dihydroorotate dehydrogenase. J Biol Chem 2008; 283:35078-85. [PMID: 18842591 PMCID: PMC2596402 DOI: 10.1074/jbc.m804990200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 10/06/2008] [Indexed: 11/06/2022] Open
Abstract
Plasmodium falciparum causes the most deadly form of malaria and accounts for over one million deaths annually. The malaria parasite is unable to salvage pyrimidines and relies on de novo biosynthesis for survival. Dihydroorotate dehydrogenase (DHOD), a mitochondrially localized flavoenzyme, catalyzes the rate-limiting step of this pathway and is therefore an attractive antimalarial chemotherapeutic target. Using a target-based high throughput screen, we have identified a series of potent, species-specific inhibitors of P. falciparum DHOD (pfDHOD) that are also efficacious against three cultured strains (3D7, HB3, and Dd2) of P. falciparum. The primary antimalarial mechanism of action of these compounds was confirmed to be inhibition of pfDHOD through a secondary assay with transgenic malaria parasites, and the structural basis for enzyme inhibition was explored through in silico structure-based docking and site-directed mutagenesis. Compound-mediated cytotoxicity was not observed with human dermal fibroblasts or renal epithelial cells. These data validate pfDHOD as an antimalarial drug target and provide chemical scaffolds with which to begin medicinal chemistry efforts.
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Affiliation(s)
- Vishal Patel
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Michael Booker
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Martin Kramer
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Leila Ross
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Cassandra A. Celatka
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Leah M. Kennedy
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Jeffrey D. Dvorin
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Manoj T. Duraisingh
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Piotr Sliz
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Dyann F. Wirth
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
| | - Jon Clardy
- Department of Biological
Chemistry and Molecular Pharmacology, Harvard Medical School, Boston,
Massachusetts 02115, the Department
of Immunology and Infectious Disease, Harvard School of Public Health, Boston,
Massachusetts 02115, Drug and
Biomaterial Research and Development, Genzyme Corporation, Waltham,
Massachusetts 02451, Division of
Infectious Diseases, Children's Hospital Boston, Boston, Massachusetts 02115,
and the Department of Pediatrics, Harvard
Medical School, Boston, Massachusetts 02115
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Kato N, Sakata T, Breton G, Le Roch KG, Nagle A, Andersen C, Bursulaya B, Henson K, Johnson J, Kumar KA, Marr F, Mason D, McNamara C, Plouffe D, Ramachandran V, Spooner M, Tuntland T, Zhou Y, Peters EC, Chatterjee A, Schultz PG, Ward GE, Gray N, Harper J, Winzeler EA. Gene expression signatures and small-molecule compounds link a protein kinase to Plasmodium falciparum motility. Nat Chem Biol 2008; 4:347-56. [PMID: 18454143 DOI: 10.1038/nchembio.87] [Citation(s) in RCA: 169] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2007] [Accepted: 04/04/2008] [Indexed: 01/26/2023]
Abstract
Calcium-dependent protein kinases play a crucial role in intracellular calcium signaling in plants, some algae and protozoa. In Plasmodium falciparum, calcium-dependent protein kinase 1 (PfCDPK1) is expressed during schizogony in the erythrocytic stage as well as in the sporozoite stage. It is coexpressed with genes that encode the parasite motor complex, a cellular component required for parasite invasion of host cells, parasite motility and potentially cytokinesis. A targeted gene-disruption approach demonstrated that pfcdpk1 seems to be essential for parasite viability. An in vitro biochemical screen using recombinant PfCDPK1 against a library of 20,000 compounds resulted in the identification of a series of structurally related 2,6,9-trisubstituted purines. Compound treatment caused sudden developmental arrest at the late schizont stage in P. falciparum and a large reduction in intracellular parasites in Toxoplasma gondii, which suggests a possible role for PfCDPK1 in regulation of parasite motility during egress and invasion.
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Affiliation(s)
- Nobutaka Kato
- Department of Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, ICND202 La Jolla, California 92037, USA
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Zhu S, Zhang Q, Gudise C, Meng L, Wei L, Smith E, Kong Y. Synthesis and evaluation of naphthyridine compounds as antimalarial agents. Bioorg Med Chem Lett 2007; 17:6101-6. [PMID: 17900897 PMCID: PMC2072807 DOI: 10.1016/j.bmcl.2007.09.044] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 09/09/2007] [Accepted: 09/12/2007] [Indexed: 11/28/2022]
Abstract
Primaquine is the drug of choice for the radical cure of Plasmodium vivax malaria, but possesses serious side effects. In this study novel primaquine analogues were designed and synthesized. Lower toxicity was achieved by reducing or eliminating the tendency of forming chemically reactive and toxic intermediates and metabolites. In vitro and in vivo studies found that synthesized compounds were less toxic than the parent compound primaquine, while preserving the desired antimalarial activity. Some of these compounds possess a therapeutic index over 10 times superior to that of the commonly used antimalarial drug chloroquine. These compounds, as well as the underlying design rationale, may find usefulness in the discovery and development of new antimalarial drugs.
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Affiliation(s)
- Shuren Zhu
- Radix Pharmaceuticals Inc., 880 College Parkway, Rockville, MD 20850, USA.
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Li Q, Gerena L, Xie L, Zhang J, Kyle D, Milhous W. Development and validation of flow cytometric measurement for parasitemia in cultures of P. falciparum vitally stained with YOYO-1. Cytometry A 2007; 71:297-307. [PMID: 17279569 DOI: 10.1002/cyto.a.20380] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The need for improved malaria diagnostics has long been recognized. METHODS Human parasitized erythrocytes based on the principles of flow cytometry (FCM) method is described for the determination of parasitemia in Plasmodium falciparum cultures using the fluorescence activated cell sorter and DNA-binding fluorescent dye, YOYO-1. The same assay samples can be also evaluated both microscopically and by scintillation counting after use of (3)H-hypoxanthine-labeled parasites. RESULTS The counts of uninfected, infected, and nucleated cells occurred with high precision. The cells were categorized into different populations according to their physical or chemical properties such as RNase treatment and compensation required optimization. The detection and quantitation limits in the assay were 0.003% and 0.008% parasitemia, respectively. Overall, the parasite counts by FCM measurement correlated highly (r(2) = 0.923-0.968) with the parasitemia measured by (3)H-hypoxanthine incorporation assay when parasites variants incubated with various antimalarial drugs. In addition, the low levels of parasitemia (7.9%-21.3%) detected by microscopy than by FCM may be related to a number of tiny schizonts externally attached to the erythrocyte membranes but were not definitely inside the erythrocyte that normally would never be included in microscopy counting. CONCLUSION On the basis of data reported herein, a rapid, high sensitivity, lower sampling error and reliable identification of human parasitized erythrocytes by the principles of FCM have been established. Published 2007 Wiley-Liss, Inc.
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Affiliation(s)
- Qigui Li
- Department of Pharmacology, Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, Maryland 20307-5100, USA.
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50
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Reilly HB, Wang H, Steuter JA, Marx AM, Ferdig MT. Quantitative dissection of clone-specific growth rates in cultured malaria parasites. Int J Parasitol 2007; 37:1599-607. [PMID: 17585919 PMCID: PMC2268714 DOI: 10.1016/j.ijpara.2007.05.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 05/08/2007] [Accepted: 05/10/2007] [Indexed: 11/16/2022]
Abstract
Measurement of parasite proliferation in cultured red blood cells underpins many facets of malaria research, from drug sensitivity assays to assessing the impact of experimentally altered genes on parasite growth, virulence and fitness. Pioneering efforts to grow Plasmodium falciparum in cultured red blood cells revolutionised malaria research and spurred the development of semi-high-throughput growth assays using radio-labelled hypoxanthine (Hx), an essential nucleic acid precursor, as a reporter of whole-cycle proliferation [Trager, W., Jensen, J.B., 1976. Human malaria parasites in continuous culture. Science 193, 673-675; Desjardins, R.E., Canfield, C.J., Haynes, J.D., Chulay, J.D., 1979. Quantitative assessment of antimalarial activity in vitro by a semiautomated microdilution technique. Antimicrob. Agents Chemother. 16, 710-718]. The isotopic Hx assay remains the standard quantitative growth assay with which newer non-radioactive procedures based on fluorescent DNA dyes or ELISA are compared. All of these readouts are surrogate reporters of changes in bulk parasitemias, reflecting proliferation over entire asexual reproductive cycles. While quantitatively robust and amenable to semi-high-throughput applications, these methods are blind to the underlying developmental and cellular events of growth in human red blood cells. Modern whole-genome tools including gene knockouts, mutagenesis and small molecule screens promise to reveal much about basic parasite biology; however methods to precisely quantify the within-cycle growth process are needed. Here we elaborate on the classical growth index, i.e. changes in parasitemia, by quantifying sub-phenotypes of a rapid proliferator, the multi-drug resistant clone Dd2, and a standard wild-type clone, HB3. These data illustrate differences in cycle duration, merozoite production, and invasion rate and efficiency that underpin Dd2's average 2-fold proliferation advantage over HB3 per erythrocytic cycle. The ability to refine growth phenotypes will inform the search for molecular determinants of differential parasite growth rates and broaden our understanding of killing mechanisms and cellular targets of antimalarial drugs.
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Affiliation(s)
| | | | | | | | - Michael T. Ferdig
- Corresponding author. Michael T. Ferdig, 280 Galvin Life Sciences; Notre Dame, IN 46556 USA. Tel.: +1 574 631 9973; fax: +1 574 631 0492. E-mail address:
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