1
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Kobpornchai P, Imwong M, Kulkeaw K. Trio fluorophore-based phenotypic assay for the detection of artemisinin-induced growth-arrested Plasmodium falciparum in human erythrocytes. Sci Rep 2024; 14:1802. [PMID: 38245618 PMCID: PMC10799909 DOI: 10.1038/s41598-024-52414-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 01/18/2024] [Indexed: 01/22/2024] Open
Abstract
Artemisinin combination therapy remains effective for the treatment of falciparum malaria. However, Plasmodium falciparum can escape the effects of artemisinin by arresting their growth. The growth-arrested parasites cannot be distinguished from nonviable parasites with standard microscopy techniques due to their morphological similarities. Here, we demonstrated the efficacy of a new laboratory assay that is compatible with the artemisinin susceptibility test. As a result of the differential cell permeabilities of two DNA-binding fluorophores, growth-arrested P. falciparum can be distinguished from parasites killed by artemisinin, since the latter lose cell membrane permeability. This fluorescence-based assay increased the sensitivity and specificity of the ring survival assay in the assessment of artemisinin susceptibility. When combined with a third fluorophore-conjugated anti-human leukocyte antibody, this trio fluorophore assay became more useful in identifying growth-arrested parasites in mock human blood samples. This novel assay is a simple and rapid technique for monitoring artemisinin resistance with greater sensitivity and accuracy compared with morphology-based observations under a light microscope.
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Affiliation(s)
- Porntida Kobpornchai
- Siriraj Integrative Center for Neglected Parasitic Diseases, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
- Siriraj-Long Read Lab, Department of Bioinformatics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10700, Thailand
| | - Kasem Kulkeaw
- Siriraj Integrative Center for Neglected Parasitic Diseases, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand.
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2
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Kundu M, Dutta A, Roy KK, Mal SK, Karmakar S, Mandal A, Mondal SK, Kumar S, Saha S, Pradhan S, Sarkar R, Chakrabarti M, Malik PK, Banerjee M. Identification of 5-(3-(methylsulfonyl)phenyl)-3-(4-(methylsulfonyl)phenyl)-3H-imidazo[4,5-b]pyridine as novel orally bioavailable and metabolically stable antimalarial compound for further exploration. Chem Biol Drug Des 2023; 101:690-695. [PMID: 36322010 DOI: 10.1111/cbdd.14170] [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: 04/30/2022] [Revised: 10/09/2022] [Accepted: 10/29/2022] [Indexed: 11/05/2022]
Abstract
Malaria continues to be a significant public health problem threatened by the emergence and spread of resistance to artemisinin-based combination therapies and marked half a million deaths in 2016. A new imidazopyridine chemotype has been envisaged through scaffold-hopping approach combined with docking studies for putative-binding interactions with Plasmodium falciparum phosphatidylinositol-4-kinase (PfPI4K) target. The docking results steered to the synthesis of compound 1 [5-(3-(methylsulfonyl)phenyl)-3-(4-(methylsulfonyl)phenyl)-3H-imidazo[4,5-b]pyridine] followed by the in vitro screening for antiplasmodial activity and ADME-PK studies. Combined with potent antimalarial activity of compound 1 (Pf3D7 IC50 = 29 nM) with meager in vitro intrinsic clearance, moderate plasma-protein binding, and acceptable permeability, compound 1 displayed sustained exposure and high oral bioavailability in mice and can thus have the potential as next generation PI4K inhibitor for in vivo studies.
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Affiliation(s)
| | - Aditi Dutta
- TCG Lifesciences Pvt. Ltd., Salt Lake, Kolkata, India
| | - Kuldeep K Roy
- Department of Pharmaceutical Sciences, School of Health Sciences and Technology, UPES University, Dehradun, Uttarakhand, India
| | - Sajal K Mal
- TCG Lifesciences Pvt. Ltd., Salt Lake, Kolkata, India
| | | | - Aritra Mandal
- TCG Lifesciences Pvt. Ltd., Salt Lake, Kolkata, India
| | | | - Sanjay Kumar
- TCG Lifesciences Pvt. Ltd., Salt Lake, Kolkata, India
| | - Soumya Saha
- TCG Lifesciences Pvt. Ltd., Salt Lake, Kolkata, India
| | | | - Ratul Sarkar
- TCG Lifesciences Pvt. Ltd., Salt Lake, Kolkata, India
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3
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Marreiros IM, Marques S, Parreira A, Mastrodomenico V, Mounce BC, Harris CT, Kafsack BF, Billker O, Zuzarte-Luís V, Mota MM. A non-canonical sensing pathway mediates Plasmodium adaptation to amino acid deficiency. Commun Biol 2023; 6:205. [PMID: 36810637 PMCID: PMC9942083 DOI: 10.1038/s42003-023-04566-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 02/08/2023] [Indexed: 02/23/2023] Open
Abstract
Eukaryotes have canonical pathways for responding to amino acid (AA) availability. Under AA-limiting conditions, the TOR complex is repressed, whereas the sensor kinase GCN2 is activated. While these pathways have been highly conserved throughout evolution, malaria parasites are a rare exception. Despite auxotrophic for most AA, Plasmodium does not have either a TOR complex nor the GCN2-downstream transcription factors. While Ile starvation has been shown to trigger eIF2α phosphorylation and a hibernation-like response, the overall mechanisms mediating detection and response to AA fluctuation in the absence of such pathways has remained elusive. Here we show that Plasmodium parasites rely on an efficient sensing pathway to respond to AA fluctuations. A phenotypic screen of kinase knockout mutant parasites identified nek4, eIK1 and eIK2-the last two clustering with the eukaryotic eIF2α kinases-as critical for Plasmodium to sense and respond to distinct AA-limiting conditions. Such AA-sensing pathway is temporally regulated at distinct life cycle stages, allowing parasites to actively fine-tune replication and development in response to AA availability. Collectively, our data disclose a set of heterogeneous responses to AA depletion in malaria parasites, mediated by a complex mechanism that is critical for modulating parasite growth and survival.
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Affiliation(s)
- Inês M. Marreiros
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal ,grid.5808.50000 0001 1503 7226Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Sofia Marques
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Ana Parreira
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Vincent Mastrodomenico
- grid.164971.c0000 0001 1089 6558Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA
| | - Bryan C. Mounce
- grid.164971.c0000 0001 1089 6558Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA ,grid.164971.c0000 0001 1089 6558Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA
| | - Chantal T. Harris
- grid.5386.8000000041936877XDepartment of Microbiology and Immunology, Weill Cornell Medical College, New York, NY USA ,grid.5386.8000000041936877XImmunology & Microbial Pathogenesis Graduate Program, Weill Cornell Medicine, New York, NY USA
| | - Björn F. Kafsack
- grid.5386.8000000041936877XDepartment of Microbiology and Immunology, Weill Cornell Medical College, New York, NY USA
| | - Oliver Billker
- grid.12650.300000 0001 1034 3451Molecular Infection Medicine Sweden, Molecular Biology Department, Umeå University, Umeå, S-90187 Sweden
| | - Vanessa Zuzarte-Luís
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Maria M. Mota
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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4
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Measurement of Babesia bovis infected red blood cells using flow cytometry. J Microbiol Methods 2023; 204:106641. [PMID: 36460090 DOI: 10.1016/j.mimet.2022.106641] [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: 09/07/2022] [Revised: 11/27/2022] [Accepted: 11/28/2022] [Indexed: 12/05/2022]
Abstract
Rapid and accurate tools are needed for high-throughput in vitro antibabesial drug testing. In this study, flow cytometry for the measuring of Babesia bovis in vitro culture, was developed using SYBR Green I and compared against the results of fluorescence-based assay and microscopic assay. A high correlation of measured parasitemia was observed with high R2 value (R2 = 0.9991) between flow cytometry and microscopic analysis. The degree of antibabesial drug sensitivity against B. bovis determined by flow cytometry was 0.424 ± 0.173 μM. Similar to the results of previously published studies involving fluorescence spectrometry-based assay (0.408 ± 0.011 μM) and microscopy-based assay (0.400 ± 0.017 μM). The outcomes of this present study suggest that flow cytometry assay using SYBR Green I can potentially be useful in determining parasitemia and can serve as a rapid alternative method to antibabesial drug testing.
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5
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Lam SY, Lau HL, Kwok CK. Capture-SELEX: Selection Strategy, Aptamer Identification, and Biosensing Application. BIOSENSORS 2022; 12:bios12121142. [PMID: 36551109 PMCID: PMC9776347 DOI: 10.3390/bios12121142] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 11/26/2022] [Accepted: 11/29/2022] [Indexed: 06/01/2023]
Abstract
Small-molecule contaminants, such as antibiotics, pesticides, and plasticizers, have emerged as one of the substances most detrimental to human health and the environment. Therefore, it is crucial to develop low-cost, user-friendly, and portable biosensors capable of rapidly detecting these contaminants. Antibodies have traditionally been used as biorecognition elements. However, aptamers have recently been applied as biorecognition elements in aptamer-based biosensors, also known as aptasensors. The systematic evolution of ligands by exponential enrichment (SELEX) is an in vitro technique used to generate aptamers that bind their targets with high affinity and specificity. Over the past decade, a modified SELEX method known as Capture-SELEX has been widely used to generate DNA or RNA aptamers that bind small molecules. In this review, we summarize the recent strategies used for Capture-SELEX, describe the methods commonly used for detecting and characterizing small-molecule-aptamer interactions, and discuss the development of aptamer-based biosensors for various applications. We also discuss the challenges of the Capture-SELEX platform and biosensor development and the possibilities for their future application.
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Affiliation(s)
- Sin Yu Lam
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, China
| | - Hill Lam Lau
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, China
| | - Chun Kit Kwok
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
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6
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Optimized Protocol for Microalgae DNA Staining with SYTO9/SYBR Green I, Based on Flow Cytometry and RSM Methodology: Experimental Design, Impacts and Validation. Methods Protoc 2022; 5:mps5050076. [PMID: 36287048 PMCID: PMC9612149 DOI: 10.3390/mps5050076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/17/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022] Open
Abstract
Multiple fluorochromes are extensively used to investigate different microalgal aspects, such as viability and physiology. Some of them can be used to stain nucleic acids (DNA). Well-known examples are SYBR Green I and SYTO 9, the latter of which offers several advantages, especially when combined with flow cytometry (FCM)—a powerful method for studying microalgal population heterogeneity and analyzing their cell cycles. However, the effects of these dyes on the microalgae cell physiology have not been fully elucidated yet. A statistical experimental design, using response surface methodology (RSM) with FCM was applied in this study to optimize the DNA staining of a non-conventional microalgae, Chromochloris zofingiensis, with SYBR Green I and SYTO 9, and to optimize the variables affecting staining efficiency, i.e., the dye concentration, incubation time and staining temperature. We found that none of these factors affects the staining efficiency, which was not less than 99.65%. However, for both dyes, the dye concentration was shown to be the most significant factor causing cell damage (p-values: 0.0003; <0.0001) for SYBR Green I and SYTO 9, respectively. The staining temperature was only significant for SYTO 9 (p-value: 0.0082), and no significant effect was observed regarding the incubation time for both dyes. The values of the optimized parameters (0.5 µM, 05 min and 25 °C) for SYTO 9 and (0.5 X, 5 min and 25 °C) for SYBR Green I resulted in the maximum staining efficiency (99.8%; 99.6%), and the minimum damaging effects (12.86%; 13.75%) for SYTO 9 and SYBR Green I, respectively. These results offer new perspectives for improving the use of DNA staining fluorochromes and provides insights into their possible side effects on microalgae.
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7
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Lee WC, Cheong FW, Amir A, Lai MY, Tan JH, Phang WK, Shahari S, Lau YL. Plasmodium knowlesi: the game changer for malaria eradication. Malar J 2022; 21:140. [PMID: 35505339 PMCID: PMC9066973 DOI: 10.1186/s12936-022-04131-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/18/2022] [Indexed: 11/12/2022] Open
Abstract
Plasmodium knowlesi is a zoonotic malaria parasite that has gained increasing medical interest over the past two decades. This zoonotic parasitic infection is prevalent in Southeast Asia and causes many cases with fulminant pathology. Despite several biogeographical restrictions that limit its distribution, knowlesi malaria cases have been reported in different parts of the world due to travelling and tourism activities. Here, breakthroughs and key information generated from recent (over the past five years, but not limited to) studies conducted on P. knowlesi were reviewed, and the knowledge gap in various research aspects that need to be filled was discussed. Besides, challenges and strategies required to control and eradicate human malaria with this emerging and potentially fatal zoonosis were described.
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Affiliation(s)
- Wenn-Chyau Lee
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Fei Wen Cheong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Amirah Amir
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Meng Yee Lai
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jia Hui Tan
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wei Kit Phang
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Shahhaziq Shahari
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
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8
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Hviid L, Lopez-Perez M. Analysis by Flow Cytometry of α 2-Macroglobulin and Nonimmune IgM-Binding to Plasmodium falciparum-Infected Erythrocytes. Methods Mol Biol 2022; 2470:435-444. [PMID: 35881364 DOI: 10.1007/978-1-0716-2189-9_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Several members of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family can bind human serum proteins such as IgM and α2-macroglobulin (α2M). This binding seems to play a role in pathogenesis and immune evasion by improving the avidity of PfEMP1-mediated binding to erythrocyte receptors and/or by masking antibody epitopes in PfEMP1. In this protocol, we describe a flow cytometry-based protocol to evaluate IgM- and α2M-binding to intact and unfixed mature-stage IEs. The method can be used for laboratory clones and field isolates.
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Affiliation(s)
- Lars Hviid
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Centre for Medical Parasitology, Rigshospitalet, Copenhagen, Denmark
| | - Mary Lopez-Perez
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark.
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9
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Lopez-Perez M, Olsen RW. Immunomagnetic Selection of Plasmodium falciparum-Infected Erythrocytes Expressing Particular PfEMP1 Variants. Methods Mol Biol 2022; 2470:69-78. [PMID: 35881339 DOI: 10.1007/978-1-0716-2189-9_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Plasmodium falciparum expresses a broad range of proteins on the surface of infected erythrocytes (IEs), including members of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family. This protocol describes an immunomagnetic selection method using PfEMP1-specific antibodies to obtain a parasite clone homogenously expressing a particular PfEMP1 protein. The expression of the corresponding PfEMP1 is later tested by flow cytometry, and the selected parasites can be used for further analysis.
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Affiliation(s)
- Mary Lopez-Perez
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Rebecca Wendelboe Olsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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10
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Macedo-Silva T, Desai SA, Wunderlich G. Improved Plasmodium falciparum dilution cloning through efficient quantification of parasite numbers and c-SNARF detection. Malar J 2021; 20:279. [PMID: 34162381 PMCID: PMC8220766 DOI: 10.1186/s12936-021-03816-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/12/2021] [Indexed: 11/24/2022] Open
Abstract
Background Molecular and genetic studies of blood-stage Plasmodium falciparum parasites require limiting dilution cloning and prolonged cultivation in microplates. The entire process is laborious and subject to errors due to inaccurate dilutions at the onset and failed detection of parasite growth in individual microplate wells. Methods To precisely control the number of parasites dispensed into each microplate well, parasitaemia and total cell counts were determined by flow cytometry using parasite cultures stained with ethidium bromide or SYBR Green I. Microplates were seeded with 0.2 or 0.3 infected cells/well and cultivated with fresh erythrocytes. The c-SNARF fluorescent pH indicator was then used to reliably detect parasite growth. Results Flow cytometry required less time than the traditional approach of estimating parasitaemia and cell numbers by microscopic examination. The resulting dilutions matched predictions from Poisson distribution calculations and yielded clonal lines. Addition of c-SNARF to media permitted rapid detection of parasite growth in microplate wells with high confidence. Conclusion The combined use of flow cytometry for precise dilution and the c-SNARF method for detection of growth improves limiting dilution cloning of P. falciparum. This simple approach saves time, is scalable, and maximizes identification of desired parasite clones. It will facilitate DNA transfection studies and isolation of parasite clones from ex vivo blood samples.
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Affiliation(s)
- Tatiane Macedo-Silva
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil.,The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Sanjay A Desai
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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11
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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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12
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Dos Santos LI, Torres TA, Diniz SQ, Gonçalves R, Caballero-Flores G, Núñez G, Gazzinelli RT, Maloy KJ, Ribeiro do V Antonelli L. Disrupted Iron Metabolism and Mortality during Co-infection with Malaria and an Intestinal Gram-Negative Extracellular Pathogen. Cell Rep 2021; 34:108613. [PMID: 33440153 PMCID: PMC8655499 DOI: 10.1016/j.celrep.2020.108613] [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: 02/17/2020] [Revised: 10/31/2020] [Accepted: 12/16/2020] [Indexed: 11/29/2022] Open
Abstract
Individuals with malaria exhibit increased morbidity and mortality when infected with Gram-negative (Gr−) bacteria. To explore this experimentally, we performed co-infection of mice with Plasmodium chabaudi and Citrobacter rodentium, an extracellular Gr− bacterial pathogen that infects the large intestine. While single infections are controlled effectively, co-infection results in enhanced virulence that is characterized by prolonged systemic bacterial persistence and high mortality. Mortality in co-infected mice is associated with disrupted iron metabolism, elevated levels of plasma heme, and increased mitochondrial reactive oxygen species (ROS) production by phagocytes. In addition, iron acquisition by the bacterium plays a key role in pathogenesis because co-infection with a mutant C. rodentium strain lacking a critical iron acquisition pathway does not cause mortality. These results indicate that disrupted iron metabolism may drive mortality during co-infection with C. rodentium and P. chabaudi by both altering host immune responses and facilitating bacterial persistence. Co-infection with malaria and a Gram-negative bacterial pathogen leads to high mortality Co-infection leads to elevated plasma heme and systemic bacterial persistence Iron acquisition is critical for bacterial persistence and mortality
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Affiliation(s)
- Luara Isabela Dos Santos
- Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte 30190-009, Minas Gerais, Brazil; Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Thais Abdala Torres
- Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte 30190-009, Minas Gerais, Brazil; Instituto de Ciências Biológicas, Departamento de Bioquimica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil
| | - Suelen Queiroz Diniz
- Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte 30190-009, Minas Gerais, Brazil; Instituto de Ciências Biológicas, Departamento de Bioquimica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil
| | - Ricardo Gonçalves
- Departamento de Patologia Geral, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Minhas Gerais, Brazil
| | - Gustavo Caballero-Flores
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Gabriel Núñez
- Department of Pathology and Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Ricardo Tostes Gazzinelli
- Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte 30190-009, Minas Gerais, Brazil; Instituto de Ciências Biológicas, Departamento de Bioquimica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil; University of Massachusetts Medical School, Worcester, MA 01605-2324, USA
| | - Kevin Joseph Maloy
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK; Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, Scotland.
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13
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Lysercell M enhances the detection of stage-specific Plasmodium-infected red blood cells in the automated hematology analyzer XN-31 prototype. Parasitol Int 2020; 80:102206. [PMID: 33049417 DOI: 10.1016/j.parint.2020.102206] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/27/2020] [Accepted: 06/28/2020] [Indexed: 11/22/2022]
Abstract
The automated hematology analyzers XN-30 (for research) and XN-31 prototype (for diagnosis support) can easily and rapidly detect Plasmodium-infected red blood cells (iRBCs) and distinguish the developmental stages of the parasite in approximately 1 min. Two dedicated reagents, Lysercell M and Fluorocell M, are available with the analyzers. Lysercell M plays an indispensable role in enhancing the fluorescence intensity of the nucleic acid staining dye in Fluorocell M and altering cell morphology. These effects of Lysercell M have been empirically determined but insufficiently analyzed. In this study, the properties of Lysercell M were analyzed using two flow cytometers and a fluorescence microscope. First, the fluorescence intensity emitted by iRBCs treated with Lysercell M or phosphate-buffered saline (PBS) was evaluated. Second, the size of RBCs treated with Lysercell M or PBS was measured. Finally, the morphology of individual parasites was observed after reconstruction of an M scattergram, a cytogram of the XN-31 prototype system, using an imaging flow cytometer. These analyses showed that treatment of iRBCs with Lysercell M increased the fluorescence intensity of stained parasite nucleic acids by approximately 10-fold and reduced the size of iRBCs in a stage-specific manner, facilitating the identification and quantification of ring form, trophozoite, and schizont stage iRBCs. These properties suggest that Lysercell M is useful for rapidly detecting iRBCs and accurately distinguishing the parasite developmental stages, thereby contributing to the usability of the XN-30 and XN-31 prototype analyzers.
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Mohring F, Rawlinson TA, Draper SJ, Moon RW. Multiplication and Growth Inhibition Activity Assays for the Zoonotic Malaria Parasite, Plasmodium knowlesi. Bio Protoc 2020; 10:e3743. [PMID: 33659403 DOI: 10.21769/bioprotoc.3743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 06/15/2020] [Accepted: 07/15/2020] [Indexed: 01/19/2023] Open
Abstract
Malaria remains a major cause of morbidity and mortality globally. Clinical symptoms of the disease arise from the growth and multiplication of Plasmodium parasites within the blood of the host. Thus in vitro assays to determine how drug, antibody and genetic perturbations affect the growth rate of Plasmodium parasites are essential for the development of new therapeutics and improving our understanding of parasite biology. As both P. falciparum and P. knowlesi can be maintained in culture with human red blood cells, the effect of antimalarial drugs and inhibitory antibodies that target the invasion capacity of Plasmodium parasites are routinely investigated by using multiplication assays or growth inhibition assays against these two species. This protocol gives detailed step-by-step procedures to carry out flow cytometry-based multiplication assays and growth inhibition activity assays to test neutralizing antibodies based on the activity of the parasite enzyme lactate dehydrogenase of Plasmodium knowlesi adapted to human red blood cell culture. Whilst similar assays are well established for P. falciparum, P. knowlesi is more closely related to all other human infective species ( Pacheco et al., 2018 ) and so can be used as a surrogate for testing drugs and vaccines for other malaria species such as P. vivax, which is the most widespread cause of malaria outside of Africa, but cannot yet be cultured under laboratory conditions.
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Affiliation(s)
- Franziska Mohring
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Thomas A Rawlinson
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Simon J Draper
- The Jenner Institute, University of Oxford, Oxford, OX3 7DQ, United Kingdom
| | - Robert W Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
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15
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A modified two-color flow cytometry assay to quantify in-vitro reinvasion and determine invasion phenotypes at low Plasmodium falciparum parasitemia. Exp Parasitol 2020; 218:107969. [PMID: 32858043 DOI: 10.1016/j.exppara.2020.107969] [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: 02/14/2020] [Revised: 07/31/2020] [Accepted: 08/05/2020] [Indexed: 11/22/2022]
Abstract
Invasion of human red blood cells (RBCs) by Plasmodium parasites is a crucial yet poorly characterised phenotype. Two-color flow cytometry (2cFCM) promises to be a very sensitive and high throughput method for phenotyping parasite invasion. However, current protocols require high (~1.0%) parasitemia for assay set-up and need to be adapted for low parasitemia samples, which are becoming increasingly common in low transmission settings. Background fluorescence from nuclei-containing uninfected RBCs and high autologous reinvasion rates (merozoite invasion of donor uninfected RBCs present at 50% assay volume) are some of the limitations to the method's sensitivity to enumerate low parasitemia (<0.5%) with nucleic acid-based stains. Here, we describe modifications for plating unlabeled donor to labeled target RBCs per assay well and for gating parasitemia, that produces accurate quantifications of low reinvasion parasitemia. Plasmodium falciparum 3D7, Dd2 and field isolates at various low and high parasitemia (0.05%-2.0%) were used to set-up SyBr Green 1-based 2cFCM invasion assays. Target RBCs were labeled with CTFR proliferation dye. We show that this dye combination allowed for efficient parasite invasion into target RBCs and that a 1:3 ratio of unlabeled to labeled RBCs per assay greatly skewed autologous reinvasion (p < 0.001). Accuracy of quantifying reinvasion was limited to an assay parasitemia of 0.02% with minimal background interference. Invasion inhibition by enzymatic treatments increased averagely by 10% (p<0.05) across the entire parasitemia range. The effect was greater for samples with <0.5% parasitemia. Overall, a more sensitive method for phenotyping invasion of low P. falciparum parasitemia is described.
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Hayakawa EH, Kato H, Nardone GA, Usukura J. A prospective mechanism and source of cholesterol uptake by Plasmodium falciparum-infected erythrocytes co-cultured with HepG2 cells. Parasitol Int 2020; 80:102179. [PMID: 32853776 DOI: 10.1016/j.parint.2020.102179] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 06/23/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022]
Abstract
Plasmodium falciparum (P. falciparum) parasites still cause lethal infections worldwide, especially in Africa (https://www.who.int/publications/i/item/world-malaria-report-2019). During P. falciparum blood-stage infections in humans, low-density lipoprotein, high-density lipoprotein and cholesterol levels in the blood become low. Because P. falciparum lacks a de novo cholesterol synthesis pathway, it must import cholesterol from the surrounding environment. However, the origin of the cholesterol and how it is taken up by the parasite across the multiple membranes that surround it is not fully understood. To answer this, we used a cholesterol synthesis inhibiter (simvastatin), a cholesterol transport inhibitor (ezetimibe), and an activating ligand of the peroxisome proliferator-activated receptor α, called ciprofibrate, to investigate the effects of these agents on the intraerythrocytic growth of P. falciparum, both with and without HepG2 cells as the lipoprotein feeders. P. falciparum growth was inhibited in the presence of ezetimibe, but ezetimibe was not very effective at inhibiting P. falciparum growth when used in the co-culture system, unlike simvastatin, which strongly promoted parasite growth in this system. Ezetimibe is known to inhibit cholesterol absorption by blocking the activity of Niemann-Pick C1 like 1 (NPC1L1) protein, and simvastatin is known to enhance NPC1L1 expression in the human body's small intestine. Collectively, our results support the possibility that cholesterol import by P. falciparum involves hepatocytes, and cholesterol uptake into the parasite occurs via NPC1L1 protein or an NPC1L1 homolog during the erythrocytic stages of the P. falciparum lifecycle.
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Affiliation(s)
- Eri H Hayakawa
- Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke, Tochigi 329-0498, Japan.
| | - Hirotomo Kato
- Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke, Tochigi 329-0498, Japan
| | - Glenn A Nardone
- Research Technology Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-5766, USA
| | - Jiro Usukura
- Institute of Material and Systems for Sustainability, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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17
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A Comparison Between Manual Count, Flow Cytometry and Quantitative Real-Time Polymerase Chain Reaction as a Means of Determining Babesia rossi Parasitaemia in Naturally Infected Dogs. Acta Parasitol 2020; 65:128-135. [PMID: 31721056 DOI: 10.2478/s11686-019-00134-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 10/03/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE Light microscopic manual count is the current gold standard for parasite quantification. The ability to determine parasite density in whole blood is crucial to understanding disease pathogenesis and finding a suitable automated method of Babesia rossi parasite quantification would facilitate higher throughput and provide results that are more objective. This study investigated both peripheral capillary and central venous whole blood to estimate the correlations between light microscopy, flow cytometry and quantitative real-time polymerase chain reaction (qPCR). METHODS Peripheral capillary and central venous blood were sampled from 40 naturally B. rossi-infected dogs and 10 healthy control dogs. Samples were analysed by reverse line blot hybridization assay to confirm a mono-B. rossi infection. Capillary blood parasite density was detected using light microscopic manual counting and venous blood parasitaemia detected by manual counts, flow cytometry and qPCR. RESULTS A significant correlation was found between the venous manual counts and flow cytometry (rs = 0.465; P < 0.001), as well as qPCR (rs = - 0.500; P < 0.001). A significant correlation was also observed between the capillary manual counts compared to venous manual counts (rs = 0.793; P < 0.001), flow cytometry (rs = 0.399; P = 0.004), and qPCR (rs = - 0.526; P < 0.001). CONCLUSIONS The study results suggest that qPCR is of value as an alternative to the gold standard manual count for detecting B. rossi parasitaemia in canine whole blood and that flow cytometry may be useful with further refinement of issues such as background fluorescence and the influence of reticulocytes.
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18
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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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19
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Real-time cholesterol sorting in Plasmodium falciparum-erythrocytes as revealed by 3D label-free imaging. Sci Rep 2020; 10:2794. [PMID: 32066816 PMCID: PMC7026401 DOI: 10.1038/s41598-020-59552-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 01/28/2020] [Indexed: 12/18/2022] Open
Abstract
Cholesterol, a necessary component of animal cell membranes, is also needed by the lethal human malaria parasite Plasmodium falciparum. Because P. falciparum lacks a cholesterol synthesis pathway and malaria patients have low blood cholesterol, we speculated that it scavenges cholesterol from them in some way. We used time-lapse holotomographic microscopy to observe cholesterol transport in live P. falciparum parasites and structurally investigate erythrocyte membranes, both during and after P. falciparum invasion of human erythrocytes. After P. falciparum initially acquired free cholesterol or inner erythrocytic membrane-derived cholesterol, we observed budding lipid membranes elongating into the cytosol and/or membrane segments migrating there and eventually fusing with the parasite membranes, presumably at the parasitophorous vacuole membrane (PVM). Finally, the cholesterol-containing segments were seen to surround the parasite nucleus. Our imaging data suggest that a novel membrane transport system operates in the cytosol of P. falciparum-infected erythrocytes as a cholesterol import system, likely between the PVM and the erythrocyte membrane, and that this transportation process occurs during the live erythrocyte stages of P. falciparum.
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20
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Linzke M, Yan SLR, Tárnok A, Ulrich H, Groves MR, Wrenger C. Live and Let Dye: Visualizing the Cellular Compartments of the Malaria Parasite Plasmodium falciparum. Cytometry A 2019; 97:694-705. [PMID: 31738009 DOI: 10.1002/cyto.a.23927] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 10/03/2019] [Accepted: 10/24/2019] [Indexed: 12/15/2022]
Abstract
Malaria remains one of the deadliest diseases worldwide and it is caused by the protozoan parasite Plasmodium spp. Parasite visualization is an important tool for the correct detection of malarial cases but also to understand its biology. Advances in visualization techniques promote new insights into the complex life cycle and biology of Plasmodium parasites. Live cell imaging by fluorescence microscopy or flow cytometry are the foundation of the visualization technique for malaria research. In this review, we present an overview of possibilities in live cell imaging of the malaria parasite. We discuss some of the state-of-the-art techniques to visualize organelles and processes of the parasite and discuss limitation and advantages of each technique. © 2019 International Society for Advancement of Cytometry.
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Affiliation(s)
- Marleen Linzke
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
| | - Sun Liu Rei Yan
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
| | - Attila Tárnok
- Institute for Medical Informatics, Statistics and Epidemiology, Medical Faculty, University Leipzig, D-04107, Härtelstraße 16-18, Leipzig, Germany
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, São Paulo, São Paulo, 05508-900, Brazil
| | - Matthew R Groves
- Structural Biology Unit, Department of Pharmacy, Faculty of Science and Engineering, University of Groningen, 9713AV, Antonius Deusinglaan 1, AV Groningen, The Netherlands
| | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
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21
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Aguiar AC, de Sousa LR, Garcia CR, Oliva G, Guido RV. New Molecular Targets and Strategies for Antimalarial Discovery. Curr Med Chem 2019; 26:4380-4402. [DOI: 10.2174/0929867324666170830103003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/24/2017] [Accepted: 07/24/2017] [Indexed: 02/07/2023]
Abstract
Malaria remains a major health problem, especially because of the emergence
of resistant P. falciparum strains to artemisinin derivatives. In this context, safe and affordable
antimalarial drugs are desperately needed. New proteins have been investigated
as molecular targets for research and development of innovative compounds with welldefined
mechanism of action. In this review, we highlight genetically and clinically validated
plasmodial proteins as drug targets for the next generation of therapeutics. The enzymes
described herein are involved in hemoglobin hydrolysis, the invasion process,
elongation factors for protein synthesis, pyrimidine biosynthesis, post-translational modifications
such as prenylation, phosphorylation and histone acetylation, generation of ATP
in mitochondrial metabolism and aminoacylation of RNAs. Significant advances on proteomics,
genetics, structural biology, computational and biophysical methods provided
invaluable molecular and structural information about these drug targets. Based on this,
several strategies and models have been applied to identify and improve lead compounds.
This review presents the recent progresses in the discovery of antimalarial drug candidates,
highlighting the approaches, challenges, and perspectives to deliver affordable, safe
and low single-dose medicines to treat malaria.
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Affiliation(s)
- Anna Caroline Aguiar
- Sao Carlos Institute of Physics, University of Sao Paulo, PO Box 369, 13560-970, Sao Carlos, SP, Brazil
| | - Lorena R.F. de Sousa
- Sao Carlos Institute of Physics, University of Sao Paulo, PO Box 369, 13560-970, Sao Carlos, SP, Brazil
| | - Celia R.S. Garcia
- Physiology Department, Bioscience Institute, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Glaucius Oliva
- Sao Carlos Institute of Physics, University of Sao Paulo, PO Box 369, 13560-970, Sao Carlos, SP, Brazil
| | - Rafael V.C. Guido
- Sao Carlos Institute of Physics, University of Sao Paulo, PO Box 369, 13560-970, Sao Carlos, SP, Brazil
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22
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Tonk M, Pierrot C, Cabezas-Cruz A, Rahnamaeian M, Khalife J, Vilcinskas A. The Drosophila melanogaster antimicrobial peptides Mtk-1 and Mtk-2 are active against the malarial parasite Plasmodium falciparum. Parasitol Res 2019; 118:1993-1998. [PMID: 31001677 DOI: 10.1007/s00436-019-06305-x] [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: 12/13/2018] [Accepted: 03/26/2019] [Indexed: 12/14/2022]
Abstract
Antimicrobial peptides (AMPs) are important components of the vertebrate and invertebrate innate immune systems. Although AMPs are widely recognized for their broad-spectrum activity against bacteria, fungi, and viruses, their activity against protozoan parasites has not been investigated in detail. In this study, we tested 10 AMPs from three different insect species: the greater wax moth Galleria mellonella (cecropin A-D), the fruit fly Drosophila melanogaster (drosocin, Mtk-1 and Mtk-2), and the blow fly Lucilia sericata (LSerPRP-2, LSerPRP-3 and stomoxyn). We tested each AMP against the protozoan parasite Plasmodium falciparum which is responsible for the most severe form of malaria in humans. We also evaluated the impact of these insect AMPs on mouse and pig erythrocytes. Whereas all AMPs showed low hemolytic effects towards mouse and pig erythrocytes, only D. melanogaster Mtk-1 and Mtk-2 significantly inhibited the growth of P. falciparum at low concentrations. Mtk-1 and Mtk-2 could therefore be considered as leads for the development of antiparasitic drugs targeting the clinically important asexual blood stage of P. falciparum.
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Affiliation(s)
- Miray Tonk
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberganlage 25, 60325, Frankfurt, Germany. .,Institute for Insect Biotechnology, Justus Liebig University of Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany. .,LOEWE Centre for Insect Biotechnology and Bioresources, Winchester Str. 2, 35392, Giessen, Germany.
| | - Christine Pierrot
- Center for Infection and Immunity of Lille (CIIL), INSERM U1019 - CNRS UMR 8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France
| | - Alejandro Cabezas-Cruz
- UMR BIPAR, INRA, ANSES, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, 94700, Maisons-Alfort, France
| | - Mohammad Rahnamaeian
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, 35394, Giessen, Germany
| | - Jamal Khalife
- Center for Infection and Immunity of Lille (CIIL), INSERM U1019 - CNRS UMR 8204, Institut Pasteur de Lille, Université Lille Nord de France, Lille, France
| | - Andreas Vilcinskas
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberganlage 25, 60325, Frankfurt, Germany.,Institute for Insect Biotechnology, Justus Liebig University of Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.,LOEWE Centre for Insect Biotechnology and Bioresources, Winchester Str. 2, 35392, Giessen, Germany.,Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, 35394, Giessen, Germany
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Vimonpatranon S, Chotivanich K, Sukapirom K, Lertjuthaporn S, Khowawisetsut L, Pattanapanyasat K. Enumeration of the Invasion Efficiency of Plasmodium falciparum In Vitro in Four Different Red Blood Cell Populations Using a Three-Color Flow Cytometry-Based Method. Cytometry A 2019; 95:737-745. [PMID: 30924603 DOI: 10.1002/cyto.a.23750] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/28/2019] [Accepted: 03/08/2019] [Indexed: 12/18/2022]
Abstract
A novel in vitro culture system using variable concentrations of biotin/streptavidin to label red blood cells (RBCs) that allows for the simultaneous comparison of growth rates in Plasmodium falciparum malaria parasite in four heterogeneous target RBC populations is described. Donor RBCs containing both P. falciparum-infected RBCs and non-infected RBCs at 0.5% parasitemia were first labeled with 7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one) succinimidyl ester (DDAO-SE) followed by co-culture with a mixture of equal numbers of four differentially biotin/streptavidin labeled RBC populations. After two to three schizogonic growth cycles, co-cultures were harvested and stained with streptavidin-phycoerythrin (SA-PE) followed by staining of parasite-infected RBCs with nucleic acid fluorochrome SYBR Green I. To demonstrate the application of this method, some target RBC populations that had sialic acid residues removed using neuraminidase treatment were mixed with RBC populations without enzymatic treatment and incubated with donor parasitized RBCs strain W2 (sialic acid-dependent) or 3D7 (sialic acid-independent). Significant less susceptibility to malaria parasite invasion was obtained with enzyme-treated RBC populations when compared with non-treated RBCs in blood samples from the same individual when using malaria parasite strain W2, whereas no difference in percent parasitemias was noted following infection with malaria parasite strain 3D7. This novel malaria culture method is cheap and provides increased sensitivity for direct comparison of parasite growth over time of any of the four RBC populations under identical conditions and eliminates the experimental bias due to contaminated donor RBCs. The application of biotin-labeled RBCs will therefore provide a better understanding of invasion phenotype-specific host-parasite interactions and the extent of complex malaria invasion mechanism. © 2019 International Society for Advancement of Cytometry.
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Affiliation(s)
- Sinmanus Vimonpatranon
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Center of Excellence for Microparticle and Exosome in Diseases, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kesinee Chotivanich
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kasama Sukapirom
- Center of Excellence for Microparticle and Exosome in Diseases, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Sakaorat Lertjuthaporn
- Center of Excellence for Microparticle and Exosome in Diseases, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Ladawan Khowawisetsut
- Center of Excellence for Microparticle and Exosome in Diseases, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kovit Pattanapanyasat
- Center of Excellence for Microparticle and Exosome in Diseases, Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Fitness Loss under Amino Acid Starvation in Artemisinin-Resistant Plasmodium falciparum Isolates from Cambodia. Sci Rep 2018; 8:12622. [PMID: 30135481 PMCID: PMC6105667 DOI: 10.1038/s41598-018-30593-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/31/2018] [Indexed: 11/09/2022] Open
Abstract
Artemisinin is the most rapidly effective drug for Plasmodium falciparum malaria treatment currently in clinical use. Emerging artemisinin-resistant parasites pose a great global health risk. At present, the level of artemisinin resistance is still relatively low with evidence pointing towards a trade-off between artemisinin resistance and fitness loss. Here we show that artemisinin-resistant P. falciparum isolates from Cambodia manifested fitness loss, showing fewer progenies during the intra-erythrocytic developmental cycle. The loss in fitness was exacerbated under the condition of low exogenous amino acid supply. The resistant parasites failed to undergo maturation, whereas their drug-sensitive counterparts were able to complete the erythrocytic cycle under conditions of amino acid deprivation. The artemisinin-resistant phenotype was not stable, and loss of the phenotype was associated with changes in the expression of a putative target, Exp1, a membrane glutathione transferase. Analysis of SNPs in haemoglobin processing genes revealed associations with parasite clearance times, suggesting changes in haemoglobin catabolism may contribute to artemisinin resistance. These findings on fitness and protein homeostasis could provide clues on how to contain emerging artemisinin-resistant parasites.
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25
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Muh F, Lee SK, Hoque MR, Han JH, Park JH, Firdaus ER, Moon RW, Lau YL, Han ET. In vitro invasion inhibition assay using antibodies against Plasmodium knowlesi Duffy binding protein alpha and apical membrane antigen protein 1 in human erythrocyte-adapted P. knowlesi A1-H.1 strain. Malar J 2018; 17:272. [PMID: 30049277 PMCID: PMC6062950 DOI: 10.1186/s12936-018-2420-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/18/2018] [Indexed: 12/22/2022] Open
Abstract
Background The rapid process of malaria erythrocyte invasion involves ligand–receptor interactions. Inducing antibodies against specific ligands or receptors that abrogate the
invasion process is a key challenge for blood stage vaccine development. However, few candidates were reported and remain to be validated for the discovery of new vaccine candidates in Plasmodium knowlesi. Methods In order to investigate the efficacy of pre-clinical vaccine candidates in P. knowlesi-infected human cases, this study describes an in vitro invasion inhibition assay, using a P. knowlesi strain adapted to in vitro growth in human erythrocytes, PkA1-H.1. Recombinant proteins of P. knowlesi Duffy binding protein alpha (PkDBPα) and apical membrane antigen 1 (PkAMA1) were produced in Escherichia coli system and rabbit antibodies were generated from immune animals. Results PkDBPα and PkAMA1 recombinant proteins were expressed as insoluble and produced as a functional refolded form for this study. Antibodies against PkDBPα and PkAMA1 specifically recognized recombinant proteins and native parasite proteins in schizont-stage parasites on the merozoite organelles. Single and combination of anti-PkDBPα and anti-PkAMA1 antibodies elicited strong growth inhibitory effects on the parasite in concentration-dependent manner. Meanwhile, IgG prevalence of PkDBPα and PkAMA1 were observed in 13.0 and 46.7% in human clinical patients, respectively. Conclusion These data provide support for the validation of in vitro growth inhibition assay using antibodies of DBPα and AMA1 in human-adapted P. knowlesi parasite PkA1-H.1 strain. Electronic supplementary material The online version of this article (10.1186/s12936-018-2420-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fauzi Muh
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Seong-Kyun Lee
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Mohammad Rafiul Hoque
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Ji-Hoon Park
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Egy Rahman Firdaus
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Robert W Moon
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, 24341, Republic of Korea.
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Synthesis, biological characterisation and structure activity relationships of aromatic bisamidines active against Plasmodium falciparum. Eur J Med Chem 2017; 127:22-40. [DOI: 10.1016/j.ejmech.2016.12.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 01/27/2023]
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Kesely KR, Pantaleo A, Turrini FM, Olupot-Olupot P, Low PS. Inhibition of an Erythrocyte Tyrosine Kinase with Imatinib Prevents Plasmodium falciparum Egress and Terminates Parasitemia. PLoS One 2016; 11:e0164895. [PMID: 27768734 PMCID: PMC5074466 DOI: 10.1371/journal.pone.0164895] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 10/03/2016] [Indexed: 11/18/2022] Open
Abstract
With half of the world's population at risk for malaria infection and with drug resistance on the rise, the search for mutation-resistant therapies has intensified. We report here a therapy for Plasmodium falciparum malaria that acts by inhibiting the phosphorylation of erythrocyte membrane band 3 by an erythrocyte tyrosine kinase. Because tyrosine phosphorylation of band 3 causes a destabilization of the erythrocyte membrane required for parasite egress, inhibition of the erythrocyte tyrosine kinase leads to parasite entrapment and termination of the infection. Moreover, because one of the kinase inhibitors to demonstrate antimalarial activity is imatinib, i.e. an FDA-approved drug authorized for use in children, translation of the therapy into the clinic will be facilitated. At a time when drug resistant strains of P. falciparum are emerging, a strategy that targets a host enzyme that cannot be mutated by the parasite should constitute a therapeutic mechanism that will retard evolution of resistance.
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Affiliation(s)
- Kristina R. Kesely
- Purdue Institute for Drug Discovery, Purdue University, West Lafayette, 47907, United States of America
- Purdue Department of Chemistry, Purdue University, West Lafayette, 47907, United States of America
| | - Antonella Pantaleo
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Francesco M. Turrini
- Department of Genetics, Biology and Biochemistry, University of Turin, Turin, Italy
| | - Peter Olupot-Olupot
- Department of Paediatrics/Research Unit, Mbale Regional Referral Hospital, Mbale, Uganda
| | - Philip S. Low
- Purdue Institute for Drug Discovery, Purdue University, West Lafayette, 47907, United States of America
- Purdue Department of Chemistry, Purdue University, West Lafayette, 47907, United States of America
- * E-mail:
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Cabezas-Cruz A, Tonk M, Bouchut A, Pierrot C, Pierce RJ, Kotsyfakis M, Rahnamaeian M, Vilcinskas A, Khalife J, Valdés JJ. Antiplasmodial Activity Is an Ancient and Conserved Feature of Tick Defensins. Front Microbiol 2016; 7:1682. [PMID: 27822206 PMCID: PMC5075766 DOI: 10.3389/fmicb.2016.01682] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 10/07/2016] [Indexed: 01/20/2023] Open
Abstract
Ancestral sequence reconstruction has been widely used to test evolution-based hypotheses. The genome of the European tick vector, Ixodes ricinus, encodes for defensin peptides with diverse antimicrobial activities against distantly related pathogens. These pathogens include fungi, Gram-negative, and Gram-positive bacteria, i.e., a wide antimicrobial spectrum. Ticks do not transmit these pathogens, suggesting that these defensins may act against a wide range of microbes encountered by ticks during blood feeding or off-host periods. As demonstrated here, these I. ricinus defensins are also effective against the apicomplexan parasite Plasmodium falciparum. To study the general evolution of antimicrobial activity in tick defensins, the ancestral amino acid sequence of chelicerate defensins, which existed approximately 444 million years ago, was reconstructed using publicly available scorpion and tick defensin sequences (named Scorpions-Ticks Defensins Ancestor, STiDA). The activity of STiDA was tested against P. falciparum and the same Gram-negative and Gram-positive bacteria that were used for the I. ricinus defensins. While some extant tick defensins exhibit a wide antimicrobial spectrum, the ancestral defensin showed moderate activity against one of the tested microbes, P. falciparum. This study suggests that amino acid variability and defensin family expansion increased the antimicrobial spectrum of ancestral tick defensins.
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Affiliation(s)
- Alejandro Cabezas-Cruz
- Institute of Parasitology, Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – Centre d’Infection et d’Immunité de LilleLille, France
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences (ACVR)České Budějovice, Czech Republic
- Faculty of Science, University of South BohemiaČeské Budějovice, Czech Republic
| | - Miray Tonk
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied EcologyGiessen, Germany
| | - Anne Bouchut
- Institute of Parasitology, Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – Centre d’Infection et d’Immunité de LilleLille, France
| | - Christine Pierrot
- Institute of Parasitology, Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – Centre d’Infection et d’Immunité de LilleLille, France
| | - Raymond J. Pierce
- Institute of Parasitology, Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – Centre d’Infection et d’Immunité de LilleLille, France
| | - Michalis Kotsyfakis
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences (ACVR)České Budějovice, Czech Republic
| | - Mohammad Rahnamaeian
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied EcologyGiessen, Germany
- Institute for Insect Biotechnology, Justus-Liebig-University of GiessenGiessen, Germany
| | - Andreas Vilcinskas
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied EcologyGiessen, Germany
- Institute for Insect Biotechnology, Justus-Liebig-University of GiessenGiessen, Germany
| | - Jamal Khalife
- Institute of Parasitology, Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – Centre d’Infection et d’Immunité de LilleLille, France
- *Correspondence: James J. Valdés, Jamal Khalife,
| | - James J. Valdés
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences (ACVR)České Budějovice, Czech Republic
- Department of Virology, Veterinary Research InstituteBrno, Czech Republic
- *Correspondence: James J. Valdés, Jamal Khalife,
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Wirjanata G, Handayuni I, Prayoga P, Apriyanti D, Chalfein F, Sebayang BF, Kho S, Noviyanti R, Kenangalem E, Campo B, Poespoprodjo JR, Price RN, Marfurt J. Quantification of Plasmodium ex vivo drug susceptibility by flow cytometry. Malar J 2015; 14:417. [PMID: 26498665 PMCID: PMC4619360 DOI: 10.1186/s12936-015-0940-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The emergence and spread of multidrug-resistant Plasmodium falciparum and Plasmodium vivax highlights the need for objective measures of ex vivo drug susceptibility. Flow cytometry (FC) has potential to provide a robust and rapid quantification of ex vivo parasite growth. METHODS Field isolates from Papua, Indonesia, underwent ex vivo drug susceptibility testing against chloroquine, amodiaquine, piperaquine, mefloquine, and artesunate. A single nucleic acid stain (i.e., hydroethidine (HE) for P. falciparum and SYBR Green I (SG) for P. vivax) was used to quantify infected red blood cells by FC-based signal detection. Data derived by FC were compared to standard quantification by light microscopy (LM). A subset of isolates was used to compare single and double staining techniques. RESULTS In total, 57 P. falciparum and 23 P. vivax field isolates were collected for ex vivo drug susceptibility testing. Reliable paired data between LM and FC was obtained for 88 % (295/334) of these assays. The median difference of derived IC50 values varied from -5.4 to 6.1 nM, associated with 0.83-1.23 fold change in IC50 values between LM and FC. In 15 assays (5.1 %), the derived difference of IC50 estimates was beyond the 95 % limits of agreement; in eleven assays (3.7 %), this was attributable to low parasite growth (final schizont count < 40 %), and in four assays (1.4 %) due to low initial parasitaemia at the start of assay (<2000 µl(-1)). In a subset of seven samples, LM, single and double staining FC techniques generated similar IC50 values. CONCLUSIONS A single staining FC-based assay using a portable cytometer provides a simple, fast and versatile platform for field surveillance of ex vivo drug susceptibility in clinical P. falciparum and P. vivax isolates.
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Affiliation(s)
- Grennady Wirjanata
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia. .,Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia.
| | - Irene Handayuni
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia.
| | - Pak Prayoga
- Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia.
| | - Dwi Apriyanti
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta, 10430, Indonesia.
| | - Ferryanto Chalfein
- Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia.
| | - Boni F Sebayang
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta, 10430, Indonesia.
| | - Steven Kho
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia.
| | - Rintis Noviyanti
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta, 10430, Indonesia.
| | - Enny Kenangalem
- Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia. .,District Health Authority, Timika, Papua, Indonesia.
| | - Brice Campo
- Medicines for Malaria Venture (MMV), 20 rte de Pré-Bois, PO Box 1826, 1215, Geneva 15, Switzerland.
| | - Jeanne Rini Poespoprodjo
- Papuan Health and Community Development Foundation (PHCDF), Timika, Papua, Indonesia. .,District Health Authority, Timika, Papua, Indonesia. .,Department of Paediatrics, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Indonesia.
| | - Ric N Price
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia. .,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
| | - Jutta Marfurt
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, 0811, Darwin, Australia.
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Ang MLT, Murima P, Pethe K. Next-generation antimicrobials: from chemical biology to first-in-class drugs. Arch Pharm Res 2015; 38:1702-17. [PMID: 26259630 PMCID: PMC4567591 DOI: 10.1007/s12272-015-0645-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/29/2015] [Indexed: 01/11/2023]
Abstract
The global emergence of multi-drug resistant bacteria invokes an urgent and imperative necessity for the identification of novel antimicrobials. The general lack of success in progressing novel chemical entities from target-based drug screens have prompted calls for radical and innovative approaches for drug discovery. Recent developments in chemical biology and target deconvolution strategies have revived interests in the utilization of whole-cell phenotypic screens and resulted in several success stories for the discovery and development novel drug candidates and target pathways. In this review, we present and discuss recent chemical biology approaches focusing on the discovery of novel targets and new lead molecules for the treatment of human bacterial and protozoan infections.
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Affiliation(s)
- Michelle Lay Teng Ang
- Lee Kong Chian School of Medicine and School of Biological Sciences, Nanyang Technological University, 30 Biopolis Street, #B2-15a, Singapore, 138671, Singapore.
| | - Paul Murima
- Global Health Institute, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Kevin Pethe
- Lee Kong Chian School of Medicine and School of Biological Sciences, Nanyang Technological University, 30 Biopolis Street, #B2-15a, Singapore, 138671, Singapore.
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Morphological and Molecular Descriptors of the Developmental Cycle of Babesia divergens Parasites in Human Erythrocytes. PLoS Negl Trop Dis 2015; 9:e0003711. [PMID: 25955414 PMCID: PMC4425553 DOI: 10.1371/journal.pntd.0003711] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 03/19/2015] [Indexed: 11/19/2022] Open
Abstract
Human babesiosis, especially caused by the cattle derived Babesia divergens parasite, is on the increase, resulting in renewed attentiveness to this potentially life threatening emerging zoonotic disease. The molecular mechanisms underlying the pathophysiology and intra-erythrocytic development of these parasites are poorly understood. This impedes concerted efforts aimed at the discovery of novel anti-babesiacidal agents. By applying sensitive cell biological and molecular functional genomics tools, we describe the intra-erythrocytic development cycle of B. divergens parasites from immature, mono-nucleated ring forms to bi-nucleated paired piriforms and ultimately multi-nucleated tetrads that characterizes zoonotic Babesia spp. This is further correlated for the first time to nuclear content increases during intra-erythrocytic development progression, providing insight into the part of the life cycle that occurs during human infection. High-content temporal evaluation elucidated the contribution of the different stages to life cycle progression. Moreover, molecular descriptors indicate that B. divergens parasites employ physiological adaptation to in vitro cultivation. Additionally, differential expression is observed as the parasite equilibrates its developmental stages during its life cycle. Together, this information provides the first temporal evaluation of the functional transcriptome of B. divergens parasites, information that could be useful in identifying biological processes essential to parasite survival for future anti-babesiacidal discoveries.
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Peatey CL, Chavchich M, Chen N, Gresty KJ, Gray KA, Gatton ML, Waters NC, Cheng Q. Mitochondrial Membrane Potential in a Small Subset of Artemisinin-Induced Dormant Plasmodium falciparum Parasites In Vitro. J Infect Dis 2015; 212:426-34. [PMID: 25635122 DOI: 10.1093/infdis/jiv048] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/20/2015] [Indexed: 11/12/2022] Open
Abstract
Artemisinin-induced dormancy is a proposed mechanism for failures of monotherapy and is linked with artemisinin resistance in Plasmodium falciparum. The biological characterization and dynamics of dormant parasites are not well understood. Here we report that after dihydroartemisinin treatment in vitro, a small subset of morphologically dormant parasites was stained with rhodamine 123 (RH), a mitochondrial membrane potential marker, and persisted to recovery. RH-positive parasites sorted with fluorescence-activated cell sorting resumed growth at 10,000/well whereas RH-negative parasites failed to recover at 5 million/well. Furthermore, transcriptional activity for mitochondrial enzymes was detected only in RH-positive dormant parasites. Importantly, after treatment of dormant parasites with different concentrations of atovaquone, a mitochondrial inhibitor, the recovery of dormant parasites was delayed or stopped. This demonstrates that mitochondrial activity is critical for survival and regrowth of dormant parasites and that RH staining provides a means of identifying these parasites. These findings provide novel paths for studying and eradicating this dormant stage.
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Affiliation(s)
- Christopher L Peatey
- Drug Resistance and Diagnostics, Australian Army Malaria Institute Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute
| | - Marina Chavchich
- Drug Resistance and Diagnostics, Australian Army Malaria Institute
| | - Nanhua Chen
- Drug Resistance and Diagnostics, Australian Army Malaria Institute
| | - Karryn J Gresty
- Drug Resistance and Diagnostics, Australian Army Malaria Institute Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute
| | - Karen-Ann Gray
- Drug Resistance and Diagnostics, Australian Army Malaria Institute Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute
| | - Michelle L Gatton
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, Australia
| | - Norman C Waters
- Walter Reed Army Institute of Research, Malaria Vaccine Branch, Military Malaria Research Program, Silver Spring, Maryland
| | - Qin Cheng
- Drug Resistance and Diagnostics, Australian Army Malaria Institute Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute
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Faria J, Moraes CB, Song R, Pascoalino BS, Lee N, Siqueira-Neto JL, Cruz DJM, Parkinson T, Ioset JR, Cordeiro-da-Silva A, Freitas-Junior LH. Drug discovery for human African trypanosomiasis: identification of novel scaffolds by the newly developed HTS SYBR Green assay for Trypanosoma brucei. ACTA ACUST UNITED AC 2014; 20:70-81. [PMID: 25342146 DOI: 10.1177/1087057114556236] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Human African trypanosomiasis (HAT) is a vector-transmitted tropical disease caused by the protozoan parasite Trypanosoma brucei. High-throughput screening (HTS) of small-molecule libraries in whole-cell assays is one of the most frequently used approaches in drug discovery for infectious diseases. To aid in drug discovery efforts for HAT, the SYBR Green assay was developed for T. brucei in a 384-well format. This semi-automated assay is cost- and time-effective, robust, and reproducible. The SYBR Green assay was compared to the resazurin assay by screening a library of 4000 putative kinase inhibitors, revealing a superior performance in terms of assay time, sensitivity, simplicity, and reproducibility, and resulting in a higher hit confirmation rate. Although the resazurin assay allows for comparatively improved detection of slow-killing compounds, it also has higher false-positive rates that are likely to arise from the assay experimental conditions. The compounds with the most potent antitrypanosomal activity were selected in both screens and grouped into 13 structural clusters, with 11 new scaffolds as antitrypanosomal agents. Several of the identified compounds had IC50 <1 µM coupled with high selectivity toward the parasite. The core structures of the scaffolds are shown, providing promising new starting points for drug discovery for HAT.
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Affiliation(s)
- Joana Faria
- Center for Neglected Diseases Drug Discovery (CND3), Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, South Korea Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Carolina B Moraes
- Center for Neglected Diseases Drug Discovery (CND3), Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, South Korea Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas-SP, Brazil
| | - Rita Song
- MedChem & Chemical Biology Group, Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, South Korea
| | - Bruno S Pascoalino
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas-SP, Brazil
| | - Nakyung Lee
- Center for Neglected Diseases Drug Discovery (CND3), Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, South Korea
| | - Jair L Siqueira-Neto
- Center for Neglected Diseases Drug Discovery (CND3), Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, South Korea Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego, La Jolla, CA, USA
| | - Deu John M Cruz
- Center for Neglected Diseases Drug Discovery (CND3), Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, South Korea
| | - Tanya Parkinson
- Drugs for Neglected Diseases initiative (DNDi), Geneva, Switzerland
| | | | - Anabela Cordeiro-da-Silva
- Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Lucio H Freitas-Junior
- Center for Neglected Diseases Drug Discovery (CND3), Institut Pasteur Korea, Seongnam-si, Gyeonggi-do, South Korea Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas-SP, Brazil
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High-throughput tri-colour flow cytometry technique to assess Plasmodium falciparum parasitaemia in bioassays. Malar J 2014; 13:412. [PMID: 25331683 PMCID: PMC4213491 DOI: 10.1186/1475-2875-13-412] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 10/09/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Unbiased flow cytometry-based methods have become the technique of choice in many laboratories for high-throughput, accurate assessments of malaria parasites in bioassays. A method to quantify live parasites based on mitotracker red CMXRos was recently described but consistent distinction of early ring stages of Plasmodium falciparum from uninfected red blood cells (uRBC) remains a challenge. METHODS Here, a high-throughput, three-parameter (tri-colour) flow cytometry technique based on mitotracker red dye, the nucleic acid dye coriphosphine O (CPO) and the leucocyte marker CD45 for enumerating live parasites in bioassays was developed. The technique was applied to estimate the specific growth inhibition index (SGI) in the antibody-dependent cellular inhibition (ADCI) assay and compared to parasite quantification by microscopy and mitotracker red staining. The Bland-Altman analysis was used to compare biases between SGI estimated by the tri-colour staining technique, mitotracker red and by microscopy. RESULTS CPO allowed a better separation between early rings and uRBCs compared to mitotracker red resulting in a more accurate estimate of total parasitaemia. The tri-colour technique is rapid, cost effective and robust with comparable sensitivity to microscopy and capable of discriminating between live and dead and/or compromised parasites. Staining for CD45 improved parasitaemia estimates in ADCI assay since high numbers of leucocytes interfered with the accurate identification of parasitized RBC. The least bias (-1.60) in SGI was observed between the tri-colour and microscopy. CONCLUSION An improved methodology for high-throughput assessment of P. falciparum parasitaemia under culture conditions that could be useful in different bioassays, including ADCI and growth inhibition assays has been developed.
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Fréville A, Tellier G, Vandomme A, Pierrot C, Vicogne J, Cantrelle FX, Martoriati A, Cailliau-Maggio K, Khalife J, Landrieu I. Identification of a Plasmodium falciparum inhibitor-2 motif involved in the binding and regulation activity of protein phosphatase type 1. FEBS J 2014; 281:4519-34. [PMID: 25132288 DOI: 10.1111/febs.12960] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 07/25/2014] [Accepted: 08/05/2014] [Indexed: 11/28/2022]
Abstract
The regulation of Plasmodium falciparum protein phosphatase type 1 (PfPP1) activity remains to be deciphered. Data from homologous eukaryotic type 1 protein phosphatases (PP1) suggest that several protein regulators should be involved in this essential process. One such regulator, named PfI2 based on its primary sequence homology with eukaryotic inhibitor 2 (I2), was recently shown to be able to interact with PfPP1 and to inhibit its phosphatase activity, mainly through the canonical 'RVxF' binding motif. The details of the structural and functional characteristics of this interaction are investigated here. Using NMR spectroscopy, a second site of interaction is suggested to reside between residues D94 and T117 and contains the 'FxxR/KxR/K' binding motif present in other I2 proteins. This site seems to play in concert/synergy with the 'RVxF' motif to bind PP1, because only mutations in both motifs were able to abolish this interaction completely. However, regarding the structure/function relationship, mutation of either the 'RVxF' or 'FxxR/KxR/K' motif is more drastic, because each mutation prevents the capacity of PfI2 to trigger germinal vesicle breakdown in microinjected Xenopus oocytes. This indicates that the tight association of the PfI2 regulator to PP1, mediated by a two-site interaction, is necessary to exert its function. Based on these results, the use of a peptide derived from the 'FxxR/KxR/K' PfI2 motif was investigated for its potential effect on Plasmodium growth. This peptide, fused at its N-terminus to a penetrating sequence, was shown to accumulate specifically in infected erythrocytes and to have an antiplasmodial effect.
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Affiliation(s)
- Aline Fréville
- Center for Infection and Immunity of Lille, Inserm U1019-CNRS UMR 8204, Université Lille Nord de France, Institut Pasteur de Lille, France
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In vitro antiplasmodial activities and synergistic combinations of differential solvent extracts of the polyherbal product, Nefang. BIOMED RESEARCH INTERNATIONAL 2014; 2014:835013. [PMID: 24877138 PMCID: PMC4022163 DOI: 10.1155/2014/835013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 04/04/2014] [Indexed: 11/17/2022]
Abstract
Nefang, a polyherbal product composed of Mangifera indica (bark and leaf), Psidium guajava, Carica papaya, Cymbopogon citratus, Citrus sinensis, and Ocimum gratissimum (leaves), is a potential therapy against P. falciparum malaria. In vitro antiplasmodial activities of its constituent solvent extracts were analyzed on CQ-sensitive (3D7) and multidrug resistant (Dd2) P. falciparum strains. The interactions involving the differential solvent extracts were further analyzed using a variable potency ratio drug combination approach. Effective concentration 50 (EC50) values were determined by nonlinear regression curve-fitting of the dose-response data and used in calculating the fractional inhibitory concentration 50 (FIC50) and combination indices (CI) for each pair. The derived EC50 values (3D7/Dd2, μg/mL) are Nefang-96.96/55.08, MiB-65.33/34.58, MiL-82.56/40.04, Pg-47.02/25.79, Cp-1188/317.5, Cc-723.3/141, Cs-184.4/105.1, and Og-778.5/118.9. Synergism was obtained with MiB/Pg (CI = 0.351), MiL/Pg (0.358), MiB/Cs (0.366), MiL/Cs (0.482), Pg/Cs (0.483), and Cs/Og (0.414) when analyzed at equipotency ratios. Cytotoxicity testing of Nefang and the solvent extracts on two human cell lines (Hep G2 and U2OS) revealed no significant toxicity relative to their antiplasmodial activities (SI > 20). Taken together, our data confirm the antimalarial activities of Nefang and its
constituent plant extracts and identified extract pairs with promising synergistic interactions for exploitation towards a rational phytotherapeutic and evidence-based antimalarial drug discovery.
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Shapiro HM, Apte SH, Chojnowski GM, Hänscheid T, Rebelo M, Grimberg BT. Cytometry in malaria--a practical replacement for microscopy? ACTA ACUST UNITED AC 2014; Chapter 11:11.20.1-11.20.23. [PMID: 23835802 DOI: 10.1002/0471142956.cy1120s65] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Malaria, caused by protozoan Plasmodium parasites, kills ~800,000 people each year. Exact figures are uncertain because presumptive diagnoses are often made without identifying parasites in patients' blood either by microscopy, using Giemsa's century-old stain, or by simpler tests that are ultimately dependent on microscopy for quality control. Microscopy itself relies on trained observers' ability to detect subtle morphological features of parasitized red blood cells, only a few of which may be present on a slide. Quantitative and objective flow cytometric measurements of cellular constituents such as DNA, RNA, and the malaria pigment hemozoin are now useful in research in malaria biology and pharmacology, and can provide more reliable identification of parasite species and developmental stages and better detection of low-density parasitemia than could microscopy. The same measurements can now be implemented in much smaller, simpler, cheaper imaging cytometers, potentially providing a more accurate and precise diagnostic modality.
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Wilson PT, Malhotra I, Mungai P, King CL, Dent AE. Transplacentally transferred functional antibodies against Plasmodium falciparum decrease with age. Acta Trop 2013; 128:149-53. [PMID: 23911334 DOI: 10.1016/j.actatropica.2013.07.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 07/17/2013] [Accepted: 07/21/2013] [Indexed: 11/16/2022]
Abstract
Transplacental transfer of antibodies from clinically malaria immune pregnant women to their fetuses is thought to provide passive protection against malaria during infancy. However, the presences and duration of functional antibodies against Plasmodium falciparum (Pf) in newborns has not been described. We used growth inhibition assays (GIA) to measure total anti-malaria functional antibodies present at birth and over the following year. Samples were drawn from cord blood (n=86) and in infants at six and 12 months of life (n=86 and 65 respectively). Three laboratory Pf strains (D10, W2mef, 3D7) and a field isolate (Msambweni 2006) were used in the assays. Median (ranges) GIA levels for cord plasma differed between laboratory parasite strains: D10, 0% (0-81); W2mef, 6% (0-80); 3D7, 18% (0-88); Msambweni 2006, 6% (0-43) (P<0.001, Wilcoxon signed-rank test). GIA levels against all Pf strains were found to decline in infants from birth to six months (P<0.01, Wilcoxon, signed-rank test). Functional antibodies as measured by GIA are transferred to the fetus and wane in the infants over time. Infant protection from clinical malaria disease may in part be mediated by these functional anti-malaria antibodies.
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Affiliation(s)
- Patrick T Wilson
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA.
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Teguh SC, Klonis N, Duffy S, Lucantoni L, Avery VM, Hutton CA, Baell JB, Tilley L. Novel Conjugated Quinoline–Indoles Compromise Plasmodium falciparum Mitochondrial Function and Show Promising Antimalarial Activity. J Med Chem 2013; 56:6200-15. [DOI: 10.1021/jm400656s] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - Sandra Duffy
- Eskitis Institute for Drug Discovery, Brisbane Innovation Park, Griffith University,
Nathan QLD 4111, Australia
| | - Leonardo Lucantoni
- Eskitis Institute for Drug Discovery, Brisbane Innovation Park, Griffith University,
Nathan QLD 4111, Australia
| | - Vicky M. Avery
- Eskitis Institute for Drug Discovery, Brisbane Innovation Park, Griffith University,
Nathan QLD 4111, Australia
| | | | - Jonathan B. Baell
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Science, Parkville
VIC 3052, Australia
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Fréville A, Cailliau-Maggio K, Pierrot C, Tellier G, Kalamou H, Lafitte S, Martoriati A, Pierce RJ, Bodart JF, Khalife J. Plasmodium falciparum encodes a conserved active inhibitor-2 for Protein Phosphatase type 1: perspectives for novel anti-plasmodial therapy. BMC Biol 2013; 11:80. [PMID: 23837822 PMCID: PMC3735429 DOI: 10.1186/1741-7007-11-80] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 06/18/2013] [Indexed: 01/21/2023] Open
Abstract
Background It is clear that the coordinated and reciprocal actions of kinases and phosphatases are fundamental in the regulation of development and growth of the malaria parasite. Protein Phosphatase type 1 is a key enzyme playing diverse and essential roles in cell survival. Its dephosphorylation activity/specificity is governed by the interaction of its catalytic subunit (PP1c) with regulatory proteins. Among these, inhibitor-2 (I2) is one of the most evolutionarily ancient PP1 regulators. In vivo studies in various organisms revealed a defect in chromosome segregation and cell cycle progression when the function of I2 is blocked. Results In this report, we present evidence that Plasmodium falciparum, the causative agent of the most deadly form of malaria, expresses a structural homolog of mammalian I2, named PfI2. Biochemical, in vitro and in vivo studies revealed that PfI2 binds PP1 and inhibits its activity. We further showed that the motifs 12KTISW16 and 102HYNE105 are critical for PfI2 inhibitory activity. Functional studies using the Xenopus oocyte model revealed that PfI2 is able to overcome the G2/M cell cycle checkpoint by inducing germinal vesicle breakdown. Genetic manipulations in P. falciparum suggest an essential role of PfI2 as no viable mutants with a disrupted PfI2 gene were detectable. Additionally, peptides derived from PfI2 and competing with RVxF binding sites in PP1 exhibit anti-plasmodial activity against blood stage parasites in vitro. Conclusions Taken together, our data suggest that the PfI2 protein could play a role in the regulation of the P. falciparum cell cycle through its PfPP1 phosphatase regulatory activity. Structure-activity studies of this regulator led to the identification of peptides with anti-plasmodial activity against blood stage parasites in vitro suggesting that PP1c-regulator interactions could be a novel means to control malaria.
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Affiliation(s)
- Aline Fréville
- Center for Infection and Immunity of Lille, Inserm U1019-CNRS UMR 8204, University of Lille Nord de France, Institut Pasteur de Lille, 1 Rue du Professeur Calmette, 59019 Lille, Cedex, France.
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Sir2a regulates rDNA transcription and multiplication rate in the human malaria parasite Plasmodium falciparum. Nat Commun 2013; 4:1530. [PMID: 23443558 PMCID: PMC3586713 DOI: 10.1038/ncomms2539] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/24/2013] [Indexed: 01/09/2023] Open
Abstract
The Plasmodium falciparum histone deacetylase Sir2a localizes at telomeric regions where it contributes to epigenetic silencing of clonally variant virulence genes. Apart from telomeres, PfSir2a also accumulates in the nucleolus, which harbours the developmentally regulated ribosomal RNA genes. Here we investigate the nucleolar function of PfSir2a and demonstrate that PfSir2a fine-tunes ribosomal RNA gene transcription. Using a parasite line in which PfSir2a has been disrupted, we observe that histones near the transcription start sites of all ribosomal RNA genes are hyperacetylated and that transcription of ribosomal RNA genes is upregulated. Complementation of the PfSir2a-disrupted parasites restores the ribosomal RNA levels, whereas PfSir2a overexpression in wild-type parasites decreases ribosomal RNA synthesis. Furthermore, we observe that PfSir2a modulation of ribosomal RNA synthesis is linked to an altered number of daughter merozoites and the parasite multiplication rate. These findings provide new insights into an epigenetic mechanism that controls malaria parasite proliferation and virulence. The factors that modulate growth rate of the human malaria parasite Plasmodium falciparum remain poorly understood. Here Scherf and collaborators demonstrate that the Plasmodium sirtuin PfSir2a regulates the transcription of ribosomal DNA, thereby modulating parasite proliferation rate and virulence.
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Asahi H, Tolba MEM, Tanabe M, Ohmae H. Molecular factors that are associated with early developmental arrest of intraerythrocytic Plasmodium falciparum. Can J Microbiol 2013; 59:485-93. [PMID: 23826958 DOI: 10.1139/cjm-2013-0166] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Malaria continues to be a devastating disease. We investigated the factors that control intraerythrocytic development of the parasite Plasmodium falciparum by using a chemically defined medium (CDM) containing non-esterified fatty acid(s) (NEFA) and phospholipids with specific fatty acid moieties, to identify substances crucial for parasite development. Different NEFAs in the CDM played distinct roles by altering the development of the parasite at various stages, with effects ranging from complete growth to growth arrest at the ring stage. We used genome-wide transcriptome profiling to identify genes that were differentially expressed among the different developmental stages of the parasite, cultured in the presence of various NEFAs. We predicted 26 transcripts that were associated with the suppression of schizogony, of which 5 transcripts, including merozoite surface protein 2, a putative DEAD/DEAH box RNA helicase, serine repeat antigen 3, a putative copper channel, and palmitoyl acyltransferase, were particularly associated with blockage of trophozoite progression from the ring stage. Furthermore, the involvement of copper ions in developmental arrest was detected by copper-ion-chelating methods, implying a critical function of copper homeostasis in the early growth stage of the parasite. These results should help to elucidate the mechanisms behind the development of P. falciparum.
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Affiliation(s)
- Hiroko Asahi
- Department of Parasitology, National Institute of Infectious Diseases, 23-1 Toyama 1-chome, Shinjuku-ku, Tokyo 162-8640, Japan.
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Alcantara LM, Kim J, Moraes CB, Franco CH, Franzoi KD, Lee S, Freitas-Junior LH, Ayong LS. Chemosensitization potential of P-glycoprotein inhibitors in malaria parasites. Exp Parasitol 2013; 134:235-43. [PMID: 23541983 DOI: 10.1016/j.exppara.2013.03.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 03/05/2013] [Accepted: 03/17/2013] [Indexed: 01/24/2023]
Abstract
Members of the ATP-binding cassette (ABC)-type transporter superfamily have been implicated in multidrug resistance in malaria, and various mechanistic models have been postulated to explain their interaction with diverse antimalarial drugs. To gain insight into the pharmacological benefits of inhibiting ABC-type transporters in malaria chemotherapy, we investigated the in vitro chemosensitization potential of various P-glycoprotein inhibitors. A fluorescent chloroquine derivative was synthesized and used to assess the efflux dynamics of chloroquine in MDR and wild type Plasmodium falciparum parasites. This novel BODIPY-based probe accumulated in the digestive vacuole (DV) of CQ-sensitive parasites but less so in MDR cells. Pre-exposure of the MDR parasites to non-cytocidal concentrations of unlabeled chloroquine resulted in a diffused cytoplasmic retention of the probe whereas a similar treatment with the CQR-reversing agent, chlorpheniramine, resulted in DV accumulation. A diffused cytoplasmic distribution of the probe was also obtained following treatment with the P-gp specific inhibitors zosuquidar and tariquidar, whereas treatments with the tyrosine kinase inhibitors gefitinib or imatinib produced a partial accumulation within the DV. Isobologram analyses of the interactions between these inhibitors and the antimalarial drugs chloroquine, mefloquine, and artemisinin revealed distinct patterns of drug synergism, additivity and antagonism. Taken together, the data indicate that competitive tyrosine kinase and noncompetitive P-glycoprotein ATPase-specific inhibitors represent two new classes of chemosensitizing agents in malaria parasites, but caution against the indiscriminate use of these agents in antimalarial drug combinations.
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Affiliation(s)
- Laura M Alcantara
- Center for Neglected Diseases Drug Discovery, Institut Pasteur Korea, Sampyeong-dong 696, Bundang-gu, Seongnam-si, Gyeonggi-do 463-400, Republic of Korea
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Aggrey AA, Srivastava K, Ture S, Field DJ, Morrell CN. Platelet induction of the acute-phase response is protective in murine experimental cerebral malaria. THE JOURNAL OF IMMUNOLOGY 2013; 190:4685-91. [PMID: 23536632 DOI: 10.4049/jimmunol.1202672] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Platelets are most recognized as the cellular mediator of thrombosis, but they are increasingly appreciated for their immunomodulatory roles, including responses to Plasmodium infection. Platelet interactions with endothelial cells and leukocytes contribute significantly to the pathogenesis of experimental cerebral malaria (ECM). Recently, it has been suggested that platelets not only have an adverse role in cerebral malaria, but platelets may also be protective in animal models of uncomplicated malaria. We now demonstrate that these diverse and seemingly contradictory roles for platelets extend to cerebral malaria models and are dependent on the timing of platelet activation during infection. Our data show that platelets are activated very early in ECM and have a central role in initiation of the acute-phase response to blood-stage infection. Unlike platelet depletion or inhibition postinfection, preinfection platelet depletion or treatment with a platelet inhibitor is not protective. Additionally, we show that platelet-driven acute-phase responses have a major role in protecting mice from ECM by limiting parasite growth. Our data now suggest that platelets have a complex role in ECM pathogenesis: platelets help limit parasite growth early postinfection, but with continued platelet activation as the disease progresses, platelets contribute to ECM-associated inflammation.
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Affiliation(s)
- Angela A Aggrey
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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45
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Kwansa-Bentum B, Izumiyama S, Kitamura K, Obata-Ninomiya K, Ohta N, Asahi H. Comparative studies of serum-free media and detection techniques for <i>in vitro</i> drug sensitivity assessment of <i>Plasmodium falciparum</i>. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ojcd.2013.33020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Mefloquine exposure induces cell cycle delay and reveals stage-specific expression of the pfmdr1 gene. Antimicrob Agents Chemother 2012. [PMID: 23208721 DOI: 10.1128/aac.01006-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Drug-resistant Plasmodium falciparum malaria is a major public health problem. An elevated pfmdr1 gene copy number (CN) is known to decrease parasite sensitivity to the commonly used antimalarial mefloquine (MFQ). To understand the relationship between pfmdr1 CN and mefloquine resistance, we evaluated pfmdr1 transcript levels in three P. falciparum strains with different CNs in the presence and absence of MFQ. Parasite strains with multiple pfmdr1 gene copies exhibited higher relative transcript levels than single-copy parasites, and MFQ induced pfmdr1 expression above the levels without treatment in all three strains evaluated. Concomitant morphology analyses of the sampled cultures revealed that MFQ treatment of synchronized ring-stage parasites induced a delay in parasite maturation through the intraerythrocytic cycle. pfmdr1 expression peaks in the ring stage, and MFQ could be causing increased transcription by delaying parasite maturation. However, pretreatment with mefloquine did not affect the artemisinin in vitro half-maximal inhibitory concentration (IC(50)). These results suggest that MFQ-induced increases in pfmdr1 expression are the direct result of the maturation delay at the ring stage but that this change in expression does not affect the antimalarial activity of artemisinin.
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Philipp S, Oberg HH, Janssen O, Leippe M, Gelhaus C. Isolation of erythrocytes infected with viable early stages of Plasmodium falciparum by flow cytometry. Cytometry A 2012; 81:1048-54. [PMID: 23136095 DOI: 10.1002/cyto.a.22226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 09/18/2012] [Accepted: 10/10/2012] [Indexed: 11/05/2022]
Abstract
The erythrocytic life cycle of Plasmodium falciparum is highly associated with severe clinical symptoms of malaria that causes hundreds of thousands of death each year. The parasite develops within human erythrocytes leading to the disruption of the infected red blood cell (iRBC) prior to the start of a new cycle of erythrocyte infection. Emerging mechanisms of resistance against antimalarial drugs require improved knowledge about parasite's blood stages to facilitate new alternative antimalarial strategies. For the analysis of young blood stages of Plasmodium at the molecular level, the isolation of ring stages is essential. However, early stages can hardly be separated from both, late stages and non-infected red blood cells using conventional methods. Here, iRBCs were stained with the DNA-binding dyes Vybrant® DyeCycle™ Violet and SYBR® Green I. Subsequently, cells were subjected to flow-cytometric analysis. This enabled the discrimination of early stage iRBCs as well as late-stage iRBCs from non-infected erythrocytes and the properties of the used dyes were evaluated. Moreover, early stage iRBCs were isolated with high purity (>98%) by FACS. Subsequently, development of sorted early stages of the parasite was monitored over time and compared with control cultures. The described flow cytometry method, based on staining with Vybrant DyeCycle Violet, allows the isolation of viable ring stages of the malarial agent P. falciparum, and thereby provides the basis for new, broad-range molecular investigations of the parasite.
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Affiliation(s)
- Stephan Philipp
- Department of Zoophysiology, Zoological Institute, University of Kiel, Kiel 24098, Germany.
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Aguiar ACC, Rocha EMMD, Souza NBD, França TCC, Krettli AU. New approaches in antimalarial drug discovery and development: a review. Mem Inst Oswaldo Cruz 2012; 107:831-45. [DOI: 10.1590/s0074-02762012000700001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 08/16/2012] [Indexed: 01/22/2023] Open
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Jogdand PS, Singh SK, Christiansen M, Dziegiel MH, Singh S, Theisen M. Flow cytometric readout based on Mitotracker Red CMXRos staining of live asexual blood stage malarial parasites reliably assesses antibody dependent cellular inhibition. Malar J 2012; 11:235. [PMID: 22818754 PMCID: PMC3418546 DOI: 10.1186/1475-2875-11-235] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 07/20/2012] [Indexed: 11/10/2022] Open
Abstract
Background Functional in vitro assays could provide insights into the efficacy of malaria vaccine candidates. For estimating the anti-parasite effect induced by a vaccine candidate, an accurate determination of live parasite count is an essential component of most in vitro bioassays. Although traditionally parasites are counted microscopically, a faster, more accurate and less subjective method for counting parasites is desirable. In this study mitochondrial dye (Mitotracker Red CMXRos) was used for obtaining reliable live parasite counts through flow cytometry. Methods Both asynchronous and tightly synchronized asexual blood stage cultures of Plasmodium falciparum were stained with CMXRos and subjected to detection by flow cytometry and fluorescence microscopy. The parasite counts obtained by flow cytometry were compared to standard microscopic counts obtained through examination of Giemsa-stained thin smears. A comparison of the ability of CMXRos to stain live and compromised parasites (induced by either medium starvation or by anti-malarial drug treatment) was carried out. Finally, parasite counts obtained by CMXRos staining through flow cytometry were used to determine specific growth inhibition index (SGI) in an antibody-dependent cellular inhibition (ADCI) assay. Results Mitotracker Red CMXRos can reliably detect live intra-erythrocytic stages of P. falciparum. Comparison between staining of live with compromised parasites shows that CMXRos predominantly stains live parasites with functional mitochondria. Parasite counts obtained by CMXRos staining and flow cytometry were highly reproducible and can reliably determine the ability of IgG from hyper-immune individuals to inhibit parasite growth in presence of monocytes in ADCI assay. Further, a dose-dependent parasite growth inhibitory effect could be detected for both total IgG purified from hyper-immune sera and affinity purified IgGs against the N-terminal non-repeat region of GLURP in ADCI assays coupled with determination of parasite counts through CMXRos staining and flow cytometry. Conclusions A flow cytometry method based on CMXRos staining for detection of live parasite populations has been optimized. This is a rapid and sensitive method with high inter-assay reproducibility which can reliably determine the anti-parasite effect mediated by antibodies in functional in vitro assays such as ADCI assay.
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Affiliation(s)
- Prajakta S Jogdand
- Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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Somsak V, Srichairatanakool S, Yuthavong Y, Kamchonwongpaisan S, Uthaipibull C. Flow cytometric enumeration of Plasmodium berghei-infected red blood cells stained with SYBR Green I. Acta Trop 2012; 122:113-8. [PMID: 22222185 DOI: 10.1016/j.actatropica.2011.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 12/19/2011] [Accepted: 12/21/2011] [Indexed: 01/21/2023]
Abstract
High-throughput methods for evaluation of in vivo efficacy of candidate compounds against Plasmodium parasites are necessary during the antimalarial drug development process. It is essential that enumeration of parasitemia in the infected blood from experimental host animals is accurate and reliable. Flow cytometric enumeration of parasitized cells stained with fluorescent dye is a rapid alternative method to conventional microscopic counting. In this study, a protocol for flow cytometric enumeration of rodent malaria parasite Plasmodium berghei-infected red blood cells (RBC) stained with SYBR Green I was developed. The optimal concentration of SYBR Green I used to stain infected RBC was 4× for 30 min. This SYBR Green I staining protocol in combination with the bi-dimensional FL-1(530)/FL-3(620) detection method accurately detects parasitemia above 0.02%. The dye is stable during the prolonged incubation period necessary for accurate enumeration of parasitemia, with no loss of fluorescent signal over a period of hours. This protocol was validated in an antimalarial assay and the result was comparable to that obtained from conventional microscopic counting. The SYBR Green I flow cytometric protocol is thus a rapid and precise tool for high-throughput in vivo antimalarial drug screening.
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Affiliation(s)
- Voravuth Somsak
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Pathumthani 12120, Thailand
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