101
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Kaur H, Machado M, de Kock C, Smith P, Chibale K, Prudêncio M, Singh K. Primaquine-pyrimidine hybrids: synthesis and dual-stage antiplasmodial activity. Eur J Med Chem 2015; 101:266-73. [PMID: 26142491 DOI: 10.1016/j.ejmech.2015.06.045] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 06/21/2015] [Accepted: 06/22/2015] [Indexed: 10/23/2022]
Abstract
A series of novel pyrimidine-primaquine hybrids were synthesized and their effectiveness against the blood and liver stages of malaria parasites was evaluated. The hybrids displayed enhanced liver stage in vitro activity against P. berghei liver stage infection.
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Affiliation(s)
- Hardeep Kaur
- Department of Chemistry, UGC-Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar 143005, India
| | - Marta Machado
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Carmen de Kock
- Division of Pharmacology, Department of Medicine, University of Cape Town, Observatory 7925, South Africa
| | - Peter Smith
- Division of Pharmacology, Department of Medicine, University of Cape Town, Observatory 7925, South Africa
| | - Kelly Chibale
- Department of Chemistry, South African Medical Research Council Drug Discovery and Development Research Unit, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 701, South Africa
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Kamaljit Singh
- Department of Chemistry, UGC-Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar 143005, India.
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102
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Inácio P, Zuzarte-Luís V, Ruivo MTG, Falkard B, Nagaraj N, Rooijers K, Mann M, Mair G, Fidock DA, Mota MM. Parasite-induced ER stress response in hepatocytes facilitates Plasmodium liver stage infection. EMBO Rep 2015; 16:955-64. [PMID: 26113366 DOI: 10.15252/embr.201439979] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 06/02/2015] [Indexed: 12/15/2022] Open
Abstract
Upon infection of a mammalian host, Plasmodium parasites first replicate inside hepatocytes, generating thousands of new parasites. Although Plasmodium intra-hepatic development represents a substantial metabolic challenge to the host hepatocyte, how infected cells respond to and integrate this stress remains poorly understood. Here, we present proteomic and transcriptomic analyses, revealing that the endoplasmic reticulum (ER)-resident unfolded protein response (UPR) is activated in host hepatocytes upon Plasmodium berghei infection. The expression of XBP1s--the active form of the UPR mediator XBP1--and the liver-specific UPR mediator CREBH is induced by P. berghei infection in vivo. Furthermore, this UPR induction increases parasite liver burden. Altogether, our data suggest that ER stress is a central feature of P. berghei intra-hepatic development, contributing to the success of infection.
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Affiliation(s)
- Patricia Inácio
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Vanessa Zuzarte-Luís
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Margarida T G Ruivo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Brie Falkard
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA
| | - Nagarjuna Nagaraj
- Department of Proteomics and Signal Transduction, Max Planck Institute for Biochemistry, Martinsried, Germany
| | - Koos Rooijers
- Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute for Biochemistry, Martinsried, Germany
| | - Gunnar Mair
- Department of Parasitology, University of Heidelberg, Heidelberg, Germany
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY, USA
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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103
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de Koning-Ward TF, Gilson PR, Crabb BS. Advances in molecular genetic systems in malaria. Nat Rev Microbiol 2015; 13:373-87. [DOI: 10.1038/nrmicro3450] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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104
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Siciliano G, Alano P. Enlightening the malaria parasite life cycle: bioluminescent Plasmodium in fundamental and applied research. Front Microbiol 2015; 6:391. [PMID: 26029172 PMCID: PMC4426725 DOI: 10.3389/fmicb.2015.00391] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/16/2015] [Indexed: 12/31/2022] Open
Abstract
The unicellular protozoan parasites of the genus Plasmodium impose on human health worldwide the enormous burden of malaria. The possibility to genetically modify several species of malaria parasites represented a major advance in the possibility to elucidate their biology and is now turning laboratory lines of transgenic Plasmodium into precious weapons to fight malaria. Amongst the various genetically modified plasmodia, transgenic parasite lines expressing bioluminescent reporters have been essential to unveil mechanisms of parasite gene expression and to develop in vivo imaging approaches in mouse malaria models. Mainly the human malaria parasite Plasmodium falciparum and the rodent parasite P. berghei have been engineered to express bioluminescent reporters in almost all the developmental stages of the parasite along its complex life cycle between the insect and the vertebrate hosts. Plasmodium lines expressing conventional and improved luciferase reporters are now gaining a central role to develop cell based assays in the much needed search of new antimalarial drugs and to open innovative approaches for both fundamental and applied research in malaria.
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Affiliation(s)
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di SanitàRome, Italy
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105
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Campo B, Vandal O, Wesche DL, Burrows JN. Killing the hypnozoite--drug discovery approaches to prevent relapse in Plasmodium vivax. Pathog Glob Health 2015; 109:107-22. [PMID: 25891812 PMCID: PMC4455353 DOI: 10.1179/2047773215y.0000000013] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The eradication of malaria will only be possible if effective, well-tolerated medicines kill hypnozoites in vivax and ovale malaria, and thus prevent relapses in patients. Despite progress in the 8-aminoquinoline series, with tafenoquine in Phase III showing clear benefits over primaquine, the drug discovery challenge to identify hypnozoiticidal or hypnozoite-activating compounds has been hampered by the dearth of biological tools and assays, which in turn has been limited by the immense scientific and logistical challenges associated with accessing relevant human tissue and sporozoites. This review summarises the existing drug discovery series and approaches concerning the goal to block relapse.
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Affiliation(s)
- Brice Campo
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Omar Vandal
- The Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - David L. Wesche
- The Bill and Melinda Gates Foundation, Seattle, WA, USA
- Great Lakes Drug Development/Certara, Princeton, NJ, USA
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106
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Kumar S, Kumari R, Pandey R. New insight-guided approaches to detect, cure, prevent and eliminate malaria. PROTOPLASMA 2015; 252:717-753. [PMID: 25323622 DOI: 10.1007/s00709-014-0697-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 09/01/2014] [Indexed: 06/04/2023]
Abstract
New challenges posed by the development of resistance against artemisinin-based combination therapies (ACTs) as well as previous first-line therapies, and the continuing absence of vaccine, have given impetus to research in all areas of malaria control. This review portrays the ongoing progress in several directions of malaria research. The variants of RTS,S and apical membrane antigen 1 (AMA1) are being developed and test adapted as multicomponent and multistage malaria control vaccines, while many other vaccine candidates and methodologies to produce antigens are under experimentation. To track and prevent the spread of artemisinin resistance from Southeast Asia to other parts of the world, rolling circle-enhanced enzyme activity detection (REEAD), a time- and cost-effective malaria diagnosis in field conditions, and a DNA marker associated with artemisinin resistance have become available. Novel mosquito repellents and mosquito trapping and killing techniques much more effective than the prevalent ones are undergoing field testing. Mosquito lines stably infected with their symbiotic wild-type or genetically engineered bacteria that kill sympatric malaria parasites are being constructed and field tested for stopping malaria transmission. A complementary approach being pursued is the addition of ivermectin-like drug molecules to ACTs to cure malaria and kill mosquitoes. Experiments are in progress to eradicate malaria mosquito by making it genetically male sterile. High-throughput screening procedures are being developed and used to discover molecules that possess long in vivo half life and are active against liver and blood stages for the fast cure of malaria symptoms caused by simple or relapsing and drug-sensitive and drug-resistant types of varied malaria parasites, can stop gametocytogenesis and sporogony and could be given in one dose. Target-based antimalarial drug designing has begun. Some of the putative next-generation antimalarials that possess in their scaffold structure several of the desired properties of malaria cure and control are exemplified by OZ439, NITD609, ELQ300 and tafenoquine that are already undergoing clinical trials, and decoquinate, usnic acid, torin-2, ferroquine, WEHI-916, MMV396749 and benzothiophene-type N-myristoyltransferase (NMT) inhibitors, which are candidates for future clinical usage. Among these, NITD609, ELQ300, decoquinate, usnic acid, torin-2 and NMT inhibitors not only cure simple malaria and are prophylactic against simple malaria, but they also cure relapsing malaria.
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Affiliation(s)
- Sushil Kumar
- SKA Institution for Research, Education and Development (SKAIRED), 4/11 SarvPriya Vihar, New Delhi, 110016, India,
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107
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De Niz M, Helm S, Horstmann S, Annoura T, del Portillo HA, Khan SM, Heussler VT. In vivo and in vitro characterization of a Plasmodium liver stage-specific promoter. PLoS One 2015; 10:e0123473. [PMID: 25874388 PMCID: PMC4398466 DOI: 10.1371/journal.pone.0123473] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 03/03/2015] [Indexed: 12/28/2022] Open
Abstract
Little is known about stage-specific gene regulation in Plasmodium parasites, in particular the liver stage of development. We have previously described in the Plasmodium berghei rodent model, a liver stage-specific (lisp2) gene promoter region, in vitro. Using a dual luminescence system, we now confirm the stage specificity of this promoter region also in vivo. Furthermore, by substitution and deletion analyses we have extended our in vitro characterization of important elements within the promoter region. Importantly, the dual luminescence system allows analyzing promoter constructs avoiding mouse-consuming cloning procedures of transgenic parasites. This makes extensive mutation and deletion studies a reasonable approach also in the malaria mouse model. Stage-specific expression constructs and parasite lines are extremely valuable tools for research on Plasmodium liver stage biology. Such reporter lines offer a promising opportunity for assessment of liver stage drugs, characterization of genetically attenuated parasites and liver stage-specific vaccines both in vivo and in vitro, and may be key for the generation of inducible systems.
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Affiliation(s)
- Mariana De Niz
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- * E-mail:
| | - Susanne Helm
- Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Sebastian Horstmann
- Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Takeshi Annoura
- Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Department of Parasitology, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Hernando A. del Portillo
- Barcelona Centre for International Health Research (CRESIB), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Shahid M. Khan
- Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
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108
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Lewis MD, Behrends J, Sá E Cunha C, Mendes AM, Lasitschka F, Sattler JM, Heiss K, Kooij TWA, Prudêncio M, Bringmann G, Frischknecht F, Mueller AK. Chemical attenuation of Plasmodium in the liver modulates severe malaria disease progression. THE JOURNAL OF IMMUNOLOGY 2015; 194:4860-70. [PMID: 25862814 DOI: 10.4049/jimmunol.1400863] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 03/11/2015] [Indexed: 11/19/2022]
Abstract
Cerebral malaria is one of the most severe complications of malaria disease, attributed to a complicated series of immune reactions in the host. The syndrome is marked by inflammatory immune responses, margination of leukocytes, and parasitized erythrocytes in cerebral vessels leading to breakdown of the blood-brain barrier. We show that chemical attenuation of the parasite at the very early, clinically silent liver stage suppresses parasite development, delays the time until parasites establish blood-stage infection, and provokes an altered host immune response, modifying immunopathogenesis and protecting from cerebral disease. The early response is proinflammatory and cell mediated, with increased T cell activation in the liver and spleen, and greater numbers of effector T cells, cytokine-secreting T cells, and proliferating, proinflammatory cytokine-producing T cells. Dendritic cell numbers, T cell activation, and infiltration of CD8(+) T cells to the brain are decreased later in infection, possibly mediated by the anti-inflammatory cytokine IL-10. Strikingly, protection can be transferred to naive animals by adoptive transfer of lymphocytes from the spleen at very early times of infection. Our data suggest that a subpopulation belonging to CD8(+) T cells as early as day 2 postinfection is responsible for protection. These data indicate that liver stage-directed early immune responses can moderate the overall downstream host immune response and modulate severe malaria outcome.
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Affiliation(s)
- Matthew D Lewis
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, D 69120 Heidelberg, Germany; German Centre for Infection Research, D 69120 Heidelberg, Germany
| | - Jochen Behrends
- Core Facility Fluorescence Cytometry, Research Center Borstel, D 23845 Borstel, Germany
| | - Cláudia Sá E Cunha
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - António M Mendes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Felix Lasitschka
- German Centre for Infection Research, D 69120 Heidelberg, Germany; Institute of Pathology, Heidelberg University Hospital, D 69120 Heidelberg, Germany
| | - Julia M Sattler
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, D 69120 Heidelberg, Germany
| | - Kirsten Heiss
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, D 69120 Heidelberg, Germany; MalVa GmbH, D 69121 Heidelberg, Germany
| | - Taco W A Kooij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, the Netherlands; Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, the Netherlands; and
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Gerhard Bringmann
- Institute for Organic Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Friedrich Frischknecht
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, D 69120 Heidelberg, Germany
| | - Ann-Kristin Mueller
- Centre for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, D 69120 Heidelberg, Germany; German Centre for Infection Research, D 69120 Heidelberg, Germany;
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109
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Matz JM, Kooij TWA. Towards genome-wide experimental genetics in the in vivo malaria model parasite Plasmodium berghei. Pathog Glob Health 2015; 109:46-60. [PMID: 25789828 DOI: 10.1179/2047773215y.0000000006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Plasmodium berghei was identified as a parasite of thicket rats (Grammomys dolichurus) and Anopheles dureni mosquitoes in African highland forests. Successful adaptation to a range of rodent and mosquito species established P. berghei as a malaria model parasite. The introduction of stable transfection technology, permitted classical reverse genetics strategies and thus systematic functional profiling of the gene repertoire. In the past 10 years following the publication of the P. berghei genome sequence, many new tools for experimental genetics approaches have been developed and existing ones have been improved. The infection of mice is the principal limitation towards a genome-wide repository of mutant parasite lines. In the past few years, there have been some promising and most welcome developments that allow rapid selection and isolation of recombinant parasites while simultaneously minimising animal usage. Here, we provide an overview of all the currently available tools and methods.
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110
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Rodrigues CAB, Frade RFM, Albuquerque IS, Perry MJ, Gut J, Machado M, Rosenthal PJ, Prudêncio M, Afonso CAM, Moreira R. Targeting the Erythrocytic and Liver Stages of Malaria Parasites withs-Triazine-Based Hybrids. ChemMedChem 2015; 10:883-90. [DOI: 10.1002/cmdc.201500011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 02/15/2015] [Indexed: 11/08/2022]
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111
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Taheri T, Saberi Nik H, Seyed N, Doustdari F, Etemadzadeh MH, Torkashvand F, Rafati S. Generation of stable L. major(+EGFP-LUC) and simultaneous comparison between EGFP and luciferase sensitivity. Exp Parasitol 2015; 150:44-55. [PMID: 25637784 DOI: 10.1016/j.exppara.2015.01.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 12/17/2014] [Accepted: 01/21/2015] [Indexed: 12/21/2022]
Abstract
Because of the lack of an accurate and sensitive tool to evaluate the parasitemia level, treatment or prevention of leishmaniasis remains an important challenge worldwide. To monitor and track leishmanial infection by two parameters in real time, we generated stably transgenic Leishmania that express a bi-reporter protein as fused EGFP and firefly luciferase. Using two reporter genes (egfp-luc) simultaneously increases the experimental sensitivity for detection/diagnosis, and in vitro quantification of parasites as well as real-time infection in mice. Through different specific tools, EGFP and LUC signals from the parasite were detectable and measurable within a mammalian host and promastigotes. Here, the LUC protein provided a higher level of sensitivity than did EGFP, so that infection was detectable at an earlier stage of the disease in the footpad (injection site) and lymph nodes by bioluminescence. These results depicted that: (1) both quantitative reporter genes, EGFP and LUC, could be simultaneously used to detect parasitemia in vitro and in vivo and (2) sensitivity of firefly luciferase was 10-fold higher than that of EGFP in promastigotes.
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Affiliation(s)
- Tahereh Taheri
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran.
| | - Hana Saberi Nik
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran; Fars Science and Research Branch, Islamic Azad University, Shiraz, Iran
| | - Negar Seyed
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
| | - Fatemeh Doustdari
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
| | | | - Fatemeh Torkashvand
- Department of Medical Biotechnology, Pasteur Institute of Iran, Tehran, Iran
| | - Sima Rafati
- Molecular Immunology and Vaccine Research Laboratory, Pasteur Institute of Iran, Tehran, Iran
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112
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Addition of histamine to subcutaneously injected Plasmodium berghei sporozoites increases the parasite liver load and could facilitate whole-parasite vaccination. Malar J 2015; 14:36. [PMID: 25627880 PMCID: PMC4318155 DOI: 10.1186/s12936-015-0552-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/06/2015] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Whole-parasite immunization remains the benchmark in malaria vaccine development. A major bottleneck in the translation of whole-parasite immunization towards routine vaccination is the mode of administration, since high degrees of protection are currently only achieved by intravenous, and not by intradermal or subcutaneous injection of viable parasites. It is known that only a small proportion of subcutaneously administered parasites reach the subsequent liver stage and low parasite liver load was shown to be associated with low protective efficacy. The objective of this analysis was to evaluate whether the liver load following subcutaneous parasite injection could be augmented by co-administration of pro-inflammatory or anti-coagulatory drugs. METHODS In the C57BL/6 Plasmodium berghei ANKA model, the clinical outcome (time to patent blood stage infection and survival) and relative parasite liver load was assessed in mice infected by subcutaneous or intramuscular sporozoite (SPZ) administration in the presence or absence of histamine and heparin supplementation in comparison to intravenously administered SPZ. In addition, a vaccination experiment was carried out to assess the protective efficacy of an improved, histamine-supplemented subcutaneous immunization regimen. RESULTS The parasite liver load following subcutaneous SPZ administration can be significantly increased by co-administration of histamine and heparin. A dose-dependent relation between parasite liver load and histamine dosage was observed. However, despite a relatively high parasite liver load, the protective efficacy of histamine-supplemented subcutaneous immunization remains inferior as compared to intravenous SPZ administration. CONCLUSIONS Histamine supplementation might facilitate the future development of a non-intravenous whole-parasite vaccine. Further investigations are needed to reveal the effect of histamine supplementation and subcutaneous SPZ administration on the acquisition of protective immunity.
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113
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Salman AM, Mogollon CM, Lin JW, van Pul FJA, Janse CJ, Khan SM. Generation of Transgenic Rodent Malaria Parasites Expressing Human Malaria Parasite Proteins. Methods Mol Biol 2015; 1325:257-286. [PMID: 26450395 DOI: 10.1007/978-1-4939-2815-6_21] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We describe methods for the rapid generation of transgenic rodent Plasmodium berghei (Pb) parasites that express human malaria parasite (HMP) proteins, using the recently developed GIMO-based transfection methodology. Three different genetic modifications are described resulting in three types of transgenic parasites. (1) Additional Gene (AG) mutants. In these mutants the HMP gene is introduced as an "additional gene" into a silent/neutral locus of the Pb genome under the control of either a constitutive or stage-specific Pb promoter. This method uses the GIMO-transfection protocol and AG mutants are generated by replacing the positive-negative selection marker (SM) hdhfr::yfcu cassette in a neutral locus of a standard GIMO mother line with the HMP gene expression cassette, resulting in SM free transgenic parasites. (2) Double-step Replacement (DsR) mutants. In these mutants the coding sequence (CDS) of the Pb gene is replaced with the CDS of the HMP ortholog in a two-step GIMO-transfection procedure. This process involves first the replacement of the Pb CDS with the hdhfr::yfcu SM, followed by insertion of the HMP ortholog at the same locus thereby replacing hdhfr::yfcu with the HMP CDS. These steps use the GIMO-transfection protocol, which exploits both positive selection for Pb orthologous gene-deletion and negative selection for HMP gene-insertion, resulting in SM free transgenic parasites. (3) Double-step Insertion (DsI) mutants. When a Pb gene is essential for blood stage development the DsR strategy is not possible. In these mutants the HMP expression cassette is first introduced into the neutral locus in a standard GIMO mother line as described for AG mutants but under the control elements of the Pb orthologous gene; subsequently, the Pb ortholog CDS is targeted for deletion through replacement of the Pb CDS with the hdhfr::yfcu SM, resulting in transgenic parasites with a new GIMO locus permissive for additional gene-insertion modifications.The different types of transgenic parasites can be exploited to examine interactions of drugs/inhibitors or immune factors with HMP molecules in vivo. Mice either immunized with HMP-vaccines or treated with specific drugs can be infected/challenged with these transgenic mutants to evaluate drug or vaccine efficacy in vivo.
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Affiliation(s)
- Ahmed M Salman
- Leiden Malaria Research Group, Department of Parasitology, LUMC, Leiden, The Netherlands
- The Jenner Institute, University of Oxford, Oxford, UK
| | | | - Jing-Wen Lin
- Leiden Malaria Research Group, Department of Parasitology, LUMC, Leiden, The Netherlands
- Division of Parasitology, MRC National Institute for Medical Research, London, UK
| | - Fiona J A van Pul
- Leiden Malaria Research Group, Department of Parasitology, LUMC, Leiden, The Netherlands
| | - Chris J Janse
- Leiden Malaria Research Group, Department of Parasitology, LUMC, Leiden, The Netherlands
| | - Shahid M Khan
- Leiden Malaria Research Group, Department of Parasitology, LUMC, Leiden, The Netherlands.
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114
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Sack BK, Miller JL, Vaughan AM, Kappe SHI. Measurement of Antibody-Mediated Reduction of Plasmodium yoelii Liver Burden by Bioluminescent Imaging. Methods Mol Biol 2015; 1325:69-80. [PMID: 26450380 PMCID: PMC8441651 DOI: 10.1007/978-1-4939-2815-6_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Antibodies against the infectious sporozoite stage of malaria have been shown to be effective in preventing infection of the liver and in mitigating the ensuing blood stage. However, only a handful of antibody targets have been vetted and shown to be successful in mediating in vivo protection. Even more limited are the means with which to measure how effectively antibodies can reduce the number of parasites establishing infection in the liver. Traditionally, only qPCR of infected mouse livers could accurately measure liver parasite burden. However, this procedure requires sacrifice of the animal and precludes monitoring of the ensuing blood stage infection. Herein we describe a method of accurately assessing antibody-mediated reduction of parasite liver burden by combining passive or active immunization of mice and mosquito bite challenge with luciferase-expressing transgenic P. yoelii parasites. This method is rapid, reliable and allows for observation of blood stage disease in the same animal. This model will prove integral in screening the efficacy of novel antibody targets as the search for a more effective malaria vaccine continues.
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Affiliation(s)
- Brandon K Sack
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109, USA.
| | - Jessica L Miller
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109, USA
| | - Ashley M Vaughan
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109, USA
| | - Stefan H I Kappe
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, WA, 98109, USA
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115
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Matsuoka H, Tomita H, Hattori R, Arai M, Hirai M. Visualization of Malaria Parasites in the Skin Using the Luciferase Transgenic Parasite, Plasmodium berghei. Trop Med Health 2014; 43:53-61. [PMID: 25859153 PMCID: PMC4361344 DOI: 10.2149/tmh.2014-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 11/13/2014] [Indexed: 01/25/2023] Open
Abstract
We produced a transgenic rodent malaria parasite (Plasmodium berghei) that contained the luciferase gene under a promoter region of elongation factor-1α. These transgenic (TG) parasites expressed luciferase in all stages of their life cycle, as previously reported. However, we were the first to succeed in observing sporozoites as a mass in mouse skin following their deposition by the probing of infective mosquitoes. Our transgenic parasites may have emitted stronger bioluminescence than previous TG parasites. The estimated number of injected sporozoites by mosquitoes was between 34 and 775 (median 80). Since luciferase activity diminished immediately after the death of the parasites, luciferase activity could be an indicator of the existence of live parasites. Our results indicated that sporozoites survived at the probed site for more than 42 hours. We also detected sporozoites in the liver within 15 min of the intravenous injection. Bioluminescence was not observed in the lung, kidney or spleen. We confirmed the observation that the liver was the first organ in which malaria parasites entered and increased in number.
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Affiliation(s)
- Hiroyuki Matsuoka
- Division of Medical Zoology, Jichi Medical University , 3311-1 Yakushiji, Shimotsuke-shi 329-0498, Japan
| | - Hiroyuki Tomita
- Division of Medical Zoology, Jichi Medical University , 3311-1 Yakushiji, Shimotsuke-shi 329-0498, Japan
| | - Ryuta Hattori
- Division of Medical Zoology, Jichi Medical University , 3311-1 Yakushiji, Shimotsuke-shi 329-0498, Japan
| | - Meiji Arai
- Division of Medical Zoology, Jichi Medical University , 3311-1 Yakushiji, Shimotsuke-shi 329-0498, Japan ; Department of International Medical Zoology, Graduate School of Medicine, Kagawa University , Miki-cho 761-0793, Japan
| | - Makoto Hirai
- Division of Medical Zoology, Jichi Medical University , 3311-1 Yakushiji, Shimotsuke-shi 329-0498, Japan ; Department of Parasitology, School of Medicine, Juntendo University , Bunkyo-ku, Tokyo 113-8421, Japan
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van Schaijk BCL, Ploemen IHJ, Annoura T, Vos MW, Foquet L, van Gemert GJ, Chevalley-Maurel S, van de Vegte-Bolmer M, Sajid M, Franetich JF, Lorthiois A, Leroux-Roels G, Meuleman P, Hermsen CC, Mazier D, Hoffman SL, Janse CJ, Khan SM, Sauerwein RW. A genetically attenuated malaria vaccine candidate based on P. falciparum b9/slarp gene-deficient sporozoites. eLife 2014; 3. [PMID: 25407681 PMCID: PMC4273440 DOI: 10.7554/elife.03582] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 11/19/2014] [Indexed: 12/16/2022] Open
Abstract
A highly efficacious pre-erythrocytic stage vaccine would be an important tool for the control and elimination of malaria but is currently unavailable. High-level protection in humans can be achieved by experimental immunization with Plasmodium falciparum sporozoites attenuated by radiation or under anti-malarial drug coverage. Immunization with genetically attenuated parasites (GAP) would be an attractive alternative approach. In this study, we present data on safety and protective efficacy using sporozoites with deletions of two genes, that is the newly identified b9 and slarp, which govern independent and critical processes for successful liver-stage development. In the rodent malaria model, PbΔb9ΔslarpGAP was completely attenuated showing no breakthrough infections while efficiently inducing high-level protection. The human PfΔb9ΔslarpGAP generated without drug resistance markers were infective to human hepatocytes in vitro and to humanized mice engrafted with human hepatocytes in vivo but completely aborted development after infection. These findings support the clinical development of a PfΔb9ΔslarpSPZ vaccine. DOI:http://dx.doi.org/10.7554/eLife.03582.001 Vaccines commonly contain a weakened or dead version of a disease-causing microorganism, or its toxins, or surface proteins. These prime the immune system to rapidly recognize, respond to, and eliminate the actual infectious pathogen if later encountered. While vaccines are currently available to help prevent a large number of diseases, vaccines for many deadly diseases, including malaria, do not yet exist. Malaria is caused by a group of parasites called Plasmodium, which are transferred to humans by mosquitoes. While measures to control mosquito populations and prevent mosquito bites have helped to reduce the incidence of malaria in some countries, the number of people—and especially children—that die of malaria every year remains very high. When a mosquito carrying Plasmodium in its salivary glands bites a human, the parasite is injected into the human's bloodstream and travels to the liver. The parasite reproduces in the liver cells until there are so many of them that the cells rupture, and the parasites are released back into the bloodstream. Any mosquito that then feeds on the blood of the infected individual may also suck up the parasite. The parasite then goes through a further stage of development in the mosquito, eventually migrating to the salivary glands, from where the parasite can be transmitted into a new human host. Recent work in rodents suggests that genetically altered or weakened Plasmodium falciparum sporozoites—the form of the parasite found in mosquito saliva—could be used to vaccinate humans against malaria caused by this parasite species. Now, van Schaijk, Ploemen et al. evaluate whether a safe and effective vaccine could be made from sporozoites that lack two genes, called b9 and slarp, which are critical for the parasites to develop inside liver cells. When mice were injected with the modified sporozoites, their immune cells were able to detect the parasites and respond against them. The mice subsequently did not develop malaria when they were infected with normal, unmodified parasites. Furthermore, none of the mice contracted malaria from the modified sporozoites. The modified sporozoites behaved similarly in human liver cells: after invading these cells, the parasites were unable to develop. Clinical testing and further development are now needed to see if a successful malaria vaccine can be made from these sporozoites. DOI:http://dx.doi.org/10.7554/eLife.03582.002
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Affiliation(s)
- Ben C L van Schaijk
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Ivo H J Ploemen
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Takeshi Annoura
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Martijn W Vos
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Lander Foquet
- Center for Vaccinology, Ghent University and University Hospital, Ghent, Belgium
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | | | - Marga van de Vegte-Bolmer
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Mohammed Sajid
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Jean-Francois Franetich
- Centre d'Immunologie et des Maladies Infectieuses, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Audrey Lorthiois
- Centre d'Immunologie et des Maladies Infectieuses, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Geert Leroux-Roels
- Center for Vaccinology, Ghent University and University Hospital, Ghent, Belgium
| | - Philip Meuleman
- Center for Vaccinology, Ghent University and University Hospital, Ghent, Belgium
| | - Cornelius C Hermsen
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Dominique Mazier
- Centre d'Immunologie et des Maladies Infectieuses, Université Pierre et Marie Curie-Paris 6, Paris, France
| | | | - Chris J Janse
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Shahid M Khan
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
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117
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Immunization of mice with live-attenuated late liver stage-arresting Plasmodium yoelii parasites generates protective antibody responses to preerythrocytic stages of malaria. Infect Immun 2014; 82:5143-53. [PMID: 25267837 DOI: 10.1128/iai.02320-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Understanding protective immunity to malaria is essential for the design of an effective vaccine to prevent the large number of infections and deaths caused by this parasitic disease. To date, whole-parasite immunization with attenuated parasites is the most effective method to confer sterile protection against malaria infection in clinical trials. Mouse model studies have highlighted the essential role that CD8(+) T cells play in protection against preerythrocytic stages of malaria; however, there is mounting evidence that antibodies are also important in these stages. Here, we show that experimental immunization of mice with Plasmodium yoelii fabb/f(-) (Pyfabb/f(-)), a genetically attenuated rodent malaria parasite that arrests late in the liver stage, induced functional antibodies that inhibited hepatocyte invasion in vitro and reduced liver-stage burden in vivo. These antibodies were sufficient to induce sterile protection from challenge by P. yoelii sporozoites in the absence of T cells in 50% of mice when sporozoites were administered by mosquito bite but not when they were administered by intravenous injection. Moreover, among mice challenged by mosquito bite, a higher proportion of BALB/c mice than C57BL/6 mice developed sterile protection (62.5% and 37.5%, respectively). Analysis of the antibody isotypes induced by immunization with Pyfabb/f(-) showed that, overall, BALB/c mice developed an IgG1-biased response, whereas C57BL/6 mice developed an IgG2b/c-biased response. Our data demonstrate for the first time that antibodies induced by experimental immunization of mice with a genetically attenuated rodent parasite play a protective role during the preerythrocytic stages of malaria. Furthermore, they highlight the importance of considering both the route of challenge and the genetic background of the mouse strains used when interpreting vaccine efficacy studies in animal models of malaria infection.
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118
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Pfeil J, Sepp KJ, Heiss K, Meister M, Mueller AK, Borrmann S. Protection against malaria by immunization with non-attenuated sporozoites under single-dose piperaquine-tetraphosphate chemoprophylaxis. Vaccine 2014; 32:6005-11. [PMID: 25203450 DOI: 10.1016/j.vaccine.2014.07.112] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 07/16/2014] [Accepted: 07/28/2014] [Indexed: 11/30/2022]
Abstract
Experimental whole-parasite immunization through concurrent administration of infectious Plasmodium sporozoites with drugs that prevent pathogenic blood-stage infection represents the current benchmark in malaria vaccine development. Key questions concerning translation remain, including the requirement for single-dose drug regimens that can reliably prevent breakthrough infections. We assessed the feasibility and efficacy of immunization with single-dose piperaquine chemoprophylaxis and concurrent sporozoite administration (PPQ-CPS) in the murine P. berghei ANKA/C57BL/6 infection model. We demonstrate that PPQ-CPS is protective with an efficacy comparable to previous findings using whole-parasite immunization under chloroquine chemoprophylaxis. PPQ-CPS immunization resulted in an expansion of intrahepatic and intrasplenic effector memory CD8(+) T cells. In summary, PPQ-CPS appears to be a safe and efficacious immunization regimen in the rodent malaria model and may thus become an important improvement regarding the translation of whole-parasite immunization toward a human malaria vaccine.
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Affiliation(s)
- Johannes Pfeil
- Department of Infectious Diseases, Parasitology Unit, University Hospital, Heidelberg, Germany; Center for Childhood and Adolescent Medicine, General Pediatrics, University Hospital, Heidelberg, Germany; German Center for Infection Research (DZIF), Heidelberg, Germany.
| | - Katharina Jutta Sepp
- Department of Infectious Diseases, Parasitology Unit, University Hospital, Heidelberg, Germany; German Center for Infection Research (DZIF), Heidelberg, Germany
| | - Kirsten Heiss
- Department of Infectious Diseases, Parasitology Unit, University Hospital, Heidelberg, Germany; MalVa GmbH, Heidelberg, Germany
| | - Michael Meister
- German Cancer Research Center (DKFZ), Department of Molecular Immunology (D050), Heidelberg, Germany
| | - Ann-Kristin Mueller
- Department of Infectious Diseases, Parasitology Unit, University Hospital, Heidelberg, Germany; German Center for Infection Research (DZIF), Heidelberg, Germany
| | - Steffen Borrmann
- German Center for Infection Research (DZIF), Tübingen, Germany; Institute for Tropical Medicine, University of Tübingen, Germany
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119
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Derbyshire ER, Zuzarte-Luís V, Magalhães AD, Kato N, Sanschagrin PC, Wang J, Zhou W, Miduturu CV, Mazitschek R, Sliz P, Mota MM, Gray NS, Clardy J. Chemical interrogation of the malaria kinome. Chembiochem 2014; 15:1920-30. [PMID: 25111632 DOI: 10.1002/cbic.201400025] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Indexed: 01/10/2023]
Abstract
Malaria, an infectious disease caused by eukaryotic parasites of the genus Plasmodium, afflicts hundreds of millions of people every year. Both the parasite and its host utilize protein kinases to regulate essential cellular processes. Bioinformatic analyses of parasite genomes predict at least 65 protein kinases, but their biological functions and therapeutic potential are largely unknown. We profiled 1358 small-molecule kinase inhibitors to evaluate the role of both the human and the malaria kinomes in Plasmodium infection of liver cells, the parasites' obligatory but transient developmental stage that precedes the symptomatic blood stage. The screen identified several small molecules that inhibit parasite load in liver cells, some with nanomolar efficacy, and each compound was subsequently assessed for activity against blood-stage malaria. Most of the screening hits inhibited both liver- and blood-stage malaria parasites, which have dissimilar gene expression profiles and infect different host cells. Evaluation of existing kinase activity profiling data for the library members suggests that several kinases are essential to malaria parasites, including cyclin-dependent kinases (CDKs), glycogen synthase kinases, and phosphoinositide-3-kinases. CDK inhibitors were found to bind to Plasmodium protein kinase 5, but it is likely that these compounds target multiple parasite kinases. The dual-stage inhibition of the identified kinase inhibitors makes them useful chemical probes and promising starting points for antimalarial development.
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Affiliation(s)
- Emily R Derbyshire
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 (USA).
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120
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Dual-stage triterpenoids from an African medicinal plant targeting the malaria parasite. Bioorg Med Chem 2014; 22:3887-90. [DOI: 10.1016/j.bmc.2014.06.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/06/2014] [Accepted: 06/07/2014] [Indexed: 11/18/2022]
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121
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Oliveira R, Guedes RC, Meireles P, Albuquerque IS, Gonçalves LM, Pires E, Bronze MR, Gut J, Rosenthal PJ, Prudêncio M, Moreira R, O’Neill PM, Lopes F. Tetraoxane–Pyrimidine Nitrile Hybrids as Dual Stage Antimalarials. J Med Chem 2014; 57:4916-23. [DOI: 10.1021/jm5004528] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Rudi Oliveira
- Instituto
de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Rita C. Guedes
- Instituto
de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Patrícia Meireles
- Instituto
de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Inês S. Albuquerque
- Instituto
de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Lídia M. Gonçalves
- Instituto
de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Elisabete Pires
- ITQB-UNL, Av. da República, Estação
Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Maria Rosário Bronze
- Instituto
de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
- ITQB-UNL, Av. da República, Estação
Agronómica Nacional, 2780-157 Oeiras, Portugal
| | - Jiri Gut
- Department
of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, California 94143, United States
| | - Philip J. Rosenthal
- Department
of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, California 94143, United States
| | - Miguel Prudêncio
- Instituto
de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Rui Moreira
- Instituto
de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Paul M. O’Neill
- Department
of Chemistry, University of Liverpool, Liverpool, L69 3BX, U.K
| | - Francisca Lopes
- Instituto
de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
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122
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Zuzarte-Luis V, Mota MM, Vigário AM. Malaria infections: what and how can mice teach us. J Immunol Methods 2014; 410:113-22. [PMID: 24837740 DOI: 10.1016/j.jim.2014.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/24/2014] [Accepted: 05/01/2014] [Indexed: 01/07/2023]
Abstract
Malaria imposes a horrific public health burden - hundreds of millions of infections and millions of deaths - on large parts of the world. While this unacceptable health burden and its economic and social impact have made it a focal point of the international development agenda, it became consensual that malaria control or elimination will be difficult to attain prior to gain a better understanding of the complex interactions occurring between its main players: Plasmodium, the causative agent of disease, and its hosts. Practical and ethical limitations exist regarding the ability to carry out research with human subjects or with human samples. In this review, we highlight how rodent models of infection have contributed significantly during the past decades to a better understanding of the basic biology of the parasite, host response and pathogenesis.
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Affiliation(s)
- Vanessa Zuzarte-Luis
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal.
| | - Ana M Vigário
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal; Unidade de Ciências Médicas, Centro de Competência de Ciências da Vida, Universidade da Madeira, Funchal, Portugal.
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123
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Manzoni G, Briquet S, Risco-Castillo V, Gaultier C, Topçu S, Ivănescu ML, Franetich JF, Hoareau-Coudert B, Mazier D, Silvie O. A rapid and robust selection procedure for generating drug-selectable marker-free recombinant malaria parasites. Sci Rep 2014; 4:4760. [PMID: 24755823 PMCID: PMC3996467 DOI: 10.1038/srep04760] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 04/04/2014] [Indexed: 12/22/2022] Open
Abstract
Experimental genetics have been widely used to explore the biology of the malaria parasites. The rodent parasites Plasmodium berghei and less frequently P. yoelii are commonly utilised, as their complete life cycle can be reproduced in the laboratory and because they are genetically tractable via homologous recombination. However, due to the limited number of drug-selectable markers, multiple modifications of the parasite genome are difficult to achieve and require large numbers of mice. Here we describe a novel strategy that combines positive-negative drug selection and flow cytometry-assisted sorting of fluorescent parasites for the rapid generation of drug-selectable marker-free P. berghei and P. yoelii mutant parasites expressing a GFP or a GFP-luciferase cassette, using minimal numbers of mice. We further illustrate how this new strategy facilitates phenotypic analysis of genetically modified parasites by fluorescence and bioluminescence imaging of P. berghei mutants arrested during liver stage development.
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Affiliation(s)
- Giulia Manzoni
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France [4]
| | - Sylvie Briquet
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France [4]
| | - Veronica Risco-Castillo
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France
| | - Charlotte Gaultier
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France [4]
| | - Selma Topçu
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France
| | - Maria Larisa Ivănescu
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France
| | - Jean-François Franetich
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France
| | - Bénédicte Hoareau-Coudert
- Sorbonne Universités, UPMC Univ Paris 06, Plateforme de Cytométrie en Flux CyPS, site Pitié-Salpêtrière, Paris, France
| | - Dominique Mazier
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France [4] Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires La Pitié Salpêtrière - Charles Foix, Service de Parasitologie-Mycologie, Paris, France
| | - Olivier Silvie
- 1] Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 75013, Paris, France [2] INSERM, U1135, CIMI-Paris, 75013, Paris, France [3] CNRS, ERL 8255, CIMI-Paris, 75013, Paris, France
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Li Q, O'Neil M, Xie L, Caridha D, Zeng Q, Zhang J, Pybus B, Hickman M, Melendez V. Assessment of the prophylactic activity and pharmacokinetic profile of oral tafenoquine compared to primaquine for inhibition of liver stage malaria infections. Malar J 2014; 13:141. [PMID: 24731238 PMCID: PMC3989846 DOI: 10.1186/1475-2875-13-141] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/02/2014] [Indexed: 11/10/2022] Open
Abstract
Background As anti-malarial drug resistance escalates, new safe and effective medications are necessary to prevent and treat malaria infections. The US Army is developing tafenoquine (TQ), an analogue of primaquine (PQ), which is expected to be more effective in preventing malaria in deployed military personnel. Methods To compare the prophylactic efficacy of TQ and PQ, a transgenic Plasmodium berghei parasite expressing the bioluminescent reporter protein luciferase was utilized to visualize and quantify parasite development in C57BL/6 albino mice treated with PQ and TQ in single or multiple regimens using a real-time in vivo imaging system (IVIS). As an additional endpoint, blood stage parasitaemia was monitored by flow cytometry. Comparative pharmacokinetic (PK) and liver distribution studies of oral and intravenous PQ and TQ were also performed. Results Mice treated orally with three doses of TQ at 5 mg/kg three doses of PQ at 25 mg/kg demonstrated no bioluminescence liver signal and no blood stage parasitaemia was observed suggesting both drugs showed 100% causal activity at the doses tested. Single dose oral treatment with 5 mg TQ or 25 mg of PQ, however, yielded different results as only TQ treatment resulted in causal prophylaxis in P. berghei sporozoite-infected mice. TQ is highly effective for causal prophylaxis in mice at a minimal curative single oral dose of 5 mg/kg, which is a five-fold improvement in potency versus PQ. PK studies of the two drugs administered orally to mice showed that the absolute bioavailability of oral TQ was 3.5-fold higher than PQ, and the AUC of oral TQ was 94-fold higher than oral PQ. The elimination half-life of oral TQ in mice was 28 times longer than PQ, and the liver tissue distribution of TQ revealed an AUC that was 188-fold higher than PQ. Conclusions The increased drug exposure levels and longer exposure time of oral TQ in the plasma and livers of mice highlight the lead quality attributes that explain the much improved efficacy of TQ when compared to PQ.
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Affiliation(s)
- Qigui Li
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA.
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125
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Paveley RA, Bickle QD. Automated imaging and other developments in whole-organism anthelmintic screening. Parasite Immunol 2014; 35:302-13. [PMID: 23581722 DOI: 10.1111/pim.12037] [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] [Received: 01/24/2013] [Accepted: 04/06/2013] [Indexed: 12/13/2022]
Abstract
Helminth infections still represent a huge public health problem throughout the developing world and in the absence of vaccines control is based on periodic mass drug administration. Poor efficacy of some anthelmintics and concerns about emergence of drug resistance has highlighted the need for new drug discovery. Most current anthelmintics were discovered through in vivo screening of selected compounds in animal models but recent approaches have shifted towards screening for activity against adult or larval stages in vitro. Larvae are normally available in greater numbers than adults, can often be produced in vitro and are small enough for microplate assays. However, the manual visualization of drug effects in vitro is subjective, laborious and slow. This can be overcome by application of automated readouts including high-content imaging. Incorporated into robotically controlled HTS platforms such methods allow the very large compound collections being made available by the pharmaceutical industry or academic organizations to be screened against helminths for the first time, invigorating the drug discovery pipeline. Here, we review the status of whole-organism screens based on in vitro activity against living worms and highlight the recent progress towards automated image-based readouts.
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Affiliation(s)
- R A Paveley
- Department of Infection and Immunity, London School of Hygiene and Tropical Medicine, London, UK
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126
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Miranda D, Capela R, Albuquerque IS, Meireles P, Paiva I, Nogueira F, Amewu R, Gut J, Rosenthal PJ, Oliveira R, Mota MM, Moreira R, Marti F, Prudêncio M, O’Neill PM, Lopes F. Novel endoperoxide-based transmission-blocking antimalarials with liver- and blood-schizontocidal activities. ACS Med Chem Lett 2014; 5:108-12. [PMID: 24900781 DOI: 10.1021/ml4002985] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 12/20/2013] [Indexed: 11/29/2022] Open
Abstract
In a search for effective compounds against both the blood- and liver-stages of infection by malaria parasites with the ability to block the transmission of the disease to mosquito vectors, a series of hybrid compounds combining either a 1,2,4-trioxane or 1,2,4,5-tetraoxane and 8-aminoquinoline moieties were synthesized and screened for their antimalarial activity. These hybrid compounds showed high potency against both exoerythrocytic and erythrocytic forms of malaria parasites, comparable to representative trioxane-based counterparts. Furthermore, they efficiently blocked the development of the sporogonic cycle in the mosquito vector. The tetraoxane-based hybrid 5, containing an amide linker between the two moieties, effectively cleared a patent blood-stage P. berghei infection in mice after i.p. administration. Overall, these results indicate that peroxide-8-aminoquinoline hybrids are excellent starting points to develop an agent that conveys all the desired antimalarial multistage activities in a single chemical entity and, as such, with the potential to be used in malaria elimination campaigns.
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Affiliation(s)
- Daniela Miranda
- Research
Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty
of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-019 Lisbon, Portugal
| | - Rita Capela
- Research
Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty
of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-019 Lisbon, Portugal
| | - Inês S. Albuquerque
- Instituto
de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Patrícia Meireles
- Instituto
de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Isa Paiva
- Centro
de Malária e Outras Doenças Tropicais, IHMT, Universidade Nova de Lisboa, Rua da Junqueira No. 100, P-1349-008 Lisbon, Portugal
| | - Fátima Nogueira
- Centro
de Malária e Outras Doenças Tropicais, IHMT, Universidade Nova de Lisboa, Rua da Junqueira No. 100, P-1349-008 Lisbon, Portugal
| | - Richard Amewu
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K
| | - Jiri Gut
- Department
of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, California 94143, United States
| | - Philip J. Rosenthal
- Department
of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, California 94143, United States
| | - Rudi Oliveira
- Research
Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty
of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-019 Lisbon, Portugal
| | - Maria M. Mota
- Instituto
de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Rui Moreira
- Research
Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty
of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-019 Lisbon, Portugal
| | - Francesc Marti
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K
| | - Miguel Prudêncio
- Instituto
de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Paul M. O’Neill
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K
| | - Francisca Lopes
- Research
Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty
of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-019 Lisbon, Portugal
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127
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Annoura T, van Schaijk BCL, Ploemen IHJ, Sajid M, Lin JW, Vos MW, Dinmohamed AG, Inaoka DK, Rijpma SR, van Gemert GJ, Chevalley-Maurel S, Kiełbasa SM, Scheltinga F, Franke-Fayard B, Klop O, Hermsen CC, Kita K, Gego A, Franetich JF, Mazier D, Hoffman SL, Janse CJ, Sauerwein RW, Khan SM. Two Plasmodium 6-Cys family-related proteins have distinct and critical roles in liver-stage development. FASEB J 2014; 28:2158-70. [PMID: 24509910 DOI: 10.1096/fj.13-241570] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The 10 Plasmodium 6-Cys proteins have critical roles throughout parasite development and are targets for antimalaria vaccination strategies. We analyzed the conserved 6-cysteine domain of this family and show that only the last 4 positionally conserved cysteine residues are diagnostic for this domain and identified 4 additional "6-Cys family-related" proteins. Two of these, sequestrin and B9, are critical to Plasmodium liver-stage development. RT-PCR and immunofluorescence assays show that B9 is translationally repressed in sporozoites and is expressed after hepatocyte invasion where it localizes to the parasite plasma membrane. Mutants lacking B9 expression in the rodent malaria parasites P. berghei and P. yoelii and the human parasite P. falciparum developmentally arrest in hepatocytes. P. berghei mutants arrest in the livers of BALB/c (100%) and C57BL6 mice (>99.9%), and in cultures of Huh7 human-hepatoma cell line. Similarly, P. falciparum mutants while fully infectious to primary human hepatocytes abort development 3 d after infection. This growth arrest is associated with a compromised parasitophorous vacuole membrane a phenotype similar to, but distinct from, mutants lacking the 6-Cys sporozoite proteins P52 and P36. Our results show that 6-Cys proteins have critical but distinct roles in establishment and maintenance of a parasitophorous vacuole and subsequent liver-stage development.
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Affiliation(s)
- Takeshi Annoura
- 3Leiden Malaria Research Group, Department of Parasitology, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands.
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128
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Experimental Models of Microvascular Immunopathology: The Example of Cerebral Malaria. JOURNAL OF NEUROINFECTIOUS DISEASES 2014; 5:134. [PMID: 26430675 PMCID: PMC4586166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Human cerebral malaria is a severe and often lethal complication of Plasmodium falciparum infection. Complex host and parasite interactions should the precise mechanisms involved in the onset of this neuropathology. Adhesion of parasitised red blood cells and host cells to endothelial cells lead to profound endothelial alterations that trigger immunopathological changes, varying degrees of brain oedema and can compromise cerebral blood flow, cause cranial nerve dysfunction and hypoxia. Study of the cerebral pathology in human patients is limited to clinical and genetic field studies in endemic areas, thus cerebral malaria (CM) research relies heavily on experimental models. The availability of malaria models allows study from the inoculation of Plasmodium to the onset of disease and permit invasive experiments. Here, we discuss some aspects of our current understanding of CM, the experimental models available and some important recent findings extrapolated from these models.
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Filtjens J, Foquet L, Taveirne S, Van Ammel E, Vanhees M, Van Acker A, Kerre T, Taghon T, Vandekerckhove B, Plum J, Van den Steen PE, Leclercq G. Contribution of the Ly49E natural killer receptor in the immune response to Plasmodium berghei infection and control of hepatic parasite development. PLoS One 2014; 9:e87463. [PMID: 24498110 PMCID: PMC3907506 DOI: 10.1371/journal.pone.0087463] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 12/28/2013] [Indexed: 12/12/2022] Open
Abstract
Natural killer (NK) cells have different roles in the host response against Plasmodium-induced malaria depending on the stage of infection. Liver NK cells have a protective role during the initial hepatic stage of infection by production of the TH1-type cytokines IFN-γ and TNF-α. In the subsequent erythrocytic stage of infection, NK cells also induce protection through Th1-type cytokines but, in addition, may also promote development of cerebral malaria via CXCR3-induction on CD8+ T cells resulting in migration of these cells to the brain. We have recently shown that the regulatory Ly49E NK receptor is expressed on liver NK cells in particular. The main objective of this study was therefore to examine the role of Ly49E expression in the immune response upon Plasmodium berghei ANKA infection, for which we compared wild type (WT) to Ly49E knockout (KO) mice. We show that the parasitemia was higher at the early stage, i.e. at days 6–7 of Plasmodium berghei ANKA infection in Ly49E KO mice, which correlated with lower induction of CD69, IFN-γ and TNF-α in DX5− liver NK cells at day 5 post-infection. At later stages, these differences faded. There was also no difference in the kinetics and the percentage of cerebral malaria development and in lymphocyte CXCR3 expression in WT versus Ly49E KO mice. Collectively, we show that the immune response against Plasmodium berghei ANKA infection is not drastically affected in Ly49E KO mice. Although NK cells play a crucial role in Plasmodium infection and Ly49E is highly expressed on liver NK cells, the Ly49E NK receptor only has a temporarily role in the immune control of this parasite.
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Affiliation(s)
- Jessica Filtjens
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Lander Foquet
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Sylvie Taveirne
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Els Van Ammel
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Mandy Vanhees
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Aline Van Acker
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Tessa Kerre
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Tom Taghon
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Bart Vandekerckhove
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Jean Plum
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Philippe E. Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium
| | - Georges Leclercq
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
- * E-mail:
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130
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Zuzarte-Luis V, Sales-Dias J, Mota MM. Simple, sensitive and quantitative bioluminescence assay for determination of malaria pre-patent period. Malar J 2014; 13:15. [PMID: 24400642 PMCID: PMC3893453 DOI: 10.1186/1475-2875-13-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 12/31/2013] [Indexed: 12/22/2022] Open
Abstract
Background The first phase of malaria infection occurs in the liver and is clinically silent. Inside hepatocytes each Plasmodium sporozoite replicate into thousands of erythrocyte-infectious merozoites that when released into the blood stream result in clinical symptoms of the disease. The time between sporozoite inoculation and the appearance of parasites in the blood is defined as the pre-patent period, which is classically analysed by time-consuming and labor-intensive techniques, such as microscopy and PCR. Methods Luciferase-expressing Plasmodium berghei parasites were used to measure pre-patent period of malaria infection in rodents using a bioluminescence assay that requires only one microliter of blood collected from the tail-vein. The accuracy and sensitivity of this new method was compared with conventional microscopy and PCR based techniques, and its capacity to measure the impact of anti-malarial interventions against the liver evaluated. Results The described method is very sensitive allowing the detection of parasites during the first cycles of blood stage replication. It accurately translates differences in liver load due to inoculation of different sporozoite doses as well as a result of treatment with different primaquine regimens. Conclusions A novel, simple, fast, and sensitive method to measure pre-patent period of malaria infection in rodents is described here. The sensitivity and accuracy of this new method is comparable to standard PCR and microscopy-based techniques, respectively.
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Affiliation(s)
| | | | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa 1649-028, Portugal.
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131
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Gomes A, Pérez B, Albuquerque I, Machado M, Prudêncio M, Nogueira F, Teixeira C, Gomes P. N-cinnamoylation of antimalarial classics: quinacrine analogues with decreased toxicity and dual-stage activity. ChemMedChem 2013; 9:305-10. [PMID: 24474655 DOI: 10.1002/cmdc.201300459] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Indexed: 11/07/2022]
Abstract
Plasmodium falciparum, the causative agent of the most lethal form of malaria, is becoming increasingly resistant to most available drugs. A convenient approach to combat parasite resistance is the development of analogues of classical antimalarial agents, appropriately modified in order to restore their relevance in antimalarial chemotherapy. Following this line of thought, the design, synthesis and in vitro evaluation of N-cinnamoylated quinacrine surrogates, 9-(N-cinnamoylaminobutyl)-amino-6-chloro-2-methoxyacridines, is reported. The compounds were found to be highly potent against both blood-stage P.falciparum, chloroquine-sensitive 3D7 (IC50 =17.0-39.0 nM) and chloroquine-resistant W2 and Dd2 strains (IC50 =3.2-41.2 and 27.1-131.0 nM, respectively), and liver-stage P.berghei (IC50 =1.6-4.9 μM) parasites. These findings bring new hope for the possible future "rise of a fallen angel" in antimalarial chemotherapy, with a potential resurgence of quinacrine-related compounds as dual-stage antimalarial leads.
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Affiliation(s)
- Ana Gomes
- Centro de Investigação em Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, R. do Campo Alegre, 4169-007 Porto (Portugal)
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132
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Dihydroquinazolinone inhibitors of proliferation of blood and liver stage malaria parasites. Antimicrob Agents Chemother 2013; 58:1516-22. [PMID: 24366746 DOI: 10.1128/aac.02148-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Drugs that target both the liver and blood stages of malaria will be needed to reduce the disease's substantial worldwide morbidity and mortality. Evaluation of a 259-member library of compounds that block proliferation of the blood stage of malaria revealed several scaffolds--dihydroquinazolinones, phenyldiazenylpyridines, piperazinyl methyl quinolones, and bis-benzimidazoles--with promising activity against the liver stage. Focused structure-activity studies on the dihydroquinazolinone scaffold revealed several molecules with excellent potency against both blood and liver stages. One promising early lead with dual activity is 2-(p-bromophenyl)-3-(2-(diethylamino)ethyl)-2,3-dihydroquinazolin-4(1H)-one with 50% effective concentrations (EC50s) of 0.46 μM and 0.34 μM against liver stage Plasmodium berghei ANKA and blood stage Plasmodium falciparum 3D7 parasites, respectively. Structure-activity relationships revealed that liver stage activity for this compound class requires a 3-dialkyl amino ethyl group and is abolished by substitution at the ortho-position of the phenyl moiety. These compounds have minimal toxicity to mammalian cells and are thus attractive compounds for further development.
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133
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KAI407, a potent non-8-aminoquinoline compound that kills Plasmodium cynomolgi early dormant liver stage parasites in vitro. Antimicrob Agents Chemother 2013; 58:1586-95. [PMID: 24366744 PMCID: PMC3957848 DOI: 10.1128/aac.01927-13] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Preventing relapses of Plasmodium vivax malaria through a radical cure depends on use of the 8-aminoquinoline primaquine, which is associated with safety and compliance issues. For future malaria eradication strategies, new, safer radical curative compounds that efficiently kill dormant liver stages (hypnozoites) will be essential. A new compound with potential radical cure activity was identified using a low-throughput assay of in vitro-cultured hypnozoite forms of Plasmodium cynomolgi (an excellent and accessible model for Plasmodium vivax). In this assay, primary rhesus hepatocytes are infected with P. cynomolgi sporozoites, and exoerythrocytic development is monitored in the presence of compounds. Liver stage cultures are fixed after 6 days and stained with anti-Hsp70 antibodies, and the relative proportions of small (hypnozoite) and large (schizont) forms relative to the untreated controls are determined. This assay was used to screen a series of 18 known antimalarials and 14 new non-8-aminoquinolines (preselected for blood and/or liver stage activity) in three-point 10-fold dilutions (0.1, 1, and 10 μM final concentrations). A novel compound, designated KAI407 showed an activity profile similar to that of primaquine (PQ), efficiently killing the earliest stages of the parasites that become either primary hepatic schizonts or hypnozoites (50% inhibitory concentration [IC50] for hypnozoites, KAI407, 0.69 μM, and PQ, 0.84 μM; for developing liver stages, KAI407, 0.64 μM, and PQ, 0.37 μM). When given as causal prophylaxis, a single oral dose of 100 mg/kg of body weight prevented blood stage parasitemia in mice. From these results, we conclude that KAI407 may represent a new compound class for P. vivax malaria prophylaxis and potentially a radical cure.
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134
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Liehl P, Zuzarte-Luís V, Chan J, Zillinger T, Baptista F, Carapau D, Konert M, Hanson KK, Carret C, Lassnig C, Müller M, Kalinke U, Saeed M, Chora AF, Golenbock DT, Strobl B, Prudêncio M, Coelho LP, Kappe SH, Superti-Furga G, Pichlmair A, Vigário AM, Rice CM, Fitzgerald KA, Barchet W, Mota MM. Host-cell sensors for Plasmodium activate innate immunity against liver-stage infection. Nat Med 2013; 20:47-53. [PMID: 24362933 DOI: 10.1038/nm.3424] [Citation(s) in RCA: 205] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/08/2013] [Indexed: 12/15/2022]
Abstract
Before they infect red blood cells and cause malaria, Plasmodium parasites undergo an obligate and clinically silent expansion phase in the liver that is supposedly undetected by the host. Here, we demonstrate the engagement of a type I interferon (IFN) response during Plasmodium replication in the liver. We identified Plasmodium RNA as a previously unrecognized pathogen-associated molecular pattern (PAMP) capable of activating a type I IFN response via the cytosolic pattern recognition receptor Mda5. This response, initiated by liver-resident cells through the adaptor molecule for cytosolic RNA sensors, Mavs, and the transcription factors Irf3 and Irf7, is propagated by hepatocytes in an interferon-α/β receptor-dependent manner. This signaling pathway is critical for immune cell-mediated host resistance to liver-stage Plasmodium infection, which we find can be primed with other PAMPs, including hepatitis C virus RNA. Together, our results show that the liver has sensor mechanisms for Plasmodium that mediate a functional antiparasite response driven by type I IFN.
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Affiliation(s)
- Peter Liehl
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Vanessa Zuzarte-Luís
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Jennie Chan
- 1] Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA. [2]
| | - Thomas Zillinger
- 1] Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital of Bonn, Bonn, Germany. [2]
| | - Fernanda Baptista
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Daniel Carapau
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Madlen Konert
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Kirsten K Hanson
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Céline Carret
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Caroline Lassnig
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Mathias Müller
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ulrich Kalinke
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover Medical School and Helmholtz Centre for Infection Research, Hannover, Germany
| | - Mohsan Saeed
- Laboratory of Virology and Infectious Diseases, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA
| | - Angelo Ferreira Chora
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Douglas T Golenbock
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Birgit Strobl
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Luis P Coelho
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Stefan H Kappe
- Seattle Biomedical Research Institute, Seattle, Washington, USA
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Andreas Pichlmair
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Ana M Vigário
- 1] Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal. [2] Unidade de Ciências Médicas, Centro de compentência de ciências da vida, Universidade da Madeira, Funchal, Portugal
| | - Charles M Rice
- Laboratory of Virology and Infectious Diseases, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA
| | - Katherine A Fitzgerald
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Winfried Barchet
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital of Bonn, Bonn, Germany
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
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Yamamoto DS, Yokomine T, Sumitani M, Yagi K, Matsuoka H, Yoshida S. Visualization and live imaging analysis of a mosquito saliva protein in host animal skin using a transgenic mosquito with a secreted luciferase reporter system. INSECT MOLECULAR BIOLOGY 2013; 22:685-693. [PMID: 24118655 DOI: 10.1111/imb.12055] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Mosquitoes inject saliva into a vertebrate host during blood feeding. The analysis of mosquito saliva in host skin is important for the elucidation of the inflammatory responses to mosquito bites, the development of antithrombotic drugs, and the transmission-blocking of vector-borne diseases. We produced transgenic Anopheles stephensi mosquitoes expressing the secretory luciferase protein (MetLuc) fused to a saliva protein (AAPP) in the salivary glands. The transgene product (AAPP-MetLuc) of transgenic mosquitoes exhibited both luciferase activity as a MetLuc and binding activity to collagen as an AAPP. The detection of luminescence in the skin of mice bitten by transgenic mosquitoes showed that AAPP-MetLuc was injected into the skin as a component of saliva via blood feeding. AAPP-MetLuc remained at the mosquito bite site in host skin with luciferase activity for at least 4 h after blood feeding. AAPP was also suspected of remaining at the site of injury caused by the mosquito bite and blocking platelet aggregation by binding to collagen. These results demonstrated the establishment of visualization and time-lapse analysis of mosquito saliva in living vertebrate host skin. This technique may facilitate the analysis of mosquito saliva after its injection into host skin, and the development of new drugs and disease control strategies.
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Affiliation(s)
- D S Yamamoto
- Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke, Japan
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136
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Foquet L, Hermsen CC, van Gemert GJ, Libbrecht L, Sauerwein R, Meuleman P, Leroux-Roels G. Molecular detection and quantification of Plasmodium falciparum-infected human hepatocytes in chimeric immune-deficient mice. Malar J 2013; 12:430. [PMID: 24267791 PMCID: PMC4222492 DOI: 10.1186/1475-2875-12-430] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/10/2013] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Chimeric mice with humanized livers represent a promising tool for infections with Plasmodium falciparum to evaluate novel methods for prevention and treatment of pre-erythrocytic stages. Adequate assessment of hepatic infections is generally compromised by the limited number of human hepatocytes infected by developing parasites. METHODS A qPCR-based method has been developed that sensitively and reliably detects P. falciparum liver stage infection of humanized mice and quantitatively expresses the results as the number of parasites per human hepatocyte. RESULTS This assay allows for detection of liver stage parasites after challenging humanized mice with infected mosquito bites or after intravenous injection with sporozoites. The sensitivity of the protocol, which comprises approximately 25% of the total chimeric liver, allows for the detection of a single infected hepatocyte in the analysed tissue. CONCLUSIONS This method allows for the detection and quantification of P. falciparum parasites in chimeric mice repopulated with human hepatocytes. It will be a useful tool when studying the in vivo therapeutic and/or prophylactic qualities of novel compounds, small molecules or antibodies directed against the liver stage of P. falciparum infections.
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Affiliation(s)
- Lander Foquet
- Center for Vaccinology, Ghent University and University Hospital, De Pintelaan 185, Ghent 9000, Belgium.
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137
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Zou X, House BL, Zyzak MD, Richie TL, Gerbasi VR. Towards an optimized inhibition of liver stage development assay (ILSDA) for Plasmodium falciparum. Malar J 2013; 12:394. [PMID: 24191920 PMCID: PMC3831258 DOI: 10.1186/1475-2875-12-394] [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: 08/27/2013] [Accepted: 10/30/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Experimental vaccines targeting Plasmodium falciparum have had some success in recent years. These vaccines use attenuated parasites, recombinant sporozoite proteins, or DNA and virus combinations to induce cell-mediated immune responses and/or antibodies targeting sporozoite surface proteins. To capitalize on the success of these vaccines and understand the mechanisms by which these vaccines function, it is important to develop assays that measure correlates of protection in volunteers. The inhibition of liver stage development assay (ILSDA) tests antibodies for the ability to block sporozoite development in hepatocytes. As such the ILSDA is an excellent candidate assay to identify correlates of humoral protection, particularly against the liver stage of malaria infection. In addition, the ILSDA can be used as a tool to evaluate novel sporozoite antigens for future vaccine development. Historically the ILSDA has suffered from low sporozoite infection rates, absence of standardized reagents, and the subjectivity associated with the traditional primary outcome measures, which depend on microscopy of stained hepatocyte cultures. This study worked to significantly improve sporozoite infection rates in hepatocytes, modify key steps in the assay protocol to reduce experimental variability, and demonstrate the utility of the ILSDA in testing antibodies targeting the circumsporozoite protein. METHODS Cryopreserved primary human hepatocytes, Plasmodium falciparum sporozoites, and circumsporozoite antibodies were used to optimize the ILSDA. RESULTS Inoculation of cryopreserved primary human hepatocytes with Plasmodium falciparum sporozoites improved liver stage development in the ILSDA compared to HCO4 cells. In the ILSDA, circumsporozoite antibodies suppressed liver stage development in cryopreserved primary human hepatocytes in a concentration-dependent manner. Antibody-mediated suppression of parasite development in the ILSDA at a 96-hour endpoint was more robust than the 24-hour endpoint. CONCLUSIONS ILSDA performance is improved by the use of cryopreserved primary human hepatocytes, expediting interactions between sporozoites and hepatocytes, and extending the assay endpoint.
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Affiliation(s)
| | | | | | | | - Vincent R Gerbasi
- US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, Maryland, USA.
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138
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Spavieri J, Allmendinger A, Kaiser M, Itoe MA, Blunden G, Mota MM, Tasdemir D. Assessment of dual life stage antiplasmodial activity of british seaweeds. Mar Drugs 2013; 11:4019-34. [PMID: 24152562 PMCID: PMC3826147 DOI: 10.3390/md11104019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 10/08/2013] [Accepted: 10/11/2013] [Indexed: 01/29/2023] Open
Abstract
Terrestrial plants have proven to be a prolific producer of clinically effective antimalarial drugs, but the antimalarial potential of seaweeds has been little explored. The main aim of this study was to assess the in vitro chemotherapeutical and prophylactic potential of the extracts of twenty-three seaweeds collected from the south coast of England against blood stage (BS) and liver stage (LS) Plasmodium parasites. The majority (14) of the extracts were active against BS of P. falciparum, with brown seaweeds Cystoseira tamariscifolia, C. baccata and the green seaweed Ulva lactuca being the most active (IC(50)s around 3 μg/mL). The extracts generally had high selectivity indices (>10). Eight seaweed extracts inhibited the growth of LS parasites of P. berghei without any obvious effect on the viability of the human hepatoma (Huh7) cells, and the highest potential was exerted by U. lactuca and red seaweeds Ceramium virgatum and Halopitys incurvus (IC50 values 14.9 to 28.8 μg/mL). The LS-active extracts inhibited one or more key enzymes of the malarial type-II fatty acid biosynthesis (FAS-II) pathway, a drug target specific for LS. Except for the red seaweed Halopitys incurvus, all LS-active extracts showed dual activity versus both malarial intracellular stage parasites. This is the first report of LS antiplasmodial activity and dual stage inhibitory potential of seaweeds.
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Affiliation(s)
- Jasmine Spavieri
- Department of Pharmaceutical and Biological Chemistry, School of Pharmacy, University of London, London WC1N 1AX, UK; E-Mails: (J.S.); (A.A.)
| | - Andrea Allmendinger
- Department of Pharmaceutical and Biological Chemistry, School of Pharmacy, University of London, London WC1N 1AX, UK; E-Mails: (J.S.); (A.A.)
| | - Marcel Kaiser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel CH-4002, Switzerland; E-Mail:
- University of Basel, Petersplatz 1, Basel CH-4003, Switzerland
| | - Maurice Ayamba Itoe
- Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon 1649-028, Portugal; E-Mails: (M.A.I.); (M.M.M.)
| | - Gerald Blunden
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, UK; E-Mail:
| | - Maria M. Mota
- Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon 1649-028, Portugal; E-Mails: (M.A.I.); (M.M.M.)
| | - Deniz Tasdemir
- Department of Pharmaceutical and Biological Chemistry, School of Pharmacy, University of London, London WC1N 1AX, UK; E-Mails: (J.S.); (A.A.)
- School of Chemistry, National University of Ireland, Galway, Ireland
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139
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Highly sensitive quantitative real-time PCR for the detection of Plasmodium liver-stage parasite burden following low-dose sporozoite challenge. PLoS One 2013; 8:e77811. [PMID: 24098596 PMCID: PMC3788780 DOI: 10.1371/journal.pone.0077811] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 09/05/2013] [Indexed: 11/19/2022] Open
Abstract
The pre-erythrocytic stages of Plasmodiumspp. are increasingly recognised as ideal targets for prophylactic vaccines and drug treatments. Intense research efforts in the last decade have been focused on in vitro culture and in vivo detection and quantification of liver stage parasites to assess the effects of candidate vaccines or drugs. Typically, the onset of blood stage parasitaemia is used as a surrogate endpoint to estimate the efficacy of vaccines and drugs targeting pre-erythrocytic parasite stages in animal models. However, this provides no information on the parasite burden in the liver after vaccination or treatment and therefore does not detect partial efficacy of any vaccine or drug candidates. Herein, we describe a quantitative RT-PCR method adapted to detect and quantitate Plasmodium yoelii liver stages in mice with increased sensitivity even after challenge with as few as 50 cryopreserved sporozoites (corresponding to approximately 5-10 freshly isolated sporozoites). We have validated our quantitative RT-PCR assay according to the MIQE (Minimum Information for Publication of Quantitative Real-Time PCR Experiments) guidelines and established high reproducibility and accuracy. Our assay provides a rapid and reproducible assessment of liver stage parasite burden in rodent malaria models, thereby facilitating the evaluation of the efficacy of anti-malarial drugs or prophylactic vaccines with high precision and efficacy.
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140
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Ressurreição AS, Gonçalves D, Sitoe AR, Albuquerque IS, Gut J, Góis A, Gonçalves LM, Bronze MR, Hanscheid T, Biagini GA, Rosenthal PJ, Prudêncio M, O'Neill P, Mota MM, Lopes F, Moreira R. Structural optimization of quinolon-4(1H)-imines as dual-stage antimalarials: toward increased potency and metabolic stability. J Med Chem 2013; 56:7679-90. [PMID: 24020770 DOI: 10.1021/jm4011466] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Discovery of novel effective and safe antimalarials has been traditionally focused on targeting erythrocytic parasite stages that cause clinical symptoms. However, elimination of malaria parasites from the human population will be facilitated by intervention at different life-cycle stages of the parasite, including the obligatory developmental phase in the liver, which precedes the erythrocytic stage. We have previously reported that N-Mannich-based quinolon-4(1H)-imines are potent antiplasmodial agents but present several stability liabilities. We now report our efforts to optimize quinolon-4(1H)-imines as dual-stage antiplasmodial agents endowed with chemical and metabolic stability. We report compounds active against both the erythrocytic and exoerythrocytic forms of malaria parasites, such as the quinolon-4(1H)-imine 5p (IC50 values of 54 and 710 nM against the erythrocytic and exoerythrocytic forms), which constitute excellent starting points for further lead optimization as dual-stage antimalarials.
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Affiliation(s)
- Ana S Ressurreição
- Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon , Av. Prof. Gama Pinto, 1649-019 Lisbon, Portugal
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141
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Frevert U, Nacer A, Cabrera M, Movila A, Leberl M. Imaging Plasmodium immunobiology in the liver, brain, and lung. Parasitol Int 2013; 63:171-86. [PMID: 24076429 DOI: 10.1016/j.parint.2013.09.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 08/28/2013] [Accepted: 09/18/2013] [Indexed: 01/10/2023]
Abstract
Plasmodium falciparum malaria is responsible for the deaths of over half a million African children annually. Until a decade ago, dynamic analysis of the malaria parasite was limited to in vitro systems with the typical limitations associated with 2D monocultures or entirely artificial surfaces. Due to extremely low parasite densities, the liver was considered a black box in terms of Plasmodium sporozoite invasion, liver stage development, and merozoite release into the blood. Further, nothing was known about the behavior of blood stage parasites in organs such as the brain where clinical signs manifest and the ensuing immune response of the host that may ultimately result in a fatal outcome. The advent of fluorescent parasites, advances in imaging technology, and availability of an ever-increasing number of cellular and molecular probes have helped illuminate many steps along the pathogenetic cascade of this deadly tropical parasite.
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Affiliation(s)
- Ute Frevert
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine, 341 E 25 Street, New York, NY 10010, USA.
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142
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Rodrigues T, Ressurreição AS, da Cruz FP, Albuquerque IS, Gut J, Carrasco MP, Gonçalves D, Guedes RC, dos Santos DJVA, Mota MM, Rosenthal PJ, Moreira R, Prudêncio M, Lopes F. Flavones as isosteres of 4(1H)-quinolones: discovery of ligand efficient and dual stage antimalarial lead compounds. Eur J Med Chem 2013; 69:872-80. [PMID: 24125849 DOI: 10.1016/j.ejmech.2013.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 09/01/2013] [Accepted: 09/03/2013] [Indexed: 11/20/2022]
Abstract
Malaria is responsible for nearly one million deaths annually, and the increasing prevalence of multi-resistant strains of Plasmodium falciparum poses a great challenge to controlling the disease. A diverse set of flavones, isosteric to 4(1H)-quinolones, were prepared and profiled for their antiplasmodial activity against the blood stage of P. falciparum W2 strain, and the liver stage of the rodent parasite Plasmodium berghei. Ligand efficient leads were identified as dual stage antimalarials, suggesting that scaffold optimization may afford potent antiplasmodial compounds.
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Affiliation(s)
- Tiago Rodrigues
- Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-019 Lisbon, Portugal.
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143
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Flannery EL, Fidock DA, Winzeler EA. Using genetic methods to define the targets of compounds with antimalarial activity. J Med Chem 2013; 56:7761-71. [PMID: 23927658 DOI: 10.1021/jm400325j] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although phenotypic cellular screening has been used to drive antimalarial drug discovery in recent years, in some cases target-based drug discovery remains more attractive. This is especially true when appropriate high-throughput cellular assays are lacking, as is the case for drug discovery efforts that aim to provide a replacement for primaquine (4-N-(6-methoxyquinolin-8-yl)pentane-1,4-diamine), the only drug that can block Plasmodium transmission to Anopheles mosquitoes and eliminate liver-stage hypnozoites. At present, however, there are no known chemically validated parasite protein targets that are important in all Plasmodium parasite developmental stages and that can be used in traditional biochemical compound screens. We propose that a plethora of novel, chemically validated, cross-stage antimalarial targets still remain to be discovered from the ~5,500 proteins encoded by the Plasmodium genomes. Here we discuss how in vitro evolution of drug-resistant strains of Plasmodium falciparum and subsequent whole-genome analysis can be used to find the targets of some of the many compounds discovered in whole-cell phenotypic screens.
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Affiliation(s)
- Erika L Flannery
- Department of Pediatrics, University of California, San Diego, School of Medicine , 9500 Gilman Drive 0741, La Jolla, California 92093, United States
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144
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Ferrer M, Martin-Jaular L, De Niz M, Khan SM, Janse CJ, Calvo M, Heussler V, del Portillo HA. Imaging of the spleen in malaria. Parasitol Int 2013; 63:195-205. [PMID: 23999413 DOI: 10.1016/j.parint.2013.08.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 08/13/2013] [Accepted: 08/26/2013] [Indexed: 11/28/2022]
Abstract
Splenomegaly, albeit variably, is a hallmark of malaria; yet, the role of the spleen in Plasmodium infections remains vastly unknown. The implementation of imaging to study the spleen is rapidly advancing our knowledge of this so-called "blackbox" of the abdominal cavity. Not only has ex vivo imaging revealed the complex functional compartmentalization of the organ and immune effector cells, but it has also allowed the observation of major structural remodeling during infections. In vivo imaging, on the other hand, has allowed quantitative measurements of the dynamic passage of the parasite at spatial and temporal resolution. Here, we review imaging techniques used for studying the malarious spleen, from optical microscopy to in vivo imaging, and discuss the bright perspectives of evolving technologies in our present understanding of the role of this organ in infections caused by Plasmodium.
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Affiliation(s)
- Mireia Ferrer
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona) ISGlobal, Barcelona, Spain
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145
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Nganou-Makamdop K, Ploemen I, Behet M, Van Gemert GJ, Hermsen C, Roestenberg M, Sauerwein RW. Reduced Plasmodium berghei sporozoite liver load associates with low protective efficacy after intradermal immunization. Parasite Immunol 2013; 34:562-9. [PMID: 23171040 DOI: 10.1111/pim.12000.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Studies in animal models suggest that protection against malaria induced by intradermal (ID) administration of sporozoites is less effective compared to intravenous injection (IV). We investigated in a murine model the protective efficacy and immune responses after ID or IV immunization of sporozoites. Mice were immunized via either IV or ID route with Plasmodium berghei sporozoites in combination with chloroquine treatment (CPS) (allowing full liver stage development) or by γ-radiation-attenuated sporozoites (RAS) (early liver stage arrest). While IV immunization with both RAS and CPS generated 90-100% protection, ID immunization resulted in reduced levels of protection with either immunization strategy in both Balb/cByJ (50%) and C57BL/6j mice (7-13%). Lower protection by ID routing associated with a 30-fold lower parasite liver load [P < 0.001 (χ(2) = 49.08, d.f. = 1)] assessed by real-time in vivo imaging of bioluminescent P. berghei parasites. Unlike IV, ID immunization did not result in expansion of CD8+ T cells with effector memory phenotype and showed lower IFNγ responses irrespective of the immunization regime. In conclusion, protection against sporozoite infection is likely dependent on parasite liver infection and subsequently generated cellular immune responses.
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Affiliation(s)
- K Nganou-Makamdop
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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146
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Quantitative bioluminescent imaging of pre-erythrocytic malaria parasite infection using luciferase-expressing Plasmodium yoelii. PLoS One 2013; 8:e60820. [PMID: 23593316 PMCID: PMC3623966 DOI: 10.1371/journal.pone.0060820] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 03/03/2013] [Indexed: 11/30/2022] Open
Abstract
The liver stages of Plasmodium parasites are important targets for the development of anti-malarial vaccine candidates and chemoprophylaxis approaches that aim to prevent clinical infection. Analyzing the impact of interventions on liver stages in the murine malaria model system Plasmodium yoelii has been cumbersome and requires terminal procedures. In vivo imaging of bioluminescent parasites has previously been shown to be an effective and non-invasive alternative to monitoring liver stage burden in the Plasmodium berghei model. Here we report the generation and characterization of a transgenic P. yoelii parasite expressing the reporter protein luciferase throughout the parasite life cycle. In vivo bioluminescent imaging of these parasites allows for quantitative analysis of P. yoelii liver stage burden and parasite development, which is comparable to quantitative RT-PCR analysis of liver infection. Using this system, we show that both BALB/cJ and C57BL/6 mice show comparable susceptibility to P. yoelii infection with sporozoites and that bioluminescent imaging can be used to monitor protective efficacy of attenuated parasite immunizations. Thus, this rapid, simple and noninvasive method for monitoring P. yoelii infection in the liver provides an efficient system to screen and evaluate the effects of anti-malarial interventions in vivo and in real-time.
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147
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Dempsey E, Prudêncio M, Fennell BJ, Gomes-Santos CS, Barlow JW, Bell A. Antimitotic herbicides bind to an unidentified site on malarial parasite tubulin and block development of liver-stage Plasmodium parasites. Mol Biochem Parasitol 2013; 188:116-27. [PMID: 23523992 DOI: 10.1016/j.molbiopara.2013.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 03/07/2013] [Accepted: 03/14/2013] [Indexed: 02/04/2023]
Abstract
Malarial parasites are exquisitely susceptible to a number of microtubule inhibitors but most of these compounds also affect human microtubules. Herbicides of the dinitroaniline and phosphorothioamidate classes however affect some plant and protozoal cells but not mammalian ones. We have previously shown that these herbicides block schizogony in erythrocytic parasites of the most lethal human malaria, Plasmodium falciparum, disrupt their mitotic spindles, and bind selectively to parasite tubulin. Here we show for the first time that the antimitotic herbicides also block the development of malarial parasites in the liver stage. Structure-based design of novel antimalarial agents binding to tubulin at the herbicide site, which presumably exists on (some) parasite and plant tubulins but not mammalian ones, can therefore constitute an important transmission blocking approach. The nature of this binding site is controversial, with three overlapping but non-identical locations on α-tubulin proposed in the literature. We tested the validity of the three sites by (i) using site-directed mutagenesis to introduce six amino acid changes designed to occlude them, (ii) producing the resulting tubulins recombinantly in Escherichia coli and (iii) measuring the affinity of the herbicides amiprophosmethyl and oryzalin for these proteins in comparison with wild-type tubulins by fluorescence quenching. The changes had little or no effect, with dissociation constants (Kd) no more than 1.3-fold (amiprophosmethyl) or 1.6-fold (oryzalin) higher than wild-type. We conclude that the herbicides impair Plasmodium liver stage as well as blood stage development but that the location of their binding site on malarial parasite tubulin remains to be proven.
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Affiliation(s)
- Enda Dempsey
- Department of Microbiology, School of Genetics & Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
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148
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Nilsen A, LaCrue AN, White KL, Forquer IP, Cross RM, Marfurt J, Mather MW, Delves MJ, Shackleford DM, Saenz FE, Morrisey JM, Steuten J, Mutka T, Li Y, Wirjanata G, Ryan E, Duffy S, Kelly JX, Sebayang BF, Zeeman AM, Noviyanti R, Sinden RE, Kocken CHM, Price RN, Avery VM, Angulo-Barturen I, Jiménez-Díaz MB, Ferrer S, Herreros E, Sanz LM, Gamo FJ, Bathurst I, Burrows JN, Siegl P, Guy RK, Winter RW, Vaidya AB, Charman SA, Kyle DE, Manetsch R, Riscoe MK. Quinolone-3-diarylethers: a new class of antimalarial drug. Sci Transl Med 2013; 5:177ra37. [PMID: 23515079 PMCID: PMC4227885 DOI: 10.1126/scitranslmed.3005029] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The goal for developing new antimalarial drugs is to find a molecule that can target multiple stages of the parasite's life cycle, thus impacting prevention, treatment, and transmission of the disease. The 4(1H)-quinolone-3-diarylethers are selective potent inhibitors of the parasite's mitochondrial cytochrome bc1 complex. These compounds are highly active against the human malaria parasites Plasmodium falciparum and Plasmodium vivax. They target both the liver and blood stages of the parasite as well as the forms that are crucial for disease transmission, that is, the gametocytes, the zygote, the ookinete, and the oocyst. Selected as a preclinical candidate, ELQ-300 has good oral bioavailability at efficacious doses in mice, is metabolically stable, and is highly active in blocking transmission in rodent models of malaria. Given its predicted low dose in patients and its predicted long half-life, ELQ-300 has potential as a new drug for the treatment, prevention, and, ultimately, eradication of human malaria.
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Affiliation(s)
- Aaron Nilsen
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Alexis N. LaCrue
- Department of Global Health, College of Public Health, 3720 Spectrum Blvd. (Ste 304), Tampa, FL 33612, USA
| | - Karen L. White
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Isaac P. Forquer
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Richard M. Cross
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620-5250, USA
| | - Jutta Marfurt
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Michael W. Mather
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Michael J. Delves
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - David M. Shackleford
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Fabian E. Saenz
- Department of Global Health, College of Public Health, 3720 Spectrum Blvd. (Ste 304), Tampa, FL 33612, USA
| | - Joanne M. Morrisey
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Jessica Steuten
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Tina Mutka
- Department of Global Health, College of Public Health, 3720 Spectrum Blvd. (Ste 304), Tampa, FL 33612, USA
| | - Yuexin Li
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Grennady Wirjanata
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Eileen Ryan
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Sandra Duffy
- Eskitis Institute for Cell & Molecular Therapies, Brisbane Innovation Park, Nathan campus, Griffith University, QLD 4111, Australia
| | - Jane Xu Kelly
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Boni F. Sebayang
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
| | - Anne-Marie Zeeman
- Department of Parasitology, Biomedical Primate Research Centre, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| | - Rintis Noviyanti
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
| | - Robert E. Sinden
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Clemens H. M. Kocken
- Department of Parasitology, Biomedical Primate Research Centre, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| | - Ric N. Price
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7LJ, UK
| | - Vicky M. Avery
- Eskitis Institute for Cell & Molecular Therapies, Brisbane Innovation Park, Nathan campus, Griffith University, QLD 4111, Australia
| | - Iñigo Angulo-Barturen
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - María Belén Jiménez-Díaz
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Santiago Ferrer
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Esperanza Herreros
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Laura M. Sanz
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Francisco-Javier Gamo
- GlaxoSmithKline, Medicines Development Campus, Diseases of the Developing World, Severo Ochoa 2, Tres Cantos 28760, Madrid, Spain
| | - Ian Bathurst
- Medicines for Malaria Venture, 20, route de Pré-Bois, PO Box 1826, 1215 Geneva 15, Switzerland
| | - Jeremy N. Burrows
- Medicines for Malaria Venture, 20, route de Pré-Bois, PO Box 1826, 1215 Geneva 15, Switzerland
| | - Peter Siegl
- Siegl Pharma Consulting LLC, Blue Bell, PA, USA
| | - R. Kiplin Guy
- Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105-3678 USA
| | - Rolf W. Winter
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
| | - Akhil B. Vaidya
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Susan A. Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Dennis E. Kyle
- Department of Global Health, College of Public Health, 3720 Spectrum Blvd. (Ste 304), Tampa, FL 33612, USA
| | - Roman Manetsch
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620-5250, USA
| | - Michael K. Riscoe
- VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, Oregon 97239, USA
- Department of Molecular Microbiology and Immunology, 3181 Sam Jackson Blvd., Portland, Oregon 97239, USA
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149
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Lin JW, Meireles P, Prudêncio M, Engelmann S, Annoura T, Sajid M, Chevalley-Maurel S, Ramesar J, Nahar C, Avramut CMC, Koster AJ, Matuschewski K, Waters AP, Janse CJ, Mair GR, Khan SM. Loss-of-function analyses defines vital and redundant functions of the Plasmodium rhomboid protease family. Mol Microbiol 2013; 88:318-38. [PMID: 23490234 DOI: 10.1111/mmi.12187] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2013] [Indexed: 11/26/2022]
Abstract
Rhomboid-like proteases cleave membrane-anchored proteins within their transmembrane domains. In apicomplexan parasites substrates include molecules that function in parasite motility and host cell invasion. While two Plasmodium rhomboids, ROM1 and ROM4, have been examined, the roles of the remaining six rhomboids during the malaria parasite's life cycle are unknown. We present systematic gene deletion analyses of all eight Plasmodium rhomboid-like proteins as a means to discover stage-specific phenotypes and potential functions in the rodent malaria model, P. berghei. Four rhomboids (ROM4, 6, 7 and 8) are refractory to gene deletion, suggesting an essential role during asexual blood stage development. In contrast ROM1, 3, 9 and 10 were dispensable for blood stage development and exhibited no, subtle or severe defects in mosquito or liver development. Parasites lacking ROM9 and ROM10 showed no major phenotypic defects. Parasites lacking ROM1 presented a delay in blood stage patency following liver infection, but in contrast to a previous study blood stage parasites had similar growth and virulence characteristics as wild type parasites. Parasites lacking ROM3 in mosquitoes readily established oocysts but failed to produce sporozoites. ROM3 is the first apicomplexan rhomboid identified to play a vital role in sporogony.
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Affiliation(s)
- Jing-Wen Lin
- Leiden Malaria Research Group (Parasitology), Leiden University Medical Centre, Leiden, The Netherlands
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150
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Reimão JQ, Trinconi CT, Yokoyama-Yasunaka JK, Miguel DC, Kalil SP, Uliana SRB. Parasite burden in Leishmania (Leishmania) amazonensis-infected mice: validation of luciferase as a quantitative tool. J Microbiol Methods 2013; 93:95-101. [PMID: 23466934 DOI: 10.1016/j.mimet.2013.02.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 02/22/2013] [Accepted: 02/23/2013] [Indexed: 10/27/2022]
Abstract
Given the lack of effective and safe alternatives to the drugs already in use, considerable efforts are being applied to the search of new therapeutic options to treat leishmaniasis. A necessary step in the discovery of antileishmanial drugs is the validation of drug candidates in mouse models. The standard methods to quantify the parasite burden in animal models, mainly culture-based, are time consuming and expensive. In recent years, in vivo imaging systems have been proposed as a tool to overcome these problems, allowing parasite detection in living organisms. Here we compared different treatment efficacy evaluation approaches. Recombinant Leishmania (L.) amazonensis lines expressing the luciferase gene (La-LUC) were obtained and characterized for biological properties as compared with the wild type (WT) parental line. Bioluminescence generated by La-LUC was shown to correlate with the number of promastigotes in vitro. La-LUC promastigotes and intracellular amastigotes were equally sensitive to amphotericin B (AmB) as the WT parasites. The clinical pattern of lesion development upon infection with the transgenic lines was similar to lesions observed after infection with the WT strain. The half maximal effective dose (ED50) of AmB was determined in La-LUC infected mice through quantification of bioluminescence in vivo and ex vivo, by limiting dilution and using clinical parameters. There was agreement in the ED50 determined by all methods. Quantification of bioluminescence in vivo and/or ex vivo was elected as the best tool for determining parasite burden to assess drug efficacy in infected mice. Furthermore, the detailed analysis of AmB effectiveness in this model generated useful data to be used in drug combination experiments.
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Affiliation(s)
- Juliana Q Reimão
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, 05508-000 São Paulo, Brazil.
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