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N'Guessan R, Camara S, Rowland M, Ahoua Alou LP, Wolie RZ, Zoh MG, N'Guessan B, Tia IZ, Oumbouke WA, Thomas MB, Koffi AA. Attractive targeted sugar bait: the pyrrole insecticide chlorfenapyr and the anti-malarial pharmaceutical artemether-lumefantrine arrest Plasmodium falciparum development inside wild pyrethroid-resistant Anopheles gambiae s.s. mosquitoes. Malar J 2023; 22:344. [PMID: 37946208 PMCID: PMC10636997 DOI: 10.1186/s12936-023-04758-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 10/18/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND Attractive targeted sugar bait (ATSB) is a novel approach to vector control, offering an alternative mode of insecticide delivery via the insect alimentary canal, with potential to deliver a variety of compounds new to medical entomology and malaria control. Its potential to control mosquitoes was recently demonstrated in major field trials in Africa. The pyrrole chlorfenapyr is an insecticide new to malaria vector control, and through its unique mode of action-disruption of ATP mediated energy transfer in mitochondria-it may have direct action on energy transfer in the flight muscle cells of mosquitoes. It may also have potential to disrupt mitochondrial function in malarial parasites co-existing within the infected mosquito. However, little is known about the impact of such compounds on vector competence in mosquitoes responsible for malaria transmission. METHODS In this study, ATSBs containing chlorfenapyr insecticide and, as a positive control, the anti-malarial drugs artemether/lumefantrine (A/L) were compared for their effect on Plasmodium falciparum development in wild pyrethroid-resistant Anopheles gambiae sensu stricto (s.s.) and for their capacity to reduce vector competence. Female mosquitoes were exposed to ATSB containing either sublethal dose of chlorfenapyr (CFP: 0.025%) or concentrations of A/L ranging from 0.4/2.4 mg/ml to 2.4/14.4 mg/ml, either shortly before or after taking infective blood meals. The impact of their component compounds on the prevalence and intensity of P. falciparum infection were compared between treatments. RESULTS Both the prevalence and intensity of infection were significantly reduced in mosquitoes exposed to either A/L or chlorfenapyr, compared to unexposed negative control mosquitoes. The A/L dose (2.4/14.4 mg/ml) totally erased P. falciparum parasites: 0% prevalence of infection in female mosquitoes exposed compared to 62% of infection in negative controls (df = 1, χ2 = 31.23 p < 0.001). The dose of chlorfenapyr (0.025%) that killed < 20% females in ATSB showed a reduction in oocyte density of 95% per midgut (0.18/3.43 per midgut). CONCLUSION These results are evidence that chlorfenapyr, in addition to its direct killing effect on the vector, has the capacity to block Plasmodium transmission by interfering with oocyte development inside pyrethroid-resistant mosquitoes, and through this dual action may potentiate its impact under field conditions.
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Affiliation(s)
- Raphael N'Guessan
- Institut Pierre Richet (IPR), Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire. Raphael.N'
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire. Raphael.N'
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK. Raphael.N'
| | - Soromane Camara
- Institut Pierre Richet (IPR), Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire.
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire.
| | - Mark Rowland
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Ludovic P Ahoua Alou
- Institut Pierre Richet (IPR), Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
| | - Rosine Z Wolie
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
- Université Nangui Abrogoua, UFR Des Sciences de la Nature, Abidjan, Côte d'Ivoire
| | - Marius G Zoh
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
| | - Brou N'Guessan
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
| | - Innocent Z Tia
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
| | - Welbeck A Oumbouke
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
- Innovative Vector Control Consortium, IVCC, Liverpool, UK
| | - Matthew B Thomas
- Department of Entomology & Nematology, The University of Florida, Gainesville, FL, USA
| | - Alphonsine A Koffi
- Institut Pierre Richet (IPR), Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
- Vector Control Product Evaluation Centre (VCPEC)-Institut Pierre Richet (VCPEC-IPR)/INSP, Bouaké, Côte d'Ivoire
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B Henry N, Soulama I, S Sermé S, Bolscher JM, T G Huijs T, S Coulibaly A, Sombié S, Ouédraogo N, Diarra A, Zongo S, Guelbéogo WM, Nébié I, Sirima SB, Tiono AB, Pietro A, Collins KA, Dechering KJ, Bousema T. Assessment of the transmission blocking activity of antimalarial compounds by membrane feeding assays using natural Plasmodium falciparum gametocyte isolates from West-Africa. PLoS One 2023; 18:e0284751. [PMID: 37494413 PMCID: PMC10370769 DOI: 10.1371/journal.pone.0284751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 04/07/2023] [Indexed: 07/28/2023] Open
Abstract
Antimalarial drugs that can block the transmission of Plasmodium gametocytes to mosquito vectors would be highly beneficial for malaria elimination efforts. Identifying transmission-blocking drugs currently relies on evaluation of their activity against gametocyte-producing laboratory parasite strains and would benefit from a testing pipeline with genetically diverse field isolates. The aims of this study were to develop a pipeline to test drugs against P. falciparum gametocyte field isolates and to evaluate the transmission-blocking activity of a set of novel compounds. Two assays were designed so they could identify both the overall transmission-blocking activity of a number of marketed and experimental drugs by direct membrane feeding assays (DMFA), and then also discriminate between those that are active against the gametocytes (gametocyte killing or sterilizing) or those that block development in the mosquito (sporontocidal). These DMFA assays used venous blood samples from naturally infected Plasmodium falciparum gametocyte carriers and locally reared Anopheles gambiae s.s. mosquitoes. Overall transmission-blocking activity was assessed following a 24 hour incubation of compound with gametocyte infected blood (TB-DMFA). Sporontocidal activity was evaluated following addition of compound directly prior to feeding, without incubation (SPORO-DMFA); Gametocyte viability was retained during 24-hour incubation at 37°C when gametocyte infected red blood cells were reconstituted in RPMI/serum. Methylene-blue, MMV693183, DDD107498, atovaquone and P218 showed potent transmission-blocking activity in the TB-DMFA, and both atovaquone and the novel antifolate P218 were potent inhibitors of sporogonic development in the SPORO-DMA. This work establishes a pipeline for the integral use of field isolates to assess the transmission-blocking capacity of antimalarial drugs to block transmission that should be validated in future studies.
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Affiliation(s)
- Noëlie B Henry
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issiaka Soulama
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
- Institut de Recherche en Sciences de la Santé (IRSS)/CNRST, Ouagadougou, Burkina Faso
| | - Samuel S Sermé
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | | | - Aboubacar S Coulibaly
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Salif Sombié
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Nicolas Ouédraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Amidou Diarra
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Soumanaba Zongo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Wamdaogo M Guelbéogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issa Nébié
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
| | | | - Alfred B Tiono
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Alano Pietro
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Roma, Italy
| | - Katharine A Collins
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherland
| | | | - Teun Bousema
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherland
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3
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Feng Y, Chen L, Gao L, Dong L, Wen H, Song X, Luo F, Cheng G, Wang J. Rapamycin inhibits pathogen transmission in mosquitoes by promoting immune activation. PLoS Pathog 2021; 17:e1009353. [PMID: 33626094 PMCID: PMC7939355 DOI: 10.1371/journal.ppat.1009353] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 03/08/2021] [Accepted: 02/02/2021] [Indexed: 11/18/2022] Open
Abstract
Repeated blood meals provide essential nutrients for mosquito egg development and routes for pathogen transmission. The target of rapamycin, the TOR pathway, is essential for vitellogenesis. However, its influence on pathogen transmission remains to be elucidated. Here, we show that rapamycin, an inhibitor of the TOR pathway, effectively suppresses Plasmodium berghei infection in Anopheles stephensi. An. stephensi injected with rapamycin or feeding on rapamycin-treated mice showed increased resistance to P. berghei infection. Exposing An. stephensi to a rapamycin-coated surface not only decreased the numbers of both oocysts and sporozoites but also impaired mosquito survival and fecundity. Transcriptome analysis revealed that the inhibitory effect of rapamycin on parasite infection was through the enhanced activation of immune responses, especially the NF-κB transcription factor REL2, a regulator of the immune pathway and complement system. Knockdown of REL2 in rapamycin-treated mosquitoes abrogated the induction of the complement-like proteins TEP1 and SPCLIP1 and abolished rapamycin-mediated refractoriness to Plasmodium infection. Together, these findings demonstrate a key role of the TOR pathway in regulating mosquito immune responses, thereby influencing vector competence. Anautogenous mosquitoes must consume vertebrate blood meals to complete oogenesis. Repeated blood feeding makes the mosquitoes efficient disease-transmitting vectors. The TOR pathway activated by ingested blood is known as an important regulator for vitellogenesis in mosquitoes. Herein, we show that the protein kinase TOR is involved in the regulation of mosquitoes’ susceptibility to Plasmodium infection. Inhibition of the TOR pathway by rapamycin upregulates the expression of REL2, a transcription factor controlling the expression of a variety of immune effectors. The enhanced immune responses in turn promote parasite elimination. Therefore, the TOR pathway plays a dual role in not only regulating mosquito reproduction but also in their vector potential.
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Affiliation(s)
- Yuebiao Feng
- The State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
| | - Lu Chen
- Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Medicine, Tsinghua University, Beijing, China
| | - Li Gao
- The State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
| | - Li Dong
- The State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
| | - Han Wen
- The State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
| | - Xiumei Song
- The State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
| | - Fang Luo
- The State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
| | - Gong Cheng
- Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Medicine, Tsinghua University, Beijing, China
- * E-mail: (GC); (JW)
| | - Jingwen Wang
- The State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
- * E-mail: (GC); (JW)
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4
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Burrows J, Fidock DA, Miller RS, Rees S. Blocking Plasmodium Development in Mosquitoes: A Powerful New Approach for Expanding Malaria Control Efforts. Am J Trop Med Hyg 2020; 101:734-735. [PMID: 31264564 PMCID: PMC6779223 DOI: 10.4269/ajtmh.19-0318] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
| | - David A Fidock
- Department of Microbiology and Immunology and Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | | | - Sarah Rees
- Innovative Vector Control Consortium, Liverpool, United Kingdom
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5
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Ethnobotanical Description and Biological Activities of Senna alata. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:2580259. [PMID: 32148534 PMCID: PMC7054808 DOI: 10.1155/2020/2580259] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/16/2020] [Accepted: 01/27/2020] [Indexed: 12/18/2022]
Abstract
Senna alata is a medicinal herb of Leguminosae family. It is distributed in the tropical and humid regions. The plant is traditionally used in the treatment of typhoid, diabetes, malaria, asthma, ringworms, tinea infections, scabies, blotch, herpes, and eczema. The review is aimed at unveiling the ethnobotanical description and pharmacological activities of S. alata. Different parts of the plant are reported in folk medicine as therapeutic substances for remediation of diverse diseases and infections. The extracts and isolated compounds displayed pronounced pharmacological activities. Display of antibacterial, antioxidant, antifungal, dermatophytic, anticancer, hepatoprotective, antilipogenic, anticonvulsant, antidiabetic, antihyperlipidemic, antimalarial, anthelmintic, and antiviral activities could be due to the array of secondary metabolites such as tannins, alkaloids, flavonoids, terpenes, anthraquinone, saponins, phenolics, cannabinoid alkaloids, 1,8-cineole, caryophyllene, limonene, α-selinene, β-caryophyllene, germacrene D, cinnamic acid, pyrazol-5-ol, methaqualone, isoquinoline, quinones, reducing sugars, steroids, and volatile oils present in different parts of the plant. The review divulges the ethnobotanical and pharmacological activities of the plant and also justifies the ethnomedical claims. The significant medicinal value of this plant necessitates a scientific adventure into the bioactive metabolites which constitute various extracts.
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Exposing Anopheles mosquitoes to antimalarials blocks Plasmodium parasite transmission. Nature 2019; 567:239-243. [PMID: 30814727 PMCID: PMC6438179 DOI: 10.1038/s41586-019-0973-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/29/2019] [Indexed: 02/03/2023]
Abstract
Every year the bites of Anopheles mosquitoes kill
hundreds of thousands of people, mostly young African children, by transmitting
deadly Plasmodium falciparum malaria parasites. Since the turn
of the century, efforts to prevent transmission of these parasites via the mass
distribution of insecticide-treated bed nets have been extremely successful,
causing an unprecedented reduction in malaria deaths1. However, resistance to insecticides has
become widespread in Anopheles populations2–4, threatening a global resurgence of the disease and making
the generation of effective new malaria control tools an urgent public health
priority. Here, we show that development of P. falciparum can
be rapidly and completely blocked when Anopheles gambiae
females uptake low concentrations of specific antimalarials from treated
surfaces, simulating contact with a bed net. Mosquito exposure to atovaquone
prior to or shortly after P. falciparum infection causes full
parasite arrest in the female midgut, preventing transmission of infection.
Similar transmission-blocking effects are achieved with other cytochrome B
inhibitors, demonstrating that parasite mitochondrial function is a good target
for parasite killing. Incorporating these effects into a model of malaria
transmission dynamics predicts that the inclusion of Plasmodium
inhibitors on mosquito nets would significantly mitigate the global health
impact of insecticide resistance. This study identifies a powerful new strategy
for blocking Plasmodium transmission by
Anopheles females, with promising implications for malaria
eradication efforts.
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7
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Is the Mitochondrion a Good Malaria Drug Target? Trends Parasitol 2017; 33:185-193. [DOI: 10.1016/j.pt.2016.10.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/25/2016] [Accepted: 10/06/2016] [Indexed: 01/21/2023]
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Reader J, Botha M, Theron A, Lauterbach SB, Rossouw C, Engelbrecht D, Wepener M, Smit A, Leroy D, Mancama D, Coetzer TL, Birkholtz LM. Nowhere to hide: interrogating different metabolic parameters of Plasmodium falciparum gametocytes in a transmission blocking drug discovery pipeline towards malaria elimination. Malar J 2015; 14:213. [PMID: 25994518 PMCID: PMC4449569 DOI: 10.1186/s12936-015-0718-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/22/2015] [Indexed: 12/23/2022] Open
Abstract
Background The discovery of malaria transmission-blocking compounds is seen as key to malaria elimination strategies and gametocyte-screening platforms are critical filters to identify active molecules. However, unlike asexual parasite assays measuring parasite proliferation, greater variability in end-point readout exists between different gametocytocidal assays. This is compounded by difficulties in routinely producing viable, functional and stage-specific gametocyte populations. Here, a parallel evaluation of four assay platforms on the same gametocyte populations was performed for the first time. This allowed the direct comparison of the ability of different assay platforms to detect compounds with gametocytocidal activity and revealed caveats in some assay readouts that interrogate different parasite biological functions. Methods Gametocytogenesis from Plasmodium falciparum (NF54) was optimized with a robust and standardized protocol. ATP, pLDH, luciferase reporter and PrestoBlue® assays were compared in context of a set of 10 reference compounds. The assays were performed in parallel on the same gametocyte preparation (except for luciferase reporter lines) using the same drug preparations (48 h). The remaining parameters for each assay were all comparable. Results A highly robust method for generating viable and functional gametocytes was developed and comprehensively validated resulting in an average gametocytaemia of 4 %. Subsequent parallel assays for gametocytocidal activity indicated that different assay platforms were not able to screen compounds with variant chemical scaffolds similarly. Luciferase reporter assays revealed that synchronized stage-specific gametocyte production is essential for drug discovery, as differential susceptibility in various gametocyte developmental populations is evident. Conclusions With this study, the key parameters for assays aiming at testing the gametocytocidal activity of potential transmission blocking molecules against Plasmodium gametocytes were accurately dissected. This first and uniquely comparative study emphasizes differential effects seen with the use of different assay platforms interrogating variant biological systems. Whilst this data is informative from a biological perspective and may provide indications of the drug mode of action, it does highlight the care that must be taken when screening broad-diversity chemotypes with a single assay platform against gametocytes for which the biology is not clearly understood. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0718-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Janette Reader
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Mariëtte Botha
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Anjo Theron
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, South Africa.
| | - Sonja B Lauterbach
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, 2193, South Africa.
| | - Claire Rossouw
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, South Africa.
| | - Dewaldt Engelbrecht
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, 2193, South Africa.
| | - Melanie Wepener
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, 2193, South Africa.
| | - Annél Smit
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland.
| | - Dalu Mancama
- Biosciences, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, South Africa.
| | - Theresa L Coetzer
- Plasmodium Molecular Research Unit, Wits Research Institute for Malaria, Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, 2193, South Africa.
| | - Lyn-Marie Birkholtz
- Malaria Parasite Molecular Laboratory, Centre for Sustainable Malaria Control, Department of Biochemistry, University of Pretoria, Private Bag x20, Hatfield, Pretoria, 0028, South Africa.
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Ke H, Lewis IA, Morrisey JM, McLean KJ, Ganesan SM, Painter HJ, Mather MW, Jacobs-Lorena M, Llinás M, Vaidya AB. Genetic investigation of tricarboxylic acid metabolism during the Plasmodium falciparum life cycle. Cell Rep 2015; 11:164-74. [PMID: 25843709 DOI: 10.1016/j.celrep.2015.03.011] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 02/11/2015] [Accepted: 03/04/2015] [Indexed: 12/24/2022] Open
Abstract
New antimalarial drugs are urgently needed to control drug-resistant forms of the malaria parasite Plasmodium falciparum. Mitochondrial electron transport is the target of both existing and new antimalarials. Herein, we describe 11 genetic knockout (KO) lines that delete six of the eight mitochondrial tricarboxylic acid (TCA) cycle enzymes. Although all TCA KOs grew normally in asexual blood stages, these metabolic deficiencies halted life-cycle progression in later stages. Specifically, aconitase KO parasites arrested as late gametocytes, whereas α-ketoglutarate-dehydrogenase-deficient parasites failed to develop oocysts in the mosquitoes. Mass spectrometry analysis of (13)C-isotope-labeled TCA mutant parasites showed that P. falciparum has significant flexibility in TCA metabolism. This flexibility manifested itself through changes in pathway fluxes and through altered exchange of substrates between cytosolic and mitochondrial pools. Our findings suggest that mitochondrial metabolic plasticity is essential for parasite development.
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Affiliation(s)
- Hangjun Ke
- Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Ian A Lewis
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Joanne M Morrisey
- Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Kyle J McLean
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD 21205, USA
| | - Suresh M Ganesan
- Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Heather J Painter
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Michael W Mather
- Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Marcelo Jacobs-Lorena
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD 21205, USA
| | - Manuel Llinás
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Akhil B Vaidya
- Center for Molecular Parasitology, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
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10
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Transmission-blocking interventions eliminate malaria from laboratory populations. Nat Commun 2013; 4:1812. [PMID: 23652000 PMCID: PMC3674233 DOI: 10.1038/ncomms2840] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 04/05/2013] [Indexed: 12/02/2022] Open
Abstract
Transmission-blocking interventions aim to reduce the prevalence of infection in endemic communities by targeting Plasmodium within the insect host. Although many studies have reported the successful reduction of infection in the mosquito vector, direct evidence that there is an onward reduction in infection in the vertebrate host is lacking. Here we report the first experiments using a population, transmission-based study of Plasmodium berghei in Anopheles stephensi to assess the impact of a transmission-blocking drug upon both insect and host populations over multiple transmission cycles. We demonstrate that the selected transmission-blocking intervention, which inhibits transmission from vertebrate to insect by only 32%, reduces the basic reproduction number of the parasite by 20%, and in our model system can eliminate Plasmodium from mosquito and mouse populations at low transmission intensities. These findings clearly demonstrate that use of transmission-blocking interventions alone can eliminate Plasmodium from a vertebrate population, and have significant implications for the future design and implementation of transmission-blocking interventions within the field. Transmission-blocking interventions aim to interrupt progression of Plasmodium parasites from the vertebrate host to the mosquito. Blagborough et al. demonstrate that only partially reducing transmission can be sufficient to eliminate experimental Plasmodium infection in successive mosquito and mice populations when biting rates are low.
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11
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Plasmodium cell biology should inform strategies used in the development of antimalarial transmission-blocking drugs. Future Med Chem 2013; 4:2251-63. [PMID: 23234549 DOI: 10.4155/fmc.12.182] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Malaria is a disease with a devastating impact affecting 216 million people each year and causing 655,000 deaths, most of which are children under 5 years old. Recent appreciation that malaria eradication will require novel interventions to target the parasite during transmission from the human host to the mosquito has lead to an exciting surge in activity to develop transmission-blocking drugs and the high-throughput assays to screen for them. This article presents an overview of transmission-stage cell biology and discusses its impact on assay development to provide a context for researchers to evaluate the relative merits/drawbacks of both screening data obtained from current assays and considerations for future assay design. The most recent knowledge of the transmission-blocking properties of current antimalarial classes is also summarized and, underdeveloped targets for transmission-stage drug discovery are highlighted.
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Delves M, Plouffe D, Scheurer C, Meister S, Wittlin S, Winzeler EA, Sinden RE, Leroy D. The activities of current antimalarial drugs on the life cycle stages of Plasmodium: a comparative study with human and rodent parasites. PLoS Med 2012; 9:e1001169. [PMID: 22363211 PMCID: PMC3283556 DOI: 10.1371/journal.pmed.1001169] [Citation(s) in RCA: 252] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 12/28/2011] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Malaria remains a disease of devastating global impact, killing more than 800,000 people every year-the vast majority being children under the age of 5. While effective therapies are available, if malaria is to be eradicated a broader range of small molecule therapeutics that are able to target the liver and the transmissible sexual stages are required. These new medicines are needed both to meet the challenge of malaria eradication and to circumvent resistance. METHODS AND FINDINGS Little is known about the wider stage-specific activities of current antimalarials that were primarily designed to alleviate symptoms of malaria in the blood stage. To overcome this critical gap, we developed assays to measure activity of antimalarials against all life stages of malaria parasites, using a diverse set of human and nonhuman parasite species, including male gamete production (exflagellation) in Plasmodium falciparum, ookinete development in P. berghei, oocyst development in P. berghei and P. falciparum, and the liver stage of P. yoelii. We then compared 50 current and experimental antimalarials in these assays. We show that endoperoxides such as OZ439, a stable synthetic molecule currently in clinical phase IIa trials, are strong inhibitors of gametocyte maturation/gamete formation and impact sporogony; lumefantrine impairs development in the vector; and NPC-1161B, a new 8-aminoquinoline, inhibits sporogony. CONCLUSIONS These data enable objective comparisons of the strengths and weaknesses of each chemical class at targeting each stage of the lifecycle. Noting that the activities of many compounds lie within achievable blood concentrations, these results offer an invaluable guide to decisions regarding which drugs to combine in the next-generation of antimalarial drugs. This study might reveal the potential of life-cycle-wide analyses of drugs for other pathogens with complex life cycles.
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Affiliation(s)
- Michael Delves
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - David Plouffe
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Christian Scheurer
- Swiss Tropical & Public Health Institute Swiss TPH, Basel, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Stephan Meister
- The Scripps Research Institute, La Jolla, California, United States of America
| | - Sergio Wittlin
- Swiss Tropical & Public Health Institute Swiss TPH, Basel, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Elizabeth A. Winzeler
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
- The Scripps Research Institute, La Jolla, California, United States of America
| | - Robert E. Sinden
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
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Korsinczky M, Chen N, Kotecka B, Saul A, Rieckmann K, Cheng Q. Mutations in Plasmodium falciparum cytochrome b that are associated with atovaquone resistance are located at a putative drug-binding site. Antimicrob Agents Chemother 2000; 44:2100-8. [PMID: 10898682 PMCID: PMC90020 DOI: 10.1128/aac.44.8.2100-2108.2000] [Citation(s) in RCA: 253] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atovaquone is the major active component of the new antimalarial drug Malarone. Considerable evidence suggests that malaria parasites become resistant to atovaquone quickly if atovaquone is used as a sole agent. The mechanism by which the parasite develops resistance to atovaquone is not yet fully understood. Atovaquone has been shown to inhibit the cytochrome bc(1) (CYT bc(1)) complex of the electron transport chain of malaria parasites. Here we report point mutations in Plasmodium falciparum CYT b that are associated with atovaquone resistance. Single or double amino acid mutations were detected from parasites that originated from a cloned line and survived various concentrations of atovaquone in vitro. A single amino acid mutation was detected in parasites isolated from a recrudescent patient following atovaquone treatment. These mutations are associated with a 25- to 9,354-fold range reduction in parasite susceptibility to atovaquone. Molecular modeling showed that amino acid mutations associated with atovaquone resistance are clustered around a putative atovaquone-binding site. Mutations in these positions are consistent with a reduced binding affinity of atovaquone for malaria parasite CYT b.
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Affiliation(s)
- M Korsinczky
- Parasitology and Arbovirology Department, Australian Army Malaria Institute, University of Queensland, St. Lucia, Australia
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Enosse S, Butcher GA, Margos G, Mendoza J, Sinden RE, Høgh B. The mosquito transmission of malaria: the effects of atovaquone-proguanil (Malarone) and chloroquine. Trans R Soc Trop Med Hyg 2000; 94:77-82. [PMID: 10748906 DOI: 10.1016/s0035-9203(00)90447-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Despite its recognized importance, the prevention of patients with malaria from continuing to infect mosquitoes after treatment is not always achieved in practice. An inevitable consequence of the prolonged life-span and relative metabolic stasis of the mature gametocytes of Plasmodium falciparum is that they are not cleared by most antimalarials, and few antimalarials block infection in the mosquito vector. Previous research on the constituents of Malarone, a new 'combined antimalarial', suggested that the active components, atovaquone and proguanil, might inhibit infectivity of gametocytes to mosquitoes. We contrast here the impact of atovaquone-proguanil and chloroquine on the transmission of P. falciparum and P. berghei. While chloroquine enhanced infectivity of P. falciparum, atovaquone-proguanil caused a significant reduction. Surprisingly, sporontocidal activity against the rodent parasite persisted long after the levels of the constituent drugs would have been expected to have fallen below effective plasma concentrations on the basis of the established pharmacokinetics of atovaquone and proguanil. The P. berghei model may thus have provided a sensitive bioassay, detecting drug(s) at levels below that normally found with the usual chemical assays.
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Affiliation(s)
- S Enosse
- Department of Blood Parasitology, National Institute of Health, Maputo, Mozambique
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Abstract
Mosquitoes of the genus Anopheles transmit malaria parasites to humans. Anopheles mosquito species vary in their vector potential because of environmental conditions and factors affecting their abundance, blood-feeding behavior, survival, and ability to support malaria parasite development. In the complex life cycle of the parasite in female mosquitoes, a process termed sporogony, mosquitoes acquire gametocyte-stage parasites from blood-feeding on an infected host. The parasites carry out fertilization in the midgut, transform to ookinetes, then oocysts, which produce sporozoites. Sporozoites invade the salivary glands and are transmitted when the mosquito feeds on another host. Most individual mosquitoes that ingest gametocytes do not support development to the sporozoite stage. Bottle-necks occur at every stage of the cycle in the mosquito. Powerful new techniques and approaches exist for evaluating malaria parasite development and for identifying mechanisms regulating malaria parasite-vector interactions. This review focuses on those interactions that are important for the development of new approaches for evaluating and blocking transmission in nature.
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Affiliation(s)
- J C Beier
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112, USA.
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Abstract
It is well-known that whenever possible, the treatment of patients with malaria should include measures to prevent them transmitting the infection to others. This is particularly important for P. falciparum, where the gametocytes can survive for a much longer period than the asexual stages. Not all antimalarials are gametocytocidal or sporontocidal and those that are may have particular disadvantages or lose their effectiveness because of resistance. Even drugs that have no obvious gametocytocidal or sporontocidal activity may have other effects. These include the possibility of increasing transmission, either by affecting the parasite within an individual host or by selection for parasite strains with increased potential for infecting the mosquito vector. This review summarises the available information on the properties of antimalarials in relation to mosquito transmission and highlights the need for more attention to be paid to this aspect of drug action.
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Affiliation(s)
- G A Butcher
- Department of Biology, Imperial College of Science, Technology and Medicine, London, U.K.
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Abstract
The purpose of this review is to summarize the biology of Plasmodium in the mosquito including recent data to contribute to better understanding of the developmental interaction between mosquito and malarial parasite. The entire sporogonic cycle is discussed taking into consideration different parasite/vector interactions and factors affecting parasite development to the mosquito.
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Affiliation(s)
- A B Simonetti
- Departamento de Microbiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brasil.
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Fleck SL, Pudney M, Sinden RE. The effect of atovaquone (566C80) on the maturation and viability of Plasmodium falciparum gametocytes in vitro. Trans R Soc Trop Med Hyg 1996; 90:309-12. [PMID: 8758088 DOI: 10.1016/s0035-9203(96)90266-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Atovaquone (566C80), a hydroxynaphthoquinone, was investigated for activity against Plasmodium falciparum gametocytes (NF54 strain) in vitro. After 96 h of continuous exposure to the drug at 1.4 x 10(-7) M (a concentration achievable in humans 14 d after administration of a therapeutic dose of 10 mg/kg) reductions of 75%, 54% and 20% in the number of gametocyte stages 2, 3 and 4, respectively, were achieved. A small increase (14%) in stage 5 gametocytes was seen. At the same concentration, atovaquone showed greater activity against the asexual stages of P. falciparum, reductions of 93%, 96% and 43% in the number of rings, schizonts and trophozoites, respectively, being achieved. These data are consistent with inhibition of maturation of trophozoites. The observed effect on maturation of gametocytes is similarly consistent with blockade of gametocyte recruitment from merozoites produced by the preceding schizogony, or to stasis of intraerythrocytic sexual development before the formation of stage 2 gametocytes.
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Affiliation(s)
- S L Fleck
- Department of Biology, Imperial College, London, UK
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