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Appetecchia F, Fabbrizi E, Fiorentino F, Consalvi S, Biava M, Poce G, Rotili D. Transmission-Blocking Strategies for Malaria Eradication: Recent Advances in Small-Molecule Drug Development. Pharmaceuticals (Basel) 2024; 17:962. [PMID: 39065810 DOI: 10.3390/ph17070962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 07/11/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024] Open
Abstract
Malaria drug research and development efforts have resurged in the last decade following the decelerating rate of mortality and malaria cases in endemic regions. The inefficiency of malaria interventions is largely driven by the spreading resistance of the Plasmodium falciparum parasite to current drug regimens and that of the malaria vector, the Anopheles mosquito, to insecticides. In response to the new eradication agenda, drugs that act by breaking the malaria transmission cycle (transmission-blocking drugs), which has been recognized as an important and additional target for intervention, are being developed. These drugs take advantage of the susceptibility of Plasmodium during population bottlenecks before transmission (gametocytes) and in the mosquito vector (gametes, zygotes, ookinetes, oocysts, sporozoites). To date, compounds targeting stage V gametocytes predominate in the chemical library of transmission-blocking drugs, and some of them have entered clinical trials. The targeting of Plasmodium mosquito stages has recently renewed interest in the development of innovative malaria control tools, which hold promise for the application of compounds effective at these stages. In this review, we highlight the major achievements and provide an update on the research of transmission-blocking drugs, with a particular focus on their chemical scaffolds, antiplasmodial activity, and transmission-blocking potential.
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Affiliation(s)
- Federico Appetecchia
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Emanuele Fabbrizi
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Francesco Fiorentino
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Sara Consalvi
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Mariangela Biava
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Giovanna Poce
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Dante Rotili
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
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2
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Fraser M, Curtis B, Phillips P, Yates PA, Lam KS, Netzel O, van Dooren GG, Ingmundson A, Matuschewski K, McLeod MD, Maier AG. Harnessing cholesterol uptake of malaria parasites for therapeutic applications. EMBO Mol Med 2024; 16:1515-1532. [PMID: 38862600 PMCID: PMC11251039 DOI: 10.1038/s44321-024-00087-1] [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: 10/18/2023] [Revised: 05/14/2024] [Accepted: 05/24/2024] [Indexed: 06/13/2024] Open
Abstract
Parasites, such as the malaria parasite P. falciparum, are critically dependent on host nutrients. Interference with nutrient uptake can lead to parasite death and, therefore, serve as a successful treatment strategy. P. falciparum parasites cannot synthesise cholesterol, and instead source this lipid from the host. Here, we tested whether cholesterol uptake pathways could be 'hijacked' for optimal drug delivery to the intracellular parasite. We found that fluorescent cholesterol analogues were delivered from the extracellular environment to the intracellular parasite. We investigated the uptake and inhibitory effects of conjugate compounds, where proven antimalarial drugs (primaquine and artesunate) were attached to steroids that mimic the structure of cholesterol. These conjugated antimalarial drugs improved the inhibitory effects against multiple parasite lifecycle stages, multiple parasite species, and drug-resistant parasites, whilst also lowering the toxicity to human host cells. Steroids with introduced peroxides also displayed antimalarial activity. These results provide a proof-of-concept that cholesterol mimics can be developed as a drug delivery system against apicomplexan parasites with the potential to improve drug efficacy, increase therapeutic index, and defeat drug resistance.
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Affiliation(s)
- Merryn Fraser
- Research School of Biology, The Australian National University, Canberra, 2601, Australia
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, 10115, Germany
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, 02115, USA
| | - Blake Curtis
- Research School of Chemistry, The Australian National University, Canberra, 2601, Australia
- Metabolism of Microbial Pathogens, Robert Koch Institute, Berlin, 13353, Germany
| | - Patrick Phillips
- Research School of Biology, The Australian National University, Canberra, 2601, Australia
| | - Patrick A Yates
- Research School of Chemistry, The Australian National University, Canberra, 2601, Australia
| | - Kwong Sum Lam
- Research School of Biology, The Australian National University, Canberra, 2601, Australia
| | - Otto Netzel
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, 10115, Germany
| | - Giel G van Dooren
- Research School of Biology, The Australian National University, Canberra, 2601, Australia
| | - Alyssa Ingmundson
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, 10115, Germany
| | - Kai Matuschewski
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, 10115, Germany
| | - Malcolm D McLeod
- Research School of Chemistry, The Australian National University, Canberra, 2601, Australia.
| | - Alexander G Maier
- Research School of Biology, The Australian National University, Canberra, 2601, Australia.
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3
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Tellier A, Hodgins K, Stephan W, Stukenbrock E. Rapid evolutionary adaptation: Potential and constraints. Mol Ecol 2024; 33:e17350. [PMID: 38591817 DOI: 10.1111/mec.17350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 03/18/2024] [Accepted: 03/28/2024] [Indexed: 04/10/2024]
Affiliation(s)
- Aurélien Tellier
- Population Genetics, Department of Life Science Systems, Technical University of Munich, Freising, Germany
| | - Kathryn Hodgins
- School of Biological Sciences, Monash University, Clayton, Australia
| | - Wolfgang Stephan
- Natural History Museum Berlin and University of Munich, Munich, Germany
| | - Eva Stukenbrock
- Botanical Institute, Christian-Albrechts University, Max Planck Institute for Evolutionary Biology, Plön, Germany
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Huffman A, Zhang X, Lanka M, Zheng J, Masci AM, He Y. Ontological representation, modeling, and analysis of parasite vaccines. J Biomed Semantics 2024; 15:4. [PMID: 38664818 PMCID: PMC11044459 DOI: 10.1186/s13326-024-00307-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Pathogenic parasites are responsible for multiple diseases, such as malaria and Chagas disease, in humans and livestock. Traditionally, pathogenic parasites have been largely an evasive topic for vaccine design, with most successful vaccines only emerging recently. To aid vaccine design, the VIOLIN vaccine knowledgebase has collected vaccines from all sources to serve as a comprehensive vaccine knowledgebase. VIOLIN utilizes the Vaccine Ontology (VO) to standardize the modeling of vaccine data. VO did not model complex life cycles as seen in parasites. With the inclusion of successful parasite vaccines, an update in parasite vaccine modeling was needed. RESULTS VIOLIN was expanded to include 258 parasite vaccines against 23 protozoan species, and 607 new parasite vaccine-related terms were added to VO since 2022. The updated VO design for parasite vaccines accounts for parasite life stages and for transmission-blocking vaccines. A total of 356 terms from the Ontology of Parasite Lifecycle (OPL) were imported to VO to help represent the effect of different parasite life stages. A new VO class term, 'transmission-blocking vaccine,' was added to represent vaccines able to block infectious transmission, and one new VO object property, 'blocks transmission of pathogen via vaccine,' was added to link vaccine and pathogen in which the vaccine blocks the transmission of the pathogen. Additionally, our Gene Set Enrichment Analysis (GSEA) of 140 parasite antigens used in the parasitic vaccines identified enriched features. For example, significant patterns, such as signal, plasma membrane, and entry into host, were found in the antigens of the vaccines against two parasite species: Plasmodium falciparum and Toxoplasma gondii. The analysis found 18 out of the 140 parasite antigens involved with the malaria disease process. Moreover, a majority (15 out of 54) of P. falciparum parasite antigens are localized in the cell membrane. T. gondii antigens, in contrast, have a majority (19/24) of their proteins related to signaling pathways. The antigen-enriched patterns align with the life cycle stage patterns identified in our ontological parasite vaccine modeling. CONCLUSIONS The updated VO modeling and GSEA analysis capture the influence of the complex parasite life cycles and their associated antigens on vaccine development.
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Affiliation(s)
- Anthony Huffman
- Department of Computational Medicine and Bioinformatics, University of Michigan Medicine School, 48109, Ann Arbor, MI, USA
| | - Xumeng Zhang
- College of Literature, Science, and the Arts, University of Michigan, 48109, Ann Arbor, MI, USA
| | - Meghana Lanka
- College of Literature, Science, and the Arts, University of Michigan, 48109, Ann Arbor, MI, USA
| | - Jie Zheng
- Unit for Laboratory Animal Medicine, University of Michigan Medicine School, 48109, Ann Arbor, MI, USA
| | - Anna Maria Masci
- Department of Data Impact and Governance, MD Anderson Cancer Center University of Texas, TX, 77030, Houston, USA
| | - Yongqun He
- Department of Computational Medicine and Bioinformatics, University of Michigan Medicine School, 48109, Ann Arbor, MI, USA.
- Unit for Laboratory Animal Medicine, University of Michigan Medicine School, 48109, Ann Arbor, MI, USA.
- Department of Microbiology and Immunology, University of Michigan Medicine School, 48109, Ann Arbor, MI, USA.
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5
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Li J, Docile HJ, Fisher D, Pronyuk K, Zhao L. Current Status of Malaria Control and Elimination in Africa: Epidemiology, Diagnosis, Treatment, Progress and Challenges. J Epidemiol Glob Health 2024:10.1007/s44197-024-00228-2. [PMID: 38656731 DOI: 10.1007/s44197-024-00228-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Accepted: 04/10/2024] [Indexed: 04/26/2024] Open
Abstract
The African continent carries the greatest malaria burden in the world. Falciparum malaria especially has long been the leading cause of death in Africa. Climate, economic factors, geographical location, human intervention and unstable security are factors influencing malaria transmission. Due to repeated infections and early interventions, the proportion of clinically atypical malaria or asymptomatic plasmodium carriers has increased significantly, which easily lead to misdiagnosis and missed diagnosis. African countries have made certain progress in malaria control and elimination, including rapid diagnosis of malaria, promotion of mosquito nets and insecticides, intermittent prophylactic treatment in high-risk groups, artemisinin based combination therapies, and the development of vaccines. Between 2000 and 2022, there has been a 40% decrease in malaria incidence and a 60% reduction in mortality rate in the WHO African Region. However, many challenges are emerging in the fight against malaria in Africa, such as climate change, poverty, substandard health services and coverage, increased outdoor transmission and the emergence of new vectors, and the growing threat of resistance to antimalarial drugs and insecticides. Joint prevention and treatment, identifying molecular determinants of resistance, new drug development, expanding seasonal malaria chemo-prevention intervention population, and promoting the vaccination of RTS, S/AS01 and R21/Matrix-M may help to solve the dilemma. China's experience in eliminating malaria is conducive to Africa's malaria prevention and control, and China-Africa cooperation needs to be constantly deepened and advanced. Our review aims to help the global public develop a comprehensive understanding of malaria in Africa, thereby contributing to malaria control and elimination.
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Affiliation(s)
- Jiahuan Li
- Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Haragakiza Jean Docile
- Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - David Fisher
- Department of Medical Biosciences, Faculty of Natural Sciences, University of The Western Cape, Cape Town, South Africa
| | - Khrystyna Pronyuk
- Department of Infectious Diseases, O. Bogomolets National Medical University, Kyiv, Ukraine
| | - Lei Zhao
- Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
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Suh E, Stopard IJ, Lambert B, Waite JL, Dennington NL, Churcher TS, Thomas MB. Estimating the effects of temperature on transmission of the human malaria parasite, Plasmodium falciparum. Nat Commun 2024; 15:3230. [PMID: 38649361 PMCID: PMC11035611 DOI: 10.1038/s41467-024-47265-w] [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: 09/25/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024] Open
Abstract
Despite concern that climate change could increase the human risk to malaria in certain areas, the temperature dependency of malaria transmission is poorly characterized. Here, we use a mechanistic model fitted to experimental data to describe how Plasmodium falciparum infection of the African malaria vector, Anopheles gambiae, is modulated by temperature, including its influences on parasite establishment, conversion efficiency through parasite developmental stages, parasite development rate, and overall vector competence. We use these data, together with estimates of the survival of infected blood-fed mosquitoes, to explore the theoretical influence of temperature on transmission in four locations in Kenya, considering recent conditions and future climate change. Results provide insights into factors limiting transmission in cooler environments and indicate that increases in malaria transmission due to climate warming in areas like the Kenyan Highlands, might be less than previously predicted.
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Affiliation(s)
- Eunho Suh
- Center for Infectious Disease Dynamics, Department of Entomology, The Pennsylvania State University, University Park, PA, USA.
| | - Isaac J Stopard
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Faculty of Medicine, Imperial College London, London, UK
| | - Ben Lambert
- Department of Statistics, University of Oxford, Oxford, UK
| | - Jessica L Waite
- Center for Infectious Disease Dynamics, Department of Entomology, The Pennsylvania State University, University Park, PA, USA
- Research Development, University of Vermont, Burlington, VT, USA
| | - Nina L Dennington
- Center for Infectious Disease Dynamics, Department of Entomology, The Pennsylvania State University, University Park, PA, USA
| | - Thomas S Churcher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Faculty of Medicine, Imperial College London, London, UK
| | - Matthew B Thomas
- Center for Infectious Disease Dynamics, Department of Entomology, The Pennsylvania State University, University Park, PA, USA
- Department of Biology, University of York, York, UK
- Invasion Science Research Institute and Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
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Bukhari T, Gichuhi J, Mbare O, Ochwal VA, Fillinger U, Herren JK. Willingness to accept and participate in a Microsporidia MB-based mosquito release strategy: a community-based rapid assessment in western Kenya. Malar J 2024; 23:113. [PMID: 38643165 PMCID: PMC11031974 DOI: 10.1186/s12936-024-04941-y] [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: 01/31/2024] [Accepted: 04/10/2024] [Indexed: 04/22/2024] Open
Abstract
BACKGROUND Microsporidia MB, an endosymbiont naturally found in Anopheles mosquitoes inhibits transmission of Plasmodium and is a promising candidate for a transmission-blocking strategy that may involve mosquito release. A rapid assessment was carried out to develop insight into sociodemographic factors, public health concerns, and malaria awareness, management, and prevention practices with the willingness to accept and participate in Microsporidia MB-based transmission-blocking strategy to develop an informed stakeholder engagement process. METHODS The assessment consisted of a survey conducted in two communities in western Kenya that involved administering a questionnaire consisting of structured, semi-structured, and open questions to 8108 household heads. RESULTS There was an overall high level of willingness to accept (81%) and participate in the implementation of the strategy (96%). Although the willingness to accept was similar in both communities, Ombeyi community was more willing to participate (OR 22, 95% CI 13-36). Women were less willing to accept (OR 0.8, 95% CI 0.7-0.9) compared to men due to fear of increased mosquito bites near homes. Household heads with incomplete primary education were more willing to accept (OR 1.6, 95% CI 01.2-2.2) compared to those educated to primary level or higher. Perceiving malaria as a moderate or low public health issue was also associated with a lower willingness to accept and participate. Experience of > 3 malaria cases in the family over the last six months and knowledge that malaria is transmitted by only mosquito bites, increased the willingness to accept but reduced the willingness to participate. Awareness of malaria control methods based on mosquitoes that cannot transmit malaria increases the willingness to participate. CONCLUSION The study showed a high level of willingness to accept and participate in a Microsporidia MB-based strategy in the community, which is influenced by several factors such as community, disease risk perception, gender, education level, knowledge, and experience of malaria. Further research will need to focus on understanding the concerns of women, educated, and employed community members, and factors that contribute to the lower disease risk perception. This improved understanding will lead to the development of an effective communication strategy.
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Affiliation(s)
- Tullu Bukhari
- Human Health, International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya.
| | - Joseph Gichuhi
- Human Health, International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
| | - Oscar Mbare
- Human Health, International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
| | - Victoria A Ochwal
- Human Health, International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
| | - Ulrike Fillinger
- Human Health, International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
| | - Jeremy K Herren
- Human Health, International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
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8
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Greyling N, van der Watt M, Gwarinda H, van Heerden A, Greenhouse B, Leroy D, Niemand J, Birkholtz LM. Genetic complexity alters drug susceptibility of asexual and gametocyte stages of Plasmodium falciparum to antimalarial candidates. Antimicrob Agents Chemother 2024; 68:e0129123. [PMID: 38259087 PMCID: PMC10916389 DOI: 10.1128/aac.01291-23] [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: 10/13/2023] [Accepted: 12/06/2023] [Indexed: 01/24/2024] Open
Abstract
Malaria elimination requires interventions able to target both the asexual blood stage (ABS) parasites and transmissible gametocyte stages of Plasmodium falciparum. Lead antimalarial candidates are evaluated against clinical isolates to address key concerns regarding efficacy and to confirm that the current, circulating parasites from endemic regions lack resistance against these candidates. While this has largely been performed on ABS parasites, limited data are available on the transmission-blocking efficacy of compounds with multistage activity. Here, we evaluated the efficacy of lead antimalarial candidates against both ABS parasites and late-stage gametocytes side-by-side, against clinical P. falciparum isolates from southern Africa. We additionally correlated drug efficacy to the genetic diversity of the clinical isolates as determined with a panel of well-characterized, genome-spanning microsatellite markers. Our data indicate varying sensitivities of the isolates to key antimalarial candidates, both for ABS parasites and gametocyte stages. While ABS parasites were efficiently killed, irrespective of genetic complexity, antimalarial candidates lost some gametocytocidal efficacy when the gametocytes originated from genetically complex, multiple-clone infections. This suggests a fitness benefit to multiclone isolates to sustain transmission and reduce drug susceptibility. In conclusion, this is the first study to investigate the efficacy of antimalarial candidates on both ABS parasites and gametocytes from P. falciparum clinical isolates where the influence of parasite genetic complexity is highlighted, ultimately aiding the malaria elimination agenda.
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Affiliation(s)
- Nicola Greyling
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Mariëtte van der Watt
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Hazel Gwarinda
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Ashleigh van Heerden
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Bryan Greenhouse
- Department of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Jandeli Niemand
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
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9
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van Heerden A, Turon G, Duran-Frigola M, Pillay N, Birkholtz LM. Machine Learning Approaches Identify Chemical Features for Stage-Specific Antimalarial Compounds. ACS OMEGA 2023; 8:43813-43826. [PMID: 38027377 PMCID: PMC10666252 DOI: 10.1021/acsomega.3c05664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/18/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023]
Abstract
Efficacy data from diverse chemical libraries, screened against the various stages of the malaria parasite Plasmodium falciparum, including asexual blood stage (ABS) parasites and transmissible gametocytes, serve as a valuable reservoir of information on the chemical space of compounds that are either active (or not) against the parasite. We postulated that this data can be mined to define chemical features associated with the sole ABS activity and/or those that provide additional life cycle activity profiles like gametocytocidal activity. Additionally, this information could provide chemical features associated with inactive compounds, which could eliminate any future unnecessary screening of similar chemical analogs. Therefore, we aimed to use machine learning to identify the chemical space associated with stage-specific antimalarial activity. We collected data from various chemical libraries that were screened against the asexual (126 374 compounds) and sexual (gametocyte) stages of the parasite (93 941 compounds), calculated the compounds' molecular fingerprints, and trained machine learning models to recognize stage-specific active and inactive compounds. We were able to build several models that predict compound activity against ABS and dual activity against ABS and gametocytes, with Support Vector Machines (SVM) showing superior abilities with high recall (90 and 66%) and low false-positive predictions (15 and 1%). This allowed the identification of chemical features enriched in active and inactive populations, an important outcome that could be mined for essential chemical features to streamline hit-to-lead optimization strategies of antimalarial candidates. The predictive capabilities of the models held true in diverse chemical spaces, indicating that the ML models are therefore robust and can serve as a prioritization tool to drive and guide phenotypic screening and medicinal chemistry programs.
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Affiliation(s)
- Ashleigh van Heerden
- Department
of Biochemistry, Genetics and Microbiology, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Gemma Turon
- Ersilia
Open Source Initiative, 28 Belgrave Road, Cambridge CB1 3DE, U.K.
| | | | - Nelishia Pillay
- Department
of Computer Science, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Lyn-Marié Birkholtz
- Department
of Biochemistry, Genetics and Microbiology, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
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10
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Kina UY, Kamil M, Deveci G, Rafiqi AM, Matuschewski K, Aly ASI. A Candidate Bacterial-Type Amino Acid Decarboxylase Is Essential for Male Gamete Exflagellation and Mosquito Transmission of the Malaria Parasite. Infect Immun 2023; 91:e0016723. [PMID: 37260388 PMCID: PMC10353352 DOI: 10.1128/iai.00167-23] [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: 05/03/2023] [Accepted: 05/07/2023] [Indexed: 06/02/2023] Open
Abstract
A frequent side effect of chemotherapy against malaria parasite blood infections is a dramatic induction of the sexual blood stages, thereby enhancing the risk of future malaria transmissions. The polyamine biosynthesis pathway has been suggested as a candidate target for transmission-blocking anti-malarial drug development. Herein, we describe the role of a bacterial-type amino acid decarboxylase (AAD) in the life cycle of the malaria model parasite Plasmodium yoelii. Hallmarks of AAD include a conserved catalytic lysine residue and high-level homology to arginine/lysine/ornithine decarboxylases of pathogenic bacteria. By targeted gene deletion, we show that AAD plays an essential role in the exflagellation of microgametes, resulting in complete absence of sporozoites in the mosquito vector. These data highlight the central role of the biosysthesis of polyamines in the final steps of male gamete sexual development of the malaria parasite and, hence, onward transmission to mosquitoes.
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Affiliation(s)
- Umit Y. Kina
- Aly lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
- Department of Biotechnology, Institute of Health Sciences, Bezmialem Vakif University, Istanbul, Turkey
| | - Mohd Kamil
- Aly lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Gozde Deveci
- Aly lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
| | - Ab. Matteen Rafiqi
- Aly lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
| | - Kai Matuschewski
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany
| | - Ahmed S. I. Aly
- Aly lab, Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
- School of Science and Engineering, Al Akhawayn University, Ifrane, Morocco
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11
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Miyazaki Y, Vos MW, Geurten FJA, Bigeard P, Kroeze H, Yoshioka S, Arisawa M, Inaoka DK, Soulard V, Dechering KJ, Franke-Fayard B, Miyazaki S. A versatile Plasmodium falciparum reporter line expressing NanoLuc enables highly sensitive multi-stage drug assays. Commun Biol 2023; 6:713. [PMID: 37438491 DOI: 10.1038/s42003-023-05078-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 06/27/2023] [Indexed: 07/14/2023] Open
Abstract
Transgenic luciferase-expressing Plasmodium falciparum parasites have been widely used for the evaluation of anti-malarial compounds. Here, to screen for anti-malarial drugs effective against multiple stages of the parasite, we generate a P. falciparum reporter parasite that constitutively expresses NanoLuciferase (NanoLuc) throughout its whole life cycle. The NanoLuc-expressing P. falciparum reporter parasite shows a quantitative NanoLuc signal in the asexual blood, gametocyte, mosquito, and liver stages. We also establish assay systems to evaluate the anti-malarial activity of compounds at the asexual blood, gametocyte, and liver stages, and then determine the 50% inhibitory concentration (IC50) value of several anti-malarial compounds. Through the development of this robust high-throughput screening system, we identify an anti-malarial compound that kills the asexual blood stage parasites. Our study highlights the utility of the NanoLuc reporter line, which may advance anti-malarial drug development through the improved screening of compounds targeting the human malarial parasite at multiple stages.
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Affiliation(s)
- Yukiko Miyazaki
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan.
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.
| | - Martijn W Vos
- TropIQ Health Sciences, Transistorweg 5, 6534 AT, Nijmegen, The Netherlands
| | - Fiona J A Geurten
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Pierre Bigeard
- Sorbonne Université, Inserm, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, F-75013, Paris, France
| | - Hans Kroeze
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Shohei Yoshioka
- Graduate School of Pharmaceutical Sciences, Osaka University, 565-0871, Osaka, Japan
| | - Mitsuhiro Arisawa
- Graduate School of Pharmaceutical Sciences, Osaka University, 565-0871, Osaka, Japan
| | - Daniel Ken Inaoka
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, 852-8523, Japan
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Valerie Soulard
- Sorbonne Université, Inserm, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, F-75013, Paris, France
| | - Koen J Dechering
- TropIQ Health Sciences, Transistorweg 5, 6534 AT, Nijmegen, The Netherlands
| | - Blandine Franke-Fayard
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Shinya Miyazaki
- Department of Parasitology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
- Department of Cellular Architecture Studies, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 852-8523, Nagasaki, Japan.
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12
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Bezerra JJL, Pinheiro AAV, Dourado D. Antimalarial potential of Moringa oleifera Lam. (Moringaceae): A review of the ethnomedicinal, pharmacological, toxicological, and phytochemical evidence. J Venom Anim Toxins Incl Trop Dis 2023; 29:e20220079. [PMID: 37266375 PMCID: PMC10231345 DOI: 10.1590/1678-9199-jvatitd-2022-0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 04/27/2023] [Indexed: 06/03/2023] Open
Abstract
Several regions of the world frequently use the species Moringa oleifera Lam. (Moringaceae) in traditional medicine. This situation is even more common in African countries. Many literature reports point to the antimalarial potential of this species, indicating the efficacy of its chemical compounds against malaria-causing parasites of the genus Plasmodium. From this perspective, the present study reviews the ethnobotanical, pharmacological, toxicological, and phytochemical (flavonoids) evidence of M. oleifera, focusing on the treatment of malaria. Scientific articles were retrieved from Google Scholar, PubMed®, ScienceDirect®, and SciELO databases. Only articles published between 2002 and 2022 were selected. After applying the inclusion and exclusion criteria, this review used a total of 72 articles. These documents mention a large use of M. oleifera for the treatment of malaria in African and Asian countries. The leaves (63%) of this plant are the main parts used in the preparation of herbal medicines. The in vivo antimalarial activity of M. oleifera was confirmed through several studies using polar and nonpolar extracts, fractions obtained from the extracts, infusion, pellets, and oils obtained from this plant and tested in rodents infected by the following parasites of the genus Plasmodium: P. berghei, P. falciparum, P. yoelii, and P. chabaudi. Extracts obtained from M. oleifera showed no toxicity in preclinical tests. A total of 46 flavonoids were identified in the leaves and seeds of M. oleifera by different chromatography and mass spectrometry methods. Despite the scarcity of research on the antimalarial potential of compounds isolated from M. oleifera, the positive effects against malaria-causing parasites in previous studies are likely to correlate with the flavonoids that occur in this species.
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Affiliation(s)
- José Jailson Lima Bezerra
- Graduate Program in Plant Biology, Department of Botany, Federal University of Pernambuco, Recife, PE, Brazil
| | | | - Douglas Dourado
- Graduate Program in Biosciences and Biotechnology in Health, Department of Immunology, Aggeu Magalhães-Fiocruz Institute, Recife, PE, Brazil
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13
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Guissou E, Da DF, Hien DFDS, Yameogo KB, Yerbanga SR, Ouédraogo GA, Dabiré KR, Lefèvre T, Cohuet A. Intervention reducing malaria parasite load in vector mosquitoes: No impact on Plasmodium falciparum extrinsic incubation period and the survival of Anopheles gambiae. PLoS Pathog 2023; 19:e1011084. [PMID: 37195964 DOI: 10.1371/journal.ppat.1011084] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 04/18/2023] [Indexed: 05/19/2023] Open
Abstract
In the fight against malaria, transmission blocking interventions (TBIs) such as transmission blocking vaccines or drugs, are promising approaches to complement conventional tools. They aim to prevent the infection of vectors and thereby reduce the subsequent exposure of a human population to infectious mosquitoes. The effectiveness of these approaches has been shown to depend on the initial intensity of infection in mosquitoes, often measured as the mean number of oocysts resulting from an infectious blood meal in absence of intervention. In mosquitoes exposed to a high intensity of infection, current TBI candidates are expected to be ineffective at completely blocking infection but will decrease parasite load and therefore, potentially also affect key parameters of vector transmission. The present study investigated the consequences of changes in oocyst intensity on subsequent parasite development and mosquito survival. To address this, we experimentally produced different intensities of infection for Anopheles gambiae females from Burkina Faso by diluting gametocytes from three natural Plasmodium falciparum local isolates and used a newly developed non-destructive method based on the exploitation of mosquito sugar feeding to track parasite and mosquito life history traits throughout sporogonic development. Our results indicate the extrinsic incubation period (EIP) of P. falciparum and mosquito survival did not vary with parasite density but differed significantly between parasite isolates with estimated EIP50 of 16 (95% CI: 15-18), 14 (95% CI: 12-16) and 12 (95% CI: 12-13) days and median longevity of 25 (95% CI: 22-29), 15 (95% CI: 13-15) and 18 (95% CI: 17-19) days for the three isolates respectively. Our results here do not identify unintended consequences of the decrease of parasite loads in mosquitoes on the parasite incubation period or on mosquito survival, two key parameters of vectorial capacity, and hence support the use of transmission blocking strategies to control malaria.
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Affiliation(s)
- Edwige Guissou
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
- MIVEGEC, Montpellier University, IRD, CNRS, Montpellier, France
- Université Nazi Boni, Bobo-Dioulasso, Burkina Faso
- Ecole Normale Supérieure, Koudougou, Burkina Faso
| | - Dari Frédéric Da
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | | | | | | | | | | | - Thierry Lefèvre
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
- MIVEGEC, Montpellier University, IRD, CNRS, Montpellier, France
| | - Anna Cohuet
- MIVEGEC, Montpellier University, IRD, CNRS, Montpellier, France
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14
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Imlay LS, Lawong AK, Gahalawat S, Kumar A, Xing C, Mittal N, Wittlin S, Churchyard A, Niederstrasser H, Crespo-Fernandez B, Posner BA, Gamo FJ, Baum J, Winzeler EA, LALEU B, Ready JM, Phillips MA. Fast-Killing Tyrosine Amide (( S)-SW228703) with Blood- and Liver-Stage Antimalarial Activity Associated with the Cyclic Amine Resistance Locus ( PfCARL). ACS Infect Dis 2023; 9:527-539. [PMID: 36763526 PMCID: PMC10053980 DOI: 10.1021/acsinfecdis.2c00527] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Current malaria treatments are threatened by drug resistance, and new drugs are urgently needed. In a phenotypic screen for new antimalarials, we identified (S)-SW228703 ((S)-SW703), a tyrosine amide with asexual blood and liver stage activity and a fast-killing profile. Resistance to (S)-SW703 is associated with mutations in the Plasmodium falciparum cyclic amine resistance locus (PfCARL) and P. falciparum acetyl CoA transporter (PfACT), similarly to several other compounds that share features such as fast activity and liver-stage activity. Compounds with these resistance mechanisms are thought to act in the ER, though their targets are unknown. The tyramine of (S)-SW703 is shared with some reported PfCARL-associated compounds; however, we observed that strict S-stereochemistry was required for the activity of (S)-SW703, suggesting differences in the mechanism of action or binding mode. (S)-SW703 provides a new chemical series with broad activity for multiple life-cycle stages and a fast-killing mechanism of action, available for lead optimization to generate new treatments for malaria.
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Affiliation(s)
- Leah S. Imlay
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Aloysus K. Lawong
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Suraksha Gahalawat
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Ashwani Kumar
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Chao Xing
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Nimisha Mittal
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093, USA
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland
- University of Basel, 4002, Basel, Switzerland
| | - Alisje Churchyard
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Hanspeter Niederstrasser
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | | | - Bruce A. Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | | | - Jake Baum
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
- School of Biomedical Sciences, University of New South Wales, Kensington, NSW, Australia
| | - Elizabeth A. Winzeler
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093, USA
| | - Benoît LALEU
- Medicines for Malaria Venture, 1215 Geneva 15, Switzerland
| | - Joseph M. Ready
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Margaret A. Phillips
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
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15
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Webster R, Mitchell H, Peters JM, Heunis J, O'Neill B, Gower J, Lynch S, Jennings H, Amante FH, Llewellyn S, Marquart L, Potter AJ, Birrell GW, Edstein MD, Shanks GD, McCarthy JS, Barber BE. Transmission Blocking Activity of Low-dose Tafenoquine in Healthy Volunteers Experimentally Infected With Plasmodium falciparum. Clin Infect Dis 2023; 76:506-512. [PMID: 35731843 DOI: 10.1093/cid/ciac503] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 06/13/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Blocking the transmission of parasites from humans to mosquitoes is a key component of malaria control. Tafenoquine exhibits activity against all stages of the malaria parasite and may have utility as a transmission blocking agent. We aimed to characterize the transmission blocking activity of low-dose tafenoquine. METHODS Healthy adults were inoculated with Plasmodium falciparum 3D7-infected erythrocytes on day 0. Piperaquine was administered on days 9 and 11 to clear asexual parasitemia while allowing gametocyte development. A single 50-mg oral dose of tafenoquine was administered on day 25. Transmission was determined by enriched membrane feeding assays predose and at 1, 4, and 7 days postdose. Artemether-lumefantrine was administered following the final assay. Outcomes were the reduction in mosquito infection and gametocytemia after tafenoquine and safety parameters. RESULTS Six participants were enrolled, and all were infective to mosquitoes before tafenoquine, with a median 86% (range, 22-98) of mosquitoes positive for oocysts and 57% (range, 4-92) positive for sporozoites. By day 4 after tafenoquine, the oocyst and sporozoite positivity rate had reduced by a median 35% (interquartile range [IQR]: 16-46) and 52% (IQR: 40-62), respectively, and by day 7, 81% (IQR 36-92) and 77% (IQR 52-98), respectively. The decline in gametocyte density after tafenoquine was not significant. No significant participant safety concerns were identified. CONCLUSIONS Low-dose tafenoquine (50 mg) reduces P. falciparum transmission to mosquitoes, with a delay in effect.
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Affiliation(s)
- Rebecca Webster
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Hayley Mitchell
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jenny M Peters
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Juanita Heunis
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Brighid O'Neill
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jeremy Gower
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Sean Lynch
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Helen Jennings
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Fiona H Amante
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | | | | | - Adam J Potter
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Geoffrey W Birrell
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
| | - Michael D Edstein
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
| | - G Dennis Shanks
- Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
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16
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Yahiya S, Saunders CN, Hassan S, Straschil U, Fischer OJ, Rueda-Zubiaurre A, Haase S, Vizcay-Barrena G, Famodimu MT, Jordan S, Delves MJ, Tate EW, Barnard A, Fuchter MJ, Baum J. A novel class of sulphonamides potently block malaria transmission by targeting a Plasmodium vacuole membrane protein. Dis Model Mech 2023; 16:dmm049950. [PMID: 36715290 PMCID: PMC9934914 DOI: 10.1242/dmm.049950] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/13/2022] [Indexed: 01/31/2023] Open
Abstract
Phenotypic cell-based screens are critical tools for discovering candidate drugs for development, yet identification of the cellular target and mode of action of a candidate drug is often lacking. Using an imaging-based screen, we recently discovered an N-[(4-hydroxychroman-4-yl)methyl]-sulphonamide (N-4HCS) compound, DDD01035881, that blocks male gamete formation in the malaria parasite life cycle and subsequent transmission of the parasite to the mosquito with nanomolar activity. To identify the target(s) of DDD01035881, and of the N-4HCS class of compounds more broadly, we synthesised a photoactivatable derivative, probe 2. Photoaffinity labelling of probe 2 coupled with mass spectrometry identified the 16 kDa Plasmodium falciparum parasitophorous vacuole membrane protein Pfs16 as a potential parasite target. Complementary methods including cellular thermal shift assays confirmed that the parent molecule DDD01035881 stabilised Pfs16 in lysates from activated mature gametocytes. Combined with high-resolution, fluorescence and electron microscopy data, which demonstrated that parasites inhibited with N-4HCS compounds phenocopy the targeted deletion of Pfs16 in gametocytes, these data implicate Pfs16 as a likely target of DDD01035881. This finding establishes N-4HCS compounds as being flexible and effective starting candidates from which transmission-blocking antimalarials can be developed in the future.
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Affiliation(s)
- Sabrina Yahiya
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Charlie N. Saunders
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Sarah Hassan
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Ursula Straschil
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Oliver J. Fischer
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Ainoa Rueda-Zubiaurre
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Silvia Haase
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Mufuliat Toyin Famodimu
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Sarah Jordan
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Michael J. Delves
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
| | - Edward W. Tate
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Anna Barnard
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Matthew J. Fuchter
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London W12 OBZ, UK
| | - Jake Baum
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, UK
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17
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A Novel Ex Vivo Drug Assay for Assessing the Transmission-Blocking Activity of Compounds on Field-Isolated Plasmodium falciparum Gametocytes. Antimicrob Agents Chemother 2022; 66:e0100122. [PMID: 36321830 PMCID: PMC9764978 DOI: 10.1128/aac.01001-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The discovery and development of transmission-blocking therapies challenge malaria elimination and necessitate standard and reproducible bioassays to measure the blocking properties of antimalarial drugs and candidate compounds. Most of the current bioassays evaluating the transmission-blocking activity of compounds rely on laboratory-adapted Plasmodium strains. Transmission-blocking data from clinical gametocyte isolates could help select novel transmission-blocking candidates for further development. Using freshly collected Plasmodium falciparum gametocytes from asymptomatic individuals, we first optimized ex vivo culture conditions to improve gametocyte viability and infectiousness by testing several culture parameters. We next pre-exposed ex vivo field-isolated gametocytes to chloroquine, dihydroartemisinin, primaquine, KDU691, GNF179, and oryzalin for 48 h prior to direct membrane feeding. We measured the activity of the drug on the ability of gametocytes to resume the sexual life cycle in Anopheles after drug exposure. Using 57 blood samples collected from Malian volunteers aged 6 to 15 years, we demonstrate that the infectivity of freshly collected field gametocytes can be preserved and improved ex vivo in a culture medium supplemented with 10% horse serum at 4% hematocrit for 48 h. Moreover, our optimized drug assay displays the weak transmission-blocking activity of chloroquine and dihydroartemisinin, while primaquine and oryzalin exhibited a transmission-blocking activity of ~50% at 1 μM. KDU691 and GNF179 both interrupted Plasmodium transmission at 1 μM and 5 nM, respectively. This new approach, if implemented, has the potential to accelerate the screening of compounds with transmission-blocking activity.
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18
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Morais CMG, Brito RMDM, Weselucha-Birczyńska A, Pereira VSDS, Pereira-Silva JW, Menezes A, Pessoa FAC, Kucharska M, Birczyńska-Zych M, Ríos-Velásquez CM, de Andrade-Neto VF. Blood-stage antiplasmodial activity and oocyst formation-blockage of metallo copper-cinchonine complex. Front Cell Infect Microbiol 2022; 12:1047269. [PMID: 36530433 PMCID: PMC9751060 DOI: 10.3389/fcimb.2022.1047269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 11/08/2022] [Indexed: 12/03/2022] Open
Abstract
In the fight against malaria, the key is early treatment with antimalarial chemotherapy, such as artemisinin-based combination treatments (ACTs). However, Plasmodium has acquired multidrug resistance, including the emergence of P. falciparum strains with resistance to ACT. The development of novel antimalarial molecules, that are capable of interfering in the asexual and sexual blood stages, is important to slow down the transmission in endemic areas. In this work, we studied the ability of the mettalo copper-cinchonine complex to interfere in the sexual and asexual stages of Plasmodium. The tested compound in the in vitro assay was a cinchonine derivative, named CinCu (Bis[Cinchoninium Tetrachlorocuprate(II)]trihydrate). Its biological functions were assessed by antiplasmodial activity in vitro against chloroquine-resistant P. falciparum W2 strain. The mice model of P. berghei ANKA infection was used to analyze the antimalarial activity of CinCu and chloroquine and their acute toxicity. The oocyst formation-blocking assay was performed by experimental infection of Anopheles aquasalis with P. vivax infected blood, which was treated with different concentrations of CinCu, cinchonine, and primaquine. We found that CinCu was able to suppress as high as 81.58% of parasitemia in vitro, being considered a molecule with high antiplasmodial activity and low toxicity. The in vivo analysis showed that CinCu suppressed parasitemia at 34% up to 87.19%, being a partially active molecule against the blood-stage forms of P. berghei ANKA, without inducing severe clinical signs in the treated groups. The transmission-blocking assay revealed that both cinchonine and primaquine were able to reduce the infection intensity of P. vivax in A. aquasalis, leading to a decrease in the number of oocysts recovered from the mosquitoes' midgut. Regarding the effect of CinCu, the copper-complex was not able to induce inhibition of P. vivax infection; however, it was able to induce an important reduction in the intensity of oocyst formation by about 2.4 times. It is plausible that the metallo-compound also be able to interfere with the differentiation of parasite stages and/or ookinete-secreted chitinase into the peritrophic matrix of mosquitoes, promoting a reduction in the number of oocysts formed. Taken together, the results suggest that this compound is promising as a prototype for the development of new antimalarial drugs. Furthermore, our study can draw a new pathway for repositioning already-known antimalarial drugs by editing their chemical structure to improve the antimalarial activity against the asexual and sexual stages of the parasite.
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Affiliation(s)
- Camila Martins Gomes Morais
- Laboratory of Malaria and Toxoplasmosis Biology, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil,Post-Graduate Program in Parasitic Biology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Ramayana Morais de Medeiros Brito
- Laboratory of Malaria and Toxoplasmosis Biology, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil,Laboratory of Immunology and Genomics of Parasites, Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Valeska Santana de Sena Pereira
- Laboratory of Malaria and Toxoplasmosis Biology, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil,Post-Graduate Program in Biochemistry and Molecular Biology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Jordam William Pereira-Silva
- Laboratory of Infectious Disease Ecology in the Amazon, Leônidas and Maria Deane Institute, Fiocruz, Manaus, AM, Brazil,Post-Graduate Program in Living Conditions and Health Situations in the Amazon, Leônidas and Maria Deane Institute, Fiocruz, Manaus, AM, Brazil
| | - Alexandre Menezes
- Post-Graduate Program in Biology of Host-Pathogen interaction, Leônidas and Maria Deane Institute, Fiocruz, Manaus, AM, Brazil
| | - Felipe Arley Costa Pessoa
- Laboratory of Infectious Disease Ecology in the Amazon, Leônidas and Maria Deane Institute, Fiocruz, Manaus, AM, Brazil
| | - Martyna Kucharska
- Department of Chemical Physics, Faculty of Chemistry, Jagiellonian University, Kraków, Poland
| | - Malwina Birczyńska-Zych
- Department of Infectious and Tropical Diseases, Medical College, Jagiellonian University, Kraków, Poland,Department of Infectious Diseases, The University Hospital in Kraków, Kraków, Poland
| | - Claudia María Ríos-Velásquez
- Laboratory of Infectious Disease Ecology in the Amazon, Leônidas and Maria Deane Institute, Fiocruz, Manaus, AM, Brazil,*Correspondence: Valter Ferreira de Andrade-Neto, ; ; Claudia María Ríos-Velásquez, ;
| | - Valter Ferreira de Andrade-Neto
- Laboratory of Malaria and Toxoplasmosis Biology, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil,*Correspondence: Valter Ferreira de Andrade-Neto, ; ; Claudia María Ríos-Velásquez, ;
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19
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Al-Quhaiti MAA, Abdul-Ghani R, Mahdy MAK, Assada MA. Malaria among under-five children in rural communities of Al-Mahweet governorate, Yemen. Malar J 2022; 21:344. [PMID: 36401272 PMCID: PMC9675118 DOI: 10.1186/s12936-022-04371-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 11/07/2022] [Indexed: 11/19/2022] Open
Abstract
Background Malaria burden among under-five children living in endemic areas of Yemen is largely unknown due to the lack of community-based studies. Therefore, this study determined the prevalence and risk factors associated with falciparum malaria among under-five children in rural communities of Al-Mahweet governorate, Yemen. Methods This community-based, cross-sectional study recruited 400 under-five children from two rural districts of Al-Mahweet governorate in December 2019. Demographic characteristics (gender, age, education and occupation of the child’s parents, and household size) and risk factors associated with malaria were collected through interviews with children’s caregivers using a structured questionnaire. Finger-prick blood was screened for Plasmodium falciparum and non-falciparum species using rapid diagnostic tests (RDTs), and duplicate Giemsa-stained thick and thin blood films were examined for malaria parasites. The density of asexual P. falciparum stages was also estimated. Data were then analysed, and the agreement between the results of thick-film microscopy and RDTs for diagnosing falciparum malaria was assessed using the kappa index. Statistical significance was set at a P-value of < 0.05. Results Plasmodium falciparum was prevalent among 9.8% (95% CI 7.0–13.1) of under-five children in the rural communities of Al-Mahweet, with a median asexual parasite density of 763 ± 2606 parasites/μl of blood (range: 132–4280) and low-to-moderate parasitaemia levels. Approximately one-third of microscopy-confirmed cases were gametocyte carriers. Multivariable logistic regression analysis confirmed that age of three years or older (AOR = 5.6, 95% CI 1.6–19.8; P = 0.007), not sleeping under a mosquito net the previous night of the survey (AOR = 8.0, 95% CI 2.4–27.4; P = 0.001), sleeping outdoors at night (AOR = 4.4, 95% CI 2.0–10.0; P < 0.001), and absence of indoor residual spraying (IRS) during the last year (AOR = 4.2, 95% CI 1.9–9.4; P < 0.001) were the independent predictors of falciparum malaria among under-five children in the rural communities of Al-Mahweet. The observed percentage agreement between thick-film microscopy and RDTs was 98.5%, with a very good agreement (k-index = 0.9) between the two methods for falciparum malaria diagnosis that was statistically significant. Conclusion Approximately one in ten under-five children in rural communities of Al-Mahweet is infected with P. falciparum based on microscopy and RDTs. Age of three years or older, not sleeping under mosquito nets, sleeping outdoors at night and absence of IRS can independently predict falciparum malaria among them. The very good agreement between thick-film microscopy and RDTs for diagnosing falciparum malaria in children supports the usefulness of using RDTs in such resource-limited rural communities.
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Antiplasmodial Activity of 80% Methanolic Extract and Solvent Fractions of Stem Bark of Acacia tortilis in Swiss Albino Mice. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2022; 2022:7493294. [PMID: 36387357 PMCID: PMC9652074 DOI: 10.1155/2022/7493294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 10/22/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
Abstract
Background Malarial infection has significant negative impact on the health of the world population. It is treated by modern and traditional medicines. Among traditional medicinal plants, Acacia tortilis is used by different communities as antimalarial agent. Therefore, the objective of this study is to validate antimalarial activity of the stem bark of Acacia tortilis in mice. Methods To evaluate antimalarial activity of the plant, 4-day suppressive, curative, and prophylactic antimalarial test models were used. Parasitemia, packed cell volume (PCV), survival time, rectal temperature, and body weight were used to evaluate the effect of the plant extracts. Data were analyzed using SPSS version 26 followed by Tukey's post hoc multiple comparison test. Results The crude extract and dichloromethane fraction significantly suppressed the level of parasitemia (p < 0.001) and increased mean survival time (p < 0.01) at all tested doses. Similarly, significant effects were observed in mean survival time, % change of PCV, weight, and temperature in both curative and prophylactic antimalarial test models. Conclusions The methanolic extract and solvent fractions of the stem bark of Acacia tortilis has shown antimalarial activity, and the finding supports the traditional use and the in vitro studies. Thus, this study can be used as an initiation for researchers to find the most active phytochemical entity and to conduct additional safety and efficacy tests.
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Reader J, Opperman DFL, van der Watt ME, Theron A, Leshabane M, da Rocha S, Turner J, Garrabrant K, Piña I, Mills C, Woster PM, Birkholtz L. New Transmission-Selective Antimalarial Agents through Hit-to-Lead Optimization of 2-([1,1'-Biphenyl]-4-carboxamido)benzoic Acid Derivatives. Chembiochem 2022; 23:e202200427. [PMID: 36106425 PMCID: PMC10946866 DOI: 10.1002/cbic.202200427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/14/2022] [Indexed: 11/12/2022]
Abstract
Malaria elimination requires multipronged approaches, including the application of antimalarial drugs able to block human-to-mosquito transmission of malaria parasites. The transmissible gametocytes of Plasmodium falciparum seem to be highly sensitive towards epidrugs, particularly those targeting demethylation of histone post-translational marks. Here, we report exploration of compounds from a chemical library generated during hit-to-lead optimization of inhibitors of the human histone lysine demethylase, KDM4B. Derivatives of 2-([1,1'-biphenyl]-4-carboxamido) benzoic acid, around either the amide or a sulfonamide linker backbone (2-(arylcarboxamido)benzoic acid, 2-carboxamide (arylsulfonamido)benzoic acid and N-(2-(1H-tetrazol-5-yl)phenyl)-arylcarboxamide), showed potent activity towards late-stage gametocytes (stage IV/V) of P. falciparum, with the most potent compound reaching single digit nanomolar activity. Structure-activity relationship trends were evident and frontrunner compounds also displayed microsomal stability and favourable solubility profiles. Simplified synthetic routes support further derivatization of these compounds for further development of these series as malaria transmission-blocking agents.
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Affiliation(s)
- Janette Reader
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
| | - Daniel F. L. Opperman
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
| | - Mariëtte E. van der Watt
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
- School of Health Systems and Public HealthUniversity of Pretoria, HatfieldPretoria0028South Africa
| | - Anjo Theron
- Next Generation HealthCouncil for Scientific and Industrial ResearchPretoria0001South Africa
| | - Meta Leshabane
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
| | - Shanté da Rocha
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
| | - Jonathan Turner
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Kathleen Garrabrant
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Ivett Piña
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Catherine Mills
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Patrick M. Woster
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Lyn‐Marié Birkholtz
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
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Mianda SM, Invernizzi L, van der Watt ME, Reader J, Moyo P, Birkholtz LM, Maharaj VJ. In vitro dual activity of Aloe marlothii roots and its chemical constituents against Plasmodium falciparum asexual and sexual stage parasites. JOURNAL OF ETHNOPHARMACOLOGY 2022; 297:115551. [PMID: 35850311 DOI: 10.1016/j.jep.2022.115551] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Aloe marlothii A.Berger (Xanthorrhoeaceae) is indigenous to southern African countries where its aqueous preparations are used in traditional medicine to treat several ailments including hypertension, respiratory infections, venereal diseases, chest pain, sore throat and malaria. AIM OF THE STUDY The aims of this study were as follows: (i) isolate and identify the antiplasmodial active compounds in A. marlothii roots. As the water extract was previously inactive, the dichloromethane:methanol (DCM:MeOH) (1:1) was used, (ii) examine the activity of the isolated compounds against Plasmodium falciparum asexual blood stage (ABS) parasites as well as for transmission-blocking activity against gametocytes and gametes, and (iii) to use in silico tools to predict the target(s) of the active molecules. MATERIALS AND METHODS The crude DCM:MeOH (1:1) extract of A. marlothii roots was fractionated on a reverse phase C8 column, using a positive pressure solid-phase extraction (ppSPE) workstation to produce seven fractions. The resulting fractions and the crude DCM:MeOH extract were tested in vitro against P. falciparum (NF54) ABS parasites using the malaria SYBR Green I based-fluorescence assay. Flash silica chromatography and mass-directed preparative high-performance liquid chromatography were utilised to isolate the active compounds. The isolated compounds were evaluated in vitro against P. falciparum asexual (NF54 and K1 strains) and sexual (gametocytes and gametes) stage parasites. Molecular docking was then used for the in silico prediction of targets for the isolated active compounds in P. falciparum. RESULTS The crude extract and two SPE fractions displayed good antiplasmodial activity with >97% and 100% inhibition of ABS parasites proliferation at 10 and 20 μg/mL, respectively. Following UPLC-MS analysis of these active fractions, a targeted purification resulted in the isolation of six compounds identified as aloesaponol I (1), aloesaponarin I (2), aloesaponol IV (3), β-sorigenin-1-O-methylether (4), emodin (5), and chrysophanol (6). Aloesaponarin I (2) was the most bioactive, compared to other isolated constituents, against P. falciparum ABS parasites exhibiting equipotency against the drug-sensitive (NF54) (IC50 = 1.54 μg/mL (5 μM)) and multidrug-resistant (K1) (IC50 = 1.58 μg/mL (5 μM)) strains. Aloesaponol IV (3) showed pronounced activity against late-stage (>90% stage IV/V) gametocytes (IC50 = 6.53 μg/mL (22.6 μM)) demonstrating a 3-fold selective potency towards these sexual stages compared to asexual forms of the parasite (IC50 = 19.77 ± 6.835 μg/mL (68 μM)). Transmission-blocking potential of aloesaponol IV (3) was validated by in vitro inhibition of exflagellation of male gametes (94% inhibition at 20 μg/mL). In silico studies identified β-hematin and DNA topoisomerase II as potential biological targets of compounds 2 and 3, respectively. CONCLUSION The findings from our study substantiate the traditional use of A. marlothii to treat malaria. To our knowledge, this study has provided the first report on the isolation and identification of antiplasmodial compounds from A. marlothii roots. Furthermore, our study has provided the first report on the transmission-blocking potential of one of the compounds from the genus Aloe, motivating for the investigation of other species within this genus for their potential P. falciparum transmission-blocking activity.
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Affiliation(s)
- Sephora Mutombo Mianda
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa.
| | - Luke Invernizzi
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa.
| | - Mariëtte E van der Watt
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Hatfield, Pretoria, 0028, South Africa; Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Gezina, Pretoria, 0031, South Africa.
| | - Janette Reader
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Hatfield, Pretoria, 0028, South Africa.
| | - Phanankosi Moyo
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa; Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Hatfield, Pretoria, 0028, South Africa.
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Hatfield, Pretoria, 0028, South Africa.
| | - Vinesh J Maharaj
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa.
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Jia X, Liu F, Bai J, Zhang Y, Cui L, Cao Y, Luo E. Phosphatase inhibitors BVT-948 and alexidine dihydrochloride inhibit sexual development of the malaria parasite Plasmodium berghei. Int J Parasitol Drugs Drug Resist 2022; 19:81-88. [PMID: 35792443 PMCID: PMC9260261 DOI: 10.1016/j.ijpddr.2022.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/18/2022] [Accepted: 06/22/2022] [Indexed: 11/20/2022]
Abstract
Background With the emergence of resistance to front-line antimalarials, there is an urgent need to develop new medicines, including those targeting sexual development. This study aimed to assess the activity of a panel of phosphatase inhibitors against the sexual development of Plasmodium berghei and evaluate their potential as transmission-blocking agents. Methods Twenty-five compounds were screened for transmission-blocking activity in vitro using the P. berghei ookinete culture assay. The inhibitory effects on male gametogenesis, gamete-ookinete, and zygote-ookinete formation were evaluated. The transmission-blocking activity of two compounds was evaluated using an in vivo mosquito feeding assay. Their cytotoxic effects were assessed on the human cell line HepG2. Results Twelve compounds inhibited P. berghei ookinete formation with an IC50 < 10 μM. Two compounds, BVT-948 and alexidine dihydrochloride, significantly inhibited different developmental stages from gametogenesis through ookinete maturation. They also showed a substantial in vivo transmission-blocking activity by the mosquito feeding assay. Conclusions Some phosphatase inhibitors effectively inhibited Plasmodium sexual development and exhibited evident transmission-blocking activity, suggesting that phosphatases are valid targets for antimalarial development. BVT-948 and alexidine·2HCl inhibit sexual developmental stages of Plasmodium. BVT-948 and alexidine·2HCl show a substantial transmission-blocking activity. BVT-948 and alexidine·2HCl show a relatively low cytotoxicity to HepG2 cells. Phosphatases are valid targets for antimalarial development.
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Affiliation(s)
- Xitong Jia
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Jie Bai
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China
| | - Yongzhe Zhang
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China; Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612-9415, USA
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China.
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110122, China.
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Reader J, van der Watt ME, Birkholtz LM. Streamlined and Robust Stage-Specific Profiling of Gametocytocidal Compounds Against Plasmodium falciparum. Front Cell Infect Microbiol 2022; 12:926460. [PMID: 35846744 PMCID: PMC9282888 DOI: 10.3389/fcimb.2022.926460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/30/2022] [Indexed: 12/29/2022] Open
Abstract
Malaria elimination is dependent on the ability to target both the pathogenic and transmissible stages of the human malaria parasite, Plasmodium falciparum. These forms of the parasite are differentiated by unique developmental stages, each with their own biological mechanisms and processes. These individual stages therefore also respond differently to inhibitory compounds, and this complicates the discovery of multistage active antimalarial agents. The search for compounds with transmission-blocking activity has focused on screening for activity on mature gametocytes, with only limited descriptions available for the activity of such compounds on immature stage gametocytes. This therefore poses a gap in the profiling of antimalarial agents for pan-reactive, multistage activity to antimalarial leads. Here, we optimized an effective and robust strategy for the simple and cost-effective description of the stage-specific action of gametocytocidal antimalarial compounds.
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Affiliation(s)
- Janette Reader
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Mariette E. van der Watt
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- *Correspondence: Lyn-Marié Birkholtz,
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van der Watt ME, Reader J, Birkholtz LM. Adapt or Die: Targeting Unique Transmission-Stage Biology for Malaria Elimination. Front Cell Infect Microbiol 2022; 12:901971. [PMID: 35755845 PMCID: PMC9218253 DOI: 10.3389/fcimb.2022.901971] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/06/2022] [Indexed: 12/25/2022] Open
Abstract
Plasmodium parasites have a complex life cycle that includes development in the human host as well as the Anopheles vector. Successful transmission of the parasite between its host and vector therefore requires the parasite to balance its investments in asexual replication and sexual reproduction, varying the frequency of sexual commitment to persist within the human host and generate future opportunities for transmission. The transmission window is extended further by the ability of stage V gametocytes to circulate in peripheral blood for weeks, whereas immature stage I to IV gametocytes sequester in the bone marrow and spleen until final maturation. Due to the low gametocyte numbers in blood circulation and with the ease of targeting such life cycle bottlenecks, transmission represents an efficient target for therapeutic intervention. The biological process of Plasmodium transmission is a multistage, multifaceted process and the past decade has seen a much deeper understanding of the molecular mechanisms and regulators involved. Clearly, specific and divergent processes are used during transmission compared to asexual proliferation, which both poses challenges but also opportunities for discovery of transmission-blocking antimalarials. This review therefore presents an update of our molecular understanding of gametocyte and gamete biology as well as the status of transmission-blocking activities of current antimalarials and lead development compounds. By defining the biological components associated with transmission, considerations for the development of new transmission-blocking drugs to target such untapped but unique biology is suggested as an important, main driver for transmission-blocking drug discovery.
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Affiliation(s)
- Mariëtte E van der Watt
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Janette Reader
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
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Gametocyte-specific and all-blood-stage transmission-blocking chemotypes discovered from high throughput screening on Plasmodium falciparum gametocytes. Commun Biol 2022; 5:547. [PMID: 35668202 PMCID: PMC9170688 DOI: 10.1038/s42003-022-03510-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 05/19/2022] [Indexed: 11/25/2022] Open
Abstract
Blocking Plasmodium falciparum human-to-mosquito transmission is essential for malaria elimination, nonetheless drugs killing the pathogenic asexual stages are generally inactive on the parasite transmissible stages, the gametocytes. Due to technical and biological limitations in high throughput screening of non-proliferative stages, the search for gametocyte-killing molecules so far tested one tenth the number of compounds screened on asexual stages. Here we overcome these limitations and rapidly screened around 120,000 compounds, using not purified, bioluminescent mature gametocytes. Orthogonal gametocyte assays, selectivity assays on human cells and asexual parasites, followed by compound clustering, brought to the identification of 84 hits, half of which are gametocyte selective and half with comparable activity against sexual and asexual parasites. We validated seven chemotypes, three of which are, to the best of our knowledge, novel. These molecules are able to inhibit male gametocyte exflagellation and block parasite transmission through the Anopheles mosquito vector in a standard membrane feeding assay. This work shows that interrogating a wide and diverse chemical space, with a streamlined gametocyte HTS and hit validation funnel, holds promise for the identification of dual stage and gametocyte-selective compounds to be developed into new generation of transmission blocking drugs for malaria elimination. High-throughput screening of 120,000 compounds followed by counter-screening and validation assays reveals candidate antimalarial drugs that kill Plasmodium falciparum sexual and asexual blood stages blocking parasite transmission through mosquito.
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