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Aqilah Zahirah Norazmi N, Hafizah Mukhtar N, Ravindar L, Suhaily Saaidin A, Huda Abd Karim N, Hamizah Ali A, Kartini Agustar H, Ismail N, Yee Ling L, Ebihara M, Izzaty Hassan N. Exploring antimalarial potential: Conjugating organometallic moieties with organic fragments for enhanced efficacy. Bioorg Chem 2024; 149:107510. [PMID: 38833991 DOI: 10.1016/j.bioorg.2024.107510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/10/2024] [Accepted: 05/29/2024] [Indexed: 06/06/2024]
Abstract
In the search for novel ligands with efficacy against various diseases, particularly parasitic diseases, molecular hybridization of organometallic units into biologically active scaffolds has been hailed as an appealing strategy in medicinal chemistry. The conjugation to organometallic fragments can be achieved by an appropriate linker or by directly coordinating the existing drugs to a metal. The success of Ferroquine (FQ, SR97193), an effective chloroquine-ferrocene conjugate currently undergoing the patient-exploratory phase as a combination therapy with the novel triaminopyrimidine ZY-19489 for malaria, has sparked intense interest in organometallic compound drug discovery. We present the evolution of organometallic antimalarial agents over the last decade, focusing on the parent moiety's class and the type of organometallics involved. Four main organometallic antimalarial compounds have been chosen based on conjugated organic moieties: existing antimalarial drugs, other clinical drugs, hybrid drugs, and promising scaffolds of thiosemicarbazones, benzimidazoles, and chalcones, in particular. The presented insights contribute to the ongoing discourse on organometallic compound drug development for malaria diseases.
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Affiliation(s)
- Nur Aqilah Zahirah Norazmi
- Department of Chemical Sciences, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Nur Hafizah Mukhtar
- Department of Chemical Sciences, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Lekkala Ravindar
- Department of Chemical Sciences, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Aimi Suhaily Saaidin
- Center of Foundation Studies, Universiti Teknologi Mara, 43800 Dengkil, Selangor, Malaysia
| | - Nurul Huda Abd Karim
- Department of Chemical Sciences, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Amatul Hamizah Ali
- Department of Chemical Sciences, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Hani Kartini Agustar
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, UKM, 43600, Bangi, Selangor, Malaysia
| | - Norzila Ismail
- Department of Pharmacology, School of Medicinal Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Lau Yee Ling
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Masahiro Ebihara
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu City 501-1193, Japan
| | - Nurul Izzaty Hassan
- Department of Chemical Sciences, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.
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Ponce-Cusi R, Bravo L, Paez KJ, Pinto JA, Pilco-Ferreto N. Host-Pathogen Interaction: Biology and Public Health. Methods Mol Biol 2024; 2751:3-18. [PMID: 38265706 DOI: 10.1007/978-1-0716-3617-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Interactions between host and pathogenic microorganisms are common in nature and have a significant impact on host health, often leading to several types of infections. These interactions have evolved as a result of the ongoing battle between the host's defense mechanisms and the pathogens' invasion strategies. In this chapter, we will explore the evolution of host-pathogen interactions, explore their molecular mechanisms, examine the different stages of interaction, and discuss the development of pharmacological treatments. Understanding these interactions is crucial for improving public health, as it enables us to develop effective strategies to prevent and control infectious diseases. By gaining insights into the intricate dynamics between pathogens and their hosts, we can work towards reducing the burden of such diseases on society.
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Affiliation(s)
- Richard Ponce-Cusi
- Escuela Profesional de Medicina, Facultad de Ciencias de la Salud, Universidad Nacional de Moquegua, Moquegua, Peru.
| | - Leny Bravo
- Escuela Profesional de Medicina Humana, Universidad Privada San Juan Bautista, Lima, Peru
| | - Kevin J Paez
- Escuela Profesional de Medicina Humana - Filial Ica, Universidad Privada San Juan Bautista, Ica, Peru
| | - Joseph A Pinto
- Escuela Profesional de Medicina Humana - Filial Ica, Universidad Privada San Juan Bautista, Ica, Peru
| | - Nesstor Pilco-Ferreto
- Unidad de Posgrado. Facultad de Medicina, Universidad Nacional de San Agustín de Arequipa, Arequipa, Peru
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Gao W, Qiu Y, Zhu L, Yu X, Yang F, Chen M, He G, Liu Y, Cui L, Liu F, Zhu X, Cao Y. A dual-antigen malaria vaccine targeting Pb22 and Pbg37 was able to induce robust transmission-blocking activity. Parasit Vectors 2023; 16:455. [PMID: 38098083 PMCID: PMC10720250 DOI: 10.1186/s13071-023-06071-x] [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: 07/13/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Despite years of effort to develop an effective vaccine against malaria infection, a vaccine that provides individuals with sufficient protection against malaria illness and death in endemic areas is not yet available. The development of transmission-blocking vaccines (TBVs) is a promising strategy for malaria control. A dual-antigen malaria vaccine targeting both pre- and post-fertilization antigens could effectively improve the transmission-blocking activity of vaccines against the sexual stages of the parasite. METHODS A chimeric recombinant protein Pb22-Pbg37 (Plasmodium berghei 22-P. berghei G37) composed of 19-218 amino acids (aa) of Pb22 and the N-terminal 26-88 aa of Pbg37 was designed and expressed in the Escherichia coli expression system. The antibody titers of the fusion (Pb22-Pbg37) and mixed (Pb22+Pbg37) antigens, as well as those of Pb22 and Pbg37 single antigens were evaluated by enzyme-linked immunosorbent assay. Immunofluorescence and western blot assays were performed to test the reactivity of the antisera with the native proteins in the parasite. The induction of transmission-blocking activity (TBA) by Pb22-Pbg37 and Pb22+Pbg37 were evaluated by in vitro gametocyte activation, gamete and exflagellation center formation, ookinete conversion, and in the direct mosquito feeding assay. RESULTS The Pb22-Pbg37 fusion protein was successfully expressed in vitro. Co-administration of Pb22 and Pbg37 as a fusion or mixed protein elicited comparable antibody responses in mice and resulted in responses to both antigens. Most importantly, both the mixed and fusion antigens induced antibodies with significantly higher levels of TBA than did each of the individual antigens when administered alone. In addition, the efficacy of vaccination with the Pb22-Pbg37 fusion protein was equivalent to that of vaccination with the mixed single antigens. CONCLUSIONS Dual-antigen vaccines, which expand/lengthen the period during which the transmission-blocking antibodies can act during sexual-stage development, can provide a promising higher transmission-reducing activity compared to single antigens.
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Affiliation(s)
- Wenyan Gao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
- Department of Obstetrics, The First Affiliated Hospital of China Medical University, NO. 155, Nanjing Street, Shenyang, 110001, Liaoning, People's Republic of China
| | - Yue Qiu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
- Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, 110001, Liaoning, China
| | - Liying Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Xinxin Yu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Fan Yang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Muyan Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Gang He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Yinjie Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China.
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China.
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Manjurano A, Lyimo E, Kishamawe C, Omolo J, Mosha J, Donald M, Kazyoba P, Kapiga S, Changalucha J. Prevalence of G6PD deficiency and submicroscopic malaria parasites carriage in malaria hotspot area in Northwest, Tanzania. Malar J 2023; 22:372. [PMID: 38062464 PMCID: PMC10704740 DOI: 10.1186/s12936-023-04801-1] [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: 09/13/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND The use of primaquine for mass drug administration (MDA) is being considered as a key strategy for malaria elimination. In addition to being the only drug active against the dormant and relapsing forms of Plasmodium vivax, primaquine is the sole potent drug against mature/infectious Plasmodium falciparum gametocytes. It may prevent onward transmission and help contain the spread of artemisinin resistance. However, higher dose of primaquine is associated with the risk of acute haemolytic anaemia in individuals with a deficiency in glucose-6-phosphate dehydrogenase. In many P. falciparum endemic areas there is paucity of information about the distribution of individuals at risk of primaquine-induced haemolysis at higher dose 45 mg of primaquine. METHODS A retrospective cross-sectional study was carried out using archived samples to establish the prevalence of G6PD deficiency in a malaria hotspot area in Misungwi district, located in Mwanza region, Tanzania. Blood samples collected from individuals recruited between August and November 2010 were genotyped for G6PD deficiency and submicroscopic parasites carriage using polymerase chain reaction. RESULTS A total of 263 individuals aged between 0 and 87 were recruited. The overall prevalence of the X-linked G6PD A- mutation was 83.7% (220/263) wild type, 8% (21/263) heterozygous and 8.4% (22/263) homozygous or hemizygous. Although, assessment of the enzymatic activity to assign the phenotypes according to severity and clinical manifestation as per WHO was not carried out, the overall genotype and allele frequency for the G6PD deficiency was 16.4% and 13. 2%, respectively. There was no statistically significant difference in among the different G6PD genotypes (p > 0.05). Out of 248 samples analysed for submicroscopic parasites carriage, 58.1% (144/248) were P. falciparum positive by PCR. G6PD heterozygous deficiency were associated with carriage of submicroscopic P. falciparum (p = 0.029). CONCLUSIONS This study showed that 16.4% of the population in this part of North-western Tanzania carry the G6PD A- mutation, within the range of 15-32% seen in other parts of Africa. G6PD gene mutation is widespread and heterogeneous across the study area where primaquine would be valuable for malaria control and elimination. The maps and population estimates presented here reflect potential risk of higher dose of primaquine being associated with the risk of acute haemolytic anaemia (AHA) in individuals with a deficiency in glucose-6-phosphate dehydrogenase and call further research on mapping of G6PD deficiency in Tanzania. Therefore, screening and education programmes for G6PD deficiency is warranted in a programme of malaria elimination using a higher primaquine dose.
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Affiliation(s)
| | - Eric Lyimo
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Coleman Kishamawe
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Justin Omolo
- Mabibo Centre, National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Jacklin Mosha
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Miyaye Donald
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Paul Kazyoba
- Mabibo Centre, National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Saidi Kapiga
- Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - John Changalucha
- Mwanza Centre, National Institute for Medical Research, Mwanza, Tanzania
- Mwanza Intervention Trials Unit, National Institute for Medical Research, Mwanza, Tanzania
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Mmbaga AT, Lwetoijera DW. Current and future opportunities of autodissemination of pyriproxyfen approach for malaria vector control in urban and rural Africa. Wellcome Open Res 2023; 8:119. [PMID: 37440995 PMCID: PMC10333782 DOI: 10.12688/wellcomeopenres.19131.2] [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] [Accepted: 10/23/2023] [Indexed: 07/15/2023] Open
Abstract
Despite the progress made in reducing malaria burden, new ways to address the increasing challenges of insecticide resistance and the invasion and spread of exotic malaria vectors such as Anopheles stephensi in Africa are urgently needed. While African countries are adopting larviciding as a complementary intervention for malaria vector control, the autodissemination technology has the potential to overcome barriers associated with the identification and treatment of prolific habitats that impede conventional larviciding approaches in rural settings. The autodissemination technology as a "lure and release" strategy works by exploiting the resting behavior of gravid mosquitoes to transfer lethal concentration of biological or chemical insecticide such as pyriproxyfen (PPF), an insect growth regulator (IGRs) to their oviposition sites and result in adult emergence inhibition. Despite the evidence of the autodissemination approach to control other mosquito-borne diseases, there is growing and promising evidence for its use in controlling malaria vectors in Africa, which highlights the momentous research that needs to be sustained. This article reviews the evidence for efficacy of the autodissemination approach using PPF and discusses its potential as efficient and affordable complementary malaria vector control intervention in Africa. In the previous studies that were done in controlled semi-field environments, autodissemination with PPF demonstrated its potential in reducing densities of captive population of malaria vectors such as Anopheles gambiae and Anopheles arabiensis. Of importance, empirical evidence and biology-informed mathematical models to demonstrate the utility of the autodissemination approach to control wild populations of malaria vectors under field environment either alone or in combination with other tools are underway. Among others, the key determining factors for future introduction of this approach at scale is having scalable autodissemination devices, optimized PPF formulations, assess its integration/complementarity to existing conventional larviciding, and community perception and acceptance of the autodissemination approach.
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Affiliation(s)
- Augustino Thabiti Mmbaga
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Morogoro, P.O. Box 53, Tanzania
| | - Dickson Wilson Lwetoijera
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Morogoro, P.O. Box 53, Tanzania
- School of Life Sciences and Bio Engineering, Nelson Mandela African Institution of Science and Technology, Tengeru, Arusha, P.O. Box 447, Tanzania
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Ciubotariu II, Monroe A, Williams NA, Ogoma SB, Okumu F. Ifakara MasterClasses: lessons from leading experts on the battle against malaria. Trends Parasitol 2023; 39:607-614. [PMID: 37331883 DOI: 10.1016/j.pt.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 05/24/2023] [Indexed: 06/20/2023]
Affiliation(s)
- Ilinca I Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
| | - April Monroe
- Johns Hopkins Center for Communication Programs, Baltimore, MD, USA; Ifakara Health Institute, Ifakara, Tanzania.
| | - Nana Aba Williams
- MESA Alliance, Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain; Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
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Ouologuem DT, Dara A, Kone A, Ouattara A, Djimde AA. Plasmodium falciparum Development from Gametocyte to Oocyst: Insight from Functional Studies. Microorganisms 2023; 11:1966. [PMID: 37630530 PMCID: PMC10460021 DOI: 10.3390/microorganisms11081966] [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: 06/08/2023] [Revised: 07/06/2023] [Accepted: 07/14/2023] [Indexed: 08/27/2023] Open
Abstract
Malaria elimination may never succeed without the implementation of transmission-blocking strategies. The transmission of Plasmodium spp. parasites from the human host to the mosquito vector depends on circulating gametocytes in the peripheral blood of the vertebrate host. Once ingested by the mosquito during blood meals, these sexual forms undergo a series of radical morphological and metabolic changes to survive and progress from the gut to the salivary glands, where they will be waiting to be injected into the vertebrate host. The design of effective transmission-blocking strategies requires a thorough understanding of all the mechanisms that drive the development of gametocytes, gametes, sexual reproduction, and subsequent differentiation within the mosquito. The drastic changes in Plasmodium falciparum shape and function throughout its life cycle rely on the tight regulation of stage-specific gene expression. This review outlines the mechanisms involved in Plasmodium falciparum sexual stage development in both the human and mosquito vector, and zygote to oocyst differentiation. Functional studies unravel mechanisms employed by P. falciparum to orchestrate the expression of stage-specific functional products required to succeed in its complex life cycle, thus providing us with potential targets for developing new therapeutics. These mechanisms are based on studies conducted with various Plasmodium species, including predominantly P. falciparum and the rodent malaria parasites P. berghei. However, the great potential of epigenetics, genomics, transcriptomics, proteomics, and functional genetic studies to improve the understanding of malaria as a disease remains partly untapped because of limitations in studies using human malaria parasites and field isolates.
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Affiliation(s)
- Dinkorma T. Ouologuem
- Malaria Research and Training Center, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques, and Technologies of Bamako, Bamako 1805, Mali
| | - Antoine Dara
- Malaria Research and Training Center, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques, and Technologies of Bamako, Bamako 1805, Mali
| | - Aminatou Kone
- Malaria Research and Training Center, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques, and Technologies of Bamako, Bamako 1805, Mali
| | - Amed Ouattara
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Abdoulaye A. Djimde
- Malaria Research and Training Center, Faculty of Pharmacy, Faculty of Medicine and Dentistry, University of Sciences, Techniques, and Technologies of Bamako, Bamako 1805, Mali
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Tine R, Herrera S, Badji MA, Daniels K, Ndiaye P, Smith Gueye C, Tairou F, Slutsker L, Hwang J, Ansah E, Littrell M. Defining operational research priorities to improve malaria control and elimination in sub-Saharan Africa: results from a country-driven research prioritization setting process. Malar J 2023; 22:219. [PMID: 37517990 PMCID: PMC10387205 DOI: 10.1186/s12936-023-04654-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/22/2023] [Indexed: 08/01/2023] Open
Abstract
BACKGROUND In order to reignite gains and accelerate progress toward improved malaria control and elimination, policy, strategy, and operational decisions should be derived from high-quality evidence. The U.S. President's Malaria Initiative (PMI) Insights project together with the Université Cheikh Anta Diop of Dakar, Senegal, conducted a broad stakeholder consultation process to identify pressing evidence gaps in malaria control and elimination across sub-Saharan Africa (SSA), and developed a priority list of country-driven malaria operational research (OR) and programme evaluation (PE) topics to address these gaps. METHODS Five key stakeholder groups were engaged in the process: national malaria programmes (NMPs), research institutions in SSA, World Health Organization (WHO) representatives in SSA, international funding agencies, and global technical partners who support malaria programme implementation and research. Stakeholders were engaged through individual or small group interviews and an online survey, and asked about key operational challenges faced by NMPs, pressing evidence gaps in current strategy and implementation guidance, and priority OR and PE questions to address the challenges and gaps. RESULTS Altogether, 47 interviews were conducted with 82 individuals, and through the online survey, input was provided by 46 global technical partners. A total of 33 emergent OR and PE topics were identified through the consultation process and were subsequently evaluated and prioritized by an external evaluation committee of experts from NMPs, research institutions, and the WHO. The resulting prioritized OR and PE topics predominantly focused on generating evidence needed to close gaps in intervention coverage, address persistent challenges faced by NMPs in the implementation of core strategic interventions, and inform the effective deployment of new tools. CONCLUSION The prioritized research list is intended to serve as a key resource for informing OR and PE investments, thereby ensuring future investments focus on generating the evidence needed to strengthen national strategies and programme implementation and facilitating a more coordinated and impactful approach to malaria operational research.
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Affiliation(s)
- Roger Tine
- Université Cheikh Anta Diop, Dakar, Senegal
| | | | | | - Kyle Daniels
- PMI Insights Project/University of California, San Francisco Malaria Elimination Initiative, San Francisco, USA
| | | | - Cara Smith Gueye
- PMI Insights Project/University of California, San Francisco Malaria Elimination Initiative, San Francisco, USA
| | | | | | - Jimee Hwang
- U.S. President's Malaria Initiative, Malaria Branch, U.S. Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Evelyn Ansah
- University of Health and Allied Sciences, Accra, Ghana
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Mbassi DE, Pfaffendorf C, Mombo-Ngoma G, Kreuels B, Ramharter M. Real-life effectiveness of anti-malarial treatment regimens: what are we aiming for? Malar J 2023; 22:189. [PMID: 37340324 DOI: 10.1186/s12936-023-04606-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 05/25/2023] [Indexed: 06/22/2023] Open
Abstract
Three-day artemisinin-based combination therapy (ACT) is the current standard of care for the treatment of malaria. However, specific drug resistance associated with reduced efficacy of ACT has been observed, therefore necessitating the clinical development of new anti-malarial drugs and drug combinations. Previously, Single Encounter Radical Cure and Prophylaxis (SERCAP) has been proposed as ideal target-product-profile for any new anti-malarial drug regimen as this would improve treatment adherence besides ensuring complete cure and prevention of early reinfection. Arguably, this concept may not be ideal as it (1) necessitates administration of an excessively high dose of drug to achieve plasmodicidal plasma levels for a sufficient time span, (2) increases the risk for drug related adverse drug reactions, and (3) leaves the patient with a one-time opportunity to achieve-or not-cure by a single drug intake. Over the past years, SERCAP has led to the halt of promising drug development programmes, leading to potentially unnecessary attrition in the anti-malarial development pipeline. One proposition could be the concept of single-day multi-dose regimens as a potentially better alternative, as this allows to (1) administer a lower dose of the drug at each time-point leading to better tolerability and safety, (2) increase treatment adherence based on the intake of the anti-malarial drug within 24 h when malaria-related symptoms are still present, and (3) have more than one opportunity for adequate intake of the drug in case of early vomiting or other factors causing reduced bioavailability. In line with a recently published critical viewpoint on the concept of SERCAP, an alternative proposition is-in contrast to the current World Health Organization (WHO) treatment guidelines-to aim for less than three days, but still multiple-dose anti-malarial treatment regimens. This may help to strike the optimal balance between improving treatment adherence, maximizing treatment effectiveness, while keeping attrition of new drugs and drug regimens as low as possible.
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Affiliation(s)
- Dorothea Ekoka Mbassi
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- German Centre for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Christoph Pfaffendorf
- Department of Clinical Pharmacy, Institute of Pharmacy, University of Hamburg, 20146, Hamburg, Germany
| | - Ghyslain Mombo-Ngoma
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Benno Kreuels
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
- Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Michael Ramharter
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
- German Centre for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel, Hamburg, Germany.
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.
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Al-Amin HM, Rodriguez I, Phru CS, Khan WA, Haque R, Nahlen BL, Burton TA, Alam MS, Lobo NF. Composition of Anopheles species and bionomic characteristics over the peak malaria transmission season in Bandarban, Bangladesh. Malar J 2023; 22:176. [PMID: 37280591 DOI: 10.1186/s12936-023-04614-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/01/2023] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND Joint efforts by government and non-government organizations have helped to reduce malaria in Bangladesh and set the country on a clear path to eventual malaria elimination. However, achieving that goal would be challenging without a comprehensive understanding of vector bionomics. METHODS Targeted capturing of Anopheles mosquitoes over a rainy season, utilizing specific sampling methods, including human landing catches (HLCs), CDC-light traps (CDC-LTs), and pyrethrum spray catches (PSCs) were aimed to characterize entomological drivers of transmission in four sites of Bandarban, Bangladesh. RESULTS Molecular characterization of a subset of 4637 mosquitoes has demonstrated the presence of at least 17 species whose capture rates were representative of the rainy season. Species compositions and bionomic traits did not vary between sites with Anopheles maculatus having the highest landing rate by HLCs and Anopheles vagus having the highest capture rate with CDC-LTs. Interestingly, Anopheles species compositions and capture rates varied significantly (p < 0.05) for An. vagus, between HLCs and its often-used proxy-CDC-LTs- suggesting impacts on downstream analysis. CDC-LTs capture rates demonstrated differing compositions with indoor and outdoor biting rates. For example, Anopheles nigerrimus and Anopheles nivipes were more endophagic by HLCs and more exophagic by CDC-LTs. The use of a cow-baited CDC-LT also demonstrated significantly different results when compared to a human-baited CDC-LT considering the high degree of anthropophily in these species. The exception to both zoophily and indoor resting was An. vagus, which demonstrated both anthropophily and high resting rates indoors-pointing to this species being a possible primary vector at this site. CONCLUSION A diverse Anopheles fauna in Bandarban has been confirmed through molecular methods, highlighting the potential impact of sampling techniques. Given the complexity of the local ecosystem, a better understanding of mosquito behaviour and ecology is required to achieve the goal of malaria elimination in Bangladesh.
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Affiliation(s)
- Hasan Mohammad Al-Amin
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh.
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.
- School of Biological Sciences, University of Queensland, Brisbane, QLD, Australia.
| | - Isabella Rodriguez
- Eck Institute for Global Health (EIGH), University of Notre Dame, Notre Dame, IN, USA
| | - Ching Swe Phru
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Wasif A Khan
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Rashidul Haque
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Bernard L Nahlen
- Eck Institute for Global Health (EIGH), University of Notre Dame, Notre Dame, IN, USA
| | - Timothy A Burton
- Eck Institute for Global Health (EIGH), University of Notre Dame, Notre Dame, IN, USA
| | - Mohammad Shafiul Alam
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Neil F Lobo
- Eck Institute for Global Health (EIGH), University of Notre Dame, Notre Dame, IN, USA
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11
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Amaral LC, Salazar YEAR, de Alvarenga DAM, de Pina-Costa A, Nunes AJD, de Souza Junior JC, Gonçalves GHP, Hirano ZMB, Moreira SB, Pissinatti A, Daniel-Ribeiro CT, de Sousa TN, Alves de Brito CF. Detection of Plasmodium simium gametocytes in non-human primates from the Brazilian Atlantic Forest. Malar J 2023; 22:170. [PMID: 37268984 DOI: 10.1186/s12936-023-04601-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/20/2023] [Indexed: 06/04/2023] Open
Abstract
BACKGROUND Plasmodium species of non-human primates (NHP) are of great interest because they can naturally infect humans. Plasmodium simium, a parasite restricted to the Brazilian Atlantic Forest, was recently shown to cause a zoonotic outbreak in the state of Rio de Janeiro. The potential of NHP to act as reservoirs of Plasmodium infection presents a challenge for malaria elimination, as NHP will contribute to the persistence of the parasite. The aim of the current study was to identify and quantify gametocytes in NHP naturally-infected by P. simium. METHODS Whole blood samples from 35 NHP were used in quantitative reverse transcription PCR (RT-qPCR) assays targeting 18S rRNA, Pss25 and Pss48/45 malaria parasite transcripts. Absolute quantification was performed in positive samples for 18S rRNA and Pss25 targets. Linear regression was used to compare the quantification cycle (Cq) and the Spearman's rank correlation coefficient was used to assess the correlation between the copy numbers of 18S rRNA and Pss25 transcripts. The number of gametocytes/µL was calculated by applying a conversion factor of 4.17 Pss25 transcript copies per gametocyte. RESULTS Overall, 87.5% of the 26 samples, previously diagnosed as P. simium, were positive for 18S rRNA transcript amplification, of which 13 samples (62%) were positive for Pss25 transcript amplification and 7 samples (54%) were also positive for Pss48/45 transcript. A strong positive correlation was identified between the Cq of the 18S rRNA and Pss25 and between the Pss25 and Pss48/45 transcripts. The 18S rRNA and Pss25 transcripts had an average of 1665.88 and 3.07 copies/µL, respectively. A positive correlation was observed between the copy number of Pss25 and 18S rRNA transcripts. Almost all gametocyte carriers exhibited low numbers of gametocytes (< 1/µL), with only one howler monkey having 5.8 gametocytes/µL. CONCLUSIONS For the first time, a molecular detection of P. simium gametocytes in the blood of naturally-infected brown howler monkeys (Alouatta guariba clamitans) was reported here, providing evidence that they are likely to be infectious and transmit P. simium infection, and, therefore, may act as a reservoir of malaria infection for humans in the Brazilian Atlantic Forest.
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Affiliation(s)
- Lara Cotta Amaral
- Grupo de Pesquisa em Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, Brazil
| | | | - Denise Anete Madureira de Alvarenga
- Grupo de Pesquisa em Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, Brazil
| | - Anielle de Pina-Costa
- Laboratório de Doenças Febris Agudas, Instituto Nacional de Infectologia Evandro Chagas, Fiocruz, Rio de Janeiro, Brazil
- Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Rio de Janeiro, Brazil
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
- Departamento de Doenças Infecciosas e Parasitárias, Escola de Enfermagem Aurora de Afonso Costa, Universidade Federal Fluminense, Niterói, Brazil
| | - Ana Júlia Dutra Nunes
- Programa de Conservação do Bugio Ruivo, Joinville, Brazil
- Centro de Pesquisas Biológicas de Indaial, Indaial, Brazil
- Universidade Regional de Blumenau - FURB, Blumenau, Brazil
| | - Júlio Cesar de Souza Junior
- Centro de Pesquisas Biológicas de Indaial, Indaial, Brazil
- Universidade Regional de Blumenau - FURB, Blumenau, Brazil
| | | | - Zelinda Maria Braga Hirano
- Centro de Pesquisas Biológicas de Indaial, Indaial, Brazil
- Universidade Regional de Blumenau - FURB, Blumenau, Brazil
| | | | - Alcides Pissinatti
- Centro de Primatologia do Rio de Janeiro/INEA, Guapimirim, Brazil
- Centro Universitário Serra dos Órgãos, Teresópolis, Brazil
| | - Cláudio Tadeu Daniel-Ribeiro
- Centro de Pesquisa, Diagnóstico e Treinamento em Malária, Fiocruz, Rio de Janeiro, Brazil
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Taís Nóbrega de Sousa
- Grupo de Pesquisa em Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, Brazil
| | - Cristiana Ferreira Alves de Brito
- Grupo de Pesquisa em Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz), Belo Horizonte, Brazil.
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12
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Ramelow J, Keleta Y, Niu G, Wang X, Li J. Plasmodium parasitophorous vacuole membrane protein Pfs16 promotes malaria transmission by silencing mosquito immunity. J Biol Chem 2023:104824. [PMID: 37196765 DOI: 10.1016/j.jbc.2023.104824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 04/07/2023] [Accepted: 05/08/2023] [Indexed: 05/19/2023] Open
Abstract
With rising cases for the first time in years, malaria remains a significant public health burden. The sexual stage of the malaria parasite infects mosquitoes to transmit malaria from host to host. Hence, an infected mosquito plays an essential role in malaria transmission. Plasmodium falciparum is the most dominant and dangerous malaria pathogen. Previous studies identified a sexual stage-specific protein 16 (Pfs16) localized to the parasitophorous vacuole membrane (PVM). Here we elucidate the function of Pfs16 during malaria transmission. Our structural analysis identified Pfs16 as an alpha-helical integral membrane protein with one transmembrane domain connecting to two regions across PVM. ELISA assays showed that insect cell-expressed recombinant Pfs16 (rPfs16) interacted with An. gambiae midguts, and microscopy found that rPfs16 bound to midgut epithelial cells. Transmission-blocking assays demonstrated that polyclonal antibodies against Pfs16 significantly reduced the number of oocysts in mosquito midguts. However, on the contrary, feeding rPfs16 increased the number of oocysts. Further analysis revealed that Pfs16 reduced the activity of mosquito midgut caspase 3/7, a key enzyme in the mosquito Jun-N-terminal kinase (JNK) immune pathway. We conclude that Pfs16 facilitates parasites to invade mosquito midguts by actively silencing the mosquito's innate immunity through its interaction with the midgut epithelial cells. Therefore, Pfs16 is a potential target to control malaria transmission.
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Affiliation(s)
- Julian Ramelow
- Biomedical Sciences Graduate Program, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - Yacob Keleta
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - Guodong Niu
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - Xiaohong Wang
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - Jun Li
- Biomedical Sciences Graduate Program, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA; Department of Biological Sciences, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA.
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13
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Mmbaga AT, Lwetoijera DW. Current and future opportunities of autodissemination of pyriproxyfen approach for malaria vector control in urban and rural Africa. Wellcome Open Res 2023. [DOI: 10.12688/wellcomeopenres.19131.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
Despite the progress made in reducing malaria burden, new ways to address the increasing challenges of insecticide resistance and the invasion and spread of exotic malaria vectors such as Anopheles stephensi in Africa are urgently needed. While African countries are adopting larviciding as a complementary intervention for malaria vector control, the autodissemination technology has the potential to overcome barriers associated with the identification and treatment of prolific habitats that impede conventional larviciding approaches in rural settings. The autodissemination technology as a “lure and release” strategy works by exploiting the resting behavior of gravid mosquitoes to transfer lethal concentration of biological or chemical insecticide such as pyriproxyfen (PPF), an insect growth regulator (IGRs) to their oviposition sites and result in adult emergence. Despite the evidence of the autodissemination approach to control other mosquito-borne diseases, there is growing and promising evidence for its use in controlling malaria vectors in Africa, which highlights the momentous research that needs to be sustained. This article reviews the evidence for efficacy of the autodissemination approach using PPF and discusses its potential as efficient and affordable complementary malaria vector control intervention in Africa. In the previous studies that were done in controlled semi-field environments, autodissemination with PPF demonstrated its potential in reducing densities of captive population of malaria vectors such as Anopheles gambiae and Anopheles arabiensis. Of importance, empirical evidence and biology-informed mathematical models to demonstrate the utility of the autodissemination approach to control wild populations of malaria vectors under field environment either alone or in combination with other tools are underway. Among others, the key determining factors for future introduction of this approach at scale is having scalable autodissemination devices, optimized PPF formulations, assess its integration/complementarity to existing conventional larviciding, and community perception and acceptance of the autodissemination approach.
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14
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Andagalu B, Watson OJ, Onyango I, Opot B, Okoth R, Chemwor G, Sifuna P, Juma D, Cheruiyot A, Yeda R, Okudo C, Wafubwa J, Yalwala S, Abuom D, Ogutu B, Cowden J, Akala HM, Kamau E. Malaria Transmission Dynamics in a High-Transmission Setting of Western Kenya and the Inadequate Treatment Response to Artemether-Lumefantrine in an Asymptomatic Population. Clin Infect Dis 2023; 76:704-712. [PMID: 35767269 PMCID: PMC9938745 DOI: 10.1093/cid/ciac527] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 06/13/2022] [Accepted: 06/24/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Assessing the infectious reservoir is critical in malaria control and elimination strategies. We conducted a longitudinal epidemiological study in a high-malaria-burden region in Kenya to characterize transmission in an asymptomatic population. METHODS 488 study participants encompassing all ages in 120 households within 30 clusters were followed for 1 year with monthly sampling. Malaria was diagnosed by microscopy and molecular methods. Transmission potential in gametocytemic participants was assessed using direct skin and/or membrane mosquito feeding assays, then treated with artemether-lumefantrine. Study variables were assessed using mixed-effects generalized linear models. RESULTS Asexual and sexual parasite data were collected from 3792 participant visits, with 903 linked with feeding assays. Univariate analysis revealed that the 6-11-year-old age group was at higher risk of harboring asexual and sexual infections than those <6 years old (odds ratio [OR] 1.68, P < .001; and OR 1.81, P < .001), respectively. Participants with submicroscopic parasitemia were at a lower risk of gametocytemia compared with microscopic parasitemia (OR 0.04, P < .001), but they transmitted at a significantly higher rate (OR 2.00, P = .002). A large proportion of the study population who were infected at least once remained infected (despite treatment) with asexual (71.7%, 291/406) or sexual (37.4%, 152/406) parasites. 88.6% (365/412) of feeding assays conducted in individuals who failed treatment the previous month resulted in transmissions. CONCLUSIONS Individuals with asymptomatic infection sustain the transmission cycle, with the 6-11-year age group serving as an important reservoir. The high rates of artemether-lumefantrine treatment failures suggest surveillance programs using molecular methods need to be expanded for accurate monitoring and evaluation of treatment outcomes.
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Affiliation(s)
- Ben Andagalu
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Oliver J Watson
- Medical Research Council, Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Irene Onyango
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Benjamin Opot
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Raphael Okoth
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Gladys Chemwor
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Peter Sifuna
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Dennis Juma
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Agnes Cheruiyot
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Redemptah Yeda
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Charles Okudo
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Jackline Wafubwa
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Santos Yalwala
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - David Abuom
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | | | - Jessica Cowden
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Hoseah M Akala
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Edwin Kamau
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya.,US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA.,Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
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15
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Ivanochko D, Fabra-García A, Teelen K, van de Vegte-Bolmer M, van Gemert GJ, Newton J, Semesi A, de Bruijni M, Bolscher J, Ramjith J, Szabat M, Vogt S, Kraft L, Duncan S, Lee SM, Kamya MR, Feeney ME, Jagannathan P, Greenhouse B, Sauerwein RW, Richter King C, MacGill RS, Bousema T, Jore MM, Julien JP. Potent transmission-blocking monoclonal antibodies from naturally exposed individuals target a conserved epitope on Plasmodium falciparum Pfs230. Immunity 2023; 56:420-432.e7. [PMID: 36792575 PMCID: PMC9942874 DOI: 10.1016/j.immuni.2023.01.013] [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: 08/16/2022] [Revised: 11/04/2022] [Accepted: 01/12/2023] [Indexed: 02/16/2023]
Abstract
Pfs230 is essential for Plasmodium falciparum transmission to mosquitoes and is the protein targeted by the most advanced malaria-transmission-blocking vaccine candidate. Prior understanding of functional epitopes on Pfs230 is based on two monoclonal antibodies (mAbs) with moderate transmission-reducing activity (TRA), elicited from subunit immunization. Here, we screened the B cell repertoire of two naturally exposed individuals possessing serum TRA and identified five potent mAbs from sixteen Pfs230 domain-1-specific mAbs. Structures of three potent and three low-activity antibodies bound to Pfs230 domain 1 revealed four distinct epitopes. Highly potent mAbs from natural infection recognized a common conformational epitope that is highly conserved across P. falciparum field isolates, while antibodies with negligible TRA derived from natural infection or immunization recognized three distinct sites. Our study provides molecular blueprints describing P. falciparum TRA, informed by contrasting potent and non-functional epitopes elicited by natural exposure and vaccination.
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Affiliation(s)
- Danton Ivanochko
- Program in Molecular Medicine, the Hospital for Sick Children Research Institute, Toronto, ON, Canada
| | | | - Karina Teelen
- Department of Medical Microbiology, Radboudumc, Nijmegen, the Netherlands
| | | | | | - Jocelyn Newton
- Program in Molecular Medicine, the Hospital for Sick Children Research Institute, Toronto, ON, Canada
| | - Anthony Semesi
- Program in Molecular Medicine, the Hospital for Sick Children Research Institute, Toronto, ON, Canada
| | | | | | - Jordache Ramjith
- Radboud Institute for Health Sciences, Department for Health Evidence, Biostatistics Section, Radboudumc, Nijmegen, the Netherlands
| | | | | | - Lucas Kraft
- AbCellera Biologics Inc., Vancouver, BC, Canada
| | | | - Shwu-Maan Lee
- PATH's Malaria Vaccine Initiative, Washington, DC 20001, USA
| | - Moses R Kamya
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Margaret E Feeney
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA; Department of Pediatrics, University of California, San Francisco, San Francisco, CA, USA
| | - Prasanna Jagannathan
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, USA
| | - Bryan Greenhouse
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | | | - C Richter King
- PATH's Malaria Vaccine Initiative, Washington, DC 20001, USA
| | | | - Teun Bousema
- Department of Medical Microbiology, Radboudumc, Nijmegen, the Netherlands.
| | - Matthijs M Jore
- Department of Medical Microbiology, Radboudumc, Nijmegen, the Netherlands.
| | - Jean-Philippe Julien
- Program in Molecular Medicine, the Hospital for Sick Children Research Institute, Toronto, ON, Canada; Departments of Biochemistry and Immunology, University of Toronto, Toronto, ON, Canada.
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16
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Tang WK, Coelho CH, Miura K, Nguemwo Tentokam BC, Salinas ND, Narum DL, Healy SA, Sagara I, Long CA, Duffy PE, Tolia NH. A human antibody epitope map of Pfs230D1 derived from analysis of individuals vaccinated with a malaria transmission-blocking vaccine. Immunity 2023; 56:433-443.e5. [PMID: 36792576 PMCID: PMC9989938 DOI: 10.1016/j.immuni.2023.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/07/2022] [Accepted: 01/13/2023] [Indexed: 02/16/2023]
Abstract
Pfs230 domain 1 (Pfs230D1) is an advanced malaria transmission-blocking vaccine antigen demonstrating high functional activity in clinical trials. However, the structural and functional correlates of transmission-blocking activity are not defined. Here, we characterized a panel of human monoclonal antibodies (hmAbs) elicited in vaccinees immunized with Pfs230D1. These hmAbs exhibited diverse transmission-reducing activity, yet all bound to Pfs230D1 with nanomolar affinity. We compiled epitope-binning data for seventeen hmAbs and structures of nine hmAbs complexes to construct a high-resolution epitope map and revealed that potent transmission-reducing hmAbs bound to one face of Pfs230D1, while non-potent hmAbs bound to the opposing side. The structure of Pfs230D1D2 revealed that non-potent transmission-reducing epitopes were occluded by the second domain. The hmAb epitope map delineated binary hmAb combinations that synergized for extremely high-potency, transmission-reducing activity. This work provides a high-resolution guide for structure-based design of enhanced immunogens and informs diagnostics that measure the transmission-reducing response.
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Affiliation(s)
- Wai Kwan Tang
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Camila H Coelho
- Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Bergeline C Nguemwo Tentokam
- Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Nichole D Salinas
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David L Narum
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sara A Healy
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Issaka Sagara
- Malaria Research and Training Center, University of Sciences, Techniques, and Technology, Bamako, Mali
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Patrick E Duffy
- Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA; Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Niraj H Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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17
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Akello AR, Byagamy JP, Etajak S, Okadhi CS, Yeka A. Factors influencing consistent use of bed nets for the control of malaria among children under 5 years in Soroti District, North Eastern Uganda. Malar J 2022; 21:363. [PMID: 36461059 PMCID: PMC9716664 DOI: 10.1186/s12936-022-04396-z] [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: 05/23/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND The use of insecticide-treated bed nets has been proven to be effective in reducing malaria transmission in highly endemic areas. Use of long-lasting insecticidal nets (LLINs) has been embraced by many malaria endemic countries. LLINs are up to 95% effective in inhibiting blood feeding, when used consistently even after 7 years. The challenge, however, is enhancing their consistent use, especially by the most vulnerable groups (children under 5 years and pregnant women). The study established factors associated with consistent use of bed nets for malaria control among children under 5 years in Soroti district. METHODS The study employed a cross-sectional design, with multi-stage sampling of households. A total of 400 households (HH) were sampled and the HH head in each household interviewed. Key informant interviews (KIIs) were conducted with 7 key informants who were knowledgeable on the subject matter. Data analysis was done using SPSS 17.0 at Univariate, Bivariate and Multivariable levels; after entry and cleaning. Key informants' data were summarized manually; verbatim quotes and text used to reinforce quantitative data in line with objectives. RESULTS Only 56.8% of the 690 children under 5 years used bed nets consistently. The factors affecting consistent bed net use were age of the child, their use of bed nets the previous night, occupation of caretaker, respondents' perceived susceptibility, perceived risk of getting malaria, size and shape of the bed nets. Rectangular nets were difficult to hang daily in huts according to most key informants. CONCLUSION Consistent bed net use among under fives is still below the RBM target of 85% by 2015 and can be enhanced by providing conical bed nets and setting aside a health education programme to emphasize the effectiveness of even one mosquito in spreading malaria at night to the entire household and ability of bed nets to stop transmission better than other methods.
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Affiliation(s)
- Anne Ruth Akello
- Department of Public Health, Faculty of Health Sciences, Lira University, Lira, Uganda ,grid.11194.3c0000 0004 0620 0548Deprtment of Disease Control and Environmental Health, School of Public Health, Makerere University, Kampala, Uganda
| | - John Paul Byagamy
- Department of Public Health, Faculty of Health Sciences, Lira University, Lira, Uganda
| | - Samuel Etajak
- grid.11194.3c0000 0004 0620 0548Deprtment of Disease Control and Environmental Health, School of Public Health, Makerere University, Kampala, Uganda
| | | | - Adoke Yeka
- grid.11194.3c0000 0004 0620 0548Deprtment of Disease Control and Environmental Health, School of Public Health, Makerere University, Kampala, Uganda
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18
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Patrick SM, Cox SN, Guidera KE, Simon MJ, Kruger T, Bornman R. COVID-19 and the malaria elimination agenda in Africa: Re-shifting the focus. Glob Public Health 2022; 17:3981-3992. [PMID: 36194811 DOI: 10.1080/17441692.2022.2129729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The global Coronavirus disease 2019 (COVID-19) pandemic has resulted in public health, political, scientific and private sector response at an unprecedented scale. However, this shift in focus has caused widespread disruption to global health services and has the potential to reverse gains made in efforts to control malaria. If health systems are not able to maintain malaria control interventions while managing the response to the COVID-19 pandemic, malaria cases will increase, thereby placing even more strain on already overtaxed systems. Using a Narrative Review Approach, this commentary explores the impact of COVID-19 on progress made with malaria control and prevention strategies in Africa; and discusses possible mitigation steps to aid community resilience building, through proactive planning and implementation of integrated, inclusive and sustainable strategies to re-shift the focus to attain the malaria elimination goals. We propose strengthening community partnerships, where academia and communities should collaborate and these knowledge-sharing strategies be implemented in order for awareness and interventions to become more networked, inclusive, resilient and effective. Communities should be viewed as 'thought partners', who challenge conventional strategies and aid in developing innovative approaches to community resilience building.
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Affiliation(s)
- Sean M Patrick
- University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Sarah N Cox
- Public Health, University of Washington, Seattle, WA, USA.,One Sun Health Inc., New York, USA & Mpumalanga, ZA
| | | | | | - Taneshka Kruger
- University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Riana Bornman
- University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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19
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Yue Z, Hu B, Chen Z, Zheng G, Wang Y, Yang C, Cao P, Wu X, Liang L, Zang F, Wang J, Li J, Zhang T, Wu J, Chen H. Continuous release of mefloquine featured in electrospun fiber membranes alleviates epidural fibrosis and aids in sensory neurological function after lumbar laminectomy. Mater Today Bio 2022; 17:100469. [PMCID: PMC9633751 DOI: 10.1016/j.mtbio.2022.100469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/11/2022] [Accepted: 10/18/2022] [Indexed: 11/05/2022] Open
Abstract
Recurrent low back pain after spinal surgeries, such as lumbar laminectomy, is a major complication of excessive epidural fibrosis. Although multiple preclinical and clinical methods have been aimed at ameliorating epidural fibrosis, their safety and efficacy remain largely unclear. Single implanted electrospun fibrous membranes provide physical barriers that can decrease tissue fibrosis after surgery; however, they also trigger local inflammation due to the implantation of a foreign body, thus subsequently attenuating their anti-fibrosis properties. Here, we designed a strategy that permits easy incorporation of mefloquine into polylactic acid membranes, and stable long-term mefloquine release, to potentially improve anti-fibrosis effects and relieve or prevent low back pain. The electrospun fibrous membranes grafted with mefloquine showed a well-controlled early temporary peak release, and secondary drug release occurred smoothly over several weeks. Histopathological and histomorphometric results indicated that the drug-loaded membranes had excellent anti-fibrosis effects after laminectomy in rats. Inflammation and neovascularization at the surgical site indicated that the mefloquine-grafted electrospun fibrous membranes provided sustained anti-inflammatory outcomes while effectively alleviating associated neuropathic pain hypersensitivity. In summary, our study indicated that polylactic acid-mefloquine grafted electrospun fibrous membranes may be a potential local agent to mitigate epidural fibrosis and support sensory neurological function after laminectomy, thereby potentially improving patients’ postoperative outcomes.
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Affiliation(s)
- Zhihao Yue
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Bo Hu
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Zhe Chen
- Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Biological Science and Medical Engineering, Donghua University, Shanghai, China
| | - Genjiang Zheng
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Yunhao Wang
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Chen Yang
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Peng Cao
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Xiaodong Wu
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Lei Liang
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Fazhi Zang
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Jianxi Wang
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Jing Li
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China,Department of Bioinformatics, Center for Translational Medicine, Naval Medical University, Shanghai, 200433, China
| | - Tao Zhang
- Department of Orthopedic Surgery, Shanghai Sixth People's Hospital, 200030, Shanghai, China,Corresponding author.
| | - Jinglei Wu
- Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Biological Science and Medical Engineering, Donghua University, Shanghai, China,Corresponding author. College of Biological Science and Medical Engineering, Donghua University, Shanghai, China.
| | - Huajiang Chen
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China,Corresponding author. Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, China.
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20
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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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21
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Bouzón-Arnáiz I, Avalos-Padilla Y, Biosca A, Caño-Prades O, Román-Álamo L, Valle J, Andreu D, Moita D, Prudêncio M, Arce EM, Muñoz-Torrero D, Fernàndez-Busquets X. The protein aggregation inhibitor YAT2150 has potent antimalarial activity in Plasmodium falciparum in vitro cultures. BMC Biol 2022; 20:197. [PMID: 36271358 PMCID: PMC9587658 DOI: 10.1186/s12915-022-01374-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 07/12/2022] [Indexed: 11/25/2022] Open
Abstract
Background By 2016, signs of emergence of Plasmodium falciparum resistance to artemisinin and partner drugs were detected in the Greater Mekong Subregion. Recently, the independent evolution of artemisinin resistance has also been reported in Africa and South America. This alarming scenario calls for the urgent development of new antimalarials with novel modes of action. We investigated the interference with protein aggregation, which is potentially toxic for the cell and occurs abundantly in all Plasmodium stages, as a hitherto unexplored drug target in the pathogen. Results Attempts to exacerbate the P. falciparum proteome’s propensity to aggregation by delivering endogenous aggregative peptides to in vitro cultures of this parasite did not significantly affect their growth. In contrast, protein aggregation inhibitors clearly reduced the pathogen’s viability. One such compound, the bis(styrylpyridinium) salt YAT2150, exhibited potent antiplasmodial activity with an in vitro IC50 of 90 nM for chloroquine- and artemisinin-resistant lines, arresting asexual blood parasites at the trophozoite stage, as well as interfering with the development of both sexual and hepatic forms of Plasmodium. At its IC50, this compound is a powerful inhibitor of the aggregation of the model amyloid β peptide fragment 1-40, and it reduces the amount of aggregated proteins in P. falciparum cultures, suggesting that the underlying antimalarial mechanism consists in a generalized impairment of proteostasis in the pathogen. YAT2150 has an easy, rapid, and inexpensive synthesis, and because it fluoresces when it accumulates in its main localization in the Plasmodium cytosol, it is a theranostic agent. Conclusions Inhibiting protein aggregation in Plasmodium significantly reduces the parasite’s viability in vitro. Since YAT2150 belongs to a novel structural class of antiplasmodials with a mode of action that potentially targets multiple gene products, rapid evolution of resistance to this drug is unlikely to occur, making it a promising compound for the post-artemisinin era. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01374-4.
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Affiliation(s)
- Inés Bouzón-Arnáiz
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-University of Barcelona), Rosselló 149-153, 08036, Barcelona, Spain.,Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028, Barcelona, Spain.,Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain
| | - Yunuen Avalos-Padilla
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-University of Barcelona), Rosselló 149-153, 08036, Barcelona, Spain.,Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028, Barcelona, Spain.,Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain
| | - Arnau Biosca
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-University of Barcelona), Rosselló 149-153, 08036, Barcelona, Spain.,Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028, Barcelona, Spain.,Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain
| | - Omar Caño-Prades
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-University of Barcelona), Rosselló 149-153, 08036, Barcelona, Spain.,Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028, Barcelona, Spain.,Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain
| | - Lucía Román-Álamo
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-University of Barcelona), Rosselló 149-153, 08036, Barcelona, Spain.,Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028, Barcelona, Spain.,Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain
| | - Javier Valle
- Department of Medicine and Life Sciences, Barcelona Biomedical Research Park, Pompeu Fabra University, Dr. Aiguader 88, 08003, Barcelona, Spain
| | - David Andreu
- Department of Medicine and Life Sciences, Barcelona Biomedical Research Park, Pompeu Fabra University, Dr. Aiguader 88, 08003, Barcelona, Spain
| | - Diana Moita
- Instituto de Medicina Molecular, Fac. Medicina Univ. Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisbon, Portugal
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Fac. Medicina Univ. Lisboa, Av. Prof. Egas Moniz, 1649-028, Lisbon, Portugal
| | - Elsa M Arce
- Laboratory of Medicinal Chemistry (CSIC Associated Unit), Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
| | - Diego Muñoz-Torrero
- Laboratory of Medicinal Chemistry (CSIC Associated Unit), Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
| | - Xavier Fernàndez-Busquets
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-University of Barcelona), Rosselló 149-153, 08036, Barcelona, Spain. .,Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028, Barcelona, Spain. .,Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, 08028, Barcelona, Spain.
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22
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Comparison of entomological impacts of two methods of intervention designed to control Anopheles gambiae s.l. via swarm killing in Western Burkina Faso. Sci Rep 2022; 12:12397. [PMID: 35858978 PMCID: PMC9297277 DOI: 10.1038/s41598-022-16649-7] [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: 04/05/2022] [Accepted: 07/13/2022] [Indexed: 11/29/2022] Open
Abstract
Outdoor biting constitutes a major limitation of current vector control based primarily on long-lasting insecticidal nets and indoor residual spraying, both of which are indoor interventions. Consequently, malaria elimination will not be achieved unless additional tools are found to deal with the residual malaria transmission and the associated vector dynamics. In this study we tested a new vector control approach for rapidly crashing mosquito populations and disrupting malaria transmission in Africa. This method targets the previously neglected swarming and outdoor nocturnal behaviors of both male and female Anopheles mosquitoes. It involved accurate identification and targeted spraying of mosquito swarms to suppress adult malaria vector populations and their vectorial capacities. The impact of targeted spraying was compared to broadcast spraying and evaluated simultaneously. The effects of the two interventions were very similar, no significant differences between targeted spraying and broadcast spraying were found for effects on density, insemination or parity rate. However, targeted spraying was found to be significantly more effective than broadcast spraying at reducing the number of bites per person. As expected, each intervention had a highly significant impact upon all parameters measured, but the targeted swarm spraying required less insecticide.
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23
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Molina-Cruz A, Barillas-Mury C. Pfs47 as a Malaria Transmission-Blocking Vaccine Target. Am J Trop Med Hyg 2022; 107:tpmd211325. [PMID: 35895390 DOI: 10.4269/ajtmh.21-1325] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/06/2022] [Indexed: 02/18/2024] Open
Abstract
Transmission-blocking vaccines (TBVs), pioneered by Richard Carter and others, aim to prevent parasite development in the mosquito vector and are a promising new tool for malaria elimination. Pfs47, recently identified as a TBV target, is a three-domain 6-cysteine protein on the surface of Plasmodium falciparum sexual stages. Pfs47 allows the parasite to evade mosquito immunity and is key for P. falciparum infection of the dominant malaria vectors Anopheles gambiae, Anopheles dirus, and Anopheles albimanus. Antibodies against Pfs47 domain 2 (D2) have significant transmission-blocking activity that prevents Plasmodium ookinete development and is independent of human complement. Strong transmission-blocking activity has been mapped to a region of 52 amino acids in Pfs47 D2. Efforts to optimize the immunogenicity of the Pfs47 D2 antigen with a viral-like particle have been successful, and the efficacy of a P47-based TBV was confirmed in vivo with Pbs47, the orthologue of Pfs47 in the mouse malaria parasite Plasmodium berghei. The current evidence warrants further development and clinical testing of a Pfs47-based TBV.
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24
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Kimenyi KM, Wamae K, Ngoi JM, de Laurent ZR, Ndwiga L, Osoti V, Obiero G, Abdi AI, Bejon P, Ochola-Oyier LI. Maintenance of high temporal Plasmodium falciparum genetic diversity and complexity of infection in asymptomatic and symptomatic infections in Kilifi, Kenya from 2007 to 2018. Malar J 2022; 21:192. [PMID: 35725456 PMCID: PMC9207840 DOI: 10.1186/s12936-022-04213-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/03/2022] [Indexed: 11/30/2022] Open
Abstract
Background High levels of genetic diversity are common characteristics of Plasmodium falciparum parasite populations in high malaria transmission regions. There has been a decline in malaria transmission intensity over 12 years of surveillance in the community in Kilifi, Kenya. This study sought to investigate whether there was a corresponding reduction in P. falciparum genetic diversity, using msp2 as a genetic marker. Methods Blood samples were obtained from children (< 15 years) enrolled into a cohort with active weekly surveillance between 2007 and 2018 in Kilifi, Kenya. Asymptomatic infections were defined during the annual cross-sectional blood survey and the first-febrile malaria episode was detected during the weekly follow-up. Parasite DNA was extracted and successfully genotyped using allele-specific nested polymerase chain reactions for msp2 and capillary electrophoresis fragment analysis. Results Based on cross-sectional surveys conducted in 2007–2018, there was a significant reduction in malaria prevalence (16.2–5.5%: P-value < 0.001), however msp2 genetic diversity remained high. A high heterozygosity index (He) (> 0.95) was observed in both asymptomatic infections and febrile malaria over time. About 281 (68.5%) asymptomatic infections were polyclonal (> 2 variants per infection) compared to 46 (56%) polyclonal first-febrile infections. There was significant difference in complexity of infection (COI) between asymptomatic 2.3 [95% confidence interval (CI) 2.2–2.5] and febrile infections 2.0 (95% CI 1.7–2.3) (P = 0.016). Majority of asymptomatic infections (44.2%) carried mixed alleles (i.e., both FC27 and IC/3D7), while FC27 alleles were more frequent (53.3%) among the first-febrile infections. Conclusions Plasmodium falciparum infections in Kilifi are still highly diverse and polyclonal, despite the reduction in malaria transmission in the community. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04213-7.
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Affiliation(s)
- Kelvin M Kimenyi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya. .,Department of Biochemistry, University of Nairobi, Nairobi, Kenya.
| | - Kevin Wamae
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Joyce M Ngoi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,West Africa Centre for Cell Biology and Infectious Pathogen, Accra, Ghana
| | | | | | - Victor Osoti
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - George Obiero
- Department of Biochemistry, University of Nairobi, Nairobi, Kenya
| | | | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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25
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Abstract
"The Primate Malarias" book has been a uniquely important resource for multiple generations of scientists, since its debut in 1971, and remains pertinent to the present day. Indeed, nonhuman primates (NHPs) have been instrumental for major breakthroughs in basic and pre-clinical research on malaria for over 50 years. Research involving NHPs have provided critical insights and data that have been essential for malaria research on many parasite species, drugs, vaccines, pathogenesis, and transmission, leading to improved clinical care and advancing research goals for malaria control, elimination, and eradication. Whilst most malaria scientists over the decades have been studying Plasmodium falciparum, with NHP infections, in clinical studies with humans, or using in vitro culture or rodent model systems, others have been dedicated to advancing research on Plasmodium vivax, as well as on phylogenetically related simian species, including Plasmodium cynomolgi, Plasmodium coatneyi, and Plasmodium knowlesi. In-depth study of these four phylogenetically related species over the years has spawned the design of NHP longitudinal infection strategies for gathering information about ongoing infections, which can be related to human infections. These Plasmodium-NHP infection model systems are reviewed here, with emphasis on modern systems biological approaches to studying longitudinal infections, pathogenesis, immunity, and vaccines. Recent discoveries capitalizing on NHP longitudinal infections include an advanced understanding of chronic infections, relapses, anaemia, and immune memory. With quickly emerging new technological advances, more in-depth research and mechanistic discoveries can be anticipated on these and additional critical topics, including hypnozoite biology, antigenic variation, gametocyte transmission, bone marrow dysfunction, and loss of uninfected RBCs. New strategies and insights published by the Malaria Host-Pathogen Interaction Center (MaHPIC) are recapped here along with a vision that stresses the importance of educating future experts well trained in utilizing NHP infection model systems for the pursuit of innovative, effective interventions against malaria.
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Affiliation(s)
- Mary R Galinski
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA.
- Emory Vaccine Center, Emory University, Atlanta, GA, USA.
- Emory National Primate Research Center (Yerkes National Primate Research Center), Emory University, Atlanta, GA, USA.
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26
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Parihar RS, Bal PK, Saini A, Mishra SK, Thapliyal A. Potential future malaria transmission in Odisha due to climate change. Sci Rep 2022; 12:9048. [PMID: 35641573 PMCID: PMC9156684 DOI: 10.1038/s41598-022-13166-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/12/2022] [Indexed: 11/24/2022] Open
Abstract
Future projections of malaria transmission is made for Odisha, a highly endemic region of India, through numerical simulations using the VECTRI dynamical model. The model is forced with bias-corrected temperature and rainfall from a global climate model (CCSM4) for the baseline period 1975–2005 and for the projection periods 2020s, 2050s, and 2080s under RCP8.5 emission scenario. The temperature, rainfall, mosquito density and entomological inoculation rate (EIR), generated from the VECTRI model are evaluated with the observation and analyzed further to estimate the future malaria transmission over Odisha on a spatio-temporal scale owing to climate change. Our results reveal that the malaria transmission in Odisha as a whole during summer and winter monsoon seasons may decrease in future due to the climate change except in few districts with the high elevations and dense forest regions such as Kandhamal, Koraput, Raygada and Mayurbhanj districts where an increase in malaria transmission is found. Compared to the baseline period, mosquito density shows decrease in most districts of the south, southwest, central, north and northwest regions of Odisha in 2030s, 2050s and 2080s. An overall decrease in malaria transmission of 20–40% (reduction in EIR) is seen during the monsoon season (June-Sept) over Odisha with the increased surface temperature of 3.5–4 °C and with the increased rainfall of 20–35% by the end of the century with respect to the baseline period. Furthermore, malaria transmission is likely to reduce in future over most of the Odisha regions with the increase in future warm and cold nights temperatures.
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Affiliation(s)
- Ruchi Singh Parihar
- Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India.,Graphic Era Deemed to be University, Dehradun, Uttarakhand, India
| | | | - Atul Saini
- Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India.,Delhi School of Climate Change and Sustainability, Institution of Eminence, University of Delhi, Delhi, India
| | - Saroj Kanta Mishra
- Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Ashish Thapliyal
- Graphic Era Deemed to be University, Dehradun, Uttarakhand, India
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Dong Y, Sonawane Y, Maher SP, Zeeman AM, Chaumeau V, Vantaux A, Cooper CA, Chiu FCK, Ryan E, McLaren J, Chen G, Wittlin S, Witkowski B, Nosten F, Sriraghavan K, Kyle DE, Kocken CHM, Charman SA, Vennerstrom JL. Metabolic, Pharmacokinetic, and Activity Profile of the Liver Stage Antimalarial (RC-12). ACS OMEGA 2022; 7:12401-12411. [PMID: 35449901 PMCID: PMC9016807 DOI: 10.1021/acsomega.2c01099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
The catechol derivative RC-12 (WR 27653) (1) is one of the few non-8-aminoquinolines with good activity against hypnozoites in the gold-standard Plasmodium cynomolgi-rhesus monkey (Macaca mulatta) model, but in a small clinical trial, it had no efficacy against Plasmodium vivax hypnozoites. In an attempt to better understand the pharmacokinetic and pharmacodynamic profile of 1 and to identify potential active metabolites, we now describe the phase I metabolism, rat pharmacokinetics, and in vitro liver-stage activity of 1 and its metabolites. Compound 1 had a distinct metabolic profile in human vs monkey liver microsomes, and the data suggested that the O-desmethyl, combined O-desmethyl/N-desethyl, and N,N-didesethyl metabolites (or a combination thereof) could potentially account for the superior liver stage antimalarial efficacy of 1 in rhesus monkeys vs that seen in humans. Indeed, the rate of metabolism was considerably lower in human liver microsomes in comparison to rhesus monkey microsomes, as was the formation of the combined O-desmethyl/N-desethyl metabolite, which was the only metabolite tested that had any activity against liver-stage P. vivax; however, it was not consistently active against liver-stage P. cynomolgi. As 1 and all but one of its identified Phase I metabolites had no in vitro activity against P. vivax or P. cynomolgi liver-stage malaria parasites, we suggest that there may be additional unidentified active metabolites of 1 or that the exposure of 1 achieved in the reported unsuccessful clinical trial of this drug candidate was insufficient to kill the P. vivax hypnozoites.
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Affiliation(s)
- Yuxiang Dong
- College
of Pharmacy, University of Nebraska Medical
Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Yogesh Sonawane
- College
of Pharmacy, University of Nebraska Medical
Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Steven P. Maher
- Center
for Tropical and Emerging Global Diseases, University of Georgia, 370 Coverdell
Center, 500 D.W. Brooks Drive, Athens, Georgia 30602, United States
| | - Anne-Marie Zeeman
- Department
of Parasitology, Biomedical Primate Research
Centre, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| | - Victor Chaumeau
- Shoklo
Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit,
Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Road, Mae Sot, Tak 63110, Thailand
- Centre for
Tropical Medicine and Global Health, Nuffield Department of Medicine
Research building, University of Oxford
Old Road Campus, Oxford OX3 7DQ, U.K.
| | - Amélie Vantaux
- Malaria
Molecular Epidemiology Unit, Institut Pasteur
du Cambodge, 5 Boulevard Monivong, P.O. Box 983, Phnom
Penh 120 210, Cambodia
| | - Caitlin A. Cooper
- Center
for Tropical and Emerging Global Diseases, University of Georgia, 370 Coverdell
Center, 500 D.W. Brooks Drive, Athens, Georgia 30602, United States
| | - Francis C. K. Chiu
- Centre
for Drug Candidate Optimisation, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Eileen Ryan
- Centre
for Drug Candidate Optimisation, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Jenna McLaren
- Centre
for Drug Candidate Optimisation, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Gong Chen
- Centre
for Drug Candidate Optimisation, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Sergio Wittlin
- Department
of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4002 Basel, Switzerland
| | - Benoît Witkowski
- Malaria
Molecular Epidemiology Unit, Institut Pasteur
du Cambodge, 5 Boulevard Monivong, P.O. Box 983, Phnom
Penh 120 210, Cambodia
| | - François Nosten
- Shoklo
Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit,
Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Road, Mae Sot, Tak 63110, Thailand
- Centre for
Tropical Medicine and Global Health, Nuffield Department of Medicine
Research building, University of Oxford
Old Road Campus, Oxford OX3 7DQ, U.K.
| | - Kamaraj Sriraghavan
- College
of Pharmacy, University of Nebraska Medical
Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Dennis E. Kyle
- Center
for Tropical and Emerging Global Diseases, University of Georgia, 370 Coverdell
Center, 500 D.W. Brooks Drive, Athens, Georgia 30602, United States
| | - Clemens H. M. Kocken
- Department
of Parasitology, Biomedical Primate Research
Centre, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| | - Susan A. Charman
- Centre
for Drug Candidate Optimisation, Monash Institute of Pharmaceutical
Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Jonathan L. Vennerstrom
- College
of Pharmacy, University of Nebraska Medical
Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198, United States
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Dabira ED, Soumare HM, Conteh B, Ceesay F, Ndiath MO, Bradley J, Mohammed N, Kandeh B, Smit MR, Slater H, Peeters Grietens K, Broekhuizen H, Bousema T, Drakeley C, Lindsay SW, Achan J, D'Alessandro U. Mass drug administration of ivermectin and dihydroartemisinin-piperaquine against malaria in settings with high coverage of standard control interventions: a cluster-randomised controlled trial in The Gambia. THE LANCET. INFECTIOUS DISEASES 2022; 22:519-528. [PMID: 34919831 DOI: 10.1016/s1473-3099(21)00557-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 07/23/2021] [Accepted: 08/13/2021] [Indexed: 01/19/2023]
Abstract
BACKGROUND Although the malaria burden has substantially decreased in sub-Saharan Africa, progress has stalled. We assessed whether mass administration of ivermectin (a mosquitocidal drug) and dihydroartemisinin-piperaquine (an antimalarial treatment) reduces malaria in The Gambia, an area with high coverage of standard control interventions. METHODS This open-label, cluster-randomised controlled trial was done in the Upper River region of eastern Gambia. Villages with a baseline Plasmodium falciparum prevalence of 7-46% (all ages) and separated from each other by at least 3 km to reduce vector spillover were selected. Inclusion criteria were age and anthropometry (for ivermectin, weight of ≥15 kg; for dihydroartemisinin-piperaquine, participants older than 6 months); willingness to comply with trial procedures; and written informed consent. Villages were randomised (1:1) to either the intervention (ivermectin [orally at 300-400 μg/kg per day for 3 consecutive days] and dihydroartemisinin-piperaquine [orally depending on bodyweight] plus standard control interventions) or the control group (standard control interventions) using computer-based randomisation. Laboratory staff were masked to the origin of samples. In the intervention group, three rounds of mass drug administration once per month with ivermectin and dihydroartemisinin-piperaquine were given during two malaria transmission seasons from Aug 27 to Oct 31, 2018, and from July 15 to Sept 30, 2019. Primary outcomes were malaria prevalence by qPCR at the end of the second intervention year in November 2019, and Anopheles gambiae (s l) parous rate, analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT03576313. FINDINGS Between Nov 20 and Dec 7, 2017, 47 villages were screened for eligibility in the study. 15 were excluded because the baseline malaria prevalence was less than 7% (figure 1). 32 villages were enrolled and randomised to either the intervention or control group (n=16 in each group). The study population was 10 638, of which 4939 (46%) participants were in intervention villages. Coverage for dihydroartemisinin-piperaquine was between 49·0% and 58·4% in 2018, and between 76·1% and 86·0% in 2019; for ivermectin, coverage was between 46·9% and 52·2% in 2018, and between 71·7% and 82·9% in 2019. In November 2019, malaria prevalence was 12·8% (324 of 2529) in the control group and 5·1% (140 of 2722) in the intervention group (odds ratio [OR] 0·30, 95% CI 0·16-0·59; p<0·001). A gambiae (s l) parous rate was 83·1% (552 of 664) in the control group and 81·7% (441 of 540) in the intervention group (0·90, 0·66-1·25; p=0·537). In 2019, adverse events were recorded in 386 (9·7%) of 3991 participants in round one, 201 (5·4%) of 3750 in round two, and 168 (4·5%) of 3752 in round three. None of the 11 serious adverse events were related to the intervention. INTERPRETATION The intervention was safe and well tolerated. In an area with high coverage of standard control interventions, mass drug administration of ivermectin and dihydroartemisinin-piperaquine significantly reduced malaria prevalence; however, no effect of ivermectin on vector parous rate was observed. FUNDING Joint Global Health Trials Scheme. TRANSLATION For the French translation of the abstract see Supplementary Materials section.
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Affiliation(s)
- Edgard D Dabira
- Medical Research Council Unit, London School of Hygiene & Tropical Medicine, Fajara, The Gambia.
| | - Harouna M Soumare
- Medical Research Council Unit, London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - Bakary Conteh
- Medical Research Council Unit, London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - Fatima Ceesay
- Medical Research Council Unit, London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - Mamadou O Ndiath
- Medical Research Council Unit, London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - John Bradley
- London School of Hygiene & Tropical Medicine, London, UK
| | | | - Balla Kandeh
- National Malaria Control Program, Banjul, The Gambia
| | - Menno R Smit
- Amsterdam Centre for Global Child Health, Emma Children's Hospital, Amsterdam University Medical Centres, Amsterdam, Netherlands; Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Koen Peeters Grietens
- Department of Public Health, Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Henk Broekhuizen
- Department of Health and Society, Wageningen University, Wageningen, Netherlands; Department of Health Evidence, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Teun Bousema
- Radboud University Medical Centre, Nijmegen, Netherlands
| | - Chris Drakeley
- London School of Hygiene & Tropical Medicine, London, UK
| | | | - Jane Achan
- Medical Research Council Unit, London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit, London School of Hygiene & Tropical Medicine, Fajara, The Gambia
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Djidjou-Demasse R, Ducrot A, Mideo N, Texier G. Understanding dynamics of Plasmodium falciparum gametocytes production: Insights from an age-structured model. J Theor Biol 2022; 539:111056. [PMID: 35150720 DOI: 10.1016/j.jtbi.2022.111056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 02/01/2022] [Accepted: 02/04/2022] [Indexed: 11/16/2022]
Abstract
Many models of within-host malaria infection dynamics have been formulated since the pioneering work of Anderson et al. in 1989. Biologically, the goal of these models is to understand what governs the severity of infections, the patterns of infectiousness, and the variation thereof across individual hosts. Mathematically, these models are based on dynamical systems, with standard approaches ranging from K-compartments ordinary differential equations (ODEs) to delay differential equations (DDEs), to capture the relatively constant duration of replication and bursting once a parasite infects a host red blood cell. Using malariatherapy data, which offers fine-scale resolution on the dynamics of infection across a number of individual hosts, we compare the fit and robustness of one of these standard approaches (K-compartments ODE) with a partial differential equations (PDEs) model, which explicitly tracks the "age" of an infected cell. While both models perform quite similarly in terms of goodness-of-fit for suitably chosen K, the K-compartments ODE model particularly overestimates parasite densities early on in infections when the number of repeated compartments is not large enough. Finally, the K-compartments ODE model (for suitably chosen K) and the PDE model highlight a strong qualitative connection between the density of transmissible parasite stages (i.e., gametocytes) and the density of host-damaging (and asexually-replicating) parasite stages. This finding provides a simple tool for predicting which hosts are most infectious to mosquitoes -vectors of Plasmodium parasites- which is a crucial component of global efforts to control and eliminate malaria.
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Affiliation(s)
| | - Arnaud Ducrot
- Normandie Univ., UNIHAVRE, LMAH, FR-CNRS-3335 ISCN, 76600 Le Havre, France
| | - Nicole Mideo
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Gaëtan Texier
- Aix Marseille Univ., IRD, AP-HM, SSA, VITROME, IHU Méditerranée Infection, Marseille, France; Centre d'Epidémiologie et de Santé Publique des Armées (CESPA), Marseille, France
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Frasse PM, Miller JJ, Polino AJ, Soleimani E, Zhu JS, Jakeman DL, Jez JM, Goldberg DE, Odom John AR. Enzymatic and structural characterization of HAD5, an essential phosphomannomutase of malaria-causing parasites. J Biol Chem 2022; 298:101550. [PMID: 34973333 PMCID: PMC8808168 DOI: 10.1016/j.jbc.2021.101550] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 11/05/2022] Open
Abstract
The malaria-causing parasite Plasmodium falciparum is responsible for over 200 million infections and 400,000 deaths per year. At multiple stages during its complex life cycle, P. falciparum expresses several essential proteins tethered to its surface by glycosylphosphatidylinositol (GPI) anchors, which are critical for biological processes such as parasite egress and reinvasion of host red blood cells. Targeting this pathway therapeutically has the potential to broadly impact parasite development across several life stages. Here, we characterize an upstream component of parasite GPI anchor biosynthesis, the putative phosphomannomutase (PMM) (EC 5.4.2.8), HAD5 (PF3D7_1017400). We confirmed the PMM and phosphoglucomutase activities of purified recombinant HAD5 by developing novel linked enzyme biochemical assays. By regulating the expression of HAD5 in transgenic parasites with a TetR-DOZI-inducible knockdown system, we demonstrated that HAD5 is required for malaria parasite egress and erythrocyte reinvasion, and we assessed the role of HAD5 in GPI anchor synthesis by autoradiography of radiolabeled glucosamine and thin layer chromatography. Finally, we determined the three-dimensional X-ray crystal structure of HAD5 and identified a substrate analog that specifically inhibits HAD5 compared to orthologous human PMMs in a time-dependent manner. These findings demonstrate that the GPI anchor biosynthesis pathway is exceptionally sensitive to inhibition in parasites and that HAD5 has potential as a specific, multistage antimalarial target.
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Affiliation(s)
- Philip M Frasse
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Justin J Miller
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Alexander J Polino
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ebrahim Soleimani
- College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Chemistry, Razi University, Kermanshah, Iran
| | - Jian-She Zhu
- College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada
| | - David L Jakeman
- College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Joseph M Jez
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Audrey R Odom John
- Division of Infectious Diseases, Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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31
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Lee SH, Chu KB, Kang HJ, Quan FS. Protection and Alleviated Inflammation Induced by Virus-like Particle Vaccines Containing Plasmodium berghei MSP-8, MSP-9 and RAP1. Vaccines (Basel) 2022; 10:vaccines10020203. [PMID: 35214662 PMCID: PMC8875819 DOI: 10.3390/vaccines10020203] [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: 12/08/2021] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 12/03/2022] Open
Abstract
Virus-like particles (VLP) are a highly efficient vaccine platform used to present multiple antigenic proteins. Merozoite surface protein 8 (MSP-8), 9 (MSP-9) and rhoptry-associated protein 1 (RAP1) of Plasmodium berghei are the important proteins in erythrocyte invasion and the replication of parasites. In this study, we generated three VLPs expressing MSP-8, MSP-9 or RAP1 together with influenza virus matrix protein M1 as a core protein, and the protection and alleviated inflammation induced by VLP immunization were investigated. Mice were immunized with a mixture of three VLPs, MSP-8, MSP-9 and RAP1, and challenge-infected with P. berghei. As a result, VLPs immunization elicited higher levels of P. berghei or VLPs-specific IgG antibody responses in the sera upon boost compared to that upon prime and naive. Upon challenge infection with P. berghei, higher levels of CD4+ T cell and memory B cell responses in the spleen were also found in VLPs-immunized mice compared to non-immunized control. Importantly, VLP immunization significantly alleviated inflammatory cytokine responses (TNF-α, IFN-γ) both in the sera and spleen. VLP vaccine immunization also assisted in diminishing the parasitic burden in the peripheral blood and prolonged the survival of immunized mice. These results indicated that a VLPs vaccine containing MSP-8, MSP-9 and RAP1 could be a vaccine candidate for P. berghei infection.
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Affiliation(s)
- Su-Hwa Lee
- Department of Medical Zoology, School of Medicine, Kyung Hee University, Seoul 02447, Korea; (S.-H.L.); (K.-B.C.)
| | - Ki-Back Chu
- Department of Medical Zoology, School of Medicine, Kyung Hee University, Seoul 02447, Korea; (S.-H.L.); (K.-B.C.)
- Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea
| | - Hae-Ji Kang
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea;
| | - Fu-Shi Quan
- Department of Medical Zoology, School of Medicine, Kyung Hee University, Seoul 02447, Korea; (S.-H.L.); (K.-B.C.)
- Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea
- Correspondence: ; Tel.: +82-2-961-2302
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Abstract
Traditional and modern approaches have been applied to combat the malaria disease. Malaria eradication is a priority in several developing countries. Transmission-blocking vaccines are one of the suggested solutions for malaria eradication. Therefore, there is a demand for introducing the new targets and evaluation methods. Standard membrane feeding assay is the base of the evaluation process of transmission-blocking candidate molecules. Hence, this process is explained in this chapter in detail.
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Affiliation(s)
- Abbasali Raz
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran.
| | - Jafar J Sani
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Hemn Yousefi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
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Mugo RM, Mwai K, Mwacharo J, Shee FM, Musyoki JN, Wambua J, Otieno E, Bejon P, Ndungu FM. Seven-year kinetics of RTS, S/AS01-induced anti-CSP antibodies in young Kenyan children. Malar J 2021; 20:452. [PMID: 34856981 PMCID: PMC8641151 DOI: 10.1186/s12936-021-03961-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 10/20/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND RTS,S/AS01, the leading malaria vaccine has been recommended by the WHO for widespread immunization of children at risk. RTS,S/AS01-induced anti-CSP IgG antibodies are associated with the vaccine efficacy. Here, the long-term kinetics of RTS,S/AS01-induced antibodies was investigated. METHODS 150 participants were randomly selected from the 447 children who participated in the RTS,S/AS01 phase IIb clinical trial in 2007 from Kilifi-Kenya. Cumulatively, the retrospective follow-up period was 93 months with annual plasma samples collection. The levels of anti-CSP IgM, total IgG, IgG1, IgG2, IgG3, and IgG4 antibodies were then determined using an enzyme-linked immunosorbent assay. RESULTS RTS,S/AS01 induced high levels of anti-CSP IgG antibodies which exhibited a rapid waning over 6.5 months post-vaccination, followed by a slower decay over the subsequent years. RTS,S/AS01-induced anti-CSP IgG antibodies remained elevated above the control group levels throughout the 7 years follow-up period. The anti-CSP IgG antibodies were mostly IgG1, IgG3, IgG2, and to a lesser extent IgG4. IgG2 predominated in later timepoints. RTS,S/AS01 also induced high levels of anti-CSP IgM antibodies which increased above the control group levels by month 3. The controls exhibited increasing levels of the anti-CSP IgM antibodies which caught up with the RTS,S/AS01 vaccinees levels by month 21. In contrast, there were no measurable anti-CSP IgG antibodies among the controls. CONCLUSION RTS,S/AS01-induced anti-CSP IgG antibodies kinetics are consistent with long-lived but waning vaccine efficacy. Natural exposure induces anti-CSP IgM antibodies in children, which increases with age, but does not induce substantial levels of anti-CSP IgG antibodies.
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Affiliation(s)
- Robert M Mugo
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya.
- Institute of Immunology, Center for Infection Medicine, Freie Universtät Berlin, 14163, Berlin, Germany.
- Department of Biological Sciences, Pwani University, P.O. Box 195-80108, Kilifi, Kenya.
| | - Kennedy Mwai
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Jedidah Mwacharo
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Faiz M Shee
- Department of Biological Sciences, Pwani University, P.O. Box 195-80108, Kilifi, Kenya
| | - Jennifer N Musyoki
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Juliana Wambua
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Edward Otieno
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Francis M Ndungu
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya.
- Institute of Immunology, Center for Infection Medicine, Freie Universtät Berlin, 14163, Berlin, Germany.
- Department of Biological Sciences, Pwani University, P.O. Box 195-80108, Kilifi, Kenya.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
- Division of Infectious Diseases, Department of Medicine Solna and Centre for Molecular Medicine, Karolinska Institute, Stockholm, Sweden.
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Fink G, Venkataramani AS, Zanolini A. Early life adversity, biological adaptation, and human capital: evidence from an interrupted malaria control program in Zambia. JOURNAL OF HEALTH ECONOMICS 2021; 80:102532. [PMID: 34600186 DOI: 10.1016/j.jhealeco.2021.102532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/25/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
Growing evidence from evolutionary biology demonstrates how early life shocks trigger physiological changes designed to be adaptive in challenging environments. We examine the implications of one type of physiological adaptation - immunity formation - for human capital accumulation. Using variation in early life malaria risk generated by an interrupted disease control program in Zambia, we show that exposure to infectious diseases during the first two years of life can reduce the harmful effects of malaria exposure on cognitive development during the preschool years. These findings suggest a non-linear and trajectory-dependent relationship between early life adversity and human capital formation.
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Affiliation(s)
- Günther Fink
- Swiss Tropical and Public Health Institute and University of Basel, Basel, Switzerland.
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Keleta Y, Ramelow J, Cui L, Li J. Molecular interactions between parasite and mosquito during midgut invasion as targets to block malaria transmission. NPJ Vaccines 2021; 6:140. [PMID: 34845210 PMCID: PMC8630063 DOI: 10.1038/s41541-021-00401-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 11/01/2021] [Indexed: 11/21/2022] Open
Abstract
Despite considerable effort, malaria remains a major public health burden. Malaria is caused by five Plasmodium species and is transmitted to humans via the female Anopheles mosquito. The development of malaria vaccines against the liver and blood stages has been challenging. Therefore, malaria elimination strategies advocate integrated measures, including transmission-blocking approaches. Designing an effective transmission-blocking strategy relies on a sophisticated understanding of the molecular mechanisms governing the interactions between the mosquito midgut molecules and the malaria parasite. Here we review recent advances in the biology of malaria transmission, focusing on molecular interactions between Plasmodium and Anopheles mosquito midgut proteins. We provide an overview of parasite and mosquito proteins that are either targets for drugs currently in clinical trials or candidates of promising transmission-blocking vaccines.
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Affiliation(s)
- Yacob Keleta
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Julian Ramelow
- Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, USA
| | - Liwang Cui
- College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Jun Li
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA.
- Biomolecular Science Institute, Florida International University, Miami, FL, 33199, USA.
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Nateghpour M, Etemadi S, Motevalli Haghi A, Eslami H, Mohebali M, Farivar L. Serological responses to a soluble recombinant circumsporozoite protein-VK210 of Plasmodium vivax (rPvCSP-VK210) among Iranian malaria patients. Eur J Med Res 2021; 26:134. [PMID: 34823591 PMCID: PMC8620637 DOI: 10.1186/s40001-021-00607-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 11/14/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Circumsporozoite protein (CSP) has a central immune domain that includes short regions of repeating amino acid sequences. This immunodynamic region is an epitope of B cells that can elicit an immune response in human and laboratory animals. The aim of the present study was to express the recombinant PvCSP-VK210 antigen and evaluate it for assaying antibodies obtained during human P. vivax infection by Western blotting and indirect ELISA (enzyme-linked immunosorbent assay). METHOD Genomic DNA of P. vivax was isolated from a blood sample of an Iranian person with vivax malaria, and by PCR, the fragment of the PvCSP-VK210 gene was amplified. The gene fragment was cut after gel purification by BamHI and HindIII enzymes and then cloned into pET28a expression vector. Finally, the recombinant pET28a was transformed into the E. coli BL21 (DE3) as the expression host. In order to produce His-tagged protein, the expression host was cultured in LB medium. The protein was purified by Ni-NTA columns and immobilized metal affinity chromatography, and after confirmation by Western blotting technique, was used as the antigen in the indirect ELISA test. RESULTS The recombinant protein was expressed and purified as a 32-kDa protein. The sensitivity and specificity of the indirect ELISA test with the recombinant PvCSP-VK210 antigen were 61.42% and 97.14%, respectively, based on OD = 0.313. Between the results of the microscopic test and the indirect ELISA test with the recombinant PvCSP-VK210 antigen there was a Kappa coefficient of 0.586. The positive and negative predictive value and validity of the ELISA test with the recombinant PvCSP-VK210 antigen were 95.55%, 71.57%, 79.28%, respectively. CONCLUSION The sensitivity of the indirect ELISA method with the recombinant PvCSP-VK210 antigen was 61.42%, which is the first report from Iran.
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Affiliation(s)
- Mehdi Nateghpour
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Soudabeh Etemadi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. .,Infectious Disease and Tropical Medicine Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran. .,Department of Parasitology and Mycology, Faculty of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
| | - Afsaneh Motevalli Haghi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamid Eslami
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Mohebali
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Leila Farivar
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Carr AL, Rinker DC, Dong Y, Dimopoulos G, Zwiebel LJ. Transcriptome profiles of Anopheles gambiae harboring natural low-level Plasmodium infection reveal adaptive advantages for the mosquito. Sci Rep 2021; 11:22578. [PMID: 34799605 PMCID: PMC8604914 DOI: 10.1038/s41598-021-01842-x] [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: 09/06/2021] [Accepted: 11/03/2021] [Indexed: 11/09/2022] Open
Abstract
Anopheline mosquitoes are the sole vectors for the Plasmodium pathogens responsible for malaria, which is among the oldest and most devastating of human diseases. The continuing global impact of malaria reflects the evolutionary success of a complex vector-pathogen relationship that accordingly has been the long-term focus of both debate and study. An open question in the biology of malaria transmission is the impact of naturally occurring low-level Plasmodium infections of the vector on the mosquito’s health and longevity as well as critical behaviors such as host-preference/seeking. To begin to answer this, we have completed a comparative RNAseq-based transcriptome profile study examining the effect of biologically salient, salivary gland transmission-stage Plasmodium infection on the molecular physiology of Anopheles gambiae s.s. head, sensory appendages, and salivary glands. When compared with their uninfected counterparts, Plasmodium infected mosquitoes exhibit increased transcript abundance of genes associated with olfactory acuity as well as a range of synergistic processes that align with increased fitness based on both anti-aging and reproductive advantages. Taken together, these data argue against the long-held paradigm that malaria infection is pathogenic for anophelines and, instead suggests there are biological and evolutionary advantages for the mosquito that drive the preservation of its high vectorial capacity.
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Affiliation(s)
- Ann L Carr
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - David C Rinker
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA
| | - Yuemei Dong
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Laurence J Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA.
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Doolan DL. Malaria research in Australia: looking through the lens of the past towards the future. Int J Parasitol 2021; 51:1255-1263. [PMID: 34780720 DOI: 10.1016/j.ijpara.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 10/19/2022]
Abstract
Malaria remains a global health priority, with substantial resources devoted to control and intervention since the causative parasite was first identified in 1880. Major advances have been made in discovery and translational research activities aimed at prevention, treatment and control. Laboratory-based, clinical, and field-based studies have complemented public health approaches. Australian scientists have played important roles, developing and applying innovative approaches, novel research tools and cutting-edge technologies in animal and human models of disease, as well as in disease-endemic settings. This article will provide an insight into 50 years of Australian efforts to discover mechanisms and targets of immunity and pathogenesis; develop new diagnostics, drugs, vaccines, and therapeutics; and assess new public health interventions and control measures in malaria-endemic settings.
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Affiliation(s)
- Denise L Doolan
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health & Medicine, James Cook University, Cairns QLD 4878, Australia.
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Vythilingam I, Chua TH, Liew JWK, Manin BO, Ferguson HM. The vectors of Plasmodium knowlesi and other simian malarias Southeast Asia: challenges in malaria elimination. ADVANCES IN PARASITOLOGY 2021; 113:131-189. [PMID: 34620382 DOI: 10.1016/bs.apar.2021.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Plasmodium knowlesi, a simian malaria parasite of great public health concern has been reported from most countries in Southeast Asia and exported to various countries around the world. Currently P. knowlesi is the predominant species infecting humans in Malaysia. Besides this species, other simian malaria parasites such as P. cynomolgi and P. inui are also infecting humans in the region. The vectors of P. knowlesi and other Asian simian malarias belong to the Leucosphyrus Group of Anopheles mosquitoes which are generally forest dwelling species. Continual deforestation has resulted in these species moving into forest fringes, farms, plantations and human settlements along with their macaque hosts. Limited studies have shown that mosquito vectors are attracted to both humans and macaque hosts, preferring to bite outdoors and in the early part of the night. We here review the current status of simian malaria vectors and their parasites, knowledge of vector competence from experimental infections and discuss possible vector control measures. The challenges encountered in simian malaria elimination are also discussed. We highlight key knowledge gaps on vector distribution and ecology that may impede effective control strategies.
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Affiliation(s)
- Indra Vythilingam
- Department of Parasitology, University of Malaya, Kuala Lumpur, Malaysia.
| | - Tock Hing Chua
- Department of Pathobiology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Sabah Malaysia, Kota Kinabalu, Sabah, Malaysia.
| | - Jonathan Wee Kent Liew
- Department of Parasitology, University of Malaya, Kuala Lumpur, Malaysia; Environmental Health Institute, National Environment Agency, Singapore, Singapore
| | - Benny O Manin
- Department of Pathobiology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Sabah Malaysia, Kota Kinabalu, Sabah, Malaysia
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, United Kingdom
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Mwenda MC, Fola AA, Ciubotariu II, Mulube C, Mambwe B, Kasaro R, Hawela MB, Hamainza B, Miller JM, Carpi G, Bridges DJ. Performance evaluation of RDT, light microscopy, and PET-PCR for detecting Plasmodium falciparum malaria infections in the 2018 Zambia National Malaria Indicator Survey. Malar J 2021; 20:386. [PMID: 34583692 PMCID: PMC8477358 DOI: 10.1186/s12936-021-03917-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/14/2021] [Indexed: 11/29/2022] Open
Abstract
Background Zambia continues to advance on the path to elimination with significant reductions in malaria morbidity and mortality. Crucial components that have contributed to progress thus far and are necessary for achieving the national malaria elimination goals include properly identifying and treating all malaria cases through accurate diagnosis. This study sought to compare and assess the diagnostic performance of Rapid Diagnostic Tests (RDT) and Light Microscopy (LM) with photo-induced electron transfer polymerase chain reaction (PET-PCR) as the gold standard using 2018 Malaria Indicator Survey (MIS) data across Zambia to better understand diagnostic accuracy metrics and how these vary across a transmission gradient. Methods Cross-sectional samples collected in a nationally representative survey from 7 provinces in Zambia were tested for the presence of malaria parasites by light microscopy (LM), rapid diagnostic test (RDT) and the gold standard PET-PCR. Diagnostic performance was assessed including sensitivity, specificity, negative- and positive-predictive values across a wide malaria transmission spectrum. Diagnostic accuracy metrics were measured, and statistically significant differences were calculated between test methods for different outcome variables. Results From the individuals included in the MIS, the overall prevalence of Plasmodium falciparum malaria was 32.9% by RDT, 19.4% by LM, and 23.2% by PET-PCR. Herein, RDT and LM diagnostic performance was compared against gold standard PET-PCR with LM displaying a higher diagnostic accuracy than RDTs (91.3% vs. 84.6% respectively) across the transmission spectrum in Zambia. However, the performance of both diagnostics was significantly reduced in low parasitaemia samples. Consistent with previous studies, RDT diagnostic accuracy was predominantly affected by a high rate of false positives. Conclusions RDTs and LM both perform well across a range of transmission intensities within their respective target applications, i.e., in the community, for the former, where ease of use and speed of result is critical, and at the health facility, for the latter, where accuracy is prioritized. However, the performance of both diagnostic methods is adversely affected by low parasitaemia infections. As Zambia moves towards elimination more sensitive tools may be required to identify the last cases. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03917-6.
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Affiliation(s)
- Mulenga C Mwenda
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Abebe A Fola
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Ilinca I Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Conceptor Mulube
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Brenda Mambwe
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Rachael Kasaro
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Moonga B Hawela
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - Busiku Hamainza
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - John M Miller
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Giovanna Carpi
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Indiana, USA
| | - Daniel J Bridges
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia.
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Efforts Made to Eliminate Drug-Resistant Malaria and Its Challenges. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5539544. [PMID: 34497848 PMCID: PMC8421183 DOI: 10.1155/2021/5539544] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 08/09/2021] [Indexed: 01/01/2023]
Abstract
Since 2000, a good deal of progress has been made in malaria control. However, there is still an unacceptably high burden of the disease and numerous challenges limiting advancement towards its elimination and ultimate eradication. Among the challenges is the antimalarial drug resistance, which has been documented for almost all antimalarial drugs in current use. As a result, the malaria research community is working on the modification of existing treatments as well as the discovery and development of new drugs to counter the resistance challenges. To this effect, many products are in the pipeline and expected to be marketed soon. In addition to drug and vaccine development, mass drug administration (MDA) is under scientific scrutiny as an important strategy for effective utilization of the developed products. This review discusses the challenges related to malaria elimination, ongoing approaches to tackle the impact of drug-resistant malaria, and upcoming antimalarial drugs.
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Raghuwanshi AS, Kumar A, Raghuwanshi N, Singh SK, Singh AK, Tripathi U, Kaviraj S, Singh S. Development of a process for large scale production of PfRH5 in E. coli expression system. Int J Biol Macromol 2021; 188:169-179. [PMID: 34364940 DOI: 10.1016/j.ijbiomac.2021.08.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
The Plasmodium falciparum reticulocyte binding protein homologue 5 (PfRH5) has recently shown great promise to be developed as a vaccine candidate to prevent blood-stage malaria. However, because of its molecular complexity, most previous efforts were focused on expressing PfRH5 in its native and soluble form. Here, we describe the E. coli expression of full-length PfRH5 as inclusion bodies (IBs), followed by its high cell density fermentation at 1, 5 and 30 L scale. Denatured full-length PfRH5 was purified using a two-step chromatography process before being refolded using design of experiments (DoE). Refolded PfRH5 was further purified using size exclusion chromatography (SEC), recovering high purity antigen with an overall yield of 102 mg/L from fermentation cell harvest. Purified PfRH5 was further characterized using orthogonal analytical methods, and a short-term stability study revealed -80 °C as an optimum storage temperature. Moreover, refolded, and purified PfRH5, when formulated with adjuvant Glucopyranosyl A lipid stable emulsion (GLA-SE), elicited high antibody titers in BALB/c mice, proving its potential to neutralize the blood-stage malarial parasite. Here, we establish an E. coli-based process platform for the large-scale cGMP production of full-length PfRH5, enabling global malaria vaccine development efforts.
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Affiliation(s)
- Arjun Singh Raghuwanshi
- Vaccine Formulation and Research Center, Gennova Biopharmaceuticals Limited, Pune 411057, Maharashtra, India
| | - Ankit Kumar
- Vaccine Formulation and Research Center, Gennova Biopharmaceuticals Limited, Pune 411057, Maharashtra, India
| | - Navdeep Raghuwanshi
- Vaccine Formulation and Research Center, Gennova Biopharmaceuticals Limited, Pune 411057, Maharashtra, India
| | - Shravan Kumar Singh
- Vaccine Formulation and Research Center, Gennova Biopharmaceuticals Limited, Pune 411057, Maharashtra, India
| | - Avinash Kumar Singh
- Vaccine Formulation and Research Center, Gennova Biopharmaceuticals Limited, Pune 411057, Maharashtra, India
| | - Umanath Tripathi
- Vaccine Formulation and Research Center, Gennova Biopharmaceuticals Limited, Pune 411057, Maharashtra, India
| | - Swarnendu Kaviraj
- Vaccine Formulation and Research Center, Gennova Biopharmaceuticals Limited, Pune 411057, Maharashtra, India
| | - Sanjay Singh
- Vaccine Formulation and Research Center, Gennova Biopharmaceuticals Limited, Pune 411057, Maharashtra, India.
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Production and Immunogenicity of a Tag-Free Recombinant Chimera Based on PfMSP-1 and PfMSP-3 Using Alhydrogel and Dipeptide-Based Hydrogels. Vaccines (Basel) 2021; 9:vaccines9070782. [PMID: 34358198 PMCID: PMC8310097 DOI: 10.3390/vaccines9070782] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/23/2021] [Accepted: 05/26/2021] [Indexed: 12/13/2022] Open
Abstract
A fusion chimeric vaccine comprising multiple protective domains of different blood-stage Plasmodium falciparum antigens is perhaps necessary for widening the protective immune responses and reducing the morbidity caused by the disease. Here we continue to build upon the prior work of developing a recombinant fusion chimera protein, His-tagged PfMSP-Fu24, by producing it as a tag-free recombinant protein. In this study, tag-free recombinant PfMSPFu24 (rFu24) was expressed in Escherichia coli, and the soluble protein was purified using a three-step purification involving ammonium sulphate precipitation followed by 2-step ion exchange chromatography procedures and shown that it was highly immunogenic with the human-compatible adjuvant Alhydrogel. We further investigated two dipeptides, phenylalanine-α, β-dehydrophenylalanine (FΔF) and Leucine-α, β-dehydrophenylalanine (LΔF) based hydrogels as effective delivery platforms for rFu24. These dipeptides self-assembled spontaneously to form a highly stable hydrogel under physiological conditions. rFu24 was efficiently entrapped in both the F∆F and L∆F hydrogels, and the three-dimensional (3D) mesh-like structures of the hydrogels remained intact after the entrapment of the antigen. The two hydrogels significantly stimulated rFu24-specific antibody titers, and the sera from the immunized mice showed an invasion inhibitory activity comparable to that of Alhydrogel. Easily synthesized dipeptide hydrogels can be used as an effective antigen delivery platform to induce immune responses.
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Medjigbodo AA, Sonounameto EG, Djihinto OY, Abbey E, Salavi EB, Djossou L, Badolo A, Djogbénou LS. Interplay Between Oxytetracycline and the Homozygote kdr (L1014F) Resistance Genotype on Fecundity in Anopheles gambiae (Diptera: Culicidae) Mosquitoes. JOURNAL OF INSECT SCIENCE (ONLINE) 2021; 21:13. [PMID: 34379759 PMCID: PMC8356962 DOI: 10.1093/jisesa/ieab056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Indexed: 06/13/2023]
Abstract
The insecticide resistance in Anopheles gambiae mosquitoes has remained the major threat for vector control programs but the fitness effects conferred by these mechanisms are poorly understood. To fill this knowledge gap, the present study aimed at testing the hypothesis that antibiotic oxytetracycline could have an interaction with insecticide resistance genotypes and consequently inhibit the fecundity in An. gambiae. Four strains of An. gambiae: Kisumu (susceptible), KisKdr (kdr (L1014F) resistant), AcerKis (ace-1 (G119S) resistant) and AcerKdrKis (both kdr (L1014F) and ace-1 (G119S) resistant) were used in this study. The different strains were allowed to bloodfeed on a rabbit previously treated with antibiotic oxytetracycline at a concentration of 39·10-5 M. Three days later, ovarian follicles were dissected from individual mosquito ovaries into physiological saline solution (0.9% NaCl) under a stereomicroscope and the eggs were counted. Fecundity was substantially lower in oxytetracycline-exposed KisKdr females when compared to that of the untreated individuals and oxytetracycline-exposed Kisumu females. The exposed AcerKis females displayed an increased fecundity compared to their nontreated counterparts whereas they had reduced fecundity compared to that of oxytetracycline-exposed Kisumu females. There was no substantial difference between the fecundity in the treated and untreated AcerKdrKis females. The oxytetracycline-exposed AcerKdrKis mosquitoes had an increased fecundity compared to that of the exposed Kisumu females. Our data indicate an indirect effect of oxytetracycline in reducing fecundity of An. gambiae mosquitoes carrying kdrR (L1014F) genotype. These findings could be useful for designing new integrated approaches for malaria vector control in endemic countries.
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Affiliation(s)
- Adandé A Medjigbodo
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Fundamental and Applied Entomology, University Joseph KI-ZERBO, BP 7021, Ouagadougou 03, Burkina Faso, West Africa
| | - Eric G Sonounameto
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, 01BP 526, Cotonou, Benin
| | - Oswald Y Djihinto
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, 01BP 526, Cotonou, Benin
| | - Emmanuella Abbey
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, 01BP 526, Cotonou, Benin
| | - Esther B Salavi
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, 01BP 526, Cotonou, Benin
| | - Laurette Djossou
- Regional Institute of Public Health, University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Athanase Badolo
- Laboratory of Fundamental and Applied Entomology, University Joseph KI-ZERBO, BP 7021, Ouagadougou 03, Burkina Faso, West Africa
| | - Luc S Djogbénou
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Regional Institute of Public Health, University of Abomey-Calavi, BP 384, Ouidah, Benin
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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The Pan African Vivax and Ovale Network (PAVON): Refocusing on Plasmodium vivax, ovale and asymptomatic malaria in sub-Saharan Africa. Parasitol Int 2021; 84:102415. [PMID: 34216801 DOI: 10.1016/j.parint.2021.102415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 11/20/2022]
Abstract
The recent World Malaria report shows that progress in malaria elimination has stalled. Current data acquisition by NMCPs depend on passive case detection and clinical reports focused mainly on Plasmodium falciparum (Pf). In recent times, several countries in sub-Saharan Africa have reported cases of Plasmodium vivax (Pv) with a considerable number being Duffy negative. The burden of Pv and Plasmodium ovale (Po) appear to be more than acknowledged. Similarly, the contribution of asymptomatic malaria in transmission is hardly considered by NMCPs in Africa. Inclusion of these as targets in malaria elimination agenda is necessary to achieve elimination goal, as these harbor hypnozoites. The Pan African Vivax and Ovale Network (PAVON) is a new consortium of African Scientists working in Africa on the transmission profile of Pv and Po. The group collaborates with African NMCPs to train in Plasmodium molecular diagnostics, microscopy, and interpretation of molecular data from active surveys to translate into policy. Details of the mission, rational and modus operandi of the group are outlined.
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Okebe J, Dabira E, Jaiteh F, Mohammed N, Bradley J, Drammeh NF, Bah A, Masunaga Y, Achan J, Muela Ribera J, Yeung S, Balen J, Peeters Grietens K, D'Alessandro U. Reactive, self-administered malaria treatment against asymptomatic malaria infection: results of a cluster randomized controlled trial in The Gambia. Malar J 2021; 20:253. [PMID: 34098984 PMCID: PMC8186162 DOI: 10.1186/s12936-021-03761-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/11/2021] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Selectively targeting and treating malaria-infected individuals may further decrease parasite carriage in low-burden settings. Using a trans-disciplinary approach, a reactive treatment strategy to reduce Plasmodium falciparum prevalence in participating communities was co-developed and tested. METHODS This is a 2-arm, open-label, cluster-randomized trial involving villages in Central Gambia during the 2017 and 2018 malaria transmission season. Villages were randomized in a 1:1 ratio using a minimizing algorithm. In the intervention arm, trained village health workers delivered a full course of pre-packed dihydroartemisinin-piperaquine to all residents of compounds where clinical cases were reported while in the control arm, compound residents were screened for infection at the time of the index case reporting. All index cases were treated following national guidelines. The primary endpoint was malaria prevalence, determined by molecular methods, at the end of the intervention period. RESULTS The trial was carried out in 50 villages: 34 in 2017 and 16 additional villages in 2018. At the end of the 2018 transmission season, malaria prevalence was 0.8% (16/1924, range 0-4%) and 1.1% (20/1814, range 0-17%) in the intervention and control arms, respectively. The odds of malaria infection were 29% lower in the intervention than in the control arm after adjustment for age (OR 0.71, 95% CI 0.27-1.84, p = 0.48). Adherence to treatment was high, with 98% (964/979) of those treated completing the 3-day treatment. Over the course of the study, only 37 villages, 20 in the intervention and 17 in the control arm, reported at least one clinical case. The distribution of clinical cases by month in both transmission seasons was similar and the odds of new clinical malaria cases during the trial period did not vary between arms (OR 1.04, 95% CI 0.57-1.91, p = 0.893). All adverse events were classified as mild to moderate and resolved completely. CONCLUSION The systematic and timely administration of an anti-malarial treatment to residents of compounds with confirmed malaria cases did not significantly decrease malaria prevalence and incidence in communities where malaria prevalence was already low. Treatment coverage and adherence was very high. Results were strongly influenced by the lower-than-expected malaria prevalence, and by no clinical cases in villages with asymptomatic malaria-infected individuals. TRIAL REGISTRATION This study is registered with ClinicalTrials.gov, NCT02878200. Registered 25 August 2016. https://clinicaltrials.gov/ct2/show/NCT02878200 .
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Affiliation(s)
- Joseph Okebe
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Edgard Dabira
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Fatou Jaiteh
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
| | - Nuredin Mohammed
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Ndey-Fatou Drammeh
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Amadou Bah
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Yoriko Masunaga
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
| | - Jane Achan
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
- Malaria Consortium, Cambridge Heath, London, UK
| | | | - Shunmay Yeung
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Julie Balen
- School of Health and Related Research, The University of Sheffield, Sheffield, UK
| | | | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia.
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47
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Singh H, Sehrawat N. Molecular characterization and in-silico analysis of AsSGU (Secreted Glycocojugate of Unknown function) in malaria vector Anopheles stephensi for transmission blocking. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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48
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Monastyrskyi A, Brockmeyer F, LaCrue AN, Zhao Y, Maher SP, Maignan JR, Padin-Irizarry V, Sakhno YI, Parvatkar PT, Asakawa AH, Huang L, Casandra D, Mashkouri S, Kyle DE, Manetsch R. Aminoalkoxycarbonyloxymethyl Ether Prodrugs with a pH-Triggered Release Mechanism: A Case Study Improving the Solubility, Bioavailability, and Efficacy of Antimalarial 4(1 H)-Quinolones with Single Dose Cures. J Med Chem 2021; 64:6581-6595. [PMID: 33979164 DOI: 10.1021/acs.jmedchem.0c01104] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Preclinical and clinical development of numerous small molecules is prevented by their poor aqueous solubility, limited absorption, and oral bioavailability. Herein, we disclose a general prodrug approach that converts promising lead compounds into aminoalkoxycarbonyloxymethyl (amino AOCOM) ether-substituted analogues that display significantly improved aqueous solubility and enhanced oral bioavailability, restoring key requirements typical for drug candidate profiles. The prodrug is completely independent of biotransformations and animal-independent because it becomes an active compound via a pH-triggered intramolecular cyclization-elimination reaction. As a proof-of-concept, the utility of this novel amino AOCOM ether prodrug approach was demonstrated on an antimalarial compound series representing a variety of antimalarial 4(1H)-quinolones, which entered and failed preclinical development over the last decade. With the amino AOCOM ether prodrug moiety, the 3-aryl-4(1H)-quinolone preclinical candidate was shown to provide single-dose cures in a rodent malaria model at an oral dose of 3 mg/kg, without the use of an advanced formulation technique.
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Affiliation(s)
- Andrii Monastyrskyi
- Department of Chemistry, University of South Florida, CHE 205, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Fabian Brockmeyer
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, 102 Hurtig Hall, Boston, Massachusetts 02115, United States
| | - Alexis N LaCrue
- Department of Global Health, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, Florida 33612, United States
| | - Yingzhao Zhao
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, 102 Hurtig Hall, Boston, Massachusetts 02115, United States
| | - Steven P Maher
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Coverdell Center, Rm 370B, 500 DW Brooks Drive, Athens, Georgia 30602, United States
| | - Jordany R Maignan
- Department of Chemistry, University of South Florida, CHE 205, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Vivian Padin-Irizarry
- Department of Biology, Clayton State University, 2000 Clayton State Boulevard, Morrow, Georgia 30260, United States.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Coverdell Center, Rm 370B, 500 DW Brooks Drive, Athens, Georgia 30602, United States
| | - Yana I Sakhno
- Department of Chemistry, University of South Florida, CHE 205, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Prakash T Parvatkar
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, 102 Hurtig Hall, Boston, Massachusetts 02115, United States
| | - Ami H Asakawa
- Department of Pharmaceutical Sciences, Northeastern University, 102 Hurtig Hall, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Lili Huang
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, 102 Hurtig Hall, Boston, Massachusetts 02115, United States
| | - Debora Casandra
- Department of Global Health, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, Florida 33612, United States
| | - Sherwin Mashkouri
- Department of Global Health, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, Florida 33612, United States
| | - Dennis E Kyle
- Department of Global Health, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, Florida 33612, United States.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Coverdell Center, Rm 370B, 500 DW Brooks Drive, Athens, Georgia 30602, United States
| | - Roman Manetsch
- Department of Chemistry, University of South Florida, CHE 205, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States.,Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, 102 Hurtig Hall, Boston, Massachusetts 02115, United States.,Department of Pharmaceutical Sciences, Northeastern University, 102 Hurtig Hall, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
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49
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Immunofocusing humoral immunity potentiates the functional efficacy of the AnAPN1 malaria transmission-blocking vaccine antigen. NPJ Vaccines 2021; 6:49. [PMID: 33824336 PMCID: PMC8024329 DOI: 10.1038/s41541-021-00309-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/24/2021] [Indexed: 11/08/2022] Open
Abstract
Malaria transmission-blocking vaccines (TBVs) prevent the completion of the developmental lifecycle of malarial parasites within the mosquito vector, effectively blocking subsequent infections. The mosquito midgut protein Anopheline alanyl aminopeptidase N (AnAPN1) is the leading, mosquito-based TBV antigen. Structure-function studies identified two Class II epitopes that can induce potent transmission-blocking (T-B) antibodies, informing the design of the next-generation AnAPN1. Here, we functionally screened new immunogens and down-selected to the UF6b construct that has two glycine-linked copies of the T-B epitopes. We then established a process for manufacturing UF6b and evaluated in outbred female CD1 mice the immunogenicity of the preclinical product with the human-safe adjuvant Glucopyranosyl Lipid Adjuvant in a liposomal formulation with saponin QS21 (GLA-LSQ). UF6b:GLA-LSQ effectively immunofocused the humoral response to one of the key T-B epitopes resulting in potent T-B activity, underscoring UF6b as a prime TBV candidate to aid in malaria elimination and eradication efforts.
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50
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Bártolo I, Santos BS, Fontinha D, Machado M, Francisco D, Sepodes B, Rocha J, Mota-Filipe H, Pinto R, Figueira ME, Barroso H, Nascimento T, Alves de Matos AP, Alves AJS, Alves NG, Simões CJV, Prudêncio M, Pinho e Melo TMVD, Taveira N. Spiro-β-lactam BSS-730A Displays Potent Activity against HIV and Plasmodium. ACS Infect Dis 2021; 7:421-434. [PMID: 33395253 DOI: 10.1021/acsinfecdis.0c00768] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The high burden of malaria and HIV/AIDS prevents economic and social progress in developing countries. A continuing need exists for development of novel drugs and treatment regimens for both diseases in order to address the tolerability and long-term safety concerns associated with current treatment options and the emergence of drug resistance. We describe new spiro-β-lactam derivatives with potent (nM) activity against HIV and Plasmodium and no activity against bacteria and yeast. The best performing molecule of the series, BSS-730A, inhibited both HIV-1 and HIV-2 replication with an IC50 of 13 ± 9.59 nM and P. berghei hepatic infection with an IC50 of 0.55 ± 0.14 μM with a clear impact on parasite development. BSS-730A was also active against the erythrocytic stages of P. falciparum, with an estimated IC50 of 0.43 ± 0.04 μM. Time-of-addition studies showed that BSS-730A potentially affects all stages of the HIV replicative cycle, suggesting a complex mechanism of action. BSS-730A was active against multidrug-resistant HIV isolates, with a median 2.4-fold higher IC50 relative to control isolates. BSS-730A was equally active against R5 and X4 HIV isolates and displayed strong synergism with the entry inhibitor AMD3100. BSS-730A is a promising candidate for development as a potential therapeutic and/or prophylactic agent against HIV and Plasmodium.
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Affiliation(s)
- Inês Bártolo
- Instituto de investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal
| | - Bruna S. Santos
- Coimbra Chemistry Centre (CQC), Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Diana Fontinha
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1648-028 Lisboa, Portugal
| | - Marta Machado
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1648-028 Lisboa, Portugal
| | - Denise Francisco
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1648-028 Lisboa, Portugal
| | - Bruno Sepodes
- Instituto de investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal
| | - João Rocha
- Instituto de investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal
| | - Hélder Mota-Filipe
- Instituto de investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal
| | - Rui Pinto
- Instituto de investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal
| | - Maria E. Figueira
- Instituto de investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal
| | - Helena Barroso
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Universitário Egas Moniz, Quinta da Granja, 2829-511 Monte da Caparica, Portugal
| | - Teresa Nascimento
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Universitário Egas Moniz, Quinta da Granja, 2829-511 Monte da Caparica, Portugal
| | - António P. Alves de Matos
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Universitário Egas Moniz, Quinta da Granja, 2829-511 Monte da Caparica, Portugal
| | - Américo J. S. Alves
- Coimbra Chemistry Centre (CQC), Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Nuno G. Alves
- Coimbra Chemistry Centre (CQC), Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Carlos J. V. Simões
- Coimbra Chemistry Centre (CQC), Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Miguel Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1648-028 Lisboa, Portugal
| | | | - Nuno Taveira
- Instituto de investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Universitário Egas Moniz, Quinta da Granja, 2829-511 Monte da Caparica, Portugal
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