1
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Lindblom JR, Zhang X, Lehane AM. A pH Fingerprint Assay to Identify Inhibitors of Multiple Validated and Potential Antimalarial Drug Targets. ACS Infect Dis 2024; 10:1185-1200. [PMID: 38499199 PMCID: PMC11019546 DOI: 10.1021/acsinfecdis.3c00588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/22/2024] [Accepted: 02/09/2024] [Indexed: 03/20/2024]
Abstract
New drugs with novel modes of action are needed to safeguard malaria treatment. In recent years, millions of compounds have been tested for their ability to inhibit the growth of asexual blood-stage Plasmodium falciparum parasites, resulting in the identification of thousands of compounds with antiplasmodial activity. Determining the mechanisms of action of antiplasmodial compounds informs their further development, but remains challenging. A relatively high proportion of compounds identified as killing asexual blood-stage parasites show evidence of targeting the parasite's plasma membrane Na+-extruding, H+-importing pump, PfATP4. Inhibitors of PfATP4 give rise to characteristic changes in the parasite's internal [Na+] and pH. Here, we designed a "pH fingerprint" assay that robustly identifies PfATP4 inhibitors while simultaneously allowing the detection of (and discrimination between) inhibitors of the lactate:H+ transporter PfFNT, which is a validated antimalarial drug target, and the V-type H+ ATPase, which was suggested as a possible target of the clinical candidate ZY19489. In our pH fingerprint assays and subsequent secondary assays, ZY19489 did not show evidence for the inhibition of pH regulation by the V-type H+ ATPase, suggesting that it has a different mode of action in the parasite. The pH fingerprint assay also has the potential to identify protonophores, inhibitors of the acid-loading Cl- transporter(s) (for which the molecular identity(ies) remain elusive), and compounds that act through inhibition of either the glucose transporter PfHT or glycolysis. The pH fingerprint assay therefore provides an efficient starting point to match a proportion of antiplasmodial compounds with their mechanisms of action.
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Affiliation(s)
| | | | - Adele M. Lehane
- Research School of Biology, Australian National University, Canberra, Australian Capital
Territory 2600, Australia
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2
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Guo B, Borda V, Laboulaye R, Spring MD, Wojnarski M, Vesely BA, Silva JC, Waters NC, O'Connor TD, Takala-Harrison S. Strong positive selection biases identity-by-descent-based inferences of recent demography and population structure in Plasmodium falciparum. Nat Commun 2024; 15:2499. [PMID: 38509066 PMCID: PMC10954658 DOI: 10.1038/s41467-024-46659-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
Malaria genomic surveillance often estimates parasite genetic relatedness using metrics such as Identity-By-Decent (IBD), yet strong positive selection stemming from antimalarial drug resistance or other interventions may bias IBD-based estimates. In this study, we use simulations, a true IBD inference algorithm, and empirical data sets from different malaria transmission settings to investigate the extent of this bias and explore potential correction strategies. We analyze whole genome sequence data generated from 640 new and 3089 publicly available Plasmodium falciparum clinical isolates. We demonstrate that positive selection distorts IBD distributions, leading to underestimated effective population size and blurred population structure. Additionally, we discover that the removal of IBD peak regions partially restores the accuracy of IBD-based inferences, with this effect contingent on the population's background genetic relatedness and extent of inbreeding. Consequently, we advocate for selection correction for parasite populations undergoing strong, recent positive selection, particularly in high malaria transmission settings.
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Affiliation(s)
- Bing Guo
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Victor Borda
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Roland Laboulaye
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michele D Spring
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Mariusz Wojnarski
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Brian A Vesely
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (NOVA), Lisbon, Portugal
| | - Norman C Waters
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Timothy D O'Connor
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Shannon Takala-Harrison
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA.
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3
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Gogoi N, Rudrapal M, Celik I, Kaishap PP, Chetia D. In vitro and in silico guided identification of antimalarial phytoconstituent(s) in the root of Citrus maxima (Burm.) Merr. J Biomol Struct Dyn 2023:1-12. [PMID: 37975318 DOI: 10.1080/07391102.2023.2283154] [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: 05/16/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023]
Abstract
As a part of our continuous effort to find new therapeutic agents from natural sources, the hydroalcoholic (1:1) extract of Citrus maxima (Burm.) Merr. root was selected for the identification of possible antimalarial phytoconstituents. From the extract, three flavonoids including luteolin were isolated and evaluated for in vitro antimalarial activity against the chloroquine-sensitive (Pf3D7) and resistant (PfRKL-9) strains of Plasmodium falciparum. Among these, luteolin (CM3) showed the highest antimalarial activity with IC50 values of 2.315 ± 0.489 and 2.691 ± 0.454 µg/ml against the Pf3D7 and PfRKL-9 strains respectively. To assess the safety of luteolin (CM3), a cytotoxicity study against a normal human embryonic kidney cell line (HEK-293) was performed and the compound was found to be safe with a CC50 value of 222.3 ± 1.443 µg/ml. The docking study against 26 target proteins of P. falciparum revealed that luteolin (CM3) has a better binding affinity with two proteins, viz. P. falciparum lactate dehydrogenase (PfLDG) and P. falciparum enoyl-ACP reductase (PfEAR) in comparison to the co-crystallized ligands. Furthermore, the molecular dynamics simulation study of the protein-ligand complexes also supported the binding affinity and interactions of luteolin (CM3) at the active sites. Finally, the binding free energy calculation revealed that the luteolin formed a thermodynamically more stable complex with PfLDG (-50.955 ± 17.184 kJ/mol) than PfEAR (-24.856 ± 13.739 kJ/mol). Overall, in this study, we identified an antimalarial marker in the hydroalcoholic extract of C. maxima root which may act by inhibiting PfLDG.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Neelutpal Gogoi
- Department of Pharmaceutical Sciences, Faculty of Science and Engineering, Dibrugarh University, Dibrugarh, Assam, India
| | - Mithun Rudrapal
- Department of Pharmaceutical Sciences, School of Biotechnology and Pharmaceutical Sciences, Vignan's Foundation for Science, Technology & Research (Deemed to be University), Guntur, Andhra Pradesh, India
| | - Ismail Celik
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Erciyes University, Kayseri, Turkey
| | | | - Dipak Chetia
- Department of Pharmaceutical Sciences, Faculty of Science and Engineering, Dibrugarh University, Dibrugarh, Assam, India
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4
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Haldar K, Alam MS, Koepfli C, Lobo NF, Phru CS, Islam MN, Faiz A, Khan WA, Haque R. Bangladesh in the era of malaria elimination. Trends Parasitol 2023; 39:760-773. [PMID: 37500334 DOI: 10.1016/j.pt.2023.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 06/06/2023] [Accepted: 06/20/2023] [Indexed: 07/29/2023]
Abstract
Bangladesh has dramatically reduced malaria by 93% from 2008 to 2020. The strategy has been district-wise, phased elimination; however, the last districts targeted for elimination include remote, forested regions which present several challenges for prevention, detection, and treatment of malaria. These districts border Myanmar which harbors Plasmodium falciparum malaria parasites resistant to artemisinins, key drugs used in artemisinin-based combination therapies (ACTs) that have been vital for control programs. Challenges in monitoring emergence of artemisinin resistance (AR), tracking parasite reservoirs, changes in vector behavior and responses to insecticides, as well as other environmental and host factors (including the migration of Forcibly Displaced Myanmar Nationals; FDMNs) may pose added hazards in the final phase of eliminating malaria in Bangladesh.
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Affiliation(s)
- Kasturi Haldar
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, IN, USA; Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame, Indiana, IN, USA; Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, IN, USA.
| | - Mohammed Shafiul Alam
- Infectious Disease Division, International Center of Diarrheal Diseases, Bangladesh, (icddr, b), Dhaka, Bangladesh
| | - Cristian Koepfli
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, IN, USA; Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, IN, USA
| | - Neil F Lobo
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, IN, USA; Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, IN, USA
| | - Ching Shwe Phru
- Infectious Disease Division, International Center of Diarrheal Diseases, Bangladesh, (icddr, b), Dhaka, Bangladesh
| | | | - Abul Faiz
- Dev Care Foundation, Dhaka, Bangladesh
| | - Wasif Ali Khan
- Infectious Disease Division, International Center of Diarrheal Diseases, Bangladesh, (icddr, b), Dhaka, Bangladesh
| | - Rashidul Haque
- Infectious Disease Division, International Center of Diarrheal Diseases, Bangladesh, (icddr, b), Dhaka, Bangladesh
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5
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Guo B, Borda V, Laboulaye R, Spring MD, Wojnarski M, Vesely BA, Silva JC, Waters NC, O'Connor TD, Takala-Harrison S. Strong Positive Selection Biases Identity-By-Descent-Based Inferences of Recent Demography and Population Structure in Plasmodium falciparum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.14.549114. [PMID: 37502843 PMCID: PMC10370022 DOI: 10.1101/2023.07.14.549114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Malaria genomic surveillance often estimates parasite genetic relatedness using metrics such as Identity-By-Decent (IBD). Yet, strong positive selection stemming from antimalarial drug resistance or other interventions may bias IBD-based estimates. In this study, we utilized simulations, a true IBD inference algorithm, and empirical datasets from different malaria transmission settings to investigate the extent of such bias and explore potential correction strategies. We analyzed whole genome sequence data generated from 640 new and 4,026 publicly available Plasmodium falciparum clinical isolates. Our findings demonstrated that positive selection distorts IBD distributions, leading to underestimated effective population size and blurred population structure. Additionally, we discovered that the removal of IBD peak regions partially restored the accuracy of IBD-based inferences, with this effect contingent on the population's background genetic relatedness. Consequently, we advocate for selection correction for parasite populations undergoing strong, recent positive selection, particularly in high malaria transmission settings.
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Affiliation(s)
- Bing Guo
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD USA
| | - Victor Borda
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Roland Laboulaye
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michele D Spring
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Mariusz Wojnarski
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Brian A Vesely
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Norman C Waters
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Timothy D O'Connor
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shannon Takala-Harrison
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD USA
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6
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Chaorattanakawee S, Kosaisavee V, Bunsermyos W, Aonsri C, Imaram W, Suwannasin K, Kunasol C, Thamnurak C, Boonyalai N, Saunders D, Dondorp AM, Mungthin M, Imwong M. In vitro activity of rhinacanthin analogues against drug resistant Plasmodium falciparum isolates from Northeast Thailand. Malar J 2023; 22:105. [PMID: 36959593 PMCID: PMC10035203 DOI: 10.1186/s12936-023-04532-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/13/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND New anti-malarial drugs are needed urgently to address the increasing challenges of drug-resistant falciparum malaria. Two rhinacanthin analogues containing a naphthoquinone moiety resembling atovaquone showed promising in-vitro activity against a P. falciparum laboratory reference strain (K1). The anti-malarial activity of these 2 compounds was further evaluated for P. falciparum field isolates from an area of multi-drug resistance in Northeast Thailand. METHODS Using a pLDH enzyme-linked immunosorbent assay, four P. falciparum isolates from Northeast Thailand in 2018 were tested for in vitro sensitivity to the two synthetic rhinacanthin analogues 1 and 2 as well as established anti-malarials. Mutations in the P. falciparum cytochrome b gene, a marker for atovaquone (ATQ) resistance, were genotyped in all four field isolates as well as 100 other clinical isolates from the same area using PCR-artificial Restriction Fragment Length Polymorphisms. Pfkelch13 mutations, a marker for artemisinin (ART) resistance, were also examined in all isolates. RESULTS The 50% inhibitory concentrations (IC50) of P. falciparum field isolates for rhinacanthin analogue 1 was 321.9-791.1 nM (median = 403.1 nM). Parasites were more sensitive to analogue 2: IC50 48.6-63.3 nM (median = 52.2 nM). Similar results were obtained against P. falciparum reference laboratory strains 3D7 and W2. The ART-resistant IPC-5202 laboratory strain was more sensitive to these compounds with a median IC50 45.9 and 3.3 nM for rhinacanthin analogues 1 and 2, respectively. The ATQ-resistant C2B laboratory strain showed high-grade resistance towards both compounds (IC50 > 15,000 nM), and there was a strong positive correlation between the IC50 values for these compounds and ATQ (r = 0.83-0.97, P < 0.001). There were no P. falciparum cytochrome b mutations observed in the field isolates, indicating that P. falciparum isolates from this area remained ATQ-sensitive. Pfkelch13 mutations and the ring-stage survival assay confirmed that most isolates were resistant to ART. CONCLUSIONS Two rhinacanthin analogues showed parasiticidal activity against multi-drug resistant P. falciparum isolates, although less potent than ATQ. Rhinacanthin analogue 2 was more potent than analogue 1, and can be a lead compound for further optimization as an anti-malarial in areas with multidrug resistance.
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Affiliation(s)
- Suwanna Chaorattanakawee
- Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok, Thailand
| | - Varakorn Kosaisavee
- Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok, Thailand
| | - Watanyu Bunsermyos
- Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok, Thailand
| | - Chaiyawat Aonsri
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand
| | - Witcha Imaram
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Kanokon Suwannasin
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chanon Kunasol
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chatchadaporn Thamnurak
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Science (AFRIMS), Bangkok, Thailand
| | - Nonlawat Boonyalai
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Science (AFRIMS), Bangkok, Thailand
| | - David Saunders
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, 317 Ratchawithi Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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7
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Carrasquilla M, Drammeh NF, Rawat M, Sanderson T, Zenonos Z, Rayner JC, Lee MCS. Barcoding Genetically Distinct Plasmodium falciparum Strains for Comparative Assessment of Fitness and Antimalarial Drug Resistance. mBio 2022; 13:e0093722. [PMID: 35972144 PMCID: PMC9600763 DOI: 10.1128/mbio.00937-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 07/27/2022] [Indexed: 11/20/2022] Open
Abstract
The repeated emergence of antimalarial drug resistance in Plasmodium falciparum, including to the current frontline antimalarial artemisinin, is a perennial problem for malaria control. Next-generation sequencing has greatly accelerated the identification of polymorphisms in resistance-associated genes but has also highlighted the need for more sensitive and accurate laboratory tools to profile current and future antimalarials and to quantify the impact of drug resistance acquisition on parasite fitness. The interplay of fitness and drug response is of fundamental importance in understanding why particular genetic backgrounds are better at driving the evolution of drug resistance in natural populations, but the impact of parasite fitness landscapes on the epidemiology of drug resistance has typically been laborious to accurately quantify in the lab, with assays being limited in accuracy and throughput. Here we present a scalable method to profile fitness and drug response of genetically distinct P. falciparum strains with well-described sensitivities to several antimalarials. We leverage CRISPR/Cas9 genome-editing and barcode sequencing to track unique barcodes integrated into a nonessential gene (pfrh3). We validate this approach in multiplex competitive growth assays of three strains with distinct geographical origins. Furthermore, we demonstrate that this method can be a powerful approach for tracking artemisinin response as it can identify an artemisinin resistant strain within a mix of multiple parasite lines, suggesting an approach for scaling the laborious ring-stage survival assay across libraries of barcoded parasite lines. Overall, we present a novel high-throughput method for multiplexed competitive growth assays to evaluate parasite fitness and drug response. IMPORTANCE The complex interplay between antimalarial resistance and parasite fitness has important implications for understanding the development and spread of drug resistance alleles and the impact of genetic background on transmission. One limitation with current methodologies to measure parasite fitness is the ability to scale this beyond simple head-to-head competition experiments between a wildtype control line and test line, with a need for a scalable approach that allows tracking of parasite growth in complex mixtures. In our study, we have used CRISPR editing to insert unique DNA barcodes into a safe-harbor genomic locus to tag multiple parasite strains and use next-generation sequencing to read out strain dynamics. We observe inherent fitness differences between the strains, as well as sensitive modulation of responses to challenge with clinically relevant antimalarials, including artemisinin.
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Affiliation(s)
- Manuela Carrasquilla
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Max Planck Institute for Infection Biology, Berlin, Germany
| | - Ndey F. Drammeh
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Mukul Rawat
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Theo Sanderson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- The Francis Crick Institute, London, United Kingdom
| | - Zenon Zenonos
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Biologics Engineering, Early Oncology, AstraZeneca, Cambridge, United Kingdom
| | - Julian C. Rayner
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Marcus C. S. Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
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8
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Albarqouni L, Arab-Zozani M, Abukmail E, Greenwood H, Pathirana T, Clark J, Kopitowski K, Johansson M, Born K, Lang E, Moynihan R. Overdiagnosis and overuse of diagnostic and screening tests in low-income and middle-income countries: a scoping review. BMJ Glob Health 2022; 7:e008696. [PMID: 36316027 PMCID: PMC9442491 DOI: 10.1136/bmjgh-2022-008696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/12/2022] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE Overdiagnosis and overuse of healthcare services harm individuals, take resources that could be used to address underuse, and threaten the sustainability of health systems. These problems are attracting increasing attention in low-income and middle-income countries (LMICs). Unaware of any review of relevant evidence, we conducted a scoping review of the evidence around overdiagnosis and overuse of diagnostic and screening tests in LMICs. DESIGN Scoping review. METHODS We searched PubMed, Embase, PsycINFO, Global Index Medicus for relevant studies published until 24 May 2021, with no restrictions on date or language. We categorised included studies by major focus (overdiagnosis, overuse of tests, or both) and main themes (presence or estimates of extent; drivers; consequences and solutions). RESULTS We identified 2763 unique records and included 162 articles reporting on 154 studies across 55 countries, involving over 2.8 million participants and/or requests for tests. Almost half the studies focused on overdiagnosis (70; 45.5%), one-third on overuse of tests (61; 39.6%) and one-fifth on both (23; 14.9%). Common overdiagnosed conditions included malaria (61; 39.6%) and thyroid cancer (25; 16.2%), estimated to be >70% in China. Overused tests included imaging (n=25 studies) such as CT and MRI; laboratory investigations (n=18) such as serological tests and tumour markers; and procedures (n=14) such as colonoscopy. Drivers included fear of conflict with patients and expanding disease definitions. Common consequences included unnecessary treatments such as antimalarials, and wasted resources, with costs of malaria overdiagnosis estimated at US$86 million in Sudan in 1 year alone. Only 9% of studies discussed solutions, which included addressing inappropriately lowered diagnostic thresholds and reforming test-ordering processes. CONCLUSIONS Overdiagnosis and overuse of tests are widespread in LMICs and generate significant harm and waste. Better understanding of the problems and robust evaluation of solutions is needed, informed by a new global alliance of researchers and policy-makers.
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Affiliation(s)
- Loai Albarqouni
- Institute for Evidence-Based Healthcare (IEBH), Bond University, Gold Coast, Queensland, Australia
| | - Morteza Arab-Zozani
- Social Determinants of Health Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Eman Abukmail
- Institute for Evidence-Based Healthcare (IEBH), Bond University, Gold Coast, Queensland, Australia
| | - Hannah Greenwood
- Institute for Evidence-Based Healthcare (IEBH), Bond University, Gold Coast, Queensland, Australia
| | - Thanya Pathirana
- Institute for Evidence-Based Healthcare (IEBH), Bond University, Gold Coast, Queensland, Australia
- School of Medicine and Dentistry, Griffith University, Sunshine Coast, QLD, Australia
| | - Justin Clark
- Institute for Evidence-Based Healthcare (IEBH), Bond University, Gold Coast, Queensland, Australia
| | - Karin Kopitowski
- Directora Departamento de Investigación, Instituto Universitario Hospital Italiano, Argentina, Argentina
| | - Minna Johansson
- Department of Public Health and Community Medicine, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg University, Gothenburg, Sweden
- Cochrane Sustainable Healthcare, Uddevalla, Sweden
| | - Karen Born
- Department of Public Health and Community Medicine, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg University, Gothenburg, Sweden
| | - Eddy Lang
- Department of Emergency Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ray Moynihan
- Institute for Evidence-Based Healthcare (IEBH), Bond University, Gold Coast, Queensland, Australia
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9
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Pietarinen AV, Stanley DE. Precision medicine and diseases as natural kinds: An epistemological dilemma. J Eval Clin Pract 2022; 28:835-842. [PMID: 35644924 DOI: 10.1111/jep.13707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/29/2022] [Accepted: 05/15/2022] [Indexed: 01/01/2023]
Abstract
BACKGROUND The most important advance of precision medicine (PM) has been a specific way to define and understand disease. However, PM may fail to be therapeutically effective if diseases are natural kinds. OBJECTIVE To attest adverse consequences of treatments suggested by PM that do not generalize well. METHODS Conceptual analysis of PM; Epistemology of clinical reasoning; Cases that show diseases as natural kinds to clash with epistemology of PM. RESULTS Contemplation of future research options that could clarify the position of PM under the conception of diseases as natural kinds. CONCLUSION Need for improved design of future interventions that better acknowledge problematic epistemology of PM.
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Affiliation(s)
- Ahti-Veikko Pietarinen
- Ragnar Nurkse Department of Innovation and Governance, Tallinn University of Technology, Tallinn, Estonia
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10
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Qiu D, Pei JV, Rosling JEO, Thathy V, Li D, Xue Y, Tanner JD, Penington JS, Aw YTV, Aw JYH, Xu G, Tripathi AK, Gnadig NF, Yeo T, Fairhurst KJ, Stokes BH, Murithi JM, Kümpornsin K, Hasemer H, Dennis ASM, Ridgway MC, Schmitt EK, Straimer J, Papenfuss AT, Lee MCS, Corry B, Sinnis P, Fidock DA, van Dooren GG, Kirk K, Lehane AM. A G358S mutation in the Plasmodium falciparum Na + pump PfATP4 confers clinically-relevant resistance to cipargamin. Nat Commun 2022; 13:5746. [PMID: 36180431 PMCID: PMC9525273 DOI: 10.1038/s41467-022-33403-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 09/16/2022] [Indexed: 11/30/2022] Open
Abstract
Diverse compounds target the Plasmodium falciparum Na+ pump PfATP4, with cipargamin and (+)-SJ733 the most clinically-advanced. In a recent clinical trial for cipargamin, recrudescent parasites emerged, with most having a G358S mutation in PfATP4. Here, we show that PfATP4G358S parasites can withstand micromolar concentrations of cipargamin and (+)-SJ733, while remaining susceptible to antimalarials that do not target PfATP4. The G358S mutation in PfATP4, and the equivalent mutation in Toxoplasma gondii ATP4, decrease the sensitivity of ATP4 to inhibition by cipargamin and (+)-SJ733, thereby protecting parasites from disruption of Na+ regulation. The G358S mutation reduces the affinity of PfATP4 for Na+ and is associated with an increase in the parasite's resting cytosolic [Na+]. However, no defect in parasite growth or transmissibility is observed. Our findings suggest that PfATP4 inhibitors in clinical development should be tested against PfATP4G358S parasites, and that their combination with unrelated antimalarials may mitigate against resistance development.
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Affiliation(s)
- Deyun Qiu
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Jinxin V Pei
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - James E O Rosling
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Vandana Thathy
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Dongdi Li
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Yi Xue
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - John D Tanner
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Jocelyn Sietsma Penington
- Bioinformatic Division, The Walter & Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia
| | - Yi Tong Vincent Aw
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Jessica Yi Han Aw
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Guoyue Xu
- Department of Molecular Microbiology & Immunology and Johns Hopkins Malaria Institute, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
| | - Abhai K Tripathi
- Department of Molecular Microbiology & Immunology and Johns Hopkins Malaria Institute, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
| | - Nina F Gnadig
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Tomas Yeo
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Kate J Fairhurst
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Barbara H Stokes
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - James M Murithi
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | | | - Heath Hasemer
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Adelaide S M Dennis
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Melanie C Ridgway
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | | | - Judith Straimer
- Novartis Institute for Tropical Diseases, Emeryville, CA, 94608, USA
| | - Anthony T Papenfuss
- Bioinformatic Division, The Walter & Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Marcus C S Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
| | - Ben Corry
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Photini Sinnis
- Department of Molecular Microbiology & Immunology and Johns Hopkins Malaria Institute, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
| | - David A Fidock
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia.
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11
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Assessment of Plasmodium falciparum Artemisinin Resistance Independent of kelch13 Polymorphisms and with Escalating Malaria in Bangladesh. mBio 2022; 13:e0344421. [PMID: 35073756 PMCID: PMC8787467 DOI: 10.1128/mbio.03444-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Emerging resistance to artemisinin drugs threatens the elimination of malaria. Resistance is widespread in South East Asia (SEA) and Myanmar. Neighboring Bangladesh, where 90% of infections occur in the Chittagong Hill Tracts (CHTs), lacks recent assessment. We undertook a prospective study in the sole district-level hospital in Bandarban, a CHT district with low population densities but 60% of reported malaria cases. Thirty patients presented with malaria in 2018. An increase to 68 patients in 2019 correlated with the district-level rise in malaria, rainfall, humidity, and temperature. Twenty-four patients (7 in 2018 and 17 in 2019) with uncomplicated Plasmodium falciparum monoinfection were assessed for clearing parasites after starting artemisinin combination therapy (ACT). The median (range) time to clear half of the initial parasites was 5.6 (1.5 to 9.6) h, with 20% of patients showing a median of 8 h. There was no correlation between parasite clearance and initial parasitemia, blood cell counts, or mutations of P. falciparum gene Pfkelch13 (the molecular marker of artemisinin resistance [AR]). The in vitro ring-stage survival assay (RSA) revealed one (of four) culture-adapted strains with a quantifiable resistance of 2.01% ± 0.1% (mean ± standard error of the mean [SEM]). Regression analyses of in vivo and in vitro measurements of the four CHT strains and WHO-validated K13 resistance mutations yielded good correlation (R2 = 0.7; ρ = 0.9, P < 0.005), strengthening evaluation of emerging AR with small sample sizes, a challenge in many low/moderate-prevalence sites. There is an urgent need to deploy multiple, complementary approaches to understand the evolutionary dynamics of the emergence of P. falciparum resistant to artemisinin derivatives in countries where malaria is endemic. IMPORTANCE Malaria elimination is a Millennium Development Goal. Artemisinins, fast-acting antimalarial drugs, have played a key role in malaria elimination. Emergence of artemisinin resistance threatens the global elimination of malaria. Over the last decade, advanced clinical and laboratory methods have documented its spread throughout South East Asia and Myanmar. Neighboring Bangladesh lies in the historical path of dissemination of antimalarial resistance to the rest of the world, yet it has not been evaluated by combinations of leading methods, particularly in the highland Chittagong Hill Tracts adjacent to Myanmar which contain >90% of malaria in Bangladesh. We show the first establishment of capacity to assess clinical artemisinin resistance directly in patients in the hilltops and laboratory adaptation of Bangladeshi parasite strains from a remote, sparsely populated malaria frontier that is responsive to climate. Our study also provides a generalized model for comprehensive monitoring of drug resistance for countries where malaria is endemic.
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12
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A Phosphoinositide-Binding Protein Acts in the Trafficking Pathway of Hemoglobin in the Malaria Parasite Plasmodium falciparum. mBio 2022; 13:e0323921. [PMID: 35038916 PMCID: PMC8764524 DOI: 10.1128/mbio.03239-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Phosphoinositide lipids play key roles in a variety of processes in eukaryotic cells, but our understanding of their functions in the malaria parasite Plasmodium falciparum is still very much limited. To gain a deeper comprehension of the roles of phosphoinositides in this important pathogen, we attempted gene inactivation for 24 putative effectors of phosphoinositide metabolism. Our results reveal that 79% of the candidates are refractory to genetic deletion and are therefore potentially essential for parasite growth. Inactivation of the gene coding for a Plasmodium-specific putative phosphoinositide-binding protein, which we named PfPX1, results in a severe growth defect. We show that PfPX1 likely binds phosphatidylinositol-3-phosphate and that it localizes to the membrane of the digestive vacuole of the parasite and to vesicles filled with host cell cytosol and labeled with endocytic markers. Critically, we provide evidence that it is important in the trafficking pathway of hemoglobin from the host erythrocyte to the digestive vacuole. Finally, inactivation of PfPX1 renders parasites resistant to artemisinin, the frontline antimalarial drug. Globally, the minimal redundancy in the putative phosphoinositide proteins uncovered in our work supports that targeting this pathway has potential for antimalarial drug development. Moreover, our identification of a phosphoinositide-binding protein critical for the trafficking of hemoglobin provides key insight into this essential process. IMPORTANCE Malaria represents an enormous burden for a significant proportion of humanity, and the lack of vaccines and problems with drug resistance to all antimalarials demonstrate the need to develop new therapeutics. Inhibitors of phosphoinositide metabolism are currently being developed as antimalarials but our understanding of this biological pathway is incomplete. The malaria parasite lives inside human red blood cells where it imports hemoglobin to cover some of its nutritional needs. In this work, we have identified a phosphoinositide-binding protein that is important for the transport of hemoglobin in the parasite. Inactivation of this protein decreases the ability of the parasite to proliferate. Our results have therefore identified a potential new target for antimalarial development.
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13
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SheelaNair A, Romanczuk AS, Aogo RA, Haldar RN, Lansink LIM, Cromer D, Salinas YG, Guy RK, McCarthy JS, Davenport MP, Haque A, Khoury DS. Similarly efficacious anti-malarial drugs SJ733 and pyronaridine differ in their ability to remove circulating parasites in mice. Malar J 2022; 21:49. [PMID: 35172826 PMCID: PMC8848794 DOI: 10.1186/s12936-022-04075-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 02/06/2022] [Indexed: 11/13/2022] Open
Abstract
Background Artemisinin-based combination therapy (ACT) has been a mainstay for malaria prevention and treatment. However, emergence of drug resistance has incentivised development of new drugs. Defining the kinetics with which circulating parasitized red blood cells (pRBC) are lost after drug treatment, referred to as the “parasite clearance curve”, has been critical for assessing drug efficacy; yet underlying mechanisms remain partly unresolved. The clearance curve may be shaped both by the rate at which drugs kill parasites, and the rate at which drug-affected parasites are removed from circulation. Methods In this context, two anti-malarials, SJ733, and an ACT partner drug, pyronaridine were compared against sodium artesunate in mice infected with Plasmodium berghei (strain ANKA). To measure each compound’s capacity for pRBC removal in vivo, flow cytometric monitoring of a single cohort of fluorescently-labelled pRBC was employed, and combined with ex vivo parasite culture to assess parasite maturation and replication. Results These three compounds were found to be similarly efficacious in controlling established infection by reducing overall parasitaemia. While sodium artesunate acted relatively consistently across the life-stages, single-dose SJ733 elicited a biphasic effect, triggering rapid, partly phagocyte-dependent removal of trophozoites and schizonts, followed by arrest of residual ring-stages. In contrast, pyronaridine abrogated maturation of younger parasites, with less pronounced effects on mature parasites, while modestly increasing pRBC removal. Conclusions Anti-malarials SJ733 and pyronaridine, though similarly efficacious in reducing overall parasitaemia in mice, differed markedly in their capacity to arrest replication and remove pRBC from circulation. Thus, similar parasite clearance curves can result for anti-malarials with distinct capacities to inhibit, kill and clear parasites.
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Affiliation(s)
- Arya SheelaNair
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia
| | - Aleksandra S Romanczuk
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia
| | - Rosemary A Aogo
- Infection Analytics Program, Kirby Institute for Infection and Immunity, UNSW Sydney, Sydney, 2052, Australia
| | - Rohit Nemai Haldar
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia
| | - Lianne I M Lansink
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia.,Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, 792 Elizabeth Street, Parkville, VIC, 3000, Australia
| | - Deborah Cromer
- Infection Analytics Program, Kirby Institute for Infection and Immunity, UNSW Sydney, Sydney, 2052, Australia
| | | | - R Kiplin Guy
- College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia.,Department of Infectious Diseases, Peter Doherty Institute for Infection and Immunity, University of Melbourne, 792 Elizabeth Street, Parkville, VIC, 3000, Australia.,Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, VIC, 3000, Australia
| | - Miles P Davenport
- Infection Analytics Program, Kirby Institute for Infection and Immunity, UNSW Sydney, Sydney, 2052, Australia
| | - Ashraful Haque
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Brisbane, QLD, 4006, Australia. .,Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, 792 Elizabeth Street, Parkville, VIC, 3000, Australia.
| | - David S Khoury
- Infection Analytics Program, Kirby Institute for Infection and Immunity, UNSW Sydney, Sydney, 2052, Australia.
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14
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Anton L, Cobb DW, Ho CM. Structural parasitology of the malaria parasite Plasmodium falciparum. Trends Biochem Sci 2022; 47:149-159. [PMID: 34887149 PMCID: PMC11236216 DOI: 10.1016/j.tibs.2021.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 12/25/2022]
Abstract
The difficulty of faithfully recapitulating malarial protein complexes in heterologous expression systems has long impeded structural study for much of the Plasmodium falciparum proteome. However, recent advances in single-particle cryo electron microscopy (cryoEM) now enable structure determination at atomic resolution with significantly reduced requirements for both sample quantity and purity. Combined with recent developments in gene editing, these advances open the door to structure determination and structural proteomics of macromolecular complexes enriched directly from P. falciparum parasites. Furthermore, the combination of cryoEM with the rapidly emerging use of in situ cryo electron tomography (cryoET) to directly visualize ultrastructures and protein complexes in the native cellular context will yield exciting new insights into the molecular machinery underpinning malaria parasite biology and pathogenesis.
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Affiliation(s)
- Leonie Anton
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - David W Cobb
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Chi-Min Ho
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA.
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15
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Genetic Polymorphism and Natural Selection of Apical Membrane Antigen-1 in Plasmodium falciparum Isolates from Vietnam. Genes (Basel) 2021; 12:genes12121903. [PMID: 34946853 PMCID: PMC8701107 DOI: 10.3390/genes12121903] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/22/2021] [Accepted: 11/26/2021] [Indexed: 11/17/2022] Open
Abstract
Apical membrane antigen-1 of Plasmodium falciparum (PfAMA-1) is a leading malaria vaccine candidate antigen. However, the genetic diversity of pfama-1 and associated antigenic variation in global P. falciparum field isolates are major hurdles to the design of an efficacious vaccine formulated with this antigen. Here, we analyzed the genetic structure and the natural selection of pfama-1 in the P. falciparum population of Vietnam. A total of 37 distinct haplotypes were found in 131 P. falciparum Vietnamese isolates. Most amino acid changes detected in Vietnamese pfama-1 were localized in the ectodomain, domains I, II, and III. Overall patterns of major amino acid changes in Vietnamese pfama-1 were similar to those of global pfama-1, but the frequencies of the amino acid changes slightly differed by country. Novel amino acid changes were also identified in Vietnamese pfama-1. Vietnamese pfama-1 revealed relatively lower genetic diversity than currently analyzed pfama-1 in other geographical regions, and suggested a distinct genetic differentiation pattern. Evidence for natural selection was detected in Vietnamese pfama-1, but it showed purifying selection unlike the global pfama-1 analyzed so far. Recombination events were also found in Vietnamese pfama-1. Major amino acid changes that were commonly identified in global pfama-1 were mainly localized to predicted B-cell epitopes, RBC-binding sites, and IUR regions. These results provide important information for understanding the genetic nature of the Vietnamese pfama-1 population, and have significant implications for the design of a vaccine based on PfAMA-1.
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16
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Võ TC, Lê HG, Kang JM, Naw H, Fan CK, Trinh NTM, Quang HH, Na BK. Molecular surveillance of malaria in the Central Highlands, Vietnam. Parasitol Int 2021; 83:102374. [PMID: 33957296 DOI: 10.1016/j.parint.2021.102374] [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] [Received: 01/21/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 01/25/2023]
Abstract
Vietnam achieved outstanding success against malaria in the last few decades. The mortality and morbidity of malaria in Vietnam have decreased remarkably in recent years, but malaria is still a major public health concern in the country, particularly in the Central Highlands region. In this study, molecular analyses of malaria parasites in the Central Highlands were performed to understand the population structure and genetic diversity of the parasites circulating in the region. Plasmodium falciparum (68.7%) and P. vivax (27.4%) along with mixed infections with P. falciparum/P. vivax (3.9%) were detected in 230 blood samples from patients with malaria. Allele-specific nested-polymerase chain reaction (PCR) or PCR-restriction fragment length polymorphism (PCR-RFLP) analyses of pfmsp-1, pfama-1, pvcsp, and pvmsp-1 revealed complex genetic makeup in P. falciparum and P. vivax populations of Vietnam. Substantial multiplicity of infection (MOI) was also identified, suggesting significant genetic diversity and polymorphism of P. falciparum and P. vivax populations in the Central Highlands of Vietnam. These results provide fundamental insight into the current patterns of dispersion and genetic nature of malaria parasites as well as for the development of malaria elimination strategies in the endemic region.
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Affiliation(s)
- Tuấn Cường Võ
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
| | - Hương Giang Lê
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
| | - Haung Naw
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
| | - Chia-Kwung Fan
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine and Research Center of International Tropical Medicine, College of Medicine, Taipei Medical University, 250 Wu-Xing Street, Taipei, Taiwan.
| | - Nguyen Thi Minh Trinh
- Tropical Diseases Clinical and Treatment Research Department, Institute of Malariology, Parasitology, and Entomology Quy Nhon, MoH, 611B Nguyen Thai Hoc Street, Quy Nhon, Vietnam.
| | - Huynh Hong Quang
- Tropical Diseases Clinical and Treatment Research Department, Institute of Malariology, Parasitology, and Entomology Quy Nhon, MoH, 611B Nguyen Thai Hoc Street, Quy Nhon, Vietnam.
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Republic of Korea; Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Republic of Korea.
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17
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Duong MC, Pham OKN, Nguyen PT, Nguyen VVC, Nguyen PH. Predictors of treatment failures of plasmodium falciparum malaria in Vietnam: a 4-year single-centre retrospective study. Malar J 2021; 20:205. [PMID: 33926479 PMCID: PMC8082636 DOI: 10.1186/s12936-021-03720-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 04/01/2021] [Indexed: 11/10/2022] Open
Abstract
Background Drug-resistant falciparum malaria is an increasing public health burden. This study examined the magnitude of Plasmodium falciparum infection and the patterns and predictors of treatment failure in Vietnam. Methods Medical records of all 443 patients with malaria infection admitted to the Hospital for Tropical Diseases between January 2015 and December 2018 were used to extract information on demographics, risk factors, symptoms, laboratory tests, treatment, and outcome. Results More than half (59.8%, 265/443, CI 55.1–64.4%) of patients acquired Plasmodium falciparum infection of whom 21.9% (58/265, CI 17.1–27.4%) had severe malaria, while 7.2% (19/265, CI 4.6–10.9%) and 19.2% (51/265, CI 14.7–24.5%) developed early treatment failure (ETF) and late treatment failure (LTF) respectively. Among 58 patients with severe malaria, 14 (24.1%) acquired infection in regions where artemisinin resistance has been documented including Binh Phuoc (11 patients), Dak Nong (2 patients) and Gia Lai (1 patient). Under treatment with intravenous artesunate, the median (IQR) parasite half-life of 11 patients coming from Binh Phuoc was 3 h (2.3 to 8.3 h), two patients coming from Dak Nong was 2.8 and 5.7 h, and a patient coming from Gia Lai was 6.5 h. Most patients (98.5%, 261/265) recovered completely. Four patients with severe malaria died. Severe malaria was statistically associated with receiving treatment at previous hospitals (P < 0.001), hepatomegaly (P < 0.001) and number of inpatient days (P < 0.001). Having severe malaria was a predictor of ETF (AOR 6.96, CI 2.55–19.02, P < 0.001). No predictor of LTF was identified. Conclusions Plasmodium falciparum remains the prevalent malaria parasite. Despite low mortality rate, severe malaria is not rare and is a significant predictor of ETF. To reduce the risk for ETF, studies are needed to examine the effectiveness of combination therapy including parenteral artesunate and a parenteral partner drug for severe malaria. The study alerts the possibility of drug-resistant malaria in Africa and other areas in Vietnam, which are known as non-endemic areas of anti-malarial drug resistance. A more comprehensive study using molecular technique in these regions is required to completely understand the magnitude of drug-resistant malaria and to design appropriate control strategies.
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Affiliation(s)
- Minh Cuong Duong
- School of Population Health, University of New South Wales, Sydney, Australia
| | | | | | | | - Phu Hoan Nguyen
- Oxford University Clinical Research Unit (OUCRU), Ho Chi Minh City, Vietnam. .,Medical School, Vietnam National University of Ho Chi Minh City, Ho Chi Minh City, Vietnam.
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18
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Yamasaki N, Iwasaki I, Sakumi K, Hokari R, Ishiyama A, Iwatsuki M, Nakahara M, Higashibayashi S, Sugai T, Imagawa H, Kubo M, Fukuyama Y, Ōmura S, Yamamoto H. A Concise Total Synthesis of Dehydroantofine and Its Antimalarial Activity against Chloroquine-Resistant Plasmodium falciparum. Chemistry 2021; 27:5555-5563. [PMID: 33482050 DOI: 10.1002/chem.202100032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Indexed: 12/31/2022]
Abstract
The total synthesis of dehydroantofine was achieved by employing a novel, regioselective, azahetero Diels-Alder reaction of easily accessible 3,5-dichloro-2H-1,4-oxazin-2-one with 14 a as a key step. Furthermore, it is demonstrated that dehydroantofine is a promising candidate as a new antimalarial agent in a biological assay with chloroquine-resistant Plasmodium falciparum.
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Affiliation(s)
- Naoto Yamasaki
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 7708514, Japan
| | - Ikumi Iwasaki
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 7708514, Japan
| | - Kazu Sakumi
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 7708514, Japan
| | - Rei Hokari
- Ōmura Satoshi Memorial Institute and Graduate School of Infection, Control Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 1088641, Japan
| | - Aki Ishiyama
- Ōmura Satoshi Memorial Institute and Graduate School of Infection, Control Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 1088641, Japan
| | - Masato Iwatsuki
- Ōmura Satoshi Memorial Institute and Graduate School of Infection, Control Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 1088641, Japan
| | - Masataka Nakahara
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo, 1058512, Japan
| | - Shuhei Higashibayashi
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo, 1058512, Japan
| | - Takeshi Sugai
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo, 1058512, Japan
| | - Hiroshi Imagawa
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 7708514, Japan
| | - Miwa Kubo
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 7708514, Japan
| | - Yoshiyasu Fukuyama
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 7708514, Japan
| | - Satoshi Ōmura
- Ōmura Satoshi Memorial Institute and Graduate School of Infection, Control Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 1088641, Japan
| | - Hirofumi Yamamoto
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 7708514, Japan
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19
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Knaab TC, Held J, Burckhardt BB, Rubiano K, Okombo J, Yeo T, Mok S, Uhlemann AC, Lungerich B, Fischli C, Pessanha de Carvalho L, Mordmüller B, Wittlin S, Fidock DA, Kurz T. 3-Hydroxy-propanamidines, a New Class of Orally Active Antimalarials Targeting Plasmodium falciparum. J Med Chem 2021; 64:3035-3047. [PMID: 33666415 DOI: 10.1021/acs.jmedchem.0c01744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
3-Hydroxypropanamidines are a new promising class of highly active antiplasmodial agents. The most active compound 22 exhibited excellent antiplasmodial in vitro activity with nanomolar inhibition of chloroquine-sensitive and multidrug-resistant parasite strains ofPlasmodium falciparum (with IC50 values of 5 and 12 nM against 3D7 and Dd2 strains, respectively) as well as low cytotoxicity in human cells. In addition, 22 showed strong in vivo activity in thePlasmodium berghei mouse model with a cure rate of 66% at 50 mg/kg and a cure rate of 33% at 30 mg/kg in the Peters test after once daily oral administration for 4 consecutive days. A quick onset of action was indicated by the fast drug absorption shown in mice. The new lead compound was also characterized by a high barrier to resistance and inhibited the heme detoxification machinery in P. falciparum.
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Affiliation(s)
- Tanja C Knaab
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitaetsstraße 1, Düsseldorf 40225, Germany
| | - Jana Held
- Institute of Tropical Medicine, Eberhard Karls University Tübingen, Wilhelmstraße 27, Tübingen 72074, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné B.P.: 242, Gabon
| | - Bjoern B Burckhardt
- Institute of Clinical Pharmacy and Pharmacotherapy, Heinrich Heine University Düsseldorf, Universitaetsstraße 1, Düsseldorf 40225, Germany
| | - Kelly Rubiano
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York 10032, New York, United States
| | - John Okombo
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York 10032, New York, United States
| | - Tomas Yeo
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York 10032, New York, United States
| | - Sachel Mok
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York 10032, New York, United States
| | - Anne-Catrin Uhlemann
- Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York 10032, New York, United States
| | - Beate Lungerich
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitaetsstraße 1, Düsseldorf 40225, Germany
| | - Christoph Fischli
- Swiss Tropical and Public Health Institute, Socinstraße 57, Basel 4002, Switzerland.,University of Basel, Basel CH-4003, Switzerland
| | - Lais Pessanha de Carvalho
- Institute of Tropical Medicine, Eberhard Karls University Tübingen, Wilhelmstraße 27, Tübingen 72074, Germany
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, Eberhard Karls University Tübingen, Wilhelmstraße 27, Tübingen 72074, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné B.P.: 242, Gabon
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, Socinstraße 57, Basel 4002, Switzerland.,University of Basel, Basel CH-4003, Switzerland
| | - David A Fidock
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York 10032, New York, United States.,Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York 10032, New York, United States
| | - Thomas Kurz
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitaetsstraße 1, Düsseldorf 40225, Germany
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20
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Pereira PHS, Garcia CRS. Melatonin action in Plasmodium infection: Searching for molecules that modulate the asexual cycle as a strategy to impair the parasite cycle. J Pineal Res 2021; 70:e12700. [PMID: 33025644 PMCID: PMC7757246 DOI: 10.1111/jpi.12700] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 02/06/2023]
Abstract
Half of the world's population lives in countries at risk of malaria infection, which results in approximately 450,000 deaths annually. Malaria parasites infect erythrocytes in a coordinated manner, with cycle durations in multiples of 24 hours, which reflects a behavior consistent with the host's circadian cycle. Interference in cycle coordination can help the immune system to naturally fight infection. Consequently, there is a search for new drugs that interfere with the cycle duration for combined treatment with conventional antimalarials. Melatonin appears to be a key host hormone responsible for regulating circadian behavior in the parasite cycle. In addition to host factors, there are still unknown factors intrinsic to the parasite that control the cycle duration. In this review, we present a series of reports of indole compounds and melatonin derivatives with antimalarial activity that were tested on several species of Plasmodium to evaluate the cytotoxicity to parasites and human cells, in addition to the ability to interfere with the development of the erythrocytic cycle. Most of the reported compounds had an IC50 value in the low micromolar range, without any toxicity to human cells. Triptosil, an indole derivative of melatonin, was able to inhibit the effect of melatonin in vitro without causing changes to the parasitemia. The wide variety of tested compounds indicates that it is possible to develop a compound capable of safely eliminating parasites from the host and interfering with the life cycle, which is promising for the development of new combined therapies against malaria.
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Affiliation(s)
- Pedro H. S. Pereira
- Department of Clinical and Toxicological AnalysesSchool of Pharmaceutical SciencesUniversity of São PauloSão PauloBrazil
| | - Celia R. S. Garcia
- Department of Clinical and Toxicological AnalysesSchool of Pharmaceutical SciencesUniversity of São PauloSão PauloBrazil
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21
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Huang Z, Li R, Tang T, Ling D, Wang M, Xu D, Sun M, Zheng L, Zhu F, Min H, Boonhok R, Ding Y, Wen Y, Chen Y, Li X, Chen Y, Liu T, Han J, Miao J, Fang Q, Cao Y, Tang Y, Cui J, Xu W, Cui L, Zhu J, Wong G, Li J, Jiang L. A novel multistage antiplasmodial inhibitor targeting Plasmodium falciparum histone deacetylase 1. Cell Discov 2020; 6:93. [PMID: 33311461 PMCID: PMC7733455 DOI: 10.1038/s41421-020-00215-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 09/09/2020] [Indexed: 01/07/2023] Open
Abstract
Although artemisinin combination therapies have succeeded in reducing the global burden of malaria, multidrug resistance of the deadliest malaria parasite, Plasmodium falciparum, is emerging worldwide. Innovative antimalarial drugs that kill all life-cycle stages of malaria parasites are urgently needed. Here, we report the discovery of the compound JX21108 with broad antiplasmodial activity against multiple life-cycle stages of malaria parasites. JX21108 was developed from chemical optimization of quisinostat, a histone deacetylase inhibitor. We identified P. falciparum histone deacetylase 1 (PfHDAC1), an epigenetic regulator essential for parasite growth and invasion, as a molecular target of JX21108. PfHDAC1 knockdown leads to the downregulation of essential parasite genes, which is highly consistent with the transcriptomic changes induced by JX21108 treatment. Collectively, our data support that PfHDAC1 is a potential drug target for overcoming multidrug resistance and that JX21108 treats malaria and blocks parasite transmission simultaneously.
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Affiliation(s)
- Zhenghui Huang
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Ruoxi Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Tongke Tang
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Dazheng Ling
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Manjiong Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Dandan Xu
- Department of Microbiology and Parasitology, Bengbu Medical College, and Anhui Key Laboratory of Infection and Immunity, Bengbu, Anhui 233030, China
| | - Maoxin Sun
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Lulu Zheng
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Feng Zhu
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Hui Min
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Rachasak Boonhok
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Yan Ding
- Department of Pathogenic Biology, Army Medical University, Chongqing 400038, China
| | - Yuhao Wen
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yicong Chen
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaokang Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Yuxi Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110122, China
| | - Taiping Liu
- Department of Pathogenic Biology, Army Medical University, Chongqing 400038, China
| | - Jiping Han
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jun Miao
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Qiang Fang
- Department of Microbiology and Parasitology, Bengbu Medical College, and Anhui Key Laboratory of Infection and Immunity, Bengbu, Anhui 233030, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110122, China
| | - Yun Tang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Jie Cui
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wenyue Xu
- Department of Pathogenic Biology, Army Medical University, Chongqing 400038, China
| | - Liwang Cui
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Jin Zhu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China
| | - Gary Wong
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jian Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China.
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China.
| | - Lubin Jiang
- Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
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22
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Expansion of a Specific Plasmodium falciparum PfMDR1 Haplotype in Southeast Asia with Increased Substrate Transport. mBio 2020; 11:mBio.02093-20. [PMID: 33262257 PMCID: PMC7733942 DOI: 10.1128/mbio.02093-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Global efforts to eliminate malaria depend on the continued success of artemisinin-based combination therapies (ACTs) that target Plasmodium asexual blood-stage parasites. Resistance to ACTs, however, has emerged, creating the need to define the underlying mechanisms. Mutations in the P. falciparum multidrug resistance protein 1 (PfMDR1) transporter constitute an important determinant of resistance. Applying gene editing tools combined with an analysis of a public database containing thousands of parasite genomes, we show geographic selection and expansion of a pfmdr1 gene amplification encoding the N86/184F haplotype in Southeast Asia. Parasites expressing this PfMDR1 variant possess a higher transport capacity that modulates their responses to antimalarials. These data could help tailor and optimize antimalarial drug usage in different regions where malaria is endemic by taking into account the regional prevalence of pfmdr1 polymorphisms. Artemisinin-based combination therapies (ACTs) have been vital in reducing malaria mortality rates since the 2000s. Their efficacy, however, is threatened by the emergence and spread of artemisinin resistance in Southeast Asia. The Plasmodium falciparum multidrug resistance protein 1 (PfMDR1) transporter plays a central role in parasite resistance to ACT partner drugs through gene copy number variations (CNV) and/or single nucleotide polymorphisms (SNPs). Using genomic epidemiology, we show that multiple pfmdr1 copies encoding the N86 and 184F haplotype are prevalent across Southeast Asia. Applying genome editing tools on the Southeast Asian Dd2 strain and using a surrogate assay to measure transporter activity in infected red blood cells, we demonstrate that parasites harboring multicopy N86/184F PfMDR1 have a higher Fluo-4 transport capacity compared with those expressing the wild-type N86/Y184 haplotype. Multicopy N86/184F PfMDR1 is also associated with decreased parasite susceptibility to lumefantrine. These findings provide evidence of the geographic selection and expansion of specific multicopy PfMDR1 haplotypes associated with multidrug resistance in Southeast Asia.
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23
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Clark RL. Teratogen update: Malaria in pregnancy and the use of antimalarial drugs in the first trimester. Birth Defects Res 2020; 112:1403-1449. [PMID: 33079495 DOI: 10.1002/bdr2.1798] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 02/04/2023]
Abstract
Malaria is a particular problem in pregnancy because of enhanced sensitivity, the possibility of placental malaria, and adverse effects on pregnancy outcome. Artemisinin-containing combination therapies (ACTs) are the most effective antimalarials known. WHO recommends 7-day quinine therapy for uncomplicated Plasmodium falciparum malaria in the first trimester despite the superior tolerability and efficacy of 3-day ACT regimens because artemisinins caused embryolethality and/or cardiovascular malformations at relatively low doses in rats, rabbits, and monkeys. The developmental toxicity of artesunate, artemether, and DHA were similar in rats but artesunate was embryotoxic at lower doses in rabbits (5 mg/kg/day) than artemether (no effect level = 25 mg/kg/day). In clinical studies in Africa, treatment with artemether-lumefantrine in the first trimester was observed to be highly efficacious and the miscarriage rate (≤3.1%) was similar to no antimalarial treatment (2.6%). When data from the first-trimester use of largely artesunate-based therapies in Thailand were pooled together, there was no difference in miscarriage rate compared to quinine. However, individually, artesunate-mefloquine was associated with a higher miscarriage rate (15/71 = 21%) compared to other artemisinin-based therapies including 7-day artesunate + clindamycin (2/50 = 4%) and quinine (92/842 = 11%). Thus, appropriate statistical comparisons of individual ACT groups are needed prior to assuming that they all have the same risk for developmental toxicity. Current limitations in the assessment of the safety of ACTs in the first trimester are a lack of exposures early in gestation (gestational weeks 6-7), limited postnatal evaluation for cardiovascular malformations, and the pooling of all ACTs for the assessment of risk.
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Affiliation(s)
- Robert L Clark
- Artemis Pharmaceutical Research, Saint Augustine, Florida, USA
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