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Small-Saunders JL, Hagenah LM, Wicht KJ, Dhingra SK, Deni I, Kim J, Vendome J, Gil-Iturbe E, Roepe PD, Mehta M, Mancia F, Quick M, Eppstein MJ, Fidock DA. Evidence for the early emergence of piperaquine-resistant Plasmodium falciparum malaria and modeling strategies to mitigate resistance. PLoS Pathog 2022; 18:e1010278. [PMID: 35130315 PMCID: PMC8853508 DOI: 10.1371/journal.ppat.1010278] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 02/17/2022] [Accepted: 01/13/2022] [Indexed: 11/19/2022] Open
Abstract
Multidrug-resistant Plasmodium falciparum parasites have emerged in Cambodia and neighboring countries in Southeast Asia, compromising the efficacy of first-line antimalarial combinations. Dihydroartemisinin + piperaquine (PPQ) treatment failure rates have risen to as high as 50% in some areas in this region. For PPQ, resistance is driven primarily by a series of mutant alleles of the P. falciparum chloroquine resistance transporter (PfCRT). PPQ resistance was reported in China three decades earlier, but the molecular driver remained unknown. Herein, we identify a PPQ-resistant pfcrt allele (China C) from Yunnan Province, China, whose genotypic lineage is distinct from the PPQ-resistant pfcrt alleles currently observed in Cambodia. Combining gene editing and competitive growth assays, we report that PfCRT China C confers moderate PPQ resistance while re-sensitizing parasites to chloroquine (CQ) and incurring a fitness cost that manifests as a reduced rate of parasite growth. PPQ transport assays using purified PfCRT isoforms, combined with molecular dynamics simulations, highlight differences in drug transport kinetics and in this transporter’s central cavity conformation between China C and the current Southeast Asian PPQ-resistant isoforms. We also report a novel computational model that incorporates empirically determined fitness landscapes at varying drug concentrations, combined with antimalarial susceptibility profiles, mutation rates, and drug pharmacokinetics. Our simulations with PPQ-resistant or -sensitive parasite lines predict that a three-day regimen of PPQ combined with CQ can effectively clear infections and prevent the evolution of PfCRT variants. This work suggests that including CQ in combination therapies could be effective in suppressing the evolution of PfCRT-mediated multidrug resistance in regions where PPQ has lost efficacy. The recent emergence of Plasmodium falciparum parasite resistance to the antimalarial drug piperaquine (PPQ) has contributed to frequent treatment failures across Southeast Asia, originating in Cambodia. Here, we show that earlier reports of PPQ resistance in Yunnan Province, China could be explained by the unique China C variant of the P. falciparum chloroquine resistance transporter PfCRT. Gene-edited parasites show a loss of fitness and parasite resensitization to the chemically related former first-line antimalarial chloroquine, while acquiring PPQ resistance via drug efflux. Molecular features of drug resistance were examined using biochemical assays to measure mutant PfCRT-mediated drug transport and molecular dynamics simulations with the recently solved PfCRT structure to assess changes in the central drug-binding cavity. We also describe a new computational model that incorporates parasite mutation rates, fitness costs, antimalarial susceptibilities, and drug pharmacological profiles to predict how infections with parasite strains expressing distinct PfCRT variants can evolve and be selected in response to different drug pressures and regimens. Simulations predict that a three-day regimen of PPQ plus chloroquine would be fully effective at preventing recrudescence of drug-resistant infections.
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Affiliation(s)
- Jennifer L Small-Saunders
- Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Laura M Hagenah
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Kathryn J Wicht
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Satish K Dhingra
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Ioanna Deni
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Jonathan Kim
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, New York United States of America
| | - Jeremie Vendome
- Schrödinger, Inc., New York, New York, United States of America
| | - Eva Gil-Iturbe
- Department of Psychiatry, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Paul D Roepe
- Department of Chemistry, Georgetown University, Washington, DC, United States of America
- Department of Biochemistry and Cellular and Molecular Biology, Georgetown University, Washington, DC, United States of America
| | - Monica Mehta
- Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, New York United States of America
| | - Matthias Quick
- Department of Psychiatry, Columbia University Irving Medical Center, New York, New York, United States of America
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, United States of America
- Center for Molecular Recognition, Columbia University Irving Medical Center, New York, New York, United States of America
| | - Margaret J Eppstein
- Vermont Complex Systems Center, University of Vermont, Burlington, Vermont, United States of America
- Department of Computer Science, University of Vermont, Burlington, Vermont, United States of America
- Translational Global Infectious Diseases Research Center, University of Vermont, Burlington, Vermont, United States of America
| | - David A Fidock
- Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, New York, United States of America
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York, United States of America
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Endo T, Takemae H, Sharma I, Furuya T. Multipurpose Drugs Active Against Both Plasmodium spp. and Microorganisms: Potential Application for New Drug Development. Front Cell Infect Microbiol 2021; 11:797509. [PMID: 35004357 PMCID: PMC8740689 DOI: 10.3389/fcimb.2021.797509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/01/2021] [Indexed: 12/29/2022] Open
Abstract
Malaria, a disease caused by the protozoan parasites Plasmodium spp., is still causing serious problems in endemic regions in the world. Although the WHO recommends artemisinin combination therapies for the treatment of malaria patients, the emergence of artemisinin-resistant parasites has become a serious issue and underscores the need for the development of new antimalarial drugs. On the other hand, new and re-emergences of infectious diseases, such as the influenza pandemic, Ebola virus disease, and COVID-19, are urging the world to develop effective chemotherapeutic agents against the causative viruses, which are not achieved to the desired level yet. In this review article, we describe existing drugs which are active against both Plasmodium spp. and microorganisms including viruses, bacteria, and fungi. We also focus on the current knowledge about the mechanism of actions of these drugs. Our major aims of this article are to describe examples of drugs that kill both Plasmodium parasites and other microbes and to provide valuable information to help find new ideas for developing novel drugs, rather than merely augmenting already existing drug repurposing efforts.
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Affiliation(s)
- Takuro Endo
- Laboratory of Veterinary Infectious Diseases, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Hitoshi Takemae
- Center for Infectious Disease Epidemiology and Prevention Research, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Indu Sharma
- Department of Biological Sciences, Hampton University, Hampton, VA, United States
| | - Tetsuya Furuya
- Laboratory of Veterinary Infectious Diseases, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
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3
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Abstract
Almost 20 years have passed since the first reference genome assemblies were published for Plasmodium falciparum, the deadliest malaria parasite, and Anopheles gambiae, the most important mosquito vector of malaria in sub-Saharan Africa. Reference genomes now exist for all human malaria parasites and nearly half of the ~40 important vectors around the world. As a foundation for genetic diversity studies, these reference genomes have helped advance our understanding of basic disease biology and drug and insecticide resistance, and have informed vaccine development efforts. Population genomic data are increasingly being used to guide our understanding of malaria epidemiology, for example by assessing connectivity between populations and the efficacy of parasite and vector interventions. The potential value of these applications to malaria control strategies, together with the increasing diversity of genomic data types and contexts in which data are being generated, raise both opportunities and challenges in the field. This Review discusses advances in malaria genomics and explores how population genomic data could be harnessed to further support global disease control efforts.
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Affiliation(s)
- Daniel E Neafsey
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA, USA.
| | - Aimee R Taylor
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Bronwyn L MacInnis
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA, USA.
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4
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Gabryszewski SJ, Modchang C, Musset L, Chookajorn T, Fidock DA. Combinatorial Genetic Modeling of pfcrt-Mediated Drug Resistance Evolution in Plasmodium falciparum. Mol Biol Evol 2016; 33:1554-70. [PMID: 26908582 PMCID: PMC4868112 DOI: 10.1093/molbev/msw037] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The emergence of drug resistance continuously threatens global control of infectious diseases, including malaria caused by the protozoan parasite Plasmodium falciparum. A critical parasite determinant is the P. falciparum chloroquine resistance transporter (PfCRT), the primary mediator of chloroquine (CQ) resistance (CQR), and a pleiotropic modulator of susceptibility to several first-line artemisinin-based combination therapy partner drugs. Aside from the validated CQR molecular marker K76T, P. falciparum parasites have acquired at least three additional pfcrt mutations, whose contributions to resistance and fitness have been heretofore unclear. Focusing on the quadruple-mutant Ecuadorian PfCRT haplotype Ecu1110 (K76T/A220S/N326D/I356L), we genetically modified the pfcrt locus of isogenic, asexual blood stage P. falciparum parasites using zinc-finger nucleases, producing all possible combinations of intermediate pfcrt alleles. Our analysis included the related quintuple-mutant PfCRT haplotype 7G8 (Ecu1110 + C72S) that is widespread throughout South America and the Western Pacific. Drug susceptibilities and in vitro growth profiles of our combinatorial pfcrt-modified parasites were used to simulate the mutational trajectories accessible to parasites as they evolved CQR. Our results uncover unique contributions to parasite drug resistance and growth for mutations beyond K76T and predict critical roles for the CQ metabolite monodesethyl-CQ and the related quinoline-type drug amodiaquine in driving mutant pfcrt evolution. Modeling outputs further highlight the influence of parasite proliferation rates alongside gains in drug resistance in dictating successful trajectories. Our findings suggest that P. falciparum parasites have navigated constrained pfcrt adaptive landscapes by means of probabilistically rare mutational bursts that led to the infrequent emergence of pfcrt alleles in the field.
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Affiliation(s)
| | - Charin Modchang
- Department of Physics, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Lise Musset
- Laboratoire de Parasitologie, WHO Collaborating Center for Surveillance of Anti-Malarial Drug Resistance, Institut Pasteur de la Guyane, Cayenne, French Guiana
| | - Thanat Chookajorn
- Genomics and Evolutionary Medicine Unit, Center of Excellence in Malaria, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY
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5
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Read AF, Huijben S. Evolutionary biology and the avoidance of antimicrobial resistance. Evol Appl 2015; 2:40-51. [PMID: 25567846 PMCID: PMC3352414 DOI: 10.1111/j.1752-4571.2008.00066.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 12/11/2008] [Indexed: 11/29/2022] Open
Abstract
Evolutionary biologists have largely left the search for solutions to the drug resistance crisis to biomedical scientists, physicians, veterinarians and public health specialists. We believe this is because the vast majority of professional evolutionary biologists consider the evolutionary science of drug resistance to be conceptually uninteresting. Using malaria as case study, we argue that it is not. We review examples of evolutionary thinking that challenge various fallacies dominating antimalarial therapy, and discuss open problems that need evolutionary insight. These problems are unlikely to be resolved by biomedical scientists ungrounded in evolutionary biology. Involvement by evolutionary biologists in the science of drug resistance requires no intellectual compromises: the problems are as conceptually challenging as they are important.
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Affiliation(s)
- Andrew F Read
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park PA, USA
| | - Silvie Huijben
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park PA, USA ; School of Biological Sciences, University of Edinburgh West Mains Road, Edinburgh, UK
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6
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Wanka L, Iqbal K, Schreiner PR. The lipophilic bullet hits the targets: medicinal chemistry of adamantane derivatives. Chem Rev 2013; 113:3516-604. [PMID: 23432396 PMCID: PMC3650105 DOI: 10.1021/cr100264t] [Citation(s) in RCA: 441] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Lukas Wanka
- Institute of Organic Chemistry, Justus-Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany; Fax +49(641)9934309
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314-6399, USA
| | - Khalid Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314-6399, USA
| | - Peter R. Schreiner
- Institute of Organic Chemistry, Justus-Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany; Fax +49(641)9934309
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7
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Shahinas D, Folefoc A, Pillai DR. Targeting Plasmodium falciparum Hsp90: Towards Reversing Antimalarial Resistance. Pathogens 2013; 2:33-54. [PMID: 25436880 PMCID: PMC4235713 DOI: 10.3390/pathogens2010033] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 01/18/2013] [Accepted: 01/23/2013] [Indexed: 12/29/2022] Open
Abstract
Malaria continues to exact a great human toll in tropical settings. Antimalarial resistance is rife and the parasite inexorably develops mechanisms to outwit our best drugs, including the now first-line choice, artesunate. Novel strategies to circumvent resistance are needed. Here we detail drug development focusing on heat shock protein 90 and its central role as a chaperone. A growing body of evidence supports the role for Hsp90 inhibitors as adjunctive drugs able to restore susceptibility to traditionally efficacious compounds like chloroquine.
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Affiliation(s)
- Dea Shahinas
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Canada.
| | - Asongna Folefoc
- Department of Pathology & Laboratory Medicine, The University of Calgary, Calgary, AB, Canada.
| | - Dylan R Pillai
- Department of Pathology & Laboratory Medicine, The University of Calgary, Calgary, AB, Canada.
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8
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Gbotosho GO, Folarin OA, Bustamante C, da Silva LHP, Mesquita E, Sowunmi A, Zalis MG, Oduola AMJ, Happi CT. Different patterns of pfcrt and pfmdr1 polymorphisms in P. falciparum isolates from Nigeria and Brazil: the potential role of antimalarial drug selection pressure. Am J Trop Med Hyg 2012; 86:211-3. [PMID: 22302850 DOI: 10.4269/ajtmh.2012.11-0368] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The effect of antimalarial drug selection on pfcrt and pfmdr1 polymorphisms in Plasmodium falciparum isolates from two distinct geographical locations was determined in 70 and 18 P. falciparum isolates from Nigeria and Brazil, respectively, using nested polymerase chain reaction and direct DNA sequencing approaches. All isolates from Brazil and 72% from Nigeria harbored the mutant SVMNT and CVIET pfcrt haplotype, respectively. The pfcrt CVMNT haplotype was also observed in (7%) of the Nigerian samples. One hundred percent (100%) and 54% of the parasites from Brazil and Nigeria, respectively, harbored wild-type pfmdr1Asn86. We provide first evidence of emergence of the CVMNT haplotype in West Africa. The high prevalence of pfcrt CVIET and SVMNT haplotypes in Nigeria and Brazil, respectively, is indicative of different selective pressure by chloroquine and amodiaquine. Continuous monitoring of pfcrt SVMNT haplotype is required in endemic areas of Africa, where artesunate-amodiaquine combination is used for treatment of acute uncomplicated malaria.
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Affiliation(s)
- Grace O Gbotosho
- Malaria Research Laboratories, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria.
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9
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Yuan J, Cheng KCC, Johnson RL, Huang R, Pattaradilokrat S, Liu A, Guha R, Fidock D, Inglese J, Wellems TE, Austin CP, Su XZ. Chemical genomic profiling for antimalarial therapies, response signatures, and molecular targets. Science 2011; 333:724-9. [PMID: 21817045 PMCID: PMC3396183 DOI: 10.1126/science.1205216] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Malaria remains a devastating disease largely because of widespread drug resistance. New drugs and a better understanding of the mechanisms of drug action and resistance are essential for fulfilling the promise of eradicating malaria. Using high-throughput chemical screening and genome-wide association analysis, we identified 32 highly active compounds and genetic loci associated with differential chemical phenotypes (DCPs), defined as greater than or equal to fivefold differences in half-maximum inhibitor concentration (IC(50)) between parasite lines. Chromosomal loci associated with 49 DCPs were confirmed by linkage analysis and tests of genetically modified parasites, including three genes that were linked to 96% of the DCPs. Drugs whose responses mapped to wild-type or mutant pfcrt alleles were tested in combination in vitro and in vivo, which yielded promising new leads for antimalarial treatments.
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Affiliation(s)
- Jing Yuan
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases
| | - Ken Chih-Chien Cheng
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Ronald L. Johnson
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Ruili Huang
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Anna Liu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases
| | - Rajarshi Guha
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - David Fidock
- Departments of Microbiology and Immunology and of Medicine, Columbia University Medical Center, New York, New York, USA
| | - James Inglese
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Thomas E. Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases
| | - Christopher P. Austin
- NIH Chemical Genomics Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Xin-zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases
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10
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Mok S, Imwong M, Mackinnon MJ, Sim J, Ramadoss R, Yi P, Mayxay M, Chotivanich K, Liong KY, Russell B, Socheat D, Newton PN, Day NPJ, White NJ, Preiser PR, Nosten F, Dondorp AM, Bozdech Z. Artemisinin resistance in Plasmodium falciparum is associated with an altered temporal pattern of transcription. BMC Genomics 2011; 12:391. [PMID: 21810278 PMCID: PMC3163569 DOI: 10.1186/1471-2164-12-391] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 08/03/2011] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Artemisinin resistance in Plasmodium falciparum malaria has emerged in Western Cambodia. This is a major threat to global plans to control and eliminate malaria as the artemisinins are a key component of antimalarial treatment throughout the world. To identify key features associated with the delayed parasite clearance phenotype, we employed DNA microarrays to profile the physiological gene expression pattern of the resistant isolates. RESULTS In the ring and trophozoite stages, we observed reduced expression of many basic metabolic and cellular pathways which suggests a slower growth and maturation of these parasites during the first half of the asexual intraerythrocytic developmental cycle (IDC). In the schizont stage, there is an increased expression of essentially all functionalities associated with protein metabolism which indicates the prolonged and thus increased capacity of protein synthesis during the second half of the resistant parasite IDC. This modulation of the P. falciparum intraerythrocytic transcriptome may result from differential expression of regulatory proteins such as transcription factors or chromatin remodeling associated proteins. In addition, there is a unique and uniform copy number variation pattern in the Cambodian parasites which may represent an underlying genetic background that contributes to the resistance phenotype. CONCLUSIONS The decreased metabolic activities in the ring stages are consistent with previous suggestions of higher resilience of the early developmental stages to artemisinin. Moreover, the increased capacity of protein synthesis and protein turnover in the schizont stage may contribute to artemisinin resistance by counteracting the protein damage caused by the oxidative stress and/or protein alkylation effect of this drug. This study reports the first global transcriptional survey of artemisinin resistant parasites and provides insight to the complexities of the molecular basis of pathogens with drug resistance phenotypes in vivo.
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Affiliation(s)
- Sachel Mok
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Thailand
- Mahidol-Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | | | - Joan Sim
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Ramya Ramadoss
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Poravuth Yi
- The National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Mayfong Mayxay
- Wellcome Trust-Mahosot Hospital-Oxford University Tropical Medicine Research Collaboration, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Faculty of Postgraduate Studies and Research, University of Health Sciences, Vientiane, Lao People's Democratic Republic
| | - Kesinee Chotivanich
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Kek-Yee Liong
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Bruce Russell
- Singapore Immunology Network, Biopolis, Agency for Science Technology and Research (ASTAR), Singapore
| | - Duong Socheat
- The National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Paul N Newton
- Wellcome Trust-Mahosot Hospital-Oxford University Tropical Medicine Research Collaboration, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
| | - Nicholas PJ Day
- Mahidol-Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
| | - Nicholas J White
- Mahidol-Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
| | - Peter R Preiser
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - François Nosten
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
- Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Arjen M Dondorp
- Mahidol-Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore
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11
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Chinappi M, Via A, Marcatili P, Tramontano A. On the mechanism of chloroquine resistance in Plasmodium falciparum. PLoS One 2010; 5:e14064. [PMID: 21124966 PMCID: PMC2988812 DOI: 10.1371/journal.pone.0014064] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 10/28/2010] [Indexed: 11/18/2022] Open
Abstract
Resistance to chloroquine of malaria strains is known to be associated with a parasite protein named PfCRT, the mutated form of which is able to reduce chloroquine accumulation in the digestive vacuole of the pathogen. Whether the protein mediates extrusion of the drug acting as a channel or as a carrier and which is the protonation state of its chloroquine substrate is the subject of a scientific debate. We present here an analytical approach that explores which combination of hypotheses on the mechanism of transport and the protonation state of chloroquine are consistent with available equilibrium experimental data. We show that the available experimental data are not, by themselves, sufficient to conclude whether the protein acts as a channel or as a transporter, which explains the origin of their different interpretation by different authors. Interestingly, though, each of the two models is only consistent with a subset of hypotheses on the protonation state of the transported molecule. The combination of these results with a sequence and structure analysis of PfCRT, which strongly suggests that the molecule is a carrier, indicates that the transported species is either or both the mono and di-protonated forms of chloroquine. We believe that our results, besides shedding light on the mechanism of chloroquine resistance in P. falciparum, have implications for the development of novel therapies against resistant malaria strains and demonstrate the usefulness of an approach combining systems biology strategies with structural bioinformatics and experimental data.
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Affiliation(s)
- Mauro Chinappi
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
| | - Allegra Via
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
| | - Paolo Marcatili
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
| | - Anna Tramontano
- Department of Biochemical Sciences, Sapienza University, Rome, Italy
- Istituto Pasteur, Fondazione Cenci Bolognetti, Sapienza University, Rome, Italy
- * E-mail:
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12
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Patel JJ, Thacker D, Tan JC, Pleeter P, Checkley L, Gonzales JM, Deng B, Roepe PD, Cooper RA, Ferdig MT. Chloroquine susceptibility and reversibility in a Plasmodium falciparum genetic cross. Mol Microbiol 2010; 78:770-87. [PMID: 20807203 DOI: 10.1111/j.1365-2958.2010.07366.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mutations in the Plasmodium falciparum chloroquine (CQ) resistance transporter (PfCRT) are major determinants of verapamil (VP)-reversible CQ resistance (CQR). In the presence of mutant PfCRT, additional genes contribute to the wide range of CQ susceptibilities observed. It is not known if these genes influence mechanisms of chemosensitization by CQR reversal agents. Using quantitative trait locus (QTL) mapping of progeny clones from the HB3 × Dd2 cross, we show that the P. falciparum multidrug resistance gene 1 (pfmdr1) interacts with the South-East Asia-derived mutant pfcrt haplotype to modulate CQR levels. A novel chromosome 7 locus is predicted to contribute with the pfcrt and pfmdr1 loci to influence CQR levels. Chemoreversal via a wide range of chemical structures operates through a direct pfcrt-based mechanism. Direct inhibition of parasite growth by these reversal agents is influenced by pfcrt mutations and additional loci. Direct labelling of purified recombinant PfMDR1 protein with a highly specific photoaffinity CQ analogue, and lack of competition for photolabelling by VP, supports our QTL predictions. We find no evidence that pfmdr1 copy number affects CQ response in the progeny; however, inheritance patterns indicate that an allele-specific interaction between pfmdr1 and pfcrt is part of the complex genetic background of CQR.
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Affiliation(s)
- Jigar J Patel
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, 205 Galvin Life Sciences, Notre Dame, IN 46556, USA
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Hayton K, Su XZ. Drug resistance and genetic mapping in Plasmodium falciparum. Curr Genet 2008; 54:223-39. [PMID: 18802698 DOI: 10.1007/s00294-008-0214-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2008] [Revised: 08/27/2008] [Accepted: 08/28/2008] [Indexed: 11/30/2022]
Abstract
Drug resistance in malaria parasites is a serious public health burden, and resistance to most of the antimalarial drugs currently in use has been reported. A better understanding of the molecular mechanisms of drug resistance is urgently needed to slow or circumvent the spread of resistance, to allow local treatments to be deployed more effectively to prolong the life span of the current drugs, and to develop new drugs. Although mutations in genes determining resistance to drugs such as chloroquine and the antifolates have been identified, we still do not have a full understanding of the resistance mechanisms, and genes that contribute to resistance to many other drugs remain to be discovered. Genetic mapping is a powerful tool for the identification of mutations conferring drug resistance in malaria parasites because most drug-resistant phenotypes were selected within the past 60 years. High-throughput methods for genotyping large numbers of single nucleotide polymorphisms (SNPs) and microsatellites (MSs) are now available or are being developed, and genome-wide association studies for malaria traits will soon become a reality. Here we discuss strategies and issues related to mapping genes contributing to drug resistance in the human malaria parasite Plasmodium falciparum.
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Affiliation(s)
- Karen Hayton
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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14
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Schlitzer M. Antimalarial drugs - what is in use and what is in the pipeline. Arch Pharm (Weinheim) 2008; 341:149-63. [PMID: 18297679 DOI: 10.1002/ardp.200700184] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Malaria continues to be a potentially fatal threat to almost half of the world's population. In light of this threat, the armory to fight this disease is rather limited. Resistance against the most common and affordable antimalarials is widespread. Only few new drugs are in clinical development, most of them belong to long used classes of antimalarial drugs. This review will concisely cover the drugs which are currently in use, and describe the drug candidates which are in clinical evaluation.
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Affiliation(s)
- Martin Schlitzer
- Philipps-Universität, Institut für Pharmazeutische Chemie, Marburg, Germany.
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Francischetti IMB, Seydel KB, Monteiro RQ. Blood coagulation, inflammation, and malaria. Microcirculation 2008; 15:81-107. [PMID: 18260002 DOI: 10.1080/10739680701451516] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Malaria remains a highly prevalent disease in more than 90 countries and accounts for at least 1 million deaths every year. Plasmodium falciparum infection is often associated with a procoagulant tonus characterized by thrombocytopenia and activation of the coagulation cascade and fibrinolytic system; however, bleeding and hemorrhage are uncommon events, suggesting that a compensated state of blood coagulation activation occurs in malaria. This article (i) reviews the literature related to blood coagulation and malaria in a historic perspective, (ii) describes basic mechanisms of coagulation, anticoagulation, and fibrinolysis, (iii) explains the laboratory changes in acute and compensated disseminated intravascular coagulation (DIC), (iv) discusses the implications of tissue factor (TF) expression in the endothelium of P. falciparum infected patients, and (v) emphasizes the procoagulant role of parasitized red blood cells (RBCs) and activated platelets in the pathogenesis of malaria. This article also presents the Tissue Factor Model (TFM) for malaria pathogenesis, which places TF as the interface between sequestration, endothelial cell (EC) activation, blood coagulation disorder, and inflammation often associated with the disease. The relevance of the coagulation-inflammation cycle for the multiorgan dysfunction and coma is discussed in the context of malaria pathogenesis.
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Affiliation(s)
- Ivo M B Francischetti
- Vector Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA.
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Abstract
Widespread parasitic resistance has led to an urgent need for the development and implementation of new drugs for the treatment of Plasmodium falciparum malaria. Artemisinin and its derivatives are becoming increasingly important, used preferably in combination with a second antimalarial agent to increase the efficacy and slow the development of resistance. However, cost, production and pharmacological issues associated with artemisinin derivatives and potential partner drugs are hindering the implementation of combination therapies. This article reviews the molecular basis of the action of, and resistance to, different antimalarials and examines the prospects for the next generation of drugs to combat this potentially lethal human pathogen.
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Affiliation(s)
- Leann Tilley
- Department of Biochemistry, La Trobe University, Melbourne, Victoria, Australia.
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17
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Schlitzer M. Malaria Chemotherapeutics Part I: History of Antimalarial Drug Development, Currently Used Therapeutics, and Drugs in Clinical Development. ChemMedChem 2007; 2:944-86. [PMID: 17530725 DOI: 10.1002/cmdc.200600240] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Since ancient times, humankind has had to struggle against the persistent onslaught of pathogenic microorganisms. Nowadays, malaria is still the most important infectious disease worldwide. Considerable success in gaining control over malaria was achieved in the 1950s and 60s through landscaping measures, vector control with the insecticide DDT, and the widespread administration of chloroquine, the most important antimalarial agent ever. In the late 1960s, the final victory over malaria was believed to be within reach. However, the parasites could not be eradicated because they developed resistance against the most widely used and affordable drugs of that time. Today, cases of malaria infections are on the rise and have reached record numbers. This review gives a short description of the malaria disease, briefly addresses the history of antimalarial drug development, and focuses on drugs currently available for malaria therapy. The present knowledge regarding their mode of action and the mechanisms of resistance are explained, as are the attempts made by numerous research groups to overcome the resistance problem within classes of existing drugs and in some novel classes. Finally, this review covers all classes of antimalarials for which at least one drug candidate is in clinical development. Antimalarial agents that are solely in early development stages will be addressed in a separate review.
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Affiliation(s)
- Martin Schlitzer
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany.
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Keen J, Farcas GA, Zhong K, Yohanna S, Dunne MW, Kain KC. Real-time PCR assay for rapid detection and analysis of PfCRT haplotypes of chloroquine-resistant Plasmodium falciparum isolates from India. J Clin Microbiol 2007; 45:2889-93. [PMID: 17609321 PMCID: PMC2045286 DOI: 10.1128/jcm.02291-06] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chloroquine-resistant Plasmodium falciparum (CRPF) malaria isolates in Southeast Asia and sub-Saharan Africa share the same Plasmodium falciparum chloroquine resistance transporter (PfCRT) haplotype (CVIET; amino acids 72 to 76). It is believed that CRPF malaria emerged in Southeast Asia and spread to sub-Saharan Africa via the Indian subcontinent. Based on this assumption, we hypothesized that CRPF isolates in India should possess the same drug resistance haplotype (PfCRT haplotype CVIET) as P. falciparum isolates in Southeast Asia and Africa and that the prevalence of CRPF may be higher and more widespread in India than appreciated. To test this postulate, we utilized a standardized real-time PCR assay to assess the prevalence and distribution of PfCRT haplotypes in P. falciparum isolates (n = 406) collected from Western, Central, and Eastern states in India and compared them to isolates from South America and Africa. Based on the proportion of isolates possessing the molecular marker K76T, the prevalence of chloroquine resistance was high in all five regions of India studied (91%), as well as in Uganda (98%) and Suriname (100%). All isolates from Suriname contained the chloroquine-resistant SVMNT haplotype typical of South American isolates, and 98% of isolates from Uganda possessed the chloroquine-resistant CVIET haplotype characteristic of Southeast Asian/African strains. However, of 246 P. falciparum isolates from across India that contained the molecular marker for chloroquine resistance, 81% contained the SVMNT haplotype. In conclusion, the prevalence of CRPF malaria was high in geographically dispersed regions of India, and the primary haplotype observed, SVMNT, did not support a presumed geographic spread from contiguous Southeast Asia.
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Affiliation(s)
- Jessica Keen
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada
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Noranate N, Durand R, Tall A, Marrama L, Spiegel A, Sokhna C, Pradines B, Cojean S, Guillotte M, Bischoff E, Ekala MT, Bouchier C, Fandeur T, Ariey F, Patarapotikul J, Bras JL, Trape JF, Rogier C, Mercereau-Puijalon O. Rapid dissemination of Plasmodium falciparum drug resistance despite strictly controlled antimalarial use. PLoS One 2007; 2:e139. [PMID: 17206274 PMCID: PMC1764034 DOI: 10.1371/journal.pone.0000139] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Accepted: 12/06/2006] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Inadequate treatment practices with antimalarials are considered major contributors to Plasmodium falciparum resistance to chloroquine, pyrimethamine and sulfadoxine. The longitudinal survey conducted in Dielmo, a rural Senegalese community, offers a unique frame to explore the impact of strictly controlled and quantified antimalarial use for diagnosed malaria on drug resistance. METHODOLOGY/PRINCIPAL FINDINGS We conducted on a yearly basis a retrospective survey over a ten-year period that included two successive treatment policies, namely quinine during 1990-1994, and chloroquine (CQ) and sulfadoxine/pyrimethamine (SP) as first and second line treatments, respectively, during 1995-1999. Molecular beacon-based genotyping, gene sequencing and microsatellite analysis showed a low prevalence of Pfcrt and Pfdhfr-ts resistance alleles of Southeast Asian origin by the end of 1994 and their effective dissemination within one year of CQ and SP implementation. The Pfcrt resistant allele rose from 9% to 46% prevalence during the first year of CQ reintroduction, i.e., after a mean of 1.66 CQ treatment courses/person/year. The Pfdhfr-ts triple mutant rose from 0% to 20% by end 1996, after a mean of 0.35 SP treatment courses/person in a 16-month period. Both resistance alleles were observed at a younger age than all other alleles. Their spreading was associated with enhanced in vitro resistance and rapidly translated in an increased incidence of clinical malaria episodes during the early post-treatment period. CONCLUSION/SIGNIFICANCE In such a highly endemic setting, selection of drug-resistant parasites took a single year after drug implementation, resulting in a rapid progression of the incidence of clinical malaria during the early post-treatment period. Controlled antimalarial use at the community level did not prevent dissemination of resistance haplotypes. This data pleads against reintroduction of CQ in places where resistant allele frequency has dropped to a very low level after CQ use has been discontinued, unless drastic measures are put in place to prevent selection and spreading of mutants during the post-treatment period.
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Affiliation(s)
- Nitchakarn Noranate
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rémy Durand
- Hôpital Avicenne, Assistance Publique-Hôpitaux de Paris, Bobigny, France
| | - Adama Tall
- Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal
| | - Laurence Marrama
- Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal
| | - André Spiegel
- Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal
| | - Cheikh Sokhna
- Laboratoire de Paludologie/Zoologie Médicale, IRD, Dakar, Senegal
| | - Bruno Pradines
- Institut de Médecine Tropicale du Service de Santé des Armées, Marseille, France
| | - Sandrine Cojean
- Transports Membranaires et Chimiorésistance du Paludisme, Université R. Descartes and Hôpital Bichat Claude Bernard, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Micheline Guillotte
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
| | - Emmanuel Bischoff
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
| | - Marie-Thérèse Ekala
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
| | - Christiane Bouchier
- Pasteur Génopole-Ile de France, Plateforme Genomique, Institut Pasteur, Paris, France
| | | | | | | | - Jacques Le Bras
- Transports Membranaires et Chimiorésistance du Paludisme, Université R. Descartes and Hôpital Bichat Claude Bernard, Assistance Publique-Hôpitaux de Paris, Paris, France
| | | | - Christophe Rogier
- Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal
- Institut de Médecine Tropicale du Service de Santé des Armées, Marseille, France
| | - Odile Mercereau-Puijalon
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
- * To whom correspondence should be addressed. E-mail:
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Anquetin G, Greiner J, Mahmoudi N, Santillana-Hayat M, Gozalbes R, Farhati K, Derouin F, Aubry A, Cambau E, Vierling P. Design, synthesis and activity against Toxoplasma gondii, Plasmodium spp., and Mycobacterium tuberculosis of new 6-fluoroquinolones. Eur J Med Chem 2006; 41:1478-93. [PMID: 17000032 DOI: 10.1016/j.ejmech.2006.07.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 06/28/2006] [Accepted: 07/03/2006] [Indexed: 11/20/2022]
Abstract
This paper reports on the rational design of a series of new 6-fluoroquinolones by QSAR analysis against Toxoplasma (T.) gondii, their synthesis, their biological evaluation against T. gondii and Plasmodium (P.) spp., and their effect on Mycobacterium (M.) tuberculosis DNA gyrase and growth inhibition. Of the 12 computer-designed 8-ethyl(or methoxy)- and 5-ethyl-8-methoxy-6-fluoroquinolones predicted to be active against T. gondii, we succeeded in the synthesis of four 6-fluoro-8-methoxy-quinolones. The four 6-fluoro-8-methoxy-quinolones are active on T. gondii but only one is as active as predicted. One of these four compounds appears to be an antiparasitical drug of great potential with inhibitory activities comparable to or higher than that of trovafloxacin, gatifloxacin, and moxifloxacin. They also inhibit DNA supercoiling by M. tuberculosis gyrase with an efficiency comparable to that of the most active quinolones but are poor inhibitors of M. tuberculosis growth.
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Affiliation(s)
- Guillaume Anquetin
- Laboratoire de Chimie Bioorganique UMR-CNRS 6001, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2, France
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Madrid PB, Liou AP, DeRisi JL, Guy RK. Incorporation of an intramolecular hydrogen-bonding motif in the side chain of 4-aminoquinolines enhances activity against drug-resistant P. falciparum. J Med Chem 2006; 49:4535-43. [PMID: 16854059 PMCID: PMC1524878 DOI: 10.1021/jm0600951] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous data showing that several chloroquine analogues containing an intramolecular hydrogen-bonding motif were potent against multidrug-resistant P. falciparum led to the exploration of the importance of this motif. A series of 116 compounds containing four different alkyl linkers and various aromatic substitutions with hydrogen bond accepting capability was synthesized. The series showed broad potency against the drug-resistant W2 strain of P. falciparum. In particular, a novel series containing variations of the alpha-aminocresol motif gave eight compounds with IC50 values more potent than 5 nM against the W2 strain. Such simple modifications, significantly altering the pKa and sterics of the basic side chain in chloroquine analogues, may prove to be part of a strategy for overcoming the problem of worldwide resistance to affordable antimalarial drugs.
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Affiliation(s)
- Peter B Madrid
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143-2280, USA
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Farcas GA, Soeller R, Zhong K, Zahirieh A, Kain KC. Real-Time Polymerase Chain Reaction Assay for the Rapid Detection and Characterization of Chloroquine-Resistant Plasmodium falciparum Malaria in Returned Travelers. Clin Infect Dis 2006; 42:622-7. [PMID: 16447106 DOI: 10.1086/500134] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2005] [Accepted: 10/16/2005] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Imported drug-resistant malaria is a growing problem in industrialized countries. Rapid and accurate diagnosis is essential to prevent malaria-associated mortality in returned travelers. However, outside of a limited number of specialized centers, the microscopic diagnosis of malaria is slow, unreliable, and provides little information about drug resistance. Molecular diagnostics have the potential to overcome these limitations. OBJECTIVE We developed and evaluated a rapid, real-time polymerase chain reaction (PCR) assay to detect Plasmodium falciparum malaria and chloroquine (CQ)-resistance determinants in returned travelers who are febrile. METHODS A real-time PCR assay based on detection of the K76T mutation in PfCRT (K76T) of P. falciparum was developed on a LightCycler platform (Roche). The performance characteristics of the real-time assay were compared with those of the nested PCR-restriction fragment-length polymorphism (RFLP) and the sequence analyses of samples obtained from 200 febrile returned travelers, who included 125 infected with P. falciparum (48 of whom were infected CQ-susceptible [K76] and 77 of whom were CQ-resistant [T76] P. falciparum), 22 infected with Plasmodium vivax, 10 infected with Plasmodium ovale, 3 infected with Plasmodium malariae malaria, and 40 infected with other febrile syndromes. All patient samples were coded, and all analyses were performed blindly. RESULTS The real-time PCR assay detected multiple pfcrt haplotypes associated with CQ resistance in geographically diverse malaria isolates acquired by travelers. Compared with nested-PCR RFLP (the reference standard), the real-time assay was 100% sensitive and 96.2% specific for detection of the P. falciparum K76T mutation. CONCLUSION This assay is rapid, sensitive, and specific for the detection and characterization of CQ-resistant P. falciparum malaria in returned travelers. This assay is automated, standardized, and suitable for routine use in clinical diagnostic laboratories.
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Affiliation(s)
- Gabriella A Farcas
- Tropical Disease Unit, University Health Network-Toronto General Hospital, Toronto, Ontario, Canada
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Labie D. Résistance du Plasmodiumà la chloroquine : vers un ciblage de l’attaque ? Med Sci (Paris) 2005; 21:463-5. [PMID: 15885191 DOI: 10.1051/medsci/2005215463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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