Dissecting Chloroquine Resistance in the Plasmodium vivax Cross

剖析间日疟原虫交叉中的氯喹耐药性

• 批准号: 8682061
• 负责人: Jonathan J Juliano
• 金额: $ 24.7万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-11 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8682061
• 关键词: 6H,8H-3,4-dihydropyrimido(4,5-c)(1,2)oxazin-7-one; Africa; Aftercare; Alleles; Amino Acid Substitution; Antimalarials; Artemisinins; Biology; Blood; Cambodia; Chloroquine; Chloroquine resistance; Chromosome Mapping; Clinical; Cloning; Codon Nucleotides; Collaborations; Combined Modality Therapy; Country; Cross Infection; DNA; Development; Drug resistance; Event; Falciparum Malaria; Genetic; Genetic Crosses; Genomics; Goals; Growth; Hybrids; In Vitro; Indonesia; Infection; Laboratories; Life Cycle Stages; Malaria; Measurement; Methods; Modeling; Molecular; Monkeys; Morbidity - disease rate; Mutation; Orthologous Gene; Pan Genus; Parasite resistance; Parasitemia; Parasites; Parents; Persons; Pharmaceutical Preparations; Plasmodium falciparum; Plasmodium vivax; Public Health; Recombinants; Recrudescences; Research; Resistance; Resources; Risk; Rodent Model; Sampling; Southeastern Asia; Staging; Time; Transfection; United States National Institutes of Health; Variant; Vivax Malaria; artemisinine; base; comparative; genome sequencing; genome-wide; in vivo; indexing; innovation; interest; molecular marker; mortality; neglect; nonhuman primate; pressure; public health relevance; research study; resistance allele; resistance mechanism; resistant strain; response; tool

DESCRIPTION (provided by applicant): Despite the recent surge of interest in malaria, Plasmodium vivax has remained relatively neglected compared to falciparum malaria. Over 2.5 billion persons are at risk of vivax infection, which causes between 80 and 300 million cases per year. The principal drug in use today for vivax malaria is chloroquine (CQ) but its efficacy in now threatened by evolving resistance. Over the past 20 years, CQ resistance emerged in Western Pacifica and Southeast (SE) Asia and is now spreading worldwide. In some countries, such as Cambodia and Indonesia, the diminished efficacy of CQ therapy has prompted a change to artemisinin combination therapies (ACTs), which are significantly more costly, as first-line therapy for vivax malaria. The molecular basis of P. vivax CQ resistance remains unknown. Evidence indicates that the genetic events underlying P. vivax CQ resistance differs from P. falciparum as no association was found between in vivo drug responses and codon changes in Plasmodium vivax chloroquine resistance transporter (pvcrt), the P. vivax ortholog of Plasmodium falciparum chloroquine resistance transporter (pfcrt). Further research on CQ-resistant P. vivax has been severely hampered by the lack of critical tools to study the parasites including in vitro culture, DNA transfection and cloning methods. Therefore research on P. vivax CQ resistance depends on non-human primate models. Recently, the National Institutes of Health (NIH) invested significant resources to generate the first P. vivax genetic cross between a CQ sensitive strain and a CQ resistant strain in a chimpanzee. Using this cross, our proposal is aimed at determining the genetic loci underlying CQ resistance in P. vivax by conducting a linkage group selection (LGS) analysis leveraging whole genome sequencing of parental strains and in vivo mixed progeny infections before and after drug pressure. Without the need for traditional clonal analysis and defined IC50s, LGS identifies shifts toward resistant parental alleles after selection with CQ indicative of genetic loci associated with CQ resistance and has been used to successfully identify resistance alleles/mutations multiple times in malaria rodent models. This proposal is clearly significant for multiple reasons: 1) CQ resistant vivax is a major global public health problem causing significant morbidity and mortality with significant financial implications, 2) this will be the first genome-wide assessment for genetic loci of CQ resistance in vivax malaria using a defined genetic cross, 3) it leverages a set of samples from a unique and irreplaceable genetic cross generated in a chimpanzee, the approach which identified the key P. falciparum mutations for resistance to CQ and other antimalarials, 4) identification of CQ resistance mechanisms will aid in the development of additional antimalarials, and 5) identification of loci associated with CQ resistance will provide molecular markers of resistance, an important public health tool for studying the spread of resistance. The proposal is also innovative as it leverages new tools for conducting whole genome sequencing using hybrid capture to enrich parasite DNA and remove contaminating host DNA. Understanding the molecular basis for CQ resistance in P. vivax would be a major advance in understanding of vivax biology and has the potential to have profound impacts on global public health.

描述（由申请人提供）：尽管最近对疟疾的兴趣激增，但与恶性疟疾相比，Vivax仍然相对忽视。超过25亿人有体内感染的风险，每年导致80至3亿例病例。今天使用的主要药物是氯喹（CQ），但现在的功效 受到不断发展的抵抗的威胁。在过去的20年中，CQ抵抗在西太平洋和东南亚（SE）亚洲出现，现在正在全球范围内传播。在某些国家，例如柬埔寨和印度尼西亚，CQ疗法的疗效降低导致对小抵抗素组合疗法（ACT）的变化，这是对Vivax疟疾的一线疗法的变化。维瓦克斯CQ抗性的分子基础仍然未知。证据表明，维瓦克斯·CQ（Vivax CQ）的遗传事件与恶性疟原虫的抗性不同，因为在体内药物反应与疟原虫氯喹抗性转运蛋白（PVCRT）的密码子之间未发现任何关联，疟原虫疟原虫的疟原虫氯菌氯喹啉抗氯酸疟原虫的抗性疟原虫抗性抗体抗性抗体抗性（PFCRTCRTCRTCRTCRTCRTCRT）缺乏研究寄生虫（包括体外培养，DNA转染和克隆方法）的关键工具，对耐CQ抗性疟原虫的进一步研究受到了严重的阻碍。因此，对维瓦克斯CQ抗性的研究取决于非人类灵长类动物模型。最近，美国国立卫生研究院（NIH）投入了大量资源，以在黑猩猩的CQ敏感性和CQ抗性菌株之间产生第一个Vivax遗传交叉。使用这个十字架，我们的建议旨在通过进行链接组选择（LGS）分析来确定遗传基因座的遗传基因座的遗传基因座，从而利用了父母菌株和体内混合后代感染的整个基因组测序。不需要传统的克隆分析和定义的IC50，LGS在选择CQ之后鉴定出向抗性父母等位基因的转变，指示与CQ耐药性相关的遗传基因座，并已用于在疟疾啮齿动物模型中多次成功识别抗性等位基因/突变。由于多种原因，该提案显然很重要：1）CQ抗性Vivax是主要的 全球公共卫生问题，导致大量发病率和死亡率，并具有巨大的财务状况 含义，2）这将是CQ耐药性遗传遗传基因座的第一个全基因组评估 使用定义的遗传杂交，3）它利用黑猩猩在黑猩猩中产生的独特且不可替代的遗传杂交中的一组样品，这种方法确定了鉴定出对CQ和其他抗磁性机制的抗CQ和其他抗抗性机制的关键恶性假单胞菌突变的关键抗药性和其他抗抗性机制的识别，并将其与CQ电阻识别相关，并有助于识别CQ的发展，并在CQ的电阻中识别出CQ的发展，并且CQ电阻的识别是CQ的发展。提供抗性的分子标记，这是研究阻力传播的重要公共卫生工具。该提案也是创新的，因为它利用新工具使用混合捕获来富集寄生虫DNA并去除污染的宿主DNA进行整个基因组测序。理解在维瓦克斯疟原虫中CQ抗性的分子基础将是理解Vivax生物学的重大进步，并有可能对全球公共卫生产生深远的影响。