FOSMIDOMYCIN RESISTANCE IN PLASMODIUM FALCIPARUM

恶性疟原虫对磷米霉素的耐药性

• 批准号: 8968811
• 负责人: Audrey Ragan Odom John
• 金额: $ 34.2万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-01 至 2017-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8968811
• 关键词: Anabolism; Antimalarials; Antiparasitic Agents; Artemisinins; Biochemical; Biochemical Genetics; Biochemical Pathway; Biological; Biology; Cessation of life; Chemicals; Chloroquine resistance; Clinical Trials; Collection; Combined Modality Therapy; Data; Development; Disease; Drug Targeting; Drug resistance; Electron Transport; Enzymes; Future; Genes; Genetic; Genetic Engineering; Genome; Goals; Gram-Negative Bacteria; Health; Human; Knowledge; Lead; Malaria; Metabolic; Metabolic Pathway; Metabolism; Molecular; Mutation; Mycobacterium tuberculosis; Parasites; Pathway interactions; Pharmaceutical Preparations; Phase; Phase II Clinical Trials; Plasmodium falciparum; Process; Protein Isoprenylation; Public Health; Regulation; Research; Resistance; Signal Transduction; Validation; antimicrobial drug; artemisinine; base; diagnostic biomarker; drug development; forward genetics; fosmidomycin; gene replacement; genetic analysis; genome sequencing; improved; inhibitor/antagonist; innovation; isoprenoid; killings; meetings; mutant; new therapeutic target; next generation; next generation sequencing; novel; novel therapeutics; pathogen; prenylation; protein metabolism; resistance mutation; resistant strain; reverse genetics; small molecule; whole genome

DESCRIPTION (provided by applicant): Plasmodium falciparum is a protozoan pathogen that causes the deadliest form of malaria. Malaria has a tremendous impact on human health worldwide, causing nearly one million deaths per year. New therapies are urgently needed to treat this disease, due to widespread chloroquine resistance and emerging resistance to artemisinins. P. falciparum possesses an essential metabolic pathway, non-mevalonate isoprenoid biosynthesis (the MEP pathway), which is not present in humans. This pathway is a particularly enticing antimalarial drug target because it is shared by other important human pathogens, including Gram-negative bacteria and Mycobacterium tuberculosis. The long-term goal is to understand why isoprenoids are essential in malaria parasites. Fosmidomycin is a validated inhibitor of the MEP pathway and is currently in Phase II clinical trials of combination therapy to treat malaria. In preliminary studies, a collection of fosmidomycin-resistant malaria parasites have been developed that not only lack mutations in the known targets of this drug but also continue to grow even when isoprenoid biosynthesis is inhibited. These fosmidomycin-resistant strains presumably survive through genetic changes in a "rescue pathway." The objective of this proposal is to determine the biochemical and genetic mechanisms by which these parasites have become resistant. The rationale for these studies is that identification of the genes and pathways that genetically interact with fosmidomycin will inform the regulation and downstream biology of isoprenoid biosynthesis in P. falciparum. Understanding how fosmidomycin-resistant malaria strains survive, despite inhibition of isoprenoid biosynthesis, will elucidate why isoprenoids are typically essential. This approach takes advantage of a pathogen-specific biochemical pathway and a potent chemical inhibitor of isoprenoid biosynthesis that is already in clinical trials. Supported by strong preliminary data that indicate that this strategy wll be successful, the objectives will be met through three specific aims: 1) metabolic analysis of MEP metabolism and protein prenylation (an important function of isoprenoid biosynthesis) in fosmidomycin-resistant malaria parasites; 2) genetic analysis of fosmidomycin-resistant malaria parasites through next-generation sequencing strategies; and 3) identification of the genetic changes that confer fosmidomycin resistance, by recapitulating candidate resistance mutations in sensitive wild-type parasite lines. This approach is innovative, since it uses genetic characterization of drug-resistant malaria parasites not only for drug target validation, but also o expand the fundamental biological understanding of an essential metabolic pathway. The proposed research is significant, because it will identify diagnostic biomarkers of fosmidomycin resistance, improve functional annotation of "hypothetical" genes in the P. falciparum genome, and identify new targets for much-needed antimalarial drug development.

描述（申请人提供）：恶性疟原虫是一种原生动物病原体，可导致最致命的疟疾。疟疾对全世界的人类健康产生巨大影响，每年造成近100万人死亡。由于广泛存在的氯喹耐药性和新出现的青蒿素耐药性，迫切需要新的疗法来治疗这种疾病。恶性疟原虫具有一种必需的代谢途径，即非甲羟戊酸类异戊二烯生物合成（MEP途径），这在人类中不存在。该途径是一个特别诱人的抗疟疾药物靶点，因为它被其他重要的人类病原体所共享，包括革兰氏阴性菌和结核分枝杆菌。长期目标是了解为什么类异戊二烯在疟疾寄生虫中至关重要。磷霉素是一种有效的MEP途径抑制剂，目前正在进行联合治疗疟疾的II期临床试验。在初步研究中，已经开发出一系列对膦咪霉素具有耐药性的疟疾寄生虫，这些寄生虫不仅在这种药物的已知靶标中缺乏突变，而且即使在类异戊二烯生物合成受到抑制时也能继续生长。这些磷霉素耐药菌株可能通过“拯救途径”中的遗传变化而存活。“这项提案的目的是确定这些寄生虫产生抗药性的生化和遗传机制。这些研究的基本原理是，识别与磷霉素发生遗传相互作用的基因和途径将为恶性疟原虫中类异戊二烯生物合成的调控和下游生物学提供信息。了解尽管类异戊二烯生物合成受到抑制，但抗磷霉素疟疾菌株如何存活，将 解释为什么类异戊二烯是典型的必需品。这种方法利用了病原体特异性生化途径和已经在临床试验中的类异戊二烯生物合成的有效化学抑制剂。在强有力的初步数据的支持下，表明这种策略将是成功的，目标将通过三个具体目标来实现：1）MEP代谢和蛋白质异戊二烯化的代谢分析（类异戊二烯生物合成的一个重要功能）; 2）通过下一代测序策略对磷霉素抗性疟原虫进行遗传分析;和3）通过重现敏感野生型寄生虫系中的候选抗性突变，鉴定赋予磷咪霉素抗性的遗传变化。这种方法是创新的，因为它使用耐药疟疾寄生虫的遗传表征不仅用于药物靶标验证，而且还扩展了对基本代谢途径的基本生物学理解。这项拟议中的研究意义重大，因为它将确定磷霉素耐药性的诊断生物标志物，改善恶性疟原虫基因组中“假设”基因的功能注释，并确定急需的抗疟药物开发的新靶点。