FOSMIDOMYCIN RESISTANCE IN PLASMODIUM FALCIPARUM

恶性疟原虫对磷米霉素的耐药性

• 批准号: 8420970
• 负责人: Audrey Ragan Odom John
• 金额: $ 31.56万
• 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/8420970
• 关键词: Anabolism; Antimalarials; Antiparasitic Agents; Artemisinins; Biochemical; Biochemical Genetics; Biochemical Pathway; Biological; Biological Markers; Biology; Cessation of life; Chemicals; Chloroquine resistance; Clinical Trials; Collection; Combined Modality Therapy; Data; Development; Diagnostic; 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; Signs and Symptoms; Validation; antimicrobial drug; artemisinine; base; drug development; fosmidomycin; gene replacement; genetic analysis; genome sequencing; improved; inhibitor/antagonist; innovation; isoprenoid; killings; meetings; mutant; next generation; next generation sequencing; novel; pathogen; positional cloning; prenylation; protein metabolism; public health relevance; resistance mutation; resistant strain; small molecule

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（由申请人提供）：恶性疟原虫是一种原生动物病原体，导致最致命的疟疾形式。疟疾对全世界的人类健康产生了巨大影响，每年造成近100万人死亡。由于广泛的氯喹耐药性和对青蒿素的耐药性，因此迫切需要新的疗法来治疗这种疾病。恶性疟原虫具有必不可少的代谢途径，非甲酸异丙甲酸酯类生物合成（MEP途径），该途径在人类中不存在。该途径是一种特别诱人的抗疟药，因为它由其他重要的人类病原体（包括革兰氏阴性菌和结核分枝杆菌）共享。长期的目标是了解为什么类异型在疟疾寄生虫中至关重要。 Fosmidomycin是MEP途径的验证抑制剂，目前正在联合治疗疟疾的II期临床试验中。在初步研究中，已经开发出了抗霉素抗性疟疾的寄生虫的集合，该寄生虫不仅缺乏该药物的已知靶标的突变，而且即使在抑制了类吸收性生物合成的情况下，也会继续增长。这些抗霉素抗性菌株大概是通过“救援途径”中的遗传变化而生存的。该建议的目的是确定这些寄生虫具有抗性的生化和遗传机制。这些研究的基本原理是，鉴定了与fosmidymycin遗传相互作用的基因和途径，将为恶性疟原虫中异普尼生物合成的调节和下游生物学提供信息。了解fosmidomycin抗性疟疾菌株尽管抑制了类异戊二烯生物合成，但如何生存 阐明为什么类异丙基通常是必不可少的。这种方法利用了病原体特异性的生化途径和一种在临床试验中的类异急动物生物合成的有效化学抑制剂。在强大的初步数据的支持下，表明该策略取得成功，将通过三个特定目的实现目标：1）对fosmidonycin-耐药的马拉里亚寄生虫的MEP代谢和蛋白质原化的代谢分析； 2）通过下一代测序策略对fosmidomycin抗性疟疾的遗传分析； 3）通过概括敏感的野生型寄生虫线中的候选耐药性突变来鉴定赋予fosmidomycin抗性的遗传变化。这种方法具有创新性，因为它使用抗药性疟疾寄生虫的遗传表征不仅用于药物靶标验证，而且还可以扩大对必需代谢途径的基本生物学理解。拟议的研究很重要，因为它将鉴定fosmidomycin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发展的新靶标。