FOSMIDOMYCIN RESISTANCE IN PLASMODIUM FALCIPARUM

恶性疟原虫对磷米霉素的耐药性

• 批准号: 8770021
• 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 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8770021
• 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; forward genetics; fosmidomycin; gene replacement; genetic analysis; genome sequencing; improved; inhibitor/antagonist; innovation; isoprenoid; killings; meetings; mutant; next generation; next generation sequencing; novel; pathogen; prenylation; protein metabolism; resistance mutation; resistant strain; reverse genetics; 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）：恶性疟原虫是一种引起最致命形式疟疾的原生动物病原体。疟疾对全世界人类健康产生巨大影响，每年造成近100万人死亡。由于普遍存在氯喹耐药性和对青蒿素的耐药性，迫切需要新的疗法来治疗这种疾病。恶性疟原虫具有一个必要的代谢途径，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。这一途径是一个特别诱人的抗疟药物靶点，因为它与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。长期目标是了解为什么类异戊二烯对疟疾寄生虫至关重要。Fosmidomycin是一种经过验证的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，已经培育出一批对fosmidomycin耐药的疟疾寄生虫，它们不仅在这种药物的已知靶点上缺乏突变，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。这些耐fosmidomycin的菌株可能通过“拯救途径”中的遗传变化存活下来。这项建议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，鉴定与fosmidomycin遗传相互作用的基因和途径将为恶性疟原虫类异戊二烯生物合成的调控和下游生物学提供信息。了解耐fosmidomy霉素的疟疾菌株是如何在类异戊二烯生物合成受到抑制的情况下存活下来的，将有助于我们的研究