Targeting the Mitochondrion of P. falciparum

靶向恶性疟原虫的线粒体

• 批准号: 9263872
• 负责人: Dyann F Wirth
• 金额: $ 58.69万
• 依托单位: HARVARD SCHOOL OF PUBLIC HEALTH
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-06 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9263872
• 关键词: Anabolism; Anti-malarial drug resistance; Antimalarials; Artemisinins; Award; Biochemical; Biological; Biological Assay; Biological Models; Biology; Chemicals; Chloroquine; Combined Modality Therapy; Consumption; Crystallography; Cultured Cells; DHODH gene; Data; Development; Dihydroorotate Dehydrogenase Inhibitor; Dihydroorotate dehydrogenase; Drug resistance; Drug resistance pathway; Drug-sensitive; Environment; Enzyme Kinetics; Enzymes; Fansidar; Growth; Human; In Vitro; Infection; Investigation; Kinetics; Knowledge; Malaria; Measures; Mefloquine; Methodology; Methods; Mitochondria; Monitor; Mutation; Organism; Parasites; Pathway interactions; Pharmaceutical Chemistry; Pharmaceutical Preparations; Pharmacologic Substance; Plasmodium falciparum; Population; Process; Protocols documentation; Publications; Pyrimidine; Reagent; Resistance; Resistance development; Structure; Testing; Whole Organism; Work; base; chemotherapy; clinically relevant; comparative; cost; design; drug candidate; enzyme activity; experimental study; fitness; high throughput screening; humanized mouse; in vivo; in vivo Model; inhibitor/antagonist; innovation; killings; mouse model; mutant; novel therapeutics; pressure; prevent; programs; public health relevance; resistance mutation; screening; single molecule; tool; vector control

 DESCRIPTION (provided by applicant): Drug resistance remains a pressing concern for antimalarial chemotherapies. Management of resistance has largely been a reactive process, but here we propose a proactive approach that exploits predicted evolutionary trajectories to maintain a drug-sensitive parasite population. Our strategy is to design new drugs such that the fitness cost of resistance restricts the ability of mutant parasites to survive combination therapy or to persist in the absence of selection. Through whole organism high-throughput screening we have discovered many new chemotypes that act on mitochondrial targets and either in combination or in a single molecule target both wild-type and mutant parasites and suppress the emergence of resistance in vitro. Here we focus on the Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) target and fully explore the structural, functional, and fitness consequences of drug resistance pathways. We extend the findings from our current award to fully explore mutually incompatible resistance, establishing an in vivo model system to understand the impact of the host environment on the parasite's ability to escape drug pressure. PfDHODH is clinically relevant and has multiple structural classes of inhibitors providing a substantial toolset with which to study our combination strategy in depth. We will identify chemical inhibitors that target wild-type and mutant forms of DHODH and optimize efficacy for in vivo studies. Using an approach that has proven highly productive, we will prioritize the molecules based on cross-resistance screening against a panel of resistant mutants and focus on compounds demonstrating validated potency against both the wild-type and mutants. We will validate the resistance mutations and assess the structural and biological consequences of these mutations by determining the structures of the most prevalent mutant forms, measuring the effects of the mutations on the enzyme, on mitochondrial function, and on the growth of the organism. We will develop a protocol for using a humanized mouse model of P. falciparum infection to measure the most relevant in vivo resistance pathways and test the suppression of drug resistance. This has implications not just for this work, but also for others in the field who are developing methods to prevent the emergence of drug resistance.

 描述（由申请人提供）：耐药性仍然是抗疟化疗的一个紧迫问题。耐药性管理在很大程度上是一个反应过程，但在这里我们提出了一种主动方法，利用预测的进化轨迹来维持对药物敏感的寄生虫种群。我们的策略是设计新药，使耐药性的适应成本限制突变寄生虫在联合治疗中生存的能力 或者在没有选择的情况下坚持下去。通过整个生物体的高通量筛选，我们发现了许多作用于线粒体靶标的新化学型，并且以组合或单个分子的形式同时靶向野生型和突变型寄生虫并抑制体外耐药性的出现。在这里，我们重点关注恶性疟原虫二氢乳清酸脱氢酶（PfDHODH）靶标，并充分探讨耐药途径的结构、功能和适应性后果。我们扩展了当前奖项的研究结果，以充分探索相互不相容的耐药性，建立体内模型系统以了解宿主环境对寄生虫逃避药物压力的能力的影响。 PfDHODH 具有临床相关性，并具有多种结构类别的抑制剂，为深入研究我们的组合策略提供了丰富的工具集。我们将鉴定针对 DHODH 野生型和突变型的化学抑制剂，并优化体内研究的功效。使用一种已被证明高效的方法，我们将根据针对一组耐药突变体的交叉耐药性筛选来优先考虑分子，并重点关注对野生型和突变体均具有验证效力的化合物。我们将通过确定最常见突变形式的结构、测量突变对酶、线粒体功能和生物体生长的影响来验证抗性突变并评估这些突变的结构和生物学后果。我们将开发一种方案，使用恶性疟原虫感染的人源化小鼠模型来测量最相关的体内耐药途径并测试耐药性的抑制。这不仅对这项工作有影响，而且对该领域的其他人也有影响 正在开发防止耐药性出现的方法。