Defining P. falciparum resistance to artemisinin-based combination therapies

恶性疟原虫对青蒿素联合疗法的耐药性的定义

• 批准号: 10372215
• 负责人: David A Fidock
• 金额: $ 45.25万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10372215
• 关键词: Address; Adoption; Africa; African; Alleles; Amodiaquine; Antimalarials; Artemisinins; Asian; Automobile Driving; Bar Codes; Biological; Biological Assay; Biomass; Blood; CRISPR/Cas technology; Cambodia; Cambodian; Candidate Disease Gene; Cessation of life; Chromosome 12; Combined Modality Therapy; Containment; Country; Data; Development; Drug resistance; Drug usage; Effectiveness; Endocytosis; Eritrea; Face; Failure; Falciparum Malaria; Genes; Genetic; Genetic Crosses; Genomics; Geography; Growth; Haplotypes; Heme; Hemoglobin; Immunity; In Vitro; Lead; Malaria; Maps; Mediating; Microbial Drug Resistance; Morbidity - disease rate; Multi-Drug Resistance; Mutation; National Institute of Allergy and Infectious Disease; Parasite resistance; Parasites; Pharmaceutical Preparations; Plasmodium falciparum; Point Mutation; Population; Prevalence; Proteins; Quantitative Trait Loci; Research Support; Resistance; Risk; Rwanda; Southeastern Asia; Structure; Testing; Time; Treatment Failure; Uganda; asexual; base; benflumetol; biomarker identification; cost; deep sequencing; design; drug-sensitive; fitness; genome sequencing; humanized mouse; improved; innovation; insight; loss of function mutation; molecular marker; mortality; mutant; novel; pressure; programs; pyronaridine; resistance mutation; resistant Plasmodium falciparum; resistant strain; tool; transmission process; treatment strategy; whole genome

PROJECT SUMMARY The worldwide adoption of artemisinin (ART)-based combination therapies (ACTs) has been instrumental in halving the global burden of Plasmodium falciparum (Pf) malaria since the early 2000s; however, progress has stalled since 2015. Malaria’s impact remains vast, with an estimated 405,000 deaths in 2018. Now, Pf resistance to ART derivatives and their ACT partner drugs threatens to overwhelm control efforts. Parasites resistant to ART and piperaquine (PPQ), mediated primarily by mutations in the genes k13 and pfcrt respectively, have swept through the low-transmission setting of Southeast Asia. The development of ACT resistance in Africa, with 94% of the global malaria burden, would be calamitous. A major warning sign is the increasing prevalence of an ART resistance-conferring K13 mutant in Rwanda, and of other K13 mutations in nearby countries. Herein we confront the prospect of ACT resistance emerging in Africa. In Aim 1, we will test the hypothesis that African Pf strains rarely pose a biological obstacle to K13 mutations driving ART resistance. By gene editing geographically diverse African strains, we will identify the most resistant mutations and assess the impact of the parasite background, which can substantially influence the levels of resistance and fitness. Having recently completed two Pf genetic crosses between Cambodian ART-resistant K13 mutants and the drug-sensitive African parasite NF54, we will map and confirm secondary ART resistance modulators. We will also test whether resistance can be attributed to loss-of-function mutations that restrict hemoglobin endocytosis in early ring stages. In Aim 2, we will test the hypothesis that mutant K13 will exert a substantial fitness cost in African parasites, which could impede its spread in high-transmission settings. One approach will be to quantify growth rates of barcoded K13 mutant and wild-type isogenic lines. We also hypothesize that ART resistance in Asian parasites evolved via a gain of K13 mutations combined with compensatory fitness mutations, and will use our genetic cross progeny to map and confirm fitness modulators. In Aim 3, we will pursue determinants of Pf resistance to the ACT partner drugs PPQ, lumefantrine (LMF), pyronaridine (PND) and amodiaquine (ADQ) in African parasites. Gene editing will be used to test the hypothesis that PPQ resistance can arise through single point mutations in African PfCRT haplotypes. Efforts to identify determinants of resistance to LMF and PND will employ selections with hyper- mutable African lines. We will also leverage the discovery in one of our genetic crosses of a two-component basis of ADQ resistance that includes pfcrt and an unknown determinant on chromosome 12. The identification of these markers will provide a valuable tool to screen for ADQ resistance. This proposal, which aligns with the NIAID priority of supporting research on antimicrobial drug resistance, is designed to proactively prepare for the dire possibility of ART and ACT resistance emerging in Africa by identifying causal determinants and mutations and assessing whether fitness costs can impede the spread of resistance in African transmission settings.

项目概要 基于青蒿素 (ART) 的联合疗法 (ACT) 在全球范围内的采用发挥了重要作用 自 2000 年代初以来，将全球恶性疟原虫 (Pf) 疟疾负担减半；然而，进展已经 自 2015 年以来停滞不前。疟疾的影响仍然巨大，估计 2018 年有 405,000 人死亡。现在，Pf 耐药性 ART 衍生物及其 ACT 伙伴药物可能会压倒控制努力。寄生虫具有抗性 ART 和哌喹 (PPQ) 主要分别由 k13 和 pfcrt 基因突变介导， 席卷了东南亚的低传播环境。非洲 ACT 耐药性的发展 全球 94% 的疟疾负担将是灾难性的。一个主要的警告信号是，一种疾病的日益流行 卢旺达的 ART 抗性 K13 突变体以及附近国家的其他 K13 突变体。在此我们 面对非洲出现的 ACT 耐药性的前景。在目标 1 中，我们将检验以下假设：非洲 Pf 菌株很少对 K13 突变造成 ART 耐药性的生物学障碍。通过地理基因编辑 不同的非洲菌株，我们将确定最具耐药性的突变并评估寄生虫的影响 背景，这可以极大地影响抵抗力和健身水平。最近完成 柬埔寨抗 ART K13 突变体和药物敏感的非洲寄生虫之间的两个 Pf 基因杂交 NF54，我们将绘制并确认辅助 ART 抗性调节剂。我们还将测试阻力是否可以 归因于限制早期环阶段血红蛋白内吞作用的功能丧失突变。在目标 2 中，我们 将检验突变体 K13 会对非洲寄生虫产生巨大的适应性成本的假设，这可能 阻止其在高传播环境中的传播。一种方法是量化带条形码的 K13 的增长率 突变型和野生型等基因系。我们还假设亚洲寄生虫的 ART 抗性是通过 K13 突变的获得与补偿性适应性突变相结合，并将利用我们的遗传杂交后代 绘制并确认健身调节剂。在目标 3 中，我们将寻找 ACT 合作伙伴 Pf 抵抗的决定因素 治疗非洲寄生虫的药物 PPQ、苯芴醇 (LMF)、咯萘啶 (PND) 和阿莫地喹 (ADQ)。基因编辑 将用于检验非洲 PfCRT 中的单点突变可能产生 PPQ 耐药性的假设 单倍型。确定 LMF 和 PND 抗性决定因素的努力将采用具有超 多变的非洲线。我们还将利用在我们的一个二元基因杂交中的发现 ADQ 抗性的基础，包括 pfcrt 和 12 号染色体上的未知决定因素。鉴定 这些标记将为筛选 ADQ 抗性提供有价值的工具。该提案符合 NIAID 优先支持抗菌药物耐药性研究，旨在为应对新冠肺炎疫情做好积极准备。 通过确定因果决定因素和突变，非洲出现 ART 和 ACT 耐药性的可怕可能性 并评估健身成本是否可以阻止非洲传播环境中的耐药性传播。