Molecular Pathways Affected by Drugs that Disrupt Na+ Homeostasis in Malaria Parasites

破坏疟原虫 Na 稳态的药物影响的分子途径

基本信息

批准号：
9364295
负责人：
AKHIL B VAIDYA
金额：
$ 58.83万
依托单位：
DREXEL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-05-05 至 2022-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9364295
关键词：
ATP phosphohydrolase Affect Alleles Antimalarials Biotinylation CRISPR/Cas technology Carrier Proteins Cell membrane Chemicals Cholesterol Cholesterol Homeostasis Clinical Collaborations Complement Critical Pathways Development Dose Drug resistance Exclusion Exposure to Future Gene Expression Genes Homeostasis Hypersensitivity Investigation Lead Life Cycle Stages Maintenance Malaria Mammalian Cell Mediating Medicine Modeling Molecular Morphology Mutate Mutation Na(+)-K(+)-Exchanging ATPase Names Oral Parasite resistance Parasites Pathway interactions Patients Pharmaceutical Preparations Phase II Clinical Trials Phenotype Physiological Plasmodium Plasmodium falciparum Process Proteins Regulatory Pathway Resistance Role Sodium Source Surveys Technology Ursidae Family Work asexual cholesterol transporters cost drug candidate drug development drug discovery feeding fitness in vivo individual patient insight killings knock-down mutant novel novel therapeutics pharmacophore response

项目摘要

With hundreds of millions of malaria cases being treated with antimalarial drugs each year and with each individual patient bearing hundreds of billions of malaria parasites, it is necessary to continue to feed the antimalarial pipeline with new drugs to counter the likely emergence of resistance. In recent years several novel antimalarial compounds have been discovered with the ability to disrupt Na+ homeostasis in malaria parasites. Four of these (a spiroindolone, a pyrazoleamide, a dihydroisoquinolone, and a thiotriazole) have been designated clinical drug candidates. Remarkably, these drugs belong to very different chemical classes with distinct pharmacophores and activity against different stages of malaria parasite life cycle. Importantly, all these drugs show fast clearance of parasites in vivo. Parasites resistant to several of these compounds have shown a range of mutations within a P-type ATPase, PfATP4, that is now believed to be a Na+ pump. Thus, influx of Na+ through inhibition of PfATP4 is considered to be the common mechanism of action for all these compounds. Our work over the last few years has revealed that, while mutations in PfATP4 are necessary for resistance to all of these compounds, they are not always sufficient to generate the full level of resistance. We have found that pyrazoleamide-resistant parasites bear additional mutations, which are required to impart full resistance in conjunction with PfATP4 mutations, suggesting epistatic regulatory components to PfATP4 activity. Our investigations of physiological consequences of Na+ influx into the parasite have revealed some dramatic changes suggesting a hitherto unknown regulatory pathway that is perturbed by inappropriate cytosolic Na+ levels in the parasite. Therefore, a thorough investigation of molecular pathways affected by disruption of Na+ homeostasis in malaria parasites is both necessary and likely to provide further insights to guide future drug discovery and development. Recent advances in technology for gene editing and conditional gene expression in Plasmodium falciparum make it now possible to unravel these pathways in unprecedented details. By applying these approaches, we will investigate the role of PfATP4 in maintenance of Na+ and cholesterol homeostasis in P. falciparum. We will assess phenotypic consequences of resistance-associated mutations in PfATP4, and study the role of mutations in genes other than PfATP4 that affect drug resistance in combination with PfATP4 mutations. We will investigate a putative plasma membrane cholesterol transporter that is affected by these new antimalarials. These studies will advance our understanding of novel molecular pathways that we have validated as targets for potent antimalarial drugs in development.

每年有数亿疟疾病例接受抗疟药物治疗，并且每年都有数亿疟疾病例接受抗疟药物治疗。个别患者携带数千亿疟疾寄生虫，有必要继续喂养抗疟新药管道，以应对可能出现的耐药性。近年来数新型抗疟化合物被发现能够破坏疟疾中的 Na+ 稳态寄生虫。其中四种（螺吲哚酮、吡唑酰胺、二氢异喹诺酮和硫代三唑）具有被指定为临床候选药物。值得注意的是，这些药物属于截然不同的化学类别对疟疾寄生虫生命周期的不同阶段具有独特的药效团和活性。重要的是，所有这些药物可快速清除体内寄生虫。对其中几种化合物具有抗药性的寄生虫显示了 P 型 ATP 酶 PfATP4 内的一系列突变，现在认为该酶是 Na+ 泵。因此，通过抑制 PfATP4 流入 Na+ 被认为是所有这些药物的共同作用机制化合物。我们过去几年的工作表明，虽然 PfATP4 的突变对于对所有这些化合物的耐药性，它们并不总是足以产生全部的耐药性。我们发现吡唑酰胺抗性寄生虫带有额外的突变，这些突变需要赋予完全耐药性与 PfATP4 突变相关，表明 PfATP4 的上位调节成分活动。我们对 Na+ 流入寄生虫的生理后果的研究揭示了一些巨大的变化表明迄今为止未知的监管途径受到不当行为的干扰寄生虫的胞质 Na+ 水平。因此，对受影响的分子途径进行彻底的研究疟疾寄生虫中 Na+ 稳态的破坏不仅是必要的，而且可能为以下方面提供进一步的见解：指导未来的药物发现和开发。基因编辑和条件技术的最新进展恶性疟原虫中的基因表达使得现在有可能以前所未有的方式解开这些途径细节。通过应用这些方法，我们将研究 PfATP4 在维持 Na+ 和恶性疟原虫中的胆固醇稳态。我们将评估耐药相关的表型后果 PfATP4 突变，并研究 PfATP4 以外基因突变影响耐药性的作用与 PfATP4 突变的组合。我们将研究一种假定的质膜胆固醇转运蛋白受到这些新抗疟药的影响。这些研究将增进我们对新型分子的理解我们已经验证了这些途径是正在开发的有效抗疟药物的目标。