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：
9913475
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/9913475
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 fitness in vivo individual patient insight 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.

每年有数亿例疟疾病例接受抗疟药治疗有数千亿疟疾寄生虫的个体患者，有必要继续喂养抗疟疾管道和新药以应对抗药性的出现。近年来已经发现了新颖的抗疟疾化合物，具有破坏疟疾Na+稳态的能力寄生虫。其中四个（螺旋罗内酮，吡唑唑胺，二核喹诺酮和一个硫代酮具有）被指定为临床候选药物。值得注意的是，这些药物属于非常不同的化学类别具有独特的药理和活性在疟原虫生命周期的不同阶段。重要的是，一切这些药物显示体内寄生虫的快速清除。对这些化合物中的几种抗性寄生虫具有显示了P型ATPase（PFATP4）中的一系列突变，现在认为这是Na+泵。因此，通过抑制PFATP4涌入Na+被认为是所有这些的共同作用机理化合物。我们过去几年的工作表明，尽管PFATP4中的突变是必要的对所有这些化合物的抗性，它们并不总是足以产生全部抗性。我们已经发现吡唑胺耐药寄生虫具有额外的突变与PFATP4突变结合的抗性，表明对PFATP4的上皮调节成分活动。我们对Na+涌入到寄生虫的生理后果的研究发现了一些戏剧性的变化表明，迄今未知的调节途径被不合适的监管途径寄生虫中的胞质Na+水平。因此，对受影响的分子途径的彻底研究疟疾寄生虫中Na+稳态的破坏既需要，又可能提供进一步的见解指导未来的药物发现和开发。基因编辑和有条件技术的最新技术进步恶性疟原虫中的基因表达使现在可以在前所未有的细节。通过应用这些方法，我们将研究PFATP4在维持Na+和恶性疟原虫的胆固醇稳态。我们将评估抗性相关的表型后果 PFATP4中的突变，研究突变在PFATP4以外的其他影响耐药性中的作用结合PFATP4突变。我们将研究一个假定的质膜胆固醇转运蛋白这受这些新抗疟药的影响。这些研究将提高我们对新分子的理解我们已经证实了作为发育中有效抗疟药的靶标的途径。