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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.

每年有数以亿计的疟疾病例得到抗疟药物的治疗