Molecular pathways affected by drugs that disrupt Na+ and lipid homeostasis in malaria parasites

破坏疟原虫中钠和脂质稳态的药物影响的分子途径

• 批准号: 10659924
• 负责人: AKHIL B VAIDYA
• 金额: $ 71.2万
• 依托单位: DREXEL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-05 至 2027-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10659924
• 关键词: ATP phosphohydrolase; Active Biological Transport; Affect; Antimalarials; Biochemical; Biological; Biology; Carbon; Cell Cycle; Cell membrane; Cells; Chemicals; Cholesterol; Cholesterol Homeostasis; Chromosome Segregation; Clinical Trials; Collection; Complex; Cytolysis; Cytoplasm; DNA metabolism; Development; Drug Targeting; Drug resistance; Enzymes; Event; Exposure to; Fatty Acids; Funding; Genetic; Goals; Homeostasis; Homo; Knowledge; Lipids; Malaria; Membrane; Metabolic; Metabolism; Molecular; Morphology; Parasites; Pathway interactions; Patients; Pediatric Hospitals; Pharmaceutical Preparations; Phase; Phenotype; Philadelphia; Physiology; Plasmodium; Plasmodium falciparum; Play; Process; Protein Dephosphorylation; Protein phosphatase; Proteins; Research Personnel; Role; Signal Transduction; Sodium; Structure; Universities; Work; drug discovery; fatty acid transport; genetic manipulation; inhibitor; insight; interdisciplinary approach; lipid transport; nuclear division; premature; prevent; recruit; response; rhoptry; smoothened signaling pathway

Project Summary In recent years, several chemically diverse compounds have been identified that target PfATP4, a P-type ATPase involved in maintaining Na+ homeostasis in malaria parasites. Some of these compounds have advanced to clinical trials. Thus, PfATP4-active compounds are among the most attractive new antimalarials being developed to counter the continuing threat of drug resistance. Over the previous funding period, we have discovered some dramatic alterations in parasite physiology that accompany a short 2 h exposure to PfATP4 inhibitors. These include: i) Rapid alterations in lipid homeostasis within the parasites with reversible accumulation of cholesterol in the parasite plasma membrane (PPM); ii) Morphological changes resembling premature schizogony; and iii) Massive dephosphorylation of parasite proteins that may underlie the metabolic slowdown that follows PfATP4 inhibition. These observations reveal a collection of hitherto unknown interrelated molecular pathways, disruptions of which result in parasite demise. We found that PfATP4 inhibition appears to result in inhibition of PfNCR1, another druggable transporter, that is involved in maintaining lipid/cholesterol homeostasis within the PPM. Reduction of cholesterol content of the RBC plasma membrane results in dramatic expulsion of trophozoites from the host cell without the lysis of the RBC membrane. Remarkably, treatment with either PfATP4 or PfNCR1 inhibitors prevents this expulsion. These studies suggest an active transport of cholesterol between the RBC plasma membrane and the parasite. We found that trophozoite stage parasites exposed to PfATP4 inhibitors for just 2 h undergo massive morphological changes that resemble premature onset of schizogony events including the formation of inner membrane complexes, rhoptry-like structures and karyokinesis. In addition, trophozoites undergo massive reduction of a large number of metabolites suggestive of metabolic shutdown. We hypothesize that underlying all these events is a signaling cascade unleashed by the influx of Na+ into parasite cytoplasm following PfATP4 inhibition. In support of this proposition, we found dephosphorylation of a large number of proteins, prominent among which were molecules involved in DNA metabolism, chromosome segregation and cell cycle processes. The complexity of events triggered by PfATP4 inhibition requires a multidisciplinary approach. For this purpose, we have recruited outstanding co-investigators in consortium arrangements for the next funding period. Together, we propose to carry out the following specific aims: i) Investigate the relationship between cholesterol dynamics and its role in fatty acid and lipid transport in P. falciparum; ii) Explore the significance of dephosphorylation of proteins that follows PfATP4 inhibition; iii) Examine the causes of metabolic slowdown following PfATP4 inhibition; iv) Derive structural information for PfATP4 and PfNCR1 to understand molecular details about these validated antimalarial drug targets.

项目摘要 近年来，已经确定了几种化学上的化合物，靶PFATP4是P型 ATPase参与疟疾寄生虫中Na+稳态。其中一些化合物有 先进到临床试验。因此，PFATP4活性化合物是最具吸引力的新抗疟药之一 开发以应对持续耐药性威胁。在以前的资金期间，我们有 发现了寄生虫生理的一些戏剧性改变，这些变化伴随着2小时的PFATP4 抑制剂。其中包括：i）可逆的寄生虫内脂质稳态的快速改变 寄生虫质膜（PPM）中胆固醇的积累； ii）类似的形态变化 过早精神分裂； iii）可能是代谢的寄生虫蛋白的大量去磷酸化 PFATP4抑制后的放缓。这些观察结果揭示了迄今未知相互关联的集合 分子途径，破坏导致寄生虫的灭亡。我们发现PFATP4抑制似乎 导致抑制PFNCR1（另一种可药物转运蛋白），该转运蛋白涉及维持脂质/胆固醇 ppm内的稳态。降低RBC质膜的胆固醇含量会导致戏剧性 从宿主细胞中驱动滋养体，而无需裂解RBC膜。值得注意的是，治疗 PFATP4或PFNCR1抑制剂都可以防止这种驱逐。这些研究表明主动运输 RBC质膜和寄生虫之间的胆固醇。我们发现滋养体阶段寄生虫 暴露于PFATP4抑制剂仅2 h，经历了大规模的形态变化，类似于过早 精神分裂事件的发作，包括形成内膜复合物，类似于Rhoptry的结构和 喀林诺尼。此外，滋养体会大量减少大量代谢产物暗示性 代谢关闭。我们假设所有这些事件的基础是信号级联 PFATP4抑制后，Na+流入寄生虫细胞质中。为了支持这个主张，我们发现 大量蛋白质的去磷酸化，其中突出的是参与DNA的分子 代谢，染色体分离和细胞周期过程。 PFATP4触发的事件的复杂性 抑制需要一种多学科的方法。为此，我们招募了出色的共同研究员 在下一个资金期间的财团安排中。一起，我们建议进行以下特定 目的：i）研究胆固醇动力学及其在脂肪酸和脂质转运中的作用之间的关系 恶性疟原虫； ii）探讨遵循PFATP4抑制的蛋白质去磷酸化的重要性； iii） 检查PFATP4抑制后代谢放缓的原因； iv）得出结构信息 PFATP4和PFNCR1了解有关这些经过验证的抗疟药靶标的分子细节。