Inhibition of Hsp70 ATPase activity reduces tau through the cellular degradation

抑制 Hsp70 ATP 酶活性可通过细胞降解减少 tau 蛋白

• 批准号: 8319903
• 负责人: John Clarence O'Leary
• 金额: $ 3.33万
• 依托单位: UNIVERSITY OF SOUTH FLORIDA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-14 至 2014-04-13
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8319903
• 关键词: ATP Hydrolysis; ATP phosphohydrolase; Accounting; Affect; Alzheimer' s Disease; Amino Acids; Antibodies; Autophagocytosis; Behavioral; Biological Assay; Cell Culture Techniques; Cell model; Cells; Client; Cognition; Complex; Data; Degradation Pathway; Dependovirus; Development; Disease; Exhibits; Frontotemporal Dementia; Future; Genetic; Goals; Hippocampus (Brain); Hydrolysis; Immunohistochemistry; In Vitro; Intervention; Learning; Literature; Measures; Mediating; Memory; Methods; Methylene blue; Modeling; Molecular Chaperones; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Parkinson Disease; Pathway interactions; Pharmaceutical Preparations; Pick Disease of the Brain; Proteins; Regulation; Research; Source; Symptoms; System; Tauopathies; Testing; Therapeutic; Time; Toxic effect; Triage; Western Blotting; aging population; base; brain cell; chaperone machinery; combat; design; high throughput screening; in vivo; inhibitor/antagonist; mouse model; multicatalytic endopeptidase complex; mutant; nervous system disorder; neuron loss; novel strategies; novel therapeutics; overexpression; pleiotropism; prevent; protein degradation; protein misfolding; repaired; research study; tau Proteins; therapeutic target; tool; tool development

DESCRIPTION (provided by applicant): Molecular chaperones are a promising therapeutic target in the treatment of neurological diseases of protein misfolding. This is because of their ability to interact with "client" proteins that become misfolded and aggregate-prone. One of these clients, the microtubule associated protein tau, abnormally aggregates in numerous neurodegenerative diseases termed tauopathies. Some chaperone proteins have shown auspicious results as therapeutic targets in models of tauopathy. However, this study proposes to add to the evidence for Hsp70-mediated interventions for the discovery of compounds that reduce tau levels. The chaperone activity of Hsp70 is powered by the hydrolysis of ATP. Moreover, many pharmacological compounds that modulate the rate of ATP hydrolysis of Hsp70 have been shown to modulate the levels of tau: One compound that was shown to inhibit the ATPase activity of Hsp70 is methylene blue (MB). MB has been shown to reduce tau levels in various models of tauopathy and has been shown to rescue cognition. These data suggest that Hsp70 ATPase modulation may be a viable tool for the development of anti-tau therapies. However, there is vast literature describing the many other interactions and effects of MB. As a result, the current data create a stronger case for MB as a promising therapeutic candidate than for Hsp70's ATPase as a therapeutic target. Strong evidence for Hsp70 as a therapeutic target will allow drug developers to create new compounds that may hold the cure for tauopathies. Thus, we have created new genetics-based tools with which to study this question in order to collect data that will either support or refute the hypothesis. We have created single amino acid mutants of Hsp70 and tested their ATPase and refolding activity as well as their effects on tau levels. One mutation, E175S, on Hsp70 reduces its ATPase activity and refolding activity. Furthermore, it reduces tau levels in cell models of tauopathy. Thus, we have replicated the previous in vitro data that used Hsp70 inhibitor compounds. The objective of this study is to test the hypothesis that the inhibition of Hsp70 ATPase activity degrades tau through the cellular degradation pathways. To achieve this, our design consists of the following specific aims: 1) We will block and activate the proteasome, macroautophagy and chaperone-assisted autophagy pathways in the presence of Hsp70E175S overexpression; 2) We will determine if inhibiting the ATPase activity of Hsp70 reduces tau in vivo and evaluate the therapeutic potential of this strategy. PUBLIC HEALTH RELEVANCE: The protein tau is very important in the normal activities of brain cells. Due to unknown reasons tau loses its normal function and becomes toxic in a large number of neurological diseases. The number of people suffering from these diseases is large and is projected to increase dramatically due to an increase in the aging population. Unfortunately, the current treatments available for most of these diseases only reduce symptoms for a brief period of time. As a result, the discovery of therapies that could halt, prevent or significantly slow the repercussions of tau toxicity is an urgent goal in the scientific field.

描述（由申请人提供）：分子伴侣是治疗蛋白质错误折叠的神经系统疾病的有前景的治疗靶点。这是因为它们能够与“客户”蛋白质相互作用，这些蛋白质变得错误折叠和易于聚集。这些客户之一，微管相关蛋白tau，异常聚集在许多神经退行性疾病称为tau蛋白病。一些伴侣蛋白在tau蛋白病模型中作为治疗靶标显示出良好的结果。然而，这项研究提出增加Hsp 70介导的干预措施的证据，以发现降低tau水平的化合物。Hsp 70的伴侣活性由ATP的水解提供动力。此外，许多调节Hsp 70的ATP水解速率的药理学化合物已显示调节tau的水平：一种显示抑制Hsp 70的ATP酶活性的化合物是亚甲蓝（MB）。MB已显示在各种tau蛋白病模型中降低tau蛋白水平，并已显示挽救认知。这些数据表明，Hsp 70 ATP酶调节可能是开发抗tau疗法的可行工具。然而，有大量文献描述了甲基溴的许多其他相互作用和影响。因此，目前的数据为MB作为一个有前途的治疗候选人比Hsp 70的ATP酶作为一个治疗靶点创建了一个更强的情况。Hsp 70作为治疗靶点的强有力证据将使药物开发人员能够创造出可能治愈tau蛋白病的新化合物。因此，我们创造了新的基于遗传学的工具来研究这个问题，以收集支持或反驳这一假设的数据。我们已经创建了热休克蛋白70的单氨基酸突变体，并测试了它们的ATP酶和重折叠活性以及它们对tau水平的影响。Hsp 70上的一个突变E175 S降低了其ATP酶活性和重折叠活性。此外，它降低了tau蛋白病细胞模型中的tau水平。因此，我们复制了先前使用Hsp 70抑制剂化合物的体外数据。本研究的目的是验证Hsp 70 ATP酶活性抑制通过细胞降解途径降解tau蛋白的假设。为了实现这一目标，我们的设计包括以下具体目标：1）我们将在Hsp 70 E175 S过表达的情况下阻断和激活蛋白酶体、大自噬和分子伴侣辅助的自噬途径; 2）我们将确定抑制Hsp 70的ATP酶活性是否会在体内减少tau蛋白，并评估这种策略的治疗潜力。 公共卫生相关性：tau蛋白在脑细胞的正常活动中非常重要。由于未知的原因，tau蛋白失去了其正常功能，并在大量神经系统疾病中变得有毒。患有这些疾病的人数很多，而且由于人口老龄化的增加，预计还会急剧增加。不幸的是，目前大多数这些疾病的治疗方法只能在短时间内减轻症状。因此，发现可以阻止、预防或显著减缓tau毒性影响的疗法是科学领域的紧迫目标。 领域