Hyperphosphorylated tau as drug target

描述(申请人提供)：阿尔茨海默病(AD)是目前美国500万人中最常见的痴呆症。如果没有有效的预防或治疗措施，预计到2050年，65岁或65岁以上的AD患者数量将达到1350万，每年的护理费用将超过1万亿美元。AD和其他几种破坏性的神经退行性疾病统称为tau病，在这种疾病中，tau蛋白在病理性上过度磷酸化，聚集在神经细胞中的神经原纤维缠结(NFT)中。由此导致的神经元死亡和认知障碍导致AD和其他脊椎病患者神经退行性变的进展。发现抑制形成或溶解预先形成的缠结的小化学物质是一个有吸引力的策略，可能会减缓甚至逆转AD的进展。然而，到目前为止，所有声称的tau聚集抑制剂都是通过靶向非病理性的、非磷酸化的tau来发现的。此外，动物研究表明，缠结可能通过隔离细胞质中过度磷酸化的tau分子而发挥保护作用。因此，从缠结中释放过度磷酸化tau的化学物质实际上可能在临床上是有害的。这些争议背后的原因之一是缺乏一种有效的方法来生产用于基础和翻译研究的过度磷酸化的tau蛋白。我们已经开发了一种系统，通过它可以在大肠杆菌中有效地生产和纯化被GSK3？激酶磷酸化的tau蛋白。利用过度磷酸化的重组tau蛋白作为药物发现的靶点，可以建立与病理生理相关的治疗策略。这一探索性的R21项目将实现三大目标。首先，我们将研究GSK3在体外如何磷酸化tau形成聚集体的分子细节。其次，我们将产生并比较与阿尔茨海默病相关的不同激酶所产生的tau亚型。第三，使用GSK3？磷酸化的tau，我们将建立药物筛选试验，并启动一项先导性研究，以发现能够增强或抑制过度磷酸化tau形成聚集体的小化合物。新奇的东西和前景。这项R21拨款是一个探索性项目，我们使用一种新技术来生产过度磷酸化的tau蛋白。第一次，药物筛选tau聚集将与病理相关的异构体进行，以确定聚集促进剂和抑制物。通过探索这些新领域，该项目将为全面的基础和翻译研究奠定坚实的基础，最终将导致发现新的治疗方案和策略。 公共卫生相关性：阿尔茨海默氏症目前困扰着500多万美国人，给这个国家带来了巨大的经济、情感和社会负担。在这笔赠款中，我们将使用一种新的ZAC技术来生产过度磷酸化的tau蛋白，这种蛋白与阿尔茨海默氏症和其他几种神经退行性疾病的进展密切相关。我们将使用这种蛋白质作为一个新的靶点，以筛选调节过度磷酸化tau聚集倾向的化合物，这最终可能导致一种特定的治疗方案，延缓或阻止阿尔茨海默病患者的认知损害。

DESCRIPTION (provided by applicant): Alzheimer's Disease (AD) is the most prevalent form of dementia that strikes 5 million Americans currently. Without effective prevention or therapeutics, the number of AD patients 65 years or older is projected to reach 13.5 million in 2050, with care costs exceeding 1 trillion dollars per year. AD and several other devastating neurodegenerative disorders are collectively known as tauopathies in which the tau protein becomes pathologically hyperphosphorylated and aggregates into the neurofibrillary tangles (NFT) in neuron cells. The resultant neuronal death and cognitive deficits lead to the progression of neurodegeneration of AD and other tauopathy patients. Discovering small chemicals that inhibit the formation of, or dissolve the pre-formed tangles is an attractive strategy that may mitigate or even revert the progression of AD. However, all of the purported tau aggregation inhibitors thus far have been discovered by targeting the non-pathological, unphosphorylated tau. Furthermore, animal studies suggested that the tangles may exert a protective function by sequestering the cytoplasmic hyperphosphorylated tau molecules. Accordingly, chemicals that liberate hyperphosphorylated tau from the tangles may actually be detrimental clinically. One of the reasons underlying these controversies is the lack of an efficient method that produces hyperphosphorylated tau protein for basic and translational studies. We have developed a system by which the tau protein phosphorylated by the GSK3¿ kinase can be effectively produced and purified in E. coli. Using the hyperphosphorylated recombinant tau protein as the target for drug discovery, pathophysiologically relevant therapeutic strategies can be established. This exploratory R21 project will achieve three major goals. Firstly, we will investigate the molecular details of how GSK3¿-phosphorylated tau forms the aggregate in vitro. Secondly, we will produce and compare tau isoforms resulting from different kinases that have been linked to Alzheimer's Disease. Thirdly, using the GSK3¿-phosphorylated tau, we will establish a drug screening assay and launch a pilot study that will lead to the discovery of small compounds that enhance or inhibit the propensity of hyperphosphorylated tau to form aggregates. Novelties and outlook. This R21 grant is an exploratory project in which we use a novel technology to produce hyperphosphorylated tau protein. For the first time, drug screen for tau aggregation will be conducted with a pathologically relevant isoform to identify both aggregation enhancers and inhibitors. By exploring these new territories, this project will lay a firm foundation for full-fledged basic and translational studies that eventually will lead to the discovery of novel therapeutic regimen and strategy. PUBLIC HEALTH RELEVANCE: Alzheimer's Disease strikes more than 5 million Americans currently and imposes tremendous economical, emotional, and societal burdens to this country. In this grant, we will use a novel ZAC technique to produce hyperphosphorylated tau protein that is intimately linked to the progression of Alzheimer's and several other neurodegenerative diseases. We will use this protein as a novel target to screen for compounds that modulate the propensity of hyperphosphorylated tau to aggregate, which eventually may lead to a specific therapeutic regimen that delays or stops the cognitive impairment of Alzheimer's Disease patients.