Hyperphosphorylated tau as drug target

描述（由申请人提供）：阿尔茨海默病（AD）是目前影响500万美国人的最普遍的痴呆症形式。如果没有有效的预防或治疗方法，预计到2050年，65岁及以上的阿尔茨海默病患者人数将达到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，其中tau蛋白发生病理性过度磷酸化并聚集成神经元细胞中的神经原纤维缠结（NFT）。由此产生的神经元死亡和认知缺陷导致AD和其他牛头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种有吸引力的策略，可以减轻甚至恢复AD的进展。然而，迄今为止，所有声称的tau聚集抑制剂都是通过靶向非病理性，未磷酸化的tau而发现的。此外，动物研究表明，缠结可能通过隔离细胞质过度磷酸化的tau分子发挥保护功能。因此，从缠结中释放过度磷酸化的tau蛋白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产生高磷酸化的tau蛋白用于基础和转化研究。我们已经开发了一种系统，通过该系统可以在大肠杆菌中有效地产生和纯化被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。这个探索性的R21项目将实现三个主要目标。首先，我们将研究GSK3 -磷酸化tau蛋白如何在体外形成聚集体的分子细节。其次，我们将产生并比较由与阿尔茨海默病有关的不同激酶产生的tau亚型。第三，利用GSK3 -磷酸化的tau，我们将建立药物筛选试验，并启动一项试点研究，这将导致发现增强或抑制过度磷酸化的tau形成聚集体的倾向的小化合物。新奇和前景。这项R21资助是一个探索性项目，我们使用一种新技术来生产过度磷酸化的tau蛋白。这是第一次，对tau聚集的药物筛选将与病理相关的异构体进行，以确定聚集增强剂和抑制剂。通过探索这些新领域，该项目将为成熟的基础和转化研究奠定坚实的基础，最终将导致新的治疗方案和策略的发现。

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.