Modeling Neurofibrillary Degeneration

描述(由申请人提供)： 进行性核上性麻痹有其共同的病理特征，神经纤维缠结(NFT)主要由过度磷酸化的tau组成，有许多神经系统疾病，包括阿尔茨海默病、皮质基底膜变性、Pick病以及与17号染色体连锁的额颞痴呆和帕金森病。为了更好地理解NFT形成的机制及其功能影响，我们建立了具有人类tauopathy的形态和生化特征的tau丝的细胞模型。这些模型由人神经胶质瘤[H4]和神经元细胞[BE(2)-M17D]产生的条件转基因细胞组成，其中野生型或突变型tau的转基因生产通过TetOff诱导机制进行调节。初步研究表明，用4-羟基壬醛(HNE)、蛋白酶体或钙蛋白酶抑制剂处理这些细胞可增强二硫键连接的tau聚集体的组装。结果表明，细胞损伤，如氧化应激和蛋白酶的放松调节，可能在NFT的形成中起作用。我们将利用这个细胞模型来揭示各种侮辱诱导tau聚集的分子机制。我们建议的具体目标是：(1)。为了测试与人类tauopathy病因和发病机制有关的因素是否会加剧条件转染体中tau的聚集，(2)。为了确定增强的聚集是否与tau的溶解性/分配、磷酸化、降解和寡聚化的变化有关，(3)。研究这种加剧的tau聚集是否与特定的激酶、蛋白酶和/或蛋白酶体的激活/活性的水平或状态改变有关，以及(4)。研究是否可以通过解除对激酶/蛋白水解酶的调控来阻止加剧的tau聚集体的进展。这一结果可能为合理设计治疗神经原纤维变性的药物提供有价值的信息。

DESCRIPTION (provided by applicant): Progressive supranuclear palsy shares its defining pathologic signature, neurofibrillary tangles (NFT) consisting primarily of hyperphosphorylated tau, with numerous neurological diseases, including Alzheimer's disease, corticobasal degeneration, Pick's disease as well as frontotemporal dementia and Parkinsonism linked to chromosome 17. To improve our understanding of the mechanism underlying NFT formation and its functional impacts we have developed cellular models that produce tau filaments with morphological and biochemical characteristics of human tauopathies. The models consist of conditional transfectants generated from human neuroglioma [H4] and neuronal [BE(2)-M17D] cells in which transgenic production of wild-type or mutant tau is regulated via the TetOff inducible mechanism. Preliminary studies demonstrated that treatment of these cells with 4-hydroxynonneal (HNE), proteosomal or calpain inhibitors enhances the assembly of disulfide-linked tau aggregates. The results suggest that cellular insults such as oxidative stress and deregulation of proteases may play a role in the formation of NFT. We will employ this cellular model to uncover the molecular mechanism underlying tau aggregation induced by various insults. The Specific Aims of our proposal are: (1). To test if factors implicated in the etiology and pathogenesis of human tauopathies exacerbate tau aggregation in conditional transfectants, (2). To determine if the enhanced aggregation is associated with changes in tau solubility/partition, phosphorylation, degradation and oligomerization, (3). To investigate whether such exacerbated tau aggregation is associated with altered level or state of activation/activity of particular kinases, proteases and/or proteasomes, and (4). To study if progression of the exacerbated assembly of tau aggregates can be blocked through deregulating kinases/proteases. The results are likely to provide valuable information for a rational design of therapeutics to treat neurofibrillary degeneration.