Modeling Neurofibrillary Degeneration

描述（由申请人提供）： 进行性核上性麻痹与许多神经系统疾病（包括阿尔茨海默病、皮质基底节变性、皮克病以及与17号染色体相关的额颞叶痴呆和帕金森综合征）共享其定义性病理特征，即主要由过度磷酸化的tau组成的神经系统缠结（NFT）。为了提高我们对NFT形成及其功能影响的机制的理解，我们开发了产生具有人类tau蛋白病的形态学和生物化学特征的tau丝的细胞模型。该模型由从人神经胶质瘤[H4]和神经元[BE（2）-M17 D]细胞产生的条件转染子组成，其中野生型或突变型tau的转基因产生通过TetOff诱导机制调节。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增强了二硫键连接的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失调可能在NFT的形成中发挥作用。我们将采用这种细胞模型来揭示各种损伤诱导的tau蛋白聚集的分子机制。我们建议的具体目标是：（1）。为了测试人类tau蛋白病的病因学和发病机制中涉及的因素是否加剧条件转染子中的tau聚集，（2）。为了确定增强的聚集是否与tau溶解度/分配、磷酸化、降解和寡聚化的变化相关（3）。研究这种加剧的tau聚集是否与特定激酶、蛋白酶和/或蛋白酶体的活化/活性的改变的水平或状态相关，和（4）。研究tau聚集体加剧组装的进展是否可以通过解除激酶/蛋白酶的调节来阻断。这些结果可能为合理设计治疗神经退行性变的疗法提供有价值的信息。

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.