Tau Truncation & Conformation In Alzheimer's Disease Progression

描述(由申请者提供)：Tau经历了一系列离散的形状变化 阿尔茨海默病(AD)中的细丝形成。与这些变化同时发生的是整个分子的磷酸化事件和caspase位点(D421)的切割，这提高了体外tau细丝的形成速度。还发现了明显改变tau分子形状的N-末端截断事件；它们在tau细丝形成和原位成熟过程中出现的时机对于了解修饰的tau、tau聚合物和tau毒性在AD神经退行性变中的作用是重要的。我们假设tau的羧基和氨基末端区域的这种改变将与从非认知损害(NCI)到轻度认知损害(MCI)到AD的认知转变有很好的相关性。我们将在早期阿尔茨海默病的易感脑区验证这一假说如下：1.我们将使用宗教秩序研究(ROS)中获得的脑切片，使用tau的C末端标记进行定量的免疫组织化学分析。具体地说，我们将使用现有的单抗对D421 caspase位点切割之前和之后的事件进行排序，以关联C-末端之间的关系 结果：1.磷酸化事件和半胱氨酸天冬氨酸氨基转移酶裂解结合记忆功能单项检测； 利用EM定位和免疫化学研究，我们将确定哪些PHF/SF群体与Tau-C3结合；3.利用标准蛋白质化学结合质谱学，我们建议在可溶性tau和不溶于十二烷基硫酸钠的phf-tau中确定N末端截断和邻近的磷酸化位点。然后，我们将生产在最丰富的位置切割的tau的特异性抗体；4.新的和现有的抗体将被用于染色从ROS收集的大脑内嗅皮层和海马区的组织切片，以确定tau分子中的哪些氨基酸截断与从NCI-&GT；MCI-&GT；AD的过渡关联最好；5.在项目3中，NFT分期将与Galanin超神经支配和基因表达相关，在项目1的情况下，与内嗅皮层和海马体体积相关。

DESCRIPTION (provided by applicant): Tau undergoes a discrete set of shape changes during filament formation in Alzheimer's disease (AD). Concurrent with these changes are phosphorylation events throughout the molecule and cleavage at a caspase site (D421) that elevates the rate of tau filament formation in vitro. N-terminal truncation events that apparently change the shape of the tau molecule have also been discovered; the timing of their appearance during the course of tau filament formation and maturation in situ is important in understanding the role of modified tau, tau polymers, and tau toxicity in AD neurodegeneration. We hypothesize that such modifications at the carboxy and amino terminal regions of tau will correlate well with the cognitive transition from the non-cognitive impairment (NCI) to mild cognitive impairment (MCI) to AD. We will test this hypothesis in brain regions vulnerable in early AD as follows: 1. We will perform quantitative immunohistochemical analyses using markers of the C-terminus of tau in situ employing brain sections obtained as part of the Religious Orders Study (ROS). Specifically, we will order the events that precede and succeed cleavage of the D421 caspase site using existing monoclonal antibodies to correlate the relationship between C-terminal phosphorylation events and caspase cleavage with individual tests of memory function; 2. Using EM localization and immunochemical studies, we will determine which PHF/SF populations bind to Tau-C3; 3. Using standard protein chemistry coupled with mass spectrometry, we propose to identify N-terminal truncation and adjacent phosphorylation sites in soluble tau and SDS-insoluble PHF-tau. We will then produce antibodies specific for tau cleaved at the most abundant sites; 4. Novel and existing antibodies will be used to stain tissue sections taken from the entorhinal cortices and hippocampi of brains collected by the ROS to determine which of the amino truncations in the tau molecule correlate best with the transition from NCI->MCI->AD; and, 5. NFT staging will be correlated with galanin hyperinnervation and gene expression in Project 3 and with entorhinal cortex and hippocampal volumes in cases from Project 1.