Tau Truncation & Conformation In Alzheimer's Disease Progression

描述（由申请人提供）：Tau在治疗期间经历一组离散的形状变化。 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中的磷酸化事件和半胱天冬酶位点（D421）处的裂解，其提高了体外tau丝形成的速率。还发现了明显改变tau分子形状的N-末端截短事件;在tau细丝形成和原位成熟过程中其出现的时间对于理解修饰的tau、tau聚合物和tau毒性在AD神经变性中的作用是重要的。我们假设tau的羧基和氨基末端区域的这种修饰与从非认知障碍（NCI）到轻度认知障碍（MCI）再到AD的认知转变密切相关。我们将在早期AD易受影响的大脑区域中测试这一假设，如下所示：1。我们将进行定量免疫组织化学分析，使用标记物的C-末端的tau原位采用脑切片作为宗教秩序研究（ROS）的一部分。具体地说，我们将使用现有的单克隆抗体对D421半胱天冬酶位点裂解之前和之后的事件进行排序，以关联C-末端与D421半胱天冬酶位点之间的关系。 磷酸化事件和半胱天冬酶切割与记忆功能的个体测试; 2. 使用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;使用标准的蛋白质化学结合质谱，我们建议确定可溶性tau和SDS不溶性PHF-tau的N-末端截短和相邻的磷酸化位点。然后，我们将产生对在最丰富的位点切割的tau特异性的抗体; 4.将使用新的和现有的抗体对取自通过ROS收集的脑的内嗅皮质和大脑皮层的组织切片进行染色，以确定tau分子中的哪种氨基截短与从NCI->MCI->AD的转变最相关;和在项目3中，NFT分期将与甘丙肽神经支配过度和基因表达相关，在项目1中，NFT分期将与内嗅皮质和海马体积相关。

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.