Progression of Tau Pathology in AD

描述(申请人提供)：神经原纤维缠结(NFT)主要在阿尔茨海默病(AD)大脑中高度脆弱的长投射神经元中发现。胆碱能基底前脑(CBF)的胆碱能神经元非常容易形成NFT，细胞的一系列变化与缠结形成有关。然而，微管相关tau蛋白形成这些损伤的分子事件仍不清楚。对tau原构体体外组装成细丝的研究有力地表明，tau从可溶形式到纤维形式的转变部分是由磷酸化和C-末端截断完成的，部分是由caspase的作用完成的。此外，沉积在颗粒泡变性小体(GVD)中的酪蛋白激酶1(CK1)磷酸激酶家族的亚型在终末期AD中上调10-30倍。 我们建议确定这些tau改变的出现顺序与胆碱能基底前脑(CBF)长投射神经元中NFT形成的相关性。我们假设，纤维状病变的形成是由一系列可定义的分子事件引起的，这些事件通过磷酸化和截断直接影响tau-S组装能力。我们将通过实现以下特定目标来验证这一假说：1.使用针对特定tau磷酸肽的抗体，我们建议确定CBF神经元是否表现出与从非认知功能障碍(NCI)到轻度认知功能障碍(MCI)、早期和终末期阿尔茨海默病(AD)的转变相关的位点特异性磷酸化事件的进展；2.我们建议使用针对D421(caspase位点)和E 391(AD中另一个已知的截断位点)的抗体来确定C-末端tau截断的进展；3.使用抗CKIpha、CK1和CKIepsilon的抗体，我们将检测从NCI-GT；MCI-&GT；AD；和，4.利用基因芯片技术，我们将检测上述临床诊断患者单个CBF神经元中CK1信息的相对数量和Caspase信息的数量。

DESCRIPTION (provided by applicant): The Neurofibrillary Tangles (NFTs) are found mainly in highly vulnerable long projection neurons in the Alzheimer's disease (AD) brain. The cholinergic neurons of the cholinergic basal forebrain (CBF) are exquisitely prone to NFT formation, and a progression of cellular changes is associated with tangle formation. However, the molecular events that underlie the formation of these lesions by the microtubule-associated tau protein remain unknown. Studies on the in vitro assembly of tau protomers into filaments strongly suggest that tau's transition from the soluble to the fibrillar form can be driven, in part, by phosphorylation and by C-terminal truncation accomplished in part by the action of caspases. Additionally, isoforms of the casein kinase 1 (CK1) phosphokinase family that deposit in granulovacuolar degeneration bodies (GVDs) are upregulated 10-30 fold in end stage AD. We propose to determine the order of appearance of these tau alterations in correlation with NFT formation in the cholinergic basal forebrain (CBF) long projection neurons. We hypothesize that the formation of the fibrillar pathologies is induced by a definable sequence of molecular events that directly impact tau "s assembly competency through phosphorylation and truncation. We will test this hypothesis by accomplishing the following specific aims: 1. Using antibodies against specific tau phosphopeptides, we propose to determine whether CBF neurons exhibit a progression of site-specific phosphorylation events that correlates with the transition from non-cognitive impairment (NCI), to mild cognitive impairment (MCI), early, and end-stage Alzheimer's disease (AD); 2. We propose to determine the progression of C-terminal tau truncation using well-characterized antibodies to D421 (the caspase site) and E 391 (another truncation site known to occur in AD); 3. Using antibodies to CKIalpha, CK1delta, and CKIepsilon, we will assay for the appearance of GVD bodies in CBF neurons during the progression from NCI-->MCI-->AD; and, 4. Using gene array technology, we propose to determine the relative quantities of CK1 message and the amounts of caspase message in individual CBF neurons from patients with the aforementioned clinical diagnoses.