The Role of Caspase-8 in Alzheimer's Disease

描述(摘自申请者的摘要)：阿尔茨海默病(AD)的一个显著特征是细胞凋亡导致的神经元丢失。 细胞凋亡的特征是质膜起泡，核固缩， 和DNA片段化，并由caspase家族激活启动 天冬氨酸蛋白酶。细胞凋亡的启动涉及到一系列 通过蛋白分解将原半胱氨酸天冬氨酸酶激活为活性形式。两位关键成员 这个家族的成员是caspase-8，caspase中最顶端的成员，以及 Caspase-3，通常被称为此 一家人。因为半胱氨酸酶是特定的，在天冬氨酸残基之后裂解，这 产生抗原性不同的caspase裂解产物(Ccp) 因此，代表了切割定点抗体的理想靶点。 利用这种方法，我们设计了一种针对神经细胞fodrin ccps的抗体。 细胞骨架蛋白，并显示这些产物在 阿尔茨海默氏症。因此，虽然在对照组中没有观察到染色， 观察大鼠海马区和内嗅区皮质神经元的标记。 所有AD病例，随着疾病进展而增加。本研究 与其他人一起展示了激活 阿尔茨海默病脑内神经元的凋亡机制。目前，有两个主要的 细胞凋亡途径：caspase-8参与的死亡受体途径 关键启动子作用与线粒体氧化途径 Caspase-9的应激和激活。通过Fas/TNFR诱导细胞死亡 死亡受体超家族由适配蛋白(例如， Fas相关死亡结构域(FADD)和启动caspase(例如，caspase-8)。 在目前的应用中，我们测试死亡受体途径的作用，并 Caspase-8在阿尔茨海默病中的作用研究caspase-8在细胞周期中的作用 阿尔茨海默氏症我们将建议1)发展定点卵裂 抗caspase-8活性片段的抗体；2)表征这些 使用凋亡模型系统的抗体；3)将该抗体与 利用Fodrin CCP抗体确定caspase-8在介导血管紧张素转换酶中的作用 阿尔茨海默病大鼠脑神经元中caspase-3的激活。澄清确切的 参与caspase-3最终激活的凋亡通路将导致 新的、更具特异性的药理靶点的确定 可能对治疗阿尔茨海默病有用的干预措施。

DESCRIPTION (Adapted from applicant's abstract): A prominent feature of Alzheimer's disease (AD) is the loss of neurons by apoptotic cell death. Apoptosis is characterized by plasma membrane blebbing, nuclear condensation, and DNA fragmentation and is initiated by the activation of caspases, a family of aspartate proteases. The initiation of apoptosis involves the sequential activation of pro-caspases to their active form by proteolysis. Two key members of this family are caspase-8, the most apical member of the caspases, and caspase-3 that is commonly referred to as the executioner member of this family. Because caspases are specific, cleaving after aspartic residues, this generates caspase cleavage products (CCPs) that are antigenically distinct and therefore, represent desirable targets for cleavage site-directed antibodies. Using this approach, we designed an antibody to CCPs of fodrin, a neuronal cytoskeleton protein, and showed widespread accumulation of these products in Alzheimer's disease. Thus, while no staining was observed in control cases, labeling of neurons was observed in the hippocampus and entorhinal cortex of all AD cases, which increased as a function of disease progression. This study along with others has demonstrated a prominent role for the activation of apoptotic mechanisms in neurons of the AD brain. Presently, there are two major pathways of apoptosis: the death receptor pathway in which caspase-8 plays a critical initiator role and the mitochondrial pathway involving oxidative stress and activation of caspase-9. Induction of cell death via the Fas/TNFR super family of death receptors is mediated by adapter proteins (e.g., Fas-associated death domain, FADD) and initiation caspases (e.g., caspase-8). In the present application we test the role of the death receptor pathway and caspase-8 in Alzheimer's disease. To examine the role of caspase-8 in Alzheimer's disease we will propose to 1) develop cleavage site-directed antibodies against the active fragments of caspase-8; 2) characterize these antibodies using model systems of apoptosis; 3) use this antibody together with the fodrin CCP antibody to determine the role of caspase-8 in mediating the activation of caspase-3 in neurons of the AD brain. Elucidation of the exact apoptotic pathway involved in the eventual activation of caspase-3 will lead to the identification of newer, more specific targets for pharmacological intervention that may be useful for the treatment of Alzheimer's disease.