INV OF ASTROCYTE CASPASE ACTV & CD40/CD40L SIGNALING INTERACTIONS IN ALZHEIMER?S

星形胶质细胞天冬氨酸蛋白酶活性的 INV

• 批准号: 7959938
• 负责人: TROY T ROHN
• 金额: $ 9.87万
• 依托单位: UNIVERSITY OF IDAHO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7959938
• 关键词: Alzheimer' s Disease; Amyloid; Amyloid beta-Protein; Amyloid beta-Protein Precursor; Animal Model; Apoptosis; Apoptotic; Astrocytes; Axonal Transport; Brain; Caspase; Cleaved cell; Cognition; Computer Retrieval of Information on Scientific Projects Database; Crossbreeding; Cytoskeleton; Data; Deposition; Development; Disease; Event; Funding; Grant; Human; Idaho; In Vitro; Injury; Institution; Laboratories; Lead; Link; Mediating; Memory; Microtubule-Associated Proteins; Modification; Mus; Neurodegenerative Disorders; Neurofibrillary Tangles; Neurons; Pathogenesis; Pathology; Pathway interactions; Peptide Hydrolases; Play; Prevention; Problem behavior; Proteins; Proteolysis; Radial; Research; Research Personnel; Resources; Role; Signal Transduction; Source; Testing; Therapeutic Intervention; Transgenic Mice; United States National Institutes of Health; Upper arm; age related; attenuation; design; improved; in vivo; mouse model; neuron apoptosis; neuronal replacement; neuronal survival; novel; overexpression; prevent; programs; success; tau Proteins

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Brief Background of the problem and hypothesis: Tau is a microtubule-associated protein that stabilizes the neuronal cytoskeleton and functions in vesicular transport and axonal polarity. Pathological alterations in tau are thought to play a causative role in several neurodegenerative disorders, including Alzheimer's disease (AD). In AD, beta-amyloid (A¿) deposition is accompanied by the gradual replacement of the neuronal cytoskeleton with insoluble NFTs that develop following modifications of tau that include hyperphosphorylation and proteolytic cleavage. However, to date the relationship between A¿ deposition and NFTs remains unknown. One possible link between A¿ and NFTs is the aberrant activation of caspases, proteolytic enzymes responsible for the proper execution of programmed cell death or apoptosis. Recent studies have determined that caspase activation may interconnect these two hallmark pathologies. Thus, in the human AD brain our laboratory as well as others have demonstrated the presence of caspase-cleavage products (CCPs) of tau that are associated with markers of NFT formation. Furthermore, caspase-cleaved tau co-localizes with intracellular A¿1-42 in the AD brain and is induced by A¿1-42, in vitro. Collectively, these results indicate that tangles and amyloid are interconnected through a common pathway, namely caspase-mediated proteolysis. To test this hypothesis directly, we propose in the present application to examine the effects of crossing a novel Tg mouse model of AD (3xTg-AD mice) with mice overexpressing the antiapoptotic protein, Bcl-2 (Bcl-2 OE Tg mice). Our overall hypothesis is that progeny of such a cross will show attenuation in caspase activation and prevention in the pathology and behavioral problems associated with 3xTg-AD mice. The specific Aims of the proposal are: Aim 1: To establish a novel transgenic mouse model of AD that overexpresses the antiapoptotic protein, Bcl-2. Preliminary data suggest that caspase cleavage of tau occurs in an age-dependent manner in 3xTg-AD mice. Bcl-2 is powerful anti-apoptotic protein that rescues many types of neurons from apoptosis caused by injury or disease and can enhance neuronal survival during development. In this aim, we test the hypothesis that progeny resulting from crossing these two Tg mice models are viable and properly overexpress A¿, tau and Bcl-2 in an age-dependent manner. Because all subsequent specific aims can only be carried out following the success of this specific aim, we will provide preliminary data to demonstrate the successful crossbreeding and survival of such progeny for at least 24 months. Aim 2: Assess whether overexpression of Bcl-2 will prevent caspase activation, the cleavage of tau and APP and lead to fewer tangle alterations in AD mice. Recent in vitro and in vivo data suggest that caspase activation and subsequent cleavage of tau may be a key event linking A¿ with NFTs in AD. In this aim, we plan to test this hypothesis directly, by determining whether overexpression of an antiapoptotic protein, Bcl-2, prevents caspase activation and NFT formation in an animal model of AD. Aim 3: Determine whether caspases play a role in the turnover of the amyloid precursor protein and tau following the overexpression of Bcl-2 in 3xTg-AD mice. Evidence suggests that both the amyloid precursor protein (APP) and tau are substrates for caspase-mediated cleavage. The overexpression of Bcl-2 and attenuation of caspase activation may lead to alterations in the levels of APP, A¿ and tau in 3xTg-AD mice. We hypothesize that we will observe higher levels of both APP and tau following overexpression of Bcl-2. Aim 4: To determine whether overexpression of Bcl-2 in 3xTg-AD mice improves cognition. An important determinant for this proposal will be to assess not only the pathology but also cognition following overexpression of Bcl-2. Standard Morris or radial arm mazes will be employed in addition to using a novel memory paradigm involving place recognition. Taken together, we believe the design and rationale for this project should allow us to answer whether caspases play an active role in the pathogenesis associated with AD. We believe this to be both an important and timely study that could identify new targets for the treatment of this disease. Results from this proposal may provide impetus to test pharmacological blockade of caspases as a therapeutic intervention in treating AD.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 问题和假设的简要背景： Tau是一种微管相关蛋白，其稳定神经元细胞骨架并在囊泡运输和轴突极性中起作用。 tau蛋白的病理改变被认为在几种神经退行性疾病中起致病作用，包括阿尔茨海默病（AD）。 在AD中，β-淀粉样蛋白（A？）沉积伴随着神经元细胞骨架逐渐被不溶性NFT取代，这些NFT在tau修饰（包括过度磷酸化和蛋白水解裂解）后发展。 然而，迄今为止，A？沉积和NFT之间的关系仍然未知。 一个可能的联系是，NFT是半胱天冬酶的异常激活，半胱天冬酶是负责程序性细胞死亡或凋亡的正确执行的蛋白水解酶。 最近的研究已经确定，半胱天冬酶激活可能互连这两个标志性病理。 因此，在人类AD脑中，我们的实验室以及其他实验室已经证明存在与NFT形成标志物相关的tau的半胱天冬酶切割产物（CCP）。此外，在体外，胱天蛋白酶切割的tau蛋白与AD脑中的细胞内A 1-42共定位，并由A 1-42诱导。 总的来说，这些结果表明，缠结和淀粉样蛋白是通过一个共同的途径，即半胱天冬酶介导的蛋白水解相互联系。 为了直接检验这一假设，我们在本申请中提出检查将AD的新Tg小鼠模型（3xTg-AD小鼠）与过表达抗凋亡蛋白Bcl-2的小鼠（Bcl-2 OE Tg小鼠）杂交的效果。 我们的总体假设是，这种杂交的后代将显示半胱天冬酶激活的减弱和与3xTg-AD小鼠相关的病理和行为问题的预防。 该提案的具体目标是： 目的1：建立抗凋亡蛋白Bcl-2过表达的AD转基因小鼠模型。初步数据表明，在3xTg-AD小鼠中，tau蛋白的半胱天冬酶裂解以年龄依赖性方式发生。 Bcl-2是一种强有力的抗凋亡蛋白，它可以拯救许多类型的神经元免于损伤或疾病引起的凋亡，并可以提高发育过程中神经元的存活率。在这个目标中，我们测试的假设，从交叉这两个Tg小鼠模型产生的后代是可行的，并适当地过表达A？，tau和Bcl-2的年龄依赖性的方式。 由于所有后续的特定目标只能在该特定目标成功后才能进行，因此我们将提供初步数据，以证明成功的杂交育种和此类后代的存活至少24个月。 目标二：评估Bcl-2的过表达是否会阻止胱天蛋白酶的激活，tau和APP的切割，并导致AD小鼠中更少的缠结改变。最近的体外和体内数据表明，半胱天冬酶激活和随后的tau蛋白裂解可能是AD中A？与NFT联系的关键事件。 在这个目标中，我们计划直接测试这一假设，通过确定是否过表达的抗凋亡蛋白Bcl-2，防止在AD的动物模型中的caspase激活和NFT形成。 目标3：确定半胱天冬酶是否在3xTg-AD小鼠中Bcl-2过表达后淀粉样前体蛋白和tau的周转中发挥作用。 有证据表明，淀粉样前体蛋白（APP）和tau蛋白都是半胱天冬酶介导的切割的底物。 Bcl-2的过表达和caspase激活的减弱可能导致3xTg-AD小鼠中APP、A？和tau水平的改变。 我们假设，我们将观察到更高水平的APP和tau后Bcl-2的过表达。 目的4：确定Bcl-2在3xTg-AD小鼠中的过表达是否改善认知。这一建议的一个重要决定因素将是不仅评估病理学，而且评估Bcl-2过表达后的认知。 除了使用涉及位置识别的新型记忆范式外，还将采用标准莫里斯或桡臂迷宫。 综上所述，我们相信这个项目的设计和原理应该使我们能够回答半胱天冬酶是否在与AD相关的发病机制中发挥积极作用。 我们认为这是一项重要而及时的研究，可以确定治疗这种疾病的新靶点。该提案的结果可能为测试半胱天冬酶的药理学阻断作为治疗AD的治疗干预提供动力。