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: 7720023
• 负责人: TROY T ROHN
• 金额: $ 7.45万
• 依托单位: UNIVERSITY OF IDAHO
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7720023
• 关键词: Alzheimer' s Disease; Amyloid; Amyloid beta-Protein; Amyloid beta-Protein Precursor; Amyloid deposition; Animal Model; Apoptosis; Apoptotic; Astrocytes; Axonal Transport; Brain; Caspase; Cleaved cell; Cognition; Computer Retrieval of Information on Scientific Projects Database; Crossbreeding; Cytoskeleton; Data; Development; Disease; Endopeptidases; Event; Funding; Grant; Human; In Vitro; Injury; Institution; Laboratories; Lead; Link; Localized; Mediating; Memory; Microtubule-Associated Proteins; Modification; Mus; Neurodegenerative Disorders; Neurofibrillary Tangles; Neurons; Pathogenesis; Pathology; Pathway interactions; Peptide Hydrolases; Play; Prevention; Problem behavior; Protein Overexpression; Proteins; Proteolysis; Radial; Research; Research Personnel; Resources; Role; Signal Transduction; Source; Standards of Weights and Measures; Testing; Therapeutic Intervention; Thinking; Transgenic Organisms; United States National Institutes of Health; Upper arm; age related; attenuation; design; improved; in vivo; mouse model; neuron apoptosis; neuronal survival; novel; prevent; 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.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 问题和假设的简要背景： Tau 是一种微管相关蛋白，可稳定神经元细胞骨架并在囊泡运输和轴突极性中发挥作用。 tau 蛋白的病理改变被认为在包括阿尔茨海默病 (AD) 在内的多种神经退行性疾病中发挥着致病作用。 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，NFT 是在 tau 修饰（包括过度磷酸化和蛋白水解裂解）后形成的。 然而，迄今为止，A¿ 沉积和 NFT 之间的关系仍然未知。 A¿ 和 NFT 之间的一个可能的联系是半胱天冬酶的异常激活，半胱天冬酶是一种蛋白水解酶，负责程序性细胞死亡或细胞凋亡的正确执行。 最近的研究已经确定半胱天冬酶激活可能将这两种标志性病理联系起来。 因此，我们的实验室以及其他实验室已经证明，在人类 AD 大脑中存在与 NFT 形成标记相关的 tau 蛋白半胱天冬酶裂解产物 (CCP)。此外，半胱天冬酶裂解的 tau 蛋白与 AD 大脑中的细胞内 A¿1-42 共定位，并在体外由 A¿1-42 诱导。 总的来说，这些结果表明缠结和淀粉样蛋白通过共同途径（即半胱天冬酶介导的蛋白水解作用）相互关联。 为了直接检验该假设，我们在本申请中建议检查新型AD 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 caspase 激活的减弱，并预防与 3xTg-AD 小鼠相关的病理和行为问题。 该提案的具体目标是： 目的 1：建立过表达抗凋亡蛋白 Bcl-2 的新型 AD 转基因小鼠模型。初步数据表明，在 3xTg-AD 小鼠中，tau 蛋白的 caspase 裂解以年龄依赖性方式发生。 Bcl-2 是一种强大的抗凋亡蛋白，可以拯救多种类型的神经元免于因损伤或疾病引起的凋亡，并可以提高神经元在发育过程中的存活率。为此，我们测试了以下假设：这两种 Tg 小鼠模型杂交产生的后代是可行的，并且以年龄依赖性方式正确过度表达 A¿、tau 和 Bcl-2。 由于所有后续的具体目标只有在该具体目标成功后才能进行，因此我们将提供初步数据来证明此类后代的成功杂交和存活至少24个月。 目标 2：评估 Bcl-2 的过度表达是否会阻止 caspase 激活、tau 和 APP 裂解，并减少 AD 小鼠中的缠结改变。最近的体外和体内数据表明，caspase 激活和随后的 tau 蛋白裂解可能是 AD 中将 A¿ 与 NFT 联系起来的关键事件。 为此，我们计划通过确定抗凋亡蛋白 Bcl-2 的过度表达是否会阻止 AD 动物模型中的 caspase 激活和 NFT 形成来直接检验这一假设。 目标 3：确定 3xTg-AD 小鼠中 Bcl-2 过度表达后，半胱天冬酶是否在淀粉样前体蛋白和 tau 蛋白的周转中发挥作用。 有证据表明淀粉样蛋白前体蛋白 (APP) 和 tau 蛋白都是半胱天冬酶介导的裂解的底物。 Bcl-2 的过度表达和 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 Bcl-2 过度表达后，我们将观察到更高水平的 APP 和 tau。 目标 4：确定 3xTg-AD 小鼠中 Bcl-2 的过度表达是否可以改善认知能力。该提案的一个重要决定因素不仅是评估病理学，还评估 Bcl-2 过度表达后的认知能力。 除了使用涉及地点识别的新颖记忆范例之外，还将使用标准莫里斯或径向臂迷宫。 总而言之，我们相信这个项目的设计和基本原理应该能让我们回答半胱天冬酶是否在 AD 相关的发病机制中发挥积极作用。 我们相信这是一项重要且及时的研究，可以确定治疗这种疾病的新靶点。该提案的结果可能会推动测试半胱天冬酶的药理学阻断作为治疗 AD 的治疗干预措施。