Using a novel mTBI model to investigate phosphorylation dependent common mechanisms in tauopathies

使用新型 mTBI 模型研究 tau蛋白病的磷酸化依赖性常见机制

• 批准号: 10369078
• 负责人: TIMOTHY J EBNER
• 金额: $ 76.73万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10369078
• 关键词: Affect; Age; Alzheimer' s Disease; Antibodies; Biochemical; Brain; CDK5 gene; Calcium; Cells; Cerebral cortex; Cultured Cells; Dementia; Dendritic Spines; Disease; Disease Progression; Electrophysiology (science); Event; Functional disorder; Genes; Goals; Hippocampus (Brain); Human; Image; Impairment; Inclusion Bodies; Knowledge; Label; Mechanics; Mediating; Modeling; Modification; Molecular; Morphology; Mus; Mutation; Neurodegenerative Disorders; Outcome; PHF-1; Pathogenicity; Pathology; Peptides; Phosphorylation; Physiological; Play; Polymers; Post-Translational Protein Processing; Process; Protein Isoforms; Publishing; Recovery; Research Priority; Role; Series; Severities; Signal Transduction; Slice; Synapses; Synaptic plasticity; System; Tauopathies; Testing; Therapeutic; Therapeutic Intervention; Work; base; density; experimental study; human disease; inhibitor; juvenile animal; mild traumatic brain injury; mouse model; neural circuit; novel; postsynaptic; prevent; synaptic function; tau Proteins; tau aggregation; tau phosphorylation; tau-1; therapeutically effective; tool

Alzheimer’s disease (AD) and many related dementias (ADRDs) are tauopathies, characterized by somatodendritic accumulation of tau and intraneuronal inclusion bodies composed of tau species that have undergone extensive post translational modification. Although some disease-specific Tau modifications have been identified, many are conserved across the full range of tauopathies. We do not yet have a deep understanding of the molecular processes that generate these tau protein modifications, or of their functional consequences in promoting pathogenic cascades. This knowledge gap is a major contributor to our current inability to generate effective therapeutic interventions for AD and other tauopathies. The central hypothesis we are testing here is that a range of pathogenic events induce phosphorylation of tau at specific residues, resulting in mislocalization of tau within the cell and subsequent synaptic dysfunctions, and that inhibition of these early tau phosphorylation events will in turn inhibit tau pathologies and associated signaling deficits. This hypothesis is based on our published work, primarily utilizing cultured cell experimental systems. The direct relevance of this mechanism to human disease is further supported by the recent finding that phosphorylation of tau at these same specific residues is an early event preceding tau fibril formation in AD disease progression. Our overall objective here is to test and further refine this hypothesis in a novel mouse model we have developed (MAPT- GR) that expresses all isoforms of human tau at physiologic levels and ratios. We have found that mild traumatic brain injury (mTBI) induces a rapid phosphorylation and somatodendritic mislocalization of the human tau in these mice. Importantly, we can prevent this tau mislocalization by inhibiting phosphorylation. The specific aims are to: 1. Determine the dynamic changes in the subcellular distribution of phosphorylated tau. We will utilize our novel tauopathy model to test the working hypothesis that phosphorylation of tau at specific residues leads to somatodendritic accumulation of tau, tau mislocalization to dendritic spines, and alters micro- components of dendritic spines. 2. Determine the synaptic and circuit dysfunctions associated with the phosphorylation of tau. We will test the working hypothesis that mislocalization of phosphorylated tau to somatodendritic domains and dendritic spines results in synaptic and circuit dysfunction in our model. 3. Identify the impact of inhibiting these early phosphorylation events on tau mislocalization and associated signaling deficits. We will test our working hypothesis that mTBI activates GSK3β and CDK5, which phosphorylate the B and C domain of the tau protein. Expected Outcomes: We expect to identify the early-stage pathologies and dysfunctions caused by phosphorylation of tau and provide proof-of-concept demonstrations of the extent to which these dysfunctions can be prevented by blocking tau phosphorylation at specific residues. Of equal importance, we expect to have optimized a model and experimental platform in which potential therapeutic compounds that target this common disease mechanism can be tested and optimized.

阿尔茨海默病 (AD) 和许多相关痴呆 (ADRD) 属于 tau蛋白病，其特征是 tau 蛋白的体细胞树突积聚和由 tau 蛋白组成的神经元内包涵体 经历了广泛的翻译后修饰。尽管一些疾病特异性 Tau 修饰已 经鉴定，许多在所有 tau蛋白病中都是保守的。我们还没有深入 了解产生这些 tau 蛋白修饰的分子过程或其功能 促进致病级联的后果。这种知识差距是我们当前的一个主要因素 无法对 AD 和其他 tau 蛋白病产生有效的治疗干预措施。我们的中心假设 这里测试的是一系列致病事件会诱导 tau 在特定残基处磷酸化，从而导致 tau 在细胞内的错误定位和随后的突触功能障碍，以及对这些早期突触功能的抑制 tau 磷酸化事件反过来会抑制 tau 病理学和相关信号传导缺陷。这个假设 基于我们已发表的工作，主要利用培养细胞实验系统。直接相关性 最近的发现进一步支持了这种人类疾病的机制，即 tau 在这些位点的磷酸化 相同的特定残基是 AD 疾病进展中 tau 原纤维形成之前的早期事件。我们的整体 这里的目标是在我们开发的新型小鼠模型（MAPT- GR）以生理水平和比例表达人类 tau 蛋白的所有亚型。我们发现轻度创伤 脑损伤 (mTBI) 会导致人类 tau 蛋白快速磷酸化和体细胞树突错位 这些老鼠。重要的是，我们可以通过抑制磷酸化来防止 tau 蛋白错误定位。具体目标 目的是： 1. 确定磷酸化 tau 蛋白亚细胞分布的动态变化。我们将 利用我们的新型 tau 蛋白病模型来测试特定残基上 tau 蛋白磷酸化的工作假设 导致 tau 蛋白体细胞树突积聚、tau 蛋白错位至树突棘，并改变微- 树突棘的组成部分。 2. 确定与相关的突触和电路功能障碍 tau 磷酸化。我们将测试磷酸化 tau 蛋白错误定位的工作假设 在我们的模型中，体细胞树突域和树突棘导致突触和回路功能障碍。 3. 识别 抑制这些早期磷酸化事件对 tau 错误定位和相关的影响 信号缺陷。我们将测试我们的工作假设，即 mTBI 激活 GSK3β 和 CDK5，这 磷酸化 tau 蛋白的 B 和 C 结构域。预期成果：我们希望确定早期阶段 tau 磷酸化引起的病理和功能障碍，并提供概念验证演示 通过阻断特定残基上的 tau 磷酸化可以在多大程度上预防这些功能障碍。 同样重要的是，我们期望优化模型和实验平台，其中潜力 可以测试和优化针对这种常见疾病机制的治疗化合物。