Anatomical Changes in Tau Transgenic Models

Tau 转基因模型的解剖学变化

• 批准号: 8139760
• 负责人: BRADLEY T. HYMAN
• 金额: $ 43.67万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-30 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8139760
• 关键词: Alzheimer' s Disease; Animals; Apoptosis; Apoptotic; Automobile Driving; Biological Models; Caspase; Cells; Cessation of life; Characteristics; Clinical; Clinical Trials; Data; Defect; Dementia; Disease; Distress; Doxycycline; Drug Industry; Environment; Gene Expression; Gene Transfer; Generations; Genes; Hippocampus (Brain); Hour; Human; Image; Imaging Techniques; Immediate-Early Genes; Individual; Kinetics; Lesion; Life; Membrane; Methods; Microscopic; Microscopy; Mitochondria; Modeling; Molecular; Mus; Mutation; Neurobiology; Neurofibrillary Tangles; Neuronal Dysfunction; Neurons; Pathway interactions; Pharmaceutical Preparations; Phase; Phenotype; Phosphorylation; Phosphotransferases; Physiological; Property; Propidium Diiodide; Response Elements; Role; Severities; Site; Stimulus; Structure; Symptoms; System; Tauopathies; Techniques; Testing; Tetanus Helper Peptide; Therapeutic Agents; Time; Tissues; Toxic effect; Transgenes; Transgenic Mice; Transgenic Model; Wild Type Mouse; base; design; environmental enrichment for laboratory animals; hTau Mice; hyperphosphorylated tau; in vivo; killings; life history; mouse model; neurofibrillary tangle formation; neuron loss; neuronal cell body; overexpression; prevent; public health relevance; relating to nervous system; research study; response; tau Proteins; tau aggregation; tau mutation; tau phosphorylation; therapeutic target; thioflavine; tomography; vector

DESCRIPTION (provided by applicant): Neurofibrillary tangles are one of the primary hallmarks of Alzheimer disease, and closely correlate with clinical severity. They consist of hyperphosphorylated tau that aggregates in the neuronal cell body. Cross sectional histological studies suggest that tangles kill neurons. Tau disaggregation is thus a major target of the pharmaceutical industry, with at least one drug already in human clinical trials. However, recent data suggest that tangles may not be toxic. We propose to test an alternative hypothesis, in which soluble tau induced toxicity leads to activation of apoptosis related cascades, followed by tangle formation. In order to test this model, we have developed in vivo multiphoton based longitudinal imaging techniques for tangles, caspase activation, and propidium iodide (a marker of loss of membrane integrity). Aim 1 applies this approach to Tg4510 P301L tau mice that develop NFT and neuronal loss. Surprisingly, we see caspase activation that appears to precede and predict tangle formation. We will also use array tomography, an advanced microscopic method using ultrathin sections of tissue, to determine the characteristics of the caspase positive, tangle negative cells to test the hypothesis that kinase activation leads to phosphorylation of tau, and that caspase activation leads to the truncation of tau -the combination of which causes tau aggregation into a tangle. We will use gene transfer and pharmacological studies to further dissect this pathway, to ask whether caspase activation, and caspase truncation of tau, are necessary or sufficient to cause tangle formation, neuronal distress or death. Aim 2 asks if NFT remain in viable cells and are long lived, or if they are toxic to the neurons in which they are found either in terms of structure or function. These experiments take advantage of the power of longitudinal in vivo multiphoton imaging to follow the fate of individual tangle bearing neurons for weeks to months. We will also test the hypothesis that tangle bearing neurons are excluded from participation in normal neural system activation from physiological stimuli by exposing animals to an enriched environment, then examining individual neurons in hippocampal subfields for immediate early gene (Arc) expression and the presence or absence of tangles. Aim 3 will rigorously test the hypothesis that wild type, nonmutant tau, undergoes similar phenomenon and that the toxic effects of tau over expression are due, in large part, to soluble tau. We take advantage of 3 models: examination of an alternative transgenic model, the hTau mice which express a minigene of wild type human tau (on a tau null background), introduction of wild type tau (or truncated forms of tau) into wild type mice using gene transfer approaches with AAV2 gene vectors, and the Tg4510 mice, which harbor a tet-response element driving the tau gene. These models allow comparison of wild type and mutant tau, and will also allow us to distinguish te effects of soluble tau from those of misfolded or aggregated tau. Taken together, our proposed studies will test the hypotheses that a non-tangle related mechanism of tau toxicity initiates apoptotic cascades, and that tangles may be a relatively nontoxic, long lived species. The results will have direct impact on design of therapeutic agents destined for clinical trials. PUBLIC HEALTH RELEVANCE: Neurofibrillary tangles are widely believed to be the cause of neuronal death in Alzheimer disease, and so the cause of the dementia symptoms that mark this common and devastating disease. The current application will examine the molecular and temporal relationships between neurofibrillary tangles, neuronal death and neuronal dysfunction using advanced microscopy methods and model systems. Based on these results, therapies aimed at reducing the damage done by neurofibrillary tangles will be explored, in an attempt to better understand what causes the damage and how to prevent it.

描述（由申请人提供）：神经纤维缠结是阿尔茨海默氏病的主要标志之一，与临床严重程度密切相关。它们由聚集在神经元细胞体中的高磷酸化tau组成。横截面组织学研究表明缠结杀死神经元。因此，TAU分解是制药行业的主要目标，在人类临床试验中至少已经有一种药物。但是，最近的数据表明缠结可能没有毒性。我们建议检验另一种假设，其中可溶性TAU诱导的毒性导致与凋亡相关的级联反应激活，然后缠结形成。为了测试此模型，我们开发了用于缠结，caspase激活和碘化丙啶的基于体内多光子的纵向成像技术（膜完整性丧失的标志）。 AIM 1将这种方法应用于发展NFT和神经元损失的TG4510 P301L TAU小鼠。令人惊讶的是，我们看到胱天冬酶激活似乎是在缠结形成之前的。我们还将使用阵列层析成像，一种使用组织的超薄切片的高级显微镜方法来确定caspase阳性，缠结阴性细胞的特征，以检验以下假说，即激酶激活导致tau的磷酸化导致caspase激活导致Tau tau的脱孔导致Tau的脱孔 - 导致Tau tau contelegention tanu tanu contemation tanu contemation tanu contemegation tanu tange contemegation tane contemation contemention tane contementigation。我们将使用基因转移和药理学研究进一步剖析这一途径，以询问caspase激活和tau的胱天蛋白酶截断是必要的还是足以引起缠结形成，神经元遇险或死亡的必要或足够的。 AIM 2询问NFT是否保留在可行的细胞中并且长期存在，或者它们是否对在结构或功能方面发现的神经元有毒。这些实验利用了体内多光子成像的纵向力量，以遵循单个缠结神经元的命运，数周至几个月。我们还将检验以下假设：缠结神经元被排除在参与正常神经系统从生理刺激中的激活，通过将动物暴露于富集的环境中，然后检查海马子场中的单个神经元即时早期基因（ARC）表达（ARC）表达和存在或不存在。 AIM 3将严格检验以下假设：野生型，非mutant tau经历了类似的现象，并且Tau对表达的毒性作用在很大程度上归因于可溶性tau。我们利用了3种模型：替代转基因模型的检查，即表达野生型人tau的小鼠（在tau null背景上），使用AAV2基因载体和TG4510小鼠的野生型tau（或截短的tau形式）将野生型Tau（或Tau的截短形式）引入野生型小鼠，并构成了taus tae tae taet-response-response tae-response-response-response-response response response response response response response response response response response response response response response。这些模型可以比较野生型和突变体tau，还可以使我们能够将可溶性tau的TE效应与错误折叠或聚集的Tau区分开。综上所述，我们提出的研究将检验以下假设：tau毒性的无危险机理会引起凋亡的级联反应，并且缠结可能是一种相对无毒的长期生存的物种。结果将直接影响注定要进行临床试验的治疗剂的设计。 公共卫生相关性：广泛认为神经原纤维缠结是阿尔茨海默氏病神经元死亡的原因，因此是痴呆症状的原因，标志着这种常见和毁灭性疾病。当前的应用将使用高级显微镜方法和模型系统研究神经原纤维缠结，神经元死亡和神经元功能障碍之间的分子和时间关系。基于这些结果，将探讨旨在减少神经纤维缠结造成的损害的疗法，以便更好地了解导致损害以及如何预防损害的方法。