Characterization of a caspase-cleavage resistant tau knock-in mouse

半胱天冬酶裂解抗性 tau 敲入小鼠的表征

基本信息

批准号：
9142543
负责人：
LUCIANO D'ADAMIO
金额：
$ 14.76万
依托单位：
ALBERT EINSTEIN COLLEGE OF MEDICINE, INC
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-04-15 至 2017-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9142543
关键词：
Adopted Age Alzheimer&apos s Disease Amyloid Amyloid beta-Protein Amyloid beta-Protein Precursor Amyloid deposition Animal Model Antibodies Asparagine Back Behavioral Biological Brain C-terminal Caspase Cerebrum Cleaved cell Clinical Trials Codon Nucleotides Cognitive deficits Collection Cytoskeletal Proteins Data Defect Dementia Deposition Development Disease Progression Exons Failure Filament Genetic Health Human Impaired cognition Indiana Knock-in Mouse Knock-out Lead Learning Link Mediating Memory Memory impairment Modeling Molecular Mus Mutate Mutation Nerve Degeneration Neurodegenerative Disorders Neurofibrillary Tangles Neurons Outcome PHF-1 Pathogenesis Pathology Patients Peptides Physiology Play Process Protein Isoforms Protein Precursors Proteins Regulation Resistance Role Senile Plaques Short-Term Memory Synapses Synaptic plasticity Tauopathies Testing Therapeutic Intervention Toxic effect Transgenic Mice Transgenic Organisms V717F age related amyloid peptide amyloid precursor protein processing beta-site APP cleaving enzyme 1 drug discovery extracellular familial Alzheimer disease feeding interest mouse model mutant neurofibrillary tangle formation neuron loss presenilin prevent promoter secretase tau Proteins tau expression tau mutation theories treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is the most common cause of ageing-dependent dementia in the world and is associated with cerebral amyloid plaques and neurofibrillary tangles (NFTs). Amyloid plaques are mostly composed of Aß peptides while NFTs are composed of abnormal aggregates of hyperphosphorylated forms of the cytoskeletal protein tau. Aß peptides are produced by a double cleavage of the amyloid precursor protein (APP). BACE1 cleavage produces the C-terminal fragment, ß-CTF, which is then processed into several Aß isoforms by γ-secretase. Genetic data suggest that regulation of APP processing contributes to AD. Current drug discovery approaches in AD have focused on preventing Aß formation or removing existing amyloid deposits. The repeated failures of compounds/biologics targeting amyloid in clinical trials can either be attributed to the inclusion of AD patients who were too advanced in their disease progression to benefit from therapeutic intervention, or to the fact that Aß is not the main cause of AD patho-physiology. The most advanced alternative hypothesis of AD is that of tau toxicity. Consistent with this hypothesis, reducing endogenous tau expression prevents behavioral deficits in transgenic mice expressing human APP with familial AD mutations, without altering Aß levels. Our preliminary data indicate that tau also mediates behavioral deficits in Familial Danish Dementia (FDDKI mice), an AD-like dementia associated with mutations in the regulator of APP processing BRI2/ITM2B, also characterized by tauopathy. Some evidence suggests that caspases are activated early in the progression of AD and may play a role in neuronal loss and NFT pathology. Tau is cleaved at D421 (ΔTau) by executioner caspases. Following caspase-cleavage, ΔTau facilitates nucleation-dependent filament formation and adopts a conformational change recognized by MC1, an early pathological tau marker. ΔTau can be phosphorylated and recognized by the NFT antibody PHF-1. In AD brains, ΔTau associates with markers of NFTs and correlates with cognitive decline. Furthermore, ΔTau initiates NFT formation and can exert toxic effects. These findings have led to the hypothesis that ΔTau is a critical toxic moiety underlying neurodegeneration. To directly test this theory, we have generated knock-in mice in which the endogenous tau codon GAC in exon 12, encoding for D421, has been mutated into AAC, which now encodes for an asparagine (N). These knock-in mice, called TauD421N, express a tau mutant, taucas/res that cannot be cleaved by caspases and therefore cannot generate ΔTau. TauD421N mice will be used to determine whether ΔTau mediates synaptic plasticity and memory deficits in animal models of AD and FDD, two neurodegenerative disorders in which tau plays a pathogenic role. Our studies will speak to whether modulation of ΔTau formation is a potential strategy for the treatment of AD and other neurodegenerative disorders mediated by neuro-toxic tau forms.

描述（由适用提供）：阿尔茨海默氏病（AD）是世界上依赖痴呆症的最常见原因，与脑淀粉样蛋白斑块和神经纤维纤维缠结（NFTS）有关。淀粉样蛋白斑块主要由Aß辣椒组成，而NFTs由细胞骨架蛋白TAU的高磷酸化形式的异常聚集体组成。 AßPepperides是由淀粉样蛋白前体蛋白（APP）的双重切割产生的。 BACE1裂解产生C末端片段β-CTF，然后通过γ-分泌酶将其处理成几种Aß同工型。遗传数据表明，对应用程序处理的调节有助于AD。当前的AD药物发现方法集中于防止Aß形成或去除现有的淀粉样蛋白沉积物。在临床试验中靶向淀粉样蛋白的化合物/生物制剂的反复失败可以归因于我们在其疾病进展中无法从治疗干预中受益的AD患者，或者aß不是AD病理生理学的主要原因。 AD的最先进的替代假设是TAU毒性。与这一假设一致，减少内源性TAU表达可防止具有家庭AD突变表达人类应用的转基因小鼠的行为缺陷，而不会改变Aß水平。我们的初步数据表明，tau还介导了丹麦家族性痴呆症（FDDKI小鼠）的行为，这是一种与App Processing Bri2/ITM2B的突变相关的AD样性痴呆，也以Tauopathy为特征。一些证据表明，在AD的进展中，Cassaps被激活，并可能在神经元丧失和NFT病理学中发挥作用。 tau被execution子caspase在D421（ΔTAU）上裂解。 caspase切割后，ΔTAU促进了核依赖性细丝的形成，并适应了早期病理TAU标记MC1认可的协商变化。 ΔTAU可以被NFT抗体PHF-1磷酸化和识别。在AD大脑中，ΔTAU与NFT的标记相关，并与认知能力下降相关。此外，Δtau启动NFT形成并可以执行毒性作用。这些发现导致了以下假设：ΔTAU是一种关键的有毒部分神经变性。为了直接检验该理论，我们生成了敲门型小鼠，其中外显子GAC在第12个外显子GAC（编码D421）已被突变为AAC，该AAC现在编码了天冬酰胺（n）。这些称为taud421n的敲击小鼠表达了一个tau突变体，taucas/res不能被caspase裂解，因此无法产生Δtau。 TAUD421N小鼠将用于确定ΔTAU介导突触可塑性和记忆是否在AD和FDD的动物模型中定义了两种神经退行性疾病，其中TAU起致病作用。我们的研究将表明，调节ΔTAU形成是否是治疗AD和其他神经退行性疾病的潜在策略，该疾病是由神经毒性TAU形式介导的。