Development of Zebrafish Taupoathy Models for Translational Research

描述（由申请人提供）：这项工作的长期目标是开发进行性核上性麻痹（PSP）和皮质基底变性（CBD）的有效治疗方法。这些常见的神经退行性疾病与明显的运动和认知异常有关，预后差（中位生存期6 - 8年），因为目前的治疗不能预防疾病进展。这两种疾病的特征都是神经元丢失和微管相关蛋白Tau （4R- Tau）在整个中枢神经系统神经元中4重复异构体异常聚集体的积累。据认为，4R-Tau是这些疾病发病机制的核心：(i)编码Tau的MAPT基因突变（例如P301L）可引起PSP和CBD表型；（ii） PSP和CBD与MAPT位点的遗传变异密切相关。为了解决开发针对Tau积累及其在体内神经元中的影响的药物进展的关键障碍，我们建议开发斑马鱼Tau病模型，该模型可用于药物发现工作，对假定治疗剂进行快速比较测试，并研究确定新的治疗靶点。我们的初步研究表明，在中枢神经系统神经元中表达人类4R-Tau基因的转基因斑马鱼出现了与人类疾病相似的进行性神经表型、脑萎缩、Tau过度磷酸化和亲银沉积。在这些初步研究中，选择了具有早发表型的转基因系，因为它们具有组成性的转基因表达。在这个探索性的建议中，我们将采用条件表达方法来开发增强型斑马鱼tau病模型，该模型的表型异常发生得足够早，以便在多孔板格式的药物发现工作和比较疗效研究中发挥最大作用。在Aim 1中，我们将使用基于Gal4/UAS的两部分系统，允许4R-Tau在CNS神经元中高水平表达，而不选择建立具有早发表型的细胞系。我们将产生WT或P301L突变体在UAS增强子下表达人类4R-Tau的转基因动物，并使用我们构建的新型Gal4驱动系在中枢神经系统中广泛反式激活Tau表达。在Aim 2中，我们将确定表达人类Tau蛋白的斑马鱼幼虫是否有条件地表现出生存受损、运动或动眼肌缺陷，以及这些表型是否可用于药物发现分析。在Aim 3中，我们将确定表达人类Tau的斑马鱼幼虫是否有条件地表现出Tau超磷酸化、神经原纤维缠结形成或神经元死亡的证据，以及这是否可以在体内成像。这些新的转基因品系将为转化研究开发PSP和CBD的新疗法，以及潜在的其他tau病如阿尔茨海默病和慢性头部损伤提供有价值的工具。我们未来的工作将利用这些模型进行药物发现和开发，包括早期的发现工作和后期的优化研究，将这些疾病的新治疗方法引入神经病学临床。

DESCRIPTION (provided by applicant): The long-term aim of this work is to develop effective treatments for progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). These common neurodegenerative diseases are associated with prominent motor and cognitive abnormalities and have a poor prognosis (median survival 6 - 8 years) because current treatments do not prevent disease progression. Both diseases are characterized by neuronal loss and accumulation of abnormal aggregates of the 4-repeat isoform of the microtubule-associated protein Tau (4R- Tau) in neurons throughout the CNS. It is thought that 4R-Tau is central to the pathogenesis of these disorders: (i) mutations (e.g. P301L) in the MAPT gene encoding Tau can give rise to PSP and CBD phenocopies; (ii) PSP and CBD are strongly associated with genetic variants at the MAPT locus. In order to address a critical barrier to progress in developing drugs to target Tau accumulation and its consequences in neurons in vivo, we propose to develop zebrafish Tauopathy models that are optimized for drug discovery efforts, rapid comparative testing of putative therapeutic agents, and studies to identify novel therapeutic targets. Our preliminary studies showed that transgenic zebrafish expressing a human 4R-Tau transgene in CNS neurons developed progressive neurological phenotypes, brain atrophy, Tau hyperphosphorylation and argyrophilic deposits, similar to the human diseases. In these preliminary studies, transgenic lines with early- onset phenotypes were selected against, because of constitutive transgene expression. In this exploratory proposal, we will employ a conditional expression approach to develop enhanced zebrafish Tauopathy models with phenotypic abnormalities occurring sufficiently early to be maximally useful for drug discovery efforts and comparative efficacy studies in multiwell plate formats. In Aim 1, we will use a bipartite system based on Gal4/UAS to allow expression of 4R-Tau at high levels in CNS neurons, without selecting against the establishment of lines with early-onset phenotypes. We will generate transgenic animals in which WT or P301L mutant human 4R-Tau is expressed under a UAS enhancer, and use novel Gal4 driver lines we have constructed to trans-activate Tau expression widely in the CNS. In Aim 2, we will determine whether zebrafish larvae expressing human Tau conditionally show impaired survival, motor or oculomotor deficits, and whether these phenotypes could be used as drug discovery assays. In Aim 3, we will determine whether zebrafish larvae expressing human Tau conditionally show evidence of Tau hyper-phosphorylation, neurofibrillary tangle formation or neuronal death, and whether this can be imaged in vivo. These novel transgenic lines will be a valuable tool for translational studies to develop new therapies for PSP and CBD, and potentially other Tauopathies such as Alzheimer's disease and chronic head injury. Our future work will exploit these models for drug discovery and development, both early-phase discovery efforts and later optimization studies, to bring new treatments for these disorders into the neurology clinic.