Astrocyte-synapse interactions in a rat model of Alexander disease

项目摘要 亚历山大病（AxD）是一种致命的神经退行性疾病， 星形胶质细胞酸性蛋白（GFAP）是星形胶质细胞的主要中间纤维，可导致蛋白质聚集 和星形胶质细胞反应AxD分为两种亚型，I型患者更严重 早期发病，认知和运动延迟，癫痫发作，发育不良。现有的鼠标模型具有 在阐明AxD星形胶质细胞病理学的途径和机制中是不可或缺的，但显示出最小的临床意义。 与人类疾病相比，我们开发了一种新的GFAP突变大鼠模型， 出生后第三周后急剧下降，初步数据显示， 以及成年动物的运动损伤和神经元的潜在损失。这种新模式提供了独特的 有机会研究异常星形胶质细胞-神经元相互作用在AxD中的作用，特别是 关于突触和神经元数量。在具体目标1中，我们将确定星形胶质细胞何时开始对 突变GFAP和是否这符合蛋白质聚集通过分子和超微结构 分析. GFAP病理学对星形胶质细胞成熟和存活的影响将通过定量分析来评估。 出生后发育过程中的神经胶质细胞浸润以及幼年和成年大鼠中的星形胶质细胞数量。在特定 目的2，我们将研究星形胶质细胞病理对出生后突触发生和神经元存活的影响 通过量化突触的形成、成熟和消除，以及幼年和幼年期神经元的数量， 成年动物为了进一步确定星形胶质细胞功能障碍对AxD神经元的影响，我们将进行 用急性分离的星形胶质细胞（Aim 1）和神经元（Aim 2）在不同的阶段进行转录谱分析。 疾病发展。这些数据将用于评估突触发生线索和炎症反应的平衡。 和保护途径，并与突触支持中正常星形胶质细胞功能的潜在丧失相关， 在整个疾病进展过程中。在特定目标3中，将对幼龄动物进行试验，以确定是否 认知和运动障碍在严重临床表型发作之前是明显的。最后我们将 使用反义技术来测试在早期和晚期阶段的神经元和认知表型的拯救。 GFAP抑制的疾病。这项工作将确定发病机制的新特点，提高我们的 了解神经元的继发性变化，并在不同的时间点测试这些表型的可逆性。 疾病的阶段。

Project Summary Alexander disease (AxD) is a fatal neurodegenerative disease caused by mutations in the gene for glial fibrillary acidic protein (GFAP), the major intermediate filament of astrocytes, which lead to protein aggregation and a reactive astrocyte response. AxD is classified into two subtypes, with the more severe Type I patients having early onset with cognitive and motor delays, seizures, and failure to thrive. Existing mouse models have been integral in elucidating pathways and mechanisms in AxD astrocyte pathology, but display minimal clinical deficits compared to the human disease. We have developed a new GFAP mutant rat model that exhibits precipitous decline just after the third postnatal week, and preliminary data demonstrate significant cognitive and motor impairment and the potential loss of neurons in adult animals. This new model offers unique opportunities to investigate the contribution of abnormal astrocyte-neuron interaction in AxD, particularly with respect to synapses and neuron number. In Specific Aim 1, we will determine when astrocytes begin to react to mutant GFAP and whether this coincides with protein aggregation through both molecular and ultrastructural analysis. The effects of GFAP pathology on astrocyte maturation and survival will be assessed by quantifying neuropil infiltration during postnatal development, and astrocyte numbers in juvenile and adult rats. In Specific Aim 2, we will examine the effects of astrocyte pathology on postnatal synaptogenesis and neuronal survival by quantifying synapse formation, maturation, and elimination, as well as numbers of neurons in juvenile and adult animals. To further define the effects of astrocyte dysfunction on neurons in AxD, we will perform transcription profiling with acutely isolated astrocytes (Aim 1) and neurons (Aim 2) at different stages of disease development. These data will be used to assess synaptogenic cues and the balance of inflammatory and protective pathways, and to correlate the potential loss of normal astrocyte functions in synaptic support throughout disease progression. In Specific Aim 3, juvenile animals will be tested to determine whether cognitive and motor impairment are apparent before the onset of severe clinical phenotypes. Finally, we will use antisense technology to test rescue of neuronal and cognitive phenotypes at early and late stages of disease by GFAP suppression. This work will identify new features of pathogenesis, improve our understanding of the secondary changes in neurons, and test the reversibility of these phenotypes at different stages of disease.