MECHANISMS FOR GLUTAMATE TRANSPORTER ALTERATIONS IN ALZH

说明（改编自申请人的摘要）：谷氨酸是哺乳动物中枢神经系统中主要的兴奋性神经递质。谷氨酸通常通过位于神经元和神经胶质中的高亲和力钠依赖性谷氨酸转运体从突触间隙清除。谷氨酸转运功能障碍可导致突触中过量谷氨酸的积累，随后产生神经毒性。EAAT 2是一种星形胶质细胞谷氨酸转运蛋白，是主要的谷氨酸转运蛋白。在阿尔茨海默病（AD）和肌萎缩侧索硬化症（ALS）的受影响区域发现了这种蛋白质的丢失。反义敲除研究以及EAAT2缺失小鼠已经证明EAAT2蛋白的缺失可以导致兴奋毒性神经元变性。在这些神经退行性疾病中，EAAT 2蛋白的选择性丢失是什么原因？研究人员最近在ALS中的研究表明，EAAT 2的丢失是由于异常mRNA，可能是异常剪接的结果。在这项研究中，它提出了测试的可能性，异常的mRNA可以解释在AD的EAAT 2的损失。 初步结果表明，AD标本中存在异常EAAT2 mRNA。研究者将确定异常EAAT 2 mRNA种类的丰度，并评价AD患者中异常EAAT 2 mRNA的患病率以及它们是否与EAAT 2蛋白丢失相关。研究者还提出研究在具有APP（淀粉样前体蛋白）突变的转基因小鼠中是否存在异常EAAT 2 mRNA。异常EAAT2 mRNA是否会导致EAAT2蛋白丢失并导致体内神经退行性变？为了回答这个问题，他们将产生转基因小鼠，表现出星形胶质细胞特异性表达的人野生型和异常EAAT 2 mRNA。是什么机制导致了这些异常的剪接缺陷？他们将确定EAAT2基因中是否存在获得性体细胞突变。 研究者建议从AD脑中培养星形胶质细胞，并确定是否可以在体外产生异常EAAT 2 mRNA。

DESCRIPTION (Adapted from applicant's abstract):.Glutamate is the predominant excitatory neurotransmitter in the mammalian central nervous system. Glutamate is normally cleared from the synaptic cleft by high-affinity, sodium-dependent glutamate transporters located in both neurons and glia. Glutamate transport malfunction can lead to the accumulation of excessive glutamate in the synapse, with subsequent neurotoxicity. EAAT2 is an astroglial glutamate transporter and is the predominant glutamate transporter. A loss of this protein has been found in the affected areas of Alzheimer's disease (AD) as well as in amyotrophic lateral sclerosis (ALS). Antisense knockdown studies as well as EAAT2 null mice have demonstrated that loss of EAAT2 protein can lead to excitotoxic neuronal degeneration. What could account for the selective loss of EAAT2 protein in these neurodegenerative diseases? The investigator's recent studies in ALS have demonstrated that the loss of EAAT2 is due to aberrant mRNAs, possibly as a consequence of abnormal splicing. In this study it is proposed to test the possibility that the aberrant mRNAs could account for the loss of EAAT2 in AD. Preliminary results demonstrate that aberrant EAAT2 mRNAs are present in AD specimens. The investigator will determine the abundance of the aberrant EAAT2 mRNA species and evaluate the prevalence of the aberrant EAAT2 mRNAs in AD patients and whether they are correlated with loss of EAAT2 protein. The investigator also proposes to investigate whether there are aberrant EAAT2 mRNAs in transgenic mice with APP (amyloid precursor protein) mutations. Can aberrant EAAT2 mRNAs lead to loss of EAAT2 protein and contribute to neurodegeneration in vivo? To answer this they will generate transgenic mice manifesting astrocyte-specific expression of the human wild-type and aberrant EAAT2 mRNAs. What mechanism accounts for these aberrant splicing defects? They will determine whether there are acquired somatic mutations in the EAAT2 gene. The investigator proposes to develop astrocyte cultures from AD brain and determine if the aberrant EAAT2 mRNAs can be produced in vitro.