Therapeutic Expression of Glial Glutamate Transporters

描述（由申请人提供）：星形胶质转运体GLT-1/EAAT2在前脑中负责谷氨酸转运的最大比例。EAAT2的异常表达/功能在散发性ALS、该疾病的转基因模型以及其他神经损伤中都很常见。转运体解除管制的机制尚不完全清楚，但可能涉及启动子激活的改变。我们假设调节这些蛋白的表达可以提供有效的治疗方法来延缓疾病的进展。初步研究提供了令人兴奋的证据，增加EAAT2蛋白/活性可以延缓ALS动物模型的神经退行性变；减少与癫痫相关的癫痫发作，并延缓脑肿瘤的生长。在本提案中，我们将使用最近生成的GLT1和glast启动子报告小鼠来评估转运蛋白的调控。这些啮齿动物将被用于研究神经退行性疾病中转运蛋白的失调。我们建议改变转运蛋白基因激活作为延缓神经退行性疾病的新手段。这些研究的完成将全面了解转运蛋白在正常和异常中枢神经系统中的调节及其作为神经保护剂的潜力。具体建议：1)通过分析GLAST-BAC和GLT1-BAC启动子报告子表达转基因小鼠，了解星形胶质细胞谷氨酸转运体基因表达的正常区域和时间调控；2)验证神经损伤中谷氨酸转运蛋白表达改变是启动子解除调控的结果；3)确定星形胶质细胞谷氨酸转运体表达的改变是否能预防神经元变性。使用能够增加GLT1和GLAST启动子表达的药物，我们将确定星形胶质转运蛋白表达的增加是否可以预防体内神经损伤，我们将通过肌萎缩性侧索硬化症动物模型确定谷氨酸转运的细胞特异性表达是否会改变慢性神经变性。我们假设过表达GLT1或GLAST在疾病模型中具有神经保护作用。总体意义：在本提案中，我们将对GLAST和GLT I的表达有一个基本的了解，发现可以改变谷氨酸转运蛋白活性的试剂，并确定这些方法是否对慢性神经损伤有用。

DESCRIPTION (provided by applicant): The astroglial transporter GLT-1/EAAT2 is responsible for the largest percentage of glutamate transport in forebrain. Abnormal expression/function of EAAT2 is common to sporadic ALS, to transgenic models of the disease, as well as other neurological injuries. The mechanism that underlies transporter deregulation is not fully understood, but may involve altered promoter activation. We hypothesize that regulating expression of these proteins could provide powerful therapies to retard disease progression. Initial studies provide exciting evidence that increasing EAAT2 protein/activity can retard neurodegeneration in ALS animal models; diminish seizures associated with epilepsy, and retard brain tumor growth. In this proposal we will use recently generated GLT1 and GLAST-promoter reporter mice to evaluate the regulation of transporters. These rodents will be used to study the dysregulation of transporters in neurodegenerative disease. We propose to alter transporter gene activation as a novel means to delay neurodegenerative disease. The completion of these studies will provide a comprehensive understanding of transporter regulation in normal and abnormal CNS and their potential as neuroprotectants. Specifically we propose: 1) To understand the normal regional and temporal regulation of astroglial glutamate transporter gene expression, thru analysis of GLAST-BAC and GLT1-BAC promoter reporter expressing transgenic mice; 2) To test the hypothesis that altered glutamate transporter expression in neurological injury is the result of promoter deregulation; 3) To determine if altered cellular expression of astroglial glutamate transporters can prevent neuronal degeneration. Using drugs capable of increasing GLT1 and GLAST promoter expression we will determine if increased expression of the astroglial transporter(s) can prevent neural injury in vivo and we will determine if cell specific expression of glutamate transport alters chronic neurodegeneration using an animal model of amyotrophic lateral sclerosis. We hypothesize that over expression of GLT1 or GLAST will be neuroprotective in disease models. Over all Significance: In this proposal, we will develop a basic understanding of expression of GLAST and GLT I, discover reagents that can alter glutamate transporter activity, and determine if these approaches are useful for chronic neurological insults.