Activity of Glutamate Transporter GLT1 in CA3 Neurons

CA3 神经元中谷氨酸转运蛋白 GLT1 的活性

• 批准号: 7226344
• 负责人: Melissa R Regan
• 金额: $ 5.27万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7226344
• 关键词: Accounting; Animals; Astrocytes; Biochemical; Brain; Cellular biology; Chromosome Pairing; Data; Development; Excitatory Amino Acid Transporter 2; Excitatory Synapse; Extracellular Space; Glutamate Receptor; Glutamate Transporter; Glutamates; Goals; Hippocampus (Brain); Human; Location; Maintenance; Maps; Messenger RNA; Mus; Nerve Degeneration; Neurons; Play; Protein Isoforms; Pyramidal Cells; Regulation; Reporting; Role; Synapses; Synaptic Transmission; Testing; Time; Transgenic Mice; extracellular; hippocampal pyramidal neuron; mossy fiber; prevent; promoter; research study

DESCRIPTION (provided by applicant): Glutamate transporters in the brain play at least two critical roles at excitatory synapses: maintenance of low extracellular glutamate levels, which supports normal activation of glutamate receptors and prevents excitotoxic degeneration of neurons, and modulation of the concentration time course of glutamate in the extracellular space. Five glutamate transporter isoforms have been identified, of which GLT-1 (termed EAAT2 in human) accounts for up to 95% of total glutamate transport activity. In the normal CNS, GLT-1 protein is largely restricted to astrocytes where it plays a dominant role in clearing extrasynaptic glutamate. Evidence for neuronal expression of GLT-1 mRNA, as well as biochemical and electrophysiological data suggesting the presence of pre-synaptic transporters, has been reported, but there has been no strong evidence of functional GLT-1 protein in neurons. To examine the biology of cell-specific transporter regulation, I generated GLT1-BAC-promoter transgenic mice. Using these animals, we have now identified GLT-1 promoter activity, and, subsequently, glutamate transporter currents, selectively in mouse hippocampal CAS neurons. The goals of this proposal are to establish the identity and subcellular location of the GLT-1 transporter in CAS neurons, to investigate regulation of its expression, and to assess its potential role in synaptic transmission. These experiments will begin to directly test the functional significance of GLT-1 in neurons.

描述（由申请人提供）：大脑中的谷氨酸转运蛋白在兴奋性突触中至少发挥两个关键作用：维持低细胞外谷氨酸水平，支持谷氨酸受体的正常激活并防止神经元的兴奋性毒性变性，以及调节细胞外空间中谷氨酸的浓度时间过程。已鉴定出五种谷氨酸转运蛋白亚型，其中 GLT-1（在人类中称为 EAAT2）占总谷氨酸转运活性的 95%。在正常的中枢神经系统中，GLT-1 蛋白主要局限于星形胶质细胞，在清除突触外谷氨酸方面发挥主导作用。已有报道表明神经元表达 GLT-1 mRNA，以及生化和电生理学数据表明存在突触前转运蛋白，但尚无强有力的证据表明神经元中存在功能性 GLT-1 蛋白。为了研究细胞特异性转运蛋白调节的生物学特性，我培育了 GLT1-BAC 启动子转基因小鼠。利用这些动物，我们现在已经选择性地鉴定了小鼠海马 CAS 神经元中的 GLT-1 启动子活性，以及​​随后的谷氨酸转运蛋白电流。 该提案的目标是确定 CAS 神经元中 GLT-1 转运蛋白的身份和亚细胞位置，研究其表达的调节，并评估其在突触传递中的潜在作用。这些实验将开始直接测试 GLT-1 在神经元中的功能意义。