AMPA/Kainate Receptors, Free Radicals, And Motor Neuron Injury

AMPA/红藻氨酸受体、自由基和运动神经元损伤

• 批准号: 7038660
• 负责人: JOHN H WEISS
• 金额: $ 34.31万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7038660
• 关键词: AMPA receptors; calcium channel; calcium flux; fluorescent dye /probe; free radical oxygen; genetically modified animals; glutamate receptor; laboratory mouse; membrane potentials; mitochondrial membrane; motor neurons; nerve injury; oxidative stress; polymerase chain reaction; protein protein interaction; stainings; superoxide dismutase; tissue /cell culture

DESCRIPTION (provided by applicant): Observations of increased CSF glutamate in ALS, together with findings that motor neurons (MNs) are selectively vulnerable to glutamate receptor mediated ("excitotoxic") injury support an excitotoxic contribution to MN loss in the disease. Past studies have highlighted factors that may underlie this vulnerability; in comparison to most other neurons, excitotoxic activation of MNs induces greater mitochondrial Ca2+ overload and exceptionally strong reactive oxygen species (ROS) generation. However, while astroglial glutamate transporters account for most glutamate uptake in the CMS, and their damage appears to underlie extracellular glutamate elevations in ALS, the reason for their dysfunction has been unclear. Providing a possible clue, recent studies suggest that this ROS generated within MNs in response to excitotoxic activation may in itself cause disruption of glutamate uptake in surrounding astrocytes. These observations suggest a mechanism that causatively links excitotoxic MN damage with oxidative disruption of glutamate transport, and provide the basis the for a feed forward model of ALS, in which a range of inciting factors could lead into a common disease pathway. The broad aim of this proposal is to use culture and slice models to extend these studies and further examine the hypothesis that ROS generation within MNs contributes to the loss of regional glutamate transport in vivo. Excitotoxic ROS generation within MNs and its ability to penetrate surrounding tissue and disrupt glutamate transport will be examined in dissociated and slice culture models from wild type mice as well as mice harboring superoxide dismutase (SOD) mutations associated with familial forms of ALS (which provide the best animal models of the disease). SOD mutant mice will be used to examine the degree to which oxidative changes and disruption of transport occurs in regions immediately surrounding large ventral horn MNs, as would be predicted if the MNs are the source of the ROS. Finally, the ability of selected pharmacological interventions to decrease these pathological processes will be tested in slice and animal models. It is hoped that these studies will further clarify sequences of events culminating in selective MN loss in ALS, and thereby facilitate development of new treatment strategies.

描述（由申请人提供）：ALS中CSF谷氨酸增加的观察结果，以及运动神经元（MN）选择性易受谷氨酸受体介导的（“兴奋性毒性”）损伤的发现，支持了兴奋性毒性对疾病中MN损失的贡献。过去的研究已经强调了可能导致这种脆弱性的因素;与大多数其他神经元相比，MN的兴奋性毒性激活诱导更大的线粒体Ca 2+过载和异常强烈的活性氧（ROS）生成。然而，虽然星形胶质细胞谷氨酸转运蛋白占CMS中的大多数谷氨酸摄取，并且它们的损伤似乎是ALS中细胞外谷氨酸升高的基础，但它们功能障碍的原因尚不清楚。提供了一个可能的线索，最近的研究表明，这种ROS内产生的MNs在兴奋性毒性激活本身可能会导致周围的星形胶质细胞谷氨酸摄取中断。这些观察结果表明，兴奋性毒性MN损伤与谷氨酸转运的氧化破坏之间存在因果关系，并为ALS的前馈模型提供了基础，其中一系列激发因素可能导致共同的疾病途径。这个建议的主要目的是使用文化和切片模型来扩展这些研究，并进一步研究的假设，即ROS的产生在MN有助于在体内的区域谷氨酸转运的损失。将在来自野生型小鼠以及携带与ALS家族形式相关的超氧化物歧化酶（SOD）突变的小鼠（其提供了该疾病的最佳动物模型）的解离和切片培养模型中检查MN内的兴奋性毒性ROS产生及其渗透周围组织和破坏谷氨酸转运的能力。将使用SOD突变小鼠来检查在紧邻大腹角MN的区域中发生氧化变化和运输中断的程度，如果MN是ROS的来源，则可以预测。最后，将在切片和动物模型中测试选定的药理学干预减少这些病理过程的能力。希望这些研究将进一步阐明ALS中导致选择性MN丢失的事件序列，从而促进新治疗策略的开发。