Excitotoxic Signaling in HD Transgenic Neurons

HD 转基因神经元中的兴奋毒性信号传导

• 批准号: 6685929
• 负责人: KARI RENE HOYT
• 金额: $ 21.02万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-12-15 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6685929
• 关键词: Huntington' s disease; NMDA receptors; adenosine triphosphate; apoptosis; calcium binding protein; calcium channel blockers; calcium indicator; calcium ion; enzyme activity; gene dosage; gene mutation; genetically modified animals; glutamate receptor; immunofluorescence technique; membrane potentials; mitochondrial disease /disorder; neurons; neurotoxins; oxidative stress; pathologic process; receptor expression; stainings; tissue /cell culture

DESCRIPTION (provided by the applicant): Huntington's disease (HD) is a hereditary neurodegenerative disease characterized by selective basal ganglia damage and movement disorders. The genetic defect responsible for HD is an expanded poly-glutamine repeat in the huntingtin protein in excess of that found in unaffected individuals. The mechanism by which the expanded poly-glutamine repeats in huntingtin causes neuronal degeneration and motor dysfunction is unknown. Based on findings in HD patients and animal models of HD it has been suggested that the genetic defect leads to metabolic compromise with consequent increased sensitivity to glutamate-induced neuronal injury (excitotoxicity). This excitotoxic injury may involve elevated levels of [Ca2+] mitochondrial dysfunction and oxidative stress. Recently, several transgenic mouse models of HD (HDTg) which express the mutant huntingtin gene have been created and exhibit neurologic symptoms and pathology similar to that seen in HD. Recent results from this laboratory and others suggest that HDTg mice do have deficits in metabolic enzyme activity and that neuronal responses to glutamate receptor activation are substantially altered by the expression of the mutant huntingtin protein. We propose to test the hypothesis that mutant huntingtin expression leads to mitochondrial dysfunction and ionotropic glutamate receptor mediated neurotoxicity. This glutamatergic dysfunction may be a consequence of alterations in neuronal metabolism or direct effects on receptor function caused by mutant huntingtin expression. As a model of HD, we will use fluorescence imaging techniques in primary neurons cultured from HDTg mice and their non-transgenic (WT) littermates to test this hypothesis. Our specific aims are to identify the mechanism(s) underlying the potentiation of 1) Glutamate-receptor mediated [Ca2]i responses in HDTg neurons. 2) Glutamate-receptor stimulated mitochondrial depolarization in HDTg neurons. 3) Excitotoxic neuronal death in HDTg neurons. These studies address our long-term goal of evaluating the role of metabolic compromise on glutamate toxicity as it relates to the neuronal dysfunction and death evident in HD. The cell culture models of HD proposed in this work should also provide a convenient means for testing relevant therapies for HD.

描述（申请人提供）：亨廷顿氏病（HD）是 以选择性基底神经节为特征的遗传神经退行性疾病 损害和运动障碍。负责HD的遗传缺陷是 在Huntingtin蛋白中膨胀的多谷氨酰胺重复超出该蛋白 在未受影响的个体中发现。扩展的机制 亨廷顿蛋白中的多谷氨酰胺重复引起神经元变性和运动 功能障碍是未知的。基于高清患者的发现和动物模型 HD已经提出遗传缺陷导致代谢妥协 因此，对谷氨酸诱导的神经元损伤的敏感性提高了 （兴奋性）。这种兴奋性损伤可能涉及[Ca2+]的水平升高 线粒体功能障碍和氧化应激。最近，几个转基因 表达突变体亨廷顿基因的HD的小鼠模型（HDTG）已经 创建并表现出类似于所见的神经系统症状和病理 高清。该实验室和其他人的最新结果表明HDTG小鼠会做 存在代谢酶活性的缺陷，并且神经元反应 谷氨酸受体激活通过表达显着改变 突变的亨廷顿蛋白。我们建议检验突变体的假设 亨廷顿的表达导致线粒体功能障碍和离子型 谷氨酸受体介导的神经毒性。这种谷氨酸能功能障碍可能 是神经元代谢改变或直接影响的结果 由突变亨廷汀表达引起的受体功能。作为高清模型，我们 将在HDTG培养的初级神经元中使用荧光成像技术 小鼠及其非转基因（WT）同窝仔检验这一假设。我们的 具体目的是确定增强力的基础机制 1）HDTG神经元中介导的[Ca2] I反应。 2） 谷氨酸受体刺激HDTG神经元中的线粒体去极化。 3） HDTG神经元中的兴奋性神经元死亡。这些研究解决了我们的长期 评估代谢妥协对谷氨酸毒性的作用的目标 与HD中明显的神经元功能障碍和死亡有关。细胞培养 这项工作中提出的高清模型还应为 测试有关高清的相关疗法。