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: 6621466
• 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 2004-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6621466
• 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（由申请人提供）：亨廷顿舞蹈病（HD）是一种 以选择性基底神经节为特征的遗传性神经退行性疾病 损伤和运动障碍。导致 HD 的遗传缺陷是 亨廷顿蛋白中扩展的多聚谷氨酰胺重复序列超过 在未受影响的个体中发现。扩大的机制 亨廷顿蛋白中的聚谷氨酰胺重复序列会导致神经元变性和运动能力 功能障碍未知。基于 HD 患者和动物模型的研究结果 HD 有人认为遗传缺陷会导致代谢受损 从而增加对谷氨酸诱导的神经元损伤的敏感性 （兴奋毒性）。这种兴奋性毒性损伤可能涉及 [Ca2+] 水平升高 线粒体功能障碍和氧化应激。最近，一些转基因 表达突变亨廷顿基因的 HD 小鼠模型 (HDTg) 产生并表现出与以下情况相似的神经症状和病理学： 高清。该实验室和其他实验室的最新结果表明 HDTg 小鼠确实 代谢酶活性和神经元反应有缺陷 谷氨酸受体的激活显着改变的表达 突变型亨廷顿蛋白。我们建议检验突变体的假设 亨廷顿蛋白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 亨廷顿蛋白突变表达引起的受体功能。作为高清的典范，我们 将在 HDTg 培养的原代神经元中使用荧光成像技术 小鼠及其非转基因（WT）同窝小鼠来检验这一假设。我们的 具体目标是确定增强作用的潜在机制 1) HDTg 神经元中谷氨酸受体介导的 [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 神经元中的兴奋毒性神经元死亡。这些研究解决了我们的长期问题 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 HD 模型也应该为 测试 HD 的相关疗法。