NEUROPATHOLOGY AND PATHOGENESIS OF HUNTINGTON' DISEASE

亨廷顿病的神经病理学和发病机制

• 批准号: 6457452
• 负责人: ANTON J. REINER
• 金额: $ 6.11万
• 依托单位: UNIVERSITY OF TENNESSEE HEALTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-15 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6457452
• 关键词: AMPA receptors; Huntington's disease; Saimiri; calcium flux; corpus striatum; genetically modified animals; human tissue; interneurons; laboratory mouse; laboratory rat; neural degeneration; neuropathology; neuropharmacology; neurotoxins; pathologic process; polymerase chain reaction

DESCRIPTION: (Verbatim from the Applicant's Abstract) This is a competing continuation of NS 28721. In this upcoming 5-year project, the applicant will examine the hypothesis that Huntington's disease (HD) is caused by AMPA receptor (AMPAR)-mediated excitotoxicity. He proposes that the HD gene defect leads to selective striatal neuronal death by 1) enrichment in AMPARs and cortical inputs in striatal projection neurons and parvalbuminergic interneurons in HD. 2) A preponderance of GluR2 containing AMPARs in striatal neurons projecting to the internal pallidal segment accounts for their lesser vulnerability in HD and 3) The HD mutation decreases the numbers of group II mGluRs on corticostriatal terminals, thereby increasing cortical activation and excitotoxicity of striatal neurons. The main hypotheses are based on the following observations: a. The HD gene product is widely expressed in the brain, whereas the neurons killed in HD are localized to the striatum b. No cell-type specific proteins that interact with HD proteins are specific to vulnerable striatal neurons. c. The level of huntingtin in a given type of striatal neuron does not seem to correlate with vulnerability. d. There is suggestion that in HD transgenic mice (Bates R6/2), group II mGluRs are downregulated and that sEPSP frequency is increased. e. HD pathology can be reproduced by 3-NP and by quinolinic acid administration f. Neurons that die are rich in cortical input. g. Neurons that die are rich in AMPARs, some of which appear to be more deficient in GluR2 (the GluR2 hypothesis). From these observations, the applicant concludes "the HD mutation may render corticostriatal neurons destructive rather than render striatal neurons vulnerable." These hypotheses will be tested in 5 Specific Aims: Aim 1: Use single cell RT-PCR, immunoprecipitation and LM and EM immunolabeling to characterize the abundance and subunit composition of AMPA receptors present on HD-vulnerable and HD-resistant striatal interneuron and projection neuron types in rats. Aim 2: Characterize differences between striatal interneurons and projection neurons in AMPAR mediated synaptic responses to cortical input and in subunit dependent AMPA physiology (Ca permeability, rectification and desensitization) in rats Aim 3: Pharmacologically characterize the role of AMPARs and mGluR2/3-regulatable corticostriatal glutamate release in the selective death of striatal neurons in rats chronically administered 3NP, a model of HD. Aim 4: Use in-situ hybridization histochemistry, LM and EM immuno to determine in striatal neurons in monkey and in HD striatum whether the distribution of AMPAR subunits in HD vulnerable and HD resistant striatal neurons is consistent with their hypothesized role in selective neurodegeneration. Aim 5: Use in-situ hybridization histochemistry, LM and EM immuno to determine in a transgenic rat model of HD and in human HD specimens whether or not the HD mutation decreases mGluR2/3 in corticostriatal neurons and their intrastriatal terminals.

描述：（逐字摘自申请人摘要）这是一个竞争性的 NS 28721 的延续。在这个即将到来的 5 年项目中，申请人将 检查亨廷顿病 (HD) 是由 AMPA 引起的假设 受体（AMPAR）介导的兴奋性毒性。他提出HD基因缺陷 通过以下方式导致选择性纹状体神经元死亡：1) AMPARs 富集和 纹状体投射神经元和小白蛋白能的皮质输入 高清中间神经元。 2）纹状体中含有AMPAR的GluR2占优势 投射到内部苍白球段的神经元占其较小的比例 HD 中的脆弱性和 3) HD 突变减少了 II 组的数量 皮质纹状体末梢上的 mGluR，从而增加皮质激活和 纹状体神经元的兴奋毒性。 主要假设基于以下观察： 一个。 HD基因产物在大脑中广泛表达，而神经元 HD 中死亡的区域局限于纹状体 b.与 HD 蛋白相互作用的细胞类型特异性蛋白不具有特异性 到脆弱的纹状体神经元。 c.特定类型纹状体神经元中亨廷顿蛋白的水平似乎并不 与脆弱性相关。 d.有人建议，在 HD 转基因小鼠 (Bates R6/2) 中，II 组 mGluRs 被下调并且 sEPSP 频率增加。 e. HD 病理学可以通过 3-NP 和喹啉酸给药来重现 f.死亡的神经元富含皮质输入。 g。死亡的神经元富含 AMPAR，其中一些似乎更多 缺乏 GluR2（GluR2 假说）。 根据这些观察，申请人得出结论：“HD 突变可能会导致 皮质纹状体神经元具有破坏性而不是使纹状体神经元 易受伤害的。” 这些假设将在 5 个具体目标中得到检验： 目标 1：使用单细胞 RT-PCR、免疫沉淀以及 LM 和 EM 免疫标记 表征 AMPA 受体的丰度和亚基组成 关于 HD 易损和 HD 抵抗纹状体中间神经元和投射神经元 大鼠中的类型。 目标 2：表征纹状体中间神经元和投射之间的差异 AMPAR 中的神经元介导对皮质输入和亚基的突触反应 依赖的 AMPA 生理学（钙渗透性、整流和脱敏） 在大鼠中 目标 3：药理学表征 AMPAR 的作用和 选择性死亡中 mGluR2/3 调节的皮质纹状体谷氨酸释放 长期给予 3NP 的大鼠纹状体神经元（HD 模型）。 目标 4：使用原位杂交组织化学、LM 和 EM 免疫来确定 在猴子的纹状体神经元和HD纹状体中是否分布 HD 易感纹状体神经元和 HD 抵抗纹状体神经元中的 AMPAR 亚基是一致的 及其在选择性神经变性中的假设作用。 目标 5：使用原位杂交组织化学、LM 和 EM 免疫来确定 在 HD 转基因大鼠模型和人类 HD 标本中，无论 HD 是否存在 突变降低皮质纹状体神经元及其纹状体内的 mGluR2/3 终端。