Effects of intracranial rAAV.Neu3 on dementia and neuropathology

对记忆的有效评估可能是创作一部小说的最重要的组成部分 阿尔茨海默氏症的治疗。然而，记忆只是行为障碍中的一种 阿尔茨海默氏症患者表现出。他们也有情感和感觉运动缺陷，以及社交问题 行为。5xFAD转基因小鼠携带五种已知导致家族性阿尔茨海默病的突变 (时尚)。像其他阿尔茨海默病模型一样，他们在空间学习和空间学习测试中表现出严重的认知缺陷 记忆。与其他过度表达APP的小鼠不同，5xFAD转基因小鼠通过以下方式表现出强大的神经变性 9个月大。然而，5xFAD小鼠也表现出许多其他行为异常。例如, 它们对笼友表现出不正常的社交行为，不会表现出理发现象 具有相同品系的野生型小鼠的特征。尽管一份公布的报告显示，5xFAD小鼠花费在 更多的时间在一个正迷宫中张开双臂，这表明焦虑减少了，我们已经证明了这是 可归因于第IV层胡须桶中抑制性中间神经元的习惯性受损和退化 (想当然地是让人厌恶闭合的双臂)。在5xFAD转基因患者中，所有焦虑指数在我们的 举起手来。在这里提出的研究中，我们将确定神经节苷脂特异的小鼠唾液酸酶 Neu3可以增强认知，规范社会行为，防止神经元丢失和淀粉样蛋白相关 5xFAD小鼠的神经病理学。我们以前已经证明，脑室内注入唾液酸酶来自 霍乱弧菌(VCS)对红藻氨酸诱导的海马区损伤具有保护作用。VCs水解节苷脂和 产生一种类似于GD3合成酶(GD3S)抑制的脑神经节苷脂 在过度表达APP的转基因患者中，显示出神经保护、减少斑块和改善记忆。我们的 初步数据显示，输注VCS 8周对12个月大的婴儿具有神经保护作用，并减少斑块 5xFAD小鼠，但几个月来慢性输液的并发症，以及需要多次手术 更换泵使这种方法不切实际。相反，我们开发了一种重组腺相关基因 无限期产生神经氨酸酶3(Neu3)的病毒载体(RAAV)。在目前的研究中，小鼠将被 4个月龄时在背侧海马区注射rAAV.Neu3或rAAV.eGFP对照，当Aβ 表达和记忆损伤在5xFAD转基因中已经很明显。社交行为，社交 将在7至9个月期间对认知和空间记忆进行评估，并对焦虑和 感觉运动功能。尸检分析将评估阿尔茨海默氏症相关的神经病理和 神经退行性变。成功减少淀粉样蛋白负荷、细胞死亡和记忆损伤 转基因小鼠可能为阿尔茨海默病的新治疗策略提供洞察--治疗 可以减少或预防阿尔茨海默病患者的痴呆症和相关的行为症状。

A valid assessment of memory is perhaps the most important component of an endeavor to develop a novel treatment for Alzheimer's disease. However, memory is only one of the behavioral impairments that Alzheimer's patients exhibit. They also have affective and sensorimotor deficits, and problems with social behavior. The 5xFAD transgenic mouse bears five mutations known to cause familial Alzheimer's disease (FAD). Like other Alzheimer models, they exhibit profound cognitive deficits on tests of spatial learning and memory. Unlike other APP-overexpressing mice, the 5xFAD transgenics exhibit robust neurodegeneration by 9 months of age. However, the 5xFAD mice also show a host of other behavioral anomalies. For example, they exhibit abnormal social behavior toward their cage-mates and do not exhibit the barbering phenomenon characteristic of wild-type mice of the same strain. Although a published report shows that 5xFAD mice spend more time on open arms of a plus maze, indicative of decreased anxiety, we have shown that this is attributable to impaired habituation and degeneration of inhibitory interneurons in layer IV whisker barrels (putatively making closed arms aversive). All indices of anxiety in the 5xFAD transgenics were normal in our hands. In the studies proposed herein we will determine whether the ganglioside-specific murine sialidase Neu3 can enhance cognition, normalize social behavior, and prevent neuronal loss and amyloid-related neuropathology in the 5xFAD mice. We have shown previously that intraventricular infusion of sialidase from V. cholerae (VCS) protects against kainate-induced hippocampal damage. VCS hydrolyzes gangliosides and produces a brain ganglioside profile that is similar to that of GD3 synthase (GD3S) inhibition, which we have shown to be neuroprotective, reduce plaque, and improve memory in APP-overexpressing transgenics. Our preliminary data show that infusion of VCS for 8 weeks is neuroprotective and reduces plaque in 12-month-old 5xFAD mice, but complications with chronic infusion over months and the need for multiple surgeries to exchange pumps make this approach impractical. Instead, we developed a recombinant adeno-associated viral vector (rAAV) that produces neuraminidase 3 (Neu3) indefinitely. In the present study mice will be injected with rAAV.Neu3 or rAAV.eGFP control in the dorsal hippocampus at 4 months of age, when Aβ expression and memory impairments are already evident in 5xFAD transgenics. Social behavior, social cognition, and spatial memory will be assessed from 7 to 9 months, as well as control tests for anxiety and sensorimotor function. Post-mortem analyses will assess Alzheimer-related neuropathology and neurodegeneration. Successfully reducing amyloid burden, cell death, and memory impairments in the transgenic mice may provide insight into new treatment strategies for Alzheimer's disease--treatments that could reduce or prevent dementia and associated behavioral symptoms in Alzheimer patients.