Nitration of Amyloid beta Alzheimer 's disease

阿尔茨海默病（AD）的特征在于老年斑中淀粉样蛋白β（Abeta）肽的细胞外沉积。与此沿着的是神经炎症，导致诱导型一氧化氮合酶2（NOS 2）及其高活性产物一氧化氮（NO）的产生增加，其能够引入翻译后修饰，这些NO介导的翻译后修饰之一是A β在酪氨酸10处的硝化（硝化A β）。这种物质定位于AD中淀粉样斑块的核心，并且能够启动斑块的形成。此外，在AD的小鼠模型（APP/PS1小鼠）中，N 0 S2的消融减少了Abeta沉积和认知功能障碍。为了理解AD中N 0 S2的诱导并测试早期参与硝化Abeta的形成是否是潜在的治疗方法，提出了三个目标：1.确定哪些细胞类型和脑区表达NOS 2，以及这种模式如何受到野生型和AD小鼠模型中衰老的影响。揭示APP/PS1小鼠脑内NOS 2表达与斑块发生的时空相关性。我们将确定是否含有核心的淀粉样蛋白斑块特异性地在NOS 2表达的位点发展3。测试针对硝化Abeta的免疫是否改善APP/PS1小鼠中的斑块病理学和行为缺陷。我们将进行被动和主动免疫，以改善APP/PS1小鼠的记忆和学习表型，并减少斑块。在第一和第二个目标中，将使用表达tdTomato和NOS 2启动子下的CRE重组酶的转基因小鼠与CRE-EYFP报告小鼠杂交，评估NOS 2的表达。使用这种小鼠，有可能监测NOS 2的瞬时表达以及偶发性表达。采用体内显微镜方法，我们将澄清淀粉样蛋白斑块是否出现在先前和/或正在进行的NOS 2表达的位点。对于被动免疫研究，我们实验室最近开发的针对硝化Abeta（4A 4 E8）的新抗体将与N-末端Abeta抗体进行比较。将进行主动免疫研究，比较包含硝化的Abeta表位的肽与非硝化的肽的效果。治疗的有效性将通过测试记忆和学习以及斑块病理学的变化来监测。在这个项目中，一个新的和创新的治疗策略将通过描述AD中NOS 2的早期表达和通过使用仅在病理条件下发生的Abeta的后修饰表位进行预防性免疫来研究。因此，这种方法避免了针对肽的预防性免疫中自身免疫的潜在问题，该肽的功能至今仍是未知的。

Alzheimer's disease (AD) is characterized by the extracellular deposition of the amyloid beta (Abeta) peptide in senile plaques. Coming along with that is an neuroinflammation resulting in the increased production of the inducible form of the nitric oxide synthase 2 (NOS2) and its highly reactive product nitric oxide (NO), which is able to introduce post-translational modifications.One of these NO-mediated post-translational modification is the nitration of Abeta at tyrosine 10 (nitrated Abeta). This species is localized to the core of amyloid plaques in AD and is able to initiate the formation of plaques. Furthermore, ablation of NOS2 decreased Abeta deposition and cognitive dysfunction in an mouse model of AD (APP/PS1 mice).To understand the induction of NOS2 in AD and to test if early engagement with the formation of nitrated Abeta is a potential therapeutic approach, three objectives are proposed:1. To determine which cell types and brain areas express NOS2 and how this pattern is influenced by aging in wild type and in an AD mouse model.2. To reveal the spatial and temporal correlation of NOS2 expression in cells of the brain and the occurrence of plaques in APP/PS1 mice. We will determine whether core-containing amyloid plaques specifically develop at sites of NOS2 expression 3. To test if immunization against nitrated Abeta ameliorates the plaque pathology and the behavioral deficits in APP/PS1 mice. We will conduct passive and active immunization to improve the memory and learning phenotype and to reduce plaque in APP/PS1 mice.In the first and second objective, expression of NOS2 will be evaluated using a transgenic mouse that express a tdTomato and the CRE recombinase under the NOS2 promoter crossbred with a CRE-EYFP reporter mouse. Using this mouse it is possible to monitor transient as well as episodic expression of NOS2. Employing an in vivo-microscopy approach we will clarify if amyloid plaques appear at sites of previous and/or ongoing NOS2 expression. For passive immunization studies a new antibody against nitrated Abeta (4A4E8), recently developed in our laboratory, will be compared to an N-terminal Abeta antibody. Active immunization studies will be performed comparing the effect of a peptide comprising the nitrated Abeta epitope to the non-nitrated peptide. The effectiveness of the treatments will be monitored by testing memory and learning as well as changes in the plaque pathology.In this project a new and innovative therapeutic strategy for AD will be investigated by characterizing the early expression of NOS2 in AD and by conducting preventive immunizations using a post-translationally modified epitope of Abeta that only occurs under pathological conditions. This approach thus avoids the potential problem of autoimmunity in preventive immunizations against a peptide which function to this day is still unknown.