BETA AMYLOID-INDUCED RNA OXIDATION AS A MEDIATOR OF AD PATHOGENESIS

阿尔茨海默病（AD）是美国的主要健康问题之一， 如果不采取措施加以治疗或预防，老年痴呆症将变得更加突出。 AD中选择性神经元变性的发病机制是确定预防或治疗的关键 措施有一个快速增长的知识体系，表明自由基介导的氧化 损伤参与AD的发病机制。我们最近的研究表明， 遗忘型轻度认知障碍患者脑脂质、蛋白质、DMA和RNA的损害， AD的可检测阶段，表明氧化损伤是AD的早期事件，并非继发于 神经变性这一建议的主要假设是，早期AD中的RNA氧化是由细胞凋亡介导的。 部分由淀粉样β肽（AP）引起，AP促进蛋白质合成受损和神经元功能障碍。在 具体目标1和2，我们将定量RNA氧化和神经元中的修饰， AD从正常到MCI到晚期AD（LAD）的进展，以及在APP/PS1基因敲入转基因小鼠中， 使用免疫组织化学、共聚焦显微镜和抗8-OHG、丙烯醛/鸟嘌呤抗体 加合物和MC-1。在正常对照组、疾病对照组（额颞叶）的相同脑区中， 痴呆）、MCI和LAD以及APP/PS-1小鼠的脑标本，我们将定量 通过GC-MS-SIM纯化的rRNA、tRNA和mRNA池，并使用 在具体目标3中，我们将确定来自核心B的有毒和无毒Ap的能力，以确定 RNA氧化和丙烯醛/鸟嘌呤加合物在培养的神经元，并比较这与RNA氧化 在特定目的1和2中观察到的体内结果。在具体目标4中，我们将确定单个mRNA是否 在对照受试者和MCI、LAD和MCI受试者的脑中， 额颞叶痴呆患者然后，我们将确定预测的蛋白质编码的 氧化的mRNA在从正常到MCI到LAD的进展中表现出降低的表达和功能。 具体目标5将定义组蛋白去乙酰化酶抑制剂改善AP诱导的神经毒性的能力 在体外和在APP/PS1转基因小鼠中。我们有所有具体目标的初步数据表明， 这些研究的可行性。通过以无偏见的方式进行这些研究， 和大脑标本来指导我们，我们将定义Ap如何促进AD中的神经元功能障碍。本研究 鉴定用于开发旨在减少神经元损伤的治疗剂的分子靶点的潜力 损伤和减缓AD的进展或潜在地预防AD。

Alzheimer's disease (AD) is one of the major health problems in the United States and as our population ages it will become more prominent unless measures to treat or prevent it are found. Understanding the pathogenesis of selective neuron degeneration in AD is the key to defining preventive or therapeutic measures. There is a rapidly increasing body of knowledge that indicates free radical-mediated oxidative damage is involved in the pathogenesis of AD. Our recent studies have demonstrated significant oxidative damage to brain lipids, proteins, DMA, and RNA in amnestic mild cognitive impairment, the earliest detectable phase of AD, indicating that oxidative damage is an early event in AD and not secondary to neurodegeneration. The major hypothesis of this proposal is that RNA oxidation in early AD is mediated in part by amyloid-beta peptide (AP) that promotes impairment of protein synthesis and neuron dysfunction. In Specific Aims 1 and 2, we will quantify RNA oxidation and aldehydic modifications in neurons in the progression of AD from normal to MCI to late AD (LAD), and in the APP/PS1 knock-in transgenic mice over time using immunohistochemistry, confocal microscopy, and antibodies against 8-OHG, acrolein/guanine adducts, and MC-1. In the same brain regions of normal controls, disease controls (frontotemporal dementia), MCI and LAD, and brain specimens from APP/PS-1 mice, we will quantify RNA oxidation in purified pools of rRNA, tRNA, and mRNA by GC-MS-SIM and acrolein-modified guanine in these pools using LC-MS-MS. In Specific Aim 3, we will determine the ability of toxic and non-toxic Ap from Core B to define RNA oxidation and acrolein/guanine adducts in cultured neurons and compare this with the RNA oxidation observed in vivo in Specific Aims 1 and 2. In Specific Aim 4, we will determine if the individual mRNAs oxidized in response to Ap in vitro are also oxidized in the brains of control subjects and MCI, LAD, and frontotemporal dementia patients. We will then determine whether the predicted proteins encoded by the oxidized mRNAs exhibit decreased expression and function in the progression from normal to MCI to LAD. Specific Aim 5 will define the ability of histone deacetylase inhibitors to ameliorate Ap-induced neurotoxicity in vitro and in the APP/PS1 transgenic mice. We have preliminary data in all specific aims indicating the feasibility of these studies. By conducting these studies in an unbiased manner and allowing the neurons and brain specimens to guide us, we will define how Ap promotes neuron dysfunction in AD. This study has the potential of identifying molecular targets for development of therapeutic agents aimed at reducing neuron injury and slowing the progression of or potentially preventing AD.