PATHOGENESIS OF PHOSPHOLIPASES A2 IN AD

有强有力的支持这一假说，折叠的p-淀粉样蛋白(AP)成神经毒性，寡聚体 形态与氧化应激增加有关，氧化应激构成神经元损伤的早期事件 以及阿尔茨海默病(AD)中出现的神经胶质细胞介导的炎症。磷脂酶A2(PLA2)，包括 胞浆型cPLA2和炎症性分泌型sPLA2-IIA是合成脂质的重要酶 介体和维持膜的完整性。尽管这些酶被认为与 其他疾病，它们在AD发病机制中的作用还没有得到充分的研究。我们最近的研究 已经获得了新的数据，表明寡聚Ap42处理神经元可以增强ROS的产生 通过NADPH氧化酶，并通过激活细胞内激酶增加cPLA2活性，从而导致 膜过氧化和膜蛋白功能的改变。其他新数据显示，sPLA2-IIA 与年龄匹配的对照组相比，阿尔茨海默病患者脑组织中mRNA和蛋白的表达均升高。整体而言 本项目的目标是了解A|3、NADPH氧化酶、cPLA2和sPLA2-IIA 共同导致神经元功能受损和神经胶质细胞介导的诱导 炎症，使用公认的和新的AD体外和体内模型。Aim 1验证这一假说 AP诱导神经元cPLA2和NADPH氧化酶激活对N-甲基-D-天冬氨酸的调节作用 酸性(NMDA)受体的功能和诱导神经细胞凋亡。目标2调查研究的意义和 新的初步数据表明sPLA2-IIA在AD中上调与AD发病机制的相关性 并验证了寡聚体Ap42和NADPH导致sPLA2-IIA表达增加的假设 依赖于氧化酶的ROS的产生调节神经胶质细胞的炎症反应，并导致神经元 细胞凋亡。我们将检验NADPH氧化酶和cPLA2上调sPLA2-IIA表达的假设 并调节神经胶质细胞的炎症反应，从而将氧化途径与神经炎症联系起来。 评估PLA2在AD相关神经元和神经胶质细胞功能中的新作用的拟议研究 将评估AD，NT-2的TgCRNDS小鼠模型的原代神经元和星形胶质细胞的反应 过度表达瑞典/印第安纳突变体APP的细胞，人类AD和非痴呆(ND)脑组织， 和来自转基因小鼠模型的脑切片，包括TgCRNDS和TgCRNDS x sPLA2-IIA，以及小鼠 缺乏cPLA2和gp91Phox，这是一个NADPH氧化酶亚基。总之，这些研究将提供新的 神经元cPLA2在增强氧化应激和损伤谷氨酸能中的作用 AD早期阶段的信号转导，以及sPLA2-IIA在胶质细胞炎症反应中的作用， 我们相信可以导致新的药物疗法来延缓疾病进展的信息。

There is strong support for the hypothesis that folding of p-amyloid (AP) peptide into a neurotoxic, oligomeric form is associated with increased oxidative stress that constitutes early events in the neuronal impairment and glial cell-mediated inflammation seen in Alzheimer's disease (AD). Phospholipases A2 (PLA2), including cytosolic cPLA2 and inflammatory secretory sPLA2-IIA, are important enzymes for the production of lipid mediators and the maintenance of membrane integrity. Although these enzymes have been implicated in other diseases, their roles in the pathogenesis of AD have not been explored sufficiently. Our recent studies have obtained novel data indicating that oligomeric Ap42 treatment of neurons enhances ROS production through NADPH oxidase and increases cPLA2 activity through intracellular kinase activation, resulting in membrane peroxidation and alterations in membrane protein function. Other new data show that sPLA2-IIA mRNA and protein expression are elevated in AD brain compared to age-matched controls. The overall goal of this project is to understand mechanisms whereby A|3, NADPH oxidase, cPLA2 and sPLA2-IIA collectively contribute to impairment of neuronal function and induction of glial-cell mediated inflammation, using accepted and novel in vitro and in vivo models of AD.Aim 1tests the hypothesis that Ap-induced cPLA2 and NADPH oxidase activation in neurons serves to modulate N-methyl-D-aspartic acid (NMDA) receptor function and induce neuronal apoptosis. Aim 2 investigates the significance and relevance to AD pathogenesis of the novel preliminary data indicating that sPLA2-IIA is up-regulated in AD and tests the hypothesis that increases in sPLA2-IIA expression caused by oligomeric Ap42 and NADPH oxidase-dependent ROS generation modulate inflammatory responses in glial cells and cause neuronal apoptosis. We will test the hypothesis that NADPH oxidase and cPLA2 up-regulate sPLA2-IIA expression and modulate inflammatory responses in glial cells, thus linking oxidative pathways to neuroinflammation. Proposed studies to evaluate novel roles for PLA2s in neuronal and glial cell functions associated with AD will evaluate responses in primary neurons and astrocytesfrom the TgCRNDS mouse model of AD, NT-2 cells over-expressing the Swedish/Indiana mutant of APP, human AD and non-demented (ND) brain tissue, and brain slices from transgenic mouse models, including TgCRNDS and TgCRNDS x sPLA2-IIA, and mice lacking cPLA2 and gp91phox, a NADPH oxidase subunit. Together, these studies will provide new information about the roles of neuronal cPLA2 in enhancing oxidative stress and impairing glutamatergic signaling in the early stages of AD, and the role of sPLA2-IIA in inflammatory responses in glial cells, information that we believe can lead to novel pharmacotherapies to retard disease progression.