Neuroinflammation in Cholesterol-Induced AD Pathogenesis

阿尔茨海默氏病（AD）是一种进行性神经退行性疾病，是阿尔茨海默氏病的最普遍形式。 老年痴呆症病理学的特征是淀粉样蛋白β（Ap）的积累， 淀粉样前体蛋白（amyloid precursor protein，APR）淀粉样蛋白级联假说提出，Ap寡聚体引起 通过小胶质细胞的激活及其神经毒性物质的产生直接和间接地损伤神经元。 分子。最近的发现（遗传、实验和流行病学）表明异常之间存在联系 胆固醇代谢和AD的发病机制。该项目测试的假设， 胆固醇稳态促进了与以下疾病相关的神经炎症反应的加剧： 增加的Ap生成，这反过来导致AD特征性的神经变性。研究将使用： 高脂肪/胆固醇饮食喂养高胆固醇血症、低密度脂蛋白受体敲除（LDLR-/-）小鼠， 表达野生型人APR（类似于散发性AD）的小鼠品系，以及表达野生型人APR（类似于散发性AD）的小鼠品系之间的杂交。 两个.该项目的具体目标如下： * 确定高胆固醇喂养的LDLR-/-、wtAPP和 免疫组化检测wtAPP/LDLR-/-小鼠脑内活化的小胶质细胞和脑血管细胞 与淀粉样蛋白水平和突触毒性的关系（即，突触素免疫反应性丧失）。炎性 介体（即，细胞因子、促氧化酶）、Ap肽和与胆固醇有关的蛋白质 稳态（即，ApoE，ABCA 1）将通过生物化学和免疫化学技术进行定量。 4确定与受损脑胆固醇相关的促炎和抗炎刺激的性质和作用， 使用细胞培养模型的酯代谢。神经胶质和神经胶质-神经元共培养物的培养物将用于 研究氧化脂蛋白和ApoE亚型（存在或不存在Ap）对胶质细胞的影响。 炎症反应（即，介质的产生）和对神经元APR加工的影响。此外，反- 核受体的氧固醇配体的炎症和抗淀粉样蛋白生成作用，即，肝X受体 (LXR)将进行审查并探讨机制。 * 测试合成LXR配体（T0901317）在降低胆固醇和降低胆固醇方面的治疗潜力 抗炎特性，和米诺环素，四环素衍生物已知抑制小胶质细胞活化， 通过检查神经病理学（即，AP肽水平和突触毒性）和行为变化（8- 臂水迷宫表现）平行于减弱高胆固醇血症小鼠中的神经炎症。 这些研究的结果应该对开发新的和有效的抗- 炎症治疗AD。

Alzheimer's disease (AD), a progressive neurodegenerative condition, is the most prevalent form of dementia in the elderly. The pathology is characterized by an accumulation of amyloid beta (Ap), the product of amyloid precursor protein (APR). The amyloid cascade hypothesis proposes that Ap oligomers cause neuronal injury both directly and indirectly via an activation of microglia and their production of neurotoxic molecules. Recent findings (genetic, experimental, and epidemiological) suggest a link between abnormal cholesterol metabolism and the pathogenesis of AD. The project tests the hypothesis that failure of cholesterol homeostasis facilitates an exacerbated neuroinflammatory response in association with increased Ap generation that, in turn, leads to neurodegeneration characteristic of AD. The studies willuse: high fat/cholesterol diet fed hypercholesterolemic, low density lipoprotein receptor knockout (LDLR-/-) mice, a mouse strain expressing the wild type human APR (akin to sporadic AD), as well as the cross between the two. The specific objectives of the project are as follows: * Determine neuroinflammatory changes in brain regions of high cholesterol-fed LDLR-/-, wtAPP and wtAPP/LDLR-/- mice by immunohistochemical detection of activated microglia and cerebrovascular cells in relation to amyloid levels and synaptotoxicity (i.e., loss of synaptophysin-immunoreactivity). Inflammatory mediators (i.e., cytokines, pro-oxidant enzymes), Ap peptides, and proteins involved in cholesterol homeostasis (i.e., ApoE, ABCA1) will be quantified by biochemical and immunochemical techniques. 4 Determine the nature and role of pro- and anti-inflammatory stimuli relevant to impaired brain chol- esterol metabolism using cell culture models. Cultures of glia and glial-neuronal co-cultures will be used to investigate the effects of oxidized lipoproteins and ApoE isoforms (in the presence or absence of Ap) on glial inflammatory response (i.e., production of mediators) and on neuronal APR processing. Also, the anti- inflammatory and anti-amyloidogenic effects of oxysterol ligands of a nuclear receptor, i.e., Liver X Receptor (LXR) will be examined and the mechanisms explored. *Test the therapeutic potential of a synthetic LXR ligand (T0901317) with both cholesterol lowering and anti-inflammatory properties, and minocycline, a tetracycline derivative known to suppress microglial activa- tion, by examining neuropathological (i.e., Ap peptide levels and synaptotoxicity) and behavioral changes (8- arm water maze performance) in parallel to attenuated neuroinflammation in hypercholesterolemic mice. The outcome of these studies should have implications for developing novel and effective anti- inflammatory treatments for AD.