Neuroinflammation in Cholesterol-Induced AD Pathogenesis

阿尔茨海默病(AD)是一种进行性神经退行性疾病，是最常见的 老年痴呆症。病理的特征是淀粉样β蛋白(AP)的积聚。 淀粉样前体蛋白(APR)。淀粉样蛋白级联假说认为，AP寡聚体导致 通过激活小胶质细胞及其产生神经毒性而直接或间接地造成神经元损伤 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。 胆固醇代谢与AD的发病机制。该项目测试了一种假设，即 胆固醇稳态促进加重的神经炎性反应 AP生成增加，进而导致AD的神经退行性变特征。这些研究将使用： 高脂/胆固醇饮食喂养高胆固醇血症低密度脂蛋白受体基因敲除(LDLR-/-)小鼠， 表达野生型人类APR的小鼠品系(类似于散发性AD)，以及 二。该项目的具体目标如下： *确定高胆固醇喂养的LDLR-/-、wtAPP和 WtAPP/LDLR-/-小鼠体内活化的小胶质细胞和脑血管细胞的免疫组织化学检测 与淀粉样蛋白水平和突触毒性(即，突触素免疫反应性丧失)的关系。炎症性 与胆固醇有关的介体(即细胞因子、促氧化酶)、AP多肽和蛋白质 动态平衡(即载脂蛋白E、ABCA1)将通过生化和免疫化学技术进行量化。 4确定与脑胆固醇受损相关的促炎和抗炎刺激的性质和作用- 利用细胞培养模型研究酯醇代谢。神经胶质细胞培养和神经胶质细胞-神经元共培养将用于 研究氧化型脂蛋白和载脂蛋白E亚型(在AP存在或不存在的情况下)对胶质细胞的影响 炎症反应(即，介质的产生)和神经元APR的处理。另外，反- 核受体即肝X受体的氧固醇配体的炎症和抗淀粉样变作用 (LXR)将被审查并探索其机制。 *测试合成LXR配体(T0901317)的治疗潜力，同时降低胆固醇和 抗炎特性，以及米诺环素，一种已知的抑制小胶质细胞活性的四环素衍生物- 通过检测神经病理(即AP肽水平和突触毒性)和行为变化(8- 手臂水迷宫表现)与减轻高胆固醇血症小鼠的神经炎症平行。 这些研究的结果将对开发新的和有效的抗病毒药物具有重要意义。 阿尔茨海默病的炎性治疗。

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.