ALTERATIONS OF MICROGLIAL PHENOTYPE AND FUNCTION IN AGING AND ALZHEIMER'S DISEASE

阿尔茨海默病（AD）与淀粉样蛋白斑块附近的小胶质细胞的活化相关，其具有由于神经毒性和促炎介质的释放而导致的有害结果和由于淀粉样蛋白吞噬作用而导致的有益效果。越来越多的人认识到，与正常衰老相比，AD与免疫系统的先天性和适应性臂的损伤有关。作为关键的先天免疫细胞，小胶质细胞衰老可能有助于神经退行性疾病的发生或进展。外周巨噬细胞和小胶质细胞可以采用不同的刺激依赖性激活状态，称为经典激活和替代激活，具有不同的相关功能。关于这些不同的小胶质细胞激活状态对AD发病机制和疾病过程的贡献知之甚少。这项建议将测试的假设，即小胶质细胞的激活模式和表型是不同的影响，在健康和病理老化，并有助于受损的淀粉样蛋白吞噬在AD。我们将首先建立一个微阵列基因签名的经典和替代激活状态暴露培养死后人类小胶质细胞适当的细胞因子刺激。使用流式细胞术、实时PCR和 通过免疫组织化学技术，我们将比较来自无AD病理的老年患者、轻度AD病理但无痴呆的老年患者和来自痴呆AD患者的小胶质细胞的活化模式和潜力。我们预计经典激活电位没有差异，但替代激活的年龄和疾病依赖性下降。最后，我们将评估这些患者组之间的激活状态依赖的功能差异进行淀粉样蛋白吞噬试验，并测量释放的趋化因子，细胞因子和神经营养因子。总之，这些研究将有助于我们理解不同的小胶质细胞的功能和激活模式，将开始阐明在何种程度上，从老年和患病的大脑小胶质细胞是服从细胞因子刺激在体外，并将指出在体内调节小胶质细胞表型的潜在治疗手段。

Alzheimer's disease (AD) is associated with activation of microglia in the vicinity of amyloid plaques with both detrimental results due to release of neurotoxic and pro-inflammatory mediators and beneficial effects due to amyloid phagocytosis. It is increasingly recognized that compared to normal aging, AD is associated with impairment of both innate and adaptive arms of the immune system. As key innate immune cells, microglial senescence may contribute to the development or progression of neurodegenerative diseases. Peripheral macrophages and microglia can adopt different stimulus-dependent activation states, termed classical and alternative activation, with different associated functions. Little is known about the contribution of these different microglial activation states to AD pathogenesis and disease course. This proposal will test the hypothesis that microglial activation patterns and phenotypes are differentially affected in healthy and pathological aging and contribute to impaired amyloid phagocytosis In AD. We will first establish a microarray gene signature for classical and alternative activation states by exposing cultured postmortem human microglial cells to appropriate cytokine stimuli. Using flow cytometry, real-time PCR and immunohistochemical techniques, we will then compare the activation pattern and potential of microglia derived from aged patients with no AD pathology, mild AD pathology but no dementia and from demented AD patients. We expect to see no differences in classical activation potential but an age- and disease-dependent decline in alternative activation. Lastly, we will evaluate activation-state dependent functional differences between these patient groups by performing amyloid phagocytosis assays, and measuring the release of chemokines, cytokines and neurotrophic factors. Together these studies will contribute to our understanding of distinct microglial functions and activation patterns, will begin to elucidate the degree to which microglia from aged and diseased brain are amenable to cytokine stimulation in vitro and will point to potential therapeutic means of modulating microglial phenotype in vivo.