PROJECT 2

反应性小胶质细胞已被认为在衰老相关的神经退行性过程中发挥作用， 包括阿尔茨海默病（AD）、帕金森病（PD）和肌萎缩侧索硬化（ALS）， 先前的研究表明，CD 45，一种膜结合蛋白酪氨酸， 与对照相比，AD脑中的小胶质细胞中的磷酸酶（PTP）升高。我们之前发现， 通过抗CD 45抗体刺激CD 45 PTP信号传导极大地抑制了 LPS或Abeta肽，如通过减少TNF-α产生、一氧化氮（NO）释放和神经元分泌所证明的。 损伤此外，这些作用依赖于抑制p44/42丝裂原活化蛋白激酶， 重要的促炎途径。因此，来自CD 45缺陷小鼠的原代培养的小胶质细胞 表现出对LPS和Abeta治疗的高反应性，如增加的TNF-α释放所证明的， NO生成和神经元损伤。作为这些发现在体内的验证，来自转基因小鼠的大脑 缺乏CD 45的淀粉样蛋白沉积模型显示TNF-α的产生显著增加， tau磷酸化（神经元损伤的早期标志物）与具有完整CD 45的转基因小鼠相比。 总之，这些结果表明，CD 45是小胶质细胞活化的负调节因子，并且具有治疗作用。 刺激CD 45 PTP信号通路的药物可有效抑制小胶质细胞活化 与衰老相关的疾病，如AD、PD和ALS。虽然CD 45表达随着 由于其具有炎症活性，因此预测其作用是防止失控的炎症反应。 在这个提议中，我们假设CD 45缺陷小鼠会在早期增加激活的小胶质细胞， 因此会表现出更强的神经退化为了验证这一假设，我们计划全面描述 CD 45信号通路在小胶质细胞活化调控中作用 以及由此产生的对小胶质细胞吞噬能力、细胞因子谱和 胆碱能/多巴胺能神经元，特别是其对阿尔茨海默氏症转基因小鼠衰老的影响， 对AD样病理学和行为变化的影响。这项工作将按照以下目标进行。（一） CD 45 PTP信号在小胶质细胞活化中的作用(2)CD 45在预防神经变性中的作用 我们计划比较不同年龄的CD 45缺乏和充足小鼠的炎症标志物， 小胶质细胞激活。具体而言，这些炎症和小胶质细胞活化的标志物将被关联 这些小鼠在认知功能和运动表现任务上的行为表现。(3)CD45 缺乏将加速阿尔茨海默病小鼠中的AD样病理和行为损伤。（四） 向CD 45缺陷小鼠施用蓝莓（BB）将导致减少的小胶质细胞炎症， 增加神经元细胞的成熟和改善认知/运动表现。

Reactive microglia have been suggested to play a role in aging-related neurodegenerative processes, including the Alzheimer's disease (AD), Parkinson's disease (PD) and Amyotrophic lateral sclerosis (ALS), and previous studies have shown that expression of CD45, a membrane-bound protein tyrosine phosphatase (PTP), is elevated in microglia in AD brain compared to controls. We previously found that stimulation of CD45 PTP signaling by anti-CD45 antibody greatly inhibits microglial activation induced by LPS or Abeta peptides, as evidenced by decreased TNF-alpha production, nitric oxide (NO) release, and neuronal injury. Further, these effects are dependent on inhibition of p44/42 mitogen activated protein kinase, an important pro-inflammatory pathway. Accordingly, primary cultured microglial cells from CD45-deficient mice demonstrate hyper-responsiveness to LPS and Abeta treatments, as evidenced by increased TNF-alpha release, NO production, and neuronal injury. As a validation of these findings in vivo, brains from a transgenic mouse model of amyloid deposition deficient for CD45 demonstrate markedly increased production of TNF-alpha and tau phosphorylation (an early marker for neuronal injury) compared to transgenic mice with intact CD45. Altogether, these results suggest that CD45 is a negative regulator of microglial activation, and therapeutic agents that stimulate the CD45 PTP signaling pathway may be effective in suppressing microglial activation associated with aging related disorders, such as AD, PD and ALS. Although CD45 expression increases with inflammatory activity, its role is predicted to prevent runaway inflammatory reactions. In this proposal, we hypothesize that CD45 deficient mice will increase activated microglia at an early age, and therefore will show increased neurodegeneration. To test this hypothesis, we plan to fully characterize the role of CD45 in modulation of microglial activation in vitro and in vivo by examining its signaling pathways and resultant effects on microglial phagocytic capability, cytokine profiles and degeneration of cholinergic/dopaminergic neurons, and specifically its impact on aging in Alzheimer transgenic mice, as its effects on AD-like pathology and behavioral changes. This work will be carried out by the following aims. (1) Function of CD45 PTP signaling on microglial activation. (2) Role of CD45 in preventing neurodegeneration. We plan to compare CD45 deficient and sufficient mice at different ages for markers of inflammation and microglial activation. Specifically, these markers of inflammation and microglial activation will be correlated with the behavioral performance of these mice on cognitive function and motor performance tasks. (3) CD45 deficiency will accelerate AD-like pathology and behavioral impairment in an Alzheimer mouse. (4) Administration of blueberry (BB) to CD45 deficient mice will result in reduced microglia-inflammation, increased maturation of neuronal cells and improved cognitive/motor performance.