环氧合酶-2代谢紊乱促进β-淀粉样蛋白在阿尔茨海默病中产生、传播和沉积的神经病理学机制研究

Alzheimer’s disease (AD) is (patho) physiologically characterized by the formation of amyloid plaques (AP) and tau hyperphosphorylation. Prior works have demonstrated that cyclooxygenase-2 (COX-2) metabolic disturbance accelerated the production of Aβ and Aβ deposition in AD patients. However, the mechanisms of Aβ production, propagation and deposition remain unclear. Using COX-2-specific inhibitor and sophisticated biotechnologies, including super-resolution, two-photon live cell and live animal imaging, signal transduction, molecular cell biology and morphology, we will elucidate the molecular mechanisms and signaling pathways that COX-2 regulates Aβ production, propagation and deposition in multiple experimental models. . Specifically for in vitro study, we will explore the molecular mechanisms or signaling pathways that COX-2 and its metabolic products (Prostaglandins, PGs) reuglate the production of proinflammatory cytokines in glial cells, which in turn modulates the expression of α-, β-, γ-secretases in neuron cells. Crosstalk between glial and neuron cells will finally result in the production of Aβ. To further consolidate these data, the cleavage products of amyloid precursor protein (APP) including sAPP, sAPPβ, C95 and C83 will be monitored. By transfecting HEK293 and SH-SY5Y cells with GFP- or mCherry-Aβ plasmids, we will next to study the mechanisms of Aβ propogation between neuronal cells. Taking the advantage of bimolecular fluorescence complementation (BiFC) system, we will finally elucidate the mechanisms of misfolded Aβ deposition in recipient cells. . In light of these above observations in vitro, the production, propagation and deposition of Aβ should be further validated in vivo. In detail, 3-months old COX-2, APP/PS1 or COX-2/APP/PS1 transgenic mice were administered with COX-2 specific inhibitor for 6 months. The expression of inflammatory cytokines and α-, β- or γ-secretases as well as the production of Aβ will be determined in COX-2 inhibitor-treated transgenic mice. The key molecules invovled in Aβ production will be reinforced in mice. Like in vitro experiments, injection of fluorescence labled Aβ to the cerebral cortex, hippocampus or cerebral ventricles will be used to determine the ability of Aβ to transmit between cells, cross synapses and transport along neural processes, axon and dendrites. In vivo, we will finally fulfill the mechanisms that misfolded Aβ acts as a seed to faciliate the deposition of Aβ and formation of amyloid plaque (AP) by injecting oligomeric Aβ into the brain of AD mice, which lead to cognitvie decline of Tg mice. In light of establishing the models of AD investigation in vitro and in vivo, we will summarize and reconstruct the signaling network that regulates COX-2-mediated AD progression, which are instrumental for understanding molecular mechanisms of AD. More importantly, these observations will help us screening, developing and improving COX-2 inhibitor drug delivery system.

阿尔茨海默病（AD）的主要病理特征之一是脑内出现β-淀粉样蛋白（Aβ）沉积。申请者的创新性研究结果表明，环氧合酶-2（COX-2）代谢紊乱具有促进Aβ产生及Aβ在AD患者脑内沉积的功能。然而，COX-2介导的Aβ产生、传播及沉积等一系列科学问题尚未解决。鉴于此，本项目拟采用COX-2特异性抑制剂、超高分辨成像、双光子激光扫描技术、小鼠成像系统和活细胞工作站，结合信号传导、分子生物学和行为学等手段，明确COX-2及其代谢产物（PGs）调控淀粉样前体蛋白（APP）异常剪切、Aβ在神经元细胞间“类朊蛋白样”传播及Aβ在淀粉样斑块形成过程中“种子效应”的确切分子机制。在此基础上，筛选对COX-2介导的Aβ产生、传播和沉积具有抑制作用的小分子化合物，从而建立有效的AD干预措施，最终为防治AD奠定理论和实践基础。

阿尔茨海默病（AD）的主要病理特征之一是脑内出现β-淀粉样蛋白（Aβ）沉积。申请者的创新性研究结果表明，环氧合酶-2（COX-2）代谢紊乱具有促进Aβ产生及Aβ在AD患者脑内沉积的功能。然而，COX-2介导的Aβ产生及沉积等一系列科学问题尚未解决。鉴于此，本项目拟采用COX-2特异性抑制剂, 结合信号传导、分子生物学和行为学等手段，明确COX-2及其代谢产物（PGs）调控淀粉样前体蛋白（APP）异常剪切、Aβ在神经元细胞间传播及Aβ在淀粉样斑块形成过程中的确切分子机制。在此基础上，筛选对COX-2介导的Aβ产生、传播和沉积具有抑制作用的小分子化合物，从而建立有效的AD干预措施，最终为防治AD奠定理论和实践基础。