塞来昔布脂质体鼻凝胶抑制tau蛋白磷酸化及其“类朊蛋白样”传播的分子机制研究

项目名称： 塞来昔布脂质体鼻凝胶抑制tau蛋白磷酸化及其“类朊蛋白样”传播的分子机制研究

项目编号： No.81500934

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 医药、卫生

项目作者： 关佩沛

作者单位： 东北大学

项目金额： 17.5万元

中文摘要： 流行病学调查发现长期服用环氧合酶-2（COX-2）特异性抑制剂塞来昔布（CB）的病人AD的发病率明显降低，并且COX-2代谢紊乱具有上调tau蛋白磷酸化的作用，然而CB作为一种难溶性药物如何透过血脑屏障及如何通过稳定COX-2代谢抑制tau介导的阿尔茨海默病（AD）发病机制尚不清楚。为此，本项目拟借助COX-2特异性抑制剂，采用脂质体鼻凝胶技术制备脑靶向CB药物传递系统，通过鼻饲处理Tau和Tau/COX-2转基因小鼠，借助CB共培养的新鲜脑片和原代培养细胞，结合药剂学、药理学、分子生物学和行为学等手段，阐明CB通过抑制COX-2活性降低脑内tau蛋白磷酸化、“类朊蛋白样”传播和NFTs形成过程中“种子效应”的分子机制，明确CB通过抑制COX-2活性降低tau蛋白活性来改善小鼠学习记忆能力的可能机制，揭示CB通过COX-2调控AD的作用机理，最终为防治AD提供科学依据。

中文关键词： 塞来昔布；阿尔茨海默病；脂质体鼻凝胶；tau蛋白磷酸化；蛋白质传播

英文摘要： Alzheimer’s disease (AD) is (patho)physiologically characterized by the formation of amyloid plaques (AP) and tau hyperphosphorylation. Epidemiological evidence has demonstrated that long-term treatment of osteoarthritis (OA) patients with nonsteroidal anti-inflammatory drugs (NSAIDs), such as Celecoxib (CB) markedly reduces the risk of AD. Most CB act upon local inflammatory events by inhibiting the expression of cyclooxygenase-2 (COX-2). Although COX-2 and its metabolic product, prostaglandins (PGs) are elevated in the brain of AD patients, the mechanisms remain unknown. As an insoluble drugs, liposomes incorporated nasal gel was employed to increase the distribution of CB in the brain. Using glial and neuron cells derived from either human or mouse as an in vitro model system, we demonstrate that COX-2 played pivotal roles in the pathogenesis of AD, which was reversed by the incubation of CB. Indeed, COX-2 mediated the reciprocal regulation of proinflammatory cytokines and tau phosphorylation between glial and neuron cells. In addition, we will elucidate the mechanisms or signaling pathways that COX-2 regulates the production of proinflammatory cytokines in glial cells, which in turn modulates the phosphorylation of tau in neuron cells. On the basis of these observations, we will next explore the mechanisms of tau propagation between cells by transfecting cells with GFP- or mCherry-tau plasmids. Once phosphorylated tau obtained the ability of transmission between cells, it is possibly able to accelerate the formation of neurofibrillary tangles (NFTs). To this end, bimolecular fluorescence complementation (BiFC) system will be used to determine the aggregation of phosphorylated tau in cultured cell level.. In light of the above observations in vitro, the biological functions of CB containing liposomes will be further administered via nasal feeding in the AD model of C57BL/6J mice. Specifically, 1-month old COX-2, tau or COX-2/tau transgenic mice were adminitrated with CB liposomes incorporated nasal gel for 8 months. The activities of signaling molecules and the phosphorylation of tau will be determined in CB liposomes-treated transgenic mice. As compared with non- or CB suspension-treated mice, the pivotal roles of COX-2 and its metabolic products, PGs in tau phosphorylation will be addressed. In addition, BiFC will be used to determine the cell transmission and synapse cross by cerebral cortex, hippocampus or cerebral ventricles injection in transgenic mice. Finally, the pivotal roles of phosphorylated tau in NFTs formation will be eluciated by tau injection to mesentery of mice. The proposed project will provide completely novel insights into the mechanisms of taupathies and fullfill the gaps between COX-2 metabolic disturbance and cognitive decline in AD. More importantly, these observations will help us developing and improving CB drug delivery system, such as lipososmes incorporated nasal gel to combat AD.

英文关键词： Celecoxib;Alzheimer’s disease;liposomes incorporated nasal gel;tau phosphorylation;protein propagation