蛋白磷酸酯酶-2A对星形胶质细胞迁移的促进作用及其机制研究

发布时间：2018-05-27 05:38

本文选题：阿尔兹海默病 + 蛋白磷酸酯酶2A　；参考：《华中科技大学》2012年博士论文

【摘要】：背景：阿尔茨海默病(Alzheimer disease, AD)是一种以进行性认知障碍和记忆功能损害为主的中枢神经系统退行性疾病。主要病理特征是神经细胞外老年斑(senile plaques, SP)沉积和神经元内神经原纤维缠结(neurofibrillary tangles, NFT)。Alois Alzheimer首先在痴呆病人大脑脑片中发现：老年斑周围围绕着大帚的反应性星形胶质细胞。无论在大脑神经元发育还是神经退行性变时均存在星形胶质细胞的迁移。反应性星形胶质细胞是如何迁移到老年斑块周围的?目前已有大量研究表明蛋白磷酸激酶参与了星形胶质细胞的迁移,而蛋白磷酸酯酶对星形胶质细胞的迁移作用方面的研究报道则较少见。目的：研究蛋白磷酸酯酶-2A(protein phosphatase-2A, PP2A)对星形胶质细胞迁移的影响并阐述其机制。方法：本实验采用免疫共沉淀(Immunoprecipitation)、免疫印迹(Western blotting)、免疫荧光技术和PP2A活性试剂盒检测AD样Tg2576转基因鼠脑中星形胶质细胞中PP2A的活性。以体外培养的原代星形胶质细胞为研究模型,采用PP2A特异性抑制剂(OA)或激动剂(DES),并结合脂质体和Amax核电转技术导入外源性DNA,从不同角度分别调节PP2A活性,采用细胞划痕和Transwell实验研究PP2A对细胞迁移的作用。结果：Tg2576转基因鼠中星形胶质细胞内PP2A活性增强。在原代培养星形胶质细胞划痕实验中,给予PP2A抑制剂OA,及siPP2A抑制PP2A活性后,可抑制星形胶质细胞的迁移,而给予PP2A激活剂DES及转染wtPP2A激活PP2A后,则可促进星形胶质细胞的迁移。Transwell小室实验结果与划痕实验结果一致。过表达wtPP2A促进星形胶质细胞迁移的同时,无论细胞胞体还是发生迁移的伪足,其纤维状肌动蛋白(F-actin)的表达显著增高且呈聚集状态。给予PP2A激动剂DES处理原代星形胶质细胞,结果发现激动PP2A可下调磷酸化丝裂原活化蛋白激酶p38MAPK (p38MAPK)水平,而磷酸化c-Jun氨基末端激酶(pJNK)及磷酸化细胞外调节蛋白激酶(pERK)水平无明显变化,而上调p38MAPK可部分逆转PP2A所诱导的星形胶质细胞的迁移作用。结论：PP2A可通过增加F-actin的聚集和降低p38MAPK活性而促进星形胶质细胞的迁移。Tg2576转基因鼠中星形胶质细胞PP2A活性增强促进星形胶质细胞迁移到老年斑块周围,发挥其清除Aβ作用。这不仅为星形胶质细胞的迁移提供了新的理论机制,同时为通过调节星形胶质细胞迁移改善胶质病理提供的新的理论基础。
[Abstract]:BACKGROUND : Alzheimer disease ( AD ) is a degenerative disease of the central nervous system based on progressive cognitive impairment and memory impairment . Alois Alzheimer ' s disease ( Alzheimer ' s disease ) was first found in the brain slices of dementia patients : the presence of reactive astrocytes around the senile plaques around the senile plaques .
Objective : To study the effect of protein phosphatase - 2A ( PP2A ) on the migration of astrocytes and expound its mechanism .
Methods : The activity of PP2A in the brain of AD - like Tg2576 transgenic mice was detected by Immunoptophore , Western blotting , immunofluorescence and PP2A . In vitro , PP2A - specific inhibitor ( OA ) or agonist ( DES ) was used to study the effect of PP2A on the migration of PP2A from different angles .
Results : The activity of PP2A was enhanced in the astrocytes of Tg2576 transgenic mice . After PP2A inhibitor OA was administered and PP2A was inhibited by siPP2A , the migration of astrocytes was inhibited .
Conclusion : PP2A can promote the migration of astrocytes by increasing the aggregation of F - actin and decreasing the activity of p38MAPK .
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R749.16

【引证文献】