不同聚集形式β-淀粉样肽对人SH-SY5Y细胞发动蛋白Ⅰ和突触素表达的影响

Effects of different assembly forms of β-amyloid peptide on dynamin Ⅰ and synaptophysin in human neuroblastoma SH-SY5Y cells

目的探讨不同聚集形式的β-淀粉样肽(Aβ)对人神经母细胞瘤细胞(SH-SY5Y细胞)发动蛋白Ⅰ(DynⅠ)和突触素(Syn)表达的影响。方法制备不同聚集形式的Aβ1～42处理SH-SY5Y细胞,采用蛋白质印迹法检测细胞中DynⅠ及Syn蛋白表达水平;采用免疫组织化学染色方法检测10例阿尔茨海默病(AD)患者及8例老年同龄对照者尸解后脑海马结构中β-淀粉样肽寡聚体(AβOs)表达水平。结果 Aβ单体或Aβ纤丝体处理SH-SY5Y细胞未见DynⅠ及Syn蛋白表达水平显著变化,AβOs处理细胞可见DynⅠ及Syn蛋白表达水平降低(P<0.05);AD患者海马及内嗅区皮质神经元内AβOs的表达显著高于老龄对照者(P<0.05)。结论细胞内表达的AβOs可能是引起AD患者脑中网格蛋白内吞调节蛋白———DynⅠ表达下降及突触丧失的主要Aβ神经毒性形式,该改变可能与AD发病机制中学习记忆能力减退有关。

Objective To investigate the effects of different assembly forms of β-amyloid peptide（Aβ1~42） on dynaminⅠ（DynⅠ） and synaptophysin（Syn） in human neuroblastoma SH-SY5Y cells.Methods The DynⅠ and Syn protein levels were measured by western blotting in human SH-SY5Y neuroblastoma cells treated with different assembly forms of Aβ1~42.β-amyloid oligomers（AβOs） in the hippocampal formation of ten cases of postmortem brains with Alzheimer Disease（AD） and eight cases without any neuronal disorders as age-matched controls were detected by immunohistochemical method.Results The DynⅠ and Syn protein levels were significantly declined in SH-SY5Y cells treated with AβOs（P0.05）,but not Aβ monomer and fibril.The AβOs-like immunoreactivity was significantly increased in the pyramidal cell of hippocampus and neuronal cells of the entorhinal cortex in AD patients as compared to controls（P0.05）.Conclusion Intracellular AβOs may be the main toxic form of Aβ,which reduced clathrin endocytosis regulated protein DynⅠ and synaptic loss,and might be a mechanism in connection with cognitive dificit of AD.