β淀粉样蛋白1～42诱导原代皮质神经元损伤过程中的淀粉样前体蛋白信号通路

背景:近年有研究表明纤维状β淀粉样蛋白能够促进细胞表面淀粉样前体蛋白在细胞外的积聚,导致神经损伤。目的:分析淀粉样前体蛋白信号通路在纤维状β淀粉样蛋白1～42诱导神经元损伤机制中的作用。方法:体外分离培养孕17.0～18.0d SD大鼠皮质神经元,培养7d后加入0(正常对照),0.05,0.5,5mol/L纤维状β淀粉样蛋白1～42,孵育8h建立毒性损伤模型,采用生化方法检测神经元细胞培养上清中的Calcein释放,分别用免疫荧光双标、Western blotting方法检测淀粉样前体蛋白和Fe65的表达。结果与结论:与正常对照组比较,加入不同浓度纤维状β淀粉样蛋白1～42诱导损伤8h后,神经元培养上清中Calcein释放增加(P<0.05或P<0.01),Western blotting和免疫荧光方法分别检测到淀粉样前体蛋白和Fe65的表达及共定位增加。说明纤维状β淀粉样蛋白1～42可诱导原代培养皮质神经元的毒性损伤,淀粉样前体蛋白-Fe65信号通路可能是其损伤机制之一。

Signal pathway of amyloid precursor protein in neuronal cell injury induced by amyloid-beta peptide 1-42

BACKGROUND:Researches in recent years show that fibrillar amyloid-β peptide 1-42 can promote the accumulation of amyloid precursor protein in cell surface and lead to nerve injury.OBJECTIVE:To explore the role of amyloid precursor protein signal pathway in neuronal cell injury induced by amyloid-β peptide 1-42.METHODS:The cortical neurons were isolated from pregnant SD rats(17 to 18 days) and cultured.On the 7th day after cultivation,the neurons were incubated with 0(normal control),0.05,0.5 and 5 mol/L fibrillar amyloid-β peptide 1-42 for 8 hours to construct cytotoxic model.Calcein content in the supernatant of neuron cell culture medium was determined by biochemical methods.The expression of amyloid precursor protein and Fe65 was detected by double-label immunofluorescence assays and western blotting.RESULTS AND CONCLUSION:Compared with the normal control group,the calcein releasing was significantly increased after incubation with different concentrations of fibrillar amyloid-β peptide 1-42 for 8 hours.The co-localization and expression of amyloid precursor protein and Fe65 increased according to western blotting and immunofluorescence,respectively.These findings indicate that fibrillar amyloid-β peptide 1-42 can induce toxic injury in primary cultured cortical neurons,and the amyloid precursor protein-Fe65 signal pathway may be one of the mechanisms of cytotoxic activity.