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

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

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。

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.