摘要
目的 探讨N-乙酰半胱氨酸（NAC）对凝聚态β淀粉样蛋白毒性片段25-35（Aβ25-35）诱导tau蛋白过度磷酸化的影响及可能机制.方法 运用凝聚态Aβ25-35来诱导皮质神经元的tau蛋白过度磷酸化,实验分为空白对照组、Aβ组、NAC与Aβ共同作用组,采用荧光酶标法检测氧自由基（ROS）,用Western印迹方法测定p35/p25亚基、cdk5亚基、磷酸化Thr205和磷酸化Ser404位点水平.结果 凝聚态Aβ25-35（20μmol/L）作用12 h可使得ROS明显升高（218±28比371±31,t=-6.35,P＜0.05）以及tau蛋白在T205（1.00±0.20比1.67±0.12,t=-5,P＜0.05）和S404（1.00±0.02比1.70 ±0.26,t=-4.57,P＜0.05）位点磷酸化水平明显升高;与Aβ处理组相比,NAC（10 mmol/L）预先作用24h然后再与凝聚态Aβ25-35共同作用12 h,ROS水平下降至286±29（t =3.47,P＜0.05）和tau蛋白在T205（1.23±0.12,=3.88,P＜0.05）和S404（1.13±0.06,t=3.64,P＜0.05）位点磷酸化水平皆明显下降;另外,与空白对照组（1.00±0.19）相比,Aβ处理组中的p25水平明显升高（1.83±0.15,t=-6.20,P＜0.05）;而与Aβ处理组相比,NAC预处理组中的p25水平下降（1.23±0.06）,差异皆有统计学意义（t=4.72,P＜0.05）.结论 NAC可通过CDK5信号通路减轻凝聚态Aβ25-35诱导的神经元tau蛋白过度磷酸化.
Objective To investigate the possible effect and mechanism of N-Acetyl-L-cysteine （NAC） on fibrillar Aβ （25-35）-induced tau hyperphosphorylation.Methods The phosphorylation of tau was induced by Aβ（25-35） in primary cortical neuron.Neurons were incubated in the absent or present Aβ （25-35）,or pre-incubated NAC then co-incubated in Aβ.The measurement of ROS was performed on a microplate fluorometer.The proteins of p35/p25,cdkS,pT205 and pS404 were detected by Western blot.Results In A[β treated group,the ROS,pT205 and pS404 level were obviously higher than that in nontreated with Aβ group for 12 h （t =-6.35,P 〈0.05; t =-5,P 〈0.05; t =-4.57,P 〈0.05）.However,in neurons pre-incubated with （10 mmol/L） NAC and then co-incubated with 20 μmol/L Aβ,the ROS,pT205 and pS404 level were significantly decreased compared with that of Aβ group （t =3.47,P 〈 0.05; t =3.88,P〈0.05 and t =3.64,P〈0.05） ; Upon Aβ exposure for 12 h,cortical neurons showed a statistically significant increase in p25 when compared to the control group （t =-6.20,P 〈 0.05）.However,pre-treatment with NAC showed a decrease in p25 as compared to neurons treated with Aβ alone for 12 h （t =4.72,P 〈 0.05）.Conclusion NAC attenuated the Aβ （25-35）-induced tau hyperphosphorylation through CDK5 pathway.
出处
《中华医学杂志》
CAS
CSCD
北大核心
2015年第33期2701-2704,共4页
National Medical Journal of China
基金
国家自然科学基金（81100812）
福建省医学创新课题（2012-CX-15）
福建省自然科学基金（2013J01311）
