CAJ | 학술논문

目的通过胰岛素和磷脂酰肌醇-3激酶(PDK)抑制剂渥曼青霉素(wortmannin,WORT)对PI3K/丝氨酸苏氨酸蛋白激酶(PDK/Akt)信号通路的激活和抑制作用,观察PI3K/Akt信号通路对海马神经元B-淀粉样前体蛋白裂解酶1(BACE1)表达的影响.方法 40只SD大鼠随机分为空白对照组、假手术组、胰岛素组和WORT组(每组10只),海马立体定向注射胰岛素和PI3K抑制剂WORT.免疫组织化学和Western blot法检测PI3K/Akt信号传导相关蛋白以及BACE1的表达水平.结果注射胰岛素的海马PI3K信号通路下游信号分子较对照组:Akt表达增加(0.952±0.060与0.835±0.029,t=4.9150,P=0.0001),Akt set473位点磷酸化(pAkt)水平上调(0.800±0.075与0.657±0.025,t=4.5598,P=0.0002),糖原合成激酶-3α(GSK-3α)磷酸化水平降低(0.604±0.062与0.726±0. 041,t=3.5871,P=0.0018),而成熟的BACE1及其裂解产物β分泌酶C末端(β-CTF)表达下调.WORT组的PI3K下游信号分子Akt、pAkt表达明显被抑制,磷酸化GSK-3α表达增加,同时成熟的BACE1(1.004±0.096)和β-CTF(1.031±0.048)的表达较对照组(分别0.498±0.064,0.786±0.101)上调(分别t=11.5980,P=0.0000;t=4.2194,P=0.0004).结论胰岛素信号通路PI3K/AKt可以调节BACE1的表达和活性并参与阿尔茨海默病的发病机制.
목적 통과이도소화린지선기순-3격매(PDK)억제제악만청매소(wortmannin,WORT)대PI3K/사안산소안산단백격매(PDK/Akt)신호통로적격활화억제작용,관찰PI3K/Akt신호통로대해마신경원B-정분양전체단백렬해매1(BACE1)표체적영향.방법 40지SD대서수궤분위공백대조조、가수술조、이도소조화WORT조(매조10지),해마입체정향주사이도소화PI3K억제제WORT.면역조직화학화Western blot법검측PI3K/Akt신호전도상관단백이급BACE1적표체수평.결과 주사이도소적해마PI3K신호통로하유신호분자교대조조:Akt표체증가(0.952±0.060여0.835±0.029,t=4.9150,P=0.0001),Akt set473위점린산화(pAkt)수평상조(0.800±0.075여0.657±0.025,t=4.5598,P=0.0002),당원합성격매-3α(GSK-3α)린산화수평강저(0.604±0.062여0.726±0. 041,t=3.5871,P=0.0018),이성숙적BACE1급기렬해산물β분비매C말단(β-CTF)표체하조.WORT조적PI3K하유신호분자Akt、pAkt표체명현피억제,린산화GSK-3α표체증가,동시성숙적BACE1(1.004±0.096)화β-CTF(1.031±0.048)적표체교대조조(분별0.498±0.064,0.786±0.101)상조(분별t=11.5980,P=0.0000;t=4.2194,P=0.0004).결론 이도소신호통로PI3K/AKt가이조절BACE1적표체화활성병삼여아이자해묵병적발병궤제.
Objective To investigate the effect of phosphatidylinesitol-3 kinase/serine threonine kinase (PI3K/Akt) signaling pathway on expression of beta-site amyloid precursor protein cleaving enzyme-1 (BACE1) in the hippocampus neurons of rat brain. Methods Forty SD rats were randomly divided into 4 groups: blank control group, sham-operated group, insulin group and wortmannin group. Insulin or the specific inhibitor of PI3K, wortmannin was injected into hippocampus neurons to activate or inhibit the signaling pathway in insulin group or wortmannin group, respectively. Immunoprecipitation and Western blot were used to analyze the proteins levels of PI3K/Akt and BACE1. Results In insulin treatment group,among the proteins downstream of signaling pathway, expression of Akt increased (0. 952±0.060 vs 0.835±0.029,t=4.9150, P=0.0001), phospho-Akt set473 increased (0.800±0.075 vs 0.657± 0.025,t=4.5598, P=0.0002), phospho-GSK-3α decreased (0.604±0.062 vs 0.726±0.041, t= 3.5871, P=0.0018 ), and the expression of mature BACE1 and β-CTF significantly decreased. In wortmannin group, the expression of Akt and phospho-Akt ser473 were inhibited; phospho-GSK-3α increased ; mature BACEI (1.004±0.096) and β-CTF (1.031±0.048) increased (t=11.5980, P= 0.0000 and t =4.2194, P =0.0004, respectively). Conclusions PI3K/Akt signaling pathway might effect the expression of BACE1, in which impaired signaling pathway may cause the amyloid precursor protein to be easily processed by BACE1, and thus involves the pathology of Alzheimer' s disease.