α7尼古丁受体基因抑制对SH—SY5Y细胞β淀粉样蛋白生成的影响

Influence of inhibited α7 nicotinic acetyicholine receptor gene expression on the production of β-amyioid peptide in SH-SY5Y cells

目的通过RNA干扰技术抑制神经母细胞瘤细胞（SH-SY5Y细胞）中胡神经型尼古丁乙酰胆碱受体（nAChR）的基因表达，以了解α7nAChR对β淀粉样蛋白（AB）的影响，进一步探讨阿尔茨海默病的发病机制。方法SH-SY5Y细胞转染α7nAChR的小干扰RNA（siRNA），用real-timePCR法和蛋白免疫印迹法分别测定细胞中α7nAChR、β分泌酶两个亚型（BACE1和BACE2）在mRNA和蛋白表达水平的变化；用双抗体夹心酶联免疫吸附法测定Aβ1-42含量的变化。结果转染α7nAChRsiRNA后，与对照组相比，α7nAChRmRNA及蛋白表达水平分别降低了84％和79％（P〈0．01）；BACElmRNA及蛋白表达水平分别升高了527％和71％（P〈0．01）；BACE2mRNA及蛋白表达水平分别降低了58％和75％（P〈0．01）；Aβ1-42含量升高了208％（P〈0．01）。结论α7nAChR基因表达抑制后Aβ含量明显升高，其机制可能与BACE1表达上升和BACE2表达抑制有关，这种改变可能与阿尔茨海默病的发病有一定的关系。

Objective To investigate the influence of inhibited α7 neuronal nicotinic acetylcholine receptor （nAChR） by small interference RNA （siRNA） in SH-SYSY cells and to explore the connection of these changes with the β-amyloid precursor protein （APP） metabolism and the pathogenesis of Alzheimer＇s disease （AD）. Methods The siRNA of α7 nAChR was transfected into SH-SY5Y cells, and the expression of α7 nAChR and two subtypes of β-secretases （ BACE1 and BACE2） at mRNA and protein levels was studied by real-time PCR and Western blot, respectively. The variation of A β1-42 content was detected by ELISA. Results As compared with controls, the expression of α7 nAChR at mRNA and protein levels in the SH-SYSY cells transfected with the α7 nAChR siRNA were decreased by 84% and 79% （P 〈 0. 01 ）, respectively. The expressions of BACE1 mRNA and protein levels was increased by 527% and 71% （P 〈 0. 01 ）, respectively, while the expression of BACE2 decreased by 58% and 75% （P 〈 0. 01 ）, respectively. The A β1-42 content increased by 208% （ P 〈 0. 01 ）. Conclusions An inhibited α7 nAChR mRNA induced by siRNA may markedly stimulate the production of A β through the mechanism of increased expression of BACE1 and inhibited expression of BACE2, which may be related to the pathogenesis of AD.