SCN2B在APP/PS1小鼠脑组织中对APP加工处理的作用  

Role of SCN2B on APP processing in APP/PS1 mouse brain tissue

作　　者：赵浩然 李珊 严国纪 董晓函 习杨彦彬 Zhao Haoran;Li Shan;Yan Guoji;Dong Xiaohan;Xiyang Yanbin(Institute of Neuroscience,Basic Medical School,Kunming Medical University,Kunming Yunnan 650500,China)

机构地区：[1]昆明医科大学基础医学院神经科学研究所,云南昆明650500

出　　处：《遵义医科大学学报》2021年第4期446-452,共7页Journal of Zunyi Medical University

基　　金：昆明医科大学认知功能障碍相关脑疾病研究科技创新团队(NO:CXTD201807)。

摘　　要：目的在遗传背景为APP/PS1(APP/PS1+)的阿尔兹海默病模式基础上对SCN2B基因进行敲除(SCN2B-/-)、敲低(SCN2B+/-)或过表达(SCN2B+/+),构建APP/PS1+SCN2B-/-、APP/PS1+SCN2B+/-以及APP/PS1+SCN2B+/+三种品系转基因小鼠,探究SCN2B在APP加工处理及Aβ产生过程中的可能作用。方法将阿尔兹海默病模式动物APP/PS1+小鼠分别与SCN2B-/-、SCN2B+/-及SCN2B+/+三种转基因小鼠杂交并获得稳定转基因品系。运用PCR技术检测品系小鼠基因型,qRT-PCR、Western blot检测SCN2B基因在各品系小鼠脑中的表达量。挑选出适龄转基因阳性小鼠获取脑皮质与海马组织进行神经元代培养,ELISA检测神经元中的Aβ40和Aβ42在脑皮质海马中的表达含量,Western blot检测APP-APPβ-CTF、sAPPα、sAPPβ蛋白含量。结果与APP/PS1+SCN2B-/-、APP/PS1+SCN2B+/-两组相比,APP/PS1+SCN2B+/+组中Aβ40和Aβ42蛋白表达增加(P<0.05);sAPPα,sAPPβ蛋白表达随SCN2B蛋白的表达升高而减少(P<0.05);而APP-APPβ-CTF与AICD的蛋白表达随SCN2B蛋白的表达升高而增加(P<0.05)。结论SCN2B基因过表达能促进APP向产生Aβ40和Aβ42片段的分解过程;促进APP分解为致病性的APP-APPβ-CTF及AICD,减少其向水溶性可代谢的sAPPα片段分解,进而部分阐明SCN2B在APP加工处理及Aβ产生中的作用。Objective To explore the role of SCN2B in the processing of APP and the production of Aβby establishing three strains of transgenic mice:APP/PS1+SCN2B-/-,APP/PS1+SCN2B+/-and APP/PS1+SCN2B+/+mice.Methods APP/PS1+transgenic mice were hybridized with SCN2B-/-,SCN2B+/-and SCN2B+/+transgenic mice,and then the stable hybridized generations were obtained.The genotypes of these hybridized generations were detected by PCR and the expression of SCN2B gene was evaluated by qRT-PCR and Western blot assays.Three successfully transgenic mice were employed for further analysis.The expression of Aβ40 and Aβ42 in cortex and hippocampus was detected by ELISA,and the protein contents of APP-APPβ-CTF,sAPPαand sAPPβwere detected by Western blot assay.In addition,the cortical and hippocampal tissues of mice with different genetic background were obtained for cell culture.Results Compared with APP/PS1+SCN2B-/-and APP/PS1+SCN2B+/-groups,the expressions of Aβ40 and Aβ42 protein increased in APP/PS1+SCN2B+/+group(P<0.05).The expressions of sAPPαand sAPPβprotein decreased with the increase of SCN2B protein expression(P<0.05).The protein expressions of APP-APPβ-CTF and AICD increased with the increase of SCN2B protein expression(P<0.05).Conclusion The over-expression of SCN2B gene could promote the decomposition of APP towards Aβ40 and Aβ42 fragments and the decomposition of APP into pathogenic APP-APPβ-CTF and AICDand reduce the decomposition of APP into water-soluble metabolizable sAPPαfragment,thus partially elucidating the role of SCN2B on APP processing and Aβproduction.

关 键 词：阿尔兹海默病 电压门控性钠通道二型β亚基 淀粉样蛋白前体蛋白APP 淀粉样蛋白Aβ 转基因小鼠 

分 类 号：R-332[医药卫生]