早老素-1基因甲基化与阿尔茨海默病的相关性研究  

Association between Presenilin 1 gene methylation and sporadic Alzheimer＇s disease

作　　者：孙蓉[1] 贾建平[2] 

机构地区：[1]中国康复研究中心神经康复K2科,北京100068 [2]首都医科大学宣武医院神经科

出　　处：《中华老年医学杂志》2014年第12期1272-1275,共4页Chinese Journal of Geriatrics

摘　　要：目的探讨早老素-1（PSENl）基因甲基化与散发性阿尔茨海默病（sAD）的相关性。方法应用MassARRAY质谱定量检测35例SAD、33例轻度认知障碍（MCI）和22名对照者PSENl基因启动子区甲基化程度。构建报告基因质粒，转染细胞，分别用血清剥夺、AD25-35、S-腺苷甲硫氨酸（SAM）及5-脱氧杂氮胞苷（5-aza-CdR）处理。检测不同处理后质粒的荧光素酶活性。结果PSENl基因在-288至＋101区域有26个甲基化位点，其中大多数Cr，G位点甲基化水平很低，平均甲基化率小于10％。与对照组相比，SAD组患者PSEN-1启动子在-173、-95和＋76的甲基化水平明显降低（P≤0．01），降低程度在10％～50％。MCI组与对照相比，启动子区各CpG位点甲基化程度的变化均差异无统计学意义（P〉0．05）。PSEN1基因启动子区平均甲基化率与年龄之间呈负性相关（r=一0．707，P〈0．01）。随着年龄的增长，甲基化水平逐渐降低。无论是在SH-SY5Y细胞中，还是在HeLa细胞中，PSEN1启动子质粒的转录活性在SAM干预下，与非处理组相比均明显下降（P〈0．01）。结论PSENl基因甲基化与SAD发病相关，PSEN1可能通过甲基化改变基因转录水平，进一步影响淀粉样蛋白7分泌酶的活性，从而导致AD发病。Objective To investigate the correlation between Presenilin 1 gene methylation （PSEN1） and sporadic Alzheimerrs disease （SAD）. Methods Massarray method was used to perform an analysis of DNA methylation in the promoters of PSEN1 gene in lymphocytes from 35 SAD patients, 33 mild cognitive impaired （MCI） patients and 22 age- and gender-matched controls. Reporter gene plasmid of PSEN1 was built by genetic recombination methods, and then transiently transfected into the SH-SY5Y and HeLa cells. After that, cells were treated with several agents including serum deprivation, A1325-35, 5-aza-2＇-deoxycytidine （5-aza-Cdr） and S-adenosyl-L- methionine （SAM）. A dual-luciferase reporter assay system was used to calculate the relative luciferase activity （RLA）. Results Some CpG sites of PSEN1 （Cytosines at-173,-95 and ＋76） showed hypomethyiation patterns in SAD cases as compared with MCI and control group （P〈0.01）. A dual-luciferase reporter assay showing significant differences in PSEN1 transcription activities were found in both cell lines under SAM treatment [SY5Y, SAM： （6.40±0.81）, control： （9.13±1.67）, P=0.000; Hela, SAM： （2.06±0.34）, control： （2.99±0.59）, P=0.000]. Conclusions DNA hypomethylation of PSEN1 gene promoter is significantly associated with SAD susceptibility. PSEN1 may change the gene transcription level by methylation, further affecting the activity of amyloid protein -like γ-secretase, leading to the onset of AD.

关 键 词：阿尔茨海默病 早老素1 甲基化 

分 类 号：R749.16[医药卫生—神经病学与精神病学]