衰老细胞中热休克转录因子1的异常调节和定位  

Aberrant Regulation and Localization of Heat Shock Factor 1 in Senescent Human Diploid Fibroblasts

作　　者：林正[1] 张式鸿[1] 罗兰[1] 黄帆[1] 吴兴刚[1] 徐康[1] 马中富[1] 

机构地区：[1]中山大学附属第一医院中心实验室,广州510080

出　　处：《中国生物化学与分子生物学报》2006年第2期129-134,共6页Chinese Journal of Biochemistry and Molecular Biology

基　　金：国家自然科学基金(No.30070829);广东省自然科学基金资助项目(No.5001731)~~

摘　　要：为评估人热休克转录因子1(HSF1)在衰老细胞中呈现年龄依赖功能失调机制,通过凝胶电泳迁移率改变实验(EMSA)和RNA酶保护实验等了解低总体倍增水平(PDLs)的年轻和高PDLs的衰老IMR90双倍体人肺纤维母细胞的HSF1 DNA结合活性、HSF1蛋白质及其编码转录子mRNA水平和亚细胞分布.使用H2O2诱导年轻IMR90细胞成为“应激诱导早熟性老化(SIPS)”细胞,并与复制性衰老细胞比较HSF1 DNA结合活性、HSF1亚细胞分布和细胞内过氧化物含量.在不同年龄的IMR90细胞中,无论体内或体外,HSF1激活能力与细胞年龄呈反相关,但细胞内HSF1蛋白质与其mRNA水平并无改变.HSF1的亚细胞定位分析显示,HSF1主要存在于年轻细胞胞质中,热刺激促使三体形成和核转移;而在衰老细胞中,37℃时HSF1大部分存在于细胞核内,热刺激后形成三体,与DNA结合能力明显比年轻细胞弱;用H2O2诱导的应激成熟前老化细胞内,HSF1功能和亚细胞分布都与复制性衰老细胞相似.结果显示,细胞年龄与HSF1的激活和定位相关,而与HSF1含量无关,这些变化可能是通过氧化修饰所致.The goal of this study is to elucidate the mechanism（s） of stress-induced activation of heat shock factor 1 （HSF1） and induction of heat shock proteins were attenuated in aging human diploid fibroblasts. Using IMR-90 human diploid fibroblasts, EMSA assay showed that while the ability of the latent HSF1 to be activated in vivo and in vitro was inversely proportional to the age of the cell, the abundance of HSF1 protein and mRNA were unchanged. Analysis of cytosolic versus nuclear localization of HSF1 showed that in young cells HSFI was primary cytosolic, and heat shock promoted its trimerization and nuclear translocation. In old cells, a significant portion of the HSF1 protein was sequestered in the nucleus at 37℃. While heat shock promoted the phosphorylation and nuclear translocation of HSF1, the ability of this nucleus- localized HSF1 to form the DNA-binding trimer was reduced. Similar changes in HSF1 were also observed in H2O2 induced prematurely senescent cells. The measurement of peroxide content by flow cytometry showed a higher level in old cells compared to young cells and in H2O2 pretreated cells compared to the control. The results demonstrated dynamic age dependent changes in the regulation and localization but not the steady state level of HSFI, these changes were likely to be mediated by oxidative events.

关 键 词：热休克转录因子1 衰老 氧化作用 调节与定位 

分 类 号：R393.23[医药卫生—基础医学]