中文摘要：

目的研究细胞复制衰老与H2O2诱导细胞早衰过程中P66^SHC基因表达变化及复制衰老过程中组蛋白修饰改变。方法人胚肺成纤维细胞固定传代直至停止增殖以制备复制衰老模型，过氧化氢诱导细胞早衰模型。采用Q-PCR方法动态观察细胞复制衰老与早衰过程中P66^SHC以及组蛋白乙酰化酶EP300和去乙酰化酶HDAC1的基因表达，采用染色质免疫沉淀技术观察年轻细胞与衰老细胞P66^SHC基因启动子区的组蛋白修饰情况。结果P66^SHC mRNA表达与染毒剂量正相关（R=0．909，P=0．000），EP300表达与染毒剂量负相关（R=-0．922，P=0．000），HDAC1与染毒剂量不相关（R=-0．066，P=0．839）。P66^SHC表达与群体倍增代数正相关（R=0．743，P=0．006），EP300表达和HDAC1表达与群体倍增代数负相关（R=-0．709，P=0．010；R=-0．599，P=0．040）。与复制衰老组相比，早衰组细胞P66^SHC、EP300及HDACl的基因表达量均有显著性差异（t=-19．733，P=0．000；t=11．103，P=0．000；t=9．728，P=0．001）。老年细胞的P66^SHC基因调控区的H3组蛋白修饰丰度均降低；在转录起始点上游3．0kb处抑制基因转录的H3K9-tri—Me修饰几乎为零，选择启动子（转录起始点下游3．8kb）处的组蛋白修饰以活化转录的修饰为主。结论P66^SHC、EP300和HDACl均可能参与细胞衰老和氧化应激诱导的细胞早衰，早衰组细胞P66^SHC基因表达与复制衰老组不同；组蛋白修饰参与P66^SHC的基因表达调控。

英文摘要：

Objective To study the profile of P66^SHC expression and histone modifications in replicatively senescenct cells and oxidative-stress inducing premature senescenct cells. Methods HPF cells were continuously cultured and subcuhured in vitro to build replicative cellular model. HPF cells were treated with 200 μmol/L H202 four times to build oxidative-stress inducing premature senescenct model. Comparative Q-PCR was utilized to investigate target gene（P66^SHC ,EP300 ,HDAC1 ）expressions respectively in H2O2 treated groups and normal cell groups. Then CHIP-QPCR was conducted to analyze histone modifications of P66^SHC between young cells and aging cells. Results P66^SHC expression was positive correlation with H2O2 doses and population doubling level （PDL） （R = 0. 909, P = 0. 000 ; R = 0. 743, P = 0. 006 ） , while EP300 was negative correlation with H202 （R = - 0. 922, P = 0. 000） and both EP300 and HDAC1 were negative with PDL （R = -0. 709,P =0. 010,R = -0. 599,P =0. 040）. H3 histone modifications were declined in P66^SHC gene regulating region. H3-Ac, H3K9-Ac and H3K4-tri-Me were dominant in the upstream region of transcriptional site （ - 3.0 kb） and alternative promotor （ ＋ 3.8 kb）. Conclusion P66^SHC, EP300 and HDAC1 probably play a role in cellular replicative senescence and oxidative-stress inducing premature senescence. Besides, histone modification could regulate P66^SHC gene expression.