组蛋白H3高乙酰化对心脏相关转录因子Islet-1的调控作用

Effects of acetylation of histone H3 on the regulation of transcription factor Islet-1 in cardiac progenitor cells

目的:探讨组蛋白H3乙酰化修饰对心脏发育早期相关转录因子胰岛素基因增强结合蛋白1(Insulin gene enhancerprotein 1,Islet-1)的调控作用。方法:体外培养心肌祖细胞,分别用不同浓度组蛋白去乙酰化酶抑制剂辛二酰苯胺异羟肟酸(Suberoylanilide hydroxamic acid,SAHA)干预(0、0.5、1.0、2.0、4.0μmol/L),噻唑蓝(Methyl thiazoyl tetrazolium,MTT)比色实验检测SAHA对细胞增殖的影响,筛选出SAHA的合适干预浓度,用Western blot技术检测心肌祖细胞组蛋白H3乙酰化状态,Real-time PCR检测Islet-1的mRNA表达水平变化,染色质免疫共沉淀(Chromatin immunoprecipitation,ChIP)Real-timePCR技术检测Islet-1启动子区组蛋白H3的乙酰化水平。结果:SAHA 0.5、1.0μmol/L处理组较对照组细胞增殖率有所提高,但差异没有统计学意义(P>0.05),SAHA 2.0μmol/L处理组与对照组细胞增殖率相当(P>0.05)。SAHA 4.0μmol/L处理组与对照组比较,细胞增殖受到抑制(P<0.05)。SAHA 2.0μmol/L处理48 h后心肌祖细胞H3乙酰化水平与对照组比升高7.23倍(P<0.05)。Islet-1的mRNA表达与对照组比提高了4.68倍(P<0.05),Islet-1启动子区组蛋白H3乙酰化水平是对照组的2.08倍(P<0.05)。结论:在心肌祖细胞中,组蛋白H3高乙酰化水平促进Islet-1表达,Islet-1受到组蛋白H3乙酰化调控。

Objective：To investigate the effects of acetylation of histone H3 on the regulation of heart development-related transcription factor insulin gene enhancer protein 1（Islet-1）.Methods：Cardiac progenitor cells were cultured in vitro and were treated with histone deacetylase inhibitor suberoylanilide hydroxamic acid（SAHA） at concentration of 0.5,1.0,2.0,4.0 μmol/L.Methyl thiazoyl tetrazolium（MTT） assay was used to detect the effect of SAHA on cell proliferation and to select suitable intervention concentration.Western blot was applied to detect the acetylation of histone H3 and Real-time PCR was employed to measure the mRNA expression of Islet-1.Chromatin Immunoprecipitation（ChIP）Real-time PCR was used to measure the level of the acetylation of histone H3 in promoter region of Islet-1.Results：The cell proliferation rate of SAHA was increased in 0.5 μmol/L and 1.0 μmol/L group than in control group but without siganificant difference（P 0.05）.No difference in the cell proliferation rate was found between SAHA 2.0 μmol/L group and control group（P〉0.05）.The cell proliferation in SAHA in 4.0 μmol/L group was greatly affected（P〉0.05）.Western blot showed that the acetylation of histone H3 was increased by 7.23 fold in SAHA 2.0 μmol/L group after 48 h（P〈0.05）.The expression of Islet-1 was increased by 4.68 fold（P〈0.05）,and the level of the acetylation of histone H3 in promoter region of Islet-1 was increased to 2.08 fold（P〈0.05） compared with those in control group.Conclusion：The expression of Islet-1 can be promoted by increasing of the acetylation of histone H3 in promoter region of Islet-1.The expression of Islet-1 is regulated by the acetylation of histone H3 in cardiac progenitor cells.