Hornocysteine inhibits endothelial cell growth via DNA hypomethylation of the cyclin A gene
Hornocysteine inhibits endothelial cell growth via DNA hypomethylation of the cyclin A gene
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DOI：
10.1182/blood-2007-06-096701
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发表时间：
2007-11-15
期刊：
影响因子：
20.3
通讯作者：
Wang, Hong
中科院分区：
文献类型：
--
作者：
Jamaluddin, Md S.;Chen, Irene;Wang, Hong
我们以前报道过，同型半胱氨酸（Hcy）抑制内皮细胞（EC）的生长通过转录抑制细胞周期蛋白A基因通过低甲基化相关的机制。在这项研究中，我们研究了同型半胱氨酸对细胞周期蛋白A基因表观遗传修饰的影响及其在人类EC中的生物学作用。Hcy和DNA甲基转移酶抑制剂显著抑制细胞周期蛋白A mRNA水平。细胞周期蛋白A启动子含有一个跨越477-bp区域（~ 277/200）的CpG岛。亚硫酸氢盐测序和聚合酶链反应（PCR）扩增细胞周期蛋白A启动子（-267/37）表明，Hcy消除了细胞周期蛋白A启动子中2个CpG位点的甲基化，其中一个位于细胞周期依赖元件（CDE）上。CDE上CG序列的突变导致启动子活性增加6倍。Hcy抑制DNA甲基转移酶1（DNMT 1）活性30%，并减少甲基CpG结合蛋白2（MeCP 2）的结合，增加乙酰化组蛋白H3和H4在细胞周期蛋白A启动子中的结合。最后，腺病毒转导的DNMT 1基因表达逆转了同型半胱氨酸对细胞周期蛋白A表达和EC生长抑制的抑制作用。总之，Hcy通过抑制内皮细胞中DNMT 1抑制DNA甲基化来抑制细胞周期蛋白A的转录和细胞生长。
We reported previously that homocysteine (Hcy) inhibits endothelial cell (EC) growth by transcriptional inhibition of the cyclin A gene via a hypomethylation-related mechanism. In this study, we examined the effect of Hcy on epigenetic modification of the cyclin A gene and its biologic role in human ECs. Cyclin A mRNA levels were significantly suppressed by Hcy and a DNA methyltransferase inhibitor. The cyclin A promoter contains a CpG island spanning a 477-bp region (-277/200). Bisulfite sequencing followed by polymerase chain reaction (PCR) amplification of the cyclin A promoter (-267/37) showed that Hcy eliminated methylation at 2 CpG sites in the cyclin A promoter, one of which is located on the cycle-dependent element (CDE). Mutation of CG sequence on the CDE leads to a 6-fold increase in promoter activity. Hcy inhibited DNA methyltransferase 1 (DNMT1) activity by 30%, and reduced the binding of methyl CpG binding protein 2 (MeCP2) and increased the bindings of acetylated histone H3 and H4 in the cyclin A promoter. Finally, adenovirus-transduced DNMT1 gene expression reversed the inhibitory effect of Hcy on cyclin A expression and EC growth inhibition. In conclusion, Hcy inhibits cyclin A transcription and cell growth by inhibiting DNA methylation through suppression of DNMT1 in ECs.