Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Lab Invest. 2011 Sep;91(9):1291-7. doi: 10.1038/labinvest.2011.92. Epub 2011 Jul 11.
Sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a) plays an essential role in Ca(2+) homeostasis and cardiac functions. The promoter region of SERCA2a has a high content of CpG islands; thus, epigenetic modification by inhibiting methylation can enhance SERCA2a expression in cardiomyocytes. Hydralazine, a drug frequently used in heart failure, is a potential DNA methylation inhibitor. We evaluated whether hydralazine can modulate Ca(2+) handling through an increase in SERCA2a expression via regulating methylation. We used indo-1 fluorescence, real-time RT-PCR, immunoblotting, and methylation-specific PCR to investigate intracellular Ca(2+), the expressions of RNA and protein, and methylation of SERCA2a in HL-1 cardiomyocytes with and without (control) the administration of hydralazine (1, 10, and 30 μM) for 72 h. Hydralazine (10 and 30 μM) increased the intracellular Ca(2+) transients and SR Ca(2+) contents. Hydralazine (10 and 30 μM) decreased methylation in the SERCA2a promoter region and increased the RNA and protein expressions of SERCA2a. Additionally, hydralazine (10 and 30 μM) decreased the expression of DNA methyltransferase 1. Moreover, treatment with hydralazine in isoproterenol-induced heart failure rats decreased the promoter methylation of SERCA2a and increased SERCA2a RNA expression. In conclusion, hydralazine-induced promoter demethylation may improve cardiac function through increasing SERCA2a and modulating calcium homeostasis in cardiomyocytes.
肌浆网 Ca(2+)-ATP 酶（SERCA2a）在 Ca(2+) 稳态和心脏功能中起着至关重要的作用。SERCA2a 的启动子区域含有高含量的 CpG 岛；因此，通过抑制甲基化的表观遗传修饰可以增强心肌细胞中 SERCA2a 的表达。肼屈嗪是心力衰竭中常用的一种药物，是一种潜在的 DNA 甲基化抑制剂。我们评估了肼屈嗪是否可以通过调节甲基化来增加 SERCA2a 的表达来调节 Ca(2+) 处理。我们使用 indo-1 荧光、实时 RT-PCR、免疫印迹和甲基化特异性 PCR 来研究 HL-1 心肌细胞中的细胞内 Ca(2+)、RNA 和蛋白质的表达以及 SERCA2a 的甲基化，这些细胞在没有（对照）和有（处理）肼屈嗪（1、10 和 30 μM）治疗 72 小时的情况下。肼屈嗪（10 和 30 μM）增加了细胞内 Ca(2+) 瞬变和 SR Ca(2+) 含量。肼屈嗪（10 和 30 μM）降低了 SERCA2a 启动子区域的甲基化，并增加了 SERCA2a 的 RNA 和蛋白质表达。此外，肼屈嗪（10 和 30 μM）降低了 DNA 甲基转移酶 1 的表达。此外，在异丙肾上腺素诱导的心力衰竭大鼠中用肼屈嗪治疗降低了 SERCA2a 的启动子甲基化并增加了 SERCA2a RNA 表达。总之，肼屈嗪诱导的启动子去甲基化可能通过增加 SERCA2a 并调节心肌细胞中的钙稳态来改善心脏功能。
