Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan.
Crit Care Med. 2010 Jan;38(1):217-22. doi: 10.1097/CCM.0b013e3181b4a854.
Sarcoplasmic reticulum Ca-ATPases (SERCA2a) plays an essential role in the Ca homeostasis and cardiac functions. Tumor necrosis factor-alpha (TNF-alpha) decreases the SERCA2a, which may underlie cardiac dysfunction during sepsis and heart failure. Because the promoter region of SERCA2a contains CpG islands, gene methylation should be critical in regulating SERCA2a. The present study was to evaluate whether TNF-alpha can modulate SERCA2a via enhancing methylation and to investigate the underlying mechanisms.
Controlled laboratory experiment.
University research laboratory.
HL-1 cardiomyocytes.
TNF-alpha (1-50 ng/mL) was administered in HL-1 cardiomyocytes with and without co-administration of an NF-kappaB inhibitor (SN-50, 50 microg/mL), antioxidant agents (ascorbic acid, 100 microM, or coenzyme Q10, 10 microM), or methylation inhibitor (5-aza-2'-deoxycytidine, 0.1, 1 microM).
TNF-alpha (50 ng/mL) decreased the SERCA2a RNA and protein by quantitative polymerase chain reaction and immunoblot. Furthermore, TNF-alpha (50 ng/mL) increased the methylation in the SERCA2a promoter region, which was not influenced by the co-administration of SN-50, ascorbic acid, or coenzyme Q10, but was attenuated by 5-aza-2'-deoxycytidine (0.1 microM). Additionally, TNF-alpha (50 ng/mL) increased the expression of DNA methyltransferase 1.
TNF-alpha increased DNA methyltransferase levels, thus enhancing the methylation in the SERCA2a promoter region with a result of reducing SERCA2a. These findings suggest that inhibition of hypermethylation may be a novel treatment strategy for cardiac dysfunction.
肌浆网 Ca2+-ATP 酶（SERCA2a）在 Ca2+稳态和心脏功能中起着至关重要的作用。肿瘤坏死因子-α（TNF-α）可降低 SERCA2a，这可能是脓毒症和心力衰竭期间心脏功能障碍的基础。由于 SERCA2a 的启动子区域含有 CpG 岛，因此基因甲基化对于调节 SERCA2a 应该是至关重要的。本研究旨在评估 TNF-α 是否可以通过增强甲基化来调节 SERCA2a，并研究其潜在机制。
对照实验室实验。
大学研究实验室。
HL-1 心肌细胞。
HL-1 心肌细胞给予 TNF-α（1-50ng/ml），并与 NF-κB 抑制剂（SN-50，50μg/ml）、抗氧化剂（抗坏血酸，100μM，或辅酶 Q10，10μM）或甲基化抑制剂（5-氮杂-2′-脱氧胞苷，0.1，1μM）共同给药。
TNF-α（50ng/ml）通过定量聚合酶链反应和免疫印迹降低 SERCA2a RNA 和蛋白质。此外，TNF-α（50ng/ml）增加了 SERCA2a 启动子区域的甲基化，这不受 SN-50、抗坏血酸或辅酶 Q10 共同给药的影响，但被 5-氮杂-2′-脱氧胞苷（0.1μM）减弱。此外，TNF-α（50ng/ml）增加了 DNA 甲基转移酶 1 的表达。
TNF-α 增加了 DNA 甲基转移酶的水平，从而增强了 SERCA2a 启动子区域的甲基化，导致 SERCA2a 减少。这些发现表明，抑制过度甲基化可能是治疗心脏功能障碍的一种新策略。
