The Key Laboratory of Geriatrics, Beijing Hospital and Beijing Institute of Geriatrics, Ministry of Health, Beijing 100730, China.
The Second Hospital of Shanxi Medical University, Taiyuan 030001, China ; Department of Cardiology, The General Hospital of Jincheng Anthracite Mining Group Co. Ltd., Jincheng 048006, China.
Oxid Med Cell Longev. 2014;2014:713894. doi: 10.1155/2014/713894. Epub 2014 Dec 29.
Sirtuin 1 (SIRT1) is a member of the sirtuin family, which could activate cell survival machinery and has been shown to be protective in regulation of heart function. Here, we determined the mechanism by which SIRT1 regulates Angiotensin II- (AngII-) induced cardiac hypertrophy and injury in vivo and in vitro.
We analyzed SIRT1 expression in the hearts of control and AngII-induced mouse hypertrophy. Female C57BL/6 mice were ovariectomized and pretreated with 17β-estradiol to measure SIRT1 expression. Protein synthesis, cardiomyocyte surface area analysis, qRT-PCR, TUNEL staining, and Western blot were performed on AngII-induced mouse heart hypertrophy samples and cultured neonatal rat ventricular myocytes (NRVMs) to investigate the function of SIRT1.
SIRT1 expression was slightly upregulated in AngII-induced mouse heart hypertrophy in vivo and in vitro, accompanied by elevated cardiomyocyte apoptosis. SIRT1 overexpression relieves AngII-induced cardiomyocyte hypertrophy and apoptosis. 17β-Estradiol was able to protect cardiomyocytes from AngII-induced injury with a profound upregulation of SIRT1 and activation of AMPK. Moreover, estrogen receptor inhibitor ICI 182,780 and SIRT1 inhibitor niacinamide could block SIRT1's protective effect.
These results indicate that SIRT1 functions as an important regulator of estrogen-mediated cardiomyocyte protection during AngII-induced heart hypertrophy and injury.
Sirtuin 1(SIRT1)是 Sirtuin 家族的一员,它可以激活细胞存活机制,并已被证明在调节心脏功能方面具有保护作用。在这里,我们确定了 SIRT1 在体内和体外调节血管紧张素 II-(AngII-)诱导的心肌肥厚和损伤的机制。
我们分析了对照和 AngII 诱导的小鼠肥厚心脏中 SIRT1 的表达。雌性 C57BL/6 小鼠被卵巢切除,并使用 17β-雌二醇预处理,以测量 SIRT1 的表达。对 AngII 诱导的小鼠心脏肥厚样本和培养的新生大鼠心室肌细胞(NRVMs)进行蛋白质合成、心肌细胞表面积分析、qRT-PCR、TUNEL 染色和 Western blot,以研究 SIRT1 的功能。
SIRT1 的表达在体内和体外 AngII 诱导的小鼠心脏肥厚中略有上调,伴随着心肌细胞凋亡的增加。SIRT1 的过表达缓解了 AngII 诱导的心肌细胞肥大和凋亡。17β-雌二醇能够通过显著上调 SIRT1 和激活 AMPK 来保护心肌细胞免受 AngII 诱导的损伤。此外,雌激素受体抑制剂 ICI 182,780 和 SIRT1 抑制剂烟酰胺可以阻断 SIRT1 的保护作用。
这些结果表明,SIRT1 作为雌激素介导的心肌细胞保护在 AngII 诱导的心脏肥厚和损伤过程中的重要调节因子发挥作用。