Signal Transduction Laboratory, NIEHS, NIH, DHHS, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
Cellular and Molecular Pathology Branch, NIEHS, NIH, DHHS, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
Sci Signal. 2019 Apr 16;12(577):eaau9685. doi: 10.1126/scisignal.aau9685.
Stress is increasingly associated with heart dysfunction and is linked to higher mortality rates in patients with cardiometabolic disease. Glucocorticoids are primary stress hormones that regulate homeostasis through two nuclear receptors, the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR), both of which are present in cardiomyocytes. To examine the specific and coordinated roles that these receptors play in mediating the direct effects of stress on the heart, we generated mice with cardiomyocyte-specific deletion of GR (cardioGRKO), MR (cardioMRKO), or both GR and MR (cardioGRMRdKO). The cardioGRKO mice spontaneously developed cardiac hypertrophy and left ventricular systolic dysfunction and died prematurely from heart failure. In contrast, the cardioMRKO mice exhibited normal heart morphology and function. Despite the presence of myocardial stress, the cardioGRMRdKO mice were resistant to the cardiac remodeling, left ventricular dysfunction, and early death observed in the cardioGRKO mice. Gene expression analysis revealed the loss of gene changes associated with impaired Ca handling, increased oxidative stress, and enhanced cell death and the presence of gene changes that limited the hypertrophic response and promoted cardiomyocyte survival in the double knockout hearts. Reexpression of MR in cardioGRMRdKO hearts reversed many of the cardioprotective gene changes and resulted in cardiac failure. These findings reveal a critical role for balanced cardiomyocyte GR and MR stress signaling in cardiovascular health. Therapies that shift stress signaling in the heart to favor more GR and less MR activity may provide an improved approach for treating heart disease.
压力与心脏功能障碍的关系越来越密切,与患有心脏代谢疾病的患者的死亡率升高有关。糖皮质激素是主要的应激激素,通过两种核受体,即糖皮质激素受体 (GR) 和盐皮质激素受体 (MR),来调节体内平衡,这两种受体都存在于心肌细胞中。为了研究这些受体在介导应激对心脏的直接影响方面的具体和协调作用,我们生成了心肌细胞特异性缺失 GR(cardioGRKO)、MR(cardioMRKO)或 GR 和 MR(cardioGRMRdKO)的小鼠。cardioGRKO 小鼠自发发生心肌肥厚和左心室收缩功能障碍,并因心力衰竭而过早死亡。相比之下,cardioMRKO 小鼠表现出正常的心脏形态和功能。尽管存在心肌应激,但 cardioGRMRdKO 小鼠对 cardioGRKO 小鼠中观察到的心脏重构、左心室功能障碍和早期死亡具有抗性。基因表达分析揭示了与 Ca 处理受损、氧化应激增加以及细胞死亡增强相关的基因变化的丧失,以及限制肥厚反应并促进双敲除心脏中心肌细胞存活的基因变化的存在。在 cardioGRMRdKO 心脏中重新表达 MR 逆转了许多心脏保护基因变化,并导致心力衰竭。这些发现揭示了平衡的心肌细胞 GR 和 MR 应激信号在心血管健康中的关键作用。将心脏中的应激信号转移到有利于更多 GR 和更少 MR 活性的疗法可能为治疗心脏病提供一种改进的方法。