Wang Yuan, Zhang Yuannyu, Ding Guanqiao, May Herman I, Xu Jian, Gillette Thomas G, Wang Hang, Wang Zhao V
Division of Cardiology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas.
State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, Sichuan, China; and.
Am J Physiol Heart Circ Physiol. 2017 Dec 1;313(6):H1119-H1129. doi: 10.1152/ajpheart.00284.2017. Epub 2017 Aug 19.
Hypertension is one of the most important risk factors of heart failure. In response to high blood pressure, the left ventricle manifests hypertrophic growth to ameliorate wall stress, which may progress into decompensation and trigger pathological cardiac remodeling. Despite the clinical importance, the temporal dynamics of pathological cardiac growth remain elusive. Here, we took advantage of the puromycin labeling approach to measure the relative rates of protein synthesis as a way to delineate the temporal regulation of cardiac hypertrophic growth. We first identified the optimal treatment conditions for puromycin in neonatal rat ventricular myocyte culture. We went on to demonstrate that myocyte growth reached its peak rate after 8-10 h of growth stimulation. At the in vivo level, with the use of an acute surgical model of pressure-overload stress, we observed the maximal growth rate to occur at after surgery. Moreover, RNA sequencing analysis supports that the most profound transcriptomic changes occur during the early phase of hypertrophic growth. Our results therefore suggest that cardiac myocytes mount an immediate growth response in reply to pressure overload followed by a gradual return to basal levels of protein synthesis, highlighting the temporal dynamics of pathological cardiac hypertrophic growth. We determined the optimal conditions of puromycin incorporation in cardiac myocyte culture. We took advantage of this approach to identify the growth dynamics of cardiac myocytes in vitro. We went further to discover the protein synthesis rate in vivo, which provides novel insights about cardiac temporal growth dynamics in response to pressure overload.
高血压是心力衰竭最重要的危险因素之一。为应对高血压，左心室表现出肥厚性生长以改善壁应力，这可能会发展为失代偿并引发病理性心脏重塑。尽管具有临床重要性，但病理性心脏生长的时间动态仍不清楚。在这里，我们利用嘌呤霉素标记方法来测量蛋白质合成的相对速率，以此来描述心脏肥厚性生长的时间调控。我们首先确定了嘌呤霉素在新生大鼠心室肌细胞培养中的最佳处理条件。接着我们证明，在生长刺激8 - 10小时后，心肌细胞生长达到峰值速率。在体内水平，通过使用压力超负荷应激的急性手术模型，我们观察到最大生长速率在手术后 出现。此外，RNA测序分析支持在肥厚性生长的早期阶段发生最深刻的转录组变化。因此，我们的结果表明，心肌细胞对压力超负荷会立即产生生长反应，随后蛋白质合成逐渐恢复到基础水平，突出了病理性心脏肥厚性生长的时间动态。我们确定了嘌呤霉素掺入心肌细胞培养的最佳条件。我们利用这种方法确定了体外心肌细胞的生长动态。我们进一步发现了体内的蛋白质合成速率，这为压力超负荷下心脏时间生长动态提供了新的见解。
