Cardiomyocyte Circadian Oscillations Are Cell-Autonomous, Amplified by β-Adrenergic Signaling, and Synchronized in Cardiac Ventricle Tissue.
Cardiomyocyte Circadian Oscillations Are Cell-Autonomous, Amplified by β-Adrenergic Signaling, and Synchronized in Cardiac Ventricle Tissue.
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DOI：
10.1371/journal.pone.0159618
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Welsh DK
中科院分区：
文献类型：
--
作者：
Beesley S;Noguchi T;Welsh DK
生物钟影响重要的心脏参数，如血压和心率，以及不良心脏事件，如心肌梗死和心源性猝死。在哺乳动物中，位于下丘脑视交叉上核的中央昼夜节律起搏器，控制心脏和全身许多其他组织中的细胞昼夜节律钟。心室外植体在培养中保持自主收缩和时钟基因表达的强大昼夜节律振荡。在本研究中，我们研究了内在心肌功能和昼夜节律之间的关系，在培养小鼠心脏。我们培养心室外植体或分散的心肌细胞表达PER 2：：LUC生物发光报告的昼夜节律钟基因表达的新生小鼠。我们发现异丙肾上腺素，一种已知可增加心率和收缩力的β-肾上腺素受体激动剂，也可放大心室外植体中的PER 2昼夜节律。我们在分散的心肌细胞中发现了强大的细胞自主PER 2昼夜节律。单细胞节律最初在心室外植体同步，但分散的细胞despersonized。此外，我们开发了一种方法，用于长期，同时监测时钟基因的表达，收缩率，和基础细胞内Ca 2+水平的心肌细胞使用PER 2：：LUC结合GCaMP 3，基因编码的荧光Ca 2+报告。与心肌细胞中强的PER 2昼夜节律相反，我们检测到收缩率没有节律，基础Ca 2+水平只有弱节律。总之，我们发现心肌细胞的PER 2昼夜节律是细胞自主的，由肾上腺素能信号放大，并通过心室外植体中的细胞间通讯同步，但我们没有检测到强大的收缩率或基础Ca 2+的昼夜节律。
Circadian clocks impact vital cardiac parameters such as blood pressure and heart rate, and adverse cardiac events such as myocardial infarction and sudden cardiac death. In mammals, the central circadian pacemaker, located in the suprachiasmatic nucleus of the hypothalamus, synchronizes cellular circadian clocks in the heart and many other tissues throughout the body. Cardiac ventricle explants maintain autonomous contractions and robust circadian oscillations of clock gene expression in culture. In the present study, we examined the relationship between intrinsic myocardial function and circadian rhythms in cultures from mouse heart. We cultured ventricular explants or dispersed cardiomyocytes from neonatal mice expressing a PER2::LUC bioluminescent reporter of circadian clock gene expression. We found that isoproterenol, a β-adrenoceptor agonist known to increase heart rate and contractility, also amplifies PER2 circadian rhythms in ventricular explants. We found robust, cell-autonomous PER2 circadian rhythms in dispersed cardiomyocytes. Single-cell rhythms were initially synchronized in ventricular explants but desynchronized in dispersed cells. In addition, we developed a method for long-term, simultaneous monitoring of clock gene expression, contraction rate, and basal intracellular Ca2+ level in cardiomyocytes using PER2::LUC in combination with GCaMP3, a genetically encoded fluorescent Ca2+ reporter. In contrast to robust PER2 circadian rhythms in cardiomyocytes, we detected no rhythms in contraction rate and only weak rhythms in basal Ca2+ level. In summary, we found that PER2 circadian rhythms of cardiomyocytes are cell-autonomous, amplified by adrenergic signaling, and synchronized by intercellular communication in ventricle explants, but we detected no robust circadian rhythms in contraction rate or basal Ca2+.