Institute of Physiology I, Medical Faculty, University of Bonn, 53127, Bonn, Germany.
Research Training Group 1873, University of Bonn, 53127, Bonn, Germany.
Nat Commun. 2019 Mar 20;10(1):1281. doi: 10.1038/s41467-019-09322-7.
The standard technique for investigating adrenergic effects on heart function is perfusion with pharmaceutical agonists, which does not provide high temporal or spatial precision. Herein we demonstrate that the light sensitive G-protein coupled receptor JellyOp enables optogenetic stimulation of G-signaling in cardiomyocytes and the whole heart. Illumination of transgenic embryonic stem cell-derived cardiomyocytes or of the right atrium of mice expressing JellyOp elevates cAMP levels and instantaneously accelerates spontaneous beating rates similar to pharmacological β-adrenergic stimulation. Light application to the dorsal left atrium instead leads to supraventricular extrabeats, indicating adverse effects of localized G-signaling. In isolated ventricular cardiomyocytes from JellyOp mice, we find increased Ca currents, fractional cell shortening and relaxation rates after illumination enabling the analysis of differential G-signaling with high temporal precision. Thus, JellyOp expression allows localized and time-restricted G stimulation and will provide mechanistic insights into different effects of site-specific, long-lasting and pulsatile G activation.
研究肾上腺素能对心脏功能影响的标准技术是用药物激动剂进行灌注，但这种方法不能提供高时间或空间精度。本文中，我们证明了光敏感 G 蛋白偶联受体 JellyOp 能够在心肌细胞和整个心脏中进行光遗传学刺激 G 信号转导。对表达 JellyOp 的转基因胚胎干细胞衍生的心肌细胞或右心房进行光照会升高 cAMP 水平，并立即加速自发搏动率，类似于药理学的β-肾上腺素能刺激。对表达 JellyOp 的小鼠的左心房背侧进行光照则会导致室上性早搏，表明局部 G 信号转导的不良影响。在 JellyOp 小鼠的分离心室心肌细胞中，我们发现光照后钙电流、细胞缩短分数和松弛率增加，从而能够以高时间精度分析不同的 G 信号转导。因此，JellyOp 的表达允许局部和时间限制的 G 刺激，并将为特定部位、持久和脉冲式 G 激活的不同作用提供机制见解。
