Weiser-Bitoun Ido, Mazgaoker Savyon, Eid Rami, Brosh Inbar, Yaniv Yael
Laboratory of Bioelectric and Bioenergetic Systems, Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3525433, Israel.
iScience. 2025 Feb 12;28(3):112005. doi: 10.1016/j.isci.2025.112005. eCollection 2025 Mar 21.
Protein kinase A (PKA) phosphorylates proteins crucial for rhythm modulation, with its dysregulation linked to arrhythmias. This study investigated PKA activity's spatiotemporal dynamics in spontaneously beating cardiac organoids. We hypothesized that PKA activity would respond to autonomic stimulation and exhibit spatial heterogeneity upon drug-induced modulation. Forskolin (activator) and H-89 (inhibitor) altered PKA activity ratios from 1 to 1.52 ± 0.03 and 0.89 ± 0.03, respectively. Hill equation-based regression showed a high fit of PKA activity behavior for all four tested drugs (forskolin, H-89, isoproterenol, or carbachol) at concentrations. Responses to forskolin or isoproterenol, which increase PKA activity, showed higher heterogeneity (10.1 ± 0.8% or 8.7 ± 1%) compared to responses to H-89 or carbachol (4.3 ± 0.8% or 4.4 ± 1.2%), which decrease PKA activity. These results reveal the intricate spatial dynamics of PKA activity in cardiac organoids and its dependence on PKA activation levels.
蛋白激酶A（PKA）使对节律调节至关重要的蛋白质磷酸化，其失调与心律失常有关。本研究调查了自发性搏动心脏类器官中PKA活性的时空动态。我们假设PKA活性会对自主神经刺激作出反应，并在药物诱导调节时表现出空间异质性。福斯高林（激活剂）和H-89（抑制剂）分别将PKA活性比率从1改变为1.52±0.03和0.89±0.03。基于希尔方程的回归显示，在各浓度下，所有四种测试药物（福斯高林、H-89、异丙肾上腺素或卡巴胆碱）的PKA活性行为拟合度都很高。与降低PKA活性的H-89或卡巴胆碱（4.3±0.8%或4.4±1.2%）相比，对增加PKA活性的福斯高林或异丙肾上腺素的反应表现出更高的异质性（10.1±0.8%或8.7±1%）。这些结果揭示了心脏类器官中PKA活性复杂的空间动态及其对PKA激活水平的依赖性。
