Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, 126 University Place, Glasgow G12 8QQ, UK.
School of Mathematics and Statistics, University of Glasgow, Glasgow G12 8QQ, UK.
Int J Mol Sci. 2021 Jun 21;22(12):6621. doi: 10.3390/ijms22126621.
The immature electrophysiology of human-induced pluripotent stem cell-derived cardiomyocytes (hiCMs) complicates their use for therapeutic and pharmacological purposes. An insufficient inward rectifying current (I) and the presence of a funny current (if) cause spontaneous electrical activity. This study tests the hypothesis that the co-culturing of hiCMs with a human embryonic kidney (HEK) cell-line expressing the Kir2.1 channel (HEK-I) can generate an electrical syncytium with an adult-like cardiac electrophysiology. The mechanical activity of co-cultures using different HEK-I:hiCM ratios was compared with co-cultures using wildtype (HEK-WT:hiCM) or hiCM alone on days 3-8 after plating. Only ratios of 1:3 and 1:1 showed a significant reduction in spontaneous rate at days 4 and 6, suggesting that I was influencing the electrophysiology. Detailed analysis at day 4 revealed an increased incidence of quiescent wells or sub-areas. Electrical activity showed a decreased action potential duration (APD) at 20% and 50%, but not at 90%, alongside a reduced amplitude of the aggregate AP signal. A computational model of the 1:1 co-culture replicates the electrophysiological effects of HEK-WT. The addition of the I conductance reduced the spontaneous rate and APD20, 50 and 90, and minor variation in the intercellular conductance caused quiescence. In conclusion, a 1:1 co-culture HEK-I:hiCM caused changes in electrophysiology and spontaneous activity consistent with the integration of I into the electrical syncytium. However, the additional electrical effects of the HEK cell at 1:1 increased the possibility of electrical quiescence before sufficient I was integrated into the syncytium.
人诱导多能干细胞衍生的心肌细胞（hiCMs）的不成熟电生理学使其在治疗和药理学方面的应用变得复杂。内向整流电流（I）不足和有趣电流（if）的存在会导致自发性电活动。本研究测试了以下假设：将表达 Kir2.1 通道的人胚肾（HEK）细胞系与 hiCM 共培养可以产生具有成人样心脏电生理学的电合胞体。在接种后第 3-8 天，比较了不同 HEK-I：hiCM 比例的共培养物与野生型（HEK-WT：hiCM）或单独 hiCM 共培养物的机械活性。仅在第 4 天和第 6 天，1:3 和 1:1 的比例显示自发率显著降低，这表明 I 影响电生理学。第 4 天的详细分析显示，静止井或亚区的发生率增加。电活动显示动作电位持续时间（APD）在 20%和 50%处降低，但在 90%处没有降低，同时总 AP 信号幅度降低。1:1 共培养的计算模型复制了 HEK-WT 的电生理效应。添加 I 电导降低了自发率和 APD20、50 和 90，并且细胞间电导的微小变化导致静止。总之，1:1 的共培养 HEK-I：hiCM 导致电生理学和自发性活动的变化，这与 I 整合到电合胞体中一致。然而，在足够的 I 整合到合胞体之前，1:1 的 HEK 细胞的额外电效应增加了电静止的可能性。
