Department of Anatomy and Embryology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands.
Circulation. 2012 Jun 26;125(25):3079-91. doi: 10.1161/CIRCULATIONAHA.111.066092. Epub 2012 May 30.
Pluripotent stem cells (PSCs) offer a new paradigm for modeling genetic cardiac diseases, but it is unclear whether mouse and human PSCs can truly model both gain- and loss-of-function genetic disorders affecting the Na(+) current (I(Na)) because of the immaturity of the PSC-derived cardiomyocytes. To address this issue, we generated multiple PSC lines containing a Na(+) channel mutation causing a cardiac Na(+) channel overlap syndrome.
Induced PSC (iPSC) lines were generated from mice carrying the Scn5a(1798insD/+) (Scn5a-het) mutation. These mouse iPSCs, along with wild-type mouse iPSCs, were compared with the targeted mouse embryonic stem cell line used to generate the mutant mice and with the wild-type mouse embryonic stem cell line. Patch-clamp experiments showed that the Scn5a-het cardiomyocytes had a significant decrease in I(Na) density and a larger persistent I(Na) compared with Scn5a-wt cardiomyocytes. Action potential measurements showed a reduced upstroke velocity and longer action potential duration in Scn5a-het myocytes. These characteristics recapitulated findings from primary cardiomyocytes isolated directly from adult Scn5a-het mice. Finally, iPSCs were generated from a patient with the equivalent SCN5A(1795insD/+) mutation. Patch-clamp measurements on the derivative cardiomyocytes revealed changes similar to those in the mouse PSC-derived cardiomyocytes.
Here, we demonstrate that both embryonic stem cell- and iPSC-derived cardiomyocytes can recapitulate the characteristics of a combined gain- and loss-of-function Na(+) channel mutation and that the electrophysiological immaturity of PSC-derived cardiomyocytes does not preclude their use as an accurate model for cardiac Na(+) channel disease.
多能干细胞 (PSC) 为遗传心脏疾病的建模提供了新的范例，但由于 PSC 衍生的心肌细胞不成熟，尚不清楚小鼠和人类 PSC 是否真的可以模拟同时影响钠电流 (I(Na)) 的获得性功能和丧失性功能的遗传疾病。为了解决这个问题，我们生成了多个包含导致心脏钠离子通道重叠综合征的钠离子通道突变的 PSC 系。
从携带 Scn5a(1798insD/+) (Scn5a-het) 突变的小鼠中生成诱导多能干细胞 (iPSC) 系。这些小鼠 iPSC 与野生型小鼠 iPSC 进行了比较，同时还与用于生成突变小鼠的靶向小鼠胚胎干细胞系和野生型小鼠胚胎干细胞系进行了比较。膜片钳实验表明，与 Scn5a-wt 心肌细胞相比，Scn5a-het 心肌细胞的 I(Na) 密度显著降低，持续 I(Na) 增大。动作电位测量显示 Scn5a-het 心肌细胞的上升速度降低，动作电位时程延长。这些特征再现了直接从成年 Scn5a-het 小鼠分离的原代心肌细胞的发现。最后，从患有等效 SCN5A(1795insD/+) 突变的患者中生成了 iPSC。衍生的心肌细胞的膜片钳测量显示出与小鼠 PSC 衍生的心肌细胞相似的变化。
在这里，我们证明胚胎干细胞和 iPSC 衍生的心肌细胞都可以再现复合获得性功能和丧失性功能钠离子通道突变的特征，并且 PSC 衍生的心肌细胞的电生理不成熟并不排除它们作为心脏钠离子通道疾病的准确模型的使用。
