Equipe Transferts Ioniques et Rythmicité Cardiaque, Laboratoire Signalisation et Transports Ioniques Membranaires, CNRS ERL 7368, EA 7349, Université de Poitiers, France.
Service de chirurgie cardio-thoracique, CHU Poitiers, France.
FEBS J. 2018 Feb;285(3):518-530. doi: 10.1111/febs.14352. Epub 2017 Dec 29.
Recently, a new population of resident cardiac stem cells (CSCs) positive for the W8B2 marker has been identified. These CSCs are considered to be an ideal cellular source to repair myocardial damage after infarction. However, the electrophysiological profile of these cells has not been characterized yet. We first establish the conditions of isolation and expansion of W8B2 CSCs from human heart biopsies using a magnetic sorting system followed by flow cytometry cell sorting. These cells display a spindle-shaped morphology, are highly proliferative, and possess self-renewal capacity demonstrated by their ability to form colonies. Besides, W8B2 CSCs are positive for mesenchymal markers but negative for hematopoietic and endothelial ones. RT-qPCR and immunostaining experiments show that W8B2 CSCs express some early cardiac-specific transcription factors but lack the expression of cardiac-specific structural genes. Using patch clamp in the whole-cell configuration, we show for the first time the electrophysiological signature of BKCa current in these cells. Accordingly, RT-PCR and western blotting analysis confirmed the presence of BKCa at both mRNA and protein levels in W8B2 CSCs. Interestingly, BKCa channel inhibition by paxilline decreased cell proliferation in a concentration-dependent manner and halted cell cycle progression at the G0/G1 phase. The inhibition of BKCa also decreased the self-renewal capacity but did not affect migration of W8B2 CSCs. Taken together, our results are consistent with an important role of BKCa channels in cell cycle progression and self-renewal in human cardiac stem cells.
最近，人们发现了一种新的驻留心脏干细胞（CSC）群体，它们对 W8B2 标志物呈阳性。这些 CSC 被认为是修复梗塞后心肌损伤的理想细胞来源。然而，这些细胞的电生理特征尚未得到表征。我们首先使用磁分选系统和流式细胞分选，建立了从人心脏活检中分离和扩增 W8B2 CSC 的条件。这些细胞呈纺锤形形态，具有高度的增殖能力，并具有自我更新能力，能够形成集落。此外，W8B2 CSC 表达间充质标志物，但不表达造血和内皮标志物。RT-qPCR 和免疫染色实验表明，W8B2 CSC 表达一些早期心脏特异性转录因子，但缺乏心脏特异性结构基因的表达。通过全细胞膜片钳技术，我们首次在这些细胞中展示了 BKCa 电流的电生理特征。相应地，RT-PCR 和 Western blot 分析证实 W8B2 CSC 中存在 BKCa 在 mRNA 和蛋白水平上。有趣的是，BKCa 通道抑制剂 paxilline 以浓度依赖的方式抑制细胞增殖，并使细胞周期停滞在 G0/G1 期。BKCa 的抑制也降低了自我更新能力，但不影响 W8B2 CSC 的迁移。总之，我们的结果表明，BKCa 通道在人类心脏干细胞的细胞周期进展和自我更新中起着重要作用。
