Park Kyoung Sun, Jung Kyoung Hwa, Kim Seung Hyun, Kim Kyung Suk, Choi Mi Ran, Kim Yangmi, Chai Young Gyu
Division of Molecular and Life Science, Hanyang University, Ansan, Korea.
Stem Cells. 2007 Aug;25(8):2044-52. doi: 10.1634/stemcells.2006-0735. Epub 2007 May 24.
Mesenchymal stem cells have the ability to renew and differentiate into various lineages of mesenchymal tissues. We used undifferentiated human mesenchymal-like stem cells from human umbilical cord vein (hUC-MSCs), a cell line which contains several mesenchymal cell markers. We characterized functional ion channels in cultured hUC-MSCs with whole-cell patch clamp and reverse transcription-polymerase chain reaction (RT-PCR). Three types of outward current were found in these cells: the Ca(2+)-activated K(+) channel (IK(Ca)), a transient outward K(+) current (I(to)), and a delayed rectifier K(+) current (IK(DR)). IK(Ca) and IK(DR) were totally suppressed by tetraethylammonium, and IK(Ca) was sensitive to a specific blocker, iberiotoxin. I(to) was inhibited by 4-aminopyridine. Another type of inward rectifier K(+) current (K(ir)) was also detected in approximately 5% of hUC-MSCs. Elevation of external potassium ion concentration increased the K(ir) current amplitude and positively shifted its reversal potential. In addition, inward Na(+) current (I(Na)) was found in these cells ( approximately 30%); the current was blocked by tetrodotoxin and verapamil. In the RT-PCR analysis, Kv1.1, Kv4.2, Kv1.4, Kir2.1, heag1, MaxiK, hNE-Na, and TWIK-1 were detected. These results suggested that multiple functional ion channel currents, IK(Ca), IK(DR), I(to), I(Na), and K(ir), are expressed in hUC-MSCs. Disclosure of potential conflicts of interest is found at the end of this article.
间充质干细胞具有更新能力，并能分化为间充质组织的各种谱系。我们使用了来自人脐带静脉的未分化人源间充质样干细胞（hUC-MSCs），该细胞系含有多种间充质细胞标志物。我们用全细胞膜片钳和逆转录-聚合酶链反应（RT-PCR）对培养的hUC-MSCs中的功能性离子通道进行了表征。在这些细胞中发现了三种外向电流：钙激活钾通道（IK(Ca)）、瞬时外向钾电流（I(to)）和延迟整流钾电流（IK(DR)）。IK(Ca)和IK(DR)被四乙铵完全抑制，IK(Ca)对特异性阻断剂iberiotoxin敏感。I(to)被4-氨基吡啶抑制。在大约5%的hUC-MSCs中还检测到另一种内向整流钾电流（K(ir)）。细胞外钾离子浓度升高增加了K(ir)电流幅度并使其逆转电位正向移动。此外，在这些细胞中发现了内向钠电流（I(Na)）（约30%）；该电流被河豚毒素和维拉帕米阻断。在RT-PCR分析中，检测到了Kv1.1、Kv4.2、Kv1.4、Kir2.1、heag1、MaxiK、hNE-Na和TWIK-1。这些结果表明，hUC-MSCs中表达了多种功能性离子通道电流，即IK(Ca)、IK(DR)、I(to)、I(Na)和K(ir)。潜在利益冲突的披露见本文末尾。
