Functional Expression of Ion Channels in Mesenchymal Stem Cells Derived from Umbilical Cord Vein

¹ Division of Molecular and Life Science, Hanyang University, Ansan, Korea
² Department of Neurology, Hanyang University Hospital, Seoul, Korea
³ Bioengineering Institute, CoreStem Inc., Seoul, Korea
⁴ Department of Physiology, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Korea

^* To whom correspondence should be addressed. E-mail: ygchai{at}hanyang.ac.kr.

	Abstract

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 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 RT-PCR. Three types of outward current were found in these cells: the Ca²⁺-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 TEA, and IK_Ca was sensitive to a specific blocker, iberiotoxin. I_to was inhibited by 4-AP. Another type of inward rectifier K⁺ current (K_ir) was also detected in about five percent 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 (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.