J Biomed Transl Res.  2017 Mar;18(1):7-12. 10.12729/jbtr.2017.18.1.007.

Passage-dependent expression of inward rectifying potassium current in human umbilical cord vein-derived mesenchymal stem cells

Affiliations
  • 1Division of Molecular and Life Sciences, Hanyang University, Ansan, 15588, Korea.
  • 2Department of Physiology, College of Medicine, Chungbuk National University, Cheongju, 28644, Korea. yangmik@chungbuk.ac.kr

Abstract

Although stem cells are used as important cell therapies in regenerative medicine, the electrophysiological problems that arise in the expansion of cells have not been known much. This study was conducted to investigate the functional expression of inward rectifying K⁺ current (IK(ir)) using a patch-clamp technique, and the change in the resting membrane potential and the membrane capacitance were investigated in mesenchymal stem cells derived from human umbilical vein (hUC-MSC). The IK(ir) plays an important role in regulating the resting membrane potential in many cells and is known to contribute to the maintenance of intracellular K⁺ concentration. In this study, electrophysiologically recorded current exhibited typical IK(ir) characteristics. The current shifted along the K⁺ equilibrium potential (E(k)) with the extracellular K⁺ concentration change. In addition, IK(ir) was blocked by the divalent Ba²âº in a dose-dependent manner. The frequency of functional expression of IK(ir) changed with number of passages (P2: 5.3% vs P8: 77.8% vs P12: 34.5%). There was no significant change in the resting membrane potential of hUC-MSC (P2: -21.0 mV, P8: -20.1 mV and P12: -21.9 mV). However, the capacitance of the cell membrane was significantly changed after P9 (P2: 8.9 pF vs P9: 16.9 pF) compared to P2. All the results suggest that changes in electrophysiological distribution of IK(ir) as the passages increase may cause changes in K⁺ permeability even in cell proliferation and differentiation, suggesting a possible physiological role in maintaining cell homeostasis and resting membrane potential (RMP).

Keyword

mesenchymal stem cells; inward rectifying K current (IK(ir)); umbilical cord vein; passage; capacitance

MeSH Terms

Cell Membrane
Cell Proliferation
Homeostasis
Humans*
Membrane Potentials
Membranes
Mesenchymal Stromal Cells*
Patch-Clamp Techniques
Permeability
Potassium*
Regenerative Medicine
Stem Cells
Umbilical Cord*
Umbilical Veins
Potassium
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