Functional ion channels in mouse bone marrow mesenchymal stem cells.

Bone marrow mesenchymal stem cells (MSCs) are used as a cell source for cardiomyoplasty; however, the cellular electrophysiological properties are not fully understood. The present study was to investigate the functional ionic channels in undifferentiated mouse bone marrow MSCs using whole cell patch-voltage clamp technique, RT-PCR, and Western immunoblotting analysis. We found that three types of ionic currents were present in mouse MSCs, including a Ca(2+)-activated K(+) current (I(KCa)), an inwardly rectifying K(+) current (I(Kir)), and a chloride current (I(Cl)). I(Kir) was inhibited by Ba(2+), and I(KCa) was activated by the Ca(2+) ionophore A-23187 and inhibited by the intermediate-conductance I(KCa) channel blocker clotrimazole. I(Cl) was activated by hyposmotic (0.8 T) conditions and inhibited by the chloride channel blockers DIDS and NPPB. The corresponding ion channel genes and proteins, KCa3.1 for I(KCa), Kir2.1 for I(Kir), and Clcn3 for I(Cl), were confirmed by RT-PCR and Western immunoblotting analysis in mouse MSCs. These results demonstrate that three types of functional ion channel currents (i.e., I(Kir), I(KCa), and I(Cl)) are present in mouse bone marrow MSCs.