Characterization of ionic currents in human mesenchymal stem cells from bone marrow

Area of Science:

• Cellular Electrophysiology
• Stem Cell Biology
• Molecular Biology

Background:

• Mesenchymal stem cells (hMSCs) are crucial for regenerative medicine.
• Understanding their functional properties, like ion channel expression, is vital for therapeutic applications.
• Previous research has not fully elucidated the spectrum of functional ion channels in undifferentiated bone marrow hMSCs.

Purpose of the Study:

• To characterize the functional ion channels present in cultured undifferentiated human mesenchymal stem cells (hMSCs) derived from bone marrow.
• To identify the specific types of outward, sodium, and calcium currents and their corresponding molecular correlates.

Main Methods:

• Whole-cell patch clamp electrophysiology was employed to record ionic currents.
• Reverse transcription polymerase chain reaction (RT-PCR) was used to detect mRNA expression of ion channel subunits.
• Specific channel blockers (iberiotoxin, 4-aminopyridine, nifedipine) and toxins (tetrodotoxin) were utilized to identify current types.

Main Results:

• Three types of outward currents were identified: large conductance Ca(2+)-activated K(+) channel (I(KCa)), transient outward K(+) current (I(to)), and delayed rectifier K(+) current (IK(DR))-like.
• Tetrodotoxin-sensitive sodium current (I(Na.TTX)) was found in 29% of hMSCs, and nifedipine-sensitive L-type Ca(2+) current (I(Ca.L)) in 15%.
• RT-PCR confirmed the expression of corresponding mRNAs, including MaxiK, Kv4.2, Kv1.4, heag1, hNE-Na, and CACNAIC.

Conclusions:

• Undifferentiated bone marrow hMSCs express a diverse array of functional ion channels, including I(KCa), I(to), IK(DR)-like, I(Na.TTX), and I(Ca.L).
• These findings provide molecular and functional evidence for the presence of these ion channels in hMSCs.
• The characterized ion channel repertoire suggests potential roles in hMSC function and differentiation.