Premium
Intermediate‐conductance Ca 2+ ‐activated potassium and volume‐sensitive chloride channels in endothelial progenitor cells from rat bone marrow mononuclear cells
Author(s) -
Xu X.,
Xia J.,
Yang X.,
Huang X.,
Gao D.,
Zhou J.,
Lian J.,
Zhou J.
Publication year - 2012
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2011.02398.x
Subject(s) - peripheral blood mononuclear cell , progenitor cell , bone marrow , potassium , volume (thermodynamics) , conductance , chemistry , progenitor , microbiology and biotechnology , medicine , biology , stem cell , biochemistry , in vitro , organic chemistry , physics , mathematics , quantum mechanics , combinatorics
Aim Bone marrow endothelial progenitor cells ( BMEPC s) are believed to be a promising cell source for regenerative medicine; however, their electrophysiology properties have not been fully clarified, which is important to the clinical application of BMEPC s. The current study was designed to determine the transmembrane ion currents and mRNA expression levels of related ion channel subunits in rat BMEPC s. Methods Bone marrow mononuclear cells were isolated by density gradient separation and cultured in EPC medium. The transmembrane ion currents were determined using whole‐cell patch‐voltage clamp technique, and the levels of mRNA and protein expressions of functional ionic channels were measured using RT ‐ PCR and western immunoblot analysis. Results We observed two types of ionic currents in undifferentiated rat BMEPC s. One was Ca 2+ ‐activated potassium current ( I kca ), which was seen in approx. 90% of cells when 1 μ m Ca 2+ was employed in pipette solution, and it was predominantly inhibited by intermediate‐conductance I kca inhibitor clotrimazole. The other one was volume‐sensitive chloride current ( I cl ), which was detected in 85.7% of cells when BMEPC s were subjected to K + ‐free hypotonic extracellular solution, whose currents could be inhibited by 5‐nitro‐2‐(3‐phenylpropylamino) benzoic acid ( NPPB ). The corresponding ion channel genes and proteins, KCNN 4 for I kca and C lcn3 for I cl , were confirmed by RT ‐ PCR and western immunoblot analysis of BMEPC s. Conclusion Our results demonstrated for the first time that rat BMEPC s expressed intermediate‐conductance Ca 2+ ‐activated potassium currents and volume‐sensitive chloride currents, and corresponding genes and proteins of these two channels are KCNN 4 and C lcn3 respectively.