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Characterization of ion currents of murine CD 117 pos stem cells in vitro and their modulation under AT 2 R stimulation
Author(s) -
Ludwig M.,
Skorska A.,
Tölk A.,
Hopp H.H.,
Patejdl R.,
Li J.,
Steinhoff G.,
Noack T.
Publication year - 2013
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/apha.12115
Subject(s) - hyperpolarization (physics) , stem cell , chemistry , patch clamp , membrane potential , pacemaker potential , microbiology and biotechnology , losartan , stimulation , ion channel , receptor , biophysics , angiotensin ii , biology , endocrinology , biochemistry , organic chemistry , nuclear magnetic resonance spectroscopy
Aim Hematopoietic stem cells, especially CD 117 pos cells, have been found to possess a regenerative potential in various tissues, in particular cardiac muscle. However, the characterization of the relevant ion currents of stem cells prior to implantation lacks documentation. Activation of angiotensin II type 2 receptor ( AT 2 R) can lead to further cell differentiation and receptor auto‐expression and might thus influence electrophysiological properties of CD 117 pos stem cells. This study was designed to functionally characterize membrane currents of CD 117 pos cells under normal and AT 2 R‐stimulated conditions. Methods CD 117 pos murine bone marrow stem cells were isolated with MACS technique and stimulated for the AT 2 R with angiotensin II and losartan for 3–5 days prior to patch‐clamp measurements. RT ‐ PCR was used to determine channel expression. Endothelial properties were analysed with immunocytochemistry and ac LDL uptake assay. Results A well‐expressed inward rectifying current ( I Kir ) was identified in cultured CD 117 pos cells. Furthermore, a ZD 7288 ( HCN channel blocker)‐sensitive current component was isolated. Voltage‐dependent potassium currents and chloride currents were less expressed. A small fraction of cells demonstrated voltage‐ and time‐dependent inward currents. In AT 2 R‐stimulated cells inward rectifying the hyperpolarization‐induced inward currents were slightly attenuated on the translational level but showed increased mRNA expression. Cultured CD 117 pos cells express CD 31 and VEGFR ‐2 and significantly increased the uptake of ac LDL . Conclusions CD 117 pos cells do not have properties of action potential–generating cells and moderately change their excitability during AT 2 R stimulation. Electrophysiological and molecular properties of control and AT 2 R‐stimulated cells point to a differentiation to vascular endothelial cells. This could increase beneficial vascularization in injured tissues.