Characterization of functional ion channels in human cardiac c-kit+ progenitor cells

Abstract

Cardiac progenitor cells play an important role in cardiac repair and regeneration; however, their cellular biology and electrophysiology are not understood. The present study characterizes the functional ion channels in human cardiac c-kit(+) progenitor cells using whole-cell patch voltage-clamp, RT-PCR, and Western blots. We found that several ionic currents were present in human cardiac c-kit(+) progenitor cells, including a large-conductance Ca(2+)-activated K(+) current (BKCa) in 86 % of cells, an inwardly rectifying K(+) current (I Kir) in 84 % of cells, a transient outward K(+) current (I to) in 47 % of cells, a voltage-gated tetrodotoxin-sensitive Na(+) current (I Na,TTX) in 61 % of cells. Molecular identities of these ionic currents were determined with RT-PCR and Western-blot analysis. KCa.1.1 (for BKCa), Kir2.1 (for I Kir), Kv4.2 and Kv4.3 (for I to), Nav1.3 and Nav1.6 (for I Na.TTX) were abundantly expressed in human cardiac c-kit(+) progenitor cells, which do not resemble cardiomyocytes at all. These results demonstrate for the first time that four types of ionic currents including BKCa, I to, I Kir, and I Na.TTX, are heterogeneously present in human cardiac c-kit(+) cells, which may be involved in regulating cellular physiology.

Functional BKCa channel in human resident cardiac stem cells expressing W8B2

“…Nevertheless, W8B2 + CSCs showed a low expression of CD90 and CD106 compared with data shown previously [1]. In stem cells, the presence of BKCa current has been reported in some cell types such as human embryonic stem cells [11], human MSCs of different origin [12][13][14], cancer stem cells [15] and human cardiac progenitor cells [16]. On the other hand, expression of CD106 can vary according to the tissue of origin in human mesenchymal stem cells (MSCs; 0.73% in adipose tissue MSCs, 7.44% in umbilical cord MSCs, 32.04% in bone marrow MSCs, and 65.01% in placenta MSCs) [10].…”

Bradykinin regulates cell growth and migration in cultured human cardiac c-Kit+ progenitor cells

“…The tissue collection was approved by the Ethics Committee of Hong Kong University with informed consent as described previously [28–30, 39]. The human cardiac c-Kit + progenitor cells (passages 3-8) were cultured at 37°C in 5% CO 2 in Alpha-modified Eagle's medium (α-MEM) containing 10% fetal bovine serum and 100 U/mL penicillin and 100 μg/mL streptomycin, and supplemented with 2 mM glutamine, 5 ng/ml epidermal growth factor (EGF), and 5 ng/mL basic fibroblast growth factor (bFGF).…”

“…The total RNA was extracted with TRIzol isolation system as described previously [39]. Reverse transcription (RT) was performed with the RT system (Takara Biotech, Dalian China) in a 20-μL reaction system.…”

“…This siRNA is target-specific 19- to 25-nt siRNA designed to knock down mRNA expression as previously described [29, 39]. Human cardiac c-Kit + cells at 60 - 80% confluence in 96-well plates or 6-well plates were transfected with siRNA molecules at 10-40 nM using Lipofectamine 2000 reagent (Invitrogen).…”

Cardiac progenitor cell ion currents: revealing a little more on the lesser known

“…Therefore, it is necessary to compare KCa3.1 functional expression in freshly isolated CPCs with cultured CPCs that are expanded for at least five passages. Patterns of ionic currents and phenotypes of ion channels are species dependent (Zhang et al . 2014).…”