Background: Endothelial cells derived from human induced pluripotent stem cells (hiPSC-ECs) provide a new opportunity for researches on vascular functions and serve as a model to study the mechanism of cardiovascular disease. However, the ion channel expression and functions as well as regulations in hiPSC-ECs still need to be fully characterized. Therefore, the objective of this study was to investigate the similarity and differences between hiPSC-ECs and primary Human Cardiac Microvascular Endothelial Cells (HCMECs) isolated from heart ventricles.

Methods: Endothelial cells were derived from hiPS cells that were generated from human skin fibroblasts of three healthy donors. HCMECs were obtained from PromoCell (C-12285, PromoCell GmbH, Heidelberg, Germany).  Flow cytometry and Fluorescence-activated cell sorting (FACS), immunofluorescence staining, quantitative polymerase chain reaction(qPCR), enzyme-linked immunosorbent assay (Elisa) and patch clamp techniques were employed for the study.

Results: HiPSC-ECs were successfully generated and were identified by endothelial markers. The mRNA expression of ion channels KCNN2, KCNN4, KCNMA1, TRPV2, and SLC8A1 in hiPSC-ECs was significantly higher in hiPSC-ECs compared with HCMECS. AT1 receptor mRNA expression in hiPSC-ECs was higher than HCMECS. AT2 receptor mRNA expression was the highest of all receptors. ADRB1, ADRB2, GNA11, and Gai m RNA expression in hiPSC-ECs were significantly higher than HCMECs. CHRM3, DRD2, DRD3, and DRD4 in hiPSC-ECs were significantly lower than HCMECS. The functional characteristics of endothelial cells, such as tube formation, LDL uptake, are not statistically different between hiPSC-ECs and HCMECs. Phenylephrine (PE) increased similarly the release of the endogenous vasoconstrictor endothelin-1 (ET-1) in hiPSC-ECs and HCMECs. Acetylcholine significantly increased nitric oxide-synthase content in hiPSC-ECs and HCMECs. The membrane potential and calcium-activated potassium channel currents (I_SK1-3 and I_SK4) were similar in hiPSC-ECs and HCMECs. The inward rectifier potassium channel current (I_K1) in hiPSC-ECs was significantly larger than that in HCMECs. while the ATP-sensitive potassium channel current (I_KATP) in hiPSC-ECs was smaller than that of HCMECs. We also noted a higher expression in exosomes marker CD81 in hiPSC-ECs and a higher expression of CD9 and CD63 in HCMECs.

Conclusion：Our study demonstrated that hiPSC-ECs possess both similarity and differences comparing native endothelial cells, which may provide useful information for researches using hiPSC-ECs on endothelial functions and diseases.