Ca2+-currents in human induced pluripotent stem cell-derived cardiomyocytes - effects of two different culture conditions

oleh: Ahmet Umur Uzun, Ahmet Umur Uzun, Ingra Mannhardt, Ingra Mannhardt, Kaja Breckwoldt, Kaja Breckwoldt, András Horváth, András Horváth, András Horváth, Silke Skytte Johannsen, Silke Skytte Johannsen, Arne Hansen, Arne Hansen, Thomas Eschenhagen, Thomas Eschenhagen, Torsten Christ, Torsten Christ

Format: Article
Diterbitkan: Frontiers Media S.A. 2016-09-01

Deskripsi

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) provide a unique opportunity to study human heart physiology and pharmacology and repair injured hearts. The suitability of hiPSC-CM critically depends on how closely they share physiological properties of human adult cardiomyocytes (CM). Here we investigated whether a 3D engineered heart tissue (EHT) culture format favors maturation and addressed the L-type Ca2+-current (ICa,L) as a readout. The results were compared with hiPSC-CM cultured in conventional monolayer (ML) and to our previous data from human adult atrial and ventricular CM obtained when identical patch-clamp protocols were used. HiPSC-CM were 2-3 fold smaller than adult CM, independently of culture format (capacitance ML 45±1 pF (n=289), EHT 45±1 pF (n=460), atrial CM 87±3 pF (n=196), ventricular CM 126±8 pF (n=50)). Only 88% of ML cells showed ICa, but all EHT. Basal ICa density was 10±1 pA/pF (n=207) for ML and 12±1 pA/pF (n=361) for EHT and was larger than in adult CM (7±1 pA/pF (p<0.05, n=196) for atrial CM and 6±1 pA/pF (p<0.05, n=47) for ventricular CM). However, ML and EHT showed robust T-type Ca2+-currents (ICa,T). While (-)-Bay K 8644, that activates ICa,L directly, increased ICa,L to the same extent in ML and EHT, β1- and β2-adrenoceptor effects were marginal in ML, but of same size as (-)-Bay K 8644 in EHT. The opposite was true for serotonin receptors. Sensitivity to β1 and β2-adrenoceptor stimulation was the same in EHT as in adult CM (-logEC50: 5.9 and 6.1 for norepinephrine (NE) and epinephrine (Epi), respectively), but very low concentrations of Rp-8-Br-cAMPS were sufficient to suppress effects (-logEC50: 5.3 and 5.3 respectively for NE and Epi). Taken together, hiPSC-CM express ICa,L at the same density as human adult CM, but, in contrast, possess robust ICa,T. Increased effects of catecholamines in EHT suggest more efficient maturation.