Ion Channel Expression and Characterization in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Figures

• 

  Figure 1. Effects of Iso and CCh as well as of acidosis on APs in hiPSC-CMs. (a) Representative spontaneous APs recorded before (Ctr) and after application of 10 μM Iso and 10 μM Iso + 30 μM CCh. (b) Representative spontaneous APs recorded before (Ctr) and after application of 30 μM CCh or extracellular solution with a pH value of 6.0. (c–h) APs were recorded at a fixed frequency of 1 Hz to analyze the changes of the AP parameters induced by Iso, CCh, and acidosis. Representative traces of APs (c), mean values of resting potential (d), AP amplitude (e), maximal depolarization speed (f), APD50 (g), and APD90 (h) are shown. Values given are mean ± SEM. n: number of cells. ∗ p < 0.05 versus Ctr.

• 

  Figure 2. Comparison of action potential parameters in cells from different subjects and after different differentiation times. Action potentials were measured in cells from the two healthy donors (D1 and D2) 30 to 40 days (30 d) and 50 to 60 days (60 d) after the onset of differentiation. (a) Mean values of resting potential (RP). (b) AP amplitude (APA). (c) Maximal depolarization speed (V max). (d) AP duration at 50% repolarization (APD50). (e) AP duration at 90% repolarization (APD90). Values given are mean ± SEM. n: number of cells. ns: p > 0.05.

• 

  Figure 3. Ion channel and receptor expression in hiPSC-CMs. Relative mRNA levels (normalized with GAPDH) of different ion channels and adrenoceptors as well as of muscarinic receptors were analyzed by qPCR in hiPSC-CMs. (a) Mean values of relative mRNA expression of ion channels and receptors in cells from donor 1 (D1) 30 to 40 days (days 30–40) and 50 to 60 day (days 50–60) after the onset of differentiation. (b) Mean values of relative mRNA expression of ion channels and receptors in cells from donor 2 (D2) 30 to 40 days (days 30–40) and 50 to 60 days (days 50–60) after the onset of differentiation. (c) Mean values of relative mRNA expression of ion channels in cells from donor 1 (D1) and donor 2 (D2) 30 to 40 days after the onset of differentiation. (d) Mean values of relative mRNA expression of ion channels in cells from donor 1 (D1) and donor 2 (D2) 50 to 60 days after the onset of differentiation. Results shown are mean ± SEM.

• 

  Figure 4. Ion channel currents in hiPSC-CMs. Whole currents were evoked by the indicated protocols, respectively. Specific blockers or solutions were applied to confirm the identity of expected currents. (a) Representative traces of TTX- (20 μM) sensitive peak INa. (b) Representative traces of nifedipine- (1 μM) sensitive ICa-L. (c) Representative traces of mibefradil- (10 μM) sensitive ICa-T. (d) Representative traces of ZD7288- (30 μM) sensitive If. (e) Representative traces of CCh- (10 μM) activated IKACh. (f) Representative traces of Ni2+- (5 mM) sensitive INCX. (g) Representative traces of 4-AP- (3 mM) sensitive Ito. (h) Representative traces of E-4031- (3 μM) sensitive IKr. (i) Representative traces of chromalol 293B- (10 μM) sensitive IKs. (j) Representative traces of Ba2+- (100 μM) sensitive IK1. (k) Representative traces of glibenclamide- (10 μM) sensitive IKATP. (l) Representative traces of pH- (6.0) sensitive potassium channel current. (m) Representative traces of apamin- (100 nM) sensitive ISK1–3. (n) Representative traces of NS8593- (10 μM) sensitive ISK1–3. (o) Representative traces of Na+- (50 mM) sensitive IKNa. (p) Representative traces of capsaicipine- (100 μM) sensitive…

• 

  Figure 5. Influences of ion channels on APs in hiPSC-CMs. APs were recorded at 1 Hz. Specific ion channel blockers or activators were applied to assess the contribution of an ion channel to AP. Percentage changes induced by drugs were calculated as (V drug − V control)/V control∗100, where V control is the value before the application of a drug and V drug is the value in the presence of a drug. (a) Percent (%) changes of resting potential (RP). (b) % changes of AP amplitude (APA). (c) % changes of maximal depolarization speed (V max). (d) % changes of APD at 50% repolarization (APD50). (e) % changes of APD at 90% repolarization (APD90). Values given are mean ± SEM. The number of cells (numbers in parentheses) is indicated in (b). ∗ p < 0.05 versus control.

• 

  Figure 6. Effects of Iso and CCh on ion channels in hiPSC-CMs. Different ion channel currents were recorded under different conditions. Iso (10 μM) or CCh (10 μM) was applied to check the effect on the recorded currents. (a) Mean values of inward currents in the absence and presence of Iso. (b) Mean values of outward currents in the absence and presence of Iso. (c) Mean values of inward currents in the absence and presence of CCh. (d) Mean values of outward currents in the absence and presence of CCh. Values given are mean ± SEM. The numbers in parentheses indicate the number of cells. ∗ p < 0.05 versus control.