Figure 4
L-type calcium current density is higher in iPSC-CMs from the DM1-1300 patient. (A) Representative L-type Ca2+ current traces recorded from CTRL, DM1-300, and DM1-1300 iPSC-CMs. The dashed line represents zero current (B) L-type Ca2+ channel current–voltage relationships recorded in CTRL (n = 20), DM1-300 (n = 10), and DM1-1300 (n = 17) iPSC-CMs. The current was normalized to the capacitance (pF) of the cells. (C) Dot plot showing the L-type Ca2+ channel current densities recorded at 10 mV. (D) Voltage-dependence of steady-state activation (n = 10–20) and inactivation (n = 7–9) of L-type channel Ca2+ currents. (E) RT-qPCR quantification of the expression of CaV1.2 mRNA in iPSC-CMs. Results are expressed relative to the expression of GATA4 mRNA. (F) Western blot for the quantification of CaV1.2 protein level in CTRL, DM1-300 and DM1-1300 iPSC-CMs. The membrane was cut in three sections and blot with the selected antibody. Panel 1 to 4 (from top to bottom) show CaV1.2, Na/K ATPase pump, GAPDH and total proteins (uncut blot, stain-free technology) signals, respectively. For each group, three samples from three independent differentiation were analyzed. The four panels came from the same gel/blot. Brightness and contrast were adjusted. No nonlinear adjustments were applied. (G) Quantification of CaV1.2 protein level in CTRL (n = 3), DM1-300 (n = 3) and DM1-1300 (n = 3) from western blot is shown in panel F. Results are expressed relative to total protein signal. Bars indicate SEM. **p < 0.01, ***p < 0.001 (CTRL vs DM1-1300) and ##p < 0.01, ###p < 0.001 (DM1-300 vs DM1-1300) as determined by ANOVA and Turkey’s post hoc test.
