A new hERG allosteric modulator rescues genetic and drug-induced Long-QT Syndrome phenotypes in cardiomyocytes from isogenic pairs of patient induced pluripotent stem cells (2016)
Figure 2

Figure 2. LUF7346 enhances IKr in hiPSC-CMs.

A) Summary of the hPSC lines used in this study. WT, wild type healthy control; LQT1R594Q and JLNSR594Q, isogenic pair harbouring the heterozygous and the homozygous KCNQ1 c.1781G>A mutation, respectively; LQT2N996I and LQT2corr, isogenic pair in which the heterozygous c.2987A>T KCNH2 mutation is present or corrected, respectively; hESCWT and hESC-LQT2N996I, isogenic pair in which KCNH2 is wild type or the heterozygous c.2987A>T mutation was inserted, respectively; LQT1R190Q and LQT1corr, isogenic pair in which the heterozygous c.569G>A KCNQ1 mutation is present or corrected, respectively. Arrows indicates the parent line from which each genetically matched isogenic hiPSC were generated.

B) Baseline QT interval (top), baseline RR interval (middle), and baseline QT interval corrected with the Bazett's formula (bottom). Bar graphs are divided by isogenic pairs (LQT1R594Q and JLNSR594Q, left; LQT2corr, LQT2N996I, hESCWT, and hESC-LQT2N996I, middle; LQT1corr and LQT1R190Q, right) and in each graph the unrelated WT is shown as a comparison. N: 17-53. * = p<0.05. The colour of the symbol indicates comparisons and relative statistical significance.

C) Representative traces of IKr steady state activation in WT hiPSC-CMs in Tyrode (left), in the presence of 5 µM LUF7346 (middle) and after the application of 5 µM E4031 to selectively block IKr (right). Inset: voltage clamp protocol.

D) Average I/V relationships (left) and steady-state activation curves with superimposed Boltzmann’s fittings (right) under baseline conditions (black) and in the presence of 5 µM LUF7346 (red). * = p<0.05. N: 19.

E) Plot of the time constants (τ) of deactivation derived from biexponential fits (left) and representative examples (right) under baseline conditions (black) and in the presence of 3 µM LUF7346 (red). * = p<0.05. N: 17-21.

Data information: Kruskal-Wallis tests with pairwise Dunn's multiple testing correction. B: Adjusted p-values for QT: WT vs LQT1R594Q: 0.0029; WT vs JLNSR594Q: <0.0001; LQT1R594Q vs JLNSR594Q: <0.0001. WT vs LQT2corr: 0.0238; WT vs LQT2N996I: <0.0001; WT vs hESC-LQT2N996I: 0.0034; LQT2corr vs LQTN996I: 0.0151; LQT2N996I vs hESCWT: <0.0001; hESCWT vs hESC-LQT2N996I: 0.0367. WT vs LQT1corr: 0.0098; WT vs LQT1R190Q: <0.0001. LQT1corr vs LQT1R190Q: 0.0327. Adjusted p-values for RR: WT vs LQT1R594Q:<0.0001; WT vs JLNSR594Q: <0.0001. WT vs LQT2corr: 0.0001; WT vs LQT2N996I: 0.0031; WT vs hESCWT: <0.0001; WT vs hESC-LQT2N996I: <0.0001. WT vs LQT1corr: <0.0001; WT vs LQT1R190Q: 0.0012. Adjusted p-values for QTcB: WT vs JLNSR594Q: 0.0050; LQT1R594Q vs JLNSR594Q: <0.0001. WT vs LQT2N996I: 0.0074; LQT2corr vs LQT2N996I: 0.0084. LQT2N996I vs hESCWT <0.0001; LQT2N996I vs hESC-LQT2N996I: 0.0008. WT vs LQT1corr: 0.0303; WT vs LQT1R190Q: <0.0001. LQT1corr vs LQT1R190Q: 0.0018. D: Paired Two-ways ANOVA with Sidak’s multiple comparisons test. Adjusted p-values for I/V plot: -60 mV: 0.9780; -50 mV: >0.9999; -40 mV: >0.9999; -30: 0.0037; -20 mV: <0.0001; -10 mV: <0.0001; 0 mV: <0.0001; 10 mV: <0.0001; 20 mV: <0.0001; 30 mV: <0.0001. Adjusted p-values for activation: -50 mV: 0.9987; -40 mV: >0.9999; -30 mV: 0.4519; -20 mV: 0.0013; -10 mV: 0.8323; 0 mV: >0.9999; 10 mV: 0.9999; 20 mV: 0.5892. E: Unpaired Two-ways ANOVA with Sidak’s multiple comparisons test. Adjusted p-values for deactivation