Fig. 3: A cellular model of NAA10 dysfunction demonstrates repolarization abnormalities.
From: Dysregulation of N-terminal acetylation causes cardiac arrhythmia and cardiomyopathy
a Western blot analysis of whole-cell lysates from differentiated WT-, patient-derived (pNAA10R4S/Y)-, or genome-edited (eNAA10R4S/Y)-iPSC-CMs using NAA10, vinculin or cardiac troponin T antibodies. MW: molecular weight. b NAA10 protein levels, normalized to vinculin, were quantified: WT = 1.00 ± 0.04, pNAA10R4S/Y = 0.60 ± 0.06 (p < 0.0001), and eNAA10R4S/Y = 0.38 ± 0.06 (p < 0.0001); duplicates in 8 independent differentiation experiments; p < 0.0001; one-way ANOVA. c Differentiated iPSC-CMs were plated on multi-electrode arrays (MEAs, upper panel) and transduced with adenovirus for the channelrhodopsin ChR2-GFP (lower panel) for optical pacing. Scale bar: 750 μm d Representative MEA recordings of WT- (black), pNAA10R4S/Y- (red), and eNAA10R4S/Y- (blue) iPSC-CMs optically paced at 1 Hz with 488 nm light (blue triangles). Correspondingly colored dashed lines indicate field potential duration (FPD). e Quantified FPD paced at 1 Hz: WT = 156.9 ± 6.8 ms, pNAA10R4S/Y = 351.9 ± 8.1 ms (p < 0.0001), and eNAA10R4S/Y = 289.3 ± 4.6 ms (p < 0.0001); n = 22, 26, and 42, independent replicates; n = 6, 3, and 5, independent differentiation experiments; p < 0.0001; Kruskal-Wallis test. f Representative whole-cell recordings of single iPSC-CMs under current clamp conditions at 1 Hz pacing. g Action potential duration (APD) at 90% repolarization: WT = 290.1 ± 52.2 ms, pNAA10R4S/Y = 500.8 ± 35.9 ms (p = 0.0092), eNAA10R4S/Y = 464.8 ± 49.6 ms (p = 0.0282); n = 8, 11, and 12, independent experiments; n = 7, 6, and 7, independent differentiation experiments; p = 0.0128; one-way ANOVA. h The NAA10R4S variant did not affect peak action potential amplitude (APA) or mean diastolic potential (MDP): APA = 97.7 ± 3.9, 103.7 ± 3.8, 108.0 ± 2.9 mV; MDP = −67.0 ± 1.5, −64.0 ± 3.2, −62.7 ± 2.0 mV in WT-, pNAA10R4S/Y-, eNAA10R4S/Y-iPSC-CMs, respectively (p = 0.1538, 0.5086; one-way ANOVA). Sample sizes are annotated in each graph (same for panels g and h). Data are presented as mean ± SEM. ns = p > 0.1, *p < 0.05, **p < 0.01, ***p < 0.005, ****p < 0.0001. Source data are provided as a Source Data file.
