Fig. 3: Activated ROS-CAMKII-RYR2 pathway links down-regulated SIRT1 and arrhythmic phenotype in A388fs iPSC-CMs.

a, b Western blot analysis of total CaMKII, p-CaMKII (CaMKII-T286), total RYR2, and p-RYR2 (RYR2−2814S) expression in Con−1, II-1-corr, and II-1 iPSC-CMs. n = 4 independently biological repeats. c, d Western blot analysis of protein expression of total CaMKII and oxidized CaMKII (M281-M282 oxidation; ox-CaMKII) in Con-1, II-1-corr, and II-1 iPSC-CMs. n = 4 independently biological repeats. e, f Western blot analysis of total CaMKII, p-CaMKII, total RYR2, and p-RYR2 expression in II-1 iPSC-CMs treated with DMSO, SRT, or MT, respectively. n = 4 independently biological repeats. g, h Western blot analysis of protein expression of total and oxidized CaMKII in II-1 iPSC-CMs treated with DMSO, SRT or mitoTEMPO (MT). n = 4 independently biological repeats. i Representative Ca²⁺ transient traces recorded from II-1 iPSC-CMs treated with DMSO, SRT, MT or KN93, respectively. j, k Violin graphs to compare the Ca²⁺ transient amplitude and diastolic [Ca²⁺]_i among different groups in i. n = 37 (II-1 + KN93), 74 (II-1 + SRT), 76 (II-1 + MT), 80 (II-1 + DMSO) cells. l Representative traces of cytosolic Ca²⁺ fluorescence in II-1 iPSC-CMs treated with DMSO, SRT, MT, or KN93 in NT solution and exposed to 0 Na⁺, 0 Ca²⁺ solution containing tetracaine (Tet) and caffeine (Caff). m–n Violin graphs to compare the RYR2-mediated SR Ca²⁺ leak and SR Ca²⁺ load among different groups in l. n = 49 (II-1 + DMSO), 54 (II-1 + KN93), 55 (II-1 + SRT), and 58 (II-1 + MT) cells. o Representative electrophysiological measurements of spontaneous action potentials in II-1 iPSC-CMs treated with DMSO, resveratrol (resver), SRT, NAC, MT, or KN93, respectively. p Bar graph to compare the occurrence of arrhythmias among different groups in o. Data are presented as mean ± SEM in b, d, f, h. p values were calculated by Dunnett’s multiple comparisons test in b, d, f, h, j, k, m, n. Source data are provided as a Source Data file.