Impact of the Gβ5-S81L variant on IK,ACh in RA-treated hiPSC-CMs. (A,B) Typical recordings (A) and average IK,ACh density (B) in WT, S81Lhet and S81Lhomo hiPSC-CMs. Average IK,ACh density is increased in S81Lhomo hiPSC-CMs compared to WT and S81Lhet hiPSC-CMs. *P<0.05 (Kruskal–Wallis non-parametric test, followed by Bonferroni post-hoc analysis). (C,D) Time constant (τ) of IK,ACh activation (C) and deactivation (D). (B-D) WT, n=27; S81Lhet, n=11; S81Lhomo, n=20 hiPSC-CMs. (E) Percentage of desensitization, measured as the percentage of IK,ACh decrease at steady state upon continuous CCh application; WT, n=3; S81Lhet, n=6; S81Lhomo, n=5 hiPSC-CMs. (F) Transcript level of the genes involved in G-protein-coupled activation of IK,ACh. Data are mean±s.e.m. of three biological differentiation replicas and expression level of each gene in S81Lhet and S81Lhomo hiPSC-CMs is indicated as relative to its expression in WT hiPSC-CMs. No significant differences are observed in KCNJ3, KCNJ5, RGS6 and GNB5 transcript abundance across the WT, S81Lhet and S81Lhomo hiPSC-CMs.
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