Cardiomyocytes with the CRISPR-edited S4938F-RyR2 mutation exhibited smaller L-type Ca2+ currents but larger SR Ca2+ content and more frequent spontaneous Ca2+ sparks compared to wild type cells.
Does the S4938F-RyR2 mutation alter Ca2+ signaling and electrophysiological properties in human iPSC-derived cardiomyocytes?
The S4938F-RyR2 mutation alters calcium handling in human cardiomyocytes, increasing SR calcium content and spontaneous calcium sparks, which may underlie its arrhythmogenic phenotype.
Type-2 ryanodine receptor (RyR2) is the major Ca2+ release channel of the cardiac sarcoplasmic reticulum (SR) that controls the rhythm and strength of the heartbeat, but its malfunction may generate severe arrhythmia leading to sudden cardiac death or heart failure. S4938F-RyR2 mutation in the carboxyl-terminal was expressed in human induced pluripotent stem cells derived cardiomyocytes (hiPSC-CMs) using CRISPR/Cas9 gene-editing technique. Ca2+ signaling and electrophysiological properties of beating cardiomyocytes carrying the mutation were studied using total internal reflection fluorescence microscopy (TIRF) and patch clamp technique. In mutant cells, L-type Ca2+ currents (ICa), measured either by depolarizations to zero mV or repolarizations from +100 mV to –50 mV, and their activated Ca2+ transients were significantly smaller, despite their larger caffeine-triggered Ca2+ release signals compared to wild type (WT) cells, suggesting ICa-induced Ca2+ release (CICR) was compromised. The larger SR Ca2+ content of S4938F-RyR2 cells may underlie the higher frequency of spontaneously occurring Ca2+ sparks and Ca2+ transients and their arrhythmogenic phenotype.
Tóth et al. (Wed,) conducted a other in RyR2-S4938F mutation / Arrhythmia. S4938F-RyR2 mutation via CRISPR/Cas9 vs. Wild type (WT) cells was evaluated on Ca2+ signaling and electrophysiological properties. Cardiomyocytes with the CRISPR-edited S4938F-RyR2 mutation exhibited smaller L-type Ca2+ currents but larger SR Ca2+ content and more frequent spontaneous Ca2+ sparks compared to wild type cells.