Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a cardiac channelopathy causing ventricular tachycardia following adrenergic stimulation. Pathogenic variants in RYR2-encoded ryanodine receptor 2 (RYR2) cause CPVT1 and cluster into domains I–IV, with the most N-terminal domain involving residues 77–466. Patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were generated for RYR2-F13L, -L14P, -R15P, and -R176Q variants. Isogenic control iPSCs were generated using CRISPR-Cas9/PiggyBac. Fluo-4 Ca2+ imaging assessed Ca2+ handling with/without isoproterenol (ISO), nadolol (Nad), and flecainide (Flec) treatment. CPVT1 iPSC-CMs displayed increased Ca2+ sparking and Ca2+ transient amplitude following ISO compared with control. Combined Nad treatment/ISO stimulation reduced Ca2+ amplitude and sparking in variant iPSC-CMs. Molecular dynamic simulations visualized the structural role of these variants. We provide the first functional evidence that these most proximal N-terminal localizing variants alter calcium handling similar to CPVT1. These variants are located at the N-terminal domain and the central domain interface and could destabilize the RYR2 channel promoting Ca2+ leak-triggered arrhythmias.
Original language | English (US) |
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Pages (from-to) | 2023-2036 |
Number of pages | 14 |
Journal | Stem Cell Reports |
Volume | 17 |
Issue number | 9 |
DOIs | |
State | Published - Sep 13 2022 |
Keywords
- calcium handling
- catecholaminergic polymorphic ventricular tachycardia
- induced pluripotent stem cell-derived cardiomyocytes
- ryanodine receptor
- sudden cardiac death
ASJC Scopus subject areas
- Biochemistry
- Genetics
- Developmental Biology
- Cell Biology