Basic/Translational Science -> Cell Physiology, Pharmacology, and Signaling D-PO02 - Poster Session II (ID 47) Poster

D-PO02-019 - Patient-independent Human Induced Pluripotent Stem Cell Model To Establish Cause Of Sudden Death In The Young (ID 983)

 C. Egly: Nothing relevant to disclose.


Background: Arrhythmias are a likely cause of sudden death in the young. Here we report a four-month-old male with sudden unexplained death. Molecular autopsy identified a novel heterozygous variant in the cardiac ryanodine receptor gene (RyR2-P2873S); gain of function mutations in RyR2 cause catecholaminergic polymorphic ventricular tachycardia (CPVT).
Objective: Since no patient cells were available, we performed gene-editing of human induced pluripotent stem cells (hiPSCs) from a normal volunteer to generate a patient-independent hiPSC model and study the pathogenicity of RyR2-P2873S.
Methods: CRISPR/Cas9 gene-editing generated hiPSC cardiomyocytes (CMs) heterozygous for RyR2-P2873S. Cellular function and RyR2 activity were assayed in 2D monolayers and single CMs and compared to isogenic control. A CPVT hiPSC model of a severe form of human CPVT (calsequestrin knockout) served as positive control.
Results: Analogous to CPVT hiPSCs, the RyR2-P2873S significantly increased spontaneous beating rate compared to isogenic control in 2D monolayers (2.46 Hz vs 1.26 Hz, p < 0.001 Fig. 1A). In single CMs, the RyR2-P2873S caused an even larger increase in calcium spark frequency than the positive CPVT control (p < 0.001, Fig 1B&C), indicating that the RyR2 gain of function induced by the novel RyR2 variant exceeds that of a severe form of CPVT.
Conclusion: RyR2-P2873S confers a cellular phenotype consistent with proarrhythmic liability and is likely the cause of sudden death. Patient-independent hiPSCs enable rapid screening and highlight the utility of hiPSC-CMs to study RyR2 variants for which no biological sample or family information is available.