Abstract
Abstract 12295: Characterization of a Novel Homozygous Multi-exon Ryr2 Duplication Associated With Exertion-related Sudden Unexplained Death in the Young in the Amish Community Using Patient-specific Hipsc-cardiomyocytes
Circulation (New York, N.Y.), Vol.140(Suppl_1 Suppl 1), pp.A12295-A12295
11/19/2019
DOI: 10.1161/circ.140.suppl_1.12295
Abstract
BackgroundWe identified a novel homozygous duplication involving the promoter region and exons 1-4 of RYR2 that is responsible for highly penetrant, exertion-related sudden deaths in the young (SUDY) and sudden cardiac arrests (SCA) in the Amish community without an overt phenotype to suggest RYR2-mediated CPVT. Here, we characterize patient-derived induced pluripotent stem cell--cardiomyocytes (iPSC-CMs) from two unrelated patients.MethodsHomozygous RYR2-duplication (RYR2-DUP) iPSC lines were generated from two unrelated patients (12-year-old female and a 10-year-old male) with exertional SCA. Two unrelated wild-type (WT) control iPSC lines were analyzed also. Conventional cardiac differentiation methods were used to generate iPSC-CMs. Calcium handling under baseline, 10mM caffeine, and 100nM isoproterenol conditions was assessed by live cell imaging with a Fluo-4 calcium indicator. qRT-PCR, western blot, and immunostaining were used to assess RYR2 gene/RyR2 protein expression. Arrhythmic activity was assessed using an xCELLigence RTCA CardioECR instrument.ResultsThere was no difference in baseline Ca handling (Ca transient amplitude, time-to-peak, or decay time) measurements between WT- and the RYR2-DUP-iPSC-CMs patient lines. However, compared to WT-iPSC-CMs, both patient lines demonstrated a dramatic reduction in caffeine and isoproterenol stimulated Ca transient amplitude, suggesting RYR2 loss-of-function. There was a >50% reduction in RYR2 transcript/RyR2 protein expression in both patient iPSC-CMs compared to WT. Delayed afterdepolarization-like ectopy was observed in the RYR2-DUP-iPSC-CMs but not in the WT-iPSC-CMs.ConclusionHere, we characterized the first iPSC-CM model of a homozygous multi-exon RYR2 duplication mutation identified in two large Amish pedigrees associated with exertion-related SUDY/SCA. Unlike the typical gain-of-function mechanism observed in RYR2-mediated CPVT, the homozygous multi-exon duplication precipitates a loss-of-function in calcium handling, presumably through RYR2 haploinsufficiency.
Details
- Title: Subtitle
- Abstract 12295: Characterization of a Novel Homozygous Multi-exon Ryr2 Duplication Associated With Exertion-related Sudden Unexplained Death in the Young in the Amish Community Using Patient-specific Hipsc-cardiomyocytes
- Creators
- David Tester - Mayo ClinicC S Kim - Mayo ClinicSamantha Hamrick - Mayo ClinicHannah Bombei - University of IowaKristi Fitzgerald - DuPontCarla Haglund-Turnquist - Mayo ClinicDianne Atkins - University of IowaLuis Ochoa - University of IowaIan Law - University of IowaJoel Temple - DuPontMichael Ackerman - Mayo Clinic
- Resource Type
- Abstract
- Publication Details
- Circulation (New York, N.Y.), Vol.140(Suppl_1 Suppl 1), pp.A12295-A12295
- Publisher
- by the American College of Cardiology Foundation and the American Heart Association, Inc
- DOI
- 10.1161/circ.140.suppl_1.12295
- ISSN
- 0009-7322
- eISSN
- 1524-4539
- Language
- English
- Date published
- 11/19/2019
- Academic Unit
- Stead Family Department of Pediatrics; Cardiology
- Record Identifier
- 9984354506702771
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