RyR2-Mediated Ca2+ Leak Drives Progressive Arrhythmogenic Cardiomyopathy
- 1University of Wisconsin-Madison
Abstract
Background Abnormal sarcoplasmic reticulum (SR) Ca2+ release through ryanodine receptor 2 (RyR2) is a well-established mechanism of ventricular arrhythmias. Whether persistent RyR2 dysfunction can also initiate the structural remodeling characteristic of arrhythmogenic cardiomyopathy (ACM) remains unknown. We tested the hypothesis that chronic RyR2-mediated Ca2+ leak is sufficient to couple electrical instability to progressive cardiomyopathy. Methods We generated a rabbit carrying the severe gain-of-function RyR2-V2475F mutation and characterized disease progression using longitudinal cardiac phenotyping, continuous electrocardiographic monitoring, cellular electrophysiology and Ca2+ imaging, histopathology, biochemical analyses, and single-nucleus RNA sequencing (snRNA-seq). Therapeutic potential was evaluated by continuous treatment with the selective RyR2 inhibitor ent-verticilide for two months. Results RyR2-V2475F rabbits developed spontaneous ventricular tachyarrhythmias, sudden cardiac death, and progressive right ventricular (RV)-dominant fibrofatty cardiomyopathy recapitulating major features of human ACM. Malignant ventricular arrhythmias preceded overt structural remodeling and were associated at the cellular level with early spontaneous Ca2+ release and early afterdepolarizations. Early disease was characterized by remodeling of excitation-contraction coupling with preserved SR Ca2+ load and contractile function despite RyR2 dysfunction; upon disease progression, these compensatory changes were accompanied by SR Ca2+ depletion, impaired RV contractility and reduced left ventricular filling. Single-nucleus transcriptomics identified early fibroblast expansion and predicted cardiomyocyte-centered paracrine signaling before advanced fibrofatty infiltration. Cardiomyocytes also exhibited an altered lipid-metabolic transcriptome and intracellular lipid accumulation, accompanied by enhanced mitochondrial Ca2+ uptake. Selective RyR2 inhibition markedly reduced ventricular tachycardia burden and preserved RV contraction and LV filling during disease progression. Conclusions Severe RyR2 gain-of-function can lead to both malignant ventricular arrhythmias and progressive arrhythmogenic cardiomyopathy in a large-animal model, establishing persistent intracellular Ca2+ dysregulation as a mechanistic link between electrical and structural heart disease. The ability of selective RyR2 inhibition to suppress arrhythmias and preserve cardiac function identifies RyR2 as a potentially actionable therapeutic target in arrhythmogenic cardiomyopathy.
Related
- Elimination of Epicardial Late Potentials by Endocardial Ablation in Arrhythmogenic Right Ventricular Cardiomyopathy
- Incremental prognostic value of hepatic tissue alterations derived from cardiac magnetic resonance imaging for arrhythmogenic right ventricular cardiomyopathy: a case-control study
- Clinical relevance of lead-induced tricuspid regurgitation after transvenous implantable cardioverter-defibrillator implantation in arrhythmogenic cardiomyopathy
- Pathogenic variants in myoferlin (MYOF) cause arrhythmogenic cardiomyopathy
- Case Report: Suspected biventricular arrhythmogenic cardiomyopathy presenting as a dilated cardiomyopathy-like phenotype with multimodal phenotyping and cautious genetic interpretation
BibTeX
@misc{zheng2026ryr2mediated,
title = {{RyR2-Mediated Ca2+ Leak Drives Progressive Arrhythmogenic Cardiomyopathy}},
author = {J. Zheng and D. Ponce-Balbuena and S. Estrada and L. Xiao and E. B. Rios Perez and A. M. Gowda and C. E. Korcarz and K. M. Hansen and D. J. Blackwell and M. P. Thorpe and W. S. Akers and J. Wu and J. N. Johnston and A. M. Gomez and J.-P. Benitah and B. C. Knollmann and Y. E. Chen and H. H. Valdivia and F. J. Alvarado},
howpublished = {bioRxiv},
year = {2026},
month = nov,
doi = {10.64898/2026.11.02.763829},
url = {https://www.biorxiv.org/content/10.64898/2026.11.02.763829v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - RyR2-Mediated Ca2+ Leak Drives Progressive Arrhythmogenic Cardiomyopathy
AU - J. Zheng
AU - D. Ponce-Balbuena
AU - S. Estrada
AU - L. Xiao
AU - E. B. Rios Perez
AU - A. M. Gowda
AU - C. E. Korcarz
AU - K. M. Hansen
AU - D. J. Blackwell
AU - M. P. Thorpe
AU - W. S. Akers
AU - J. Wu
AU - J. N. Johnston
AU - A. M. Gomez
AU - J.-P. Benitah
AU - B. C. Knollmann
AU - Y. E. Chen
AU - H. H. Valdivia
AU - F. J. Alvarado
PY - 2026
DA - 2026/11/02
PB - bioRxiv
DO - 10.64898/2026.11.02.763829
UR - https://www.biorxiv.org/content/10.64898/2026.11.02.763829v1
AB - Background Abnormal sarcoplasmic reticulum (SR) Ca2+ release through ryanodine receptor 2 (RyR2) is a well-established mechanism of ventricular arrhythmias. Whether persistent RyR2 dysfunction can also initiate the structural remodeling characteristic of arrhythmogenic cardiomyopathy (ACM) remains unknown. We tested the hypothesis that chronic RyR2-mediated Ca2+ leak is sufficient to couple electrical instability to progressive cardiomyopathy. Methods We generated a rabbit carrying the severe gain-of-function RyR2-V2475F mutation and characterized disease progression using longitudinal cardiac phenotyping, continuous electrocardiographic monitoring, cellular electrophysiology and Ca2+ imaging, histopathology, biochemical analyses, and single-nucleus RNA sequencing (snRNA-seq). Therapeutic potential was evaluated by continuous treatment with the selective RyR2 inhibitor ent-verticilide for two months. Results RyR2-V2475F rabbits developed spontaneous ventricular tachyarrhythmias, sudden cardiac death, and progressive right ventricular (RV)-dominant fibrofatty cardiomyopathy recapitulating major features of human ACM. Malignant ventricular arrhythmias preceded overt structural remodeling and were associated at the cellular level with early spontaneous Ca2+ release and early afterdepolarizations. Early disease was characterized by remodeling of excitation-contraction coupling with preserved SR Ca2+ load and contractile function despite RyR2 dysfunction; upon disease progression, these compensatory changes were accompanied by SR Ca2+ depletion, impaired RV contractility and reduced left ventricular filling. Single-nucleus transcriptomics identified early fibroblast expansion and predicted cardiomyocyte-centered paracrine signaling before advanced fibrofatty infiltration. Cardiomyocytes also exhibited an altered lipid-metabolic transcriptome and intracellular lipid accumulation, accompanied by enhanced mitochondrial Ca2+ uptake. Selective RyR2 inhibition markedly reduced ventricular tachycardia burden and preserved RV contraction and LV filling during disease progression. Conclusions Severe RyR2 gain-of-function can lead to both malignant ventricular arrhythmias and progressive arrhythmogenic cardiomyopathy in a large-animal model, establishing persistent intracellular Ca2+ dysregulation as a mechanistic link between electrical and structural heart disease. The ability of selective RyR2 inhibition to suppress arrhythmias and preserve cardiac function identifies RyR2 as a potentially actionable therapeutic target in arrhythmogenic cardiomyopathy.
ER -