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Ryanodine receptor-mediated calcium leak drives progressive development of an atrial fibrillation substrate in a transgenic mouse model
- Publication Year :
- 2014
-
Abstract
- Background— The progression of atrial fibrillation (AF) from paroxysmal to persistent forms remains a major clinical challenge. Abnormal sarcoplasmic reticulum (SR) Ca 2+ leak via the ryanodine receptor type 2 (RyR2) has been observed as a source of ectopic activity in various AF models. However, its potential role in progression to long-lasting spontaneous AF (sAF) has never been tested. This study was designed to test the hypothesis that enhanced RyR2-mediated Ca 2+ release underlies the development of a substrate for sAF and to elucidate the underlying mechanisms. Methods and Results— CREM-IbΔC-X transgenic (CREM) mice developed age-dependent progression from spontaneous atrial ectopy to paroxysmal and eventually long-lasting AF. The development of sAF in CREM mice was preceded by enhanced diastolic Ca 2+ release, atrial enlargement, and marked conduction abnormalities. Genetic inhibition of Ca 2+ /calmodulin-dependent protein kinase II–mediated RyR2-S2814 phosphorylation in CREM mice normalized open probability of RyR2 channels and SR Ca 2+ release, delayed the development of spontaneous atrial ectopy, fully prevented sAF, suppressed atrial dilation, and forestalled atrial conduction abnormalities. Hyperactive RyR2 channels directly stimulated the Ca 2+ -dependent hypertrophic pathway nuclear factor of activated T cell/Rcan1-4, suggesting a role for the nuclear factor of activated T cell/Rcan1-4 system in the development of a substrate for long-lasting AF in CREM mice. Conclusions— RyR2-mediated SR Ca 2+ leak directly underlies the development of a substrate for sAF in CREM mice, the first demonstration of a molecular mechanism underlying AF progression and sAF substrate development in an experimental model. Our work demonstrates that the role of abnormal diastolic Ca 2+ release in AF may not be restricted to the generation of atrial ectopy but extends to the development of atrial remodeling underlying the AF substrate.
- Subjects :
- Genetically modified mouse
Male
medicine.medical_specialty
Atrial enlargement
Transgene
Medizin
Mice, Transgenic
Ryanodine receptor 2
Article
Mice
Heart Conduction System
Physiology (medical)
Internal medicine
Atrial Fibrillation
Medicine
Animals
Myocytes, Cardiac
Protein kinase A
business.industry
Ryanodine receptor
Endoplasmic reticulum
Age Factors
Atrial fibrillation
Ryanodine Receptor Calcium Release Channel
medicine.disease
Mice, Inbred C57BL
Disease Models, Animal
Sarcoplasmic Reticulum
Endocrinology
Disease Progression
Calcium
Female
medicine.symptom
Cardiology and Cardiovascular Medicine
business
Calcium-Calmodulin-Dependent Protein Kinase Type 2
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....6659a9ae3573f27e324ba64703cf376f