Sudden death in familial polymorphic ventricular tachycardia associated with calcium release channel (ryanodine receptor) leak
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View abstract on PubMed
Summary
This summary is machine-generated.Familial polymorphic ventricular tachycardia (FPVT) is linked to RyR2 mutations causing exercise-induced arrhythmias. The drug JTV519 normalized RyR2 channel function, offering a potential treatment for sudden cardiac death.
Area Of Science
- Cardiovascular Genetics
- Molecular Cardiology
- Ion Channel Physiology
Background
- Familial polymorphic ventricular tachycardia (FPVT) is associated with exercise-induced arrhythmias and sudden cardiac death.
- These events stem from missense mutations in the cardiac ryanodine receptor (RyR2), a critical Ca2+ release channel for heart excitation-contraction coupling.
Purpose Of The Study
- To investigate the functional consequences of specific RyR2 mutations linked to FPVT.
- To explore the potential therapeutic effects of JTV519 on RyR2 channel function in the context of FPVT.
Main Methods
- Simulated exercise effects on mutant RyR2 channels via protein kinase A (PKA) phosphorylation.
- Assessed calstabin2 binding affinity and channel function (IC50) in wild-type versus mutant RyR2 channels.
- Evaluated the impact of JTV519 treatment on calstabin2 binding and RyR2 channel function.
Main Results
- Three FPVT-associated RyR2 mutations (P2328S, Q4201R, V4653F) showed reduced calstabin2 binding and a gain-of-function defect after PKA phosphorylation.
- Mutant RyR2 channels exhibited leaky Ca2+ release and a rightward shift in Mg2+ inhibition (IC50).
- JTV519 treatment restored calstabin2 binding to RyR2 and normalized channel function.
Conclusions
- Sympathetic activation during exercise triggers ventricular arrhythmias in RyR2 mutation carriers above a threshold heart rate.
- PKA-induced gain-of-function defect in mutant RyR2 channels contributes to arrhythmogenesis.
- JTV519 demonstrates potential as a therapeutic agent by stabilizing the RyR2 channel complex and preventing exercise-induced arrhythmias and sudden death.
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