Stabilisation of calstabin2--a new approach in sudden cardiac death

Area of Science:

• Cardiology
• Molecular Biology
• Genetics

Background:

• Calstabin2 stabilizes the cardiac ryanodine receptor (RyR2), preventing its abnormal activation during diastole.
• Loss of calstabin2 stabilization is implicated in sudden cardiac death and atrial fibrillation in heart failure patients.
• Calstabin2-deficient mice exhibit exercise-induced ventricular arrhythmias and sudden death despite structurally normal hearts.

Purpose of the Study:

• To investigate the role of calstabin2 in cardiac arrhythmias and its potential as a therapeutic target.
• To evaluate the antiarrhythmic effects of the calstabin2 stabilizer JTV519 in different models of cardiac dysfunction.

Main Methods:

• Utilized calstabin2-deficient (calstabin2-/-) and heterozygous (calstabin2+/-) mice to study exercise-induced arrhythmias.
• Assessed the efficacy of JTV519 in preventing or reducing arrhythmias in these mouse models.
• Investigated the binding affinity of calstabin2 to wild-type and mutant human RyR2 (hRyR2) in HEK293 cells.
• Examined the effect of JTV519 on calstabin2 dissociation from RyR2 in vitro models of atrial fibrillation and heart failure.

Main Results:

• Calstabin2 deficiency leads to exercise-induced ventricular arrhythmias and sudden death in mice.
• JTV519 did not prevent arrhythmias in calstabin2-/- mice but reduced them in calstabin2+/- mice.
• Human RyR2 mutants associated with familial polymorphic ventricular tachycardia show reduced binding affinity for calstabin2.
• JTV519 reversed excessive calstabin2 dissociation from RyR2 in vitro models relevant to human atrial fibrillation and heart failure.

Conclusions:

• Calstabin2 is crucial for RyR2 stabilization and preventing cardiac arrhythmias.
• Targeting calstabin2 stabilization represents a promising therapeutic strategy for sudden cardiac death and atrial fibrillation.
• JTV519 demonstrates antiarrhythmic potential by stabilizing calstabin2-RyR2 interactions.