S100A1 DNA-based Inotropic Therapy Protects Against Proarrhythmogenic Ryanodine Receptor 2 Dysfunction

Area of Science:

• Cardiology
• Molecular Biology
• Biochemistry

Background:

• Restoring S100A1 protein levels is crucial for normal calcium handling in heart failure (HF).
• S100A1 enhances sarcoplasmic reticulum (SR) function but may increase SR calcium leakage, risking arrhythmias.
• The interaction between S100A1 and ryanodine receptors (RyR2s) in HF is not well understood.

Purpose of the Study:

• To investigate the interaction between S100A1 and RyR2 in experimental heart failure.
• To determine if restoring S100A1-RyR2 interaction can prevent proarrhythmic calcium leakage.
• To elucidate S100A1's role in regulating diastolic RyR2 activity and its therapeutic potential in HF.

Main Methods:

• Investigated S100A1-RyR2 interaction in experimental HF models.
• Utilized adenoviral and adeno-associated viral S100A1 cDNA delivery in cardiomyocytes, engineered heart tissue, and mouse hearts.
• Assessed RyR2 function, SR calcium handling, and arrhythmogenesis in vitro and in vivo.

Main Results:

• A diminished S100A1-RyR2 interaction was observed in experimental HF.
• Restoring this interaction normalized diastolic RyR2 function and prevented SR calcium leakage.
• S100A1 inhibited diastolic SR calcium leakage despite aberrant RyR2 phosphorylation and altered stoichiometry with modulators.
• S100A1 delivery protected against basal and catecholamine-triggered arrhythmias in HF models.

Conclusions:

• S100A1 is a key regulator of diastolic RyR2 activity and dysfunction in HF.
• Restoring S100A1-RyR2 interaction is a viable strategy to protect against arrhythmias in HF.
• S100A1 offers both antiarrhythmic and chronic inotropic benefits in heart failure treatment.