In Vivo Ryr2 Editing Corrects Catecholaminergic Polymorphic Ventricular Tachycardia

Area of Science:

• Cardiovascular Genetics
• Molecular Cardiology
• Gene Therapy

Background:

• Autosomal-dominant RYR2 mutations cause catecholaminergic polymorphic ventricular tachycardia (CPVT), a lethal arrhythmia.
• RYR2 mutations lead to calcium handling abnormalities and ventricular tachycardia.
• In vivo CRISPR/Cas9 gene editing offers a potential therapeutic strategy for CPVT.

Purpose of the Study:

• To evaluate somatic in vivo genome editing using CRISPR/Cas9 delivered by adeno-associated viral (AAV) vectors.
• To correct CPVT arrhythmias in mice with a heterozygous RYR2 mutation (R176Q/+)

Main Methods:

• CRISPR/Cas9 system with guide RNAs targeting the R176Q RYR2 allele.
• Adeno-associated viral serotype 9 (AAV9) for in vivo delivery to neonatal mice.
• Assessment of arrhythmias, RYR2 expression, allele editing, and calcium handling.

Main Results:

• AAV-CRISPR treatment prevented arrhythmias in R176Q/+ mice (0% vs. 71% in controls).
• Significant reduction in RYR2 mRNA and protein levels observed.
• High specificity of SaCas9 editing confirmed, with no detectable off-target mutations.
• Gene editing normalized abnormal Ca2+ spark frequency.

Conclusions:

• AAV9-delivered SaCas9 efficiently disrupts the disease-causing RYR2 allele in cardiomyocytes in vivo.
• Somatic genome editing is a promising therapeutic approach for autosomal-dominant inherited cardiac disorders like CPVT.