Engineered bacterial voltage-gated sodium channel platform for cardiac gene therapy

Area of Science:

• Biophysics
• Cardiovascular Biology
• Molecular Therapy

Background:

• Cardiac arrhythmias are often caused by impaired electrical excitability and conduction.
• Mammalian voltage-gated sodium channels are crucial for cardiac function but are too large for efficient gene therapy vectors.
• Developing smaller, effective sodium channel alternatives is essential for treating cardiac conduction disorders.

Purpose of the Study:

• To develop and evaluate a novel gene therapy platform using engineered prokaryotic sodium channels (BacNa_v) to enhance cardiac electrical properties.
• To assess the efficacy of BacNa_v in improving cardiomyocyte excitability and conduction, and reducing arrhythmias.
• To determine the safety and stability of BacNa_v expression in vivo.

Main Methods:

• Engineered small-size prokaryotic sodium channels (BacNa_v) were codon-optimized and driven by muscle-specific promoters.
• In vitro studies on rat and human cardiomyocytes assessed excitability and conduction.
• In silico analysis of adult cardiac tissues from multiple species was performed.
• Fibrotic cardiac cultures were used to evaluate the reduction of conduction block and arrhythmias.
• Self-complementary adeno-associated virus (scAAV) was used for in vivo delivery in mouse hearts.

Main Results:

• BacNa_v significantly enhanced excitability and action potential conduction in cardiomyocytes and cardiac tissues.
• Expression of BacNa_v reduced the occurrence of conduction block and reentrant arrhythmias in fibrotic models.
• Stable expression of functional BacNa_v channels was observed in mouse hearts six weeks post-injection via scAAV.
• No adverse effects on cardiac electrophysiology were detected in treated mice.

Conclusions:

• Engineered prokaryotic sodium channels represent a viable and effective tool for gene therapy aimed at enhancing cardiac electrical function.
• The BacNa_v platform demonstrates potential for treating cardiac conduction disorders by improving excitability and reducing arrhythmias.
• The diversity of prokaryotic sodium channels and the developed platform facilitate future development of BacNa_v-based cardiac gene therapies.