Challenges and opportunities in dystrophin-deficient cardiomyopathy gene therapy

Area of Science:

• Biomedical Engineering
• Molecular Biology
• Cardiology

Background:

• Gene therapy has advanced significantly for Duchenne and Becker muscular dystrophy (DMD/BMD) skeletal muscle. Cardiomyopathy is a major cause of death in DMD, BMD, and X-linked dilated cardiomyopathy, yet cardiac gene therapy remains underdeveloped.
• Key components for effective gene therapy include the gene, vector, delivery method, target tissue, and animal models. Significant efforts have focused on optimizing gene transfer vectors and delivery systems, with adeno-associated viral vectors showing widespread transduction in rodent hearts.

Purpose of the Study:

• This review addresses critical, often overlooked, aspects of cardiac gene therapy for muscular dystrophies.
• It aims to define essential parameters for successful heart gene therapy, focusing on candidate genes, optimal expression levels, and target tissues.
• Future research directions are highlighted, including evaluating mini- and microgenes, assessing partial gene correction efficacy, determining risks of overexpression, and understanding the impact of skeletal muscle correction on cardiomyopathy progression.

Main Methods:

• Review of current literature on gene therapy for muscular dystrophies, with a focus on cardiac applications.
• Analysis of the fundamental components of gene therapy: gene, vector, delivery, target tissue, and animal models.
• Discussion of challenges and future research needs in cardiac gene therapy, including specific questions regarding gene efficacy and model systems.

Main Results:

• Recombinant adeno-associated viral vectors have demonstrated effective transduction in rodent hearts via systemic and/or local delivery.
• The review identifies key unresolved challenges, including the selection of optimal therapeutic genes (full-length vs. mini-/microgenes), determining necessary expression levels, and defining the ideal target tissue.
• The potential benefits of partial gene correction and the risks associated with gene overexpression in the cardiac context require further investigation.

Conclusions:

• Significant progress in skeletal muscle gene therapy for DMD/BMD contrasts with the limited advances in cardiac gene therapy.
• Further research is crucial to determine the efficacy of various gene-based approaches, including mini-/microgenes and partial correction strategies, for treating cardiomyopathy in muscular dystrophies.
• Evaluating the suitability of current animal models and understanding the interplay between skeletal and cardiac muscle gene correction are essential for developing effective cardiac gene therapies.