Gene Therapy Breakthrough: High-Potency Capsids Enhanced Skeletal Muscle Correction in GSD IIIa Mouse Model

Researchers at Duke University School of Medicine have made significant advancements in gene therapy, utilizing high-potency capsids to enhance skeletal muscle correction in a mouse model of glycogen storage disease type IIIa (GSD IIIa). This groundbreaking research holds promise for the treatment of this debilitating genetic disorder, which affects multiple tissues, including the liver, heart, and skeletal muscles.

Key Takeaways:

• The study reported that the high-potency MyoAAV capsids, MyoAAV4A and MyoAAV4E, demonstrated remarkably greater transduction efficiency and glycogen clearance efficacy in the cardiac and skeletal muscles than the AAV9 vector.
• Administration of the MyoAAV vectors at a 10-fold lower dose (1 x 10^12 vg/kg) achieved significantly better therapeutic outcomes in the skeletal muscles than the AAV9-Dual-Pull vector at a high dose (1 x 10^13 vg/kg).
• The study highlighted the improved muscle function, reversal of liver abnormalities, and normalization of the disease biomarker, Glc4, in the urine after treatment with the MyoAAV vectors.
• Validation in human liver chimeric mice revealed that the MyoAAV vectors and the AAV9 vectors had a similar efficiency in transducing human hepatocytes, indicating increased translatability for clinical applications.
• The research was funded by the National Institute of Arthritis And Musculoskeletal And Skin Diseases.
• The study was conducted by researchers at Duke University School of Medicine, including Kuo-An Liao, Sang-oh Han, Mercedes Barzi, Haiqing Yi, William Eisner, Beatrice Bissig-Choisat, Karl-Dimiter Bissig, and Baodong Sun.

Statistics:

• 1:10^13 vg/kg: the dose of AAV9-Dual-Pull vector administered to mice.
• 1:10^12 vg/kg: the 10-fold lower dose of MyoAAV4A-Dual-Pull vector administered to mice, which achieved significantly better therapeutic outcomes.
• 33.3%: the percentage of transduced human hepatocytes achieved by the MyoAAV vectors in human liver chimeric mice.
• 23.4%: the percentage of transduced human hepatocytes achieved by the AAV9 vectors in human liver chimeric mice.
• 2025: the year in which the research was conducted and the study was published in Molecular Therapy: Methods & Clinical Development.

Sources:

• High-potency MyoAAV capsids enhanced skeletal muscle correction in a mouse model of GSD IIIa. Molecular Therapy: Methods & Clinical Development, 2025,33(3):101567.
• Molecular Therapy: Methods & Clinical Development. Publisher: Elsevier. DOI: 10.1016/j.omtm.2025.101567.