AAVmyo2 Serotype

Characteristics

AAVS1 was isolated by in vivo cycling of shuffled AAV1/6/8/9 libraries in mouse quadriceps, diaphragm and heart, but was less efficient than AAVMYO. Inserting P1 in variable region VIII (G585-L594 in the modeled AAVMYO3 VP3 monomer) raised mRNA barcode counts in muscle above those of AAVS1, to within twofold of AAVMYO, with barcodes nearly absent in liver and brain (CMV-eyfp, C57BL/6J and NMRI mice). Luciferase under hDES or SPc5-12 promoters (1e11 vg, CB17 mice) was undetectable in liver. Human seroprevalence is comparable to AAV9 (ELISA, neutralization).

Applications: Intravenous gene delivery to skeletal muscle, diaphragm and heart in mice. In Mtm1-KO mice (X-linked myotubular myopathy), MTM1 vectors under the DES promoter at 4e12, 2e13 and 1e14 vg/kg rescued survival of all treated animals, and AAV8 did so only at 1e14 vg/kg. Producible in 10 L HEK293T bioreactor cultures at 2- to 4-fold higher titers than AAV8.

Limitations: Tested in mice only; the cellular receptor is unknown. No Duchenne model data are reported for AAVMYO2. In Mtm1-KO mice the 4e12 vg/kg dose did not normalize TA fiber size, and 1e14 vg/kg gave abnormal small TA myofibers and cardiac fibrotic lesions. Replacing P1 with peptide P4 in AAVS10 shifted vector toward liver with much lower muscle activity.

References

1. El Andari et al. (2022). Semirational bioengineering of AAV vectors with increased potency and specificity for systemic gene therapy of muscle disorders. Sci Adv - El Andari 2022 AAVMYO2 AAVMYO3