Figure 1.

Systemic AAV-9 Injection Leads to Robust Expression of a Five-Repeat Micro-Dystrophin Gene in the Skeletal Muscle and Heart of DBA/2J-mdx Mice

(A) Schematic illustration of the AAV microgene vector. Micro-dystrophin consists of the N-terminal domain, two hinges (H1 and H4), five spectrin-like repeats (R1, R16, R17, R23, and R24), and the cysteine-rich (CR) domain. Micro-dystrophin expression is regulated by the muscle-specific CK8 promoter. (B) Representative dystrophin immunostaining photomicrographs demonstrating widespread microgene expression in the quadriceps, TA muscle, and diaphragm in treated DBA/2J-mdx mice. (C) A representative dystrophin western blot showing micro-dystrophin (μDys) at the expected size in AAV-treated muscles. (D) Representative immunostaining photomicrographs demonstrating robust myocardial micro-dystrophin expression in treated DBA/2J-mdx mice. Full-length dystrophin in the control DBA/2J heart reacted with both R11- and R17-specific antibodies. Therapeutic micro-dystrophin was recognized by the R17-specific but not the R11-specific antibody. (E) A representative dystrophin western blot showing abundant μDys at the expected size in the heart of treated DBA/2J-mdx mice. (F) Quantitative evaluation of AAV genome distribution in muscle and internal organs using in AAV microgene-injected female DBA/2J-mdx mice (n = 5). TaqMan qPCR detects the junction of R1-R16. Error bars are mean ± SEM. (G) Quantitative evaluation of AAV genome distribution in muscle and internal organs using in AAV microgene-injected female DBA/2J-mdx mice (n = 5). Error bars are mean ± SEM. TaqMan qPCR detects the junction of R17-R23. Dia, diaphragm; FL-Dys, full-length dystrophin; Gas, gastrocnemius; ITR, inverted terminal repeat; Quad, quadriceps; TA, tibialis anterior.