Aav-mediated Myostatin Propeptide Gene Delivery Results in Growth and Hypertrophy of Skeletal but Not Cardiac Muscle

AND HYPERTROPHY OF SKELETAL BUT NOT CARDIAC MUSCLE *Qiao, C; *Li, J; *Zhu, T; *Wang, B; *Chen, C; *O’Day, T; *Watchko, J; *Li, J; +*Xiao,X + University of Pittsburgh, Pittsburgh, PA [email protected] INTRODUCTION Myostatin was discovered as a new member of the transforming growth factor β (TGF-β) superfamily (1). Myostatin-deficient mice (1) and cattle (2) have shown to have a large increase in skeletal muscle mass (3, 4). Recently, a myostatin mutation in a child with muscle hypertrophy has been identified (5), which further indicates that myostatin is a negative regulator of muscle mass. Several strategies, including blocking antibody administration and propeptide injection, have been described to target myostatin and promote muscle growth in vivo. In this study, we hypothesized that systemic delivery of adenoassociated virus (AAV) vector carrying propeptide gene, a myostatin inhibitor, could increase skeletal muscle mass in both neonate and adult injected mice.