The present invention relates to the identification of a microRNA, miR-208, that induces the expression of ²-myosin heavy chain (²-MHC) and represses fast skeletal muscle contractile protein genes. Inhibition of this function is proposed as a treatment for cardiac fibrosis, hypertrophy and/or heart failure, and augmentation of this function can be used to repress slow fiber genes and activate fast fiber genes in the treatment of musculoskeletal disorders.