Correction of the Dystrophic Phenotype by In Vivo Targeting of Muscle Progenitor Cells

Successful gene therapy for most inherited diseases will require stable expression of the therapeutic gene. This can be addressed with integrating or self-replicating viruses by targeting postmitotic cells that have a long lifetime or stem cells that can replenish defective tissue with corrected cells. In this study, we explore the possibility of targeting a muscle stem cell population in situ through in vivo administration of vector. To develop this concept, we selected a mouse model of muscular dystrophy (mdx mice) that undergoes rapid turnover of muscle fibers. In vivo targeting of muscle progenitor cells, notably satellite cells, with a pseudotyped lentiviral vector encoding the minidystrophin restores dystrophin expression and provides functional correction in skeletal muscle of max mice. This study shows that progenitor cells can be genetically engineered in vivo and subsequently proliferate into terminally differentiated tissue carrying the genetic graft in a way that stably corrects function.