Voluntary running sustains the correction of inflammation-related gene expression conferred by AAV gene therapy in mdx mice

Duchenne muscular dystrophy is a fatal disease characterized by persistent skeletal muscle degeneration, inflammation, and fibrosis. Gene therapy using an adeno-associated virus-derived vector and a microdystrophin transgene is currently under investigation in patients, but the impact of physical activity on long-term therapeutic outcome remains poorly understood. Recently, we reported that 21 weeks of voluntary wheel running complemented the positive endurance and muscle function outcomes of gene therapy in mdx mice. In the present study, we performed a transcriptomic analysis of the gene expression changes associated with functional recovery in the diaphragm with a focus on genes and signaling pathways related to the inflammatory response. RNA sequencing and bioinformatic analysis revealed 2,881 dysregulated genes in untreated and unexercised mdx mice including inflammatory and fibrotic signaling pathways frequently affected in Duchenne muscular dystrophy patients. Among the dysregulated genes, 774 were rescued toward WT level after adeno-associated virus microdystrophin injection. Importantly, 93% of the rescued genes were maintained by voluntary running, which indicates that physical exercise has no significant impact on the outcome of gene therapy-rescued genes in the mdx diaphragm. Our study provides vital information that could help guide DMD patient follow-up protocols after treatment with gene therapy.