Coexistence of AAV-microdystrophin gene therapy and mechanical load: Complementary synergistic effect of exercise demonstrated by transcriptomic analysis
##1. Clinical dilemma of exposing gene‑treated muscle to mechanical stress AAV‑mediated microdystrophin delivery for Duchenne muscular dystrophy (DMD) aims to restore structural stability of damaged muscle fibers. However, in the clinic there is a critical lack of data on whether microdystrophin expressed from the vector can provide sufficient durability when the treated muscle is subjected to continuous mechanical load (exercise), or whether it might instead provoke micro‑injury and recurrent inflammation. In particular, the long‑term transcriptomic response of the diaphragm—a muscle essential for respiration and constantly undergoing cyclic contraction‑relaxation stress—remains undefined.
##2. Tracking inflammatory and fibrotic signaling through diaphragm transcriptomics The research team administered AAV‑microdystrophin to mdx mice, a DMD model, and then subjected them to 21 weeks of voluntary wheel running. Diaphragm tissue, which experiences the harshest mechanical environment, was harvested for RNA‑sequencing. In untreated mdx mice, 2,881 genes (predominantly involved in inflammation and fibrosis pathways) were profoundly dysregulated. In the gene‑therapy‑only cohort, 774 of these genes were significantly “rescued” to wild‑type (WT) expression levels.
##3. 93 % structural retention: AAV‑mediated transgene expression withstands mechanical load The most striking finding concerns the transcriptomic profile of the cohort that received both gene therapy and 21 weeks of mechanical stress (exercise). Astonishingly, 93 % of the 774 rescued genes retained WT‑level expression in the exercise‑combined group. This provides molecular‑level evidence that the microdystrophin‑derived sarcolemmal complex can protect dystrophic muscle from physical collapse and recurrent inflammation even under sustained contraction.
##4. Paradigm shift in post‑gene‑therapy management protocols The importance of these data lies in the empirical basis they provide for fundamentally revising DMD gene‑therapy guidelines. Physical activity, previously limited due to concerns of muscle damage, can now be safely incorporated after AAV treatment as a complementary synergistic approach that enhances strength and endurance without triggering transcriptomic evidence of inflammation. Consequently, structured rehabilitation exercise should become an integral component of follow‑up protocols for patients receiving AAV‑based therapeutics.
Source: Skeletal Muscle & Gene Therapy Review, May 2026.
Summary: Utilizing transcriptomic analysis of the diaphragm in mdx mice, this study elucidates the molecular impact of long-term voluntary exercise following AAV-microdystrophin gene therapy. RNA sequencing revealed that AAV treatment rescued 774 dysregulated genes associated with inflammatory and fibrotic pathways. Crucially, 93% of these rescued genes maintained their normalized expression profiles despite 21 weeks of continuous physical activity, proving that mechanically induced stress does not abrogate the therapeutic efficacy of AAV-mediated gene transfer in dystrophic muscle.
These data constitute a rare and valuable reference that quantifies tissue resistance to mechanical load after AAV vector administration at the transcriptomic level. In particular, the 93 % maintenance of inflammatory‑pathway suppression in the diaphragm—the most mechanically demanding environment—can be directly employed as a key efficacy‑durability metric in ongoing development of next‑generation muscle‑targeted AAV capsids and promoter optimizations.