Spatial and Multiomic profiling of muscle regeneration dynamics in Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is a pediatric degenerative myopathy caused by the absence of functional dystrophin. As a result, DMD muscles exhibit compromised myofiber integrity and increased susceptibility to mechanical damage. In early disease stages, muscles undergo repeated cycles of degeneration and regeneration; over time, however, this regenerative capacity declines, leading to the gradual replacement of muscle tissue with fat and fibrosis. While several signaling pathways have been identified as deregulated in dystrophic muscle, the cellular and molecular mechanisms underlying this regenerative exhaustion remain to be fully elucidated. To address this, we constructed a comprehensive cellular atlas of human dystrophic muscle using high-resolution spatial transcriptomics (Visium HD), capturing the cellular crosstalk within regenerative regions. Cell-to-cell communication analysis revealed activation of Notch signaling mediated by NOTCH3 in activated satellite cells. Immunostaining confirmed elevated NOTCH3 expression in both DMD patient samples and in the mdx mouse model at late disease stages. Silencing of NOTCH3 in primary myoblasts improved myogenic differentiation, pinpointing NOTCH3-mediated signaling as a contributor to regeneration impairment. To further dissect the dynamics of regeneration and infer the gene regulatory networks governing myogenic differentiation, we integrated paired snRNA-seq and snATAC-seq data from young, adult, and aged mdx mice. This analysis identified GLIS3 upregulation as an additional barrier to effective myogenesis. GLIS3 displayed an overall increase in dystrophic muscles, while silencing experiments enhanced differentiation in myoblasts. Together, our work reveals intrinsic defects in the dystrophic stem cell compartment that emerge during disease progression and hinder the execution of the myogenic program. These findings suggest NOTCH3 and GLIS3 as potential therapeutic targets to enhance regeneration and maintain muscle integrity in DMD. This study provides a high-resolution map of the dystrophic regenerative landscape and offers a valuable resource for future translational research.