1Research Center for Genetic Medicine, Children’s National Hospital, Children’s National Research and
Innovation Campus, 7144 13th Pl NW, Washington, DC 20012
2Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological
Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
3 Department of Genomics and Precision Medicine, George Washington University School of Medicine
and Health Sciences, Washington, DC 20012
Dysferlinopathy is a degenerative muscle disease characterized by the progressive fibrofatty replacement of muscle fibers. Histological analysis of dysferlin-deficient muscle reveals variable pathology, driven by focal myofiber damage, regeneration, and degeneration occurring asynchronously across adjacent muscle regions. As a result, the diverse cell types within the muscle are exposed to unique microenvironments shaped by neighboring cells and the extracellular matrix, collectively affecting muscle health and function.
To better understand this focal heterogeneity in dysferlinopathic muscle, we employed spatial transcriptomics using the ‘Visium’ platform to generate spatial gene expression profiles from symptomatic and asymptomatic muscles in dysferlin-deficient mice, compared to matched healthy wild-type mice. We then integrated these data with spatial deconvolution techniques using sc/snRNA-seq reference datasets, allowing us to monitor transcriptomic changes in skeletal muscle at near-cellular resolution throughout disease progression.
Our analysis revealed a reduction in the relative abundance of Type II muscle fibers, smooth muscle cells, and neuromuscular junctions in dystrophic areas. In contrast, we observed an accumulation of damaged and regenerating myofibers, as well as tenocytes, macrophages, and fibro-adipogenic progenitors involved in disease progression. These regional changes in cell distribution and the transcriptomic profiles of muscle fibers and surrounding stromal cells provide new insights into the regulation of the muscle tissue microenvironment in dysferlinopathy and how these changes contribute to fibrofatty muscle loss.