Inflammation in a severe model of dystrophic cardiomyopathy contains a high proportion of T-cells that contribute to onset of pathology
Duchenne muscular dystrophy (DMD) is a severe neuromuscular disorder characterized by progressive muscle degeneration and cardiomyopathy leading to heart failure. While the inflammatory environment in dystrophic skeletal muscle has been well-studied, little is known about inflammation in the progression of DMD cardiomyopathy due to the lack of adequate animal models. To address this, we developed the Fiona/dko mouse model, which exhibits severe, isolated dystrophic cardiomyopathy. In this study, we used Fiona/dko mice to characterize the immune cell composition in dystrophic heart and investigated the contribution of T-cells to the onset and progression of cardiac pathology. Flow cytometry analysis revealed that T-cells constitute a significant proportion of the immune cell population in Fiona/dko hearts, in contrast to the predominantly myeloid signature observed in dystrophic skeletal muscle. Furthermore, we demonstrated that T-cell infiltration precedes the development of cardiac fibrosis and dysfunction in Fiona/dko mice and that depletion of circulating CD3+ T-cells ameliorates early pathology, suggesting a role for T-cells in the initiation and persistence of dystrophic cardiomyopathy. These findings highlight the distinct inflammatory environment in the dystrophic heart and provide new insights into the pathogenesis of DMD cardiomyopathy, paving the way for the development of targeted anti-inflammatory therapies. Overall design: To investigate gene expression differences between more severe cardiomyopathy in Fiona/dko mice compared to less severe Het/Fiona mice, 9-month-old mice of each genotype, including males and females for each, were dissected and RNA was extracted from heart ventricles to send for bulk RNA sequencing.