Failure to Resolve Inflammation Contributes to Juvenile-Onset Cardiomyopathy in a Mouse Model of Duchenne Muscular Dystrophy.

ABSTRACT

The absence of dystrophin protein causes cardiac dysfunction in boys with Duchenne Muscular Dystrophy (DMD). However, the common mouse model of DMD (B10- mdx ) does not manifest cardiac deficits until late adulthood limiting our understanding of the mechanism and therapeutic approaches to target the pediatric-onset cardiac pathology in DMD. We show the mdx mouse model on the DBA/2J genetic background (D2- mdx ) displays juvenile-onset cardiomyopathy. Molecular and histological analysis revealed heightened leukocyte chemotactic signaling and failure to resolve inflammation, leading to chronic inflammation and extracellular matrix (ECM) fibrosis, causing cardiac pathology in juvenile D2- mdx mice. We show that pharmacologically activating the N-formyl peptide receptor 2 (FPR2) - a receptor that physiologically resolves acute inflammation, mitigated chronic cardiac inflammation and fibrosis, and prevented juvenile onset cardiomyopathy in the D2-mdx mice. These studies offer insights into pediatric onset of cardiac damage in DMD, a new therapeutic target, and identify a drug-based potential therapy.