RNA sequencing of TA skeletal muscle of mice with conditional ablation of dystrophin within the myofiber

We generated and analyzed a conditional Dystrophin flox52/Y: human alpha-skeletal actin muscle knockout (Dmd flox52/Y: HSA mKO) model by targeting exon 52 deletion in the Dystrophin gene to study the consequences of dystrophin loss in skeletal muscle lineages. The generated DMD mouse model ablates dystrophin protein expression after mating with a Cre recombinase transgenic mouse under the control of HSA promoter element that is restricted to the skeletal muscle. The resulting Dmd mKO mice have been assessed using histopathological, phenotypical, functional and biochemical assays based on TRET-NMD standard operating protocols (SOPs) for mdx mouse models. Phenotypic analysis of these conditional Dmd mKO mice revealed a significant decline in locomotor activity and reduced muscle force, motor and muscular function. The histochemical analysis revealed an increase in centralized myonuclei and fibrotic area similar to mdx mice. Immunoassays including western blot and immunohistochemistry confirmed low expression levels of dystrophin in skeletal muscles of Dmd mKO mice. Bulk RNA sequencing analysis revealed that dystrophin loss in myofiber significantly disrupted the expression of cytokines and extracellular matrix genes.