Desmin is a modifier of dystrophic muscle features in Mdx mice

Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease, caused by dystrophin deficiency. Desmin is like dystrophin associated to costameric structures bridging sarcomeres to extracellular matrix that are involved in force transmission and skeletal muscle integrity. In the present study, we wanted to gain further insight into the roles of desmin which expression is increased in the muscle from the mouse Mdx DMD model. We show that a deletion of the desmin gene ( Des ) in Mdx mice (DKO, Mdx:desmin-/-) induces a marked worsening of the weakness (reduced maximal force production) as compared to Mdx mice. Fragility (higher susceptibility to contraction-induced injury) was also aggravated and fatigue resistance was reduced in DKO mice. Moreover, in contrast to Mdx mice, the DKO mice did not undergo a muscle hypertrophy because of smaller and less numerous fibers, with reduced percentage of centronucleated fibres. Interestingly, Desmin cDNA transfer with adeno-associated virus in 1-month-old DKO mice and newborn Mdx mice improved muscle weakness. Overall, desmin plays important and beneficial roles on muscle performance, fragility and remodelling in dystrophic Mdx mice.