Duchenne muscular dystrophy (DMD) is a serious neuromuscular disease caused by a dystrophin deficiency. Desmin, like dystrophin, is associated with costameric structures connecting the sarcomeres to the extracellular matrix which contributes to muscle function.
In this study, French experts including researchers from the Institute of Myology tried to provide additional information on the roles of desmin, whose expression is increased in muscle from the DMD mdx mouse model.
They showed that the suppression of the desmin (Des) gene in mdx mice (DKO, mdx: desmin – / -) induces marked muscle weakness, that is to say a production of reduced absolute absolute strength and increased fatigue. compared to that of mdx mice. Fragility, i.e. greater sensitivity to contraction-induced injuries, was also worsened in DKO mice compared to mdx mice, despite the presence of supposedly less fragile muscle fibers in DKO mice , and this worsening of frailty was linked to a decrease in muscular excitability.
In addition, unlike mdx mice, DKO mice did not undergo muscular hypertrophy, as evidenced by the increasingly smaller fibers, with a reduced percentage of centronucleated fibers, potentially explaining severe muscle weakness. In particular, the transfer of Desmin cDNA with the adeno-associated virus in newborn mdx mice improved the maximum specific strength normalized to muscle weight. Overall, desmin plays important and beneficial roles in muscle wasting, performance, and frailty in dystrophic mdx mice, which differ, at least in part, from those seen in healthy muscles.
