Inhibiting myostatin reverses muscle fibrosis through apoptosis.

Myostatin is both a regulator of muscle growth and a stimulator of muscle fibroblasts to proliferate; and there is an accumulating body of evidence that demonstrates inhibition of myostatin/ActRIIB signaling can ameliorate the pathology and function of dystrophic muscle in preclinical models of Duchene muscular dystrophy.

In a recent paper, Kathryn Wagner et al., (Inhibiting myostatin reverses muscle fibrosis through apoptosis; https://www.ncbi.nlm.nih.gov/pubmed/22685331) now shows that myostatin stimulates the proliferation of dystrophic muscle fibroblasts and increases their resistance to undergo apoptosis.

They demonstrate that pharmacological manipulation of myostatin signaling with the chimeric fusion protein ActRIIB.mFc led to fibroblast apoptosis in vitro and importantly, systemic treatment of adult mdx mice led to a significant increase in the number of muscle fibroblasts that underwent apoptosis.

This is an important finding with disease modifying potential; it demonstrates for the first time the ability of drug candidates that target this molecular pathway may reverse pre-existing fibrosis in a preclinical model of Duchenne muscular dystrophy as well as the potential to stimulate muscle regeneration.