Unlike previous experiments that focused on "genetic accelerators" this work shows that suppressing an inhibitor is a new way to build muscle. Examination under a microscope confirmed that the muscle fibers of the modified mice are denser, the muscles are more massive, and the cells in the tissue contain higher numbers of mitochondria—cellular organelles that deliver energy to the muscles.
Similar results were also observed in nematode worms, allowing the scientists to conclude that their results could be applicable to a large range of living creatures.
The scientists have not yet detected any harmful side effects associated with eliminating the NCoR1 receptor from muscle and fat tissues. Although the experiments involved genetic manipulations, the researchers are already investigating potential drug molecules that could be used to reduce the receptor's effectiveness.
The researchers say their results are a milestone in our understanding of certain fundamental mechanisms of living organisms, in particular the little-studied role of corepressors—molecules that inhibit the expression of genes. In addition, they give a glimpse at possible long-term therapeutic applications.
"This could be used to combat muscle weakness in the elderly, which leads to falls and contributes to hospitalizations," Auwerx says. "In addition, we think that this could be used as a basis for developing a treatment for genetic muscular dystrophy."
He added that if these results are confirmed in humans, there's no question they will attract interest from athletes as well as medical experts.