A new study done in mice suggests that turning off a small genetic regulator called microRNA-33 (miR-33) might improve muscle regeneration and reduce damage in people with Duchenne muscular dystrophy (DMD).
While therapies for DMD focus on managing symptoms and improving quality of life, there is no cure for the disease, which often leads to loss of mobility in childhood and life-threatening complications in early adulthood. The researchers say that their findings, recently published in EMBO Molecular Medicine, could one day lead to a new therapeutic approach for DMD.
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MicroRNAs are short strands of RNA that help regulate gene activity. One of these molecules in particular, miR-33, is known for controlling fat and cholesterol metabolism, but the new study revealed that it also plays a role in suppressing muscle repair development and regeneration.
When the researchers genetically removed miR-33 from mice, they saw faster and more complete healing following muscle injury. These mice had less fibrosis (scar tissue) and stronger muscle fibers. In contrast, mice engineered to produce more human miR-33 experienced worse muscle degeneration and more fibrosis.
The researchers also found that miR-33 inhibits the ABCA1, CDK6 and FST genes, which all play an important role in muscle repair. By using short strands of synthetic DNA to block miR-33, the research team was able to restore expression of these helpful genes and improve muscle repair in the mice. They used the same miR-33-blocking strategy in a lab experiment in muscle cells grown from people with DMD and saw similar positive results.
While more research is needed to further test the effects of miR-33 inhibition, the study’s authors say their findings suggest this approach may one day be helpful to humans with the disease.
“miR-33a/b inhibition may be a novel therapeutic approach for patients with muscular dystrophy, including DMD, by targeting multiple pathways,” they concluded.
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