THURSDAY, Dec. 10 (HealthDay News) -- Researchers have identified a molecule that can reduce symptoms and prolong the life of mice with a type of amyotrophic lateral sclerosis (ALS).
The molecule, called microRNA-206 (miR-206), is produced naturally by skeletal muscles in response to nerve damage caused by ALS, also known as Lou Gehrig's disease. The molecule acts as a chemical signal to guide new nerve endings and maintain their interactions with muscles.
However, this research in mice suggests that miR-206 only works for a limited period of time. As nerves continue to die because of ALS, eventually surviving nerves can no longer compensate and symptoms such as muscle weakness begin to develop.
"While miR-206 initially prompts nearby surviving nerves to send new branches to the muscles, it only delays the inevitable," study senior author Eric Olson, chairman of molecular biology at the University of Texas Southwestern Medical Center, said in a university news release.
"Our findings correlate with the observation in ALS patients that the disease is nearly asymptomatic until a large fraction of motor neurons has died, at which point the few remaining ones can't compensate sufficiently," he explained. "These results provide a new perspective on the mechanisms of ALS. MiR-206 seems to sense nerve injury and promote regeneration."
These findings may help in efforts to develop drugs to treat ALS. Currently there is no cure or treatment to slow progression of the disease, which causes muscle weakness, paralysis and death.
"Because miR-206 only exists in skeletal muscle, a drug based on it might not affect other tissues. That limits its risk of side effects and is a key part of its appeal as a potential therapy," Olson added.
The study appears in the Dec. 11 issue of the journal Science.
The ALS Association has more about amyotrophic lateral sclerosis.
SOURCE: University of Texas Southwestern Medical Center, news release, Dec. 10, 2009