Photo credit: NASA Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is one of the most common neuromuscular diseases worldwide and attacks the neurons responsible for controlling voluntary muscles. Few treatment options are currently available for ALS patients but researchers at UT Southwestern Medical Center and Harvard University have shown that microRNA-206 (miR-206) plays a crucial role in the progression of ALS. miRNAs are small non-coding RNA molecules which down-regulate gene expression and dysfunction of miRNAs has been associated with a number of diseases. In ALS, as the affected neurons stop signalling to muscle cells, the muscles atrophy. Although the skeletal muscles attempt to reinnervate themselves by signalling to healthy neurons via miRNA-206, eventually the surviving neurons are unable to cope, the muscle cells die and the ability of the brain to control voluntary movement is lost.
Mice that are genetically deficient in miRNA-206 form normal neuromuscular synapses during development but, in the ALS mouse model, disease progression is faster in mice that are deficient in miRNA-206. miRNA-206 is required for efficient regeneration of neuromuscular synapses after acute nerve injury and is dramatically induced in the mouse model of ALS. The effects of miRNA-206 in slowing ALS were suggested to be mediated, at least in part, through histone deacetylase 4 and fibroblast growth factor signalling pathways. miRagen Therapeutics hope to exploit the newly discovered role for miRNA-206 in neuromuscular maintenance to develop treatments for patients suffering from ALS and other neuromuscular diseases. Because miR-206 is only produced by skeletal muscles, such treatments may have a limited risk of side effects.
The study is published in the journal Science.