A MOLECULAR-LEVEL failure to communicate may be behind the disastrous breakdown of muscular discourse that characterizes spinal muscular atrophy, SMA, a deadly neuromuscular disease affecting one in every 10,000 children born in the United States.
In a recent study using rodents, a team of MU life scientists determined that the complex chemical signals used by motor neurons to communicate with muscle tissue fail to be delivered, making it impossible for nerve and muscle to converse normally.
It’s an insight that could provide important ammunition in the fight against SMA and other diseases involving motor neurons, including amyotrophic lateral sclerosis and dysfunctions of the synapses, such as Duchenne Muscular Dystrophy.
“Moving involves an intricate system of communication between the brain, peripheral nerves and muscles,” says Michael Garcia, an associate professor of biological sciences at MU and lead author of the study.
“Motor neurons facilitate this communication through a complex series of chemical signals. If the communication system breaks down, the motor neuron will stop working and muscle activity ceases,” Garcia says.
SMA affects those born missing both copies of the SMA 1 gene and with fewer copies of a less functional SMN 2 gene. It causes progressive weakness and degeneration of skeletal muscles, slowly robs the body of its ability to walk, stand, sit and, eventually, move at all.
The most severe form of the disease manifests itself within the first six months of life. Few infants diagnosed at this stage live past age 2. Milder forms of SMA cause symptoms much later, sometimes not appearing until well into adulthood.
There is no cure, but Garcia hopes findings like his will lay the groundwork for future treatments.
“By learning where the system breaks down, perhaps we can target treatments that prevent these breakdowns,” he says.
The research was published in the September 2011 issue of ACTA Neuropathology. Garcia co-authored the report with MU researchers Jeffrey M. Dale, Devin M. Barry, Virginia Garcia, Ferrill Rose, Jr. and Christian Lorson.