A recent molecular discovery by neuroscientists at Brown and Boston Children’s Hospital has brought researchers closer to finding a possible treatment for spinal muscular atrophy, a debilitating neuron disease that causes progressive muscle degeneration and weakness.
By testing a drug that normally treats ALS — also known as Lou Gehrig’s disease — in animal models of SMA, researchers found the drug affects channels that are implicated in the disease, a discovery which may provide insight into new treatments.
The research, published Wednesday in the Journal of Neuroscience, was largely sparked by the scientists’ increasing awareness of the interconnectedness of SMA and ALS, said Anne Hart, professor of neuroscience and senior author of the paper.
One of the most significant similarities between the diseases is that they both involve “SK” potassium channels, Hart said.
SMA — the leading genetic cause of infant death — is caused by the diminished function of the Survival Motor Neuron protein, according to the study. Riluzole, a drug commonly given to ALS patients, counteracts this genetic defect by restoring axon growth, the study reported.
“Riluzole makes neurons grow out the way they should,” Hart said.
Riluzole acts as a “dirty drug,” meaning that it binds to several different types of channels and changes the function of each, Hart said. By activating and deactivating each of these channels individually and studying the effects of Riluzole on each, the team was able to conclude that the drug acts through the SK channel, which is implicated in SMA and ALS, she said.
Though this is just the first step in understanding the SK channel’s role in SMA and ALS, further research could eventually lead to improved treatment of the diseases, Hart said. “This doesn’t mean that SMA patients should be asking physicians for Riluzole,” she said.
The researchers at Brown treated C. elegans worms with the drug, while partner researchers at Boston Children’s Hospital studied the drug in mice, giving the study “cross-species importance,” said Maria Dimitriadi, the study’s lead author and a postdoctoral researcher at Brown.
She added that it is “exciting” to “collaborate with people who work with other models.”
The researchers chose to work with a worm model primarily because the worms grow quickly and their “nervous systems are smaller and simpler, and you can find things faster,” Hart said.
The researchers plan to continue studying the SK channel in more detail, she added.
The scientists encountered just one primary technical obstacle over the course of their research — finding a worm with the disease, Dimitriadi said. While it normally takes researchers two to three weeks to find the desired model, it took them months to screen over 500 worms to find the “very exciting mutant,” Dimitriadi said.
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