Testing A Genetic 'Ad-Blocker' To Treat A Rare Neurological Disease

Researchers at the University of Chicago are using a novel approach to try to halt a rare neurological disorder: a sort of genetic "ad-blocker" that appears to be effective — at least in baby mice.

The disorder, Spinocerebellar ataxia type 6, or SCA6 for short, is a rare neurological disease, as are ALS (Lou Gehrig's Disease) and Parkinson’s. Researchers identified the gene that codes for the disease-causing protein in SCA6, but there was one problem. The gene that controlled the disease-causing protein also coded for a second protein that is essential for life.

Think of it this way: You click on a link to watch a movie, but as soon as you click on it, the movie opens but so does a virus that destroys your computer. How do you watch the movie without breaking your computer? Downloading an ad-blocker would do the trick. The researchers needed something similar.

So, to treat the disease, researchers had to find a way to turn off the disease-causing protein without turning off the protein essential for life. What they needed was a genetic ad-blocker and they found just that in a tiny piece of genetic material, called a microRNA.

"A microRNA is a small sequence of RNA made by separate genes that are naturally involved in gene regulation,” said Dr. Christopher Gomez, a neurology professor at the University of Chicago and the study's lead researcher.

Unfortunately, the biologists couldn't just download an ad-blocker for the gene, so they infected sick mice with a modified virus containing the ad-blocking microRNA. Mice that received the virus performed better on motor tests than untreated mice, showing the microRNA protected the mice from neuronal degeneration and ataxia.

"Most people would not be excited about having a virus deliver the miRNA," Gomez joked.

That’s OK because if purposely infecting yourself with a virus isn’t your preferred method of medicine, the researchers think that manufactured pieces of DNA could work similarly. They have even found several drugs that have shown promise working like the microRNA as a molecular ad-blocker.

Though research was done in newborn mice and must be replicated in adult mice before being considered for trials in humans, which could take years, it may someday have very far-reaching effects.

This strategy in general could have a much wider use.

Spinocerebellar ataxia’s similarity to diseases like ALS and Parkinson’s may allow this ad-blocker method to be used in treatment of those diseases. There are also some cancers that are caused by a similar genetic mutation that might respond to an ad-blocker treatment, researchers said.

The study appears in the new issue of Science Translational Medicine.


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