How do you make a deaf mouse hear? Emory University tries gene therapy

The researchers induced growth of extra sensory hair cells. The arrows indicate places where you wouldn't normally see these cells.

How can you help deaf mice regain their ability to hear? It sounds like the first half of a joke, but it's not. Researchers at the Emory University School of Medicine are part of the way toward figuring out a method that could eventually work, using gene therapy that helped promote the growth of new sensory hair cells in the inner ear. But the treatment seemed to benefit pre-pubescent mice far more than adult ones.

Read about the details in the Journal of Neuroscience. But the gist of what they accomplished is this: Bringing the Atoh1 gene into the cochleae of young mice helped promote the growth of those sensory hair cells. (They did this by giving mice an antibiotic that turned on the gene.) Those hair cells, in turn, as the researchers note, both connected with neurons and produced electrical signals just like normal sensory hair cells would. Of course, as is often the case, there is a catch. Prepubescent mice--two weeks old or less--experienced the most benefit. Once they got older, Atoh1 didn't do very much.

There's a lot of promise here, in theory. Some day the method could eventually work in mice (and maybe people), in using gene therapy to grow sensory hair cells that connect to neurons and help restore hearing. But this early study indicates there may be age limitations as to how well the therapy will work. And researchers need to determine if the hair cells' ability to generate electrical signals will function in the context of actual hearing.  Subsequent work by the research team will focus on stimulating sensory hair cell growth in older animals, and then examining how well their hearing recovers once scientists induce Atoh1. They didn't test hearing recovery for the initial trial. For now, sensory hair cell regeneration was enough.

"We have shown that hair cell regeneration is possible in principal," Ping Chen, Emory associate professor of cell biology, said in a statement.

- read the release
- check out the journal abstract