Researchers were able to restore the hearing of mice partially deafened by loud noises by boosting key proteins in their ears.
The findings demonstrate the importance of cells and a protein called NT3 in the communication between the ears and the brain, the University of Michigan Health System reported.
The findings suggest supporting cells form the base for the hearing system's hair cells, which interact with the nerves that carry sound signals to the brain. It also showed how NT3 forms connections between these hair cells and nerve cells in a type of connection called a ribbon synapse.
"It has become apparent that hearing loss due to damaged ribbon synapses is a very common and challenging problem, whether it's due to noise or normal aging," said Gabriel Corfas, Ph.D., who led the team and directs the U-M institute. "We began this work 15 years ago to answer very basic questions about the inner ear, and now we have been able to restore hearing after partial deafening with noise, a common problem for people. It's very exciting."
The researchers used a novel genetic technique to allow mice to produce more NT3 in the cells of the inner ear after they were exposed to damaging loud noises. The team found mice with extra NT3 recovered their ability to hear much better than the control mice.
In the future the team plans to look into the role of NT3 in human ear cells, and look for drugs that could boost its production. Since the mice in the study did not suffer total hearing loss, it is unclear whether this finding could help lead to cures for true deafness. The findings could also have implications for neurodegenerative diseases in which nerve cell connections are lost.
"This brings supporting cells into the spotlight, and starts to show how much they contribute to plasticity, development and maintenance of neural connections," Corfas said.
The findings were published in a recent edition of the online journal eLife.
