Key to developing auditory neurons discovered

Scientists from University of California, San Diego have made a novel advancement that would open new avenues for developing drugs that treat congenital and acquired hearing impairment.

Loss of spiral ganglion neurons or hair cells in the inner ear is the leading cause of congenital and acquired hearing impairment.

They have found that Sox2, a protein that regulates stem cell formation, is involved in spiral ganglion neuron development.

"These findings may provide the first step toward regenerating spiral ganglion neurons, the nerve cells that send sound representations to the brain," said Dr Alain Dabdoub, co-investigator and assistant professor of surgery with the division of otolaryngology at the UC San Diego School of Medicine.

"This has significant implications for advances in cochlear implant technology and biological treatments for hearing loss," Dabdoub added.

In the cochlea, auditory neurons transmit sound vibrations conveyed by hair cells. These vibrations are then converted to nerve impulses that communicate with the brain. If the neurons are lost or damaged, hearing loss occurs.

"The identification of factors that induce functional neurons has important implications for hearing restoration," said Dr Chandrakala Puligilla, a research fellow at the National Institutes of Health.

"The ability to induce even a small number of cells with gene-based therapy could be enormously beneficial," Puligilla added.

The study demonstrates a novel role for Sox2 in ear development showing that Sox2 is critical for the production of auditory neurons and that generating new neurons is possible.

The study was published in the Journal of Neuroscience.