CHICAGO, Ill. — Thanks to the discovery of a “master gene,” scientists can now create new hearing cells that can overcome age-related deafness.
The genetic discovery allows for the production of new inner or outer ear hair cells. Until now, hearing loss due to aging, noise, and certain cancer therapies or antibiotics has been irreversible because it hasn’t been possible to reprogram existing cells to hear when actual ear cells die.
This single master gene, however, can change ear cells into either outer or inner sensory hair ones.
According to the National Institutes of Health, one in eight people in the United States over the age of 12 deals with hearing loss in both ears. Roughly nine percent of all adults between 55 and 64 have disabling hearing loss — a number that jumps to 25 percent among adults 65 to 74 and 50 percent among those 75 and older.
Currently, scientists can produce an artificial hair cell, but it does not differentiate into an inner or outer cell, which provides different essential functions to produce hearing. The discovery is a major step toward developing these specific cells.
Repairing the ‘ballet’ inside the ear
The death of outer hair cells created by the cochlea is most often the cause of deafness and hearing loss. The cells develop in the embryo and do not reproduce.
The outer hair cells expand and contract in response to the pressure of sound waves and amplify sound for the inner hair cells. The inner cells transmit those vibrations to the neurons to create the sounds we hear. Finding the master gene switch, which scientists call TBX2, allows the team to create an inner or outer cell.
“Our finding gives us the us the first clear cell switch to make one type versus the other,” says Professor Jaime Garcia-Anoveros of Northwestern University in a media release. “It will provide a previously unavailable tool to make an inner or outer hair cell. We have overcome a major hurdle.”
“It’s like a ballet,” Dr. Garcia-Anoveros adds. “The outers crouch and jump and lift the inners further into the ear.”
“The ear is a beautiful organ. There is no other organ in a mammal where the cells are so precisely positioned. (I mean, with micrometric precision). Otherwise, hearing doesn’t occur,” the researcher continues. “We can now figure out how to make specifically inner or outer hair cells and identify why the later are more prone to dying and cause deafness.”
The study is published in the journal Nature.
South West News Service writer Joe Morgan contributed to this report.