There is no biological cure for deafness—yet. We detect sound using sensory cells sporting microscopic hairlike projections, and when these so-called hair cells deep inside the inner ear are destroyed by illness or loud noise, they are gone forever. Or so scientists thought. A new study finds specific cells in the inner ear of newborn mice that regenerate these sensory cells—even after damage, potentially opening up a way to treat deafness in humans.
Researchers knew that cells in the inner ear below hair cells—known as supporting cells—can become the sensory cells themselves when stimulated by a protein that blocks Notch signaling, which is an important mechanism for cell communication. Albert Edge, a stem cell biologist at Harvard Medical School in Boston, and his colleagues, attempted to identify the exact type of supporting cells that transform into sensory ones and fill in the gaps left by the damaged cells.
The recent study follows a similar paper published earlier this month by developmental neurobiologist Jian Zuo, of St. Jude Children’s Research Hospital in Memphis, Tennessee, who damaged sensory cells in live mice. Zuo also saw regeneration of hair cells from supporting cells, but most of the new cells died within 2 weeks. In humans, the organ of Corti matures in the womb, but in mice, the organ continues to mature for the first 10 days of life, so these same findings may not hold true in humans.