New process that repairs damaged hearing cells discovered

Researchers have found how cells that allow us to hear can repair themselves after being damaged, an advance that could boost efforts to treat and prevent hearing loss.

“Hair cells” found in the inner ear are important both for the ability to hear and for a sense of balance. They are known as hair cells because they are covered in hair-like structures that serve as mechanical antennas for sound detection.

The study, published in the journal eLife, shows the delicate hearing cells can repair themselves from damage caused by loud noises or other forms of stress.

For many years, research has focused on regeneration of sensory hair cells. Although those efforts continue, it is equally important to better understand the mechanisms that govern repair and maintenance of the cells.

“By gaining a deeper understanding of these inherent repair processes, we can uncover strategies to fortify them effectively,” said Jung-Bum Shin, from the University of Virginia School of Medicine, US.

Future approaches may use drugs to stimulate cell repair, he said.

“When replacement of hair cells proves challenging, the focus shifts towards repairing them instead. This dual strategy of regeneration and repair holds strong potential in advancing treatments for hearing loss and associated conditions,” Shin said. Hair cells are naturally fragile. They must be delicate so they can sense sound, but they must also withstand the continuous mechanical stress inherent in their working. Prolonged exposure to loud noise harms hair cells in a variety of ways, and one of those is by damaging the cores of the cells themselves.

These hair-like structures are known as stereocilia, and the new research shows a process they use to repair themselves.

The hair cells deploy a protein called XIRP2, which can sense damage to the cores that are made of a substance called actin.

The team found that XIRP2 first senses damage, then migrates to the damage site and repairs the cores by filling in new actin.

“Age-related hearing loss affects at least a third of all older adults. Understanding and harnessing internal mechanisms by which hair cells counteract wear and tear will be crucial in identifying ways to prevent age-related hearing loss,” Shin said.

“Furthermore, this knowledge holds potential implications for associated conditions such as Alzheimer’s disease and other dementia conditions,” the researcher added.