By Josh Barney
Jung-Bum Shin, Ph.D., a 2006 Emerging Research Grants scientist, at the Association for Research in Otolaryngology MidWinter Conference in February 2023.
University of Virginia School of Medicine researchers have discovered how cells that let us hear can repair themselves after being damaged, an insight that could benefit efforts to treat and prevent hearing loss.
Sensory 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. When auditory hair cells are killed, they are gone for good, but the new UVA research shows these delicate cells can repair themselves from “sublethal” 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, says researcher Jung-Bum Shin, Ph.D., an associate professor in the UVA School of Medicine’s department of neuroscience.
“By gaining a deeper understanding of these inherent repair processes, we can uncover strategies to fortify them effectively,” Shin says.
One future approach may use drugs to stimulate cell repair, he says.
“When replacement of hair cells proves challenging, the focus shifts toward repairing them instead. This dual strategy of regeneration and repair holds strong potential in advancing treatments for hearing loss and associated conditions,” Shin says.
Hearing Repair
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 function.
Prolonged exposure to loud noise harms hair cells in a variety of ways, and one of those is by damaging the cores of the “hairs” themselves. These hair-like structures are known as stereocilia, and Shin’s new research shows a process they use to repair themselves when damaged.
The hair cells deploy a protein called XIRP2, which can sense damage to the stereocilia cores that are made of a substance called actin. Shin and his team found that XIRP2 first senses damage, then migrates to the damage site and repairs the cores by filling in new actin.
This process is also relevant to the broader study of cell biology, Shin says.
The pioneering work netted Shin and his colleagues more than $2.3 million from the National Institutes of Health (R01DC021176) to fund additional research into how the cores are repaired. By understanding this, scientists will be better positioned to develop new ways to battle hearing loss—even loss due to aging, the researchers say.
“Age-related hearing loss affects at least a third of all older adults,” Shin says. “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. Furthermore, this knowledge holds potential implications for associated conditions such as Alzheimer's disease and other dementia conditions.”
As the paper’s abstract concludes, “Our study describes a novel process by which hair cells can recover from sublethal hair bundle damage and which may contribute to recovery from temporary hearing threshold shifts and the prevention of age-related hearing loss.”
The researchers published their findings in the scientific journal eLife in June 2023.
This originally appeared on the University of Virginia website. The research was supported by the National Institutes of Health’s National Institute on Deafness and Other Communication Disorders, grants R01DC014254, R56DC017724, R01DC018842, R01DC011835 and 1F31DC017370-01. Additional support was provided by the Owens Family Foundation, the Virginia Lions Hearing Foundation, and a National Science Foundation CAREER Award. Jung-Bum Shin, Ph.D., is a 2006 Emerging Research Grants scientist.
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