Towards a better understanding of inherited hearing loss

October 15, 2013

A team of researchers led by Dr. Michel Cayouette at the IRCM made an important discovery, published online yesterday by the scientific journal Developmental Cell, that could better explain some inherited forms of hearing loss in humans. The Montréal scientists identified a group of proteins crucial for shaping the cellular organ responsible for detecting sounds.

For a human to hear, sound-induced vibrations in the inner ear must first be transformed into electrical impulses before they can be relayed to the brain. This transformation is performed by "" (or sensory cells) located in the . On the surface of these cells, microscopic hair-like protrusions known as stereocilia act as specialized sensors to detect vibrations.

"During embryonic development, these stereocilia develop into a characteristic V-shaped brush," says Dr. Cayouette, Director of the Cellular Neurobiology research unit at the IRCM. "In addition, all cells orient their brush with the V pointing in the same direction. This polarized organization is critical for sensory function, but remains poorly understood."

"We studied a group of proteins known to control cell division in the organism and discovered a new role they play in the auditory system," explains Dr. Basile Tarchini, postdoctoral fellow in Dr. Cayouette's laboratory and first author of the study. "We showed that these proteins occupy a specific region at the to define the exact placement of stereocilia and enable the creation of the V-shaped brush."

"Furthermore, we discovered that one of the proteins is also required for coordinating the orientation of the brushes among neighbouring cells, thereby ensuring that the V formed by each brush points in the same direction," adds Dr. Tarchini. "Our results strongly suggest, for the first time, that this group of proteins could be the link between two important molecular mechanisms: the system responsible for the placement of stereocilia into a V-shaped brush at the cell surface, and the system that orients this V-shaped structure in the surrounding tissue."

"Recent studies show that mutations in one of the proteins we studied are associated with inherited forms of in humans," concludes Dr. Cayouette. "By defining a function for this class of proteins in hair , our work helps explain the mechanisms that could cause these conditions."

Explore further: New findings on the workings of the inner ear

More information: www.cell.com/developmental-cell/abstract/S1534-5807(13)00537-6

Related Stories

New findings on the workings of the inner ear

October 2, 2012

The sensory cells of the inner ear have tiny hairs called stereocilia that play a critical part in hearing. It has long been known that these stereocilia move sideways back and forth in a wave-like motion when stimulated ...

Hearing loss clue uncovered

June 11, 2013

(Medical Xpress)—Researchers from the Department of Otolaryngology at the University of Melbourne and the Department of Biochemistry and Molecular Biology at Monash University have discovered how hearing loss in humans ...

Cellular channels vital for hearing identified

July 18, 2013

Ending a 30-year search by scientists, researchers at Boston Children's Hospital have identified two proteins in the inner ear that are critical for hearing, which, when damaged by genetic mutations, cause a form of delayed, ...

Recommended for you

New method creates endless supply of kidney precursor cells

August 25, 2016

Salk Institute scientists have discovered the holy grail of endless youthfulness—at least when it comes to one type of human kidney precursor cell. Previous attempts to maintain cultures of the so-called nephron progenitor ...

Strict diet combats rare progeria aging disorders

August 25, 2016

Mice with a severe aging disease live three times longer if they eat thirty percent less. Moreover, they age much healthier than mice that eat as much as they want. These are findings of a joint study being published today ...

New avenue for understanding cause of common diseases

August 25, 2016

A ground-breaking Auckland study could lead to discoveries about many common diseases such as diabetes, cancer and dementia. The new finding could also illuminate the broader role of the enigmatic mitochondria in human development.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.