utricle in inner ear of a mouse

A kidney-shaped organ: changes in gene expression within the lining of the utricle, an organ within the inner ear responsible for detecting linear acceleration by the body. Utricle hair cells (red) of a mouse at the time of birth. (Rockefeller University)

Scientists at The Rockefeller University are working to find a way to regenerate the delicate sensory cells, or “hair cells,” of hearing and balance within the inner ear by examining how they develop in the first place. A research team from A. James Hudspeth’s Laboratory of Sensory Neuroscience, has identified two genes pivotal to the production of hair cells in young mice, who, just like human babies, lose the ability to generate these sensors shortly after birth.

According to an article published in the October 26, 2015 edition of the Proceedings of the National Academy of Sciences, the researchers examined changes in gene expression in the utricle, a hair cell-lined organ within the inner ear that detects motion. They saw that the activity of two genes dropped dramatically shortly after the mice were born and hair cells ceased to develop in their utricles. These genes code for the proteins Sox4 and Sox11, which play a role in shaping the identity cells assume by regulating the expression of other genes.

First author, Ksenia Gnedeva, a postdoc in the lab, tested these proteins’ involvement in hair cell formation by altering their expression. When both genes were shut down, Gnedeva found that the entire inner ear, not just the utricle, developed abnormally. In other experiments, Gnedeva turned on the genes in older mice whose hair cells were fully matured, and discovered that this gene activation could induce the production of new hair cells within a fully developed utricle.

The research team is now reportedly exploring the series of molecular interactions that normally lead to the activation of these proteins and the steps that follow.

“Our ultimate goal is to find a target that would allow us to restore hair cells later on in life,” said Gnedeva in an announcement from The Rockefeller University. “It appears possible that these proteins, or perhaps other steps in the same pathway, might be potential targets.”

A. James Hudspeth, MD, PhD

A. James Hudspeth, MD, PhD

Hudspeth, the study’s senior author, is the F.M. Kirby Professor at Rockefeller and an investigator with the Howard Hughes Medical Institute.

Source: The Rockefeller University 

Photo credits: A. James Hudspeth, The Rockefeller University