Insight gained into age-related hearing loss

Oct 14, 2010

Researchers at the University of Minnesota Medical School have gained insight into how different types of age-related hearing loss may occur in humans. The discovery could eventually help physicians develop drugs to combat progressive hearing loss. Their paper is published on October 14 in the open-access journal PLoS Genetics.

James Ervasti, Ph.D., and colleague Ben Perrin, Ph.D., studied how two very closely related genes contribute to hearing function in mice. Mutations in the same genes are associated with deafness in humans. The duo discovered two key cellular processes that are required to maintain auditory function.

The encode proteins called β-actin and γ-actin. In humans, deafness-causing mutations have been linked to both proteins. β- and γ-actin comprise the primary structural elements of stereocilia (hair-like fibers in the ear), which convert mechanical sound energy into the nerve signals that allow humans to hear.

The two proteins are 99 percent identical; however, their slight differences have been exactly conserved through evolution from birds to mammals, suggesting that each protein may have important and distinct functions. Ervasti and Perrin tested the idea that two closely linked proteins have separate, but important, roles in hearing by knocking out each gene in mouse auditory hair cells.

They found that β-actin and γ-actin do have different maintenance functions that together keep the hair-like fibers -- that allow mice to hear -- healthy. Both knockout mice had normal hearing at young ages, but developed specific types of progressive and stereocilia pathology that differed depending on which protein was lost.

"These separate maintenance pathways are likely important for maintaining auditory function during aging and may contribute to future understanding of common forms of age-related hearing loss in humans," Perrin said.

Explore further: Genetic testing in kids is fraught with complications

More information: Perrin BJ, Sonnemann KJ, Ervasti JM (2010) b-Actin and c-Actin Are Each Dispensable for Auditory Hair Cell Development But Required for Stereocilia Maintenance. PLoS Genet 6(10): e1001158. doi:10.1371/journal.pgen.1001158

Related Stories

New mouse mutant contains clue to progressive hearing loss

Oct 31, 2008

Researchers have defined a mutation in the mouse genome that mimics progressive hearing loss in humans. A team from the Wellcome Trust Sanger Institute in Cambridge, UK, working with colleagues in Munich and Padua, found ...

Scientists identify genetic cause for type of deafness

Sep 03, 2009

A team led by scientists from The Scripps Research Institute has discovered a genetic cause of progressive hearing loss. The findings will help scientists better understand the nature of age-related decline in hearing and ...

Scaling the wall of deafness

Apr 14, 2009

Despite modern medicine, one in 1,000 American babies are born deaf. The numbers increase markedly with age, with more than 50% of seniors in the United States experiencing some form of hearing loss.

Researchers develop mouse model for muscle disease

Sep 05, 2006

Researchers from the University of Minnesota have identified the importance of a gene critical to normal muscle function, resulting in a new mouse model for a poorly understood muscle disease in humans.

Recommended for you

Genetic testing in kids is fraught with complications

Jul 02, 2015

A woman coping with the burden of familial breast cancer can't help but wonder if her young daughter will suffer the same fate. Has she inherited the same disease-causing mutation? Is it best to be prepared ...

Cause of acute liver failure in young children discovered

Jul 02, 2015

Acute liver failure is a rare yet life-threatening disease for young children. It often occurs extremely rapidly, for example, when a child has a fever. Yet in around 50 percent of cases it is unclear as to why this happens. ...

Genome sequencing illuminates rare Aicardi syndrome

Jul 02, 2015

As my inbox fills with ever more updates on the number of human genomes sequenced and the plummeting time and cost of next next next generation sequencing, I find myself hitting delete more and more often. ...

User comments : 0

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.