Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research identifies promising route for treating age-related hearing loss

14.01.2005


Work should boost studies of hair-cell regeneration

Researchers have discovered that deletion of a specific gene permits the proliferation of new hair cells in the cochlea of the inner ear -- a finding that offers promise for treatment of age-related hearing loss. This type of hearing loss is caused by aging, disease, certain drugs, and the cacophony of modern life. It is the most common cause of hearing loss in older people.

The research team, which included Howard Hughes Medical Institute investigator David P. Corey, published their findings on January 13, 2005, in Science Express, which provides rapid electronic publication of selected Science publications. Zheng-Yi Chen, who is at Massachusetts General Hospital and Harvard Medical School, is the senior author of the article. He trained with Corey at Harvard Medical School. Other co-authors are from the University of Virginia School of Medicine, Tufts-New England Medical Center, and Northwestern University.



Hair cells in the cochlea detect sound by vibrating in response to sound waves, triggering nerve impulses that travel to the auditory region of the brain. Normally, humans are born with a complement of about 50,000 hair cells. But since the cells do not regenerate, the steady rate of hair-cell loss that can accompany aging produces significant hearing loss in about a third of the population by the time they reach 70-years-old.

Chen did a broad survey that examined patterns of gene expression during embryonic development of the balance organ of the inner ear. His results suggested that there might be a gene that produces a protein that acts as a permanent "brake" on hair-cell regeneration. That survey, which was done in mice, revealed that the retinoblastoma gene seemed to be particularly active during embryonic development.

At the same time, co-author Philip Hinds at Tufts-New England Medical Center had developed a knockout mouse lacking the retinoblastoma gene Rb1.

"He noticed that these mice ran in circles, and for an inner-ear biologist, a mouse running in circles immediately tells you that there is some problem with the vestibular system of the inner ear," said Corey. Thus, he said, Chen began a detailed study of the hair cells of the knockout mice. Those studies revealed that the mice without Rb1 had more hair cells than normal mice, and the cells were actively proliferating.

Corey and his colleagues then launched studies to determine whether the proliferating cells were, indeed, functional hair cells. They found that mechanically stimulating the cells generated an electrical signal characteristic of hair cells. Also, Corey and his colleagues found that the cells absorbed a fluorescent dye that only moves through the membrane channels of functional hair cells.

In further studies, Chen and his colleagues found that knocking out the Rb1 gene in cultured mature inner ear cells from mice triggered the cells to begin proliferating.

"This experiment demonstrated that it was a direct effect of the Rb gene and not some indirect effect during development that controlled proliferation of hair cells," said Corey. "So Zheng-Yi has found that deletion of this gene can allow functioning hair cells to continue to divide. They are no longer limited by whatever growth controls existed before. This work gives us an invaluable window into the control mechanism, which could lead to eventual clinical application in regenerating lost hair cells," said Corey.

According to Corey, the findings also have important implications for basic research. "A major obstacle to hair-cell research has been that, since there are not very many hair cells in the inner ear, it has been hard to get enough material for study," he said. "But with Zheng-Yi’s work, we now have the potential for generating cultured lines of hair cells for experiments."

"While we are very excited about the potential for hair-cell regeneration from this work, much basic research needs to be done," emphasized Corey. "Simply inactivating the Rb gene allows the hair cells to keep dividing and dividing, which might produce tumors in the inner ear. So, Zheng-Yi and his colleagues will be seeking ways to inactivate the gene only long enough to allow a clinically useful amount of proliferation, before turning the gene back on." The approach, he said, will require a greater understanding of the mechanisms controlling the Rb signaling pathway.

Jim Keeley | EurekAlert!
Further information:
http://www.hhmi.org

More articles from Life Sciences:

nachricht When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short
23.03.2017 | Institut für Pflanzenbiochemie

nachricht WPI team grows heart tissue on spinach leaves
23.03.2017 | Worcester Polytechnic Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>