Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Proteins Hey1 and Hey2 Ensure that Inner Ear 'Hair Cells' Are Made at the Right Time and in the Right Place

17.09.2014

Two Johns Hopkins neuroscientists have discovered the “molecular brakes” that time the generation of important cells in the inner ear cochleas of mice. These “hair cells” translate sound waves into electrical signals that are carried to the brain and are interpreted as sounds. If the arrangement of the cells is disordered, hearing is impaired. A summary of the research will be published in The Journal of Neuroscience on Sept. 16.

“The proteins Hey1 and Hey2 act as brakes to prevent hair cell generation until the time is right,” says Angelika Doetzlhofer, Ph.D., an assistant professor of neuroscience. “Without them, the hair cells end up disorganized and dysfunctional.”


Angelika Doetzlhofer

The hair cells of mice missing just Hey2 are neatly lined up in four rows (left) while those missing Hey1 and Hey2 are disorganized (right). The cells' hairlike protrusions (pink) can be misoriented, too.

The cochlea is a coiled, fluid-filled structure bordered by a flexible membrane that vibrates when sound waves hit it. This vibration is passed through the fluid in the cochlea and sensed by specialized hair cells that line the tissue in four precise rows. Their name comes from the cells’ hairlike protrusions that detect movement of the cochlear fluid and create electrical signals that relay the sound to the brain.

During development, “parent cells” within the cochlea gradually differentiate into hair cells in a precise sequence, starting with the cells at the base of the cochlea and progressing toward its tip. The signaling protein Sonic Hedgehog was known to be released by nearby nerve cells in a time- and space-dependent pattern that matches that of hair cell differentiation. But the mechanism of Sonic Hedgehog’s action was unclear.

Doetzlhofer and postdoctoral fellow Ana Benito Gonzalez bred mice whose inner ear cells were missing Hey1 and Hey2, two genes known to be active in the parent cells but turned off in hair cells. They found that, without those genes, the cells were generated too early and were abnormally patterned: Rows of hair cells were either too many or too few, and their hairlike protrusions were often deformed and pointing in the wrong direction.

“While these mice didn’t live long enough for us to test their hearing, we know from other studies that mice with disorganized hair cell patterns have serious hearing problems,” says Doetzlhofer.

Further experiments demonstrated the role of Sonic Hedgehog in regulating the two key genes.

“Hey1 and Hey2 stop the parent cells from turning into hair cells until the time is right,” explains Doetzlhofer. “Sonic Hedgehog applies those ‘brakes,’ then slowly releases pressure on them as the cochlea develops. If the brakes stop working, the hair cells are generated too early and end up misaligned.”

She adds that Sonic Hedgehog, Hey1 and Hey2 are found in many other parent cell types throughout the developing nervous system and may play similar roles in timing the generation of other cell types.

This work was supported by grants from the Whitehall Foundation (2010-05-81) and the National Institute on Deafness and other Communication Disorders (F32DC013477, DC005211).

On the Web:

View the article at The Journal of Neuroscience (after the embargo lifts). http://dx.doi.org/10.1523/JNEUROSCI.1494-14.2014

Learn more about Angelika Doetzlhofer.
www.hopkinsmedicine.org/profiles/results/directory/profile/6477655/angelika-doetzlhofer

Catherine Kolf | newswise

Further reports about: Cells Communication Disorders Medicine brakes cell types genes hair cells hearing sound waves

More articles from Life Sciences:

nachricht MicroRNA helps cancer evade immune system
19.09.2017 | Salk Institute

nachricht Ruby: Jacobs University scientists are collaborating in the development of a new type of chocolate
18.09.2017 | Jacobs University Bremen gGmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

Im Focus: Artificial Enzymes for Hydrogen Conversion

Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.

Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

New quantum phenomena in graphene superlattices

19.09.2017 | Physics and Astronomy

A simple additive to improve film quality

19.09.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>