Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tuning into cell signals that tell where sensory organs will form inside the ear

30.08.2010
These signals disappear early in life, but perhaps could be recharged to restore hearing loss in adults

Researchers have tracked a cell-to-cell signaling pathway that designates the future location of the ear's sensory organs in embryonic mice. The scientists succeeded in activating this signal more widely across the embryonic tissue that becomes the inner ear. Patches of sensory structures began growing in spots where they don't normally appear.

The structures contained tufted cells, called hair cells, which respond to sound waves and other sensations, and additional nerve cells that amplify or code sounds for the brain to interpret.

The results suggest an avenue for further investigation in restoring hearing loss from nerve damage.

The findings are reported this week in the early online edition of Proceedings of the National Academy of Sciences by researchers Byron H. Hartman, Thomas Reh, and Olivia Bermingham- McDonogh of the Department of Biological Structure at the University of Washington (UW) in Seattle. All three are members of the UW Institute for Stem Cells and Regenerative Medicine. The senior author, Bermingham-McDonogh, is also an affiliate of the UW Virginia Merrill Bloedel Hearing Research Center.

"As the population ages," said Bermingham-McDonogh, "there's a great interest in discovering how to regenerate the inner ear sensory cells that we need for our hearing and balance. Both of these falter as we get older -- we get hard of hearing and unsteady on our feet -- due to accumulated destruction of the sensory cells in the inner ear."

The goal of their research is to develop ways to restore inner ear sensory hair cells in people who have lost them due to age, excessive noise or other toxic damage. The hair cells do not spontaneously recover after they are lost, and adult stem cells have not been found in the mammalian inner ear. In order to devise a way to restart hair cell formation in the adult ear, Bermingham-McDonogh's group is studying how hair cells are made in the first place during ear development.

The first stage in the normal development of hair cells is called prosensory specification. In the growing embryo, regions of the ear-forming tissue are selected to become the inner ear organs that detect sound and allow for our sense of balance. This action is similar to digging the foundation of a building. All the subsequent, complex steps in the construction of the building require a solid foundation.

Byron Hartman, a postdoctoral fellow in the Bermingham-McDonogh lab, found that a signaling system called the Notch pathway is important in laying the foundation for the inner ear sensory hair cells and their associated supporting cells. The researchers were able to activate the Notch pathway in regions of the inner ear that would normally never make hair cells and convert these regions to patches of new sensory tissue. In other words, they could encourage the formation of new building foundations throughout the inner ear. Once these new sensory patches were made, new hair cells and support cells were properly produced within them. So by starting the ball rolling with the Notch signal, the researchers observed that the rest of the developmental processes followed along correctly.

Notch proteins straddle the inside and outside of the cell membrane. They collect information at the cell surface and report to the cell's operations center, the nucleus. Embryologists and cancer researchers have been studying the Notch pathway for many years. More recently scientists in the regenerative medicine field have begun taking advantage of this key regulatory signal to restart developmental processes in adults.

"The Notch signaling for prosensory specification does not appear to be active in the mature inner ear," the UW researchers noted, "and this could explain their lack of ability to regenerate new hair cells." They are now studying ways of manipulating the Notch pathway in the adult inner ear to see if this will stimulate hair cell regeneration in the hearing and balance organs.

If ways could be found to safely re-start particular Notch signals in adults, therapies might be designed to regenerate specific tissues, like nerves, and thereby repair damage and restore lost function, like hearing. Perhaps this knowledge, they noted, may lead to ideas on how to re-create this earlier state in the mature adult ear to stimulate re-growth of the cells critical to hearing.

The research for "Notch signaling specifies processor domains via lateral induction of the developing mammal inner ear" was supported by a National Research Service Award and grants from the National Institute on Deafness and Other Communication and National Eye Institute, both part of the National Institutes of Health, and assistance from the Lynn and Mike Garvey Cell Imaging Laboratory at the UW Institute for Stem Cell and Regenerative Medicine Research.

Leila Gray | EurekAlert!
Further information:
http://www.washington.edu

More articles from Life Sciences:

nachricht Immune Defense Without Collateral Damage
23.01.2017 | Universität Basel

nachricht The interactome of infected neural cells reveals new therapeutic targets for Zika
23.01.2017 | D'Or Institute for Research and Education

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>