Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chicken embryo research tunes into inner ear

03.09.2003


Purdue University biologists have learned how to control the development of stem cells in the inner ears of embryonic chickens, a discovery which could potentially improve the ability to treat human diseases that cause deafness and vertigo.


Figure 1 shows part of the cochlea in an embryonic chicken’s inner ear, where patches of vestibular hairs, used to detect balance, grew in place of those that detect sound waves. The arrow indicates one such patch. Figure 2 is a close-up that shows both types of inner-ear hairs, which grow in tufts in different locations. The inset shows the type that detects bodily motion, with the hairs themselves stained red and the telltale cilia that extend from motion-detecting tufts stained green.



By introducing new genes into the cell nuclei, researchers instructed the embryonic cells to develop into different adult cells than they would have ordinarily. Instead of forming the tiny hairs that the inner ear uses to detect sound waves, the stem cells matured into tissue with different kind of hairs – the sort used to keep balance. This ability to guide the choice of cell types could expand researchers’ knowledge of the inner ear and its disorders.

"We’ve essentially switched the fate of these cells," said Donna Fekete (pronounced FEH-ka-tee), associate professor of biology in Purdue’s School of Science. "We now know at least one gene that determines what these embryonic ear cells will eventually become. As a result, we can control the outcome ourselves using gene transduction. Because so many people suffer from deafness later in life, we hope this research will yield treatments for them down the line."


The research appears in the current (9/1) issue of Developmental Biology.

Fekete’s group stumbled onto these results after setting out to determine the function of a family of genes found in many embryonic cells. These genes, called "Wnt" genes, influence the development of organs from the brain to muscles, but they also seemed connected in some unknown capacity to the ear. Some evidence that pointed in this direction came from Fekete’s collaborators in England, who work in the lab of Julian Lewis.

"We knew the Wnt genes were present in the ears of embryonic chicks," Fekete said. "We thought that altering the genes would perturb ear development in some way, and from a pure research perspective we wanted to know what that perturbation was. So, just to see what would happen, we used a modified retrovirus to deliver a souped-up version of a gene to make more cells experience the Wnt signal."

Retroviruses are the Trojan horses of the gene therapy world – the infectious genetic material within their shells can be replaced with genes of the researcher’s choosing, which the retrovirus then delivers to the nucleus of the target cell. The technique, when used on the chick cells, caused them to develop into otherwise healthy tissue that ordinarily appeared in different places in the inner ear.

"The inner ear uses two kinds of tiny hairs to sense sound and bodily motion," Fekete said. "These hairs are microscopic, and they are very different than the hairs you have on your head. The two kinds of inner ear hairs are different in one obvious respect – both types grow in tufts, but those tufts used for balance also have single, long cilia that stretch out from among the hairs. After we turned the Wnt genes on, we saw these cilia growing in places usually reserved for the non-ciliated auditory hairs."

Many researchers overseas are trying to make stem cells develop into different types of adult cells in order to cure diseases, and Fekete said she believes this is the kind of information they will eventually need to help humans.

"More than half of the U.S. population over the age of 60 has some sort of hearing loss," she said. "These cases are often caused by degeneration of inner ear cells damaged over the long term. Many young people also lose their hearing from sudden acoustic trauma. If we are to replace the damaged cells, we will presumably need to know how to grow the right cell type."

Another problem this research could address is the set of disorders that cause vertigo, which includes Meniere’s disease. This disorder, which strikes approximately one person out of 2,000 annually, causes bouts of severe disequilibrium and tinnitus and lasts for life.

"An added benefit of this discovery is that it not only switches the type of surface cells responsible for hairs, it switches the type of supporting cells as well. In other words, we can make entire sections of the inner ear grow one way or the other, which might permit doctors more options."

It will, however, be many years before such therapies might be ready for human testing.

"There’s still a great deal of work to be done here," Fekete said. "We still are not sure what happens when you completely deactivate the Wnt signal, for example, and that’s where our research is headed next. In any case, a cure for deafness based on this discovery won’t be appearing in your drugstore anytime soon."

Fekete did say, however, that the research was yet another example of the potential of stem cell research.

"Even if we cannot do research on human stem cells, those taken from animals can still contribute to our understanding of how living things develop," she said. "It’s work that needs to continue."

This research was supported in part by the National Institutes of Health.

Writer: Chad Boutin, (765) 494-2081, cboutin@purdue.edu

Source: Donna Fekete, (765) 496-3058, dfekete@purdue.edu

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

Chad Boutin | Purdue News
Further information:
http://news.uns.purdue.edu/html4ever/030902.Fekete.ear.html
http://www.indygov.org/mayor/cilsi/

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>