Featured Research

from universities, journals, and other organizations

New Growth-stimulating Cue Identified For Nerve Cells

Date:
July 24, 2003
Source:
Johns Hopkins Medical Institutions
Summary:
For decades, scientists have hunted for signals that guide nerve cells' tentacle-like axons, hoping to understand how these cell tips reach out to distant targets. It's knowledge that might one day help researchers learn how to rebuild nerves lost to spinal cord injuries or diseases like Huntington's.

For decades, scientists have hunted for signals that guide nerve cells' tentacle-like axons, hoping to understand how these cell tips reach out to distant targets. It's knowledge that might one day help researchers learn how to rebuild nerves lost to spinal cord injuries or diseases like Huntington's.

Now, a Johns Hopkins team studying a family of proteins best known for repelling axons and inhibiting their growth reports finding one member that unexpectedly promotes axon growth instead. In their experiments, rat nerves in the lab grew more and longer axons on the side nearest a source of this protein, called semaphorin-7a. Moreover, in mice without semaphorin-7a, axons of some odor-sensing nerve cells never reached their targets, the scientists report in the July 24 issue of Nature.

"I've been studying semaphorins for about a decade and didn't expect to find any that stimulated axon growth, certainly not to the extent we saw in the lab and in mice," says Alex Kolodkin, Ph.D., professor of neuroscience in The Johns Hopkins University School of Medicine's Institute for Basic Biomedical Sciences. "Now we need to figure out how semaphorins balance their repulsive and attractive effects."

Part of the answer to this paradox, Kolodkin says, is that semaphorin-7a interacts with different proteins than its relatives. In experiments with rat nerve cells involved in sensing odors, first author and postdoctoral fellow Jeroen Pasterkamp, Ph.D., found that semaphorin-7a spurs axon growth by hooking onto proteins called integrins, which are found on nerves and many other cell types.

Among their many roles, integrins (pronounced IN-teh-grins) help control cells' interactions with their surroundings by capturing chemical signals and conveying the messages to cells' internal machinery. Even though this is the first report to link semaphorins and integrins, both protein families are rapidly being recognized as major contributors to neurological function and disease, says Kolodkin.

"Because integrins are important throughout the body, targeting them to stimulate axon growth or re-growth in a particular area of the brain or spinal cord presents many problems," notes Pasterkamp. "Our next steps are to find out exactly how semaphorin-7a's message is passed along inside the nerve, which will hopefully reveal a useful, specific target for promoting axon growth following nerve injury or degeneration."

As the researchers learn more of the specifics about how semaphorin-7a differs from its relatives, they also hope to redraw their picture of how semaphorins as a family affect nerve development throughout life, they say.

The research was funded by the Kirsch Foundation, the National Institute of Neurological Disease and Stroke (part of the National Institutes of Health), the Netherlands Organization for Scientific Research and the Human Frontier Science Program.

Authors on the paper are Pasterkamp and Kolodkin of Johns Hopkins, and Jacques Peschon and Melanie Spriggs of Amgen Corporation, Seattle, Wash.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "New Growth-stimulating Cue Identified For Nerve Cells." ScienceDaily. ScienceDaily, 24 July 2003. <www.sciencedaily.com/releases/2003/07/030724082019.htm>.
Johns Hopkins Medical Institutions. (2003, July 24). New Growth-stimulating Cue Identified For Nerve Cells. ScienceDaily. Retrieved August 22, 2014 from www.sciencedaily.com/releases/2003/07/030724082019.htm
Johns Hopkins Medical Institutions. "New Growth-stimulating Cue Identified For Nerve Cells." ScienceDaily. www.sciencedaily.com/releases/2003/07/030724082019.htm (accessed August 22, 2014).

Share This




More Health & Medicine News

Friday, August 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
American Ebola Patients Released: What Cured Them?

American Ebola Patients Released: What Cured Them?

Newsy (Aug. 21, 2014) It's unclear whether the American Ebola patients' recoveries can be attributed to an experimental drug or early detection and good medical care. Video provided by Newsy
Powered by NewsLook.com
Lost Brain Cells To Blame For Sleep Problems Among Seniors

Lost Brain Cells To Blame For Sleep Problems Among Seniors

Newsy (Aug. 21, 2014) According to a new study, elderly people might have trouble sleeping because of the loss of a certain group of neurons in the brain. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins