Featured Research

from universities, journals, and other organizations

Enabling Nerve Regeneration Means Evicting The Cleanup Crew

Date:
March 4, 2007
Source:
Cell Press
Summary:
Macrophages are the immune cells that engulf and destroy the debris of damaged tissue to enable the healing process to begin. Their presence at the scene of damage is critical, but once their task is complete, it is just as critical that macrophages exit rapidly, ending the inflammatory process and making way for regrowth. In fact, the continued presence of macrophages could damage tissue, compromising repair.

Macrophages are the immune cells that engulf and destroy the debris of damaged tissue to enable the healing process to begin. Their presence at the scene of damage is critical, but once their task is complete, it is just as critical that macrophages exit rapidly, ending the inflammatory process and making way for regrowth. In fact, the continued presence of macrophages could damage tissue, compromising repair.

Related Articles


While researchers know a great deal about the molecular machinery that launches this cellular cleanup crew into action, little has been known about the just-as-critical exit process.

Now, researchers have identified a key process by which macrophages are cleared from sites of peripheral nerve injury. The scientists say their findings could also have implications for understanding the same fundamental mechanism in spinal cord injury, stroke and multiple sclerosis.

Samuel David and colleagues published their findings in the March 1, 2007 issue of the journal Neuron, published by Cell Press.

The researchers concentrated on a family of cell receptors known as Nogo receptors, already known to be present on nerve cells and to play a role in nerve growth. Specifically, David and colleagues explored the role of one such Nogo receptor, NgR1. Receptors such as NgR1 are protein switches that nestle in the membranes of cells, and which induce a cellular response when triggered by a specific chemical signal, or ligand.

In the researchers' experiments, they induced damage in the sciatic nerve in the thigh of rats and mice and analyzed the role of NgR1 in the repair process.

They found that macrophages showed the presence of NgR1 on their surface once they arrive at the injury site and began their cleanup. Further experiments revealed that as the healing nerve began to form the protein myelin--the insulating sheath around nerves--this receptor not only caused a reduction in the macrophages' binding to myelin, but also an outright repulsion from the forming myelin. In fact, when the researchers created nerve injury such that new myelin would not be formed, the macrophages continued to lurk around the injury site. The researchers' experiments also identified specific molecules on myelin that triggered such repulsion.

The findings could also apply to nerves other than peripheral nerves, because macrophages activated during stroke, multiple sclerosis injury, and spinal cord injury also express NgR1 on their surface, pointed out the researchers.

"Our discovery of this novel (to our knowledge) role for NgRs in mediating the efflux of macrophages from inflamed neural tissue via interactions with myelin could therefore have broader implications for the regulation of inflammatory responses not only in other peripheral nerve pathologies, but also in [central nervous system] inflammation such as in spinal cord injuries, stroke, and multiple sclerosis," they concluded.

The researchers include Elizabeth J. Fry and Samuel David of The McGill University Health Center in Montreal, Quebec, Canada; Carole Ho of Stanford University Medical Center in Stanford, CA and Genentech Inc. in South San Francisco, CA.

This work was supported by a grant from the Canadian Institutes of Health Research to S.D. E.J.F. was supported by a Multiple Sclerosis Society of Canada post-doctoral fellowship and an award from the McGill University Health Center and Department of Medicine. C.H. was supported by an NINDS KO8 Career Development NS048058 Award.

Fry et al.: "A Role for Nogo Receptor in Macrophage Clearance from Injured Peripheral Nerve." Publishing in Neuron 53, 649--662, March 1, 2007. DOI 10.1016/j.neuron.2007.02.009. http://www.neuron.org.


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Cite This Page:

Cell Press. "Enabling Nerve Regeneration Means Evicting The Cleanup Crew." ScienceDaily. ScienceDaily, 4 March 2007. <www.sciencedaily.com/releases/2007/02/070228123332.htm>.
Cell Press. (2007, March 4). Enabling Nerve Regeneration Means Evicting The Cleanup Crew. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2007/02/070228123332.htm
Cell Press. "Enabling Nerve Regeneration Means Evicting The Cleanup Crew." ScienceDaily. www.sciencedaily.com/releases/2007/02/070228123332.htm (accessed October 24, 2014).

Share This



More Mind & Brain News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Academic Scandal Shocks UNC

Academic Scandal Shocks UNC

AP (Oct. 23, 2014) A scandal involving bogus classes and inflated grades at the University of North Carolina was bigger than previously reported, a new investigation found. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Working Mother Getaway: Beaches Turks & Caicos

Working Mother Getaway: Beaches Turks & Caicos

Working Mother (Oct. 22, 2014) Feast your eyes on this gorgeous family-friendly resort. Video provided by Working Mother
Powered by NewsLook.com
What Your Favorite Color Says About You

What Your Favorite Color Says About You

Buzz60 (Oct. 22, 2014) We all have one color we love to wear, and believe it or not, your color preference may reveal some of your character traits. In celebration of National Color Day, Krystin Goodwin (@kyrstingoodwin) highlights what your favorite colors may say about you. Video provided by Buzz60
Powered by NewsLook.com
First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

Newsy (Oct. 21, 2014) A medical team has for the first time given a man the ability to walk again after transplanting cells from his brain onto his severed spinal cord. 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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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