Featured Research

from universities, journals, and other organizations

Possible trigger for multiple sclerosis nerve damage

Date:
November 27, 2012
Source:
NIH/National Institute of Neurological Disorders and Stroke
Summary:
High-resolution real-time images show in mice how nerves may be damaged during the earliest stages of multiple sclerosis. The results suggest that the critical step happens when fibrinogen, a blood-clotting protein, leaks into the central nervous system and activates immune cells called microglia.

Microglia (green cells) cluster around leaking blood vessels days before neurological damage occurs in a mouse model of MS.
Credit: Courtesy of Akassoglou lab, Gladstone Institute.

High-resolution real-time images show in mice how nerves may be damaged during the earliest stages of multiple sclerosis. The results suggest that the critical step happens when fibrinogen, a blood-clotting protein, leaks into the central nervous system and activates immune cells called microglia.

"We have shown that fibrinogen is the trigger," said Katerina Akassoglou, Ph.D., an associate investigator at the Gladstone Institute for Neurological Disease and professor of neurology at the University of California, San Francisco, and senior author of the paper published online in Nature Communications.

Multiple sclerosis, or MS, is thought to be an autoimmune disease in which cells that normally protect the body against infections attack nerve cells in the brain and spinal cord, often leading to problems with vision, muscle strength, balance and coordination, thinking and memory. Typically during MS, the immune cells destroy myelin, a protective sheath surrounding

nerves, and eventually leading to nerve damage. The immune attack also causes leaks in the blood-brain barrier, which normally separates the brain from potentially harmful substances in the blood.

"Dr. Akassoglou has focused on the role of the blood-brain barrier leak in MS and has discovered that leakage of the blood clotting protein fibrinogen can trigger brain inflammation," said Ursula Utz, Ph.D., M.B.A., a program director at NIH's National Institute of Neurological Disorders and Stroke (NINDS).

Microglia are cells traditionally thought to control immunity in the nervous system. Previous studies suggested that leakage of fibrinogen activates microglia. In this study, Dr. Akassoglou and her colleagues used a cutting-edge imaging technique called two-photon laser scanning microscopy to watch what happens in an animal model of MS.

"Our results provide the first evidence linking leakage of fibrinogen to neuronal damage," said Dr. Akassoglou, "Vascular changes are the instigator of neurotoxicity."

Using a mouse model of MS, the researchers found that leakage of fibrinogen and microglial activation occurred days before nerve damage began, suggesting they occur in an early, pre-clinical stage of the disease.

During this period, microglia changed shapes and clustered around blood vessels along with other immune cells. Further experiments suggested that fibrinogen activated microglia by binding to a receptor, called CD11b/CD18, which caused the microglia to release reactive oxygen molecules that, in turn, damaged neurons. Inhibiting the binding of fibrinogen to the receptor prevented microglial activation and nerve damage.

Current treatments for MS are designed to suppress autoimmunity. The results from this study suggest that targeting the interaction between fibrinogen and microglia may be an effective alternative. In the mice, blocking fibrinogen's blood clotting activity prevented microglial activation and nerve damage.

"Current drugs target primarily downstream events. This interaction could be an upstream target that suppresses immunity and neurodegeneration," said Dr. Akassoglou.

In 2006, Dr. Akassoglou received a Presidential Early Career Award for Scientists and Engineers, which honors and supports the finest and most promising researchers early in their careers.

This study was supported by NINDS (NS051470, NS052189, NS066361); the National Cancer Institute (CA082103); the National Center for Research Resources (RR004050), the National Heart, Lung, and Blood Institute (HL096126), the American Heart Association, the Bechtel Foundation, the Dana Program in Brain and Immuno-imaging, the H. Lundbeck A/S, the Howard Hughes Medical Institute, the National Multiple Sclerosis Society, the Nancy Davis Foundation for Multiple Sclerosis, and the March of Dimes.


Story Source:

The above story is based on materials provided by NIH/National Institute of Neurological Disorders and Stroke. Note: Materials may be edited for content and length.


Journal Reference:

  1. Dimitrios Davalos, Jae Kyu Ryu, Mario Merlini, Kim M. Baeten, Natacha Le Moan, Mark A. Petersen, Thomas J. Deerinck, Dimitri S. Smirnoff, Catherine Bedard, Hiroyuki Hakozaki, Sara Gonias Murray, Jennie B. Ling, Hans Lassmann, Jay L. Degen, Mark H. Ellisman, Katerina Akassoglou. Fibrinogen-induced perivascular microglial clustering is required for the development of axonal damage in neuroinflammation. Nature Communications, 2012; 3: 1227 DOI: 10.1038/ncomms2230

Cite This Page:

NIH/National Institute of Neurological Disorders and Stroke. "Possible trigger for multiple sclerosis nerve damage." ScienceDaily. ScienceDaily, 27 November 2012. <www.sciencedaily.com/releases/2012/11/121127154215.htm>.
NIH/National Institute of Neurological Disorders and Stroke. (2012, November 27). Possible trigger for multiple sclerosis nerve damage. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2012/11/121127154215.htm
NIH/National Institute of Neurological Disorders and Stroke. "Possible trigger for multiple sclerosis nerve damage." ScienceDaily. www.sciencedaily.com/releases/2012/11/121127154215.htm (accessed September 20, 2014).

Share This



More Health & Medicine News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Sierra Leone's Nationwide Ebola Curfew Underway

Sierra Leone's Nationwide Ebola Curfew Underway

Newsy (Sep. 20, 2014) Sierra Leone is locked down as aid workers and volunteers look for new cases of Ebola. Video provided by Newsy
Powered by NewsLook.com
Changes Found In Brain After One Dose Of Antidepressants

Changes Found In Brain After One Dose Of Antidepressants

Newsy (Sep. 19, 2014) A study suggest antidepressants can kick in much sooner than previously thought. Video provided by Newsy
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
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