Featured Research

from universities, journals, and other organizations

Gamma interferon a wake-up call for stem cell response to infection

Date:
June 11, 2010
Source:
Baylor College of Medicine
Summary:
Most of the time, the body's blood-forming stem cells remain dormant, with just a few producing blood cells and maintaining a balance among the different types. However, invading bacteria can be a call-to-arms, awaking the sleeping stem cells and prompting them to produce immune system cells. The "bugler" that awakes them is gamma interferon, a front-line protein defender against bacterial infection, researchers have found.

Most of the time, the body's blood-forming (hematopoietic) stem cells remain dormant, with just a few producing blood cells and maintaining a balance among the different types.

However, invading bacteria can be a call-to-arms, awaking the sleeping stem cells and prompting them to produce immune system cells that fight the foreign organisms. The "bugler" that awakes the stem cells in this battle is gamma interferon, a front-line protein defender against bacterial infection, said researchers from Baylor College of Medicine in a report that appears in the current issue of the journal Nature.

"We are looking at the normal function of stem cells," said Dr. Margaret Goodell, professor of molecular and human genetics at BCM and director of the Stem Cells and Regenerative Medicine (STaR) Center. She is the report's senior author. "One of those is to respond to an infection."

Goodell and her colleagues knew that cells farther along in the differentiation process responded to infection, increasing the production of immune cells.

"We were sure there was a mechanism by which hematopoietic stem cells respond to infection, but it was not obvious," she said. They started their work with gamma interferon because they knew it played an important role in bacterial infection.

The collaboration and talents of two researchers in her laboratory -- first co-authors Drs. Megan T. Baldridge and Katherine Y. King -- facilitated the work with mice that led to this finding, said Goodell. Both are at BCM.

"I think our findings represent an exciting new avenue for studying hematopoiesis," said King. "By viewing the hematopoietic stem cell as the source of the immune system, we are finding fundamental ways in which the immune response affects bone marrow. This is the first time that anyone has extensively studied hematopoietic stem cells in the context of an in vivo model (a living organism) of infection."

"As a specialist in infectious diseases, I see many patients whose bone marrow no longer produces sufficient blood cells as a consequence of their infection. This is particularly relevant in chronic infections such as mycobacterial diseases (that include tuberculosis) and AIDS," said King. "Our studies lend insight into the causes of this decrease in bone marrow function during such infections, and I hope the work will someday lead to new therapies."

Studies in mice with a chronic or long-term infection called Mycobacterium avium show that a greater proportion of a particular subset of their cells called long-term hematopoietic (blood-forming) stem cells are active. Gamma interferon prompts this activity. Mice that lack gamma interferon have fewer of these stem cells active during infection.

These findings show that gamma interferon not only activates stem cells during infection, but also regulate stem cells in normal times, enabling them to maintain the types of blood cells that exist in proportion or homeostasis.

"Our model predicts that bacterial infection detected by sentinel immune cells stimulates the increased release of gamma interferon, which then travels through the blood stream to activate HSCs (hematopoietic stem cells) in the bone marrow, leading to expansion and mobilization of the immune progenitor pool (the cells that ultimately produce immune system cells)," the researchers wrote.

They found that sustained activity by the hematopoietic stem cells can lead to at least transient problems with the quality of the stem cells and their abilities to stimulate production of more immune system cells.

"One of the most important things we found is the chronic infections (such as tuberculosis or HIV/AIDS) may be lead to bone marrow exhaustion," said Baldridge. "We knew that a condition called anemia of chronic disease exists, and this could be one of the contributing factors."

Funding for this work came from the National Institute of Diabetes and Digestive and Kidney Diseases, the Adeline B. Landa Fellowship of the Texas Children's Hospital Auxiliary, the Simmons Foundation Collaborative Research Fund, the National Heart, Lung and Blood Institute and the National Institute of Biomedical Imaging and Bioengineering.


Story Source:

The above story is based on materials provided by Baylor College of Medicine. Note: Materials may be edited for content and length.


Journal Reference:

  1. Megan T. Baldridge, Katherine Y. King, Nathan C. Boles, David C. Weksberg, Margaret A. Goodell. Quiescent haematopoietic stem cells are activated by IFN-γ in response to chronic infection. Nature, 2010; 465 (7299): 793 DOI: 10.1038/nature09135

Cite This Page:

Baylor College of Medicine. "Gamma interferon a wake-up call for stem cell response to infection." ScienceDaily. ScienceDaily, 11 June 2010. <www.sciencedaily.com/releases/2010/06/100609083231.htm>.
Baylor College of Medicine. (2010, June 11). Gamma interferon a wake-up call for stem cell response to infection. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2010/06/100609083231.htm
Baylor College of Medicine. "Gamma interferon a wake-up call for stem cell response to infection." ScienceDaily. www.sciencedaily.com/releases/2010/06/100609083231.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) 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