Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

09.06.2010
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 (www.bcm.edu) in a report that appears in the current issue of the journal Nature (www.nature.com).

"We are looking at the normal function of stem cells," said Dr. Margaret Goodell (www.bcm.edu/star/index.cfm?pmid=2947), professor of molecular and human genetics at BCM and director of the Stem Cells and Regenerative Medicine (STaR) (www.bcm.edu/star/index.cfm?PMID=0) 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 (www.niddk.nih.gov/), the Adeline B. Landa Fellowship of the Texas Children's Hospital Auxiliary, the Simmons Foundation Collaborative Research Fund (http://collaborativeresearchfund.org/), the National Heart, Lung and Blood Institute (www.nhlbi.nih.gov/) and the National Institute of Biomedical Imaging and Bioengineering (www.nibib.nih.gov/).

Glenna Picton | EurekAlert!
Further information:
http://www.bcm.edu
http://www.nature.com

More articles from Life Sciences:

nachricht Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel

nachricht Carcinogenic soot particles from GDI engines
24.05.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

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 quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>