Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Immune cells from patients with rheumatoid arthritis have prematurely aged chromosomes

06.03.2009
Telomeres, structures that cap the ends of cells' chromosomes, grow shorter with each round of cell division unless a specialized enzyme replenishes them. Maintaining telomeres is thought to be important for healthy aging and cancer prevention.

By this measure, T cells, or white blood cells, from patients with the autoimmune disease rheumatoid arthritis are worn out and prematurely aged, scientists at Emory University School of Medicine have discovered.

Compared with cells from healthy people, T cells from patients with rheumatoid arthritis have trouble turning on the enzyme that replenishes telomeres, they found. Reversing this defect could possibly help people prone to the disease maintain a balanced immune system.

The results are published online this week in Proceedings of the National Academy of Sciences.

In rheumatoid arthritis, T cells are chronically over-stimulated, invading the tissue of the joints and causing painful inflammation. This derangement can be seen as a result of the loss of the immune system's ability to discriminate friend from foe, says senior author Cornelia Weyand, MD, PhD, co-director of the Kathleen B. and Mason I. Lowance Center for Human Immunology at Emory University.

In childhood, new T cells are continually produced in the thymus, she says. But after about age 40, the thymus "involutes" – or shrinks and ceases to function. After that, the immune system has to make do with the pool of T cells it already has.

"What we see in rheumatoid arthritis is an aged and more restricted T cell repertoire," she says. "This biases the immune system toward autoimmunity."

Weyand, postdoctoral fellow Hiroshi Fujii, MD, PhD, and their colleagues were interested in mechanisms of T cells' premature aging, because scientists had previously observed that in rheumatoid arthritis, T cells tend to shift the molecules on their surface and function differently.

They found the answer in telomerase, the enzyme that renews telomeres and is necessary to prevent loss of genetic information after repeated cell division.

Telomerase adds short repeated DNA sequences to the ends of chromosomes to protect them. The enzyme is active in embryonic development but is usually switched off in adult cells. Many cancer cells reactivate it to enable runaway growth.

T cells are some of the very few cells in adults that can turn on telomerase when stimulated, probably because they have to divide many times and stay alive for decades.

Weyand and Fujii found that T cells from patients with rheumatoid arthritis make 40 percent less telomerase enzyme when stimulated. The cells came from 69 patients, 92 percent female, with an average age of 50, and were compared with cells from healthy people with similar demographics.

Shutting off a gene encoding part of the enzyme made normal T cells vulnerable to programmed cell death, and transferring telomerase into patients' T cells rescued them from dying.

The finding suggests that restoring defective telomerase to T cells could possibly help "reset" the immune system in rheumatoid arthritis, Weyand says.

Pharmaceutical industry researchers have been looking for drugs that could elevate or depress telomerase activity, with the goal of either prolonging life or treating cancer. However, turning on telomerase indiscriminately could lead to cancer, so any treatment would have to be targeted to the right cells, she says.

Holly Korschun | EurekAlert!
Further information:
http://www.emory.edu
http://www.pnas.org/cgi/doi/10.1073/pnas.0811332106

More articles from Life Sciences:

nachricht Research team of the HAW Hamburg reanimated ancestral microbe from the depth of the earth
01.03.2017 | Hochschule für Angewandte Wissenschaften Hamburg

nachricht Researchers Imitate Molecular Crowding in Cells
01.03.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

A better way to measure the stiffness of cancer cells

01.03.2017 | Health and Medicine

Exploring the mysteries of supercooled water

01.03.2017 | Physics and Astronomy

Research team of the HAW Hamburg reanimated ancestral microbe from the depth of the earth

01.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>