Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Not even cell death can stop the alarm

23.06.2014

Even after a cell dies, components of the immune system remain active and continue to fuel inflammatory reactions.

An international team of researchers under the direction of scientists from the Institute of Innate Immunity at the University Hospital of Bonn has discovered how this incredible form of communication works.


Image of macrophages containing activated inflammasomes: redistribution of ASC molecules (green) to form ASC specks (green fibrillar structures). Nuclei are shown in blue and plasma membranes in red.

(c) Photo: Eicke Latz/Uni Bonn

The findings offer potentially novel approaches for therapies against many serious diseases that affect a large part of the population, such as gout, atherosclerosis and Alzheimer's disease. The exciting new results are now published in the renowned journal "Nature Immunology".

When there is stress in living immune cells, – for example due to the detection of microbes, or the deposition of uric acid crystals in joints, cholesterol in blood vessels or Alzheimer's plaques in the brain – the so-called ‘inflammasome’ sounds the alarm. Inflammasomes are large multiprotein complexes, which form when they sense cell stress.

The inflammasomes activate an enzyme, which stimulates important messengers that in turn trigger an inflammatory reaction. During this cell activation, the affected immune cells die and thus the inflammatory reaction should come to a halt. "This mechanism primarily protects the body from infections and harmful influences," says Prof. Eicke Latz, the director of the Institute of Innate Immunity at the University Hospital in Bonn.

Strikingly, these new findings reveal that inflammasomes remain active even when the cells have died. The scientists were able to demonstrate that activated inflammasomes also have enzymatic functions outside of the living cell and can thus activate additional messengers. In a type of chain reaction, the inflammasomes released from dying cells are taken up by neighboring immune cells where they can activate more inflammasomes.

This discovery was made by an international team of researchers under the direction of the members from the Institute of Innate Immunity, together with scientists from Hannover Medical School, the University of Massachusetts Medical School (USA), the German Center for Neurodegenerative Diseases (DZNE) in Bonn, the University of Trondheim (Norway), the University of Newcastle (Australia) and the Zurich University Hospital (Switzerland).

Protein complexes shift into defense mode

When the inflammasomes are switched on, within seconds they form functional protein complexes, which can be as large as a bacterium. "In the event of stress or infection, this protein complex forms and provokes the activation of pro-inflammatory messengers within the cell and – as we now know – this can also occur outside of the cell. In this way, there can be a very rapid inflammatory reaction which helps the undesired insult or microbial invaders to be eliminated as quickly as possible," explains lead author Dr. Bernardo S. Franklin, a fellow of the Alexander von Humboldt Foundation working in Prof. Latz's team.

Using fluorescence techniques, the researchers labeled the inflammasome in immune cells. Whenever it was active, it formed a fluorescent protein complex, reminiscent of small stars glowing inside the cell. Using this method, the scientists were able to track the inflammasome after cell death, and show that it remained switched on as an intact protein complex. They also found that once released from the dead cell, it stimulated neighboring cells to undergo an inflammatory reaction. Furthermore, they found that these extracellular complexes accumulate in the lungs of patients with chronic lung disease.

Starting points for new therapies against widespread diseases

"Normally, the immune system is very helpful for averting harmful damage to tissue by initiating an inflammatory reaction," says Prof. Latz. However, if such inflammatory reactions are excessive or if they persist for longer than necessary, this may contribute to common diseases of Western society, such as gout, Alzheimer's disease, diabetes or atherosclerosis. With the discovery of extracellular inflammasomes, the researchers have revealed an interesting avenue for potential new therapies: "If we are able to produce suitable antibodies, it is likely we could contain the alarm of the inflammasome outside of cells and thus keep harmful chronic inflammatory reactions at bay, without affecting the necessary response inside the cell" says Prof. Latz.

Publication: The adaptor ASC has extracellular and prionoid activities that propagate inflammation, "Nature Immunology", DOI: 10.1038/ni.2913

Contact information:

Prof. Dr. Eicke Latz
Institute of Innate Immunity
University Hospital of Bonn
Tel. 0228/28751223
E-Mail: eicke.latz@uni-bonn.de
Web: www.iii.uni-bonn.de

Johannes Seiler | idw - Informationsdienst Wissenschaft

Further reports about: activation death diseases immune inflammatory reaction therapies

More articles from Health and Medicine:

nachricht Real-time imaging of lung lesions during surgery helps localize tumors and improve precision
30.07.2015 | American Association for Thoracic Surgery

nachricht Experimental MERS vaccine shows promise in animal studies
29.07.2015 | NIH/National Institute of Allergy and Infectious Diseases

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

Im Focus: Smarter window materials can control light and energy

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...

Im Focus: Simulations lead to design of near-frictionless material

Argonne scientists used Mira to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Argonne Leadership Computing Facility (ALCF) researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.

While reviewing the simulation results of a promising new lubricant material, Argonne researcher Sanket Deshmukh stumbled upon a phenomenon that had never been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

Intracellular microlasers could allow precise labeling of a trillion individual cells

30.07.2015 | Life Sciences

Real-time imaging of lung lesions during surgery helps localize tumors and improve precision

30.07.2015 | Health and Medicine

New study exposes negative effects of climate change on Antarctic fish

30.07.2015 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>