U.S. and Swiss scientists have made a breakthrough in understanding how a type of white blood cell called the eosinophil may help the body to fight bacterial infections in the digestive tract, according to research published online this week in Nature Medicine.
Hans-Uwe Simon, from the University of Bern, Switzerland, Gerald J.Gleich, M.D., from the University of Utah School of Medicine, and their colleagues discovered that bacteria can activate eosinophils to release mitochondrial DNA in a catapult-like fashion to create a net that captures and kills bacteria.
"This is a fascinating finding," says Gleich, professor of dermatology and internal medicine at the University of Utah and a co-author of the study. "The DNA is released out of the cell in less than a second."
Eosiniphils, which comprise only 1 to 3 percent of human white blood cells, are known to be useful in the body's defense mechanisms against parasites. But their exact role in the immune system is not clear. Unlike other white blood cells, which are distributed throughout the body, eosinophils are found only in selected areas, including the digestive tract. Mitochondria – often referred to as the power plants of the cell – are components within cells that are thought to descend from ancient bacteria. Although most cellular DNA is contained in the nucleus, mitochondria have their own DNA.
Previous research has shown that eosinophils secrete toxic granule proteins during parasite infections and that these granule proteins kill bacteria. Simon, Gleich, and their colleagues found that when eosinophils are stimulated by infection, such as E. coli, they rapidly secrete mitochondrial DNA. This DNA binds to the granule proteins and forms a net that is able to trap and kill bacteria. The researchers also found higher levels of eosinophils were linked to improved survival and lower numbers of bacteria in the blood of mice with widespread bacterial infections.
The toxic proteins released by eosinophils are not always helpful to the body, however, and can damage nearby tissues. The inflammation in some types of asthma and Crohn's disease, a chronic inflammatory disease of the bowel, is attributed to eosinophils. In fact, Simon and his team first found evidence of these DNA-protein traps in tissue taken from the digestive tracts of people with Crohn's disease.
Earlier studies suggested another type of white blood cell – the neutrophil – also expels DNA and granule proteins to kill bacteria. However, this DNA comes from the nucleus and its release causes the neutrophil to die. The eosinophil is able to survive after expelling its mitochondrial DNA.
The researchers hope to learn more about how eosiniphils expel mitochondrial DNA. They speculate that the explosive mechanism might rely on stored energy, similar to the way plants release pollen into the air. "We don't know how eosinophils are capable of catapulting mitochondrial DNA so quickly," says Gleich.
Future investigation may focus on how this energy is generated and how this new knowledge can be applied to the treatment of bacterial infections and inflammatory diseases related to eosinophils.
Gerald J. Gleich | EurekAlert!
Fingerprint' technique spots frog populations at risk from pollution
27.03.2017 | Lancaster University
Parallel computation provides deeper insight into brain function
27.03.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
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...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
27.03.2017 | Earth Sciences
27.03.2017 | Life Sciences
27.03.2017 | Life Sciences