Neutrophil granulocytes comprise important defences for the immune system. When pathogenic bacteria penetrate the body, they are the first on the scene to mobilise other immune cells via signal molecules, thereby containing the risk.
Microscope image of normal human bone marrow tissue with stained NSP4 in myeloblasts and myelocytes. © MPI of Neurobiology
To this end, they release serine proteases – enzymes that cut up other proteins to activate signal molecules. Scientists at the Max Planck Institute of Neurobiology in Martinsried have now discovered a new serine protease: neutrophil serine protease 4, or NSP4. This enzyme could provide a new target for the treatment of diseases that involve an overactive immune system, such as rheumatoid arthritis.
The functioning of the immune system is based on the complex interplay of the most diverse cells and mediators. For example, neutrophil granulocytes (a group of specialized white blood cells) react to bacteria by releasing substances called serine proteases. These enzymes are able to activate signal molecules, such as the chemokines, by cleaving them at a specific position on the molecule. The active signal molecules then guide other immune cells to the focus of inflammation in order to destroy the pathogens.
A research team led by Dieter Jenne at the Max Planck Institute of Neurobiology in Martinsried has come across a previously unknown protease in humans: neutrophil serine protease 4, or NSP4. "The special thing about this enzyme is that it cuts proteins that have the amino acid arginine at a particular point", says Dieter Jenne, research group leader at the Martinsried-based Institute. "This is where NSP4 differs from the other three known neutrophil serine proteases, which are similar in molecular structure, but have a different recognition motif." The scientists may be able to harness this difference to develop an active substance that specifically inhibits NSP4, thereby reducing the immune reaction.
However, serine protease activity comes at a cost. The enzymes not only heal inflammations, but sometimes cause them in the first place. If too many immune cells are activated, they can use their arsenal of aggressive chemical weapons against the body's own tissues. A number of chronic inflammatory diseases are based on precisely this effect. As a result, scientists are searching for substances that can block the neutrophil proteases. To date, however, none of the substances tested have been developed into effective drugs.
"So far, we don't know the identity of the NSP4 substrate, but we assume they must be signal molecules", says Dieter Jenne. Activated chemokines can recruit a vast number of neutrophils, and their sheer quantity alone is enough to cause tissue damage. "Proteases sometimes act as accelerants and can even trigger a chronic inflammation quite independently of bacterial intruders. If we dampened down the defences, we could counteract this effect", explains the scientist.
In terms of evolutionary history, NSP4 is the oldest of the four known neutrophil serine proteases. Using gene sequences, scientists have shown that the enzyme has hardly changed through hundreds of millions of years of evolution from bony fish to humans. "That would indicate that NSP4 regulates a fundamental process", says Dieter Jenne.
The fact that the enzyme remained undiscovered until now is because it occurs at a much lower concentration than the other three proteases. The Max Planck scientists came across it while searching the human genome for genes that encode serine proteases. In the process, they noticed a previously unknown gene sequence. Natascha C. Perera, a member of the Martinsried research group and lead author of the study, managed to produce and examine the enzyme in its active, folded state.
If they are to establish NSP4 in the future as a possible target protein for anti-inflammatory drugs, the scientists must now examine its function in living organisms and discover whether blocking the enzyme has adverse effects. The scientists are working with the company Novartis to answer these questions in laboratory mice. "NSP4 inhibitors could be used in diseases like chronic arthritis or inflammatory skin diseases", says Dieter Jenne, "but first we have to test the long-term effects of these substances."
ContactDr. Dieter Jenne
PNAS, April 2, 2012 DOI: 10.1073/pnas.1200470109
Dr. Dieter Jenne | EurekAlert!
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Power and Electrical Engineering
16.01.2017 | Information Technology
16.01.2017 | Power and Electrical Engineering