Researchers from the University of Basel in Switzerland have clarified the role of the enzyme MPO. In fighting infections, this enzyme, which gives pus its greenish color, produces a highly aggressive acid that can kill pathogens without damaging the surrounding tissue. The findings, published in the current issue of Nature Microbiology, may provide new approaches for immunity strengthening therapies.
In the human body’s fight against bacterial pathogens, white blood cells are in the front line. They identify and ingest the invaders, and render them harmless using highly toxic substances. It is important that these substances only destroy bacteria but cause as little collateral damage as possible to the surrounding tissue.
The research groups headed by Prof. Dirk Bumann from the Biozentrum and Dr. Nina Khanna from the Department of Biomedicine at the University and the University Hospital Basel discovered how white blood cells solve this difficult task.
The enzyme myeloperoxidase (MPO) attaches directly to the surface of the bacterium where it produces an extremely aggressive acid. The acid reacts instantly in the immediate environment, burning a hole into the bacterial cell envelope which kills the bacterium. In combating bacterial infections, the enzyme acts like a sniper: Equipped with highly explosive ammunition, it targets extremely precisely, without causing collateral damage to their surroundings.
The function of MPO – the greenish color in pus
White blood cells fight bacterial invaders by producing hydrogen peroxide – a toxic substance, which is generally known for its use in bleaching hair. The enzyme MPO then converts hydrogen peroxide into hypochlorous acid. This acid, which is highly aggressive, immediately reacts on the surface of the bacteria and kills the invader. “Bacteria are helpless against this acid bomb,” explains Dirk Bumann. “As hypochloric acid is so highly reactive, the bomb reacts immediately with the closest biomolecules. It is ignited locally and does not spread to the wider surroundings. The bacteria die and the surrounding tissue is spared.” These findings enabled the research team to elucidate the precise function of the enzyme MPO, which is responsible for the greenish color seen in pus.
Long-term effects of collateral damage have not been sufficiently investigated
In their study, the researchers also investigated cells from humans who lack the enzyme MPO due to a genetic defect. This defect affects around one in 5000 people, making it quite rare. In these individuals, the hydrogen peroxide is not converted into hypochlorous acid and accumulates until it leaks out into the blood cells as well as the surrounding tissue. “The bacteria are still killed even without MPO. However, not only the bacteria but also the blood cells and their surroundings are damaged,” explains Bumann. “The collateral damage of blood cells and tissues without MPO may cause long-term consequences such as accelerated aging and cancer, but this has not yet been systematically investigated,” adds Nina Khanna.
MPO – an enzyme with two faces
“As we are confronted by fewer infections today than in the past when MPO evolved, the collateral damage issue and its control by MPO might play less important roles,” says Khanna. On the other hand, it may be possible to develop new treatment strategies to fight bacterial infections, which support the immune response by strengthening the MPO mechanism. “Currently, only drugs that do the opposite and inhibit MPO are being developed. The reason is that MPO can have negative effects in the case of heart disease,” points out Dirk Bumann. However, if such MPO inhibitors were used broadly, patients with infections might suffer.
Nura Schürmann, Pascal Forrer, Olivier Casse, Jiagui Li, Boas Felmy, Anne-Valérie Burgener, Nikolaus Ehrenfeuchter, Wolf-Dietrich Hardt, Mike Recher, Christoph Hess, Astrid Tschan-Plessl, Nina Khanna, Dirk Bumann
Myeloperoxidase targets oxidative host attacks to Salmonella and prevents collateral tissue damage
Nature Microbiology (2017), doi: 10.1038/nmicrobiol.2016.268
Prof. Dr. Dirk Bumann, University of Basel, Biozentrum, Tel. +41 61 207 23 82, Email: email@example.com
Heike Sacher, University of Basel, Biozentrum, Communications, Tel. +41 61 207 14 49, Email: firstname.lastname@example.org
Heike Sacher | Universität Basel
Multifunctional Platform for the Delivery of Gene Therapeutics
22.01.2018 | Angewandte Chemie International Edition
Charge Order and Electron Localization in a Molecule-Based Solid
22.01.2018 | Max-Planck-Institut für Chemische Physik fester Stoffe
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
22.01.2018 | Life Sciences
22.01.2018 | Power and Electrical Engineering
22.01.2018 | Power and Electrical Engineering