Freiburg researchers discover a molecule that smuggles toxins from intestinal pathogens into human cells
Prof. Dr. Dr. Klaus Aktories and Dr. Panagiotis Papatheodorou from the Institute of Experimental and Clinical Pharmacology and Toxicology of the University of Freiburg have discovered the receptor responsible for smuggling the toxin of the bacterium Clostridium perfringens into the cell.
The TpeL toxin is formed by C. perfringens, a pathogen that causes gas gangrene and food poisoning. It is very similar to the toxins of many other hospital germs of the genus Clostridium. The toxins bind to surface molecules and creep into the body cell, where they lead to cell death.
“In order to prevent the toxin from entering the cell, it is necessary to find the receptor that serves as the gatekeeper. But the search for this key molecule remained unsuccessful for a long time,” says Aktories, member of the Cluster of Excellence BIOSS Centre for Biological Signalling Studies. In cooperation with colleagues from Düsseldorf, the USA, and the Netherlands, the researchers from Freiburg have now identified a receptor for a clostridial toxin of this type for the first time ever.
Their findings were published in the journal Proceedings of the National Academy of Sciences (PNAS).
Clostridia cause intestinal and wound diseases in humans and animals that are often fatal. “At the moment, infections with the bacterium Clostridium difficile are particularly problematic in hospitals. The diseases tend to appear following treatment with antibiotics and often lead to diarrhea, but also to fatal inflammations of the bowels,” explains Aktories.
The toxins force their way into host cells and deactivate signaling molecules by attaching a sugar molecule to these cellular switches. Once this signaling pathway has been switched off, the cell dies – infested tissue dies off.
In order to find the receptor, the researchers applied a genetic selection procedure, a so-called screening, in which individual genes in cells from human cancer cell lines are turned off at random. This procedure led to the discovery that cells are immune to the TpeL toxin when the gene for the protein LRP1 is switched off on the cell surface.
LRP1, which stands for low density lipoprotein receptor-related protein 1, usually takes in proteins that serve as a means of transport for lipids in the blood. The researchers demonstrate that LRP1 is the long sought-after key molecule: It also regulates the intake of the toxin TpeL.
His team also proposes a new model, explains Aktories: “Our findings indicate that two receptors are involved in the effect of the other sugar-carrying clostridial toxins.” Researchers can use the findings to develop new agents against clostridia. “Our discovery will also provide new impetus for researchers to identify further toxin receptors,” Aktories hopes.
LRP1 is a receptor for Clostridium perfringens TpeL toxin indicating a two-receptor model of clostridial glycosylating toxins. Björn Schorch, Shuo Song, Ferdy R. van Diemen, Hans H. Bock, Petra May, Joachim Herz, Thijn R. Brummelkamp, Panagiotis Papatheodorou, and Klaus Aktories. PNAS 2014; published ahead of print April 15, 2014, doi:10.1073/pnas.1323790111
Prof. Dr. Dr. Klaus Aktories
Institute of Experimental and Clinical Pharmacology and Toxicology
University of Freiburg
Phone: +49 (0)761/203-5308
Prof. Dr. Dr. Klaus Aktories | University of Freiburg
Tiny songbird discovered to migrate non-stop, 1,500 miles over the Atlantic
01.04.2015 | University of Massachusetts at Amherst
The 'intraterrestrials': New viruses discovered in ocean depths
01.04.2015 | National Science Foundation
Spring is here and ectotherms, or animals dependent on external sources to raise their body temperature, are becoming more active. Recent studies have shown...
Glass-fronted office buildings are some of the biggest energy consumers, and regulating their temperature is a big job. Now a façade element developed by Fraunhofer researchers and designers for glass fronts is to reduce energy consumption by harnessing solar thermal energy. A demonstrator version will be on display at Hannover Messe.
In Germany, buildings account for almost 40 percent of all energy usage. Heating, cooling and ventilating homes, offices and public spaces is expensive – and...
Outstanding chemical, thermal and tribological properties predestine silicon carbide for the production of ceramic components of high volume. A novel method now overcomes the procedural and technical limitations of conventional design methods for the production of components with large differences in wall thickness and demanding undercuts.
Extremely hard as diamond, shrinking-free manufacturing, resistance to chemicals, wear and temperatures up to 1300 °C: Silicon carbide (SiSiC) bundles all...
In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...
The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.
As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...
25.03.2015 | Event News
19.03.2015 | Event News
17.03.2015 | Event News
01.04.2015 | Earth Sciences
01.04.2015 | Information Technology
01.04.2015 | Physics and Astronomy