Though researchers have known for over a century that red blood cells infected with malaria parasites can kill their host by sticking to the sides of blood vessels, the binding mechanism associated with the most lethal forms of malaria was unknown.
Now, in a study published in Nature, the researchers show that the parasite binds a protein in blood vessel walls called endothelial protein C (EPCR), which is involved with regulating blood coagulation and the inflammatory response.
Malaria parasites grow in red blood cells and stick to the endothelial lining of blood vessels through a large family of parasite proteins called PfEMP1. This way, the parasite avoids being carried with the blood to the spleen, where it would otherwise be destroyed. One of the most aggressive forms of malaria parasite binds in brain blood vessels, causing a disease called cerebral malaria. In 2012, three groups of researchers, including the teams at the University of Copenhagen and Seattle Biomedical Research Institute, showed that a specific type of PfEMP1 protein was responsible for cerebral binding and other severe forms of malaria infection. However, until now, the receptor to which it binds remained unknown, and the next big question was to determine which receptors the infected red blood cells were binding to.
“The first big challenge was to generate a full-length PfEMP1 protein in the laboratory,” says Assistant Professor Louise Turner at the University of Copenhagen. “Next, we utilized a new technology developed by Retrogenix LTD in the United Kingdom to examine which of over 2,500 human proteins this PfEMP1 protein could bind to.” Of the 2,500 proteins screened, a receptor called endothelial protein C (EPCR) was the single solid hit.
“A lot of work then went into confirming this binding in the lab and not least to show that parasites from non-immune children with severe malaria symptoms in Tanzania often bound EPCR,” she continues.
“It was a true eureka moment,” says Assistant Professor Thomas Lavstsen. “Under normal conditions, ECPR plays a crucial role in regulating blood clotting, inflammation, cell death and the permeability of blood vessels. The discovery that parasites bind and interfere with this receptor´s normal function may help us explain why severe symptoms of malaria develop."
“Investigating this question is the next step to learn about how malaria parasites cause disease.”Towards an intervention
“Now that we know the pair of proteins involved, we can begin zooming further in to reveal the molecular details of how malaria parasites grab onto the sides of blood vessels. We want to know exactly which bits of the parasite protein are needed to bind to the receptor in the blood vessel wall. Then, we can aim to design vaccines or drugs to prevent this binding.”
Vaccine research will also benefit immediately from the discovery, since scientists can already now test the effectiveness of different vaccine candidates at preventing PfEMP1 from binding ECPR. “Over the last decade, we have come to appreciate that specific PfEMP1 proteins are associated with different severe forms of malaria,” explains Professor Thor Theander at the University of Copenhagen. “Together with The National Institute for Medical Research Tanzania, we are in the process of preparing phase I trials for a vaccine to prevent parasite binding in the placenta and malaria during pregnancy,” he explains. This new discovery holds the potential for also developing a vaccine to reduce the heavy burden malaria disease inflicts on children. “It will be a long haul, but with these results, we can get started right away,” he says.ABOUT SEATTLE BIOMEDICAL RESEARCH INSTITUTE:
Hannah Krakauer | Newswise
A whole-body approach to understanding chemosensory cells
13.12.2017 | Tokyo Institute of Technology
Research reveals how diabetes in pregnancy affects baby's heart
13.12.2017 | University of California - Los Angeles Health Sciences
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
13.12.2017 | Health and Medicine
13.12.2017 | Physics and Astronomy
13.12.2017 | Life Sciences