One potential target is a protein whose structures have now been decoded in detail by scientists from the University of Würzburg. The scientific journal Plos One covers their work in its latest issue.
One in three women and one in five men in the world over the age of 50 currently have excessively low bone density according to the International Osteoporosis Foundation. They therefore carry a significantly increased risk of suffering a bone fracture. The pathological decrease in the density of bone substance, also known as osteoporosis, often develops unnoticed. In healthy people, bone-building and bone-degrading processes occur in equilibrium, whereas degradation predominates in osteoporosis patients.
Sights set on the protein sclerostin
It is no wonder that scientists and pharmaceutical companies are working hard to develop new treatments for osteoporosis. One possible target is the protein sclerostin, which plays a pivotal role in what happens inside bones. “Sclerostin inhibits an important signaling pathway found in bone cells,” explains Professor Thomas Müller. The structural biologist from the Julius von Sachs Institute at the University of Würzburg has spent a long time working with this protein. In 2009, for example, he managed to decode its three-dimensional structure.
Müller was able to show that the protein is composed of three loops that emanate from a central knot. The first and third loops together form a defined structure, while the second loop is highly flexible. “The latter region in particular appears to be primarily responsible for the bone growth inhibitory effect,” says Müller.
Sclerostin inhibits bone growth
Sclerostin acts on the so-called Wnt signaling pathway in the body. This pathway plays a major role in ensuring that bone tissue remains stable. “Wnt proteins form a complex with two types of receptor at the cell surface; this then activates genes that are important for bone growth,” explains Müller. Sclerostin intervenes in this process and, in so doing, prevents activation of the Wnt signaling pathway, thereby generally inhibiting bone growth. “So, if we can block sclerostin using antibodies, for example, it will be possible to restore bone density even in already advanced osteoporosis,” says the scientist.
Now Thomas Müller and his team have succeeded in determining the structures in the sclerostin loop structure that are important for binding the protein to its receptor. Their achievement is reported on in the latest issue of the scientific journal Plos One. In addition, the team has shown that a change to the central knot also inhibits sclerostin. “Our studies reveal that the architecture of sclerostin is also important to the biological activity of the protein,” says Müller.
Building on these results, the scientists have already been able to develop an antibody that neutralizes sclerostin in collaboration with the company AbD Serotec. Its impact on bone growth is currently being examined.
Also helpful with excessive bone growth
This new knowledge concerning the way in which sclerostin works is not just useful for developing a treatment for osteoporosis. It is also conceivable that it may be helpful in the reverse direction, so to speak, namely for treating the bone diseases sclerosteosis and Van Buchem’s syndrome. “People afflicted by these very rare hereditary diseases form too little sclerostin or none at all and therefore suffer from excessive bone growth,” says Müller. In these patients, the bone mass grows so much that it wreaks nerve damage. Since the skull is also affected, loss of sight and hearing are common consequences in the absence of surgery; in extreme cases, excessive intracranial pressure can even lead to death.
With the new findings that show which areas of sclerostin are responsible for its effect and how these must be structured, scientists can now also design peptides that have a sclerostin-like effect, explains Müller. A “minimized” peptide-based sclerostin could represent a new, non-surgical treatment option for sclerosteosis and Van Buchem patients that would significantly improve their quality of life.
Mutational Analysis of Sclerostin Shows Importance of the Flexible Loop and the Cystine-Knot for Wnt-Signaling Inhibition. Verena Boschert, Maarten van Dinther, Stella Weidauer, Katharina van Pee, Eva-Maria Muth, Peter ten Dijke, Thomas D. Mueller. doi:10.1371/journal.pone.0081710
ContactProf. Dr. Thomas Müller,
Gunnar Bartsch | idw
New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University
Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences