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
An ounce of prevention: Research advances on 'scourge' of transplant wards
28.08.2015 | University of Wisconsin-Madison
Hypoallergenic parks: Coming soon?
27.08.2015 | American Society of Agronomy
A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.
The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...
A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).
Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...
In mountainous regions earthquakes often cause strong landslides, which can be exacerbated by heavy rain. However, after an initial increase, the frequency of these mass wasting events, often enormous and dangerous, declines, in fact independently of meteorological events and aftershocks.
These new findings are presented by a German-Franco-Japanese team of geoscientists in the current issue of the journal Geology, under the lead of the GFZ...
Bacteria do not cease to amaze us with their survival strategies. A research team from the University of Basel's Biozentrum has now discovered how bacteria enter a sleep mode using a so-called FIC toxin. In the current issue of “Cell Reports”, the scientists describe the mechanism of action and also explain why their discovery provides new insights into the evolution of pathogens.
For many poisons there are antidotes which neutralize their toxic effect. Toxin-antitoxin systems in bacteria work in a similar manner: As long as a cell...
It comes when called, bringing care utensils with it and recording how they are used: Fraunhofer IPA is developing an intelligent care cart that provides care staff with physical and informational support in their day-to-day work. The scientists at Fraunhofer IPA have now completed a first prototype. In doing so, they are continuing in their efforts to improve working conditions in the care sector and are developing solutions designed to address the challenges of demographic change.
Technical assistance systems can improve the difficult working conditions in residential nursing homes and hospitals by helping the staff in their work and...
20.08.2015 | Event News
20.08.2015 | Event News
19.08.2015 | Event News
28.08.2015 | Physics and Astronomy
28.08.2015 | Health and Medicine
28.08.2015 | Life Sciences