SYDNEY, Feb. 3 (UPI) -- In a landmark discovery, a team of Australian scientists said Monday they have created a three-dimensional map of a protein that seems to be involved in the development of several serious diseases such as cancer, osteoporosis and rheumatoid arthritis.
The discovery, the scientists said, could lead to new drugs to help "switch off" these and other diseases, bringing relief to millions of sufferers worldwide.
The research was led by Australia's Commonwealth Scientific and Industrial Research Organization and the Ludwig Institute for Cancer Research in Melbourne.
"This is the first step in developing new ways to stop a disease in its tracks," the CSIRO's senior researcher, Kim Branson, told United Press International.
The protein, called the Interleukin 6, or IL-6, receptor, is found on the surface of many types of cells. It binds to IL-6, an immune system hormone, "catching" it, researchers said, a bit like a baseball mitt catching a baseball.
IL-6 is part of a family of hormones called cytokines. It is produced in tiny quantities in the liver and floats around in the bloodstream, but it plays a critical role in the immune system. It helps turn on antibody production and stimulates immune cell production and activation. For example, whenever the skin is cut, IL-6 instructs immune cells to attack harmful bacteria at the site of the wound.
At times, however -- no one knows why -- IL-6 can go haywire. It instructs cells to attack but never rescinds that instruction -- immune cells are activated but not turned off.
This defective interaction has been implicated in the development of post-menopausal osteoporosis, auto-immune diseases and prostate cancer. It also is involved in several damaging inflammatory diseases -- rheumatoid arthritis, in particular -- and is thought to contribute to the development of some forms of cardiovascular disease.
The researchers determined the three-dimensional atomic structure of the IL-6 receptor using a process called X-ray crystallography. It involves growing a crystal from the pure protein and shining an X-ray beam through it to determine its unique structural patterns.
Based on crystallography images, researchers have developed a theoretical atomic model of how the IL-6 receptor interacts with its hormone, IL-6. The data should help determine how the protein initiates biochemical changes in cells that are sensitive to it.
"Knowing the shape of the IL-6 receptor means we can start working on much more targeted drug design," said Branson. "Using the baseball analogy, what we'll be looking to develop is something to stop the baseball from sticking in the mitt."
Rob Moritz, one of the Ludwig Institute's researchers on the project, agreed.
"If we can discern the shape of the receptor, we can create molecules to turn it on or off," Moritz told UPI.
Branson said drug development remains years away. "To go from a structure to a drug is a big step," he said. "But knowing the structure knocks about five years off the design process." Branson said human drug trials could begin in five years.
Dr. Graham Mayrhofer, of the Department of Molecular Biosciences at the University of Adelaide, and a leading expert on arthritic conditions, told UPI the finding could yield major benefits for people afflicted with inflammatory conditions such as arthritis that affect about 1 percent of the population in developed countries.
"If you can stop the IL-6 receptor from misbehaving then you can start coming up with new therapies that will increase the quality of life for many people," he said.
Mayrhofer added that the discovery could not only lead to improved therapies, but also help create therapies with fewer side-effects than those used now.
