New protein that plays part in arthritis discovered

Cartilage is central to proper growth and articulation of the joint. The cartilage tissue is composed of chondrocytes and a dense extracellular matrix, which in turn is composed of water, proteoglycans and collagens.

The Boise State biologists found that a protein called collagen XI interacts with specific proteins in the part of the tissue that provides structural support to the cell. Collagen XI is one of the few proteins that is known to prevent arthritis, and when it is mutated or absent, the individual will develop arthritis early in life. Even knowing this, the progression of the disease is still poorly understood by scientists. This lack of understanding prevents the development of effective treatments.

"Knowing which proteins collagen XI binds to could have significant implications in helping clinicians monitor cartilage health as well as diagnose and treat debilitating diseases like arthritis," said study coauthor Julia Oxford, biology professor and director of the Biomolecular Research Center. "Understanding these complex gene families will make major improvements in the quality of life for those dealing with a broad spectrum of arthritic syndromes. If we know what the structure should look like, we can look for changes caused by disease and figure out ways to stop and treat it."

The study appears online in the journal Proteomics.

To conduct the research, Boise State scientists studied tissue and used affinity chromatography and mass spectrometry to identify proteins that can interact with collagen XI. They found several molecules and cellular proteins that interact with it directly or indirectly, including proteoglycans and matricellular molecules, both of which play a significant role in tissue integrity and tissue development.

Oxford said based on their findings, collagen XI has the potential to be used as a diagnostic tool to predict which individuals are predisposed to the development of osteoarthritis.