The breakthrough that may provide the first-ever treatment for osteoarthritis centers on an enzyme called G protein-coupled receptor kinase 2 (GRK2). The Penn State team had established through earlier research that the activity of this enzyme plays a key role in the way cells proliferate in heart and kidney disease, which has some parallels with the way the pathological growth of cartilage cells leads to osteoarthritis. Scientists call this process chondrocyte hypertrophy, but have been unable to pinpoint the reasons behind it.
The Penn State researchers may now have found an answer. They started by exploring the activity of GRK2 in patients suffering from osteoarthritis or acute joint injuries and found high levels of the enzyme in their cartilage cells, or chondrocytes. It was found to be playing a central role in the deterioration of the cartilage, errantly leading the cells to destroy the surrounding cartilage rather than keeping it healthy.