Progress of research in osteoarthritis. Gene expression and its regulatory mechanisms in the degenerative cartilage in osteoarthritis

Spatiotemporal variations of pathological changes were observed in the osteoarthritis joints. Gene expressions vary depending on the zones in the cartilage. For example, the expressions of degradative enzymes such as matrix metalloproteinases were enhanced in the superficial zone whereas the expression of matrix proteins enhanced at the deep zone. Many factors such as mechanical stress, aging, genetic background, inflammation and phenotypic changes of chondrocytes influence the pathogenesis of osteoarthritis, suggesting the involvement of many regulatory mechanisms in the gene expression. However, discoveries of regulatory factors that provide common pathways for the various phenomenon observed in the osteoarthritis cartilage suggest the interaction and co-operation of these important factors to conduct the pathology of degenerative cartilage.