Loss of mutual protection between human osteoclasts and chondrocytes in damaged joints initiates osteoclast-mediated cartilage degradation by MMPs.
Larrouture QC., Cribbs AP., Rao SR., Philpott M., Snelling SJ., Knowles HJ.
Osteoclasts are multinucleated, bone-resorbing cells. However, they also digest cartilage during skeletal maintenance, development and in degradative conditions including osteoarthritis, rheumatoid arthritis and primary bone sarcoma. This study explores the mechanisms behind the osteoclast-cartilage interaction. Human osteoclasts differentiated on acellular human cartilage expressed osteoclast marker genes (e.g. CTSK, MMP9) and proteins (TRAP, VNR), visibly damaged the cartilage surface and released glycosaminoglycan in a contact-dependent manner. Direct co-culture with chondrocytes during differentiation increased large osteoclast formation (p