Osteoclasts are multinucleated cells that degrade cartilage as well as bone

Osteoclasts are essential for bone remodelling and are normally found at the bone surface where they create resorption pits. Joints are formed where the extremities of bones meet and articulate. Cartilage is composed of chondrocytes and a collagenous extracellular matrix rich in proteoglycan and collagen that lines and lubricates the joint. The bone-cartilage interface comprises the deep layer of non-calcified cartilage, the calcified cartilage and the underlying subchondral bone. Osteoarthritis (OA) is characterized by a degeneration of articular cartilage and the crosstalk between cartilage and subchondral bone plays an important role in the development and progression of OA. Direct biochemical crosstalk or cellular contact between cartilage and bone might modify the cellular environment and influence disease progression. Whether osteoclasts degrade cartilage has been little explored and is a challenging question. We aim to characterise how osteoclasts can affect cartilage degradation.