ACAN and osteoarthritis: For example, a disintegrin and metalloproteinase with thrombospondin motif 1 (ADAMTS1) is known to cleave aggrecan, a critical component for cartilage structure [58]; bone morphogenetic protein (BMP) receptor type 1B (BMPRB) is a receptor for BMP, and BMP signalling is essential for chondrocyte proliferation, survival and differentiation [59]; and IL-6R interacts with IL-6, one of the pro-inflammatory cytokines increased in osteoarthritis [60].