Chondrocyte integrin expression and function

Abstract

The extracellular matrix (ECM) is an “information rich” environment and interactions between the chondrocyte and ECM regulate many biological processes important to cartilage homeostasis and repair including cell attachment, growth, differentiation, and survival. The integrin family of cell surface receptors appears to play a major role in mediating cell‐matrix interactions that are important in regulating these processes. Chondrocytes have been found to express several members of the integrin family which can serve as receptors for fibronectin (α5β1), types II and VI collagen (α1β1, α2β1, α10β1), laminin (α6β1), and vitronectin and osteopontin (αVβ3). Integrin expression can be regulated by growth factors including IGF‐I and TGF‐β. By providing a link between the ECM and the cytoskeleton, integrins may be important transducers of mechanical stimuli. Integrin binding stimulates intracellular signaling which can affect gene expression and regulate chondrocyte function. Further studies are needed to more clearly define the role of integrins in cartilage.