Integrin signaling in cartilage development

Abstract

Cartilage is one of the major structural elements in the human body and can be exposed to various vulnerable conditions such as osteoarthritis, rheumatoid arthritis, and unexpected joint injuries. Unfortunately, cartilage tissues are not efficiently repaired by innate biological systems. Although medical treatments may ameliorate the symptoms of the patients, the regeneration of the damaged cartilage is yet among the most challenging assignments to the scientist in the field. Cartilage tissues are built by deposition of complex extracellular matrices such as collagen, fibronectin, and laminin. Most of the components in the cartilage tissues are secreted and organized by chondrocytes. Recent studies have revealed a substantial amount of biological mechanisms for cartilage development and differentiation. However, we are still very far from a complete understanding of the chondrogenic procedures and signaling. Among the most intriguing points in chondrogenic signaling is integrin signaling. An increasing amount of data indicates that integrin signaling is critical for chondrocyte differentiation. However, some conflicting, not mutually exclusive per se, data have frequently been reported. In this review, we summarize the functions of integrin signaling for chondrogenesis and suggest future directions to further elucidate this challenging issue.