2012 Volume 21 Issue 2 Pages 141-150
This is the first report describing neurogenic factor of Netrin-1 related to chondrogenesis or osteogenesis in a human cells. Netrin is a morphogenetic factor that induces a growth cone of an axial filament of the nervous system. However, the roles of Netrin in chondrogenesis or osteogenesis are not yet understood. We analyzed the relationship between Netrin and bone morphogenetic protein-2 (BMP-2) in chondrogenesis or osteogenesis, using a human chondrocyte-like cell line (USAC), which also retains multi-potency to differentiate into osteoblasts and adipocytes. Netrin-1 mRNA was decreased in USAC cells, though the expression was increased during osteogenic differentiation at the stage when osteocalcin mRNA were increased by BMP-2. Furthermore, inhibition of Netrin-1 gene increased Cbfa1 mRNA expression, and decreased Sox9 mRNA expression. We also found that Netrin-1was strongly expressed in immature chondrocytes of cartilage-like tissues that were formed in an exo vivo experiment with diffusion chambers. These findings indicate that Netrin-1 and BMP-2 regulates in the stage dependent process of mesenchymal cell differentiation to chondrocytes or osteoblasts.
