[Homeostasis and Disorder of Musculoskeletal System.Mechanisms of cartilage development and homeostasis.]

Chondrocytes, which are originated from undifferentiated mesenchymal stem cells, play roles in skeletal development and growth in mammal, and smooth movement of joints. Endochondral ossification is necessary for skeletal development, and the multiple and complex biological events are precisely regulated by several hormones, cytokines, and their downstream signaling and transcriptional regulation. On the other hands, articular chondrocytes physiologically retains their features during a lifetime. Numerous molecules involved in endochondral ossification have been identified and investigation of the molecular mechanisms have amazingly progressed. Although GDF5 and Prg4 were identified as important molecules associated with articular cartilage development and its homeostasis, the molecular mechanisms are very unclear to date.