During cartilage development, the lineage commitment and condensation of stem cells into chondrocytes and their differentiation involves a ubiquitous signaling cascades and huge numbers of transcriptional factors. The kinetic requirements and the stoichiometry for the expression of key transcriptional factors are relevant and must be met to form proper and functionally competent cartilage tissue. More interestingly also, an exact and precise spatio-temporal distribution of these molecules are as necessary in the proper tissue morphogenesis and patterning as the relevant physical conditions and micro environmental forces playing at the background during embryogenesis. A milestone of experimental achievements has been obtained over the years on several signaling pathways involved in cartilage development. Several fate determining transcriptional factors has also been investigated and determined with regards to the transition of stem cells (pluripotent, embryonic, etc.) into chondrocytes. These transcriptional factors serve as master controllers in chondrocytes proliferation and hypertrophy. Concerns that variability in signaling and transcriptional factors have detrimental effect on cartilage formation and could potentiate most cartilage related diseases have led most scientists to investigate the role of signaling molecules and transcriptional factors implicated in osteoarthritis, rheumatoid arthritis, and other cartilage degenerative diseases. On bases of spatio-temporal distribution of transcriptional factors, there exist functional overlaps, hence, it is difficult to draw a hard line of demarcation of roles at each point of the cell’s life, nonetheless, it is also markedly established that some factors are skewed to the chondrocyte’ survival and proliferation, and others known for their master’s role in the cell’s apoptotic, necrotic and senescence. Here we review some published works on selected signaling pathways and transcriptional factors that are preferentially expressed in chondrogenic cells and their role as major players in cartilage formation, cartilage diseases, along with some highlights of unique signaling molecules that are indispensable in cartilage tissue regeneration and management.
Role of Chondrocytes in Cartilage Formation, Progression of Osteoarthritis and Cartilage Regeneration
