Collagen Alpha 1(XI) Is Required for Chondrocyte Differentiation through the AKT/GSK3 β/β-Catenin Signaling Axis in ATDC5 Cells

Cartilage development is a tightly regulated process that involves multiple molecules and signaling pathways. The loss of expression of a single gene can alter cell behavior and disrupt the development of the cartilage. Col11a1 encodes the alpha one chain of the minor fibrillar collagen type XI that is essential in skeletal development. We used an RNAi mediated knockdown approach to investigate the role of Col11a1 expression during chondrogenesis in ATDC5 cells. Col11a1 expression promotes the transition of mesenchymal cells to the chondrogenic phenotype, and reduction of Col11a1 expression interferes with cellular differentiation. Our results indicate that collagen α1(XI) protein is required for chondrocyte cell shape, matrix production, mineralization and gene expression through a mechanism that involves AKT/GSK3β/β-catenin and TCF/LEF activity in ATDC5 cells.