The Wnt5a Receptor, Receptor Tyrosine Kinase-Like Orphan Receptor 2, Is a Predictive Cell Surface Marker of Human Mesenchymal Stem Cells with an Enhanced Capacity for Chondrogenic Differentiation.

Multipotent mesenchymal stem cells (MSCs) have enormous potential in tissue engineering and regenerative medicine. However, until now, their development for clinical use has been severely limited as they are a mixed population of cells with varying capacities for lineage differentiation and tissue formation. Here, we identify receptor tyrosine kinase-like orphan receptor 2 (ROR2) as a cell surface marker expressed by those MSCs with an enhanced capacity for cartilage formation.

The influence of donor and hypoxic conditions on the assembly of cartilage matrix by osteoarthritic human articular chondrocytes on Hyalograft matrices.

Resurfacing of cartilage defects using cell-seeded, biomaterial grafts is a promising approach for articular cartilage repair and in this study we investigated the ability of human chondrocytes from osteoarthritic joints to generate cartilage tissue under standard conditions in cultured over 21 days on Hyalograft matrices under normoxic (20% O(2)) and hypoxic (5% O(2)) conditions. The results showed that constructs were more chondrogenic when cultured under hypoxic conditions, which resulted in greater production of sulphated glycosaminoglycan and collagen type II within the constructs and the cells expressed higher levels of genes encoding cartilage matrix proteins and chondrocyte transcription factors. However, there were very wide differences in the chondrogenic potential amongst donors as the weight ratio of total sulphated glycosaminoglycan to DNA in constructs varied from above 200 to below 10.

SOX9 transduction increases chondroitin sulfate synthesis in cultured human articular chondrocytes without altering glycosyltransferase and sulfotransferase transcription.

The transcription factor SOX9 (Sry-type high-mobility-group box 9) is expressed in all chondrocytes and is essential for the expression of aggrecan, which during biosynthesis is substituted with more than 10 times its weight of CS (chondroitin sulfate) and is secreted by chondrocytes to form the characteristic GAG (glycosaminoglycan)-rich ECM (extracellular matrix) of cartilage. SOX9 expression rapidly falls during monolayer culture of isolated chondrocytes and this turns off aggrecan and associated CS synthesis. We therefore investigated whether SOX9 transduction of cultured human articular chondrocytes had any effect on the gene expression of the glycosyltransferases and sulfotransferases necessary for GAG biosynthesis.

Chondrogenic differentiation of human bone marrow stem cells in transwell cultures: generation of scaffold-free cartilage.

Human bone marrow stem cells (hMSCs) have been shown to differentiate in vitro into a number of cell lineages and are a potential autologous cell source for the repair and replacement of damaged and diseased musculoskeletal tissues. hMSC differentiation into chondrocytes has been described in high-density cell pellets cultured with specific growth and differentiation factors. We now describe how culture of hMSCs as a shallow multicellular layer on a permeable membrane over 2-4 weeks resulted in a much more efficient formation of cartilaginous tissue than in established chondrogenic assays.