Type IX collagen interacts with fibronectin providing an important molecular bridge in articular cartilage.

Type IX collagen is covalently bound to the surface of type II collagen fibrils within the cartilage extracellular matrix. The N-terminal, globular noncollagenous domain (NC4) of the α1(IX) chain protrudes away from the surface of the fibrils into the surrounding matrix and is available for molecular interactions. To define these interactions, we used the NC4 domain in a yeast two-hybrid screen of a human chondrocyte cDNA library.

Platelet-rich concentrate supports human mesenchymal stem cell proliferation, bone morphogenetic protein-2 messenger RNA expression, alkaline phosphatase activity, and bone formation in vitro: a mode of action to enhance bone repair.

Objective: Platelet-rich concentrate (PRC) is an autologous growth factor preparation that is in routine use for orthopaedic and maxillofacial surgery. However, there are little data available describing the cellular and molecular mechanisms by which PRC enhances the healing response in an osseous environment. The aim of this study was to identify cellular and molecular events that are modulated in human mesenchymal stem cells (hMSCs) in response to exposure to human PRC generated by a novel filtration-based device (CAPTION, Smith & Nephew Inc).