CD147 (Extracellular Matrix Metalloproteinase Inducer-EMMPRIN) Expression by Human Articular Chondrocytes

Background: Integrins are a family of transmembrane proteins that allow communication between the extracellular matrix and the interior of cells. Chondrocytes, cells of articular cartilage, express integrins and these molecules appear to have a variety of roles including mechanotransduction. Integrins are known to associate with a number of accessory molecules such as CD147 that may act to regulate their activity. The purpose of this study was to investigate the expression of CD147 in normal and osteoarthritis human articular cartilage and identify potential roles in mechanical signalling. Methods: Expression of CD147 in normal and osteoarthritis human articular cartilage was examined by the immunostaining and Western-blotting techniques. Potential roles in mechanotransduction were studied by assessing effects of function blocking antibodies on the electrophysiological response to mechanical stimulation. Results: CD147 was extensively expressed by chondrocytes in normal and osteoarthritic cartilage and shown by Western-blotting to have a molecular weight in the region of 35-50 kDa. Function blocking antibodies had no effect on the membrane depolarisation response of chondrocytes from osteoarthritic cartilage to mechanical stimulation. Conclusion: Human articular chondrocytes show extensive expression of CD147 in normal and osteoarthritic cartilage. Roles for this molecule in regulation of chondrocyte function remain to be defined.