Crosstalk Between Human Monocytic U937 Cells and Gingival Fibroblasts in Coculturally Enhanced Matrix Metalloproteinase-2 Expression

Background: Matrix metalloproteinases (MMPs) play a key role in inflammatory periodontal disease. Synergistically enhanced MMP-2 expression in a coculture of human gingival fibroblasts (HGFs) and human monocytic U937 cells was observed. Crosstalk between these two cells via the extracellular matrix metalloproteinase inducer (EMMPRIN) was demonstrated.Methods: Enzyme levels of MMP-2 in HGFs and direct coculture with U937 were examined by zymography. MMP-2 and EMMPRIN expressions of HGFs and U937 were determined in coculture and conditioned cultures (using supernatants from HGF- or U937-conditioned medium). The crosstalk was evaluated by EMMPRIN extrasupplement and EMMPRIN inhibition, through pretreatment of U937 with cyclosporine-A.Results: Direct coculturing of HGFs and U937 enhanced MMP-2 enzyme level and mRNA expression. Coculturing also increased membranous EMMPRIN expression of U937, but not from HGFs. In conditioned cultures, mRNA expression of MMP-2 increased in HGFs which received U937-conditioned ...