Growth Differentiation Factor 5 (GDF-5) Induces Matrix Metalloproteinase 2 (MMP-2) Expression in Periodontal Ligament Cells and Modulates MMP-2 and MMP-13 Activity in Osteoblasts

Growth differentiation factor 5 (GDF-5), a member of the transforming growth factor beta (TGF-) superfamily expressed in periodontal tissues, promotes extracellular matrix (ECM) in periodontal ligament (PDL) cells. Matrix metalloproteinases (MMP) are proteolytic enzymes that degrade ECM and are expressed in PDL cells. To date, little is known about the regulation of MMP synthesis and secretion in PDL cells. The aim of this study is to examine the effects of GDF-5 on MMP production and activity in PDL cells. GDF-5 increased both collagen type I alpha 2 (Col I2) and MMP-2 gene expression in cells derived from mouse PDL tissues after 3 days of culture. Because PDL cells represent a heterogeneous population, we examined gelatinolytic activity and gene expression profiles in an osteoblast cell line. After 6, 12, 24, and 48 hours of culture, GDF-5 increased both Col I2 and MMP gene expression in osteoblasts. GDF-5 also promoted MMP-2 activity as revealed by gelatin zymography after 7 days of culture. In the presence of the p38 MAP kinase inhibitor SB202190, on the other hand, MMP-2 activity was blocked. Taken together, these results indicate that GDF-5 may increase simultaneously the gene expression of type I collagen and MMP-2 in the osteoblast-like cells among the PDL cells and p38 MAP kinase pathway in osteoblast could involve in the regulation of MMP-2 enzyme activity induced by GDF-5.