Activation of MMP-2 by Porphyromonas gingivalis in human periodontal ligament cells

It has been reported that matrix metalloproteinase (MMP) produced by host cells plays a major role in periodontal tissue destruction. In addition, secreted virulence factors from Porphyromonas gingivalis can alter MMP secretion and cause activation in host cells that lead to the tissue degradation. In this study, we examine the effects of P. gingivalis supernatant on matrix metalloproteinase‐2 (MMP‐2) activation in human periodontal ligament (HPDL) cells. Cultures of HPDL cells were treated with P. gingivalis supernatant for 48 h and the level of MMP‐2 activation was monitored by gelatin zymography. The profound activation of MMP‐2 was seen only in the treated group. The activation of MMP‐2 was inhibited by MMP inhibitors phenanthroline and EDTA, but not serine protease or cysteine protease inhibitors. To study the correlation between the expression of membrane‐type‐1 matrix metalloproteinase (MT1‐MMP) and the activation of MMP‐2, the level of MT1‐MMP was analyzed. The results from reverse‐transcription polymerase chain reaction (RT‐PCR) and Western analysis indicated that P. gingivalis supernatant up‐regulated the expression of MT1‐MMP in both transcription and translation levels within 48 h. These results suggest that P. gingivalis supernatant can activate MMP‐2 in HPDL cells and the mechanism of activation may involve the increased amount of MT1‐MMP. It is possible that the activation of MMP‐2 by P. gingivalis plays a role in the process of chronic periodontitis.