Staphylococcus aureus enhances gelatinase activities in monocytic U937 cells and in human gingival fibroblasts

BACKGROUND/PURPOSE: Staphylococcus aureus (S. aureus) has been suggested to be an initiative pathogen in peri-implantitis because of the solid affinity to titanium. However, the detail pathogenesis for the peri-implantitis initiation by S. aureus is still lacking. This study aimed to in vitro examine the gelatinases’ activities of monocytic U937 cell and human gingival fibroblast after challenges with S. aureus lipoteichoic acid (LTA) and peptidoglycan (PGN). MATERIALS AND METHODS: Releases of gelatinases, including matrix metalloproteinase (MMP)-2 and −9, from cells were measured by zymography. The releases were further examined after being given the S. aureus LTA/PGN. Roles of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways on the enzyme releases were examined by administrating inhibitors. RESULTS: S. aureus LTA and PGN increased the activities of pro-MMP-9 from U937 cells and pro-MMP-2 and MMP-2 from gingival fibroblasts. By giving the NF-κB inhibitor, the enhanced gelatinase activities in both cells were attenuated. In U937 cells, the enhanced pro-MMP-9 could further be attenuated by MAPK inhibitors, including extracellular signal-regulated kinase 1 and 2 (ERK1/2), P38 MAPK, and c-Jun N-terminal kinase (JNK) inhibitors; however, the attenuation by MAPK inhibitors could not be observed for MMP-2 in gingival fibroblasts. Nevertheless, in gingival fibroblasts, the pro-MMP-2 could be attenuated by JNK inhibitor. CONCLUSION: S. aureus could enhance gelatinase activities of gingival fibroblasts and U937 cells, via NF-κB. The MAPK pathway was also involved in MMP-9 activity of U937 cells; however, the involvement of MAPK in MMP-2 activity of gingival fibroblasts was questioned.