Induction of collagenase-2 (matrix metalloproteinase-8) gene expression by interleukin-1β in human gingival fibroblasts

Collagenase-2 (matrix metalloproteinase-8 or MMP-8) is synthesized mainly by polymorphonuclear neutrophils and plays a crucial role in inflammatory periodontal tissue destruction. We tested the effect of interleukin(IL)1 beta. a proinflammatory cytokine, on collagenase-2 gene expression in cultured human gingival fibroblasts and also compared this effect with IL-I beta -induced changes in collagenase-1 and -3 gene expression. By a combination of reverse transcription-polymerase chain reaction and Southern analysis, IL-1 beta was found to dose-dependently induce gene expression for collagenase-1, -2. and -3 in gingival fibroblasts. Although collagenase-2 mRNA was the least abundant among the three collagenase mRNAs tested in the cultured fibroblast system, addition of 1 ng/ml IL-1 beta significantly increased collagenase-2 gene transcription within 6 h, and maximal stimulation was maintained For 12 to 48 h. Significant mRNA induction was observed with as little as 0.1 ng/ml IL-1 beta. IL-1 beta was also found to increase the stability of collagenase-2 mRNAs after transcription arrest was induced by an RNA polymerase inhibitor. Stimulation of collagenase-2. mRNA expression by IL-1 beta was prevented by pretreatment with cycloheximide, an inhibitor of protein synthesis. These results indicate that IL-1 beta increased mRNA expression for collagenases including collagenase-2 in gingival fibroblasts. The findings also suggest that enhancement of collagenase-2 mRNA expression by IL-1 beta involves both protein synthesis and suppression of mRNA degradation.