Salivary cystatins induce interleukin-6 expression via cell surface molecules in human gingival fibroblasts.
Recently, family 2 cystatins have been demonstrated to upregulate interleukin-6 (IL-6) production by human gingival fibroblasts [Biol. Chem. 381 (2000) 1143]. To elucidate the mechanism of the IL-6 inducing activity of cystatins, we tested NF-kappa B activation with salivary cystatins SA1 and SA2-stimulated human gingival fibroblast whole cell lysates. The IL-6 production by human fibroblasts in response to these cystatins was inhibited by tyrosine kinase inhibitors and an inhibitor of NF-kappa B activation. The IL-6 inducing activity of the cystatins was depressed by the anti-CD58 monoclonal antibody. These findings supply evidence that cystatins SA1 and SA2 adhere to human fibroblasts and that the event results in tyrosine phosphorylation and upregulation of the release of IL-6 mediated enhancement of NF-kappa B activity.