Mast cell tryptase stimulates both human dermal fibroblast proliferation and type I collagen production

Background Mast cell tryptase has been shown to be mitogenic for fibroblasts, however, it still remains unknown whether mast cell tryptase stimulates collagen production by human dermal fibroblasts. Objective We have investigated the effect of mast cell tryptase on type I collagen production by human dermal fibroblasts as well as the proliferation of the fibroblasts. Methods Tryptase isolated from human lung tissue was added to the culture of fibroblasts from normal dermis, and the fibroblast proliferation and the activity of type I collagen synthesis in the supernatants were assayed, respectively. Results Fibroblast proliferation was increased with tryptase in a concentration-dependent manner, and a significant increase was observed in the presence of tryptase at concentrations from 0.01 to 10 mu g/mL. The increase of fibroblast proliferation with 3 mu g/mL tryptase was significantly reduced by 15 mu g/mL antitryptase IgG antibody, which was demonstrated to inhibit fibrinogenolysis of tryptase. On the other hand, the production of type I collagen by the fibroblasts was significantly increased with tryptase at a concentration of 10 mu g/mL. The collagen production in the presence of 10 mu g/mL tryptase was significantly inhibited by 50 mu g/mL antitryptase IgG antibody. Conclusion Tryptase increases not only the proliferation of human dermal fibroblasts but also type I collagen production.