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 derrmal 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 microg/mL. The increase of fibroblast proliferation with 3 microg/mL tryptase was significantly reduced by 15 microg/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 microg/mL. The collagen production in the presence of 10 microg/mL tryptase was significantly inhibited by 50 microg/mL antitryptase IgG antibody. CONCLUSION: Tryptase increases not only the proliferation of human dermal fibroblasts but also type I collagen production.