Induction of collagenase-3 (MMP-13) expression in human skin fibroblasts by three-dimensional collagen is mediated by p38 mitogen-activated protein kinase

Collagenase-3 (matrix metalloproteinase-13, MMP-13) is a recently identifie d human MMP with an exceptionally wide substrate specificity and restricted tissue-specific expression. Here we show that MMP-13 expression is induced in normal human skin fibroblasts cultured within three-dimensional collage n gel resulting in production and proteolytic activation of MMP-13. Inducti on of MMP-13 mRNAs by collagen gel was potently inhibited by blocking antib odies against alpha(1) and alpha(2) integrin subunits and augmented by acti vating antibody against beta(1) integrin subunit, indicating that both alph a(1)beta(1) and alpha(2)beta(1) integrins mediate the MMP-13-inducing cellu lar signal generated by three-dimensional collagen. Collagen-related induct ion of MMP-13 expression was dependent on tyrosine kinase activity, as it w as abolished by treatment of fibroblasts with tyrosine kinase inhibitors ge nistein and herbimycin A Contact of fibroblasts to three-dimensional collag en resulted in simultaneous activation of mitogen-activated protein kinases (MAPKs) in three distinct subgroups: extracellular signal-regulated kinase (ERK)1 and ERK2, Jun N-terminal kinase/stress-activated protein kinase, an d p38. Induction of MMP-13 expression was inhibited by treatment of fibrobl asts with a specific p38 inhibitor, SE 203580, whereas blocking the ERK1,2 pathway (Raf/MEK1,2/ERK1,2) by PD 98059, a selective inhibitor of MEK1,2 ac tivation potently augmented MMP-13 expression. Furthermore, specific activa tion of ERK1,2 pathway by 12-O-tetradecanoylphorbol-13-acetate markedly sup pressed MMP-13 expression in dermal fibroblasts in collagen gel, These resu lts show that collagen-dependent induction of MMP-13 in dermal fibroblasts requires p38 activity, and is inhibited by activation of ERR1,2. Therefore, the balance between the activity of ERK;1,2 and p38 MAPK pathways appears to be crucial in regulation of MMP-13 expression in dermal fibroblasts, sug gesting that p38 MAPK may serve as a target for selective inhibition of col lagen degradation, e.g. in chronic. dermal ulcers.