CYCLOSPORINE-A ENHANCES CYTOKINE AND PHORBOL ESTER-INDUCED FIBROBLASTCOLLAGENASE EXPRESSION

Cyclosporin A is succesfully used in the treatment of scleroderma, a c ondition with excessive deposition of collagen in the dermis. Cultured human dermal fibroblasts were used as a model to study the effects of cyclosporin A on metalloproteinase expression and activity. Fibroblas ts were treated with collagenase inducing agents, phorbol 12-myristate 13-acetate (PMA), cytokines interleukin-1 beta (IL-1 beta), tumor nec rosis factor alpha (TNF alpha), and the calcium ionophore A23187 in th e presence of cyclosporin A under serum-free conditions, and alteratio ns in metalloproteinase expression were studied by Northern hybridizat ion and immunoblotting analyses, and assays for collagenolytic activit y. Induction of collagenase expression by PMA and cytokines was enhanc ed severalfold by 1-10 mu M cyclosporin A. Treatment of cells with cyc losporin A alone caused only a minor increase in collagenase mRNA leve ls. The secretion of immunoreactive collagenase protein and the level of p-aminophenylmercuric acetate activatable collagenase activity were increased by PMA and further enhanced by cyclosporin A. The expressio n of the other metalloproteinases stromelysin-1, 92-kD gelatinase, and 72-kD gelatinase or metalloproteinase inhibitor TIMP-1 were not affec ted by cyclosporin A. Time dependence analysis of the expression of th e mRNAs for c-jun and junB indicated that the induction of these genes persisted significantly longer in cells treated with both PMA and cyc losporin A than in cells treated with PMA alone. Enhanced induction of collagenase mRNA may thus result from prolonged AP-1 activity. The re sults indicate that cyclosporin A potently enhances the expression of collagenase in dermal fibroblasts.