A b s t r a c tThe equilibrium between deposition and degradation of extracellular matrix(ECM) is essential to normal tissue developement and repair of wound or inflammatory responses. It has recently become apparent that several cytokines and growth factors are capable of modulating fibroblast proliferation and biosynthetic activity. To understand the role of these factors in connective tissue regulation, we examined the effect of interferon-( I F N -) on stromelysin-1 gene expres-sion in cultured human dermal fibroblasts. The steady-state levels of stromelysin-1 mRNA were increased in IFN-treated cultured dermal fibroblasts. In the CAT assay, the stromelysin-1 promoter activity was increased 2.8-fold compared with untreated control. Therfore IFNstimulates the stromelysin-1 promoter activity, resulting in transcriptional enhance-ment of gene expression. Transforming growth factor-( T G F -) showed the antagonistic action to the effects of IFNin cultured dermal fibroblasts. Furthermore, gel mobility shift assays demonstrated enhanced AP-1 binding activities in nuclear extracts from cells incubated with IFN-. These data suggest that IFNis an up-regulator and TGF-is a down regulator on the stromelysin-1 gene expression, respectively, and the AP-1 binding site may be necessary for gene response.Keywords: stromelysin-1, interferon-γ, AP-1, gene expression
IntroductionThe matrix metalloproteinase (MMP)familly, which includes collagenase (MMP-1), gelatinase (MMP-2), stromelysins (MMP-3), matrilysin and metalloelastase, were structurally related zinc-dependent proteolytic enzymes, yet specific activities are divergent (Wo e s s n e r, 1990; McCachren, 1991;Mauviel, 1993). Stromelysin-1 and -2 are closely related, yet distinct from metalloproteinases, and both can degrade many non-collagenous connetive tissue macromolecules such as fibronectin, laminin, elastin, IgG, and proteoglycans (Chin et al,, 1985). Stromelysin-1-producing keratinocytes resided on the basement membrane, whereas stromelysin-2-producing keratinocytes were in contact with the dermal matrix (Saarialho-Kere et al. , 1993). Furthermore, stromelysin-1 expression was prominent in dermal fibroblasts, whereas no signal for stromelysin-2 was observed in any dermal cells (Saarialhokere et al., 1993). Beside participating in normal connective tissue homeostasis, development and remodeling, the proteolytic activity of matrix metalloproteinases contributes significantly to the tissue damage that occurs in chronic inflamatory disease, such as rheumatoid arthritis and osteoarthrtis (Pelletier et al., 1993), as well as tumor invasion (Martrisian, 1990).Metalloproteinases are produced by multiple cell types and typically, their expressions are tightly regulated and limied to periods of active remodelling. The cell typespecific expression of metalloproteinases is regulated by various factors, including cell-matrix interaction, growth factors and cytokines, lipid mediator, tumor promotors, and inflammatory agent such as bacterial lipopolysaccharide ( S a a r i a l h o...