Tissue cooperation in a proteolytic cascade activating human interstitial collagenase.

Abstract

We present a cascade of proteolytic events catalyzed by the proteases secreted by cultured keratinocytes and fibroblasts that results in the activation of interstitial procollagenase. Cultured human skin fibroblasts constitutively secrete interstitial collagenase and stromelysin as proenzymes. In contrast, interstitial collagenase found in serum-free skin organ culture conditioned medium is activated. Cocultivation of the major cellular components of skin organ culture, dermal fibroblasts and epidermal keratinocytes, induces activation of interstitial procollagenase and prostromelysin in the presence of plasminogen. This activation occurs through a urokinasedependent pathway where added keratinocytes secrete the plasminogen activator urokinase, which converts p!asminogen into plasmin. Plasmin is capable of activating purified procollagenase and prostromelysin. Plasmin-dependent activation of procollagenase generates an enzyme species, by amino-terminal processing, identical to those generated by limited proteolysis with trypsin or treatment with organomercurial compounds. Catalytic amounts of activated stromelysin can in turn convert plasmin-or trypsin-activated collagenase into a fully active enzyme by removal of 15 amino acid residues from the carboxyl end of the enzyme. This results in a 5-to 8-fold increase in collagenase specific activity that is due to its proteolytic cleavage and not to the presence of the activator stromelysin. Stromelysin alone in both pro-and activated forms is not capable of efficient activation of human fibroblast interstitial procollagenase.Intensified tissue remodeling during morphogenesis, wound healing, and tumor invasion requires the presence of secreted metalloproteases capable of initiating the degradation of macromolecules ofthe extracellular matrix. Several enzymes of this class have been identified: fibroblast (1-3) and granulocyte (4,5) collagenases, which degrade interstitial collagens, type IV collagenase, which degrades both basement membrane collagen and denatured collagen (gelatin) (6-8), and stromelysin, which degrades proteoglycans (9-13). We have determined the primary structure of fibroblast interstitial collagenase (14), stromelysin (12), and type IV collagenase (7), demonstrated a close structural relationship between these proteins (7), and compared their substrate specificities. Analysis of the genomic organization of the human fibroblast interstitial collagenase gene (15) in comparison with that of rabbit collagenase (16) and rat stromelysin (17) revealed that a close structural relationship on the protein level is reflected in the very similar genomic organization of at least two members of the secreted metalloprotease gene family. Interstitial collagenase (1, 18), stromelysin (12), and type IV collagenase (7) are constitutively secreted by cultured human skin fibroblasts in a proenzyme form and are subject to activation extracellularly. Both procollagenase and prostromelysin are secreted in two forms, one of which contains N-linked complex oligosacc...

Inhibition of furin‐like enzymes blocks interleukin‐1α/oncostatin M–stimulated cartilage degradation

“…This may well be a component of the plasminogen activator (PA)/plasmin cascade, since plasmin is inhibited by ␣ 1 PI and is a known activator of procollagenases (18)(19)(20)(21). These observations suggest that a furin-dependent activation mechanism occurs early in the cartilage assay, while a serine proteinase pathway, possibly the PA/plasmin cascade, is important later in the cartilage assay.…”

“…The precise mechanisms of activation of procollagenases in cartilage are not fully understood. The serine proteinase plasmin is a known activator of several proMMPs, including proMMP-1 (collagenase 1), proMMP-13 (collagenase 3), and proMMP-3 (stromelysin 1) (18)(19)(20)(21). MMP-3 itself can activate other proMMPs, including proMMP-1, proMMP-8 (collagenase 2), proMMP-9 (gelatinase B), and proMMP-13 (22)(23)(24)(25).…”

Body weight and vascular invasion in post-menopausal women with breast cancer

“…Furthermore, a recent study showed that vascular invasion was observed in 47% of tumours excised between days 3 and 12 of the cycle but in only 33% of those undergoing surgery at other times (Badwe et al, 1995). In vitro, oestrogens modulate secretion of at least two proteases, plasminogen activator (Mira-yLopez et al, 1991) and cathepsin D (Rochefort et al, 1990) which can activate a cascade of proteolysis (He et al, 1989). The ability to secrete these proteases has been shown to be an independent adverse predictor of survival in breast cancer (Rochefort, 1990;Duffy et al, 1991 ).…”

Expression of stromelysin-3 in the human placenta and placental bed

“…Indeed, cell-bound u-PA is a key enzyme in the initiation of the plasminogen activation cascade, a major pathway of extracellular proteolysis. Also, u-PA can convert the widely occurring zymogen plasminogen into enzymatically active plasmin (Dano et al, 1985;Liotta, Steeg and Stetler-Stevenson, 1991;P611~inen, Stephens and Vaheri, 1991), which can directly degrade various ECM glycoproteins (Montgomery et al, 1993) and activate other matrix-degrading enzymes, such as prointerstitial collagenase (He et al, 1989;Murphy et al, 1994), pro-gelatinase B and pro-stromelysin-1 which mediate this matrix degradation. As ST3 is able to cleave and inactivate the proteinase inhibitors cited above, the concomitant production of ST3 and plasmin (via u-PA activity) by trophoblastic cells could be seen as a prerequisite for initiating a potent proteolytic cascade that enables the degradation of most ECM components.…”