Progesterone regulates the activity of collagenase and related gelatinases A and B in human endometrial explants.

Abstract

Explants of human endometrium were cultured to study the release of matrix metalloproteinases (MMPs). Analysis of conditioned media by zymography revealed latent and active forms of co ,genase (MMP-1, EC 3.4.24.7), 72-kDa gelatinase A (MMP-2, EC 3.4.24.24), and 92-kDa gelatinase B EC 3.4.24.35). These proteinases were identified by their Mr, their inhibition by tissue inhibitor of metalloproteinases, and the activation of their zymogens by trypsin or aminophenylmer acetate. In the absence of sex hormone, explants released large a ts of enzyme activities, as measured by densitometry of zymogra or in soluble assays. Physiological concentrations of progesterone (10-200 nM) almost totally abolished the release of coilagenase, of total gelatinase activity, and of the active form of gelatinase B and largely inhibited the release of the active form of gelatinase A. These effects, which were antgoz by mifepristone (RU 38486), suggest that progesterone restrains endometrial tissue breakdown by blocking the secretion and activation of MMPs.The stroma of the human endometrium shows striking structural changes, especially during the second half of the menstrual cycle (1). If no pregnancy develops, interstitial shrinkage due to extracellular-matrix breakdown occurs and leads to hemorrhagia and mucosal shedding. The mechanisms of endometrial-tissue breakdown initiated by the fall of plasma progesterone and estradiol are still obscure. A major role of lysosomal enzymes (2) is not supported by biochemical evidence (3), whereas matrix metalloproteinases (MMPs), a family of neutral nonlysosomal enzymes, appear to be plausible agents of the remodeling of the extracellular matrix of the human endometrium (4).MMPs share similar structural domains and properties (for review, see ref. 5), are secreted as zymogens in the extracellular space, are activated by proteolytic cleavage, and are inhibited by the tissue inhibitors of metalloproteinases (TIMPs). A key feature in the regulation of extracellularmatrix degradation seems to be a fine local balance between MMPs, their activators, and their inhibitors. Interstitial collagenase (MMP-1, EC 3.4.24.7) specifically cleaves the fibrillar collagens into one-fourth and three-fourth fragments, which are susceptible to further degradation by other proteases, among which are two other MMPs, gelatinase A (MMP-2, 72 and 65 kDa, EC 3.4.24.24) and gelatinase B (MMP-9, 92 and 84 kDa, EC 3.4.24.35). Both enzymes are also able to degrade other substrates present in human endometrium (1), such as collagen types V and IV. A third subclass of MMPs has a broad spectrum of substrates and comprises stromelysin 1 (MMP-3, EC 3.4.24.17) and matrilysin EC 3.4.24.23).We have studied the possible involvement of MMPs in human endometrial remodeling, using a culture system that maintains the tissue in a similar microenvironment as in situ and responds to sex hormones for several days (3). This system allowed us to demonstrate that the human endometrium secretes collagenase and gelatinases A and B. The secr...

Stromal-epithelial interaction mediates steroidal regulation of metalloproteinase expression in human endometrium.

“…Recent reports from our laboratory and others (3)(4)(5)(6) (25)(26)(27)(28)(29)(30). While a principal role for the stroma has been often proposed in mediating steroid action during growth and differentiation in numerous adult tissues (23), including the endometrium (24), our study demonstrates that stromal cells can mediate progesterone suppression of an epithelial-specific protein.…”

“…In the absence of implantation and the continued progestational environment of pregnancy, the superficial functionalis region of the endometrium undergoes degradation and is expelled with menstrual blood flow. Several laboratories have recently described the expression of matrix metalloproteinases (MMPs) in the normal, cycling human endometrium (3)(4)(5)(6). These enzymes degrade many components of the extracellular matrix, including proteoglycans, glycoproteins, and basement membrane collagens (7).…”

Testosterone inhibits matrix metalloproteinase-1 production in human endometrial stromal cells in vitro

“…However, the MPA-induced decrease in MMP-1 in HESCs was mainly due to its androgenic activity, because FLU recovered the repressive effect of MPA to a level similar to that induced by testosterone or natural progesterone. The repressive effects of progestins on the production of MMP-1 in the human endometrium have been reported before (Marbaix et al 1992, Lockwood et al 1998. They showed inhibition of MMP-1 expression using explants of human endometrium (Marbaix et al 1992) and cultured HESCs (Lockwood et al 1998); however, the mechanism of the regulation on transcription of MMP-1 by progesterone is not yet understood.…”

“…The repressive effects of progestins on the production of MMP-1 in the human endometrium have been reported before (Marbaix et al 1992, Lockwood et al 1998. They showed inhibition of MMP-1 expression using explants of human endometrium (Marbaix et al 1992) and cultured HESCs (Lockwood et al 1998); however, the mechanism of the regulation on transcription of MMP-1 by progesterone is not yet understood. Progesterone may regulate MMP-1 gene via non-classical DNA sequences (Hulboy et al 1997).…”

Involvement of Fibronectin Type II Repeats in the Efficient Inhibition of Gelatinases A and B by Long-chain Unsaturated Fatty Acids

“…Addition of fatty acid after the digestion of fluorogenic substrate had no effect on the fluorescent signal. Nonlinear regression analysis with the Grafit computer software (R. J. Leatherbarrow, Erithacus Software) allowed us to calculate the best estimates of the equilibrium dissociation constant of the enzyme-inhibitor complex or inhibition constant K i , using the integrated Equation 1 (29), (30). The 50% inhibitory concentrations (IC 50 ) of fatty acids for gelatinase A were determined using the Grafit computer software.…”