Purification and properties of an estrogen-stimulated hydrolase from mouse uterus

A complex of novel protease inhibitor, ovostatin homolog, with its cognate proteases in immature mice uterine luminal fluid

A predominant gelatinolytic enzyme with approximately 26 kDa was observed in gelatin zymogram of immature mice uterine luminal fluid (ULF). Size exclusion analysis revealed that the native size of this enzyme was close to that of human α₂-macroglobulin (α₂-MG), a 725 kDa protein. This large protease was isolated by a series of chromatographic steps on the Sephacryl S-400 and DEAE-Sepharose columns. The results from gelatin zymography and SDS-PAGE analysis supported that this large protease consists of gelatinolytic enzyme and a 360 kDa protein. Through tandem mass spectrometry analysis followed by MASCOT database search, the 360 kDa protein was identified as ovostatin homolog (accession: NP_001001179.2) assigned as a homolog of chicken ovostatin, a protease inhibitor. The co-fractionation analysis by gel filtration and mouse ovostatin homolog (mOH) co-immunoprecipitation experiments demonstrated that the mOH formed a complex with three gelatinolytic enzymes in immature mice ULF. Substrate zymography analysis revealed that the mOH-associated gelatinolytic enzymes were suitable to digest type I collagen rather than type IV collagen. In addition, the refolded mOH-associated 26 kDa gelatinolytic enzyme displayed the type I collagen-digesting activity in the assay, but the other two enzymes did not have this function. RT-PCR analysis showed that mOH gene was abundantly expressed in brain, spinal cord, lung, uterus, and in 17-day embryo. Taken together, our data suggest that mOH/cognate protease system may play a potential role in regulation of tissue remodeling and fetal development.

Effect of estradiol and selected antiestrogens on pro- and antioxidant pathways in mammalian uterus

In this study, we examined the effect of 17 beta-estradiol and selected antiestrogens on uterine NADPH-oxidase activity, superoxide dismutase (SOD) activity, hydride (H.-), dienyl radical and O2 -radical generation, and membrane fluidity. NADPH oxidase activity was positively modulated in estradiol-treated animals and negatively regulated in animals that received injections of AF-45, RU-39411, tamoxifen, or ICI-182780. The SOD activity was markedly reduced in estradiol-treated animals when compared with the control animals. A positive modulation of SOD activity was observed upon treatment with AF45, RU39411, tamoxifen, and ICI 182780, though the potency varied among the individual test compounds. We observed detectable H(.-)-radical generation as evidenced from MNP H.- adduct formation in the uterine cell preparations from untreated control animals. Estradiol produced a tremendous augmentation in the superoxide radical profiles in uterine cell preparations compared to the control levels. All the other compounds that were tested significantly lowered the superoxide levels in the test set-up. AF-45, RU-39411, tamoxifen, and ICI-182780 induced varying orders of suppression of H(.-)-radical generation in the test subjects. There was a significant enhancement in membrane fluidity, hydride radical levels, and dienyl radical generation in the estradiol-treated group. All the antiestrogens did not exhibit a similar action on these parameters. RU-39411 exhibited antiestrogen-like activity in modulating hydride levels and membrane fluidity, whereas it stimulated dienyl radical generation. Thus our tests showed that the selected antiestrogens failed to show estrogen-like activity in these assays. It appears that estradiol exerts feedback control over pro- and antioxidant pathways and that markers of oxidative status could be used as a measure to evaluate the antiestrogenic activity of estradiol agonists/antagonists.

Separation and identification of two components of an estrogen-responsive, calcium-dependent arginine esteropeptidase

Arginine esteropeptidase is an estrogen-responsive, calcium-dependent enzyme in rat uterine cytosol. It appears in increased amounts 3 h after administration of physiologic amounts of 17 beta-estradiol to an immature female rat. Its reaction was resolved into two parts: a calcium-dependent activation of the enzyme and a calcium-independent hydrolysis of the substrate. The esteropeptidase was separated by DEAE cellulose chromatography into two components. The properties of component A, the activator, are distinct from those of component B, the enzyme, which has the same response to inhibitors as serine proteinases. Both components are subject to estrogen control. Component A is present in significant amounts only after estrogen stimulation. Component B is increased 3-fold after estrogen stimulation. The responses of the two components to inhibitors, their different molecular weights and chromatographic behavior and the pH optima of their reactions distinguish them from each other and from other uterine proteinases previously described.

The effects of sequential administration of 17 beta-estradiol on the synthesis and secretion of specific proteins in the immature rat uterus

We report here results of a study of the effect of sequential administration of 1 microgram 17 beta-estradiol in vivo on the incorporation of L-[35S]methionine into specific proteins in vitro in the immature rat uterus. One-dimensional SDS-PAGE analysis of labeled secreted uterine proteins and cellular proteins extracted from the luminal epithelial and from the stroma plus myometrial uterine fractions revealed that estradiol preferentially stimulated the synthesis of 110 K, 74 K and 66 K secreted proteins, 180 K and 110 K epithelial proteins and a 175 K stroma-myometrial protein among others, while it decreased the relative rate of synthesis of a 32.5 K secreted protein and a 70 K stroma-myometrial protein. The 110 K protein, a secreted luminal epithelial protein whose labeling in vitro dramatically increased greater than 60-fold per mg endometrial DNA after in vivo estrogen stimulation, may be a useful marker for studying estrogen action in the luminal epithelium of the immature rat uterus. Comparison of the secreted proteins labeled at 28 h (4 h after a second injection) and at 54 h (6 h after a third injection) revealed that estradiol effected a sequential change in the pattern of synthesis of secreted uterine proteins in vitro. Comparison of the number and magnitude of changes in the synthesis of specific proteins in the luminal epithelium and the stroma plus myometrium revealed that protein synthesis in the luminal epithelium is clearly more responsive to estradiol and readily distinguishable from the responsiveness of the stroma plus myometrium.