| 1. |
- Casslén, B, et al.
(författare)
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Plasminogen activators in the human endometrium, cellular origin and hormonal regulation.
- 1992
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Ingår i: Blood Coagulation and Fibrinolysis. - 0957-5235 .- 1473-5733. ; 3:2, s. 133-8
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Tidskriftsartikel (refereegranskat)abstract
- Endometrial tissue explants in culture were found to release urokinase-type plasminogen activator (u-PA) and tissue-type plasminogen activator (t-PA). In order to identify their cellular origin and possible hormonal regulation, enriched cultures of glandular epithelial cells and stromal cells were prepared from fresh endometrium, and the cultures treated with hormones. Both epithelial and stromal cell cultures were found to secrete u-PA and t-PA. Treatment of epithelial cell cultures with oestradiol, progesterone and DH-testosterone had no effect on the secretion of t-PA or u-PA. In stromal cell cultures, on the other hand, the secretion of u-PA was significantly reduced after treatment with progesterone, whereas oestradiol and DH-testosterone had no effect. This reduction of u-PA antigen in the tissue culture medium did not result from a reduction of the relative level of u-PA mRNA in the cells, suggesting that the synthesis of u-PA was not reduced. Alternatively, an increased clearance of u-PA by the cells from the medium may explain the reduction. This in vitro observation probably reflects the in vivo reduction of u-PA in endometrial secretion during the secretory phase.
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| 2. |
- Casslén, B, et al.
(författare)
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Progesterone regulation of plasminogen activator inhibitor 1 (PAI-1) antigen and mRNA levels in human endometrial stromal cells.
- 1992
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Ingår i: Thrombosis Research. - 0049-3848 .- 1879-2472. ; 66:1, s. 75-87
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Tidskriftsartikel (refereegranskat)abstract
- Plasminogen activator activity decreases in the endometrium in the secretory phase of the menstrual cycle. This is partly due to decreased release of urokinase plasminogen activator in response to progesterone. Plasminogen activator inhibitor type 1 (PAI-1) is an efficient inhibitor of both tissue-type and urokinase-type plasminogen activators, and may therefore be instrumental for the control of plasminogen activation. In this study we examined the effects of steroid hormones on PAI-1 release and PAI-1 mRNA levels in primary cultures of human endometrial stromal cells. In these cells the secretion of PAI-1 was increased by progesterone in a dose and time dependent way, but was not affected by estradiol. The progesterone induction of PAI-1 secretion was preceded by a 7-8 fold increase of the steady state level of PAI-1 mRNA in the cells, suggesting that progesterone activates PAI-1 gene expression. Cultured endometrial glandular epithelial cells were found to release only insignificant amounts of PAI-1 with or without hormone treatment. The effect of progesterone on endometrial stromal cells was mimicked by DH-testosterone. However, while the response to progesterone was completely blocked by ZK112993, a potent antagonist of the progesterone receptor, the response to DH-testosterone was partially blocked by ZK112993, and partially by OH-flutamide, a potent antagonist of the androgen receptor. This suggests that a secretory response on PAI-1 expression is mediated via androgen receptors in endometrial tissue.
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| 3. |
- Descheemaeker, K A, et al.
(författare)
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Interaction of AP-1-, AP-2-, and Sp1-like proteins with two distinct sites in the upstream regulatory region of the plasminogen activator inhibitor-1 gene mediates the phorbol 12-myristate 13-acetate response.
- 1992
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 267:21, s. 15086-91
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Tidskriftsartikel (refereegranskat)abstract
- Phorbol 12-myristate 13-acetate induces a 3- and 10-fold induction of chloramphenicol acetyltransferase (CAT) activity in HT1080 and HeLa cells, respectively, following transient transfection of a 336-base pair plasminogen activator inhibitor-1 (PAI-1) promoter fragment linked to a CAT reporter gene. Substitution mutations in the regions encompassing nucleotides -78 to -69 (TGGGTGGGGC) or -61 to -54 (TGAGTTCA), but not in the regions -155 to -149 (TGCCTCA) or -84 to -76 (AGTGAGTGG) reduced this induction. Gel electrophoresis of double-stranded -65 to -50 oligonucleotides of the PAI-1 promoter region and nuclear extracts from Hela cells produced a gel shift pattern similar to that obtained with a AP-1 consensus oligomer, and excess unlabeled AP-1 oligomer reverted binding, suggesting that this region of the PAI-1 promoter is an AP-1-like binding site. Gel electrophoresis of double-stranded -82 to -65 oligonucleotides with HeLa nuclear extracts revealed a gel shift pattern of three bands; Sp1 consensus oligomer competed with the binding to two of these bands and AP-2 consensus sequence oligomer with the binding to the third band. The -82 to -65 oligomer also bound to purified AP-2 and Sp1 proteins. Southwestern blotting of HeLa nuclear extracts revealed that the labeled oligomer spanning region -82 to -65 bound to proteins with molecular masses of 52 and 72 kDa. Consensus AP-2 oligonucleotides competed for binding of the labeled -82 to -65 oligonucleotide to the 52-kDa protein, but consensus Sp-1 oligonucleotides did not compete for binding to the 72-kDa compound. The 72-kDa component binding to the -82 to -65 region may represent a new protein involved in transcriptional regulation.
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| 4. |
- LaPolt, P S, et al.
(författare)
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Basic fibroblast growth factor induction of granulosa cell tissue-type plasminogen activator expression and oocyte maturation : potential role as a paracrine ovarian hormone.
- 1990
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Ingår i: Endocrinology. - 0013-7227 .- 1945-7170. ; 127:5, s. 2357-63
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Tidskriftsartikel (refereegranskat)abstract
- Gonadotropin-induced ovulation is associated with oocyte maturation and preovulatory increases of tissue plasminogen activator (tPA) expression. Basic fibroblast growth factor (bFGF), an angiogenic factor found in many organs including the ovary, modulates steroidogenesis in granulosa cells and increases PA activity in endothelial cells. Here studies were performed to examine the possible roles of bFGF as an intragonadal regulator of tPA expression and oocyte maturation. In cultured granulosa cells, bFGF caused a time-dependent (onset at 24 h) and dose-dependent (ED50 = 0.6 nM) increase (up to 5-fold) in tPA enzyme activity as measured by the fibrin overlay technique. Northern blot hybridization also revealed that treatment of cells with bFGF (2 nM) increased the level of the 22S tPA messenger RNA. Slot blot analysis indicated that the effects of bFGF were time dependent and dose dependent; tPA message levels increase before tPA activity levels. bFGF (0.6 nM) also significantly increased granulosa cell cAMP production in both the absence and presence of a phosphodiesterase inhibitor. In follicle-enclosed oocytes incubated for 24 h in media with or without increasing concentrations of LH or bFGF, germinal vesicle breakdown was observed in only 1.6% of controls, but 85% of LH (1 microgram/ml)-treated oocytes underwent maturation. Likewise, bFGF induced germinal vesicle breakdown (10-80%) over a dose range of 0.6 to 333 nM. In the same follicles, bFGF, like LH, also stimulated prostaglandin E production. These results, coupled with the identification of bFGF in growing follicles, suggest that bFGF acts as an intraovarian inducer of granulosa cell tPA gene expression and oocyte maturation.
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| 5. |
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| 6. |
- Peng, X R, et al.
(författare)
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Localization of luteinizing hormone receptor messenger ribonucleic acid expression in ovarian cell types during follicle development and ovulation.
- 1991
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Ingår i: Endocrinology. - 0013-7227 .- 1945-7170. ; 129:6, s. 3200-7
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Tidskriftsartikel (refereegranskat)abstract
- The action of LH is mediated through specific plasma membrane receptors that are both up- and down-regulated in the ovary during the reproductive cycle. Using immature rats treated with PMSG and hCG as a model system, we have studied the regulation and distribution of LH receptor mRNA in different cell types during follicle development, ovulation, and luteinization by Northern blot and in situ hybridization. In untreated rats, LH receptor mRNA was below the detection level in granulosa cells, cumulus cells, and oocytes, while low levels of LH receptor mRNA were found in the thecal cells. After stimulation with PMSG, expression of LH receptor mRNA was enhanced in the thecal-interstitial cells, while a more dramatic increase in receptor mRNA abundance took place in granulosa cells of large tertiary follicles. In these follicles, the abundance of LH receptor mRNA varied among different subpopulations of granulosa cells, with mural granulosa cells close to the basement membrane exhibiting higher levels than granulosa cells located closer to the antrum, and cumulus cells and the oocyte lacking detectable hybridization signal. The uneven expression of LH receptor mRNA endows different ovarian cells with varying hormonal responsiveness. After an ovulatory dose of hCG, LH receptor mRNA levels were dramatically decreased, particularly in the granulosa cells of preovulatory follicles, to reach the lowest levels just before ovulation. During the transformation of ovulated follicles into corpora lutea, the expression of LH receptor message was again increased. Our results reveal that the previously documented regulation of the LH receptor-binding activity during ovarian development correlates with expression of the LH receptor transcripts, suggesting that the LH receptor gene is regulated in a complex manner during the periovulatory period to achieve cell-specific expression together with gonadotropin induction and suppression of receptor gene activity.
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| 7. |
- Strandberg, L, et al.
(författare)
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Fluorescence studies on plasminogen activator inhibitor 1 : reactive centre cysteine mutants remain active after fluorophore attachment.
- 1994
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Ingår i: Thrombosis Research. - 0049-3848 .- 1879-2472. ; 76:3, s. 253-67
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Tidskriftsartikel (refereegranskat)abstract
- To investigate structural-functional aspects of plasminogen activator inhibitor 1 (PAI-1) we have taken advantage of the lack of cysteines in the PAI-1 molecule and replaced Ser344 (P3) and Asn329 (P18) with cysteine residues, thereby creating unique attachment sites for extrinsic fluorescent probes. After expression in E. coli and purification to homogeneity, both of the mutant proteins were found to have similar biochemical characteristics as wild type PAI-1 (wtPAI-1). Following labelling with 4-chloro-7-nitrobenzofurazan (NBD) and 2-(4'-iodoacetamido-anilino)naphtalene-6-sulfonic acid (IAANS) the mutant inhibitors showed similar inhibitory activities and heat stability as wtPAI-1. The purified complex between uPA and NBD-labelled P3cys mutant was found to be extremely stable, suggesting that no slow cleavage or reversible reaction occurs in complexes that have been properly formed. The rate of labelling of both mutants was decreased when the mutants were in the latent form indicating that these cysteine residues may be less accessible in the latent configuration. The PAI-1 mutants labelled with both NBD and IAANS could convert from the active to the latent form, but P3cys labelled with the larger IAANS chromophore showed a two fold decrease in the rate of conversion to latency, suggesting that a large chromophore in the P3 position may interfere with the active to latent conversion. The fluorescence spectra of the two NBD labelled mutants were similar, but the intensity was three times higher for the P3cys mutant than for P18cys. No significant spectral changes could be seen when the P3cys mutant was transferred to latency. In contrast, the P18cys mutant showed a major change in the excitation spectra characteristic of migration of the NBD chromophore from a thiol to an amine. Complex formation with uPA had no effect on the fluorescence spectrum of P18cys-NBD while the spectrum of P3cys-NBD revealed changes consistent with a restriction of the mobility of NBD probe in the uPA-PAI-1 complex.
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