Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Testicular peritubular cells produce a paracrine factor termed PModS that has dramatic effects on Sertoli cell function in vitro. The current study was designed to examine the actions of PModS and hormones on Sertoli cell aromatase activity and plasminogen activator production at various stages of pubertal development. Sertoli cells were isolated from 10-, 20-, and 35-day-old rats (ages correspond to prepubertal, midpubertal, and late-pubertal stages of development). Aromatase activity was found to be high and hormone-responsive in prepubertal Sertoli cells and to decline and be nonresponsive to hormones in late-pubertal Sertoli cells. FSH was the only hormone found to influence aromatase activity and estrogen production. PModS alone was not found to affect aromatase activity at any of the developmental stages examined. Interestingly, PModS was found to suppress the ability of FSH to stimulate aromatase activity and estrogen production in midpubertal Sertoli cells. Results imply that PModS may promote Sertoli cell differentiation to a more adult stage of development that is less responsive to FSH in stimulating aromatase activity. In contrast to aromatase activity, plasminogen activator production was found to increase during pubertal development. Production of Sertoli cell tissue-type plasminogen activator (tPa) was stimulated by FSH at each of the developmental stages examined, whereas production of urokinase-type plasminogen activator (uPa) was influenced by FSH only in prepubertal Sertoli cells. Insulin also stimulated uPa and tPa production by prepubertal Sertoli cells, and retinol significantly suppressed uPa production and the ability of FSH to stimulate tPa production by midpubertal Sertoli cells.
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PMID:Developmental regulation of Sertoli cell aromatase activity and plasminogen activator production by hormones, retinoids and the testicular paracrine factor, PModS. 157 55

It is well known that cultured Sertoli cells secrete plasminogen activators (Lacroix et al., Mol Cell Endocrinol 1977; 9:227-236; Hettle et al., Biol Reprod 1986; 34:895-904). We now show that testicular cells in culture also secrete gelatinolytic metalloproteinases. Gelatin zymographic analysis of concentrated culture medium proteins reveals that Sertoli cells secrete gelatinases of 185 kDa, 110 kDa, 83 kDa, 76 kDa, and 72 kDa in addition to plasminogen activators (PAs). Gelatinase 185 kDa is induced by FSH. Media from Sertoli (epithelial)/peritubular (mesenchymal) cell cocultures contain the Sertoli cell gelatinases and one FSH-stimulated gelatinase of 50 kDa, indicating that gelatinase 50 kDa is regulated by both FSH and cell-cell interactions. A 50-kDa fibronectinolytic activity is also present in the coculture medium from cells grown in the presence of FSH. Casein zymography demonstrates a prominent 30-kDa protease only in media from cocultures. Peritubular cells secrete urokinase-type plasminogen activator (u-PA) and exhibit slight degrading activity at 86 kDa and 74 kDa. The gelatinases are most active in the pH range 7.3-8.5 and are completely or partially inhibited by metal ion chelators indicating that they are metalloproteinases. Our data demonstrate that testicular cells in culture secrete several gelatinases in addition to PAs, and that FSH and coculture conditions regulate some of these secreted proteases. We suggest that the highly regulated secretion of these proteases may well be of physiological importance during testicular development and spermatogenesis.
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PMID:Secreted metalloproteinases in testicular cell culture. 212 32

The hormonal regulation of the human urokinase type plasminogen activator (uPA) gene has been studied by introducing into mouse and rat Sertoli cell primary cultures a recombinant plasmid, in which the transcription regulatory elements of the cloned human uPA gene drive the expression of the bacterial chloramphenicol-acetyl-transferase gene. It was found to be expressed and regulated by FSH and (Bu)2cAMP in the mouse cells only, in agreement with data on the expression of the endogenous gene in rat and mouse gonads. The stimulation of transcription by FSH was evident in cultures from 13-day-old but not from 18-day-old mice, even though (Bu)2cAMP induction could be observed at both ages. Phorbol-myristate acetate was found to activate the human uPA promoter in Sertoli cell cultures from mice of both ages, even though the effect was less evident in cultures of 18-day-old animals. Deletion analysis of the human uPA 5'-flanking region showed that the distal enhancer element is not needed for (Bu)2cAMP induction, and that at least two promoter regions are involved in (Bu)2cAMP induced transcription. One of these cAMP responsive regions lies between nucleotides -72 and -29 from the CAP site. The sequence of this region would suggest the binding of transcription factor AP-2, a cell-specific mediator of both cAMP and phorbol esters action on gene expression. However, these sequences do not mediate phorbol ester activation of human uPA promoter in mouse Sertoli cells.
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PMID:Follicle-stimulating hormone and cyclic AMP induce transcription from the human urokinase promoter in primary cultures of mouse Sertoli cells. 217 96

Pro-opiomelanocortin-derived peptides, alpha-MSH and beta-endorphin, are synthesized and secreted by Leydig cells, and are believed to have paracrine effects on Sertoli cells in the testis. Peptides with MSH activity stimulate adenylate cyclase and cAMP accumulation in Sertoli cell-enriched cultures. The purpose of the present study was to determine whether such peptides would affect Sertoli cell parameters, such as aromatase and plasminogen activator activities, that are known to be regulated by cAMP. alpha-MSH stimulated aromatase activity in Sertoli cell-enriched cultures prepared from 10-day-old rats and this effect was potentiated by methyl isobutylxanthine (MIX). The combination of alpha-MSH plus MIX was not as potent as FSH. alpha-MSH, des-acetyl-alpha-MSH, beta-MSH, ACTH(1-13), and ACTH(1-24) stimulated aromatase activity to a similar extent, suggesting that Sertoli cells do not distinguish between the activities of these peptides. alpha-MSH potentiated the action of dbcAMP and forskolin on Sertoli cell aromatase, but unexpectedly had no effect on the action of either half-maximal or maximal doses of FSH. The regulation of plasminogen activator was examined next; urokinase was markedly suppressed by FSH in 10-day-old Sertoli cells. Although neither alpha-MSH nor MIX alone had an effect on urokinase secretion, in combination they were as effective as FSH. In 10-day-old Sertoli cells each of these peptides had little or no effect on tissue plasminogen activator.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Estradiol and plasminogen activator secretion by cultured rat Sertoli cells in response to melanocyte-stimulating hormones. 247 57

The secretion of plasminogen activator by seminiferous tubules at defined stages of the epithelial cycle is influenced both by neighboring spermatogenic cells and by hormones. We have used cRNA probes for urokinase-type (uPA) and tissue-type (tPA) plasminogen activators to analyze their mRNA levels in different stages of the epithelial cycle. Urokinase-type PA mRNA was most abundant in stages VII-VIII, while tPA mRNA levels showed smaller variations between the different stages. Both FSH and (Bu)2cAMP increased the steady-state level of tPA mRNA and tPA production without affecting those of uPA in stages VII-IX in vitro, whereas retinoic acid treatment selectively increased the concentration uPA mRNA and uPA production in stages II-VI. The results show that the expression of the uPA and tPA genes is differentially regulated in specific stages of the rat seminiferous epithelium.
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PMID:Regulation of urokinase- and tissue-type plasminogen activator gene expression in the rat seminiferous epithelium. 253 92

We studied the direct effects of glucocorticoids on plasminogen activator (PA) production by rat granulosa cells. PA production was assayed by culturing rat granulosa cells on [125I]fibrin plates and determining the extent of fibrinolysis after addition of the specific substrate plasminogen. In granulosa cells from preantral follicles of immature rats, treatment with FSH caused dose-dependent increases in PA production whereas glucocorticoids by itself was without effect. Increasing concentrations (10(-10) to 10(-6) M) of both natural and synthetic glucocorticoids potentiated the stimulating effect of FSH on PA production by 120 to 170%. The stimulatory potencies of the natural corticosteroids correlated with the glucocorticoid potencies (cortisol/corticosterone greater than aldosterone/11-deoxycorticosterone). In granulosa cells from Graafian follicles of mature rats, glucocorticoids on its own had direct stimulating effect on PA production. The stimulatory action of glucocorticoids on FSH-dependent PA production was completely blocked by simultaneous treatment with antiglucocorticoid RU 486. Antiserum directed against tissue-type PA (tPA) neutralized the increased fibrinolytic actions of glucocorticoids. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fibrin autography techniques, we showed that the increase in fibrinolytic activity in response to glucocorticoids resulted from increased production of tPA rather than urokinase-like PA. The effect of glucocorticoids on the production of PA inhibitors (PAI) was examined by 1) neutralization of urokinase activity by increasing amounts of culture media from granulosa cells treated with glucocorticoids, 2) reverse fibrin autography, and 3) Western blot analysis with a specific PAI antiserum. All these methods failed to detect a stimulatory action of glucocorticoids, with or without FSH, on PAI production by rat granulosa cells in the culture media. Our data showed that glucocorticoids have a direct stimulating effect on tPA production, but unlike its action on other in vitro systems, they have no significant effect on PAI production by rat granulosa cells in vitro.
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PMID:Glucocorticoids stimulate plasminogen activator production by rat granulosa cells. 278 80

The cyclic secretion of plasminogen activator (PA) by Sertoli cells in stages VII and VIII of the rat seminiferous epithelial cycle is influenced by hormones and adjacent spermatogenic cells. To understand this interaction more in detail, we have analyzed the effects of FSH, (Bu)2cAMP, testosterone, insulin, and retinoic acid (RA) on staged seminiferous tubule segments in vitro. FSH stimulated stages VIIcd to XI of the cycle; similar results were obtained with (BU)2cAMP. RA stimulated PA secretion in stages I-VIIab, but testosterone and insulin had no effect in any stage. The secreted PA was mainly of the urokinase type, although small amounts of the tissue-type PA were found after stimulation by FSH and cAMP. These results suggest that spermatogenic cells modify the responsiveness of Sertoli cells to hormonal stimulation. Stages I-VIIab are sensitive to stimulation by RA whereas stages VIIcd-XI are preferentially stimulated by FSH and (Bu)2cAMP.
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PMID:Stage-specific regulation of plasminogen activator secretion in the rat seminiferous epithelium. 302 24

The hormonal induction and immunological reactivities of the cell-associated plasminogen activators (PAs) produced by granulosa cells obtained from the ovaries of diethylstilbestrol-implanted immature rats were studied. FSH and other cAMP-inducing ligands, including cholera toxin, forskolin, and 8-bromo-cAMP, elevated the PA activity of granulosa cells in a concentration-dependent manner during a 4-h culture, with an approximate 10-fold maximal increase in PA activity compared to control cells. Negligible levels of PA activity were observed in the extracellular medium in the absence or presence of hormones. The PA induced by FSH or cAMP in intact cells was progressively neutralized during the 4-h culture by increasing amounts of antibodies to the tissue-type PA (tPA), but not by an IgG fraction against the urokinase-type PA (UK-PA). However, solubilization of granulosa cells with Triton X-100 revealed the presence of intracellular UK-PA activity in both FSH-treated and control cells that consisted of about 20% of the total cellular PA activity. Electrophoretic analysis of extracts from solubilized granulosa cells indicated the presence of three peaks of PA activity. A PA with a Mr of 70,000 was induced by FSH, was completely inactivated by tPA antibodies, and required fibrin for full activity. A 40,000 Mr fibrin-independent PA was also stimulated by FSH and was partially inhibited by UK-PA antibodies, but not by anti-tPA immunoglobulin G. A third peak of PA activity comigrated with a human UK-PA standard at a Mr of 33,000, was fully neutralized by UK-PA antibodies, and was largely present only in control cells. These results suggest that during the first hours of granulosa cell development, FSH via cAMP induces the production of a cell-surface tPA, while both FSH-treated and control cells synthesize intracellular UK-PAs. Hormonal regulation of the production and activities of these cellular enzymes may allow the expression of specific differentiated functions of developing granulosa cells.
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PMID:Hormonal and immunological characterization of the cell-associated plasminogen activators produced by cultured rat granulosa cells. 303 77

Plasminogen activators convert plasminogen into plasmin, a serine protease that initiates extracellular proteolysis. Two types of plasminogen activator activities have recently been demonstrated in granulosa cells, and the proteolysis-inducing enzymes are believed to be involved in ovulation. However, little attention has been paid to the presence of these enzymes in oocytes. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by a fibrin overlay technique, we studied plasminogen activator activity in oocytes. Denuded oocytes collected from ovaries of hypophysectomized, estrogen-treated immature rats contained a tissue-type plasminogen activator (tPA), but not urokinase (uPA). In contrast, oocyte-free granulosa cells in these preantral follicles contained uPA, but not tPA. The tPA activity found in oocytes was plasminogen-dependent; incubation with increasing numbers (25-200) of denuded oocytes resulted in a dose-dependent increase in fibrinolysis only in the presence of plasminogen. Cellular localization of tPA was studied in the preantral follicles using an immuno-cytochemical method. Positive tPA staining was detected in the cytoplasm, but not in the germinal vesicle or zona pellucida of the oocytes. Furthermore, analysis using a reverse fibrin-overlay method did not reveal the presence of a plasminogen activator inhibitor. Culturing of denuded oocytes for 24 h increased the cellular content of tPA, but the enzyme activity was not further enhanced by treatment with FSH or forskolin. Also, no tPA activity was detected in the medium. We further studied plasminogen activator activities in the cumulus-oocyte complexes. Although only tPA activity was detected in freshly obtained cumulus-oocyte complexes, incubation for 24 h increased both tPA and uPA activity. Furthermore, tPA, but not uPA, activity was stimulated by treatment with FSH or forskolin. This was accompanied by the secretion of tPA into the medium. The identity of tPA and uPA in the cumulus-oocyte complexes was further confirmed by immunoprecipitation with specific antibodies. Isolation of denuded oocytes and cumulus cells after hormonal stimulation of the cumulus-oocyte complexes suggested that tPA activity was stimulated in both cell types and that the cumulus cells may mediate the action of FSH and forskolin on oocytes. In conclusion, the detection and regulation of tPA activity in cumulus-oocyte complexes suggest possible involvement of this enzyme in ovulation or the process of cumulus cell expansion and dispersion. Changes in oocyte tPA content may also serve as an indicator of oocyte development.
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PMID:Identification and regulation of tissue plasminogen activator activity in rat cumulus-oocyte complexes. 309 95

Two molecular variants of plasminogen activator (PA): urokinase (uPA) and tissue-type plasminogen activator (tPA), have been reported to be synthesized in the rat testis. Data obtained in this study using monospecific antibodies raised against uPA and tPA in immunoblotting and bioimmunoassay protocols consistently demonstrate that only tPA (and not uPA) is synthesized by bovine Sertoli cell-enriched cultures, and is induced by bovine FSH. Zymographic analysis of conditioned medium on gels containing plasminogen and casein showed a dominant PA proteolytic band (72 kDa) which co-migrated with human tPA. A proteolytic band (43 kDa), which was also secreted by FSH-stimulated cells, was not present when protection was afforded from auto-proteolysis by aprotinin, and was therefore concluded to be a proteolytic fragment of tPA, and not uPA.
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PMID:Only tissue-type plasminogen activator is secreted by immature bovine Sertoli cell-enriched cultures. 312 22


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