Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The progestin medroxyprogesterone acetate (MPA) enhanced expression of the endothelial-type plasminogen activator inhibitor PAI-1 by stromal cells from cycling endometrium and by decidual cells from first trimester endometrium. In the cultured stromal cells, Northern analysis revealed a 4-fold increase in steady state levels of PAI-1 mRNA in response to 10(-6)-10(-8) mol/L MPA. Although the cells were refractory to 10(-8) mol/L estradiol (E2) alone, E2 plus MPA produced a further doubling of PAI-1 mRNA levels. Parallel effects on PAI-1 protein levels in the stromal cell-conditioned medium were measured by immunoassay and confirmed by immunoblot analysis. During an initial 3-day exposure, PAI-1 levels were elevated 6- and 12-fold by MPA and E2 plus MPA, respectively, compared with those in either control or E2-treated cells. In the subsequent 3 days of culture, PAI-1 levels were increased 30-fold by MPA and 70-fold by E2 plus MPA. Cultured decidual cells released significant quantities of PAI-1 under basal conditions; these levels were also elevated by MPA and increased markedly by E2 plus MPA. While PAI-2 was also detected in both stromal and decidual cell cultures, its levels were far lower than those of PAI-1 and were unaffected by exogenous steroids. Extrapolation of these in vitro results to periimplantational events in humans suggests that under progesterone regulation, decidual cell-derived PAI-1 could 1) restrain blastocyst invasion of the stroma by inhibiting trophoblast-associated urokinase-type plasminogen activator, and 2) prevent hemorrhage during trophoblast invasion of the endometrial vasculature by inhibiting fibrinolysis mediated by tissue-type plasminogen activator.
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PMID:Progestin regulation of plasminogen activator inhibitor type 1 in primary cultures of endometrial stromal and decidual cells. 837 Jun 84

The type of plasminogen activator (PA) produced by Day 7, 9, and 11 ovine embryos in vitro was partially characterized. PA activity in the conditioned medium did not change (p > 0.05) up to equivalent gestational Day (EGD) 14 but increased to peak levels on EGD 15 (p < 0.05). Zymographic analysis of conditioned medium and embryos revealed one plasminogen-dependent lytic zone (48-51 kDa) within EGD 8-15 and a second plasminogen-dependent lytic zone that appeared after EGD 13 (79-83 kDa). Addition of the urokinase competitive inhibitor, amiloride, to the zymograph inhibited plasminogen-dependent lytic activity; and forms of both high and low molecular mass were immunoprecipitated with antiserum to bovine urokinase-type PA. PA activity in conditioned medium was completely suppressed by amiloride treatment (p < 0.05) but was increased (p < 0.05) after incubation with antibodies to human PA inhibitor (PAI)-2. Treatment with antibodies to human PAI-1 did not increase (p > 0.05) PA activity in conditioned medium. These results suggest that Day 7, 9, and 11 ovine embryos produce a urokinase-type PA (49.9 +/- 0.5 kDa) and possibly a PAI-2-like protein that associates with the PA and forms a PA-PAI complex of high molecular mass (81.4 +/- 1.2 kDa).
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PMID:Partial characterization of the plasminogen activator produced by ovine embryos in vitro. 837 64

Plasminogen activators and their inhibitors have been implicated in the process of fibrinolysis, tissue remodeling, and ovulation. Epidermal growth factor (EGF), a paracrine hormone found in the human ovary, increases plasminogen activator (PA) activity and the gene expression of PA and plasminogen activator inhibitor (PAI) in human endothelial cells and human cell lines. Gonadotropins also increase PA activity and gene expression in rat preovulatory granulosa cells. We have now analyzed the gene expression of PAI-1 and PAI-2 in uncultured human cumulus cells (CC), uncultured granulosa-luteal cells (GLC), and cultured GLC obtained from preovulatory follicles of patients undergoing assisted reproductive technologies. We also studied the effects of hCG and EGF on PAI-1 and PAI-2 mRNA levels in cultured GLC; GLC were cultured in serum-free medium for various times within 24 h with or without hCG and for 6 h with or without hCG, EGF, or EGF plus hCG. Total RNAs from CC and GLC were extracted, and blot hybridizations with 32P-labeled PAI-1, PAI-2, or 28S ribosomal RNA cDNA probes were performed. Both CC and GLC expressed PAI-1 and PAI-2 genes. In GLC, steady state levels of PAI-1 mRNA levels steadily increased within 24 h of culture, whereas PAI-2 levels peaked at 6 h of culture. PAI-1 mRNA levels were not affected by hCG or EGF at 6 h of culture, but PAI-2 mRNA levels were significantly increased by EGF at 6 h of culture. These studies demonstrate that human GLC PAI-1 and PAI-2 mRNA levels are differentially regulated and suggest that EGF may be involved in modulation of the human ovarian PA system during the periovulatory period.
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PMID:Regulation of plasminogen activator inhibitor-1 and -2 messenger ribonucleic acid levels in human cumulus and granulosa-luteal cells. 843 98

The plasminogen activator (PA)/plasminogen activator inhibitor (PAI) system is believed to be involved in connective tissue remodelling in joint disease and both PA and PAI production has been shown in several cell types in the joint. We quantified immunoreactive PA and PAI in synovial fluid (SF) and correlated their levels to levels of cartilage derived proteoglycans, radiologically visible joint involvement and to signs of local inflammation. PAI-2 concentrations were increased, compared to normal plasma levels, in patients with rheumatoid arthritis (RA) and reactive arthritis, but not in patients with osteoarthritis (OA). Thirty percent of the patients with RA, but no patient with OA had increased concentrations of PAI-1. Increased concentrations of urokinase type PA (u-PA) were found in RA but not in OA. Tissue type PA (t-PA) concentrations were low in both disease groups. SF proteoglycan concentrations did not correlate with levels of PA or PAI. Concentrations of PAI-2 correlated significantly with SF leukocyte count and cytidine deaminase (CD) activity and u-PA concentrations correlated with CD activity. Both PAI-2 and u-PA were detected in supernatants from lysed polymorphonuclear cells. This suggests that in addition to release from synovial cells and chondrocytes these components may also be released from polymorphonuclear cells. Our results support a pathophysiological role for the fibrinolytic system in joint disease, possibly more pronounced in inflammatory disorders than in OA.
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PMID:Plasminogen activators and plasminogen activator inhibitors in synovial fluid. Difference between inflammatory joint disorders and osteoarthritis. 844 Nov 74

Plasminogen activators are inhibited by plasminogen activator inhibitors-1 (PAI-1) and -2 (PAI-2). We describe the synthesis of PAI-2 by human vascular endothelial cells (EC) cultured from umbilical vein, saphenous vein and foreskin microvasculature in response to interleukin-1 alpha (IL-1 alpha) and tumour necrosis factor alpha (TNF alpha) and compare it with that of PAI-1. Both PAI-2 and PAI-1 were quantitated by ELISAs. PAI-2 was cell-associated while PAI-1 was secreted by EC. IL-1 alpha and TNF alpha increased the synthesis of PAI-2 and PAI-1 by EC in a dose-dependent manner. IL-1 alpha was a stronger stimulus for PAI-2 synthesis than TNF alpha, while both cytokines were equally effective for PAI-1. Northern blot analysis revealed similar changes in mRNA levels to those in antigen levels. PAI-2 synthesis by cytokine-stimulated EC may be important in thrombus formation and inflammation.
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PMID:Cytokine regulation of the synthesis of plasminogen activator inhibitor-2 by human vascular endothelial cells. Comparison with plasminogen activator inhibitor-1 synthesis. 845 26

This study delineates the regulatory effect of interleukin-1 (IL-1) and interleukin-2 (IL-2) on monocyte plasminogen activator (PA) activity. Mononuclear phagocytes regulate net PA activity by modulating the expression of urokinase-type PA (uPA) and a specific plasminogen activator inhibitor, PAI-2. To understand the regulation of mononuclear phagocyte PA activity, it is important to compare the expression of uPA and PAI-2. In this study, we determined the relative abundance of secreted PA and PA inhibitor activity in human monocyte-conditioned medium after stimulation with human recombinant IL-1 or IL-2. In agreement with our previous description of tumor necrosis factor-alpha and interferon-gamma stimulation of mononuclear phagocytes, we found no detectable PA activity in conditioned medium. Both IL-1 and IL-2 had dose-dependent effects, significantly up-regulating PA inhibitor activity in monocyte-conditioned medium (up to 11-fold). To further investigate the mechanism underlying this effect, Northern blot analysis was done to measure steady-state mRNA for uPA and PAI-2. Consistent with the increase in secreted PA inhibitor activity, we found that both IL-1 and IL-2 significantly increased steady-state mRNA for PAI-2. In addition, however, both IL-1 and IL-2 increased steady-state mRNA for uPA. IL-1 appears to increase mRNA for uPA to a greater extent than does IL-2. We conclude that IL-1 and IL-2 modulate monocyte proteolytic activity by increasing expression of uPA and PAI-2 with a resultant predominance of PAI-2. We further conclude that cytokine-specific regulation of plasminogen activity is achieved partly by varying the proportionate expression of uPA and PAI-2.
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PMID:Monocyte urokinase expression: modulation by interleukins. 850 98

Disturbances in the regulation of the balance between the fibrinolytic and procoagulant properties of leukemic cells may contribute to the coagulopathy of acute leukemia. The coagulant response to a number of stimuli is regulated by the expression of tissue factor, but the role of the plasminogen activator inhibitors, PAI-1 and PAI-2, in contributing to the net coagulant response is not known. In this study, we have examined the production of these proteins by cultured myeloid leukemic cells arrested at different stages of differentiation. Northern blot analysis showed time-dependent and differential production of mRNA for PAI-2 and tissue factor, and to a much lesser extent, PAI-1, in response to the differentiating agent, 12-phorbol-13-myristate acetate. The capacity to synthesize PAI-2 appeared to be related to the stage of myeloid cell differentiation. Examination of the gene products by immunoblot analysis demonstrated multiple forms of PAI-2 in all myeloid cells examined. In addition, a common characteristic of all the myeloid cells was the production of a high molecular weight species of tissue factor which may be a secreted form unique to leukemic cells. Taken together, the findings demonstrate that myeloid leukemic cells are capable of generating a multicomponent coagulant response.
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PMID:Tissue factor and plasminogen activator inhibitor expression in the differentiation of myeloid leukemic cells. 830 77

Plasminogen activators (PA) have been implicated with the degradation of extracellular matrix during the invasive growth of metastasising tumour cells. The significance of PA expression in tumour cells for the in vivo growth of malignant tumours is still a matter of debate. We, therefore, performed immunohistological studies on human colon tumours using monoclonal antibodies against urokinase- (u-PA) and tissue-type plasminogen activator (t-PA) as well as against plasminogen activator inhibitors 1 and 2 (PAI-1, PAI-2). Normal colorectal mucosa of seven samples was negative for all four constituents of the PA system. Tumour epithelium of 64 colorectal carcinomas and 10 liver metastases was consistently negative for both, PA and their inhibitors. However, two of four human colon carcinoma cell lines weakly expressed u-PA, PAI-1 and PAI-2. Intestinal dendritic or fibroblast-like cells within the tumour tissue strongly expressed u-PA and, at a lower level, also t-PA, PAI-1 and PAI-2. Vascular endothelial cells were weakly positive for all components of the PA system in colon carcinoma. Our findings indicate that colon carcinoma cells in their natural environment do not express constituents of the PA system. PA activity, previously found in colon carcinoma tissue, is most likely derived from interstitial cells.
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PMID:Plasminogen activators and plasminogen activator inhibitors in human colorectal carcinoma tissues are not expressed by the tumour cells. 851 31

The mechanism of thrombin induction of tissue- and urokinase-type plasminogen activator (t-PA and u-PA) biosynthesis was investigated in cultured human fetal lung fibroblast cells, IMR-90. Northern blot analysis of total RNA from thrombin-treated cells showed marked accumulations of both t-PA and u-PA mRNA during 24 h. Nuclear run-on experiments showed that the transcription rates of both genes were increased in the thrombin-treated cells. These thrombin effects were inhibited by cycloheximide (CHX), an inhibitor of protein biosynthesis. Treatment of IMR-90 cells with CHX alone caused an increase in u-PA mRNA but not in t-PA mRNA. CHX, however, did not affect the transcription rates of both genes in the cells. Thus, on-going protein synthesis is required for increased accumulations of both t-PA and u-PA mRNA by thrombin but not for the constitutive expression of u-PA gene in IMR-90 cells. Therefore, we conclude that the accumulations of t-PA and u-PA mRNA due to thrombin result mainly from increased rates of their gene transcriptions, and that this influence is exerted in part by proteins synthesized by thrombin stimulation. Thrombin also increased plasminogen activator inhibitor type-1 (PAI-1) in the levels of both antigen and mRNA more rapidly than it increased t-PA in IMR-90 cells. In conditioned medium, most of the secreted PAI-1 seemed to form a complex with t-PA. Northern blot analysis using a PAI-2 cDNA probe showed that the levels of PAI-2 mRNA were markedly increased in response to thrombin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Transcriptional regulation of tissue- and urokinase-type plasminogen activator genes by thrombin in human fetal lung fibroblasts. 858 10

Small vessel thrombosis is a prominent feature in kidneys undergoing vascular rejection. Type I and type 2 plasminogen activator inhibitors (PAI-1 and PAI-2, respectively) are known to mediate thrombosis. To examine the potential role of PAI-1 and PAI-2 in the mediation of vascular injury, the relationship and the time course of gene expression of PAI-1 and PAI-2 with the thrombotic changes in renal grafts were investigated in an unmodified rejection model in rats. Orthotopic renal transplantation was performed from Lewis to dark agouti (DA) rats and from DA to DA isografts; untreated normal rat kidneys were used as controls. The rats were killed on days 1-9 posttransplantation (n=18 in each allograft and isograft group). The grafts were analyzed by histopathology, in situ mRNA hybridization and Northern blot methods. The results show that PAM mRNA was first detected at day 4, when the thrombotic changes in the grafts were first seen, and that this relationship persisted during the time course observed to day 9. There was no detectable PAI-1 mRNA in the control groups and no PAI-2 in either group. In situ hybridization showed that PAI-1 positive cells were predominantly located in the cortical interstitium, consistent with the distribution of interstitial microthrombi. These results provide experimental evidence that the thrombotic changes in rejecting allografts are associated with the up-regulation of PAI-1 in the donor tissue, whereas PAI-2, from our results, does not seem to influence these changes. The data are consistent with a role for PAI-1 in the pathogenesis of vascular rejection.
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PMID:Up-regulation of type 1 plasminogen activator inhibitor messenger RNA with thrombotic changes in renal grafts. 860 67


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