Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.68 (tissue plasminogen activator)
 11,311 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracellular matrix (ECM) plays an important role in the maintenance of mammary epithelial differentiation in culture. We asked whether changes in mouse mammary specific function in vivo correlate with changes in the ECM. We showed, using expression of beta-casein as a marker, that the temporal expression of ECM-degrading proteinases and their inhibitors during lactation and involution are inversely related to functional differentiation. After a lactation period of 9 d, mammary epithelial cells maintained beta-casein expression up to 5 d of involution. Two metalloproteinases, 72-kD gelatinase (and its 62-kD active form), and stromelysin, and a serine proteinase tissue plasminogen activator were detected by day four of involution, and maintained expression until at least day 10. The expression of their inhibitors, the tissue inhibitor of metalloproteinases (TIMP) and plasminogen activator inhibitor-1, preceded the onset of ECM-degrading proteinase expression and was detected by day two of involution, and showed a sharp peak of expression centered on days 4-6 of involution. When involution was accelerated by decreasing lactation to 2 d, there was an accelerated loss of beta-casein expression evident by day four and a shift in expression of ECM-remodeling proteinases and inhibitors to a focus at 2-4 d of involution. To further extend the correlation between mammary-specific function and ECM remodeling we initiated involution by sealing just one gland in an otherwise hormonally sufficient lactating animal. Alveoli in the sealed gland contained casein for at least 7 d after sealing, and closely resembled those in a lactating gland. The relative expression of TIMP in the sealed gland increased, whereas the expression of stromelysin was much lower than that of a hormone-depleted involuting gland, indicating that the higher the ratio of TIMP to ECM-degrading proteinases the slower the process of involution. To test directly the functional role of ECM-degrading proteinases in the loss of tissue-specific function we artificially perturbed the ECM-degrading proteinase-inhibitor ratio in a normally involuting gland by maintaining high concentrations of TIMP protein with the use of surgically implanted slow-release pellets. In a concentration-dependent fashion, involuting mammary glands that received TIMP implants maintained high levels of casein and delayed alveolar regression. These data suggest that the balance of ECM-degrading proteinases and their inhibitors regulates the organization of the basement membrane and the tissue-specific function of the mammary gland.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Coordinated expression of extracellular matrix-degrading proteinases and their inhibitors regulates mammary epithelial function during involution. 151 97

Recent studies have indicated that neutral collagenase can be produced in bones of rats. In addition, it has been demonstrated by in vitro studies that the enzyme is likely secreted by osteoblasts. Cells of the osteoblastic tumor cell line UMR-106 can be stimulated to produce not only collagenase, but also collagenase inhibitor and plasminogen activator. However, it is conceivable that not all osteoblasts produce all of these proteins. In this study, in which UMR cells were maximally stimulated with PTH, only a subpopulation of cells was observed to produce enhanced levels of collagenase but all cells had the ability to synthesize plasminogen activator. Cells of the rat osteosarcoma line UMR-106-01 were stained for the presence of collagenase and tissue plasminogen activator using an immunohistochemical procedure. In many cases, the cells were exposed to monensin for the final 3 h of incubation as well as to the inducing agent PTH. Monensin prevented export of the enzymes, enabling them to be visualized within their cell or origin. Maximal stimulation of collagenase was demonstrated to occur 8 h after exposure to 10(-8) -10(-7) M PTH. Under these conditions, 14-17% of the cells appeared to synthesize elevated amounts of collagenase (as determined by intense staining). Without PTH stimulation, there was a low level of collagenase in all cells, but less than 1% of the cells stained heavily for the enzyme. In contrast, strong staining for plasminogen activator was observed in all cells with or without PTH treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Stimulation of collagenase production by rat osteosarcoma cells can occur in a subpopulation of cells. 217 54

To understand the mechanisms regulating osteoid removal by osteoblasts, mouse calvarial osteoblasts were grown on 14C-labelled type I collagen films and stimulated with 1,25-dihydroxyvitamin D-3 (2.5.10(-8) M) for 48-72 h. In the presence of 5% non-inhibitory rabbit serum this resulted in a 2-3-fold increase in collagen degradation and a dramatic change in osteoblast morphology, when compared with untreated osteoblasts. Collagenolysis was accompanied by increased synthesis and release of latent collagenase, gelatinase and stromelysin and a concomitant decrease in their specific inhibitor, TIMP (tissue inhibitor of metalloproteinases). In serum-free medium, osteoblasts failed to degrade collagen, but their ability to lyse collagen could be restored by adding plasminogen (5 micrograms/ml) to the cultures. Plasminogen-dependent collagenolysis was inhibited by human recombinant TIMP (5 units/ml), demonstrating that plasmin, derived from plasminogen, activated latent collagenase and did not itself degrade collagen. Plasminogen activator production was confirmed by culturing osteoblasts on 125I-labelled fibrin plates. Comparison with urokinase-type and tissue-type plasminogen activator standards suggested that osteoblast plasminogen activator was predominantly cell-associated and likely to be of the urokinase type. Immunocytochemistry indicated that osteoblasts also constitutively produce plasminogen activator inhibitor-1. These findings provide evidence for the involvement of a plasminogen-plasmin-latent metalloproteinase activation cascade in type I collagen degradation by osteoblasts, and for its regulation by TIMP and plasminogen activator inhibitor-1.
 ...
PMID:Type I collagen degradation by mouse calvarial osteoblasts stimulated with 1,25-dihydroxyvitamin D-3: evidence for a plasminogen-plasmin-metalloproteinase activation cascade. 255 72

Matrix-degrading proteinases secreted by tumor cells play crucial roles in tumor cell invasion and metastasis. Serum-free conditioned media of 7 human gynecological carcinoma cell lines were examined for proteinases and their inhibitors by using gelatin zymography, reverse zymography and immunoblotting. All of three ovarian adenocarcinoma cell lines secreted urokinase-type plasminogen activator. Among them, a mucinous cystadenocarcinoma cell line also secreted tissue-type plasminogen activator, plasmin-like enzyme and trypsinogen. On the other hand, two ovarian undifferentiated carcinoma cell lines mainly secreted glatinase A or B. A choriocarcinoma cell line secreted multiple metalloproteinases in the highest amount, whereas an endometrial adenocarcinoma cell line (HEC-1) derived from an early clinical stage hardly secreted any gelatinolytic enzyme. The five high proteinases producers hardly secreted the corresponding inhibitors, such as tissue inhibitor of metalloproteinases (TIMP)-1, -2 or plasminogen activator inhibitor-1. In contrast to these highly malignant cell lines, a poor proteinase producer, HEC-1, secreted a large amount of TIMPs. Therefore, an enhanced proteolytic tendency appears to be associated with gynecological cancer cells established from highly malignant tumors.
 ...
PMID:Characterization of matrix-degrading proteinases and their inhibitors secreted by human gynecological carcinoma cells. 762 22

A rapid and sensitive method for sequencing oligosaccharides has been developed, using matrix-assisted laser desorption mass spectrometry to monitor the digestion of glycopeptides by specific exoglycosidases. Recombinant human tissue inhibitor of metalloproteinases (TIMP), which has two glycosylation sites, has been characterized to illustrate this new approach for obtaining site-specific information. Glycopeptides which span residues Asn30 and Asn78 were generated by tryptic digestion of 1 nmol of TIMP and separated by reverse-phase high-performance liquid chromatography. The oligosaccharide composition of the glycoforms was inferred from the observed mass shifts following digestion by peptide-N-glycosidase F. Composition and sequence were then elucidated by digestion with specific exoglycosidases, using a total of 200 pmol of each glycopeptide. Glycopeptides from well-characterized proteins, fetuin, alpha 1-acid glycoprotein, and tissue plasminogen activator were also analyzed to confirm exoglycosidase specificity for glycopeptides and establish the quantitative significance of the relative intensities of peaks in the mass spectra. Both TIMP glycosylation sites exhibited extensive heterogeneity comprising mainly fucosylated complex oligosaccharides, but in different proportions. The Asn78 site also contained 4.4% nonfucosylated mannose (Man4) oligosaccharide. The merits and limitations of this approach as a universal method for oligosaccharide analysis are discussed.
 ...
PMID:Site-specific characterization of glycoprotein carbohydrates by exoglycosidase digestion and laser desorption mass spectrometry. 805 66

An in vitro system has been established in which conversion from non-metastasizing to metastasizing adenocarcinoma cells can be induced, and subsequently subjected to analysis of the expression of proteases and tissue inhibitor of metalloproteinases-1 (TIMP-1). A human salivary-gland adenocarcinoma cell clone HSGc, with no metastatic ability, was exposed to N-methyl-N-nitrosourea (MNU). Following exposure to MNU, cells with altered morphology were cloned. Upon s.c. inoculation into nude mice, MNU-treated HSGc clones formed metastatic foci in various organs, and then 5 metastasizing clones were isolated. Evaluation of expression of tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), metalloproteinases and TIMP-1 was performed by means of enzyme immunoassay, zymogram, or immunoblot. MNU-treated HSGc and metastasizing clones were found to secrete high levels of tPA, while HSGc produced undetectable levels of this enzyme. Expression of uPA was not observed in any of the cell clones. When the secretion of gelatinolytic enzymes was examined, metastasizing clones produced higher levels of 57- and 32-kDa, but not of 92- or 72-kDa gelatinases, as compared to HSGc cells. Although TIMP-1 was detected in all cell clones, metastasizing clones secreted less TIMP-1 than HSGc cells; in addition, one metastasizing clone produced TIMP-1 with a molecular weight distinct from that of 28-kDa TIMP-1. Our results suggest that the acquisition of metastatic ability by human salivary-gland tumor cells is closely associated with increased secretion of several metalloproteinases as well as decreased or altered TIMP-1 expression.
 ...
PMID:Role of plasminogen activators, metalloproteinases and the tissue inhibitor of metalloproteinase-1 in the metastatic process of human salivary-gland adenocarcinoma cells. 851 58

The cellular events causing pathological extracellular matrix (ECM) accumulation in vivo are not well understood. Prolonged serial passage of several cell types in culture leads to increased production of extracellular matrix (ECM) proteins, but the mechanism for these putative fibrotic changes is not known. Here, human fetal glomerular mesangial cells were subjected to serial passage (P) in culture and the expression of ECM proteins, proteases and protease inhibitors was comprehensively evaluated. From P11 through P14, a series of phenotypic changes occurred. Steady-state expression of mRNA for alpha 1 chains of type III and type IV (but not type I) collagen, and for laminin beta 1 and gamma 1, increased 2- to 8-fold, while expression of mRNA for interstitial collagenase (MMP-1) and gelatinase A (MMP-2) virtually ceased. Expression of tissue-type plasminogen activator (tPA) mRNA also decreased markedly. Expression of mRNA for the tissue inhibitor of metalloproteinases (TIMP)-1, and of the smaller of two mRNA species for the PA inhibitor PAI-1, ceased by P14. There was a switch in expression of the two species of TIMP-2 mRNA: whereas the ratio of signal intensity comparing the 3.5 kb mRNA species to the 1.0 kb species was 5:1 up to P11, it was reversed (1:5) at P14 and later. Serial passage also led to changes in protein expression, with increased type IV collagen and laminin, but decreased interstitial collagenase and gelatinase A. The cells showed a progressive increase in staining for type IV collagen. These findings define the appearance of a matrix-accumulating phenotype in later-passage mesangial cells. Matrix expansion in vivo has been associated with increased transforming growth factor (TGF)-beta synthesis; the cells were found to show at least 5-fold increased expression of TGF-beta 1 mRNA from P8 to P16. However, treatment of P9 or P10 cells with graded doses of TGF-beta 1 increased expression of both collagen IV and gelatinase A mRNA and did not alter the ratio of signal intensity for TIMP-2 mRNA species. Thus, assumption of a matrix-accumulating phenotype by these cultured fetal glomerular mesangial cells is not accelerated by exogenous TGF-beta. These data describe an in vitro model of mesangial cell matrix turnover in which matrix accumulation could result from a concerted increase in ECM synthesis and decrease in ECM degradation.
 ...
PMID:Increased expression of extracellular matrix proteins and decreased expression of matrix proteases after serial passage of glomerular mesangial cells. 892 13

Although heart attack is caused by occlusion of a major coronary artery, some patients have occlusion without heart attack because these patients have sufficient collateral circulation to provide an alternate pathway for blood supply to the myocardium at ischemic risk. The growth of new capillary vessels (angiogenesis) and enlargement of preexisting vessels play an important role in the collateral development. We evaluated the hypothesis that extracellular matrix metalloproteinase (MMP) expression is altered in coronary collateral arteries (0.5-1 mm o.d.) isolated from canine hearts 2-4 months after surgical placement of an ameroid occluder around the proximal left circumflex artery (n = 4), during the development of collateral vessels and restructuring new vessels. Histologic studies (hematoxylin and eosin, trichrome, and van Gieson stains) indicated cellular proliferation and increased collagen and elastin content in collateral vessels compared with comparable-sized unoccluded arterial segments of the left anterior descending (LAD) artery. In situ MMP activity of collateral vessels, measured using denatured collagen in the gel matrix, indicated an increase in total MMP activity in the intima of collateral vessels compared with normal LAD vessels. To further identify the type of MMP, tissue homogenates were prepared from collateral and LAD vessels and analyzed by SDS-PAGE zymography. The results suggest induction of gelatinase A and gelatinase B expression in collateral vessels compared with normal LAD tissue, when identical amounts of total protein were loaded onto each lane in the gel. Based on plasminogen-casein zymography, we observed the tissue plasminogen activator level to be increased in collateral vessels. On the basis of immunoblot and mRNA (Northern blot) analyses, we determined that the MMP-1 level was induced in collateral vessels 2 and 4 months after ameroid occlusion. In contrast with MMP-1, the level of TIMP-1 (tissue inhibitor of metelloproteinases) was decreased significantly (p < 0.001) in collateral compared with LAD vessels, suggesting a role for arterial TIMP in anti-angiogenic activity. Collectively, these results suggest that chronic occlusion of a major coronary artery induces upregulation of vascular remodeling mechanisms subserving collateral development. Increased MMP-2 activity in collaterals may be associated with decreased levels of tissue inhibitor of metalloproteinases and fibrous tissue remodeling following angiogenic and (or) adaptive responses of the myocardium to chronic ischemia.
 ...
PMID:Temporal expression of extracellular matrix metalloproteinases and tissue plasminogen activator in the development of collateral vessels in the canine model of coronary occlusion. 896 Mar 89

We report on the effect of prolonged hyperglycaemic (11 and 30 mM D-glucose) culture conditions on human mesangial cell matrix metalloproteinases (MMPs), plasminogen activators and their inhibitors. The results indicate that hyperglycaemic conditions modulate the potential proteolytic activity of the enzymes secreted by confluent cultures of these cells. Gelatinase A (MMP-2) activity was always higher in cultures maintained under hyperglycaemic than under normoglycaemic conditions (4 mM D-glucose). In contrast, gelatinase B (MMP-9) activity was decreased under the same conditions. Matrilysin (MMP-7) activity was decreased by up to 100% under hyperglycaemic conditions. Reverse transcriptase-PCR and Western-blotting analyses indicate that in all cases both the transcripts and the protein level were correlated with enzymic activity. One tissue inhibitor of metalloproteinases, TIMP-2, was barely detectable under hyperglycaemic conditions (30 mM D-glucose). In contrast, TIMP-1 increased during the initial 2 weeks of culture in hyperglycaemic conditions and remained elevated to the end of the experiment (4 weeks). Under normoglycaemic conditions TIMP-1 decreased after 2 weeks of culture. Hyperglycaemic conditions also decreased markedly the activity of tissue plasminogen activator (t-PA). This seemed to be due to increased synthesis of its inhibitor, plasminogen activator inhibitor 1, under these conditions rather than to decreased expression of the t-PA enzyme.
 ...
PMID:Modulation of neutral protease expression in human mesangial cells by hyperglycaemic culture. 900 62

Wound healing is a complex process involving the interactions of many different cell types, matrix components and biological factors, including proteinases and cytokines. This study compared the levels of proteinases (matrix metalloproteinases and plasminogen activators), proteinase inhibitors (tissue inhibitors of metalloproteinases and plasminogen activator inhibitors), inflammatory cytokines and growth factors in acute wound fluid samples collected from the surgical drains of elective breast (n = 24) and colorectal (n = 26) patients on the first postoperative day. Gelatin zymography was used to determine matrix metalloproteinase-2 and -9 levels, quenched fluorescence substrate hydrolysis was applied for total MMP activity and enzyme-linked immunoassays were used to quantitate other factors. Colorectal wound fluid samples showed significantly (p < 0.05) greater levels of the matrix metalloproteinases (MMP-1, 2, 3, and 9), tissue inhibitor of metalloproteinases-1, urokinase plasminogen activator receptor and the inflammatory cytokines (interleukin-1beta, -6, and tumor necrosis factor-alpha); e.g., matrix metalloproteinase-3 colon; median 275 (range 11-2.530) ng/ml; breast; 530-400. However, tissue plasminogen activator and growth factor levels (epidermal growth factor, platelet-derived growth factor, basic fibroblast growth factor, transforming growth factor-beta1) were significantly greater in breast samples; e.g., epidermal growth factor breast 468 (103-1, 444) pg/ml; colon 57(1-573). There was no difference in the levels of urokinase type plasminogen activator, plasminogen activator inhibitor-1 and -2, tissue inhibitor of metalloproteinases -2 or vascular endothelial growth factor. Acute wound fluid from different surgical wounds showed different profiles of proteinases, proteinase inhibitors, and cytokines. This may lead to differences in the rate of tissue remodeling and therefore healing in these two wounds in vivo.
 ...
PMID:Proteinases, their inhibitors, and cytokine profiles in acute wound fluid. 1111 51


1 2 Next >>