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1

Insulin and insulin-like growth factor I exert different effects on plasminogen activator production or cell growth in the ovine thyroid cell line OVNIS.  

UK PubMed Central (United Kingdom)

Insulin and Insulin-like Growth Factor I (IGF-I) are evaluated for their capacity to affect cell proliferation and plasminogen activator (PA) activity production in an ovine thyroid cell line OVNIS. Insulin at physiological and supraphysiological doses induces cell proliferation and increases PA activity. IGF-I, which is also clearly mitogenic for these cells, surprisingly does not modulate PA activity. The results indicate that the growth promoting effect is mediated through the insulin and IGF-I receptors whereas PA activity is solely regulated via the insulin receptors.

Degryse B; Maisonobe F; Hovsépian S; Fayet G

1991-11-01

2

Hybrid plasminogen activators  

UK PubMed Central (United Kingdom)

A hybrid plasminogen activator which comprises the five kringle domains of plasminogen linked to the B-chain of t-PA or u-PA via an amino acid sequence comprising, respectively, the t-PA cleavage site between residues 275 and 276 and the cysteine residue 264 of t-PA or the u-PA cleavage site between residues 158 and 159 and the cysteine residue 148 of u-PA, or a derivative of a plasminogen activator comprising the serine protease domain of t-PA or u-PA, in which the catalytic site essential for plasminogen activator activity is blocked by a 2-aminobenzoyl group substituted in the 3- or 4-position with a halogen atom and optionally further substituted with one or more weakly electron-withdrawing or electon-donating groups, wherein the pseudo first order rate constant for hydrolysis of the derivative is in the range 6.0 x 10-5 to 4.0 x 10-4 sec-1 when measured in a buffer system consisting of 0.05M sodium phosphate, 0.1M sodium chloride, 0.01% v/v detergent comprising polyoxyethylenesorbitan monoleate having a molecular weight of approximately 1300, at pH 7.4 at 37°C.

Browne Michael Joseph Beecham Pharmaceuticals; Robinson Jeffery Hugh Beecham Pharmaceuticals; Smith Richard Anthony Godwin Beecham Pharm.; Kalindjian Sarkis Barret

3

Neutrophil proteases in plasminogen activation.  

UK PubMed Central (United Kingdom)

Leukocyte elastase and leukocyte cathepsin G degrade porcine plasminogen primarily by hydrolysis of the A447-I448 bond between kringle4 and kringle5. The rate of formation of des-kringle1-4-plasminogen is faster with elastase (k"obs greater than 10(5) mol-1 s-1) than with cathepsin G (kobs less than 300 mol-1 s-1). In contrast to elastase, leukocyte cathepsin G does not inactivate alpha 2-antiplasmin. Consequently, plasminogen activation by urokinase in the presence of alpha 2-antiplasmin is elastase-dependent, but cathepsin G does not overcome the action of alpha 2-antiplasmin. The rate-enhancing effect of fibrin(ogen) fragments in plasminogen activation by tissue-type plasminogen activator is also disabled efficiently by these proteases. It is concluded that enhancement of plasmin expression by neutrophil proteases is accounted for primarily by the action of elastase.

Machovich R; Himer A; Owen WG

1990-08-01

4

Neutrophil proteases in plasminogen activation.  

Science.gov (United States)

Leukocyte elastase and leukocyte cathepsin G degrade porcine plasminogen primarily by hydrolysis of the A447-I448 bond between kringle4 and kringle5. The rate of formation of des-kringle1-4-plasminogen is faster with elastase (k"obs greater than 10(5) mol-1 s-1) than with cathepsin G (kobs less than 300 mol-1 s-1). In contrast to elastase, leukocyte cathepsin G does not inactivate alpha 2-antiplasmin. Consequently, plasminogen activation by urokinase in the presence of alpha 2-antiplasmin is elastase-dependent, but cathepsin G does not overcome the action of alpha 2-antiplasmin. The rate-enhancing effect of fibrin(ogen) fragments in plasminogen activation by tissue-type plasminogen activator is also disabled efficiently by these proteases. It is concluded that enhancement of plasmin expression by neutrophil proteases is accounted for primarily by the action of elastase. PMID:1715763

Machovich, R; Himer, A; Owen, W G

1990-08-01

5

The effect of anti-human plasminogen monoclonal antibodies on Glu-plasminogen activation by plasminogen activators  

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Background: Human plasminogen is a plasma glycoprotein synthesized mainly in the liver. Conversion of plasminogen to plasmin by plasminogen activators is a key event in the fibrinolytic system. In this study, we investigated the effects of two anti-human plasminogen monoclonal antibodies, A1D12 and ...

M. Akrami; M. Mirshahi; K. Khajeh; H. Naderimanesh

6

The effect of anti-human plasminogen monoclonal antibodies on Glu-plasminogen activation by plasminogen activators  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Human plasminogen is a plasma glycoprotein synthesized mainly in the liver. Conversion of plasminogen to plasmin by plasminogen activators is a key event in the fibrinolytic system. In this study, we investigated the effects of two anti-human plasminogen monoclonal antibodies, A1D12 and MC2B8 on Glu-plasminogen activation in presence of u-PA, t-PA and streptokinase. Methods: Producing of Hybridoma antibodies was performed by fusion of spleen cells from BALB/C mice immunized with Glu-plasminogen and NS1 myeloma cells. Antibody binding to Human Glu-plasminogen was assessed using an ELISA assay. Activation of plasminogen was determined by measuring plasmin generation using the chromogenic substrate S-2251 and the effect of monoclonal antibodies, A1D12 and MC2B8 on plasminogen activation in solution was then evaluated. Initial rates and kinetic parameters of plasminogen activation in the presence of monoclonal antibodies were calculated. The effect of the monoclonal antibody MC2B8 on the rate of plasmin hydrolysis was measured. The effect of F(ab')2 fragment of A1D12 on u-PA catalyzed-plasminogen activation also compared with the effect of the whole antibody in this reaction. Results: ELISA assay showed that the antibodies reacted well with antigens. A1D12 increased the maximum velocity (Vmax) of plasminogen activation by each of the three plasminogen activators and MC2B8 decreased it. In all activation reactions, the KM value of plasminogen activation did not significantly change in the presence of antibody A1D12 whereas antibody MC2B8 increased the KM value of plasminogen activation by u-PA, fibrin monomer dependent t-PA and streptokinase. Monoclonal antibody MC2B8 had no significant effect on plasmin hydrolysis rate of synthetic substrate S-2251. Activation rate of plasminogen by u-PA in the lower concentration of F (ab)2 fragment of A1D12 was identical to activation in the presence of the whole antibody. Conclusion: The binding of the A1D12 F(ab) region to Glu-plasminogen increases the catalytic efficiency of plasminogen activation by plasminogen activators. Therefore, it may be useful to apply clinically A1D12 for the therapy of thromboembolic events such as myocardial infarction by humanizing the F(ab) fragment of the A1D12 antibody. Inhibition pattern of antibody MC2B8 obey the mixed type of enzyme inhibition by binding the antibody probably at, or near, the cleavage site of Glu-plasminogen.

M. Akrami; M. Mirshahi; K. Khajeh; H. Naderimanesh

2006-01-01

7

[Plasminogen activator from Agkistrodon halys halys venom  

UK PubMed Central (United Kingdom)

Plasminogen activator "Ahh-32" from Agkistrodon halys halys venom has been isolated and purified using affinity and ion-exchange chromatography. The purified enzyme consists of the single peptide-chain with molecular weigth of 32 kDa. It can convert free plasminogen into active form--plasmin. "Ahh-32" was inhibited by DFP and benzamidine. Besides, the enzyme influences significantly the activation of plasminogen by streptokinase without having effect on analogical process in case of usage of tissue tipe plasminogen activator. The obtained protein can be used as an instrument under investigation of protein-protein interactions in haemostasis system.

Karbovs'ky? VL; Levkiv MIu; Savchuk OM; Hornyts'ka OV; Volkov HL; Bukhan Ts

2006-11-01

8

The activation by staphylokinase of human plasminogen.  

UK PubMed Central (United Kingdom)

The activation of human plasminogen by a highly purified staphylokinase was investigated using casein or an active site titrant (p-nitrophenyl-p-guanidinobenzoate, NPGB) as a substrate. The reaction rate was time dependent, showing a pronounced lag period with either substrate. Saturation curve estimated from the caseinolytic assay was sigmoid, but changed to quasi-hyperbolic in the presence of pre-formed human plasmin. With NPGB, the extent of plasminogen conversion into esterolytic plasmin was directly proportional to staphylokinase concentration, and the saturation point was reached when the molar concentration of staphylokinase equaled that of plasminogen. It is concluded that staphylokinase acts stoichiometrically, forms an equimolar complex with plasminogen, and thus is not an enzyme but a modifier. Staphylokinase-activated plasminogen exhibits properties of a hysteretic enzyme.

Kowalska-Loth B; Zakrzewski K

1975-01-01

9

A synthetic peptide derived from staphylokinase enhances plasminogen activation by tissue-type plasminogen activator.  

UK PubMed Central (United Kingdom)

BACKGROUND: A synthetic nonadecapeptide (SP; GPYLMVNVTGVDGKGNELL) previously enhanced the activation of plasminogen by the SAK/plasmin complex. OBJECTIVES: To identify the binding site for SP on plasminogen and elucidate the effects of SP on plasminogen activation by the tissue-type plasminogen activator (t-PA). METHODS: The effects of SP on plasminogen activation were estimated using a chromogenic substrate and from the cleavage of plasmin on SDS-PAGE under reduced conditions. The binding to SP of various peptides derived from the amino acid sequence of plasminogen was analyzed with an IAsys biosensor. The SP-mediated structural change to plasminogen was analyzed by circular dichroism (CD) spectroscopy. The thrombolytic effects of SP were examined using a mouse model of thrombosis. RESULTS: SP enhanced the activation of plasminogen by t-PA. The catalytic efficiency (k(cat)/K(m)) of Glu-plasminogen activation by t-PA was 11.4-fold higher in the presence than absence of SP. The binding of SP to plasminogen was greatly inhibited by a synthetic peptide, FEKDKYILQGVTSWGLG, located close to the C-terminal of the plasminogen B region. Near-ultraviolet CD spectra of the complex between SP and Glu-plasminogen significantly differed from those of Glu-plasminogen. When SP was administered in a mouse model of thrombosis, early recanalization was observed in a dose-dependent manner. However, SP did not cause recanalization in t-PA gene-deficient mice. CONCLUSIONS: SP bound to the B region and promoted the activation of plasminogen by t-PA, and then induced effective thrombolysis.

Okada K; Ueshima S; Matsuno H; Nagai N; Kawao N; Tanaka M; Matsuo O

2011-05-01

10

[Staphylokinase--a specific plasminogen activator].  

UK PubMed Central (United Kingdom)

Staphylokinase is a 135 amino acid protein produced by certain strains of Staphylococcus aureus. It belongs to fibrin-specific plasminogen activator. Staphylokinase converts plasminogen--the inactive proenzyme--to the plasmin, which dissolves the fibrin of a blood clots. This review will focus on the biochemical and thrombolytic properties of staphylokinase and its derivatives, which would make use of treatment in acute myocardial infarction and other cardiovascular diseases.

Rozpo?czyk E; Szemraj J; Malinowski M; Rozpo?czyk J

2006-01-01

11

[Staphylokinase--a specific plasminogen activator].  

Science.gov (United States)

Staphylokinase is a 135 amino acid protein produced by certain strains of Staphylococcus aureus. It belongs to fibrin-specific plasminogen activator. Staphylokinase converts plasminogen--the inactive proenzyme--to the plasmin, which dissolves the fibrin of a blood clots. This review will focus on the biochemical and thrombolytic properties of staphylokinase and its derivatives, which would make use of treatment in acute myocardial infarction and other cardiovascular diseases. PMID:16869305

Rozpo?czyk, Elibieta; Szemraj, Janusz; Malinowski, Mariusz; Rozpo?czyk, Jolanta

2006-01-01

12

Annexin II: a plasminogen-plasminogen activator co-receptor.  

Science.gov (United States)

Fibrinolysis is a precisely orchestrated process in which fibrin-containing thrombi are solubilized. Several receptors regulate this process by localizing proteolytic activity to the cell surface. One such receptor is annexin II, a calcium and phospholipid-binding protein. Annexin II serves as a profibrinolytic coreceptor for both plasminogen and tissue plasminogen activator on the surface of endothelial cells and facilitates the generation of plasmin. The dysregulation of fibrinolytic assembly on endothelial cells may lead to atherothrombotic disease. In addition to its role in fibrinolysis at the surface of endothelial cells, annexin II may play other potential cellular roles. For example, the overexpression of annexin II on the surface of leukemic cells and cell lines derived from acute promyelocytic leukemia correlates with both the clinical manifestation of bleeding and the in vitro ability of the leukemic cells to generate plasmin. The abundant presence of annexin II on the surface of other cell types including monocytic cell lines and different cancer cells may contribute to their invasive potential through extracellular matrix either by generation of plasmin or, by plasmin-mediated proteolytic activation of other metalloproteinases. This dissolution of extracellular matrix may also cause the release of potent matrix-bound angiogenic factors such as VEGF and FGF. On the other hand, by increasing the pool of plasmin, a precursor to an important anti-angiogenic factor, angiostatin, and by fragmentation of collagen XVIII (a precursor to the anti-angigenic factor, endostatin) by plasmin-activated metalloproteases, annexin II could play a pivotal physiological role in the pro- and anti-angiogenic switch mechanism. PMID:11815288

Kim, Jiyun; Hajjar, Katherine A

2002-02-01

13

Zinc Inhibits Tumor Metastasis by Regulating Plasminogen Activation  

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In this study, we found that zinc exerted a dual inhibition effect on plasminogen activator/plasmin system by inhibiting plasminogen activator activation and down-regulating plasmin activity. Zinc demonstrated significant inhibition effects on plasminogen activator and plasmin induced cell ...

Zhigang Tu; Jun F. Liang

14

SECRETION OF PLASMINOGEN ACTIVATOR BY STIMULATED MACROPHAGES  

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Cultured thioglycollate-stimulated peritoneal macrophages synthesize, accumulate, and continuously release high levels of plasminogen activators for at least 4 days whereas cultures of unstimulated macrophages do not; the higher specific catalytic activity of released vs. cell-associated enzyme sug...

Unkeless, Jay C.; Gordon, Saimon; Reich, E.

15

Tissue plasminogen activator and glaucoma drainage implants.  

UK PubMed Central (United Kingdom)

PURPOSE: The tube lumen of a glaucoma drainage implant is prone to occlusion by a blood or fibrin clot due to its small caliber, relatively low flow rate, and the plasmoid nature of the aqueous humor passing through it in the early postoperative period. The use of tissue plasminogen activator in the management of drainage tube obstruction is described herein. METHODS: Two cases of drainage tube obstruction in patients with neovascular glaucoma treated with an intracameral injection of tissue plasminogen activator are reported. RESULTS: Resolution of tube obstruction following tissue plasminogen activator administration with spontaneous lowering of the intraocular pressure and bleb formation was achieved in both cases. Differentiation of tube obstruction from other causes of elevated intraocular pressure following installation of glaucoma drainage devices is discussed. CONCLUSION: The intracameral injection of tissue plasminogen activator may relieve drainage tube obstruction secondary to a blood or fibrin clot, even in the absence of any visible clot covering the proximal tube ostium or within the anterior chamber portion of the tube. This approach should be considered, in selected cases, prior to more invasive surgical revision.

Sidoti PA; Morinelli EN; Heuer DK; Lundy DC; Lee PP; Minckler DS

1995-08-01

16

Intravitreal tissue plasminogen activator in submacular haemorrhage.  

UK PubMed Central (United Kingdom)

Submacular haemorrhage is a major cause of sudden visual loss in age-related macular degeneration (AMD). If left untreated it often results in permanent central visual loss. We present our experience in the use of intravitreal tissue plasminogen activator (tPA) in a 65-year-old male with submacular haemorrhage.

Singh P; Singh R; Kishore KS; Vig VK; Singh R; Singh B

1999-12-01

17

COMPOUND AND METHOD FOR REGULATING PLASMINOGEN ACTIVATION AND CELL MIGRATION  

UK PubMed Central (United Kingdom)

The invention relates to novel regulators of plasminogen activation and their use for regulating cell migration, plasminolysis, angiogenesis, fibrinolysis, for treating cancer and thrombo-embolic diseases such as heart stroke. Furthermore, the present invention relates to novel pharmaceutical compositions form regulating cell migration, plasminolysis, angiogenesis and for treating cancer. In particular, the present invention relates to a method of regulating the activation of plasminogen comprising contacting a solution of pro-urokinase (uPA) or tissue plasminogen activator (tPA) and plasminogen with melanotransferrin (p97) for a time sufficient to effect regulation thereof.

BELIVEAU RICHARD; DEMEULE MICHEL; BERTRAND YANICK; MICHAUD-LEVESQUE JONATHAN; ROLLAND YANNEVE; JODOIN JULIE

18

On a plasminogen activator from human plasma.  

UK PubMed Central (United Kingdom)

A plasminogen activating substance was purified from the dialysates of the eluates of glass adsorbed kallikrein from fresh human plasma, by chromatography on QAE-Sephadex A-50 and gel filtration in Sephadex G-25. The preparation was concentrated by lyophilization. Its electrophoretic mobility was found to be similar to that of prealbumin. Its molecular weight appeared to be 15000-18000 daltons. The analysis of aminoacids of this activator showed that it contains a high proportion of acid amino acids. The purified activator showed esterase activity, fibrinolytic activity and kininogenase activity on heated human plasma. These activities were respectively equivalent to 150 muM BAEe/mg protein, 19 x 10(3) units of streptokinase/microgram protein and 250 microgram bradykinin/mg protein.

Batista AD; Solana GH; Almonte JF

1980-02-01

19

Structural diversity of streptokinase and activation of human plasminogen.  

UK PubMed Central (United Kingdom)

The beta domain of streptokinase is required for plasminogen activation and contains a region of sequence diversity associated with infection and disease in group A streptococci. We report that mutagenesis of this polymorphic region does not alter plasminogen activation, which suggests an alternative function for this molecular motif in streptococcal disease.

Lizano S; Johnston KH

2005-07-01

20

Structural Diversity of Streptokinase and Activation of Human Plasminogen  

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The ? domain of streptokinase is required for plasminogen activation and contains a region of sequence diversity associated with infection and disease in group A streptococci. We report that mutagenesis of this polymorphic region does not alter plasminogen activation, which suggests an alternative f...

Lizano, Sergio; Johnston, Kenneth H.

 
 
 
 
21

Structural diversity of streptokinase and activation of human plasminogen.  

Science.gov (United States)

The beta domain of streptokinase is required for plasminogen activation and contains a region of sequence diversity associated with infection and disease in group A streptococci. We report that mutagenesis of this polymorphic region does not alter plasminogen activation, which suggests an alternative function for this molecular motif in streptococcal disease. PMID:15972548

Lizano, Sergio; Johnston, Kenneth H

2005-07-01

22

Structural consideration of the formation of the activation complex between the staphylokinase-like streptococcal plasminogen activator PadA and bovine plasminogen.  

Science.gov (United States)

The characteristics of a streptococcal plasminogen activator (PA) displaying specificity for ruminant plasminogen (Plg) were defined using molecular approaches. The 16-kDa secreted protein PadA was found to be prevalent in Streptococcus dysgalactiae subspecies dysgalactiae isolated from cases of bovine mastitis and septic arthritis in lambs. PadA was able to activate bovine, ovine and caprine Plg, but not human Plg. Amino acid sequence analysis identified a limited level of homology to other streptococcal PAs, including streptokinase; however, PadA was found to align well with and match in size the staphylococcal PA, staphylokinase. Recombinant PadA was used to investigate interaction with bovine Plg, leading to formation of an activator complex that was capable of recruiting and converting further substrate Plg into plasmin. Individual non-overlapping peptides of PadA or bovine microplasminogen were found to block the interaction between PadA and bovine Plg, preventing the formation of the activation complex. Homology modelling based upon structures of staphylokinase complexed with human microplasminogen supported these findings by placing critical residues in close proximity to the plasmin component of the activation complex. PMID:18588895

Ward, Philip N; Abu-Median, Abu-Bakr A K; Leigh, James A

2008-06-17

23

Activation of immobilized plasminogen by tissue activator. Multimolecular complex formation  

Energy Technology Data Exchange (ETDEWEB)

Ternary complex formation of tissue plasminogen activator (TPA) and plasminogen (Plg) with thrombospondin (TSP) or histidine-rich glycoprotein (HRGP) has been demonstrated using an enzyme-linked immunosorbent assay, an affinity bead assay, and a rocket immunoelectrophoresis assay. The formation of these complexes was specific, concentration dependent, saturable, lysine binding site-dependent, and inhibitable by fluid phase plasminogen. Apparent Kd values were approximately 12-36 nM for the interaction of TPA with TSP-Plg complexes and 15-31 nM with HRGP-Plg complexes. At saturation the relative molar stoichiometry of Plg:TPA was 3:1 within the TSP-containing complexes and 1:1 within HRGP-containing complexes. The activation of Plg to plasmin by TPA on TSP- and HRGP-coated surfaces was studied using a synthetic fluorometric plasmin substrate (D-Val-Leu-Lys-7-amino-4-trifluoromethyl coumarin). Kinetic analysis demonstrated a marked increase in the affinity of TPA for plasminogen in the presence of surface-associated TSP or HRGP. Complex formation of locally released tissue plasminogen activator with Plg immobilized on TSP or HRGP surfaces may thus play an important role in effecting proteolytic events in nonfibrin-containing microenvironments.

Silverstein, R.L.; Nachman, R.L.; Leung, L.L.; Harpel, P.C.

1985-08-25

24

Activation of immobilized plasminogen by tissue activator. Multimolecular complex formation  

International Nuclear Information System (INIS)

[en] Ternary complex formation of tissue plasminogen activator (TPA) and plasminogen (Plg) with thrombospondin (TSP) or histidine-rich glycoprotein (HRGP) has been demonstrated using an enzyme-linked immunosorbent assay, an affinity bead assay, and a rocket immunoelectrophoresis assay. The formation of these complexes was specific, concentration dependent, saturable, lysine binding site-dependent, and inhibitable by fluid phase plasminogen. Apparent Kd values were approximately 12-36 nM for the interaction of TPA with TSP-Plg complexes and 15-31 nM with HRGP-Plg complexes. At saturation the relative molar stoichiometry of Plg:TPA was 3:1 within the TSP-containing complexes and 1:1 within HRGP-containing complexes. The activation of Plg to plasmin by TPA on TSP- and HRGP-coated surfaces was studied using a synthetic fluorometric plasmin substrate (D-Val-Leu-Lys-7-amino-4-trifluoromethyl coumarin). Kinetic analysis demonstrated a marked increase in the affinity of TPA for plasminogen in the presence of surface-associated TSP or HRGP. Complex formation of locally released tissue plasminogen activator with Plg immobilized on TSP or HRGP surfaces may thus play an important role in effecting proteolytic events in nonfibrin-containing microenvironments

1985-08-25

25

Acoustic determination of performance and equivalence of plasminogen activators.  

Science.gov (United States)

A reliable method for the measurement of different plasminogen activators is of great interest for both manufacturing and clinical medicine. A one-step assay based on a thickness shear mode acoustic sensor has been developed for this purpose. Two separate mixtures of substrates (fibrinogen and plasminogen) and enzymes (thrombin and the plasminogen activator) were mixed, and placed on the acoustic sensor surface. During the assay, the resonant frequency of a quartz crystal oscillating in the thickness shear mode was measured and used to find a characteristic clot dissolution time, from the sample addition to the time at the maximum dissolution rate. Calibrations of the acoustic assay were done for tissue-type plasminogen activator (t-PA) as well as for the other plasminogen activators: urokinase (u-PA); streptokinase (SK) and staphylokinase (SAK). All gave relative standard deviations of about 12%. Since the same method was used for all of the activators, their activities were compared, resolving the differences between their unit definitions. Linear relationships were found between urokinase and streptokinase which activate plasminogen directly and between t-PA and staphylokinase which require fibrin as a cofactor. The relationship between the groups was found to curve, indicating the difference between the two mechanisms. The acoustic method, therefore, may be used as a rapid and cost-effective reference method for the standardization and comparison of different plasminogen activators. PMID:18759103

Ghazali, Mirnader; Hayward, Gordon L

2008-08-31

26

Immunological characterization of plasminogen activators in human parotid saliva.  

UK PubMed Central (United Kingdom)

These were characterized in stimulated saliva from 21 healthy volunteers using antibodies specific for human tissue-type plasminogen activator (t-PA) or urokinase. After pre-incubation with immunoglobulins, with and without specific antibodies, the fibrinolytic activity was assayed on fibrin plates containing plasminogen. Fibrinolytic activity was demonstrated in all salivas but one; it was completely quenched by antibodies against t-PA, but antibodies against urokinase-like plasminogen activator had no effect. The fibrinolytic activity was expressed in international units (IU) using a standard curve obtained by serial dilution of the international tissue-plasminogen standard. The normal range was 0.05-0.35 IU/ml, and the maximal value 2 IU/ml. There is thus considerable individual variation in fibrinolytic activity in parotid saliva, where it is regulated by t-PA under physiological conditions.

Kjaeldgaard M; Kjaeldgaard A

1987-01-01

27

Inactivation of plasminogen activator inhibitor by oxidants  

Energy Technology Data Exchange (ETDEWEB)

The rapidly acting plasminogen activator inhibitor (PAI) purified from cultured bovine endothelial cells (BAEs) was inactivated during iodination with chloramine T and other oxidizing iodination systems. Inactivation was observed in the absence of iodine, suggesting that the loss of activity resulted from the oxidizing conditions employed. In an attempt to further study the nature of this inactivation, the PAI was treated with chloramine T under conditions that specifically oxidize methionine and cystein residues. Both PAI inhibitory activity and the ability of the PAI to form complexes with tissue-type PA were decreased in a dose-dependent manner by such treatment. PAI activity was measured with the lysis of /sup 125/I-labelled fibrin. The reductase is a DTT-dependent enzyme that specifically converts methionine sulfoxide to methionine. Little activity was restored by either the reductase or DTT alone. These results indicate that the oxidation of at least one critical methionine residue is responsible for the loss of PAI activity upon iodination. In this respect, the BAE PAI resembles ..cap alpha../sub 1/-protease inhibitor, a well-characterized elastase inhibitor that also is inactivated by oxidants. Both inhibitors are members of the serine protease inhibitor superfamily (Serpins), and both have a methionine residue in their reactive center.

Lawrence, D.A.; Loskutoff, D.J.

1986-10-21

28

Inactivation of plasminogen activator inhibitor by oxidants  

International Nuclear Information System (INIS)

[en] The rapidly acting plasminogen activator inhibitor (PAI) purified from cultured bovine endothelial cells (BAEs) was inactivated during iodination with chloramine T and other oxidizing iodination systems. Inactivation was observed in the absence of iodine, suggesting that the loss of activity resulted from the oxidizing conditions employed. In an attempt to further study the nature of this inactivation, the PAI was treated with chloramine T under conditions that specifically oxidize methionine and cystein residues. Both PAI inhibitory activity and the ability of the PAI to form complexes with tissue-type PA were decreased in a dose-dependent manner by such treatment. PAI activity was measured with the lysis of 125I-labelled fibrin. The reductase is a DTT-dependent enzyme that specifically converts methionine sulfoxide to methionine. Little activity was restored by either the reductase or DTT alone. These results indicate that the oxidation of at least one critical methionine residue is responsible for the loss of PAI activity upon iodination. In this respect, the BAE PAI resembles ?1-protease inhibitor, a well-characterized elastase inhibitor that also is inactivated by oxidants. Both inhibitors are members of the serine protease inhibitor superfamily (Serpins), and both have a methionine residue in their reactive center

1986-10-21

29

Matrix plasminogen activator inhibitor. Modulation of the extracellular proteolytic environment.  

UK PubMed Central (United Kingdom)

We have previously demonstrated that plasminogen activator inhibitor (PAI-1) is associated with the extracellular matrix of cultured bovine smooth muscle cells (Knudsen, B.S., Harpel, P.C., Nachman, R.L. (1987) J. Clin. Invest. 80, 1082-1089). In this report we describe the physiologic role of PAI-1 during the interaction of the tissue plasminogen activator (t-PA) secreting Bowes human melanoma cell line with endothelial extracellular matrices. In addition we have characterized the t-PA.PAI complexes formed during this interaction in the presence and absence of plasminogen. In the absence of plasminogen, a 104-kDa complex between Bowes t-PA and PAI-1 appears in the supernatant. In the presence of plasminogen, PAI initially prevents plasmin formation on the matrix and protects the matrix from degradation by plasmin. The 104-kDa t-PA.PAI complex is degraded into a 68 and a 47-kDa complex by small amounts of plasmin generated from secreted Bowes t-PA and plasminogen. Analysis of these complexes revealed that t-PA is rapidly cleaved by plasmin within the complex whereas complexed PAI-1 is not further degraded. Matrix-associated PAI-1 may play an important role in the protection of extracellular matrices from remodeling and degradation by cellular t-PA and plasminogen.

Knudsen BS; Nachman RL

1988-07-01

30

Increased alveolar plasminogen activator in early asbestosis  

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Alveolar macrophage-derived plasminogen activator (PA) activity is decreased in some chronic interstitial lung diseases such as idiopathic pulmonary fibrosis and sarcoidosis but increased in experimental models of acute alveolitis. Although asbestos fibers can stimulate alveolar macrophages (AM) to release PA in vitro, the effect of chronic asbestos exposure of the lower respiratory tract on lung PA activity remains unknown. The present study was designed to evaluate PA activity of alveolar macrophages and bronchoalveolar lavage (BAL) fluid in asbestos-exposed sheep and asbestos workers. Forty-three sheep were exposed to either 100 mg UICC chrysotile B asbestos in 100 ml phosphate-buffered saline (PBS) or to 100 ml PBS by tracheal infusion every 2 wk for 18 months. At Month 18, chest roentgenograms were analyzed and alveolar macrophage and extracellular fluid PA activity were measured in samples obtained by BAL. Alveolar macrophage PA activity was increased in the asbestos-exposed sheep compared to control sheep (87.2 +/- 17.3 versus 41.1 +/- 7.2 U/10(5) AM-24 h, p less than 0.05) as was the BAL fluid PA activity (674.9 +/- 168.4 versus 81.3 +/- 19.7 U/mg alb-24 h, p less than 0.01). Among the asbestos-exposed sheep, 10 had normal chest roentgenograms (Group SA) and 15 had irregular interstitial opacities (Group SB). Strikingly, whereas Group SA did not differ from the control group in BAL cellularity or PA activity, Group SB had marked increases in alveolar macrophages (p less than 0.005), AM PA activity (p less than 0.02), and BAL PA activity (p less than 0.001) compared to the control group.

Cantin, A.; Allard, C.; Begin, R.

1989-03-01

31

Tissue Plasminogen Activator (tPA) Mediates Neurotoxin-Induced Cell Death and Microglial Activation.  

Science.gov (United States)

Neuronal death occurs in the brain during development and in pathological conditions, like Alzheimer's disease and stroke. Tissue plasminogen activator (tPA), a protease converting plasminogen to plasmin, is necessary for neurodegeneration. In mice lackin...

S. E. Tsirka

2001-01-01

32

Assembly of urokinase receptor-mediated plasminogen activation complexes involves direct, non-active-site interactions between urokinase and plasminogen.  

UK PubMed Central (United Kingdom)

The binding of the zymogenic form of urokinase-type plasminogen activator (pro-uPA) to its specific cellular receptor, uPAR, leads to a large potentiation of plasmin generation. This is dependent on the concurrent cellular binding of plasminogen, and is completely abrogated by the plasminogen lysine-binding site ligand, 6-aminohexanoic acid. Previous data have provided circumstantial evidence for the formation of specific complexes to mediate the kinetically favorable reciprocal interactions between the protease and zymogen components [Ellis, V., and Dano, K. (1993) J. Biol. Chem. 268, 4806-4813]. To further investigate the formation of these putative complexes, we have studied the effect of various lysine-binding site ligands on the binding and activation of plasminogen on U937 cells. Lysine-binding site ligands resembling internal lysine residues, such as Nalpha-acetyl-L-lysine methyl ester, were found to specifically inhibit uPAR-mediated cell-surface plasminogen activation at concentrations up to 40-fold lower than those inhibiting the cellular binding of 125I-labeled plasminogen (IC50s 300 microM vs 8.5 mM). By contrast, 6-aminohexanoic acid, resembling a C-terminal lysine residue, did not display this disparity (IC50s 25 vs 30 microM). These lysine analogues were also found to compete a non-active-site interaction between uPA and plasminogen, detected by surface plasmon resonance (Kd 50 nM), at concentrations correlating with their effect on cell-surface plasminogen activation, suggesting that this interaction is part of the kinetic mechanism. Consistent with this, synthetic peptides corresponding to the sequence uPA149-158 (GQKTLRPRFK) and uPA149-157 (GQKTLRPRF) specifically abolished the amplification of cell-surface plasminogen activation. These data demonstrate that a novel non-active-site interaction between uPA and plasminogen is necessary for the assembly and efficiency of cell-surface plasminogen activation complexes.

Ellis V; Whawell SA; Werner F; Deadman JJ

1999-01-01

33

Macrophages associated with murine tumours express plasminogen activator activity.  

UK PubMed Central (United Kingdom)

The fibrinolytic activity of cancer cells has been repeatedly implicated in mechanisms of local spread and tumour invasiveness. Mononuclear phagocytes associated with solid tumours might also contribute to fibrin dissolution at the tumour/host interface through the expression of plasminogen activator (PA) activity. We have investigated the PA activity of tumour-associated macrophages (TAM) from 4 transplanted murine tumours in syngeneic hosts; peritoneal macrophages (native and thioglycolate-elicited) from both tumour-bearing and control animals were studied as reference cells. TAM from 3 tumours (MSV, mFS6, MN/MCAI) had basal levels of PA activity (20% plasminogen-independent) comparable to or higher than those of thioglycolate-elicited peritoneal macrophages from the same tumour-bearing animals. TAM isolated from 1 tumour (MS2) had a PA which was very low (60% plasminogen-independent), but higher than the activity of unstimulated peritoneal macrophages. Molecular analysis of PA by SDS-PAGE electrophoresis and fibrin autography revealed in all macrophages a single species having an apparent MW of 48 kDA. It thus appears that, in some experimental neoplasms, tumour cell vicinity may represent an in vivo stimulus for macrophage PA expression.

Mussoni L; Riganti M; Acero R; Erroi A; Conforti G; Mantovani A; Donati MB

1988-02-01

34

Circadian fluctuations of tissue plasminogen activator antigen and plasminogen activator inhibitor-1 antigens in vasospastic angina.  

UK PubMed Central (United Kingdom)

To elucidate the circadian variation of fibrinolytic components in vasospastic angina, plasma levels of tissue plasminogen activator antigen (t-PA), free plasminogen activator inhibitor antigen (free PAI-1), t-PA/PAI-1 complex, and total PAI-1 were measured in venous plasma samples. Samples were taken every 6 hours (6:00 AM, noon, 6:00 PM, and midnight) for 24 hours in 14 patients with vasospastic angina, in 9 patients with exertional angina, and in 19 normal subjects. Twenty-four-hour Holter monitoring (Holter monitor, Del Mar Avionics, Irvine, Calif.) was also carried out in all subjects. All of the fibrinolytic components showed circadian variation, with a peak level at 6:00 AM in every study group except for the t-PA/PAI-1 complex in the group of patients with exertional angina. The values for all or the fibrinolytic components at each sampling time were higher in patients with coronary artery disease than in normal subjects. In particular, the mean value of free PAI-1 at 6:00 AM in patients with vasospastic angina was significantly higher than that in normal subjects and that in patients with exertional angina. This value of free PAI-1 in patients with vasospastic angina was closely associated with the duration of ischemic attacks. These results suggested that the circadian fluctuation of fibrinolytic components may be an important factor that leads to coronary thrombosis at the time of coronary spasm, especially in the early morning.

Sakata K; Hoshino T; Yoshida H; Ono N; Ohtani S; Yokoyama S; Mori N; Kaburagi T; Kurata C; Urano T

1992-10-01

35

Activators and inhibitors of the plasminogen system in Alzheimer's disease.  

UK PubMed Central (United Kingdom)

Accumulation and deposition of A? is one of the main neuropathological hallmarks of Alzheimer's disease (AD) and impaired A? degradation may be one mechanism of accumulation. Plasmin is the key protease of the plasminogen system and can cleave A?. Plasmin is activated from plasminogen by tissue plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). The activators are regulated by inhibitors which include plasminogen activator inhibitor-1 (PAI-1) and neuroserpin. Plasmin is also regulated by inhibitors including ?2-antiplasmin and ?2-macroglobulin. Here, we investigate the mRNA levels of the activators and inhibitors of the plasminogen system and the protein levels of tPA, neuroserpin and ?2-antiplasmin in post-mortem AD and control brain tissue. Distribution of the activators and inhibitors in human brain sections was assessed by immunoperoxidase staining. mRNA measurements were made in 20 AD and 20 control brains by real-time PCR. In an expanded cohort of 38 AD and 38 control brains tPA, neuroserpin and ?2-antiplasmin protein levels were measured by ELISA. The activators and inhibitors were present mainly in neurons and ?2-antiplasmin was also associated with A? plaques in AD brain tissue. tPA, uPA, PAI-1 and ?2-antiplasmin mRNA were all significantly increased in AD compared to controls, as were tPA and ?2-antiplasmin protein, whereas neuroserpin mRNA and protein were significantly reduced. ?2-macroglobulin mRNA was not significantly altered in AD. The increases in tPA, uPA, PAI-1 and ?2-antiplasmin may counteract each other so that plasmin activity is not significantly altered in AD, but increased tPA may also affect synaptic plasticity, excitotoxic neuronal death and apoptosis.

Barker R; Kehoe PG; Love S

2012-04-01

36

Structural basis for recognition of urokinase-type plasminogen activator by plasminogen activator inhibitor-1  

DEFF Research Database (Denmark)

Plasminogen activator inhibitor-1 (PAI-1), together with its physiological target urokinase-type plasminogen activator (uPA), plays a pivotal role in fibrinolysis, cell migration, and tissue remodeling and is currently recognized as being among the most extensively validated biological prognostic factors in several cancer types. PAI-1 specifically and rapidly inhibits uPA and tissue-type PA (tPA). Despite extensive structural/functional studies on these two reactions, the underlying structural mechanism has remained unknown due to the technical difficulties of obtaining the relevant structures. Here, we report a strategy to generate a PAI-1·uPA(S195A) Michaelis complex and present its crystal structure at 2.3-Å resolution. In this structure, the PAI-1 reactive center loop serves as a bait to attract uPA onto the top of the PAI-1 molecule. The P4-P3' residues of the reactive center loop interact extensively with the uPA catalytic site, accounting for about two-thirds of the total contact area. Besides the active site, almost all uPA exosite loops, including the 37-, 60-, 97-, 147-, and 217-loops, are involved in the interaction with PAI-1. The uPA 37-loop makes an extensive interaction with PAI-1 ?-sheet B, and the 147-loop directly contacts PAI-1 ?-sheet C. Both loops are important for initial Michaelis complex formation. This study lays down a foundation for understanding the specificity of PAI-1 for uPA and tPA and provides a structural basis for further functional studies.

Lin, Zhonghui; Jiang, Longguang

2011-01-01

37

Staphylokinase as a Plasminogen Activator Component in Recombinant Fusion Proteins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The plasminogen activator staphylokinase (SAK) is a promising thrombolytic agent for treatment of myocardial infarction. It can specifically stimulate the thrombolysis of both erythrocyte-rich and platelet-rich clots. However, SAK lacks fibrin-binding and thrombin inhibitor activities, two functions...

Szarka, S. J.; Sihota, E. G.; Habibi, H. R.; Wong, S.-L.

38

Plasminogen activator inhibitor-1 inhibitors: a patent review (2006-present).  

UK PubMed Central (United Kingdom)

INTRODUCTION: Plasminogen activator inhibitor-1 (PAI-1), the serine protease inhibitor (serpin), binds to and inhibits the plasminogen activators-tissue-type plasminogen activator (tPA) and the urokinase-type plasminogen activator (uPA). This results in both a decrease in plasmin production and a decrease in the dissolution of fibrin clots. Elevated levels of PAI-1 are correlated with an increased risk for cardiovascular disease and have been linked to obesity and metabolic syndrome. Consequently, the pharmacological suppression of PAI-1 might prevent or treat vascular disease. AREAS COVERED: This article provides an overview of the patenting activity on PAI-1 inhibitors. Patents filed by pharmaceutical companies or individual research groups are described, and the biological and biochemical evaluation of the inhibitors, including in vitro and in vivo studies, is discussed. An overview of patents pertaining to using these inhibitors for treating various diseases is also included. EXPERT OPINION: Although there is still no PAI-1 inhibitor being evaluated in a clinical setting or approved for human therapy, research in this field has progressed, and promising new compounds have been designed. Most research has focused on improving the pharmacological profile of these compounds, which will hopefully allow them to proceed to clinical studies. Despite the need for further testing and research, the potential use of PAI-1 inhibitors for treating cardiovascular disease appears quite promising.

Fortenberry YM

2013-07-01

39

Structural features mediating fibrin selectivity of vampire bat plasminogen activators.  

Science.gov (United States)

The distinguishing characteristic of vampire bat (Desmodus rotundus) salivary plasminogen activators (DSPAs) is their strict requirement for fibrin as a cofactor. DSPAs consist of structural modules known from urokinase (u-PA) and tissue-type plasminogen activator (t-PA) such as finger (F), epidermal growth factor (E), kringle (K), and protease (P), combining to four genetically and biochemically distinct isoenzymes, exhibiting the formulas FEKP (DSPA alpha 1 and alpha 2) and EKP and KP (DSPA beta and DSPA gamma). Only DSPA alpha 1 and alpha 2 bind to fibrin. All DSPAs are single-chain molecules, displaying substantial amidolytic activity. In a plasminogen activation assay, all four DSPAs are almost inactive in the absence of fibrin but strongly stimulated by fibrin addition. The catalytic efficiency (kcat/Km) of DSPA alpha 1 increases 10(5)-fold, whereas the corresponding value of t-PA is only 550. The ratio of the bimolecular rate constants of plasminogen activation in the presence of fibrin versus fibrinogen (fibrin selectivity) of DSPA alpha 1, alpha 2, beta, gamma, and t-PA was found to be 13,000, 6500, 250, 90, and 72, respectively. Whereas all DSPAs are therefore more fibrin dependent and fibrin selective than t-PA, the extent depends on the respective presence of the various domains. The introduction of a plasmin-sensitive cleavage site in a position akin to the one in t-PA partially obliterates fibrin cofactor requirement. Fibrin dependence and fibrin selectivity of DSPAs are accordingly mediated by fibrin binding, which involves the F domain, as yet undefined determinants within the K and P domains, and by the absence of a plasmin-sensitive activation site. These findings transcend the current understanding of fibrin-mediated stimulation of plasminogen activation: in addition to fibrin binding, specific protein-protein interactions come into play, which stabilize the enzyme in its active conformation. PMID:7592732

Bringmann, P; Gruber, D; Liese, A; Toschi, L; Krätzchmar, J; Schleuning, W D; Donner, P

1995-10-27

40

Plasminogen Activator Inhibitor-1 Antisense Oligodeoxynucleotides Abrogate Mesangial Fibronectin Accumulation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Excessive extracellular matrix (ECM) accumulation is the main feature of chronic renal disease including diabetic nephropathy. Plasminogen activator inhibitor (PAI)-1 is known to play an important role in renal ECM accumulation in part through suppression of plasmin generation and matrix metalloprot...

Park, Jehyun; Seo, Ji Yeon; Ha, Hunjoo

 
 
 
 
41

Secretion of platelet-activating factor by periovulatory ovine follicles  

International Nuclear Information System (INIS)

Secretion of platelet-activating factor (PAF) in vitro by ovine follicles and ovarian interstitium obtained at various times before, during and after the endogenous preovulatory surge of luteinizing hormone (LH) and ovulation was quantified by radioimmunoassay. Release of PAF by the preovulatory follicle increased within 2 h after initiation of the surge of LH. Capacity for secretion of PAF was greatest at the time of ovulation, then declined thereafter. Production of PAF by ovarian interstitium throughout the periovulatory period was relatively low and did not change with time. It appears that PAF could act as an intrafollicular mediator in the mechanisms of ovulation and(or) luteinization

1990-01-01

42

Secretion of platelet-activating factor by periovulatory ovine follicles  

Energy Technology Data Exchange (ETDEWEB)

Secretion of platelet-activating factor (PAF) in vitro by ovine follicles and ovarian interstitium obtained at various times before, during and after the endogenous preovulatory surge of luteinizing hormone (LH) and ovulation was quantified by radioimmunoassay. Release of PAF by the preovulatory follicle increased within 2 h after initiation of the surge of LH. Capacity for secretion of PAF was greatest at the time of ovulation, then declined thereafter. Production of PAF by ovarian interstitium throughout the periovulatory period was relatively low and did not change with time. It appears that PAF could act as an intrafollicular mediator in the mechanisms of ovulation and(or) luteinization.

Alexander, B.M.; Van Kirk, E.A.; Murdoch, W.J. (Univ. of Wyoming, Laramie (USA))

1990-01-01

43

Comparative molecular analysis of ovine and bovine Streptococcus uberis isolates.  

UK PubMed Central (United Kingdom)

Streptococcus uberis causes clinical and subclinical mastitis in cattle and sheep, but it is unknown whether the composition of Strep. uberis populations differs between host species. To address this, we characterized a collection of bovine and ovine Strep. uberis isolates with shared geographical and temporal origins by means of an expanded multilocus sequence typing scheme. Among 14 ovine and 35 bovine isolates, 35 allelic profiles were detected. Each allelic profile was associated with a single host species and all but one were new to the multilocus sequence typing database. The median number of new alleles per isolate was higher for ovine isolates than for bovine isolates. None of the ovine isolates belonged to the global clonal complexes 5 or 143, which are commonly associated with bovine mastitis and which have a wide geographical distribution. Ovine isolates also differed from bovine isolates in carriage of plasminogen activator genes, with significantly higher prevalence of pauB in ovine isolates. Isolates that were negative for yqiL, one of the targets of multilocus sequence typing, were found among ovine and bovine isolates and were not associated with a specific sequence type or global clonal complex. One bovine isolate carried a gapC allele that was probably acquired through lateral gene transfer, most likely from Streptococcus salivarius. We conclude that ovine isolates are distinct from bovine isolates of Strep. uberis, and that recombination between isolates from different host species or bacterial species could contribute to changes in virulence gene profiles with relevance for vaccine development.

Gilchrist TL; Smith DG; Fitzpatrick JL; Zadoks RN; Fontaine MC

2013-02-01

44

Comparative molecular analysis of ovine and bovine Streptococcus uberis isolates.  

Science.gov (United States)

Streptococcus uberis causes clinical and subclinical mastitis in cattle and sheep, but it is unknown whether the composition of Strep. uberis populations differs between host species. To address this, we characterized a collection of bovine and ovine Strep. uberis isolates with shared geographical and temporal origins by means of an expanded multilocus sequence typing scheme. Among 14 ovine and 35 bovine isolates, 35 allelic profiles were detected. Each allelic profile was associated with a single host species and all but one were new to the multilocus sequence typing database. The median number of new alleles per isolate was higher for ovine isolates than for bovine isolates. None of the ovine isolates belonged to the global clonal complexes 5 or 143, which are commonly associated with bovine mastitis and which have a wide geographical distribution. Ovine isolates also differed from bovine isolates in carriage of plasminogen activator genes, with significantly higher prevalence of pauB in ovine isolates. Isolates that were negative for yqiL, one of the targets of multilocus sequence typing, were found among ovine and bovine isolates and were not associated with a specific sequence type or global clonal complex. One bovine isolate carried a gapC allele that was probably acquired through lateral gene transfer, most likely from Streptococcus salivarius. We conclude that ovine isolates are distinct from bovine isolates of Strep. uberis, and that recombination between isolates from different host species or bacterial species could contribute to changes in virulence gene profiles with relevance for vaccine development. PMID:23200465

Gilchrist, T L; Smith, D G E; Fitzpatrick, J L; Zadoks, R N; Fontaine, M C

2012-11-29

45

Clot penetration and retention by plasminogen activators promote fibrinolysis.  

UK PubMed Central (United Kingdom)

Tissue-type plasminogen activator (tPA) remains the sole thrombolytic approved by the FDA for the treatment of pulmonary embolism (PE). tPA has not been replaced by third generation plasminogen activators, e.g. Reteplase (Ret) and Tenecteplase (TNK) that circulate with longer life-spans and in theory should have more extended potency in vivo. One reason for this paradox is the inability to assign units of activity to plasminogen activators based on specific biologically relevant standards, which impairs objective comparison. Here, we compare clot permeation, retention and fibrinolytic activities of tPA, TNK and Ret in vitro and clot composition over time with outcome in a mouse model of disseminated pulmonary microembolism (ME). When clots were incubated in the continuous presence of drug, tPA, TNK and Ret lysed fibrin clots identically in the absence of PA inhibitor-1 (e.g. PAI-1). Ret, which has lower fibrin affinity and greater susceptibility to inhibition by PAI-1 than tPA, was less effective in lysing plasma clots, while TNK was less effective when the fibrin content of the clots was enhanced. However, when clots were afforded only brief exposure to drug, as occurs in vivo, Ret showed more extensive clot permeation, greater retention and lysis than tPA or TNK. These results were reproduced in vivo in a mouse model of ME. These studies indicate the need for more relevant tests of plasminogen activator activity in vitro and in vivo and they show that clot permeation and retention are important potential predictors of clinical utility.

Marcos-Contreras OA; Ganguly K; Yamamoto A; Shlansky-Goldberg R; Cines DB; Muzykantov VR; Murciano JC

2013-01-01

46

Antibodies to plasminogen activator inhibit human tumor metastasis.  

UK PubMed Central (United Kingdom)

The human carcinoma HEp3 grows on the chorioallantoic membrane and metastasizes to the chicken embryo with kinetics that are quantitatively predictable. We have used this experimental system to test whether plasminogen activator produced by the tumor is required for metastasis. Rabbit antibodies were raised against human urinary urokinase; these cross-reacted with and blocked the catalytic activity of HEp3-PA but did not inhibit chicken PA. When administered intravenously to embryos that had received an inoculum of HEp3 cells, the anti-urokinase antibodies did not inhibit tumor growth at the site of primary inoculation on the chorioallantoic membrane, but they either prevented or strongly inhibited metastasis to the embryo lung. Antibody treatment delayed the onset of pulmonary metastasis, indicating that plasminogen activator is required during early stages of the process.

Ossowski L; Reich E

1983-12-01

47

Antibodies to plasminogen activator inhibit human tumor metastasis.  

Science.gov (United States)

The human carcinoma HEp3 grows on the chorioallantoic membrane and metastasizes to the chicken embryo with kinetics that are quantitatively predictable. We have used this experimental system to test whether plasminogen activator produced by the tumor is required for metastasis. Rabbit antibodies were raised against human urinary urokinase; these cross-reacted with and blocked the catalytic activity of HEp3-PA but did not inhibit chicken PA. When administered intravenously to embryos that had received an inoculum of HEp3 cells, the anti-urokinase antibodies did not inhibit tumor growth at the site of primary inoculation on the chorioallantoic membrane, but they either prevented or strongly inhibited metastasis to the embryo lung. Antibody treatment delayed the onset of pulmonary metastasis, indicating that plasminogen activator is required during early stages of the process. PMID:6418388

Ossowski, L; Reich, E

1983-12-01

48

Thrombin-specific inactivation of endothelial cell derived plasminogen activator  

Energy Technology Data Exchange (ETDEWEB)

Although thrombin (T) has diverse functions in the overall hemostatic mechanism, relatively little is known about its direct effect on components of the fibrinolytic enzyme system. The authors have investigated the interaction of T with plasminogen activators (PA) derived from bovine aortic endothelial cells (EC) in culture (2-5th passage, preconfluent monolayers). Varying concentrations of purified bovine or human thrombin were added to EC-conditioned media (CM). CM + T mixtures were assayed at various times for PA activity using purified plasminogen and a sensitive /sup 125/I-fibrinogenolytic or caseinolytic assay. T (5 nM), but not plasmin or trypsin at equivalent concentrations, resulted in a time-dependent inhibition of the PA activity in CM. T had no effect on the PA activity of urokinase, streptokinase or preformed plasmin. The ability of T to inactivate the EC-derived PA was abolished by prior treatment of T with active site-directed reagents. SDS-PAGE and zymography with copolymerized fibrinogen and plasminogen revealed further specificity in that only one of the multiple-molecular weight forms of PA present in EC-CM was inactivated by T. The authors conclude that in a highly specific fashion, T inactivates the predominant PA present in EC-CM by limited proteolysis. Thus, another potentially important function of T is suggested which may have particular significance in the temporal regulation of coagulation and fibrinolysis at the blood-endothelium interface.

Highsmith, R.F.; Gallaher, M.J.

1986-03-05

49

Thrombin-specific inactivation of endothelial cell derived plasminogen activator  

International Nuclear Information System (INIS)

Although thrombin (T) has diverse functions in the overall hemostatic mechanism, relatively little is known about its direct effect on components of the fibrinolytic enzyme system. The authors have investigated the interaction of T with plasminogen activators (PA) derived from bovine aortic endothelial cells (EC) in culture (2-5th passage, preconfluent monolayers). Varying concentrations of purified bovine or human thrombin were added to EC-conditioned media (CM). CM + T mixtures were assayed at various times for PA activity using purified plasminogen and a sensitive 125I-fibrinogenolytic or caseinolytic assay. T (5 nM), but not plasmin or trypsin at equivalent concentrations, resulted in a time-dependent inhibition of the PA activity in CM. T had no effect on the PA activity of urokinase, streptokinase or preformed plasmin. The ability of T to inactivate the EC-derived PA was abolished by prior treatment of T with active site-directed reagents. SDS-PAGE and zymography with copolymerized fibrinogen and plasminogen revealed further specificity in that only one of the multiple-molecular weight forms of PA present in EC-CM was inactivated by T. The authors conclude that in a highly specific fashion, T inactivates the predominant PA present in EC-CM by limited proteolysis. Thus, another potentially important function of T is suggested which may have particular significance in the temporal regulation of coagulation and fibrinolysis at the blood-endothelium interface.

1986-01-01

50

Persistent plasminogen activator inhibitor 1 gene expression in cardiac transplant recipients with idiopathic dilated cardiomyopathy.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Plasminogen activator inhibitor 1 is the primary regulator of urokinase plasminogen activator and tissue plasminogen activator. Plasminogen activator inhibitor 1 is essential in the control of the thrombotic/fibrinolytic balance and is a marker of endothelial cell injury. Idiopathic dilated cardiomyopathy is reportedly associated with endothelial cell dysfunction. Whether endothelial cell damage plays a role in patients with dilated cardiomyopathy after cardiac transplantation remains unknown. METHODS: In this study explanted hearts of cardiac transplant recipients with ischemic cardiomyopathy and dilated cardiomyopathy, as well as control myocardial tissue, were investigated for expression of urokinase plasminogen activator, tissue plasminogen activator, urokinase plasminogen activator receptor, and plasminogen activator inhibitor 1 and 2. Furthermore, plasminogen activator inhibitor 1 expression was examined in endomyocardial biopsy specimens and sera of patients with ischemic cardiomyopathy and those with dilated cardiomyopathy during the first posttransplantation year. The effect of the patient's serum on endothelial cells was assessed in vitro to examine the role of circulating endothelial cell damage-related factors. RESULTS: Plasminogen activator inhibitor 1 expression was upregulated in ischemic cardiomyopathy and dilated cardiomyopathy myocardial tissue versus that seen in control tissue. After transplantation, plasminogen activator inhibitor 1 expression returned to control levels in patients with ischemic cardiomyopathy. In patients with dilated cardiomyopathy, plasminogen activator inhibitor 1 expression increased at 24 weeks after transplantation in both biopsy specimens and sera versus that seen in control tissue. Sera of patients with dilated cardiomyopathy, but not that of patients with ischemic cardiomyopathy, inhibited vascular endothelial growth factor A-induced proliferation of endothelial cells, although downstream target gene activation of early growth response factor 1 and NGFI-A binding protein 2 was not affected. CONCLUSIONS: These data suggest for the first time that the endothelial cell damage-related process recurs in patients with dilated cardiomyopathy after transplantation, which, independently of vascular endothelial growth factor, is associated with increased plasminogen activator inhibitor 1 expression, and that this pathology might play a role in allograft remodeling in patients with dilated cardiomyopathy.

Schäfer R; Krenn K; Gmeiner M; Abraham D; Aharinejad S

2010-06-01

51

Effects of fibrin and alpha2-antiplasmin on plasminogen activation by staphylokinase.  

UK PubMed Central (United Kingdom)

Staphylokinase obtains plasminogen activating activity by forming a complex with plasminogen. Although the enzymatic activity of staphylokinase is enhanced by fibrin, how fibrin enhances enzymatic activity has not been determined yet. The effects of fibrin, or fibrinogen fragments, on the activation of plasminogen by staphylokinase was investigated using CNBr-digested fibrinogen fragments (FCB-2 and FCB-5) and plasmin-degraded cross-linked fibrin fragments ((DD)E complex, DD fragments and E fragments). Kinetic analysis of the activity of staphylokinase revealed that its plasminogen activating activity, which was expressed as kcat/Km, was enhanced by FCB-2 (10-fold) and FCB-5 (5-fold). These fibrin fragments caused 38-, 30-, and 8.5-fold increases in activity for the DD fragment, (DD)E complex and E fragment, respectively. Although alpha2-antiplasmin inhibited the activation of plasminogen by staphylokinase, FCB-2 abolished its inhibitory effects, and the plasminogen activating activity of staphylokinase was restored. The inhibitory effects of alpha2-antiplasmin on the activation of mini-plasminogen by staphylokinase were less than for Glu- or Lys-plasminogen, and the inhibitory effect of alpha2-antiplasmin was not altered by fibrin or EACA. These findings indicate that the staphylokinase/plasmin(ogen) complex reacts with fibrin even in the presence of alpha2-antiplasmin, and efficient plasminogen activation takes place on the surface of fibrin.

Okada K; Ueshima S; Takaishi T; Yuasa H; Fukao H; Matsuo O

1996-11-01

52

Expression of urokinase plasminogen activator and plasminogen activator inhibitor type-1 in ovarian cancer and its clinical significance.  

Science.gov (United States)

The urokinase plasminogen activator system, which consists of urokinase plasminogen activator (uPA), plasminogen activator inhibitor type-1 (PAI-1) and urokinase plasminogen activator receptor (uPAR), plays an important role in tumor invasion and metastasis, and it may be a potential diagnostic biomarker and therapeutic target in cancer. It has been found that the expression of uPA and PAI-1 in ovarian cancer is related to clinical pathologies, while their effects on the biological behavior of tumor cells and their clinical significance are still unknown. In this study, 100 tissue samples (60 samples from malignant tumors, 20 from benign tumors and 20 from controls) and 147 blood samples (49 samples each from patients with malignant tumors, benign tumors and control group, respectively) were analyzed. The positive expression levels of uPA and PAI-1 in the malignant tumor samples and their serum concentrations in the malignant group were all significantly higher than these levels in the benign tumors and controls. In addition, the levels in patients with poorly differentiated and stage III-IV cancers, cancers with metastases as well as residual tumors >2 cm after surgery, were all obviously increased, consistent with their concentrations in serum. The Cox model analysis showed that expression of uPA at the transcription level had significant associations with prognosis. In addition, uPA greatly enhanced the abilities of cell invasion, migration and adhesion through its overexpression in SKOV3 cells. Collectively, our results showed that uPA and PAI-1 play important roles in ovarian cancer development; therefore, their expression in tissues and their concentrations in serum would greatly assist the diagnosis and prediction of the prognosis in ovarian cancer. PMID:23174953

Zhang, Wei; Ling, Dan; Tan, Jie; Zhang, Jieqing; Li, Li

2012-11-20

53

The effect of fucoidan, heparin and cyanogen bromide-fibrinogen on the activation of human glutamic-plasminogen by tissue plasminogen activator.  

Science.gov (United States)

Earlier studies on the stimulatory effect of fucoidan, heparin, and cyanogen bromide (CNBr)-fibrinogen digest on the in-vitro activation of glutamic type plasminogen by tissue plasminogen activator, which were performed using subphysiologic ionic strengths of buffers, gave inconsistent results because of the variation in the ionic strengths of the buffers used. Studies were therefore conducted on the effect of these cofactors using 0.05 mol/l Tris buffer containing a physiologic concentration of sodium chloride. The double reciprocal plots of the activation of glutamic type plasminogen by tissue plasminogen activator in the presence of fucoidan and 6-aminohexanoic acid (6-AH) or heparin and 6-AH showed a four- to six-fold increase in K(cat), while the K(m) remained unchanged. On the other hand, there was greater than six-fold lowering of K(m) from 0.213 to 0.035 micromol/l in the presence of CNBr-fibrinogen, while K(cat) was only slightly increased. The ratios of the initial rate of plasmin generation in the presence or absence of the cofactors were plotted against the inverse of the volume fraction of glutamic type plasminogen or of tissue plasminogen activator after serial dilution. The results suggested that the enhancements by fucoidan and 6-AH or CNBr-fibrinogen were due to their interactions directed towards glutamic type plasminogen, while for heparin and 6-AH, the interaction was directed towards tissue plasminogen activator. Circular dichroism studies in the near ultraviolet range (250-308 nm) showed that 6-AH enhanced the circular dichroism spectra of glutamic type plasminogen around certain chromophores, while fucoidan and heparin had no effect, suggesting that the enhancement by the cofactors may be related to the favorable conformational changes of glutamic type plasminogen by 6-AH. PMID:12695744

Bell, Jason; Duhon, Shalisha; Doctor, Vasant M

2003-04-01

54

L-Mimosine and Dimethyloxaloylglycine Decrease Plasminogen Activation in Periodontal Fibroblasts.  

UK PubMed Central (United Kingdom)

Background: The use of prolyl hydroxylase (PHD) inhibitors such as L-mimosine and dimethyloxaloylglycine to improve angiogenesis is a new approach for periodontal regeneration. In addition to exhibiting pro-angiogenic effects PHD inhibitors can also modulate the plasminogen activator system in cells from non-oral tissues. Here we assessed the effect of PHD inhibitors on plasminogen activation by fibroblasts from the periodontium. Methods: Gingival and periodontal ligament fibroblasts were incubated with L-mimosine and dimethyloxaloylglycine. To investigate whether PHD inhibitors modulate the net plasminogen activation, kinetic assays were performed with and without interleukin (IL)-1. Moreover, plasminogen activators and the respective inhibitors were analyzed by casein zymography, immune assays, and quantitative polymerase chain reaction. Results: The kinetic assay showed that L-mimosine and dimethyloxaloylglycine reduced plasminogen activation under basal and IL-1-stimulated conditions. Casein zymographies revealed that the effect of L-mimosine involves a decrease in urokinase-type plasminogen activator activity. In agreement with these findings, reduced levels of urokinase-type plasminogen activator and elevated levels of plasminogen activator inhibitor-1 were observed. Conclusion: L-mimosine and dimethyloxaloylglycine can reduce plasminogen activation by fibroblasts from the gingiva and the periodontal ligament under basal conditions and in the presence of an inflammatory cytokine.

Wehner C; Gruber R; Agis H

2013-07-01

55

Hyperoxia increases plasminogen activator activity of cultured endothelial cells.  

UK PubMed Central (United Kingdom)

Confluent calf pulmonary artery endothelial monolayers exposed to 95% oxygen for 1, 2, or 3 days exhibit a time-dependent increase in adherence to substratum, which closely parallels changes in actin cytoarchitecture and the distribution of focal contact proteins vinculin and talin. Oxygen exposure also resulted in elevated plasminogen activator (PA) activity in conditioned media (CM) and in cytoskeletal protein- and focal contact protein-enriched fractions, with highest levels achieved in the latter two fractions at 48 h after oxygen exposure. PAs have been shown to participate in dismantling of extracellular matrix in a number of physiological and pathological situations. Immunocytochemical studies demonstrated extensive restructuring of matrix proteins collagen IV, laminin, and fibronectin, which correlated temporally with elevated PA levels. Further, when protease-containing cell fractions were used to study degradation of isolated matrices, those obtained from hyperoxia-exposed cells were substantially more active than those from normoxia-exposed cells. Our data suggest that hyperoxia-induced production of PA (and perhaps other proteases) may be partly responsible for degradation of the extracellular matrix of endothelial cells.

Phillips PG; Birnby L; Di Bernardo LA; Ryan TJ; Tsan MF

1992-01-01

56

Kinetic studies on the plasminogen activation by the staphylokinase-plasmin complex.  

UK PubMed Central (United Kingdom)

A pure complex of staphylokinase and plasmin was prepared by affinity chromatography with lysine-Sepharose, which enabled the simple analysis of the mechanism of plasminogen activation by staphylokinase. We used a truncated staphylokinase (SAK), which lacks the 10 amino acid residues at the NH2 terminal of native staphylokinase. The purity of this complex was confirmed by the native PAGE profile. Image analysis of the SDS-PAGE profile revealed that the molar ratio of plasmin and SAK in the complex was about 1:1. Using this SAK-plasmin complex, the kinetic parameters for the activation of Glu- or Lys-plasminogen were determined. The kinetic constant, kcat/Km, obtained when Lys-plasminogen was used as a substrate was approximately 10 times higher than that obtained when Glu-plasminogen was used. This plasminogen activation property of the SAK-plasmin complex was comparable to that of other plasminogen activators, such as streptokinase, urokinase, and tissue-type plasminogen activator (t-PA). This SAK-plasmin complex will simplify the elucidation of plasminogen activation by SAK. Through kinetic studies, the fibrin specificity and participation of plasminogen activator inhibitor will be clarified.

Shibata H; Nagaoka M; Sakai M; Sawada H; Watanabe T; Yokokura T

1994-04-01

57

Staphylokinase reduces plasmin formation by endogenous plasminogen activators.  

Science.gov (United States)

Hyperfibrinolysis is a consequence of imbalance between fibrinolytic activators and their inhibitors. Increased levels of circulating plasminogen (Plg) activators such as tissue- or urokinase-type plasminogen activators (tPA or uPA respectively) are the most common causes of hyperfibrinolysis, occasionally causing major hemorrhages. We found that staphylokinase (SAK), a well-known Plg activator of bacterial origin, inhibits Plg activation mediated by endogenous tPA and uPA. Furthermore, mixture of SAK with tPA led to a significantly reduced Plg-dependent fibrinolysis. This inhibitory effect was exerted through direct action of SAK on Plg rather than indirectly on tPA or uPA. Inhibition of Plg activation by SAK is readily abrogated by interaction of SAK with human neutrophil peptides (HNPs). Finally, we show that NH2-terminal residues of SAK are important for the inhibitory effect of SAK on tPA- and uPA-mediated Plg activation. In conclusion, SAK reduces tPA/uPA-mediated Plg activation by means of SAK.Plg complex formation, consequently downregulating tPA/uPA-induced fibrinolysis. PMID:18331597

Jin, Tao; Bokarewa, Maria; Zhu, Yihong; Tarkowski, Andrej

2008-03-10

58

Tissue-type plasminogen activator and plasminogen embedded in casein rule its degradation under physiological situations: manipulation with casein hydrolysate.  

Science.gov (United States)

The aims of this study were to test the assumption that tissue-type plasminogen activator (t-PA) and plasminogen (PG) are closely associated with the casein micelle and form a functional complex that rules casein degradation. This assumption was essentially verified for bovine milk under conditions wherein the plasmin system was activated by treatment with casein hydrolysate. It was also shown that urokinase-type PA (u-PA), the second type of plasminogen activator present in milk, was not involved in casein degradation. In agreement with previous studies, we show that treatment with casein hydrolysate precipitously reduced mammary secretion, disrupted the tight junction integrity (increase in Na+ and decrease in K+ concentrations), induced hydrolysis of casein, and activated various elements of the innate and acquired immune system. In the present study, we have identified t-PA as the principal PA, which is responsible for the conversion of PG to plasmin. It was found that t-PA and plasminogen are present in freshly secreted milk (less than 10 min from its secretion), suggesting that they are secreted as a complex by the mammary gland epithelial cells. Further research is needed to provide the direct evidence to verify this concept. PMID:23458975

Silanikove, Nissim; Shapiro, Fira; Merin, Uzi; Leitner, Gabriel

2013-03-05

59

Tissue-type plasminogen activator and plasminogen embedded in casein rule its degradation under physiological situations: manipulation with casein hydrolysate.  

UK PubMed Central (United Kingdom)

The aims of this study were to test the assumption that tissue-type plasminogen activator (t-PA) and plasminogen (PG) are closely associated with the casein micelle and form a functional complex that rules casein degradation. This assumption was essentially verified for bovine milk under conditions wherein the plasmin system was activated by treatment with casein hydrolysate. It was also shown that urokinase-type PA (u-PA), the second type of plasminogen activator present in milk, was not involved in casein degradation. In agreement with previous studies, we show that treatment with casein hydrolysate precipitously reduced mammary secretion, disrupted the tight junction integrity (increase in Na+ and decrease in K+ concentrations), induced hydrolysis of casein, and activated various elements of the innate and acquired immune system. In the present study, we have identified t-PA as the principal PA, which is responsible for the conversion of PG to plasmin. It was found that t-PA and plasminogen are present in freshly secreted milk (less than 10 min from its secretion), suggesting that they are secreted as a complex by the mammary gland epithelial cells. Further research is needed to provide the direct evidence to verify this concept.

Silanikove N; Shapiro F; Merin U; Leitner G

2013-05-01

60

[Characterization of urokinase type plasminogen activator modified by phenylglyoxal].  

Science.gov (United States)

A chemical modification of single-chain urokinase-type plasminogen activator (scu-PA) with phenylglyoxal under mild conditions resulted in the scu-PA derivatives with various numbers of the modified Arg residues. The study of properties of the resulting derivatives demonstrated that the modification of 4-12 Arg residues did not cause any loss of the activator, fibrinolytic, and potential amidase activities of the activator. The scu-PA with four modified Arg residues was found to be the most stable derivative in human blood plasma; it causes a more efficient lysis of plasma clots than the native activator. Three of four modified Arg residues are supposed to be within the 178RRHRGGS184 cluster, which was localized in the superficial loop of the scu-PA globule and was shown to interact with the complementary series of negatively charged residues in the molecule of the main plasma inhibitor PAI-1. The neutralization of positively charged Arg residues in this cluster decreases the affinity of scu-PA and the double chain urokinase-type plasminogen activator for PAI-1, which results in an enhancement of the stability in plasma and the fibrinolytic efficiency of the activator. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2002, vol. 28, no. 4; see also http://www.maik.ru. PMID:12197387

Mukhametova, L I; A?sina, R B; Lomakina, G Iu; Varfolomeev, S D

 
 
 
 
61

Structural and kinetic comparison of recombinant human single- and two-chain tissue plasminogen activator.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We examined the similarities and differences in conformation between recombinant human single-chain tissue plasminogen activator (sct-PA) and two-chain tissue plasminogen activator (tct-PA), and compared these structural data with measurement of enzymatic activity. The intrinsic protein fluorescence...

Loscalzo, J

62

Plasminogen activator in the rodent brain  

International Nuclear Information System (INIS)

[en] The cellular origin(s), the biochemical properties and the developmental pattern of the protease activator (PA) were investigated in the rodent brain. PA activity was localized in frozen brain sections by a novel autoradiographic technique. PA levels and electrophoretic mobility were determined in homogenates prepared from major regions of the developing and the mature brain, and both the localization and the specific activity of the enzyme were examined in X-irradiated brain regions. PA activity was shown to be correlated with cell bodies in neuronal-enriched regions and also with endothelial, meningeal and ependymal layers. PA levels increased in a transient manner and at different rates and time periods in the various brain regions that were analyzed. PA in neuronal, but not in epithelial cell layers was affected by X-irradiation and one of the brain PA species had a similar molecular weight to that of neuroblastoma cells. The authors' findings suggest that in the brain PA is produced by neurons and by epithelial cells, and that it may have additional functions to that of thrombolysis both in the developing and the mature brain. (Auth.)

1981-07-20

63

Arrhenius temperature dependence of in vitro tissue plasminogen activator thrombolysis  

Science.gov (United States)

Stroke is a devastating disease and a leading cause of death and disability. Currently, the only FDA approved therapy for acute ischemic stroke is the intravenous administration of the thrombolytic medication, recombinant tissue plasminogen activator (tPA). However, this treatment has many contraindications and can have dangerous side effects such as intra-cerebral hemorrhage. These treatment limitations have led to much interest in potential adjunctive therapies, such as therapeutic hypothermia (T ? 35 °C) and ultrasound enhanced thrombolysis. Such interest may lead to combining these therapies with tPA to treat stroke, however little is known about the effects of temperature on the thrombolytic efficacy of tPA. In this work, we measure the temperature dependence of the fractional clot mass loss ?m(T) resulting from tPA exposure in an in vitro human clot model. We find that the temperature dependence is well described by an Arrhenius temperature dependence with an effective activation energy Eeff of 42.0 ± 0.9 kJ mole?1. Eeff approximates the activation energy of the plasminogen-to-plasmin reaction of 48.9 kJ mole?1. A model to explain this temperature dependence is proposed. These results will be useful in predicting the effects of temperature in future lytic therapies.

Shaw, George J; Dhamija, Ashima; Bavani, Nazli; Wagner, Kenneth R; Holland, Christy K

2007-01-01

64

Arrhenius temperature dependence of in vitro tissue plasminogen activator thrombolysis  

International Nuclear Information System (INIS)

Stroke is a devastating disease and a leading cause of death and disability. Currently, the only FDA approved therapy for acute ischemic stroke is the intravenous administration of the thrombolytic medication, recombinant tissue plasminogen activator (tPA). However, this treatment has many contraindications and can have dangerous side effects such as intra-cerebral hemorrhage. These treatment limitations have led to much interest in potential adjunctive therapies, such as therapeutic hypothermia (T ? 35 deg. C) and ultrasound enhanced thrombolysis. Such interest may lead to combining these therapies with tPA to treat stroke, however little is known about the effects of temperature on the thrombolytic efficacy of tPA. In this work, we measure the temperature dependence of the fractional clot mass loss ?m(T) resulting from tPA exposure in an in vitro human clot model. We find that the temperature dependence is well described by an Arrhenius temperature dependence with an effective activation energy Eeff of 42.0 ± 0.9 kJ mole-1. Eeff approximates the activation energy of the plasminogen-to-plasmin reaction of 48.9 kJ mole-1. A model to explain this temperature dependence is proposed. These results will be useful in predicting the effects of temperature in future lytic therapies.

2007-06-07

65

Arrhenius temperature dependence of in vitro tissue plasminogen activator thrombolysis  

Energy Technology Data Exchange (ETDEWEB)

Stroke is a devastating disease and a leading cause of death and disability. Currently, the only FDA approved therapy for acute ischemic stroke is the intravenous administration of the thrombolytic medication, recombinant tissue plasminogen activator (tPA). However, this treatment has many contraindications and can have dangerous side effects such as intra-cerebral hemorrhage. These treatment limitations have led to much interest in potential adjunctive therapies, such as therapeutic hypothermia (T {<=} 35 deg. C) and ultrasound enhanced thrombolysis. Such interest may lead to combining these therapies with tPA to treat stroke, however little is known about the effects of temperature on the thrombolytic efficacy of tPA. In this work, we measure the temperature dependence of the fractional clot mass loss {delta}m(T) resulting from tPA exposure in an in vitro human clot model. We find that the temperature dependence is well described by an Arrhenius temperature dependence with an effective activation energy E{sub eff} of 42.0 {+-} 0.9 kJ mole{sup -1}. E{sub eff} approximates the activation energy of the plasminogen-to-plasmin reaction of 48.9 kJ mole{sup -1}. A model to explain this temperature dependence is proposed. These results will be useful in predicting the effects of temperature in future lytic therapies.

Shaw, George J [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Dhamija, Ashima [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Bavani, Nazli [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Wagner, Kenneth R [Department of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Holland, Christy K [Department of Biomedical Engineering, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States)

2007-06-07

66

Tissue plasminogen activator for treatment of livedoid vasculitis.  

Science.gov (United States)

Livedoid vasculitis, a hyalinizing vasculopathy, is characterized by extensive formation of microthrombi and deposition of fibrin in the middermal vessels, which result in epidermal infarction, ulceration, and formation of stellate scars. In a prospective study of nonhealing ulcers in patients with livedoid vasculitis, we found a high incidence of anticardiolipin antibodies, lupus anticoagulants, increased levels of plasminogen activator inhibitor, and low levels of endogenous tissue plasminogen activator (t-PA) activity. This procoagulant tendency and decreased fibrinolysis may provide an explanation for the occlusive vasculopathy often noted in biopsy specimens from these patients. On the basis of these findings, we proposed that fibrinolysis with recombinant t-PA would lyse microvascular thrombi, restore circulation, and promote wound healing. In six patients who had nonhealing ulcers caused by livedoid vasculitis and in whom numerous conventional therapies had failed, low-dose t-PA (10 mg) was administered intravenously during a 4-hour period daily for 14 days. Five of the six patients had dramatic improvement; almost complete healing of the ulcers occurred during hospitalization, and tissue oxygenation, as measured by transcutaneous oximetry, increased. The one treatment failure was due to rethrombosis of the microvasculature; this patient was subsequently re-treated but with concurrent anticoagulation, and her leg ulcers healed. We conclude that daily administration of a low dose of t-PA is safe and effective treatment for nonhealing ulcers due to occlusive vasculopathy. PMID:1434852

Klein, K L; Pittelkow, M R

1992-10-01

67

Tissue plasminogen activator for treatment of livedoid vasculitis.  

UK PubMed Central (United Kingdom)

Livedoid vasculitis, a hyalinizing vasculopathy, is characterized by extensive formation of microthrombi and deposition of fibrin in the middermal vessels, which result in epidermal infarction, ulceration, and formation of stellate scars. In a prospective study of nonhealing ulcers in patients with livedoid vasculitis, we found a high incidence of anticardiolipin antibodies, lupus anticoagulants, increased levels of plasminogen activator inhibitor, and low levels of endogenous tissue plasminogen activator (t-PA) activity. This procoagulant tendency and decreased fibrinolysis may provide an explanation for the occlusive vasculopathy often noted in biopsy specimens from these patients. On the basis of these findings, we proposed that fibrinolysis with recombinant t-PA would lyse microvascular thrombi, restore circulation, and promote wound healing. In six patients who had nonhealing ulcers caused by livedoid vasculitis and in whom numerous conventional therapies had failed, low-dose t-PA (10 mg) was administered intravenously during a 4-hour period daily for 14 days. Five of the six patients had dramatic improvement; almost complete healing of the ulcers occurred during hospitalization, and tissue oxygenation, as measured by transcutaneous oximetry, increased. The one treatment failure was due to rethrombosis of the microvasculature; this patient was subsequently re-treated but with concurrent anticoagulation, and her leg ulcers healed. We conclude that daily administration of a low dose of t-PA is safe and effective treatment for nonhealing ulcers due to occlusive vasculopathy.

Klein KL; Pittelkow MR

1992-10-01

68

Increased expression of the urokinase plasminogen activator system by Helicobacter pylori in gastric epithelial cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The gastric pathogen Helicobacter pylori (H. pylori) is linked to peptic ulcer and gastric cancer, but the relevant pathophysiological mechanisms are unclear. We now report that H. pylori stimulates the expression of plasminogen activator inhibitor (PAI)-1, urokinase plasminogen activator (uPA), and...

Kenny, Susan; Duval, Cedric; Sammut, Stephen J.; Steele, Islay; Pritchard, D. Mark; Atherton, John C.; Argent, Richard H.

69

Plasminogen activator inhibitor-1 deposition in the extracellular matrix of cultured human mesangial cells.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Human mesangial cells secrete tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1), the latter being secreted in large excess in vitro. We demonstrate that PAI-1 is a major component of the extracellular matrix of cultured human mesangial cells, where its deposition...

Hagège, J.; Peraldi, M. N.; Rondeau, E.; Adida, C.; Delarue, F.; Medcalf, R.; Schleuning, W. D.; Sraer, J. D.

70

Effects of hypoxia and reoxygenation on the expression levels of the urokinase-type plasminogen activator, its inhibitor plasminogen activator inhibitor type-1 and the urokinase-type plasminogen activator receptor in human head and neck tumour cells.  

UK PubMed Central (United Kingdom)

One aim during oncological radiation therapy is to induce reoxygenation in hypoxic tumours in order to enhance radiosensitivity and ultimately increase cell death. In squamous cell carcinomas of the head and neck (SCCHN), hypoxia is considered a pivotal physiological modulator for malignant progression, whereby the plasminogen activation system is involved in overlapping functions such as the shaping of the extracellular matrix, cell proliferation and signal transduction. Since little is known about reoxygenation and the plasminogen activation system in SCCHN, three human SCCHN cell lines (BHY, FaDu, and CAL27) and a non-transformed control cell line (VH7) were exposed to hypoxic (<0.5% O2) conditions for up to 72 h and subsequently reoxygenated for 24 h at normoxic conditions. The mRNA expression of the urokinase-type plasminogen activator (uPA), the plasminogen activator inhibitor type-1 (PAI-1) and the urokinase-type plasminogen activator receptor (uPAR) was assessed by means of real-time semi-quantitative RT-PCR, and the protein expression was determined by immunoenzymometric quantification (ELISA). Both hypoxia and reoxygenation induced statistically significant changes in uPA, PAI-1 and uPAR mRNA and protein levels in the various cell lines investigated, showing that oxygen tension is a strong modulator of the plasminogen activation system in vitro. However, no uniform correlation pattern was found between the mRNA and protein levels analysed over all three time-points (24, 48, and 72 h) and oxygen treatment variants (N, H, R) nor according to oxygen treatment conditions over all three time-points. Changes in oxygen tension could therefore be modulating the fragile balance between the various components of the plasminogen activation system in SSCHN ultimately leading to an increased tumour matrix disruption, alterations in cell invasiveness, and the dissemination of tumour cells to distant organs.

Sprague LD; Tomaso H; Mengele K; Schilling D; Bayer C; Stadler P; Schmitt M; Molls M

2007-05-01

71

Effect of staphylokinase-derived nonadecapeptide on the activation of plasminogen.  

Science.gov (United States)

Staphylokinase (SAK) expresses plasminogen activator (PA) activity by forming a complex with plasmin. The interaction between the plasmin-SAK complex and plasminogen was investigated using synthesized peptides, which were constructed according to the amino acid sequence of the SAK molecule. A synthetic nonadecapeptide (SAK22-40) corresponding to Glu22-Leu40 by the SAK molecule enhanced the activation of Glu-plasminogen by the plasmin-SAK complex. Analysis of IAsys resonant mirror biosensor showed that SAK22-40 bound to Glu-plasminogen. This binding was completely inhibited by IgG against the B-chain in the plasminogen molecule. But, this binding was not inhibited by IgG against lysine-binding sites (LBS) of the A-chain in the plasminogen molecule. The substitution of Lys35 with Ala in SAK22-40 did not enhance the activation of Glu-plasminogen by the plasmin-SAK complex. When SAK22-40 was administrated in a mouse thrombosis model, earlier recanalization was observed than in mice with vehicle administration. Thus, a newly synthesized peptide, SAK22-40 enhanced Glu-plasminogen activation and induced effective thrombolysis. PMID:17479190

Okada, Kiyotaka; Ueshima, Shigeru; Matsuno, Hiroyuki; Kawao, Naoyuki; Okamoto, Chikako; Tanaka, Masaki; Matsuo, Osamu

2007-05-01

72

Effect of oversulfated chondroitin-6-sulfate or oversulfated fucoidan in the activation of glutamic plasminogen by tissue plasminogen activator: role of lysine and cyanogen bromide-fibrinogen.  

Science.gov (United States)

Fucoidan and chondroitin-6-sulfate were oversulfated using chlorosulfonic acid-pyridine complex and were isolated as the sodium salt. Infrared analysis of oversulfated compounds showed introduction of sulfate groups in new positions, and in-vitro studies of the compounds showed a significant increase in the anticoagulant property. Addition of 28.6 microg/ml oversulfated compound gave a two-fold to four-fold increase in the rate of enhancement of activation of glutamic plasminogen by tissue plasminogen activator using 0.05 mol/l Tris buffer (pH 7.35) containing physiological concentrations of NaCl (0.9%). Under these conditions, unfractionated heparin was not active and the native compounds gave less than 30% enhancement. In the present study, the effect of lysine or cyanogen bromide-treated fibrinogen, alone or in combination with the oversulfated compounds, on the activation of glutamic plasminogen by tissue plasminogen activator was investigated. Addition of 16.2 mmol/l L-lysine gave three-fold to four-fold enhancement of activation, which was further enhanced to five-fold to six-fold by addition of 2.86 microg/ml oversulfated chondroitin-6-sulfate or oversulfated fucoidan. Cyanogen bromide-treated fibrinogen (50 microg/ml) gave a 10-fold enhancement of activation by itself, and addition of 2.86 microg/ml oversulfated compounds amplified this to 15-fold. A 25-fold to 35-fold enhancement of activation of glutamic plasminogen was obtained when 2.86 microg/ml oversulfated compounds were combined with 16.2 mmol/l lysine and 50 microg/ml cyanogen bromide-treated fibrinogen. Dilution studies showed that the amplification of the enhancement of lysine by 2.86 microg/ml oversulfated compound was related to interaction of the cofactors with both glutamic plasminogen and tissue plasminogen activator. PMID:18180617

Carranza, Yaneth E; Anderson, Dorian; Doctor, Vasant

2008-01-01

73

Recombinant tissue plasminogen activator for massive pulmonary thromboembolism.  

Science.gov (United States)

Pulmonary thromboembolism (PTE) can result in significant adverse maternal and fetal outcomes. Monteplase-a recombinant tissue plasminogen activator-is considered effective for the treatment of PTE; however, only a few reports have described cases wherein surgical procedures were performed following treatment with monteplase. Here, we present a patient diagnosed with a massive PTE at 28 weeks of gestation leading to maternal cardiac arrest and intrauterine fetal death. The patient was treated with percutaneous cardiopulmonary support and monteplase. Thrombolysis was achieved 30 min after its administration. The patient went into spontaneous labour and delivered a stillborn vaginally. Using gauze tamponade and uterotonic agents, haemostasis was achieved after 4 h, and bleeding completely ceased after 7 h. Thus, we suggest that a thrombolytic agent can be administered in critical cases, even if delivery is expected shortly. PMID:23709148

Samejima, Kouki; Takai, Yasushi; Matsumura, Hideyoshi; Seki, Hiroyuki

2013-05-23

74

Recombinant tissue plasminogen activator for massive pulmonary thromboembolism.  

UK PubMed Central (United Kingdom)

Pulmonary thromboembolism (PTE) can result in significant adverse maternal and fetal outcomes. Monteplase-a recombinant tissue plasminogen activator-is considered effective for the treatment of PTE; however, only a few reports have described cases wherein surgical procedures were performed following treatment with monteplase. Here, we present a patient diagnosed with a massive PTE at 28 weeks of gestation leading to maternal cardiac arrest and intrauterine fetal death. The patient was treated with percutaneous cardiopulmonary support and monteplase. Thrombolysis was achieved 30 min after its administration. The patient went into spontaneous labour and delivered a stillborn vaginally. Using gauze tamponade and uterotonic agents, haemostasis was achieved after 4 h, and bleeding completely ceased after 7 h. Thus, we suggest that a thrombolytic agent can be administered in critical cases, even if delivery is expected shortly.

Samejima K; Takai Y; Matsumura H; Seki H

2013-01-01

75

Structural and functional peculiarities of plasminogen activator inhibitor PAI-1  

Directory of Open Access Journals (Sweden)

Full Text Available PAI-1, an important component of the hemostasis system, is a specific inhibitor of both urokinase type and tissue type plasminogen activators. PAI-1 belongs to the serpin family. The interaction between somatomedin-like domain of vitronectin and PAI-1 leads to stabilization of the latter. PAI-1 latency transition is related to the conformational changes in the reactive central loop. The inhibitory mechanism of PAI-1 is in accordance with the classic scheme of serpin action. PAI-1 blocks the adhesion mediated by UPA and integrins, so this inhibitor plays an important role in adhesion process and angiogenesis. An altered PAI-1level is associated with the development of cardiovascular diseases, kidney fibrosis, diabetis, cancerogenesis.

Zhernossekov D. D.; Zolotareva E. N.; Kondratuk A. S.

2010-01-01

76

[Tissue plasminogen activator treatment of postvitrectomy pupillary fibrin membrane].  

UK PubMed Central (United Kingdom)

Twenty-five micrograms of human recombinant tissue plasminogen activator (tPA) was injected via the corneoscleral limbus of 14 postvitrectomy aphakic eyes with prominent pupillary fibrin membranes. Fibrinolysis by tPA was initiated by thirty minutes after the injection, and the fibrin membrane was completely dissolved within sixty minutes. No toxicity attributed to tPA was observed clinically. Intraocular fluid was obtained during fluid-gas exchange after complete dissolution of fibrin and analyzed for decomposed fibrin products (FDP). Intraocular FDP was significantly higher (160 +/- 250 micrograms/ml) than normal after tPA treatment. Intraocular tPA administration is a potent modality to treat postvitrectomy fibrin membrane. Fluid-gas exchange must be performed to eliminate as much FDP as possible to reduce postoperative inflammation.

Maeno T; Maeda N; Ikeda T; Tano Y

1991-11-01

77

Plasminogen fragment having activity to inhibit tumor metastasis and growth and process for preparing same technical field  

UK PubMed Central (United Kingdom)

The present invention provides a plasminogen fragment with the activity to inhibit tumor metastasis and growth, a process for preparing said fragment and an agent for inhibiting tumor metastasis and growth comprising said fragment as an active ingredient. The plasminogen fragment of the present invention is prepared from a elastase lysate of Lys-Plasminogen, which is produced by treating a natural plasminogen with plasmin, and preferably exhibits a strong heparin binding activity. The agent for inhibiting tumor metastasis and growth comprising the plasminogen fragment as an active ingredient of the present invention is useful for clinically treating solid cancers such as lung cancer or colon cancer.

MORIKAWA WATARU; MIYAMOTO SEIJI

78

Tissue plasminogen activator regulates Purkinje neuron development and survival.  

UK PubMed Central (United Kingdom)

The cerebellar cortex is centrally involved in motor coordination and learning, and its sole output is provided by Purkinje neurons (PNs). Growth of PN dendrites and their major synaptic input from granule cell parallel fiber axons takes place almost entirely in the first several postnatal weeks. PNs are more vulnerable to cell death than most other neurons, but the mechanisms remain unclear. We find that the homozygous nervous (nr) mutant mouse's 10-fold-increased cerebellar tissue plasminogen activator (tPA), a part of the tPA/plasmin proteolytic system, influences several different molecular mechanisms, each regulating a key aspect of postnatal PN development, followed by selective PN necrosis, as follows. (i) Excess endogenous or exogenous tPA inhibits dendritic growth in vivo and in vitro by activating protein kinase C? and phosphorylation of microtubule-associated protein 2. (ii) tPA/plasmin proteolysis impairs parallel fiber-PN synaptogenesis by blocking brain-derived neurotrophic factor/tyrosine kinase receptor B signaling. (iii) Voltage-dependent anion channel 1 (a mitochondrial and plasma membrane protein) bound with kringle 5 (a peptide derived from the excess plasminogen) promotes pathological enlargement and rounding of PN mitochondria, reduces mitochondrial membrane potential, and damages plasma membranes. These abnormalities culminate in young nr PN necrosis that can be mimicked in wild-type PNs by exogenous tPA injection into cerebellum or prevented by endogenous tPA deletion in nr:tPA-knockout double mutants. In sum, excess tPA/plasmin, through separate downstream molecular mechanisms, regulates postnatal PN dendritogenesis, synaptogenesis, mitochondrial structure and function, and selective PN viability.

Li J; Yu L; Gu X; Ma Y; Pasqualini R; Arap W; Snyder EY; Sidman RL

2013-06-01

79

[Fibrinolytic therapy of patients with pulmonary artery thromboembolism by tissue plasminogen activator and streptokinase preparations].  

Science.gov (United States)

Changes in clinical and hemodynamic indices, hemostatic system during therapy with plasminogen tissue activator and streptokinase drugs were studied in 49 patients with massive and submassive forms of pulmonary thromboembolism. Conduction of fibrinolytic therapy with plasminogen tissue activator vs streptokinase produced more marked and rapid change in the main hemodynamic parameters which characterized blood recovery in pulmonary artery. A correlation was revealed between the change in hemostatic system after thrombolytic therapy and development of hemorrhagic complications. Preferable introduction of plasminogen tissue activator is shown when thromboemboli locate in the trunk or in both main pulmonary arteries and in the presence of an occlusive lesion in lobular arteries. PMID:11210347

Ardashev, V N; Sokolianski?, N V; Bystrov, V V

2000-01-01

80

[Fibrinolytic therapy of patients with pulmonary artery thromboembolism by tissue plasminogen activator and streptokinase preparations  

UK PubMed Central (United Kingdom)

Changes in clinical and hemodynamic indices, hemostatic system during therapy with plasminogen tissue activator and streptokinase drugs were studied in 49 patients with massive and submassive forms of pulmonary thromboembolism. Conduction of fibrinolytic therapy with plasminogen tissue activator vs streptokinase produced more marked and rapid change in the main hemodynamic parameters which characterized blood recovery in pulmonary artery. A correlation was revealed between the change in hemostatic system after thrombolytic therapy and development of hemorrhagic complications. Preferable introduction of plasminogen tissue activator is shown when thromboemboli locate in the trunk or in both main pulmonary arteries and in the presence of an occlusive lesion in lobular arteries.

Ardashev VN; Sokolianski? NV; Bystrov VV

2000-01-01

 
 
 
 
81

Ultrasound affects distribution of plasminogen and tissue-type plasminogen activator in whole blood clots in vitro.  

UK PubMed Central (United Kingdom)

Ultrasound of 2 MHz frequency and 1.2 W/cm(2) acoustic intensity was applied to examine the effect of sonication on recombinant tissue-type plasminogen activator (rt-PA)-induced thrombolysis as well as on the distribution of plasminogen and t-PA within whole blood clots in vitro. Thrombolysis was evaluated quantitatively by measuring clot weight reduction and the level of fibrin degradation product D-dimer (FDP-DD) in the supernatant. Weight reduction in the group of clots treated both with ultrasound and rt-PA was 35.2% +/-6.9% which is significantly higher (p<0.0001) than in the group of clots treated with rt-PA only (19.9% +/-4.3%). FDP-DD level in the supernatants of the group treated with ultrasound and rt-PA increased sevenfold compared to the group treated with rt-PA alone, (14895 +/-2513 ng/ml vs. 2364 +/-725 ng/ml). Localization of fibrinolytic components within the clots was accomplished by using gel-entrapping technique and immunohistochemistry. Spatial distributions of t-PA and plasminogen showed clearly that ultrasound promoted the penetration of rt-PA into thrombi significantly (p<0.0001), and broadened the zone of lysis from 8.9 +/-2.6 microm to 21.2 +/-7.2 microm. We speculate that ultrasound enhances thrombolysis by affecting the distribution of rt-PA within the clot.

Devcic-Kuhar B; Pfaffenberger S; Gherardini L; Mayer C; Gröschl M; Kaun C; Benes E; Tschachler E; Huber K; Maurer G; Wojta J; Gottsauner-Wolf M

2004-11-01

82

Urokinase plasminogen activator and plasminogen activator inhibitor type-1 in nonsmall-cell lung cancer: relation to prognosis and angiogenesis.  

DEFF Research Database (Denmark)

BACKGROUND: Urokinase plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) have previously been suggested as prognostic markers in nonsmall-cell lung carcinomas (NSCLC). We investigate whether uPA and PAI-1 are prognostic markers in NSCLC and whether they are related to angiogenesis. MATERIALS AND METHODS: Frozen tumour tissue from surgical specimens from 118 previously untreated patients diagnosed with NSCLC in the period 1984-1991 were investigated. All patients were treated with surgery, and no chemo- or radiotherapy was given. UPA and PAI-1 levels were assessed using a sandwich ELISA method. RESULTS: Both uPA and PAI-1 were independent of classical histopathological parameters as well as of microvessel density and vascular pattern. Using death within the first 5 years as endpoint, neither of the factors were prognostic markers in univariate analysis, however, significantly higher levels of uPA and PAI-1 were seen in tumours with an angiogenic vascular pattern. In multivariate analysis, high disease stage (P<0.0001), adenocarcinoma (P=0.007), old age (P=0.02), and presence of an angiogenic pattern (P=0.05) were identified as independent markers of death within 5 years. CONCLUSIONS: The present study investigated the prognostic role of the protein levels of uPA and PAI-1 in 118 tumour specimens from patients diagnosed with NSCLC. Neither of the factors were identified as prognostic markers when evaluated with survival as endpoint. However, in tumours previously identified as non-angiogenic we found significantly lower contents of both uPA and PAI-1 as compared to angiogenic tumours, thus we hypothesize that uPA and PAI-1 stimulate angiogenesis in NSCLC. Udgivelsesdato: 2007-Apr

Offersen, Birgitte Vrou; Pfeiffer, Per

2007-01-01

83

Extracellular proteins of Lactobacillus crispatus enhance activation of human plasminogen.  

Science.gov (United States)

The abundant proteolytic plasminogen (Plg)/plasmin system is important in several physiological functions in mammals and also engaged by a number of pathogenic microbial species to increase tissue invasiveness or to obtain nutrients. This paper reports that a commensal bacterium, Lactobacillus crispatus, interacts with the Plg system. Strain ST1 of L. crispatus enhanced activation of human Plg by the tissue-type Plg activator (tPA), whereas enhancement of the urokinase-mediated Plg activation was lower. ST1 cells bound Plg, plasmin and tPA only poorly, and the Plg-binding and activation-enhancing capacities were associated with extracellular material released from the bacteria into buffer. The extracellular proteome of L. crispatus ST1 contained enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as major components. The enolase and the GAPDH genes of ST1 were cloned, sequenced and expressed in recombinant Escherichia coli as His(6)-fusion proteins, which bound Plg and enhanced its activation by tPA. Variable levels of secretion of enolase and GAPDH proteins as well as of the Plg activation cofactor function were detected in strains representing major taxonomic groups of the genus Lactobacillus. So far, interference with the Plg system has been addressed with pathogenic microbes. The results reported here demonstrate a novel interaction between a member of the microbiota and a major proteolytic system in humans. PMID:17379720

Hurmalainen, Veera; Edelman, Sanna; Antikainen, Jenni; Baumann, Marc; Lähteenmäki, Kaarina; Korhonen, Timo K

2007-04-01

84

Extracellular proteins of Lactobacillus crispatus enhance activation of human plasminogen.  

UK PubMed Central (United Kingdom)

The abundant proteolytic plasminogen (Plg)/plasmin system is important in several physiological functions in mammals and also engaged by a number of pathogenic microbial species to increase tissue invasiveness or to obtain nutrients. This paper reports that a commensal bacterium, Lactobacillus crispatus, interacts with the Plg system. Strain ST1 of L. crispatus enhanced activation of human Plg by the tissue-type Plg activator (tPA), whereas enhancement of the urokinase-mediated Plg activation was lower. ST1 cells bound Plg, plasmin and tPA only poorly, and the Plg-binding and activation-enhancing capacities were associated with extracellular material released from the bacteria into buffer. The extracellular proteome of L. crispatus ST1 contained enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as major components. The enolase and the GAPDH genes of ST1 were cloned, sequenced and expressed in recombinant Escherichia coli as His(6)-fusion proteins, which bound Plg and enhanced its activation by tPA. Variable levels of secretion of enolase and GAPDH proteins as well as of the Plg activation cofactor function were detected in strains representing major taxonomic groups of the genus Lactobacillus. So far, interference with the Plg system has been addressed with pathogenic microbes. The results reported here demonstrate a novel interaction between a member of the microbiota and a major proteolytic system in humans.

Hurmalainen V; Edelman S; Antikainen J; Baumann M; Lähteenmäki K; Korhonen TK

2007-04-01

85

The role of carbohydrate side chains of plasminogen in its activation by staphylokinase.  

Science.gov (United States)

Kinetic parameters (k(Pg) and K(Pg)) were determined for activation of Glu-plasminogen (Glu-Pg) and Lys-plasminogen (Lys-Pg) type I (with N-linked carbohydrate chain at Asn-289) and type II (with unsubstituted Asn-289) by plasmin-staphylokinase (Pm-STA) complex. The K(Pg) values for Glu-Pg I and Lys-Pg I (17.1 and 11.2 microM, respectively) were higher than those for Glu-Pg II and Lys-Pg II (14.9 and 5.4 microM, respectively), while only minor differences in the k(Pg) values were observed between plasminogens type I and type II. Soluble fibrin significantly increased the k(Pg)/K(Pg) values for activation of all four plasminogens due to a decrease in the K(Pg) values but did not alter the k(Pg) values. However, the activation of plasminogens type I was stimulated by fibrin lesser degree than that of plasminogens type II. These findings indicate that N-glycosylation of kringle 3 of plasminogen decreases the stability of Pm-STA-Pg ternary enzyme-substrate complex in solution as well as interferes with its formation and rearrangement on the fibrin surface. PMID:16176856

Aisina, Roza; Mukhametova, Liliya; Gershkovich, Karina; Varfolomeyev, Sergei

2005-10-10

86

Growth of ovine granulocyte-macrophage precursors in vitro without exogenous colony-stimulating activity  

Energy Technology Data Exchange (ETDEWEB)

Ovine granulocyte-macrophage colony-forming units (CFU-GM) from peripheral blood and bone marrow were cultured in vitro. The colony-stimulating activity (CSA) was provided by various conditioned-media previously reported to contain CSA and by homologous sheep serum (SS). The maximum number of CFU-GM was observed in the cultures containing SS without the addition of exogenous CSA. The CFU-GM appeared earlier in the cultures containing bone marrow cells when compared to the peripheral blood CFU-GM. Replacement of SS by bovine fetal serum resulted in suboptimal growth of ovine CFU-GM.

Chandra, P.; Joel, D.D.; Chanana, A.D.

1983-11-01

87

Effect of the extracellular matrix on plasminogen activator isozyme activities of human mammary epithelial cells in culture.  

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Multiple molecular forms of plasminogen activator were detected in normal human mammary epithelial cells in culture. Cells derived from (normal) breast mammoplasty specimens and grown on the surface of collagen gels exhibited three major classes of plasminogen activator isozymes (Mr = 100,000 [100K]...

Yang, N S; Park, C; Longley, C; Furmanski, P

88

Plasminogen activation by airway smooth muscle is regulated by type I collagen.  

UK PubMed Central (United Kingdom)

Plasmin, the activated protease product of plasminogen, is involved in collagen remodeling, and is strongly implicated in asthma pathophysiology by recent genome-wide association studies. This study examines plasminogen "activation" by airway smooth muscle cells, and its regulation in a fibrotic environment created by culture on type I collagen and incubation with transforming growth factor (TGF)-?. Urokinase plasminogen activator (uPA) activity was detected in the supernatants of human airway smooth muscle cell cultures maintained in serum-free conditions. Incubation with plasminogen (1.5-50.0 ?g/ml, 24 h) increased plasmin activity in a concentration-dependent manner (P < 0.001). uPA activity was higher in cultures maintained on fibrillar type I collagen substrata than in those on plastic, as was plasmin activity after incubation with plasminogen (20 ?g/ml). Pretreatment with TGF-? (100 pM) for 18 hours inhibited plasminogen activation by airway smooth muscle cells maintained on plastic, but not on collagen. TGF-? stimulated an increase in the level of uPA mRNA in airway smooth muscle cells grown on collagen, but not on plastic. Reducing the levels of ?1-integrin collagen receptor, using interference RNA, attenuated plasmin formation by airway smooth muscle cells grown on collagen, and restored the inhibitory effect of TGF-?. This study shows that airway smooth muscle activation of plasminogen by uPA is accelerated in a collagen-rich environment in which the inhibitory effect of TGF-? is attenuated in association with greater uPA expression induced via ?1-integrin signaling. These findings suggest that the plasminogen-activation system involving uPA has the potential to contribute to airway wall remodeling in asthma.

Schuliga M; Harris T; Stewart AG

2011-06-01

89

Vampire bat plasminogen activator DSPA-alpha-1 (desmoteplase): a thrombolytic drug optimized by natural selection.  

Science.gov (United States)

Plasminogen activators are enzymes found in all vertebrate species investigated so far. Their physiological function is the generation of localized proteolysis in the context of tissue remodeling, wound healing and neuronal plasticity. The common vampire bat (Desmodus rotundus) is a New World species that feeds exclusively on blood. Its saliva contains highly potent plasminogen activators, specialized in rapid lysis of fresh blood clots. Biochemical and pharmacological evidence indicates that these plasminogen activators represent a new class of thrombolytics with pharmacological and toxicological properties superior to human tissue-type plasminogen activator, the clot dissolving agent now most frequently used in medicine. A form of the enzyme produced by recombinant DNA technology is currently employed to test this hypothesis in clinical studies. PMID:11910176

Schleuning, W D

90

Soluble urokinase plasminogen activator receptor is associated with subclinical organ damage and cardiovascular events  

DEFF Research Database (Denmark)

The soluble urokinase plasminogen activator receptor (suPAR) is a plasma marker of low grade inflammation and has been associated with cardiovascular risk. We wanted to investigate whether suPAR was associated with markers of subclinical organ damage.

Sehestedt, T; Lyngbæk, S

2011-01-01

91

Turnover of tissue plasminogen activator in normal and hepatectomized rabbits  

Energy Technology Data Exchange (ETDEWEB)

The distribution, and clearance of the tissue plasminogen activator (tPA) was studied in rabbits, rats and mice. Following an intravenous injection of I-labelled tPA a large portion of the radioactive dose was rapidly accumulated in the liver. After one hour the radioactivity in the liver was less than 5 per cent of the injected dose. The highest activity was then found in the intestine, stomach and in the blood. Gel filtration of plasma taken one hour after the injection revealed that the major part (60%) of the radioactivity was present as low molecular weight metabolites or free iodine. The remaining activity was present as high molecular weight inhibitor complexes (26%) or as free tPA (15%). In order to study in vivo reactions between tPA and plasma inhibitors without hepatic interference, plasma turnover was also studied in hepatectomized rabbits. High amounts of radioactivity remained in the plasma after one hour. Gel filtration of this plasma revealed that 54 per cent of the radioactivity was bound to inhibitors, 34 per cent circulated as free tPA while a minor portion (12%) was found as free iodine or metabolites. The half-life of fibrinolytically active tPA in hepatectomized rabbits was 40 minutes compared to 2 minutes in intact rabbits. The increase in the half-life of tPA in hepatectomized rabbits also resulted in an improved thrombolytic effect after treatment with 0.5 mg tPA.

Nilsson, S.; Einarsson, M.; Ekvaern, S.H.; Haeggroth, L.M.; Mattsson, C.

1985-08-15

92

Thrombin activatable fibrinolysis inhibitor (TAFI) affects fibrinolysis in a plasminogen activator concentration-dependent manner. Study of seven plasminogen activators in an internal clot lysis model.  

Science.gov (United States)

TAFIa was shown to attenuate fibrinolysis. In our in vitro study, we investigated how the inhibitory effect of TAFIa depended on the type and concentration of the plasminogen activator (PA). We measured PA-mediated lysis times of plasma clots under conditions of maximal TAFI activation by thrombin-thrombo-modulin in the absence and presence of potato carboxypeptidase inhibitor. Seven different PAs were compared comprising both tPA-related (tPA, TNK-tPA, DSPA), bacterial PA-related (staphylokinase and APSAC) and urokinase-related (tcu-PA and k2tu-PA) PAs. The lysis times and the retardation factor were plotted against the PA concentration. The retardation factor plots were bell-shaped. At low PA concentrations, the retardation factor was low, probably due to the limited stability of TAFIa. At intermediate PA concentrations the retardation factor was maximal (3-6 depending on the PA), with TNK-tPA, APSAC and DSPA exhibiting the strongest effect. At high PA concentrations, the retardation factor was again low, possibly due to inactivation of TAFIa by plasmin or to a complete conversion of glu-plasminogen into lys-plasminogen. Using individual plasmas with a reduced plasmin inhibitor activity (plasmin inhibitor Enschede) the bell-shaped curve of the retardation factor shifted towards lower tPA and DSPA concentrations, but the height did not decrease. In conclusion, TAFIa delays the lysis of plasma clots mediated by all the plasminogen activators tested. This delay is dependent on the type and concentration of the plasminogen activator, but not on the fibrin specificity of the plasminogen activator. Furthermore, plasmin inhibitor does not play a significant role in the inhibition of plasma clot lysis by TAFI. PMID:14983222

Guimarães, Ana H C; Rijken, Dingeman C

2004-03-01

93

Post-vitrectomy tissue plasminogen activator injection for central retinal vein occlusion.  

UK PubMed Central (United Kingdom)

Three patients with recent central retinal vein occlusion underwent vitrectomy, fluid-air exchange, and a 50-microg tissue plasminogen activator intravitreal injection. After a mean follow-up period of 38.7 weeks, no patient's vision improved and one patient required an additional vitrectomy. Post-vitrectomy tissue plasminogen activator injection did not improve the course of central retinal vein occlusion in these three cases.

Christodoulakis EV; Tsilimbaris MK

2008-05-01

94

Transgenic chickens expressing human urokinase-type plasminogen activator.  

Science.gov (United States)

Urokinase-type plasminogen activator is a serine protease that is clinically used in humans for the treatment of thrombolytic disorders and vascular diseases such as acute ischemic stroke and acute peripheral arterial occlusion. This study explored the feasibility of using chickens as a bioreactor for producing human urokinase-type plasminogen activator (huPA). Recombinant huPA gene, under the control of a ubiquitous Rous sarcoma virus promoter, was injected into the subgerminal cavity of freshly laid chicken eggs at stage X using the replication-defective Moloney murine leukemia virus (MoMLV)-based retrovirus vectors encapsidated with VSV-G (vesicular stomatitis virus G) glycoprotein. A total of 38 chicks, out of 573 virus-injected eggs, hatched and contained the huPA gene in their various body parts. The mRNA transcript of the huPA gene was present in various organs, including blood and egg, and was germ-line transmitted to the next generation. The level of active huPA protein was 16-fold higher in the blood of the transgenic chicken than in the nontransgenic chicken (P < 0.05). The expression of huPA protein in eggs increased from 7.82 IU/egg in the G0 generation to 17.02 IU/egg in the G1 generation. However, huPA-expressing embryos had reduced survival and hatchability at d 18 and 21 of incubation, respectively, and the blood clotting time was significantly higher in transgenic chickens than their nontransgenic counterparts (P < 0.05). Furthermore, adult transgenic rooster showed reduced (P < 0.05) fertility, as revealed by reduced volume of semen ejaculate, sperm concentration, and sperm viability. Taken together, our data suggest that huPA transgenic chickens could be successfully produced by the retroviral vector system. Transgenic chickens, expressing the huPA under the control of a ubiquitous promoter, may not only be used as a bioreactor for pharming of the huPA drug but also be useful for studying huPA-induced bleeding and other disorders. PMID:23960123

Lee, Sung Ho; Gupta, Mukesh Kumar; Ho, Young Tae; Kim, Teoan; Lee, Hoon Taek

2013-09-01

95

Simple and sensitive assay employing stable reagents for quantification of plasminogen activator  

Energy Technology Data Exchange (ETDEWEB)

A simple and sensitive indirect assay for quantifying plasminogen activator using (/sup 3/H)-casein as substrate is described. The assay has been used to measure plasminogen activators from various sources including bacteria, cultured cells, and human plasma. The assay is linear with respect to concentration of plasminogen activator and time of incubation and is independent of concentration of plasminogen. The assay can routinely be used to quantify as few as 8 X 10(-3) international units ml-1 of streptokinase. Results obtained with the (/sup 3/H)-casein assay correlate well with those obtained by the fibrin plate method (R . 0.83 by Spearman's ranked co-efficient of correlation). The reagents are extremely stable and easily stored. The ease with which the assay can be performed gives the clinical laboratory the potential to test large numbers of patients upon short notice and within a short period of time.

Lewis, J.G.; Pizzo, S.V.; Adams, D.O.

1981-01-01

96

Human breast cancer cell-mediated bone collagen degradation requires plasminogen activation and matrix metalloproteinase activity  

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Full Text Available Abstract Background Breast cancer cells frequently metastasize to the skeleton and induce extensive bone destruction. Cancer cells produce proteinases, including matrix metalloproteinases (MMPs) and the plasminogen activator system (PAS) which promote invasion of extracellular matrices, but whether these proteinases degrade bone matrix is unclear. To characterize the role that breast cancer cell proteinases play in bone degradation we compared the effects of three human breast cancer cell lines, MDA-MB-231, ZR-75-1 and MCF-7 with those of a normal breast epithelial cell line, HME. The cell lines were cultured atop radiolabelled matrices of either mineralized or non-mineralized bone or type I collagen, the principal organic constituent of bone. Results The 3 breast cancer cell lines all produced significant degradation of the 3 collagenous extracellular matrices (ECMs) whilst the normal breast cell line was without effect. Breast cancer cells displayed an absolute requirement for serum to dissolve collagen. Degradation of collagen was abolished in plasminogen-depleted serum and could be restored by the addition of exogenous plasminogen. Localization of plasmin activity to the cell surface was critical for the degradation process as aprotinin, but not ?2 antiplasmin, prevented collagen dissolution. During ECM degradation breast cancer cell lines expressed urokinase-type plasminogen activator (u-PA) and uPA receptor, and MMPs-1, -3, -9,-13, and -14. The normal breast epithelial cell line expressed low levels of MMPs-1, and -3, uPA and uPA receptor. Inhibitors of both the PAS (aprotinin and PA inhibitor-1) and MMPs (CT1166 and tisue inhibitor of metalloproteinase) blocked collagen degradation, demonstrating the requirement of both plasminogen activation and MMP activity for degradation. The activation of MMP-13 in human breast cancer cells was prevented by plasminogen activator inhibitor-1 but not by tissue inhibitor of metalloproteinase-1, suggesting that plasmin activates MMP-13 directly. Conclusions These data demonstrate that breast cancer cells dissolve type I collagen and that there is an absolute requirement for plasminogen activation and MMP activity in the degradation process.

Morgan Hayley; Hill Peter A

2005-01-01

97

Cathepsin D stimulates the activities of secreted plasminogen activators in the breast cancer acidic environment.  

UK PubMed Central (United Kingdom)

Two proteases cathepsin D (cath D) and urokinase plasminogen activator (uPA) are tissue markers associated with an increased risk of metastasis in breast cancer. We investigated whether cath D, the major aspartyl protease overexpressed by breast cancer cells can trigger a proteolytic cascade via activation of plasminogens at the extracellular pH measured in hypoxic tumors. The effects of the aspartyl protease inhibitor pepstatin on the plasminogen activator (PA) system were analysed by conditioning media of human MDA-MB231 breast cancer cells at pH 6.6 and pH 7.4. Zymography analysis of culture media showed that pepstatin inhibited the secreted activity of tissue-type plasminogen activator (tPA) but not that of uPA. tPA was identified on the basis of the molecular weight, the immunoreactivity with relevant antibodies and the resistance to amiloride, a specific uPA inhibitor. The secreted tPA activity measured by a chromogenic assay in the presence of amiloride was also inhibited by pepstatin at pH 6.6. Surprisingly, pepstatin did not affect secreted tPA protein concentration but markedly increased the amount of the secreted plasminogen activator inhibitor-1 (PAI-1). We conclude that cath D overexpressed by these cells, stimulates at pH 6.6, but not at neutral pH, the extracellular PA proteolytic activity indirectly via PAI-1 proteolysis. This suggests that cath D at acidic pH close to the hypoxic regions of solid tumors, contributes to trigger a proteolytic cascade facilitating cancer cell invasion and metastasis.

Maynadier M; Farnoud R; Lamy PJ; Laurent-Matha V; Garcia M; Rochefort H

2013-11-01

98

Cathepsin D stimulates the activities of secreted plasminogen activators in the breast cancer acidic environment.  

Science.gov (United States)

Two proteases cathepsin D (cath D) and urokinase plasminogen activator (uPA) are tissue markers associated with an increased risk of metastasis in breast cancer. We investigated whether cath D, the major aspartyl protease overexpressed by breast cancer cells can trigger a proteolytic cascade via activation of plasminogens at the extracellular pH measured in hypoxic tumors. The effects of the aspartyl protease inhibitor pepstatin on the plasminogen activator (PA) system were analysed by conditioning media of human MDA-MB231 breast cancer cells at pH 6.6 and pH 7.4. Zymography analysis of culture media showed that pepstatin inhibited the secreted activity of tissue-type plasminogen activator (tPA) but not that of uPA. tPA was identified on the basis of the molecular weight, the immunoreactivity with relevant antibodies and the resistance to amiloride, a specific uPA inhibitor. The secreted tPA activity measured by a chromogenic assay in the presence of amiloride was also inhibited by pepstatin at pH 6.6. Surprisingly, pepstatin did not affect secreted tPA protein concentration but markedly increased the amount of the secreted plasminogen activator inhibitor-1 (PAI-1). We conclude that cath D overexpressed by these cells, stimulates at pH 6.6, but not at neutral pH, the extracellular PA proteolytic activity indirectly via PAI-1 proteolysis. This suggests that cath D at acidic pH close to the hypoxic regions of solid tumors, contributes to trigger a proteolytic cascade facilitating cancer cell invasion and metastasis. PMID:24026424

Maynadier, Marie; Farnoud, Reza; Lamy, Pierre-Jean; Laurent-Matha, Valérie; Garcia, Marcel; Rochefort, Henri

2013-09-10

99

Role of tissue plasminogen activator in acute ischemic stroke.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To evaluate the literature regarding the use of intravenous tissue plasminogen activator (tPA) in the treatment of acute ischemic stroke, focusing on the appropriate usage criteria and administration time window. DATA SOURCES: A PubMed and MEDLINE search was performed (1990-November 2010) using the key words alteplase, tissue plasminogen activator, thrombolytic, ischemic stroke, and cerebrovascular accident. STUDY SELECTION AND DATA EXTRACTION: Clinical trials published in English were evaluated and relevant primary literature evaluating the use of tPA in acute ischemic stroke was included. DATA SYNTHESIS: The NINDS (National Institute of Neurological Disorders and Stroke) trial revealed clinical efficacy of tPA in the treatment of acute ischemic stroke when administered within 3 hours of stroke symptom onset and served as the foundation for the American Heart Association/American Stroke Association (AHA/ASA) acute ischemic stroke guideline recommendations. The ECASS (European Cooperative Acute Stroke Study) I, ECASS II, and ATLANTIS (Alteplase Thrombolysis for Acute Noninterventional Therapy in Ischemic Stroke), part A and B, trials each assessed the efficacy of tPA when administered beyond 3 hours of ischemic stroke onset, but the results of each trial did not support its use beyond 3 hours. The ECASS III trial showed clinical efficacy of tPA when administered up to 4.5 hours. The SITS-MOST (Safe Implementation of Thrombolysis in Stroke-Monitoring Study) and SITS-ISTR (Safe Implementation of Thrombolysis in Stroke International Stroke Thrombolysis Register) registries evaluated the safety and efficacy of tPA at both 3 and 4.5 hours and showed promising results. In 2009, the AHA/ASA stroke guidelines were updated to support the use of tPA in select patients up to 4.5 hours after symptom onset. CONCLUSIONS: tPA is effective when administered up to 4.5 hours after ischemic stroke symptom onset in select patients. However, timely administration remains paramount to achievement of optimal therapeutic outcomes.

Hatcher MA; Starr JA

2011-03-01

100

Modulation of zinc toxicity by tissue plasminogen activator.  

UK PubMed Central (United Kingdom)

The tissue plasminogen activator (tPA)-plasmin proteolytic system mediates excitotoxin-induced neurodegeneration in vivo and in cell culture. tPA also confers neuroprotection from zinc toxicity in cell culture through a proteolysis-independent mechanism. This raises two questions: what is this non-enzymatic mechanism, and why tPA does not synergize with zinc to promote neuronal cell death? We show here that zinc binds to tPA and inhibits its activity in a dose-dependent fashion, thus terminating its protease-dependent neurotoxic capacity. We extend the previously reported culture findings to demonstrate that elevated zinc is neurotoxic in vivo, and even more so when tPA is absent. Thus, physiological levels of tPA confer protection from elevated free zinc. Mechanistically, tPA promotes movement of zinc into hippocampal neuron cells through voltage-sensitive Ca(2+) channels and Ca(2+)-permeable AMPA/KA channels. Therefore, zinc and tPA each appear to be able to limit the potential of the other to facilitate neurodegeneration, a reciprocal set of actions that may be critical in the hippocampus where tPA is secreted during the nonpathological conditions of learning and memory at sites known to be repositories of free and sequestered zinc.

Siddiq MM; Tsirka SE

2004-01-01

 
 
 
 
101

Tissue plasminogen activator prevents white matter damage following stroke.  

Science.gov (United States)

Tissue plasminogen activator (tPA) is the only available treatment for acute stroke. In addition to its vascular fibrinolytic action, tPA exerts various effects within the brain, ranging from synaptic plasticity to control of cell fate. To date, the influence of tPA in the ischemic brain has only been investigated on neuronal, microglial, and endothelial fate. We addressed the mechanism of action of tPA on oligodendrocyte (OL) survival and on the extent of white matter lesions in stroke. We also investigated the impact of aging on these processes. We observed that, in parallel to reduced levels of tPA in OLs, white matter gets more susceptible to ischemia in old mice. Interestingly, tPA protects murine and human OLs from apoptosis through an unexpected cytokine-like effect by the virtue of its epidermal growth factor-like domain. When injected into aged animals, tPA, although toxic to the gray matter, rescues white matter from ischemia independently of its proteolytic activity. These studies reveal a novel mechanism of action of tPA and unveil OL as a target cell for cytokine effects of tPA in brain diseases. They show overall that tPA protects white matter from stroke-induced lesions, an effect which may contribute to the global benefit of tPA-based stroke treatment. PMID:21576385

Correa, Fernando; Gauberti, Maxime; Parcq, Jérôme; Macrez, Richard; Hommet, Yannick; Obiang, Pauline; Hernangómez, Miriam; Montagne, Axel; Liot, Géraldine; Guaza, Carmen; Maubert, Eric; Ali, Carine; Vivien, Denis; Docagne, Fabian

2011-05-16

102

The interaction of streptokinase.plasminogen activator complex, tissue-type plasminogen activator, urokinase and their acylated derivatives with fibrin and cyanogen bromide digest of fibrinogen. Relationship to fibrinolytic potency in vitro.  

Science.gov (United States)

The effects of purified soluble fibrin and of fibrinogen fragments (fibrin mimic) on the activation of Lys-plasminogen (i.e. plasminogen residues 77-790) to plasmin by streptokinase.plasminogen activator complex and by tissue-type plasminogen activator were studied. Dissociation constants of both activators were estimated to lie in the range 90-160 nM (fibrin) and 16-60 nM (CNBr-cleavage fragments of fibrinogen). The kinetic mechanism for both types of activator comprised non-essential enzyme activation via a Rapid Equilibrium Ordered Bireactant sequence. In order to relate the fibrin affinity of plasminogen activators to their fibrinolytic potency, the rate of lysis of supported human plasma clots formed in the presence of unmodified or active-centre-acylated precursors of plasminogen activators was studied as a function of the concentration of enzyme derivative. The concentrations of unmodified enzyme giving 50% lysis/h in this assay were 0.9, 2.0 and 11.0 nM for tissue-type plasminogen activator, streptokinase.plasmin(ogen) and urokinase respectively. However, the potencies of active-centre-acylated derivatives of these enzymes suggested that acylated-tissue plasminogen activator and streptokinase.plasminogen complexes of comparable hydrolytic stability were of comparable potency. Both types of acyl-enzyme were significantly more potent than acyl-urokinases.

Cassels, R; Fears, R; Smith, R A

1987-01-01

103

Plasma plasminogen activator inhibitor 1, insulin resistance and android obesity.  

Science.gov (United States)

Plasma plasminogen activator inhibitor 1 (PAI-1) levels are elevated in insulin-resistant subjects and are associated with increased cardiovascular risk of atherothrombosis. Strong association between PAI-1 and the metabolic components of the insulin resistance syndrome is found in clinical studies, suggesting that insulin resistance may regulate circulating PAI-1. However, the mechanisms underlying increased PAI-1 levels in such conditions are still poorly understood. Several studies have been carried out specifically in patients with central or android obesity, a major characteristic of the insulin resistance syndrome, and have suggested that visceral adipose tissue may be the major component of the relationship between android obesity and PAI-1. Accordingly, adipose tissue PAI-1 production was found to be elevated in obese human subjects, particularly in visceral adipose tissue. The genetic background for having high PAI-1 levels in several populations have been looked for and its role appeared to be weaker than that of the metabolic condition. High plasma PAI-1 levels are then clearly related to android obesity and insulin resistance, but the mechanisms whereby PAI-1 increases in plasma in these diseases remain to be determined. PMID:10665338

Bastard, J P; Piéroni, L

1999-12-01

104

Plasma plasminogen activator inhibitor 1, insulin resistance and android obesity.  

UK PubMed Central (United Kingdom)

Plasma plasminogen activator inhibitor 1 (PAI-1) levels are elevated in insulin-resistant subjects and are associated with increased cardiovascular risk of atherothrombosis. Strong association between PAI-1 and the metabolic components of the insulin resistance syndrome is found in clinical studies, suggesting that insulin resistance may regulate circulating PAI-1. However, the mechanisms underlying increased PAI-1 levels in such conditions are still poorly understood. Several studies have been carried out specifically in patients with central or android obesity, a major characteristic of the insulin resistance syndrome, and have suggested that visceral adipose tissue may be the major component of the relationship between android obesity and PAI-1. Accordingly, adipose tissue PAI-1 production was found to be elevated in obese human subjects, particularly in visceral adipose tissue. The genetic background for having high PAI-1 levels in several populations have been looked for and its role appeared to be weaker than that of the metabolic condition. High plasma PAI-1 levels are then clearly related to android obesity and insulin resistance, but the mechanisms whereby PAI-1 increases in plasma in these diseases remain to be determined.

Bastard JP; Piéroni L

1999-12-01

105

Streptokinase and tissue plasminogen activator in acute myocardial infarction.  

UK PubMed Central (United Kingdom)

The use of thrombolytic agents for the treatment of myocardial infarction is increasing. Many community hospitals are infusing SK intravenously and those with cardiac catheterization laboratories often use intracoronary SK and angioplasty. Tissue plasminogen activator is undergoing extensive clinical trials, and reports of this research should add to our knowledge of this new therapy. Recently, benefits from thrombolytic therapy such as increased ejection fraction, improved regional wall motion, and short-term decreases in mortality have been documented. Both the GISSI trial that recruited 11,712 patients in Italy and the Netherlands trial documented significant short-term decreases in mortality after therapy with SK compared with control groups. As this information reaches the medical community, we may see an increase in the use of thrombolytic therapy during acute myocardial infarction. Additionally, community education service organizations should reemphasize the importance of seeking help early after the signs and symptoms of acute myocardial infarction appear to promote early treatment and potential salvage of greater amounts of myocardium. The long-term prognosis of patients who have been successfully reperfused and the best management after thrombolytic therapy is not yet known. Future problems and benefits from this therapy are still to be determined.

Brewer CC; Markis JE

1986-11-01

106

Relationship of tissue plasminogen activator, plasminogen activator inhibitor-1 and fibrinogen with coronary artery disease in South Indian male subjects.  

UK PubMed Central (United Kingdom)

AIM: Prevalence rates of coronary artery disease (CAD) are reported to be very high in Asian Indians. Conventional risk factors do not explain the high rates of CAD among Indians. Recently, several newer risk factors have been reported to be associated with CAD. We measured tissue plasminogen activator (tPA) antigen, plasminogen activator inhibitor-1 (PAI-1) and fibrinogen levels in South Indian diabetic and non-diabetic subjects with and without CAD. METHODS: Four groups of subjects were studied (all males); Group 1 comprised of non-diabetic subjects without CAD (n=50). Non-diabetic subjects with CAD formed group 2 (n=50); group 3 comprised of type 2 diabetic patients without CAD (n=50) and group 4 consisted of type 2 diabetic patients with CAD (n=50). CAD was diagnosed based on coronary angiographic evidence of severe double or triple vessel disease. RESULTS: Both diabetic and non-diabetic patients with CAD had significantly higher levels of tPA, PAI-1 and fibrinogen compared to non-diabetic without CAD (p < 0.05). Patients with CAD were distributed more in the upper tertiles of these risk factors compared to those without CAD. A strong association between tPA and PAI-1 was noted in the Pearson's correlation analysis (p < 0.001). Univariate regression analysis showed tPA (Odds ratio--1.12, p = 0.03), PAI-1 (Odds ratio--1.03, p = 0.008), fibrinogen (Odds ratio--1.01, p < 0.0001), serum cholesterol (Odds ratio--1.008, p = 0.04) and hypertension (Odds ratio--3.7, p = 0.0001) to be associated with CAD. Multiple logistic regression analysis revealed hypertension (Odds ratio--4.6, 95% confidence interval--2.113-9.950, p = 0.0001) and fibrinogen (Odds ratio--1.012, 95% confidence interval--1.007-1.018, p = 0.0001) as risk factors for CAD. CONCLUSION: Our study suggests that prothrombogenic risk factors particularly fibrinogen may be associated with CAD in South Indians.

Deepa R; Velmurugan K; Saravanan G; Dwarakanath V; Agarwal S; Mohan V

2002-07-01

107

Association of plasminogen activator inhibitor-1 and tissue plasminogen activator with type 2 diabetes and metabolic syndrome in Malaysian subjects  

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Full Text Available Abstract Background Increased plasma plasminogen activator inhibitor-1 (PAI-1) activity and decreased tissue plasminogen activator (tPA) activity could be considered a true component of the metabolic syndrome (MetS) associated with an increased risk of developing cardiovascular diseases (CVD) and fibrinolytic abnormalities. The aim of this study was to investigate the association of tPA and its inhibitor PAI-1 with type 2 diabetes (T2D) and MetS and interrelationship between PAI-1and tPA activities and antigens in Malaysian T2D and normal subjects. Methods The plasma activities and antigens of PAI-1 and tPA and the levels of the tPA/PAI-1 complex as well as serum insulin, parameter of the coronary risk panel and plasma glucose at fasting state were studied in 303 T2D subjects (227 with MetS and 76 without MetS), 131 normal non-diabetic non-metabolic subjects and 101 non-diabetic MetS subjects. Results The PAI-1 activity was higher in subjects with T2D with MetS (P = 9.8 × 10-19) and non-diabetic subjects with MetS (P = 3.0 × 10-15), whereas the tPA activity was lower in T2D with MetS (P = 0.003) as compare to normal subjects. Plasma tPA antigen levels were higher in subjects with T2D with MetS (P = 8.9 × 10-24), T2D without MetS (P = 1.3 × 10-13) and non-diabetic MetS subjects (P = 0.002). The activity and antigen of PAI-1 in normal subjects were related to insulin resistance (P = 2.2 × 10-4; 0.007). Additionally, the PAI-1 activity was associated with an increased waist circumference (P = 2.2 × 10-4) and decreased HDL-c (P = 0.005), whereas the tPA activity was associated with decreased FBG (P = 0.028). The highest correlation was between PAI-1 activity and its antigen (R2 = 0.695, P = 1.1 × 10-36) in diabetic subjects. The tPA activity negatively correlated with its antigen (R2 = -0.444, P = 7.7 × 10-13) in normal subjects and with the PAI-1 activity and antigen (R2 = -0.319, P = 9.9 × 10-12; R2 = -0.228, P = 3.4 × 10-6) in diabetic subjects. Conclusions PAI-1 and tPA activities and antigens were associated with diabetes and MetS parameters in Malaysian subjects.

Al-Hamodi Zaid; Ismail Ikram S; Saif-Ali Riyadh; Ahmed Khaled A; Muniandy Sekaran

2011-01-01

108

Plasminogen activator inhibitor-1 in the evolution of stroke  

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Full Text Available Fibrinolytic activity in the acute stroke was examined by monitoring the level of plasminogen activator inhibitor-1 (PAI-1), as one of the indicators of fibrinolytic activity. Given the role of PAI-1 in the processes of atherogenesis and thrombogenesis, plasma PAI-1 level was measured in 59 patients (up to 50 years of age) with atherothrombotic stroke (verified by computed tomography scanning or magnetic resonance imaging of brain) in the period from 12 to 24 hours (I analysis) and 30 days after the onset of stroke (II analysis); then, it was correlated with plasma PAI-1 level in the control group (57 healthy subjects), which was 2.86±0.70 U/ml. It was found that PAI-1 level was significantly higher in the acute stroke (I analysis: PAI-1 =4.10±1.40 U/ml, p0.05), as well as between females and males (p>0.05). Along with significantly increased fibrinogen level (4.65±1 g/l, in the controls - 2.83±0.64 g/l, p<0.001), significantly higher triglycerides (2.04±0.76 mmol/l, in the controls - 1.38+0.54 mmol/l, p<0.001) and lipoproteins(a) (0.405±0.29 g/l, in the controls -0.172±0.14 g/l, p<0.001) were found, correlating with higher plasma PAI-1 level in these patients. The increased plasma level of PAI-1 pointed to possibility of decreased fibrinolytic activity in pathogenesis of ischemie stroke, as well as, risk of reinsult, which had been the greatest after the onset of stroke and declined gradually within several weeks.

Jovanovi? Zagorka B.; Ili? Mirka; Zidverc-Trajkovi? Jasna; Pavlovi? Aleksandra M.; Mijajlovi? Milija; Šterni?-?ovi?kovi? Nadežda; Stankovi? Sanja; Besla?-Bumbaširevi? Ljiljana G.; Kosti? Vladimir S.

2004-01-01

109

A comparative study of amyloid-beta (1-42) as a cofactor for plasminogen activation by vampire bat plasminogen activator and recombinant human tissue-type plasminogen activator.  

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The activity of both human tissue-type plasminogen activator (t-PA) and the PA from the saliva of the vampire bat, Desmodus rotundus, (DSPA) is critically dependent on the presence of a cofactor. The most efficient cofactor for both PAs is fibrin, but fibrinogen and amyloid beta peptides also have cofactor activities for human t-PA. Compared to t-PA, DSPA has a more stringent requirement for fibrin as a cofactor. The present study was undertaken to compare cofactor activities of amyloid beta 1-42 (Abeta1-42) for plasminogen activation by DSPA-alpha1 or by t-PA. The two PAs were incubated with different concentrations of glu-plasminogen, a chromogenic substrate for plasmin and 100 micro g mL (-1) of Abeta1-42, fibrinogen or fibrin as cofactor. Using the kinetic parameters directly determined from the chromogenic substrate conversion curves, we derived the relative efficacies of DSPA or t-PA in the presence of cofactor at the physiological plasminogen concentration of 2 micro M. In the presence of fibrin, the activity of DSPA was comparable to that of t-PA and 23,270-fold higher than its activity without cofactor, whereas fibrin induced only a 248-fold increase in t-PA activity. The activity of DSPA with Abeta1-42 or fibrinogen as cofactor was 485-fold lower than its activity in the presence of fibrin, while for t-PA this difference was only 26-fold. The much lower activity of DSPA as compared to t-PA with Abeta1-42 or fibrinogen might lead to fewer side effects when used for the thrombolytic therapy of stroke. PMID:15351852

Kruithof, Egbert K O; Schleuning, Wolf-Dieter

2004-09-01

110

Tissue-type plasminogen activator gene targets thrombolysis in atriums.  

UK PubMed Central (United Kingdom)

Our previous investigations showed that retroviral gene transfer of tissue-type plasminogen activator (tPA) effectively targeted thrombolysis in vitro and in the model of inferior caval veins of rabbits. This study is to identify the target thrombolysis of retroviral vector recombinant pLEGFP-N1-tPA transferred into the tissue around the Dacron patch (the same materials making of the ring of mechanical valve) in left atriums of rabbits. 70 Dacron patches were transplanted into the left atriums of 70 New Zealand white rabbits. The rabbits were randomly divided into three groups according to the different handling methods, including local pLEGFP-N1-tPA transferred group (gene therapy group, 30 animals), pLEGFP-N1 transferred group (control group, 20 animals), medium DMEM + 10% neonate calf serum (NCS) injected group (blank control group, 20 animals). Samples of blood, Dacron pieces and left atriums (auricles) wall from half of above in each group were harvested on second day and another half were harvested on 75th day after surgery. The EGFP expression of harvested left atriums (auricles) wall were observed under the confocal. The thrombi on the surface of Dacron patches were detected by stereoscope and electron microscope. The tPA expression in left atriums (auricles) wall and in blood from left atriums were detected by Western blot and their thrombolysis and activities were observed and calculated in plasma plates. ELISA were used to identify the contents of tPA. No thrombus was seen on the surface of Dacron patches that were transplanted in left atriums by tPA locally transferring around them. Activity and content of tPA were high in local tissue of left atrium and in blood of left atrium. It demonstrated effectively thrombolysis by tPA rapidly, efficiently and long expressing. This puts the foundation of mechanical valve replacement model for tPA gene valve, next.

Gong Y; Wang F; Li X; Gao Z; Zhang K; Fan C; Liu X

2010-11-01

111

Tissue-type plasminogen activator gene targets thrombolysis in atriums.  

Science.gov (United States)

Our previous investigations showed that retroviral gene transfer of tissue-type plasminogen activator (tPA) effectively targeted thrombolysis in vitro and in the model of inferior caval veins of rabbits. This study is to identify the target thrombolysis of retroviral vector recombinant pLEGFP-N1-tPA transferred into the tissue around the Dacron patch (the same materials making of the ring of mechanical valve) in left atriums of rabbits. 70 Dacron patches were transplanted into the left atriums of 70 New Zealand white rabbits. The rabbits were randomly divided into three groups according to the different handling methods, including local pLEGFP-N1-tPA transferred group (gene therapy group, 30 animals), pLEGFP-N1 transferred group (control group, 20 animals), medium DMEM + 10% neonate calf serum (NCS) injected group (blank control group, 20 animals). Samples of blood, Dacron pieces and left atriums (auricles) wall from half of above in each group were harvested on second day and another half were harvested on 75th day after surgery. The EGFP expression of harvested left atriums (auricles) wall were observed under the confocal. The thrombi on the surface of Dacron patches were detected by stereoscope and electron microscope. The tPA expression in left atriums (auricles) wall and in blood from left atriums were detected by Western blot and their thrombolysis and activities were observed and calculated in plasma plates. ELISA were used to identify the contents of tPA. No thrombus was seen on the surface of Dacron patches that were transplanted in left atriums by tPA locally transferring around them. Activity and content of tPA were high in local tissue of left atrium and in blood of left atrium. It demonstrated effectively thrombolysis by tPA rapidly, efficiently and long expressing. This puts the foundation of mechanical valve replacement model for tPA gene valve, next. PMID:20924774

Gong, Yongsheng; Wang, Fajiu; Li, Xia; Gao, Zhixin; Zhang, Kailun; Fan, Chen; Liu, Xingen

2010-11-01

112

Immunological analysis of plasminogen activators from normal and transformed hamster cells. Evidence that the plasminogen activators produced by SV40 virus-transformed hamster embryo cells and normal hamster lung cells are antigenically identical  

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Rabbits were immunized against the plasminogen activator released by SV4- virus-transformed hamster embryo cells. The resulting antiplasminogen activator immunoglobulin (APA-IgG) inhibited the enzymatic activity of the plasminogen activator produced by SV40- transformed hamster cells, and the plasm...

113

Prognostic significance of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 in primary breast cancer.  

UK PubMed Central (United Kingdom)

The uPA-mediated pathway of plasminogen activation is central to cancer metastasis. Whether uPA and PAI-1 are related to local recurrence, metastatic spread or both is not clear. We present a retrospective study of 429 primary breast cancer patients with a median follow-up of 5.1 years, in which the levels of uPA and PAI-1 in tumour extracts were analysed by means of an enzyme-linked immunosorbent assay. The median values of uPA and PAI-1, which were used as cut-off points, were 4.5 and 11.1 ng mg(-1) protein respectively. The levels of uPA and PAI-1 were correlated with tumour size, degree of anaplasia, steroid receptor status and number of positive nodes. Patients with high content of either uPA or PAI-1 had increased risk of relapse and death. We demonstrated an independent ability of PAI-1 to predict distant metastasis (relative risk 1.7, confidence limits 1.22 and 2.46) and that neither uPA nor PAI-1 provided any information regarding local recurrence.

Knoop A; Andreasen PA; Andersen JA; Hansen S; Laenkholm AV; Simonsen AC; Andersen J; Overgaard J; Rose C

1998-03-01

114

Tissue plasminogen activator does not alter development of acquired epilepsy.  

UK PubMed Central (United Kingdom)

PURPOSE: ? Tissue plasminogen activator (t-PA), a proven therapy for acute ischemic stroke, is an endogenous serine protease associated with neuronal activity and synaptic plasticity in the brain. Its expression is enhanced after seizures, and is involved in seizure propagation throughout the brain. Therefore, the increased use of t-PA to treat stroke may have important implications for the development of poststroke epilepsy. Using experimental and clinical approaches, we investigated the role of t-PA in the development of epilepsy. METHODS: ? Mice deficient in t-PA (t-PA(-/-) ) or mice transgenically modified to overexpress neuronal t-PA (T4) underwent amygdala kindling, and seizure threshold and rates of kindling were compared to those in wild-type mice. For the clinical study, we recruited acute ischemic stroke patients who either received intravenous t-PA treatment on admission to hospital (n?=?177; cases) or did not (n?=?158; controls). We then assessed the incidence of early and late onset seizures and epilepsy in these patients. KEY FINDINGS: ? T4 mice were more seizure-prone than wild-type mice, exhibiting lower seizure thresholds (p?=?0.002), but there were no significant differences observed in the rate of kindling development when comparing either T4 mice, or t-PA(-/-) mice, to their wild-type controls. Furthermore, we found no significant differences between the proportion of poststroke patients experiencing early or late seizures, or developing epilepsy, between those who received t-PA and those who did not. SIGNIFICANCE: ? Overexpression of endogenous t-PA lowers seizure threshold but does not influence kindling epileptogenesis. Moreover, the therapeutic administration of t-PA in humans does not influence the development of acquired poststroke epilepsy.

Tan ML; Ng A; Pandher PS; Sashindranath M; Hamilton JA; Davis SM; O'Brien TJ; Medcalf RL; Yan B; Jones NC

2012-11-01

115

On the mechanism of fibrin-specific plasminogen activation by staphylokinase.  

UK PubMed Central (United Kingdom)

The mechanism of plasminogen activation by recombinant staphylokinase was studied both in the absence and in the presence of fibrin, in purified systems, and in human plasma. Staphylokinase, like streptokinase, forms a stoichiometric complex with plasminogen that activates plasminogen following Michaelis-Menten kinetics with Km = 7.0 microM and k2 = 1.5 s-1. In purified systems, alpha 2-antiplasmin inhibits the plasminogen-staphylokinase complex with k1(app) = 2.7 +/- 0.30 x 10(6) M-1 s-1 (mean +/- S.D., n = 12), but not the plasminogen-streptokinase complex. Addition of 6-aminohexanoic acid induces a concentration-dependent reduction of k1(app) to 2.0 +/- 0.17 x 10(4) M-1 s-1 (mean +/- S.D., n = 5) at concentrations greater than or equal to 30 mM, with a 50% reduction at a 6-aminohexanoic acid concentration of 60 microM. Staphylokinase does not bind to fibrin, and fibrin stimulates the initial rate of plasminogen activation by staphylokinase only 4-fold. Staphylokinase induces a dose-dependent lysis of a 0.12-ml 125I-fibrin-labeled human plasma clot submersed in 0.5 ml of citrated human plasma; 50% lysis in 2 h is obtained with 17 nM staphylokinase and is associated with only 5% plasma fibrinogen degradation. Corresponding values for streptokinase are 68 nM and more than 90% fibrinogen degradation. In the absence of a fibrin clot, 50% fibrinogen degradation in human plasma in 2 h requires 790 nM staphylokinase, but only 4.4 nM streptokinase. These results suggest the following mechanism for relatively fibrin-specific clot lysis with staphylokinase in a plasma milieu. In plasma in the absence of fibrin, the plasminogen-staphylokinase complex is rapidly neutralized by alpha 2-antiplasmin, thus preventing systemic plasminogen activation. In the presence of fibrin, the lysine-binding sites of the plasminogen-staphylokinase complex are occupied and inhibition by alpha 2-antiplasmin is retarded, thus allowing preferential plasminogen activation at the fibrin surface.

Lijnen HR; Van Hoef B; De Cock F; Okada K; Ueshima S; Matsuo O; Collen D

1991-06-01

116

Synthesis and properties of cyclic peptides containing the activation site of plasminogen  

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The activation of plasminogen results from proteolytic cleavage of the Arg/sub 560/-Val/sub 561/ bond by plasminogen activators. This region of the zymogen occurs in a small disulfide loop that must restrict the conformation around this bond. The nonapeptide sequence NH/sub 2/-Cys-Pro-Gly-Arg-Val-Val-Gly-Gly-Cys-NH/sub 2/ of plasminogen containing the activator sensitive arginyl valine bond was synthesized by carbodiimide coupling of Boc-Cys-Pro-Gly-OH(S-4-methylbenzyl) to NH/sub 2/-Arg(NO/sub 2/)-Val-Val-Gly-Gly-Cys-NH/sub 2/ (S-4-methylbenzyl), followed by HF treatment and K/sub 3/Fe(CN)/sub 6/ oxidation to form a disulfide bond. Purified peptide was not a substract for urokinase (UK) or plasminogen activator (PA) but possessed a slightly inhibitory activity towards PA. Addition of a lysine to the N-terminus of the nonapeptide yielded a decapeptide sequence of plasminogen that was a better substrate for UK but not for PA. The decapeptide inhibits PA slightly but not UK. These results suggest that active site geometry for PA must be more restrictive than that of UK and that other regions may be involved in the productive interactions with the activators inducing a better fit of the cyclic peptide loop.

Ganu, V.S.; Shaw, E.

1982-01-01

117

Activity and expression of urokinase-type plasminogen activator and matrix metalloproteinases in human colorectal cancer  

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Full Text Available Abstract Background Matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-type plasminogen activator (uPA) are involved in colorectal cancer invasion and metastasis. There is still debate whether the activity of MMP-2 and MMP-9 differs between tumors located in the colon and rectum. We designed this study to determine any differences in the expression of MMP-2, MMP-9 and uPA system between colon and rectal cancer tissues. Methods Cancer tissue samples were obtained from colon carcinoma (n = 12) and rectal carcinomas (n = 10). MMP-2 and MMP-9 levels were examined using gelatin zymography and Western blotting; their endogenous inhibitors, tissue inhibitor of metalloproteinase-2 (TIMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1), were assessed by Western blotting. uPA, uPAR and PAI-1 were examined using enzyme-linked immunosorbent assay (ELISA). The activity of uPA was assessed by casein-plasminogen zymography. Results In both colon and rectal tumors, MMP-2, MMP-9 and TIMP-1 protein levels were higher than in corresponding paired normal mucosa, while TIMP-2 level in tumors was significantly lower than in normal mucosa. The enzyme activities or protein levels of MMP-2, MMP-9 and their endogenous inhibitors did not reach a statistically significant difference between colon and rectal cancer compared with their normal mucosa. In rectal tumors, there was an increased activity of uPA compared with the activity in colon tumors (P = 0.0266), however urokinase-type plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) showed no significant difference between colon and rectal cancer tissues. Conclusion These findings suggest that uPA may be expressed differentially in colon and rectal cancers, however, the activities or protein levels of MMP-2, MMP-9, TIMP-1, TIMP-2, PAI-1 and uPAR are not affected by tumor location in the colon or the rectum.

Kim Tae-Dong; Song Kyoung-Sub; Li Ge; Choi Hoon; Park Hae-Duck; Lim Kyu; Hwang Byung-Doo; Yoon Wan-Hee

2006-01-01

118

Plasminogen activator activity during growth and differentiation of human HL-60 promyelocytes  

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The involvement of plasminogen activators (PA) of urokinase or tissue type which activate plasminogen to plasmin have been implicated in fibrinolysis, differentiation and cancer growth. In the present study, alteration of PA activity of human HL-60 promyelocytes during growth and differentiation has been investigated. HL-60 promyelocytes seeded at a density of 1 x 10/sup 5/ cells/ml, were examined at different densities of growth (0.2-2.0 x 10/sup 6/ cells/ml for PA activity, measured as plasminogen dependent hydrolysis of /sup 125/I labelled fibrin or D-Val-L-Leu-L-Lys-pNA. /sup 125/I-fibrin is hydrolyzed at a linear rate between 2-6 hours and at cell concentration of .2-1 x 10/sup 6/ per ml. The cellular PA activity per 10/sup 6/ cells at different growth densities decreases by 50% between .2-2 x 10/sup 6/ cells/ml. Similarly, when cells are differentiated to monocytes-macrophages by 1,25-dihydroxyvitamin D/sub 3/ (as determined by NBT reduction), a decrease in PA activity is observed which parallels the degree of differentiation. The major alteration of PA activity is in the heavy membrane fraction of the differentiated cells. These studies suggest that PA levels may be important in the growth and differentiation of HL-60 cells.

Kumar, S.; Russo, M.S.

1986-05-01

119

Recombinant tissue plasminogen activator in the treatment of suprachoroidal hemorrhage  

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Full Text Available Nancy Kunjukunju1, Christine R Gonzales2, William S Rodden21Ochsner Medical Center, New Orleans, Louisiana; 2Retina and Vitreous Center of Southern Oregon, Ashland, Oregon, USABackground: Suprachoroidal hemorrhages are a vision-threatening complication, and poor visual outcome is correlated with increasing hemorrhage complexity. The recommended time of surgical drainage is 10–14 days after the hemorrhage begins to liquefy. We describe a case in which recombinant tissue plasminogen activator (r-tPA), alteplase, is injected within the suprachoroidal space before surgery to assist in the drainage of an organized clot prior to liquefaction. This is a report of a technique in which r-tPA is used in the intrachoroidal space to target the organized clot of suprachoroidal hemorrhage prior to drainage.Case report: A 62-year-old male presented 12 days after retinal detachment repair with sudden ocular pain and vision loss after a Valsalva maneuver. Vision was light perception only, and intraocular pressure was 43 mmHg. Diagnosed with hyphema and suprachoroidal hemorrhage, the patient underwent surgery the following day. An injection of r-tPA 100 µg was given intracamerally, and an additional dose of r-tPA 100 µg was injected into the suprachoroidal space prior to surgery. Liquified by r-tPA, the clot was expressed through the sclerotomies. Best corrected vision in the eye eight months after the drainage procedure was 20/40.Conclusion: To the author’s knowledge, this is the first reported case in which r-tPA was successfully injected in the suprachoroidal space to liquefy and drain a suprachoroidal hemorrhage prior to natural dissolution.Keywords: tPA, suprachoroidal hemorrhage, vision loss

Nancy Kunjukunju; Christine R Gonzales; William S Rodden

2011-01-01

120

Complexes between tissue-type plasminogen activator and proteinase inhibitors in human plasma, identified with an immunoradiometric assay  

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Extrinsic (tissue-type) plasminogen activator antigen in human plasma, as measured by a two-site immunoradiometric assay, is composed of a fibrin-adsorbable and a nonadsorbable fraction. Gel filtration on Ultrogel AcA 44 in 1.6M KSCN of the fibrin-adsorbable fraction showed a peak with M/sub r/ approx. =70,000, which contained plasminogen activator activity and was assumed to represent free extrinsic plasminogen activator. The nonadsorbable fraction showed a broad peak with M/sub r/ approx. =140,000 without plasminogen activator activity. Overnight incubation at 370C of postexercise plasma revealed a shift of the M/sub r/ approx. =70,000 peak to the M/sub r/ approx. =140,000 position, suggesting that the M/sub r/ approx. =140,000 peak consists of extrinsic plasminogen activator-protease inhibitor complex(es). ?2-Antiplasmin is the main inhibitor of extrinsic plasminogen activator in plasma and is probably responsible for the generation of the M/sub r/ approx. =140,000 component. A possible involvement of other plasma proteinase inhibitors was explored by incubation of 125I-labeled extrinsic plasminogen activator in ?2-antiplasmin-depleted plasma. A complex was formed with a t1/2 of about 1 hr, which was identified by immunoprecipitation as extrinsic plasminogen activator-?2-antiplasmin complex. Additional evidence for the presence of extrinsic plasminogen activator complexes with ?2-antiplasmin and ?1-antitrypsin in plasma was obtained from two-site immunoradiometric assays. It was concluded that plasma contains both free extrinsic plasminogen activator and plasminogen activator complexes with ?2-antiplasmin and ?1-antitrypsin. These complexes are also present in plasma collected on the active site inhibitor, D-Phe-Pro-Arg-CH2Cl, at rest and after exercise and are therefore assumed to circulate in vivo.

1983-01-01

 
 
 
 
121

Plasminogen activator inhibitor-1 (PAI-1) and urokinase plasminogen activator (uPA) in sputum of allergic asthma patients.  

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Full Text Available Urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) have been associated with asthma. The aim of this study was to evaluate concentration of uPA and PAI-1 in induced sputum of house dust mite allergic asthmatics (HDM-AAs). The study was performed on 19 HDM-AAs and 8 healthy nonatopic controls (HCs). Concentration of uPA and PAI-1 was evaluated in induced sputum supernatants using ELISA method. In HDM-AAs the median sputum concentration of uPA (128 pg/ml; 95% CI 99 to 183 pg/ml) and PAI-1 (4063 pg/ml; 95%CI 3319 to 4784 pg/ml) were significantly greater than in HCs (17 pg/ml; 95%CI 12 to 32 pg/ml; p<0.001 and 626 pg/ml; 95%CI 357 to 961 pg/ml; p<0.001 for uPA and PAI-1 respectively). The sputum concentration of uPA correlated with sputum total cell count (r=0.781; p=0.0001) and with logarithmically transformed exhaled nitric oxide concentration (eNO) (r=0.486; p=0.035) but not with FEV1 or bronchial reactivity to histamine. On the contrary, the sputum PAI-1 concentration correlated with FEV1 (r=-0,718; p=0.0005) and bronchial reactivity to histamine expressed as log(PC20) (r=-0.824; p<0.0001) but did not correlate with sputum total cell count or eNO. The results of this study support previous observations linking PAI-1 with airway remodeling and uPA with cellular inflammation. Moreover, the observed effect of uPA seems to be independent of its fibrynolytic activity.

Krzysztof Kowal; Sebastian Zukowski; Marcin Moniuszko; Anna Bodzenta-?ukaszyk

2008-01-01

122

The construction and expression of chimeric urokinase-type plasminogen activator genes containing kringle domains of human plasminogen.  

UK PubMed Central (United Kingdom)

A series of chimeric urokinase-type plasminogen activator (uPA) genes, which contain combinations of kringle domains of human plasminogen (HPg) in place of the uPA kringle (KuPA), has been constructed and expressed. Some of the resulting recombinant (r) variant uPA chimeras contain modules that potentially mediate the macroscopic binding of HPg to its activation effectors, fibrin(ogen) and 6-aminohexanoic acid (EACA). Such binding sites are not possessed by KuPA, but are present in certain of the HPg kringles, viz., kringle 1 (K1HPg), kringle 4 (K4HPg), and kringle 5 (K5HPg). The recombinant (r) chimeras constructed included molecules with replacements of KuPA with K1HPg (r-[KuPA-->K1HPg]uPA), and with KuPA replaced by double kringle combinations of K1HPgK4HPg (r-[KuPA-->K1HPgK4HPg]uPA), K2HPgK3HPg (r-[KuPA-->K2HPgK3HPg]uPA), and K4HPgK5HPg (r-[KuPA-->K4HPgK5HPg]uPA). All of these variant genes, along with their wild-type (wt) r-uPA counterparts, were expressed in human kidney 293 cells. In cases wherein EACA-binding kringles from HPg have been placed in uPA, this property has been retained in the chimeric molecule and employed as an essential part of the purification procedures for the variants. The steady state amidolytic activity of two-chain (tc) wtr-uPA toward the chromogenic substrate, H-D-pyroglutamyl-Gly-L-Arg-p-nitroanilide (S2444), is characterized by a kcat/KM (pH 7.4, 37 degrees C) of 120 s-1 mM-1. This value ranges from 92 s-1 mM-1 (tcr-[KuPA-->K1HPg]uPA) to 166 s-1 mM-1 (tcr-[KuPA-->K1HPgK4HPg]uPA) for each of the variants, demonstrating that the catalytic efficiency of the active site is altered only in a small way by changes in the noncatalytic domain of uPA. Small differences are also observed in the abilities of these tcr variants to interact with the fast-acting plasma inhibitor of uPA, viz., plasminogen activator inhibitor-1 (PAI-1). The second-order rate constant for the interaction of PAI-1 with tcr-uPA, 0.46 x 10(7) M-1s-1 (pH 7.4, 10 degrees C), ranges from 0.29 x 10(7) M-1s-1 (tcr-[KuPA-->K1HPgK4HPg]uPA) to 1.08 x 10(7) M-1s-1 (tcr-[KuPA-->K4HPgK5HPg]uPA), for the tcr-chimeric variants. Neither wtr-uPA nor any of its chimeric r-variants interacted macroscopically with a fibrin clot under conditions that allowed binding of 74% of single-chain r-tissue-type plasminogen activator. However, the tcr-chimeric uPA variants provided HPg-enriched clot lysis times between 0.2 (r-[KuPA-->K1HPgK4HPg]uPA) and 2.4 (r-[KuPA-->K2HPgK3HPg]uPA) relative to that of wtr-uPA.(ABSTRACT TRUNCATED AT 400 WORDS)

Boutaud A; Castellino FJ

1993-06-01

123

The plasminogen activation system: new targets in lung inflammation and remodeling.  

UK PubMed Central (United Kingdom)

The plasminogen activation system (PAS) and the plasmin it forms have dual roles in chronic respiratory diseases including asthma, chronic obstructive pulmonary disease and interstitial lung disease. Whilst plasmin-mediated airspace fibrinolysis is beneficial, interstitial plasmin contributes to lung dysfunction because of its pro-inflammatory and tissue remodeling activities. Recent studies highlight the potential of fibrinolytic agents, including small molecule inhibitors of plasminogen activator inhibitor-1 (PAI-1), as treatments for chronic respiratory disease. Current data also suggest that interstitial urokinase plasminogen activator is an important mediator of lung inflammation and remodeling. However, further preclinical characterization of uPA as a drug target for lung disease is required. Here we review the concept of selectively targeting the contributions of PAS to treat chronic respiratory disease.

Schuliga M; Westall G; Xia Y; Stewart AG

2013-06-01

124

PHARMACEUTICAL PACKAGING UNIT CONTAINING PLASMINOGEN ACTIVATORS FOR MULTIPLE-BOLUS ADMINISTRATION  

UK PubMed Central (United Kingdom)

The subject matter of the present invention is a pharmaceutical packaging unit containing plasminogen activators for multiple-bolus administration. In particular, the invention concerns a pharmaceutical packaging unit for treating thromboembolic disorders. The packaging unit comprises essentially two components. The first component is an ordinary pharmaceutical administration form of a protein with a plasminogen-activator activity with a prolonged half-life with respect to t-PA. The second component consists of an instruction for application of this protein in the form of a fractionated administration in two or more bolus injections.

MARTIN Ulrich; KOENIG Reinhard

125

Three decades of research on plasminogen activator inhibitor-1: a multifaceted serpin.  

UK PubMed Central (United Kingdom)

Plasminogen activator inhibitor 1 (PAI-1) is the main inhibitor of tissue-type (t-PA) and urokinase-type (u-PA) plasminogen activator and therefore plays an important role in the plasminogen-plasmin system. PAI-1 is involved in a variety of cardiovascular diseases (mainly through inhibition of t-PA) as well as in cell migration and tumor development (mainly through inhibition of u-PA and interaction with vitronectin). PAI-1 is a unique member of the serpin superfamily, exhibiting particular unique conformational and functional properties. Because of its involvement in various biologic and pathophysiologic processes, PAI-1 has been the subject of many studies, including extensive structural investigations, in vitro cell biologic studies, in vivo animal studies, and epidemiologic studies. The review provides an overview on the current knowledge on PAI-1.

Declerck PJ; Gils A

2013-06-01

126

Catalytic domain structure of vampire bat plasminogen activator: a molecular paradigm for proteolysis without activation cleavage.  

Science.gov (United States)

The saliva of the blood-eating vampire bat Desmodus rotundus contains plasminogen activators (PAs) that maintain the fluidity of the prey's blood by activating plasminogen and dissolving developing fibrin clots. D. rotundus salivary PAs (DSPAs) are composed of evolutionarily conserved domains reminiscent of human tissue-type PA (tPA), but their catalytic domain lacks a plasmin-sensitive "activation cleavage site". Despite this, all DSPAs are intrinsically active and enormously stimulated in the presence of fibrin. The recombinant catalytic domain of DSPAalpha1 has been crystallized in a covalent complex with Glu-Gly-Arg-chloromethyl ketone and its structure solved at 2.9 A resolution. The structure is similar to that of activated two-chain human tPA. Despite its single-chain status, the activation domain is observed in an enzymatically active conformation, with a functional substrate binding site and active site accommodating the peptidylmethylene inhibitor. The activation pocket, which normally receives the N-terminal Ile16, is occupied by the side chain of Lys156, whose distal ammonium group makes an internal salt bridge with the carboxylate group of Asp194. Lys156 is in a groove shielded from the bulk solvent by the intact "activation loop" (Gln10-Phe21), favoring Lys156-Asp194 salt bridge formation and stabilization of a functional substrate binding site. Together with the characteristic 186 insertion loop, the activation loop could act as a switch, effecting full single-chain enzymatic activity upon binding to fibrin. PMID:9354616

Renatus, M; Stubbs, M T; Huber, R; Bringmann, P; Donner, P; Schleuning, W D; Bode, W

1997-11-01

127

Plasminogen activator inhibitor type 1 regulates microglial motility and phagocytic activity  

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Full Text Available Abstract Background Plasminogen activator inhibitor type 1 (PAI-1) is the primary inhibitor of urokinase type plasminogen activators (uPA) and tissue type plasminogen activators (tPA), which mediate fibrinolysis. PAI-1 is also involved in the innate immunity by regulating cell migration and phagocytosis. However, little is known about the role of PAI-1 in the central nervous system. Methods In this study, we identified PAI-1 in the culture medium of mouse mixed glial cells by liquid chromatography and tandem mass spectrometry. Secretion of PAI-1 from glial cultures was detected by ELISA and western blotting analysis. Cell migration was evaluated by in vitro scratch-wound healing assay or Boyden chamber assay and an in vivo stab wound injury model. Phagocytic activity was measured by uptake of zymosan particles. Results The levels of PAI-1 mRNA and protein expression were increased by lipopolysaccharide and interferon-? stimulation in both microglia and astrocytes. PAI-1 promoted the migration of microglial cells in culture via the low-density lipoprotein receptor-related protein (LRP) 1/Janus kinase (JAK)/signal transducer and activator of transcription (STAT)1 axis. PAI-1 also increased microglial migration in vivo when injected into mouse brain. PAI-1-mediated microglial migration was independent of protease inhibition, because an R346A mutant of PAI-1 with impaired PA inhibitory activity also promoted microglial migration. Moreover, PAI-1 was able to modulate microglial phagocytic activity. PAI-1 inhibited microglial engulfment of zymosan particles in a vitronectin- and Toll-like receptor 2/6-dependent manner. Conclusion Our results indicate that glia-derived PAI-1 may regulate microglial migration and phagocytosis in an autocrine or paracrine manner. This may have important implications in the regulation of brain microglial activities in health and disease.

Jeon Hyejin; Kim Jong-Heon; Kim Jae-Hong; Lee Won-Ha; Lee Myung-Shik; Suk Kyoungho

2012-01-01

128

t-plasminogen activator inhibitor-1 polymorphism in idiopathic pulmonary arterial hypertension  

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Full Text Available Aim: The aim of the present study was to identify the possible genotypic association of 3?UTR Hind III polymorphism of Plasminogen activator Inhibitor-1 (PAI-1) gene with idiopathic pulmonary arterial hypertension (IPAH). Background: IPAH is a disorder with abnormally raised mean pulmonary arterial pressure and increase in the resistance to blood flow in pulmonary artery. One of the pathological features seen is development of intraluminal thrombin deposition leading to thrombosis. Plasminogen activator inhibitor-1 is an important inhibitor of the fibrinolytic system; its up-regulation may suppress fibrinolysis and result in an increased risk of thrombosis. Method: Blood samples from 54 IPAH patients and 100 healthy voluntary donors were analyzed by PCR-RFLP method for 3?UTR Hind III polymorphism. Results and Disscussion: A significant association of Hd2 allele with the disease was observed. Raised mean level of right ventricular systolic pressure was observed in the Hd2/Hd2 genotypic patients, strengthening the role of Hd2 allele in the disease progression. Our data suggests an association of Hd2/Hd2 genotype, which may lead to the up-regulation of PAI-1 gene leading to increased levels of PAI-1, which is seen in IPAH. PAI-1 competes with plasminogen activators and hinders the normal mechanism of plasminogen activation system and leads to thrombosis and formation of plexiform lesions in the lung tissue, further strengthening its role in tissue remodeling and disease progression.

Katta Sujana; Vadapalli Shivani; Sastry BKS; Nallari Pratibha

2008-01-01

129

Regulation of Plasminogen Activator Inhibitor-1 Expression by Tumor Suppressor Protein p53*  

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H1299 lung carcinoma cells lacking p53 (p53-/-) express minimal amounts of plasminogen activator inhibitor-1 (PAI-1) protein as well as mRNA. p53-/- cells express highly unstable PAI-1 mRNA. Transfection of p53 in p53-/- cells enhanced PAI-1 expression and stabilized PAI-1 mRNA. On the contrary,...

Shetty, Sreerama; Shetty, Praveenkumar; Idell, Steven; Velusamy, Thirunavukkarasu; Bhandary, Yashodhar P.; Shetty, Rashmi S.

130

Expression of Plasminogen Activator Pla of Yersinia pestis Enhances Bacterial Attachment to the Mammalian Extracellular Matrix  

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The effect of the plasminogen activator Pla of Yersinia pestis on the adhesiveness of bacteria to the mammalian extracellular matrix was determined. Y. pestis KIM D27 harbors the 9.5-kb plasmid pPCP1, encoding Pla and pesticin; the strain efficiently adhered to the reconstituted basement membrane pr...

Lähteenmäki, Kaarina; Virkola, Ritva; Sarén, Anne; Emödy, Levente; Korhonen, Timo K.

131

Dexamethasone decreases urokinase plasminogen activator mRNA stability in MAT 13762 rat mammary carcinoma cells.  

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The glucocorticoid dexamethasone was observed to decrease urokinase plasminogen activator (uPA) RNA levels from within 1 h of treatment of MAT 13762 mammary adenocarcinoma cells. The drug did not alter the rate of uPA gene transcription in these cells, but decreased the stability of cytoplasmic uPA ...

Henderson, B. R.; Kefford, R. F.

132

Production of Plasminogen Activator in Cultures of Superior Cervical Ganglia and Isolated Schwann Cells  

Science.gov (United States)

Plasminogen activator has been implicated in tissue remodeling and cell migration during embryogenesis. In the developing nervous system, these processes are evident in the migration of neurons, axonal extension, Schwann cell migration, and the ensheathment and myelination of nerves. We have studied the production of plasminogen activator in cultures of superior cervical ganglia under conditions in which both neurons and glia are present. We have found that a principal source of the enzyme in these cultures is the glial cells and that the enzyme could not be detected at the growing tips of neurites. Plasminogen activator is also produced by Schwann cells isolated from neonatal rat sciatic nerve. The production of the enzyme by these cells is stimulated 6- to 10-fold by cholera toxin. Isolated Schwann cells and glial cells in the ganglion explant cultures produce the tissue form of plasminogen activator, a form of the enzyme not often found in nonmalignant cells. Preliminary experiments suggest that neuronal-glial interactions may regulate enzyme production by Schwann cells.

Alvarez-Buylla, Arturo; Valinsky, Jay E.

1985-05-01

133

NMR secondary structure of the plasminogen activator protein staphylokinase  

International Nuclear Information System (INIS)

Staphylokinase (Sak) is a 15.5 kDa protein secreted by several strains of Staphylococcusaureus. Due to its ability to convert plasminogen, the inactive proenzyme of the fibrinolytic system, into plasmin, Sak is presently undergoing clinical trials for blood clot lysis in the treatment of thrombovascular disorders. With a view to developing a better understanding of the mode of action of Sak, we have initiated a structural investigation of Sak via multidimensional heteronuclear NMR spectroscopy employing uniformly 15N- and 15N, 13C-labelled Sak. Sequence-specific resonance assignments have been made employing 15N-edited TOCSY and NOE experiments and from HNCACB, CBCA(CO)NH, HBHA(CBCACO)NH and CC(CO)NH sets of experiments. From an analysis of the chemical shifts, 3JHNH? scalar coupling constants, NOEs and HN exchange data, the secondary structural elements of Sak have been characterized

1997-01-01

134

NMR secondary structure of the plasminogen activator protein staphylokinase  

Energy Technology Data Exchange (ETDEWEB)

Staphylokinase (Sak) is a 15.5 kDa protein secreted by several strains of Staphylococcusaureus. Due to its ability to convert plasminogen, the inactive proenzyme of the fibrinolytic system, into plasmin, Sak is presently undergoing clinical trials for blood clot lysis in the treatment of thrombovascular disorders. With a view to developing a better understanding of the mode of action of Sak, we have initiated a structural investigation of Sak via multidimensional heteronuclear NMR spectroscopy employing uniformly 15N- and 15N, 13C-labelled Sak. Sequence-specific resonance assignments have been made employing 15N-edited TOCSY and NOE experiments and from HNCACB, CBCA(CO)NH, HBHA(CBCACO)NH and CC(CO)NH sets of experiments. From an analysis of the chemical shifts, 3JHNH{alpha} scalar coupling constants, NOEs and HN exchange data, the secondary structural elements of Sak have been characterized.

Ohlenschlaeger, O.; Ramachandran, R.; Flemming, J.; Guehrs, K.-H.; Schlott, B.; Brown, L.R. [Institute of Molecular Biotechnology, Department of Molecular Biophysics/NMR Spectroscopy (Germany)

1997-04-15

135

A study of the ability of tissue plasminogen activator to diffuse into the subretinal space after intravitreal injection in rabbits.  

UK PubMed Central (United Kingdom)

PURPOSE: Intravitreal injections of tissue plasminogen activator have been used to lyse fibrin from blood in the subretinal space, despite the lack of proof that tissue plasminogen activator can diffuse across the retina. We tested whether tissue plasminogen activator injected into the vitreous could penetrate the neural retina and enter the subretinal space. METHODS: We injected a mixture of 50 microg of tissue plasminogen activator (70 kD) labeled with fluorescein isothiocyanate and rhodamine B isothiocyanate-labeled dextran, which has a lower molecular weight (20 kD), into the midvitreous cavity of one eye in each of 18 rabbits. The eyes were enucleated after 3, 6, and 24 hours, and cryosections were examined with epifluorescent microscopy to determine the distribution of the labeled molecules. We also evaluated tissue plasminogen activator pharmacokinetics in one eye each of 18 rabbits in which a subretinal clot was induced by injecting autologous blood (50 microL) into the subretinal space through the sclera. Fluorescein isothiocyanate-labeled tissue plasminogen activator was injected into the vitreous 2 days after induction of the subretinal clot. RESULTS: Fluorescein isothiocyanate-labeled tissue plasminogen activator was present at the vitreal surface of the retina in a linear array in all 36 eyes studied, whereas the rhodamine B isothiocyanate-labeled dextran had diffused throughout the neural retina in the same sections. No fluorescein isothiocyanate signal was observed in the neural retina or in the subretinal clot. Vitreous hemorrhage caused by retinal perforation was observed in all eyes with intraretinal hemorrhage in which fluorescein isothiocyanate fluorescence was seen in the neural retina and inside the clot. CONCLUSION: Intravitreal tissue plasminogen activator did not diffuse through the intact neural retina to reach a subretinal clot. This study demonstrates no scientific rationale for the intravitreal tissue plasminogen activator treatment of submacular hemorrhage without vitreous hemorrhage presumably caused by an overlying retinal break.

Kamei M; Misono K; Lewis H

1999-12-01

136

Induction of macrophage plasminogen activator by asbestos is independent of PKC activation  

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This study was undertaken to assess whether plasminogen activator (PA) induction in macrophages exposed to chrysotile fibers is mediated by protein kinase C (PKC) activation. In PKC depleted J774 cells, PA induction could be elicited by chrysotile whereas, as expected, the response to phorbol myristate acetate (PMA) was abolished. The effect of PMA and chrysotile on the distribution of PKC activity in the J774 cell line was also compared by measuring the enzyme catalytic activity and phorbol dibutyrate (PDBu) binding sites. No redistribution of PKC was observed after simulation with PA inducing doses of chrysotile, whereas a clear translocation was observed with PMA. It is concluded that the mechanism of PA induction by chrysotile in this macrophage-like cell line is independent of PKC activation. (orig.).

Lison, D.; Raguzzi, F.; Lauwerys, R. (Louvain Univ., Brussels (Belgium). Industrial Toxicology and Occupational Medicine Unit)

1991-07-01

137

Plasminogen activator inhibitor-1, free fatty acids, and insulin resistance in patients with myocardial infarction  

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Full Text Available Olga Gruzdeva, Evgenya Uchasova, Yulia Dyleva, Ekaterina Belik, Ekaterina Shurygina, Olga Barbarash Research Institute for Complex Issues of Cardiovascular Diseases under the Siberian Branch of the Russian Academy of Medical Sciences, Kemerovo, Russian Federation Background: Insulin resistance is known to be a common feature of type 2 diabetes mellitus and is regarded as an important mechanism in the pathogenesis of this disease. The key pathogenetic mechanisms of insulin resistance progression are free fatty acids metabolism impairment and enhanced activity of plasminogen activator inhibitor 1. Both free fatty acids and plasminogen activator inhibitor 1 are recognized as risk factors for coronary heart disease. Methods: The patients were divided into two groups: group 1 included 65 non-diabetic myocardial infarction patients and group 2 enrolled 60 diabetic myocardial infarction patients. The control group consisted of 30 sex- and age-matched volunteers. The concentration of serum free fatty acids, glucose, C-peptide, and insulin were measured on the 1st and 12th days of the study. All the patients had their postprandial glycemia, insulin, and C-peptide concentrations measured 2 hours after a standard carbohydrate breakfast containing 360 kcal (protein 20 g, carbohydrate 57 g, and fat 9 g). Results: Free fatty acids levels in group 1 and in group 2 exceeded the control group values by 7-fold and 11-fold, respectively. Plasminogen activator inhibitor 1 concentration was 2.5-fold higher in group 1 and 4.6-fold higher in group 2 compared to the control group on the 1st day from the myocardial infarction onset. In addition, plasminogen activator inhibitor 1 concentration was significantly reduced in both groups on the 12th day from the myocardial infarction onset; however, it did not achieve the control group values. Conclusion: Increased postprandial glucose level, insulinemia, and elevated levels of free fatty acids and plasminogen activator inhibitor are associated with myocardial infarction-associated progression of insulin resistance. However, insulin resistance metabolic markers are of great predictive capacity in the assessment of risk of acute coronary events. Keywords: free fatty acids, type 2 diabetes mellitus, myocardial infarction, insulin resistance, plasminogen activator inhibitor 1

Gruzdeva O; Uchasova E; Dyleva Y; Belik E; Shurygina E; Barbarash O

2013-01-01

138

An enzyme-immunobinding assay for fast screening of expression of tissue plasminogen activator cDNA in E. coli  

International Nuclear Information System (INIS)

Tissue plasminogen activator (TPA) has been isolated from normal human tissues and certain human cell lines in culture. The enzyme is a serine protease which converts an inactive zymogen, plasminogen to plasmin, and causes lysis of fibrin clots. The high affinity of TPA for fibrin indicates that it is a potential thrombolytic agent and is superior to urokinase-like plasminogen activators. Recently, TPA has been cloned and expressed in E. coli. Using TPA as a model protein, the authors report here the development of a direct, sensitive enzyme-immunoassay for the screening of a cDNA expression library using specific antibodies and peroxidase-labeled second antibody.

1984-01-01

139

Secretion of extracellular hsp90? via exosomes increases cancer cell motility: a role for plasminogen activation  

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Full Text Available Abstract Background Metastasis is a multi-step process that is responsible for the majority of deaths in cancer patients. Current treatments are not effective in targeting metastasis. The molecular chaperone hsp90? is secreted from invasive cancer cells and activates MMP-2 to enhance invasiveness, required for the first step in metastasis. Methods We analyzed the morphology and motility of invasive cancer cells that were treated with exogenous exosomes in the presence or absence of hsp90?. We performed mass spectrometry and immunoprecipitation to identify plasminogen as a potential client protein of extracellular hsp90?. Plasmin activation assays and migration assays were performed to test if plasminogen is activated by extracellular hsp90? and has a role in migration. Results We found that hsp90? is secreted in exosomes in invasive cancer cells and it contributes to their invasive nature. We identified a novel interaction between hsp90? and tissue plasminogen activator that together with annexin II, also found in exosomes, activates plasmin. Extracellular hsp90? promotes plasmin activation as well as increases plasmin dependent cell motility. Conclusions Our data indicate that hsp90? is released by invasive cancer cells via exosomes and implicates hsp90? in activating plasmin, a second protease that acts in cancer cell invasion.

McCready Jessica; Sims Jessica D; Chan Doug; Jay Daniel G

2010-01-01

140

Complexes between tissue-type plasminogen activator and proteinase inhibitors in human plasma, identified with an immunoradiometric assay  

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Extrinsic (tissue-type) plasminogen activator antigen in human plasma, as measured by a two-site immunoradiometric assay, is composed of a fibrin-adsorbable and a nonadsorbable fraction. Gel filtration on Ultrogel AcA 44 in 1.6M KSCN of the fibrin-adsorbable fraction showed a peak with M/sub r/ approx. =70,000, which contained plasminogen activator activity and was assumed to represent free extrinsic plasminogen activator. The nonadsorbable fraction showed a broad peak with M/sub r/ approx. =140,000 without plasminogen activator activity. Overnight incubation at 37/sup 0/C of postexercise plasma revealed a shift of the M/sub r/ approx. =70,000 peak to the M/sub r/ approx. =140,000 position, suggesting that the M/sub r/ approx. =140,000 peak consists of extrinsic plasminogen activator-protease inhibitor complex(es). ..cap alpha../sub 2/-Antiplasmin is the main inhibitor of extrinsic plasminogen activator in plasma and is probably responsible for the generation of the M/sub r/ approx. =140,000 component. A possible involvement of other plasma proteinase inhibitors was explored by incubation of /sup 125/I-labeled extrinsic plasminogen activator in ..cap alpha../sub 2/-antiplasmin-depleted plasma. A complex was formed with a t1/2 of about 1 hr, which was identified by immunoprecipitation as extrinsic plasminogen activator-..cap alpha../sub 2/-antiplasmin complex. Additional evidence for the presence of extrinsic plasminogen activator complexes with ..cap alpha../sub 2/-antiplasmin and ..cap alpha../sub 1/-antitrypsin in plasma was obtained from two-site immunoradiometric assays. It was concluded that plasma contains both free extrinsic plasminogen activator and plasminogen activator complexes with ..cap alpha../sub 2/-antiplasmin and ..cap alpha../sub 1/-antitrypsin. These complexes are also present in plasma collected on the active site inhibitor, D-Phe-Pro-Arg-CH/sub 2/Cl, at rest and after exercise and are therefore assumed to circulate in vivo. (JMT)

Rijken, D.C. (Univ. of Leuven, Belgium); Juhan-Vague, I.; Collen, D.

1983-02-01

 
 
 
 
141

Effects of black cohosh on the plasminogen activator system in vascular smooth muscle cells.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The rhizome of the Cimicifuga racemosa plant (commonly known as black cohosh) has been used for menopausal complaints. Studies regarding the cardiovascular effects of black cohosh are lacking. We investigated the effect of black cohosh on the plasminogen activator system in cultured vascular smooth muscle cells (VSMCs). METHODS: VSMCs were isolated from rat aortae. Expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) proteins were evaluated by Western blot analysis and enzyme-linked immunosorbent assay, respectively. The activities of PAI-1 and t-PA in the conditioned media were assessed by fibrin overlay zymography. A 40% 2-propanol extract of black cohosh was used. RESULTS: Black cohosh extract (BcEx) stimulated the protein expression of PAI-1, but it did not affect that of t-PA. Vitamin E, a potent antioxidant, inhibited the BcEx-induced increase in PAI-1 expression, while ICI 182,780, an estrogen receptor antagonist, had no effect. Fibrin overlay zymography revealed that BcEx increased the activity of PAI-1 in the conditioned media, while concurrently decreasing that of free t-PA by inducing a binding to PAI-1. CONCLUSIONS: BcEx induces PAI-1 protein expression in the VSMCs likely via an oxidant mechanism. It also stimulates the enzyme activity of PAI-1 and reduces that of free t-PA. These findings suggest that black cohosh might exert a negative influence on fibrinolysis.

Lee DY; Roh CR; Kang YH; Choi D; Lee Y; Rhyu MR; Yoon BK

2013-09-01

142

Technetium-99m-labeled recombinant tissue plasminogen activator for the imaging of emboli in vivo  

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Tissue-type plasminogen activator (t-PA) effectively lyses activate thrombus by direct action. Recombinant t-PA (rt-PA) was labeled with technetium-99m ([sup 99m]Tc) to investigate the in vivo binding to fibrin clots in a feline cerebral embolism model created by insertion of an artificial fibrin clot within the carotid artery. [sup 99m]Tc-rt-PA administered intravenously provided clearer imaging of clots after priming with cold rt-PA, with uptake peaking 5-10 minutes after the injection. [sup 99m]Tc-labeled human serum albumin was not retained at clot sites. Systemically administered [sup 99m]Tc-rt-PA binds to fibrin clots within carotid arteries in our feline model. Our results suggest that the interaction of intrinsic plasminogen activator inhibitors with extrinsically administered rt-PA may regulate the demonstration of a clot, although the precise mechanism is unclear. (author).

Takahashi, Akihiro; Itoh, Kazuo; Tsukamoto, Eriko; Furudate, Masayori; Kamiyama, Hiroyasu; Abe, Hiroshi (Hokkaido Univ., Sapporo (Japan). School of Medicine)

1993-07-01

143

Technetium-99m-labeled recombinant tissue plasminogen activator for the imaging of emboli in vivo  

International Nuclear Information System (INIS)

Tissue-type plasminogen activator (t-PA) effectively lyses activate thrombus by direct action. Recombinant t-PA (rt-PA) was labeled with technetium-99m (99mTc) to investigate the in vivo binding to fibrin clots in a feline cerebral embolism model created by insertion of an artificial fibrin clot within the carotid artery. 99mTc-rt-PA administered intravenously provided clearer imaging of clots after priming with cold rt-PA, with uptake peaking 5-10 minutes after the injection. 99mTc-labeled human serum albumin was not retained at clot sites. Systemically administered 99mTc-rt-PA binds to fibrin clots within carotid arteries in our feline model. Our results suggest that the interaction of intrinsic plasminogen activator inhibitors with extrinsically administered rt-PA may regulate the demonstration of a clot, although the precise mechanism is unclear. (author)

1993-01-01

144

The role of the urokinase-type plasminogen activator (uPA) and its receptor (CD87) in lipodermatosclerosis.  

UK PubMed Central (United Kingdom)

BACKGROUND: Lipodermatosclerosis refers to a sclerosing panniculitis and dermopathy of the lower extremities sometimes seen in association with venous ulceration. Matrix metalloproteinases are implicated in the pathogenesis of venous leg ulcers and the in vitro activation of recombinant MMP-2 is controlled by the plasminogen activation system. To better understand the role of plasminogen activation in the pathogenesis of venous leg ulcers we investigated fibrinolytic factors and their inhibitors in tissue samples of lipodermatolsclerosis. METHODS: The expression and the functional state of the urokinase-type plasminogen activator (uPA), the tissue-type plasminogen activator (tPA), the urokinase receptor (CD87), the plasminogen activator inhibitors-1 and -2 (PAI-1 and PAI-2) were assayed using reverse transcription polymerase chain reaction, Western blot, fibrin zymography and immunohistochemistry analyses in tissue samples of lipodermatosclerosis. RESULTS: Our results provide direct evidence of elevated expression of uPA (p<0.01) and CD87 (p<0.01) mRNA and protein level in lipodermatosclerosis in comparison with healthy skin. By immunohistochemistry, elevated expression of uPA and CD87 could be detected. Fibrin zymography showed significantly elevated endogenous uPA activity (p<0.01) in liposclerotic lesions compared to healthy controls. CONCLUSION: Our findings indicate that elevated plasminogen activation in lipodermatosclerotic tissue may play a crucial role in the pathogenesis of venous leg ulceration.

Herouy Y; Aizpurua J; Stetter C; Dichmann S; Idzko M; Hofmann C; Gitsch G; Vanscheidt W; Schöpf E; Norgauer J

2001-07-01

145

TM5275 prolongs secreted tissue plasminogen activator retention and enhances fibrinolysis on vascular endothelial cells.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Elevated plasminogen activator inhibitor-1 (PAI-1) reduces fibrinolytic potential in plasma, contributing to thrombotic disease. Thus, inhibiting PAI-1 activity is clinically desirable. We recently demonstrated that tissue plasminogen activator (tPA) remains on the surface of vascular endothelial cells (VECs) after secretion in a heavy-chain dependent manner, which is essential for high fibrinolytic activity on the surface of VECs, and that PAI-1 dissociates retained tPA from the cell surface as a result of high-molecular weight complex formation. Based on the model whereby amounts of tPA and its equilibrium with PAI-1 dynamically change after exocytosis, we examined how TM5275, a newly synthesized small molecule PAI-1 inhibitor, modulated tPA retention and VEC surface-derived fibrinolytic activity using microscopic techniques. MATERIALS AND METHODS: The effects of TM5275 on the kinetics of the secretion and retention of green fluorescent protein (GFP)-tagged tPA (tPA-GFP) on VECs were analyzed using total internal reflection fluorescence microscopy. The effects of TM5275 on the generation of plasmin activity were evaluated by both plasminogen accumulation and fibrin clot lysis on tPA-GFP-expressing VECs using confocal laser scanning microscopy. RESULTS: TM5275 at concentrations of 20 and 100?M significantly prolonged the retention of tPA-GFP on VECs by inhibiting tPA-GFP-PAI-1 high-molecular-weight complex formation. TM5275 enhanced the time-dependent accumulation of plasminogen as well as the dissolution of fibrin clots on and around the tPA-GFP-expressing cells. CONCLUSIONS: The profibrinolytic effects of TM5275 were clearly demonstrated by the prolongation of tPA retention and enhancement of plasmin generation on the VEC surface as a result of PAI-1 inhibition.

Yasui H; Suzuki Y; Sano H; Suda T; Chida K; Dan T; Miyata T; Urano T

2013-07-01

146

Phorbol ester induces the biosynthesis of glycosylated and nonglycosylated plasminogen activator inhibitor 2 in high excess over urokinase-type plasminogen activator in human U-937 lymphoma cells  

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The tumor-promoting phorbol ester PMA induces changes in the histiocytic human lymphoma cell line U-937 akin to cellular differentiation and concomitantly stimulates the biosynthesis of plasminogen activator inhibitor 2 (PAI 2) and of urokinase-type plasminogen activator (u-PA). PAI 2 is found in a nonglycosylated intracellular and a glycosylated secreted form. The former appears to be identical to PAI 2 previously purified from placental extracts and large-scale U-937 cell cultures. The sixfold increase of PAI 2 antigen measured 24 h after PMA treatment in cell extracts and conditioned media is accompanied by an equal increase of active PAI 2 mRNA, whereas the 6 to 13-fold increase of u-PA antigen in the same samples is associated with only a 1.5-fold mRNA increase. The increase of PAI 2, but not of u-PA, biosynthesis requires transcription. A 50-fold molar excess of PAI 2 over u-PA is found in both extracts and conditioned media of PMA-treated cells. PAI 2 represents at least 0.3% of total de novo synthesized protein 24 h after induction with PMA. Thus, PAI 2, but not u-PA, is an abundant product of this precursor analogue of the mononuclear phagocyte lineage, and might represent a new marker for monocyte/macrophage differentiation.

Genton, C.; Kruithof, E.K.; Schleuning, W.D.

1987-03-01

147

Inhibitors of Urokinase Type Plasminogen Activator and Cytostatic Activity from Crude Plants Extracts  

Directory of Open Access Journals (Sweden)

Full Text Available In view of the clear evidence that urokinase type plasminogen activator (uPA) plays an important role in the processes of tumor cell metastasis, aortic aneurysm, and multiple sclerosis, it has become a target of choice for pharmacological intervention. The goal of this study was thus to determine the presence of inhibitors of uPA in plants known traditionally for their anti-tumor properties. Crude methanol extracts were prepared from the leaves of plants (14) collected from the subtropical dry forest (Guanica, Puerto Rico), and tested for the presence of inhibitors of uPA using the fibrin plate assay. The extracts that tested positive (6) were then partitioned with petroleum ether, chloroform, ethyl acetate and n-butanol, in a sequential manner. The resulting fractions were then tested again using the fibrin plate assay. Extracts from leaves of Croton lucidus (C. lucidus) showed the presence of a strong uPA inhibitory activity. Serial dilutions of these C. lucidus partitions were performed to determine the uPA inhibition IC50 values. The chloroform extract showed the lowest IC50 value (3.52 µg/mL) and hence contained the most potent uPA inhibitor. Further investigations revealed that the crude methanol extract and its chloroform and n-butanol partitions did not significantly inhibit closely related proteases such as the tissue type plasminogen activator (tPA) and plasmin, indicating their selectivity for uPA, and hence superior potential for medicinal use with fewer side effects. In a further evaluation of their therapeutic potential for prevention of cancer metastasis, the C. lucidus extracts displayed cytostatic activity against human pancreatic carcinoma (PaCa-2) cells, as determined through an MTS assay. The cytostatic activities recorded for each of the partitions correlated with their relative uPA inhibitory activities. There are no existing reports of uPA inhibitors being present in any of the plants reported in this study.

Xueqiang Zha; Ricardo Diaz; Jose Javier Rosado Franco; Veronica Forbes Sanchez; Ezio Fasoli; Gabriel Barletta; Augusto Carvajal; Vibha Bansal

2013-01-01

148

Inhibitors of urokinase type plasminogen activator and cytostatic activity from crude plants extracts.  

UK PubMed Central (United Kingdom)

In view of the clear evidence that urokinase type plasminogen activator (uPA) plays an important role in the processes of tumor cell metastasis, aortic aneurysm, and multiple sclerosis, it has become a target of choice for pharmacological intervention. The goal of this study was thus to determine the presence of inhibitors of uPA in plants known traditionally for their anti-tumor properties. Crude methanol extracts were prepared from the leaves of plants (14) collected from the subtropical dry forest (Guanica, Puerto Rico), and tested for the presence of inhibitors of uPA using the fibrin plate assay. The extracts that tested positive (6) were then partitioned with petroleum ether, chloroform, ethyl acetate and n-butanol, in a sequential manner. The resulting fractions were then tested again using the fibrin plate assay. Extracts from leaves of Croton lucidus (C. lucidus) showed the presence of a strong uPA inhibitory activity. Serial dilutions of these C. lucidus partitions were performed to determine the uPA inhibition IC?? values. The chloroform extract showed the lowest IC?? value (3.52 µg/mL) and hence contained the most potent uPA inhibitor. Further investigations revealed that the crude methanol extract and its chloroform and n-butanol partitions did not significantly inhibit closely related proteases such as the tissue type plasminogen activator (tPA) and plasmin, indicating their selectivity for uPA, and hence superior potential for medicinal use with fewer side effects. In a further evaluation of their therapeutic potential for prevention of cancer metastasis, the C. lucidus extracts displayed cytostatic activity against human pancreatic carcinoma (PaCa-2) cells, as determined through an MTS assay. The cytostatic activities recorded for each of the partitions correlated with their relative uPA inhibitory activities. There are no existing reports of uPA inhibitors being present in any of the plants reported in this study.

Zha X; Diaz R; Franco JJ; Sanchez VF; Fasoli E; Barletta G; Carvajal A; Bansal V

2013-01-01

149

Expression, purification and characterization of recombinant plasminogen activator from Gloydius brevicaudus venom in Escherichia coli.  

UK PubMed Central (United Kingdom)

The plasminogen activator (PA) in snake venom, a serine protease, can convert plasminogen to active plasmin, indirectly causing the degradation of fibrin. It is difficult to purify sufficient snake venom PA (SV-PA) for clinical applications due to the low SV-PA content in venom. The gene encoding PA was obtained from the venom gland of Gloydius brevicaudus using RT-PCR with primers designed according to the N-terminal amino acids of G. brevicaudus venom PA (GBV-PA), was cloned into the prokaryotic expression vector pET-42a, and recombinant GBV-PA (rGBV-PA) was expressed via Isopropyl-?-d-1-Thiogalactopyranoside (IPTG) induction. Like human tissue PA, the purified renatured rGBV-PA could significantly reduce the rabbit plasma euglobulin lysis time (ELT) and prevent thrombus formation in the inferior vena cava of rats. Within the dosage range, the dosage and effects were positively correlated.

Zhang J; Meng W; Wang C; Wu Z; Wu G; Xu Y

2013-09-01

150

Structural insight into inactivation of plasminogen activator inhibitor-1 by a small-molecule antagonist.  

UK PubMed Central (United Kingdom)

Plasminogen activator inhibitor-1 (PAI-1), a serpin, is the physiological inhibitor of tissue-type and urokinase-type plasminogen activators and thus also an inhibitor of fibrinolysis and tissue remodeling. It is a potential therapeutic target in many pathological conditions, including thrombosis and cancer. Several types of PAI-1 antagonist have been developed, but the structural basis for their action has remained largely unknown. Here we report X-ray crystal structure analysis of PAI-1 in complex with a small-molecule antagonist, embelin. We propose a mechanism for embelin-induced rapid conversion of PAI-1 into a substrate for its target proteases and the subsequent slow conversion of PAI-1 into an irreversibly inactivated form. Our work provides structural clues to an understanding of PAI-1 inactivation by small-molecule antagonists and an important step toward the design of drugs targeting PAI-1.

Lin Z; Jensen JK; Hong Z; Shi X; Hu L; Andreasen PA; Huang M

2013-02-01

151

Expression, purification and characterization of recombinant plasminogen activator from Gloydius brevicaudus venom in Escherichia coli.  

Science.gov (United States)

The plasminogen activator (PA) in snake venom, a serine protease, can convert plasminogen to active plasmin, indirectly causing the degradation of fibrin. It is difficult to purify sufficient snake venom PA (SV-PA) for clinical applications due to the low SV-PA content in venom. The gene encoding PA was obtained from the venom gland of Gloydius brevicaudus using RT-PCR with primers designed according to the N-terminal amino acids of G. brevicaudus venom PA (GBV-PA), was cloned into the prokaryotic expression vector pET-42a, and recombinant GBV-PA (rGBV-PA) was expressed via Isopropyl-?-d-1-Thiogalactopyranoside (IPTG) induction. Like human tissue PA, the purified renatured rGBV-PA could significantly reduce the rabbit plasma euglobulin lysis time (ELT) and prevent thrombus formation in the inferior vena cava of rats. Within the dosage range, the dosage and effects were positively correlated. PMID:23891573

Zhang, Jinhua; Meng, Wenli; Wang, Chunhua; Wu, Zhiqiang; Wu, Guotu; Xu, Yunlu

2013-07-23

152

Purification and activation of caprine and canine plasminogens: Comparison with human plasminogen/ Purificación y activación de los plasminógenos caprino y canino: comparación con el plasminógeno humano  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Objetivo: unificar la purificación y activación de los plasminógenos de tres especies diferentes, a saber: humana, caprina y canina. Materiales y métodos: se usaron Lysina-Sefarosa 4B y Sefacel DEAE para las cromatografías de afinidad y de intercambio iónico, respectivamente. Se determinó la secuencia terminal-N tanto de los plasminógenos intactos como de los degradados. Resultados: en las tres especies se identificaron bandas de 92 kDa correspondientes a los plas (more) minógenos nativos. Se halló que sus secuencias terminales-N eran EPLDDY, DPLDDY y XXLDDY para los plasminógenos humano, caprino y canino, respectivamente. Además, se purificaron los plasminógenos degradados circulantes, cuyas secuencias terminales-N fueron, en el mismo orden, KVYLSE, RITLL Y RIYSL. Conclusión: la activación de los tres plasminógenos confirmó la formación de las bandas electroforéticas típicas de la plasmina humana correspondientes a las cadenas pesada A y liviana B, que también se identificaron en las plasminas caprina y canina. Este nuevo método de purificación facilita la comparación y el esclarecimiento de los sistemas fibrinolíticos de los mamíferos. Abstract in english Objective: To unify the purification and activation of plasminogens from three different species, namely: human, caprine and canine. Materials and methods: Lysine-Sepharose 4B and sephacel DEAE were used, for affinity and ion-exchange chromatography, respectively. The N-terminal sequence was determined for both the intact and degraded plasminogens. Results: Bands of 92 kDa corresponding to native plasminogens were identified in the three species. Their N-terminal sequence (more) s were found to be EPLDDY, DPLDDY and XXLDDY for human, caprine and canine plasminogen, respectively. Furthermore, the degraded in vivo circulating plasminogens from the three species were purified and their N-terminal sequences were KVYLSE, RITLL and RIYLS for the human, caprine and canine, in that order. Conclusion: Activation of the three plasminogens confirmed the formation of the typical electrophoretic bands for human plasmin corresponding to the heavy A and the light B chains which were also identified in the caprine and canine plasmins. This new purification methodology facilitates the comparison and further elucidation of the fibrinolytic systems in mammals.

Cañas Bermúdez, Omaira; Quijano Parra, Alfonso; Arbeláez Ramírez, Luis Fernando

2011-06-01

153

Keratinocytes and head and neck squamous cell carcinoma cells regulate urokinase-type plasminogen activator and plasminogen activator inhibitor-1 in fibroblasts.  

UK PubMed Central (United Kingdom)

BACKGROUND: To investigate possible differences in the effects of soluble factors from oral squamous cell carcinoma (SCC) cells (UT-SCC-87) and normal oral keratinocytes (NOK) on fibroblast expression of genes involved in tumor stroma turnover. MATERIALS AND METHODS: Transwell co-cultures with fibroblasts in collagen gels, and SCC cells or NOK in inserts were carried out. Fibroblast gene expression was measured with real-time polymerase chain reaction (PCR). RESULTS: The expression of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) was up-regulated in co-cultures with SCC cells but not with NOK. In contrast, both SCC cells and NOK regulated matrix metalloproteinase-1 (MMP1) and -3, and tissue inhibitor of metalloproteinases-2 (TIMP2) and -3 to a similar extent, while MMP2 and TIMP1 were largely unaffected. Interleukin 1 alpha (IL1?) up-regulated both MMP1 and MMP3 and down-regulated PAI-1, TIMP2 and -3. CONCLUSION: SCC and NOK regulate fibroblast expression of genes involved in tumor stroma turnover differentially in vitro. These observations may contribute to a better understanding of the mechanisms behind extracellular matrix turnover in tumors.

Hakelius M; Koskela A; Ivarsson M; Grenman R; Rubin K; Gerdin B; Nowinski D

2013-08-01

154

Characterization and purification of tissue plasminogen activator and its binding to the surface of cerebellar neutrons  

Energy Technology Data Exchange (ETDEWEB)

Early studies directed at understanding the possible role of the fibrinolytic system in the brain had demonstrated the production of plasminogen activator (PA) by developing mouse cerebellum. This thesis describes neuronal PA as being primarily tissue plasminogen activator (tPA). This tPA was isolated from a mouse neuronal cell line, and a highly specific antibody was developed in rabbits. The antibody isolated from rabbit antiserum effectively and specifically inhibits murine tPA and blocks the catalytic activity of both the intact molecule and its B-chain, while exhibiting little or nor reactivity with mouse or human urokinase (uPA), human plasmin or plasminogen. This antibody was used as an immunoaffinity ligand to obtain highly purified murine tPA to investigate further the interactions of the protein with cerebellar neurons. Using {sup 125}I-tPA, the high-affinity binding to cerebellar granule neurons is rapid, time-dependent, saturable, reversible and specific for tPA but not for other related serine proteases. Neither the catalytic site nor the carbohydrate moiety of tPA appear to be involved in the binding. Autoradiography shows the specific tPA binding is to granule neurons in these cultures.

Verrall, S.B.

1989-01-01

155

Characterization and purification of tissue plasminogen activator and its binding to the surface of cerebellar neutrons  

International Nuclear Information System (INIS)

Early studies directed at understanding the possible role of the fibrinolytic system in the brain had demonstrated the production of plasminogen activator (PA) by developing mouse cerebellum. This thesis describes neuronal PA as being primarily tissue plasminogen activator (tPA). This tPA was isolated from a mouse neuronal cell line, and a highly specific antibody was developed in rabbits. The antibody isolated from rabbit antiserum effectively and specifically inhibits murine tPA and blocks the catalytic activity of both the intact molecule and its B-chain, while exhibiting little or nor reactivity with mouse or human urokinase (uPA), human plasmin or plasminogen. This antibody was used as an immunoaffinity ligand to obtain highly purified murine tPA to investigate further the interactions of the protein with cerebellar neurons. Using 125I-tPA, the high-affinity binding to cerebellar granule neurons is rapid, time-dependent, saturable, reversible and specific for tPA but not for other related serine proteases. Neither the catalytic site nor the carbohydrate moiety of tPA appear to be involved in the binding. Autoradiography shows the specific tPA binding is to granule neurons in these cultures.

1989-01-01

156

Taming neonatal hypoxic-ischemic brain injury by intranasal delivery of plasminogen activator inhibitor-1.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: Plasminogen activator inhibitor-I (PAI-1), a ?50-kDa serine protease inhibitor, markedly reduces the extravascular toxicity of tissue-type plasminogen activator in experimental hypoxic-ischemic (HI) brain injury of newborns. However, the current treatment with PAI-1 requires intracerebroventricle injection to cross the blood-brain barrier, which is an invasive procedure of limited clinical potential. Thus, we tested whether intranasal administration of PAI-1 can bypass blood-brain barrier and mitigate neonatal HI brain injury. METHODS: Rat pups were subjected to HI, with or without lipopolysaccharide pre-exposure, followed by intranasal delivery of a stable-mutant form of PAI-1 (CPAI). RESULTS: Immunoblotting showed that CPAI sequentially entered the olfactory bulbs and cerebral cortex after intranasal delivery and reduced ?75% of brain atrophy in HI or lipopolysaccharide-sensitized HI injury. Mechanistically, CPAI attenuated HI-induced plasminogen activators and lipopolysaccharide/HI-induced nuclear factor-?B signaling, neuroinflammation, and blood-brain barrier permeability. CONCLUSIONS: Intranasal delivery of CPAI is an effective treatment of experimental HI brain injury of newborns. Clinical application of this experimental therapy merits further investigation.

Yang D; Sun YY; Lin X; Baumann JM; Warnock M; Lawrence DA; Kuan CY

2013-09-01

157

Nuclear magnetic resonance solution structure of the plasminogen-activator protein staphylokinase.  

UK PubMed Central (United Kingdom)

Staphylokinase, a 15.5 kDa protein from Staphylococcus aureus, is a plasminogen activator which is currently undergoing clinical trials for the therapy of myocardial infarction and peripheral thrombosis. The three-dimensional (3D) NMR solution structure has been determined by multidimensional heteronuclear NMR spectroscopy on uniformly 15N- and 15N,13C-labeled samples of staphylokinase. Structural constraints were obtained from 82 3JHNH alpha as well as 22 3JNH beta scalar coupling constants and 2345 NOE cross-peaks, derived from 15N-edited and 13C-edited 3D NOE spectra. NOE cross-peak assignments were confirmed by analysis of ¿15N,13C¿-edited and ¿13C,13C¿-edited 4D NOE spectra. The structure is presented as a family of 20 conformers which show an average rmsd of 1.02 +/- 0.15 A from the mean structure for the backbone atoms. The tertiary structure of staphylokinase shows a well-defined global structure consisting of a central 13-residue alpha-helix flanked by a two-stranded beta-sheet, both of which are located above a five-stranded beta-sheet. Two of the connecting loops exhibit a higher conformational heterogeneity. Overall, staphylokinase shows a strong asymmetry of hydrophilic and hydrophobic surfaces. The N-terminal sequence, including Lys10 which is the site of the initial proteolytic cleavage during activation of plasminogen, folds back onto the protein core, thereby shielding amino acids with functional importance in the plasminogen activation process. From a comparison of the structure with mutational studies, a binding region for plasminogen is proposed.

Ohlenschläger O; Ramachandran R; Gührs KH; Schlott B; Brown LR

1998-07-01

158

Preliminary crystallographic study on a low molecular weight form of bacterial plasminogen activator staphylokinase.  

UK PubMed Central (United Kingdom)

Staphylokinase, a 17 kDa protein, produced by certain strains of Staphylococcus aureus functions as a fibrin-specific plasminogen activator. During its interaction with plasminogen, staphylokinase is converted into a low molecular weight form by loss of ten amino-terminal residues. This low molecular weight form of recombinant staphylokinase has been crystallized using the hanging-drop vapor-diffusion technique with polyethylene glycol 4000 as precipitant. Crystals belong to the orthorhombic space group C222(1) with unit-cell dimensions a = 43.78, b = 59.86 and c = 103.25 A and one molecule in the asymmetric unit. These crystals diffract to about 2.4 A resolution.

Chattopadhyay D; Stewart JE; Smith CD; DeLucas LJ; Narayana SV

1997-07-01

159

Identification and characterization of human endothelial cell membrane binding sites for tissue plasminogen activator and urokinase.  

UK PubMed Central (United Kingdom)

Cultured human endothelial cells synthesize and secrete two types of plasminogen activator, tissue plasminogen activator (t-PA) and urokinase (u-PA). Previous work from this laboratory (Hajjar, K.A., Hamel, N. M., Harpel, P. C., and Nachman, R. L. (1987) J. Clin. Invest. 80, 1712-1719) has demonstrated dose-dependent, saturable, and high affinity binding of t-PA to two sites associated with cultural endothelial cell monolayers. We now report that an isolated plasma membrane-enriched endothelial cell fraction specifically binds 125I-t-PA at a single saturable site (Kd 9.1 nM; Bmax 3.1 pmol/mg membrane protein). Ligand blotting experiments demonstrated that both single and double-chain t-PA specifically bound to a Mr 40,000 membrane protein present in detergent extracts of isolated membranes, while high molecular weight, low molecular weight, and single-chain u-PA associated with a Mr 48,000 protein. Both binding interactions were reversible and cell-specific and were inhibitable by pretreatment of intact cells with nanomolar concentrations of trypsin. The relevant binding proteins were not found in subendothelial cell matrix, failed to react with antibodies to plasminogen activator inhibitor type 1 and interacted with their respective ligands in an active site-independent manner. The isolated t-PA binding site was resistant to reduction and preserved the capacity for plasmin generation. In contrast, the isolated u-PA binding protein was sensitive to reduction, and did not maintain the catalytic activity of the ligand on the blot. The results suggest that in addition to sharing a matrix-associated binding site (plasminogen activator inhibitor type 1), both t-PA and u-PA have unique membrane binding sites which may regulate their function. The results also provide further support for the hypothesis that plasminogen and t-PA can assemble on the endothelial cell surface in a manner which enhances cell surface generation of plasmin.

Hajjar KA; Hamel NM

1990-02-01

160

The Single Substitution I259T, Conserved in the Plasminogen Activator Pla of Pandemic Yersinia pestis Branches, Enhances Fibrinolytic Activity ?  

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The outer membrane plasminogen activator Pla of Yersinia pestis is a central virulence factor in plague. The primary structure of the Pla ?-barrel is conserved in Y. pestis biovars Antiqua, Medievalis, and Orientalis, which are associated with pandemics of plague. The Pla molecule of the ancestral Y...

Haiko, Johanna; Kukkonen, Maini; Ravantti, Janne J.; Westerlund-Wikström, Benita; Korhonen, Timo K.

 
 
 
 
161

Activators of plasminogen and the progression of small abdominal aortic aneurysms  

DEFF Research Database (Denmark)

The aim of this study was to examine the role of activating pathways of plasminogen in the natural history of abdominal aortic aneurysms (AAA). To fulfill this objective 70 male patients with small AAA (> 3 cm) were interviewed and examined. Their blood samples were taken at diagnosis. The patients were scanned annually for a minimum period of 1 year and a maximum of 5 years (mean 2.5 years), and referred for surgery if the AAA exceeded 5 cm in diameter. Plasma levels of urokinase-like plasminogen activator (uPA), tissue-type plasminogen activator (tPA), plasminogen-activator-inhibitor-1 (PAI-1), macrophage-inhibiting factor (MIF), transforming-growth-factor-beta1 (TGF-beta1), homocysteine, and serum levels of IgA-antibodies against Chlamydia pneumoniae (IgA-CP) and cotinine (a nicotine metabolite) were measured. The annual expansion rate correlated positively with tPA, IgA-CP, and S-cotinine; rho = 0.37 (P = 0.004), 0.28 (P = 0.01), and 0.24 (P = 0.04), while PAI-1, uPA, TGF-beta1, homocysteine, and MIF did not. S-cotinine and PAI-1 also correlated positively with tPA, rho = 0.24 (P = 0.04), and 0.33 (P = 0.005). IgA-CP did not correlate with tPA. By receiver operating characteristics (ROC) curve analysis, tPA showed to be predictive of cases expanding to above 5 cm within the first 5 years with an optimal sensitivity and specificity of 0.73 and 0.71, respectively (P = 0.015). The aortic matrix degradation in AAA may be partly caused by an activation of plasminogen by tPA, but not by uPA, which usually dominates matrix degradation. Smoking seems to be an important factor for this pathway, while the pathway of IgA-CP seems different.

Lindholt, Jes Sanddal

2006-01-01

162

In vivo and in vitro expression of the plasminogen activators and urokinase type plasminogen activator receptor (u-PAR) in the pig oviduct.  

Science.gov (United States)

Plasminogen activator activities have previously been reported in oviductal fluid. At present the question was whether the source of these activities is molecules come from blood plasma or if these activators are synthesized by the oviduct. Gene expression and protein synthesis of urokinase type (u-PA) and tissue type (t-PA) occur in different regions of the pig oviduct. Their relative concentrations do not vary between the ampulla and isthmus regions and are similar throughout the estrous cycle. However, while relative amounts of t-PA mRNA were not different between the different stages of the estrous cycle, u-PA mRNA was greater after ovulation (P<0.05). Regarding the function of u-PA, its receptor (u-PAR) was distinguished by immunohistochemistry at the apical region of the epithelial cells and was more noticeable in the isthmus. Expression of u-PA, t-PA, u-PAR and PAI-1 genes in primary oviductal epithelial cell cultures was studied under 17-?-estradiol (100 pg/ml) and progesterone (100 ng/ml). u-PA mRNA increased in the presence of progesterone (P<0.05), but not by action of 17-?-estradiol. t-PA, PAI-1 and u-PAR were similar when cultured with the hormones. These results suggest that u-PA could be regulated by progesterone at a transcriptional level, by the balance of their activity for PAI-1 or at the epithelial surface through the binding of u-PAR. In conclusion, plasminogen activation system components might cooperate in the oviductal lumen to control plasmin generation. PMID:23103014

Roldán-Olarte, Mariela; García, Daniela C; Jiménez-Díaz, María; Valdecantos, Pablo A; Miceli, Dora C

2012-10-05

163

Prognostic significance of urokinase plasminogen activator and plasminogen activator inhibitor-1 mRNA expression in lymph node- and hormone receptor-positive breast cancer  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background One of the most thoroughly studied systems in relation to its prognostic relevance in patients with breast cancer, is the plasminogen activation system that comprises of, among others, the urokinase Plasminogen Activator (uPA) and its main inhibitor, the Plasminogen Activator Inhibitor-1 (PAI-1). In this study, we investigated the prognostic value of uPA and PAI-1 at the mRNA level in lymph node- and hormone receptor-positive breast cancer. Methods The study included a retrospective series of 87 patients with hormone-receptor positive and axillary lymph node-positive breast cancer. All patients received radiotherapy, adjuvant anthracycline-based chemotherapy and five years of tamoxifen treatment. The median patient age was 54 and the median follow-up time was 79 months. Distant relapse occurred in 30 patients and 22 patients died from breast cancer during follow-up. We investigated the prognostic value of uPA and PAI-1 at the mRNA level as measured by real-time quantitative RT-PCR. Results uPA and PAI-1 gene expression was not found to be correlated with any of the established clinical and pathological factors. Metastasis-free Survival (MFS) and Breast Cancer specific Survival (BCS) were significantly shorter in patients expressing high levels of PAI-1 mRNA (p PAI-1 mRNA appeared to be the strongest prognostic factor for MFS (Hazard Ratio (HR) = 10.12; p = 0.0002) and for BCS (HR = 13.17; p = 0.0003). Furthermore, uPA gene expression was not significantly associated neither with MFS (p = 0.41) nor with BCS (p = 0.19). In a Cox-multivariate regression analysis, uPA expression did not demonstrate significant independent prognostic value. Conclusion These findings indicate that high PAI-1 mRNA expression represents a strong and independent unfavorable prognostic factor for the development of metastases and for breast cancer specific survival in a population of hormone receptor- and lymph node-positive breast cancer patients.

Leissner Philippe; Verjat Thibault; Bachelot Thomas; Paye Malick; Krause Alexander; Puisieux Alain; Mougin Bruno

2006-01-01

164

Increased plasminogen activator inhibitor activity in non insulin dependent diabetic patients--relationship with plasma insulin.  

UK PubMed Central (United Kingdom)

Type 2 diabetic patients are known to frequently have a high insulin level and were recently described as having high plasminogen activator inhibitor (PAI) activity, compared to normal controls. As we have shown in several clinical conditions (normal subjects, obese patients, angina pectoris patients) that plasma PAI activity was linked with plasma insulin, we have studied in 38 type 2 diabetic patients the relationship between PAI activity, insulin and other parameters. Patients showed higher level of PAI activity, as well as plasma glucose, insulin, triglyceride, cholesterol and Apolipoprotein B levels than normal controls; highest values were observed with diabetic patients also affected by coronary artery disease. A significant correlation was found between PAI activity and insulin (r = 0.60, p less than 0.001), body mass index (r = 0.32, p less than 0.05) and Apolipoprotein B (r = 0.33, p less than 0.05). The two latter correlations disappeared after adjustment for insulin. These results are in agreement with our previous report showing an in vitro effect of insulin on the synthesis of PAI by a hepatocellular cell line. Hyperinsulinemia presented by type 2 diabetic patients may increase the hepatic synthesis of PAI, inducing an hypofibrinolysis, which could play a role in the development of the vascular complications. Attempts to reduce hyperinsulinemia could have a favorable effect by lowering PAI activity.

Juhan-Vague I; Roul C; Alessi MC; Ardissone JP; Heim M; Vague P

1989-06-01

165

Plasminogen interaction with Trypanosoma cruzi  

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Full Text Available The ability of Trypanosoma cruzi to interact with plasminogen, the zimogenic form of the blood serin protease plasmin, was examined. Immunohistochemistry studies revealed that both forms, epimastigotes and metacyclic trypomastigotes, were able to fix plasminogen in a lysine dependant manner. This interaction was corroborated by plasminogen activation studies. Both forms of the parasite enhanced the plasminogen activation by tissue-type plasminogen activator.The maximal enhancements obtained were 15-fold and 3.4-fold with epimastigotes and metacyclic trypomastigotes, respectively, as compared to plasminogen activation in absence of cells. Ligand-blotting analysis of proteins extracted with Triton X-114 from a microsomal fraction of epimastigotes revealed at least five soluble proteins and one hydrophobic protein able to bind plasminogen.

Almeida Laura; Vanegas Gilmer; Calcagno Marina; Concepción Juan Luis; Avilan Luisana

2004-01-01

166

Mechanism of action of omega-amino acids on plasminogen activation and fibrinolysis induced by staphylokinase.  

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Stimulation of Lys-plasminogen (Lys-Pg) and Glu-plasminogen (Glu-Pg) activation under the action of staphylokinase and Glu-Pg activation under the action of preformed plasmin-staphylokinase activator complex (Pm-STA) by low concentrations and inhibition by high concentrations of omega-amino acids (>90-140 mM) were found. Maximal stimulation of the activation was observed at concentrations of L-lysine, 6-aminohexanoic acid (6-AHA), and trans-(4-aminomethyl)cyclohexanecarboxylic acid 8.0, 2.0, and 0.8 mM, respectively. In contrast, the Lys-Pg activation rate by Pm-STA complex sharply decreased when concentrations of omega-amino acids exceeded the above-mentioned values. It was found that formation of Pm-STA complex from a mixture of equimolar concentrations of staphylokinase and Glu-Pg or Lys-Pg is stimulated by low concentrations (maximal at 10 mM) of 6-AHA. Negligible increase in the specific activities of plasmin and Pm-STA complex was detected at higher concentrations of 6-AHA (to maximal at 70 and 50 mM, respectively). Inhibitory effects of omega-amino acids on the rate of fibrinolysis induced by staphylokinase, Pm-STA complex, and plasmin were compared. It was found that inhibition of staphylokinase-induced fibrinolysis by omega-amino acids includes blocking of the reactions of Pm-STA complex formation, plasminogen activation by this complex, and lysis of fibrin by forming plasmin as a result of displacement of plasminogen and plasmin from the fibrin surface. Thus, the slow stage of Pm-STA complex formation plays an important role in the mechanism of action of omega-amino acids on Glu-Pg activation and fibrinolysis induced by staphylokinase. In addition to alpha-->beta change of Glu-Pg conformation, stimulation of Pm-STA complex formation leads to increase in Glu-Pg activation rate in the presence of low concentrations of omega-amino acids. Inhibition of Pm-STA complex formation on fibrin surface by omega-amino acids is responsible for appearance of long lag phases on curves of fibrinolysis induced by staphylokinase. PMID:17680762

Levashov, M Yu; Aisina, R B; Gershkovich, K B; Varfolomeyev, S D

2007-07-01

167

Key role of tissue plasminogen activator in neurovascular coupling  

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The increase in blood flow evoked by synaptic activity is essential for normal brain function and underlies functional brain imaging signals. Nitric oxide, a vasodilator released by NMDA receptor activation, is critical for the flow increase, but the factors linking NMDA receptor activity to nitric ...

Park, Laibaik; Gallo, Eduardo F.; Anrather, Josef; Wang, Gang; Norris, Erin H.; Paul, Justin; Strickland, Sidney

168

Impact of intraperitoneal pressure and duration of surgery on levels of tissue plasminogen activator and plasminogen activator inhibitor-1 mRNA in peritoneal tissues during laparoscopic surgery.  

UK PubMed Central (United Kingdom)

BACKGROUND: Our objective was to evaluate the impact of intraperitoneal pressure (IPP) and duration of a CO(2) pneumoperitoneum on the peritoneal fibrinolytic system during laparoscopic surgery. METHODS: Human study: Patients undergoing laparoscopic surgery were divided into two groups: low (8 mmHg, n= 32) or standard (12 mmHg, n= 36) IPP. Normal peritoneum was collected from the parietal wall at the beginning of surgery and every 60 min thereafter. Mouse study: Mice were divided into three groups: low (2 mmHg) or high (8 mmHg) IPP or laparotomy. Peritoneal tissue was collected at 0, 4, 8, 24, 48 and 72 h, and 5 and 7 days after surgery. Real-time RT-PCR was performed in humans and mice to measure the levels of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) mRNA in peritoneal tissues. RESULTS: Human study: The tPA/PAI-1 mRNA ratio was significantly decreased in the 12 mmHg group at 1 h [P < 0.0001 versus matched initial peritoneal biopsies (MI)]. The tPA/PAI-1 mRNA ratio decreased in both groups at 2 h (P < .0.01 versus MI). Mouse study: The tPA/PAI-1 ratio was decreased at 0 h, and the difference was significant at 4 h in both the laparotomy (P < 0.001 versus controls, 0 h, 5 and 7 days) and high-IPP (P < 0.0001 versus 0, 48 and 72 h, 5 and 7 days) groups. No changes in tPA/PAI-1 ratio were observed in the low-IPP group. CONCLUSIONS: A low IPP and shorter duration of surgery appear to minimally impact the fibrinolytic system during a CO? pneumoperitoneum.

Matsuzaki S; Botchorishvili R; Jardon K; Maleysson E; Canis M; Mage G

2011-05-01

169

Production of vampire bat plasminogen activator DSPA alpha 1 in CHO and insect cells.  

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Salivary plasminogen activator from the vampire bat Desmodus rotundus (DSPA alpha 1) is a promising new thrombolytic agent. Continuous growth of a stably transfected, methotrexate amplified, dhfr- CHO cell line yields up to 60 mg l-1 of DSPA alpha 1. Utilizing an engineered baculovirus 10 mg l-1 were produced in batches of Sf9 insect cells. Recombinant DSPA alpha 1 is purified from both sources using a one-step purification protocol. Although differences in glycosylation were detected, enzymatic activity and fibrin cofactor dependency are unaffected when DSPA alpha 1 derived from the two expression systems is compared. PMID:7766013

Petri, T; Langer, G; Bringmann, P; Cashion, L; Shallow, S; Schleuning, W D; Donner, P

1995-02-21

170

Plasminogen activator inhibitor-1 promotes synaptogenesis and protects against a?(1-42)-induced neurotoxicity in primary cultured hippocampal neurons.  

UK PubMed Central (United Kingdom)

Plasminogen activator inhibitor-1 (PAI-1) is a soluble factor that is released from astrocytes, the most abundant type of glial cell in the brain. PAI-1 was initially identified as inhibiting two types of plasminogen activators, that is, tissue-type plasminogen and urokinase activators that are known to lead to the proteolytic degradation of the extracellular matrix. Recently, PAI-1 was reported to mediate the neuroprotective activity of transforming growth factor-?1 against N-methyl-D-aspartate receptor-mediated excitotoxicity and to be involved in angiogenesis following ischemic stroke, independently of the effects via the inhibition of tissue-type plasminogen and urokinase-type plasminogen activators. In this study, we examined whether PAI-1 influences synaptogenesis and neurotoxicity induced by amyloid beta peptide(1-42) (Aß(1-42)) in rat primary hippocampal neurons. Using immunostaining, treatment with PAI-1 for 24 h was found to significantly upregulate synaptophysin, postsynaptic density-95, and the polysialylated form of neural cell adhesion molecule, compared to treatment with vehicle alone. In addition, PAI-1 has neuroprotective effects against A?(1-42)-induced cytotoxicity in rat primary cultured hippocampal neurons. Taken together, our results suggest that PAI-1 has therapeutic potential in Alzheimer's disease by promoting synaptogenesis and by demonstrating neuroprotective effects against A?(1-42)-oligomer-induced neurotoxicity in rat primary cultured hippocampal neurons.

Cho H; Joo Y; Kim S; Woo RS; Lee SH; Kim HS

2013-01-01

171

Distal hinge of plasminogen activator inhibitor-1 involves its latency transition and specificities toward serine proteases  

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Full Text Available Abstract Background The plasminogen activator inhibitor-1 (PAI-1) spontaneously converts from an inhibitory into a latent form. Specificity of PAI-1 is mainly determined by its reactive site (Arg346-Met347), which interacts with serine residue of tissue-type plasminogen activator (tPA) with concomitant formation of SDS-stable complex. Other sites may also play roles in determining the specificity of PAI-1 toward serine proteases. Results To understand more about the role of distal hinge for PAI-1 specificities towards serine proteases and for its conformational transition, wild type PAI-1 and its mutants were expressed in baculovirus system. WtPAI-1 was found to be about 12 fold more active than the fibrosarcoma PAI-1. Single site mutants within the Asp355-Arg356-Pro357 segment of PAI-1 yield guanidine activatable inhibitors (a) that can still form SDS stable complexes with tPA and urokinase plasminogen activator (uPA), and (b) that have inhibition rate constants towards plasminogen activators which resemble those of the fibrosarcoma inhibitor. More importantly, latency conversion rate of these mutants was found to be ~3–4 fold faster than that of wtPAI-1. We also tested if Glu351 is important for serine protease specificity. The functional stability of wtPAI-1, Glu351Ala, Glu351Arg was about 18 ± 5, 90 ± 8 and 14 ± 3 minutes, respectively, which correlated well with both their corresponding specific activities (84 ± 15 U/ug, 112 ± 18 U/ug and 68 ± 9 U/ug, respectively) and amount of SDS-stable complex formed with tPA after denatured by Guanidine-HCl and dialyzed against 50 mM sodium acetate at 4°C. The second-order rate constants of inhibition for uPA, plasmin and thrombin by Glu351Ala and Glu351Arg were increased about 2–10 folds compared to wtPAI-1, but there was no change for tPA. Conclusion The Asp355-Pro357 segment and Glu351 in distal hinge are involved in maintaining the inhibitory conformation of PAI-1. Glu351 is a specificity determinant of PAI-1 toward uPA, plasmin and thrombin, but not for tPA.

Wang Qingcai; Shaltiel Shmuel

2003-01-01

172

The role of plasminogen activator inhibitor-1 in gastric mucosal protection.  

Science.gov (United States)

Gastric mucosal health is maintained in response to potentially damaging luminal factors. Aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) disrupt protective mechanisms leading to bleeding and ulceration. The plasminogen activator system has been implicated in fibrinolysis following gastric ulceration, and an inhibitor of this system, plasminogen activator inhibitor (PAI)-1, is expressed in gastric epithelial cells. In Helicobacter pylori-negative patients with normal gastric histology taking aspirin or NSAIDs, we found elevated gastric PAI-1 mRNA abundance compared with controls; the increase in patients on aspirin was independent of whether they were also taking proton pump inhibitors. In the same patients, aspirin tended to lower urokinase plasminogen activator mRNA. Immunohistochemistry indicated PAI-1 localization to epithelial cells. In a model system using MKN45 or AGS-GR cells transfected with a PAI-1 promoter-luciferase reporter construct, we found no evidence for upregulation of PAI-1 expression by indomethacin, and, in fact, cyclooxygenase products such as PGE2 and PGI2 weakly stimulated expression. Increased gastric PAI-1 mRNA was also found in mice following gavage with ethanol or indomethacin, but plasma PAI-1 was unaffected. In PAI-1(-/-) mice, gastric hemorrhagic lesions in response to ethanol or indomethacin were increased compared with C57BL/6 mice. In contrast, in PAI-1-H/K? mice in which PAI-1 is overexpressed in parietal cells, there were decreased lesions in response to ethanol and indomethacin. Thus, PAI-1 expression is increased in gastric epithelial cells in response to mucosal irritants such as aspirin and NSAIDs probably via an indirect mechanism, and PAI-1 acts as a local autoregulator to minimize mucosal damage. PMID:23494120

Kenny, Susan; Steele, Islay; Lyons, Suzanne; Moore, Andrew R; Murugesan, Senthil V; Tiszlavicz, Laszlo; Dimaline, Rod; Pritchard, D Mark; Varro, Andrea; Dockray, Graham J

2013-03-14

173

Low-M(r) urokinase-type plasminogen activator as a reporter protein.  

Science.gov (United States)

A reporter plasmid coding for the low-molecular-weight (low-M(r)) form of single-chain urokinase-type plasminogen activator (low-M(r) u-PA; Leu144-Leu411) has been constructed and used to analyze promoter activity. Vectors containing the low-M(r) u-PA cDNA coupled to hormone-responsive promoters were introduced to mammalian cells. Following hormone treatment, the activity of the secreted reporter protein was determined in aliquots of cell culture supernatants. The assay is based on plasminogen activation by low-M(r) u-PA and subsequent cleavage of the plasmin-specific tripeptide substrate, S-2251. The resulting chromophore, p-nitroanilide, was quantified colorimetrically at 405 nm. Transient and stable expression of the low-M(r) u-PA reporter gene in different eukaryotic cells demonstrates the suitability of the system for the quantification of the activity of eukaryotic promoter elements in a rapid and highly sensitive manner, while maintaining cell integrity. PMID:7665095

Langer, G; Toschi, L; Dieckmann, J; Schleuning, W D

1995-08-19

174

PCR/RFLP-based allelic variants of streptokinase and their plasminogen activation potencies.  

Science.gov (United States)

PCR-restriction fragment length polymorphism (PCR/RFLP)-based analysis of ?-domain variable region of streptokinase genes (sk) has previously identified 14 sk alleles (sk1-sk14) in group A (GAS), C (GCS) and G (GGS) streptococci isolates from a few geographically distinct regions. However, the relation of sk allelic variants to their plasminogen activation potencies remained as a matter of debate. Herein, employing the same PCR/RFLP assay, we analysed sk allelic variants of GAS and GCS/GGS isolates from Iranian patients. In total, 21 sk allelic variants including 14 new alleles (sk14-sk28) were identified. Results implied the horizontal gene transfer of sk fragments between GAS and GCS/GGS strains and did not prove the specificity of particular sk alleles to GCS/GGS or GAS groups. Measurement of streptokinase (SK) activity in streptococcal culture supernatants by colorimetric assay (S2251 substrate) ranged from 9 to 182 IU mL(-1). Although some strains with the highest SK activity were detected in definite variants, no significant correlation between sk alleles and plasminogen activation was detected (P value > 0.05). Analysis of DNA sequences and restriction site mapping of selective sk variants with similar SK activity pointed to the inadequacy of the currently available PCR/RFLP method for differentiation of critical/silent nucleotides to precisely categorize sk alleles for their functional properties. PMID:22812485

Keramati, Malihe; Roohvand, Farzin; Eslaminejad, Zahra; Mirzaie, Amir; Nikbin, Vajihe Sadat; Aslani, Mohammad Mehdi

2012-08-29

175

PCR/RFLP-based allelic variants of streptokinase and their plasminogen activation potencies.  

UK PubMed Central (United Kingdom)

PCR-restriction fragment length polymorphism (PCR/RFLP)-based analysis of ?-domain variable region of streptokinase genes (sk) has previously identified 14 sk alleles (sk1-sk14) in group A (GAS), C (GCS) and G (GGS) streptococci isolates from a few geographically distinct regions. However, the relation of sk allelic variants to their plasminogen activation potencies remained as a matter of debate. Herein, employing the same PCR/RFLP assay, we analysed sk allelic variants of GAS and GCS/GGS isolates from Iranian patients. In total, 21 sk allelic variants including 14 new alleles (sk14-sk28) were identified. Results implied the horizontal gene transfer of sk fragments between GAS and GCS/GGS strains and did not prove the specificity of particular sk alleles to GCS/GGS or GAS groups. Measurement of streptokinase (SK) activity in streptococcal culture supernatants by colorimetric assay (S2251 substrate) ranged from 9 to 182 IU mL(-1). Although some strains with the highest SK activity were detected in definite variants, no significant correlation between sk alleles and plasminogen activation was detected (P value > 0.05). Analysis of DNA sequences and restriction site mapping of selective sk variants with similar SK activity pointed to the inadequacy of the currently available PCR/RFLP method for differentiation of critical/silent nucleotides to precisely categorize sk alleles for their functional properties.

Keramati M; Roohvand F; Eslaminejad Z; Mirzaie A; Nikbin VS; Aslani MM

2012-10-01

176

Oropharyngeal angioneurotic edema due to recombinant tissue plasminogen activator following massive pulmonary thromboembolism.  

UK PubMed Central (United Kingdom)

Although hypersensitivity reactions secondary to recombinant tissue plasminogen activator (rtPA) are rarely encountered, they may have important consequences. In this case presentation, oropharyngeal angioneurotic edema due to rtPA following pulmonary thromboembolism is presented. On the 4th hour of initiation of treatment, throat pain, laryngeal stridor and expansive edema in the neck ensued, upon which the patient was intubated and mechanically ventilated. The patient was extubated after her findings showed a remission on the 48th hour of his inotropic, antihistaminic and intravenous corticosteroid therapy.

Ekmekçi P; Bengisun ZK; Kazbek BK; Akmansu H; Beriat GK; Süer AH

2011-09-01

177

[Treatment of pulmonary thromboembolism with extrinsic plasminogen activator. A case report  

UK PubMed Central (United Kingdom)

A 49 year-old woman with acute pulmonary thromboembolism and severe hemodynamic impairment was successfully treated with tissue-type plasminogen activator (r-TPA). She did not have previous pulmonary or cardiac diseases. Thirty days after immobilization of the right ankle, she had a sudden onset of dyspnea, epigastrial pain and syncope. As heparin therapy was unsuccessful, 90 mg of IV r-TPA was administered. There was rapid clinical and hemodynamic improvement of her condition. Pulmonary scanning one week later was normal and she was discharged without symptoms 12 days after the acute episode.

Silva LA; Ribeiro E; Torossian SP; Oliveira JL; Salvadori RA; Petrizzo A; Papa ED; Aboud E; Duprat Filho R

1989-09-01

178

[Treatment of pulmonary thromboembolism with extrinsic plasminogen activator. A case report].  

Science.gov (United States)

A 49 year-old woman with acute pulmonary thromboembolism and severe hemodynamic impairment was successfully treated with tissue-type plasminogen activator (r-TPA). She did not have previous pulmonary or cardiac diseases. Thirty days after immobilization of the right ankle, she had a sudden onset of dyspnea, epigastrial pain and syncope. As heparin therapy was unsuccessful, 90 mg of IV r-TPA was administered. There was rapid clinical and hemodynamic improvement of her condition. Pulmonary scanning one week later was normal and she was discharged without symptoms 12 days after the acute episode. PMID:2517012

Silva, L A; Ribeiro, E; Torossian, S P; Oliveira, J L; Salvadori, R A; Petrizzo, A; Papa, E D; Aboud, E; Duprat Filho, R

1989-09-01

179

Ovine rotaviruses  

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Full Text Available Rotavirus has been recognized as a predominant cause of acute diarrhea in young animals and humans. Rotavirus has segmented genome composed of 11 segments of double stranded RNA. The virus has a triple layered protein shell consisting of a core, an inner capsid and an outer capsid. The inner capsid protein is responsible for group specificity and based on it rotaviruses are classified into seven groups. Ovine rotavirus strains have only been identified into two serogroups (A and B). The two outer capsid proteins (VP7 and VP4) are responsible for G and P typing of rotavirus, respectively. Although rotavirus has been frequently reported in many animal species, data regarding ovine rotavirus strains is very scanty and limited. Only a few ovine rotaviruses have been isolated and characterized so far. Recently, the G and P types circulating in ovines have been identified. The ovine rotavirus strain NT isolated from a diarrheic lamb in China is being considered as a promising vaccine candidate for human infants.

S. Gazal; I.A. Mir; A. Iqbal; A.K. Taku; B. Kumar; M.A. Bhat

2011-01-01

180

Regulation of plasminogen activator activity and expression by cyclic mechanical stress in rat mandibular condylar chondrocytes.  

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To investigate the mechanism of cartilage degradation induced by overloading in the temporomandibular joint (TMJ), the effect of cyclic mechanical compressive stress on the activity of plasminogen activator (PA) and the expression of the predominant components of the PA system were analyzed in cultured mandibular condylar chondrocytes (MCCs) in rats. MCCs were exposed to cyclic mechanical compressive stress (2000, 4000 and 6000 µ strain) at 0.5 Hz by a four?point bending system. The activity of PA was determined by hydrolysis of the chromogenic substrate H?D-Val-Leu-Lys?pNA (S?2251). The mRNA and protein expression levels of urokinase?type PA (uPA), tissue?type PA (tPA), uPA receptor (uPAR) and PA inhibitor 1 (PAI?1) were detected by qPCR and western blot analysis, respectively. Cyclic mechanical stress at 4000 and 6000 µ strain induced the expression of uPA, tPA and uPAR, and increased the activity of PA. Furthermore, cyclic mechanical stress at 6000 µ strain also inhibited the expression of PAI?1. Analysis of pericellular proteolytic activity demonstrated that PA functioned as the active enzyme in excessive mechanical stress responsiveness (e.g., 4000 and 6000 µ strain) largely via uPAR, not PAI?1. Cyclic mechanical stress at 2000 µ strain induced the expression of tPA and PAI?1; however, it did not change the activity of PA. These results suggested that the mechanical induction of uPA, tPA and uPAR upregulated PA activity, which may provide a proteolytic environment of extracellular matrix components and subsequently contribute to the cartilage degradation in TMJ osteoarthritis. PMID:23982192

Chen, Wei; Tang, Yaling; Zheng, Min; Jiang, Jian; Zhu, Guiquan; Liang, Xinhua; Li, Mingzhe

2013-08-27

 
 
 
 
181

alpha Domain deletion converts streptokinase into a fibrin-dependent plasminogen activator through mechanisms akin to staphylokinase and tissue plasminogen activator.  

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The mechanism of action of plasminogen (Pg) activators may affect their therapeutic properties in humans. Streptokinase (SK) is a robust Pg activator in physiologic fluids in the absence of fibrin. Deletion of a "catalytic switch" (SK residues 1-59), alters the conformation of the SK alpha domain and converts SKDelta59 into a fibrin-dependent Pg activator through unknown mechanisms. We show that the SK alpha domain binds avidly to the Pg kringle domains that maintain Glu-Pg in a tightly folded conformation. By virtue of deletion of SK residues 1-59, SKDelta59 loses the ability to unfold Glu-Pg during complex formation and becomes incapable of nonproteolytic active site formation. In this manner, SKDelta59 behaves more like staphylokinase than like SK; it requires plasmin to form a functional activator complex, and in this complex SKDelta59 does not protect plasmin from inhibition by alpha(2)-antiplasmin. At the same time, SKDelta59 is unlike staphylokinase or SK and is more like tissue Pg activator, because it is a poor activator of the tightly folded form of Glu-Pg in physiologic solutions. SKDelta59 can only activate Glu-Pg when it was unfolded by fibrin interactions or by Cl(-)-deficient buffers. Taken together, these studies indicate that an intact alpha domain confers on SK the ability to nonproteolytically activate Glu-Pg, to unfold and process Glu-Pg substrate in physiologic solutions, and to alter the substrate-inhibitor interactions of plasmin in the activator complex. The loss of an intact alpha domain makes SKDelta59 activate Pg through classical "fibrin-dependent mechanisms" (akin to both staphylokinase and tissue Pg activator) that include: 1) a marked preference for a fibrin-bound or unfolded Glu-Pg substrate, 2) a requirement for plasmin in the activator complex, and 3) the creation of an activator complex with plasmin that is readily inhibited by alpha(2)-antiplasmin. PMID:15069059

Sazonova, Irina Y; Robinson, Brian R; Gladysheva, Inna P; Castellino, Francis J; Reed, Guy L

2004-04-06

182

The conversion of active to latent plasminogen activator inhibitor-1 is an energetically silent event.  

Science.gov (United States)

PAI-1 is a proteinase inhibitor, which plays a key role in the regulation of fibrinolysis. It belongs to the serpins, a family of proteins that behave either as proteinase inhibitors or proteinase substrates, both reactions involving limited proteolysis of the reactive center loop and insertion of part of this loop into beta-sheet A. Titration calorimetry shows that the inhibition of tissue-type plasminogen and pancreatic trypsin are exothermic reactions with DeltaH = -20.3, and -22.5 kcal.mol(-1), respectively. The Pseudomonas aeruginosa elastase-catalyzed reactive center loop cleavage and inactivation of the inhibitor is also exothermic (DeltaH = -38.9 kcal.mol(-1)). The bacterial elastase also hydrolyses peptide-bound PAI-1 in which acetyl-TVASSSTA, the octapeptide corresponding to the P(14)-P(7) sequence of the reactive center loop is inserted into beta-sheet A of the serpin with DeltaH = -4.0 kcal.mol(-1). In contrast, DeltaH = 0 for the spontaneous conversion of the metastable active PAI-1 molecule into its thermodynamically stable inactive (latent) conformer although this conversion also involves loop/sheet insertion. We conclude that the active to latent transition of PAI-1 is an entirely entropy-driven phenomenon. PMID:15653733

Boudier, Christian; Gils, Ann; Declerck, Paul J; Bieth, Joseph G

2005-01-14

183

The conversion of active to latent plasminogen activator inhibitor-1 is an energetically silent event.  

UK PubMed Central (United Kingdom)

PAI-1 is a proteinase inhibitor, which plays a key role in the regulation of fibrinolysis. It belongs to the serpins, a family of proteins that behave either as proteinase inhibitors or proteinase substrates, both reactions involving limited proteolysis of the reactive center loop and insertion of part of this loop into beta-sheet A. Titration calorimetry shows that the inhibition of tissue-type plasminogen and pancreatic trypsin are exothermic reactions with DeltaH = -20.3, and -22.5 kcal.mol(-1), respectively. The Pseudomonas aeruginosa elastase-catalyzed reactive center loop cleavage and inactivation of the inhibitor is also exothermic (DeltaH = -38.9 kcal.mol(-1)). The bacterial elastase also hydrolyses peptide-bound PAI-1 in which acetyl-TVASSSTA, the octapeptide corresponding to the P(14)-P(7) sequence of the reactive center loop is inserted into beta-sheet A of the serpin with DeltaH = -4.0 kcal.mol(-1). In contrast, DeltaH = 0 for the spontaneous conversion of the metastable active PAI-1 molecule into its thermodynamically stable inactive (latent) conformer although this conversion also involves loop/sheet insertion. We conclude that the active to latent transition of PAI-1 is an entirely entropy-driven phenomenon.

Boudier C; Gils A; Declerck PJ; Bieth JG

2005-04-01

184

Activation of the zymogen to urokinase-type plasminogen activator is associated with increased interdomain flexibility  

DEFF Research Database (Denmark)

A key regulatory step for serine proteases of the trypsin clan is activation of the initially secreted zymogens, leading to an increase in activity by orders of magnitude. Zymogen activation occurs by cleavage of a single peptide bond near the N-terminus of the catalytic domain. Besides the catalytic domain, most serine proteases have N-terminal A-chains with independently folded domains. Little is known about how zymogen activation affects the interplay between domains. This question is investigated with urokinase-type plasminogen activator (uPA), which has an epidermal growth factor domain and a kringle domain, connected to the catalytic domain by a 15-residue linker. uPA has been implicated under several pathological conditions, and one possibility for pharmacological control is targeting the conversion of the zymogen pro-uPA to active uPA. Therefore, a small-angle X-ray scattering study of the conformations of pro-uPA and uPA in solution was performed. Structural models for the proteins were derived usingavailable atomic-resolution structures for the various domains. Active uPA was found to be flexible with a random conformation of the amino-terminal fragment domain with respect to the serine protease domain. In contrast, pro-uPA was observed to be rigid, with the amino-terminal fragment domain in a fixed position with respect to the serine protease domain. Analytical ultracentrifugation analysis supported the observed difference between pro-uPA and uPA in overall shape and size seen with small-angle X-ray scattering. Upon association of either of two monoclonal Fab (fragment antigen-binding) fragments that are directed against the catalytic domain of, respectively, pro-uPA and uPA, rigid structures were formed

Behrens, Manja A; BØtkjær, Kenneth AlrØ

2011-01-01

185

Cloning and expression of functional full-length human tissue plasminogen activator in Pichia pastoris.  

UK PubMed Central (United Kingdom)

Human tissue plasminogen activator (t-PA) plays a pivotal role in the treatment of acute myocardial infarction, ischemic stroke, and deep vein thrombosis. It has the benefit of generating no adverse effects such as fibrinogen depletion, systemic hemorrhage, and immunologic reactions. Human t-PA is a serine-protease enzyme containing 527 amino acid residues in five structural domains. The correct folding of t-PA requires the correct pairing of 17 disulfide bridges in the molecule. A gene encoding full-length human t-PA was cloned into pPICZ?A expression vector downstream of alcohol oxidase promoter and ?-mating signal sequence from Saccharomyces cerevisiae and flush with the kex2 cleavage site to express the protein with a native N terminus. The methylotrophic yeast, Pichia pastoris GS115 strain, was transformed with this cassette, and methanol utilizing (mut+) transformants were selected for production and secretion of human t-PA into culture media. SDS-PAGE and Western blot analysis showed the expressed bands of t-PA protein. Zymography test indicated suitable folding and proper function of the expressed recombinant human t-PA in conversion of plasminogen to plasmin and gelatin lysis. Amidolytic activity test showed the amidolytic activity of 1,650 IU/ml. The results of this study concluded that P. pastoris methylotrophic yeast can be a suitable alternative for mammalian and prokaryotic expression systems to produce t-PA.

Majidzadeh-A K; Khalaj V; Fatemeh D; Mahdi H; Farzaneh B; Ahmad A; Mahboudi F

2010-11-01

186

Cloning and expression of functional full-length human tissue plasminogen activator in Pichia pastoris.  

Science.gov (United States)

Human tissue plasminogen activator (t-PA) plays a pivotal role in the treatment of acute myocardial infarction, ischemic stroke, and deep vein thrombosis. It has the benefit of generating no adverse effects such as fibrinogen depletion, systemic hemorrhage, and immunologic reactions. Human t-PA is a serine-protease enzyme containing 527 amino acid residues in five structural domains. The correct folding of t-PA requires the correct pairing of 17 disulfide bridges in the molecule. A gene encoding full-length human t-PA was cloned into pPICZ?A expression vector downstream of alcohol oxidase promoter and ?-mating signal sequence from Saccharomyces cerevisiae and flush with the kex2 cleavage site to express the protein with a native N terminus. The methylotrophic yeast, Pichia pastoris GS115 strain, was transformed with this cassette, and methanol utilizing (mut+) transformants were selected for production and secretion of human t-PA into culture media. SDS-PAGE and Western blot analysis showed the expressed bands of t-PA protein. Zymography test indicated suitable folding and proper function of the expressed recombinant human t-PA in conversion of plasminogen to plasmin and gelatin lysis. Amidolytic activity test showed the amidolytic activity of 1,650 IU/ml. The results of this study concluded that P. pastoris methylotrophic yeast can be a suitable alternative for mammalian and prokaryotic expression systems to produce t-PA. PMID:20455033

Majidzadeh-A, Keivan; Khalaj, Vahid; Fatemeh, Davami; Mahdi, Hemayatkar; Farzaneh, Barkhordari; Ahmad, Adeli; Mahboudi, Fereidoun

2010-05-09

187

Serum-stable RNA aptamers to urokinase-type plasminogen activator blocking receptor binding  

DEFF Research Database (Denmark)

The serine proteinase urokinase-type plasminogen activator (uPA) is widely recognized as a potential target for anticancer therapy. Its association with cell surfaces through the uPA receptor (uPAR) is central to its function and plays an important role in cancer invasion and metastasis. In the current study, we used systematic evolution of ligands by exponential enrichment (SELEX) to select serum-stable 2'-fluoro-pyrimidine-modified RNA aptamers specifically targeting human uPA and blocking the interaction to its receptor at low nanomolar concentrations. In agreement with the inhibitory function of the aptamers, binding was found to be dependent on the presence of the growth factor domain of uPA, which mediates uPAR binding. One of the most potent uPA aptamers, upanap-12, was analyzed in more detail and could be reduced significantly in size without severe loss of its inhibitory activity. Finally, we show that the uPA-scavenging effect of the aptamers can reduce uPAR-dependent endocytosis of the uPA-PAI-1 complex and cell-surface associated plasminogen activation in cell culture experiments. uPA-scavenging 2'-fluoro-pyrimidine-modified RNA aptamers represent a novel promising principle for interfering with the pathological functions of the uPA system.

Dupont, Daniel Miotto; Madsen, Jeppe Buur

2010-01-01

188

Urokinase-type plasminogen activator enhances invasion of human T cells (Jurkat) into a fibrin matrix.  

Science.gov (United States)

The receptor for urokinase-type plasminogen activator (uPA-R) localizes uPA to the cell surface. The receptor-bound uPA converts plasminogen to the trypsin-like endopeptidase plasmin. Thus uPA is involved in the initiation of pericellular proteolysis. Pericellular proteolysis is assumed to facilitate the cellular infiltration into surrounding tissue. The uPA-R has recently been identified as a surface antigen of activated human T lymphocytes. We have characterized the uPA-R of the human CD4 T cell line Jurkat by immunological (flow cytometry), biochemical (ligand blotting), and physico-chemical (Scatchard blotting) methods. The collective data suggest that the human CD4+ T cell line Jurkat expresses a cell surface receptor for uPA similar to that of myelo/monocytes and normal T cells with regard to size, affinity, ligand specificity, and antigenicity. Binding studies using exogenous uPA and subsequent functional assays revealed that receptor-bound uPA retains its enzymatic activity. Saturation of the Jurkat cell uPA-R with exogenous uPA facilitated cellular invasion into fibrin matrices in vitro. uPA-dependent invasion was inhibited in the presence of an anti-catalytic monoclonal anti-uPA antibody. We propose that uPA-R-bound uPA may facilitate the invasiveness of uPA-R-positive T lymphocytes. PMID:7915295

Kramer, M D; Spring, H; Todd, R F; Vettel, U

1994-08-01

189

Plasminogen activator inhibitor-1 polymers, induced by inactivating amphipathic organochemical ligands.  

DEFF Research Database (Denmark)

Negatively charged organochemical inactivators of the anti-proteolytic activity of plasminogen activator inhibitor-1 (PAI-1) convert it to inactive polymers. As investigated by native gel electrophoresis, the size of the PAI-1 polymers ranged from dimers to multimers of more than 20 units. As compared with native PAI-1, the polymers exhibited an increased resistance to temperature-induced unfolding. Polymerization was associated with specific changes in patterns of digestion with non-target proteases. During incubation with urokinase-type plasminogen activator, the polymers were slowly converted to reactive centre-cleaved monomers, indicating substrate behaviour of the terminal PAI-1 molecules in the polymers. A quadruple mutant of PAI-1 with a retarded rate of latency transition also had a retarded rate of polymerization. Studying a number of serpins by native gel electrophoresis, ligand-induced polymerization was observed only with PAI-1 and heparin cofactor II, which were also able to copolymerize. On the basis of these results, we suggest that the binding of ligands in a specific region of PAI-1 leads to so-called loop-sheet polymerization, in which the reactive centre loop of one molecule binds to beta-sheet A in another molecule. Induction of serpin polymerization by small organochemical ligands is a novel finding and is of protein chemical interest in relation to pathological protein polymerization in general. Udgivelsesdato: 2003-Jun-15

Pedersen, Katrine E; Einholm, Anja P

2003-01-01

190

Plasminogen activator inhibitor-1 levels and activity decrease after intervention in patients with critical limb ischaemia.  

UK PubMed Central (United Kingdom)

OBJECTIVE/BACKGROUND: Patients with peripheral arterial occlusive disease (PAOD), in particular critical limb ischaemia (CLI), carry a high risk of thrombotic events. We hypothesised that patients undergoing conservative, endovascular, or open surgical treatment for CLI have increased levels of plasminogen activator inhibitor-1 (PAI-1), leading to a prothrombotic state. The objective was to determine levels of PAI-1 in patients with acute or chronic PAOD/CLI. METHODS: Thirty-two patients with a median age of 74 (49-90) years were included. Three underwent thrombolysis for acute limb-threatening ischaemia. Twenty-six patients with chronic ischaemia received endovascular (n = 20) or open (n = 6) surgical treatment. Three were treated conservatively. Biomarkers and ankle brachial index (ABI) were measured before and up to 1 month after intervention. Patency was studied with repeated duplex ultrasound. RESULTS: Ankle pressure and ABI improved after intervention (p < .001). C-reactive protein (CRP) increased from a median of 7.90 mg/L at baseline to 31.5 on day 1 (p < .001), 28.0 on day 6 (p < .001), and returned to baseline levels on day 30. PAI-1 antigen and activity decreased from day 6 and onwards post-intervention compared with baseline (p < .05). A great individual variability in PAI-1 antigen and activity was observed. Although most actively treated patients had normal PAI-1 activity, 11/29 (38%) were above that level of normality at baseline, 10/24 (42%) on day 1, 3/23 (13%) on day 6, and 5/27 (19%) on day 30 after intervention. CONCLUSION: Endovascular and open surgical treatment resulted in improved ankle pressure and ABI. The intervention was followed by a transient increase in CRP and a sustained reduction in PAI-1 levels and activity.

Björck M; Lepkowska Eriksson M; Bylock A; Steuer J; Wanhainen A; Carlsson BC; Bock D; Kragsterman B

2013-08-01

191

Chromogenic assay for equine plasminogen.  

UK PubMed Central (United Kingdom)

A functional assay for equine plasminogen was established, using urokinase as the activator, a synthetic chromogenic substrate, a computer-assisted centrifugal analyzer, and acidified/neutralized plasma. One documented effect of plasma acidification appears to be inactivation of alpha-2-antiplasmin. Intra- and interassay precision testing yielded coefficients of variation of 4.1% (n = 10) and 5.6% (n = 26), respectively. Plasminogen was stable in equine plasma stored up to 1 week at 4 C and up to 5 months at -70 C. Plasminogen in nonacidified equine plasma was not activated by urokinase, streptokinase, tissue plasminogen activator, or tissue plasminogen activator plus soluble fibrin. Streptokinase also failed to activate plasminogen in acidified/neutralized equine plasma.

Welles EG; Prasse KW; Duncan A

1990-07-01

192

Targeting the autolysis loop of urokinase-type plasminogen activator with conformation-specific monoclonal antibodies  

DEFF Research Database (Denmark)

Tight regulation of serine proteases is essential for their physiological function, and unbalanced states of protease activity have been implicated in a variety of human diseases. One key example is the presence of uPA (urokinase-type plasminogen activator) in different human cancer types, with high levels correlating with a poor prognosis. This observation has stimulated efforts into finding new principles for intervening with uPA's activity. In the present study we characterize the so-called autolysis loop in the catalytic domain of uPA as a potential inhibitory target. This loop was found to harbour the epitopes for three conformation-specific monoclonal antibodies, two with a preference for the zymogen form pro-uPA, and one with a preference for active uPA. All three antibodies were shown to have overlapping epitopes, with three common residues being crucial for all three antibodies, demonstrating a direct link between conformational changes of the autolysis loop and the creation of a catalytically matureactive site. All three antibodies are potent inhibitors of uPA activity, the two pro-uPA-specific ones by inhibiting conversion of pro-uPA to active uPA and the active uPA-specific antibody by shielding the access of plasminogen to the active site. Furthermore, using immunofluorescence, the conformation-specific antibodies mAb-112 and mAb-12E6B10 enabled us to selectively stain pro-uPA or active uPA on the surface of cultured cells. Moreover, in various independent model systems, the antibodies inhibited tumour cell invasion and dissemination, providing evidence for the feasibility of pharmaceutical intervention with serine protease activity by targeting surface loops that undergo conformational changes during zymogen activation.

BØtkjær, Kenneth AlrØ; Fogh, Sarah

2011-01-01

193

Detection of deep venous thrombosis with indium 111-labelled monoclonal antibody against tissue plasminogen activator  

International Nuclear Information System (INIS)

The administration of a radiolabelled monoclonal antibody against tissue plasminogen activator allows detection of areas with increased fibrinolytic activity, i.e. those with an active thrombotic lesion. Eight patients with phlebographically verified deep venous thrombosis were examined. At the time of immunoscintigraphy study they were examined receiving anticoagulant therapy. Some 75-85 MBq 111In-labelled antibody were injected, and scintigrams were obtained after 30 min and after 24 h. The precise site of the thrombus could not be visualized after 30 min due to high background activity, whereas after 24 h it was detectable in all patients. The thrombus/background ratios achieved are twice as high as those observed in a human antifibrin antibody study. These preliminary data suggest a high sensitivity of our PA-specific antibody for the detection of active deep venous thrombosis in man, and our antibody seems to offer theoretical advantages over both platelet and fibrin-specific antibodies. (orig.)

1991-01-01

194

Cleaved intracellular plasminogen activator inhibitor 2 in human myeloleukaemia cells is a marker of apoptosis  

DEFF Research Database (Denmark)

The proteolytic modification of plasminogen activator inhibitor 2 (PAI-2) was studied during apoptosis in the human promyelocytic leukaemic NB4 cell line during treatment with the phosphatase inhibitors okadaic acid and calyculin A as well as the protein synthesis inhibitor cycloheximide. The apoptic type of cell death was ascertained by morphological and biochemical criteria. In cell homogenates PAI-2 was probed by [125I]urokinase plasminogen activator (uPA) and detected as a sodium dodecyl sulphate-stable M(r) 80,000 complex after reducing sodium dodecyl sulphate-polyacrylamide gel electrophoresis and autoradiography. During apoptosis a smaller (M(r) 70,000) uPA-PAI-2 complex was consistently detected. The modification was in the PAI-2 moiety, as the [125I]uPA tracer could be extracted in its intact form from the complex. Thus the cleaved PAI-2 isoform is a biochemical marker of apoptosis in the promyelocytic NB4 cell line. The modified PAI-2 isoform was also detected in homogenates made from purified humanmononuclear leukaemic cells aspirated from the bone marrow of patients suffering from acute and chronic myeloid leukaemia.

Jensen, P H; Cressey, L I

1994-01-01

195

Increased expression of urokinase plasminogen activator and its cognate receptor in human seminomas  

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Full Text Available Abstract Background The urokinase plasminogen activating system (uPAS) is implicated in neoplastic progression and high tissue levels of uPAS components correlate with a poor prognosis in different human cancers. Despite that, relative few studies are available on the expression and function of the uPAS components in human seminomas. In the present study we characterized the expression of the urokinase plasminogen activator (uPA), its cognate receptor (uPAR) and the uPA inhibitors PAI-1 and PAI-2 in normal human testis and seminomas. Methods The expression of the above genes was evaluated by means of quantitative RT-PCR, western blot, zymographic analysis and immunohistochemistry. Results Quantitative RT-PCR analysis of 14 seminomas demonstrated that uPA and uPAR mRNAs were, with respect to control tissues, increased in tumor tissues by 3.80 ± 0.74 (p Conclusions We demonstrated the increased expression of uPA and uPAR in human seminomas with respect to normal testis tissues, which may be relevant in testicular cancer progression.

Ulisse Salvatore; Baldini Enke; Mottolese Marcella; Sentinelli Steno; Gargiulo Patrizia; Valentina Brancato; Sorrenti Salvatore; Di Benedetto Anna; De Antoni Enrico; D'Armiento Massimino

2010-01-01

196

Enhanced functional stability of plasminogen activator inhibitor-1 in patients with livedoid vasculopathy.  

UK PubMed Central (United Kingdom)

Livedoid vasculopathy (LV) is a chronic, recurrent, painful cutaneous disease with distinctive clinical features and an uncertain etiology. The skin lesions are recognizable by focal purpura, depigmentation and shallow ulcers. Thrombophilic conditions occur frequently in patients with LV. While no definitive treatment exists for LV, smoking cessation, antiplatelet therapy, immunosuppressive treatment, and anabolic steroids are often included in the therapeutic ladder. Recently, a possible link between LV and impaired fibrinolysis was established as cutaneous LV lesions responded to tissue plasminogen activator (t-PA) infusion suggesting that inhibition of the fibrinolysis through plasminogen activator inhibitor-1 (PAI-1) activity may determine the disease course in patients with LV. In this study, we investigated PAI-1 antigen (Ag) and activity levels in 20 patients with biopsy proven LV (mean age 26 ± 11, M/F = 7/13, median disease duration 3.5 years). All patients received antiplatelet treatment with aspirin and/or dipyrimadole and 14 patients received anabolic steroids or immunosuppressive treatment. Fasting PAI-1 Ag and activity levels were measured at 9 AM in all patients. Both Ag (34 (26) ng/ml) (median (interquartile range)) and specific activity (17 (23) IU/fmole) levels of PAI-1 were moderately elevated in LV patients compared to the controls, however, PAI-1 kinetic studies demonstrated markedly enhanced stability of PAI-1 activity in plasma from patients with LV. Specific activity at 16 h was significantly higher than expected specific activity levels (7 (11) vs. 0.07 (0.09) IU/fmole, P < 0.01). While the exact mechanism of increased stability of PAI-1 activity is not known, it may be due to post-translational modifications or increased binding affinity for a stabilizing cofactor. In conclusion, enhanced stability of PAI-1 may contribute to the pathophysiology of LV, and systemic or local treatment with PAI-1 inhibitors may offer a potential treatment alternative in patients with LV.

Agirbasli M; Eren M; Eren F; Murphy SB; Serdar ZA; Seckin D; Zara T; Cem Mat M; Demirkesen C; Vaughan DE

2011-07-01

197

INDUCTION OF MACROPHAGE PLASMINOGEN ACTIVATOR BY ENDOTOXIN STIMULATION AND PHAGOCYTOSIS : Evidence for A Two-Stage Process  

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The injection of thioglycollate medium into the peritoneal cavity of the mouse induces high levels of macrophage fibrinolytic activity due to the production and secretion of a plasminogen activator, a trypsinlike serine protease, which is absent in unstimulated macrophages. Intraperitoneal injectio...

Gordon, Saimon; Unkeless, Ay C.; Cohn, Z. A.

198

Long-term stability of recombinant tissue plasminogen activator at -80 C  

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Full Text Available Abstract Background Recombinant tissue plasminogen activator (tPA) is a thrombolytic widely used clinically in the treatment of acute thrombotic disease such as ischemic stroke, myocardial infarction, and deep venous thrombosis. This has led to much interest in tPA based lytic therapies leading to laboratory based in-vitro and in-vivo investigations using this drug. However, tPA reconstituted in solution exhibits full activity for only 6–8 hours, according to the manufacturer. Therefore, methods to store reconstituted tPA for long durations while maintaining activity would be of assistance to laboratories using this enzyme. Findings In this work, the enzymatic activity of tPA stored at -80 C over time was measured, using an ELISA technique that measured the amount of active tPA bound to plasminogen activator inhibitor 1 (PAI-1) in a given sample. Sample of tPA solution mixed to a concentration of 1 (mg/ml) were stored in cryogenic vials at -80 C for up to 7 years. For a given sample, aliquots were assayed for tPA activity, and compared with a tPA standard to determine relative enzymatic activity. Results are reported as means with standard errors, and 12 measurements were performed for each sample age. Conclusion There was no decrease in tPA activity for samples stored up to 7 years. Such cryogenic storage is a viable method for the preservation of tPA solution for laboratory investigations of tPA-based lytic therapies.

Shaw George J; Sperling Matthew; Meunier Jason M

2009-01-01

199

The contact-system dependent plasminogen activator from human plasma: identification and characterization.  

UK PubMed Central (United Kingdom)

Apart from tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA), a third PA appears to occur in human plasma. Its activity is initiated when appropriate triggers of the contact system are added, and the activation depends on the presence of factor XII and prekallikrein in plasma. The activity of this, so-called, contact-system dependent PA accounts for 30% of the PA activity in the dextran sulphate euglobulin fraction of plasma and was shown not to be an intrinsic property of one of the contact-system components, nor could it be inhibited by inhibitory antibodies against t-PA or u-PA. We have succeeded in identifying this third PA in dextran sulphate euglobulin fractions of human plasma. Its smallest unit (SDS-PAGE) is an inactive 110 kDa single-chain polypeptide which upon activation of the contact system is converted to a cleaved, disulphide-bridged molecule with PA activity. The native form, presumably, is an oligomer, since the apparent Mr on gel-chromatography is 600,000. The IEP is 4.8, much lower than that of t-PA and u-PA. Although the active 110 kDa polypeptide cannot be inhibited by anti-u-PA, it yet comprises a 37 kDa piece with some u-PA related antigenic determinants. However, these determinants are in a latent or cryptic form, only detectable after denaturation by SDS. The 110 kDa polypeptide is evidently not a dimer of 55 kDa u-PA or a complex of u-PA with an inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Binnema DJ; Dooijewaard G; van Iersel JJ; Turion PN; Kluft C

1990-11-01

200

The contact-system dependent plasminogen activator from human plasma: identification and characterization.  

Science.gov (United States)

Apart from tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA), a third PA appears to occur in human plasma. Its activity is initiated when appropriate triggers of the contact system are added, and the activation depends on the presence of factor XII and prekallikrein in plasma. The activity of this, so-called, contact-system dependent PA accounts for 30% of the PA activity in the dextran sulphate euglobulin fraction of plasma and was shown not to be an intrinsic property of one of the contact-system components, nor could it be inhibited by inhibitory antibodies against t-PA or u-PA. We have succeeded in identifying this third PA in dextran sulphate euglobulin fractions of human plasma. Its smallest unit (SDS-PAGE) is an inactive 110 kDa single-chain polypeptide which upon activation of the contact system is converted to a cleaved, disulphide-bridged molecule with PA activity. The native form, presumably, is an oligomer, since the apparent Mr on gel-chromatography is 600,000. The IEP is 4.8, much lower than that of t-PA and u-PA. Although the active 110 kDa polypeptide cannot be inhibited by anti-u-PA, it yet comprises a 37 kDa piece with some u-PA related antigenic determinants. However, these determinants are in a latent or cryptic form, only detectable after denaturation by SDS. The 110 kDa polypeptide is evidently not a dimer of 55 kDa u-PA or a complex of u-PA with an inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2128968

Binnema, D J; Dooijewaard, G; van Iersel, J J; Turion, P N; Kluft, C

1990-11-30

 
 
 
 
201

Stability of Recombinant Tissue Plasminogen Activator at ?30 °C over One Year  

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Full Text Available Recombinant tissue plasminogen activator (rt-PA) is used to restore patency and avoid inadvertent removal of peripheral and central venous catheters. rt-PA was reconstituted (1 mg/mL) then cryopreserved at ?30 °C for 1, 2, 3, 6, 8, and 12 months and, then its stability was determined. After cryopreservation for one and two months, rt-PA kept more than 95% of its activity compared to standard samples, while cryopreservation for three months caused 8% loss of activity. However, after cryopreservation for six months or more, rt-PA retained only 87.5% or less activity compared to standard samples. Therefore, it is recommended that reconstituted rt-PA be cryopreserved at ?30 °C for a maximum period of three months.

Abdulmalik Alkatheri

2013-01-01

202

Clinical significance of plasminogen activator inhibitor activity in patients with exercise-induced ischemia  

Energy Technology Data Exchange (ETDEWEB)

To assess the fibrinolytic system in patients with exercise-induced ischemia and its relation to ischemia and severity of coronary artery disease (CAD), 47 patients with CAD confirmed by results of coronary angiography underwent symptom-limited multistage exercise thallium-201 emission computed tomography. All patients with CAD had exercise-induced ischemia as assessed from thallium-201 images. Pre- and peak exercise blood samples from each patient and preexercise blood samples from control subjects were assayed for several fibrinolytic components and were also assayed for plasma adrenaline. The extent of ischemia was defined as delta visual uptake score (total visual uptake score in delayed images minus total visual uptake score in initial images) and the severity of CAD as the number of diseased vessels. In the basal condition, plasminogen activator inhibitor (PAI) activity was significantly higher in patients with exercise-induced ischemia as compared to control subjects (p less than 0.01), although there were no significant differences in other fibrinolytic variables between the two groups. Moreover, PAI activity in the basal condition displayed a significantly positive correlation with the extent of ischemia (r = 0.47, p less than 0.01). Patients with exercise-induced ischemia were divided into two groups (24 with single-vessel disease and 23 with multivessel disease). There were no significant differences in coronary risk factors, hemodynamics, or plasma adrenaline levels during exercise between single-vessel and multivessel disease except that delta visual uptake score was significantly higher in multivessel disease (p less than 0.01).

Sakata, K.; Kurata, C.; Taguchi, T.; Suzuki, S.; Kobayashi, A.; Yamazaki, N.; Rydzewski, A.; Takada, Y.; Takada, A. (Hamamatsu Univ. School of Medicine, Shizuoka (Japan))

1990-10-01

203

Downstream targets of urokinase-type plasminogen-activator-mediated signal transduction.  

Science.gov (United States)

We have investigated cellular signalling events induced by urokinase-type plasminogen activator (uPA) independent of its proteolytic activity. Treatment of the human fibrosarcoma cell line HT 1080 with diisopropylphosphorofluoridate-inactivated uPA (Dip-F-uPA) triggers a cascade of intracellular signals which are mediated by the specific cell surface receptor for uPA (uPAR). We have found that anti-uPAR Ig precipitate the src-type protein tyrosine kinases fyn, hck and lck, which belong to a family of structurally and functionally related effectors participating in signalling from antigen and cytokine receptors. Of the three uPAR-associated kinases, only hck is activated by uPA, whereas no changes in the activities of either fyn or lck could be detected by an in vitro immune complex kinase assay. We identified p38 and extracellular-signal-regulated kinase 2 from the mitogen-activated protein kinase family as downstream components of a set of consecutive signalling molecules which teleologically alter the program of gene expression. Exposure of cells to uPA results in a significant increase in c-fos mRNA that is partially due to an elevated rate of gene transcription. Presumably, the activation of the c-fos gene leads to the subsequent formation of the transcription factor activator protein-1 (AP-1), since accumulation of c-fos mRNA is followed by induction of target genes sensitive to AP-1 such as plasminogen activator inhibitor type 2 (PAI-2). These results provide new insights into proteolysis-independent cytokine-like effects of uPA. PMID:9654092

Konakova, M; Hucho, F; Schleuning, W D

1998-04-15

204

Physical exercise induces enhancement of urokinase-type plasminogen activator (u-PA) levels in plasma.  

UK PubMed Central (United Kingdom)

The enhancement of the blood fibrinolytic potential by physical exercise is generally attributed to the release of tissue-type plasminogen activator (t-PA) from the vessel wall. In this study we have investigated the possible contribution of urokinase-type plasminogen activator (u-PA). Six healthy male volunteers (age 21-25 years) were screened for their ability to perform maximal exercise for their age-group for 12 min on a bicycle ergometer. Subsequently, on one occasion they were required to remain supine for 2 h (from 8.30 a.m. onwards) an on another they performed maximal exercise (from 9.00 a.m. onwards). During exercise an increase in u-PA antigen and plasmin-activatable pro-urokinase (proUK) activity, concurrent with t-PA antigen and euglobulin t-PA activity, was observed in all six volunteers, while at rest these parameters remained unaffected. Mean u-PA- and t-PA antigen increased, respectively, from 4.2 +/- 1.0 ng/ml and 5.8 +/- 2.1 ng/ml before exercise to 9.8 +/- 3.0 ng/ml and 18.3 +/- 3.8 ng/ml (peak). Mean plasmin-activatable proUK activity and t-PA activity increased, respectively, from 2.1 +/- 0.4 ng/ml and 0.3 +/- 0.2 ng/ml before exercise to 4.3 +/- 1.7 ng/ml and 7.2 +/- 4.0 ng/ml (peak). The increases were statistically significant throughout (paired t-test, pre vs post, antigen P less than 0.005 and activity P less than 0.02). After cessation of exercise u-PA and t-PA declined concurrently to normal values with a 50% decay in about 5 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Dooijewaard G; de Boer A; Turion PN; Cohen AF; Breimer DD; Kluft C

1991-01-01

205

Physical exercise induces enhancement of urokinase-type plasminogen activator (u-PA) levels in plasma.  

Science.gov (United States)

The enhancement of the blood fibrinolytic potential by physical exercise is generally attributed to the release of tissue-type plasminogen activator (t-PA) from the vessel wall. In this study we have investigated the possible contribution of urokinase-type plasminogen activator (u-PA). Six healthy male volunteers (age 21-25 years) were screened for their ability to perform maximal exercise for their age-group for 12 min on a bicycle ergometer. Subsequently, on one occasion they were required to remain supine for 2 h (from 8.30 a.m. onwards) an on another they performed maximal exercise (from 9.00 a.m. onwards). During exercise an increase in u-PA antigen and plasmin-activatable pro-urokinase (proUK) activity, concurrent with t-PA antigen and euglobulin t-PA activity, was observed in all six volunteers, while at rest these parameters remained unaffected. Mean u-PA- and t-PA antigen increased, respectively, from 4.2 +/- 1.0 ng/ml and 5.8 +/- 2.1 ng/ml before exercise to 9.8 +/- 3.0 ng/ml and 18.3 +/- 3.8 ng/ml (peak). Mean plasmin-activatable proUK activity and t-PA activity increased, respectively, from 2.1 +/- 0.4 ng/ml and 0.3 +/- 0.2 ng/ml before exercise to 4.3 +/- 1.7 ng/ml and 7.2 +/- 4.0 ng/ml (peak). The increases were statistically significant throughout (paired t-test, pre vs post, antigen P less than 0.005 and activity P less than 0.02). After cessation of exercise u-PA and t-PA declined concurrently to normal values with a 50% decay in about 5 min.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1902597

Dooijewaard, G; de Boer, A; Turion, P N; Cohen, A F; Breimer, D D; Kluft, C

1991-01-23

206

Biological and binding activities of ovine and porcine prolactins in porcine mammary tissue  

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The concentration of prolactin receptors may play a critical role in regulating growth and development of the mammary gland during gestation and tumor development; however, the discrepancy between specific binding of ovine prolactin (oPRL) and porcine prolactin (pPRL) in porcine mammary tissue was disturbing. It was possible that /sup 125/I-oPRL may be an unsuitable ligand for the procine prolactin receptor. The validate the use of oPRL in binding assays, the biological and binding activities of oPRL and pPRL were compared. A lactogenic bioassay of pPRL was developed using porcine mammary explants cultured in Medium 199 containing insulin, cortisol, and pPRL. The potencies of oPRL and pPRL were compared using this bioassay. Oxidation of glucose and incorporation of glucose into lipids were similarly enhanced by physiological concentrations of both oPRL and pPRL. However, specific binding of /sup 125/I-oPRL was 20%, while less than 1% of /sup 125/I-pPRL was bound. /sup 125/I-oPRL bound to high affinity sites.

Jerry, D.J.

1987-01-01

207

Irsogladine maleate inhibits angiogenesis in wild-type and plasminogen activator-deficient mice.  

UK PubMed Central (United Kingdom)

BACKGROUND: The activation of the zymogen plasminogen to the serine protease plasmin by urokinase-type (uPA) and tissue-type (tPA) plasminogen activators (PA) is an important event in a variety of physiologic and pathophysiologic processes in mammals. Enhanced PA activity occurs during angiogenesis and has been correlated in vitro and in vivo with increased tumor aggressiveness and is an indicator of poor prognosis in a variety of tumors in humans. Preliminary studies suggest that the antiulcer drug irsogladine maleate (IM) diminishes PA activity in vitro and may inhibit angiogenesis in vivo. To define the precise mechanism of angiogenesis inhibition by IM in vivo, we tested the ability of IM to blunt angiogenesis in a mouse cornea neovascularization model performed in wild-type and PA-knockout mice. METHODS: Three days prior to pellet implantation, groups of C57Bl/6 wild-type, uPA-deficient (upA-/-), and tPA-deficient (tPA-/-) mice received IM (300 mg/kg), IM (500 mg/kg), or vehicle (0.5% carboxymethylcellulose) via oral gavage. After 3 days of treatment, hydron polymer-coated pellets of sucrose aluminum sulfate containing 100 ng of basic fibroblast growth factor (bFGF) were inserted into surgically created pockets in the cornea of each mouse. On postoperative day 6, the neovascularization of each cornea was evaluated by a blinded observer using slit lamp microscopy and photographed. Angiogenesis was quantified by calculating vascular area (mm2) +/- SEM using a modified formula for a half ellipse that incorporates calibrated vessel measurements [Vessel length (mm) x Clock hours x pi x 0.2]. RESULTS: IM treatment (300 and 500 mg/kg/day) resulted in a dose-dependent reduction of angiogenesis in wild-type mice by 21 and 45.3% (P < 0.02, P < 0.001), in tPA-deficient mice by 42.6 and 46% (P < 0.001, P < 0.001), and in uPA-deficient mice by 27.2 and 46% (P < 0.05, p < 0.001), respectively. No quantitative differences in neovascularization were observed in either treatment group between transgenic mouse strains. No toxicity was noted in any group. CONCLUSION: IM inhibits bFGF-induced angiogenesis in wild-type, tPA-knockout, and uPA-knockout mice. The observation that IM significantly diminishes angiogenesis in both PA-deficient mice and wild-type mice suggests that the mechanism of action of IM may be independent of plasminogen activation.

Ren CJ; Ueda F; Roses DF; Harris MN; Mignatti P; Rifkin DB; Shapiro RL

1998-07-01

208

Prion protein stimulates tissue-type plasminogen activator-mediated plasmin generation via a lysine-binding site on kringle 2.  

Science.gov (United States)

Recombinant human prion-protein (PrP23-231) stimulates plasminogen activation by tissue-type plasminogen activator (t-PA). The stimulatory activity is conserved in the N-terminal fragment (PrP23-110). It has further been shown by others that PrP(c) binds to kringle-domains of plasminogen. We compared the stimulatory activity of recombinant PrP23-231 and PrP23-110 on plasminogen activation catalyzed by t-PA, urokinase (u-PA), streptokinase and Desmodus salivary plasminogen activator (DSPAalpha1). As these plasminogen activators are distinct, with respect to their kringle domains we studied their binding to immobilized PrP23-110. Plasminogen activation was measured in a chromogenic assay in vitro and binding studies were carried out using surface plasmon resonance technology. We found that recombinant full-length prion protein, PrP23-231, and PrP23-110 specifically stimulate t-PA mediated plasminogen activation. Two hundred nanomoles per liter of PrP23-110 stimulated 1.8 nmol L(-1) t-PA 48-fold, 180 nmol L(-1) DSPA(alpha1) 2.5-fold, 1.8 nmol L(-1) u-PA 1.1-fold, and 1.8 nmol L(-1) streptokinase 1.8-fold. Our data show no specific binding for streptokinase. In contrast all plasminogen activators carrying a kringle domain bound to PrP23-110. We further studied the effect of lysine on binding to PrP23-110 and on plasminogen activation by DSPA(alpha1) or t-PA. Lysine decreased both the binding of t-PA to PrP23-110 and the stimulation of plasmin generation by t-PA. Both binding and plasminogen activation of DSPA(alpha1) were not influenced by the presence of lysine. All plasminogen activators tested bearing kringle domains bind to PrP23-110. Binding to PrP23-110 is not sufficient for stimulation of plasmin generation. Thus the lysine-binding site of kringle 2 that is unique to t-PA appears to mediate the specific stimulation of plasminogen activation by the cellular prion protein. PMID:15140132

Epple, Guido; Schleuning, Wolf-Dieter; Kettelgerdes, Gerhard; Kottgen, Eckart; Gessner, Reinhard; Praus, Michael

2004-06-01

209

Oxidized LDL and lysophosphatidylcholine stimulate plasminogen activator inhibitor-1 expression in vascular smooth muscle cells.  

Science.gov (United States)

Plasminogen activator inhibitor-1 (PAI-1) functions as an important regulator of fibrinolysis by inhibiting both tissue-type and urokinase-type plasminogen activator. PAI-1 is produced by smooth muscle cells (SMCs) in atherosclerotic arteries, but the mechanisms responsible for induction of PAI-1 in SMCs are less well understood. In cultured human aortic SMCs, PAI-1 mRNA expression and protein secretion were increased after incubation with oxidized low-density lipoprotein (LDL) and the lipid peroxidation product lysophosphatidylcholine, whereas the effects of native LDL on PAI-1 production and release were more variable and did not reach statistical significance. The effect of LDL on arterial expression of PAI-1 in vivo was also studied in an animal model. Intravenous injection of human LDL in Sprague-Dawley rats resulted in accumulation of apolipoprotein B in the aorta within 12 hours as assessed by immunohistochemical testing. Epitopes specific for oxidized LDL began to develop in the aorta 12 hours after injection of LDL and peaked at 24 hours; this peak was accompanied by intense expression of PAI-1 immunoreactivity in the media. Also, increased aortic expression of PAI-1 mRNA after LDL injection was detected by using in situ hybridization. The transcription factor activator protein-1, which is known to bind to the promoter of the PAI-1 gene, was activated in the aortic wall 24 hours after LDL injection as assessed by electrophoretic mobility shift assay. Pretreatment of LDL with the antioxidant probucol decreased expression of oxidized LDL and PAI-1 immunoreactivity and activator protein-1 induction in the aorta but did not affect expression of apolipoprotein B immunoreactivity. These findings demonstrate that LDL oxidation enhances secretion of PAI-1 from cultured SMCs and that a similar mechanism may be involved in vascular expression of PAI-1. PMID:10591684

Dichtl, W; Stiko, A; Eriksson, P; Goncalves, I; Calara, F; Banfi, C; Ares, M P; Hamsten, A; Nilsson, J

1999-12-01

210

Oxidized LDL and lysophosphatidylcholine stimulate plasminogen activator inhibitor-1 expression in vascular smooth muscle cells.  

UK PubMed Central (United Kingdom)

Plasminogen activator inhibitor-1 (PAI-1) functions as an important regulator of fibrinolysis by inhibiting both tissue-type and urokinase-type plasminogen activator. PAI-1 is produced by smooth muscle cells (SMCs) in atherosclerotic arteries, but the mechanisms responsible for induction of PAI-1 in SMCs are less well understood. In cultured human aortic SMCs, PAI-1 mRNA expression and protein secretion were increased after incubation with oxidized low-density lipoprotein (LDL) and the lipid peroxidation product lysophosphatidylcholine, whereas the effects of native LDL on PAI-1 production and release were more variable and did not reach statistical significance. The effect of LDL on arterial expression of PAI-1 in vivo was also studied in an animal model. Intravenous injection of human LDL in Sprague-Dawley rats resulted in accumulation of apolipoprotein B in the aorta within 12 hours as assessed by immunohistochemical testing. Epitopes specific for oxidized LDL began to develop in the aorta 12 hours after injection of LDL and peaked at 24 hours; this peak was accompanied by intense expression of PAI-1 immunoreactivity in the media. Also, increased aortic expression of PAI-1 mRNA after LDL injection was detected by using in situ hybridization. The transcription factor activator protein-1, which is known to bind to the promoter of the PAI-1 gene, was activated in the aortic wall 24 hours after LDL injection as assessed by electrophoretic mobility shift assay. Pretreatment of LDL with the antioxidant probucol decreased expression of oxidized LDL and PAI-1 immunoreactivity and activator protein-1 induction in the aorta but did not affect expression of apolipoprotein B immunoreactivity. These findings demonstrate that LDL oxidation enhances secretion of PAI-1 from cultured SMCs and that a similar mechanism may be involved in vascular expression of PAI-1.

Dichtl W; Stiko A; Eriksson P; Goncalves I; Calara F; Banfi C; Ares MP; Hamsten A; Nilsson J

1999-12-01

211

Direct fluorescent assay of urokinase and plasminogen activators of normal and malignant cells: kinetics and inhibitor profiles.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A direct rate assay for plasminogen activator has been developed using a synthetic fluorogenic peptide substrate, 7-(N-Cbz-glycylglycylargininamido)-4-methylcoumarin trifluoroacetate. The assay correlates well with the standard 125I-labeled fibrin plate assay using highly purified urokinase, culture...

Zimmerman, M; Quigley, J P; Ashe, B; Dorn, C; Goldfarb, R; Troll, W

212

Rapid formation of an anion-sensitive active site in stoichiometric complexes of streptokinase and human [Glu1]plasminogen.  

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We have examined the time-dependent appearance of amidolytic activity in equimolar complexes of streptokinase (SK) and human [Glu1]plasminogen (HPg) under various conditions. When stoichiometric levels of the two proteins are incubated and assayed in hypotonic buffers at 4 degrees C, amidolytic acti...

Chibber, B A; Radek, J T; Morris, J P; Castellino, F J

213

Angiotensin II induces plasminogen activator inhibitor-1 and -2 expression in vascular endothelial and smooth muscle cells.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Angiotensin II (AII)- and Arg8-vasopressin (AVP)-regulated gene expression in vascular cells has been reported to contribute to vascular homeostasis and hypertrophy. In this report, AVP-induced expression of plasminogen activator inhibitor (PAI)-2 mRNA in rat microvessel endothelial (RME) cells was ...

Feener, E P; Northrup, J M; Aiello, L P; King, G L

214

Infusion of recombinant human tissue plasminogen activator through the superior mesenteric artery in the treatment of acute mesenteric venous thrombosis.  

UK PubMed Central (United Kingdom)

Acute mesenteric venous thrombosis is an uncommon condition that is usually treated with systemic anticoagulation. Catheter-directed thrombolysis through the superior mesenteric artery may be a viable adjunct to treat this morbid condition. In the present article, we have described a case of superior mesenteric venous thrombosis treated with catheter-directed infusion of tissue plasminogen activator through the superior mesenteric artery.

da Motta Leal Filho JM; Santos AC; Carnevale FC; de Oliveira Sousa W Jr; Grillo LS Jr; Cerri GG

2011-08-01

215

Monoclonal antibodies monospecific to single-chain urokinase-type plasminogen activator (scu-PA).  

Science.gov (United States)

Until now, single-chain urokinase-type plasminogen activator (scu-PA) could not be distinguished from urokinase (UK) by immunological methods. Therefore, in our study monoclonal antibodies (mAbs) specific for scu-PA were raised in mice. These mAbs proved to discriminate between scu-PA, UK and plasmin-activated scu-PA. The clones producing these mAbs could be cultivated in a serum-free medium. Furthermore, very pure preparations were obtained by a one-step purification procedure on protein-A-sepharose. The mAbs described provide a future potential for immuno-affinity chromatography and for the specific determination of scu-PA. PMID:1916850

Scheuerlein, J G; Kalies, I; Gluth, W P; Kalden, J R

1991-06-01

216

Increased expression of the urokinase plasminogen activator system by Helicobacter pylori in gastric epithelial cells  

Science.gov (United States)

The gastric pathogen Helicobacter pylori (H. pylori) is linked to peptic ulcer and gastric cancer, but the relevant pathophysiological mechanisms are unclear. We now report that H. pylori stimulates the expression of plasminogen activator inhibitor (PAI)-1, urokinase plasminogen activator (uPA), and its receptor (uPAR) in gastric epithelial cells and the consequences for epithelial cell proliferation. Real-time PCR of biopsies from gastric corpus, but not antrum, showed significantly increased PAI-1, uPA, and uPAR in H. pylori-positive patients. Transfection of primary human gastric epithelial cells with uPA, PAI-1, or uPAR promoters in luciferase reporter constructs revealed expression of all three in H+/K+ATPase- and vesicular monoamine transporter 2-expressing cells; uPA was also expressed in pepsinogen- and uPAR-containing trefoil peptide-1-expressing cells. In each case expression was increased in response to H. pylori and for uPA, but not PAI-1 or uPAR, required the virulence factor CagE. H. pylori also stimulated soluble and cell surface-bound uPA activity, and both were further increased by PAI-1 knockdown, consistent with PAI-1 inhibition of endogenous uPA. H. pylori stimulated epithelial cell proliferation, which was inhibited by uPA immunoneutralization and uPAR knockdown; exogenous uPA also stimulated proliferation that was further increased after PAI-1 knockdown. The proliferative effects of uPA were inhibited by immunoneutralization of the EGF receptor and of heparin-binding EGF (HB-EGF) by the mutant diphtheria toxin CRM197 and an EGF receptor tyrosine kinase inhibitor. H. pylori induction of uPA therefore leads to epithelial proliferation through activation of HB-EGF and is normally inhibited by concomitant induction of PAI-1; treatments directed at inhibition of uPA may slow the progression to gastric cancer.

Kenny, Susan; Duval, Cedric; Sammut, Stephen J.; Steele, Islay; Pritchard, D. Mark; Atherton, John C.; Argent, Richard H.; Dimaline, Rod; Dockray, Graham J.; Varro, Andrea

2008-01-01

217

Plasminogen activator inhibitor-1 suppresses endogenous fibrinolysis in a canine model of pulmonary embolism  

International Nuclear Information System (INIS)

Plasminogen activator inhibitor-1 (PAI-1), the specific, fast-acting inhibitor of tissue-type plasminogen activator (t-PA), binds to fibrin and has been found in high concentrations within arterial thrombi. These findings suggest that the localization of PAI-1 to a thrombus protects that same thrombus from fibrinolysis. In this study, clot-bound PAI-1 was assessed for its ability to suppress clot lysis in vivo. Autologous, canine whole blood clots were formed in the presence of increasing amounts of activated PAI-1 (0-30 micrograms/ml). Approximately 6-8% of the PAI-1 bound to the clots under the experimental conditions. Control and PAI-1-enriched clots containing iodine-125-labeled fibrin (ogen) were homogenized, washed to remove nonbound elements, and delivered to the lungs of anesthetized dogs where the homogenates subsequently underwent lysis by the endogeneous fibrinolytic system. 125I-labeled fibrin degradation products appeared in the blood of control animals within 10 minutes and were maximal by 90 minutes. PAI-1 reduced fibrin degradation product release in a dose-responsive manner at all times between 30 minutes and 5 hours (greater than or equal to 76% inhibition at 30 minutes, PAI-1 greater than or equal to 6 micrograms/ml). PAI-1 also suppressed D-dimer release from clots containing small amounts of human fibrin (ogen). t-PA administration attenuated the effects of PAI-1, whereas latent PAI-1 (20 micrograms/ml) had no effect on clot lysis. Blood levels of PA and PAI activity remained unaltered during these experiments. The results indicate that PAI-1 markedly inhibits endogenous fibrinolysis in vivo and, moreover, suggest that the localization of PAI-1 to a forming thrombus is an important physiological mechanism for subsequent thrombus stabilization.

1991-01-01

218

Plasminogen activator inhibitor-1 suppresses endogenous fibrinolysis in a canine model of pulmonary embolism  

Energy Technology Data Exchange (ETDEWEB)

Plasminogen activator inhibitor-1 (PAI-1), the specific, fast-acting inhibitor of tissue-type plasminogen activator (t-PA), binds to fibrin and has been found in high concentrations within arterial thrombi. These findings suggest that the localization of PAI-1 to a thrombus protects that same thrombus from fibrinolysis. In this study, clot-bound PAI-1 was assessed for its ability to suppress clot lysis in vivo. Autologous, canine whole blood clots were formed in the presence of increasing amounts of activated PAI-1 (0-30 micrograms/ml). Approximately 6-8% of the PAI-1 bound to the clots under the experimental conditions. Control and PAI-1-enriched clots containing iodine-125-labeled fibrin (ogen) were homogenized, washed to remove nonbound elements, and delivered to the lungs of anesthetized dogs where the homogenates subsequently underwent lysis by the endogeneous fibrinolytic system. 125I-labeled fibrin degradation products appeared in the blood of control animals within 10 minutes and were maximal by 90 minutes. PAI-1 reduced fibrin degradation product release in a dose-responsive manner at all times between 30 minutes and 5 hours (greater than or equal to 76% inhibition at 30 minutes, PAI-1 greater than or equal to 6 micrograms/ml). PAI-1 also suppressed D-dimer release from clots containing small amounts of human fibrin (ogen). t-PA administration attenuated the effects of PAI-1, whereas latent PAI-1 (20 micrograms/ml) had no effect on clot lysis. Blood levels of PA and PAI activity remained unaltered during these experiments. The results indicate that PAI-1 markedly inhibits endogenous fibrinolysis in vivo and, moreover, suggest that the localization of PAI-1 to a forming thrombus is an important physiological mechanism for subsequent thrombus stabilization.

Reilly, C.F.; Fujita, T.; Hutzelmann, J.E.; Mayer, E.J.; Shebuski, R.J. (Department of Pharmacology, Merck Sharp Dohme Research Laboratories, West Point, PA (USA))

1991-07-01

219

Hyperoxia enhanced the production of plasminogen activator by cultured pulmonary artery endothelial cells  

Energy Technology Data Exchange (ETDEWEB)

Pulmonary artery endothelial cell (EC) monolayers exposed to hyperoxia show increased permeability to albumin and marked alterations in actin filament distribution. The mechanism for these cytoskeletal changes is unknown. The authors now report that cells exposed to hyperoxia (95% O{sub 2}) produce significant quantities of urokinase-type plasminogen activators (u-PA). Zymographic analysis revealed that plasminogen-dependent caseinolytic activity in conditioned media from O{sub 2}-exposed cells was several fold higher than controls, especially at 48 hr. Cell-associated lytic activity was markedly increased at 48 and 72 hr when oxidative effects on the cytoskeleton were most apparent. Amidolytic assays confirmed these findings. (1) Conditioned media, CTA U/ml (mean {+-} SEM): Control 0.73{+-}0.05 vs 48 hr O{sub 2} 2.09{+-}0.50, (2) Cell-associated activity (preparations enriched for adhesion plaques), CTA mU/10{sup 6} cells: Control 0.17{+-}0.06; O{sub 2}: 24 hr 0.18{+-}0.07; 48 hr 0.46{+-}0.08; 72 hr 0.48{+-}0.08; O{sub 2} 48 hr or 72 hr vs Control. Immunocytochemical analysis demonstrated breakdown and restructuring of fibronectin and collagen components of the extracellular matrix at 48 and 72 hours. They conclude that hyperoxia enhanced both PA production and dismantling of matrix by EC. These changes may in part be responsible for some of the actin filament alterations which occur in conjunction with O{sub 2}-induced permeability increases.

Phillips, P.G.; Ryan, T.J.; Birnby, L.; Tsan, M.F. (Albany Medical College, NY (United States) New York State Health Lab., Albany (United States))

1990-02-26

220

Effects of Qinggan Huoxue Recipe and its separated recipes on urokinase-type plasminogen activator and plasminogen activator inhibitor-1 fibrinolytic system in rats with alcoholic liver fibrosis  

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Full Text Available Objective: To study the action mechanisms of Qinggan Huoxue Recipe (QGHXR), a compound traditional Chinese herbal medicine, and its separated recipes by observing their effects on expressions of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in rats with alcoholic liver fibrosis (ALF).Methods: A total of 150 SD rats were divided into three groups: blank group, carbon tetrachloride (CCl4) group and ALF-inducing group. Rats in the ALF-inducing group were administered with a mixture diet (56% alcohol 10 mL/kg, corn oil 2 mL/kg, pyrazole 25 mg/kg) once daily and intraperitoneally injected with 0.3 mL/kg 25% solution of CCl4 in olive oil twice weekly. The CCl4 group was intraperitoneally injected with equal volume of CCl4 and olive oil as the ALF-inducing group and ingested normal saline (12 mL/kg per day). The blank group was intraperitoneally injected with and ingested saline in equal volumes of the above. At the end of the eighth week, the survived rats in the ALF-inducing group were divided into four subgroups: untreated group, QGHXR group, Qinggan Recipe (QGR) group and Huoxue Recipe (HXR) group. The three treated groups were given corresponding drugs respectively (4.75, 1.5, 3.25 g/kg). The blank group, CCl4 group and untreated group were given normal saline in equal volume (5 mL/kg per day). All rats were anaesthetized and killed at the end of the twelfth week. The activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum were analyzed. Pathological changes in liver tissues were observed by hematoxylin and eosin staining and Masson staining. The expressions of uPA and PAI-1 were evaluated with Western blotting, immunofluorescence, and real-time polymerase chain reaction.Results: There existed obvious liver fibrosis in liver tissues in the untreated group as compared with the blank group (P<0.01), and the activities of ALT and AST and the expressions of uPA and PAI-1 also increased in the untreated group. QGHXR and its separated recipes could improve the degree of liver fibrosis (P<0.01). QGHXR and its separated recipes could degrade the activity of ALT as compared with the untreated group; QGHXR and its separated recipes advanced the expression of uPA, and decreased the expression of PAI-1 significantly as compared with the untreated group. The effect of QGHXR was the best among the three recipes.Conclusion: QGHXR and its separated recipes may improve ALF in rats by decreasing the expression of PAI-1 and advance the expression of uPA. The effect of QGHXR is the best among them.

Jun-ming CHEN; Guang JI

2009-01-01

 
 
 
 
221

Urokinase-type Plasminogen Activator-like Proteases in Teleosts Lack Genuine Receptor-binding Epidermal Growth Factor-like Domains  

DEFF Research Database (Denmark)

Plasminogen activation catalyzed by urokinase-type plasminogen activator (uPA) plays an important role in normal and pathological tissue remodeling processes. Since its discovery in the mid-1980s, the cell membrane-anchored urokinase-type plasminogen activator receptor (uPAR) has been believed to be central to the functions of uPA, as uPA-catalyzed plasminogen activation activity appeared to be confined to cell surfaces through the binding of uPA to uPAR. However, a functional uPAR has so far only been identified in mammals. We have now cloned, recombinantly produced, and characterized two zebrafish proteases, zfuPA-a and zfuPA-b, which by several criteria are the fish orthologs of mammalian uPA. Thus, both proteases catalyze the activation of fish plasminogen efficiently and both proteases are inhibited rapidly by plasminogen activator inhibitor-1 (PAI-1). But zfuPA-a differs from mammalian uPA by lacking the exon encoding the uPAR-binding epidermal growth factor-like domain; zfuPA-b differs from mammalian uPA by lacking two cysteines of the epidermal growth factor-like domain and a uPAR-binding sequence comparable with that found in mammalian uPA. Accordingly, no zfuPA-b binding activity could be found in fish white blood cells or fish cell lines. We therefore propose that the current consensus of uPA-catalyzed plasminogen activation taking place on cell surfaces, derived from observations with mammals, is too narrow. Fish uPAs appear incapable of receptor binding in the manner known from mammals and uPA-catalyzed plasminogen activation in fish may occur mainly in solution. Studies with nonmammalian vertebrate species are needed to obtain a comprehensive understanding of the mechanism of plasminogen activation.

Bager, René; Kristensen, Thomas Kielsgaard

2012-01-01

222

Calcium spirulan as an inducer of tissue-type plasminogen activator in human fetal lung fibroblasts.  

Science.gov (United States)

Calcium spirulan (Ca-SP), a novel sulfated polysaccharide isolated from the blue-green alga Spirulina platensis, has been found to have antiviral and heparin cofactor II-dependent antithrombin activities. We have obtained evidence that Ca-SP is a potent inducer of tissue-type plasminogen activator (t-PA) production. The addition of Ca-SP to a culture of IMR-90 human fetal lung fibroblasts increased t-PA concentrations in the conditioned medium, in a dose- and time-dependent manner, but in the cell lysate, t-PA concentrations were unchanged, suggesting that t-PA induced by Ca-SP is easily secreted into the conditioned medium. The amount of newly synthesized t-PA in IMR-90 cells, as measured by labeling with [35S]methionine and subsequent immunoprecipitation of t-PA from conditioned medium, was significantly increased by Ca-SP-stimulation. However, Ca-SP did not increase the t-PA mRNA levels. As previously reported, thrombin stimulated t-PA gene transcription in IMR-90 cells, and the simultaneous treatment with Ca-SP and thrombin caused further enhancement of t-PA production, in a synergistic manner. It would thus appear that Ca-SP increases t-PA production through post-transcriptional processes. IMR-90 cells also produce plasminogen activator inhibitor type-1 (PAI-1), but Ca-SP showed little effect on the PAI-1 production. H-SP, which was obtained by removing the calcium from Ca-SP, had no effect on the t-PA production. Na-SP, which was prepared by replacement of the calcium with sodium, stimulated the t-PA production similarly to Ca-SP. Thus, Ca-SP specifically induces t-PA production, and the molecular conformation of Ca-SP maintained by Ca or Na may be essential for the stimulation of t-PA synthesis. PMID:9060995

Hayakawa, Y; Hayashi, T; Hayashi, K; Ozawa, T; Niiya, K; Sakuragawa, N

1997-03-01

223

Calcium spirulan as an inducer of tissue-type plasminogen activator in human fetal lung fibroblasts.  

UK PubMed Central (United Kingdom)

Calcium spirulan (Ca-SP), a novel sulfated polysaccharide isolated from the blue-green alga Spirulina platensis, has been found to have antiviral and heparin cofactor II-dependent antithrombin activities. We have obtained evidence that Ca-SP is a potent inducer of tissue-type plasminogen activator (t-PA) production. The addition of Ca-SP to a culture of IMR-90 human fetal lung fibroblasts increased t-PA concentrations in the conditioned medium, in a dose- and time-dependent manner, but in the cell lysate, t-PA concentrations were unchanged, suggesting that t-PA induced by Ca-SP is easily secreted into the conditioned medium. The amount of newly synthesized t-PA in IMR-90 cells, as measured by labeling with [35S]methionine and subsequent immunoprecipitation of t-PA from conditioned medium, was significantly increased by Ca-SP-stimulation. However, Ca-SP did not increase the t-PA mRNA levels. As previously reported, thrombin stimulated t-PA gene transcription in IMR-90 cells, and the simultaneous treatment with Ca-SP and thrombin caused further enhancement of t-PA production, in a synergistic manner. It would thus appear that Ca-SP increases t-PA production through post-transcriptional processes. IMR-90 cells also produce plasminogen activator inhibitor type-1 (PAI-1), but Ca-SP showed little effect on the PAI-1 production. H-SP, which was obtained by removing the calcium from Ca-SP, had no effect on the t-PA production. Na-SP, which was prepared by replacement of the calcium with sodium, stimulated the t-PA production similarly to Ca-SP. Thus, Ca-SP specifically induces t-PA production, and the molecular conformation of Ca-SP maintained by Ca or Na may be essential for the stimulation of t-PA synthesis.

Hayakawa Y; Hayashi T; Hayashi K; Ozawa T; Niiya K; Sakuragawa N

1997-03-01

224

Thrombolysis with intravenous tissue plasminogen activator predicts a favorable discharge disposition in patients with acute ischemic stroke.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: Acute ischemic stroke patients who receive recombinant tissue plasminogen activator (rt-PA) within 3 hours of symptom onset are 30% more likely to have minimal to no disability at 3 months. During hospitalization, short-term disability is subjectively measured by discharge disposition, whether to home, inpatient rehabilitation, a skilled nursing facility, or subacute care. There are no studies assessing the role of recombinant tissue plasminogen activator use as a predictor of poststroke discharge disposition. METHODS: We conducted a retrospective analysis of all patients with ischemic stroke who presented within the original three hour window for intravenous thrombolysis, and who were admitted to the University of Texas Houston Medical School Stroke Service at Memorial Hermann Hospital - Texas Medical Center between January 2004 and October 2009. Baseline demographics and National Institute of Health Stroke Scale score were collected. Cerebrovascular disease risk factors were used for risk stratification in the multivariate regression. RESULTS: Out of 2225 patients with acute ischemic stroke, 1019 were discharged to home, 719 to inpatient rehabilitation, 371 to a skilled nursing facility and 116 to subacute care. Patients who received recombinant tissue plasminogen activator therapy were more likely to be discharged home compared to the other levels of care (P<0.0001; OR, 1.945; 95% CI, 1.538 to 2.459). Considering post-acute inpatient rehabilitation versus skilled nursing facility/subacute care and disposition at a skilled nursing facility versus subacute care, there were no differences in disposition between patients who received recombinant tissue plasminogen activator therapy. Inpatient Rehabilitation versus Skilled Nursing Facility or Subacute Care (P = 0.123); Skilled Nursing Facility versus Subacute Care (P = 0.605). CONCLUSIONS: Patients who receive intravenous recombinant tissue plasminogen activator as treatment for acute ischemic stroke are more likely to be discharged directly home after hospitalization. This study is limited by its retrospective nature and the undetermined role of psychosocial factors related to discharge.

Ifejika-Jones NL; Harun N; Mohammed-Rajput NA; Noser EA; Grotta JC

2011-03-01

225

Ovine contagious epididymitis: a review.  

UK PubMed Central (United Kingdom)

Ovine contagious epididymitis is predominantly associated with Brucella ovis, Actinobacillus seminis and a variety of organisms including Histophilus ovis. Transmission occurs venereally or by homosexual activity and, in the case of Actinobacillus seminis, ewe to lamb transmission is probably important. A chronic infection, mainly in the cauda epididymis may result in formation of spermatic granulomata and a reduction in ram fertility. Eradication of ovine brucellosis can be achieved by serological testing using a complement-fixation test in conjunction with palpation of lesions and removal of reactors. Vaccination to control ovine brucellosis is advocated in some countries. The nomenclature of the group of Gram-negative pleomorphic organisms to which Actinobacillus seminis and Histophilus ovis belong is urgently in need of review. This paper reviews the organisms capable of producing ovine contagious epididymitis, the pathogenesis of the condition as well as methods of diagnosis and control.

Burgess GW

1982-12-01

226

Concentrations of plasminogen activator inhibitor-1 (PAI-1) and urokinase plasminogen activator (uPA) in induced sputum of asthma patients after allergen challenge  

Directory of Open Access Journals (Sweden)

Full Text Available Urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) are involved in tiisue remodeling and repairprocesses associated with acute and chronic inflammation. The aim of the study was to evaluate the effect of allergen challengeon concentration of uPA and PAI-1 in induced sputum of house dust mite allergic asthmatics (HDM-AAs). ThirtyHDM-AAs and ten healthy persons (HCs)were recruited for the study. In 24 HDM-AAs bronchial challenge with Dermatophagoidespteronyssinus (Dp) and in 6 HDM-AAs sham challenege with saline were performed. In HDM-AAs sputumwas induced 24 hours before (T0) and 24 hours (T24) after the challenge. Concentration of uPA and PAI-1 in induced sputumwere determined using immunoenzymatic assays. At T0 in HDM-AAs mean sputum uPA (151±96 pg/ml) and PAI-1(4341±1262 pg/ml) concentrations were higher than in HC (18.8±6.7 pg/ml; p=0.0002 and 596±180 pg/ml; p<0.0001; foruPA and PAI-1 respectively). After allergen challenge further increase in sputum uPA (187±144 pg/ml; p=0.03) and PAI-1(6252±2323 pg/ml; p<0.0001) concentrations were observed. Moreover, in Dp challenged, but not in saline challengedHDM-AAs the mean uPA/PAI-1 ratio decreased significantly at T24. No significant increase in the studied parameters werefound in sham challenged patients. In HDM-AAs allergen exposure leads to activation of the plasmin system in the airways.Greater increase of the PAI-1 concentration than uPA concentration after allergen challenge may promote airway remodelingand play an important role in the development of bronchial hyperreactivity.

Krzysztof Kowal,; Marcin Moniuszko; Sebastian Zukowski; Anna Bodzenta-Lukaszyk

2010-01-01

227

Concentrations of plasminogen activator inhibitor-1 (PAI-1) and urokinase plasminogen activator (uPA) in induced sputum of asthma patients after allergen challenge.  

Directory of Open Access Journals (Sweden)

Full Text Available Urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) are involved in tiisue remodeling and repair processes associated with acute and chronic inflammation. The aim of the study was to evaluate the effect of allergen challenge on concentration of uPA and PAI-1 in induced sputum of house dust mite allergic asthmatics (HDM-AAs). Thirty HDM-AAs and ten healthy persons (HCs)were recruited for the study. In 24 HDM-AAs bronchial challenge with Dermatophagoides pteronyssinus (Dp) and in 6 HDM-AAs sham challenege with saline were performed. In HDM-AAs sputum was induced 24 hours before (T0) and 24 hours (T24) after the challenge. Concentration of uPA and PAI-1 in induced sputum were determined using immunoenzymatic assays. At T0 in HDM-AAs mean sputum uPA (151 Â? 96 pg/ml) and PAI-1 (4341 Â? 1262 pg/ml) concentrations were higher than in HC (18.8 Â? 6.7 pg/ml; p=0.0002 and 596 Â? 180 pg/ml; p<0.0001; for uPA and PAI-1 respectively). After allergen challenge further increase in sputum uPA (187 Â? 144 pg/ml; p=0.03) and PAI-1 (6252 Â? 2323 pg/ml; p<0.0001) concentrations were observed. Moreover, in Dp challenged, but not in saline challenged HDM-AAs the mean uPA/PAI-1 ratio decreased significantly at T24. No significant increase in the studied parameters were found in sham challenged patients. In HDM-AAs allergen exposure leads to activation of the plasmin system in the airways. Greater increase of the PAI-1 concentration than uPA concentration after allergen challenge may promote airway remodeling and play an important role in the development of bronchial hyperreactivity.

Krzysztof Kowal; Marcin Moniuszko; Sebastian Zukowski; Anna Bodzenta-Lukaszyk

2011-01-01

228

Tissue plasminogen activator for acute ischemic stroke: a New York city emergency medicine perspective.  

Science.gov (United States)

Nationally, only 2-3% of patients with acute ischemic stroke (AIS) currently receive tissue plasminogen activator (TPA). To better understand the reasons, we investigated the practice patterns, level of familiarity and acceptance of TPA for AIS among emergency physicians in New York City (NYC). Fifty-seven 911-receiving hospital emergency department directors were surveyed regarding TPA use. Of those responding, 37% had never used TPA to treat AIS. Lack of neurological support was reported by 33%. Departments with formal protocols were more likely to use TPA for AIS. In conclusion, there is considerable variation in the practice, knowledge, and attitudes regarding the use of TPA for AIS in NYC emergency departments. Improved educational efforts and institutional support may be necessary to ensure the appropriate use of TPA by emergency physicians. PMID:16243196

Chan, Yu-Feng; Kwiatkowski, Thomas G; Rella, Joseph G; Rennie, William P; Kwon, Robert K; Silverman, Robert A

2005-11-01

229

Tissue plasminogen activator for acute ischemic stroke: a New York city emergency medicine perspective.  

UK PubMed Central (United Kingdom)

Nationally, only 2-3% of patients with acute ischemic stroke (AIS) currently receive tissue plasminogen activator (TPA). To better understand the reasons, we investigated the practice patterns, level of familiarity and acceptance of TPA for AIS among emergency physicians in New York City (NYC). Fifty-seven 911-receiving hospital emergency department directors were surveyed regarding TPA use. Of those responding, 37% had never used TPA to treat AIS. Lack of neurological support was reported by 33%. Departments with formal protocols were more likely to use TPA for AIS. In conclusion, there is considerable variation in the practice, knowledge, and attitudes regarding the use of TPA for AIS in NYC emergency departments. Improved educational efforts and institutional support may be necessary to ensure the appropriate use of TPA by emergency physicians.

Chan YF; Kwiatkowski TG; Rella JG; Rennie WP; Kwon RK; Silverman RA

2005-11-01

230

Expression of neuroserpin, a selective inhibitor of tissue-type plasminogen activator in the human skin.  

UK PubMed Central (United Kingdom)

Serine protease of the fibrinolytic system and their specific inhibitors, the serine protease inhibitors (SERPINs) are implicated in a number of physiological and pathological processes in skin. The main SERPIN is the plasminogen activator inhibitor-1 (or PAI-1), which is involved in wound healing and in pathogenesis of several diseases including skin fibrosis. Another member of SERPIN superfamily, the neuroserpin (NSP), is widely expressed in the central nervous system. It has been recently detected in different organs such as pancreas, heart, kidney and testis. In this study, we provided evidences for the presence of NSP in the skin, in 10 human skin samples (HSS) at mRNA level (RT-PCR) and protein level (Western blot and immunohistochemistry). The immunohistochemistry analysis showed that this expression was located in dermis around blood vessels.

Chéret J; Lebonvallet N; Misery L; Le Gall-Ianotto C

2012-09-01

231

Intra-arterial tissue plasminogen activator and abciximab in patients with acute basilar artery occlusion.  

UK PubMed Central (United Kingdom)

Acute basilar artery occlusion has a poor prognosis and best treatment has not been assessed yet; as for intra-arterial treatment, no "gold standard" exists. We evaluated a series of ten patients treated with intra-arterial combination of recombinant tissue plasminogen activator (rtPA) and abciximab. Partial/complete recanalisation was achieved in all patients and good outcome (1 month Modified Rankin Scale 0-2) in eight cases, while one patient had symptomatic intracranial haemorrhage and died. Such outcome appears significantly better if compared with the results of Basilar Artery International Cooperation Study, suggesting that intra-arterial administration of rtPA and abciximab may be a promising option in patients with acute basilar artery occlusion undergoing endovascular treatment.

Chiti A; Gialdini G; Terni E; Giannini N; Gennaro M; Lazzarotti GA; Puglioli M; Orlandi G; Bonuccelli U

2013-05-01

232

Determinants of plasminogen activator inhibitor-1 in South Asians with ischaemic stroke.  

UK PubMed Central (United Kingdom)

To investigate the relationship of circulating plasminogen activator inhibitor-1 (PAI-1) levels with features of insulin resistance and genotype at a single nucleotide insertion/deletion (4G/5G) polymorphism in the promoter region of the PAI-1 gene in 101 South Asian ischaemic stroke patients and 102 symptom-free reference subjects. The allele frequencies were 4G-0.51, 5G-0.49 and 4G-0.61, 5G-0.39 in patients and reference subjects, respectively. There was a significant association between PAI-1 promoter genotype and PAI-1 antigen levels in patients. Regression analysis with significant correlates in the model demonstrated age, gender and triglycerides in patients and fasting insulin and HDL cholesterol in reference subjects as independent predictors of PAI-1 antigen.

Kain K; Young J; Bamford J; Bavington J; Grant PJ; Catto AJ

2002-01-01

233

[Right atrial thrombus: a rare presentation of plasminogen activator inhibitor deficiency].  

UK PubMed Central (United Kingdom)

Free-floating right atrial thrombi are rare but associated with high mortality. Although advances in echocardiography have improved diagnosis, their management is still the subject of debate. A 24-year-old woman with a history of smoking, obesity and oral contraceptive use presented to the emergency department with dyspnea, cough and hemoptysis. Transthoracic echocardiography revealed a large free-floating cardiac mass occupying the right atrial chamber and restricting tricuspid valve opening. In view of recurrent pulmonary embolism, she was referred for cardiac surgery and the cardiac mass was excised. Anatomopathological analysis revealed an organized and calcified thrombus. Genetic study showed her to be homozygous for the 4G/4G allelic variant of plasminogen activator inhibitor-1 and heterozygous for the allelic variant A1298C of 5,10-methylenetetrahydrofolate reductase.

Cordeiro Piçarra B; Santos AR; Dionísio P; Vasconcelos J; Banazol N; Lourenço S; Caetano F; Jara A

2012-02-01

234

[Characterization of the primary structure of TNK-tissue plasminogen activator using LC-MS].  

UK PubMed Central (United Kingdom)

The primary structure of TNK-tissue plasminogen activator (TNK-tPA) was characterized using liquid chromatography-mass spectrometry (LC-MS). Firstly, the molecular mass of deglycosylated protein was measured. Then peptide mass mapping and MS/MS of the reduced, alkylated and trypsin-digested sample were tested and analyzed so as to verify its amino acid sequence and identify post-translational modifications. Results show that the amino acid sequence was consistent with designed structure; about 5% of M207 was oxidized; T61 was fucosylated with -80% occupancy; N103, N448 and N184 (-15% occupancy) were glycosylated with complex-type oligosaccharides. LC-MS coupled with proper sample pretreatment is approved to be a rapid and powerful approach to characterize the primary structure of TNK-tPA.

Tao L; Ding YX; Guo Y; Rao CM; Wang JZ

2013-06-01

235

Tissue-type plasminogen activator binds to A? and AIAPP amyloid fibrils with multiple domains.  

UK PubMed Central (United Kingdom)

Binding of tissue-type plasminogen activator (tPA) to amyloid and denatured proteins is reported in a number of studies. The binding site has been mapped previously to the finger domain of tPA. In this study, tPA and truncated tPA constructs, lacking the finger domain, were tested for their ability to bind to A? and AIAPP amyloid-like fibrils. Surface plasmon resonance experiments and pull-down assays clearly show that indeed tPA binds, but that the finger domain is not essential. Another possible binding mechanism via the lysine binding site on the kringle 2 domain was also not crucial for the binding. Immuno-electron microscopy studies show that tPA binds to fibril sides. This study shows that, besides the finger domain, other domains in tPA are involved in amyloid binding.

Beringer DX; Fischer MJ; Meeldijk JD; van Donselaar EG; de Mol NJ; Kroon-Batenburg LM

2013-06-01

236

IV tissue plasminogen activator use in acute stroke: What are neurologists thinking?  

UK PubMed Central (United Kingdom)

Stroke remains among the top 4 causes of death in the United States and, despite advances in inpatient care and rehabilitation, the leading cause of severe disability. Furthermore, despite being a proven effective therapy, tissue plasminogen activator (tPA) use remains dramatically low, in ?2% of all stroke patients in a community setting.(1) In this issue of Neurology(®), Shamy(2) addresses the use of tPA in appropriate clinical settings and neurologists' rationale for their decisions. Given the mortality and morbidity associated with stroke, the data for substantial benefit with tPA use, and Food and Drug Administration approval, the limited use of tPA raises ethical and legal concerns.

Boissy AR

2013-08-01

237

Ischaemia-reperfusion injury impairs tissue plasminogen activator release in man  

DEFF Research Database (Denmark)

AimsIschaemia-reperfusion (IR) injury causes endothelium-dependent vasomotor dysfunction that can be prevented by ischaemic preconditioning. The effects of IR injury and preconditioning on endothelium-dependent tissue plasminogen activator (t-PA) release, an important mediator of endogenous fibrinolysis, remain unknown.Methods and resultsIschaemia-reperfusion injury (limb occlusion at 200 mmHg for 20 min) was induced in 22 healthy subjects. In 12 subjects, IR injury was preceded by local or remote ischaemic preconditioning (three 5 min episodes of ipsilateral or contralateral limb occlusion, respectively) or sham in a randomized, cross-over trial. Forearm blood flow (FBF) and endothelial t-PA release were assessed using venous occlusion plethysmography and venous blood sampling during intra-arterial infusion of acetylcholine (5-20 µg/min) or substance P (2-8 pmol/min). Acetylcholine and substance P caused dose-dependent increases in FBF (P

Pedersen, Christian MØller; Barnes, Gareth

2011-01-01

238

Intravitreal recombinant tissue plasminogen activator in the treatment of experimentally induced bacterial endophthalmitis.  

UK PubMed Central (United Kingdom)

Intravitreal injection of antibiotics has been shown to be effective in the treatment of bacterial endophthalmitis, but does not prevent the formation of fibrin. Recombinant tissue plasminogen activator (rTPA), a fibrinolytic agent, was evaluated in experimentally induced Staphylococcus aureus endophthalmitis in an animal model. Significant fibrinous reaction in the vitreous was present in three of six eyes treated with intravitreal injection of clindamycin and rTPA (50%) and in one of five eyes treated with clindamycin only (20%). Fibrin clot formation in the anterior chamber was present in two of six eyes treated with clindamycin and rTPA (33%) and not observed in the clindamycin treated eyes (0%). These findings suggest that rTPA does not play a beneficial role in the treatment of bacterial endophthalmitis in the presence of the vitreous.

Baziuk N; Fang T; Peyman GA; Gremillion CM Jr

1991-03-01

239

Intravitreal recombinant tissue plasminogen activator in the treatment of experimentally induced bacterial endophthalmitis.  

Science.gov (United States)

Intravitreal injection of antibiotics has been shown to be effective in the treatment of bacterial endophthalmitis, but does not prevent the formation of fibrin. Recombinant tissue plasminogen activator (rTPA), a fibrinolytic agent, was evaluated in experimentally induced Staphylococcus aureus endophthalmitis in an animal model. Significant fibrinous reaction in the vitreous was present in three of six eyes treated with intravitreal injection of clindamycin and rTPA (50%) and in one of five eyes treated with clindamycin only (20%). Fibrin clot formation in the anterior chamber was present in two of six eyes treated with clindamycin and rTPA (33%) and not observed in the clindamycin treated eyes (0%). These findings suggest that rTPA does not play a beneficial role in the treatment of bacterial endophthalmitis in the presence of the vitreous. PMID:1902438

Baziuk, N; Fang, T; Peyman, G A; Gremillion, C M

1991-03-01

240

Stereotactic fibrinolysis of spontaneous intracerebral hematoma using infusion of recombinant tissue plasminogen activator.  

UK PubMed Central (United Kingdom)

PURPOSE: The authors present a prospective study on 10 patients with stereotactic infusion of tissue plasminogen activator (rtPA) intraparenchimal hemorrhage. METHODS: Between 1999 and 2000, 10 patients with deep seated hematomas in the basal ganglia were selected for stereotactic infusion of rtPA and spontaneous clot drainage. RESULTS: All cases had about 80% reduction of the hematoma volume in the CT scan at the third day. The intracranial pressure was normalized by the third day too. There were no local or systemic complications with the use of this thrombolytic. The results were shown by the Glasgow Outcome Scale with six patients in V, three in IV and one in III after 3 months. CONCLUSION: Early treatment and drainage with minimally invasive neurosurgery, can make these patients with deep-seated hematomas recover the consciousness and they can be rehabilitated earlier avoiding secondary complications.

Nasser JA; Falavigna A; Bezerra M; Martinez V; Freitas G; Alaminos A; Bonatelli A; Ferraz F

2002-06-01

 
 
 
 
241

Gastrin stimulates expression of plasminogen activator inhibitor-1 in gastric epithelial cells.  

Science.gov (United States)

Plasminogen activator inhibitor (PAI)-1 is associated with cancer progression, fibrosis and thrombosis. It is expressed in the stomach but the mechanisms controlling its expression there, and its biological role, are uncertain. We sought to define the role of gastrin in regulating PAI-1 expression and to determine the relevance for gastrin-stimulated cell migration and invasion. In gastric biopsies from subjects with elevated plasma gastrin, the abundances of PAI-1, urokinase plasminogen activator (uPA), and uPA receptor (uPAR) mRNAs measured by quantitative PCR were increased compared with subjects with plasma concentrations in the reference range. In patients with hypergastrinemia due to autoimmune chronic atrophic gastritis, there was increased abundance of PAI-1, uPA, and uPAR mRNAs that was reduced by octreotide or antrectomy. Immunohistochemistry revealed localization of PAI-1 to parietal cells and enterochromaffin-like cells in micronodular neuroendocrine tumors in hypergastrinemic subjects. Transcriptional mechanisms were studied by using a PAI-1-luciferase promoter-reporter construct transfected into AGS-G(R) cells. There was time- and concentration-dependent increase of PAI-1-luciferase expression in response to gastrin that was reversed by inhibitors of the PKC and MAPK pathways. In Boyden chamber assays, recombinant PAI-1 inhibited gastrin-stimulated AGS-G(R) cell migration and invasion, and small interfering RNA treatment increased responses to gastrin. We conclude that elevated plasma gastrin concentrations are associated with increased expression of gastric PAI-1, which may act to restrain gastrin-stimulated cell migration and invasion. PMID:21193525

Nørsett, Kristin G; Steele, Islay; Duval, Cedric; Sammut, Stephen J; Murugesan, Senthil V M; Kenny, Susan; Rainbow, Lucille; Dimaline, Rod; Dockray, Graham J; Pritchard, D Mark; Varro, Andrea

2010-12-30

242

Gastric expression of plasminogen activator inhibitor (PAI)-1 is associated with hyperphagia and obesity in mice.  

Science.gov (United States)

The adipokine plasminogen activator inhibitor (PAI)-1 is increased in plasma of obese individuals and exhibits increased expression in the stomachs of individuals infected with Helicobacter. To investigate the relevance of gastric PAI-1, we used 1.1 kb of the H(+)/K(+)? subunit promoter to overexpress PAI-1 specifically in mouse gastric parietal cells (PAI-1-H/K? mice). We studied the physiological, biochemical, and behavioral characteristics of these and mice null for PAI-1 or a putative receptor, urokinase plasminogen activator receptor (uPAR). PAI-1-H/K? mice had increased plasma concentrations of PAI-1 and increased body mass, adiposity, and hyperphagia compared with wild-type mice. In the latter, food intake was inhibited by cholecystokinin (CCK)8s, but PAI-1-H/K? mice were insensitive to the satiating effects of CCK8s. PAI-1-H/K? mice also had significantly reduced expression of c-fos in the nucleus tractus solitarius in response to CCK8s and refeeding compared with wild-type mice. Exogenous PAI-1 reversed the effects of CCK8s on food intake and c-fos levels in the nucleus tractus solitarius of wild-type mice, but not uPAR-null mice. Infection of C57BL/6 mice with Helicobacter felis increased gastric abundance of PAI-1 and reduced the satiating effects of CCK8s, whereas the response to CCK8s was maintained in infected PAI-1-null mice. In cultured vagal afferent neurons, PAI-1 inhibited stimulation of neuropeptide Y type 2 receptor (Y2R) expression by CCK8s. Thus, gastric expression of PAI-1 is associated with hyperphagia, moderate obesity, and resistance to the satiating effects of CCK indicating a new role in suppressing signals from the upper gut that inhibit food intake. PMID:23254194

Kenny, Susan; Gamble, Joanne; Lyons, Suzanne; Vlatkovic, Nikolina; Dimaline, Rod; Varro, Andrea; Dockray, Graham J

2012-12-18

243

Stimulated in vivo synthesis of plasminogen activator inhibitor-1 in human adipose tissue.  

UK PubMed Central (United Kingdom)

Plasminogen activator inhibitor type-1 (PAI-1) is one of the most important inhibitors of endogenous fibrinolysis. Adipose tissue is a suggested source of the elevated plasma levels of PAI-1 in obesity. The relation between PAI-1 and inflammation is of particular interest, but current knowledge regarding regulation of PAI-1 in adipose tissue is mainly based on animal studies or ex vivo experiments on human cultured adipocytes. So far, no study has described stimulated gene expression and protein synthesis of PAI-1 in vivo in human adipose tissue. We used open heart surgery as a model of acute systemic inflammation. Twenty-two male patients underwent blood sampling and omental and subcutaneous adipose tissue biopsies for gene expression studies before and after surgery. Expression and localisation of PAI-1 antigen was evaluated by immunohistochemistry. After surgery gene expression of PAI-1 increased 27-fold in omental adipose tissue and three-fold in subcutaneous adipose tissue, but no differences were found in tissue-type plasminogen activator (t-PA) mRNA. PAI-1 antigen was localised within endothelial cells and in the adipose tissue interstitium close to vessels. The upregulated gene expression and protein synthesis in adipose tissue was followed by increased concentrations of PAI-1 antigen in plasma. In conclusion, we present for the first time that an acute systemic inflammation in humans increased gene expression and protein synthesis of PAI-1 in adipose tissue and that this increase was most prominent in omental adipose tissue. PAI-1 synthesis in adipose tissue due to acute systemic inflammation may be a link between inflammation and impaired endogenous fibrinolysis.

Ekström M; Liska J; Eriksson P; Sverremark-Ekström E; Tornvall P

2012-09-01

244

Stimulated in vivo synthesis of plasminogen activator inhibitor-1 in human adipose tissue.  

Science.gov (United States)

Plasminogen activator inhibitor type-1 (PAI-1) is one of the most important inhibitors of endogenous fibrinolysis. Adipose tissue is a suggested source of the elevated plasma levels of PAI-1 in obesity. The relation between PAI-1 and inflammation is of particular interest, but current knowledge regarding regulation of PAI-1 in adipose tissue is mainly based on animal studies or ex vivo experiments on human cultured adipocytes. So far, no study has described stimulated gene expression and protein synthesis of PAI-1 in vivo in human adipose tissue. We used open heart surgery as a model of acute systemic inflammation. Twenty-two male patients underwent blood sampling and omental and subcutaneous adipose tissue biopsies for gene expression studies before and after surgery. Expression and localisation of PAI-1 antigen was evaluated by immunohistochemistry. After surgery gene expression of PAI-1 increased 27-fold in omental adipose tissue and three-fold in subcutaneous adipose tissue, but no differences were found in tissue-type plasminogen activator (t-PA) mRNA. PAI-1 antigen was localised within endothelial cells and in the adipose tissue interstitium close to vessels. The upregulated gene expression and protein synthesis in adipose tissue was followed by increased concentrations of PAI-1 antigen in plasma. In conclusion, we present for the first time that an acute systemic inflammation in humans increased gene expression and protein synthesis of PAI-1 in adipose tissue and that this increase was most prominent in omental adipose tissue. PAI-1 synthesis in adipose tissue due to acute systemic inflammation may be a link between inflammation and impaired endogenous fibrinolysis. PMID:22740034

Ekström, Mattias; Liska, Jan; Eriksson, Per; Sverremark-Ekström, Eva; Tornvall, Per

2012-06-28

245

Correlation between plasminogen activator inhibitor-1 (PAI-1) and infarct size in acute myocardial infarction  

International Nuclear Information System (INIS)

The purpose of this study was to clarify the effects of fibrinolytic changes on infarct size in patients with acute myocardial infarction (AMI). Thirty-one patients with first AMI were divided into 2 groups: 15 patients (group C) underwent neither direct percutaneous transluminal coronary angioplasty (PTCA) nor thrombolytic therapy and 16 patients (group P) underwent successful direct PTCA. We measured serial changes in plasma level of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1). Furthermore, the relationship of these factors with the size of perfusion defects in Thallium-201 myocardial imaging (extent score) and peak creatine kinase (CK) were studied. Results obtained were as follows: In group C, plasma PAI-1 levels showed a tendency to increase within 24 hours after the onset of AMI compared with the control values and remained high on the 28th day. In group P, these levels increased within 24 hours and gradually decreased from the 7th day to the 28th day, but remained high on the 28th day compared with the control values. In group C, plasma t-PA levels increased within 24 hours, decreased on the 7th day, and increased again on the 28th day. In group P, these levels increased within 24 hours and gradually decreased from the 7th day to the 28th day. In both groups, PAI-1 levels within 24 hours correlated positively with the extent score. In group C, PAI-1 levels on the 1st day correlated positively with the levels of peak CK on the 1st day. On the other hand, this correlations was not shown in the group P. From these results, it is suggested that the plasma PAI-1 has the characteristics of an acute phase reactant and the PAI-1 level within 24 hours after the onset of AMI reflects the infarct size. (author)

1998-01-01

246

Correlation between plasminogen activator inhibitor-1 (PAI-1) and infarct size in acute myocardial infarction  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to clarify the effects of fibrinolytic changes on infarct size in patients with acute myocardial infarction (AMI). Thirty-one patients with first AMI were divided into 2 groups: 15 patients (group C) underwent neither direct percutaneous transluminal coronary angioplasty (PTCA) nor thrombolytic therapy and 16 patients (group P) underwent successful direct PTCA. We measured serial changes in plasma level of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1). Furthermore, the relationship of these factors with the size of perfusion defects in Thallium-201 myocardial imaging (extent score) and peak creatine kinase (CK) were studied. Results obtained were as follows: In group C, plasma PAI-1 levels showed a tendency to increase within 24 hours after the onset of AMI compared with the control values and remained high on the 28th day. In group P, these levels increased within 24 hours and gradually decreased from the 7th day to the 28th day, but remained high on the 28th day compared with the control values. In group C, plasma t-PA levels increased within 24 hours, decreased on the 7th day, and increased again on the 28th day. In group P, these levels increased within 24 hours and gradually decreased from the 7th day to the 28th day. In both groups, PAI-1 levels within 24 hours correlated positively with the extent score. In group C, PAI-1 levels on the 1st day correlated positively with the levels of peak CK on the 1st day. On the other hand, this correlations was not shown in the group P. From these results, it is suggested that the plasma PAI-1 has the characteristics of an acute phase reactant and the PAI-1 level within 24 hours after the onset of AMI reflects the infarct size. (author)

Soeki, Takeshi; Tamura, Yoshiyuki; Takeichi, Naoki; Shinohara, Hisanori; Yui, Yasuko; Fukuda, Nobuo; Sui, Osamu [Zentsuji National Hospital, Kagawa (Japan)

1998-05-01

247

Structure of the human plasminogen activator inhibitor 1 gene: nonrandom distribution of introns  

International Nuclear Information System (INIS)

Plasminogen activator inhibitor 1 (PAI-1) is the primary inhibitor of tissue-type plasminogen activator and thus performs an essential role in the regulation of the fibrinolytic process. It is a member of a large family of serine protease inhibitors (serpins). The authors determined the structure of the PAI-1 gene in order to more completely investigate the relationship of PAI-1 to other serpins and, at the same time, to begin to delineate structure-function relations in PAI-1 itself. A human genomic cosmid DNA library was screened and found to contain two independent clones, each harboring the entire PAI-1 gene. Restriction site mapping, electron microscopic inspection of heteroduplexes, and nucleotide sequence analysis all demonstrate that the PAI-1 gene is approximately 12.2 kilobase pairs in length and consists of nine exons and eight introns. All intron-exon boundaries are in accord with the GT-AG rule, including a cryptic acceptor splice site found in intron 7. The intron-exon pattern of the PAI-1 gene is distinct from that of most other serpins except that intron 3 of PAI-1 occupies an identical position as intron E of ovalbumin. Comparison of the authors data with the proposed subdomain structure of serpins suggests that seven of the eight introns may occupy a nonrandom position in the gene. These introns either delineate boundaries of individual structural subdomains or are located in random coil regions of the protein. Transcription of the PAI-1 gene in cultured vascular endothelial cells results in two distinct mRNA species. The data suggest that these two transcripts arise by alternative polyadenylation.

1987-01-01

248

RNA aptamers as conformational probes and regulatory agents for plasminogen activator inhibitor-1  

DEFF Research Database (Denmark)

The hallmark of serpins is the ability to undergo the so-called "stressed-to-relaxed" switch during which the surface-exposed reactive center loop (RCL) becomes incorporated as strand 4 in central beta-sheet A. RCL insertion drives not only the inhibitory reaction of serpins with their target serine proteases but also the conversion to the inactive latent state. RCL insertion is coupled to conformational changes in the flexible joint region flanking beta-sheet A. One interesting serpin is plasminogen activator inhibitor-1 (PAI-1), a fast and specific inhibitor of the serine proteases tissue-type and urokinase-type plasminogen activator. Via its flexible joints' region, native PAI-1 binds vitronectin and relaxed, protease-complexed PAI-1 certain endocytosis receptors. From a library of 35-nucleotides long 2'-fluoropyrimidine-containing RNA oligonucleotides, we have isolated two aptamers binding PAI-1 by the flexible joint region with low nanomolar K(D) values. One of the aptamers exhibited measurable binding to native PAI-1 only, while the other also bound relaxed PAI-1. While none of the aptamers inhibited the antiproteolytic effect of PAI-1, both aptamers inhibited vitronectin binding and the relaxed PAI-1-binding aptamer also endocytosis receptor binding. The aptamer binding exclusively to native PAI-1 increased the half-life for the latency transition to more than 6 h, manyfold more than vitronectin. Contact with Lys124 in the flexible joint region was critical for strong inhibition of the latency transition and the lack of binding to relaxed PAI-1. We conclude that aptamers yield important information about the serpin conformational switch and, because they can compete with high-affinity protein-protein interactions, may provide leads for pharmacological intervention.

Madsen, Jeppe B; Dupont, Daniel Miotto

2010-01-01

249

Solution structure of the kringle domain from urokinase-type plasminogen activator.  

UK PubMed Central (United Kingdom)

The solution structure of the kringle domain from urokinase-type plasminogen activator (u-PA) has been determined using 1H nuclear magnetic resonance spectroscopy and dynamical simulated annealing calculations. A total of 35 structures, 20 generated using a distance geometry method prior to simulated annealing and 15 generated using initial random phi, psi values, have been calculated based on 946 experimental nuclear Overhauser effect distance constraints and 48 dihedral angle constraints. Excluding the N- and C-terminal residues (-1 to 12, 77 to 82) and a number of surface residues (M18, G19, S42, D55 to R60, G67) that are disordered or flexible, the root mean square deviation values from the mean structure are 0.49(+/- 0.14) A and 0.65(+/- 0.16) A for the backbone atoms, and 1.03(+/- 0.21) A and 1.39(+/- 0.24) A for all heavy atoms, for the two sets of structures, respectively. An extended binding site for anionic polysaccharides such as heparin has been located on a relatively flat facet of the molecule, involving three consecutive arginines, R57, R58 and R60 (there is a deletion at site 59 of the consensus sequence), which form a cationic triad facing the solvent, and two histidines, H37 and H40, at the opposite end of the molecule. Comparison between the u-PA kringle structure and the crystal and NMR solution structures of tissue-type plasminogen activator kringle 2 has shown that the two proteins have similar global folds but demonstrate a number of local differences.

Li X; Bokman AM; Llinás M; Smith RA; Dobson CM

1994-02-01

250

Structure of the human plasminogen activator inhibitor 1 gene: nonrandom distribution of introns.  

UK PubMed Central (United Kingdom)

Plasminogen activator inhibitor 1 (PAI-1) is the primary inhibitor of tissue-type plasminogen activator and thus performs an essential role in the regulation of the fibrinolytic process. It is a member of a large family of serine protease inhibitors (serpins). We determined the structure of the PAI-1 gene in order to more completely investigate the relationship of PAI-1 to other serpins and, at the same time, to begin to delineate structure-function relations in PAI-1 itself. A human genomic cosmid DNA library was screened and found to contain two independent clones, each harboring the entire PAI-1 gene. Restriction site mapping, electron microscopic inspection of heteroduplexes, and nucleotide sequence analysis all demonstrate that the PAI-1 gene is approximately 12.2 kilobase pairs in length and consists of nine exons and eight introns. All intron-exon boundaries are in accord with the "GT-AG" rule, including a cryptic acceptor splice site found in intron 7. The intron-exon pattern of the PAI-1 gene is distinct from that of most other serpins except that intron 3 of PAI-1 occupies an identical position as intron E of ovalbumin. Comparison of our data with the proposed subdomain structure of serpins suggests that seven of the eight introns may occupy a nonrandom position in the gene. These introns either delineate boundaries of individual structural subdomains or are located in random coil regions of the protein. Transcription of the PAI-1 gene in cultured vascular endothelial cells results in two distinct mRNA species. Our data suggest that these two transcripts arise by alternative polyadenylation.

Loskutoff DJ; Linders M; Keijer J; Veerman H; van Heerikhuizen H; Pannekoek H

1987-06-01

251

Structure of the human plasminogen activator inhibitor 1 gene: nonrandom distribution of introns  

Energy Technology Data Exchange (ETDEWEB)

Plasminogen activator inhibitor 1 (PAI-1) is the primary inhibitor of tissue-type plasminogen activator and thus performs an essential role in the regulation of the fibrinolytic process. It is a member of a large family of serine protease inhibitors (serpins). The authors determined the structure of the PAI-1 gene in order to more completely investigate the relationship of PAI-1 to other serpins and, at the same time, to begin to delineate structure-function relations in PAI-1 itself. A human genomic cosmid DNA library was screened and found to contain two independent clones, each harboring the entire PAI-1 gene. Restriction site mapping, electron microscopic inspection of heteroduplexes, and nucleotide sequence analysis all demonstrate that the PAI-1 gene is approximately 12.2 kilobase pairs in length and consists of nine exons and eight introns. All intron-exon boundaries are in accord with the GT-AG rule, including a cryptic acceptor splice site found in intron 7. The intron-exon pattern of the PAI-1 gene is distinct from that of most other serpins except that intron 3 of PAI-1 occupies an identical position as intron E of ovalbumin. Comparison of the authors data with the proposed subdomain structure of serpins suggests that seven of the eight introns may occupy a nonrandom position in the gene. These introns either delineate boundaries of individual structural subdomains or are located in random coil regions of the protein. Transcription of the PAI-1 gene in cultured vascular endothelial cells results in two distinct mRNA species. The data suggest that these two transcripts arise by alternative polyadenylation.

Loskutoff, D.J.; Linders, M.; Keijer, J.; Veerman, H.; van Heerikhuizen, H.; Pannekoek, H.

1987-06-30

252

Structure of the human plasminogen activator inhibitor 1 gene: nonrandom distribution of introns.  

Science.gov (United States)

Plasminogen activator inhibitor 1 (PAI-1) is the primary inhibitor of tissue-type plasminogen activator and thus performs an essential role in the regulation of the fibrinolytic process. It is a member of a large family of serine protease inhibitors (serpins). We determined the structure of the PAI-1 gene in order to more completely investigate the relationship of PAI-1 to other serpins and, at the same time, to begin to delineate structure-function relations in PAI-1 itself. A human genomic cosmid DNA library was screened and found to contain two independent clones, each harboring the entire PAI-1 gene. Restriction site mapping, electron microscopic inspection of heteroduplexes, and nucleotide sequence analysis all demonstrate that the PAI-1 gene is approximately 12.2 kilobase pairs in length and consists of nine exons and eight introns. All intron-exon boundaries are in accord with the "GT-AG" rule, including a cryptic acceptor splice site found in intron 7. The intron-exon pattern of the PAI-1 gene is distinct from that of most other serpins except that intron 3 of PAI-1 occupies an identical position as intron E of ovalbumin. Comparison of our data with the proposed subdomain structure of serpins suggests that seven of the eight introns may occupy a nonrandom position in the gene. These introns either delineate boundaries of individual structural subdomains or are located in random coil regions of the protein. Transcription of the PAI-1 gene in cultured vascular endothelial cells results in two distinct mRNA species. Our data suggest that these two transcripts arise by alternative polyadenylation. PMID:2820474

Loskutoff, D J; Linders, M; Keijer, J; Veerman, H; van Heerikhuizen, H; Pannekoek, H

1987-06-30

253

Urokinase plasminogen activator induces pro-fibrotic/m2 phenotype in murine cardiac macrophages.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Inflammation and fibrosis are intertwined in multiple disease processes. We have previously found that over-expression of urokinase plasminogen activator in macrophages induces spontaneous macrophage accumulation and fibrosis specific to the heart in mice. Understanding the relationship between inflammation and fibrosis in the heart is critical to developing therapies for diverse myocardial diseases. Therefore, we sought to determine if uPA induces changes in macrophage function that promote cardiac collagen accumulation. METHODS AND RESULTS: We analyzed the effect of the uPA transgene on expression of pro-inflammatory (M1) and pro-fibrotic (M2) genes and proteins in hearts and isolated macrophages of uPA overexpressing mice. We found that although there was elevation of the pro-inflammatory cytokine IL-6 in hearts of transgenic mice, IL-6 is not a major effector of uPA induced cardiac fibrosis. However, uPA expressing bone marrow-derived macrophages are polarized to express M2 genes in response to IL-4 stimulation, and these M2 genes are upregulated in uPA expressing macrophages following migration to the heart. In addition, while uPA expressing macrophages express a transcriptional profile that is seen in tumor-associated macrophages, these macrophages promote collagen expression in cardiac but not embryonic fibroblasts. CONCLUSIONS: Urokinase plasminogen activator induces an M2/profibrotic phenotype in macrophages that is fully expressed after migration of macrophages into the heart. Understanding the mechanisms by which uPA modulates macrophage function may reveal insights into diverse pathologic processes.

Meznarich J; Malchodi L; Helterline D; Ramsey SA; Bertko K; Plummer T; Plawman A; Gold E; Stempien-Otero A

2013-01-01

254

Deleterious effects of plasminogen activators in neonatal cerebral hypoxia-ischemia.  

UK PubMed Central (United Kingdom)

The immature brains of newborns often respond differently from the brains of adults when exposed to similar insults. Previous studies have indicated that although hypoxia-ischemia (HI) induces persistent thrombosis in adult brains, it only modestly impairs blood perfusion in newborn brains. Here, we used the Vannucci model of HI encephalopathy to study age-related responses to cerebral HI in rat pups. We found that HI triggered fibrin deposition and impaired blood perfusion in both neonatal and adult brains. However, these effects were only transient in neonatal brains (<4 hours) and were accompanied by acute induction of both tissue-type and urinary-type plasminogen activators (tPA and uPA), which was not observed in adult brains subjected to the same insult. Interestingly, activation of the plasminogen system persisted up to 24 hours in neonatal brains, long after the clearance of fibrin-rich thrombi. Furthermore, astrocytes and macrophages outside blood vessels expressed tPA after HI, suggesting the possibility of tPA/plasmin-mediated cytotoxicity. Consistent with this hypothesis, injection of alpha2-antiplasmin into cerebral ventricles markedly ameliorated HI-induced damage to neurofilaments and white matter oligodendrocytes, providing a dose-response reduction of brain injury after 7 days of recovery. Conversely, ventricular injection of tPA increased HI-induced brain damage. Together, these results suggest that tPA/plasmin induction, which may contribute to acute fibrinolysis, is a critical component of extravascular proteolytic damage in immature brains, representing a new therapeutic target for the treatment of HI encephalopathy.

Adhami F; Yu D; Yin W; Schloemer A; Burns KA; Liao G; Degen JL; Chen J; Kuan CY

2008-06-01

255

Peroxisome proliferator-activated receptor-? activation inhibits hepatocellular carcinoma cell invasion by upregulating plasminogen activator inhibitor-1.  

UK PubMed Central (United Kingdom)

The peroxisome proliferator-activated receptor-? (PPAR?) is a ligand-activated transcription factor belonging to the nuclear receptor superfamily. Peroxisome proliferator-activated receptor-? ligands can inhibit cell growth and increase apoptosis of cancer cell lines, suggesting a potential role for PPAR? as a tumor suppressor. Whereas the related studies between PPAR? and cancer cell invasion are still poor. Our previous study indicates that ?-estradiol (E2) suppresses hepatocellular carcinoma (HCC) cell invasion. We report here that E2 can activate PPAR? of HCC cells, and activated PPAR? suppresses cell invasion by upregulating the expression level of plasminogen activator inhibitor-1 (PAI-1). We found that PPAR? plays an important role in the E2-induced HCC cell invasion process. Using PPAR? agonist GW1929, a reduced invasion effect was found in HCC cell lines, and this inhibition of cell invasion was dosage-dependent. However, cell invasion was restored by treatment with PPAR? antagonist GW9662. The activated PPAR? upregulated the expression of cell migration-related protein PAI-1. Furthermore, knockdown of PPAR? in HCC cells decreased the level of PAI-1 and advanced cell invasion in response to GW1929. On the contrary, overexpression of PPAR? in HCC cells elevated the level of PAI-1 and inhibited cell invasion. These findings suggest that PPAR? activation inhibits HCC cell invasion via the upregulation of PAI-1 and implicate that PPAR? is a target for the treatment and prevention of HCC cell invasion.

Pang X; Wei Y; Zhang Y; Zhang M; Lu Y; Shen P

2013-06-01

256

Biological activity of ovine IL-23 expressed using a foot-and-mouth disease virus 2A self-cleaving peptide.  

UK PubMed Central (United Kingdom)

Hetero-dimeric cytokines often require equi-molar expression of both subunits to achieve biological activity. Previously, we expressed ovine IL-12 p40 and p35 linked using a self-cleaving 2A peptide from foot-and-mouth disease virus (FMDV). We now generated a new improved vector for the expression of hetero-dimeric cytokines and demonstrate the more general applicability of this strategy by cloning and expressing ovine IL-23 using the 2A peptide to link IL-12/IL-23 p40 and p19. The resulting protein was shown to be biologically active when expressed in mammalian COS cells. IL-23 plays a significant role in the differentiation of Th17 cells as well as autoimmunity and the regulation of inflammatory processes. As such this reagents will be invaluable in the unravelling of regulation of the ovine immune system for both veterinary and human animal model applications.

Yen HH; Scheerlinck JP

2013-03-01

257

Intrapleural adenoviral delivery of human plasminogen activator inhibitor-1 exacerbates tetracycline-induced pleural injury in rabbits.  

UK PubMed Central (United Kingdom)

Elevated concentrations of plasminogen activator inhibitor-1 (PAI-1) are associated with pleural injury, but its effects on pleural organization remain unclear. A method of adenovirus-mediated delivery of genes of interest (expressed under a cytomegalovirus promoter) to rabbit pleura was developed and used with lacZ and human (h) PAI-1. Histology, ?-galactosidase staining, Western blotting, enzymatic and immunohistochemical analyses of pleural fluids (PFs), lavages, and pleural mesothelial cells were used to evaluate the efficiency and effects of transduction. Transduction was selective and limited to the pleural mesothelial monolayer. The intrapleural expression of both genes was transient, with their peak expression at 4 to 5 days. On Day 5, hPAI-1 (40-80 and 200-400 nM of active and total hPAI-1 in lavages, respectively) caused no overt pleural injury, effusions, or fibrosis. The adenovirus-mediated delivery of hPAI-1 with subsequent tetracycline-induced pleural injury resulted in a significant exacerbation of the pleural fibrosis observed on Day 5 (P = 0.029 and P = 0.021 versus vehicle and adenoviral control samples, respectively). Intrapleural fibrinolytic therapy (IPFT) with plasminogen activators was effective in both animals overexpressing hPAI-1 and control animals with tetracycline injury alone. An increase in intrapleural active PAI-1 (from 10-15 nM in control animals to 20-40 nM in hPAI-1-overexpressing animals) resulted in the increased formation of PAI-1/plasminogen activator complexes in vivo. The decrease in intrapleural plasminogen-activating activity observed at 10 to 40 minutes after IPFT correlates linearly with the initial concentration of active PAI-1. Therefore, active PAI-1 in PFs affects the outcome of IPFT, and may be both a biomarker of pleural injury and a molecular target for its treatment.

Karandashova S; Florova G; Azghani AO; Komissarov AA; Koenig K; Tucker TA; Allen TC; Stewart K; Tvinnereim A; Idell S

2013-01-01

258

A novel plasminogen activator from Agkistrodon blomhoffii Ussurensis venom (ABUSV-PA): Purification and characterization  

International Nuclear Information System (INIS)

[en] A plasminogen activator with arginine ester hydrolysis activity (ABUSV-PA) has been identified and purified to homogeneity from Chinese Agkistrodon blomhoffii Ussurensis snake venom. ABUSV-PA, a monomeric protein with molecular mass of 27815.2 Da, was purified 180-fold with 0.02% recovery for protein and 3.6% recovery for esterase activity. ABUSV-PA reacts optimally with its substrate N ?-tosyl-L-arginine-methyl ester (TAME) at ?pH 7.5 and at 51 oC. Measurement from inductively coupled plasma-atomic emission spectroscopy (ICP-AES) reveals that ABUSV-PA is a Zn2+-containing protein with a stoichiometry of 1:1 [Zn2+]:[ABUSV-PA]. Analyses of esterase hydrolysis and UV absorption and CD spectra indicate that Zn2+ plays an important role in maintaining the structural integrity rather than the esterase activity of ABUSV-PA. Divalent metal ions, including Ca2+, Mg2+, Cu2+, Ni2+, Mn2+, and Co2+, increase the TAME hydrolysis activity of ABUSV-PA. A red-shift of the emission wavelengths of the synchronous fluorescence of ABUSV-PA, compared to those of free Tyr and Trp, indicates a conformation where the Tyr and Trp residues are in exposed hydrophilic environments. The presence of zinc increases the hydrophobicity of the conformational environments surrounding the Trp residues of ABUSV-PA and affects the secondary structure of ABUSV-PA, as proved by UV absorption and CD spectroscopy

2006-10-06

259

Modulation of staphylokinase-dependent plasminogen activation by mono- and divalent ions  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of several ions (Cl-, Na+, K+, Ca2+) on the rate of plasminogen (Pg) activation by recombinant staphylokinase (rSTA) is reported. Both monovalent and divalent ions affect the rate at which Pg is activated by rSTA, in a concentration-dependent manner (range 0-100 mM). In almost all cases, a decrease of the initial velocity of activation was observed. Cl- showed the most striking inhibitory effect at low concentrations (64% at 10 mM). However, in the presence of a fibrin surface, this inhibition was attenuated to 38%. Surprisingly, 10 mM Ca2+ enhanced the Pg activation rate 21% when a polymerized fibrin matrix was present. These data support the idea that ions can modulate the rate of Pg activation through a mechanism that may be associated with changes in the molecular conformation of the zymogen. This effect is strongly dependent on the presence of a fibrin clot.

Yarzábal A.; Serrano R.L.; Puig J.

1999-01-01

260

Modulation of staphylokinase-dependent plasminogen activation by mono- and divalent ions  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The effect of several ions (Cl-, Na+, K+, Ca2+) on the rate of plasminogen (Pg) activation by recombinant staphylokinase (rSTA) is reported. Both monovalent and divalent ions affect the rate at which Pg is activated by rSTA, in a concentration-dependent manner (range 0-100 mM). In almost all cases, a decrease of the initial velocity of activation was observed. Cl- showed the most striking inhibitory effect at low concentrations (64% at 10 mM). However, in the presence of (more) a fibrin surface, this inhibition was attenuated to 38%. Surprisingly, 10 mM Ca2+ enhanced the Pg activation rate 21% when a polymerized fibrin matrix was present. These data support the idea that ions can modulate the rate of Pg activation through a mechanism that may be associated with changes in the molecular conformation of the zymogen. This effect is strongly dependent on the presence of a fibrin clot.

Yarzábal, A.; Serrano, R.L.; Puig, J.

1999-01-01

 
 
 
 
261

Enhanced plasminogen activation by staphylokinase in the presence of streptokinase beta/betagamma domains: plasminogen kringles play a role.  

UK PubMed Central (United Kingdom)

Presence of isolated beta or betagamma domains of streptokinase (SK) increased the catalytic activity of staphylokinase (SAK)-plasmin (Pm) complex up to 60%. In contrast, fusion of SK beta or betagamma domains with the C-terminal end of SAK drastically reduced the catalytic activity of the activator complex. The enhancement effect mediated by beta or betagamma domain on Pg activator activity of SAK-Pm complex was reduced greatly (45%) in the presence of isolated kringles of Pg, whereas, kringles did not change cofactor activity of SAK fusion proteins (carrying beta or betagamma domains) significantly. When catalytic activity of SAK-microPm (catalytic domain of Pm lacking kringle domains) complex was examined in the presence of isolated beta and betagamma domains, no enhancement effect on Pg activation was observed, whereas, enzyme complex formed between microplasmin and SAK fusion proteins (SAKbeta and SAKbetagamma) displayed 50-70% reduction in their catalytic activity. The present study, thus, suggests that the exogenously present beta and betagamma interact with Pg/Pm via kringle domains and elevate catalytic activity of SAK-Pm activator complex resulting in enhanced substrate Pg activation. Fusion of beta or betagamma domains with SAK might alter these intermolecular interactions resulting in attenuated functional activity of SAK.

Dahiya M; Rajamohan G; Dikshit KL

2005-03-01

262

Enhanced plasminogen activation by staphylokinase in the presence of streptokinase beta/betagamma domains: plasminogen kringles play a role.  

Science.gov (United States)

Presence of isolated beta or betagamma domains of streptokinase (SK) increased the catalytic activity of staphylokinase (SAK)-plasmin (Pm) complex up to 60%. In contrast, fusion of SK beta or betagamma domains with the C-terminal end of SAK drastically reduced the catalytic activity of the activator complex. The enhancement effect mediated by beta or betagamma domain on Pg activator activity of SAK-Pm complex was reduced greatly (45%) in the presence of isolated kringles of Pg, whereas, kringles did not change cofactor activity of SAK fusion proteins (carrying beta or betagamma domains) significantly. When catalytic activity of SAK-microPm (catalytic domain of Pm lacking kringle domains) complex was examined in the presence of isolated beta and betagamma domains, no enhancement effect on Pg activation was observed, whereas, enzyme complex formed between microplasmin and SAK fusion proteins (SAKbeta and SAKbetagamma) displayed 50-70% reduction in their catalytic activity. The present study, thus, suggests that the exogenously present beta and betagamma interact with Pg/Pm via kringle domains and elevate catalytic activity of SAK-Pm activator complex resulting in enhanced substrate Pg activation. Fusion of beta or betagamma domains with SAK might alter these intermolecular interactions resulting in attenuated functional activity of SAK. PMID:15757642

Dahiya, Monika; Rajamohan, G; Dikshit, Kanak L

2005-03-14

263

Fibrin selectivity of the isolated protease domains of tissue-type and vampire bat salivary gland plasminogen activators.  

Science.gov (United States)

The activity of vampire bat (Desmodus rotundus) salivary plasminogen activator (D. rotundus PA alpha1) and to a much lesser extent of tissue-type plasminogen activator (t-PA) is stimulated by the presence of fibrin. This cofactor requirement has in the past intuitively been attributed to fibrin binding. We have previously shown that elements of the non-protease domain of D. rotundus PA alpha1 could contribute to fibrin stimulation irrespective of fibrin binding. We now demonstrate that the protease domain of D. rotundus PA alpha1 by itself exhibits fibrin selectivity, i.e. it is 32-fold stimulated by fibrin but only 1.5-fold by fibrinogen. To a lesser extent this fibrin selectivity is also shared by the protease domain of t-PA. Our findings indicate that protein-protein interactions apart from fibrin binding affect the stimulatory mechanism of fibrin on D. rotundus PA alpha1 and t-PA. PMID:9523718

Toschi, L; Bringmann, P; Petri, T; Donner, P; Schleuning, W D

1998-02-15

264

Binding and activation of host plasminogen on the surface of Francisella tularensis  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Francisella tularensis (FT) is a gram-negative facultative intracellular coccobacillus and is the causal agent of a life-threatening zoonotic disease known as tularemia. Although FT preferentially infects phagocytic cells of the host, recent evidence suggests that a significant number of bacteria can be found extracellularly in the plasma fraction of the blood during active infection. This observation suggests that the interaction between FT and host plasma components may play an important role in survival and dissemination of the bacterium during the course of infection. Plasminogen (PLG) is a protein zymogen that is found in abundance in the blood of mammalian hosts. A number of both gram-positive and gram-negative bacterial pathogens have the ability to bind to PLG, giving them a survival advantage by increasing their ability to penetrate extracellular matrices and cross tissue barriers. Results We show that PLG binds to the surface of FT and that surface-bound PLG can be activated to plasmin in the presence of tissue PLG activator in vitro. In addition, using Far-Western blotting assays coupled with proteomic analyses of FT outer membrane preparations, we have identified several putative PLG-binding proteins of FT. Conclusions The ability of FT to acquire surface bound PLG that can be activated on its surface may be an important virulence mechanism that results in an increase in initial infectivity, survival, and/or dissemination of this bacterium in vivo.

Clinton Shawn R; Bina James E; Hatch Thomas P; Whitt Michael A; Miller Mark A

2010-01-01

265

Targeted delivery of tissue plasminogen activator by binding to silica-coated magnetic nanoparticle  

Directory of Open Access Journals (Sweden)

Full Text Available Jyh-Ping Chen,1 Pei-Ching Yang,1 Yunn-Hwa Ma,2 Su-Ju Tu,3 Yu-Jen Lu1,41Department of Chemical and Materials Engineering, 2Department of Physiology and Pharmacology, 3Department of Medical Imaging and Radiological Sciences, Chang Gung University, Kwei-San, Taoyuan, Taiwan, Republic of China; 4Department of Neurosurgery, Chang Gung Memorial Hospital, Kwei-San, Taoyuan, Taiwan, Republic of ChinaBackground and methods: Silica-coated magnetic nanoparticle (SiO2-MNP) prepared by the sol-gel method was studied as a nanocarrier for targeted delivery of tissue plasminogen activator (tPA). The nanocarrier consists of a superparamagnetic iron oxide core and an SiO2 shell and is characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, superconducting quantum interference device, and thermogravimetric analysis. An amine-terminated surface silanizing agent (3-aminopropyltrimethoxysilane) was used to functionalize the SiO2 surface, which provides abundant —NH2 functional groups for conjugating with tPA.Results: The optimum drug loading is reached when 0.5 mg/mL tPA is conjugated with 5 mg SiO2-MNP where 94% tPA is attached to the carrier with 86% retention of amidolytic activity and full retention of fibrinolytic activity. In vitro biocompatibility determined by lactate dehydrogenase release and cell proliferation indicated that SiO2-MNP does not elicit cytotoxicity. Hematological analysis of blood samples withdrawn from mice after venous administration indicates that tPA-conjugated SiO2-MNP (SiO2-MNP-tPA) did not alter blood component concentrations. After conjugating to SiO2-MNP, tPA showed enhanced storage stability in buffer and operation stability in whole blood up to 9.5 and 2.8-fold, respectively. Effective thrombolysis with SiO2-MNP-tPA under magnetic guidance is demonstrated in an ex vivo thrombolysis model where 34% and 40% reductions in blood clot lysis time were observed compared with runs without magnetic targeting and with free tPA, respectively, using the same drug dosage. Enhanced penetration of SiO2-MNP-tPA into blood clots under magnetic guidance was confirmed from microcomputed tomography analysis.Conclusion: Biocompatible SiO2-MNP developed in this study will be useful as a magnetic targeting drug carrier to improve clinical thrombolytic therapy.Keywords: magnetic nanoparticles, drug delivery, thrombolysis, tissue plasminogen activator, silica

Chen JP; Yang PC; Ma YH; Tu SJ; Lu YJ

2012-01-01

266

Stimulation of plasminogen activation by recombinant cellular prion protein is conserved in the NH2-terminal fragment PrP23-110.  

Science.gov (United States)

The cellular prion protein (PrP(c)), tissue-type plasminogen activator (t-PA) and plasminogen are expressed in synaptic membranes in vivo. In the central nervous system the fibrinolytic system is associated with excitotoxin-mediated neurotoxicity and Alzheimer's disease. Recently binding of the disease associated isoform of the prion protein (PrP(Sc)) to plasminogen and stimulation of t-PA activity have been reported. In this study the interaction of PrP(c) and plasminogen was investigated using chromogenic assays in vitro. We found that plasmin is able to cleave recombinant PrP(c) at lysine residue 110 generating an NH(2)-terminal truncated molecule that has previously been described as a major product of PrP(c) metabolism. We further characterized the proteolytic fragments with respect to their ability to stimulate plasminogen activation in vitro. Our results show that the NH(2)-terminal part of PrP(c) spanning amino acids 23-110 (PrP23-110) together with low molecular weight heparin stimulates t-PA mediated plasminogen activation in vitro. The apparent rate constant was increased 57 fold in the presence of 800 nM PrP23-110. Furthermore, we compared the stimulation of t-PA activity by PrP(c) and beta-amyloid peptide (1-42). While the activity of the beta-amyloid was independent of low molecular weight heparin, PrP23-110 was approximately 4- and 37 fold more active than beta-amyloid in the absence or presence of low molecular weight heparin. In summary, plasmin cleaves PrP(c) in vitro and the liberated NH(2)-terminal fragment accelerates plasminogen activation. Cleavage of PrP c has previously been reported. Thus cleavage of PrP(c) enhancing plasminogen activation at the cell surface could constitute a regulatory mechanism of pericellular proteolysis. PMID:12719777

Praus, Michael; Kettelgerdes, Gerhard; Baier, Michael; Holzhütter, Hermann-Georg; Jungblut, Peter R; Maissen, Manuela; Epple, Guido; Schleuning, Wolf-Dieter; Köttgen, Eckart; Aguzzi, Adriano; Gessner, Reinhard

2003-05-01

267

Transforming Growth Factor-Beta and Urokinase-Type Plasminogen Activator: Dangerous Partners in Tumorigenesis--Implications in Skin Cancer  

Science.gov (United States)

Transforming growth factor-beta (TGF-?) is a pleiotropic factor, with several different roles in health and disease. TGF-? has been postulated as a dual factor in tumor progression, since it represses epithelial tumor development in early stages, whereas it stimulates tumor progression in advanced stages. During tumorigenesis, cancer cells acquire the capacity to migrate and invade surrounding tissues and to metastasize different organs. The urokinase-type plasminogen activator (uPA) system, comprising uPA, the uPA cell surface receptor, and plasminogen-plasmin, is involved in the proteolytic degradation of the extracellular matrix and regulates key cellular events by activating intracellular signal pathways, which together allow cancer cells to survive, thus, enhancing cell malignance during tumor progression. Due to their importance, uPA and its receptor are tightly transcriptionally regulated in normal development, but are deregulated in cancer, when their activity and expression are related to further development of cancer. TGF-? regulates uPA expression in cancer cells, while uPA, by plasminogen activation, may activate the secreted latent TGF-?, thus, producing a pernicious cycle which contributes to the enhancement of tumor progression. Here we review the specific roles and the interplay between TGF-? and uPA system in cancer cells and their implication in skin cancer.

Santibanez, Juan F.

2013-01-01

268

Transforming growth factor-Beta and urokinase-type plasminogen activator: dangerous partners in tumorigenesis-implications in skin cancer.  

UK PubMed Central (United Kingdom)

Transforming growth factor-beta (TGF- ? ) is a pleiotropic factor, with several different roles in health and disease. TGF- ? has been postulated as a dual factor in tumor progression, since it represses epithelial tumor development in early stages, whereas it stimulates tumor progression in advanced stages. During tumorigenesis, cancer cells acquire the capacity to migrate and invade surrounding tissues and to metastasize different organs. The urokinase-type plasminogen activator (uPA) system, comprising uPA, the uPA cell surface receptor, and plasminogen-plasmin, is involved in the proteolytic degradation of the extracellular matrix and regulates key cellular events by activating intracellular signal pathways, which together allow cancer cells to survive, thus, enhancing cell malignance during tumor progression. Due to their importance, uPA and its receptor are tightly transcriptionally regulated in normal development, but are deregulated in cancer, when their activity and expression are related to further development of cancer. TGF- ? regulates uPA expression in cancer cells, while uPA, by plasminogen activation, may activate the secreted latent TGF- ? , thus, producing a pernicious cycle which contributes to the enhancement of tumor progression. Here we review the specific roles and the interplay between TGF- ? and uPA system in cancer cells and their implication in skin cancer.

Santibanez JF

2013-01-01

269

Inhibitory effect of interferon-gamma activated ovine umbilical vein endothelial cells on the intracellular replication of Toxoplasma gondii.  

Science.gov (United States)

Toxoplasma gondii is an obligate intracellular parasite that is a major cause of abortion and neonatal mortality in sheep. In congenital toxoplasmosis, T gondii first invades the umbilical vein endothelial cells and are then disseminated throughout the fetus. Treatment of ovine umbilical vein endothelial cells with bovine recombinant gamma-interferon (IFN-gamma) blocked the growth of T gondii. Growth of the parasite was measured by 3H-uracil incorporation 18 h after the onset of the infection and by microscopic enumeration of parallel cultures. This assay revealed that when the cells were pretreated with IFN-gamma in concentrations ranging from 0.15-1,250 U/mL, a high degree of inhibition of T gondii replication was observed with the effect being dose-dependent. Maximum activation was achieved by incubating with 625 U/mL IFN-gamma and no activity was present at 0.15 U/mL. This technique could be of relevance as a first line of defense against congenital ovine Toxoplasma infection. Inhibition of T gondii replication is due to a different mechanism from that existing in mouse macrophages and human fibroblasts. L-Arginine-dependent production of reactive nitrogen and oxygen intermediates was not responsible for the inhibition of T gondii replication. Supplements of five amino acids were able to overcome the inhibition partially but significantly. The mechanism of the inhibition remains to be elucidated. PMID:8822620

Dimier, I H; Bout, D T

1996-01-01

270

Inhibitory effect of interferon-gamma activated ovine umbilical vein endothelial cells on the intracellular replication of Toxoplasma gondii.  

UK PubMed Central (United Kingdom)

Toxoplasma gondii is an obligate intracellular parasite that is a major cause of abortion and neonatal mortality in sheep. In congenital toxoplasmosis, T gondii first invades the umbilical vein endothelial cells and are then disseminated throughout the fetus. Treatment of ovine umbilical vein endothelial cells with bovine recombinant gamma-interferon (IFN-gamma) blocked the growth of T gondii. Growth of the parasite was measured by 3H-uracil incorporation 18 h after the onset of the infection and by microscopic enumeration of parallel cultures. This assay revealed that when the cells were pretreated with IFN-gamma in concentrations ranging from 0.15-1,250 U/mL, a high degree of inhibition of T gondii replication was observed with the effect being dose-dependent. Maximum activation was achieved by incubating with 625 U/mL IFN-gamma and no activity was present at 0.15 U/mL. This technique could be of relevance as a first line of defense against congenital ovine Toxoplasma infection. Inhibition of T gondii replication is due to a different mechanism from that existing in mouse macrophages and human fibroblasts. L-Arginine-dependent production of reactive nitrogen and oxygen intermediates was not responsible for the inhibition of T gondii replication. Supplements of five amino acids were able to overcome the inhibition partially but significantly. The mechanism of the inhibition remains to be elucidated.

Dimier IH; Bout DT

1996-01-01

271

Simvastatin suppresses dexamethasone-induced secretion of plasminogen activator inhibitor-1 in human bone marrow adipocytes  

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Full Text Available Abstract Background Osteonecrosis of the femoral head is a common complication of high-dose glucocorticoid treatment. Intravascular thrombosis is thought to be associated with the ischemic state of the femoral head. Plasminogen activator inhibitor-1 (PAI-1) is an adipokine, which are physiologically active substances secreted from visceral and subcutaneous adipocytes. PAI-1 suppresses fibrinolysis by binding tissue-type plasminogen activator. Several reports have described the relationship between PAI-1 and steroid-induced osteonecrosis of the femoral head, and the preventive effects of lipid-lowering agents (statins) against steroid-induced osteonecrosis of the femoral head. We previously reported that adipokines and dexamethasone induced PAI-1 secretion from bone marrow adipocytes. The purpose of the present study is to examine the effects of simvastatin on PAI-1 secretion from human bone marrow adipocytes in vitro. Methods Primary bone marrow adipocytes were extracted from collagenase-treated bone marrow fluid obtained from the femoral necks of 40 patients (6 men, 34 women; age range, 52-81 years) undergoing hip joint replacement surgery. After suspended culture with or without dexamethasone or simvastatin, PAI-1 mRNA expression was assessed by real-time RT-PCR. Total PAI-1 protein secretion in culture medium was assessed by enzyme-linked immunosorbent assay. Results PAI-1 mRNA expression was up-regulated by 388% (P = 0.002) with dexamethasone, and down-regulated by 45% (P = 0.002) with simvastatin, as compared to control levels. Dexamethasone increased total PAI-1 secretion by 166% (P = 0.001) and simvastatin decreased total PAI-1 secretion by 64% (P = 0.002). No significant changes were observed in adiponectin mRNA expression and secretion by dexamethasone and simvastatin, while pre-treatment with simvastatin reversed dexamethasone induced PAI-1 secretion by 89%, as compared to control levels. Conclusion The present study confirmed the suppressive effects of simvastatin on PAI-1 expression and secretion from bone marrow adipocytes. Furthermore, pre-treatment with simvastatin reversed dexamethasone induced PAI-1 secretion. Simvastatin may thus exhibit preventive effects against steroid-induced osteonecrosis of the femoral head by suppressing PAI-1 secretion.

Sakamoto Kazutaka; Osaki Makoto; Hozumi Akira; Goto Hisataka; Fukushima Tatsuya; Baba Hideo; Shindo Hiroyuki

2011-01-01

272

The thermostability of natural variants of bacterial plasminogen-activator staphylokinase.  

UK PubMed Central (United Kingdom)

Three natural variants (wild-type staphylokinase, [R36G, R43H]staphylokinase, and [G34S, R36G, R43H]staphylokinase) of the bacterial plasminogen-activator staphylokinase, a 136-amino-acid protein secreted by certain Staphylococcus aureus strains, have been characterized. These variants differ at amino acid positions 34, 36 and 43 only, and have a very similar plasminogen-activating capacity and conformation in solution, as revealed by fluorescence spectroscopy, dynamic light scattering and circular dichroism. However, the thermostability of these variants is significantly different. At 70 degrees C and 0.5 mg protein/ml, irreversible inactivation occurred with apparent half-life (t1/2) values 0.54 +/- 0.13, 0.81 +/- 0.20 and 3.7 +/- 0.7 h (mean +/- SEM) for wild-type staphylokinase, [R36G, R43H]staphylokinase, and [G34S, R36G, R43H]staphylokinase, respectively, with corresponding values at 0.08 mg/ml of 5.3 +/- 1.4 h and 11 +/- 2.0 h for wild-type staphylokinase and [R36G, R43H]staphylokinase, respectively. Dynamic light-scattering measurements indicated that inactivation was associated with protein aggregation, which precluded accurate determination of transition temperatures and enthalpies of unfolding. 0.08-0.34 mg/ml [G34S, R36G, R43H]staphylokinase, however, did not aggregate at 70 degrees C but underwent unfolding as revealed by a 20% increase in the Stokes' radius and a 30% decrease in circular dichroism. The unfolding was reversible upon cooling and was associated with full recovery of functional activity. Thus, these natural variants of staphylokinase have a different sensitivity to thermal inactivation, that is mediated by reversible unfolding of the protein and concentration-dependent irreversible aggregation. [G34S, R36G, R43H]staphylokinase, the most resistant natural variant, has a stability approaching the minimal requirements for pasteurization, which would facilitate its development for clinical use.

Gase A; Birch-Hirschfeld E; Gührs KH; Hartmann M; Vetterman S; Damaschun G; Damaschun H; Gast K; Misselwitz R; Zirwer D

1994-07-01

273

Bioconjugation of recombinant tissue plasminogen activator to magnetic nanocarriers for targeted thrombolysis  

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Full Text Available Hung-Wei Yang,1,* Mu-Yi Hua,1,* Kun-Ju Lin,2,* Shiaw-Pyng Wey,3 Rung-Ywan Tsai,4 Siao-Yun Wu,5 Yi-Ching Lu,5 Hao-Li Liu,6 Tony Wu,7 Yunn-Hwa Ma5 1Chang Gung Molecular Medicine Research Center, Department of Chemical and Materials Engineering, 2Molecular Imaging Center, Department of Nuclear Medicine, Chang Gung Memorial Hospital, Kuei-Shan, Tao-Yuan, Taiwan, Republic of China; 3Department of Medical Imaging and Radiological Sciences, 4Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsin-chu, Taiwan, Republic of China; 5Department of Physiology and Pharmacology and Healthy Aging Research Center, 6Department of Electrical Engineering, Chang Gung University, Kuei-Shan, Tao-Yuan, Taiwan, Republic of China; 7Department of Neurology, Chang Gung University College of Medicine and Memorial Hospital, Tao-Yuan, Taiwan, Republic of China*These authors contributed equally to this workAbstract: Low-toxicity magnetic nanocarriers (MNCs) composed of a shell of poly [aniline-co-N-(1-one-butyric acid) aniline] over a Fe3O4 magnetic nanoparticle core were developed to carry recombinant tissue plasminogen activator (rtPA) in MNC-rtPA for targeted thrombolysis. With an average diameter of 14.8 nm, the MNCs exerted superparamagnetic properties. Up to 276 µg of active rtPA was immobilized per mg of MNCs, and the stability of the immobilized rtPA was greatly improved during storage at 4°C and 25°C. In vitro thrombolysis testing with a tubing system demonstrated that magnet-guided MNC-rtPA showed significantly improved thrombolysis compared with free rtPA and reduced the clot lysis time from 39.2 ± 3.2 minutes to 10.8 ± 4.2 minutes. In addition, magnet-guided MNC-rtPA at 20% of the regular rtPA dose restored blood flow within 15–25 minutes of treatment in a rat embolism model without triggering hematological toxicity. In conclusion, this improved system is based on magnetic targeting accelerated thrombolysis and is potentially amenable to therapeutic applications in thromboembolic diseases.Keywords: thrombolysis, recombinant tissue plasminogen activator, magnetic nanocarriers, magnetic targeting, targeting therapy

Yang HW; Hua MY; Lin KJ; Wey SP; Tsai RY; Wu SY; Lu YC; Liu HL; Wu T; Ma YH

2012-01-01

274

A Plasminogen Activator Inhibitor-1 Inhibitor Reduces Airway Remodeling in a Murine Model of Chronic Asthma  

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We previously reported that plasminogen activator inhibitor (PAI)-1 deficiency prevents collagen deposition in the airways of ovalbumin (OVA)-challenged mice. In this study, we explored the therapeutic utility of blocking PAI-1 in preventing airway remodeling, using a specific PAI-1 inhibitor, tiplaxtinin. C57BL/6J mice were immunized with intraperitoneal injections of OVA on Days 0, 3, and 6. Starting on Day 11, mice were challenged with phosphate-buffered saline or OVA by nebulization three times per week for 4 weeks. Tiplaxtinin was mixed with chow and administered orally from 1 day before the phosphate-buffered saline or OVA challenge. Lung tissues were harvested after challenge and characterized histologically for infiltrating inflammatory cells, mucus-secreting goblet cells, and collagen deposition. Airway hyperresponsiveness was measured using whole-body plethysmography. Tiplaxtinin treatment significantly decreased levels of PAI-1 activity in bronchoalveolar lavage fluids, which indicates successful blockage of PAI-1 activity in the airways. The number of infiltrated inflammatory cells was reduced by tiplaxtinin treatment in the lungs of the OVA-challenged mice. Furthermore, oral administration of tiplaxtinin significantly attenuated the degree of goblet cell hyperplasia and collagen deposition in the airways of the OVA-challenged mice, and methacholine-induced airway hyperresponsiveness was effectively reduced by tiplaxtinin in these animals. This study supports our previous findings that PAI-1 promotes airway remodeling in a murine model of chronic asthma, and suggests that PAI-1 may be a novel target of treatment of airway remodeling in asthma.

Lee, Sun H.; Eren, Mesut; Vaughan, Douglas E.; Schleimer, Robert P.

2012-01-01

275

Tissue Plasminogen Activator Alters Intracellular Sequestration of Zinc through Interaction with the Transporter ZIP4  

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Glutamatergic neurons contain free zinc packaged into neurotransmitter-loaded synaptic vesicles. Upon neuronal activation, the vesicular contents are released into the synaptic space, whereby the zinc modulates activity of postsynaptic neurons though interactions with receptors, transporters and exchangers. However, high extracellular concentrations of zinc trigger seizures and are neurotoxic if substantial amounts of zinc reenter the cells via ion channels and accumulate in the cytoplasm. Tissue plasminogen activator (tPA), a secreted serine protease, is also proepileptic and excitotoxic. However, tPA counters zinc toxicity by promoting zinc import back into the neurons in a sequestered form that is nontoxic. Here, we identify the zinc influx transporter, ZIP4, as the pathway through which tPA mediates the zinc uptake. We show that ZIP4 is upregulated after excitotoxin stimulation of the mouse, male and female, hippocampus. ZIP4 physically interacts with tPA, correlating with an increased intracellular zinc influx and lysosomal sequestration. Changes in prosurvival signals support the idea that this sequestration results in neuroprotection. These experiments identify a mechanism via which neurons use tPA to efficiently neutralize the toxic effects of excessive concentrations of free zinc.

Emmetsberger, Jaime; Mirrione, Martine M.; Zhou, Chun; Fernandez-Monreal, Monica; Siddiq, Mustafa M.; Ji, Kyungmin; Tsirka, Stella E. (SBU)

2010-09-17

276

Diverse inhibition of plasminogen activator inhibitor type 1 by theaflavins of black tea.  

Science.gov (United States)

Fruits, vegetables, spices and a variety of teas are suggested for the prevention of many diseases. They encompass active, non-nutritional ingredients called nutraceuticals which are defined as food products that provide health benefits. Many nutraceuticals have been tested to identify inhibitors of plasminogen activator inhibitor (PAI-1). PAI-1 is the major and fast acting physiological inhibitor of fibrinolysis. However, preclinical studies of PAI-1 inhibitors have revealed an additional role of PAI-1 in the pathogenesis of vascular remodeling, renal injury, diabetes, obesity, Alzheimer's disease and cancer. Thus PAI-1 is a potential therapeutic target in some of these diseases. Our previous study revealed that a black tea extract (containing mostly theaflavins) inhibits PAI-1. In this study we report results for four pure (>98%) theaflavins. Inactivation of PAI-1 was tested by clot formation and by its lysis using thromboelastometry and measurements of human plasma turbidity. Among four tested theaflavins, theaflavin-3'-gallate was the most potent in PAI-1 inhibition trailed by theaflavin-3,3'-digallate, while the other two i.e., theaflavin and theaflavin-3-gallate did not show inhibitory activity. PMID:21308350

Jankun, Jerzy; Skotnicka, Magdalena; ?ysiak-Szyd?owska, Wies?awa; Al-Senaidy, Abdulrahman; Skrzypczak-Jankun, Ewa

2011-02-09

277

Diverse inhibition of plasminogen activator inhibitor type 1 by theaflavins of black tea.  

UK PubMed Central (United Kingdom)

Fruits, vegetables, spices and a variety of teas are suggested for the prevention of many diseases. They encompass active, non-nutritional ingredients called nutraceuticals which are defined as food products that provide health benefits. Many nutraceuticals have been tested to identify inhibitors of plasminogen activator inhibitor (PAI-1). PAI-1 is the major and fast acting physiological inhibitor of fibrinolysis. However, preclinical studies of PAI-1 inhibitors have revealed an additional role of PAI-1 in the pathogenesis of vascular remodeling, renal injury, diabetes, obesity, Alzheimer's disease and cancer. Thus PAI-1 is a potential therapeutic target in some of these diseases. Our previous study revealed that a black tea extract (containing mostly theaflavins) inhibits PAI-1. In this study we report results for four pure (>98%) theaflavins. Inactivation of PAI-1 was tested by clot formation and by its lysis using thromboelastometry and measurements of human plasma turbidity. Among four tested theaflavins, theaflavin-3'-gallate was the most potent in PAI-1 inhibition trailed by theaflavin-3,3'-digallate, while the other two i.e., theaflavin and theaflavin-3-gallate did not show inhibitory activity.

Jankun J; Skotnicka M; ?ysiak-Szyd?owska W; Al-Senaidy A; Skrzypczak-Jankun E

2011-04-01

278

Activation of plasminogen by staphylokinase reduces the severity of Staphylococcus aureus systemic infection.  

UK PubMed Central (United Kingdom)

BACKGROUND: Staphylokinase (SAK) is produced by the majority of Staphylococcus aureus strains. It is an extracellular protein that activates the conversion of human plasminogen (plg) to plasmin. The role played by SAK in staphylococcal infection is unclear. METHODS: Wild-type S. aureus strain LS-1, which lacks the ability to produce SAK, was modified by an insertion of the sak gene into its chromosome. The sak gene was integrated in 2 forms--(1) linked to its own promoter and (2) fused to the promoter of the protein A gene--which resulted in the overexpression of SAK. SAK is highly specific for human plg and exhibits almost no activity toward murine plg. To investigate the role played by SAK in a murine infection model, human plg transgenic mice and their wild-type counterparts were inoculated intravenously with congenic S. aureus strains differing in SAK production. RESULTS: Human plg transgenic mice inoculated with SAK-expressing strains displayed significantly reduced mortality, less weight loss, and lower bacterial loads in kidneys than did the wild-type mice. No difference in the severity of sepsis was observed between transgenic and wild-type mice infected with a SAK-deficient strain. CONCLUSIONS: The results suggest that expression of SAK followed by activation of plg alleviates the course of S. aureus sepsis.

Kwieci?ski J; Josefsson E; Mitchell J; Higgins J; Magnusson M; Foster T; Jin T; Bokarewa M

2010-10-01

279

Pharmacological and clinical impact of the unique molecular structure of a new plasminogen activator.  

UK PubMed Central (United Kingdom)

Thrombolytic therapy has been recognized as a significant improvement in the management of acute myocardial infarction. Thrombolytic agents however have been limited by short half-lives that necessitate complex administration protocols and by the potential for bleeding complications. The native t-PA molecule has since been modified in an attempt to achieve improved lytic characteristics with less risk of bleeding. Reteplase is a third-generation recombinant mutant of tissue-type plasminogen activator (t-PA) that is expressed in Escherichia coli cells and consists of the kringle 2 and the protease domains of t-PA. Compared with t-PA, reteplase has a lower fibrin binding, which may translate to improved clot penetration. As well as a longer half-life and a more rapid initiation of thrombolysis. Preclinical pharmacology studies have indicated that reteplase has potent in vivo thrombolytic activity and leads to rapid reperfusion; these findings have been confirmed by promising results obtained in large-scale clinical trials. Other new agents developed by modifying the native t-PA molecule include the n-PA and the TNK mutants of t-PA. These novel, genetically modified thrombolytic agents all lyse clots better than the native t-PA; however, they differ with respect to their half-lives and fibrin-binding activity. Although all the third-generation thrombolytic agents have shown considerable potential in improving the efficacy of thrombolytic therapy, their risk of intracranial bleeding remains problematic and is still somewhat uncertain.

Smalling RW

1997-12-01

280

5-Fluorouracil-induced Leukoencephalopathy with Acute Stroke-like Presentation Fulfilling Criteria for Recombinant Tissue Plasminogen Activator Therapy.  

UK PubMed Central (United Kingdom)

A 61-year-old man underwent systemic chemotherapy with intravenous infusion of nedaplatin and 5-fluorouracil. On the day after the final drug administration, he suddenly experienced difficulty in speaking followed by left-sided weakness. His National Institutes of Health Stroke Scale score was 12. A computed tomographic scan of the brain performed 4 hours after symptom onset revealed no abnormalities. Because all eligibility criteria were fulfilled, he immediately underwent intravenous recombinant tissue plasminogen activator therapy. He recovered from neurologic complications on day 14. An initial magnetic resonance imaging scan of his brain revealed a hyperintense area in the bilateral white matter and corpus callosum, and these abnormalities had improved on the follow-up scan. We diagnosed him with 5-fluorouracil-induced leukoencephalopathy with acute stroke-like presentation. Our experience suggests that 5-fluorouracil-induced leukoencephalopathy potentially fulfills all eligibility criteria for recombinant tissue plasminogen activator therapy.

Kinno R; Kii Y; Uchiyama M; Owan Y; Yamazaki T; Fukui T

2013-02-01

 
 
 
 
281

Cell surface-bound urokinase-type plasminogen activator facilitates infiltration of freshly isolated granulocytes into fibrin matrix.  

Science.gov (United States)

Human cell lines of myelo/monocytic origin express the cellular receptor for urokinase-type plasminogen activator (uPA-R). The receptor localizes urokinase-type plasminogen activator (uPA) to the surface of the cell, where it can convert plasminogen to the active serine proteinase plasmin. Plasmin may subsequently account for proteolysis of pericellular proteins. We demonstrated the expression of the uPA-R by freshly isolated neutrophilic granulocytes by using a specific mAb. In freshly isolated granulocytes we detected only a weak occupation of the uPA-R; further uPA binding by granulocytes was saturable and proceeded in a dose-dependent manner. Receptor-bound uPA retained its enzymatic activity. Saturation of isolated granulocytes with exogenous uPA enhanced cellular infiltration into a fibrin matrix in vitro. uPA-dependent infiltration was inhibited by an anti-catalytic monoclonal anti-uPA antibody. The findings show that circulating neutrophilic granulocytes express the cell surface uPA-R and suggest that surface-binding of uPA may facilitate the infiltration of granulocytes into a fibrin clot, a process that might add to thrombolysis in vivo. PMID:8749230

Herijgers, N; Vettel, U; Schaefer, B; Spring, H; Todd, R F; Kramer, M D

1995-11-01

282

The estrogen-regulated 52 K protein adn plasminogen activators released by MCF7 cells are different.  

UK PubMed Central (United Kingdom)

In the MCF7 human breast cancer cell line, estradiol stimulates the synthesis of a 52 K secretory glycoprotein and has been reported to increase the plasminogen activator (PA) activity in the culture medium. Since one PA isozyme has a molecular weight close to 52 000 daltons under denaturing conditions, we asked whether the 52 K protein was a PA. The PA activity released in serum-free conditioned medium was evaluated by the increase in [125I]casein digestion observed in the presence of plasminogen. The 52 K protein was estimated by analysing the released proteins on SDS-polyacrylamide gel electrophoresis. When the conditioned medium was chromatographed on concanavalin A-Sepharose, the 52 K protein was retained on the gel, but not the PA. The two proteins also appeared different on the basis of their competing efficiency in a radioimmunoassay developed to quantify the 52 K protein. An antiserum against human urokinase failed to immunoprecipitate the 52 K protein. Under our culture conditions estradiol increased 52 K, but not PA, production. These results clearly indicate that the estradiol-regulated 52 K protein is not a plasminogen activator.

Massot O; Capony F; Garcia M; Rochefort H

1984-05-01

283

Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells  

Science.gov (United States)

Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient management when combined with MRI and drug delivery.Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient management when combined with MRI and drug delivery. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr32922d

Hansen, Line; Unmack Larsen, Esben Kjær; Nielsen, Erik Holm; Iversen, Frank; Liu, Zhuo; Thomsen, Karen; Pedersen, Michael; Skrydstrup, Troels; Nielsen, Niels Chr.; Ploug, Michael; Kjems, Jørgen

2013-08-01

284

Cloning and Expression of a Human Tissue Plasminogen Activator Variant:K2S in Escherichia coli  

Directory of Open Access Journals (Sweden)

Full Text Available The DNA sequence of Kringle-2 and serine protease domains of the human tissue plasminogen activator (reteplase, K2S) was PCR amplified. This product was then cloned into the expression vector pET15b plasmid. The presence of the insert was confirmed by restriction digestion, PCR and determination of the nucleotide sequence. By using isopropyl ?-D thiogalactopyranoside (IPTG), reteplase was induced in E. coli BL21 cells and analyzed using polyacrylamide gel electrophoresis (PAGE).

Hamid Mir Mohammad Sadeghi; Kianoush Dormiani; Yahya Khazaie; Mohammad Rabbani; Fatemeh Moazen

2007-01-01

285

Infusion of recombinant human tissue plasminogen activator through the superior mesenteric artery in the treatment of acute mesenteric venous thrombosis.  

Science.gov (United States)

Acute mesenteric venous thrombosis is an uncommon condition that is usually treated with systemic anticoagulation. Catheter-directed thrombolysis through the superior mesenteric artery may be a viable adjunct to treat this morbid condition. In the present article, we have described a case of superior mesenteric venous thrombosis treated with catheter-directed infusion of tissue plasminogen activator through the superior mesenteric artery. PMID:21620665

da Motta Leal Filho, Joaquim Mauricio; Santos, Aline Cristine Barbosa; Carnevale, Francisco Cesar; de Oliveira Sousa, Wilson; Grillo, Luiz Sérgio Pereira; Cerri, Giovanni Guido

2011-05-28

286

Plasminogen is a complement inhibitor.  

Science.gov (United States)

Plasminogen is a 92-kDa single chain glycoprotein that circulates in plasma as a zymogen and when converted to proteolytically active plasmin dissolves preformed fibrin clots and extracellular matrix components. Here, we characterize the role of plasmin(ogen) in the complement cascade. Plasminogen binds the central complement protein C3, the C3 cleavage products C3b and C3d, and C5. Plasminogen binds to C3, C3b, C3d, and C5 via lysine residues, and the interaction is ionic strength-dependent. Plasminogen and Factor H bind C3b; however, the two proteins bind to different sites and do not compete for binding. Plasminogen affects complement action in multiple ways. Plasminogen enhanced Factor I-mediated C3b degradation in the presence of the cofactor Factor H. Plasminogen when activated to plasmin inhibited complement as demonstrated by hemolytic assays using either rabbit or sheep erythrocytes. Similarly, plasmin either in the fluid phase or attached to surfaces inhibited complement that was activated via the alternative and classical pathways and cleaved C3b to fragments of 68, 40, 30, and 17 kDa. The C3b fragments generated by plasmin differ in size from those generated by the complement protease Factor I, suggesting that plasmin-mediated C3b cleavage fragments lack effector function. Plasmin also cleaved C5 to products of 65, 50, 30, and 25 kDa. Thus, plasmin(ogen) regulates both complement and coagulation, the two central cascade systems of a vertebrate organism. This complement-inhibitory activity of plasmin provides a new explanation why pathogenic microbes utilize plasmin(ogen) for immune evasion and tissue penetration. PMID:22451663

Barthel, Diana; Schindler, Susann; Zipfel, Peter F

2012-03-27

287

Plasminogen Is a Complement Inhibitor*  

Science.gov (United States)

Plasminogen is a 92-kDa single chain glycoprotein that circulates in plasma as a zymogen and when converted to proteolytically active plasmin dissolves preformed fibrin clots and extracellular matrix components. Here, we characterize the role of plasmin(ogen) in the complement cascade. Plasminogen binds the central complement protein C3, the C3 cleavage products C3b and C3d, and C5. Plasminogen binds to C3, C3b, C3d, and C5 via lysine residues, and the interaction is ionic strength-dependent. Plasminogen and Factor H bind C3b; however, the two proteins bind to different sites and do not compete for binding. Plasminogen affects complement action in multiple ways. Plasminogen enhanced Factor I-mediated C3b degradation in the presence of the cofactor Factor H. Plasminogen when activated to plasmin inhibited complement as demonstrated by hemolytic assays using either rabbit or sheep erythrocytes. Similarly, plasmin either in the fluid phase or attached to surfaces inhibited complement that was activated via the alternative and classical pathways and cleaved C3b to fragments of 68, 40, 30, and 17 kDa. The C3b fragments generated by plasmin differ in size from those generated by the complement protease Factor I, suggesting that plasmin-mediated C3b cleavage fragments lack effector function. Plasmin also cleaved C5 to products of 65, 50, 30, and 25 kDa. Thus, plasmin(ogen) regulates both complement and coagulation, the two central cascade systems of a vertebrate organism. This complement-inhibitory activity of plasmin provides a new explanation why pathogenic microbes utilize plasmin(ogen) for immune evasion and tissue penetration.

Barthel, Diana; Schindler, Susann; Zipfel, Peter F.

2012-01-01

288

Plasminogen is a complement inhibitor.  

UK PubMed Central (United Kingdom)

Plasminogen is a 92-kDa single chain glycoprotein that circulates in plasma as a zymogen and when converted to proteolytically active plasmin dissolves preformed fibrin clots and extracellular matrix components. Here, we characterize the role of plasmin(ogen) in the complement cascade. Plasminogen binds the central complement protein C3, the C3 cleavage products C3b and C3d, and C5. Plasminogen binds to C3, C3b, C3d, and C5 via lysine residues, and the interaction is ionic strength-dependent. Plasminogen and Factor H bind C3b; however, the two proteins bind to different sites and do not compete for binding. Plasminogen affects complement action in multiple ways. Plasminogen enhanced Factor I-mediated C3b degradation in the presence of the cofactor Factor H. Plasminogen when activated to plasmin inhibited complement as demonstrated by hemolytic assays using either rabbit or sheep erythrocytes. Similarly, plasmin either in the fluid phase or attached to surfaces inhibited complement that was activated via the alternative and classical pathways and cleaved C3b to fragments of 68, 40, 30, and 17 kDa. The C3b fragments generated by plasmin differ in size from those generated by the complement protease Factor I, suggesting that plasmin-mediated C3b cleavage fragments lack effector function. Plasmin also cleaved C5 to products of 65, 50, 30, and 25 kDa. Thus, plasmin(ogen) regulates both complement and coagulation, the two central cascade systems of a vertebrate organism. This complement-inhibitory activity of plasmin provides a new explanation why pathogenic microbes utilize plasmin(ogen) for immune evasion and tissue penetration.

Barthel D; Schindler S; Zipfel PF

2012-05-01

289

Bioconjugation of recombinant tissue plasminogen activator to magnetic nanocarriers for targeted thrombolysis.  

UK PubMed Central (United Kingdom)

Low-toxicity magnetic nanocarriers (MNCs) composed of a shell of poly [aniline-co-N-(1-one-butyric acid) aniline] over a Fe(3)O(4) magnetic nanoparticle core were developed to carry recombinant tissue plasminogen activator (rtPA) in MNC-rtPA for targeted thrombolysis. With an average diameter of 14.8 nm, the MNCs exerted superparamagnetic properties. Up to 276 ?g of active rtPA was immobilized per mg of MNCs, and the stability of the immobilized rtPA was greatly improved during storage at 4°C and 25°C. In vitro thrombolysis testing with a tubing system demonstrated that magnet-guided MNC-rtPA showed significantly improved thrombolysis compared with free rtPA and reduced the clot lysis time from 39.2 ± 3.2 minutes to 10.8 ± 4.2 minutes. In addition, magnet-guided MNC-rtPA at 20% of the regular rtPA dose restored blood flow within 15-25 minutes of treatment in a rat embolism model without triggering hematological toxicity. In conclusion, this improved system is based on magnetic targeting accelerated thrombolysis and is potentially amenable to therapeutic applications in thromboembolic diseases.

Yang HW; Hua MY; Lin KJ; Wey SP; Tsai RY; Wu SY; Lu YC; Liu HL; Wu T; Ma YH

2012-01-01

290

Bioconjugation of recombinant tissue plasminogen activator to magnetic nanocarriers for targeted thrombolysis.  

Science.gov (United States)

Low-toxicity magnetic nanocarriers (MNCs) composed of a shell of poly [aniline-co-N-(1-one-butyric acid) aniline] over a Fe(3)O(4) magnetic nanoparticle core were developed to carry recombinant tissue plasminogen activator (rtPA) in MNC-rtPA for targeted thrombolysis. With an average diameter of 14.8 nm, the MNCs exerted superparamagnetic properties. Up to 276 ?g of active rtPA was immobilized per mg of MNCs, and the stability of the immobilized rtPA was greatly improved during storage at 4°C and 25°C. In vitro thrombolysis testing with a tubing system demonstrated that magnet-guided MNC-rtPA showed significantly improved thrombolysis compared with free rtPA and reduced the clot lysis time from 39.2 ± 3.2 minutes to 10.8 ± 4.2 minutes. In addition, magnet-guided MNC-rtPA at 20% of the regular rtPA dose restored blood flow within 15-25 minutes of treatment in a rat embolism model without triggering hematological toxicity. In conclusion, this improved system is based on magnetic targeting accelerated thrombolysis and is potentially amenable to therapeutic applications in thromboembolic diseases. PMID:23055728

Yang, Hung-Wei; Hua, Mu-Yi; Lin, Kun-Ju; Wey, Shiaw-Pyng; Tsai, Rung-Ywan; Wu, Siao-Yun; Lu, Yi-Ching; Liu, Hao-Li; Wu, Tony; Ma, Yunn-Hwa

2012-10-01

291

Hepatitis B virus inhibits liver regeneration via epigenetic regulation of urokinase-type plasminogen activator.  

UK PubMed Central (United Kingdom)

Liver regeneration after liver damage caused by toxins and pathogens is critical for liver homeostasis. Retardation of liver proliferation was reported in hepatitis B virus (HBV) X protein (HBx)-transgenic mice. However, the underlying mechanism of the HBx-mediated disturbance of liver regeneration is unknown. We investigated the molecular mechanism of the inhibition of liver regeneration using liver cell lines and a mouse model. The mouse model of acute HBV infection was established by hydrodynamic injection of viral DNA. Liver regeneration after partial hepatectomy was significantly inhibited in the HBV DNA-treated mice. Mechanism studies have revealed that the expression of urokinase-type plasminogen activator (uPA), which regulates the activation of hepatocyte growth factor (HGF), was significantly decreased in the liver tissues of HBV or HBx-expressing mice. The down-regulation of uPA was further confirmed using liver cell lines transiently or stably transfected with HBx and the HBV genome. HBx suppressed uPA expression through the epigenetic regulation of the uPA promoter in mouse liver tissues and human liver cell lines. Expression of HBx strongly induced hypermethylation of the uPA promoter by recruiting DNA methyltransferase (DNMT) 3A2. Conclusion: Taken together, these results suggest that infection of HBV impairs liver regeneration through the epigenetic dysregulation of liver regeneration signals by HBx.

Park ES; Park YK; Shin CY; Park SH; Ahn SH; Kim DH; Lim KH; Kwon SY; Kim KP; Yang SI; Seong BL; Kim KH

2013-08-01

292

Significant inverse associations of serum n-6 fatty acids with plasma plasminogen activator inhibitor-1.  

UK PubMed Central (United Kingdom)

Epidemiological studies suggested that n-6 fatty acids, especially linoleic acid (LA), have beneficial effects on CHD, whereas some in vitro studies have suggested that n-6 fatty acids, specifically arachidonic acid (AA), may have harmful effects. We examined the association of serum n-6 fatty acids with plasminogen activator inhibitor-1 (PAI-1). A population-based cross-sectional study recruited 926 randomly selected men aged 40-49 years without CVD during 2002-2006 (310 Caucasian, 313 Japanese and 303 Japanese-American men). Plasma PAI-1 was analysed in free form, both active and latent. Serum fatty acids were measured with gas-capillary liquid chromatography. To examine the association between total n-6 fatty acids (including LA and AA) and PAI-1, multivariate regression models were used. After adjusting for confounders, total n-6 fatty acids, LA and AA, were inversely and significantly associated with PAI-1 levels. These associations were consistent across three populations. Among 915 middle-aged men, serum n-6 fatty acids had significant inverse associations with PAI-1.

Lee S; Curb JD; Kadowaki T; Evans RW; Miura K; Takamiya T; Shin C; El-Saed A; Choo J; Fujiyoshi A; Otake T; Kadowaki S; Seto T; Masaki K; Edmundowicz D; Ueshima H; Kuller LH; Sekikawa A

2012-02-01

293

Late results of catheter-directed recombinant tissue plasminogen activator fibrinolytic therapy of iliofemoral deep venous thrombosis.  

UK PubMed Central (United Kingdom)

PURPOSE: To evaluate the efficacy of catheter-directed low-dose recombinant tissue-type plasminogen activator infusion in the treatment of iliofemoral deep venous thrombosis and prevention of post-thrombotic syndrome. METHOD: Eighteen patients (out of 260 evaluated) with acute iliofemoral deep venous thrombosis and no previous evidence of venous insufficiency were prospectively selected for thrombolytic therapy. Catheter-directed low-dose recombinant tissue-type plasminogen activator (1 mg/h) was infused into the thrombotic segments. RESULTS: Effective fibrinolysis was achieved in 14 of 18 cases, with correlation between effective fibrinolysis and major/complete resolution of acute signs and symptoms (P <.01). There were no episodes of major complications. Four patients presented with early rethrombosis (1 to 8 weeks). Individuals were followed for a period up to 131 weeks (average, 85.2). The incidence of clinical signs and symptoms of venous insufficiency and duplex-scan findings of valvular reflux was significantly lower in the patients in which lytic therapy succeeded and patency was kept, compared with patients experiencing acute therapeutic failure or rethrombosis (P <.01). CONCLUSIONS: Low-dose recombinant tissue-type plasminogen activator fibrinolytic therapy is safe and effective in the treatment of acute iliofemoral venous thrombosis. The late evolution as revealed clinically and by ultrasound was superior in patients for whom lytic therapy was effective.

Casella IB; Presti C; Aun R; Benabou JE; Puech-Leão P

2007-02-01

294

Soluble urokinase plasminogen activator receptor levels reflect organ damage in systemic lupus erythematosus.  

Science.gov (United States)

Assessments of disease activity and organ damage in systemic lupus erythematosus (SLE) remain challenging because of the lack of reliable biomarkers and disease heterogeneity. Ongoing inflammation can be difficult to distinguish from permanent organ damage caused by previous flare-ups or medication side effects. Circulating soluble urokinase plasminogen activator receptor (suPAR) has emerged as a potential marker of inflammation and disease severity, and an outcome predictor in several disparate conditions. This study was done to evaluate suPAR as a marker of disease activity and organ damage in SLE. Sera from 100 healthy donors and 198 patients with SLE fulfilling the 1982 American College of Rheumatology classification criteria and/or the Fries criteria were analyzed for suPAR by enzyme immunoassay. Eighteen patients with varying degree of disease activity were monitored longitudinally. Disease activity was assessed by the SLE disease activity index 2000 and the physician's global assessment. Organ damage was evaluated by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology damage index (SDI). Compared with healthy control subjects, serum suPAR levels were elevated significantly in patients with SLE. No association was recorded regarding suPAR levels and SLE disease activity in cross-sectional or consecutive samples. However, a strong association was observed between suPAR and SDI (P < 0.0005). Considering distinct SDI domains, renal, neuropsychiatric, ocular, skin, and peripheral vascular damage had a significant effect on suPAR levels. This study is the first to demonstrate an association between serum suPAR and irreversible organ damage in SLE. Further studies are warranted to evaluate suPAR and other biomarkers as predictors of evolving organ damage. PMID:23916811

Enocsson, Helena; Wetterö, Jonas; Skogh, Thomas; Sjöwall, Christopher

2013-08-01

295

Glucose deprivation reversibly down-regulates tissue plasminogen activator via proteasomal degradation in rat primary astrocytes.  

UK PubMed Central (United Kingdom)

AIMS: Tissue plasminogen activator (tPA) is an essential neuromodulator whose involvement in multiple functions such as synaptic plasticity, cytokine-like immune function and regulation of cell survival mandates rapid and tight tPA regulation in the brain. We investigated the possibility that a transient metabolic challenge induced by glucose deprivation may affect tPA activity in rat primary astrocytes, the main cell type responsible for metabolic regulation in the CNS. MAIN METHODS: Rat primary astrocytes were incubated in serum-free DMEM without glucose. Casein zymography was used to determine tPA activity, and tPA mRNA was measured by RT-PCR. The signaling pathways regulating tPA activity were identified by Western blotting. KEY FINDINGS: Glucose deprivation rapidly down-regulated the activity of tPA without affecting its mRNA level in rat primary astrocytes; this effect was mimicked by translational inhibitors. The down-regulation of tPA was accompanied by increased tPA degradation, which may be modulated by a proteasome-dependent degradation pathway. Glucose deprivation induced activation of PI3K-Akt-GSK3?, p38 and AMPK, and inhibition of these pathways using LY294002, SB203580 and compound C significantly inhibited glucose deprivation-induced tPA down-regulation, demonstrating the essential role of these pathways in tPA regulation in glucose-deprived astrocytes. SIGNIFICANCE: Rapid and reversible regulation of tPA activity in rat primary astrocytes during metabolic crisis may minimize energy-requiring neurologic processes in stressed situations. This effect may thereby increase the opportunity to invest cellular resources in cell survival and may allow rapid re-establishment of normal cellular function after the crisis.

Cho KS; Joo SH; Choi CS; Kim KC; Ko HM; Park JH; Kim P; Hur J; Lee SH; Bahn GH; Ryu JH; Lee J; Han SH; Kwon KJ; Shin CY

2013-05-01

296

Plasminogen activator inhibitor-1 4G/5G polymorphism is associated with type 2 diabetes risk.  

Science.gov (United States)

A number of studies were performed to assess the association between plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism and susceptibility to type 2 diabetes (T2DM). However, the results were inconsistent and inconclusive. In the present study, the possible association was investigated by a meta-analysis. Eligible articles were identified for the period up to June 2013. Pooled odds ratios (OR) with 95% confidence intervals (CI) were appropriately derived from random-effects models or fixed-effects models. Fourteen case-control studies with a total of 2487 cases and 3538 controls were eligible. In recessive model, PAI-1 4G/5G polymorphism was associated with T2DM risk (OR = 1.23; 95% CI 1.07-1.41; P = 0.004). In the subgroup analysis by ethnicity, a significant association was found among Asians (OR = 1.27; 95% CI 1.08-1.51; P = 0.005). This meta-analysis suggested that PAI-1 4G/5G polymorphism may be associated with T2DM development. PMID:24040470

Zhao, Luqian; Huang, Ping

2013-09-01

297

Erythrocyte-bound tissue plasminogen activator is neuroprotective in experimental traumatic brain injury.  

UK PubMed Central (United Kingdom)

The purpose of this study was to test the effects of exogenous tissue plasminogen activator (tPA) in traumatic brain injury (TBI).We tested two different tPA formulations, free tPA and tPA bound to erythrocytes (RBC/tPA).Vehicle and each of the tPA treatments were injected intravenously into anesthetized rats 15 min after moderate lateral fluid percussion injury. The animals were sacrificed at 2 days for calculating microclot burden (n=13) and IgG staining area (n=13) in the brain sections as indicators of post-traumatic thrombosis and blood-brain barrier (BBB) breakdown, respectively. Another set of injured animals treated in the same way were sacrificed at 7 days to compare cortical lesion volumes (n=28) and CA3 hippocampal cell loss (n=24). All evaluations were done blinded with respect to treatment. No significant differences were found with respect to microclot burden or IgG staining volume. Injection of wild-type tPA caused significantly ( p<0.05) larger cortical injuries and greater cerebral hemorrhage. In contrast, there was significantly less cortical injury ( p<0.01) and hippocampal cell loss ( p<0.01) in the RBC=tPA group than in all other groups. These results reveal that RBC/tPA is more neuroprotective in experimental TBI than is unbound tPA.

Stein SC; Ganguly K; Belfield CM; Xu X; Swanson EW; Chen XH; Browne KD; Johnson VE; Smith DH; LeBold DG; Cines DB; Muzykantov VR; Muzykhantov VR

2009-09-01

298

Erythrocyte-Bound Tissue Plasminogen Activator is Neuroprotective in Experimental Traumatic Brain Injury  

Science.gov (United States)

Abstract The purpose of this study was to test the effects of exogenous tissue plasminogen activator (tPA) in traumatic brain injury (TBI). We tested two different tPA formulations, free tPA and tPA bound to erythrocytes (RBC/tPA). Vehicle and each of the tPA treatments were injected intravenously into anesthetized rats 15?min after moderate lateral fluid percussion injury. The animals were sacrificed at 2 days for calculating microclot burden (n?=?13) and IgG staining area (n?=?13) in the brain sections as indicators of post-traumatic thrombosis and blood–brain barrier (BBB) breakdown, respectively. Another set of injured animals treated in the same way were sacrificed at 7 days to compare cortical lesion volumes (n?=?28) and CA3 hippocampal cell loss (n?=?24). All evaluations were done blinded with respect to treatment. No significant differences were found with respect to microclot burden or IgG staining volume. Injection of wild-type tPA caused significantly (p?

Ganguly, Kumkum; Belfield, Caitlin M.; Xu, Xiangsheng; Swanson, Edward W.; Chen, Xiao-Han; Browne, Kevin D.; Johnson, Victoria E.; Smith, Douglas H.; LeBold, David G.; Cines, Douglas B.; Muzykantov, Vladimir R.

2009-01-01

299

Are free fatty acids related to plasma plasminogen activator inhibitor 1 in android obesity?  

Science.gov (United States)

Plasminogen activator inhibitor 1 (PAI-1) levels are elevated in obese insulin-resistant subjects. However the mechanism underlying increased PAI-1 levels is unknown. To determine the impact of diabetes on PAI-1 levels and its possible relationship to insulin resistance, hyperinsulinemic euglycemic clamp studies were performed in nine lean control subjects, nine non-diabetic obese subjects and eight obese patients with NIDDM. Fasting plasma PAI-1 levels were 4.0 to 4.7 fold higher in the two obese groups than in the control group. During the 40 mU/m2 x min insulin infusion, suppression of FFA concentration was correlated with fasting plasma PAI-1 levels in both obese non-diabetic and obese NIDDM subjects. It is concluded that (1) obesity rather than diabetes itself plays a major role for the increased PAI-1 levels in NIDDM; (2) resistance to the antilipolytic effect of insulin, resulting in increased FFA concentrations, may participate in producing elevated PAI-1 levels in android obese subjects. PMID:8589788

Bastard, J P; Bruckert, E; Robert, J J; Ankri, A; Grimaldi, A; Jardel, C; Hainque, B

1995-11-01

300

Are free fatty acids related to plasma plasminogen activator inhibitor 1 in android obesity?  

UK PubMed Central (United Kingdom)

Plasminogen activator inhibitor 1 (PAI-1) levels are elevated in obese insulin-resistant subjects. However the mechanism underlying increased PAI-1 levels is unknown. To determine the impact of diabetes on PAI-1 levels and its possible relationship to insulin resistance, hyperinsulinemic euglycemic clamp studies were performed in nine lean control subjects, nine non-diabetic obese subjects and eight obese patients with NIDDM. Fasting plasma PAI-1 levels were 4.0 to 4.7 fold higher in the two obese groups than in the control group. During the 40 mU/m2 x min insulin infusion, suppression of FFA concentration was correlated with fasting plasma PAI-1 levels in both obese non-diabetic and obese NIDDM subjects. It is concluded that (1) obesity rather than diabetes itself plays a major role for the increased PAI-1 levels in NIDDM; (2) resistance to the antilipolytic effect of insulin, resulting in increased FFA concentrations, may participate in producing elevated PAI-1 levels in android obese subjects.

Bastard JP; Bruckert E; Robert JJ; Ankri A; Grimaldi A; Jardel C; Hainque B

1995-11-01

 
 
 
 
301

Steroids and plasminogen activator concentrations in follicular fluid of gilts at first and third estrus.  

Science.gov (United States)

An experiment was conducted to determine whether morphological and functional characteristics of follicles differed at a similar stage of pubertal (first) and third estrus in the same gilts. Nine prepubertal gilts were checked three times daily for estrus and laparotomized 6 h after detected first and third estrus. Samples of vena cava and ovarian venous blood were collected, follicle numbers and diameters were recorded, and follicular fluid (FF) was aspirated from all follicles 8 to 12 mm in diameter. Sera and(or) FF were analyzed for progesterone (P4), estradiol-17 beta (E2), testosterone (T), androstenedione (A4), 5 alpha-dihydrotestosterone (DHT), plasminogen activator (PA), and plasmin (PLM). Overall mean number of follicles > or = 8 mm in diameter did not differ between gilts at first and third estrus (P > .05) but gilts at first estrus had more follicles 4 to 8 (P .05). Mean concentrations of E2 in systemic and ovarian venous sera were also greater in gilts at third than at first estrus (both P .05).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1474022

Smith, G D; Menino, A R; Rowe, K E; Stormshak, F

1992-12-01

302

Bicyclic Peptide Inhibitor of Urokinase-Type Plasminogen Activator : Mode of Action  

DEFF Research Database (Denmark)

The development of protease inhibitors for pharmacological intervention has taken a new turn with the use of peptidebased inhibitors. Here, we report the rational design of bicyclic peptide inhibitors of the serine protease urokinase-type plasminogen activator (uPA), based on the established monocyclic peptide, upain-2. It was successfully converted to a bicyclic peptide, without loss of inhibitory properties. The aim was to produce a peptide cyclised by an amide bond with an additional stabilising across-the-ring covalent bond. We expected this bicyclic peptide to exhibit a lower entropic burden upon binding. Two bicyclic peptides were synthesised with affinities similar to that of upain-2, and their binding energetics were evaluated by isothermal titration calorimetry. Indeed, compared to upain-2, the bicyclic peptides showed reduced loss of entropy upon binding to uPA. We also investigated the solution structures of the bicyclic peptide by NMR spectroscopy to map possible conformations. An X-ray structure of the bicyclicpeptide– uPA complex confirmed an interaction similar to that for the previous upain-1/upain-2–uPA complexes. These physical studies of the peptide–protease interactions will aid future designs of bicyclic peptide protease inhibitors

Roodbeen, Renée; Paaske, Berit

2013-01-01

303

Induction of plasminogen activator by UV light in normal and xeroderma pigmentosum fibroblasts  

Energy Technology Data Exchange (ETDEWEB)

Normal and DNA repair-deficient human fibroblasts have been used to study induction of plasminogen activator (PA) by DNA damage. UV light induced the synthesis of PA in skin fibroblasts of all types of xeroderma pigmentosum (XP) in XP heterozygotes and in human amniotic cells. Enzyme induction was, however, not observed in fibroblasts of normal adults. In classical XP, which are deficient in excision repair, PA synthesis occurred in a narrow range of low-UV fluences. In such strains, the level of enzyme produced was correlated with the extent of repair deficiency. UV fluences required for PA induction in XP variants and XP heteozygotes were at least 10 times those inducing enzyme synthesis in excision-deficient XP. Maximum enzyme induction occurred 48 hr after irradiation, and the highest levels of enzyme produced were 15-20 times those of PA baseline levels. Electrophoretic analysis showed that UV irradiation enhances the synthesis of the M/sub r/ 60,000 human urokinase-type PA, which is present in low amounts in untreated cells. Our results suggest that PA induction in human cells is caused by unrepaired DNA damage and represents a eukaryotic SOS-like function. In addition, PA induction may provide a sensitive assay for detection of cellular DNA repair deficiencies and identification of XP heterozygotes.

Miskin, R. (Weizmann Inst. of Science, Rehovot, Israel); Ben-Ishai, R.

1981-10-01

304

The urokinase plasminogen activator and its inhibitors PAI-1 and PAI-2 in primary cutaneous melanoma  

International Nuclear Information System (INIS)

Background. We investigated the differences in urokinase plasminogen activator (uPA) and its inhibitors type1 and 2 (PAI-1/2) concentrations in clinically suspected nevi, primary cutaneous melanoma and normal skin and correlations with histopathological prognostic factors of primary melanoma. Patients and methods. Fifty-one patients were enrolled. The tissue concentrations of uPA, PAI-1 and PAI- 2 were quantified by enzyme-linked immunosorbent assay (ELISA). Results. Mean uPA and PAI-1 concentrations in melanomas were higher than in normal surrounding skin (uPA: 1.08; vs. 0.48 ng/mgp; PAI-1: 14.07 vs. 2.07 ng/mgp; p 0.05; PAI-1: p = 0.02). PAI-2 concentration was higher in normal surrounding skin than in nevi and melanomas (p > 0.05). Melanoma uPA, PAI-1 and PAI-2 concentrations correlated significantly with normal skin (r = 0.73, 0.54, 0.38 respectively). PAI-1 was significantly lower in melanomas of Breslow thickness ? 0.75 mm, Clark invasion of 0+I, without microscopic ulceration, without vascular invasion (p 0.75 mm, Clark invasion > II, with ulceration and vascular invasion. Conclusions. Determination of uPA and PAI-1 can provide significant additional prognostic information for melanoma patients. (author)

2003-01-01

305

TFRC and ACTB as the best reference genes to quantify Urokinase Plasminogen Activator in breast cancer  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Biomedical researchers have long looked for ways to diagnose and treat cancer patients at the early stages through biomarkers. Although conventional techniques are routinely applied in the detection of biomarkers, attitudes towards using Real-Time PCR techniques in detection of many biomarkers are increasing. Normalization of quantitative Real-Time PCR is necessary to validate non-biological alteration occurring during the steps of RNA quantification. Selection of variably expressed housekeeping genes (HKs) will affect the validity of the data. The aim of the present study was to identify uniformly expressed housekeeping genes in order to use in the breast cancer gene expression studies. Urokinase Plasminogen Activator was used as a gene of interest. Findings The expression of six HKs (TFRC, GUSB, GAPDH, ACTB, HPRT1 and RPLP0) was investigated using geNorm and NormFinder softwares in forty breast tumor, four normal and eight adjacent tissues. RPLP0 and GAPDH revealed maximum M value, while TFRC demonstrated lowest M value. Conclusions In the present study the most and the least stable genes were TFRC and RPLP0 respectively. TFRC and ACTB were verified as the best combination of two genes for breast cancer quantification. The result of this study shows that in each gene expression analysis HKs selection should be done based on experiment conditions.

Majidzadeh-A Keivan; Esmaeili Rezvan; Abdoli Nasrin

2011-01-01

306

Aggregation and retention of human urokinase type plasminogen activator in the yeast endoplasmic reticulum  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Secretion of recombinant proteins in yeast can be affected by their improper folding in the endoplasmic reticulum and subsequent elimination of the misfolded molecules via the endoplasmic reticulum associated protein degradation pathway. Recombinant proteins can also be degraded by the vacuolar protease complex. Human urokinase type plasminogen activator (uPA) is poorly secreted by yeast but the mechanisms interfering with its secretion are largely unknown. Results We show that in Hansenula polymorpha overexpression worsens uPA secretion and stimulates its intracellular aggregation. The absence of the Golgi modifications in accumulated uPA suggests that aggregation occurs within the endoplasmic reticulum. Deletion analysis has shown that the N-terminal domains were responsible for poor uPA secretion and propensity to aggregate. Mutation abolishing N-glycosylation decreased the efficiency of uPA secretion and increased its aggregation degree. Retention of uPA in the endoplasmic reticulum stimulates its aggregation. Conclusions The data obtained demonstrate that defect of uPA secretion in yeast is related to its retention in the endoplasmic reticulum. Accumulation of uPA within the endoplasmic reticulum disturbs its proper folding and leads to formation of high molecular weight aggregates.

Agaphonov Michael O; Romanova Nina V; Trushkina Polina M; Smirnov Vladimir N; Ter-Avanesyan Michael D

2002-01-01

307

Plasma Soluble Urokinase Plasminogen Activator Receptor in Children with Urinary Tract Infection  

Science.gov (United States)

Objective: In this prospective study we investigated the role of plasma levels of soluble urokinase plasminogen activator receptor (suPAR) in children with urinary tract infection. Material and methods: We measured the levels of plasma suPAR during admission in 42 children with suspected acute pyelonephritis and compared the results to acute DMSA scintigraphy. Results: The mean level of plasma suPAR at admission was significantly elevated in children with renal involvement (7.3 ng/ml) assessed by the DMSA scintigraphy compared to children without renal involvement (4.4 ng/ml, P = 0.010). The positive predictive value of suPAR seems high, since all patients without renal involvement had low suPAR values. During treatment the mean level of plasma suPAR decreased. Conclusion: We conclude that plasma suPAR could be of clinical use for the diagnosis of acute pyelonephritis and that high levels of plasma suPAR might reflect the level of renal involvement and could therefore be a new indicator for renal scarring.

Wittenhagen, Per; Andersen, Jesper Brandt; Hansen, Anita; Lindholm, Lone; R?nne, Frederik; Theil, J?rn; Tvede, Michael; Eugen-Olsen, Jesper

2011-01-01

308

Use of aerosolized tissue plasminogen activator in the treatment of plastic bronchitis.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To present a case of nebulized tissue plasminogen activator (t-PA) treatment for symptomatic plastic bronchitis in a pediatric patient years after a Fontan procedure. CASE SUMMARY: A 13-year-old boy with a history of corrected congenital heart disease was admitted to the pediatric intensive care unit after 2 weeks of worsening respiratory distress. A chest radiograph and subsequent bronchoscopy revealed extensive mucus plugging due to plastic bronchitis. Casts reaccumulated quickly after manual removal of the mucus and a regimen of aerosolized t-PA was initiated to break down the casts and prevent further cast formation over the 17-day hospital course. The treatment was successful and the patient was discharged home without evidence of bronchial casts. DISCUSSION: Plastic bronchitis is a potentially devastating condition in which pulmonary infiltrates line the bronchial tree, forming casts and prohibiting effective oxygen exchange. There are few effective treatment options for this condition. The use of aerosolized t-PA for the treatment of plastic bronchitis has been reported to be safe and effective in 4 cases but no consistent regimen, dose, or duration of treatment has been established. CONCLUSIONS: t-PA can be nebulized and inhaled for successful inhibition of bronchial cast formation. More information to determine the most effective dose and duration of therapy is needed to effectively improve the lives of people with plastic bronchitis.

Lubcke NL; Nussbaum VM; Schroth M

2013-03-01

309

Angiotensinogen and Plasminogen Activator Inhibitor-1 Gene Polymorphism in Relation to Renovascular Disease  

International Nuclear Information System (INIS)

The present study was designed to evaluate angiotensinogen (AGT) M235T and plasminogen activator inhibitor-1 (PAI-1) (4G/5G) polymorphisims in relation to the occurrence of atherosclerotic renal artery stenosis (ARAS) and recurrent stenosis. In this study, 30 patients were enrolled after angiographic demonstration of ARAS; 100 healthy subjects for AGT polymorphism and 80 healthy subjects for PAI-1 polymorphism were considered the control group. The patients were followed for a mean 46.1 ± 9.2 months. The patients had significantly higher frequencies of the MT genotype and the T allele than control group (?2 = 18.2, p 2 = 11.5 p 2= 2.45, p = 0.29 and ?2 = 0.019, p = 0.89). There were no significant differences in the genotype and allele findings for the patients with and without restenosis (p > 0.05). The C-reactive protein (CRP) level was higher in the patients with restenosis than in the patients without restenosis (7.694 ± 0.39 mg/L and 1.56 ± 1.08 mg/L) (p = 0.001). Our results suggest that the M235T MT genotype and T allele might be associated with increased risk of atherosclerotic renal artery stenosis. The CRP level might be an independent predictor for recurrent stenosis.

2006-01-01

310

Endogenous tissue type plasminogen activator facilitates NMDA-induced retinal damage  

International Nuclear Information System (INIS)

To investigate the role of tissue plasminogen activator (tPA) in retinal damage, tPA-deficient and wild-type mice were employed. Two different retinal neuron insult models were used in the present study. One is an excitotoxin-treated retinal model, created by direct intravitreal injection of glutamate analogs, NMDA or kainic acid (KA), and the other is an ischemia-reperfusion model induced by transient elevation of intraocular pressure. TdT-dUTP terminal nick-end labeling (TUNEL) method was used to examine the retinal cell nuclear damage. The number of TUNEL-positive cells in ganglion cell layer (GCL) and inner nuclear layer (INL) in tPA-deficient mice after low-, but not high-dose NMDA was significantly less compared to wild type. In contrast, neither intravitreal KA or transient ischemia produced significant difference in retinal damage in tPA vs. wild-type mice. These data show that tPA-deficient mice are resistant to retinal damage by intravitreal injection of NMDA, and indicate that tPA plays a role in the retinal cell damage induced by excitotoxins, especially NMDA.

2004-10-01

311

Fingolimod reduces hemorrhagic transformation associated with delayed tissue plasminogen activator treatment in a mouse thromboembolic model.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: The sphingosine 1-phosphate receptor agonist fingolimod reduces infarct size in rodent models of stroke and enhances blood-brain barrier integrity. Based on these observations, we hypothesized that combination of fingolimod with tissue plasminogen activator (tPA) would reduce the risk of hemorrhagic transformation associated with delayed administration of tPA. METHODS: We evaluated the effects of fingolimod in a mouse model of thromboembolic stroke, in which both the beneficial effect of reperfusion associated with early tPA treatment and hemorrhagic transformation associated with delayed administration mimic clinical observations in humans. RESULTS: Our results demonstrate that fingolimod treatment attenuates the neurological deficit and reduces infarct volume after in situ thromboembolic occlusion of the middle cerebral artery. Combination of fingolimod and tPA improves the neurological outcome of the thrombolytic therapy and reduces the risk of hemorrhagic transformation associated with delayed administration of tPA. CONCLUSIONS: This study confirms the protective efficacy of fingolimod as a treatment against ischemic stroke in another rodent model of stroke (thromboembolic occlusion), and suggests that fingolimod could potentially be used in combination with tPA to reduce the risk of brain hemorrhage.

Campos F; Qin T; Castillo J; Seo JH; Arai K; Lo EH; Waeber C

2013-02-01

312

Binding of tissue plasminogen activator to human umbilical vein endothelial cells  

Energy Technology Data Exchange (ETDEWEB)

The binding of purified, recombinant tissue plasminogen activator (tPA) to human umbilical vein endothelial cells (HUVEC) was studied in vitro using immunofluorescence as well as radiolabeled tPA. Immunofluorescence was performed on HUVEC grown on round glass coverslips using rabbit anti-human tPA and fluorescein-conjugated anti-rabbit immunoglobulin. Positive fluorescence was observed only after incubation of HUVEC with tPA. HUVEC were grown to confluence in 24-well tissue culture plates, washed, and incubated with a constant amount of /sup 125/I-tPA and various concentrations of unlabeled tPA. The binding of tPA to HUVEC was found to be specific, saturable, and reversible. Scatchard analysis yielded as equilibrium constant (K/sub eq/) of 4.2 x 10/sup 6/ M/sup -1/ and 1.2 x 10/sup 7/ binding sites per cell. Binding was inhibited by positively charged amino acids and by D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone but not by carbohydrates including mannose, galactose, N-acetyl glucosamine and N-acetyl galactosamine. Neat human plasma abrogates but does not totally inhibit binding of tPA to HUVEC. Binding was neither enhanced nor inhibited by fibronectin. Although the affinity of binding of tPA to HUVEC is low, the endothelial cell may be involved in regulating plasma levels of tPA in vivo which may have therapeutic significance.

Beebe, D.P.

1987-05-01

313

Tissue plasminogen activator prevents restoration of tight junction proteins through upregulation of angiopoietin-2.  

UK PubMed Central (United Kingdom)

We examined the temporal profiles of changes in the expressions of tight junction proteins (TJPs; namely, claudin-5, occludin, and ZO-1) after focal cerebral ischemia/reperfusion in mice. We also examined the effects of delayed treatment with tissue plasminogen activator (tPA) on the expressions of TJPs and angiopoietin (Ang) -1/2/Tie2. Mice subjected to a 6-h filamental middle cerebral artery (MCA) occlusion were treated with tPA (10 mg/kg, intravenously, just after the start of reperfusion) or vehicle. The expressions of TJPs were significantly decreased in the early phase of ischemia/reperfusion, and then gradually recovered. A delayed treatment with tPA decreased the expressions of TJPs when examined at 42 h after reperfusion. In contrast, delayed tPA treatment markedly increased Ang-2, but not Ang-1 expression, when examined at 30 h after reperfusion. Treatment with tPA at 300 ?g/ml also significantly decreased Ang- 2, but not Tie2 expression, in an in vitro monolayer model generated using human brain microvascular endothelial cells subjected to serum-deprivation. These findings suggest that delayed tPA treatment prevents recovery of TJPs following focal cerebral ischemia/reperfusion, partially via upregulation of Ang-2.

Mishiro K; Ishiguro M; Suzuki Y; Tsuruma K; Shimazawa M; Hara H

2013-02-01

314

Plasminogen activator inhibitor-1 4G/5G polymorphism is associated with type 2 diabetes risk  

Science.gov (United States)

A number of studies were performed to assess the association between plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism and susceptibility to type 2 diabetes (T2DM). However, the results were inconsistent and inconclusive. In the present study, the possible association was investigated by a meta-analysis. Eligible articles were identified for the period up to June 2013. Pooled odds ratios (OR) with 95% confidence intervals (CI) were appropriately derived from random-effects models or fixed-effects models. Fourteen case-control studies with a total of 2487 cases and 3538 controls were eligible. In recessive model, PAI-1 4G/5G polymorphism was associated with T2DM risk (OR = 1.23; 95% CI 1.07-1.41; P = 0.004). In the subgroup analysis by ethnicity, a significant association was found among Asians (OR = 1.27; 95% CI 1.08-1.51; P = 0.005). This meta-analysis suggested that PAI-1 4G/5G polymorphism may be associated with T2DM development.

Zhao, Luqian; Huang, Ping

2013-01-01

315

A human monoclonal antibody scFv to urokinase plasminogen activator.  

Science.gov (United States)

A human monoclonal antibody can be a good method for tumor diagnosis and treatment. This study is aimed at the generation of human antibody fragments against urokinase plasminogen activator (uPA) known to be related to tumor metastasis using the naive human antibody phage display library. Three clones--A2, A8, and E4--were selected from 1 x 10(10) sized human naïve antibody phage library using BIAcore rescue and screen. Clone A8 was finally selected by flow cytometry against Hep3 and HT1080, uPA overexpressing tumor cell lines. A8 clone consisted of 324 bp lambda and 402 bp heavy chains. The affinity (K(D)) of purified A8 antibody fragments was 1.44 x 10(-8) M(-1). The antibody fragment was reacted with HT1080 in a dose-dependent manner but not reacted with LS513 normal fibroblast. In this study, uPA specific human monoclonal antibody fragment A8 was made with BIAcore selection. Selected A8 was bound specifically to uPA expressed on the tumor cell surface. Further study for the application of A8 antibody clones will be needed. PMID:20443707

Bae, Ki-Beom; Jeong, Young-Joo; Won, Hae Jeong; Hong, Kwan-Hee; Choi, Il-Whan; Seo, Su-Kil; Park, Sae-Gwang

2010-04-01

316

A human monoclonal antibody scFv to urokinase plasminogen activator.  

UK PubMed Central (United Kingdom)

A human monoclonal antibody can be a good method for tumor diagnosis and treatment. This study is aimed at the generation of human antibody fragments against urokinase plasminogen activator (uPA) known to be related to tumor metastasis using the naive human antibody phage display library. Three clones--A2, A8, and E4--were selected from 1 x 10(10) sized human naïve antibody phage library using BIAcore rescue and screen. Clone A8 was finally selected by flow cytometry against Hep3 and HT1080, uPA overexpressing tumor cell lines. A8 clone consisted of 324 bp lambda and 402 bp heavy chains. The affinity (K(D)) of purified A8 antibody fragments was 1.44 x 10(-8) M(-1). The antibody fragment was reacted with HT1080 in a dose-dependent manner but not reacted with LS513 normal fibroblast. In this study, uPA specific human monoclonal antibody fragment A8 was made with BIAcore selection. Selected A8 was bound specifically to uPA expressed on the tumor cell surface. Further study for the application of A8 antibody clones will be needed.

Bae KB; Jeong YJ; Won HJ; Hong KH; Choi IW; Seo SK; Park SG

2010-04-01

317

Disulfide pairing of the recombinant kringle-2 domain of tissue plasminogen activator produced in Escherichia coli.  

UK PubMed Central (United Kingdom)

The kringle-2 domain of tissue plasminogen activator, cloned and expressed in Escherichia coli (Wilhelm, O.G., Jaskunas, S.R., Vlahos, C.J., and Bang, N.U. (1990) J. Biol. Chem. 265, 14606-14611), was internally radiolabeled using [35S]methionine-cysteine. Following refolding and isolation, the labeled polypeptide was further purified by reverse-phase high performance liquid chromatography. The purified kringle-2 domain was digested with thermolysin, and the resulting peptides were purified by high performance liquid chromatography. Five major peptides containing 35S were obtained. Amino acid sequence analysis showed that these peptides represented various cleavage products containing one or more of the following disulfides: Cys180-Cys261, Cys201-Cys243, Cys232-Cys256 (sequence numbering based on Pennica et al. (Pennica, D., Holmes, W.E., Kohr, W.J., Hakins, R.N., Vehar, G. A., Ward, C.A., Bennett, W.F., Yelverton E., Seeburg, P.H., Heynecker, H.L., Goeddel, E.V., and Collen, D. (1983) Nature 301, 214-221)). These results confirm that the refolding methodology used produced kringle-2 with the predicted disulfide linkage and, thus, yielded material suitable for structural and functional studies.

Vlahos CJ; Wilhelm OG; Hassell T; Jaskunas SR; Bang NU

1991-06-01

318

Plasminogen activator inhibitor-1 4G/5G polymorphism is associated with type 2 diabetes risk.  

UK PubMed Central (United Kingdom)

A number of studies were performed to assess the association between plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism and susceptibility to type 2 diabetes (T2DM). However, the results were inconsistent and inconclusive. In the present study, the possible association was investigated by a meta-analysis. Eligible articles were identified for the period up to June 2013. Pooled odds ratios (OR) with 95% confidence intervals (CI) were appropriately derived from random-effects models or fixed-effects models. Fourteen case-control studies with a total of 2487 cases and 3538 controls were eligible. In recessive model, PAI-1 4G/5G polymorphism was associated with T2DM risk (OR = 1.23; 95% CI 1.07-1.41; P = 0.004). In the subgroup analysis by ethnicity, a significant association was found among Asians (OR = 1.27; 95% CI 1.08-1.51; P = 0.005). This meta-analysis suggested that PAI-1 4G/5G polymorphism may be associated with T2DM development.

Zhao L; Huang P

2013-01-01

319

Intravitreal tissue plasminogen activator to treat refractory diabetic macular edema by induction of posterior vitreous detachment.  

UK PubMed Central (United Kingdom)

PURPOSE: To evaluate the effects of intravitreal injection of recombinant tissue plasminogen activator (TPA) for the treatment of refractory diabetic macular edema. METHODS: A total of 27 patients with refractory diabetic macular edema with no evidence of posterior vitreous detachment were randomly assigned into follow-up (F/U) or TPA treatment groups. To control for the effects of intravitreal injection, an additional 14 patients with diabetic macular edema who were candidates for first-time intravitreal bevacizumab injection were enrolled as the IVB group. For the TPA and IVB groups, 25 ?g of TPA or 1.25 mg of bevacizumab, respectively, were intravitreally injected. Fundoscopy, optical coherence tomography, and B-scan ultrasonography were performed at 1 week, 1 month, and 3 months after initiation of the study. RESULTS: The incidence of posterior vitreous detachment in fundoscopy over the follow-up period was 69.2% in the TPA group, which was significantly higher than that of the F/U and IVB groups (P = 0.001). Best-corrected visual acuity and changes in macular thickness did not significantly differ between the TPA and F/U groups over the 3-month period. CONCLUSION: Intravitreal TPA injection induces posterior vitreous detachment in patients with diabetic macular edema refractory to standard treatment but has no effect on macular thickness or best-corrected visual acuity within 3 months.

Abrishami M; Moosavi MN; Shoeibi N; Hosseinpoor SS

2011-11-01

320

Targeting of peptide conjugated magnetic nanoparticles to urokinase plasminogen activator receptor (uPAR) expressing cells  

DEFF Research Database (Denmark)

Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are currently being used as a magnetic resonance imaging (MRI) contrast agent in vivo, mainly by their passive accumulation in tissues of interest. However, a higher specificity can ideally be achieved when the nanoparticles are targeted towards cell specific receptors and this may also facilitate specific drug delivery by an enhanced target-mediated endocytosis. We report efficient peptide-mediated targeting of magnetic nanoparticles to cells expressing the urokinase plasminogen activator receptor (uPAR), a surface biomarker for poor patient prognosis shared by several cancers including breast, colorectal, and gastric cancers. Conjugation of a uPAR specific targeting peptide onto polyethylene glycol (PEG) coated USPIO nanoparticles by click chemistry resulted in a five times higher uptake in vitro in a uPAR positive cell line compared to nanoparticles carrying a non-binding control peptide. In accordance with specific receptor-mediated recognition, a low uptake was observed in the presence of an excess of ATF, a natural ligand for uPAR. The uPAR specific magnetic nanoparticles can potentially provide a useful supplement for tumor patient management when combined with MRI and drug delivery.

Hansen, Line; Unmack Larsen, Esben Kjær

2013-01-01

 
 
 
 
321

Plasminogen activator inhibitor-1 predicts coronary in-stent restenosis of drug-eluting stents.  

UK PubMed Central (United Kingdom)

BACKGROUND: We tested the hypothesis that plasma levels of plasminogen activator inhibitor-1 (PAI-1) are influenced by percutaneous coronary intervention (PCI) with the implantation of drug eluting stents (DES) and are able to predict the occurrence of in-stent restenosis (ISR). METHODS AND RESULTS: PAI-1 active antigen plasma levels were determined in 75 patients before and 24 h after PCI with DES implantation. Patients with ISR after six to eight months (16%) showed significantly lower PAI-1 plasma levels before PCI (ISR, 11.7 +/- 8.1 ng mL(-1); non-ISR, 22.8 +/- 18.8 ng mL(-1); P <0.05). PAI-1 levels in the lowest tertile were associated with a 9.5-fold increased risk of ISR, independent of clinical risk factors, angiographic or procedural characteristics, compared to the highest tertile (P < 0.05). The induced change of PAI-1 active antigen 24 h after PCI was significantly higher in patients with ISR (ISR, +5.6 +/- 8.0 ng mL(-1); non-ISR, -3.2 +/- 12.1 ng mL(-1); P < 0.05) with positive correlation to late lumen loss (r = 0.30; P < 0.05). CONCLUSIONS: ISR after DES implantation is significantly related to plasma levels of PAI-1 active antigen before and after PCI. If confirmed by larger multicenter studies, the determination of PAI-1 plasma levels might be clinically helpful in the identification of patients at high risk of developing of ISR, even after DES implantation.

Katsaros KM; Speidl WS; Kastl SP; Zorn G; Huber K; Maurer G; Glogar D; Wojta J; Christ G

2008-03-01

322

The Plasminogen Activation System Modulates Differently Adipogenesis and Myogenesis of Embryonic Stem Cells  

Science.gov (United States)

Regulation of the extracellular matrix (ECM) plays an important functional role either in physiological or pathological conditions. The plasminogen activation (PA) system, comprising the uPA and tPA proteases and their inhibitor PAI-1, is one of the main suppliers of extracellular proteolytic activity contributing to tissue remodeling. Although its function in development is well documented, its precise role in mouse embryonic stem cell (ESC) differentiation in vitro is unknown. We found that the PA system components are expressed at very low levels in undifferentiated ESCs and that upon differentiation uPA activity is detected mainly transiently, whereas tPA activity and PAI-1 protein are maximum in well differentiated cells. Adipocyte formation by ESCs is inhibited by amiloride treatment, a specific uPA inhibitor. Likewise, ESCs expressing ectopic PAI-1 under the control of an inducible expression system display reduced adipogenic capacities after induction of the gene. Furthermore, the adipogenic differentiation capacities of PAI-1?/? induced pluripotent stem cells (iPSCs) are augmented as compared to wt iPSCs. Our results demonstrate that the control of ESC adipogenesis by the PA system correspond to different successive steps from undifferentiated to well differentiated ESCs. Similarly, skeletal myogenesis is decreased by uPA inhibition or PAI-1 overexpression during the terminal step of differentiation. However, interfering with uPA during days 0 to 3 of the differentiation process augments ESC myotube formation. Neither neurogenesis, cardiomyogenesis, endothelial cell nor smooth muscle formation are affected by amiloride or PAI-1 induction. Our results show that the PA system is capable to specifically modulate adipogenesis and skeletal myogenesis of ESCs by successive different molecular mechanisms.

Hadadeh, Ola; Barruet, Emilie; Peiretti, Franck; Verdier, Monique; Bernot, Denis; Hadjal, Yasmine; Yazidi, Claire El; Robaglia-Schlupp, Andree; De Paula, Andre Maues; Negre, Didier; Iacovino, Michelina; Kyba, Michael; Alessi, Marie-Christine; Binetruy, Bernard

2012-01-01

323

Synergy of in vitro thrombolytic action of combinations of recombinant staphylokinase and single-chain urokinase-type plasminogen activator.  

Science.gov (United States)

Kinetics of lysis of human plasma clots immersed in plasma were studied in vitro at 37 degrees C under the influence of recombinant staphylokinase, single-chain urokinase-type plasminogen activator (scu-PA), and their simultaneous and consecutive combinations. Staphylokinase and scu-PA caused concentration- and time-dependent lysis of the clots; 32 nM staphylokinase and 75 nM scu-PA separately caused 50% lysis in 4 h. At these equally effective concentrations staphylokinase in 4 h induced a significantly lesser exhaustion of the plasma plasminogen, alpha(2)-antiplasmin, and fibrinogen than scu-PA. Combinations of staphylokinase (staphylokinase. In 4 h after the addition, staphylokinase (25 nM) or scu-PA (15 nM) induced 24% and 2% lysis, respectively, whereas the simultaneous and consecutive combination of the same concentrations of these agents induced 58% and 50% lysis, respectively. The simultaneous combination of 15 nM staphylokinase and 15 nM scu-PA resulted in maximal 3.8-fold increase in the thrombolytic effect as compared to the expected total effect of the individual agents. Synergic combinations of the two agents caused lesser exhaustion of plasma plasminogen, alpha(2)-antiplasmin, and fibrinogen as compared with the expected total effect of these agents used separately. Thus, simultaneous and consecutive combinations of staphylokinase and scu-PA in a relatively narrow range of their concentrations possessed synergistic fibrin-selective thrombolytic action on the plasma clot in vitro. PMID:14640969

Aisina, R B; Moukhametova, L I; Varfolomeyev, S D

2003-11-01

324

Biochemical mechanism of action of a diketopiperazine inactivator of plasminogen activator inhibitor-1.  

DEFF Research Database (Denmark)

XR5118 [(3 Z,6 Z )-6-benzylidine-3-(5-(2-dimethylaminoethyl-thio-))-2-(thienyl)methylene-2,5-dipiperazinedione hydrochloride] can inactivate the anti-proteolytic activity of the serpin plasminogen activator inhibitor-1 (PAI-1), a potential therapeutic target in cancer and cardiovascular diseases. Serpins inhibit their target proteases by the P(1) residue of their reactive centre loop (RCL) forming an ester bond with the active-site serine residue of the protease, followed by insertion of the RCL into the serpin's large central beta-sheet A. In the present study, we show that the RCL of XR5118-inactivated PAI-1 is inert to reaction with its target proteases and has a decreased susceptibility to non-target proteases, in spite of a generally increased proteolytic susceptibility of specific peptide bonds elsewhere in PAI-1. The properties of XR5118-inactivated PAI-1 were different from those of the so-called latent form of PAI-1. Alanine substitution of several individual residues decreased the susceptibility of PAI-1 to XR5118. The localization of these residues in the three-dimensional structure of PAI-1 suggested that the XR5118-induced inactivating conformational change requires mobility of alpha-helix F, situated above beta-sheet A, and is in agreement with the hypothesis that XR5118 binds laterally to beta-sheet A. These results improve our understanding of the unique conformational flexibility of serpins and the biochemical basis for using PAI-1 as a therapeutic target. Udgivelsesdato: 2003-Aug-1

Einholm, Anja P; Pedersen, Katrine E

2003-01-01

325

Gelsolin induces colorectal tumor cell invasion via modulation of the urokinase-type plasminogen activator cascade.  

UK PubMed Central (United Kingdom)

Gelsolin is a cytoskeletal protein which participates in actin filament dynamics and promotes cell motility and plasticity. Although initially regarded as a tumor suppressor, gelsolin expression in certain tumors correlates with poor prognosis and therapy-resistance. In vitro, gelsolin has anti-apoptotic and pro-migratory functions and is critical for invasion of some types of tumor cells. We found that gelsolin was highly expressed at tumor borders infiltrating into adjacent liver tissues, as examined by immunohistochemistry. Although gelsolin contributes to lamellipodia formation in migrating cells, the mechanisms by which it induces tumor invasion are unclear. Gelsolin's influence on the invasive activity of colorectal cancer cells was investigated using overexpression and small interfering RNA knockdown. We show that gelsolin is required for invasion of colorectal cancer cells through matrigel. Microarray analysis and quantitative PCR indicate that gelsolin overexpression induces the upregulation of invasion-promoting genes in colorectal cancer cells, including the matrix-degrading urokinase-type plasminogen activator (uPA). Conversely, gelsolin knockdown reduces uPA levels, as well as uPA secretion. The enhanced invasiveness of gelsolin-overexpressing cells was attenuated by treatment with function-blocking antibodies to either uPA or its receptor uPAR, indicating that uPA/uPAR activity is crucial for gelsolin-dependent invasion. In summary, our data reveals novel functions of gelsolin in colorectal tumor cell invasion through its modulation of the uPA/uPAR cascade, with potentially important roles in colorectal tumor dissemination to metastatic sites.

Zhuo J; Tan EH; Yan B; Tochhawng L; Jayapal M; Koh S; Tay HK; Maciver SK; Hooi SC; Salto-Tellez M; Kumar AP; Goh YC; Lim YC; Yap CT

2012-01-01

326

[Changes and significance of endogenous tissue plasminogen activators in cerebral hypoxia-ischemia in neonatal rats].  

UK PubMed Central (United Kingdom)

OBJECTIVE: The mechanism of neonatal hypoxic-ischemic brain damage (HIBD) remains unclear and effective treatment approach is limited for this disorder. Many studies have shown that tissue-type plasminogen activator (tPA) plays an important role in nervous system. This study investigated the effect of tPA in HIBD in neonatal rats. METHODS: Seven-day-old Wistar rat pups were used for the Rice-Vannucci model of neonatal hypoxia-ischemia (HI). Brain samples were collected 1, 4, and 24 hrs after HI. FITC-Dextran was injected into the left ventricle of pups after HI to observe reperfusion defects of the neonatal brain. RT-PCR and tPA zymogram were used to detect the expression and activity of tPA. Double immunostaining, terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and DAPI staining were used to detect the expression of integrin GPIIb and fibrin and neuronal apoptosis. RESULTS: FITC-Dextran perfusion analysis indicated there was obvious infarct area in the neonatal brain and the expression of integrin GPIIb and fibrin increased significantly 1 hr after HI compared with the contralateral side. The infarct area decreased and the expression of integrin GPIIb and fibrin were reduced 4 hrs after HI. The expression and activity of tPA increased significantly in neonatal rats after HI, and peaked at 4 hrs after HI. The number of apoptotic neural cells increased progressively with the prolonged reperfusion time following HI. CONCLUSIONS: The increase of tPA in the acute phase after HIBD may be helpful to clot dissolving, but it induces neuronal apoptosis and aggravates brain injury.

Yu D; Mao M; Lei MY

2008-10-01

327

The immune marker soluble urokinase plasminogen activator receptor is associated with new-onset diabetes in non-smoking women and men.  

UK PubMed Central (United Kingdom)

AIM: To explore the putative association of new-onset diabetes and the soluble urokinase plasminogen activator receptor (suPAR), which is a new and stable plasma marker of immune function and low-grade inflammation. This association has been previously suggested by using the less sensitive International Classification of Disease system to detect incident diabetes in the Danish MONICA 10 cohort. METHODS: The Danish National Diabetes Register enabled more accurate identification of incident diabetes during a median follow-up of 13.8 years in the Danish MONICA 10 cohort (n = 2353 generally healthy individuals). The soluble urokinase plasminogen activator receptor was measured by the ELISA method. To fulfil model assumptions, outcome analyses were stratified by age, and further by smoking, owing to the interaction between the soluble urokinase plasminogen activator receptor and smoking on new-onset diabetes (P < 0.0001). RESULTS: New-onset diabetes (n = 182) was associated with increased soluble urokinase plasminogen activator receptor levels (P = 0.013). Among 699 middle-aged (41 and 51 years) and 564 older (61 and 71 years) non-smokers, participants in the upper soluble urokinase plasminogen activator receptor quartile had a sex- and age-adjusted relative risk of 6.01 (95% CI 2.17-16.6, P < 0.0006) and relative risk of 3.25 (95% CI 1.51-6.98, P = 0.0025), respectively, for new-onset diabetes compared with participants in the lowest quartile. This relationship remained significant after additional adjustments for C-reactive protein and leukocytes or fasting glucose and insulin or BMI (P < 0.05). The soluble urokinase plasminogen activator receptor was not related to incident diabetes among smokers (P ? 0.85). CONCLUSIONS: In these explorative analyses, the soluble urokinase plasminogen activator receptor associated independently with incident diabetes in non-smokers, supporting an immune origin of Type 2 diabetes. Competing disease risk may explain lack of association among smokers.

Haugaard SB; Andersen O; Hansen TW; Eugen-Olsen J; Linneberg A; Madsbad S; Olsen MH; Jørgensen T; Borch-Johnsen K; Jeppesen J

2012-04-01

328

Plasminogen activator inhibitor-1 mitigates brain injury in a rat model of infection-sensitized neonatal hypoxia-ischemia.  

UK PubMed Central (United Kingdom)

Intrauterine infection exacerbates neonatal hypoxic-ischemic (HI) brain injury and impairs the development of cerebral cortex. Here we used low-dose lipopolysaccharide (LPS) pre-exposure followed by unilateral cerebral HI insult in 7-day-old rats to study the pathogenic mechanisms. We found that LPS pre-exposure blocked the HI-induced proteolytic activity of tissue-type plasminogen activator (tPA), but significantly enhanced NF-?B signaling, microglia activation, and the production of pro-inflammatory cytokines in newborn brains. Remarkably, these pathogenic responses were all blocked by intracerebroventricular injection of a stable-mutant form of plasminogen activator protein-1 called CPAI. Similarly, LPS pre-exposure amplified, while CPAI therapy mitigated HI-induced blood-brain-barrier damage and the brain tissue loss with a therapeutic window at 4 h after the LPS/HI insult. The CPAI also blocks microglia activation following a brain injection of LPS, which requires the contribution by tPA, but not the urinary-type plasminogen activator (uPA), as shown by experiments in tPA-null and uPA-null mice. These results implicate the nonproteolytic tPA activity in LPS/HI-induced brain damage and microglia activation. Finally, the CPAI treatment protects near-normal motor and white matter development despite neonatal LPS/HI insult. Together, because CPAI blocks both proteolytic and nonproteolytic tPA neurotoxicity, it is a promising therapeutics of neonatal HI injury either with or without infection.

Yang D; Sun YY; Nemkul N; Baumann JM; Shereen A; Dunn RS; Wills-Karp M; Lawrence DA; Lindquist DM; Kuan CY

2013-05-01

329

Inhibition of one-chain and two-chain forms of human tissue-type plasminogen activator by the fast-acting inhibitor of plasminogen activator in vitro and in vivo.  

Science.gov (United States)

The inhibition of one-chain and two-chain molecular forms of human tissue-type plasminogen activator (t-PA) by the fast-acting inhibitor of plasminogen activator (PA-inhibitor) present in plasma was studied in vitro and in vivo in rabbits. In vitro, both one-chain and two-chain forms of t-PA were neutralized very rapidly in rabbit plasma with high levels of PA-inhibitor. The rate constant of the interaction between two-chain t-PA and PA-inhibitor was estimated to be 3.10(7) L/mol/sec. The presence of CNBr-digested fibrinogen, which mimics the effect of fibrin on the activation of plasminogen by t-PA, did not influence the rate constant. Moreover, PA-inhibitor-rich plasma inhibited in a very similar way in vitro thrombolysis by one-chain or two-chain t-PA incorporated into the clot. Injection of one-chain or two-chain t-PA into rabbits with increased levels of PA-inhibitor, induced by endotoxin, resulted in very rapid inhibition of t-PA activity. Within 30 seconds after injection, no residual free t-PA could be demonstrated. Gel filtration analysis showed that the disappearance of t-PA activity was associated with the generation of t-PA-PA-inhibitor complex with an apparent Mr of 100,000. This enzyme-inhibitor complex, like free t-PA, was cleared from the circulation with a half-life of approximately 2 minutes, mainly via the liver. It is concluded that PA-inhibitor neutralizes one-chain and two-chain molecular forms of t-PA in plasma at very similar rates, both in vitro and in vivo.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3086473

Colucci, M; Paramo, J A; Collen, D

1986-07-01

330

Inhibition of one-chain and two-chain forms of human tissue-type plasminogen activator by the fast-acting inhibitor of plasminogen activator in vitro and in vivo.  

UK PubMed Central (United Kingdom)

The inhibition of one-chain and two-chain molecular forms of human tissue-type plasminogen activator (t-PA) by the fast-acting inhibitor of plasminogen activator (PA-inhibitor) present in plasma was studied in vitro and in vivo in rabbits. In vitro, both one-chain and two-chain forms of t-PA were neutralized very rapidly in rabbit plasma with high levels of PA-inhibitor. The rate constant of the interaction between two-chain t-PA and PA-inhibitor was estimated to be 3.10(7) L/mol/sec. The presence of CNBr-digested fibrinogen, which mimics the effect of fibrin on the activation of plasminogen by t-PA, did not influence the rate constant. Moreover, PA-inhibitor-rich plasma inhibited in a very similar way in vitro thrombolysis by one-chain or two-chain t-PA incorporated into the clot. Injection of one-chain or two-chain t-PA into rabbits with increased levels of PA-inhibitor, induced by endotoxin, resulted in very rapid inhibition of t-PA activity. Within 30 seconds after injection, no residual free t-PA could be demonstrated. Gel filtration analysis showed that the disappearance of t-PA activity was associated with the generation of t-PA-PA-inhibitor complex with an apparent Mr of 100,000. This enzyme-inhibitor complex, like free t-PA, was cleared from the circulation with a half-life of approximately 2 minutes, mainly via the liver. It is concluded that PA-inhibitor neutralizes one-chain and two-chain molecular forms of t-PA in plasma at very similar rates, both in vitro and in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Colucci M; Paramo JA; Collen D

1986-07-01

331

Transcriptional Upregulation of Plasminogen Activator Inhibitor-1 in Rat Primary Astrocytes by a Proteasomal Inhibitor MG132.  

UK PubMed Central (United Kingdom)

Plasminogen activator inhibitor-1 (PAI-1) is a member of serine protease inhibitor family, which regulates the activity of tissue plasminogen activator (tPA). In CNS, tPA/PAI-1 activity is involved in the regulation of a variety of cellular processes such as neuronal development, synaptic plasticity and cell survival. To gain a more insights into the regulatory mechanism modulating tPA/PAI-1 activity in brain, we investigated the effects of proteasome inhibitors on tPA/PAI-1 expression and activity in rat primary astrocytes, the major cell type expressing both tPA and PAI-1. We found that submicromolar concentration of MG132, a cell permeable peptide-aldehyde inhibitor of ubiquitin proteasome pathway selectively upregulates PAI-1 expression. Upregulation of PAI-1 mRNA as well as increased PAI-1 promoter reporter activity suggested that MG132 transcriptionally increased PAI-1 expression. The induction of PAI-1 downregulated tPA activity in rat primary astrocytes. Another proteasome inhibitor lactacystin similarly increased the expression of PAI-1 in rat primary astrocytes. MG132 activated MAPK pathways as well as PI3K/Akt pathways. Inhibitors of these signaling pathways reduced MG132-mediated upregulation of PAI-1 in varying degrees and most prominent effects were observed with SB203580, a p38 MAPK pathway inhibitor. The regulation of tPA/PAI-1 activity by proteasome inhibitor in rat primary astrocytes may underlie the observed CNS effects of MG132 such as neuroprotection.

Cho KS; Kwon KJ; Jeon SJ; Joo SH; Kim KC; Cheong JH; Bahn GH; Kim HY; Han SH; Shin CY; Yang SI

2013-03-01

332

Recombinant ADAMTS13 reduces tissue plasminogen activator-induced hemorrhage after stroke in mice.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Tissue plasminogen activator (tPA) is approved for treatment of acute ischemic stroke, but it increases the risk of cerebral hemorrhage. Accumulating evidence suggests that von Willebrand factor (VWF) plays a pivotal role in thrombus formation and microcirculatory disturbances after ischemic stroke. By cleaving VWF, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) protects mice from stroke. Therefore, we hypothesized that recombinant ADAMTS13 (rADAMTS13) could increase the safety of tPA thrombolysis in stroke. METHODS: We examined blood-brain barrier (BBB) permeability after intraventricular injection of tPA, VWF, and rADAMTS13 in nonischemic mice. We investigated the role of rADAMTS13 on reducing tPA-induced BBB dysfunction and cerebral hemorrhage in a mouse stroke model. RESULTS: Intraventricular injection of tPA or VWF under nonischemic conditions resulted in a significant increase in BBB permeability. In contrast, rADAMTS13 blocked both tPA- and VWF-induced BBB opening. BBB disruption following stroke was exacerbated by intravenous administration of tPA, but this was attenuated by injection of rADAMTS13. Correspondingly, tPA-associated hemorrhage after stroke was significantly reduced by rADAMTS13. The antihemorrhagic effect of rADAMTS13 was reversed by injection of recombinant VWF. We also showed that rADAMTS13 inhibited tPA-mediated upregulation of vascular endothelial growth factor (VEGF) in vascular endothelium after stroke. The upregulation of VEGF was suppressed by either an Akt inhibitor wortmannin or a Rho kinase inhibitor fasudil. Furthermore, rADAMTS13 downregulated tPA-induced phosphorylation of Akt and activation of RhoA. INTERPRETATION: These findings demonstrate that the VWF-cleaving protease rADAMTS13 reduced tPA-induced hemorrhage by regulating BBB integrity, and suggest that this effect may occur through the Akt/RhoA-mediated VEGF pathways.

Wang L; Fan W; Cai P; Fan M; Zhu X; Dai Y; Sun C; Cheng Y; Zheng P; Zhao BQ

2013-02-01

333

Lysis of intracerebral hematoma with stereotactically implanted tissue plasminogen activator polymers in a rabbit model.  

UK PubMed Central (United Kingdom)

OBJECT: Currently no adequate surgical treatment exists for spontaneous intracerebral hemorrhage (ICH). Implantable polymers can be used effectively to deliver therapeutic agents to the local site of the pathological process, thus reducing adverse systemic effects. The authors report the use of stereotactically implanted polymers loaded with tissue plasminogen activator (tPA) to induce lysis of ICH in a rabbit model. METHODS: Ethylene vinyl acetate (EVAc) polymers were loaded with bovine serum albumin (BSA) only or with BSA plus tPA. In vitro pharmacokinetic (three polymers) and thrombolysis (12 polymers) studies were performed. For the in vivo study, 12 rabbits were fixed in a stereotactic frame, and 0.2 ml of clotted autologous blood was injected into the right frontal lobe parenchyma. After 20 minutes, control BSA polymers were stereotactically implanted at the hemorrhage site in six rabbits, and experimental BSA plus tPA polymers were implanted in six rabbits. Animals were killed at 3 days, and blood clot volume was assessed. The pharmacokinetic study showed release of 146 ng of tPA over 3 days. The tPA activity correlated with in vitro thrombolysis. In the in vivo study, the six animals treated with tPA polymers had a mean (+/- standard error of the mean [SEM]) thrombus volume of 1.43 +/- 0.29 mm3 at 3 days, whereas the six animals treated with blank (BSA-only) polymers had a mean (+/- SEM) thrombus volume of 19.99 +/- 3.74 mm3 (p < 0.001). CONCLUSIONS: Ethylene vinyl acetate polymers release tPA over the course of 3 days. Stereotactic implantation of tPA-loaded EVAc polymers significantly reduced ICH volume. Polymers loaded with tPA may be useful clinically for lysis of ICH without the side effects of systemic administration of tPA.

Thai QA; Pradilla G; Legnani FG; Kretzer RM; Hsu W; Tamargo RJ

2006-09-01

334

Tissue-type plasminogen activator is an extracellular mediator of Purkinje cell damage and altered gait.  

UK PubMed Central (United Kingdom)

Purkinje neurons are a sensitive and specialized cell type important for fine motor movement and coordination. Purkinje cell damage manifests as motor incoordination and ataxia - a prominent feature of many human disorders including spinocerebellar ataxia and Huntington's disease. A correlation between Purkinje degeneration and excess cerebellar levels of tissue-type plasminogen activator (tPA) has been observed in multiple genetically-distinct models of ataxia. Here we show that Purkinje loss in a mouse model of Huntington's disease also correlates with a 200% increase in cerebellar tPA activity. That elevated tPA levels arise in a variety of ataxia models suggests that tPA is a common mediator of Purkinje damage. To address the specific contribution of tPA to cerebellar dysfunction we studied the T4 mice line that overexpresses murine tPA in postnatal neurons through the Thy1.2 gene promoter, which directs preferential expression to Purkinje cells within the cerebellum. Here we show that T4 mice develop signs of cerebellar damage within 10 weeks of birth including atrophy of Purkinje cell soma and dendrites, astrogliosis, reduced molecular layer volume and altered gait. In contrast, T4 mice displayed no evidence of microgliosis, nor any changes in interneuron density or alteration in the cerebellar granular neuron layer. Thus, excess tPA levels may be sufficient to cause targeted Purkinje cell degeneration and ataxia. We propose that elevated cerebellar tPA levels exert a common pathway of Purkinje cell damage. Therapeutically lowering cerebellar tPA levels may represent a novel means of preserving Purkinje cell integrity and motor coordination across a wide range of neurodegenerative diseases.

Cops EJ; Sashindranath M; Daglas M; Short KM; da Fonseca Pereira C; Pang TY; Lijnen RH; Smyth IM; Hannan AJ; Samson AL; Medcalf RL

2013-08-01

335

Tissue-type plasminogen activator is an extracellular mediator of Purkinje cell damage and altered gait.  

Science.gov (United States)

Purkinje neurons are a sensitive and specialised cell type important for fine motor movement and coordination. Purkinje cell damage manifests as motor incoordination and ataxia - a prominent feature of many human disorders including spinocerebellar ataxia and Huntington's disease. A correlation between Purkinje degeneration and excess cerebellar levels of tissue-type plasminogen activator (tPA) has been observed in multiple genetically-distinct models of ataxia. Here we show that Purkinje loss in a mouse model of Huntington's disease also correlates with a 200% increase in cerebellar tPA activity. That elevated tPA levels arise in a variety of ataxia models suggests that tPA is a common mediator of Purkinje damage. To address the specific contribution of tPA to cerebellar dysfunction we studied the T4 mice line that overexpresses murine tPA in postnatal neurons through the Thy1.2 gene promoter, which directs preferential expression to Purkinje cells within the cerebellum. Here we show that T4 mice develop signs of cerebellar damage within 10weeks of birth including atrophy of Purkinje cell soma and dendrites, astrogliosis, reduced molecular layer volume and altered gait. In contrast, T4 mice displayed no evidence of microgliosis, nor any changes in interneuron density, nor alteration in the cerebellar granular neuron layer. Thus, excess tPA levels may be sufficient to cause targeted Purkinje cell degeneration and ataxia. We propose that elevated cerebellar tPA levels exert a common pathway of Purkinje cell damage. Therapeutically lowering cerebellar tPA levels may represent a novel means of preserving Purkinje cell integrity and motor coordination across a wide range of neurodegenerative diseases. PMID:23939410

Cops, Elisa J; Sashindranath, Maithili; Daglas, Maria; Short, Kieran M; da Fonseca Pereira, Candida; Pang, Terence Y; Lijnen, Roger H; Smyth, Ian M; Hannan, Anthony J; Samson, Andre L; Medcalf, Robert L

2013-08-09

336

Tissue plasminogen activator enhances mobilization of endothelial progenitor cells and angiogenesis in murine limb ischemia.  

UK PubMed Central (United Kingdom)

BACKGROUND: It has been reported that plasmin induces migration of endothelial cells. We hypothesized that tissue plasminogen activator (tPA) enhanced endothelial progenitor cell (EPC) mobilization from bone marrow (BM) into the circulation and angiogenesis in murine critical limb ischemia (CLI). METHODS: Forty male B6 mice were randomly divided into group 1 (control), group 2 [control+recombinant tPA (intra-venous 4mg/kg)], group 3 (CLI) and group 4 (CLI+tPA). RESULTS: The results demonstrated higher MMP-9 activity in BM and circulatory SDF-1? level in groups 2 and 3 than in group 1, and highest in group 4 (all p<0.01) at 18h after CLI. Compared with circulation, SDF-1? level in BM showed an opposite trend (all p<0.03). The circulating EPC (C-kit/CD31, Sca-1/KDR, CXCR4/CD34) levels at 18h after CLI were higher in group 2 than in groups 1 and 3, and highest in group 4 (all p<0.03). EPC (C-kit/CD31, Sca-1/KDR) levels in BM were lower in group 1 than in groups 2 to 4 (all p<0.03), whereas number of CXCR4/CD34-positive EPCs in BM did not differ among the four groups at 18h after CLI. Protein expressions of SDF-1?, CXCR4, eNOS, and VEGF, numbers of CD31+, CXCR4+, SDF-1?+, and vWF+ cells through immunofluorescent staining, numbers of small vessels (<15?m) and blood flow measured by Laser Doppler in an ischemic area were significantly higher in group 4 than in group 3 (all p<0.005) at day 14 after CLI. CONCLUSION: tPA treatment enhanced number of circulating EPCs, angiogenesis, and blood flow to ischemic tissue in a murine model of limb ischemia.

Yip HK; Sun CK; Tsai TH; Sheu JJ; Kao YH; Lin YC; Shiue YL; Chen YL; Chai HT; Chua S; Ko SF; Leu S

2013-09-01

337

Antibody-mediated targeting of the urokinase-type plasminogen activator proteolytic function neutralizes fibrinolysis in vivo  

DEFF Research Database (Denmark)

Urokinase-type plasminogen activator (uPA) plays a central role in tissue remodeling processes. Most of our understanding of the role of uPA in vivo is derived from studies using gene-targeted uPA-deficient mice. To enable in vivo studies on the specific interference with uPA functionality in mouse models, we have now developed murine monoclonal antibodies (mAbs) directed against murine uPA by immunization of uPA-deficient mice with the recombinant protein. Guided by enzyme-linked immunosorbent assay, Western blotting, surface plasmon resonance, and enzyme kinetic analyses, we have selected two highly potent and inhibitory anti-uPA mAbs (mU1 and mU3). Both mAbs recognize epitopes located on the B-chain of uPA that encompasses the catalytic site. In enzyme activity assays in vitro, mU1 blocked uPA-catalyzed plasminogen activation as well as plasmin-mediated pro-uPA activation, whereas mU3 only was directed against the first of these reactions. We additionally provide evidence that mU1, but not mU3, successfully targets uPA-dependent processes in vivo. Hence, systemic administration of mU1 (i) rescued mice treated with a uPA-activable anthrax protoxin and (ii) impaired uPA-mediated hepatic fibrinolysis in tissue-type plasminogen activator (tPA)-deficient mice, resulting in a phenotype mimicking that of uPA;tPA double deficient mice. Importantly, this is the first report demonstrating specific antagonist-directed targeting of mouse uPA at the enzyme activity level in a normal physiological process in vivo.

Lund, Ida K; Jögi, Annika

2008-01-01

338

Studies on a complex mechanism for the activation of plasminogen by kaolin and by chloroform: the participation of Hageman factor and additional cofactors.  

Science.gov (United States)

As demonstrated by others, fibrinolytic activity was generated in diluted, acidified normal plasma exposed to kaolin, a process requiring Hageman factor (Factor XII). Generation was impaired by adsorbing plasma with glass or similar agents under conditions which did not deplete its content of Hageman factor or plasminogen. The defect could be repaired by addition of a noneuglobulin fraction of plasma or an agent or agents eluted from diatomaceous earth which had been exposed to normal plasma. The restorative agent, tentatively called Hageman factor-cofactor, was partially purified by chromatography and had an apparent molecular weight of approximately 165,000. It could be distinguished from plasma thromboplastin antecedent (Factor XI) and plasma kallikrein, other substrates of Hageman factor, and from the streptokinase-activated pro-activator of plasminogen. Evidence is presented that an additional component may be needed for the generation of fibrinolytic activity in mixtures containing Hageman factor, HF-cofactor, and plasminogen.The long-recognized generation of plasmin activity in chloroform-treated euglobulin fractions of plasma was found to be dependent upon the presence of Hageman factor. Whether chloroform activation of plasminogen requires Hageman factor-cofactor was not determined, but glass-adsorbed plasma, containing Hageman factor and plasminogen, did not generate appreciable fibrinolytic or caseinolytic activity. These studies emphasize the complex nature of the mechanisms which lead to the generation of plasmin in human plasma. PMID:4241814

Ogston, D; Ogston, C M; Ratnoff, O D; Forbes, C D

1969-10-01

339

Binding of plasminogen to extracellular matrix.  

UK PubMed Central (United Kingdom)

We have previously demonstrated that plasminogen immobilized on various surfaces forms a substrate for efficient conversion to plasmin by tissue plasminogen activator (t-PA) (Silverstein, R. L., Nachman, R. L., Leung, L. L. K., and Harpel, R. C. (1985) J. Biol. Chem. 260, 10346-10352). We now report the binding of human plasminogen to the extracellular matrix synthesized in vitro by cultured endothelial cell monolayers. The binding was specific, saturable at plasma plasminogen concentrations, reversible, and lysine-binding site-dependent. Functional studies demonstrated that matrix immobilized plasminogen was a much better substrate for t-PA than was fluid phase plasminogen as shown by a 100-fold decrease in Km. Activation of plasminogen by t-PA and urokinase on the matrix was equally efficient. The plasmin generated on the matrix, in marked contrast to fluid phase, was protected from its fast-acting inhibitor, alpha 2-plasmin inhibitor. Matrix-associated plasmin converted bound Glu- into Lys-plasminogen, which in turn is more rapidly activated to plasmin by t-PA. The extracellular matrix not only binds and localizes plasminogen but also improves plasminogen activation kinetics and prolongs plasmin activity in the subendothelial microenvironment.

Knudsen BS; Silverstein RL; Leung LL; Harpel PC; Nachman RL

1986-08-01

340

Plasminogen Acquisition and Activation at the Surface of Leptospira Species Lead to Fibronectin Degradation ?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pathogenic Leptospira species are the etiological agents of leptospirosis, a widespread disease of human and veterinary concern. In this study, we report that Leptospira species are capable of binding plasminogen (PLG) in vitro. The binding to the leptospiral surface was demonstrated by indirect imm...

Vieira, Monica L.; Vasconcellos, Silvio A.; Gonçales, Amane P.; de Morais, Zenaide M.; Nascimento, Ana L. T. O.

 
 
 
 
341

Soluble Urokinase Plasminogen Activator Receptor for Risk Prediction in Patients Admitted with Acute Chest Pain.  

UK PubMed Central (United Kingdom)

BACKGROUND: Plasma concentrations of soluble urokinase plasminogen activator receptor (suPAR) predict mortality in several clinical settings, but the long-term prognostic importance of suPAR in chest pain patients admitted on suspicion of non-ST-segment elevation acute coronary syndrome (NSTEACS) is uncertain.METHODS: suPAR concentrations were measured on admission in 449 consecutive chest pain patients in a single center between January 3, 2005, and February 14, 2006. Patients were followed for all-cause mortality from discharge until July 28, 2011.RESULTS: The diagnoses at discharge comprised high-risk NSTEACS [non-ST elevation myocardial infarction or unstable angina with electrocardiogram (ECG) abnormalities] in 77 patients (17.2%) and low-risk NSTEACS without evidence of myocardial ischemia in 257 (57.2%) of patients. Another 115 (25.6%) of patients received other diagnoses. During a median follow-up of 5.7 years (range, 0.01-6.6 years) there were 162 (36.1%) deaths. suPAR was predictive of mortality independent of age, sex, smoking, final diagnosis for the hospitalization, comorbidities (diabetes, hypertension, previous myocardial infarction, and heart failure), and variables measured on the day of admission (renal function, inflammatory markers, and markers of myocardial ischemia) with a hazard ratio (95% CI) of 1.93 (1.48-2.51) per SD increase in log-transformed suPAR, P < 0.0001. The use of suPAR improved the predictive accuracy of abnormal ECG findings and increased troponin concentrations regarding all-cause mortality (c statistics, 0.751-0.805; P < 0.0001).CONCLUSIONS: suPAR is a strong predictor of adverse long-term outcomes and improves risk stratification beyond traditional risk variables in chest pain patients admitted with suspected NSTEACS.

Lyngbæk S; Andersson C; Marott JL; Møller DV; Christiansen M; Iversen KK; Clemmensen P; Eugen-Olsen J; Hansen PR; Jeppesen JL

2013-07-01

342

Tissue-type plasminogen activator as marker of functional steroid receptors in human breast cancer.  

UK PubMed Central (United Kingdom)

The relationship between tissue-type plasminogen activator (t-PA) antigen content and receptor status was investigated in 200 human breast cancer cytosols to evaluate the efficacy of t-PA as a marker of functional steroid receptors. t-PA level was measured by an enzyme-linked immunoassay (ELISA) and estrogen (ER) and progesterone (PgR) receptors were assayed by the DCC method. A highly significant correlation was found between t-PA levels and receptor status. The mean +/- SE enzyme content was 13.5 +/- 2.9 in ER+ tumors and 1.8 +/- 0.3 ng/mg protein in ER- tumors; the enzyme content in PgR+ tumors was 14.2 +/- 3.3 and 3.4 +/- 1.4 ng/mg protein in PgR- tumors. When tumors were divided into four subgroups according to receptor content (ER+PgR+, ER+PgR-, ER-PgR+, and ER-PgR-), t-PA concentration was able to differentiate these groups. Also, t-PA level was compared to several clinical variables; it was not correlated with menopausal status or lymph node involvement. However, t-PA content varied according to tumor size. Our data shows that t-PA content in tumor cytosols is statistically related to receptor status and that determination of t-PA levels in breast cancer might furnish additional information as to the functional state of the receptors which may be necessary for planning hormone therapy.

Rella C; Coviello M; Quaranta M; Paradiso A

1993-01-01

343

Role of plasminogen activator inhibitor-1 in urokinase's paradoxical in vivo tumor suppressing or promoting effects.  

Science.gov (United States)

Tumor proteases and inhibitors have been associated with paradoxical effects on tumor progression in preclinical and clinical settings. We previously reported that urokinase (uPA) overexpression delays tumor progression in mammary cancer. This study aimed to determine the role of plasminogen activator inhibitor-1 (PAI-1) on uPA's paradoxical in vivo effects. Using syngeneic murine models, we found that stable uPA overexpression promoted in vivo growth of colon tumors (MC-38) naturally expressing high PAI-1, whereas growth inhibition was observed in renal tumors (RENCA) expressing lower PAI-1 levels. In murine mammary carcinoma (4T1), uPA overexpression shifted the uPA/PAI-1 balance in favor of the protease, resulting in significantly reduced tumor growth and metastases in vivo. Conversely, increased tumor progression was observed in stable PAI-1 overexpressing 4T1 tumors as compared with uPA-overexpressing and control tumors. These effects were associated with downregulation of metastases promoting genes in uPA-overexpressing tumors, such as metalloproteinases, CXCL-1, c-Fos, integrin ?-5, VEGF-A, PDGF-?, and IL-1?. In PAI-1-overexpressing tumors, many of the above genes were upregulated. PAI-1 overexpressing tumors had increased total and new tumor microvessels, and increased tumor cell proliferation, whereas the opposite effects were found in uPA-overexpressing tumors. Finally, PAI-1 downregulation led to significant inhibition of 4T1 tumor growth and metastases in vivo. In conclusion, uPA's dual effects on tumor progression occur in the context of its interactions with endogenous PAI-1 expression. Our studies uncover novel mechanisms of in vivo tumor control by modulation of the balance between tumor proteases and inhibitors, which may be exploited therapeutically. PMID:22912336

Jing, Yuqi; Kovacs, Krisztina; Kurisetty, Vittal; Jiang, Zhijie; Tsinoremas, Nick; Merchan, Jaime R

2012-08-21

344

Recombinant human erythropoietin reduces plasminogen activator inhibitor and ameliorates pro-inflammatory responses following trauma  

Directory of Open Access Journals (Sweden)

Full Text Available "n  "n Background and the purpose of the study: Besides its hematopoietic effects, erythropoietin (EPO) by mobilization of iron and modulation of some inflammatory cytokines has antioxidant and anti-inflammatory properties. The purpose of this study was to evaluate these effects of erythropoietin and its impact on organ function in traumatized patients. "n Methods: Twenty-six ICU-admitted traumatized patients within 24 hrs after trauma were randomly assigned to the EPO (received EPO, 300 units/Kg/day) and Control (not received EPO) groups. The inflammatory biomarkers including Tumor Necrosis Factor alpha (TNF-?), Interleukin 1 (IL-1), Plasminogen Activator Inhibitor 1 (PAI-1) and Nitrotyrosine were recorded at the admission, 3, 6 and 9 days thereafter. Acute Physiology and Chronic Health Evaluation (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores were also recorded. "n Results: Among 12 patients (EPO group) TNF-? level at the day of 9 (P=0.046), and within EPO group at the days of 3 (P=0.026 ameliorate), 6 (P=0.016), and 9 (P=0.052) were significantly lowered. Level of IL-1 and PAI-1 decreased significantly at days of 3, 6 and 9 post intervention. Also there were significant differences between two groups in the SOFA score during three measured time intervals (the first, third and seventh days). "n Conclusion: From the results of this study it seems that injection of erythrocyte stimulating agent is well tolerated and inhibits the inflammatory response and oxidative stress following trauma.

M Shiehmorteza; A Ahmadi; M Abdollahi; M Nayebpour; M Mohammadi; H Hamishehkar; A Najafi; M Pazoki; M Mojtahedzadeh

2011-01-01

345

Steroids and plasminogen activator concentrations in follicular fluid of gilts at first and third estrus.  

UK PubMed Central (United Kingdom)

An experiment was conducted to determine whether morphological and functional characteristics of follicles differed at a similar stage of pubertal (first) and third estrus in the same gilts. Nine prepubertal gilts were checked three times daily for estrus and laparotomized 6 h after detected first and third estrus. Samples of vena cava and ovarian venous blood were collected, follicle numbers and diameters were recorded, and follicular fluid (FF) was aspirated from all follicles 8 to 12 mm in diameter. Sera and(or) FF were analyzed for progesterone (P4), estradiol-17 beta (E2), testosterone (T), androstenedione (A4), 5 alpha-dihydrotestosterone (DHT), plasminogen activator (PA), and plasmin (PLM). Overall mean number of follicles > or = 8 mm in diameter did not differ between gilts at first and third estrus (P > .05) but gilts at first estrus had more follicles 4 to 8 (P < .05) and 8.1 to 10 mm in diameter (P < .01) and fewer 10.1 to 12 mm in diameter (P < .07) than at third estrus. Mean FF concentrations of E2, T, and A4 at third estrus were significantly greater than at first estrus, whereas FF concentrations of P4, DHT, PA, and PLM were similar at first and third estrus (P > .05). Mean concentrations of E2 in systemic and ovarian venous sera were also greater in gilts at third than at first estrus (both P < .05). Systemic concentrations of P4 in gilts at first and third estrus did not differ (P > .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Smith GD; Menino AR Jr; Rowe KE; Stormshak F

1992-12-01

346

Comparison of pneumatic displacement for submacular hemorrhages with gas alone and gas plus tissue plasminogen activator.  

UK PubMed Central (United Kingdom)

PURPOSE: To retrospectively evaluate efficacy, safety, and visual outcomes of pneumatic displacement for submacular hemorrhages (SMHs) with or without tissue plasminogen activator (tPA). METHODS: Sixty-eight eyes with fresh SMHs underwent pneumatic displacement. Thirty eyes received intravitreal injection of pure C3F8 gas alone and 38 eyes received gas with tPA (25 ?g). The visual analog scale was used to evaluate displacement. The main outcome measures were the visual analog scale score and best-corrected visual acuity 1 month after treatment. The efficacy and safety of tPA were evaluated. RESULTS: The visual analog scale score was 4.9 ± 2.5 in the gas group and 5.9 ± 2.9 in the gas plus tPA group. Sixteen eyes (53.3%) in the gas group and 15 eyes (39.5%) in the gas plus tPA group had best-corrected visual acuity improvements. In the gas group, complications included retinal detachment (n = 1, 3.3%), vitreous opacity (n = 7, 23.3%), and rebleeding (n = 1, 3.3%). In the gas plus tPA group, vitreous opacity (n = 6, 15.8%) was the only complication. Overall, both groups had similar displacement of SMH, visual improvement, and complication rates at 1 month. CONCLUSION: Intravitreal injection of pure C3F8 gas displaced SMHs and improved best-corrected visual acuity in eyes with SMHs. No adjuvant effect or adverse reactions of tPA were found.

Fujikawa M; Sawada O; Miyake T; Kakinoki M; Sawada T; Kawamura H; Sakaguchi H; Gomi F; Ohji M

2013-10-01

347

Pharmacokinetics and thrombolytic effects of the recombinant tissue-type plasminogen activator in horses  

Science.gov (United States)

Background To test the efficacy of the recombinant tissue-type plasminogen activator (rt-PA) alteplase in horses, the thrombolytic effect was tested in in vitro generated equine thrombi. The extent of lysis was determined by measuring the decrease in thrombi weight over a period of 4 hours. In vivo pharmacokinetics of alteplase were determined in 6 healthy horses. A single dose (1 mg/kg) was applied via intravenous infusion over a period of 30 minutes Coagulation-related variables, blood count and clinical parameters were taken before the treatment and until 48 h after treatment. In addition, plasma rt-PA concentration was measured until 300 min after commencing the infusion. Results In vitro, a dose dependent decrease of thrombus weight ranging from a 56 (± 6.5) % decrease for 0.5 ?g/ml to 92 (± 2.1) % decrease for 5 ?g/ml rt-PA was noted. The D-dimer concentration in the lysis medium correspondingly increased from 0.10 up to 10.8 mg/l. In vivo, none of the horses showed an adverse reaction to the alteplase infusion. In some horses blood parameters were slightly altered. The 1 mg/kg dose yielded the following pharmacokinetic parameters: Cmax = 1.25?±?0.27 ?g/ml; CL = 21.46?±?5.67 ml/min/kg; dominant half life (t1/2?) = 6.81?±?1.48 minutes; median elimination half life (t1/2?) = 171 min (range: 85–1061); AUC = 50.33?±?17.62 ?g?·?min /ml. Conclusion These findings indicate that a single dose of 1 mg/kg alteplase results in rt-PA plasma concentrations comparable to those in humans and might be sufficient for a thrombolytic therapy in horses. Further studies must be performed to determine the alteplase effectiveness in horses with jugular vein thrombosis.

2013-01-01

348

Tissue plasminogen activator in trabecular meshwork attenuates steroid induced outflow resistance in mice.  

UK PubMed Central (United Kingdom)

Tissue plasminogen activator, a serine protease encoded by the PLAT gene is present in the trabecular meshwork (TM) and other ocular tissues and has been reported to be downregulated by treatment with steroids in vitro. Steroids are known to cause changes in outflow facility of aqueous humor in many species. In the present study, we tested whether overexpression of PLAT can prevent and/or reverse the outflow facility of mouse eyes treated with steroids. Animals received bilateral injection with 20 µl of triamcinolone acetonide (TA) (40 mg/ml) suspension subconjunctivally to induce outflow facility changes. Some animals received unilateral intracameral injection with 2 µl of adenoviral suspension [3-4 x 10(12) virus genomes per milliliter (vg/ml)] carrying sheep PLAT cDNA (AdPLAT) either concurrently with TA injection or one week after TA injection, whereas others received bilateral intracameral injection with 2 µl of adenoviral suspension (9 x 10(12) vg/ml) carrying no transgene (AdNull) concurrently with TA injection. Animals were sacrificed one week after AdPLAT or AdNull treatment. Endogenous mRNA expression levels of mouse PAI-1 and MMP-2, -9 and -13 were also measured using qRT-PCR. Outflow facility one week after AdPLAT administration was increased by 60% and 63% respectively for animals that had not or had been pretreated with steroids. Overexpression of PLAT significantly upregulated expression of PAI-1, MMP-2, -9 and -13 compared to the levels found in TA only treated eyes. These findings suggest that overexpression of PLAT in TM of mouse eyes can both prevent and reverse the decrease in outflow facility caused by steroid treatment and is associated with upregulation of MMPs.

Kumar S; Shah S; Tang HM; Smith M; Borrás T; Danias J

2013-01-01

349

Tissue plasminogen activator in trabecular meshwork attenuates steroid induced outflow resistance in mice.  

Science.gov (United States)

Tissue plasminogen activator, a serine protease encoded by the PLAT gene is present in the trabecular meshwork (TM) and other ocular tissues and has been reported to be downregulated by treatment with steroids in vitro. Steroids are known to cause changes in outflow facility of aqueous humor in many species. In the present study, we tested whether overexpression of PLAT can prevent and/or reverse the outflow facility of mouse eyes treated with steroids. Animals received bilateral injection with 20 µl of triamcinolone acetonide (TA) (40 mg/ml) suspension subconjunctivally to induce outflow facility changes. Some animals received unilateral intracameral injection with 2 µl of adenoviral suspension [3-4 x 10(12) virus genomes per milliliter (vg/ml)] carrying sheep PLAT cDNA (AdPLAT) either concurrently with TA injection or one week after TA injection, whereas others received bilateral intracameral injection with 2 µl of adenoviral suspension (9 x 10(12) vg/ml) carrying no transgene (AdNull) concurrently with TA injection. Animals were sacrificed one week after AdPLAT or AdNull treatment. Endogenous mRNA expression levels of mouse PAI-1 and MMP-2, -9 and -13 were also measured using qRT-PCR. Outflow facility one week after AdPLAT administration was increased by 60% and 63% respectively for animals that had not or had been pretreated with steroids. Overexpression of PLAT significantly upregulated expression of PAI-1, MMP-2, -9 and -13 compared to the levels found in TA only treated eyes. These findings suggest that overexpression of PLAT in TM of mouse eyes can both prevent and reverse the decrease in outflow facility caused by steroid treatment and is associated with upregulation of MMPs. PMID:23977299

Kumar, Sandeep; Shah, Shaily; Tang, Hai Michael; Smith, Matthew; Borrás, Teresa; Danias, John

2013-08-19

350

[Expressions and clinical significance of urokinase-type plasminogen activator and its receptor in vulvar tissues].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To explore the expressions of urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in vulvar tissues and elucidate the patterns. METHODS: Thirty cases of vulvar neoplasms, 30 vulvar intraepithelial neoplasia (VIN) and 30 cases of normal epithelial tissue were harvested. And the expressions of uPA and uPAR in paraffin-embedded tissues were detected by immunohistochemistry. And the differential expressions of various vulvar tissues were observed. And the differences were compared in clinical stage and lymph node metastasis. RESULTS: (1) The expressions of uPA and uPAR in normal tissues (0.422 ± 0.022, 0.431 ± 0.027), vulvar intraepithelial neoplasia (VIN) (0.462 ± 0.018, 0.467 ± 0.015) and vulvar neoplasms (0.508 ± 0.020, 0.510 ± 0.020) were significantly different (P < 0.01). (2) The expressions of uPA and uPAR in vulvar tissue significantly increased with a rising stage-level (P < 0.05). (3) Compared with those without lymph node metastasis, the patients with lymph node metastasis had significantly higher expressions of uPA and uPAR in vulvar tissue (P < 0.05). CONCLUSION: Thus uPA and uPAR play an important role in the development process of vulvar neoplasms with an elevated expression in normal vulvar tissue, VIN and vulvar neoplasms. The invasiveness and prognosis of vulvar neoplasms may be evaluated through detecting the tissue expressions of uPA and uPAR.

Tian Y; Zhang XJ; Li GF; Wang W

2011-09-01

351

Functional plasminogen activator inhibitor-1 gene variants and breast cancer survival.  

UK PubMed Central (United Kingdom)

PURPOSE: Plasminogen activator inhibitor-1 (PAI-1) plays an important role in cancer invasion and metastasis. A common polymorphism (4G/5G) in the promoter region of the PAI-1 gene has been reported to influence transcription and plasma levels of PAI-1. We evaluated the association between PAI-1 4G/5G polymorphism and breast cancer survival in a population-based cohort of breast cancer patients. EXPERIMENTAL DESIGN: Included in this analysis were 1,083 Chinese women diagnosed with stage 0 to III primary breast cancer at age 25 to 64 years who were recruited between 1996 and 1998 for the Shanghai Breast Cancer Study and followed for a median of 5.2 years. The Kaplan-Meier method and Cox model were used to evaluate the genotype and survival association. RESULTS: After adjustment for known prognostic factors for breast cancer, patients homozygous for the 4G allele had significantly poorer disease-free survival [hazard ratio (HR), 1.7; 95% confidence interval (95% CI), 1.1-2.4] and overall survival (HR, 1.5; 95% CI, 1.0-2.3) than those homozygous for the 5G allele. The association was more evident in patients with advanced disease. The HRs (95% CI) were 3.5 (1.4-9.0) for disease-free survival and 3.1 (1.1-8.3) for overall survival in stage III patients. CONCLUSIONS: The PAI-1 4G/5G polymorphism may be a prognostic marker for young and middle-aged Chinese breast cancer patients.

Zhang X; Shu XO; Cai Q; Ruan Z; Gao YT; Zheng W

2006-10-01

352