Medium optimization for the production of fibrinolytic enzyme by Paenibacillus sp. IND8 using response surface methodology.

Production of fibrinolytic enzyme by a newly isolated Paenibacillus sp. IND8 was optimized using wheat bran in solid state fermentation. A 2(5) full factorial design (first-order model) was applied to elucidate the key factors as moisture, pH, sucrose, yeast extract, and sodium dihydrogen phosphate. Statistical analysis of the results has shown that moisture, sucrose, and sodium dihydrogen phosphate have the most significant effects on fibrinolytic enzymes production (P < 0.05). Central composite design (CCD) was used to determine the optimal concentrations of these three components and the experimental results were fitted with a second-order polynomial model at 95% level (P < 0.05). Overall, 4.5-fold increase in fibrinolytic enzyme production was achieved in the optimized medium as compared with the unoptimized medium.

[Sialic acids and O-acetyl groups as markers of biological activity of microbial polysaccharides in plague and cholera agents].

AIM: To determine sialic acids and O-acetyl groups content in Yersinia pestis and Vibrio cholerae antigens in order to establish their association with biological activity. MATERIALS AND METHODS: The following antigens of Y. pestis EV NIIEG strain--capsular antigen (F1), major somatic antigen (MSA), lipopolysaccharide (LPS), Pla-protease, allergen pestin PP--as well as O-antigens (O-AG) of V. cholerae serogroups O1 and O139 were used in the study. Sialic acids were identified by the thiobarbituric method, and O-acetyl groups--according to Alicino. Specific polysaccharides in the MSA and O-antigens were detected by the immunodiffusion assay. RESULTS: Sialic acids were found in LPS, Pla-protease, allergen pestin PP, and all cholera O-AG; their absence was demonstrated in MSA and F1. O-acetyl groups were identified in cholera O-AG of both studied serogroups as well as in LPS, Pla-protease, MSA and pestin PP of Y. pestis. Tendency to correlation between O-acetyl groups content in MSA and serological activity titer was observed. CONCLUSION: Sialic acids and O-acetyl groups identified in carbohydrate-containing antigens of Y. pestis and V. cholerae could be characterized as reaction-active markers of pathogenetic mechanisms of cholera and plague infections as well as immunochemical activity of microbial polysaccharides.

Streptococcal cell walls and synovial cell activation. Stimulation of synovial fibroblast plasminogen activator activity by monocytes treated with group A streptococcal cell wall sonicates and muramyl dipeptide.

Group A streptococcal peptidoglycan has previously been shown to be arthritogenic in rats and has been implicated as a structure present in a class of possible etiologic agents for rheumatoid arthritis. The present study reports that conditioned medium from human monocytes, after interaction with cell wall sonicates of four group A streptococcal strains, stimulates the plasminogen activator (PA) activity of nonrheumatoid synovial fibroblasts. Low concentrations of N-acetylmuramyl-L-alanyl-D isoglutamine (muramyl dipeptide) can also generate this synovial activator (SA) activity from human monocytes. Preliminary biochemical data suggest that the SA activity is distinct from interferon-gamma, interleukin 1, and interleukin 2. These results indicate that agents that are arthritogenic in rats can modulate human synovial fibroblast functions via monocytes. The findings are proposed to have possible significance for an understanding of the cellular interactions involved in the formation and function of the rheumatoid pannus, because PA has been invoked as possibly being generally important for the processes of cell migration, tissue remodeling, and inflammation.

Production of plasminogen activator by human natural killer cells. Large granular lymphocytes.

In this report we have used highly purified populations of natural killer (NK) cells: large granular lymphocytes (LGL). This study demonstrates that freshly isolated and interleukin 2-cultured LGL produce the specific neutral serine protease, plasminogen activator (PA). We have found that the enzyme is expressed in both an extracellular form as well as in a cell-associated form. Upon subcellular distribution the latter form of the enzyme is associated with a cell-surface membrane-enriched fraction. LGL PA exists in multiple molecular weight forms ranging from 100,000 to 26,000. Interferon (IFN), the major positive regulator of NK cytolytic activity, caused a substantial enhancement of cell-associated, but not extracellular, PA. In contrast, LGL isolated from patients with Chediak-Higashi syndrome, who are known to be defective in NK activity, displayed low PA activity, altered morphology, and low NK killing relative to LGL isolated from normal donors. The possible role of LGL PA in the lysis of tumor cells by NK cells, either directly or indirectly, is discussed.

Plasminogen activator in mammalian skeletal muscle: characteristics of effect of denervation on urokinase-like and tissue activator.

Analyses were made of the fibrinolytic, plasminogen-activating system in skeletal muscle to determine if a regulating influence of the nerve could be detected on these enzymes. Young male mice underwent right sciatic neurectomy. Extracts were prepared from denervated muscle at 2-17 d after axotomy and compared with controls. Using a cascade-style biochemical assay (Rånby, M., B. Norrman, and P. Wallén, 1982, Thromb. Res., 27:743-748) we found that low levels of plasminogen activator (PA) were present in adult, innervated mouse muscle, but that denervation resulted in a marked time-dependent increase in enzyme activity. Qualitative separation showed an eightfold increase in urokinase-like PA with moderate elevation of tissue PA activity after 10 d. Fibrin zymography (Granelli-Piperno, A., and E. Reich, 1978, J. Exp. Med., 148:223-234) revealed clear zones of lysis corresponding to molecular masses of 48 kD for urokinase-like PA and 75 kD for tissue PA, consistent with the molecular masses found for these enzymes in other tissues of the mouse (Danø, K., P. A. Andreasen, J. Grøndahl-Hansen, P. Kristensen, L. S. Nielsen, and L. Skriver, 1985, Adv. Cancer Res., 44:139-266). In other studies we have shown that PA-activated plasmin readily attacks critical adhesive basement membrane molecules. The present results indicate that enzymes involved in plasminogen activation, particularly urokinase-like PA, rapidly increase after axotomy, suggesting they may have a role early in muscle denervation. Similar alterations in PA activity might underlie the elimination of polyneuronal innervation during mammalian muscle development. Certain neuromuscular diseases may also involve activation of these enzymes, resulting in degradation of basement membrane zone components and, therefore, warrant further study.

Effects of sulfonylureas on the synthesis and secretion of plasminogen activator from bovine aortic endothelial cells.

The effects of sulfonylureas on the production of plasminogen activator (PA) and antiactivator (PAI) were investigated using bovine aortic endothelial cells. All compounds studied stimulated PA release (1.3- to 5.2-fold), with glipizide being the most potent, followed by tolazamide, chlorpropamide, and tolbutamide, in that order, while glyburide was the least effective. Both tissue-type and urokinase-type PA production was enhanced. Studies using metabolic inhibitors indicated that both RNA and protein syntheses are required for the sulfonylurea-mediated stimulation of PA release. In addition to continuous release of the two PAs, there was also a continuous release of a single PAI, which did not show an increase after the sulfonylureas. These results suggest that, in addition to their beneficial effects in the treatment of diabetes mellitus, some sulfonylurea compounds may also have significant thrombolytic effects. These results also suggest that pharmacological enhancement of PA production by vascular endothelial cells may be a promising antithrombotic mechanism.

Thrombolysis with human extrinsic (tissue-type) plasminogen activator in dogs with femoral vein thrombosis.

Extrinsic (tissue-type) plasminogen activator (plasminogen activator) was isolated either as a single-chain or as a two-chain molecule from the culture medium of a human melanoma cell line. The thrombolytic activity of both molecular forms of activator was investigated in beagle dogs with an experimental femoral vein thrombosis and compared with that of urokinase. The 125I-fibrinogen-labeled thrombus was formed in an isolated 4-cm segment of the vein, aged for 30 min, and the thrombolytic substances were infused over a 4-h period. The degree of thrombolysis was measured 2 h later as the difference between the injected and recovered 125I. In six control animals with a saline infusion the extent of thrombolysis was 16.3 +/- 3.8% (mean +/- SEM), in five dogs receiving 100,000 IU urokinase, 17.4 +/- 3.7% (P less than 0.4) and in four dogs with 1,000,000 IU urokinase 40.6 +/- 4.8% (P less than 0.001). Infusion of 100.000 IU single-chain plasminogen activator in five dogs resulted in 3.5 +/- 7.8% lysis (P less than 0.05) and of 100,000 IU two-chain plasminogen activator in five dogs in 60.1 +/- 10.8% (P less than 0.001). Infusion of 300,000 IU one-chain plasminogen activator yielded 57.5% lysis and of the same amount of two-chain plasminogen activator 72.9%. Significant activation of plasminogen, consumption of alpha 2-antiplasmin, and fibrinogen breakdown in plasma was only observed in animals receiving the high doses of urokinase but not in the saline, plasminogen activator, or the low-dose urokinase groups. It is thus concluded that in this thrombosis model human extrinsic plasminogen activator has a higher specific thrombolytic effect that urokinase. Plasminogen activator also appears to induce thrombolysis without systemic fibrinolytic activation and fibrinogen breakdown.

Transport of urokinase across the intestinal tract of normal human subjects with stimulation of synthesis and/or release of urokinase-type proteins.

Oral administration of clinical-type high molecular weight urokinase (HMW-UK) in a single dose of 30,000-60,000 International Units (IU) in enteric-coated capsules, in a group of normal human subjects, induced a plasma fibrinolytic state suggesting transport of HMW-UK across the intestinal tract. Other groups of human subjects were given a single dose of 120,000 IU daily of pure HMW-UK for 1 d and 7 d together with a placebo dose, all of the ingredients except urokinase (UK), daily for 7 d. UK-type proteins were isolated from the plasma of blood samples drawn 6 h after administration of the final dose, by a sequential two-step affinity chromatography method first with [N alpha-(epsilon-aminocaproyl)-DL-homoarginine hexylester]-Sepharose and second with a specific rabbit anti-HMW-UK-IgG-Sepharose. The yield of UK-type proteins from the 7-d group, 0.79 mg/dl, was approximately twofold greater than that obtained from either the placebo or 1-d groups. The specific plasminogen activator activity of the 1-d and 7-d groups were similar, 508 and 537 IU/mg protein, respectively; negligible plasminogen activator activity could be detected in the placebo group. The kinetics of activation parameters of human Glu-plasminogen of the UK-type protein, isolated from the 1-d group, were similar to those obtained with urinary HMW-UK. The UK-type proteins isolated only from the 7-d group showed, in sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, a major protein band of molecular weight 53,000 in the same position as HMW-UK. In addition, two other major protein bands of approximately 140,000 and approximately 120,000 mol wt were found in the 7-d placebo-, and 1-d groups, and also in the 7-d group. The 53,000 mol wt protein, about 50% of the total protein in the 7-d group, was further purified by preparative SDS-polyacrylamide gel electrophoresis, and found to be a two-chain protein with a specific activity of 1,241 IU/mg protein. The protein showed common antigenic determinants with urinary HMW-UK. The oral administration of 120,000 IU HMW-UK to human subjects for 7 d stimulated the synthesis of a UK-type protein of 53,000 mol wt, probably the zymogen, from either the liver or vascular endothelium, which was released into the circulation, and converted into active UK by circulating plasmin. The induction of the fibrinolytic state produced the conversion of native circulating Glu-plasminogen into the degraded Lys-plasminogen form, which was found in large amounts in the plasma of the 7-d group. The new plasma components, e.g., the 53,000-mol wt UK-zymogen and Lys-plasminogen, could play an important role in clot resolution of the fibrin-thrombus in thromboembolic diseases. Oral administration of HMW-UK has been shown to be clinically effective in patients with cerebral thrombosis in a multicenter double blind study.

Isolation and absolute configuration of SMTP-0, a simplest congener of the SMTP family nonlysine-analog plasminogen modulators.

SMTP-0, a new simple congener of the SMTP nonlysine-analog plasminogen modulators, was isolated from a culture of Stachybotrys microspora. Based on the physico-chemical data, SMTP-0 was shown to be an enantiomer of the antimicrobial compound stachybotrin B. The absolute configuration of SMTP-0 was determined by the modified Mosher method. The stereochemistry was further confirmed using an epimer of SMTP-0. Unlike most SMTPs with an amino acid side chain linked to the nitrogen atom of the lactam moiety, SMTP-0, which lacks the N-linked side chain, showed no plasminogen modulator activity.

Stachybotrydial selectively enhances fibrin binding and activation of Glu-plasminogen.

Stachybotrydial, a triprenyl phenol metabolite from a fungus, has a plasminogen modulator activity selective to Glu-plasminogen. Stachybotrydial enhanced fibrin binding and activation of Glu-plasminogen (2- to 4-fold enhancement at 60-120 microM) but not of Lys-plasminogen. Approximately 1.2-1.6 moles of [3H]stachybotrydial bound to Glu-plasminogen to exert such effects. The selective modulation of the Glu-plasminogen function by stachybotrydial may be related to alteration of its conformational status.

Adhesive properties of the purified plasminogen activator Pla of Yersinia pestis.

The beta-barrel outer membrane protease Pla from Yersinia pestis is an important virulence factor in plague and enables initiation of the bubonic plague. Pla is a multifunctional protease whose expression also enhances bacterial adherence to extracellular matrix. It has remained uncertain whether the increase in cellular adhesiveness results from modification of the bacterial surface by Pla, or whether the Pla molecule is an adhesin. Pla was purified as a His6-fusion protein from Escherichia coli and reconstituted with lipopolysaccharide to an enzymatically active form. Purified His6-Pla was coated onto fluorescent micro-particles (FMPs) that expressed plasminogen activity. Pla-coated FMPs also bound to laminin and to reconstituted basement membrane (Matrigel) immobilized on permanox slides, whereas only poor activity was seen with lipopolysaccharide-coated FMPs or bovine serum albumin-coated FMPs. The results show that the Pla molecule has intrinsic adhesive properties and that purified transmembrane proteins coated onto FMPs can be used for functional assays.

Interaction of a plasminogen activator proteinase, LV-PA with human alpha2-macroglobulin.

Lachesis venom plasminogen activator (LV-PA) is a 33-kDa serine proteinase isolated from bushmaster (Lachesis muta muta) snake venom, which activates the fibrinolytic system in vitro. This study has examined the effect of the plasma proteinase inhibitor alpha2-macroglobulin (alpha2-M) towards LV-PA and compares it with the effect on tissue type plasminogen activator (t-PA). The proteolytic activity of LV-PA alone or previously incubated with human plasminogen (Plg) on the large molecular mass protein substrates, dimethylcasein (DMC) and fibrinogen (Fg) was completely inhibited by human alpha2-M. However, the synthetic peptides Tos-Gly-Pro-Lys-pNA and H-D-Pro-Phe-Arg-pNA (S-2302) were hydrolyzed with almost no reduction in rate. At pH 7.4 and 37 degrees C the proteinase (0.15 microM over 15 min) interacted with alpha2-M, and each mole of alpha2-M bound 2 mol of enzyme. Sodium dodecyl sulfate gel electrophoresis of reduced samples showed that the interaction of alpha2-M with either LV-PA or t-PA preincubated with Plg resulted in the formation of approximately 90 kDa fragments and high molecular mass complexes (Mr 180 kDa), generated by the incubation mixture (LV-PA or t-PA) and Plg. The data suggest that LV-PA is a direct-type PA and its fibrinolytic effect can be reduced by alpha2-M in vivo.

Activity and nature of plasminogen activators associated with the casein micelle.

In fresh milk, plasminogen, the zymogen form of plasmin (PL), is the predominant form. Therefore, plasminogen activators (PA) can contribute significantly to PL activity in milk. Both tissue-type PA (tPA) and urokinase-type PA (uPA) exist in milk; however, contradictory findings have been reported for which type of PA is most closely associated with the casein micelles. Little is known about the factors that might lead to variations in the individual activities of the PA. The objective of this work was therefore to investigate possible factors that might affect the association of tPA and uPA with the casein micelle and their activities thereafter. Plasminogen activators were isolated from milk samples with different somatic cell counts following 2 different isolation protocols. Determination of uPA, tPA, and PL activities was carried out quantitatively following chromogenic assays using 2 different substrates, and qualitatively using specialized sodium dodecyl sulfate-PAGE. Different isolation methods and conditions led to differences in uPA, tPA, and PL activities. Urokinase-type PA activity was significantly higher in PA fractions isolated from milk with high somatic cell counts than from milk with low somatic cell counts. Activity results indicated that in pasteurized milk uPA could dissociate from the somatic cells and bind to casein. Moreover, a high level of PL in isolated PA fractions contributed to significantly enhanced PA activities. Overall, results confirmed the association of both uPA and tPA with the casein micelle; however, their amounts, activities, and molecular weights varied based on the nature of the milk and methods of separation, with uPA being the PA with greater potential to affect plasminogen activation in milk.

Plasminogen activator content of human colon tumors and normal mucosae: separation of enzymes and partial purification.

Plasminogen activator content was determined quantitatively in extracts of 23 pairs of surgically removed colon tumors and adjacent normal mucosa specimens. The activator content averaged 4.4 times higher in the tumor samples than in the corresponding normal tissue. Polyps removed with the adenocarcinomas gave values intermediate between those for tumors and those for the normal mucosae. The enzyme content of the group of tumors that showed invasive propagation or metastatic spread was significantly higher (P < 0.05) than was the enzyme content of the group not manifesting these conditions. Activator activity of the tumor extracts was completely inhibited by rabbit antibody formed against human urokinse. The activity of the normal mucosae was variably inhibited, suggesting the presence of several kinds of activator in normal tissues. The activator from the normal tissues could be separated into a completely refractory fraction and a completely inhibitable fraction by means of an affinity column made of Sepharose-linked, rabbit antiurokinase antibody. The activator, eluted from this column with 1 M acetic acid in 0.5 M NaCl (pH 2.2), was highly purified and had an isoelectric point of 8.6, as does authentic urokinase. The details of the isoelectric profile of the two, however, differed. The data are discussed in relation to earlier studies on the fibrinolytic system in colon cancer.

Cryptic and active plasminogen activators secreted by line 10 tumor cells in culture.

Line 10 guinea pig carcinoma cells cultured in serum-free medium for 4 hr elaborate plasminogen activator (PA) activity that remained in the supernatant after ultracentrifugation (100,000 X g, 90 min). PA activity in line 10 conditioned medium occurred in both active and cryptic forms. The vast majority of active PA adsorbed to lysine-Sepharose and could be eluted at low pH as several activities that electrophoresed in the Mr 50,000 to 80,000 range on nonreduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A small amount of active PA, running in the Mr 50,000 to 60,000 region, and cryptic PA did not adhere to lysine-Sepharose. Treatment of lysine-Sepharose-nonadherent fractions with catalytic amounts of plasmin or trypsin induced substantial new PA activity that adsorbed to lysine-Sepharose, bound [3H]diisopropylfluorophosphate, and that electrophoresed as several bands of activity with molecular weights from 50,000 to greater than 100,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Of additional interest, the amount of active PA measured in conditioned medium was substantially increased when certain protease inhibitors, tranexamic acid, epsilon-aminocaproic acid, or Trasylol, were included during culture.

Purification and characterization of a plasminogen activator from mouse cells transformed by an oncogenic virus.

On the basis of cellular morphology, a subline of mouse sarcoma virus-infected 3T3 cells was selected which released a 48 000-dalton plasminogen activator at an approx. 40-fold higher rate than those of the parent line, and which continued to do so for several months when the cells were maintained in serum-free culture medium. Culture medium (3.5 l) containing 0.6 mg plasminogen activator per l was used to purify 620 micrograms of the enzyme 130-fold with a yield of 32% by affinity chromatography followed by anion exchange chromatography and gel filtration. Crucial for the yield was the use of a non-ionic detergent and of inhibitors of proteolysis to prevent adsorption and degradation, respectively. The purified enzyme was homogeneous as evaluated by SDS-polyacrylamide gel electrophoresis and had an isoelectric point of pH 9.2. The purified enzyme showed characteristics of a trypsin-like serine protease (labeling with [3H]diisopropylphosphorofluoridate which was prevented by p-nitrophenyl-p'-guanidinobenzoate) and converted the single chain of human plasminogen into two chains of plasmin with electrophoretic mobilities identical to those of the chains formed by non-purified enzyme and by human urokinase. In the absence of inhibitors, solutions of purified enzyme were stable for 24 h at 4 degrees C at pH 3-9.

Large-scale purification of human tissue-type plasminogen activator using monoclonal antibodies.

Tissue plasminogen activator produced by a human melanoma cell line (Bowes), was purified from large volumes of supernatant fluid using immunosorbent chromatography on monoclonal antibodies, followed by chromatography on lysine-Sepharose 4B and gel filtration on Sephadex G-150. Immunosorbents based on monoclonal antibodies were shown to be preferable to those based on polyclonal antibodies for several reasons: efficient binding and desorption, high yield along with a high degree of purification. The overall recovery was about 50%. A homogeneous sample of single-chain tissue plasminogen activator with a molecular weight of approx. 65 000 was obtained as judged by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. Amino acid sequence analysis revealed two N-terminals in equal yields, corresponding to the long and short tissue plasminogen activator structures previously reported by others. The pure preparations of tissue plasminogen activator showed specific activities of about 200 000 IU/mg protein.

Purification and characterization of human vascular plasminogen activator.

The vascular tree of the legs of human corpses was perfused with 0.15 M NaCl, and eluted with 2 M KSCN and finally with 0.15 M NaCl. The average total activity of human vascular plasminogen activator and protein eluted per leg was 29 800 Ploug units and 8.3 g respectively. Fibrin-Sepharose adsorbed the plasminogen activator activity, which could be eluted with 2 M KSCN. A small column containing from 0.5--1.9 ml of phenyl-Sepharose, normally coupled directly to the outlet of the fibrin-Sepharose column, adsorbed all the plasminogen activator activity. Elution of this hydrophobic matrix yielded a plasminogen activator preparation 17% pure judging from sodium dodecyl sulphate polyacrylamide gel electrophoresis. By this method human vascular plasminogen activator was found to have an Mr of 60 000. Upon reduction, two bands of Mr 30 000 and 31 000 were estimated. Human vascular plasminogen activator could be inhibited by diisopropylfluorophosphate. Isoelectric focusing yielded four major bands with the isoelectric points of 6.9, 7.4, 8.0 and 8.6. Human vascular plasminogen activator was found to be a relatively stable protein in purified form.

Purification and characterization of human kidney plasminogen activator dissimilar to urokinase.

The tissue activator was extracted with 2 M ammonium thiocyanate and purified by L-arginine methyl ester, concanavalin A and ion-exchange chromatographies, and Sephacryl S-200 gel filtration in buffers containing Triton X-100 and/or ammonium thiocyanate. The final preparations had specific activities of 25 000-40 000 IU/mg protein and were shown to be a single band with an apparent molecular weight of 54 00 by SDS-polyacrylamide gel electrophoresis with or without reducing agent. When subjected to isoelectric focusing, its major component had an isoelectric point of approx. 8.2 with minor components. (7.8-8.6). The purified tissue activator was a serine protease, dissimilar to urokinase in some respects including antigenicity, strong affinity to insoluble fibrin monomer and hydrolytic activities for synthetic substrates. The crude extract contained another plasminogen activator with antigen identity to urokinase, which constituted approx. 15% of the total activity in crude extract. These findings indicated that human kidney would produce at least two plasminogen activators, namely, the tissue activator as a major plasminogen activator and urokinase.

Purification and partial characterization of plasminogen activator from human uterine tissue.

A procedure was developed for the purification of a plasminogen activator from human uterine tissue. It involves six consecutive steps: (1) extraction of the plasminogen activator from delipidated uterine tissue with 0.3 M potassium acetate buffer, pH 4.2; (2) ammonium sulphate precipitation; (3) zinc chelate-agarose chromatography; (4) n-butyl-agarose chromatography; (5) concanavalin A-agarose chromatography; and (6) gel filtration on Sephadex G-150. The specific activity of the final plasminogen activator preparation was increased by a factor 4500 as compared with the crude extract. The purified plasminogen activator showed a strong tendency to adsorb to surfaces. This could be effectively prevented by Tween-80. The molecular weight of the plasminogen activator was 64 000 as estimated by gel filtration in 1.0 M NaCl and 69 000 as estimated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. The plasminogen activator consisted of two chains (molecular weights 31 000 and 38 000) connected by disulphide bridges. The smallest chain contained the serine residue of the active site as deduced from the incorporation of the tritium label of [3H]diisopropylphosphofluoridate.