Concomitant secretion by transformed SVWI38-VA13-2RA cells of plasminogen activator(s) and substance(s) which prevent their detection

Roblin, Richard O.; Young, Paul; Bell, T E

doi:10.1016/0006-291x(78)90591-0

Cited by 43 publications

(18 citation statements)

References 11 publications

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“…Furthermore, these inhibitors appear to differ between different cell types. The secretion of Uk inhibitors by murine macrophages, which also synthesize a Uk-type PA (15,16, manuscript in preparation), as well as by hepatoma tissue culture cells (36), endothelial cells (37)(38)(39), and other cell types (40)(41)(42), further underlines the possible generality of these phenomena.…”

Section: Discussionmentioning

confidence: 93%

Concomitant secretion of prourokinase and of a plasminogen activator-specific inhibitor by cultured human monocytes-macrophages.

Vassalli¹,

Dayer²,

Wohlwend³

et al. 1984

The Journal of Experimental Medicine

410

195

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The plasminogen activator (PA) produced by freshly purified human monocytes-macrophages and histiocytic, lymphoma-derived U 937 cells was analyzed by zymography after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and found to migrate with an apparent Mr of 55,000, identical to that of urokinase (Uk). By immunoprecipitation with antibodies specific for the two different types of PA, the enzyme was shown to be immunologically related to urokinase, and not to tissue PA. Urokinase was secreted in the form of the inactive Mr 55,000 zymogen prourokinase , and could be converted to the active Mr 55,000 enzyme by limited proteolysis with plasmin. Conditioned media from cultures of U 937 cells and monocytes-macrophages inhibited the fibrinolytic activity of exogenously added urokinase. Using [125I]-labeled urokinase we observed the formation of an enzyme-ligand complex, which was not dissociated by boiling in SDS and migrated with an apparent Mr 40,000 daltons higher than the free enzyme; since complexed urokinase was functionally inactivated as a PA, the ligand is an inhibitor of urokinase. This inhibitor is different from fibroblast-produced protease- nexin , in that it did not interact with thrombin. These results suggest that plasminogen activation by mononuclear phagocytes can be modulated through the secretion of both (pro)enzyme and a specific inhibitor.

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Section: Discussionmentioning

confidence: 93%

Concomitant secretion of prourokinase and of a plasminogen activator-specific inhibitor by cultured human monocytes-macrophages.

Vassalli¹,

Dayer²,

Wohlwend³

et al. 1984

The Journal of Experimental Medicine

410

195

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“…They are classified into tissue-and urokinase-type activators that differ in molecular weight and immunological reactivity. Enhanced activator production has been induced by tumor virus infection of certain cells in culture (28,32,37), and activator activity has been regulated by glucocorticoid (27). Recently, the induction of a large amount of the urokinase was demonstrated in DNA-repair-deficient cells that had undergone UV irradiation (5,21).…”

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confidence: 99%

A monoclonal antibody against human urokinase: Characterization of the epitope and its localization in human kidney.

Nakamura

Takahashi

Naora

et al. 1984

Cell Struct. Funct.

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ABSTRACT. Monoclonal antibodies against human plasminogen activator urokinase have been produced. A G62 hybridoma-producing antibody (IgG) was purified on a DEAE-cellulose column, and it proved useful for the measurement, identification and purification of antigens that had approximate molecular weights of 55-and 33-Kdaltons.For immunochemical measurements and purification, a competitive enzymelinked immunosorbent assay (ELISA) and affinity chromatography using antibody-immobilized Sepharose 4B were developed. The ELISA has sensitivity to 20 p mole antigen molecules. The binding capacity of the antigen on the affinity column was evaluated on SDS-polyacrylamide slab gels as well as by fibrin autography and ELISA. Results showed that there was quantitative purification with no loss of enzyme activity in the one-step procedure.Western blotting and affinity binding showed antigenic bands with apparent molecular weights of 55-and 33-Kdaltons. Because the 55-Kdalton form contains 33-and 22-Kdalton components connected by a disulfide bond, the epitope domain is present on the 33-Kdalton chain.Using this antibody, we examined human kidney sections by direct immunofluorescence to locate the antigen. It was found in epithelial cells of convoluted segments, in glomerulus cells and in capillary endothelial cells, evidence that renal tubular cells synthesize the antigen which then is secreted in urine.

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“…Both types are produced by a variety of cultured cell types, derived from normal as well as neoplastic tissue (6,10,15,22,26,(32)(33)(34)(35)(43)(44)(45). It is doubtful, however, whether the cultured cells in this respect are always representative of the cells in the intact organism.…”

mentioning

confidence: 99%

“…At least some plasminogen activators are themselves produced as inactive proenzymes (20)(21)(22)(23) . The process leading to generation of plasmin is thus a cascade reaction characterized by amplification of the proteolytic activity and regulated by enhancing and inhibitory factors (7,9,(24)(25)(26).…”

mentioning

confidence: 99%

“…Enzyme histochemical studies have been performed using an agarose overlay technique with plasminogen-rich fibrin (7,8,(46)(47)(48). This method often has shortcomings, however, related to a low degree of resolution, a lack of distinction between the two types ofactivators, the occurrence of inactive proenzymes of the plasminogen activators, and the interference of inhibitors of plasminogen activators and plasmin (9,(20)(21)(22)(23)(24)(25)(26).…”

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confidence: 99%

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Distribution of urokinase-type plasminogen activator immunoreactivity in the mouse.

Larsson¹,

Skriver²,

Nielsen³

et al. 1984

The Journal of Cell Biology

177

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Immunocytochemistry, using rabbit antibodies to a urokinase-type 48-Kdalton Mr mouse plasminogen activator, showed that enzyme immunoreactivity is widely distributed in the normal mouse. Strong staining was obtained in widely disseminated connective tissue cells with a fibroblast-like morphology . Such cells occurred in high numbers in the lamina propria mucosae of the gastrointestinal tract, and in moderate numbers in the connective tissue septa of the pancreas . A few such cells were detected around the larynx, trachea, and bronchi . Immunoreactivity also occurred in epithelial cells of the proximal and distal kidney tubules, the ductus deferens, and in pulmonary pneumocytes . In addition, presumably extracellular staining was seen irregularly along the basement membrane and fibrillar structures in the lamina propria of the small and large intestines . Moreover, decidual cells of the mouse placenta stained strongly, and a moderate staining was observed in epithelial cells of involuting mammary glands, but not in those of noninvoluting glands . No immunoreactivity was observed in endothelial cells.Control experiments included absorption of the antibodies against highly-purified mouse plasminogen activator and the corresponding proenzyme, and the finding of a good correspondence between the number of immunoreactive cells and measurable enzymatic activity determined in adjacent tissue sections . Separation by SDS PAGE followed by immunoblotting revealed only one immunochemically stainable protein band with Mr^-48 Kdaltons in extracts from tissues showing immunoreactivity .

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Concomitant secretion by transformed SVWI38-VA13-2RA cells of plasminogen activator(s) and substance(s) which prevent their detection

Cited by 43 publications

References 11 publications

Concomitant secretion of prourokinase and of a plasminogen activator-specific inhibitor by cultured human monocytes-macrophages.

Concomitant secretion of prourokinase and of a plasminogen activator-specific inhibitor by cultured human monocytes-macrophages.

A monoclonal antibody against human urokinase: Characterization of the epitope and its localization in human kidney.

Distribution of urokinase-type plasminogen activator immunoreactivity in the mouse.

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