scholarly journals Increase in cytosolic calcium upregulates the synthesis of type 1 plasminogen activator inhibitor in the human histiocytic cell line U937

Blood ◽  
1996 ◽  
Vol 87 (1) ◽  
pp. 162-173
Author(s):  
F Peiretti ◽  
C Fossat ◽  
F Anfosso ◽  
MC Alessi ◽  
M Henry ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Plasminogen Activator Inhibitor ◽  
Cytosolic Calcium ◽  
Calcium Mobilization ◽  
U937 Cells ◽  
Histiocytic Cell ◽  
Dose Dependent ◽  
Activator Inhibitor ◽  
Pai 1

In the U937 histiocytic cell line, we investigated the effect of calcium-mobilizing agents with or without tumor necrosis factor-alpha (TNF) on the regulation of the synthesis of plasminogen activator inhibitor-type 1 (PAI-1). Cultured U937 cells were stimulated with ionophore A23187 and thapsigargin with or without TNF. The response was analyzed in terms of cytosolic calcium mobilization, PAI-1 accumulation in the medium, and PAI-1 mRNA expression. The study was extended to urokinase (uPA) secretion and surface expression of its receptor (uPAR). Using Fluo-3 as a calcium-indicator dye to measure cytosolic calcium mobilization, we showed by flow cytometry that both agents mobilized calcium in a dose-dependent manner. TNF provoked a slight calcium mobilization that was also observed by digital imaging microscopy. Association of TNF with the calcium-mobilizing agents potentiated the calcium mobilization. Both calcium-mobilizing agents induced at 18 hours a dose-dependent accumulation of PAI-1 in culture medium, whereas uPA was not affected. TNF alone induced a more marked accumulation of PAI-1 than of uPA. Association of TNF with the agents induced a PAI-1 response that was more than additive of the two, whereas the secretion of uPA was not enhanced. Membrane expression of uPAR, measured by flow cytometry, tended to be slightly augmented by the calcium-mobilizing agents only. All the treatments resulted in a significant increase in PAI-1 mRNA level at 3 hours after the stimulation, which was very marked when calcium-mobilizing agents were present. Incubation of U937 cells in a calcium-free medium totally prevented both the mRNA expression and accumulation of PAI-1 induced by calcium-mobilizing agents and, to lesser extent, that induced by TNF. The increase in PAI-1 mRNA expression did not require de novo protein synthesis, as cycloheximide did not suppress the increase in PAI-1 mRNA induced by calcium-mobilizing agents. It is concluded that, in U937 cells, calcium triggers a pathway that upregulates PAI-1 synthesis and positively interacts with the TNF-induced pathway that stimulates PAI-1 synthesis. As uPA and uPAR were differently affected, it is suggested that an increase in cytosolic calcium leads to a reduced pericellular proteolysis.

scholarly journals Increase in cytosolic calcium upregulates the synthesis of type 1 plasminogen activator inhibitor in the human histiocytic cell line U937

Blood ◽  
1996 ◽  
Vol 87 (1) ◽  
pp. 162-173 ◽  
Author(s):  
F Peiretti ◽  
C Fossat ◽  
F Anfosso ◽  
MC Alessi ◽  
M Henry ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Plasminogen Activator Inhibitor ◽  
Cytosolic Calcium ◽  
Calcium Mobilization ◽  
U937 Cells ◽  
Histiocytic Cell ◽  
Dose Dependent ◽  
Activator Inhibitor ◽  
Pai 1

Abstract In the U937 histiocytic cell line, we investigated the effect of calcium-mobilizing agents with or without tumor necrosis factor-alpha (TNF) on the regulation of the synthesis of plasminogen activator inhibitor-type 1 (PAI-1). Cultured U937 cells were stimulated with ionophore A23187 and thapsigargin with or without TNF. The response was analyzed in terms of cytosolic calcium mobilization, PAI-1 accumulation in the medium, and PAI-1 mRNA expression. The study was extended to urokinase (uPA) secretion and surface expression of its receptor (uPAR). Using Fluo-3 as a calcium-indicator dye to measure cytosolic calcium mobilization, we showed by flow cytometry that both agents mobilized calcium in a dose-dependent manner. TNF provoked a slight calcium mobilization that was also observed by digital imaging microscopy. Association of TNF with the calcium-mobilizing agents potentiated the calcium mobilization. Both calcium-mobilizing agents induced at 18 hours a dose-dependent accumulation of PAI-1 in culture medium, whereas uPA was not affected. TNF alone induced a more marked accumulation of PAI-1 than of uPA. Association of TNF with the agents induced a PAI-1 response that was more than additive of the two, whereas the secretion of uPA was not enhanced. Membrane expression of uPAR, measured by flow cytometry, tended to be slightly augmented by the calcium-mobilizing agents only. All the treatments resulted in a significant increase in PAI-1 mRNA level at 3 hours after the stimulation, which was very marked when calcium-mobilizing agents were present. Incubation of U937 cells in a calcium-free medium totally prevented both the mRNA expression and accumulation of PAI-1 induced by calcium-mobilizing agents and, to lesser extent, that induced by TNF. The increase in PAI-1 mRNA expression did not require de novo protein synthesis, as cycloheximide did not suppress the increase in PAI-1 mRNA induced by calcium-mobilizing agents. It is concluded that, in U937 cells, calcium triggers a pathway that upregulates PAI-1 synthesis and positively interacts with the TNF-induced pathway that stimulates PAI-1 synthesis. As uPA and uPAR were differently affected, it is suggested that an increase in cytosolic calcium leads to a reduced pericellular proteolysis.

Binding of urokinase to plasminogen activator inhibitor type-1 mediates cell adhesion and spreading

1997 ◽  
Vol 110 (9) ◽  
pp. 1091-1098
Author(s):  
E. Planus ◽  
G. Barlovatz-Meimon ◽  
R.A. Rogers ◽  
S. Bonavaud ◽  
D.E. Ingber ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Plasminogen Activator Inhibitor Type ◽  
Inhibitor Type ◽  
Activator Inhibitor Type ◽  
Dose Dependent ◽  
Activator Inhibitor ◽  
Pai 1

Urokinase plasminogen activator and its receptor are both found at the surface of the cell membrane in many cell types. The plasminogen activator inhibitor type-1 (PAI-1) is often associated with the extracellular matrix. The spatial localization of these three molecules could account for their involvement in cell adhesion and/or migration. We have shown previously that the urokinase receptor mediates mechanical force transmission across the cell surface to the cytoskeleton. Here we investigated whether immobilized plasminogen activator inhibitor type 1 (PAI-1) could regulate cell spreading and cytoskeleton reorganization. Serum deprived human myogenic cells were plated in serum free medium onto bacteriologic dishes precoated with different extracellular matrix ligands (fibronectin, vitronectin, or type 1 collagen) or PAI-1 at increasing concentrations. The number of adherent cells and their projected area were quantitated after 3 hours of plating. PAI-1 promoted cell adhesion and spreading in a dose dependent manner. Addition of antibodies to PAI-1 inhibited the adhesion on PAI-1 coated dishes in a dose dependent way. The PAI-1 mediated cell adhesion required the presence of urokinase at the cell surface. Removal of the glycosylphosphatidylinositol (GPI)-linked proteins abolished cell adhesion on PAI-1 dish, suggesting its dependence on the presence of the urokinase receptor, a GPI-linked receptor. Furthermore, addition of antibodies against alpha v beta3 integrin completely inhibited cell adhesion on PAI-1, suggesting that alpha v beta3 might be the transmembrane molecule that physically connects the complex of PAI-1, urokinase, and urokinase receptor to the cytoskeleton. Visualization of spread cells stained for filamentous actin with confocal microscopy showed a dose-dependent increase of filopodia on PAI-1 coated dishes and cytoskeletal reorganization, suggesting a migratory profile. These data indicate that PAI-1 plays a direct role in dynamic cell adhesion particularly at the leading edge, where increased levels of urokinase plasminogen activator (uPA) and its receptor (uPAR) are localized in migrating cells. Immobilized PAI-1 could therefore serve to bridge the cell surface with the extracellular matrix via the formation of a multimolecular complex that includes alpha v beta3 integrins in myogenic cells.

Limited Proteolysis of Vitronectin by Plasmin Destroys Heparin Binding Activity

1991 ◽  
Vol 66 (03) ◽  
pp. 310-314 ◽  
Author(s):  
David C Sane ◽  
Tammy L Moser ◽  
Charles S Greenberg
Keyword(s):  
Limited Proteolysis ◽  
Plasminogen Activator Inhibitor ◽  
Binding Activity ◽  
Binding Domain ◽  
Heparin Binding ◽  
Inhibitor Type ◽  
Activator Inhibitor Type ◽  
Activator Inhibitor ◽  
Pai 1

SummaryVitronectin (VN) stabilizes plasminogen activator inhibitor type 1 (PAI-1) activity and prevents the fibrin(ogen)-induced acceleration of plasminogen activation by t-PA. These antifibrinolytic activities as well as other functions are mediated by the glycosaminoglycan (GAG) binding domain of VN. Since the GAG binding region is rich in arginyl and lysyl residues, it is a potential target for enzymes such as plasmin. In this paper, the dose and time-dependent proteolysis of VN by plasmin is demonstrated. The addition of urokinase or streptokinase (200 units/ml) to plasma also produced proteolysis of VN. With minimal proteolysis, the 75 kDa band was degraded to a 62-65 kDa form of VN. This minimal proteolysis destroyed the binding of [3H]-heparin to VN and reversed the neutralization of heparin by VN.Thus, the plasmin-mediated proteolysis of the GAG binding activity of VN could destroy the antifibrinolytic activity of VN during physiologic conditions and during thrombolytic therapy. Furthermore, other functions of VN in complement and coagulation systems that are mediated by the GAG binding domain may be destroyed by plasmin proteolysis.

Adiponectin is inversely related to plasminogen activator inhibitor type 1 in patients with stable exertional angina

2004 ◽  
Vol 91 (05) ◽  
pp. 1026-1030 ◽  
Author(s):  
Hidetomo Maruyoshi ◽  
Tohru Funahashi ◽  
Shinzo Miyamoto ◽  
Jun Hokamaki ◽  
Hirofumi Soejima ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Plasma Levels ◽  
Plasminogen Activator Inhibitor ◽  
Plasminogen Activator Inhibitor Type ◽  
Exertional Angina ◽  
Inhibitor Type ◽  
Activator Inhibitor Type ◽  
Activator Inhibitor ◽  
Pai 1

SummaryAdipose tissue is a secretory organ producing a variety of bioactive substances, such as adiponectin. Adiponectin has antiatherogenic properties while plasminogen activator inhibitor type 1 (PAI-1) is closely involved in the development of atherosclerosis. The relationship between adiponectin and PAI-1 in patients with coronary artery disease (CAD) has not been clarified. This study examined plasma levels of adiponectin and PAI-1 in 64 patients with stable exertional angina (SEA) and 65 patients with the chest pain syndrome (CPS). Plasma logadiponectin levels were significantly lower in patients with SEA (0.62±0.08 µg/dL) compared to those with CPS (0.86± 0.05 µg/dL) (p<0.0001). The plasma levels of log-PAI-1 were significantly higher in patients with SEA (1.23±0.18 ng/mL) compared to those with CPS (1.15±0.22 ng/mL) (p<0.05). Plasma log-adiponectin levels correlated negatively with diabetes mellitus (DM), body mass index (BMI), log-PAI-1 (r=−0.284, p<0.001), triglyceride (TG), and remnant-like particles cholesterol (RLP-C), and positively with high-density lipoprotein cholesterol (HDL-C) levels. Plasma levels of log-PAI-1 correlated positively with DM, BMI, TG and RLP-C levels, and negatively with HDL-C levels. Multiple logistic regression analysis identified sex, angina pectoris, and PAI-1 as independent determinants of hyperadiponectinemia (p<0.05). Adiponectin is inversely related to PAI-1. DM, BMI, TG, HDL-C, and RLP-C are common mediators between adiponectin and PAI-1, and treatment for common mediators may prevent the development of CAD by reducing PAI-1 and increasing adiponectin levels.

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