scholarly journals Enhanced Angiogenic Capacity and Urokinase-Type Plasminogen Activator Expression by Endothelial Cells Isolated from Human Endometrium

2001 ◽  
Vol 86 (7) ◽  
pp. 3359-3367 ◽  
Author(s):  
Pieter Koolwijk ◽  
Kitty Kapiteijn ◽  
Bibi Molenaar ◽  
Erik van Spronsen ◽  
Bea van der Vecht ◽  
...  

The endometrium is a tissue unique for its cyclic destruction and rapid regeneration of blood vessels. Angiogenesis, indispensable for the regeneration process, provides a richly vascularized, receptive endometrium fundamental for implantation, placentation, and embryogenesis. Human endometrial microvascular endothelial cells (hEMVEC) were isolated to better understand the properties and angiogenic behavior of these cells. Unlike human foreskin microvascular endothelial cells (hFMVEC), which proliferated better upon stimulation by basic fibroblast growth factor, hEMVEC were much more sensitive to vascular endothelial growth factor A (VEGF-A) stimulation, probably due to enhanced VEGF receptor 2 expression. In addition, hEMVEC displayed an enhanced expression of the urokinase-type plasminogen activator (u-PA) compared with hFMVEC. No differences were found in tissue-type PA, PA inhibitor-1, and u-PA receptor expression. The high expression of u-PA by hEMVEC was also found in tissue sections. hEMVEC formed capillary-like structures when cultured in 20% human serum on top of three-dimensional fibrin matrices, and VEGF-A or basic fibroblast growth factor increased this tube formation. This is in contrast with hFMVEC, which formed tubes only after simultaneous stimulation by a growth factor and tumor necrosis factor-α. The high basal level of u-PA contributes to and may explain the higher angiogenic properties of hEMVEC (in vitro).

1996 ◽  
Vol 7 (3) ◽  
pp. 369-381 ◽  
Author(s):  
M Rusnati ◽  
P Dell'Era ◽  
C Urbinati ◽  
E Tanghetti ◽  
M L Massardi ◽  
...  

Basic fibroblast growth factor (FGF-2) induces cell proliferation and urokinase-type plasminogen activator (uPA) production in fetal bovine aortic endothelial GM 7373 cells. In the present paper we investigated the role of the interaction of FGF-2 with tyrosine-kinase (TK) FGF receptors (FGFRs) in mediating uPA up-regulation in these cells. The results show that FGF-2 antagonists suramin, protamine, heparin, the synthetic peptide FGF-2(112-155), and a soluble form of FGFR-1 do not inhibit FGF-2-mediated uPA up-regulation at concentrations that affect growth factor binding to cell surface receptors and mitogenic activity. In contrast, tyrosine phosphorylation inhibitors and overexpression of a dominant negative TK- mutant of FGFR-1 abolish the uPA-inducing activity of FGF-2, indicating that FGFR and its TK activity are essential in mediating uPA induction. Accordingly, FGF-2 induces uPA up-regulation in Chinese hamster ovary cells transfected with wild-type FGFR-1, -2, -3, or -4 but not with TK- FGFR-1 mutant. Small unilamellar phosphatidyl choline:cholesterol vesicles loaded with FGF-2 increased uPA production in GM 7373 cells in the absence of a mitogenic response. Liposome-encapsulated FGF-2 showed a limited but significant capacity, relative to free FGF-2, to interact with FGFR both at 4 degrees C and 37 degrees C and to be internalized within the cell. uPA up-regulation by liposome-encapsulated FGF-2 was quenched by neutralizing anti-FGF-2 antibodies, indicating that the activity of liposome-delivered FGF-2 is mediated by an extracellular action of the growth factor. Taken together, the data indicate that a distinct interaction of FGF-2 with FGFR, quantitatively and/or qualitatively different from the one that leads to mitogenicity, is responsible for the uPA-inducing activity of the growth factor.


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