Thrombin Receptor Agonist Peptide Decreases Thrombomodulin Activity in Cultured Human Umbilical Vein Endothelial Cells

1994 ◽  
Vol 199 (3) ◽  
pp. 1262-1269 ◽  
Author(s):  
Y. Maruyama ◽  
I. Maruyama ◽  
Y. Soejima
Keyword(s):  
Endothelial Cells ◽  
Receptor Agonist ◽  
Umbilical Vein ◽  
Thrombin Receptor ◽  
Agonist Peptide ◽  
Human Umbilical Vein ◽  
Umbilical Vein Endothelial Cells

The functional thrombin receptor is associated with the plasmalemma and a large endosomal network in cultured human umbilical vein endothelial cells

1995 ◽  
Vol 108 (3) ◽  
pp. 1155-1164 ◽  
Author(s):  
R. Horvat ◽  
G.E. Palade
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Morphological Evidence ◽  
Thrombin Receptor ◽  
Human Umbilical Vein ◽  
Cultured Endothelial Cells ◽  
Human Thrombin ◽  
Membrane Spanning ◽  
Umbilical Vein Endothelial Cells ◽  
G Protein Coupled

The functional thrombin receptor, normally expressed by endothelial cells and platelets, is a member of the G protein-coupled, seven membrane-spanning-domain receptor family and is thought to be responsible for most, if not all, the cell stimulatory effects of thrombin. Upon binding, thrombin cleaves the receptor's N-terminal ectodomain, unmasking a new N terminus, which by itself activates the receptor. Using antibodies to different domains of the human thrombin receptor, we have localized the receptor in cultured human umbilical vein endothelial cells by indirect immunofluorescence and immunoelectron microscopy. We found the receptor expressed on the plasmalemma of cultured endothelial cells in individual units rather than in clusters, at lower concentration than, and at different sites from, thrombomodulin. We also found the receptor associated with a distinct, intracellular, transferrin receptor-containing, tubulovesicular network. The thrombin receptor-positive structure spread from the perinuclear region to the periphery of the cells, exhibiting a number of varicosities interconnected by branching tubular elements, strikingly similar to an image recently described for a continuous endosomal reticulum. Our results provide morphological evidence for the presence of the functional thrombin receptor at relative low density on the surface of cultured endothelial cells (compared to thrombomodulin) and in relatively large quantities inside the cells, associated with an endosomal compartment.

Thrombomodulin Modulates the Mitogenic Response to Thrombin of Human Umbilical Vein Endothelial Cells

1998 ◽  
Vol 79 (04) ◽  
pp. 848-852 ◽  
Author(s):  
Monique Lafay ◽  
Reyes Laguna ◽  
Bernard Le Bonniec ◽  
Dominique Lasne ◽  
Martine Aiach ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Umbilical Vein ◽  
Thrombin Receptor ◽  
Mitogenic Response ◽  
Human Umbilical Vein ◽  
Umbilical Vein Endothelial Cells ◽  
Huvec Proliferation

SummaryThrombin interacts with its receptor and thrombomodulin on endothelial cells. We evaluated the respective roles of these two proteins on human umbilical vein endothelial cell (HUVEC) growth by comparing thrombin, S195A (a mutant thrombin in which the serine of the charge stabilizing system had been replaced by alanine), and the receptor activating peptide (TRAP). Thrombin and TRAP induced DNA synthesis (half maximal cell proliferation with 5 nM and 25 μM, respectively), whereas S195A thrombin was inactive, inferring that growth is mediated through the thrombin receptor. Surprisingly, cells stimulated by TRAP exhibited a maximal proliferation twice greater than that obtained with thrombin. Combination of thrombin and TRAP resulted in a mitogenic response higher than by thrombin alone, but lower than by TRAP alone. The role of thrombomodulin was evaluated by adding an anti-thrombomodulin antibody, which prevents formation of the thrombin-thrombomodulin complex. Antibody did not interfere with cell proliferation induced by TRAP, but enhanced that induced by thrombin. We conclude that formation of the thrombin-thrombomodulin complex restrains HUVEC proliferation mediated through the thrombin receptor.

Studies of the Factor Xa-Dependent Inhibitor of Factor VIIa/Tissue Factor (Extrinsic Pathway Inhibitor) from Cell Supernates of Cultured Human Umbilical Vein Endothelial Cells

1989 ◽  
Vol 61 (01) ◽  
pp. 101-105 ◽  
Author(s):  
Bonnie J Warn-Cramer ◽  
Fanny E Almus ◽  
Samuel I Rapaport
Keyword(s):  
Molecular Weight ◽  
Endothelial Cells ◽  
Tissue Factor ◽  
Phorbol Ester ◽  
Umbilical Vein ◽  
Primary Cultures ◽  
Factor Xa ◽  
Extrinsic Pathway ◽  
Human Umbilical Vein ◽  
Umbilical Vein Endothelial Cells

SummaryCultured human umbilical vein endothelial cells (HUVEC) have been reported to produce extrinsic pathway inhibitor (EPI), the factor Xa-dependent inhibitor of factor VHa/tissue factor (TF). We examined the release of this inhibitor from HUVEC as a function of their growth state and in response to the induction of endothelial cell TF activity. HUVEC constitutively produced significant amounts of EPI at all stages of their growth in culture including the post-confluent state. Rate of release varied over a 3-fold range for primary cultures from 12 different batches of pooled umbilical cord cells. Constitutive EPI release was unaltered during a 6 hour period of induction of TF activity with thrombin or phorbol ester but slowed during longer incubation of the cells with phorbol ester. Whereas plasma contains two molecular weight forms of EPI, only the higher of these two molecular weight forms was demonstrable by Western analysis of HUVEC supernatants with 125I-factor Xa as the ligand.

Partial Characterization of a Fibrinolytic Inhibitor Produced by Cultured Endothelial Cells Derived from Human Umbilical Vein

1982 ◽  
Vol 47 (02) ◽  
pp. 128-131 ◽  
Author(s):  
F Esnard ◽  
E Dupuy ◽  
A M Dosne ◽  
E Bodevin
Keyword(s):  
Endothelial Cells ◽  
Primary Culture ◽  
Ammonium Sulphate ◽  
Concanavalin A ◽  
Umbilical Vein ◽  
Human Umbilical Vein ◽  
Preliminary Characterization ◽  
Umbilical Vein Endothelial Cells ◽  
Ammonium Sulphate Saturation

SummaryA preliminary characterization of a fibrinolytic inhibitor released by human umbilical vein endothelial cells in primary culture is reported. This molecule of Mr comprised between 2 × 105 and 106 and of μ2 mobility precipitates at 43% ammonium sulphate saturation and is totally adsorbed on Concanavalin A Sepharose 4 B. A possible relationship with a macroglobulins is discussed.

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