Binding of heparin to plasma proteins and endothelial surfaces is inhibited by covalent linkage to antithrombin

2004 ◽  
Vol 91 (05) ◽  
pp. 1009-1018 ◽  
Author(s):  
Nethnapha Paredes ◽  
Bruce Thong ◽  
Paul Chindemi ◽  
Bosco Paes ◽  
Leslie Berry ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Surface ◽  
Half Life ◽  
Plasma Proteins ◽  
Anticoagulant Activity ◽  
Surface Proteins ◽  
Coagulation Cascade ◽  
Covalent Linkage ◽  
Endothelial Cell Surface

SummaryUnfractionated heparin (UFH) and low molecular weight heparin (LMWH) are used for prophylaxis and treatment of thrombosis. However, UFH has a short plasma half-life and variable anticoagulant response in vivo due to plasma or vessel wall protein binding and LMWH has a decreased ability to inactivate thrombin, the pivotal enzyme in the coagulation cascade. Covalent linkage of antithrombin to heparin gave a complex (ATH) with superior anticoagulant activity compared to UFH and LMWH, and longer intravenous half-life compared to UFH. We found that plasma proteins bound more to UFH than ATH, and least to LMWH. Also, UFH bound significantly more to endothelial cells than ATH, with 100% of UFH and 94% of ATH binding being on the cell surface and the remainder was endocytosed. Competition studies with UFH confirmed that ATH binding was likely through its heparin moiety. These findings suggest that differences in plasma protein and endothelial cell binding may be due to available heparin chain length. Although ATH is polydisperse, the covalently-linked antithrombin may shield a portion of the heparin chain from association with plasma or endothelial cell surface proteins. This model is consistent with ATH’s better bioavailability and more predictable dose response.

scholarly journals Surface charge distribution on the endothelial cell of liver sinusoids.

1984 ◽  
Vol 99 (2) ◽  
pp. 639-647 ◽  
Author(s):  
L Ghitescu ◽  
A Fixman
Keyword(s):  
Endothelial Cell ◽  
Cell Surface ◽  
Liver Sinusoid ◽  
Electron Microscopic ◽  
Coated Pits ◽  
Endothelial Cell Surface ◽  
Liver Sinusoids ◽  
Surface Charge Distribution ◽  
Cationic Residues

The topography of the charged residues on the endothelial cell surface of liver sinusoid capillaries was investigated by using electron microscopic tracers of different size and charge. The tracers used were native ferritin (pl 4.2-4.7) and its cationized (pl 8.4) and anionized (pl 3.7) derivatives, BSA coupled to colloidal gold (pl of the complex 5.1), hemeundecapeptide (pl 4.85), and alcian blue (pl greater than 10). The tracers were either injected in vivo or perfused in situ through the portal vein of the mouse liver. In some experiments, two tracers of opposite charge were sequentially perfused with extensive washing in between. The liver was processed for electron microscopy and the binding pattern of the injected markers was recorded. The electrostatic nature of the tracer binding was assessed by perfusion with high ionic strength solutions, by aldehyde quenching of the plasma membrane basic residues, and by substituting the cell surface acidic moieties with positively charged groups. Results indicate that the endothelial cells of the liver sinusoids expose on their surface both cationic and anionic residues. The density distribution of these charged groups on the cell surface is different. While the negative charge is randomly and patchily scattered all over the membrane, the cationic residues seem to be accumulated in coated pits. The charged groups co-exist in the same coated pit and bind the opposite charged macromolecule. It appears that the fixed positive and negative charges of the coated pit glycocalyx are mainly segregated in space. The layer of basic residues is located at 20-30-nm distance of the membrane, while most of the negative charges lie close to the external leaflet of the plasmalemma.

scholarly journals Histidine-rich glycoprotein does not interfere with interactions between antithrombin III and heparin-like compounds on vascular endothelial cells

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 191-193 ◽  
Author(s):  
K Shimada ◽  
A Kawamoto ◽  
K Matsubayashi ◽  
T Ozawa
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Antithrombin Iii ◽  
Vascular Endothelial Cells ◽  
Anticoagulant Activity ◽  
Molar Ratio ◽  
Vascular Endothelial ◽  
Aortic Endothelial Cells ◽  
Endothelial Cell Surface

Abstract The role of histidine-rich glycoprotein in controlling heparin-like compounds on the endothelial cell surface is still unclear. The effects of this heparin-neutralizing protein on the interaction between antithrombin III and cultured porcine aortic endothelial cells were examined. Displacement of 125I-labeled antithrombin III specifically bound to endothelial cells by unlabeled histidine-rich glycoprotein was much less potent than that by unlabeled antithrombin III. One hundred- fold molar excess of histidine-rich glycoprotein displaced specific 125I-antithrombin III binding only by 20%. Furthermore, the endothelial cell-mediated acceleration of thrombin inactivation by antithrombin III was diminished by protamine sulfate, but was not affected by histidine- rich glycoprotein even at a histidine-rich glycoprotein/antithrombin III molar ratio of approximately 7:1. These data indicate that histidine-rich glycoprotein does not interfere with the interaction of endothelial cell heparin-like compounds with antithrombin III. Thus, it may not play an important role in the modulation of anticoagulant activity of endothelial cells in vivo, suggesting that the commonly accepted view of the probable function of this protein is erroneous.

Identification of a Binding Partner for the Endothelial Cell Surface Proteins TEM7 and TEM7R

2004 ◽  
Vol 64 (23) ◽  
pp. 8507-8511 ◽  
Author(s):  
Akash Nanda ◽  
Phillip Buckhaults ◽  
Steven Seaman ◽  
Nishant Agrawal ◽  
Paula Boutin ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Surface ◽  
Surface Proteins ◽  
Cell Surface Proteins ◽  
Binding Partner ◽  
Endothelial Cell Surface

scholarly journals Histidine-rich glycoprotein does not interfere with interactions between antithrombin III and heparin-like compounds on vascular endothelial cells

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 191-193
Author(s):  
K Shimada ◽  
A Kawamoto ◽  
K Matsubayashi ◽  
T Ozawa
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Antithrombin Iii ◽  
Vascular Endothelial Cells ◽  
Anticoagulant Activity ◽  
Molar Ratio ◽  
Vascular Endothelial ◽  
Aortic Endothelial Cells ◽  
Endothelial Cell Surface

The role of histidine-rich glycoprotein in controlling heparin-like compounds on the endothelial cell surface is still unclear. The effects of this heparin-neutralizing protein on the interaction between antithrombin III and cultured porcine aortic endothelial cells were examined. Displacement of 125I-labeled antithrombin III specifically bound to endothelial cells by unlabeled histidine-rich glycoprotein was much less potent than that by unlabeled antithrombin III. One hundred- fold molar excess of histidine-rich glycoprotein displaced specific 125I-antithrombin III binding only by 20%. Furthermore, the endothelial cell-mediated acceleration of thrombin inactivation by antithrombin III was diminished by protamine sulfate, but was not affected by histidine- rich glycoprotein even at a histidine-rich glycoprotein/antithrombin III molar ratio of approximately 7:1. These data indicate that histidine-rich glycoprotein does not interfere with the interaction of endothelial cell heparin-like compounds with antithrombin III. Thus, it may not play an important role in the modulation of anticoagulant activity of endothelial cells in vivo, suggesting that the commonly accepted view of the probable function of this protein is erroneous.

scholarly journals Thymidine phosphorylase, 2-deoxy-D-ribose and angiogenesis

1998 ◽  
Vol 334 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Nicholas S. BROWN ◽  
Roy BICKNELL
Keyword(s):  
Endothelial Cell ◽  
Cell Surface ◽  
Thymidine Phosphorylase ◽  
Endothelial Cell Migration ◽  
Cell Surface Receptor ◽  
Migratory Activity ◽  
Surface Receptors ◽  
Endothelial Cell Surface ◽  
Mechanistic Pathway

Angiogenesis is the term used to describe the formation of new blood vessels from the existing vasculature. In order to attract new vessels, a tissue must release an endothelial-cell chemoattractant. 2-Deoxy-d-ribose is produced in vivo by the catalytic action of thymidine phosphorylase (TP) on thymidine and has recently been identified as an endothelial-cell chemoattractant and angiogenesis-inducing factor. TP, previously known only for its role in nucleotide salvage, is now known to be angiogenic. TP expression is elevated in many solid tumours and in chronically inflamed tissues, both known areas of active angiogenesis. There is evidence that TP is also involved in physiological angiogenesis such as endometrial angiogenesis during the menstrual cycle. The majority of known endothelial-cell chemoattractants are polypeptides that bind to endothelial-cell-surface receptors. In contrast, 2-deoxy-d-ribose appears to lack a cell-surface receptor. Glucose is another sugar that acts as an endothelial-cell chemoattractant. The migratory activity of glucose is blocked by ouabain. It is possible that 2-deoxy-d-ribose and glucose stimulate endothelial-cell migration via a similar mechanistic pathway.

Effect of hypercarbia on surface proteins of cultured bovine endothelial cells

1997 ◽  
Vol 273 (6) ◽  
pp. L1141-L1146 ◽  
Author(s):  
Sharon Rounds ◽  
Damani Piggott ◽  
Doloretta D. Dawicki ◽  
Harrison W. Farber
Keyword(s):  
Endothelial Cell ◽  
Cell Surface ◽  
Pulmonary Artery ◽  
Main Pulmonary Artery ◽  
Surface Proteins ◽  
Western Blots ◽  
Cell Surface Proteins ◽  
Apical Cell Membrane ◽  
Endothelial Cell Surface ◽  
Pulmonary Artery Endothelial Cell

Hypercarbia is a common complication of respiratory failure, and the technique of “permissive hypercapnia” is used to ventilate individuals with increased peak airway pressures on mechanical ventilators, resulting in elevated arterial [Formula: see text]. We studied the effects of hypercarbia on cultured bovine aortic and main pulmonary artery endothelial cell surface proteins, assessing cell surface iodination using lactoperoxidase bound to latex microspheres. We found that 4 h of exposure to 10% CO2increased the display of substances of apparent molecular masses of 27, 47, and 52 kDa. This effect was not mimicked by acidotic media. Western blots of detergent extracts of main pulmonary artery endothelial cell monolayers did not show increased expression of carbonic anhydrase IV (molecular mass = 52 kDa) after incubation under hypercarbic conditions. Hypercarbia did not change the pattern of [35S]methionine incorporation into endothelial cell proteins. We conclude that hypercarbia of 4-h duration changes iodinated endothelial cell surface proteins. We speculate that this effect may be related to changes in secretion or display of apical cell membrane-associated proteins.

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