scholarly journals Cultured human endothelial cells synthesize a plasma membrane protein complex immunologically related to the platelet glycoprotein IIb/IIIa complex

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 1176-1180 ◽  
Author(s):  
OC Leeksma ◽  
J Zandbergen-Spaargaren ◽  
JC Giltay ◽  
JA van Mourik

Abstract We have previously demonstrated that endothelial cells synthesize a plasma membrane protein indistinguishable from platelet glycoprotein (GP) IIa. The present study provides evidence for a further analogy between the platelet and the endothelial cell membrane by showing that cultured endothelial cells also synthesize a membrane protein complex immunologically related to the platelet GP IIb/GP IIIa complex. This evidence is based on the following observations: (1) C17, a murine monoclonal antiplatelet GP IIIa antibody, consistently precipitates two proteins, apparent molecular weights, respectively, 115,000 and 125,000 reduced and 95,000 and 135,000 nonreduced, from metabolically (35S- methionine) as well as surface 125I-labeled cultured human endothelial cells; (2) upon crossed immunoelectrophoresis of solubilized endothelial cells against a polyclonal rabbit antiplatelet antiserum and 125I-labeled C17 IgG, a single precipitate of the protein(s) recognized by C17 is observed. As judged by their mobility in 9% polyacrylamide gels, both endothelial proteins appear to have a somewhat larger molecular weight than their platelet counterparts. Patterns obtained by crossed immunoelectrophoresis are also indicative of a difference in electrophoretic behavior of the platelet GP IIb/IIIa complex and the endothelial cell protein complex.

Blood ◽  
1986 ◽  
Vol 67 (4) ◽  
pp. 1176-1180
Author(s):  
OC Leeksma ◽  
J Zandbergen-Spaargaren ◽  
JC Giltay ◽  
JA van Mourik

We have previously demonstrated that endothelial cells synthesize a plasma membrane protein indistinguishable from platelet glycoprotein (GP) IIa. The present study provides evidence for a further analogy between the platelet and the endothelial cell membrane by showing that cultured endothelial cells also synthesize a membrane protein complex immunologically related to the platelet GP IIb/GP IIIa complex. This evidence is based on the following observations: (1) C17, a murine monoclonal antiplatelet GP IIIa antibody, consistently precipitates two proteins, apparent molecular weights, respectively, 115,000 and 125,000 reduced and 95,000 and 135,000 nonreduced, from metabolically (35S- methionine) as well as surface 125I-labeled cultured human endothelial cells; (2) upon crossed immunoelectrophoresis of solubilized endothelial cells against a polyclonal rabbit antiplatelet antiserum and 125I-labeled C17 IgG, a single precipitate of the protein(s) recognized by C17 is observed. As judged by their mobility in 9% polyacrylamide gels, both endothelial proteins appear to have a somewhat larger molecular weight than their platelet counterparts. Patterns obtained by crossed immunoelectrophoresis are also indicative of a difference in electrophoretic behavior of the platelet GP IIb/IIIa complex and the endothelial cell protein complex.


1990 ◽  
Vol 63 (02) ◽  
pp. 303-311
Author(s):  
Tone Børsum

SummaryHuman endothelial cells isolated from umbilical cordswere solubilized in Triton X-100 and examined by crossedimmunoelec-trophoresis using rabbit antiserum against endothelial cells. Endogenous labelling of the endothelialcell proteins with 14Cmannose followed by crossed immunoelectrophoresis and autoradiography revealed about 10 immunoprecipitates. Four of these endothelial cell glycoproteins were labelled by lactoperoxidase catalyzed iodination and thus were surface located. Three of the surface located glycoproteins showed reduced electrophoretic mobility after incubation of the endothelial cells with neuraminidase and were therefore sialoglycoproteins. Amphiphilicity of endothelial cell glycoproteins was studied by crossed hydrophobic interaction immunoelectrophoresis with phenyl-Sepharose in the intermediate gel. Amphiphilic proteins also show increasing electrophoretic migration velocity with decreasing concentration of Triton X-100 in the first dimension gels. Five of the endothelial cell glycoproteins were shown to be amphiphilic using these two techniques.Two monoclonal antibodies against the platelet glycoprotein complex Ilb-IIIa and glycoprotein IlIa, respectively, reacted with the same precipitate of endothelial cells. When a polyclonal antibody against the platelet glycoprotein complex Ilb-IIIa was incorporated into the intermediate gel the position of two endothelial cell precipitates were lowered. One of these was a sialoglycoprotein.


Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 809-812 ◽  
Author(s):  
JC Giltay ◽  
OC Leeksma ◽  
C Breederveld ◽  
JA van Mourik

Abstract Glanzmann's thrombasthenia is a bleeding disorder, inherited in an autosomal recessive way and characterized by an absence or deficiency of the platelet glycoprotein (GP) IIb/IIIa complex. Recently, we and others demonstrated that cultured human umbilical vein endothelial cells synthesized a membrane protein complex similar to the platelet GP IIb/IIIa complex. In this article, we demonstrate that endothelial cells isolated from the umbilical vein of a newborn with Glanzmann's thrombasthenia, as compared with normal endothelial cells, show no difference in their ability to synthesize and express this GP IIb/IIIa complex. Our results indicate that Glanzmann's thrombasthenia is not accompanied by an “endotheliopathy.”


Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 809-812
Author(s):  
JC Giltay ◽  
OC Leeksma ◽  
C Breederveld ◽  
JA van Mourik

Glanzmann's thrombasthenia is a bleeding disorder, inherited in an autosomal recessive way and characterized by an absence or deficiency of the platelet glycoprotein (GP) IIb/IIIa complex. Recently, we and others demonstrated that cultured human umbilical vein endothelial cells synthesized a membrane protein complex similar to the platelet GP IIb/IIIa complex. In this article, we demonstrate that endothelial cells isolated from the umbilical vein of a newborn with Glanzmann's thrombasthenia, as compared with normal endothelial cells, show no difference in their ability to synthesize and express this GP IIb/IIIa complex. Our results indicate that Glanzmann's thrombasthenia is not accompanied by an “endotheliopathy.”


Author(s):  
J C Giltay ◽  
O C Leeksma ◽  
A E G Kr v d Borne ◽  
J A van Mourik

Zwa (P1A1) is a platelet specific alloantigen, located on glycoprotein (GP) IIIa, and is of pathogenic importance in alloimmunologic disorders such as neonatal alloimmune thrombocytopenia and post transfusion purpura. As endothelial cells synthesize a plasma membrane protein complex which is structurally closely related to the platelet membrane GP IIb/IIIa complex, we examined whether these cells also express Zwa. Employing a variety of immunochemical techniques, our studies show that endothelial cells indeed can express this antigen at the plasma membrane surface.We also compared the expression of Zwa on platelets, isolated from umbilical cord blood, with the expression of Zwa on cultured endothelial cells, isolated from the same umbilical cord, of a number of neonates. Both platelets and endothelial cells obtained from the same individual, either expressed Zwa (Zwa positive individuals) or lacked expression of Zwa (Zwa negative individuals). These findings strongly suggest that endothelial-and platelet Zwa are encoded by the same genes.Thus, Zwa is not exclusively expressed by platelets, also endothelial cells express this alloantigen.An important consequence could be, that in alloimmunologic disorders in which the Zwa antigen is implicated, not only the platelets, but also the vessel wall is involved.


1981 ◽  
Vol 46 (02) ◽  
pp. 504-506 ◽  
Author(s):  
T K Chan ◽  
Vivian Chan

SummaryHuman endothelial cells in culture is shown to synthesize antithrombin III (At-III). The endothelial cell At-III(EC-At-III) consists of a small fraction similar to plasma At-III and a larger fraction with decreased heparin-binding as tested by crossed immunoelectrophoresis. However, both the anti-Xa and thrombin-neutralizing activities of the EC-At-III were rapid and active even in the absence of added heparin. It is concluded that the major portion was probably bound to endogenous heparin-like substance, thus accounting for its decreased exogenous heparin binding. The presence of At-III and other antithrombotic factors in the vascular endothelium offer protection against thrombosis and possibly atherosclerosis.


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