Protein C supports platelet binding and activation under flow: Role of glycoprotein Ib and apolipoprotein E receptor 2

T. C. White, M. A. Berny, Erik Tucker, R. T. Urbanus, P. G. De Groot, J. A. Fernández, J. H. Griffin, Andras Gruber, Owen McCarty

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Background: Activated protein C (APC) regulates thrombin generation and inhibits apoptosis. Endothelial protein C receptor (EPCR)-bound protein C is activated by thrombomodulin-bound thrombin. APC inactivates coagulation factors (F)Va/VIIIa and generates cytoprotective signaling downstream of protease-activated receptor-1 (PAR-1). Binding of APC to EPCR both modifies and induces PAR-1 signaling, but it is unknown if protein C interacts with cells in an alternative manner. Aim: To determine whether platelets possess receptors for protein C that can generate intracellular signals. Results: Immobilized protein C or APC supported platelet adhesion, lamellipodia formation and elevation of intracellular Ca2+. Adhesion of platelets to protein C or APC was inhibited by soluble recombinant apolipoprotein E receptor 2′(ApoER2′) and by receptor-associated protein (RAP), an inhibitor of the low-density lipoprotein receptor family. Under shear, surface-bound protein C supported platelet adhesion and aggregation in a glycoprotein (GP)Ibα-dependent manner, and adhesion of platelets to immobilized protein C was abrogated by the addition of soluble forms of ApoER2′ or RAP. APC bound to purified recombinant ApoER2′ or GPIbα. Conclusions: Our data demonstrate that activation of platelets with rapid intracellular signaling caused by binding to immobilized protein C or APC occurs via mechanisms that require ApoER2 and GPIbα and that APC directly binds to purified ectodomains of the receptors ApoER2 and GPIbα. These findings imply that protein C and APC may directly promote cell signaling in other cells by binding to ApoER2 and/or GPIbα.

Original languageEnglish (US)
Pages (from-to)995-1002
Number of pages8
JournalJournal of Thrombosis and Haemostasis
Volume6
Issue number6
DOIs
StatePublished - Jun 2008

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Platelet Glycoprotein GPIb-IX Complex
Platelet Activation
Protein C
Immobilized Proteins
Blood Platelets
low density lipoprotein receptor-related protein 8
PAR-1 Receptor
Thrombin
Factor Va

Keywords

  • Activated protein C
  • Apolipoprotein E receptor 2
  • Glycoprotein Ib
  • Platelet activation

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Protein C supports platelet binding and activation under flow : Role of glycoprotein Ib and apolipoprotein E receptor 2. / White, T. C.; Berny, M. A.; Tucker, Erik; Urbanus, R. T.; De Groot, P. G.; Fernández, J. A.; Griffin, J. H.; Gruber, Andras; McCarty, Owen.

In: Journal of Thrombosis and Haemostasis, Vol. 6, No. 6, 06.2008, p. 995-1002.

Research output: Contribution to journalArticle

White, T. C. ; Berny, M. A. ; Tucker, Erik ; Urbanus, R. T. ; De Groot, P. G. ; Fernández, J. A. ; Griffin, J. H. ; Gruber, Andras ; McCarty, Owen. / Protein C supports platelet binding and activation under flow : Role of glycoprotein Ib and apolipoprotein E receptor 2. In: Journal of Thrombosis and Haemostasis. 2008 ; Vol. 6, No. 6. pp. 995-1002.
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abstract = "Background: Activated protein C (APC) regulates thrombin generation and inhibits apoptosis. Endothelial protein C receptor (EPCR)-bound protein C is activated by thrombomodulin-bound thrombin. APC inactivates coagulation factors (F)Va/VIIIa and generates cytoprotective signaling downstream of protease-activated receptor-1 (PAR-1). Binding of APC to EPCR both modifies and induces PAR-1 signaling, but it is unknown if protein C interacts with cells in an alternative manner. Aim: To determine whether platelets possess receptors for protein C that can generate intracellular signals. Results: Immobilized protein C or APC supported platelet adhesion, lamellipodia formation and elevation of intracellular Ca2+. Adhesion of platelets to protein C or APC was inhibited by soluble recombinant apolipoprotein E receptor 2′(ApoER2′) and by receptor-associated protein (RAP), an inhibitor of the low-density lipoprotein receptor family. Under shear, surface-bound protein C supported platelet adhesion and aggregation in a glycoprotein (GP)Ibα-dependent manner, and adhesion of platelets to immobilized protein C was abrogated by the addition of soluble forms of ApoER2′ or RAP. APC bound to purified recombinant ApoER2′ or GPIbα. Conclusions: Our data demonstrate that activation of platelets with rapid intracellular signaling caused by binding to immobilized protein C or APC occurs via mechanisms that require ApoER2 and GPIbα and that APC directly binds to purified ectodomains of the receptors ApoER2 and GPIbα. These findings imply that protein C and APC may directly promote cell signaling in other cells by binding to ApoER2 and/or GPIbα.",
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T2 - Role of glycoprotein Ib and apolipoprotein E receptor 2

AU - White, T. C.

AU - Berny, M. A.

AU - Tucker, Erik

AU - Urbanus, R. T.

AU - De Groot, P. G.

AU - Fernández, J. A.

AU - Griffin, J. H.

AU - Gruber, Andras

AU - McCarty, Owen

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N2 - Background: Activated protein C (APC) regulates thrombin generation and inhibits apoptosis. Endothelial protein C receptor (EPCR)-bound protein C is activated by thrombomodulin-bound thrombin. APC inactivates coagulation factors (F)Va/VIIIa and generates cytoprotective signaling downstream of protease-activated receptor-1 (PAR-1). Binding of APC to EPCR both modifies and induces PAR-1 signaling, but it is unknown if protein C interacts with cells in an alternative manner. Aim: To determine whether platelets possess receptors for protein C that can generate intracellular signals. Results: Immobilized protein C or APC supported platelet adhesion, lamellipodia formation and elevation of intracellular Ca2+. Adhesion of platelets to protein C or APC was inhibited by soluble recombinant apolipoprotein E receptor 2′(ApoER2′) and by receptor-associated protein (RAP), an inhibitor of the low-density lipoprotein receptor family. Under shear, surface-bound protein C supported platelet adhesion and aggregation in a glycoprotein (GP)Ibα-dependent manner, and adhesion of platelets to immobilized protein C was abrogated by the addition of soluble forms of ApoER2′ or RAP. APC bound to purified recombinant ApoER2′ or GPIbα. Conclusions: Our data demonstrate that activation of platelets with rapid intracellular signaling caused by binding to immobilized protein C or APC occurs via mechanisms that require ApoER2 and GPIbα and that APC directly binds to purified ectodomains of the receptors ApoER2 and GPIbα. These findings imply that protein C and APC may directly promote cell signaling in other cells by binding to ApoER2 and/or GPIbα.

AB - Background: Activated protein C (APC) regulates thrombin generation and inhibits apoptosis. Endothelial protein C receptor (EPCR)-bound protein C is activated by thrombomodulin-bound thrombin. APC inactivates coagulation factors (F)Va/VIIIa and generates cytoprotective signaling downstream of protease-activated receptor-1 (PAR-1). Binding of APC to EPCR both modifies and induces PAR-1 signaling, but it is unknown if protein C interacts with cells in an alternative manner. Aim: To determine whether platelets possess receptors for protein C that can generate intracellular signals. Results: Immobilized protein C or APC supported platelet adhesion, lamellipodia formation and elevation of intracellular Ca2+. Adhesion of platelets to protein C or APC was inhibited by soluble recombinant apolipoprotein E receptor 2′(ApoER2′) and by receptor-associated protein (RAP), an inhibitor of the low-density lipoprotein receptor family. Under shear, surface-bound protein C supported platelet adhesion and aggregation in a glycoprotein (GP)Ibα-dependent manner, and adhesion of platelets to immobilized protein C was abrogated by the addition of soluble forms of ApoER2′ or RAP. APC bound to purified recombinant ApoER2′ or GPIbα. Conclusions: Our data demonstrate that activation of platelets with rapid intracellular signaling caused by binding to immobilized protein C or APC occurs via mechanisms that require ApoER2 and GPIbα and that APC directly binds to purified ectodomains of the receptors ApoER2 and GPIbα. These findings imply that protein C and APC may directly promote cell signaling in other cells by binding to ApoER2 and/or GPIbα.

KW - Activated protein C

KW - Apolipoprotein E receptor 2

KW - Glycoprotein Ib

KW - Platelet activation

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