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Constantinescu-Bercu A, Wang YA, Woollard KJ, Mangin P, Vanhoorelbeke K, Crawley JTB, Salles-Crawley II. The GPIbα intracellular tail - role in transducing VWF- and collagen/GPVI-mediated signaling. Haematologica 2022; 107:933-946. [PMID: 34134470 PMCID: PMC8968903 DOI: 10.3324/haematol.2020.278242] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Indexed: 11/09/2022] Open
Abstract
The GPIbT-VWF A1 domain interaction is essential for platelet tethering under high shear. Synergy between GPIbα and GPVI signaling machineries has been suggested previously, however its molecular mechanism remains unclear. We generated a novel GPIbα transgenic mouse (GpIbαΔsig/Δsig) by CRISPR-Cas9 technology to delete the last 24 residues of the GPIbα intracellular tail that harbors the 14-3-3 and phosphoinositide-3 kinase binding sites. GPIbαΔsig/Δsig platelets bound VWF normally under flow. However, they formed fewer filopodia on VWF/botrocetin in the presence of a oIIbI3 blocker, demonstrating that despite normal ligand binding, VWF-dependent signaling is diminished. Activation of GpIbαΔsig/Δsig platelets with ADP and thrombin was normal, but GpIbαΔsig/Δsig platelets stimulated with collagen-related-peptide (CRP) exhibited markedly decreased P-selectin exposure and eIIbI3 activation, suggesting a role for the GpIbaaintracellular tail in GPVI-mediated signaling. Consistent with this, while haemostasis was normal in GPIbαΔsig/Δsig mice, diminished tyrosine-phosphorylation, (particularly pSYK) was detected in CRP-stimulated GpIbαΔsig/Δsig platelets as well as reduced platelet spreading on CRP. Platelet responses to rhodocytin were also affected in GpIbαΔsig/Δsig platelets but to a lesser extent than those with CRP. GpIbαΔsig/Δsig platelets formed smaller aggregates than wild-type platelets on collagen-coated microchannels at low, medium and high shear. In response to both VWF and collagen binding, flow assays performed with plasma-free blood or in the presence of bIIbI3- or GPVI-blockers suggested reduced bIIbI3 activation contributes to the phenotype of the GpIbαΔsig/Δsig platelets. Together, these results reveal a new role for the intracellular tail of GPIbiiin transducing both VWF-GPIbGGand collagen-GPVI signaling events in platelets.
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Affiliation(s)
| | - Yuxiao A Wang
- Centre for Haematology, Department of Immunology and Inflammation, Imperial College London, London, UK
| | - Kevin J Woollard
- Centre for Inflammatory Disease, Department of Immunology and Inflammation, Imperial College London, London, UK
| | - Pierre Mangin
- Université de Strasbourg, INSERM, EFS Grand-Est, BPPS UMR-S 1255, FMTS, Strasbourg, France
| | | | - James T B Crawley
- Centre for Haematology, Department of Immunology and Inflammation, Imperial College London, London, UK
| | - Isabelle I Salles-Crawley
- Centre for Haematology, Department of Immunology and Inflammation, Imperial College London, London, UK.
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A Novel Mutation in GP1BB Reveals the Role of the Cytoplasmic Domain of GPIbβ in the Pathophysiology of Bernard-Soulier Syndrome and GPIb-IX Complex Assembly. Int J Mol Sci 2021; 22:ijms221910190. [PMID: 34638529 PMCID: PMC8508601 DOI: 10.3390/ijms221910190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 12/24/2022] Open
Abstract
Bernard-Soulier syndrome (BSS) is an autosomal-recessive bleeding disorder caused by biallelic variants in the GP1BA, GP1BB, and GP9 genes encoding the subunits GPIbα, GPIbβ, and GPIX of the GPIb-IX complex. Pathogenic variants usually affect the extracellular or transmembrane domains of the receptor subunits. We investigated a family with BSS caused by the homozygous c.528_550del (p.Arg177Serfs*124) variant in GP1BB, which is the first mutation ever identified that affects the cytoplasmic domain of GPIbβ. The loss of the intracytoplasmic tail of GPIbβ results in a mild form of BSS, characterized by only a moderate reduction of the GPIb-IX complex expression and mild or absent bleeding tendency. The variant induces a decrease of the total platelet expression of GPIbβ; however, all of the mutant subunit expressed in platelets is correctly assembled into the GPIb-IX complex in the plasma membrane, indicating that the cytoplasmic domain of GPIbβ is not involved in assembly and trafficking of the GPIb-IX receptor. Finally, the c.528_550del mutation exerts a dominant effect and causes mild macrothrombocytopenia in heterozygous individuals, as also demonstrated by the investigation of a second unrelated pedigree. The study of this novel GP1BB variant provides new information on pathophysiology of BSS and the assembly mechanisms of the GPIb-IX receptor.
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Makhoul S, Trabold K, Gambaryan S, Tenzer S, Pillitteri D, Walter U, Jurk K. cAMP- and cGMP-elevating agents inhibit GPIbα-mediated aggregation but not GPIbα-stimulated Syk activation in human platelets. Cell Commun Signal 2019; 17:122. [PMID: 31519182 PMCID: PMC6743169 DOI: 10.1186/s12964-019-0428-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 08/29/2019] [Indexed: 12/29/2022] Open
Abstract
Background The glycoprotein (GP) Ib-IX-V complex is a unique platelet plasma membrane receptor, which is essential for platelet adhesion and thrombus formation. GPIbα, part of the GPIb-IX-V complex, has several physiological ligands such as von Willebrand factor (vWF), thrombospondin and distinct coagulation factors, which trigger platelet activation. Despite having an important role, intracellular GPIb-IX-V signaling and its regulation by other pathways are not well defined. Our aim was to establish the intracellular signaling response of selective GPIbα activation in human platelets, in particular the role of the tyrosine kinase Syk and its regulation by cAMP/PKA and cGMP/PKG pathways, respectively. We addressed this using echicetin beads (EB), which selectively bind to GPIbα and induce platelet aggregation. Methods Purified echicetin from snake Echis carinatus venom was validated by mass spectrometry. Washed human platelets were incubated with EB, in the presence or absence of echicetin monomers (EM), Src family kinase (SFK) inhibitors, Syk inhibitors and the cAMP- and cGMP-elevating agents iloprost and riociguat, respectively. Platelet aggregation was analyzed by light transmission aggregometry, protein phosphorylation by immunoblotting. Intracellular messengers inositolmonophosphate (InsP1) and Ca2+i were measured by ELISA and Fluo-3 AM/FACS, respectively. Results EB-induced platelet aggregation was dependent on integrin αIIbβ3 and secondary mediators ADP and TxA2, and was antagonized by EM. EB stimulated Syk tyrosine phosphorylation at Y352, which was SFK-dependent and Syk-independent, whereas Y525/526 phosphorylation was SFK-dependent and partially Syk-dependent. Furthermore, phosphorylation of both Syk Y352 and Y525/526 was completely integrin αIIbβ3-independent but, in the case of Y525/526, was partially ADP/TxA2-dependent. Syk activation, observed as Y352/ Y525/Y526 phosphorylation, led to the phosphorylation of direct substrates (LAT Y191, PLCγ2 Y759) and additional targets (Akt S473). PKA/PKG pathways inhibited EB-induced platelet aggregation and Akt phosphorylation but, surprisingly, enhanced Syk and LAT/PLCγ2 tyrosine phosphorylation. A similar PKA/PKG effect was confirmed with convulxin−/GPVI-stimulated platelets. EB-induced InsP1 accumulation/InsP3 production and Ca2+-release were Syk-dependent, but only partially inhibited by PKA/PKG pathways. Conclusion EB and EM are specific agonists and antagonists, respectively, of GPIbα-mediated Syk activation leading to platelet aggregation. The cAMP/PKA and cGMP/PKG pathways do not inhibit but enhance GPIbα−/GPVI-initiated, SFK-dependent Syk activation, but strongly inhibit further downstream responses including aggregation. These data establish an important intracellular regulatory network induced by GPIbα. Graphical abstract ![]()
Electronic supplementary material The online version of this article (10.1186/s12964-019-0428-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephanie Makhoul
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Katharina Trabold
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stepan Gambaryan
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany.,Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Stefan Tenzer
- Core Facility for Mass Spectrometry, Institute for Immunology, University Medical Center Mainz, Mainz, Germany
| | | | - Ulrich Walter
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Kerstin Jurk
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany.
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Jiang Y, Fu H, Springer TA, Wong WP. Electrostatic Steering Enables Flow-Activated Von Willebrand Factor to Bind Platelet Glycoprotein, Revealed by Single-Molecule Stretching and Imaging. J Mol Biol 2019; 431:1380-1396. [PMID: 30797858 DOI: 10.1016/j.jmb.2019.02.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/21/2019] [Accepted: 02/14/2019] [Indexed: 01/13/2023]
Abstract
Von Willebrand factor (VWF), a large multimeric blood protein, senses changes in shear stress during bleeding and responds by binding platelets to plug ruptures in the vessel wall. Molecular mechanisms underlying this dynamic process are difficult to uncover using standard approaches due to the challenge of applying mechanical forces while monitoring structure and activity. By combining single-molecule fluorescence imaging with high-pressure, rapidly switching microfluidics, we reveal the key role of electrostatic steering in accelerating the binding between flow-activated VWF and GPIbα, and in rapidly immobilizing platelets under flow. We measure the elongation and tension-dependent activation of individual VWF multimers under a range of ionic strengths and pH levels, and find that the association rate is enhanced by 4 orders of magnitude by electrostatic steering. Under supraphysiologic salt concentrations, strong electrostatic screening dramatically decreases platelet binding to VWF in flow, revealing the critical role of electrostatic attraction in VWF-platelet binding during bleeding.
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Affiliation(s)
- Yan Jiang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Hongxia Fu
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Division of Hematology, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - Timothy A Springer
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
| | - Wesley P Wong
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA.
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Nygaard G, Herfindal L, Asrud KS, Bjørnstad R, Kopperud RK, Oveland E, Berven FS, Myhren L, Hoivik EA, Lunde THF, Bakke M, Døskeland SO, Selheim F. Epac1-deficient mice have bleeding phenotype and thrombocytes with decreased GPIbβ expression. Sci Rep 2017; 7:8725. [PMID: 28821815 PMCID: PMC5562764 DOI: 10.1038/s41598-017-08975-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 07/17/2017] [Indexed: 11/16/2022] Open
Abstract
Epac1 (Exchange protein directly activated by cAMP 1) limits fluid loss from the circulation by tightening the endothelial barrier. We show here that Epac1-/- mice, but not Epac2-/- mice, have prolonged bleeding time, suggesting that Epac1 may limit fluid loss also by restraining bleeding. The Epac1-/- mice had deficient in vitro secondary hemostasis. Quantitative comprehensive proteomics analysis revealed that Epac1-/- mouse platelets (thrombocytes) had unbalanced expression of key components of the glycoprotein Ib-IX-V (GPIb-IX-V) complex, with decrease of GP1bβ and no change of GP1bα. This complex is critical for platelet adhesion under arterial shear conditions. Furthermore, Epac1-/- mice have reduced levels of plasma coagulation factors and fibrinogen, increased size of circulating platelets, increased megakaryocytes (the GP1bβ level was decreased also in Epac1-/- bone marrow) and higher abundance of reticulated platelets. Viscoelastic measurement of clotting function revealed Epac1-/- mice with a dysfunction in the clotting process, which corresponds to reduced plasma levels of coagulation factors like factor XIII and fibrinogen. We propose that the observed platelet phenotype is due to deficient Epac1 activity during megakaryopoiesis and thrombopoiesis, and that the defects in blood clotting for Epac1-/- is connected to secondary hemostasis.
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Affiliation(s)
- Gyrid Nygaard
- Department of Biomedicine, University of Bergen, Bergen, Norway
- The Proteomics Unit at the University of Bergen, Bergen, Norway
| | - Lars Herfindal
- Centre for Pharmacy, Department of Clinical Science, University of Bergen, Bergen, Norway
| | | | - Ronja Bjørnstad
- Centre for Pharmacy, Department of Clinical Science, University of Bergen, Bergen, Norway
- Hospital Pharmacies Enterprise, Western Norway, Bergen, Norway
| | | | - Eystein Oveland
- The Proteomics Unit at the University of Bergen, Bergen, Norway
| | - Frode S Berven
- Department of Biomedicine, University of Bergen, Bergen, Norway
- The Proteomics Unit at the University of Bergen, Bergen, Norway
| | - Lene Myhren
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Erling A Hoivik
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Turid Helen Felli Lunde
- Department of Immunology and Transfusion Medicine, Haukeland University Hospital, Bergen, Norway
| | - Marit Bakke
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Frode Selheim
- Department of Biomedicine, University of Bergen, Bergen, Norway.
- The Proteomics Unit at the University of Bergen, Bergen, Norway.
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Li R, Emsley J. The organizing principle of the platelet glycoprotein Ib-IX-V complex. J Thromb Haemost 2013; 11:605-14. [PMID: 23336709 PMCID: PMC3696474 DOI: 10.1111/jth.12144] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 01/17/2013] [Indexed: 11/28/2022]
Abstract
The glycoprotein (GP)Ib-IX-V complex is the platelet receptor for von Willebrand factor and many other molecules that are critically involved in hemostasis and thrombosis. The lack of functional GPIb-IX-V complexes on the platelet surface is the cause of Bernard-Soulier syndrome, a rare hereditary bleeding disorder that is also associated with macrothrombocytopenia. GPIb-IX-V contains GPIbα, GPIbβ, GPIX and GPV subunits, all of which are type I transmembrane proteins containing leucine-rich repeat domains. Although all of the subunits were identified decades ago, not until recently did the mechanism of complex assembly begin to emerge from a systematic characterization of inter-subunit interactions. This review summarizes the forces driving the assembly of GPIb-IX-V, discusses their implications for the pathogenesis of Bernard-Soulier syndrome, and identifies questions that remain about the structure and organization of GPIb-IX-V.
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Affiliation(s)
- R Li
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University School of Medicine, Atlanta, GA30322, USA.
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Soderstrom K, Zhang Y, Wilson AR. Altered patterns of filopodia production in CHO cells heterologously expressing zebra finch CB(1) cannabinoid receptors. Cell Adh Migr 2012; 6:91-9. [PMID: 22568949 DOI: 10.4161/cam.20164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recent findings indicate that cannabinoid-altered vocal development involves elevated densities of dendritic spines in a subset of brain regions involved in zebra finch song learning and production suggesting that cannabinoid receptor activation may regulate cell structure. Here we report that activation of zebra finch CB 1 receptors (zfCB 1, delivered by a lentivector to CHO cells) produces dose-dependent biphasic effects on the mean length of filopodia expressed: Low agonist concentrations (3 nM WIN55212-2) increase lengths while higher concentrations reduce them. In contrast, treatment of zfCB 1-expressing cells with the antagonist/inverse agonist SR141716A causes increases in both mean filopodia length and number at 30 and 100 nM. These results demonstrate that CB 1 receptor activation can differentially influence filiopodia elongation depending on dose, and demonstrate that manipulation of cannabinoid receptor activity is capable of modulating cell morphology.
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Affiliation(s)
- Ken Soderstrom
- Department of Pharmacology and Toxicology, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
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Gardiner EE. A GPIb-IX-V complex signaling environment. J Thromb Haemost 2010; 8:1075-6. [PMID: 19566790 DOI: 10.1111/j.1538-7836.2009.03534.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
See also David T, Strassel C, Eckly A, Cazenave J-P, Gachet C, Lanza F. The platelet glycoprotein GPIbbeta intracellular domain participates in von Willebrand factor induced-filopodia formation independently of the Ser 166 phosphorylation site. This issue, pp 1077-87.
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Affiliation(s)
- E E Gardiner
- Australian Centre for Blood Diseases, Monash University, AMREP, Melbourne, Victoria, Australia.
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