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Nam AS, Dusaj N, Izzo F, Murali R, Myers RM, Mouhieddine TH, Sotelo J, Benbarche S, Waarts M, Gaiti F, Tahri S, Levine R, Abdel-Wahab O, Godley LA, Chaligne R, Ghobrial I, Landau DA. Single-cell multi-omics of human clonal hematopoiesis reveals that DNMT3A R882 mutations perturb early progenitor states through selective hypomethylation. Nat Genet 2022; 54:1514-1526. [PMID: 36138229 PMCID: PMC10068894 DOI: 10.1038/s41588-022-01179-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 07/29/2022] [Indexed: 12/13/2022]
Abstract
Somatic mutations in cancer genes have been detected in clonal expansions across healthy human tissue, including in clonal hematopoiesis. However, because mutated and wild-type cells are admixed, we have limited ability to link genotypes with phenotypes. To overcome this limitation, we leveraged multi-modality single-cell sequencing, capturing genotype, transcriptomes and methylomes in progenitors from individuals with DNMT3A R882 mutated clonal hematopoiesis. DNMT3A mutations result in myeloid over lymphoid bias, and an expansion of immature myeloid progenitors primed toward megakaryocytic-erythroid fate, with dysregulated expression of lineage and leukemia stem cell markers. Mutated DNMT3A leads to preferential hypomethylation of polycomb repressive complex 2 targets and a specific CpG flanking motif. Notably, the hypomethylation motif is enriched in binding motifs of key hematopoietic transcription factors, serving as a potential mechanistic link between DNMT3A mutations and aberrant transcriptional phenotypes. Thus, single-cell multi-omics paves the road to defining the downstream consequences of mutations that drive clonal mosaicism.
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Affiliation(s)
- Anna S Nam
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
| | - Neville Dusaj
- New York Genome Center, New York, NY, USA
- Division of Hematology and Medical Oncology, Department of Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
- Tri-Institutional MD-PhD Program, Weill Cornell Medicine, Rockefeller University, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Franco Izzo
- New York Genome Center, New York, NY, USA
- Division of Hematology and Medical Oncology, Department of Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Rekha Murali
- New York Genome Center, New York, NY, USA
- Division of Hematology and Medical Oncology, Department of Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Robert M Myers
- New York Genome Center, New York, NY, USA
- Division of Hematology and Medical Oncology, Department of Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
- Tri-Institutional MD-PhD Program, Weill Cornell Medicine, Rockefeller University, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Tarek H Mouhieddine
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jesus Sotelo
- New York Genome Center, New York, NY, USA
- Division of Hematology and Medical Oncology, Department of Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Salima Benbarche
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Michael Waarts
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Federico Gaiti
- New York Genome Center, New York, NY, USA
- Division of Hematology and Medical Oncology, Department of Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Sabrin Tahri
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Ross Levine
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Lucy A Godley
- Section of Hematology/Oncology, Departments of Medicine and Human Genetics, The University of Chicago, Chicago, IL, USA
| | - Ronan Chaligne
- New York Genome Center, New York, NY, USA
- Division of Hematology and Medical Oncology, Department of Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Irene Ghobrial
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
| | - Dan A Landau
- New York Genome Center, New York, NY, USA.
- Division of Hematology and Medical Oncology, Department of Medicine and Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA.
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, USA.
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2
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Sharifi MJ, Vakili E, Ilkhanipoor H, Zekavat OR, Bordbar M. Elevated CD9 expression as a potential biomarker for diagnosis of Bernard-Soulier syndrome. Blood Coagul Fibrinolysis 2022; 33:159-161. [PMID: 35165218 DOI: 10.1097/mbc.0000000000001117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Diagnosis of inherited platelet glycoprotein disorders is based on specific laboratory techniques such as aggregometry and flow cytometry. Flowcytometry is a powerful method, but equivocal results are produced in some cases. New cluster of differentiation markers could resolve the diagnostic dilemmas. Abnormal expression of CD9 in Bernard-Soulier syndrome (BSS) is recently reported. We aimed to determine the diagnostic significance of CD9 expression in a cohort of Iranian patients with inherited platelet glycoprotein defects. Twelve BSS, 21 Glanzmann thrombasthenia and 16 healthy controls were included in the present study. Flowcytometric diagnosis of BSS and Glanzmann thrombasthenia was made by analysis of CD41/61 and CD42a/42b CD markers. Moreover, phycoerythrin-labelled anti CD9 was examined in patients and healthy controls. The mean fluorescence intensity (MFI) of CD9 among the three groups was compared using suitable statistical methods and a P value of less than 0.05 considered statistically significant. Mean MFI of CD9 was 990.0 in BSS patients versus 421.2 and 317.3 in individuals with Glanzmann thrombasthenia and healthy controls, respectively (P < 0.05). Between the two-group comparison of means by the Mann--Whitney test revealed a P value of less than 0.001 for BSS group versus GT (2.4-fold) and BSS versus healthy controls (2.9-fold). CD9 molecule also expressed differently in patients with Glanzmann thrombasthenia in comparison with healthy controls (P < 0.001), although with a less magnitude (1.3-fold). According to our findings, CD9 is a potential biomarker for laboratory diagnosis of inherited glycoprotein defects, especially to elucidate the ambiguous results in BSS cases.
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Affiliation(s)
- Mohammad Jafar Sharifi
- Division of Laboratory Hematology and Blood Banking, Department of Medical Laboratory Sciences, School of Paramedical Sciences, Shiraz University of Medical Sciences Pediatric Department Pediatric Endocrinology and Metabolism Department, Shiraz University of Medical Sciences Hematology Research Center, Shiraz, Iran
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3
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Seddiq M, Gadgeel M, Persaud Y, Lafferty J, Savaşan S. Severe macrothrombocytopenia with platelet CD9 deficiency responsive to romiplostim. Br J Haematol 2020; 190:e239-e242. [PMID: 32515038 DOI: 10.1111/bjh.16812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marjilla Seddiq
- Division of Hematology/Oncology, Children's Hospital of Michigan, Detroit, MI, USA
| | - Manisha Gadgeel
- Hematology/Oncology Flow Cytometry Laboratory, Children's Hospital of Michigan, Detroit, MI, USA
| | - Yogindra Persaud
- Division of Hematology/Oncology, Children's Hospital of Michigan, Detroit, MI, USA
| | - Jennifer Lafferty
- Division of Hematology/Oncology, Children's Hospital of Michigan, Detroit, MI, USA
| | - Süreyya Savaşan
- Division of Hematology/Oncology, Children's Hospital of Michigan, Detroit, MI, USA.,Hematology/Oncology Flow Cytometry Laboratory, Children's Hospital of Michigan, Detroit, MI, USA.,Pediatric Bone Marrow Transplant Program, Children's Hospital of Michigan, Barbara Ann Karmanos Cancer Center, Wayne State University School of Medicine, Detroit, MI, USA
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4
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Beltrame MP, Malvezzi M, Zanis J, Pasquini R. Flow cytometry as a tool in the diagnosis of Bernard-Soulier Syndrome in Brazilian patients. Platelets 2009; 20:229-34. [DOI: 10.1080/09537100902893784] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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5
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Kotha J, Longhurst C, Appling W, Jennings LK. Tetraspanin CD9 regulates beta 1 integrin activation and enhances cell motility to fibronectin via a PI-3 kinase-dependent pathway. Exp Cell Res 2008; 314:1811-22. [PMID: 18358474 DOI: 10.1016/j.yexcr.2008.01.024] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 01/30/2008] [Accepted: 01/31/2008] [Indexed: 02/07/2023]
Abstract
Tetraspanin CD9 regulates cell motility and other adhesive processes in a variety of tissue types. Using transfected Chinese Hamster Ovary cells as our model system, we examined the cellular pathways critical for CD9 promoted cell migration. alpha 5 beta 1 integrin was directly involved as CD9 enhanced migration was abolished by the alpha 5 beta 1 blocking antibody PB1. Furthermore, the ligand mimetic peptide RGDS, significantly upregulated the expression of a beta1 ligand induced binding site (LIBS) demonstrating for the first time that CD9 expression potentiates beta1 integrin high affinity conformation states. CD9 promoted cell motility was significantly blocked by phosphatidylinositol-3 kinase (PI-3K) inhibitors, wortmannin and LY294002, whereas inhibitors targeting protein kinase C or mitogen-activated protein kinase had no effect. PI-3K dominant/negative cDNA transfections confirmed that PI-3K was an essential component. CD9 enhanced the phosphorylation of the PI-3K substrate, Akt, in response to cell adhesion on FN. CD9 expression also upregulated p130Cas phosphorylation and total protein levels; however, p130Cas siRNA knockdown did not alter the motile phenotype. CD9 enhanced migration was also unaffected by serum deprivation suggesting that growth factors were not critical. Our studies demonstrate that CD9 upregulates beta1 LIBS, and in concert with alpha 5 beta 1, enhances cell motility to FN via a PI-3K dependent mechanism.
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Affiliation(s)
- Jayaprakash Kotha
- Vascular Biology Center of Excellence and the Department of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
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6
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Abstract
The tetraspanins are a superfamily of membrane glycoproteins which facilitate the interaction of membrane and intracellular signalling molecules (e.g., integrins, pro-growth factors and their receptors, protein kinase-C) in the formation of membrane signalling microdomains (sometimes referred to as the tetraspanin web). A proximal localisation/association of tetraspanins with Fc receptors (FcR) has been implied by the repeated rediscoveries of tetraspanins as the targets of antibodies which activate platelets and other blood cells through co-ligation of FcR. Direct evidence of tetraspanin-FcR interactions has come from immunoprecipitation and co-immunofluorescence studies. The functional effects of this interaction remain unclear, but tetraspanins have been identified as negative regulators of FcR signalling independently of co-ligation, indicating potential roles in modulating FcR function in co-ordination with the activity of other signalling/adhesion molecules in the tetraspanin web. Given their capacity to influence FcR signalling, tetraspanins could provide specific therapeutic targets for immune disorders including rheumatoid arthritis, asthma and allergies.
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Affiliation(s)
- Gregory W Moseley
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3080, Australia.
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7
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Sobocka MB, Sobocki T, Babinska A, Hartwig JH, Li M, Ehrlich YH, Kornecki E. Signaling pathways of the F11 receptor (F11R; a.k.a. JAM-1, JAM-A) in human platelets: F11R dimerization, phosphorylation and complex formation with the integrin GPIIIa. J Recept Signal Transduct Res 2005; 24:85-105. [PMID: 15344881 DOI: 10.1081/rrs-120034252] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The F11 receptor (F11R) (a.k.a. Junctional Adhesion Molecule, JAM) was first identified in human platelets as a 32/35 kDa protein duplex that serves as receptor for a functional monoclonal antibody that activates platelets. We have sequenced and cloned the F11R and determined that it is a member of the immunoglobulin (Ig) superfamily of cell adhesion molecules. The signaling pathways involved in F11R-induced platelet activation were examined in this investigation. The binding of M.Ab.F11 to the platelet F11R resulted in granule secretion and aggregation. These processes were found to be dependent on the crosslinking of F11R with the Fc gammaRII by M.Ab.F11. This crosslinking induced actin filament assembly with the conversion of discoidal platelets to activated shapes, leading to the formation of platelet aggregates. We demonstrate that platelet secretion and aggregation through the F11R involves actin filament assembly that is dependent on phosphoinositide-3 kinase activation, and inhibitable by wortmannin. Furthermore, such activation results in an increase in the level of free intracellular calcium, phosphorylation of the 32 and 35 kDa forms of the F11R, F11R dimerization coincident with a decrease in monomeric F11R, and association of the F11R with the integrin GPIIIa and with CD9. On the other hand, F11R-mediated events resulting from the binding of platelets to an immobilized surface of M.Ab.F11 lead to platelet adhesion and spreading through the development of filopodia and lammelipodia. These adhesive processes are induced directly by interaction of M.Ab.F11 with the platelet F11R and are not dependent on the Fc gammaRII. We also report here that the stimulation of the F11R in the presence of nonaggregating (subthreshold) concentrations of the physiological agonists thrombin and collagen, results in supersensitivity of platelets to natural agonists by a F11R-mediated process independent of the Fc gammaRII. The delineation of the two separate F11R-mediated pathways is anticipated to reveal significant information on the role of this cell adhesion molecule in platelet adhesion, aggregation and secretion, and F11R-dependent potentiation of agonist-induced platelet aggregation. The participation of F11R in the formation and growth of platelet aggregates and plaques in cardiovascular disorders, resulting in enhanced platelet adhesiveness and hyperaggregability, may serve in the generation of novel therapies in the treatment of inflammatory thrombosis, heart attack and stroke, and other cardiovascular disorders.
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Affiliation(s)
- Malgorzata B Sobocka
- Department of Anatomy and Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
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8
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Cook GA, Longhurst CM, Grgurevich S, Cholera S, Crossno JT, Jennings LK. Identification of CD9 extracellular domains important in regulation of CHO cell adhesion to fibronectin and fibronectin pericellular matrix assembly. Blood 2002; 100:4502-11. [PMID: 12453879 DOI: 10.1182/blood.v100.13.4502] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CD9, a 24-kDa member of the tetraspanin family, influences cellular growth and development, activation, adhesion, and motility. Our investigation focuses on the hypothesis that the CD9 second extracellular loop (EC2) is important in modulating cell adhesive events. Using a Chinese hamster ovary (CHO) cell expression system, we previously reported that CD9 expression inhibited cell adhesion to fibronectin and fibronectin matrix assembly. For the first time, a functional epitope on CD9 EC2 that regulates these processes is described. Binding of mAb7, an EC2-specific anti-CD9 monoclonal antibody, reversed the CD9 inhibitory activity on CHO cell adhesion and fibronectin matrix assembly. This reversal of cell phenotype also was observed in CHO cells expressing CD9 EC2 truncations. Furthermore, our data showed that the EC2 sequence (173)LETFTVKSCPDAIKEVFDNK(192) was largely responsible for the CD9-mediated CHO cell phenotype. Two peptides, (135)K-V(172) (peptide 5b) and (168)P-I(185) (peptide 6a), selectively blocked mAb7 binding to soluble CD9 and to CD9 on intact cells. These active peptides reversed the influence of CD9 expression on CHO cell adhesion to fibronectin. In addition, confocal microscopy revealed that CD9 colocalized with the integrin alpha(5)beta(1) and cytoskeletal F-actin in punctate clusters on the cell surface, particularly at the cell margins. Immunoprecipitation studies confirmed CD9 association with beta(1) integrin. The cellular distribution and colocalization of focal adhesion kinase and alpha-actinin with cytoskeletal actin was also influenced by CD9 expression. Thus, CD9 may exhibit its effect by modulating the composition of adhesive complexes important in facilitating cell adhesion and matrix assembly.
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MESH Headings
- Actins/metabolism
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/pharmacology
- Antigens, CD/chemistry
- Antigens, CD/genetics
- Antigens, CD/immunology
- Antigens, CD/physiology
- CHO Cells/cytology
- Cell Adhesion/physiology
- Cricetinae
- Cricetulus
- Cytoskeleton/metabolism
- Epitopes/metabolism
- Extracellular Matrix/metabolism
- Fibronectins/metabolism
- Focal Adhesion Kinase 1
- Focal Adhesion Protein-Tyrosine Kinases
- Humans
- Integrin alpha5beta1/metabolism
- Macromolecular Substances
- Membrane Glycoproteins/chemistry
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Membrane Glycoproteins/physiology
- Membrane Proteins/metabolism
- Microscopy, Confocal
- Microscopy, Fluorescence
- Models, Molecular
- Molecular Sequence Data
- Peptide Fragments/chemistry
- Peptide Fragments/pharmacology
- Protein Conformation
- Protein Interaction Mapping
- Protein Structure, Tertiary/physiology
- Protein-Tyrosine Kinases/metabolism
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/physiology
- Sequence Deletion
- Tetraspanin 29
- Transfection
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Affiliation(s)
- George A Cook
- Vascular Biology Center of Excellence, Department of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
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9
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Kawashima M, Doh-ura K, Mekada E, Fukui M, Iwaki T. CD9 expression in solid non-neuroepithelial tumors and infiltrative astrocytic tumors. J Histochem Cytochem 2002; 50:1195-203. [PMID: 12185197 DOI: 10.1177/002215540205000906] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The tetraspan membrane protein CD9 is normally expressed in the mature myelin sheath and is believed to suppress the metastatic potential of certain human tumors. In this study we identified CD9 in a variety of brain tumors by immunohistochemical (IHC) and immunoblotting analyses. We examined 96 tumor samples and three glioma cell lines in addition to a murine brain tumor model of transplanted glioma cells in CD9-deficient mice and control mice. CD9 was expressed not only in solid non-neuroepithelial tumors but also in infiltrative malignant neuroepithelial tumors. Among the neuroepithelial tumors, high-grade astrocytic tumors, including glioblastomas and anaplastic astrocytomas, showed higher immunoreactivity than low-grade cerebral astrocytomas. Thus, CD9 expression in astrocytic tumors correlated with their malignancy. In the murine brain tumor model, transplanted glioma cells were shown to grow and spread through myelinated areas irrespective of the presence or absence of CD9 expression in the recipient's brain. These results indicate that the CD9 expression of astrocytic tumors plays a significant role in the malignancy independent of CD9 expression in the surrounding tissue. This might be explained by the observation that the CD9 molecule is associated with a mitogenic factor, membrane-anchored heparin-binding epidermal growth factor, which is known to be upregulated in malignant gliomas.
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Affiliation(s)
- Masatou Kawashima
- Department of Neuropathology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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10
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Abstract
Anti-platelet antibodies are known to contribute to some types of thrombocytopenia. In this work we investigated anti-platelet antibodies with opposite influence upon activation and kinetics of platelet caspases. A rabbit anti-platelet antibody induced a profound thrombocytopenia, which was associated with an increase of microparticles in plasma and an activation of platelet caspases, as detected by the binding of a carboxyfluorescein-labeled fluoromethyl ketone probe (FAM-VAD-fmk). Furthermore, microparticles and thrombocytopenia were prevented by the injection of a caspase inhibitor ZVAD-fmk. In contrast, an anti-CD18 mAb (M18.2) induced a thrombocytosis, due to an increased platelet life-span and which was evident in wild-type (+/+), but not in CD18-/- or CD87-/-, mice indicating a requirement of these two surface molecules. Activation of caspases was decreased in platelets from mice injected with the M 18.2 mAb, as evidenced by a decreased binding of the VAD probe, detected by flow cytometry, or an increase in the level of pro-caspase-3, seen on Western blots. These observations indicate firstly, that anti-platelet antibodies can either promote or inhibit activation of platelet caspases, and secondly, that the activation of caspases regulates platelet life-span.
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Affiliation(s)
- Pierre F Piguet
- Department of Pathology, University of Geneva, 1 rue M. Servet, CW 1211 Geneva, Switzerland.
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11
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Broberg M, Eriksson C, Nygren H. GpIIb/IIIa is the main receptor for initial platelet adhesion to glass and titanium surfaces in contact with whole blood. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 2002; 139:163-72. [PMID: 11944027 DOI: 10.1067/mlc.2002.121604] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Platelets are the first cells to adhere to a surface in contact with blood and are capable of mediating several different responses after contact with different protein-coated surfaces. They are the main source of growth factors such as platelet-derived growth factor and are therefore important in the healing process. In this study, initial platelet adhesion to and spread on hydrophilic and hydrophobic (methylized) glass and titanium with similar wettability were investigated. Whole coagulating blood was used to simulate the in vivo situation shortly after implantation, in which bleeding precedes inflammation and wound healing. Several different antibodies directed against platelet integrins and receptors (CD9, FcgammaRII, GPIIb/IIIa, vitronectin receptor, GPIb/V/IX) were used in an attempt to block platelet adhesion to the surfaces. Immunofluorescence results show that initial platelet adhesion to all the surfaces we investigated can be almost completely inhibited (approximately 95%) by clone M148, an antibody against the GPIIb/IIIa complex (integrin alpha(IIb)beta(3); CD41/CD61), but not with other antibodies to the separate parts of the integrin. Antibodies known to inhibit fibrinogen binding to GPIIb/IIIa after adenosine diphosphate- and collagen- induced aggregation had very little effect on initial platelet adhesion. None of the other integrins were found to have such an effect on initial platelet adhesion. Antibody clone M148 was furthermore found to inhibit platelet spreading. This study shows that regardless of wettability and the biomaterial used, initial adhesion of platelets appears to be mediated by GPIIb/IIIa binding to surface adsorbed fibrinogen.
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Affiliation(s)
- Marita Broberg
- Department of Anatomy and Cell Biology, University of Gothenburg, Box 420, SE-405 30 Gothenburg, Sweden.
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12
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Seigneuret M, Delaguillaumie A, Lagaudrière-Gesbert C, Conjeaud H. Structure of the tetraspanin main extracellular domain. A partially conserved fold with a structurally variable domain insertion. J Biol Chem 2001; 276:40055-64. [PMID: 11483611 DOI: 10.1074/jbc.m105557200] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The tetraspanin family of membrane glycoproteins is involved in the regulation of cellular development, proliferation, activation, and mobility. We have attempted to predict the structural features of the large extracellular domain of tetraspanins (EC2), which is very important in determining their functional specificity. The tetraspanin EC2 is composed of two subdomains: a conserved three-helix subdomain and a variable secondary structure subdomain inserted within the conserved subdomain. The occurrence of key disulphide bridges and other invariant residues leads to a conserved relative topology of both subdomains and also suggests a structural classification of tetraspanins. Using the CD81 EC2 structure as a template, the structures of two other EC2s were predicted by homology modeling and indicate a conserved shape, in which the variable subdomain is located at one side of the structure. The conserved and variable subdomains might contain sites that correspond, respectively, to common and specific interactions of tetraspanins. The tetraspanin EC2 seems to correspond to a new scheme of fold conservation/variability among proteins, namely the insertion of a structurally variable subdomain within an otherwise conserved fold.
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Affiliation(s)
- M Seigneuret
- Unité Mixte de Recherche, 7033 CNRS, Laboratoire de Physicochimie Biomoléculare et Cellulaire, Université Paris 6, 4 Place Jussieu, 75005 Paris, France
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13
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The GPIb thrombin-binding site is essential for thrombin-induced platelet procoagulant activity. Blood 2000. [DOI: 10.1182/blood.v96.7.2469.h8002469_2469_2478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of the platelet glycoprotein (GP) Ib-V-IX receptor in thrombin activation of platelets has remained controversial although good evidence suggests that blocking this receptor affects platelet responses to this agonist. The mechanism of expression of procoagulant activity in response to platelet agonists is also still obscure. Here, the binding site for thrombin on GPIb is shown to have a key role in the exposure of negatively charged phospholipids on the platelet surface and thrombin generation, in response to thrombin, which also requires protease-activated receptor-1, GPIIb-IIIa, and platelet-platelet contact. Von Willebrand factor binding to GPIb is not essential to initiate development of platelet procoagulant activity. Inhibition of fibrinogen binding to GPIIb-IIIa also failed to block platelet procoagulant activity. Both heparin and low molecular weight heparin block thrombin-induced platelet procoagulant activity, which may account for part of their clinical efficacy. This study demonstrates a new, critical role for platelet GPIb in hemostasis, showing that platelet activation and coagulation are tightly interwoven, which may have implications for alternative therapies for thrombotic diseases.
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14
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Abstract
AbstractThe role of the platelet glycoprotein (GP) Ib-V-IX receptor in thrombin activation of platelets has remained controversial although good evidence suggests that blocking this receptor affects platelet responses to this agonist. The mechanism of expression of procoagulant activity in response to platelet agonists is also still obscure. Here, the binding site for thrombin on GPIb is shown to have a key role in the exposure of negatively charged phospholipids on the platelet surface and thrombin generation, in response to thrombin, which also requires protease-activated receptor-1, GPIIb-IIIa, and platelet-platelet contact. Von Willebrand factor binding to GPIb is not essential to initiate development of platelet procoagulant activity. Inhibition of fibrinogen binding to GPIIb-IIIa also failed to block platelet procoagulant activity. Both heparin and low molecular weight heparin block thrombin-induced platelet procoagulant activity, which may account for part of their clinical efficacy. This study demonstrates a new, critical role for platelet GPIb in hemostasis, showing that platelet activation and coagulation are tightly interwoven, which may have implications for alternative therapies for thrombotic diseases.
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15
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Kaji K, Oda S, Shikano T, Ohnuki T, Uematsu Y, Sakagami J, Tada N, Miyazaki S, Kudo A. The gamete fusion process is defective in eggs of Cd9-deficient mice. Nat Genet 2000; 24:279-82. [PMID: 10700183 DOI: 10.1038/73502] [Citation(s) in RCA: 348] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The cell-surface molecule Cd9, a member of the transmembrane-4 superfamily, interacts with the integrin family and other membrane proteins. and is postulated to participate in cell migration and adhesion. Expression of Cd9 enhances membrane fusion between muscle cells and promotes viral infection in some cells. Fertilization also involves membrane fusion, between gametes. In mammals, the sperm binds to microvilli on the egg surface, and sperm-egg membrane fusion first occurs around the equatorial region of the sperm head12. The fused membrane is then disrupted, and the sperm nucleus as well as the cytoplasm is incorporated into the egg. Cd9 is expressed on the plasma membrane of the mouse egg, and an anti-Cd9 monoclonal antibody inhibits sperm-egg surface interactions. We generated Cd9 mice and found that homozygous mutant females were infertile. Sperm-egg binding was normal, but sperm-egg fusion was almost entirely inhibited in eggs from Cd9 females. Intracellular Ca2 oscillations, which signal fertilization, were absent in almost all mutant eggs; in rare cases, a response occurred after a long time period. In normal animals, Cd9 molecules were expressed on the egg microvilli and became densely concentrated at the sperm attachment site. Thus, our results show that Cd9 is important in the gamete fusion process at fertilization.
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Affiliation(s)
- K Kaji
- Department of Life Science, Tokyo Institute of Technology, Yokohama, Japan
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16
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Kamiguti AS, Theakston RD, Watson SP, Bon C, Laing GD, Zuzel M. Distinct contributions of glycoprotein VI and alpha(2)beta(1) integrin to the induction of platelet protein tyrosine phosphorylation and aggregation. Arch Biochem Biophys 2000; 374:356-62. [PMID: 10666318 DOI: 10.1006/abbi.1999.1627] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Platelet activation by collagen depends principally on two receptors, alpha(2)beta(1) integrin (GPIa-IIa) and GPVI. During this activation, the nonreceptor protein tyrosine kinase pp72(syk) is rapidly phosphorylated, but the precise contribution of alpha(2)beta(1) integrin and GPVI to signaling for this phosphorylation is not clear. We have recently found that proteolysis of platelet alpha(2)beta(1) integrin by the snake venom metalloproteinase, jararhagin, results in inhibition of collagen-induced platelet aggregation and pp72(syk) phosphorylation. In order to verify whether the treatment of platelets with jararhagin had any effect on GPVI signaling, in this study we stimulated platelets treated with either jararhagin or anti-alpha(2)beta(1) antibody with two GPVI agonists, an antibody to GPVI and convulxin. Platelet shape change and phosphorylation of pp72(syk) by both GPVI agonists was preserved, as was the structure and function of GPVI shown by (125)I-labeled convulxin binding to immunoprecipitated GPVI from jararhagin-treated platelets. In contrast, defective platelet aggregation in response to GPVI agonists occurred in both jararhagin-treated and alpha(2)beta(1)-blocked platelets. This apparent cosignaling role of alpha(2)beta(1) integrin for platelet aggregation suggests the possibility of a topographical association of this integrin with GPVI. We found that both platelet alpha(2)beta(1) integrin and GPVI coimmunoprecipitated with alpha(IIb)beta(3) integrin. Since platelet aggregation requires activation of alpha(IIb)beta(3) integrin, defective aggregation in the absence of alpha(2)beta(1) suggests that this receptor may provide a signaling link between GPVI and alpha(IIb)beta(3). Our study therefore demonstrates that platelet signaling leading to pp72(syk) phosphorylation initiated with GPVI engagement by either convulxin or GPVI antibody does not depend on alpha(2)beta(1) integrin. However, alpha(IIb)beta(3) integrin may, in this model, require functional alpha(2)beta(1) integrin for its activation.
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Affiliation(s)
- A S Kamiguti
- Department of Haematology, Royal Liverpool Hospital, Liverpool, United Kingdom.
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17
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Cook GA, Wilkinson DA, Crossno JT, Raghow R, Jennings LK. The tetraspanin CD9 influences the adhesion, spreading, and pericellular fibronectin matrix assembly of Chinese hamster ovary cells on human plasma fibronectin. Exp Cell Res 1999; 251:356-71. [PMID: 10471321 DOI: 10.1006/excr.1999.4596] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of CD9 in cell adhesion and spreading on adhesive proteins was investigated using a transfected Chinese hamster ovary (CHO) cell system. CD9 cell surface expression resulted in reduced adhesion and increased spreading on fibronectin (Fn). Whereas mock-transfected (mock CHO) and naïve CHO cells assumed a typical fibroblast spindle shape morphology, CD9-transfected (CD9-CHO) cells were polygonal with many filipodial projections and exhibited a twofold greater surface area. The spread morphology of CD9-CHO cells, but not mock CHO cells, was inhibited by PB1 mAb blockade of alpha(5)beta(1), suggesting that the coexpression of alpha(5)beta(1) and CD9 influenced cell activity on Fn. The second extracellular loop of CD9 was implicated in regulation of adhesion since reduced CD9-CHO cell adhesion on Fn was reversed by either anti-CD9 antibody ligation to the second extracellular loop or with cells expressing a CD9 mutant lacking the second extracellular loop domain. Using cell adhesion assays and ELISA, we demonstrated CD9 binding to the HEP2/IIICS region of Fn. Finally, CD9 expression resulted in a twofold reduction in Fn-rich pericellular matrix assembly. Our observations show that CD9 dramatically influences CHO cell interactions with Fn and suggest that CD9 has an important role in modulating cell-extracellular matrix interactions.
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Affiliation(s)
- G A Cook
- Department of Medicine, University of Tennessee, Memphis, Tennessee, 38163, USA
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18
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Inngjerdingen M, Waterhouse K, Solum NO. Studies on the dual effects on platelets of a monoclonal antibody to CD9, and on the properties of platelet CD9. Thromb Res 1999; 95:215-27. [PMID: 10515286 DOI: 10.1016/s0049-3848(99)00035-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The article describes effects on human platelets of a murine monoclonal antibody of the IgG2a subtype (clone FN99) directed against the membrane glycoprotein CD9. This antibody exerts a dual action on human platelets in plasma depending on whether the complement system can be activated or not, resulting either in membrane permeabilization or a true platelet aggregation. Secretion from the alpha-granules during permeabilisation was not observed in the sense that the granule-located protein thrombospondin was retained in the platelets, as opposed to what was seen with platelets that had undergone an antibody-induced aggregation. Only a small fraction of P-selectin was found on the surface of the permeabilised platelets. The cytoskeletal protein actin-binding protein (filamin) was profoundly degraded during membrane permeabilisation, however, and scanning electron microscopy showed platelets that were swollen with only a few pseudopodia. Preincubation of platelets with three different antibodies to CD9 showed strong inhibition of a subsequent binding of FITC-labelled Fab fragment of FN99 indicating that antibodies tend to bind in the same area of the CD9 molecule. No association of CD9 to the platelet actin-based cytoskeleton was observed. CD9 was present on the surface of microvesicles derived from calcium ionophore-treated platelets.
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Affiliation(s)
- M Inngjerdingen
- Research Institute for Internal Medicine, Rikshospitalet, Oslo, Norway
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19
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Longhurst CM, White MM, Wilkinson DA, Jennings LK. A CD9, alphaIIbbeta3, integrin-associated protein, and GPIb/V/IX complex on the surface of human platelets is influenced by alphaIIbbeta3 conformational states. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 263:104-11. [PMID: 10429193 DOI: 10.1046/j.1432-1327.1999.00467.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A noncovalently associated complex comprising of CD9, the fibrinogen (Fg) receptor alphaIIbbeta3, integrin-associated protein (IAP), and glycoprotein (GP) Ib/V/IX complex was isolated from Chaps-solubilized human platelets. The CD9 complex was immunoprecipitated by mAbs specific for CD9 (mAb7), IAP (BRIC126), GPIb (SZ1), GPIX (GR-P), beta3 (AP3) and alphaIIb (C3). Additionally, the association between CD9 and alphaIIbbeta3 was demonstrated by ELISA. In this system, CD9 did not bind to vitronectin receptor (alphavbeta3) suggesting that CD9/alphaIIbbeta3 association was alphaIIb-subunit or alphaIIbbeta3-complex dependent. D3, an alphaIIbbeta3-activating mAb that is also an anti-LIBS (ligand-induced binding site), immunoprecipitated primarily alphaIIbbeta3 with GPIb and IAP. CD9 was not detected in D3 immunoprecipitates. D3 binding induced platelet aggregation via direct alphaIIbbeta3 activation and was upregulated by the alphaIIbbeta3 antagonist eptifibatide. In contrast, AP3 and C3 exhibited neither effect. In addition, D3 also inhibited whole blood clot retraction, in contrast to AP3 and C3, suggesting that conformational constraints on alphaIIbbeta3 by D3 binding not only influenced the CD9 complex but also affected alphaIIbbeta3 post receptor occupancy events. The CD9 complex was immunoprecipitated in the presence of eptifibatide, demonstrating that alphaIIbbeta3 receptor occupancy was not sufficient to cause complex dissociation. CD9 complex isolation was also independent of platelet activation, although a twofold increase in the quantity of CD9 complex was seen after platelet activation by alpha-thrombin in the presence of CaCl2 compared with that present in EDTA. Stirred platelets showed fibrinogen-mediated aggregation by alpha-thrombin in the presence of CaCl2 but not with EDTA, suggesting that fibrinogen crosslinking of CD9 complexes via alphaIIbbeta3 could be partially responsible for this increase. These findings imply that the platelet CD9 complex is independent of platelet activation although it is dependent upon the conformation state of alphaIIbbeta3.
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Affiliation(s)
- C M Longhurst
- Department of Medicine, University of Tennessee, Memphis, TN, USA
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Abstract
AbstractCD9 belongs to the transmembrane 4 superfamily, and has been shown to influence cell proliferation, motility, and adhesion. We show here that ligation of CD9 modifies proliferation and/or differentiation of hematopoietic stem/progenitors. Pluripotent EML-C1 hematopoietic cells were cocultured with MS-5 stromal cells in the presence of KMC8.8, an anti-CD9 antibody. Numbers of recovered EML-C1 cells were slightly reduced and the antibody caused the hematopoietic cells to migrate beneath the adherent stromal cell layer. Of particular interest, EML-C1 cells recovered from CD9-ligated cultures had undifferentiated properties. Separate pretreatment of the two cell types with antibody showed that stromal-cell CD9 mediated these responses. Spontaneous expression of erythroid marker was completely blocked and there was a shift towards undifferentiated clonogenic progenitors. Immunoprecipitation studies showed that stromal-cell CD9 associates with the β1 subunit of integrin, as well as a novel 100 kD protein. Antibody cross-linking of cell surface CD9 increased the amount of 100 kD protein that was subsequently coprecipitated with CD9. These observations show that stromal-cell CD9 influences physical interactions with hematopoietic cells and may be one factor that determines the degree of stem cell differentiation.
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Abstract
CD9 belongs to the transmembrane 4 superfamily, and has been shown to influence cell proliferation, motility, and adhesion. We show here that ligation of CD9 modifies proliferation and/or differentiation of hematopoietic stem/progenitors. Pluripotent EML-C1 hematopoietic cells were cocultured with MS-5 stromal cells in the presence of KMC8.8, an anti-CD9 antibody. Numbers of recovered EML-C1 cells were slightly reduced and the antibody caused the hematopoietic cells to migrate beneath the adherent stromal cell layer. Of particular interest, EML-C1 cells recovered from CD9-ligated cultures had undifferentiated properties. Separate pretreatment of the two cell types with antibody showed that stromal-cell CD9 mediated these responses. Spontaneous expression of erythroid marker was completely blocked and there was a shift towards undifferentiated clonogenic progenitors. Immunoprecipitation studies showed that stromal-cell CD9 associates with the β1 subunit of integrin, as well as a novel 100 kD protein. Antibody cross-linking of cell surface CD9 increased the amount of 100 kD protein that was subsequently coprecipitated with CD9. These observations show that stromal-cell CD9 influences physical interactions with hematopoietic cells and may be one factor that determines the degree of stem cell differentiation.
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Kamiguti AS, Markland FS, Zhou Q, Laing GD, Theakston RD, Zuzel M. Proteolytic cleavage of the beta1 subunit of platelet alpha2beta1 integrin by the metalloproteinase jararhagin compromises collagen-stimulated phosphorylation of pp72. J Biol Chem 1997; 272:32599-605. [PMID: 9405475 DOI: 10.1074/jbc.272.51.32599] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Early signaling events in the stimulation of platelets by collagen include the tyrosine phosphorylations of FcR gamma-chain, pp72(syk) and phospholipase Cgamma2. These events are dependent on the main platelet collagen receptor, alpha2beta1 integrin (glycoprotein Ia-IIa complex). We recently found that jararhagin, a 52-kDa snake venom metalloproteinase, selectively inhibits collagen-induced platelet secretion and aggregation in parallel with the cleavage of the beta1 subunit of the alpha2beta1 integrin. The present study demonstrates that jararhagin also interferes with collagen-induced phosphorylation of the protein-tyrosine kinase pp72(syk). This effect is not observed when the platelet aggregation response to collagen is inhibited by two venom RGD-containing disintegrins, contortrostatin and echistatin. These disintegrins inhibit platelet aggregation through their high affinity binding to the platelet alphaIIbbeta3 integrin (glycoprotein IIb-IIIa complex). We also show that mild stimulation by ADP of jararhagin-treated platelets, but not of platelets treated with the RGD-containing disintegrins, restores the collagen-induced platelet aggregation. ADP also restored both pp72(syk) and pleckstrin phosphorylation of jararhagin-treated platelets in response to collagen, presumably via interaction of collagen with ADP-activated alphaIIbbeta3 integrin. Thus, RGD-containing disintegrins do not interfere with agonist-induced pp72(syk) phosphorylation but inhibit aggregation through occupancy of the alphaIIbbeta3 integrin. Conversely, jararhagin affects early platelet signaling events in response to collagen through its effects on the alpha2beta1 integrin without interfering with the function of the alphaIIbbeta3 integrin. Our demonstration that the degradation of the beta1 subunit of alpha2beta1 by jararhagin results in the loss of pp72(syk) phosphorylation, suggests that this subunit is critically involved in collagen-induced platelet signaling.
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Affiliation(s)
- A S Kamiguti
- Department of Haematology, Royal Liverpool Hospital, University of Liverpool, Liverpool L69 3BX, United Kingdom
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24
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Shattil SJ, Ginsberg MH. Perspectives series: cell adhesion in vascular biology. Integrin signaling in vascular biology. J Clin Invest 1997; 100:1-5. [PMID: 9202049 PMCID: PMC508157 DOI: 10.1172/jci119500] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- S J Shattil
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
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