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Hunter EJ, Hamaia SW, Kim PSK, Malcor JDM, Farndale RW. The effects of inhibition and siRNA knockdown of collagen-binding integrins on human umbilical vein endothelial cell migration and tube formation. Sci Rep 2022; 12:21601. [PMID: 36517525 PMCID: PMC9751114 DOI: 10.1038/s41598-022-25937-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/07/2022] [Indexed: 12/15/2022] Open
Abstract
Blood vessels in the body are lined with endothelial cells which have vital roles in numerous physiological and pathological processes. Collagens are major constituents of the extracellular matrix, and many adherent cells express several collagen-binding adhesion receptors. Here, we study the endothelium-collagen interactions mediated by the collagen-binding integrins, α1β1, α2β1, α10β1 and α11β1 expressed in human umbilical vein endothelial cells (HUVECs). Using qPCR, we found expression of the α10 transcript of the chondrocyte integrin, α10β1, along with the more abundant α2, and low-level expression of α1. The α11 transcript was not detected. Inhibition or siRNA knockdown of the α2-subunit resulted in impaired HUVEC adhesion, spreading and migration on collagen-coated surfaces, whereas inhibition or siRNA knockdown of α1 had no effect on these processes. In tube formation assays, inhibition of either α1 or α2 subunits impaired the network complexity, whereas siRNA knockdown of these integrins had no such effect. Knockdown of α10 had no effect on cell spreading, migration or tube formation in these conditions. Overall, our results indicate that the collagen-binding integrins, α1β1 and α2β1 play a central role in endothelial cell motility and self-organisation.
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Affiliation(s)
- Emma J Hunter
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, CB2 1QW, UK
- Stem Cell and Brain Research Institute, Université Lyon 1, INSERM U1208, 18 Avenue Doyen Lépine, 69500, Bron, France
| | - Samir W Hamaia
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, CB2 1QW, UK
| | - Peter S-K Kim
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, CB2 1QW, UK
| | - Jean-Daniel M Malcor
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, CB2 1QW, UK
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique, UMS3444 BioSciences Gerland-Lyon Sud, UMR5305, CNRS/Université Lyon 1, Lyon, France
| | - Richard W Farndale
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, CB2 1QW, UK.
- CambCol Laboratories Ltd, 18 Oak Lane, Littleport, Ely, CB6 1QZ, UK.
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Wei H, Malcor JDM, Harper MT. Lipid rafts are essential for release of phosphatidylserine-exposing extracellular vesicles from platelets. Sci Rep 2018; 8:9987. [PMID: 29968812 PMCID: PMC6030044 DOI: 10.1038/s41598-018-28363-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/21/2018] [Indexed: 12/21/2022] Open
Abstract
Platelets protect the vascular system during damage or inflammation, but platelet activation can result in pathological thrombosis. Activated platelets release a variety of extracellular vesicles (EVs). EVs shed from the plasma membrane often expose phosphatidylserine (PS). These EVs are pro-thrombotic and increased in number in many cardiovascular and metabolic diseases. The mechanisms by which PS-exposing EVs are shed from activated platelets are not well characterised. Cholesterol-rich lipid rafts provide a platform for coordinating signalling through receptors and Ca2+ channels in platelets. We show that cholesterol depletion with methyl-β-cyclodextrin or sequestration with filipin prevented the Ca2+-triggered release of PS-exposing EVs. Although calpain activity was required for release of PS-exposing, calpain-dependent cleavage of talin was not affected by cholesterol depletion. P2Y12 and TPα, receptors for ADP and thromboxane A2, respectively, have been reported to be in platelet lipid rafts. However, the P2Y12 antagonist, AR-C69931MX, or the cyclooxygenase inhibitor, aspirin, had no effect on A23187-induced release of PS-exposing EVs. Together, these data show that lipid rafts are required for release of PS-exposing EVs from platelets.
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Affiliation(s)
- Hao Wei
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | | | - Matthew T Harper
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom.
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Watson BR, White NA, Taylor KA, Howes JM, Malcor JDM, Bihan D, Sage SO, Farndale RW, Pugh N. Zinc is a transmembrane agonist that induces platelet activation in a tyrosine phosphorylation-dependent manner. Metallomics 2016; 8:91-100. [PMID: 26434726 DOI: 10.1039/c5mt00064e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Following platelet adhesion and primary activation at sites of vascular injury, secondary platelet activation is induced by soluble platelet agonists, such as ADP, ATP, thrombin and thromboxane. Zinc ions are also released from platelets and damaged cells and have been shown to act as a platelet agonist. However, the mechanism of zinc-induced platelet activation is not well understood. Here we show that exogenous zinc gains access to the platelet cytosol and induces full platelet aggregation that is dependent on platelet protein tyrosine phosphorylation, PKC and integrin αIIbβ3 activity and is mediated by granule release and secondary signalling. ZnSO4 increased the binding affinity of GpVI, but not integrin α2β1. Low concentrations of ZnSO4 potentiated platelet aggregation by collagen-related peptide (CRP-XL), thrombin and adrenaline. Chelation of intracellular zinc reduced platelet aggregation induced by a number of different agonists, inhibited zinc-induced tyrosine phosphorylation and inhibited platelet activation in whole blood under physiologically relevant flow conditions. Our data are consistent with a transmembrane signalling role for zinc in platelet activation during thrombus formation.
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Affiliation(s)
- Ben R Watson
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, UK
| | - Nathan A White
- Department of Biomedical and Forensic Sciences, Anglia Ruskin University, East Road, Cambridge, UK.
| | - Kirk A Taylor
- Department of Biomedical and Forensic Sciences, Anglia Ruskin University, East Road, Cambridge, UK.
| | - Joanna-Marie Howes
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, UK
| | - Jean-Daniel M Malcor
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, UK
| | - Dominique Bihan
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, UK
| | - Stewart O Sage
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, UK
| | - Richard W Farndale
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, UK
| | - Nicholas Pugh
- Department of Biochemistry, University of Cambridge, Downing Site, Cambridge, UK and Department of Biomedical and Forensic Sciences, Anglia Ruskin University, East Road, Cambridge, UK.
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