title: Thrombospondin-1 differentially induces chemotaxis and DNA synthesis of human venous smooth muscle cells at the receptor-binding level.
abstract: Thrombospondin-1 is a large matricellular protein that acts as a pleiotropic growth factor for human vascular smooth muscle cells, and may play a role in the progression of vascular disease. Although we have previously demonstrated the dependence of both thrombospondin-1-stimulated cell chemotaxis and proliferation on tyrosine kinases, the receptor mechanisms involved remain obscure. This investigation aims to determine the nature of the receptor(s) involved in the cellular responses to thrombospondin-1. Cellular signals were identified by western blotting following cell stimulation, while cellular responses were assessed by measuring DNA synthesis and chemotaxis. These data demonstrate that thrombospondin-1-induced cell chemotaxis can be inhibited by a peptide containing the Arg-Gly-Asp motif, a function-blocking alpha(v)beta(3) antibody, a function-blocking integrin-associated protein (IAP) antibody and pertussis toxin, while thrombospondin-1-stimulated DNA synthesis is inhibited by a function-blocking alpha(3)beta(1) antibody. Similarly the Arg-Gly-Asp-containing peptide inhibits tyrosine phosphorylation of focal adhesion kinase and the p85 regulatory subunit of phosphatidylinositol 3-kinase, but does not significantly affect tyrosine phosphorylation, or activation, of extracellular-regulated kinase. These data suggest that soluble thrombospondin-1 interacts with human vascular smooth muscle cells via two independent and separable receptor-binding sites, to differentially stimulate cell chemotaxis and DNA synthesis.
authors.affiliation: Clinical Pharmacology, National Heart and Lung Institute, Imperial College of Science, Technology & Medicine, QEQM Wing, St Mary's Hospital, Paddington, London W2 1NY, UK. j.lymn@ic.ac.uk
authors.forename: Joanne S
authors.initials: JS
authors.lastname: Lymn
authors.forename: Mahendra K
authors.initials: MK
authors.lastname: Patel
authors.forename: Gerard F
authors.initials: GF
authors.lastname: Clunn
authors.forename: Sarafina J
authors.initials: SJ
authors.lastname: Rao
authors.forename: Karen L
authors.initials: KL
authors.lastname: Gallagher
authors.forename: Alun D
authors.initials: AD
authors.lastname: Hughes
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D015703:Antigens, CD / Q000494:pharmacology; D001665:Binding Sites / Q000187:drug effects / Q000235:genetics; D018955:CD36 Antigens / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D051928:CD47 Antigen; D002352:Carrier Proteins / Q000494:pharmacology; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology*; D004247:DNA / Q000096:biosynthesis* / Q000187:drug effects; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000037:antagonists & inhibitors; D019950:Mitogen-Activated Protein Kinase 1 / Q000187:drug effects / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D037342:Pertussis Toxin / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D019700:Thrombospondin 1 / Q000378:metabolism* / Q000494:pharmacology; D014680:Veins / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000906:Antibodies; D015703:Antigens, CD; D018955:CD36 Antigens; D051928:CD47 Antigen; C497894:CD47 protein, human; D002352:Carrier Proteins; D039302:Integrin alphaVbeta3; D009842:Oligopeptides; D019700:Thrombospondin 1; C047981:arginyl-glycyl-aspartic acid; D004247:DNA; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D019950:Mitogen-Activated Protein Kinase 1