title: Heterogeneity of microfibrils: role of thrombospondin-microfibrils in the thrombogenicity of the subendothelium.
abstract: We report the results of an immunogold electron microscopical analysis on microfibrils from the arterial subendothelium showing that thrombospondin (TSP) is present on 40 nm-diameter structures joining 8-10 nm-diameter microfibrils containing fibrillin. They differ from type VI collagen which forms 3-5 nm-diameter microfibrils. TSP containing microfibrils (TSP-MF) extracted from human umbilical arteries did not contain fibrillin or type VI collagen. Blood platelet interactions with TSP-MF were not modified by anti-fibrillin or anti-type VI collagen antibodies. In situ, vWF was bound to cross-linked microfibrils, at the level of their 40 nm junction, and a double-labeling with the anti-thrombospondin and anti-vWF antibodies was observed. In vitro, vWF binding to TSP-MF was not inhibited by anti-fibrillin or anti-type VI collagen antibodies. These results suggest a structural and functional heterogeneity of microfibrils and emphasize the role of TSP-MF in the thrombogenicity of the subendothelium.
authors: INSERM U. 353, hôpital Saint-Louis, Paris, France.
authors: F
authors: F
authors: Fauvel-Lafève
authors: B
authors: B
authors: Arbeille
authors: C
authors: C
authors: de Romeuf
authors: M
authors: M
authors: Lemesle
authors: Y J
authors: YJ
authors: Legrand
mesh_terms: D003094:Collagen / Q000276:immunology; D004730:Endothelium, Vascular / Q000276:immunology*; D016326:Extracellular Matrix Proteins; D000071837:Fibrillins; D006801:Humans; D066298:In Vitro Techniques; D008562:Membrane Glycoproteins / Q000276:immunology*; D008840:Microfilament Proteins / Q000276:immunology / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D010974:Platelet Aggregation; D019699:Thrombospondins; D014841:von Willebrand Factor / Q000276:immunology
chemical_list: D016326:Extracellular Matrix Proteins; D000071837:Fibrillins; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D019699:Thrombospondins; D014841:von Willebrand Factor; D003094:Collagen