title: Regulated von Willebrand factor secretion is associated with agonist-specific patterns of cytoskeletal remodeling in cultured endothelial cells.
abstract: von Willebrand factor (vWF), an adhesive glycoprotein involved in primary hemostasis, is stored and released from endothelial secretory granules called Weibel-Palade bodies. Regulated secretion occurs in reaction either to [Ca(2+)](i)-raising agents (histamine or thrombin) or to cAMP-raising agents (epinephrine, adenosine, or forskolin). We investigated the pattern of release and the cytoskeletal requirements for secretion in response to these 2 classes of agonists. Secretion induced by [Ca(2+)](i)-raising agents involves peripheral and central granules and is inhibited by colchicine-induced microtubule disruption. It is accompanied by Rho-dependent stress fiber formation and cell retraction. Secretion and remodeling occur in the same individual cells. However, secretion is potentiated by cytochalasin E and C3 toxin, indicating that stress fiber formation antagonizes vWF secretion. In contrast, vWF secretion induced by cAMP-raising agents involves the release of only peripheral granules (implying less vWF release on a per cell basis) and is not inhibited by microtubule disruption. cAMP-mediated secretion is accompanied by disruption of stress fibers, strengthening of the cortical actin rim, and preservation of cell-cell contacts. It is unaffected by cytochalasins or C3 toxin. In contrast to [Ca(2+)](i)-raising agents, cAMP-raising agents induce secretion without cell retraction/intercellular gap formation. Thus, they are likely to play a physiological role in the regulation of endothelial vWF secretion and, therefore, of plasma vWF levels.
authors.affiliation: Division de Biochimie Clinique, Department of Internal Medicine, Geneva, Switzerland. Ulrich.Vscher@medecine.unige.ch
authors.forename: U M
authors.initials: UM
authors.lastname: Vischer
authors.forename: H
authors.initials: H
authors.lastname: Barth
authors.forename: C B
authors.initials: CB
authors.lastname: Wollheim
mesh_terms: D036002:ADP Ribose Transferases / Q000494:pharmacology; D000199:Actins / Q000032:analysis; D000241:Adenosine / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D001905:Botulinum Toxins; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D048429:Cell Size / Q000502:physiology; D002478:Cells, Cultured; D003078:Colchicine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D003571:Cytochalasin B / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D004837:Epinephrine / Q000494:pharmacology; D020690:GTPase-Activating Proteins / Q000378:metabolism; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D007476:Ionophores / Q000494:pharmacology; D008870:Microtubules / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D009218:Myosins / Q000032:analysis; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D013566:Sympathomimetics / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology; D014665:Vasodilator Agents / Q000494:pharmacology; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D000199:Actins; D020690:GTPase-Activating Proteins; D007476:Ionophores; D019384:Nucleic Acid Synthesis Inhibitors; D013566:Sympathomimetics; D014665:Vasodilator Agents; C085379:rho GTPase-activating protein; D014841:von Willebrand Factor; D005576:Colforsin; D015638:Cytochalasin D; D000001:Calcimycin; D003571:Cytochalasin B; D006632:Histamine; D000242:Cyclic AMP; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D013917:Thrombin; D001905:Botulinum Toxins; D009218:Myosins; D000241:Adenosine; D003078:Colchicine; D002118:Calcium; D004837:Epinephrine