title: Intra- and extracellular plasminogen activator inhibitor-1 regulate effect of vitronectin against radiation-induced endothelial cell death.
abstract: Plasminogen activator inhibitor-1 (PAI-1) is induced by radiation resulting in endothelial cell impairment, potentially leading to multiple organ failure. Vitronectin (VN) is a 75-kDa glycoprotein (VN75) cleaved into two forms (VN75or VN65/10) by furin, which is regulated by intracellular PAI-1. VN protects against radiation-induced endothelial cell death, but the mechanisms involved in VN processing and its interactions with intra- and extracellular PAI-1 remain unclear. We examined these processes in cells in vitro using recombinant proteins or overexpression of VN and PAI-1 genes, including furin-susceptible (T381) and furin-resistant VN (A381). VN processing was analyzed using a mutant PAI-1 with relatively weaker binding to VN. VN function was evaluated by survival of radiation-damaged endothelial cells. Wild-type, but not mutant PAI-1 inhibited furin-dependent VN processing. Gene transfer revealed that furin-susceptible VN was processed more than the furin-resistant form, but processing of both was inhibited by PAI-1 overexpression. Intracellular PAI-1 formed a complex with VN75(T381) in cells and media, and the VN75form was secreted preferentially. Only VN75protected against radiation-induced endothelial cell death, in which its effect was abolished by wild-type but not mutant PAI-1. These findings indicate that intracellular PAI-1 inhibits VN processing and protects against radiation-induced endothelial cell death.
authors.affiliation: Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Hazawa
authors.affiliation: Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yasuda
authors.affiliation: Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Saotome-Nakamura
authors.affiliation: Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tomiyama
authors.affiliation: Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Chizuka
authors.initials: C
authors.lastname: Obara
authors.affiliation: Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Takaya
authors.initials: T
authors.lastname: Goto
authors.affiliation: Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba, Japan. Electronic address: tajima@nirs.go.jp.
authors.forename: Katsushi
authors.initials: K
authors.lastname: Tajima
mesh_terms: D016923:Cell Death / Q000528:radiation effects; D042783:Endothelial Cells / Q000378:metabolism* / Q000528:radiation effects; D045683:Furin / Q000378:metabolism; D057809:HEK293 Cells; D056945:Hep G2 Cells; D006801:Humans; D009154:Mutation; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D011832:Radiation Injuries / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D019096:Vitronectin / Q000235:genetics / Q000378:metabolism*
chemical_list: D017395:Plasminogen Activator Inhibitor 1; C051321:SERPINE1 protein, human; D019096:Vitronectin; D045683:Furin
keywords: Endothelium; Furin; Plasminogen activator inhibitor 1; Radiation; Vitronectin