title: Angiopoietin-1 inhibits irradiation- and mannitol-induced apoptosis in endothelial cells.
abstract: OBJECTIVE
  Angiopoietin-1 (Ang1) is a vasculogenic factor that signals through the endothelial cell-specific Tie2 receptor tyrosine kinase. We recently reported that Ang1 prevented apoptosis induced by serum deprivation in endothelial cells. In this study, we examined whether Ang1 prevents apoptosis in endothelial cells treated with irradiation or clinical concentrations of mannitol.
  
  
  RESULTS
  ++Ang1 prevented irradiation- and mannitol-induced apoptosis in human umbilical vein endothelial cells in a dose-dependent manner. Pretreatment with soluble Tie2 receptor, but not Tie1 receptor, blocked the antiapoptotic effect of Ang1. Two phosphatidylinositol 3'-kinase (PI3-kinase)-specific inhibitors, wortmannin and LY294002, blocked the Ang1-induced antiapoptotic effect. The antiapoptotic potency of Ang1 was similar to or greater than that of vascular endothelial growth factor, basic fibroblast growth factor, and endothelin-1. Ang1 also prevented apoptosis in cultured endothelial cells from porcine pulmonary and coronary arteries and in endothelial cells of explanted rat aorta.
  
  
  CONCLUSIONS
  Ang1 promotes the survival of endothelial cells in irradiation- and mannitol-induced apoptosis through Tie2 receptor binding and PI3-kinase activation. Pretreatment with Ang1 could be beneficial in maintaining normal endothelial cell integrity during intracoronary irradiation or systemic mannitol therapy.
authors.affiliation: National Creative Research Initiatives Center for Cardiac Regeneration, Departments of Obstetrics and Gynecology, Chonbuk National University, Chonju, Republic of Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Kwak
authors.forename: S J
authors.initials: SJ
authors.lastname: Lee
authors.forename: Y H
authors.initials: YH
authors.lastname: Lee
authors.forename: C H
authors.initials: CH
authors.lastname: Ryu
authors.forename: K N
authors.initials: KN
authors.lastname: Koh
authors.forename: H Y
authors.initials: HY
authors.lastname: Choi
authors.forename: G Y
authors.initials: GY
authors.lastname: Koh
mesh_terms: D042683:Angiopoietin-1; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology / Q000187:drug effects; D016207:Cytokines / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects*; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D008297:Male; D008353:Mannitol / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects; D009363:Neoplasm Proteins / Q000502:physiology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D011518:Proto-Oncogene Proteins; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D042787:Receptor, TIE-2; D013552:Swine; D014471:Umbilical Veins / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects
chemical_list: C467630:ANGPT1 protein, human; D042683:Angiopoietin-1; C467629:Angpt1 protein, rat; D016207:Cytokines; D006133:Growth Substances; C105373:MEN1 protein, human; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D008353:Mannitol; D019869:Phosphatidylinositol 3-Kinases; D042787:Receptor, TIE-2