title: Flk-1/KDR mediates ethanol-stimulated endothelial cell Notch signaling and angiogenic activity.
abstract: We previously reported that ethanol (EtOH) stimulates endothelial angiogenic activity mediated via a notch- and angiopoietin-1 (Ang-1) pathway. As crosstalk exists between notch and vascular endothelial growth factor (VEGF) signaling, we examined whether the VEGF receptor (VEGFR) Flk-1 (fetal liver kinase 1) mediates EtOH-stimulated notch signaling and angiogenic activity.
  
  
  RESULTS
  Treatment of human coronary artery endothelial cells (HCAECs) with EtOH (1-50 mM, 24 h) dose-dependently increased Flk-1 expression with a maximum increase observed at 25 mM EtOH. Ethanol treatment activated both Flk-1 and Flt-1 (FMS-like tyrosine kinase 1) as indicated by their phosphorylation, and subsequent stimulation of Akt. EtOH activation of Flk-1 was inhibited by the VEGFR inhibitor SU5416. Gene silencing of Flk-1 using small interfering RNA inhibited the EtOH-induced increase in notch receptors 1 and 4 and notch target gene (hairy enhancer of split-related transcription factor 1) mRNA. Knockdown of Flk-1 inhibited EtOH-induced Ang-1/Tie-2 mRNA expression and blocked EtOH-induced HCAEC network formation on Matrigel, a response that was restored by notch ligand, notch ligand delta-like ligand 4, treatment. In vivo, moderate alcohol feeding increased vascular remodeling in mouse ischemic hindlimbs.
  
  
  CONCLUSIONS
  These data demonstrate that EtOH activates Flk-1 and Flt-1 receptors in HCAECs and promotes angiogenic activity via an Flk-1/notch pathway. These effects of EtOH may be relevant to the influence of moderate alcohol consumption on cardiovascular health.
authors.affiliation: Department of Surgery, University of Rochester Medical Center, Rochester, N.Y., USA.
authors.forename: David
authors.initials: D
authors.lastname: Morrow
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Hatch
authors.forename: Katie
authors.initials: K
authors.lastname: Hamm
authors.forename: Paul A
authors.initials: PA
authors.lastname: Cahill
authors.forename: Eileen M
authors.initials: EM
authors.lastname: Redmond
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000494:pharmacology; D003331:Coronary Vessels / Q000166:cytology; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology*; D005263:Femoral Artery; D006614:Hindlimb / Q000098:blood supply; D006801:Humans; D007511:Ischemia / Q000378:metabolism*; D008026:Ligation; D008297:Male; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics; D051880:Receptors, Notch / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D002492:Central Nervous System Depressants; D034741:RNA, Small Interfering; D051880:Receptors, Notch; D000431:Ethanol; C000588866:KDR protein, human; C000592875:Kdr protein, mouse; D040301:Vascular Endothelial Growth Factor Receptor-2