title: Oxidized low-density lipoprotein inhibits vascular endothelial growth factor-induced endothelial progenitor cell differentiation.
abstract: 1. Bone marrow-derived endothelial progenitor cells (EPC) in the peripheral blood of adult animals and humans have been shown to be incorporated into neovascularization. In contrast, hypercholesterolaemia impairs angiogenesis and collateral vessel formation in response to regional tissue ischaemia. We investigated whether oxidized LDL (oxLDL) affected human EPC differentiation. 2. When isolated human mononuclear cells (MNC) were incubated with vascular endothelial growth factor (VEGF), the number of differentiated, adherent EPC, as assessed by an in vitro culture assay, was increased in a dose-dependent manner (P < 0.01). When MNC were incubated with oxLDL at 1, 5 and 10 microg/mL in the presence of 100 ng/mL VEGF for 24 h, oxLDL dose-dependently reduced the number of differentiated, adherent EPC. 3. Vascular endothelial growth factor-induced EPC differentiation was significantly inhibited by pharmacological phosphatidylinositol 3-kinase blockers (either 10 nmol/L wortmannin or 10 micromol/L LY294002). Interestingly, immunoblotting analysis revealed that oxLDL dose-dependently led to dephosphorylation and, thus, deactivation of Akt in the presence of VEGF. Finally, these inhibitory effects induced by oxLDL were abolished by pretreatment with 1 micromol/L atorvastatin (P < 0.01). 4. Our data indicate that oxLDL inhibits VEGF-induced EPC differentiation through the dephosphorylation of Akt.
authors.affiliation: Department of Cardiovascular Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama City, Wakayama 641-8510, Japan. t-imani@wakayama-med.ac.jp
authors.forename: Toshio
authors.initials: T
authors.lastname: Imanishi
authors.forename: Takuzo
authors.initials: T
authors.lastname: Hano
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nishio
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D008077:Lipoproteins, LDL; D042461:Vascular Endothelial Growth Factor A; C099252:oxidized low density lipoprotein