title: Activation of the VEGFR1 chromatin domain: an angiogenic signal-ETS1/HIF-2alpha regulatory axis.
abstract: Angiogenesis is induced by multiple growth factors including vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2). In vascular endothelium VEGF signals through two receptor-tyrosine kinases, VEGFR1 and VEGFR2. The VEGFR1 gene encodes both a receptor-tyrosine kinase and a secreted splice variant, soluble VEGFR1. Whereas VEGFR1 is essential for vascular development, mechanisms that regulate VEGFR1 expression in endothelial cells are poorly understood. We demonstrate here that in endothelial cells, FGF2 and epidermal growth factor (EGF) signaling induce VEGFR1 mRNA expression in a combinatorial fashion. EGF/FGF2-mediated VEGFR1 induction is mediated via functional interaction of transcription factors ETS1 and HIF-2alpha. Mechanistic analyses revealed that in endothelial cells EGF/FGF2 signaling induces ETS1 expression, increases HIF-2alpha protein level in absence of hypoxia, and recruits both ETS1 and HIF-2alpha to the VEGFR1 chromatin domain. Knockdown of ETS1 and HIF-2alpha by RNA interference inhibits EGF/FGF2-induced VEGFR1 expression, and loss of expression is associated with impaired RNA-polymerase II recruitment and histone modifications at the VEGFR1 promoter region. In addition, using a mouse embryonic stem cell in vitro differentiation system, we found that induction of VEGFR1 in embryoid bodies is also associated with ETS1 and HIF-2alpha recruitment to the VEGFR1 locus. These results establish an angiogenic signal-ETS1/HIF-2alpha axis that regulates the VEGFR1 chromatin domain to induce VEGFR1 transcription in endothelial cells and in differentiating embryonic stem cells.
authors.affiliation: Institute of Maternal-Fetal Biology and the Division of Cancer and Developmental Biology, Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas 66160.
authors.forename: Debasree
authors.initials: D
authors.lastname: Dutta
authors.affiliation: Institute of Maternal-Fetal Biology and the Division of Cancer and Developmental Biology, Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas 66160.
authors.forename: Soma
authors.initials: S
authors.lastname: Ray
authors.affiliation: Institute of Maternal-Fetal Biology and the Division of Cancer and Developmental Biology, Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas 66160.
authors.forename: Jay L
authors.initials: JL
authors.lastname: Vivian
authors.affiliation: Institute of Maternal-Fetal Biology and the Division of Cancer and Developmental Biology, Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas 66160. Electronic address: spaul2@kumc.edu.
authors.forename: Soumen
authors.initials: S
authors.lastname: Paul
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D002460:Cell Line; D002843:Chromatin / Q000737:chemistry*; D053595:Embryonic Stem Cells / Q000378:metabolism; D005786:Gene Expression Regulation; D006657:Histones / Q000378:metabolism; D006801:Humans; D051379:Mice; D009389:Neovascularization, Pathologic; D011493:Protein Kinase C / Q000378:metabolism; D017434:Protein Structure, Tertiary; D050784:Proto-Oncogene Protein c-ets-1 / Q000378:metabolism*; D015398:Signal Transduction; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000737:chemistry*; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D002843:Chromatin; D006657:Histones; D011493:Protein Kinase C; D050784:Proto-Oncogene Protein c-ets-1; D040281:Vascular Endothelial Growth Factor Receptor-1; D000099162:Endothelial PAS Domain-Containing Protein 1; C494041:ETS1 protein, human