title: Activation of AP-1 transcription factors differentiates FGF2 and vascular endothelial growth factor regulation of endothelial nitric-oxide synthase expression in placental artery endothelial cells.
abstract: FGF2 (fibroblast growth factor 2), but not vascular endothelial growth factor (VEGF), stimulates sustained activation of ERK2/1 for endothelial NOS3 (nitric-oxide synthase 3) protein expression in ovine fetoplacental artery endothelial cells (oFPAEC). We deciphered herein the downstream signaling of ERK2/1 responsible for NOS3 expression by FGF2 in oFPAEC. FGF2, but not VEGF, increased NOS3 mRNA levels without altering its degradation. FGF2, but not VEGF, trans-activated sheep NOS3 promoter, and this was dependent on ERK2/1 activation. FGF2 did not trans-activate NOS3 promoters with deletions upstream of the consensus AP-1 site (TGAGTC A, -678 to -685). Trans-activation of wild-type NOS3 promoter by FGF2 was significantly inhibited when either the AP-1 or the cAMP-response element (CRE)-like sequence (TGCGTCA, -752 to -758) was mutated and was completely blocked when both were mutated. EMSA analyses showed that FGF2, but not VEGF, stimulated AP-1 and CRE DNA-protein complexes primarily composed of JunB and Fra1. Chromatin immunoprecipitation assays confirmed JunB/Fra1 binding to NOS3 promoter AP-1 and CRE elements in intact cells. FGF2, but not VEGF, stimulated JunB and Fra1 expressions; all preceded NOS3 up-regulation and were inhibited by PD98059. Down-regulation of JunB or Fra-1, but not c-Jun, blocked FGF2 stimulation of NOS3 expression and NO production. AP-1 inhibition suppressed FGF2 stimulation of NOS3 expression in human umbilical vein EC and uterine artery endothelial cells. Thus, FGF2 induction of NOS3 expression is mainly mediated by AP-1-dependent transcription involving JunB and Fra1 up-regulation via sustained ERK2/1 activation in endothelial cells.
authors.affiliation: Department of Reproductive Medicine, University of California San Diego, La Jolla, California 92093, USA.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Mata-Greenwood
authors.forename: Wu-xiang
authors.initials: WX
authors.lastname: Liao
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Zheng
authors.forename: Dong-bao
authors.initials: DB
authors.lastname: Chen
mesh_terms: D000818:Animals; D001158:Arteries / Q000201:enzymology*; D042783:Endothelial Cells / Q000378:metabolism*; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D011270:Pregnancy, Animal; D012756:Sheep; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D015533:Transcriptional Activation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D018808:Transcription Factor AP-1; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D052250:Nitric Oxide Synthase Type III