title: Activated blood coagulation factor X (FXa) induces angiogenic growth factor expression in human retinal pigment epithelial cells.
abstract: OBJECTIVE
  To determine the transcriptional regulation of the blood coagulation factor X (FX) in cultured human retinal pigment epithelial (RPE) cells, and whether the effects of FXa on the chemotaxis and expression of angiogenic growth factors are mediated by autocrine growth factor signaling.
  
  
  METHODS
  Alterations in gene expression and secretion of growth factors were determined by real-time RT-PCR and ELISA, respectively. Cellular proliferation and chemotaxis were investigated with a bromodeoxyuridine immunoassay and a Boyden chamber assay, respectively.
  
  
  RESULTS
  The gene expression of FX in RPE cells was increased by hypoxia and prostaglandin E(2), and decreased by blood serum, FXa, thrombin, transforming growth factor beta (TGF-β1), and platelet-derived growth factor (PDGF). The serum-induced downregulation of FX was mediated by thrombin and TGF-β signaling. FXa induced chemotaxis of RPE cells via activation of the p38 mitogen-activated protein kinase signal transduction pathway. FXa also induced expression of vascular endothelial growth factor (VEGF), heparin-binding epidermal growth factor-like growth factor (HB-EGF), and basic fibroblast growth factor (bFGF), as well as release of VEGF, bFGF, and TGF-β1 from RPE cells. The stimulatory effects of FXa on the expression of growth factors and secretion of VEGF were prevented by inhibition of the TGF-β activin receptor-like kinase, but not by the thrombin inhibitor hirudin. FXa induced phosphorylation of ERK1/2, p38, and Akt proteins.
  
  
  CONCLUSIONS
  FXa induces chemotaxis of RPE cells, as well as expression and release of angiogenic growth factors from RPE cells, including VEGF. The effects of FXa on the expression and secretion of VEGF are mediated by autocrine/paracrine TGF-β signaling.
authors.affiliation: Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany. hollbm@medizin.uni-leipzig.de
authors.forename: Margrit
authors.initials: M
authors.lastname: Hollborn
authors.forename: Leon
authors.initials: L
authors.lastname: Kohen
authors.forename: Cornelia
authors.initials: C
authors.lastname: Werschnik
authors.forename: Lore
authors.initials: L
authors.lastname: Tietz
authors.forename: Peter
authors.initials: P
authors.lastname: Wiedemann
authors.forename: Andreas
authors.initials: A
authors.lastname: Bringmann
mesh_terms: D043925:Angiogenesis Inducing Agents / Q000378:metabolism*; D015153:Blotting, Western; D002413:Cations, Divalent / Q000494:pharmacology; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D015232:Dinoprostone / Q000494:pharmacology; D015951:Factor Xa / Q000235:genetics*; D016222:Fibroblast Growth Factor 2 / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000378:metabolism*; D044967:Serum / Q000502:physiology; D014019:Tissue Donors; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
chemical_list: D043925:Angiogenesis Inducing Agents; D002413:Cations, Divalent; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D010982:Platelet-Derived Growth Factor; D053773:Transforming Growth Factor beta1; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D004247:DNA; D015951:Factor Xa; D015232:Dinoprostone