title: Vascular endothelial growth factor stimulates rat cholangiocyte proliferation via an autocrine mechanism.
abstract: OBJECTIVE
  Vascular endothelial growth factor (VEGF) is secreted by several epithelia and modulates cellular functions by autocrine and paracrine mechanisms. The role of VEGF in cholangiocyte pathophysiology is unknown. We evaluated the role of VEGF in the regulation of cholangiocyte proliferation in rats that underwent bile duct ligation.
  
  
  METHODS
  The expression of VEGF-A and VEGF-C and their receptors in cholangiocytes from normal and BDL rats was evaluated. Normal or BDL rats were treated with recombinant-VEGF-A or recombinant-VEGF-C or anti-VEGF antibodies, and proliferation of cholangiocytes was evaluated in situ by morphometry and in vitro by proliferating cell nuclear antigen immunoblots and MTS assay. In vitro, normal rat cholangiocyte cultures were stimulated with r-VEGF-A or r-VEGF-C and proliferation and signal transduction were evaluated.
  
  
  RESULTS
  We found that (1) cholangiocytes express messenger RNA and protein for VEGF-A, VEGF-C, VEGF receptor 2 (VEGFR-2), and VEGF receptor 3 (VEGFR-3) and secrete VEGF; (2) secretion of VEGF and expression of VEGFR-2 and VEGFR-3 increases in BDL cholangiocytes; (3) blocking VEGF in vivo by anti-VEGF-A or anti-VEGF-C antibodies decreases cholangiocyte proliferation; (4) the in vivo administration of r-VEGF-A or r-VEGF-C induces cholangiocyte proliferation in normal rats; and (5) in vitro, VEGF-A increases normal rat cholangiocyte culture proliferation by activation of inositol 1,4,5-triphosphate/Ca2+/protein kinase C alpha and phosphorylation of Src/ERK1/2.
  
  
  CONCLUSIONS
  Cholangiocytes secrete VEGF and express VEGFR-2 and VEGFR-3, all of which are amplified in BDL cholangiocytes. VEGF induces cholangiocyte proliferation by activation of inositol 1,4,5-triphosphate/[Ca2+]i/protein kinase C alpha and phosphorylation of Src/ERK1/2. VEGF mediates the adaptive proliferative response of cholangiocytes to cholestasis.
authors.affiliation: Division of Anatomy, University "La Sapienza," Rome, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Gaudio
authors.forename: Barbara
authors.initials: B
authors.lastname: Barbaro
authors.forename: Domenico
authors.initials: D
authors.lastname: Alvaro
authors.forename: Shannon
authors.initials: S
authors.lastname: Glaser
authors.forename: Heather
authors.initials: H
authors.lastname: Francis
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ueno
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Meininger
authors.forename: Antonio
authors.initials: A
authors.lastname: Franchitto
authors.forename: Paolo
authors.initials: P
authors.lastname: Onori
authors.forename: Marco
authors.initials: M
authors.lastname: Marzioni
authors.forename: Silvia
authors.initials: S
authors.lastname: Taffetani
authors.forename: Giammarco
authors.initials: G
authors.lastname: Fava
authors.forename: George
authors.initials: G
authors.lastname: Stoica
authors.forename: Julie
authors.initials: J
authors.lastname: Venter
authors.forename: Ramona
authors.initials: R
authors.lastname: Reichenbach
authors.forename: Sharon
authors.initials: S
authors.lastname: De Morrow
authors.forename: Ryun
authors.initials: R
authors.lastname: Summers
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Alpini
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D019898:Autocrine Communication / Q000502:physiology*; D001652:Bile Ducts / Q000166:cytology* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D022781:Hepatocytes / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008026:Ligation; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D051571:Protein Kinase C-alpha / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D011994:Recombinant Proteins / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000097:blood / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D042582:Vascular Endothelial Growth Factor C / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000906:Antibodies; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A; D042582:Vascular Endothelial Growth Factor C; C467498:vascular endothelial growth factor A, rat; D015544:Inositol 1,4,5-Trisphosphate; D040301:Vascular Endothelial Growth Factor Receptor-2; D040321:Vascular Endothelial Growth Factor Receptor-3; D019061:src-Family Kinases; D051571:Protein Kinase C-alpha; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium