title: Neuropeptide Y expression, localization and cellular transducing effects in HUVEC.
abstract: BACKGROUND
  NPY (neuropeptide Y) may have an effect on the properties of vascular endothelial cells such as pro-angiogenic effects and potentiation of noradrenaline-induced vasoconstriction. In HUVEC (human umbilical-vein endothelial cells), immunoreactive neuropeptide Y has been detected, but NPY synthesis, storage and secretion have not been studied. The aim of the present study was to establish NPY expression, storage and cellular transducing effects in HUVEC.
  
  
  RESULTS
  HUVEC contain 0.19 fmol of NPY/microg of protein and 0.46 fmol of pro-NPY/microg of protein, as measured by ELISA. RT (reverse transcriptase)-PCR confirmed the expression of NPY in HUVEC. Immunofluorescence revealed the presence of NPY in small punctate structures, with a fluorescence pattern different from that observed for von Willebrand factor, indicating distinct storage compartments. Double labelling for NPY and Rab3A demonstrated similar granular patterns, with at least partial co-localization. Electron microscopy showed NPY immunoreactivity in vesicle-like cytoplasmic structures, of a fine fibrillar texture, as well as in mitochondria and in the nucleus. A similar general distribution pattern was also obtained for Rab3A. Y1 and Y2 receptors were expressed in HUVEC as assessed by RT-PCR, and they were functional since NPY induced a 42 nM intracellular calcium increase within 100 s, representing 22% of the histamine-induced response. In contrast with histamine, NPY did not induce acute von Willebrand factor secretion.
  
  
  CONCLUSIONS
  HUVEC produce, store and respond to NPY, suggesting an autocrine regulatory role for NPY in the endothelium.
authors.affiliation: Division d'Hypertension et de Médecine Vasculaire, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
authors.forename: Antonio P
authors.initials: AP
authors.lastname: Silva
authors.forename: Jocelyne E
authors.initials: JE
authors.lastname: Kaufmann
authors.forename: Cécile
authors.initials: C
authors.lastname: Vivancos
authors.forename: Stanislav
authors.initials: S
authors.lastname: Fakan
authors.forename: Claudia
authors.initials: C
authors.lastname: Cavadas
authors.forename: Phillip
authors.initials: P
authors.lastname: Shaw
authors.forename: Hans R
authors.initials: HR
authors.lastname: Brunner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Vischer
authors.forename: Eric
authors.initials: E
authors.lastname: Grouzmann
mesh_terms: D002118:Calcium / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D017979:Gold Colloid / Q000494:pharmacology; D006632:Histamine / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007700:Kinetics; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000378:metabolism; D009478:Neuropeptide Y / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014471:Umbilical Veins / Q000166:cytology*; D020826:rab3A GTP-Binding Protein / Q000378:metabolism; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D016895:Culture Media, Serum-Free; D017979:Gold Colloid; D009478:Neuropeptide Y; D012333:RNA, Messenger; D014841:von Willebrand Factor; D006632:Histamine; D000242:Cyclic AMP; D020826:rab3A GTP-Binding Protein; D002118:Calcium