title: Endothelin-1 (ET-1) stimulates carboxy terminal Smad2 phosphorylation in vascular endothelial cells by a mechanism dependent on ET receptors and de novo protein synthesis.
abstract: OBJECTIVE
  G protein-coupled receptor (GPCR) agonists through their receptors can transactivate protein tyrosine kinase receptors such as epidermal growth factor receptor and serine/threonine kinase receptors most notably transforming growth factor (TGF)-β receptor (TβRI). This signalling mechanism represents a major expansion in the cellular outcomes attributable to GPCR signalling. This study addressed the role and mechanisms involved in GPCR agonist, endothelin-1 (ET-1)-mediated transactivation of the TβRI in bovine aortic endothelial cells (BAECs).
  
  
  METHODS
  The in-vitro model used BAECs. Signalling intermediate phospho-Smad2 in the carboxy terminal was detected and quantified by Western blotting.
  
  
  RESULTS
  ET-1 treatment of BAECs resulted in a time and concentration-dependent increase in pSmad2C. Peak phosphorylation was evident with 100 nm treatment of ET-1 at 4-6 h. TβRI antagonist, SB431542 inhibited ET-1-mediated pSmad2C. In the presence of bosentan, a mixed ETAand ETBreceptor antagonist ET-1-mediated pSmad2C levels were inhibited. The ET-mediated pSmad2C was blocked by the protein synthesis inhibitor, cycloheximide.
  
  
  CONCLUSIONS
  In BAECs, ET-1 via the ETB receptor is involved in transactivation of the TβRI. The transactivation-dependent response is dependent upon de novo protein synthesis.
authors.affiliation: Student Research Committee, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Narges
authors.initials: N
authors.lastname: Sharifat
authors.affiliation: Hyperlipidemia Research Center, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Ghorban
authors.initials: G
authors.lastname: Mohammad Zadeh
authors.affiliation: Cellular and Molecular Research Center, Ahvaz Jundishapour University of Medical Sciences, Ahvaz, Iran.
authors.forename: Mohammad-Ali
authors.initials: MA
authors.lastname: Ghaffari
authors.affiliation: Student Research Committee, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Parisa
authors.initials: P
authors.lastname: Dayati
authors.affiliation: Pharmacy Australia Centre of Excellence, The University of Queensland, Woolloongabba, Qld, Australia.
authors.forename: Danielle
authors.initials: D
authors.lastname: Kamato
authors.affiliation: Pharmacy Australia Centre of Excellence, The University of Queensland, Woolloongabba, Qld, Australia.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Little
authors.affiliation: Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Atherosclerosis Research Center, Ahvaz, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Babaahmadi-Rezaei
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D000077300:Bosentan; D002417:Cattle; D003513:Cycloheximide / Q000494:pharmacology; D004149:Dioxoles / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D065128:Endothelin Receptor Antagonists / Q000494:pharmacology; D019332:Endothelin-1 / Q000378:metabolism* / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D010766:Phosphorylation; D014176:Protein Biosynthesis / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D044023:Receptor, Endothelin B / Q000378:metabolism*; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D015398:Signal Transduction; D051899:Smad2 Protein / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; D004149:Dioxoles; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D011500:Protein Synthesis Inhibitors; D044023:Receptor, Endothelin B; D018125:Receptors, Transforming Growth Factor beta; D051899:Smad2 Protein; D013449:Sulfonamides; D016212:Transforming Growth Factor beta; D003513:Cycloheximide; D000077300:Bosentan
keywords: atherosclerosis; endothelin-1; phosphorylated Smad2; transactivation; transforming growth factor-β