title: Upregulation of proteinase-activated receptor-2 and increased response to trypsin in endothelial cells after exposure to oxidative stress in rat aortas.
abstract: OBJECTIVE
  The effects of oxidative stress on the vascular responsiveness to the agonists of proteinase-activated receptors (PARs) were investigated.
  
  
  METHODS
  Serum-free incubation was utilized to impose oxidative stress to isolated rat aortas. Spontaneously hypertensive rats (SHR) were investigated as a model of in vivo oxidative stress.
  
  
  RESULTS
  Thrombin, trypsin, PAR₁-activating peptide (PAR₁-AP), PAR₂-AP and PAR₄-AP induced little or no effect in the aortas of female Wistar-Kyoto rats (WKY). Serum-free incubation induced endothelium-dependent relaxant responses to PAR₂ agonists, but not PAR₁ or PAR₄ agonists, in a manner sensitive to diphenyleneiodonium or ascorbic acid. In male aortas, trypsin and PAR₂-AP induced a transient endothelium-dependent relaxation without serum-free incubation. The acetylcholine-induced endothelium-dependent relaxation and the sodium nitroprusside-induced endothelium-independent relaxation remained unchanged. Immunoblot analyses revealed the upregulation of PAR₂ in endothelial cells, which was abolished by either diphenyleneiodonium or ascorbic acid. Aortas of female SHR expressed a higher level of PAR₂ than WKY and responded to trypsin without serum-free incubation. Treatment with ascorbic acid attenuated the trypsin-induced relaxation and the PAR₂ expression in SHR.
  
  
  CONCLUSIONS
  This study provides the first evidence that oxidative stress upregulates PAR₂ in endothelial cells, thereby enhancing the endothelium-dependent relaxant response to PAR₂ agonists in rat aortas.
authors.affiliation: Division of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan.
authors.forename: Murasaki
authors.initials: M
authors.lastname: Aman
authors.forename: Mayumi
authors.initials: M
authors.lastname: Hirano
authors.forename: Hideo
authors.initials: H
authors.lastname: Kanaide
authors.forename: Katsuya
authors.initials: K
authors.lastname: Hirano
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001011:Aorta / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology; D016895:Culture Media, Serum-Free; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D005260:Female; D006973:Hypertension / Q000201:enzymology* / Q000503:physiopathology; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D044464:Receptor, PAR-2 / Q000819:agonists / Q000378:metabolism*; D013997:Time Factors; D046509:Tissue Culture Techniques; D014357:Trypsin / Q000378:metabolism*; D015854:Up-Regulation; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D016895:Culture Media, Serum-Free; D009842:Oligopeptides; D044464:Receptor, PAR-2; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; C112356:seryl-leucyl-isoleucyl-glycyl--arginyl-leucinamide; D014357:Trypsin