title: Dual effect of the novel peptide antagonist K-14585 on proteinase-activated receptor-2-mediated signalling.
abstract: OBJECTIVE
  Here we have examined the effects of the novel peptide antagonist N-[1-(2,6-dichlorophenyl)methyl]-3-(1-pyrrolidinylmethyl)-1H-indol-5-yl]aminocarbonyl]-glycinyl-L-lysinyl-L-phenylalanyl-N-benzhydrylamide (K-14585) on proteinase-activated receptor (PAR)(2)-mediated intracellular signalling events.
  
  
  METHODS
  Using NCTC2544 cells expressing PAR(2), we assessed the effects of K-14585 on PAR(2)-mediated [(3)H] inositol phosphate accumulation, MAP kinase activation, p65 NFkappaB phosphorylation and DNA binding and IL-8 production.
  
  
  RESULTS
  Pretreatment with K-14585 (5 microM) inhibited [(3)H] inositol phosphate levels stimulated by PAR(2)-activating peptide Ser-Leu-Ile-Gly-Lys-Val (SLIGKV-OH) in PAR(2)-expressing NCTC2544 cells. K-14585 pretreatment did not influence PAR(2)-mediated extracellular regulated kinase activation but inhibited p38 MAP kinase phosphorylation. At a higher concentration (30 microM), K-14585 alone stimulated p38 MAP kinase activation. These effects were replicated in EAhy926 cells, endogenously expressing PAR(2), but not in parental or PAR(4)-expressing NCTC2544 cells, suggesting these effects were PAR(2)-dependent. SLIGKV-mediated stimulation of p38 MAP kinase phosphorylation was substantially reduced by the G(q/11) inhibitor YM-254890, without affecting K-14585-mediated phosphorylation. Pretreatment with K-14585 inhibited PAR(2)-mediated p65 NFkappaB phosphorylation and NFkappaB-DNA binding. K-14585 (30 microM) alone stimulated comparable NFkappaB reporter activity to SLIGKV-OH. K-14585 inhibited SLIGKV-stimulated IL-8 production, but given alone increased IL-8. While SLIGKV-induced IL-8 formation was reduced by both SB203580 and YM-254890, the response to K-14585 was sensitive to SB203580 but not YM-254890.
  
  
  CONCLUSIONS
  These data reveal that K-14585 has a duality of action functioning both as an antagonist and agonist due to either partial agonist actions or possible agonist-directed signalling. The data also suggest two modes of p38 MAP kinase activation emanating from PAR(2), one G(q/11)-dependent and the other G(q/11)-independent.
authors.affiliation: Division of Physiology & Pharmacology, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
authors.forename: Fui Goon
authors.initials: FG
authors.lastname: Goh
authors.forename: Pei Yuen
authors.initials: PY
authors.lastname: Ng
authors.forename: Mary
authors.initials: M
authors.lastname: Nilsson
authors.forename: Toru
authors.initials: T
authors.lastname: Kanke
authors.forename: Robin
authors.initials: R
authors.lastname: Plevin
mesh_terms: D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000494:pharmacology; D010766:Phosphorylation; D011725:Pyridines / Q000494:pharmacology; D044464:Receptor, PAR-2 / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D007093:Imidazoles; C547641:K-14585; D009842:Oligopeptides; D010456:Peptides, Cyclic; D011725:Pyridines; D044464:Receptor, PAR-2; C475455:YM-254890; C109968:seryl-leucyl-isoleucyl--glycyl-lysyl-valine; D048051:p38 Mitogen-Activated Protein Kinases; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; C093642:SB 203580