Abstract
Proteinase-activated receptor 2 (PAR(2)) is a G-protein coupled receptor associated with many pathophysiological functions. To date, the development of PAR(2) antagonists has been limited. Here, we identify a number of novel peptide-mimetic PAR(2) antagonists and demonstrate inhibitory effects on PAR(2)-mediated intracellular signalling pathways and vascular responses.
The peptide-mimetic compound library based on the structures of PAR(2) agonist peptides were screened for inhibition of PAR(2)-induced calcium mobilisation in human keratinocytes. Representative compounds were further evaluated by radioligand binding and inhibition of NF kappa B transcriptional activity and IL-8 production. The vascular effects of the antagonists were assessed using in vitro and in vivo models.
Two compounds, K-12940 and K-14585, significantly reduced SLIGKV-induced Ca2+ mobilisation in primary human keratinocytes. Both K-12940 and K-14585 exhibited competitive inhibition for the binding of a high-affinity radiolabelled PAR(2)-ligand, [H-3]-2-furoyl-LIGRL-NH2, to human PAR(2) with K-i values of 1.94 and 0.627 mu M respectively. NF kappa B reporter activity and IL-8 production were also significantly reduced. Furthermore, relaxation of rat-isolated aorta induced by SLIGRL-NH2 was inhibited competitively by K-14585. K-14585 also significantly lowered plasma extravasation in the dorsal skin of guinea pigs and reduced salivation in mice.
K-12940 and K-14585 antagonized PAR(2) competitively, resulting in inhibition of PAR(2)-mediated signalling and physiological responses both in vitro and in vivo. These peptide-mimetic PAR(2) antagonists could be useful in evaluating PAR(2)-mediated biological events and might lead to a new generation of therapeutically useful antagonists.
Original language | English |
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Pages (from-to) | 361-371 |
Number of pages | 11 |
Journal | British Journal of Pharmacology |
Volume | 158 |
Issue number | 1 |
DOIs | |
Publication status | Published - Sep 2009 |
Keywords
- Proteinase-activated receptor 2 (PAR2
- antagonist
- Ca2+ mobilization
- keratinocytes
- radioligand-binding
- thrombin receptor
- smooth-muscle
- human keratinocytes
- nitric-oxide
- inflammation
- par-2
- secretion
- peptide
- cells
- mouse