AC 264613

AC 264613 is a potent agonist of PAR2 with pEC50 value of 7.5 and potencies range from 30 to 100 nM [1, 2].

Protease-activated receptor 2 (PAR2) also known as coagulation factor II (thrombin) receptor-like 1 (F2RL1) or G-protein coupled receptor 11 (GPR11) is expressed in vascular tissue and highly vascular organs and involves in the vascular tone regulation. It has been shown that PAR2 plays a pivotal role in vessel inflammation and wound healing processes [2].

AC 264613 is a selective PAR2 agonist and has no effect on other PARs. When tested with HEK 293 T cells (PAR2 wild type) and KNRK cells (transfected with human PAR2 receptors) for stimulates PI hydrolysis and Ca2+ mobilization assays, AC 264613 showed effect with pEC50 value of 6.9 and 7.0,respectively [1]. Using QuickChange Mutagenesis manner, NIH 3T3 cells were made with ECL2 mutations in Q233E, E232R, E232R/Q233R, F240S, and F240S/S37P receptors and AC 264613 treatment PAR2 F240S receptors were constitutively expressed in multiple functional endpoints while had no effect on E232 and Q233 mutaions [2].

In male Sprague-Dawley rat model with acute thermal nociception and edema in paw induced by SLIGRL-NH2 or trypsin, intrapaw administration of AC 264613 induced hind paw edema and thermal hyperalgesia at the doses as low as 30 ng and showed dose-dependent pronociceptive effects [1].

References:
[1].  Gardell, L.R., et al., Identification and characterization of novel small-molecule protease-activated receptor 2 agonists. J Pharmacol Exp Ther, 2008. 327(3): p. 799-808.
[2].   Ma, J.N. and E.S. Burstein, The protease activated receptor 2 (PAR2) polymorphic variant F240S constitutively activates PAR2 receptors and potentiates responses to small-molecule PAR2 agonists. J Pharmacol Exp Ther, 2013. 347(3): p. 697-704.

A protease-activated receptor 2 agonist (AC-264613) suppresses interferon regulatory factor 5 and decreases interleukin-12p40 production by lipopolysaccharide-stimulated macrophages: Role of p53.[Pubmed:26833899]

Cell Biol Int. 2016 Jun;40(6):629-41.

The transcription factor interferon regulatory factor 5 (IRF5) has a key role in the production of interleukin (IL)-12 by macrophages. IRF5 is also a central mediator of toll-like receptor signaling and is a direct target of p53. Activation of protease-activated receptor 2 (PAR-2) upregulates p53 and suppresses apoptosis. This study investigated the influence of human neutrophil elastase (HNE) and PAR-2 agonists on expression of IRF5 and IL-12p40 by macrophages stimulated with lipopolysaccharide. Granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent macrophages showed upregulation of IRF5 expression, while HNE reduced expression of p53 and IRF5 in a concentration-dependent manner. HNE also caused a concentration-dependent decrease of IRF5 in macrophages transfected with small interfering RNA to silence p53, while silencing of beta-arrestin 2 blunted the reduction of p53 or IRF5 by HNE. Incubation of macrophages with a PAR-2 agonist, AC-264613, caused a decrease of IRF5 expression and also significantly reduced p53 protein expression. HNE upregulated the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6) and caused transactivation of TLR4, while AC-264613 did not promote TLR4 transactivation. In conclusion, the PAR-2 agonist AC-264613 attenuated IRF5-associated IL-12p40 production by macrophages.

Identification and characterization of novel small-molecule protease-activated receptor 2 agonists.[Pubmed:18768780]

J Pharmacol Exp Ther. 2008 Dec;327(3):799-808.

We report the first small-molecule protease-activated receptor (PAR) 2 agonists, AC-55541 [N-[[1-(3-bromo-phenyl)-eth-(E)-ylidene-hydrazinocarbonyl]-(4-oxo-3,4-dihydro-pht halazin-1-yl)-methyl]-benzamide] and AC-264613 [2-oxo-4-phenylpyrrolidine-3-carboxylic acid [1-(3-bromo-phenyl)-(E/Z)-ethylidene]-hydrazide], each representing a distinct chemical series. AC-55541 and AC-264613 each activated PAR2 signaling in cellular proliferation assays, phosphatidylinositol hydrolysis assays, and Ca(2+) mobilization assays, with potencies ranging from 200 to 1000 nM for AC-55541 and 30 to 100 nM for AC-264613. In comparison, the PAR2-activating peptide 2-furoyl-LIGRLO-NH(2) had similar potency, whereas SLIGRL-NH(2) was 30 to 300 times less potent. Neither AC-55541 nor AC-264613 had activity at any of the other PAR receptor subtypes, nor did they have any significant affinity for over 30 other molecular targets involved in nociception. Visualization of EYFP-tagged PAR2 receptors showed that each compound stimulated internalization of PAR2 receptors. AC-55541 and AC-264613 were well absorbed when administered intraperitoneally to rats, each reaching micromolar peak plasma concentrations. AC-55541 and AC-264613 were each stable to metabolism by liver microsomes and maintained sustained exposure in rats, with elimination half-lives of 6.1 and 2.5 h, respectively. Intrapaw administration of AC-55541 or AC-264613 elicited robust and persistent thermal hyperalgesia and edema. Coadministration of either a tachykinin 1 (neurokinin 1) receptor antagonist or a transient receptor potential vanilloid (TRPV) 1 antagonist completely blocked these effects. Systemic administration of either AC-55541 or AC-264613 produced a similar degree of hyperalgesia as was observed when the compounds were administered locally. These compounds represent novel small-molecule PAR2 agonists that will be useful in probing the physiological functions of PAR2 receptors.

Discovery of potent and selective small-molecule PAR-2 agonists.[Pubmed:18720984]

J Med Chem. 2008 Sep 25;51(18):5490-3.

Proteinase activated receptor-2 plays a crucial role in a wide variety of conditions with a strong inflammatory component. We present the discovery and characterization of two structurally different, potent, selective, and metabolically stable small-molecule PAR-2 agonists. These ligands may be useful as pharmacological tools for elucidating the complex physiological role of the PAR-2 receptors as well as for the development of PAR-2 antagonists.