Lipoxins (LXs) are endogenously generated
eicosanoids with potent bio-actions consistent with attenuation of
inflammation. The costly synthesis and metabolic instability of LXs may limit their therapeutic potential. Here we report the synthesis and characterization of novel
imidazole-/
oxazole-containing synthetic-LX-mimetics (sLXms). The key steps of asymmetric synthesis of putative sLXms include a Suzuki reaction and an asymmetric
ketone reduction. The effect of the novel compounds on inflammatory responses was assessed using a human monocyte cell line stably expressing a
Nuclear Factor Kappa B (NFkB) reporter gene, by investigating downstream
cytokine secretion. The potential interaction of the
imidazoles/
oxazoles with the molecular target of LXs, i.e.
G-protein coupled receptor (GPCR)
Formyl Peptide Receptor 2 (ALX/FPR2) was investigated using a cell system where ALX/FPR2 is coupled to the Gαq subunit and receptor interaction determined by mobilisation of intracellular
calcium. In vivo anti-inflammatory effects were assessed using a murine
zymosan-induced
peritonitis model. Overall, structure-activity relationship (SAR) studies demonstrated that the (R)-epimer of 6C-dimethyl-imidazole (1R)-11 was the most potent and efficient
anti-inflammatory agent, among the ten compounds tested. This molecule significantly attenuated LPS-induced NFkB activity, reduced the release of several pro-inflammatory
cytokines and inhibited
peritonitis-associated neutrophil infiltration in vivo. The underlying mechanism for those actions appeared to be through FPR2 activation. These data support the therapeutic potential of
imidazole-containing sLXms in the context of novel inflammatory regulators.