Anti-inflammatory properties of a dual PPARgamma/alpha agonist muraglitazar in in vitro and in vivo models.

INTRODUCTION: Peroxisome proliferator-activated receptor (PPAR) agonists are widely used drugs in the treatment of diabetes and dyslipidemia. In addition to their metabolic effects, PPAR isoforms PPARα and PPARγ are also involved in the regulation of immune responses and inflammation. In the present study, we investigated the effects of a dual PPARγ/α agonist muraglitazar on inflammatory gene expression in activated macrophages and on carrageenan-induced inflammation in the mouse. METHODS: J774 murine macrophages were activated by lipopolysaccharide (LPS) and treated with dual PPARγ/α agonist muraglitazar, PPARγ agonist GW1929 or PPARα agonist fenofibrate. The effects of PPAR agonists on cytokine production and the activation of inducible nitric oxide synthase (iNOS) pathway were investigated by ELISA, Griess method, Western blotting and quantitative RT-PCR. Nuclear translocation, DNA-binding activity and reporter gene assays were used to assess the activity of nuclear factor kappa B (NF-kB) transcription factor. Carrageenan-induced paw oedema was used as an in vivo model of acute inflammation. RESULTS: Muraglitazar as well as PPARγ agonist GW1929 and PPARα agonist fenofibrate inhibited LPS-induced iNOS expression and NO production in activated macrophages in a dose-dependent manner. Inhibition of iNOS expression by muraglitazar included both transcriptional and post-transcriptional components; the former being shared by GW1929 and the latter by fenofibrate. All tested PPAR agonists also inhibited IL-6 production, while TNFα production was reduced by muraglitazar and GW1929, but not by fenofibrate. Interestingly, the anti-inflammatory properties of muraglitazar were also translated in vivo. This was evidenced by the finding that muraglitazar inhibited carrageenan-induced paw inflammation in a dose-dependent manner in mice as did iNOS inhibitor L-NIL and anti-inflammatory steroid dexamethasone. CONCLUSIONS: These results show that muraglitazar has anti-inflammatory properties both in vitro and in vivo and these effects reflect the agonistic action through both PPARα and PPARγ.

Synthesis and anti-inflammatory effects of a series of novel 7-hydroxycoumarin derivatives.

A number of 7-hydroxycoumarins have been synthesised by Pechmann cyclisation using differently substituted resorcinols employing perchloric acid as the condensing agent. All the compounds have been characterised by analytical and spectroscopic methods. The anti-inflammatory properties were tested with LPS-induced inflammation in J774 macrophages. Expression of iNOS and COX-2 was determined by Western blot, NO by nitrite assay and IL-6 by ELISA analyses. Fifteen of the tested 7-hydroxycoumarins also inhibited IL-6 production but none of them had any major inhibitory effect on COX-2 expression.