PT - JOURNAL ARTICLE AU - Xu, Daigen AU - Rowland, Steven E. AU - Clark, Patsy AU - Giroux, André AU - Côté, Bernard AU - Guiral, Sébastien AU - Salem, Myriam AU - Ducharme, Yves AU - Friesen, Richard W. AU - Méthot, Nathalie AU - Mancini, Joseph AU - Audoly, Laurent AU - Riendeau, Denis TI - MF63 [2-(6-Chloro-1<em>H</em>-phenanthro[9,10-<em>d</em>]imidazol-2-yl)-isophthalonitrile], a Selective Microsomal Prostaglandin E Synthase-1 Inhibitor, Relieves Pyresis and Pain in Preclinical Models of Inflammation AID - 10.1124/jpet.108.138776 DP - 2008 Sep 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 754--763 VI - 326 IP - 3 4099 - http://jpet.aspetjournals.org/content/326/3/754.short 4100 - http://jpet.aspetjournals.org/content/326/3/754.full SO - J Pharmacol Exp Ther2008 Sep 01; 326 AB - Microsomal prostaglandin E synthase-1 (mPGES-1) is a terminal prostaglandin E2 (PGE2) synthase in the cyclooxygenase pathway. Inhibitors of mPGES-1 may block PGE2 production and relieve inflammatory symptoms. To test the hypothesis, we evaluated the antipyretic and analgesic properties of a novel and selective mPGES-1 inhibitor, MF63 [2-(6-chloro-1H-phenanthro-[9,10-d]imidazol-2-yl)isophthalonitrile], in animal models of inflammation. MF63 potently inhibited the human mPGES-1 enzyme (IC50 = 1.3 nM), with a high degree (&gt;1000-fold) of selectivity over other prostanoid synthases. In rodent species, MF63 strongly inhibited guinea pig mPGES-1 (IC50 = 0.9 nM) but not the mouse or rat enzyme. When tested in the guinea pig and a knock-in (KI) mouse expressing human mPGES-1, the compound selectively suppressed the synthesis of PGE2, but not other prostaglandins inhibitable by nonsteroidal anti-inflammatory drugs (NSAIDs), yet retained NSAID-like efficacy at inhibiting lipopolysaccharide-induced pyresis, hyperalgesia, and iodoacetate-induced osteoarthritic pain. In addition, MF63 did not cause NSAID-like gastrointestinal toxic effects, such as mucosal erosions or leakage in the KI mice or nonhuman primates, although it markedly inhibited PGE2 synthesis in the KI mouse stomach. Our data demonstrate that mPGES-1 inhibition leads to effective relief of both pyresis and inflammatory pain in preclinical models of inflammation and may be a useful approach for treating inflammatory diseases. The American Society for Pharmacology and Experimental Therapeutics