Identification of novel membrane-associated prostaglandin E synthase-1 (mPGES-1) inhibitors with anti-influenza activities in vitro.

Influenza A virus (IAV) is a major public health concern that leads to high morbidity and mortality worldwide. Despite various vaccination programs and development of drugs targeting essential viral proteins, the emergence of drug-resistant variants has been frequently reported and the therapeutic options are limited. Because exaggerated inflammation is considered as an important factor in disease pathogenesis, immunomodulatory agents that effectively suppress cytokine responses are needed for the treatment of IAV infection. Membrane-associated prostaglandin E synthase-1 (mPGES-1) is an enzyme responsible for the production of prostaglandin E2 (PGE2) that is the best-characterized immune modulatory lipid in vitro and in vivo models of inflammation. In the present study, we tested the anti-influenza activities of mPGES-1 inhibitors, using a phenotype-based assay involving image analyses. Seven primary hits among 49 compounds targeting mPGES-1 exhibited anti-influenza activities against A/Puerto Rico/8/1934 (H1N1) in a dose-dependent manner. The most effective hit, MPO-0047, suppressed influenza-induced p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) activation. We also showed that mRNA levels of TNF-α, IL-8, CCL5/RANTES, and CXCL10/IP-10 were significantly reduced by the treatment of influenza-infected cells with MPO-0047. Exogenous PGE2 reversed the inhibitory effects of MPO-0047. Our results showed that this selective mPGES-1 inhibitor has anti-influenza effects by inhibiting PGE2 production, which suppresses the induction of pro-inflammatory genes. Taken together our data revealed that mPGES-1 inhibitor has the potential for further development as an influenza therapeutic agent.

Hit-to-lead optimization of phenylsulfonyl hydrazides for a potent suppressor of PGE2 production: Synthesis, biological activity, and molecular docking study.

Preliminary hit-to-lead optimization of a novel series of phenylsulfonyl hydrazide derivatives, which were derived from the high throughput screening hit compound 1 (IC50=5700nM against PGE2 production), for a potent suppressor of PGE2 production is described. Subsequent optimization led to the identification of the potent lead compound 8n with IC50 values of 4.5 and 6.9nM, respectively, against LPS-induced PGE2 production and NO production in RAW 264.7 macrophage cells. In addition, 8n was about 30- and >150-fold more potent against mPGES-1 enzyme in a cell-free assay (IC50=70nM) than MK-886 and hit compound 1, respectively. Molecular docking suggests that compound 8n could inhibit PGE2 production by blocking the PGH2 binding site of human mPGES-1 enzyme.

Synthesis, structure determination, and biological evaluation of phenylsulfonyl hydrazide derivatives as potential anti-inflammatory agents.

In our previous research, a novel series of phenylsulfonyl hydrazide derivatives were found to reduce LPS-induced PGE2 levels in RAW 264.7 macrophage cells via an inhibition of mPGES-1 enzyme. Recently, it was found that a regioisomeric mixture of phenylsulfonyl hydrazide was formed depending on the reaction conditions, which favor either of two regioisomers. One regioisomer corresponds to a kinetic product (7a-7c) and the other regioisomer corresponds to a thermodynamic product (8a-8c). Among them, the structure of kinetic product 7b was confirmed by measuring single X-ray crystallography. In vitro PGE2 assay studies showed that the kinetic product (7a and 7b; IC50=0.69 and 0.55µM against PGE2) is generally more potent than the thermodynamic product (8a and 8b; IC50=>10 and 0.79µM against PGE2). A molecular docking study also exhibited that the kinetic product (7a) has a higher MolDock Score (-147.4) than that of 8a (-142.4), which is consistent with the PGE2 assay results. A new potent phenylsulfonyl hydrazide (7d; IC50=0.06µM against PGE2) without affecting COX-1 and COX-2 enzyme activities was identified based on these overall results.