論文

© 2017 American Chemical Society. Synthesis of 14S,21R- and 14S,21S-dihydroxy-DHA (diHDHA) among the four possible stereoisomers of 14,21-diHDHA was studied. Methyl (R)-lactate (>97% ee), selected as a C20-C22 fragment (DHA numbering), was converted to the C17-C22 phosphonium salt, which was subjected to a Wittig reaction with racemic C16-aldehyde of the C12-C16 part with the TMS and TBS-oxy groups at C12 and C14, yielding the C12-C22 derivative with 14R/S and 21R chirality. Kinetic resolution using Sharpless asymmetric epoxidation of the TBS-deprotected allylic alcohol with l-(+)-DIPT/Ti(O-i-Pr) 4 afforded 14S-epoxy alcohol and 14R-allylic alcohol with >99% diastereomeric excess (de) for both. The CN group was introduced to the epoxy alcohol by reaction with Et 2 AlCN. The 14R-allylic alcohol was also converted to the nitrile via Mitsunobu inversion. Reduction of the nitrile with DIBAL afforded the key aldehyde corresponding to the C11-C22 moiety. The Wittig reaction of this aldehyde with a phosphonium salt of the remaining C1-C10 part followed by functional group manipulation gave 14S,21R-diHDHA. Similarly, ethyl (S)-lactate (>99% ee) was converted to 14S,21S-diHDHA. The chiral LC-UV-MS/MS analysis demonstrated that each of these two 14,21-diHDHAs synthesized using the presented total organic synthesis was highly stereoselective and identical to the macrophage-produced counterpart.

© 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd. Background: Asthma is characterized by airway inflammation and obstruction with eosinophil infiltration into the airway. Arachidonic acid, an omega-6 fatty acid, is metabolized into cysteinyl leukotriene with pro-inflammatory properties for allergic inflammation, whereas the omega-3 fatty acid eicosapentaenoic acid (EPA) and its downstream metabolites are known to have anti-inflammatory effects. In this study, we investigated the mechanism underlying the counter-regulatory roles of EPA in inflamed lungs. Methods: Male C57BL6 mice were sensitized and challenged by ovalbumin (OVA). After EPA treatment, we evaluated the cell count of Bronchoalveolar lavage fluid (BALF), mRNA expressions in the lungs by q-PCR, and the amounts of lipid mediators by liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based lipidomics. We investigated the effect of the metabolite of EPA by in vivo and in vitro studies. Results: Eicosapentaenoic acid treatment reduced the accumulation of eosinophils in the airway and decreased mRNA expression of selected inflammatory mediators in the lung. Lipidomics clarified the metabolomic profile in the lungs. Among EPA-derived metabolites, 12-hydroxy-17,18-epoxyeicosatetraenoic acid (12-OH-17,18-EpETE) was identified as one of the major biosynthesized molecules; the production of this molecule was amplified by EPA administration and allergic inflammation. Intravenous administration of 12-OH-17,18-EpETE attenuated airway eosinophilic inflammation through downregulation of C-C chemokine motif 11 (CCL11) mRNA expression in the lungs. In vitro, this molecule also inhibited the release of CCL11 from human airway epithelial cells stimulated with interleukin-4. Conclusion: These results demonstrated that EPA alleviated airway eosinophilic inflammation through its conversion into bioactive metabolites. Additionally, our results suggest that 12-OH-17,18-EpETE is a potential therapeutic target for the management of asthma.

Pseudomonas aeruginosa lung infection is a main cause of disability and mortality worldwide. Acute inflammation and its timely resolution are crucial for ensuring bacterial clearance and limiting tissue damage. Here, we investigated protective actions of resolvin (Rv) D1 in lung infection induced by the RP73 clinical strain of P. aeruginosa. RvD1 significantly diminished bacterial growth and neutrophil infiltration during acute pneumonia caused by RP73. Inoculum of RP73, immobilized in agar beads, resulted in persistent lung infection up to 21 days, leading to a non resolving inflammation reminiscent of human pathology. RvD1 significantly reduced bacterial titer, leukocyte infiltration, and lung tissue damage. In murine lung macrophages sorted during P. aeruginosa chronic infection, RvD1 regulated the expression of Toll-like receptors, downstream genes, and microRNA (miR)-21 and 155, resulting in reduced inflammatory signaling. In vitro, RvD1 enhanced phagocytosis of P. aeruginosa by neutrophils and macrophages, recapitulating its in vivo actions. These results unveil protective functions and mechanisms of action of RvD1 in acute and chronic P. aeruginosa pneumonia, providing evidence for its potent pro-resolution and tissue protective properties on airway mucosal tissue during infection.