Resolvin D1 and its aspirin-triggered 17R epimer -: Stereochemical assignments, anti-inflammatory properties, and enzymatic inactivation

We recently uncovered two new families of potent docosahexaenoic acid-derived mediators, termed D series resolvins (Rv; resolution phase interaction products) and protectins. Here, we assign the stereochemistry of the conjugated double bonds and chirality of alcohols present in resolvin D1 (RvD1) and its aspirin-triggered 17R epimer (AT-RvDl) with compounds prepared by total organic synthesis. In addition, docosahexaenoic acid was converted by a single lipoxygenase in a "one-pot" reaction to RvD1 in vitro. The synthetic compounds matched the physical and biological properties of those enzymatically generated. RvD1 proved to be 7S,8R,17S-trihydroxy4Z,9E,11E,13Z,15E,19Z-docosahexaenoic acid, AT-RvD1 matched 7S,8R,17R-trihydroxy-4Z,9E,11E,13Z,15E,19Z-docosahexaenoic acid, and they both stopped transendothelial migration of human neutrophils (EC50 similar to 30 nm). In murine peritonitis in vivo, RvD1 and AT-RvD1 proved equipotent (at nanogram dosages), limiting polymorphonuclear leukocyte infiltration in a dose-dependent fashion. RvD1 was converted by eicosanoid oxidoreductase to novel 8-oxo- and 17-oxo-RvD1 that gave dramatically reduced bioactivity, whereas enzymatic conversion of AT-RvD1 was sharply reduced. These results establish the complete stereochemistry and actions of RvD1 and AT-RvDl as well as demonstrate the stereoselective basis for their enzymatic inactivation. RvD1 regulates human polymorphonuclear leukocyte transendothelial migration and is antiinflammatory. When its carbon 17S alcohol is enzymatically converted to 17-oxo-RvD1, it is essentially inactive, whereas the 17R alcohol configuration in its aspirin-triggered form (ATRvD1) resists rapid inactivation. These results maycontribute to the beneficial actions of aspirin and omega-3 fish oils in humans.