Arita M, Bianchini F, Aliberti, et al. Stereochemical assignment, antiinflammatory properties, and receptor for the omega-3 lipid mediator resolvin E1. JEM, 2005;201(5):713-722.

The essential fatty acid eicosapentaenoic acid (EPA) present in fish oils displays beneficial effects in a range of human disorders associated with inflammation including cardiovascular disease.

Resolvin E1 (RvE1), a new bioactive oxygenated product of EPA, was identified in human plasma and prepared by total organic synthesis.

Results of bioaction and physical matching studies indicate that the complete structure of RvE1 is 5S,12R,18R-trihydroxy-6Z, 8E,10E,14Z,16E-EPA. At nanomolar levels, RvE1 dramatically reduced dermal inflammation, peritonitis, dendritic cell (DC) migration, and interleukin (IL) 12 production.
We screened receptors and identified one, denoted earlier as ChemR23, that mediates RvE1 signal to attenuate nuclear factor-B. Specific binding of RvE1 to this receptor was confirmed using synthetic [3H]-labeled RvE1. Treatment of DCs with small interference RNA specific for ChemR23 sharply reduced RvE1 regulation of IL-12.

These results demonstrate novel counterregulatory responses in inflammation initiated via RvE1 receptor activation that provide the first evidence for EPA-derived potent endogenous agonists of antiinflammation.

Chiang N, Serhan CN. Cell-cell interaction in the transcellular biosynthesis of novel omega-3-derived lipid mediators. Methods Mol Biol,2006;341:227-250.

Omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosa-hexaenoic acid (DHA) display beneficial actions in human diseases. The molecular basis for these actions remains of interest.

We recently identified novel mediators generated from omega-3 PUFA during cell-cell interactions that displayed potent anti-inflammatory and proresolving actions.

Compounds derived from EPA are designated resolvins of the E series (RvE1), and those biosynthesized from DHA are denoted resolvins of the D series (RvD) and docosatriene, such as protectin D1 (PD1), which belongs to the family of protectins. In addition, treatment using aspirin initiates a related epimeric series by triggering endogenous formation of the 17R-RvD series, denoted as aspirin-triggered (AT)-RvDs.

These compounds possess potent anti-inflammatory actions in vivo that essentially are equivalent to their counterpart generated without aspirin, namely the 17S-RvDs.

In this chapter, we provide an overview and detail protocols of the biosynthesis and bioactions of these newly uncovered pathways and products that include three distinct series: 18R-resolvins of the E series derived from EPA (i.e., RvE1); 17R-resolvins of the D series from DHA (AT-RvD1 through RvD4); and 17S-resolvins of the D series from DHA (RvD1 through RvD4).

Serhan CN, Gotlinger K, et al. Resolvins, docosatrienes & neuroprotectins, novel omega-3-derived mediators, & their aspirin-triggered endogenous epimers: an overview of their protective roles in catabasis. Prostag Lipid Mediat,2004;73 (3-4):155-172.

The molecular basis for the beneficial impact of essential omega-3 fatty acids is of considerable interest.

Recently, novel mediators generated from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that displayed potent bioactions were first identified in resolving inflammatory exudates [J. Exp. Med. 192 (2000) 1197; J. Exp. Med. 196 (2002) 1025] and in tissues enriched with DHA [J. Exp. Med. 196 (2002) 1025; J. Biol. Chem. 278 (2003) 14677].

The trivial names Resolvin (resolution phase interaction products) and docosatrienes were introduced for the bioactive compounds belonging to these novel series because they demonstrate potent anti-inflammatory and immunoregulatory actions.

The compounds derived from eicosapentaenoic acid carrying potent biological actions (i.e., 1-10 nM range) are designated E series, given their EPA precursor, and denoted as Resolvins of the E series (Resolvin E1 or RvE1), and those biosynthesized from the precursor docosahexaenoic acid are Resolvins of the D series (Resolvin D1 or RvD1).

Bioactive members from DHA with conjugated triene structures are docosatrienes (DT) that are immunoregulatory [J. Exp. Med. 196 (2002) 1025; J. Biol. Chem. 278 (2003) 14677], and neuroprotective [J. Biol. Chem., 278 (2003) 43807; Proc. Natl. Acad. Sci. U.S.A. [submitted for publication]] and are termed neuroprotectins.

The specific receptors for these novel bioactive products from omega-3 EPA and DHA are abbreviated Resolvin D receptors (i.e., ResoDR1), Resolvin E receptor (ResoER1; RER1), and neuroprotectin D receptors (NPDR), respectively, in recognition of their respective cognate ligands. Aspirin treatment impacts biosynthesis of these compounds and a related series by triggering endogenous formation of the 17R-D series Resolvins and docosatrienes. These novel epimers are denoted as aspirin-triggered (AT)-RvDs and -DTs, and possess potent anti-inflammatory actions in vivo essentially equivalent to their 17S series pathway products.

Here, we provide a syntomy overview of the formation and actions of these newly uncovered pathways and products as well as highlight their role(s) as endogenous protective mediators generated in anti-inflammation and catabasis.