RT Journal Article
SR Electronic
T1 A Cytochrome P450-Derived Epoxygenated Metabolite of Anandamide Is a Potent Cannabinoid Receptor 2-Selective Agonist
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 965
OP 972
DO 10.1124/mol.108.053439
VO 75
IS 4
A1 Natasha T. Snider
A1 James A. Nast
A1 Laura A. Tesmer
A1 Paul F. Hollenberg
YR 2009
UL http://molpharm.aspetjournals.org/content/75/4/965.abstract
AB Oxidation of the endocannabinoid anandamide by cytochrome P450 (P450) enzymes has the potential to affect signaling pathways within the endocannabinoid system and pharmacological responses to novel drug candidates targeting this system. We previously reported that the human cytochromes P450 2D6, 3A4, and 4F2 are high-affinity, high-turnover anandamide oxygenases in vitro, forming the novel metabolites hydroxyeicosatetraenoic acid ethanolamides and epoxyeicosatrienoic acid ethanolamides. The objective of this study was to investigate the possible biological significance of these metabolic pathways. We report that the 5,6-epoxide of anandamide, 5,6-epoxyeicosatrienoic acid ethanolamide (5,6-EET-EA), is a potent and selective cannabinoid receptor 2 (CB2) agonist. The Ki values for the binding of 5,6-EET-EA to membranes from Chinese hamster ovary (CHO) cells expressing either recombinant human CB1 or CB2 receptor were 11.4 μM and 8.9 nM, respectively. In addition, 5,6-EET-EA inhibited the forskolin-stimulated accumulation of cAMP in CHO cells stably expressing the CB2 receptor (IC50 = 9.8 ± 1.3 nM). Within the central nervous system, the CB2 receptor is expressed on activated microglia and is a potential therapeutic target for neuroinflammation. BV-2 microglial cells stimulated with low doses of interferon-γ exhibited an increased capacity for converting anandamide to 5,6-EET-EA, which correlated with increased protein expression of microglial P450 4F and 3A isoforms. Finally, we demonstrate that 5,6-EET-EA is more stable than anandamide in mouse brain homogenates and is primarily metabolized by epoxide hydrolase. Combined, our results suggest that epoxidation of anandamide by P450s to form 5,6-EET-EA represents an endocannabinoid bioactivation pathway in the context of immune cell function. The American Society for Pharmacology and Experimental Therapeutics