Clinical studies suggest that diets rich in ω-3 polyunsaturated fatty acids (PUFAs) provide beneficial anti-inflammatory effects, in part through their conversion to bioactive metabolites. Here we report on the endogenous production of a previously unknown class of ω-3 PUFA–derived lipid metabolites that originate from the crosstalk between endocannabinoid and cytochrome P450 (CYP) epoxygenase metabolic pathways. The ω-3 endocannabinoid epoxides are derived from docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) to form epoxyeicosatetraenoic acid-ethanolamide (EEQ-EA) and epoxydocosapentaenoic acid-ethanolamide (EDP-EA), respectively. Both EEQ-EAs and EDP-EAs are endogenously present in rat brain and peripheral organs as determined via targeted lipidomics methods. These metabolites were directly produced by direct epoxygenation of the ω-3 endocannabinoids, docosahexanoyl ethanolamide (DHEA) and eicosapentaenoyl ethanolamide (EPEA) by activated BV-2 microglial cells, and by human CYP2J2. Neuroinflammation studies revealed that the terminal epoxides 17,18-EEQ-EA and 19,20-EDP-EA dose-dependently abated proinflammatory IL-6 cytokines while increasing anti-inflammatory IL-10 cytokines, in part through cannabinoid receptor-2 activation. Furthermore the ω-3 endocannabinoid epoxides 17,18-EEQ-EA and 19,20-EDP-EA exerted antiangiogenic effects in human microvascular endothelial cells (HMVEC) and vasodilatory actions on bovine coronary arteries and reciprocally regulated platelet aggregation in washed human platelets. Taken together, the ω-3 endocannabinoid epoxides’ physiological effects are mediated through both endocannabinoid and epoxyeicosanoid signaling pathways. In summary, the ω-3 endocannabinoid epoxides are found at concentrations comparable to those of other endocannabinoids and are expected to play critical roles during inflammation in vivo; thus their identification may aid in the development of therapeutics for neuroinflammatory and cerebrovascular diseases.

Cannabinoid receptor activation is involved in homeostatic regulation of the body. These receptors are activated by cannabinoids, that include the active constituents of Cannabis sativa as well as endocannabinoids (eCBs). The eCBs are endogenously synthesized from the omega-6 and omega-3 polyunsaturated fatty acids (PUFAs). The consumption of omega-3 fatty acids shifts the balance towards a higher proportion of omega-3 eCBs, whose physiological functions warrants further investigation. Herein, we review the discovery of omega-3 fatty acid derived eCBs that are generated from long chain omega-3 PUFAs - docosahexaenoyl ethanolamide (DHA-EA or synaptamide), docosahexanoyl-glycerol (DHG), eicosapentaenoyl ethanolamide (EPA-EA), eicosapentanoylglycerol (EPG). Furthermore, we outline the lesser known omega-3 eCB-like molecules that arise from the conjugation of the omega-3 fatty acids with neurotransmitters serotonin and dopamine - DHA-serotonin (DHA-5HT), EPA-serotonin (EPA-5HT), DHA-dopamine (DHA-DA) and EPA-dopamine (EPA-DA). Additionally, we describe the role of these omega-3 eCBs and their derivatives in different disease states such as pain, inflammation and cancer. Moreover, we detail the formation and potential physiological roles of the oxidative metabolites that arise from the metabolism of omega-3 eCBs by eicosanoid synthesizing enzymes - cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 epoxygenase (CYP450). In summary, we outline the novel findings regarding a growing class of signaling molecules, omega-3 eCBs, that can control the physiological and pathophysiological processes in the body.

Accumulating studies have linked inflammation to tumor progression. Dietary omega-3 fatty acids, such as docosahexaenoic acid (DHA), have been shown to suppress tumor growth through their conversion to epoxide metabolites. Alternatively, DHA is converted enzymatically into docosahexaenoylethanolamide (DHEA), an endocannabinoid with antiproliferative activity. Recently, we reported a novel class of anti-inflammatory DHEA-epoxide derivative called epoxydocospentaenoic-ethanolamide (EDP-EA) that contain both ethanolamide and epoxide moieties. Herein, we study the antitumorigenic properties of EDP-EAs in an osteosarcoma (OS) model. First, we show ∼80% increase in EDP-EAs in metastatic versus normal lungs of mice. We found significant differences in the apoptotic and antimigratory potencies of the different EDP-EA regioisomers, which were partially mediated through cannabinoid receptor 1 (CB1). Next, we synthesized derivatives of the most pro-apoptotic regioisomer. These derivatives had reduced hydrolytic susceptibility to fatty acid amide hydrolase (FAAH) and increased CB1-selective binding. Collectively, we report a novel class of EDP-EAs that exhibit antiangiogenic, antitumorigenic, and antimigratory properties in OS.

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Objectives Omega-3 fatty acid derived endocannabinoids are metabolized by cytochrome P450s to form bioactive endocannabinoid epoxides that are anti-inflammatory Methods Lipidomics, LC-MS/MS, microglial cells culture, lipid synthesis, extractions, enzymology Results Cannabinoids are found in marijuana and also are produced naturally in the body from ω-3 and ω-6 fatty acids. Exocannabinoids in marijuana, are known to be responsible for some of its euphoric effects, but they also exhibit anti-inflammatory benefits. Our study revealed a cascade of enzymatic reactions that convert ω-3 fatty acids into anti-inflammatory endocannabinoid epoxides that act through the same receptors in the body as marijuana (PNAS 2017). Endocannabinoids are ligands for cannabinoid receptor 1 and 2 (CB1 and CB2). CB1 receptor agonists exhibit psychotropic properties while CB2 receptor agonists have anti-inflammatory effects. Consequently, there is a strong interest in the discovery of CB2 selective agonists to mitigate inflammatory pathologies. The work details the discovery and characterization of naturally occurring ω-3–derived endocannabinoid epoxides that are formed via enzymatic oxidation of ω-3 endocannabinoids by cytochrome P450 epoxygenases. These dual functional ω-3 endocannabinoid epoxides exhibit preference towards binding to CB2 receptor and are anti-inflammatory and vasodilatory and reciprocally modulate platelet aggregation. Some of the other regioisomers of ω-3 endocannabinoid epoxides are partial agonists of CB1 and stop tumor cell metastasis (J. Med. Chem 2018). By virtue of their physiological properties, they are expected to play important roles in neuroinflammation and pain. Conclusions This finding demonstrates how omega-3 fatty acids can produce some of the same medicinal qualities as marijuana, but without a psychotropic effect. In summary, the ω-3 endocannabinoid epoxides are found at concentrations comparable to those of other endocannabinoids and are expected to play critical roles during inflammation in vivo Funding Sources American Heart Association Scientist Development award, National Institute of Health (NIH) R01, NIH R03, USDA, National Multiple Sclerosis Society.