Omega-3 Fatty Acid Derived Neuroactive Lipids - Docosahexaenoyl-Glycine and Its Epoxide Metabolites are Multifunctional Lipid Mediators

Lipid mediators derived from ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) support neurological health in part through their oxidative and non-oxidative transformation into a diverse array of bioactive molecules. Among these are lipidated neurotransmitters, formed via conjugation of neurotransmitters with fatty acids such as arachidonic acid (AA) or docosahexaenoic acid (DHA). Previous studies links these lipidated neurotransmitters to beneficial outcomes in neurological diseases. Here, we focus on two such endogenous lipidated neurotransmitters, arachidonoyl glycine (NA-Gly) and docosahexaenoyl glycine (DHA-Gly) and demonstrate their further biotransformation by cytochrome P450 enzymes into epoxidized metabolites. These metabolites are structurally multifunctional, combining both epoxide and glycine moieties. In lipopolysaccharide-stimulated microglial cells, we observe increased formation of NA-Gly and DHA-Gly, correlating with their anti-inflammatory effects. Functionally, these lipidated glycines are selective and act as inverse agonists of G protein-coupled receptor 55 (GPR55) and selectively potentiate transient receptor potential vanilloid 4 (TRPV4), but not TRPV1 or TRPM3 channels. Together, our findings identify NA-Gly, DHA-Gly, and their epoxide derivatives as multifunctional lipid mediators with anti-inflammatory properties and selective receptor modulation, positioning them as potential therapeutic leads in neuroinflammation and reinforce the critical side role of glycine in brain function. Significance: Lipidated neurotransmitters derived from omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) contribute to neurological health through their conversion into a diverse array of bioactive signaling molecules. In this study, we study docosahexaenoyl glycine (DHA-Gly) and demonstrate their further enzymatic transformation by cytochrome P450 epoxygenases into epoxidized derivatives. These structurally distinct metabolites exhibit anti-inflammatory activity in microglial cells and interact with GPR55 and TRPV4, but not TRPV1 or TRPM3. Our findings highlight a new class of multifunctional lipid mediators with therapeutic potential for targeting neuroinflammation and related neurological disorders.