title: Lipidomics profile of a NAPE-PLD KO mouse provides evidence of a broader role of this enzyme in lipid metabolism in the brain.
abstract: A leading hypothesis of N-acyl ethanolamine (NAE) biosynthesis, including the endogenous cannabinoid anandamide (AEA), is that it depends on hydrolysis of N-acyl-phosphatidylethanolamines (NAPE) by a NAPE-specific phospholipase D (NAPE-PLD). Thus, deletion of NAPE-PLD should attenuate NAE levels. Previous analyses of two different NAPE-PLD knockout (KO) strains produced contradictory data on the importance of NAPE-PLD to AEA biosynthesis. Here, we examine this hypothesis with a strain of NAPE-PLD KO mice whose lipidome is uncharacterized. Using HPLC/MS/MS, over 70 lipids, including the AEA metabolite, N-arachidonoyl glycine (NAGly), the endocannabinoid 2-arachidonyl glycerol (2-AG) and prostaglandins (PGE(2) and PGF(2α)), and over 60 lipoamines were analyzed in 8 brain regions of KO and wild-type (WT) mice. Lipidomics analysis of this third NAPE-PLD KO strain shows a broad range of lipids that were differentially affected by lipid species and brain region. Importantly, all 6 NAEs measured were significantly reduced, though the magnitude of the effect varied by fatty acid saturation length and brain region. 2-AG levels were only impacted in the brainstem, where levels were significantly increased in KO mice. Correspondingly, levels of arachidonic acid were significantly decreased exclusively in brainstem. NAGly levels were significantly increased in 4 brain regions and levels of PGE(2) increased in 6 of 8 brain regions in KO mice. These data indicate that deletion of NAPE-PLD has far broader effects on the lipidome than previously recognized. Therefore, behavioral characteristics of suppressing NAPE-PLD activity may be due to a myriad of effects on lipids and not simply due to reduced AEA biosynthesis.
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA.
authors.forename: Emma
authors.initials: E
authors.lastname: Leishman
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA; Gill Center for Biomolecular Neuroscience, Indiana University, Bloomington, IN, USA.
authors.forename: Ken
authors.initials: K
authors.lastname: Mackie
authors.affiliation: Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, F-75205 Paris, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Luquet
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA. Electronic address: hbbradsh@indiana.edu.
authors.forename: Heather B
authors.initials: HB
authors.lastname: Bradshaw
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001095:Arachidonic Acids / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D001933:Brain Stem / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000378:metabolism; D015237:Dinoprost / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D063388:Endocannabinoids / Q000378:metabolism; D004983:Ethanolamines / Q000378:metabolism; D005989:Glycerides / Q000378:metabolism; D005998:Glycine / Q000031:analogs & derivatives / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000032:analysis*; D008636:Mesencephalon / Q000378:metabolism; D018345:Mice, Knockout; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010739:Phospholipase D / Q000235:genetics / Q000378:metabolism*; D053284:Polyunsaturated Alkamides / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D013788:Thalamus / Q000378:metabolism
chemical_list: D016718:Arachidonic Acid; D001095:Arachidonic Acids; D015237:Dinoprost; D015232:Dinoprostone; D063388:Endocannabinoids; D004983:Ethanolamines; D005989:Glycerides; D005998:Glycine; D008055:Lipids; D010714:Phosphatidylethanolamines; D010739:Phospholipase D; D053284:Polyunsaturated Alkamides; C022203:N-acylethanolamines; C465623:N-arachidonylglycine; C094503:glyceryl 2-arachidonate; C506062:Napepld protein, mouse; C078814:anandamide
keywords: Anandamide; Endogenous cannabinoid biosynthesis; Lipidomics; Lipoamine; NAPE-PLD