title: The Endocannabinoid Metabolite Prostaglandin E2(PGE2)-Glycerol Inhibits Human Neutrophil Functions: Involvement of Its Hydrolysis into PGE2and EP Receptors.
abstract: The endocannabinoids 2-arachidonoyl-glycerol andN-arachidonoyl-ethanolamine mediate an array of pro- and anti-inflammatory effects. These effects are related, in part, to their metabolism by eicosanoid biosynthetic enzymes. For example,N-arachidonoyl-ethanolamine and 2-arachidonoyl-glycerol can be metabolized by cyclooxygenase-2 into PG-ethanolamide (PG-EA) and PG-glycerol (PG-G), respectively. Although PGE2is a recognized suppressor of neutrophil functions, the impact of cyclooxygenase-derived endocannabinoids such as PGE2-EA or PGE2-G on neutrophils is unknown. This study's aim was to define the effects of these mediators on neutrophil functions and the underlying cellular mechanisms involved. We show that PGE2-G, but not PGE2-EA, inhibits leukotriene B4biosynthesis, superoxide production, migration, and antimicrobial peptide release. The effects of PGE2-G were prevented by EP1/EP2receptor antagonist AH-6809 but not the EP4antagonist ONO-AE2-227. The effects of PGE2-G required its hydrolysis into PGE2, were not observed with the non-hydrolyzable PGE2-serinol amide, and were completely prevented by methyl-arachidonoyl-fluorophosphate and palmostatin B, and partially prevented by JZL184 and WWL113. Although we could detect six of the documented PG-G hydrolases in neutrophils by quantitative PCR, only ABHD12 and ABHD16A were detected by immunoblot. Our pharmacological data, combined with our protein expression data, did not allow us to pinpoint one PGE2-G lipase, and rather support the involvement of an uncharacterized lipase and/or of multiple hydrolases. In conclusion, we show that PGE2-G inhibits human neutrophil functions through its hydrolysis into PGE2, and by activating the EP2receptor. This also indicates that neutrophils could regulate inflammation by altering the balance between PG-G and PG levels in vivo.
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Médecine, Faculté de Médecine, Université Laval, Quebec City, Quebec G1V 4G5, Canada; and.
authors.forename: Caroline
authors.initials: C
authors.lastname: Turcotte
authors.affiliation: Department of Pharmacology, University of Colorado Denver, Aurora, CO 80045.
authors.forename: Simona
authors.initials: S
authors.lastname: Zarini
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Médecine, Faculté de Médecine, Université Laval, Quebec City, Quebec G1V 4G5, Canada; and.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Jean
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Médecine, Faculté de Médecine, Université Laval, Quebec City, Quebec G1V 4G5, Canada; and.
authors.forename: Cyril
authors.initials: C
authors.lastname: Martin
authors.affiliation: Department of Pharmacology, University of Colorado Denver, Aurora, CO 80045.
authors.forename: Robert C
authors.identifier: 0000-0002-9430-6515
authors.initials: RC
authors.lastname: Murphy
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Médecine, Faculté de Médecine, Université Laval, Quebec City, Quebec G1V 4G5, Canada; and.
authors.forename: David
authors.identifier: 0000-0002-8935-6657
authors.initials: D
authors.lastname: Marsolais
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Médecine, Faculté de Médecine, Université Laval, Quebec City, Quebec G1V 4G5, Canada; and.
authors.forename: Michel
authors.initials: M
authors.lastname: Laviolette
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Médecine, Faculté de Médecine, Université Laval, Quebec City, Quebec G1V 4G5, Canada; and.
authors.forename: Marie-Renée
authors.initials: MR
authors.lastname: Blanchet
authors.affiliation: Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Département de Médecine, Faculté de Médecine, Université Laval, Quebec City, Quebec G1V 4G5, Canada; and Nicolas.Flamand@criucpq.ulaval.ca.
authors.forename: Nicolas
authors.identifier: 0000-0001-5944-7200
authors.initials: N
authors.lastname: Flamand
mesh_terms: D002853:Chromatography, Liquid; D015232:Dinoprostone / Q000276:immunology / Q000378:metabolism*; D063388:Endocannabinoids / Q000276:immunology / Q000378:metabolism*; D005990:Glycerol; D006801:Humans; D015151:Immunoblotting; D013058:Mass Spectrometry; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D058307:Receptors, Prostaglandin E, EP2 Subtype / Q000276:immunology / Q000378:metabolism*
chemical_list: D063388:Endocannabinoids; D058307:Receptors, Prostaglandin E, EP2 Subtype; D015232:Dinoprostone; D005990:Glycerol