title: Endocannabinoid content in fetal bovine sera - unexpected effects on mononuclear cells and osteoclastogenesis.
abstract: The major endocannabinoids (ECs) arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG) and related N-ethanolamines act as full and partial agonists at CB(1), CB(2), GPR55, PPAR and TRPV1 receptors to various degrees. These receptors are also expressed in immune cells like monocytes/macrophages where they regulate different cellular processes. In this study, potentially bioactive lipids in fetal bovine sera (FBS) were quantified by GC/MS. We found that several commercial FBS contain ECs and bioactive amounts of 2-AG (250-700 nM). We show that residual 2-AG from FBS can activate primary macrophages and increase migration and RANKL-stimulated osteoclastogenesis. Furthermore, 2-AG high-content sera specifically upregulated LPS-stimulated IL-6 expression in U937 cells. Polymyxin B beads may be used to selectively and efficiently remove 2-AG from sera, but not arachidonic acid and N-ethanolamines. In conclusion, 2-AG in cell culture media may significantly influence cellular experiments. CD14+ mononuclear cells which strongly express surface CB receptors may be particularly sensitive towards residual 2-AG from FBS. Therefore, the EC content in culture media should be controlled in biological experiments involving monocytes/macrophages.
authors.affiliation: Institute of Biochemistry and Molecular Medicine (IBMM), Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland.
authors.forename: Janine
authors.initials: J
authors.lastname: Marazzi
authors.forename: Jonas
authors.initials: J
authors.lastname: Kleyer
authors.forename: Juan Manuel Viveros
authors.initials: JM
authors.lastname: Paredes
authors.forename: Jürg
authors.initials: J
authors.lastname: Gertsch
mesh_terms: D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism / Q000494:pharmacology; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism* / Q000494:pharmacology*; D002417:Cattle; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D063388:Endocannabinoids; D005312:Fetal Blood / Q000737:chemistry*; D005434:Flow Cytometry; D008401:Gas Chromatography-Mass Spectrometry; D005989:Glycerides / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D008055:Lipids / Q000032:analysis / Q000302:isolation & purification; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009000:Monocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053245:RANK Ligand / Q000494:pharmacology; D043882:Receptors, Cannabinoid / Q000378:metabolism; D020298:U937 Cells
chemical_list: D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D005989:Glycerides; D015850:Interleukin-6; D008055:Lipids; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D053245:RANK Ligand; D043882:Receptors, Cannabinoid; C094503:glyceryl 2-arachidonate