title: Markers of monocyte activation revealed by lipidomic profiling of arachidonic acid-containing phospholipids.
abstract: Stimulated human monocytes undergo an intense trafficking of arachidonic acid (AA) among glycerophospholipidclasses. Using HPLC coupled to electrospray ionization mass spectrometry, we have characterized changes in the levels of AA-containing phospholipid species in human monocytes. In resting cells, AA was found esterified into various molecular species of phosphatidylinositol (PI), choline glycerophospholipids (PCs), and ethanolamine glycerophospholipids (PEs). All major AA-containing PC and PI molecular species decreased in zymosan-stimulated cells; however, no PE molecular species was found to decrease. In contrast, the levels of three AA-containing species increased in zymosan-activated cells compared with resting cells: 1,2-diarachidonyl-glycero-3-phosphoinositol [PI(20:4/20:4)]; 1,2-diarachidonyl-glycero-3-phosphocholine [PC(20:4/20:4)]; and 1-palmitoleoyl-2-arachidonyl-glycero-3-phosphoethanolamine [PE(16:1/20:4)]. PI(20:4/20:4) and PC(20:4/20:4), but not PE(16:1/20:4), also significantly increased when platelet-activating factor or PMA were used instead of zymosan to stimulate the monocytes. Analysis of the pathways involved in the synthesis of these three lipids suggest that PI(20:4/20:4) and PC(20:4/20:4) were produced in a deacylation/reacylation pathway via acyl-CoA synthetase-dependent reactions, whereas PE(16:1/20:4) was generated via a CoA-independent transacylation reaction. Collectively, our results define the increases in PI(20:4/20:4) and PC(20:4/20:4) as lipid metabolic markers of human monocyte activation and establish lipidomics as a powerful tool for cell typing under various experimental conditions.
authors.affiliation: Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Valladolid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Balgoma
authors.forename: Alma M
authors.initials: AM
authors.lastname: Astudillo
authors.forename: Gema
authors.initials: G
authors.lastname: Pérez-Chacón
authors.forename: Olimpio
authors.initials: O
authors.lastname: Montero
authors.forename: María A
authors.initials: MA
authors.lastname: Balboa
authors.forename: Jesús
authors.initials: J
authors.lastname: Balsinde
mesh_terms: D016718:Arachidonic Acid / Q000737:chemistry* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D009000:Monocytes / Q000737:chemistry* / Q000378:metabolism*; D010743:Phospholipids / Q000737:chemistry* / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D010743:Phospholipids; D016718:Arachidonic Acid