title: Detection of phosphatidylserine with a modified polar head group in human keratinocytes exposed to the radical generator AAPH.
abstract: Phosphatidylserine (PS) is preferentially located in the inner leaflet of the cell membrane, and translocation of PS oxidized in fatty acyl chains to the outside of membrane has been reported as signaling to macrophage receptors to clear apoptotic cells. It was recently shown that PS can be oxidized in serine moiety of polar head-group. In the present work, a targeted lipidomic approach was applied to detecting OxPS modified at the polar head-group in keratinocytes that were exposed to the radical generator AAPH. Glycerophosphoacetic acid derivatives (GPAA) were found to be the major oxidation products of OxPS modified at the polar head-group during oxidation induced by AAPH-generated radicals, similarly to previous observations for the oxidation induced by OH radical. The neutral loss scan of 58Da and a novel precursor ion scan of m/z 137.1 (HOPO3CH2COOH) allowed the recognition of GPAA derivatives in the total lipid extracts obtained from HaCaT cells treated with AAPH. The positive identification of serine head group oxidation products in cells under controlled oxidative conditions opens new perspectives and justifies further studies in other cellular environments in order to understand fully the role of PS polar head-group oxidation in cell homeostasis and disease.
authors.affiliation: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Maciel
authors.affiliation: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Bruno M
authors.initials: BM
authors.lastname: Neves
authors.affiliation: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Deolinda
authors.initials: D
authors.lastname: Santinha
authors.affiliation: School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
authors.forename: Ana
authors.initials: A
authors.lastname: Reis
authors.affiliation: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Domingues
authors.affiliation: Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal; Center for Neuroscience and Cell Biology (CNC), University of Coimbra, 3004-517 Coimbra, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Teresa Cruz
authors.affiliation: School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Pitt
authors.affiliation: School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
authors.forename: Corinne M
authors.initials: CM
authors.lastname: Spickett
authors.affiliation: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: mrd@ua.pt.
authors.forename: M Rosário M
authors.initials: MR
authors.lastname: Domingues
mesh_terms: D000578:Amidines / Q000494:pharmacology*; D002460:Cell Line; D006801:Humans; D015603:Keratinocytes / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology*; D010718:Phosphatidylserines / Q000737:chemistry / Q000378:metabolism*; D012694:Serine / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000578:Amidines; D016877:Oxidants; D010718:Phosphatidylserines; D012694:Serine; C046728:2,2'-azobis(2-amidinopropane)
keywords: AAPH; Keratinocytes; Mass spectrometry; Oxidative stress; Phosphatidylserine; Shotgun lipidomic