title: Glycosphingolipids and oxidative stress: evaluation of hydroxyl radical oxidation of galactosyl and lactosylceramides using mass spectrometry.
abstract: Galactosylceramide (GalCer) and lactosylceramide (LacCer) are structural and signaling lipids, playing important roles in signal transduction and cell adhesion. They are especially abundant in the nervous system and in important components of the myelin sheath. Although neurodegenerative disorders are associated with increased oxidative stress and lipid oxidation, the connection between oxidative stress and glycosphingolipid modification has been scarcely addressed. In this study, we aimed to characterize the structural changes caused by the hydroxyl radical to GalCer and LacCer molecular species using electrospray ionization mass spectrometry (ESI-MS and MS/MS) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS(n)). ESI-MS and LC-MS spectra of 24:1GalCer and 24:1LacCer after free radical oxidation showed the formation of new species, which were identified as keto, hydroxyl and hydroperoxy derivatives, arising from modification in the mono unsaturated fatty acyl chain. Formation of ceramide and oxidized ceramides was also observed as a result of 24:1GalCer and 24:1LacCer radical oxidation. 24:1GlcCer (glucosylceramide) was detected after LacCer oxidation, probably due to oxidative cleavage of lactosyl moiety. This study shows that glycosphingolipids are prone to radical induced oxidation, which can be one of the causes of the increased ceramides content and pro apoptotic events during oxidative conditions and neurodegeneration. This MS study will support the future identification of oxidized galactosyl- and lactosylceramide species in sphingolipidomic studies applied to biological samples related with oxidative conditions.
authors: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors: Daniela
authors: D
authors: Couto
authors: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors: Deolinda
authors: D
authors: Santinha
authors: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors: Tânia
authors: T
authors: Melo
authors: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; Laboratory of Signal Transduction, IBIMED, Health Sciences Department, University of Aveiro, Aveiro 3810-193, Portugal.
authors: Emanuel
authors: E
authors: Ferreira-Fernandes
authors: Chemistry Center - Vila Real (CQ-VR), Chemistry Department, School of Life and Environmental Sciences, University of Trás-os-Montes e Alto Douro, UTAD, 5001-801 Vila Real, Portugal.
authors: Romeu A
authors: RA
authors: Videira
authors: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors: Ana
authors: A
authors: Campos
authors: Laboratory of Signal Transduction, IBIMED, Health Sciences Department, University of Aveiro, Aveiro 3810-193, Portugal.
authors: Margarida
authors: M
authors: Fardilha
authors: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors: Pedro
authors: P
authors: Domingues
authors: Mass Spectrometry Centre, UI-QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: mrd@ua.pt.
authors: M Rosário M
authors: MR
authors: Domingues
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005699:Galactosylceramides / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007790:Lactosylceramides / Q000737:chemistry*; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D005699:Galactosylceramides; D007790:Lactosylceramides; D017665:Hydroxyl Radical
keywords: Fenton reaction; Galactosylceramide; Glycolipids; Lipidomics; Oxidation; ROS