New Insights on Non-Enzymatic Oxidation of Ganglioside GM1 Using Mass Spectrometry

Daniela Couto; Tânia Melo; Elisabete Maciel; Ana Campos; Eliana Alves; Sofia Guedes; M Rosário M Domingues; Pedro Domingues

doi:10.1007/s13361-016-1474-1

New Insights on Non-Enzymatic Oxidation of Ganglioside GM1 Using Mass Spectrometry

J Am Soc Mass Spectrom. 2016 Dec;27(12):1965-1978. doi: 10.1007/s13361-016-1474-1. Epub 2016 Aug 30.

Authors

Daniela Couto¹, Tânia Melo¹, Elisabete Maciel^{1

2}, Ana Campos¹, Eliana Alves¹, Sofia Guedes¹, M Rosário M Domingues¹, Pedro Domingues³

Affiliations

¹ Mass Spectrometry Center, Department of Chemistry and QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal.
² Department of Biology and CESAM, University of Aveiro, Campus Universitario de Santiago, 3810-193, Aveiro, Portugal.
³ Mass Spectrometry Center, Department of Chemistry and QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal. p.domingues@ua.pt.

PMID: 27576485
DOI: 10.1007/s13361-016-1474-1

Abstract

Gangliosides are acidic glycosphingolipids that are present in cell membranes and lipid raft domains, being particularly abundant in central nervous systems. They participate in modulating cell membrane properties, cell-cell recognition, cell regulation, and signaling. Disturbance in ganglioside metabolism has been correlated with the development of diseases, such as neurodegenerative diseases, and in inflammation. Both conditions are associated with an increased production of reactive oxidation species (ROS) that can induce changes in the structure of biomolecules, including lipids, leading to the loss or modification of their function. Oxidized phospholipids are usually involved in chronic diseases and inflammation. However, knowledge regarding oxidation of gangliosides is scarce. In order to evaluate the effect of ROS in gangliosides, an in vitro biomimetic model system was used to study the susceptibility of GM1 (Neu5Acα2-3(Galβ1-3GalNAcβ1-4)Galβ1-4Glcβ1Cer) to undergo oxidative modifications. Oxidation of GM1 under Fenton reaction conditions was monitored using high resolution electrospray ionization-mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Upon oxidation, GM1 underwent oxidative cleavages in the carbohydrate chain, leading to the formation of other gangliosides GM2 (GalNAcβ1-4Gal(Neu5Acα2-3)1-4Glcβ1Cer), GM3 (Neu5Acα2-3Galβ1-4Glcβ1Cer), asialo-GM1 (Galβ1-3GalNAcβ1-4Galβ1-4Glcβ1Cer), asialo-GM2 (GalNAcβ1-4Galβ1-4Glcβ1Cer), of the small glycolipids lactosylceramide (LacCer), glucosylceramide (GlcCer), and of ceramide (Cer). In addition, oxygenated GM1 and GM2 (as keto and hydroxy derivatives), glycans, oxidized glycans, and oxidized ceramides were also identified. Nonenzymatic oxidation of GM1 under oxidative stress contributes to the generation of other gangliosides that may participate in the imbalance of gangliosides metabolism in vivo, through uncontrolled enzymatic pathways and, consequently, play some role in neurodegenerative processes. Graphical Abstract ᅟ.

Keywords: Electrospray ionization; Fenton reaction; GM1; Inflammation; Neurodegenerative diseases; Reactive oxygen species.

Publication types

Research Support, Non-U.S. Gov't