title: Evaluation of a combined glycomics and glycoproteomics approach for studying the major glycoproteins present in biofluids: Application to cerebrospinal fluid.
abstract: BACKGROUND
  Glycosylation is one of the most complex types of post-translational modifications of proteins. The alteration of glycans bound to proteins from cerebrospinal fluid (CSF) in relation to disorders of the central nervous system is a highly relevant subject, but only few studies have focused on the glycosylation of CSF proteins.
  
  
  METHODS
  Reproducible profiles of CSF N-glycans were first obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry after permethylation. Tryptic glycopeptides from CSF proteins were also enriched by hydrophilic interaction, and the resulting extracts divided into two equal aliquots. A first aliquot was enzymatically deglycosylated and analyzed by nano-liquid chromatography/tandem mass spectrometry while the second one, containing intact enriched glycopeptides, was directly analyzed. Site-specific data were obtained by combining the data from these three experiments.
  
  
  RESULTS
  We describe the development of a versatile approach for obtaining site-specific information on the N-glycosylation of CSF glycoproteins. Under these conditions, 124 N-glycopeptides representing 55 N-glycosites from 36 glycoproteins were tentatively identified. Special emphasis was placed on the analysis of glycoproteins/glycopeptides bearing 'brain-type' N-glycans, representing potential biologically relevant structures in the field of neurodegenerative disorders. Using our workflow, only a few proteins were shown to carry such particular glycan motifs.
  
  
  CONCLUSIONS
  We developed an approach combining N-glycomics and N-glycoproteomics and underline its usefulness to study the site-specific glycosylation of major human CSF proteins. The final rather long-term objective is to combine these data with those from other omics approaches to delve deeper into the understanding of particular neurological disorders.
authors.affiliation: CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, 91191, Gif-sur-Yvette, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Goyallon
authors.affiliation: CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, 91191, Gif-sur-Yvette, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Cholet
authors.affiliation: Bruker Daltonique, 77447, Marne-la-Vallée, France.
authors.forename: Manuel
authors.initials: M
authors.lastname: Chapelle
authors.affiliation: CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, 91191, Gif-sur-Yvette, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Junot
authors.affiliation: CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, 91191, Gif-sur-Yvette, France.
authors.forename: François
authors.initials: F
authors.lastname: Fenaille
mesh_terms: D000595:Amino Acid Sequence; D002853:Chromatography, Liquid / Q000379:methods*; D054794:Glycomics / Q000379:methods*; D006023:Glycoproteins / Q000134:cerebrospinal fluid* / Q000737:chemistry; D006031:Glycosylation; D006801:Humans; D008969:Molecular Sequence Data; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D006023:Glycoproteins