title: Mass spectrometric approach for screening modifications of total serum N-glycome in human diseases: application to cirrhosis.
abstract: Congenital and acquired modifications of glycosylation in diseases are a rapidly growing field that demonstrates the importance of glycosylation in human biology. Unfortunately, in clinical biochemistry, very few tests are available to explore oligosaccharide metabolism on a large scale. Such an assay needs to be of high throughput, rapid, and preferentially noninvasive. In the present study, we describe a method to analyze qualitative variations of N-glycosylation of human serum proteins. The method is based on direct release of N-linked oligosaccharides from patient serum samples, a single-step purification, and a matrix-assisted laser desorption ionization time of flight mass spectrometric analysis. A complementary structural study of the released oligosaccharides was achieved by enzymatic digestions, linkage analysis, and electrospray ionization ion trap mass spectrometry (ESI-IT-MS) of the permethylated N-glycome. A total of 26 oligosaccharide structures were individualized, their presence in human serum being the result of the combination of the biosynthesis and catabolic pathways. Application of the protocol to the serum of patients with cirrhosis demonstrates the ability of this assay to identify acquired modifications of glycosylation. Furthermore, we have analyzed the N-glycans and showed the increase in bisecting N-acetylglucosamine residue, core fucosylation, and the presence of an important population of neutral oligosaccharides. The study of total serum N-glycome modifications is a preliminary for the discovery of new noninvasive diagnostic or prognostic biomarkers resulting from the variations of the N-glycan metabolism during diseases.
authors.affiliation: Unité Mixte de Recherche CNRS/USTL 8576, Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologis de Lille 1, 59655 Villeneuve d' Ascq, France.
authors.forename: Willy
authors.initials: W
authors.lastname: Morelle
authors.forename: Christophe
authors.initials: C
authors.lastname: Flahaut
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Michalski
authors.forename: Alexandre
authors.initials: A
authors.lastname: Louvet
authors.forename: Philippe
authors.initials: P
authors.lastname: Mathurin
authors.forename: André
authors.initials: A
authors.lastname: Klein
mesh_terms: D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins / Q000032:analysis*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005260:Female; D006031:Glycosylation; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood* / Q000175:diagnosis; D008297:Male; D008969:Molecular Sequence Data; D025942:Oligosaccharides, Branched-Chain / Q000097:blood*; D011237:Predictive Value of Tests; D046188:Protein Modification, Translational; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; D025942:Oligosaccharides, Branched-Chain