title: Profiling of Endo H-released serum N-glycans using CE-LIF and MALDI-TOF-MS--application to rheumatoid arthritis.
abstract: High-mannose and hybrid-type N-glycans are present in human serum glycoproteins in low abundance but have recently been described to play an important role in immune responses. It is therefore important to find a strategy to selectively analyze their structures in the context of health and disease in order to understand their impact on disease mechanisms. We report here the characterization of high-mannose and hybrid-type N-glycans in total human serum. To this end, N-glycans were released using Endo-β-N-acetylglucosaminidase H (Endo H) and analyzed by CE-LIF and MALDI-TOF-MS. We found that the high-mannose structures Man(5-9)GlcNAc(1) represented the majority of the pool. The monoglucosylated structure Glc(1)Man(9)GlcNAc(1) as well as four hybrid structures could be identified. Then, we compared the Endo H-released serum glycome of patients suffering from rheumatoid arthritis with healthy controls as mannose-binding lectin deficiency (MBL) and modulation of α-mannosidase activity were previously associated with this disease. Interestingly, we observed that both high-mannose and hybrid structures were fairly constant, suggesting that circulating MBL and α-mannosidase may not affect significantly the levels of serum glycoproteins carrying these glycans.
authors.affiliation: Glycodesign and Glycoanalytics, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité Medical University, Berlin, Germany.
authors.forename: Elena
authors.initials: E
authors.lastname: Frisch
authors.forename: Matthias
authors.initials: M
authors.lastname: Kaup
authors.forename: Karl
authors.initials: K
authors.lastname: Egerer
authors.forename: Andreas
authors.initials: A
authors.lastname: Weimann
authors.forename: Rudolf
authors.initials: R
authors.lastname: Tauber
authors.forename: Markus
authors.initials: M
authors.lastname: Berger
authors.forename: Véronique
authors.initials: V
authors.lastname: Blanchard
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood*; D001798:Blood Proteins / Q000737:chemistry / Q000378:metabolism; D002240:Carbohydrate Sequence; D016022:Case-Control Studies; D019075:Electrophoresis, Capillary / Q000379:methods*; D054794:Glycomics / Q000379:methods; D006023:Glycoproteins / Q000737:chemistry; D006801:Humans; D008358:Mannose / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D037601:Mannose-Binding Lectin / Q000737:chemistry; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000378:metabolism*; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry; D043323:alpha-Mannosidase / Q000737:chemistry
chemical_list: D001798:Blood Proteins; D006023:Glycoproteins; D037601:Mannose-Binding Lectin; D011134:Polysaccharides; D043323:alpha-Mannosidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008358:Mannose