title: Alteration of N-Glycan Profiles in Diabetic Retinopathy.
abstract: OBJECTIVE
  To investigate the alteration of vitreal N-glycans in patients with proliferative diabetic retinopathy (PDR).
  
  
  METHODS
  Plasma and vitreous samples were collected from 17 patients (10 females and 7 males) with PDR (PDR group) and 17 nondiabetic patients (8 females and 9 males) with epiretinal membrane (ERM) and idiopathic macular hole (MH) (non-diabetes mellitus [DM] group). Profiles of N-glycans were analyzed by a glycoblotting-based high-throughput protocol that we recently developed. Human retinal microvascular endothelial cells (HRMECs) were cultivated with culture media containing either low glucose (5 mM) or high glucose (25 mM), and expression levels of sialyltransferases were analyzed by real-time PCR and ELISA.
  
  
  RESULTS
  Amount of N-glycans in the vitreous fluid of the PDR group was significantly higher than that of the non-DM group (495.5 ± 37.4 vs. 142.7 ± 30.8 pmol/100 μg protein, P < 0.005), whereas there was no significant difference in the plasma samples between the PDR and the non-DM group. In addition, profile analysis showed that N-glycans with sialic acids increased in the vitreous of the PDR group (328.4 ± 25.8 pmol/100 μg protein) compared to the non-DM group (92.1 ± 21.2 pmol/100 μg protein, P < 0.0005). Expression levels of sialyltransferases ST3GAL1 and ST3GAL4 were upregulated in the HRMECs after high-glucose stimulation. Consistent with the real-time PCR data, high-glucose stimulation elevated the protein levels of ST3GAL1 (117.4 ± 14.9 pg/mg, P < 0.01) and ST3GAL4 (6.1 ± 0.9 pg/mg, P < 0.05) in the HRMECs compared with the cells cultured with low-glucose culture media (ST3GAL1, 64.4 ± 5.8 pg/mg; ST3GAL4, 3.8 ± 0.3 pg/mg).
  
  
  CONCLUSIONS
  Our data demonstrate distinct changes in the N-glycan profile and an increase in sialylated N-glycans in eyes with PDR.
authors.affiliation: Laboratory of Ocular Cell Biology and Visual Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan 2Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan 3Field of Drug Discovery Research, Faculty.
authors.forename: Saori
authors.initials: S
authors.lastname: Inafuku
authors.affiliation: Laboratory of Ocular Cell Biology and Visual Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan 2Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Noda
authors.affiliation: Field of Drug Discovery Research, Faculty of Advanced Life Science, Graduate School of Life Science, Hokkaido University, Sapporo, Japan 4Medicinal Chemistry Pharmaceuticals Co. Ltd., Sapporo, Japan.
authors.forename: Maho
authors.initials: M
authors.lastname: Amano
authors.affiliation: Field of Drug Discovery Research, Faculty of Advanced Life Science, Graduate School of Life Science, Hokkaido University, Sapporo, Japan.
authors.forename: Tetsu
authors.initials: T
authors.lastname: Ohashi
authors.affiliation: Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Yoshizawa
authors.affiliation: Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Saito
authors.affiliation: Laboratory of Ocular Cell Biology and Visual Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan 2Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Murata
authors.affiliation: Laboratory of Ocular Cell Biology and Visual Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan 2Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kanda
authors.affiliation: Field of Drug Discovery Research, Faculty of Advanced Life Science, Graduate School of Life Science, Hokkaido University, Sapporo, Japan 4Medicinal Chemistry Pharmaceuticals Co. Ltd., Sapporo, Japan.
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Nishimura
authors.affiliation: Laboratory of Ocular Cell Biology and Visual Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan 2Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Ishida
mesh_terms: D000368:Aged; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics*; D002478:Cells, Cultured; D003930:Diabetic Retinopathy / Q000235:genetics* / Q000378:metabolism / Q000601:surgery; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011134:Polysaccharides / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D012799:Sialyltransferases / Q000096:biosynthesis / Q000235:genetics*; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism* / Q000473:pathology; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
chemical_list: D015703:Antigens, CD; D011134:Polysaccharides; D012333:RNA, Messenger; D012799:Sialyltransferases; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase; C093493:ST6GAL1 protein, human; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase; C000722087:ST3GAL1 protein, human