title: Glycophenotyping of osteoarthritic cartilage and chondrocytes by RT-qPCR, mass spectrometry, histochemistry with plant/human lectins and lectin localization with a glycoprotein.
abstract: BACKGROUND
  This study aimed to characterize the glycophenotype of osteoarthritic cartilage and human chondrocytes.
  
  
  METHODS
  Articular knee cartilage was obtained from nine osteoarthritis (OA) patients. mRNA levels for 27 glycosyltransferases were analyzed in OA chondrocytes using RT-qPCR. Additionally, N- and O-glycans were quantified using mass-spectrometry. Histologically, two cartilage areas with Mankin scores (MS) either ≤ 4 or ≥ 9 were selected from each patient representing areas of mild and severe OA, respectively. Tissue sections were stained with (1) a selected panel of plant lectins for probing into the OA glycophenotype, (2) the human lectins galectins-1 and -3, and (3) the glycoprotein asialofetuin (ASF) for visualizing β-galactoside-specific endogenous lectins.
  
  
  RESULTS
  We found that OA chondrocytes expressed oligomannosidic structures as well as non-, mono- and disialylated complex-type N-glycans, and core 2 O-glycans. Reflecting B4GALNT3 mRNA presence in OA chondrocytes, LacdiNAc-terminated structures were detected. Staining profiles for plant and human lectins were dependent on the grade of cartilage degeneration, and ASF-positive cells were observed in significantly higher rates in areas of severe degeneration.
  
  
  CONCLUSIONS
  In summary, distinct aspects of the glycome in OA cartilage are altered with progressing degeneration. In particular, the alterations measured by galectin-3 and the pan-galectin sensor ASF encourage detailed studies of galectin functionality in OA.
authors.forename: Stefan
authors.initials: S
authors.lastname: Toegel
authors.forename: Daniela
authors.initials: D
authors.lastname: Bieder
authors.forename: Sabine
authors.initials: S
authors.lastname: André
authors.forename: Friedrich
authors.initials: F
authors.lastname: Altmann
authors.forename: Sonja M
authors.initials: SM
authors.lastname: Walzer
authors.forename: Herbert
authors.initials: H
authors.lastname: Kaltner
authors.forename: Jochen G
authors.initials: JG
authors.lastname: Hofstaetter
authors.forename: Reinhard
authors.initials: R
authors.lastname: Windhager
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Gabius
mesh_terms: D001212:Asialoglycoproteins / Q000737:chemistry / Q000378:metabolism; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism* / Q000473:pathology; D060748:Fetuins / Q000737:chemistry / Q000378:metabolism; D037483:Galectin 1 / Q000378:metabolism; D037502:Galectin 3 / Q000378:metabolism; D015870:Gene Expression; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D037102:Lectins / Q000378:metabolism*; D013058:Mass Spectrometry; D015394:Molecular Structure; D017350:N-Acetylgalactosaminyltransferases / Q000235:genetics / Q000378:metabolism; D010003:Osteoarthritis / Q000235:genetics / Q000378:metabolism*; D037121:Plant Lectins / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001212:Asialoglycoproteins; D060748:Fetuins; D037483:Galectin 1; D037502:Galectin 3; D006023:Glycoproteins; D037102:Lectins; D037121:Plant Lectins; D011134:Polysaccharides; C017029:asialofetuin; D016695:Glycosyltransferases; D017350:N-Acetylgalactosaminyltransferases