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Toegel, S; Pabst, M; Wu, SQ; Grass, J; Goldring, MB; Chiari, C; Kolb, A; Altmann, F; Viernstein, H; Unger, FM.
(2010): Phenotype-related differential alpha-2,6- or alpha-2,3-sialylation of glycoprotein N-glycans in human chondrocytes.
Osteoarthritis Cartilage. 2010; 18(2):240-248 FullText FullText_BOKU

Abstract:
Objective Sialic acids frequently occur at the terminal positions of glycoprotein N-glycans present at chondrocyte surfaces or in the cartilage matrix Sialic acids are transferred to glycoproteins in either alpha-2,3 or alpha-2,6 linkage by specific sialyltransferases (SiaTs) and can potentially affect cell functions and cell-matrix interactions The present study aimed to assess the relationship between the expression of the human chondrocyte phenotype and the sialylation of chondrocyte glycoprotein N-glycans. Methods The transcription of 5 SiaT was quantified using real-time Reverse transcription polymerase chain reaction (RT-PCR) assays N-glycan analysis was performed using LC-ESI-MS Primary human chondrocytes were cultured in monolayer or alginate beads and compared to the chondrocyte cell lines C-28/I2 and SW1353. In addition, effects of interteukin-1 beta (IL-1 beta) or tumour necrosis factor-alpha (TNF-alpha) on primary cells were assessed Results Primary human chondrocytes predominantly express alpha-2,6-specific SiaTs and accordingly, alpha-2,6-linked sialic acid residues in glycoprotein N-glycans In contrast, the preponderance of alpha-2,3-linked sialyl residues and, correspondingly, reduced levels of alpha-2,6-specific SiaTs are associated with the altered chondrocyte phenotype of C-28/12 and SW1353 cells Importantly, a considerable shift towards alpha-2,3-linked sialic acids and alpha-2,3-specific SiaT mRNA levels occurred in primary chondrocytes treated with IL-1 beta or tumour necrosis factor-alpha (TNF-alpha) Conclusion The expression of the differentiated chondrocyte phenotype is linked to the ratio of alpha-2,6- to alpha-2,3-linked sialic acids in chondrocyte glycoprotein N-glycans A shift towards altered sialylation might contribute to impaired cell-matrix interactions in disease conditions (C) 2009 Osteoarthntis Research Society International Published by Elsevier Ltd All rights reserved
Authors BOKU Wien:
Altmann Friedrich
Grass Josephine
Pabst Martin

Find related publications in this database (Keywords)
Chondrocytes
Extracellular matrix
Cell-matrix interaction
Glycoproteins
Sialic acids
Sialyltransferases
Differentiation
Phenotype


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