TY - JOUR
T1 - Phenotype-related differential α-2,6- or α-2,3-sialylation of glycoprotein N-glycans in human chondrocytes
AU - Toegel, S.
AU - Pabst, M.
AU - Wu, S. Q.
AU - Grass, J.
AU - Goldring, M. B.
AU - Chiari, C.
AU - Kolb, A.
AU - Altmann, F.
AU - Viernstein, H.
AU - Unger, F. M.
PY - 2010
Y1 - 2010
N2 - 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 α-2,3 or α-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 interleukin-1β (IL-1β) or tumour necrosis factor-α (TNF-α) on primary cells were assessed. Results: Primary human chondrocytes predominantly express α-2,6-specific SiaTs and accordingly, α-2,6-linked sialic acid residues in glycoprotein N-glycans. In contrast, the preponderance of α-2,3-linked sialyl residues and, correspondingly, reduced levels of α-2,6-specific SiaTs are associated with the altered chondrocyte phenotype of C-28/I2 and SW1353 cells. Importantly, a considerable shift towards α-2,3-linked sialic acids and α-2,3-specific SiaT mRNA levels occurred in primary chondrocytes treated with IL-1β or tumour necrosis factor-alpha (TNF-α). Conclusion: The expression of the differentiated chondrocyte phenotype is linked to the ratio of α-2,6- to α-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.
AB - 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 α-2,3 or α-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 interleukin-1β (IL-1β) or tumour necrosis factor-α (TNF-α) on primary cells were assessed. Results: Primary human chondrocytes predominantly express α-2,6-specific SiaTs and accordingly, α-2,6-linked sialic acid residues in glycoprotein N-glycans. In contrast, the preponderance of α-2,3-linked sialyl residues and, correspondingly, reduced levels of α-2,6-specific SiaTs are associated with the altered chondrocyte phenotype of C-28/I2 and SW1353 cells. Importantly, a considerable shift towards α-2,3-linked sialic acids and α-2,3-specific SiaT mRNA levels occurred in primary chondrocytes treated with IL-1β or tumour necrosis factor-alpha (TNF-α). Conclusion: The expression of the differentiated chondrocyte phenotype is linked to the ratio of α-2,6- to α-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.
KW - Cell-matrix interaction
KW - Chondrocytes
KW - Differentiation
KW - Extracellular matrix
KW - Glycoproteins
KW - Phenotype
KW - Sialic acids
KW - Sialyltransferases
UR - http://www.scopus.com/inward/record.url?scp=74149084088&partnerID=8YFLogxK
U2 - 10.1016/j.joca.2009.09.004
DO - 10.1016/j.joca.2009.09.004
M3 - Article
C2 - 19800998
AN - SCOPUS:74149084088
SN - 1063-4584
VL - 18
SP - 240
EP - 248
JO - Osteoarthritis and Cartilage
JF - Osteoarthritis and Cartilage
IS - 2
ER -