Keratan sulfate

About: Keratan sulfate is a research topic. Over the lifetime, 1253 publications have been published within this topic receiving 57984 citations. The topic is also known as: keratan sulfate & KS.

Structural changes in the large proteoglycan, aggrecan, in different zones of the ovine growth plate

Abstract: The large cartilage proteoglycan, aggrecan, was found to vary throughout the ovine physis corresponding to the maturational state of the resident chondrocytes. Two populations of proteoglycan monomer were observed in articular, epiphyseal, and in the resting zone of growth plate cartilage. These proteoglycans contained chondroitin sulfate glycosaminoglycan chains sulfated predominantly in the 4 position along with lesser amounts of chondroitin-6-sulfate and keratan sulfate. In the proliferative zone of the growth plate, chondrocytes synthesize one population of proteoglycan monomer which was significantly larger than monomer populations in articular, epiphyseal, or resting zone and this size increase could be attributed to an increase in its constituent chondroitin sulfate side chains. As these chondrocytes progress through their life cycle they continue to modify the structural characteristics of the aggrecan molecule they synthesize. Thus, in the hypertrophic region of the growth plate, the proteoglycan monomer is larger again than in the proliferative region. Variation in sulfation pattern on aggrecan chondroitin sulfate side chains is also observed in the hypertrophic region with an increasing proportion of unsulfated residues present, which may play a role in the initiation of mineralization. In addition, increasing amounts of the carbohydrate sequence recognized by monoclonal antibody 7-D-4 are observed in the hypertrophic zone.

1-C-6 epitope in cartilage proteoglycan G2 domain is masked by keratan sulphate.

Abstract: The presence of the protein epitope recognized by monoclonal antibody 1-C-6 was investigated on the globular G1 and G2 domains of pig cartilage proteoglycan core protein. After reduction of disulphide bonds and removal of keratan sulphate chains with keratanase, both G1 and G2 domains were shown to contain the epitope. However, without keratanase digestion the epitope on the G2 domain was poorly detected. The results suggest that a keratan sulphate chain substituted close to the epitope sequence in the G2 domain prevents antibody access to the epitope and thus masks its detection. This shows the 1-C-6 epitope to be a conserved protein sequence in the G2 domain of proteoglycans from different species, but its detection may be masked by glycosylation.

Expression of lumican and fibromodulin following interleukin-1 beta stimulation of disc cells of the human temporomandibular joint

Abstract: Small leucine-rich repeat proteoglycans (SLRP) are present in the extracellular matrix of the temporomandibular joint (TMJ) disc. Lumican and fibromodulin, classified as class 2 SLRPs, play important roles in TMJ assembly, proliferation and inflammation. Degenerative change in the TMJ disc gives rise to the process of internal derangement (ID). In this study, we immunohistochemically examined the expression of lumican and fibromodulin in nine human TMJ specimens and examined the gene expression of both proteoglycans in cultured human TMJ disc cells under interleukin-1 beta (IL-1 β)-stimulated conditions. An articular disc cell line was established by collagenase treatment of a TMJ disc. The subcultured cells were then incubated for 1, 3, 6, 12, 24 or 48 h under both normal and IL-1 β (1 ng/mL) conditions. The gene expression of lumican and fibromodulin was examined using the reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR. We demonstrated that the expression of lumican significantly differs from that of fibromodulin in the deformed disc and that IL-1 β induces a significant increase in lumican mRNA, but not in fibromodulin mRNA, after 24~48 h culture compared to cells cultured in the absence of IL-1 β (P<0.05). These results indicate that lumican and fibromodulin display different behaviors and that lumican may promote regeneration of the TMJ after degeneration and deformation induced by IL-1 β.