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.

Aryl sulfatase activities in normal and pathologic human articular cartilage.

Abstract: Aryl sulfatase A and B activities were measured in articular cartilage of patients with osteoarthritis, chondromalacia, avascular necrosis, and femoral neck fractures. Although the activities of both enzymes were higher in the tissue from individuals with degenerative joint disease, the most significant finding was the substantial increase in the B:A ratio in these tissues. It is suggested that whereas cerebroside sulfate is the substrate for aryl sulfatase A, either chondroitin sulfate or keratan sulfate is the physiologic substrate for aryl sulfatase B.

Differential expression of the keratan sulphate proteoglycan, keratocan, during chick corneal embryogenesis

Abstract: Keratan sulphate (KS) proteoglycans (PGs) are key molecules in the connective tissue matrix of the cornea of the eye, where they are believed to have functional roles in tissue organisation and transparency. Keratocan, is one of the three KS PGs expressed in cornea, and is the only one that is primarily cornea-specific. Work with the developing chick has shown that mRNA for keratocan is present in early corneal embryogenesis, but there is no evidence of protein synthesis and matrix deposition. Here, we investigate the tissue distribution of keratocan in the developing chick cornea as it becomes compacted and transparent in the later stages of development. Indirect immunofluorescence using a new monoclonal antibody (KER-1) which recognises a protein epitope on the keratocan core protein demonstrated that keratocan was present at all stages investigated (E10–E18), with distinct differences in localisation and organisation observed between early and later stages. Until E13, keratocan appeared both cell-associated and in the stromal extracellular matrix, and was particularly concentrated in superficial tissue regions. By E14 when the cornea begins to become transparent, keratocan was located in elongate arrays, presumably associated along collagen fibrils in the stroma. This fibrillar label was still concentrated in the anterior stroma, and persisted through E15–E18. Presumptive Bowman’s layer was evident as an unlabelled subepithelial zone at all stages. Thus, in embryonic chick cornea, keratocan, in common with sulphated KS chains in the E12–E14 developmental period, exhibits a preferential distribution in the anterior stroma. It undergoes a striking reorganisation of structure and distribution consistent with a role in relation to stromal compaction and corneal transparency.

FGF-2- and TGF-β1-induced downregulation of lumican and keratocan in activated corneal keratocytes by JNK signaling pathway.

Abstract: The cornea is a transparent avascular refractive structure consisting of three tissue layers, epithelium, stroma, and endothelium. A well-organized extracellular matrix (ECM) containing densely packed and regularly spaced thin collagen fibrils of uniform diameter, is largely responsible for transparency in the corneal stroma.1–3 Keratan sulfate proteoglycans (KSPGs) in the stromal ECM play a critical role in the development and maintenance of corneal transparency. Keratocan and lumican, the major KSPGs in the corneal stroma, regulate both fibril diameter and interfibrillar spacing as evident from the phenotype of lumican and keratocan knockout mice.4–9 Keratocan knockout mice have a thinner corneal stroma with irregular collagen fibril organization compared with the normal mice,8 and lumican knockout mice have increased collagen fibril diameter and develop opaque corneas.4,5 Corneal stromal cells (keratocytes), which synthesize keratocan and lumican during development, become quiescent in a fully-developed cornea. However, after an injury to the cornea, growth factors and cytokines originating from corneal epithelial cells, inflammatory cells, and tear fluid activate the keratocytes to fibroblast or myofibroblast phenotypes (reviews, see Refs. 10–14). Keratocan and lumican synthesis is downregulated in the activated keratocytes during wound healing.15–18 KSPG expression is also downregulated in vitro when cultured keratocytes are activated with growth factors including FGF-2 and TGF-β1.19–23 Therefore, an in vitro model of keratocyte activation is useful to study the signaling mechanisms that downregulate the expression of KSPGs. We had previously demonstrated that activation of the small GTPase Rho and its downstream target Rho kinase (ROCK) regulate several undesirable phenotypic changes including the downregulation of KSPGs in the activated keratocytes.23 Jun N-terminal kinase (JNK), a member of the mitogen activated protein kinase (MAPK) family, has been shown to mediate some of the Rho/ROCK regulated events.24–26 The present study was designed to investigate whether JNK activation is responsible for the observed TGF-β1– and FGF-2–induced downregulation of KSPGs in activated keratocytes.

The characterization of angiogenesis inhibitor from shark cartilage.

Abstract: An angiogenesis inhibitor isolated from shark cartilage, SCF2, has been characterized. SCF2 was shown to have specific angiogenesis-inhibiting activity in endothelial cell culture assays. Results of structural and functional studies indicate that the inhibitor is not a typical protein. It is a heat-stable proteoglycan, which contains keratan sulfate units and peptide. Gel filtration chromatography shows that the molecular weight of the angiogenesis inhibitor is about 10 kd.