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Marine Polysaccharides in Pharmaceutical Applications
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Riyasree Paul, Sourav Kabiraj, Sreejan Manna, Sougata Jana
This glycosaminoglycan-based marine polysaccharide consists of β-(1Ñ4) linked N-acetyl glucosamine unit and galactose residue. Based on the protein binding ability of keratan sulfate, it is classified in three different types, i.e. class I, class II and class III which are found in corneal cartilages, small cartilages and nerve tissue precipitates, respectively (Caterson et al. 2018; Tai et al. 1997).
Morquio syndrome/mucopolysaccharidosis type IV/keratan sulfaturia
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
The syndrome was described by Morquio in 1929 [1] in four affected siblings in Uruguay who were the products of a marriage of first cousins of Swedish origin. In the same year, Brailsford [2] described a similar patient in England. The excretion of keratan sulfate in the urine is the defining biochemical feature of patients with this disease, and keratan sulfate has been documented to accumulate in tissues [3–5]. Defective degradation of keratan sulfate leads to its accumulation in those tissues in which it is normally abundant: cartilage, nucleus pulposus and cornea – tissues that are prominent in the clinical manifestation of the disease. Keratan sulfate consists of alternating galactose and N-acetylglucosamine residues; each may be sulfated. The molecular defect in type A or classic Morquio syndrome is in N-acetylgalactosamine-6-sulfatase encoded by the GALNS gene. It is also a galactose-6-sulfatase responsible for the cleavage of the galactose-6-sulfate moieties of keratan sulfate (Figure 80.1) [6–8]. This enzyme also catalyzes the removal of sulfate moieties from N-acetylgalactosamine-6-sulfate residues that are present in chondroitin-6-sulfate (C6S), and this leads to excretion in excess of chondroitin sulfate in Morquio syndrome. The accumulation of the KS and C6S, in bone and cornea leads to a systemic skeletal chondrodysplasia [9].
Structure and Function of Cartilage
Published in Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi, Articular Cartilage, 2017
Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi
Though chondrocytes have been categorized as all belonging to the same phenotype, differences exist in the genetic, synthetic, and mechanical characteristics of cells with respect to their zone of origin in the tissue (Aydelotte and Kuettner 1988; Darling et al. 2004, 2006; Darling and Athanasiou 2005). For instance, superficial zone chondrocytes express the protein proteoglycan 4 (PRG4), also termed lubricin or superficial zone protein (SZP), while middle zone chondrocytes express cartilage intermediate-layer protein (CILP). Superficial zone chondrocytes were also found to attach to tissue culture plastic slower than those from the deeper zones (Siczkowski and Watt 1990). Deep zone cells display a higher level of vimentin (Durrant et al. 1999), which has been hypothesized to resist compression of the cell (Ghadially 1983; Ralphs et al. 1992). Keratan sulfate synthesis has also been observed to gradually increase through cartilage depth (Zanetti et al. 1985; Aydelotte et al. 1988; Aydelotte and Kuettner 1988; Archer et al. 1990; Siczkowski and Watt 1990). The characteristic gene and protein expressions of chondrocytes are closely associated with the matrix constituents of articular cartilage.
Utilization of glycosaminoglycans by the human gut microbiota: participating bacteria and their enzymatic machineries
Published in Gut Microbes, 2022
Parkash Singh Rawat, Ahkam Saddam Seyed Hameed, Xiangfeng Meng, Weifeng Liu
HA is present only in free-form and not as a part of proteoglycans (PGs) in the gut, while other GAG types are present both as part of PGs, forming the extracellular matrices of almost all mammalian tissues, and free-form.28 Sulfated GAGs are highly distributed in the lamina propria, the basal lamina, and the lumen of the crypts of the colonic mucosa.30 HA is the most abundant GAG in the gut epithelium, with a content range of 0.82–0.95 μg/mg of the dry weight of intestinal tissue, followed by HS (0.37–0.5 μg/mg), DS (0.22–0.36 μg/mg), and CS (0.05 μg/mg).31 Although keratan sulfate (KS) is prominently present in non-gut tissues,32 a non-sulfated form called lactosaminoglycan is reported to be present in gastrointestinal tract mucins.29 Under physiological cellular turnover and various pathological conditions, GAGs from the mucosal surfaces are shed into the intestinal lumen.9,27,33 For example, Syndecans, a combination of heparin sulfate and chondroitin sulfate proteoglycan (CSPG), is significantly over-shed in colitis.34 Iozzo, 19879 have shown that approximately 55% of newly synthesized heparin sulfate proteoglycans (HSPG) are secreted and not internalized by the cells.
Macular Corneal Dystrophy: An Updated Review
Published in Current Eye Research, 2021
Shalini Singh, Sujata Das, Chitra Kannabiran, Saumya Jakati, Sunita Chaurasia
MCD appears to be the result of a metabolic abnormality in keratan sulfate.20 Keratan sulfate is found in the corneal epithelium, Bowman’s membrane, keratocytes, Descemet membrane and endothelium. Carbohydrate sulfotransferase (CHST6) gene on chromosome 16(16q22) gene is explained to be important in producing sulfated keratan sulfate which is important glycosoaminoglycan in the adult cornea. CHST6 gene encodes N-acetylglucosamine 6-0-sulfotransferase, an enzyme which transfers sulfate to the unsulfated keratin chains on lumican.21,22 Lumican preserves the crucial size, ordered structure, impacts corneal hydration and hence the corneal transparency. This explains the stromal haze and the loss of corneal transparency due to mutation in CHST6 gene in MCD.
Silver nanoparticle-induced expression of proteins related to oxidative stress and neurodegeneration in an in vitro human blood-brain barrier model
Published in Nanotoxicology, 2019
Asif Manzoor Khan, Barbara Korzeniowska, Vladimir Gorshkov, Muhammad Tahir, Henrik Schrøder, Lilian Skytte, Kaare Lund Rasmussen, Surabhi Khandige, Jakob Møller-Jensen, Frank Kjeldsen
Another interesting finding of this study was the inhibition of keratan sulfate degradation. Keratan sulfate (KS) is an extracellular polysaccharide classified as a member of the glycosaminoglycans. Keratan sulfate has been reported to induce toxicity during axonal regeneration, and its removal from the brain is seen as a protective mechanism for brain cells. The presence of keratan sulfate may enhance the inflammation process, leading to increase oxidative stress and toxicity (Cui et al. 2013; Silver and Miller 2004).