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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
Heparan sulfate is a glycosaminoglycan-based polysaccharide which consists of a linear chain containing repeating units of D-glucuronic acid and iduronic acid in combination with either sulfated or acetylated D-glucosamine residue (Li et al. 2016). The biological activity of heparan sulfate may vary depending on the presence of sulfated residue (Wang, Dhurandhare et al. 2021).
Antithrombin–Heparin Complexes
Published in Severian Dumitriu, Valentin Popa, Polymeric Biomaterials, 2020
Leslie R. Berry, Anthony K.C. Chan
Heparin is a member of the GAG family of molecules that occur not only in mammalians but also in most multicellular, as well as in some single cell, organisms [81]. GAGs are straight-chain polysaccharides, which are composed of repeating uronic acid–hexosamine disaccharide units [82]. Heparin and heparan sulfate GAGs contain glucosamine derivative residues, whereas dermatan sulfate and the other chondroitins contain galactosamine [82]. Regarding uronic acid content, heparin and heparan sulfate contain both glucuronic and iduronic residues [82]. Saccharides in GAG chains are extensively modified during and after glycosidic polymerization. In the case of heparin and heparan sulfate, glucosamine residues can be N-acetylated or N-sulfated. However, while >80% of the glucosamines are N-sulfated in heparin, approximately equal amounts of N-sulfated and N-acetylated glucosamines have been detected in various sources of heparan sulfate [83]. Furthermore, whereas there are ≥?2 O-sulfates per disaccharide unit in heparin [84], O-sulfation per disaccharide in heparan sulfate has been found to range from 0.2 to 0.75 [83]. Thus, from these and other structural observations, it has been concluded that heparin and heparan sulfate represent separate groups of N-sulfated GAGs.
Cell Adhesion in Animal Cell Culture: Physiological and Fluid-Mechanical Implications
Published in Martin A. Hjortso, Joseph W. Roos, Cell Adhesion, 2018
Manfred R. Koller, Eleftherios T. Papoutsakis
The major extracellular protein of focal adhesions is vitronectin. Although both fibronectin and vitronectin are capable of forming focal adhesions independently (30), fibronectin is specifically cleared from these sites over time and is replaced by vitronectin (31). The majority of adhesion-promoting activity in serum is accounted for by vitronectin (30), which is present at a concentration of ~ 300 μg/ml in serum. Without these serum proteins, or in the presence of nonspecific proteins such as BSA, cells will not form focal adhesions, although eventually some cells will synthesize and secrete enough fibronectin onto the surrounding substratum to allow their attachment (32). Fibronectin and vitronectin have several properties that allow them to act as attachment proteins. For instance, fibronectin is a very sticky molecule which may bind to fibrin, heparan, collagen, cell receptors, DNA, IgG, plasminogen, and even to another fibronectin molecule (33). The essential features of these molecules in the formation of focal adhesions are the heparan sulfate proteoglycan binding and the cell receptor binding domains (22). Heparan sulfate is a glycosaminoglycan, which is a repeating polymer of -(N-acetylglucosamine-uronic acid)n-disaccharide units. The sugars in the polymer chain are sulfated to varying degrees, and many heparan sulfate chains bind to a core protein to form a heparan sulfate proteoglycan. Proteoglycans are a very diverse group of large macromolecules that fill up much extracellular space and interact with many other molecules through their charged moieties. Proteoglycans also exist on the surface of cells, and it is probably these cell surface proteoglycans that play an augmenting role in the attachment of cells to fibronectin and vitronectin (34). The segment of fibronectin and vitronectin that binds to cell receptors contains the tripeptide sequence Arg-Gly-Asp (RGD), which is responsible for recognition (35). When coated onto a surface, short synthetic polypeptides containing the RGD sequence have been shown to promote cell attachment, whereas in solution they competitively inhibit cell attachment to a surface coated with either fibronectin or the polypeptides themselves (33). The RGD sequence is the cell recognition site of a number of extracellular matrix proteins, including: fibronectin, vitronectin, collagen types I, III, IV, V, and VI, and laminin (36).
Cloning, expression, and characterization of a novel heparinase I from Bacteroides eggerthii
Published in Preparative Biochemistry & Biotechnology, 2020
Cai-Yun Liu, Wen-Bin Su, Li-Bin Guo, Ye-Wang Zhang
As one of the most widely used bacterial polysaccharide lyase, heparinase I (Hep I, EC 4.2.2.7) is capable of degrading heparin and heparan sulfate at specific 1→4 linkages between hexosamines and uronic acids via a β-elimination mechanism.[1] It has some important medical applications including structure analysis of heparin, detection and removal of heparin contaminants[2,3] and the regional heparinization of human blood.[4,5] In addition, heparinase also has been applied in inhibiting the invasion and metastasis of tumor cells.[6–8] In the pharmaceutical industry, Hep I can be used to degrade unfractionated heparin into low molecular weight heparin (LMWH) which is the derivative produced in the enzymatic or chemical degradational process of heparin. LMWH has a similar antithrombotic ability with heparin but lower anticoagulant ability, so it is considered as an ideal anticoagulant drug to the crude heparin in anticoagulant therapy and shows several advantages over ungraded heparin, such as improved pharmacokinetics, better bioavailability and higher safety in clinical applications.[9–11]
Tailored functionalization of poly(L-lactic acid) substrates at the nanoscale to enhance cell response
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Irene Carmagnola, Valeria Chiono, Martina Abrigo, Elia Ranzato, Simona Martinotti, Gianluca Ciardelli
Homogeneous LbL coating generally requires the deposition of at least 5 bilayers [40], as confirmed by our findings. We performed cell tests on samples coated with 19 and 20 layers, because the physico-chemical characterizations suggested the homogeneity of such coatings. LbL self-assembly coating is a versatile technique, allowing the preparation of multilayered films with tailored structure and properties. The in vitro cellular results confirmed that LbL coating promoted fibroblast and myoblast proliferation compared to PLLA films (Figure 8 and Figure 9), when an even (CH, 20 layers) and odd (HE, 19 layers) number of layers was deposited, respectively. In general, the improved cell adhesion may be due to increased surface hydrophilicity. Additionally, the chemical nature of the interface may affect cell adhesion directly (by its composition) or indirectly by the adsorption of proteins present in the culture medium or secreted by cells. It is well known that CH has good biocompatibility toward fibroblasts [63, 64]. On the other hand, HE probably adsorbed proteins (including growth factors) present in the media or secreted by cells favouring C2C12 cells attachment and proliferation. It is well known that heparin and heparan sulfate proteoglycans present on the cell surface and in the extracellular matrix play a key role in the myogenic differentiation [65]. C2C12 myoblasts and fibroblasts showed a similar behaviour, with an increase in cell attachment, cell viability and proliferation as a function of culture time (Figure 8).
Polyclonal antibody production against rGPC3 and their application in diagnosis of hepatocellular carcinoma
Published in Preparative Biochemistry and Biotechnology, 2018
Shenghao Wang, Muhammad Kalim, Keying Liang, Jinbiao Zhan
Glypican-3 (GPC3), a member of the glypican family, is composed of a membrane-associated protein core substituted with various heparan sulfate chains. The core protein of GPC3 is encoded by the GPC3 gene located at q26.2 of human X chromosome. It possesses 40 kDa N-terminal and 30 kDa C-terminal proteins. This protein has a conserved sequence of 14 cysteine residues, so it is easy to form disulfide within the molecule.[1] It also has two heparin sulfate chains at C-terminal near cell membrane.[2] GPC3 is overexpressed in 70% of HCC tissues but does not express in benign liver lesions, cirrhosis, hepatitis, or healthy adult tissues. So, GPC3 has been used as immunohistochemical markers for distinguishing HCC with benign liver lesions[3] because GPC3 can be cleaved from GPI anchoring site from the outer surface of the cell membrane and enter the bloodstream.[4] Clinical and laboratory studies revealed that GPC3-positive HCC patients have a lower survival rate than GPC3-negative HCC patients and showed the high potency of GPC3 in the prognosis of primary liver cancer.