A Unique Dermatan Sulfate-like Glycosaminoglycan from Ascidian:

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Oversulfated chondroitin sulfate (CS), dermatan sulfate (DS), and CS/DS hybrid structures bind growth factors, promote the neurite outgrowth of hippocampal neurons in vitro, and have been implicated in the development of the brain. To investigate the expression of functional oversulfated DS structures in the brain, a novel monoclonal antibody (mAb), 2A12, was generated against DS (An-DS) from ascidian Ascidia nigra, which contains a unique iD disaccharide unit, iduronic acid (2-O-sulfate)␣133GalNAc(6-O-sulfate), as a predominant disaccharide. mAb 2A12 specifically reacted with the immunogen, and recognized iD-enriched decasaccharides as minimal structures. The 2A12 epitope was specifically observed in the hippocampus and cerebellum of the mouse brain on postnatal day 7, and the expression in the cerebellum disappeared in the adult brain, suggesting a spatiotemporally regulated expression of this epitope. Embryonic hippocampal neurons were immunopositive for 2A12, and the addition of the antibody to the culture medium significantly reduced the neurite growth of hippocampal neurons. In addition, two minimum 2A12-reactive decasaccharide sequences with multiple consecutive iD units were isolated from the An-DS chains, which exhibited stronger inhibitory activity against the binding of various growth factors and neurotrophic factors to immobilized embryonic pig brain CS/DS chains (E-CS/DS) than the intact E-CS/DS, suggesting that the 2A12 epitope at the neuronal surface acts as a receptor or co-receptor for these molecules. Thus, we have selected a unique antibody that recognizes iD-enriched oversulfated DS structures, which are implicated in the development of the hippocampus and cerebellum in the central nervous system. The antibody will also be applicable for investigating structural alterations in CS/DS in aging and pathological conditions. Chondroitin sulfate (CS)1 and dermatan sulfate (DS), as well as heparan sulfate (HS), are glycosaminoglycans, which are synthesized as carbohydrate side chains covalently attached to a core protein of proteolgycan (PG) (for reviews, see Ref. 1-3). CS/DS-PGs are present at cell surfaces and in the extracellular matrices of most tissues, and are significant components in the mammalian brain, where they participate in neural development by regulating neuronal adhesion and migration, neurite formation, and axonal guidance (for reviews, see . The backbone of CS and DS consists of repeating disaccharide units of -GlcUA-GalNAc-and -IdoUA-GalNAc-, respectively, and hybrid chains composed of both units in varying proportions also exist (9). These disaccharide units are modified during chain elongation by specific sulfotransferases at C-2 of GlcUA/IdoUA and/or C-4 and/or C-6 of GalNAc in various combinations, thereby producing characteristic sulfation patterns and enormous structural diversity for CS, DS, and CS/DS hybrid chains. Recent studies have shown that the GlcUA/IdoUA ratio and sulfation pattern of the brain CS/DS change during development (10 -12), and subpopulations of the bra...

Section: Isolation and Structural Characterization Of Ascidiansupporting

confidence: 80%

Section: Methodsmentioning

confidence: 99%

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A Functional Dermatan Sulfate Epitope Containing Iduronate(2-O-sulfate)α1–3GalNAc(6-O-sulfate) Disaccharide in the Mouse Brain

Bao

Pavão

Santos

et al. 2005

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“…Recombinant human NK1 was expressed in Pichia pastoris and purified from the culture medium, as previously described (32 Preparation of Ascidian DS-DS species were extracted, as peptidoglycans, from the marine tunicates Ascidia nigra and Styela plicata, and purified as previously described (33,34). Their structures were characterized by disaccharide analyses after digestion with chondroitinase ABC (as described below).…”

Section: Methodsmentioning

confidence: 99%

Interactions of Hepatocyte Growth Factor/Scatter Factor with Various Glycosaminoglycans Reveal an Important Interplay between the Presence of Iduronate and Sulfate Density

Catlow

Deakin

Wei

et al. 2008

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Hepatocyte growth factor/scatter factor (HGF/SF) has a cofactor requirement for heparan sulfate (HS) and dermatan sulfate (DS) in the optimal activation of its signaling receptor MET. However, these two glycosaminoglycans (GAGs) have different sugar backbones and sulfation patterns, with only the presence of iduronate in common. The structural basis for GAG recognition and activation is thus very unclear. We have clarified this by testing a wide array of natural and modified GAGs for both protein binding and activation. Comparisons between Ascidia nigra (2,6-O-sulfated) and mammalian (mainly 4-O-sulfated) DS species, as well as between a panel of specifically desulfated heparins, revealed that no specific sulfate isomer, in either GAG, is vital for interaction and activity. Moreover, different GAGs of similar sulfate density had comparable properties, although affinity and potency notably increase with increasing sulfate density. The weaker interaction with CS-E, compared with DS, shows that GlcA-containing polymers can bind, if highly sulfated, but emphasizes the importance of the flexible IdoA ring. Our data indicate that the preferred binding sites in DS in vivo will be comprised of disulfated, IdoA(2S)-containing motifs. In HS, clustering of N-/2-O-/6-O-sulfation in S-domains will lead to strong reactivity, although binding can also be mediated by the transition zones where sulfates are mainly at the N-and 6-O-positions. GAG recognition of HGF/SF thus appears to be primarily driven by electrostatic interactions and exhibits an interesting interplay between requirements for iduronate and sulfate density that may reflect in part a preference for particular sugar chain conformations.

“…Vertebrate tissues express abundant sulfated glycosaminoglycans (2). Invertebrate species are also a rich source of sulfated polysaccharides with novel structures (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”

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confidence: 99%

Structure and Anticoagulant Activity of Sulfated Galactans

Farias

Valente

Pereira

et al. 2000

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263

We have characterized the structure of a sulfated Dgalactan from the red algae Botryocladia occidentalis. Possibly, the addition of two sulfate esters to a single ␣-galactose residue has an "amplifying effect" on the anticoagulant action, which cannot be totally ascribed to the increased charge density of the polymer. These results indicate that the wide diversity of polysaccharides from marine alga and invertebrates is a useful tool to elucidate structure/anticoagulant activity relationships.