Branch distribution pattern and anticoagulant activity of a fucosylated chondroitin sulfate from Phyllophorella kohkutiensis

Fucosylated chondroitin sulfate (FCS) extracted from Phyllophorella kohkutiensis (PkFCS) is composed of d-GalNAc, d-GlcA, l-Fuc and -SO42-. According to the defined structures revealed by NMR spectra of the branches released by mild acid hydrolysis and oligosaccharides generated by β-eliminative depolymerization, the backbone of PkFCS is CS-E, and the branch types attached to C-3 of d-GlcA include l-Fuc2S4S, l-Fuc3S4S, l-Fuc4S, and the disaccharide α-d-GalNAc-1,2-α-l-Fuc3S4S with the ratio of 43:13:22:22. Notably, novel heptasaccharide and hendecasaccharide were identified that are branched with continuous distribution of the disaccharide. The structural sequences of the oligosaccharides indicate that three unique structural motifs are present in the entire PkFCS polymer, including a motif branched with randomly distributed different sulfated l-Fuc units, a motif containing regular l-Fuc2S4S branches and a motif enriched in α-d-GalNAc-1,2-α-l-Fuc3S4S. This is the first report about the distribution pattern of diverse branches in natural FCS. Natural PkFCS exhibited potent anticoagulant activity on APTT prolonging and anti-iXase activity. Regarding the structurally defined oligosaccharides with sulfated fucosyl side chains, octasaccharide (Pk4b) is the minimum fragment responsible for its anticoagulant activity correlated with anti-iXase. However, further glycosyl modification with a non-sulfated d-GalNAc at the C-2 position of l-Fuc3S4S could significantly decrease the anticoagulant and anti-iXase activity.

Chondroitin Sulfate from Oreochromis niloticus Waste Reduces Leukocyte Influx in an Acute Peritonitis Model

Oreochromis niloticus (tilapia) is one of the most cultivated fish species worldwide. Tilapia farming generates organic waste from fish removal processes in nurseries. Visceral waste can damage natural ecosystems. Therefore, the use of this material as a source of biomolecules helps reduce environmental impacts and improve pharmacological studies. Tilapia viscera were subjected to proteolysis and complexation with an ion-exchange resin. The obtained glycosaminoglycans were purified using ion exchange chromatography (DEAE-Sephacel). The electrophoretic profile and analysis of 1H/13C nuclear magnetic resonance (NMR) spectra allowed for the characterization of the compound as chondroitin sulfate and its sulfation position. This chondroitin was named CST. We tested the ability of CST to reduce leukocyte influx in acute peritonitis models induced by sodium thioglycolate and found a significant reduction in leukocyte migration to the peritoneal cavity, similar to the polymorphonuclear population of the three tested doses of CST. This study shows, for the first time, the potential of CST obtained from O. niloticus waste as an anti-inflammatory drug, thereby contributing to the expansion of the study of molecules with pharmacological functions.

State-of-the-art glycosaminoglycan characterization

Glycosaminoglycans (GAGs) are heterogeneous acidic polysaccharides involved in a range of biological functions. They have a significant influence on the regulation of cellular processes and the development of various diseases and infections. To fully understand the functional roles that GAGs play in mammalian systems, including disease processes, it is essential to understand their structural features. Despite having a linear structure and a repetitive disaccharide backbone, their structural analysis is challenging and requires elaborate preparative and analytical techniques. In particular, the extent to which GAGs are sulfated, as well as variation in sulfate position across the entire oligosaccharide or on individual monosaccharides, represents a major obstacle. Here, we summarize the current state-of-the-art methodologies used for GAG sample preparation and analysis, discussing in detail liquid chromatograpy and mass spectrometry-based approaches, including advanced ion activation methods, ion mobility separations and infrared action spectroscopy of mass-selected species.

Re-understanding of structure and anticoagulation: Fucosylated chondroitin sulfate from sea cucumber Ludwigothurea grisea

Fucosylated chondroitin sulfate (FCS) from sea cucumber Ludwigothurea grisea (FCS_Lg) is the first one that reported to bear the di-fucosyl branches. Here we deciphered it by analyzing the physicochemical properties and its derivatives. Oligosaccharides prepared by selective cleavage of glycosidic linkages presented the mono-fucose and heterodisaccharide branches in FCS_Lg. The disaccharide branch was determined as d-GalNAc_R1-(α1,2)-l-Fuc_R2 rather than the di-fucosyl branch, where R1 was 4-mono-O- or 4,6-di-O-sulfation, and R2 was 3-mono-O- or 3,4-di-O-sulfation, respectively. The diversity of sulfation patterns in branches complicated the structure. These results give us a new understanding of FCS_Lg and provided a reliable method to decipher the FCS with complex branches. Bioanalysis of chemically modified derivatives showed that modulating the molecular mass could enhance the Xase target selectivity. Side chains conferred the Xase complex inhibition by binding to FIXa with a high affinity. Whether monosaccharide and disaccharide branches have differential effects needs to be further explored.

Fucose-Rich Sulfated Polysaccharides from Two Vietnamese Sea Cucumbers Bohadschia argus and Holothuria (Theelothuria) spinifera: Structures and Anticoagulant Activity

Fucosylated chondroitin sulfates (FCSs) FCS-BA and FCS-HS, as well as fucan sulfates (FSs) FS-BA-AT and FS-HS-AT were isolated from the sea cucumbers Bohadschia argus and Holothuria (Theelothuria) spinifera, respectively. Purification of the polysaccharides was carried out by anion-exchange chromatography on DEAE-Sephacel column. Structural characterization of polysaccharides was performed in terms of monosaccharide and sulfate content, as well as using a series of non-destructive NMR spectroscopic methods. Both FCSs were shown to contain a chondroitin core [→3)-β-d-GalNAc-(1→4)-β-d-GlcA-(1→]_n bearing sulfated fucosyl branches at O-3 of every GlcA residue in the chain. These fucosyl residues were different in pattern of sulfation: FCS-BA contained Fuc2S4S, Fuc3S4S and Fuc4S at a ratio of 1:8:2, while FCS-HS contained these residues at a ratio of 2:2:1. Polysaccharides differed also in content of GalNAc4S6S and GalNAc4S units, the ratios being 14:1 for FCS-BA and 4:1 for FCS-HS. Both FCSs demonstrated significant anticoagulant activity in clotting time assay and potentiated inhibition of thrombin, but not of factor Xa. FS-BA-AT was shown to be a regular linear polymer of 4-linked α-L-fucopyranose 3-sulfate, the structure being confirmed by NMR spectra of desulfated polysaccharide. In spite of considerable sulfate content, FS-BA-AT was practically devoid of anticoagulant activity. FS-HS-AT cannot be purified completely from contamination of some FCS. Its structure was tentatively represented as a mixture of chains identical with FS-BA-AT and other chains built up of randomly sulfated alternating 4- and 3-linked α-L-fucopyranose residues.

Capillary Zone Electrophoresis-Electrospray Ionization Tandem Mass Spectrometry for Total Analysis of Chondroitin/Dermatan Sulfate Oligosaccharides

Proteoglycans are heavily glycosylated proteins, covalently linked to one or more glycosaminoglycan (GAG) chains, abundantly expressed in the extracellular matrix (ECM). Among GAGs, chondroitin sulfate (CS) and dermatan sulfate (DS) play an essential role at the ECM level; however, the composition of the hybrid CS/DS as well as the distribution of the sulfate groups along the chain were also shown to influence biological activities in brain. The elevated structural diversity of CS/DS motifs, in which sulfation may occur at GalNAc and/or IdoA/GlcA in various combinations, requires the development of specific high performance analytical methods for reliable elucidation. Due to its sensitivity, reproducibility, and efficiency, capillary zone electrophoresis (CZE) for separation of CS/DS oligosaccharides coupled to electrospray ionization mass spectrometry (ESI-MS) for their structure determination contributed an essential progress to this field.In the present chapter, two powerful methods based on CZE for separation and ESI-MS for identification and structural analysis of CS/DS are presented. The first part is devoted to offline CZE-ESI-MS based on fraction collection, screening by negative ion mode nanoESI, and fragmentation analysis in tandem MS using collision-induced dissociation (CID) at low ion acceleration energies. In the second part of the chapter, a strategy for online CZE-ESI-MS in normal polarity and negative mode ESI followed by tandem MS in real-time data-dependent acquisition mode for CS/DS separation, screening, and fragmentation is described in detail. The latter method entails the in-laboratory manufacturing of a simple yet sturdy interface for the online CZE coupling to ESI-MS and the optimization of the coupled system for total analysis of regularly sulfated and irregularly, i.e., under- and oversulfated CS/DS domains.

The glycosidic bond cleavage and desulfation investigation of fucosylated glycosaminoglycan during mild acid hydrolysis through structural analysis of the resulting oligosaccharides

Mild acid hydrolysis is a common method to study the chemical structure of fucosylated glycosaminoglycan (FG). It was generally considered that the fucose branches α-L-FucS-(1, of FG could be hydrolyzed selectively in mild acid. This report focused on the selectivity of glycosidic bond cleavage and extensive desulfation characteristics of the backbone during mild acid hydrolysis. The hydrolyzed product of native SvFG (dfSvFG) was prepared by mild acid hydrolysis in 0.1 M H₂SO₄ at 100 °C for 2 h. A series of oligosaccharides were purified by GPC and SAX-HPLC from dfSvFG, then they were analyzed by HPGPC, 1D/2D NMR and ESI-Q-TOF-MS. The precise structure of these oligosaccharides was elucidated to be trisaccharides, tetrasaccharides and pentasaccharides, indicating SvFG branches hydrolyzed basically and its' backbone composed of repeating β-D-GlcA-(1,3)-D-GalNAc and β-D-GalNAc-(1,4)-D-GlcA unit. The prevalent presence of the GlcA residues at the non-reducing terminal of these oligosaccharides, suggesting the glycosidic bond of β-D-GalNAc-(1,4)-D-GlcA was more susceptible to acid than that of β-D-GlcA-(1,3)-D-GalNAc during mild acid hydrolysis. Moreover, the sulfate ester groups in GalNAc_4S6S unit could also be hydrolyzed by acid, and it at position C-4 was more susceptible to hydrolysis than that at C-6. This extensive degradation and desulfation of the backbone should be taken into consideration when mild acid hydrolysis was used in elucidating the exact structure or structure-activity relationship of native FG.

Analysis of the Glycosaminoglycan Chains of Proteoglycans

Glycosaminoglycans (GAGs) are heterogeneous, negatively charged, macromolecules that are found in animal tissues. Based on the form of component sugar, GAGs have been categorized into four different families: heparin/heparan sulfate, chondroitin/dermatan sulfate, keratan sulfate, and hyaluronan. GAGs engage in biological pathway regulation through their interaction with protein ligands. Detailed structural information on GAG chains is required to further understanding of GAG-ligand interactions. However, polysaccharide sequencing has lagged behind protein and DNA sequencing due to the non-template-driven biosynthesis of glycans. In this review, we summarize recent progress in the analysis of GAG chains, specifically focusing on techniques related to mass spectroscopy (MS), including separation techniques coupled to MS, tandem MS, and bioinformatics software for MS spectrum interpretation. Progress in the use of other structural analysis tools, such as nuclear magnetic resonance (NMR) and hyphenated techniques, is included to provide a comprehensive perspective.

(Semi)-Synthetic Fucosylated Chondroitin Sulfate Oligo- and Polysaccharides

Fucosylated chondroitin sulfate (fCS) is a glycosaminoglycan (GAG) polysaccharide with a unique structure, displaying a backbone composed of alternating N-acetyl-d-galactosamine (GalNAc) and d-glucuronic acid (GlcA) units on which l-fucose (Fuc) branches are installed. fCS shows several potential biomedical applications, with the anticoagulant activity standing as the most promising and widely investigated one. Natural fCS polysaccharides extracted from marine organisms (Echinoidea, Holothuroidea) present some advantages over a largely employed antithrombotic drug such as heparin, but some adverse effects as well as a frequently found structural heterogeneity hamper its development as a new drug. To circumvent these drawbacks, several efforts have been made in the last decade to obtain synthetic and semi-synthetic fCS oligosaccharides and low molecular weight polysaccharides. In this Review we have for the first time collected these reports together, dividing them in two topics: (i) total syntheses of fCS oligosaccharides and (ii) semi-synthetic approaches to fCS oligosaccharides and low molecular weight polysaccharides as well as glycoclusters displaying multiple copies of fCS species.

Characterization of the Hydrolysis Kinetics of Fucosylated Glycosaminoglycan in Mild Acid and Structures of the Resulting Oligosaccharides

: Mild acid hydrolysis is a common method for the structure analysis of fucosylated glycosaminoglycan (FG). In this work, the effects of acid hydrolysis on the structure of FG from S. variegatus (SvFG) and the reaction characteristic were systemically studied. The degree of defucosylation (DF) and molecular weights (Mw) of partial fucosylated glycosaminoglycans (pFs) were monitored by 1H NMR and size-exclusion chromatography, respectively. The kinetic plots of DF, degree of desulfation (DS) from fucose branches, and degree of hydrolysis (DH) of the backbone are exponentially increased with time, indicating that acid hydrolysis of SvFG followed a first-order kinetics. The kinetic rate constants kDF, kDS, and kDH were determined to be 0.0223 h-1, 0.0041 h-1, and 0.0005 h-1, respectively. The structure of the released sulfated fucose branches (FucS) from SvFG and HfFG (FG from H. fuscopunctata) was characterized by 1D/2D NMR spectroscopy, suggesting the presence of six types of fucose: α/β Fuc2S4S, Fuc3S4S, Fuc3S, Fuc4S, Fuc2S, and Fuc. The Fuc3S4S was more susceptible to acid than Fuc2S4S, and that the sulfate ester in position of O-2 and O-3 than in O-4 of fucose. The structure characteristic of pF18 indicated the cleavage of backbone glycosidic bonds. The APTT prolonged activity reduced with the decrease of the DF and Mw of the pFs, and became insignificant when its DF was 87% with Mw of 3.5 kDa.

Glycosylation at an evolutionary nexus: the brittle star Ophiactis savignyi expresses both vertebrate and invertebrate N-glycomic features

Echinoderms are among the most primitive deuterostomes and have been used as model organisms to understand chordate biology because of their close evolutionary relationship to this phylogenetic group. However, there are almost no data available regarding the N-glycomic capacity of echinoderms, which are otherwise known to produce a diverse set of species-specific glycoconjugates, including ones heavily modified by fucose, sulfate, and sialic acid residues. To increase the knowledge of diversity of carbohydrate structures within this phylum, here we conducted an in-depth analysis of N-glycans from a brittle star (Ophiactis savignyi) as an example member of the class Ophiuroidea. To this end, we performed a multi-step N-glycan analysis by HPLC and various exoglyosidase and chemical treatments in combination with MALDI-TOF MS and MS/MS. Using this approach, we found a wealth of hybrid and complex oligosaccharide structures reminiscent of those in higher vertebrates as well as some classical invertebrate glycan structures. 70% of these N-glycans were anionic, carrying either sialic acid, sulfate, or phosphate residues. In terms of glycophylogeny, our data position the brittle star between invertebrates and vertebrates and confirm the high diversity of N-glycosylation in lower organisms.

NMR characterization and anticoagulant activity of the oligosaccharides from the fucosylated glycosaminoglycan isolated from Holothuria coluber

A glycosaminoglycan was isolated from the sea cucumber Holothuria coluber (HcFG). A series of oligosaccharide fragments (dp range 3-11) were prepared from its β-eliminative depolymerized product (dHcFG). Extensive NMR characterization of the oligosaccharides indicated the d-GlcA-β1,3-d-GalNAc_4S6S repeating disaccharide backbone was substituted by monosaccharide branches comprising of Fuc_2S4S, Fuc_3S4S and Fuc_4S, linked to O-3 of d-GlcA. For the prevailing Fuc_3S4S at nonreducing end of dHcFG, the β-eliminative depolymerization process of HcFG was compared with those of the FGs from Actinopyga miliaris (AmFG, branched with Fuc_3S4S) and Stichopus variegatus (SvFG, branched with Fuc_2S4S). The result suggested that d-GlcA substituted with Fuc_3S4S was more susceptible to depolymerization than that with Fuc_2S4S. It might be due to the larger steric hindrance effects from Fuc_2S4S on the esterification of GlcA. Biological assays confirmed that the minimum chain length (dp8), regardless of the Fuc branch types, was required for the potent anti-iXase and anticoagulant activities in FG fragments.

Bottom-up analysis using liquid chromatography-Fourier transform mass spectrometry to characterize fucosylated chondroitin sulfates from sea cucumbers

Fucosylated chondroitin sulfates (FCSs) from sea cucumbers have repetitive structures that exhibit minor structural differences based on the organism from which they are recovered. A detailed characterization of FCSs and their derivatives is important to establish their structure-activity relationship in the development of new anticoagulant drugs. In the current study, online hydrophilic interaction chromatography-Fourier transform mass spectrometry (FTMS) was applied to analyze the FCS oligosaccharides generated by selective degradation from four species of sea cucumbers, Isostichopus badionotus, Pearsonothuria graeffei, Holothuria mexicana and Acaudina molpadioides. These depolymerized FCS fragments were quantified and compared using the glycomics software package, GlycReSoft. The quantified fragments mainly had trisaccharide-repeating compositions and showed significant differences in fucosylation (including its sulfation) among different species of sea cucumbers. Detailed analysis of FTMS ion peaks and top-down nuclear magnetic resonance spectroscopy of native FCS polysaccharides verified the accuracy of this method. Thus, a new structural model for FCS chains from these different sea cucumbers was defined. This bottom-up approach provides rich detailed structural analysis and provides quantitative information with high accuracy and reproducibility and should be suitable for the quality control in FCSs as well as their oligosaccharides.

Oligosaccharides from depolymerized fucosylated glycosaminoglycan: Structures and minimum size for intrinsic factor Xase complex inhibition

Fucosylated glycosaminoglycan (FG), a structurally complex glycosaminoglycan found up to now exclusively in sea cucumbers, has distinct anticoagulant properties, notably a strong inhibitory activity of intrinsic factor Xase complex (FXase). Knowledge of the FG structures could facilitate the development of a clinically effective intrinsic FXase inhibitor for anticoagulant drugs. Here, a new fucosylated glycosaminoglycan was obtained from the widely traded sea cucumber Bohadschia argus The precise structure was deduced as {→4)-[l-Fuc3S4S-α-(1→3)-]-d-GlcA-β-(1→3)-d-GalNAc4S6S-β-(1} through analysis of its chemical properties and homogeneous oligosaccharides purified from its β-eliminative depolymerized products. The B. argus FG with mostly 3,4-di-O-sulfated fucoses expands our knowledge on FG structural types. This β-elimination process, producing oligosaccharides with well-defined structures, is a powerful tool for analyzing the structure of complex FGs. Among these oligosaccharides, an octasaccharide displayed potent FXase inhibitory activity. Compared with oligosaccharides with various degrees of polymerization (3n and 3n - 1), our analyses reveal that the purified octasaccharide is the minimum structural unit responsible for the potent selective FXase inhibition, because the d-talitol in the nonsaccharide is unnecessary. The octasaccharide with 2,4-di-O-sulfated fucoses is more potent than that of one with 3,4-di-O-sulfated fucoses. Thus, sulfation patterns can play an important role in the inhibition of intrinsic factor Xase complex.

Separation, purification, structures and anticoagulant activities of fucosylated chondroitin sulfates from Holothuria scabra

In this study, a new fucosylated chondroitin sulfate (HsG) with an average molecular weight of 69.1 kDa was isolated from sea cucumber Holothuria scabra. We investigated the structure of the HsG by adopting monosaccharide composition analysis, disaccharide composition analysis, IR,¹H and¹³C NMR spectra and methylation analysis. According to methylation results of desulfated/carboxyl-reduced polysaccharides and the analysis of unsaturated disaccharides generated through the enzymolysis of the defucosed polysaccharides, it is shown that each branch is formed by one fucopyranosyl residue, wherein 55.7% of the fucopyranosyl residues are linked to the O-6 position of the N-acetylgalactosamine moiety, 21.2% of the fucopyranosyl residues are linked to the O-3 position of β-d-glucuronic acid, 13.0% of the fucopyranosyl residues are linked to the O-4 positions of the N-acetylgalactosamine moiety, and 10.1% of the fucopyranosyl residues are not linked to sulfate groups on the backbone. The backbone →4)GlcUAβ(1 → 3)GalNAcβ(1→ and sulfated fucose branches were composed of the β-d-glucuronic acid, N-acetyl-β-d- galactosamine, α-l-fucose and sulfate groups by the molar ratio of 1:1.72:2.34:3.29. The anticoagulant activities of the HsG was evaluated and compared with heparin. The result showed that the HsG could prolong the activated partial thromboplastin time.