Acharan Sulfate Research Articles

Nucleolin: acharan sulfate-binding protein on the surface of cancer cells.

Glycosaminoglycans (GAGs) are complex polysaccharides that participate in the regulation of physiological processes through the interactions with a wide variety of proteins. Acharan sulfate (AS), isolated from the giant African snail Achatina fulica, primarily consists of the repeating disaccharide structure alpha-D-N-acetylglucosaminyl (1-->4) 2-sulfoiduronic acid. Exogenous AS was injected subcutaneously near the tumor tissue in C57BL/6 mice that had been implanted with Lewis lung carcinoma cells (LLCs). The location of AS in the tumor was assessed by staining of sectioned tissues with alcian blue and periodic acid-Schiff (PAS) reagent. In vitro assays indicated binding of cells to 50 microg/ml AS (or heparin) after a 5-h incubation. Immunofluorescence assays, using anti-AS antibody, detected AS at the cell surface. The outer-surface of LLCs were next biotinylated to identify the AS-binding proteins. Biotinylated cells were lysed, and the lysates were fractionated on the AS affinity column using a stepwise salt gradient (0, 0.1, 0.3, 0.5, 0.7, 1.0, and 2.0 M). The fractions were analyzed by SDS-PAGE with silver staining and western blotting. We focused on the proteins with high affinity for AS (eluting at 1 M NaCl) and detected only two bands by western blotting. ESI Q-TOF MS analysis of one of these bands, molecular weight approximately 110 kDa, showed it to be nucleolin. A phosphorylated form of nucleolin on the surface of cells acts as a cell surface receptor for a variety of ligands, including growth factors (i.e., basic fibroblast growth factor) and chemokines (i.e., midkine). These results show that nucleolin is one of several AS-binding proteins and suggest that AS might demonstrate its tumor growth inhibitory activity by binding the nucleolin receptor protein on the surface of cancer cells.

Acharan sulfate, the new glycosaminoglycan from Achatina fulica Bowdich 1822. Structural heterogeneity, metabolic labeling and localization in the body, mucus and the organic shell matrix.

Acharan sulfate, a recently discovered glycosaminoglycan isolated from Achatina fulica, has a major disaccharide repeating unit of -->4)-2-acetyl,2-deoxy-alpha-d-glucopyranose(1-->4)-2-sulfo-alpha-l-idopyranosyluronic acid (1-->, making it structurally related to both heparin and heparan sulfate. It has been suggested that this glycosaminoglycan is polydisperse, with an average molecular mass of 29 kDa and known minor disaccharide sequence variants containing unsulfated iduronic acid. Acharan sulfate was found to be located in the body of this species using alcian blue staining and it was suggested to be the main constituent of the mucus. In the present work, we provide further information on the structure and compartmental distribution of acharan sulfate in the snail body. Different populations of acharan sulfate presenting charge and/or molecular mass heterogeneities were isolated from the whole body, as well as from mucus and from the organic shell matrix. A minor glycosaminoglycan fraction susceptible to degradation by nitrous acid was also purified from the snail body, suggesting the presence of N-sulfated glycosaminoglycan molecules. In addition, we demonstrate the in vivo metabolic labeling of acharan sulfate in the snail body after a meal supplemented with [35S]free sulfate. This simple approach might be applied to the study of acharan sulfate biosynthesis. Finally, we developed histochemical assays to localize acharan sulfate in the snail body by metachromatic staining and by histoautoradiography following metabolic radiolabeling with [35S]sulfate. Our results show that acharan sulfate is widely distributed among several organs.

Long duration of anticoagulant activity and protective effects of acharan sulfate in vivo

Introduction: We previously reported that a new glycosaminoglycan, acharan sulfate (AS) from the African giant snail Achatina fulica showed anticoagulant activity in vitro, but was much less active when compared to heparin. In the present study, the anticoagulant activity of AS was investigated in vivo. Methods: AS and heparin were administered to mice and rats in various doses and the anticoagulant activities were measured by aPTT assay. Both were also compared in a thrombin-induced lethality animal model. As one of the possible mechanisms, AS-thrombin interaction was studied by using surface plasmon resonance spectroscopy. Results: Intravenous administration of AS to mice prolonged the clotting time (aPTT) in a time and dose-dependent manner. Although the anticoagulant activity was low in rats, it steadily increased over 5 h after administration of AS (30 mg/kg). In contrast, the increase in aPTT induced by 5 mg/kg of heparin was restored to a normal level after 3 h. In a thrombin-induced lethality model in mice, AS (20 mg/kg) protected against lethality by 80%, while heparin (20 mg/kg) did not show any protective activity beyond 3.5 h post-administration. AS could be also detected in plasma even 5 h after i.v. administration to rats. The binding constant ( K D) of AS to thrombin was 7.27×10 -6 M, corresponding to moderate binding affinity. Conclusions: These results show that the longer duration of AS in blood could prolong the clotting time determined by aPTT and offering protection against thrombin-induced lethality. One possible mechanism may result from AS-thrombin interaction.

Purification and characterization of novel salt-active acharan sulfate lyase from Bacteroides stercoris HJ-15.

Salt-active acharan sulfate lyase (no EC number) has been purified from Bacteroides stercoris HJ-15, which was isolated from human intestinal bacteria with GAG degrading enzymes. The enzyme was purified to apparent homogeneity by a combination of QAE-cellulose, diethylaminoethyl (DEAE)-cellulose, CM-Sephadex C-50, HA ultrogel and phosphocellulose column chromatography with the final specific activity of 81.33 micro mol x min-1 x mg-1. The purified salt-active acharan sulfate lyase was activated to 5.3-fold by salts (KCl and NaCl). The molecular weight of salt-active acharan sulfate lyase was 94 kDa by SDS/PAGE and gel filtration. The salt-active acharan sulfate lyase showed optimal activity at pH 7.2 and 40 degrees C. Salt-active acharan sulfate lyase activity was potently inhibited by Cu2+, Ni2+ and Zn2+. This enzyme was inhibited by some agents, butanediol and p-chloromercuric sulfonic acid, which modify arginine and cysteine residues. The purified Bacteroidal salt-active acharan sulfate lyase acted to the greatest extent on acharan sulfate, to a lesser extent on heparan sulfate and heparin. The biochemical properties of the purified salt-active acharan sulfate lyase are different from those of the previously purified heparin lyases. However, these findings suggest that the purified salt-active acharan sulfate lyase may belong to heparin lyase II.

Suppression of tumor growth by a new glycosaminoglycan isolated from the African giant snail Achatina fulica

Acharan sulfate is a new type of glycosaminoglycan from the giant African snail, Achatina fulica. Acharan sulfate, which has a primary repeating disaccharide structure of α- d- N-acetylglucosaminyl-2- O-sulfo-α- l-iduronic acid, was studied as a potential antitumor agent in both in vivo and in vitro assays. The antiangiogenic activity of acharan sulfate was evaluated in the chorioallantoic membrane assay and by measuring its effect on the proliferation of calf pulmonary artery endothelial cells. In vivo, a matrigel plug assay showed that acharan sulfate suppressed basic fibroblast growth factor (bFGF)-stimulated angiogenesis and lowered the hemoglobin (Hb) content inside the plug. Acharan sulfate was administered s.c. at two doses for 15 days to C57BL/6 mice implanted with murine Lewis lung carcinoma in the back. It was also administered i.p. to ICR mice bearing sarcoma 180 at a dose of 30 mg/kg. Subcutaneous injection of acharan sulfate at doses of 10 and 30 mg/kg decreased tumor weight and tumor volume by 40% without toxicity or resistance. Intraperitoneal injection of acharan sulfate also decreased tumor weight and volume by 40% in sarcoma 180-bearing mice. These results suggest that the antitumor activity of acharan sulfate may be related to the inhibition of angiogenesis.

Pharmacological activities of a new glycosaminoglycan, acharan sulfate isolated from the giant African snail Achatina fulica.

Acharan sulfate (AS) is a glycosaminoglycan (GAG) prepared from the giant African snail, Achatina fulica. In this study, some biological activities of AS were evaluated on the basis of structural similarities to heparin/heparan sulfate and the biological functions of GAGs. We demonstrated that it exhibited strong immunostimulating activities as measured by carbon clearance test in mice and in vivo phagocytosis. It also exhibited a significant hypoglycemic activity in epinephrine (EP)-induced hyperglycemia as well as antifatigue effects by weight-loaded forced swimming test. And it showed hypolipidemic activities in cholesterol-rich mixture induced hyperlipidemia in rats. The above results indicate that AS has diverse biological activities and suggest therapeutically important target molecules.

Localization and characterization of acharan sulfate in the body of the giant African snail Achatina fulica

Acharan sulfate is a glycosaminoglycan (GAG), having the structure →4)-2-acetamido-2-deoxy-α- d-glucopyranose(1→4)-2-sulfo-α- l-idopyranosyluronic acid (1→, isolated from the body of the giant African snail Achatina fulica. This GAG represents 3–5% of the dry weight of this snail's soft body tissues. Frozen sections and polyester wax sections of the snail's body were stained by Alcian blue-periodic acid-Schiff's reagent (PAS) to localize acharan sulfate. Alcian blue staining indicated that GAG was mainly secreted into the outer surface of the body from internal granules. A highly mucous material was collected and treated and the acharan sulfate was recovered by ethanol and cetyl pyridinium chloride precipitation. Crude acharan sulfate was purified by DEAE-Sephacel ion-exchange chromatography. Depolymerization of intact mucus and purified acharan sulfate fractions by heparin lyase II (heparitinase I) from Flavobacterium heparinum produced an unsaturated disaccharide as a major product, establishing the repeating unit of acharan sulfate. These results demonstrate that mucus in the granule and secreted to the outside of the body is composed entirely of acharan sulfate.

Purification and characterization of acharan sulfate lyases, two novel heparinases, from Bacteroides stercoris HJ-15.

Two novel acharan sulfate lyases (ASL1 and ASL2: no EC number) have been purified from Bacteroides stercoris HJ-15 which was isolated from human intestinal bacteria with glycosaminoglycan (GAG) degrading enzymes. These enzymes were purified to apparent homogeneity by a combination of QAE-cellulose, DEAE-cellulose, carboxymethyl-Sephadex C-50, hydroxyapatite and HiTrap SP Sephadex C-25 column chromatography with the final specific activity of 50.5 and 76.7 micromol.min-1.mg-1, respectively. Both acharan sulfate lyases are single subunits of 83 kDa by SDS/PAGE and gel filtration. ASL1 showed optimal activity at pH 7.2 and 45 degrees C. ASL1 activity was inhibited by Cu2+, Ni2+ and Co2+, but ASL2 activity was inhibited by Cu2+, Ni2+and Pb2. Both enzymes were slightly inhibited by some agents that modify histidine and cysteine residues, but activated by reducing agents such as DL-dithiothreitol and 2-mercaptoethanol. Both purified bacteroidal acharan sulfate lyases acted to the greatest extent on acharan sulfate, and to a lesser extents on heparan sulfate and heparin. They did not act on de-O-sulfated acharan sulfate. These findings suggest that the biochemical properties of these purified acharan sulfate lyases are different from those of the previously purified heparin lyases, but these enzymes belong to heparinase II.

Purification and characterization of a novel heparinase from Bacteroides stercoris HJ-15.

A novel type of heparinase (heparin lyase, no EC number) has been purified from Bacteroides stercoris HJ-15, isolated from human intestine, which produces three kinds of heparinases. The enzyme was purified to apparent homogeneity by a combination of QAE-cellulose, DEAE-cellulose, CM-Sephadex C-50, hydroxyapatite, and HiTrap SP chromatographies with a final specific activity of 19.5 mmol/min/mg. It showed optimal activity at pH 7.2 and 45 degrees C and the presence of 300 mM KCl greatly enhanced its activity. The purified enzyme activity was inhibited by Cu(2+), Pb(2+), and some agents that modify histidine and cysteine residues, and activated by reducing agents such as dithiothreitol and 2-mercaptoethanol. This purified Bacteroides heparinase is an eliminase that shows its greatest activity on bovine intestinal heparan sulfate, and to a lesser extent on porcine intestinal heparan sulfate and heparin. This enzyme does not act on acharan sulfate but de-O-sulfated acharan sulfate and N-sulfoacharan sulfate were found to be poor substrates. The substrate specificity of this enzyme is similar to that of Flavobacterial heparinase II. However, an internal amino acid sequence of the purified Bacteroides heparinase shows significant (73%) homology to Flavobacterial heparinase III and only 43% homology to Flavobacterial heparinase II. These findings suggest that the Bacteroidal heparinase is a novel enzyme degrading GAGs.

Effect of Fully Sulfated Glycosaminoglycans on Pulmonary Artery Smooth Muscle Cell Proliferation

Fully sulfated heparin and other glycosaminoglycans, namely heparan, chondroitin, and dermatan sulfates, and hyaluronan have been prepared by using sulfur trioxide under mild chemical conditions. All these derivatives were assayed for antiproliferative activity on cultured bovine pulmonary artery smooth muscle cells (BPASMCs). No appreciable difference was found between heparin and fully sulfated heparin. Chondroitin and dermatan sulfates actually stimulated BPASMCs growth but full sulfonation made them strongly antiproliferative. Native hyaluronan was not antiproliferative but became strongly so after sulfonation. Neither acharan sulfate nor N-sulfoacharan sulfate had any antiproliferative activity. This suggests that O-sulfonation of the polysaccharide is critical for antiproliferative activity, whereas N-sulfonation of glucosamine residues is not.

Heparin, Chemically Modified Heparins, and Acharan Sulfate Differentially Regulate Complement Activity

Heparin, Chemically Modified Heparins, and Acharan Sulfate Differentially Regulate Complement Activity

Chemical Sulfonation and Anticoagulant Activity of Acharan Sulfate

Acharan sulfate is a glycosaminoglycan prepared from the giant African snail, Achatina fulica. This polysaccharide has a repeating disaccharide structure of →4)-2-deoxy-2-acetamido-α-D-glucopyranose (1→4)-2-sulfo-α-L-idopyranosyluronic acid (1→). Its structure is related to heparin and heparan sulfate but is distinctly different from all known members of these classes of glycosaminoglycans. Because of its structural similarities to heparin, chemically modified acharan sulfate was studied to understand the chemical structure effected its anticoagulant activity. After de- N-acetylation, acharan sulfate was N-sulfonated using either chlorosulfonic acid-pyridine or sulfur trioxide-trimethylamine complex. The sulfate level in these products ranged from 22 to 24%(w/w), significantly less than that of heparin at 36%. The molecular weight of both N-sulfoacharan sulfates were comparable with that of heparin. In vitro anticoagulant activity assays showed that N-sulfoacharan sulfate derivatives were moderately active for the inhibition of thrombin and neither product showed any measurable anti–factor Xa activity. The differences in the activities of N-sulfoacharan sulfates produced by these two methods are probably ascribable to a small level of concomitant O-sulfonation obtained when using chlorosulfonic acid-pyridine.

Degradation of acharan sulfate and heparin by Bacteroides stercoris HJ-15, a human intestinal bacterium.

When glycosaminoglycan (GAG)-degrading enzymes were measured in normal human stool suspensions, all 5 tested different stools degraded titrable heparin and acharan sulfate. GAG-degrading bacteria were screened from the isolates of human stools. Among them, HJ-15 had the most potent activities of heparinases (GAGs-degrading enzymes). However, HJ-15 produced the enzyme even if in the media without heparin. Acharan sulfate lyase was induced by acharan sulfate and heparin. Heparinase production was also induced by these GAGs. These enzymes, acharan sulfate lyase and heparinase, were produced in exponential and stationary phase of HJ-15 growth, respectively. Optimal pHs of the acharan sulfate lyase and heparinase activities were 7.2 and 7.5, respectively. The biochemical properties of HJ-15 was similar to those of B. stercoris. However, difference from B. stercoris was utilization of raffinose. This HJ-15 also degraded chondroitin sulfates A and C.

Determination of the structure of oligosaccharides prepared from acharan sulfate.

The fine structure of acharan sulfate, a recently discovered glycosaminoglycan isolated from Achatina fulica , was examined. This glycosaminoglycan has a major disaccharide repeating unit of -->4)-alpha-D-GlcNpAc(1-->4)-alpha-L-IdoAp2S(1--> (where GlcNpAc is N -acetylglucosamine, IdoAp is iduronic acid, and S is sulfate) making it structurally related to both heparin and heparan sulfate. Using heparin lyases prepared from Flavobacterium heparinum and a newly isolated heparinase from Bacteroides stercoris , the controlled enzymatic depolymerization of acharan sulfate was undertaken to prepare a mixture of oligosaccharides. Fractionation of this mixture of oligosaccharides by strong-anion-exchange high performance liquid chromatography afforded oligosaccharides that capillary electrophoresis established were sufficiently pure for structural characterization. Electrospray ionization mass spectrometry identified two series of oligosaccharides, one derived from acharan sulfate's major repeating unit and a second minor group of undersulfated oligosaccharides. Proton nuclear magnetic resonance spectroscopy established the structure of these two classes of oligosaccharides to be DeltaUAp2S(1-->[4)-alpha-D-GlcNpAc(1-->4)-alpha-L-IdoAp2S (1-->]n4)- D-GlcNpAcalpha,beta (where n = 0,1,2,3 and DeltaUAp is 4-deoxy-alpha-L- threo -hex-4-enopyranosyluronic acid) and DeltaUAp(1-->[4)- alpha-D-GlcNpAc(1-->4)-alpha-L-IdoAp2S(1-->]m-D-GlcNpAcal pha,beta (where m = 1,2,3). These results suggest the presence of minor sequence variants in acharan sulfate containing unsulfated iduronic acid having the structure -->4)-alpha-D-GlcNpAc(1-->4)-alpha-L-IdoAp(1-->.

Characterization of aBacteroidesspecies from human intestine that degrades glycosaminoglycans

Polysaccharide lyases that can degrade glycosaminoglycans (GAGs) were identified in an anaerobic strain living in the human intestine. The strain was isolated from the stool of a healthy male and identified as Bacteroides sp. strain HJ-15. A detailed taxonomical study indicated the species is a strain of Bacteroides stercoris. The isolate was cultured and the polysaccharide lyase activity was partially purified. This enzyme preparation could act on GAGs containing either glucosamine or galactosamine suggesting the presence of both heparinases and chondroitinases. Various GAGs were incubated with the partially purified enzyme and the products formed were analyzed by strong anion-exchange high performance liquid chromatography and proton nuclear magnetic resonance spectroscopy. These studies demonstrated the presence of at least two types of polysaccharide lyases: heparin lyase and chondroitin sulfate lyase. The eliminative mechanism of these lyase enzymes was confirmed through the isolation of unsaturated disaccharide products. The heparin lyase acted on both heparin and acharan sulfate, a GAG recently isolated from Achatina fulica. The Bacteroides chondroitin lyase, acted on chondroitin sulfates A, B (dermatan sulfate), and C, resembling chondroitin lyase ABC. The presence of a GAG-degrading organism in human intestine may pose problems for the effective oral administration of GAG drugs.Key words: Bacteroides stercoris, glycosaminoglycan, nuclear magnetic resonance spectroscopy, polysaccharide lyase, heparinase, chondroitinase.

Characterization of a Bacteroides species from human intestine that degrades glycosaminoglycans.

Polysaccharide lyases that can degrade glycosaminoglycans (GAGs) were identified in an anaerobic strain living in the human intestine. The strain was isolated from the stool of a healthy male and identified as Bacteroides sp. strain HJ-15. A detailed taxonomical study indicated the species is a strain of Bacteroides stercoris. The isolate was cultured and the polysaccharide lyase activity was partially purified. This enzyme preparation could act on GAGs containing either glucosamine or galactosamine suggesting the presence of both heparinases and chondroitinases. Various GAGs were incubated with the partially purified enzyme and the products formed were analyzed by strong anion-exchange high performance liquid chromatography and proton nuclear magnetic resonance spectroscopy. These studies demonstrated the presence of at least two types of polysaccharide lyases: heparin lyase and chondroitin sulfate lyase. The eliminative mechanism of these lyase enzymes was confirmed through the isolation of unsaturated disaccharide products. The heparin lyase acted on both heparin and acharan sulfate, a GAG recently isolated from Achatina fulica. The Bacteroides chondroitin lyase, acted on chondroitin sulfates A, B (dermatan sulfate), and C, resembling chondroitin lyase ABC. The presence of a GAG-degrading organism in human intestine may pose problems for the effective oral administration of GAG drugs.

Glycosaminoglycans Can Influence Fibroblast Growth Factor-2 Mitogenicity without Significant Growth Factor Binding

Fibroblast growth factors are important heparin binding, mitogenic proteins. The binding site in heparin and heparan sulfate for fibroblast growth factor-2 (basic fibroblast growth factor) has been described as rich in glucosamine-2-sulfate 1→4 linked to iduronic acid-2-sulfate. The glucosamine residue in the heparin binding site is also 6-sulfated. A new glycosaminoglycan, acharan sulfate, has been chemically modified to prepare a polysaccharide,N-sulfoacharan sulfate, consisting of glucosamine-2-sulfate 1→4 linked to iduronic acid-2-sulfate. Acharan sulfate binds very weakly to fibroblast growth factor-2 whileN-sulfoacharan sulfate binds with nearly the same affinity as heparin. Mitogenicity studies were performed using heparan sulfate-free cells stably transfected with fibroblast growth factor receptor-1. Acharan sulfate inhibits heparin's enhancement of fibroblast growth factor-2 mitogenic activity, without affecting cell viability, whileN-sulfoacharan sulfate shows heparin-like activity but at a greatly reduced level. These results suggest additional mechanisms not requiring high affinity glycosaminoglycan binding to fibroblast growth factor-2 may be important in its mitogenic activity.

Glycosaminoglycans: molecular properties, protein interactions, and role in physiological processes

Article de synthese sur les glycosaminoglycanes chez les mammiferes: proprietes et structure des proteoglycanes et des proteines de liaison des glycosaminoglycanes; roles dans la regulation des processus cellulaires et la regulation de l'expression des genes; interaction avec les facteurs de transcription