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PubMed1997

Involvement of Ras in the expression of glycolipid sulfotransferase in human renal cancer cells.

Glycolipid sulfotransferase activity in a human renal cell carcinoma cell line, SMKT-R3, is enhanced by epidermal growth factor (EGF); tyrosine kinase inhibitors suppress this enhancement. To investigate the involvement of Ras in the signal transduction pathway from the EGF receptor to the expression of glycolipid sulfotransferase, we introduced v-H-ras into SMKT-R3 cells. In a quiescent state, the percent GTP bound to Ras in v-H-ras-expressing cells increased about 2.5-fold compared with control cells, suggesting that v-Ras introduced into the renal cancer cells is in an active form without EGF stimulation. Glycolipid sulfotransferase activity in v-H-ras-expressing cells was higher than in control cells. The sulfotransferase activity was affected neither by EGF nor by genistein, a tyrosine kinase inhibitor, in v-H-ras-expressing cells, whereas it was enhanced by EGF and reduced by genistein in control cells. Our observations suggest that Ras mediates the regulation pathway of glycolipid sulfotransferase activity in SMKT-R3 cells.

Carcinoma, Renal Cell↗

PubMed1993

Induction of the fundic mucosa-specific glycolipid with dimethylformamide in gastric-cancer cell lines.

We have previously reported that a glycolipid GalNAc beta 1-4[NeuAc alpha 2-3]Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc-Cer named NGM-1 is present specifically in the human gastric fundic mucosa, but not in other organs. In gastric-cancer tissue and cancer cell lines, this glycolipid completely disappears. These findings imply that NGM-1 is expressed only in well-differentiated fundic mucosa. The purpose of this study is to examine the expression of NGM-1 as a differentiation-related molecule. A gastric cell line AZ521 was cultured in the medium with various reagents which had been reported to induce differentiation in cancer cells. The growth of AZ521 was suppressed by the addition of 0.8% dimethylformamide (DMF) to the medium, but not by addition of dimethylsulfoxide (DMSO), retinoic acid or butyric acid. In the ganglioside fraction of the cells cultured with DMF, a glycolipid regarded as NGM-1 which had not been present before treatment was detected using a monoclonal antibody. Suppression of the proliferation of AZ521 by eliminating the serum from the medium could not induce the expression of NGM-1. A colonic cell line treated with DMF also failed to express the glycolipid. The synthase activity of NGM-1 was elevated in the AZ521 cells treated with DMF, but not with DMSO. These results demonstrate that the expression of NGM-1 is induced by DMF specifically in gastric-cancer cells, and suggest the possibility that NGM-1 is a differentiation-related molecule.

Butyrates↗

PubMed1995

The phosphatidylinositol-glycolipid anchor on alkaline phosphatase facilitates mineralization initiation in vitro.

Alkaline phosphatase (AP) is required for the proper mineralization of cartilage and bone. The enzyme is localized to the outer surface of cells through a phosphatidylinositol-glycolipid anchor, which is covalently attached to the carboxyl terminus of the protein. In calcifying cartilage, AP-rich matrix vesicles (MVs) are released into the matrix from chondrocytes, and apatite formation is initiated within and around these particles. In this paper we examine the role of the AP glycolipid anchor using an in vitro mineralization assay system. AP was purified to homogeneity, and the purified enzyme was used to drive mineral formation in vitro with and without the anchor. Mineral formation was initiated through phosphate release from beta-glycerol phosphate (beta-GP). The amount of PO4(-3) released was similar whether the anchor was present or absent. However, SEM and X-ray microanalysis revealed that the mineral produced by anchored AP was indistinguishable from that produced by MVs and that both of those minerals were more apatite-like than mineral formed by soluble AP or through spontaneous precipitation. Taken together, the data suggest that in addition to providing PO4(-3) to drive mineralization, AP influences the nature of the mineral formed. Further, AP containing its glycolipid anchor produces mineral comparable with that formed by tissue-derived MVs. Thus, in the absence of extracellular matrix, MV mineralization in vitro can be emulated by glycolipid-anchor containing AP.

Alkaline Phosphatase↗

PubMed1989

Effects of D-threo-PDMP, an inhibitor of glucosylceramide synthetase, on expression of cell surface glycolipid antigen and binding to adhesive proteins by B16 melanoma cells.

Incubating B16 melanoma cells with an inhibitor of glucosylceramide (GlcCer) synthetase, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-threo-PDMP), led to a considerable decrease in the levels of GlcCer and lactosylceramide (LacCer). The content of ganglioside GM3 was little affected, but the ability to bind a monoclonal antibody against the ganglioside (M2590) was greatly reduced, suggesting that the reduction in the simple glycolipids led to encryption of the membrane antigen. This interpretation is supported by the observation that permeabilization of the treated cells with Triton X-100 restored immunological reactivity. Specificity of the PDMP effect was shown by its lack of effect on the reactivity of two other surface antigens to anti-melanoma monoclonal antibodies M562 and M622, and of the major histocompatibility antigens to anti-H-2KbDb monoclonal antibody. The ability of the treated cells to attach to laminin or type IV collagen was lost but that to fibronectin was not. The effects of the enzyme inhibitor were counteracted by including GlcCer in the culture medium. This indicates that the lipid was absorbed by the cells and utilized like endogenously-formed GlcCer. Cells preattached to laminin or collagen could be induced to round up by addition of inhibitor. In contrast, L-threo-PDMP (which does not block the synthesis of GlcCer) had no effect on the immunologic reactivity of GM3 or the adhesion properties of the cells. However, it did produce considerable accumulation of LacCer. These data suggest that the simple glycolipid, GlcCer, is an essential factor for antigenic expression of the more complex glycolipids on cell surfaces and that there is a close association and interaction between glycolipids and adhesive receptors on the cell surface.

Animals↗

PubMed1995

Expression of the glycolipid globotriaosylceramide (Gb3) in testicular carcinoma in situ.

Changes in the cell membrane glycolipid composition and metabolism are frequently associated with carcinogenesis. The accumulation of globo-series glycolipids is the most notable change of the germ cell glycolipid composition observed in testicular tumours. In this study, the expression of the globo-series core-structure, globotriaosylceramide (Gb3) was investigated in the preinvasive stage of testicular germ cell tumours, carcinoma in situ (CIS). Seventeen tissue specimens with CIS and 12 samples of overt testicular tumours were immunostained with anti-Gb3 monoclonal antibody 38-13. The accumulation of Gb3 was detected in 12 CIS samples (70.6%) and in 8 invasive tumour samples (66.7%), including seminoma, non-seminoma and a combined germ cell tumour. Our findings indicate that the composition of glycolipids shift at the common preinvasive stage of testicular germ cell tumours and confirm that Gb3 is a tumour-associated antigen of testicular germ cell neoplasia.

Carcinoma in Situ↗

PubMed1986

Factors affecting surface expression of glycolipids: influence of lipid environment and ceramide composition on antibody recognition of cerebroside sulfate in liposomes.

The reactivity of the acidic glycolipid cerebroside sulfate (CBS) with antibody was studied as a function of its lipid environment in vesicles and of its ceramide composition. The lipid environment was varied by using phosphatidylcholine of varying chain length with cholesterol in a phosphatidylcholine:cholesterol:cerebroside sulfate molar ratio to glycolipid of 1:0.75:0.1. The ceramide structure of CBS was varied by using synthetic forms containing palmitic acid, lignoceric acid, or the corresponding alpha-hydroxy fatty acids. Reactivity with antibody was determined by measuring complement-mediated lysis of the vesicles containing a spin-label marker, tempocholine chloride. The data were analyzed by a theoretical model which gives relative values for the dissociation constant and concentration of antibodies within the antiserum which are able to bind to the glycolipid. If the phosphatidylcholine chain length was increased, increasing the bilayer thickness, only a small population of high-affinity antibodies were able to bind to cerebroside sulfate, suggesting decreased surface exposure of the glycosyl head group. A larger population of lower affinity antibodies were able to bind to it in a shorter chain length phosphatidylcholine environment. However, if the chain length of the cerebroside sulfate was increased, it could be recognized by more antibodies of lower affinity than the short chain length form, suggesting that an increase in chain length of the glycolipid increased surface exposure. Hydroxylation of the fatty acid inhibited antibody binding; only a smaller population of higher affinity antibodies was able to bind to the hydroxy fatty acid forms.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2003

Glycolipid intermembrane transfer is accelerated by HET-C2, a filamentous fungus gene product involved in the cell-cell incompatibility response.

Among filamentous fungi capable of mycelial growth, het genes play crucial roles by regulating heterokaryon formation between different individuals. When fusion occurs between fungal mycelia that differ genetically at their het loci, the resulting heterokaryotic cells are quickly destroyed. It is unclear how het gene products of Podospora anserina trigger heterokaryon incompatibility. One unexplored possibility is that glycosphingolipids play a role because the het-c2 gene encodes a protein that displays 32% sequence identity and an additional 30% similarity to the mammalian glycolipid transfer protein. Here, P. anserina protoplasts containing wild-type het-c2 genes were shown to have greater glycosphingolipid transfer activity than protoplasts with disrupted het-c2 genes, a condition previously linked to altered cell compatibility following hyphal fusion. The observed glycolipid transfer activity could not be accounted for by nonspecific lipid transfer protein activity. Direct assessment showed that purified, recombinant HET-C2 accelerates the intermembrane transfer of glycolipid in vitro, but that the HET-C2 activity is mitigated much less by negatively charged membranes than the mammalian glycolipid transfer protein. The findings are discussed within the context of HET-C2 being a member of an emerging family of ancestral sphingolipid transfer proteins that play important roles in cell proliferation and accelerated death.

Ascomycota↗

PubMed1999

Prion proteins carrying pathogenic mutations are resistant to phospholipase cleavage of their glycolipid anchors.

Familial prion diseases are linked to mutations in the gene encoding PrP, a protein of unknown function that is attached to the plasma membrane of neurons and several other cell types by a phosphatidylinositol-containing, glycolipid anchor. We have previously found that PrP molecules carrying disease-associated mutations display several biochemical attributes of PrPSc, the pathogenic isoform of PrP, when expressed in cultured Chinese hamster ovary cells. One of the distinctive properties of these mutant PrPs is their abnormal association with cell membranes, as revealed by their retention on the cell surface after treatment with a bacterial phospholipase that normally cleaves the glycolipid anchor. We demonstrate here that mutant PrP molecules, either expressed on intact cells or solubilized in nondenaturing detergents, are partially resistant to phospholipase cleavage. The anchor becomes fully susceptible to the enzyme when the proteins are denatured in SDS. These results suggest that the mutant PrP conformation, state of aggregation, or association with other molecules renders the glycolipid anchor physically inaccessible to cleavage. This conclusion stands in contrast to our previous suggestion that mutant PrP molecules are poorly released from the cell surface because they possess a secondary mechanism of membrane attachment in addition to the glycolipid anchor. Since PrPSc from scrapie-infected brain and cultured cells is also inefficiently released from membranes by phospholipase, resistance to this enzyme may be a molecular marker of the scrapie state.

Animals↗

PubMed2001

Comparative analysis of colonization of Helicobacter pylori and glycolipids receptor density in Mongolian gerbils and mice.

The Mongolian gerbil has been used as an excellent experimental animal model for studying Helicobacter pylori infection because it can stably colonize and induce severe chronic gastritis, ulceration, and cancer-simulating human diseases in this animal. In contrast, H. pylori can only induce mild inflammation in many mouse models. The aim in this study is to clarify the difference of induction of pathological lesions in the two animal models. SPF ICR mice and Mongolian gerbils were inoculated with a clinically isolated strain of H. pylori. Six weeks after inoculation, bacteria colonizing the stomach were counted. Immunohistochemical staining and biochemical analyses of three putative receptor glycolipids were performed with monoclonal antibodies to the respective glycolipids. Significantly higher numbers of H. pylori were recovered from the stomachs of Mongolian gerbils than mice (5.77 +/- 0.46 log CFU vs 4.17 +/- 0.55 log CFU, P < 0.01). Immunohistochemical studies showed that sulfatide expression in the gastric mucosa of Mongolian gerbils was much stronger than that in mice, whereas the expression of Lewis(b) glycolipid and GM3 were almost equal. Quantitative analysis of each glycolipid by thin-layer chromatography confirmed the results of immunohistochemical study, showing 4.1 times higher sulfatide content in the Mongolian gerbil stomach. The content of both Lewis(b) and GM3 was almost equivalent in these two animals. In conclusions, higher levels of sulfatide expression, a putative adhesion receptor, in the gastric mucosa of Mongolian gerbils may allow abundant colonization by H. pylori, resulting in the development of gastric lesions in this animal model.

Animals↗

PubMed1965

The glycolipids from the non-capsulated strain of Pneumococcus I-192R, A.T.C.C. 12213.

1. The total lipid was extracted from the non-capsulated strain of Pneumococcus I-192R, A.T.C.C. 12213, with chloroform-methanol mixtures. Two glycolipids were isolated by chromatography on silicic acid and DEAE-cellulose (acetate form). 2. The major glycolipid was obtained pure in a yield of 640mg./34g. dry wt. of cells and represents about 34% of the total lipid. It contained galactose, glucose, glycerol and fatty acid ester residues in the proportions 1:1:1:2, and yielded on saponification a crystalline non-reducing glycoside. 3. The structure of the glycoside was shown to be O-alpha-d-galactopyranosyl-(1-->2)-O-alpha-d-glucopyranosyl-(1-->1)-d-glycerol. The fatty acids obtained on saponification were identified by gas-liquid partition chromatography of their methyl esters. 4. The minor glycolipid was obtained as a 1:1 (w/w) mixture with the major component, but after saponification the two glycosides were separated by paper chromatography. Evidence was obtained for the structure of the glycoside derived from the minor glycolipid as 1-O-alpha-d-glucosylglycerol. 5. A general method is described for determining the stereochemistry of the glycerol moiety in 1-linked glycerol glycosides.

Journal Article↗

PubMed2003

Multifocal motor neuropathy caused by a B-cell lymphoma producing a monoclonal IgM autoantibody against peripheral nerve myelin glycolipids GM1 and GD1b.

Various data support the pathogenetic significance of serum IgM autoantibodies against glycolipid GM1 in patients with multifocal motor neuropathy. Although some patients with this neuropathy have an extraneural lymphoma, IgM anti-GM1 glycolipid autoantibodies have not been investigated in these cases. We found IgM anti-GM1 autoantibody in the serum of a 52-year-old man who developed multifocal motor neuropathy that was associated with an extraneural diffuse large B-cell lymphoma. An autopsy showed severe widespread demyelination without lymphoma cell infiltration in the peripheral nerves. Immunofluorescent flow cytometry and thin-layer chromatographic immunostaining demonstrated that most of the anti-GM1 antibody in the serum was monoclonal IgM of lambda type, which was also demonstrable in secretory form on lymphoma cells. The antibody showed affinity for the Galbeta1-3GalNAc terminal disaccharide of glycolipids GM1 and GD1b, which both are widespread in peripheral nerve myelin. Enzyme-linked immunosorbent assay demonstrated that this antibody was much more abundant in lymphoma cell culture supernatant than in normal lymphocyte culture supernatant. Thus, our patient's B-cell lymphoma cells produced a monoclonal IgM lambda autoantibody against this terminal disaccharide residue. This antibody bound to glycolipids GM1 and GD1b in peripheral motor nerve myelin, presumably initiating formation of destructive immune complexes that caused multifocal motor neuropathy.

Antigen-Antibody Complex↗

PubMed1999

NOR polyagglutination and Sta glycophorin in one family: relation of NOR polyagglutination to terminal alpha-galactose residues and abnormal glycolipids.

BACKGROUND: This report describes the characterization of polyagglutinable red cells (RBCs), identified in two generations of a Polish family. CASE REPORT: Untreated and modified RBCs of the proposita (TS) were tested by serologic methods, using human sera, antibodies, lectins, and inhibitors of agglutination. Moreover, glycophorins were characterized by sodium docecyl sulfate-polyacrylamide gel electrophoresis and Western blotting, and glycolipids were purified, fractionated by thin-layer chromatography, and detected with Ricinus communis agglutinin I (RCA-I, specific for galactose residues) and Griffonia simplicifolia IB4 lectin (GSL-IB4, specific for Gal alpha1-3Gal- structure). Some of the experiments were also performed on RBCs of members of TS's family. RESULTS: Polyagglutination, found in four members of TS's family, was identified as the second case of an earlier described NOR polyagglutination. The polyagglutination was decreased by treating the RBCs with alpha-galactosidase and was inhibited by a neutral glycolipid fraction from NOR+ RBCs. Detection of neutral glycolipids of TS's RBCs on the thin-layer plate by RCA-I and GSL-IB4 revealed the presence of components that were not detectable in control RBCs. Moreover, Western blotting of RBC membranes from five family members with glycophorin monoclonal antibodies and agglutination assays with anti-St(a) and anti-Dantu sera identified the presence of St(a) glycophorin in four members of the family, two of whom were NOR+ and two NOR-. CONCLUSION: Our results showed that two rare features of TS's RBCs, NOR polyagglutination and St(a) glycophorin, are inherited independently, and that NOR+ RBCs contain neutral glycolipids with an abnormal oligosaccharide structure, most likely terminated with alpha-galactosyl residues.

Adult↗

PubMed2004

Antiferroelectric ordering of amphiphilic glycolipids in bent-core liquid crystals.

Lipids are the main constituents of biological cell membranes, and their liquid crystalline properties play a crucial role in cell functions. We have discovered that dodecyl-beta-D-glucopyranoside glycolipid layers can be electrically polarized in supramolecular structures of glycolipid and bent-core ("banana-shape") molecules. Interestingly the glycolipid molecules, known to be excellent chiral dopants, are not able to transfer their chirality to the bent-core layers. Our observations indicate that glycolipid molecules self-assemble into pairs of tilted and antiferroelectric double layers, sandwiched between layers of bent-core molecules. These systems may provide a basis for understanding "bioferroelectricity," which is important in biological cell membrane functions.

Journal Article↗

PubMed1991

Detection of antibodies against glycolipids of Echinococcus multilocularis metacestodes in sera of patients with alveolar hydatid disease.

Glycosphingolipids extracted from Echinococcus multilocularis metacestodes were tested against sera from patients with alveolar hydatid disease (AHD). The tests were performed first by ELISA then by immunostaining on thin layer chromatography. A binding between the parasite glycolipids and antibodies of AHD human sera was observed by ELISA. The glycolipids related to this binding were specifically parasite neutral glycosphingolipids. No reaction was observed with parasite acid glycolipids nor with neutral glycolipid extracts from human or mongolian gerbil erythrocytes. Comparison between absorbance values of 25 AHD sera and 20 control sera showed significant differences. Similar results were obtained with sera from hydatid cyst patients. Sera from patients with other parasitoses (schistosomiasis, strongyloidosis or paludism) were also tested. The reactive fractions were identified by immunostaining on thin layer chromatography with AHD sera, they were neutral glycosphingolipids containing at least two carbohydrate residues. These results were compared with chromatograms obtained with hydatid cyst human sera and discussed.

Animals↗

PubMed2002

Inhibition of binding of Helicobacter pylori to the glycolipid receptors by probiotic Lactobacillus reuteri.

We examined the competition of binding of Lactobacillus reuteri and Helicobacter pylori to gangliotetraosylceramide (asialo-GM1) and sulfatide which are putative glycolipid receptor molecules of H. pylori, and identified a possible sulfatide-binding protein of the L. reuteri strain. Among nine L. reuteri strains, two (JCM1081 and TM105) were shown to bind to asialo-GM1 and sulfatide, and to inhibit binding of H. pylori to both glycolipids by a thin layer chromatogram-overlay assay using biotin-labeled bacterial cells. The extract from the bacterial cells of strain TM105 with several detergents, including octyl beta-D-glucopyranoside, retained binding to both glycolipids and also inhibited H. pylori binding, suggesting that a binding inhibitor(s) is associated with the bacterial cell surface. When the cell extract was applied to the agarose gel immobilized galactose 3-sulfate corresponding to the structure of sugar moieties of sulfatide, an approximately 47-kDa protein was found to bind to the gel. This observation strongly suggested that inhibition by selected L. reuteri strains help to prevent infection in an early stage of colonization in H. pylori and proposed that L. reuteri strains sharing glycolipid specificity with H. pylori have a potential as probiotics.

Animals↗

PubMed1990

Improved Method for the Isolation of Biosurfactant Glycolipids from Rhodococcus sp. Strain H13A.

An improved method for the isolation of the biosurfactant glycolipids from Rhodococcus sp. strain H13A by using XM 50 diafiltration and isopropanol precipitation was devised. This procedure was advantageous since it removes protein coisolated when the glycolipids are obtained by organic extraction and silicic acid chromatography. The protein apparently does not contribute any biosurfactant characteristics to the glycolipids. The deacylated glycolipid backbone included only a disaccharide.

Journal Article↗

PubMed1990

Modification of the glycolipid-binding specificity of vero cytotoxin by polymyxin B and other cyclic amphipathic peptides.

Polymyxin B, an amphipathic cyclic decapeptide produced by Bacillus polymyxa, is routinely used in the extraction of the components from the periplasmic space of gram-negative bacteria. Vero cytotoxin 1 (VT1) is an Escherichia coli-elaborated subunit toxin which binds to the glycolipid globotriosylceramide (Gal-alpha 1-4-Gal beta 1-4-Glc-ceramide [Gb3]) and has been strongly implicated in the etiology of the hemolytic uremic syndrome and hemorrhagic colitis. We now show by in vitro glycolipid-binding assays that in the presence of low concentrations of polymyxin B, globotetraosylceramide (GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc-ceramide [Gb4]) is also recognized by both the VT1 B (binding) subunit and holotoxin. Melittin, a 26-amino-acid cyclic peptide of similar amphipathic nature, produced the same effect, whereas a hydrophobic blocking agent did not. Triton X-100 did not increase binding of VT1 to Gb4 but prevented glycolipid binding in toto at concentrations above 0.5%. Caution is therefore advised in the analysis of VT1 glycolipid binding in the presence of amphipathic peptides.

Bacterial Toxins↗

PubMed1988

Characterization of a major neutral glycolipid in PC12 cells as III3Gal alpha-globotriaosylceramide by the method for determining glycosphingolipid saccharide sequence with endoglycoceramidase.

Neutral glycolipids in PC12 cells were examined. A major neutral glycosphingolipid, isolated from a chloroform/methanol extract of the cells, was found to contain only galactose and glucose at a ratio of 3:1 and identified as ceramide tetrahexoside by fast atom bombardment (FAB) mass spectrometry. Its saccharide sequence was determined by a new method developed here using endoglycoceramidase (Ito, M., and Yamagata, T. (1986) J. Biol. Chem. 261, 14278-14282). The glycosphingolipid was digested with endoglycoceramidase to produce oligosaccharide which was subsequently pyridylaminated. The fluorescence-labeled oligosaccharide was digested with a series of specific exoglycosidases and fractionated by high performance liquid chromatography. The 2-aminopyridyl oligosaccharide was hydrolyzed by alpha-galactosidase to give a 2-aminopyridyl oligosaccharide which was identified as 2-aminopyridyl lactose by high performance liquid chromatography, indicating the glycolipid structure to be Gal alpha Gal alpha Gal beta GlcCer. Ceramide trihexoside obtained by limited digestion of the intact glycolipid was clearly identical with ceramide trihexoside obtained from human erythrocytes, according to NMR spectroscopy and methylation analysis. From these and other data on the intact glycolipid, obtained by methylation analysis and NMR spectroscopy, its structure was confirmed as Gal alpha 1-3Gal alpha 1-4Gal beta 1-4Glc beta 1-1Cer, III3-Gal alpha-globotriaosylceramide. This is the first report indicating the presence of this glycosphingolipid in PC12 cells.

Adrenal Gland Neoplasms↗