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PubMed1993

Isolation and partial characterization of glycolipid fractions from Mycobacterium avium serovar 2 (Mycobacterium paratuberculosis 18) that inhibit activated macrophages.

Glycolipid fractions from Mycobacterium avium serovar 2 (Mycobacterium paratuberculosis 18) inhibited the killing of Candida albicans by activated bovine peripheral-blood-derived macrophages. Fractions were derived by using the matrix solid-phase dispersion technique, which is a new method of simultaneous lysis and partial fractionation of components of bacterial cells. Further purification of active fractions was performed by concanavalin A affinity chromatography, centrifugal filtration, and differing solvent solubility. Three different fractions were isolated and partially characterized. Two of these fractions have characteristics typical of glycolipids, and the third fraction has characteristics compatible with a peptidoglycolipid. This peptidoglycolipid fraction has been purified and named MIF-A3.

Acetonitriles↗
PubMed1973

Tissue receptor for cholera exotoxin: postulated structure from studies with GM1 ganglioside and related glycolipids.

By a double-diffusion precipitation-in-gel technique, isolated cholera toxin as well as its natural toxoid were shown to be fixed and precipitated by the ganglioside G(M1) but not by any of the related glycolipids G(M3), G(M2), G(M1)-GlcNAc, G(D1a), G(D1b), G(T1), globoside, G(A1), and tetrahexoside-GlcNAc. Twenty-five nanograms of G(M1) was enough to give a precipitation line with 1.2 mug of toxin, whereas about 50 ng was required with this amount of toxoid. G(M1) also inactivated the toxin in the ileal loop as well as in the intradermal models in rabbits. A 1: 1 molar ratio of ganglioside to toxin was found limiting, e.g., 100 pg of G(M1) could inactivate 5 ng (about 50 blueing doses) of isolated toxin. G(M1) inactivated crude toxin (culture fil rate) with the same efficiency as isolated toxin, and the inactivating capacity of G(M1) was unaffected by mixing with other gangliosides, indicating the specificity in the reaction between G(M1) and toxin. The other glycolipids tested did not inactivate toxin except G(D1a) and G(A1) which did so with approximately 1,000 times less efficiency than G(M1). This identified the portion Gal --> GalNAc [Formula: see text] as the critical region in G(M1) for toxin fixation, and it is postulated that this may be the tissue receptor structure for the cholera toxin.

Animals↗
PubMed1982

Glycolipids from some extreme thermophilic bacteria belonging to the genus Thermus.

The lipids of Thermus aquaticus YT1, Thermus thermophilus HB8, Thermus sp. strains H and J (from Icelandic hot springs), and Thermus sp. strain NH (from domestic hot water) have been investigated. Each strain contained two major components, a glycolipid and a glycophospholipid, which have been isolated and analyzed. All of the strains contained as the principal component (41 to 57% of total lipid) a diacyldiglycosyl-(N-acyl)glycosaminylglucosylglycerol, but the five glycolipids differed in carbohydrate composition. The glycophospholipid appeared to be identical in each strain and contained an N-acylglucosamine residue. The principal fatty acids were C15 and C17 branched-chain compounds. This unique polar lipid composition should be of value in the classification of other thermophiles in the genus Thermus. The exceptionally high carbohydrate content of the lipids of these extreme thermophiles may be of significance in relation to the molecular basis of thermophily.

Carbohydrates↗
PubMed1995

Carbohydrate-dependent binding of the cell-free hemagglutinin of Vibrio cholerae to glycoprotein and glycolipid.

The carbohydrate-binding specificity of the cell-free hemagglutinin (HA) of Vibrio cholerae (K.K. Banerjee, A.N. Ghose, K. Datta-Roy, S.C. Pal, and A.C. Ghose, Infect. Immun.58:3698-3705, 1990) was studied by using glycoconjugates with defined sugar sequences. The HA was not inhibited by simple sugars including glucobiose, galabiose, and their N-acetylated derivatives. The hemagglutination of rabbit erythrocytes by the HA was inhibited moderately by fetuin, calf thyroglobulin, and human alpha 1-acid glycoprotein, all of which contain multiple asparagine-linked complex-type oligosaccharide units alone or in combination with serine/threonine-linked oligosaccharide units. The inhibitory potencies of the glycoproteins increased approximately 10-fold following removal of the terminal sialic acid and were completely destroyed by exhausative proteolysis. The HA agglutinated phosphatidylcholine liposomes containing GM1-ganglioside or its asialo-derivative in the presence of Ca2+ ions. The association constants of the complexes of the HA with asialofetuin, asialothyroglobulin, GM1-ganglioside, and asialo-GM1-ganglioside were determined by an enzyme-linked immunosorbent assay-based assay and found to be 1.7 x 10(7) M-1, 1.5 x 10(7) M-1, 1.8 x 10(7) M-1, and 2.4 x 10(7) M-1, respectively. Studies using chemically modified glycoproteins and plant lectins with defined sugar specificity revealed that the HA recognized the terminal beta 1-galactosyl moiety of these glycoconjugates. There was no evidence for the presence of an extended carbohydrate-binding domain in the HA molecule or a preference of the HA for a complex, branched oligosaccharide structure. Similar to the mechanisms proposed for the binding of cholera toxin and Shiga toxin to glycolipids and neoglycoproteins, the strong interaction of V. cholerae cell-free HA with glycoconjugates appeared to be a consequence of multiple weak binding to terminal beta1-galactosyl moieties of the glycoproteins or glycolipids.

Animals↗
PubMed1987

Cellular and humoral immune response to a phenolic glycolipid antigen (PhenGL-I) in patients with leprosy.

The ability of phenolic glycolipid I (PhenGL-I) of Mycobacterium leprae to stimulate in vitro lymphocyte proliferation (LP) was tested in cultures of peripheral blood cells from 42 patients with leprosy in Chicago and Thailand, 9 individuals with household contact in Thailand, and 10 unexposed North American controls. Only 10 responders (24%) were found among the patients, and the degree of LP was small. Responders were found among patients with lepromatous (18%) or tuberculoid (30%) leprosy without relation to age, complications, duration of treatment, or lepromin responsiveness. The specificity of the response was supported by a lack of response to two other glycolipids, by responses by T cells but not B cells, and by the observation that three of four responders tested maintained their responses to PhenGL-I for at least 1 year. Serum immunoglobulin M (IgM) and IgG antibodies were measured in the same patients by using PhenGL-I or its terminal monosaccharide conjugated to a bovine serum albumin carrier in an enzyme-linked immunosorbent assay. The presence of IgM antibody correlated negatively with LP to lepromin and to PhenGL-I in patients with tuberculoid leprosy. We conclude that circulating T cells from some leprosy patients proliferate in the presence of PhenGL-I in vitro, but the response is weak, possibly due to concomitant suppression or inhibition. The predominance of IgM antibody to PhenGL-I may be related to a lack of a T-helper-cell-mediated switch to IgG antibody response.

Antibodies, Bacterial↗
PubMed1989

Oligomerization of glycolipid-anchored and soluble forms of the vesicular stomatitis virus glycoprotein.

The vesicular stomatitis virus glycoprotein forms noncovalently linked trimers in the endoplasmic reticulum before being transported to the Golgi apparatus. The experiments reported here were designed to determine if the extracellular domain of the glycoprotein contains structural information sufficient to direct trimer formation. To accomplish this, we generated a construct encoding G protein with the normal transmembrane and anchor sequences replaced with the sequence encoding 53 C-terminal amino acids from the Thy-1.1 glycoprotein. We show here that these sequences were able to specify glycolipid addition to the truncated G protein, probably after cleavage of 31 amino acids derived from Thy-1.1. The glycolipid-anchored G protein formed trimers and was expressed on the cell surface in a form that could be cleaved by phosphoinositol-specific phospholipase C. However, the rate of transport was reduced, compared with that of wild-type G protein. A second form of the G protein was generated by deletion of only the transmembrane and cytoplasmic domains. This mutant protein also formed trimers with relatively high efficiency and was secreted slowly from cells.

Acetylglucosaminidase↗
PubMed1971

Glycolipid content of vesicular stomatitis virus grown in baby hamster kidney cells.

Vesicular stomatitis virions grown in baby hamster kidney (BHK-21-F) cells were found to contain hematoside (neuraminosyl-galactosyl-glucosyl-ceramide). This ganglioside, which was the only detectable glycolipid in the virion, is also the only glycolipid found in significant amount in BHK-21-F cells. Approximately 87% of the total neuraminic acid in the virion was found to be linked to protein and 13% to lipid.

Animals↗
PubMed1991

Anchoring and degradation of glycolipid-anchored membrane proteins by L929 versus by LM-TK- mouse fibroblasts: implications for anchor biosynthesis.

Although many cells anchor surface proteins via moieties that are sensitive to phosphatidylinositol-specific phospholipase C (PI-PLC), the anchor moieties of surface proteins of mouse L929 cells resist PI-PLC. By constructing stable hybrids between L929 and lymphoma cells that express glycolipid-anchored proteins in a PI-PLC-sensitive form, we show that PI-PLC resistance behaves as a recessive trait. Since putative mannolipid precursors of the lipid anchors bear alkali-labile substituents which make them resist PI-PLC, these observations are most simply interpreted by postulating that L929 lacks a critical anchor deacylase. Unlike the L929 cell line, two of its descendants, the LM cell line and its thymidine kinase-negative variant (LM-TK-), do not express glycolipid-anchored proteins on their surface. Moreover, unlike L929 cells, LM-TK- cells rapidly inactivate at least one lipid-anchored enzyme in a compartment sensitive to acidotropic amines and leupeptin. By fusion of LM-TK- cells to mouse Thy-1- lymphoma mutants and monitoring of surface expression of lipid-anchored proteins, we assign LM-TK- to lymphoma mutant complementation group H. This genetic assignment is matched by analysis of mannolipids of L929, LM-TK-, wild-type, and class H lymphoma mutant cells: striking similarities are seen between the two wild-type cells by contrast to the mutants. Since the differences pertain to lipids which have properties consistent with their being anchor precursors, we suggest that LM-TK- has a lesion in the synthesis of anchor precursor mannolipids.

Alkaline Phosphatase↗
PubMed1990

Serum immunoglobulins to endotoxin core glycolipid: acute leukaemia and other cancers.

Circulating antibody to endotoxin core glycolipid and total serum immunoglobulin concentrations were measured in 86 children with cancer (54 with acute lymphoblastic leukaemia, four with acute myeloid leukaemia, and 28 with various solid tumours). Measurements were made before treatment in the group with acute lymphoblastic leukaemia as well as when patients were both on and off chemotherapy. In the other two groups measurements were made when patients were both on and off treatment. Significant reductions in endotoxin antibody and serum immunoglobulin concentrations were found only in patients with acute lymphoblastic leukaemia. In addition, there was a significant correlation between febrile episodes and the concentration of antibody to core glycolipid in the children with acute lymphoblastic leukaemia. These findings suggest that the use of prophylactic high titre endotoxin antibody may be of benefit to children with life threatening Gram negative infections who are receiving cytotoxic chemotherapy.

Child↗
PubMed1998

A unique familial leukodystrophy with adult onset dementia and abnormal glycolipid storage: a new lysosomal disease?

Two adult siblings with early onset dementia are described. At presentation, in their early 30s, they showed poor judgment and disinhibition. A progressive dementia ensued over several years. Brain MRI disclosed diffusely increased T2 signal in the cerebral white matter, suggestive of a leukodystrophy. Numerous lysosomal enzyme assays including leucocyte arylsulphatase A and galactocerebrosidase activities, plasma and fibroblast very long chain fatty acid concentrations, and urinary sulphatide concentrations were normal, as were CSF analyses. A brain biopsy disclosed periodic acid Schiff (PAS) and Sudan black positive material in perivascular macrophages which, by electron microscopy, consisted of stacks of straight or curvilinear paired membranes within angulate lysosomes, indicative of abnormal glycolipid accumulation. The combination of clinical, radiological, biochemical, and pathological features of this degenerative disease is not consistent with that of any of the known leukodystrophies or lysosomal storage disorders. These findings suggest a previously undescribed familial glycolipid storage disorder causing an adult onset leukodystrophy and presenting with behavioural symptoms that mimic a psychiatric disorder.

Adult↗
PubMed1999

The CD1 system: antigen-presenting molecules for T cell recognition of lipids and glycolipids.

Recent studies have identified the CD1 family of proteins as novel antigen-presenting molecules encoded by genes located outside of the major histocompatibility complex. CD1 proteins are conserved in all mammalian species so far examined and are prominently expressed on cells involved in antigen presentation, which suggests a role in activation of cell-mediated immunity. This has now been confirmed by functional studies demonstrating the ability of CD1 proteins to restrict the antigen-specific responses of T cells in humans and mice. Identification of naturally occurring antigens presented by CD1 has revealed the surprising finding that these are predominantly a variety of foreign lipids and glycolipids, including several found prominently in the cell walls and membranes of pathogenic mycobacteria. Structural, biochemical, and biophysical studies support the view that CD1 proteins bind the hydrophobic alkyl portions of these antigens directly and position the polar or hydrophilic head groups of bound lipids and glycolipids for highly specific interactions with T cell antigen receptors. Presentation of antigens by CD1 proteins requires uptake and intracellular processing by antigen presenting cells, and evidence exists for cellular pathways leading to the presentation of both exogenous and endogenous lipid antigens. T cells recognizing antigens presented by CD1 have a range of functional activities that suggest they are likely to mediate an important component of antimicrobial immunity and may also contribute to autoimmunity and host responses against neoplastic cells.

Animals↗
PubMed2000

Accessibility of glycolipid and oligosaccharide epitopes on rabbit villus and follicle-associated epithelium.

The initial step in many mucosal infections is pathogen attachment to glycoconjugates on the apical surfaces of intestinal epithelial cells. We examined the ability of virus-sized (120-nm) and bacterium-sized (1-microm) particles to adhere to specific glycolipids and protein-linked oligosaccharides on the apical surfaces of rabbit Peyer's patch villus enterocytes, follicle-associated enterocytes, and M cells. Particles coated with the B subunit of cholera toxin, which binds the ubiquitous glycolipid GM1, were unable to adhere to enterocytes or M cells. This confirms that both the filamentous brush border glycocalyx on enterocytes and the thin glycoprotein coat on M cells can function as size-selective barriers. Oligosaccharides containing terminal beta(1,4)-linked galactose were accessible to soluble lectin Ricinus communis type I on all epithelial cells but were not accessible to lectin immobilized on beads. Oligosaccharides containing alpha(2, 3)-linked sialic acid were recognized on all epithelial cells by soluble Maackia amurensis lectin II (Mal II). Mal II coated 120-nm (but not 1-microm) particles adhered to follicle-associated enterocytes and M cells but not to villus enterocytes. The differences in receptor availability observed may explain in part the selective attachment of viruses and bacteria to specific cell types in the intestinal mucosa.

Animals↗
PubMed1988

Nephrotic syndrome and renal failure associated with a novel glycolipid storage disorder.

A 57-year-old Caucasian male presented with severe nephrotic syndrome and diffuse organomegaly; he subsequently developed renal failure and died. Intracellular, crystalloid material was identified by light and electron microscopy in bone marrow, liver, spleen, mesenteric lymph nodes, and kidneys. Tissue extraction analysis identified the material as glucocerebroside and its immediate precursor, ceramide lactoside. Although Gaucher's disease cannot be completely excluded, glycolipid profiles do not conform to those of known storage disorders. Additionally, electron-microscopic studies indicate that the structural features of the glycolipid deposits are different from those of previously described storage diseases. These findings suggest a unique crystalloid deposition as the probable cause of a multisystem process, which was associated with renal insufficiency and death.

Acute Kidney Injury↗
PubMed2005

Stimulation of liver-directed cholesterol flux in mice by novel N-acetylgalactosamine-terminated glycolipids with high affinity for the asialoglycoprotein receptor.

OBJECTIVE: Interventions that promote liver-directed cholesterol flux can suppress atherosclerosis, as demonstrated for scavenger receptor-BI overexpression in hypercholesterolemic mice. In analogy, we speculate that increasing lipoprotein flux to the liver via the asialoglycoprotein receptor (ASGPr) may be of therapeutic value in hypercholesterolemia. METHODS AND RESULTS: A bifunctional glycolipid (LCO-Tyr-GalNAc3) with a high-nanomolar affinity for the ASGPr (inhibition constant 2.1+/-0.2 nmol/L) was synthesized that showed rapid association with lipoproteins on incubation with serum. Prior incubation of LCO-Tyr-GalNAc3 with radiolabeled low-density lipoprotein or high-density lipoprotein (0.5 microg/microg of protein) resulted in a dramatic induction of the liver uptake of these lipoproteins when injected intravenously into mice (70+/-3% and 78+/-1%, respectively, of the injected dose at 10 minutes of low-density lipoprotein and high-density lipoprotein), as mediated by the ASGPr on hepatocytes. Intravenously injected LCO-Tyr-GalNAc3 quantitatively incorporated into serum lipoproteins and evoked a strong and persistent (> or =48 hour) cholesterol-lowering effect in normolipidemic mice (37+/-2% at 6 hours) and hyperlipidemic apoE(-/-) mice (32+/-2% at 6 hours). The glycolipid was also effective on subcutaneous administration. CONCLUSIONS: LCO-Tyr-GalNAc3 is very effective in promoting cholesterol uptake by hepatocytes and, thus, may be a promising alternative for the treatment of those hyperlipidemic patients who do not respond sufficiently to conventional cholesterol-lowering therapies.

Acetylgalactosamine↗
PubMed1989

Anti-peripheral nerve myelin antibodies in Guillain-Barre syndrome bind a neutral glycolipid of peripheral myelin and cross-react with Forssman antigen.

During acute-phase illness, serum of patients with Guillain-Barre syndrome (GBS) contain complement-fixing antibodies (Ab) to peripheral nerve myelin (PNM). We investigated PNM lipids as putative antigens for these Ab since GBS serum retained significant reactivity to PNM treated with protease. Ab binding to specific lipids was studied with a C1 fixation and transfer (C1FT) assay using fractions of PNM lipid reincorporated into liposomes as antigen targets or to lipids on HPTLC plates with peroxidase-labeled goat Ab to human IgM. Reactivity was detected to a neutral glycolipid (NGL) of human PNM with a similar number of carbohydrates residues to that of Forssman hapten (Forss). Anti-NGL Ab titers in GBS patients (50-220 U/ml) were significantly elevated over disease and normal controls (0-5 and 0-6 U/ml). We studied possible antigenic cross-reactivity of these Ab with Forss by first quantitating Ab activity with C1FT assay and liposomes containing Forss. All 12 GBS sera tested showed titers (54-272 U/ml) significantly elevated over 11 disease controls (0-22 U/ml) and 25 normal controls (0-11 U/ml). GBS serum Ab reacted with Forss isolated from dog nerve or sheep erythrocytes on HPTLC plates. Further, absorption of 80-100% of anti-NGL Ab activity and 17-97% of anti-PNM Ab activity from eight GBS patient serums was accomplished with liposomes containing Forss but not with control liposomes. In seven GBS patients anti-NGL Ab activity represented only a portion of anti-PNM Ab activity. These results suggest that a glycolipid with antigenic cross-reactivity to Forssman hapten may be responsible for some of the anti-PNM Ab activity in GBS.

Antibodies↗
PubMed2004

The clinical implication and molecular mechanism of preferential IL-4 production by modified glycolipid-stimulated NKT cells.

OCH, a sphingosine-truncated analog of alpha-galactosylceramide (alphaGC), is a potential therapeutic reagent for a variety of Th1-mediated autoimmune diseases through its selective induction of Th2 cytokines from natural killer T (NKT) cells. We demonstrate here that the NKT cell production of IFN-gamma is more susceptible to the sphingosine length of glycolipid ligand than that of IL-4 and that the length of the sphingosine chain determines the duration of NKT cell stimulation by CD1d-associated glycolipids. Furthermore, IFN-gamma production by NKT cells requires longer T cell receptor stimulation than is required for IL-4 production by NKT cells stimulated either with immobilized mAb to CD3 or with immobilized "alphaGC-loaded" CD1d molecules. Interestingly, transcription of IFN-gamma but not that of IL-4 was sensitive to cycloheximide treatment, indicating the intrinsic involvement of de novo protein synthesis for IFN-gamma production by NKT cells. Finally, we determined c-Rel was preferentially transcribed in alphaGC-stimulated but not in OCH-stimulated NKT cells and was essential for IFN-gamma production by activated NKT cells. Given the dominant immune regulation by the remarkable cytokine production of ligand-stimulated NKT cells in vivo, in comparison with that of (antigen-specific) T cells or NK cells, the current study confirms OCH as a likely therapeutic reagent for use against Th1-mediated autoimmune diseases and provides a novel clue for the design of drugs targeting NKT cells.

Animals↗
PubMed2006

Mutation of beta-glucosidase 2 causes glycolipid storage disease and impaired male fertility.

beta-Glucosidase 2 (GBA2) is a resident enzyme of the endoplasmic reticulum thought to play a role in the metabolism of bile acid-glucose conjugates. To gain insight into the biological function of this enzyme and its substrates, we generated mice deficient in GBA2 and found that these animals had normal bile acid metabolism. Knockout males exhibited impaired fertility. Microscopic examination of sperm revealed large round heads (globozoospermia), abnormal acrosomes, and defective mobility. Glycolipids, identified as glucosylceramides by mass spectrometry, accumulated in the testes, brains, and livers of the knockout mice but did not cause obvious neurological symptoms, organomegaly, or a reduction in lifespan. Recombinant GBA2 hydrolyzed glucosylceramide to glucose and ceramide; the same reaction catalyzed by the beta-glucosidase acid 1 (GBA1) defective in subjects with the Gaucher's form of lysosomal storage disease. We conclude that GBA2 is a glucosylceramidase whose loss causes accumulation of glycolipids and an endoplasmic reticulum storage disease.

Animals↗
PubMed1986

Lectin histochemistry of glycolipid storage diseases on frozen and paraffin-embedded tissue sections.

Lectin histochemical studies were performed on frozen and paraffin-embedded brain tissue sections from six cases of galactosylceramide lipidosis (i.e., globoid cell leukodystrophy, or Krabbe's disease) in Twitcher mice and one case of canine infantile GM1-gangliosidosis. The globoid cells in Krabbe's disease stained with Ricinus communis agglutinin-I (RCA-I), peanut agglutinin (PNA), and Bandeirea simplicifolia agglutinin-I (BS-I) in frozen sections. However, paraffin sections and frozen sections pretreated with chloroform-methanol or xylene, from the same animals, stained with Concanavlia ensiformis agglutinin (ConA), wheat germ agglutinin (WGA), and succinylated-WGA (S-WGA), in addition to staining with RCA-I, PNA, and BS-I. The affected neurons of canine infantile GM1-gangliosidosis stained only with RCA-I in frozen sections. In paraffin sections, however, these cells were negative with RCA-I but positive with BS-I, ConA, Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA) and Ulex europaeus agglutinin (UEA-I) in paraffin sections. These results indicate that in paraffin processing of glycolipid storage disease tissue, some lectin receptors are lost and others are unmasked. The retained receptors can be stained with specific lectins and could serve as markers to characterize and differentiate among the various glycolipid storage diseases.

Animals↗