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Gangliosides
Kinds of Gangliosides Terms modified by Gangliosides Selected AbstractsGanglioside GD3 expression on target cells can modulate NK cell cytotoxicity via siglec-7-dependent and -independent mechanismsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2003Gavin Nicoll Abstract Siglec-7 is a sialic acid binding receptor with inhibitory potential, expressed on human NK cells and monocytes. It has an unusual binding preference for ,2,8-linked disialic acids, such as those displayed by ganglioside GD3. Here we have investigated whether siglec-7-GD3 interactions are able to modulate NK cell cytotoxicity. Using synthetic polyacrylamide glycoprobes, siglec-7 was found to be masked at the NK cell surface but it could be unmasked by sialidase treatment of NK cells. GD3 synthase-transfected P815 target cells expressed high levels of GD3 and bound strongly to recombinant siglec-7-Fc protein. Surprisingly, GD3 synthase-transfected P815 cells were killed more effectively by untreated cells in a siglec-7-independent manner. However, following sialidase treatment of NK cells, a siglec-7-dependent inhibition of killing was observed. These findings have important implications for NK cell cytotoxicity against tumor cells like melanoma that express high levels of GD3 ganglioside. [source] Characterization of Xenopus egg membrane microdomains containing uroplakin Ib/III complex: roles of their molecular interactions for subcellular localization and signal transductionGENES TO CELLS, Issue 2 2007A.K.M. Mahbub Hasan A single-transmembrane protein uroplakin III (UPIII) and its tetraspanin binding-partner uroplakin Ib (UPIb) are members of the UP proteins that were originally identified in mammalian urothelium. In Xenopus laevis eggs, these proteins: xUPIII and xUPIb, are components of the cholesterol-enriched membrane microdomains or "rafts" and involved in the sperm,egg membrane interaction and subsequent egg activation signaling via Src tyrosine kinase at fertilization. Here, we investigate whether the xUPIII-xUPIb complex is in close proximity to CD9, a tetraspanin that has been implicated in the sperm,egg fusion in the mouse and GM1, a ganglioside typically enriched in egg rafts. Preparation of the egg membrane microdomains using different non-ionic detergents (Brij 98 and Triton X-100), chemical cross-linking, co-immunoprecipitation, in vitro kinase assay and in vitro fertilization experiments demonstrated that GM1, but not CD9, is in association with the xUPIII-xUPIb complex and contributes to the sperm-dependent egg activation. Transfection experiments using HEK293 cells demonstrated that xUPIII and xUPIb localized efficiently to the cholesterol-dependent membrane microdomains when they were co-expressed, whereas co-expression of xUPIII and CD9, instead of xUPIb, did not show this effect. Furthermore, xUPIII and xUPIb were shown to suppress kinase activity of the wild type, but not a constitutively active form of, Xenopus Src protein co-expressed in HEK293 cells. These results provide novel insight into the molecular architecture of the egg membrane microdomains containing xUPIII, xUPIb and Src, which may contribute to the understanding of sperm,egg interaction and signaling during Xenopus fertilization. [source] A sialylation study of mouse brain gangliosides by MALDI a-TOF and o-TOF mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2008Mostafa Zarei Abstract Matrix-assisted laser desorption/ionization (MALDI) process of sialoglycoconjugates is generally accompanied by different levels of cleavage of sialic acid residues and/or by dehydration, and decarboxylation reactions. Quantitative densitometry of the mouse brain ganglioside (MBG) components separated by high-performance thin layer chromatography (HPTLC) and evidenced by orcinol staining was a basis to verify the ganglioside composition pattern with respect to the relative abundances of individual components in the mixture. A systematic mass spectrometry (MS) sialylation analysis has been carried out to evaluate the feasibility of an axial time-of-flight (a-TOF) MS, equipped with a vacuum MALDI source and an orthogonal-TOF (o-TOF) instrument with an ion source operated at about 1 mbar of N2. Besides, the esterification by one methyl group of the carboxyl group in sialic acid to increase the stability of the ganglioside species for MALDI MS analysis has been tested and the yield of intact ganglioside species and of the neutral loss of water and carbon dioxide estimated. For the sialylation analysis of native ganglioside mixtures the MALDI o-TOF analysis with 6-azo-2-thiothymine/diammonium citrate (ATT/DAC) as a matrix appears as an optimal approach for ganglioside profiling. Copyright © 2008 John Wiley & Sons, Ltd. [source] Accelerated release of exosome-associated GM1 ganglioside (GM1) by endocytic pathway abnormality: another putative pathway for GM1-induced amyloid fibril formationJOURNAL OF NEUROCHEMISTRY, Issue 1 2008Kohei Yuyama Abstract Exosomes are extracellularly released small vesicles that are derived from multivesicular bodies formed via the endocytic pathway. We treated pheochromocytoma PC12 cells with chloroquine, an acidotropic agent, which potently perturbs membrane trafficking from endosomes to lysosomes. Chloroquine treatment increased the level of GM1 ganglioside in cell media only when the cells were exposed to KCl for depolarization, which is known to enhance exosome release from neurons. In the sucrose-density-gradient fractionation of cell media, GM1 ganglioside was exclusively recovered with Alix, a specific marker of exosomes, in the fractions with the density corrresponding to that of exosomes. Notably, amyloid-, assembly was markedly accelerated when incubated with the exosome fraction prepared from the culture media of PC12 cells treated with chloroquine and KCl. Furthermore, amyloid-, assembly was significantly suppressed by the co-incubation with an antibody specific to GM1-bound amyloid-,, an endogenous seed for amyloid formation of Alzheimer's disease. Together with our previous finding that chloroquine treatment induces the accumulation of GM1 ganglioside in early endosomes, results of this study suggest that endocytic pathway abnormality accelerates the release of exosome-associated GM1 ganglioside following its accumulation in early endosomes. Furthermore, this study also suggests that extracellular amyloid fibril formation is induced by not only GM1 gangliosides accumulated on the surface of the cells but also those released in association with exosomes. [source] Effects of ethanol on gangliosides in the plasma, liver, and brain of inbred mouse strainsJOURNAL OF NEUROCHEMISTRY, Issue 2002M. I. Saito The mouse inbred strains C57BL/6ByJ and BALB/cJ show genetically different alcohol-related behaviors. Using these strains, we examined ganglioside contents in the plasma, liver, and brain with or without acute ethanol treatment. The quantification of GM1 was performed with a TLC-immunostaining procedure using choleragenoid, and the contents of other gangliosides were measured after staining with resorcinol reagents. It is known that there are polymorphisms in ganglioside compositions among inbred mouse strains. We found that the plasma GM1 level in BALB/cJ mice (1.6 ± 0.6 ng/,L) was 12 times higher than the level found in C57BL/6ByJ mice (0.13 ± 0.03 ng/,L) although the major ganglioside in both strains was GM2. The ganglioside profiles in the liver were similar to those of the plasma, and the GM1 level in BALB/cJ was 25 times higher than that of C57BL/6ByJ. The liver probably synthesizes the plasma gangliosides as suggested in other studies. The total brain ganglioside compositions were also different between BALB/cJ and C57BL/6ByJ. The levels of GD1b and GQ1b were higher in BALB/cJ although the GM1 contents were similar. These animals were injected with 20% ethanol intraperitoneally in a single dose of 3 g/kg and the ganglioside contents were measured after 4 h. The GM1 levels in the liver and plasma were lower in ethanol-treated animals while the GM1 levels were higher in erythrocytes and brains. Since it has been shown that the administration of GM1 attenuates or modifies the effects of ethanol in several animal models, the difference in GM1 contents in the plasma between BALB/cJ and C57BL/6ByJ may contribute to some of the differences in ethanol-related behaviors or toxicity between these strains. [source] Identification of a GM1/Sodium,Calcium exchanger complex in the nuclear envelope of non-neuronal cellsJOURNAL OF NEUROCHEMISTRY, Issue 2002X. Xie Our previous studies identified a Na,Ca exchanger (NCX) that is tightly associated with GM1 ganglioside and potentiated by it in the nuclear envelope (NE) of NG108-15 cells and primary neurons. The purpose of the present study was to explore whether this is a general phenomena or limited to neurons. Non-neuronal C6 (glioma), HeLa (Epithelial carcinoma) and NCTC (connective tissue) cell lines were used. Immunocytochemical staining with anti-NCX antibody and cholera toxin B subunit revealed that NCX and GM1 coexist in the nuclei from all 3 cell lines; in relation to plasma membrane, only HeLa cells showed staining for both NCX and GM1. Purified NE and non-nuclear membrane mixture (mainly plasma membrane) from the 3 cell lines were immunoprecipitated with a mouse monoclonal anti-NCX antibody and the precipitated proteins separated on SDS,PAGE. Analysis by immunoblot, showed that NCX is tightly associated with GM1 in the NE of all 3 cell lines. In contrast, NCX and the more loosely associated GM1 from plasma membrane of HeLa cells were separated by SDS,PAGE. Isolated nuclei from C6 cells were used for 45Ca2+ uptake experiments, which provided functional evidence that this exchanger protein is strongly potentiated by GM1. In similar experiments with Jurkat cells (T lymphocyte), no NCX was found. These results suggest a possible new and widely distributed mechanism for regulation of nuclear calcium by NCX in association with GM1. Acknowledgements:, supported by NIH grant NS 33912. [source] Glial-guided neuronal migration in P19 embryonal carcinoma stem cell aggregatesJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2005Marcelo F. Santiago Abstract During development of the nervous system, neuronal precursors that originated in proliferative regions migrate along radial glial fibers to reach their final destination. P19 embryonal carcinoma (EC) stem cells exposed to retinoic acid (RA) differentiate into neurons, glia, and fibroblast-like cells. In this work, we induced P19 aggregates for 4 days with RA and plated them onto tissue culture dishes coated with poly-L-lysine. Several cells migrated out of and/or extended processes from the aggregates after 24 hr. Some cell processes were morphologically similar to radial glial fibers and stained for glial fibrillar acidic protein (GFAP) and nestin. Large numbers of migrating cells showed characteristics similar to those of bipolar migrating neurons and expressed the neuronal marker microtubule-associated protein 2. Furthermore, scanning electron microscopy analysis revealed an intimate association between the radial fibers and the migrating cells. Therefore, the migration of neuron-like cells on radial glia fibers in differentiated P19 aggregates resembled some of the migration models used thus far to study gliophilic neuronal migration. In addition, HPTLC analysis in this system showed the expression of 9-O-acetyl GD3, a ganglioside that has been associated with neuronal migration. Antibody perturbation assays showed that immunoblockage of 9-O-acetyl GD3 arrested neuronal migration in a reversible manner. In summary, we have characterized a new cell culture model for investigation of glial-guided neuronal migration and have shown that 9-O-acetyl GD3 ganglioside has an important role in this phenomenon. © 2005 Wiley-Liss, Inc. [source] Structure Of Campylobacter Jejuni Lipopolysaccharides Determines Antiganglioside Specificity And Clinical Features Of Guillain-Barre, And Miller Fisher PatientsJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2002CW Ang Ganglioside mimicry in the lipopolysaccharide (LPS) fraction of Campylobacter jejuni isolated from Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) patients was compared with isolates from patients with an uncomplicated enteritis. The antibody response to C. jejuni LPS and gangliosides in neuropathy patients and controls was compared as well. LPS from GBS and MFS-associated isolates more frequently contained ganglioside-like epitopes compared to control isolates. Almost all neuropathy patients showed a strong antibody response against LPS and multiple gangliosides in contrast to enteritis patients. Isolates from GBS patients more frequently had a GM1-like epitope than isolates from MFS patients. GQ1b-like epitopes were present in all MFS-associated isolates and was associated with anti-GQ1b antibody reactivity and the presence of oculomotor symptoms. These results demonstrate that the expression of ganglioside mimics is a risk factor for the development of post-Campylobacter neuropathy. This study provides additional evidence for the hypothesis that the LPS fraction determines the antiganglioside specificity and clinical features in post-Campylobacter neuropathy patients. [source] Sialic Acid Engineering of Thin Hydrogel MembranesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2007Stéphane Woerly Abstract We report the synthesis of glycosylated hydrogel membranes of poly{[N -(2-hydroxypropyl)methacrylamide]- co -(2-hydroxyethyl methacrylate)} with the aim of developing bioactivated polymer substrates for cell culture. 3,-Sialyllactose, the saccharidic portion of the GM3 ganglioside involved in cell-cell recognition over a wide range of biological processes, was chemically modified with an acrylate group and incorporated into the growing macromolecular network of hydrogels by free radical crosslinking copolymerization. The incorporation and accessibility of the sialic acid residues at the hydrogel surface was verified by enzyme linked immunosorbent assay using mouse monoclonal anti-GM3, and by electron microscopy after labeling with lectin-gold nanoparticles. The water content was further characterized by thermogravimetry. [source] Ganglioside mimicry and peripheral nerve diseaseMUSCLE AND NERVE, Issue 6 2007Nobuhiro Yuki MD Abstract Four criteria must be satisfied to conclude that a given microorganism causes Guillain,Barré (GBS) or Fisher (FS) syndrome associated with anti-ganglioside antibodies: (1) an epidemiological association between the infecting microbe and GBS or FS; (2) isolation in the acute progressive phase of illness of that microorganism from GBS or FS patients with associated anti-ganglioside IgG antibodies; (3) identification of a microbial ganglioside mimic; and (4) a GBS or FS with associated anti-ganglioside antibodies model produced by sensitization with the microbe itself or its component, as well as with ganglioside. Campylobacter jejuni is a definitive causative microorganism of acute motor axonal neuropathy and may cause FS and related conditions. Haemophilus influenzae and Mycoplasma pneumoniae are possible causative microorganisms of acute motor axonal neuropathy or FS. Acute and chronic inflammatory demyelinating polyneuropathies may be produced by mechanisms other than ganglioside mimicry. Muscle Nerve, 2007 [source] Biochemical and immunological characterization of the plant-derived candidate human immunodeficiency virus type 1 mucosal vaccine CTB,MPR649,684PLANT BIOTECHNOLOGY JOURNAL, Issue 2 2009Nobuyuki Matoba Summary Plants are potentially the most economical platforms for the large-scale production of recombinant proteins. Thus, plant-based expression of subunit human immunodeficiency virus type 1 (HIV-1) vaccines provides an opportunity for their global use against the acquired immunodeficiency syndrome pandemic. CTB,MPR649,684[CTB, cholera toxin B subunit; MPR, membrane proximal (ectodomain) region of gp41] is an HIV-1 vaccine candidate that has been shown previously to induce antibodies that block a pathway of HIV-1 mucosal transmission. In this article, the molecular characterization of CTB,MPR649,684 expressed in transgenic Nicotiana benthamiana plants is reported. Virtually all of the CTB,MPR649,684 proteins expressed in the selected line were shown to have assembled into pentameric, GM1 ganglioside-binding complexes. Detailed biochemical analyses on the purified protein revealed that it was N- glycosylated, predominantly with high-mannose-type glycans (more than 75%), as predicted from a consensus asparagine,X,serine/threonine (Asn-X-Ser/Thr) N- glycosylation sequon on the CTB domain and an endoplasmic reticulum retention signal attached at the C-terminus of the fusion protein. Despite this modification, the plant-expressed protein retained the nanomolar affinity to GM1 ganglioside and the critical antigenicity of the MPR649,684 moiety. Furthermore, the protein induced mucosal and serum anti-MPR649,684 antibodies in mice after mucosal prime-systemic boost immunization. Our data indicate that plant-based expression can be a viable alternative for the production of this subunit HIV-1 vaccine candidate. [source] Neurotrophic effects of GM1 ganglioside and electrical stimulation on cochlear spiral ganglion neurons in cats deafened as neonatesTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 6 2007Patricia A. Leake Abstract Previous studies have shown that electrical stimulation of the cochlea by a cochlear implant promotes increased survival of spiral ganglion (SG) neurons in animals deafened early in life (Leake et al. [1999] J Comp Neurol 412:543,562). However, electrical stimulation only partially prevents SG degeneration after deafening and other neurotrophic agents that may be used along with an implant are of great interest. GM1 ganglioside is a glycosphingolipid that has been reported to be beneficial in treating stroke, spinal cord injuries, and Alzheimer's disease. GM1 activates trkB signaling and potentiates neurotrophins, and exogenous administration of GM1 has been shown to reduce SG degeneration after hearing loss. In the present study, animals were deafened as neonates and received daily injections of GM1, beginning either at birth or after animals were deafened and continuing until the time of cochlear implantation. GM1-treated and deafened control groups were examined at 7,8 weeks of age; additional GM1 and no-GM1 deafened control groups received a cochlear implant at 7,8 weeks of age and at least 6 months of unilateral electrical stimulation. Electrical stimulation elicited a significant trophic effect in both the GM1 group and the no-GM1 group as compared to the contralateral, nonstimulated ears. The results also demonstrated a modest initial improvement in SG density with GM1 treatment, which was maintained by and additive with the trophic effect of subsequent electrical stimulation. However, in the deafened ears contralateral to the implant SG soma size was severely reduced several months after withdrawal of GM1 in the absence of electrical activation. J. Comp. Neurol. 501:837,853, 2007. © 2007 Wiley-Liss, Inc. [source] Reduction of oxidative changes in human spermatozoa by exogenous gangliosidesANDROLOGIA, Issue 1 2005M. Gavella Summary The effect of exogenous gangliosides, the sialic acid-containing glycosphingolipids, on oxidative changes in human spermatozoa was investigated. The incorporation of disialogangliosides or trisialogangliosides (GD1b and GT1b, respectively) into the iron/ascorbate promoter system for induction of lipid peroxidation decreased the release of malondialdehyde (MDA) from peroxidizing spermatozoa. The application of monosialogangliosides and disialogangliosides (GM1 and GD1a, respectively) did not have any effect under identical experimental conditions. GT1b, at a micromolar concentration, significantly inhibited the production of MDA, a breakdown product of lipid peroxide decomposition in spermatozoa of normozoospermic infertile men (P < 0.001; n = 51). An enhanced generation of MDA exhibited by the sperm population from the low-density Percoll fraction containing defective and/or immature spermatozoa was significantly reduced in the presence of GT1b. These results and the experiments on the influence of iron-chelating agent ethylenediamine tetraacetic acid (EDTA) as well as ferrous ion concentration itself on lipid peroxidation support the hypothesis that the protective effect of ganglioside against MDA generation could be the result of its chelating activity. Furthermore, superoxide anion release of phorbol myristate acetate-stimulated spermatozoa was significantly reduced in the presence of 50 and 100 ,mol l,1 GD1b (P < 0.05) and GT1b (P < 0.005). The inhibitory effect of 100 ,mol l,1 GT1b on spermatozoa from infertile normozoospermic men was statistically significant (P < 0.001; n = 21) and did not depend on the initial superoxide anion production. In conclusion, the protective action of GD1b and GT1b could be related to both scavenging of free radicals and metal-chelating properties, which might have relevance in the protection against oxidation-induced processes in human spermatozoa. [source] Preliminary X-ray crystallographic study of the receptor-binding domain of the D/C mosaic neurotoxin from Clostridium botulinumACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2010Nipawan Nuemket Botulinum toxin (BoNT) from Clostridium botulinum OFD05, isolated from bovine botulism, is a D/C mosaic-type BoNT. BoNTs possess binding, translocation and catalytic domains. The BoNT/OFD05 binding domain exhibits significant sequence identity to BoNT/C, which requires a single ganglioside as a binding receptor on neuronal cells, while BoNT/A and BoNT/B require two receptors for specific binding. To determine the binding mechanism of BoNT/OFD05 and its ganglioside receptors on neuronal cells, recombinant BoNT/OFD05 receptor-binding domain has been expressed, purified and crystallized. Native and SeMet-derivative crystals showed X-ray diffraction to 2.8 and 3.1,Ĺ resolution, respectively. The crystals belonged to space group P212121. [source] Pancreatic fate of a 125I-labelled mouse monoclonal antibody directed against pancreatic B-cell surface ganglioside(s) in control and diabetic ratsCELL BIOCHEMISTRY AND FUNCTION, Issue 2 2001Laurence Ladri Abstract The possible use of a mouse monoclonal antibody directed against rat pancreatic B-cell surface ganglioside(s) and labelled with radioactive iodine for selective imaging of the endocrine pancreas by a non-invasive procedure was investigated by following its pancreatic fate in experiments conducted either in vitro by incubation of rat isolated pancreatic islets, acinar tissue and pancreatic pieces or in vivo after intravenous injection of the 125I-labelled antibodies ([125I],-G). Although the binding of [125I],-G per µg protein was about one order of magnitude higher in isolated islets than in acinar tissue, no significant difference was detected when comparing pancreatic pieces or isolated islets from control animals and rats rendered diabetic by one or two prior administrations of streptozotocin (STZ rats). Likewise, except in one set of experiments, no significant difference was found between control animals and STZ rats, when measuring the radioactive content of the pancreatic gland, relative to that of plasma, 1,4 days after the intravenous injection of [125I],-G. These findings indicate that under the present experimental conditions, the mouse monoclonal antibody labelled with radioactive iodine does not appear to be a promising tool for selective imaging of the endocrine pancreas, e.g. by single photon emission computerized tomography. Copyright © 2001 John Wiley & Sons, Ltd. [source] Fetal hydrops in GM1 gangliosidosis: A case reportACTA PAEDIATRICA, Issue 12 2005Maria Teresa Sinelli Abstract GM1 gangliosidosis is a rare disorder characterized by deficiency of the ,-galactosidase enzyme, with the resulting accumulation of glycolipids, oligosaccharides and especially GM1 ganglioside. It can be classified into three clinical types according to the time of onset: infantile, juvenile and adult form. We report a case of GM1 gangliosidosis presenting with fetal hydrops at 24 wk of gestation. The parents were consanguineous; the baby, born at 35 wk of gestation, was dysmorphic and presented severe generalized oedema. The most common cause of fetal hydrops was excluded. A lysosomal storage disease was suspected, and GM1 gangliosidosis was diagnosed. The child developed severe growth and mental retardation and died when she was 21 mo old. Conclusion: We suggest that the possible association between inborn errors of metabolism and antenatal ascites should be considered, in order to offer genetic counselling due to the high recurrence risk and the availability of early antenatal diagnosis. [source] Novel polysialogangliosides of skate brainFEBS JOURNAL, Issue 16 2000Structural determination of tetra, hexasialogangliosides with a NeuAc-GalNAc linkage, penta The gangliosides in the brain of a cartilaginous fish, skate (Bathyraja smirnovi), have been isolated and characterized by means of methylation analysis, antibody binding, enzymatic hydrolysis and MALDI-TOF MS. In addition to gangliosides with known structures (GM2, fucosyl-GM1, GD3, GD2, GT3 and GT2), five polysialogangliosides were isolated and characterized as having the following structures. (1) IV3NeuAc, III6NeuAc, II3NeuAc-Gg4Cer; (2) IV3NeuAc2, III6NeuAc, II3NeuAc-Gg4Cer; (3) IV3NeuAc, III6NeuAc, II3NeuAc2 -Gg4Cer; (4) IV3NeuAc, III6NeuAc, II3NeuAc3 -Gg4Cer; and (5) IV3NeuAc2, III6NeuAc, II3NeuAc3 -Gg4Cer. These structures are ,hybrid-type' which comprise combinations of ,-series and either a, b or c-series structures. Three gangliosides (2), (4) and (5), were novel. The main features of the ganglioside composition of skate brain were an abundance of gangliotriaosyl species, a lack of gangliotetraosyl species (except fucosyl-GM1), and an abundance of hybrid-types. These characteristics closely resemble those in shark brain which we reported previously [Nakamura, K., Tamai, Y. & Kasama, T. (1997) Neurochem. Int.30, 593,604]. Two of the hybrid-type gangliosides (1) and (4), were examined for their neuritogenic activity toward cultured neuronal cells (Neuro-2A), and were found to have more potent activity than nonhybrid-type gangliosides such as GM1. [source] Absence of oligodendroglial glucosylceramide synthesis does not result in CNS myelin abnormalities or alter the dysmyelinating phenotype of CGT-deficient miceGLIA, Issue 4 2010Laleh Saadat Abstract To examine the function of glycosphingolipids (GSLs) in oligodendrocytes, the myelinating cells of the central nervous system (CNS), mice were generated that lack oligodendroglial expression of UDP-glucose ceramide glucosyltransferase (encoded by Ugcg). These mice (Ugcgflox/flox;Cnp/Cre) did not show any apparent clinical phenotype, their total brain and myelin extracts had normal GSL content, including ganglioside composition, and myelin abnormalities were not detected in their CNS. These data indicate that the elimination of gangliosides from oligodendrocytes is not detrimental to myelination. These mice were also used to asses the potential compensatory effect of hydroxyl fatty acid glucosylceramide (HFA-GlcCer) accumulation in UDP-galactose:ceramide galactosyltransferase (encoded by Cgt, also known as Ugt8a) deficient mice. At postnatal day 18, the phenotypic characteristics of the Ugcgflox/flox;Cnp/Cre;Cgt,/, mutants, including the degree of hypomyelination, were surprisingly similar to that of Cgt,/, mice, suggesting that the accumulation of HFA-GlcCer in Cgt,/, mice does not modify their phenotype. These studies demonstrate that abundant, structurally intact myelin can form in the absence of glycolipids, which normally represent over 20% of the dry weight of myelin. © 2009 Wiley-Liss, Inc. [source] Anti-disialosyl antibodies mediate selective neuronal or Schwann cell injury at mouse neuromuscular junctionsGLIA, Issue 3 2005Susan K. Halstead Abstract The human paralytic neuropathy, Miller Fisher syndrome (MFS) is associated with autoantibodies specific for disialosyl epitopes on gangliosides GQ1b, GT1a, and GD3. Since these gangliosides are enriched in synaptic membranes, anti-ganglioside antibodies may target neuromuscular junctions (NMJs), thereby contributing to disease symptoms. We have shown previously that at murine NMJs, anti-disialosyl antibodies induce an ,-latrotoxin-like effect, electrophysiologically characterized by transient massive increase of spontaneous neurotransmitter release followed by block of evoked release, resulting in paralysis of the muscle preparation. Morphologically, motor nerve terminal damage, as well as perisynaptic Schwann cell (pSC) death is observed. The relative contributions of neuronal and pSC injury to the paralytic effect and subsequent repair are unknown. In this study, we have examined the ability of subsets of anti-disialosyl antibodies to discriminate between the neuronal and glial elements of the NMJ and thereby induce either neuronal injury or pSC death. Most antibodies reactive with GD3 induced pSC death, whereas antibody reactivity with GT1a correlated with the extent of nerve terminal injury. Motor nerve terminal injury resulted in massive uncontrolled exocytosis with paralysis. However, pSC ablation induced no acute (within 1 h) electrophysiological or morphological changes to the underlying nerve terminal. These data suggest that at mammalian NMJs, acute pSC injury or ablation has no major deleterious influence on synapse function. Our studies provide evidence for highly selective targeting of mammalian NMJ membranes, based on ganglioside composition, that can be exploited for examining axonal,glial interactions both in disease states and in normal NMJ homeostasis. © 2005 Wiley-Liss, Inc. [source] Gangliosides activate microglia via protein kinase C and NADPH oxidaseGLIA, Issue 3 2004Kyoung-Jin Min Abstract Microglia, the major immune effector cells in the central nervous system, are activated when the brain suffers injury. A number of studies indicate that gangliosides activate microglia. However, the signaling mechanisms involved in microglial activation are not yet to be elucidated. Our results show that gangliosides induce the expression of interleukin (IL)-1,, tumor necrosis factor-, (TNF-,), and inducible nitric oxide synthase (iNOS) in rat brain microglia and BV2 murine microglia via protein kinase C (PKC) and NADPH oxidase. Expression of IL-1,, TNF-,, and iNOS in ganglioside-treated cells was significantly reduced in the presence of inhibitors of PKC (GF109203X, Gö6976, Ro31-8220, and rottlerin) and NADPH oxidase (diphenyleneiodonium chloride [DPI]). In response to gangliosides, PKC-,, ,II, and , and NADPH oxidase p67phox translocated from the cytosol to the membrane. ROS generation was also activated within 5 min of ganglioside treatment. Ganglioside-induced ROS generation was blocked by PKC inhibitors. Furthermore, ganglioside-induced activation of NF-,B, an essential transcription factor that mediates the expression of IL-1,, TNF-,, and iNOS, was reduced in the presence of GF109203X and DPI. Our results collectively suggest that gangliosides activate microglia via PKC and NADPH oxidase, which regulate activation of NF-,B. © 2004 Wiley-Liss, Inc. [source] O -acetylation of GD3 prevents its apoptotic effect and promotes survival of lymphoblasts in childhood acute lymphoblastic leukaemiaJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2008Kankana Mukherjee Abstract We have previously demonstrated induction of O -acetylated sialoglycoproteins on lymphoblasts of childhood acute lymphoblastic leukaemia (ALL). These molecules promote survival of lymphoblasts by preventing apoptosis. Although O -acetylated sialoglycoproteins are over expressed, the status of O -acetylation of gangliosides and their role in lymphoblasts survival remains to be explored in ALL patients. Here, we have observed enhanced levels of 9- O -acetylated GD3 (9- O -AcGD3) in the lymphoblasts of patients and leukaemic cell line versus disialoganglioside GD3 in comparison to the normal cells. Localization of GD3 and 9- O -AcGD3 on mitochondria of patient's lymphoblasts has been demonstrated by immuno-electron microscopy. The exogenous administration of GD3-induced apoptosis in lymphoblasts as evident from the nuclear fragmentation and sub G0/G1 apoptotic peak. In contrast, 9- O -AcGD3 failed to induce such apoptosis. We further explored the mitochondria-dependent pathway triggered during GD3-induced apoptosis in lymphoblasts. GD3 caused a time-dependent depolarization of mitochondrial membrane potential, release of cytochrome c and 7.4- and 8-fold increased in caspase 9 and caspase 3 activity respectively. However, under identical conditions, an equimolar concentration of 9- O -AcGD3 failed to induce similar effects. Interestingly, 9- O -AcGD3 protected the lymphoblasts from GD3-induced apoptosis when administered in equimolar concentrations simultaneously. In situ de- O -acetylation of 9- O -AcGD3 with sodium salicylate restores the GD3-responsiveness to apoptotic signals. Although both GD3 and 9- O -acetyl GD3 localize to mitochondria, these two structurally related molecules may play different roles in ALL-disease biology. Taken together, our results suggest that O -acetylation of GD3, like that of O -acetylated sialoglycoproteins, might be a general strategy adopted by leukaemic blasts towards survival in ALL. J. Cell. Biochem. 105: 724,734, 2008. © 2008 Wiley-Liss, Inc. [source] A sialylation study of mouse brain gangliosides by MALDI a-TOF and o-TOF mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2008Mostafa Zarei Abstract Matrix-assisted laser desorption/ionization (MALDI) process of sialoglycoconjugates is generally accompanied by different levels of cleavage of sialic acid residues and/or by dehydration, and decarboxylation reactions. Quantitative densitometry of the mouse brain ganglioside (MBG) components separated by high-performance thin layer chromatography (HPTLC) and evidenced by orcinol staining was a basis to verify the ganglioside composition pattern with respect to the relative abundances of individual components in the mixture. A systematic mass spectrometry (MS) sialylation analysis has been carried out to evaluate the feasibility of an axial time-of-flight (a-TOF) MS, equipped with a vacuum MALDI source and an orthogonal-TOF (o-TOF) instrument with an ion source operated at about 1 mbar of N2. Besides, the esterification by one methyl group of the carboxyl group in sialic acid to increase the stability of the ganglioside species for MALDI MS analysis has been tested and the yield of intact ganglioside species and of the neutral loss of water and carbon dioxide estimated. For the sialylation analysis of native ganglioside mixtures the MALDI o-TOF analysis with 6-azo-2-thiothymine/diammonium citrate (ATT/DAC) as a matrix appears as an optimal approach for ganglioside profiling. Copyright © 2008 John Wiley & Sons, Ltd. [source] Accelerated release of exosome-associated GM1 ganglioside (GM1) by endocytic pathway abnormality: another putative pathway for GM1-induced amyloid fibril formationJOURNAL OF NEUROCHEMISTRY, Issue 1 2008Kohei Yuyama Abstract Exosomes are extracellularly released small vesicles that are derived from multivesicular bodies formed via the endocytic pathway. We treated pheochromocytoma PC12 cells with chloroquine, an acidotropic agent, which potently perturbs membrane trafficking from endosomes to lysosomes. Chloroquine treatment increased the level of GM1 ganglioside in cell media only when the cells were exposed to KCl for depolarization, which is known to enhance exosome release from neurons. In the sucrose-density-gradient fractionation of cell media, GM1 ganglioside was exclusively recovered with Alix, a specific marker of exosomes, in the fractions with the density corrresponding to that of exosomes. Notably, amyloid-, assembly was markedly accelerated when incubated with the exosome fraction prepared from the culture media of PC12 cells treated with chloroquine and KCl. Furthermore, amyloid-, assembly was significantly suppressed by the co-incubation with an antibody specific to GM1-bound amyloid-,, an endogenous seed for amyloid formation of Alzheimer's disease. Together with our previous finding that chloroquine treatment induces the accumulation of GM1 ganglioside in early endosomes, results of this study suggest that endocytic pathway abnormality accelerates the release of exosome-associated GM1 ganglioside following its accumulation in early endosomes. Furthermore, this study also suggests that extracellular amyloid fibril formation is induced by not only GM1 gangliosides accumulated on the surface of the cells but also those released in association with exosomes. [source] Effects of ethanol on gangliosides in the plasma, liver, and brain of inbred mouse strainsJOURNAL OF NEUROCHEMISTRY, Issue 2002M. I. Saito The mouse inbred strains C57BL/6ByJ and BALB/cJ show genetically different alcohol-related behaviors. Using these strains, we examined ganglioside contents in the plasma, liver, and brain with or without acute ethanol treatment. The quantification of GM1 was performed with a TLC-immunostaining procedure using choleragenoid, and the contents of other gangliosides were measured after staining with resorcinol reagents. It is known that there are polymorphisms in ganglioside compositions among inbred mouse strains. We found that the plasma GM1 level in BALB/cJ mice (1.6 ± 0.6 ng/,L) was 12 times higher than the level found in C57BL/6ByJ mice (0.13 ± 0.03 ng/,L) although the major ganglioside in both strains was GM2. The ganglioside profiles in the liver were similar to those of the plasma, and the GM1 level in BALB/cJ was 25 times higher than that of C57BL/6ByJ. The liver probably synthesizes the plasma gangliosides as suggested in other studies. The total brain ganglioside compositions were also different between BALB/cJ and C57BL/6ByJ. The levels of GD1b and GQ1b were higher in BALB/cJ although the GM1 contents were similar. These animals were injected with 20% ethanol intraperitoneally in a single dose of 3 g/kg and the ganglioside contents were measured after 4 h. The GM1 levels in the liver and plasma were lower in ethanol-treated animals while the GM1 levels were higher in erythrocytes and brains. Since it has been shown that the administration of GM1 attenuates or modifies the effects of ethanol in several animal models, the difference in GM1 contents in the plasma between BALB/cJ and C57BL/6ByJ may contribute to some of the differences in ethanol-related behaviors or toxicity between these strains. [source] Characterization of mouse marrow stromal cellsJOURNAL OF NEUROCHEMISTRY, Issue 2002S. S Liour Neural transplantation is a promising therapy for neurodegenerative diseases, including Parkinson's, Huntington's, Alzeheimer's, as well as mucopolysaccharidoses. However, neural transplantation is an invasive procedure in the early stages of research and development. In contrast, bone marrow transplantation has been used in medical treatment of immune and hematological disorders and genetic diseases. A increasing number of research reports suggest that cells derived from bone marrow, particularly mesenchymal stem cells, cannot only migrate into brains of recipient rodents after IV administration, but also differentiate into neurons and glia, to facilitate the functional recovery of rats after stroke or brain trauma. The lack of exclusive cell markers for mesenchymal stem cells makes them difficult to study. We isolated mouse marrow stromal cells and studied the expression of markers, particularly glycosphingolipids on their cell surface. Bone marrow was aspirated from femurs of two-month-old mice, and the stromal cells were propagated in attached cultures. Immuncytochemical analysis suggested that most stromal cells were immunopositive for antibodies against IGFR, flk-1, and CD44. Analysis of the glycosphingolipid composition by HPTLC revealed that GM3, GM2, GM1, and GD1a were the major gangliosides expressed in stromal cell in culture. Glucosylceramide, lactosylceramide, and paragloboside were the major neutral glycolipids expressed in these cells. Combinations of these cell surface markers may prove useful in the isolation and characterization of mesenchymal stem cells. Acknowledgements:, Supported by grants from NIH NS11853 and the Children's Medical Research Foundation. [source] Expression of gangliosides in an immortalized neural progenitor/stem cell lineJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2003Keiji Suetake Abstract Glycosphingolipids (GSLs) are known to play important roles in cellular growth and differentiation in the nervous system. The change in expression of gangliosides is correlated with crucial developmental events and is evolutionarily conserved among many vertebrate species. The emergence of neural progenitors represents a crucial step in neural development, but little is known about the exact composition and subcellular localization of gangliosides in neural progenitor cells. The C17.2 cell line was derived after v- myc transformation of neural progenitor cells isolated from neonatal mouse cerebellar cortex. The developmental potential of C17.2 cells is similar to that of endogenous neural progenitor/stem cells in that they are multipotential and capable of differentiating into all neural cell types. We characterized the GSL composition of C17.2 cells and found the presence of only a-series gangliosides. Subcellular localization studies revealed that GM1 and GD1a are localized mainly on the plasma membrane and partly in the cytoplasm, both as punctate clusters. Reverse transcription-polymerase chain reaction revealed the absence of ST-II transcripts in C17 cells, which most likely accounts for the lack of expression of b- and c-series complex gangliosides in this cell line. These data suggest that the divergence in ganglioside expression in C17.2 cells is regulated at the transcriptional level. © 2003 Wiley-Liss, Inc. [source] Effects of detergents on the secondary structures of prion protein peptides as studied by CD spectroscopyJOURNAL OF PEPTIDE SCIENCE, Issue 4 2003Dr Yoshihiro Kuroda Abstract Pathogenic prion proteins (PrPSc) are thought to be produced by ,-helical to ,-sheet conformational changes in the normal cellular prion proteins (PrPC) located solely in the caveolar compartments. In order to inquire into the possible conformational changes due to the influences of hydrophobic environments within caveolae, the secondary structures of prion protein peptides were studied in various kinds of detergents by CD spectra. The peptides studied were PrP(129,154) and PrP(192,213); the former is supposed to assume ,-sheets and the latter ,-helices, in PrPSc. The secondary structure analyses for the CD spectra revealed that in buffer solutions, both PrP(129,154) and PrP(192,213) mainly adopted random-coils (,60%), followed by ,-sheets (30%,40%). PrP(129,154) showed no changes in the secondary structures even in various kinds of detergents such as octyl-,- D -glucopyranoside (OG), octy-,- D -maltopyranoside (OM), sodium dodecyl sulfate (SDS), Zwittergent 3,14 (ZW) and dodecylphosphocholine (DPC). In contrast, PrP(192,213) changed its secondary structure depending on the concentration of the detergents. SDS, ZW, OG and OM increased the ,-helical content, and decreased the ,-sheet and random-coil contents. DPC also increased the ,-helical content, but to a lesser extent than did SDS, ZW, OG or OM. These results indicate that PrP(129,154) has a propensity to adopt predominantly ,-sheets. On the other hand, PrP(192,213) has a rather fickle propensity and varies its secondary structure depending on the environmental conditions. It is considered that the hydrophobic environments provided by these detergents may mimic those provided by gangliosides in caveolae, the head groups of which consist of oligosaccharide chains containing sialic acids. It is concluded that PrPC could be converted into a nascent PrPSc having a transient PrPSc like structure under the hydrophobic environments produced by gangliosides. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd. [source] Structure Of Campylobacter Jejuni Lipopolysaccharides Determines Antiganglioside Specificity And Clinical Features Of Guillain-Barre, And Miller Fisher PatientsJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2002CW Ang Ganglioside mimicry in the lipopolysaccharide (LPS) fraction of Campylobacter jejuni isolated from Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) patients was compared with isolates from patients with an uncomplicated enteritis. The antibody response to C. jejuni LPS and gangliosides in neuropathy patients and controls was compared as well. LPS from GBS and MFS-associated isolates more frequently contained ganglioside-like epitopes compared to control isolates. Almost all neuropathy patients showed a strong antibody response against LPS and multiple gangliosides in contrast to enteritis patients. Isolates from GBS patients more frequently had a GM1-like epitope than isolates from MFS patients. GQ1b-like epitopes were present in all MFS-associated isolates and was associated with anti-GQ1b antibody reactivity and the presence of oculomotor symptoms. These results demonstrate that the expression of ganglioside mimics is a risk factor for the development of post-Campylobacter neuropathy. This study provides additional evidence for the hypothesis that the LPS fraction determines the antiganglioside specificity and clinical features in post-Campylobacter neuropathy patients. [source] Murine fetal small-intestine grafts: Morphometric and immunohistochemical evaluationMICROSURGERY, Issue 1 2006Carlos Eduardo Saldanha De Almeida We investigated histopathological changes following murine fetal intestinal transplantation. Fetal intestine, obtained from a pregnant C57BL/6 mouse, was transplanted into BALB/c and C57Bl/6 mice. Recipients were divided into three groups: isogeneic, and allogeneic treated with 3 mg/kg/day gangliosides (Allo-a) or 9 mg/kg/day (Allo-b). One week after transplant, all grafts showed good viability, confirmed by cellular mitosis in the mucosa and a well-defined propria muscular layer. Isogeneic grafts showed a thicker muscular layer than in the Allo-a (P = 0.02) and Allo-b (P = 0.004) groups. There was no difference in number of mitotic cells among groups. Goblet cells were significantly reduced in allografts treated with 3 mg gangliosides (P = 0.013) or 9 mg gangliosides (P = 0.002) compared to isografts. Villi height was similar in all studied groups. There was no difference in positivity of the enteric nervous system among groups. Atrophy was more common in the allogeneic groups, suggesting that isografts had better development than allografts treated with gangliosides. © 2006 Wiley-Liss, Inc. Microsurgery 26: 61,64, 2006. [source] Can antiglycolipid antibodies present in HIV-infected individuals induce immune demyelination?NEUROPATHOLOGY, Issue 4 2000Steven Petratos Of the eight clinically defined neuropathies associated with HIV infection, there is compelling evidence that acute and chronic inflammatory demyelinating polyneuropathy (IDPN) have an autoimmune pathogenesis. Many non-HIV infected individuals who suffer from sensorymotor nerve dysfunction have autoimmune indicators. The immunopathogenesis of demyelination must involve neuritogenic components in myelin. The various antigens suspected to play a role in HIV-seronegative IDPN include (i) P2 protein; (ii) sulfatide (GalS); (iii) various gangliosides (especially GM1); (iv) galactocerebroside (GalC); and (v) glycoproteins or glycolipids with the carbohydrate epitope glucuronyl-3-sulfate. These glycoproteins or glycolipids may be individually targeted, or an immune attack may be raised against a combination of any of these epitopes. The glycolipids, however, especially GalS, have recently evoked much interest as mediators of immune events underlying both non-HIV and HIV-associated demyelinating neuropathies. The present review outlines the recent research findings of antiglycolipid antibodies present in HIV-infected patients with and without peripheral nerve dysfunction, in an attempt to arrive at some consensus as to whether these antibodies may play a role in the immunopathogenesis of HIV-associated inflammatory demyelinating polyneuropathy. [source] | ||||||||||||||||