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Sample records for 9-o-acetyl gd3 gangliosides

  1. GD3/proteosome vaccines induce consistent IgM antibodies against the ganglioside GD3.

    PubMed

    Livingston, P O; Calves, M J; Helling, F; Zollinger, W D; Blake, M S; Lowell, G H

    1993-09-01

    The gangliosides of melanoma and other tumours of neuroectodermal origin are suitable targets for immune intervention with tumour vaccines. The optimal vaccines in current use contain ganglioside plus bacillus Calmette-Guérin and induce considerable morbidity. We have screened a variety of new adjuvants in the mouse, and describe one antigen-delivery system, proteosomes, which is especially effective. Highly hydrophobic Neisserial outer membrane proteins (OMP) form multimolecular liposome-like vesicular structures termed proteosomes which can readily incorporate amphiphilic molecules such as GD3 ganglioside. The optimal GD3/proteosome vaccine formulation for induction of GD3 antibodies in the mouse is determined. Interestingly, the use of potent immunological adjuvants in addition to proteosomes augments the IgM and IgG antibody titres against OMP in these vaccines but GD3 antibody titres are unaffected. The application of proteosomes to enhance the immune response to GD3 extends the concept of the proteosome immunopotentiating system from lipopeptides to amphipathic carbohydrate epitopes such as cell-surface gangliosides. The demonstrated safety of meningococcal OMP in humans and the data in mice presented here suggest that proteosome vaccines have potential for augmenting the immunogenicity of amphipathic tumour antigens in humans.

  2. Expression of GD2 and GD3 gangliosides in human embryonic neural stem cells

    PubMed Central

    Yanagisawa, Makoto; Yoshimura, Saori; Yu, Robert K

    2011-01-01

    NSCs (neural stem cells) are undifferentiated neural cells endowed with a high potential for proliferation and a capacity for self-renewal with retention of multipotency to differentiate into neurons and glial cells. It has been recently reported that GD3, a b-series ganglioside, is a marker molecule for identifying and isolating mouse NSCs. However, the expression of gangliosides in human NSCs is largely unknown. In the present study, we analysed the expression of gangliosides, GD2 and GD3, in human NSCs that were isolated from human brains at gestational week 17 in the form of neurospheres, which are floating clonal aggregates formed by NSCs in vitro. Employing immunocytochemistry, we found that human NSCs were strongly reactive to anti-GD2 antibody and relatively weakly reactive to anti-GD3 antibody. Treatment of these cells with an organic solvent such as 100% methanol, which selectively removes glycolipids from plasma membrane, abolished the immunoreactivity with those antibodies, indicating that the reactivity was due to GD2 and GD3, but not to GD2-/GD3-like glycoproteins or proteoglycans. The immunoreactivity of human NSCs to antibody against SSEA-1 (stage-specific embryonic antigen-1), a well-known carbohydrate antigen of NSCs, was not decreased by the treatment with 100% methanol, indicating that SSEA-1 is mainly carried by glycoproteins and/or proteoglycans in human NSCs. Our study suggests that GD2 and GD3 can be marker gangliosides for identifying human NSCs. PMID:21395555

  3. Induction of IgG antibodies against GD3 ganglioside in rabbits by an anti-idiotypic monoclonal antibody.

    PubMed Central

    Chapman, P B; Houghton, A N

    1991-01-01

    Anti-idiotypic MAb were raised in syngeneic mice against a mouse MAb recognizing GD3 ganglioside (MAb R24). Two anti-idiotypic MAb, designated BEC2 and BEC3, recognized distinct determinants on MAb R24 that mapped near or within the GD3-binding site. New Zealand white rabbits, which express GD3 on normal tissues, were immunized with either BEC2, BEC3, or control MAb FLOPC-21. All rabbits developed high and equivalent titers of antibodies against mouse immunoglobulins. Immunization with BEC2 and BEC3 induced rabbit antibodies expressing R24 idiotype as demonstrated by their ability to inhibit BEC2 binding to R24. Antibodies (IgG and IgM) reacting with GD3 developed in five of eight rabbits immunized with BEC2 but not in rabbits immunized with BEC3 or with control MAb. Serum antibodies against GD3 did not cross-react with other gangliosides. These results show that MAb BEC2 can mimic GD3 ganglioside and can induce antibodies against GD3 ganglioside despite expression of GD3 on normal rabbit tissue. Images PMID:2056117

  4. Mice Lacking GD3 Synthase Display Morphological Abnormalities in the Sciatic Nerve and Neuronal Disturbances during Peripheral Nerve Regeneration

    PubMed Central

    Ribeiro-Resende, Victor Túlio; Gomes, Tiago Araújo; de Lima, Silmara; Nascimento-Lima, Maiara; Bargas-Rega, Michele; Santiago, Marcelo Felipe; Reis, Ricardo Augusto de Melo; de Mello, Fernando Garcia

    2014-01-01

    The ganglioside 9-O-acetyl GD3 is overexpressed in peripheral nerves after lesioning, and its expression is correlated with axonal degeneration and regeneration in adult rodents. However, the biological roles of this ganglioside during the regenerative process are unclear. We used mice lacking GD3 synthase (Siat3a KO), an enzyme that converts GM3 to GD3, which can be further converted to 9-O-acetyl GD3. Morphological analyses of longitudinal and transverse sections of the sciatic nerve revealed significant differences in the transverse area and nerve thickness. The number of axons and the levels of myelin basic protein were significantly reduced in adult KO mice compared to wild-type (WT) mice. The G-ratio was increased in KO mice compared to WT mice based on quantification of thin transverse sections stained with toluidine blue. We found that neurite outgrowth was significantly reduced in the absence of GD3. However, addition of exogenous GD3 led to neurite growth after 3 days, similar to that in WT mice. To evaluate fiber regeneration after nerve lesioning, we compared the regenerated distance from the lesion site and found that this distance was one-fourth the length in KO mice compared to WT mice. KO mice in which GD3 was administered showed markedly improved regeneration compared to the control KO mice. In summary, we suggest that 9-O-acetyl GD3 plays biological roles in neuron-glia interactions, facilitating axonal growth and myelination induced by Schwann cells. Moreover, exogenous GD3 can be converted to 9-O-acetyl GD3 in mice lacking GD3 synthase, improving regeneration. PMID:25330147

  5. Targeted Delivery of Immunotoxin by Antibody to Ganglioside GD3: A Novel Drug Delivery Route for Tumor Cells

    PubMed Central

    Torres Demichelis, Vanina; Vilcaes, Aldo A.; Iglesias-Bartolomé, Ramiro; Ruggiero, Fernando M.; Daniotti, Jose L.

    2013-01-01

    Gangliosides are sialic acid-containing glycolipids expressed on plasma membranes from nearly all vertebrate cells. The expression of ganglioside GD3, which plays essential roles in normal brain development, decreases in adults but is up regulated in neuroectodermal and epithelial derived cancers. R24 antibody, directed against ganglioside GD3, is a validated tumor target which is specifically endocytosed and accumulated in endosomes. Here, we exploit the internalization feature of the R24 antibody for the selective delivery of saporin, a ribosome-inactivating protein, to GD3-expressing cells [human (SK-Mel-28) and mouse (B16) melanoma cells and Chinese hamster ovary (CHO)-K1 cells]. This immunotoxin showed a specific cytotoxicity on tumor cells grew on 2D monolayers, which was further evident by the lack of any effect on GD3-negative cells. To estimate the potential antitumor activity of R24-saporin complex, we also evaluated the effect of the immunotoxin on the clonogenic growth of SK-Mel-28 and CHO-K1GD3+ cells cultured in attachment-free conditions. A drastic growth inhibition (>80–90%) of the cell colonies was reached after 3 days of immunotoxin treatment. By the contrary, colonies continue to growth at the same concentration of the immuntoxin, but in the absence of R24 antibody, or in the absence of both immunotoxin and R24, undoubtedly indicating the specificity of the effect observed. Thus, the ganglioside GD3 emerge as a novel and attractive class of cell surface molecule for targeted delivery of cytotoxic agents and, therefore, provides a rationale for future therapeutic intervention in cancer. PMID:23383146

  6. Monoclonal antibody R24 distinguishes between different N-acetyl- and N-glycolylneuraminic acid derivatives of ganglioside GD3.

    PubMed

    Tai, T; Kawashima, I; Furukawa, K; Lloyd, K O

    1988-01-01

    Monoclonal antibody (MAb) R24 was previously shown to be directed toward ganglioside GD3 [Pukel, C. S., Lloyd, K. O., Travassos, L. R., Dippold, W. G., Oettgen, H. F., and Old, L. J. (1982) J. Exp. Med. 155, 1133-1147]. The structural specificity of the MAb has now been further characterized based on binding to structurally related glycolipids, including four GD3 derivatives with different N-acetylneuraminic acid (NeuAc) and N-glycolylneuraminic acid (NeuGc) substituents. Three assay systems (enzyme immunostaining on thin-layer chromatography, enzyme-linked immunosorbent assay, and immune adherence inhibition assay) were used. MAb R24 was found to react with (NeuAc-NeuAc-)GD3 and (NeuAc-NeuGc-)GD3 but not with (NeuGc-NeuAc-)GD3 or (NeuGc-NeuGc-)GD3. These results clearly indicate that the outer sialic acid (Sia) moiety of GD3 is crucial and must be a NeuAc residue, while the inner sialic acid is less involved in binding to the MAb and can be either NeuAc or NeuGc. The MAb was also found to cross-react weakly with two gangliosides, GT1a and GQ1b, but none of other gangliosides nor neutral glycolipids tested reacted. These findings suggest that the epitope detected by MAb R24 is the trisaccharide structure NeuAc alpha 2----8Sia alpha 2----3Gal-, which must be in a terminal position.

  7. UVB-irradiated keratinocytes induce melanoma-associated ganglioside GD3 synthase gene in melanocytes via secretion of tumor necrosis factor α and interleukin 6.

    PubMed

    Miyata, Maiko; Ichihara, Masatoshi; Tajima, Orie; Sobue, Sayaka; Kambe, Mariko; Sugiura, Kazumitsu; Furukawa, Koichi; Furukawa, Keiko

    2014-03-01

    Although expression of gangliosides and their synthetic enzyme genes in malignant melanomas has been well studied, that in normal melanocytes has been scarcely analyzed. In particular, changes in expression levels of glycosyltransferase genes responsible for ganglioside synthesis during evolution of melanomas from melanocytes are very important to understand roles of gangliosides in melanomas. Here, expression of glycosyltransferase genes related to the ganglioside synthesis was analyzed using RNAs from cultured melanocytes and melanoma cell lines. Quantitative RT-PCR revealed that melanomas expressed high levels of mRNA of GD3 synthase and GM2/GD2 synthase genes and low levels of GM1/GD1b synthase genes compared with melanocytes. As a representative exogenous stimulation, effects of ultraviolet B (UVB) on the expression levels of 3 major ganglioside synthase genes in melanocytes were analyzed. Although direct UVB irradiation of melanocytes caused no marked changes, culture supernatants of UVB-irradiated keratinocytes (HaCaT cells) induced definite up-regulation of GD3 synthase and GM2/GD2 synthase genes. Detailed examination of the supernatants revealed that inflammatory cytokines such as TNFα and IL-6 enhanced GD3 synthase gene expression. These results suggest that inflammatory cytokines secreted from UVB-irradiated keratinocytes induced melanoma-associated ganglioside synthase genes, proposing roles of skin microenvironment in the promotion of melanoma-like ganglioside profiles in melanocytes. PMID:24548412

  8. UVB-irradiated keratinocytes induce melanoma-associated ganglioside GD3 synthase gene in melanocytes via secretion of tumor necrosis factor α and interleukin 6.

    PubMed

    Miyata, Maiko; Ichihara, Masatoshi; Tajima, Orie; Sobue, Sayaka; Kambe, Mariko; Sugiura, Kazumitsu; Furukawa, Koichi; Furukawa, Keiko

    2014-03-01

    Although expression of gangliosides and their synthetic enzyme genes in malignant melanomas has been well studied, that in normal melanocytes has been scarcely analyzed. In particular, changes in expression levels of glycosyltransferase genes responsible for ganglioside synthesis during evolution of melanomas from melanocytes are very important to understand roles of gangliosides in melanomas. Here, expression of glycosyltransferase genes related to the ganglioside synthesis was analyzed using RNAs from cultured melanocytes and melanoma cell lines. Quantitative RT-PCR revealed that melanomas expressed high levels of mRNA of GD3 synthase and GM2/GD2 synthase genes and low levels of GM1/GD1b synthase genes compared with melanocytes. As a representative exogenous stimulation, effects of ultraviolet B (UVB) on the expression levels of 3 major ganglioside synthase genes in melanocytes were analyzed. Although direct UVB irradiation of melanocytes caused no marked changes, culture supernatants of UVB-irradiated keratinocytes (HaCaT cells) induced definite up-regulation of GD3 synthase and GM2/GD2 synthase genes. Detailed examination of the supernatants revealed that inflammatory cytokines such as TNFα and IL-6 enhanced GD3 synthase gene expression. These results suggest that inflammatory cytokines secreted from UVB-irradiated keratinocytes induced melanoma-associated ganglioside synthase genes, proposing roles of skin microenvironment in the promotion of melanoma-like ganglioside profiles in melanocytes.

  9. Ganglioside GD3 Enhances Invasiveness of Gliomas by Forming a Complex with Platelet-derived Growth Factor Receptor α and Yes Kinase*

    PubMed Central

    Ohkawa, Yuki; Momota, Hiroyuki; Kato, Akira; Hashimoto, Noboru; Tsuda, Yusuke; Kotani, Norihiro; Honke, Koichi; Suzumura, Akio; Furukawa, Keiko; Ohmi, Yuhsuke; Natsume, Atsushi; Wakabayashi, Toshihiko; Furukawa, Koichi

    2015-01-01

    There have been a few studies on the ganglioside expression in human glioma tissues. However, the role of these gangliosides such as GD3 and GD2 has not been well understood. In this study we employed a genetically engineered mouse model of glioma to clarify the functions of GD3 in gliomas. Forced expression of platelet-derived growth factor B in cultured astrocytes derived from p53-deficient mice resulted in the expression of GD3 and GD2. GD3-positive astrocytes exhibited increased cell growth and invasion activities along with elevated phosphorylation of Akt and Yes kinase. By enzyme-mediated activation of radical sources reaction and mass spectrometry, we identified PDGF receptor α (PDGFRα) as a GD3-associated molecule. GD3-positive astrocytes showed a significant amount of PDGFRα in glycolipid-enriched microdomains/rafts compared with GD3-negative cells. Src kinase family Yes was co-precipitated with PDGFRα, and its pivotal role in the increased cell invasion of GD3-positive astrocytes was demonstrated by silencing with anti-Yes siRNA. Direct association between PDGFRα and GD3 was also shown, suggesting that GD3 forms ternary complex with PDGFRα and Yes. The fact that GD3, PDGFRα, and activated Yes were colocalized in lamellipodia and the edge of tumors in cultured cells and glioma tissues, respectively, suggests that GD3 induced by platelet-derived growth factor B enhances PDGF signals in glycolipid-enriched microdomain/rafts, leading to the promotion of malignant phenotypes such as cell proliferation and invasion in gliomas. PMID:25940087

  10. Ganglioside GD3 Enhances Invasiveness of Gliomas by Forming a Complex with Platelet-derived Growth Factor Receptor α and Yes Kinase.

    PubMed

    Ohkawa, Yuki; Momota, Hiroyuki; Kato, Akira; Hashimoto, Noboru; Tsuda, Yusuke; Kotani, Norihiro; Honke, Koichi; Suzumura, Akio; Furukawa, Keiko; Ohmi, Yuhsuke; Natsume, Atsushi; Wakabayashi, Toshihiko; Furukawa, Koichi

    2015-06-26

    There have been a few studies on the ganglioside expression in human glioma tissues. However, the role of these gangliosides such as GD3 and GD2 has not been well understood. In this study we employed a genetically engineered mouse model of glioma to clarify the functions of GD3 in gliomas. Forced expression of platelet-derived growth factor B in cultured astrocytes derived from p53-deficient mice resulted in the expression of GD3 and GD2. GD3-positive astrocytes exhibited increased cell growth and invasion activities along with elevated phosphorylation of Akt and Yes kinase. By enzyme-mediated activation of radical sources reaction and mass spectrometry, we identified PDGF receptor α (PDGFRα) as a GD3-associated molecule. GD3-positive astrocytes showed a significant amount of PDGFRα in glycolipid-enriched microdomains/rafts compared with GD3-negative cells. Src kinase family Yes was co-precipitated with PDGFRα, and its pivotal role in the increased cell invasion of GD3-positive astrocytes was demonstrated by silencing with anti-Yes siRNA. Direct association between PDGFRα and GD3 was also shown, suggesting that GD3 forms ternary complex with PDGFRα and Yes. The fact that GD3, PDGFRα, and activated Yes were colocalized in lamellipodia and the edge of tumors in cultured cells and glioma tissues, respectively, suggests that GD3 induced by platelet-derived growth factor B enhances PDGF signals in glycolipid-enriched microdomain/rafts, leading to the promotion of malignant phenotypes such as cell proliferation and invasion in gliomas.

  11. UVB-irradiated keratinocytes induce melanoma-associated ganglioside GD3 synthase gene in melanocytes via secretion of tumor necrosis factor α and interleukin 6

    SciTech Connect

    Miyata, Maiko; Ichihara, Masatoshi; Tajima, Orie; Sobue, Sayaka; Kambe, Mariko; Sugiura, Kazumitsu; Furukawa, Koichi; Furukawa, Keiko

    2014-03-07

    Highlights: • Melanocytes showed low ST8SIA1 and high B3GALT4 levels in contrast with melanomas. • Direct UVB irradiation of melanocytes did not induce ganglioside synthase genes. • Culture supernatants of UVB-irradiated keratinocytes induced ST8SIA1 in melanocytes. • TNFα and IL-6 secreted from keratinocytes enhanced ST8SIA1 expression in melanocytes. • Inflammatory cytokines induced melanoma-related ST8SIA1 in melanocytes. - Abstract: Although expression of gangliosides and their synthetic enzyme genes in malignant melanomas has been well studied, that in normal melanocytes has been scarcely analyzed. In particular, changes in expression levels of glycosyltransferase genes responsible for ganglioside synthesis during evolution of melanomas from melanocytes are very important to understand roles of gangliosides in melanomas. Here, expression of glycosyltransferase genes related to the ganglioside synthesis was analyzed using RNAs from cultured melanocytes and melanoma cell lines. Quantitative RT-PCR revealed that melanomas expressed high levels of mRNA of GD3 synthase and GM2/GD2 synthase genes and low levels of GM1/GD1b synthase genes compared with melanocytes. As a representative exogenous stimulation, effects of ultraviolet B (UVB) on the expression levels of 3 major ganglioside synthase genes in melanocytes were analyzed. Although direct UVB irradiation of melanocytes caused no marked changes, culture supernatants of UVB-irradiated keratinocytes (HaCaT cells) induced definite up-regulation of GD3 synthase and GM2/GD2 synthase genes. Detailed examination of the supernatants revealed that inflammatory cytokines such as TNFα and IL-6 enhanced GD3 synthase gene expression. These results suggest that inflammatory cytokines secreted from UVB-irradiated keratinocytes induced melanoma-associated ganglioside synthase genes, proposing roles of skin microenvironment in the promotion of melanoma-like ganglioside profiles in melanocytes.

  12. 9-O-Acetylation of sialic acids is catalysed by CASD1 via a covalent acetyl-enzyme intermediate.

    PubMed

    Baumann, Anna-Maria T; Bakkers, Mark J G; Buettner, Falk F R; Hartmann, Maike; Grove, Melanie; Langereis, Martijn A; de Groot, Raoul J; Mühlenhoff, Martina

    2015-01-01

    Sialic acids, terminal sugars of glycoproteins and glycolipids, play important roles in development, cellular recognition processes and host-pathogen interactions. A common modification of sialic acids is 9-O-acetylation, which has been implicated in sialoglycan recognition, ganglioside biology, and the survival and drug resistance of acute lymphoblastic leukaemia cells. Despite many functional implications, the molecular basis of 9-O-acetylation has remained elusive thus far. Following cellular approaches, including selective gene knockout by CRISPR/Cas genome editing, we here show that CASD1--a previously identified human candidate gene--is essential for sialic acid 9-O-acetylation. In vitro assays with the purified N-terminal luminal domain of CASD1 demonstrate transfer of acetyl groups from acetyl-coenzyme A to CMP-activated sialic acid and formation of a covalent acetyl-enzyme intermediate. Our study provides direct evidence that CASD1 is a sialate O-acetyltransferase and serves as key enzyme in the biosynthesis of 9-O-acetylated sialoglycans. PMID:26169044

  13. High resolution proton NMR studies of gangliosides. Structure of two types of GD3 lactones and their reactivity with monoclonal antibody R24.

    PubMed

    Ando, S; Yu, R K; Scarsdale, J N; Kusunoki, S; Prestegard, J H

    1989-02-25

    Ganglioside GD3 was converted at room temperature to two stable lactones, denoted as GD3 lactones I and II. The reaction sequence was presumed to be GD3----GD3 lactone I----GD3 lactone II based on the time course of their production. Lactone I behaved as a monosialoganglioside and lactone II as a neutral species. The two lactones were isolated by DEAE-Sephadex column chromatography. The positions of the inner ester linkages were investigated by two-dimensional J-correlated proton NMR spectroscopy. An ester linkage was most likely formed between the carboxyl group of the external sialic acid residue and C9-OH of the internal sialic acid residue in lactone I. In addition to this ester linkage, a second ester linkage between the carboxyl group of the internal sialic acid and C2-OH of the galactose residue was likely formed in lactone II. The structural changes induced by lactonization were further examined by their reactivity with the monoclonal antibody R24 (Puckel, C. S., Lloyd, K. O., Travassos, L. R., Dippold, W. G., Oettgen, H. F., and Old, L. J. (1982) J. Exp. Med. 155, 1133-1147), which reacted with GD3. R24 was found to bind weakly to GD3 lactone I, but not to GD3 lactone II. The results suggest that the monoclonal antibody requires both sialic acid residues for high affinity binding, and the complete lactonization results in a loss of negative charges and/or a change in the overall conformation of the oligosaccharide moiety which may account for the loss of binding.

  14. A therapeutic trial of human melanomas with combined small interfering RNAs targeting adaptor molecules p130Cas and paxillin activated under expression of ganglioside GD3.

    PubMed

    Makino, Yusuke; Hamamura, Kazunori; Takei, Yoshifumi; Bhuiyan, Robiul Hasan; Ohkawa, Yuki; Ohmi, Yuhsuke; Nakashima, Hideyuki; Furukawa, Keiko; Furukawa, Koichi

    2016-08-01

    We previously demonstrated that focal adhesion kinase (FAK), p130Cas and paxillin are crucially involved in the enhanced malignant properties under expression of ganglioside GD3 in melanoma cells. Therefore, molecules existing in the GD3-mediated signaling pathway could be considered as suitable targets for therapeutic intervention in malignant melanoma. The aim of this study was to determine whether blockade of p130Cas and/or paxillin by RNAi suppresses melanoma growth. We found a suitable dose (40 μM siRNA, 25 μl/tumor) of the siRNA to suppress p130Cas in the xenografts generated in nu/nu mice. Based on these results, we performed intratumoral (i.t.) treatment with anti-p130Cas and/or anti-paxillin siRNAs mixed with atelocollagen as a drug delivery system in a xenograft tumor of a human melanoma cell line, SK-MEL-28. Mixture of atelocollagen (1.75%) and an siRNA (500 or 1000 pmol/tumor) was injected into the tumors every 3 days after the first injection. An siRNA against human p130Cas markedly suppressed tumor growth of the xenograft in a dose-dependent manner, whereas siRNA against human paxillin slightly inhibited the tumor growth. A control siRNA against firefly luciferase showed no effect. To our surprise, siRNA against human p130Cas (500 or 1000 pmol/tumor) combined with siRNA against human paxillin dramatically suppressed tumor growth. In agreement with the tumor suppression effects of the anti-p130Cas siRNA, reduction in Ki-67 positive cell number as well as in p130Cas expression was demonstrated by immunohistostaining. These results suggested that blockade of GD3-mediated growth signaling pathways by siRNAs might be a novel and promising therapeutic strategy against malignant melanomas, provided signaling molecules such as p130Cas and paxillin are significantly expressed in individual cases. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc. PMID:27068854

  15. A therapeutic trial of human melanomas with combined small interfering RNAs targeting adaptor molecules p130Cas and paxillin activated under expression of ganglioside GD3.

    PubMed

    Makino, Yusuke; Hamamura, Kazunori; Takei, Yoshifumi; Bhuiyan, Robiul Hasan; Ohkawa, Yuki; Ohmi, Yuhsuke; Nakashima, Hideyuki; Furukawa, Keiko; Furukawa, Koichi

    2016-08-01

    We previously demonstrated that focal adhesion kinase (FAK), p130Cas and paxillin are crucially involved in the enhanced malignant properties under expression of ganglioside GD3 in melanoma cells. Therefore, molecules existing in the GD3-mediated signaling pathway could be considered as suitable targets for therapeutic intervention in malignant melanoma. The aim of this study was to determine whether blockade of p130Cas and/or paxillin by RNAi suppresses melanoma growth. We found a suitable dose (40 μM siRNA, 25 μl/tumor) of the siRNA to suppress p130Cas in the xenografts generated in nu/nu mice. Based on these results, we performed intratumoral (i.t.) treatment with anti-p130Cas and/or anti-paxillin siRNAs mixed with atelocollagen as a drug delivery system in a xenograft tumor of a human melanoma cell line, SK-MEL-28. Mixture of atelocollagen (1.75%) and an siRNA (500 or 1000 pmol/tumor) was injected into the tumors every 3 days after the first injection. An siRNA against human p130Cas markedly suppressed tumor growth of the xenograft in a dose-dependent manner, whereas siRNA against human paxillin slightly inhibited the tumor growth. A control siRNA against firefly luciferase showed no effect. To our surprise, siRNA against human p130Cas (500 or 1000 pmol/tumor) combined with siRNA against human paxillin dramatically suppressed tumor growth. In agreement with the tumor suppression effects of the anti-p130Cas siRNA, reduction in Ki-67 positive cell number as well as in p130Cas expression was demonstrated by immunohistostaining. These results suggested that blockade of GD3-mediated growth signaling pathways by siRNAs might be a novel and promising therapeutic strategy against malignant melanomas, provided signaling molecules such as p130Cas and paxillin are significantly expressed in individual cases. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.

  16. Functional activation of Src family kinase yes protein is essential for the enhanced malignant properties of human melanoma cells expressing ganglioside GD3.

    PubMed

    Hamamura, Kazunori; Tsuji, Momoko; Hotta, Hiroshi; Ohkawa, Yuki; Takahashi, Masataka; Shibuya, Hidenobu; Nakashima, Hideyuki; Yamauchi, Yoshio; Hashimoto, Noboru; Hattori, Hisashi; Ueda, Minoru; Furukawa, Keiko; Furukawa, Koichi

    2011-05-27

    The possible roles of Src family kinases in the enhanced malignant properties of melanomas related to GD3 expression were analyzed. Among Src family kinases only Yes, not Fyn or Src, was functionally involved in the increased cell proliferation and invasion of GD3-expressing transfectant cells (GD3+). Yes was located upstream of p130Cas and paxillin and at an equivalent level to focal adhesion kinase. Yes underwent autophosphorylation even before serum treatment and showed stronger kinase activity in GD3+ cells than in GD3- cells following serum treatment. Coimmunoprecipitation experiments revealed that Yes bound to focal adhesion kinase or p130Cas more strongly in GD3+ cells than in GD3- cells. As a possible mechanism for the enhancing effects of GD3 on cellular phenotypes, it was shown that majority of Yes was localized in glycolipid-enriched microdomain/rafts in GD3+ cells even before serum treatment, whereas it was scarcely detected in glycolipid-enriched microdomain/rafts in GD3- cells. An in vitro kinase assay of Yes revealed that coexistence of GD3 with Yes in membranous environments enhances the kinase activity of GD3- cell-derived Yes toward enolase, p125, and Yes itself. Knockdown of GD3 synthase resulted in the alleviation of tumor phenotypes and reduced activation levels of Yes. Taken together, these results suggest a role of GD3 in the regulation of Src family kinases.

  17. Milk-derived GM(3) and GD(3) differentially inhibit dendritic cell maturation and effector functionalities.

    PubMed

    Brønnum, H; Seested, T; Hellgren, L I; Brix, S; Frøkiaer, H

    2005-06-01

    Gangliosides are complex glycosphingolipids, which exert immune-modulating effects on various cell types. Ganglioside GD(3) and GM(3) are the predominant gangliosides of human breast milk but during the early phase of lactation, the content of GD(3) decreases while GM(3) increases. The biological value of gangliosides in breast milk has yet to be elucidated but when milk is ingested, dietary gangliosides might conceptually affect immune cells, such as dendritic cells (DCs). In this study, we address the in vitro effect of GD(3) and GM(3) on DC effector functionalities. Treatment of bone marrow-derived DCs with GD(3) before lipopolysaccharide-induced maturation decreased the production of interleukin-6 (IL-6), IL-10, IL-12 and tumor necrosis factor-alpha as well as reduced the alloreactivity in mixed leucocyte reaction (MLR). In contrast, only IL-10 and IL-12 productions were significantly inhibited by GM(3,) and the potency of DCs to activate CD4(+) cells in MLR was unaffected by GM(3). However, both gangliosides suppressed expression of CD40, CD80, CD86 and major histocompatibility complex class II on DCs. Because GD(3) overall inhibits DC functionalities more than GM(3), the immune modulating effect of the ganglioside fraction of breast milk might be more prominent in the commencement of lactation during which the milk contains the most GD(3). PMID:15963050

  18. The S protein of bovine coronavirus is a hemagglutinin recognizing 9-O-acetylated sialic acid as a receptor determinant.

    PubMed

    Schultze, B; Gross, H J; Brossmer, R; Herrler, G

    1991-11-01

    The S protein of bovine coronavirus (BCV) has been isolated from the viral membrane and purified by gradient centrifugation. Purified S protein was identified as a viral hemagglutinin. Inactivation of the cellular receptors by sialate 9-O-acetylesterase and generation of receptors by sialylation of erythrocytes with N-acetyl-9-O-acetylneuraminic acid (Neu5,9Ac2) indicate that S protein recognizes 9-O-acetylated sialic acid as a receptor determinant as has been shown previously for intact virions. The second glycoprotein of BCV, HE, which has been thought previously to be responsible for the hemagglutinating activity of BCV, is a less efficient hemagglutinin; it agglutinates mouse and rat erythrocytes, but in contrast to S protein, it is unable to agglutinate chicken erythrocytes, which contain a lower level of Neu5,9Ac2 on their surface. S protein is proposed to be responsible for the primary attachment of virus to cell surface. S protein is proposed to be responsible for the primary attachement of virus to cell surface receptors. The potential of S protein as a probe for the detection of Neu5,9Ac2-containing glycoconjugates is demonstrated.

  19. Molecular identification of GD3 as a suppressor of the innate immune response in ovarian cancer

    PubMed Central

    Webb, Tonya J.; Li, Xiangming; Giuntoli, Robert L.; Lopez, Pablo H.H.; Heuser, Christoph; Schnaar, Ronald L.; Tsuji, Moriya; Kurts, Christian; Oelke, Mathias; Schneck, Jonathan P.

    2012-01-01

    Tumors often display mechanisms to avoid or suppress immune recognition. One such mechanism is the shedding of gangliosides into the local tumor microenvironment, and a high concentration of circulating gangliosides is associated with poor prognosis. In this study, we identify ganglioside GD3, which was isolated from the polar lipid fraction of ovarian cancer-associated ascites, as an inhibitory factor that prevents innate immune activation of natural killer T (NKT) cells. Purified GD3 displayed a high affinity for both human and mouse CD1d, a molecule involved in the presentation of lipid antigens to T cells. Purified GD3, as well as substances within the ascites, bound to the CD1d antigenic binding site and did not require additional processing for its inhibitory effect on NKT cells. Importantly, in vivo administration of GD3 inhibited α-GalCer- induced NKT cell activation in a dose dependent manner. These data therefore indicate that ovarian cancer tumors may use GD3 to inhibit the anti-tumor NKT cell response as an early mechanism of tumor immune evasion. PMID:22649190

  20. 9-O-acetylated sialic acids differentiating normal haematopoietic precursors from leukemic stem cells with high aldehyde dehydrogenase activity in children with acute lymphoblastic leukaemia.

    PubMed

    Chowdhury, Suchandra; Chandra, Sarmila; Mandal, Chitra

    2014-10-01

    Childhood acute lymphoblastic leukaemia (ALL) originates from mutations in haematopoietic progenitor cells (HPCs). For high-risk patients, treated with intensified post-remission chemotherapy, haematopoietic stem cell (HSC) transplantation is considered. Autologous HSC transplantation needs improvisation till date. Previous studies established enhanced disease-associated expression of 9-O-acetylated sialoglycoproteins (Neu5,9Ac2-GPs) on lymphoblasts of these patients at diagnosis, followed by its decrease with clinical remission and reappearance with relapse. Based on this differential expression of Neu5,9Ac2-GPs, identification of a normal HPC population was targeted from patients at diagnosis. This study identifies two distinct haematopoietic progenitor populations from bone marrow of diagnostic ALL patients, exploring the differential expression of Neu5,9Ac2-GPs with stem cell (CD34, CD90, CD117, CD133), haematopoietic (CD45), lineage-commitment (CD38) antigens and cytosolic aldehyde dehydrogenase (ALDH). Normal haematopoietic progenitor cells (ALDH(+)SSC(lo)CD45(hi)Neu5,9Ac2 -GPs(lo)CD34(+)CD38(-)CD90(+)CD117(+)CD133(+)) differentiated into morphologically different, lineage-specific colonies, being crucial for autologous HSC transplantation while leukemic stem cells (ALDH(+)SSC(lo)CD45(lo)Neu5,9Ac2 -GPs(hi)CD34(+)CD38(+)CD90(-)CD117(-)CD133(-)) lacking this ability can be potential targets for minimal residual disease detection and drug-targeted immunotherapy.

  1. GD3 Synthase regulates epithelial-mesenchymal transition and metastasis in breast cancer

    PubMed Central

    Sarkar, Tapasree Roy; Battula, Venkata L; Werden, Steven J; Vijay, Geraldine V; Ramirez-Peña, Esmeralda Q; Taube, Joseph H; Chang, Jeffrey T; Miura, Naoyuki; Porter, Weston; Sphyris, Nathalie; Andreeff, Michael; Mani, Sendurai A

    2014-01-01

    The epithelial-mesenchymal transition (EMT) bestows cancer cells with increased stem cell properties and metastatic potential. To date, multiple extracellular stimuli and transcription factors have been shown to regulate EMT. Many of them are not druggable and therefore it is necessary to identify targets, which can be inhibited using small molecules to prevent metastasis. Recently, we identified the ganglioside GD2 as a novel breast cancer stem cell marker. Moreover, we found that GD3 synthase (GD3S)—an enzyme involved in GD2 biosynthesis—is critical for GD2 production and could serve as a potential druggable target for inhibiting tumor initiation and metastasis. Indeed, there is a small-molecule known as triptolide that has been shown to inhibit GD3S function. Accordingly, in this manuscript, we demonstrate that the inhibition of GD3S using shRNA or triptolide compromises the initiation and maintenance of EMT instigated by various signaling pathways, including Snail, Twist and TGF-β1 as well as the mesenchymal characteristics of claudin-low breast cancer cell lines (SUM159 and MDA-MB-231). Moreover, GD3S is necessary for wound healing, migration, invasion and stem cell properties in vitro. Most importantly, inhibition of GD3S in vivo prevents metastasis in experimental as well as in spontaneous syngeneic wild-type mouse models. We also demonstrate that the transcription factor FOXC2, a central downstream mediator/effector of several EMT pathways, directly regulates GD3S expression by binding to its promoter. In clinical specimens, the expression of GD3S correlates with poor prognosis in triple negative human breast tumors. Moreover, GD3S expression correlates with activation of the c-Met signaling pathway leading to increased stem cell properties and metastatic competence. Collectively, these findings suggest that the GD3S-c-Met axis could serve as an effective target for the treatment of metastatic breast cancers. PMID:25109336

  2. Neuromuscular synaptic function in mice lacking major subsets of gangliosides.

    PubMed

    Zitman, F M P; Todorov, B; Jacobs, B C; Verschuuren, J J; Furukawa, K; Furukawa, K; Willison, H J; Plomp, J J

    2008-10-28

    Gangliosides are a family of sialylated glycosphingolipids enriched in the outer leaflet of neuronal membranes, in particular at synapses. Therefore, they have been hypothesized to play a functional role in synaptic transmission. We have measured in detail the electrophysiological parameters of synaptic transmission at the neuromuscular junction (NMJ) ex vivo of a GD3-synthase knockout mouse, expressing only the O- and a-series gangliosides, as well as of a GM2/GD2-synthase*GD3-synthase double-knockout (dKO) mouse, lacking all gangliosides except GM3. No major synaptic deficits were found in either null-mutant. However, some extra degree of rundown of acetylcholine release at high intensity use was present at the dKO NMJ and a temperature-specific increase in acetylcholine release at 35 degrees C was observed in GD3-synthase knockout NMJs, compared with wild-type. These results indicate that synaptic transmission at the NMJ is not crucially dependent on the particular presence of most ganglioside family members and remains largely intact in the sole presence of GM3 ganglioside. Rather, presynaptic gangliosides appear to play a modulating role in temperature- and use-dependent fine-tuning of transmitter output. PMID:18801416

  3. Identification of N-acetylneuraminic acid and its 9-O-acetylated derivative on the cell surface of Cryptococcus neoformans: influence on fungal phagocytosis.

    PubMed

    Rodrigues, M L; Rozental, S; Couceiro, J N; Angluster, J; Alviano, C S; Travassos, L R

    1997-12-01

    Sialic acids from sialoglycoconjugates present at the cell surface of Cryptococcus neoformans yeast forms were analyzed by high-performance thin-layer chromatography, binding of influenza A and C virus strains, enzymatic treatment, and flow cytofluorimetry with fluorescein isothiocyanate-labeled lectins. C. neoformans yeast forms grown in a chemically defined medium contain N-acetylneuraminic acid and its 9-O-acetylated derivative. A density of 3 x 10(6) residues of sialic acid per cell was found in C. neoformans. Sialic acids in cryptococcal cells are glycosidically linked to galactopyranosyl units as inferred from the increased reactivity of neuraminidase-treated yeasts with peanut agglutinin. N-Acetylneuraminic acids are alpha-2,6 and alpha-2,3 linked, as indicated by using virus strains M1/5 and M1/5 HS8, respectively, as agglutination probes. The alpha-2,6 linkage markedly predominated. These findings were essentially confirmed by the interaction of cryptococcal cells with the lectins Sambucus nigra agglutinin and Maackia amurensis agglutinin. We also investigated whether the sialyl residues present in C. neoformans are involved in the fungal interaction with a cationic solid-phase substrate and with mouse resident macrophages. Adhesion of yeast cells to poly-L-lysine was mediated, in part, by sialic acid residues, since the number of adherent cells was markedly reduced after treatment with bacterial neuraminidase. The enzymatic removal of sialic acids also made C. neoformans yeast cells more susceptible to endocytosis by macrophages. The results show that sialic acids are components of the cryptococcal cell surface that contribute to its negative charge and protect yeast forms against phagocytosis.

  4. Identification of N-acetylneuraminic acid and its 9-O-acetylated derivative on the cell surface of Cryptococcus neoformans: influence on fungal phagocytosis.

    PubMed Central

    Rodrigues, M L; Rozental, S; Couceiro, J N; Angluster, J; Alviano, C S; Travassos, L R

    1997-01-01

    Sialic acids from sialoglycoconjugates present at the cell surface of Cryptococcus neoformans yeast forms were analyzed by high-performance thin-layer chromatography, binding of influenza A and C virus strains, enzymatic treatment, and flow cytofluorimetry with fluorescein isothiocyanate-labeled lectins. C. neoformans yeast forms grown in a chemically defined medium contain N-acetylneuraminic acid and its 9-O-acetylated derivative. A density of 3 x 10(6) residues of sialic acid per cell was found in C. neoformans. Sialic acids in cryptococcal cells are glycosidically linked to galactopyranosyl units as inferred from the increased reactivity of neuraminidase-treated yeasts with peanut agglutinin. N-Acetylneuraminic acids are alpha-2,6 and alpha-2,3 linked, as indicated by using virus strains M1/5 and M1/5 HS8, respectively, as agglutination probes. The alpha-2,6 linkage markedly predominated. These findings were essentially confirmed by the interaction of cryptococcal cells with the lectins Sambucus nigra agglutinin and Maackia amurensis agglutinin. We also investigated whether the sialyl residues present in C. neoformans are involved in the fungal interaction with a cationic solid-phase substrate and with mouse resident macrophages. Adhesion of yeast cells to poly-L-lysine was mediated, in part, by sialic acid residues, since the number of adherent cells was markedly reduced after treatment with bacterial neuraminidase. The enzymatic removal of sialic acids also made C. neoformans yeast cells more susceptible to endocytosis by macrophages. The results show that sialic acids are components of the cryptococcal cell surface that contribute to its negative charge and protect yeast forms against phagocytosis. PMID:9393779

  5. Ganglioside Biochemistry

    PubMed Central

    Kolter, Thomas

    2012-01-01

    Gangliosides are sialic acid-containing glycosphingolipids. They occur especially on the cellular surfaces of neuronal cells, where they form a complex pattern, but are also found in many other cell types. The paper provides a general overview on their structures, occurrence, and metabolism. Key functional, biochemical, and pathobiochemical aspects are summarized. PMID:25969757

  6. b-Series gangliosides crucially regulate leptin secretion in adipose tissues.

    PubMed

    Ji, Shuting; Ohkawa, Yuki; Tokizane, Kyohei; Ohmi, Yuhsuke; Banno, Ryoichi; Furukawa, Keiko; Kiyama, Hiroshi; Furukawa, Koichi

    2015-04-01

    Gangliosides are widely involved in the regulation of cells and organs. However, little is known about their roles in leptin secretion from adipose tissues. Genetic deletion of b-series gangliosides resulted in the marked reduction of serum leptin. Expression analysis of leptin revealed that leptin accumulated in the adipose tissues of GD3 synthase-knockout (GD3S KO) mice. Analysis of primary cultured stromal vascular fractions (SVF) derived from GD3S KO mice revealed that leptin secretion was reduced, although leptin amounts in cells were increased compared with those of wild type. Interestingly, addition of b-series gangliosides to the culture medium of differentiated SVF resulted in the restoration of leptin secretion. Results of methyl-β-cyclodextrin treatment of differentiated 3T3-L1 cells as well as immunocytostaining of leptin and caveolin-1 suggested that b-series gangliosides regulate the leptin secretion from adipose tissues in lipid rafts.

  7. Gangliosides inhibit the development from monocytes to dendritic cells

    PubMed Central

    WÖLFL, M; BATTEN, W Y; POSOVSZKY, C; BERNHARD, H; BERTHOLD, F

    2002-01-01

    Dendritic cell (DC) development and function is critical in the initiation phase of any antigen-specific immune response against tumours. Impaired function of DC is one explanation as to how tumours escape immunosurveillance. In the presence of various soluble tumour-related factors DC precursors lose their ability to differentiate into mature DC and to activate T cells. Gangliosides are glycosphingolipids shed by tumours of neuroectodermal origin such as melanoma and neuroblastoma. In this investigation we address the question of whether gangliosides suppress the development and function of monocyte-derived DC in vitro. In the presence of gangliosides, the monocytic DC precursors showed increased adherence, cell spreading and a reduced number of dendrites. The expression of MHC class II molecules, co-stimulatory molecules and the GM-CSF receptor (CD116) on the ganglioside-treated DC was significantly reduced. Furthermore, the function of ganglioside-treated DC was impaired as observed in endocytosis, chemotactic and T cell proliferation assays. In contrast to monocytic DC precursors, mature DC were unaffected even when higher doses of gangliosides were added to the culture. With regard to their carbohydrate structure, five different gangliosides (GM2, GM3, GD2, GD3, GT1b), which are typically shed by melanoma and neuroblastoma, were tested for their ability to suppress DC development and function. Suppression was induced by GM2, but not by the other gangliosides. These data suggest that certain gangliosides impair DC precursors, implying a possible mechanism for tumour escape. PMID:12452834

  8. Neuromuscular synaptic transmission in aged ganglioside-deficient mice.

    PubMed

    Zitman, Femke M P; Todorov, Boyan; Verschuuren, Jan J; Jacobs, Bart C; Furukawa, Keiko; Furukawa, Koichi; Willison, Hugh J; Plomp, Jaap J

    2011-01-01

    Gangliosides are sialylated glycosphingolipids that are present in high density on neuronal membranes, especially at synapses, where they are assumed to play functional or modulating roles. Mice lacking GM2/GD2-synthase express only the simple gangliosides GD3 and GM3 and develop progressive motor behaviour deficits upon ageing, apparently due to failing complex ganglioside-dependent maintenance and/or repair processes or, alternatively, toxic GM3/GD3 accumulation. We investigated the function of neuromuscular junctions (NMJs) of aged (>9 month-old) GM2/GD2-synthase null-mutant mice, because synaptic dysfunction might develop with age and could potentially contribute to the late-onset motor phenotype. In addition, we studied NMJs of old mice lacking GD3-synthase (expressing only O- and a-series gangliosides), which do not show an overt neurological phenotype but may develop subclinical synaptic deficits. Detailed electrophysiological analyses showed subtle changes in presynaptic neurotransmitter release. Acetylcholine release at 40 Hz nerve stimulation at aged GM2/GD2-synthase null-mutant NMJs ran down slightly more pronounced than at wild-type NMJs, and spontaneous acetylcholine release rate at GD3-synthase null-mutant NMJs was somewhat higher than at wild-type, selectively at 25 °C bath temperature. Interestingly, we observed faster kinetics of postsynaptic electrophysiological responses at aged GD3-synthase null-mutant NMJs, not previously seen by us at NMJs of young GD3-synthase null-mutants or other types of (aged or young) ganglioside-deficient mice. These kinetic changes might reflect a change in postsynaptic acetylcholine receptor behaviour. Our data indicate that it is highly unlikely that transmission failure at NMJs contributes to the progressive motor defects of aged GM2/GD2-synthase null-mutants and that, despite some kinetic changes of synaptic signals, neuromuscular transmission remains successful in aged GD3-synthase null-mutant mice. Apparently

  9. Changes of the ganglioside pattern and content in human fibroblasts by high density cell population subculture progression.

    PubMed

    Sciannamblo, Mariateresa; Chigorno, Vanna; Passi, Alberto; Valaperta, Rea; Zucchi, Ileana; Sonnino, Sandro

    2002-03-01

    In this study we show that the ganglioside content and pattern of human skin fibroblasts change along the process of cell subculture progression by varying the cell density. GM3, GD3 and GD1a were components of the total cell ganglioside mixtures extracted from cells, but GD1a was in all the extracts a minor component or very scant. Other gangliosides present in traces were not characterised. The fibroblast ganglioside content of 52 pools of cells obtained from 5 different cell lines cultured at variable cell density ranged from 2.0 to 13.1 nmoles per mg of cell protein. The molar ratio between GM3 and GD3 varied from 418 to 0.6 in the ganglioside mixtures, as determined by densitometric quantitative analysis after thin layer chromatographic separation. Both the ganglioside content and the GM3/GD3 molar ratio were constant along several passages of subculture progression performed by plating cells collected at confluence. Instead, when the subculture progression was performed by plating cells collected at a few days after reaching confluence, a progressive increase of the ganglioside content was observed. GD3 increased proportionally more than GM3 so that a progressive decrease of the ratio between GM3 and GD3 was observed. In some experiments, GD3 was very scant at the beginning of the progression, while it was near 30% after 5 passages under these conditions. The progressive increase of GD3 along the high density cell population subculture progression was associated to a moderate increase of the mRNA GD3 synthase.

  10. Ganglioside conjugate vaccines. Immunotherapy against tumors of neuroectodermal origin.

    PubMed

    Helling, F; Livingston, P O

    1994-01-01

    Gangliosides are known to be suitable targets for immune attack against cancer but they are poorly immunogenic. Active immunization with ganglioside/BCG or liposome vaccines results in moderate titer IgM antibody responses of short duration. Covalent attachment of poorly immunogenic antigens to immunogenic proteins is a potent method for inducing an IgG antibody response. GD3, a dominant ganglioside on malignant melanoma, was modified by ozone cleavage of the double bond in the ceramide backbone, an aldehyde group introduced and used for coupling via reductive amination to epsilon-amino-lysyl groups of proteins. Utilizing this method, GD3 conjugates were constructed with: 1. Synthetic multiple antigenic peptide (MAP) constructs expressing 4 repeats of a malaria T-cell epitope; 2. Outer membrane proteins (OMP) of Neisseria meningitidis; 3. Cationized bovine serum albumin; 4. Keyhole limpet hemocyanin (KLH); and 5. Polylysine. In addition, conjugates containing only the GD3 oligosaccharide were synthesized. All constructs were tested for antigenicity using anti-GD3 antibody R24, and for immunogenicity in mice. Serum antibody levels were analyzed by ELISA and immune thin-layer chromatography. Results in the mouse show a significant improvement in the IgM antibody response and a consistent IgG response against GD3 using GD3-KLH conjugates. Other carrier proteins and the use of GD3 oligosaccharide were significantly less effective. If improved immunogenicity and clinical benefit with conjugate vaccines can be demonstrated in patients with melanoma, this approach may be applicable to patients with other tumors of neuroectodermal origin, including gliomas, glioblastomas, astrocytomas, and neuroblastomas.

  11. Effect of Dietary Complex Lipids on the Biosynthesis of Piglet Brain Gangliosides.

    PubMed

    Reis, Marlon M; Bermingham, Emma N; Reis, Mariza G; Deb-Choudhury, Santanu; MacGibbon, Alastair; Fong, Bertram; McJarrow, Paul; Bibiloni, Rodrigo; Bassett, Shalome A; Roy, Nicole C

    2016-02-17

    Gangliosides, found in mammalian milk, are known for their roles in brain development of the newborn. However, the mechanism involved in the impact of dietary gangliosides on brain metabolism is not fully understood. The impact of diets containing complex lipids rich in milk-derived ganglioside GD3 on the biosynthesis of gangliosides (assessed from the incorporation of deuterium) in the frontal lobe of a piglet model is reported. Higher levels of incorporation of deuterium was observed in the GM1 and GD1a containing stearic acid in samples from piglets fed milk containing 18.2 μg/mL of GD3 compared to that in those fed milk containing 25 μg/mL of GD3. This could suggest that the gangliosides from the diet may be used as a precursor for de novo biosynthesis of brain gangliosides or lead to the reduction of de novo biosynthesis of these gangliosides. This effect was more pronounced in the left compared to that in the right brain hemisphere.

  12. [Gangliosides and cancer].

    PubMed

    Dumontet, C; Portoukalian, J

    1991-01-01

    Gangliosides are glycosphingolipids which contain neuraminic acid. Although they are present in the plasma membranes of all cells, gangliosides are expressed differently, both quantitatively and qualitatively, in certain types of cancer. Modifications in ganglioside composition may account for some of the abnormal interactions between these tumor cells and their environment. Furthermore, some of the gangliosides are shed by tumor cells and may modify host immunity, thus contributing to the development of tumors. In cases of melanoma and neuroblastoma, the modifications in ganglioside expression are such that gangliosides may be used both as tumor markers and as targets for immunotherapy.

  13. GD3+ cells in the adult rat optic nerve are ramified microglia rather than O-2Aadult progenitor cells.

    PubMed

    Wolswijk, G

    1994-04-01

    The adult central nervous system (CNS) contains a population of adult oligodendrocyte-type-2 astrocyte (O-2A) progenitor cells (O-2Aadult progenitor cells). These cells may provide a source of the new oligodendrocytes that are needed to repair demyelinated lesions. In order to examine the role of O-2Aadult progenitor cells in the regeneration of the oligodendrocyte population following demyelinating damage, it is essential to be able to identify such cells unambiguously in sections of adult CNS tissue. The present study examined whether antibodies to the ganglioside GD3 specifically label O-2Aadult progenitor cells in cultures and sections of adult optic nerve, since previous studies on the developing CNS had suggested that O-2Aperinatal progenitor cells were GD3+ in vitro and in vivo. Evidence is presented indicating that, although O-2Aadult progenitor cells in vitro were labelled with the R24 mAb (an anti-GD3 mAb), all GD3+ cells in sections of adult optic nerve bound the OX-42 mAb and the B4 isolectin derived from Griffonia Simplicifolia, and thus were not O-2Aadult progenitor cells, but ramified microglia. The data suggest that O-2Aadult progenitor cells become GD3+ when placed in culture and that ramified microglia lose GD3-expression in vitro.

  14. [Gangliosides in neurological pharmacotherapy].

    PubMed

    Małecki, A; Małecka, E; Trzeciak, H I

    1992-01-01

    Gangliosides take part in synaptic transmission, neuronal metabolism and development of nervous tissue. They cooperate with nerve growth factor (NGF) and have positive influence on regeneration of the nervous system impairments. There exist many behavioural and biochemical evidences of gangliosides participation in the regeneration of experimentally injured animal nervous system. The therapeutic effectivity of gangliosides in clinical practice is encouraging. Commercial preparates of gangliosides (Cronassial, Sygen) have been successfully used in the therapy of chronic neuropathies, strokes and subarachnoidal haemorrhages. Among the adverse reactions to these drugs are: local irritation, anxiety and possible detrimental effect in immunological system. Ganglioside preparations need further clinical examinations. PMID:1291908

  15. Production of Multiple Brain-Like Ganglioside Species Is Dispensable for Fas-Induced Apoptosis of Lymphoid Cells

    PubMed Central

    Carpentier, Stéphane; Levade, Thierry; Cuvillier, Olivier; Portoukalian, Jacques

    2011-01-01

    Activation of an acid sphingomyelinase (aSMase) leading to a biosynthesis of GD3 disialoganglioside has been associated with Fas-induced apoptosis of lymphoid cells. The present study was undertaken to clarify the role of this enzyme in the generation of gangliosides during apoptosis triggered by Fas ligation. The issue was addressed by using aSMase-deficient and aSMase-corrected cell lines derived from Niemann-Pick disease (NPD) patients. Fas cross-linking elicited a rapid production of large amounts of complex a- and b-series species of gangliosides with a pattern and a chromatographic behavior as single bands reminiscent of brain gangliosides. The gangliosides were synthesized within the first ten minutes and completely disappeared within thirty minutes after stimulation. Noteworthy is the observation that GD3 was not the only ganglioside produced. The production of gangliosides and the onset of apoptotic hallmarks occurred similarly in both aSMase-deficient and aSMase-corrected NPD lymphoid cells, indicating that aSMase activation is not accountable for ganglioside generation. Hampering ganglioside production by inhibiting the key enzyme glucosylceramide synthase did not abrogate the apoptotic process. In addition, GM3 synthase-deficient lymphoid cells underwent Fas-induced apoptosis, suggesting that gangliosides are unlikely to play an indispensable role in transducing Fas-induced apoptosis of lymphoid cells. PMID:21629700

  16. Essential roles of integrin-mediated signaling for the enhancement of malignant properties of melanomas based on the expression of GD3

    SciTech Connect

    Ohkawa, Yuki; Miyazaki, Sayaka; Miyata, Maiko; Hamamura, Kazunori; Furukawa, Koichi Furukawa, Keiko

    2008-08-15

    We reported that ganglioside GD3 enhances cell proliferation and invasion of melanomas causing stronger tyrosine-phosphorylation of p130Cas and paxillin after stimulation with fetal calf serum. Besides signals via growth factor/receptor, adhesion signals via integrin might be also enhanced by GD3. Here, roles of integrin-mediated signaling in the cell proliferation and invasion, and in the activation of adaptor molecules were examined, showing that integrin was also important for the cell growth and invasion. p130Cas and paxillin underwent stronger tyrosine-phosphorylation in GD3+ cells than in GD3- cells during the adhesion in the absence of serum. On the other hand, no proteins underwent tyrosine phosphorylation in GD3+ and GD3- cells in a suspension state when stimulated with fetal calf serum. These results suggested that integrin-mediated signaling is essential in the effects of GD3 on the malignant properties of melanomas. Co-localization of GD3 and integrin at the focal adhesion supported these results.

  17. Expression of GD3 disialoganglioside antigen on peripheral T-lymphocytes in patients with disseminated malignant melanoma.

    PubMed

    Welte, B; Handgretinger, R; Rassner, G; Fierlbeck, G

    1997-04-01

    Disialoganglioside antigens GD2 and GD3 are expressed on most melanoma cells. On melanoma surrounding T-cells in immunohistological sections, disialogangliosides can also be found, as well as in a small % of T-lymphocytes in peripheral blood from healthy persons. In order to find out if there is a difference in ganglioside expression on peripheral T-lymphocytes between melanoma patients and healthy persons, we examined the expression of CD3 as T-lymphocytic antigen and GD2 or GD3 antigens, respectively, by flow cytometry. We used peripheral mononuclear blood cells of 12 patients with advanced disseminated malignant melanoma and of 12 healthy control donors. For immunostaining, murine monoclonal antibodies Leu-4, 14G2a and MB3.6 were used, recognizing CD3, GD2 and GD3. GD2 expression was found on only a low proportion of T-lymphocytes in patients and healthy persons (pat.: mean = 1.2% +/- 0.7%, co.: mean = 0.4% +/- 0.4%). Disialoganglioside antigen GD3, however, could be demonstrated on an average of 8.4% +/- 4.6% of patients' and on 4.0% +/- 2.1% of healthy persons' T-cells. There is a statistically significant difference (P < 0.01) between the data of patients' and control group. We conclude that there is a correlation between advanced malignant melanoma and expression of GD3 antigen on patients' peripheral T-lymphocytes. The immunological relevance of our findings is discussed. PMID:9209886

  18. Effect of Gd3+ on the colloidal stability of liposomes.

    PubMed

    Sabín, Juan; Prieto, Gerardo; Sennato, Simona; Ruso, Juan M; Angelini, Roberta; Bordi, Federico; Sarmiento, Félix

    2006-09-01

    Lanthanide ions such as La3+ and Gd3+ are well known to have large effects on the structure of phospholipid membranes. Unilamellar vesicles of dipalmitoylphosphatidylcholine (DPPC) were prepared by sonication method and confirmed by transmission electron microscopy. The effects of concentration of gadolinium ions Gd3+ on DPPC unilamellar vesicles in aqueous media were studied by different techniques. As physical techniques, photon correlation spectroscopy, electrophoretic mobility, and differential scanning calorimetry were used. The theoretical predictions of the colloidal stability of liposomes were followed using the Derjaguin-Landau-Verwey-Overbeek theory. Changes in the size of liposomes and high polydispersities values were observed as Gd3+ concentration increases, suggesting that this cation induces the aggregation of vesicles. Electrophoretic mobility measurements on unilamellar vesicles as a function of Gd3+ ion concentration show that the vesicles adsorb Gd3+ ions. Above Gd3+ concentrations of 0.1 mol dm-3, the zeta potential and light scattering measurements indicate the beginning of aggregation process. For comparison with similar phospholipids, the zeta potential of phosphatidylcholine interacting with Gd3+ was measured, showing an analogous behavior. Differential scanning calorimetry has been used to determine the effect of Gd3+ on the transition temperature (Tc) and on the enthalpy (DeltaHc) associated with the process.

  19. Ganglioside GD2 identifies breast cancer stem cells and promotes tumorigenesis

    PubMed Central

    Battula, Venkata Lokesh; Shi, Yuexi; Evans, Kurt W.; Wang, Rui-Yu; Spaeth, Erika L.; Jacamo, Rodrigo O.; Guerra, Rudy; Sahin, Aysegul A.; Marini, Frank C.; Hortobagyi, Gabriel; Mani, Sendurai A.; Andreeff, Michael

    2012-01-01

    Cancer stem cells (CSCs) are a small subpopulation of cancer cells that have increased resistance to conventional therapies and are capable of establishing metastasis. However, only a few biomarkers of CSCs have been identified. Here, we report that ganglioside GD2 (a glycosphingolipid) identifies a small fraction of cells in human breast cancer cell lines and patient samples that are capable of forming mammospheres and initiating tumors with as few as 10 GD2+ cells. In addition, the majority of GD2+ cells are also CD44hiCD24lo, the previously established CSC-associated cell surface phenotype. Gene expression analysis revealed that GD3 synthase (GD3S) is highly expressed in GD2+ as well as in CD44hiCD24lo cells and that interference with GD3S expression, either by shRNA or using a pharmacological inhibitor, reduced the CSC population and CSC-associated properties. GD3S knockdown completely abrogated tumor formation in vivo. Also, induction of epithelial-mesenchymal transition (EMT) in transformed human mammary epithelial cells (HMLER cells) dramatically increased GD2 as well as GD3S expression in these cells, suggesting a role of EMT in the origin of GD2+ breast CSCs. In summary, we identified GD2 as a new CSC-specific cell surface marker and GD3S as a potential therapeutic target for CSCs, with the possibility of improving survival and cure rates in patients with breast cancer. PMID:22585577

  20. Overcoming artificial broadening in Gd(3+)-Gd(3+) distance distributions arising from dipolar pseudo-secular terms in DEER experiments.

    PubMed

    Cohen, Marie Ramirez; Frydman, Veronica; Milko, Petr; Iron, Mark A; Abdelkader, Elwy H; Lee, Michael D; Swarbrick, James D; Raitsimring, Arnold; Otting, Gottfried; Graham, Bim; Feintuch, Akiva; Goldfarb, Daniella

    2016-05-14

    By providing accurate distance measurements between spin labels site-specifically attached to bio-macromolecules, double electron-electron resonance (DEER) spectroscopy provides a unique tool to probe the structural and conformational changes in these molecules. Gd(3+)-tags present an important family of spin-labels for such purposes, as they feature high chemical stability and high sensitivity in high-field DEER measurements. The high sensitivity of the Gd(3+) ion is associated with its high spin (S = 7/2) and small zero field splitting (ZFS), resulting in a narrow spectral width of its central transition at high fields. However, under the conditions of short distances and exceptionally small ZFS, the weak coupling approximation, which is essential for straightforward DEER data analysis, becomes invalid and the pseudo-secular terms of the dipolar Hamiltonian can no longer be ignored. This work further explores the effects of pseudo-secular terms on Gd(3+)-Gd(3+) DEER measurements using a specifically designed ruler molecule; a rigid bis-Gd(3+)-DOTA model compound with an expected Gd(3+)-Gd(3+) distance of 2.35 nm and a very narrow central transition at the W-band (95 GHz). We show that the DEER dipolar modulations are damped under the standard W-band DEER measurement conditions with a frequency separation, Δν, of 100 MHz between the pump and observe pulses. Consequently, the DEER spectrum deviates considerably from the expected Pake pattern. We show that the Pake pattern and the associated dipolar modulations can be restored with the aid of a dual mode cavity by increasing Δν from 100 MHz to 1.09 GHz, allowing for a straightforward measurement of a Gd(3+)-Gd(3+) distance of 2.35 nm. The increase in Δν increases the contribution of the |-5/2〉→|-3/2〉 and |-7/2〉→|-5/2〉 transitions to the signal at the expense of the |-3/2 〉→|-1/2〉 transition, thus minimizing the effect of dipolar pseudo-secular terms and restoring the validity of the weak

  1. Overcoming artificial broadening in Gd(3+)-Gd(3+) distance distributions arising from dipolar pseudo-secular terms in DEER experiments.

    PubMed

    Cohen, Marie Ramirez; Frydman, Veronica; Milko, Petr; Iron, Mark A; Abdelkader, Elwy H; Lee, Michael D; Swarbrick, James D; Raitsimring, Arnold; Otting, Gottfried; Graham, Bim; Feintuch, Akiva; Goldfarb, Daniella

    2016-05-14

    By providing accurate distance measurements between spin labels site-specifically attached to bio-macromolecules, double electron-electron resonance (DEER) spectroscopy provides a unique tool to probe the structural and conformational changes in these molecules. Gd(3+)-tags present an important family of spin-labels for such purposes, as they feature high chemical stability and high sensitivity in high-field DEER measurements. The high sensitivity of the Gd(3+) ion is associated with its high spin (S = 7/2) and small zero field splitting (ZFS), resulting in a narrow spectral width of its central transition at high fields. However, under the conditions of short distances and exceptionally small ZFS, the weak coupling approximation, which is essential for straightforward DEER data analysis, becomes invalid and the pseudo-secular terms of the dipolar Hamiltonian can no longer be ignored. This work further explores the effects of pseudo-secular terms on Gd(3+)-Gd(3+) DEER measurements using a specifically designed ruler molecule; a rigid bis-Gd(3+)-DOTA model compound with an expected Gd(3+)-Gd(3+) distance of 2.35 nm and a very narrow central transition at the W-band (95 GHz). We show that the DEER dipolar modulations are damped under the standard W-band DEER measurement conditions with a frequency separation, Δν, of 100 MHz between the pump and observe pulses. Consequently, the DEER spectrum deviates considerably from the expected Pake pattern. We show that the Pake pattern and the associated dipolar modulations can be restored with the aid of a dual mode cavity by increasing Δν from 100 MHz to 1.09 GHz, allowing for a straightforward measurement of a Gd(3+)-Gd(3+) distance of 2.35 nm. The increase in Δν increases the contribution of the |-5/2〉→|-3/2〉 and |-7/2〉→|-5/2〉 transitions to the signal at the expense of the |-3/2 〉→|-1/2〉 transition, thus minimizing the effect of dipolar pseudo-secular terms and restoring the validity of the weak

  2. Space solidification experiment on Gd 3Co compound

    NASA Astrophysics Data System (ADS)

    Savitsky, E. M.; Torchinova, R. S.

    On board the orbital complex "Salyut 6" during longterm 0-gravity space flight crystallization of the polycrystal samples of the intermetallic compound Gd 3Co has been performed. The object of the present experiment was to investigate the effects of microgravity on the solidification process, final macro- and micro-structure and magnetic properties of antiferromagnetic Gd 3Co compound. The experiment included the melting of Gd 3Co under the isothermal or thermal gradient conditions followed by passive cooling. The change of meniscus form from the cave form which is characteristic of the ground-based samples to the concave form for the flight samples has been observed. The formation of the reaction layers has been found as a result of the mutual contact between liquid Gd 3Co and Ta-container in all samples investigated. The temperature dependences of the magnetization with Neel peaks have been observed for the ground-based and flight samples of Gd 3Co. Magnetization values of the flight samples were appreciably higher than those of the ground-based samples.

  3. New trends in ganglioside chemistry

    SciTech Connect

    Sonnino, S.; Ghidoni, R.; Gazzotti, G.; Acquotti, D.; Tettamanti, G.

    1988-01-01

    New methods have been developed for the preparation of highly purified gangliosides, homogeneous in the saccharide, long chain base, and fatty acid moieties and gangliosides carrying different kinds of labelled probes. Gangliosides, homogeneous in the oligosaccharide portion, were prepared by preparative normal phase HPLC on a Lichrosorb-NH-2 column, using a gradient of acetonitrile-phosphate buffer, pH 5.6, as solvent system. Each class of ganglioside (from monosialo- to tetrasialogangliosides) was then submitted to reversed phase HPLC on a preparative RP-8 column, using acetonitrile-5 mM phosphate buffer, pH 7, as solvent system, to obtain gangliosides homogeneous in the long chain base moiety. Gangliosides containing C18 and C20 sphinganine were prepared by catalytic hydrogenation of the corresponding unsaturated gangliosides. GM1 with homogeneous acyl chain was prepared by alkaline hydrolysis in the presence of tetramethylammonium hydroxide, followed by re-N-acylation, carried out in the presence of dimethylaminopropyl, ethylcarbodiimide and natural fatty acids, or of mixed anhydride of ethylchloroformate and 14C-stearic acid, and re-N-acetylation performed with acetic anhydride or labelled acetic anhydride. The GM1 derivative, de-acetylated at the level of sialic acid, also produced by alkaline treatment of GM1, was submitted to re-N-acetylation with 14C-acetic anhydride to produce specifically 14C-labelled GM1. Re-N-acylation was carried out a) in the presence of dimethylaminopropyl, ethylcarbodiimide and natural fatty acids, b) with mixed anhydride of ethylchloroformate and 14C-stearic acid. After re-N-acylations, re-N-acetylation was performed with acetic anhydride or labelled acetic anhydride. 53 references.

  4. The new structure type Gd3Ni7Al14.

    PubMed

    Pukas, Svitlana; Gladyshevskii, Roman

    2015-11-01

    The crystal structure of Gd3Ni7Al14 (trigadolinium heptanickel tetradecaaluminide) belongs to a family of two-layer structures and can be described as an assembly of interpenetrating centred straight prisms. For the Ni atoms, trigonal prisms (Al4Gd2 and Al6) are observed, the Al atoms are inside tetragonal (Ni2Al2Gd4, Ni2Al4Gd2, Al4Gd4, Ni4Al4 and Al8) and pentagonal (Ni4Al6 and Al10) prisms, while the Gd atoms are at the centres of pentagonal (Ni4Al6) and hexagonal (Ni4Al8) prisms. In each case, the true coordination polyhedron is a capped prism, also including atoms from the same layer. The structural features of Gd3Ni7Al14 are similar to those of the intermetallides PrNi2Al3 and ZrNiAl. In all these structures, Ni-centred trigonal prisms form infinite columns via common triangular faces. The columns share prism edges and form a three-dimensional framework with six-membered rings in the (001) plane in the case of the PrNi2Al3 and ZrNiAl types. In the case of Gd3Ni7Al14, six-membered rings are also observed, but only two-thirds of the rings are interconnected via prism edges. PMID:26524174

  5. The new structure type Gd3Ni7Al14.

    PubMed

    Pukas, Svitlana; Gladyshevskii, Roman

    2015-11-01

    The crystal structure of Gd3Ni7Al14 (trigadolinium heptanickel tetradecaaluminide) belongs to a family of two-layer structures and can be described as an assembly of interpenetrating centred straight prisms. For the Ni atoms, trigonal prisms (Al4Gd2 and Al6) are observed, the Al atoms are inside tetragonal (Ni2Al2Gd4, Ni2Al4Gd2, Al4Gd4, Ni4Al4 and Al8) and pentagonal (Ni4Al6 and Al10) prisms, while the Gd atoms are at the centres of pentagonal (Ni4Al6) and hexagonal (Ni4Al8) prisms. In each case, the true coordination polyhedron is a capped prism, also including atoms from the same layer. The structural features of Gd3Ni7Al14 are similar to those of the intermetallides PrNi2Al3 and ZrNiAl. In all these structures, Ni-centred trigonal prisms form infinite columns via common triangular faces. The columns share prism edges and form a three-dimensional framework with six-membered rings in the (001) plane in the case of the PrNi2Al3 and ZrNiAl types. In the case of Gd3Ni7Al14, six-membered rings are also observed, but only two-thirds of the rings are interconnected via prism edges.

  6. ENDOR study of Gd 3+ complexes in frozen solutions

    NASA Astrophysics Data System (ADS)

    Yim, Moon B.; Makinen, Marvin W.

    The coordination environment of Gd 3+ in frozen solutions is investigated by application of electron nuclear double-resonance spectroscopy. Proton ENDOR spectra of the Gd 3+ ion in frozen methanol-water cosolvent mixtures obtained with the static laboratory magnetic field (Ha) at the turning point of the electron paramagnetic resonance absorption exhibit single-crystal-type line pairs. With use of selectively deuterated materials, the ligand origin of each pair of ENDOR lines has been assigned. For GdCl 3 there are two distinguishable types of protons due to the HO groups of metal-coordinated solvent molecules, and there is one set belonging to the methyl group of metal-coordinated methanol. Similarly, for Gd(CH 3000) 3 and Gd(CH 3CH 2000) 3, the set of ENDOR lines belonging to the methyl group of acetate and to the methylene group of propionate ligands have been identified. By analysis of the dependence of the ENDOR spectra on Ho, we have determined the values of the principal hyperfine coupling (hfc) components of each of the metal-bound ligands. The hfc components of methyl protons of Gd 3+-bound acetate and of the methylene protons of Gd 3+-bound propionate exhibit axial symmetry. Under the point-dipole approximation, they yield correspondingly calculated metal-proton distances of 4.53 and 4.42 Å in good agreement with the value of 4.73 A deduced from crystallographic data for inner sphere coordinated ligands. The hfc components of the HO protons of metal-bound solvent molecules do not exhibit axial symmetry. One set is assigned to inner sphere coordinated H2O while the other is assigned to outer sphere bound CH 30H. The metal-proton distances, calculated on the basis of the largest anisotropic hfc components as lower limit estimates, support these structural assignments. Application of ENDOR spectroscopy is made to identify the primary lanthanide binding site in a-chymotrypsin and to demonstrate the accuracy with which this method of analyzing ENDOR can be

  7. Ganglioside GD2 in reception and transduction of cell death signal in tumor cells

    PubMed Central

    2014-01-01

    Background Ganglioside GD2 is expressed on plasma membranes of various types of malignant cells. One of the most promising approaches for cancer immunotherapy is the treatment with monoclonal antibodies recognizing tumor-associated markers such as ganglioside GD2. It is considered that major mechanisms of anticancer activity of anti-GD2 antibodies are complement-dependent cytotoxicity and/or antibody-mediated cellular cytotoxicity. At the same time, several studies suggested that anti-GD2 antibodies are capable of direct induction of cell death of number of tumor cell lines, but it has not been investigated in details. In this study we investigated the functional role of ganglioside GD2 in the induction of cell death of multiple tumor cell lines by using GD2-specific monoclonal antibodies. Methods Expression of GD2 on different tumor cell lines was analyzed by flow cytometry using anti-GD2 antibodies. By using HPTLC followed by densitometric analysis we measured the amount of ganglioside GD2 in total ganglioside fractions isolated from tumor cell lines. An MTT assay was performed to assess viability of GD2-positive and -negative tumor cell lines treated with anti-GD2 mAbs. Cross-reactivity of anti-GD2 mAbs with other gangliosides or other surface molecules was investigated by ELISA and flow cytometry. Inhibition of GD2 expression was achieved by using of inhibitor for ganglioside synthesis PDMP and/or siRNA for GM2/GD2 and GD3 synthases. Results Anti-GD2 mAbs effectively induced non-classical cell death that combined features of both apoptosis and necrosis in GD2-positive tumor cells and did not affect GD2-negative tumors. Anti-GD2 mAbs directly induced cell death, which included alteration of mitochondrial membrane potential, induction of apoptotic volume decrease and cell membrane permeability. This cytotoxic effect was mediated exclusively by specific binding of anti-GD2 antibodies with ganglioside GD2 but not with other molecules. Moreover, the level of GD2

  8. Quantitative analysis of gangliosides in bovine milk and colostrum-based dairy products by ultrahigh performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Lee, Hyeyoung; German, J Bruce; Kjelden, Randy; Lebrilla, Carlito B; Barile, Daniela

    2013-10-01

    Milk gangliosides have gained considerable attention because they participate in diverse biological processes, including neural development, pathogen binding, and activation of the immune system. Herein, we present a quantitative measurement of the gangliosides present in bovine milk and other dairy products and byproducts. Ultrahigh performance liquid chromatography separation was used for high-throughput analysis and achieved a short running time without sacrificing chromatographic resolution. Dynamic multiple reaction monitoring was conducted for 12 transitions for GM3 and 12 transitions for GD3. Transitions to sialic acid fragments (m/z 290.1) were chosen for the quantitation. There was a considerable amount of gangliosides in day 2 milk (GM3, 0.98 mg/L; GD3, 15.2 mg/L) which dramatically decreased at day 15 and day 90. GM3 and GD3 were also analyzed in pooled colostrum, colostrum cream, colostrum butter, and colostrum buttermilk. The separation and analytical approaches here proposed could be integrated into the dairy industry processing adding value to side-streams. PMID:24024650

  9. Ganglioside accumulation in activated glia in the developing brain: comparison between WT and GalNAcT KO mice

    PubMed Central

    Saito, Mariko; Wu, Gusheng; Hui, Maria; Masiello, Kurt; Dobrenis, Kostantin; Ledeen, Robert W.; Saito, Mitsuo

    2015-01-01

    Our previous studies have shown accumulation of GM2 ganglioside during ethanol-induced neurodegeneration in the developing brain, and GM2 elevation has also been reported in other brain injuries and neurodegenerative diseases. Using GM2/GD2 synthase KO mice lacking GM2/GD2 and downstream gangliosides, the current study explored the significance of GM2 elevation in WT mice. Immunohistochemical studies indicated that ethanol-induced acute neurodegeneration in postnatal day 7 (P7) WT mice was associated with GM2 accumulation in the late endosomes/lysosomes of both phagocytic microglia and increased glial fibrillary acidic protein (GFAP)-positive astrocytes. However, in KO mice, although ethanol induced robust neurodegeneration and accumulation of GD3 and GM3 in the late endosomes/lysosomes of phagocytic microglia, it did not increase the number of GFAP-positive astrocytes, and the accumulation of GD3/GM3 in astrocytes was minimal. Not only ethanol, but also DMSO, induced GM2 elevation in activated microglia and astrocytes along with neurodegeneration in P7 WT mice, while lipopolysaccharide, which did not induce significant neurodegeneration, caused GM2 accumulation mainly in lysosomes of activated astrocytes. Thus, GM2 elevation is associated with activation of microglia and astrocytes in the injured developing brain, and GM2, GD2, or other downstream gangliosides may regulate astroglial responses in ethanol-induced neurodegeneration. PMID:26063460

  10. Ganglioside and Non-ganglioside Mediated Host Responses to the Mouse Polyomavirus.

    PubMed

    You, John; O'Hara, Samantha D; Velupillai, Palanivel; Castle, Sherry; Levery, Steven; Garcea, Robert L; Benjamin, Thomas

    2015-10-01

    Gangliosides serve as receptors for internalization and infection by members of the polyomavirus family. Specificity is determined by recognition of carbohydrate moieties on the ganglioside by the major viral capsid protein VP1. For the mouse polyomavirus (MuPyV), gangliosides with terminal sialic acids in specific linkages are essential. Although many biochemical and cell culture experiments have implicated gangliosides as MuPyV receptions, the role of gangliosides in the MuPyV-infected mouse has not been investigated. Here we report results of studies using ganglioside-deficient mice and derived cell lines. Knockout mice lacking complex gangliosides were completely resistant to the cytolytic and pathogenic effects of the virus. Embryo fibroblasts from these mice were likewise resistant to infection, and supplementation with specific gangliosides restored infectibility. Although lacking receptors for viral infection, cells from ganglioside-deficient mice retained the ability to respond to the virus. Ganglioside-deficient fibroblasts responded rapidly to virus exposure with a transient induction of c-fos as an early manifestation of a mitogenic response. Additionally, splenocytes from ganglioside-deficient mice responded to MuPyV by secretion of IL-12, previously recognized as a key mediator of the innate immune response. Thus, while gangliosides are essential for infection in the animal, gangliosides are not required for mitogenic responses and innate immune responses to the virus. PMID:26474471

  11. Chemoenzymatic synthesis of GD3 oligosaccharides and other disialyl glycans containing natural and non-natural sialic acids

    PubMed Central

    Yu, Hai; Cheng, Jiansong; Ding, Li; Khedri, Zahra; Chen, Yi; Chin, Sharlene; Lau, Kam; Tiwari, Vinod Kumar; Chen, Xi

    2009-01-01

    In order to understand the biological importance of naturally occurring sialic acid variations on disialyl structures in nature, we developed an efficient two-step multi-enzyme approach for the synthesis of a series of GD3 ganglioside oligosaccharides and other disialyl glycans containing a terminal Siaα2–8Sia component with different natural and non-natural sialic acids. In the first step, α2–3- or α2–6-linked monosialylated oligosaccharides were obtained using a one-pot three-enzyme approach. These compounds were then used as acceptors for the α2–8-sialyltransferase activity of a recombinant truncated multi-functional Campylobacter jejuni sialyltransferase CstII mutant, CstIIΔ32I53S, to produce disialyl oligosaccharides. The α2–8-sialyltransferase activity of CstIIΔ32I53S has promiscuous donor substrate specificity and can tolerate various substitutions at C-5 or C-9 of the sialic acid in CMP-sialic acid, while its acceptor substrate specificity is relatively restricted. The terminal sialic acid residues in the acceptable monosialylated oligosaccharide acceptors are restricted to Neu5Ac, Neu5Gc, KDN, and some of their C-9 modified forms but not their C-5 derivatives. The disialyl oligosaccharides obtained are valuable probes for their biological studies. PMID:19947630

  12. Gangliosides in human, cow and goat milk, and their abilities as to neutralization of cholera toxin and botulinum type A neurotoxin.

    PubMed

    Iwamori, Masao; Takamizawa, Kotarou; Momoeda, Mikio; Iwamori, Yuriko; Taketani, Yuji

    2008-10-01

    To elucidate the potential of mammalian milk as to protection of infants from infections, we determined the ganglioside compositions of human, cow and goat milk in relation with cholera toxin and botulinum type A neurotoxin-receptors. Gangliosides accounted for 1 to 2 micromol of lipid-bound sialic acid (LSA) in 100 ml of milk, and GD3 comprised about 69% of LSA in all milk samples. Among the milk samples examined, goat milk was found to contain an amount of gangliosides belonging to the b-pathway representing 15.8% of the total LSA. Accordingly, botulinum neurotoxin bound to GT1b and GQ1b in goat milk, but not to any gangliosides in human or cow milk. On the other hand, GM1, the cholera toxin receptor, was found to be present in all milk samples at concentrations of 0.02% to 0.77% of the total LSA and to be maintained at a relatively constant level in human milk during the postpartum period. Gangliosides from 1 ml of pooled human milk exhibited the ability to attenuate the binding of cholera toxin (30 ng) to GM1 by 93%, and those from 500 microl of goat milk completely inhibited the binding of botulinum type A neurotoxin 1.5 microg to GT1b.

  13. Immunosuppressive activity of human neuroblastoma tumor gangliosides.

    PubMed

    Floutsis, G; Ulsh, L; Ladisch, S

    1989-01-15

    Gangliosides are shed in substantial amounts by some tumors, including human neuroblastoma, and these molecules modulate experimental tumor formation in vivo. We now demonstrate that neuroblastoma tumor gangliosides have potent immunoregulatory activity. Gangliosides of every one of 17 tumors studied were highly inhibitory for the normal in vitro human lymphoproliferative responses to the soluble antigen, tetanus toxoid; 30 nmol ganglioside/ml caused 43% to greater than 99% inhibition and the mean concentration causing 50% inhibition was only 17.3 nmol/ml. Furthermore, gangliosides isolated from clinically more aggressive tumors (Stage III or IV) were up to twice as immunosuppressive as those of the generally less aggressive tumors (Stage I or II) (p less than 0.05). Taken together with the lack of immunosuppressive activity of normal plasma gangliosides, the potent activity of neuroblastoma gangliosides supports the hypothesis that one mechanism by which these shed molecules may act to enhance tumor formation in vivo is through abrogation of the host cellular immune response at the site of tumor formation.

  14. Unique Ganglioside Recognition Strategies for Clostridial Neurotoxins

    SciTech Connect

    Benson, Marc A.; Fu, Zhuji; Kim, Jung-Ja P.; Baldwin, Michael R.

    2012-03-15

    Botulinum neurotoxins (BoNTs) and tetanus neurotoxin are the causative agents of the paralytic diseases botulism and tetanus, respectively. The potency of the clostridial neurotoxins (CNTs) relies primarily on their highly specific binding to nerve terminals and cleavage of SNARE proteins. Although individual CNTs utilize distinct proteins for entry, they share common ganglioside co-receptors. Here, we report the crystal structure of the BoNT/F receptor-binding domain in complex with the sugar moiety of ganglioside GD1a. GD1a binds in a shallow groove formed by the conserved peptide motif E ... H ... SXWY ... G, with additional stabilizing interactions provided by two arginine residues. Comparative analysis of BoNT/F with other CNTs revealed several differences in the interactions of each toxin with ganglioside. Notably, exchange of BoNT/F His-1241 with the corresponding lysine residue of BoNT/E resulted in increased affinity for GD1a and conferred the ability to bind ganglioside GM1a. Conversely, BoNT/E was not able to bind GM1a, demonstrating a discrete mechanism of ganglioside recognition. These findings provide a structural basis for ganglioside binding among the CNTs and show that individual toxins utilize unique ganglioside recognition strategies.

  15. Ganglioside Regulation of AMPA Receptor Trafficking

    PubMed Central

    Prendergast, Jillian; Umanah, George K.E.; Yoo, Seung-Wan; Lagerlöf, Olof; Motari, Mary G.; Cole, Robert N.; Huganir, Richard L.; Dawson, Ted M.; Dawson, Valina L.

    2014-01-01

    Gangliosides are major cell-surface determinants on all vertebrate neurons. Human congenital disorders of ganglioside biosynthesis invariably result in intellectual disability and are often associated with intractable seizures. To probe the mechanisms of ganglioside functions, affinity-captured ganglioside-binding proteins from rat cerebellar granule neurons were identified by quantitative proteomic mass spectrometry. Of the six proteins that bound selectively to the major brain ganglioside GT1b (GT1b:GM1 > 4; p < 10−4), three regulate neurotransmitter receptor trafficking: Thorase (ATPase family AAA domain-containing protein 1), soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (γ-SNAP), and the transmembrane protein Nicalin. Thorase facilitates endocytosis of GluR2 subunit-containing AMPA-type glutamate receptors (AMPARs) in an ATPase-dependent manner; its deletion in mice results in learning and memory deficits (J. Zhang et al., 2011b). GluR2-containing AMPARs did not bind GT1b, but bound specifically to another ganglioside, GM1. Addition of noncleavable ATP (ATPγS) significantly disrupted ganglioside binding, whereas it enhanced AMPAR association with Thorase, NSF, and Nicalin. Mutant mice lacking GT1b expressed markedly higher brain Thorase, whereas Thorase-null mice expressed higher GT1b. Treatment of cultured hippocampal neurons with sialidase, which cleaves GT1b (and other sialoglycans), resulted in a significant reduction in the size of surface GluR2 puncta. These data support a model in which GM1-bound GluR2-containing AMPARs are functionally segregated from GT1b-bound AMPAR-trafficking complexes. Release of ganglioside binding may enhance GluR2-containing AMPAR association with its trafficking complexes, increasing endocytosis. Disrupting ganglioside biosynthesis may result in reduced synaptic expression of GluR2-contianing AMPARs resulting in intellectual deficits and seizure susceptibility in mice and humans. PMID:25253868

  16. How Do Gangliosides Regulate RTKs Signaling?

    PubMed Central

    Julien, Sylvain; Bobowski, Marie; Steenackers, Agata; Le Bourhis, Xuefen; Delannoy, Philippe

    2013-01-01

    Gangliosides, the glycosphingolipids carrying one or several sialic acid residues, are located on the outer leaflet of the plasma membrane in glycolipid-enriched microdomains, where they interact with molecules of signal transduction pathways including receptors tyrosine kinases (RTKs). The role of gangliosides in the regulation of signal transduction has been reported in many cases and in a large number of cell types. In this review, we summarize the current knowledge on the biosynthesis of gangliosides and the mechanism by which they regulate RTKs signaling. PMID:24709879

  17. Monitoring Diabetic Nephropathy by Circulating Gangliosides.

    PubMed

    Ene, Corina Daniela; Penescu, Mircea; Anghel, Amalia; Neagu, Monica; Budu, Vlad; Nicolae, Ilinca

    2016-01-01

    Gangliosides are multifunctional molecules, abundantly expressed in renal cell membrane but also in sera of patients with renal disease. The aim of this study was to quantify the serum levels of sialic acid-ganglioside in patients diagnosed with diabetes for an eventual biomarker stratification of patients with renal complications. We included 35 diabetic patients without metabolic complications, 35 patients with diabetic nephropathy, 35 non-diabetic individuals. We found that sialic acid ganglioside serum level was significantly increased in patients with diabetic nephropathy compared to the level obtained in patients with uncomplicated diabetes and to non-diabetic controls. A statistically significant positive correlation was obtained between serum levels of sialic acid gangliosides, HbA1c, and serum creatinine in patients with diabetes without complications. Moreover positive correlation was found between sialic acid ganglioside and blood glucose, HbA1c, urea, creatinine, microalbuminuria in patients with diabetic nephropathy. We can conclude that serum sialic acid-gangliosides are statistically increased in diabetic nephropathy positively correlated with microalbuminuria. PMID:26359623

  18. Surface enhanced Raman scattering of amino acids assisted by gold nanoparticles and Gd(3+) ions.

    PubMed

    López-Neira, Juan Pablo; Galicia-Hernández, José Mario; Reyes-Coronado, Alejandro; Pérez, Elías; Castillo-Rivera, Francisco

    2015-05-01

    The surface enhanced raman scattering (SERS) signal from the l-tyrosine (tyr) molecule adsorbed on gold nanoparticles (Au-tyr) is compared with the SERS signal assisted by the presence of gadolinium ions (Gd(3+)) coordinated with the Au-tyr system. An enhancement factor of the SERS signal in the presence of Gd(3+) ions was ∼5 times higher than that produced by l-tyrosine adsorbed on gold nanoparticles. The enhancement of the SERS signal can be attributed to a corresponding increase in the local electric field due to the presence of Gd(3+) ions in the vicinity of a gold dimer configuration. This scenario was confirmed by solving numerically Maxwell equations, showing an increase of 1 order of magnitude in the local electric scattered field when the Gd(3+) ion is located in between a gold dimer compared with naked gold nanoparticles.

  19. Structural and magnetic properties of Gd3+ ion substituted magnesium ferrite nanopowders

    NASA Astrophysics Data System (ADS)

    Elkady, Ashraf S.; Hussein, Shaban I.; Rashad, Mohamed M.

    2015-07-01

    Nanocrystalline MgGdxFe2-xO4 powders (where x=0, 0.05, 0.1, 0.2, 0.25, 0.3) have been synthesized by the ethylene diamine tetraacetic acid (EDTA)-based sol-gel combustion method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer (VSM) were applied in order to study the effect of variation of Gd3+ ion substitution and its impact on crystal structure, crystallite size, lattice parameters, nanostructure and magnetic properties of the formed powders. XRD indicated that, after doping and calcination at 400 °C for 2 h, all samples have two spinel ferrite structures namely cubic and tetragonal phases, which are dependent on Gd3+ ion concentration. The cubic phase is found to increase with increasing the Gd3+ ion molar ratio up to 0.1, compared to pure MgFe2O4 and higher Gd3+ content samples. Indeed, with increasing Gd3+ ion, the crystallite size was almost unchanged whereas the lattice parameter was found to increase. FT-IR spectrum showed broadening of the ν2 band and the presence of another band in the range (465-470 cm-1) upon adding Gd3+ ion, which confirm the presence of Gd3+ ion in addition to Fe3+ ion at octahedral site. Besides, these bands were assigned to the formation of (Gd3+-O2-) complexes at B-sites. HRTEM images showed that the studied samples consist of nanocrystallites having average particle sizes around 9 nm for pure MgFe2O4 up to 27 and 42 nm for the Gd3+ ion substituted MgFe2O4 of molar ratio 0.05 and 0.30, respectively. An examination of the magnetic properties revealed an increase in saturation magnetization with increasing Gd concentration incorporation up to x=0.1, as a result of the change of cubic and tetragonal spinel ratio and lattice parameters. Meanwhile, the formed powders exhibited superparamagnetic characteristics. Therefore, such newly synthesized superparamagnetic nanoparticles, containing Gd3+ ion can be considered as a

  20. The immune response to disialoganglioside GD3 vaccination in normal dogs: a melanoma surface antigen vaccine.

    PubMed

    Milner, R J; Salute, M; Crawford, C; Abbot, J R; Farese, J

    2006-12-15

    As a result of its metastatic potential, canine malignant melanoma like its human counterpart like its human counter part, has a poor response to conventional treatment protocols. This prompted us to investigate the possibility of enhancing the immune response against the melanoma cell surface antigen, disialoganglioside GD3. Initially a flow cytometric study was designed in which the incidence of GD3 on the cell surface, recognized by the monoclonal antibody Mel-1 (R24), was established in canine melanoma cell lines. Results from the flow cytometry found GD3 to be highly expressed (94.2%) in six out of seven canine melanoma cell lines. Since it was thus potentially a good target, a study in which normal dogs were vaccinated intradermally with a vaccine containing GD3 plus adjuvants was designed. The adjuvant included CpG oligodeoxynucleotide (CpG-ODN) sequences and RIBI-adjuvant, which are known to target toll-like receptors (TLR) of the innate immune system. From a cohort of 10 dogs, 4 were vaccinated 3 times, at 4 weekly intervals with GD3 plus adjuvant, and 4 received only RIBI-adjuvant, and 2 phosphate buffered saline. Caliper measurements were collected to assess skin reaction at the vaccination site and sera assayed for IgM and IgG antibodies against GD3 and cell-mediated cytotoxicity against a melanoma cell line. Results from the study found significant differences (P<0.05) in the vaccine site reactions, IgM/IgG levels and cell-mediated cytotoxicity in the vaccinated versus unvaccinated dogs. The addition of CpG-ODN sequences and increasing GD3 concentration in the vaccine increased the inflammation response at the injection site. GD3 IgG and IgM antibodies in vaccinated dogs showed increasing titers over time and achieved significance at weeks 9 and 12, respectively. Cell-mediated cytotoxicity was only detected in peripheral blood mononuclear cells from vaccinated dogs. In conclusion, by combining the tumor antigen GD3 (a known weak self-antigen) and an

  1. Gangliosides, or sialic acid, antagonize ethanol intoxication

    SciTech Connect

    Klemm, W.R.; Boyles, R.; Matthew, J.; Cherian, L.

    1988-01-01

    Because ethanol elicits a dose-dependent hydrolysis of brain sialogangliosides, the authors tested the possibility that injected gangliosides might antagonize intoxicating doses of ethanol. Clear anti-intoxication effects were seen at 24 hr post-injection of mixed mouse-brain gangliosides at 125-130 mg/kg, but not at lower or higher doses. Sleep time was reduced on the order of 50%, and roto-rod agility was significantly enhanced. Sialic acid (SA) similarly antagonized ethanol; however, the precursor of SA, N-acetyl-D-mannosamine, as well as ceramide and asialoganglioside did not.

  2. Ganglioside-magnetosome complex formation enhances uptake of gangliosides by cells

    PubMed Central

    Guan, Feng; Li, Xiang; Guo, Jia; Yang, Ganglong; Li, Xiang

    2015-01-01

    Bacterial magnetosomes, because of their nano-scale size, have a large surface-to-volume ratio and are able to carry large quantities of bioactive substances such as enzymes, antibodies, and genes. Gangliosides, a family of sialic acid-containing glycosphingolipids, function as distinctive cell surface markers and as specific determinants in cellular recognition and cell-to-cell communication. Exogenously added gangliosides are often used to study biological functions, transport mechanisms, and metabolism of their endogenous counterparts. Absorption of gangliosides into cells is typically limited by their tendency to aggregate into micelles in aqueous media. We describe here a simple strategy to remove proteins from the magnetosome membrane by sodium dodecyl sulfate treatment, and efficiently immobilize a ganglioside (GM1 or GM3) on the magnetosome by mild ultrasonic treatment. The maximum of 11.7±1.2 µg GM1 and 11.6±1.5 μg GM3 was loaded onto 1 mg magnetosome, respectively. Complexes of ganglioside-magnetosomes stored at 4°C for certain days presented the consistent stability. The use of GM1-magnetosome complex resulted in the greatest enhancement of ganglioside incorporation by cells. GM3-magnetosome complex significantly inhibited EGF-induced phosphorylation of the epidermal growth factor receptor. Both of these effects were further enhanced by the presence of a magnetic field. PMID:26609230

  3. Ganglioside/glycosphingolipid turnover: new concepts.

    PubMed

    Tettamanti, G

    2004-01-01

    In this review focus is given to the metabolic turnover of gangliosides/glycosphingolipids. The metabolism and accompanying intracellular trafficking of gangliosides/glycosphingolipids is illustrated with particular attention to the following events: (a) the de novo biosynthesis in the endoplasmic reticulum and Golgi apparatus, followed by vesicular sorting to the plasma membrane; (b) the enzyme-assisted chemical modifications occurring at the plasma membrane level; (c) the internalization via endocytosis and recycling to the plasma membrane; (d) the direct glycosylations taking place after sorting from endosomes to the Golgi apparatus; (e) the degradation at the late endosomal/lysosomal level with formation of fragments of sugar (glucose, galactose, hexosamine, sialic acid) and lipid (ceramide, sphingosine, fatty acid) nature; (f) the metabolic recycling of these fragments for biosynthetic purposes (salvage pathways); and (g) further degradation of fragments to waste products. Noteworthy, the correct course of ganglioside/glycosphingolipid metabolism requires the presence of the vimentin intracellular filament net work, likely to assist intracellular transport of sphingoid molecules. ut of the above events those that can be quantitatively evaluated with acceptable reliability are the processes of de novo biosynthesis, metabolic salvage and direct glycosylation. Depending on the cultured cells employed, the percentage of distribution of de novo biosynthesis, salvage pathways, and direct glycosylation, over total metabolism were reported to be: 35% (range: 10-90%) for de novo biosynthesis, 7% (range: 5-10%) for direct glycosylation, and 58% (range: 10-90%) for salvage pathways. The attempts made to calculate the half-life of overall ganglioside turnover provided data of unsure reliability, especially because in many studies salvage pathways were not taken into consideration. The values of half-life range from 2 to 6.5 h to 3 days depending on the cells used

  4. Electron Spin resonance of Gd3+ in three dimensional topological insulator Bi2Se3

    NASA Astrophysics Data System (ADS)

    Garitezi, T. M.; Lesseux, G. G.; Jesus, C. B. R.; Grant, T.; Fisk, Z.; Urbano, R. R.; Rettori, C.; Pagliuso, P. G.

    2015-03-01

    Bi2Se3 has been claimed to be a three dimensional topological insulator (TI) with topologically protected metallic surface states with exotic properties. We have performed electron spin resonance (ESR) measurements on Gd3+ doped (x ≈ 0.01) Bi2Se3 single crystal grown from stoichiometric melt. For the studied crystals, our preliminary results revealed a partly resolved Gd3+ fine structure spectrum with Dysonian (metallic character) lines. At room temperature, the central line has a g ≈ 1.98, a linewidth ΔH ≈ 95 G and the spectra have a overall splitting of roughly 1300 Oe. As the temperature is decreased, the Gd3+ ESR ΔH of the central line presents a very small Korringa-like behavior b = ΔH/ΔT ≈ 0.013 Oe/K and nearly T-independent g-value. However, for T lesssim 40 K, ΔH shows a stronger narrowing effect evolving to Korringa-like behavior (b ≈ 0.15 Oe/K) for T lesssim 30 K. Concomitantly with the change in ΔH behavior, the Gd3+ central line g value starts to decrease reaching a value of 1.976 at T = 4.2 K. The ESR results are discussed in terms of possible effects of protected topological surface states enlightened by complementary data from macroscopic measurements.

  5. Overview of GD2 and GD3 with Caisson of Dry Dock ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Overview of GD-2 and GD-3 with Caisson of Dry Dock No. 2 in center - U.S. Naval Base, Pearl Harbor, Pier & Quay Walls, Entrance to Dry Dock No. 2 & Repair Wharfs, east & west sides of Dry Dock No. 2 & west side of Dry Dock No. 3, Pearl City, Honolulu County, HI

  6. Pier GD3, view of top of deck and fender edge, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Pier GD-3, view of top of deck and fender edge, GD-4 beyond, taken from Dry Dock No. 2 Caisson - U.S. Naval Base, Pearl Harbor, Pier & Quay Walls, Entrance to Dry Dock No. 2 & Repair Wharfs, east & west sides of Dry Dock No. 2 & west side of Dry Dock No. 3, Pearl City, Honolulu County, HI

  7. GD4 with GD3 at oblique view on left U.S. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GD-4 with GD-3 at oblique view on left - U.S. Naval Base, Pearl Harbor, Pier & Quay Walls, Entrance to Dry Dock No. 2 & Repair Wharfs, east & west sides of Dry Dock No. 2 & west side of Dry Dock No. 3, Pearl City, Honolulu County, HI

  8. Pier GD3, oblique view taken from Pier GD2, Caisson of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Pier GD-3, oblique view taken from Pier GD-2, Caisson of Dry Dock No. 2 to left - U.S. Naval Base, Pearl Harbor, Pier & Quay Walls, Entrance to Dry Dock No. 2 & Repair Wharfs, east & west sides of Dry Dock No. 2 & west side of Dry Dock No. 3, Pearl City, Honolulu County, HI

  9. Phase formation and UV luminescence of Gd3+ doped perovskite-type YScO3

    NASA Astrophysics Data System (ADS)

    Shimizu, Yuhei; Ueda, Kazushige

    2016-10-01

    Synthesis of pure and Gd3+doped perovskite-type YScO3 was attempted by a polymerized complex (PC) method and solid state reaction (SSR) method. Crystalline phases and UV luminescence of samples were examined with varying heating temperatures. The perovskite-type single phase was not simply formed in the SSR method, as reported in some literatures, and two cubic C-type phases of starting oxide materials remained forming slightly mixed solid solutions. UV luminescence of Gd3+ doped samples increased with an increase in heating temperatures and volume of the perovskite-type phase. In contrast, a non-crystalline precursor was crystallized to a single C-type phase at 800 °C in the PC method forming a completely mixed solid solution. Then, the phase of perovskite-type YScO3 formed at 1200 °C and its single phase was obtained at 1400 °C. It was revealed that high homogeneousness of cations was essential to generate the single perovskite-phase of YScO3. Because Gd3+ ions were also dissolved into the single C-type phase in Gd3+ doped samples, intense UV luminescence was observed above 800 °C in both C-type phase and perovskite-type phase.

  10. Gold nanoparticles functionalised with fast water exchanging Gd3+ chelates: linker effects on the relaxivity.

    PubMed

    Ferreira, Miguel F; Gonçalves, Janaina; Mousavi, Bibimaryam; Prata, Maria I M; Rodrigues, Sérgio P J; Calle, Daniel; López-Larrubia, Pilar; Cerdan, Sebastian; Rodrigues, Tiago B; Ferreira, Paula M; Helm, Lothar; Martins, José A; Geraldes, Carlos F G C

    2015-03-01

    The relaxivity displayed by Gd(3+) chelates immobilized onto gold nanoparticles is the result of the complex interplay between the nanoparticle size, the water exchange rate and the chelate structure. In this work we study the effect of the length of ω-thioalkyl linkers, anchoring fast water exchanging Gd(3+) chelates onto gold nanoparticles, on the relaxivity of the immobilized chelates. Gold nanoparticles functionalized with Gd(3+) chelates of mercaptoundecanoyl and lipoyl amide conjugates of the DO3A-N-(α-amino)propionate chelator were prepared and studied as potential CA for MRI. High relaxivities per chelate, of the order of magnitude 28-38 mM(-1) s(-1) (30 MHz, 25 °C), were attained thanks to simultaneous optimization of the rotational correlation time and of the water exchange rate. Fast local rotational motions of the immobilized chelates around connecting linkers (internal flexibility) still limit the attainable relaxivity. The degree of internal flexibility of the immobilized chelates seems not to be correlated with the length of the connecting linkers. Biodistribution and MRI studies in mice suggest that the in vivo behavior of the gold nanoparticles was determined mainly by size. Small nanoparticles (HD = 3.9 nm) undergo fast renal clearance and avoidance of the RES organs while larger nanoparticles (HD = 4.8 nm) undergo predominantly hepatobiliary excretion. High relaxivities, allied to chelate and nanoparticle stability and fast renal clearance in vivo suggest that functionalized gold nanoparticles hold great potential for further investigation as MRI contrast agents. This study contributes to a better understanding of the effect of linker length on the relaxivity of gold nanoparticles functionalized with Gd(3+) complexes. It is a relevant contribution towards "design rules" for nanostructures functionalized with Gd(3+) chelates as Contrast Agents for MRI and multimodal imaging.

  11. The role of gangliosides in neurodevelopment.

    PubMed

    Palmano, Kate; Rowan, Angela; Guillermo, Rozey; Guan, Jian; McJarrow, Paul

    2015-05-22

    Gangliosides are important components of neuronal cell membranes and it is widely accepted that they play a critical role in neuronal and brain development. They are functionally involved in neurotransmission and are thought to support the formation and stabilization of functional synapses and neural circuits required as the structural basis of memory and learning. Available evidence, as reviewed herein, suggests that dietary gangliosides may impact positively on cognitive functions, particularly in the early postnatal period when the brain is still growing. Further, new evidence suggests that the mechanism of action may be through an effect on the neuroplasticity of the brain, mediated through enhanced synaptic plasticity in the hippocampus and nigro-striatal dopaminergic pathway.

  12. The Role of Gangliosides in Neurodevelopment

    PubMed Central

    Palmano, Kate; Rowan, Angela; Guillermo, Rozey; Guan, Jian; Mc Jarrow, Paul

    2015-01-01

    Gangliosides are important components of neuronal cell membranes and it is widely accepted that they play a critical role in neuronal and brain development. They are functionally involved in neurotransmission and are thought to support the formation and stabilization of functional synapses and neural circuits required as the structural basis of memory and learning. Available evidence, as reviewed herein, suggests that dietary gangliosides may impact positively on cognitive functions, particularly in the early postnatal period when the brain is still growing. Further, new evidence suggests that the mechanism of action may be through an effect on the neuroplasticity of the brain, mediated through enhanced synaptic plasticity in the hippocampus and nigro-striatal dopaminergic pathway. PMID:26007338

  13. Anchored and soluble gangliosides contribute to myelosupportivity of stromal cells

    SciTech Connect

    Ziulkoski, Ana L.; Santos, Aline X.S. dos; Andrade, Claudia M.B.; Trindade, Vera M.T.; Daniotti, Jose Luis; Borojevic, Radovan; Guma, Fatima C.R.

    2009-10-09

    Stroma-mediated myelopoiesis depends upon growth factors and an appropriate intercellular microenvironment. Previous studies have demonstrated that gangliosides, produced by hepatic stromal cell types, are required for optimal myelosupportive function. Here, we compared the mielossuportive functions of a bone marrow stroma (S17) and skin fibroblasts (SF) regarding their ganglioside pattern of synthesis and shedding. The survival and proliferation of a myeloid precursor cell (FDC-P1) were used as reporter. Although the ganglioside synthesis of the two stromal cells was similar, their relative content and shedding were distinct. The ganglioside requirement for mielossuportive function was confirmed by the decreased proliferation of FDC-P1 cells in ganglioside synthesis-inhibited cultures and in presence of an antibody to GM3 ganglioside. The distinct mielossuportive activities of the S17 and SF stromata may be related to differences on plasma membrane ganglioside concentrations or to differences on the gangliosides shed and their subsequent uptake by myeloid cells, specially, GM3 ganglioside.

  14. Gangliosides have a functional role during rotavirus cell entry.

    PubMed

    Martínez, Miguel Angel; López, Susana; Arias, Carlos F; Isa, Pavel

    2013-01-01

    Cell entry of rotaviruses is a complex process, which involves sequential interactions with several cell surface molecules. Among the molecules implicated are gangliosides, glycosphingolipids with one or more sialic acid (SA) residues. The role of gangliosides in rotavirus cell entry was studied by silencing the expression of two key enzymes involved in their biosynthesis--the UDP-glucose:ceramide glucosyltransferase (UGCG), which transfers a glucose molecule to ceramide to produce glucosylceramide GlcCer, and the lactosyl ceramide-α-2,3-sialyl transferase 5 (GM3-s), which adds the first SA to lactoceramide-producing ganglioside GM3. Silencing the expression of both enzymes resulted in decreased ganglioside levels (as judged by GM1a detection). Four rotavirus strains tested (human Wa, simian RRV, porcine TFR-41, and bovine UK) showed a decreased infectivity in cells with impaired ganglioside synthesis; however, their replication after bypassing the entry step was not affected, confirming the importance of gangliosides for cell entry of the viruses. Interestingly, viral binding to the cell surface was not affected in cells with inhibited ganglioside synthesis, but the infectivity of all strains tested was inhibited by preincubation of gangliosides with virus prior to infection. These data suggest that rotaviruses can attach to cell surface in the absence of gangliosides but require them for productive cell entry, confirming their functional role during rotavirus cell entry.

  15. Postnatal dietary supplementation with either gangliosides or choline: effects on spatial short-term memory in artificially-reared rats.

    PubMed

    Wainwright, Patricia E; Lomanowska, Anna M; McCutcheon, Dawn; Park, Eek J; Clandinin, M Thomas; Ramanujam, Kalathur S

    2007-01-01

    This study addressed the hypothesis that dietary supplementation with either gangliosides or choline during the brain growth spurt would enhance short-term spatial memory. Male Long-Evans rats were reared artificially from postnatal days (PD) 5-18 and were fed diets containing either (i) choline chloride 1250 mg/l (CHL), (ii) choline chloride 250 mg/l and GD3 24 mg/l (GNG) or (iii) choline chloride 250 mg/l (STD). A fourth group (SCK) was reared normally. Rats were weaned onto AIN 93G diet and on PD 35 were trained on a cued delayed- matching-to-place version of the Morris water maze. All groups learned to swim to the beacon that indicated the platform position on the first trial; similarly, on the second un-cued trial, the distance swam to reach the platform decreased to the same extent in all groups over the five days of training. The groups also responded in the same way to an increase in delay between the first and second trial from 1 min to 1 h, showing an increase in the distance swam, accompanied by a decrease in the number of direct swims to the platform. Thus, all rats were equally proficient at using spatial short-term memory, regardless of the choline or ganglioside content of the preweaning diet.

  16. Structural aspects of ganglioside-containing membranes.

    PubMed

    Cantu', Laura; Corti, Mario; Brocca, Paola; Del Favero, Elena

    2009-01-01

    The demand for understanding the physical role of gangliosides in membranes is pressing, due to the high number of diverse and crucial biological functions in which they are involved, needing a unifying thread. To this purpose, model systems including gangliosides have been subject of extensive structural studies. Although showing different levels of complication, all models share the need for simplicity, in order to allow for physico-chemical clarity, so they keep far from the extreme complexity of the true biological systems. Nonetheless, as widely agreed, they provide a basic hint on the structural contribution specific molecules can pay to the complex aggregate. This topic we address in the present review. Gangliosides are likely to play their physical role through metamorphism, cooperativity and demixing, that is, they tend to segregate and identify regions where they can dictate and modulate the geometry and the topology of the structure, and its mechanical properties. Strong three-dimensional organisation and cooperativity are exploited to scale up the local arrangement hierarchically from the nano- to the mesoscale, influencing the overall morphology of the structure. PMID:19063860

  17. Pure white-light and colour-tuning of Eu(3+)-Gd(3+)-containing metallopolymer.

    PubMed

    Zhang, Zhao; He, Ya-Ni; Liu, Lin; Lü, Xing-Qiang; Zhu, Xun-Jin; Wong, Wai-Kwok; Pan, Mei; Su, Cheng-Yong

    2016-03-01

    Direct white-light (CIE coordinate of x = 0.333, y = 0.335, CCT of 5455 K and CRI of 82) with a high luminous efficiency (18.4%) was achieved in the first example of Eu(3+)-Gd(3+)-containing metallopolymer Poly(2-co-NVK-co-4), which also showed tunable purplish-blue to white to yellow-green photoluminescence. PMID:26864261

  18. Impact of Gd3+ doping and glassing solvent deuteration on 13C DNP at 5 Tesla

    NASA Astrophysics Data System (ADS)

    Kiswandhi, Andhika; Lama, Bimala; Niedbalski, Peter; Goderya, Mudrekh; Long, Joanna; Lumata, Lloyd

    Dynamic nuclear polarization (DNP) is a technique which can be used to amplify signals in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) by several thousand-fold. The most commonly available DNP system typically operates at the W-band field or 3.35 T, at which it has been shown that 13C NMR signal can be enhanced by deuteration and Gd3+ doping. In this work, we have investigated the applicability of these procedures at 5 T. Our results indicate that the deuteration of the glassing matrix still yields an enhancement of 13C DNP when 4-oxo-TEMPO free radical is used. The effect is attributed to the lower heat load of the deuterons compared to protons. An addition of a trace amount of Gd3+ gives a modest enhancement of the signal when trityl OX063 is used, albeit with a less pronounced relative enhancement compared to the results obtained at 3.35 T. The results suggest that the enhancement obtained via Gd3+ doping may become saturated at higher field. These results will be discussed using a thermodynamic model of DNP. This work is supported by US Dept of Defense Award No. W81XWH-14-1-0048 and Robert A. Welch Foundation Grant No. AT-1877.

  19. Gangliosides in the Nervous System: Biosynthesis and Degradation

    NASA Astrophysics Data System (ADS)

    Yu, Robert K.; Ariga, Toshio; Yanagisawa, Makoto; Zeng, Guichao

    Gangliosides, abundant in the nervous system, are known to play crucial modulatory roles in cellular recognition, interaction, adhesion, and signal transduction, particularly during early developmental stages. The expression of gangliosides in the nervous system is developmentally regulated and is closely related to the differentiation state of the cell. Ganglioside biosynthesis occurs in intracellular organelles, from which gangliosides are transported to the plasma membrane. During brain development, the ganglioside composition of the nervous system undergoes remarkable changes and is strictly regulated by the activities of glycosyltransferases, which can occur at different levels of control, including glycosyltransferase gene transcription and posttranslational modification. Genes for glycosyltransferase involved in ganglioside biosynthesis have been cloned and classified into families of glycosyltransferases based on their amino acid sequence similarities. The donor and acceptor substrate specificities are determined by enzymatic analysis of the glycosyltransferase gene products. Cell-type specific regulation of these genes has also been studied. Gangliosides are degraded by lysosomal exoglycosidases. The action of these enzymes occurs frequently in cooperation with activator proteins. Several human diseases are caused by defects of degradative enzymes, resulting in massive accumulation of certain glycolipids, including gangliosides in the lysosomal compartment and other organelles in the brain and visceral organs. Some of the representative lysosomal storage diseases (LSDs) caused by the accumulation of lipids in late endosomes and lysosomes will be discussed.

  20. Tuning the selectivity of Gd3N cluster endohedral metallofullerene reactions with Lewis acids.

    PubMed

    Stevenson, Steven; Rottinger, Khristina A; Fahim, Muska; Field, Jessica S; Martin, Benjamin R; Arvola, Kristine D

    2014-12-15

    We demonstrate the manipulation of the Lewis acid strength to selectively fractionate different types of Gd3N metallofullerenes that are present in complex mixtures. Carbon disulfide is used for all Lewis acid studies. CaCl2 exhibits the lowest reactivity but the highest selectivity by precipitating only those gadolinium metallofullerenes with the lowest first oxidation potentials. ZnCl2 selectively complexes Gd3N@C88 during the first 4 h of reaction. Reaction with ZnCl2 for an additional 7 days permits a selective precipitation of Gd3N@C84 as the dominant endohedral isolated. A third fraction is the filtrate, which possesses Gd3N@C86 and Gd3N@C80 as the two dominant metallofullerenes. The order of increasing reactivity and decreasing selectivity (left to right) is as follows: CaCl2 < ZnCl2 < NiCl2 < MgCl2 < MnCl2 < CuCl2 < WCl4 ≪ WCl6 < ZrCl4 < AlCl3 < FeCl3. As a group, CaCl2, ZnCl2, and NiCl2 are the weakest Lewis acids and have the highest selectivity because of their very low precipitation onsets, which are below +0.19 V (i.e., endohedrals with first oxidation potentials below +0.19 V are precipitated). For CaCl2, the precipitation threshold is estimated at a remarkably low value of +0.06 V. Because most endohedrals possess first oxidation potentials significantly higher than +0.06 V, CaCl2 is especially useful in its ability to precipitate only a select group of gadolinium metallofullerenes. The Lewis acids of intermediate reactivity (i.e., precipitation onsets estimated between +0.19 and +0.4 V) are MgCl2, MnCl2, CuCl2, and WCl4. The strongest Lewis acids (WCl6, ZrCl4, AlCl3, and FeCl3) are the least selective and tend to precipitate the entire family of gadolinium metallofullerenes. Tuning the Lewis acid for a specific type of endohedral should be useful in a nonchromatographic purification method. The ability to control which metallofullerenes are permitted to precipitate and which endohedrals would remain in solution is a key outcome of this work.

  1. Expression of GD2 ganglioside by untreated primary human neuroblastomas.

    PubMed

    Wu, Z L; Schwartz, E; Seeger, R; Ladisch, S

    1986-01-01

    Primary neuroblastomas obtained before therapy from 36 patients were studied to determine the frequency of tumors expressing a specific glycosphingolipid, GD2 ganglioside. Total tissue gangliosides were purified by a new partition method, quantitated, and analyzed by high-performance thin-layer chromatography. All 36 neuroblastoma tumors, representing all clinical stages, contained GD2 ganglioside. The mean relative and absolute concentrations of GD2 were substantial (12% of the total tissue gangliosides and 50 nmol/g of tissue) and were independent of the clinical stage of the tumor. In contrast, 6 samples of related but more differentiated tumors (ganglioneuroblastoma and ganglioneuroma) had little or no detectable GD2 (less than or equal to 1.5% of total gangliosides and less than or equal to 4 nmol/g of tissue). These results suggest that GD2 is a sensitive marker for neuroblastoma tissue and may be an excellent target antigen for immunotherapy of this tumor.

  2. Expansion of natural killer cells in mice transgenic for IgM antibody to ganglioside GD2: demonstration of prolonged survival after challenge with syngeneic tumor cells.

    PubMed

    Kawashima, Ikuo; Yoshida, Yukiko; Taya, Chouji; Shitara, Hiroshi; Yonekawa, Hiromichi; Karasuyama, Hajime; Tada, Nobuhiko; Furukawa, Koichi; Tai, Tadashi

    2003-08-01

    IgM antibodies to gangliosides, sialic acid-containing glycosphingolipids, have been shown to mediate anti-tumor effects in cancer patients with melanoma and neuroblastoma and to correlate with survival. Mechanisms by which the antibodies induce tumor suppression, however, have not been systematically studied. To investigate this point, we produced and characterized C57BL/6 mice transgenic for IgM antibody to ganglioside GD2. The transgenic (TG) mice showed high IgM, but not IgG antibody titers against GD2 in their sera. No significant clinical symptoms were observed. When EL4 cells, syngeneic T lymphoma that express ganglioside GD2, were injected into TG mice, prolonged survival was observed. Complement-dependent cytotoxicity (CDC) of EL4 cells was mediated with TG mice sera. Neither antibody-dependent cellular cytotoxicity with their sera nor cytotoxic T lymphocyte activity to EL4 cells was shown in TG mice. Spleen lymphocytes from TG mice had increased numbers of natural killer (NK) cells, but not T cells, B cells, or macrophages compared with wild-type mice. Depletion of NK cells with anti-asialo GM1 rabbit serum reduced or abrogated the observed anti-tumor effects, suggesting that NK cells play a major role in tumor eradication or suppression. NK cell activity in TG mice was much higher than wild-type mice. Moreover, TG mice showed prolonged survival after injection with syngeneic B16 melanoma cells, which express GM3, but not GD2 or GD3. Taking these results together, our studies demonstrate that the TG mice have significant anti-tumor characteristics, probably due to CDC and NK cell expansion and activation with anti-ganglioside GD2 antibody.

  3. [Luminescence properties and energy transfer between Ce3+ and Gd3+ ions in KAlF4:Ce, Gd].

    PubMed

    Wu, G; Chen, R; Zhang, Q

    2000-04-01

    The matrix KAlF4 was prepared with a reaction of mixtures of solution K2CO3 upon certain solution of Al(OH)3 plus HF (40%), dehydrating at 100 degrees C and annealing for 48 h at 450 degrees C. A series of phosphors KAlF4:Ce, Gd were synthesized by a solid reaction method. Their excitation and emission spectra were determined. It was observed that Ce3+ could sensitize Gd3+ in KAlF4 effectively, so as to enhance the emission of Gd3+ significantly. But emission intensity of Gd3 + 6 P1/2-->8S7/2 decreased with the concentration of Gd3+ increased when the concentration of Ce3+ was constant.

  4. Investigation of Gd3N@C2n (40 n 44) family by Raman and inelastic electron tunneling spectroscopy

    SciTech Connect

    Burke, Brian; Chan, Jack; Williams, Keith A; Ge, Jiechao; Shu, Chunying; Fu, Wujun; Dorn, Harry C; Kushmerick, James G; Puretzky, Alexander A; Geohegan, David B

    2010-01-01

    The structure and vibrational spectrum of Gd3N@C80 is studied through Raman and inelastic electron tunneling spectroscopy as well as density-functional theory and universal force eld calculations. Hindered rotations, shown by both theory and experiment, indicate the formation of a Gd3N-C80 bond which reduces the ideal icosahedral symmetry of the C80 cage. The vibrational modes involving the movement of the encapsulated species are a ngerprint of the interaction between the fullerene cage and the core complex. We present Raman data for the Gd3N@C2n 40 n 44 family as well as Y3N@C80, Lu3N@C80, and Y3N@C88 for comparison. Conductance measurements have been performed on Gd3N@C80 and reveal a Kondo effect similar to that observed in C60.

  5. Recombination luminescence of CaSO4:Tb3+ and CaSO4:Gd3+phosphors

    NASA Astrophysics Data System (ADS)

    Kudryavtseva, Irina; Lushchik, Aleksandr; Maaroos, Aarne; Azmaganbetova, Zhannur; Nurakhmetov, Turlybek; Salikhoja, Zhussupbek

    2012-08-01

    A comparative study of the excitation of luminescence by VUV radiation as well as of thermally and photostimulated luminescence has been carried out for CaSO4:Tb3+ and CaSO4:Gd3+ phosphors, where Na+ or F- ions are used for charge compensation. The distinction in hole processes for the phosphors with Na+ or F- compensators is determined by the differing thermal stability of the holes localized at/near Tb3+Na+ and Gd3+Na+ (up to 100-160 K) or at/near Tb3+F- V Ca and Gd3+F- V Ca centers involving also a cation vacancy (up to 400-550 K). Tunnel luminescence in the pairs of localized electrons and holes nearby Tb3+ or Gd3+ has been detected. The mechanisms of electron-hole, hole-electron and tunnel recombination luminescence as well as a subsequent released energy transfer to RE3+ ions are considered.

  6. Autoantibodies against ganglioside GM3 are associated with narcolepsy-cataplexy developing after Pandemrix vaccination against 2009 pandemic H1N1 type influenza virus.

    PubMed

    Saariaho, Anna-Helena; Vuorela, Arja; Freitag, Tobias L; Pizza, Fabio; Plazzi, Giuseppe; Partinen, Markku; Vaarala, Outi; Meri, Seppo

    2015-09-01

    Following the mass vaccinations against pandemic influenza A/H1N1 virus in 2009, a sudden increase in juvenile onset narcolepsy with cataplexy (NC) was detected in several European countries where AS03-adjuvanted Pandemrix vaccine had been used. NC is a chronic neurological disorder characterized by excessive daytime sleepiness and cataplexy. In human NC, the hypocretin-producing neurons in the hypothalamus or the hypocretin signaling pathway are destroyed by an autoimmune reaction. Both genetic (e.g. HLA-DQB1*0602) and environmental risk factors (e.g. Pandemrix) contribute to the disease development, but the underlying and the mediating immunological mechanisms are largely unknown. Influenza virus hemagglutinin is known to bind gangliosides, which serve as host cell virus receptors. Anti-ganglioside antibodies have previously been linked to various neurological disorders, like the Guillain-Barré syndrome which may develop after infection or vaccination. Because of these links we screened sera of NC patients and controls for IgG anti-ganglioside antibodies against 11 human brain gangliosides (GM1, GM2, GM3, GM4, GD1a, GD1b, GD2, GD3, GT1a, GT1b, GQ1b) and a sulfatide by using a line blot assay. Samples from 173 children and adolescents were analyzed: 48 with Pandemrix-associated NC, 20 with NC without Pandemrix association, 57 Pandemrix-vaccinated and 48 unvaccinated healthy children. We found that patients with Pandemrix-associated NC had more frequently (14.6%) anti-GM3 antibodies than vaccinated healthy controls (3.5%) (P = 0.047). Anti-GM3 antibodies were significantly associated with HLA-DQB1*0602 (P = 0.016) both in vaccinated NC patients and controls. In general, anti-ganglioside antibodies were more frequent in vaccinated (18.1%) than in unvaccinated (7.3%) individuals (P = 0.035). Our data suggest that autoimmunity against GM3 is a feature of Pandemrix-associated NC and that autoantibodies against gangliosides were induced by Pandemrix vaccination.

  7. Gd(3+) Spin Labels Report the Conformation and Solvent Accessibility of Solution and Vesicle-Bound Melittin.

    PubMed

    Manukovsky, Nurit; Frydman, Veronica; Goldfarb, Daniella

    2015-10-29

    Although Gd(3+)-based spin labels have been shown to be an alternative to nitroxides for double electron-electron resonance (DEER) distance measurements at high fields, their ability to provide solvent accessibility information, as nitroxides do, has not been explored. In addition, the effect of the label type on the measured distance distribution has not been sufficiently characterized. In this work, we extended the applicability of Gd(3+) spin labels to solvent accessibility measurements on a peptide in model membranes, namely, large unilamellar vesicles (LUVs) using W-band (2)H Mims electron-nuclear double resonance (ENDOR) and electron spin echo envelope modulation (ESEEM) techniques and Gd(3+)-ADO3A-labeled melittin. In addition, we carried out Gd(3+)-Gd(3+) DEER distance measurements to probe the peptide conformation in solution and when bound to LUVs. A comparison with earlier results reported for the same system with nitroxide labels shows that, although in both cases the peptide binds parallel to the membrane surface, the Gd(3+)-ADO3A label tends to protrude from the membrane into the solvent, whereas the nitroxide does the opposite. This can be explained on the basis of the hydrophilicity of the Gd(3+)-ADO3A labels in contrast with the hydrophobicity of nitroxides. The distance distributions obtained from different labels are accordingly different, with the Gd(3+)-ADO3A yielding consistently broader distributions. These discrepancies are most pronounced when the peptide termini are labeled, which implies that such labeling positions may be inadvisible. PMID:26001213

  8. Zero field splitting fluctuations induced phase relaxation of Gd3+ in frozen solutions at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Raitsimring, A.; Dalaloyan, A.; Collauto, A.; Feintuch, A.; Meade, T.; Goldfarb, D.

    2014-11-01

    Distance measurements using double electron-electron resonance (DEER) and Gd3+ chelates for spin labels (GdSL) have been shown to be an attractive alternative to nitroxide spin labels at W-band (95 GHz). The maximal distance that can be accessed by DEER measurements and the sensitivity of such measurements strongly depends on the phase relaxation of Gd3+ chelates in frozen, glassy solutions. In this work, we explore the phase relaxation of Gd3+-DOTA as a representative of GdSL in temperature and concentration ranges typically used for W-band DEER measurements. We observed that in addition to the usual mechanisms of phase relaxation known for nitroxide based spin labels, GdSL are subjected to an additional phase relaxation mechanism that features an increase in the relaxation rate from the center to the periphery of the EPR spectrum. Since the EPR spectrum of GdSL is the sum of subspectra of the individual EPR transitions, we attribute this field dependence to transition dependent phase relaxation. Using simulations of the EPR spectra and its decomposition into the individual transition subspectra, we isolated the phase relaxation of each transition and found that its rate increases with |ms|. We suggest that this mechanism is due to transient zero field splitting (tZFS), where its magnitude and correlation time are scaled down and distributed as compared with similar situations in liquids. This tZFS induced phase relaxation mechanism becomes dominant (or at least significant) when all other well-known phase relaxation mechanisms, such as spectral diffusion caused by nuclear spin diffusion, instantaneous and electron spin spectral diffusion, are significantly suppressed by matrix deuteration and low concentration, and when the temperature is sufficiently low to disable spin lattice interaction as a source of phase relaxation.

  9. Zero field splitting fluctuations induced phase relaxation of Gd3+ in frozen solutions at cryogenic temperatures.

    PubMed

    Raitsimring, A; Dalaloyan, A; Collauto, A; Feintuch, A; Meade, T; Goldfarb, D

    2014-11-01

    Distance measurements using double electron-electron resonance (DEER) and Gd(3+) chelates for spin labels (GdSL) have been shown to be an attractive alternative to nitroxide spin labels at W-band (95GHz). The maximal distance that can be accessed by DEER measurements and the sensitivity of such measurements strongly depends on the phase relaxation of Gd(3+) chelates in frozen, glassy solutions. In this work, we explore the phase relaxation of Gd(3+)-DOTA as a representative of GdSL in temperature and concentration ranges typically used for W-band DEER measurements. We observed that in addition to the usual mechanisms of phase relaxation known for nitroxide based spin labels, GdSL are subjected to an additional phase relaxation mechanism that features an increase in the relaxation rate from the center to the periphery of the EPR spectrum. Since the EPR spectrum of GdSL is the sum of subspectra of the individual EPR transitions, we attribute this field dependence to transition dependent phase relaxation. Using simulations of the EPR spectra and its decomposition into the individual transition subspectra, we isolated the phase relaxation of each transition and found that its rate increases with |ms|. We suggest that this mechanism is due to transient zero field splitting (tZFS), where its magnitude and correlation time are scaled down and distributed as compared with similar situations in liquids. This tZFS induced phase relaxation mechanism becomes dominant (or at least significant) when all other well-known phase relaxation mechanisms, such as spectral diffusion caused by nuclear spin diffusion, instantaneous and electron spin spectral diffusion, are significantly suppressed by matrix deuteration and low concentration, and when the temperature is sufficiently low to disable spin lattice interaction as a source of phase relaxation. PMID:25442776

  10. EPR of Gd3+ ion in mixed CeO2-Y2O3 nanocrystals

    NASA Astrophysics Data System (ADS)

    Aminov, L. K.; Kurkin, I. N.; Rakhmatullin, R. M.; Böttcher, R.; Pöppl, A.; Sen, S.

    2009-11-01

    This paper reports on the results of EPR studies of mixed CeO2-Y2O3 crystals (including nanosized crystals) doped by gadolinium ions. It is revealed that the width of the line corresponding to the allowed transition 1/2 ↔ -1/2 between the Kramers-conjugated states |±1/2> of the Gd3+ ion decreases with a decrease in the powder size from macrosizes to nanosizes. The observed dependence can be due to the increase in the unit cell size during grinding of the samples.

  11. Motor-dominant polyneuropathy due to IgM monoclonal antibody against disialosyl gangliosides in a patient with mantle cell lymphoma.

    PubMed

    Mori, Akio; Ueno, Yuji; Kuroki, Takuma; Hoshino, Yasunobu; Shimura, Hideki; Sekiguchi, Yasunobu; Noguchi, Masaaki; Hamada, Yukihiro; Kusunoki, Susumu; Hattori, Nobutaka; Urabe, Takao

    2014-02-15

    A rapidly progressive motor-dominant neuropathy associated with IgM monoclonal antibody against gangliosides with disialosyl residues, GD3, GD1b, GT1b, and GQ1b, in a 60-year-old Japanese man with mantle cell lymphoma is reported. Plasma exchange and chemotherapy for mantle cell lymphoma were performed for the neuropathy and mantle cell lymphoma. After therapy, the motor neuropathy dramatically improved concurrently with substantial reduction of the antibody activities especially in reaction to GD1b. This is the first case report of neuropathy with anti-disialosyl IgM antibodies associated with mantle cell lymphoma, and plasma exchange and chemotherapy were effective. PMID:24315580

  12. Biosynthesis and transport of gangliosides in peripheral nerve

    SciTech Connect

    Yates, A.J.; Tipnis, U.R.; Hofteig, J.H.; Warner, J.K.

    1984-01-01

    Radiolabelled glucosamine was injected into L-7 dorsal root ganglion (DRG) of rabbits. At several different times after injection DRG, lumbosacral trunks (LST) and sciatic nerves (SN) were removed and gangliosides extracted. Two and 3 weeks after injection the amounts of radioactivity in the ganglioside fractions of LST and SN were significantly higher than at days 1 and 2. The TCA soluble radioactivity decreased dramatically over the same time period. Colchicine prevented the appearance of radiolabelled lipid in LST and SN. From these experiments the authors conclude that some ganglioside is synthesized in the neuronal cell bodies of DRG and transported in the axons of the sciatic nerve. In another experiment the sciatic nerve was transected and ends separated to prevent regeneration. There was no difference in the amount of radiolabelled ganglioside that was isolated from DRG or LST of transected nerves compared with control nerves. The behavior of several potential acid soluble contaminants was studied in several steps used to isolate gangliosides. Of those studied only CMP-NeuAc could cause significant contamination of the final ganglioside preparation.

  13. Dielectric properties of Gd3Ba2Mn2Cu2O12 manganocuprate

    NASA Astrophysics Data System (ADS)

    Rayaprol, S.; Kaushik, S. D.; Kumar, N.; Gaur, N. K.; Saha, J.; Patnaik, S.

    2011-04-01

    The magnetocapacitance and magnetoresistance of Gd3Ba2Mn2Cu2O12 (Gd-3222) has been measured in the temperature range of 2-300 K. The capacitance increases with increasing temperature from 2-300 K, and exhibits a steplike feature at ˜95 K (for 1 kHz). On increasing the probe frequency this step gets broaden and shifts to higher temperature ˜150 K (for 75 kHz). The observation of frequency dependence in capacitance and dielectric loss (tan δ) exhibits Maxwell-Wagner type relaxor behavior in this compound. Magnetocapacitance was observed on the application of magnetic field. No observable magnetoresistance could be observed in this compound, indicating that the magnetoelectric coupling observed from the dielectric constant measurement with and without magnetic field, is of capacitive origin. The results of magnetocapacitance and magnetoresistance of the Gd-3222 compound are presented in the light of current interest in exploring manganite systems for multiferroic properties.

  14. Angle-Dependent Microresonator ESR Characterization of Locally Doped Gd3 + :Al2O3

    NASA Astrophysics Data System (ADS)

    Wisby, I. S.; de Graaf, S. E.; Gwilliam, R.; Adamyan, A.; Kubatkin, S. E.; Meeson, P. J.; Tzalenchuk, A. Ya.; Lindström, T.

    2016-08-01

    Interfacing rare-earth-doped crystals with superconducting circuit architectures provides an attractive platform for quantum memory and transducer devices. Here, we present the detailed characterization of such a hybrid system: a locally implanted rare-earth Gd3 + in Al2O3 spin system coupled to a superconducting microresonator. We investigate the properties of the implanted spin system through angular-dependent microresonator electron spin resonance (micro-ESR) spectroscopy. We find, despite the high-energy near-surface implantation, the resulting micro-ESR spectra to be in excellent agreement with the modeled Hamiltonian, supporting the integration of dopant ions into their relevant lattice sites while maintaining crystalline symmetries. Furthermore, we observe clear contributions from individual microwave field components of our microresonator, emphasizing the need for controllable local implantation.

  15. Direct ultraviolet excitation of an amorphous AlN:praseodymium phosphor by codoped Gd3+ cathodoluminescence

    NASA Astrophysics Data System (ADS)

    Maqbool, Muhammad; Ahmad, I.; Richardson, H. H.; Kordesch, M. E.

    2007-11-01

    Sputter deposited thin film amorphous AlN:Pr (1at.%) emits in the blue-green (490-530nm) and red (˜650nm) regions of the visible spectrum under electron excitation. The addition of Gd 1at.% in the film enhances the blue emission by an order of magnitude. The enhancement in the blue region is a result of cathodoluminescence from Gd3+ at 313nm. The optical bandgap of amorphous AlN is about 210nm, so that the film is transparent in the ultraviolet, allowing the Gd emission to excite the Pr3+ ions. No significant quenching of the Gd emission is observed when the Gd and Pr ions are mixed. The blue enhancement is observed even with the two films containing each of the ions that are separated by a 500μm thick quartz spacer, showing that the enhancement is due entirely to UV radiation.

  16. Association of Anti-GT1a Antibodies with an Outbreak of Guillain-Barré Syndrome and Analysis of Ganglioside Mimicry in an Associated Campylobacter jejuni Strain.

    PubMed

    Zhang, Maojun; Gilbert, Michel; Yuki, Nobuhiro; Cao, Fangfang; Li, Jianjun; Liu, Hongying; Li, Qun; Meng, Fanliang; Zhang, Jianzhong

    2015-01-01

    An outbreak of Guillain-Barré syndrome (GBS), subsequent to Campylobacter jejuni enteritis, occurred in China in 2007. Serum anti-ganglioside antibodies were measured in GBS patients and controls. Genome sequencing was used to determine the phylogenetic relationship among three C. jejuni strains from a patient with GBS (ICDCCJ07001), a patient with gastroenteritis (ICDCCJ07002) and a healthy carrier (ICDCCJ07004), which were all associated with the outbreak. The ganglioside-like structures of the lipo-oligosaccharides of these strains were determined by mass spectrometry. Seventeen (53%) of the GBS patients had anti-GT1a IgG antibodies. GT1a mimicry was found in the lipo-oligosaccharides of strain ICDCCJ07002 and ICDCCJ07004; but a combination of GM3/GD3 mimics was observed in ICDCCJ07001, although this patient had anti-GT1a IgG antibodies. A single-base deletion in a glycosyltransferase gene caused the absence of GT1a mimicry in ICDCCJ07001. The phylogenetic tree showed that ICDCCJ07002 and ICDCCJ07004 were genetically closer to each other than to ICDCCJ07001. C. jejuni, bearing a GT1a-like lipo-oligosaccharide, might have caused the GBS outbreak and the loss of GT1a mimicry may have helped ICDCCJ07001 to survive in the host.

  17. Association of Anti-GT1a Antibodies with an Outbreak of Guillain-Barré Syndrome and Analysis of Ganglioside Mimicry in an Associated Campylobacter jejuni Strain

    PubMed Central

    Cao, Fangfang; Li, Jianjun; Liu, Hongying; Li, Qun; Meng, Fanliang; Zhang, Jianzhong

    2015-01-01

    An outbreak of Guillain-Barré syndrome (GBS), subsequent to Campylobacter jejuni enteritis, occurred in China in 2007. Serum anti-ganglioside antibodies were measured in GBS patients and controls. Genome sequencing was used to determine the phylogenetic relationship among three C. jejuni strains from a patient with GBS (ICDCCJ07001), a patient with gastroenteritis (ICDCCJ07002) and a healthy carrier (ICDCCJ07004), which were all associated with the outbreak. The ganglioside-like structures of the lipo-oligosaccharides of these strains were determined by mass spectrometry. Seventeen (53%) of the GBS patients had anti-GT1a IgG antibodies. GT1a mimicry was found in the lipo-oligosaccharides of strain ICDCCJ07002 and ICDCCJ07004; but a combination of GM3/GD3 mimics was observed in ICDCCJ07001, although this patient had anti-GT1a IgG antibodies. A single-base deletion in a glycosyltransferase gene caused the absence of GT1a mimicry in ICDCCJ07001. The phylogenetic tree showed that ICDCCJ07002 and ICDCCJ07004 were genetically closer to each other than to ICDCCJ07001. C. jejuni, bearing a GT1a-like lipo-oligosaccharide, might have caused the GBS outbreak and the loss of GT1a mimicry may have helped ICDCCJ07001 to survive in the host. PMID:26197476

  18. Association of Anti-GT1a Antibodies with an Outbreak of Guillain-Barré Syndrome and Analysis of Ganglioside Mimicry in an Associated Campylobacter jejuni Strain.

    PubMed

    Zhang, Maojun; Gilbert, Michel; Yuki, Nobuhiro; Cao, Fangfang; Li, Jianjun; Liu, Hongying; Li, Qun; Meng, Fanliang; Zhang, Jianzhong

    2015-01-01

    An outbreak of Guillain-Barré syndrome (GBS), subsequent to Campylobacter jejuni enteritis, occurred in China in 2007. Serum anti-ganglioside antibodies were measured in GBS patients and controls. Genome sequencing was used to determine the phylogenetic relationship among three C. jejuni strains from a patient with GBS (ICDCCJ07001), a patient with gastroenteritis (ICDCCJ07002) and a healthy carrier (ICDCCJ07004), which were all associated with the outbreak. The ganglioside-like structures of the lipo-oligosaccharides of these strains were determined by mass spectrometry. Seventeen (53%) of the GBS patients had anti-GT1a IgG antibodies. GT1a mimicry was found in the lipo-oligosaccharides of strain ICDCCJ07002 and ICDCCJ07004; but a combination of GM3/GD3 mimics was observed in ICDCCJ07001, although this patient had anti-GT1a IgG antibodies. A single-base deletion in a glycosyltransferase gene caused the absence of GT1a mimicry in ICDCCJ07001. The phylogenetic tree showed that ICDCCJ07002 and ICDCCJ07004 were genetically closer to each other than to ICDCCJ07001. C. jejuni, bearing a GT1a-like lipo-oligosaccharide, might have caused the GBS outbreak and the loss of GT1a mimicry may have helped ICDCCJ07001 to survive in the host. PMID:26197476

  19. Role of OH Adsorption on the Properties of MRI contrast agent Gd3N@C80

    NASA Astrophysics Data System (ADS)

    Ong, Vince; Khanna, Shiv; Fatouros, Panos

    2009-03-01

    Endohedral metallofullerenes Gd3N@C80 decorated with hydroxyl groups are now known to be excellent contrast enhancement agents for Magnetic Resonance Imaging (MRI) leading to strong relaxivity enhancements. One of the outstanding issues is the nature of OH adsorption and its effect on the properties of endohedral Gd3N motif. We have carried out theoretical studies on the electronic structure and magnetic properties of the endohedral metallofullerenes functionalized with hydroxyl groups to demonstrate that the nature of OH can have significant effect on the magnetic spin density. The new findings may provide physical insight into the observed strong relaxivity enhancements.

  20. Nuclear and electronic relaxation in lanthanide solutions: (CH 3) 4N +/Gd 3+ repulsive ion pair in D 2O

    NASA Astrophysics Data System (ADS)

    Vigouroux, C.; Bardet, M.; Belorizky, E.; Fries, P. H.; Guillermo, A.

    1998-04-01

    The longitudinal relaxation rate and self-diffusion coefficient of the tetramethylammonium protons are investigated at 400 MHz in D 2O solutions of hydrated Gd 3+ paramagnetic impurities, without and with complexing NO 3- ions. The results are interpreted using the hypernetted chain approximation of the potential of mean force between the repulsive ions, approximated as charged hard spheres in discrete polar and polarizable water. The standard dipolar relaxation formalism of Solomon is valid for the Gd 3+ lanthanide, i.e. its electron relaxation time is much longer than the translational correlation time of the interionic Brownian diffusion. The coordination effect by NO 3- is analyzed.

  1. Antibody Recognition of Cancer-Related Gangliosides and Their Mimics Investigated Using in silico Site Mapping

    PubMed Central

    Agostino, Mark; Yuriev, Elizabeth; Ramsland, Paul A.

    2012-01-01

    Modified gangliosides may be overexpressed in certain types of cancer, thus, they are considered a valuable target in cancer immunotherapy. Structural knowledge of their interaction with antibodies is currently limited, due to the large size and high flexibility of these ligands. In this study, we apply our previously developed site mapping technique to investigate the recognition of cancer-related gangliosides by anti-ganglioside antibodies. The results reveal a potential ganglioside-binding motif in the four antibodies studied, suggesting the possibility of structural convergence in the anti-ganglioside immune response. The structural basis of the recognition of ganglioside-mimetic peptides is also investigated using site mapping and compared to ganglioside recognition. The peptides are shown to act as structural mimics of gangliosides by interacting with many of the same binding site residues as the cognate carbohydrate epitopes. These studies provide important clues as to the structural basis of immunological mimicry of carbohydrates. PMID:22536387

  2. Reactivity of neuroborreliosis patients (Lyme disease) to cardiolipin and gangliosides.

    PubMed

    García Moncó, J C; Wheeler, C M; Benach, J L; Furie, R A; Lukehart, S A; Stanek, G; Steere, A C

    1993-07-01

    A subset of patients (50%) with neuroborreliosis (Lyme disease) showed IgG reactivity to cardiolipin in solid phase ELISA. In addition, a subset of patients with neuroborreliosis (29%) and syphilis (59%) had IgM reactivity to gangliosides with a Gal(beta 1-3) GalNac terminal sequence (GM1, GD1b, and asialo GM1). Anti-ganglioside IgM antibodies were significantly more frequent in these two groups of patients compared to patients with cutaneous and articular Lyme disease, primary antiphospholipid syndrome, systemic lupus erythematosus and normal controls. Correlative evidence and adsorption experiments indicated that antibodies to cardiolipin had separate specificities from those directed against the gangliosides. IgM antibodies to Gal(beta 1-3) GalNac gangliosides appeared to have similar specificities since these were positively correlated and inhibitable by cross adsorption assays. Given the clinical associations of patients with neuroborreliosis and syphilis with IgM reactivity to gangliosides sharing the Gal(beta 1-3) GalNac terminus, we suggest that these antibodies could represent a response to injury in neurological disease or a cross reactive event caused by spirochetes.

  3. Ganglioside Composition in Beef, Chicken, Pork, and Fish Determined Using Liquid Chromatography-High-Resolution Mass Spectrometry.

    PubMed

    Fong, Bertram Y; Ma, Lin; Khor, Geok Lin; van der Does, Yvonne; Rowan, Angela; McJarrow, Paul; MacGibbon, Alastair K H

    2016-08-17

    Gangliosides (GA) are found in animal tissues and fluids, such as blood and milk. These sialo-glycosphingolipids have bioactivities in neural development, the gastrointestinal tract, and the immune system. In this study, a high-performance liquid chromatography-mass spectrometry (HPLC-MS) method was validated to characterize and quantitate the GA in beef, chicken, pork, and fish species (turbot, snapper, king salmon, and island mackerel). For the first time, we report the concentration of GM3, the dominant GA in these foods, as ranging from 0.35 to 1.1 mg/100 g and 0.70 to 5.86 mg/100 g of meat and fish, respectively. The minor GAs measured were GD3, GD1a, GD1b, and GT1b. Molecular species distribution revealed that the GA contained long- to very-long-chain acyl fatty acids attached to the ceramide moiety. Fish GA contained only N-acetylneuraminic acid (NeuAc) sialic acid, while beef, chicken, and pork contained GD1a/b species that incorporated both NeuAc and N-glycolylneuraminic acid (NeuGc) and hydroxylated fatty acids. PMID:27436425

  4. Gd(3+)-Based Magnetic Resonance Imaging Contrast Agent Responsive to Zn(2+).

    PubMed

    Regueiro-Figueroa, Martín; Gündüz, Serhat; Patinec, Véronique; Logothetis, Nikos K; Esteban-Gómez, David; Tripier, Raphaël; Angelovski, Goran; Platas-Iglesias, Carlos

    2015-11-01

    We report the heteroditopic ligand H5L, which contains a DO3A unit for Gd(3+) complexation connected to an NO2A moiety through a N-propylacetamide linker. The synthesis of the ligand followed a convergent route that involved the preparation of 1,4-bis(tert-butoxycarbonylmethyl)-1,4,7-triazacyclononane following the orthoamide strategy. The luminescence lifetimes of the Tb((5)D4) excited state measured for the TbL complex point to the absence of coordinated water molecules. Density functional theory calculations and (1)H NMR studies indicate that the EuL complex presents a square antiprismatic coordination in aqueous solution, where eight coordination is provided by the seven donor atoms of the DO3A unit and the amide oxygen atom of the N-propylacetamide linker. Addition of Zn(2+) to aqueous solutions of the TbL complex provokes a decrease of the emission intensity as the emission lifetime becomes shorter, which is a consequence of the coordination of a water molecule to the Tb(3+) ion upon Zn(2+) binding to the NO2A moiety. The relaxivity of the GdL complex recorded at 7 T (25 °C) increases by almost 150% in the presence of 1 equiv of Zn(2+), while Ca(2+) and Mg(2+) induced very small relaxivity changes. In vitro magnetic resonance imaging experiments confirmed the ability of GdL to provide response to the presence of Zn(2+).

  5. Magnetooptics of the luminescent transitions in Tb3+:Gd3Ga5O12

    NASA Astrophysics Data System (ADS)

    Valiev, Uygun V.; Gruber, John B.; Ivanov, Igor'A.; Burdick, Gary W.; Liang, Hongbin; Zhou, Lei; Fu, Dejun; Pelenovich, Oleg V.; Pelenovich, Vasiliy O.; Lin, Zhou

    2015-08-01

    The spectra of the luminescence and magnetic circular polarization of luminescence in terbium-gadolinium gallium garnet Tb3+:Gd3Ga5O12 (Tb3+:GGG) were studied within the visible spectral range at temperatures T = 90 and 300 K in an external magnetic field of 0.45 T. The Zeeman effect in the luminescence "green" band associated with 4f → 4f transition 5D4 → 7F5 of Tb3+:GGG was also studied at T = 90 K in an external field of 0.55 T. Measurement of the Zeeman effect in Tb3+:GGG carried out for some doublet lines of the luminescence band 5D4 → 7F5 at T = 90 K shows that a magnetooptical effect of the intensity change of the emitted light is observed on these lines, in contrast to pure Zeeman splitting of the emission lines measured in the luminescence band 5D4 → 7F6. For the systems we have studied, the maximal value of the magnetooptical effect of the intensity change of the luminescence line at low temperatures has been achieved in paramagnetic garnet Tb0.2Y2.8Al5O12 at comparatively low magnetic fields.

  6. GM1 and GM2 gangliosides: recent developments.

    PubMed

    Bisel, Blaine; Pavone, Francesco S; Calamai, Martino

    2014-03-01

    GM1 and GM2 gangliosides are important components of the cell membrane and play an integral role in cell signaling and metabolism. In this conceptual overview, we discuss recent developments in our understanding of the basic biological functions of GM1 and GM2 and their involvement in several diseases. In addition to a well-established spectrum of disorders known as gangliosidoses, such as Tay-Sachs disease, more and more evidence points at an involvement of GM1 in Alzheimer's and Parkinson's diseases. New emerging methodologies spanning from single-molecule imaging in vivo to simulations in silico have complemented standard studies based on ganglioside extraction. PMID:25372744

  7. The role of gangliosides in brain development and the potential benefits of perinatal supplementation.

    PubMed

    Ryan, Jennifer M; Rice, Gregory E; Mitchell, Murray D

    2013-11-01

    The maternal diet provides critical nutrients that can influence fetal and infant brain development and function. This review highlights the potential benefits of maternal dietary ganglioside supplementation on fetal and infant brain development. English-language systematic reviews, preclinical studies, and clinical studies were obtained through searches on PubMed. Reports were selected if they included benefits and harms of maternal ganglioside supplementation during pregnancy or ganglioside-supplemented formula after pregnancy. The potential benefits of ganglioside supplementation were explored by investigating the following: (1) their role in neural development, (2) their therapeutic use in neural injury and disease, (3) their presence in human breast milk, and (4) their use as a dietary supplement during or after pregnancy. Preclinical studies indicate that ganglioside supplementation at high doses (1% of total dietary intake) can significantly increase cognitive development and body weight when given prenatally. However, lower ganglioside supplementation doses have no beneficial cognitive effects, even when given throughout pregnancy and lactation. In human clinical trials, infants given formula supplemented with gangliosides showed increased cognitive development and an increase in ganglioside content. Ganglioside supplementation may promote brain development and function in offspring when administered at the optimum dosage. We propose that prenatal maternal dietary supplementation with gangliosides throughout pregnancy may promote greater long-term effects on brain development and function. Before this concept can be encouraged in preconception clinics, future research and clinical trials are needed to confirm the ability of dietary gangliosides to improve cognitive development, but available results already encourage this area of research.

  8. Surfactant-free Gd3+-ion-containing carbon nanotube MRI contrast agents for stem cell labeling

    NASA Astrophysics Data System (ADS)

    Gizzatov, Ayrat; Hernández-Rivera, Mayra; Keshishian, Vazrik; Mackeyev, Yuri; Law, Justin J.; Guven, Adem; Sethi, Richa; Qu, Feifei; Muthupillai, Raja; Cabreira-Hansen, Maria Da Graça; Willerson, James T.; Perin, Emerson C.; Ma, Qing; Bryant, Robert G.; Wilson, Lon J.

    2015-07-01

    There is an ever increasing interest in developing new stem cell therapies. However, imaging and tracking stem cells in vivo after transplantation remains a serious challenge. In this work, we report new, functionalized and high-performance Gd3+-ion-containing ultra-short carbon nanotube (US-tube) MRI contrast agent (CA) materials which are highly-water-dispersible (ca. 35 mg ml-1) without the need of a surfactant. The new materials have extremely high T1-weighted relaxivities of 90 (mM s)-1 per Gd3+ ion at 1.5 T at room temperature and have been used to safely label porcine bone-marrow-derived mesenchymal stem cells for MR imaging. The labeled cells display excellent image contrast in phantom imaging experiments, and TEM images of the labeled cells, in general, reveal small clusters of the CA material located within the cytoplasm with 109 Gd3+ ions per cell.There is an ever increasing interest in developing new stem cell therapies. However, imaging and tracking stem cells in vivo after transplantation remains a serious challenge. In this work, we report new, functionalized and high-performance Gd3+-ion-containing ultra-short carbon nanotube (US-tube) MRI contrast agent (CA) materials which are highly-water-dispersible (ca. 35 mg ml-1) without the need of a surfactant. The new materials have extremely high T1-weighted relaxivities of 90 (mM s)-1 per Gd3+ ion at 1.5 T at room temperature and have been used to safely label porcine bone-marrow-derived mesenchymal stem cells for MR imaging. The labeled cells display excellent image contrast in phantom imaging experiments, and TEM images of the labeled cells, in general, reveal small clusters of the CA material located within the cytoplasm with 109 Gd3+ ions per cell. Electronic supplementary information (ESI) available: NMRD profiles, the Fourier transforms of the EXAFS data, EXAFS curve fitting data, cell viability data. See DOI: 10.1039/c5nr02078f

  9. Electrical and electromechanical studies in ferroelectric Gd3+ modified lead potassium niobate ceramics

    NASA Astrophysics Data System (ADS)

    Sambasiva Rao, K.; Krishna, P. Murali; Dasari, Madhava P.; Lee, J. H.

    2011-08-01

    The change in dielectric constant relaxation time over temperature (35-590 °C) and frequency (45 Hz-5 MHz) in ceramics of Pb0.77K0.115Gd0.115Nb2O6 (PKGN, Tc = 340 °c) has been studied. Powder X-ray diffraction revealed the single-phase formation with orthorhombic crystal structure. The P-E hysteresis loop parameters are Ps = 21.77 μC/cm2, Pr = 17.09 μC/cm2, Ec = 11.86 kV/cm; the piezoelectric constants, Kp = 31.7%, Kt = 47%, d33 = 115 × 10-12 C/N, d31 = -41 × 10-12 C/N, are determined in the material and some transducer applications are discussed. Cole-Cole (Zll vs. Zl) plots showed a non-Debye type relaxation. Conductivity obeyed Jonscher's universal power law, σ = σ0 + Aωn. The theoretical values of ɛl and σ are computed using the parameters `A(T)' and `n(T)' (0 < n < 1) and are well fitted with the experimental data. The hopping ion frequency (ωp) and charge carrier concentration (Kl) have been analyzed using Almond-West formalism. The dielectric relaxation processes are associated with localized oxygen vacancies conduction at high frequency region. A long-range conductivity by Gd3+ ions is found to be predominant at low frequency region. The activation energies from impedance and modulus formalisms revealed the ionic type conduction in PKGN.

  10. Subcellular Partitioning and Analysis of Gd3+-Loaded Ultrashort Single-Walled Carbon Nanotubes.

    PubMed

    Holt, Brian D; Law, Justin J; Boyer, Patrick D; Wilson, Lon J; Dahl, Kris Noel; Islam, Mohammad F

    2015-07-15

    Magnetic resonance imaging (MRI) is of vast clinical utility, with tens of millions of scans performed annually. Chemical contrast agents (CAs) can greatly enhance the diagnostic potential of MRI, and ∼50% of MRI scans use CAs. However, CAs have significant limitations such as low contrast enhancement, lack of specificity, and potential toxicity. Recently developed, Gd3+-loaded ultrashort single-walled carbon nanotubes, also referred to as gadonanotubes or GNTs, exhibit ∼40 times the relaxivities of clinical CAs, representing a potential major advance in clinically relevant MRI CA materials. Although initial cytotoxicity and MRI studies have suggested great promise for GNTs, relatively little is known regarding their subcellular interactions, which are crucial for further, safe development of GNTs as CAs. In this work, we administered GNTs to a well-established human cell line (HeLa) and to murine macrophage-like cells (J774A.1). GNTs were not acutely cytotoxic and did not reduce proliferation, except for the highest exposure concentration of 27 μg/mL for J774A.1 macrophages, yet bulk uptake of GNTs occurred in minutes at picogram quantities, or millions of GNTs per cell. J774A.1 macrophages internalized substantially more GNTs than HeLa cells in a dose-dependent manner, and Raman imaging of the subcellular distribution of GNTs revealed perinuclear localization. Fluorescence intensity and lifetime imaging demonstrated that GNTs did not grossly alter subcellular compartments, including filamentous-actin structures. Together, these results provide subcellular evidence necessary to establish GNTs as a new MRI CA material.

  11. Cholera Toxin and Cell Growth: Role of Membrane Gangliosides

    PubMed Central

    Hollenberg, Morley D.; Fishman, Peter H.; Bennett, Vann; Cuatrecasas, Pedro

    1974-01-01

    The binding of cholera toxin to three transformed mouse cell lines derived from the same parent strain, and the effects of the toxin on DNA synthesis and adenylate cyclase activity, vary in parallel with the ganglioside composition of the cells. TAL/N cells of early passage, which contain large quantities of gangliosides GM3, GM2, GM1, and GDla, as well as the glycosyltransferases necessary for the synthesis of these gangliosides, bind the most cholera toxin and are the most sensitive to its action. TAL/N cells of later passage, which lack chemically detectable GM1 and GDla and which have no UDP-Gal:GM2 galactosyltransferase activity, are intermediate in binding and response to the toxin. SVS AL/N cells, which lack GM2 in addition to GM1 and GDla and which have little detectable UDP-GalNAc:GM3N-acetylgalactosaminyltransferase activity, bind the least amount of toxin. The SVS AL/N cells are the least responsive to inhibition of DNA synthesis and stimulation of adenylate cyclase activity by cholera toxin. Gangliosides (especially GM1), which appear to be the natural membrane receptors for cholera toxin, may normally have important roles in the regulation of cell growth and cAMP-mediated responses. PMID:4530298

  12. Controlling the Two-Photon-Induced Photon Cascade Emission in a Gd3+/Tb3+-Codoped Glass for Multicolor Display

    PubMed Central

    Yuan, Mao-Hui; Fan, Hai-Hua; Li, Hui; Lan, Sheng; Tie, Shao-Long; Yang, Zhong-Min

    2016-01-01

    We reported the first observation of the two-photon-induced quantum cutting phenomenon in a Gd3+/Tb3+-codoped glass in which two photons at ~400 nm are simultaneously absorbed, leading to the cascade emission of three photons in the visible spectral region. The two-photon absorption induced by femtosecond laser pulses allows the excitation of the energy states in Gd3+ which are inactive for single-photon excitation and enables the observation of many new electric transitions which are invisible in the single-photon-induced luminescence. The competition between the two-photon-induced photon cascade emission and the single-photon-induced emission was manipulated to control the luminescence color of the glass. We demonstrated the change of the luminescence color from red to yellow and eventually to green by varying either the excitation wavelength or the excitation power density. PMID:26899189

  13. Effect of Gd3+- Cr3+ ion substitution on the structural, electrical and magnetic properties of Ni - Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Anupama, M. K.; Rudraswamy, B.

    2016-09-01

    Gd3+ doped nickel zinc nanoceramics with general formula Ni0.4Zn0.6Cr0.5GdxFe1.5 - xO4 (where x=0.00, 0.02, 0.04, 0.06) were synthesized by solution combustion method using oxylyldehydrazine as a fuel. The obtained powder was sintered at 1000°C for 2h. The detailed structural, electrical and magnetic studies were carried out through X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), impedance spectroscopy and vibrating sample magnetometer (VSM). The XRD pattern of as prepared sample confirms the formation of single phase with cubic spinel structure. The average crystallite size was found to be 34 to 19 nm and decreases with increasing Gd3+ ion concentration. The IR spectra exhibited two expected absorption bands between 600 to 300 cm-1 corresponding to the stretching vibrations of tetrahedral (A) and octahedral (B) metal oxygen vibrations. The variation of room temperature real (ε') and imaginary (ε") part of dielectric permittivity as a function of frequency and composition have been studied in the frequency range from 40Hz to 10MHz. The real and imaginary dielectric permittivity decreases with increase in frequency as well as Gd3+ concentration, which is normal behaviour of ferrite material and results have been explained on the basis of Maxwell - Wagner's two layer model. The VSM results showed that the Gd3+ concentration had significant impact on the saturation magnetization and coercivity, x = 0.02 shows the highest value of dielectric constant and saturation magnetization, thus the material is becoming low loss dielectric and highly resistive and soft magnetic material due to Gd-Cr doping.

  14. Investigations of the spin Hamiltonian parameters and defect structure for the rhombic Gd3+ center in calcium oxide

    NASA Astrophysics Data System (ADS)

    Wu, S. Y.; Dongo, H. N.; Lin, J. Z.; Fu, Q.

    2006-09-01

    The spin Hamiltonian (SH) parameters (zero-field splittings, b(2)(0), b(2)(2), b(4)(0), b(4)(2), b(4)(4), b(6)(0) and b(6)(6)) and the defect structure for the rhombic Gd3+ center in CaO are theoretically investigated by the superposition model. Meanwhile, the g-factor is also quantitatively studied from the approximation formula on the basis of an admixture of the ground S-8(7/2) and the excited L-6(7/2) (L = P, D, F, G) states via the spin-orbit coupling interactions. The defect structure of this center can be described by the impurity Gd3+ occupying the host octahedral Ca2+ site, associated with one nearest neighbouring cation vacancy V-Ca in the [110] direction. On the basis of these studies, the impurity Gd3+ is found to shift towards the V-Ca along the [110] axis by about 0.582 angstrom, whereas the oxygen ligands closest to the V-Ca suffer a displacement towards the latter by about 0.211 angstrom. The calculated SH parameters based on the earlier analyses show reasonable agreement with the observed values.

  15. Bifunctional heterometallic Ln3+-Gd3+ (Ln = Eu, Tb) hybrid silica microspheres: luminescence and MRI contrast agent property.

    PubMed

    Li, Yan-Yan; Yan, Bing; Li, Qiu-Ping

    2013-02-01

    A novel series of homometallic and heterometallic lanthanide (Eu(3+)(Tb(3+))-Gd(3+)) hybrid silica microspheres (EDTA-(Eu(Tb)-Gd)-TTA-SiO(2)) are synthesized with 2-thenoyltrifluoroacetone (TTA) functionalized silane and ethylenediaminetetraacetic acid (EDTA) by sol-gel process, whose physical characterization are carried out and especially the luminescence and the magnetic resonance imaging (MRI) contrast agent properties are discussed. These hybrids present uniform silica microsphere morphology with particle size of 1 μm. Comparing to the homometallic hybrid silica microsphere EDTA-Ln-TTA-SiO(2) without Gd(3+) ion, the heterometallic hybrid silica microspheres EDTA-Eu-Gd-TTA-SiO(2) exhibit stronger luminescent intensity, longer lifetime and higher luminescent quantum efficiency, which is due to the fact that inert ion Gd(3+) can enhance the luminescence of the Eu(3+) or Tb(3+) within the hybrid system. In addition, the MRI relaxivity of the heterometallic lanthanide hybrid silica microspheres in water is assessed, showing a lower T1 relaxation rate than homometallic gadolinium hybrid one (EDTA-Gd-TTA-SiO(2)). Both of them show higher T1 relaxation rate than the conventional Gd chelate of diethylenetriamine pentaacetic acid. These bifunctional hybrid materials exhibit both luminescent and MRI magnetic contrast agent properties, whose further investigation can be expected to have potential application in practical fields such as optical storage and sensors, etc. PMID:23154785

  16. Double-phase transition and giant positive magnetoresistance in the quasi-skutterudite Gd3Ir4Sn13

    NASA Astrophysics Data System (ADS)

    Nair, Harikrishnan S.; Ghosh, Sarit K.; Ramesh Kumar, K.; Strydom, André M.

    2016-03-01

    The magnetic, thermodynamic, and electrical/thermal transport properties of the caged-structure quasi-skutterudite Gd3Ir4Sn13 are re-investigated. The magnetization M(T), the specific heat C p ( T ) , and the resistivity ρ ( T ) reveal a double-phase transition—at TN1 ˜ 10 K and at TN2 ˜ 8.8 K—which was not observed in the previous report on this compound. The antiferromagnetic transition is also visible in the thermal transport data, thereby suggesting a close connection between the electronic and lattice degrees of freedom in this Sn-based quasi-skutterudite. The temperature dependence of ρ ( T ) is analyzed in terms of a power-law for resistivity pertinent to Fermi liquid picture. Giant, positive magnetoresistance (MR) ≈ 80% is observed in Gd3Ir4Sn13 at 2 K with the application of 9 T. The giant MR and the double magnetic transition can be attributed to the quasi-cages and layered antiferromagnetic structure of Gd3Ir4Sn13 vulnerable to structural distortions and/or dipolar or spin-reorientation effects. The giant value of MR observed in this class of 3:4:13 type alloys, especially in a Gd-compound, is the highlight of this work.

  17. The effects of Gd3+ doping on the physical structure and photocatalytic performance of Bi2MoO6 nanoplate crystals

    NASA Astrophysics Data System (ADS)

    Yu, Changlin; Wu, Zhen; Liu, Renyue; He, Hongbo; Fan, Wenhong; Xue, Shuangshuang

    2016-06-01

    Gd3+ doped Bi2MoO6 nanoplate crystals were fabricated by solvothermal combined calcination method. The effects of Gd3+ doping with different concentrations on the texture, crystal and optical properties of Bi2MoO6 were investigated by N2 physical adsorption, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS), photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Under simulated solar light irradiation, the influences of Gd3+doping on photocatalytic activity of Bi2MoO6 were evaluated by photocatalytic degradation of Rhodamine B. The characterization results showed that with Gd3+ doping, a contraction of lattice and a decrease in crystallite size occurred. Meanwhile, an increase in surface area over Gd3+ doped Bi2MoO6 was observed. Moreover, Gd3+ doping could obviously enhance the visible light harvesting of Bi2MoO6 and promoted the separation of photogenerated electrons and holes. With optimum Gd3+(6 wt%) doping, Gd/Bi2MoO6 exhibited the best activity and stability in degradation of Rhodamine B.

  18. Effect of a chimeric anti-ganglioside GM2 antibody on ganglioside GM2-expressing human solid tumors in vivo.

    PubMed

    Fukumoto, H; Nishio, K; Ohta, S; Hanai, N; Fukuoka, K; Ohe, Y; Sugihara, K; Kodama, T; Saijo, N

    1999-08-27

    Ganglioside GM2 is expressed on the surface of neuroblastoma and glioblastoma cells, and may also be detected on lung cancer cells. We reported previously that anti-ganglioside GM2 antibody exhibited strong in vitro anti-tumor activity against adriamycin-resistant cancer cells, which overexpressed ganglioside GM2. In the present study, we examined the in vivo anti-tumor effect of the chimeric anti-ganglioside GM2 antibody, KM966, against human lung and breast carcinoma cells, SBC-3 and MCF-7, and respective adriamycin-resistant clones, SBC-3/ADM and AdrR MCF-7 in BALB/c nu/nu mice. Ratios of tumor volume (T/C) between KM966-treated group and control group were 0.01 for SBC-3, 0.00 for SBC-3/ADM, 0.85 for MCF-7 and 0.34 for AdrR MCF-7 cells, respectively. Nude mice, which were pretreated with anti-asialo GM1 antibody to remove natural killer cells, were transplanted with 4 x 10(7) of SBC-3 and SBC-3/ADM subcutaneously. Seven days later, when tumors had grown to a diameter of over 8 mm, mice began to receive intravenous treatment of 120 microgram/mouse KM966 daily. Fourteen daily treatments induced regression to less than 4-mm diameter in 4/5 SBC-3 tumors and 5/5 of SBC-3/ADM tumors. All SBC-3/ADM tumors disappeared completely, suggesting that KM966 exerts a strong in vivo anti-tumor effect on ganglioside GM2-expressing cancer cells. In KM966-treated mice, the surface of the tumor cells stained positive with anti-human IgG. In addition, numerous leukocytes had infiltrated into the tumor mass. Antibody-dependent cell-mediated cytotoxicity (ADCC) of KM966 against tumor cells was examined in vitro by (51)Cr-release assay and revealed that KM966 induces ADCC activity against ganglioside GM2-expressing tumors. Our results suggest that immunotherapy using KM966 may be useful for the treatment of ganglioside GM2-expressing solid tumors.

  19. Cancer vaccines: an update with special focus on ganglioside antigens.

    PubMed

    Bitton, Roberto J; Guthmann, Marcel D; Gabri, Mariano R; Carnero, Ariel J L; Alonso, Daniel F; Fainboim, Leonardo; Gomez, Daniel E

    2002-01-01

    Vaccine development is one of the most promising and exciting fields in cancer research; numerous approaches are being studied to developed effective cancer vaccines. The aim of this form of therapy is to teach the patient's immune system to recognize the antigens expressed in tumor cells, but not in normal tissue, to be able to destroy these abnormal cells leaving the normal cells intact. In other words, is an attempt to teach the immune system to recognize antigens that escaped the immunologic surveillance and are by it, therefore able to survive and, in time, disseminate. However each research group developing a cancer vaccine, uses a different technology, targeting different antigens, combining different carriers and adjuvants, and using different immunization schedules. Most of the vaccines are still experimental and not approved by the US or European Regulatory Agencies. In this work, we will offer an update in the knowledge in cancer immunology and all the anticancer vaccine approaches, with special emphasis in ganglioside based vaccines. It has been demonstrated that quantitative and qualitative changes occur in ganglioside expression during the oncogenic transformation. Malignant transformation appears to activate enzymes associated with ganglioside glycosylation, resulting in altered patterns of ganglioside expression in tumors. Direct evidence of the importance of gangliosides as potential targets for active immunotherapy has been suggested by the observation that human monoclonal antibodies against these glycolipids induce shrinkage of human cutaneous melanoma metastasis. Thus, the cellular over-expression and shedding of gangliosides into the interstitial space may play a central role in cell growth regulation, immune tolerance and tumor-angiogenesis, therefore representing a new target for anticancer therapy. Since 1993 researchers at the University of Buenos Aires and the University of Quilmes (Argentina), have taken part in a project carried out by

  20. Zika virus and neurologic autoimmunity: the putative role of gangliosides.

    PubMed

    Anaya, Juan-Manuel; Ramirez-Santana, Carolina; Salgado-Castaneda, Ignacio; Chang, Christopher; Ansari, Aftab; Gershwin, M Eric

    2016-03-21

    An increasing number of severe neurological complications associated with Zika virus (ZIKV), chiefly Guillain-Barré syndrome (GBS) and primary microcephaly, have led the World Health Organization to declare a global health emergency. Molecular mimicry between glycolipids and surface molecules of infectious agents explain most of the cases of GBS preceded by infection, while a direct toxicity of ZIKV on neural cells has been raised as the main mechanism by which ZIKV induces microcephaly. Gangliosides are crucial in brain development, and their expression correlates with neurogenesis, synaptogenesis, synaptic transmission, and cell proliferation. Targeting the autoimmune response to gangliosides may represent an underexploited opportunity to examine the increased incidence of neurological complications related to ZIKV infection.

  1. Anti-ganglioside antibodies are removed from circulation in mice by neuronal endocytosis.

    PubMed

    Cunningham, Madeleine E; McGonigal, Rhona; Meehan, Gavin R; Barrie, Jennifer A; Yao, Denggao; Halstead, Susan K; Willison, Hugh J

    2016-06-01

    SEE VAN DOORN AND JACOBS DOI101093/BRAIN/AWW078 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE  : In axonal forms of Guillain-Barré syndrome, anti-ganglioside antibodies bind gangliosides on nerve surfaces, thereby causing injury through complement activation and immune cell recruitment. Why some nerve regions are more vulnerable than others is unknown. One reason may be that neuronal membranes with high endocytic activity, including nerve terminals involved in neurotransmitter recycling, are able to endocytose anti-ganglioside antibodies from the cell surface so rapidly that antibody-mediated injury is attenuated. Herein we investigated whether endocytic clearance of anti-ganglioside antibodies by nerve terminals might also be of sufficient magnitude to deplete circulating antibody levels. Remarkably, systemically delivered anti-ganglioside antibody in mice was so avidly cleared from the circulation by endocytosis at ganglioside-expressing plasma membranes that it was rapidly rendered undetectable in serum. A major component of the clearance occurred at motor nerve terminals of neuromuscular junctions, from where anti-ganglioside antibody was retrogradely transported to the motor neuron cell body in the spinal cord, recycled to the plasma membrane, and secreted into the surrounding spinal cord. Uptake at the neuromuscular junction represents a major unexpected pathway by which pathogenic anti-ganglioside antibodies, and potentially other ganglioside binding proteins, are cleared from the systemic circulation and also covertly delivered to the central nervous system.

  2. Anti-ganglioside antibodies are removed from circulation in mice by neuronal endocytosis

    PubMed Central

    Cunningham, Madeleine E.; McGonigal, Rhona; Meehan, Gavin R.; Barrie, Jennifer A.; Yao, Denggao; Halstead, Susan K.

    2016-01-01

    See van Doorn and Jacobs (doi:10.1093/brain/aww078) for a scientific commentary on this article.   In axonal forms of Guillain-Barré syndrome, anti-ganglioside antibodies bind gangliosides on nerve surfaces, thereby causing injury through complement activation and immune cell recruitment. Why some nerve regions are more vulnerable than others is unknown. One reason may be that neuronal membranes with high endocytic activity, including nerve terminals involved in neurotransmitter recycling, are able to endocytose anti-ganglioside antibodies from the cell surface so rapidly that antibody-mediated injury is attenuated. Herein we investigated whether endocytic clearance of anti-ganglioside antibodies by nerve terminals might also be of sufficient magnitude to deplete circulating antibody levels. Remarkably, systemically delivered anti-ganglioside antibody in mice was so avidly cleared from the circulation by endocytosis at ganglioside-expressing plasma membranes that it was rapidly rendered undetectable in serum. A major component of the clearance occurred at motor nerve terminals of neuromuscular junctions, from where anti-ganglioside antibody was retrogradely transported to the motor neuron cell body in the spinal cord, recycled to the plasma membrane, and secreted into the surrounding spinal cord. Uptake at the neuromuscular junction represents a major unexpected pathway by which pathogenic anti-ganglioside antibodies, and potentially other ganglioside binding proteins, are cleared from the systemic circulation and also covertly delivered to the central nervous system. PMID:27017187

  3. Ganglioside GD2-specific trifunctional surrogate antibody Surek demonstrates therapeutic activity in a mouse melanoma model

    PubMed Central

    2012-01-01

    Background Trifunctional bispecific antibodies (trAb) are a special class of bispecific molecules recruiting and activating T cells and accessory immune cells simultaneously at the targeted tumor. The new trAb Ektomab that targets the melanoma-associated ganglioside antigen GD2 and the signaling molecule human CD3 (hCD3) on T cells demonstrated potent T-cell activation and tumor cell destruction in vitro. However, the relatively low affinity for the GD2 antigen raised the question of its therapeutic capability. To further evaluate its efficacy in vivo it was necessary to establish a mouse model. Methods We generated the surrogate trAb Surek, which possesses the identical anti-GD2 binding arm as Ektomab, but targets mouse CD3 (mCD3) instead of hCD3, and evaluated its chemical and functional quality as a therapeutic antibody homologue. The therapeutic and immunizing potential of Surek was investigated using B78-D14, a B16 melanoma transfected with GD2 and GD3 synthases and showing strong GD2 surface expression. The induction of tumor-associated and autoreactive antibodies was evaluated. Results Despite its low affinity of approximately 107 M-1 for GD2, Surek exerted efficient tumor cell destruction in vitro at an EC50 of 70ng/ml [0.47nM]. Furthermore, Surek showed strong therapeutic efficacy in a dose-dependent manner and is superior to the parental GD2 mono-specific antibody, while the use of a control trAb with irrelevant target specificity had no effect. The therapeutic activity of Surek was strictly dependent on CD4+ and CD8+ T cells, and cured mice developed a long-term memory response against a second challenge even with GD2-negative B16 melanoma cells. Moreover, tumor protection was associated with humoral immune responses dominated by IgG2a and IgG3 tumor-reactive antibodies indicating a Th1-biased immune response. Autoreactive antibodies against the GD2 target antigen were not induced. Conclusion Our data suggest that Surek revealed strong tumor elimination

  4. Assessment of the Molecular Expression and Structure of Gangliosides in Brain Metastasis of Lung Adenocarcinoma by an Advanced Approach Based on Fully Automated Chip-Nanoelectrospray Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zamfir, Alina D.; Serb, Alina; Vukeli, Željka; Flangea, Corina; Schiopu, Catalin; Fabris, Dragana; Kalanj-Bognar, Svjetlana; Capitan, Florina; Sisu, Eugen

    2011-12-01

    Gangliosides (GGs), sialic acid-containing glycosphingolipids, are known to be involved in the invasive/metastatic behavior of brain tumor cells. Development of modern methods for determination of the variations in GG expression and structure during neoplastic cell transformation is a priority in the field of biomedical analysis. In this context, we report here on the first optimization and application of chip-based nanoelectrospray (NanoMate robot) mass spectrometry (MS) for the investigation of gangliosides in a secondary brain tumor. In our work a native GG mixture extracted and purified from brain metastasis of lung adenocarcinoma was screened by NanoMate robot coupled to a quadrupole time-of-flight MS. A native GG mixture from an age-matched healthy brain tissue, sampled and analyzed under identical conditions, served as a control. Comparative MS analysis demonstrated an evident dissimilarity in GG expression in the two tissue types. Brain metastasis is characterized by many species having a reduced N-acetylneuraminic acid (Neu5Ac) content, however, modified by fucosylation or O-acetylation such as Fuc-GM4, Fuc-GM3, di- O-Ac-GM1, O-Ac-GM3. In contrast, healthy brain tissue is dominated by longer structures exhibiting from mono- to hexasialylated sugar chains. Also, significant differences in ceramide composition were discovered. By tandem MS using collision-induced dissociation at low energies, brain metastasis-associated GD3 (d18:1/18:0) species as well as an uncommon Fuc-GM1 (d18:1/18:0) detected in the normal brain tissue could be structurally characterized. The novel protocol was able to provide a reliable compositional and structural characterization with high analysis pace and at a sensitivity situated in the fmol range.

  5. Helicobacter pylori-binding gangliosides of human gastric adenocarcinoma.

    PubMed

    Roche, N; Larsson, T; Angström, J; Teneberg, S

    2001-11-01

    Acidic and neutral glycosphingolipids were isolated from a human gastric adenocarcinoma, and binding of Helicobacter pylori to the isolated glycosphingolipids was assessed using the chromatogram binding assay. The isolated glycosphingolipids were characterized using fast atom bombardment mass spectrometry and by binding of antibodies and lectins. The predominating neutral glycosphingolipids were found to migrate in the di- to tetraglycosylceramide regions as revealed by anisaldehyde staining and detection with lectins. No binding of H. pylori to these compounds was obtained. The most abundant acidic glycosphingolipids, migrating as the GM3 ganglioside and sialyl-neolactotetraosylceramide, were not recognized by the bacteria. Instead, H. pylori selectively interacted with slow-migrating, low abundant gangliosides not detected by anisaldehyde staining. Binding-active gangliosides were isolated and characterized by mass spectrometry, proton nuclear magnetic resonance, and lectin binding as sialyl-neolactohexaosylceramide (NeuAcalpha3Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer) and sialyl-neolactooctaosylceramide (NeuAcalpha3Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer).

  6. The detection limit of a Gd3+-based T1 agent is substantially reduced when targeted to a protein microdomain

    PubMed Central

    Hanaoka, Kenjiro; Lubag, Angelo Josue M.; Castillo-Muzquiz, Aminta; Kodadek, Thomas; Sherry, A. Dean

    2008-01-01

    Simple low MW chelates of Gd3+ such as those currently used in clinical MR imaging are considered too insensitive for most molecular imaging applications. Here, we evaluated the detection limit of a molecularly targeted, low MW Gd3+-based, T1 agent in a model where the receptor concentration was precisely known. The data demonstrate that receptors clustered together to form a microdomain of high local concentration can be imaged successfully even when the bulk concentration of the receptor is quite low. A GdDO3A-peptide identified by phage display to target the anti-FLAG antibody was synthesized, purified and characterized. T1 weighted MR images were compared with the agent bound to antibody in bulk solution and with the agent bound to the antibody localized on agarose beads. Fluorescence competition binding assays show that the agent has a high binding affinity (KD = 150 nM) for the antibody while the fully bound relaxivity of the GdDO3A-peptide:anti-FLAG antibody in solution was a relatively modest 17 mM−1s−1. The agent:antibody complex was MR silent at concentrations below ~9 µM but was detectable down to 4 µM bulk concentrations when presented to antibody clustered together on the surface of agarose beads. These results provided an estimate of the detection limits for other T1-based agents with higher fully bound relaxivities or multimeric structures bound to clustered receptor molecules. The results demonstrate that the sensitivity of molecularly-targeted contrast agents depends on the local microdomain concentration of the target protein and the molecular relaxivity of the bound complex. A model is presented which predicts that for a molecularly targeted agent consisting of a single Gd3+ complex with bound relaxivity of 100 mM−1s−1 or, more reasonably, four tethered Gd3+ complexes each having a bound relaxivity of 25 mM−1s−1, the detection limit of a protein microdomain is ~690 nM at 9.4T. These experimental and extrapolated detection limits are

  7. Simultaneous dual-wavelength laser operation at 937 and 1062 nm in Nd3+:Gd3Ga5O12

    NASA Astrophysics Data System (ADS)

    Gao, F.; Sun, G. C.; Li, Y. D.; Dong, Y.; Li, S. T.

    2013-08-01

    Diode-end-pumped continuous-wave (cw) simultaneous dual-wavelength laser operation at 937 and 1062 nm in a single Nd3+:Gd3Ga5O12 (Nd:GGG) crystal was demonstrated. A total output power of 1.12 W at the two fundamental wavelengths was achieved at incident pump power of 17.6 W. The optical-to-optical conversion was up to 6.4% with respect to the incident pump power. To the best of our knowledge, this is first work on cw simultaneous dual-wavelength operation at 937 and 1062 nm in Nd:GGG crystal.

  8. Improving the MR Imaging Sensitivity of Upconversion Nanoparticles by an Internal and External Incorporation of the Gd(3+) Strategy for in Vivo Tumor-Targeted Imaging.

    PubMed

    Du, Hongli; Yu, Jiani; Guo, Dongcai; Yang, Weitao; Wang, Jun; Zhang, Bingbo

    2016-02-01

    Gd(3+)-ion-doped upconversion nanoparticles (UCNPs), integrating the advantages of upconversion luminescence and magnetic resonance imaging (MRI) modalities, are capturing increasing attention because they are promising to improve the accuracy of diagnosis. The embedded Gd(3+) ions in UCNPs, however, have an indistinct MRI enhancement owing to the inefficient exchange of magnetic fields with the surrounding water protons. In this study, a novel approach is developed to improve the MR imaging sensitivity of Gd(3+)-ion-doped UCNPs. Bovine serum albumin (BSA) bundled with DTPA-Gd(3+) (DTPA(Gd)) is synthesized both as the MR imaging sensitivity synergist and phase-transfer ligand for the surface engineering of UCNPs. The external Gd(3+) ion attachment strategy is found to significant improve the MR imaging sensitivity of Gd(3+)-ion-doped UCNPs. The relaxivity analysis shows that UCNPs@BSA·DTPA(Gd) exhibit higher relaxivity values than do UCNPs@BSA without DTPA(Gd) moieties. Another relaxivity study discloses a striking message that the relaxivity value does not always reflect the realistic MRI enhancement capability. The high concentration of Gd(3+)-ion-containing UCNPs with further surface-engineered BSA·DTPA(Gd) (denoted as UCNPs-H@BSA·DTPA(Gd)) exhibits a more pronounced MRI enhancement capability compared to the other two counterparts [UCNPs-N@BSA·DTPA(Gd) and UCNPs-L@BSA·DTPA(Gd) (-N and -L are denoted as zero and low concentrations of Gd(3+) ion doping, respectively)], even though it holds the lowest r1 of 1.56 s(-1) per mmol L(-1) of Gd(3+). The physicochemical properties of UCNPs are essentially maintained after BSA·DTPA(Gd) surface decoration with good colloidal stability, in addition to improving the MR imaging sensitivity. In vivo T1-weighted MRI shows potent tumor-enhanced MRI with UCNPs-H@BSA·DTPA(Gd). An in vivo biodistribution study indicates that it is gradually excreted from the body via hepatobiliary and renal processing with no obvious

  9. Improving the MR Imaging Sensitivity of Upconversion Nanoparticles by an Internal and External Incorporation of the Gd(3+) Strategy for in Vivo Tumor-Targeted Imaging.

    PubMed

    Du, Hongli; Yu, Jiani; Guo, Dongcai; Yang, Weitao; Wang, Jun; Zhang, Bingbo

    2016-02-01

    Gd(3+)-ion-doped upconversion nanoparticles (UCNPs), integrating the advantages of upconversion luminescence and magnetic resonance imaging (MRI) modalities, are capturing increasing attention because they are promising to improve the accuracy of diagnosis. The embedded Gd(3+) ions in UCNPs, however, have an indistinct MRI enhancement owing to the inefficient exchange of magnetic fields with the surrounding water protons. In this study, a novel approach is developed to improve the MR imaging sensitivity of Gd(3+)-ion-doped UCNPs. Bovine serum albumin (BSA) bundled with DTPA-Gd(3+) (DTPA(Gd)) is synthesized both as the MR imaging sensitivity synergist and phase-transfer ligand for the surface engineering of UCNPs. The external Gd(3+) ion attachment strategy is found to significant improve the MR imaging sensitivity of Gd(3+)-ion-doped UCNPs. The relaxivity analysis shows that UCNPs@BSA·DTPA(Gd) exhibit higher relaxivity values than do UCNPs@BSA without DTPA(Gd) moieties. Another relaxivity study discloses a striking message that the relaxivity value does not always reflect the realistic MRI enhancement capability. The high concentration of Gd(3+)-ion-containing UCNPs with further surface-engineered BSA·DTPA(Gd) (denoted as UCNPs-H@BSA·DTPA(Gd)) exhibits a more pronounced MRI enhancement capability compared to the other two counterparts [UCNPs-N@BSA·DTPA(Gd) and UCNPs-L@BSA·DTPA(Gd) (-N and -L are denoted as zero and low concentrations of Gd(3+) ion doping, respectively)], even though it holds the lowest r1 of 1.56 s(-1) per mmol L(-1) of Gd(3+). The physicochemical properties of UCNPs are essentially maintained after BSA·DTPA(Gd) surface decoration with good colloidal stability, in addition to improving the MR imaging sensitivity. In vivo T1-weighted MRI shows potent tumor-enhanced MRI with UCNPs-H@BSA·DTPA(Gd). An in vivo biodistribution study indicates that it is gradually excreted from the body via hepatobiliary and renal processing with no obvious

  10. Novel Ganglioside-mediated Entry of Botulinum Neurotoxin Serotype D into Neurons

    SciTech Connect

    Kroken, Abby R.; Karalewitz, Andrew P.-A.; Fu, Zhuji; Kim, Jung-Ja P.; Barbieri, Joseph T.

    2012-02-07

    Botulinum Neurotoxins (BoNTs) are organized into seven serotypes, A-G. Although several BoNT serotypes enter neurons through synaptic vesicle cycling utilizing dual receptors (a ganglioside and a synaptic vesicle-associated protein), the entry pathway of BoNT/D is less well understood. Although BoNT/D entry is ganglioside-dependent, alignment and structural studies show that BoNT/D lacks key residues within a conserved ganglioside binding pocket that are present in BoNT serotypes A, B, E, F, and G, which indicate that BoNT/D-ganglioside interactions may be unique. In this study BoNT/D is shown to have a unique association with ganglioside relative to the other BoNT serotypes, utilizing a ganglioside binding loop (GBL, residues Tyr-1235-Ala-1245) within the receptor binding domain of BoNT/D (HCR/D) via b-series gangliosides, including GT1b, GD1b, and GD2. HCR/D bound gangliosides and entered neurons dependent upon the aromatic ring of Phe-1240 within the GBL. This is the first BoNT-ganglioside interaction that is mediated by a phenylalanine. In contrast, Trp-1238, located near the N terminus of the ganglioside binding loop, was mostly solvent-inaccessible and appeared to contribute to maintaining the loop structure. BoNT/D entry and intoxication were enhanced by membrane depolarization via synaptic vesicle cycling, where HCR/D colocalized with synaptophysin, a synaptic vesicle marker, but immunoprecipitation experiments did not detect direct association with synaptic vesicle protein 2. Thus, BoNT/D utilizes unique associations with gangliosides and synaptic vesicles to enter neurons, which may facilitate new neurotoxin therapies.

  11. Role of Ce4+ in the scintillation mechanism of codoped Gd3Ga3Al2O12:Ce

    DOE PAGES

    Wu, Yuntao; Meng, Fang; Li, Qi; Koschan, Merry; Melcher, Charles L.

    2014-10-17

    To control the time-response performance of widely used cerium-activated scintillators in cutting-edge medical-imaging devices, such as time-of-flight positron-emission tomography, a comprehensive understanding of the role of Ce valence states, especially stable Ce4+, in the scintillation mechanism is essential. However, despite some progress made recently, an understanding of the physical processes involving Ce4+ is still lacking. The aim of this work is to clarify the role of Ce4+ in scintillators by studying Ca2+ codoped Gd3Ga3Al2O12∶Ce (GGAG∶Ce). By using a combination of optical absorption spectra and x-ray absorption near-edge spectroscopies, the correlation between Ca2+codoping content and the Ce4+ fraction is seen. The energy-levelmore » diagrams of Ce3+ and Ce4+ in the Gd3Ga3Al2O12 host are established by using theoretical and experimental methods, which indicate a higher position of the 5d1 state of Ce4+ in the forbidden gap in comparison to that of Ce3+. Underlying reasons for the decay-time acceleration resulting from Ca2+ codoping are revealed, and the physical processes of the Ce4+-emission model are proposed and further demonstrated by temperature-dependent radioluminescence spectra under x-ray excitation.« less

  12. Luminescence Enhanced Eu(3+)/Gd(3+) Co-Doped Hydroxyapatite Nanocrystals as Imaging Agents In Vitro and In Vivo.

    PubMed

    Xie, Yunfei; He, Wangmei; Li, Fang; Perera, Thalagalage Shalika Harshani; Gan, Lin; Han, Yingchao; Wang, Xinyu; Li, Shipu; Dai, Honglian

    2016-04-27

    Biocompatible, biodegradable, and luminescent nano material can be used as an alternative bioimaging agent for early cancer diagnosis, which is crucial to achieve successful treatment. Hydroxyapatite (HAP) nanocyrstals have good biocompatibility and biodegradability, and can be used as an excellent host for luminescent rare earth elements. In this study, based on the energy transfer from Gd(3+) to Eu(3+), the luminescence enhanced imaging agent of Eu/Gd codoping HAP (HAP:Eu/Gd) nanocrystals are obtained via coprecipitation with plate-like shape and no change in crystal phase composition. The luminescence can be much elevated (up to about 120%) with a nonlinear increase versus Gd doping content, which is due to the energy transfer ((6)PJ of Gd(3+) → (5)HJ of Eu(3+)) under 273 nm and the possible combination effect of the cooperative upconversion and the successive energy transfer under 394 nm, respectively. Results demonstrate that the biocompatible HAP:Eu/Gd nanocrystals can successfully perform cell labeling and in vivo imaging. The intracellular HAP:Eu/Gd nanocrystals display good biodegradability with a cumulative degradation of about 65% after 72 h. This biocompatible, biodegradable, and luminescence enhanced HAP:Eu/Gd nanocrystal has the potential to act as a fluorescent imaging agent in vitro and in vivo. PMID:27043792

  13. [Bi3Fe5O12/Gd3Ga5O12]m magneto-optical photonic crystals

    NASA Astrophysics Data System (ADS)

    Khartsev, S. I.; Grishin, A. M.

    2005-09-01

    A series of one-dimensional heteroepitaxial all-garnet magneto-optical photonic crystals has been synthesized and optically characterized. They are composed of alternating magneto-optically active Bi3Fe5O12 (BIG) and Gd3Ga5O12 (GGG) quarter-wave length layers pulsed laser deposited on to the GGG(001) substrate. Photonic crystals, as designed, exhibit stop band structure and the band gap with the transmittance central peak caused by the light localization in the half-wave length BIG cavity. Compared to previously reported [Bi3Fe5O12/Y3Fe5O12]m photonic crystal [Appl. Phys. Lett. 84, 1438 (2004)], the replacement of optically dense Y3Fe5O12 garnet by transparent Gd3Ga5O12 enables significant enhancement of light rejection within the stop band. Photonic crystals spectra experience "blue" shift in oblique incidence geometry thus demonstrating feasibility to use this effect for tunable magneto-optical filters.

  14. Metal ion blockage of tritium incorporation into gamma-carboxyglutamic acid of prothrombin. Stoichiometry of gamma-carboxyglutamic acid to Gd3+ for the high affinity sites

    SciTech Connect

    Bajaj, S.P.; Saini, R.; Katz, A.; Cai, G.Z.; Maki, S.L.; Brodsky, G.L.

    1988-07-15

    Prothrombin possesses two high affinity and four low affinity gamma-carboxyglutamic acid (Gla)-dependent gadolinium binding sites. Earlier work has shown that tritium can be specifically incorporated at the gamma-carbon of Gla in proteins at pH 5. In the present work we show that inclusion of saturating concentrations of Ca2+ in nondenaturing buffer systems ranging from pH 5.5 to 8.5 prevents the exchange of tritium into all 10 Gla residues of prothrombin. Similarly, saturating concentrations of Gd3+ prevent tritium incorporation into Gla at pH 5.5. Positive cooperativity was observed for the binding of Gd3+ to human prothrombin (at pH 5.5) for the two high affinity sites (Kd congruent to 35 nM). The four low affinity sites bind Gd3+ with a Kd congruent to 5 microM. Incubation of prothrombin ranging in concentrations from 10 to 40 microM with 2 eq of Gd3+ at pH 5.5 prevents 5.7 (average of seven determinations) Gla residues from tritium incorporation. Sedimentation velocity experiments conducted at pH 5.5 indicate that prothrombin in the presence of saturating concentrations of Gd3+ polymerizes, most likely, to a trimer. Further, in the presence of 2 eq of Gd3+, calculated percent weight average concentration of monomer prothrombin is congruent to 100% at 10 microM, approximately equal to 95% at 20 microM, and congruento to 80% at 40 microM protein concentration. Thus, it appears that under conditions in which prothrombin primarily exists as a monomer, occupancy of the initial two metal binding sites by Gd3+ involves six Gla residues.

  15. GM1-ganglioside-induced Abeta assembly on synaptic membranes of cultured neurons.

    PubMed

    Yamamoto, Naoki; Fukata, Yuko; Fukata, Masaki; Yanagisawa, Katsuhiko

    2007-05-01

    The cell-surface expression of GM1 ganglioside was studied using various cultured cells, including brain-derived endothelial cells, astrocytes, neuroblastoma cells (SH-SY5Y), and pheochromocytoma cells (PC12). GM1 ganglioside was detected only on the surface of native and nerve-growth-factor (NGF)-treated PC12 cells. We investigated whether GM1 ganglioside on the surface of these cells is sufficiently potent to induce the assembly of an exogenous soluble amyloid beta-protein (Abeta). A marked Abeta assembly was observed in the culture of NGF-treated PC12 cells. Notably, immunocytochemical study revealed that, despite the ubiquitous surface expression of GM1 ganglioside throughout cell bodies and neurites, Abeta assembly initially occurred at the terminals of SNAP25-immunopositive neurites. Abeta assembly in the culture was completely suppressed by the coincubation of Abeta with the subunit B of cholera toxin, a natural ligand for GM1 ganglioside, or 4396C, a monoclonal antibody specific to GM1-ganglioside-bound Abeta (GAbeta). In primary neuronal cultures, Abeta assembly initially occurred at synaptophysin-positive sites. These results suggest that the cell-surface expression of GM1 ganglioside is strictly cell-type-specific, and that expression of GM1 ganglioside on synaptic membranes is unique in terms of its high potency to induce Abeta assembly through the generation of GAbeta, which is an endogenous seed for Abeta assembly in Alzheimer brain.

  16. Inhibition of enterotoxin from Escherichia coli and Vibrio cholerae by gangliosides from human milk.

    PubMed Central

    Otnaess, A B; Laegreid, A; Ertresvåg, K

    1983-01-01

    Inhibitory activity of enterotoxin from Escherichia coli and Vibrio cholerae was associated with the ganglioside fraction of human milk. Both the milk fat and skim milk contained gangliosides that inhibited the toxins. The most purified milk fraction contained three glycolipid components, of which two migrated close to ganglioside GM1 on thin-layer chromatography plates. A component with a slightly different mobility from GM1 appeared to be associated with the inhibitory activity. Milk ganglioside fraction, derived from 2 ml of human milk, contained 1 to 4 micrograms of lipid-bound sialic acid and completely inhibited 0.1 micrograms of cholera toxin in rabbit intestinal loop experiments. It is suggested that human milk gangliosides, although present only in trace amounts, may be important in protecting infants against enterotoxin-induced diarrhea. PMID:6341242

  17. Gangliosides enhance behavioral and neurochemical effects induced by chronic desipramine (DMI) treatment.

    PubMed

    Molina, V A; Keller, E A; Orsingher, O A

    1989-01-31

    Rats pretreated with gangliosides showed a significant enhancement of the anti-immobility effect of desipramine (DMI) in the forced swimming test. Accordingly, an associated treatment of gangliosides and DMI for 7 days significantly enhanced beta-adrenergic down-regulation in the frontal cortex as compared with the effect of DMI alone. Gangliosides exerted an accelerating effect on the decrease of beta-adrenoceptor density induced by DMI, since the down-regulation phenomenon appeared after 3 days of treatment. Gangliosides did not affect the pharmacokinetics of DMI, since associated acute or prolonged treatments did not modify the brain levels of DMI as compared to the levels of animals that had received DMI alone. These results evidence a stimulating effect of gangliosides on the development of adaptative receptor changes induced by chronic DMI treatment. PMID:2547628

  18. Broadband Yellowish-Green Emitting Ba4Gd3Na3(PO4)6F2:Eu(2+) Phosphor: Structure Refinement, Energy Transfer, and Thermal Stability.

    PubMed

    Fu, Xiaopeng; Lü, Wei; Jiao, Mengmeng; You, Hongpeng

    2016-06-20

    A series of Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphors with a broad emitting band have been synthesized by a traditional solid state reaction. The crystal structural and photoluminescence properties of Ba4Gd3Na3(PO4)6F2:Eu(2+) are investigated. The different crystallographic sites of Eu(2+) in Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphors have been verified by means of their photoluminescence (PL) properties and decay times. Energy transfer between Eu(2+) ions, analyzed by excitation, emission, and PL decay behavior, has been indicated to be a dipole-dipole mechanism. Moreover, the luminescence quantum yield as well as the thermal stability of the Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphor have been investigated systematically. The as-prepared Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphor can act as a promising candidate for n-UV convertible white LEDs. PMID:27249557

  19. Broadband Yellowish-Green Emitting Ba4Gd3Na3(PO4)6F2:Eu(2+) Phosphor: Structure Refinement, Energy Transfer, and Thermal Stability.

    PubMed

    Fu, Xiaopeng; Lü, Wei; Jiao, Mengmeng; You, Hongpeng

    2016-06-20

    A series of Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphors with a broad emitting band have been synthesized by a traditional solid state reaction. The crystal structural and photoluminescence properties of Ba4Gd3Na3(PO4)6F2:Eu(2+) are investigated. The different crystallographic sites of Eu(2+) in Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphors have been verified by means of their photoluminescence (PL) properties and decay times. Energy transfer between Eu(2+) ions, analyzed by excitation, emission, and PL decay behavior, has been indicated to be a dipole-dipole mechanism. Moreover, the luminescence quantum yield as well as the thermal stability of the Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphor have been investigated systematically. The as-prepared Ba4Gd3Na3(PO4)6F2:Eu(2+) phosphor can act as a promising candidate for n-UV convertible white LEDs.

  20. Pathophysiological actions of neuropathy-related anti-ganglioside antibodies at the neuromuscular junction

    PubMed Central

    Plomp, Jaap J; Willison, Hugh J

    2009-01-01

    The outer leaflet of neuronal membranes is highly enriched in gangliosides. Therefore, specific neuronal roles have been attributed to this family of sialylated glycosphingolipids, e.g. in modulation of ion channels and transporters, neuronal interaction and recognition, temperature adaptation, Ca2+ homeostasis, axonal growth, (para)node of Ranvier stability and synaptic transmission. Recent developmental, ageing and injury studies on transgenic mice lacking subsets of gangliosides indicate that gangliosides are involved in maintenance rather than development of the nervous system and that ganglioside family members are able to act in a mutually compensatory manner. Besides having physiological functions, gangliosides are the likely antigenic targets of autoantibodies present in Guillain-Barré syndrome (GBS), a group of neuropathies with clinical symptoms of motor- and/or sensory peripheral nerve dysfunction. Antibody binding to peripheral nerves is thought to either interfere with ganglioside function or activate complement, causing axonal damage and thereby disturbed action potential conduction. The presynaptic motor nerve terminal at the neuromuscular junction (NMJ) may be a prominent target because it is highly enriched in gangliosides and lies outside the blood–nerve barrier, allowing antibody access. The ensuing neuromuscular synaptopathy might contribute to the muscle weakness in GBS patients. Several groups, including our own, have studied the effects of anti-ganglioside antibodies in ex vivo and in vivo experimental settings at mouse NMJs. Here, after providing a background overview on ganglioside synthesis, localization and physiology, we will review those studies, which clearly show that anti-ganglioside antibodies are capable of binding to NMJs and thereby can exert a variety of pathophysiological effects. Furthermore, we will discuss the human clinical electrophysiological and histological evidence produced so far of the existence of a neuromuscular

  1. Study of ferroelectric phase transition in Pb5Ge3O11 by paramagnetic resonance of Gd3+ centres

    NASA Astrophysics Data System (ADS)

    Vazhenin, V. A.; Rumyantsev, E. L.; Artyomov, M. Yu.; Potapov, A. P.

    2016-06-01

    The temperature dependence of the fine structure of trigonal paramagnetic Gd3+ centres in Pb5Ge3O11 was investigated in a wide temperature range in the vicinity of structural phase transition. The temperature dependence of the squared order parameter has been constructed based on the obtained data. It was shown that for the adequate description of its behaviour, the sixth-power term in polarization must be taken into account in the expansion of the thermodynamic potential. The orientational dependence of anomalous broadening of electron paramagnetic resonance signals in the vicinity of ferroelectric phase transition was studied. By comparison of the observed behaviour with the angular dependences of the line width that are characteristic of various broadening mechanisms, it was inferred that it can be attributed to defect induced statistical dispersion of fine structure triclinic parameters.

  2. Mechanochemical preparation of nanocrystalline NaYF4:Gd3+/Yb3+/Tm3+: An efficient upconversion phosphor

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Riesen, Hans

    2015-11-01

    We report on a mechanochemical preparation route for NaYF4:Gd3+/Yb3+/Tm3+ nanoparticles by ball-milling NaF, YF3, GdF3, YbF3 and TmF3 at room temperature. An analysis by XRD and TEM demonstrates that the resulting materials are mainly (∼88% after 4 h ball-milling) in the hexagonal phase and are on the nanoscale with an average crystallite size of ∼20 nm. The prepared nanoparticles display efficient upconversion emission; upon excitation by a 980 nm laser diode, bright visible blue light emission can be observed. However, in accord with previous results, the strongest emission is observed in the NIR at 800 nm.

  3. Highly biocompatible TiO2:Gd3+ nano-contrast agent with enhanced longitudinal relaxivity for targeted cancer imaging

    NASA Astrophysics Data System (ADS)

    Chandran, Parwathy; Sasidharan, Abhilash; Ashokan, Anusha; Menon, Deepthy; Nair, Shantikumar; Koyakutty, Manzoor

    2011-10-01

    We report the development of a novel magnetic nano-contrast agent (nano-CA) based on Gd3+ doped amorphous TiO2 of size ~25 nm, exhibiting enhanced longitudinal relaxivity (r1) and magnetic resonance (MR) contrasting together with excellent biocompatibility. Quantitative T1 mapping of phantom samples using a 1.5 T clinical MR imaging system revealed that the amorphous phase of doped titania has the highest r1 relaxivity which is ~2.5 fold higher than the commercially used CA Magnevist™. The crystalline (anatase) samples formed by air annealing at 250 °C and 500 °C showed significant reduction in r1 values and MR contrast, which is attributed to the loss of proton-exchange contribution from the adsorbed water and atomic re-arrangement of Gd3+ ions in the crystalline host lattice. Nanotoxicity studies including cell viability, plasma membrane integrity, reactive oxygen stress and expression of pro-inflammatory cytokines, performed on human primary endothelial cells (HUVEC), human blood derived peripheral blood mononuclear cells (PBMC) and nasopharyngeal epidermoid carcinoma (KB) cell line showed excellent biocompatibility up to relatively higher doses of 200 μg ml-1. The potential of this nano-CA to cause hemolysis, platelet aggregation and plasma coagulation were studied using human peripheral blood samples and found no adverse effects, illustrating the possibility of the safe intravenous administration of these agents for human applications. Furthermore, the ability of these agents to specifically detect cancer cells by targeting molecular receptors on the cell membrane was demonstrated on folate receptor (FR) positive oral carcinoma (KB) cells, where the folic acid conjugated nano-CA showed receptor specific accumulation on cell membrane while leaving the normal fibroblast cells (L929) unstained. This study reveals that the Gd3+ doped amorphous TiO2 nanoparticles having enhanced magnetic resonance contrast and high biocompatibility is a promising candidate for

  4. Glycolipid and Ganglioside Metabolism Imbalances In Huntington’s Disease

    PubMed Central

    Desplats, Paula A.; Denny, Christine A.; Kass, Kristi E.; Gilmartin, Tim; Head, Steven R.; Sutcliffe, J. Gregor; Seyfried, Thomas N.; Thomas, Elizabeth A.

    2007-01-01

    We have explored genome-wide expression of genes related to glycobiology in exon 1 transgenic Huntington’s disease (HD) mice using a custom designed GLYCOv2 chip and Affymetrix microarray analyses. We validated, using quantitative real-time PCR, abnormal expression levels of genes encoding glycosyltransferases in the striatum of R6/1 transgenic mice, as well as in postmortem caudate from human HD patients. Many of these genes show differential regional expression within the CNS, as indicated by in situ hybridization analysis, suggesting region-specific regulation of this system in the brain. We further show disrupted patterns of glycolipids (acidic and neutral lipids) and/or ganglioside levels in both the forebrain of the R6/1 transgenic mice and caudate samples from human HD subjects. These findings reveal novel disruptions in glycolipid/ganglioside metabolic pathways in the pathology of HD and suggest that the development of new targets to restore glycosphingolipid balance may act to ameliorate some symptoms in HD. PMID:17600724

  5. Changes in Liver Ganglioside Metabolism in Obstructive Cholestasis - the Role of Oxidative Stress.

    PubMed

    Šmíd, V; Petr, T; Váňová, K; Jašprová, J; Šuk, J; Vítek, L; Šmíd, F; Muchová, L

    2016-01-01

    Bile acids have been implicated in cholestatic liver damage, primarily due to their detergent effect on membranes and induction of oxidative stress. Gangliosides can counteract these harmful effects by increasing the rigidity of the cytoplasmic membrane. Induction of haem oxygenase (HMOX) has been shown to protect the liver from increased oxidative stress. The aim of this study was to determine the changes in the synthesis and distribution of liver gangliosides following bile duct ligation (BDL), and to assess the effects of HMOX both on cholestatic liver injury and ganglioside metabolism. Compared to controls, BDL resulted in a significant increase in total as well as complex gangliosides and mRNA expression of corresponding glycosyltransferases ST3GalV, ST8SiaI and B3GalTIV. A marked shift of GM1 ganglioside from the intracellular compartment to the cytoplasmic membrane was observed following BDL. Induction of oxidative stress by HMOX inhibition resulted in a further increase of these changes, while HMOX induction prevented this effect. Compared to BDL alone, HMOX inhibition in combination with BDL significantly increased the amount of bile infarcts, while HMOX activation decreased ductular proliferation. We have demonstrated that cholestasis is accompanied by significant changes in the distribution and synthesis of liver gangliosides. HMOX induction results in attenuation of the cholestatic pattern of liver gangliosides, while HMOX inhibition leads to the opposite effect. PMID:27643580

  6. Receptor ganglioside content of three hosts for Sendai virus. MDBK, HeLa, and MDCK cells.

    PubMed

    Markwell, M A; Fredman, P; Svennerholm, L

    1984-08-01

    Specific gangliosides GD1a, GT1b and GQ1b isolated from brain have been shown to function as receptors for Sendai virus by conferring susceptibility to infection when they are incorporated into receptor-deficient cells (Markwell, M.A.K., Svennerholm, L. and Paulson, J.C. (1981) Proc. Natl. Acad. Sci. USA 78, 5406-5410). The endogenous gangliosides of three commonly used hosts for Sendai virus: MDBK, HeLa, and MDCK cells were analyzed to determine the amount and type of receptor gangliosides present. In all three cell lines, GM3 was the major ganglioside component. The presence of GM1, GD1a and the more complex homologs of the gangliotetraose series was also established. In cell lines derived from normal tissue, MDBK and MDCK cells, gangliosides contributed 47-65% of the total sialic acid. In HeLa cells, gangliosides contributed substantially less (17% of the total sialic acid). The ganglioside content of each cell line was shown not to be immutable but instead to depend on the state of differentiation, passage number, and surface the cells were grown on. Thus, the ganglioside concentration of undifferentiated MDCK cells was found to be substantially greater than that of MDBK or HeLa cells, but decreased as the MDCK cells underwent differentiation. Changes in culture conditions that were shown to decrease the receptor ganglioside content of the cells resulted in a corresponding decrease in susceptibility to infection. The endogenous oligosialogangliosides present in susceptible host cells were shown to function as receptors for Sendai virus.

  7. Recovery from Experimental Parkinsonism in Primates with GM1 Ganglioside Treatment

    NASA Astrophysics Data System (ADS)

    Schneider, J. S.; Pope, Anne; Simpson, Kimberly; Taggart, James; Smith, M. G.; Distefano, L.

    1992-05-01

    A parkinsonian syndrome can be produced in nonhuman primates by administration of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Parkinsonian-like symptoms induced acutely by MPTP were ameliorated after treatment with GM1 ganglioside, a substance shown to have neurotrophic effects on the damaged dopamine system in rodents. Treatment with GM1 ganglioside also increased striatal dopamine and metabolite levels and enhanced the dopaminergic innervation of the striatum as demonstrated by tyrosine hydroxylase immunohistochemistry. These results suggest that GM1 ganglioside may hold promise as a therapeutic agent for the treatment of Parkinson's disease.

  8. Gd3+ spin-lattice relaxation via multi-band conduction electrons in Y(1-x)Gd(x)In3: an electron spin resonance study.

    PubMed

    Cabrera-Baez, M; Iwamoto, W; Magnavita, E T; Osorio-Guillén, J M; Ribeiro, R A; Avila, M A; Rettori, C

    2014-04-30

    Interest in the electronic structure of the intermetallic compound YIn3 has been renewed with the recent discovery of superconductivity at T ∼ 1 K, which may be filamentary in nature. In this work we perform electron spin resonance (ESR) experiments on Gd(3+) doped YIn3 (Y1-xGdxIn3; 0.001 ⪅ x ⩽̸ 0.08), showing that the spin-lattice relaxation of the Gd(3+) ions, due to the exchange interaction between the Gd(3+) localized magnetic moment and the conduction electrons (ce), is processed via the presence of s-, p- and d-type ce at the YIn3 Fermi level. These findings are revealed by the Gd(3+) concentration dependence of the Korringa-like relaxation rate d(ΔH)/dT and g-shift (Δg = g - 1.993), that display bottleneck relaxation behavior for the s-electrons and unbottleneck behavior for the p- and d-electrons. The Korringa-like relaxation rates vary from 22(2) Oe/K for x ⪅ 0.001 to 8(2) Oe/K for x = 0.08 and the g-shift values change, respectively, from a positive Δg = +0.047(10) to a negative Δg = -0.008(4). Analysis in terms of a three-band ce model allows the extraction of the corresponding exchange interaction parameters Jfs, Jfp and Jfd.

  9. Synthesis and Photoluminescence Characteristics of CaIn2O4:Dy3+ Phosphors Co-Doped with Gd3+, Zn2+ or AI3+ Ions.

    PubMed

    Gou, Jing; Wang, Jing; Yu, Binxun; Zhang, Dongyang

    2016-04-01

    Novel warm-white emitting phosphors CaIn2O4:Dy3+ co-doped with Gd3+, Zn2+, or Al3+ ions were prepared by solid state reaction. In this paper, a strategy of co-doping with different ions was used with the aim of affecting the luminescence properties of CaIn204:0.6%Dy3+ under NUV excitation. The luminescence intensities of CaIn2O4:0.6%Dy3+ were enhanced by 0.2% Gd3+ or 0.2% Zn2+ ions co-doping under 367 nm excitation, but lowered by co-doping with 0.2% Al3+ ions. Furthermore, the chromaticity coordinates of CaIn2O4:0.6%Dy3+ can be tuned from the cold-white region to warm-white region with Gd3+ or Zn2+ ions co-doping. These findings show that CaIn2O4:0.6%Dy3+,0.2% Gd3+, and CaIn2O4:0.6%Dy3+,0.2% Zn2+ have potential application value as new warm-white LED phosphors. PMID:27451749

  10. Influence of crystallization in microgravity conditions on the structure and magnetic properties of Gd 3Co and (Gd 0.2Tb 0.8) 3Co compounds

    NASA Astrophysics Data System (ADS)

    Savitsky, E. M.; Torchinova, R. S.; Turanov, S. A.

    1984-04-01

    On board the orbital complex "Salyut-6" during long-term space flight, the experiment on crystallization of the rare earth-cobalt intermetallic compounds of the R 3Co type has been performed. The object of the experiment was to investigate the influence of microgravity on the macro- and microstructure and magnetic properties of Gd 3Co and (Gd 0.2Tb 0.8) 3Co compounds. The experiment included the melting in space of the compounds prepared on Earth under isothermal or thermal gradient conditions and crystallization during passive cooling. The change of meniscus form from the cave form which is characteristic of the ground-based samples to the concave form has been observed for the Gd 3Co flight samples. The Gd 3Co and (Gd 0.2Tb 0.8) 3Co flight samples were characterized with macro- and micropores of the sphere form. By means of vibrating magnetometer the temperature dependences of the magnetization have been measured in the temperature range of 4.2-300 K for Gd 3Co (at 1.7 kOe) and (Gd 0.2Tb 0.8) 3Co (at 500 0e) polyerystal ground-based and flight samples. The temperature dependences of magnetization of both compounds differ significantly compared to those for the ground-based samples in the temperature regions of magnetic ordering.

  11. Changes in brain gangliosides of the neotene and metamorphic (thyroxine-induced) newt axolotl (Ambystoma mexicanum).

    PubMed

    Hilbig, R; Schmitt, M; Rahmann, H

    1987-01-01

    Qualitative and quantitative changes in the concentration of proteins, sialoglycoproteins and gangliosides and in the composition of gangliosides in the brains of the neotene and the thyroxine-induced metamorphic newt axolotl (Ambystoma mexicanum) were investigated. During metamorphosis two polar gangliosides (GT1b and GQ1b) decreased by about 5% each. On the contrary GD1a increased to 10%. Another developmental trend was a slight increase of two other disialogangliosides (GD1b, GD2). Additionally, incorporation profiles (2-8 days) of 14C-N-Ac-mannosamine, the specific precursor for gangliosides, in the brain of neotene and metamorphic axolotls were followed giving evidence of significant changes in the sialoglycoconjugate metabolism of the central nervous system during metamorphosis of this newt.

  12. Configuration and interactions of the polar head group in gangliosides

    PubMed Central

    Maggio, Bruno; Cumar, Federico A.; Caputto, Ranwel

    1980-01-01

    1. The interactions of gangliosides with Ca2+ and some polar-head-group requirements for establishment of particular interactions with phosphatidylcholine were studied in monolayers at the air/145mm-NaCl interface. 2. Ganglioside–Ca2+ interactions, as revealed by surface-potential measurements, depended on the position occupied by sialosyl residues in the oligosaccharide chain. The interactions with Ca2+ of the single sialosyl residue of monosialogangliosides occurred above 0.1mm-CaCl2, whereas the interaction of the cation with additional sialosyl groups in di- or tri-sialogangliosides depended on the carbohydrate residue to which the sialosyl moiety was attached. The sialosyl residue bound in sialosyl–sialosyl linkage interacted very little with Ca2+. The sialosyl residue attached to the terminal galactose of the neutral tetrasaccharide chain interacted with Ca2+ above 1μm-CaCl2. 3. Experiments with mixed monolayers containing dihexadecyl phosphate and hexadecyltrimethylammonium indicated that for the occurrence of interactions of polysialogangliosides with phosphatidylcholine characterized by reductions in molecular packing and surface potential both charged groups of the phospholipid and sialosyl residues with particular dipolar properties in the ganglioside are participating. 4. Possible configurations that can explain the behaviour in monolayers were inspected with space-filling molecular models. The position of the carboxylate group of sialosyl residues with respect to the interface and to the sialosyl molecular plane can explain the different orientation of the dipole-moment vector of this residue, which depends on the position to which it is linked in the oligosaccharide chain. Favoured interactions of polysialogangliosides with phosphatidylcholine may result from a configuration allowing a partial matching of two oppositely oriented electrical vectors contributed by the zwitterionic phosphocholine group and particular sialosyl groups. ImagesPLATE 1

  13. Number of Sialic Acid Residues in Ganglioside Headgroup Affects Interactions with Neighboring Lipids

    PubMed Central

    Frey, Shelli L.; Lee, Ka Yee C.

    2013-01-01

    Monolayers of binary mixtures of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and asialo-(GA1), disialo-(GD1b) and trisialo-(GT1b) gangliosides were used to determine the effect of ganglioside headgroup charge and geometry on its interactions with the neighboring zwitterionic lipid. Surface pressure versus molecular area isotherm measurements along with concurrent fluorescence microscopy of the monolayers at the air-water interface were complemented with atomic force microscopy imaging of monolayers deposited on solid substrates. Results were used to further develop a proposed geometric packing model that the complementary geometry of DPPC and monosialoganglioside GM1 headgroups affects their close molecular packing, inducing condensation of the layer at small mol % of ganglioside. For GA1, GD1b, and GT1b, a similar condensing effect, followed by a fluidizing effect is seen that varies with glycosphingolipid concentration, but results do not directly follow from geometric arguments because less DPPC is needed to condense ganglioside molecules with larger cross-sectional areas. The variations in critical packing mole ratios can be explained by global effects of headgroup charge and resultant dipole moments within the monolayer. Atomic force microscopy micrographs further support the model of ganglioside-induced DPPC condensation with condensed domains composed of a striped phase of condensed DPPC and DPPC/ganglioside geometrically packed complexes at low concentrations. PMID:24047994

  14. Number of sialic acid residues in ganglioside headgroup affects interactions with neighboring lipids.

    PubMed

    Frey, Shelli L; Lee, Ka Yee C

    2013-09-17

    Monolayers of binary mixtures of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and asialo-(GA1), disialo-(GD1b) and trisialo-(GT1b) gangliosides were used to determine the effect of ganglioside headgroup charge and geometry on its interactions with the neighboring zwitterionic lipid. Surface pressure versus molecular area isotherm measurements along with concurrent fluorescence microscopy of the monolayers at the air-water interface were complemented with atomic force microscopy imaging of monolayers deposited on solid substrates. Results were used to further develop a proposed geometric packing model that the complementary geometry of DPPC and monosialoganglioside GM1 headgroups affects their close molecular packing, inducing condensation of the layer at small mol % of ganglioside. For GA1, GD1b, and GT1b, a similar condensing effect, followed by a fluidizing effect is seen that varies with glycosphingolipid concentration, but results do not directly follow from geometric arguments because less DPPC is needed to condense ganglioside molecules with larger cross-sectional areas. The variations in critical packing mole ratios can be explained by global effects of headgroup charge and resultant dipole moments within the monolayer. Atomic force microscopy micrographs further support the model of ganglioside-induced DPPC condensation with condensed domains composed of a striped phase of condensed DPPC and DPPC/ganglioside geometrically packed complexes at low concentrations. PMID:24047994

  15. Impaired Levels of Gangliosides in the Corpus Callosum of Huntington Disease Animal Models

    PubMed Central

    Di Pardo, Alba; Amico, Enrico; Maglione, Vittorio

    2016-01-01

    Huntington Disease (HD) is a genetic neurodegenerative disorder characterized by broad types of cellular and molecular dysfunctions that may affect both neuronal and non-neuronal cell populations. Among all the molecular mechanisms underlying the complex pathogenesis of the disease, alteration of sphingolipids has been identified as one of the most important determinants in the last years. In the present study, besides the purpose of further confirming the evidence of perturbed metabolism of gangliosides GM1, GD1a, and GT1b the most abundant cerebral glycosphingolipids, in the striatal and cortical tissues of HD transgenic mice, we aimed to test the hypothesis that abnormal levels of these lipids may be found also in the corpus callosum white matter, a ganglioside-enriched brain region described being dysfunctional early in the disease. Semi-quantitative analysis of GM1, GD1a, and GT1b content indicated that ganglioside metabolism is a common feature in two different HD animal models (YAC128 and R6/2 mice) and importantly, demonstrated that levels of these gangliosides were significantly reduced in the corpus callosum white matter of both models starting from the early stages of the disease. Besides corroborating the evidence of aberrant ganglioside metabolism in HD, here, we found out for the first time, that ganglioside dysfunction is an early event in HD models and it may potentially represent a critical molecular change influencing the pathogenesis of the disease. PMID:27766070

  16. Linewidth narrowing in the epr spectra of Gd 3+ impurity ions due to the spin-lattice relaxation of lanthanide Kramers' host ions

    NASA Astrophysics Data System (ADS)

    Malhotra, V. M.; Dixon, J. M.; Buckmaster, H. A.

    1980-08-01

    Electron paramagnetic resonance (EPR) of Gd 3+ doped in some lanthanide Kramers' host ion single crytals of the sulfate octahydrates (Ln 2(SO 4) 3·8H 2O;Ln≡Nd,Sm,Dy and Er) and trichloride hexahydrates (LnCl 3·6H 2O;Ln≡Nd, Sm, Dy, Er and Yb) has been studied at T ≅ 297 K using a 9.4 GHz EPR spectrometer. The effect of the Kramers' host Ln 3+ ions on the g-values and linewidths of Gd 3+ spectra has been determined by comparison with those for the isostructural diamagnetic La, Y lattices. At 297 K,in the EPR transitions of Gd 3+ ions have narrow linewidths in spite of the presence of paramagnetic host ions like Nd 3+, Sm 3+ and Yb 3+, whereas an unusual variation in the linewidth is observed in the Dy 3+, Er 3+ hosts as well as a negative g-value shift. In these latter hosts, the linewidths of the Δ M = ± 1 transitions decrease progressively as the magnitude of M increases. The observation of resolved Gd 3+ spectra at 297 K in the above hosts has been interpreted in terms of a random modulation of the interactions between the Gd 3+ and the host Ln 3+ ions by the rapid spin-lattice relaxation of Ln 3+ ions following the generalized theory of magnetic resonance by Kubo and Tomita [15]. τ 1 for Ln 3+ has been estimated in the above mentioned Kramers' hosts from the observed EPR linewidths of Gd 3+ spectra. Values for τ 1 have also been computed for Ln 3+ ions in Ln(C 2H 5SO 4) 3. 9H 2O and LnF 3 from linewidth data in the literature. The results are consistent with an effective host spin-lattice time which is due to Orbach and/or Raman processes, depending upon the temperature and the ground state energy level scheme.

  17. The biological activity of botulinum neurotoxin type C is dependent upon novel types of ganglioside binding sites.

    PubMed

    Strotmeier, Jasmin; Gu, Shenyan; Jutzi, Stephan; Mahrhold, Stefan; Zhou, Jie; Pich, Andreas; Eichner, Timo; Bigalke, Hans; Rummel, Andreas; Jin, Rongsheng; Binz, Thomas

    2011-07-01

    The seven botulinum neurotoxins (BoNT) cause muscle paralysis by selectively cleaving core components of the vesicular fusion machinery. Their extraordinary activity primarily relies on highly specific entry into neurons. Data on BoNT/A, B, E, F and G suggest that entry follows a dual receptor interaction with complex gangliosides via an established ganglioside binding region and a synaptic vesicle protein. Here, we report high resolution crystal structures of the BoNT/C cell binding fragment alone and in complex with sialic acid. The WY-motif characteristic of the established ganglioside binding region was located on an exposed loop. Sialic acid was co-ordinated at a novel position neighbouring the binding pocket for synaptotagmin in BoNT/B and G and the sialic acid binding site in BoNT/D and TeNT respectively. Employing synaptosomes and immobilized gangliosides binding studies with BoNT/C mutants showed that the ganglioside binding WY-loop, the newly identified sialic acid-co-ordinating pocket and the area corresponding to the established ganglioside binding region of other BoNTs are involved in ganglioside interaction. Phrenic nerve hemidiaphragm activity tests employing ganglioside deficient mice furthermore evidenced that the biological activity of BoNT/C depends on ganglioside interaction with at least two binding sites. These data suggest a unique cell binding and entry mechanism for BoNT/C among clostridial neurotoxins. PMID:21542861

  18. Combination of ESI and MALDI mass spectrometry for qualitative, semi-quantitative and in situ analysis of gangliosides in brain

    PubMed Central

    Zhang, Yangyang; Wang, Jun; Liu, Jian’an; Han, Juanjuan; Xiong, Shaoxiang; Yong, Weidong; Zhao, Zhenwen

    2016-01-01

    Gangliosides are a family of complex lipids that are abundant in the brain. There is no doubt the investigations about the distribution of gangliosides in brian and the relationship between gangliosides and Alzheimer’s disease is profound. However, these investigations are full of challenges due to the structural complexity of gangliosides. In this work, the method for efficient extraction and enrichment of gangliosides from brain was established. Moreover, the distribution of gangliosides in brain was obtained by matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI). It was found that 3-aminoquinoline (3-AQ) as matrix was well-suited for MALDI MS analysis of gangliosides in negative ion mode. In addition, the pretreatment by ethanol (EtOH) cleaning brain section and the addition of ammonium formate greatly improved the MS signal of gangliosides in the brain section when MALDI MSI analysis was employed. The distribution of ganliosides in cerebral cortex, hippocampus and cerebellum was respectively acquired by electrospray ionization (ESI) MS and MALDI MSI, and the data were compared for reliability evaluation of MALDI MSI. Further, applying MALDI MSI technology, the distribution of gangliosides in amyloid precursor protein transgenic mouse brain was obtained, which may provide a new insight for bioresearch of Alzheimer’s disease (AD). PMID:27142336

  19. Magnetic behavior of Gd3Ru4Al12, a layered compound with distorted kagomé net

    NASA Astrophysics Data System (ADS)

    Chandragiri, Venkatesh; Iyer, Kartik K.; Sampathkumaran, E. V.

    2016-07-01

    The magnetic behavior of the compound, Gd3Ru4Al12, which was reported about two decades ago to crystallize in a hexagonal structure (space group P63/mmc), has not been investigated in the past literature despite interesting structural features (that is, magnetic layers and triangular as well as kagomé-lattice features favoring frustrated magnetism) characterizing this compound. We report here the results of studies of magnetization, heat capacity and magnetoresistance in the temperature range T  =  1.8–300 K. The results establish that there is a long-range magnetic order of antiferromagnetic type below (T N  =) 18.5 K, despite a much larger value (~80 K) of paramagnetic Curie temperature with a positive sign characteristic of ferromagnetic interaction. We attribute this to geometric frustration. The most interesting finding is that there is an additional magnetic anomaly below ~55 K before the onset of long-range order in the magnetic susceptibility data. Concurrent with this observation, the sign of isothermal change in entropy, ΔS  =  S(0)  ‑  S(H), where H is the externally applied magnetic field, remains positive above T N, with a broad peak. This observation indicates the presence of ferromagnetic clusters before the onset of long-range magnetic order. Thus, this compound may serve as an example of a situation in which magnetic frustration due to geometrical reasons faces competition from such magnetic precursor effects. There is also a reversal of the sign of  ‑ΔS in the curves for lower final fields (H  <  30 kOe) on entering the magnetically ordered state consistent with the entrance to an antiferromagetic state. The magnetoresistance behavior is consistent with the above conclusions.

  20. Magnetic behavior of Gd3Ru4Al12, a layered compound with distorted kagomé net

    NASA Astrophysics Data System (ADS)

    Chandragiri, Venkatesh; Iyer, Kartik K.; Sampathkumaran, E. V.

    2016-07-01

    The magnetic behavior of the compound, Gd3Ru4Al12, which was reported about two decades ago to crystallize in a hexagonal structure (space group P63/mmc), has not been investigated in the past literature despite interesting structural features (that is, magnetic layers and triangular as well as kagomé-lattice features favoring frustrated magnetism) characterizing this compound. We report here the results of studies of magnetization, heat capacity and magnetoresistance in the temperature range T  =  1.8-300 K. The results establish that there is a long-range magnetic order of antiferromagnetic type below (T N  =) 18.5 K, despite a much larger value (~80 K) of paramagnetic Curie temperature with a positive sign characteristic of ferromagnetic interaction. We attribute this to geometric frustration. The most interesting finding is that there is an additional magnetic anomaly below ~55 K before the onset of long-range order in the magnetic susceptibility data. Concurrent with this observation, the sign of isothermal change in entropy, ΔS  =  S(0)  -  S(H), where H is the externally applied magnetic field, remains positive above T N, with a broad peak. This observation indicates the presence of ferromagnetic clusters before the onset of long-range magnetic order. Thus, this compound may serve as an example of a situation in which magnetic frustration due to geometrical reasons faces competition from such magnetic precursor effects. There is also a reversal of the sign of  -ΔS in the curves for lower final fields (H  <  30 kOe) on entering the magnetically ordered state consistent with the entrance to an antiferromagetic state. The magnetoresistance behavior is consistent with the above conclusions.

  1. Gd3+ and Calcium Sensitive, Sodium Leak Currents Are Features of Weak Membrane-Glass Seals in Patch Clamp Recordings

    PubMed Central

    Chemin, Jean; Monteil, Arnaud; Spafford, J. David

    2014-01-01

    The properties of leaky patch currents in whole cell recording of HEK-293T cells were examined as a means to separate these control currents from expressed sodium and calcium leak channel currents from snail NALCN leak channels possessing both sodium (EKEE) and calcium (EEEE) selectivity filters. Leak currents were generated by the weakening of gigaohm patch seals by artificial membrane rupture using the ZAP function on the patch clamp amplifier. Surprisingly, we found that leak currents generated from the weakened membrane/glass seal can be surprisingly stable and exhibit behavior that is consistent with a sodium leak current derived from an expressible channel. Leaky patch currents differing by 10 fold in size were similarly reduced in size when external sodium ions were replaced with the large monovalent ion NMDG+. Leaky patch currents increased when external Ca2+ (1.2 mM) was lowered to 0.1 mM and were inhibited (>40% to >90%) with 10 µM Gd3+, 100 µM La3+, 1 mM Co2+ or 1 mM Cd2+. Leaky patch currents were relatively insensitive (<30%) to 1 mM Ni2+ and exhibited a variable amount of block with 1 mM verapamil and were insensitive to 100 µM mibefradil or 100 µM nifedipine. We hypothesize that the rapid changes in leak current size in response to changing external cations or drugs relates to their influences on the membrane seal adherence and the electro-osmotic flow of mobile cations channeling in crevices of a particular pore size in the interface between the negatively charged patch electrode and the lipid membrane. Observed sodium leak conductance currents in weak patch seals are reproducible between the electrode glass interface with cell membranes, artificial lipid or Sylgard rubber. PMID:24945283

  2. Gd3+ and calcium sensitive, sodium leak currents are features of weak membrane-glass seals in patch clamp recordings.

    PubMed

    Boone, Adrienne N; Senatore, Adriano; Chemin, Jean; Monteil, Arnaud; Spafford, J David

    2014-01-01

    The properties of leaky patch currents in whole cell recording of HEK-293T cells were examined as a means to separate these control currents from expressed sodium and calcium leak channel currents from snail NALCN leak channels possessing both sodium (EKEE) and calcium (EEEE) selectivity filters. Leak currents were generated by the weakening of gigaohm patch seals by artificial membrane rupture using the ZAP function on the patch clamp amplifier. Surprisingly, we found that leak currents generated from the weakened membrane/glass seal can be surprisingly stable and exhibit behavior that is consistent with a sodium leak current derived from an expressible channel. Leaky patch currents differing by 10 fold in size were similarly reduced in size when external sodium ions were replaced with the large monovalent ion NMDG+. Leaky patch currents increased when external Ca2+ (1.2 mM) was lowered to 0.1 mM and were inhibited (>40% to >90%) with 10 µM Gd3+, 100 µM La3+, 1 mM Co2+ or 1 mM Cd2+. Leaky patch currents were relatively insensitive (<30%) to 1 mM Ni2+ and exhibited a variable amount of block with 1 mM verapamil and were insensitive to 100 µM mibefradil or 100 µM nifedipine. We hypothesize that the rapid changes in leak current size in response to changing external cations or drugs relates to their influences on the membrane seal adherence and the electro-osmotic flow of mobile cations channeling in crevices of a particular pore size in the interface between the negatively charged patch electrode and the lipid membrane. Observed sodium leak conductance currents in weak patch seals are reproducible between the electrode glass interface with cell membranes, artificial lipid or Sylgard rubber.

  3. Effects of doping concentration and co-doping with cerium on the luminescence properties of Gd3Ga5O12:Cr3+ for thermometry applications

    NASA Astrophysics Data System (ADS)

    Pareja, Jhon; Litterscheid, Christian; Molina, Alejandro; Albert, Barbara; Kaiser, Bernhard; Dreizler, Andreas

    2015-09-01

    The accuracy of surface temperature measurements using thermographic phosphors relies on an extensive knowledge of the temperature-dependent properties of the phosphor. This paper addresses the effects of doping concentration and co-doping with cerium on the luminescence properties of the Gd3Ga5O12:Cr3+ phosphor. High-crystallinity Gd3Ga5O12:Cr3+,Ce3+ powder samples (GGG:Cr,Ce) with different Cr3+ and Ce3+ concentrations were synthesized, and their luminescence spectra as well as their decay lifetime properties were characterized after UV laser excitation. Results revealed that the concentration quenching decreases the luminescence lifetime at concentrations above 0.5 mol% Cr3+ while the emission spectrum remains independent of the Cr3+ concentration. Co-doping with small amounts of Ce3+ improves the temperature-dependent luminescence characteristics by reducing the afterglow and producing fairly mono-exponential luminescence decays without changing the lifetime.

  4. Lymphokine-activated killer cells targeted by monoclonal antibodies to the disialogangliosides GD2 and GD3 specifically lyse human tumor cells of neuroectodermal origin.

    PubMed

    Honsik, C J; Jung, G; Reisfeld, R A

    1986-10-01

    Monoclonal antibodies 14.18 (IgG3) and 11C64 (IgG3) directed against disialogangliosides GD2 and GD3, respectively, when used in conjunction with human peripheral blood mononuclear cells (PBMCs) stimulated with human recombinant interleukin (rIL-2) lyse both human melanoma and neuroblastoma cells by antibody-dependent cellular cytotoxicity. Such monoclonal antibody-"armed" effector cells are specifically directed to targets expressing the given disialoganglioside without detectable cross-reactivity. In addition, antibody-dependent cellular cytotoxicity as well as the natural killing ability of human PBMCs is augmented by a brief coincubation with rIL-2. PBMCs augmented by rIL-2 and armed with monoclonal antibodies significantly suppressed tumor growth in the xenotransplant nude mouse model. Our results suggest that once a threshold level of activation of PBMCs is achieved, additional rIL-2 (over three orders of magnitude of concentration) does not significantly enhance cytolytic augmentation. Furthermore, anti-GD3 monoclonal antibody 11C64 together with rIL-2-stimulated PBMCs from melanoma patients with widely differing tumor burdens effectively lyse melanoma tumor targets in antibody-dependent cellular cytotoxicity. Our results also suggest that GD2 and GD3 represent distinct and relevant immunotherapeutic target structures on melanoma whereas GD2 does the same for neuroblastoma tumors. Our data suggest that targeting of activated human effector cells may provide a new and effective cancer immunotherapy protocol.

  5. Facile preparation of Gd3+ doped carbon quantum dots: Photoluminescence materials with magnetic resonance response as magnetic resonance/fluorescence bimodal probes

    NASA Astrophysics Data System (ADS)

    Ren, X. Y.; Yuan, X. X.; Wang, Y. P.; Liu, C. L.; Qin, Y.; Guo, L. P.; Liu, L. H.

    2016-07-01

    There are a few bimodal molecular imaging probes constructed by gadolinium (3+) ions in combination with carbon quantum dots (CQDs), and the reported ones show such obvious drawbacks as low luminous efficiency and weak MRI contrast. In the paper, a kind of CQDs photoluminescence materials with magnetic resonance response was prepared by hydrothermal method and employing gadopentetate monomeglumine (GdPM) as a precusor. Here, the GdPM plays a role of not only carbon source, but also gadolinium (3+) sources. When the GdPM aqueous solution with a concentration of 4 mg mL-1 was pyrolyzed under 220 °C and 2.0 MPa for 8 h, an optimal CQDs was obtained which are doped with gadolinium (3+) ions in both chelates and Gd2O3 (named as Gd3+-CQDs). The average diameter of the Gd3+-CQDs is about 1.6 nm, which show a high photoluminescence quantum yield of 7.1%, as well as high longitudinal relaxivity (r1) of 9.87 mM-1 s-1. And owing to the unconspicuous cell toxicity, the Gd3+-CQDs show big possibility for clinical application in magnetic resonance/fluorescence bimodal molecular imaging.

  6. Effect of Mg2+ ions co-doping on timing performance and radiation tolerance of Cerium doped Gd3Al2Ga3O12 crystals

    NASA Astrophysics Data System (ADS)

    Lucchini, M. T.; Babin, V.; Bohacek, P.; Gundacker, S.; Kamada, K.; Nikl, M.; Petrosyan, A.; Yoshikawa, A.; Auffray, E.

    2016-04-01

    Inorganic scintillators with high density and high light yield are of major interest for applications in medical imaging and high energy physics detectors. In this work, the optical and scintillation properties of Mg co-doped Ce:Gd3Al2Ga3O12 crystals, grown using Czochralski technique, have been investigated and compared with Ce:Gd3Al2Ga3O12 ones prepared with identical technology. Improvements in the timing performance of the Mg co-doped samples with respect to Ce:Gd3Al2Ga3O12 ones have been measured, namely a substantial shortening of the rise time and scintillation decay components and lower afterglow were achieved. In particular, a significantly better coincidence time resolution of 233 ps FWHM, being a fundamental parameter for TOF-PET devices, has been observed in Mg co-doped crystals. The samples have also shown a good radiation tolerance under high doses of γ-rays, making them suitable candidates for applications in harsh radiation environments, such as detectors at future collider experiments.

  7. Enhanced UVB emission and analysis of chemical states of Ca5(PO4)3OH:Gd3+,Pr3+ phosphor prepared by co-precipitation

    NASA Astrophysics Data System (ADS)

    Mokoena, P. P.; Nagpure, I. M.; Kumar, Vinay; Kroon, R. E.; Olivier, E. J.; Neethling, J. H.; Swart, H. C.; Ntwaeaborwa, O. M.

    2014-08-01

    Hydroxyapatite (Ca5(PO4)3OH) is a well-known bioceramic material used in medical applications because of its ability to form direct chemical bonds with living tissues. This mineral is currently used as a host for rare-earth ions (e.g. Gd3+, Pr3+, Tb3+, etc.) to prepare phosphors that can be used in light emitting devices of different types. In this study Ca5(PO4)3OH:Gd3+,Pr3+ phosphors were prepared by the co-precipitation method and were characterised by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive x-ray spectroscopy and photoluminescence spectroscopy. The x-ray diffraction pattern was consistent with the hexagonal phase of Ca5(PO4)3OH referenced in JCPDS card number 73-0293. The x-ray photoelectron spectroscopy data indicated that Ca2+ occupied two different lattice sites, referred to as Ca1 and Ca2. The photoluminescence data exhibited a narrowband emission located at 313 nm, which is associated with the 6P7/2→8S7/2 transition of the Gd3+ ion. This emission is classified as ultraviolet B and it is suitable for use in phototherapy lamps to treat various skin diseases. The photoluminescence intensity of the 313 nm emission was enhanced considerably by Pr3+ co-doping.

  8. Lymphokine-activated killer cells targeted by monoclonal antibodies to the disialogangliosides GD2 and GD3 specifically lyse human tumor cells of neuroectodermal origin.

    PubMed Central

    Honsik, C J; Jung, G; Reisfeld, R A

    1986-01-01

    Monoclonal antibodies 14.18 (IgG3) and 11C64 (IgG3) directed against disialogangliosides GD2 and GD3, respectively, when used in conjunction with human peripheral blood mononuclear cells (PBMCs) stimulated with human recombinant interleukin (rIL-2) lyse both human melanoma and neuroblastoma cells by antibody-dependent cellular cytotoxicity. Such monoclonal antibody-"armed" effector cells are specifically directed to targets expressing the given disialoganglioside without detectable cross-reactivity. In addition, antibody-dependent cellular cytotoxicity as well as the natural killing ability of human PBMCs is augmented by a brief coincubation with rIL-2. PBMCs augmented by rIL-2 and armed with monoclonal antibodies significantly suppressed tumor growth in the xenotransplant nude mouse model. Our results suggest that once a threshold level of activation of PBMCs is achieved, additional rIL-2 (over three orders of magnitude of concentration) does not significantly enhance cytolytic augmentation. Furthermore, anti-GD3 monoclonal antibody 11C64 together with rIL-2-stimulated PBMCs from melanoma patients with widely differing tumor burdens effectively lyse melanoma tumor targets in antibody-dependent cellular cytotoxicity. Our results also suggest that GD2 and GD3 represent distinct and relevant immunotherapeutic target structures on melanoma whereas GD2 does the same for neuroblastoma tumors. Our data suggest that targeting of activated human effector cells may provide a new and effective cancer immunotherapy protocol. PMID:3094017

  9. Ultraviolet upconversion enhancement in triply doped NaYF4:Tm3+, Yb3+ particles: The role of Nd3+ or Gd3+ Co-doping

    NASA Astrophysics Data System (ADS)

    Pokhrel, Madhab; Valdes, Carolina; Mao, Yuanbing

    2016-08-01

    Upconversion (UC) particles are currently under intensive investigation, normally for their visible instead of ultraviolet (UV) light luminescence under near-infrared (NIR) irradiation. As a commonly studied host, NaYF4 in particular is known to have low phonon energy and high UC efficiency. Here, we present our work on enhancing UC luminescence in the UV region by adding a third dopant into a binary-doped NaYF4:Yb3+,Tm3+ host. More specifically, neodymium (Nd3+) or gadolinium (Gd3+) ions was co-doped into parent NaYF4:20mol%Yb3+,0.5mol%Tm3+ UC particles to enhance their UV UC luminescence. Experimental results demonstrated that these particles exhibited the highest degree of UV UC enhancements when co-doped with 0.05mol% Nd3+ or 2.0mol% Gd3+, expanding the potential of this type of materials into many possible applications by directly converting NIR irradiation into UV light. Fundamentally, the UV UC emission dependence of these triply doped NaYF4:Yb3+,Tm3+ particles with different Nd3+ and Gd3+ doping concentrations was investigated in terms of ground state absorption, excited state absorption and energy transfer UC mechanisms.

  10. EPR detected polarization transfer between Gd3+ and protons at low temperature and 3.3 T: the first step of dynamic nuclear polarization.

    PubMed

    Nagarajan, Vijayasarathi; Hovav, Yonatan; Feintuch, Akiva; Vega, Shimon; Goldfarb, Daniella

    2010-06-01

    Electron-electron double resonance pulsed electron paramagnetic resonance (EPR) at 95 GHz (3.3 T) is used to follow the dynamics of the electron spin polarization during the first stages of dynamic nuclear polarization in solids. The experiments were performed on a frozen solution of Gd(+3) (S=7/2) in water/glycerol. Focusing on the central vector -1/2 --> vector +1/2 transition we measured the polarization transfer from the Gd(3+) electron spin to the adjacent (1)H protons. The dependence of the echo detected EPR signal on the length of the microwave irradiation at the EPR "forbidden" transition corresponding to an electron and a proton spin flip is measured for different powers, showing dynamics on the microsecond to millisecond time scales. A theoretical model based on the spin density matrix formalism is suggested to account for this dynamics. The central transition of the Gd(3+) ion is considered as an effective S = 1/2 system and is coupled to (1)H (I = 1/2) nuclei. Simulations based on a single electron-single nucleus four level system are shown to deviate from the experimental results and an alternative approach taking into account the more realistic multinuclei picture is shown to agree qualitatively with the experiments.

  11. Detection of Sendai virus receptor, the ganglioside GDla, in target tissue (mouse lung)

    SciTech Connect

    Markwell, M.A.K.; Sato, E.

    1986-05-01

    Previously the authors had shown that the gangliosides GDla, GTlb, and GQlb derived from brain function as receptors for the paramyxovirus Sendai virus by their ability to induce infection when incubated with receptor-deficient cells. Analyses of MDBK, HeLa, and MDCK cells in culture demonstrated that these putative receptors were present in host cells in the quantities required for infection. The primary site of infection for Sendai virus in the whole animal is the respiratory tract, culminating in the lung. Therefore, the ganglioside content of this target organ was analyzed to determine the endogenous receptor population available to Sendai virus. The total ganglioside fraction of lung was resolved into individual species by HPTLC. Gangliosides of the gangliotetraose series were identified by the specific binding of /sup 125/I-labeled tetanus and cholera toxins before and after exposure with sialidase. In this manner one of the major resorcinol-positive bands was identified as GDla. Evidence of the more complex ganglioside receptors for Sendai virus was also seen.

  12. Apprehending ganglioside diversity: a comprehensive methodological approach[S

    PubMed Central

    Masson, Elodie A. Y.; Sibille, Estelle; Martine, Lucy; Chaux-Picquet, Fanny; Bretillon, Lionel; Berdeaux, Olivier

    2015-01-01

    Gangliosides (GGs) make a wide family of glycosphingolipids ubiquitously expressed in mammalian tissues and particularly abundant in the brain and nervous system. They exhibit a huge diversity due to structural variations in both their oligosaccharidic chain and ceramide moiety, which represent a real analytical challenge. Since their discovery in the 1940s, methods have persistently improved until the emergence of LC/MS, which offers a high level of specificity and sensitivity and is suitable with high-throughput profiling studies. We describe here a comprehensive approach relying on various techniques and aiming at fully characterizing GGs in biological samples. First, total GG content was determined by a biochemical assay. Second, GG class composition was assessed by high-performance thin-layer chromatography followed by colorimetric revelation. Then, ceramide types of GG classes were identified, and their relative quantification was performed thanks to the development of a powerful and reliable LC/MS method. Finally, ceramides were structurally characterized, and minor and less common GG classes were identified using high-resolution MS. These methods were applied to the rat retina to provide an exhaustive description of its GG composition, giving the base for a better understanding of the precise roles of GGs in this tissue. PMID:26142958

  13. Influence of tunicamycin, sialidase, and cholera toxin on gangliosides and T-lymphocyte responses to interleukin 2

    SciTech Connect

    Semmes, O.J.; Bailey, J.M.; Merritt, W.D.

    1986-05-01

    The authors have shown that gangliosides inhibit interleukin 2 (IL 2)-dependent proliferation of murine T cells. Tunicamycin (TM), sialidase, and cholera toxin-..beta.. subunit (..beta..-CT) are known modulators of cell surface glycoconjugates. To test the possible role of endogenous gangliosides in T cell responses to IL-2, the effect of these agents on ganglioside expression and cell proliferation was studied. Gangliosides were labelled for 24 hrs with /sup 3/H-glucosamine/galactose in the presence of IL-2 and purified sialidase, TM or ..beta..-CT. Gangliosides were isolated and the species separated by TLC. Alternatively, proliferation was assayed by /sup 3/H-thymidine uptake after 48 hrs culture. TM treatment at a concentration (10 ..mu..g/ml) that completely inhibited proliferation resulted in a 86% reduction of incorporation of saccharide precursors into gangliosides compared to a 50% reduction into proteins. Sialidase treatment (0.1 IU/ml) resulted in a 70% inhibition of proliferation and 30% reduction of radiolabel into gangliosides, of which 3 species were specifically reduced. ..beta..-CT, which binds to GM/sub 1/ and to a lesser extent GD/sub 1a/, caused a 50% reduction in proliferation response at 35 units/ml. The results support the hypothesis that gangliosides are involved in IL-2-dependent proliferation.

  14. Proton NMR study of spin dynamics in the magnetic organic chains M (hfac)3 NITEt (M =Eu3 +,Gd3 + )

    NASA Astrophysics Data System (ADS)

    Mariani, M.; Lascialfari, A.; Caneschi, A.; Ammannato, L.; Gatteschi, D.; Rettori, A.; Pini, M. G.; Cucci, C.; Borsa, F.

    2016-04-01

    In this work, we present a nuclear magnetic resonance (NMR) study of the spin dynamics in the rare-earth-based low-dimensional molecular magnetic chains Eu (hfac) 3NITEt and Gd (hfac) 3NITEt (in short, Eu-Et and Gd-Et). Although both samples are based on the same chemical building block, [(hfac) 3NITEt ] , their magnetic properties change dramatically when the Eu3 + ion, which is nonmagnetic at low temperatures, is substituted by the magnetic Gd3 + ion. The present proton NMR investigation shows that, down to the lowest investigated temperature (T =1.5 K for Gd-Et and T =3 K for Eu-Et), the Eu-Et chain behaves as a one-dimensional Heisenberg model with antiferromagnetic exchange coupling (J =-20 K) between s =1 /2 organic radicals, and has a T -independent exchange frequency (ωe=2.6 ×1012 rad/s). In the Gd-Et chain, in contrast, a competition arises between nearest-neighbor ferromagnetic coupling and next-nearest-neighbor antiferromagnetic coupling; moreover, two phase transitions have previously been found, in agreement with Villain's conjecture: a first transition, at T0=2.2 K, from a high temperature paramagnetic phase to a chiral spin liquid phase, and a second transition, at TN=1.9 K, to a three-dimensional helical spin solid phase. Contrary to the Eu-Et chain (whose three-dimensional ordering temperature is estimated to insurge at very low, TN≈0.3 K), critical spin dynamics effects have been measured in the Gd-Et chain on approaching TN=1.9 K: namely, a divergence of the proton nuclear spin-lattice relaxation rate 1 /T1 , which in turn produces a sudden wipe-out of the NMR signal in a very narrow (Δ T ˜0.04 K) temperature range above TN. Below TN, an inhomogeneous broadening of the NMR line indicates a complete spin freezing. At T0=2.2 K, instead, such critical effects are not observed because NMR measurements probe the two-spin correlation function, while the chiral spin liquid phase transition is associated with a divergence of the four

  15. 5-Methoxysalicylic Acid Matrix for Ganglioside Analysis with Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Lee, Dongkun; Cha, Sangwon

    2015-03-01

    In this note, we report that high quality ganglioside profiles with minimal loss of sialic acid residues can be obtained in the positive ion mode by using a 5-methoxysalicylic acid (MSA) matrix for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Our results showed that MSA produced much less sialic acid losses from gangliosides than DHB, although MSA and DHB are differ only by their functional groups at their 5-positions (-OH for DHB and -OCH3 for MSA). Furthermore, our data also demonstrated that addition of an alkali metal additive was effective for simplifying ganglioside profiles, but not necessary for stabilizing glycosidic bonds of gangliosides if MSA was used as a matrix. This suggests that MALDI MS with MSA has a potential to gain additional benefits from the positive-ion mode analyses without losing performance in ganglioside profiling.

  16. Nondestructive detection of gangliosides with lipophilic fluorochromes and their employment for preparative high-performance thin-layer chromatography.

    PubMed

    Müthing, J; Heitmann, D

    1993-01-01

    A simple and effective procedure for the isolation and purification of gangliosides by preparative thin-layer chromatography is described. The method is based on nondestructive visualization of gangliosides on silica gel-precoated thin-layer chromatography plates by staining with uncharged lipophilic fluorochromes. Fluorescent dyes were added in low concentrations into the mobile phase (0.002%, w/v) without any interference of the ganglioside separation. After uv localization, the fluorescent zones were scraped off the plate and the silica gel was extracted with chloroform/methanol/water (30/60/8). In the following step fluorochromes were removed from gangliosides containing crude extracts by anion-exchange chromatography on DEAE-Sepharose. After desalting, impurities were removed by Iatrobeads chromatography. The method described offers an easy to handle and successful preparative thin-layer chromatography strategy to obtain pure gangliosides in microgram and miligram quantities. PMID:8434781

  17. Cross-Linking Mast Cell Specific Gangliosides Stimulates the Release of Newly Formed Lipid Mediators and Newly Synthesized Cytokines.

    PubMed

    Filho, Edismauro Garcia Freitas; da Silva, Elaine Zayas Marcelino; Zanotto, Camila Ziliotto; Oliver, Constance; Jamur, Maria Célia

    2016-01-01

    Mast cells are immunoregulatory cells that participate in inflammatory processes. Cross-linking mast cell specific GD1b derived gangliosides by mAbAA4 results in partial activation of mast cells without the release of preformed mediators. The present study examines the release of newly formed and newly synthesized mediators following ganglioside cross-linking. Cross-linking the gangliosides with mAbAA4 released the newly formed lipid mediators, prostaglandins D2 and E2, without release of leukotrienes B4 and C4. The effect of cross-linking these gangliosides on the activation of enzymes in the arachidonate cascade was then investigated. Ganglioside cross-linking resulted in phosphorylation of cytosolic phospholipase A2 and increased expression of cyclooxygenase-2. Translocation of 5-lipoxygenase from the cytosol to the nucleus was not induced by ganglioside cross-linking. Cross-linking of GD1b derived gangliosides also resulted in the release of the newly synthesized mediators, interleukin-4, interleukin-6, and TNF-α. The effect of cross-linking the gangliosides on the MAP kinase pathway was then investigated. Cross-linking the gangliosides induced the phosphorylation of ERK1/2, JNK1/2, and p38 as well as activating both NFκB and NFAT in a Syk-dependent manner. Therefore, cross-linking the mast cell specific GD1b derived gangliosides results in the activation of signaling pathways that culminate with the release of newly formed and newly synthesized mediators. PMID:27578923

  18. Cross-Linking Mast Cell Specific Gangliosides Stimulates the Release of Newly Formed Lipid Mediators and Newly Synthesized Cytokines

    PubMed Central

    Zanotto, Camila Ziliotto

    2016-01-01

    Mast cells are immunoregulatory cells that participate in inflammatory processes. Cross-linking mast cell specific GD1b derived gangliosides by mAbAA4 results in partial activation of mast cells without the release of preformed mediators. The present study examines the release of newly formed and newly synthesized mediators following ganglioside cross-linking. Cross-linking the gangliosides with mAbAA4 released the newly formed lipid mediators, prostaglandins D2 and E2, without release of leukotrienes B4 and C4. The effect of cross-linking these gangliosides on the activation of enzymes in the arachidonate cascade was then investigated. Ganglioside cross-linking resulted in phosphorylation of cytosolic phospholipase A2 and increased expression of cyclooxygenase-2. Translocation of 5-lipoxygenase from the cytosol to the nucleus was not induced by ganglioside cross-linking. Cross-linking of GD1b derived gangliosides also resulted in the release of the newly synthesized mediators, interleukin-4, interleukin-6, and TNF-α. The effect of cross-linking the gangliosides on the MAP kinase pathway was then investigated. Cross-linking the gangliosides induced the phosphorylation of ERK1/2, JNK1/2, and p38 as well as activating both NFκB and NFAT in a Syk-dependent manner. Therefore, cross-linking the mast cell specific GD1b derived gangliosides results in the activation of signaling pathways that culminate with the release of newly formed and newly synthesized mediators. PMID:27578923

  19. Differential subcellular localization of cholesterol, gangliosides, and glycosaminoglycans in murine models of mucopolysaccharide storage disorders.

    PubMed

    McGlynn, Robert; Dobrenis, Kostantin; Walkley, Steven U

    2004-12-20

    The mucopolysaccharidoses (MPSs) are a complex family of lysosomal storage disorders characterized by failure to degrade heparan sulfate (HS) and/or other types of glycosaminoglycans (GAGs) secondary to the absence of specific lysosomal enzymes. An accompanying storage of glycosphingolipids (GSLs), most notably GM2 and GM3 gangliosides, has also been documented to occur in many types of MPS disease and is believed to be caused by secondary inhibition of GSL-degradative enzymes by intracellular GAG accumulation. We have documented the presence of secondary ganglioside accumulation in mouse models of several MPS disorders (types I, IIIA, IIIB, and VII) and report that this storage is accompanied by sequestration of free cholesterol in a manner similar to that observed in primary gangliosidoses. Using confocal microscopy, we evaluated the cellular distribution of cholesterol, GM2 and GM3 gangliosides, and HS in brains of mice with MPS IIIA disease. Unexpectedly, we found that although both gangliosides often accumulated in the same neurons, they were consistently located in separate populations of cytoplasmic vesicles. Additionally, GM3 ganglioside only partially co-localized with the primary storage material (HS), and cholesterol likewise only partially co-localized with the GM2 and GM3 gangliosides. These findings raise significant questions about the mechanism(s) responsible for secondary accumulation of storage materials in MPS disease. Furthermore, given that GSLs and cholesterol are constituents of membrane rafts believed critical in signal transduction events in neurons, their co-sequestration in individual neurons suggests the presence of defects in the composition, trafficking, and/or recycling of raft components and thus possible new mechanisms to explain neuronal dysfunction in MPS disorders.

  20. Effect of Gd3+ doping on structural, optical and frequency-dependent dielectric response properties of pseudo-cubic BaTiO3 nanostructures

    NASA Astrophysics Data System (ADS)

    Borah, Manjit; Mohanta, Dambarudhar

    2014-06-01

    We report on the structural, optical and dielectric characterization of solid state derived, pseudo-cubic nanoscale barium titanates (BTs) with gadolinium (Gd3+) as substitutional dopant. Referring to X-ray diffractograms, apart from the BT peaks related to perovskite structure, the non-existence of any additional peaks due to byproducts has revealed that Gd3+ has undergone substitutional doping into the BT host lattice. The well-separated BT nanoparticles of typical size ˜10-15 nm were observed through electron microscopy studies. Following a direct, allowed type carrier transition ( n=1/2), a reduction in the optical band gap value (from 3.28 to 3.255 eV) was observed when the Gd-doping level was varied within 0-7 %. Conversely, the Urbach energy followed an increasing trend, from a value of 0.741 to 1.879 eV. Furthermore, the dielectric constant showed a decreasing tendency with doping content and with increasing frequency. However, in the low-frequency region, the loss tangent (tan δ), which is the combined result of orientational polarization and electrical conduction, was found to be quite high in the doped samples as compared to their un-doped counterpart. The frequency-dependent electrical data were also analyzed in the framework of conductivity and impedance formalisms. In particular, the ac conductivity which varies as ˜ ω s approaches ideal Debye behavior ( s→1) for a low Gd level and a higher doping concentration did not show improved dielectric feature of the host. The incorporation of rare-earth (Gd3+) ions into the BT host system could greatly manifest dielectric relaxation and carrier conduction mechanisms, in a given frequency range, and thus can find immense scope in miniaturized nanoelectronic elements including ceramic capacitors and transducers.

  1. Bingel-Hirsch addition on non-isolated-pentagon-rule Gd3N@C2n (2n = 82 and 84) metallofullerenes: products under kinetic control.

    PubMed

    Alegret, Núria; Salvadó, Patricia; Rodríguez-Fortea, Antonio; Poblet, Josep M

    2013-10-01

    Bingel-Hirsch reactions on fullerenes take place under kinetic control. We here predict, by means of DFT methodology, the products of the Bingel-Hirsch addition on non-isolated-pentagon-rule (non-IPR) metallofullerenes Gd3N@C2n (2n = 82, 84), as modeled by closed-shell Y3N@C2n systems. Adducts on [6,6] B-type bonds placed near the pentalene unit are predicted for the two cages, as found for other non-IPR endohedral fullerenes such as Sc3N@C68.

  2. High-efficiency continuous-wave Nd:Gd3Ga5O12 eye-safe laser operating at 1423.4 nm.

    PubMed

    Zhang, Huanian; Chen, Xiaohan; Wang, Qingpu; Zhang, Xingyu; Chang, Jun; Gao, Liang; Shen, Hongbin; Cong, Zhenhua; Liu, Zhaojun; Tao, Xutang; Li, Ping

    2013-08-01

    A Nd:Gd3Ga5O12 (Nd:GGG) laser operating at a wavelength of 1423.4 nm was demonstrated, which has not yet been reported, and is of great interest for wide application potential. With a pumped power of 18.5 W, a maximum output power of 3.63 W was obtained, corresponding to an optical-to-optical efficiency of 19.6% and a slope efficiency of 26%. These unique characteristics of a Nd:GGG laser at 1423.4 nm thereby open new opportunities for a light source in the field of medicine. PMID:23913067

  3. Dissecting the Role of Anti-ganglioside Antibodies in Guillain-Barré Syndrome: an Animal Model Approach.

    PubMed

    Asthana, Pallavi; Vong, Joaquim Si Long; Kumar, Gajendra; Chang, Raymond Chuen-Chung; Zhang, Gang; Sheikh, Kazim A; Ma, Chi Him Eddie

    2016-09-01

    Guillain-Barré syndrome (GBS) is an autoimmune polyneuropathy disease affecting the peripheral nervous system (PNS). Most of the GBS patients experienced neurological symptoms such as paresthesia, weakness, pain, and areflexia. There are also combinations of non-neurological symptoms which include upper respiratory tract infection and diarrhea. One of the major causes of GBS is due largely to the autoantibodies against gangliosides located on the peripheral nerves. Gangliosides are sialic acid-bearing glycosphingolipids consisting of a ceramide lipid anchor with one or more sialic acids attached to a neutral sugar backbone. Molecular mimicry between the outer components of oligosaccharide of gangliosides on nerve membrane and lipo-oligosaccharide of microbes is thought to trigger the autoimmunity. Intra-peritoneal implantation of monoclonal ganglioside antibodies secreting hybridoma into animals induced peripheral neuropathy. Recent studies demonstrated that injection of synthesized anti-ganglioside antibodies raised by hybridoma cells into mice initiates immune response against peripheral nerves, and eventually failure in peripheral nerve regeneration. Accumulating evidences indicate that the conjugation of anti-ganglioside monoclonal antibodies to activating FcγRIII present on the circulating macrophages inhibits axonal regeneration. The activation of RhoA signaling pathways is also involved in neurite outgrowth inhibition. However, the link between these two molecular events remains unresolved and requires further investigation. Development of anti-ganglioside antagonists can serve as targeted therapy for the treatment of GBS and will open a new approach of drug development with maximum efficacy and specificity.

  4. [Gangliosides as carbohydrate antigens associated with cancer and their possible use in tumor immunotherapy].

    PubMed

    Horwacik, Irena

    2004-01-01

    Aberrant glycosylation is a universal feature of a cancer cell. The examples of such differences are the observed quantitative and qualitative changes in the expression of gangliosides of the tumors of the neuroectodermal origin. The role of gangliosides in cancer progression has been described, as well as their abilities to act as immunosuppressors. The presence of large amounts of these tumor associated carbohydrate antigens (TACA) on cancer cells, as compared to normal cells, opens the possibilities to use them in diagnosis and immunotherapeutic approaches which engage the immune system to fight with a tumor disease. The passive immunotherapy of neuroblastoma with anti-gangliosides monoclonal antibodies and their derivatives has been reviewed. The advantages and the disadvantages of using carbohydrate antigens as vaccines have been summarized. The examples of use of active specific immunotherapy with gangliosides have been described, as well as the approaches to modify the immunogenic potential of these antigens with carbohydrate-protein conjugate vaccines, and antiidiotypic antibodies used with immunomodulators such as QA-21. Finally, in a separate paragraph, the application of anti-carbohydrate antibodies to screen phage display peptide libraries for mimotopes has been described. The perspectives of using carbohydrate mimicking surrogate antigens in the immunotherapy of cancer have been discussed.

  5. Beyond gangliosides: Multiple forms of glycan mimicry exhibited by Campylobacter jejuni in its lipooligosaccharide (LOS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Campylobacter jejuni is well known for synthesizing ganglioside mimics within the glycan component of its lipooligosaccharide (LOS), which have been implicated in triggering Guillain-Barré syndrome (GBS). We now confirm that this pathogen is capable of synthesizing a much broader spectrum of host g...

  6. Ganglioside GT1b protects human spermatozoa from hydrogen peroxide-induced DNA and membrane damage.

    PubMed

    Gavella, Mirjana; Garaj-Vrhovac, Verica; Lipovac, Vaskresenija; Antica, Mariastefania; Gajski, Goran; Car, Nikica

    2010-06-01

    We have reported previously that various gangliosides, the sialic acid containing glycosphingolipids, provide protection against sperm injury caused by reactive oxygen species (ROS). In this study, we investigated the effect of treatment of human spermatozoa with ganglioside GT1b on hydrogen peroxide (H(2)O(2))-induced DNA fragmentation and plasma membrane damage. Single-cell gel electrophoresis (Comet assay) used in the assessment of sperm DNA integrity showed that in vitro supplemented GT1b (100 microm) significantly reduced DNA damage induced by H(2)O(2) (200 microm) (p < 0.05). Measurements of Annexin V binding in combination with the propidium iodide vital dye labelling demonstrated that the spermatozoa pre-treated with GT1b exhibited a significant increase (p < 0.05) in the percentage of live cells with intact membrane and decreased phosphatidylserine translocation after exposure to H(2)O(2). Flow cytometry using the intracellular ROS-sensitive fluorescence dichlorodihydrofluorescein diacetate dye employed to investigate the transport of the extracellularly supplied H(2)O(2) into the cell interior revealed that ganglioside GT1b completely inhibited the passage of H(2)O(2) through the sperm membrane. These results suggest that ganglioside GT1b may protect human spermatozoa from H(2)O(2)-induced damage by rendering sperm membrane more hydrophobic, thus inhibiting the diffusion of H(2)O(2) across the membrane.

  7. Mass spectrometry of gangliosides in extracranial tumors: Application to adrenal neuroblastoma.

    PubMed

    Robu, Adrian C; Vukelić, Željka; Schiopu, Catalin; Capitan, Florina; Zamfir, Alina D

    2016-09-15

    We report here on the introduction of mass spectrometry (MS) for profiling of native gangliosides from an extracranial tumor. The analytical approach was based on a modern platform combining the superior sensitivity and reproducibility of fully automated chip-based nanoelectrospray ionization (nanoESI) with the high resolution and mass accuracy provided by a hybrid quadrupole time-of-flight (QTOF) instrument. The feasibility of the method for the analysis of gangliosides, which are much less expressed in extracranial tissues, was here tested using as the model substrate an adrenal neuroblastoma (NB) specimen located in the abdominal region of a 2-year-old infant. Under properly optimized conditions, MS profiling revealed information on at least 61 different gangliosides exhibiting heterogeneity of the glycan and lipid compositions. NB was found dominated by species bearing short-chain oligosaccharide cores with a reduced overall Neu5Ac content. By chip-nanoESI MS, preceding findings related to the GD2 role in NB were confirmed. Moreover, the screening experiments offered novel information supporting the possible biomarker role of GM4, GM3, and GM1 ganglioside classes. Structural analysis of GM1(d18:1/18:2) and GD1(d18:0/19:0) possibly tumor-associated markers, carried out by tandem MS (MS/MS) using collision-induced dissociation (CID) at low energies, indicated that both GM1a and GD1b isomers are present in NB. PMID:27311552

  8. Structural Basis of GD2 Ganglioside and Mimetic Peptide Recognition by 14G2a Antibody.

    PubMed

    Horwacik, Irena; Golik, Przemyslaw; Grudnik, Przemyslaw; Kolinski, Michal; Zdzalik, Michal; Rokita, Hanna; Dubin, Grzegorz

    2015-10-01

    Monoclonal antibodies targeting GD2 ganglioside (GD2) have recently been approved for the treatment of high risk neuroblastoma and are extensively evaluated in clinics in other indications. This study illustrates how a therapeutic antibody distinguishes between different types of gangliosides present on normal and cancer cells and informs how synthetic peptides can imitate ganglioside in its binding to the antibody. Using high resolution crystal structures we demonstrate that the ganglioside recognition by a model antibody (14G2a) is based primarily on an extended network of direct and water molecule mediated hydrogen bonds. Comparison of the GD2-Fab structure with that of a ligand free antibody reveals an induced fit mechanism of ligand binding. These conclusions are validated by directed mutagenesis and allowed structure guided generation of antibody variant with improved affinity toward GD2. Contrary to the carbohydrate, both evaluated mimetic peptides utilize a "key and lock" interaction mechanism complementing the surface of the antibody binding groove exactly as found in the empty structure. The interaction of both peptides with the Fab relies considerably on hydrophobic contacts however, the detailed connections differ significantly between the peptides. As such, the evaluated peptide carbohydrate mimicry is defined primarily in a functional and not in structural manner. PMID:26179345

  9. Structural Basis of GD2 Ganglioside and Mimetic Peptide Recognition by 14G2a Antibody*

    PubMed Central

    Horwacik, Irena; Golik, Przemyslaw; Grudnik, Przemyslaw; Kolinski, Michal; Zdzalik, Michal; Rokita, Hanna; Dubin, Grzegorz

    2015-01-01

    Monoclonal antibodies targeting GD2 ganglioside (GD2) have recently been approved for the treatment of high risk neuroblastoma and are extensively evaluated in clinics in other indications. This study illustrates how a therapeutic antibody distinguishes between different types of gangliosides present on normal and cancer cells and informs how synthetic peptides can imitate ganglioside in its binding to the antibody. Using high resolution crystal structures we demonstrate that the ganglioside recognition by a model antibody (14G2a) is based primarily on an extended network of direct and water molecule mediated hydrogen bonds. Comparison of the GD2-Fab structure with that of a ligand free antibody reveals an induced fit mechanism of ligand binding. These conclusions are validated by directed mutagenesis and allowed structure guided generation of antibody variant with improved affinity toward GD2. Contrary to the carbohydrate, both evaluated mimetic peptides utilize a “key and lock” interaction mechanism complementing the surface of the antibody binding groove exactly as found in the empty structure. The interaction of both peptides with the Fab relies considerably on hydrophobic contacts however, the detailed connections differ significantly between the peptides. As such, the evaluated peptide carbohydrate mimicry is defined primarily in a functional and not in structural manner. PMID:26179345

  10. Mass spectrometry of gangliosides in extracranial tumors: Application to adrenal neuroblastoma.

    PubMed

    Robu, Adrian C; Vukelić, Željka; Schiopu, Catalin; Capitan, Florina; Zamfir, Alina D

    2016-09-15

    We report here on the introduction of mass spectrometry (MS) for profiling of native gangliosides from an extracranial tumor. The analytical approach was based on a modern platform combining the superior sensitivity and reproducibility of fully automated chip-based nanoelectrospray ionization (nanoESI) with the high resolution and mass accuracy provided by a hybrid quadrupole time-of-flight (QTOF) instrument. The feasibility of the method for the analysis of gangliosides, which are much less expressed in extracranial tissues, was here tested using as the model substrate an adrenal neuroblastoma (NB) specimen located in the abdominal region of a 2-year-old infant. Under properly optimized conditions, MS profiling revealed information on at least 61 different gangliosides exhibiting heterogeneity of the glycan and lipid compositions. NB was found dominated by species bearing short-chain oligosaccharide cores with a reduced overall Neu5Ac content. By chip-nanoESI MS, preceding findings related to the GD2 role in NB were confirmed. Moreover, the screening experiments offered novel information supporting the possible biomarker role of GM4, GM3, and GM1 ganglioside classes. Structural analysis of GM1(d18:1/18:2) and GD1(d18:0/19:0) possibly tumor-associated markers, carried out by tandem MS (MS/MS) using collision-induced dissociation (CID) at low energies, indicated that both GM1a and GD1b isomers are present in NB.

  11. Glycosylated SV2 and Gangliosides as Dual Receptors for Botulinum Neurotoxin Serotype F

    SciTech Connect

    Fu, Zhuji; Chen, Chen; Barbieri, Joseph T.; Kim, Jung-Ja P.; Baldwin, Michael R.

    2010-02-22

    Botulinum neurotoxin causes rapid flaccid paralysis through the inhibition of acetylcholine release at the neuromuscular junction. The seven BoNT serotypes (A-G) have been proposed to bind motor neurons via ganglioside-protein dual receptors. To date, the structure-function properties of BoNT/F host receptor interactions have not been resolved. Here, we report the crystal structures of the receptor binding domains (HCR) of BoNT/A and BoNT/F and the characterization of the dual receptors for BoNT/F. The overall polypeptide fold of HCR/A is essentially identical to the receptor binding domain of the BoNT/A holotoxin, and the structure of HCR/F is very similar to that of HCR/A, except for two regions implicated in neuronal binding. Solid phase array analysis identified two HCR/F binding glycans: ganglioside GD1a and oligosaccharides containing an N-acetyllactosamine core. Using affinity chromatography, HCR/F bound native synaptic vesicle glycoproteins as part of a protein complex. Deglycosylation of glycoproteins using {alpha}(1-3,4)-fucosidase, endo-{beta}-galactosidase, and PNGase F disrupted the interaction with HCR/F, while the binding of HCR/B to its cognate receptor, synaptotagmin I, was unaffected. These data indicate that the HCR/F binds synaptic vesicle glycoproteins through the keratan sulfate moiety of SV2. The interaction of HCR/F with gangliosides was also investigated. HCR/F bound specifically to gangliosides that contain {alpha}2,3-linked sialic acid on the terminal galactose of a neutral saccharide core (binding order GT1b = GD1a GM3; no binding to GD1b and GM1a). Mutations within the putative ganglioside binding pocket of HCR/F decreased binding to gangliosides, synaptic vesicle protein complexes, and primary rat hippocampal neurons. Thus, BoNT/F neuronal discrimination involves the recognition of ganglioside and protein (glycosylated SV2) carbohydrate moieties, providing a structural basis for the high affinity and specificity of BoNT/F for neurons.

  12. New Insights on Non-Enzymatic Oxidation of Ganglioside GM1 Using Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Couto, Daniela; Melo, Tânia; Maciel, Elisabete; Campos, Ana; Alves, Eliana; Guedes, Sofia; Domingues, M. Rosário M.; Domingues, Pedro

    2016-08-01

    Gangliosides are acidic glycosphingolipids that are present in cell membranes and lipid raft domains, being particularly abundant in central nervous systems. They participate in modulating cell membrane properties, cell-cell recognition, cell regulation, and signaling. Disturbance in ganglioside metabolism has been correlated with the development of diseases, such as neurodegenerative diseases, and in inflammation. Both conditions are associated with an increased production of reactive oxidation species (ROS) that can induce changes in the structure of biomolecules, including lipids, leading to the loss or modification of their function. Oxidized phospholipids are usually involved in chronic diseases and inflammation. However, knowledge regarding oxidation of gangliosides is scarce. In order to evaluate the effect of ROS in gangliosides, an in vitro biomimetic model system was used to study the susceptibility of GM1 (Neu5Acα2-3(Galβ1-3GalNAcβ1-4)Galβ1-4Glcβ1Cer) to undergo oxidative modifications. Oxidation of GM1 under Fenton reaction conditions was monitored using high resolution electrospray ionization-mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Upon oxidation, GM1 underwent oxidative cleavages in the carbohydrate chain, leading to the formation of other gangliosides GM2 (GalNAcβ1-4Gal(Neu5Acα2-3)1-4Glcβ1Cer), GM3 (Neu5Acα2-3Galβ1-4Glcβ1Cer), asialo-GM1 (Galβ1-3GalNAcβ1-4Galβ1-4Glcβ1Cer), asialo-GM2 (GalNAcβ1-4Galβ1-4Glcβ1Cer), of the small glycolipids lactosylceramide (LacCer), glucosylceramide (GlcCer), and of ceramide (Cer). In addition, oxygenated GM1 and GM2 (as keto and hydroxy derivatives), glycans, oxidized glycans, and oxidized ceramides were also identified. Nonenzymatic oxidation of GM1 under oxidative stress contributes to the generation of other gangliosides that may participate in the imbalance of gangliosides metabolism in vivo, through uncontrolled enzymatic pathways and, consequently, play some role in

  13. Investigation of cyano-bridged coordination nanoparticles Gd3+/[Fe(CN)6]3-/d-mannitol as T1-weighted MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Perrier, M.; Gallud, A.; Ayadi, A.; Kennouche, S.; Porredon, C.; Gary-Bobo, M.; Larionova, J.; Goze-Bac, Ch.; Zanca, M.; Garcia, M.; Basile, I.; Long, J.; de Lapuente, J.; Borras, M.; Guari, Y.

    2015-07-01

    Cyano-bridged Gd3+/[Fe(CN)6]3- coordination polymer nanoparticles of 3-4 nm stabilized with d-mannitol presenting a high r1 relaxivity value of 11.4 mM-1 s-1 were investigated in vivo as contrast agents (CA) for Magnetic Resonance Imaging (MRI). They allow an increase of the MR image contrast and can act as an efficient intravascular T1 CA with a relatively long blood-circulation lifetime (60 min) without specific toxicity.Cyano-bridged Gd3+/[Fe(CN)6]3- coordination polymer nanoparticles of 3-4 nm stabilized with d-mannitol presenting a high r1 relaxivity value of 11.4 mM-1 s-1 were investigated in vivo as contrast agents (CA) for Magnetic Resonance Imaging (MRI). They allow an increase of the MR image contrast and can act as an efficient intravascular T1 CA with a relatively long blood-circulation lifetime (60 min) without specific toxicity. Electronic supplementary information (ESI) available: Experimental details and procedures, toxicological data, physical characterization. See DOI: 10.1039/c5nr01557j

  14. Charge deformation and orbital hybridization: intrinsic mechanisms on tunable chromaticity of Y3Al5O12:Ce3+ luminescence by doping Gd3+ for warm white LEDs

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Chen, Xiuling; Liu, Fayong; Chen, Haohong; Wang, Hui; Zhao, Erlong; Jiang, Yang; Chan, Ting-Shan; Wang, Chia-Hsin; Zhang, Wenhua; Wang, Yu; Chen, Shifu

    2015-07-01

    The deficiency of Y3Al5O12:Ce (YAG:Ce) luminescence in red component can be compensated by doping Gd3+, thus lead to it being widely used for packaging warm white light-emitting diode devices. This article presents a systematic study on the photoluminescence properties, crystal structures and electronic band structures of (Y1-xGdx)3Al5O12: Ce3+ using powerful experimental techniques of thermally stimulated luminescence, X-ray diffraction, X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and ultraviolet photoelectron spectra (UPS) of the valence band, assisted with theoretical calculations on the band structure, density of states (DOS), and charge deformation density (CDD). A new interpretation from the viewpoint of compression deformation of electron cloud in a rigid structure by combining orbital hybridization with solid-state energy band theory together is put forward to illustrate the intrinsic mechanisms that cause the emission spectral shift, thermal quenching, and luminescence intensity decrease of YAG: Ce upon substitution of Y3+ by Gd3+, which are out of the explanation of the classic configuration coordinate model. The results indicate that in a rigid structure, the charge deformation provides an efficient way to tune chromaticity, but the band gaps and crystal defects must be controlled by comprehensively accounting for luminescence thermal stability and efficiency.

  15. Charge deformation and orbital hybridization: intrinsic mechanisms on tunable chromaticity of Y3Al5O12:Ce3+ luminescence by doping Gd3+ for warm white LEDs.

    PubMed

    Chen, Lei; Chen, Xiuling; Liu, Fayong; Chen, Haohong; Wang, Hui; Zhao, Erlong; Jiang, Yang; Chan, Ting-Shan; Wang, Chia-Hsin; Zhang, Wenhua; Wang, Yu; Chen, Shifu

    2015-01-01

    The deficiency of Y3Al5O12:Ce (YAG:Ce) luminescence in red component can be compensated by doping Gd(3+), thus lead to it being widely used for packaging warm white light-emitting diode devices. This article presents a systematic study on the photoluminescence properties, crystal structures and electronic band structures of (Y1-xGdx)3Al5O12: Ce(3+) using powerful experimental techniques of thermally stimulated luminescence, X-ray diffraction, X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and ultraviolet photoelectron spectra (UPS) of the valence band, assisted with theoretical calculations on the band structure, density of states (DOS), and charge deformation density (CDD). A new interpretation from the viewpoint of compression deformation of electron cloud in a rigid structure by combining orbital hybridization with solid-state energy band theory together is put forward to illustrate the intrinsic mechanisms that cause the emission spectral shift, thermal quenching, and luminescence intensity decrease of YAG: Ce upon substitution of Y(3+) by Gd(3+), which are out of the explanation of the classic configuration coordinate model. The results indicate that in a rigid structure, the charge deformation provides an efficient way to tune chromaticity, but the band gaps and crystal defects must be controlled by comprehensively accounting for luminescence thermal stability and efficiency. PMID:26175141

  16. Ultraviolet-light-emitting AlN:Gd thin-film electroluminescence device using an energy transfer from Gd3+ ions to N2 molecules

    NASA Astrophysics Data System (ADS)

    Toyama, Toshihiko; Ota, Jun; Adachi, Daisuke; Niioka, Yasumasa; Lee, Dong-Hun; Okamoto, Hiroaki

    2009-04-01

    An ultraviolet (UV)-light-emitting AlN:Gd thin-film electroluminescence device (TFELD) was demonstrated for application to flat-panel lighting. AlN:Gd thin films were deposited by rf magnetron sputtering at 200 °C and applied to an ac-voltage-driven TFELD with a double-insulating structure as an emission layer. UV-light emission was observed over a threshold voltage of 270 V for a 5 kHz sinusoidal ac voltage. Electroluminescence (EL) spectra were compared with photoluminescence and cathodoluminescence spectra of AlN:Gd originating from Gd3+ P6j→S87/2 transitions and with an emission spectrum of the second positive system (C3Πu→B3Πg) of N2 molecules. As a result, an energy transfer from Gd3+ P6j→S87/2 to N2 C3Πu→B3Πg is discussed as a likely mechanism for the UV EL. Finally, a preliminary result, associated with the conversion from UV light into blue-green light via a phosphor, is demonstrated for the color tunability of the TFELD.

  17. Charge deformation and orbital hybridization: intrinsic mechanisms on tunable chromaticity of Y3Al5O12:Ce3+ luminescence by doping Gd3+ for warm white LEDs

    PubMed Central

    Chen, Lei; Chen, Xiuling; Liu, Fayong; Chen, Haohong; Wang, Hui; Zhao, Erlong; Jiang, Yang; Chan, Ting-Shan; Wang, Chia-Hsin; Zhang, Wenhua; Wang, Yu; Chen, Shifu

    2015-01-01

    The deficiency of Y3Al5O12:Ce (YAG:Ce) luminescence in red component can be compensated by doping Gd3+, thus lead to it being widely used for packaging warm white light-emitting diode devices. This article presents a systematic study on the photoluminescence properties, crystal structures and electronic band structures of (Y1−xGdx)3Al5O12: Ce3+ using powerful experimental techniques of thermally stimulated luminescence, X-ray diffraction, X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and ultraviolet photoelectron spectra (UPS) of the valence band, assisted with theoretical calculations on the band structure, density of states (DOS), and charge deformation density (CDD). A new interpretation from the viewpoint of compression deformation of electron cloud in a rigid structure by combining orbital hybridization with solid-state energy band theory together is put forward to illustrate the intrinsic mechanisms that cause the emission spectral shift, thermal quenching, and luminescence intensity decrease of YAG: Ce upon substitution of Y3+ by Gd3+, which are out of the explanation of the classic configuration coordinate model. The results indicate that in a rigid structure, the charge deformation provides an efficient way to tune chromaticity, but the band gaps and crystal defects must be controlled by comprehensively accounting for luminescence thermal stability and efficiency. PMID:26175141

  18. Early Supplementation of Phospholipids and Gangliosides Affects Brain and Cognitive Development in Neonatal Piglets123

    PubMed Central

    Liu, Hongnan; Radlowski, Emily C; Conrad, Matthew S; Li, Yao; Dilger, Ryan N; Johnson, Rodney W

    2014-01-01

    Background: Because human breast milk is a rich source of phospholipids and gangliosides and breastfed infants have improved learning compared with formula-fed infants, the importance of dietary phospholipids and gangliosides for brain development is of interest. Objective: We sought to determine the effects of phospholipids and gangliosides on brain and cognitive development. Methods: Male and female piglets from multiple litters were artificially reared and fed formula containing 0% (control), 0.8%, or 2.5% Lacprodan PL-20 (PL-20; Arla Foods Ingredients), a phospholipid/ganglioside supplement, from postnatal day (PD) 2 to PD28. Beginning on PD14, performance in a spatial T-maze task was assessed. At PD28, brain MRI data were acquired and piglets were killed to obtain hippocampal tissue for metabolic profiling. Results: Diet affected maze performance, with piglets that were fed 0.8% and 2.5% PL-20 making fewer errors than control piglets (80% vs. 75% correct on average; P < 0.05) and taking less time to make a choice (3 vs. 5 s/trial; P < 0.01). Mean brain weight was 5% higher for piglets fed 0.8% and 2.5% PL-20 (P < 0.05) than control piglets, and voxel-based morphometry revealed multiple brain areas with greater volumes and more gray and white matter in piglets fed 0.8% and 2.5% PL-20 than in control piglets. Metabolic profiling of hippocampal tissue revealed that multiple phosphatidylcholine-related metabolites were altered by diet. Conclusion: In summary, dietary phospholipids and gangliosides improved spatial learning and affected brain growth and composition in neonatal piglets. PMID:25411030

  19. Selection of novel peptide mimics of the GD2 ganglioside from a constrained phage-displayed peptide library.

    PubMed

    Horwacik, Irena; Czaplicki, Dominik; Talarek, Katarzyna; Kowalczyk, Aleksandra; Bolesta, Elzbieta; Kozbor, Danuta; Rokita, Hanna

    2007-05-01

    Aberrant glycosylation is a universal feature of cancer cells. There are quantitative and qualitative changes in expression of gangliosides observed in tumors of a neuroectodermal origin such as neuroblastoma, melanoma and astrocytoma. The presence of large amounts of GD2 ganglioside on neuroblastoma cells, as compared to normal cells, opens the possibilities to use the tumor-associated carbohydrate antigen in diagnosis and immunotherapeutic approaches. In the quest for immunogens potentially capable of eliciting anti-GD2 ganglioside immune responses, we performed affinity purification of phage-displayed peptides from the LX-8 library (12-mer containing disulphide bridge). The library was screened with the biotinylated anti-GD2 ganglioside 14G2a mAb monoclonal antibody. Our goal was to isolate and characterize peptide mimics of GD2 ganglioside. Numerous individual phage clones that bound 14G2a mAb were identified with the application of immunoblotting technique in the phage pools yielded from the pannings. The phage-borne peptides were tested for their anti-GD2 ganglioside antibody binding ability using ELISA. Among these clones five different phage-displayed peptide sequences were identified. Moreover, we showed that the secondary structure of the peptides, stabilized by the disulfide bridging between cysteine residues at positions 2 and 11, was crucial for the binding of the peptides to 14G2a mAb. In a separate set of experiments, we observed a competition of the peptides, expressed on phages as well as in their synthetic form, with the nominal antigen GD2 ganglioside expressed on IMR-32 neuroblastoma cells for binding to 14G2a mAb. Based on the obtained results we concluded that all of these 5 peptides were mimics of the GD2 ganglioside. PMID:17390090

  20. Specific suppression of major histocompatibility complex class I and class II genes in astrocytes by brain-enriched gangliosides

    PubMed Central

    1993-01-01

    The effect of brain-enriched gangliosides on constitutive and cytokine- inducible expression of major histocompatibility complex (MHC) class I and II genes in cultured astrocytes was studied. Before treatment with gangliosides, astrocytes expressed constitutive MHC class I but not class II molecules, however, the expression of both MHC class I and II cell surface molecules on astrocytes was induced to high levels by interferon gamma (IFN-gamma). Constitutive and IFN-gamma-inducible expression of MHC class I and II molecules was suppressed by treatment of astrocytes with exogenous bovine brain gangliosides in a dose- dependent manner. Constitutive and induced MHC class I and II mRNA levels were also suppressed by gangliosides, indicating control through transcriptional mechanisms. This was consistent with the ability of gangliosides to suppress the binding activity of transcription factors, especially NF-kappa B-like binding activity, important for the expression of both MHC class I and II genes. These studies may be important for understanding mechanisms of central nervous system (CNS)- specific regulation of major histocompatibility molecules in neuroectodermal cells and the role of gangliosides in regulating MHC- restricted antiviral and autoimmune responses within the CNS. PMID:8376939

  1. Relevance of thermal effects in the formation of endohedral metallofullerenes: the case of Gd3N@C(s)(39663)-C82 and other related systems.

    PubMed

    Mulet-Gas, Marc; Rodríguez-Fortea, Antonio; Echegoyen, Luis; Poblet, Josep M

    2013-02-18

    Thermal contributions to the free energy have to be taken into account to rationalize the formation of Gd(3)N@C(s)(39663)-C(82), a nitride endohedral metallofullerene that shows a carbon cage with two fused pentagons which is not predicted to have the lowest electronic energy among the isomers of C(82). The lower symmetry and the larger number of pyracylene units of C(s)(39663)-C(82) with respect to the cage in the lowest-energy metallofullerene, C(2v)(39705)-C(82), favor its formation at high temperatures, as seen for other similar cage isomers that encapsulate metal clusters within the C(80) and C(82) families. These cages, which share common motifs with the prototypical I(h)(7)-C(80), are all related by C(2) insertions/extrusions and Stone-Wales transformations.

  2. Microstructure Evolution and Mechanical Properties of Long Period Stacking Ordered Mg96Gd3Ni1 Alloy with Al and Sr Additions

    NASA Astrophysics Data System (ADS)

    Wang, Dandan; Zhang, Jinshan; Zhang, Wenbo; Nie, Kaibo; Niu, Xiaofeng; You, Zhiyong; Xu, Chunxiang; Wang, Hongxia

    2015-06-01

    The effects of 0.3 at. pct Al and x at. pct Sr ( x = 0.0, 0.1, 0.2, 0.3) on the microstructure and mechanical properties of as-cast Mg96Gd3Ni1 alloy were investigated. With addition of 0.3 at. pct Al, new quaternary Mg-Gd-Ni-Al phases with peculiar rod-like and petal-like morphologies are uniformly distributed in the alloy. The angles between petals of the petal-like phase are all about 60 deg. The microstructure of the alloy is refined, leading to fine grain strengthening. The volume fraction of the long-period stacking ordered phase which is excellent reinforcement phase of Mg alloys increases significantly. Moreover, combined addition of 0.3 at. pct Al and 0.1 at. pct Sr refines the microstructure further and enhances the mechanical properties of the alloy simultaneously.

  3. Structure, microstructure, and magneto-optical properties of laser deposited Bi3Fe5O12/Gd3Ga5O12)(111 films

    NASA Astrophysics Data System (ADS)

    Kahl, S.; Khartsev, S. I.; Grishin, A. M.; Kawano, K.; Kong, G.; Chakalov, R. A.; Abell, J. S.

    2002-06-01

    Bi3Fe5O12 films were deposited onto single crystal Gd3Ga5O12)(111 substrates by pulsed laser deposition. X-ray diffraction patterns and cross sectional transmission electron micrographs show epitaxial film growth and a flat interface between the film and substrate. However, there are small inclusions at the interface and a network of cracks is observed by optical microscope. The refractive index is 3.4 at 800 nm wavelength. The optical transmission is low below 540 nm but increases to 90% for a 1.8 mum thick film at 850 nm. The magneto-optical Faraday rotation is high, with a peak value of -24 deg/mum at 560 nm. The angle of Faraday ellipticity reaches a maximum value of 15 deg/mum at 545 nm.

  4. High-throughput imaging method for direct assessment of GM1 ganglioside levels in mammalian cells

    PubMed Central

    Acosta, Walter; Martin, Reid; Radin, David N.; Cramer, Carole L.

    2016-01-01

    GM1-gangliosidosis is an inherited autosomal recessive disorder caused by mutations in the gene GLB1, which encodes acid β-galactosidase (β-gal). The lack of activity in this lysosomal enzyme leads to accumulation of GM1 gangliosides (GM1) in cells. We have developed a high-content-imaging method to assess GM1 levels in fibroblasts that can be used to evaluate substrate reduction in treated GLB1−/− cells [1]. This assay allows fluorescent quantification in a multi-well system which generates unbiased and statistically significant data. Fluorescently labeled Cholera Toxin B subunit (CTXB), which specifically binds to GM1 gangliosides, was used to detect in situ GM1 levels in a fixed monolayer of fibroblasts. This sensitive, rapid, and inexpensive method facilitates in vitro drug screening in a format that allows a high number of replicates using low working volumes. PMID:26958633

  5. Effects of Ganglioside on Working Memory and the Default Mode Network in Individuals with Subjective Cognitive Impairment: A Randomized Controlled Trial.

    PubMed

    Jeon, Yujin; Kim, Binna; Kim, Jieun E; Kim, Bori R; Ban, Soonhyun; Jeong, Jee Hyang; Kwon, Oran; Rhie, Sandy Jeong; Ahn, Chang-Won; Kim, Jong-Hoon; Jung, Sung Ug; Park, Soo-Hyun; Lyoo, In Kyoon; Yoon, Sujung

    2016-01-01

    This randomized, double-blind, placebo-controlled trial examined whether the administration of ganglioside, an active ingredient of deer bone extract, can improve working memory performance by increasing gray matter volume and functional connectivity in the default mode network (DMN) in individuals with subjective cognitive impairment. Seventy-five individuals with subjective cognitive impairment were chosen to receive either ganglioside (330[Formula: see text][Formula: see text]g/day or 660[Formula: see text][Formula: see text]g/day) or a placebo for 8 weeks. Changes in working memory performance with treatment of either ganglioside or placebo were assessed as cognitive outcome measures. Using voxel-based morphometry and functional connectivity analyses, changes in gray matter volume and functional connectivity in the DMN were also assessed as brain outcome measures. Improvement in working memory performance was greater in the ganglioside group than in the placebo group. The ganglioside group, relative to the placebo group, showed greater increases in gray matter volume and functional connectivity in the DMN. A significant relationship between increased functional connectivity of the precuneus and improved working memory performance was observed in the ganglioside group. The current findings suggest that ganglioside has cognitive-enhancing effects in individuals with subjective cognitive impairment. Ganglioside-induced increases in gray matter volume and functional connectivity in the DMN may partly be responsible for the potential nootropic effects of ganglioside. The clinical trial was registered with ClinicalTrials.gov (identifier: NCT02379481).

  6. Anti-amyloidogenic effects of glycosphingolipid synthesis inhibitors occur independently of ganglioside alterations.

    PubMed

    Noel, Anastasia; Ingrand, Sabrina; Barrier, Laurence

    2016-09-01

    Evidence has suggested that ganglioside abnormalities may be linked to the proteolytic processing of amyloid precursor protein (APP) in Alzheimer's disease (AD) and that pharmacological inhibition of ganglioside synthesis may reduce amyloid β-peptide (Aβ) production. In this study, we assessed the usefulness of two well-established glycosphingolipid (GSL) synthesis inhibitors, the synthetic ceramide analog D-PDMP (1-phenyl 2-decanoylamino-3-morpholino-1-propanol) and the iminosugar N-butyldeoxynojirimycin (NB-DNJ or miglustat), as anti-amyloidogenic drugs in a human cellular model of AD. We found that both GSL inhibitors were able to markedly inhibit Aβ production, although affecting differently the APP cleavage. Surprisingly, the L-enantiomer of PDMP, which promotes ganglioside accumulation, acted similarly to D-PDMP to inhibit Aβ production. Concurrently, both D- and L-PDMP strongly and equally reduced the levels of long-chain ceramides. Altogether, our data suggested that the anti-amyloidogenic effects of PDMP agents are independent of the altered cellular ganglioside composition, but may result, at least in part, from their ability to reduce ceramide levels. Moreover, our current study established for the first time that NB-DNJ, a drug already used as a therapeutic for Gaucher disease (a lysosomal storage disorder), was also able to reduce Aβ production in our cellular model. Therefore, our study provides novel information regarding the possibilities to target amyloidogenic processing of APP through modulation of sphingolipid metabolism and emphasizes the potential of the iminosugar NB-DNJ as a disease modifying therapy for AD. PMID:27373967

  7. Cholera toxin binding affinity and specificity for gangliosides determined by surface plasmon resonance

    SciTech Connect

    Kuziemko, G.M.; Stroh, M.; Stevens, R.C. |

    1996-05-21

    The present study determines the affinity of cholera toxin for the ganglioside series GM1, GM2, GM3, GD1A, GD1B, GT1B, asialo GM1, globotriosyl ceramide, and lactosyl ceramide using real time biospecific interaction analysis (surface plasmon resonance, SPR). SPR shows that cholera toxin preferably binds to gangliosides in the following sequence: GM1 > GM2 > GD1A > GM3 > GT1B > GD1B > asialo-GM1. The measured binding affinity of cholera toxin for the ganglioside sequence ranges from 4.61 {times} 10{sup {minus}12} M for GM1 to 1.88 {times} 10{sup {minus}10} M for asialo GM1. The picomolar values obtained by surface plasmon resonance are similar to K{sub d} values determined with whole-cell binding assays. Both whole-cell assays ans SPR measurements on synthetic membranes are higher than free solution measurements by several orders of magnitude. This difference may be caused by the effects of avidity and charged lipid head-groups, which may play a major role in the binding between cholera toxin, the receptor, and the membrane surface. The primary difference between free solution binding studies and surface plasmon resonance studies is that the latter technique is performed on surfaces resembling the cell membrane. Surface plasmon resonance has the further advantage of measuring apparent kinetic association and dissociation rates in real time, providing direct information about binding events at the membrane surface. 34 refs., 8 figs., 2 tabs.

  8. A Novel Approach for Ganglioside Structural Analysis Based on Electrospray Multiple-Stage Mass Spectrometry

    PubMed Central

    Zamfir, Alina D.; Vukelić, Željka; Schneider, Andrea; Sisu, Eugen; Dinca, Nicolae; Ingendoh, Arnd

    2007-01-01

    A powerful method for detailed structural analysis based on electrospray ionization high-capacity ion-trap multiple-stage mass spectrometry (MS) is for the first time introduced in glycolipidomics. The method was optimized for accurate structural elucidation of human brain gangliosides and specifically applied to normal adult human hippocampus-associated structures. The multiple-stage MS experiments reported here allowed for a complete structural characterization of the oligosaccharide moiety of a GM1 ganglioside species. This was achieved by elucidating the sequence and identification of the GM1a structural isomer from the sialic acid attachment site at the neutral oligosaccharide chain. Moreover, the determination of the d18:1/18:0 sphingoid base/fatty acid composition of the ceramide moiety could be confirmed by this method. The novel protocol developed here proves high potential for rapid, reliable, and reproducible investigation of complex lipid-linked carbohydrates such as polysialylated gangliosides or species carrying some other groups that easily cleave off. PMID:17916791

  9. Imbalance in fatty-acid-chain length of gangliosides triggers Alzheimer amyloid deposition in the precuneus.

    PubMed

    Oikawa, Naoto; Matsubara, Teruhiko; Fukuda, Ryoto; Yasumori, Hanaki; Hatsuta, Hiroyuki; Murayama, Shigeo; Sato, Toshinori; Suzuki, Akemi; Yanagisawa, Katsuhiko

    2015-01-01

    Amyloid deposition, a crucial event of Alzheimer's disease (AD), emerges in distinct brain regions. A key question is what triggers the assembly of the monomeric amyloid ß-protein (Aß) into fibrils in the regions. On the basis of our previous findings that gangliosides facilitate the initiation of Aß assembly at presynaptic neuritic terminals, we investigated how lipids, including gangliosides, cholesterol and sphingomyelin, extracted from synaptic plasma membranes (SPMs) isolated from autopsy brains were involved in the Aß assembly. We focused on two regions of the cerebral cortex; precuneus and calcarine cortex, one of the most vulnerable and one of the most resistant regions to amyloid deposition, respectively. Here, we show that lipids extracted from SPMs isolated from the amyloid-bearing precuneus, but neither the amyloid-free precuneus nor the calcarine cortex, markedly accelerate the Aß assembly in vitro. Through liquid chromatography-mass spectrometry of the lipids, we identified an increase in the ratio of the level of GD1b-ganglioside containing C20:0 fatty acid to that containing C18:0 as a cause of the enhanced Aß assembly in the precuneus. Our results suggest that the local glycolipid environment play a critical role in the initiation of Alzheimer amyloid deposition.

  10. Imbalance in Fatty-Acid-Chain Length of Gangliosides Triggers Alzheimer Amyloid Deposition in the Precuneus

    PubMed Central

    Oikawa, Naoto; Matsubara, Teruhiko; Fukuda, Ryoto; Yasumori, Hanaki; Hatsuta, Hiroyuki; Murayama, Shigeo; Sato, Toshinori; Suzuki, Akemi; Yanagisawa, Katsuhiko

    2015-01-01

    Amyloid deposition, a crucial event of Alzheimer’s disease (AD), emerges in distinct brain regions. A key question is what triggers the assembly of the monomeric amyloid ß-protein (Aß) into fibrils in the regions. On the basis of our previous findings that gangliosides facilitate the initiation of Aß assembly at presynaptic neuritic terminals, we investigated how lipids, including gangliosides, cholesterol and sphingomyelin, extracted from synaptic plasma membranes (SPMs) isolated from autopsy brains were involved in the Aß assembly. We focused on two regions of the cerebral cortex; precuneus and calcarine cortex, one of the most vulnerable and one of the most resistant regions to amyloid deposition, respectively. Here, we show that lipids extracted from SPMs isolated from the amyloid-bearing precuneus, but neither the amyloid-free precuneus nor the calcarine cortex, markedly accelerate the Aß assembly in vitro. Through liquid chromatography-mass spectrometry of the lipids, we identified an increase in the ratio of the level of GD1b-ganglioside containing C20:0 fatty acid to that containing C18:0 as a cause of the enhanced Aß assembly in the precuneus. Our results suggest that the local glycolipid environment play a critical role in the initiation of Alzheimer amyloid deposition. PMID:25798597

  11. Flow cytometric determination of the frequency and heterogeneity of expression of human melanoma-associated antigens.

    PubMed

    Berd, D; Herlyn, M; Koprowski, H; Mastrangelo, M J

    1989-12-01

    We used flow cytometry to measure the expression of human melanoma antigens on cell suspensions dissociated from metastatic masses. The objective was to study the heterogeneity between tumor samples from different patients and between different tumors excised from a single patient. Fifty-three metastases excised from 34 melanoma patients were analyzed with a panel of nine murine monoclonal antibodies (MOABs). Melanoma cells were stained by an indirect fluorescent method and analyzed on a Coulter EPICS C flow cytometer after gating to exclude tumor-infiltrating leukocytes and dead cells. The most consistently and most strongly expressed antigen was the high-molecular-weight proteoglycan (detected by the MOAB 9.2.27), which was expressed on 95% of the melanoma specimens and by a high proportion of cells within each specimen (mean +/- SE, 79.2 +/- 5.5). However, strong expression of this antigen was limited to melanoma cells that had been dissociated mechanically and was markedly diminished by exposure to collagenase. Culture of collagenase-dissociated tumor cells for 24 to 48 h resulted in reexpression of the antigen. The expression of other melanoma-associated antigens was not affected by collagenase treatment, but for these antigens there was more variability between cells from an individual tumor and between tumors from different patients. The percentage of enzyme-dissociated tumors considered positive for MOAB binding (defined as at least 10% of cells positive) and the mean +/- SE of the percentage of positive cells within a tumor were as follows: MOAB ME-9-61 (antigen, p97) = 84% + (41.2 +/- 5.4%); MOAB ME-20.4 (antigen, nerve growth factor receptor) = 40% + (18.7 +/- 5.1%); MOAB ME-24 (antigen, ganglioside GD3) = 84% + (50.8 +/- 4.8%); MOAB ME-311 (antigen, ganglioside 9-O-acetyl-GD3) = 76% + (42.5 +/- 5.1%); MOAB ME-361 (antigen, mainly ganglioside GD2) = 3% + (1.9 +/- 0.8%); MOAB 3F8 (antigen, ganglioside GD2) = 36% (10.5 +/- 3.8%); MOAB 14G2a (antigen

  12. Effect of tin ions on enhancing the intensity of narrow luminescence line at 311 nm of Gd3+ ions in Li2Osbnd PbOsbnd P2O5 glass system

    NASA Astrophysics Data System (ADS)

    Gandhi, Y.; Rajanikanth, P.; Sundara Rao, M.; Ravi Kumar, V.; Veeraiah, N.; Piasecki, M.

    2016-07-01

    This study is mainly focused on enriching the UVB 311 narrow emission band of Gd3+ ions in Li2Osbnd PbOsbnd P2O5 glasses doped with 1.0 mol% of Gd2O3 and mixed with different concentrations of SnO2 (0-7.0 mol%). The emission spectra SnO2 free glasses exhibited intense narrow UVB band at 311 nm due to 6P7/2 → 8S7/2 transition of Gd3+ ions when excited at 273 nm. The intensity of this band is found to be enhanced nearly four times when the glasses are mixed with 3.0 mol% of SnO2. The reasons for this enhancement have been explored in the light of energy transfer from Sn4+ to Gd3+ ions with the help of rate equations. The declustering of Gd3+ ions (that reduce cross relaxation losses) by tin ions is also found to the other reason for such enrichment. The 311 nm radiation is an efficient in the treatment of various skin diseases and currently it is one of the most desirable and commonly utilised UVB in the construction of phototherapy devices.

  13. Effect of tin ions on enhancing the intensity of narrow luminescence line at 311 nm of Gd3+ ions in Li2Osbnd PbOsbnd P2O5 glass system

    NASA Astrophysics Data System (ADS)

    Gandhi, Y.; Rajanikanth, P.; Sundara Rao, M.; Ravi Kumar, V.; Veeraiah, N.; Piasecki, M.

    2016-07-01

    This study is mainly focused on enriching the UVB 311 narrow emission band of Gd3+ ions in Li2Osbnd PbOsbnd P2O5 glasses doped with 1.0 mol% of Gd2O3 and mixed with different concentrations of SnO2 (0-7.0 mol%). The emission spectra SnO2 free glasses exhibited intense narrow UVB band at 311 nm due to 6P7/2 → 8S7/2 transition of Gd3+ ions when excited at 273 nm. The intensity of this band is found to be enhanced nearly four times when the glasses are mixed with 3.0 mol% of SnO2. The reasons for this enhancement have been explored in the light of energy transfer from Sn4+ to Gd3+ ions with the help of rate equations. The declustering of Gd3+ ions (that reduce cross relaxation losses) by tin ions is also found to the other reason for such enrichment. The 311 nm radiation is an efficient in the treatment of various skin diseases and currently it is one of the most desirable and commonly utilised UVB in the construction of phototherapy devices.

  14. Enhancement of the magnetocaloric effect driven by changes in the crystal structure of Al-doped GGG, Gd3Ga5-xAlxO12 (0 ≤x ≤5).

    PubMed

    Sackville Hamilton, A C; Lampronti, G I; Rowley, S E; Dutton, S E

    2014-03-19

    The Gd3Ga5-xAlxO12 (0 ≤ x ≤ 5) solid solution has been prepared using ceramic synthesis routes and the structural and magnetic properties were investigated using x-ray diffraction, magnetic susceptibility, χ, and isothermal magnetisation, M(H), measurements. Our results indicate a contraction of the unit cell and more significant antiferromagnetic interactions as x increases. Despite the decrease in the magnetic polarisation on the application of a field and the corresponding decrease in the change in the magnetic entropy, ΔS, we find that Gd3Al5O12 has a significantly higher observed (17%) and theoretical (14%) ΔS per unit mass than Gd3Ga5O12. The theoretical increase in ΔS per unit volume (7%) is offset by the increased antiferromagnetic interactions in Gd3Al5O12. The differences in ΔS are driven by a decrease in both the mass and the density as Al ions replace Ga ions. These results highlight the importance of changes to the crystal structure when considering materials for solid state magnetic cooling. PMID:24590065

  15. Gangliosides are functional nerve cell ligands for myelin-associated glycoprotein (MAG), an inhibitor of nerve regeneration

    PubMed Central

    Vyas, Alka A.; Patel, Himatkumar V.; Fromholt, Susan E.; Heffer-Lauc, Marija; Vyas, Kavita A.; Dang, Jiyoung; Schachner, Melitta; Schnaar, Ronald L.

    2002-01-01

    Myelin-associated glycoprotein (MAG) binds to the nerve cell surface and inhibits nerve regeneration. The nerve cell surface ligand(s) for MAG are not established, although sialic acid-bearing glycans have been implicated. We identify the nerve cell surface gangliosides GD1a and GT1b as specific functional ligands for MAG-mediated inhibition of neurite outgrowth from primary rat cerebellar granule neurons. MAG-mediated neurite outgrowth inhibition is attenuated by (i) neuraminidase treatment of the neurons; (ii) blocking neuronal ganglioside biosynthesis; (iii) genetically modifying the terminal structures of nerve cell surface gangliosides; and (iv) adding highly specific IgG-class antiganglioside mAbs. Furthermore, neurite outgrowth inhibition is mimicked by highly multivalent clustering of GD1a or GT1b by using precomplexed antiganglioside Abs. These data implicate the nerve cell surface gangliosides GD1a and GT1b as functional MAG ligands and suggest that the first step in MAG inhibition is multivalent ganglioside clustering. PMID:12060784

  16. Constituents of ophiuroidea. 1. Isolation and structure of three ganglioside molecular species from the brittle star Ophiocoma scolopendrina.

    PubMed

    Inagaki, M; Shibai, M; Isobe, R; Higuchi, R

    2001-12-01

    Three ganglioside molecular species, OSG-0 (1), OSG-1 (2), and OSG-2 (3) have been obtained from the polar lipid fraction of the chloroform/methanol extract of the brittle star Ophiocoma scolopendrina. The structures of these gangliosides have been determined on the basis of chemical and spectroscopic evidence as 1-O-[(N-glycolyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (1), 1-O-[8-O-sulfo-(N-acetyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyll-ceramide (2) and 1-O-[(N-glycolyl-alpha-D-neuraminosyl)-(2-->8)-(N-acetyl- and N-glycolyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (3). The ceramide moieties were composed of heterogeneous unsubstituted fatty acid, 2-hydroxy fatty acid and phytosphingosine units. Compounds 2 and 3 represent new ganglioside molecular species. PMID:11767069

  17. Constituents of ophiuroidea. 1. Isolation and structure of three ganglioside molecular species from the brittle star Ophiocoma scolopendrina.

    PubMed

    Inagaki, M; Shibai, M; Isobe, R; Higuchi, R

    2001-12-01

    Three ganglioside molecular species, OSG-0 (1), OSG-1 (2), and OSG-2 (3) have been obtained from the polar lipid fraction of the chloroform/methanol extract of the brittle star Ophiocoma scolopendrina. The structures of these gangliosides have been determined on the basis of chemical and spectroscopic evidence as 1-O-[(N-glycolyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (1), 1-O-[8-O-sulfo-(N-acetyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyll-ceramide (2) and 1-O-[(N-glycolyl-alpha-D-neuraminosyl)-(2-->8)-(N-acetyl- and N-glycolyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (3). The ceramide moieties were composed of heterogeneous unsubstituted fatty acid, 2-hydroxy fatty acid and phytosphingosine units. Compounds 2 and 3 represent new ganglioside molecular species.

  18. Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals

    PubMed Central

    Ozaki, N.; Nellis, W. J.; Mashimo, T.; Ramzan, M.; Ahuja, R.; Kaewmaraya, T.; Kimura, T.; Knudson, M.; Miyanishi, K.; Sakawa, Y.; Sano, T.; Kodama, R.

    2016-01-01

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallic conductivity (MMC). These results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. The systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions. PMID:27193942

  19. Influence of Pressure and Temperature on Microstructure and Mechanical Behavior of Squeeze Cast Mg-10Gd-3Y-0.5Zr Alloy

    NASA Astrophysics Data System (ADS)

    Wang, Cunlong; Lavernia, Enrique J.; Wu, Guohua; Liu, Wencai; Ding, Wenjiang

    2016-08-01

    The influence of applied pressure and pouring temperature on the microstructure and mechanical properties of a squeeze cast (SC) Mg-10Gd-3Y-0.5Zr (GW103K) alloy was systematically investigated. Our results show that increasing the applied pressure leads to microstructure refinement of the GW103K alloy with accompanying enhancement of tensile yield strength (TYS), ultimate tensile strength (UTS), and elongation to failure ( E f); a decrease in pouring temperature also leads to grain refinement and increases of TYS while decreasing the UTS and E f. Our results show that, for the range of parameters studied herein, an applied pressure of ~160 MPa, in combination with a pouring temperature of ~993 K (720 °C), represents optimum process parameters for squeeze casting of GW103K. Using these process parameters, the TYS, UTS, and E f of squeeze cast GW103K alloy are 151 MPa, 232 MPa, and 3.0 pct in the as-cast state, and 264 MPa, 383 MPa, and 1.5 pct, respectively, in the as-T6 heat-treated state, both of which represent significant improvements over those of the gravity cast (GC) counterpart material.

  20. Real-time tracking of dissociation of hyperpolarized 89Y-DTPA: a model for degradation of open-chain Gd3+ MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Ferguson, Sarah; Niedbalski, Peter; Parish, Christopher; Kiswandhi, Andhika; Kovacs, Zoltan; Lumata, Lloyd

    Gadolinium (Gd) complexes are widely used relaxation-based clinical contrast agents in magnetic resonance imaging (MRI). Gd-based MRI contrast agents with open-chain ligand such as Gd-DTPA, commercially known as magnevist, are less stable compared to Gd complexes with macrocyclic ligands such as GdDOTA (Dotarem). The dissociation of Gd-DPTA into Gd ion and DTPA ligand under certain biological conditions such as high zinc levels can potentially cause kidney damage. Since Gd is paramagnetic, direct NMR detection of the Gd-DTPA dissociation is quite challenging due to ultra-short relaxation times. In this work, we have investigated Y-DTPA as a model for Gd-DPTA dissociation under high zinc content solutions. Using dissolution dynamic nuclear polarization (DNP), the 89Y NMR signal is amplified by several thousand-fold. Due to the the relatively long T1 relaxation time of 89Y which translates to hyperpolarization lifetime of several minutes, the dissociation of Y-DTPA can be tracked in real-time by hyperpolarized 89Y NMR spectroscopy. Dissociation kinetic rates and implications on the degradation of open-chain Gd3+ MRI contrast agents will be discussed. This work was supported by the U.S. Department of Defense Award Number W81XWH-14-1-0048 and by the Robert A. Welch Foundation research Grant Number AT-1877.

  1. A Eu(3+)/Gd(3+)-EDTA-doped structurally controllable hollow mesoporous carbon for improving the oral bioavailability of insoluble drugs and in vivo tracing.

    PubMed

    Liu, Jia; Zhao, Yating; Cui, Yu; Yue, Yang; Gao, Yikun; Zhao, Qinfu; Liu, Jie; Wang, Siling

    2016-08-01

    A structurally controllable fluorescence-labeled hollow mesoporous carbon (HMC) was simply prepared to improve the oral bioavailability of insoluble drugs and further trace their delivery process in vivo. The hollow structure was derived from an inverse replica process using mesoporous silica as a template and the fluorescent label was prepared by doping the carboxylated HMC with a confinement of Eu(3+)/Gd(3+)-EDTA. The physicochemical properties of the composites were systematically characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectra tests prior to studying their effects on drug-release behavior and biodistribution. As a result, the thickness of the carrier's shell was adjusted from 70 nm to 130 nm and the maximum drug loading was up to 73.6%. The model drug carvedilol (CAR) showed sustained release behavior compared to CAR commercial capsules, and the dissolution rate slowed down as the shells got thicker. AUC0-48h and Tmax were enlarged 2.2 and 6.5 fold, respectively, which demonstrated that oral bioavailability was successfully improved. Bioimaging tests showed that the novel carbon vehicle had a long residence time in the gastrointestinal tract. In short, the newly designed HMC is a promising drug carrier for both oral bioavailability improvement and in vivo tracing. PMID:27334550

  2. Radiation-induced electrical conductivity in MgO, Al2O3, and Gd3Ga5O12 single crystals

    NASA Astrophysics Data System (ADS)

    Ulmanis, Uldis

    1997-02-01

    The radiation-induced electrical conductivity (RIC) of single crystals MgO, Al2 O3 and Gd3Ga5O12 (GGG) has been measured during gamma-neutron irradiation at dose rates between 102 and 106 Gy/h and temperature from 20 to 400 degrees Celsius. The RIC for these crystals varied in a linear manner with dose rate in temperature region 60 - 300 degrees Celsius. The activation energy of conductivity before irradiation above 230 degrees Celsius is 1.4 eV for MgO, 0.75 eV for Al2O3 and 0.57 eV for GGG. The activation energy decrease during irradiation and at high dose rates (greater than 105 Gy/h) electrical conductivity does not depend on temperature. Single crystal MgO irradiation at 320 degrees Celsius and dose rate 500 kGy/h in electrical field 10 kV/m shows no noticeable radiation-induced electrical degradation (RIED).

  3. The state of Gd3+ ions in sulfo-and sulfophenol-containing ion exchange polymers according to the EPR data

    NASA Astrophysics Data System (ADS)

    Vishnevskaya, G. P.; Frolova, E. N.; Konstantinov, V. N.; Fakhrutdinov, A. R.

    2007-12-01

    The KU-2 and KU-1 universal cationites were found to exhibit partly selective properties with respect to Gd3+ ions. As distinct from the transition group cations studied earlier, gadolinium ions formed centers with SO{3/-} functional groups even in sulfo resin matrices hydrated to the greatest extent, and the fraction of these complexes increased as free water was removed from ionite matrices. The EPR spectra of gadolinium aquacomplexes in hydrated polymers were similar to their spectra in aqueous solutions. The strong crystal field condition ( D[Figure not available: see fulltext.] hv) with the presence of axial and rhombic components was fulfilled for fixed complexes. The spectra corresponded to complexes of two types. The effective g-factors and λ = E/D parameters were calculated to describe the spectra of systems with spin S = 7/2 quantitatively. The correlation times of rotational motion of aquacomplexes in hydrated cationites were determined. These times were found to be longer (1.5 to 3 times) than in aqueous solutions. Dipole-dipole interactions between gadolinium ions were studied to estimate the local concentrations of sorbed ions in large-sized pores.

  4. A Eu3+/Gd3+-EDTA-doped structurally controllable hollow mesoporous carbon for improving the oral bioavailability of insoluble drugs and in vivo tracing

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Zhao, Yating; Cui, Yu; Yue, Yang; Gao, Yikun; Zhao, Qinfu; Liu, Jie; Wang, Siling

    2016-08-01

    A structurally controllable fluorescence-labeled hollow mesoporous carbon (HMC) was simply prepared to improve the oral bioavailability of insoluble drugs and further trace their delivery process in vivo. The hollow structure was derived from an inverse replica process using mesoporous silica as a template and the fluorescent label was prepared by doping the carboxylated HMC with a confinement of Eu3+/Gd3+-EDTA. The physicochemical properties of the composites were systematically characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectra tests prior to studying their effects on drug-release behavior and biodistribution. As a result, the thickness of the carrier’s shell was adjusted from 70 nm to 130 nm and the maximum drug loading was up to 73.6%. The model drug carvedilol (CAR) showed sustained release behavior compared to CAR commercial capsules, and the dissolution rate slowed down as the shells got thicker. AUC0-48h and Tmax were enlarged 2.2 and 6.5 fold, respectively, which demonstrated that oral bioavailability was successfully improved. Bioimaging tests showed that the novel carbon vehicle had a long residence time in the gastrointestinal tract. In short, the newly designed HMC is a promising drug carrier for both oral bioavailability improvement and in vivo tracing.

  5. Angular dependant micro-ESR characterization of a locally doped Gd3+:Al2O3 hybrid system for quantum applications

    NASA Astrophysics Data System (ADS)

    Wisby, I. S.; de Graaf, S. E.; Gwilliam, R.; Adamyan, A.; Kubatkin, S. E.; Meeson, P. J.; Tzalenchuk, A. Ya.; Lindstrom, T.

    Rare-earth doped crystals interfaced with superconducting quantum circuitry are an attractive platform for quantum memory and transducer applications. Here we present a detailed characterization of a locally implanted Gd3+ in Al2O3 system coupled to a superconducting micro-resonator, by performing angular dependent micro-electron-spin-resonance (micro-ESR) measurements at mK temperatures. The device is fabricated using a hard Si3N4 mask to facilitate a local ion-implantation technique for precision control of the dopant location. The technique is found not to degrade the internal quality factor of the resonators which remains above 105 (1). We find the measured angular dependence of the micro-ESR spectra to be in excellent agreement with the modelled Hamiltonian, supporting the conclusion that the dopant ions are successfully integrated into their relevant lattice sites whilst maintaining crystalline symmetries. Furthermore, we observe clear contributions from individual microwave field components of our micro-resonator, emphasising the need for controllable local implantation. 1 Wisby et al. Appl. Phys. Lett. 105, 102601 (2014)

  6. Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals.

    PubMed

    Ozaki, N; Nellis, W J; Mashimo, T; Ramzan, M; Ahuja, R; Kaewmaraya, T; Kimura, T; Knudson, M; Miyanishi, K; Sakawa, Y; Sano, T; Kodama, R

    2016-01-01

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallic conductivity (MMC). These results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. The systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions. PMID:27193942

  7. Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals

    NASA Astrophysics Data System (ADS)

    Ozaki, N.; Nellis, W. J.; Mashimo, T.; Ramzan, M.; Ahuja, R.; Kaewmaraya, T.; Kimura, T.; Knudson, M.; Miyanishi, K.; Sakawa, Y.; Sano, T.; Kodama, R.

    2016-05-01

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallic conductivity (MMC). These results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. The systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions.

  8. Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals

    DOE PAGES

    Ozaki, N.; Nellis, W. J.; Mashimo, T.; Ramzan, M.; Ahuja, R.; Kaewmaraya, T.; Kimura, T.; Knudson, M.; Miyanishi, K.; Sakawa, Y.; et al

    2016-05-19

    Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallic conductivity (MMC). Thesemore » results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. Lastly, the systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions.« less

  9. Spin-phonon and lattice contributions to the ground-state splitting of Gd3+ and Eu2+ in scheelite crystals

    NASA Astrophysics Data System (ADS)

    Gorlov, A. D.

    2015-07-01

    The EPR spectra of Gd3+ in CaWO4 single crystals have been studied at temperatures T = 1.8, 4.2, and 114-300 K, and the temperature dependence of the parameters b {/n m } ( T) of the spin Hamiltonian has been found. The behavior of b {2/0}( T) has been analyzed. The spin-phonon and static lattice contributions b {2/0}( F) and b {2/0}( L) to b {2/0}( T) have been revealed. For this purpose, the variation of b {2/0}( L) has been calculated taking into account the thermal shifts of oxygen ions in CaWO4. Similar analysis has been carried out for CaWO4: Eu2+ based on the EPR data of other authors (Bronstein, Voterra and Harvey, Kiefte). It has been shown that at b {2/0}( F) > 0, the variation of b {2/0}( F) as a function of T for these impurity centers is described well by the Pfister model and a sign change of b {2/0}( T) for Eu2+ is determined by thermal expansion of the lattice.

  10. Continuous wave and passively Q-switched laser performance of Nd:LuxGd3-xGa5O12 crystal at 1062 nm

    NASA Astrophysics Data System (ADS)

    Fu, X. W.; Jia, Z. T.; Yang, H.; Li, Y. B.; Yuan, D. S.; Zhang, B. T.; Dong, C. M.; He, J. L.; Tao, X. T.

    2012-12-01

    Continuous wave (CW) and passively Q-switched (PQS) laser properties at 1062 nm of the Nd:LuxGd3-xGa5O12 (Nd:LGGG) disordered crystal have been demonstrated. The doping concentrations of Nd3+ and Lu3+ in the as obtained crystal were measured to be 0.96 and 0.66 at.%, respectively. In the CW regime, the output power of 9.73 W was obtained with an optical-to-optical efficiency as high as 60.7% and slope efficiency of 61.2%. During the passively Q-switched operation, the maximum output power of 1.24 W was achieved under the absorbed pump power of 6.86 W. The maximum peak power of 14.20 kW and single pulse energy of 148 μJ were obtained with the Toc = 10% under the absorbed pump power of 6.36 W. The results are much better than those obtained with Nd:LGGG crystal doped with 13.6 at.% Lu3+ and 0.53 at.% Nd3+ ions.

  11. Low field driven latching-type Bi3Fe5O12/Gd3Ga5O12 magneto-optical display

    NASA Astrophysics Data System (ADS)

    Grishin, A. M.; Khartsev, S. I.; Bonetti, S.

    2006-06-01

    Series of heteroepitaxial all-garnet magneto-optical (MO) Bi3Fe5O12n/Gd3Ga5O12m (BIGn/GGGm, n =1, 2, 3, 4, 5 and m =1 and 2 are the numbers of unit cells) nanostructured multilayers have been sintered by pulsed laser deposition technique. Processing parameters and structure of grown films have been optimized to obtain perpendicular magnetic anisotropy and square hysteresis loop with low coercive and saturation magnetic fields. Regular alternating of lattice mismatched BIG and GGG atomic layers inhibited nucleation of misfit dislocations; thus a long range coherent compressive strain was preserved through the whole thickness of BIGn/GGGm multilayer stack. 2.5μm thick BIG3/GGG2 sample (1200 BIG and 800 GGG unit cells) at λ =678nm shows MO Faraday rotation ΘF=±1.4°, transmittance of 82%, attenuation α =3400dB/cm, squareness of magnetization loop (remnant-to-saturation magnetizations ratio) as high as 92%, and saturation and coercive fields as low as 56 and 25Oe, respectively. MO remanence (latching capability) enables application of nanostructured garnet as a magnetic relief replicator/visualizer and as a material for low power consuming displays.

  12. Association to HeLa cells and surface behavior of exogenous gangliosides studied with a fluorescent derivative of GM1

    SciTech Connect

    Masserini, M.; Giuliani, A.; Palestini, P.; Acquotti, D.; Pitto, M.; Chigorno, V.; Tettamanti, G. )

    1990-01-23

    Cultured HeLa cells were incubated with pyrene-GM1/{sup 3}H-radiolabeled GM1 ganglioside (1:4 M/M) mixtures for various times. The process of association of pyrene-GM1 with cells was qualitatively and quantitatively the same as that of {sup 3}H-GM1. The pyrene-GM1 and {sup 3}H-GM1 proportions in the various forms of association with cells were similar to that of the starting ganglioside mixture. After 2-h incubation, the association of ganglioside with cells was well established whereas almost no metabolic processing had occurred. During a 24-h incubation, pyrene- and {sup 3}H-GM1 underwent similar metabolic processing and gave rise to catabolic (GM2 and GM3) and anabolic (GDla) derivatives. Fluorescence spectroscopy experiments carried out with the excimer formation technique on subcellular fractions containing plasma membranes showed that exogenous ganglioside was, in part, associated with the cells in a micellar form removable by trypsin treatment, and in part inserted in a seemingly molecular dispersion. Addition of Ca{sup 2+} salts caused aggregation of the ganglioside, as indicated by the increase of the excimer:monomer fluorescence ratio. The phenomenon was Ca{sup 2+} concentration dependent (maximum at 10 mM), and subsequent addition of EDTA has no effect. The saccharide portion of exogenously incorporated pyrene-GM1 was available to interact with external ligands, as shown by its ability to bind cholera toxin whose addition reduced the collision rate among the ganglioside lipid moieties.

  13. Fucosyl-GM1a, an endoglycoceramidase-resistant ganglioside of porcine brain.

    PubMed

    Xu, Xu; Monjusho, Hatsumi; Inagaki, Masanori; Hama, Yoichiro; Yamaguchi, Kuniko; Sakaguchi, Keishi; Iwamori, Masao; Okino, Nozomu; Ito, Makoto

    2007-01-01

    The use of bovine brain has been prohibited in many countries because of the world-wide prevalence of mad cow disease, and thus porcine brain is expected to be a new source for the preparation of gangliosides. Here, we report the presence of a ganglioside in porcine brain which is strongly resistant to hydrolysis by endoglycoceramidase, an enzyme capable of cleaving the glycosidic linkage between oligosaccharides and ceramides of various glycosphingolipids. Five major gangliosides (designated PBG-1, 2, 3, 4, 5) were extracted from porcine brain by Folch's partition, followed by mild alkaline hydrolysis and PBA column chromatography. We found that PBG-2, but not the others, was strongly resistant to hydrolysis by the enzyme. After the purification of PBG-2 with Q-Sepharose, Silica gel 60 and Prosep-PB chromatographies, the structure of PBG-2 was determined by GC, GC-MS, FAB-MS and NMR spectroscopy as Fucalpha1-2Galbeta1-3GalNAcbeta1-4(NeuAcalpha2-3)Galbeta1-4Glcbeta1-1'Cer (fucosyl-GM1a). The ceramide was mainly composed of C18:0 and C20:0 fatty acids and d18:1 and d20:1 sphingoid bases. The apparent kcat/Km for fucosyl-GM1a was found to be 30 times lower than that for GM1a, indicating that terminal fucosylation makes GM1a resistant to hydrolysis by the enzyme. This report indicates the usefulness of endoglycoceramidase to prepare fucosyl-GM1a from porcine brain. PMID:17167042

  14. Condensing and Fluidizing Effects of Ganglioside GM1 on Phospholipid Films

    PubMed Central

    Frey, Shelli L.; Chi, Eva Y.; Arratia, Cristóbal; Majewski, Jaroslaw; Kjaer, Kristian; Lee, Ka Yee C.

    2008-01-01

    Mixed monolayers of the ganglioside GM1 and the lipid dipalmitoylphosphatidlycholine (DPPC) at air-water and solid-air interfaces were investigated using various biophysical techniques to ascertain the location and phase behavior of the ganglioside molecules in a mixed membrane. The effects induced by GM1 on the mean molecular area of the binary mixtures and the phase behavior of DPPC were followed for GM1 concentrations ranging from 5 to 70 mol %. Surface pressure isotherms and fluorescence microscopy imaging of domain formation indicate that at low concentrations of GM1 (<25 mol %), the monolayer becomes continually more condensed than DPPC upon further addition of ganglioside. At higher GM1 concentrations (>25 mol %), the mixed monolayer becomes more expanded or fluid-like. After deposition onto a solid substrate, atomic force microscopy imaging of these lipid monolayers showed that GM1 and DPPC pack cooperatively in the condensed phase domain to form geometrically packed complexes that are more ordered than either individual component as evidenced by a more extended total height of the complex arising from a well-packed hydrocarbon tail region. Grazing incidence x-ray diffraction on the DPPC/GM1 binary mixture provides evidence that ordering can emerge when two otherwise fluid components are mixed together. The addition of GM1 to DPPC gives rise to a unit cell that differs from that of a pure DPPC monolayer. To determine the region of the GM1 molecule that interacts with the DPPC molecule and causes condensation and subsequent expansion of the monolayer, surface pressure isotherms were obtained with molecules modeling the backbone or headgroup portions of the GM1 molecule. The observed concentration-dependent condensing and fluidizing effects are specific to the rigid, sugar headgroup portion of the GM1 molecule. PMID:18192361

  15. Ganglioside GD1a promotes oocyte maturation, furthers preimplantation development, and increases blastocyst quality in pigs

    PubMed Central

    KIM, Jin-Woo; PARK, Hyo-Jin; CHAE, Sung-Kyu; AHN, Jae-Hyun; DO, Geon-Yeop; CHOO, Young-Kug; PARK, Joung Jun; JUNG, Bae Dong; KIM, Sun-Uk; CHANG, Kyu-Tae; KOO, Deog-Bon

    2016-01-01

    Gangliosides are key lipid molecules required for the regulation of cellular processes such as proliferation, differentiation, and cell signaling, including signaling of epidermal growth factor receptor (EGFR). Epidermal growth factor (EGF) has long been considered a potential regulator of meiotic and cytoplasmic maturation in mammalian oocytes. However, there is no report on the direct effect of ganglioside GD1a in porcine oocyte maturation. In this study, we first investigated a functional link between GD1a and meiotic maturation during in vitro maturation (IVM) of porcine embryos. Moreover, we confirmed the effect of exogenous GD1a treatment on blastocyst development, quality, and fertilization rate in early embryonic development. First, we observed that the protein level of ST3GAL2, a GD1a synthesizing enzyme, significantly increased (P < 0.01) in cumulus-oocyte-complexes (COCs) during IVM progress. The proportion of arrested germinal vesicles (GV) increased in oocytes treated with EGF+GD1a (41.6 ± 1.5%) at the IVM I stage. Upon completion of meiotic maturation, the proportion of metaphase II (M II) was significantly higher (P < 0.05) in the EGF+GD1a (89.9 ± 3.6%) treated group. After IVF, the percentage of penetrated oocytes was significantly higher (P < 0.05) in the EGF+GD1a (89.1 ± 2.3%) treated group than in the control group. Furthermore, exogenous GD1a treatment improved the developmental competence and quality of blastocysts during preimplantation embryo development stage. These results suggest that ganglioside GD1a may play an important role in IVM mechanisms of porcine maturation capacity. Furthermore, our findings will be helpful for better promoting the embryo development and blastocyst quality in pigs. PMID:26860251

  16. Development of an immunoassay for rapid detection of ganglioside GM(1) mimicry in Campylobacter jejuni strains.

    PubMed

    Prendergast, M M; Kosunen, T U; Moran, A P

    2001-04-01

    Mimicry of peripheral nerve gangliosides by Campylobacter jejuni lipopolysaccharides (LPSs) has been proposed to induce cross-reacting antiganglioside antibodies in Guillain-Barré syndrome (GBS). Because current methods for LPS characterization are labor-intensive and inhibit the screening of large numbers of strains, a rapid GM(1) epitope screening assay was developed. Biomass from two agar plates of confluent growth yielded sufficient LPS using a novel phenol-water and ether extraction procedure. Extracts of LPS were reacted with cholera toxin (GM(1) ligand), peanut agglutinin (Gal beta1-->3GalNAc ligand), and anti-GM(1) antibodies. After the assay was validated, 12 of 59 (20%) C. jejuni serostrains, including four serotypes that have not previously been associated with GBS, reacted with two or more anti-GM(1) ganglioside reagents. Subsequently, LPS extracts from 5 of 7 (71%) C. jejuni isolates and 2 of 3 (67%) C. jejuni culture collection strains bore GM(1) structures. Overall, the assay system was reliable, efficient, and reproducible and may be adapted for large-scale epidemiological studies.

  17. Packing of ganglioside-phospholipid monolayers: an x-ray diffraction and reflectivity study.

    PubMed

    Majewski, J; Kuhl, T L; Kjaer, K; Smith, G S

    2001-11-01

    Using synchrotron grazing-incidence x-ray diffraction (GIXD) and reflectivity, the in-plane and out-of-plane structure of mixed ganglioside-phospholipid monolayers was investigated at the air-water interface. Mixed monolayers of 0, 5, 10, 20, and 100 mol% ganglioside GM(1) and the phospholipid dipalmitoylphosphatidylethanolamine (DPPE) were studied in the solid phase at 23 degrees C and a surface pressure of 45 mN/m. At these concentrations and conditions the two components do not phase-separate and no evidence for domain formation was observed. X-ray scattering measurements reveal that GM(1) is accommodated within the host DPPE monolayer and does not distort the hexagonal in-plane unit cell or out-of-plane two-dimensional (2-D) packing compared with a pure DPPE monolayer. The oligosaccharide headgroups were found to extend normally from the monolayer surface, and the incorporation of these glycolipids into DPPE monolayers did not affect hydrocarbon tail packing (fluidization or condensation of the hydrocarbon region). This is in contrast to previous investigations of lipopolymer-lipid mixtures, where the packing structure of phospholipid monolayers was greatly altered by the inclusion of lipids bearing hydrophilic polymer groups. Indeed, the lack of packing disruptions by the oligosaccharide groups indicates that protein-GM(1) interactions, including binding, insertion, chain fluidization, and domain formation (lipid rafts), can be studied in 2-D monolayers using scattering techniques.

  18. Plasma membrane ganglioside sialidase regulates axonal growth and regeneration in hippocampal neurons in culture.

    PubMed

    Rodriguez, J A; Piddini, E; Hasegawa, T; Miyagi, T; Dotti, C G

    2001-11-01

    It has been long recognized that the ganglioside GM1 plays a role in axonal growth and neuronal differentiation. However, the involvement of plasma membrane GM1 has been difficult to elucidate. This is possible now thanks to the recent cloning of plasma membrane ganglioside sialidase (PMGS), the enzyme responsible for the localized hydrolysis of oligosialogangliosides into GM1. In this work we show that PMGS mRNA and protein levels are high at early developmental stages of the hippocampus and low in adulthood both in vivo and in vitro. We also demonstrate that inhibition of PMGS activity blocks axonal elongation, whereas the increase in PMGS activity dramatically enhances axon growth and accelerates the polarization of cytoskeletal proteins. Finally, we show that axotomy close to the cell body in PMGS overexpressing neurons results in the regrowth of the original axon instead of randomly, as is the case in control neurons. In all, these results imply that PMGS activity through the modulation of GM1 surface levels is an important component of the machinery controlling axonal growth. We hypothesize that increasing PMGS activity in the adult nervous system may be useful to improve regeneration after nerve damage. PMID:11606627

  19. Ganglioside GD2 as a Therapeutic Target for Antibody-Mediated Therapy in Osteosarcoma

    PubMed Central

    Roth, Michael; Linkowski, Marissa; Tarim, John; Piperdi, Sajida; Sowers, Rebecca; Geller, David; Gill, Jonathan; Gorlick, Richard

    2013-01-01

    BACKGROUND Survival outcomes for patients with osteosarcoma have remained stagnant over the past three decades. Targeting of ganglioside GD2, a glycosphingolipid on the cell surface of some tumors, with immunotherapy has resulted in improved outcomes for patients with neuroblastoma. The expression pattern of GD2 was examined in osteosarcoma. METHODS Immunohistochemistry was performed on osteosarcoma samples from patients at the time of initial biopsy, definitive surgery, and recurrence. The intensity and location of staining were scored. Cell-based ELISA was performed on osteosarcoma cell lines to quantitate the level of GD2 expression. RESULTS Forty-four osteosarcoma samples were evaluated by immunohistochemistry, including 8 samples from the initial biopsy, 28 samples from the definitive surgery, and 8 samples from the time of recurrence. GD2 was expressed on all 44 osteosarcoma samples. Osteosarcoma tissue obtained at the time of recurrence showed higher intensity of staining compared to samples obtained at initial biopsy and definitive surgery (p=0.016). The majority of osteosarcoma cell lines expressed GD2 at higher levels than the neuroblastoma cell line BE(2)-C. CONCLUSIONS Ganglioside GD2 is highly expressed on osteosarcomas. Clinical trials are needed to assess the efficacy of targeting GD2 in patients with osteosarcoma. PMID:24166473

  20. Detection of cholera toxin in seafood using a ganglioside-liposome immunoassay.

    PubMed

    Ahn, Soohyoun; Durst, Richard A

    2008-05-01

    Microbiological contamination of foods continues to be a major concern in public health. Biological toxins are one class of important contaminants that can cause various human diseases. Outbreaks related to contamination by biological toxins or toxin-producing microorganisms have made it extremely important to develop rapid (approximately 20 min), sensitive and cost-effective analytical methods. This paper describes the development of a sensitive bioassay for the detection of cholera toxin (CT) in selected seafood samples, using ganglioside-incorporated liposomes. In this study, the assays were run with food samples spiked with various concentrations of CT. The limit of detection (LOD) increased by a factor of about 10-20 in most food samples, compared with the LOD in the buffer system previously reported. However, the LOD of toxins in food samples (8 × 10-3 × 10(3) fg/mL for CT) was still comparable to, or lower than, that previously reported for other assays. The results from this study demonstrate that the bioassays using ganglioside-liposomes can detect the toxin directly in the field screening of food samples rapidly, simply and reliably, without the need for complex instrumentation. PMID:17899040

  1. Identification of a Unique Ganglioside Binding Loop within Botulinum Neurotoxins C and D-SA

    SciTech Connect

    Karalewitz, Andrew P.-A.; Kroken, Abby R.; Fu, Zhuji; Baldwin, Michael R.; Kim, Jung-Ja P.; Barbieri, Joseph T.

    2010-09-22

    The botulinum neurotoxins (BoNTs) are the most potent protein toxins for humans. There are seven serotypes of BoNTs (A-G) based on a lack of cross antiserum neutralization. BoNTs utilize gangliosides as components of the host receptors for binding and entry into neurons. Members of BoNT/C and BoNT/D serotypes include mosaic toxins that are organized in D/C and C/D toxins. One D/C mosaic toxin, BoNT/D-South Africa (BoNT/D-SA), was not fully neutralized by immunization with BoNT serotype C or D, which stimulated this study. Here the crystal structures of the receptor binding domains of BoNT/C, BoNT/D, and BoNT/D-SA are presented. Biochemical and cell binding studies show that BoNT/C and BoNT/D-SA possess unique mechanisms for ganglioside binding. These studies provide new information about how the BoNTs can enter host cells as well as a basis for understanding the immunological diversity of these neurotoxins.

  2. Efficacy of Ganglioside GM1 in the Treatment of Postherpetic Neuralgia.

    PubMed

    Koju, Ram Prasad; Lei, Tie-Chi

    2016-07-01

    Postherpetic neuralgia (PHN) is a commonest and difficult-to-manage complication of Herpes zoster. This comparative study included 140 cases of PHN admitted in the department of dermatology in Renmin Hospital of Wuhan University, Wuhan, China, from March 2014 to February 2015, divided into a control and a study group. In addition to the combination of antiviral, analgesic, and neurotrophic agents given to the control group, additional ganglioside GM1 was given to patients in the study group. Pain assessment was performed at the time of admission, and then on the third, seventh and tenth day of treatment, on both groups, using a 10 cm visual analogue scale (VAS). There was a significant statistical difference between the pain VAS score of the two groups, on the seventh day (3.73 ±1.66 vs. 3.03 ±1.86, p=0.024) and on the tenth day (3.25 ±1.78 vs. 2.20 ±1.59, p=0.006) of treatment. The number of patients who have good /and complete response (37.5%) were largely higher in the study group than those in the control group (15%, p < 0.05). This finding demonstrates that the administration of ganglioside GM1 may potentially serve as a neoadjuvant therapy to reduce the severity and duration of pain in PHN patients. PMID:27504562

  3. Evidence for the existence of ganglioside molecules in the antigen of Entamoeba histolytica.

    PubMed

    Sorice, M; Griggi, T; Nicodemo, G; Garofalo, T; Marangi, M; Sanguigni, S; Becker, S I; Mirelman, D

    1996-03-01

    Gangliosides were found to be present in Entamoeba histolytica. They were extracted from lyophilized trophozoites of the pathogenic strain HM-1:IMSS and purified by high performance thin-layer chromatography. Two resorcinol-positive bands, comigrating with GM2 and GD1a were demonstrated, revealing the existence of ganglioside molecules in Entamoeba histolytica. The GM2 content, determined as lipid-bound sialic acid, was 1.5 micrograms/10(8) amoebae, the content of the GD1a comigrating band was 0.32 microgram/10(8) amoebae. The identity of the GM2 comigrating band was confirmed by TLC immunostaining, using the monoclonal anti-GM2 antibody GMB28. Furthermore, six out of ten anti-amoeba positive sera selectively reacted with the GM2 comigrating band, as revealed by immunostaining on TLC plates. Absorption tests revealed that preincubation of anti-amoeba positive sera with standard GM2 was followed by a significant decrease in the reaction with amoeba trophozoites by indirect immunofluorescence. These results demonstrate that a GM2 comigrating component of Entamoeba histolytica may be one of the antigens responsible for the appearance of circulating antibodies in patients with amoebiasis. PMID:9223167

  4. Identification of a unique ganglioside binding loop within botulinum neurotoxins C and D-SA .

    PubMed

    Karalewitz, Andrew P-A; Kroken, Abby R; Fu, Zhuji; Baldwin, Michael R; Kim, Jung-Ja P; Barbieri, Joseph T

    2010-09-21

    The botulinum neurotoxins (BoNTs) are the most potent protein toxins for humans. There are seven serotypes of BoNTs (A-G) based on a lack of cross antiserum neutralization. BoNTs utilize gangliosides as components of the host receptors for binding and entry into neurons. Members of BoNT/C and BoNT/D serotypes include mosaic toxins that are organized in D/C and C/D toxins. One D/C mosaic toxin, BoNT/D-South Africa (BoNT/D-SA), was not fully neutralized by immunization with BoNT serotype C or D, which stimulated this study. Here the crystal structures of the receptor binding domains of BoNT/C, BoNT/D, and BoNT/D-SA are presented. Biochemical and cell binding studies show that BoNT/C and BoNT/D-SA possess unique mechanisms for ganglioside binding. These studies provide new information about how the BoNTs can enter host cells as well as a basis for understanding the immunological diversity of these neurotoxins.

  5. GM1 and GD1a gangliosides modulate toxic and inflammatory effects of E. coli lipopolysaccharide by preventing TLR4 translocation into lipid rafts.

    PubMed

    Nikolaeva, Svetlana; Bayunova, Lubov; Sokolova, Tatyana; Vlasova, Yulia; Bachteeva, Vera; Avrova, Natalia; Parnova, Rimma

    2015-03-01

    Exogenous gangliosides are known to inhibit the effects of Escherichia coli lipopolysaccharide (LPS) in different cells exhibiting anti-inflammatory and immunosuppressive activities. The mechanisms underlying ganglioside action are not fully understood. Because LPS recognition and receptor complex formation occur in lipid rafts, and gangliosides play a key role in their maintenance, we hypothesize that protective effects of exogenous gangliosides would depend on inhibition of LPS signaling via prevention of TLR4 translocation into lipid rafts. The effect of GM1 and GD1a gangliosides on LPS-induced toxic and inflammatory reactions in PC12 cells, and in epithelial cells isolated from the frog urinary bladder, was studied. In PC12 cells, GD1a and GM1 significantly reduced the effect of LPS on the decrease of cell survival and on stimulation of reactive oxygen species production. In epithelial cells, gangliosides decreased LPS-stimulated iNOS expression, NO, and PGE2 production. Subcellular fractionation, in combination with immunoblotting, showed that pretreatment of cells with GM1, GD1a, or methyl-β-cyclodextrin, completely eliminated the effect of LPS on translocation of TLR4 into lipid rafts. The results are consistent with the hypothesis that ganglioside-induced prevention of TLR4 translocation into lipid rafts could be a mechanism of protection against LPS in various cells.

  6. Gd3+-1,4,7,10-Tetraazacyclododecane-1,4,7-triacetic-2-hydroxypropyl-β-cyclodextrin/Pluronic Polyrotaxane as a Long Circulating High Relaxivity MRI Contrast Agent.

    PubMed

    Zhou, Zhuxian; Mondjinou, Yawo; Hyun, Seok-Hee; Kulkarni, Aditya; Lu, Zheng-Rong; Thompson, David H

    2015-10-14

    A multivalent magnetic resonance imaging agent based on a 2-hydroxypropyl-β-cyclodextrin (HPCD):Pluronic F127 polyrotaxane carrier has been synthesized, and its blood pool contrast properties have been characterized. This Gd3+-DO3A-HPCD/Pluronic polyrotaxane construct is shown to circulate for more than 30 min and provide >100-fold vascular enhancement relative to the monomeric Gd3+-DO3A-HPCD control that is rapidly cleared via the kidney. The high r1 relaxivity at 37 °C (23.83 mM(-1) s(-1) at 1.5 T; 34.08 mM(-1) s(-1) at 0.5 T), extended blood circulation, well-known pharmacology of the polyrotaxane precursors, and absence of acute toxicity make it a highly attractive blood pool contrast agent candidate.

  7. Alterations in cholesterol and ganglioside GM1 content of lipid rafts in platelets from patients with Alzheimer disease.

    PubMed

    Liu, Li; Zhang, Ke; Tan, Liang; Chen, Yu-Hua; Cao, Yun-Peng

    2015-01-01

    The aim of this study was to investigate the changes in the protein, cholesterol, and ganglioside GM1 content of lipid rafts in platelets from patients with Alzheimer disease (AD), and identify potential blood biomarkers of the disease. A total of 31 Chinese patients with AD and 31 aged-matched control subjects were selected. Lipid rafts were isolated from platelets using Optiprep gradient centrifugation. The protein content of lipid rafts was evaluated using Micro BCA assay, the cholesterol content using molecular probes, ganglioside GM1 content using colorimetry and dot-blotting analysis. The results showed that the cholesterol and ganglioside GM1 content of lipid rafts from platelets was significantly higher in patients with AD than aged-matched control subjects, whereas the protein content of lipid rafts did not show any differences between the 2 groups. These results indicate that the increases in the cholesterol and ganglioside GM1 content of lipid rafts from the platelets of patients with AD might serve as a biochemical adjunct to the clinical diagnosis of AD.

  8. The metabolism of Tay-Sachs ganglioside: catabolic studies with lysosomal enzymes from normal and Tay-Sachs brain tissue.

    PubMed

    Tallman, J F; Johnson, W G; Brady, R O

    1972-09-01

    The catabolism of Tay-Sachs ganglioside, N-acetylgalactosaminyl- (N-acetylneuraminosyl) -galactosylglucosylceramide, has been studied in lysosomal preparations from normal human brain and brain obtained at biopsy from Tay-Sachs patients. Utilizing Tay-Sachs ganglioside labeled with (14)C in the N-acetylgalactosaminyl portion or (3)H in the N-acetylneuraminosyl portion, the catabolism of Tay-Sachs ganglioside may be initiated by either the removal of the molecule of N-acetylgalactosamine or N-acetylneuraminic acid. The activity of the N-acetylgalactosamine-cleaving enzyme (hexosaminidase) is drastically diminished in such preparations from Tay-Sachs brain whereas the activity of the N-acetylneuraminic acid-cleaving enzyme (neuraminidase) is at a normal level. Total hexosaminidase activity as measured with an artificial fluorogenic substrate is increased in tissues obtained from patients with the B variant form of Tay-Sachs disease and it is virtually absent in the O-variant patients. The addition of purified neuraminidase and various purified hexosaminidases exerted only a minimal synergistic effect on the hydrolysis of Tay-Sachs ganglioside in the lysosomal preparations from the control or patient with the O variant of Tay-Sachs disease.

  9. Deciphering the Glycolipid Code of Alzheimer's and Parkinson's Amyloid Proteins Allowed the Creation of a Universal Ganglioside-Binding Peptide

    PubMed Central

    Yahi, Nouara; Fantini, Jacques

    2014-01-01

    A broad range of microbial and amyloid proteins interact with cell surface glycolipids which behave as infectivity and/or toxicity cofactors in human pathologies. Here we have deciphered the biochemical code that determines the glycolipid-binding specificity of two major amyloid proteins, Alzheimer's β-amyloid peptide (Aβ) and Parkinson's disease associated protein α-synuclein. We showed that both proteins interact with selected glycolipids through a common loop-shaped motif exhibiting little sequence homology. This 12-residue domain corresponded to fragments 34-45 of α-synuclein and 5-16 of Aβ. By modulating the amino acid sequence of α-synuclein at only two positions in which we introduced a pair of histidine residues found in Aβ, we created a chimeric α-synuclein/Aβ peptide with extended ganglioside-binding properties. This chimeric peptide retained the property of α-synuclein to recognize GM3, and acquired the capacity to recognize GM1 (an Aβ-inherited characteristic). Free histidine (but not tryptophan or asparagine) and Zn2+ (but not Na+) prevented this interaction, confirming the key role of His-13 and His-14 in ganglioside binding. Molecular dynamics studies suggested that the chimeric peptide recognized cholesterol-constrained conformers of GM1, including typical chalice-shaped dimers, that are representative of the condensed cholesterol-ganglioside complexes found in lipid raft domains of the plasma membrane of neural cells. Correspondingly, the peptide had a particular affinity for raft-like membranes containing both GM1 and cholesterol. The chimeric peptide also interacted with several other gangliosides, including major brain gangliosides (GM4, GD1a, GD1b, and GT1b) but not with neutral glycolipids such as GlcCer, LacCer or asialo-GM1. It could inhibit the binding of Aβ1-42 onto neural SH-SY5Y cells and did not induce toxicity in these cells. In conclusion, deciphering the glycolipid code of amyloid proteins allowed us to create a universal

  10. Suitability of the rare-earth compounds Dy2Ti2O7 and Gd3Al5O12 for low temperature (4K-20K) magnetic refrigeration cycle

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1973-01-01

    Measurements were made of the magnetic entropy and magnetization of powered samples of the compounds Dy2Ti2O7 and Gd3Al5O12. The magnetization was measured for temperatures at and below 4.2 K, in applied fields ranging to 7.0 tesla. Isothermal changes in magnetic entropy were measured for temperatures from 1.2 to 20 K, in applied fields up to 10 tesla. The results of the measurements are consistent with a doublet ground state for Dy2Ti2O7, and an eight-fold degenerate ground state for Gd3Al5O12. Absolute values of magnetic entropy have been obtained at the lower temperatures, permitting the isotherms to be properly located in the S-H plane with the use of adiabatic magnetization data. The iso-field lines in the S-T plane were determined. The results indicate that Dy2Ti2O7 can absorb a maximum of 71 + or - 4 joules/kg of heat at 4.2 K, while Gd3Al5O12 can absorb 233 + or - joules/kg at the same temperature. The large difference between the two is most likely a result of crystal field interactions in the dysoprosium compound. Both materials can be cycled adiabatically between 4.2 and 20 K.

  11. Luminescence properties of an orange-red phosphor GdAl3(BO3)4:Sm3+ under VUV excitation and energy transfer from Gd3+ to Sm3+

    NASA Astrophysics Data System (ADS)

    He, Jin; Zhang, Su; Zhou, Jianbang; Zhong, Jiuping; Liang, Hongbin; Sun, Shuaishuai; Huang, Yan; Tao, Ye

    2015-01-01

    In order to develop a new warm-color emission phosphor under vacuum ultraviolet (VUV) excitation, trivalent samarium ion (Sm3+) doped GdAl3(BO3)4 was prepared by a solid state reaction technique at high temperature. The VUV excitation and emission spectra of as-synthesized sample GdAl3(BO3)4:Sm3+ were determined in the Beijing Synchrotron Radiation Facilities (BSRF). Compared with the emission of GdAl3(BO3)4:Eu3+, GdAl3(BO3)4:Sm3+ shows an orange-red emission under Xe 172 nm VUV excitation, which indicates that Sm3+ ion can be a possible activator to obtain warm color emission in the field of lighting. Furthermore, for improving the emission of Sm3+ doped in GdAl3(BO3)4, the energy transfer process from Gd3+ in the host to the activator Sm3+ was investigated through the analysis of spectroscopic characteristics and luminescence decay curves of GdAl3(BO3)4:Sm3+. The results reveal that there exists energy transfer from Gd3+ to Sm3+, but the energy transfer from Sm3+ to Gd3+ is inefficient.

  12. Sialidase NEU3 Dynamically Associates to Different Membrane Domains Specifically Modifying Their Ganglioside Pattern and Triggering Akt Phosphorylation

    PubMed Central

    Pasini, Mario; Dileo, Loredana; Orizio, Flavia; Monti, Eugenio; Caimi, Luigi; Venerando, Bruno; Bresciani, Roberto

    2014-01-01

    Lipid rafts are known to regulate several membrane functions such as signaling, trafficking and cellular adhesion. The local enrichment in sphingolipids and cholesterol together with the low protein content allows their separation by density gradient flotation after extraction with non-ionic detergent at low temperature. These structures are also referred to as detergent resistant membranes (DRM). Among sphingolipids, gangliosides play important roles in different biological events, including signal transduction and tumorigenesis. Sialidase NEU3 shows high enzymatic specificity toward gangliosides. Moreover, the enzyme is present both at the cell surface and in endosomal structures and cofractionates with caveolin. Although changes in the expression level of NEU3 have been correlated to different tumors, little is known about the precise distribution of the protein and its ability in modifying the ganglioside composition of DRM and non-DRM, thus regulating intracellular events. By means of inducible expression cell system we found that i) newly synthesized NEU3 is initially associated to non-DRM; ii) at steady state the protein is equally distributed between the two membrane subcompartments, i.e., DRM and non-DRM; iii) NEU3 is degraded via the proteasomal pathway; iv) the enzyme specifically modifies the ganglioside composition of the membrane areas where it resides; and v) NEU3 triggers phosphorylation of Akt, even in absence of exogenously administered EGF. Taken together our data demonstrate that NEU3 regulates the DRM ganglioside content and it can be considered as a modulator of Akt phosphorylation, further supporting the role of this enzyme in cancer and tumorigenesis. PMID:24925219

  13. Ganglioside Structure Dictates Signal Transduction by Cholera Toxin and Association with Caveolae-like Membrane Domains in Polarized Epithelia

    PubMed Central

    Wolf, Anne A.; Jobling, Michael G.; Wimer-Mackin, Susan; Ferguson-Maltzman, Margaret; Madara, James L.; Holmes, Randall K.; Lencer, Wayne I.

    1998-01-01

    In polarized cells, signal transduction by cholera toxin (CT) requires apical endocytosis and retrograde transport into Golgi cisternae and perhaps ER (Lencer, W.I., C. Constable, S. Moe, M. Jobling, H.M. Webb, S. Ruston, J.L. Madara, T. Hirst, and R. Holmes. 1995. J. Cell Biol. 131:951–962). In this study, we tested whether CT's apical membrane receptor ganglioside GM1 acts specifically in toxin action. To do so, we used CT and the related Escherichia coli heat-labile type II enterotoxin LTIIb. CT and LTIIb distinguish between gangliosides GM1 and GD1a at the cell surface by virtue of their dissimilar receptor-binding B subunits. The enzymatically active A subunits, however, are homologous. While both toxins bound specifically to human intestinal T84 cells (Kd ≈ 5 nM), only CT elicited a cAMP-dependent Cl− secretory response. LTIIb, however, was more potent than CT in eliciting a cAMP-dependent response from mouse Y1 adrenal cells (toxic dose 10 vs. 300 pg/well). In T84 cells, CT fractionated with caveolae-like detergent-insoluble membranes, but LTIIb did not. To investigate further the relationship between the specificity of ganglioside binding and partitioning into detergent-insoluble membranes and signal transduction, CT and LTIIb chimeric toxins were prepared. Analysis of these chimeric toxins confirmed that toxin-induced signal transduction depended critically on the specificity of ganglioside structure. The mechanism(s) by which ganglioside GM1 functions in signal transduction likely depends on coupling CT with caveolae or caveolae-related membrane domains. PMID:9585411

  14. A novel one-step synthesis of Gd3+-incorporated mesoporous SiO2 nanoparticles for use as an efficient MRI contrast agent.

    PubMed

    Shao, Yuan-Zhi; Liu, Li-Zhi; Song, Shu-qin; Cao, Ri-hui; Liu, Huan; Cui, Chun-yan; Li, Xing; Bie, Meng-Jie; Li, Li

    2011-01-01

    Molecular imaging has generated a demand for more sensitive contrast agents for magnetic resonance (MR) imaging. We synthesized, by a novel one-step method, Gd(3+) incorporated mesoporous SiO(2) nanoparticles, Gd(2)O(3)@SiO(2), for use as an efficient contrast agent. The prepared nanoparticles were also coated with poly(lactic-co-glycolic acid) (PLGA). The size, morphology, composition and Brunauer-Emmett-Teller specific surface area of the nanoparticles were evaluated. The Gd(2)O(3)@SiO(2) nanoparticles possess intragranular network morphology with a uniform size distribution and an average size of approximately 20-40 nm. The PLGA-coated nanoparticles were spherical or near-spherical in shape with a diameter of approximately 120 nm, a smooth surface, and neither aggregation nor adhesion tendencies. No free Gd ions were detected to dissociate from Gd(2)O(3)@SiO(2) even up to the limit (<0.03 mg/l) of the ICP equipment (IRIS Advantage). Our theoretical computation based on density functional theory (using DMol3, Materials Studio) revealed that the Gd(2)O(3) molecules are fully absorbed on the interface of mesoporous SiO(2) with a stable state of lower energy. Both Gd(2)O(3)@SiO(2) and PLGA-coated Gd(2)O(3)@SiO(2) samples have a larger T(1) relaxivitiy than commercial gadolinium diethylene triaminepentaacetate (Gd-DTPA). In vitro and in vivo MR images using the Gd(2)O(3)@SiO(2) nanoparticles were observed with a 1.5 T clinical MR scanner and compared with the images using Gd-DTPA. The Gd(2)O(3)@SiO(2) nanoparticles display a better magnetic property than commercial Gd-DTPA. In vivo MR imaging demonstrated that the nanoparticles were mainly distributed in the liver. Strong enhancement was also detected in nasopharyngeal carcinoma CNE-2 xenografted tumors. The Gd(2)O(3)@SiO(2) nanoparticles are not only potential candidates for highly efficient contrast agents for MR imaging, but also might be developed into potent targeted probes for in vivo molecular imaging of

  15. Optical emission, shock-induced opacity, temperatures, and melting of Gd3Ga5O12 single crystals shock-compressed from 41 to 290 GPa

    NASA Astrophysics Data System (ADS)

    Zhou, Xianming; Nellis, William J.; Li, Jiabo; Li, Jun; Zhao, Wanguang; Liu, Xun; Cao, Xiuxia; Liu, Qiancheng; Xue, Tao; Wu, Qiang; Mashimo, T.

    2015-08-01

    Strong oxides at high shock pressures have broad crossovers from elastic solids at ambient to failure by plastic deformation, to heterogeneous deformation to weak solids, to fluid-like solids that equilibrate thermally in a few ns, to melting and, at sufficiently high shock pressures and temperatures, to metallic fluid oxides. This sequence of crossovers in single-crystal cubic Gd3Ga5O12 (Gd-Ga Garnet-GGG) has been diagnosed by fast emission spectroscopy using a 16-channel optical pyrometer in the spectral range 400-800 nm with bandwidths per channel of 10 nm, a writing time of ˜1000 ns and time resolution of 3 ns. Spectra were measured at shock pressures from 40 to 290 GPa (100 GPa = 1 Mbar) with corresponding gray-body temperatures from 3000 to 8000 K. Experimental lifetimes were a few 100 ns. Below 130 GPa, emission is heterogeneous and measured temperatures are indicative of melting temperatures in grain boundary regions rather than bulk temperatures. At 130 GPa and 2200 K, GGG equilibrates thermally and homogeneously in a thin opaque shock front. This crossover has a characteristic spectral signature in going from partially transmitting shock-heated material behind the shock front to an opaque shock front. Opacity is caused by optical scattering and absorption of light generated by fast compression. GGG melts at ˜5000 K in a two-phase region at shock pressures in the range 200 GPa to 217 GPa. Hugoniot equation-of-state data were measured by a Doppler Pin SystemDPS with ps time resolution and are generally consistent with previous data. Extrapolation of previous electrical conductivity measurements indicates that GGG becomes a poor metal at a shock pressure above ˜400 GPa. Because the shock impedance of GGG is higher than that of Al2O3 used previously to make metallic fluid H (MFH), the use of GGG to make MFH will achieve higher pressures and lower temperatures than use of Al2O3. However, maximum dynamic pressures at which emission temperatures of fluid

  16. Structural and Enzymatic Characterization of NanS (YjhS) a 9-O-Acetyl N-acetylneuraminic Acid Esterase from Escherichia coli O157:H7

    SciTech Connect

    E Rangarajan; K Ruane; A Proteau; J Schrag; R Valladares; C Gonzalez; M Gilbert; A Yakunin; M Cygler

    2011-12-31

    There is a high prevalence of sialic acid in a number of different organisms, resulting in there being a myriad of different enzymes that can exploit it as a fermentable carbon source. One such enzyme is NanS, a carbohydrate esterase that we show here deacetylates the 9 position of 9-O-sialic acid so that it can be readily transported into the cell for catabolism. Through structural studies, we show that NanS adopts a SGNH hydrolase fold. Although the backbone of the structure is similar to previously characterized family members, sequence comparisons indicate that this family can be further subdivided into two subfamilies with somewhat different fingerprints. NanS is the founding member of group II. Its catalytic center contains Ser19 and His301 but no Asp/Glu is present to form the classical catalytic triad. The contribution of Ser19 and His301 to catalysis was confirmed by mutagenesis. In addition to structural characterization, we have mapped the specificity of NanS using a battery of substrates.

  17. Anti-ganglioside antibodies were not detected in human subjects infected with or vaccinated against 2009 pandemic influenza A (H1N1) virus.

    PubMed

    Lei, Ting; Siu, Kam-Leung; Kok, Kin-Hang; Chan, Kwok-Hung; Chan, Eric Y T; Hung, Ivan F N; To, Kelvin K W; Li, Patrick C K; Zhou, Jie; Zheng, Bo-Jian; Yuen, Kwok-Yung; Wang, Ming; Jin, Dong-Yan

    2012-03-30

    Recipients of influenza A (H1N1) vaccine in 1976 had an increased risk for the neurologic disorder Guillain-Barré syndrome (GBS). Anti-ganglioside antibodies, which might be associated with the development of GBS, were previously reported to be induced in mice immunized with an H1N1 vaccine of 1976 or another influenza vaccine. In this study we analyzed anti-ganglioside antibodies in human subjects infected with or vaccinated against 2009 pandemic H1N1, including eight patients diagnosed to have post-vaccination GBS. Antibodies against GM1 or another ganglioside were not detected in any subject or in vaccinated mice. Our results did not support the induction of anti-ganglioside antibodies by influenza viruses or vaccines.

  18. Lyso-GM2 ganglioside: a possible biomarker of Tay-Sachs disease and Sandhoff disease.

    PubMed

    Kodama, Takashi; Togawa, Tadayasu; Tsukimura, Takahiro; Kawashima, Ikuo; Matsuoka, Kazuhiko; Kitakaze, Keisuke; Tsuji, Daisuke; Itoh, Kohji; Ishida, Yo-Ichi; Suzuki, Minoru; Suzuki, Toshihiro; Sakuraba, Hitoshi

    2011-01-01

    To find a new biomarker of Tay-Sachs disease and Sandhoff disease. The lyso-GM2 ganglioside (lyso-GM2) levels in the brain and plasma in Sandhoff mice were measured by means of high performance liquid chromatography and the effect of a modified hexosaminidase (Hex) B exhibiting Hex A-like activity was examined. Then, the lyso-GM2 concentrations in human plasma samples were determined. The lyso-GM2 levels in the brain and plasma in Sandhoff mice were apparently increased compared with those in wild-type mice, and they decreased on intracerebroventricular administration of the modified Hex B. The lyso-GM2 levels in plasma of patients with Tay-Sachs disease and Sandhoff disease were increased, and the increase in lyso-GM2 was associated with a decrease in Hex A activity. Lyso-GM2 is expected to be a potential biomarker of Tay-Sachs disease and Sandhoff disease.

  19. Sialidase-mediated depletion of GM2 ganglioside in Tay-Sachs neuroglia cells.

    PubMed

    Igdoura, S A; Mertineit, C; Trasler, J M; Gravel, R A

    1999-06-01

    Tay-Sachs disease is a severe, inherited disease of the nervous system caused by accumulation of the brain lipid GM2 ganglioside. Mouse models of Tay-Sachs disease have revealed a metabolic bypass of the genetic defect based on the more potent activity of the enzyme sialidase towards GM2. To determine whether increasing the level of sialidase would produce a similar effect in human Tay-Sachs cells, we introduced a human sialidase cDNA into neuroglia cells derived from a Tay-Sachs fetus and demonstrated a dramatic reduction in the accumulated GM2. This outcome confirmed the reversibility of GM2 accumulation and opens the way to pharmacological induction or activation of sialidase for the treatment of human Tay-Sachs disease.

  20. Isolation and Structure Elucidation of GM4-Type Gangliosides from the Okinawan Starfish Protoreaster nodosus

    PubMed Central

    Pan, Ke; Tanaka, Chiaki; Inagaki, Masanori; Higuchi, Ryuichi; Miyamoto, Tomofumi

    2012-01-01

    Three new ganglioside molecular species, termed PNG-1, PNG-2A, and PNG-2B were isolated from pyloric caeca of the starfish Protoreaster nodosus. Their structures were elucidated using a combination of spectroscopic and chemical methods, and characterized as 1-O-[8-O-methyl-N-acetyl-α-neuraminosyl-(2→3)-β-galactopyranosyl]-ceramide for PNG-1, 1-O-[β-galactofuranosyl-(1→3)-α-galactopyranosyl-(1→4)-8-O-methyl-N-acetyl-α-neuraminosyl-(2→3)-β-galactopyranosyl]-ceramide for PNG-2A, and 1-O-[β-galactofuranosyl-(1→3)-α-galactopyranosyl-(1→9)-N-acetyl-α-neuraminosyl-(2→3)-β-galactopyranosyl]-ceramide for PNG-2B. PNG-2A and PNG-2B represent the first GM4 elongation products in nature. PMID:23203271

  1. Detergent extraction of cholera toxin and gangliosides from cultured cells and isolated membranes.

    PubMed

    Hagmann, J; Fishman, P H

    1982-04-29

    Choleragen, when bound to various cultured cells, resisted extraction by Triton X-100 under conditions which retained the cytoskeletal framework of the cells. The resistance (greater than 75% of the bound toxin) was observed in Friend erythroleukemic, mouse neuroblastoma N18 and NB41A and rat glioma C6 cells even though the different cells varied over 1000-fold in the number of toxin receptors. The extent of extraction did not depend on whether the cells were in monolayer culture of in suspension or whether choleragen was found at 0 or 37 degrees C. A similar resistance to extraction was also observed in membranes isolated from toxin-treated cells. Using more drastic conditions and other non-ionic detergents, 90% of the bound choleragen was solubilized from cells and membranes. When rat glioma C6 cells, which bind only small amounts of choleragen, were incubated with the ganglioside GM1, toxin binding was increased and the bound toxin was also resistant to extraction. When these cells were incubated with [3H]GM1, up to 70% of the cell-associated GM1 was extracted under the mild conditions. When the Gm1-labeled cells were incubated with choleragen or its B (binding) component, there was a significant reduction in the solubilization of GM1. Similar results were obtained with isolated membranes. When choleragen-receptor complexes were isolated from N18 cells labeled with [3H] galactose by immunoadsorption, only labeled GM1 was specifically recovered. These results suggest that it is the choleragen-ganglioside complex that is resistant to detergent extraction.

  2. Sialylated intravenous immunoglobulin suppress anti-ganglioside antibody mediated nerve injury.

    PubMed

    Zhang, Gang; Massaad, Cynthia A; Gao, Tong; Pillai, Laila; Bogdanova, Nataliia; Ghauri, Sameera; Sheikh, Kazim A

    2016-08-01

    The precise mechanisms underlying the efficacy of intravenous immunoglobulin (IVIg) in autoimmune neurological disorders including Guillain-Barré syndrome (GBS) are not known. Anti-ganglioside antibodies have been reported to be pathogenic in some variants of GBS, and we have developed passive transfer animal models to study anti-ganglioside antibody mediated-endoneurial inflammation and associated neuropathological effects and to evaluate the efficacy of new therapeutic approaches. Some studies indicate that IVIg's anti-inflammatory activity resides in a minor sialylated IVIg (sIVIg) fractions and is dependent on an innate Th2 response via binding to a specific ICAM3-grabbing nonintegrin related 1 receptor (SIGN-R1). Therefore the efficacy of IVIg, IVIg fractions with various IgG Fc sialylation status, and the involvement of Th2 pathway were examined in one of our animal model of antibody-mediated inhibition of axonal regeneration. We demonstrate that both IVIg and sIVIg ameliorated anti-glycan antibody mediated-pathological effect, whereas, the unsialylated fractions of IVIg were not beneficial in our model. Tenfold lower doses of sIVIg compared to whole IVIg provided equivalent efficacy in our studies. Moreover, we found that whole IVIg and sIVIg significantly upregulates the gene expression of IL-33, which itself can provide protection from antibody-mediated nerve injury in our model. Our results support that the SIGN-R1-Th2 pathway is involved in the anti-inflammatory effects of IVIg on endoneurium in our model and elements of this pathway including IL-33 can provide novel therapeutics in inflammatory neuropathies. PMID:27208700

  3. Trans-activity of Plasma Membrane-associated Ganglioside Sialyltransferase in Mammalian Cells*

    PubMed Central

    Vilcaes, Aldo A.; Demichelis, Vanina Torres; Daniotti, Jose L.

    2011-01-01

    Gangliosides are acidic glycosphingolipids that contain sialic acid residues and are expressed in nearly all vertebrate cells. They are synthesized at the Golgi complex by a combination of glycosyltransferase activities followed by vesicular delivery to the plasma membrane, where they participate in a variety of physiological as well as pathological processes. Recently, a number of enzymes of ganglioside anabolism and catabolism have been shown to be associated with the plasma membrane. In particular, it was observed that CMP-NeuAc:GM3 sialyltransferase (Sial-T2) is able to sialylate GM3 at the plasma membrane (cis-catalytic activity). In this work, we demonstrated that plasma membrane-integrated ecto-Sial-T2 also displays a trans-catalytic activity at the cell surface of epithelial and melanoma cells. By using a highly sensitive enzyme-linked immunosorbent assay combined with confocal fluorescence microscopy, we observed that ecto-Sial-T2 was able to sialylate hydrophobically or covalently immobilized GM3 onto a solid surface. More interestingly, we observed that ecto-Sial-T2 was able to sialylate GM3 exposed on the membrane of neighboring cells by using both the exogenous and endogenous donor substrate (CMP-N-acetylneuraminic acid) available at the extracellular milieu. In addition, the trans-activity of ecto-Sial-T2 was considerably reduced when the expression of the acceptor substrate was inhibited by using a specific inhibitor of biosynthesis of glycolipids, indicating the lipidic nature of the acceptor. Our findings provide the first direct evidence that an ecto-sialyltransferase is able to trans-sialylate substrates exposed in the plasma membrane from mammalian cells, which represents a novel insight into the molecular events that regulate the local glycosphingolipid composition. PMID:21768099

  4. Peptides mimicking GD2 ganglioside elicit cellular, humoral and tumor-protective immune responses in mice

    PubMed Central

    Wondimu, Assefa; Zhang, Tianqian; Kieber-Emmons, Thomas; Gimotty, Phyllis; Sproesser, Katrin; Somasundaram, Rajasekharan; Ferrone, Soldano; Tsao, Chun-Yen

    2012-01-01

    Introduction Because of its restricted distribution in normal tissues and its high expression on tumors of neuroectodermal origin, GD2 ganglioside is an excellent target for active specific immunotherapy. However, GD2 usually elicits low-titered IgM and no IgG or cellular immune responses, limiting its usefulness as a vaccine for cancer patients. We have previously shown that anti-idiotypic monoclonal antibody mimics of GD2 can induce antigen-specific humoral and cellular immunity in mice, but inhibition of tumor growth by the mimics could not be detected. Methods and results Here, we isolated two peptides from phage display peptide libraries by panning with GD2-specific mAb ME361. The peptides inhibited binding of the mAb to GD2. When coupled to keyhole limpet hemocyanin (KLH) or presented as multiantigenic peptides in QS21 adjuvant, the peptides induced in mice antibodies binding specifically to GD2 and delayed-type hypersensitive lymphocytes reactive specifically with GD2-positive D142.34 mouse melanoma cells. Induction of delayed-type hypersensitivity (DTH) reaction was dependent on CD4-positive lymphocytes. The immunity elicited by the peptides significantly inhibited growth of GD2-positive melanoma cells in mice. Conclusion Our study suggests that immunization with peptides mimicking GD2 ganglioside inhibits tumor growth through antibody and/or CD4-positive T cell-mediated mechanisms. Cytolytic T lymphocytes most likely do not play a role. Our results provide the basis for structural analysis of carbohydrate mimicry by peptides. PMID:18157673

  5. Composition of gangliosides and neutral glycosphingolipids of brain in classical Tay-Sachs and Sandhoff disease: more lyso-GM2 in Sandhoff disease?

    PubMed

    Rosengren, B; Månsson, J E; Svennerholm, L

    1987-09-01

    The ganglioside composition of the brain from an individual with classical Tay-Sachs disease and from an individual with Sandhoff disease was examined using our new quantitative methods for ganglioside content determination and compared with that of age-matched control brains. The concentration of GM2 was found to be 12.2 and 13.0 mumol/g of fresh tissue in Tay-Sachs disease and in Sandhoff disease cerebral gray matter, respectively. GM2 was 86 and 87% respectively, of total gangliosides. The concentration of GM1 and, in particular, GM3 ganglioside was also found to be increased, whereas the concentration of the major di- and trisialogangliosides (GD1a, GD1b, and GT1b) had diminished markedly. There was no significant increase in level of any other ganglioside than lyso-GM2. Its concentration was 12 and 16 nmol/g in cerebral gray matter of two Tay-Sachs disease brains and 43 nmol/g in Sandhoff disease brain. The Sandhoff disease brain also differed from the classical Tay-Sachs disease brain by having a much higher concentration of gangliotriaosylceramide and globotetraosylceramide. The structures of relevant gangliosides and neutral glycolipids were established by fast atom bombardment-mass spectrometry and permethylation studies.

  6. Electrokinetic and electrostatic properties of bilayers containing gangliosides GM1, GD1a, or GT1. Comparison with a nonlinear theory.

    PubMed Central

    McDaniel, R V; Sharp, K; Brooks, D; McLaughlin, A C; Winiski, A P; Cafiso, D; McLaughlin, S

    1986-01-01

    We formed vesicles from mixtures of egg phosphatidylcholine (PC) and the gangliosides GM1, GD1a, or GT1 to model the electrokinetic properties of biological membranes. The electrophoretic mobilities of the vesicles are similar in NaCl, CsCl, and TMACl solutions, suggesting that monovalent cations do not bind significantly to these gangliosides. If we assume the sialic acid groups on the gangliosides are located some distance from the surface of the vesicle and the sugar moieties exert hydrodynamic drag, we can describe the mobility data in 1, 10, and 100 mM monovalent salt solutions with a combination of the Navier-Stokes and nonlinear Poisson-Boltzmann equations. The values we assume for the thickness of the ganglioside head group and the location of the charge affect the theoretical predictions markedly, but the Stokes radius of each sugar and the location of the hydrodynamic shear plane do not. We obtain a reasonable fit to the mobility data by assuming that all ganglioside head groups project 2.5 nm from the bilayer and all fixed charges are in a plane 1 nm from the bilayer surface. We tested the latter assumption by estimating the surface potentials of PC/ganglioside bilayers using four techniques: we made 31P nuclear magnetic resonance, fluorescence, electron spin resonance, and conductance measurements. The results are qualitatively consistent with our assumption. PMID:3697476

  7. Synthesis and characterization of N-parinaroyl analogs of ganglioside GM3 and de-N-acetyl GM3. Interactions with the EGF receptor kinase

    NASA Technical Reports Server (NTRS)

    Song, W.; Welti, R.; Hafner-Strauss, S.; Rintoul, D. A.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    A specific plasma membrane glycosphingolipid, known as ganglioside GM3, can regulate the intrinsic tyrosyl kinase activity of the epidermal growth factor (EGF) receptor; this modulation is not associated with alterations in hormone binding to the receptor. GM3 inhibits EGF receptor tyrosyl kinase activity in detergent micelles, in plasma membrane vesicles, and in whole cells. In addition, immunoaffinity-purified EGF receptor preparations contain ganglioside GM3 (Hanai et al. (1988) J. Biol. Chem. 263, 10915-10921), implying that the glycosphingolipid is intimately associated with the receptor kinase in cell membranes. Both the nature of this association and the molecular mechanism of kinase inhibition remain to be elucidated. In this report, we describe the synthesis of a fluorescent analog of ganglioside GM3, in which the native fatty acid was replaced with trans-parinaric acid. This glycosphingolipid inhibited the receptor kinase activity in a manner similar to that of the native ganglioside. A modified fluorescent glycosphingolipid, N-trans-parinaroyl de-N-acetyl ganglioside GM3, was also prepared. This analog, like the nonfluorescent de-N-acetyl ganglioside GM3, had no effect on receptor kinase activity. Results from tryptophan fluorescence quenching and steady-state anisotropy measurements in membranes containing these fluorescent probes and the human EGF receptor were consistent with the notion that GM3, but not de-N-acetyl GM3, interacts specifically with the receptor in intact membranes.

  8. DNA vaccine expressing the mimotope of GD2 ganglioside induces protective GD2 cross-reactive antibody responses.

    PubMed

    Bolesta, Elizabeth; Kowalczyk, Aleksandra; Wierzbicki, Andrzej; Rotkiewicz, Piotr; Bambach, Barbara; Tsao, Chun-Yen; Horwacik, Irena; Kolinski, Andrzej; Rokita, Hanna; Brecher, Martin; Wang, Xinhui; Ferrone, Soldano; Kozbor, Danuta

    2005-04-15

    The GD2 ganglioside expressed on neuroectodermally derived tumors, including neuroblastoma and melanoma, is weakly immunogenic in tumor-bearing patients and induces predominantly immunoglobulin (Ig)-M antibody responses in the immunized host. Here, we investigated whether interconversion of GD2 into a peptide mimetic form would induce GD2 cross-reactive IgG antibody responses in mice. Screening of the X(15) phage display peptide library with the anti-GD2 monoclonal antibody (mAb) 14G2a led to isolation of mimetic peptide 47, which inhibited the binding of 14G2a antibody to GD2-positive tumor cells. The peptide was also recognized by GD2-specific serum antibodies from a patient with neuroblastoma, suggesting that it bears an internal image of GD2 ganglioside expressed on the tumor cells. The molecular basis for antigenicity of the GD2 mimetic peptide, established by molecular modeling and mutagenesis studies, led to the generation of a 47-LDA mutant with an increased mimicry to GD2. Immunization of mice with peptide 47-LDA-encoded plasmid DNA elicited GD2 cross-reactive IgG antibody responses, which were increased on subsequent boost with GD2 ganglioside. The vaccine-induced antibodies recognized GD2-positive tumor cells, mediated complement-dependent cytotoxicity, and exhibited protection against s.c. human GD2-positive melanoma growth in the severe combined immunodeficient mouse xenograft model. The results from our studies provide insights into approaches for boosting GD2 cross-reactive IgG antibody responses by minigene vaccination with a protective epitope of GD2 ganglioside.

  9. Sialic Acids in the Brain: Gangliosides and Polysialic Acid in Nervous System Development, Stability, Disease, and Regeneration

    PubMed Central

    Gerardy-Schahn, Rita; Hildebrandt, Herbert

    2014-01-01

    Every cell in nature carries a rich surface coat of glycans, its glycocalyx, which constitutes the cell's interface with its environment. In eukaryotes, the glycocalyx is composed of glycolipids, glycoproteins, and proteoglycans, the compositions of which vary among different tissues and cell types. Many of the linear and branched glycans on cell surface glycoproteins and glycolipids of vertebrates are terminated with sialic acids, nine-carbon sugars with a carboxylic acid, a glycerol side-chain, and an N-acyl group that, along with their display at the outmost end of cell surface glycans, provide for varied molecular interactions. Among their functions, sialic acids regulate cell-cell interactions, modulate the activities of their glycoprotein and glycolipid scaffolds as well as other cell surface molecules, and are receptors for pathogens and toxins. In the brain, two families of sialoglycans are of particular interest: gangliosides and polysialic acid. Gangliosides, sialylated glycosphingolipids, are the most abundant sialoglycans of nerve cells. Mouse genetic studies and human disorders of ganglioside metabolism implicate gangliosides in axon-myelin interactions, axon stability, axon regeneration, and the modulation of nerve cell excitability. Polysialic acid is a unique homopolymer that reaches >90 sialic acid residues attached to select glycoproteins, especially the neural cell adhesion molecule in the brain. Molecular, cellular, and genetic studies implicate polysialic acid in the control of cell-cell and cell-matrix interactions, intermolecular interactions at cell surfaces, and interactions with other molecules in the cellular environment. Polysialic acid is essential for appropriate brain development, and polymorphisms in the human genes responsible for polysialic acid biosynthesis are associated with psychiatric disorders including schizophrenia, autism, and bipolar disorder. Polysialic acid also appears to play a role in adult brain plasticity

  10. DNA vaccine expressing the mimotope of GD2 ganglioside induces protective GD2 cross-reactive antibody responses.

    PubMed

    Bolesta, Elizabeth; Kowalczyk, Aleksandra; Wierzbicki, Andrzej; Rotkiewicz, Piotr; Bambach, Barbara; Tsao, Chun-Yen; Horwacik, Irena; Kolinski, Andrzej; Rokita, Hanna; Brecher, Martin; Wang, Xinhui; Ferrone, Soldano; Kozbor, Danuta

    2005-04-15

    The GD2 ganglioside expressed on neuroectodermally derived tumors, including neuroblastoma and melanoma, is weakly immunogenic in tumor-bearing patients and induces predominantly immunoglobulin (Ig)-M antibody responses in the immunized host. Here, we investigated whether interconversion of GD2 into a peptide mimetic form would induce GD2 cross-reactive IgG antibody responses in mice. Screening of the X(15) phage display peptide library with the anti-GD2 monoclonal antibody (mAb) 14G2a led to isolation of mimetic peptide 47, which inhibited the binding of 14G2a antibody to GD2-positive tumor cells. The peptide was also recognized by GD2-specific serum antibodies from a patient with neuroblastoma, suggesting that it bears an internal image of GD2 ganglioside expressed on the tumor cells. The molecular basis for antigenicity of the GD2 mimetic peptide, established by molecular modeling and mutagenesis studies, led to the generation of a 47-LDA mutant with an increased mimicry to GD2. Immunization of mice with peptide 47-LDA-encoded plasmid DNA elicited GD2 cross-reactive IgG antibody responses, which were increased on subsequent boost with GD2 ganglioside. The vaccine-induced antibodies recognized GD2-positive tumor cells, mediated complement-dependent cytotoxicity, and exhibited protection against s.c. human GD2-positive melanoma growth in the severe combined immunodeficient mouse xenograft model. The results from our studies provide insights into approaches for boosting GD2 cross-reactive IgG antibody responses by minigene vaccination with a protective epitope of GD2 ganglioside. PMID:15833876

  11. Database and data analysis application for structural characterization of gangliosides and sulfated glycosphingolipids by negative ion mass spectrometry.

    PubMed

    Rožman, Marko; Fabris, Dragana; Mrla, Tomislav; Vukelić, Zeljka

    2014-12-01

    Gangliosides and sulfated glycosphingolipids, as building and functional components of animal cell membranes, participate in cell-to-cell interactions and signaling, but also in changes of cell architecture due to different pathophysiological events. In order to enable higher throughput and to facilitate structural characterization of gangliosides/sulfo-glycosphingolipids (GSL) and their neutral GSL counterparts by negative ion mass spectrometry (MS) and tandem MS techniques, a database and data analysis application have been developed. In silico developed glycosphingolipid database considers a high diversity of ceramide compositions, several sialic acid types (N-acetylneuraminic acid, N-glycolylneuraminic acid and 2-keto-3-deoxynononic acid) as well as possible additional substitutions/modifications of glycosphingolipids, such as O-acetylation, de-N-acetylation, fucosylation, glucuronosylation, sulfation, attachment of repeating terminal hexose-N-acetylhexosamine- (Hex-HexNAc-)1-6 extension, and possible lactone forms. Data analysis application, named GSL-finder, enables correlation of negative ion MS and/or low-energy tandem MS spectra with the database structures. The GSL-database construction and the GSL-finder application searching rules are explained. Validation conducted on GD1a fraction as well as on complex mixtures of native gangliosides isolated from different mammalian brain tissues (human fetal and adult brain, and calf brain tissue) demonstrated agreement with previous studies. Plain, fast, and automated routine for structural characterization of gangliosides/sulfated glycosphingolipids and their neutral GSL counterparts described here could facilitate and improve mass spectrometric analysis of complex glycosphingolipid mixtures originating from variety of normal and pathological biomaterial, where it is known that distinctive changes in glycosphingolipid composition occur.

  12. Heterogeneity of detergent-insoluble membranes from human intestine containing caveolin-1 and ganglioside G(M1).

    PubMed

    Badizadegan, K; Dickinson, B L; Wheeler, H E; Blumberg, R S; Holmes, R K; Lencer, W I

    2000-06-01

    In intestinal epithelia, cholera and related toxins elicit a cAMP-dependent chloride secretory response fundamental to the pathogenesis of toxigenic diarrhea. We recently proposed that specificity of cholera toxin (CT) action in model intestinal epithelia may depend on the toxin's cell surface receptor ganglioside G(M1). Binding G(M1) enabled the toxin to elicit a response, but forcing the toxin to enter the cell by binding the closely related ganglioside G(D1a) rendered the toxin inactive. The specificity of ganglioside function correlated with the ability of G(M1) to partition CT into detergent-insoluble glycosphingolipid-rich membranes (DIGs). To test the biological plausibility of these hypotheses, we examined native human intestinal epithelia. We show that human small intestinal epithelia contain DIGs that distinguish between toxin bound to G(M1) and G(D1a), thus providing a possible mechanism for enterotoxicity associated with CT. We find direct evidence for the presence of caveolin-1 in DIGs from human intestinal epithelia but find that these membranes are heterogeneous and that caveolin-1 is not a structural component of apical membrane DIGs that contain CT.

  13. Construction of a hybrid β-hexosaminidase subunit capable of forming stable homodimers that hydrolyze GM2 ganglioside in vivo

    PubMed Central

    Tropak, Michael B; Yonekawa, Sayuri; Karumuthil-Melethil, Subha; Thompson, Patrick; Wakarchuk, Warren; Gray, Steven J; Walia, Jagdeep S; Mark, Brian L; Mahuran, Don

    2016-01-01

    Tay-Sachs or Sandhoff disease result from mutations in either the evolutionarily related HEXA or HEXB genes encoding respectively, the α- or β-subunits of β-hexosaminidase A (HexA). Of the three Hex isozymes, only HexA can interact with its cofactor, the GM2 activator protein (GM2AP), and hydrolyze GM2 ganglioside. A major impediment to establishing gene or enzyme replacement therapy based on HexA is the need to synthesize both subunits. Thus, we combined the critical features of both α- and β-subunits into a single hybrid µ-subunit that contains the α-subunit active site, the stable β-subunit interface and unique areas in each subunit needed to interact with GM2AP. To facilitate intracellular analysis and the purification of the µ-homodimer (HexM), CRISPR-based genome editing was used to disrupt the HEXA and HEXB genes in a Human Embryonic Kidney 293 cell line stably expressing the µ-subunit. In association with GM2AP, HexM was shown to hydrolyze a fluorescent GM2 ganglioside derivative both in cellulo and in vitro. Gene transfer studies in both Tay-Sachs and Sandhoff mouse models demonstrated that HexM expression reduced brain GM2 ganglioside levels. PMID:26966698

  14. Construction of a hybrid β-hexosaminidase subunit capable of forming stable homodimers that hydrolyze GM2 ganglioside in vivo.

    PubMed

    Tropak, Michael B; Yonekawa, Sayuri; Karumuthil-Melethil, Subha; Thompson, Patrick; Wakarchuk, Warren; Gray, Steven J; Walia, Jagdeep S; Mark, Brian L; Mahuran, Don

    2016-01-01

    Tay-Sachs or Sandhoff disease result from mutations in either the evolutionarily related HEXA or HEXB genes encoding respectively, the α- or β-subunits of β-hexosaminidase A (HexA). Of the three Hex isozymes, only HexA can interact with its cofactor, the GM2 activator protein (GM2AP), and hydrolyze GM2 ganglioside. A major impediment to establishing gene or enzyme replacement therapy based on HexA is the need to synthesize both subunits. Thus, we combined the critical features of both α- and β-subunits into a single hybrid µ-subunit that contains the α-subunit active site, the stable β-subunit interface and unique areas in each subunit needed to interact with GM2AP. To facilitate intracellular analysis and the purification of the µ-homodimer (HexM), CRISPR-based genome editing was used to disrupt the HEXA and HEXB genes in a Human Embryonic Kidney 293 cell line stably expressing the µ-subunit. In association with GM2AP, HexM was shown to hydrolyze a fluorescent GM2 ganglioside derivative both in cellulo and in vitro. Gene transfer studies in both Tay-Sachs and Sandhoff mouse models demonstrated that HexM expression reduced brain GM2 ganglioside levels. PMID:26966698

  15. Expression of B4GALNT1, an essential glycosyltransferase for the synthesis of complex gangliosides, suppresses BACE1 degradation and modulates APP processing

    PubMed Central

    Yamaguchi, Tokiaki; Yamauchi, Yoshio; Furukawa, Keiko; Ohmi, Yuhsuke; Ohkawa, Yuki; Zhang, Qing; Okajima, Tetsuya; Furukawa, Koichi

    2016-01-01

    Alzheimer’s disease (AD) is the most prevalent form of dementia characterized by the extracellular accumulation of amyloid β (Aβ) peptides, which are produced by proteolytic cleavages of amyloid precursor protein (APP). Gangliosides are involved in AD pathophysiology including Aβ deposition and APP processing, yet the detailed mechanisms are not fully understood. Here we examined how changes in the carbohydrate moiety of gangliosides alter APP processing in human melanoma cells, neuroectoderm-derived cells. We showed that forced expression of GD2, GM2 or GM1 (by introducing B4GALNT1 cDNA into cells not expressing this glycosyltransferase) results in increases of α- and β-site cleavages of APP with a prominent increase in β-cleavage. We also showed that β-site APP cleaving enzyme 1 (BACE1) protein is highly protected from the degradation in cells expressing these gangliosides, thereby increasing the expression of this protein. Unexpectedly, adding gangliosides exogenously altered neither BACE1 levels nor β-site cleavage. The stabilisation of BACE1 protein led to the increase of this protein in lipid rafts, where BACE1 processes APP. Based on the current results, we propose a hitherto undisclosed link between ganglioside expression and AD; the expression of B4GALNT1 positively regulates the β-site cleavage by mainly inhibiting the lysosomal degradation of BACE1 protein. PMID:27687691

  16. The first total synthesis of ganglioside GalNAc-GD1a, a target molecule for autoantibodies in Guillain-Barré syndrome.

    PubMed

    Fujikawa, Kohki; Nakashima, Shinya; Konishi, Miku; Fuse, Tomoaki; Komura, Naoko; Ando, Takayuki; Ando, Hiromune; Yuki, Nobuhiro; Ishida, Hideharu; Kiso, Makoto

    2011-05-01

    The first synthesis of ganglioside GalNAc-GD1a, featuring efficient glycan assembly and a cyclic glucosyl ceramide as a versatile unit for ganglioside synthesis is described. Although ganglioside GalNAc-GD1a was first found as a brain ganglioside, IgG autoantibodies to GalNAc-GD1a were subsequently found to be closely related to a human peripheral-nerve disorder, Guillain-Barré syndrome, which is the commonest cause of acute flaccid paralysis worldwide. In this study, the characteristic hexasaccharide part carrying two sialic acid residues was synthesized efficiently by use of a readily accessible GM2-core unit as a common unit. The potentially difficult coupling of the oligosaccharide and ceramide moieties was carried out by using a cyclic glucosyl ceramide as a coupling partner for the hexasaccharide part, thereby successfully providing the framework of the target compound. Global deprotection delivered the homogenous ganglioside GalNAc-GD1a. An enzyme-linked immunosorbent assay showed that sera from patients with Guillain-Barré syndrome reacted both with natural and with synthetic GalNAc-GD1a.

  17. The first total synthesis of ganglioside GalNAc-GD1a, a target molecule for autoantibodies in Guillain-Barré syndrome.

    PubMed

    Fujikawa, Kohki; Nakashima, Shinya; Konishi, Miku; Fuse, Tomoaki; Komura, Naoko; Ando, Takayuki; Ando, Hiromune; Yuki, Nobuhiro; Ishida, Hideharu; Kiso, Makoto

    2011-05-01

    The first synthesis of ganglioside GalNAc-GD1a, featuring efficient glycan assembly and a cyclic glucosyl ceramide as a versatile unit for ganglioside synthesis is described. Although ganglioside GalNAc-GD1a was first found as a brain ganglioside, IgG autoantibodies to GalNAc-GD1a were subsequently found to be closely related to a human peripheral-nerve disorder, Guillain-Barré syndrome, which is the commonest cause of acute flaccid paralysis worldwide. In this study, the characteristic hexasaccharide part carrying two sialic acid residues was synthesized efficiently by use of a readily accessible GM2-core unit as a common unit. The potentially difficult coupling of the oligosaccharide and ceramide moieties was carried out by using a cyclic glucosyl ceramide as a coupling partner for the hexasaccharide part, thereby successfully providing the framework of the target compound. Global deprotection delivered the homogenous ganglioside GalNAc-GD1a. An enzyme-linked immunosorbent assay showed that sera from patients with Guillain-Barré syndrome reacted both with natural and with synthetic GalNAc-GD1a. PMID:21469228

  18. Evaluation of a ganglioside immunosorbent assay for detection of Escherichia coli heat-labile enterotoxin.

    PubMed

    Bäck, E; Svennerholm, A M; Holmgren, J; Möllby, R

    1979-12-01

    The GM1 ganglioside enzyme-linked immunosorbent assay (GM1-ELISA), an immunological method for detection of Escherichia coli heat-labile enterotoxin (LT), was quantitatively and qualitatively compared with the conventional adrenal cell test for the identification of LT-producing strains. A micromodification model of the assay was developed. Enterotoxin preparations from 120 E. coli isolates from individuals with diarrhea, which had been previously shown to be enterotoxigenic by the adrenal cell test, and from 44 control strains of E. coli were compared in parallel by the two methods. Quantitatively the covariation of the enterotoxin titers was highly significant (RS = 0.98, P less than 0.001), the GM1-ELISA being somewhat more sensitive than the adrenal cell test. The methodological error was less than 5% in both tests. Qualitatively the overall agreement for positive and negative reactions for the two methods was 89%. The GM1-ELISA is practical for routine use in the diagnosis of enterotoxigenic E. coli, especially in laboratories without facilities for cell culture.

  19. Effects of ganglioside GM1 and neural growth factor on neural stem cell proliferation and differentiation.

    PubMed

    Wang, Q; Song, Y H; Tang, Z; Wang, Z P; Xu, Q; Bao, N

    2016-01-01

    Neurogenesis, recovery from nerve injury, neurodegeneration, and Parkinson's disease affect people's health, yet the underlying molecular mechanisms remain elusive. Here, we investigated the effect of ganglioside GM1 and neural growth factor (NGF) on neural stem cell (NSC) proliferation and differentiation in vitro to provide a scientific basis for comprehensive treatment of nervous system diseases via NSC application. As widely applied methods of relatively high accuracy, cell counts and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assays were used to assess NSC proliferation. In addition, western blotting was employed to determine NSC differentiation. Cell counts and MTT assays demonstrated that in epidermal growth factor (EGF)- and basic fibroblast growth factor (bFGF)-containing medium, a high concentration of GM1, but not NGF, significantly elevated NSC proliferation. In NSC cultures lacking EGF and bFGF, cell counts and MTT values were significantly increased compared to those in the negative control group on days 4, 7, and 10 after GM1 (25, 100, and 200 ng/mL) but not NGF (25, 50, 100, and 200 ng/mL) treatment. Western blotting revealed significantly increased expression of nestin (an NSC marker) in NSCs treated with GM1, and upregulation of glial fibrillary acidic protein (a glial cell marker) and neuron-specific enolase (a neuron marker) in those administered NGF. Our results suggest that GM1 and NGF induce NSC proliferation and differentiation, respectively, in a dose-dependent manner. PMID:27525911

  20. An animal model of pain produced by systemic administration of an immunotherapeutic anti-ganglioside antibody.

    PubMed

    Slart, R; Yu, A L; Yaksh, T L; Sorkin, L S

    1997-01-01

    For the management of pediatric neuroblastoma, a promising experimental treatment includes slow systemic infusion of a human/ mouse chimeric monoclonal antibody against the GD2 ganglioside. Beneficial actions are however, accompanied by severe pain and altered cardiovascular tone. The pain is conventionally controllable with moderate to relatively high doses of intravenous morphine. An animal model was established to examine the change in nociceptive threshold produced by anti-GD2-antibody. Rats given bolus injections of antibody through an in-dwelling jugular catheter developed a quantifiable mechanical allodynia. At higher doses, allodynia and touch evoked agitation began within the first 15-min test interval, was maximal within the first hour, and for some doses was still present, although greatly reduced at 24 and 48 h. Rapid administration of antibody led to an increase in mean resting blood pressure of 12 mmHg +/- 1.8 (P < or = 0.02) and the development of a prolonged cardiovascular response to an otherwise innocuous stimulus. These observations demonstrate that the pain associated with monoclonal antibody treatment can be modeled in animals. This approach has potential for defining the pharmacology of the allodynia and ways in which the pain state may be ameliorated.

  1. Bis(monoacylglycero)phosphate and ganglioside GM1 spontaneously form small homogeneous vesicles at specific concentrations

    SciTech Connect

    Chebukati, Janetricks N.; Goff, Philip C.; Frederick, Thomas E.; Fanucci, Gail E.

    2010-04-09

    The morphology and size of hydrated lipid dispersions of bis(monoacylglycero)phosphate (BMP) mixed with varying mole percentages of the ganglioside GM1 were investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Electron paramagnetic resonance (EPR) spectroscopy of these same mixtures, doped at 0.5 mol% with doxyl labeled lipids, was used to investigate acyl-chain packing. Results show that for 20-30% GM1, hydrated BMP:GM1 mixtures spontaneously form small spherical vesicles with diameters {approx}100 nm and a narrow size distribution profile. For other concentrations of GM1, hydrated dispersions with BMP have non-spherical shapes and heterogeneous size profiles, with average vesicle diameters >400 nm. All samples were prepared at pH 5.5 to mimic the lumen acidity of the late endosome where BMP is an essential component of intraendosomal vesicle budding, lipid sorting and trafficking. These findings indicate that GM1 and BMP under a limited concentration range spontaneously form small vesicles of homogeneous size in an energy independent manner without the need of protein templating. Because BMP is essential for intraendosomal vesicle formation, these results imply that lipid-lipid interactions may play a critical role in the endosomal process of lipid sorting and trafficking.

  2. Structural basis of GM1 ganglioside recognition by simian virus 40.

    PubMed

    Neu, Ursula; Woellner, Karin; Gauglitz, Guenter; Stehle, Thilo

    2008-04-01

    Simian virus 40 (SV40) has been a paradigm for understanding attachment and entry of nonenveloped viruses, viral DNA replication, and virus assembly, as well as for endocytosis pathways associated with caveolin and cholesterol. We find by glycan array screening that SV40 recognizes its ganglioside receptor GM1 with a quite narrow specificity, but isothermal titration calorimetry shows that individual binding sites have a relatively low affinity, with a millimolar dissociation constant. The high-resolution crystal structure of recombinantly produced SV40 capsid protein, VP1, in complex with the carbohydrate portion of GM1, reveals that the receptor is bound in a shallow solvent-exposed groove at the outer surface of the capsid. Through a complex network of interactions, VP1 recognizes a conformation of GM1 that is the dominant one in solution. Analysis of contacts provides a structural basis for the observed specificity and suggests binding mechanisms for additional physiologically relevant GM1 variants. Comparison with murine Polyomavirus (Polyoma) receptor complexes reveals that SV40 uses a different mechanism of sialic acid binding, which has implications for receptor binding of human polyomaviruses. The SV40-GM1 complex reveals a parallel to cholera toxin, which uses a similar cell entry pathway and binds GM1 in the same conformation.

  3. Effects of Methylprednisolone And Ganglioside GM-1 on a Spinal Lesion: A Functional Analysis

    PubMed Central

    Carvalho, Márcio Oliveira Penna; de Barros Filho, Tarcisio Eloy Pessoa; Tebet, Marcos Antonio

    2008-01-01

    OBJECTIVES The pharmacological effects of methylprednisolone (MP) and ganglioside GM-1 on spinal injuries have been thoroughly investigated, but only a few studies have evaluated the interaction between these two drugs. METHODS Twenty-four Wistar rats were subjected to contusive injury of the spinal cord produced by the NYU system. These animals were divided into four groups: group I was injected with MP; group II was injected with GM-1; group III was injected with MP together with GM-1; and group control received physiological serum. The animals were evaluated with regard to their recovery of locomotive function by means of the BBB test on the second, seventh and fourteenth days after receiving the contusive injury to the spinal cord. They were sacrificed on the fourteenth day. RESULTS This study demonstrated that the MP and GM-1 groups presented functional results that were better than those of the control group, although the enhanced recovery of group II (GM-1) relative to the control group was not statistically significant (p>0.05). The most notable recovery of locomotive function was observed in the group that received MP alone (p<0.05). The group that received MP together with GM-1 presented results that were better than those of the control group (p<0.05). CONCLUSION Administration of methylprednisolone alone or with GM-1 was shown to be effective for recovery of locomotive function. Combined administration of these drugs resulted in better outcomes than administration of methylprednisolone alone. PMID:18568249

  4. [Serum IgG antibodies to GD1a and GM1 gangliosides in elderly people].

    PubMed

    Kolyovska, V

    2016-01-01

    Nowadays, the percentage of elderly people in society grows. Good nutrition and medical care help older people to have a normal life over 80 to 90 years. In the last ten years it is of critical importance to establish the clinical significance of serum IgG anti-GD1a and anti-GM1 ganglioside antibodies as potential biomarkers for neuronal damage in neurodegenerative diseases and immune-mediated neuropathies and demyelination. In the current study, the diagnostic values of IgG anti-GD1a and anti-GM1 antibodies were determined by the ELISA method in serum samples of 18 elderly patients (71-91 years). Significantly elevated serum IgG anti-GD1a and anti-GM1 antibodies titers were detected only in patients over 80 years. These data suggest that the immune-mediated neuropathies, neurodegeneration and demyelination in healthy elderly occur after 80 years old. Therefore, IgG anti-GD1a and anti-GM1 antibodies can serve as biomarkers, showing the nervous system dysfunction. PMID:26973195

  5. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity[S

    PubMed Central

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-01-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids. PMID:26175473

  6. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity.

    PubMed

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-09-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids. PMID:26175473

  7. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity.

    PubMed

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-09-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids.

  8. Design, Synthesis, and Biological Evaluation of Ganglioside Hp-s1 Analogues Varying at Glucosyl Moiety.

    PubMed

    Hung, Jung-Tung; Yeh, Chun-Hong; Yang, Shih-An; Lin, Chiu-Ya; Tai, Hung-Ju; Shelke, Ganesh B; Reddy, Daggula Mallikarjuna; Yu, Alice L; Luo, Shun-Yuan

    2016-08-17

    Ganglioside Hp-s1 is isolated from the ovary of sea urchin Diadema setosum. It exhibited better neuritogenic activity than GM1 in pheochromocytoma 12 cells. To explore the roles of glucosyl moiety of Hp-s1 in contributing to the neurogenic activity, we developed feasible procedures for synthesis of Hp-s1 analogues (2a-2f). The glucosyl moiety of Hp-s1 was replaced with α-glucose, α-galactose, β-galactose, α-mannose, and β-mannose, and their biological activities on SH-SY5Y cells and natural killer T (NKT) cells were evaluated. We found that the orientation of C-2 hydroxyl group at glucosyl moiety of Hp-s1 plays an important role to induce neurite outgrowth of SH-SY5Y cells. Surprisingly, compound 2d could activate NKT cells to produce interleukin 2, although it did not show great activity on neurite outgrowth of SH-SY5Y cells. In general, the Hp-s1 might be considered as a lead compound for the development of novel drugs aimed at modulating the activity of neuronal cells. PMID:27276519

  9. Lyso-GM2 ganglioside: a possible biomarker of Tay-Sachs disease and Sandhoff disease.

    PubMed

    Kodama, Takashi; Togawa, Tadayasu; Tsukimura, Takahiro; Kawashima, Ikuo; Matsuoka, Kazuhiko; Kitakaze, Keisuke; Tsuji, Daisuke; Itoh, Kohji; Ishida, Yo-Ichi; Suzuki, Minoru; Suzuki, Toshihiro; Sakuraba, Hitoshi

    2011-01-01

    To find a new biomarker of Tay-Sachs disease and Sandhoff disease. The lyso-GM2 ganglioside (lyso-GM2) levels in the brain and plasma in Sandhoff mice were measured by means of high performance liquid chromatography and the effect of a modified hexosaminidase (Hex) B exhibiting Hex A-like activity was examined. Then, the lyso-GM2 concentrations in human plasma samples were determined. The lyso-GM2 levels in the brain and plasma in Sandhoff mice were apparently increased compared with those in wild-type mice, and they decreased on intracerebroventricular administration of the modified Hex B. The lyso-GM2 levels in plasma of patients with Tay-Sachs disease and Sandhoff disease were increased, and the increase in lyso-GM2 was associated with a decrease in Hex A activity. Lyso-GM2 is expected to be a potential biomarker of Tay-Sachs disease and Sandhoff disease. PMID:22205997

  10. Human monoclonal IgM with autoantibody activity against two gangliosides (GM1 and GD1b) in a patient with motor neuron syndrome.

    PubMed Central

    Jauberteau, M O; Gualde, N; Preud'Homme, J L; Rigaud, M; Gil, R; Vallat, J M; Baumann, N

    1990-01-01

    Small amounts of oligoclonal immunoglobulins were detected by Western blotting in the serum from a patient with motor neuron syndrome. The prominent one, a monoclonal IgM lambda, reacted strongly with the gangliosides GM1 and GD1b and more weakly with asialo GM1, as shown by immunoenzymatic staining of thin-layer chromatograms of gangliosides, ELISA on purified glycolipid coats and immunoadsorption with purified GM1. Affinity-chromatography with purified GM1 resulted in the purification of monoclonal IgM lambda. This purified IgM and its Fab fragments showed the same pattern of reactivity with gangliosides as that observed with whole serum. Such monoclonal IgM could be responsible for motor neuron diseases in some patients with overt or barely detectable monoclonal gammopathies. Images Fig. 2 Fig. 3 PMID:2357844

  11. Ganglioside GM2 mediates migration of tumor cells by interacting with integrin and modulating the downstream signaling pathway.

    PubMed

    Kundu, Manjari; Mahata, Barun; Banerjee, Avisek; Chakraborty, Sohini; Debnath, Shibjyoti; Ray, Sougata Sinha; Ghosh, Zhumur; Biswas, Kaushik

    2016-07-01

    The definitive role of ganglioside GM2 in mediating tumor-induced growth and progression is still unknown. Here we report a novel role of ganglioside GM2 in mediating tumor cell migration and uncovered its mechanism. Data shows differential expression levels of GM2-synthase as well as GM2 in different human cancer cells. siRNA mediated knockdown of GM2-synthase in CCF52, A549 and SK-RC-26B cells resulted in significant inhibition of tumor cell migration as well as invasion in vitro without affecting cellular proliferation. Over-expression of GM2-synthase in low-GM2 expressing SK-RC-45 cells resulted in a consequent increase in migration thus confirming the potential role GM2 and its downstream partners play in tumor cell migration and motility. Further, treatment of SK-RC-45 cells with exogenous GM2 resulted in a dramatic increase in migratory and invasive capacity with no change in proliferative capacity, thereby confirming the role of GM2 in tumorigenesis specifically by mediating tumor migration and invasion. Gene expression profiling of GM2-synthase silenced cells revealed altered expression of several genes involved in cell migration primarily those controlling the integrin mediated signaling. GM2-synthase knockdown resulted in decreased phosphorylation of FAK, Src as well as Erk, while over-expression and/or exogenous GM2 treatment caused increased FAK and Erk phosphorylation respectively. Again, GM2 mediated invasion and Erk phosphorylation is blocked in integrin knockdown SK-RC-45 cells, thus confirming that GM2 mediated migration and phosphorylation of Erk is integrin dependent. Finally, confocal microscopy suggested co-localization while co-immunoprecipitation and surface plasmon resonance (SPR) confirmed direct interaction of membrane bound ganglioside, GM2 with the integrin receptor. PMID:27066976

  12. Gangliosides inhibit bee venom melittin cytotoxicity but not phospholipase A{sub 2}-induced degranulation in mast cells

    SciTech Connect

    Nishikawa, Hirofumi; Kitani, Seiichi

    2011-05-01

    Sting accident by honeybee causes severe pain, inflammation and allergic reaction through IgE-mediated anaphylaxis. In addition to this hypersensitivity, an anaphylactoid reaction occurs by toxic effects even in a non-allergic person via cytolysis followed by similar clinical manifestations. Auto-injectable epinephrine might be effective for bee stings, but cannot inhibit mast cell lysis and degranulation by venom toxins. We used connective tissue type canine mast cell line (CM-MC) for finding an effective measure that might inhibit bee venom toxicity. We evaluated degranulation and cytotoxicity by measurement of {beta}-hexosaminidase release and MTT assay. Melittin and crude bee venom induced the degranulation and cytotoxicity, which were strongly inhibited by mono-sialoganglioside (G{sub M1}), di-sialoganglioside (G{sub D1a}) and tri-sialoganglioside (G{sub T1b}). In contrast, honeybee venom-derived phospholipase A{sub 2} induced the net degranulation directly without cytotoxicity, which was not inhibited by G{sub M1}, G{sub D1a} and G{sub T1b}. For analysis of distribution of G{alpha}{sub q} and G{alpha}{sub i} protein by western blotting, lipid rafts were isolated by using discontinuous sucrose gradient centrifuge. Melittin disrupted the localization of G{alpha}{sub q} and G{alpha}{sub i} at lipid raft, but gangliosides stabilized the rafts. As a result from this cell-based study, bee venom-induced anaphylactoid reaction can be explained with melittin cytotoxicity and phospholipase A{sub 2}-induced degranulation. Taken together, gangliosides inhibit the effect of melittin such as degranulation, cytotoxicity and lipid raft disruption but not phospholipase A{sub 2}-induced degranulation in mast cells. Our study shows a potential of gangliosides as a therapeutic tool for anaphylactoid reaction by honeybee sting.

  13. Ganglioside GM2 mediates migration of tumor cells by interacting with integrin and modulating the downstream signaling pathway.

    PubMed

    Kundu, Manjari; Mahata, Barun; Banerjee, Avisek; Chakraborty, Sohini; Debnath, Shibjyoti; Ray, Sougata Sinha; Ghosh, Zhumur; Biswas, Kaushik

    2016-07-01

    The definitive role of ganglioside GM2 in mediating tumor-induced growth and progression is still unknown. Here we report a novel role of ganglioside GM2 in mediating tumor cell migration and uncovered its mechanism. Data shows differential expression levels of GM2-synthase as well as GM2 in different human cancer cells. siRNA mediated knockdown of GM2-synthase in CCF52, A549 and SK-RC-26B cells resulted in significant inhibition of tumor cell migration as well as invasion in vitro without affecting cellular proliferation. Over-expression of GM2-synthase in low-GM2 expressing SK-RC-45 cells resulted in a consequent increase in migration thus confirming the potential role GM2 and its downstream partners play in tumor cell migration and motility. Further, treatment of SK-RC-45 cells with exogenous GM2 resulted in a dramatic increase in migratory and invasive capacity with no change in proliferative capacity, thereby confirming the role of GM2 in tumorigenesis specifically by mediating tumor migration and invasion. Gene expression profiling of GM2-synthase silenced cells revealed altered expression of several genes involved in cell migration primarily those controlling the integrin mediated signaling. GM2-synthase knockdown resulted in decreased phosphorylation of FAK, Src as well as Erk, while over-expression and/or exogenous GM2 treatment caused increased FAK and Erk phosphorylation respectively. Again, GM2 mediated invasion and Erk phosphorylation is blocked in integrin knockdown SK-RC-45 cells, thus confirming that GM2 mediated migration and phosphorylation of Erk is integrin dependent. Finally, confocal microscopy suggested co-localization while co-immunoprecipitation and surface plasmon resonance (SPR) confirmed direct interaction of membrane bound ganglioside, GM2 with the integrin receptor.

  14. Lysosomal dysfunction in a mouse model of Sandhoff disease leads to accumulation of ganglioside-bound amyloid-β peptide.

    PubMed

    Keilani, Serene; Lun, Yi; Stevens, Anthony C; Williams, Hadis N; Sjoberg, Eric R; Khanna, Richie; Valenzano, Kenneth J; Checler, Frederic; Buxbaum, Joseph D; Yanagisawa, Katsuhiko; Lockhart, David J; Wustman, Brandon A; Gandy, Sam

    2012-04-11

    Alterations in the lipid composition of endosomal-lysosomal membranes may constitute an early event in Alzheimer's disease (AD) pathogenesis. In this study, we investigated the possibility that GM2 ganglioside accumulation in a mouse model of Sandhoff disease might be associated with the accumulation of intraneuronal and extracellular proteins commonly observed in AD. Our results show intraneuronal accumulation of amyloid-β peptide (Aβ)-like, α-synuclein-like, and phospho-tau-like immunoreactivity in the brains of β-hexosaminidase knock-out (HEXB KO) mice. Biochemical and immunohistochemical analyses confirmed that at least some of the intraneuronal Aβ-like immunoreactivity (iAβ-LIR) represents amyloid precursor protein C-terminal fragments (APP-CTFs) and/or Aβ. In addition, we observed increased levels of Aβ40 and Aβ42 peptides in the lipid-associated fraction of HEXB KO mouse brains, and intraneuronal accumulation of ganglioside-bound Aβ (GAβ) immunoreactivity in a brain region-specific manner. Furthermore, α-synuclein and APP-CTFs and/or Aβ were found to accumulate in different regions of the substantia nigra, indicating different mechanisms of accumulation or turnover pathways. Based on the localization of the accumulated iAβ-LIR to endosomes, lysosomes, and autophagosomes, we conclude that a significant accumulation of iAβ-LIR may be associated with the lysosomal-autophagic turnover of Aβ and fragments of APP-containing Aβ epitopes. Importantly, intraneuronal GAβ immunoreactivity, a proposed prefibrillar aggregate found in AD, was found to accumulate throughout the frontal cortices of postmortem human GM1 gangliosidosis, Sandhoff disease, and Tay-Sachs disease brains. Together, these results establish an association between the accumulation of gangliosides, autophagic vacuoles, and the intraneuronal accumulation of proteins associated with AD. PMID:22496568

  15. Phospatidylserine or ganglioside--which of anionic lipids determines the effect of cationic dextran on lipid membrane?

    PubMed

    Hąc-Wydro, Katarzyna; Wydro, Paweł; Cetnar, Andrzej; Włodarczyk, Grzegorz

    2015-02-01

    In this work the influence of cationic polymer, namely diethylaminoethyl DEAE-dextran on model lipid membranes was investigated. This polymer is of a wide application as a biomaterial and a drug carrier and its cytotoxicity toward various cancer cells was also confirmed. It was suggested that anticancer effect of cationic dextran is connected with the binding of the polymer to the negatively charged sialic acid residues overexpressed in cancer membrane. This fact encouraged us to perform the studies aimed at verifying whether the effect of cationic DEAE-dextran on membrane is determined only by the presence of the negatively charged lipid in the system or the kind of anionic lipid is also important. To reach this goal systematic investigations on the effect of dextran on various one-component lipid monolayers and multicomponent hepatoma cell model membranes differing in the level and the kind of anionic lipids (phosphatidylserine, sialic acid-containing ganglioside GM3 or their mixture) were done. As evidenced the results the effect of DEAE-dextran on the model system is determined by anionic lipid-polymer electrostatic interactions. However, the magnitude of the effect of cationic polymer is strongly dependent on the kind of anionic lipid in the model system. Namely, the packing and ordering of the mixtures containing ganglioside GM3 were more affected by DEAE-dextran than phosphatidylserine-containing monolayers. Although the experiments were done on model systems and therefore further studies are highly needed, the collected data may indicate that ganglioside may be important in the differentiation of the effect of cationic dextran on membranes. PMID:25576813

  16. Therapeutic Strategies for Human IgM Antibodies Directed at Tumor-Associated Ganglioside Antigens: Discoveries Made During the Morton Era and Future Directions.

    PubMed

    Jones, Peter C; Irie, Reiko F

    2016-01-01

    Tumor-associated gangliosides have been investigated for their potential as antigenic targets for more than 35 years, culminating in the recent Food and Drug Administration approval of dinutuximab (Unituxin), an IgG antibody targeted against GD2, for the treatment of neuroblastoma in children. This review is focused on discoveries and development of therapeutic approaches involving human IgM antibodies directed against gangliosides, which occurred over the past 40 years at University of California-Los Angeles and the John Wayne Cancer Institute, where Dr. Donald Morton led the surgical oncology department until his death. PMID:27481004

  17. Free carrier absorption in self-activated PbWO4 and Ce-doped Y3(Al0.25Ga0.75)3O12 and Gd3Al2Ga3O12 garnet scintillators

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Korjik, M.; Lucchini, M. T.; Nargelas, S.; Sidletskiy, O.; Tamulaitis, G.; Tratsiak, Y.; Vaitkevičius, A.

    2016-08-01

    Nonequilibrium carrier dynamics in the scintillators prospective for fast timing in high energy physics and medical imaging applications was studied. The time-resolved free carrier absorption investigation was carried out to study the dynamics of nonequilibrium carriers in wide-band-gap scintillation materials: self-activated led tungstate (PbWO4, PWO) ant two garnet crystals, GAGG:Ce and YAGG:Ce. It was shown that free electrons appear in the conduction band of PWO and YAGG:Ce crystals within a sub-picosecond time scale, while the free holes in GAGG:Ce appear due to delocalization from Gd3+ ground states to the valence band within a few picoseconds after short-pulse excitation. The influence of Gd ions on the nonequilibrium carrier dynamics is discussed on the base of comparison the results of the free carrier absorption in GAGG:Ce containing gadolinium and in YAGG without Gd in the host lattice.

  18. Neoglycolipid analogues of ganglioside G sub M1 as functional receptors of cholera toxin

    SciTech Connect

    Pacuszka, T.; Bradley, R.M.; Fishman, P.H. )

    1991-03-12

    The authors synthesized several lipid analogues of ganglioside G{sub M1} by attaching its oligosaccharide moiety (G{sub M1}OS) to aminophospholipids, aliphatic amines, and cholesteryl hemisuccinate. They incubated G{sub M1}-deficient rat glioma C6 cells with each of the derivatives as well as native G{sub M1} and assayed the cells for their ability to bind and respond to cholera toxin. On the basis of the observed increase in binding of {sup 125}I-labeled cholera toxin, it was apparent that the cells took up and initially incorporated most of the derivatives into the plasma membrane. In the case of the aliphatic amine derivatives, the ability to generate new toxin binding sites was dependent on chain length; whereas the C{sub 10} derivative was ineffective, C{sub 12} and higher analogues were effective. Increased binding was dependent on both the concentration of the neoglycolipid in the medium and the time of exposure. Cells pretreated with the various derivatives accumulated cyclic AMP in response to cholera toxin, but there were differences in their effectiveness. The cholesterol and long-chain aliphatic amine derivatives were more effective than native G{sub M1}, whereas the phospholipid derivatives were less effective. The distance between G{sub M1}OS and the phospholipid also appeared to influence its functional activity. The results indicate that although G{sub M1}OS provides the recognition site for the binding of cholera toxin, the nature of the lipid moiety plays an important role in the action of the toxin.

  19. Protection against Experimental Stroke by Ganglioside GM1 Is Associated with the Inhibition of Autophagy

    PubMed Central

    Li, Li; Tian, Jinghua; Long, Mitchell King-Wei; Chen, Yong; Lu, Jianfei; Zhou, Changman; Wang, Tianlong

    2016-01-01

    Ganglioside GM1, which is particularly abundant in the central nervous system (CNS), is closely associated with the protection against several CNS disorders. However, controversial findings have been reported on the role of GM1 following ischemic stroke. In the present study, using a rat middle cerebral artery occlusion (MCAO) model, we investigated whether GM1 can protect against ischemic brain injury and whether it targets the autophagy pathway. GM1 was delivered to Sprague-Dawley male rats at 3 doses (25 mg/kg, 50 mg/kg, 100 mg/kg) by intraperitoneal injection soon after reperfusion and then once daily for 2 days. The same volume of saline was given as a control. Tat–Beclin-1, a specific autophagy inducer, was administered by intraperitoneal injection at 24 and 48 hours post-MCAO. Infarction volume, mortality and neurological function were assessed at 72 hours after ischemic insult. Immunofluorescence and Western blotting were performed to determine the expression of autophagy-related proteins P62, LC3 and Beclin-1 in the penumbra area. No significant changes in mortality and physiological variables (heart rate, blood glucose levels and arterial blood gases) were observed between the different groups. However, MCAO resulted in enhanced conversion of LC3-I into LC3-II, P62 degradation, high levels of Beclin-1, a large area infarction (26.3±3.6%) and serious neurobehavioral deficits. GM1 (50 mg/kg) treatment significantly reduced the autophagy activation, neurobehavioral dysfunctions, and infarction volume (from 26.3% to 19.5%) without causing significant adverse side effects. However, this biological function could be abolished by Tat–Beclin-1. In conclusion: GM1 demonstrated safe and robust neuroprotective effects that are associated with the inhibition of autophagy following experimental stroke. PMID:26751695

  20. GM1 Ganglioside in Parkinson’s Disease: Pilot Study of Effects on Dopamine Transporter Binding

    PubMed Central

    Schneider, Jay S.; Cambi, Franca; Gollomp, Stephen M.; Kuwabara, Hiroto; Brašić, James R.; Leiby, Benjamin; Sendek, Stephanie; Wong, Dean F.

    2015-01-01

    Objective GM1 ganglioside has been suggested as a treatment for Parkinson’s disease (PD), potentially having symptomatic and disease modifying effects. The current pilot imaging study was performed to examine effects of GM1 on dopamine transporter binding, as a surrogate measure of disease progression, studied longitudinally. Methods Positron emission tomography (PET) imaging data were obtained from a subset of subjects enrolled in a delayed start clinical trial of GM1 in PD1: 15 Early-start (ES) subjects, 14 Delayed-start (DS) subjects, and 11 Comparison (standard-of-care) subjects. Treatment subjects were studied over a 2.5 year period while Comparison subjects were studied over 2 years. Dynamic PET scans were performed over 90 minutes following injection of [11C]methylphenidate. Regional values of binding potential (BPND) were analyzed for several striatal volumes of interest. Results Clinical results for this subset of subjects were similar to those previously reported for the larger study group. ES subjects showed early symptomatic improvement and slow symptom progression over the study period. DS and Comparison subjects were initially on the same symptom progression trajectory but diverged once DS subjects received GM1 treatment. Imaging results showed significant slowing of BPND loss in several striatal regions in GM1-treated subjects and in some cases, an increased BPND in some striatal regions was detected after GM1 use. Interpretation Results of this pilot imaging study provide additional data to suggest a potential disease modifying effect of GM1 on PD. These results need to be confirmed in a larger number of subjects. PMID:26099170

  1. Antidepressant-Like Effects of GM1 Ganglioside Involving the BDNF Signaling Cascade in Mice

    PubMed Central

    Song, Lu; Wang, Cheng-Niu; Zhang, Wei; Huang, Chao; Tong, Li-Juan

    2016-01-01

    Background: Depression is a serious psychiatric disorder that easily causes physical impairments and a high suicide rate. Monosialotetrahexosylganglioside is a crucial ganglioside for the central nervous system and has been reported to affect the function of the brain derived neurotrophic factor system. This study is aimed to evaluate whether monosialotetrahexosylganglioside has antidepressant-like effects. Methods: Antidepressant-like effects of monosialotetrahexosylganglioside were assessed in the chronic social defeat stress model of depression, and various behavioral tests were performed. Changes in the brain derived neurotrophic factor signaling pathway after chronic social defeat stress and monosialotetrahexosylganglioside treatment were also investigated. A tryptophan hydroxylase inhibitor and brain derived neurotrophic factor signaling inhibitors were used to determine the antidepressant mechanisms of monosialotetrahexosylganglioside. Results: Monosialotetrahexosylganglioside administration significantly reversed the chronic social defeat stress-induced reduction of sucrose preference and social interaction in mice and also prevented the increased immobility time in the forced swim test and tail suspension test. In addition, monosialotetrahexosylganglioside completely ameliorated the stress-induced dysfunction of brain derived neurotrophic factor signaling cascade in the hippocampus and medial prefrontal cortex, 2 regions closely involved in the pathophysiology of depression. Furthermore, the usage of brain derived neurotrophic factor signaling cascade inhibitors, K252a and anti-brain derived neurotrophic factor antibody, each abolished the antidepressant-like effects of monosialotetrahexosylganglioside, while the usage of a serotonin system inhibitor did not. Conclusions: Taken together, our findings suggest that monosialotetrahexosylganglioside indeed has antidepressant-like effects, and these effects were mediated through the activation of brain derived

  2. Static and dynamic magnetic properties and interplay of Dy3+, Gd3+ and Mn3+ spins in orthorhombic DyMnO3 and GdMnO3 nanoparticles

    NASA Astrophysics Data System (ADS)

    Das, Raja; Jaiswal, Adhish; Poddar, Pankaj

    2013-01-01

    Single-phase orthorhombic DyMnO3 and GdMnO3 nanoparticles in the size range 60-70 and 35-45 nm, respectively, were synthesized using a modified hydrothermal method. The magnetic property measurements of DyMnO3 nanocrystals show anomalies around ˜43 K (antiferromagnetic (AFM) coupling between Mn3+ spins) and at 7 K in the form of a peak in the zero-field-cooled curve (AFM coupling between Dy3+ spins). Whereas, GdMnO3 undergoes a phase transition at ˜42 K from paramagnetic to an incommensurate-antiferromagnetic phase (ICAFM) followed by a second anomaly at ˜22 K, which could be associated with the transition from ICAFM into a canted A-type AFM ordering of the Mn3+ spins. This transition is followed by a long-range ordering of the Gd3+ moments at 6 K yielding the canting of the Gd3+ spins with a ferromagnetic (FM) component antiparallel to the FM moment of the canted Mn3+ spins. No anomaly near the Néel temperature of the Mn moments for both DyMnO3 and GdMnO3 nanoparticles was observed in ac magnetization which were observed in dc magnetization. The room temperature Raman spectra of DyMnO3 shows two most intense Raman modes at 480 and 609 cm-1 which can be assigned to an antisymmetric Jahn-Teller stretching mode and a symmetric or breathing stretching mode, respectively, involving Mn-O bond stretching.

  3. Comparative study of the Mn4+2E → 4A2 luminescence in isostructural RE2Sn2O7:Mn4+ pyrochlores (RE3+ = Y3+, Lu3+ or Gd3+)

    NASA Astrophysics Data System (ADS)

    Senden, Tim; Broers, Fréderique T. H.; Meijerink, Andries

    2016-10-01

    Red emitting Mn4+-doped crystalline materials have potential for application in light emitting devices and therefore it is important to understand how the optical properties of Mn4+ are influenced by the host lattice the Mn4+ ions are situated in. In this work we investigate the effect of the host cations in the second coordination sphere on the Mn4+ emission by studying the luminescence of Mn4+ ions doped into three isostructural rare earth (RE) stannate RE2Sn2O7 pyrochlores (RE3+ = Y3+, Lu3+ or Gd3+). It is found that the energies of the Mn4+4T1 and 4T2 states significantly increase with decreasing Mn4+-O2- distance, whereas the energy of the 2E level shows a small shift to higher energies from RE3+ = Gd3+ to Lu3+ to Y3+. The observed trend for the 2E level energy is not related to the size of the RE3+ ion and is not in line with theoretical calculations reported previously. Low temperature emission spectra of the RE2Sn2O7:Mn4+ phosphors reveal that only asymmetrical vibronic modes couple to the 2E → 4A2 transition and furthermore show there is significant and unexpected local disorder for Mn4+ in Gd2Sn2O7 that is not observed for Mn4+ in the other hosts. Photoluminescence decay measurements demonstrate that the luminescence of RE2Sn2O7:Mn4+ is strongly quenched below room temperature which is assigned to non-radiative relaxation via a low-lying O2- → Mn4+ charge-transfer state.

  4. Ganglioside GM3 synthase depletion reverses neuropathic pain and small fiber neuropathy in diet-induced diabetic mice

    PubMed Central

    Jayaraj, Nirupa D; Wilson, Heather M; Ren, Dongjun; Flood, Kelsey; Wang, Xiao-Qi; Shum, Andrew; Miller, Richard J; Paller, Amy S

    2016-01-01

    Background Small fiber neuropathy is a well-recognized complication of type 2 diabetes and has been shown to be responsible for both neuropathic pain and impaired wound healing. In previous studies, we have demonstrated that ganglioside GM3 depletion by knockdown of GM3 synthase fully reverses impaired wound healing in diabetic mice. However, the role of GM3 in neuropathic pain and small fiber neuropathy in diabetes is unknown. Purpose Determine whether GM3 depletion is able to reverse neuropathic pain and small fibers neuropathy and the mechanism of the reversal. Results We demonstrate that GM3 synthase knockout and the resultant GM3 depletion rescues the denervation in mouse footpad skin and fully reverses the neuropathic pain in diet-induced obese diabetic mice. In cultured dorsal root ganglia from diet-induced diabetic mice, GM3 depletion protects against increased intracellular calcium influx in vitro. Conclusions These studies establish ganglioside GM3 as a new candidate responsible for neuropathic pain and small fiber neuropathy in diabetes. Moreover, these observations indicate that systemic or topically applied interventions aimed at depleting GM3 may improve both the painful neuropathy and the wound healing impairment in diabetes by protecting against nerve end terminal degeneration, providing a disease-modifying approach to this common, currently intractable medical issue. PMID:27590073

  5. Liquid chromatography/electrospray ionisation-tandem mass spectrometry quantification of GM2 gangliosides in human peripheral cells and plasma.

    PubMed

    Fuller, Maria; Duplock, Stephen; Hein, Leanne K; Rigat, Brigitte A; Mahuran, Don J

    2014-08-01

    GM2 gangliosidosis is a group of inherited neurodegenerative disorders resulting primarily from the excessive accumulation of GM2 gangliosides (GM2) in neuronal cells. As biomarkers for categorising patients and monitoring the effectiveness of developing therapies are lacking for this group of disorders, we sought to develop methodology to quantify GM2 levels in more readily attainable patient samples such as plasma, leukocytes, and cultured skin fibroblasts. Following organic extraction, gangliosides were partitioned into the aqueous phase and isolated using C18 solid-phase extraction columns. Relative quantification of three species of GM2 was achieved using LC/ESI-MS/MS with d35GM1 18:1/18:0 as an internal standard. The assay was linear over the biological range, and all GM2 gangliosidosis patients were demarcated from controls by elevated GM2 in cultured skin fibroblast extracts. However, in leukocytes only some molecular species could be used for differentiation and in plasma only one was informative. A reduction in GM2 was easily detected in patient skin fibroblasts after a short treatment with media from normal cells enriched in secreted β-hexosaminidase. This method may show promise for measuring the effectiveness of experimental therapies for GM2 gangliosidosis by allowing quantification of a reduction in the primary storage burden. PMID:24769373

  6. Gangliosides as a potential new class of stem cell markers: the case of GD1a in human bone marrow mesenchymal stem cells.

    PubMed

    Bergante, Sonia; Torretta, Enrica; Creo, Pasquale; Sessarego, Nadia; Papini, Nadia; Piccoli, Marco; Fania, Chiara; Cirillo, Federica; Conforti, Erika; Ghiroldi, Andrea; Tringali, Cristina; Venerando, Bruno; Ibatici, Adalberto; Gelfi, Cecilia; Tettamanti, Guido; Anastasia, Luigi

    2014-03-01

    Owing to their exposure on the cell surface and the possibility of being directly recognized with specific antibodies, glycosphingolipids have aroused great interest in the field of stem cell biology. In the search for specific markers of the differentiation of human bone marrow mesenchymal stem cells (hBMSCs) toward osteoblasts, we studied their glycosphingolipid pattern, with particular attention to gangliosides. After lipid extraction and fractionation, gangliosides, metabolically (3)H-labeled in the sphingosine moiety, were separated by high-performance TLC and chemically characterized by MALDI MS. Upon induction of osteogenic differentiation, a 3-fold increase of ganglioside GD1a was observed. Therefore, the hypothesis of GD1a involvement in hBMSCs commitment toward the osteogenic phenotype was tested by comparison of the osteogenic propensity of GD1a-highly expressing versus GD1a-low expressing hBMSCs and direct addition of GD1a in the differentiation medium. It was found that either the high expression of GD1a in hBMSCs or the addition of GD1a in the differentiation medium favored osteogenesis, providing a remarkable increase of alkaline phosphatase. It was also observed that ganglioside GD2, although detectable in hBMSCs by immunohistochemistry with an anti-GD2 antibody, could not be recognized by chemical analysis, likely reflecting a case, not uncommon, of molecular mimicry.

  7. The biosynthesis of gangliosides. The incorporation of galactose, N-acetylgalactosamine and N-acetylneuraminic acid into endogenous acceptors of subcellular particles from rat brain in vitro

    PubMed Central

    Arce, A.; Maccioni, H. J.; Caputto, R.

    1971-01-01

    Gangliosides bound to subcellular particles from rat brain were labelled by incubation of the particles (i) with CMP-N[3H]-acetylneuraminic acid and (ii) simultaneously, with CMP-N[3H]-acetylneuraminic acid and UDP-N-acetyl-[14C1]galactosamine or with CMP-N[3H]-acetylneuraminic acid and UDP-[U-14C]-galactose. Analysis of the labelled gangliosides showed that in (i), (a) the labelling was mostly in the neuraminidase-labile sialyl groups, (b) rigid relationships exist between the enzymes and the sialyl acceptors; the enzymes are not free to interact with all the specific substrates present in the preparation and (c) the precursor of the trisialoganglioside was the major disialoganglioside with a sialyl 2→8 sialyl group. In (ii), (a) precursor–product relationships between the main pools of each ganglioside apparently do not exist, (b) for the labelling of Tay–Sachs ganglioside the amount formed from hematoside was at least 2.5 times that from aminoglycolipid and (c) the major monosialoganglioside was the precursor for the major disialoganglioside with a sialyl 2→8 sialyl group. PMID:5119784

  8. Gangliosides as a potential new class of stem cell markers: the case of GD1a in human bone marrow mesenchymal stem cells[S

    PubMed Central

    Bergante, Sonia; Torretta, Enrica; Creo, Pasquale; Sessarego, Nadia; Papini, Nadia; Piccoli, Marco; Fania, Chiara; Cirillo, Federica; Conforti, Erika; Ghiroldi, Andrea; Tringali, Cristina; Venerando, Bruno; Ibatici, Adalberto; Gelfi, Cecilia; Tettamanti, Guido; Anastasia, Luigi

    2014-01-01

    Owing to their exposure on the cell surface and the possibility of being directly recognized with specific antibodies, glycosphingolipids have aroused great interest in the field of stem cell biology. In the search for specific markers of the differentiation of human bone marrow mesenchymal stem cells (hBMSCs) toward osteoblasts, we studied their glycosphingolipid pattern, with particular attention to gangliosides. After lipid extraction and fractionation, gangliosides, metabolically 3H-labeled in the sphingosine moiety, were separated by high-performance TLC and chemically characterized by MALDI MS. Upon induction of osteogenic differentiation, a 3-fold increase of ganglioside GD1a was observed. Therefore, the hypothesis of GD1a involvement in hBMSCs commitment toward the osteogenic phenotype was tested by comparison of the osteogenic propensity of GD1a-highly expressing versus GD1a-low expressing hBMSCs and direct addition of GD1a in the differentiation medium. It was found that either the high expression of GD1a in hBMSCs or the addition of GD1a in the differentiation medium favored osteogenesis, providing a remarkable increase of alkaline phosphatase. It was also observed that ganglioside GD2, although detectable in hBMSCs by immunohistochemistry with an anti-GD2 antibody, could not be recognized by chemical analysis, likely reflecting a case, not uncommon, of molecular mimicry. PMID:24449473

  9. Erythrocyte gangliosides act as receptors for Neisseria subflava: identification of the Sia-1 adhesin.

    PubMed Central

    Nyberg, G; Strömberg, N; Jonsson, A; Karlsson, K A; Normark, S

    1990-01-01

    Neisseria gonorrhoeae was recently shown to bind to a subset of lactose-containing glycolipids (N. Strömberg, C. Deal, G. Nyberg, S. Normark, M. So, and K.-A. Karlsson, Proc. Natl. Acad. Sci. USA 85:4902-4906, 1988). A number of commensal Neisseria strains were also shown to be lactose binders. In addition, Neisseria subflava bound to immobilized gangliosides, such as hematoside and sialosyl paragloboside, carrying the NeuAc alpha 2-3Gal beta 1-4Glc sequence. To a lesser extent, N. gonorrhoeae also bound to this receptor in vitro. In N. subflava GN01, this binding property mediated agglutination of human erythrocytes in a neuraminidase-sensitive fashion. Nitrosoguanidine-induced nonhemagglutinative mutants of N. subflava GN01 had lost the ability to bind hematoside and sialosylparagloboside but remained able to bind lactosylceramide and gangliotetraosylceramide. These mutants fell into three classes with respect to their outer membrane protein profiles in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Class 1 mutants were identical to the parent strain save for the loss of a 27-kilodalton (kDa) protein. Class 2 mutants showed an outer membrane protein profile identical to that of the wild type, whereas mutants belonging to class 3 showed a number of changes, including the apparent absence of the 27-kDa protein. The 27-kDa protein from N. subflava GN01 was purified from the supernatant. A polyclonal antiserum to the purified Sia-1 protein as well as a Sia-1-specific monoclonal antibody inhibited hemagglutination by strain GN01. The purified Sia-1 protein in the presence of diluted anti-Sia-1 antiserum mediated a neuraminidase-sensitive hemagglutination. The purified Sia protein from a class 2 mutant was not able to hemagglutinate when cross-linked with antibodies, suggesting that it is a mutant form of Sia-1 affected in the receptor-binding site. Immunoelectron microscopy with a Sia-1-specific monoclonal antibody revealed that the adhesin was

  10. Electrophysiological characteristics of primary afferent fibers after systemic administration of anti-GD2 ganglioside antibody.

    PubMed

    Xiao, W H; Yu, A L; Sorkin, L S

    1997-01-01

    An animal model showing mechanical allodynia following systemic bolus injection of a human/mouse chimeric monoclonal antibody to the GD2 ganglioside (ch14.18) has been established (e.g. pain behavior generated by a light tactile stimulus). This is of clinical relevance since ch14.18 is a promising experimental treatment for pediatric neuroblastoma. The present study examined the hypothesis that allodynic effects of the anti-GD2 antibody are mediated by actions on cutaneous nerve fibers. After determining the basal magnitude of the mechanical stimulus required to produce withdrawal, ch14.18, a murine form of the anti-GD2 antibody of IgG2a isotype (14G2a), a control murine anti-melanoma antibody of IgG2a isotype (9.2.27) or saline was injected through a previously implanted jugular cannula. The experimenter was blinded to the syringe contents. Withdrawal threshold was tested at 15 min intervals for 1 h. After administration of either ch14.18 or 14G2a mechanical allodynia typically started within the first 15 min and persisted throughout the hour of behavioral testing. In the control antibody group, a modest change in tactile withdrawal threshold was observed at the 60 min time point only. Rats were then anesthetized with pentobarbital and prepared for single fiber recordings from the sural nerve. Fibers were classified based on conduction velocity, as A beta (> 25 m/s), A delta (2-25 m/s) or C (< 2 m/s). Background activity (BA) was observed in a significant number of A delta (12/61) and C (32/42) fibers in both anti-GD2 treated groups compared to the anti-melanoma antibody (1/17 A delta and 2/10 C fibers) and saline (0/26 A delta and 0/19 C fibers) treated groups. Mean mechanical threshold for A delta fibers in all three antibody treated groups was significantly reduced compared to the saline control; this was not observed for C-fibers in any group. Intravenous bolus injection (15 mg/kg) and infusion of lidocaine (plasma level 0.3-2.2 micrograms/ml) both reduced

  11. Structural and mutational analyses of the receptor binding domain of botulinum D/C mosaic neurotoxin: Insight into the ganglioside binding mechanism

    SciTech Connect

    Nuemket, Nipawan; Tanaka, Yoshikazu; Tsukamoto, Kentaro; Tsuji, Takao; Nakamura, Keiji; Kozaki, Shunji; Yao, Min; Tanaka, Isao

    2011-07-29

    Highlights: {yields} We determined the crystal structure of the receptor binding domain of BoNT in complex with 3'-sialyllactose. {yields} An electron density derived from the 3'-sialyllactose was confirmed at the cleft in the C-terminal subdomain. {yields} Alanine site-directed mutagenesis showed that GBS and GBL are important for ganglioside binding. {yields} A cell binding mechanism, which involves cooperative contribution of two sites, was proposed. -- Abstract: Clostridium botulinum type D strain OFD05, which produces the D/C mosaic neurotoxin, was isolated from cattle killed by the recent botulism outbreak in Japan. The D/C mosaic neurotoxin is the most toxic of the botulinum neurotoxins (BoNT) characterized to date. Here, we determined the crystal structure of the receptor binding domain of BoNT from strain OFD05 in complex with 3'-sialyllactose at a resolution of 3.0 A. In the structure, an electron density derived from the 3'-sialyllactose was confirmed at the cleft in the C-terminal subdomain. Alanine site-directed mutagenesis showed the significant contribution of the residues surrounding the cleft to ganglioside recognition. In addition, a loop adjoining the cleft also plays an important role in ganglioside recognition. In contrast, little effect was observed when the residues located around the surface previously identified as the protein receptor binding site in other BoNTs were substituted. The results of cell binding analysis of the mutants were significantly correlated with the ganglioside binding properties. Based on these observations, a cell binding mechanism of BoNT from strain OFD05 is proposed, which involves cooperative contribution of two ganglioside binding sites.

  12. Doxorubicin-conjugated β-NaYF4:Gd(3+)/Tb(3+) multifunctional, phosphor nanorods: a multi-modal, luminescent, magnetic probe for simultaneous optical and magnetic resonance imaging and an excellent pH-triggered anti-cancer drug delivery nanovehicle.

    PubMed

    Padhye, Preeti; Alam, Aftab; Ghorai, Suvankar; Chattopadhyay, Samit; Poddar, Pankaj

    2015-12-14

    Herein, we report the fabrication of a multifunctional nanoprobe based on highly monodispersed, optically and magnetically active, biocompatible, PEI-functionalized, highly crystalline β-NaYF4:Gd(3+)/Tb(3+) nanorods as an excellent multi-modal optical/magnetic imaging tool and a pH-triggered intracellular drug delivery nanovehicle. The static and dynamic photoluminescence spectroscopy showed the presence of sharp emission peaks, with long lifetimes (∼3.5 milliseconds), suitable for optical imaging. The static magnetic susceptibility measurements at room temperature showed a strong paramagnetic signal (χ∼ 3.8 × 10(-5) emu g(-1) Oe(-1)). The nuclear magnetic resonance (NMR) measurements showed fair T1 relaxivity (r1 = 1.14 s(-1) mM(-1)) and magnetic resonance imaging gave enhanced T1-weighted MRI images with increased concentrations of β-NaYF4:Gd(3+)/Tb(3+) making them suitable for simultaneous magnetic resonance imaging. In addition, an anticancer drug, doxorubicin (DOX) was conjugated to the amine-functionalized β-NaYF4:Gd(3+)/Tb(3+) nanorods via pH-sensitive hydrazone bond linkages enabling them as a pH-triggered, site-specific drug delivery nanovehicle for DOX release inside tumor cells. A comparison between in vitro DOX release studies undertaken in normal physiological (pH 7.4) and acidic (pH 5.0) environments showed an enhanced DOX dissociation (∼80%) at pH 5.0. The multifunctional material was also applied as an optical probe to confirm the conjugation of DOX and to monitor DOX release via a fluorescence resonance energy transfer (FRET) mechanism. The DOX-conjugated β-NaYF4:Gd(3+)/Tb(3+) nanorods exhibited a cytotoxic effect on MCF-7 breast cancer cells and their uptake by MCF-7 cells was demonstrated using confocal laser scanning microscopy and flow cytometry. The comparative cellular uptakes of free DOX and DOX-conjugated β-NaYF4:Gd(3+)/Tb(3+) nanorods were studied in tumor microenvironment conditions (pH 6.5) using confocal imaging, which

  13. Exogenous and Endogeneous Disialosyl Ganglioside GD1b Induces Apoptosis of MCF-7 Human Breast Cancer Cells

    PubMed Central

    Ha, Sun-Hyung; Lee, Ji-Min; Kwon, Kyung-Min; Kwak, Choong-Hwan; Abekura, Fukushi; Park, Jun-Young; Cho, Seung-Hak; Lee, Kichoon; Chang, Young-Chae; Lee, Young-Choon; Choi, Hee-Jung; Chung, Tae-Wook; Ha, Ki-Tae; Chang, Hyeun-Wook; Kim, Cheorl-Ho

    2016-01-01

    Gangliosides have been known to play a role in the regulation of apoptosis in cancer cells. This study has employed disialyl-ganglioside GD1b to apoptosis in human breast cancer MCF-7 cells using exogenous treatment of the cells with GD1b and endogenous expression of GD1b in MCF-7 cells. First, apoptosis in MCF-7 cells was observed after treatment of GD1b. Treatment of MCF-7 cells with GD1b reduced cell growth rates in a dose and time dependent manner during GD1b treatment, as determined by XTT assay. Among the various gangliosides, GD1b specifically induced apoptosis of the MCF-7 cells. Flow cytometry and immunofluorescence assays showed that GD1b specifically induces apoptosis in the MCF-7 cells with Annexin V binding for apoptotic actions in early stage and propidium iodide (PI) staining the nucleus of the MCF-7 cells. Treatment of MCF-7 cells with GD1b activated apoptotic molecules such as processed forms of caspase-8, -7 and PARP (Poly(ADP-ribose) polymerase), without any change in the expression of mitochondria-mediated apoptosis molecules such as Bax and Bcl-2. Second, to investigate the effect of endogenously produced GD1b on the regulation of cell function, UDP-gal: β1,3-galactosyltransferase-2 (GD1b synthase, Gal-T2) gene has been transfected into the MCF-7 cells. Using the GD1b synthase-transfectants, apoptosis-related signal proteins linked to phenotype changes were examined. Similar to the exogenous GD1b treatment, the cell growth of the GD1b synthase gene-transfectants was significantly suppressed compared with the vector-transfectant cell lines and transfection activated the apoptotic molecules such as processed forms of caspase-8, -7 and PARP, but not the levels of expression of Bax and Bcl-2. GD1b-induced apoptosis was blocked by caspase inhibitor, Z-VAD. Therefore, taken together, it was concluded that GD1b could play an important role in the regulation of breast cancer apoptosis. PMID:27144558

  14. Porcine Sapelovirus Uses α2,3-Linked Sialic Acid on GD1a Ganglioside as a Receptor

    PubMed Central

    Kim, Deok-Song; Son, Kyu-Yeol; Koo, Kyung-Min; Kim, Ji-Yun; Alfajaro, Mia Madel; Park, Jun-Gyu; Hosmillo, Myra; Soliman, Mahmoud; Baek, Yeong-Bin; Cho, Eun-Hyo; Lee, Ju-Hwan; Kang, Mun-Il

    2016-01-01

    ABSTRACT The receptor(s) for porcine sapelovirus (PSV), which causes diarrhea, pneumonia, polioencephalomyelitis, and reproductive disorders in pigs, remains largely unknown. Given the precedent for other picornaviruses which use terminal sialic acids (SAs) as receptors, we examined the role of SAs in PSV binding and infection. Using a variety of approaches, including treating cells with a carbohydrate-destroying chemical (NaIO4), mono- or oligosaccharides (N-acetylneuraminic acid, galactose, and 6′-sialyllactose), linkage-specific sialidases (neuraminidase and sialidase S), lectins (Maakia amurensis lectin and Sambucus nigra lectin), proteases (trypsin and chymotrypsin), and glucosylceramide synthase inhibitors (dl-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol and phospholipase C), we demonstrated that PSV could recognize α2,3-linked SA on glycolipids as a receptor. On the other hand, PSVs had no binding affinity for synthetic histo-blood group antigens (HBGAs), suggesting that PSVs could not use HBGAs as receptors. Depletion of cell surface glycolipids followed by reconstitution studies indicated that GD1a ganglioside, but not other gangliosides, could restore PSV binding and infection, further confirming α2,3-linked SA on GD1a as a PSV receptor. Our results could provide significant information on the understanding of the life cycle of sapelovirus and other picornaviruses. For the broader community in the area of pathogens and pathogenesis, these findings and insights could contribute to the development of affordable, useful, and efficient drugs for anti-sapelovirus therapy. IMPORTANCE The porcine sapelovirus (PSV) is known to cause enteritis, pneumonia, polioencephalomyelitis, and reproductive disorders in pigs. However, the receptor(s) that the PSV utilizes to enter host cells remains largely unknown. Using a variety of approaches, we showed that α2,3-linked terminal sialic acid (SA) on the cell surface GD1a ganglioside could be used for PSV

  15. Diode-pumped Nd:Gd3Ga5O12-KTiOPO4 green laser doubly passively Q-switched mode-locked by GaAs and Cr4+:YAG saturable absorbers

    NASA Astrophysics Data System (ADS)

    Qiao, Junpeng; Zhao, Jia; Yang, Kejian; Zhao, Shengzhi; Li, Yufei; Li, Guiqiu; Li, Dechun; Qiao, Wenchao; Li, Tao; Chu, Hongwei

    2015-03-01

    By simultaneously employing GaAs and Cr4+:YAG saturable absorbers, a diode-pumped doubly passively Q-switched and mode-locked (DP-QML) Nd:Gd3Ga5O12 (Nd:GGG)/KTiOPO4 (KTP) green laser has been presented. At the maximum incident pump power of 7.69 W, the obtained average output power, the pulse duration of the Q-switched envelope, the mode-locked pulse width and the pulse repetition rate are 62 mW, 16.8 ns, 352 ps, and 15.5 kHz, respectively, corresponding to a pulse energy of 4.2 µJ and a peak power of 0.25 kW. In comparison with singly passively Q-switched and mode-locked (SP-QML) green laser with GaAs or Cr4+:YAG saturable absorbers, the DP-QML green laser can generate shorter pulse width, deeper modulation depth and higher peak power. The coupled equations for diode-pumped doubly passively QML Nd:GGG/KTP green laser are given and the numerical simulations are in good agreement with the experimental results.

  16. Molecular recognition and colorimetric detection of cholera toxin by poly(diacetylene) liposomes incorporating G{sub m1} ganglioside

    SciTech Connect

    Pan, J.J.; Charych, D.

    1997-03-19

    Molecular recognition sites on cell membranes serve as the main communication channels between the inside of a cell and its surroundings. Upon receptor binding, cellular messages such as ion channel opening or activation of enzymes are triggered. In this report, we demonstrate that artificial cell membranes made from conjugated lipid polymers (poly(diacetylene)) can, on a simple level, mimic membrane processes of molecular recognition and signal transduction. The ganglioside GM1 was incorporated into poly(diacetylene) liposomes. Molecular recognition of cholera toxin at the interface of the liposome resulted in a change of the membrane color due to conformational charges in the conjugated (ene-yne) polymer backbone. The `colored liposomes` might be used as simple colorimetric sensors for drug screening or as new tools to study membrane-membrane or membrane-receptor interactions. 21 refs., 3 figs.

  17. Effects of ganglioside G(M1) and erythropoietin on spinal cord lesions in rats: functional and histological evaluations

    PubMed Central

    Marcon, Raphael Martus; Cristante, Alexandre Fogaça; de Barros Filho, Tarcísio Eloy Pessoa; Ferreira, Ricardo; dos Santos, Gustavo Bispo

    2016-01-01

    OBJECTIVE: To evaluate the functional and histological effects of ganglioside G(M1) and erythropoietin after experimental spinal cord contusion injury. METHODS: Fifty male Wistar rats underwent experimental spinal cord lesioning using an NYU-Impactor device and were randomly divided into the following groups, which received treatment intraperitoneally. The G(M1) group received ganglioside G(M1) (30 mg/kg); the erythropoietin group received erythropoietin (1000 IU/kg); the combined group received both drugs; and the saline group received saline (0.9%) as a control. A fifth group was the laminectomy group, in which the animals were subjected to laminectomy alone, without spinal lesioning or treatment. The animals were evaluated according to the Basso, Beattie and Bresnahan (BBB) scale, motor evoked potential recordings and, after euthanasia, histological analysis of spinal cord tissue. RESULTS: The erythropoietin group had higher BBB scores than the G(M1) group. The combined group had the highest BBB scores, and the saline group had the lowest BBB scores. No significant difference in latency was observed between the three groups that underwent spinal cord lesioning and intervention. However, the combined group showed a significantly higher signal amplitude than the other treatment groups or the saline group (p<0.01). Histological tissue analysis showed no significant difference between the groups. Axonal index was significantly enhanced in the combined group than any other intervention (p<0.01). CONCLUSION: G(M1) and erythropoietin exert therapeutic effects on axonal regeneration and electrophysiological and motor functions in rats subjected to experimental spinal cord lesioning and administering these two substances in combination potentiates their effects. PMID:27438570

  18. Sphingolipids: Key Regulators of Apoptosis and Pivotal Players in Cancer Drug Resistance

    PubMed Central

    Giussani, Paola; Tringali, Cristina; Riboni, Laura; Viani, Paola; Venerando, Bruno

    2014-01-01

    Drug resistance elicited by cancer cells still constitutes a huge problem that frequently impairs the efficacy of both conventional and novel molecular therapies. Chemotherapy usually acts to induce apoptosis in cancer cells; therefore, the investigation of apoptosis control and of the mechanisms used by cancer cells to evade apoptosis could be translated in an improvement of therapies. Among many tools acquired by cancer cells to this end, the de-regulated synthesis and metabolism of sphingolipids have been well documented. Sphingolipids are known to play many structural and signalling roles in cells, as they are involved in the control of growth, survival, adhesion, and motility. In particular, in order to increase survival, cancer cells: (a) counteract the accumulation of ceramide that is endowed with pro-apoptotic potential and is induced by many drugs; (b) increase the synthesis of sphingosine-1-phosphate and glucosylceramide that are pro-survivals signals; (c) modify the synthesis and the metabolism of complex glycosphingolipids, particularly increasing the levels of modified species of gangliosides such as 9-O acetylated GD3 (αNeu5Ac(2-8)αNeu5Ac(2-3)βGal(1-4)βGlc(1-1)Cer) or N-glycolyl GM3 (αNeu5Ac (2-3)βGal(1-4)βGlc(1-1)Cer) and de-N-acetyl GM3 (NeuNH(2)βGal(1-4)βGlc(1-1)Cer) endowed with anti-apoptotic roles and of globoside Gb3 related to a higher expression of the multidrug resistance gene MDR1. In light of this evidence, the employment of chemical or genetic approaches specifically targeting sphingolipid dysregulations appears a promising tool for the improvement of current chemotherapy efficacy. PMID:24625663

  19. Doxorubicin-conjugated β-NaYF4:Gd3+/Tb3+ multifunctional, phosphor nanorods: a multi-modal, luminescent, magnetic probe for simultaneous optical and magnetic resonance imaging and an excellent pH-triggered anti-cancer drug delivery nanovehicle

    NASA Astrophysics Data System (ADS)

    Padhye, Preeti; Alam, Aftab; Ghorai, Suvankar; Chattopadhyay, Samit; Poddar, Pankaj

    2015-11-01

    Herein, we report the fabrication of a multifunctional nanoprobe based on highly monodispersed, optically and magnetically active, biocompatible, PEI-functionalized, highly crystalline β-NaYF4:Gd3+/Tb3+ nanorods as an excellent multi-modal optical/magnetic imaging tool and a pH-triggered intracellular drug delivery nanovehicle. The static and dynamic photoluminescence spectroscopy showed the presence of sharp emission peaks, with long lifetimes (~3.5 milliseconds), suitable for optical imaging. The static magnetic susceptibility measurements at room temperature showed a strong paramagnetic signal (χ ~ 3.8 × 10-5 emu g-1 Oe-1). The nuclear magnetic resonance (NMR) measurements showed fair T1 relaxivity (r1 = 1.14 s-1 mM-1) and magnetic resonance imaging gave enhanced T1-weighted MRI images with increased concentrations of β-NaYF4:Gd3+/Tb3+ making them suitable for simultaneous magnetic resonance imaging. In addition, an anticancer drug, doxorubicin (DOX) was conjugated to the amine-functionalized β-NaYF4:Gd3+/Tb3+ nanorods via pH-sensitive hydrazone bond linkages enabling them as a pH-triggered, site-specific drug delivery nanovehicle for DOX release inside tumor cells. A comparison between in vitro DOX release studies undertaken in normal physiological (pH 7.4) and acidic (pH 5.0) environments showed an enhanced DOX dissociation (~80%) at pH 5.0. The multifunctional material was also applied as an optical probe to confirm the conjugation of DOX and to monitor DOX release via a fluorescence resonance energy transfer (FRET) mechanism. The DOX-conjugated β-NaYF4:Gd3+/Tb3+ nanorods exhibited a cytotoxic effect on MCF-7 breast cancer cells and their uptake by MCF-7 cells was demonstrated using confocal laser scanning microscopy and flow cytometry. The comparative cellular uptakes of free DOX and DOX-conjugated β-NaYF4:Gd3+/Tb3+ nanorods were studied in tumor microenvironment conditions (pH 6.5) using confocal imaging, which showed an increased uptake of DOX

  20. Nitrogen dioxide induced changes in level of free fatty acids, triglyceride, esterified fatty acid, ganglioside and lipase activity in the guinea pig brain

    SciTech Connect

    Farahani, H.; Hasan, M. )

    1992-02-01

    The biochemical response to controlled inhalation of nitrogen dioxide (NO2) was studied in 18 male guinea pigs. Animals were exposed to 2.5, 5.0, and 10 ppm NO2 for 2h daily for 35 consecutive days, and the results compared with six control animals exposed to filtered air for 2h daily for same period. Five biochemical parameters, including triglyceride, free fatty acids, esterified fatty acid, ganglioside and lipase activity were measured immediately after the last day of exposure. At 2.5 ppm NO2 inhalation no significant changes occurred in any region of the central nervous system (CNS). While as the dose concentration was increased to 5 and 10 ppm nitrogen dioxide, significant dose-related alteration were observed in the levels of triglyceride, free fatty acid, esterified fatty acid, ganglioside and lipase activity in the different regions of the guinea pig CNS.

  1. Increased Expression of Simple Ganglioside Species GM2 and GM3 Detected by MALDI Imaging Mass Spectrometry in a Combined Rat Model of Aβ Toxicity and Stroke

    PubMed Central

    Caughlin, Sarah; Hepburn, Jeffrey D.; Park, Dae Hee; Jurcic, Kristina; Yeung, Ken K.-C.; Cechetto, David F.; Whitehead, Shawn N.

    2015-01-01

    The aging brain is often characterized by the presence of multiple comorbidities resulting in synergistic damaging effects in the brain as demonstrated through the interaction of Alzheimer’s disease (AD) and stroke. Gangliosides, a family of membrane lipids enriched in the central nervous system, may have a mechanistic role in mediating the brain’s response to injury as their expression is altered in a number of disease and injury states. Matrix-Assisted Laser Desorption Ionization (MALDI) Imaging Mass Spectrometry (IMS) was used to study the expression of A-series ganglioside species GD1a, GM1, GM2, and GM3 to determine alteration of their expression profiles in the presence of beta-amyloid (Aβ) toxicity in addition to ischemic injury. To model a stroke, rats received a unilateral striatal injection of endothelin-1 (ET-1) (stroke alone group). To model Aβ toxicity, rats received intracerebralventricular (icv) injections of the toxic 25-35 fragment of the Aβ peptide (Aβ alone group). To model the combination of Aβ toxicity with stroke, rats received both the unilateral ET-1 injection and the bilateral icv injections of Aβ₂₅₋₃₅ (combined Aβ/ET-1 group). By 3 d, a significant increase in the simple ganglioside species GM2 was observed in the ischemic brain region of rats who received a stroke (ET-1), with or without Aβ. By 21 d, GM2 levels only remained elevated in the combined Aβ/ET-1 group. GM3 levels however demonstrated a different pattern of expression. By 3 d GM3 was elevated in the ischemic brain region only in the combined Aβ/ET-1 group. By 21 d, GM3 was elevated in the ischemic brain region in both stroke alone and Aβ/ET-1 groups. Overall, results indicate that the accumulation of simple ganglioside species GM2 and GM3 may be indicative of a mechanism of interaction between AD and stroke. PMID:26086081

  2. Analysis of Slip Activity and Deformation Modes in Tension and Tension-Creep Tests of Cast Mg-10Gd-3Y-0.5Zr (Wt Pct) at Elevated Temperatures Using In Situ SEM Experiments

    NASA Astrophysics Data System (ADS)

    Wang, Huan; Boehlert, Carl J.; Wang, Qudong; Yin, Dongdi; Ding, Wenjiang

    2016-05-01

    The tension and tension-creep deformation behavior at elevated temperatures of a cast Mg-10Gd-3Y-0.5Zr (wt pct, GW103) alloy was investigated using in situ scanning electron microscopy. The tests were performed at temperatures ranging from 473 K to 598 K (200 °C to 325 °C). The active slip systems were identified using an EBSD-based slip trace analysis methodology. The results showed that for all of the tests, basal slip was the most likely system to be activated, and non-basal slip was activated to some extent depending on the temperature. No twinning was observed. For the tension tests, non-basal slip consisted of ~35 pct of the deformation modes at low temperatures (473 K and 523 K (200 °C and 250 °C)), while non-basal slip accounted for 12 and 7 pct of the deformation modes at high temperatures (573 K and 598 K (300 °C and 325 °C)), respectively. For the tension-creep tests, non-basal slip accounted for 31 pct of the total slip systems at low temperatures, while this value decreased to 10 to 16 pct at high temperatures. For a given temperature, the relative activity for prismatic slip in the tension-creep tests was slightly greater than that for the tension tests, while the activity for pyramidal slip was lower. Slip-transfer in neighboring grains was observed for the low-temperature tests. Intergranular cracking was the main cracking mode, while some intragranular cracks were observed for the tension-creep tests at high temperature and low stress. Grain boundary ledges were prevalently observed for both the tension and tension-creep tests at high temperatures, which suggests that besides dislocation slip, grain boundary sliding also contributed to the deformation.

  3. Role of Gd3+ ion on downshifting and upconversion emission properties of Pr3+, Yb3+ co-doped YNbO4 phosphor and sensitization effect of Bi3+ ion

    NASA Astrophysics Data System (ADS)

    Dwivedi, A.; Mishra, Kavita; Rai, S. B.

    2016-07-01

    Dual-mode luminescence (downshifting-DS and upconversion-UC) properties of Pr3+/Yb3+ co-doped Y1-xGdxNbO4 (x = 0.0, 0.5, and 1.0) phosphors synthesized by solid state reaction technique have been explored with and without Gd3+ ion. The structural characterizations (XRD, SEM, and FTIR) confirm the pure phase of YNbO4 phosphor. Further, with the Gd3+ ion co-doping, the YNbO4 phosphors having a random shape and the large particle size are found to be transformed into nearly spherical shape particles with the reduced particle size. The optical band gaps (Eg) of Y1-xGdxNbO4 (x = 0.00, 0.25, 0.50, and 1.00) calculated from UV-Vis-NIR measurements are ˜3.69, 4.00, 4.38, and 4.44 eV, respectively. Moreover, YNbO4 phosphor is a promising blue emitting material, whereas Y1-x-y-zPryYbzGdxNbO4 phosphor gives intense green, blue, and red emissions via dual-mode optical processes. The broad blue emission arises due to (NbO4)3- group of the host with λex = 264 nm, whereas Pr3+ doped YNbO4 phosphor gives dominant red and blue emissions along with comparatively weak green emission on excitation with λex = 300 nm and 491 nm. The concentration dependent variation in emission intensity at 491 nm (3P0→3H4 transition) and 612 nm (1D2→3H4 transition); at 612 nm (1D2→3H4 transition) and 658 nm (3P0→3F2 transition) of Pr3+ ion in YNbO4 phosphor with λex = 300 nm and 491 nm excitations, respectively, has been thoroughly explored and explained by the cross-relaxation process through different channels. The sensitization effect of Bi3+ ion co-doping on DS properties of the phosphor has also been studied. The observed DS results have been optimized by varying the concentration of Pr3+ and Bi3+ ions, and the results are explained by the well-known simple band structure model. The study of Gd3+ co-doping reveals noticeable differences in DS characteristics of Y1-xPrxNbO4 phosphors: the overall decrement and increment (except for 612 nm emission) in intensity of DS emission on

  4. Stimulation of a Ca sup 2+ -dependent protein kinase by G sub M1 ganglioside in nerve growth factor-treated PC12 cells

    SciTech Connect

    Hilbush, B.S.; Levine, J.M. )

    1991-07-01

    The authors have investigated the ability of exogenous gangliosides to modulate nerve growth factor (NGF) signal transduction in PC12 cells. The effects of exogenous ganglioside G{sub M1} on multiple protein kinase activities were assayed by analyzing site-specific serine phosphorylation of tyrosine hydroxylase (TyrOHase) by two-dimensional phosphopeptide mapping. In the presence of NGF, exogenous G{sub M1} increased {sup 32}P incorporation into TyrOHase phosphopeptide T2, a Ca{sup 2+}/calmodulin-dependent protein kinase substrate whose phosphorylation is not normally affected by NGF treatment. In the absence of NGF, G{sub M1} treatment had no significant effects on TyrOHase phosphorylation. The removal of extracellular Ca{sup 2+} or blockade of dihydropyridine-sensitive Ca{sup 2+} channels prevented the G{sub M1}-induced increases in {sup 32}P incorporation into phosphopeptide T2. Exogenous G{sub M1} also potentiated K{sup +} depolarization-induced increases in the phosphorylation of TyrOHase. These results suggest that the stimulatory effects of exogenous G{sub M1} ganglioside on NGF actions may be due to its ability to potentiate a Ca{sup 2+}-dependent signaling pathway.

  5. A New Assay for Determining Ganglioside Sialyltransferase Activities Lactosylceramide-2,3-Sialyltransferase (SAT I) and Monosialylganglioside-2,3-Sialyltransferase (SAT IV)

    PubMed Central

    Sun, Cynthia Q.; Hubl, Ulrike; Hoefakker, Petra; Vasudevamurthy, Madhusudan K.; Johnson, Keryn D.

    2014-01-01

    A new assay for the determination of lactosylceramide-2,3-sialyltransferase (SAT I, EC 2.4.99.9) and monosialoganglioside sialyltransferase (SAT IV, EC 2.4.99.2) is described. The assay utilised the commercially available fluorophore labelled sphingolipids, boron dipyrromethene difluoride (BODIPY) lactosylceramide (LacCer), and BODIPY-monosialotetrahexosylganglioside (GM1) as the acceptor substrates, for SAT I and SAT IV, respectively. HPLC coupled with fluorescence detection was used to analyse product formation. The analysis was performed in a quick and automated fashion. The assay showed good linearity for both BODIPY sphingolipids with a quantitative detection limit of 0.05 pmol. The high sensitivity enabled the detection of SAT I and SAT IV activities as low as 0.001 μU, at least 200 fold lower than that of most radiometric assays. This new assay was applied to the screening of SAT I and SAT IV activities in ovine and bovine organs (liver, heart, kidney, and spleen). The results provided evidence that young animals, such as calves, start to produce ganglioside sialyltransferases as early as 7 days after parturition and that levels change during maturation. Among the organs tested from a bovine source, spleen had the highest specific ganglioside sialyltransferase activity. Due to the organ size, the greatest total ganglioside sialyltransferase activities (SAT I and SAT IV) were detected in the liver of both bovine and ovine origin. PMID:24718572

  6. A new assay for determining ganglioside sialyltransferase activities lactosylceramide-2,3-sialyltransferase (SAT I) and monosialylganglioside-2,3-sialyltransferase (SAT IV).

    PubMed

    Sun, Cynthia Q; Hubl, Ulrike; Hoefakker, Petra; Vasudevamurthy, Madhusudan K; Johnson, Keryn D

    2014-01-01

    A new assay for the determination of lactosylceramide-2,3-sialyltransferase (SAT I, EC 2.4.99.9) and monosialoganglioside sialyltransferase (SAT IV, EC 2.4.99.2) is described. The assay utilised the commercially available fluorophore labelled sphingolipids, boron dipyrromethene difluoride (BODIPY) lactosylceramide (LacCer), and BODIPY-monosialotetrahexosylganglioside (GM1) as the acceptor substrates, for SAT I and SAT IV, respectively. HPLC coupled with fluorescence detection was used to analyse product formation. The analysis was performed in a quick and automated fashion. The assay showed good linearity for both BODIPY sphingolipids with a quantitative detection limit of 0.05 pmol. The high sensitivity enabled the detection of SAT I and SAT IV activities as low as 0.001 μU, at least 200 fold lower than that of most radiometric assays. This new assay was applied to the screening of SAT I and SAT IV activities in ovine and bovine organs (liver, heart, kidney, and spleen). The results provided evidence that young animals, such as calves, start to produce ganglioside sialyltransferases as early as 7 days after parturition and that levels change during maturation. Among the organs tested from a bovine source, spleen had the highest specific ganglioside sialyltransferase activity. Due to the organ size, the greatest total ganglioside sialyltransferase activities (SAT I and SAT IV) were detected in the liver of both bovine and ovine origin. PMID:24718572

  7. Analysis and optimization of interactions between peptides mimicking the GD2 ganglioside and the monoclonal antibody 14G2a.

    PubMed

    Horwacik, Irena; Kurciński, Mateusz; Bzowska, Małgorzata; Kowalczyk, Aleksandra K; Czaplicki, Dominik; Koliński, Andrzej; Rokita, Hanna

    2011-07-01

    Overexpression of the GD2 ganglioside (GD2) is a hallmark of neuroblastoma. The antigen is used in neuroblastoma diagnosis and to target newly developed therapies to cancer cells. Peptide mimetics are novel approaches in the design of antigens for vaccine development. We previously reported the isolation of five GD2-mimicking peptides from the LX-8 phage display library with the monoclonal antibody (mAb) 14G2a. The goal of our current study was to analyze and optimize the binding of the peptide mimetics to the mAb 14G2a. Therefore, we performed further experiments and supported them with molecular modeling to investigate structure-activity relationships that are the basis for the observed mimicry of GD2 by our peptides. Here, we show that the peptides have overlapping binding sites on the mAb, 14G2a and restricted specificity, as they did not crossreact with other ganglioside-specific antibodies tested. In addition we demonstrate that the phage environment was involved in the process of selection of our peptides. The AAEGD sequence taken from the viral major coat protein, p8, and added to the C-termini of the peptides #65, #85 and #94 significantly improved their binding to the mAb, 14G2a. By application of analogs with amino acid substitutions and sequence truncations, we elucidated the structure-activity relationships necessary for the interactions between the 14G2a mAb and the peptide #94 (RCNPNMEPPRCF). We identified amino acids indispensable for the observed GD2-mimicry by #94 and confirmed a pivotal role of the disulphide bridge between the cysteine residues of #94 for binding to the mAb 14G2a. More importantly, we report five new peptides demonstrating a significant improvement of mAb 14G2a binding. The experimental data were supported and expanded with molecular modeling tools. Taken together, the experimental results and the in silico data allowed us to probe in detail the mechanism of the molecular mimicry of GD2 by the peptides. Additionally, we

  8. Prognostic Role of 14F7 Mab Immunoreactivity against N-Glycolyl GM3 Ganglioside in Colon Cancer

    PubMed Central

    Calvo, Adanays; Torres, Griselda; Rengifo, Charles E.; Quintero, Santiago; Arango, María del Carmen; Danta, Debora; Vázquez, José M.; Escobar, Xiomara; Carr, Adriana

    2014-01-01

    Purpose. To assess the prognostic role of 14F7 Mab immunoreactivity, against N-Glycolyl GM3 ganglioside, in patients with colon cancer (CC) and to evaluate the relationship between its expression and clinicopathological features. Methods. Paraffin-embedded specimens were retrospectively collected from 50 patients with CC operated between 2004 and 2008. 14F7 Mab staining was determined by immunohistochemistry technique and its relation with survival and clinicopathologic features was evaluated. Results. The reactivity of 14F7 Mab was detected in all cases. Most cases had high level of immunostaining (70%) that showed statistical correlation with TNM stage (P = 0.025). In univariate survival analysis, level of 14F7 Mab immunoreactivity (P = 0.0078), TNM Stage (P = 0.0007) and lymphovascular invasion (0.027) were significant prognostic factors for overall survival. Among these variables, level of 14F7 Mab immunoreactivity (HR = 0.268; 95% CI  0.078–0.920; P = 0.036) and TNM stage (HR = 0.249; 95% CI 0.066–0.932; P = 0.039) were independent prognostic factors on multivariate analysis. Conclusions. This study is the first approach on the prognostic significance of 14F7 Mab immunoreactivity in patients with colon adenocarcinoma and this assessment might be used in the prognostic estimate of CC, although further studies will be required to validate these findings. PMID:24639871

  9. Structure-Activity Relationship Study of the Neuritogenic Potential of the Glycan of Starfish Ganglioside LLG-3 ‡

    PubMed Central

    Yamagishi, Megumi; Hosoda-Yabe, Ritsuko; Tamai, Hideki; Konishi, Miku; Imamura, Akihiro; Ishida, Hideharu; Yabe, Tomio; Ando, Hiromune; Kiso, Makoto

    2015-01-01

    LLG-3 is a ganglioside isolated from the starfish Linchia laevigata. To clarify the structure-activity relationship of the glycan of LLG-3 toward rat pheochromocytoma PC12 cells in the presence of nerve growth factor, a series of mono- to tetrasaccharide glycan derivatives were chemically synthesized and evaluated in vitro. The methyl group at C8 of the terminal sialic acid residue was crucial for neuritogenic activity, and the terminal trisaccharide moiety was the minimum active motif. Furthermore, the trisaccharide also stimulated neuritogenesis in human neuroblastoma SH-SY5Y cells via mitogen-activated protein kinase (MAPK) signaling. Phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 was rapidly induced by adding 1 or 10 nM of the trisaccharide. The ratio of phosphorylated ERK to ERK reached a maximum 5 min after stimulation, and then decreased gradually. However, the trisaccharide did not induce significant Akt phosphorylation. These effects were abolished by pretreatment with the MAPK inhibitor U0126, which inhibits enzymes MEK1 and MEK2. In addition, U0126 inhibited the phosphorylation of ERK 1/2 in response to the trisaccharide dose-dependently. Therefore, we concluded that the trisaccharide promotes neurite extension in SH-SY5Y cells via MAPK/ERK signaling, not Akt signaling. PMID:26690179

  10. The ganglioside antigen GD2 is surface-expressed in Ewing sarcoma and allows for MHC-independent immune targeting

    PubMed Central

    Kailayangiri, S; Altvater, B; Meltzer, J; Pscherer, S; Luecke, A; Dierkes, C; Titze, U; Leuchte, K; Landmeier, S; Hotfilder, M; Dirksen, U; Hardes, J; Gosheger, G; Juergens, H; Rossig, C

    2012-01-01

    Background: Novel treatment strategies are needed to cure disseminated Ewing sarcoma. Primitive neuroectodermal features and a mesenchymal stem cell origin are both compatible with aberrant expression of the ganglioside antigen GD2 and led us to explore GD2 immune targeting in this cancer. Methods: We investigated GD2 expression in Ewing sarcoma by immunofluorescence staining. We then assessed the antitumour activity of T cells expressing a chimeric antigen receptor specific for GD2 against Ewing sarcoma in vitro and in vivo. Results: Surface GD2 was detected in 10 out of 10 Ewing sarcoma cell lines and 3 out of 3 primary cell cultures. Moreover, diagnostic biopsies from 12 of 14 patients had uniform GD2 expression. T cells specifically modified to express the GD2-specific chimeric receptor 14. G2a-28ζ efficiently interacted with Ewing sarcoma cells, resulting in antigen-specific secretion of cytokines. Moreover, chimeric receptor gene-modified T cells from healthy donors and from a patient exerted potent, GD2-specific cytolytic responses to allogeneic and autologous Ewing sarcoma, including tumour cells grown as multicellular, anchorage-independent spheres. GD2-specific T cells further had activity against Ewing sarcoma xenografts. Conclusion: GD2 surface expression is a characteristic of Ewing sarcomas and provides a suitable target antigen for immunotherapeutic strategies to eradicate micrometastatic cells and prevent relapse in high-risk disease. PMID:22374462

  11. Differential uPAR recruitment in caveolar-lipid rafts by GM1 and GM3 gangliosides regulates endothelial progenitor cells angiogenesis.

    PubMed

    Margheri, Francesca; Papucci, Laura; Schiavone, Nicola; D'Agostino, Riccardo; Trigari, Silvana; Serratì, Simona; Laurenzana, Anna; Biagioni, Alessio; Luciani, Cristina; Chillà, Anastasia; Andreucci, Elena; Del Rosso, Tommaso; Margheri, Giancarlo; Del Rosso, Mario; Fibbi, Gabriella

    2015-01-01

    Gangliosides and the urokinase plasminogen activator receptor (uPAR) tipically partition in specialized membrane microdomains called lipid-rafts. uPAR becomes functionally important in fostering angiogenesis in endothelial progenitor cells (EPCs) upon recruitment in caveolar-lipid rafts. Moreover, cell membrane enrichment with exogenous GM1 ganglioside is pro-angiogenic and opposite to the activity of GM3 ganglioside. On these basis, we first checked the interaction of uPAR with membrane models enriched with GM1 or GM3, relying on the adoption of solid-supported mobile bilayer lipid membranes with raft-like composition formed onto solid hydrophilic surfaces, and evaluated by surface plasmon resonance (SPR) the extent of uPAR recruitment. We estimated the apparent dissociation constants of uPAR-GM1/GM3 complexes. These preliminary observations, indicating that uPAR binds preferentially to GM1-enriched biomimetic membranes, were validated by identifying a pro-angiogenic activity of GM1-enriched EPCs, based on GM1-dependent uPAR recruitment in caveolar rafts. We have observed that addition of GM1 to EPCs culture medium promotes matrigel invasion and capillary morphogenesis, as opposed to the anti-angiogenesis activity of GM3. Moreover, GM1 also stimulates MAPKinases signalling pathways, typically associated with an angiogenesis program. Caveolar-raft isolation and Western blotting of uPAR showed that GM1 promotes caveolar-raft partitioning of uPAR, as opposed to control and GM3-challenged EPCs. By confocal microscopy, we have shown that in EPCs uPAR is present on the surface in at least three compartments, respectively, associated to GM1, GM3 and caveolar rafts. Following GM1 exogenous addition, the GM3 compartment is depleted of uPAR which is recruited within caveolar rafts thereby triggering angiogenesis. PMID:25313007

  12. Differential uPAR recruitment in caveolar-lipid rafts by GM1 and GM3 gangliosides regulates endothelial progenitor cells angiogenesis

    PubMed Central

    Margheri, Francesca; Papucci, Laura; Schiavone, Nicola; D'Agostino, Riccardo; Trigari, Silvana; Serratì, Simona; Laurenzana, Anna; Biagioni, Alessio; Luciani, Cristina; Chillà, Anastasia; Andreucci, Elena; Del Rosso, Tommaso; Margheri, Giancarlo; Del Rosso, Mario; Fibbi, Gabriella

    2015-01-01

    Gangliosides and the urokinase plasminogen activator receptor (uPAR) tipically partition in specialized membrane microdomains called lipid-rafts. uPAR becomes functionally important in fostering angiogenesis in endothelial progenitor cells (EPCs) upon recruitment in caveolar-lipid rafts. Moreover, cell membrane enrichment with exogenous GM1 ganglioside is pro-angiogenic and opposite to the activity of GM3 ganglioside. On these basis, we first checked the interaction of uPAR with membrane models enriched with GM1 or GM3, relying on the adoption of solid-supported mobile bilayer lipid membranes with raft-like composition formed onto solid hydrophilic surfaces, and evaluated by surface plasmon resonance (SPR) the extent of uPAR recruitment. We estimated the apparent dissociation constants of uPAR-GM1/GM3 complexes. These preliminary observations, indicating that uPAR binds preferentially to GM1-enriched biomimetic membranes, were validated by identifying a pro-angiogenic activity of GM1-enriched EPCs, based on GM1-dependent uPAR recruitment in caveolar rafts. We have observed that addition of GM1 to EPCs culture medium promotes matrigel invasion and capillary morphogenesis, as opposed to the anti-angiogenesis activity of GM3. Moreover, GM1 also stimulates MAPKinases signalling pathways, typically associated with an angiogenesis program. Caveolar-raft isolation and Western blotting of uPAR showed that GM1 promotes caveolar-raft partitioning of uPAR, as opposed to control and GM3-challenged EPCs. By confocal microscopy, we have shown that in EPCs uPAR is present on the surface in at least three compartments, respectively, associated to GM1, GM3 and caveolar rafts. Following GM1 exogenous addition, the GM3 compartment is depleted of uPAR which is recruited within caveolar rafts thereby triggering angiogenesis. PMID:25313007

  13. Binding of monoclonal antibody AA4 to gangliosides on rat basophilic leukemia cells produces changes similar to those seen with Fc epsilon receptor activation

    PubMed Central

    1992-01-01

    The mAb AA4 binds to novel derivatives of the ganglioside Gd1b on rat basophilic leukemia (RBL-2H3) cells. Some of the gangliosides are located close to the high affinity IgE receptor (Fc epsilon RI), and binding of mAb AA4 inhibits Fc epsilon RI-mediated histamine release. In the present study, mAb AA4 was found to bind exclusively to mast cells in all rat tissues examined. In vitro, within 1 min of mAb AA4 binding, the cells underwent striking morphologic changes. They lost their normal spindle shaped appearance, increased their ruffling, and spread over the surface of the culture dish. These changes were accompanied by a redistribution of the cytoskeletal elements, actin, tubulin, and vimentin, but only the actin was associated with the membrane ruffles. Binding of mAb AA4 also induces a rise in intracellular calcium, stimulates phosphatidyl inositol breakdown, and activates PKC. However, the extent of these changes was less than that observed when the cells were stimulated with antigen or antibody directed against the Fc epsilon RI. None of these changes associated with mAb AA4 binding were seen when the cells were exposed to nonspecific IgG, IgE, or four other anti-cell surface antibodies, nor were the changes induced by binding mAb AA4 at 4 degrees C or in the absence of extracellular calcium. Although mAb AA4 does not stimulate histamine release, it enhances the effect of the calcium ionophore A23187 mediated release. The morphological and biochemical effects produced by mAb AA4 are similar to those seen following activation of the cell through the IgE receptor. Therefore, the surface gangliosides which bind mAb AA4 may function in modulating secretory events. PMID:1370498

  14. Association of antibodies to ganglioside complexes and conduction blocks in axonal Guillain-Barré syndrome presenting as acute motor conduction block neuropathy.

    PubMed

    Créange, Alain; Shahrizaila, Nortina; Salhi, Hayet; Lefaucheur, Jean-Pascal; Yuki, Nobuhiro

    2014-06-01

    A close relationship between acute motor conduction block neuropathy and antibodies against the complex of GM1 and GalNAc-GD1a has been reported. This study investigates the hypothesis that conduction block at the early phase of axonal Guillain-Barré syndrome (GBS) is also associated with such ganglioside complexes. Sera were obtained from seven French patients with initial evidence of isolated conduction blocks that resolved or progressed to acute motor axonal neuropathy. Serum IgG to asialo-GM1 and gangliosides of LM1, GM1, GM1b, GD1a, GalNAc-GD1a, GD1b, GT1a, GT1b, and GQ1b as well as their complexes were measured. Five of seven patients progressed within the first month of disease to AMAN. One patient had IgG antibodies against the complex of asialo-GM1 and each of the other ganglioside antigens. Another patient carried IgG antibodies against GM1 complex with GM1b, GD1a, and GT1a as well as asialo-GM1 complex with GD1a and GT1a. None had IgG antibodies against GM1/GalNAc-GD1a complex. Six patients had IgG against single antigens GM1, GD1a, GalNAc-GD1a, GD1b, and asialo-GM1. In three patients, a reduced reaction against GM1/GalNAc-GD1a complex was observed. The presence of conduction block in axonal GBS is not always associated with anti-GM1/GalNAc-GD1a complex antibodies.

  15. Analysis of genes involved in response to doxorubicin and a GD2 ganglioside-specific 14G2a monoclonal antibody in IMR-32 human neuroblastoma cells.

    PubMed

    Horwacik, Irena; Durbas, Małgorzata; Boratyn, Elżbieta; Sawicka, Anna; Węgrzyn, Paulina; Krzanik, Sylwia; Górka, Anna; Drożniak, Joanna; Augustyniak, Ewa; Kowalczyk, Aleksandra; Rokita, Hanna

    2015-01-01

    Neuroblastoma is the most common extra-cranial solid tumor of childhood and it is characterized by the presence of a glycosphingolipid, GD2 ganglioside. Monoclonal antibodies targeting the antigen are currently tested in clinical trials. Additionally, several research groups reported results revealing that ganglioside-specific antibodies can affect cellular signaling and cause direct cytotoxicity against tumor cells. To shed more light on gene expression signatures of tumor cells, we used microarrays to analyze changes of transcriptome in IMR-32 human neuroblastoma cell cultures treated with doxorubicin (DOX) or a mouse monoclonal antibody binding to GD2 ganglioside 14G2a (mAb) for 24 h. The obtained results highlight that disparate cellular pathways are regulated by doxorubicin and 14G2a. Next, we used RT-PCR to verify mRNA levels of selected DOX-responsive genes such as RPS27L, PPM1D, SESN1, CDKN1A, TNFSF10B, and 14G2a-responsive genes such as SVIL, JUN, RASSF6, TLX2, ID1. Then, we applied western blot and analyzed levels of RPS27L, PPM1D, sestrin 1 proteins after DOX-treatment. Additionally, we aimed to measure effects of doxorubicin and topotecan (TPT) and 14G2a on expression of a novel human NDUFAF2 gene encoding for mimitin protein (MYC-induced mitochondrial protein) and correlate it with expression of the MYCN gene. We showed that expression of both genes was concomitantly decreased in the 14G2a-treated IMR-32 cells after 24 h and 48 h. Our results extend knowledge on gene expression profiles after application of DOX and 14G2a in our model and reveal promising candidates for further research aimed at finding novel anti-neuroblastoma targets. PMID:26284262

  16. Differential uPAR recruitment in caveolar-lipid rafts by GM1 and GM3 gangliosides regulates endothelial progenitor cells angiogenesis.

    PubMed

    Margheri, Francesca; Papucci, Laura; Schiavone, Nicola; D'Agostino, Riccardo; Trigari, Silvana; Serratì, Simona; Laurenzana, Anna; Biagioni, Alessio; Luciani, Cristina; Chillà, Anastasia; Andreucci, Elena; Del Rosso, Tommaso; Margheri, Giancarlo; Del Rosso, Mario; Fibbi, Gabriella

    2015-01-01

    Gangliosides and the urokinase plasminogen activator receptor (uPAR) tipically partition in specialized membrane microdomains called lipid-rafts. uPAR becomes functionally important in fostering angiogenesis in endothelial progenitor cells (EPCs) upon recruitment in caveolar-lipid rafts. Moreover, cell membrane enrichment with exogenous GM1 ganglioside is pro-angiogenic and opposite to the activity of GM3 ganglioside. On these basis, we first checked the interaction of uPAR with membrane models enriched with GM1 or GM3, relying on the adoption of solid-supported mobile bilayer lipid membranes with raft-like composition formed onto solid hydrophilic surfaces, and evaluated by surface plasmon resonance (SPR) the extent of uPAR recruitment. We estimated the apparent dissociation constants of uPAR-GM1/GM3 complexes. These preliminary observations, indicating that uPAR binds preferentially to GM1-enriched biomimetic membranes, were validated by identifying a pro-angiogenic activity of GM1-enriched EPCs, based on GM1-dependent uPAR recruitment in caveolar rafts. We have observed that addition of GM1 to EPCs culture medium promotes matrigel invasion and capillary morphogenesis, as opposed to the anti-angiogenesis activity of GM3. Moreover, GM1 also stimulates MAPKinases signalling pathways, typically associated with an angiogenesis program. Caveolar-raft isolation and Western blotting of uPAR showed that GM1 promotes caveolar-raft partitioning of uPAR, as opposed to control and GM3-challenged EPCs. By confocal microscopy, we have shown that in EPCs uPAR is present on the surface in at least three compartments, respectively, associated to GM1, GM3 and caveolar rafts. Following GM1 exogenous addition, the GM3 compartment is depleted of uPAR which is recruited within caveolar rafts thereby triggering angiogenesis.

  17. Relative Roles of GM1 Ganglioside, N-Acylneuraminic Acids, and α2β1 Integrin in Mediating Rotavirus Infection

    PubMed Central

    Fleming, Fiona E.; Böhm, Raphael; Dang, Vi T.; Holloway, Gavan; Haselhorst, Thomas; Madge, Paul D.; Deveryshetty, Jaigeeth; Yu, Xing; Blanchard, Helen; von Itzstein, Mark

    2014-01-01

    ABSTRACT N-acetyl- and N-glycolylneuraminic acids (Sia) and α2β1 integrin are frequently used by rotaviruses as cellular receptors through recognition by virion spike protein VP4. The VP4 subunit VP8*, derived from Wa rotavirus, binds the internal N-acetylneuraminic acid on ganglioside GM1. Wa infection is increased by enhanced internal Sia access following terminal Sia removal from main glycan chains with sialidase. The GM1 ligand cholera toxin B (CTB) reduces Wa infectivity. Here, we found sialidase treatment increased cellular GM1 availability and the infectivity of several other human (including RV-3) and animal rotaviruses, typically rendering them susceptible to methyl α-d-N-acetylneuraminide treatment, but did not alter α2β1 usage. CTB reduced the infectivity of these viruses. Aceramido-GM1 inhibited Wa and RV-3 infectivity in untreated and sialidase-treated cells, and GM1 supplementation increased their infectivity, demonstrating the importance of GM1 for infection. Wa recognition of α2β1 and internal Sia were at least partially independent. Rotavirus usage of GM1 was mapped to VP4 using virus reassortants, and RV-3 VP8* bound aceramido-GM1 by saturation transfer difference nuclear magnetic resonance (STD NMR). Most rotaviruses recognizing terminal Sia did not use GM1, including RRV. RRV VP8* interacted minimally with aceramido-GM1 by STD NMR. Unusually, TFR-41 rotavirus infectivity depended upon terminal Sia and GM1. Competition of CTB, Sia, and/or aceramido-GM1 with cell binding by VP8* from representative rotaviruses showed that rotavirus Sia and GM1 preferences resulted from VP8*-cell binding. Our major finding is that infection by human rotaviruses of commonly occurring VP4 serotypes involves VP8* binding to cell surface GM1 glycan, typically including the internal N-acetylneuraminic acid. IMPORTANCE Rotaviruses, the major cause of severe infantile gastroenteritis, recognize cell surface receptors through virus spike protein VP4. Several animal

  18. Endothelin A Receptor Antagonism Enhances Inhibitory Effects of Anti-Ganglioside GD2 Monoclonal Antibody on Invasiveness and Viability of Human Osteosarcoma Cells

    PubMed Central

    Liu, Bo; Wu, Yi; Zhou, Yu; Peng, Dan

    2014-01-01

    Endothelin-1 (ET-1)/endothelin A receptor (ETAR) signaling is important for osteosarcoma (OS) progression. Monoclonal antibodies (mAbs) targeting ganglioside GD2 reportedly inhibit tumor cell viability independent of the immune system. A recent study suggests that ganglioside GD2 may play an important role in OS progression. In the present study, we for the first time explored the effects of anti-GD2 mAb alone or in combination with ETAR antagonist on OS cell invasiveness and viability. Human OS cell lines Saos-2, MG-63 and SJSA-1 were treated with control IgG (PK136 mAb, 50 µg/mL), anti-GD2 14G2a mAb (50 µg/mL), selective ETAR antagonist BQ123 (5 µM), or 14G2a (50 µg/mL)+BQ123 (5 µM). Cells with knockdown of ETAR (ETAR-shRNA) with or without 14G2a mAb treatment were also tested. Cells treated with selective phosphatidylinositide 3-kinase (PI3K) inhibitor BKM120 (50 µM) were used as a positive control. Our results showed that BQ123, ETAR-shRNA and 14G2a mAb individually decreased cell invasion and viability, matrix metalloproteinase-2 (MMP-2) expression and activity, PI3k activity, and phosphorylation at serine 473 (ser473) of Akt in OS cells. 14G2a mAb in combination with BQ123 or ETAR-shRNA showed significantly stronger inhibitory effects compared with each individual treatment. In all three cell lines tested, 14G2a mAb in combination with BQ123 showed the strongest inhibitory effects. In conclusion, we provide the first in vitro evidence that anti-ganglioside GD2 14G2a mAb effectively inhibits cell invasiveness, MMP-2 expression and activity, and cell viability in human OS cells. ETAR antagonist BQ123 significantly enhances the inhibitory effects of 14G2a mAb, likely mainly through inhibiting the PI3K/Akt pathway. This study adds novel insights into OS treatment, which will serve as a solid basis for future in vivo studies on the effects of combined treatment of OS with anti-ganglioside GD2 mAbs and ETAR antagonists. PMID:24727660

  19. Endothelin A receptor antagonism enhances inhibitory effects of anti-ganglioside GD2 monoclonal antibody on invasiveness and viability of human osteosarcoma cells.

    PubMed

    Liu, Bo; Wu, Yi; Zhou, Yu; Peng, Dan

    2014-01-01

    Endothelin-1 (ET-1)/endothelin A receptor (ETAR) signaling is important for osteosarcoma (OS) progression. Monoclonal antibodies (mAbs) targeting ganglioside GD2 reportedly inhibit tumor cell viability independent of the immune system. A recent study suggests that ganglioside GD2 may play an important role in OS progression. In the present study, we for the first time explored the effects of anti-GD2 mAb alone or in combination with ETAR antagonist on OS cell invasiveness and viability. Human OS cell lines Saos-2, MG-63 and SJSA-1 were treated with control IgG (PK136 mAb, 50 µg/mL), anti-GD2 14G2a mAb (50 µg/mL), selective ETAR antagonist BQ123 (5 µM), or 14G2a (50 µg/mL)+BQ123 (5 µM). Cells with knockdown of ETAR (ETAR-shRNA) with or without 14G2a mAb treatment were also tested. Cells treated with selective phosphatidylinositide 3-kinase (PI3K) inhibitor BKM120 (50 µM) were used as a positive control. Our results showed that BQ123, ETAR-shRNA and 14G2a mAb individually decreased cell invasion and viability, matrix metalloproteinase-2 (MMP-2) expression and activity, PI3k activity, and phosphorylation at serine 473 (ser473) of Akt in OS cells. 14G2a mAb in combination with BQ123 or ETAR-shRNA showed significantly stronger inhibitory effects compared with each individual treatment. In all three cell lines tested, 14G2a mAb in combination with BQ123 showed the strongest inhibitory effects. In conclusion, we provide the first in vitro evidence that anti-ganglioside GD2 14G2a mAb effectively inhibits cell invasiveness, MMP-2 expression and activity, and cell viability in human OS cells. ETAR antagonist BQ123 significantly enhances the inhibitory effects of 14G2a mAb, likely mainly through inhibiting the PI3K/Akt pathway. This study adds novel insights into OS treatment, which will serve as a solid basis for future in vivo studies on the effects of combined treatment of OS with anti-ganglioside GD2 mAbs and ETAR antagonists. PMID:24727660

  20. A natural human IgM that binds to gangliosides is therapeutic in murine models of amyotrophic lateral sclerosis

    PubMed Central

    Xu, Xiaohua; Denic, Aleksandar; Jordan, Luke R.; Wittenberg, Nathan J.; Warrington, Arthur E.; Wootla, Bharath; Papke, Louisa M.; Zoecklein, Laurie J.; Yoo, Daehan; Shaver, Jonah; Oh, Sang-Hyun; Pease, Larry R.; Rodriguez, Moses

    2015-01-01

    ABSTRACT Amyotrophic lateral sclerosis (ALS) is a devastating, fatal neurological disease that primarily affects spinal cord anterior horn cells and their axons for which there is no treatment. Here we report the use of a recombinant natural human IgM that binds to the surface of neurons and supports neurite extension, rHIgM12, as a therapeutic strategy in murine models of human ALS. A single 200 µg intraperitoneal dose of rHIgM12 increases survival in two independent genetic-based mutant SOD1 mouse strains (SOD1G86R and SOD1G93A) by 8 and 10 days, delays the onset of neurological deficits by 16 days, delays the onset of weight loss by 5 days, and preserves spinal cord axons and anterior horn neurons. Immuno-overlay of thin layer chromatography and surface plasmon resonance show that rHIgM12 binds with high affinity to the complex gangliosides GD1a and GT1b. Addition of rHIgM12 to neurons in culture increases α-tubulin tyrosination levels, suggesting an alteration of microtubule dynamics. We previously reported that a single peripheral dose of rHIgM12 preserved neurological function in a murine model of demyelination with axon loss. Because rHIgM12 improves three different models of neurological disease, we propose that the IgM might act late in the cascade of neuronal stress and/or death by a broad mechanism. PMID:26035393

  1. Prognostic Significance of N-Glycolyl GM3 Ganglioside Expression in Non-Small Cell Lung Carcinoma Patients: New Evidences

    PubMed Central

    Blanco, Rancés; Domínguez, Elizabeth; Morales, Orlando; Blanco, Damián; Martínez, Darel; Rengifo, Charles E.; Viada, Carmen; Cedeño, Mercedes; Rengifo, Enrique; Carr, Adriana

    2015-01-01

    The prognostic role of N-glycolyl GM3 ganglioside (NeuGcGM3) expression in non-small cell lung carcinoma (NSCLC) still remains controversial. In this study, the NeuGcGM3 expression was reevaluated using an increased number of NSCLC cases and the 14F7 Mab (a highly specific IgG1 raised against NeuGcGM3). An immunohistochemical score integrating the percentage of 14F7-positive cells and the intensity of reaction was applied to reassess the relationship between NeuGcGM3 expression, some clinicopathological features, and the overall survival (OS) of NSCLC patients. The double and the triple expression of NeuGcGM3 with the epidermal growth factor receptor (EGFR) and/or its ligand, the epidermal growth factor (EGF), were also evaluated. NeuGcGM3 expression correlates with both S-Phase fraction (p = 0.006) and proliferation index (p = 0.000). Additionally, NeuGcGM3 expression was associated with a poor OS of patients in both univariate (p = 0.020) and multivariate (p = 0.010) analysis. Moreover, the double and/or the triple positivity of tumors to NeuGcGM3, EGFR, and/or EGF permitted us to identify phenotypes of NSCLC with a more aggressive biological behavior. Our results are in agreement with the negative prognostic significance of NeuGcGM3 expression in NSCLC patients. However, standardization of techniques to determine the expression of NeuGcGM3 in NSCLC as well as the implementation of a universal scoring system is recommended. PMID:26634172

  2. Treatment of neuroblastoma meningeal carcinomatosis with intrathecal application of alpha-emitting atomic nanogenerators targeting disialo-ganglioside GD2.

    PubMed

    Miederer, Matthias; McDevitt, Michael R; Borchardt, Paul; Bergman, Ira; Kramer, Kim; Cheung, Nai-Kong V; Scheinberg, David A

    2004-10-15

    Labeling of specific antibodies with bifunctional chelated Actinium-225 ((225)Ac; an alpha generator) allows the formation of new, highly potent and selective alpha-emitting anticancer drugs. We synthesized and evaluated a radioimmunoconjugate based on 3F8, an IgG(3) antibody that specifically binds to ganglioside GD2, which is overexpressed by many neuroectodermal tumors including neuroblastoma. The (225)Ac-1,4,7,10-tetra-azacylododecane (DOTA)-3F8 construct was evaluated for radiochemical purity and sterility, immunoreactivity, cytotoxicity in vitro, induction of apoptosis on GD2-positive cells, as well as for pharmacological biodistribution and metabolism of the (225)Ac generator and its daughters in a nude mouse xenograft model of neuroblastoma. The (225)Ac-3F8 showed an IC(50) of 3 Bq/ml (80 pCi/ml) on the neuroblastoma cell line, NMB7, in vitro. Apoptosis of these cells was not observed. Biodistribution in mice showed specific targeting of a subcutaneous tumor; there was redistribution of the (225)Ac daughter nuclides mainly from blood to kidneys and to small intestine. Toxicity was examined in cynomolgus monkeys. Monkeys injected with 1 to 3 doses of intrathecal (225)Ac-3F8 radioimmunoconjugate (80 to 150 kBq/kg total dose) did not show signs of toxicity based on blood chemistry, complete blood counts, or by clinical evaluations. Therapeutic efficacy of intrathecal (225)Ac-3F8 was studied in a nude rat xenograft model of meningeal carcinomatosis. The (225)Ac-3F8 treatment improved survival 2-fold from 16 to 34 days (P = 0.01). In conclusion, in vivo alpha generators targeted by 3F8 warrant additional study as a possible new approach to the treatment of carcinomatous meningitis.

  3. Interaction between Simian Virus 40 Major Capsid Protein VP1 and Cell Surface Ganglioside GM1 Triggers Vacuole Formation

    PubMed Central

    Luo, Yong; Motamedi, Nasim; Magaldi, Thomas G.; Gee, Gretchen V.; Atwood, Walter J.

    2016-01-01

    ABSTRACT Simian virus 40 (SV40), a polyomavirus that has served as an important model to understand many aspects of biology, induces dramatic cytoplasmic vacuolization late during productive infection of monkey host cells. Although this activity led to the discovery of the virus in 1960, the mechanism of vacuolization is still not known. Pentamers of the major SV40 capsid protein VP1 bind to the ganglioside GM1, which serves as the cellular receptor for the virus. In this report, we show that binding of VP1 to cell surface GM1 plays a key role in SV40 infection-induced vacuolization. We previously showed that SV40 VP1 mutants defective for GM1 binding fail to induce vacuolization, even though they replicate efficiently. Here, we show that interfering with GM1-VP1 binding by knockdown of GM1 after infection is established abrogates vacuolization by wild-type SV40. Vacuole formation during permissive infection requires efficient virus release, and conditioned medium harvested late during SV40 infection rapidly induces vacuoles in a VP1- and GM1-dependent fashion. Furthermore, vacuolization can also be induced by a nonreplicating SV40 pseudovirus in a GM1-dependent manner, and a mutation in BK pseudovirus VP1 that generates GM1 binding confers vacuole-inducing activity. Vacuolization can also be triggered by purified pentamers of wild-type SV40 VP1, but not by GM1 binding-defective pentamers or by intracellular expression of VP1. These results demonstrate that SV40 infection-induced vacuolization is caused by the binding of released progeny viruses to GM1, thereby identifying the molecular trigger for the activity that led to the discovery of SV40. PMID:27006465

  4. Treatment of neuroblastoma meningeal carcinomatosis with intrathecal application of alpha-emitting atomic nanogenerators targeting disialo-ganglioside GD2.

    PubMed

    Miederer, Matthias; McDevitt, Michael R; Borchardt, Paul; Bergman, Ira; Kramer, Kim; Cheung, Nai-Kong V; Scheinberg, David A

    2004-10-15

    Labeling of specific antibodies with bifunctional chelated Actinium-225 ((225)Ac; an alpha generator) allows the formation of new, highly potent and selective alpha-emitting anticancer drugs. We synthesized and evaluated a radioimmunoconjugate based on 3F8, an IgG(3) antibody that specifically binds to ganglioside GD2, which is overexpressed by many neuroectodermal tumors including neuroblastoma. The (225)Ac-1,4,7,10-tetra-azacylododecane (DOTA)-3F8 construct was evaluated for radiochemical purity and sterility, immunoreactivity, cytotoxicity in vitro, induction of apoptosis on GD2-positive cells, as well as for pharmacological biodistribution and metabolism of the (225)Ac generator and its daughters in a nude mouse xenograft model of neuroblastoma. The (225)Ac-3F8 showed an IC(50) of 3 Bq/ml (80 pCi/ml) on the neuroblastoma cell line, NMB7, in vitro. Apoptosis of these cells was not observed. Biodistribution in mice showed specific targeting of a subcutaneous tumor; there was redistribution of the (225)Ac daughter nuclides mainly from blood to kidneys and to small intestine. Toxicity was examined in cynomolgus monkeys. Monkeys injected with 1 to 3 doses of intrathecal (225)Ac-3F8 radioimmunoconjugate (80 to 150 kBq/kg total dose) did not show signs of toxicity based on blood chemistry, complete blood counts, or by clinical evaluations. Therapeutic efficacy of intrathecal (225)Ac-3F8 was studied in a nude rat xenograft model of meningeal carcinomatosis. The (225)Ac-3F8 treatment improved survival 2-fold from 16 to 34 days (P = 0.01). In conclusion, in vivo alpha generators targeted by 3F8 warrant additional study as a possible new approach to the treatment of carcinomatous meningitis. PMID:15501978

  5. A natural human IgM that binds to gangliosides is therapeutic in murine models of amyotrophic lateral sclerosis.

    PubMed

    Xu, Xiaohua; Denic, Aleksandar; Jordan, Luke R; Wittenberg, Nathan J; Warrington, Arthur E; Wootla, Bharath; Papke, Louisa M; Zoecklein, Laurie J; Yoo, Daehan; Shaver, Jonah; Oh, Sang-Hyun; Pease, Larry R; Rodriguez, Moses

    2015-08-01

    Amyotrophic lateral sclerosis (ALS) is a devastating, fatal neurological disease that primarily affects spinal cord anterior horn cells and their axons for which there is no treatment. Here we report the use of a recombinant natural human IgM that binds to the surface of neurons and supports neurite extension, rHIgM12, as a therapeutic strategy in murine models of human ALS. A single 200 µg intraperitoneal dose of rHIgM12 increases survival in two independent genetic-based mutant SOD1 mouse strains (SOD1G86R and SOD1G93A) by 8 and 10 days, delays the onset of neurological deficits by 16 days, delays the onset of weight loss by 5 days, and preserves spinal cord axons and anterior horn neurons. Immuno-overlay of thin layer chromatography and surface plasmon resonance show that rHIgM12 binds with high affinity to the complex gangliosides GD1a and GT1b. Addition of rHIgM12 to neurons in culture increases α-tubulin tyrosination levels, suggesting an alteration of microtubule dynamics. We previously reported that a single peripheral dose of rHIgM12 preserved neurological function in a murine model of demyelination with axon loss. Because rHIgM12 improves three different models of neurological disease, we propose that the IgM might act late in the cascade of neuronal stress and/or death by a broad mechanism.

  6. Changes in ganglioside content affect the binding of Clostridium perfringens epsilon-toxin to detergent-resistant membranes of Madin-Darby canine kidney cells.

    PubMed

    Shimamoto, Seiko; Tamai, Eiji; Matsushita, Osamu; Minami, Junzaburo; Okabe, Akinobu; Miyata, Shigeru

    2005-01-01

    Epsilon-toxin (ET) of Clostridium perfringens, which causes fatal enterotoxemia in ungulates, was previously shown to bind to and form a heptameric pore within the detergent-resistant membranes (DRMs) of MDCK cells. Depletion of cholesterol has also been shown to decrease the cytotoxicity of ET and its heptamerization. In this study, we investigated the effects of changes in sphingolipids, other DRM components of MDCK cells, on the cells' susceptibility to ET. Treatment with fumonisin B1 and PDMP, inhibitors of sphingolipid and glycosphingolipid syntheses, respectively, increased the susceptibility, while D609, a sphingomyelin synthesis inhibitor, had the opposite effect. The exogenous addition of ganglioside G(M1) dramatically decreased the ET binding, heptamerization and cytotoxicity. These effects were shown not to be due to ET binding to G(M1) or to denaturation of ET. We also found that the ET cytotoxicity towards MDCK cells decreased with an increase in culture time. In accordance with the resistance observed for prolonged cultured cells, G(M3), a major ganglioside component, increased and sialidase treatment increased their susceptibility. These results suggest that membrane-anchored sialic acid of G(M3) within DRMs inhibits ET binding, leading to prevention of the heptamerization of ET and cell death. It is also suggested that sialidase produced by this organism aids the targeting of ET to MDCK cells.

  7. The size of lipid rafts: an atomic force microscopy study of ganglioside GM1 domains in sphingomyelin/DOPC/cholesterol membranes.

    PubMed Central

    Yuan, Chunbo; Furlong, Jennifer; Burgos, Pierre; Johnston, Linda J

    2002-01-01

    Atomic force microscopy has been used to study the distribution of ganglioside GM1 in model membranes composed of ternary lipid mixtures that mimic the composition of lipid rafts. The results demonstrate that addition of 1% GM1 to 1:1:1 sphingomyelin/dioleoylphosphatidylcholine/cholesterol monolayers leads to the formation of small ganglioside-rich microdomains (40-100 nm in size) that are localized preferentially in the more ordered sphingomyelin/cholesterol-rich phase. With 5% GM1 some GM1 microdomains are also detected in the dioleoylphosphatidylcholine-rich phase. A similar preferential localization of GM1 in the ordered phase is observed for bilayers with the same ternary lipid mixture in the upper leaflet. The small GM1-rich domains observed in these experiments are similar to the sizes for lipid rafts in natural membranes but considerably smaller than the ordered bilayer domains that have been shown to be enriched in GM1 in recent fluorescence microscopy studies of lipid bilayers. The combined data from a number of studies of model membranes indicate that lateral organization occurs on a variety of length scales and mimics many of the properties of natural membranes. PMID:11964241

  8. Detection of N-glycolyl GM3 ganglioside in neuroectodermal tumors by immunohistochemistry: an attractive vaccine target for aggressive pediatric cancer.

    PubMed

    Scursoni, Alejandra M; Galluzzo, Laura; Camarero, Sandra; Lopez, Jessica; Lubieniecki, Fabiana; Sampor, Claudia; Segatori, Valeria I; Gabri, Mariano R; Alonso, Daniel F; Chantada, Guillermo; de Dávila, María Teresa G

    2011-01-01

    The N-glycolylated ganglioside NeuGc-GM3 has been described in solid tumors such as breast carcinoma, nonsmall cell lung cancer, and melanoma, but is usually not detected in normal human cells. Our aim was to evaluate the presence of NeuGc-GM3 in pediatric neuroectodermal tumors by immunohistochemistry. Twenty-seven archival cases of neuroblastoma and Ewing sarcoma family of tumors (ESFT) were analyzed. Formalin-fixed, paraffin-embedded tumor samples were cut into 5 μm sections. The monoclonal antibody 14F7, a mouse IgG1 that specifically recognizes NeuGc-GM3, and a peroxidase-labeled polymer conjugated to secondary antibodies were used. Presence of NeuGc-GM3 was evident in 23 of 27 cases (85%), with an average of about 70% of positive tumors cells. Immunoreactivity was moderate to intense in most tumors, showing a diffuse cytoplasmic and membranous staining, although cases of ESFT demonstrated a fine granular cytoplasmic pattern. No significant differences were observed between neuroblastoma with and without NMYC oncogene amplification, suggesting that expression of NeuGc-GM3 is preserved in more aggressive cancers. Until now, the expression of N-glycolylated gangliosides in pediatric neuroectodermal tumors has not been investigated. The present study evidenced the expression of NeuGc-GM3 in a high proportion of neuroectodermal tumors, suggesting its potential utility as a specific target of immunotherapy.

  9. Synthesis of a glioma-related ganglioside, O-Ac GM3 having 3-O-Ac ceramide and its substrate property toward hydrolases.

    PubMed

    Tsuchihashi, K; Daino, T; Akino, T; Gasa, S

    1996-10-01

    An O-acetyl group was selectively introduced into the ceramide moiety at the C-3-O on ganglioside GM3 containing N-acetyl neuraminic acid, the product of which has been previously found in rat glioma tissue as a glioma-associated ganglioside. The introduction of the acetyl residue involved a two-step process involving per O-acetylation of GM3 and saponification with a mild alkaline solution in a bilayer system constituted of water and water-immiscible organic solvent. Of the several solvents studied, 2-pentanol and diethyl ether gave the highest yields (68% and 62%, respectively). The chemical structure of the synthesized 3-O-acetyl GM3 was confirmed by proton nuclear magnetic resonance spectroscopy and fast atom bombardment-mass spectrometry, as well as by comparing the mobilities on thin-layer chromatography of its exoglycosidase-digested products with those of the synthesized, authentic 3-O-acetyl-lactosylceramide and ceramide. Furthermore, the substrate specificities of both 3-O-acetyl GM3 and 3-O-acetyl sphingomyelin toward exo- and endo-hydrolases were examined, revealing that they were hardly cleaved by the endoglycoceramidase and sphingolipid N-deacylase for the 3-O-acetyl GM3 and by sphingomyelinase for 3-O-acetyl sphingomyelin. Thus, the enzymes were found to recognize a free C-3 hydroxyl group on ceramide.

  10. Stage-specific embryonic antigens (SSEA-3 and -4) are epitopes of a unique globo-series ganglioside isolated from human teratocarcinoma cells.

    PubMed Central

    Kannagi, R; Cochran, N A; Ishigami, F; Hakomori, S; Andrews, P W; Knowles, B B; Solter, D

    1983-01-01

    Two monoclonal antibodies (MC631 and MC813-70) raised against 4- to 8-cell stage mouse embryos and a human teratocarcinoma cell line, respectively, detect the stage-specific embryonic antigens, the previously defined SSEA-3 and SSEA-4, described herein. These antibodies were both reactive with a unique globo-series ganglioside with the structure shown below: (formula; see text) The antibodies were found to recognize sequential regions of this ganglioside, i.e., MC813-70 recognizes the terminal 'a' structure whereas antibody MC631 recognizes the internal 'b' structure. Thus, a set of two antibodies defines this unique embryonic antigen. During differentiation of human teratocarcinoma 2102Ep cells, the globo-series glycolipids defined by these antibodies decrease and the lacto-series glycolipids, reacting with the SSEA-1 antibody appear. This antigenic conversion suggests that a shift of glycolipid synthesis from globo-series to lacto-series glycolipids occurs during differentiation of human teratocarcinoma and perhaps of pre-implantation mouse embryos. Images Fig. 1. Fig. 4. Fig. 5. PMID:6141938

  11. GM1 ganglioside activates ERK1/2 and Akt downstream of Trk tyrosine kinase and protects PC12 cells against hydrogen peroxide toxicity.

    PubMed

    Zakharova, Irina O; Sokolova, Tatyana V; Vlasova, Yulia A; Furaev, Victor V; Rychkova, Maria P; Avrova, Natalia F

    2014-11-01

    Ganglioside GM1 at micro- and nanomolar concentrations was shown to increase the viability of pheochromocytoma PC12 cells exposed to hydrogen peroxide and diminish the accumulation of reactive oxygen species and oxidative inactivation of Na(+),K(+)-ATPase, the effects of micromolar GM1 being more pronounced than those of nanomolar GM1. These effects of GM1 were abolished by Trk receptor tyrosine kinase inhibitor and diminished by MEK1/2, phosphoinositide 3-kinase and protein kinase C inhibitors. Hydrogen peroxide activates Trk tyrosine kinase; Akt and ERK1/2 are activated downstream of this protein kinase. GM1 was found to activate Trk receptor tyrosine kinase in PC12 cells. GM1 (100 nM and 10 µM) increased the basal activity of Akt, but did not change Akt activity in cells exposed to hydrogen peroxide. Basal ERK1/2 activity in PC12 cells was increased by GM1 at a concentration of 10 µM, but not at nanomolar concentrations. Activation of ERK1/2 by hydrogen peroxide was enhanced by GM1 at a concentration of 10 µM and to a lesser extent at a concentration of 100 nM. Thus, the protective and metabolic effects of GM1 ganglioside on PC12 cells exposed to hydrogen peroxide appear to depend on the activation of Trk receptor tyrosine kinase and downstream activation of Akt and ERK1/2.

  12. A Monoclonal Antibody to O-Acetyl-GD2 Ganglioside and Not to GD2 Shows Potent Anti-Tumor Activity without Peripheral Nervous System Cross-Reactivity

    PubMed Central

    Cochonneau, Denis; Chaumette, Tanguy; Clemenceau, Béatrice; Leprieur, Stéphanie; Bougras, Gwenola; Supiot, Stéphane; Mussini, Jean-Marie; Barbet, Jacques; Saba, Julie; Paris, François; Aubry, Jacques; Birklé, Stéphane

    2011-01-01

    Background Monoclonal antibodies (mAb) against GD2 ganglioside have been shown to be effective for the treatment of neuroblastoma. Beneficial actions are, however, associated with generalized pain due to the binding of anti- GD2 mAbs to peripheral nerve fibers followed by complement activation. Neuroblastoma cells that express GD2 also express its O-acetyl derivative, O-acetyl- GD2 ganglioside (OAcGD2). Hence, we investigated the distribution of OAcGD2 in human tissues using mAb 8B6 to study the cross-reactivity of mAb 8B6 with human tissues. Methodology/Principal Findings The distribution of OAcGD2 was performed in normal and malignant tissues using an immunoperoxydase technique. Anti-tumor properties of mAb 8B6 were studied in vitro and in vivo in a transplanted tumor model in mice. We found that OAcGD2 is not expressed by peripheral nerve fibers. Furthermore, we demonstrated that mAb 8B6 was very effective in the in vitro and in vivo suppression of the growth of tumor cells. Importantly, mAb 8B6 anti-tumor efficacy was comparable to that of mAb 14G2a specific to GD2. Conclusion/Significance Development of therapeutic antibodies specific to OAcGD2 may offer treatment options with reduced adverse side effects, thereby allowing dose escalation of antibodies. PMID:21966461

  13. The effect of β-sitosterol on the properties of cholesterol/phosphatidylcholine/ganglioside monolayers--the impact of monolayer fluidity.

    PubMed

    Hąc-Wydro, Katarzyna

    2013-10-01

    In this paper the influence of one of phytosterols, namely β-sitosterol on cholesterol (Chol)/phosphatidylcholine (PC)/ganglioside (GM3) monolayers was examined to find the correlation between the properties of model system and the effect of phytocompound. The studied monolayers differed in condensation and fluidity, which were modified by the structure of phosphatidylcholine. It was found that the incorporation of β-sitosterol into cholesterol/phosphatidylcholine/ganglioside films changes their morphology, condensation and interactions between the lipids. The substitution of cholesterol more strongly decreased the condensation and stability of the film containing PC molecules having monounsaturated chains than more densely packed monolayer composed of saturated phosphatidylcholine. However, thorough analysis of data obtained so far suggests that the magnitude of β-sitosterol effect is determined by the composition of the system rather than its fluidity itself. Moreover, the results collected herein correlate well with the findings that phytosterol more strongly inhibits the growth of cancer cells, which at a given proportion of cholesterol to phospholipids in membranes, have more unsaturated fatty acids within phospholipids molecules.

  14. Correlations between cytomegalovirus, Epstein-Barr virus, anti-ganglioside antibodies, electrodiagnostic findings and functional status in Guillain-Barré syndrome

    PubMed Central

    Taheraghdam, Aliakbar; Pourkhanjar, Peyman; Talebi, Mahnaz; Bonyadi, Mohammadreza; Pashapour, Ali; Rikhtegar, Reza

    2014-01-01

    Background Due to underlying autoimmune background of Guillain-Barré syndrome (GBS), the possible role of infectious agents cytomegalovirus (CMV) and Epstein-Barr virus (EBV) and also due to association of anti-ganglioside antibodies with GBS, the present study aimed to investigate the associations between serum anti-ganglioside antibodies (AGA) level, type of infection and electrodiagnostic (ED) findings with the severity and three-month functional outcome of patients with GBS. Methods In a prospective study, 30 patients with GBS were selected and before starting the treatment, baseline serum samples of patients were obtained for measuring the serum AGA including the antibodies against GQ1b, GT1b, GD1a, GD1b, GM1, GM2, GM3 and strains of CMV and EBV. All the patients were precisely examined for ED findings. Functional status of patients on admission and three months after admission were recorded according to the modified Rankin scale (mRS). Results The results of patients’ serum assessment revealed that CMV IgM was positive in one patient (3.3%), CMV IgG in 29 patients (96.7%) and EBV IgG in 27 patients (90%). Anti-GM1 was found in 3 patients (10%) and anti-GM3 was found only in one patient (3.3%). However, no statistical significant association was found between the AGA and strain of the disease and ED findings. Conclusion Despite the coexistence of AGA and serum antibodies against CMV and EBV in some GBS patients, there was not clear association in this regard. However, the AGA was positive in patients who suffered from severe phase of the disease. PMID:24800041

  15. Identification of gangliosides recognized by IgG anti-GalNAc-GD1a antibodies in bovine spinal motor neurons and motor nerves.

    PubMed

    Yoshino, Hiide; Ariga, Toshio; Suzuki, Akemi; Yu, Robert K; Miyatake, Tadashi

    2008-08-28

    The presence of immunoglobulin G (IgG)-type antibodies to the ganglioside, N-acetylgalactosaminyl GD1a (GalNAc-GD1a), is closely associated with the pure motor type of Guillain-Barré syndrome (GBS). In the present study, we isolated disialogangliosides from the motor neurons and motor nerves of bovine spinal cords by DEAE-Sephadex column chromatography. The disialoganglioside fraction contained GD1a, GD2, GD1b, and three gangliosides, designated X1, X2 and X3. Serum from a patient with axonal GBS with IgG anti-GalNAc-GD1a antibody yielded positive immunostaining with X1, X2, and X3. When isolated by preparative thin-layer chromatography (TLC), X1 migrated at the same position as GalNAc-GD1a from Tay-Sachs brain, suggesting that X1 is GalNAc-GD1a containing N-acetylneuraminic acid (NeuAc). TLC of isolated X2 revealed that it migrated between GD1a and GD2. On the other hand, X3 had a migratory rate on TLC between and GD1b and GT1b. Since both X2 and X3 were recognized by IgG anti-GalNAc-GD1a antibody, the results suggest that X2 is a GalNAc-GD1a species containing a mixture containing a NeuAc-and an N-glycolylneuraminic acid (NeuGc) species, and X3 is a GalNAc-GD1a species with two NeuGc. This evidence indicating the specific localization of GalNAc-GD1a and its isomers in spinal motor neurons should be useful in elucidating the pathogenic role of IgG anti-GalNAc-GD1a antibody in pure motor-type GBS.

  16. Relationship between ganglioside expression and anti-cancer effects of the monoclonal antibody against epithelial cell adhesion molecule in colon cancer.

    PubMed

    Kwak, Dong Hoon; Ryu, Jae-Sung; Kim, Chang-Hyun; Ko, Kisung; Ma, Jin Yeul; Hwang, Kyung-A; Choo, Young-Kug

    2011-12-31

    The human colorectal carcinoma-associated GA733 antigen epithelial cell adhesion molecule (EpCAM) was initially described as a cell surface protein selectively expressed in some myeloid cancers. Gangliosides are sialic acid-containing glycosphingolipids involved in inflammation and oncogenesis. We have demonstrated that treatment with anti-EpCAM mAb and RAW264.7 cells significant inhibited the cell growth in SW620 cancer cells, but neither anti-EpCAM mAb nor RAW264.7 cells alone induced cytotoxicity. The relationship between ganglioside expression and the anti- cancer effects of anti-EpCAM mAb and RAW264.7 was investigated by high-performance thin-layer chromatography. The results demonstrated that expression of GM1 and GD1a significantly increased in the ability of anti-EpCAM to inhibit cell growth in SW620 cells. Anti-EpCAM mAb treatment increased the expression of anti-apoptotic proteins such as Bcl-2, but the expression of pro-apoptotic proteins Bax, TNF-α, caspase-3, cleaved caspase-3, and cleaved caspase-8 were unaltered. We observed that anti-EpCAM mAb significantly inhibited the growth of colon tumors, as determined by a decrease in tumor volume and weight. The expression of anti-apoptotic protein was inhibited by treatment with anti-EpCAM mAb, whereas the expression of pro-apoptotic proteins was increased. These results suggest that GD1a and GM1 were closely related to anticancer effects of anti-EpCAM mAb. In light of these results, further clinical investigation should be conducted on anti-EpCAM mAb to determine its possible chemopreventive and/or therapeutic efficacy against human colon cancer.

  17. Enhanced capabilities for imaging gangliosides in murine brain with matrix-assisted laser desorption/ionization and desorption electrospray ionization mass spectrometry coupled to ion mobility separation.

    PubMed

    Škrášková, Karolina; Claude, Emmanuelle; Jones, Emrys A; Towers, Mark; Ellis, Shane R; Heeren, Ron M A

    2016-07-15

    The increased interest in lipidomics calls for improved yet simplified methods of lipid analysis. Over the past two decades, mass spectrometry imaging (MSI) has been established as a powerful technique for the analysis of molecular distribution of a variety of compounds across tissue surfaces. Matrix-assisted laser desorption/ionization (MALDI) MSI is widely used to study the spatial distribution of common lipids. However, a thorough sample preparation and necessity of vacuum for efficient ionization might hamper its use for high-throughput lipid analysis. Desorption electrospray ionization (DESI) is a relatively young MS technique. In DESI, ionization of molecules occurs under ambient conditions, which alleviates sample preparation. Moreover, DESI does not require the application of an external matrix, making the detection of low mass species more feasible due to the lack of chemical matrix background. However, irrespective of the ionization method, the final information obtained during an MSI experiment is very complex and its analysis becomes challenging. It was shown that coupling MSI to ion mobility separation (IMS) simplifies imaging data interpretation. Here we employed DESI and MALDI MSI for a lipidomic analysis of the murine brain using the same IMS-enabled instrument. We report for the first time on the DESI IMS-MSI of multiply sialylated ganglioside species, as well as their acetylated versions, which we detected directly from the murine brain tissue. We show that poly-sialylated gangliosides can be imaged as multiply charged ions using DESI, while they are clearly separated from the rest of the lipid classes based on their charge state using ion mobility. This represents a major improvement in MSI of intact fragile lipid species. We additionally show that complementary lipid information is reached under particular conditions when DESI is compared to MALDI MSI.

  18. Cholesterol accelerates the binding of Alzheimer's β-amyloid peptide to ganglioside GM1 through a universal hydrogen-bond-dependent sterol tuning of glycolipid conformation

    PubMed Central

    Fantini, Jacques; Yahi, Nouara; Garmy, Nicolas

    2013-01-01

    Age-related alterations of membrane lipids in brain cell membranes together with high blood cholesterol are considered as major risk factors for Alzheimer's disease. Yet the molecular mechanisms by which these factors increase Alzheimer's risk are mostly unknown. In lipid raft domains of the plasma membrane, neurotoxic Alzheimer's beta-amyloid (Abeta) peptides interact with both cholesterol and ganglioside GM1. Recent data also suggested that cholesterol could stimulate the binding of Abeta to GM1 through conformational modulation of the ganglioside headgroup. Here we used a combination of physicochemical and molecular modeling approaches to decipher the mechanisms of cholesterol-assisted binding of Abeta to GM1. With the aim of decoupling the effect of cholesterol on GM1 from direct Abeta-cholesterol interactions, we designed a minimal peptide (Abeta5-16) containing the GM1-binding domain but lacking the amino acid residues involved in cholesterol recognition. Using the Langmuir technique, we showed that cholesterol (but not phosphatidylcholine or sphingomyelin) significantly accelerates the interaction of Abeta5-16 with GM1. Molecular dynamics simulations suggested that Abeta5-16 interacts with a cholesterol-stabilized dimer of GM1. The main structural effect of cholesterol is to establish a hydrogen-bond between its own OH group and the glycosidic-bond linking ceramide to the glycone part of GM1, thereby inducing a tilt in the glycolipid headgroup. This fine conformational tuning stabilizes the active conformation of the GM1 dimer whose headgroups, oriented in two opposite directions, form a chalice-shaped receptacle for Abeta. These data give new mechanistic insights into the stimulatory effect of cholesterol on Abeta/GM1 interactions. They also support the emerging concept that cholesterol is a universal modulator of protein-glycolipid interactions in the broader context of membrane recognition processes. PMID:23772214

  19. In cellulo examination of a beta-alpha hybrid construct of beta-hexosaminidase A subunits, reported to interact with the GM2 activator protein and hydrolyze GM2 ganglioside.

    PubMed

    Sinici, Incilay; Yonekawa, Sayuri; Tkachyova, Ilona; Gray, Steven J; Samulski, R Jude; Wakarchuk, Warren; Mark, Brian L; Mahuran, Don J

    2013-01-01

    The hydrolysis in lysosomes of GM2 ganglioside to GM3 ganglioside requires the correct synthesis, intracellular assembly and transport of three separate gene products; i.e., the alpha and beta subunits of heterodimeric beta-hexosaminidase A, E.C. # 3.2.1.52 (encoded by the HEXA and HEXB genes, respectively), and the GM2-activator protein (GM2AP, encoded by the GM2A gene). Mutations in any one of these genes can result in one of three neurodegenerative diseases collectively known as GM2 gangliosidosis (HEXA, Tay-Sachs disease, MIM # 272800; HEXB, Sandhoff disease, MIM # 268800; and GM2A, AB-variant form, MIM # 272750). Elements of both of the hexosaminidase A subunits are needed to productively interact with the GM2 ganglioside-GM2AP complex in the lysosome. Some of these elements have been predicted from the crystal structures of hexosaminidase and the activator. Recently a hybrid of the two subunits has been constructed and reported to be capable of forming homodimers that can perform this reaction in vivo, which could greatly simplify vector-mediated gene transfer approaches for Tay-Sachs or Sandhoff diseases. A cDNA encoding a hybrid hexosaminidase subunit capable of dimerizing and hydrolyzing GM2 ganglioside could be incorporated into a single vector, whereas packaging both subunits of hexosaminidase A into vectors, such as adeno-associated virus, would be impractical due to size constraints. In this report we examine the previously published hybrid construct (H1) and a new more extensive hybrid (H2), with our documented in cellulo (live cell- based) assay utilizing a fluorescent GM2 ganglioside derivative. Unfortunately when Tay-Sachs cells were transfected with either the H1 or H2 hybrid construct and then were fed the GM2 derivative, no significant increase in its turnover was detected. In vitro assays with the isolated H1 or H2 homodimers confirmed that neither was capable of human GM2AP-dependent hydrolysis of GM2 ganglioside. PMID:23483939

  20. Measurements of defect structures by positron annihilation lifetime spectroscopy of the tellurite glass TeO2-P2O5-ZnO-LiNbO3 doped with ions of rare earth elements: Er3+, Nd3+ and Gd3+

    NASA Astrophysics Data System (ADS)

    Golis, E.; Yousef, El. S.; Reben, M.; Kotynia, K.; Filipecki, J.

    2015-12-01

    The objective of the study was the structural analysis of the TeO2-P2O5-ZnO-LiNbO3 tellurite glasses doped with ions of the rare-earth elements: Er3+, Nd3+ and Gd3+ based on the PALS (Positron Annihilation Lifetime Spectroscopy) method of measuring positron lifetimes. Values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects, such as vacancies, mono-vacancies, dislocations or pores, the sizes of which range from a few angstroms to a few dozen nanometres. Experimental positron lifetime spectrum revealed existence of two positron lifetime components τ1 and τ2. Their interpretation was based on two-state positron trapping model where the physical parameters are the annihilation velocity and positron trapping rate.

  1. Thapsigargin activates univalent- and bivalent-cation entry in human neutrophils by a SK&F I3 96365- and Gd3+-sensitive pathway and is a partial secretagogue: involvement of pertussis-toxin-sensitive G-proteins and protein phosphatases 1/2A and 2B in the signal-transduction pathway.

    PubMed Central

    Wenzel-Seifert, K; Krautwurst, D; Musgrave, I; Seifert, R

    1996-01-01

    The Ca2+-ATPase inhibitor thapsigargin (TG) activates bivalent-cation early in human neutrophils via depletion of intracellular Ca2+ stores bu little is known about the underlying mechanism and the functional role of TG-induced cation entry. We studied the effects of TG on univalent- and bivalent cation entry, lysozyme release and superoxide-anion (O2-) formation in human neutrophils. TG, like the chemotactic peptide, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), stimulated entry of Ca2+, Mn2+, Ba2+, Sr2+ and Na+ in a 1-¿beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl¿-1H-imidazole hydrochloride (SK&F 96365)- and Gd3+-sensitive manner. The inhibitors of protein phosphates 1/2A, calyculin A and okadaic acid, diminished TG-induced cation influxes, whereas the inhibitors of protein phosphatase 2B, cyclosporin A and FK-506, were potentiators. Pertussis toxin (PTX) partially inhibited the effects of TG on Ca2+ and Mn2+ entry. TG and fMLP activated inward currents with a linear current-voltage relationship and a reversal potential at about 0 mV. TG activated lysozyme release and potentiated fMLP-induced O2- formation. TG-induced lysozyme release was inhibited by SK&F 96365, PTX and the removal of extracellular Ca2+ or Na+. Our data show that TG activates a non-selective and SK&F 96365- and Gd3+-sensitive cation entry pathway and is a partial secretagogue. TG-stimulated cation entry involves PTX-sensitive G-proteins and protein phosphatases, with protein phosphatases 1/2A and 2B playing opposite roles. PMID:8670085

  2. Intracranial V. cholerae sialidase protects against excitotoxic neurodegeneration.

    PubMed

    Dhanushkodi, Anandh; McDonald, Michael P

    2011-01-01

    Converging evidence shows that GD3 ganglioside is a critical effector in a number of apoptotic pathways, and GM1 ganglioside has neuroprotective and noötropic properties. Targeted deletion of GD3 synthase (GD3S) eliminates GD3 and increases GM1 levels. Primary neurons from GD3S-/- mice are resistant to neurotoxicity induced by amyloid-β or hyperhomocysteinemia, and when GD3S is eliminated in the APP/PSEN1 double-transgenic model of Alzheimer's disease the plaque-associated oxidative stress and inflammatory response are absent. To date, no small-molecule inhibitor of GD3S exists. In the present study we used sialidase from Vibrio cholerae (VCS) to produce a brain ganglioside profile that approximates that of GD3S deletion. VCS hydrolyzes GD1a and complex b-series gangliosides to GM1, and the apoptogenic GD3 is degraded. VCS was infused by osmotic minipump into the dorsal third ventricle in mice over a 4-week period. Sensorimotor behaviors, anxiety, and cognition were unaffected in VCS-treated mice. To determine whether VCS was neuroprotective in vivo, we injected kainic acid on the 25th day of infusion to induce status epilepticus. Kainic acid induced a robust lesion of the CA3 hippocampal subfield in aCSF-treated controls. In contrast, all hippocampal regions in VCS-treated mice were largely intact. VCS did not protect against seizures. These results demonstrate that strategic degradation of complex gangliosides and GD3 can be used to achieve neuroprotection without adversely affecting behavior. PMID:22195039

  3. Mutations in the ganglioside-induced differentiation-associated protein-1 (GDAP1) gene in intermediate type autosomal recessive Charcot-Marie-Tooth neuropathy.

    PubMed

    Senderek, Jan; Bergmann, Carsten; Ramaekers, Vincent T; Nelis, Eva; Bernert, Günther; Makowski, Astrid; Züchner, Stephan; De Jonghe, Peter; Rudnik-Schöneborn, Sabine; Zerres, Klaus; Schröder, J Michael

    2003-03-01

    Mutations in the gene for the ganglioside-induced differentiation-associated protein-1 (GDAP1) on 8q21 recently were reported to cause autosomal recessive Charcot-Marie-Tooth (CMT) sensorimotor neuropathy. Neurophysiology and nerve pathology were heterogeneous in these cases: a subset of GDAP1 mutations was associated with peripheral nerve demyelination, whereas others resulted in axonal degeneration. In this study, we identified two novel mutations disrupting the GDAP1 reading frame. Homozygosity for a single base pair insertion in exon 3 (c.349_350insT) was observed in affected children from a Turkish inbred pedigree. The other novel allele detected in a German patient was a homozygous mutation of the intron 4 donor splice site (c.579 + 1G>A). Patients with GDAP1 mutations displayed severe, early childhood-onset CMT neuropathy with prominent pes equinovarus deformity and impairment of hand muscles. Nerve conduction velocities were between 25 and 35 m/s and peripheral nerve pathology showed axonal as well as demyelinating changes. These findings fitted the definition of intermediate type CMT and further support the view that GDAP1 is vital for both, axonal integrity and Schwann cell properties.

  4. GM1 ganglioside reduces the motor incoordination and loss of righting reflex caused by acute ethanol in C57BL/6J mice

    SciTech Connect

    Wallis, C.; Rezazadeh, S.M.; Forster, M.J.; Lal, H. )

    1992-02-26

    Ethanol produces its intoxicating effects by modifying neuronal membranes. Gangliosides stabilize neuronal membranes and promote their recovery from a variety of insults. In this experiment, the efficacy of GM1(i.p.) to reverse ethanol intoxication was evaluated in male mice trained to run on a constantly accelerating rotorod. When mice were tested 15-min following saline or ethanol GM1 pre-treatment reduced rotorod performance by 15% but was ineffective in modifying the ethanol-impaired performance. However, when mice were tested at 15, 35, 55, 75, and 95 min intervals following ethanol, GM1 pre-treatments dose-dependently reduced the efficacy and duration of ethanol in producing motor incoordination. Further, GM1 given prior to ethanol significantly prolonged the time to onset of the loss of righting reflex from 1.4 to 1.9 min, and reduced the duration of the righting-reflex loss from 94 to 77 min. This GM1 effect was seen at 24 h, but not at 48 or 72 h after its administration. The blood ethanol concentration at awakening was significantly higher in 24h GM1-treated animals than in controls suggesting that the GM1 effect was not due to an alteration in ethanol clearance. These findings support the hypothesis that GM1 promotes recovery from ethanol intoxication via a neuroprotective mechanism.

  5. Targeting GD2 ganglioside and aurora A kinase as a dual strategy leading to cell death in cultures of human neuroblastoma cells.

    PubMed

    Horwacik, Irena; Durbas, Małgorzata; Boratyn, Elżbieta; Węgrzyn, Paulina; Rokita, Hanna

    2013-12-01

    The mechanism of the inhibitory effect of anti-GD2 ganglioside (GD2) 14G2a mouse monoclonal antibody (mAb) on human neuroblastoma cells survival was studied in vitro. It was recently shown in IMR-32 cells that death induced by this antibody exhibited several characteristics typical of apoptosis. In this study we used cytotoxixity assays, qRT-PCR and immunoblotting to evaluate the response of several human neuroblastoma cell lines to the anti-GD2 14G2a mAb. We showed that the mAb decreases all three aurora kinases expression and phosphorylation in IMR-32 and LA-N-1 cells. Most importantly, we show, that MK-5108 specific aurora A kinase inhibitor decreases neuroblastoma cell survival, and when used in combination with the mAb, significantly potentiates cytotoxicity against IMR-32, CHP-134, and LA-N-5 neuroblastoma cells in vitro. It was shown that downregulation of aurora A kinase by the therapeutic antibody is associated with decreased levels of MYCN protein in cytoplasm, and induced expression of PHLDA1 and P53 proteins. PMID:23962557

  6. Ligands Binding to Cell Surface Ganglioside GD2 Cause Src-Dependent Activation of N-Methyl-D-Aspartate Receptor Signaling and Changes in Cellular Morphology

    PubMed Central

    Gagnon, Martin; Saragovi, H. Uri

    2015-01-01

    Ganglioside GD2 is a plasma membrane glycosphinogolipid. In healthy adults it is expressed at low levels, but it is over-expressed in many cancers. For cancer therapy, GD2 is targeted with anti-GD2 monoclonal antibodies (mAbs), and one adverse side effect is severe visceral pain. Pain is not neuropathic, cannot be blocked with morphine, and stops on discontinuation of mAb therapy. Here, we provide evidence that ligand binding to cell surface GD2 induces rapid and transient activation of Src-family kinases, followed by Src-dependent phosphorylation of NMDA-receptor NR2B subunits selectively, activation of Ca++ fluxes, production of cAMP, and changes in cellular morphology. These GD2-ligand activated signals differ in kinetics and in pharmacology from activation of the same signals in the same cells by BDNF, the growth factor agonist of the TrkB receptor, suggesting biological specificity. Hence, cell surface GD2 regulates pathways that can be associated with neoplasia and with morphine-intractable pain; and this can explain why expression of GD2 correlates with these two pathologies. PMID:26252487

  7. Complexing mechanism of the lanthanide cations Eu3+, Gd3+, and Tb3+ with 1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane (dota)-characterization of three successive complexing phases: study of the thermodynamic and structural properties of the complexes by potentiometry, luminescence spectroscopy, and EXAFS.

    PubMed

    Moreau, Juliette; Guillon, Emmanuel; Pierrard, Jean-Claude; Rimbault, Jean; Port, Marc; Aplincourt, Michel

    2004-10-11

    Complexation of the lanthanides Eu3+, Gd3+, and Tb3+ with 1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane (dota) has been studied in solution by using potentiometry, luminescence spectrometry, and EXAFS. Three series of successive complexes were characterized by at least two of these methods: the immediate [LnHn(dota)](n-1)+** and intermediate [LnHn(dota)](n-1)+* complexes with 0

  8. Development of a novel therapy for Lipo-oligosaccharide-induced experimental neuritis: use of peptide glycomimics

    PubMed Central

    Usuki, Seigo; Taguchi, Kyoji; Gu, Yi-Hua; Thompson, Stuart A.; Yu, Robert K.

    2010-01-01

    Recent etiological studies have revealed that molecular mimicry between the lipo-oligosaccharide (LOS) component of Campylobacter jejuni and gangliosides of peripheral nervous system plays an important role in the pathogenesis of Guillain-Barré syndrome (GBS). Previously, we demonstrated GD3 ganglioside molecular mimicry in a model of GBS in Lewis rats by sensitization with GD3-like LOS (LOSGD3) from C. jejuni. Since the neuropathophysiological consequences were due largely to the anti-GD3-like antibodies, we subsequently focused our effort upon eliminating the pathogenic antibodies using several strategies to mimic GD3 in this model. Here, we have validated this strategy by the use of peptide glycomimics based on epitopic mimicry between carbohydrates and peptides. We treated rats by i.p. administration of phage-displayed GD3-like peptides. One GD3-like peptide (PGD3-4; RHAYRSMAEWGFLYS) induced in treated rats a remarkable restoration of motor nerve functions, as evidenced by improved histopathology, rotarod performance, and motor nerve conduction velocity. PGD3-4 effectively decreased the titer of anti-GD3/anti-LOSGD3 antibodies and ameliorated peripheral nerve dysfunction in the sera of treated rats. The data suggest that peptide glycomimics of ganglioside may be potential powerful reagents for therapeutic intervention in GBS by neutralizing specific pathogenic anti-ganglioside antibodies. PMID:20132479

  9. Binding Cooperativity Matters: A GM1-Like Ganglioside-Cholera Toxin B Subunit Binding Study Using a Nanocube-Based Lipid Bilayer Array

    PubMed Central

    Weatherston, Joshua D.

    2016-01-01

    Protein-glycan recognition is often mediated by multivalent binding. These multivalent bindings can be further complicated by cooperative interactions between glycans and individual glycan binding subunits. Here we have demonstrated a nanocube-based lipid bilayer array capable of quantitatively elucidating binding dissociation constants, maximum binding capacity, and binding cooperativity in a high-throughput format. Taking cholera toxin B subunit (CTB) as a model cooperativity system, we studied both GM1 and GM1-like gangliosides binding to CTB. We confirmed the previously observed CTB-GM1 positive cooperativity. Surprisingly, we demonstrated fucosyl-GM1 has approximately 7 times higher CTB binding capacity than GM1. In order to explain this phenomenon, we hypothesized that the reduced binding cooperativity of fucosyl-GM1 caused the increased binding capacity. This was unintuitive, as GM1 exhibited higher binding avidity (16 times lower dissociation constant). We confirmed the hypothesis using a theoretical stepwise binding model of CTB. Moreover, by taking a mixture of fucosyl-GM1 and GM2, we observed the mild binding avidity fucosyl-GM1 activated GM2 receptors enhancing the binding capacity of the lipid bilayer surface. This was unexpected as GM2 receptors have negligible binding avidity in pure GM2 bilayers. These unexpected discoveries demonstrate the importance of binding cooperativity in multivalent binding mechanisms. Thus, quantitative analysis of multivalent protein-glycan interactions in heterogeneous glycan systems is of critical importance. Our user-friendly, robust, and high-throughput nanocube-based lipid bilayer array offers an attractive method for dissecting these complex mechanisms. PMID:27070150

  10. Alteration of Electrostatic Surface Potential Enhances Affinity and Tumor Killing Properties of Anti-ganglioside GD2 Monoclonal Antibody hu3F8.

    PubMed

    Zhao, Qi; Ahmed, Mahiuddin; Guo, Hong-fen; Cheung, Irene Y; Cheung, Nai-Kong V

    2015-05-22

    Ganglioside GD2 is highly expressed on neuroectodermal tumors and an attractive therapeutic target for antibodies that have already shown some clinical efficacy. To further improve the current antibodies, which have modest affinity, we sought to improve affinity by using a combined method of random mutagenesis and in silico assisted design to affinity-mature the anti-GD2 monoclonal antibody hu3F8. Using yeast display, mutants in the Fv with enhanced binding over the parental clone were FACS-sorted and cloned. In silico modeling identified the minimal key interacting residues involved in the important charged interactions with the sialic acid groups of GD2. Two mutations, D32H (L-CDR1) and E1K (L-FR1) altered the electrostatic surface potential of the antigen binding site, allowing for an increase in positive charge to enhance the interaction with the negatively charged GD2-pentasaccharide headgroup. Purified scFv and IgG mutant forms were then tested for antigen specificity by ELISA, for tissue specificity by immunohistochemistry, for affinity by BIACORE, for antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-mediated cytotoxicity in vitro, and for anti-tumor efficacy in xenografted humanized mice. The nearly 7-fold improvement in affinity of hu3F8 with a single D32H (L-CDR1) mutation translated into a ∼12-fold improvement in NK92MI-transfected CD16-mediated ADCC, a 6-fold improvement in CD32-mediated ADCC, and a 2.5-fold improvement in complement-mediated cytotoxicity while maintaining restricted normal tissue cross-reactivity and achieving substantial improvement in tumor ablation in vivo. Despite increasing GD2 affinity, the double mutation D32H (L-CDR1) and E1K (L-FR1) did not further improve anti-tumor efficacy.

  11. Immunization with a mimotope of GD2 ganglioside induces CD8+ T cells that recognize cell adhesion molecules on tumor cells.

    PubMed

    Wierzbicki, Andrzej; Gil, Margaret; Ciesielski, Michael; Fenstermaker, Robert A; Kaneko, Yutaro; Rokita, Hanna; Lau, Joseph T; Kozbor, Danuta

    2008-11-01

    The GD2 ganglioside expressed on neuroectodermal tumor cells has been used as a target for passive and active immunotherapy in patients with malignant melanoma and neuroblastoma. We have reported that immunization of mice with a 47-LDA mimotope of GD2, isolated from a phage display peptide library with anti-GD2 mAb 14G2a, induces MHC class I-restricted CD8(+) T cell responses to syngeneic neuroblastoma tumor cells. The cytotoxic activity of the vaccine-induced CTLs was independent of GD2 expression, suggesting recognition of a novel tumor-associated Ag cross-reacting with 47-LDA. Glycan microarray and immunoblotting studies using 14G2a mAb demonstrated that this Ab is highly specific for the entire carbohydrate motif of GD2 but also cross-reacts with a 105 kDa glycoprotein expressed by GD2(+) and GD2(-) neuroblastoma and melanoma cells. Functional studies of tumor cells grown in three-dimensional collagen cultures with 14G2a mAb showed decreases in matrix metalloproteinase-2 activation, a process regulated by the 105 kDa-activated leukocyte cell adhesion molecule (ALCAM/CD166). A recombinant CD166 glycoprotein was shown to be recognized by 14G2a Ab and inhibition of CD166 expression by RNA interference ablated the cell sensitivity to lysis by 47-LDA-induced CD8(+) T cells in vitro and in vivo. The binding of 14G2a to CD166 was not disruptable by a variety of exo- and endo-glycosidases, implying recognition of a non-glycan epitope on CD166. These results suggest that the vaccine-induced CTLs recognize a 47-LDA cross-reactive epitope expressed by CD166, and reveal a novel mechanism of induction of potent tumor-specific cellular responses by mimotopes of tumor-associated carbohydrate Ags.

  12. Alteration of Electrostatic Surface Potential Enhances Affinity and Tumor Killing Properties of Anti-ganglioside GD2 Monoclonal Antibody hu3F8.

    PubMed

    Zhao, Qi; Ahmed, Mahiuddin; Guo, Hong-fen; Cheung, Irene Y; Cheung, Nai-Kong V

    2015-05-22

    Ganglioside GD2 is highly expressed on neuroectodermal tumors and an attractive therapeutic target for antibodies that have already shown some clinical efficacy. To further improve the current antibodies, which have modest affinity, we sought to improve affinity by using a combined method of random mutagenesis and in silico assisted design to affinity-mature the anti-GD2 monoclonal antibody hu3F8. Using yeast display, mutants in the Fv with enhanced binding over the parental clone were FACS-sorted and cloned. In silico modeling identified the minimal key interacting residues involved in the important charged interactions with the sialic acid groups of GD2. Two mutations, D32H (L-CDR1) and E1K (L-FR1) altered the electrostatic surface potential of the antigen binding site, allowing for an increase in positive charge to enhance the interaction with the negatively charged GD2-pentasaccharide headgroup. Purified scFv and IgG mutant forms were then tested for antigen specificity by ELISA, for tissue specificity by immunohistochemistry, for affinity by BIACORE, for antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-mediated cytotoxicity in vitro, and for anti-tumor efficacy in xenografted humanized mice. The nearly 7-fold improvement in affinity of hu3F8 with a single D32H (L-CDR1) mutation translated into a ∼12-fold improvement in NK92MI-transfected CD16-mediated ADCC, a 6-fold improvement in CD32-mediated ADCC, and a 2.5-fold improvement in complement-mediated cytotoxicity while maintaining restricted normal tissue cross-reactivity and achieving substantial improvement in tumor ablation in vivo. Despite increasing GD2 affinity, the double mutation D32H (L-CDR1) and E1K (L-FR1) did not further improve anti-tumor efficacy. PMID:25851904

  13. Binding Cooperativity Matters: A GM1-Like Ganglioside-Cholera Toxin B Subunit Binding Study Using a Nanocube-Based Lipid Bilayer Array.

    PubMed

    Worstell, Nolan C; Krishnan, Pratik; Weatherston, Joshua D; Wu, Hung-Jen

    2016-01-01

    Protein-glycan recognition is often mediated by multivalent binding. These multivalent bindings can be further complicated by cooperative interactions between glycans and individual glycan binding subunits. Here we have demonstrated a nanocube-based lipid bilayer array capable of quantitatively elucidating binding dissociation constants, maximum binding capacity, and binding cooperativity in a high-throughput format. Taking cholera toxin B subunit (CTB) as a model cooperativity system, we studied both GM1 and GM1-like gangliosides binding to CTB. We confirmed the previously observed CTB-GM1 positive cooperativity. Surprisingly, we demonstrated fucosyl-GM1 has approximately 7 times higher CTB binding capacity than GM1. In order to explain this phenomenon, we hypothesized that the reduced binding cooperativity of fucosyl-GM1 caused the increased binding capacity. This was unintuitive, as GM1 exhibited higher binding avidity (16 times lower dissociation constant). We confirmed the hypothesis using a theoretical stepwise binding model of CTB. Moreover, by taking a mixture of fucosyl-GM1 and GM2, we observed the mild binding avidity fucosyl-GM1 activated GM2 receptors enhancing the binding capacity of the lipid bilayer surface. This was unexpected as GM2 receptors have negligible binding avidity in pure GM2 bilayers. These unexpected discoveries demonstrate the importance of binding cooperativity in multivalent binding mechanisms. Thus, quantitative analysis of multivalent protein-glycan interactions in heterogeneous glycan systems is of critical importance. Our user-friendly, robust, and high-throughput nanocube-based lipid bilayer array offers an attractive method for dissecting these complex mechanisms. PMID:27070150

  14. Immunization with a mimotope of GD2 ganglioside induces CD8+ T cells that recognize cell adhesion molecules on tumor cells.

    PubMed

    Wierzbicki, Andrzej; Gil, Margaret; Ciesielski, Michael; Fenstermaker, Robert A; Kaneko, Yutaro; Rokita, Hanna; Lau, Joseph T; Kozbor, Danuta

    2008-11-01

    The GD2 ganglioside expressed on neuroectodermal tumor cells has been used as a target for passive and active immunotherapy in patients with malignant melanoma and neuroblastoma. We have reported that immunization of mice with a 47-LDA mimotope of GD2, isolated from a phage display peptide library with anti-GD2 mAb 14G2a, induces MHC class I-restricted CD8(+) T cell responses to syngeneic neuroblastoma tumor cells. The cytotoxic activity of the vaccine-induced CTLs was independent of GD2 expression, suggesting recognition of a novel tumor-associated Ag cross-reacting with 47-LDA. Glycan microarray and immunoblotting studies using 14G2a mAb demonstrated that this Ab is highly specific for the entire carbohydrate motif of GD2 but also cross-reacts with a 105 kDa glycoprotein expressed by GD2(+) and GD2(-) neuroblastoma and melanoma cells. Functional studies of tumor cells grown in three-dimensional collagen cultures with 14G2a mAb showed decreases in matrix metalloproteinase-2 activation, a process regulated by the 105 kDa-activated leukocyte cell adhesion molecule (ALCAM/CD166). A recombinant CD166 glycoprotein was shown to be recognized by 14G2a Ab and inhibition of CD166 expression by RNA interference ablated the cell sensitivity to lysis by 47-LDA-induced CD8(+) T cells in vitro and in vivo. The binding of 14G2a to CD166 was not disruptable by a variety of exo- and endo-glycosidases, implying recognition of a non-glycan epitope on CD166. These results suggest that the vaccine-induced CTLs recognize a 47-LDA cross-reactive epitope expressed by CD166, and reveal a novel mechanism of induction of potent tumor-specific cellular responses by mimotopes of tumor-associated carbohydrate Ags. PMID:18941255

  15. Immunization with a Mimotope of GD2 Ganglioside Induces CD8+ T Cells That Recognize Cell Adhesion Molecules on Tumor Cells1

    PubMed Central

    Wierzbicki, Andrzej; Gil, Margaret; Ciesielski, Michael; Fenstermaker, Robert A.; Kaneko, Yutaro; Rokita, Hanna; Lau, Joseph T.; Kozbor, Danuta

    2009-01-01

    The GD2 ganglioside expressed on neuroectodermal tumor cells has been used as a target for passive and active immunotherapy in patients with malignant melanoma and neuroblastoma. We have reported that immunization of mice with a 47-LDA mimotope of GD2, isolated from a phage display peptide library with anti-GD2 mAb 14G2a, induces MHC class I-restricted CD8+ T cell responses to syngeneic neuroblastoma tumor cells. The cytotoxic activity of the vaccine-induced CTLs was independent of GD2 expression, suggesting recognition of a novel tumor-associated Ag cross-reacting with 47-LDA. Glycan microarray and immunoblotting studies using 14G2a mAb demonstrated that this Ab is highly specific for the entire carbohydrate motif of GD2 but also cross-reacts with a 105 kDa glycoprotein expressed by GD2+ and GD2− neuroblastoma and melanoma cells. Functional studies of tumor cells grown in three-dimensional collagen cultures with 14G2a mAb showed decreases in matrix metalloproteinase-2 activation, a process regulated by the 105 kDa-activated leukocyte cell adhesion molecule (ALCAM/CD166). A recombinant CD166 glycoprotein was shown to be recognized by 14G2a Ab and inhibition of CD166 expression by RNA interference ablated the cell sensitivity to lysis by 47-LDA-induced CD8+ T cells in vitro and in vivo. The binding of 14G2a to CD166 was not disruptable by a variety of exo- and endo-glycosidases, implying recognition of a non-glycan epitope on CD166. These results suggest that the vaccine-induced CTLs recognize a 47-LDA cross-reactive epitope expressed by CD166, and reveal a novel mechanism of induction of potent tumor-specific cellular responses by mimotopes of tumor-associated carbohydrate Ags. PMID:18941255

  16. Alteration of Electrostatic Surface Potential Enhances Affinity and Tumor Killing Properties of Anti-ganglioside GD2 Monoclonal Antibody hu3F8*

    PubMed Central

    Zhao, Qi; Ahmed, Mahiuddin; Guo, Hong-fen; Cheung, Irene Y.; Cheung, Nai-Kong V.

    2015-01-01

    Ganglioside GD2 is highly expressed on neuroectodermal tumors and an attractive therapeutic target for antibodies that have already shown some clinical efficacy. To further improve the current antibodies, which have modest affinity, we sought to improve affinity by using a combined method of random mutagenesis and in silico assisted design to affinity-mature the anti-GD2 monoclonal antibody hu3F8. Using yeast display, mutants in the Fv with enhanced binding over the parental clone were FACS-sorted and cloned. In silico modeling identified the minimal key interacting residues involved in the important charged interactions with the sialic acid groups of GD2. Two mutations, D32H (L-CDR1) and E1K (L-FR1) altered the electrostatic surface potential of the antigen binding site, allowing for an increase in positive charge to enhance the interaction with the negatively charged GD2-pentasaccharide headgroup. Purified scFv and IgG mutant forms were then tested for antigen specificity by ELISA, for tissue specificity by immunohistochemistry, for affinity by BIACORE, for antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-mediated cytotoxicity in vitro, and for anti-tumor efficacy in xenografted humanized mice. The nearly 7-fold improvement in affinity of hu3F8 with a single D32H (L-CDR1) mutation translated into a ∼12-fold improvement in NK92MI-transfected CD16-mediated ADCC, a 6-fold improvement in CD32-mediated ADCC, and a 2.5-fold improvement in complement-mediated cytotoxicity while maintaining restricted normal tissue cross-reactivity and achieving substantial improvement in tumor ablation in vivo. Despite increasing GD2 affinity, the double mutation D32H (L-CDR1) and E1K (L-FR1) did not further improve anti-tumor efficacy. PMID:25851904

  17. Pharmacokinetics of anti-ganglioside GD2 mAb 14G2a in a phase I trial in pediatric cancer patients.

    PubMed

    Uttenreuther-Fischer, M M; Huang, C S; Reisfeld, R A; Yu, A L

    1995-07-01

    A phase I trial of a murine anti-ganglioside (GD2) monoclonal antibody (mAb) 14G2a was conducted in 14 neuroblastoma patients and 1 osteosarcoma patient to assess its safety, toxicity and pharmacokinetics in pediatric patients. The pharmacokinetics of mAb 14G2a were biphasic with a t alpha 1/2 of 2.8 +/- 2.8 h and a t beta 1/2 of 18.3 +/- 11.8 h. In general, t beta 1/2 was dose-dependent with a level of significance of P = 0.036, and it reached a plateau at doses of 250 mg/m2 or more. Overall the peak serum levels were dose-dependent at P < 0.001. However, they demonstrated an abrupt increase between doses of 100 mg/m2 and 250 mg/m2. The latter two suggest a saturable mechanism for mAb elimination. In addition, peak serum concentrations were observed earlier at higher mAb doses, which indicates the achievement of a steady state. The t beta 1/2 of mAb 14G2a in children appears to be shorter than in adults. Furthermore, 2 patients demonstrated a considerable decrease in t beta 1/2 following retreatment with 14G2a. This was paralleled by high human anti-(mouse Ig) antibody levels. This study represents the first comprehensive analysis of murine mAb pharmacokinetics in children and will be useful in the future design of mAb therapy. PMID:7641217

  18. Anti-proliferative and pro-apoptotic activity of GD2 ganglioside-specific monoclonal antibody 3F8 in human melanoma cells

    PubMed Central

    Tsao, Chun-Yen; Sabbatino, Francesco; Cheung, Nai-Kong V; Hsu, Jeff Chi-feng; Villani, Vincenzo; Wang, Xinhui; Ferrone, Soldano

    2015-01-01

    The beneficial clinical effects of immunotherapy with GD2-specific monoclonal antibodies (mAbs) in melanoma and neuroblastoma patients have stimulated interest in characterizing the mechanisms underlying their antitumor effects. Previous studies have shown that GD2-specific mAbs mediate complement- and cell-dependent cytotoxicity and induce caspase-dependent apoptosis of tumor cells. In this study, we showed that GD2-specific mAb 3F8, which is undergoing clinical evaluation, inhibited the in vitro growth and induced apoptosis of melanoma cells. This effect was dose- and time-dependent, mediated by the interaction of mAb 3F8 combining site with GD2 ganglioside, associated with GD2 expression level on the cell surface, mAb internalization and increase of GD2 containing endosomes triggered by mAb 3F8. The induction of apoptosis by mAb 3F8 was mediated by caspase 3-, 7-, and 8-dependent pathways, downregulation of the anti-apoptotic molecules survivin and cytochrome c, and caspase 9 independent-AIF release from mitochondria. In addition, analyses of signaling pathway components demonstrated that mAb 3F8 strongly inhibited AKT and FAK activation and increased cleaved PARP expression. These results indicated that multiple mechanisms played a role in the antitumor activity of mAb 3F8 in melanoma cells. This information should provide a mechanistic basis for the optimization of the rational design of immunotherapeutic strategies in the mAb-based treatment of GD2 positive tumors. PMID:26405581

  19. GD2 ganglioside specific antibody treatment downregulates PI3K/Akt/mTOR signaling network in human neuroblastoma cell lines.

    PubMed

    Durbas, Małgorzata; Horwacik, Irena; Boratyn, Elżbieta; Kamycka, Elżbieta; Rokita, Hanna

    2015-09-01

    Mechanisms leading to inhibitory effects of an anti-GD2 ganglioside (GD2) 14G2a mouse monoclonal antibody (mAb) and PI3K/Akt/mTOR pathway inhibitors on human neuroblastoma cell survival were studied in vitro. We have recently shown on IMR-32, CHP‑134, and LA-N-1 neuroblastoma cells that targeting GD2 with the mAb decreases cell viability of the cell lines. In this study we used cytotoxicity assays, proteomic arrays and immunoblotting to evaluate the response of the three cell lines to the anti‑GD2 14G2a mAb and specific PI3K/Akt/mTOR pathway inhibitors. We show here that the mAb modulates intracellular signal transduction through changes in several kinases and their substrates phosphorylation. More detailed analysis of the PI3K/Akt/mTOR pathway showed significant decrease in activity of Akt, mTOR, p70 S6 and 4E-BP1 proteins and transient increase in PTEN (a suppressor of the pathway), leading to inhibition of the signaling network responsible for stimulation of translation and proliferation. Additionally, combining the GD2-specific 14G2a mAb with an Akt inhibitor (perifosine), dual mTOR/PI3K inhibitors (BEZ-235 and SAR245409), and a pan-PI3K inhibitor (LY294002) was shown to enhance cytotoxic effects against IMR-32, CHP‑134 and LA-N-1 cells. Our study extends knowledge on mechanisms of action of the 14G2a mAb on the neuroblastoma cells. Also, it stresses the need for further delineation of molecular signal orchestration aimed at more reasonable selection of drugs to target key cellular pathways in quest for better cure for neuroblastoma patients. PMID:26134970

  20. GPU-Accelerated Denoising in 3D (GD3D)

    2013-10-01

    The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer themore » second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.« less

  1. Luminescence and magnetic properties of novel nanoparticle-sheathed 3D Micro-Architectures of Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) for bifunctional application

    NASA Astrophysics Data System (ADS)

    Krishnan, Rajagopalan; Thirumalai, Jagannathan; Kathiravan, Arunkumar

    2015-01-01

    For the first time, we report the successful synthesis of novel nanoparticle-sheathed bipyramid-like and almond-like Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) 3D hierarchical microstructures through a simple disodium ethylenediaminetetraacetic acid (Na2EDTA) facilitated hydrothermal method. Interestingly, time-dependent experiments confirm that the assembly-disassembly process is responsible for the formation of self-aggregated 3D architectures via Ostwald ripening phenomena. The resultant products are characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and magnetic measurements. The growth and formation mechanisms of the self-assembled 3D micro structures are discussed in detail. To confirm the presence of all the elements in the microstructure, the energy loss induced by the K, L shell electron ionization is observed in order to map the Fe, Gd, Mo, O, and Eu components. The photo luminescence properties of Fe0.5R0.5(MoO4)1.5 doped with Eu3+, Tb3+, Dy3+ are investigated. The room temperature and low temperature magnetic properties suggest that the interaction between the local-fields introduced by the magnetic Fe3+ ions and the R3+ (La, Gd) ions in the dodecahedral sites determine the magnetism in Fe0.5R0.5(MoO4)1.5:Eu3+. This work provides a new approach to synthesizing the novel Fe0.5R0.5(MoO4)1.5:Ln3+ for bi-functional magnetic and luminescence applications.

  2. A single native ganglioside GM1-binding site is sufficient for cholera toxin to bind to cells and complete the intoxication pathway.

    PubMed

    Jobling, Michael G; Yang, Zhijie; Kam, Wendy R; Lencer, Wayne I; Holmes, Randall K

    2012-01-01

    Cholera toxin (CT) from Vibrio cholerae is responsible for the majority of the symptoms of the diarrheal disease cholera. CT is a heterohexameric protein complex with a 240-residue A subunit and a pentameric B subunit of identical 103-residue B polypeptides. The A subunit is proteolytically cleaved within a disulfide-linked loop to generate the A1 and A2 fragments. The B subunit of wild-type (wt) CT binds 5 cell surface ganglioside GM(1) (GM(1)) molecules, and the toxin-GM(1) complex traffics from the plasma membrane (PM) retrograde through endosomes and the Golgi apparatus to the endoplasmic reticulum (ER). From the ER, the enzymatic A1 fragment retrotranslocates to the cytosol to cause disease. Clustering of GM(1) by multivalent toxin binding can structurally remodel cell membranes in ways that may assist toxin uptake and retrograde trafficking. We have recently found, however, that CT may traffic from the PM to the ER by exploiting an endogenous glycosphingolipid pathway (A. A. Wolf et al., Infect. Immun. 76:1476-1484, 2008, and D. J. F. Chinnapen et al., Dev. Cell 23:573-586, 2012), suggesting that multivalent binding to GM(1) is dispensable. Here we formally tested this idea by creating homogenous chimeric holotoxins with defined numbers of native GM(1) binding sites from zero (nonbinding) to five (wild type). We found that a single GM(1) binding site is sufficient for activity of the holotoxin. Therefore, remodeling of cell membranes by mechanisms that involve multivalent binding of toxin to GM(1) receptors is not essential for toxicity of CT. Through multivalent binding to its lipid receptor, cholera toxin (CT) can remodel cell membranes in ways that may assist host cell invasion. We recently found that CT variants which bind no more than 2 receptor molecules do exhibit toxicity, suggesting that CT may be able to enter cells by coopting an endogenous lipid sorting pathway without clustering receptors. We tested this idea directly by using purified variants

  3. Biosynthesis of ganglioside mimics in Campylobacter jejuni OH4384. Identification of the glycosyltransferase genes, enzymatic synthesis of model compounds, and characterization of nanomole amounts by 600-mhz (1)h and (13)c NMR analysis.

    PubMed

    Gilbert, M; Brisson, J R; Karwaski, M F; Michniewicz, J; Cunningham, A M; Wu, Y; Young, N M; Wakarchuk, W W

    2000-02-11

    We have applied two strategies for the cloning of four genes responsible for the biosynthesis of the GT1a ganglioside mimic in the lipooligosaccharide (LOS) of a bacterial pathogen, Campylobacter jejuni OH4384, which has been associated with Guillain-Barré syndrome. We first cloned a gene encoding an alpha-2, 3-sialyltransferase (cst-I) using an activity screening strategy. We then used nucleotide sequence information from the recently completed sequence from C. jejuni NCTC 11168 to amplify a region involved in LOS biosynthesis from C. jejuni OH4384. The LOS biosynthesis locus from C. jejuni OH4384 is 11.47 kilobase pairs and encodes 13 partial or complete open reading frames, while the corresponding locus in C. jejuni NCTC 11168 spans 13.49 kilobase pairs and contains 15 open reading frames, indicating a different organization between these two strains. Potential glycosyltransferase genes were cloned individually, expressed in Escherichia coli, and assayed using synthetic fluorescent oligosaccharides as acceptors. We identified genes encoding a beta-1, 4-N-acetylgalactosaminyl-transferase (cgtA), a beta-1, 3-galactosyltransferase (cgtB), and a bifunctional sialyltransferase (cst-II), which transfers sialic acid to O-3 of galactose and to O-8 of a sialic acid that is linked alpha-2,3- to a galactose. The linkage specificity of each identified glycosyltransferase was confirmed by NMR analysis at 600 MHz on nanomole amounts of model compounds synthesized in vitro. Using a gradient inverse broadband nano-NMR probe, sequence information could be obtained by detection of (3)J(C,H) correlations across the glycosidic bond. The role of cgtA and cst-II in the synthesis of the GT1a mimic in C. jejuni OH4384 were confirmed by comparing their sequence and activity with corresponding homologues in two related C. jejuni strains that express shorter ganglioside mimics in their LOS.

  4. The Divergent CD8+ T Cell Adjuvant Properties of LT-IIb and LT-IIc, Two Type II Heat-Labile Enterotoxins, Are Conferred by Their Ganglioside-Binding B Subunits

    PubMed Central

    Hu, John C.; Greene, Christopher J.; King-Lyons, Natalie D.; Connell, Terry D.

    2015-01-01

    Poor immune responses elicited by vaccine antigens can be enhanced by the use of appropriate adjuvants. Type II heat-labile enterotoxins (HLT) produced by Escherichia coli are extremely potent adjuvants that augment both humoral and cellular immunity to co-administered antigens. Recent findings demonstrate that LT-IIb and LT-IIc, two type II HLT adjuvants, exhibit potent, yet distinguishable CD8+ T cell adjuvant properties. While LT-IIc elicits a robust and rapid response at one week after administration, LT-IIb engenders a more gradual and slower expansion of antigen-specific CD8+ T cells that correlates with improved immunity. The variations in immune effects elicited by the HLT adjuvants have been generally attributed to their highly divergent B subunits that mediate binding to various gangliosides on cell surfaces. Yet, HLT adjuvants with point mutations in the B subunit that significantly alter ganglioside binding retain similar adjuvant functions. Therefore, the contribution of the B subunits to adjuvanticity remains unclear. To investigate the influence of the B subunits on the enhancement of immune responses by LT-IIb and LT-IIc, chimeric HLT were engineered in which the B subunits of the two adjuvants were exchanged. Comparing the immune potentiating characteristics of both native and chimeric HLT adjuvants, it was found that not all the adjuvant characteristics of the HLT adjuvants were modulated by the respective B subunits. Specifically, the differences in the CD8+ T cell kinetics and protective responses elicited by LT-IIb and LT-IIc did indeed followed their respective B subunits. However, induction of IL-1 from macrophages and the capacity to intoxicate cells in a mouse Y1 adrenal cell bioassay did not correlate with the B subunits. Therefore, it is likely that additional factors other than the B subunits contribute to the effects elicited by the HLT adjuvants. PMID:26565800

  5. Evidence that small molecule enhancement of β-hexosaminidase activity corrects the behavioral phenotype in Dutch APP(E693Q) mice through reduction of ganglioside-bound Aβ.

    PubMed

    Knight, E M; Williams, H N; Stevens, A C; Kim, S H; Kottwitz, J C; Morant, A D; Steele, J W; Klein, W L; Yanagisawa, K; Boyd, R E; Lockhart, D J; Sjoberg, E R; Ehrlich, M E; Wustman, B A; Gandy, S

    2015-02-01

    Certain mutant Alzheimer's amyloid-β (Aβ) peptides (that is, Dutch mutant APP(E693Q)) form complexes with gangliosides (GAβ). These mutant Aβ peptides may also undergo accelerated aggregation and accumulation upon exposure to GM2 and GM3. We hypothesized that increasing β-hexosaminidase (β-hex) activity would lead to a reduction in GM2 levels, which in turn, would cause a reduction in Aβ aggregation and accumulation. The small molecule OT1001 is a β-hex-targeted pharmacological chaperone with good bioavailability, blood-brain barrier penetration, high selectivity for β-hex and low cytotoxicity. Dutch APP(E693Q) transgenic mice accumulate oligomeric Aβ as they age, as well as Aβ oligomer-dose-dependent anxiety and impaired novel object recognition (NOR). Treatment of Dutch APP(E693Q) mice with OT1001 caused a dose-dependent increase in brain β-hex levels up to threefold over those observed at baseline. OT1001 treatment was associated with reduced anxiety, improved learning behavior in the NOR task and dramatically reduced GAβ accumulation in the subiculum and perirhinal cortex, both of which are brain regions required for normal NOR. Pharmacological chaperones that increase β-hex activity may be useful in reducing accumulation of certain mutant species of Aβ and in preventing the associated behavioral pathology. PMID:25349165

  6. Novel Anti-idiotype Antibody Therapy for Lipooligosaccharide-Induced Experimental Autoimmune Neuritis: Use Relevant to Guillain-Barré Syndrome

    PubMed Central

    Usuki, S.; Taguchi, K.; Thompson, S.A.; Chapman, P.B.; Yu, R.K.

    2010-01-01

    Campylobacteriosis is a frequent antecedent event in Guillain-Barré syndrome (GBS), inducing high-titer serum antibodies for ganglioside antigens in the peripheral nervous system (PNS). Molecular mimicry between the lipooligosaccharide (LOS) component of Campylobacter jejuni and human peripheral nerve gangliosides is believed to play an important role in the pathogenesis of GBS. Conventional treatment strategies for patients with GBS include plasmapheresis, intravenous immunoglobulin (IVIG), and immunosuppression, which are invasive or relatively ineffective. In this study, we used our animal model of GBS, in which Lewis rats were immunized with GD3-like LOS isolated from C. jejuni. The animals developed anti-GD3 ganglioside antibodies and manifested neuromuscular dysfunction. To develop novel therapeutic strategies, we treated the animals by intraperitoneal administration of an anti-GD3 antiidiotype monoclonal antibody (BEC2) that specifically interacts with the pathogenic antibody. The treated animals had a remarkable reduction of anti-GD3 antibody titers and improvement of motor nerve functions. The results suggest that ganglioside mimics, such as antiidiotype antibodies, may be powerful reagents for therapeutic intervention in GBS by neutralizing specific pathogenic antiganglioside antibodies. PMID:20077429

  7. Preparation and characterization of [Gd(hfac)3(DTBN)(H2O)] (DTBN = di-t-butyl nitroxide). Ferromagnetic Gd(3+)-Gd3+ super-superexchange.

    PubMed

    Kanetomo, Takuya; Ishida, Takayuki

    2014-03-01

    The intramolecular radical-Gd antiferromagnetic coupling (2J1/k(B) = -11.6 K) is notably strong, as expected from our molecular design, and the intermolecular exchange coupling along the Gd-O-H···O-Gd bridges is unexpectedly ferromagnetic with the largest Gd···Gd coupling ever known (2J2/k(B) = +0.12 K).

  8. Differential Anatomical Expression of Ganglioside GM1 Species Containing d18:1 or d20:1 Sphingosine Detected by MALDI Imaging Mass Spectrometry in Mature Rat Brain

    PubMed Central

    Weishaupt, Nina; Caughlin, Sarah; Yeung, Ken K.-C.; Whitehead, Shawn N.

    2015-01-01

    GM1 ganglioside plays a role in essential neuronal processes, including differentiation, survival, and signaling. Yet, little is known about GM1 species with different sphingosine bases, such as the most abundant species containing 18 carbon atoms in the sphingosine chain (GM1d18:1), and the less abundant containing 20 carbon atoms (GM1d20:1). While absent in the early fetal brain, GM1d20:1 continues to increase throughout pre- and postnatal development and into old age, raising questions about the functional relevance of the GM1d18:1 to GM1d20:1 ratio. Matrix-assisted laser desorption/ionization imaging mass spectrometry is a novel technology that allows differentiation between these two GM1 species and quantification of their expression within an anatomical context. Using this technology, we find GM1d18:1/d20:1 expression ratios are highly specific to defined anatomical brain regions in adult rats. Thus, the ratio was significantly different among different thalamic nuclei and between the corpus callosum and internal capsule. Differential GM1d18:1/GM1d20:1 ratios measured in hippocampal subregions in rat brain complement previous studies conducted in mice. Across layers of the sensory cortex, opposing expression gradients were found for GM1d18:1 and GM1d20:1. Superficial layers demonstrated lower GM1d18:1 and higher GM1d20:1 signal than other layers, while in deep layers GM1d18:1 expression was relatively high and GM1d20:1 expression low. By far the highest GM1d18:1/d20:1 ratio was found in the amygdala. Differential expression of GM1 with d18:1- or d20:1-sphingosine bases in the adult rat brain suggests tight regulation of expression and points toward a distinct functional relevance for each of these GM1 species in neuronal processes. PMID:26648849

  9. Materials Data on Gd3YO6 (SG:148) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-10-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  10. Materials Data on Gd3InO6 (SG:148) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-10-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  11. Materials Data on Gd3S4 (SG:220) by Materials Project

    SciTech Connect

    Kristin Persson

    2015-03-24

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  12. MRI sensing of neurotransmitters with a crown ether appended Gd(3+) complex.

    PubMed

    Oukhatar, Fatima; Même, Sandra; Même, William; Szeremeta, Frédéric; Logothetis, Nikos K; Angelovski, Goran; Tóth, Éva

    2015-02-18

    Molecular magnetic resonance imaging (MRI) approaches that detect biomarkers associated with neural activity would allow more direct observation of brain function than current functional MRI based on blood-oxygen-level-dependent contrast. Our objective was to create a synthetic molecular platform with appropriate recognition moieties for zwitterionic neurotransmitters that generate an MR signal change upon neurotransmitter binding. The gadolinium complex (GdL) we report offers ditopic binding for zwitterionic amino acid neurotransmitters, via interactions (i) between the positively charged and coordinatively unsaturated metal center and the carboxylate function and (ii) between a triazacrown ether and the amine group of the neurotransmitters. GdL discriminates zwitterionic neurotransmitters from monoamines. Neurotransmitter binding leads to a remarkable relaxivity change, related to a decrease in hydration number. GdL was successfully used to monitor neural activity in ex vivo mouse brain slices by MRI. PMID:25496344

  13. Materials Data on Gd3Pd2 (SG:127) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  14. Materials Data on Gd3Al5O12 (SG:230) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  15. Materials Data on Gd3Co11B4 (SG:191) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-07-09

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  16. Materials Data on Gd3OsO7 (SG:63) by Materials Project

    DOE Data Explorer

    Kristin Persson

    2016-02-10

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  17. Carbohydrate Recognition Properties of Human Ficolins

    PubMed Central

    Gout, Evelyne; Garlatti, Virginie; Smith, David F.; Lacroix, Monique; Dumestre-Pérard, Chantal; Lunardi, Thomas; Martin, Lydie; Cesbron, Jean-Yves; Arlaud, Gérard J.; Gaboriaud, Christine; Thielens, Nicole M.

    2010-01-01

    Ficolins are oligomeric innate immune recognition proteins consisting of a collagen-like region and a fibrinogen-like recognition domain that bind to pathogen- and apoptotic cell-associated molecular patterns. To investigate their carbohydrate binding specificities, serum-derived L-ficolin and recombinant H- and M-ficolins were fluorescently labeled, and their carbohydrate binding ability was analyzed by glycan array screening. L-ficolin preferentially recognized disulfated N-acetyllactosamine and tri- and tetrasaccharides containing terminal galactose or N-acetylglucosamine. Binding was sensitive to the position and orientation of the bond between N-acetyllactosamine and the adjacent carbohydrate. No significant binding of H-ficolin to any of the 377 glycans probed could be detected, providing further evidence for its poor lectin activity. M-ficolin bound preferentially to 9-O-acetylated 2-6-linked sialic acid derivatives and to various glycans containing sialic acid engaged in a 2-3 linkage. To further investigate the structural basis of sialic acid recognition by M-ficolin, point mutants were produced in which three residues of the fibrinogen domain were replaced by their counterparts in L-ficolin. Mutations G221F and A256V inhibited binding to the 9-O-acetylated sialic acid derivatives, whereas Y271F abolished interaction with all sialic acid-containing glycans. The crystal structure of the Y271F mutant fibrinogen domain was solved, showing that the mutation does not alter the structure of the ligand binding pocket. These analyses reveal novel ficolin ligands such as sulfated N-acetyllactosamine (L-ficolin) and gangliosides (M-ficolin) and provide precise insights into the sialic acid binding specificity of M-ficolin, emphasizing the essential role of Tyr271 in this respect. PMID:20032467

  18. Neobiosynthesis of Glycosphingolipids by Plasma Membrane-associated Glycosyltransferases*

    PubMed Central

    Crespo, Pilar M.; Demichelis, Vanina Torres; Daniotti, José L.

    2010-01-01

    Gangliosides, complex glycosphingolipids containing sialic acids, are synthesized in the endoplasmic reticulum and in the Golgi complex. These neobiosynthesized gangliosides move via vesicular transport to the plasma membrane, becoming components of the external leaflet. Gangliosides can undergo endocytosis followed by recycling to the cell surface or sorting to the Golgi complex or lysosomes for remodeling and catabolism. Recently, glycosphingolipid catabolic enzymes (glycohydrolases) have been found to be associated with the plasma membrane, where they display activity on the membrane components. In this work, we demonstrated that ecto-ganglioside glycosyltransferases may catalyze ganglioside synthesis outside the Golgi compartment, particularly at the cell surface. Specifically, we report the first direct evidence of expression and activity of CMP-NeuAc:GM3 sialyltransferase (Sial-T2) at the cell surface of epithelial and melanoma cells, with membrane-integrated ecto-Sial-T2 being able to sialylate endogenously synthesized GM3 ganglioside as well as exogenously incorporated substrate. Interestingly, we also showed that ecto-Sial-T2 was able to synthesize GD3 ganglioside at the cell surface using the endogenously synthesized cytidine monophospho-N-acetylneuraminic acid (CMP-NeuAc) available at the extracellular milieu. In addition, the expression of UDP-GalNAc:LacCer/GM3/GD3 N-acetylgalactosaminyltransferase (GalNAc-T) was also detected at the cell surface of epithelial cells, whose catalytic activity was only observed after feeding the cells with exogenous GM3 substrate. Thus, the relative interplay between the plasma membrane-associated glycosyltransferase and glycohydrolase activities, even when acting on a common substrate, emerges as a potential level of regulation of the local glycosphingolipid composition in response to different external and internal stimuli. PMID:20639193

  19. Acidic glycosphingolipids of cock testis elucidated by mass spectrometry and NMR spectroscopy.

    PubMed

    Iga, D P; Iga, S; Larsson, T; Angström, J; Soussi, B; Rakotonirainy, O; Miller-Podraza, H

    1998-12-01

    The main acidic glycosphingolipids (GSLs) of cock testis were identified as GalCer I3-sulfate and gangliosides GM4, GM3, GD3 and GT3. They contained N-acetylneuraminic acid as the major sialic acid, and ceramides composed mainly of sphingosine (dl8:1) and C18-24 non-hydroxy fatty acids. Appreciable amounts of hydroxy fatty acids were detected only in the GM4 preparation.

  20. Effect of the β-propiolactone treatment on the adsorption and fusion of influenza A/Brisbane/59/2007 and A/New Caledonia/20/1999 virus H1N1 on a dimyristoylphosphatidylcholine/ganglioside GM3 mixed phospholipids monolayer at the air-water interface.

    PubMed

    Desbat, Bernard; Lancelot, Eloïse; Krell, Tino; Nicolaï, Marie-Claire; Vogel, Fred; Chevalier, Michel; Ronzon, Frédéric

    2011-11-15

    The production protocol of many whole cell/virion vaccines involves an inactivation step with β-propiolactone (BPL). Despite the widespread use of BPL, its mechanism of action is poorly understood. Earlier work demonstrated that BPL alkylates nucleotide bases, but its interaction with proteins has not been studied in depth. In the present study we use ellipsometry to analyze the influence of BPL treatment of two H1N1 influenza strains, A/Brisbane/59/2007 and A/New Caledonia/20/1999, which are used for vaccine production on an industrial scale. Analyses were conducted using a mixed lipid monolayer containing ganglioside GM3, which functions as the viral receptor. Our results show that BPL treatment of both strains reduces viral affinity for the mixed monolayer and also diminishes the capacity of viral domains to self-assemble. In another series of experiments, the pH of the subphase was reduced from 7.4 to 5 to provoke the pH-induced conformational change of hemagglutinin, which occurs following endocytosis into the endosome. In the presence of the native virus the pH decrease caused a reduction in domain size, whereas lipid layer thickness and surface pressure were increased. These observations are consistent with a fusion of the viral membrane with the lipid monolayer. Importantly, this fusion was not observed with adsorbed inactivated virus, which indicates that BPL treatment inhibits the first step of virus-membrane fusion. Our data also indicate that BPL chemically modifies hemagglutinin, which mediates the interaction with GM3.

  1. Gd3+-DTPA-Meglumine-Anionic Linear Globular Dendrimer G1: Novel Nanosized Low Toxic Tumor Molecular MR Imaging Agent

    PubMed Central

    Darvish Mohamadi, Tahmineh; Ghalandarlaki, Negar; Mehravi, Bita; Shafiee Ardestani, Mehdi; Yaghmaei, Parichehr

    2013-01-01

    Despite the great efforts in the areas of early diagnosis and treatment of cancer, this disease continues to grow and is still a global killer. Cancer treatment efficiency is relatively high in the early stages of the disease. Therefore, early diagnosis is a key factor in cancer treatment. Among the various diagnostic methods, molecular imaging is one of the fastest and safest ones. Because of its unique characteristics, magnetic resonance imaging has a special position in most researches. To increase the contrast of MR images, many pharmaceuticals have been known and used so far. Gadopentetate (with commercial name Magnevist) is the first magnetic resonance imaging contrast media that has been approved by the US Food and Drug Administration. In this study, gadopentetate was first synthesized and then attached to a tree-like polymer called dendrimer which is formed by polyethylene glycol core and surrounding citric acid groups. Stability studies of the drug were carried out to ensure proper synthesis. Then, the uptake of the drug into liver hepatocellular cell line and the drug cytotoxicity were evaluated. Finally, in vitro and in vivo MR imaging were performed with the new synthetic drug. Based on the findings of this research, connecting gadopentetate to dendrimer surface produces a stronger, safer, and more efficient contrast media. Gd(III)-diethylenetriamine pentaacetate-meglumine-dendrimer drug has the ability to enter cells and does not produce significant cytotoxicity. It also increases the relaxivity of tissue and enhances the MR images contrast. The obtained results confirm the hypothesis that the binding of gadopentetate to citric acid dendrimer produces a new, biodegradable, stable, and strong version of the old contrast media. PMID:23533819

  2. Origin and fate of IgE-bearing lymphocytes. II. Gut-associated lymphoid tissue as sites of first appearance of IgE-bearing B lymphocytes and hapten-specific IgE antibody-forming cells in mice immunized with benzylpenicilloyl-keyhole limpet hemocyanin by various routes: relation to asialo GM1 ganglioside+ cells and IgE/CD23 immune complexes.

    PubMed

    Auci, D L; Chice, S M; Heusser, C; Athanassiades, T J; Durkin, H G

    1992-10-01

    The organs in which B cells bearing membrane-bound IgE (sIgE+) and benzylpenicilloyl (BPO)-specific IgE antibody-forming cells (AFC) first appeared were determined in BALB/c mice given BPO-keyhole limpet hemocyanin (10 micrograms) in aluminum hydroxide by various routes (i.p, gavage, s.c., i.v., or i.m.). In mice immunized by the i.p. route, the numbers and location of sIgE+ B cells and asialo GM1 ganglioside (AsGm1+) cells, the location of IgE/CD23 immune complexes, and the numbers of BPO-specific IgE AFC in lymphoid organs were determined. With all routes of immunization, no sIgE+ B cells or BPO-specific IgE AFC were ever detected in any organ before day 8. On day 8, with the s.c., i.v., or i.m. routes, sIgE+ B cells and IgE AFC appeared exclusively in Peyer's patches (PP); with the i.p. or gavage routes, sIgE+ B cells simultaneously appeared in both PP and mesenteric lymph nodes, whereas IgE AFC appeared only in PP. In mice immunized by the i.p. route, IgE/CD23 immune complexes and strikingly increased numbers of AsGm1+ cells transiently appeared only in PP after the appearance and preceding the "disappearance" of the sIgE+ B cells and IgE AFC. The data suggest that specific IgE responses originate in gut-associated lymphoid tissue and appear later in spleen. The data also associate the appearance of IgE/CD23 immune complexes and AsGm1+ cells with the "disappearance" of sIgE+ B cells and IgE AFC from PP.

  3. Structural characterization of Campylobacter jejuni lipooligosaccharide outer cores associated with Guillain-Barre and Miller Fisher syndromes.

    PubMed

    Godschalk, Peggy C R; Kuijf, Mark L; Li, Jianjun; St Michael, Frank; Ang, C Wim; Jacobs, Bart C; Karwaski, Marie-France; Brochu, Denis; Moterassed, Ali; Endtz, Hubert P; van Belkum, Alex; Gilbert, Michel

    2007-03-01

    Molecular mimicry between lipooligosaccharides (LOS) of Campylobacter jejuni and gangliosides in peripheral nerves plays a crucial role in the pathogenesis of C. jejuni-related Guillain-Barré syndrome (GBS). We have analyzed the LOS outer core structures of 26 C. jejuni strains associated with GBS and its variant, Miller Fisher syndrome (MFS), by capillary electrophoresis coupled with electrospray ionization mass spectrometry. Sixteen out of 22 (73%) GBS-associated and all 4 (100%) MFS-associated strains expressed LOS with ganglioside mimics. GM1a was the most prevalent ganglioside mimic in GBS-associated strains (10/22, 45%), and in eight of these strains, GM1a was found in combination with GD1a mimics. All seven strains isolated from patients with ophthalmoplegia (GBS or MFS) expressed disialylated (GD3 or GD1c) mimics. Three out of 22 GBS-associated strains (14%) did not express sialylated ganglioside mimics because their LOS locus lacked the genes necessary for sialylation. Three other strains (14%) did not express ganglioside mimics because of frameshift mutations in either the cstII sialyltransferase gene or the cgtB galactosyltransferase gene. It is not possible to determine if these mutations were already present during C. jejuni infection. This is the first report in which mass spectrometry combined with DNA sequence data were used to infer the LOS outer core structures of a large number of neuropathy-associated C. jejuni strains. We conclude that molecular mimicry between gangliosides and C. jejuni LOS is the presumable pathogenic mechanism in most cases of C. jejuni-related GBS. However, our findings suggest that in some cases, other mechanisms may play a role. Further examination of the disease etiology in these patients is mandatory.

  4. Evidence for the involvement of lipid rafts localized at the ER-mitochondria associated membranes in autophagosome formation.

    PubMed

    Garofalo, Tina; Matarrese, Paola; Manganelli, Valeria; Marconi, Matteo; Tinari, Antonella; Gambardella, Lucrezia; Faggioni, Alberto; Misasi, Roberta; Sorice, Maurizio; Malorni, Walter

    2016-06-01

    Mitochondria-associated membranes (MAMs) are subdomains of the endoplasmic reticulum (ER) that interact with mitochondria. This membrane scrambling between ER and mitochondria appears to play a critical role in the earliest steps of autophagy. Recently, lipid microdomains, i.e. lipid rafts, have been identified as further actors of the autophagic process. In the present work, a series of biochemical and molecular analyses has been carried out in human fibroblasts with the specific aim of characterizing lipid rafts in MAMs and to decipher their possible implication in the autophagosome formation. In fact, the presence of lipid microdomains in MAMs has been detected and, in these structures, a molecular interaction of the ganglioside GD3, a paradigmatic "brick" of lipid rafts, with core-initiator proteins of autophagy, such as AMBRA1 and WIPI1, was revealed. This association seems thus to take place in the early phases of autophagic process in which MAMs have been hypothesized to play a key role. The functional activity of GD3 was suggested by the experiments carried out by knocking down ST8SIA1 gene expression, i.e., the synthase that leads to the ganglioside formation. This experimental condition results in fact in the impairment of the ER-mitochondria crosstalk and the subsequent hindering of autophagosome nucleation. We thus hypothesize that MAM raft-like microdomains could be pivotal in the initial organelle scrambling activity that finally leads to the formation of autophagosome.

  5. Transition to a Virtually Incompressible Oxide Phase at a Shock Pressure of 120 GPa (1.2 Mbar): Gd3Ga5O12

    SciTech Connect

    Mashimo, T; Chau, R; Zhang, Y; Kobayoshi, T; Sekine, T; Fukuoka, K; Syono, Y; Kodama, M; Nellis, W J

    2005-09-19

    Cubic, single-crystal, transparent Gd{sub 3}Ga{sub 5}O{sub 12} has a density of 7.10 g/cm{sup 3}, a Hugoniot elastic limit (HEL) of 30 GPa, and undergoes a continuous phase transition from 65 GPa to a quasi-incompressible (QI) phase at 120 GPa. Only diamond has a larger HEL. The QI phase of Gd{sub 3}Ga{sub 5}O{sub 12} is more incompressible than diamond from 170 to 260 GPa. Electrical conductivity measurements indicate the QI phase has a bandgap of 3.1 eV. Gd{sub 3}Ga{sub 5}O{sub 12} can be used to obtain substantially higher pressures and lower temperatures in metallic fluid hydrogen than was achieved previously by shock reverberation between Al{sub 2}O{sub 3} disks. Dynamic compression achieves pressures, densities, and temperatures that enable investigation of ultracondensed matter at conditions yet to be achieved by any other technique. The prototypical example is observation of minimum metallic conductivity (MMC) of dense fluid hydrogen at 140 GPa, nine-fold compression of liquid density, and {approx}3000 K [1-3]. The high pressure and density and relatively low temperature are achieved by multiple-shock compression [2]. Temperature T is relatively low in the sense that T/TP{sub F} {approx} 0.01, where T{sub F} is the Fermi temperature. The time scale of compression is sufficiently long to achieve thermal equilibrium and sufficiently short so the process is adiabatic. Similar results are obtained for oxygen [4] and nitrogen [5]. Fluid Cs and Rb undergo the same transition at 2000 K near their liquid-vapor critical points [6]. All five elemental fluids have essentially the same value of MMC and the density dependences of their semiconductivities scale with the quantum-mechanical charge-density distributions of the respective atoms [5]. Liquid H{sub 2} is one of the most compressible of all materials. In this paper, we report that the dielectric crystal Gd{sub 3}Ga{sub 5}O{sub 12} (GGG) transitions to a virtually incompressible phase at 120 GPa shock pressure.

  6. Exceptionally high magnetization of stoichiometric Y3Fe5O12 epitaxial films grown on Gd3Ga5O12

    NASA Astrophysics Data System (ADS)

    Gallagher, James C.; Yang, Angela S.; Brangham, Jack T.; Esser, Bryan D.; White, Shane P.; Page, Michael R.; Meng, Keng-Yuan; Yu, Sisheng; Adur, Rohan; Ruane, William; Dunsiger, Sarah R.; McComb, David W.; Yang, Fengyuan; Hammel, P. Chris

    2016-08-01

    The saturation magnetization of Y3Fe5O12 (YIG) epitaxial films 4 to 250 nm in thickness has been determined by complementary measurements including the angular and frequency dependencies of the ferromagnetic resonance fields as well as magnetometry measurements. The YIG films exhibit state-of-the-art crystalline quality, proper stoichiometry, and pure Fe3+ valence state. The values of YIG magnetization obtained from all the techniques significantly exceed previously reported values for single crystal YIG and the theoretical maximum. This enhancement of magnetization, not attributable to off-stoichiometry or other defects in YIG, opens opportunities for tuning magnetic properties in epitaxial films of magnetic insulators.

  7. Alpha-gamma pulse-shape discrimination in Gd3Al2Ga3O12 (GAGG):Ce3+ crystal scintillator using shape indicator

    NASA Astrophysics Data System (ADS)

    Tamagawa, Yoichi; Inukai, Yuji; Ogawa, Izumi; Kobayashi, Masaaki

    2015-09-01

    The pulse-shape discrimination (PSD) in a GAGG single-crystal scintillator was studied by using a shape indicator (SI) parameter of the optimal digital filter method. SI is one of the most useful PSD methods that use typical pulse shapes. Excellent discrimination between 0.662 MeV γ-rays and 5.48 MeV α-rays was achieved. For a cut at SI=0.0056, 99.95% of the γ-rays and only 0.22% of the α-rays were retained. Selection of background events (γ and α) in the GAGG scintillator was achieved by using the PSD method.

  8. Multifunctional Magnetic Gd(3+) -Based Coordination Polymer Nanoparticles: Combination of Magnetic Resonance and Multispectral Optoacoustic Detections for Tumor-Targeted Imaging in vivo.

    PubMed

    An, Qiao; Liu, Jing; Yu, Meng; Wan, Jiaxun; Li, Dian; Wang, Changchun; Chen, Chunying; Guo, Jia

    2015-11-11

    To overcome traditional barriers in optical imaging and microscopy, optoacoustic-imaging has been changed to combine the accuracy of spectroscopy with the depth resolution of ultrasound, achieving a novel modality with powerful in vivo imaging. However, magnetic resonance imaging provides better spatial and anatomical resolution. Thus, a single hybrid nanoprobe that allows for simultaneous multimodal imaging is significant not only for cutting edge research in imaging science, but also for accurate clinical diagnosis. A core-shell-structured coordination polymer composite microsphere has been designed for in vivo multimodality imaging. It consists of a Fe3 O4 nanocluster core, a carbon sandwiched layer, and a carbocyanine-Gd(III) (Cy-Gd(III) ) coordination polymer outer shell (Fe3 O4 @C@Cy-Gd(III) ). Folic acid-conjugated poly(ethylene glycol) chains are embedded within the coordination polymer shell to achieve extended circulation and targeted delivery of probe particles in vivo. Control of Fe3 O4 core grain sizes results in optimal r2 relaxivity (224.5 × 10(-3) m(-1) s(-1) ) for T2 -weighted magnetic resonance imaging. Cy-Gd(III) coordination polymers are also regulated to obtain a maximum 25.1% of Cy ligands and 5.2% of Gd(III) ions for near-infrared fluorescence and T1 -weighted magnetic resonance imaging, respectively. The results demonstrate their impressive abilities for targeted, multimodal, and reliable imaging.

  9. Core/shell structured NaYF4:Yb3+/Er3+/Gd+3 nanorods with Au nanoparticles or shells for flexible amorphous silicon solar cells

    NASA Astrophysics Data System (ADS)

    Li, Z. Q.; Li, X. D.; Liu, Q. Q.; Chen, X. H.; Sun, Z.; Liu, C.; Ye, X. J.; Huang, S. M.

    2012-01-01

    A simple approach for preparing near-infrared (NIR) to visible upconversion (UC) NaYF4:Yb/Er/Gd nanorods in combination with gold nanostructures has been reported. The grown UC nanomaterials with Au nanostructures have been applied to flexible amorphous silicon solar cells on the steel substrates to investigate their responses to sub-bandgap infrared irradiation. Photocurrent-voltage measurements were performed on the solar cells. It was demonstrated that UC of NIR light led to a 16-fold to 72-fold improvement of the short-circuit current under 980 nm illumination compared to a cell without upconverters. A maximum current of 1.16 mA was obtained for the cell using UC nanorods coated with Au nanoparticles under 980 nm laser illumination. This result corresponds to an external quantum efficiency of 0.14% of the solar cell. Mechanisms of erbium luminescence in the grown UC nanorods were analyzed and discussed.

  10. Serotype-specific differences in inhibition of reovirus infectivity by human-milk glycans are determined by viral attachment protein σ1.

    PubMed

    Iskarpatyoti, Jason A; Morse, E Ashley; McClung, R Paul; Ikizler, Miné; Wetzel, J Denise; Contractor, Nikhat; Dermody, Terence S

    2012-11-25

    Human milk contains many bioactive components, including secretory IgA, oligosaccharides, and milk-associated proteins. We assessed the antiviral effects of several components of milk against mammalian reoviruses. We found that glucocerebroside (GCB) inhibited the infectivity of reovirus strain type 1 Lang (T1L), whereas gangliosides GD3 and GM3 and 3'-sialyllactose (3SL) inhibited the infectivity of reovirus strain type 3 Dearing (T3D). Agglutination of erythrocytes mediated by T1L and T3D was inhibited by GD3, GM3, and bovine lactoferrin. Additionally, α-sialic acid, 3SL, 6'-sialyllactose, sialic acid, human lactoferrin, osteopontin, and α-lactalbumin inhibited hemagglutination mediated by T3D. Using single-gene reassortant viruses, we found that serotype-specific differences segregate with the gene encoding the viral attachment protein. Furthermore, GD3, GM3, and 3SL inhibit T3D infectivity by blocking binding to host cells, whereas GCB inhibits T1L infectivity post-attachment. These results enhance an understanding of reovirus cell attachment and define a mechanism for the antimicrobial activity of human milk.

  11. Characterization of moose intestinal glycosphingolipids.

    PubMed

    Johansson, Miralda Madar; Dedic, Benjamin; Lundholm, Klara; Branzell, Filip Berner; Barone, Angela; Benktander, John; Teneberg, Susann

    2015-08-01

    As a part of a systematic investigation of the species-specific expression of glycosphingolipids, acid and non-acid glycosphingolipids were isolated from three small intestines and one large intestine of the moose (Alces alces). The glycosphingolipids were characterized by binding of monoclonal antibodies, lectins and bacteria in chromatogram binding assays, and by mass spectrometry. The non-acid fractions were complex mixtures, and all had glycosphingolipids belonging to the lacto- and neolactoseries (lactotriaosylceramide, lactotetraosylceramide, neolactotetraosylceramide, Galα3-Le(x) hexaosylceramide, and lacto-neolactohexaosylceramide), globo-series (globotriaosylceramide and globotetraosylceramide), and isogloboseries (isoglobotriaosylceramide). Penta- and heptaglycosylceramides with terminal Galili determinants were also characterized. Furthermore, glycosphingolipids with terminal blood group O determinants (H triaosylceramide, H type 2 pentaosylceramide, H type 1 penta- and heptaosylceramide) were characterized in two of the moose small intestines, and in the one large intestine, while the third small intestine had glycosphingolipids with terminal blood group A determinants (A tetraosylceramide, A type 1 hexa- and octaosylceramide, A dodecaosylceramide). The acid glycosphingolipid fractions of moose small and large intestine contained sulfatide, and the gangliosides GM3, GD3, GD1a, GD1b, and also NeuGc and NeuAc variants of the Sd(a) ganglioside and the sialyl-globopenta/SSEA-4 ganglioside. In humans, the NeuAc-globopenta/SSEA-4 ganglioside is a marker of embryonic and adult stem cells, and is also expressed in several human cancers. This is the first time sialyl-globopentaosylceramide/SSEA-4 has been characterized in a fully differentiated normal tissue, and also the first time NeuGc-globopentaosylceramide has been characterized.

  12. Bacterial synthesis of polysialic acid lactosides in recombinant Escherichia coli K-12.

    PubMed

    Richard, Emeline; Buon, Laurine; Drouillard, Sophie; Fort, Sébastien; Priem, Bernard

    2016-07-01

    Bacterial polysialyltransferases (PSTs) are processive enzymes involved in the synthesis of polysialic capsular polysaccharides. They can also synthesize polysialic acid in vitro from disialylated and trisialylated lactoside acceptors, which are the carbohydrate moieties of GD3 and GT3 gangliosides, respectively. Here, we engineered a non-pathogenic Escherichia coli strain that overexpresses recombinant sialyltransferases and sialic acid synthesis genes and can convert an exogenous lactoside into polysialyl lactosides. Several PSTs were assayed for their ability to synthesize polysialyl lactosides in the recombinant strains. Fed-batch cultures produced α-2,8 polysialic acid or alternate α-2,8-2,9 polysialic acid in quantities reaching several grams per liter. Bacterial culture in the presence of propargyl-β-lactoside as the exogenous acceptor led to the production of conjugatable polysaccharides by means of copper-assisted click chemistry. PMID:26927318

  13. Lysis of human tumor cell lines by canine complement plus monoclonal antiganglioside antibodies or natural canine xenoantibodies.

    PubMed

    Helfand, S C; Hank, J A; Gan, J; Sondel, P M

    1996-01-10

    Because certain antiganglioside monoclonal antibodies can facilitate antibody-dependent cellular cytotoxicity against GD2+ ganglioside-bearing human and canine tumor cells, we wished to determine if clinically relevant antiganglioside monoclonal antibodies (Mabs) could also fix canine complement to lyse tumor cells in vitro. Using flow cytometry, human tumor cell lines (M21 melanoma and OHS osteosarcoma) were shown to highly express ganglioside GD2 and, to a lesser degree, GD3. In 51Cr release assays, M21 cells were lysed with canine serum, as a source of complement, plus either Mab 14.G2a or its mouse-human chimera, ch 14.18, specific for GD2. Heating canine serum abrogated its lytic activity and addition of rabbit complement reconstituted M21 lysis. Similar results were obtained with M21 cells when Mab R24 (against GD3) and canine serum were used. OHS cells were also lysed with canine serum plus Mab 14.G2a and lytic activity was abolished by heating canine serum but reconstituted with rabbit complement. Alone, canine serum or Mabs were not lytic to M21 or OHS cells. Conversely, human neuroblastoma (LAN-5) and K562 erythroleukemia cells were lysed by canine serum alone which was shown by flow cytometry to contain naturally occurring canine IgM antibodies that bound LAN-5 and K562 cells. The lytic activity of canine serum for LAN-5 or K562 cells was abolished by heating and restored by addition of either human or rabbit complement. Thus, human tumor cell lines can be lysed with antiganglioside Mabs through fixation and activation of canine complement-dependent lytic pathways. Canine xenoantibodies also mediate complement-dependent cytotoxicity of some human tumor cell lines. Together, these results are significant because they demonstrate an antitumor effect of the canine immune system which is of potential importance for cancer immunotherapy in a promising animal model.

  14. Radioimmune assay of ganglioside GM/sub 1/ synthase using cholera toxin

    SciTech Connect

    Honke, K.; Taniguchi, N.; Makita, A.

    1986-01-01

    A radioimmune assay for uridine 5'-diphosphate-galactose (UDP-Gal):GM/sub 2/ galactosyltransferase, which synthesizes GM/sub 1/, has been developed utilizing cholera toxin. This assay is more sensitive and simpler than previously used assays. Radioactive nucleotide substrate and GM/sub 2/ were incubated with an enzyme sample, and a radiolabeled product, GM/sub 1/, was reacted with cholera toxin. The GM/sub 1/-cholera toxin complex was further reacted with anti-cholera toxin and Staphylococcus aureus cell suspension. The resulting complex was transferred onto a nitrocellulose membrane and quantitated by liquid scintillation counting. This assay was found to be sensitive for the detection of 100 pmol of the reaction product, GM/sub 1/. With this assay method, some properties of the crude enzyme extracts from rat liver were studied. The enzyme had a pH optimum of 6.5-7.0 and required Mn/sup 2 +/. The K/sub m/ values for UDP-Gal and GM/sub 2/ were 0.12 mM and 6 ..mu..M, respectively.

  15. Ganglioside GM1 mimicry in Campylobacter strains from sporadic infections in the United States.

    PubMed

    Nachamkin, I; Ung, H; Moran, A P; Yoo, D; Prendergast, M M; Nicholson, M A; Sheikh, K; Ho, T; Asbury, A K; McKhann, G M; Griffin, J W

    1999-05-01

    To determine whether GM1-like epitopes in Campylobacter species are specific to O serotypes associated with Guillain-Barré syndrome (GBS) or whether they are frequent among random Campylobacter isolates causing enteritis, 275 random enteritis-associated isolates of Campylobacter jejuni were analyzed. To determine whether GM1-like epitopes in Campylobacter species are specific to O serotypes associated with Guillan-Barre syndrome (GBS) or whether they are frequent among random Campylobacter isolates causing enteritis, 275 enteritis-associated isolates, randomly collected in the United States, were analyzed using a cholera-toxin binding assay [corrected]. Overall, 26.2% of the isolates were positive for the GM1-like epitope. Of the 36 different O serotypes in the sample, 21 (58.3%) contained no strains positive for GM1, whereas in 6 serotypes (16.7%), >50% of isolates were positive for GM1. GBS-associated serotypes were more likely to contain strains positive for GM1 than were non-GBS-associated serotypes (37.8% vs. 15.1%, P=.0116). The results suggest that humans are frequently exposed to strains exhibiting GM1-like mimicry and, while certain serotypes may be more likely to possess GM1-like epitopes, the presence of GM1-like epitopes on Campylobacter strains does not itself trigger GBS.

  16. Abnormal lipid rafts related ganglioside expression and signaling in T lymphocytes in immune thrombocytopenia patients.

    PubMed

    Zhang, Xian; Zhang, Donglei; Liu, Wenjie; Li, Huiyuan; Fu, Rongfeng; Liu, Xiaofan; Xue, Feng; Yang, Renchi

    2016-01-01

    Aberrant T lymphocytes signaling is considered to play a crucial role in the abnormal immune state of primary immune thrombocytopenia (ITP). Lipid raft has been verified to engage in the T cell receptor (TCR)-mediated T lymphocytes signal transduction. Whether lipid raft-associated T cells signal transduction has impact on the pathogenesis of ITP is still unconfirmed. In this study, we aimed to reveal the abnormality in structure and function of lipid rafts (LRs) in CD4(+) and CD8(+) T lymphocytes of patients with ITP. Our results showed that there was an increased lipid raft aggregation in ITP patients, while this kind of increase would not be influenced by platelet counts or therapeutic regimes. Stimulation by anti-CD3/CD28 monoclonal antibodies promoted enhanced lipid raft clustering in T lymphocytes of ITP patients compared with negative controls. Methyl-β-cyclodextrin (MβCD) could block the abnormal lipid raft aggregation and disrupt the TCR-mediated T cells proliferation and cytokines secretion, including both proinflammatory cytokines and anti-inflammatory cytokines. The spontaneous activation of T lymphocytes from ITP patients might be due to the elevated co-localization of protein tyrosine phosphatase (PTP) CD45 and lipid rafts in patients' CD4(+) and CD8(+) T lymphocytes. These findings suggest that the autoactivation of T lymphocytes from ITP patients may lead to the abnormality in lipid raft structure and raft-anchored proteins, and the changes conversely promote the TCR-mediated T cells activation of ITP patients.

  17. Cytotoxic activity against human neuroblastoma and melanoma cells mediated by IgM antibodies derived from peripheral blood of healthy donors.

    PubMed

    Devarapu, Satish Kumar; Mamidi, Srinivas; Plöger, Frank; Dill, Othmar; Blixt, Ola; Kirschfink, Michael; Schwartz-Albiez, Reinhard

    2016-06-15

    A small percentage of healthy donors identified in the Western population carry antibodies in their peripheral blood which convey cytotoxic activity against certain human melanoma and neuroblastoma cell lines. We measured the cytotoxic activity of sera and plasmas from healthy donors on the human neuroblastoma cell line Kelly and various melanoma cell lines. Antibodies of IgM isotype, presumably belonging to the class of naturally occurring antibodies, exerted cytotoxic activity in a complement-dependent fashion. Apart from complement-dependent tumor cell lysis, we observed C3 opsonization in all tumor cell lines upon treatment with cytotoxic plasmas. Cell lines tested primarily expressed membrane complement regulatory proteins (mCRP) CD46, CD55 and CD59 to various extents. Blocking of mCRPs by monoclonal antibodies enhanced cell lysis and opsonization, though some melanoma cells remained resistant to complement attack. Epitopes recognized by cytotoxic antibodies were represented by gangliosides such as GD2 and GD3, as evidenced by cellular sialidase pretreatment and enhanced expression of distinct gangliosides. It remains to be clarified why only a small fraction of healthy persons carry these antitumor cytotoxic antibodies. PMID:26830059

  18. Cytotoxic activity against human neuroblastoma and melanoma cells mediated by IgM antibodies derived from peripheral blood of healthy donors.

    PubMed

    Devarapu, Satish Kumar; Mamidi, Srinivas; Plöger, Frank; Dill, Othmar; Blixt, Ola; Kirschfink, Michael; Schwartz-Albiez, Reinhard

    2016-06-15

    A small percentage of healthy donors identified in the Western population carry antibodies in their peripheral blood which convey cytotoxic activity against certain human melanoma and neuroblastoma cell lines. We measured the cytotoxic activity of sera and plasmas from healthy donors on the human neuroblastoma cell line Kelly and various melanoma cell lines. Antibodies of IgM isotype, presumably belonging to the class of naturally occurring antibodies, exerted cytotoxic activity in a complement-dependent fashion. Apart from complement-dependent tumor cell lysis, we observed C3 opsonization in all tumor cell lines upon treatment with cytotoxic plasmas. Cell lines tested primarily expressed membrane complement regulatory proteins (mCRP) CD46, CD55 and CD59 to various extents. Blocking of mCRPs by monoclonal antibodies enhanced cell lysis and opsonization, though some melanoma cells remained resistant to complement attack. Epitopes recognized by cytotoxic antibodies were represented by gangliosides such as GD2 and GD3, as evidenced by cellular sialidase pretreatment and enhanced expression of distinct gangliosides. It remains to be clarified why only a small fraction of healthy persons carry these antitumor cytotoxic antibodies.

  19. Potential to involve multiple effector cells with human recombinant interleukin-2 and antiganglioside monoclonal antibodies in a canine malignant melanoma immunotherapy model.

    PubMed

    Helfand, S C; Soergel, S A; Donner, R L; Gan, J; Hank, J A; Lindstrom, M J; Sondel, P M

    1994-10-01

    Human tumors originating from neuroectodermal cells such as malignant melanoma and neuroblastoma express high levels of disialogangliosides GD2 and GD3, making these antigens ideal for targeting by monoclonal antibodies (Mabs). The purpose of this study was to investigate expression and targeting of gangliosides on canine melanoma. Using immunohistochemical methods, we analyzed the expression of disialogangliosides GD2 and GD3 on canine oral malignant melanomas with murine Mabs 14.G2a and R24 that recognize GD2 and GD3 disialogangliosides, respectively, on human tumors. We also assessed the ability of Mab 14.G2a (and its mouse-human chimera, ch 14.18) to mediate antibody-dependent cellular cytotoxicity (ADCC) in vitro against a canine malignant melanoma cell line with human recombinant interleukin-2 (IL-2) activated canine peripheral blood lymphocytes (PBL), or canine neutrophil effector cells. Our data show that Mabs 14.G2a and R24 recognized fresh frozen canine oral melanoma. Mabs 14.G2a or ch 14.18, or IL-2, potentiated lysis of the canine malignant melanoma cell line by canine PBL. The killing effect observed using the combination of either Mab with IL-2 was additive. Mab 14.G2a mediated potent ADCC of canine melanoma by canine neutrophils. These studies indicate that disialogangliosides are expressed on fresh canine melanoma cells. Mabs reactive with these antigens can target and trigger tumor killing by multiple canine effector populations and IL-2 can potentiate these effects by canine lymphocytes. Thus, canine oral malignant melanoma, a spontaneously occurring, metastatic cancer in the dog, may be a relevant animal model to investigate combination immunotherapy using antitumor Mab and IL-2.

  20. Activation of cellular cytotoxicity and complement-mediated lysis of melanoma and neuroblastoma cells in vitro by murine antiganglioside antibodies MB 3.6 and 14.G2a.

    PubMed

    Mayer, P; Handgretinger, R; Bruchelt, G; Schaber, B; Rassner, G; Fierlbeck, G

    1994-04-01

    Mouse monoclonal antibodies against tumour-associated gangliosides GD2 (14.G2a) and GD3 (MB 3.6) were tested to mediate antibody-dependent cellular cytotoxicity (ADCC) with various effector cells or complement-dependent cytolysis (CDC). We also evaluated the immunomodulating potential of interferons in combination with cellular cytotoxicity. Using effector:target (E/T) ratios of 40:1, ADCC with effector cells such as granulocytes or mononuclear blood cells was not detectable against melanoma cell lines GR, SK-MEL-28 and G-361 which preferentially express GD3 and bind antibody MB 3.6. Neuroblastoma cell line SK-N-LO, which was used for comparative purposes, mainly expressed GD2 and the tumour cells were killed effectively after labelling with antibody 14.G2a. Granulocytes did not show significant killing of melanoma cells by ADCC, but neuroblastoma cells were killed very efficiently. Peripheral blood mononuclear cells (PBMC) also failed to kill melanoma cells. Interferon-beta slightly stimulated PBMC and increased killing of neuroblastoma cells, but no additive effects with ADCC were detectable. Incubation of target cells with interferons produced no significant differences in susceptibility of the target cells to interferon-activated PBMC cytotoxicity. Despite the lack of effectiveness in mediating cellular cytotoxicity, GD3 antibody MB 3.6 showed strong complement-dependent cytolysis in the presence of human plasma. There were remarkable differences in individual activity and different susceptibility of the melanoma cell lines. We assume that CDC may have more activity against melanoma cells than cytotoxicity associated with various effector cells.

  1. Passively Q-switched performance of a Nd:Gd3Ga5O12 eye-safe laser at 1423.4  nm with Co2+:LaMgAl11O19 as saturable absorber.

    PubMed

    Zhang, Huanian; Ma, Baomin; Chen, Xiaohan; Wang, Qingpu; Tao, Xutang; Li, Ping

    2013-12-10

    The performance of a LD-pumped passively Q-switched Nd:GGG eye-safe laser at 1423.4 nm with a Co(2+):LaMgAl(11)O(19) (Co:LMA) saturable absorber is demonstrated. A maximum average output power of 627 mW with an optical-to-optical efficiency of 3.35% and a slope efficiency of 5.1% was obtained under a pump power of 18.7 W. A minimum pulsewidth of 102 ns and a pulse repetition rate of 35 kHz were obtained with the T=1.0% output coupler. PMID:24513904

  2. Ganglioside GM1 Deficiency in Effector T Cells From NOD Mice Induces Resistance to Regulatory T-Cell Suppression

    PubMed Central

    Wu, Gusheng; Lu, Zi-Hua; Gabius, Hans-Joachim; Ledeen, Robert W.; Bleich, David

    2011-01-01

    OBJECTIVE To detect GM1 deficiency and determine its role in effector T cells (Teffs) from NOD mice in establishing resistance to regulatory T-cell (Treg) suppression. RESEARCH DESIGN AND METHODS CD4+ and CD8+ Teffs were isolated from spleens of prediabetic NOD mice for comparison with similar cells from Balb/c, C57BL/6, and NOR mice. GM1 was quantified with thin-layer chromatography for total cellular GM1 and flow cytometry for cell-surface GM1. Suppression of Teff proliferation was determined by application of GM1 cross-linking agents or coculturing with Tregs. Calcium influx in Teffs was quantified using fura-2. RESULTS Resting and activated CD4+ and CD8+ Teffs of NOD mice contained significantly less GM1 than Teffs from the other three mouse strains tested. After activation, NOD Teffs resisted suppression by Tregs or GM1 cross-linking agents in contrast to robust suppression of Balb/c Teffs; this was reversed by preincubation of NOD Teffs with GM1. NOD Teffs also showed attenuated Ca2+ influx via transient receptor potential channel 5 (TRPC5) channels induced by GM1 cross-linking, and this, too, was reversed by elevation of Teff GM1. CONCLUSIONS GM1 deficiency occurs in NOD Teffs and contributes importantly to failed suppression, which is rectified by increasing Teff GM1. Such elevation also reverses subthreshold Ca2+ influx via TRPC5 channels, an essential aspect of suppression. Our results also support a critical role for galectin-1 as a GM1 cross-linking counter-receptor that fittingly is upregulated and released by Tregs during activation. These findings suggest a novel mechanism by which pathogenic Teffs evade regulatory suppression, thereby leading to autoimmune β-cell destruction and type 1 diabetes. PMID:21788572

  3. How do membranes initiate Alzheimer's Disease? Formation of toxic amyloid fibrils by the amyloid β-protein on ganglioside clusters.

    PubMed

    Matsuzaki, Katsumi

    2014-08-19

    Alzheimer's disease (AD), a severe neurodegenerative disorder, causes more than half of dementia cases. According to the popular "Aβ hypothesis" to explain the mechanism of this disease, amyloid β-peptides (Aβ) of 39-43 amino acid residues aggregate and deposit onto neurons, igniting the neurotoxic cascade of the disease. Therefore, researchers studying AD would like to elucidate the mechanisms by which essentially water-soluble but hydrophobic Aβ aggregates under pathological conditions. Most researchers have investigated the aggregation of Aβ in aqueous solution, and they concluded that the final aggregation product, the amyloid fibrils, were less toxic than the component peptide oligomers. They consequently shifted their interests to more toxic "soluble oligomers", structures that form as intermediates or off-pathway products during the aggregation process. Some researchers have also investigated artificial oligomers prepared under nonphysiological conditions. In contrast to these "in solution" studies, we have focused on "membrane-mediated" amyloidogenesis. In an earlier study, other researchers identified a specific form of Aβ that was bound to monosialoganglioside GM1, a sugar lipid, in brains of patients who exhibited the early pathological changes associated with AD. This Account summarizes 15 years of our research on this topic. We have found that Aβ specifically binds to GM1 that occurs in clusters, but not when it is uniformly distributed. Clustering is facilitated by cholesterol. Upon binding, Aβ changes its conformation from a random coil to an α-helix-rich structure. A CH-π interaction between the aromatic side chains of Aβ and carbohydrate moieties appended to GM1 appears to be important for binding. In addition, as Aβ accumulates and reaches its first threshold concentration (Aβ/GM1 = ∼0.013), aggregated β-sheets of ∼15 molecules appear and coexist with the helical form. However, this β-structure is stable and does not form larger aggregates. When the disease progresses further and the Aβ/GM1 ratio exceeds ∼0.044, the β-structure converts to a second β-structure that can seed aggregates. The seed recruits monomers from the aqueous phase to form toxic amyloid fibrils that have larger surface hydrophobicity and can contain antiparallel β-sheets. In contrast, amyloid fibrils formed in aqueous solution are less toxic and have parallel β-sheets. The less polar environments of GM1 clusters play an important role in the formation of these toxic fibrils. Membranes that contain GM1 clusters not only accelerate the aggregation of Aβ by locally concentrating Aβ molecules but also generate amyloid fibrils with unique structures and significant cytotoxicity. The inhibition of this aggregation cascade could be a promising strategy for the development of AD-modulating therapies.

  4. Single chain FV constructs of anti-ganglioside GD2 antibodies for radioimaging and radioimmumotheraphy. Progress report

    SciTech Connect

    Cheung, N.K.V.; Larson, S.M.

    1993-11-01

    For the past several years, we have studied the anti-G{sub D2} murine monoclonal antibody, 3F8, in radiolabeled form, for diagnosis and therapy of neuroblastoma. The targeting properties of this antibody/antigen system are exceptional, with uptakes consistently in the highest range of reported results for in vivo human studies. The radioiodinated antibody 3F8 is now used by us as our criteria for diagnosis and staging of advanced neuroblastoma. This antibody is showing considerable promise also in our Phase I trials in Stage 4 neuroblastoma, and major responses are being seen at current dose level, with manageable marrow toxicity, but no limiting organ toxicity.

  5. A profile of sphingolipids and related compounds tentatively identified in yak milk.

    PubMed

    Qu, S; Barrett-Wilt, G; Fonseca, L M; Rankin, S A

    2016-07-01

    This work characterized a fraction of constituents in yak milk within the realm of approximately 1,000 to 3,000 Da using matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry. Eleven samples of yak milk powder from the Sichuan province of China were received by the Department of Food Science, University of Wisconsin-Madison, and stored at room temperature until analysis. Sample preparation involved delipidation and deproteinization of yak milk samples and cold ethanol precipitation. Subsequently, MALDI time-of-flight mass spectrometry was performed in positive ion, reflector mode (AB Sciex TOF/TOF 4800 MALDI; AB Sciex, Foster City, CA). The instrument was first calibrated with the manufacturer's 6-peptide mixture, and each spectrum was internally calibrated using the accurate mass of ACTH Fragment 18-39 standard peptide (protonated mass at m/z 2464.199) present in each sample. Laser power was adjusted for the calibration standards and for each sample so that the signal obtained for the most-abundant ion in each spectrum could be maximized, or kept below ~2×10(4) to preserve spectral quality. Structure and name based on mass were matched using the Metlin metabolite database (https://metlin.scripps.edu/index.php). Results of the current work for yak milk powder showed a large variety of sphingolipid structures with clusters around 1,200, 1,600, and 2,000 Da. The profiling matched several glycosphingolipids, such as gangliosides GA1, GD1a, GD1b, GD3, GM1, GM2, GM3, and GT2 and several other unique moieties, including deaminated neuraminic acid (KDN) oligosaccharides, and fucose containing gangliosides. Matrix preparation and MALDI time-of-flight parameters were important factors established in this work to allow high resolution profiling of complex sphingolipids in yak powder milk. PMID:27085416

  6. Small-molecule inhibitors of NMO-IgG binding to aquaporin-4 reduce astrocyte cytotoxicity in neuromyelitis optica

    PubMed Central

    Tradtrantip, Lukmanee; Zhang, Hua; Anderson, Marc O.; Saadoun, Samira; Phuan, Puay-Wah; Papadopoulos, Marios C.; Bennett, Jeffrey L.; Verkman, A. S.

    2012-01-01

    Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of spinal cord and optic nerve caused by pathogenic autoantibodies (NMO-IgG) against astrocyte aquaporin-4 (AQP4). We developed a high-throughput screen to identify blockers of NMO-IgG binding to human AQP4 using a human recombinant monoclonal NMO-IgG and transfected Fisher rat thyroid cells stably expressing human M23-AQP4. Screening of ∼60,000 compounds yielded the antiviral arbidol, the flavonoid tamarixetin, and several plant-derived berbamine alkaloids, each of which blocked NMO-IgG binding to AQP4 without affecting AQP4 expression, array assembly, or water permeability. The compounds inhibited NMO-IgG binding to AQP4 in NMO patient sera and blocked NMO-IgG-dependent complement- and cell-mediated cytotoxicity with IC50 down to ∼5 μM. Docking computations identified putative sites of blocker binding at the extracellular surface of AQP4. The blockers did not affect complement-dependent cytotoxicity caused by anti-GD3 antibody binding to ganglioside GD3. The blockers reduced by >80% the severity of NMO lesions in an ex vivo spinal cord slice culture model of NMO and in mice in vivo. Our results provide proof of concept for a small-molecule blocker strategy to reduce NMO pathology. Small-molecule blockers may also be useful for other autoimmune diseases caused by binding of pathogenic autoantibodies to defined targets.—Tradtrantip, L., Zhang, H., Anderson, M. O., Saadoun, S., Phuan, P.-W., Papadopoulos, M. C., Bennett, J. L., Verkman, A. S. Small-molecule inhibitors of NMO-IgG binding to aquaporin-4 reduce astrocyte cytotoxicity in neuromyelitis optica. PMID:22319008

  7. Glycosphingolipid synthesis inhibitor represses cytokine-induced activation of the Ras-MAPK pathway in embryonic neural precursor cells.

    PubMed

    Yanagisawa, Makoto; Nakamura, Kazuo; Taga, Tetsuya

    2005-09-01

    Neuronal and glial cells in the central nervous system are generated from common neural precursor cells during development. To evaluate the functions of glycosphingolipids (GSLs) in neural precursor cells, neuroepithelial cells (NECs) were prepared from mouse embryos (E14.5), and the effects of an inhibitor of glucosylceramide synthesis, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), on NECs was investigated. In PDMP-treated NECs, the expression of GD3, a major ganglioside of NECs, disappeared. We found that basic fibroblast growth factor (bFGF)-induced proliferation and extracellular signal-regulated kinase (ERK) activation were repressed in PDMP-treated NECs. Leukemia inhibitory factor (LIF)-induced ERK activation was also abolished in PDMP-treated NECs, suggesting that PDMP specifically represses the Ras-MAPK pathway. bFGF-induced activation of the Ras-MAPK pathway in NECs is dependent on GSL-enriched microdomains, lipid rafts. The organization of lipid rafts and the distribution of Ras and Grb2-SOS in the microdomains were not affected. However, Ras activation was repressed in PDMP-treated NECs. In PDMP-treated NECs, some neuronal genes were up-regulated and glial genes were down-regulated. These results suggest that GSLs might be involved in the proliferation, survival, signal transduction and differentiation of NECs.

  8. New anti-GD2 monoclonal antibodies produced from gamma-interferon-treated neuroblastoma cells.

    PubMed

    Gross, N; Beck, D; Portoukalian, J; Favre, S; Carrel, S

    1989-04-15

    Three monoclonal antibodies (IgG2) have been produced from hybridomas obtained by fusion of murine myeloma cells and spleen cells of mice hyperimmunized with gamma-interferon-treated neuroblastoma cells. The 3 MAbs, 7A4, 2A6 and IG8, detected an antigen present on neuroblastoma tumors and cell lines, but also on some neuro-ectoderm-derived tissues and cells. All 3 clones were shown to react with an epitope of the di-sialo-ganglioside GD2 molecules highly expressed by some neuro-ectoderm-derived tumors, mainly neuroblastoma. Whereas MAb IG8 specificity was restricted to GD2 and its o-acylated form, MAb 2A6 and 7A4 were also able to detect GD3 at high concentration of antibody as shown by TLC analysis and immunodetection. The 3 MAbs were able to lyse 100% neuroblastoma cells in the presence of rabbit or human complement. Direct binding assays with 125I-labelled MAbs showed that MAb 7A4 might be a good candidate for in vivo immunolocalization experiments. The high proportion of anti-GD2 MAbs obtained by our fusion and the increased binding of anti-GD2 MAbs on gamma-IFN-treated neuroblastoma cells suggests a modulation of the exposure and an increase in the immunogenicity of GD2 induced by gamma-IFN.

  9. Cell-surface antigens of melanoma recognized by human monoclonal antibodies.

    PubMed Central

    Yamaguchi, H; Furukawa, K; Fortunato, S R; Livingston, P O; Lloyd, K O; Oettgen, H F; Old, L J

    1987-01-01

    Human monoclonal antibodies (mAbs) were derived from lymph node lymphocytes and peripheral blood lymphocytes (PBL) from patients with melanoma. Four methods for generating human mAbs were compared: fusion with human [LICR-LON-HMy-2 (LICR-2)] or mouse (NS-1) cells; transformation by Epstein-Barr virus (EBV); and EBV transformation followed by NS-1 fusion. NS-1 fusion with lymph node lymphocytes resulted in a higher number of growing hybrids than LICR-2 fusion. Virtually no hybrids were obtained from NS-1 or LICR-2 fusions with PBL. EBV transformed lymphocytes from lymph node and peripheral blood with equal efficiency, and the yield of proliferating cultures for antibody screening was more than 10- to 30-fold greater than that obtained by fusion techniques. However, once antibody-producing cultures had been identified, stability and clonability of EBV-transformed cells were poorer than that of NS-1 hybrid cells. To combine the strengths of both methods, cultures of EBV-transformed cells were fused with NS-1; and hybrid clones were isolated that showed vigorous growth, clonability, and stable antibody secretion. Detailed specificity analysis of the mAbs produced by six of these clones indicated detection of a class 1 (unique) melanoma antigen, a class 3 melanoma antigen, and four ganglioside antigens (GD3, GM3, and two other, as yet uncharacterized, heterophile antigens). Images PMID:3031684

  10. Cancer Vaccines and Carbohydrate Epitopes

    PubMed Central

    Heimburg-Molinaro, Jamie; Lum, Michelle; Vijay, Geraldine; Jain, Miten; Almogren, Adel; Rittenhouse-Olson, Kate

    2011-01-01

    Tumor-associated carbohydrate antigens (TACA) result from the aberrant glycosylation that is seen with transformation to a tumor cell. The carbohydrate antigens that have been found to be tumor-associated include the mucin related Tn, Sialyl Tn, and Thomsen-Friedenreich antigens, the blood group Lewis related LewisY, Sialyl LewisX and Sialyl LewisA, and LewisX, (also known as stage-specific embryonic antigen-1, SSEA-1), the glycosphingolipids Globo H and stage-specific embryonic antigen-3 (SSEA-3), the sialic acid containing glycosphingolipids, the gangliosides GD2, GD3, GM2, fucosyl GM1, and Neu5GcGM3, and polysialic acid. Recent developments have furthered our understanding of the T-independent type II response that is seen in response to carbohydrate antigens. The selection of a vaccine target antigen is based on not only the presence of the antigen in a variety of tumor tissues but also on the role this antigen plays in tumor growth and metastasis. These roles for TACAs are being elucidated. Newly acquired knowledge in understanding the T-independent immune response and in understanding the key roles that carbohydrates play in metastasis are being applied in attempts to develop an effective vaccine response to TACAs. The role of each of the above mentioned carbohydrate antigens in cancer growth and metastasis and vaccine attempts using these antigens will be described. PMID:21964054

  11. Uptake and incorporation of an epitope-tagged sialic acid donor into intact rat liver Golgi compartments. Functional localization of sialyltransferase overlaps with beta-galactosyltransferase but not with sialic acid O-acetyltransferase.

    PubMed Central

    Chammas, R; McCaffery, J M; Klein, A; Ito, Y; Saucan, L; Palade, G; Farquhar, M G; Varki, A

    1996-01-01

    The transfer of sialic acids (Sia) from CMP-sialic acid (CMP-Sia) to N-linked sugar chains is thought to occur as a final step in their biosynthesis in the trans portion of the Golgi apparatus. In some cell types such Sia residues can have O-acetyl groups added to them. We demonstrate here that rat hepatocytes express 9-O-acetylated Sias mainly at the plasma membranes of both apical (bile canalicular) and basolateral (sinusoidal) domains. Golgi fractions also contain 9-O-acetylated Sias on similar N-linked glycoproteins, indicating that O-acetylation may take place in the Golgi. We show here that CMP-Sia-FITC (with a fluorescein group attached to the Sia) is taken up by isolated intact Golgi compartments. In these preparations, Sia-FITC is transferred to endogenous glycoprotein acceptors and can be immunochemically detected in situ. Addition of unlabeled UDP-Gal enhances Sia-FITC incorporation, indicating a substantial overlap of beta-galactosyltransferase and sialyltransferase machineries. Moreover, the same glycoproteins that incorporate Sia-FITC also accept [3H]galactose from the donor UDP-[3H]Gal. In contrast, we demonstrate with three different approaches (double-labeling, immunoelectron microscopy, and addition of a diffusible exogenous acceptor) that sialyltransferase and O-acetyltransferase machineries are much more separated from one another. Thus, 9-O-acetylation occurs after the last point of Sia addition in the trans-Golgi network. Indeed, we show that 9-O-acetylated sialoglycoproteins are preferentially segregated into a subset of vesicular carriers that concentrate membrane-bound, but not secretory, proteins. Images PMID:8930893

  12. Detection of neuroblastoma cells in CD34+ selected peripheral stem cells using a combination of tyrosine hydroxylase nested RT-PCR and anti-ganglioside GD2 immunocytochemistry.

    PubMed

    Lode, H N; Handgretinger, R; Schuermann, U; Seitz, G; Klingebiel, T; Niethammer, D; Beck, J

    1997-10-01

    A sensitive assay was developed for the detection of neuroblastoma cell contamination in CD34+ selected and unseparated peripheral blood stem cells (PBSC) used for autologous transplantation in stage 4 neuroblastoma patients. Specifically, we established a non-radioactive nested cDNA-PCR (nPCR) for detection of tyrosine hydroxylase (TH) gene expression combined with anti-disialoganglioside GD2 immunocytochemistry with the murine monoclonal antibody (MAb) 14G2a. Sensitivities of TH nPCR determined with a number of neuroblastoma cell lines and PBSCs correlated to cell line dependent basal TH gene expression levels and ranged from 1:10(4) to 1:10(6). The sensitivity obtained by immunocytochemistry was 1:10(5). We observed the highest PBSC contamination rate of 47% (18/38) among 38 PBSC specimens exclusively obtained from stage 4 neuroblastoma patients by using TH nPCR and GD2 immunocytochemistry in combination. Furthermore, a clinically applied purging method, CD34+ selection by immunoabsorption (CD34+ purity 42.4%), was used on 16 PBSCs. 10/16 (63%) preparations were contaminated prior to CD34+ selection and 56% (9/16) remained contaminated. A significant reduction of neuroblastoma cell contamination by CD34+ selection was not detectable, but the absolute amount of re-infused tumour cells was decreased due to 100-fold smaller cell counts of CD34+ selected grafts used for transplantation. 22 PBSC preparations were used for transplantation. A Kaplan-Meier analysis showed an event-free survival probability of 0.56 +/- 0.22 (n = 9) in the group with contaminated PBSCs versus 0.88 +/- 0.12 (n = 8) with no detectable neuroblastoma-cell contamination. Our data suggest that the combined use of TH nPCR and GD2 immunocytochemistry is optimal to detect contamination and monitor purging strategies. PMID:9516847

  13. LIGA20, a lyso derivative of ganglioside GM1, given orally after cortical thrombosis reduces infarct size and associated cognition deficit.

    PubMed Central

    Kharlamov, A; Zivkovic, I; Polo, A; Armstrong, D M; Costa, E; Guidotti, A

    1994-01-01

    A bilateral photochemically induced thrombotic lesion of rat sensorimotor cortex (approximately 3 mm in diameter and 25 mm3 in volume) is associated with a persistent cognition (learning and memory) deficit, which was evaluated with water maze tasks. The N-dichloroacetylsphingosine derivative of lysoGM1 (LIGA20) administered after the lesion either i.v. or per or reduces the infarct size by 30-40% and attenuates the associated cognition deficits, presumably by limiting the extent of damage of neurons at risk located in the surroundings of the infarcted core (i.e., area penumbra). The LIGA20 protection is dose and time dependent. Maximal protection is afforded by a single dose of LIGA20 of 34 mumol/kg i.v. 1 hr after lesion or by a dose of 270 mumol/kg per os when administered 1 hr and 24 hr after the lesion. The protective effect of LIGA20 can be observed when the drug is administered i.v. up to 6 hr after the lesion. The protective efficacy of the oral administration of LIGA20 is related to its physiochemical properties, which, unlike those of GM1, allow absorption from the gastrointestinal tract. LIGA20 given orally reaches the brain promptly and rapidly inserts into the neuronal membranes. Here, by an unknown molecular mechanism, LIGA20 selectively reduces the pathological amplification of Ca2+ signaling elicited by persistent stimulation of ionotropic glutamate receptors in the area penumbra. PMID:8022776

  14. Defective macroautophagic turnover of brain lipids in the TgCRND8 Alzheimer mouse model: prevention by correcting lysosomal proteolytic deficits.

    PubMed

    Yang, Dun-Sheng; Stavrides, Philip; Saito, Mitsuo; Kumar, Asok; Rodriguez-Navarro, Jose A; Pawlik, Monika; Huo, Chunfeng; Walkley, Steven U; Saito, Mariko; Cuervo, Ana M; Nixon, Ralph A

    2014-12-01

    Autophagy, the major lysosomal pathway for the turnover of intracellular organelles is markedly impaired in neurons in Alzheimer's disease and Alzheimer mouse models. We have previously reported that severe lysosomal and amyloid neuropathology and associated cognitive deficits in the TgCRND8 Alzheimer mouse model can be ameliorated by restoring lysosomal proteolytic capacity and autophagy flux via genetic deletion of the lysosomal protease inhibitor, cystatin B. Here we present evidence that macroautophagy is a significant pathway for lipid turnover, which is defective in TgCRND8 brain where lipids accumulate as membranous structures and lipid droplets within giant neuronal autolysosomes. Levels of multiple lipid species including several sphingolipids (ceramide, ganglioside GM3, GM2, GM1, GD3 and GD1a), cardiolipin, cholesterol and cholesteryl esters are elevated in autophagic vacuole fractions and lysosomes isolated from TgCRND8 brain. Lipids are localized in autophagosomes and autolysosomes by double immunofluorescence analyses in wild-type mice and colocalization is increased in TgCRND8 mice where abnormally abundant GM2 ganglioside-positive granules are detected in neuronal lysosomes. Cystatin B deletion in TgCRND8 significantly reduces the number of GM2-positive granules and lowers the levels of GM2 and GM3 in lysosomes, decreases lipofuscin-related autofluorescence, and eliminates giant lipid-containing autolysosomes while increasing numbers of normal-sized autolysosomes/lysosomes with reduced content of undigested components. These findings have identified macroautophagy as a previously unappreciated route for delivering membrane lipids to lysosomes for turnover, a function that has so far been considered to be mediated exclusively through the endocytic pathway, and revealed that autophagic-lysosomal dysfunction in TgCRND8 brain impedes lysosomal turnover of lipids as well as proteins. The amelioration of lipid accumulation in TgCRND8 by removing cystatin B

  15. Accelerated Tumor Growth Mediated by Sub-lytic Levels of Antibody-Induced Complement Activation is Associated with Activation of the PI3K/AKT Survival Pathway

    PubMed Central

    Wu, Xiaohong; Ragupathi, Govind; Panageas, Katherine; Hong, Feng; Livingston, Philip O.

    2013-01-01

    Purpose We addressed the possibility that low levels of tumor cell bound antibodies targeting gangliosides might accelerate tumor growth. Experimental Design To test this hypothesis, we treated mice with a range of mAb doses against GM2, GD2, GD3 and CD20 after challenge with tumors expressing these antigens and tested the activity of the same mAbs in-vitro. We also explored the mechanisms behind the complement-mediated tumor growth acceleration that we observed and an approach to overcome it. Results Serologically detectable levels of IgM-mAb against GM2 are able to delay or prevent tumor growth of high GM2-expressing cell lines both in-vitro and in a SCID mouse model, while very low levels of this mAb resulted in slight but consistent acceleration of tumor growth in both settings. Surprisingly, this is not restricted to IgM antibodies targeting GM2 but consistent against IgG-mAb targeting GD3 as well. These findings were mirrored by in-vitro studies with antibodies against these antigens as well as GD2 and CD20 (with Rituxan), and shown to be complement-dependent in all cases. Complement-mediated accelerated growth of cultured tumor cell lines initiated by low mAb levels was associated with activation of the PI3K/AKT survival pathway and significantly elevated levels of both p-AKT and p-PRAS40. This complement-mediated PI3K-activation and accelerated tumor growth in-vitro and in-vivo are eliminated by PI3K-inhibitors NVP-BEZ235 and Wortmannin. These PI3K-inhibitors also significantly increased efficacy of high doses of these 4 mAbs. Conclusion Our findings suggest that manipulation of the PI3K/AKT pathway and its signaling network can significantly increase the potency of passively administered mAbs and vaccine-induced-antibodies targeting a variety of tumor-cell-surface-antigens. PMID:23833306

  16. Immune response to racotumomab in a child with relapsed neuroblastoma.

    PubMed

    Sampor, C; Guthmann, M D; Scursoni, A; Cacciavillano, W; Torbidoni, A; Galluzzo, L; Camarero, S; Lopez, J; de Dávila, M T G; Fainboim, L; Chantada, G L

    2012-01-01

    Immunotherapy targeting ganglioside antigens is a powerful tool for the treatment of high risk neuroblastoma. However, only treatment with anti-GD2 antibodies has been used in clinical practice and other options may be pursued. We report the use of racotumomab, an anti-idiotype vaccine against N-glycolyl neuraminic acid (NeuGc)- containing gangliosides, eliciting an immune response in a child with relapsed neuroblastoma expressing the NeuGcGM3 ganglioside.

  17. Cancer stem cells in the mammalian central nervous system.

    PubMed

    Pilkington, G J

    2005-12-01

    proliferation and migration in developing neural tumour cells may exist between NG2 and ganglioside GD3. The divergent pathways of differentiation of CNS tumours and the possibility of stem cell origin, for some, if not all, such neoplasms remain a matter for debate and continued research, but the presence of self-renewing neural stem cells in the CNS of both children and adults strongly suggests a role for these cells in tumour initiation and resistance to current therapeutic strategies.

  18. A case of severe chronic inflammatory demyelinating polyradiculoneuropathy with monoclonal gammopathy of undetermined significance with alternating immunoglobulin class to IgM from IgA.

    PubMed

    Hayashi, Shintaro; Nagamine, Shun; Makioka, Kouki; Kusunoki, Susumu; Okamoto, Koichi

    2016-09-29

    A 71-year-old woman with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with IgA-λ monoclonal gammopathy of undetermined significance (MGUS) showed the acute development of tetraplegia, respiratory failure, and a marked fluctuation of the blood pressure. Intravenous (IV) high-dose steroid therapy (methylprednisolone: 1 g/day × 3 days), followed by oral prednisolone (PSL) (40 mg/day), and IV immunoglobulin (IVIg, 0.4 g/kg/day × 5 days) administrations resulted in the amelioration of these symptoms. However, they soon relapsed, which eventually led to complete tetraplegia and the need for mechanical ventilation. At this time, serum components of IgA-λ and IgM-λ were biclonally positive. Seven courses of plasma exchange and the alternative administration of dexamethasone (12 mg/day) and methtorexate (15 mg/week) were conducted, but with no significant improvement. Nine months after admission, she showed totally-locked in syndrome. Cryo-preserved serum obtained at this time showed high titers of IgM class antibodies against ganglioside (GD3 +++, GT1a ++++, GT1b ++, GQ1b +++, and GD1b +++), which had been negative on admission. Biopsy of the left sural nerve showed moderate reductions of large and small myelinated fibers with no inflammation, no depositions of amyloid, IgG, IgA, or IgM, and teased fiber findings revealed neither myelin ovoids nor segmental demyelination. Alternatively, melphalan at 5 mg and PSL at 32 mg were administered, with no amelioration, while serum IgA-λ monoclonal protein diminished, and IgM-λ M protein positivity was continuously observed. She frequently developed sepsis; therefore, we could no longer continue any immunosupressive therapies, but monthly IVIg administrations were given. Twelve months after admission, her neurological symptoms gradually improved and she was weaned off of mechanical ventilation. Eighteen months after admission, her muscle strength corresponded to 2 on manual muscle testing

  19. A case of severe chronic inflammatory demyelinating polyradiculoneuropathy with monoclonal gammopathy of undetermined significance with alternating immunoglobulin class to IgM from IgA.

    PubMed

    Hayashi, Shintaro; Nagamine, Shun; Makioka, Kouki; Kusunoki, Susumu; Okamoto, Koichi

    2016-09-29

    A 71-year-old woman with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with IgA-λ monoclonal gammopathy of undetermined significance (MGUS) showed the acute development of tetraplegia, respiratory failure, and a marked fluctuation of the blood pressure. Intravenous (IV) high-dose steroid therapy (methylprednisolone: 1 g/day × 3 days), followed by oral prednisolone (PSL) (40 mg/day), and IV immunoglobulin (IVIg, 0.4 g/kg/day × 5 days) administrations resulted in the amelioration of these symptoms. However, they soon relapsed, which eventually led to complete tetraplegia and the need for mechanical ventilation. At this time, serum components of IgA-λ and IgM-λ were biclonally positive. Seven courses of plasma exchange and the alternative administration of dexamethasone (12 mg/day) and methtorexate (15 mg/week) were conducted, but with no significant improvement. Nine months after admission, she showed totally-locked in syndrome. Cryo-preserved serum obtained at this time showed high titers of IgM class antibodies against ganglioside (GD3 +++, GT1a ++++, GT1b ++, GQ1b +++, and GD1b +++), which had been negative on admission. Biopsy of the left sural nerve showed moderate reductions of large and small myelinated fibers with no inflammation, no depositions of amyloid, IgG, IgA, or IgM, and teased fiber findings revealed neither myelin ovoids nor segmental demyelination. Alternatively, melphalan at 5 mg and PSL at 32 mg were administered, with no amelioration, while serum IgA-λ monoclonal protein diminished, and IgM-λ M protein positivity was continuously observed. She frequently developed sepsis; therefore, we could no longer continue any immunosupressive therapies, but monthly IVIg administrations were given. Twelve months after admission, her neurological symptoms gradually improved and she was weaned off of mechanical ventilation. Eighteen months after admission, her muscle strength corresponded to 2 on manual muscle testing

  20. Glycosylation of erythrocyte spectrin and its modification in visceral leishmaniasis.

    PubMed

    Samanta, Sajal; Dutta, Devawati; Ghoshal, Angana; Mukhopadhyay, Sumi; Saha, Bibhuti; Sundar, Shyam; Jarmalavicius, Saulius; Forgber, Michael; Mandal, Chhabinath; Walden, Peter; Mandal, Chitra

    2011-01-01

    Using a lectin, Achatinin-H, having preferential specificity for glycoproteins with terminal 9-O-acetyl sialic acid derivatives linked in α2-6 linkages to subterminal N-acetylgalactosamine, eight distinct disease-associated 9-O-acetylated sialoglycoproteins was purified from erythrocytes of visceral leishmaniaisis (VL) patients (RBC(VL)). Analyses of tryptic fragments by mass spectrometry led to the identification of two high-molecular weight 9-O-acetylated sialoglycoproteins as human erythrocytic α- and β-spectrin. Total spectrin purified from erythrocytes of VL patients (spectrin(VL)) was reactive with Achatinin-H. Interestingly, along with two high molecular weight bands corresponding to α- and β-spectrin another low molecular weight 60 kDa band was observed. Total spectrin was also purified from normal human erythrocytes (spectrin(N)) and insignificant binding with Achatinin-H was demonstrated. Additionally, this 60 kDa fragment was totally absent in spectrin(N). Although the presence of both N- and O-glycosylations was found both in spectrin(N) and spectrin(VL), enhanced sialylation was predominantly induced in spectrin(VL). Sialic acids accounted for approximately 1.25 kDa mass of the 60 kDa polypeptide. The demonstration of a few identified sialylated tryptic fragments of α- and β-spectrin(VL) confirmed the presence of terminal sialic acids. Molecular modelling studies of spectrin suggest that a sugar moiety can fit into the potential glycosylation sites. Interestingly, highly sialylated spectrin(VL) showed decreased binding with spectrin-depleted inside-out membrane vesicles of normal erythrocytes compared to spectrin(N) suggesting functional abnormality. Taken together this is the first report of glycosylated eythrocytic spectrin in normal erythrocytes and its enhanced sialylation in RBC(VL). The enhanced sialylation of this cytoskeleton protein is possibly related to the fragmentation of spectrin(VL) as evidenced by the presence of an additional 60

  1. Glycosylation of Erythrocyte Spectrin and Its Modification in Visceral Leishmaniasis

    PubMed Central

    Samanta, Sajal; Dutta, Devawati; Ghoshal, Angana; Mukhopadhyay, Sumi; Saha, Bibhuti; Sundar, Shyam; Jarmalavicius, Saulius; Forgber, Michael; Mandal, Chhabinath; Walden, Peter; Mandal, Chitra

    2011-01-01

    Using a lectin, Achatinin-H, having preferential specificity for glycoproteins with terminal 9-O-acetyl sialic acid derivatives linked in α2-6 linkages to subterminal N-acetylgalactosamine, eight distinct disease-associated 9-O-acetylated sialoglycoproteins was purified from erythrocytes of visceral leishmaniaisis (VL) patients (RBCVL). Analyses of tryptic fragments by mass spectrometry led to the identification of two high-molecular weight 9-O-acetylated sialoglycoproteins as human erythrocytic α- and β-spectrin. Total spectrin purified from erythrocytes of VL patients (spectrinVL) was reactive with Achatinin-H. Interestingly, along with two high molecular weight bands corresponding to α- and β-spectrin another low molecular weight 60 kDa band was observed. Total spectrin was also purified from normal human erythrocytes (spectrinN) and insignificant binding with Achatinin-H was demonstrated. Additionally, this 60 kDa fragment was totally absent in spectrinN. Although the presence of both N- and O-glycosylations was found both in spectrinN and spectrinVL, enhanced sialylation was predominantly induced in spectrinVL. Sialic acids accounted for approximately 1.25 kDa mass of the 60 kDa polypeptide. The demonstration of a few identified sialylated tryptic fragments of α- and β-spectrinVL confirmed the presence of terminal sialic acids. Molecular modelling studies of spectrin suggest that a sugar moiety can fit into the potential glycosylation sites. Interestingly, highly sialylated spectrinVL showed decreased binding with spectrin-depleted inside-out membrane vesicles of normal erythrocytes compared to spectrinN suggesting functional abnormality. Taken together this is the first report of glycosylated eythrocytic spectrin in normal erythrocytes and its enhanced sialylation in RBCVL. The enhanced sialylation of this cytoskeleton protein is possibly related to the fragmentation of spectrinVL as evidenced by the presence of an additional 60 kDa fragment, absent in

  2. Advanced Technologies in Sialic Acid and Sialoglycoconjugate Analysis.

    PubMed

    Kitajima, Ken; Varki, Nissi; Sato, Chihiro

    2015-01-01

    Although the structural diversity of sialic acid (Sia) is rapidly expanding, understanding of its biological significance has lagged behind. Advanced technologies to detect and probe diverse structures of Sia are absolutely necessary not only to understand further biological significance but also to pursue medicinal and industrial applications. Here we describe analytical methods for detection of Sia that have recently been developed or improved, with a special focus on 9-O-acetylated N-acetylneuraminic acid (Neu5,9Ac), N-glycolylneuraminic acid (Neu5Gc), deaminoneuraminic acid (Kdn), O-sulfated Sia (SiaS), and di-, oligo-, and polysialic acid (diSia/oligoSia/polySia) in glycoproteins and glycolipids. Much more attention has been paid to these Sia and sialoglycoconjugates during the last decade, in terms of regulation of the immune system, neural development and function, tumorigenesis, and aging.

  3. An Open Receptor-Binding Cavity of Hemagglutinin-Esterase-Fusion Glycoprotein from Newly-Identified Influenza D Virus: Basis for Its Broad Cell Tropism

    PubMed Central

    Song, Hao; Qi, Jianxun; Khedri, Zahra; Diaz, Sandra; Yu, Hai; Chen, Xi; Varki, Ajit; Shi, Yi; Gao, George F.

    2016-01-01

    Influenza viruses cause seasonal flu each year and pandemics or epidemic sporadically, posing a major threat to public health. Recently, a new influenza D virus (IDV) was isolated from pigs and cattle. Here, we reveal that the IDV utilizes 9-O-acetylated sialic acids as its receptor for virus entry. Then, we determined the crystal structures of hemagglutinin-esterase-fusion glycoprotein (HEF) of IDV both in its free form and in complex with the receptor and enzymatic substrate analogs. The IDV HEF shows an extremely similar structural fold as the human-infecting influenza C virus (ICV) HEF. However, IDV HEF has an open receptor-binding cavity to accommodate diverse extended glycan moieties. This structural difference provides an explanation for the phenomenon that the IDV has a broad cell tropism. As IDV HEF is structurally and functionally similar to ICV HEF, our findings highlight the potential threat of the virus to public health. PMID:26816272

  4. An Open Receptor-Binding Cavity of Hemagglutinin-Esterase-Fusion Glycoprotein from Newly-Identified Influenza D Virus: Basis for Its Broad Cell Tropism.

    PubMed

    Song, Hao; Qi, Jianxun; Khedri, Zahra; Diaz, Sandra; Yu, Hai; Chen, Xi; Varki, Ajit; Shi, Yi; Gao, George F

    2016-01-01

    Influenza viruses cause seasonal flu each year and pandemics or epidemic sporadically, posing a major threat to public health. Recently, a new influenza D virus (IDV) was isolated from pigs and cattle. Here, we reveal that the IDV utilizes 9-O-acetylated sialic acids as its receptor for virus entry. Then, we determined the crystal structures of hemagglutinin-esterase-fusion glycoprotein (HEF) of IDV both in its free form and in complex with the receptor and enzymatic substrate analogs. The IDV HEF shows an extremely similar structural fold as the human-infecting influenza C virus (ICV) HEF. However, IDV HEF has an open receptor-binding cavity to accommodate diverse extended glycan moieties. This structural difference provides an explanation for the phenomenon that the IDV has a broad cell tropism. As IDV HEF is structurally and functionally similar to ICV HEF, our findings highlight the potential threat of the virus to public health. PMID:26816272

  5. Detection and characterization of a sialoglycosylated bacterial ABC-type phosphate transporter protein from patients with visceral leishmaniasis.

    PubMed

    Ghoshal, Angana; Mukhopadhyay, Sumi; Demine, Rodion; Forgber, Michael; Jarmalavicius, Saulius; Saha, Bibhuti; Sundar, Shyam; Walden, Peter; Mandal, Chhabinath; Mandal, Chitra

    2009-08-01

    We report the discovery and characterization of a glycosylated bacterial ABC-type phosphate transporter isolated from the peripheral blood mononuclear cell (PBMC) fraction of patients with visceral leishmaniasis (VL). Three disease-associated 9-O-acetylated sialoglycoproteins (9-O-AcSGPs) of 19, 56 and 65 kDa, respectively, had been identified and their purity, apparent mass and pI established by SDS-PAGE and isoelectric focusing. Western blot analyses showed that the 9-O-acetylated sialic acid is linked via alpha2-->6 linkage to a subterminal N-acetylgalactosamine. For the 56 kDa protein, N- as well as O-glycosylations were demonstrated by specific glycosidase treatment and found to account for more than 9 kDa of the protein mass. The presence of sialic acids was further confirmed through thin layer chromatography, fluorimetric HPLC and electrospray ionization-mass spectrometry. The protein was identified by mass spectrometry and de novo sequencing of five tryptic fragments as a periplasmic ABC-type phosphate transporter of Pseudomonas aeruginosa. The amino acid sequences of the assigned peptides had 83-100% identity with the NCBI entry for a Pseudomonas transporter protein. Based on the recently reported X-ray structure of a human phosphate-binding protein, we predicted a 3D structural model for the 56 kDa protein using homology and threading methods. The most probable N- and O-glycosylation sites were identified by combinations of sequence motif-searching bioinformatics tools, solvent accessibility calculations, structural environment analyses and mass spectrometric data. This is the first reported glycosylation as well as sialylation of the periplasmic component of an ABC-type phosphate transporter protein and of one of few identified bacterial glycoproteins.

  6. Dysregulated Expression of Glycolipids in Tumor Cells: From Negative Modulator of Anti-tumor Immunity to Promising Targets for Developing Therapeutic Agents

    PubMed Central

    Daniotti, Jose Luis; Lardone, Ricardo D.; Vilcaes, Aldo A.

    2016-01-01

    Glycolipids are complex molecules consisting of a ceramide lipid moiety linked to a glycan chain of variable length and structure. Among these are found the gangliosides, which are sialylated glycolipids ubiquitously distributed on the outer layer of vertebrate plasma membranes. Changes in the expression of certain species of gangliosides have been described to occur during cell proliferation, differentiation, and ontogenesis. However, the aberrant and elevated expression of gangliosides has been also observed in different types of cancer cells, thereby promoting tumor survival. Moreover, gangliosides are actively released from the membrane of tumor cells, having a strong impact on impairing anti-tumor immunity. Beyond the undesirable effects of gangliosides in cancer cells, a substantial number of cancer immunotherapies have been developed in recent years that have used gangliosides as the main target. This has resulted in successful immune cell- or antibody-responses against glycolipids, with promising results having been obtained in clinical trials. In this review, we provide a general overview on the metabolism of glycolipids, both in normal and tumor cells, as well as examining glycolipid-mediated immune modulation and the main successes achieved in immunotherapies using gangliosides as molecular targets. PMID:26779443

  7. Magnetic Endohedral Metallofullerenes with Floppy Interiors

    NASA Astrophysics Data System (ADS)

    Qian, Meichun; Khanna, Shiv; Knickelbein, Mark

    2007-03-01

    Investigations on the electronic structure and magnetic properties of a free Gd3N and Gd3N@C80 have been carried out using to examine the stability and the electronic and magnetic properties of the endohedral species. Using a synergistic approach combining Stern-Gerlach experiments in beams and first principles electronic structure studies, it is demonstrated that an isolated Gd3N has a ground state spin moment of 23 μB followed by a non-collinear state of 17.2 μB only 88 meV above the ground state. The large moment is largely due to localized f-electrons. As a Gd3N is embedded inside a C80 cage, the localized f-electrons maintain the magnetic character while the hybridization between the s,d states of isolated Gd3N and p-states of C80 leads to a strongly bound motif with an interaction energy of 13.63 eV and a large HOMO-LUMO gap of 1.48 eV. Gd3N@C80 is further shown to possess two isomers corresponding to the location of the N atom on either side of the Gd3 triangle with an appreciable electric dipole moment and a low barrier of 91 meV for transition between them offering potential for a fluctuating dipole.

  8. Ion Insertion on the Crystal Structure, Photoluminescence, and Dielectric Properties of o-Mullite Nanoparticles

    NASA Astrophysics Data System (ADS)

    Sanad, M. M. S.; Rashad, M. M.; Abdel-Aal, E. A.; El-Shahat, M. F.; Powers, K.

    2014-09-01

    Nanocrystalline Gd3+-doped Gd x Al6- x Si2O13 mullite powders with x from 0.005 to 0.025 have been synthesized via a facile coprecipitation technique. X-ray diffraction results revealed that o-mullite was detected as the major phase for x = 0.0 to 0.01, whereas corundum α-Al2O3 was predominant for x = 0.025. It was found that the volume of the mullite unit cell increased with Gd3+ ion incorporation. Differential scanning calorimetry thermograms evinced that the exothermic peak temperature of mullite shifted to lower values with Gd3+ ion insertion. Transmission electron microscopy observations of pure mullite nanoparticles displayed orthorhombic-like shapes. Meanwhile, at 0.5% Gd3+ ion content, the mullite particles exhibited platelet-like shapes, which distorted into spheroidal-like crystals at high Gd3+ ion contents (1% and 2.5%). The photoluminescence spectra indicated that the intensity of the emission spectra improved considerably with Gd3+ ion doping. On the other hand, dielectric measurements of sintered samples showed that the maximum dielectric loss values were 1.7 and 1.4 at 1.5 MHz and 1.5 GHz, respectively, with 2.5% Gd3+ ion content.

  9. Mitochondrial dysfunction induced by different concentrations of gadolinium ion.

    PubMed

    Zhao, Jie; Zhou, Zhi-Qiang; Jin, Jian-Cheng; Yuan, Lian; He, Huan; Jiang, Feng-Lei; Yang, Xiao-Gang; Dai, Jie; Liu, Yi

    2014-04-01

    Gadolinium-based compounds are the most widely used paramagnetic contrast agents in magnetic resonance imaging on the world. But the tricationic gadolinium ion (Gd(3+)) could induce cell apoptosis probably because of its effects on mitochondria. Until now, the mechanism about how Gd(3+) interacts with mitochondria is not well elucidated. In this work, mitochondrial swelling, collapsed transmembrane potential and decreased membrane fluidity were observed to be important factors for mitochondrial permeability transition pore (mtPTP) opening induced by Gd(3+). The protection effect of CsA (Cyclosporin A) could confirm high concentration of Gd(3+) (500 μM) would trigger mtPTP opening. Moreover, mitochondrial outer membrane breakdown and volume expansion observed clearly by transmission electron microscopy and the release of Cyt c (Cytochrome c) could explain the mtPTP opening from another aspect. In addition, MBM(+) (monobromobimane(+)) and DTT (dithiothreitol) could protect thiol (-SH) groups from oxidation so that the toxicity of Gd(3+) might be resulted from the chelation of -SH of membrane proteins by free Gd(3+). Gd(3+) could inhibit the initiation of mitochondrial membrane lipid peroxidation, so it might interact with anionic lipids too. These findings will highly contribute to the safe applications of Gd-based agents.

  10. Gadolinium-hydrogen ion exchange of zirconium phosphate

    NASA Technical Reports Server (NTRS)

    Liu, D. C.; Power, J. L.

    1972-01-01

    The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

  11. Novel insights into the lipidome of glioblastoma cells based on a combined PLSR and DD-HDS computational analysis

    NASA Astrophysics Data System (ADS)

    Lespinats, S.; Meyer-Bäse, Anke; He, Huan; Marshall, Alan G.; Conrad, Charles A.; Emmett, Mark R.

    2009-05-01

    Partial Least Square Regression (PLSR) and Data-Driven High Dimensional Scaling (DD-HDS) are employed for the prediction and the visualization of changes in polar lipid expression induced by different combinations of wild-type (wt) p53 gene therapy and SN38 chemotherapy of U87 MG glioblastoma cells. A very detailed analysis of the gangliosides reveals that certain gangliosides of GM3 or GD1-type have unique properties not shared by the others. In summary, this preliminary work shows that data mining techniques are able to determine the modulation of gangliosides by different treatment combinations.

  12. Neuronal Expression of Glucosylceramide Synthase in Central Nervous System Regulates Body Weight and Energy Homeostasis

    PubMed Central

    Nordström, Viola; Willershäuser, Monja; Herzer, Silke; Rozman, Jan; von Bohlen und Halbach, Oliver; Meldner, Sascha; Rothermel, Ulrike; Kaden, Sylvia; Roth, Fabian C.; Waldeck, Clemens; Gretz, Norbert; de Angelis, Martin Hrabě; Draguhn, Andreas; Klingenspor, Martin

    2013-01-01

    Hypothalamic neurons are main regulators of energy homeostasis. Neuronal function essentially depends on plasma membrane-located gangliosides. The present work demonstrates that hypothalamic integration of metabolic signals requires neuronal expression of glucosylceramide synthase (GCS; UDP-glucose:ceramide glucosyltransferase). As a major mechanism of central nervous system (CNS) metabolic control, we demonstrate that GCS-derived gangliosides interacting with leptin receptors (ObR) in the neuronal membrane modulate leptin-stimulated formation of signaling metabolites in hypothalamic neurons. Furthermore, ganglioside-depleted hypothalamic neurons fail to adapt their activity (c-Fos) in response to alterations in peripheral energy signals. Consequently, mice with inducible forebrain neuron-specific deletion of the UDP-glucose:ceramide glucosyltransferase gene (Ugcg) display obesity, hypothermia, and lower sympathetic activity. Recombinant adeno-associated virus (rAAV)-mediated Ugcg delivery to the arcuate nucleus (Arc) significantly ameliorated obesity, specifying gangliosides as seminal components for hypothalamic regulation of body energy homeostasis. PMID:23554574

  13. Antiganglioside antibodies and their pathophysiological effects on Guillain–Barré syndrome and related disorders—A review

    PubMed Central

    Kaida, Kenichi; Ariga, Toshio; Yu, Robert K

    2009-01-01

    Guillain–Barré syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy which can cause acute quadriplegia. Infection with micro-organisms, including Campylobacter jejuni (C. jejuni), Haemophilus influenzae, and Cytomegalovirus (CMV), is recognized as a main triggering event for the disease. Lipooligosaccharide (LOS) genes are responsible for the formation of human ganglioside-like LOS structures in infectious micro-organisms that can induce GBS. Molecular mimicry of LOSs on the surface of infectious agents and of ganglioside antigens on neural cells is thought to induce cross-reactive humoral and cellular immune responses. Patients with GBS develop antibodies against those gangliosides, resulting in autoimmune targeting of peripheral nerve sites, leading to neural damage. Heterogeneity of ganglioside expression in the peripheral nervous system (PNS) may underlie the differential clinical manifestation of the GBS variants. Recent studies demonstrate that some GBS sera react with ganglioside complexes consisting of two different gangliosides, such as GD1a and GD1b, or GM1 and GD1a, but not with each constituent ganglioside alone. The discovery of antiganglioside complex antibodies not only improves the detection rate of autoantibodies in GBS, but also provides a new concept in the antibody–antigen interaction through clustered carbohydrate epitopes. Although ganglioside mimicry is one of the possible etiological causes of GBS, unidentified factors may also contribute to the pathogenesis of GBS. While GBS is not considered a genetic disease, host factors, particularly human lymphocyte antigen type, appear to have a role in the pathogenesis of GBS following C. jejuni infection. PMID:19240270

  14. PCR-Restriction Fragment Length Polymorphism Analysis of Campylobacter jejuni Genes Involved in Lipooligosaccharide Biosynthesis Identifies Putative Molecular Markers for Guillain-Barré Syndrome▿

    PubMed Central

    Godschalk, Peggy C. R.; van Belkum, Alex; van den Braak, Nicole; van Netten, Diana; Ang, C. Wim; Jacobs, Bart C.; Gilbert, Michel; Endtz, Hubert P.

    2007-01-01

    Molecular mimicry of Campylobacter jejuni lipooligosaccharides (LOS) by gangliosides in peripheral nerve tissue probably triggers the Guillain-Barré syndrome due to the induction of cross-reactive antibodies. PCR-restriction fragment length polymorphism analysis of C. jejuni genes involved in the biosynthesis of LOS demonstrated that specific genes were associated with the expression of ganglioside mimics and the development of neuropathy. PMID:17507514

  15. Antiganglioside antibodies and their pathophysiological effects on Guillain-Barré syndrome and related disorders--a review.

    PubMed

    Kaida, Kenichi; Ariga, Toshio; Yu, Robert K

    2009-07-01

    Guillain-Barré syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy which can cause acute quadriplegia. Infection with micro-organisms, including Campylobacter jejuni (C. jejuni), Haemophilus influenzae, and Cytomegalovirus (CMV), is recognized as a main triggering event for the disease. Lipooligosaccharide (LOS) genes are responsible for the formation of human ganglioside-like LOS structures in infectious micro-organisms that can induce GBS. Molecular mimicry of LOSs on the surface of infectious agents and of ganglioside antigens on neural cells is thought to induce cross-reactive humoral and cellular immune responses. Patients with GBS develop antibodies against those gangliosides, resulting in autoimmune targeting of peripheral nerve sites, leading to neural damage. Heterogeneity of ganglioside expression in the peripheral nervous system (PNS) may underlie the differential clinical manifestation of the GBS variants. Recent studies demonstrate that some GBS sera react with ganglioside complexes consisting of two different gangliosides, such as GD1a and GD1b, or GM1 and GD1a, but not with each constituent ganglioside alone. The discovery of antiganglioside complex antibodies not only improves the detection rate of autoantibodies in GBS, but also provides a new concept in the antibody-antigen interaction through clustered carbohydrate epitopes. Although ganglioside mimicry is one of the possible etiological causes of GBS, unidentified factors may also contribute to the pathogenesis of GBS. While GBS is not considered a genetic disease, host factors, particularly human lymphocyte antigen type, appear to have a role in the pathogenesis of GBS following C. jejuni infection.

  16. Methane oxidation over A-site ordered and disordered Sr(0.8)Gd(0.2)CoO(3-δ) perovskites.

    PubMed

    Vereshchagin, Sergei N; Solovyov, Leonid A; Rabchevskii, Evgenii V; Dudnikov, Vyacheslav A; Ovchinnikov, Sergey G; Anshits, Alexander G

    2014-06-11

    A tetragonal phase Sr0.8Gd0.2CoO3-δ with ordered Gd(3+)/Sr(2+) ions and oxygen vacancy sites is found to be about five times less active in the reaction of methane combustion than a quenched cubic perovskite phase with randomly distributed (disordered) Gd(3+)/Sr(2+) ions over the A-sites of the crystal lattice. PMID:24777361

  17. Clinical and serological features of acute sensory ataxic neuropathy with antiganglioside antibodies.

    PubMed

    Rojas-García, Ricard; Querol, Luis; Gallardo, Eduard; De Luna Salva, Noemi; Juarez, Cándido; Garces, Mercedes; Fages, Eva; Casasnovas, Carlos; Illa, Isabel

    2012-06-01

    There is as yet no consensus for considering pure acute sensory ataxic neuropathy (ASAN) as a variant of Guillain-Barré syndrome (GBS). Reactivity against gangliosides sharing disialosyl epitopes has been reported in these patients. The aim of this study was to determine the spectrum of reactivity against gangliosides in ASAN and to define the clinical pattern. From our database we identified patients with suspicion of ASAN. We defined ASAN as the presence of ataxia of peripheral origin with loss of proprioception, and areflexia, absence of ophthalmoplegia and no or minimal muscle weakness. Patients who met these criteria were retrospectively reviewed for their spectrum of reactivity against gangliosides and clinical features. We identified 12 patients fulfilling pre-defined criteria for ASAN. Reactivity against gangliosides containing disialosyl epitopes was present in seven patients. Concomitant reactivity against other gangliosides was present in 6/7 patients. All patients presented good prognosis and an antecedent illness was present in nine. Our results support the previously described clinico-immunological association between ASAN and disialosyl specificity, and widen the spectrum of reactivity against gangliosides. The acute presentation with a monophasic course, and good prognosis in all cases, together with transient immunoglobulin G antiganglioside antibodies and infectious antecedent in 7/12 patients support the inclusion of ASAN as a GBS variant. PMID:22734901

  18. Magnetic endohedral metallofullerenes with floppy interiors

    NASA Astrophysics Data System (ADS)

    Qian, Meichun; Ong, Stephen V.; Khanna, Shiv N.; Knickelbein, Mark B.

    2007-03-01

    It is shown that Gd3N@C80 is a highly magnetic and very stable motif that allows enhanced contrast magnetic resonance imaging and electric dipole moment with potential for cancer treatment. Using a synergistic approach combining Stern-Gerlach experiments in beams and first-principles electronic structure studies, it is demonstrated that an isolated Gd3N has a ground state spin moment of 23μB followed by a noncollinear state of 17.2μB only 88meV above the ground state. The large moment is largely due to localized f electrons. As a Gd3N is embedded inside a C80 cage, the localized f electrons maintain the magnetic character while the hybridization between the s , d states of isolated Gd3N and p states of C80 leads to a strongly bound motif with an interaction energy of 13.63eV and a large highest-occupied-molecular-orbital-lowest-unoccupied-molecular-orbital gap of 1.48eV . Gd3N@C80 is further shown to possess two isomers corresponding to the location of the N atom on either side of the Gd3 triangle with an appreciable electric dipole moment and a low barrier of 91meV for transition between them offering potential for a fluctuating dipole.

  19. Bottom-Up Synthesis of Metal-Ion-Doped WS₂ Nanoflakes for Cancer Theranostics.

    PubMed

    Cheng, Liang; Yuan, Chao; Shen, Sida; Yi, Xuan; Gong, Hua; Yang, Kai; Liu, Zhuang

    2015-11-24

    Recently, two-dimensional transition metal dichalcogenides (TMDCs) have received tremendous attention in many fields including biomedicine. Herein, we develop a general method to dope different types of metal ions into WS2 nanoflakes, a typical class of TMDCs, and choose Gd(3+)-doped WS2 (WS2:Gd(3+)) with polyethylene glycol (PEG) modification as a multifunctional agent for imaging-guided combination cancer treatment. While WS2 with strong near-infrared (NIR) absorbance and X-ray attenuation ability enables contrasts in photoacoustic (PA) imaging and computed tomography (CT), Gd(3+) doping offers the nanostructure a paramagnetic property for magnetic resonance (MR) imaging. As revealed by trimodal PA/CT/MR imaging, WS2:Gd(3+)-PEG nanoflakes showed efficient tumor homing after intravenous injection. In vivo cancer treatment study further uncovered that WS2:Gd(3+)-PEG could not only convert NIR light into heat for photothermal therapy (PTT) but also enhance the ionizing irradiation-induced tumor damage to boost radiation therapy (RT). Owing to the improved tumor oxygenation after the mild PTT, the combination of PTT and RT induced by WS2:Gd(3+)-PEG resulted in a remarkable synergistic effect to destroy cancer. Our work highlights the promise of utilizing inherent physical properties of TMDC-based nanostructures, whose functions could be further enriched by elementary doping, for applications in multimodal bioimaging and synergistic cancer therapy.

  20. Bioconjugation of luminescent silicon quantum dots to gadolinium ions for bioimaging applications

    NASA Astrophysics Data System (ADS)

    Erogbogbo, Folarin; Chang, Ching-Wen; May, Jasmine L.; Liu, Liwei; Kumar, Rajiv; Law, Wing-Cheung; Ding, Hong; Yong, Ken Tye; Roy, Indrajit; Sheshadri, Mukund; Swihart, Mark T.; Prasad, Paras N.

    2012-08-01

    Luminescent imaging agents and MRI contrast agents are desirable components in the rational design of multifunctional nanoconstructs for biological imaging applications. Luminescent biocompatible silicon quantum dots (SiQDs) and gadolinium chelates can be applied for fluorescence microscopy and MRI, respectively. Here, we report the first synthesis of a nanocomplex incorporating SiQDs and gadolinium ions (Gd3+) for biological applications. The nanoconstruct is composed of a PEGylated micelle, with hydrophobic SiQDs in its core, covalently bound to DOTA-chelated Gd3+. Dynamic light scattering reveals a radius of 85 nm for these nanoconstructs, which is consistent with the electron microscopy results depicting radii ranging from 25 to 60 nm. Cellular uptake of the probes verified that they maintain their optical properties within the intracellular environment. The magnetic resonance relaxivity of the nanoconstruct was 2.4 mM-1 s-1 (in terms of Gd3+ concentration), calculated to be around 6000 mM-1 s-1 per nanoconstruct. These desirable optical and relaxivity properties of the newly developed probe open the door for use of SiQDs in future multimodal applications such as tumour imaging.Luminescent imaging agents and MRI contrast agents are desirable components in the rational design of multifunctional nanoconstructs for biological imaging applications. Luminescent biocompatible silicon quantum dots (SiQDs) and gadolinium chelates can be applied for fluorescence microscopy and MRI, respectively. Here, we report the first synthesis of a nanocomplex incorporating SiQDs and gadolinium ions (Gd3+) for biological applications. The nanoconstruct is composed of a PEGylated micelle, with hydrophobic SiQDs in its core, covalently bound to DOTA-chelated Gd3+. Dynamic light scattering reveals a radius of 85 nm for these nanoconstructs, which is consistent with the electron microscopy results depicting radii ranging from 25 to 60 nm. Cellular uptake of the probes verified that they

  1. The isothermal section of Gd-Ni-Si system at 1070 K

    NASA Astrophysics Data System (ADS)

    Morozkin, A. V.; Knotko, A. V.; Yapaskurt, V. O.; Manfrinetti, P.; Pani, M.; Provino, A.; Nirmala, R.; Quezado, S.; Malik, S. K.

    2016-03-01

    The Gd-Ni-Si system has been investigated at 1070 K by X-ray and microprobe analyses. The existence of the known compounds, i.e.: GdNi10Si2, GdNi8Si3, GdNi5Si3, GdNi7Si6, GdNi6Si6, GdNi4Si, GdNi2Si2, GdNiSi3, Gd3Ni6Si2, GdNiSi, GdNiSi2, GdNi0.4Si1.6, Gd2Ni2.35Si0.65, Gd3NiSi2, Gd3NiSi3 and Gd6Ni1.67Si3, has been confirmed. Moreover, five new phases have been identified in this system. The crystal structure for four of them has been determined: Gd2Ni16-12.8Si1-4.2 (Th2Zn17-type), GdNi6.6Si6 (GdNi7Si6-type), Gd3Ni8Si (Y3Co8Si-type) and Gd3Ni11.5Si4.2(Gd3Ru4Ga12-type). The compound with composition ~Gd2Ni4Si3 still remains with unknown structure. Quasi-binary phases, solid solutions, were detected at 1070 K to be formed by the binaries GdNi5, GdNi3, GdNi2, GdNi, GdSi2 and GdSi1.67; while no appreciable solubility was observed for the other binary compounds of the Gd-Ni-Si system. Magnetic properties of the GdNi6Si6, GdNi6.6Si6 and Gd3Ni11.5Si4.2 compounds have also been investigated and are here reported.

  2. Neurite outgrowth of neuroblastoma cells: dependence on adhesion surface--cell surface interactions

    PubMed Central

    1984-01-01

    Neurite outgrowth of C 1300 neuroblastoma cells, which were dispersed from adherent cultures or grown in suspension, was studied on different protein-coated surfaces. Of 29 different surface structures studied, including surfaces treated with various fibronectins, lectins, glycosidases, or glycosyltransferases capable of stimulating fibroblast spreading, only the surfaces coated with plasma fibronectin or with a protein mixture secreted by C6 glioma cells displayed an extensive activity in the sprouting assay. Neurite outgrowth was inhibited by brain gangliosides and by colominic acid (a sialic acid polymer). A 50% inhibition of neurite outgrowth of N18 neuroblasts induced by the glioma cell proteins was observed at the following approximate concentration: 100 microM (0.2 mg/ml) GD1A ganglioside, 20 microM (0.04 mg/ml) GT1B ganglioside, and 5 mg/ml colominic acid. Specificity of inhibition was suggested by the finding that a few polyanionic substances tested were not inhibitory in the sprouting assay, and that the type of gangliosides inhibiting sprouting were found to be major sialoglycolipids of the neuroblasts. A hypothesis is discussed, according to which neurite outgrowth of neuroblasts is stimulated by adhesion involving interactions of the adhesion-mediating protein with cell surface carbohydrates characteristic of brain gangliosides. PMID:6699078

  3. Sialylation regulates brain structure and function

    PubMed Central

    Yoo, Seung-Wan; Motari, Mary G.; Susuki, Keiichiro; Prendergast, Jillian; Mountney, Andrea; Hurtado, Andres; Schnaar, Ronald L.

    2015-01-01

    Every cell expresses a molecularly diverse surface glycan coat (glycocalyx) comprising its interface with its cellular environment. In vertebrates, the terminal sugars of the glycocalyx are often sialic acids, 9-carbon backbone anionic sugars implicated in intermolecular and intercellular interactions. The vertebrate brain is particularly enriched in sialic acid-containing glycolipids termed gangliosides. Human congenital disorders of ganglioside biosynthesis result in paraplegia, epilepsy, and intellectual disability. To better understand sialoglycan functions in the nervous system, we studied brain anatomy, histology, biochemistry, and behavior in mice with engineered mutations in St3gal2 and St3gal3, sialyltransferase genes responsible for terminal sialylation of gangliosides and some glycoproteins. St3gal2/3 double-null mice displayed dysmyelination marked by a 40% reduction in major myelin proteins, 30% fewer myelinated axons, a 33% decrease in myelin thickness, and molecular disruptions at nodes of Ranvier. In part, these changes may be due to dysregulation of ganglioside-mediated oligodendroglial precursor cell proliferation. Neuronal markers were also reduced up to 40%, and hippocampal neurons had smaller dendritic arbors. Young adult St3gal2/3 double-null mice displayed impaired motor coordination, disturbed gait, and profound cognitive disability. Comparisons among sialyltransferase mutant mice provide insights into the functional roles of brain gangliosides and sialoglycoproteins consistent with related human congenital disorders.—Yoo, S.-W., Motari, M. G., Susuki, K., Prendergast, J., Mountney, A., Hurtado, A., Schnaar, R. L. Sialylation regulates brain structure and function. PMID:25846372

  4. Ouabain Modulates the Lipid Composition of Hippocampal Plasma Membranes from Rats with LPS-induced Neuroinflammation.

    PubMed

    Garcia, Israel José Pereira; Kinoshita, Paula Fernanda; Scavone, Cristoforo; Mignaco, Julio Alberto; Barbosa, Leandro Augusto de Oliveira; Santos, Hérica de Lima

    2015-12-01

    The effects of ouabain (OUA) and lipopolysaccharide (LPS) in vivo on hippocampal membranes (RHM) of Wistar male rats aged 3 months were analyzed. After intraperitoneal (i.p.) injection of OUA only, LPS only, OUA plus LPS, or saline, the content of proteins, phospholipids, cholesterol and gangliosides from RHM was analyzed. The total protein and cholesterol contents of RHM were not significantly affected by OUA or LPS for the experimentally paired groups. In contrast, total phospholipids and gangliosides were strongly modulated by either OUA or LPS treatments. LPS reduced the total phospholipids (roughly 23 %) and increased the total gangliosides (approximately 40 %). OUA alone increased the total phospholipids (around 23 %) and also the total gangliosides (nearly 34 %). OUA pretreatment compensated the LPS-induced changes, preserving the total phospholipids and gangliosides around the same levels of the control. Thus, an acute treatment with OUA not only modulated the composition of hippocampal membranes from 3-month-old rats, but also was apparently able to counteract membrane alterations resulting from LPS-induced neuroinflammation. This study demonstrates for the first time that the OUA capacity modulates the lipid composition of hippocampal plasma membranes from rats with LPS-induced neuroinflammation.

  5. Evidence for Extracellular ATP as a Stress Signal in a Single-Celled Organism

    PubMed Central

    Sivaramakrishnan, Venketesh

    2015-01-01

    ATP is omnipresent in biology and acts as an extracellular signaling molecule in mammals. Information regarding the signaling function of extracellular ATP in single-celled eukaryotes is lacking. Here, we explore the role of extracellular ATP in cell volume recovery during osmotic swelling in the amoeba Dictyostelium. Release of micromolar ATP could be detected during cell swelling and regulatory cell volume decrease (RVD) phases during hypotonic challenge. Scavenging ATP with apyrase caused profound cell swelling and loss of RVD. Apyrase-induced swelling could be rescued by 100 μM βγ-imidoATP. N-Ethylmalemide (NEM), an inhibitor of vesicular exocytosis, caused heightened cell swelling, loss of RVD, and inhibition of ATP release. Amoebas with impaired contractile vacuole (CV) fusion (drainin knockout [KO] cells) displayed increased swelling but intact ATP release. One hundred micromolar Gd3+ caused cell swelling while blocking any recovery by βγ-imidoATP. ATP release was 4-fold higher in the presence of Gd3+. Cell swelling was associated with an increase in intracellular nitric oxide (NO), with NO-scavenging agents causing cell swelling. Swelling-induced NO production was inhibited by both apyrase and Gd3+, while NO donors rescued apyrase- and Gd3+-induced swelling. These data suggest extracellular ATP released during cell swelling is an important signal that elicits RVD. Though the cell surface receptor for ATP in Dictyostelium remains elusive, we suggest ATP operates through a Gd3+-sensitive receptor that is coupled with intracellular NO production. PMID:26048010

  6. Bacteriophage 933W encodes a functional esterase downstream of the Shiga toxin 2a operon.

    PubMed

    Nübling, Simone; Eisele, Thomas; Stöber, Helen; Funk, Joschua; Polzin, Sabrina; Fischer, Lutz; Schmidt, Herbert

    2014-05-01

    In this study, the 1938bp open reading frame z1466, which is encoded directly downstream the Shiga toxin 2a (Stx2a) operon in E. coli O157:H7 phage 933W was cloned and expressed recombinantly. Purification with Ni-NTA agarose beads with subsequent SDS-PAGE revealed a 68kDa protein, designated 933Wp42-His. Analysis of 933Wp42-His demonstrated an esterase activity by activity staining of native gels using triacetin as a substrate. Purified 933Wp42-His demonstrated a Km value of about 10mM and a Vmax value of 1.667nkat/ml for 4-methylumbelliferyl-acetate (4-MUF-Ac) as a substrate. The enzyme was most active in the pH-range of 7.0-8.0, and at 50°C. Furthermore, 933Wp42-His was able to hydrolyze acetic acid from mucin, and 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac2). This is the first description of an enzymatic activity of the Stx-phage-encoded protein 933Wp42. Its role in substrate utilization during colonization and human infection is discussed.

  7. Sialylation is modulated through maturation in hemocytes from Macrobrachium rosenbergii.

    PubMed

    Sierra, C; Guevara, J; Lascurain, R; Pérez, A; Agundis, C; Zenteno, E; Vázquez, L

    2001-10-01

    In this work we identified in adult and juvenile freshwater prawn, Macrobrachium rosenbergii, three major type of circulating hemocytes: fusiform; rounded; and large ovoid hemocytes. Rounded and large hemocytes represent the first defense line, since this type of cells exerts phagocytic activity as well as lectin synthesis. Considering that glycosylation plays important roles in cell communication and as a target for pathogenic microorganisms, in this report was also described the main glycosidic modifications that occur in the large and rounded hemocytes from the freshwater prawn during maturation as determined with lectins. Neu5Acalpha2,6Gal, was identified homogeneously distributed in the membrane in 90% of hemocytes from juvenile organisms. Maturation of the freshwater prawn induced a decrease or complete loss of Neu5Acalpha2,6Gal residues that were replaced with Neu5Acalpha2,3 molecules in practically all hemocytes from adult organisms. This change was paralleled by a diminution in 9-O-acetyl-neuraminic acid (Neu5,9Ac(2)) expression. T and Tn antigens (Galbetal,3 GalNAcalpha1-0-Ser/Thr or GalNAcalpha1-0-Ser/Thr, respectively), as well as N-glycosidically linked glycans, seem to be highly conserved throughout maturation. Our results show that sialylation of freshwater prawn hemocytes is modulated throughout the maturation process.