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GM1 Ganglioside (gm1 + ganglioside)
Selected AbstractsAccelerated release of exosome-associated GM1 ganglioside (GM1) by endocytic pathway abnormality: another putative pathway for GM1-induced amyloid fibril formationJOURNAL OF NEUROCHEMISTRY, Issue 1 2008Kohei Yuyama Abstract Exosomes are extracellularly released small vesicles that are derived from multivesicular bodies formed via the endocytic pathway. We treated pheochromocytoma PC12 cells with chloroquine, an acidotropic agent, which potently perturbs membrane trafficking from endosomes to lysosomes. Chloroquine treatment increased the level of GM1 ganglioside in cell media only when the cells were exposed to KCl for depolarization, which is known to enhance exosome release from neurons. In the sucrose-density-gradient fractionation of cell media, GM1 ganglioside was exclusively recovered with Alix, a specific marker of exosomes, in the fractions with the density corrresponding to that of exosomes. Notably, amyloid-, assembly was markedly accelerated when incubated with the exosome fraction prepared from the culture media of PC12 cells treated with chloroquine and KCl. Furthermore, amyloid-, assembly was significantly suppressed by the co-incubation with an antibody specific to GM1-bound amyloid-,, an endogenous seed for amyloid formation of Alzheimer's disease. Together with our previous finding that chloroquine treatment induces the accumulation of GM1 ganglioside in early endosomes, results of this study suggest that endocytic pathway abnormality accelerates the release of exosome-associated GM1 ganglioside following its accumulation in early endosomes. Furthermore, this study also suggests that extracellular amyloid fibril formation is induced by not only GM1 gangliosides accumulated on the surface of the cells but also those released in association with exosomes. [source] Identification of a GM1/Sodium,Calcium exchanger complex in the nuclear envelope of non-neuronal cellsJOURNAL OF NEUROCHEMISTRY, Issue 2002X. Xie Our previous studies identified a Na,Ca exchanger (NCX) that is tightly associated with GM1 ganglioside and potentiated by it in the nuclear envelope (NE) of NG108-15 cells and primary neurons. The purpose of the present study was to explore whether this is a general phenomena or limited to neurons. Non-neuronal C6 (glioma), HeLa (Epithelial carcinoma) and NCTC (connective tissue) cell lines were used. Immunocytochemical staining with anti-NCX antibody and cholera toxin B subunit revealed that NCX and GM1 coexist in the nuclei from all 3 cell lines; in relation to plasma membrane, only HeLa cells showed staining for both NCX and GM1. Purified NE and non-nuclear membrane mixture (mainly plasma membrane) from the 3 cell lines were immunoprecipitated with a mouse monoclonal anti-NCX antibody and the precipitated proteins separated on SDS,PAGE. Analysis by immunoblot, showed that NCX is tightly associated with GM1 in the NE of all 3 cell lines. In contrast, NCX and the more loosely associated GM1 from plasma membrane of HeLa cells were separated by SDS,PAGE. Isolated nuclei from C6 cells were used for 45Ca2+ uptake experiments, which provided functional evidence that this exchanger protein is strongly potentiated by GM1. In similar experiments with Jurkat cells (T lymphocyte), no NCX was found. These results suggest a possible new and widely distributed mechanism for regulation of nuclear calcium by NCX in association with GM1. Acknowledgements:, supported by NIH grant NS 33912. [source] Biochemical and immunological characterization of the plant-derived candidate human immunodeficiency virus type 1 mucosal vaccine CTB,MPR649,684PLANT BIOTECHNOLOGY JOURNAL, Issue 2 2009Nobuyuki Matoba Summary Plants are potentially the most economical platforms for the large-scale production of recombinant proteins. Thus, plant-based expression of subunit human immunodeficiency virus type 1 (HIV-1) vaccines provides an opportunity for their global use against the acquired immunodeficiency syndrome pandemic. CTB,MPR649,684[CTB, cholera toxin B subunit; MPR, membrane proximal (ectodomain) region of gp41] is an HIV-1 vaccine candidate that has been shown previously to induce antibodies that block a pathway of HIV-1 mucosal transmission. In this article, the molecular characterization of CTB,MPR649,684 expressed in transgenic Nicotiana benthamiana plants is reported. Virtually all of the CTB,MPR649,684 proteins expressed in the selected line were shown to have assembled into pentameric, GM1 ganglioside-binding complexes. Detailed biochemical analyses on the purified protein revealed that it was N- glycosylated, predominantly with high-mannose-type glycans (more than 75%), as predicted from a consensus asparagine,X,serine/threonine (Asn-X-Ser/Thr) N- glycosylation sequon on the CTB domain and an endoplasmic reticulum retention signal attached at the C-terminus of the fusion protein. Despite this modification, the plant-expressed protein retained the nanomolar affinity to GM1 ganglioside and the critical antigenicity of the MPR649,684 moiety. Furthermore, the protein induced mucosal and serum anti-MPR649,684 antibodies in mice after mucosal prime-systemic boost immunization. Our data indicate that plant-based expression can be a viable alternative for the production of this subunit HIV-1 vaccine candidate. [source] Neurotrophic effects of GM1 ganglioside and electrical stimulation on cochlear spiral ganglion neurons in cats deafened as neonatesTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 6 2007Patricia A. Leake Abstract Previous studies have shown that electrical stimulation of the cochlea by a cochlear implant promotes increased survival of spiral ganglion (SG) neurons in animals deafened early in life (Leake et al. [1999] J Comp Neurol 412:543,562). However, electrical stimulation only partially prevents SG degeneration after deafening and other neurotrophic agents that may be used along with an implant are of great interest. GM1 ganglioside is a glycosphingolipid that has been reported to be beneficial in treating stroke, spinal cord injuries, and Alzheimer's disease. GM1 activates trkB signaling and potentiates neurotrophins, and exogenous administration of GM1 has been shown to reduce SG degeneration after hearing loss. In the present study, animals were deafened as neonates and received daily injections of GM1, beginning either at birth or after animals were deafened and continuing until the time of cochlear implantation. GM1-treated and deafened control groups were examined at 7,8 weeks of age; additional GM1 and no-GM1 deafened control groups received a cochlear implant at 7,8 weeks of age and at least 6 months of unilateral electrical stimulation. Electrical stimulation elicited a significant trophic effect in both the GM1 group and the no-GM1 group as compared to the contralateral, nonstimulated ears. The results also demonstrated a modest initial improvement in SG density with GM1 treatment, which was maintained by and additive with the trophic effect of subsequent electrical stimulation. However, in the deafened ears contralateral to the implant SG soma size was severely reduced several months after withdrawal of GM1 in the absence of electrical activation. J. Comp. Neurol. 501:837,853, 2007. © 2007 Wiley-Liss, Inc. [source] Fetal hydrops in GM1 gangliosidosis: A case reportACTA PAEDIATRICA, Issue 12 2005Maria Teresa Sinelli Abstract GM1 gangliosidosis is a rare disorder characterized by deficiency of the ,-galactosidase enzyme, with the resulting accumulation of glycolipids, oligosaccharides and especially GM1 ganglioside. It can be classified into three clinical types according to the time of onset: infantile, juvenile and adult form. We report a case of GM1 gangliosidosis presenting with fetal hydrops at 24 wk of gestation. The parents were consanguineous; the baby, born at 35 wk of gestation, was dysmorphic and presented severe generalized oedema. The most common cause of fetal hydrops was excluded. A lysosomal storage disease was suspected, and GM1 gangliosidosis was diagnosed. The child developed severe growth and mental retardation and died when she was 21 mo old. Conclusion: We suggest that the possible association between inborn errors of metabolism and antenatal ascites should be considered, in order to offer genetic counselling due to the high recurrence risk and the availability of early antenatal diagnosis. [source] Accelerated release of exosome-associated GM1 ganglioside (GM1) by endocytic pathway abnormality: another putative pathway for GM1-induced amyloid fibril formationJOURNAL OF NEUROCHEMISTRY, Issue 1 2008Kohei Yuyama Abstract Exosomes are extracellularly released small vesicles that are derived from multivesicular bodies formed via the endocytic pathway. We treated pheochromocytoma PC12 cells with chloroquine, an acidotropic agent, which potently perturbs membrane trafficking from endosomes to lysosomes. Chloroquine treatment increased the level of GM1 ganglioside in cell media only when the cells were exposed to KCl for depolarization, which is known to enhance exosome release from neurons. In the sucrose-density-gradient fractionation of cell media, GM1 ganglioside was exclusively recovered with Alix, a specific marker of exosomes, in the fractions with the density corrresponding to that of exosomes. Notably, amyloid-, assembly was markedly accelerated when incubated with the exosome fraction prepared from the culture media of PC12 cells treated with chloroquine and KCl. Furthermore, amyloid-, assembly was significantly suppressed by the co-incubation with an antibody specific to GM1-bound amyloid-,, an endogenous seed for amyloid formation of Alzheimer's disease. Together with our previous finding that chloroquine treatment induces the accumulation of GM1 ganglioside in early endosomes, results of this study suggest that endocytic pathway abnormality accelerates the release of exosome-associated GM1 ganglioside following its accumulation in early endosomes. Furthermore, this study also suggests that extracellular amyloid fibril formation is induced by not only GM1 gangliosides accumulated on the surface of the cells but also those released in association with exosomes. [source] | ||||||||||