g(m1)-ganglioside and gangliotetraose

Knock-out (KO) mice lacking gangliotetraose gangliosides attributable to disruption of the gene for GM2/GD2 synthase [GalNAcT (UDP-N-acetylgalactosamine:GM3/GD3 beta-1,4-N-acetylgalactosaminyltransferase; EC 2.4.1.92 [EC])] are revealing key neural functions for the complex gangliosides of brain. This study has found such animals to be highly susceptible to kainic acid (KA)-induced seizures in terms of both seizure severity and duration. Intraperitoneal injection of 25 mg/kg KA produced status epilepticus for approximately 200 min in normal mice or heterozygotes and more than four times longer in the KO mice. The latter group suffered approximately 30% mortality, which increased to approximately 75% at dosage of 30 mg/kg KA, compared with 10-14% for the other two genotypes at the latter dosage. Nissl staining and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling assay revealed substantial deterioration of pyramidal neurons attributable to apoptosis in the KO hippocampus, especially the CA3 region. Seizure activity in the KO mouse was only moderately diminished by intraperitoneal injection of GM1 ganglioside, whereas LIGA 20, a semisynthetic analog of GM1, substantially reduced both seizure severity and cell damage. The potency of LIGA 20 was correlated with its enhanced membrane permeability (compared with GM1), as seen in the increased uptake of [3H]LIGA 20 into the subcellular fractions of brain including cell nuclei. The latter finding is consonant with LIGA 20-induced restoration of the Na+/Ca2+ exchanger located at the inner membrane of the nuclear envelope in KO mice, an exchanger dependent on tight association with GM1 or its analog for optimal activity. These results point to a neuroprotective role for GM1 and its associated exchanger in the nucleus, based on regulation of Ca2+ flux between nucleoplasm and nuclear envelope.

Topics: Animals; Apoptosis; Brain; Disease Susceptibility; G(M1) Ganglioside; Gangliosides; Hippocampus; Kainic Acid; Mice; Mice, Inbred C57BL; Mice, Knockout; N-Acetylgalactosaminyltransferases; Neurons; Neuroprotective Agents; Oligosaccharides; Seizures; Sodium-Calcium Exchanger; Sphingosine; Status Epilepticus; Time Factors

Gangliosides from histopathologically-defined human cerebrum-resembling remnant and cerebellum from 37 and 30 gestational week-old anencephaluses were identified using mass spectrometry and high performance thin layer chromatography combined with immunochemical analysis in comparison to respective normal newborn/fetal and adult brain regions. A novel strategy of nano-electrospray ionization quadrupole time-of-flight tandem MS has been developed for identification of ganglioside components in complex mixtures. By morphoanatomical and histological investigation the anencephalic cerebral remnant was found to be aberrant, while the anencephalic cerebellum was defined as normal. Total ganglioside concentrations in the anencephalic cerebral remnant and the cerebellum were 34% and 13% lower in relation to the age-matched controls. In the cerebral remnant, GD3, GM2 and GT1b were elevated, while GD1a was decreased in the anencephalic cerebral remnant, but enriched in anencephalic cerebellum. GQ1b was reduced in both anencephalic regions. Gg4Cer, GM1b and GD1alpha, members of the alpha-series biosynthetic pathway, and neolacto-series gangliosides were found to be present in anencephalic, as well as in normal, fetal and adult brain tissues, indicating the occurrence of these biosynthetic pathways in human brain. In both cerebral and cerebellar anencephalic tissues, GM1b, GD1alpha, nLM1 and nLD1 were expressed at a higher rate in relation to normal tissue. It can be demonstrated that the anencephalic cerebral remnant, as a primitive brain structure, represents a naturally-occurring model to study the ganglioside involvement in induction of aberrant brain development.

Topics: Anencephaly; Brain; Carbohydrate Sequence; G(M1) Ganglioside; Gangliosides; Globosides; Glycosphingolipids; Humans; Molecular Sequence Data; Oligosaccharides; Reference Values; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Fast Atom Bombardment

Dowex-50W-H+ was used to catalyze the highly selective desialylation of polysialylated ganglio-N-tetraose series gangliosides to yield primarily GM1. High performance thin-layer chromatographic analysis of recovered lipid indicated that 60-70% of the recovered ganglioside was GM1. Identification of the major product as GM1 was confirmed by proton NMR spectra and lack of sialic acid release by Vibrio cholerae sialidase.

Topics: Animals; Anion Exchange Resins; Brain Chemistry; Cattle; Chromatography, High Pressure Liquid; G(M1) Ganglioside; Gangliosides; Magnetic Resonance Spectroscopy; Neuraminidase; Oligosaccharides; Resins, Synthetic; Sialic Acids; Vibrio cholerae