Immunocytochemical analysis of gangliosides in rat primary cerebellar cultures using specific monoclonal antibodies

We studied the expression of ganglioside antigens in primary cultures of rat cerebellum using an immunocytochemical technique with mouse monoclonal antibodies (MAbs) specific for various gangliosides. Twelve MAbs that specifically recognize each ganglioside were used. Our study revealed that there is a cell type-specific expression of ganglioside antigens in the primary cultures. A number of b-series gangliosides were detected in the granule cells, whereas a-series gangliosides were not intensely expressed. GD1b was detected in the granule cells. GD2 appeared to be present in a subset of the granule cells or a type of small neurons. GD3 was associated not only with the granule cells, but also with both astrocytes and oligodendrocytes. An O-Ac-disialoganglioside, which was suggested to be O-Ac-LD1, was restrictedly detected in Purkinje cells. The other gangliosides were not detected clearly in these cells. These results suggest that several gangliosides may be useful markers for identifying cells in primary cultures of the rat cerebellum; particularly b-series gangliosides such as GD2 and GD1b for the granule cells and O-Ac-LD1 for Purkinje cells.     

Expression of gangliosides on glial and neuronal cells in normal and pathological adult human brain

Few studies have assessed the glycolipid phenotype of glial cells in the human central nervous system (CNS) in situ. We investigated by immunohistochemistry the expression and cellular distribution of a panel of gangliosides (GM1, GM2, acetyl-GM3, GD1a, GD1b, GD2, GD3, GT1b, GQ1b and the A2B5 antibody) in adult, human normal and pathological brain, namely multiple sclerosis (MS) and other neurological diseases (OND). In normal conditions, we found diffuse expression in the white matter of most gangliosides tested, with the exception of acetyl-GM3, GT1b and GQ1b. By double immunofluorescence with phenotypic markers, GM1 and GD1b were preferentially expressed on GFAP+ astrocytes, GD1a on NG2+ oligodendrocyte precursors, A2B5 immunostained both populations, while GD2 was selectively present on mature oligodendrocytes. In the gray matter, only GM1, GD2 and A2B5 were present on neuronal cells. Interestingly, those gangliosides present on astrocytes in normal conditions were preferentially expressed on NG2+ cells in chronic MS lesions and in OND. Selective expression of GT1b upon astrocytes and NG2+ cells was instead observed in MS lesions, but not in OND. The definition of the glycolipid phenotype of CNS glial cells may be useful to identify distinct biological glial subsets and provide insights on the potential autoantigenic role of gangliosides in CNS autoimmune diseases.     

Ganglioside metabolism in the hippocampus after septal lesion in rats

The changes in ganglioside composition and metabolism of deafferentiated rat hippocampus were estimated after septal lesion. A significant decrease in total ganglioside concentration was found 7 days after the lesion. The reduced level of total gangliosides persisted at 17 and 25 days. Relative increase in the proportion of GD1b and GX (O-acetylated GT1b) and decrease in GM1 were found in hippocampus only at 25 days post-lesion. The incorporation of 3H-N-acetylmannoseamine into gangliosides was examined in rats whose hippocampi were lesioned 25 days prior to radioprecursor injection. Differences in the labeling pattern of total and individual gangliosides were found. Increases in the label in GM1, GD3, and GD1a and decreases in GT1b and GQ1b were found 10 hr after isotope injection. However, decreases in the specific activity of all gangliosides except GT1b and GQ1b were observed 24 hr after 3H-N-acetylomannosamine injection, suggesting the activated turnover of gangliosides in postlesioned hippocampus. The significance of these changes has been discussed in terms of cellular damage and repair in the hippocampal tissue.     

Effect of colchicine on ganglioside composition of rat primary culture neurons.

Developmental changes in gangliosides in the course of neurite outgrowth were examined in dissociated fetal rat cerebral neurons in culture. About a 2-fold increase in ganglioside levels was seen with the progression of neurite formation for up to 24 h in predominantly neuronal cultures. Ganglioside patterns appeared to be unchanged during the first 24 h, subsequently consisted of higher amounts of GD3 and b-series gangliosides (such as GD1b, GT1b, and GQ1b), and lower amounts of a-series gangliosides (GM1 and GD1a). Although the addition of colchicine to the cell growth medium inhibited neurite outgrowth in developing neurons, little if any differences in ganglioside patterns were found between control and colchicine-treated cells. Ganglioside levels decreased slightly in colchicine-treated cells in agreement with the decrease in cell attachment to culture dishes. Although colchicine treatment 8 h after plating caused complete retraction of formed neurites, the ganglioside level of the cells continued to increase during the following 16-hour incubation. Thus, the data suggest that ganglioside synthesis in differentiating neurons does not primarily accompany the expansion in cell surfaces due to neurite formation, and raises the possibility that a large proportion of gangliosides is retained in intracellular compartments.     

Influence of monensin on ganglioside anabolism and neurite stability in cultured chick neurons

We have examined the effects of monensin, a monovalent cationophore that disrupts exo- and endocytosis of membrane vesicles and diminishes Golgi anabolic function, on the incorporation of [3H]-galactose into glycosphingolipids in neurited primary cultures of chick embryo central nervous system neurons. A linear rate of incorporation into all ganglioside species from extracellular-labeled galactose was observed. Specific activity of anabolic labeling was markedly lower in GT1b and GQ1b than in the other major gangliosides of the embryonic neuron (GM3, GD3; GM2, GD2; GM1, GD1a, GD1b). With 100 nM monensin in the extracellular medium, the rate of labeling of GT1b diminished markedly to 20% of control; GD1a, GD1b, and GD2, to 35%; GQ1B to 48%; GD3 to 60%. Vigorous incorporation of label into GM3 was entirely undiminished by monensin. From these findings, it is suggested that ganglioside biosynthesis is compartmentalized in the cytodifferentiating embryonic neuron, with GM3 entirely, and GD3 and GQ1b partially, an extra-Golgi product. Extensive loss of neurites that occurred after several hours of exposure of the neurons to monensin could not be correlated directly with decreased ganglioside anabolism.     

Brief treatment of sensory ganglion neurons with GM1 ganglioside enhances the efficacy of opioid excitatory effects on the action potential

In previous studies, we showed that low (nM) concentrations of opioid prolong the action potential duration (APD) of many mouse dorsal root ganglion (DRG) neurons via Gs-linked excitatory opioid receptors, whereas micromolar opioid levels shorten the APD via Gi/Go-linked inhibitory receptors. In addition, cholera toxin-B subunit (CTX-B) selectively blocks opioid- but not forskolin-induced prolongation of the APD in DRG neurons. Since CTX-B binds with selective high affinity to GM1 ganglioside located on the cell surface, the results suggest that GM1 plays an essential role in regulating excitatory opioid receptor functions. This hypothesis was tested by treating DRG neurons in mouse DRG-cord explants with exogenous gangliosides and determining whether the efficacy of opioid agonists in prolonging the APD is enhanced. The threshold concentration of the opioids, dynorphin(1-13) and morphine required to prolong the APD in many DRG neurons was markedly decreased from nM to fM levels after bath exposure to 10 nM to 1 microM GM1 ganglioside for less than 5 min. In contrast, GM2 and GM3 gangliosides and asialo-GM1 ganglioside were ineffective, even when DRG neurons were exposed to high concentrations (1-10 microM) for periods greater than 1 h. Although GD1a, GD1b and GQ1b gangliosides appeared to be as effective as GM1 when tested at microM concentrations for 15 min, tests at lower concentrations, shorter periods, and/or at lower temperature (24 degrees vs 34 degrees C), showed that they were significantly less effective than GM1.(ABSTRACT TRUNCATED AT 250 WORDS)     

Gangliosides have a bimodal effect on DNA synthesis in U-1242 MG human glioma cells

GM1, GD1a, and GT1b inhibit both PDGF-stimulated and serum-stimulated DNA synthesis in Swiss 3T3 cells and the human glioma cell line U-1242 MG in a dose-dependent manner. The ganglioside inhibitory effect is counteracted in a dose-responsive fashion by serum such that ganglioside-induced inhibition is essentially abolished in 10% serum. Because of the potentially important role that gangliosides play in growth regulation of human gliomas, this phenomenon was studied in detail using U-1242 MG cells. Stimulation of DNA synthesis by low doses of serum in U-1242 MG cells is inhibited in a dose-responsive fashion by ganglioside GM1. However, serum itself counteracts the inhibitory effect of ganglioside in a dose responsive way. Kinetic analyses demonstrate that GM-1 competes with some components of serum for sites on U-1242 MG cells (Kb of GM1 =12.5 μM). On the other hand, GM1, GD1a, and GT1b stimulate DNA synthesis in quiescent U-1242 MG cells in both sparse and confluent conditions, indicating that ganglioside-stimulated DNA synthesis is dependent on the phase of cellular growth rather than cellular density. This growth stimulatory effect of gangliosides is more potent on quiescent, confluent cells than quiescent, sparse cells. These results demonstrate that exogenously added gangliosides can have opposite (bimodal) effects on progression of human glioma cells through the cell cycle depending upon the growth phase of the cells. © 1995 Wiley-Liss, Inc.     

Neurobiology of human oligodendrocytes in culture

Enriched populations of oligodendrocytes were isolated from adult human brains of 3-15 hours postmortem using the trypsinin digestion-Percoll density gradient method and were cultured for an extended period of time up to 6 months. Cell type specific antigens that were expressed by oligodendrocytes were galactocerebroside, myelin basic protein, proteolipid protein, 2'3'-cyclic nucleotide 3'-phosphohydrolase and myelin-associated glycoprotein. In addition, HLA-A,B,C and HLA-DR, respectively, Class I and Class II antigens of the major histocompatibility complex, were demonstrated on oligodendrocytes. Three classes of gangliosides, GM1, GM4, and GD3, were also demonstrated on oligodendrocytes, while GM1 and GM4 gangliosides were detected on the surface of astrocytes. The presence of "transitional" or "bipotential" glial cells that were derived from oligodendrocytes and that expressed both oligodendroglial and astrocytic phenotypes was demonstrated. Treatment of the cells by cyclic AMP and its derivatives reversed this dual phenotypic expression back to the oligodendroglial trait. Electron microscopic examination of oligodendrocytes indicated that they were capable of synthesizing and assembling myelin sheaths in culture in the absence of any neuronal signal input.     

Ganglioside lateralization in the brain of female rats

The ganglioside composition of the cerebral hemispheres of young and adult rats of either sex has been herein assessed for the first time. In females, the total ganglioside content at any age, the content of GM1, GD1a, and GD1b at 8 days, and the content of GM1, GD1b, GT1b, and GQ1b at 60 days were higher in the right than in the left hemisphere. In males, no difference was observed. Concerning the ceramide moiety, a difference was displayed by C18:1 long-chain base in GD1a, whose proportion was higher in the left than in the right hemisphere of females aged 8 days. The comparison between homolateral hemispheres of rats of different sex revealed several differences. On average, in 8-day-old animals, the content of gangliosides was higher in females than in males. At 60 days the amount of gangliosides was on average lower in females than in males, even if with some exception. The data obtained with the current investigation show the existence of a ganglioside lateralization in rat brain, exclusively in females, and almost entirely at charge of the oligosaccharide portion. Moreover, age-dependent changes of ganglioside pattern and content show a dependence on brain lateralization. J. Neurosci. Res. 50:643–648, 1997. © 1997 Wiley-Liss, Inc.     

Differentiation of oligodendrocytes cultured from developing rat brain is enhanced by exogenous GM3 ganglioside

Cultures consisting primarily of O-2A progenitor cells and immature oligodendrocytes with a few microglia and astrocytes were obtained by shaking primary cultures from neonatal rat brain after 12--14 days in vitro. Addition of 50 μg/ml exogenous Neu-NAcα2-3Galβ1-1′ ceramide (GM3 ganglioside) to the cultures resulted in an increase in the number and thickness of cell processes that stained intensely for sulfatide and galactocerebroside (galC) in comparison to control cultures without added GM3. The treated cultures also contained fewer astrocytes than control cultures as revealed by immunostaining for glial fibrillary acidic protein (GFAP). Cells that immunostained for both GFAP and sulfatide/galC were very rare in control cultures but were frequently seen in the GM3-treated cultures, suggesting that these may represent cells changing their direction of differentiation away from type II astrocytes toward oligodendrocytes under the influence of GM3. These effects on the developing rat oligodendrocytes were specific for GM3 ganglioside and were not produced by adding GM1, GM2, GD3, or GD1a to the cultures. Lactosyl ceramide and neuraminyl lactose were also ineffective. When control cultures were initially plated on polylysine and incubated with [¹⁴C]galactose, GD3 was the principal labeled ganglioside. However, as the control cells differentiated over time in culture without the addition of exogenous GM3 and produced increasing amounts of myelin-related components, the incorporation of [¹⁴C]galactose into endogenous GM3 increased to become the predominant labeled ganglioside by 6 days after plating. Metabolic labeling of the GM3-treated oligodendrocytes with [¹⁴C]galactose revealed increased incorporation into galC and sulfatide in comparison to control cultures, but a decreased labeling of endogenous GM3. Similarly, incorporation of an amino acid precursor into the myelin-associated glycoprotein (MAG) was increased by GM3 treatment, but incorporation into myelin basic protein (MBP) was not affected. Although the overall effect of added GM3 was to decrease the phosphorylation of most proteins in the oligodendrocytes, including MBP, GM3 enhanced the phosphorylation of MAG. These findings indicate that GM3 ganglioside has an important role in the differentiation of cells of the O-2A lineage toward myelin production, since differentiation is associated with increased metabolic labeling of endogenous GM3 in control cultures and is enhanced by the addition of exogenous GM3. © 1994 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

GD3 ganglioside is prevalent in fully differentiated neurons from rat retina

Adult mammalian retinas contain unusually high amounts of GD3, a ganglioside of the lactosylceramide series. In this respect, they differ from adult avian retina and other regions of the adult avian and mammalian brain, where GD3 is a minor ganglioside and gangliosides of the gangliotetraosylceramide series (GM1, GD1a, GD1b, GT1b) are the predominant ones. We compare here the ganglioside patterns of rat, human, horse, and guinea pig retinas, which are known to differ in the degree of vascularization and astrocytic cell content. All these retinas showed a prevalence of pathway "b" gangliosides over pathway "a" gangliosides but showed no correlation between GD3 content and the degree of vascularization and astrocytic cell content. Immunostaining of rat retina sections showed the presence of GD3 in the inner and outer plexiform layers and also in the ganglion cell and inner nuclear layers. About 60% of the cells dissociated from rat retina showed immuno-colocalization of GD3 and the neuronal marker class III beta tubulin isotype or cholera toxin binding. All morphologically identifiable glial Muller cells coexpress GD3 and gangliotetraosylgangliosides. GD3 was a minor ganglioside among these axonally transported by ganglion cells in rats and guinea pigs, suggesting that it is either not synthesized by ganglion cells or, if so, it is restricted to the cell soma and/or dendritic tree. Our results demonstrate that, unlike neurons from avian retina and other regions of avian and mammalian brain, neurons from mammalian retina not only contain gangliosides of the gangliotetraosylceramide series but also keep a prevalence of gangliosides of the lactosylceramide series (GD3) when they are fully differentiated.     

Cell-type-specific markers for distinguishing and studying neurons and the major classes of glial cells in culture

We have used 4 cell-type-specific markers to identify individual glial and neuronal cells in dissociated cell cultures of neonatal rat sciatic nerve, dorsal root ganglia (DRG), optic nerve, cerebellum, corpus callosum, cerebral cortex and leptomeninges. Schwann cells were identified with antibodies against rat neural antigen-1 (Ran-1), neurons with tetanus toxin, astrocytes with antibody against the glial fibrillary acidic protein (GFAP) and oligodendrocytes with antibody against galactocerebroside. All of these ligands react with cell surface molecules except for anti-GFAP antibody which binds to intracellular glial filaments. Using two-fluorochrome immunofluorescence we have studied the distribution of various glycoproteins and glycolipids on these 4 major neural cell types in short-term cultures. We have found that (1) although Ran-1 is expressed on glial and neuronal tumours, it was not found on normal astrocytes, oligodendrocytes or neurons; (2) Thy-1 was present on fibroblasts and some neurons but not on the majority of leptomeningeal cells or on oligodendrocytes or astrocytes in short-term cultures (however, it was expressed on some astrocytes in longer term cultures); (3) the 'large external transformation sensitive' (LETS) protein could be detected on fibroblasts and leptomeningeal cells but not on neurons or glial cells; (4) GM1 was present on all neurons, most oligodendrocytes and approx. 50% of other cell types; sulfatide and GM3 were only detectable on oligodendrocytes, while globoside was only found on some neurons. In addition, we were able to identify putative microglial cells by the presence of cell surface receptors for IgG and by their phagocytic activity; they did not express and of the cell-type-specific defining markers.     

GQ1b-seronegative Fisher syndrome: clinical features and new serological markers

IgG anti-GQ1b antibodies are a powerful serological marker for the diagnosis of Fisher syndrome (FS), but little is known regarding serological markers in FS patients that do not have the autoantibodies. The authors analyzed IgG antibodies against gangliosides other than GQ1b, ganglioside complexes, and ganglioside-like lipo-oligosaccharide (LOS) of Campylobacter jejuni isolates from FS patients. We identified 24 (12%) patients with GQ1b-seronegative FS among 207 FS patients who had been referred to our laboratory for anti-ganglioside antibody testing. Patients with GQ1b-seronegative FS were male and had a history of antecedent gastrointestinal illness more frequently than FS patients with IgG anti-GQ1b antibodies. Other clinical features during the illness were not distinguishing for GQ1b-seronegative FS. Four (17%) of 24 patients with GQ1b-seronegative FS had IgG antibodies against single gangliosides such as GM1b, GD1a, or GT1a. Antibodies against GM1 and GT1a complex were detected in four GQ1b-seronegative FS patients, three of whom did not have antibodies against single gangliosides. Mass spectrometry analysis showed that C. jejuni isolates from FS patients had GD1c-, GalNAc-GM1b-, or GalNAc-GD1c-like LOS, and not GQ1b-like LOS, highlighting the utility of examining serum antibodies against these ganglioside mimics in GQ1b-seronegative FS patients. Seven (29%) had IgG antibodies against the LOS from C. jejuni strains expressing GD1c-, GalNAc-GM1b-, or GalNAc-GD1c-like LOS. These findings suggest that IgG antibodies against GM1b, GD1c, GalNAc-GM1b, and ganglioside complexes are serological markers for GQ1b-seronegative Fisher syndrome.     

Sensory neuropathy associated with monoclonal immunoglobulin M to GD1b ganglioside

A 67-year-old woman with a sensory polyneuropathy was shown to have a serum monoclonal immunoglobulin M λ antibody with a titer of 1:10,000 toward GD1b ganglioside. The immunoglobulin M also reacted with some other gangliosides containing disialosyl groups such as GD2, GD3, and GQ1b, but it did not react with GM1, LM1, or GD1a. The principal reactive ganglioside in human cauda equina was GD1b.     

Reversibility of ganglioside effects on astrocyte morphology

The B-subunit of cholera toxin (BCT) induces a morphological change in cultured rat cerebral astrocytes from flat (epithelioid) to stellate (process-bearing). This stellation is reversed by the gangliosides GM1 and GD1a at concentrations of 10 microM or higher. Upon changing to a ganglioside-free medium, the flat astrocytes reacquire the stellate morphology within 3 hr, indicating that the antistellation effect of gangliosides is reversible. The possibility that this reversibility was due to a loss of exogenously acquired gangliosides from the cell membrane can be ruled out since pretreatment with GM1, but not GD1a, which does not bind BCT, results in an increased responsiveness to BCT, which was identical whether measured immediately after withdrawal of the ganglioside or 3 hr later. Asialo-GM1, which neither binds BCT nor reverses BCT-induced stellation by itself, prevents the return to stellation after withdrawal of the gangliosides. These data suggest that while gangliosides remain associated with the cell, their effect on astrocytes can change from opposing to permitting the stellate morphology.     

GT3 and its O-acetylated derivative are the principal A2B5-reactive gangliosides in cultured O2A lineage cells and are down-regulated along with O-acetyl GD3 during differentiation to oligodendrocytes.

Among the developmentally regulated antigens expressed on the surface of bipotential glial precursors isolated from neonatal rat brain are the gangliosides recognized by the monoclonal antibody A2B5. Immunostaining of thin layer chromatograms showed that oligodendrocyte-type 2 astrocyte (O2A) progenitors in culture express two ganglioside antigens that react strongly with the A2B5 antibody. Both ganglioside antigens are down-regulated as the cells differentiate to oligodendrocytes, corresponding to the disappearance of cell surface immunostaining by A2B5 in mature oligodendrocytes. By contrast, both gangliosides continue to be expressed when the cells differentiate to type-2 astrocytes. These two A2B5-reactive gangliosides in O2A lineage cells were identified as GT3 and O-acetyl GT3 by using the monoclonal antibody 18B8 that recognizes GT3 and an influenza C virus esterase that specifically removes O-acetyl moieties from sialic acids. Thin-layer chromatographic immunostaining with the JONES monoclonal antibody demonstrated that the progenitor cells in culture also express O-acetyl GD3, which is similarly down-regulated in oligodendrocytes, but retained in type-2 astrocytes. The 18B8 and JONES antibodies also immunostained the surface of O2A progenitors. Therefore, expression of GT3 and O-acetylation of GT3 and GD3 occur during the proliferative and migratory stages of glial cell development. Published 1999 Wiley-Liss, Inc.     

Developmental changes of ganglioside expressions in postnatal rat cerebellar cortex

We previously described the differential distribution of gangliosides in adult rat brain as detected by specific antibodies. We report here the distribution of gangliosides during the development of postnatal rat cerebellum by an immunofluorescence technique with mouse monoclonal antibodies (mAbs). Eleven mAbs that specifically recognize each ganglioside were used. Our study revealed that the expression of each ganglioside changed dramatically during the development. GD3 and O-Ac-GD3 were expressed intensely in the external granular layer at 1, 5, and 10 days, whereas GD2 was firstly detected in the internal granular layer at 5 days and GD1b was diffusely detected throughout all layers of the cerebellar cortex at early postnatal days. GD2 and GD1b were more intensely expressed in the granular layer at 20, 30, and 80 days, suggesting that premature granule cells express GD3 and its derivative, O-Ac-GD3, whereas mature granule cells express GD2 and GD1b intensely. On the other hand, GM1 was exclusively detected in the external granular layer and the molecular layer at 1 and 5 days. The staining sites spread gradually from these outer layers into the internal granular layer and the white matter after 10 days. The positive cells in the external granular layer and the molecular layer appeared to be Bergmann glial cells and their radially ascending cytoplasmic processes. The intensity of the staining in these specialized astroglial cells decreased gradually during postnatal days. In contrast, the expression of GQ1b was very faint at birth, but gradually increased during the development and was detected intensely in the internal granular layer, particularly in the cerebellar glomeruli in adulthood, suggesting that GQ1b expression may be associated with synapse-related structures. The developmental changes of the expression of other gangliosides were also recognized in the postnatal rat cerebellum. These results suggest that specific gangliosides may play an important role in regulating the early events responsible for the orderly formation of the cerebellar cortex.     

In vitro modulation of changes in ganglioside patterns of differentiating neurons in the presence of an anti-GM1 antibody

Retinal cells from 7-day-old chicken embryos were cultured in the presence of a polyclonal anti-GMI antibody, at low and high density in a “sandwich cell culture”. Cells that were about 80% neurofilament positive at all times, changed their morphology and emitted processes as controls. By examining immunocytochemical expression of gangliosides, cells cultured in the presence of the antibody maintained GD3 expression longer than controls, albeit the expression of the gangliotetraosylgangliosides (GTOG) was not considerably affected. This leads to an extension of the transient period in which differentiating cells coexpressed both types of gangliosides (GD3 and GTOG). At 3–4 days in vitro the relative synthesis of GD3 was about 30% higher and that of GD1a about 40% lower than in controls, indicating a delay in the shift of the synthesis pattern. Nevertheless, the pattern of ganglioside composition resembled at 4 days in vitro. Results indicate that the anti-GMI antibody may modulate the expression and synthesis of gangliosides without a detectable decrease in neuritogenesis. Considering that the emission of neurites occurs in coexpressing GD3 and GTOG neurons, it is suggested that neuritogenesis could be irrespective of losing the GD3 expression.     

Gangliosides of human cerebrospinal fluid in various neurologic diseases.

Simultaneous profile determination and quantification of human cerebrospinal fluid (CSF) gangliosides in various neurologic diseases (n = 71) was examined. Gangliosides were extracted with methanol/chloroform from clinically available amounts of CSF (4-5 ml), then separated and quantified by high-performance thin-layer chromatography (HPTLC) and direct densitometry. Based on chromatographic comparison with standards, the percentage of lipid-bound NeuAc positive fractions in 'normal' CSF samples were: GM1 (II3 NeuAc-GgOse4Cer) (3%); GD3 (II3 NeuAc2-Lac-Cer) (4%); GD1a (IV3 NeuAc, II3 NeuAc-GgOse4 Cer) (15%); X1 (3%); GD1b (II3(NeuAc)2-GgOse4 Cer) (16%); X2 (4%); GT1b (IV3 NeuAc, II3(NeuAc)2-GgOse4-Cer) (40%); and GQ1b (IV3(NeuAc)2, II3(NeuAc)2-GgOse4-Cer (15%). Similarity between CSF and CSF and human cerebellar cortex, particularly in proportion of "b" series gangliosides (GQ1b, GT1b, GD1b), could be observed. A higher proportion of GD1a ganglioside, with decreased GQ1b was found in infancy. The total ganglioside content (mean +/- 2 SD) varied between 645-894 micrograms/l. Significant alterations of the CSF ganglioside profile, with an increase in less polar gangliosides, GM3 and GD3, correlated with the blood-brain barrier dysfunction (CSF hemorrhages, compressive syndrome), or some malignant processes (metastatic brain melanoma). A statistically significant increase in the content of total CSF gangliosides was found in the following groups of patients as compared to controls: (1) ischemic cerebrovascular accident (CVI) with good outcome (P less than 0.02); (2) peripheral neuropathy and polyneuropathy (P less than 0.001) and (3) intravertebral discopathy (P less than 0.05). A significant decrease in the content of total CSF gangliosides was found in CVI group with lethal outcome (P less than 0.05).     

Gangliosides in lesion-induced synaptogenesis: studies in the hippocampus of the rat brain

Changes in ganglioside composition, biosynthesis and individual distribution were studied in hippocampal regions after unilateral destruction of the entorhinal cortex. After 1 and 3 days postlesion (dpl), a decrease in ganglioside content was detected in area dentata (AD) and pyramidal cell regions CA1-CA3 (CA), both ipsilateral and contralateral to the lesion. By 5 dpl all the values had returned to control values, except in AD which showed a dramatic increase in total ganglioside content reaching a maximum at 12 dpl. By 30 dpl this area also showed control content. A significant increase in biosynthesis of gangliosides was observed at 5 and 8 dpl in the hippocampus ipsilateral to the lesion without changes in the contralateral counterpart. Individual ganglioside distribution showed a pronounced change in GM1 and GQ1b with small changes in the other major gangliosides. Significant differences were observed in the distribution of gangliosides between the two hippocampal regions studied in unoperated control animals. GD1a was more concentrated in AD, whereas GQ1b, GT1b and GD1b predominated in CA. The data presented here indicate that important modifications in ganglioside content as well as pattern occur in the deafferented hippocampus a phenomenon that could be related with the known effect of gangliosides on neuritogenesis observed in cell culture studies.