Gangliosides of human, bovine and rabbit retina

Sialidase neu4 deficiency is associated with neuroinflammation in mice

Sialidases catalyze the removal of sialic acid residues from glycoproteins, oligosaccharides, and sialylated glycolipids. Sialidase Neu4 is in the lysosome and has broad substrate specificity. Previously generated Neu4-/- mice were viable, fertile and lacked gross morphological abnormalities, but displayed a marked vacuolization and lysosomal storage in lung and spleen cells. In addition, we showed that there is an increased level of GD1a ganglioside and a markedly decreased level of GM1 ganglioside in the brain of Neu4-/- mice. In this study, we further explored whether sialidase Neu4 deficiency causes neuroinflammation. We demostrated that elevated level of GD1a and GT1b is associated with an increased level of LAMP1-positive lysosomal vesicles and Tunel-positive neurons correlated with alterations in the expression of cytokines and chemokines in adult Neu4-/- mice. Astrogliosis and microgliosis were also significantly enhanced in the hippocampus, and cerebellum. These changes in brain immunity were accompanied by motor impairment in these mice. Our results indicate that sialidase Neu4 is a novel mediator of an inflammatory response in the mouse brain due to the altered catabolism of gangliosides.

Influenza A virus survival in water is influenced by the origin species of the host cell

Background

Influenza A viruses have an envelope made of a lipid bilayer and two surface glycoproteins, the hemagglutinin and the neuraminidase. The structure of the virus is directly dependent on the genetic makeup of the viral genome except the glycosylation moieties and the composition of the lipid bilayer. They both depend on the host cell and are in direct contact with the environment, such as air or water. Virus survival is important for virus transmission from contaminated waters in the case of wild aquatic birds or from contaminated surface or air for humans.

Objective

The objective of this study was to check whether the origin species of the host cell has an influence on influenza A virus survival.

Method

The persistence in water at 35°C of viruses grown on either mammalian cells or avian cells and belonging to two different subtypes H1N1 and H5N1 was compared.

Results

Both H5N1 and H1N1 viruses remained infectious for periods of time as long as 19–25 days, respectively. However, within the same subtype, viruses grown on mammalian cells were more stable in water at 35°C than their counterparts grown on avian cells, even for viruses sharing the same genetic background.

Conclusions

This difference in virus stability outside the host is probably connected to the nature of the lipid bilayer taken from the cell or to the carbohydrate side chains of the virus surface glycoproteins. Moreover, the long-lasting survival time might have a critical role in the ecology of influenza viruses, especially for avian viruses.

Molecular cloning and characterization of the expression pattern of the zebrafish alpha2, 8-sialyltransferases (ST8Sia) in the developing nervous system

Sialyltransferases are Golgi type II transmembrane glycoproteins involved in the biosynthesis of sialylated glycolipids and glycoproteins. These sialylated compounds play fundamental roles in the development of a variety of tissues including the nervous system. In this study, we have molecularly cloned from zebrafish sources, the orthologues of the six human alpha2,8-sialyltransferases (ST8Sia), a family of sialyltransferases implicated in the alpha2-8-mono-, oligo-, and poly-sialylation of glycoproteins and gangliosides and we have analysed their expression pattern in the embryonic zebrafish nervous system, using in situ hybridization. Our results show that all six ST8Sia exhibit distinct and overlapping patterns of expression in the developing zebrafish central nervous system with spatial and temporal regulation of the expression of these genes, which suggests a role for the alpha2-8-sialylated compounds in the developing nervous system.

Neurochemical, morphological, and neurophysiological abnormalities in retinas of Sandhoff and GM1 gangliosidosis mice

Retinal abnormalities are well documented in patients with ganglioside storage diseases. The total content and distribution of retinal glycosphingolipids was studied for the first time in control mice and in Sandhoff disease (SD) and GM1 gangliosidosis mice. Light and electron microscopy of the SD and the GM1 retinas revealed storage in ganglion cells. Similar to previous findings in rat retina, GD3 was the major ganglioside in mouse retina, while GM2 and GM1 were minor species. Total ganglioside content was 44% and 40% higher in the SD and the GM1 retinas, respectively, than in the control retinas. Furthermore, GM2 and GM1 content were 11-fold and 51-fold higher in the SD and the GM1 retinas than in the control retinas, respectively. High concentrations of asialo-GM2 and asialo-GM1 were found in the SD and the GM1 retinas, respectively, but were undetectable in the control retinas. The GSL abnormalities in the SD and the GM1 retinas reflect significant reductions in beta-hexosaminidase and beta-galactosidase enzyme activities, respectively. Although electroretinograms appeared normal in the SD and the GM1 mice, visual evoked potentials were subnormal in both mutants, indicating visual impairments. Our findings present a model system for assessing retinal pathobiology and therapies for the gangliosidoses.

Phosphate-limited oat. The plasma membrane and the tonoplast as major targets for phospholipid-to-glycolipid replacement and stimulation of phospholipases in the plasma membrane

We recently reported that cultivation of oat (Avena sativa L.) without phosphate resulted in plasma membrane phosphoglycerolipids being replaced to a large extent by digalactosyldiacylglycerol (DGDG) (Andersson, M. X., Stridh, M. H., Larsson, K. E., Liljenberg, C., and Sandelius, A. S. (2003) FEBS Lett. 537, 128-132). We report here that DGDG is not the only non-phosphorous-containing lipid that replaces phospholipids but that also the content of glucosylceramides and sterolglycosides increased in plasma membranes as a response to phosphate starvation. In addition, phosphate deficiency induced similar changes in lipid composition in the tonoplast. The phospholipid-to-glycolipid replacement apparently did not occur to any greater extent in endoplasmic reticulum, Golgi apparatus, or mitochondrial inner membranes. In contrast to the marked effects on lipid composition, the polypeptide patterns were largely similar between root plasma membranes from well-fertilized and phosphate-limited oat, although the latter condition induced at least four polypeptides, including a chaperone of the HSP80 or HSP90 family, a phosphate transporter, and a bacterial-type phosphoesterase. The latter polypeptide reacted with an antibody raised against a phosphate deficiency-induced phospholipase C from Arabidopsis thaliana (Nakamura, Y., Awai, K., Masuda, T., Yoshioka, Y., Takamiya, K., and Ohta, H. (2005) J. Biol. Chem. 280, 7469-7476). In plasma membranes from oat, however, a phospholipase D-type activity and a phosphatidic acid phosphatase were the dominant lipase activities induced by phosphate deficiency. Our results reflect a highly developed plasticity in the lipid composition of the plasma membrane and the tonoplast. In addition, phosphate deficiency-induced alterations in plasma membrane lipid composition may involve different sets of lipid-metabolizing enzymes in different plant tissues or species, at different stages of plant development and/or at different stages of stress adjustments.

Lipid changes in Niemann-Pick disease type C brain: personal experience and review of the literature

Niemann-Pick disease type C (NPC) is a neurovisceral disorder characterized by lysosomal sequestration of endocytosed LDL-cholesterol, premature and abnormal enrichment of cholesterol in trans Golgi cisternae and accompanying anomalies in intracellular sterol trafficking. In addition to cholesterol, the NPC lesion has also been shown to impact the metabolism of sphingolipids. Lipids, more particularly glycolipids, were studied in brain tissue from eight cases with proven NPC, ranging from 21 fetal weeks to 19 years of age (one case with rapidly fatal neonatal cholestatic icterus, three cases with infantile neurological onset, one late infantile and two juvenile neurological cases). In gray matter, the concentrations of total cholesterol, sphingomyelin and total gangliosides were within the normal range in all cases. In white matter, a severe loss of galactosylceramide and other myelin lipids (including cholesterol) was prominent in patients with the neurological severe infantile form (levels similar to those in 6-8 month-old infants) or the late infantile form of the disease, but only a slight decrease was observed in patients with a juvenile neurological onset. Analysis of the ganglioside profiles and study of minor neutral glycolipids revealed striking abnormalities, although not present at the fetal stage. In cerebral cortex, gangliosides GM3 and GM2 showed a significant increase, 10-15 fold and 3-5-fold the normal level, respectively, with already some abnormalities in a 3-month-old patient. Except in the latter patient, a prominent storage of glucosylceramide, lactosylceramide and gangliotriaosylceramide (asialo-GM2) was observed, with 10-50-fold increases from the normal concentration. The fatty acid composition of these glycolipids suggests that they have a neuronal origin. A slight increase of globotriaosyl- and globotetraosylceramide and of more complex neutral glycolipids also occurred. While ganglioside changes were essentially similar in gray and white matter, changes of the neutral glycolipids were only minimal in the latter. Our data are in good accordance with previous studies and provide additional information. They emphasize that, apart a varying demyelinating process (most pronounced in children with a severe infantile neurological form) brain lipids abnormalities are essentially located to the gray matter. They confirm and give more precise information on the glycolipid nature of the neuronal storage, and establish that a similar type of changes occurs in the different neurological forms of the disease. Yet, our study indicates that glycolipid changes in brain do not occur before a few months after birth, possibly at a period concomitant with the onset of neurological symptoms, in contrast to the very early glycolipid abnormalities observed in non-neural organs. Glycolipid changes rather similar to those seen in NPC brain, in particular for gangliosides, have been described for other lysosomal disorders such as Niemann-Pick type A and mucopolysaccharidoses. The glucosyl-and lactosylceramide accumulation, however, is more striking in NPC, especially taking into account that there is no other known storage in NPC brain. Some neuropathological changes, such as ectopic neurites, could be related to the glycolipid changes. Metabolic studies in cultured fibroblasts combined to the observation that no lipids other than glycolipids accumulate in brain suggest that the NPC gene products possibly participate in intracellular transport or regulate metabolism of glycolipids.

Successive isolation and separation of the major lipid fractions including gangliosides from single biological samples

Currently available techniques concerning extraction and characterization of the different lipids from biological specimens are designed for particular families and do not address consecutive isolation of lipid constituents in their globality. We describe here a simple, nondestructive chromatographic procedure that allows efficient elution and further analysis of the major lipid classes (neutral lipids, phospholipids, nonsialylated sphingolipids, and gangliosides) in their natural states from the same starting material. The procedure describes the use of solvent mixtures adapted to silicic acid column chromatography and permits 90-97% recovery of each of the above lipid groups. We have particularly concentrated on optimizing the efficient recovery of the diverse minor forms of gangliosides, free of other contaminants, from relatively small amounts of neural tissue. As model systems we have used in vivo and in vitro preparations of mammalian retina for which only fragmentary data are available on lipid composition. We show that relative to brain, retina contains, for example, twofold more sphingomyelin and sixfold more GD3 ganglioside. In turn, cultured retinal glial cells contain twofold higher levels of globoside and eightfold higher amounts of GM3 ganglioside with respect to intact retina. Compared to previously published techniques, we obtain improved total ganglioside recovery, with enrichment of poly-sialogangliosides. The technique presented here should be widely applicable to analyze global lipid composition of diverse biological samples.

Site restricted and neuron dominant expression of alpha 2,8sialyltransferase gene in the adult mouse brain and retina

Gene expression of the alpha 2,8sialyltransferase (alpha 2,8S-T) responsible for GD3 synthesis in the adult mouse brain and retina was analysed by reverse transcription-polymerase chain reaction/Southern blotting (RT-PCR/Southern) and in situ hybridization. Among various portions of the brain, high levels of 9.5 kb mRNA were observed in the retina and midbrain. Results of RT-PCR/Southern did not necessarily correlate with the enzyme activities in the individual sites. In situ hybridization analysis revealed that this gene was characteristically expressed in the inner segment of photoreceptor cells, some nuclei in the midbrain, cranial nerve nuclei in the pons-medulla, Purkinje cells in the cerebellum, pyramidal cells of the hippocampus and granular cells of the dentate gyrus. In the retina, the alpha 2,8S-T gene was broadly expressed over the layers during development, and retained high expression levels in the photoreceptor cells of adult mice consistent with high expression of GD3. Destruction of neurons in the hippocampus and dentate gyrus by injection of kainic acid and colchicine respectively resulted in the disappearance of the hybridization signal, suggesting that the alpha 2,8S-T gene was mainly expressed by neurons.

A reappraisal of ganglioside GD3 expression in the CNS

GD3 ganglioside is a major glycolipid component of the developing central nervous system but diminishes considerably as the CNS matures. Despite consistent biochemical data, the cellular localization of GD3 expression has been controversial. In this commentary we will review the cellular expression of GD3 during CNS development and in neuropathological circumstances as determined by studies with the two most commonly used anti GD3 monoclonal antibodies, R24 and LB1. GD3 is not restricted to any one cell lineage, being expressed in development to varying degrees by immature neuroectodermal cells, oligodendrocyte progenitors, ameboid microglia, and subpopulations of developing neurons and astrocytes. In the adult CNS, GD3 is expressed in low amounts by some neuronal subpopulations, on reactive and resting microglia, and by reactive astrocytes. In the appropriate contexts of development or neuropathology, anti-GD3 antibodies are useful for cell type identification and for cell isolation, but caution should be exercised because of the lack of cellular specificity.

The chemical constitution of gangliosides of the vertebrate nervous system

Glycosphingolipids are uniquely distinguished amongst the glycoconjugates by the apparently systematic structuring of their ceramide-linked carbohydrate moieties. These often highly complex oligosaccharides provide a structural repertoire that may vary considerably according to cell types and animal species. However, as a possible reflection of their specific functional role in the central nervous system, the brain glycosphingolipids of all vertebrates follow the same principles of carbohydrate structuring with only minor variations: the anabolically early addition of sialic acid to lactosylceramide (Gal beta 4Glc beta Cer-->NeuAc alpha 3Gal beta 4Glc beta Cer) in central nervous tissue results in the preferential formation of 'gangliosides', i.e., sialic acid-containing glycosphingolipids. Higher gangliosides result from extensions of sialo-lactosylceramide by addition of nucleotide-activated monosaccharides. In consequence, gangliosides of the vertebrate central nervous system consist of ceramide-linked sialo-oligosaccharides of varying chain length with a ganglio-series core carbohydrate, i.e., GalNAc beta 4Gal beta 3GalNAc beta 4Gal beta 4Glc beta < 0. Substitution by mono-, bis-, or tris-sialo-groups may variably be at the galactoside- and N-acetylgalactosaminide residues in 3- and 6-positions of the ganglio-series oligosaccharides, respectively. Ganglioside, which is derived by sialylation of galactosylceramide, NeuAc alpha 3Gal beta Cer, is a characteristic constituent of glial cells. In nerve tissue, gangliosides of the lacto-(Gal beta(3GlcNAc beta 3Gal beta)n4Glc beta <) and the neolacto-series (Gal beta(4GlcNAc beta 3Gal beta)n4Glc <) are more characteristic of vertebrate peripheral nerves and neuroectoderm-derived tumours. Recent studies using monoclonal antibodies have revealed that various single ganglioside components are specifically distributed in nervous tissues. This finding adds a new dimension to the earlier notion that gangliosides are involved in membrane related phenomena including cell to cell interactions, as well as, the modulation of signalling mechanisms.

Gangliosides and allied glycosphingolipids in human peripheral nerve and spinal cord

Glycosphingolipids were determined in human spinal cord, cauda equina and femoral nerve of 10 subjects aged 20-70 years and in dorsal and ventral roots of four subjects aged 17-60 years. Myelin was isolated from corresponding tissue. Axons were isolated from the four specimens of dorsal and ventral roots. The concentration (mean and standard error of mean) of gangliosides in spinal cord was 0.80 +/- 0.03 mumol sialic acid/g fresh tissue, in cauda equina 0.40 +/- 0.02 mumol/g and in femoral nerve 0.23 +/- 0.01 mumol/g. In spinal cord only trace amounts of glycosphingolipids of the lacto series were found, and the ganglioside pattern differed from that in cerebral white matter by a relatively high proportion of GD3 and a low proportion of GD1a. The ganglioside patterns were almost identical in cauda equina and femoral nerve--the major ganglioside being 3'-LM1, 0.07 and 0.04 mumol/g respectively. Another ganglioside of the lacto series, 3'-HexLM1, was 25% of 3'-LM1. Peripheral nerve also contained three acidic glycosphingolipids in addition to sulfatide--LK1 and HexLK1 belonging to the glycosphingolipid lacto series and containing glucuronyl-3-sulfate instead of sialic acid, and inositolphosphoryl galactosylceramide. The dorsal (sensory) and ventral (motor) roots had the same major membrane lipid composition but the ganglioside concentration was 30% higher in sensory than motor nerve and myelin. The patterns of gangliotetraose gangliosides were, however, the same in motor and sensory myelin and axons. The ceramide composition of the gangliosides is also reported.

A rapid method for the preparation of ganglioside Glac2 (GD3)

A method is described for the preparation of ganglioside Glac2 [(II3(NeuAc)2-LacCer, GD3] from cream of bovine milk using liquid-phase extraction with methanol or ethanol followed by anion exchange chromatography. The method is rapid and inexpensive; 1 kg cream, centrifuged from 14-15 L of bovine milk, yields approximately 70 mg of pure ganglioside Glac2. The sialic acid constituent of ganglioside Glac2 isolated from bovine milk cream consists solely of the N-acetylneuraminic acid derivative. The major components of its ceramide consist of octadecasphing-4-enine and the 22:0 (behenic acid) and 23:0 fatty acids.

Antitumor effects of a novel monoclonal antibody with high binding affinity to ganglioside GD3

Ganglioside GD3, which is one of the major gangliosides expressed on the cell surface human tumors of neuroectodermal origin, has been studied as a target molecule for passive immunotherapy. We established ten kinds of anti-GD3 monoclonal antibodies (mAb) of the mouse IgG3 subclass by immunization with purified GD3 and melanoma cells. One of the established mAb, KM641, showed major reactivity with GD3 and minor reactivity with GQ1b out of 11 common gangliosides in an enzyme-linked immunosorbent assay. Immunostaining of gangliosides, separated on thin-layer chromatography plates, using KM641 revealed that most of the melanoma cell lines contained immunoreactive GD3 and GD3-lactone at a high level, but only the adrenal gland and the urinary bladder out of 21 human normal tissues had immunoreactive GD3. In immunofluorescence, KM641 bound to a variety of living tumor cell lines especially melanoma cells, including some cell lines to which another anti-GD3 mAb R24, established previously, failed to bind. High-affinity binding of KM641 to a tumor cell line was quantified by Scatchard analysis (Kd = 1.9 x 10(-8) M). KM641 exerted tumor-killing activity in the presence of effector cells or complement against melanoma cells expressing GD3 at a high level. Not only natural killer cells but also polymorphonuclear cells were effective as the effector cells in antibody-dependent cellular cytotoxicity. Intravenous injection of KM641 markedly suppressed the tumor growth of a slightly positive cell line, C24.22 (7.2 x 10(5) binding sites/cell), as well as a very GD3-positive cell line, G361 (1.9 x 10(7) binding sites/cell), inoculated intradermally in nude mice. KM641, characterized by a high binding affinity for GD3, has the potential to be a useful agent for passive immunotherapy of human cancer.

Adult rat retina interneurons synthesize GD3: GD3 expression by these cells is regulated by cell-cell interactions

GD3, a ganglioside of the lactosyl series, is prevalent in rat retina neuronal cells. We studied here whether rat retina neurons synthesize their own surface GD3 or if they acquire it from Müller glia cells. We analyzed the activity of GD3 synthase and the in vivo labeling of gangliosides from N-[3H]acetylmannosamine in adult rat retinas after selective destruction of Müller glia cells with the gliotoxic alpha-D,L-aminoadipate (AAA). Immunostaining of rat retina sections and western blot analysis with an antivimentin antibody confirmed the gliotoxic effect of AAA. Neither GD3 synthase activity nor the in vivo labeling of GD3 and other gangliosides was significantly affected by AAA, indicating that neuronal cells synthesize their own GD3. We next analyzed the regulation of the expression of GD3 by these neurons in culture. About 80% of freshly dissociated cells from retina of 4-day-old rats (R4) immunoexpress surface GD3. After 3 days in dispersed cell culture conditions, GD3 expression was under the limit of detection in 80% of neuronal cells, indicating a failure of these cells to maintain the expression of surface GD3 in these experimental conditions. Most flat Müller glia-derived cells present in these cultures were GD3 positive. Surface GD3 was detected in approximately 60% of neuronal cells dissociated from R4 tissue that was developed in vitro as an organ culture for 3 days. Likewise, approximately 50% of neurites that had grown out from R4 retinal explants within 3 days in culture and whose neuronal character was indicated by immunoexpression of growth-associated protein GAP-43 were GD3 positive. These findings suggest that the tissue organization and/or specific interactions modulate GD3 expression in neuronal cells. Under dispersed-cell culture conditions, c-pathway gangliosides (GQ1c and GT1c), which are built up from the sialylation of GD3 and later completion of the oligosaccharide backbone, were detected in approximately 60% of neuronal cells, suggesting a maintenance of production of GD3 as an intermediate for gangliotetraosyl gangliosides.

Gangliosides in human fetal brain

The ganglioside concentration and composition were determined in 42 human fetal brains from gestational week 10 to 22, a period that is morphologically characterized by rapid neuroblast proliferation and migration. The ganglioside concentration was constant during this period, approximately 1 mumol of ganglioside sialic acid/g of fresh tissue weight. At gestational week 10 the ganglioside pattern was dominated by gangliosides of the ganglio b series, with the major ganglioside being GT1b, contributing 40% of total ganglioside sialic acid, whereas GD1b and GD3 contributed only 15 and 10%, respectively. The proportion of b series ganglioside decreased to gestational week 22, with the most pronounced relative reduction affecting GD3, but also GT1b and GD1b to a lesser extent. The ganglioside GQ1b increased in content from gestational week 10 and peaked around week 16. The proportion of GD1a increased markedly between gestational week 12 and 14 and slowly between week 14 and 18 and then increased rapidly from week 20. Ganglioside GM1 underwent a similar change. Gangliosides of the lacto series contributed 6-10% of ganglioside sialic acid between gestational week 10 and 15, and thereafter the proportion slowly decreased. 3'-isoLM1 decreased rapidly in content from gestational week 10 (20 nmol/g of fresh weight) to week 22 (less than 0.5 nmol/g of fresh weight), whereas the gangliosides of the neolacto series (3'-LM1 and 3',8'-LD1) showed a slower and less marked decline in level. The biological significance of the ganglioside changes is discussed.

A novel inositol-containing glycosphingolipid isolated from human peripheral nerve

An inositol-phosphate-containing glycosphingolipid, not reported earlier, was isolated from human cauda equina. Structural characterization showed the glycosphingolipid to be inositol-phosphoryl-2(3) galactosylceramide. The concentration varied between 25 and 30 nmol/g fresh tissue.

Role of gangliosides in active immunotherapy with melanoma vaccine

Among various tumor associated cell surface antigens, gangliosides, the glycosphingolipids that contain sialic acids, offer a variety of epitopes, some of which are preferentially expressed on melanoma cells. These surface components of the bilayered lipid membrane of tumor cells are the targets of active immunotherapy with melanoma vaccine. Purified gangliosides in aqueous solution form micelles and, at high density, form lactones. Their antigenic expression (physical conformation and orientation) on the cell surface is governed by the nature of the sphingosine and the fatty acids they contain. Evidence is accruing to show that the nature of the fatty acid moiety of gangliosides differs in normal and neoplastic cells. Gangliosides per se are not immunogenic and require extrinsic adjuvanticity. Preparation of a melanoma cell vaccine for active immunotherapy requires an understanding of the ganglioside profile of melanoma, the ganglioside-associated heterogeneity of melanoma, and the role of shed melanoma gangliosides in the immunosuppression of cell mediated and humoral immunity. In addition, the role of some of the anti-ganglioside antibodies in the elimination of shed gangliosides, the cytotoxic killing of tumor cells, as well as in the down-regulation of lymphocyte functions must be considered in the formulation of vaccine. Different strategies for augmenting the immunogenicity of melanoma associated gangliosides with melanoma vaccine are evaluated.

Glycolipids in rat cochlea

In recent years, the functions of glycolipids have been intensively studied. Before the research of the roles of glycolipids in the inner ear, it seemed to be necessary to demonstrate the composition of glycolipids at first. Therefore, rat cochlea has been examined for glycolipid composition in the present study. Glycolipids extracted from 200 cochlea samples were separated into neutral and acidic glycolipid fractions. Each fraction was analyzed by thin-layer chromatography. The neutral glycolipid was almost exclusively galactosylceramide (cerebroside) with trace amounts of globoside and unidentified glycolipids. In acidic glycolipids, sulfated galactosylceramide (cerebroside sulfate) was most abundant. Of the gangliosides (sialic acid-containing glycolipids), ganglioside GM3 (51.8%) was the predominant component, and GM2 (6.0%), GM1 (8.8%), GD3 (10.7%), GD1a (8.7%), GD1b (5.9%), and GT1b (3.6%) were also detected. In addition to these, rat cochlea also contained several, minor, unidentified gangliosides. This pattern of the cochlear acidic glycolipids is very similar to that of the renal acidic glycolipids. This finding seems to be very interesting when considering that the toxic side effects of aminoglycosides occur only in the kidney and the inner ear.

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.

Human brain gangliosides: developmental changes from early fetal stage to advanced age

The developmental profiles of the four major brain gangliosides, GM1, GD1a, GD1b, and GT1b, were examined in human frontal lobe covering the period from 10 fetal weeks to 80 years of age. The ganglioside concentration increased approx. 3-fold from the 10th gestational week to the age of about 5 years. Gangliosides GM1 and GD1a increased 12-15-fold during the same period. The most rapid increase of GM1 and GD1a occurred around term, during the period for dendrite arborization, outgrowth of axons and synaptogenesis. GT1b showed a quite different developmental curve. It was the major ganglioside during the 3rd to 5th gestational month, whereafter its concentration dropped rapidly to term, from which time the concentration then increased up to 50 years of age. Similar curves were found for the other gangliosides of the b-series, GD3, GD2, GD1b and GQ1b. Ganglioside 3'-isoLM1 was a characteristic early fetal ganglioside which dropped rapidly to the 5th gestational month, reached a small peak around term and then disappeared during adulthood. The concentration of gangliosides of the neolacto series was larger than that of the lacto series during the whole developmental period. In the beginning of the second trimester, 3'-LM1 constituted 2% and LD1 10% of total ganglioside sialic acid. The new findings demonstrate more dynamic changes of the ganglioside patterns during development than noted in previous studies.

Detection of gangliosides as N-glycolylneuraminic acid-specific tumor-associated Hanganutziu-Deicher antigen in human retinoblastoma cells

Gangliosides were shown to bear the tumor-associated N-glycolylneuraminic acid (NeuGc)-specific Hanganutziu-Deicher (HD) antigen expressed in human retinoblastoma cells. HD antigenic gangliosides were detected by thin-layer chromatography/enzyme-immunostaining using affinity-purified chicken antibody against GM3 containing NeuGc and horseradish peroxidase-conjugated anti-chicken IgG. One to four species of the antigenic gangliosides were detected from all of 4 cell lines, Y79, WERI-Rb1, TOTL1, and YK, as well as freshly cultured retinoblastoma cells and isolated tumor tissue. All cases contained GM3(NeuGc) as an HD antigen. No HD antigenic ganglioside was detected in normal retinal tissues by the same procedure.

The glycosphingolipids of human prostate tissue

Neutral glycolipids and gangliosides from surgical samples of benign human prostate tissue were analyzed by chemical, enzymatic and immunostaining procedures. The neutral glycolipids consisted of ceramide mono-, di-, tri- and tetrahexosides of the globo series plus paragloboside. The monosialoganglioside fraction contained GM3 and GM1 plus multiple species of monosialylated lactosamine-containing structures, including sialyl-alpha-2----3paragloboside plus at least two compounds having a non-reducing terminal sialyl alpha 2----6Gal linkage. The disialoganglioside fraction contained GD3 as the major component plus GD1a, GD2 and GD1b. GT1b was the major trisialoganglioside.

Host cell-induced differences in O-glycosylation of herpes simplex virus gC-1. I. Structures of nonsialylated HPA- and PNA-binding carbohydrates

Lectins with narrow oligosaccharide specificities were established as probes to study the host cell influence on the biosynthesis of O-linked oligosaccharides of the herpes simplex virus type 1 (HSV-1)-specified glycoprotein C (gC-1). We found that only gC-1 and no other glycoprotein bound to the peanut lectin (PNA), with main specificity for Gal(beta 1-3)GalNAc. Previously, we have shown that only gC-1 binds to the Helix pomatia lectin (HPA), with main specificity for terminal GalNAc. The O-linked oligosaccharides binding to PNA and HPA were released by alkaline borohydride treatment and characterized. A structural determination of these oligosaccharides showed that the HPA-binding carbohydrates were monosaccharides (GalNAc), and that the PNA-binding oligosaccharides were disaccharides with the structure Gal-GalNAc. The PNA- and HPA-binding oligosaccharides were arranged as Pronase-resistant clusters on gC-1, consisting of about seven individual, adjacent oligosaccharides. In addition to these disaccharides, Pronase-resistant PNA-binding glycopeptides of gC-1 also contained neutral trisaccharides. Larger O-linked oligosaccharides, binding to the wheat germ lectin, were found in gC-1, but not in proximity to the PNA-binding ones. It was concluded that the lectins mentioned should be useful probes in screening HSV-infected cells of different lineages for differences in processing of O-linked oligosaccharides.

Biosynthesis and expression of gangliosides during differentiation of chick embryo retina cells in vitro

Cells from neural retina from 7-day chick embryos were cultured on polylysine-coated dishes up to 7 days. The small, round-shaped cells at seeding differentiated progressively, and after 4 days in vitro the majority had enlarged bodies and abundant processes. The content of protein and DNA was essentially unchanged during the entire period of culture. The incorporation of radioactivity from [3H]glucosamine into gangliosides declined slightly, reaching about 65% of the initial values at the end of the culture period. The proliferating activity measured by the incorporation of [3H]thymidine into DNA decreased to 10% or less of the initial value after 3 days in vitro. Almost at the same chronological times as in ovo, the synthesis of GD3 and of a ganglioside partially identified as GT3 decreased from 70 and 19% of the total incorporation into gangliosides in the first 20 h of culture to about 7 and 5%, respectively, after 3 days in vitro. Conversely, the synthesis of GD1a increased from about 6% at the beginning to about 70% at the end of the culture times. Immunocytochemical analyses of the expression of gangliotetraosyl gangliosides in cultured cells showed that these gangliosides appeared in the bodies and processes of cells having neuronal morphology; very little immunostaining of the scarce flattened cells, probably Müller cells, was found. The results indicate that the changes in ganglioside metabolism, which lead to decreased synthesis of gangliosides lacking the galactosyl-N-acetyl-galactosaminyl disaccharide end and to increased synthesis of gangliotetraosyl gangliosides, occur in cells that in culture differentiate into neurons.

Large alterations in ganglioside and neutral glycosphingolipid patterns in brains from cases with infantile neuronal ceroid lipofuscinosis/polyunsaturated fatty acid lipidosis

Lipid composition was studied on cerebral tissue from nine children who had died of a progressive encephalopathy called the infantile form of neuronal ceroid lipofuscinosis (INCL) or polyunsaturated fatty acid lipidosis (PFAL). In the terminal stage of the disease, the concentrations of all lipid classes were found to be significantly reduced in the cerebral and cerebellar cortex and white matter. The concentration of gangliosides of the cerebral cortex was 15% and that of cerebrosides (galactosylceramide) in white matter 0.2-5% of the normal values for the children's ages. The reduction of gangliosides mainly affected those of the gangliotetraose series, particularly GD1a. The fatty acids of the linolenic acid series were strongly reduced in ethanolamine and serine phosphoglycerides. A very large increase up to 100-fold of oligoglycosphingolipids of the globo series and two fucose-containing lipids of the neolacto series was found in the forebrain of the three advanced cases examined. The brain tissue also contained very high concentrations of mono-, di-, and trisialogangliosides of the lacto and neolacto series, gangliosides with type 1 chain dominating. The structures of the gangliosides were tentatively identified by gas chromatography-mass spectrometry and monoclonal antibodies with carefully determined epitope specificity. The gangliosides and neutral glycosphingolipids had very similar fatty acid composition, consisting of about 40% stearic acid and 40% C24-acids.

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

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.

Gangliosides and neutral glycosphingolipids of normal tissue and oat cell carcinoma of human lung

Concentration and composition of gangliosides and neutral glycosphingolipids of adult human lung, and lung small cell carcinoma were studied. The structures of the glycolipids were determined by quantitative component determination, enzymic degradation, permethylation and fast atom bombardment mass spectrometry. Adult human lung contained mainly gangliosides with lactosylceramide as the basic core, GM3, GD3 and GT3, and approx. equal proportions (10%) of gangliosides of the gangliotetraosyl- and lactotetraosylceramide series. 18 gangliosides with different carbohydrate moieties were identified: four of them were only found in the tumor tissue. The adult human lung contained 85 nmol (77-120) gangliosides and 140 nmol neutral glycosphingolipids per g wet weight. Globoside was the major neutral glycolipid and there were only minor amounts of glycolipids of the lactotetraose series. In small cell carcinoma tissue the concentration of neutral glycosphingolipids was approximately twice as high than in normal lung tissue, and there was a markedly larger concentration of both lactosylceramide and glycolipids of the lactotetraose series and fucose derivatives of these. The concentration of gangliosides varied between 202 and 415 nmol per g wet weight. Compared to normal lung tissue, the tumor tissue had a lower proportion of GD3, and a higher proportion of complex gangliosides, and they contained five tumor-associated gangliosides: Fuc-GM1, Fuc-GD1b, 3'-LM1, Fuc-3'-LM1 and 6'-nLM1.

Characterization of new gangliosides of the lactotetraose series in murine xenografts of a human glioma cell line

The major mono- and disialogangliosides of the extensively characterized established human glioma line D54MG were isolated and purified from subcutaneous solid xenografts grown in athymic (nu/nu) mice. Structural determination showed that they belonged to the lactotetraosylceramide series. The sialyllactotetraosylceramide contained 90% N-glycolyl- and 10% N-acetylneuraminic acid linked in an alpha 2-3 linkage (IV3NeuGc-LcOse4Cer, IV3NeuAc-LcOse4Cer). The disialogangliosides had a previously undescribed type of structure with sialic acids linked to the terminal galactose in an alpha 2-3 linkage and to N-acetylglucosamine in an alpha 2-6 linkage. Not only did species with NeuAc or NeuGc occur, but also species with mixtures of the two sialic acids, e.g. NeuAc and NeuGc. The schematic structures of the new disialogangliosides are (Formula:see text).

Trisialosyllactosylceramide (GT3) is a ganglioside of human lung

A trisialoganglioside not found before in human tissue was isolated from showed this to be II3(NeuAc)3-LacCer or GT3. The ganglioside constituted 40% of the trisialogangliosides of human lung or 0.2 nmol ganglioside per g tissue.

Ganglioside GD3: structure, cellular distribution, and possible function

Insight on the function of gangliosides can emerge from knowledge of their cellular distribution. In this paper we review the structure of ganglioside GD3 and recent information on its cellular distribution. GD3 appears to be enriched in a variety of neural cell types including: reactive glia, gliomas, undifferentiated neurons, Muller glia, and oligodendroglia. Because each of these cell types share an enhanced permeability to ions and metabolites or possess properties associated with enhanced permeability, we suggest that GD3 is associated with enhanced membrane permeability. A possible function for GD3 in membrane permeability has implications for other cellular events such as metabolism, growth and interactions.

Gangliosides of human thyroid gland

The ganglioside composition of adult human thyroid gland was examined in autopsy material obtained from patients who died of circulatory diseases but who showed no signs of thyroid disorders. The concentrations of phospholipids, cholesterol and gangliosides (lipid-bound sialic acid) in the whole glands were 5.2, 4.3 and 0.12 mmol/kg fresh tissue weight and, in dissected follicular material, 7.0, 3.4 and 0.24 mmol/kg tissue, respectively. The molar ratio of phospholipids/cholesterol/gangliosides in the follicular material was 1.00:0.49:0.034. Twelve molecular species of gangliosides were isolated and identified. Gangliosides GM3 and GD3 were most abundant, but GD1a, GD1b, GT1b and 3'-LM1 were also present in quantities greater than 5% of the total gangliosides. N-Acetylneuraminic acid and an alkali labile sialic acid, probably N-acetyl-9-O-acetylneuraminic acid, were found to occur in human thyroid.

Chemical structure of carcinoma ganglioside antigens defined by monoclonal antibody C-50 and some allied gangliosides of human pancreatic adenocarcinoma

A hybridoma, C-50, obtained by fusion of mouse myeloma cells with spleen cells from a mouse immunized with cells from the colorectal carcinoma cell line COLO 205, produced antibodies that detected ganglioside antigen in human adenocarcinomas in many organs. The major ganglioside antigen fraction isolated from liver metastases of a pancreatic adenocarcinoma, behaving as a homogenous band on thin-layer chromatography, consisted of three different gangliosides. One of them, A (25%), had the same carbohydrate structure as the ganglioside antigen defined by monoclonal antibody 19-9, NeuAc alpha 2-3Gal beta 1-3(Fuc alpha 1-4)GlcNAc beta 1-3Gal beta 1-4Glc-Cer(Fuc-3'-isoLM1) Magnani, J.L., Nilsson, B., Brockhaus, M., Zopf, D., Steplewski, Z., Koprowski, H. and Ginsburg, V. (1982) J. Biol. Chem. 257, 14365-14369). The major ganglioside, B (60%), was the isomeric hexasaccharide ganglioside (NeuAc alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3-Gal beta 1-4Glc-Cer(Fuc-3'-LM1) and the third ganglioside, C, was 6'-LM1, NeuAc alpha 2-6Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc-Cer (15%). Ganglioside B, isolated from human kidney, did not react with the C-50 MAb. Based on this result and on studies of COLO 205 cell induced tumours where the ganglioside antigen fraction only consisted of A, it is suggested that the C-50 MAb defines an antigen determinant present in A.

Sialosyllactotetraosylceramide, a novel ganglioside antigen detected in human carcinomas by a monoclonal antibody

A novel ganglioside was detected in a small cell lung carcinoma by TLC-immunostaining of gangliosides with a monoclonal antibody, the C-50 MAb. Structural characterization showed this ganglioside to be IV3NeuAc-LcOse4Cer, a hitherto unknown ganglioside. This ganglioside has also been detected as a minor component in many different carcinomas using the C-50 MAb. The normally dominant CA-50 ganglioside antigen is IV3NeuAc, III4Fuc-LcOse4Cer. Based upon solid-phase binding to IV3NeuAc, III4-LcOse4Cer and IV3NeuAc-LcOse4Cer it is concluded that the C-50 MAb recognizes an epitope present in sialylated type I carbohydrate chains.

Spinal ganglia and peripheral nerves from a patent with Tay-Sachs disease. Morphological and ganglioside studies

We examined the spinal ganglia and peripheral nerves from a patient with Tay-Sachs disease, comparing the other nervous tissues morphologically and lipid-biochemically. The spinal ganglia and peripheral nerves showed numerous membranous cytoplasmic inclusion bodies (MCBs), which are characteristic of GM2-ganglioside storage in the neuronal cell bodies of the patient brains. In spinal ganglia, all neurons and satellite cells around the neurons contained membrane-bound lipid materials. In peripheral nerves, Schwann cells and myelinated axons except for enlarged axons were devoid of MCBs. Major ganglioside stored in both spinal ganglia and peripheral nerve was also GM2-ganglioside. The contents of ganglioside in the spinal ganglia and peripheral nerves were 50 and 10 times more than those from normal tissues, respectively. The spinal cord contained a slightly higher amount of gangliosides than the normal control. The cerebral white matter totally demyelinated in this patient accumulated a much higher amount of gangliosides than the cerebral gray matter. The retinal tissue showed GM2-ganglioside as the major one also.

Lipids of nervous tissue: composition and metabolism

As indicated in the Introduction, the many significant developments in the recent past in our knowledge of the lipids of the nervous system have been collated in this article. That there is a sustained interest in this field is evident from the rather long bibliography which is itself selective. Obviously, it is not possible to summarize a review in which the chemistry, distribution and metabolism of a great variety of lipids have been discussed. However, from the progress of research, some general conclusions may be drawn. The period of discovery of new lipids in the nervous system appears to be over. All the major lipid components have been discovered and a great deal is now known about their structure and metabolism. Analytical data on the lipid composition of the CNS are available for a number of species and such data on the major areas of the brain are also at hand but information on the various subregions is meagre. Such investigations may yet provide clues to the role of lipids in brain function. Compared to CNS, information on PNS is less adequate. Further research on PNS would be worthwhile as it is amenable for experimental manipulation and complex mechanisms such as myelination can be investigated in this tissue. There are reports correlating lipid constituents with the increased complexity in the organization of the nervous system during evolution. This line of investigation may prove useful. The basic aim of research on the lipids of the nervous tissue is to unravel their functional significance. Most of the hydrophobic moieties of the nervous tissue lipids are comprised of very long chain, highly unsaturated and in some cases hydroxylated residues, and recent studies have shown that each lipid class contains characteristic molecular species. Their contribution to the properties of neural membranes such as excitability remains to be elucidated. Similarly, a large proportion of the phospholipid molecules in the myelin membrane are ethanolamine plasmalogens and their importance in this membrane is not known. It is firmly established that phosphatidylinositol and possibly polyphosphoinositides are involved with events at the synapse during impulse propagation, but their precise role in molecular terms is not clear. Gangliosides, with their structural complexity and amphipathic nature, have been implicated in a number of biological events which include cellular recognition and acting as adjuncts at receptor sites. More recently, growth promoting and neuritogenic functions have been ascribed to gangliosides. These interesting properties of gangliosides wIll undoubtedly attract greater attention in the future.(ABSTRACT TRUNCATED AT 400 WORDS)

Biosynthesis of gangliosides in cultured retina from chick embryos

Retina tissue from 7-day chick embryos was maintained in culture for up to 10 days. After 5 days in culture the incorporation of [3H]leucine into proteins and of [3H]glucosamine into gangliosides was similar to that found in retinas from 12-day embryos. The incorporation of [3H]thymidine into DNA decreased steadily with time in culture; after 5 days it was about 20% of the initial value and approximately twice that determined in retinas from 12-day embryos. The radioactivity pattern of gangliosides labeled with [3H]glucosamine showed a predominance of the label in disialosyllactosylceramide (GD3); up to the 3rd day of culture. From then on, there was a progressive increase in the labeling of disialosylgangliotetraosylceramide (GD1a); by day 7 of culture, labeling of GD1a predominated and the labeling pattern was indistinguishable from that found in retinas from 12-day-old embryos. The specific activities of the CMP-NeuAc:GM3 sialosyl- and UDP-GalNAc:GM3 N-acetylgalactosaminyl-transferases decreased to 15% and increased to 400%, respectively, of the values determined in the retinas of 7-day embryos. The cultured retinas progressed in their organization into layers with culture time. The labeling transition from GD3 to GD1a was also detected after inhibition of the histotypic organization by addition of 5-bromo 2-deoxyuridine to the culture medium. Results suggest that high activity of GM3:sialosyl transferase and high labeling of GD3 are associated with the proliferative state of retina cells, while high activity of GM3:N-acetylgalactosaminyltransferase and high labeling of GD1a are associated with the non-proliferative, differentiated state of these cells.

The fine structure of cytoplasmic inclusions in brain and other visceral organs in Sandhoff disease

This paper describes an 11-month-old male who died of Sandhoff disease. Diagnosis was based on detection of cherry red spots and total deficiency of hexosaminidase A and B activities. Sections of the brain revealed swollen neuronal cells and their degeneration and disappearance, leaving a distorted cortical architecture. Ultrastructurally, numerous inclusions showing concentric lamellar or stacked lamellar profiles were found in ballooned neuronal cells, astrocytes and histiocytes. The parafoveal retina in the region of the cherry red spot contained ballooned ganglion and amacrine cells filled with PAS and LFB positive granules. Electron microscopically, these cells showed a greater accumulation of inclusions with stacked lamellar profiles, than the concentric lamellar ones, of classically membranous cytoplasmic bodies (MCB). Hepatocytes and Kupffer cells and epithelial cells of renal glomeruli contained pleomorphic inclusions. Biochemical analysis by thin-layer chromatography of lipid extracts from the cerebral cortex showed a marked increment of the GM2 fraction, without an increase in globoside.

Phylogeny and ontogeny of vertebrate brain gangliosides

Gangliosides evolved relatively recently in the history of life, thus their contribution to fundamental cellular processes must be ancillary to or superimposed on preexisting mechanisms. Brain ganglioside patterns vary along taxonomic lines in a fairly conservative fashion, indicating that general ecophysiological factors have probably provided the major selective constraints. During brain development in birds and mammals, gangliosides pass through a transient stage of pattern complexity that may reflect their reptilian ancestry. While this ganglioside heterogeneity could provide positional information within the developing tissue, it might merely reflect a necessary but incidental transition to the handful of major gangliosides essential to mature brain function.

Non-collagenous proteins of predentine from dentinogenically active bovine teeth

Predentin(e) was dissected out from unerupted permanent bovine teeth. The non-collagenous proteins were extracted at -13 degrees C by 4 M-guanidinium chloride containing proteinase inhibitors and separated by DEAE-Sepharose and Sephadex G-100 chromatography. In addition to a few minor constituents, the only major non-collagenous components that could be demonstrated were albumin and proteoglycan. The localization of the former, demonstrated by optical-microscopical immunochemistry, was such that it was concluded that albumin is not a constituent of predentin matrix. Very low amounts of phosphoprotein were found in predentin matrix. This was of two types, high- and low-phosphorylated. Larger amounts of phosphoprotein were not present until the dissection was carried deeper into newly formed dentin(e). On the basis of the present results and previously obtained morphological data the conclusion was drawn that predentin matrix, containing virtually only collagen type I and proteoglycan, is similar in composition to that of loose connective tissue and primarily aimed at the production and maturation of collagen fibres. Only immediately before the mineralization front are the non-collagenous protein components secreted that initiate and govern calcium-phosphate mineral formation.