Gangliosides in various brain areas of three inbred strains of mice

Ganglioside GM1 and the Central Nervous System

GM1 is one of the major glycosphingolipids (GSLs) on the cell surface in the central nervous system (CNS). Its expression level, distribution pattern, and lipid composition are dependent upon cell and tissue type, developmental stage, and disease state, which suggests a potentially broad spectrum of functions of GM1 in various neurological and neuropathological processes. The major focus of this review is the roles that GM1 plays in the development and activities of brains, such as cell differentiation, neuritogenesis, neuroregeneration, signal transducing, memory, and cognition, as well as the molecular basis and mechanisms for these functions. Overall, GM1 is protective for the CNS. Additionally, this review has also examined the relationships between GM1 and neurological disorders, such as Alzheimer's disease, Parkinson's disease, GM1 gangliosidosis, Huntington's disease, epilepsy and seizure, amyotrophic lateral sclerosis, depression, alcohol dependence, etc., and the functional roles and therapeutic applications of GM1 in these disorders. Finally, current obstacles that hinder more in-depth investigations and understanding of GM1 and the future directions in this field are discussed.

An assessment of the rescue action of resveratrol in parkin loss of function-induced oxidative stress in Drosophila melanogaster

Loss-of-function mutations in parkin is associated with onset of juvenile Parkinson's disease (PD). Resveratrol is a polyphenolic stilbene with neuroprotective activity. Here, we evaluated the rescue action of resveratrol in parkin mutant D. melanogaster. The control flies (w1118) received diet-containing 2% ethanol (vehicle), while the PD flies received diets-containing resveratrol (15, 30 and 60 mg/kg diet) for 21 days to assess survival rate. Consequently, similar treatments were carried out for 10 days to evaluate locomotor activity, oxidative stress and antioxidant markers. We also determined mRNA levels of Superoxide dismutase 1 (Sod1, an antioxidant gene) and ple, which encodes tyrosine hydroxylase, the rate-limiting step in dopamine synthesis. Our data showed that resveratrol improved survival rate and climbing activity of PD flies compared to untreated PD flies. Additionally, resveratrol protected against decreased activities of acetylcholinesterase and catalase and levels of non-protein thiols and total thiols displayed by PD flies. Moreover, resveratrol mitigated against parkin mutant-induced accumulations of hydrogen peroxide, nitric oxide and malondialdehyde. Resveratrol attenuated downregulation of ple and Sod1 and reduction in mitochondrial fluorescence intensity displayed by PD flies. Overall, resveratrol alleviated oxidative stress and locomotor deficit associated with parkin loss-of-function mutation and therefore might be useful for the management of PD.

GT1b ganglioside induces death of dopaminergic neurons in rat mesencephalic cultures

We examined neurotoxicity of GT1b against dopaminergic neurons in vitro. Cultures of mesencephalic cells deprived of serum underwent the loss of 19% of tyrosine hydroxylase immunopositive (TH-ip) neurons. In cultures deprived of serum, treatment with 10-30 microg/ml GT1b attenuated the number of TH-ip neurons by 26-69%, respectively, compared to non-treated cultures. Intriguingly, cultures deprived of serum were more vulnerable to GT1b-induced neurotoxicity. Application of 60 microg/ml GT1b to cultures grown in serum containing media resulted in the loss of 26% of TH-ip neurons, similar to that (28%) observed in serum-deprived cultures treated with 10 microg/ml GT1b. Moreover, in our cultures, absence of nitric oxide (NO) production after GT1b treatment was obvious. The present results strongly suggest direct neurotoxic actions of GT1b against dopaminergic neurons regardless of NO.

Developmental profiles of gangliosides in trisomy 19 mice

The ganglioside composition of the cerebrum, cerebellum, brainstem, liver, heart, and spleen was analyzed quantitatively in trisomy 19 (Ts19) mice aged 4 to 12 days postpartum. The developmental profiles of cerebral gangliosides were similar in Ts19 mice and control littermates: Total ganglioside-sialic acid as well as the proportions of the individual gangliosides GD1a and GM1 increased with age, while the percentages of GQ1b and GT1b decreased during development. Both the accretion of the total ganglioside content and the development of the individual ganglioside fractions were delayed by 2-3 days in the Ts19 telencephalon. Likewise, the shift from the b- to the a-pathway of ganglioside synthesis was retarded. Ganglioside development was equally delayed in the cerebellum and the brainstem of Ts19 mice. Since in Ts19 mice, morphogenesis of several brain regions is similarly delayed by 2 days, these results confirm the usefulness of gangliosides as biochemical markers for brain maturation. In contrast to brain gangliosides, the ganglioside composition of the Ts19 livers was clearly distinguished from that of control livers. Total ganglioside-bound sialic acid was increased by 35-50% in Ts19 livers. This elevation in ganglioside content not explicable by a simple delay in development was mainly due to an increase in GD3 and fraction 2, which is likely to contain GD1a and GD1b. In contrast, GM2 which increased considerably with age in control mice persisted on a low level in Ts19 livers. Comparable alterations of the ganglioside pattern were neither observed in the spleen nor in the heart of Ts19 mice. The data presented give additional evidence that ganglioside synthesis in the liver is under a different regulation mechanism than that in the brain, heart, and spleen.

Gangliosides of the mouse spinal cord: a comparison in in vivo and in vitro tissues

Ganglioside profiles in spinal cord from 13-day mouse fetuses, 21-day postnatal and adult mice were compared with those harvested from organotypic cross-sections of fetal mouse spinal cord grown for 28 days in vitro in a serum-free medium. All the major species of gangliosides reported for brain were present both in the in vivo tissue and cultured spinal cord, though not necessarily at each developmental stage examined. Fresh tissues showed increases and decreases in various gangliosides as have been reported for higher brain centers at similar stages of development in mammals and birds. However, qualitative and quantitative differences exist between fresh spinal cord and cultured cord explants as well as between galactose-grown and galactose-free cultures. Spinal cord explants grown in the presence of galactose showed measurable amounts of GM2 and GM3 which were not detected in the control-defined medium-grown cultures. The differences between the two culture groups may be related to interneuronal connectivity patterns.

Day-night cycle of lipidic composition in rat cerebral cortex

A study of the lipidic pattern of the cerebral cortex of the normal adult rat during the day-night cycle was carried out. The changes observed were the following: phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine plus phosphatidic acid showed a peak at 16:00 hr possibly due to a general increase in phospholipid biosynthesis. During the nocturnal period the variations of phosphatidylcholine and phosphatidylethanolamine were not clearly observed, they might be due to an increase in the interconversion or exchange reaction, since the ratio phosphatidylcholine/phosphatidylethanolamine showed a significative change at 04:00 hr. This occurred because small but opposite changes in both phospholipids were observed, suggesting an increase in the methylation reactions of phospholipids. Cardiolipin showed a significant peak at 04:00 hr. Plasmalogens exhibited significative changes, an important diminution at 16:00 hr and a prominent peak at 24:00 hr. Cholesterol levels were high during the light period and low in the dark one. Cerebrosides and gangliosides showed no day-night variations. The changes observed indicate a phenomenon of biological rhythmicity synchronized by the photoperiod, suggesting that these fluctuations could act as physiological modulators of the properties and functions of the nerve cell membrane.

Ganglioside patterns during cerebral development in the normal and reeler mouse

Gangliosides were extracted from cerebral tissue of reeler and normal mice, and analyzed by two-dimensional thin-layer chromatography at embryonic and postnatal ages. The ganglioside pattern changed substantially as development proceeded in the telencephalon of both reeler and normal mice, but was the same at any given age for both conditions, despite the marked histological differences between reeler and normal samples. These results indicate that abnormal ganglioside patterns do not result from the reeler mutation at early stages of brain development, and that the cell misalignment characteristic of the reeler phenotype involves molecules other than gangliosides.

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)

Substrate specificity and distribution of acid beta-galactosidase activities in seizure-susceptible and non-susceptible strains of mice

The properties and distribution of beta-galactosidase were studied in the mouse brain using the artificial substrate methylumbelliferyl-beta-galactoside. Enzyme activities were compared between an audiogenic seizure-susceptible mouse strain (DBA/2) and three non-susceptible strains of mice (BALB/c, C3H/He and Swiss A2G). At all ages, DBA/2 mice have significantly lower beta-galactosidase activity compared with the three other mouse strains: this is attributed to the different alleles present at the Bgs locus. The low activity of beta-galactosidase is also evident when the natural substrate GMl-ganglioside is hydrolyzed. In contrast to this low GMl-ganglioside-beta-galactosidase activity, there is no difference in the activity of the second form of acid beta-galactosidase, galactosylceramidase, in DBA/2 mice at 7 and 14 days. However, at 21 and 28 days the activity is significantly lower in DBA/2 mice compared with the other strains of mice. These results on beta-galactosidase activity in the brain of seizure-susceptible and non-susceptible mice are discussed in relation to published levels of GMl-ganglioside and galactosylceramide present in the developing mouse brain.

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.

Absence of ganglioside GM1 in astroglial cells from 21-day old rat brain: immunohistochemical, histochemical, and biochemical studies

A procedure was developed for the cultivation of cells derived from the cerebral hemispheres of the 21-day old rat. Approximately 98 percent of the cells in a 10 day culture are astrocytes that contain glial fibrillary acidic protein. Analysis of the extracted gangliosides by thin layer chromatography revealed that ganglioside GM1 was absent and that the predominant ganglioside was GM3. Very small amounts of the polysialogangliosides GD1a, GD1b, and GT1b were detected. The concentration of gangliosidic NeuNAc per mg protein in these astrocytes was only 3 percent that observed in the 5 day culture of a mixed cell preparation from newborn rat brain. Immunohistochemical and histochemical studies were performed on the mixed cell population of the minced tissue of 21-day old rat brain prior to cultivation. Astrocytes did not stain for hyaluronectin. These cells also did not provide a positive staining reaction for ganglioside GM1 utilizing the antiganglioside GM1 peroxidase-antiperoxidase procedure and the biotinylated choleragen-avidin-peroxidase procedure. These two histochemical methods for ganglioside GM1 also did not stain astrocytes that had been cultured for 5 days. Oligodendroglial cells, which were also present in the uncultured 21-day-old minced brain tissue, stained positively for ganglioside GM1 and hyaluronectin. Hyaluronectin had previously been shown to be a marker for oligodendroglia. Oligodendroglial cells which were present in the 5 day cultures of 21-day old brain tissue also provided a positive reaction for ganglioside GM1. It is concluded that ganglioside GM1 is absent in astroglia. The presence of small amounts of polysialogangliosides in the "pure" astrocyte preparation is discussed.

Differences in liver ganglioside patterns in various inbred strains of mice

The ganglioside patterns in the liver of different inbred and hybrid strains of mice were investigated. The inbred strains were Balb/cAnNCr1BR, C57BL/6NCr1BR, DBA/2NCr1BR. C3H/HeNCr1BR; the hybrid strain was the Swiss albino. The following major gangliosides were found to be present in mouse liver: GM3-NeuAc; GM3-NeuGl, GM2 [a mixture of one species carrying N-acetylneuraminic acid (NeuAc) and one carrying N-glycollylneuraminic acid (NeuGl)], GM1 and GD1a-(NeuAc,NeuGl). The qualitative and quantitative patterns of liver gangliosides were markedly different in the various inbred strains of mice; in Balb/cAnNCr1BR strain, ganglioside GM2 was preponderant (99.2% of total ganglioside content); in C57BL/6NCr1BR, the major ganglioside was GM2 (90.4%), followed by GM3-NeuAc (5.6%) and GM3-NeuGl (4.0%); in DBA/2NCr1BR, GM2 accounted for 77.1%, GD1a-(NeuAc,NeuGl) 18.9% and GM1 3.1% of gangliosides; in C3H/HeNCr1BR, GM2 constituted 50.6%, GM1 22.8% and GD1a-(NeuAc,NeuGl) 22.1%. In the hybrid Swiss albino mice, liver ganglioside composition markedly varied from one animal to another, GM3-NeuGl, GM2 and GD1a-(NeuAc,NeuGl) being the predominant gangliosides in the various cases.