GM1 ganglioside as a marker for neuronal differentiation in mouse cerebellum

Modifications of ganglioside composition in peripheral nerve of myelin deficient Trembler mutant mouse

Ganglioside distribution was studied in peripheral nerves of normal controls and those of Trembler mutant mouse with defect in Schwann cell differentiation and myelination. Neuraminic acid content was considerably decreased in the mutant. Ganglioside distribution as evaluated by densitometry of resorcinol positive spots on thin-layer chromatography revealed a major peak for GD1a in normal controls. In the mutant, the relative proportion was modified with qualitative modifications in the GD1a area and a tremendous increase in GM3 content. The relation with the intense Schwann cell proliferation observed in the mutant is discussed.

A correlation between the appearance and the evolution of tetanus toxin binding cells and neurogenesis

The ontogenesis of cells expressing surface membrane binding sites for tetanus toxin (Tt) was studied in the mouse nervous system. Cells were labeled shortly after the tissue dissociation and the toxin bound was revealed by immunofluorescence. In the brain, spinal cord and dorsal root ganglia the toxin binding cells (TBC) are found as of very early stages of nervous system organogenesis, i.e. at 10 days of gestation. There is a close temporal correlation between the pattern of emergence and accumulation of TBC and the known pattern of appearance of post-mitotic neurons in mouse cerebral cortex, cerebellum and spinal cord. The curves of TBC abundance as a function of fetal age in various nervous system areas are different. They show regional fluctuations in the proportion of TBC that reflect the cumulative changes in the dynamics of neuronal subpopulations. The results indicate that Tt can be used as an ontogenetically early marker of neuronal differentiation and that the acquisition of Tt receptors may represent one of the earliest detectable characteristics of the developing neurons.

Galactosyltransferase defects in reeler mouse brains

Galactosyltransferase activities were examined in the cerebellum, cerebral cortex, and brain stem of reeler and wild-type mice. Galactosyltransferase assays were optimal for all required substrates, linear with incubation time, and proportional to protein concentration. In brain areas affected by the reeler mutation (i.e., cerebral cortex and cerebellum), galactosylation of both endogenous and exogenous glycoprotein acceptors was greatly reduced in reeler relative to controls. On the other hand, glycosylation of endogenous glycolipids was low, and equal between reeler and wild-type. Galactosyltransferase activities were similar, though not identical, in reeler and wild-type brain stems, which are phenotypically normal in reeler mice. Glucosyltransferase, beta-galactosidase, beta-N-acetylglucosaminidase, acid phosphatase, and lactate dehydrogenase specific activities were all unaffected in reeler cerebella, while galactosyltransferase activity was 52% of control. Inhibition of either UDPgalactose hydrolysis or beta-galactosidase had no effect on galactosyltransferase activity. The spectrum or galactosyltransferase deficiencies in reeler suggests that this enzyme is associated with the development of young granule cells.

Nervous system-specific protein D2 associated with neurite outgrowth in nerve cell cultures

Dissociated cerebral cells from fetal rat brain were grown in culture for various periods. After 12 days in culture the nervous system-specific surface membrane protein D2 reached both maximal specific concentration and maximal amount. Moreover, most of this D2 protein was in the perinatal form with high electrophoretic mobility. The amount of perinatal D2 protein possibly followed the amount of neurites in this system. D2 protein was also found in 2 neuroblastoma C-1300 clones: Neuro 2a and NB 41A3. By addition of gangliosides, Neuro 2a cells could be induced to differentiate and form processes, and D2 protein was significantly increased. However, in both differentiated and undifferentiated neuroblastoma cells D2 protein was present in the adult form with slow electrophoretic mobility. NB 41A3 cells were unaffected by gangliosides and D2 protein was not changed. Thus ganglioside treatment of Neuro 2a tumor cells was followed by a cellular response only partly similar to developmental events concomitant to differentiation of primary cells.

Gangliosides associated with microsomal subfractions of brain: comparison with synaptic plasma membranes

To study ganglioside distribution within subcellular components and test the hypothesis that they are localized at the nerve ending, microsomes and synaptic plasma membranes were isolated from young adult rat brains and compared with respect to ganglioside composition. These were shown to be heterogeneous preparations by fractionation on a discontinuous sucrose gradient into subfractions which had differing ganglioside concentrations. The highest ganglioside concentrations occurred in membranes banding at the 0.8M/1.0M and 1.0M/1.3M interfaces for both microsomes and synaptic plasma membranes. These subfractions had closely similar ganglioside concentrations and pattern distributions. In addition, the kinetics of ganglioside labeling following administration of [3H]-glucosamine were similar for the two preparations. The fact that microsomal subfractions representing heterogeneous mixtures of brain cell membranes showed close similarity to synaptosomal plasma membranes argues against localization of gangliosides at the nerve ending. These results, together with other lines of evidence, support the concept that gangliosides are distributed over large portions of the neuron (and perhaps other brain cells). Data concerning the labeling of gangliosides in different microsomal subfractions indicated a movement of label over time from the more dense to the less dense membranes, as was also noted for the glycoproteins in the same subfractions. Specific radioactivity of the gangliosides increased relative to that of the glycoproteins with time.

A new brain cell surface glycoprotein identified by monoclonal antibody

Of 207 monoclonal antibodies produced against cultured mouse cerebellar cells, 16 reacted with cerebellar cell surfaces and 4 reacted with glycoproteins. One of them, called an anti-BSP-3 (Brain cell Surface Protein-3) defines a 48,000 molecular weight protein which can be iodinated at the surface of cultured cerebellar cells. Lectin-binding and sugar incorporation studies established the glycoprotein nature of the antigen. Astroglia (glial fibrillary acidic protein-positive cells) in primary cerebellar cultures were labelled intensely for this antigen by the indirect immunofluorescence method while neuronal cells and their processes were more weakly labelled. Fibronectin-positive cells were negative for BSP-3. In cerebellar sections using the immunoperoxidase method at both the optical and electron microscope levels, the difference in staining intensity between astrocytes and neuronal cells was not significant: in Purkinje cells and in the large neurones present in the deep cerebellar nuclei the immunoperoxidase percipitate was confined to the plasma, membrane while in both astrocytes and granule cells cytoplasmic labelling was also observed. Oligodendrocytes do not appear to react with the anti-BSP-3 monoclonal antibody; neither do endothelial or leptomeningeal cells. The availability of a monoclonal antibody produced by a stable hybridoma line will be a powerful tool in attempts to purify the BSP-3 antigen and to elucidate its function.

Expression of Thy-1, H-2, and NS-4 cell surface antigens and tetanus toxin receptors in early postnatal and adult mouse cerebellum

The expression of several cell surface components (Thy-1, H-2 and NS-4 antigens and tetanus toxin receptors) was studied by indirect immunofluorescence in situ using histological sections and in vitro using freshly dissociated and cultured cells from mouse cerebellum. Thy-1 alloantigen is expressed in adult cerebellum predominantly in neuron-rich regions, i.e. molecular, Purkinje cell, and granular layers, however, it is not detectable at postnatal day 8. In cerebellar cultures of 6-day-old mice Thy-1 is absent from more than 99% of all cells when these are maintained as monolayers in vitro for up to 3 days. After 4 days in vitro some GFA protein-positive astrocytes and some fibronectin-positive fibroblast-like cells start to express Thy-1 antigen. After 14 days in vitro not all fibroblast-like cells and astrocytes are Thy-1 antigen-positive. Neurons with small cell bodies and oligodendrocytes never express Thy-1 at any stage examined. H-2 is not expressed sufficiently to be detectable in histological sections in early postnatal or adult cerebellum. In cerebellar cultures of 6-day-old mice H-2 becomes detectable on some fibroblast-like cells and some astrocytes after 7 days in culture. In histological sections of adult and early postnatal cerebellum NS-4 antigen and tetanus toxin receptors are expressed at higher levels on more mature granule cells. In cerebellar cultures NS-4 antigen and tetanus toxin receptors are expressed on neurons. Occasionally some astroglia can also show detectable levels of expression. NS-4 antigen is also present on some 04 antigen-positive oligodendrocytes, while tetanus toxin receptors are never detectable on these cells.

Neuronal and glial cells in the superficial layers of early postnatal mouse neocortex: immunofluorescence observations

Sections of immature (postnatal day 5) mouse cerebral cortex was examined for several cell-type specific immunological markers. Glial fibrillary acidic (GFA) protein or vimentin were detected in astrocytic cell processes and--more rarely--cell bodies located in the superficial layers, but not within putative Cajal-Retzius cells (CRs). These cells did, however, react with cholera toxin, tetanus toxin and NS-4 antibodies. In agreement with previous ultrastructural observations, we conclude that CRs are neurons, or at least cells which display the basic characteristics of neurons.

Immunocytochemical demonstration of vimentin in astrocytes and ependymal cells of developing and adult mouse nervous system

The occurrence of vimentin, a specific intermediate filament protein, has been studied by immunoflourescence microscopy in tissue of adult and embryonic brain as well as in cell cultures from nervous tissue. By double imminofluorescence labeling, the distribution of vimentin has been compared with that of subunit proteins of other types of intermediate filaments (glial fibrillary acidic [GFA] protein, neurofilament protein, prekeratin) and other cell-type specific markers (fibronectin, tetanus toxin receptor, 04 antigen). In adult brain tissue, vimentin is found not only in fibroblasts and cells of larger blood vessels but also in ependymal cells and astrocytes. In embryonic brain tissue, vimentin is detectable as early as embryonic day 11, the earliest stage tested, and is located in radial fibers spanning the neural tube, in ventricular cells, and in blood vessels. At all stages tested, oligodendrocytes and neurons do not express detectable amounts of vimentin. In primary cultures of early postnatal mouse cerebellum, a coincident location of vimentin and GFA protein is seen in astrocytes, and both types of filament proteins are included in the perinuclear aggregates formed upon exposure of the cells to colcemid. In cerebellar cell cultures of embryonic-day-13 mice, vimentin is seen in various cell types of epithelioid or fibroblastlike morphology but is absent from cells expressing tetanus toxin receptors. Among these embryonic, vimentin-positive cells, a certain cell type reacting neither with tetanus toxin nor with antibodies to fibronectin or GFA protein has been tentatively identified as precursor to more mature astrocytes. The results show that, in the neuroectoderm, vimentin is a specific marker for astrocytes and ependymal cells. It is expressed in the mouse in astrocytes and glial precursors well before the onset of GFA protein expression and might therefore serve as an early marker of glial differentiation. Our results show that vimentin and GFA protein coexist in one cell type not only in primary cultures in vitro but also in the intact tissue in situ.

Recognition of Bergmann glial and ependymal cells in the mouse nervous system by monoclonal antibody

A monoclonal antibody designated anti-Cl was obtained from a hybridoma clone isolated from a fusion of NS1 myeloma with spleen cells from BALB/c mice injected with homogenate of white matter from bovine corpus callosum. In the adult mouse neuroectoderm, C1 antigen is detectable by indirect immunohistology in the processes of Bergmann glial cells (also called Golgi epithelial cells) in the cerebellum and of Müller cells in the retina, whereas other astrocytes that express glial fibrillary acidic protein in these brain areas are negative for C1. In addition, C1 antigen is expressed in most, if not all, ependymal cells and in large blood vessels, but not capillaries. In the developing, early postnatal cerebellum, C1 antigen is not confined to Bergmann glial and ependymal cells but is additionally present in astrocytes of presumptive white matter and Purkinje cell layer. In the embryonic neuroectoderm, C1 antigen is already expressed at day 10, the earliest stage tested so far. The antigen is distinguished in radially oriented structures in telencephalon, pons, pituitary anlage, and retina. Ventricular cells are not labeled by C1 antibody at this stage. C1 antigen is not detectable in astrocytes of adult or nearly adult cerebella from the neurological mutant mice staggerer, reeler, and weaver, but is present in ependymal cells and large blood vessels. C1 antigen is expressed not only in the intact animal but also in cultured cerebellar astrocytes and fibroblastlike cells. It is localized intracellularly.

Cholera-toxin binding to cells of developing chick retina analyzed by fluorescence-activated cell sorting

The occurrence of gangliosides on nerve cells of the developing retina was studied by fluorescence-activated cell analysis and sorting, using fluorescent cholera toxin as marker. This toxin binds to GM1; neuraminidase converts several other gangliosides into GM1. Without pretreatment by this enzyme weak binding of toxin is detected at later stages of development, whereas pretreatment leads to considerable toxin binding at earlier stages. The number of cells binding toxin as well as the amount bound per cell increase with developmental age of the retina. Cells binding a given amount of toxin vary strongly in size. Cell sorting was used to separate postmitotic cells from proliferating cells. Proliferating cells have little binding capacity, while postmitotic cells bind relatively large amounts of toxin. Localization of gangliosides which bind toxin in the developing retina was studied in cryostat sections. At an early stage (day 6) toxin binding is localized in the inner layer of the developing retina which contains the ganglion and other postmitotic cells, but is not found in the outer layer of matrix cells. At later stages complex staining patterns evolve with binding predominantly in the nerve fiber layers.

Neuronal differentiation in cultures of weaver (wv) mutant mouse cerebellum

In the present study we report for the first time a weaver (wv) gene dose effect on neuron survival and neurite formation in vitro. Dissociated cerebellar cells from postnatal 7- and 8-day-old normal (+/+), heterozygous weaver (+/wv) and homozygous weaver (wv/wv) mice were cultured as monolayers on poly-L-lysine coated glass. Cell death occurred rapidly in wv/wv cultures. Cell counts showed that less than 20% of the total neurons and neuronal precursors (identified by "birthday" radiolabeling techniques) survived by Day 3. Cell death was less extensive in +/wv cultures with 65% of the total neurons and 80% of the precursors surviving by Day 3. In contrast to wv/wv cultures, younger neurons survive better than the total population in +/wv cultures. The impairment of neurite formation over the first week is also proportional to the number of mutant genes as shown by quantitation of (a) the percentage of cells with neurites; (b) the percentage of cells with neurites of a given length class ith time; (c) the lengths of the longest process formed per cell. The mean longest neurite lengths obtained by computer digitization at 6 days in vitro were 41.8, 26.8, and 9.0 micron for +/+, +/wv, and wv/wv granule cells, respectively.

Surface proteins of cultured mouse cerebellar cells

Surface proteins of cultured monolayer cells from embryonic and early postnatal C57BL/6J mouse cerebella were identified by a lactoperoxidase-catalysed 131iodine labelling technique. Major iodinated polypeptides have molecular weights of approximately 200, 145, 120, 100, 85, 65, 50, and 30 x 10(3) (P200, P145,...) as estimated by sodium dodecylsulphate polyacrylamide gel electrophoresis. Membrane glycoproteins, of apparent molecular weights 200, 145, 100, 85, and 50 x 10(3), are detected by biosynthetic labelling with [3H]fucose. The two major iodinated proteins are the glycoproteins P200 and P145. P145 is released from the cells into the medium together with other surface proteins. No changes in the patterns of labelled cerebellar cell surface proteins are detectable between embryonic day 17 and postnatal day 10. A pattern similar to the one seen with cerebellum is obtained with embryonic day 12 and 17 cerebral cortex. Cultured retinal cells from 2-day-old mice, skin fibroblasts, and L-cells display a distinctly different pattern, which does not contain P145 as a major iodinated component. In granule cell-enriched fractions of cerebellar cells the two glycoproteins P200 and P145 are proportionately increased, while three proteins, P100, P85, and P50, are more abundant in the glial cell-enriched fraction. These three polypeptides are also enriched in cells obtained from staggerer mutant mice. An antiserum against 4-day-old cerebellar cells (anti-NS-4) precipitates the 145 and 200 x 10(3) molecular weight proteins, from lysates of both embryonic cerebral and postnatal cerebellar cells. From lysates of mouse retinal cells, anti-NS-4 antiserum precipitates two proteins with molecular weights of 140 and 210 x 10(3).