We have identified a cell type in 7-day-old rat optic nerve that differentiates into a fibrous astrocyte if cultured in the presence of fetal calf serum and into an oligodendrocyte if cultured in the absence of serum. In certain culture conditions some of these cells acquire a mixed phenotype, displaying properties of both astrocytes and oligodendrocytes. These observations suggest that fibrous astrocytes and oligodendrocytes develop from a common progenitor cell and provide a striking example of developmental plasticity and environmental influence in the differentiation of CNS glial cells.

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Proton nuclear magnetic resonance (1H NMR) spectroscopy is a noninvasive technique that can provide information on a wide range of metabolites. Marked abnormalities of 1H NMR brain spectra have been reported in patients with neurological disorders, but their neurochemical implications may be difficult to appreciate because NMR data are obtained from heterogeneous tissue regions composed of several cell populations. The purpose of this study was to examine the 1H NMR profile of major neural cell types. This information may be helpful in understanding the metabolic abnormalities detected by 1H NMR spectroscopy. Extracts of cultured cerebellar granule neurons, cortical astrocytes, oligodendrocyte-type 2 astrocyte (O-2A) progenitor cells, oligodendrocytes, and meningeal cells were analyzed. The purity of the cultured cells was > 95% with all the cell lineages, except for neurons (approximately 90%). Although several constituents (creatine, choline-containing compounds, lactate, acetate, succinate, alanine, glutamate) were ubiquitously detectable with 1H NMR, each cell type had distinctive qualitative and/or quantitative features. Our most unexpected finding was a large amount of N-acetyl-aspartate (NAA) in O-2A progenitors. This compound, consistently detected by 1H NMR in vivo, was previously thought to ne present only in neurons. The finding that meningeal cells have an alanine:creatine ratio three to four times higher than astrocytes, neurons, or oligodendrocytes is in agreement with observations that meningiomas express a higher alanine:creatine ratio than gliomas. The data suggest that each individual cell type has a characteristic metabolic pattern that can be discriminated by 1H NMR, even by looking at only a few metabolites (e.g., NAA, glycine, beta-hydroxybutyrate).(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on cell lines have greatly improved our understanding of many important biological questions.

We have generated a hybridoma cell line secreting a monoclonal antibody that specifically binds to the surfaces of oligodendrocytes and Schwann cells, the cells involved in myelin formation in the central and peripheral nervous systems, respectively. Binding studies using purified sphingolipids showed that this antibody reacts strongly with galactocerebroside (GalC), the major galactosphingolipid of myelin. The antibody was used in conjunction with rabbit antisera against sulfatide, the sulfated form of GalC, to examine the developmental appearance of these lipids on the surfaces of oligodendrocytes and Schwann cells. In addition, the loss of GalC and sulfatide from freshly dissociated Schwann cells was compared. These studies showed that GalC is expressed on the cell surface prior to sulfatide on both of these cell types in vivo and in vitro. Conversely, dissociated Schwann cells lose their cell surface sulfatide more rapidly than they lose their surface GalC under nonmyelinating conditions. Certain lipids and proteins are thought to be predominantly found in myelin (1). Among these are the galactosphingolipids, galactocerebroside (GalC) and sulfatide. Despite their myelin association, the relationship of these lipids to the development ofoligodendrocytes and Schwann cells (the myelin-forming cells ofthe central and peripheral nervous systems, respectively) has not been studied on a cellular level in detail. Previous work, using either chemical analysis of extracted lipid or radiotracer studies, has described the developmental appearance ofmyelinspecific components in the nervous system (2). However, the techniques used were unable to establish the sequence in which components appear in individual cells or to resolve when such lipids are first inserted into the plasma membrane. Given that these lipids may play a role in the neuronal-glial interaction that results in myelination (3), it is important to ascertain their exact sequence and onset of appearance.One method that allows developmental studies on a cellular level is immunohistochemical labeling of cells with specific, characterized antisera. It has been established that in culture, polyclonal antisera against GalC and sulfatide specifically stain oligodendrocytes and Schwann cells (4). However, such work has suffered from the difficulty of adequately characterizing such antisera, which are often of low titer and questionable specificity.In the present study, we describe a hybridoma cell line that produces a monoclonal antibody binding specifically to the surfaces of oligodendrocytes and Schwann cells. A modification to existing enzyme-linked immunosorbent assay (ELISA) techniques was developed that allows the characterization of antibodies to lipid determinants. With this assay, the monoclonal antibody was shown to have a high specificity for GalC and, consequently, was designated mGalC. Various polyclonal rabbit antisera were similarly characterized and shown to bind to either GaiC or sulfatide. We used mGalC and rabbit antisera in double-labeli...