The role of receptor for advanced glycation end products (RAGE) in neuronal differentiation.
ABSTRACT The receptor for advanced glycation end products (RAGE) is a multiligand receptor protein thought to play an important role in neuronal differentiation. RAGE can bind a number of ligands and activate a variety of signalling pathways that lead to diverse downstream effects. Amphoterin and S100B are endogenous ligands, the interaction of which with RAGE is known to be involved in defined physiological processes. The present study investigated the spatiotemporal pattern of the expression for RAGE and its ligands, amphoterin and S100B, during neuronal differentiation of NT2/D1 cells. In this study, all three proteins were shown to increase with progression of neuronal differentiation as determined by Western blotting, raising the possibility that both amphoterin and S100B may interact with RAGE and have important functions during the process of cell differentiation. Moreover, blocking the activation of RAGE with neutralizing antibody in the presence of retinoic acid disrupted the progression of normal neuronal differentiation. Immunocytochemistry (ICC) studies showed that amphoterin partially colocalized with RAGE within differentiating NT2 cells, whereas S100B showed a high degree of colocalization. This result suggests that S100B is more likely to be the principal ligand for RAGE during the differentiation process and that RAGE and amphoterin might have both independent and combined roles. Moreover, RAGE was expressed only in cells that were committed to a neuronal phenotype, suggesting direct involvement of RAGE in mediating cellular changes within differentiating neuronal cells. Further detailed studies are now required to characterize fully the role of RAGE during the neuronal differentiation period.
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ABSTRACT: Sulfoglucuronyl carbohydrate (SGC) is expressed on several glycoproteins of the immunoglobulin superfamily of cell-adhesion molecules. Developmental expression of SGC and its binding protein, SBP-1, was studied in the rat cerebellum by immunocytochemistry to understand the function of SBP-1 and the significance of its interaction with SGC. During early postnatal development (postnatal day (PD) 3-10) SBP-1 was strongly expressed in the granule neurons of the external and internal granule cell layers (EGCL and IGCL). This expression declined by PD 15, and disappeared in the adult. Between PD 3 and 15, SGC was expressed in cellular processes surrounding the granule neurons in the IGCL, and it also declined and disappeared with development. SGC expression, however, continued in Purkinje cells and their dendrites in the molecular layer in adults. The expressions of SBP-1 and SGC were developmentally regulated and appeared to be chronologically co-ordinated with granule neuron migration from EGCL to IGCL. High magnification confocal microscopy showed that SBP-1 was primarily localized in nuclei and plasma membranes of granule neurons, whereas SGC in the IGCL was localized on neuronal plasma membranes, dendrites and glial processes, but not in cell soma. The relative localization of SBP and SGC was confirmed by cellular and subcellular markers in vivo and with dissociated cerebellar cells in culture. It is proposed that SBP-1 on plasma membranes of granule neurons interacts with SGC on the surrounding processes and membranes and this interaction could provide a potential mechanism for guidance and cell signaling, in the processes of granule neuron migration and differentiation.Developmental Brain Research 05/2000; 120(2):165-80. · 1.78 Impact Factor
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ABSTRACT: We used polyclonal antisera recognizing S100, a small acidic protein highly enriched in nervous tissue, to stain sections of embryonic chicken lumbosacral spinal cord and hindlimb. S100 immunoreactivity was detected in developing sensory neurons of the dorsal root ganglia (DRG) and motor neurons of the ventral spinal cord as early as embryonic day (E) 5, and staining persisted through hatching. In contrast, expression of S100 first became apparent in Schwann cells at E13, just before myelination, and was not detected in developing skin or muscle. Since S100 beta was present in motor and sensory neurons and is known to promote neuronal survival and neurite extension in vitro (Winningham-Major, Staecker, Barger, Coats, and Van Eldik, 1989), we tested the ability of S100 to promote neuron survival in an in ovo survival assay. Addition of S100 to chick embryos in ovo during the period of naturally occurring motor neuron cell death resulted in a significant increase in motor neuron survival, but had no effect on the in vivo survival of sensory neurons in the DRG. The findings that S100 is present in spinal motor neurons and that the addition of S100 enhances the survival of these cells in vivo are consistent with the possibility that S100 may act as a naturally occurring neuron survival factor during development.Journal of Neurobiology 07/1992; 23(4):451-66. · 3.05 Impact Factor
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ABSTRACT: We describe a nonradioactive preembedding in situ hybridization protocol using digoxigenin-labeled RNA probes and tyramide signal amplification to increase the sensitivity of detection. The protocol is sensitive enough for electron microscopic localization of endogenous messenger RNAs encoding beta-actin and amphoterin. Three visualization methods were compared: diaminobenzidine enhanced by nickel, Nanogold enhanced by silver and gold toning, and fluorescently labeled tyramides. Diaminobenzidine and Nanogold can be used in both light and electron microscopy. The nickel-enhanced diaminobenzidine was the most sensitive visualization method. It is easy to accomplish but a drawback is poor spatial resolution, which restricts its use at high magnifications. Nanogold visualization has considerably better spatial resolution and is therefore recommended for electron microscopy. Fluorescent tyramides, especially TRITC-tyramide, offer a good detection method for fluorescence and confocal microscopy. The methods were used to localize amphoterin and beta-actin mRNAs in motile cells. Both mRNAs were found in the soma and cell processes. In double labeling experiments, beta-actin mRNA localized to filamentous structures that also contained ribosomal proteins. Especially in the cortical cytoplasm, beta-actin mRNA was associated with actin filaments. Direct localization to microtubules was only rarely seen. (J Histochem Cytochem 47:99-112, 1999)Journal of Histochemistry and Cytochemistry 02/1999; 47(1):99-112. · 2.26 Impact Factor