Sialic acid metabolism is involved in the regulation of gene expression during neuronal differentiation of PC12 cells

Abstract

Sialic acid precursors are mediators of the sialic acid pathway. In this manuscript we present evidence that the application of sialic acid a precursor modulates gene expression and cell differentiation. The concept that sugars are involved in cellular transcription was first proposed by Jacob and Monod nearly 40 years ago studying the regulation of the lac-operon in prokaryotes. Surprisingly, these findings have never been transferred to eukaryotic systems. For our studies we have chosen PC12 cells. PC12-cells differentiate after application of NGF into a neuron-like phenotype. It is shown that treatment of PC12 cells with two different sialic acid precursors N-acetyl- or N-propanoylmannosamine, without application of NGF also induces neurite outgrowth. Moreover, the PC12 cells show the same morphology as the NGF-treated cells. Surprisingly, after application of both sialic acid precursors the phosphorylation and translocation of erk1/2 into the nucleus are activated, thus influencing the expression of genes involved in the differentiation of cells, such as the transcription factor c-Jun or TOAD-64/Ulip/CRMP (Turned ON After Division, 64 kd/ unc-33-like phosphoprotein/Collapsin Response Mediator Protein). These are the first experimental data showing that the sialic acid metabolism is closely associated with signal transduction and regulation of neuronal differentiation.

Tissue-based metabolic labeling of polysialic acids in living primary hippocampal neurons

“…For example, twofold increase in the Ac 4 ManNAz concentration (100 μM) abrogated the neuritogenesis completely, and no neurites were observed, whereas the fluorescence intensity was proportional to the Ac 4 ManNAz concentration as expected. This result might be on the same line with a recent finding that PC12 cells developed neurites with treatment of ManNProp or ManNAc (5 mM; 120 h) in the absence of nerve growth factor, presumably implying the involvement of sialic acid metabolism in gene expression and cell differentiation, although the phenotypic consequences were opposite to each other (44,45). Whereas ManNProp induced the neurite outgrowth of neuron-like PC12 cells, Ac 4 ManNAz suppressed the neurite outgrowth of primary hippocampal neurons.…”

Chemical Biology of Cell Surface Oligosaccharides

“…These off-target effects are exemplified by the already-mentioned ability of ManNProp to modulate mRNA levels of integrins [46], an observation that supports recent observations that simple sugars used as MOE analogs can function as signaling molecules involved in gene regulation [70]. Of note, efforts to increase the metabolic efficiency of analog uptake through SCFA modifications (Fig.…”

Quantum Dots with Phenylboronic Acid Tags for Specific Labeling of Sialic Acids on Living Cells

“…Our results have shown that the use of PBA-functionalized QDs enables one-step labeling and continuous tracking of the cell surface SA moieties of untreated living PC12 cells, which are neuroendocrine cells with abundant SA on their cell membranes mediating various cell functions such as cell adhesion, differentiation, and secretion. [25][26][27][28] The one-step procedure with fast kinetics and the biocompatibility of these QDs make it an ideal noninvasive technology for living cell imaging. The specificity of QD binding is confirmed by the competitive assay with free SA and staining of cells treated with sialidase, which removes the SA moiety from glycans ( Figure 1c).…”