Ganglioside analysis by high-performance thin-layer chromatography

Lipid rafts mediate multilineage differentiation of human dental pulp-derived stem cells (DPSCs)

Cell outer membranes contain glycosphingolipids and protein receptors, which are integrated into glycoprotein domains, known as lipid rafts, which are involved in a variety of cellular processes, including receptor-mediated signal transduction and cellular differentiation process. In this study, we analyzed the lipidic composition of human Dental Pulp-Derived Stem Cells (DPSCs), and the role of lipid rafts during the multilineage differentiation process. The relative quantification of lipid metabolites in the organic fraction of DPSCs, performed by Nuclear Magnetic Resonance (NMR) spectroscopy, showed that mono-unsaturated fatty acids (MUFAs) were the most representative species in the total pool of acyl chains, compared to polyunsatured fatty acids (PUFAs). In addition, the stimulation of DPSCs with different culture media induces a multilineage differentiation process, determining changes in the gangliosides pattern. To understand the functional role of lipid rafts during multilineage differentiation, DPSCs were pretreated with a typical lipid raft affecting agent (MβCD). Subsequently, DPSCs were inducted to differentiate into osteoblast, chondroblast and adipoblast cells with specific media. We observed that raft-affecting agent MβCD prevented AKT activation and the expression of lineage-specific mRNA such as OSX, PPARγ2, and SOX9 during multilineage differentiation. Moreover, this compound significantly prevented the tri-lineage differentiation induced by specific stimuli, indicating that lipid raft integrity is essential for DPSCs differentiation. These results suggest that lipid rafts alteration may affect the signaling pathway activated, preventing multilineage differentiation.

GM1 Ganglioside Promotes Osteogenic Differentiation of Human Tendon Stem Cells

Gangliosides, the sialic acid-conjugated glycosphingolipids present in the lipid rafts, have been recognized as important regulators of cell proliferation, migration, and apoptosis. Due to their peculiar localization in the cell membrane, they modulate the activity of several key cell receptors, and increasing evidence supports their involvement also in stem cell differentiation. In this context, herein we report the role played by the ganglioside GM1 in the osteogenic differentiation of human tendon stem cells (hTSCs). In particular, we found an increase of GM1 levels during osteogenesis that is instrumental for driving the process. In fact, supplementation of the ganglioside in the medium significantly increased the osteogenic differentiation capability of hTSCs. Mechanistically, we found that GM1 supplementation caused a reduction in the phosphorylation of the platelet-derived growth factor receptor-β (PDGFR-β), which is a known inhibitor of osteogenic commitment. These results were further corroborated by the observation that GM1 supplementation was able to revert the inhibitory effects on osteogenesis when the process was inhibited with exogenous PDGF.

Coupling of In Vitro Bioassays with Planar Chromatography in Effect-Directed Analysis

Modern analytical test methods increasingly detect anthropogenic organic substances and their transformation products in water samples and in the environment. The presence of these compounds might pose a risk to the aquatic environment. To determine a possible (eco)toxicological risk, aquatic samples are tested using various bioassays, including sub-organismic assays such as the luminescent bacteria inhibition test, the acetylcholinesterase inhibition test, and the umu-test. The effect-directed analysis (EDA) combines physicochemical separation methods with biological (in vitro) tests. High-performance thin-layer chromatography (HPTLC) has proved to be particularly well suited for the separation of organic compounds and the subsequent analysis of effects by the application of the biotests directly on the surface of the HPTLC plate. The advantage of using HPTLC in comparison to high-performance liquid chromatography (HPLC) for EDA is that the solvent which is used as a mobile phase during chromatography is completely evaporated after the separation and therefore can no longer influence the applied bioassays.A prioritization during the complex identification process can be achieved when observed effects are associated with the separated zones in HPTLC. This increases the probability of identifying the substance responsible for an adverse effect from the multitude of organic trace substances in environmental samples. Furthermore, by comparing the pattern of biological effects of a separated sample, it is possible to track and assess changes in biological activity over time, over space, or in the course of a process, even without identifying the substance. HPTLC has already been coupled with various bioassays.Because HPTLC is a very flexible system, various detection techniques can be used and combined. In addition to the UV/Vis absorption and fluorescence measurements, TLC can also be coupled with a mass spectrometer (MS) for compound identification. In addition, detection of functional groups by means of derivatization reagents can support this identification. It is also possible to combine derivatization and HPLC-MS.Two case studies are used to illustrate the significance of HPTLC-EDA in investigating water quality: Study on a wastewater treatment plant Possible influence of an artificial turf surface on ground water.

Defective macroautophagic turnover of brain lipids in the TgCRND8 Alzheimer mouse model: prevention by correcting lysosomal proteolytic deficits

Autophagy, the major lysosomal pathway for the turnover of intracellular organelles is markedly impaired in neurons in Alzheimer's disease and Alzheimer mouse models. We have previously reported that severe lysosomal and amyloid neuropathology and associated cognitive deficits in the TgCRND8 Alzheimer mouse model can be ameliorated by restoring lysosomal proteolytic capacity and autophagy flux via genetic deletion of the lysosomal protease inhibitor, cystatin B. Here we present evidence that macroautophagy is a significant pathway for lipid turnover, which is defective in TgCRND8 brain where lipids accumulate as membranous structures and lipid droplets within giant neuronal autolysosomes. Levels of multiple lipid species including several sphingolipids (ceramide, ganglioside GM3, GM2, GM1, GD3 and GD1a), cardiolipin, cholesterol and cholesteryl esters are elevated in autophagic vacuole fractions and lysosomes isolated from TgCRND8 brain. Lipids are localized in autophagosomes and autolysosomes by double immunofluorescence analyses in wild-type mice and colocalization is increased in TgCRND8 mice where abnormally abundant GM2 ganglioside-positive granules are detected in neuronal lysosomes. Cystatin B deletion in TgCRND8 significantly reduces the number of GM2-positive granules and lowers the levels of GM2 and GM3 in lysosomes, decreases lipofuscin-related autofluorescence, and eliminates giant lipid-containing autolysosomes while increasing numbers of normal-sized autolysosomes/lysosomes with reduced content of undigested components. These findings have identified macroautophagy as a previously unappreciated route for delivering membrane lipids to lysosomes for turnover, a function that has so far been considered to be mediated exclusively through the endocytic pathway, and revealed that autophagic-lysosomal dysfunction in TgCRND8 brain impedes lysosomal turnover of lipids as well as proteins. The amelioration of lipid accumulation in TgCRND8 by removing cystatin B inhibition on lysosomal proteases suggests that enhancing lysosomal proteolysis improves the overall environment of the lysosome and its clearance functions, which may be possibly relevant to a broader range of lysosomal disorders beyond Alzheimer's disease.

Gangliosides as a potential new class of stem cell markers: the case of GD1a in human bone marrow mesenchymal stem cells

Owing to their exposure on the cell surface and the possibility of being directly recognized with specific antibodies, glycosphingolipids have aroused great interest in the field of stem cell biology. In the search for specific markers of the differentiation of human bone marrow mesenchymal stem cells (hBMSCs) toward osteoblasts, we studied their glycosphingolipid pattern, with particular attention to gangliosides. After lipid extraction and fractionation, gangliosides, metabolically (3)H-labeled in the sphingosine moiety, were separated by high-performance TLC and chemically characterized by MALDI MS. Upon induction of osteogenic differentiation, a 3-fold increase of ganglioside GD1a was observed. Therefore, the hypothesis of GD1a involvement in hBMSCs commitment toward the osteogenic phenotype was tested by comparison of the osteogenic propensity of GD1a-highly expressing versus GD1a-low expressing hBMSCs and direct addition of GD1a in the differentiation medium. It was found that either the high expression of GD1a in hBMSCs or the addition of GD1a in the differentiation medium favored osteogenesis, providing a remarkable increase of alkaline phosphatase. It was also observed that ganglioside GD2, although detectable in hBMSCs by immunohistochemistry with an anti-GD2 antibody, could not be recognized by chemical analysis, likely reflecting a case, not uncommon, of molecular mimicry.

Quantitative analysis of gangliosides in bovine milk and colostrum-based dairy products by ultrahigh performance liquid chromatography-tandem mass spectrometry

Milk gangliosides have gained considerable attention because they participate in diverse biological processes, including neural development, pathogen binding, and activation of the immune system. Herein, we present a quantitative measurement of the gangliosides present in bovine milk and other dairy products and byproducts. Ultrahigh performance liquid chromatography separation was used for high-throughput analysis and achieved a short running time without sacrificing chromatographic resolution. Dynamic multiple reaction monitoring was conducted for 12 transitions for GM3 and 12 transitions for GD3. Transitions to sialic acid fragments (m/z 290.1) were chosen for the quantitation. There was a considerable amount of gangliosides in day 2 milk (GM3, 0.98 mg/L; GD3, 15.2 mg/L) which dramatically decreased at day 15 and day 90. GM3 and GD3 were also analyzed in pooled colostrum, colostrum cream, colostrum butter, and colostrum buttermilk. The separation and analytical approaches here proposed could be integrated into the dairy industry processing adding value to side-streams.

Elevation of GM2 ganglioside during ethanol-induced apoptotic neurodegeneration in the developing mouse brain

GM2 ganglioside in the brain increased during ethanol-induced acute apoptotic neurodegeneration in 7-day-old mice. A small but a significant increase observed 2 h after ethanol exposure was followed by a marked increase around 24 h. Subcellular fractionation of the brain 24 h after ethanol treatment indicated that GM2 increased in synaptic and non-synaptic mitochondrial fractions as well as in a lysosome-enriched fraction characteristic to the ethanol-exposed brain. Immunohistochemical staining of GM2 in the ethanol-treated brain showed strong punctate staining mainly in activated microglia, in which it partially overlapped with staining for LAMP1, a late endosomal/lysosomal marker. Also, there was weaker neuronal staining, which partially co-localized with complex IV, a mitochondrial marker, and was augmented in cleaved caspase 3-positive neurons. In contrast, the control brain showed only faint and diffuse GM2 staining in neurons. Incubation of isolated brain mitochondria with GM2 in vitro induced cytochrome c release in a manner similar to that of GD3 ganglioside. Because ethanol is known to trigger mitochondria-mediated apoptosis with cytochrome c release and caspase 3 activation in the 7-day-old mouse brain, the GM2 elevation in mitochondria may be relevant to neuroapoptosis. Subsequently, activated microglia accumulated GM2, indicating a close relationship between GM2 and ethanol-induced neurodegeneration.

Preparation and electrophoretic separation of Bodipy-Fl-labeled glycosphingolipids

Several glycosphingolipids were labeled with the fluorphore Bodipy-Fl and analyzed using capillary electrophoresis with laser-induced fluorescence detection. GM1-, LacCer-, and Cer-Bodipy-Fl were prepared through acylation using the N-hydroxysuccinimide ester of Bodipy-Fl. Several other glycosphingolipids including GT1a-, GD1a-, GM2-, GM3-, GD3-, and GlcCer-Bodipy-Fl were enzymatically synthesized. Micellar electrokinetic capillary chromatography with a TRIS/CHES/SDS/α-cyclodextrin buffer produced better separation than an established borate/deoxycholate/methyl-β-cyclodextrin buffer. The nine Bodipy-Fl-labeled glycosphingolipid standards were separated in under 5 min, theoretical plate counts were between 640,000 and 740,000, and the limit of detection was approximately 3 pM or 240 ymol analyte injected onto the capillary.

Unique sphingomyelin patches are targets of a beta-cell-specific antibody

To devise successful imaging and therapeutic strategies, the identification of β-cell surface markers is one of the challenges in diabetes research that has to be resolved. We previously showed that IC2, a rat monoclonal IgM antibody, can be used for ex vivo determination of β-cell mass by imaging. Further progress toward the development of an antibody-based imaging agent was hampered by the lack of knowledge regarding the nature and composition of the IC2 antigen. Here, we show a series of systematic experiments involving classical lipid extraction and chromatography techniques combined with immunochemistry, which led to the identification of sphingomyelin as the target antigen assembled in the form of patches on the β-cell surface. Our findings were verified by modulating SM by enzymatic cleavage, downregulation, upregulation, and perturbation of membrane SM and observation of corresponding changes in IC2 binding. Cholesterol participates in stabilization of these patches, as its removal results in loss of IC2 binding. We believe that these findings have implications for identifying future ligands for the proposed antigen for imaging purposes as well as for potential therapy, as sphingomyelin has been shown to play a role in the apoptotic cascade in pancreatic β cells.

Lipid analysis by thin-layer chromatography--a review of the current state

High-performance thin-layer chromatography (HPTLC) is a widely used, fast and relatively inexpensive method of separating complex mixtures. It is particularly useful for smaller, apolar compounds and offers some advantages over HPLC. This review gives an overview about the special features as well as the problems that have to be considered upon the HPTLC analysis of lipids. The term "lipids" is used here in a broad sense and comprises fatty acids and their derivatives as well as substances related biosynthetically or functionally to these compounds. After a short introduction regarding the stationary phases and the methods how lipids can be visualized on an HPTLC plate, the individual lipid classes will be discussed and the most suitable solvent systems for their separation indicated. The focus will be on lipids that are most abundant in biological systems, i.e. cholesterol and its derivates, glycerides, sphingo- and glycolipids as well as phospholipids. Finally, a nowadays very important topic, the combination between HPTLC and mass spectrometric (MS) detection methods will be discussed. It will be shown that this is a very powerful method to investigate the identities of the HPTLC spots in more detail than by the use of common staining methods. Future aspects of HPTLC in the lipid field will be also discussed.

Multidimensional approaches in LC and MS for phospholipid bioanalysis

The advancement of both LC and MS has contributed significantly to phospholipid analysis. Two major trends of developments have emerged in the past decade: application of dedicated online (or offline) LC–MS techniques including 2D and sophisticated chromatographic separations, and the development of so-called shotgun lipidomics represented by multidimensional MS-based techniques. However, neither of these techniques have been shown to be a universal solution for the increasing demand on the comprehensive information of lipid metabolomics in lipidomics studies. This is partially due to the intrinsic complexity of naturally occurring phospholipids in practice. It is evident that either chromatography or MS has to go multidimensional in order to fulfil this goal. This review focuses on recent developments of multidimensional MS, LC–MS and chromatographic approaches for lipidomics analysis. The perspectives and retrospectives of chromatography and MS in these aspects will be reviewed and discussed.

Advances on the compositional analysis of glycosphingolipids combining thin-layer chromatography with mass spectrometry

Glycosphingolipids (GSLs), composed of a hydrophilic carbohydrate chain and a lipophilic ceramide anchor, play pivotal roles in countless biological processes, including infectious diseases and the development of cancer. Knowledge of the number and sequence of monosaccharides and their anomeric configuration and linkage type, which make up the principal items of the glyco code of biologically active carbohydrate chains, is essential for exploring the function of GSLs. As part of the investigation of the vertebrate glycome, GSL analysis is undergoing rapid expansion owing to the application of novel biochemical and biophysical technologies. Mass spectrometry (MS) takes part in the network of collaborations to further unravel structural and functional aspects within the fascinating world of GSLs with the ultimate aim to better define their role in human health and disease. However, a single-method analytical MS technique without supporting tools is limited yielding only partial structural information. Because of its superior resolving power, robustness, and easy handling, high-performance thin-layer chromatography (TLC) is widely used as an invaluable tool in GSL analysis. The intention of this review is to give an insight into current advances obtained by coupling supplementary techniques such as TLC and mass spectrometry. A retrospective view of the development of this concept and the recent improvements by merging (1) TLC separation of GSLs, (2) their detection with oligosaccharide-specific proteins, and (3) in situ MS analysis of protein-detected GSLs directly on the TLC plate, are provided. The procedure works on a nanogram scale and was successfully applied to the identification of cancer-associated GSLs in several types of human tumors. The combination of these two supplementary techniques opens new doors by delivering specific structural information of trace quantities of GSLs with only limited investment in sample preparation.

Imaging mass spectrometry of glycolipids

Mass spectrometry (MS) is an analytical technique that separates ionized molecules using differences in their mass, and can be used to determine the structure of the molecules. Matrix-assisted laser desorption/ionization (MALDI) is one of the most commonly used ionization methods for this procedure. A new technical method, imaging mass spectrometry (IMS), which is a two-dimensional MS, enables molecular imaging of tissue sections by the use of the MALDI-MS method. In this chapter, we briefly discuss available methods for analyzing glycolipids by IMS. We describe sample detection strategies, and also introduce a representative example of its research application.

Structural analysis of novel bioactive acylated steryl glucosides in pre-germinated brown rice bran

Previous studies from our laboratory indicated that pre-germinated brown rice (PR) contained certain unknown bioactive lipids that activated two enzymes related to diabetes: Na+/K+ATPase and homocysteine-thiolactonase. In this paper, we report on the isolation and structural characterization of the activator lipids from PR bran as acylated steryl glucosides (ASGs). The activator lipid was isolated by silica gel column chromatography, and its chemical structure was determined by NMR, GC-MS, and tandem mass spectrometry. We demonstrated that the bioactive component consists of a mixture of acylated steryl beta-glucosides. Delta8-cholesterol and 2-hydroxyl stearic acid were identified as constituents of ASGs. The steryl glucosides (SGs) subsequent to alkaline hydrolysis lost this enzyme activator activity. Soybean-derived ASGs were not active. This activity may be quite peculiar to PR-derived ASGs. Our findings suggest that the molecular species of ASG may play an important contributing role in the anti-diabetic properties of a PR diet.

High-sensitivity analysis of glycosphingolipids by matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight imaging mass spectrometry on transfer membranes

Glycosphingolipids are ubiquitous constituents of cells. Yet there is still room for improvement in the techniques for analyzing glycosphingolipids. Here we report our highly sensitive and convenient analytical technology with imaging mass spectrometry for detailed structural analysis of glycosphingolipids. We were able to determine detailed ceramide structures; i.e., both the sphingosine base and fatty acid, by MS/MS/MS analysis on a PVDF membrane with 10 pmol of GM1, with which only faint bands were visible by primuline staining. The limit of detection was approximately 1 pmol of GM1, which is lower than the value in the conventional reports (10 pmol).

Analysis of gangliosides directly from thin-layer chromatography plates by infrared matrix-assisted laser desorption/ionization orthogonal time-of-flight mass spectrometry with a glycerol matrix

A novel method is presented for direct coupling of high-performance thin-layer chromatography (HPTLC) with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the analysis of biomolecules. A first key feature is the use of a liquid matrix (glycerol), which provides a homogeneous wetting of the silica gel and a simple and fast MALDI preparation protocol. A second is the use of an Er:YAG infrared laser, which ablates layers of approximately 10-microm thickness of analyte-loaded silica gel and provides a soft desorption/ionization of even very labile analyte molecules. The orthogonal time-of-flight mass spectrometer employed in this study, finally provides a high accuracy of the mass determination, which is independent of any irregularity of the silica gel surface. The analytical potential of the method is demonstrated by the compositional mapping of a native GM3 (II(3)-alpha-Neu5Ac-LacCer) ganglioside mixture from cultured Chinese hamster ovary cells. The analysis is characterized by a high relative sensitivity, allowing the simultaneous detection of various major and minor GM3 species directly from individual HPTLC analyte bands. The lateral resolution of the direct HPTLC-MALDI-MS analysis is defined by the laser focus diameter of currently approximately 200 microm. This allows one to determine mobility profiles of individual species with a higher resolution than by reading off the chromatogram by optical absorption. The fluorescent dye primuline was, furthermore, successfully tested as a nondestructive, MALDI-compatible staining agent.

A cellular deficiency of gangliosides causes hypersensitivity to Clostridium perfringens phospholipase C

Clostridium perfringens phospholipase C (Cp-PLC), also called alpha-toxin, is the major virulence factor in the pathogenesis of gas gangrene. Previously, a cellular UDP-Glc deficiency was related with a hypersensitivity to the cytotoxic effect of Cp-PLC. Because UDP-Glc is required in the synthesis of proteoglycans, N-linked glycoproteins, and glycosphingolipids, the role of these gly-coconjugates in the cellular sensitivity to Cp-PLC was studied. The cellular sensitivity to Cp-PLC was significantly enhanced by glycosphingolipid synthesis inhibitors, and a mutant cell line deficient in gangliosides was found to be hypersensitive to Cp-PLC. Gangliosides protected hypersensitive cells from the cytotoxic effect of Cp-PLC and prevented its membrane-disrupting effect on artificial membranes. Removal of sialic acids by C. perfringens sialidase increases the sensitivity of cultured cells to Cp-PLC and intramuscular co-injection of C. perfringens sialidase, and Cp-PLC in mice potentiates the myotoxic effect of the latter. This work demonstrated that a reduction in gangliosides renders cells more susceptible to the membrane damage caused by Cp-PLC and revealed a previously unrecognized synergism between Cp-PLC and C. perfringens sialidase, providing new insights toward understanding the pathogenesis of clostridial myonecrosis.

Application of combined high-performance thin-layer chromatography immunostaining and nanoelectrospray ionization quadrupole time-of-flight tandem mass spectrometry to the structural characterization of high- and low-affinity binding ligands of Shiga toxin 1

Shiga toxin 1 (Stx1) represents an AB5 toxin produced by enterohemorrhagic Escherichia coli, which cause gastrointestinal diseases in humans that are often followed by potentially fatal systemic complications, such as acute encephalopathy and hemolytic uremic syndrome. The expression of the preferential Stx1 receptor, Gb3Cer/CD77 (Gal alpha1-4Gal beta1-4Glc beta1-1Cer), is one of the primary determinants of susceptibility to tissue injury. Due to the clinical importance of this life-threatening toxin, a combined strategy of preparative high-performance thin-layer chromatography (HPTLC) overlay assay and mass spectrometry was developed for the detection and structural characterization of Stx1-binding glycosphingolipids (GSLs). A preparation of neutral GSLs from human erythrocytes, comprising 21.4% and 59.1% of the high- and low-affinity Stx1-binding ligands Gb3Cer/CD77 and Gb4Cer, respectively, was separated on silica gel precoated HPTLC plates and probed for the presence of Stx1 receptors. Stx1 positive on the one hand and anti-Gb3Cer/CD77 and anti-Gb4Cer antibody positive bands from parallel reference runs on the other hand were extracted with chloroform/methanol/water (30/60/8, v/v/v). These crude extracts were used without any further purification for a detailed structural analysis by nanoelectrospray ionization quadrupole time-of-flight mass spectrometry (nanoESI-QTOF-MS) in the negative ion mode. In all extracts investigated, neutral GSLs were detected as singly charged deprotonated molecular ions, [M-H]-, and neither buffer-derived salt adducts nor coextracted contaminants from the overlay assay procedure or the silica gel layer were observed. For the structural characterization of Stx1- and antibody-binding GSLs low-energy collision-induced dissociation (CID) was applied to high and low abundant receptor species of the crude extracts. All MS/MS spectra obtained contained full series of Y-type ions, B-type ions and additional ions generated by ring cleavages of the sugar moiety. Only analytical quantities in the microgram scale of a single GSL species within the complex GSL mixture were required for the structural MS characterization of Stx1 ligands as Gb3Cer/CD77 and Gb4Cer. This effective combined HPTLC/MS procedure offers a broad range of applications, not only for toxins of bacterial origin, but also for any GSL-binding agents such as plant-derived lectins or human proteins with yet unknown binding specificities.

Oral uridine pro-drug PN401 decreases neurodegeneration, behavioral impairment, weight loss and mortality in the 3-nitropropionic acid mitochondrial toxin model of Huntington's disease

Huntington's disease (HD) is associated with decreased activity of mitochondrial succinate dehydrogenase (complex II). De novo biosynthesis of uridine nucleotides is directly coupled to the respiratory chain. Cells with impaired mitochondrial function become uridine auxotrophs and can be maintained with high micromolar concentration of uridine and pyruvate. The therapeutic role of pyrimidines and possible changes in uridine content has not been assessed in neurological diseases involving mitochondrial dysfunction in vivo. Oral administration of PN401 delivers much higher levels of uridine to the circulation than oral administration of uridine itself. Administration of complex II inhibitor 3-nitropropionic acid (3NP) induced neuronal damage in the striatum, substantia nigra and/or thalamus in 80% of the mice and led to 38% mortality. Treatment with PN401 almost completely prevented the neuronal damage due to 3NP and completely prevented mortality. In two subsequent experiments, 3NP-induced weight loss, mortality and behavioral impairment in rotarod performance and spontaneous motor activity were attenuated by treatment with oral PN401. 3NP did not reduce forebrain total uridine nucleotides (TUN), though higher doses of PN401 associated with optimal neuroprotection did elevate TUN to supranormal levels. Thus, oral PN401 treatment has neuroprotective effects in a HD model of mitochondrial dysfunction and the mechanism is more complex than correction of a pyrimidine deficit.

Gangliosides with O-acetylated sialic acids in tumors of neuroectodermal origin

Gangliosides, carrying an O-acetylated sialic acid in their carbohydrate moiety, are often found in growing and developing tissues, especially of neuro-ectodermal origin. The most prominent one is 9-O-Ac-GD3, which is considered as an oncofetal marker in animal and human tumors like neuronal tumors, melanoma, basalioma or breast cancer, as well as in psoriatic lesions. Also other gangliosides like GD2 or GT3 were found to be O-acetylated in their terminal sialic acid. In this review we are summarising the occurrence of such gangliosides in normal and transformed tissues and delineate a more general theory that O-acetylated sialic acids in gangliosides are a universal marker for growing cells and tissues.