Gangliosides GD1b Research Articles

Mice lacking sialyltransferase ST3Gal-II develop late-onset obesity and insulin resistance.

Sialyltransferases are a family of 20 gene products in mice and humans that transfer sialic acid from its activated precursor, CMP-sialic acid, to the terminus of glycoprotein and glycolipid acceptors. ST3Gal-II (coded by the St3gal2 gene) transfers sialic acid preferentially to the three positions of galactose on the Galβ1-3GalNAc terminus of gangliosides GM1 and GD1b to synthesize GD1a and GT1b, respectively. Mice with a targeted disruption of St3gal2 unexpectedly displayed late-onset obesity and insulin resistance. At 3 months of age, St3gal2-null mice were the same weight as their wild type (WT) counterparts, but by 13 months on standard chow they were visibly obese, 22% heavier and with 37% greater fat/lean ratio than WT mice. St3gal2-null mice became hyperglycemic and displayed impaired glucose tolerance by 9 months of age. They had sharply reduced insulin responsiveness despite equivalent pancreatic islet morphology. Analyses of insulin receptor (IR) tyrosine kinase substrate IRS-1 and downstream target Akt revealed decreased insulin-induced phosphorylation in adipose tissue but not liver or skeletal muscle of St3gal2-null mice. Thin-layer chromatography and mass spectrometry revealed altered ganglioside profiles in the adipose tissue of St3gal2-null mice compared to WT littermates. Metabolically, St3gal2-null mice display a reduced respiratory exchange ratio compared to WT mice, indicating a preference for lipid oxidation as an energy source. Despite their altered metabolism, St3gal2-null mice were hyperactive. We conclude that altered ganglioside expression in adipose tissue results in diminished IR sensitivity and late-onset obesity.

Detecting Protein-Glycolipid Interactions Using Glycomicelles and CaR-ESI-MS.

This study reports on the use of the catch-and-release electrospray ionization mass spectrometry (CaR-ESI-MS) assay, combined with glycomicelles, as a method for detecting specific interactions between water-soluble proteins and glycolipids (GLs) in aqueous solution. The B subunit homopentamers of cholera toxin (CTB5) and Shiga toxin type 1 B (Stx1B5) and the gangliosides GM1, GM2, GM3, GD1a, GD1b, GT1b, and GD2 served as model systems for this study. The CTB5 exhibits broad specificity for gangliosides and binds to GM1, GM2, GM3, GD1a, GD1b, and GT1b; Stx1B5 does not recognize gangliosides. The CaR-ESI-MS assay was used to analyze solutions of CTB5 or Stx1B5 and individual gangliosides (GM1, GM2, GM3, GD1a, GD1b, GT1b, and GD2) or mixtures thereof. The high affinity interaction of CTB5 with GM1 was successfully detected. However, the apparent affinity, as determined from the mass spectra, is significantly lower than that of the corresponding pentasaccharide or when GM1 is presented in model membranes such as nanodiscs. Interactions between CTB5 and the low affinity gangliosides GD1a, GD1b, and GT1b, as well as GD2, which served as a negative control, were detected; no binding of CTB5 to GM2 or GM3 was observed. The CaR-ESI-MS results obtained for Stx1B5 reveal that nonspecific protein-ganglioside binding can occur during the ESI process, although the extent of binding varies between gangliosides. Consequently, interactions detected for CTB5 with GD1a, GD1b, and GT1b are likely nonspecific in origin. Taken together, these results reveal that the CaR-ESI-MS/glycomicelle approach for detecting protein-GL interactions is prone to false positives and false negatives and must be used with caution. Graphical Abstract <!-- [INSERT GRAPHICAL ABSTRACT TEXT HERE] -->.

Exogenous and Endogeneous Disialosyl Ganglioside GD1b Induces Apoptosis of MCF-7 Human Breast Cancer Cells.

Gangliosides have been known to play a role in the regulation of apoptosis in cancer cells. This study has employed disialyl-ganglioside GD1b to apoptosis in human breast cancer MCF-7 cells using exogenous treatment of the cells with GD1b and endogenous expression of GD1b in MCF-7 cells. First, apoptosis in MCF-7 cells was observed after treatment of GD1b. Treatment of MCF-7 cells with GD1b reduced cell growth rates in a dose and time dependent manner during GD1b treatment, as determined by XTT assay. Among the various gangliosides, GD1b specifically induced apoptosis of the MCF-7 cells. Flow cytometry and immunofluorescence assays showed that GD1b specifically induces apoptosis in the MCF-7 cells with Annexin V binding for apoptotic actions in early stage and propidium iodide (PI) staining the nucleus of the MCF-7 cells. Treatment of MCF-7 cells with GD1b activated apoptotic molecules such as processed forms of caspase-8, -7 and PARP (Poly(ADP-ribose) polymerase), without any change in the expression of mitochondria-mediated apoptosis molecules such as Bax and Bcl-2. Second, to investigate the effect of endogenously produced GD1b on the regulation of cell function, UDP-gal: β1,3-galactosyltransferase-2 (GD1b synthase, Gal-T2) gene has been transfected into the MCF-7 cells. Using the GD1b synthase-transfectants, apoptosis-related signal proteins linked to phenotype changes were examined. Similar to the exogenous GD1b treatment, the cell growth of the GD1b synthase gene-transfectants was significantly suppressed compared with the vector-transfectant cell lines and transfection activated the apoptotic molecules such as processed forms of caspase-8, -7 and PARP, but not the levels of expression of Bax and Bcl-2. GD1b-induced apoptosis was blocked by caspase inhibitor, Z-VAD. Therefore, taken together, it was concluded that GD1b could play an important role in the regulation of breast cancer apoptosis.

A profile of sphingolipids and related compounds tentatively identified in yak milk

This work characterized a fraction of constituents in yak milk within the realm of approximately 1,000 to 3,000 Da using matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry. Eleven samples of yak milk powder from the Sichuan province of China were received by the Department of Food Science, University of Wisconsin–Madison, and stored at room temperature until analysis. Sample preparation involved delipidation and deproteinization of yak milk samples and cold ethanol precipitation. Subsequently, MALDI time-of-flight mass spectrometry was performed in positive ion, reflector mode (AB Sciex TOF/TOF 4800 MALDI; AB Sciex, Foster City, CA). The instrument was first calibrated with the manufacturer’s 6-peptide mixture, and each spectrum was internally calibrated using the accurate mass of ACTH Fragment 18–39 standard peptide (protonated mass at m/z 2464.199) present in each sample. Laser power was adjusted for the calibration standards and for each sample so that the signal obtained for the most-abundant ion in each spectrum could be maximized, or kept below ~2×104 to preserve spectral quality. Structure and name based on mass were matched using the Metlin metabolite database (https://metlin.scripps.edu/index.php). Results of the current work for yak milk powder showed a large variety of sphingolipid structures with clusters around 1,200, 1,600, and 2,000 Da. The profiling matched several glycosphingolipids, such as gangliosides GA1, GD1a, GD1b, GD3, GM1, GM2, GM3, and GT2 and several other unique moieties, including deaminated neuraminic acid (KDN) oligosaccharides, and fucose containing gangliosides. Matrix preparation and MALDI time-of-flight parameters were important factors established in this work to allow high resolution profiling of complex sphingolipids in yak powder milk.

Guillain-Barre syndrome

Guillain-Barre syndrome is an acute inflammatory demyelinating polyradiculoneuropathy of autoimmune etiology, which is characterized by peripheral paralysis and protein-cell dissociation in the cerebrospinal fluid in most cases. The Guillain-Barre syndrome prevalence is 0.6-2.4 cases per 100 thousand population. In Moscow, about 200 people are taken ill with Guillain-Barre syndrome each year. Currently, four main clinical variants of Guillain-Barre syndrome are described: acute inflammatory demyelinating polyradiculoneuropathy, axonal form, acute motor axonal neuropathy, and Miller-Fisher syndrome. Disease development is preceded by contact with the viral or bacterial infections causative agent such as Campylobacter jejuni, Mycoplasma pneumonia, cytomegalovirus, Epstein-Barr virus and influenza virus. Guillain-Barre syndrome pathogenesis is «molecular mimicry» between infectious agents surfaces and the peripheral nerves structures. High titer of antibodies to the GM1, GD1a, GD1b and GQ1b gangliosides is found in patients blood serum. Diagnostic criteria for the Guillain-Barre syndrome diagnosis are the physical examination results, cerebrospinal fluid analysis and electroneuromyographic study. The North American motor deficit severity scale is used to assess the neurological status. This scale allows to evaluate the patient’s condition and movement abilities. Currently plasmapheresis and immunoglobulin G therapy are the main treatment options for patients with Guillain-Barre syndrome. The favorable prognosis in the form of disease clinical manifestations regression reaches 60-80%. Mortality in Guillain-Barre syndrome is 5% in average and may reach 20% in patients on mechanical ventilation. The most common death causes of patients with Guillain-Barre syndrome are respiratory failure, aspiration pneumonia, sepsis, and pulmonary embolism. Early treatment initiation can reduce serious complications risk, including respiratory failure, what ultimately leads to decrease in mortality and patients disablement.

Intraventricular Sialidase Administration Enhances GM1 Ganglioside Expression and Is Partially Neuroprotective in a Mouse Model of Parkinson's Disease.

BackgroundPreclinical and clinical studies have previously shown that systemic administration of GM1 ganglioside has neuroprotective and neurorestorative properties in Parkinson’s disease (PD) models and in PD patients. However, the clinical development of GM1 for PD has been hampered by its animal origin (GM1 used in previous studies was extracted from bovine brains), limited bioavailability, and limited blood brain barrier penetrance following systemic administration.ObjectiveTo assess an alternative therapeutic approach to systemic administration of brain-derived GM1 to enhance GM1 levels in the brain via enzymatic conversion of polysialogangliosides into GM1 and to assess the neuroprotective potential of this approach.MethodsWe used sialidase from Vibrio cholerae (VCS) to convert GD1a, GD1b and GT1b gangliosides to GM1. VCS was infused by osmotic minipump into the dorsal third ventricle in mice over a 4-week period. After the first week of infusion, animals received MPTP injections (20 mg/kg, s.c., twice daily, 4 hours apart, for 5 consecutive days) and were euthanized 2 weeks after the last injection.ResultsVCS infusion resulted in the expected change in ganglioside expression with a significant increase in GM1 levels. VCS-treated animals showed significant sparing of striatal dopamine (DA) levels and substantia nigra DA neurons following MPTP administration, with the extent of sparing of DA neurons similar to that achieved with systemic GM1 administration.ConclusionThe results suggest that enzymatic conversion of polysialogangliosides to GM1 may be a viable treatment strategy for increasing GM1 levels in the brain and exerting a neuroprotective effect on the damaged nigrostriatal DA system.

Unilateral hypoglossal nerve palsy with asymmetric facial and limb paresis in axonal Guillain–Barré syndrome

AbstractWe report a 45‐year‐old man with motor axonal Guillain–Barré syndrome who developed left facial nerve palsy, right hypoglossal nerve palsy, and predominantly left‐sided upper limb paresis and left lower limb paresis. Blood examination identified immunoglobulin G antibodies against gangliosides GD1a, GD1b and GQ1b, and GD1b/GD1a and GD1b/GT1b complexes. He was treated with intravenous immunoglobulin (400 mg/kg/day for 5 days) twice, and tongue deviation and facial palsy resolved in 3 months. Unilateral or asymmetric involvement of the cranial and limb nerves represent a variant form of axonal Guillain–Barré syndrome.

CRISPR/Cas9-Mediated Genomic Deletion of the Beta-1, 4 N-acetylgalactosaminyltransferase 1 Gene in Murine P19 Embryonal Carcinoma Cells Results in Low Sensitivity to Botulinum Neurotoxin Type C.

Botulinum neurotoxins produced by Clostridium botulinum cause flaccid paralysis by inhibiting neurotransmitter release at peripheral nerve terminals. Previously, we found that neurons derived from the murine P19 embryonal carcinoma cell line exhibited high sensitivity to botulinum neurotoxin type C. In order to prove the utility of P19 cells for the study of the intracellular mechanism of botulinum neurotoxins, ganglioside-knockout neurons were generated by deletion of the gene encoding beta-1,4 N-acetylgalactosaminyltransferase 1 in P19 cells using the clustered regularly interspaced short palindromic repeats combined with Cas9 (CRISPR/Cas9) system. By using this system, knockout cells could be generated more easily than with previous methods. The sensitivity of the generated beta-1,4 N-acetylgalactosaminyltransferase 1-depleted P19 neurons to botulinum neurotoxin type C was decreased considerably, and the exogenous addition of the gangliosides GD1a, GD1b, and GT1b restored the susceptibility of P19 cells to botulinum neurotoxin type C. In particular, addition of a mixture of these three ganglioside more effectively recovered the sensitivity of knockout cells compared to independent addition of GD1a, GD1b, or GT1b. Consequently, the genome-edited P19 cells generated by the CRISPR/Cas9 system were useful for identifying and defining the intracellular molecules involved in the toxic action of botulinum neurotoxins.

Neuromyelitis optica phenotype associated with therapy-responsive acute peripheral neuropathy.

A 51-year-old Hispanic woman with a history of Churg-Strauss syndrome (in remission for 20 years)–associated mesangial glomerulonephritis and end-stage renal disease with a recent renal transplant and previously cured cytomegalovirus (CMV) infection who was on a tapering dose of tacrolimus presented with sudden onset of lower extremity numbness. Symptoms progressed to complete paraplegia and sensory loss over 24 hours. The following day, ascending paresis extended to bilateral upper extremities, with high thoracic sensory level and complete blindness. Initial MRI revealed contrast enhancement of bilateral prechiasmatic optic nerve as well as T2 hyperintensities involving the central gray matter of the entire spinal cord with associated edema. CSF analysis documented neutrophilic pleocytosis (182 neutrophils per mm3) and increased total protein level (142 mg/dL) without oligoclonal banding. Bacterial, fungal, and mycobacterial cultures from the CSF were negative, as was PCR for CMV, Epstein-Barr virus, herpes simplex virus, human herpesvirus 6, and varicella-zoster virus. Serologic autoimmune assessment, including onconeuronal, anti-neutrophil cytoplasmic antibody, and other rheumatologic, Lyme, and aquaporin-4 (AQP4) antibody testing, was negative. Moreover, testing for sarcoidosis and HIV antibody was unrevealing. Nerve conduction studies (NCS) performed 2 weeks after symptom onset documented severe reduction in compound motor action potential amplitudes (worse in the lower extremities), <10% slowing of distal latencies but not conduction velocities, and mildly slowed upper extremity f-wave latencies. Sensory nerve action potentials were pathologically reduced in the lower extremities (table). Needle examination (EMG) showed active, severe denervation changes in lower extremity muscles and less severe changes in upper extremity muscles. Subsequent GM1, GM2, GD1a, GD1b, and GQ1b ganglioside antibody testing was negative. The patient was diagnosed with concurrent clinically definite neuromyelitis optica (NMO) phenotype1 and acute axonal polyradiculoneuropathy with primarily axonal features.

Cell clustering and delay/arrest in T-cell division implicate a novel mechanism of immune modulation by E. coli heat-labile enterotoxin B-subunits

The B-subunits of heat-labile enterotoxins LT-I (LT-IB) and LT-IIa (LT-IIaB) are strong adjuvants that bind to cell-surface receptors, including gangliosides GM1 and GD1b, respectively. LT-IIaB also binds TLR-2. We demonstrate for the first time that co-incubation with the B-subunits induces significant clustering of B cells after only 4h, and B and T cells in 24h. Clustering was dependent on intact B-subunits, but not on the TLR-2 binding activity of LT-IIaB, indicating it was ganglioside-mediated. Treatment of B cells with LT-IB, a mixture of LT-IB+LT-IIaB, but not LT-IIaB alone, caused a delay in T cell division following ovalbumin endocytosis. B cell receptor-mediated uptake in presence of each treatment caused an arrest, but with increased production of IL-2. Further, treatments differentially increased the proportion of macrophages expressing MHC class-II. These results highlight the outcomes of interplay between signals involving different receptors and implicate a novel mechanism of adjuvanticity.

High Levels of Anti-Ganglioside Antibodies in Patients with Parkinson?s Disease Associated with Cognitive Decline

Background: Increasing evidence suggests that gangliosides act as important mediators in both demyelination and remyelination. Objective: The purpose of the present study was to investigate the presence of IgM antibodies against GM1, GD1b and GQ1b gangliosides in the sera of in patients who suffered from Parkinson’s disease in correlation with the clinical parameters. Method: The present research is based on the investigation of 44 patients (63.7-73.3 years) for anti-ganglioside antibodies and 44 healthy age- matched individuals, as normal controls, using Enzyme-Linked Immuno-Sorbent Assays. Results: The patients revealed increased levels of the tested antibodies, compared to normal controls (p=0.0005). A correlation between IgM anti-GM1 and the level of cognitive impairment (Minimental State Examination, p=0.003; Unified Parkinson’s Disease Rating Scale I, p=0.013) was also noticed. Conclusion: A peripheral neuroimmune response may occur in patients who suffer from Parkinson’s disease especially those with cognitive impairment. Further investigation is needed to establish a direct connection between that immune response and disease pathophysiology.

The probable auto-antigenic role of lipids (anti-ganglioside antibodies) in the pathogenesis of Alzheimer's disease.

We examined the sera of 103 demented patients of a mean age of 75 years and 60 age-matched healthy individuals, using ELISA, to investigate the levels of IgM antibodies against GM1, GD1b, and GQ1b gangliosides and their possible correlation with clinical parameters (age, severity, and type of dementia). All the individuals that demonstrated positive titers of anti-ganglioside antibodies were demented patients whereas normal controls showed borderline or negative values. Significant correlation was revealed between IgM anti-GM1 and both the age of the patients and the severity of dementia. Most of the patients with increased IgM anti-GD1b titers suffered from AD.

GD1b-specific antibodies may bind to complex of GQ1b and GM1, causing ataxia.

Monospecific IgG antibodies to GD1b ganglioside (GD1b-specific antibodies) have been found in patients with acute ataxic neuropathy and Guillain-Barré syndrome, but the association of the GD1b-specific antibodies with specific neurological conditions has yet to be established. We tested sera from more than 10,000 patients with various neurological disorders, and found six sera, which contained IgG antibodies to GD1b, but not to LM1, GM1, GM1b, GD1a, GalNAc-GD1a, GT1a, GT1b and GQ1b. All six patients who carried GD1b-specific antibodies presented with acute onset of ataxia and monophasic course of the illness, of whom five demonstrated cerebellar-like ataxia. Four patients had antecedent symptoms of upper respiratory tract infection. The six patients demonstrated areflexia, and four complained of distal numbness. All the six patients who had the GD1b-specific antibodies carried IgG antibodies to complex of GQ1b/GM1 and GT1a/GM1. GD1b-specific antibodies were significantly absorbed by GQ1b/GM1 and GT1a/GM1 and anti-GQ1b/GM1 and -GT1a/GM1 antibodies were absorbed by GD1b. In conclusion, the GD1b-specific antibodies, which recognizes GQ1b/GM1 or GT1a/GM1 complex, are associated with acute ataxia.

Antibodies against gangliosides in patients with dementia.

Increasing evidence suggests that gangliosides act as important mediators in both de- and remyelination. The scope of the present research was to investigate the presence of immunoglobulin (Ig) M antibodies against GM1, GD1b, and GQ1b gangliosides in the sera of patients with dementia and the possible connection with clinical parameters of the disease. This research topic demonstrates the investigation of 103 patients with dementia and 60 healthy individuals using enzyme-linked immunosorbent assay for the presence of 3 antiganglioside antibodies in their sera. The authors report a positive connection between IgM anti-GM1 and the age (P = .005) and the severity of dementia (P = .005). Most of the patients who revealed increased IgM anti-GD1b levels had Alzheimer's disease (AD; P = .002). This study indicates that elevated IgM anti-GM1 may be connected with the neurodegeneration in older patients with severe dementia and that AD may also be associated with increased IgM anti-GD1b levels.

A Structure-Guided Mutation in the Major Capsid Protein Retargets BK Polyomavirus

Viruses within a family often vary in their cellular tropism and pathogenicity. In many cases, these variations are due to viruses switching their specificity from one cell surface receptor to another. The structural requirements that underlie such receptor switching are not well understood especially for carbohydrate-binding viruses, as methods capable of structure-specificity studies are only relatively recently being developed for carbohydrates. We have characterized the receptor specificity, structure and infectivity of the human polyomavirus BKPyV, the causative agent of polyomavirus-associated nephropathy, and uncover a molecular switch for binding different carbohydrate receptors. We show that the b-series gangliosides GD3, GD2, GD1b and GT1b all can serve as receptors for BKPyV. The crystal structure of the BKPyV capsid protein VP1 in complex with GD3 reveals contacts with two sialic acid moieties in the receptor, providing a basis for the observed specificity. Comparison with the structure of simian virus 40 (SV40) VP1 bound to ganglioside GM1 identifies the amino acid at position 68 as a determinant of specificity. Mutation of this residue from lysine in BKPyV to serine in SV40 switches the receptor specificity of BKPyV from GD3 to GM1 both in vitro and in cell culture. Our findings highlight the plasticity of viral receptor binding sites and form a template to retarget viruses to different receptors and cell types.

Differential Distribution of Major Brain Gangliosides in the Adult Mouse Central Nervous System

Gangliosides - sialic acid-bearing glycolipids - are major cell surface determinants on neurons and axons. The same four closely related structures, GM1, GD1a, GD1b and GT1b, comprise the majority of total brain gangliosides in mammals and birds. Gangliosides regulate the activities of proteins in the membranes in which they reside, and also act as cell-cell recognition receptors. Understanding the functions of major brain gangliosides requires knowledge of their tissue distribution, which has been accomplished in the past using biochemical and immunohistochemical methods. Armed with new knowledge about the stability and accessibility of gangliosides in tissues and new IgG-class specific monoclonal antibodies, we investigated the detailed tissue distribution of gangliosides in the adult mouse brain. Gangliosides GD1b and GT1b are widely expressed in gray and white matter. In contrast, GM1 is predominately found in white matter and GD1a is specifically expressed in certain brain nuclei/tracts. These findings are considered in relationship to the hypothesis that gangliosides GD1a and GT1b act as receptors for an important axon-myelin recognition protein, myelin-associated glycoprotein (MAG). Mediating axon-myelin interactions is but one potential function of the major brain gangliosides, and more detailed knowledge of their distribution may help direct future functional studies.

A Rare Form of Guillan Barre Syndrome: A Child Diagnosed with Anti-GD1a and Anti-GD1b Positive Pharyngeal-Cervical-Brachial Variant.

Pharyngeal-cervical-brachial (PCB) variant is a rare form of Guillan-Barre Syndrome (GBS). Antibodies against other membrane proteins like GM1b and GD1a have been found only in a small number of patients with Guillan Barre syndrome variant. Here, we report a 5.5 year-old boy diagnosed early with positive GD1a and GD1b gangliosides of Guillan-Barre syndrome pharyngeal cervical-Brachial variant, who improved and recovered fully in a short period. This is in contrast to those whose recovery period prolongs in spite of early diagnosis and appropriate treatment and/or those who experience incomplete recovery. In summary, diagnosis of PCB variant of GBS should be considered in infants with sudden onset bulbar symptoms and muscle weakness, and it should be kept in mind that early diagnosis and appropriate treatment can give successful outcomes.

Antibodies Against Gangliosides in the Serum of Patients Suffering from Multiple Sclerosis Compared with Healthy Individuals

We examined the sera of 56 patients with definite multiple sclerosis (MS) and 44 healthy individuals using ELISA, for investigating the probable correlation between IgM antibodies against GM1, GD1b and GQ1b gangliosides and clinical parameters of MS. Patients revealed pathological concentrations of the examined antibodies, while healthy controls demonstrated normal levels (p=0.0005). A probable correlation between anti-GD1b and anti-GM1 IgM levels with the progression of MS and a positive comparison between the duration and the disability have also been indicated. Further investigation should be established in order to provide insights on the potential autoantigenic role of gangliosides in MS.

Immunohistochemical localization of the GM1, GD1a, GD1b and GQ1b gangliosides in the neuronal endings of rat muscle spindles

Immunohistochemical localization of the GM1, GD1a, GD1b and GQ1b gangliosides in the neuronal endings of rat muscle spindles

Specific synthesis of neurostatin and gangliosides O-acetylated in the outer sialic acids using a sialate transferase.

Gangliosides are sialic acid containing glycosphingolipids, commonly found on the outer leaflet of the plasma membrane. O-acetylation of sialic acid hydroxyl groups is one of the most common modifications in gangliosides. Studies on the biological activity of O-acetylated gangliosides have been limited by their scarcity in nature. This comparatively small change in ganglioside structure causes major changes in their physiological properties. When the ganglioside GD1b was O-acetylated in the outer sialic acid, it became the potent inhibitor of astroblast and astrocytoma proliferation called Neurostatin. Although various chemical and enzymatic methods to O-acetylate commercial gangliosides have been described, O-acetylation was nonspecific and produced many side-products that reduced the yield. An enzyme with O-acetyltransferase activity (SOAT) has been previously cloned from the bacteria Campylobacter jejuni. This enzyme catalyzed the acetylation of oligosaccharide-bound sialic acid, with high specificity for terminal alpha-2,8-linked residues. Using this enzyme and commercial gangliosides as starting material, we have specifically O-acetylated the gangliosides’ outer sialic acids, to produce the corresponding gangliosides specifically O-acetylated in the sialic acid bound in alpha-2,3 and alpha-2,8 residues. We demonstrate here that O-acetylation occurred specifically in the C-9 position of the sialic acid. In summary, we present a new method of specific O-acetylation of ganglioside sialic acids that permits the large scale preparation of these modified glycosphingolipids, facilitating both, the study of their mechanism of antitumoral action and their use as therapeutic drugs for treating glioblastoma multiform (GBM) patients.