Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 891
Filtrar
1.
Drug Des Devel Ther ; 13: 707-718, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30858700

RESUMO

Background: Local anesthetics in spinal anesthesia have neurotoxic effects, resulting in severe neurological complications. Intrathecal monosialoganglioside (GM1) administration has a therapeutic effect on bupivacaine-induced neurotoxicity. The aim of this study was to determine the underlying mechanisms of bupivacaine-induced neurotoxicity and the potential neuroprotective role of GM1. Materials and methods: A rat spinal cord neurotoxicity model was established by injecting bupivacaine (5%, 0.12 µL/g) intrathecally. The protective effect of GM1 (30 mg/kg) was evaluated by pretreating the animals with it prior to the bupivacaine regimen. The neurological and locomotor functions were assessed using standard tests. The histomorphological changes, neuron degeneration and apoptosis, and endoplasmic reticulum stress (ERS) relevant markers were analyzed using immunofluorescence, quantitative real-time PCR, and Western blotting. Results: Bupivacaine resulted in significant neurotoxicity in the form of aberrant neurolocomoter functions and spinal cord histomorphology and neuronal apoptosis. Furthermore, the ERS specific markers were significantly upregulated during bupivacaine-induced neurotoxicity. These neurotoxic effects were ameliorated by GM1. Conclusion: Pretreatment with GM1 protects against bupivacaine-induced neurotoxicity via the inhibition of the GRP78/PERK/eIF2α/ATF4-mediated ERS.


Assuntos
Bupivacaína/antagonistas & inibidores , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Gangliosídeos/farmacologia , Fármacos Neuroprotetores/farmacologia , Síndromes Neurotóxicas/tratamento farmacológico , Animais , Bupivacaína/toxicidade , Gangliosídeos/química , Masculino , Fármacos Neuroprotetores/química , Ratos , Ratos Sprague-Dawley
2.
Adv Carbohydr Chem Biochem ; 76: 113-148, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30851743

RESUMO

Gangliosides comprise a varied family of glycosphingolipid structures bearing one or more sialic acid residues. They are found in all mammalian tissues but are most abundant in the brain, where they represent the quantitatively major class of sialoglycans. As prominent molecular determinants on cell surfaces, they function as molecular-recognition partners for diverse glycan-binding proteins ranging from bacterial toxins to endogenous cell-cell adhesion molecules. Gangliosides also regulate the activity of plasma membrane proteins, including protein tyrosine kinases, by lateral association in the same membranes in which they reside. Their roles in molecular recognition and membrane protein regulation implicate gangliosides in human physiology and pathology, including infectious diseases, diabetes, cancer, and neurodegeneration. The varied structures and biosynthetic pathways of gangliosides are presented here, along with representative examples of their biological functions in health and disease.


Assuntos
Gangliosídeos/metabolismo , Receptores de Superfície Celular/metabolismo , Animais , Doença , Gangliosídeos/química , Gangliosídeos/genética , Saúde , Humanos , Receptores de Superfície Celular/química , Receptores de Superfície Celular/genética
4.
Glycoconj J ; 36(1): 79-90, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30612272

RESUMO

Mainly restricted to the nervous system in healthy adults, complex gangliosides such as GD3 and GD2 have been shown to be involved in aggressiveness and metastasis of neuro-ectoderm derived tumors such as melanoma and neuroblastoma. Interestingly, O-acetylated forms of GD2, not expressed in human peripheral nerve fibers, are highly expressed in GD2+ tumor cells. Very little information is known regarding the expression of O-acetylated disialogangliosides in breast cancer (BC) cell lines. Here, we analyzed the expression of GD2, GD3 and their O-acetylated forms O-acetyl-GD2 (OAcGD2) and O-acetyl-GD3 (OAcGD3) in BC cells. We used Hs 578T and SUM159PT cell lines, as well as cell clones over-expressing GD3 synthase derived from MDA-MB-231 and MCF-7. Using flow cytometry and immunocytochemistry/confocal microscopy, we report that BC cells express b-series gangliosides GD3 and GD2, as well as significant amounts of OAcGD2. However, OAcGD3 expression was not detected in these cells. O-acetylation of gangliosides isolated from BC cells was examined by LC-MS analysis of sialic acid DMB-derivatives. We report that the main acetylated form of sialic acid expressed in BC gangliosides is 9-O-acetyl-N-acetylneuraminic acid (Neu5,9Ac2). These results highlight a close interrelationship between Neu5,9Ac2 and OAcGD2 expression, and suggest that OAcGD2 is synthetized from GD2 and not from OAcGD3 in BC cells.


Assuntos
Neoplasias da Mama/metabolismo , Gangliosídeos/química , Ácidos Siálicos/análise , Feminino , Gangliosídeos/metabolismo , Humanos , Células MCF-7 , Ácidos Siálicos/química
5.
Chemistry ; 25(3): 796-805, 2019 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-30351481

RESUMO

The chemical synthesis of the highly branched core oligosaccharides of lipooligosaccharides (LOSs) found in Campylobacter jejuni, which causes Guillain-Barré syndrome by a preceding infection, is described. The target LOS mimics, consisting of eight or nine monosaccharides, were classified into three groups as key building blocks: ganglioside-core tetra-/pentasaccharides (GM1-/GD1a-like), l-glycero-d-manno-heptose-containing trisaccharides, and 3-deoxy-d-manno-2-octulosonic acid (KDO) residues. These synthetic fragments were obtained from commercially available monosaccharides. Less obtainable l-glycero-d-manno-heptose and KDO residues, as key components of the LOSs, were synthesized from p-methoxyphenyl d-mannoside and di-O-isopropylidene-protected d-mannose, respectively. The synthesis of α-KDO glycoside, as one of the most difficult stereocontrolled glycosidic constructions, was achieved by treating a 2,3-ene derivative of KDO with phenylselenyl trifluoromethanesulfonate as a suitable α-directing reagent. All synthetic blocks were constructed through a convergent synthetic route, which resulted in the first synthesis of structurally challenging LOS core glycans containing ganglioside GM1 and GD1a-core sequences.


Assuntos
Campylobacter jejuni/metabolismo , Lipopolissacarídeos/química , Oligossacarídeos/síntese química , Infecções por Campylobacter/complicações , Infecções por Campylobacter/patologia , Gangliosídeos/química , Glicosilação , Síndrome de Guillain-Barré/etiologia , Síndrome de Guillain-Barré/imunologia , Síndrome de Guillain-Barré/patologia , Humanos , Espectroscopia de Ressonância Magnética , Oligossacarídeos/química , Trissacarídeos/química
6.
Adv Exp Med Biol ; 1104: 41-58, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30484243

RESUMO

Ganglioside s are involved in a variety of physiological roles and particularly in the formation and function of lipid rafts in cell membranes. However, the dynamic behaviors of gangliosides have not been investigated in living cells owing to the lack of fluorescent probes that behave like their parental molecules. This has recently been resolved by developing new fluorescent ganglioside analogues that act similarly to their parental molecules, synthesized by only chemical methods. We performed single fluorescent-molecule imaging and revealed that ganglioside probes dynamically enter and exit rafts containing CD59, a glycosylphosphatidylinositol (GPI)-anchored protein, both before and after stimulation. The residency time of our ganglioside probes in CD59 oligomers was 48 ms after stimulation. The residency times in CD59 homodimer and monomer rafts were 40 and 12 ms, respectively. These results reveal the first direct evidence that GPI-anchored receptors and gangliosides interact in a cholesterol-dependent manner. Furthermore, they demonstrate that gangliosides continually move in and out of rafts that contain CD59 in an extremely dynamic manner and at a much higher frequency than expected. In this chapter, we review methods for the development and single-molecule imaging of new fluorescent ganglioside analogues and discuss how raft domains are formed, both before and after receptor engagement.


Assuntos
Antígenos CD59/química , Gangliosídeos/química , Glicosilfosfatidilinositóis/química , Microdomínios da Membrana/química , Humanos
7.
Analyst ; 143(21): 5234-5246, 2018 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-30272072

RESUMO

Clustered into the so-called "glycosynaptic" microdomains in the central nervous system (CNS), gangliosides (GGs) are involved in the formation of functional synapses and neural circuits. Therefore, GGs are important biomarkers in the early diagnosis of CNS pathologies, which are the focus of our research as potential therapeutic targets. A series of neuropsychiatric disorders, including Alzheimer's disease and schizophrenia, are characterized by amnesia and disorientation caused by hippocampal atrophy and diminished cholinergic activity. Based on ion mobility mass spectrometry (IM-MS) capability for the reliable determination of glycopatterns, the changes in the diversity and number of GGs with age and the occurrence of neurological disorders, we report here the development of a high performance IM-MS strategy for assessing the GG profile in a complex mixture extracted from a 20 year old hippocampus. IM separation of GGs based on the charge state, carbohydrate chain length and degree of sialylation led to the detection and identification of 140 species, the largest number of GGs ever reported in an adult hippocampus. Moreover, the obtained data support the concept of GG cholinergic activity. IM tandem MS experiments using collision induced dissociation (CID) confirmed the incidence of GD1b(d18:1/24:1) in the investigated hippocampus specimen.


Assuntos
Gangliosídeos/química , Hipocampo/química , Adulto , Gangliosídeos/isolamento & purificação , Humanos , Espectrometria de Massas/métodos , Estrutura Molecular , Adulto Jovem
8.
Anal Chem ; 90(22): 13193-13199, 2018 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-30335964

RESUMO

Sialic acids occur widely as glycoconjugates at the nonreducing ends of glycans. Glycosphingolipids (GSLs) include a large number of sialyl-linked glycan isomers with α2,3-, α2,6-, and α2,8-linked polysialic acids. Thus, it is difficult to distinguish structural isomers with the same mass by mass spectrometry. The sialic acid linkage specific alkylamidation (SALSA) method has been developed for discriminating between α2,3- and α2,6-linked isomers, but sequential amidation of linkage-specific sialic acids is generally complicated and time-consuming. Moreover, analysis of GSL-glycans containing α2,8-linked polysialic acids using solid-phase SALSA has not been reported. Herein, we report a novel SALSA method focused on ring-opening aminolysis (aminolysis-SALSA), which shortens the reaction time and simplifies the experimental procedures. We demonstrate that aminolysis-SALSA can successfully distinguish serum GSL-glycan isomers by mass spectrometry. In addition, ring-opening aminolysis can easily be applied to amine and hydrazine derivatives.


Assuntos
Gangliosídeos/sangue , Glicômica/métodos , Lactonas/química , Polissacarídeos/sangue , Ácidos Siálicos/química , Animais , Bovinos , Fenômenos Químicos , Gangliosídeos/química , Isomerismo , Polissacarídeos/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos
9.
J Phys Chem B ; 122(41): 9482-9489, 2018 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-30257562

RESUMO

This study focuses on the interaction of human amyloid ß-peptide (Aß) with a lipid-raft model membrane under macromolecular crowding conditions that mimic the intracellular environment. Aß is central to the development of Alzheimer's disease (AD) and has been studied extensively to determine the molecular mechanisms of Aß-induced cellular dysfunctions underlying the pathogenesis of AD. According to evidence from spectroscopic studies, ganglioside clusters are key to the fibrillization process of Aß. Gangliosides are a major component of glycosphingolipids and are acidic lipids of the central nervous system known to form so-called lipid rafts. In this study, the small unilamellar vesicle (SUV) membrane, composed of monosialogangliosides, cholesterol, and 1,2-dipalmitoyl- sn-glycero-3-phosphocholine, did not show any structural changes after the addition of Aß under noncrowding conditions. However, the addition of Aß under crowding conditions induced shape deformation and aggregation to SUV resulting in multilamellar stacking. The time evolution of the lamellar peak suggested the preferential cohesion or intercalation of the Aß peptide into the interbilayer region. This phenomenon was only observed at the gel (Lß) phase. These results suggest that an intracellular crowding environment promotes Aß-membrane interaction and a selective accumulation of Aß peptides into the interbilayer regions.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Bicamadas Lipídicas/metabolismo , Fragmentos de Peptídeos/metabolismo , Lipossomas Unilamelares/metabolismo , 1,2-Dipalmitoilfosfatidilcolina/química , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , Peptídeos beta-Amiloides/química , Colesterol/química , Colesterol/metabolismo , Gangliosídeos/química , Gangliosídeos/metabolismo , Humanos , Bicamadas Lipídicas/química , Microdomínios da Membrana , Fragmentos de Peptídeos/química , Ligação Proteica , Multimerização Proteica , Lipossomas Unilamelares/química
10.
FEBS Lett ; 592(23): 3992-4006, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30188569

RESUMO

The unveiling of ganglioside metabolism and biological function in the last decades depended on the extensive study of inherited human disease, studies with cultured cells, and specifically designed mouse models. Nonetheless, only few of the accomplishments made so far would have been possible without the use of labeled gangliosides, such as their radiolabeled and/or fluorescent analogs, as well as other modified gangliosides bearing cross-linking, affinity, or paramagnetic groups. Over the years, chemists and biochemists have made tremendous progress toward developing labeled gangliosides for their application in biological systems. These labeled ganglioside probes of the ganglio series have been successfully incorporated in cultured vertebrate cells and in artificial model membranes. In this Review, I provide an overview over the different methods, mostly semisynthetic procedures, to obtain these labeled ganglioside probes that have been used to elucidate the molecular basis of ganglioside-related biology as well as the physicochemical properties of gangliosides.


Assuntos
Corantes Fluorescentes/química , Gangliosídeos/biossíntese , Gangliosídeos/química , Marcação por Isótopo , Animais , Sequência de Carboidratos , Células Cultivadas , Humanos , Modelos Animais , Pesquisa/tendências
11.
Anal Bioanal Chem ; 410(25): 6585-6594, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30054694

RESUMO

Negative-ion hydrophilic liquid chromatography-electrospray ionization mass spectrometry (HILIC/ESI-MS) method has been optimized for the quantitative analysis of ganglioside (GM3) and other polar lipid classes, such as sulfohexosylceramides (SulfoHexCer), sulfodihexosylceramides (SulfoHex2Cer), phosphatidylglycerols (PG), phosphatidylinositols (PI), lysophosphatidylinositols (LPI), and phosphatidylserines (PS). The method is fully validated for the quantitation of the studied lipids in kidney normal and tumor tissues of renal cell carcinoma (RCC) patients based on the lipid class separation and the coelution of lipid class internal standard with the species from the same lipid class. The raw data are semi-automatically processed using our software LipidQuant and statistically evaluated using multivariate data analysis (MDA) methods, which allows the complete differentiation of both groups with 100% specificity and sensitivity. In total, 21 GM3, 28 SulfoHexCer, 26 SulfoHex2Cer, 10 PG, 19 PI, 4 LPI, and 7 PS are determined in the aqueous phase of lipidomic extracts from kidney tumor tissue samples and surrounding normal tissue samples of 20 RCC patients. S-plots allow the identification of most upregulated (PI 40:5, PI 40:4, GM3 34:1, and GM3 42:2) and most downregulated (PI 32:0, PI 34:0, PS 36:4, and LPI 16:0) lipids, which are primarily responsible for the differentiation of tumor and normal groups. Another confirmation of most dysregulated lipids is performed by the calculation of fold changes together with T and p values to highlight their statistical significance. The comparison of HILIC/ESI-MS data and matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) data confirms that lipid dysregulation patterns are similar for both methods. Graphical abstract ᅟ.


Assuntos
Carcinoma de Células Renais/química , Gangliosídeos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Padrões de Referência
12.
Methods Mol Biol ; 1804: 1-17, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926402

RESUMO

In this chapter, we briefly describe the structural features of gangliosides, and focus on the peculiar chemicophysical features of gangliosides, an important class of membrane amphipathic lipids that represent an important driving force determining the organization and properties of cellular membranes.


Assuntos
Fenômenos Químicos , Gangliosídeos/química , Conformação Molecular
13.
Methods Mol Biol ; 1804: 19-55, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926403

RESUMO

This review begins by attempting to recount some of the pioneering discoveries that first identified the presence of gangliosides in the nervous system, their structures and topography. This is presented as prelude to the current emphasis on physiological function, about which much has been learned but still remains to be elucidated. These areas include ganglioside roles in nervous system development including stem cell biology, membranes and organelles within neurons and glia, ion transport mechanisms, receptor modulation including neurotrophic factor receptors, and importantly the pathophysiological role of ganglioside aberrations in neurodegenerative disorders. This relates to their potential as therapeutic agents, especially in those conditions characterized by deficiency of one or more specific gangliosides. Finally we attempt to speculate on future directions ganglioside research is likely to take so as to capitalize on the impressive progress to date.


Assuntos
Gangliosídeos/química , Gangliosídeos/metabolismo , Sistema Nervoso/metabolismo , Animais , Humanos , Transporte de Íons , Modelos Biológicos , Sistema Nervoso/embriologia , Doenças Neurodegenerativas/metabolismo , Células-Tronco/metabolismo
14.
Methods Mol Biol ; 1804: 57-82, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926404

RESUMO

Scattering techniques are applied to studying the structural features of ganglioside aggregates in solution. Here it is described how different probing radiations allow to access different structural and dynamical parameters on different lengthscales. Besides a brief but comprehensive description of the scattering measurements, several practical suggestions are given concerning the experiments and the data analysis.


Assuntos
Gangliosídeos/química , Luz , Nêutrons , Espalhamento de Radiação , Micelas , Movimento (Física) , Raios X
15.
Methods Mol Biol ; 1804: 97-141, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926406

RESUMO

Gangliosides are sialic acid containing glycosphingolipids, which are abundant in mammalian brain tissue. Several fatal human diseases are caused by defects in glycolipid metabolism. Defects in their degradation lead to an accumulation of metabolites upstream of the defective reactions, whereas defects in their biosynthesis lead to diverse problems in a large number of organs.Gangliosides are primarily positioned with their ceramide anchor in the neuronal plasma membrane and the glycan head group exposed on the cell surface. Their biosynthesis starts in the endoplasmic reticulum with the formation of the ceramide anchor, followed by sequential glycosylation reactions, mainly at the luminal surface of Golgi and TGN membranes, a combinatorial process, which is catalyzed by often promiscuous membrane-bound glycosyltransferases.Thereafter, the gangliosides are transported to the plasma membrane by exocytotic membrane flow. After endocytosis, they are degraded within the endolysosomal compartments by a complex machinery of degrading enzymes, lipid-binding activator proteins, and negatively charged lipids.


Assuntos
Gangliosídeos/metabolismo , Doenças Genéticas Inatas/metabolismo , Animais , Membrana Celular/metabolismo , Endossomos/metabolismo , Gangliosídeos/biossíntese , Gangliosídeos/química , Humanos , Redes e Vias Metabólicas
16.
Methods Mol Biol ; 1804: 207-221, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926410

RESUMO

This chapter describes protocols for mass spectrometry (MS) applied to the characterization of ganglioside structures and the determination of ganglioside contents. Matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) are often used to ionize biological materials and this chapter covers three protocols for atmospheric pressure MALDI MS (AP-MALDI MS), liquid chromatography-ESI MS (LC-ESI MS), and LC-ESI MS with multiple reaction monitoring (MRM). Purified gangliosides were used in AP-MALDI MS analyses while crude preparations of gangliosides were subjected to LC-ESI MS and LC-ESI MS with MRM. The LC protocol includes conditions for both reversed-phase and normal-phase column chromatography.


Assuntos
Gangliosídeos/química , Espectrometria de Massas/métodos , Animais , Encéfalo/metabolismo , Bovinos , Cromatografia Líquida , Análise de Dados , Gangliosídeos/sangue , Humanos , Camundongos , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
17.
Methods Mol Biol ; 1804: 231-239, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926412

RESUMO

Because chemical fixatives like aldehydes do not work on most lipid molecules in the membrane, small-scale lipid distribution cannot be identified by immunoelectron microscopy in cells fixed by conventional methods. Here we describe a method for physically stabilizing membranes through quick-freezing and freeze-fracture replica formation and for specifically labeling gangliosides for electron microscopy. This method enables the ultrahigh-resolution mapping of membrane lipids including gangliosides within the two-dimensional plane of membranes.


Assuntos
Gangliosídeos/química , Microscopia Imunoeletrônica/métodos , Animais , Técnicas de Cultura de Células , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Fibroblastos/metabolismo , Técnica de Fratura por Congelamento , Congelamento , Camundongos , Coloração e Rotulagem
18.
Methods Mol Biol ; 1804: 241-284, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926413

RESUMO

Structure, conformation, and dynamics of sphingolipids can provide substantial help in better understanding sphingolipid-ligand interaction mechanisms. Both the oligosaccharide structure and the ceramide moiety of native glycosphingolipid can be established directly by NMR spectroscopic analysis without the necessity to resort to any other chemical or spectroscopic methods. NMR is a powerful technique to investigate interaction between small ligand, such as ganglioside, and membrane protein.


Assuntos
Gangliosídeos/análise , Espectroscopia de Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Gangliosídeos/química , Micelas , Conformação Molecular , Simulação de Dinâmica Molecular , Espectroscopia de Prótons por Ressonância Magnética
19.
Methods Mol Biol ; 1804: 293-310, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926415

RESUMO

Various methods for the chemical synthesis of gangliosides have been investigated to date and numerous natural gangliosides and their structural analogues have been synthesized during the past three decades. Key technologies in the synthesis of gangliosides include α-selective sialylation and introduction of the ceramide moiety into the oligosaccharide chain. This chapter introduces two major strategies for ganglioside synthesis-the most commonly used strategy and the recently developed glucosylceramide cassette approach. Synthetic procedures for selected reactions are also presented.


Assuntos
Química Orgânica/métodos , Gangliosídeos/síntese química , Animais , Galactose/metabolismo , Gangliosídeos/química , Glucosilceramidas/metabolismo , Mamíferos , Conformação Molecular , Ácido N-Acetilneuramínico/metabolismo
20.
Methods Mol Biol ; 1804: 311-322, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29926416

RESUMO

In this chapter, we present the preparation of gangliosides isotopically labelled with 3H or 14C. The methods do not present specific difficulties and can be used in any radiochemical laboratory. Some procedures can be applied to both gangliosides and neutral glycosphingolipids.


Assuntos
Gangliosídeos/metabolismo , Radioatividade , Acetilação , Radioisótopos de Carbono/metabolismo , Ceramidas/metabolismo , Ácidos Graxos/metabolismo , Gangliosídeos/química , Oligossacarídeos/metabolismo , Coloração e Rotulagem , Trítio/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA