RESUMO
Metachromatic leukodystrophy is a neurological lysosomal deposit disease that affects public health despite its low incidence in the population. Currently, few reports are available on pathophysiological events related to enzyme deficiencies and subsequent sulfatide accumulation. This research aims to examine the use of metformin as an alternative treatment to counteract these effects. This was evaluated in human Schwann cells (HSCs) transfected or non-transfected with CRISPR-Cas9, and later treated with sulfatides and metformin. This resulted in transfected HSCs showing a significant increase in cell reactive oxygen species (ROS) production when exposed to 100 µM sulfatides (p = 0.0007), compared to non-transfected HSCs. Sulfatides at concentrations of 10 to 100 µM affected mitochondrial bioenergetics in transfected HSCs. Moreover, these analyses showed that transfected cells showed a decrease in basal and maximal respiration rates after exposure to 100 µM sulfatide. However, maximal and normal mitochondrial respiratory capacity decreased in cells treated with both sulfatide and metformin. This study has provided valuable insights into bioenergetic and mitochondrial effects of sulfatides in HSCs for the first time. Treatment with metformin (500 µM) restored the metabolic activity of these cells and decreased ROS production.
Assuntos
Leucodistrofia Metacromática , Metformina , Sistemas CRISPR-Cas , Humanos , Leucodistrofia Metacromática/genética , Leucodistrofia Metacromática/metabolismo , Metformina/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Células de Schwann/metabolismo , Sulfoglicoesfingolipídeos/metabolismoRESUMO
Key measures to halt the spread of tuberculosis (TB) include early diagnosis, effective treatment, and monitoring disease management. We sought to evaluate the use of serum immunoglobulin levels against antigens present in cell envelope of Mycobacterium tuberculosis to monitor TB treatment response in children and adolescents with pulmonary (PTB) or extrapulmonary TB (EPTB). Blood samples were collected prior to and one, two, and six months following treatment initiation. Serum immunoglobulin levels against cardiolipin, sulfatide, mycolic acid and Mce1A protein were measured by ELISA. Serum from 53 TB patients and 12 healthy participants were analyzed. After six months of successful treatment, there was a significant decrease (p < 0.0001) in IgM levels against cardiolipin, sulfatide, mycolic acid and Mce1A protein and IgG levels against Mce1A protein when compared to baseline immunoglobulin levels. There was no significant variation in antibody levels during follow-up between participants with PTB and EPTB, confirmed and unconfirmed TB diagnosis, and HIV infection status. Antibody levels in control participants without TB did not decrease during follow-up. These results suggest that immunoglobulin responses to mycobacterial cell wall products may be a useful tool to monitor treatment response in children and adolescents with PTB or EPTB.
Assuntos
Antituberculosos/uso terapêutico , Monitoramento de Medicamentos , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose Pulmonar/tratamento farmacológico , Adolescente , Fatores Etários , Proteínas de Bactérias/imunologia , Biomarcadores/sangue , Cardiolipinas/imunologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Mycobacterium tuberculosis/imunologia , Ácidos Micólicos/imunologia , Valor Preditivo dos Testes , Estudos Prospectivos , Sulfoglicoesfingolipídeos/imunologia , Fatores de Tempo , Resultado do Tratamento , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/microbiologiaRESUMO
We compared the lateral structure of giant unilamellar vesicles (GUVs) composed of three pseudo binary mixtures of different glycosphingolipid (GSL), i.e. sulfatide, asialo-GM1 or GM1, with POPC. These sphingolipids possess similar hydrophobic residues but differ in the size and charge of their polar head group. Fluorescence microscopy experiments using LAURDAN and DiIC18 show coexistence of micron sized domains in a molar fraction range that depends on the nature of the GSLs. In all cases, experiments with LAURDAN show that the membrane lateral structure resembles the coexistence of solid ordered and liquid disordered phases. Notably, the overall extent of hydration measured by LAURDAN between the solid ordered and liquid disordered membrane regions show marked similarities and are independent of the size of the GSL polar head group. In addition, the maximum amount of GSL incorporated in the POPC bilayer exhibits a strong dependence on the size of the GSL polar head group following the order sulfatide>asialo-GM1>GM1. This observation is in full harmony with previous experiments and theoretical predictions for mixtures of these GSL with glycerophospholipids. Finally, compared with previous results reported in GUVs composed of mixtures of POPC with the sphingolipids cerebroside and ceramide, we observed distinctive curvature effects at particular molar fraction regimes in the different mixtures. This suggests a pronounced effect of these GSL on the spontaneous curvature of the bilayer. This observation may be relevant in a biological context, particularly in connection with the highly curved structures found in neural cells.
Assuntos
Gangliosídeo G(M1)/química , Bicamadas Lipídicas/química , Fosfatidilcolinas/química , Sulfoglicoesfingolipídeos/química , Lipossomas Unilamelares/química , 2-Naftilamina/análogos & derivados , 2-Naftilamina/química , Carbocianinas/química , Corantes Fluorescentes/química , Lauratos/química , Microscopia de Fluorescência , Estrutura MolecularRESUMO
Hypertension is a major traditional risk factor for atherosclerosis, and carotid artery intima-media thickness (IMT) is considered to be an important marker of atherosclerosis. Sulfatides have been shown to play a role in atherogenesis and vascular inflammation, resulting in atherosclerosis. This study aimed to assess the association between serum sulfatide and carotid artery IMT among hypertensive patients. We chose 60 hypertensive patients and 30 matched healthy controls. All subjects had medical examinations at Hebei General Hospital between March 2011 and March 2012. Measurements and other factors compared included serum sulfatide level, carotid artery IMT, and conventional cardiovascular risk factors. Hypertensive patients had higher BMIs (24.4 ± 7.6 to 23.1 ± 3.1 kg/m(2)), total cholesterol levels (5.5 ± 0.6 to 5.0 ± 1.1 mM), serum sulfatide levels (3.5 ± 3.9 to 8.3 ± 2.7 µM), and carotid artery IMTs (1.06 ± 0.15 to 0.79 ± 0.07 mm) (all P < 0.05) than control patients. Furthermore, the serum sulfatide level positively correlated with carotid IMT in the hypertensive patients (r = 0.39, P = 0.002). Multiple linear regression analysis showed serum sulfatide was an independent risk factor affecting IMT (P = 0.04). These results suggest that serum sulfatide is more strongly associated with carotid artery IMT than other traditional risk factors in hypertensive patients.
Assuntos
Biomarcadores/sangue , Doenças das Artérias Carótidas/sangue , Hipertensão/sangue , Sulfoglicoesfingolipídeos/sangue , Idoso , Aterosclerose/patologia , Artérias Carótidas/metabolismo , Artérias Carótidas/patologia , Doenças das Artérias Carótidas/patologia , Espessura Intima-Media Carotídea , Feminino , Humanos , Hipertensão/patologia , Masculino , Pessoa de Meia-Idade , Fatores de RiscoRESUMO
PURPOSE: To assess if arylsulfatase A activity (ASA) and sulfatide (SL) concentration in the human endometrium can be predictive of the development of endometrial polyps over the years, since ASA activity reflects the endometrial sensitivity to hormones. METHODS: ASA activity and SL concentration were determined by biochemical procedures on endometrial samples collected between 1990 and 1994 in non-menopausal women. These women underwent a new endometrial sampling following the clinical indication some years after the first endometrial sampling. The histological assessment of the second endometrial specimens found four patients with normal endometrial pattern and 10 patients with one or more endometrial polyps. ASA activity/years elapsed and SL concentration/years elapsed were compared using two tailed Mann-Whitney test for unpaired data between patients with normal pattern and patients with endometrial polyps. RESULTS: Median ASA activities were 2.62 (normal pattern) versus 1.85 (endometrial polyps) nmol hydrolized substrate/min. Median activity/years elapsed is higher in patients with second endometrial sample presenting normal pattern (p=0.006) and median SL concentration/years elapsed does not differ significantly among groups, even if median SL concentration seems to be higher in patients who subsequently developed polyps (1031 µg/g of fresh tissue versus 341,5 µg/g of fresh tissue). CONCLUSIONS: ASA activity can predict the onset of endometrial polyps over the years.
Assuntos
Cerebrosídeo Sulfatase/metabolismo , Pólipos/enzimologia , Doenças Uterinas/enzimologia , Adulto , Endométrio/química , Feminino , Humanos , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Sulfoglicoesfingolipídeos/análise , Fatores de TempoRESUMO
PURPOSE: To assess if arylsulfatase A activity (ASA) and sulfatide (SL) concentration in the human endometrium can be predictive of the development of endometrial polyps over the years, since ASA activity reflects the endometrial sensitivity to hormones. METHODS: ASA activity and SL concentration were determined by biochemical procedures on endometrial samples collected between 1990 and 1994 in non-menopausal women. These women underwent a new endometrial sampling following the clinical indication some years after the first endometrial sampling. The histological assessment of the second endometrial specimens found four patients with normal endometrial pattern and 10 patients with one or more endometrial polyps. ASA activity/years elapsed and SL concentration/years elapsed were compared using two tailed Mann-Whitney test for unpaired data between patients with normal pattern and patients with endometrial polyps. RESULTS: Median ASA activities were 2.62 (normal pattern) versus 1.85 (endometrial polyps) nmol hydrolized substrate/min. Median activity/years elapsed is higher in patients with second endometrial sample presenting normal pattern (p=0.006) and median SL concentration/years elapsed does not differ significantly among groups, even if median SL concentration seems to be higher in patients who subsequently developed polyps (1031 µg/g of fresh tissue versus 341,5 µg/g of fresh tissue). CONCLUSIONS: ASA activity can predict the onset of endometrial polyps over the years.
OBJETIVO: Avaliar se a atividade da arilsulfatase A (ASA) e a concentração de sulfatida (SL) no endométrio humano pode ser preditivo em relação ao desenvolvimento de pólipos endometriais ao longo dos anos, posto que atividade da ASA reflete a sensibilidade do endométrio aos hormônios. MÉTODOS: A atividade da ASA, assim como a concentração de SL, foi determinada por meio de procedimentos bioquímicos em amostras de endométrio coletadas entre 1990 e 1994, em mulheres que não se encontravam na menopausa. Essas mulheres foram submetidas a uma nova amostragem endometrial após indicação clínica alguns anos depois da primeira amostragem endometrial. A avaliação histológica dos segundos espécimes endometriais permitiu identificar quatro pacientes com padrão endometrial normal e 10 com um ou mais pólipos endometriais. A atividade da ASA/anos depois e a concentração de SL/anos depois foram comparadas, utilizando o teste bilateral U de Mann-Whitney para dados não pareados entre as pacientes com padrão normal e as pacientes com pólipos endometriais. RESULTADOS: A ativitade da ASA foi 2,62 (padrão normal) em comparação com 1,85 (endometrial pólipos) de substrato hidrolisado/min. A atividade da ASA/anos depois é maior em pacientes com segunda amostra endometrial a apresentarem um padrão normal (p=0,006), e a concentração mediana de SL/anos depois não difere de forma significativa entre os grupos, apesar de a concentração mediana de SL parecer maior em pacientes que posteriormente desenvolveram pólipos (1031 µg/g de tecido fresco em comparação com 341,5 µg/g de tecido fresco). CONCLUSÕES: A atividade da ASA pode prever a aparição de pólipos endometriais ao longo dos anos.
Assuntos
Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Cerebrosídeo Sulfatase/metabolismo , Pólipos/enzimologia , Doenças Uterinas/enzimologia , Endométrio/química , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Sulfoglicoesfingolipídeos/análise , Fatores de TempoRESUMO
Sulphoglycosphingolipids, present on the surface of diverse cells, participate in the regulation of various cellular events. However, little is known about the structure and the role of sulphoglycosphingolipids in trypanosomatids. Herein, sulphated dihexosylceramide structures - composed mainly of sphingosine as the long chain base acylated with stearic acid - have been determined for the first time in Trypanosoma cruzi epimastigotes by UV-MALDI-TOF-MS analysis. Interestingly, inhibition ELISA assays using cruzipain as antigen and polyclonal rabbit antibodies specific for cruzipain, the major cysteine proteinase of T. cruzi, or for its C-terminal domain, have demonstrated (i) that sulphate epitopes are shared between cruzipain and sulphatides of T. cruzi, (ii) that cross-reactivity maps to the C-terminal domain and (iii) the existence of other antigenic determinants in the glycolipidic structures. These features provide evidence that sulphate groups are antigenic in sulphate-containing parasite glycoconjugates. Furthermore, IgG2 antibody levels inversely correlate with disease severity in chronic Chagas disease patients, suggesting that IgG2 antibodies specific for sulphated epitopes might be associated with protective immunity and might be considered as potential surrogates of the course of chronic Chagas disease.
Assuntos
Glicoconjugados/análise , Glicoconjugados/imunologia , Sulfoglicoesfingolipídeos/análise , Sulfoglicoesfingolipídeos/imunologia , Trypanosoma cruzi/química , Trypanosoma cruzi/imunologia , Adulto , Animais , Antiprotozoários/sangue , Doença de Chagas/imunologia , Reações Cruzadas , Cisteína Endopeptidases/química , Cisteína Endopeptidases/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Proteínas de Protozoários , Coelhos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Metachromatic leukodystrophy (MLD) is a lysosomal disorder caused by arylsulfatase A (ARSA) deficiency. It is classified into three forms according to the age of onset of symptoms (late infantile, juvenile, and adult). We carried out a cross-sectional and retrospective study, which aimed to determine the epidemiological, clinical, and biochemical profile of MLD patients from a national reference center for Inborn Errors of Metabolism in Brazil. Twenty-nine patients (male, 17) agreed to participate in the study (late infantile form: 22; juvenile form: 4; adult form: 1; asymptomatic: 2). Mean ages at onset of symptoms and at biochemical diagnosis were, respectively, 19 and 39 months for late infantile form and 84.7 and 161.2 months for juvenile form. The most frequently reported first clinical symptom/sign of the disease was gait disturbance and other motor abnormalities (72.7%) for late infantile form and behavioral and cognitive alterations (50%) for juvenile form. Leukocyte ARSA activity level did not present significant correlation with the age of onset of symptoms (r = -0.09, p = 0.67). Occipital white matter and basal nuclei abnormalities were not found in patients with the late infantile MLD. Our results suggest that there is a considerable delay between the age of onset of signs and symptoms and the diagnosis of MLD in Brazil. Correlation between ARSA activity and MLD clinical form was not found. Further studies on the epidemiology and natural history of this disease with larger samples are needed, especially now when specific treatments should be available in the near future.
Assuntos
Cerebrosídeo Sulfatase/deficiência , Leucócitos/enzimologia , Leucodistrofia Metacromática/diagnóstico , Adolescente , Idade de Início , Biomarcadores/sangue , Biomarcadores/urina , Brasil/epidemiologia , Cerebrosídeo Sulfatase/sangue , Criança , Pré-Escolar , Estudos Transversais , Técnicas de Diagnóstico Oftalmológico , Progressão da Doença , Eletroencefalografia , Oftalmopatias/diagnóstico , Oftalmopatias/enzimologia , Oftalmopatias/epidemiologia , Feminino , Transtornos Neurológicos da Marcha/diagnóstico , Transtornos Neurológicos da Marcha/enzimologia , Transtornos Neurológicos da Marcha/epidemiologia , Humanos , Lactente , Leucodistrofia Metacromática/tratamento farmacológico , Leucodistrofia Metacromática/enzimologia , Leucodistrofia Metacromática/epidemiologia , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/enzimologia , Leucoencefalopatias/epidemiologia , Imageamento por Ressonância Magnética , Masculino , Transtornos Mentais/diagnóstico , Transtornos Mentais/enzimologia , Transtornos Mentais/epidemiologia , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Sulfoglicoesfingolipídeos/urina , Fatores de Tempo , Adulto JovemRESUMO
Sulfated glycosphingolipids are present on the surface of a variety of cells. They are active participants in adhesion processes in many systems and appear to be involved in the regulation of cell proliferation, differentiation and other developmental cellular events. However, the body of knowledge about synthesis, structure, and function of glycolipids in parasitic protozoa is very limited so far. In this work, we show by metabolic incorporation of [(14)C]palmitic acid, [(14)C]glucose and Na(2)(35)SO(4) that sulfoglycosphingolipids are biosynthesized in the three intraerythrocytic stages of Plasmodium falciparum. After saponification, purification of the labelled acidic components was achieved and two components named SPf1 and SPf2 were characterized. Chemical degradations and TLC analysis pointed out to sulfolipidic structures. Analysis by UV-MALDI-TOF mass spectrometry in the negative ion mode using nor-harmane as matrix showed for SPf2 a structure consisting in a disulfated hexose linked to a 20:1 sphingosine acylated with C18:0 fatty acid. Interestingly, parasite treatment with low concentrations of d,l-threo-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP) caused an arrest on parasite development associated to the inhibition of sulfoglycolipid biosynthesis. Taking into account that sulfoglycolipidic structures are currently involved in adhesion processes, our findings open the possibility to study the participation of this type of structures in the described aggregation phenomena in severe malaria and may contribute to clarify the pathogenesis of the disease. This report shows for the first time the synthesis of sulfoglycolipids in Apicomplexa.
Assuntos
Plasmodium falciparum/metabolismo , Sulfoglicoesfingolipídeos/metabolismo , Animais , Antimaláricos/farmacologia , Radioisótopos de Carbono/metabolismo , Cromatografia em Camada Fina , Glucose/metabolismo , Espectrometria de Massas , Morfolinas/farmacologia , Ácido Palmítico/metabolismo , Plasmodium falciparum/química , Plasmodium falciparum/efeitos dos fármacos , Esfingolipídeos/farmacologia , Sulfatos/metabolismo , Sulfoglicoesfingolipídeos/análiseRESUMO
EhABP-120 is the first filamin identified in the parasitic protozoan Entamoeba histolytica. Filamins are a family of cross-linking actin-binding proteins that promote a dynamic orthogonal web. They have been reported to interact directly with more than 30 cellular proteins and some phosphoinositides. The biochemical consequences of these interactions may have either positive or negative effects on the cross-linking function and also form a link between the cytoskeleton and plasma membrane. In this study, the EhABP-120 carboxy-terminal domain (END) was biochemically characterized. This domain was able to associate to 3-sulfate galactosyl ceramide, a new lipid target for a member of the filamin family. Also, the END domain was able to dimerize "in vitro." Molecular modeling analysis showed that the dimeric region is stabilized by a disulfide bond. Electrostatic and docking studies suggest that an electropositive concave pocket at the dimeric END domain interacts simultaneously with several sulfogalactose moieties of the sulfatide.
Assuntos
Proteínas Contráteis/química , Proteínas Contráteis/metabolismo , Entamoeba histolytica/metabolismo , Proteínas dos Microfilamentos/química , Proteínas dos Microfilamentos/metabolismo , Sulfoglicoesfingolipídeos/metabolismo , Sequência de Aminoácidos , Animais , Membrana Celular/química , Membrana Celular/genética , Membrana Celular/metabolismo , Proteínas Contráteis/genética , Entamoeba histolytica/genética , Filaminas , Proteínas dos Microfilamentos/genética , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Alinhamento de Sequência , Especificidade por Substrato , TransfecçãoRESUMO
We demonstrated that administration of interferon gamma (IFN-gamma) to pregnant rats conferred partial resistance in their offspring to further challenge with Trypanosoma cruzi. Because of the effects of IFN-gamma on macrophage activation and immunoglobulin isotype selection, offspring were now studied to ascertain whether this intervention modifies the in vitro replication of T. cruzi and nitric oxide (NO) production by peritoneal macrophages (PE), together with the anti-T. cruzi IgG isotypes. To evaluate the possibility of a detrimental effect of IFN-gamma, serum levels of anti-sulphatide autoantibodies were also investigated. Offspring were born to mothers undergoing one of the following procedures during gestation: treatment with recombinant rat IFN-gamma, 50,000 IU/rat, five times/week for 3 weeks, which was started on the day of mating; infection with 10(6) trypomastigotes of T. cruzi at 7, 14, and 21 days after mating plus IFN-gamma treatment as given to the former group; the same protocol except that physiological saline was injected instead of IFN-gamma; injection of physiological saline only. Offspring were challenged at weaning with a similar dose of T. cruzi, to constitute four groups of infected young, plus an additional group of age-matched uninfected rats born to control mothers. PE were harvested at day 7 postinfection (pi), exposed to parasites and further investigated for the replication of T. cruzi and NO production, whereas ELISA studies for measuring serum anti-T. cruzi IgG subclasses and anti-sulphatide autoantibodies were performed at day 30 pi. The number of intracellular parasites in PE was markedly decreased in young born to IFN-gamma-treated mothers, this not being accompanied by higher nitrite levels in culture supernatants. Offspring delivered by IFN-gamma-treated mothers showed no higher serum concentrations of anti-sulphatide autoantibodies, but exhibited a preferential synthesis of anti-T. cruzi IgG2b antibodies. This rat isotype is known to fix complement and constitutes the rat counterpart of IgG2a mouse immunoglobulins whose synthesis is favoured by IFN-gamma.
Assuntos
Anticorpos Antiprotozoários/biossíntese , Doença de Chagas/imunologia , Imunoglobulina G/biossíntese , Interferon gama/farmacologia , Macrófagos/parasitologia , Complicações Parasitárias na Gravidez/imunologia , Trypanosoma cruzi/imunologia , Animais , Feminino , Imunoglobulina G/classificação , Óxido Nítrico/biossíntese , Gravidez , Ratos , Proteínas Recombinantes , Sulfoglicoesfingolipídeos/imunologia , Trypanosoma cruzi/crescimento & desenvolvimento , Aumento de PesoRESUMO
Earlier studies in Trypanosoma cruzi-infected rats revealed an increased antibody activity against sulfatide, a specific constituent of both myelin sheaths of peripheral nerves and T. cruzi epimastigotes. To investigate further the characteristics of such anti-sulfatide antibodies, we analyzed their IgG isotypes as well as their ability to bind to homologous neural host structures. Antisulfatide IgG-enriched fractions were obtained from rats acutely infected with T. cruzi. Immunoglobulin isotypes were determined by an enzyme-linked immunosorbent assay (ELISA) method to show that IgG2a and, more significantly, IgG2b were the predominant isotypes of antisulfatide autoantibodies. Further immunofluorescence studies carried out in coronal sections of the rat forebrain revealed, in turn, that antisulfatide antibodies were capable of reacting with homologous neural tissues. Specific binding of these rat autoantibodies to sulfocerebroside on cell surfaces in vivo may in theory play some detrimental role, given the reported ability of rat IgG2b to fix complement or to mediate antibody-dependent cell-mediated cytotoxicity reactions.
Assuntos
Autoanticorpos/sangue , Doença de Chagas/imunologia , Prosencéfalo/imunologia , Sulfoglicoesfingolipídeos/imunologia , Doença Aguda , Animais , Especificidade de Anticorpos , Doença Crônica , Corpo Caloso/imunologia , Feminino , Imunoglobulina G/sangue , Isotipos de Imunoglobulinas/sangue , Masculino , Ratos , Ratos EndogâmicosRESUMO
Phospholipase A2 activity against mixed monolayers of dilauroylphosphatidic acid or dilauroylphosphatidylcholine with glycosphingolipids can be reversibly modulated by external constant electrostatic fields. The changes of enzymatic activity are correlated to the depolarization or hyperpolarization of the film caused by specific dipolar properties of glycosphingolipids. Hyperpolarizing fields enhance the enzymatic activity against pure dilauroylphosphatidic acid while depolarizing fields induce a decrease of activity. Compared to the pure substrate, the interface of mixed films containing neutral glycosphingolipids or gangliosides is already partially depolarized and the magnitude of activation induced by an external hyperpolarizing field is decreased; conversely, depolarizing fields cause an increased inhibition of activity. Differing from gangliosides, sulfatides bring about a hyperpolarization of the mixed lipid monolayer and external hyperpolarizing or depolarizing fields cause enhanced activation and reduced inhibition, respectively. The effects of glycosphingolipids depend on their relative proportion in the monolayer. Results were similar with dilauroylphosphosphatidylcholine but the field effects were less than half of those found with dilauroylphosphatidic acid. Our work shows that the activity of phospholipase A2 in addition to responding reversibly to external electrostatic fields, is directly modulated by the polarity and magnitude of the lipid polar head group dipole moments.
Assuntos
Glicoesfingolipídeos/metabolismo , Fosfolipases A/metabolismo , Animais , Bovinos , Gangliosídeos/química , Gangliosídeos/metabolismo , Glicoesfingolipídeos/química , Técnicas In Vitro , Potenciais da Membrana , Modelos Moleculares , Conformação Molecular , Ácidos Fosfatídicos/química , Ácidos Fosfatídicos/metabolismo , Fosfolipases A2 , Eletricidade Estática , Sulfoglicoesfingolipídeos/química , Sulfoglicoesfingolipídeos/metabolismo , SuínosAssuntos
Anticorpos/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Hanseníase Tuberculoide/diagnóstico , Hanseníase Tuberculoide/imunologia , Hanseníase Virchowiana/diagnóstico , Hanseníase Virchowiana/imunologia , Hanseníase/classificação , Hanseníase/diagnóstico , Hanseníase/imunologia , Imunoglobulina G , Imunoglobulina M , SulfoglicoesfingolipídeosRESUMO
We have characterized the fluorescence properties of 6-dodecanoyl-2-dimethylamine-naphthalene (LAURDAN) in pure interfaces formed by sphingomyelin and 10 chemically related glycosphingolipids (GSLs).1 The GSLs contain neutral and anionic carbohydrate residues in their oligosaccharide chain. These systems were studied at temperatures below, at, or above the main phase transition temperature of the pure lipid aggregates. The extent of solvent dipolar relaxation around the excited fluorescence probe in the GSLs series increases with the magnitude of the glycosphingolipid polar headgroup below the transition temperature. This conclusion is based on LAURDAN's excitation generalized polarization (GPex) and fluorescence lifetime values found in the different interfaces. A linear dependence between the LAURDAN GPex and the intermolecular spacing among the lipid molecules was found for both neutral and anionic lipids in the GSLs series. This relationship was also followed by phospholipids. We conclude that LAURDAN in these lipid aggregates resides in sites containing different amounts of water. The dimension of these sites increases with the size of the GSLs polar headgroup. The GP function reports on the concentration and dynamics of water molecules in these sites. Upon addition of cholesterol to Gg4Cer, the fluorescence behavior of LAURDAN was similar to that of pure cerebrosides and sphingomyelin vesicles. This observation was attributed to a change in the interfacial hydration as well as changes in the shape and size of the Gg4Cer aggregates in the presence of cholesterol. After the addition of cholesterol to gangliosides, the changes in the LAURDAN's spectral parameters decrease progressively as the polar headgroup of these lipids becomes more complex. This finding suggests that the dehydration effect of cholesterol depends strongly on the curvature radius and the extent of hydration of these lipid aggregates. In the gel phase of phrenosine, GalCer, Gg3Cer, sulfatide, and sphingomyelin, the excitation red band (410 nm) of LAURDAN was reduced with respect to that of LAURDAN in the gel phase of pure phospholipids. This observation indicates a local environment that interacts differently with the ground state of LAURDAN in GSLs when compared with LAURDAN in phospholipids.
Assuntos
2-Naftilamina/análogos & derivados , Corantes Fluorescentes , Glicoesfingolipídeos/química , Lauratos , Sítios de Ligação , Fenômenos Biofísicos , Biofísica , Sequência de Carboidratos , Colesterol/química , Gangliosídeos/química , Técnicas In Vitro , Modelos Moleculares , Dados de Sequência Molecular , Fosfolipídeos/química , Espectrometria de Fluorescência , Esfingomielinas/química , Sulfoglicoesfingolipídeos/química , Termodinâmica , Água/químicaRESUMO
A specific treatment for Chagas' disease has not yet been discovered, even though the condition is endemic in large parts of the Region of the Americas. Earlier studies have addressed the possibility that the sulfatide galactocerebroside in Trypanosoma cruzi behaves as an immunogen involved in the production of the high antisulfatide antibody levels found in patients with chronic infestation with the parasite. This may be an important factor in the pathogenesis of the cardiac symptoms and peripheral neuropathy seen in Chagas' disease, which is the most important cause of myocarditis in Central and South America and the second most important cause of heart failure in several of the countries located in these subregions. The present study was conducted in order to ascertain whether patients with Chagas' disease and other patients not afflicted with the ailment differ insofar as the presence of antibodies against sulfatide is concerned, and it describes antisulfatide antibody levels in 124 hospital patients (74 men and 50 women) between the ages of 15 and 94 who were in the cardiology unit of Vargas Hospital in Caracas from 1 July to 30 June 1995. Antisulfatide antibody titers were determined by means of enzyme-linked immunosorbent assays (ELISA), and the antigen employed was sulfatide cerebroside obtained from bovine brain tissue. Of the 124 patients under study, 39 (31.5%) suffered from Chagas' disease and had antisulfatide antibody levels higher than those detected in patients without Chagas (P = 0.0298) and in 28 seemingly healthy controls (P = 0.0035). Serum levels of antisulfatide antibodies in patients with other forms of heart disease were also compared with those seen in the control group, and significantly higher levels were found in patients with acute ischemic heart disease (P = 0.0049), rheumatic valvular heart disease (P = 0.0075), chronic ischemic heart disease (P = 0.0464) and bradiarrythmias (P = 0.0157), and significantly lower ones in subjects with hypertensive heart disease (P = 0.0367). These antibody levels showed no correlation with clinical or paraclinical variables indicative of the degree of cardiac compromise. Our results support the notion that antibodies against sulfatide may play a role in the pathogenesis of Chagas' cardiomyopathy and other forms of heart disease and should be further studied in an effort to determine their potential role in these processes.
Assuntos
Anticorpos Antiprotozoários/imunologia , Cardiomiopatia Chagásica/imunologia , Animais , Bovinos , Cardiomiopatia Chagásica/microbiologia , Doença Crônica , Feminino , Cardiopatias/epidemiologia , Cardiopatias/imunologia , Humanos , Masculino , Sulfoglicoesfingolipídeos/imunologia , Trypanosoma cruzi/imunologiaRESUMO
Earlier work indicated that Trypanosoma cruzi infection in pregnant rats decreased the amount of myocardial damage that developed in their chronically infected offspring. Given the suspected role of autoimmune mechanisms in the generation of chronic myocarditis, we evaluated whether this maternal intervention was likely to affect the synthesis of autoantibodies in infected young. Autoantibodies were investigated against molecules exhibiting cross-reactivity with T. cruzi antigens or not, that is cerebroside sulphate (sulphatide) and actin, respectively. Female '1' rats (75 days old) that had been mated with syngeneic sires were separated into two groups, one challenged with living trypomastigotes at 7, 14 and 21 days following mating, and the other one given physiologic saline at the same intervals. At the time of weaning, offspring were injected with 10(6)/T. cruzi to constitute two infected groups: young born to infected mothers (InMoTc) and young delivered by uninfected mothers (CoMoTc). Serum antibodies were investigated by ELISA at 30 and 60 days post-infection, which represents acute and chronic infection, respectively. T. cruzi infection was associated with the production of anti-sulphatide antibodies, but the phenomenon was significantly less evident in InMoTc young and virtually unnoticeable during their chronic infection. Unlike the anti-sulphatide results, levels of anti-actin antibodies showed no differences between CoMoTc and InMoTc rats when compared during acute or chronic infection. The decreased production of anti-sulphatide autoantibodies of InMoTc offspring may be due to a modification of the immune repertoire of offspring because of the contact with parasite antigens during ontogeny.
Assuntos
Autoanticorpos/biossíntese , Doença de Chagas/complicações , Doença de Chagas/imunologia , Troca Materno-Fetal/imunologia , Complicações Parasitárias na Gravidez/imunologia , Actinas/imunologia , Animais , Antígenos de Protozoários , Cardiomiopatia Chagásica/etiologia , Cardiomiopatia Chagásica/imunologia , Feminino , Masculino , Gravidez , Ratos , Sulfoglicoesfingolipídeos/imunologia , Trypanosoma cruzi/imunologiaRESUMO
The molecular organization, interactions, phase state and membrane-membrane interactions of model membranes containing cerebroside (GalCer), sulfatide (Sulf) and myelin basic protein (MBP) were investigated. Sulf shows a larger cross-sectional area than GalCer, in keeping with the lateral electrostatic repulsions in the negatively charged polar head group. The interactions of GalCer with different phospholipids are similar while those with Sulf depend on the phosphoryl choline moiety in the phospholipid. MBP induces a decrease of the phase transition temperature in both lipids but with Sulf this occurs at lower proportions of MBP. In mixtures of Sulf with phosphatidylcholine MBP induces phase separation among Sulf-rich and PC-rich domains. Extensive apposition of bilayers containing Sulf is induced by MBP while GalCer interferes with this process. Few membrane interactions proceed to bilayer merging or whole bilayer fusion and the glycosphingolipids help preserve the membrane integrity.
Assuntos
Glicoesfingolipídeos/química , Membranas Artificiais , Proteína Básica da Mielina/química , Bainha de Mielina/química , Animais , Química Encefálica , Bovinos , Cerebrosídeos/química , Fenômenos Químicos , Físico-Química , Galactosilceramidas/química , Bicamadas Lipídicas/química , Proteína Básica da Mielina/farmacologia , Sulfoglicoesfingolipídeos/químicaRESUMO
Se trata de la primera parte de 2 artículos tendientes a aclarar el valor de exámenes serológicos en el diagnóstico de las neuropatías autoinmunes. Específicamente de los anticuerpos antineurales y de las gamapatías monoclonales. En esta primera revisión se presentan las posibilidades y limitaciones de los anticuerpos antineurales en manejo clínico de estas neuropatías. En primer lugar se describen las características generales de los distintos tipos de anticuerpos. Los síndromes polineuropáticos han sido divididos en motores, sensitivos, sensitivo/motores y Guillain-Barré, discutiéndose para cada caso la utilidad diagnóstica de los distintos anticuerpos antineurales
Assuntos
Autoanticorpos , Doenças Autoimunes/imunologia , Neuropatias Hereditárias Sensoriais e Autônomas/imunologia , Autoanticorpos/classificação , Doenças Autoimunes/diagnóstico , Doenças Desmielinizantes/diagnóstico , Gangliosídeos/imunologia , Glicoproteína Associada a Mielina/imunologia , Neuropatias Hereditárias Sensoriais e Autônomas/diagnóstico , Polirradiculoneuropatia/imunologia , Testes Sorológicos , Sulfoglicoesfingolipídeos/imunologiaRESUMO
The P3 murine monoclonal antibody (MAb) was generated by immunizing BALB/c mice with NeuGcGM3 included into liposomes. The specificity of this MAb was defined by an enzyme-linked immunosorbent assay and immunostaining on thin-layer chromatograms. P3 MAb binds to NeuGc-containing gangliosides and was shown also to react with sulfated glycolipids. A preliminary immunohistochemical study showed that the P3 MAb was able to recognize antigens expressed in human breast tumors.