RESUMO
Introduction: Recent evidence shows that oxidative stress seems to be related with the pathophysiology of X-linked adrenoleukodystrophy (X-ALD), a neurodegenerative disorder. Methods: In the present study, the in vitro effect of N-acetyl-L-cysteine (NAC) on glutathione (GSH) and sulfhydryl levels in X-ALD patients was evaluated. Results: A significant reduction of GSH and sulfhydryl content was observed in X-ALD patients compared to the control group. Furthermore, 5 mM of NAC, in vitro, led to an increase in GSH content and sulfhydryl groups in these patients. Conclusion: These data probably indicate that an adjuvant therapy with the antioxidant NAC could improve the oxidative imbalance in X-ALD patients(AU)
Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Acetilcisteína/farmacologia , Adrenoleucodistrofia/fisiopatologia , Glutationa/deficiência , Compostos de Sulfidrila/metabolismo , Adrenoleucodistrofia/tratamento farmacológico , Oxirredução/efeitos dos fármacos , Estresse OxidativoRESUMO
Plasmodium parasites are exposed to endogenous and exogenous oxidative stress during their complex life cycle. To minimize oxidative damage, the parasites use glutathione (GSH) and thioredoxin (Trx) as primary antioxidants. We previously showed that disruption of the Plasmodium berghei gamma-glutamylcysteine synthetase (pbggcs-ko) or the glutathione reductase (pbgr-ko) genes resulted in a significant reduction of GSH in intraerythrocytic stages, and a defect in growth in the pbggcs-ko parasites. In this report, time course experiments of parasite intraerythrocytic development and morphological studies showed a growth delay during the ring to schizont progression. Morphological analysis shows a significant reduction in size (diameter) of trophozoites and schizonts with increased number of cytoplasmic vacuoles in the pbggcs-ko parasites in comparison to the wild type (WT). Furthermore, the pbggcs-ko mutants exhibited an impaired response to oxidative stress and increased levels of nuclear DNA (nDNA) damage. Reduced GSH levels did not result in mitochondrial DNA (mtDNA) damage or protein carbonylations in neither pbggcs-ko nor pbgr-ko parasites. In addition, the pbggcs-ko mutant parasites showed an increase in mRNA expression of genes involved in oxidative stress detoxification and DNA synthesis, suggesting a potential compensatory mechanism to allow for parasite proliferation. These results reveal that low GSH levels affect parasite development through the impairment of oxidative stress reduction systems and damage to the nDNA. Our studies provide new insights into the role of the GSH antioxidant system in the intraerythrocytic development of Plasmodium parasites, with potential translation into novel pharmacological interventions.
Assuntos
Glutamato-Cisteína Ligase/genética , Glutationa Redutase/genética , Glutationa/metabolismo , Malária/parasitologia , Plasmodium berghei/genética , Animais , Antioxidantes/metabolismo , Núcleo Celular/genética , Dano ao DNA/genética , DNA Mitocondrial/genética , Técnicas de Inativação de Genes , Glutationa/deficiência , Estágios do Ciclo de Vida/genética , Malária/tratamento farmacológico , Malária/genética , Estresse Oxidativo/genética , Plasmodium berghei/crescimento & desenvolvimento , Plasmodium berghei/patogenicidade , Tiorredoxinas/genética , Tiorredoxinas/metabolismoRESUMO
The development and survival of male germ cells depend on the antioxidant capacity of the seminiferous tubule. Glutathione (GSH) plays an important role in the antioxidant defenses of the spermatogenic epithelium. Autophagy can act as a pro-survival response during oxidative stress or nutrient deficiency. In this work, we evaluated whether autophagy is involved in spermatogonia-type germ cell survival during severe GSH deficiency. We showed that the disruption of GSH metabolism with l-buthionine-(S,R)-sulfoximine (BSO) decreased reduced (GSH), oxidized (GSSG) glutathione content, and GSH/GSSG ratio in germ cells, without altering reactive oxygen species production and cell viability, evaluated by 2',7'-dichlorodihydrofluorescein (DCF) fluorescence and exclusion of propidium iodide assays, respectively. Autophagy was assessed by processing the endogenous protein LC3I and observing its sub-cellular distribution. Immunoblot and immunofluorescence analysis showed a consistent increase in LC3II and accumulation of autophagic vesicles under GSH-depletion conditions. This condition did not show changes in the level of phosphorylation of AMP-activated protein kinase (AMPK) or the ATP content. A loss in S-glutathionylated protein pattern was also observed. However, inhibition of autophagy resulted in decreased ATP content and increased caspase-3/7 activity in GSH-depleted germ cells. These findings suggest that GSH deficiency triggers an AMPK-independent induction of autophagy in germ cells as an adaptive stress response.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Glutationa/metabolismo , Estresse Oxidativo/genética , Espermatogônias/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Trifosfato de Adenosina/biossíntese , Animais , Antioxidantes/metabolismo , Autofagia/genética , Caspases/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Glutationa/deficiência , Dissulfeto de Glutationa/metabolismo , Masculino , Camundongos , Propídio/administração & dosagem , Espécies Reativas de Oxigênio/metabolismo , Túbulos Seminíferos/crescimento & desenvolvimento , Túbulos Seminíferos/metabolismo , Espermatogônias/crescimento & desenvolvimentoRESUMO
Malignant glioma is a severe type of brain tumor with a poor prognosis and few options for therapy. The main chemotherapy protocol for this type of tumor is based on temozolomide (TMZ), albeit with limited success. Cisplatin is widely used to treat several types of tumor and, in association with TMZ, is also used to treat recurrent glioma. However, several mechanisms of cellular resistance to cisplatin restrict therapy efficiency. In that sense, enhanced DNA repair, high glutathione levels and functional p53 have a critical role on cisplatin resistance. In this work, we explored several mechanisms of cisplatin resistance in human glioma. We showed that cellular survival was independent of the p53 status of those cells. In addition, in a host-cell reactivation assay using cisplatin-treated plasmid, we did not detect any difference in DNA repair capacity. We demonstrated that cisplatin-treated U138MG cells suffered fewer DNA double-strand breaks and DNA platination. Interestingly, the resistant cells carried higher levels of intracellular glutathione. Thus, preincubation with the glutathione inhibitor buthionine sulfoximine (BSO) induced massive cell death, whereas N-acetyl cysteine, a precursor of glutathione synthesis, improved the resistance to cisplatin treatment. In addition, BSO sensitized glioma cells to TMZ alone or in combination with cisplatin. Furthermore, using an in vivo model the combination of BSO, cisplatin and TMZ activated the caspase 3-7 apoptotic pathway. Remarkably, the combined treatment did not lead to severe side effects, while causing a huge impact on tumor progression. In fact, we noted a remarkable threefold increase in survival rate compared with other treatment regimens. Thus, the intracellular glutathione concentration is a potential molecular marker for cisplatin resistance in glioma, and the use of glutathione inhibitors, such as BSO, in association with cisplatin and TMZ seems a promising approach for the therapy of such devastating tumors.
Assuntos
Neoplasias Encefálicas/patologia , Cisplatino/farmacologia , Dacarbazina/análogos & derivados , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Glioma/patologia , Glutationa/deficiência , Animais , Apoptose/efeitos dos fármacos , Butionina Sulfoximina/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA , Reparo do DNA/efeitos dos fármacos , Dacarbazina/farmacologia , Progressão da Doença , Feminino , Humanos , Camundongos Nus , Temozolomida , Proteína Supressora de Tumor p53/metabolismoRESUMO
AIMS: Liver preconditioning against ischemia-reperfusion (IR) injury is a major area of experimental research, in which regulation of gene expression with cytoprotective responses due to transient oxidative stress development has been reported. Considering that significant cytoprotection occurs after exposure to low levels of iron (Fe), we tested the hypothesis that sub-chronic administration of Fe to rats underlying transient oxidative stress preconditions the liver against IR injury. MAIN METHODS: Animals received six doses (50 mg Fe-dextran/kg ip) every second day during 10 days, before partial IR (vascular clamping) or sham laparotomy (control). Transient oxidative stress was defined by liver glutathione and protein carbonyl contents (24, 48, and 72 h after Fe treatment). Plasma and liver Fe status and ferritin content (western blot) were assessed in animals not subjected to IR. Liver injury and inflammatory response were evaluated by serum transaminases, liver morphology and serum TNF-α. Fe preconditioning against IR injury was correlated with liver glutathione content and the redox-sensitive NF-κB signaling pathway (EMSA) and western blot analysis of haptoglobin. KEY FINDINGS: Significant hepatoprotection against IR injury, underlying transient oxidative stress and enhancement in the total and labile Fe pools, was achieved by Fe administration. Abrogation of IR injury is related to reduced TNF-α response (91%), abolishment of the IR-induced liver glutathione depletion and recovery of the NF-κB signaling pathway (75%), lost during IR. SIGNIFICANCE: Sub-chronic Fe administration protects the liver against IR injury through antioxidant and anti-inflammatory responses, with recovery of NF-κB activation and related acute-phase response signaling.
Assuntos
Ferro/farmacologia , Precondicionamento Isquêmico/métodos , Fígado/irrigação sanguínea , Traumatismo por Reperfusão/prevenção & controle , Reação de Fase Aguda/metabolismo , Animais , Modelos Animais de Doenças , Glutationa/deficiência , Glutationa/metabolismo , Ferro/análise , Ferro/metabolismo , Fígado/metabolismo , Fígado/patologia , Masculino , NF-kappa B/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Glutathione serves the function of providing reducing equivalents for the maintenance of oxidant homeostasis, and besides it plays roles in intra- and intercellular signaling in the brain. Our purpose was to test the effects of depleting tissue glutathione by diethylmaleate (5.3 mmol/kg, intraperitoneal) on brain antioxidant metabolism, nerve growth factor levels, and cognitive performance in rats. Six hours after the treatment, glutathione level in the hippocampus dropped down to 30% of the mean value of vehicle-treated animals and glutathione peroxidase activity also declined. Twenty-four hours after the injection the values had been partially restored. Moreover, the hippocampal and cortical levels of nerve growth factor protein did not change in response to diethylmaleate treatment. Glutathione depletion did not influence the performance of animals in the step-through passive avoidance test, but impairs acquisition in the Morris water maze when given before training. However, when diethylmaleate was administered after acquisition in the same paradigm, it did not affect the retention tested at the following day. Our results suggest that glutathione status is important during acquisition, but not for retention, of spatial memory in maze tasks and they support the hypothesis of the oxidant/antioxidant equilibrium as a key piece acting in the regulation of brain function.
Assuntos
Comportamento Animal/fisiologia , Encéfalo/metabolismo , Glutationa/fisiologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Aprendizagem da Esquiva/fisiologia , Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Lobo Frontal/efeitos dos fármacos , Lobo Frontal/metabolismo , Glutationa/antagonistas & inibidores , Glutationa/deficiência , Glutationa Peroxidase/antagonistas & inibidores , Habituação Psicofisiológica/efeitos dos fármacos , Habituação Psicofisiológica/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Maleatos/farmacologia , Aprendizagem em Labirinto/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Retenção Psicológica/efeitos dos fármacos , Percepção Espacial/efeitos dos fármacos , Percepção Espacial/fisiologia , NataçãoRESUMO
Se estandarizaron las técnicas de actividad de g -glutamil cisteil sintetasa y glutatión sintetasa con el objetivo de estudiar los pacientes con deficiencia congénita de glutatión reducido. Los valores normales encontrados en nuestro laboratorio no presentaron diferencias significativas con los señalados por otros autores. Se estudiaron varios miembros de una familia con deficiencia de glutatión reducido. Los estudios bioquímicos excluyeron la posible deficiencia de glucosa-6-fosfato deshidrogenasa. En el propósito y un hermano (G.D.R.) se encontró deficiencia de glutatión sintetasa. Ambos presentan una anemia hemolítica congénita no esferocítica, con hemólisis crónica e íctero que se exacerba en el transcurso de procesos infecciosos y también litiasis vesicular. Ninguno presentó acidosis metabólica ni trastornos neurológicos progresivos, por lo que ambos son portadores de la forma benigna de la enfermedad. En el padre y otro hermano, los resultados del estudio hematológico y bioquímico indican que posiblemente son heterocigóticos para la deficiencia de esta enzima. Esta es la primera familia con deficiencia de glutatión sintetasa encontrada en nuestra población
Assuntos
Humanos , Feminino , Adulto , Anemia Hemolítica Congênita/genética , Glutamato-Cisteína Ligase/genética , Glutationa Sintase/deficiência , Glutationa Sintase/genética , Glutationa/deficiênciaRESUMO
Existem várias evidências de que a glutationa reduzida (GSH)atua na destruição de intermediários reativos de oxigênio e de outros radicais livres que são constantemente formados sob condições normais ou após administração de certas drogas, raios X e oxigênio. O nível celular da GSH é regulado por processos que compreendem o sistema de captação de aminoácidos através da membrana, o grupo de enzimas intracelulares envolvidas na síntese e regulação por feedback e o processo de exportação do tripeptídeo. A regulação da GSH intracelular pode ocorrer pela glutationa oxidada (GSSG) indesejável. São de grande interesse terapêutico os estudos com agentes que, de alguma forma, aumentam ou diminuem o nível da GSH. Em geral, o aumento da GSH é prejudicial ao tratamento químio ou radioterápico do câncer e o tratamento com butionina sulfoximina (BSO), promovendo o decréscimo do nível celular da GSH, pode aumentar a sensibilidade tumoral a drogas anti-câncer e à radioterapia. Por outro lado, os estudos com agentes que aumentam o nível de GSH podem contribuir para o aumento da proteção contra o estresse oxidativo.
Assuntos
Glutationa/análise , Glutationa/deficiência , Glutationa/metabolismo , Antioxidantes/análise , Antioxidantes/metabolismo , Estresse Oxidativo/fisiologia , Glutationa Redutase/fisiologia , Glutationa Redutase/metabolismoRESUMO
A 7-year-old boy with deficient activity of methylmalonyl coenzyme A mutase (mut-methylmalonic acidemia) was seen in severe metabolic crisis. After hemodialysis and clearance of toxic metabolites, severe lactic acidosis persisted with multiorgan failure. Glutathione deficiency was noted and high-dose ascorbate therapy (120 mg/kg) commenced. Glutathione deficiency may contribute to the lactic acidosis observed during decompensation in patients with methylmalonic acidemia.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/complicações , Ácido Ascórbico/administração & dosagem , Glutationa/deficiência , Ácido Metilmalônico/sangue , Acidose Láctica/etiologia , Acidose Láctica/terapia , Doença Aguda , Erros Inatos do Metabolismo dos Aminoácidos/terapia , Criança , Humanos , Masculino , Diálise RenalRESUMO
Debido a la alarmante progresión del SIDA en todo el planeta, el virus que lo causa -HIV human immuno-deficiency virus- ha sido, hasta el presente, el más estudiado en la historia de la medicina, con lo cual puede decirse que existe un extenso conocimiento respecto de su estructura y reproducción. Mediante el microscopio electrónico de alta resolución, se determinó que el HIV posee una constitución casi esférica, y que su corteza externa, o cápsula, es semejante a la de cualquier membrana celular, vale decir que está constituida por una doble capa lipídica regularmente atravesada por moléculas proteicas que constituyen el sistema de histocompatibilidad. Otras moléculas de naturaleza virósica formadas por glucoproteínas, se proyectan fuera de la cápsula en forma de espículas y se denomina g120, la porción externa y gp41, la que se halla sumergida en la membrana. Debajo de la membrana existe una capa de matriz proteica llamada p17 que, a su vez, rodea el núcleo del virus. Este último es una proteína (p24), que dispuesta en forma de cono truncado, envuelve el material genético del HIV formado por dos cadenas de RNA de 9200 nucleótidos. La presencia del RNA (ácido ribonucleico) en lugar de DNA (ácido desoxiribonucleico), le confiere el carácter de retrovirus. Unido al RNA se encuentran numerosas enzimas denominadas transcriptasa reversa, proteasa y ribonucleasa (Fig. 1) (AU)