RESUMO
Human life expectancy and welfare has decreased because of the increase in environmental stressors in the air. An environmental stressor is a natural or human-made component present in our environment that upon reaching an organic system produces a coordinated response. This response usually involves a modification of the metabolism and physiology of the system. Inhaled environmental stressors damage the airways and lung parenchyma, producing irritation, recruitment of inflammatory cells, and oxidative modification of biomolecules. Oxidatively modified biomolecules, their degradation products, and adducts with other biomolecules can reach the systemic circulation, and when found in higher concentrations than normal they are considered to be biomarkers of systemic oxidative stress and inflammation. We classify them as metabolic stressors because they are not inert compounds; indeed, they amplify the inflammatory response by inducing inflammation in the lung and other organs. Thus the lung is not only the target for environmental stressors, but it is also the source of a number of metabolic stressors that can induce and worsen pre-existing chronic inflammation. Metabolic stressors produced in the lung have a number of effects in tissues other than the lung, such as the brain, and they can also abrogate the mechanisms of immunotolerance. In this review, we discuss recent published evidence that suggests that inflammation in the lung is an important connection between air pollution and chronic inflammatory diseases such as autoimmunity and neurodegeneration, and we highlight the critical role of metabolic stressors produced in the lung. The understanding of this relationship between inhaled environmental pollutants and systemic inflammation will help us to: (1) understand the molecular mechanism of environment-associated diseases, and (2) find new biomarkers that will help us prevent the exposure of susceptible individuals and/or design novel therapies.
Assuntos
Poluentes Atmosféricos/toxicidade , Autoimunidade/efeitos dos fármacos , Inflamação/induzido quimicamente , Exposição por Inalação/efeitos adversos , Degeneração Neural/induzido quimicamente , Autoimunidade/genética , Bronquite Crônica/induzido quimicamente , Bronquite Crônica/genética , Doença Crônica , Predisposição Genética para Doença/etiologia , Humanos , Inflamação/genética , Modelos Biológicos , Degeneração Neural/genética , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologiaRESUMO
Oxidative damage is strongly implicated in the pathogenesis of neurodegenerative diseases including Alzheimer's disease, amyotrophic lateral sclerosis, Huntington's disease, Parkinson's disease and stroke (brain ischemia/reperfusion injury). The availability of transgenic and toxin-inducible models of these conditions has facilitated the preclinical evaluation of putative antioxidant agents ranging from prototypic natural antioxidants such as vitamin E (alpha-tocopherol) to sophisticated synthetic free radical traps and catalytic oxidants. Literature review shows that antioxidant therapies have enjoyed general success in preclinical studies across disparate animal models, but little benefit in human intervention studies or clinical trials. Recent high-profile failures of vitamin E trials in Parkinson's disease, and nitrone therapies in stroke, have diminished enthusiasm to pursue antioxidant neuroprotectants in the clinic. The translational disappointment of antioxidants likely arises from a combination of factors including failure to understand the drug candidate's mechanism of action in relationship to human disease, and failure to conduct preclinical studies using concentration and time parameters relevant to the clinical setting. This review discusses the rationale for using antioxidants in the prophylaxis or mitigation of human neurodiseases, with a critical discussion regarding ways in which future preclinical studies may be adjusted to offer more predictive value in selecting agents for translation into human trials.
Assuntos
Antioxidantes/metabolismo , Antioxidantes/uso terapêutico , Doenças do Sistema Nervoso Central/tratamento farmacológico , Doenças do Sistema Nervoso Central/metabolismo , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Esclerose Lateral Amiotrófica/tratamento farmacológico , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Humanos , Doença de Huntington/tratamento farmacológico , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Estresse Oxidativo/efeitos dos fármacos , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/metabolismo , Acidente Vascular Cerebral/patologiaRESUMO
The objective of this study was to determine the composition and content of sesamin and desmethyl tocopherols such as alpha-tocopherol (alphaT), delta-tocopherol (deltaT) and gamma-tocopherol (gammaT) in seeds of sesame (Sesamum indicum L.) for 11 genotypes conserved in the United States Department of Agriculture (USDA), Agricultural Research Service (ARS) and Plant Genetic Resources Conservation Unit (PGRCU) in Griffin, Georgia, USA. Seed accessions studied were collections from eight countries worldwide, including one landrace from Thailand and two cultivars from Texas, USA. Novel methodologies and analytical techniques described herein consisted of reverse-phase high-performance liquid chromatography (HPLC) connected in series with two detection systems specific for each analyte class. Photodiode array detection was employed for sesamin analysis and electrochemical array detection was used in the determination of tocopherols. A preliminary study was conducted to assess sesamin levels in 2003 and tocopherol levels in 2004 from sesame seed samples conserved at the USDA, ARS and PGRCU. In 2005, sesame seed samples were grown, harvested and evaluated for sesamin as well as tocopherol levels. The overall results (n = 3) showed that sesamin, alphaT, deltaT and gammaT levels were 0.67-6.35 mg/g, 0.034-0.175 microg/g, 0.44-3.05 microg/g and 56.9-99.3 microg/g respectively, indicating that the sesame seed accessions contained higher levels of sesamin and gammaT compared with alphaT and deltaT. Statistical analysis was conducted and significant differences were observed among the 11 different sesame genotypes. This suggests that genetic, environmental and geographical factors influence sesamin and desmethyl tocopherol content.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Dioxóis/análise , Eletroquímica/métodos , Lignanas/análise , Sementes/química , Sesamum/química , Espectrofotometria Ultravioleta/métodos , Tocoferóis/análise , Coleta de Dados , Genótipo , Sesamum/genéticaRESUMO
The central nervous system (CNS) presents both challenges and opportunities to researchers of redox biochemistry. The CNS is sensitive to oxidative damage during aging or disease; excellent transgenic models of specific neurodegenerative diseases have been created that reproduce oxidative stress components of the corresponding human disorder. Mouse models of familial amyotrophic lateral sclerosis (ALS) based on overexpressed mutant human Cu, Zn-superoxide dismutase (SOD1) are cases in point. These animals experience predictably staged, age-dependent motor neuron degeneration with profound cellular and biochemical damage to nerve fibers and spinal cord tissue. Severe protein and lipid oxidation occurs in these animals, apparently as an indirect consequence of protein aggregation or cytopathic protein-protein interactions, as opposed to aberrant redox catalysis by the mutant enzyme. Recent studies of G93A-SOD1 mice and rats suggest that oxidative damage is part of an unmitigated neuroinflammatory reaction, possibly arising in combination from mitochondrial dysfunction plus pathophysiologic activation of both astrocytes and microglia. Lesions to redox signal-transduction pathways in mutant SOD1+ glial cells may stimulate broad-spectrum upregulation of proinflammatory genes, including arachidonic acid-metabolizing enzymes [e.g., cyclooxygenase-II (COX-II) and 5-lipoxygenase (5LOX)]; nitric oxide synthase (NOS) isoforms; cytokines (particularly tumor necrosis factor alpha, TNF-alpha); chemokines; and immunoglobulin Fc receptors (FcgammaRs). The integration of these processes creates a paracrine milieu inconsistent with healthy neural function. This review summarizes what has been learned to date from studies of mutant SOD1 transgenic animals and demonstrates that the G93A-SOD1 mouse in particular is a robust laboratory for the study of neuroinflammation and redox biochemistry.
Assuntos
Esclerose Lateral Amiotrófica/metabolismo , Modelos Animais de Doenças , Doenças Neurodegenerativas/metabolismo , Estresse Oxidativo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Animais , Humanos , Inflamação , Camundongos , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Superóxido Dismutase/genéticaRESUMO
Detailed study of glial inflammation has been hindered by lack of cell culture systems that spontaneously demonstrate the "neuroinflammatory phenotype". Mice expressing a glycine --> alanine substitution in cytosolic Cu, Zn-superoxide dismutase (G93A-SOD1) associated with familial amyotrophic lateral sclerosis (ALS) demonstrate age-dependent neuroinflammation associated with broad-spectrum cytokine, eicosanoid and oxidant production. In order to more precisely study the cellular mechanisms underlying glial activation in the G93A-SOD1 mouse, primary astrocytes were cultured from 7 day mouse neonates. At this age, G93A-SOD1 mice demonstrated no in vivo hallmarks of neuroinflammation. Nonetheless astrocytes cultured from G93A-SOD1 (but not wild-type human SOD1-expressing) transgenic mouse pups demonstrated a significant elevation in either the basal or the tumor necrosis alpha (TNFalpha)-stimulated levels of proinflammatory eicosanoids prostaglandin E2 (PGE2) and leukotriene B4 (LTB4); inducible nitric oxide synthase (iNOS) and *NO (indexed by nitrite release into the culture medium); and protein carbonyl products. Specific cytokine- and TNFalpha death-receptor-associated components were similarly upregulated in cultured G93A-SOD1 cells as assessed by multiprobe ribonuclease protection assays (RPAs) for their mRNA transcripts. Thus, endogenous glial expression of G93A-SOD1 produces a metastable condition in which glia are more prone to enter an activated neuroinflammatory state associated with broad-spectrum increased production of paracrine-acting substances. These findings support a role for active glial involvement in ALS and may provide a useful cell culture tool for the study of glial inflammation.
RESUMO
Our recent studies have demonstrated that generation of ROS is associated with choline deficiency (CD)-induced apoptosis in CWSV-1 cells, an immortalized rat hepatocyte that becomes tumorigenic by stepwise culturing in decreasing levels of choline. In the present study, we investigated the effect of CD on loss of mitochondrial membrane potential (MMP), using the JC-1 probe by FASCAN assay. Our data demonstrate that MMP in CD-cultured cells was decreased in a time- and dose-dependent manner and that significant disruption occurred at 24 h, relative to high choline (HC, 70 microM) cultured cells. In order to investigate further the relationship among the CD-induced ROS, MMP collapse, and apoptosis, we examined the effects of different inhibitors on ROS production, MMP disruption, and apoptosis in CD or HC-cultured CWSV-1 cells. These data indicate that the disruption of MMP is an upstream event in CD-induced apoptosis, and mitochondrial dysfunction plays a key role in mediating CD-induced apoptosis in CWSV-1 cells.
Assuntos
Apoptose , Colina/metabolismo , Hepatócitos/patologia , Mitocôndrias/patologia , Animais , Compostos de Benzil/farmacologia , Western Blotting , Caspases/metabolismo , Separação Celular , Células Cultivadas , Ciclosporina/farmacologia , Fragmentação do DNA , Transporte de Elétrons , Inibidores Enzimáticos/farmacologia , Citometria de Fluxo , Radicais Livres , Hepatócitos/metabolismo , Hidrocarbonetos Fluorados/farmacologia , Neoplasias Hepáticas/metabolismo , Potenciais da Membrana , Mitocôndrias/metabolismo , Ratos , Espécies Reativas de Oxigênio , Rotenona/farmacologia , Fatores de TempoRESUMO
PURPOSE: Inorganic catalytic nanoceria or cerium oxide nanoparticles (CeNPs) are bona fide antioxidants that possess regenerative radical scavenging activities in vitro. Previously, we demonstrated that CeNPs had neuroprotective and anti-angiogenic properties in rodent retinal degeneration and neovascularization models. However, the cellular mechanisms and duration of the catalytic activity of CeNPs in preventing photoreceptor cell loss are still unknown. In this study, we sought to answer these questions using the P23H-1 rat, an autosomal dominant retinitis pigmentosa (adRP) model. METHODS: A single dose of either saline or CeNPs was delivered intravitreally into the eyes of P23H-1 rats at 2-3 weeks of age. Retinal functions were examined at 3 to 7 weeks post injection. We quantified retinal proteins by Western blot analyses and counted the number of apoptotic (TUNEL+) profiles in the outer nuclear layer (ONL) of retinal sections. We measured free 8-isoprostanes to quantify lipid peroxidation in retinal tissues. RESULTS: We observed increased rod and cone cell functions up to three weeks post injection. Apoptotic cells were reduced by 46%, 56%, 21%, and 24% at 3, 7, 14, 21 days, respectively, after CeNPs injection compared to saline. Additionally, reduction of lipid peroxidation in the retinas of CeNPs-treated vs saline-treated animals was detected 14 days post injection. CONCLUSIONS: We validated that CeNPs were effective in delaying loss of photoreceptor cell function in an adRP rat model. This represents the fourth rodent retinal disease model that shows delay in disease progression after a single application of CeNPs. We further demonstrated that CeNPs slowed the rate of photoreceptor cell death. We deduced that the catalytic activity of CeNPs in vivo in this rat model to be undiminished for at least 7 days and then declined over the next 14 days after CeNPs administration.
Assuntos
Cério/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Células Fotorreceptoras de Vertebrados/efeitos dos fármacos , Retinose Pigmentar/tratamento farmacológico , Animais , Antioxidantes/administração & dosagem , Apoptose/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Injeções Intravítreas , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Degeneração Neural/patologia , Degeneração Neural/prevenção & controle , Estresse Oxidativo/efeitos dos fármacos , Células Fotorreceptoras de Vertebrados/patologia , Células Fotorreceptoras de Vertebrados/fisiologia , Ratos , Ratos Mutantes , Células Fotorreceptoras Retinianas Cones/efeitos dos fármacos , Células Fotorreceptoras Retinianas Cones/patologia , Células Fotorreceptoras Retinianas Cones/fisiologia , Células Fotorreceptoras Retinianas Bastonetes/efeitos dos fármacos , Células Fotorreceptoras Retinianas Bastonetes/patologia , Células Fotorreceptoras Retinianas Bastonetes/fisiologia , Retinose Pigmentar/patologia , Retinose Pigmentar/fisiopatologiaRESUMO
Choline deficiency (CD) is involved in hepatocellular carcinoma and CD-induced apoptosis may be implicated in cellular malignant transformation. In this report, we studied the effects of choline deficiency on generation of reactive oxygen species (ROS) using the fluorescent probe dichlorodihydrofluorescein diacetate and the possible role of ROS on CD-induced apoptosis in cultured CWSV-1 cells, an immortalized rat hepatocyte. This cell line is reported to become tumorigenic by step-wise culturing in lower levels of choline. Our data demonstrate that CD induces a time- and dose-dependent increase in ROS in CWSV-1 cells. The increase in ROS production may be related to dysfunction of the mitochondrial respiratory chain. Our data also demonstrated that ROS generation occurred before CD-induced apoptosis, suggesting ROS may play a key role in signaling CD-induced apoptosis in CWSV-1 cells.
Assuntos
Apoptose , Deficiência de Colina/metabolismo , Deficiência de Colina/patologia , Hepatócitos/metabolismo , Hepatócitos/patologia , Espécies Reativas de Oxigênio/metabolismo , Animais , Apoptose/efeitos dos fármacos , Caspase 3 , Caspases/metabolismo , Linhagem Celular , Colina/farmacologia , Mitocôndrias Hepáticas/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , RatosRESUMO
Vitamin E (alpha-tocopherol or alphaT) has long been recognized as a classic free radical scavenging antioxidant whose deficiency impairs mammalian fertility. In actuality, alpha-tocopherol is one member of a class of phytochemicals that are distinguished by varying methylation of a chroman head group. Early studies conducted between 1922 and 1950 indicated that alpha-tocopherol was specific among the tocopherols in allowing fertility of laboratory animals. The unique vitamin action of alphaT, combined with its prevalence in the human body and the similar efficiency of tocopherols as chain-breaking antioxidants, led biologists to almost completely discount the "minor" tocopherols as topics for basic and clinical research. Recent discoveries have forced a serious reconsideration of this conventional wisdom. New and unexpected biological activities have been reported for the desmethyl tocopherols, such as gamma-tocopherol, and for specific tocopherol metabolites, most notably the carboxyethyl-hydroxychroman (CEHC) products. The activities of these other tocopherols do not map directly to their chemical antioxidant behavior but rather reflect anti-inflammatory, antineoplastic, and natriuretic functions possibly mediated through specific binding interactions. Moreover, a nascent body of epidemiological data suggests that gamma-tocopherol is a better negative risk factor for certain types of cancer and myocardial infarction than is a alpha-tocopherol. The potential public health implications are immense, given the extreme popularity of alphaT supplementation which can unintentionally deplete the body of gamma-tocopherol. These findings may or may not signal a major paradigm shift in free radical biology and medicine. The data argue for thorough experimental and epidemiological reappraisal of desmethyl tocopherols, especially within the contexts of cardiovascular disease and cancer biology.
Assuntos
Cromanos/metabolismo , Cromanos/farmacologia , gama-Tocoferol/metabolismo , gama-Tocoferol/farmacologia , Animais , Anti-Inflamatórios/metabolismo , Anti-Inflamatórios/farmacologia , Doenças do Sistema Nervoso Autônomo/metabolismo , Doenças do Sistema Nervoso Autônomo/prevenção & controle , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/prevenção & controle , Cromanos/química , Humanos , Neoplasias/epidemiologia , Neoplasias/prevenção & controle , gama-Tocoferol/síntese química , gama-Tocoferol/químicaRESUMO
Cerium oxide nanoparticles (nanoceria) possess catalytic and regenerative radical scavenging activities. The ability of nanoceria to maintain cellular redox balance makes them ideal candidates for treatment of retinal diseases whose development is tightly associated with oxidative damage. We have demonstrated that our stable water-dispersed nanoceria delay photoreceptor cell degeneration in rodent models and prevent pathological retinal neovascularization in vldlr mutant mice. The objectives of the current study were to determine the temporal and spatial distributions of nanoceria after a single intravitreal injection, and to determine if nanoceria had any toxic effects in healthy rat retinas. Using inductively-coupled plasma mass spectrometry (ICP-MS), we discovered that nanoceria were rapidly taken up by the retina and were preferentially retained in this tissue even after 120 days. We also did not observe any acute or long-term negative effects of nanoceria on retinal function or cytoarchitecture even after this long-term exposure. Because nanoceria are effective at low dosages, nontoxic and are retained in the retina for extended periods, we conclude that nanoceria are promising ophthalmic therapeutics for treating retinal diseases known to involve oxidative stress in their pathogeneses.
Assuntos
Cério/administração & dosagem , Nanopartículas/administração & dosagem , Retina/efeitos dos fármacos , Retina/metabolismo , Animais , Catálise , Cério/química , Cério/farmacocinética , Cério/toxicidade , Eletrorretinografia , Sequestradores de Radicais Livres/administração & dosagem , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/farmacocinética , Sequestradores de Radicais Livres/toxicidade , Injeções Intravítreas , Nanopartículas/química , Nanopartículas/toxicidade , Oxirredução/efeitos dos fármacos , Estresse Oxidativo , Ratos , Distribuição TecidualRESUMO
Proteomic experiments were performed to identify novel glutathione (GSH) binding proteins expressed in the mammalian central nervous system. Bovine brain lysate was affinity purified using an immobilized glutathione-Sepharose column. Proteins that bound the immobilized glutathione were eluted with free glutathione and identified by one- and two-dimensional electrophoresis coupled with mass spectrometric analysis of tryptic fragments. Major proteins purified by this technique were glutathione S-transferase-mu (GST-mu) and GST-pi and lanthionine synthase C-like protein-1 (LanCL1). LanCL1 is a mammalian homologue of a prokaryotic enzyme responsible for the synthesis of thioether (lanthionine) cross-links within nascent polypeptide chains, yielding macrocyclic proteins with potent microbicidal activity. An antibody against LanCL1 was generated and applied to immunochemical studies of spinal cord tissue from SOD1G93A transgenic mice, a model for amyotrophic lateral sclerosis (ALS), wherein LanCL1 expression was found to be increased at presymptomatic stages of the disease. These results indicate LanCL1 is a glutathione binding protein possibly significant to neurodegenerative disease.
Assuntos
Glutationa/metabolismo , Hidroliases/isolamento & purificação , Complexos Multienzimáticos/isolamento & purificação , Receptores Acoplados a Proteínas G/metabolismo , Animais , Química Encefálica , Bovinos , Glutationa S-Transferase pi/isolamento & purificação , Glutationa Transferase/isolamento & purificação , Camundongos , Camundongos Transgênicos , Ligação Proteica , Proteômica/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em TandemRESUMO
Familial amyotrophic lateral sclerosis (FALS) is often caused by gain-of-function mutations in Cu,Zn-superoxide dismutase (SOD1). Multiprobe ribonuclease protection assays (RPAs) were used to investigate expression of 36 different cytokines and apoptosis-related genes in spinal cords of mice that ubiquitously express human SOD1 bearing a glycine (r) alanine substitution at residue 93 (G93A-SOD1). Mice were studied at late presymptomatic stage (80 days), and at 120 days when the animals experience severe hindlimb paralysis and accumulation of oxidatively modified proteins. Spinal cord tissue from G93A-SOD1 mice expressed a selective subset of macrophage-typical cytokines (monokines) including interleukin (IL)1alpha, IL1beta and IL1RA at 80 days increasing by 120 days. Contrastingly, T-cell derived cytokines (lymphokines) including IL2, IL3 and IL4 were detected at low levels in non-transgenic mice but these were not elevated in G93A-SOD1 mice even at 120 days. Apoptosis-related genes were generally unaffected at 80 days but multiple caspases and death receptor components were up-regulated at 120 days; the only exceptions being FADD and the tumor necrosis factor (TNF)alpha receptor p55 which was up-regulated at 80 days and increased further at 120 days. These data indicate that in the G93A-SOD1 mouse: (i) cytokine expression changes precede bulk protein oxidation and apoptosis gene expression; (ii) lymphocyte contributions to cytokine expression in FALS are likely minor; and (iii) TNFalpha and its receptors may link inflammation to apoptosis in ALS.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Esclerose Lateral Amiotrófica/genética , Apoptose/genética , Citocinas/genética , Medula Espinal/metabolismo , Superóxido Dismutase/genética , Animais , Antígenos CD/genética , Antígenos CD/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Caspases/biossíntese , Caspases/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Proteína de Domínio de Morte Associada a Fas , Perfilação da Expressão Gênica , Humanos , Linfocinas/biossíntese , Linfocinas/genética , Camundongos , Camundongos Transgênicos , Monocinas/genética , Monocinas/metabolismo , Atividade Motora , Ensaios de Proteção de Nucleases , Oxirredução , Proteínas/metabolismo , RNA Mensageiro/biossíntese , Receptores do Fator de Necrose Tumoral/genética , Receptores do Fator de Necrose Tumoral/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral , Regulação para CimaRESUMO
Our objective was to assess the anti-inflammatory effects of alpha-tocopherol, gamma-tocopherol, and their metabolites 2,5,7,8-tetramethyl-2-(beta-carboxyethyl)-6-hydroxychroman (alpha-CEHC) and 2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman (gamma-CEHC) in defined cell culture systems. Rat aortic endothelial cells and mouse microglial cultures were treated with tumor necrosis factor TNFalpha or bacterial lipopolysaccharide (LPS) and nitrite and prostaglandin E(2) (PGE(2)) were measured. alpha-CEHC suppressed TNFalpha-stimulated nitrite production in both cell types, whereas both CEHC derivatives inhibited LPS-stimulated microglial nitrite efflux. Both alpha-CEHC and gamma-CEHC inhibited microglial PGE(2) production, but neither alpha- nor gamma-tocopherol was effective at inhibiting cytokine-stimulated inflammatory processes. These results show that the anti-inflammatory effects of tocopherols are highly cell type-, stimulus-, and endpoint-dependent.
Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Células Endoteliais/efeitos dos fármacos , Microglia/efeitos dos fármacos , Tocoferóis/farmacologia , Animais , Células Cultivadas , Dinoprostona/metabolismo , Relação Dose-Resposta a Droga , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Lipopolissacarídeos/farmacologia , Camundongos , Microglia/citologia , Microglia/metabolismo , Nitritos/metabolismo , Ratos , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
Oxidative stress and quasi-inflammatory processes recently have been recognized as contributing factors in the pathogenesis of Alzheimer's disease (AD). Reactive nitrating species have specifically been implicated in AD based on immunochemical and instrumental detection of nitrotyrosine in AD brain protein. The significance of lipid-phase nitration has not been investigated in AD. This study documents a significant two- to threefold increase in the lipid nitration product 5-nitro-gamma-tocopherol in affected regions of the AD brain as determined by high-performance liquid chromatography with electrochemical detection. In a bioassay to compare the relative potency of alpha-tocopherol and gamma-tocopherol against nitrative stress, rat brain mitochondria were exposed to the peroxynitrite-generating compound SIN-1. The oxidation-sensitive Kreb's cycle enzyme alpha-ketoglutarate dehydrogenase was inactivated by SIN-1, in a manner that could be significantly attenuated by gamma-tocopherol (at <10 microM) but not by alpha-tocopherol. These data indicate that nitric oxide-derived species are significant contributors to lipid oxidation in the AD brain. The findings are discussed in reference to the neuroinflammatory hypothesis of AD and the possible role of gamma-tocopherol as a major lipid-phase scavenger of reactive nitrogen species.
Assuntos
Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Molsidomina/análogos & derivados , Espécies Reativas de Nitrogênio/metabolismo , gama-Tocoferol/análogos & derivados , gama-Tocoferol/metabolismo , gama-Tocoferol/farmacologia , Idoso , Idoso de 80 Anos ou mais , Antioxidantes/farmacologia , Encéfalo/citologia , Encéfalo/patologia , Feminino , Humanos , Complexo Cetoglutarato Desidrogenase/antagonistas & inibidores , Metabolismo dos Lipídeos , Masculino , Mitocôndrias/metabolismo , Molsidomina/farmacologia , Doadores de Óxido Nítrico/farmacologia , Espécies Reativas de Nitrogênio/antagonistas & inibidoresRESUMO
Familial forms of amyotrophic lateral sclerosis (ALS) can be caused by mutations in copper, zinc-superoxide dismutase (SOD1). Mice expressing SOD1 mutants demonstrate a robust neuroinflammatory reaction characterized, in part, by up-regulation of tumor necrosis factor alpha (TNFalpha) and its primary receptor TNF-RI. In an effort to identify small molecule inhibitors of neuroinflammation useful in treatment of ALS, a microglial culture system was established to identify TNFalpha antagonists. Walker EOC-20 microglia cells were stimulated with recombinant TNFalpha, with or without inhibitors, and the cell response was indexed by NO2- output. Three hundred and fifty-five rationally selected compounds were included in this bioassay. The arachidonic acid 5-lipoxygenase (5LOX) and tyrosine kinase inhibitor nordihydroguaiaretic acid (NDGA), a natural dicatechol, was one of the most potent non-cytotoxic antagonists tested (IC50 8 +/- 3 microm). Investigation of the G93A-SOD1 mouse model for ALS revealed increased message and protein levels of 5LOX at 120 days of age. Oral NDGA (2500 p.p.m.) significantly extended lifespan and slowed motor dysfunction in this mouse, when administration was begun relatively late in life (90 days). NDGA extended median total lifespan of G93A-SOD1 mice by 10%, and life expectancy following start of treatment was extended by 32%. Disease-associated gliosis and cleaved microtubule-associated tau protein, an indicator of axon damage, were likewise reduced by NDGA. Thus, TNFalpha antagonists and especially 5LOX inhibitors might offer new opportunities for treatment of ALS.
Assuntos
Inibidores de Lipoxigenase , Inibidores de Lipoxigenase/farmacologia , Masoprocol/farmacologia , Microglia/efeitos dos fármacos , Paralisia/tratamento farmacológico , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Administração Oral , Fatores Etários , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Northern Blotting/métodos , Western Blotting/métodos , Índice de Massa Corporal , Linhagem Celular , Curcumina/farmacologia , Relação Dose-Resposta a Droga , Interações Medicamentosas , Inibidores Enzimáticos/farmacologia , Ensaio de Imunoadsorção Enzimática/métodos , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Imuno-Histoquímica/métodos , Concentração Inibidora 50 , Inibidores de Lipoxigenase/uso terapêutico , Masoprocol/uso terapêutico , Camundongos , Camundongos Transgênicos/fisiologia , Microglia/fisiologia , Modelos Neurológicos , Atividade Motora/efeitos dos fármacos , Óxido Nítrico/metabolismo , Paralisia/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Teste de Desempenho do Rota-Rod/métodos , Medula Espinal/citologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Estatísticas não Paramétricas , Superóxido Dismutase/genética , Superóxido Dismutase/fisiologia , Sobrevida/fisiologia , Fator de Necrose Tumoral alfa/farmacologia , Proteínas tau/metabolismoRESUMO
Recent data indicate that certain pro-inflammatory cytokines are transcriptionally upregulated in the spinal cords of G93A-SOD1 mice, a model of amyotrophic lateral sclerosis (ALS). We previously showed that the receptor for tumor necrosis factor alpha (TNF-R1) was notably elevated at late presymptomatic as well as symptomatic phases of disease (J. Neurochem. 82 (2002) 365). We now extend these findings by showing that message for TNFalpha, as well as mRNA for interferon gamma (IFNgamma) and transforming growth factor beta1/2 (TGFbeta1, TGFbeta2), is simultaneously increased. Furthermore, TNFalpha protein is significantly increased in G93A-SOD1 mouse spinal cords, as are protein levels for interleukin-6 (IL6), IFNgamma, and the chemokines RANTES (CCL5) and KC. The interaction of TNFalpha, IL6, and IFNgamma proteins was modeled in vitro using Walker EOC-20 murine microglia with nitrite (NO(2)(-)) efflux as a quantitative index of cell response. TNFalpha alone caused robust NO(2)(-) flux, while IL6 had a lesser effect and neither IFNgamma nor IL1beta was active when applied singly. The TNFalpha stimulus was potently magnified in the presence of IL6 or IFNgamma. When applied in combination at very low concentrations, IFNgamma co-synergized with IL6 to produce a multiplicative increase in NO(2)(-) after stimulation with TNFalpha. Taken together, these data suggest that modest increases in multiple synergistic cytokines could produce a disproportionately severe activation of microglia within the degenerating spinal cord. Our data support a model wherein TNFalpha acts as a principal driver for neuroinflammation, while several co-stimulating cytokines and chemokines act to potentiate the TNFalpha effects.