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1.
J Nutr Health Aging ; 22(7): 837-846, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30080229

RESUMO

OBJECTIVES: To assess the effects of a combination of omega 3 essential fatty acids, green tea catechins, and ginsenosides on cognition and brain functioning in healthy older adults. DESIGN: Double-blind, placebo-controlled, crossover design randomized controlled trial with 26-day intervention phases and a 30-day washout period. SETTING: The Institute for Dementia Research and Prevention at the Pennington Biomedical Research Center. PARTICIPANTS: Ten independently-living, cognitively-healthy older adults (mean age: 67.3 + 2.01 years). INTERVENTION: Daily consumption of an investigational product (trade name "Cerbella TM") consisting of an emulsified liquid combination of standardized fish oil, panax ginseng extract, and green tea catechins in a flavored base of lecithin phospholipids optimized to maximize bioavailability of the active ingredients. MEASUREMENTS: Before and after supplementation with the investigational product or placebo, participants completed cognitive tests including the Mini Mental State Exam (MMSE), Stroop test, Digit Symbol Substitution Test (DSST), and Immediate and Delayed Recall tests, as well as functional magnetic resonance imaging (fMRI) during a standard cognitive task switching paradigm. RESULTS: Performance on the MMSE, Stroop test, and DSST increased significantly over one month of supplementation with the investigational product (one-sample t tests, p<.05) although differences between these changes and corresponding changes during supplementation with placebo were not significant (two-sample t tests, p>.05). During supplementation with the investigational product, brain activation during task performance increased significantly more than during supplementation with placebo in brain regions known to be activated by this task (anterior and posterior cingulate cortex). Functional connectivity during task execution between task regions (middle frontal gyrus and anterior cingulate cortex) increased significantly during supplementation with the investigational product, relative to placebo. Functional connectivity during rest between task regions (precentral gyrus and middle frontal gyrus) and default mode network regions (medial frontal gyrus and precuneus) decreased during supplementation with the investigational product relative to placebo, suggesting greater segregation of task and rest related brain activity. CONCLUSION: One-month supplementation with a combination of omega 3 essential fatty acids, green tea catechins, and ginsenosides was associated with suggestive changes in cognitive functioning as well as modification of brain activation and brain functional connectivity in cognitively healthy older adults.


Assuntos
Encéfalo/fisiologia , Catequina/farmacologia , Cognição/efeitos dos fármacos , Ácidos Graxos Essenciais/farmacologia , Ácidos Graxos Ômega-3/farmacologia , Óleos de Peixe/farmacologia , Extratos Vegetais/farmacologia , Idoso , Encéfalo/efeitos dos fármacos , Suplementos Nutricionais , Método Duplo-Cego , Feminino , Giro do Cíngulo/efeitos dos fármacos , Giro do Cíngulo/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Panax/química , Lobo Parietal/efeitos dos fármacos , Lobo Parietal/fisiologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/fisiologia , Descanso , Teste de Stroop , Análise e Desempenho de Tarefas , Chá/química
2.
Neurology ; 64(7): 1152-6, 2005 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-15824339

RESUMO

OBJECTIVE: To determine if increased levels of oxidative damage are present in the brains of persons with mild cognitive impairment (MCI), a condition that often precedes Alzheimer disease (AD). METHODS: The authors assessed the amount of protein carbonyls, thiobarbituric acid-reactive substances (TBARS), and malondialdehyde in the superior and middle temporal gyri (SMTG) and cerebellum of short postmortem interval and longitudinally evaluated normal subjects and those with MCI and early AD. RESULTS: Elevated levels of protein carbonyls (approximately 25%), malondialdehyde (approximately 60%), and TBARS (approximately 210%) were observed in the SMTG of individuals with MCI and early AD vs normal control subjects. The elevation in TBARS was associated with the numbers of neuritic but not diffuse plaques. Levels of protein carbonyls increased as delayed verbal memory performance declined. CONCLUSION: Oxidative damage occurs in the brain of subjects with mild cognitive impairment, suggesting that oxidative damage may be one of the earliest events in the onset and progression of Alzheimer disease.


Assuntos
Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Transtornos Cognitivos/metabolismo , Degeneração Neural/metabolismo , Estresse Oxidativo/fisiologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Doença de Alzheimer/fisiopatologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Transtornos Cognitivos/patologia , Transtornos Cognitivos/fisiopatologia , Progressão da Doença , Feminino , Radicais Livres/metabolismo , Humanos , Masculino , Malondialdeído/metabolismo , Transtornos da Memória/patologia , Transtornos da Memória/fisiopatologia , Transtornos da Memória/psicologia , Degeneração Neural/patologia , Degeneração Neural/fisiopatologia , Testes Neuropsicológicos , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Valor Preditivo dos Testes , Carbonilação Proteica/fisiologia , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , Regulação para Cima/fisiologia
3.
J Neurochem ; 78(6): 1315-24, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11579140

RESUMO

Microglia are activated in humans following infection with human immunodeficiency virus (HIV), and brain inflammation is thought to be involved in neuronal injury and dysfunction during HIV infection. Numerous studies indicate a role for the HIV regulatory protein Tat in HIV-related inflammatory and neurodegenerative processes, although the specific effects of Tat on microglial activation, and the signal transduction mechanisms thereof, have not been elucidated. In the present study, we document the effects of Tat on microglial activation and characterize the signal transduction pathways responsible for Tat's pro-inflammatory effects. Application of Tat to N9 microglial cells increased multiple parameters of microglial activation, including superoxide production, phagocytosis, nitric oxide release and TNF alpha release. Tat also caused activation of both p42/p44 mitogen activated protein kinase (MAPK) and NF kappa B pathways. Inhibitor studies revealed that Tat-induced NF kappa B activation was responsible for increased nitrite release, while MAPK activation mediated superoxide release, TNF alpha release, and phagocytosis. Lastly, pre-treatment of microglial cells with physiological concentrations of 17 beta-estradiol suppressed Tat-mediated microglial activation by interfering with Tat-induced MAPK activation. Together, these data elucidate specific components of the microglial response to Tat and suggest that Tat could contribute to the neuropathology associated with HIV infection through microglial promulgation of oxidative stress.


Assuntos
Estradiol/farmacologia , Produtos do Gene tat/farmacologia , Mediadores da Inflamação/farmacologia , Microglia/efeitos dos fármacos , Oxidantes/farmacologia , Animais , Linhagem Celular , Produtos do Gene tat/antagonistas & inibidores , Camundongos , Microglia/fisiologia , Proteínas Quinases Ativadas por Mitógeno/fisiologia , NF-kappa B/fisiologia , Transdução de Sinais
4.
Free Radic Biol Med ; 31(5): 574-84, 2001 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-11522442

RESUMO

Although the proteasome is responsible for the majority of intracellular protein degradation, and has been demonstrated to play a pivotal role in a diverse array of cellular activities, the role of the proteasome in the central nervous system is only beginning to be elucidated. Recent studies have demonstrated that proteasome inhibition occurs in numerous neurodegenerative conditions, and that proteasome inhibition is sufficient to induce neuron death, elevate intracellular levels of protein oxidation, and increase neural vulnerability to subsequent injury. The focus of this review is to describe what is currently known about proteasome biology in the central nervous system and to discuss the possible role of proteasome inhibition in the neurodegenerative process.


Assuntos
Encéfalo/enzimologia , Cisteína Endopeptidases/metabolismo , Inibidores Enzimáticos/farmacologia , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/metabolismo , Animais , Doenças Neurodegenerativas/enzimologia , Complexo de Endopeptidases do Proteassoma , Ratos , Espécies Reativas de Oxigênio
5.
J Neurochem ; 78(2): 413-6, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11461977

RESUMO

Glutamate transporters are involved in the maintenance of synaptic glutamate concentrations. Because of its potential neurotoxicity, clearance of glutamate from the synaptic cleft may be critical for neuronal survival. Inhibition of glutamate uptake from the synapse has been implicated in several neurodegenerative disorders. In particular, glutamate uptake is inhibited in Alzheimer's disease (AD); however, the mechanism of decreased transporter activity is unknown. Oxidative damage in brain is implicated in models of neurodegeneration, as well as in AD. Glutamate transporters are inhibited by oxidative damage from reactive oxygen species and lipid peroxidation products such as 4-hydroxy-2-nonenal (HNE). Therefore, we have investigated a possible connection between the oxidative damage and the decreased glutamate uptake known to occur in AD brain. Western blots of immunoprecipitated HNE-immunoreactive proteins from the inferior parietal lobule of AD and control brains suggest that HNE is conjugated to GLT-1 to a greater extent in the AD brain. A similar analysis of beta amyloid (Abeta)-treated synaptosomes shows for the first time that Abeta1-42 also increases HNE conjugation to the glutamate transporter. Together, our data provide a possible link between the oxidative damage and neurodegeneration in AD, and supports the role of excitotoxicity in the pathogenesis of this disorder. Furthermore, our data suggests that Abeta may be a possible causative agent in this cascade.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Aldeídos/farmacologia , Peptídeos beta-Amiloides/farmacologia , Encéfalo/metabolismo , Ácido Glutâmico/metabolismo , Neuroglia/metabolismo , Lobo Parietal/metabolismo , Fragmentos de Peptídeos/farmacologia , Transportadores de Cassetes de Ligação de ATP/efeitos dos fármacos , Idoso , Sistema X-AG de Transporte de Aminoácidos , Animais , Encéfalo/patologia , Córtex Cerebral/metabolismo , Reagentes de Ligações Cruzadas/farmacologia , Feminino , Humanos , Masculino , Neuroglia/patologia , Tamanho do Órgão , Oxirredução , Lobo Parietal/patologia , Ratos , Valores de Referência , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
6.
Biochemistry ; 40(8): 2548-54, 2001 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-11327877

RESUMO

Apolipoprotein E (apoE) plays an important role in the response to central nervous system injury. The e4 allele of apoE and amyloid beta-peptide (Abeta) are associated with Alzheimer's disease (AD) and may be central to the pathogenesis of this disorder. Recent studies demonstrate evidence for neurodegeneration and increased lipid peroxidation in transgenic mice lacking apoE (KO). In the current study, synaptosomes were prepared from apoE KO mice to determine the role of apoE in synaptic membrane structure and to determine susceptibility to oxidative damage by Abeta(1-40). ApoE KO mice exhibited structural modifications to lipid and protein components of synaptosomal membranes as determined by electron paramagnetic resonance in conjunction with lipid- and protein- specific spin labels. Incubation with 5 microM Abeta(1-40) resulted in more severe oxidative modifications to proteins and lipids in apoE KO synaptosomes as measured by protein carbonyls, an index of protein oxidation, and TBARs and protein-bound 4-hydroxynonenal (HNE), markers of lipid oxidation. Together, these data support a role for apoE in the modulation of oxidative injury and in the maintenance of synaptic integrity and are discussed with reference to alterations in AD brain.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/farmacologia , Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Fragmentos de Peptídeos/farmacologia , Sinaptossomos/química , Sinaptossomos/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Animais , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos/genética , Masculino , Fluidez de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/patologia , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
7.
J Neurochem ; 77(4): 1010-7, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11359866

RESUMO

Recent studies have demonstrated that inhibition of the proteasome, an enzyme responsible for the majority of intracellular proteolysis, may contribute to the toxicity associated with oxidative stress. In the present study we demonstrate that exposure to oxidative injury (paraquat, H(2)O(2), FeSO(4)) induces a rapid increase in reactive oxygen species (ROS), loss of mitochondrial membrane potential, inhibition of proteasome activity, and induction of cell death in neural SH-SY5Y cells. Application of proteasome inhibitors (MG115, epoxomycin) mimicked the effects of oxidative stressors on mitochondrial membrane potential and cell viability, and increased vulnerability to oxidative injury. Neural SH-SY5Y cells stably transfected with human HDJ-1, a member of the heat shock protein family, were more resistant to the cytotoxicity associated with oxidative stressors. Cells expressing increased levels of HDJ-1 displayed similar degrees of ROS formation following oxidative stressors, but demonstrated a greater preservation of mitochondrial function and proteasomal activity following oxidative injury. Cells transfected with HDJ-1 were also more resistant to the toxicity associated with proteasome inhibitor application. These data support a possible role for proteasome inhibition in the toxicity of oxidative stress, and suggest heat shock proteins may confer resistance to oxidative stress, by preserving proteasome function and attenuating the toxicity of proteasome inhibition.


Assuntos
Cisteína Endopeptidases/metabolismo , Proteínas de Choque Térmico/metabolismo , Complexos Multienzimáticos/metabolismo , Neurônios/fisiologia , Estresse Oxidativo/fisiologia , Inibidores de Proteases/farmacologia , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Proteínas de Choque Térmico HSP40 , Proteínas de Choque Térmico/genética , Humanos , Peróxido de Hidrogênio/toxicidade , Membranas Intracelulares/fisiologia , Cinética , Leupeptinas/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Mitocôndrias/fisiologia , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurotoxinas/toxicidade , Oligopeptídeos/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Paraquat/toxicidade , Complexo de Endopeptidases do Proteassoma , Espécies Reativas de Oxigênio/metabolismo , Proteínas Recombinantes/metabolismo , Transfecção
8.
Free Radic Biol Med ; 29(10): 1037-42, 2000 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-11084292

RESUMO

The autoxidation and enzymatic catabolism of dopamine results in the generation of reactive oxygen species (ROS), which may possibly contribute to oxidative stress in multiple neurodegenerative disorders. Recent studies indicate that proteasome inhibition occurs in numerous neurodegenerative conditions, possibly as the result of oxidative stress, although the effects of dopamine on proteasome activity have not been determined. In the present study we examined the effects of dopamine on proteasome activity in the neural PC12 cell line. Application of dopamine induced a dose- and time-dependent decrease in proteasome activity, which occurred prior to cell death. Application of an antioxidant (gluthathione monoethyl ester), monoamine oxidase inhibitors (deprenyl, clogyline, paragyline), or an inhibitor of dopamine uptake (nomifensine) attenuated dopamine toxicity and dopamine-induced proteasome impairment. Application of the proteasome inhibitor lactacystin increased the toxicity of dopamine and the levels of protein oxidation following administration of dopamine. Together, these data indicate that dopamine induces proteasome inhibition that is dependent, in part, on ROS and dopamine uptake, and suggest a possible role for proteasome inhibition in dopamine toxicity.


Assuntos
Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Dopamina/farmacologia , Complexos Multienzimáticos/metabolismo , Animais , Morte Celular/efeitos dos fármacos , Dopamina/metabolismo , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Estresse Oxidativo , Células PC12 , Complexo de Endopeptidases do Proteassoma , Ratos , Espécies Reativas de Oxigênio/metabolismo
9.
Endocrinology ; 141(10): 3646-56, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11014219

RESUMO

In the present study the effects of 17beta-estradiol on microglial activation are described. Estrogen replacement therapy has been associated with decreased severity of age-related neurodegenerative diseases such as Alzheimer's disease, and estrogens have potent immunosuppressive properties outside of the brain. To determine the role that microglial cells might play in estrogen-mediated neuroprotection, primary rat microglia and N9 microglial cell lines were treated with increasing doses of 17beta-estradiol before or during immunostimulation by lipopolysaccharide, phorbol ester, or interferon-gamma. Pretreatment with 17beta-estradiol, but not 17alpha-estradiol or progesterone, dose dependently attenuated microglial superoxide release and phagocytic activity. Additionally, 17beta-estradiol attenuated increases in inducible nitric oxide synthase protein expression, but did not alter nuclear factor-KB activation. The antiinflammatory effects of 17beta-estradiol were blocked by the antiestrogen ICI 182,780. Additionally, 17beta-estradiol induced rapid phosphorylation of the p42/p44 mitogen-activated protein kinase (MAP kinase), and the MAP kinase inhibitor PD 98059 blocked the antiinflammatory effects of 17beta-estradiol. Overall, these results suggest that estrogen receptor-dependent activation of MAP kinase is involved in estrogen-mediated antiinflammatory pathways in microglial cells. These results describe a novel mechanism by which estrogen may attenuate the progression of neurodegenerative disease and suggest new pathways for therapeutic intervention in clinical settings.


Assuntos
Anti-Inflamatórios/farmacologia , Estradiol/análogos & derivados , Estradiol/farmacologia , Microglia/efeitos dos fármacos , Microglia/fisiologia , Animais , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Antagonistas de Estrogênios/farmacologia , Flavonoides/farmacologia , Fulvestranto , Microglia/metabolismo , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , NF-kappa B/fisiologia , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II , Fagocitose/efeitos dos fármacos , Ratos , Receptores de Estrogênio/antagonistas & inibidores , Receptores de Estrogênio/metabolismo , Superóxidos/metabolismo
10.
J Cereb Blood Flow Metab ; 20(10): 1467-73, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11043909

RESUMO

Numerous studies indicate a role for oxidative stress in the neuronal degeneration and cell death that occur during ischemia-reperfusion injury. Recent data suggest that inhibition of the proteasome may be a means by which oxidative stress mediates neuronal cell death. In the current study, the authors demonstrate that there is a time-dependent decrease in proteasome activity, which is not associated with decreased expression of proteasome subunits, after cerebral ischemia-reperfusion injury. To determine the role of oxidative stress in mediating proteasome inhibition, ischemia-reperfusion studies were conducted in mice that either overexpressed the antioxidant enzyme glutathione peroxidase [GPX 1(+)], or were devoid of glutathione peroxidase activity (GPX -/-). After ischemia-reperfusion, GPX 1(+) mice displayed decreased infarct size, attenuated neurologic impairment, and reduced levels of proteasome inhibition compared with either GPX -/- or wild type mice. In addition, GPX 1(+) mice displayed lower levels of 4-hydroxynonenal-modified proteasome subunits after ischemia-reperfusion injury. Together, these data indicate that proteasome inhibition occurs during cerebral ischemia-reperfusion injury and is mediated, at least in part, by oxidative stress.


Assuntos
Isquemia Encefálica/metabolismo , Cisteína Endopeptidases/metabolismo , Complexos Multienzimáticos/metabolismo , Estresse Oxidativo/fisiologia , Traumatismo por Reperfusão/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Isquemia Encefálica/patologia , Glutationa Peroxidase/deficiência , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Camundongos , Camundongos Endogâmicos , Camundongos Transgênicos/genética , Complexos Multienzimáticos/antagonistas & inibidores , Complexo de Endopeptidases do Proteassoma , Traumatismo por Reperfusão/patologia
11.
J Neurosci Res ; 61(4): 436-42, 2000 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-10931530

RESUMO

This study demonstrates the ability of proteasome inhibitors (lactacystin, MG 115, MG 132) adenosine diphosphate to induce a time- and dose-dependent increase in poly-ADP-ribosylation (PAR) in the neural PC6 cell line, a subclone of PC12 cells. Elevated levels of PAR contribute to the toxicity associated with impaired proteasome activity, based on the ability of PAR inhibitors to ameliorate the toxicity associated with the application of lactacystin, MG 115, and MG 132. Proteasome inhibitors induced the accumulation of PAR and neuron death in primary hippocampal neuron cultures, which were both ameliorated by treatment with PAR inhibitors. Together, these data indicate a role for increased PAR in the toxicity associated with proteasome inhibition, and suggest that inhibitors of PAR may provide neuroprotection in conditions where proteasome inhibition occurs.


Assuntos
Cisteína Endopeptidases/efeitos dos fármacos , Inibidores de Cisteína Proteinase/farmacologia , Complexos Multienzimáticos/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Poli(ADP-Ribose) Polimerases/metabolismo , Animais , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Células Cultivadas , Embrião de Mamíferos , Hipocampo , Neurônios/metabolismo , Poli(ADP-Ribose) Polimerases/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma , Ratos , Ratos Sprague-Dawley
12.
J Neurochem ; 75(1): 436-9, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10854289

RESUMO

Inhibition of proteasome activity is sufficient to induce neuron degeneration and death; however, altered proteasome activity in a neurodegenerative disorder has not been demonstrated. In the present study, we analyzed proteasome activity in short-postmortem-interval autopsied brains from 16 Alzheimer's disease (AD) and nine age- and sex-matched controls. A significant decrease in proteasome activity was observed in the hippocampus and parahippocampal gyrus (48%), superior and middle temporal gyri (38%), and inferior parietal lobule (28%) of AD patients compared with controls. In contrast, no significant decrease in proteasome activity was observed in either the occipital lobe or the cerebellum. The loss of proteasome activity was not associated with a decrease in proteasome expression, suggesting that the proteasome may become inhibited in AD by a posttranslational modification. Together, these data indicate a possible role for proteasome inhibition in the neurodegeneration associated with AD.


Assuntos
Doença de Alzheimer/enzimologia , Cisteína Endopeptidases/metabolismo , Complexos Multienzimáticos/metabolismo , Idoso , Idoso de 80 Anos ou mais , Feminino , Hipocampo/enzimologia , Humanos , Masculino , Giro Para-Hipocampal/enzimologia , Lobo Parietal/enzimologia , Complexo de Endopeptidases do Proteassoma , Processamento de Proteína Pós-Traducional , Lobo Temporal/enzimologia
13.
Neuroscience ; 98(1): 149-56, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10858621

RESUMO

Neuron death and neuron degeneration occur in the CNS during the course of aging. Although multiple cellular alterations transpire during the aging process, those that mediate age-associated neuron death have not been identified. Recent evidence implicates oxidative stress as a possible means of neuron death and neuron degeneration during aging. In the present study, we demonstrate a marked decrease in multicatalytic proteasome activity in the spinal cord of Fisher 344 rats at 12, 24 and 28 months, compared with spinal cord tissue from 3-week- and 3-month-old animals. Application of oxidative injury (FeSO(4)) or the lipid peroxidation product 4-hydroxynonenal decreases multicatalytic proteasome activity in a time- and dose-dependent manner in a motor neuron cell line. Loss of multicatalytic proteasome activity occurs before the loss of multicatalytic proteasome immunoreactivity, with FeSO(4)- and 4-hydroxynonenal-mediated decreases ameliorated by the application of a cell permeable form of the antioxidant glutathione. Application of multicatalytic proteasome inhibitors, but not inhibitors of lysosomal proteases, induced neuron death that was attenuated by the caspase inhibitors benzyloxycarbonyl-Val-Ala-Asp-(O-methyl) fluoromethyl ketone or N-acetyl-Asp-Glu-Val-Asp-Cho (aldehyde). Together, these data suggest that multicatalytic proteasome inhibition occurs during aging of the spinal cord, possibly as the result of oxidative stress, and that multicatalytic proteasome inhibition may be causally related to neuron death.


Assuntos
Envelhecimento/metabolismo , Cisteína Endopeptidases/metabolismo , Neurônios Motores/citologia , Neurônios Motores/enzimologia , Complexos Multienzimáticos/metabolismo , Medula Espinal/citologia , Acetilcisteína/análogos & derivados , Acetilcisteína/farmacologia , Aldeídos/farmacologia , Clorometilcetonas de Aminoácidos/farmacologia , Animais , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Inibidores de Cisteína Proteinase/farmacologia , Glutationa/farmacologia , Ferro/farmacologia , Peroxidação de Lipídeos/fisiologia , Lisossomos/efeitos dos fármacos , Lisossomos/fisiologia , Camundongos , Neuroblastoma , Oligopeptídeos/farmacologia , Estresse Oxidativo/fisiologia , Complexo de Endopeptidases do Proteassoma , Ratos , Ratos Endogâmicos F344 , Espécies Reativas de Oxigênio/metabolismo , Medula Espinal/enzimologia , Células Tumorais Cultivadas
14.
Ann N Y Acad Sci ; 905: 132-41, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10818449

RESUMO

Lysophosphatidic acid (LPA) elicits a unique response in primary hippocampal neurons and sympathetic neuron-like cells, PC12 cells differentiated with nerve growth factor; LPA is cytotoxic. Treatment of rat hippocampal neurons with 50 microM LPA resulted in necrosis, as determined morphologically and by release of lactate dehydrogenase. Lower concentrations of LPA, 0.1, and 1 microM, induced neuronal apoptosis, as assessed by chromatin condensation, annexin V binding, TUNEL staining, and the caspase sensitivity of these events. In addition, 10 and 25 microM LPA induced apoptosis of PC12 cells. In order to define intracellular events associated with this neuronal apoptosis, protective agents were identified. Neurons and PC12 cells were protected against LPA-induced apoptosis by pretreatment with the antioxidant, propyl gallate, or with nitric oxide synthase inhibitors. PC12 cells were protected by insulin and insulin-like growth-factor-1 treatment. There is also evidence for mitochondrial participation in LPA-mediated apoptosis, including cyclosporin A-mediated protection. Thus, LPA-induced neuronal apoptosis is associated with mitochondrial alterations, the generation of reactive oxygen species and nitric oxide, and protection by pretreatment with a serum constituent, insulin-like growth factor 1.


Assuntos
Apoptose/efeitos dos fármacos , Lisofosfolipídeos/farmacologia , Neurônios/efeitos dos fármacos , Animais , Cálcio/metabolismo , Células Cultivadas , Necrose , Neurônios/metabolismo , Células PC12 , Ratos , Receptores de Glutamato/metabolismo , Transdução de Sinais
15.
J Neurochem ; 74(4): 1579-86, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10737615

RESUMO

Apolipoprotein E (apoE) is present in the brain and may contribute to neurophysiologic or neuropathologic events, depending on environmental and genetic influences. Recent studies indicate a role for apoE in synaptic plasticity and maintenance of synaptic membrane symmetry, suggesting that apoE may be involved in regulating synaptic homeostasis. In the present study, cerebrocortical synaptosomes were prepared from transgenic mice lacking apoE (apoE KO) to analyze the possible contribution of apoE toward maintaining homeostasis in synaptosomes. Synaptosomal preparations from apoE KO and wild-type mice exhibited similar basal levels of reactive oxygen species, mitochondrial function, and caspase activity; however, following application of amyloid beta-peptide [Abeta(1-40)], apoE KO synaptosomes displayed increased levels of oxidative stress, mitochondrial dysfunction, and caspase activation compared with synaptosomes from wild-type mice. Synaptosomal membranes from apoE KO mice were more fluid than wild-type synaptosomes and contained higher levels of thiobarbituric acid-reactive substances, consistent with elevated levels of lipid peroxidation occurring in the synapses of apoE KO mice. Together, these data are consistent with a role for apoE in maintaining homeostasis by attenuating oxidative stress, caspase activation, and mitochondrial homeostasis in synapses.


Assuntos
Peptídeos beta-Amiloides/farmacologia , Apolipoproteínas E/genética , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/enzimologia , Animais , Apolipoproteínas E/análise , Encéfalo/metabolismo , Química Encefálica/fisiologia , Caspases/metabolismo , Óxidos N-Cíclicos , Homeostase/efeitos dos fármacos , Peroxidação de Lipídeos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Microscopia Eletrônica , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Marcadores de Spin , Sinapses/efeitos dos fármacos , Sinapses/enzimologia , Sinapses/ultraestrutura
16.
Mech Ageing Dev ; 113(1): 61-70, 2000 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-10708250

RESUMO

Oxidative stress may contribute to the cellular alterations, which occur as the result of aging, and the nervous system is particularly vulnerable to aging associated oxidative injury. The multicatalytic proteasome (MCP) is responsible for the majority of protein degradation and is sensitive to oxidative stress. To determine if MCP activity is altered during aging, studies were conducted in multiple tissues from aged Fisher 344 rats. Analysis of heart, lung, kidney, and liver revealed decreased MCP activity in 12, 24, and 28 month old rats, compared with 3 week or 3 month old animals. The spinal cord, hippocampus, and cerebral cortex demonstrated age dependent decreases in MCP activity, but at no timepoint was MCP activity decreased in either the brain stem or cerebellum. Oxidative injury and the lipid oxidation product 4-hydroxynonenal caused decreased MCP activity in neural PC6 cells, while application of MCP inhibitors was sufficient to induce cell death in neural PC6 cells. Together, these data indicate a role for MCP inhibition in cellular dysfunction associated with aging and oxidative injury.


Assuntos
Envelhecimento/metabolismo , Cisteína Endopeptidases/metabolismo , Complexos Multienzimáticos/metabolismo , Estresse Oxidativo , Animais , Antioxidantes/farmacologia , Linhagem Celular , Sistema Nervoso Central/enzimologia , Peroxidação de Lipídeos , Masculino , Neurônios/efeitos dos fármacos , Neurônios/enzimologia , Complexo de Endopeptidases do Proteassoma , Ratos , Ratos Endogâmicos F344 , Distribuição Tecidual
17.
Exp Neurol ; 161(2): 621-30, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10686081

RESUMO

High-density lipoprotein (HDL) exists within the brain and is highly vulnerable to oxidative modifications. The focus of the present study was to determine the effect of HDL and oxidized HDL (oxHDL) upon neurons, astrocytes, and microglia. Administration of highly oxidized HDL, but not native, minimally, or moderately modified HDL resulted in a dose- and time-dependent increase in oxidative stress and death of cultured rat embryonic neurons. Astrocyte and microglia cultures treated with highly oxidized HDL displayed increased reactive oxygen species formation but no toxicity. Application of oxHDL exacerbated oxidative stress and neuron death induced by beta-amyloid peptide. Studies using pharmacological inhibitors implicate the involvement of calcium and reactive oxygen species in oxHDL-induced neuronal loss. Neural cells expressing increased levels of BCL-2 had decreased levels of oxidative stress and neuron death following exposure to oxHDL. Together, these data demonstrate that oxHDL increases oxidative stress in neurons, astrocytes, and microglia which ultimately culminate in neuron death.


Assuntos
Precursor de Proteína beta-Amiloide/toxicidade , Astrócitos/citologia , Hipocampo/citologia , Lipoproteínas HDL/farmacologia , Lipoproteínas LDL/toxicidade , Microglia/citologia , Neurônios/citologia , Estresse Oxidativo , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Sinergismo Farmacológico , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Embrião de Mamíferos , Humanos , Cinética , Microglia/efeitos dos fármacos , Microglia/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia , Ratos , Ratos Sprague-Dawley
18.
J Neurosci Res ; 58(6): 823-30, 1999 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-10583913

RESUMO

Increased levels of reactive oxygen species occur in neurodegenerative disorders and may promote neuron death. The lipid peroxidation product 4-hydroxynonenal (HNE) is increased in neurons following oxidative stress and promotes neuron death in vitro and in vivo. The present study examined the possibility that HNE can increase neuron vulnerability to oxidative stress. Application of low concentrations of HNE (50-500 nM) increased neuron death induced by beta-amyloid or glutamate when added within 3 hr of injury. In addition, treatment with HNE exacerbated mitochondrial reactive oxygen species formation and loss of mitochondrial membrane potential in response to beta-amyloid and glutamate. The ability to exacerbate oxidative stress, mitochondrial dysfunction, and neuron death appears to be specific to HNE, because application of other lipid peroxidation products had no effect. These data indicate a role for low levels of HNE in promoting reactive oxygen species accumulation and neuron degeneration by altering mitochondrial homeostasis. In addition, the present study indicates a possible mechanism for reactive oxygen species and lipid peroxidation toxicity in neurodegenerative conditions.


Assuntos
Aldeídos/efeitos adversos , Aldeídos/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Peptídeos beta-Amiloides/efeitos adversos , Animais , Técnicas de Cultura de Células , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Inibidores de Cisteína Proteinase/efeitos adversos , Inibidores de Cisteína Proteinase/metabolismo , Ácido Glutâmico/efeitos adversos , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Neurônios/citologia , Ratos , Ratos Sprague-Dawley
19.
J Neurosci ; 19(16): 7100-10, 1999 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-10436064

RESUMO

Apolipoprotein E (apoE)-related synthetic peptides, the 22 kDa N-terminal thrombin-cleavage fragment of apoE (truncated apoE), and full-length apoE have all been shown to exhibit neurotoxic activity under certain culture conditions. In the present study, protease inhibitors reduced the neurotoxicity and proteolysis of full-length apoE but did not block the toxicity of truncated apoE or a synthetic apoE peptide, suggesting that fragments of apoE may account for its toxicity. Additional experiments demonstrated that both truncated apoE and the apoE peptide elicit an increase in intracellular calcium levels and subsequent death of embryonic rat hippocampal neurons in culture. Similar effects on calcium were found when the apoE peptide was applied to chick sympathetic neurons. The rise in intracellular calcium and the hippocampal cell death caused by the apoE peptide were significantly reduced by receptor-associated protein, removal of extracellular calcium, or administration of the specific NMDA glutamate receptor antagonist MK-801. These results suggest that apoE may be a source of both neurotoxicity and calcium influx that involves cell surface receptors. Such findings strengthen the hypothesis that apoE plays a direct role in the pathology of Alzheimer's disease.


Assuntos
Apolipoproteínas E/farmacologia , Cálcio/metabolismo , Neurotoxinas/farmacologia , Fragmentos de Peptídeos/farmacologia , Animais , Apolipoproteínas E/química , Morte Celular/efeitos dos fármacos , Células Cultivadas , Embrião de Galinha , Maleato de Dizocilpina/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Humanos , Neurotoxinas/química , Inibidores de Proteases/farmacologia , Ratos , Estimulação Química
20.
J Neurochem ; 72(6): 2601-9, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10349872

RESUMO

Low-density lipoprotein (LDL) exists within the brain and is highly vulnerable to oxidative modifications. Once formed, oxidized LDL (oxLDL) is capable of eliciting cytotoxicity, differentiation, and inflammation in nonneuronal cells. Although oxLDL has been studied primarily for its role in the development of atherosclerosis, recent studies have identified a possible role for it in neurological disorders associated with oxidative stress. In the present study application of oxLDL, but not LDL, resulted in a dose- and time-dependent death of cultured rat embryonic neurons. Studies using pharmacological inhibitors implicate the involvement of calcium, reactive oxygen species, and caspases in oxLDL-induced neuronal death. Coapplication of oxLDL with either amyloid beta-peptide or glutamate, agents that enhance oxidative stress, resulted in increased neuronal death. Taken together, these data demonstrate that oxLDL induces neuronal death and implicate a possible role for oxLDL in conditions associated with increased levels of reactive oxygen species, including Alzheimer's disease.


Assuntos
Cálcio/metabolismo , Caspases/metabolismo , Lipoproteínas LDL/farmacologia , Neurônios/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Animais , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Inibidores de Cisteína Proteinase/farmacologia , Maleato de Dizocilpina/farmacologia , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Embrião de Mamíferos , Hipocampo/citologia , Hipocampo/metabolismo , Cinética , Neurônios/citologia , Neurônios/metabolismo , Oligopeptídeos/farmacologia , Ratos , Ratos Sprague-Dawley
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