RESUMO
Neuroinflammation is a major contributor to disease progression in Alzheimer's disease (AD) and is characterized by the activity of brain resident glial cells, in particular microglia cells. However, there is increasing evidence that peripheral immune cells infiltrate the brain at certain stages of AD progression and shape disease pathology. We recently identified CD8+ T-cells in the brain parenchyma of APP-PS1 transgenic mice being tightly associated with microglia as well as with neuronal structures. The functional role of CD8+ T-cells in the AD brain is however completely unexplored. Here, we demonstrate increased numbers of intra-parenchymal CD8+ T-cells in human AD post-mortem hippocampus, which was replicated in APP-PS1 mice. Also, aged WT mice show a remarkable infiltration of CD8+ T-cells, which was more pronounced and had an earlier onset in APP-PS1 mice. To address their functional relevance in AD, we successfully ablated the pool of CD8+ T-cells in the blood, spleen and brain from 12 months-old APP-PS1 and WT mice for a total of 4 weeks using an anti-CD8 antibody treatment. While the treatment at this time of disease stage did neither affect the cognitive outcome nor plaque pathology, RNAseq analysis of the hippocampal transcriptome from APP-PS1 mice lacking CD8+ T-cells revealed highly altered neuronal- and synapse-related gene expression including an up-regulation for neuronal immediate early genes (IEGs) such as the Activity Regulated Cytoskeleton Associated Protein (Arc) and the Neuronal PAS Domain Protein 4 (Npas4). Gene ontology enrichment analysis illustrated that the biological processes "regulation of neuronal synaptic plasticity" and the cellular components "postsynapses" were over-represented upon CD8+ T-cell ablation. Additionally, Kegg pathway analysis showed up-regulated pathways for "calcium signaling", "long-term potentiation", "glutamatergic synapse" and "axon guidance". Therefore, we conclude that CD8+ T-cells infiltrate the aged and AD brain and that brain CD8+ T-cells might directly contribute to neuronal dysfunction in modulating synaptic plasticity. Further analysis will be essential to uncover the exact mechanism of how CD8+ T-cells modulate the neuronal landscape and thereby contribute to AD pathology.
Assuntos
Doença de Alzheimer , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Encéfalo/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Modelos Animais de Doenças , Expressão Gênica , Camundongos , Camundongos Transgênicos , Presenilina-1/genética , Sinapses/metabolismoRESUMO
BACKGROUND: The pathophysiology of adhesion formation after abdominal and pelvic surgery is still largely unknown. The aim of the study was to investigate the role of macrophage polarization and the effect of peroxisome proliferator-activated receptor (PPAR) γ stimulation on adhesion formation in an animal model. METHODS: Peritoneal adhesion formation was induced by the creation of ischaemic buttons within the peritoneal wall and the formation of a colonic anastomosis in wild-type, interleukin (IL) 10-deficient (IL-10(-/-) ), IL-4-deficient (IL-4(-/-) ) and CD11b-Cre/PPARγ(fl) (/fl) mice. Adhesions were assessed at regular intervals, and cell preparations were isolated from ischaemic buttons and normal peritoneum. These samples were analysed for macrophage differentiation and its markers, and expression of cytokines by quantitative PCR, fluorescence microscopy, arginase activity and pathological examination. Some animals underwent pioglitazone (PPAR-γ agonist) or vehicle treatment to inhibit adhesion formation. Anastomotic healing was evaluated by bursting pressure measurement and collagen gene expression. RESULTS: Macrophage M2 marker expression and arginase activity were raised in buttons without adhesions compared with buttons with adhesions. IL-4(-/-) and IL-10(-/-) mice were not affected, whereas CD11b-Cre/PPARγ(fl) (/fl) mice showed decreased arginase activity and increased adhesion formation. Perioperative pioglitazone treatment increased arginase activity and decreased adhesion formation in wild-type but not CD11b-Cre/PPARγ(fl) (/fl) mice. Pioglitazone had no effect on anastomotic healing. CONCLUSION: Endogenous macrophage-specific PPAR-γ signalling affected arginase activity and macrophage polarization, and counter-regulated peritoneal adhesion manifestation. Pharmacological PPAR-γ agonism induced a shift towards macrophage M2 polarization and ameliorated adhesion formation in a macrophage-dependent manner. Surgical relevance Postoperative adhesion formation is frequently seen after abdominal surgery and occurs in response to peritoneal trauma. The pathogenesis is still unknown but includes an imbalance in fibrinolysis, collagen production and inflammatory mechanisms. Little is known about the role of macrophages during adhesion formation. In an experimental model, macrophage M2 marker expression was associated with reduced peritoneal adhesion formation and involved PPAR-γ-mediated arginase activity. Macrophage-specific PPAR-γ deficiency resulted in reduced arginase activity and aggravated adhesion formation. Pioglitazone, a PPAR-γ agonist, induced M2 polarization and reduced postoperative adhesion formation without compromising anastomotic healing in mice. Pioglitazone ameliorated postoperative adhesion formation without compromising intestinal wound healing. Therefore, perioperative PPAR-γ agonism might be a promising strategy for prevention of adhesion formation after abdominal surgery.
Assuntos
Regulação da Expressão Gênica , Macrófagos Peritoneais/metabolismo , PPAR gama/genética , Doenças Peritoneais/genética , RNA/genética , Animais , Células Cultivadas , Modelos Animais de Doenças , Laparotomia/efeitos adversos , Macrófagos Peritoneais/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , PPAR gama/biossíntese , Doenças Peritoneais/etiologia , Doenças Peritoneais/metabolismo , Reação em Cadeia da Polimerase , Transdução de Sinais , Aderências Teciduais/genética , Aderências Teciduais/metabolismo , Aderências Teciduais/patologiaRESUMO
BACKGROUND AND PURPOSE: Previous studies have indicated clinical benefits of a combination of cholinesterase inhibitors (ChEI) and memantine over ChEI monotherapy in Alzheimer's disease (AD). Our objective was the development of guidelines on the question of whether combined ChEI/memantine treatment rather than ChEI alone should be used in patients with moderate to severe AD to improve global clinical impression (GCI), cognition, behaviour and activities of daily living (ADL). METHODS: A systematic review and meta-analysis of randomized controlled trials based on a literature search in ALOIS, the register of the Cochrane Dementia and Cognitive Improvement Group, was carried out with subsequent guideline development according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. RESULTS: Pooled data from four trials including 1549 AD patients in the moderate to severe disease stage demonstrated significant beneficial effects of combination therapy compared to ChEI monotherapy for GCI [standardized mean difference (SMD) -0.20; 95% confidence interval (CI) -0.31; -0.09], cognitive functioning (SMD -0.27, 95% CI -0.37; -0.17) and behaviour (SMD -0.19; 95% CI -0.31; -0.07). The quality of evidence was high for behaviour, moderate for cognitive function and GCI and low for ADL. Agreement of panellists was reached after the second round of the consensus finding procedure. The desirable effects of combined ChEI and memantine treatment were considered to outweigh undesirable effects. The evidence was weak for cognition, GCI and ADL so that the general recommendation for using combination therapy was weak. CONCLUSIONS: We suggest the use of a combination of ChEI plus memantine rather than ChEI alone in patients with moderate to severe AD. The strength of this recommendation is weak.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Inibidores da Colinesterase/uso terapêutico , Quimioterapia Combinada , Antagonistas de Aminoácidos Excitatórios/uso terapêutico , Memantina/uso terapêutico , Guias de Prática Clínica como Assunto , HumanosRESUMO
BACKGROUND AND PURPOSE: Hippocampal atrophy is presumably one morphological sign of critical illness encephalopathy; however, predictors have not yet been determined. METHODS: The data for this report derived from patients treated at the intensive care units (ICUs) of the University Hospital in Bonn in the years 2004-2006. These patients underwent structural magnetic resonance imaging 6-24 months after discharge. Volumes (intracranial, whole brain, white matter, grey matter, cerebral spinal fluid, bilateral hippocampus) were compared with healthy controls. Pro-inflammatory parameters and ICU scoring systems were explored in conjunction with brain volumes. Cut-scores were defined to differentiate patients with high from those with low inflammatory response. RESULTS: Hippocampal and white matter volume were reduced in critically ill patients compared with healthy controls. Procalcitonin showed a very strong correlation (r = -0.903, P = 0.01) and interleukin-6 a moderate correlation (r = -0.538, P = 0.031) with hippocampal volume, but not with other brain volumes. C-reactive protein was linked to grey matter volume. There was no correlation with systemic inflammatory response syndrome criteria (body temperature, heart rate, respiratory rate, white blood cell count) or for hippocampal or whole brain volume. Furthermore, parameters representing severity of disease (APACHE II score, SOFA score, duration of stay and duration of mechanical ventilation) were not associated with hippocampal or other brain volumes. CONCLUSIONS: This analysis suggests that high levels of procalcitonin and interleukin-6 in the blood serum of critically ill patients are associated with a high likelihood of hippocampal atrophy irrespective of the severity of disease measured by ICU scoring systems and other inflammatory parameters.
Assuntos
Encefalopatias/sangue , Encefalopatias/patologia , Hipocampo/patologia , Adulto , Idoso , Atrofia/patologia , Estado Terminal , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Substância Branca/patologia , Adulto JovemRESUMO
Alzheimer's disease (AD) is the most common form of neurodegenerative dementias worldwide. Amyloid-ß deposition, neurofibrillary tangle formation and Neuroinflammation are the major pathogenetic mechanisms that in concert lead to memory dysfunction and decline of cognition. To date, there is no curative treatment for AD. Epidemiological analysis support the notion that sustained intake of non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk and delay the onset of AD. In contrast, therapeutic studies testing NSAID efficacy in AD patients have not yielded positive results. This suggests that either the investigated drugs have not addressed the mechanism of action required for mediating beneficial effects or that NSAIDs are effective at stages way before clinical onset of symptoms. The NSAIDs concerned are pleiotrophic in nature and interact with more than one pathomechanism. Therefore evidence for more than one neuroprotective action of NSAIDs has been put forward and it seems likely that some of the drugs act at multiple levels through more than one molecular mechanism. Some, even may not only be beneficial, but negative actions may be overruled by protective effects. Within these mechanisms, modulation of γ-secretase activity, the activation of the peroxisome proliferator-activated receptor-γ, binding to prostaglandin receptors or interactions at the blood-brain barrier may account for the observed protection from AD. This article reviews the current knowledge and views on the above mechanisms and critically discusses current obstacles and the potential as future AD therapeutics.
Assuntos
Doença de Alzheimer/metabolismo , Anti-Inflamatórios não Esteroides/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Barreira Hematoencefálica/metabolismo , Humanos , PPAR gama/metabolismoRESUMO
Degeneration of locus ceruleus (LC) neurons and subsequent reduction of norepinephrine (NE) in LC projection areas represent an early pathological indicator of Alzheimer's disease (AD). In order to study the effects of NE depletion on cortical and hippocampal adrenergic system changes, LC degeneration was induced in 3-month-old APP/PS1 mice by the neurotoxin N-(2-chloroethyl)-N-ethyl-bromo-benzylamine (dsp4). Dsp4 induced a widespread loss of norepinephrine transporter binding in multiple brain structures already at 4.5 months. This was accompanied by changes of α-1-, α-2-, and ß-1-adreneroceptor binding sites as well as altered adrenoceptor mRNA expression. In parallel, we observed increased micro- and astrogliosis in cortical and hippocampal structures in dsp4-treated groups. In addition, the expression of the pro-inflammatory cytokines CCL2 and IL-1ß were induced in both, dsp4-treated and APP/PS1-transgenic mice, whereas IL-1α was only up-regulated in dsp4-treated APP/PS1 mice. Concerning amyloid ß (Aß) deposition, we observed an elevation of Aß1-42 levels in aged dsp4-treated APP/PS1 mice. These data support the hypothesis that LC degeneration leads to dysregulation of adrenergic receptors and exacerbation of Aß-induced neuroinflammation, both of which are exploitable for early disease marker development.
Assuntos
Encéfalo/patologia , Locus Cerúleo/patologia , Receptores Adrenérgicos/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Animais , Autorradiografia , Encéfalo/metabolismo , Quimiocinas/biossíntese , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Gliose/patologia , Humanos , Imuno-Histoquímica , Inflamação/metabolismo , Inflamação/patologia , Locus Cerúleo/metabolismo , Camundongos , Camundongos Transgênicos , Degeneração Neural , Norepinefrina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/metabolismo , Presenilina-1/genética , RNA Mensageiro/análiseRESUMO
The current therapy of Alzheimer's disease is primarily symptomatic. Drugs which aim to modify the course of the disease are currently being developed and tested in clinical trials. Given the complex and partly unknown pathogenesis of the disease, failure of such forms of therapy has to be taken into account. Clinical epidemiology suggests a possible neuroprotective effect of statins and non-steroidal anti-inflammatory drugs, however, the molecular basis of these effects has to be further unraveled. Therapies that modify the course of Alzheimer's disease are only likely to be effective years if not decades before the disease becomes clinically apparent. Thus, the therapy of risk factors including arterial hypertension and obesity in midlife as well as a Mediterranean diet currently provides the highest chance of modifying the course of the disease.
Assuntos
Doença de Alzheimer/complicações , Doença de Alzheimer/terapia , Anti-Inflamatórios não Esteroides/uso terapêutico , Demência/complicações , Demência/terapia , Fármacos Neuroprotetores/uso terapêutico , Dieta Mediterrânea , Humanos , Resultado do TratamentoRESUMO
INTRODUCTION: Molecular imaging aims towards the non-invasive characterization of disease-specific molecular alterations in the living organism in vivo. In that, molecular imaging opens a new dimension in our understanding of disease pathogenesis, as it allows the non-invasive determination of the dynamics of changes on the molecular level. IMAGING OF AD CHARACTERISTIC CHANGES BY microPET: The imaging technology being employed includes magnetic resonance imaging (MRI) and nuclear imaging as well as optical-based imaging technologies. These imaging modalities are employed together or alone for disease phenotyping, development of imaging-guided therapeutic strategies and in basic and translational research. In this study, we review recent investigations employing positron emission tomography and MRI for phenotyping mouse models of Alzheimer's disease by imaging. We demonstrate that imaging has an important role in the characterization of mouse models of neurodegenerative diseases.
Assuntos
Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/metabolismo , Modelos Animais de Doenças , Técnicas de Sonda Molecular , Norepinefrina/metabolismo , Placa Amiloide/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Humanos , Camundongos , Compostos Radiofarmacêuticos/farmacocinéticaRESUMO
Over the past decade imaging technologies employed in clinical neurosciences have significantly advanced. Imaging is not only used for the diagnostic work-up of neurological disorders but also crucial to follow up on therapeutic efforts. Using disease-specific imaging parameters, as read-outs for the efficiency of individual therapies, has facilitated the development of various novel treatments for neurological disease. Here, we review various imaging technologies, such as cranial computed tomography (CT), magnetic resonance imaging (MRI) and spectroscopy (MRS), positron emission tomography (PET) and single-photon emission computed tomography (SPECT), with respect to their current applications in non-invasive disease phenotyping and the measurement of therapeutic outcomes in neurology. In particular, applications in neuro-oncology, Parkinson's disease, Alzheimer's disease, and cerebral ischemia are discussed. Non-invasive imaging provides further insights into the molecular pathophysiology of human diseases and facilitates the design and implementation of improved therapies.
Assuntos
Doenças do Sistema Nervoso Central/diagnóstico , Doenças do Sistema Nervoso Central/terapia , Diagnóstico por Imagem/tendências , Desenho de Fármacos , Técnicas de Sonda Molecular/tendências , Compostos Radiofarmacêuticos/uso terapêutico , Animais , Sistemas de Liberação de Medicamentos/tendências , Previsões , Humanos , Medicina Nuclear/tendênciasRESUMO
We investigated the variability in infectivity of cells in primary brain tumor samples from different patients using an HSV-1 amplicon vector. We studied the infectivity of HSV-1 amplicon vectors in tumor samples derived from neurosurgical resections of 20 patients. Cells were infected with a definite amount of HSV-1 amplicon vector HSV-GFP. Transduction efficiency in primary tumor cell cultures was compared to an established human glioma line. Moreover, duration of transgene expression was monitored in different tumor cell types. All primary cell cultures were infectable with HSV-GFP with variable transduction efficiencies ranging between 3.0 and 42.4% from reference human Gli36 Delta EGFR glioma cells. Transduction efficiency was significantly greater in anaplastic gliomas and meningiomas (26.7+/-17.4%) compared to more malignant tumor types (glioblastomas, metastases; 11.2+/-8.5%; P=0.05). To further investigate the possible underlying mechanism of this variability, nectin-1/HevC expression was analyzed and was found to contribute, at least in part, to this variability in infectability. The tumor cells expressed the exogenous gene for 7 to 61 days with significant shorter expression in glioblastomas (18+/-13 d) compared to anaplastic gliomas (42+/-24 d; P<0.05). Interindividual variability of infectivity by HSV-1 virions might explain, at least in part, why some patients enrolled in gene therapy for glioblastoma in the past exhibited a sustained response to HSV-1-based gene- and virus therapy. Infectivity of primary tumor samples from respective patients should be tested to enable the development of efficient and safe herpes vector-based gene and virus therapy for clinical application.
Assuntos
Neoplasias Encefálicas/virologia , Vetores Genéticos , Herpesvirus Humano 1/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Moléculas de Adesão Celular/metabolismo , Proliferação de Células , Expressão Gênica , Herpesvirus Humano 1/patogenicidade , Humanos , Nectinas , Proteínas de Neoplasias/metabolismo , Receptores Virais/metabolismo , Fatores de Tempo , Transdução Genética , Células Tumorais CultivadasRESUMO
We examined the effect of pioglitazone, a peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist of the thiazolidinedione class, on dopaminergic nerve cell death and glial activation in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. The acute intoxication of C57BL/6 mice with MPTP led to nigrostriatal injury, as determined by tyrosine hydroxylase (TH) immunocytochemistry, and HPLC detection of striatal dopamine and metabolites. Damage to the nigrostriatal dopamine system was accompanied by a transient activation of microglia, as determined by macrophage antigen-1 (Mac-1) and inducible nitric oxide synthase (iNOS) immunoreactivity, and a prolonged astrocytic response. Orally administered pioglitazone (approximately 20 mg/kg/day) attenuated the MPTP-induced glial activation and prevented the dopaminergic cell loss in the substantia nigra pars compacta (SNpc). In contrast, there was little reduction of MPTP-induced dopamine depletion, with no detectable effect on loss of TH immunoreactivity and glial response in the striatum of pioglitazone-treated animals. Low levels of PPARgamma expression were detected in the ventral mesencephalon and striatum, and were unaffected by MPTP or pioglitazone treatment. Since pioglitazone affects primarily the SNpc in our model, different PPARgamma-independent mechanisms may regulate glial activation in the dopaminergic terminals compared with the dopaminergic cell bodies after acute MPTP intoxication.
Assuntos
Transtornos Parkinsonianos/prevenção & controle , Receptores Citoplasmáticos e Nucleares/agonistas , Tiazóis/farmacologia , Tiazolidinedionas , Fatores de Transcrição/agonistas , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Administração Oral , Animais , Contagem de Células , Sobrevivência Celular/efeitos dos fármacos , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Modelos Animais de Doenças , Dopamina/metabolismo , Ácido Homovanílico/metabolismo , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/farmacologia , Imuno-Histoquímica , Antígeno de Macrófago 1/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neuroglia/efeitos dos fármacos , Neuroglia/patologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/patologia , Pioglitazona , Receptores Citoplasmáticos e Nucleares/biossíntese , Substância Negra/efeitos dos fármacos , Substância Negra/metabolismo , Substância Negra/patologia , Tiazóis/administração & dosagem , Fatores de Transcrição/biossíntese , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
The enzyme argininosuccinate synthetase (ASS) is the rate limiting enzyme in the metabolic pathway leading from L-citrulline to L-arginine, the physiological substrate of all isoforms of nitric oxide synthases (NOS). ASS and inducible NOS (iNOS) expression in neurons and glia was investigated by immunohistochemistry in brains of Alzheimer disease (AD) patients and nondemented, age-matched controls. In 3 areas examined (hippocampus, frontal, and entorhinal cortex), a marked increase in neuronal ASS and iNOS expression was observed in AD brains. GFAP-positive astrocytes expressing ASS were not increased in AD brains versus controls, whereas the number of iNOS expressing GFAP-positive astrocytes was significantly higher in AD brains. Density measurements revealed that ASS expression levels were significantly higher in glial cells of AD brains. Colocalization of ASS and iNOS immunoreactivity was detectable in neurons and glia. Occasionally, both ASS-and iNOS expression was detectable in CD 68-positive activated microglia cells in close proximity to senile plaques. These results suggest that neurons and astrocytes express ASS in human brain constitutively, whereas neuronal and glial ASS expression increases parallel to iNOS expression in AD. Because an adequate supply of L-arginine is indispensable for prolonged NO generation, coinduction of ASS enables cells to sustain NO generation during AD by replenishing necessary supply of L-arginine.
Assuntos
Doença de Alzheimer/metabolismo , Argininossuccinato Sintase/metabolismo , Neuroglia/enzimologia , Neurônios/enzimologia , Óxido Nítrico Sintase/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/análise , Antígenos CD/análise , Antígenos de Diferenciação Mielomonocítica/análise , Arginina/metabolismo , Argininossuccinato Sintase/análise , Citrulina/metabolismo , Encefalite/metabolismo , Encefalite/patologia , Córtex Entorrinal/enzimologia , Córtex Entorrinal/patologia , Lobo Frontal/enzimologia , Lobo Frontal/patologia , Proteína Glial Fibrilar Ácida/análise , Hipocampo/enzimologia , Hipocampo/patologia , Humanos , Neuroglia/química , Neuroglia/patologia , Neurônios/química , Neurônios/patologia , Óxido Nítrico Sintase/análise , Óxido Nítrico Sintase Tipo II , Fragmentos de Peptídeos/análiseRESUMO
The stress response (SR) can block inflammatory gene expression by preventing activation of transcription factor nuclear factor-kappa B (NF-kappaB). As inflammatory gene expression contributes to the pathogenesis of demyelinating diseases, we tested the effects of the SR on the progression of the demyelinating disease experimental autoimmune encephalomyelitis (EAE). EAE was actively induced in C57BL/6 mice using an encephalitogenic myelin oligodendrocyte glycoprotein (MOG(35-55)) peptide. Whole body hyperthermia was used to induce a heat shock response (HSR) in immunized mice 2 days after the booster MOG(35-55) peptide injection. The HSR reduced the incidence of EAE by 70%, delayed disease onset by 6 days, and attenuated disease severity. The HSR attenuated leukocyte infiltration into CNS assessed by quantitation of perivascular infiltrates, and by reduced staining for CD4 and CD25 immunopositive T-cells. T-cell activation, assessed by the production of interferon gamma (IFNgamma) in response to MOG(35-55), was also decreased by the HSR. The HSR reduced inflammatory gene expression in the brain that normally occurs during EAE, including the early increase in RANTES (regulated on activation of normal T-cell expressed and secreted) expression, and the later expression of the inducible form of nitric oxide synthase. The early activation of transcription factor NF-kappaB was also blocked by the HSR. The finding that the SR reduces inflammation in the brain and the clinical severity of EAE opens a novel therapeutic approach for prevention of autoimmune diseases.
Assuntos
Doenças Autoimunes/prevenção & controle , Encefalomielite Autoimune Experimental/prevenção & controle , Hipertermia Induzida , Glicoproteína Associada a Mielina/imunologia , Estresse Fisiológico/imunologia , Animais , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Quimiocina CCL5/biossíntese , Quimiocina CCL5/genética , Quimiotaxia de Leucócito , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Feminino , Regulação da Expressão Gênica , Imunização , Inflamação , Interferon gama/biossíntese , Interferon gama/genética , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Proteínas da Mielina , Glicoproteína Associada a Mielina/toxicidade , Glicoproteína Mielina-Oligodendrócito , NF-kappa B/fisiologia , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/biossíntese , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/toxicidade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estresse Fisiológico/genética , Subpopulações de Linfócitos T/imunologiaRESUMO
Enzymatically derived nitric oxide (NO) has been implicated in numerous physiological and pathological processes in the brain. Whereas during development NO participates in developmental and maturation processes, excess NO production in the adult in response to inflammation, injury, or trauma participates in both cell death and repair. The expression and activity of the inducible isoform of NO synthase (iNOS) play a pivotal role in sustained and elevated NO release. Recent evidence suggests that neurons can respond to proinflammatory stimuli and take part in brain inflammation. Neuronal iNOS expression has been described in different experimental settings, including cytokine stimulation of neuronal cell lines and primary neurons in vitro as well as in animal models of stroke and neurodegeneration. This article outlines different conditions leading to iNOS gene transcription and expression in neurons and neuronal cells and highlights the potential impact on human brain inflammation and neurodegeneration.
Assuntos
Neurônios/enzimologia , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase/metabolismo , Doença de Alzheimer/metabolismo , Animais , Humanos , Óxido Nítrico Sintase Tipo IIRESUMO
The role of inflammatory processes in the brains of Alzheimer's Disease (AD) patients has recently attracted considerable interest. Indeed, the only demonstrated effective therapy for AD patients is long-term treatment with non-steroidal anti-inflammatory drugs (NSAIDs). The mechanistic basis of the efficacy of NSAIDs in AD remains unclear. However, the recent recognition that NSAIDs can bind to and activate the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma), has offered an explanation for the action of these drugs in AD. PPARgamma activation leads to the inhibition of microglial activation and the expression of a broad range of proinflammatory molecules. The newly appreciated anti-inflammatory actions of PPARgamma agonists may allow novel therapies for AD and other CNS indications with an inflammatory component.
Assuntos
Doença de Alzheimer/patologia , Doença de Alzheimer/prevenção & controle , Anti-Inflamatórios não Esteroides/farmacologia , Inflamação/prevenção & controle , Receptores Citoplasmáticos e Nucleares/agonistas , Fatores de Transcrição/agonistas , Animais , Humanos , Receptores Citoplasmáticos e Nucleares/biossíntese , Receptores Citoplasmáticos e Nucleares/fisiologia , Fatores de Transcrição/biossíntese , Fatores de Transcrição/fisiologiaRESUMO
Expression of the inducible form of nitric oxide synthase (iNOS) in brain may contribute to neurotoxicity in Alzheimer's disease (AD). Expression of iNOS can be induced in cerebellar granule cells (CGCs) in vivo as well as in vitro, allowing these cells to be used to study regulation of neuronal iNOS expression. We report here that microinjection of bacterial lipopolysaccharide and interferon gamma into rat cerebellum induced iNOS expression in CGCs and subsequent cell death assessed by staining for DNA fragmentation. Co-injection of three structurally distinct agonists of the peroxisome proliferator-activated receptor gamma (PPARgamma), including the antidiabetic thiazolidinedione troglitazone, the nonsteroidal anti-inflammatory drug (NSAID) ibuprofen, and the prostanoid 15-deoxy-Delta(12,14) prostaglandin J(2), reduced both iNOS expression and cell death, whereas co-injection of the selective cyclo-oxygenase inhibitor NS-398 had no effect. These data demonstrate that PPARgamma agonists can modulate inflammatory responses in brain. Because sustained medication with NSAIDs reduces the risk and delays the onset of AD, these results further suggest that NSAIDs provide therapeutic value by binding to PPARgamma present in AD brain, thereby preventing iNOS expression and neuronal cell death.
Assuntos
Morte Celular , Óxido Nítrico Sintase/biossíntese , Prostaglandina D2/análogos & derivados , Receptores Citoplasmáticos e Nucleares/metabolismo , Tiazolidinedionas , Fatores de Transcrição/metabolismo , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/metabolismo , Morte Celular/efeitos dos fármacos , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Cromanos/administração & dosagem , Cromanos/metabolismo , Inibidores de Ciclo-Oxigenase/administração & dosagem , Inibidores de Ciclo-Oxigenase/metabolismo , Regulação para Baixo/efeitos dos fármacos , Ibuprofeno/administração & dosagem , Ibuprofeno/metabolismo , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Interferon gama/administração & dosagem , Ligantes , Lipopolissacarídeos/administração & dosagem , Masculino , Microinjeções , Óxido Nítrico Sintase Tipo II , Nitrobenzenos/administração & dosagem , Prostaglandina D2/administração & dosagem , Prostaglandina D2/metabolismo , Ratos , Ratos Sprague-Dawley , Sulfonamidas/administração & dosagem , Tiazóis/administração & dosagem , Tiazóis/metabolismo , TroglitazonaRESUMO
The heat shock response (HSR) provides protection against stress-induced damage, and also prevents initiation of inflammatory gene expression via inhibition of NFkappaB activation. This article describes experiments demonstrating that the HSR prevents induction of nitric oxide synthase type 2 (NOS2) in rat brain. Twenty four hours after intrastriatal injection of lipopolysaccharide (LPS), IL-1beta, and IFN-gamma, NOS2 immunoreactive cells were detected in striatum, corpus callosum, and to a lesser extent in cortex. Induction of a HSR by whole body warming to 41 degrees C for 20 minutes, done 1 day before LPS plus cytokine injection, reduced the number of NOS2-positive staining cells to background levels. Staining for EDI antigen revealed that the HSR also suppressed microglial/brain macrophage activation in the same areas. Striatal injection of LPS and cytokines induced the rapid activation of NFkappaB, and this activation was prevented by prior HS, which also increased brain IkappaB-alpha expression. These results suggest that establishment of a HSR can reduce inflammatory gene expression in brain, mediated by inhibition of NFkappaB activation, and may therefore offer a novel approach to treatment and prevention of neurological disease and trauma.
Assuntos
Encéfalo/fisiologia , Resposta ao Choque Térmico/fisiologia , Macrófagos/efeitos dos fármacos , Microglia/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , Óxido Nítrico Sintase/antagonistas & inibidores , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Feminino , Macrófagos/fisiologia , Microglia/fisiologia , Óxido Nítrico Sintase Tipo II , Ratos , Ratos Sprague-DawleyRESUMO
Here we study expression of the inducible isoform of nitric oxide synthases after intrastriatal microinjection of interferon-gamma and bacterial lipopolysaccharide in the rat at different time points to detect time- and localisation-dependent changes of iNOS expression. Three different areas in the striatum and the corpus callosum were evaluated. Antibodies against the glial fibrillary acidic protein and the microglia/brain macrophage epitope ED1 were used to detect colocalization of inducible nitric oxide synthase with astrocytes or activated microglia/brain macrophages, respectively. Inducible nitric oxide synthase-positive cells occurred first in intravascular and perivascular cells at 4 h. Perivascular and parenchymal inducible nitric oxide synthase expression increased up to 24 h in the striatum, whereas in the corpus callosum inducible nitric oxide synthase expression was maximal after 16 h. Inducible nitric oxide synthase was still present in perivascular cells 7 days after immunostimulation. At all time points, inducible nitric oxide synthase was predominantly detected in ED1-positive microglia/brain. Nitrotyrosine immunohistochemistry was performed to detect NO-mediated nitration of proteins at all time points. Nitrotyrosine-positive neurons and microglial cells were detected from 24 h until 7 days after immunostimulation and were absent in controls. Detailed knowledge of the changes in the time course and cellular source of inducible nitric oxide synthase expression following brain immunostimulation provide a basis for establishing treatment strategies and windows of therapeutic intervention during neuroinflammation.
Assuntos
Antineoplásicos/farmacologia , Astrócitos/enzimologia , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Óxido Nítrico Sintase/metabolismo , Animais , Astrócitos/química , Astrócitos/efeitos dos fármacos , Corpo Caloso/citologia , Corpo Estriado/citologia , Proteína Glial Fibrilar Ácida/análise , Marcação In Situ das Extremidades Cortadas , Masculino , Microglia/química , Microglia/efeitos dos fármacos , Microglia/enzimologia , Microinjeções , Neurite (Inflamação)/enzimologia , Óxido Nítrico Sintase Tipo II , Ratos , Ratos Wistar , Tirosina/análogos & derivados , Tirosina/análiseRESUMO
The enzyme argininosuccinate synthetase (ASS) initiates the metabolic pathway leading from L-citrulline to L-arginine, the only physiological substrate of all isoforms of nitric oxide synthases. The presence of ASS in glial cells in vivo was investigated by immunohistochemical methods in a model of rat brain inflammation. Phosphate-buffered saline or a mixture of bacterial lipopolysaccharide and interferon-gamma was injected into the left striatum, and animals were killed 24 hours later. Ipsilateral and contralateral sides of brain sections were incubated with an antiserum against ASS or antibodies against cell-specific markers. In the three areas examined, striatum, corpus callosum, and cortex, a strong induction of ASS immunoreactivity was observed in glial cells after injection of immunostimulants. A detailed quantitative analysis of double-stained sections revealed that ASS was almost exclusively expressed in reactive, ED1-positive microglial cells/brain macrophages in immunostimulant- or sham-injected ipsilateral sides of the sections. Furthermore, ASS/ED1 costaining was observed in perivascular cells. Colocalization of ASS with astroglial marker glial fibrillary acidic protein was given only occasionally after immunostimulation. ASS-positive neurons were detected in control and experimental animals; staining intensity was comparable in both cases. The results suggest that neurons express ASS constitutively, whereas the enzyme is induced in glial cells in response to proinflammatory stimuli. This finding is the first demonstration of an induction of a pathway auxiliary to generation of nitric oxide in brain in response to immunostimulants and provides new insight into neural arginine metabolism.