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Oliveira GB, Fontes EDA, de Carvalho S, da Silva JB, Fernandes LMP, Oliveira MCSP, Prediger RD, Gomes-Leal W, Lima RR, Maia CSF. Minocycline mitigates motor impairments and cortical neuronal loss induced by focal ischemia in rats chronically exposed to ethanol during adolescence. Brain Res 2014; 1561:23-34. [PMID: 24637259 DOI: 10.1016/j.brainres.2014.03.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 01/29/2014] [Accepted: 03/07/2014] [Indexed: 12/12/2022]
Abstract
Ethanol is an important risk factor for the occurrence of cerebral ischemia contributing to poor prognosis and inefficacy of drug treatments for stroke-related symptoms. Females have a higher lifetime risk for stroke than males. Moreover, female gender has been associated with increased ethanol consumption during adolescence. In the present study, we investigated whether chronic ethanol exposure during adolescence may potentiate the motor impairments and cortical damage induced by focal ischemia in female rats. We also addressed whether these effects can be mitigated by minocycline, which has been shown to be neuroprotective against different insults in the CNS. Female rats were treated with distilled water or ethanol (6.5 g/kg/day, 22.5% w/v) for 55 days by gavage. Focal ischemia was induced by microinjections of endothelin-1 (ET-1) into the motor cortex. Animals of both groups were treated daily with minocycline (25-50 mg/kg, i.p.) or sterile saline (i.p.) for 5 days, and motor function was assessed using open field, inclined plane and rotarod tests. Chronic ethanol exposure exacerbated locomotor activity and motor coordination impairments induced by focal ischemia in rats. Moreover, histological analysis revealed that microinjections of ET-1 induced pyramidal neuron loss and microglial activation in the motor cortex. Minocycline reversed the observed motor impairments, microglial activation and pyramidal neuron loss in the motor cortex of ischemic rats even in those exposed to ethanol. These results suggest that minocycline induces neuroprotection and functional recovery in ischemic female rats intoxicated with ethanol during adolescence. Furthermore, the mechanism underlying this protective effect may be related to the modulation of neuroinflammation.
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Affiliation(s)
- Gedeão Batista Oliveira
- Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil
| | - Enéas de Andrade Fontes
- Programa de Pós-graduação em Neurociências e Biologia Celular, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil
| | - Sabrina de Carvalho
- Laboratório de Farmacologia da Inflamação e do Comportamento, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil
| | - Josiane Batista da Silva
- Laboratório de Farmacologia da Inflamação e do Comportamento, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil
| | - Luanna Melo Pereira Fernandes
- Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil; Laboratório de Farmacologia da Inflamação e do Comportamento, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil
| | - Maria Cristina Souza Pereira Oliveira
- Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil
| | - Rui Daniel Prediger
- Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, 88049-900 Florianópolis, SC, Brazil
| | - Walace Gomes-Leal
- Laboratório de Neuroproteção e Neurorregeneração Experimental do Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil
| | - Rafael Rodrigues Lima
- Laboratório de Neuroproteção e Neurorregeneração Experimental do Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil
| | - Cristiane Socorro Ferraz Maia
- Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil; Programa de Pós-graduação em Neurociências e Biologia Celular, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil; Laboratório de Farmacologia da Inflamação e do Comportamento, Faculdade de Farmácia, Instituto de Ciências da Saúde, Universidade Federal do Pará, 66075-900 Belém, Pará, Brazil.
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202
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A genetic variant in the microRNA-146a gene is associated with susceptibility to alcohol use disorders. Eur Psychiatry 2014; 29:288-92. [PMID: 24630744 DOI: 10.1016/j.eurpsy.2014.02.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 12/18/2013] [Accepted: 02/02/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Polymorphisms in the microRNA (miRNA) regulatory pathways are novel functional genetic variants whose association with alcoholism susceptibility has not been previously studied. Given the potential relationship between certain miRNAs and alcohol use disorders (AUDs), this study was designed to explore the association between two polymorphisms within hsa-miR-146a and hsa-miR-196a2 genes and susceptibility to these diseases. METHODS Three hundred and one male patients with AUDs and 156 sex-matched healthy volunteers were enrolled. Polymorphisms were genotyped using TaqMan(®) PCR assays. Allele and genotype frequencies were compared between groups and logistic regression analysis was also performed to analyze the model of inheritance. RESULTS There was a significantly higher prevalence of allele C carriers (47.8%) of the miR-146a G>C polymorphism (rs2910164) among patients with AUDs when compared with controls (35.9%), and multivariable logistic regression analysis showed that the C allele was associated with these AUDs (OR=1.615, 95% CI 1.067-2.442; P=0.023). Neither the genotype nor the allele distribution of miR-196a2 polymorphism (rs11614913) was significantly different between groups. CONCLUSIONS This is the first genetic association study to explore the relationship of miRNA polymorphisms with AUDs and to show an association of the miR-146a C>G rs2910164 allelic variant with this disease.
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203
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Monnig MA, Thayer RE, Caprihan A, Claus ED, Yeo RA, Calhoun VD, Hutchison KE. White matter integrity is associated with alcohol cue reactivity in heavy drinkers. Brain Behav 2014; 4:158-70. [PMID: 24683509 PMCID: PMC3967532 DOI: 10.1002/brb3.204] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 11/17/2013] [Accepted: 11/25/2013] [Indexed: 02/07/2023] Open
Abstract
Neuroimaging studies have shown that white matter damage accompanies excessive alcohol use, but the functional correlates of alcohol-related white matter disruption remain unknown. This study applied tract-based spatial statistics (TBSS) to diffusion tensor imaging (DTI) data from 332 heavy drinkers (mean age = 31.2 ± 9.4; 31% female) to obtain averaged fractional anisotropy (FA) values of 18 white matter tracts. Statistical analyses examined correlations of FA values with blood-oxygenation-level-dependent (BOLD) response to an alcohol taste cue, measured with functional magnetic resonance imaging (fMRI). FA values of nine white matter tracts (anterior corona radiata, body of corpus callosum, cingulate gyrus, external capsule, fornix, inferior frontooccipital fasciculus, posterior corona radiata, retrolenticular limb of internal capsule, and superior longitudinal fasciculus) were significantly, negatively correlated with BOLD activation in medial frontal gyrus, parahippocampal gyrus, fusiform gyrus, cingulum, thalamus, caudate, putamen, insula, and cerebellum. The inverse relation between white matter integrity and functional activation during the alcohol taste cue provides support for the hypothesis that lower white matter integrity in frontoparietal and corticolimbic networks is a factor in loss of control over alcohol consumption.
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Affiliation(s)
- Mollie A Monnig
- Mind Research Network Albuquerque, 87106, New Mexico ; University of New Mexico Albuquerque, 87106, New Mexico
| | | | | | - Eric D Claus
- Mind Research Network Albuquerque, 87106, New Mexico ; University of New Mexico Albuquerque, 87106, New Mexico
| | - Ronald A Yeo
- Mind Research Network Albuquerque, 87106, New Mexico ; University of New Mexico Albuquerque, 87106, New Mexico
| | - Vince D Calhoun
- Mind Research Network Albuquerque, 87106, New Mexico ; University of New Mexico Albuquerque, 87106, New Mexico
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204
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Pla A, Pascual M, Renau-Piqueras J, Guerri C. TLR4 mediates the impairment of ubiquitin-proteasome and autophagy-lysosome pathways induced by ethanol treatment in brain. Cell Death Dis 2014; 5:e1066. [PMID: 24556681 PMCID: PMC3944260 DOI: 10.1038/cddis.2014.46] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 12/19/2013] [Accepted: 01/20/2014] [Indexed: 12/28/2022]
Abstract
New evidence indicates the involvement of protein degradation dysfunctions in neurodegeneration, innate immunity response and alcohol hepatotoxicity. We recently demonstrated that ethanol increases brain proinflammatory mediators and causes brain damage by activating Toll-like receptor 4 (TLR4) signaling in glia. However, it is uncertain if the ubiquitin-proteasome and autophagy-lysosome pathways are involved in ethanol-induced brain damage and whether the TLR4 response is implicated in proteolytic processes. Using the cerebral cortex of WT and TLR4-knockout mice with and without chronic ethanol treatment, we demonstrate that ethanol induces poly-ubiquitinated proteins accumulation and promotes immunoproteasome activation by inducing the expression of β2i, β5i and PA28α, although it decreases the 20S constitutive proteasome subunits (α2, β5). Ethanol also upregulates mTOR phosphorylation, leading to a downregulation of the autophagy-lysosome pathway (ATG12, ATG5, cathepsin B, p62, LC3) and alters the volume of autophagic vacuoles. Notably, mice lacking TLR4 receptors are protected against ethanol-induced alterations in protein degradation pathways. In summary, the present results provide the first evidence demonstrating that chronic ethanol treatment causes proteolysis dysfunctions in the mouse cerebral cortex and that these events are TLR4 dependent. These findings could provide insight into the mechanisms underlying ethanol-induced brain damage.
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Affiliation(s)
- A Pla
- Department of Cellular Pathology, Centro de Investigación Príncipe Felipe, C/Eduardo Primo Yúfera 3, Valencia 46012, Spain
| | - M Pascual
- Department of Cellular Pathology, Centro de Investigación Príncipe Felipe, C/Eduardo Primo Yúfera 3, Valencia 46012, Spain
| | - J Renau-Piqueras
- Section of Biology and Cellular Pathology, Centro Investigación Hospital La Fe, Avda. de Campanar 114, Valencia 46015, Spain
| | - C Guerri
- Department of Cellular Pathology, Centro de Investigación Príncipe Felipe, C/Eduardo Primo Yúfera 3, Valencia 46012, Spain
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205
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Release of neuronal HMGB1 by ethanol through decreased HDAC activity activates brain neuroimmune signaling. PLoS One 2014. [PMID: 24551070 DOI: 10.1371/journal.pone.0087915.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuroimmune gene induction is involved in many brain pathologies including addiction. Although increased expression of proinflammatory cytokines has been found in ethanol-treated mouse brain and rat brain slice cultures as well as in post-mortem human alcoholic brain, the mechanisms remain elusive. High-mobility group box 1 (HMGB1) protein is a nuclear protein that has endogenous cytokine-like activity. We previously found increased HMGB1 in post-mortem alcoholic human brain as well as in ethanol treated mice and rat brain slice cultures. The present study investigated the mechanisms for ethanol-induced release of HMGB1 and neuroimmune activation in a model of rat hippocampal-entorhinal cortex (HEC) brain slice cultures. Ethanol exposure triggered dose-dependent HMGB1 release, predominantly from neuronal cells. Inhibitors of histone deacetylases (HDACs) promoted nucleocytoplasmic mobilization of HDAC1/4 and HMGB1 resulting in increased total HMGB1 and acetylated HMGB1 release. Similarly, ethanol treatment was found to induce the translocation of HDAC1/4 and HMGB1 proteins from nuclear to cytosolic fractions. Furthermore, ethanol treatment reduced HDAC1/4 mRNA and increased acetylated HMGB1 release into the media. These results suggest decreased HDAC activity may be critical in regulating acetylated HMGB1 release from neurons in response to ethanol. Ethanol and HMGB1 treatment increased mRNA expression of proinflammatory cytokines TNFα and IL-1β as well as toll-like receptor 4 (TLR4). Targeting HMGB1 or microglial TLR4 by using siRNAs to HMGB1 and TLR4, HMGB1 neutralizing antibody, HMGB1 inhibitor glycyrrhizin and TLR4 antagonist as well as inhibitor of microglial activation all blocked ethanol-induced expression of proinflammatory cytokines TNFα and IL-1β. These results support the hypothesis that ethanol alters HDACs that regulate HMGB1 release and that danger signal HMGB1 as endogenous ligand for TLR4 mediates ethanol-induced brain neuroimmune signaling through activation of microglial TLR4. These findings provide new therapeutic targets for brain neuroimmune activation and alcoholism.
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206
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Zou JY, Crews FT. Release of neuronal HMGB1 by ethanol through decreased HDAC activity activates brain neuroimmune signaling. PLoS One 2014; 9:e87915. [PMID: 24551070 PMCID: PMC3925099 DOI: 10.1371/journal.pone.0087915] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 12/31/2013] [Indexed: 12/11/2022] Open
Abstract
Neuroimmune gene induction is involved in many brain pathologies including addiction. Although increased expression of proinflammatory cytokines has been found in ethanol-treated mouse brain and rat brain slice cultures as well as in post-mortem human alcoholic brain, the mechanisms remain elusive. High-mobility group box 1 (HMGB1) protein is a nuclear protein that has endogenous cytokine-like activity. We previously found increased HMGB1 in post-mortem alcoholic human brain as well as in ethanol treated mice and rat brain slice cultures. The present study investigated the mechanisms for ethanol-induced release of HMGB1 and neuroimmune activation in a model of rat hippocampal-entorhinal cortex (HEC) brain slice cultures. Ethanol exposure triggered dose-dependent HMGB1 release, predominantly from neuronal cells. Inhibitors of histone deacetylases (HDACs) promoted nucleocytoplasmic mobilization of HDAC1/4 and HMGB1 resulting in increased total HMGB1 and acetylated HMGB1 release. Similarly, ethanol treatment was found to induce the translocation of HDAC1/4 and HMGB1 proteins from nuclear to cytosolic fractions. Furthermore, ethanol treatment reduced HDAC1/4 mRNA and increased acetylated HMGB1 release into the media. These results suggest decreased HDAC activity may be critical in regulating acetylated HMGB1 release from neurons in response to ethanol. Ethanol and HMGB1 treatment increased mRNA expression of proinflammatory cytokines TNFα and IL-1β as well as toll-like receptor 4 (TLR4). Targeting HMGB1 or microglial TLR4 by using siRNAs to HMGB1 and TLR4, HMGB1 neutralizing antibody, HMGB1 inhibitor glycyrrhizin and TLR4 antagonist as well as inhibitor of microglial activation all blocked ethanol-induced expression of proinflammatory cytokines TNFα and IL-1β. These results support the hypothesis that ethanol alters HDACs that regulate HMGB1 release and that danger signal HMGB1 as endogenous ligand for TLR4 mediates ethanol-induced brain neuroimmune signaling through activation of microglial TLR4. These findings provide new therapeutic targets for brain neuroimmune activation and alcoholism.
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Affiliation(s)
- Jian Y. Zou
- Bowles Center For Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Fulton T. Crews
- Bowles Center For Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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207
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Ward RJ, Lallemand F, de Witte P. Influence of adolescent heavy session drinking on the systemic and brain innate immune system. Alcohol Alcohol 2014; 49:193-7. [PMID: 24532587 DOI: 10.1093/alcalc/agu002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS The aim of the study was to evaluate rat models of intermittent alcohol abuse (heavy session/'heavy session' drinking) in relation to inflammatory changes in specific brain regions as well as in the periphery. Furthermore, the study was aimed to assess whether there are inflammatory changes in the blood of human intermittent alcohol abusers who might be associated with changes in neuronal circuitry in the brain, as assessed by functional magnetic resonance imaging (fMRI), which cause adverse effects on memory and learning. METHODS Various regimes of intermittent alcohol administration have been used in rat models, which vary with respect to the dose and duration of ethanol administration as well as the time of abstinence. Immunohistological methods were used to identify activated microglia in specific brain regions. The response of isolated alveolar macrophages to in vitro stimuli was assessed by the assay of nitric oxide and the pro-inflammatory cytokines IL-6 and TNFα. Blood samples were collected from university students who had been heavy session drinkers for 2 years to assess whether there was an inflammatory cytokine profile that correlated with cognitive test scores as well as fMRI findings. RESULTS The extent of microglia activation appears to depend on the doses and duration of ethanol administration. In addition, there is activation of phagocytic cells in the periphery, e.g. alveolar macrophages, in the rat models of heavy session drinking. Changes in the plasma levels of pro- and anti-inflammatory cytokines were present in heavy session drinking students, although no changes were identified in specific cognitive tests (which may be because of compensatory changes in the prefrontal cortex, as identified by fMRI). CONCLUSION Changes in the cytokine levels induced by intermittent ethanol abuse may provoke inflammatory pathways in specific brain regions, such as hippocampus and prefrontal cortex (particularly during the stage of active neurogenesis in the adolescent brain), which might induce cognitive impairment in susceptible individuals.
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Affiliation(s)
- Roberta J Ward
- Corresponding author: Biologie du Comportement, Université Catholique de Louvain, Croix du Sud, 1 - box L7.04.03, 1348 Louvain-la-Neuve, Belgium.
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208
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Mycoepoxydiene inhibits activation of BV2 microglia stimulated by lipopolysaccharide through suppressing NF-κB, ERK 1/2 and toll-like receptor pathways. Int Immunopharmacol 2014; 19:88-93. [PMID: 24447679 DOI: 10.1016/j.intimp.2014.01.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 12/08/2013] [Accepted: 01/06/2014] [Indexed: 11/24/2022]
Abstract
Mycoepoxydiene (MED) is a polyketide isolated from the marine fungal Diaporthe sp. HLY-1 associated with mangroves. Although MED has been shown to have various biological effects such as antimicrobial, anti-cancer, and anti-inflammatory activities, its activities and cellular mechanisms during microglial activation have yet to be elucidated. In the present study, we assessed the anti-inflammatory effect of MED on the production of inflammatory mediators in lipopolysaccharide (LPS)-stimulated murine BV2 microglia. MED significantly inhibited LPS-induced production of pro-inflammatory mediators such as tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), interferon-γ (INF-γ), and nitric oxide (NO), whereas it increased anti-inflammatory interleukin-10 (IL-10) and transforming growth factor-β1 (TGF-β1) production in BV2 microglia in a concentration-dependent manner without causing cytotoxicity. Moreover, MED suppressed NF-κB activation by blocking IkappaB-α (IκB-α) degradation and inhibited the phosphorylation of ERK 1/2 and toll-like receptor 4 (TLR4) expression, but had no effect on the phosphorylation of JNK, and p38. Our results demonstrate that the inhibitory and promotion effect of MED on LPS-stimulated inflammatory mediators and anti-inflammatory factor production in BV2 microglia is associated with the suppression of the NF-κB, ERK1/2 and TLR signaling pathways. Therefore, MED may have therapeutic potential for neurodegenerative diseases by inhibiting inflammatory mediators and enhancing anti-inflammatory factor production in activated microglia.
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209
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Pascual-Lucas M, Fernandez-Lizarbe S, Montesinos J, Guerri C. LPS or ethanol triggers clathrin- and rafts/caveolae-dependent endocytosis of TLR4 in cortical astrocytes. J Neurochem 2014; 129:448-62. [PMID: 24345077 DOI: 10.1111/jnc.12639] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 12/12/2013] [Accepted: 12/12/2013] [Indexed: 12/14/2022]
Abstract
Toll-like receptor 4 (TLR4) activation and signalling in glial cells play critical roles in neurological disorders and in alcohol-induced brain damage. TLR4 endocytosis upon lipopolysaccharide (LPS) stimulation regulates which signalling pathway is activated, the MyD88-dependent or the TIR-domain-containing adapter-inducing interferon-β (TRIF)-dependent pathway. However, it remains elusive whether ethanol-induced TLR4 signalling is associated with receptor internalization and trafficking, and which endocytic pathway(s) are used in cortical astrocytes. Using the adenoviral over-expression of TLR4(GFP) , confocal microscopy and the imagestream technique, we show that upon ethanol or LPS stimulation, TLR4 co-localizes with markers of the clathrin and caveolin endocytic pathways, and that this endocytosis is dependent on dynamin. Using chlorpromazin and filipin as inhibitors of the clathrin and rafts/caveolae endocytic pathways, respectively, we demostrate that TRIF-dependent signalling relies on an intact clathrin pathway, whereas disruption of rafts/caveolae inhibits the MyD88- and TRIF-dependent signalling pathways. Immunofluorescence studies also suggest that lipid rafts and clathrin cooperate for appropriate TLR4 internalization. We also show that ethanol can trigger similar endocytic pathways as LPS does, although ethanol delays clathrin internalization and alters TLR4 vesicular trafficking. Our results provide new insights into the effects of ethanol or LPS on TLR4 signalling in cortical astrocytes, events that may underlie neuroinflammation and brain damage. The results demonstrate that ethanol or lipopolysaccharide (LPS) triggers toll-like receptor 4 (TLR4) endocytosis by caveolae and clathrin-dependent pathways in astrocytes. We proposed that while clathrin is the protein responsible for TLR4 internalization, caveolin-1/lipid rafts membrane microdomains are required for TLR4 signaling. The results provide new insights into the effects of ethanol on TLR4 signalling in astrocytes, events that may underlie neuroinflammation.
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Affiliation(s)
- Maya Pascual-Lucas
- Department of Cellular Pathology, Príncipe Felipe Research Centre, Valencia, Spain
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210
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Drew PD, Kane CJM. Fetal alcohol spectrum disorders and neuroimmune changes. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 118:41-80. [PMID: 25175861 DOI: 10.1016/b978-0-12-801284-0.00003-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The behavioral consequences of fetal alcohol spectrum disorders (FASD) are serious and persist throughout life. The causative mechanisms underlying FASD are poorly understood. However, much has been learned about FASD from human structural and functional studies as well as from animal models, which have provided a greater understanding of the mechanisms underlying FASD. Using animal models of FASD, it has been recently discovered that ethanol induces neuroimmune activation in the developing brain. The resulting microglial activation, production of proinflammatory molecules, and alteration in expression of developmental genes are postulated to alter neuron survival and function and lead to long-term neuropathological and cognitive defects. It has also been discovered that microglial loss occurs, reducing microglia's ability to protect neurons and contribute to neuronal development. This is important, because emerging evidence demonstrates that microglial depletion during brain development leads to long-term neuropathological and cognitive defects. Interestingly, the behavioral consequences of microglial depletion and neuroimmune activation in the fetal brain are particularly relevant to FASD. This chapter reviews the neuropathological and behavioral abnormalities of FASD and delineates correlates in animal models. This serves as a foundation to discuss the role of the neuroimmune system in normal brain development, the consequences of microglial depletion and neuroinflammation, the evidence of ethanol induction of neuroinflammatory processes in animal models of FASD, and the development of anti-inflammatory therapies as a new strategy for prevention or treatment of FASD. Together, this knowledge provides a framework for discussion and further investigation of the role of neuroimmune processes in FASD.
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Affiliation(s)
- Paul D Drew
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Cynthia J M Kane
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
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211
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Guizzetti M, Zhang X, Goeke C, Gavin DP. Glia and neurodevelopment: focus on fetal alcohol spectrum disorders. Front Pediatr 2014; 2:123. [PMID: 25426477 PMCID: PMC4227495 DOI: 10.3389/fped.2014.00123] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 10/24/2014] [Indexed: 12/03/2022] Open
Abstract
During the last 20 years, new and exciting roles for glial cells in brain development have been described. Moreover, several recent studies implicated glial cells in the pathogenesis of neurodevelopmental disorders including Down syndrome, Fragile X syndrome, Rett Syndrome, Autism Spectrum Disorders, and Fetal Alcohol Spectrum Disorders (FASD). Abnormalities in glial cell development and proliferation and increased glial cell apoptosis contribute to the adverse effects of ethanol on the developing brain and it is becoming apparent that the effects of fetal alcohol are due, at least in part, to effects on glial cells affecting their ability to modulate neuronal development and function. The three major classes of glial cells, astrocytes, oligodendrocytes, and microglia as well as their precursors are affected by ethanol during brain development. Alterations in glial cell functions by ethanol dramatically affect neuronal development, survival, and function and ultimately impair the development of the proper brain architecture and connectivity. For instance, ethanol inhibits astrocyte-mediated neuritogenesis and oligodendrocyte development, survival and myelination; furthermore, ethanol induces microglia activation and oxidative stress leading to the exacerbation of ethanol-induced neuronal cell death. This review article describes the most significant recent findings pertaining the effects of ethanol on glial cells and their significance in the pathophysiology of FASD and other neurodevelopmental disorders.
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Affiliation(s)
- Marina Guizzetti
- Department of Psychiatry, University of Illinois at Chicago , Chicago, IL , USA ; Jesse Brown VA Medical Center, U.S. Department of Veterans Affairs , Chicago, IL , USA ; Department of Environmental and Occupational Health Sciences, University of Washington , Seattle, WA , USA
| | - Xiaolu Zhang
- Department of Psychiatry, University of Illinois at Chicago , Chicago, IL , USA ; Jesse Brown VA Medical Center, U.S. Department of Veterans Affairs , Chicago, IL , USA
| | - Calla Goeke
- Department of Psychiatry, University of Illinois at Chicago , Chicago, IL , USA ; Jesse Brown VA Medical Center, U.S. Department of Veterans Affairs , Chicago, IL , USA
| | - David P Gavin
- Department of Psychiatry, University of Illinois at Chicago , Chicago, IL , USA ; Jesse Brown VA Medical Center, U.S. Department of Veterans Affairs , Chicago, IL , USA
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212
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Szabo G, Lippai D. Converging actions of alcohol on liver and brain immune signaling. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 118:359-80. [PMID: 25175869 DOI: 10.1016/b978-0-12-801284-0.00011-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chronic excessive alcohol consumption results in inflammation in multiple organs, including the brain. While the contribution of neuroinflammation to alcohol-related cognitive dysfunction and behavioral alterations is established, the mechanisms by which alcohol triggers inflammation in the brain are only partially understood. There are acute and long-term alterations in brain function due to intercellular and intracellular changes of different cell types as a result of alcohol consumption. This review focuses on the alcohol-induced proinflammatory cellular and molecular changes in the central nervous system. Alcohol passes through the blood-brain barrier and alters neurotransmission. Alcohol use activates microglia and astrocyte, contributing to neurodegeneration and impaired regeneration. Alcohol-induced cell injury in the brain results in release of damage-associated molecular patterns, such as high mobility group box 1, that trigger inflammatory changes through activation of pattern recognition receptors. In addition, alcohol consumption increases intestinal permeability and results in increased levels of pathogen-associated molecular pattern such as endotoxin in the systemic circulation that triggers PRRs and inflammation. The Toll-like receptor-4 pathway that activates nuclear factor-κB and secretion of proinflammatory cytokines, tumor necrosis factor-α, interleukin-1-beta, and chemokines, including monocyte chemotactic protein-1, has been suggested to contribute to alcohol-induced neuroinflammation. Alcohol-induced IL-1β secretion also requires Nod-like receptor-mediated inflammasome and caspase-1 activation, and, consistent with this, disruption of IL-1/IL-1-receptor signaling prevents alcohol-induced neuroinflammation. Delicate regulators of inflammatory gene expressions are micro-RNAs (miRs) that have recently been identified in alcohol-related neuroinflammation. Alcohol induces miR155, a regulator of inflammation in the brain, and deficiency in miR-155 in mice was protective from neuroinflammatory changes. These observations suggest that manipulation of miR pathways and cytokine induction may reduce alcohol-induced proinflammatory processes.
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Affiliation(s)
- Gyongyi Szabo
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
| | - Dora Lippai
- 2nd Department of Internal Medicine, Semmelweis University, Budapest, Hungary
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Abstract
Chronic use of alcohol results in progressive changes to brain and behavior that often lead to the development of alcohol dependence and alcoholism. Although the mechanisms underlying the development of alcoholism remain to be fully elucidated, diminished executive functioning due to hypoactive prefrontal cortex executive control and hyperactive limbic system anxiety and negative emotion might contribute mechanistically to the shift from experimental use to alcoholism and dependence. In the chapter that follows, behavioral deficits associated with cortical dysfunction and neurodegeneration will be related to the behavioral characteristics of alcoholism (e.g., diminished executive function, impulsivity, altered limbic modulation). We will provide evidence that alterations in cyclic AMP-responsive element binding protein (CREB: neurotrophic) and NF-κB (neuroimmune) signaling contribute to the development and persistence of alcoholism. In addition, genetic predispositions and an earlier age of drinking onset will be discussed as contributing factors to the development of alcohol dependence and alcoholism. Overall chronic ethanol-induced neuroimmune gene induction is proposed to alter limbic and frontal neuronal networks contributing to the development and persistence of alcoholism.
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Affiliation(s)
- R P Vetreno
- Bowles Center for Alcohol Studies, Department of Pharmacology and Psychiatry, University of North Carolina, Chapel Hill, NC, USA.
| | - F T Crews
- Bowles Center for Alcohol Studies, Department of Pharmacology and Psychiatry, University of North Carolina, Chapel Hill, NC, USA
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Neuroimmune pathways in alcohol consumption: evidence from behavioral and genetic studies in rodents and humans. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 118:13-39. [PMID: 25175860 DOI: 10.1016/b978-0-12-801284-0.00002-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Immune or brain proinflammatory signaling has been linked to some of the behavioral effects of alcohol. Immune signaling appears to regulate voluntary ethanol intake in rodent models, and ethanol intake activates the immune system in multiple models. This bidirectional link raises the possibility that consumption increases immune signaling, which in turn further increases consumption in a feed-forward cycle. Data from animal and human studies provide overlapping support for the involvement of immune-related genes and proteins in alcohol action, and combining animal and human data is a promising approach to systematically evaluate and nominate relevant pathways. Based on rodent models, neuroimmune pathways may represent unexplored, nontraditional targets for medication development to reduce alcohol consumption and prevent relapse. Peroxisome proliferator-activated receptor agonists are one class of anti-inflammatory medications that demonstrate antiaddictive properties for alcohol and other drugs of abuse. Expression of immune-related genes is altered in animals and humans following chronic alcohol exposure, and the regulatory influences of specific mRNAs, microRNAs, and activated cell types are areas of intense study. Ultimately, the use of multiple datasets combined with behavioral validation will be needed to link specific neuroimmune pathways to addiction vulnerability.
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215
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Ray LA, Roche DJO, Heinzerling K, Shoptaw S. Opportunities for the development of neuroimmune therapies in addiction. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 118:381-401. [PMID: 25175870 DOI: 10.1016/b978-0-12-801284-0.00012-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Studies have implicated neuroinflammatory processes in the pathophysiology of various psychiatric conditions, including addictive disorders. Neuroimmune signaling represents an important and relatively poorly understood biological process in drug addiction. The objective of this review is to update the field on recent developments in neuroimmune therapies for addiction. First, we review studies of neuroinflammation in relation to alcohol and methamphetamine dependence followed by a section on neuroinflammation and accompanying neurocognitive dysfunction in HIV infection and concomitant substance abuse. Second, we provide a review of pharmacotherapies with neuroimmune properties and their potential development for the treatment of addictions. Pharmacotherapies covered in this review include ibudilast, minocycline, doxycycline, topiramate, indomethacin, rolipram, anakinra (IL-1Ra), peroxisome proliferator-activated receptor agonists, naltrexone, and naloxone. Lastly, summary and future directions are provided with recommendations for how to efficiently translate preclinical findings into clinical studies that can ultimately lead to novel and more effective pharmacotherapies for addiction.
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Affiliation(s)
- Lara A Ray
- Department of Psychology, University of California, Los Angeles, Los Angeles, California, USA.
| | - Daniel J O Roche
- Department of Psychology, University of California, Los Angeles, Los Angeles, California, USA
| | - Keith Heinzerling
- Department of Family Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Steve Shoptaw
- Department of Family Medicine, University of California, Los Angeles, Los Angeles, California, USA
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216
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Abstract
Alcohol-induced brain damage likely contributes to the dysfunctional poor decisions associated with alcohol dependence. Human alcoholics have a global loss of brain volume that is most severe in the frontal cortex. Neuroimmune gene induction by binge drinking increases neurodegeneration through increased oxidative stress, particularly NADPH oxidase-induced oxidative stress. In addition, HMGB1-TLR4 and innate immune NF-κB target genes are increased leading to persistent and sensitized neuroimmune responses to ethanol and other agents that release HMGB1 or directly stimulate TLR receptors and/or NMDA receptors. Neuroimmune signaling and glutamate excitotoxicity are linked to alcoholic neurodegeneration. Models of adolescent alcohol abuse lead to significant frontal cortical degeneration and show the most severe loss of hippocampal neurogenesis. Adolescence is a period of high risk for ethanol-induced neurodegeneration and alterations in brain structure, gene expression, and maturation of adult phenotypes. Together, these findings support the hypothesis that adolescence is a period of risk for persistent and long-lasting increases in brain neuroimmune gene expression that promote persistent and long-term increases in alcohol consumption, neuroimmune gene induction, and neurodegeneration that we find associated with alcohol use disorders.
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Affiliation(s)
- Fulton T Crews
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
| | - Ryan P Vetreno
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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217
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Zeidán-Chuliá F, Salmina AB, Malinovskaya NA, Noda M, Verkhratsky A, Moreira JCF. The glial perspective of autism spectrum disorders. Neurosci Biobehav Rev 2014; 38:160-72. [DOI: 10.1016/j.neubiorev.2013.11.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 11/03/2013] [Accepted: 11/21/2013] [Indexed: 01/01/2023]
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Niciu MJ, Henter ID, Sanacora G, Zarate CA. Glial abnormalities in substance use disorders and depression: does shared glutamatergic dysfunction contribute to comorbidity? World J Biol Psychiatry 2014; 15:2-16. [PMID: 24024876 PMCID: PMC4180366 DOI: 10.3109/15622975.2013.829585] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Preclinical and clinical research in neuropsychiatric disorders, particularly mood and substance use disorders, have historically focused on neurons; however, glial cells-astrocytes, microglia, and oligodendrocytes - also play key roles in these disorders. METHODS Peer-reviewed PubMed/Medline articles published through December 2012 were identified using the following keyword combinations: glia, astrocytes, oligodendrocytes/glia, microglia, substance use, substance abuse, substance dependence, alcohol, opiate, opioid, cocaine, psychostimulants, stimulants, and glutamate. RESULTS Depressive and substance use disorders are highly comorbid, suggesting a common or overlapping aetiology and pathophysiology. Reduced astrocyte cell number occurs in both disorders. Altered glutamate neurotransmission and metabolism - specifically changes in the levels/activity of transporters, receptors, and synaptic proteins potentially related to synaptic physiology - appear to be salient features of both disorders. Glial cell pathology may also underlie the pathophysiology of both disorders via impaired astrocytic production of neurotrophic factors. Microglial/neuroinflammatory pathology is also evident in both depressive and substance use disorders. Finally, oligodendrocyte impairment decreases myelination and impairs expression of myelin-related genes in both substance use and depressive disorders. CONCLUSIONS Glial-mediated glutamatergic dysfunction is a common neuropathological pathway in both substance use and depression. Therefore, glutamatergic neuromodulation is a rational drug target in this comorbidity.
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Affiliation(s)
- Mark J. Niciu
- Yale University Department of Psychiatry/Connecticut Mental Health Center (CMHC), Clinical Neuroscience Research Unit (CNRU), New Haven, CT, USA,Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Ioline D. Henter
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD USA
| | - Gerard Sanacora
- Yale University Department of Psychiatry/Connecticut Mental Health Center (CMHC), Clinical Neuroscience Research Unit (CNRU), New Haven, CT, USA
| | - Carlos A. Zarate
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
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219
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Whitman BA, Knapp DJ, Werner DF, Crews FT, Breese GR. The cytokine mRNA increase induced by withdrawal from chronic ethanol in the sterile environment of brain is mediated by CRF and HMGB1 release. Alcohol Clin Exp Res 2013; 37:2086-97. [PMID: 23895427 PMCID: PMC3815509 DOI: 10.1111/acer.12189] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 05/02/2013] [Indexed: 01/03/2023]
Abstract
BACKGROUND Many neurobiological factors may initiate and sustain alcoholism. Recently, dysregulation of the neuroimmune system by chronic ethanol (CE) has implicated Toll-like receptor 4 (TLR4) activation. Even though TLR4s are linked to CE initiation of brain cytokine mRNAs, the means by which CE influences neuroimmune signaling in brain in the absence of infection remains uncertain. Therefore, the hypothesis is tested that release of an endogenous TLR4 agonist, high-mobility group box 1 (HMGB1) and/or corticotropin-releasing factor (CRF) during CE withdrawal are responsible for CE protocols increasing cytokine mRNAs. METHODS Acute ethanol (EtOH; 2.75 g/kg) and acute lipopolysaccharide (LPS; 250 μg/kg) dosing on cytokine mRNAs are first compared. Then, the effects of chronic LPS exposure (250 μg/kg for 10 days) on cytokine mRNAs are compared with changes induced by CE protocols (15 days of continuous 7% EtOH diet [CE protocol] or 3 intermittent 5-day cycles of 7% EtOH diet [CIE protocol]). Additionally, TLR4, HMGB1, and downstream effector mRNAs are assessed after CE, CIE, and chronic LPS. To test whether HMGB1 and/or CRF support the CE withdrawal increase in cytokine mRNAs, the HMGB1 antagonists, glycyrrhizin and ethyl pyruvate, and a CRF1 receptor antagonist (CRF1RA) are administered during 24 hours of CE withdrawal. RESULTS While cytokine mRNAs were not increased following acute EtOH, acute LPS increased all cytokine mRNAs 4 hours after injection. CE produced no change in cytokine mRNAs prior to CE removal; however, the CE and CIE protocols increased cytokine mRNAs by 24 hours after withdrawal. In contrast, chronic LPS produced no cytokine mRNA changes 24 hours after LPS dosing. TLR4 mRNA was elevated 24 hours following both CE protocols and chronic LPS exposure. While chronic LPS had no effect on HMGB1 mRNA, withdrawal from CE protocols significantly elevated HMGB1 mRNA. Systemic administration of HMGB1 antagonists or a CRF1RA significantly reduced the cytokine mRNA increase following CE withdrawal. The CRF1RA and the HMGB1 antagonist, ethyl pyruvate, also reduced the HMGB1 mRNA increase that followed CE withdrawal. CONCLUSIONS By blocking HMGB1 or CRF action during CE withdrawal, evidence is provided that HMGB1 and CRF release are critical for the CE withdrawal induction of selected brain cytokine mRNAs. Consequently, these results clarify a means by which withdrawal from CE exposure activates neuroimmune function in the sterile milieu of brain.
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Affiliation(s)
- Buddy A Whitman
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Curriculum in Neurobiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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220
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Liu S, Liu YP, Song WB, Song XJ. EphrinB-EphB receptor signaling contributes to bone cancer pain via Toll-like receptor and proinflammatory cytokines in rat spinal cord. Pain 2013; 154:2823-2835. [DOI: 10.1016/j.pain.2013.08.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 08/19/2013] [Accepted: 08/19/2013] [Indexed: 12/29/2022]
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Pascual M, Pla A, Miñarro J, Guerri C. Neuroimmune activation and myelin changes in adolescent rats exposed to high-dose alcohol and associated cognitive dysfunction: a review with reference to human adolescent drinking. Alcohol Alcohol 2013; 49:187-92. [PMID: 24217958 DOI: 10.1093/alcalc/agt164] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AIMS The aim of the study was to assess whether intermittent ethanol administration to adolescent rats activates innate immune response and TLRs signalling causing myelin disruption and long-term cognitive and behavioural deficits. METHODS We used a rat model of intermittent binge-like ethanol exposure during adolescence. RESULTS Binge-like ethanol administration to adolescent rats increased the gene expression of TLR4 and TLR2 in the prefrontal cortex (PFC), as well as inflammatory cytokines TNFα and IL-1β. Up-regulation of TLRs and inflammatory mediators were linked with alterations in the levels of several myelin proteins in the PFC of adolescent rats. These events were associated with previously reported long-term cognitive dysfunctions. Conversely, the same ethanol treatment did not cause significant changes in either inflammatory mediators or myelin changes in the brain of adult rats. CONCLUSION Activation of innate immune receptors TLRs in the PFC appears to be involved in the neuroinflammation and demyelination processes induced by ethanol exposure during adolescence. The findings support the vulnerability of the juvenile brain to the effects of ethanol and the long-term cognitive consequences of binge drinking. In addition, ethanol-induced PFC dysfunctions might underlie the propensity of adolescents for impulsivity and to ignore the negative consequences of their behaviour, both of which could increase the risk of substance abuse.
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Affiliation(s)
- María Pascual
- Corresponding author: Department of Cellular Pathology, Centro de Investigación Príncipe Felipe, C/ Eduardo Primo Yúfera 3, 46012 Valencia, Spain.
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Rajayer SR, Jacob A, Yang WL, Zhou M, Chaung W, Wang P. Cold-inducible RNA-binding protein is an important mediator of alcohol-induced brain inflammation. PLoS One 2013; 8:e79430. [PMID: 24223948 PMCID: PMC3815202 DOI: 10.1371/journal.pone.0079430] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 09/30/2013] [Indexed: 12/05/2022] Open
Abstract
Binge drinking has been associated with cerebral dysfunction. Ethanol induced microglial activation initiates an inflammatory process that causes upregulation of proinflammatory cytokines which in turn creates neuronal inflammation and damage. However, the molecular mechanism is not fully understood. We postulate that cold-inducible RNA-binding protein (CIRP), a novel proinflammatory molecule, can contribute to alcohol-induced neuroinflammation. To test this theory male wild-type (WT) mice were exposed to alcohol at concentrations consistent to binge drinking and blood and brain tissues were collected. At 5 h after alcohol, a significant increase of 53% in the brain of CIRP mRNA was observed and its expression remained elevated at 10 h and 15 h. Brain CIRP protein levels were increased by 184% at 10 h and remained high at 15 h. We then exposed male WT and CIRP knockout (CIRP−/−) mice to alcohol, and blood and brain tissues were collected at 15 h post-alcohol infusion. Serum levels of tissue injury markers (AST, ALT and LDH) were significantly elevated in alcohol-exposed WT mice while they were less increased in the CIRP−/− mice. Brain TNF-α mRNA and protein expressions along with IL-1β protein levels were significantly increased in WT mice, which was not seen in the CIRP−/− mice. In cultured BV2 cells (mouse microglia), ethanol at 100 mM showed an increase of CIRP mRNA by 274% and 408% at 24 h and 48 h respectively. Corresponding increases in TNF-α and IL-1β were also observed. CIRP protein levels were markedly increased in the medium, suggesting that CIRP was secreted by the BV2 cells. From this we conclude that alcohol exposure activates microglia to produce and secrete CIRP and possibly induce pro-inflammatory response and thereby causing neuroinflammation. CIRP could be a novel mediator of alcohol-induced brain inflammation.
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Affiliation(s)
- Salil R. Rajayer
- Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, New York, United States of America
| | - Asha Jacob
- Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, New York, United States of America
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | - Weng-Lang Yang
- Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, New York, United States of America
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | - Mian Zhou
- Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, New York, United States of America
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | - Wayne Chaung
- Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, New York, United States of America
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | - Ping Wang
- Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, New York, United States of America
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
- * E-mail:
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223
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Silverstein PS, Kumar A. HIV-1 and alcohol: interactions in the central nervous system. Alcohol Clin Exp Res 2013; 38:604-10. [PMID: 24134164 DOI: 10.1111/acer.12282] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 08/15/2013] [Indexed: 12/19/2022]
Abstract
The use of alcohol has been associated with both an increased risk of acquisition of HIV-1 infection and an increased rate of disease progression among those already infected by the virus. The potential for alcohol to exacerbate the effects of HIV infection is especially important in the central nervous system (CNS) because this area is vulnerable to the combined effects of alcohol and HIV infection. The effects of alcohol on glial cells are mediated through receptors such as Toll-like receptor 4 and N-methyl-d-aspartate receptor. This causes the activation of signaling molecules such as interleukin-1 receptor-associated kinase and various members of the P38 mitogen-activated protein kinase family and subsequent activation of transcription factors such as nuclear factor-kappa beta and activator protein 1. The eventual outcome is an increase in pro-inflammatory cytokine production by glial cells. Alcohol also induces higher levels of NADPH oxidase in glial cells, which leads to an increased production of reactive oxygen species (ROS). Viral invasion of the CNS occurs early after infection, and HIV proteins have also been demonstrated to increase levels of pro-inflammatory cytokines and ROS in glial cells through activation of some of the same pathways activated by alcohol. Both cell culture systems and animal models have demonstrated that concomitant exposure to alcohol and HIV/HIV proteins results in increased levels of expression of pro-inflammatory cytokines such as interleukin-1 beta and tumor necrosis factor-alpha, along with increased levels of oxidative stress. Clinical studies also suggest that alcohol exacerbates the CNS effects of HIV-1 infection. This review focuses on the mechanisms by which alcohol causes increased CNS damage in HIV-1 infection.
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Affiliation(s)
- Peter S Silverstein
- Division of Pharmacology and Toxicology , School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri
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224
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Qin L, Crews FT. Focal thalamic degeneration from ethanol and thiamine deficiency is associated with neuroimmune gene induction, microglial activation, and lack of monocarboxylic acid transporters. Alcohol Clin Exp Res 2013; 38:657-71. [PMID: 24117525 PMCID: PMC3959259 DOI: 10.1111/acer.12272] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 08/12/2013] [Indexed: 12/19/2022]
Abstract
Background Wernicke's encephalopathy-Korsakoff syndrome (WE-KS) is common in alcoholics, caused by thiamine deficiency (TD; vitamin B1) and associated with lesions to the thalamus (THAL). Although TD alone can cause WE, the high incidence in alcoholism suggests that TD and ethanol (EtOH) interact. Methods Mice in control, TD, or EtOH groups alone or combined were studied after 5 or 10 days of treatment. THAL and entorhinal cortex (ENT) histochemistry and mRNA were assessed. Results Combined EtOH-TD treatment for 5 days (EtOH-TD5) showed activated microglia, proinflammatory gene induction and THAL neurodegeneration that was greater than that found with TD alone (TD5), whereas 10 days resulted in marked THAL degeneration and microglial-neuroimmune activation in both groups. In contrast, 10 days of TD did not cause ENT degeneration. Interestingly, in ENT, TD10 activated microglia and astrocytes more than EtOH-TD10. In THAL, multiple astrocytic markers were lost consistent with glial cell loss. TD blocks glucose metabolism more than acetate. Acetate derived from hepatic EtOH metabolism is transported by monocarboxylic acid transporters (MCT) into both neurons and astrocytes that use acetyl-CoA synthetase (AcCoAS) to generate cellular energy from acetate. MCT and AcCoAS expression in THAL is lower than ENT prompting the hypothesis that focal THAL degeneration is related to insufficient MCT and AcCoAS in THAL. To test this hypothesis, we administered glycerin triacetate (GTA) to increase blood acetate and found it protected the THAL from TD-induced degeneration. Conclusions Our findings suggest that EtOH potentiates TD-induced THAL degeneration through neuroimmune gene induction. The findings support the hypothesis that TD deficiency inhibits global glucose metabolism and that a reduced ability to process acetate for cellular energy results in THAL focal degeneration in alcoholics contributing to the high incidence of Wernicke-Korsakoff syndrome in alcoholism.
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Affiliation(s)
- Liya Qin
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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225
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Agrawal RG, Owen JA, Levin PS, Hewetson A, Berman AE, Franklin SR, Hogue RJ, Chen Y, Walz C, Colvard BD, Nguyen J, Velasquez O, Al-Hasan Y, Blednov YA, Fowler AK, Syapin PJ, Bergeson SE. Bioinformatics analyses reveal age-specific neuroimmune modulation as a target for treatment of high ethanol drinking. Alcohol Clin Exp Res 2013; 38:428-37. [PMID: 24125126 DOI: 10.1111/acer.12288] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 07/16/2013] [Indexed: 01/15/2023]
Abstract
BACKGROUND Use of in silico bioinformatics analyses has led to important leads in the complex nature of alcoholism at the genomic, epigenomic, and proteomic level, but has not previously been successfully translated to the development of effective pharmacotherapies. In this study, a bioinformatics approach led to the discovery of neuroimmune pathways as an age-specific druggable target. Minocycline, a neuroimmune modulator, reduced high ethanol (EtOH) drinking in adult, but not adolescent, mice as predicted a priori. METHODS Age and sex-divergent effects in alcohol consumption were quantified in FVB/NJ × C57BL/6J F1 mice given access to 20% alcohol using a 4 h/d, 4-day drinking-in-dark (DID) paradigm. In silico bioinformatics pathway overrepresentation analysis for age-specific effects of alcohol in brain was performed using gene expression data collected in control and DID-treated, adolescent and adult, male mice. Minocycline (50 mg/kg i.p., once daily) or saline alone was tested for an effect on EtOH intake in the F1 and C57BL/6J (B6) mice across both age and gender groups. Effects of minocycline on the pharmacokinetic properties of alcohol were evaluated by comparing the rates of EtOH elimination between the saline- and minocycline-treated F1 and B6 mice. RESULTS Age and gender differences in DID consumption were identified. Only males showed a clear developmental increase difference in drinking over time. In silico analyses revealed neuroimmune-related pathways as significantly overrepresented in adult, but not in adolescent, male mice. As predicted, minocycline treatment reduced drinking in adult, but not adolescent, mice. The age effect was present for both genders, and in both the F1 and B6 mice. Minocycline had no effect on the pharmacokinetic elimination of EtOH. CONCLUSIONS Our results are a proof of concept that bioinformatics analysis of brain gene expression can lead to the generation of new hypotheses and a positive translational outcome for individualized pharmacotherapeutic treatment of high alcohol consumption.
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Affiliation(s)
- Rajiv G Agrawal
- Department of Pharmacology and Neuroscience, South Plains Alcohol and Addiction Research Center, Texas Tech University Health Science Center, Lubbock, Texas
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226
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Abstract
Chronic consumption of a large amount of alcohol disrupts the communication between nervous, endocrine, and immune system and causes hormonal disturbances that lead to profound and serious consequences at physiologic and behavioral levels. These alcohol-induced hormonal dysregulations affect the entire body and can result in various disorders such as stress abnormalities, reproductive deficits, body growth defect, thyroid problems, immune dysfunction, cancers, bone disease, and psychological and behavioral disorders. This review summarizes the findings from human and animal studies that provide consistent evidence on the various effects of alcohol abuse on the endocrine system.
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Affiliation(s)
- Nadia Rachdaoui
- Nadia Rachdaoui, Ph.D., Rutgers Endocrine Research Program. Department of Animal Sciences Rutgers University, 67 Poultry Farm Lane, New Brunswick, NJ 08901,
| | - Dipak K. Sarkar
- Dipak K. Sarkar, Ph.D., D. Phil., Rutgers Endocrine Research Program. Department of Animal Sciences, Rutgers University, 67 Poultry Farm Lane, New Brunswick, NJ 08901,
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227
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Alfonso-Loeches S, Pascual M, Guerri C. Gender differences in alcohol-induced neurotoxicity and brain damage. Toxicology 2013; 311:27-34. [DOI: 10.1016/j.tox.2013.03.001] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 02/18/2013] [Accepted: 03/03/2013] [Indexed: 02/07/2023]
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228
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Marshall SA, McClain JA, Kelso ML, Hopkins DM, Pauly JR, Nixon K. Microglial activation is not equivalent to neuroinflammation in alcohol-induced neurodegeneration: The importance of microglia phenotype. Neurobiol Dis 2013; 54:239-51. [PMID: 23313316 PMCID: PMC3629000 DOI: 10.1016/j.nbd.2012.12.016] [Citation(s) in RCA: 185] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 12/21/2012] [Accepted: 12/28/2012] [Indexed: 12/19/2022] Open
Abstract
Excessive alcohol intake, a defining characteristic of an alcohol use disorder (AUD), results in neurodegeneration in the hippocampus and entorhinal cortex that has been linked to a variety of cognitive deficits. Neuroinflammation is thought to be a factor in alcohol-induced neurodegeneration, and microglia activation is a key but not sole component of an inflammatory response. These experiments investigate the effects of ethanol exposure in a well-accepted model of an AUD on both microglial activation and blood brain barrier disruption (BBB) in order to understand their relationship to classical definitions of inflammation and alcohol-induced neurodegeneration. Following a four-day binge ethanol paradigm, rat hippocampal and entorhinal cortex tissue was examined using three distinct approaches to determine microglia phenotype and BBB disruption: immunohistochemistry, autoradiography, and ELISA. After ethanol exposure, there was an increase in [(3)H]-PK-11195 binding and OX-42 immunoreactivity indicative of microglial activation; however, microglia were not fully activated since both OX-6 and ED-1 immunoreactive microglia were absent. This data was supported by functional evidence as there was no increase in the proinflammatory cytokines IL-6 or TNF-α, but a 26% increase in the anti-inflammatory cytokine, IL-10, and a 38% increase in the growth factor, TGF-β, seven days after exposure. Furthermore, there was no evidence of a disruption of the BBB. These data suggest that the four-day binge model of an AUD, which produces neurodegeneration in corticolimbic regions, does not elicit classical neuroinflammation but instead produces partially activated microglia. Partial activation of microglia following binge ethanol exposure suggest that microglia in this model have beneficial or homeostatic roles rather than directly contributing to neurodegeneration and are a consequence of alcohol-induced-damage instead of the source of damage.
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Affiliation(s)
- S. Alex Marshall
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
| | - Justin A. McClain
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
| | | | - Deann M. Hopkins
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
| | - James R. Pauly
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
| | - Kimberly Nixon
- Department of Pharmaceutical Sciences, The University of Kentucky, Lexington, KY 40536-0596
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Fernandez-Lizarbe S, Montesinos J, Guerri C. Ethanol induces TLR4/TLR2 association, triggering an inflammatory response in microglial cells. J Neurochem 2013; 126:261-73. [PMID: 23600947 DOI: 10.1111/jnc.12276] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 04/11/2013] [Accepted: 04/17/2013] [Indexed: 02/06/2023]
Abstract
Alcohol consumption can induce brain damage, demyelination, and neuronal death, although the mechanisms are poorly understood. Toll-like receptors are sensors of the innate immune system and their activation induces inflammatory processes. We have reported that ethanol activates and recruits Toll-like receptor (TLR)4 receptors within the lipid rafts of glial cells, triggering the production of inflammatory mediators and causing neuroinflammation. Since TLR2 can also participate in the glial response and in the neuroinflammation, we investigate the effects of ethanol on TLR4/TLR2 responses. Here, we demonstrate that ethanol up-regulates TLR4 and TLR2 expression in microglial cells, inducing the production of inflammatory mediators which triggers reactive oxygen species generation and neuronal apoptosis. Ethanol also promotes TLR4/TLR2 recruitment into lipid rafts-caveolae, mimicking their activation by their ligands, lipopolysaccharide, and lipoteichoic acid (LTA). Immunoprecipitation and confocal microscopy studies reveal that ethanol induces a physical association between TLR2 and TLR4 receptors, suggesting the formation of heterodimers. Using microglia from either TLR2 or TLR4 knockout mice, we show that TLR2 potentiates the effects of ethanol on the TLR4 response reflected by the activation of MAPKs and inducible NO synthase. In summary, we provide evidence for a mechanism by which ethanol triggers TLR4/TLR2 association contributing to the neuroinflammation and neurodegeneration associated with alcohol abuse.
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Affiliation(s)
- Sara Fernandez-Lizarbe
- Department of Cellular Pathology, Príncipe Felipe Research Centre, Eduardo Primo Yúfera, Valencia, Spain
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230
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Lewis SS, Hutchinson MR, Zhang Y, Hund DK, Maier SF, Rice KC, Watkins LR. Glucuronic acid and the ethanol metabolite ethyl-glucuronide cause toll-like receptor 4 activation and enhanced pain. Brain Behav Immun 2013; 30:24-32. [PMID: 23348028 PMCID: PMC3641160 DOI: 10.1016/j.bbi.2013.01.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 12/19/2022] Open
Abstract
We have previously observed that the non-opioid morphine metabolite, morphine-3-glucuronide, enhances pain via a toll-like receptor 4 (TLR4) dependent mechanism. The present studies were undertaken to determine whether TLR4-dependent pain enhancement generalizes to other classes of glucuronide metabolites. In silico modeling predicted that glucuronic acid alone and ethyl glucuronide, a minor but long-lasting ethanol metabolite, would dock to the same MD-2 portion of the TLR4 receptor complex previously characterized as the docking site for morphine-3-glucuronide. Glucuronic acid, ethyl glucuronide and ethanol all caused an increase in TLR4-dependent reporter protein expression in a cell line transfected with TLR4 and associated co-signaling molecules. Glucuronic acid-, ethyl glucuronide-, and ethanol-induced increases in TLR4 signaling were blocked by the TLR4 antagonists LPS-RS and (+)-naloxone. Glucuronic acid and ethyl glucuronide both caused allodynia following intrathecal injection in rats, which was blocked by intrathecal co-administration of the TLR4 antagonist LPS-RS. The finding that ethyl glucuronide can cause TLR4-dependent pain could have implications for human conditions such as hangover headache and alcohol withdrawal hyperalgesia, as well as suggesting that other classes of glucuronide metabolites could have similar effects.
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Affiliation(s)
- Susannah S. Lewis
- Department of Psychology & Neuroscience, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Mark R. Hutchinson
- Discipline of Pharmacology and Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Yingning Zhang
- Department of Psychology & Neuroscience, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Dana K. Hund
- Department of Psychology & Neuroscience, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Steven F. Maier
- Department of Psychology & Neuroscience, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Kenner C. Rice
- Chemical Biology Research Branch, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism National Institutes of Health, Rockville, Maryland, USA
| | - Linda R. Watkins
- Department of Psychology & Neuroscience, University of Colorado at Boulder, Boulder, Colorado, USA,Corresponding author: Linda R. Watkins, Department of Psychology, Campus Box 345, University of Colorado at Boulder, Boulder, Colorado, USA 80309-0345, , Fax: (303) 492-2967, Phone: (303) 492-7034
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231
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Lippai D, Bala S, Petrasek J, Csak T, Levin I, Kurt-Jones EA, Szabo G. Alcohol-induced IL-1β in the brain is mediated by NLRP3/ASC inflammasome activation that amplifies neuroinflammation. J Leukoc Biol 2013; 94:171-82. [PMID: 23625200 DOI: 10.1189/jlb.1212659] [Citation(s) in RCA: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Alcohol-induced neuroinflammation is mediated by proinflammatory cytokines, including IL-1β. IL-1β production requires caspase-1 activation by inflammasomes-multiprotein complexes that are assembled in response to danger signals. We hypothesized that alcohol-induced inflammasome activation contributes to increased IL-1β in the brain. WT and TLR4-, NLRP3-, and ASC-deficient (KO) mice received an ethanol-containing or isocaloric control diet for 5 weeks, and some received the rIL-1ra, anakinra, or saline treatment. Inflammasome activation, proinflammatory cytokines, endotoxin, and HMGB1 were measured in the cerebellum. Expression of inflammasome components (NLRP1, NLRP3, ASC) and proinflammatory cytokines (TNF-α, MCP-1) was increased in brains of alcohol-fed compared with control mice. Increased caspase-1 activity and IL-1β protein in ethanol-fed mice indicated inflammasome activation. TLR4 deficiency protected from TNF-α, MCP-1, and attenuated alcohol-induced IL-1β increases. The TLR4 ligand, LPS, was not increased in the cerebellum. However, we found up-regulation of acetylated and phosphorylated HMGB1 and increased expression of the HMGB1 receptors (TLR2, TLR4, TLR9, RAGE) in alcohol-fed mice. NLRP3- or ASC-deficient mice were protected from caspase-1 activation and alcohol-induced IL-1β increase in the brain. Furthermore, in vivo treatment with rIL-1ra prevented alcohol-induced inflammasome activation and IL-1β, TNF-α, and acetylated HMGB1 increases in the cerebellum. Conversely, intracranial IL-1β administration induced TNF-α and MCP-1 in the cerebellum. In conclusion, alcohol up-regulates and activates the NLRP3/ASC inflammasome, leading to caspase-1 activation and IL-1β increase in the cerebellum. IL-1β amplifies neuroinflammation, and disruption of IL-1/IL-1R signaling prevents alcohol-induced inflammasome activation and neuroinflammation. Increased levels of acetylated and phosphorylated HMGB1 may contribute to alcoholic neuroinflammation.
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Affiliation(s)
- Dora Lippai
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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232
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Bell-Temin H, Zhang P, Chaput D, King MA, You M, Liu B, Stevens SM. Quantitative Proteomic Characterization of Ethanol-Responsive Pathways in Rat Microglial Cells. J Proteome Res 2013; 12:2067-77. [DOI: 10.1021/pr301038f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Harris Bell-Temin
- Department
of Cell Biology,
Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620,
United States
| | | | - Dale Chaput
- Department
of Cell Biology,
Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620,
United States
| | - Michael A. King
- Department of Veterans Affairs Medical Center, 1601 SW Archer Road, Gainesville,
Florida 32608, United States
| | - Min You
- Department of Molecular Pharmacology
and Physiology, University of South Florida, 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
| | | | - Stanley M. Stevens
- Department
of Cell Biology,
Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620,
United States
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Crews FT, Qin L, Sheedy D, Vetreno RP, Zou J. High mobility group box 1/Toll-like receptor danger signaling increases brain neuroimmune activation in alcohol dependence. Biol Psychiatry 2013; 73:602-12. [PMID: 23206318 PMCID: PMC3602398 DOI: 10.1016/j.biopsych.2012.09.030] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/30/2012] [Accepted: 09/19/2012] [Indexed: 12/30/2022]
Abstract
BACKGROUND Innate immune gene expression is regulated in part through high mobility group box 1 (HMGB1), an endogenous proinflammatory cytokine, that activates multiple members of the interleukin-1/Toll-like receptor (TLR) family associated with danger signaling. We investigated expression of HMGB1, TLR2, TLR3, and TLR4 in chronic ethanol-treated mouse brain, postmortem human alcoholic brain, and rat brain slice culture to test the hypothesis that neuroimmune activation in alcoholic brain involves ethanol activation of HMGB1/TLR danger signaling. METHODS Protein levels were assessed using Western blot, enzyme-linked immunosorbent assay, and immunohistochemical immunoreactivity (+IR), and messenger RNA (mRNA) levels were measured by real time polymerase chain reaction in ethanol-treated mice (5 g/kg/day, intragastric, 10 days + 24 hours), rat brain slice culture, and postmortem human alcoholic brain. RESULTS Ethanol treatment of mice increased brain mRNA and +IR protein expression of HMGB1, TLR2, TLR3, and TLR4. Postmortem human alcoholic brain also showed increased HMGB1, TLR2, TLR3, and TLR4 +IR cells that correlated with lifetime alcohol consumption, as well as each other. Ethanol treatment of brain slice culture released HMGB1 into the media and induced the proinflammatory cytokine, interleukin-1 beta (IL-1β). Neutralizing antibodies to HMGB1 and small inhibitory mRNA to HMGB1 or TLR4 blunted ethanol induction of IL-1β. CONCLUSIONS Ethanol-induced HMGB1/TLR signaling contributes to induction of the proinflammatory cytokine, IL-1β. Increased expression of HMGB1, TLR2, TLR3, and TLR4 in alcoholic brain and in mice treated with ethanol suggests that chronic alcohol-induced brain neuroimmune activation occurs through HMGB1/TLR signaling.
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Affiliation(s)
- Fulton T Crews
- Bowles Center for Alcohol Studies, Department of Pharmacology and Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7178, USA.
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Qin X, Sun ZQ, Zhang XW, Dai XJ, Mao SS, Zhang YM. TLR4 signaling is involved in the protective effect of propofol in BV2 microglia against OGD/reoxygenation. J Physiol Biochem 2013; 69:707-18. [DOI: 10.1007/s13105-013-0247-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
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235
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Neuroimmune signaling: a key component of alcohol abuse. Curr Opin Neurobiol 2013; 23:513-20. [PMID: 23434064 DOI: 10.1016/j.conb.2013.01.024] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/16/2013] [Accepted: 01/24/2013] [Indexed: 12/13/2022]
Abstract
Molecular and behavioral studies corroborate a pivotal role for the innate immune system in mediating the acute and chronic effects of alcohol and support a neuroimmune hypothesis of alcohol addiction. Changes in expression of neuroimmune genes and microglial transcripts occur in postmortem brain from alcoholics and animals exposed to alcohol, and null mutant animals lacking certain innate immune genes show decreased alcohol-mediated responses. Many of the differentially expressed genes are part of the toll like receptor (TLR) signaling pathway and culminate in an increased expression of pro-inflammatory immune genes. Compounds known to inhibit inflammation, microglial activation, and neuroimmune gene expression have shown promising results in reducing alcohol-mediated behaviors in animal models, indicating that neuroimmune signaling pathways offer unexplored targets in the treatment of alcohol abuse.
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236
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Yao L, Kan EM, Lu J, Hao A, Dheen ST, Kaur C, Ling EA. Toll-like receptor 4 mediates microglial activation and production of inflammatory mediators in neonatal rat brain following hypoxia: role of TLR4 in hypoxic microglia. J Neuroinflammation 2013; 10:23. [PMID: 23388509 PMCID: PMC3575244 DOI: 10.1186/1742-2094-10-23] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/25/2013] [Indexed: 11/20/2022] Open
Abstract
Background Hypoxia induces microglial activation which causes damage to the developing brain. Microglia derived inflammatory mediators may contribute to this process. Toll-like receptor 4 (TLR4) has been reported to induce microglial activation and cytokines production in brain injuries; however, its role in hypoxic injury remains uncertain. We investigate here TLR4 expression and its roles in neuroinflammation in neonatal rats following hypoxic injury. Methods One day old Wistar rats were subjected to hypoxia for 2 h. Primary cultured microglia and BV-2 cells were subjected to hypoxia for different durations. TLR4 expression in microglia was determined by RT-PCR, western blot and immunofluorescence staining. Small interfering RNA (siRNA) transfection and antibody neutralization were employed to downregulate TLR4 in BV-2 and primary culture. mRNA and protein expression of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) was assessed. Reactive oxygen species (ROS), nitric oxide (NO) and NF-κB levels were determined by flow cytometry, colorimetric and ELISA assays respectively. Hypoxia-inducible factor-1 alpha (HIF-1α) mRNA and protein expression was quantified and where necessary, the protein expression was depleted by antibody neutralization. In vivo inhibition of TLR4 with CLI-095 injection was carried out followed by investigation of inflammatory mediators expression via double immunofluorescence staining. Results TLR4 immunofluorescence and protein expression in the corpus callosum and cerebellum in neonatal microglia were markedly enhanced post-hypoxia. In vitro, TLR4 protein expression was significantly increased in both primary microglia and BV-2 cells post-hypoxia. TLR4 neutralization in primary cultured microglia attenuated the hypoxia-induced expression of TNF-α, IL-1β and iNOS. siRNA knockdown of TLR4 reduced hypoxia-induced upregulation of TNF-α, IL-1β, iNOS, ROS and NO in BV-2 cells. TLR4 downregulation-mediated inhibition of inflammatory cytokines in primary microglia and BV-2 cells was accompanied by the suppression of NF-κB activation. Furthermore, HIF-1α antibody neutralization attenuated the increase of TLR4 expression in hypoxic BV-2 cells. TLR4 inhibition in vivo attenuated the immunoexpression of TNF-α, IL-1β and iNOS on microglia post-hypoxia. Conclusion Activated microglia TLR4 expression mediated neuroinflammation via a NF-κB signaling pathway in response to hypoxia. Hence, microglia TLR4 presents as a potential therapeutic target for neonatal hypoxia brain injuries.
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Affiliation(s)
- Linli Yao
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong Provincial Key Laboratory of Mental Disorders, Department of Histology and Embryology, Shandong University School of Medicine, 250012, Jinan, China
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237
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Zhao YN, Wang F, Fan YX, Ping GF, Yang JY, Wu CF. Activated microglia are implicated in cognitive deficits, neuronal death, and successful recovery following intermittent ethanol exposure. Behav Brain Res 2013; 236:270-282. [DOI: 10.1016/j.bbr.2012.08.052] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 08/25/2012] [Accepted: 08/30/2012] [Indexed: 11/26/2022]
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238
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Vetreno RP, Crews FT. Adolescent binge drinking increases expression of the danger signal receptor agonist HMGB1 and Toll-like receptors in the adult prefrontal cortex. Neuroscience 2012; 226:475-88. [PMID: 22986167 DOI: 10.1016/j.neuroscience.2012.08.046] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 08/09/2012] [Accepted: 08/23/2012] [Indexed: 02/02/2023]
Abstract
Adolescence is a critical developmental stage of life during which the prefrontal cortex (PFC) matures, and binge drinking and alcohol abuse are common. Recent studies have found that ethanol increases neuroinflammation via upregulated high-mobility group box 1 (HMGB1) signaling through Toll-like receptors (TLRs). HMGB1/TLR 'danger signaling' induces multiple brain innate immune genes that could alter brain function. To determine whether adolescent binge drinking persistently increases innate immune gene expression in the PFC, rats (P25-P55) were exposed to adolescent intermittent ethanol (AIE [5.0 g/kg, 2-day on/2-day off schedule]). On P56, HMGB1/TLR danger signaling was assessed using immunohistochemistry (i.e., +immunoreactivity [+IR]). In a separate group of subjects, spatial and reversal learning on the Barnes maze was assessed in early adulthood (P64-P75), and HMGB1/TLR danger signaling was measured using immunohistochemistry for +IR and RT-PCR for mRNA in adulthood (P80). Immunohistochemical assessment at P56 and 24 days later at P80 revealed increased frontal cortical HMGB1, TLR4, and TLR3 in the AIE-treated rats. Adolescent intermittent ethanol treatment did not alter adult spatial learning on the Barnes maze, but did cause reversal learning deficits and increased perseverative behavior. Barnes maze deficits correlated with the expression of danger signal receptors in the PFC. Taken together, these findings provide evidence that adolescent binge drinking leads to persistent upregulation of innate immune danger signaling in the adult PFC that correlates with adult neurocognitive dysfunction.
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Affiliation(s)
- R P Vetreno
- The Bowles Center for Alcohol Studies, Department of Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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239
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Wu Y, Lousberg EL, Moldenhauer LM, Hayball JD, Coller JK, Rice KC, Watkins LR, Somogyi AA, Hutchinson MR. Inhibiting the TLR4-MyD88 signalling cascade by genetic or pharmacological strategies reduces acute alcohol-induced sedation and motor impairment in mice. Br J Pharmacol 2012; 165:1319-29. [PMID: 21955045 DOI: 10.1111/j.1476-5381.2011.01572.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Emerging evidence implicates a role for toll-like receptor 4 (TLR4) in the CNS effects of alcohol. The aim of the current study was to determine whether TLR4-MyD88-dependent signalling is involved in the acute behavioural actions of alcohol and if alcohol can activate TLR4-downstream MAPK and NF-κB pathways. EXPERIMENTAL APPROACH The TLR4 pathway was evaluated using the TLR4 antagonist (+)-naloxone (µ-opioid receptor-inactive isomer) and mice with null mutations in the TLR4 and MyD88 genes. Sedation and motor impairment induced by a single dose of alcohol were assessed by loss of righting reflex (LORR) and rotarod tests, separately. The phosphorylation of JNK, ERK and p38, and levels of IκBα were measured to determine the effects of acute alcohol exposure on MAPK and NF-κB signalling. KEY RESULTS After a single dose of alcohol, both pharmacological inhibition of TLR4 signalling with (+)-naloxone and genetic deficiency of TLR4 or MyD88 significantly (P < 0.0001) reduced the duration of LORR by 45-78% and significantly decreased motor impairment recovery time to 62-88% of controls. These behavioural actions were not due to changes in the peripheral or central alcohol pharmacokinetics. IκBα levels responded to alcohol by 30 min in mixed hippocampal cell samples, from wild-type mice, but not in cells from TLR4- or MyD88-deficient mice. CONCLUSIONS AND IMPLICATIONS These data provide new evidence that TLR4-MyD88 signalling is involved in the acute behavioural actions of alcohol in mice.
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Affiliation(s)
- Yue Wu
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, South Australia, Australia
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240
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Kane CJM, Phelan KD, Drew PD. Neuroimmune mechanisms in fetal alcohol spectrum disorder. Dev Neurobiol 2012; 72:1302-16. [PMID: 22623427 DOI: 10.1002/dneu.22035] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/15/2012] [Indexed: 12/24/2022]
Abstract
Fetal alcohol spectrum disorder (FASD) is a major health concern worldwide and results from maternal consumption of alcohol during pregnancy. It produces tremendous individual, social, and economic losses. This review will first summarize the structural, functional, and behavior changes seen in FASD. The development of the neuroimmune system will be then be described with particular emphasis on the role of microglial cells in the normal regulation of homeostatic function in the central nervous system (CNS) including synaptic transmission. The impact of alcohol on the neuroimmune system in the developing CNS will be discussed in the context of several key immune molecules and signaling pathways involved in neuroimmune mechanisms that contribute to FASD. This review concludes with a summary of the development of early therapeutic approaches utilizing immunosuppressive drugs to target alcohol-induced pathologies. The significant role played by neuroimmune mechanisms in alcohol addiction and pathology provides a focus for future research aimed at understanding and treating the consequences of FASD.
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Affiliation(s)
- Cynthia J M Kane
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
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241
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Corrigan F, Hutchinson M. Are the effects of alcohol on the CNS influenced by Toll-like receptor signaling? Expert Rev Clin Immunol 2012; 8:201-3. [PMID: 22390481 DOI: 10.1586/eci.11.99] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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242
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Chronic ethanol increases systemic TLR3 agonist-induced neuroinflammation and neurodegeneration. J Neuroinflammation 2012; 9:130. [PMID: 22709825 PMCID: PMC3412752 DOI: 10.1186/1742-2094-9-130] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 06/18/2012] [Indexed: 11/30/2022] Open
Abstract
Background Increasing evidence links systemic inflammation to neuroinflammation and neurodegeneration. We previously found that systemic endotoxin, a TLR4 agonist or TNFα, increased blood TNFα that entered the brain activating microglia and persistent neuroinflammation. Further, we found that models of ethanol binge drinking sensitized blood and brain proinflammatory responses. We hypothesized that blood cytokines contribute to the magnitude of neuroinflammation and that ethanol primes proinflammatory responses. Here, we investigate the effects of chronic ethanol on neuroinflammation and neurodegeneration triggered by toll-like receptor 3 (TLR3) agonist poly I:C. Methods Polyinosine-polycytidylic acid (poly I:C) was used to induce inflammatory responses when sensitized with D-galactosamine (D-GalN). Male C57BL/6 mice were treated with water or ethanol (5 g/kg/day, i.g., 10 days) or poly I:C (250 μg/kg, i.p.) alone or sequentially 24 hours after ethanol exposure. Cytokines, chemokines, microglial morphology, NADPH oxidase (NOX), reactive oxygen species (ROS), high-mobility group box 1 (HMGB1), TLR3 and cell death markers were examined using real-time PCR, ELISA, immunohistochemistry and hydroethidine histochemistry. Results Poly I:C increased blood and brain TNFα that peaked at three hours. Blood levels returned within one day, whereas brain levels remained elevated for at least three days. Escalating blood and brain proinflammatory responses were found with ethanol, poly I:C, and ethanol-poly I:C treatment. Ethanol pretreatment potentiated poly I:C-induced brain TNFα (345%), IL-1β (331%), IL-6 (255%), and MCP-1(190%). Increased levels of brain cytokines coincided with increased microglial activation, NOX gp91phox, superoxide and markers of neurodegeneration (activated caspase-3 and Fluoro-Jade B). Ethanol potentiation of poly I:C was associated with ethanol-increased expression of TLR3 and endogenous agonist HMGB1 in the brain. Minocycline and naltrexone blocked microglial activation and neurodegeneration. Conclusions Chronic ethanol potentiates poly I:C blood and brain proinflammatory responses. Poly I:C neuroinflammation persists after systemic responses subside. Increases in blood TNFα, IL-1β, IL-6, and MCP-1 parallel brain responses consistent with blood cytokines contributing to the magnitude of neuroinflammation. Ethanol potentiation of TLR3 agonist responses is consistent with priming microglia-monocytes and increased NOX, ROS, HMGB1-TLR3 and markers of neurodegeneration. These studies indicate that TLR3 agonists increase blood cytokines that contribute to neurodegeneration and that ethanol binge drinking potentiates these responses.
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Effects of triptolide on the synaptophysin expression of hippocampal neurons in the AD cellular model. Int Immunopharmacol 2012; 13:175-80. [DOI: 10.1016/j.intimp.2012.03.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 03/10/2012] [Accepted: 03/21/2012] [Indexed: 11/22/2022]
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Freeman K, Brureau A, Vadigepalli R, Staehle MM, Brureau MM, Gonye GE, Hoek JB, Hooper DC, Schwaber JS. Temporal changes in innate immune signals in a rat model of alcohol withdrawal in emotional and cardiorespiratory homeostatic nuclei. J Neuroinflammation 2012; 9:97. [PMID: 22626265 PMCID: PMC3411448 DOI: 10.1186/1742-2094-9-97] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 05/24/2012] [Indexed: 02/08/2023] Open
Abstract
Background Chronic alcohol use changes the brain’s inflammatory state. However, there is little work examining the progression of the cytokine response during alcohol withdrawal, a period of profound autonomic and emotional upset. This study examines the inflammatory response in the central nucleus of the amygdala (CeA) and dorsal vagal complex (DVC), brain regions neuroanatomically associated with affective and cardiorespiratory regulation in an in vivo rat model of withdrawal following a single chronic exposure. Methods For qRT-PCR studies, we measured the expression of TNF-α, NOS-2, Ccl2 (MCP-1), MHC II invariant chain CD74, and the TNF receptor Tnfrsf1a in CeA and DVC samples from adult male rats exposed to a liquid alcohol diet for thirty-five days and in similarly treated animals at four hours and forty-eight hours following alcohol withdrawal. ANOVA was used to identify statistically significant treatment effects. Immunohistochemistry (IHC) and confocal microscopy were performed in a second set of animals during chronic alcohol exposure and subsequent 48-hour withdrawal. Results Following a chronic alcohol exposure, withdrawal resulted in a statistically significant increase in the expression of mRNAs specific for innate immune markers Ccl2, TNF-α, NOS-2, Tnfrsf1a, and CD74. This response was present in both the CeA and DVC and most prominent at 48 hours. Confocal IHC of samples taken 48 hours into withdrawal demonstrate the presence of TNF-α staining surrounding cells expressing the neural marker NeuN and endothelial cells colabeled with ICAM-1 (CD54) and RECA-1, markers associated with an inflammatory response. Again, findings were consistent in both brain regions. Conclusions This study demonstrates the rapid induction of Ccl2, TNF-α, NOS-2, Tnfrsf1a and CD74 expression during alcohol withdrawal in both the CeA and DVC. IHC dual labeling showed an increase in TNF-α surrounding neurons and ICAM-1 on vascular endothelial cells 48 hours into withdrawal, confirming the inflammatory response at the protein level. These findings suggest that an abrupt cessation of alcohol intake leads to an acute central nervous system (CNS) inflammatory response in these regions that regulate autonomic and emotional state.
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Affiliation(s)
- Kate Freeman
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
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Alfonso-Loeches S, Pascual M, Gómez-Pinedo U, Pascual-Lucas M, Renau-Piqueras J, Guerri C. Toll-like receptor 4 participates in the myelin disruptions associated with chronic alcohol abuse. Glia 2012; 60:948-64. [PMID: 22431236 DOI: 10.1002/glia.22327] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 02/24/2012] [Indexed: 11/06/2022]
Abstract
Alcohol abuse and alcoholism can cause brain damage, loss of white matter, myelin fiber disruption, and even neuronal injury. The underlying mechanisms of these alterations remain elusive. We have shown that chronic ethanol intake, by activating glial toll-like receptor 4 (TLR4) receptors, triggers the production of inflammatory mediators and can cause brain damage. Because neuroinflammation may be associated with demyelination and neuronal damage, we evaluate whether the ethanol-induced TLR4-dependent proinflammatory environment in the brain could be involved in the myelin disruptions observed in alcoholics. Using brains from wild-type (WT) and TLR4 knockout (KO, TLR4(-/-) ) mice, we demonstrate that chronic ethanol treatment downregulated proteins involved in myelination [proteolipid protein (PLP), myelin basic protein (MBP), myelin-oligodendrocyte glycoprotein, 2,3-cyclic-nucleotide-3-phosphodiesterase, and myelin-associated glycoprotein], while increased chondroitin sulfate proteoglycan NG2 (NG2)-proteoglycan in several brain regions of ethanol-treated WT mice. The immunohistochemistry analysis also revealed that ethanol-treatment-altered myelin morphology reduced the number of MBP-positive fibers and caused oligodendrocyte death, as demonstrated by an increase in caspase-3-positive oligodendrocytes. The in vivo imaging system further confirmed that chronic ethanol intake markedly reduced the PLP in WT mice. Most myelin alterations were not observed in brains from ethanol-treated TLR4(-/-) mice. Electron microscopy studies revealed that although 41-47% of axons showed myelin sheath disarrangements in the cerebral cortex and corpus callosum of WT ethanol-treated mice, respectively, small focal fiber disruptions were noticed in these brain areas of ethanol-treated TLR4(-/-) mice. In summary, the present results suggest that ethanol-induced neuroinflammation might be involved in myelin disruptions and white matter loss observed in human alcoholics.
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Affiliation(s)
- Silvia Alfonso-Loeches
- Department of Cellular Pathology, Príncipe Felipe Research Centre, Avda. Autopista del Saler 16, Valencia, Spain
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Coller JK, Hutchinson MR. Implications of central immune signaling caused by drugs of abuse: mechanisms, mediators and new therapeutic approaches for prediction and treatment of drug dependence. Pharmacol Ther 2012; 134:219-45. [PMID: 22316499 DOI: 10.1016/j.pharmthera.2012.01.008] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 01/12/2023]
Abstract
In the past two decades a trickle of manuscripts examining the non-neuronal central nervous system immune consequences of the drugs of abuse has now swollen to a significant body of work. Initially, these studies reported associative evidence of central nervous system proinflammation resulting from exposure to the drugs of abuse demonstrating key implications for neurotoxicity and disease progression associated with, for example, HIV infection. However, more recently this drug-induced activation of central immune signaling is now understood to contribute substantially to the pharmacodynamic actions of the drugs of abuse, by enhancing the engagement of classical mesolimbic dopamine reward pathways and withdrawal centers. This review will highlight the key in vivo animal, human, biological and molecular evidence of these central immune signaling actions of opioids, alcohol, cocaine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA). Excitingly, this new appreciation of central immune signaling activity of drugs of abuse provides novel therapeutic interventions and opportunities to identify 'at risk' individuals through the use of immunogenetics. Discussion will also cover the evidence of modulation of this signaling by existing clinical and pre-clinical drug candidates, and novel pharmacological targets. Finally, following examination of the breadth of central immune signaling actions of the drugs of abuse highlighted here, the current known common immune signaling components will be outlined and their impact on established addiction neurocircuitry discussed, thereby synthesizing a common neuroimmune hypothesis of addiction.
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Affiliation(s)
- Janet K Coller
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, South Australia 5005, Australia.
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Park SM, Yan BC, Park JH, Choi JH, Yoo KY, Lee CH, Baek YY, Kim YM, Kang IJ, Won MH. Gliosis in the mouse hippocampus without neuronal death after systemic administration of high dosage of tetanus toxin. Cell Mol Neurobiol 2011; 32:423-34. [PMID: 22138813 DOI: 10.1007/s10571-011-9772-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 11/09/2011] [Indexed: 10/15/2022]
Abstract
Tetanus toxin (TeT), an exotoxin, has been studied to cause tetanus in mammalian brains, and it can block the release of some neurotransmitters and affect seizure propagation. In the present study, we investigated neuronal damage/death and glial changes in the mouse hippocampus after systemic administration (intraperitoneal injection) of TeT 10 and 100 ng/kg. In both the 10 and 100 ng/kg TeT-treated groups, no neuronal death occurred in any subregions of the mouse hippocampus until 24 h post-treatment; however, there were changes in glia in the hippocampus depending on time course and dosage. The morphology of GFAP-immunoreactive astrocytes and Iba-1-immunoreactive microglia was apparently changed in the 100 ng/kg TeT treated-group compared to the 10 ng/kg TeT treated-group. In the 100 ng/kg TeT treated-group, they were increased in size and their immunoreactivity was distinctively increased from 12 h post-treatment. We also found that their protein levels were increased in the hippocampus at 12 h post-treatment of 100 ng/kg TeT. In conclusion, these results indicate that the systemic administration of 100 ng/kg TeT induced a distinctive microglia changes in the mouse hippocampus without any neuronal death/damage.
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Affiliation(s)
- Seung Min Park
- Department of Emergency Medicine, College of Medicine, Hallym University Sacred Heart Hospital, Hallym University, Anyang, South Korea
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Alfonso-Loeches S, Guerri C. Molecular and behavioral aspects of the actions of alcohol on the adult and developing brain. Crit Rev Clin Lab Sci 2011; 48:19-47. [PMID: 21657944 DOI: 10.3109/10408363.2011.580567] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The brain is one of the major target organs of alcohol actions. Alcohol abuse can lead to alterations in brain structure and functions and, in some cases, to neurodegeneration. Cognitive deficits and alcohol dependence are highly damaging consequences of alcohol abuse. Clinical and experimental studies have demonstrated that the developing brain is particularly vulnerable to alcohol, and that drinking during gestation can lead to a range of physical, learning and behavioral defects (fetal alcohol spectrum disorders), with the most dramatic presentation corresponding to fetal alcohol syndrome. Recent findings also indicate that adolescence is a stage of brain maturation and that heavy drinking at this stage can have a negative impact on brain structure and functions causing important short- and long-term cognitive and behavioral consequences. The effects of alcohol on the brain are not uniform; some brain areas or cell populations are more vulnerable than others. The prefrontal cortex, the hippocampus, the cerebellum, the white matter and glial cells are particularly susceptible to the effects of ethanol. The molecular actions of alcohol on the brain are complex and involve numerous mechanisms and signaling pathways. Some of the mechanisms involved are common for the adult brain and for the developing brain, while others depend on the developmental stage. During brain ontogeny, alcohol causes irreversible alterations to the brain structure. It also impairs several molecular, neurochemical and cellular events taking place during normal brain development, including alterations in both gene expression regulation and the molecules involved in cell-cell interactions, interference with the mitogenic and growth factor response, enhancement of free radical formation and derangements of glial cell functions. However, in both adult and adolescent brains, alcohol damages specific brain areas through mechanisms involving excitotoxicity, free radical formation and neuroinflammatory damage resulting from activation of the innate immune system mediated by TLR4 receptors. Alcohol also acts on specific membrane proteins, such as neurotransmitter receptors (e.g. NMDA, GABA-A), ion channels (e.g. L-type Ca²⁺ channels, GIRKs), and signaling pathways (e.g. PKA and PKC signaling). These effects might underlie the wide variety of behavioral effects induced by ethanol drinking. The neuroadaptive changes affecting neurotransmission systems which are more sensitive to the acute effects of alcohol occur after long-term alcohol consumption. Alcohol-induced maladaptations in the dopaminergic mesolimbic system, abnormal plastic changes in the reward-related brain areas and genetic and epigenetic factors may all contribute to alcohol reinforcement and alcohol addiction. This manuscript reviews the mechanisms by which ethanol impacts the adult and the developing brain, and causes both neural impairments and cognitive and behavioral dysfunctions. The identification and the understanding of the cellular and molecular mechanisms involved in ethanol toxicity might contribute to the development of treatments and/or therapeutic agents that could reduce or eliminate the deleterious effects of alcohol on the brain.
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Abstract
Diets rich in SFA have been implicated in Alzheimer's disease (AD). There is strong evidence to suggest that microglial activation augments the progression of AD. However, it remains uncertain whether SFA can initiate microglial activation and whether this response can cause neuronal death. Using the BV-2 microglial cell line and primary microglial culture, we showed that palmitic acid (PA) and stearic acid (SA) could activate microglia, as assessed by reactive morphological changes and significantly increased secretion of pro-inflammatory cytokines, NO and reactive oxygen species, which trigger primary neuronal death. In addition, the mRNA level of these pro-inflammatory mediators determined by RT-PCR was also increased by PA and SA. We further investigated the intracellular signalling mechanism underlying the release of pro-inflammatory mediators from PA-activated microglial cells. The present results showed that PA activated the phosphorylation and nuclear translocation of the p65 subunit of NF-κB. Furthermore, pyrrolidine dithiocarbamate, a NF-κB inhibitor, attenuated the production of pro-inflammatory mediators except for IL-6 in PA-stimulated microglia. Administration of anti-Toll-like receptor (TLR)4-neutralising antibody repressed PA-induced NF-κB activation and pro-inflammatory mediator production. In conclusion, the present in vitro study demonstrates that SFA could activate microglia and stimulate the TLR4/NF-κB pathway to trigger the production of pro-inflammatory mediators, which may contribute to neuronal death.
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Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
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