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Karim S, Liaskou E, Hadley S, Youster J, Faint J, Adams DH, Lalor PF. An in vitro model of human acute ethanol exposure that incorporates CXCR3- and CXCR4-dependent recruitment of immune cells. Toxicol Sci 2013; 132:131-41. [PMID: 23300006 DOI: 10.1093/toxsci/kfs337] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Alcoholic liver disease (ALD) is one of the commonest causes of cirrhosis and liver failure in the developed world. Hepatic inflammation is the critical stage in progression of both ALD and non-ALD, but it remains difficult to study the underlying mechanisms in a human system, and current animal models do not fully recapitulate human liver disease. We developed a human tissue-based system to study lymphocyte recruitment in response to ethanol challenge. Precision-cut liver slices (PCLS) from human livers were incubated in culture, and hepatic function was determined by albumin production, 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium bromide assay, glucose uptake responses, and morphometric assessment. Responses of tissue and lymphocytes to ethanol exposure were determined by PCR, flow cytometry, histology, and lymphocyte infiltration assays. Human PCLS demonstrated appropriate upregulation of CYP2E1, ADH1α, and ADH3 in response to ethanol treatment. Ethanol also induced expression of endothelial VCAM-1 and ICAM-1, production of sICAM-1 and CXCL8, and the chemokine receptors CXCR3 and CXCR4 on CD4 and CD8 lymphocytes. CXCR3- and CXCR4-dependent migration of lymphocytes into the tissue increased significantly in response to treatment with ethanol. We have demonstrated that ethanol increases chemokine receptor expression and lymphocyte recruitment into human liver tissue, suggesting that it may operate directly to promote hepatitis in ALD. The physiological and pathophysiological responses of the PCLS to ethanol in vitro highlight the potential of this assay for dissecting the molecular mechanisms underlying human liver inflammation and as a screening tool for novel therapeutics.
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Affiliation(s)
- Sumera Karim
- Institute of Biomedical Research, University of Birmingham, Birmingham, UK
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Przybycien-Szymanska MM, Mott NN, Pak TR. Alcohol dysregulates corticotropin-releasing-hormone (CRH) promoter activity by interfering with the negative glucocorticoid response element (nGRE). PLoS One 2011; 6:e26647. [PMID: 22039522 PMCID: PMC3200354 DOI: 10.1371/journal.pone.0026647] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 09/30/2011] [Indexed: 11/19/2022] Open
Abstract
EtOH exposure in male rats increases corticotropin-releasing hormone (CRH) mRNA in the paraventricular nucleus of the hypothalamus (PVN), a brain region responsible for coordinating stress and anxiety responses. In this study we identified the molecular mechanisms involved in mediating these effects by examining the direct effects of EtOH on CRH promoter activity in a neuronal cell line derived from the PVN (IVB). In addition, we investigated the potential interactions of EtOH and glucocorticoids on the CRH promoter by concomitantly treating cells with EtOH and the glucocorticoid receptor (GR) antagonist RU486, and by sequentially deleting GR binding sites within glucocorticoid response element (GRE) on the CRH promoter. Cells were transiently transfected with a firefly luciferase reporter construct containing 2.5 kb of the rat wild type (WT) or mutated CRH promoter. Our results showed that EtOH treatment induced a biphasic response in CRH promoter activity. EtOH exposure for 0.5 h significantly decreased promoter activity compared to vehicle treated controls, whereas promoter activity was significantly increased after 2.0 h of EtOH exposure. Treatment with RU486, or deletion of the GR binding sites 1 and 2 within the GRE, abolished the EtOH-induced increase in the promoter activity, however did not affect EtOH-induced decrease in CRH promoter activity at an earlier time point. Overall, our data suggest that alcohol exposure directly regulates CRH promoter activity by interfering with the normal feedback mechanisms of glucocorticoids mediated by GR signaling at the GRE site of the CRH promoter.
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Affiliation(s)
- Magdalena M. Przybycien-Szymanska
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Natasha N. Mott
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Toni R. Pak
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, United States of America
- * E-mail:
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Boyadjieva NI, Sarkar DK. Role of microglia in ethanol's apoptotic action on hypothalamic neuronal cells in primary cultures. Alcohol Clin Exp Res 2011; 34:1835-42. [PMID: 20662807 DOI: 10.1111/j.1530-0277.2010.01271.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Microglia are the major inflammatory cells in the central nervous system and play a role in brain injuries as well as brain diseases. In this study, we determined the role of microglia in ethanol's apoptotic action on neuronal cells obtained from the mediobasal hypothalamus and maintained in primary cultures. We also tested the effect of cAMP, a signaling molecule critically involved in hypothalamic neuronal survival, on microglia-mediated ethanol's neurotoxic action. METHODS Ethanol's neurotoxic action was determined on enriched fetal mediobasal hypothalamic neuronal cells with or without microglia cells or ethanol-activated microglia-conditioned media. Ethanol's apoptotic action was determined using nucleosome assay. Microglia activation was determined using OX6 histochemistry and by measuring inflammatory cytokines secretion from microglia in cultures using enzyme-linked immunosorbent assay (ELISA). An immunoneutralization study was conducted to identify the role of a cytokine involved in ethanol's apoptotic action. RESULTS We show here that ethanol at a dose range of 50 and 100 mM induces neuronal death by an apoptotic process. Ethanol's ability to induce an apoptotic death of neurons is increased by the presence of ethanol-activated microglia-conditioned media. In the presence of ethanol, microglia showed elevated secretion of various inflammatory cytokines, of which TNF-α shows significant apoptotic action on mediobasal hypothalamic neuronal cells. Ethanol's neurotoxic action was completely prevented by cAMP. The cell-signaling molecule also prevented ethanol-activated microglial production of TNF-α. Immunoneutralization of TNF-α prevented the microglia-derived media's ability to induce neuronal death. CONCLUSIONS These results suggest that ethanol's apoptotic action on hypothalamic neuronal cells might be mediated via microglia, possibly via increased production of TNF-α. Furthermore, cAMP reduces TNF-α production from microglia to prevent ethanol's neurotoxic action.
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Affiliation(s)
- Nadka I Boyadjieva
- Endocrine Program, Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA
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4
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Sarkar DK, Kuhn P, Marano J, Chen C, Boyadjieva N. Alcohol exposure during the developmental period induces beta-endorphin neuronal death and causes alteration in the opioid control of stress axis function. Endocrinology 2007; 148:2828-34. [PMID: 17347308 DOI: 10.1210/en.2006-1606] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Proopiomelanocortin-producing neurons in the arcuate nucleus of the hypothalamus secrete beta-endorphin (beta-EP), which controls varieties of body functions including the feedback regulation of the CRH neuronal activity in the paraventricular nucleus of the hypothalamus. Whether ethanol exposure in developing rats induces beta-EP neuronal death and alters their influence on CRH neurons in vivo has not been determined. We report here that binge-like ethanol exposures in newborn rats increased the number of apoptotic beta-EP neurons in the arcuate nucleus of the hypothalamus. We also found that immediately after ethanol treatments there was a significant reduction in the expression of proopiomelanocortin and adenylyl cyclases mRNA and an increased expression of several TGF-beta1-linked apoptotic genes in beta-EP neurons isolated by laser-captured microdissection from arcuate nuclei of young rats. Several weeks after the ethanol treatment, we detected a reduction in the number of beta-EP neuronal perikarya in arcuate nuclei and in the number of beta-EP neuronal terminals in paraventricular nuclei of the hypothalamus in the treated rats. Additionally, these rats showed increased response of the hypothalamic CRH mRNA to the lipopolysaccharide challenge. The ethanol-treated animals also showed incompetent ability to respond to exogenous beta-EP to alter the lipopolysaccharide-induced CRH mRNA levels. These data suggest that ethanol exposure during the developmental period causes beta-EP neuronal death by cellular mechanisms involving the suppression of cyclic AMP production and activation of TGF-beta1-linked apoptotic signaling and produces long-term structural and functional deficiency of beta-EP neurons in the hypothalamus.
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Affiliation(s)
- Dipak K Sarkar
- Endocrinology Program, Rutgers-The State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901, USA.
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Chen CP, Kuhn P, Chaturvedi K, Boyadjieva N, Sarkar DK. Ethanol induces apoptotic death of developing beta-endorphin neurons via suppression of cyclic adenosine monophosphate production and activation of transforming growth factor-beta1-linked apoptotic signaling. Mol Pharmacol 2005; 69:706-17. [PMID: 16326933 DOI: 10.1124/mol.105.017004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanism by which ethanol induces beta-endorphin (beta-EP) neuronal death during the developmental period was determined using fetal rat hypothalamic cells in primary cultures. The addition of ethanol to hypothalamic cell cultures stimulated apoptotic cell death of beta-EP neurons by increasing caspase-3 activity. Ethanol lowered the levels of adenylyl cyclase (AC)7 mRNA, AC8 mRNA, and/or cAMP in hypothalamic cells, whereas a cAMP analog blocked the apoptotic action of ethanol on beta-EP neurons. The AC inhibitor dideoxyadenosine (DDA) increased cell apoptosis and reduced the number of beta-EP neurons, and it potentiated the apoptotic action of ethanol on these neurons. beta-EP neurons in hypothalamic cultures showed immunoreactivity to transforming growth factor-beta1 (TGF-beta1) protein. Ethanol and DDA increased TGF-beta1 production and/or release from hypothalamic cells. A cAMP analog blocked the activation by ethanol of TGF-beta1 in these cells. TGF-beta1 increased apoptosis of beta-EP neurons, but it did not potentiate the action of ethanol or DDA actions on these neurons. TGF-beta1 neutralizing antibody blocked the apoptotic action of ethanol on beta-EP neurons. Determination of TGF-beta1-controlled cell apoptosis regulatory gene levels in hypothalamic cell cultures and in isolated beta-EP neurons indicated that ethanol, TGF-beta1, and DDA similarly alter the expression of these genes in these cells. These data suggest that ethanol increases beta-EP neuronal death during the developmental period by cellular mechanisms involving, at least partly, the suppression of cAMP production and activation of TGF-beta1-linked apoptotic signaling.
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Affiliation(s)
- Cui Ping Chen
- Endocrinology Program and Department of Animal Sciences, 84 Lipman Dr., Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
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Dokur M, Chen CP, Advis JP, Sarkar DK. Beta-endorphin modulation of interferon-gamma, perforin and granzyme B levels in splenic NK cells: effects of ethanol. J Neuroimmunol 2005; 166:29-38. [PMID: 16005984 DOI: 10.1016/j.jneuroim.2005.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Accepted: 03/14/2005] [Indexed: 11/25/2022]
Abstract
The effects of ethanol and beta-endorphin (beta-EP) on productions of cytolytic factors granzyme B, perforin and IFN-gamma in splenic rat NK cells were determined. Intracranial administration of beta-EP increased protein and mRNA levels of cytolytic factors in NK cells. Chronic ethanol feeding reduced the basal and beta-EP-induced levels of cytolytic factors in NK cells. In vitro treatment of beta-EP on NK cells increased the levels of perforin, granzyme B and IFN-gamma and their mRNA transcripts, whereas ethanol pre-treatment prevented beta-EP effects on cytolytic factors in these cells. These results suggest that beta-EP and ethanol interact to regulate NK cell functions.
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Affiliation(s)
- Madhavi Dokur
- Endocrine Program, Biomedical Division of the Center of Alcohol Studies and Department of Animal Sciences, Rutgers, The State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901-8525, USA
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Li Z, Kang SS, Lee S, Rivier C. Effect of ethanol on the regulation of corticotropin-releasing factor (CRF) gene expression. Mol Cell Neurosci 2005; 29:345-54. [PMID: 15914027 DOI: 10.1016/j.mcn.2005.04.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Revised: 02/09/2005] [Accepted: 04/06/2005] [Indexed: 11/20/2022] Open
Abstract
Ethanol stimulates hypothalamic-pituitary-adrenal axis activity in vivo. To determine the cellular and molecular mechanisms through which ethanol regulates corticotropin-releasing factor (CRF) gene expression, we compared the effect of ethanol and forskolin on CRF peptide secretion and messenger RNA levels in hypothalamic primary cell cultures, and on CRF promoter activity in the NG108-15 cell line. CRF secretion, mRNA levels, and gene transcription significantly increased in response to ethanol or forskolin. Mutation of the cAMP-response element (CRE) reduced luciferase activity under basal conditions as well as in response to forskolin or ethanol. On the other hand, plasmid with five CRE repeats yielded dramatically elevated basal luciferase activity and significantly increased upregulation by ethanol. Inclusion of adenosine deaminase reduced the promoter response to ethanol. Finally a PKA inhibitor and a cAMP antagonist both decreased ethanol-induced CRF peptide secretion, gene expression, and transcription. These results suggest that ethanol upregulates CRF expression through cAMP/PKA-dependent pathways.
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Affiliation(s)
- Zhongqi Li
- The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
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Zalewska-Kaszubska J, Czarnecka E. Deficit in beta-endorphin peptide and tendency to alcohol abuse. Peptides 2005; 26:701-5. [PMID: 15752586 DOI: 10.1016/j.peptides.2004.11.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 11/09/2004] [Accepted: 11/10/2004] [Indexed: 11/24/2022]
Abstract
Human and animal studies suggest that there is a correlation between endogenous opioid peptides, especially beta-endorphin, and alcohol abuse. It has been proven that the consumption of alcohol activates the endogenous opioid system. Consumption of alcohol results in an increase in beta-endorphin level in those regions of the human brain, which are associated with a reward system. However, it has also been observed that habitual alcohol consumption leads to a beta-endorphin deficiency. It is a well-documented phenomenon that people with a genetic deficit of beta-endorphin peptide are particularly susceptible to alcoholism. The plasma level of beta-endorphin in subjects genetically at high risk of excessive alcohol consumption shows lower basal activity of this peptide. Its release increases significantly after alcohol consumption. Clinical and laboratory studies confirm that certain genetically determined factors might increase the individual's vulnerability to alcohol abuse.
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Boyadjieva NI, Chen CP, Sarkar DK. Role of nitric oxide in alcohol alteration of beta-endorphin release from hypothalamic cells in primary cultures. Alcohol Clin Exp Res 2004; 27:1813-8. [PMID: 14634498 DOI: 10.1097/01.alc.0000093740.63754.0c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Nitric oxide (NO) mediates many pharmacological actions of ethanol. NO's role in regulating ethanol action on hypothalamic beta-endorphin (beta-EP) neurons is not established. METHODS In this study, we determined the role of NO in ethanol regulation of beta-EP release from primary cultures of rat fetal mediobasal hypothalamic cells. Real-time polymerase chain reaction was used for messenger RNA (mRNA) detection; radioimmunoassay was used for hormone measurements. RESULTS Acute ethanol treatment for 3 hr increased the release of beta-EP but reduced nitrite levels in the media of hypothalamic cells in primary cultures. In contrast, ethanol exposure for 48 hr reduced the release of beta-EP but increased the release of nitrite from these cells. Alcohol treatments altered the expression of neuronal NO synthase mRNA, but not inducible NO synthase mRNA, in a pattern similar to that of nitrite levels. Alcohol treatments blocked sodium nitroprusside-induced increases in the level of cellular cyclic guanidine monophosphate. The nonspecific NO blocker NG-nitro-l-arginine-methyl-esther, but not the inactive isomer N-nitro-d-arginine-methyl-esther (d-NAME), inhibited ethanol inhibitory actions on beta-EP release. CONCLUSIONS These results suggest that the cyclic guanidine monophosphate/NO pathway is involved in ethanol alteration of hypothalamic beta-EP release.
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Affiliation(s)
- Nadka I Boyadjieva
- Center for Alcohol Studies and Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick 08901-8525, USA
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10
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Abstract
Although far from conclusive, evidence implicating the endogenous opioid system in the development and maintenance of alcoholism is growing. Currently available data suggest that ethanol increases opioid neurotransmission and that this activation is part of the mechanism responsible for its reinforcing effects. Findings from preclinical research indicate that ethanol consumption and ethanol-induced dopamine (DA) release are both reduced by opioid antagonists. Individual differences in endogenous opioid activity have been linked to inherited risks for alcoholism in studies comparing ethanol-preferring and nonpreferring rats, as well as in studies using targeted gene mutation (knockout) strategies. To a large extent, findings from human studies have paralleled those from the preclinical work. Persons who differ in family history of alcoholism have been shown to also differ in basal beta-endorphin activity, beta-endorphin response to alcohol, and subjective and HPA axis hormonal response to opioid antagonists. Findings from clinical trials indicate that opioid antagonists may reduce ethanol consumption in alcoholics, particularly in persons who have resumed drinking. Nevertheless, many questions remain unanswered about the use of opioid antagonists in alcoholism treatment and about the exact role of the opioid system in ethanol preference and reward. The progression of knowledge in this field suggests that many of these questions are imminently answerable, as our ability to characterize relationships between opioid activity and human behavior continues to develop. This paper summarizes both the progress that has been made and the gaps that remain in our understanding of the interactions between the endogenous opioid system and risk for alcoholism.
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Affiliation(s)
- L M Oswald
- Departments of Medicine and Psychiatry, The Johns Hopkins University, School of Medicine, Ross Research Building, Room 863, 720 Rutland Avenue, Baltimore, MD 21205, USA
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Liu X, Zha J, Nishitani J, Chen H, Zack JA. HIV-1 infection in peripheral blood lymphocytes (PBLs) exposed to alcohol. Virology 2003; 307:37-44. [PMID: 12667812 DOI: 10.1016/s0042-6822(02)00031-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Epidemiological and in vitro studies have implied that heavy alcohol consumption may increase an individual's risk of HIV-1 infection. To examine the role of alcohol in direct infection of T-cells, viral reverse transcripts and HIV-1 receptor expression were examined in infected peripheral blood lymphocytes (PBLs) pretreated with alcohol. PCR results showed that alcohol increased HIV-1 DNA in PBLs by at least 10-fold. Alcohol enhanced the expression of the CXCR4 chemokine co-receptor but not the major HIV-1 CD4 receptor. Pretreatment with alcohol was also associated with increased intracellular cAMP. Thus, alcohol may facilitate enhanced viral infection by increasing the availability of HIV-1 co-receptor. This effect is associated with increases in intracellular cAMP.
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Affiliation(s)
- Xuan Liu
- Department of Oral & Maxillofacial Surgery, Charles R. Drew University of Medicine & Science, Hawkins Building, Room 3067, 1731 East 120th Street, Los Angeles, CA 90059, USA.
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Yao L, Arolfo MP, Dohrman DP, Jiang Z, Fan P, Fuchs S, Janak PH, Gordon AS, Diamond I. betagamma Dimers mediate synergy of dopamine D2 and adenosine A2 receptor-stimulated PKA signaling and regulate ethanol consumption. Cell 2002; 109:733-43. [PMID: 12086672 DOI: 10.1016/s0092-8674(02)00763-8] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Dopamine release is activated by ethanol and addicting drugs, but molecular mechanisms linking dopaminergic signaling to neuronal responses and drinking behavior are poorly understood. We report that dopamine-D2 receptors induce PKA Calpha translocation and increase CRE-regulated gene expression. Ethanol also activates PKA signaling. Subthreshold concentrations of the D2 agonist NPA and ethanol, without effect alone, together cause synergistic PKA translocation and CRE-mediated gene transcription. D2 or adenosine A2 receptor blockade, pertussis toxin, Rp-cAMPS, or overexpression of dominant-negative peptides that sequester betagamma dimers prevent synergy. Importantly, overexpression of a betagamma inhibitor peptide in the nucleus accumbens strikingly reduces sustained alcohol consumption. We propose that synergy of D2 and A2 confers ethanol hypersensitivity and that betagamma dimers are required for voluntary drinking.
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MESH Headings
- Adenoviridae/genetics
- Alcohol Drinking
- Animals
- Animals, Newborn
- Apomorphine/analogs & derivatives
- Apomorphine/pharmacology
- Blotting, Western
- Cyclic AMP/metabolism
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Dimerization
- Dopamine Agonists/pharmacology
- Dose-Response Relationship, Drug
- Ethanol/pharmacology
- G1 Phase
- Gene Expression Regulation
- Genes, Reporter
- Hippocampus/cytology
- Immunohistochemistry
- Integrases/metabolism
- Isoenzymes/metabolism
- Luciferases/metabolism
- Microscopy, Confocal
- Models, Biological
- Peptides/chemistry
- Pertussis Toxin
- Protein Binding
- Protein Kinase C/metabolism
- Protein Kinase C-alpha
- Protein Structure, Tertiary
- Protein Transport
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D2/chemistry
- Receptors, Dopamine D2/metabolism
- Receptors, Purinergic P1/chemistry
- Receptors, Purinergic P1/metabolism
- Signal Transduction
- Subcellular Fractions
- Time Factors
- Transcription, Genetic
- Transfection
- Viral Proteins/metabolism
- Virulence Factors, Bordetella/pharmacology
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Affiliation(s)
- Lina Yao
- Ernest Gallo Clinic and Research Center, San Francisco, CA 94110, USA
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De A, Boyadjieva N, Sarkar DK. Role of protein kinase C in control of ethanol-modulated beta-endorphin release from hypothalamic neurons in primary cultures. J Pharmacol Exp Ther 2002; 301:119-28. [PMID: 11907165 DOI: 10.1124/jpet.301.1.119] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have previously shown that short-term exposure to ethanol stimulates immunoreactive beta-endorphin (IR-beta-EP) release from hypothalamic neurons and that chronic ethanol exposure decreases the IR-beta-EP release from these neurons. The role of protein kinase C (PKC) in the ethanol-regulated beta-EP release from hypothalamic neurons has not been established. In this study, by using the primary cultures of hypothalamic neurons, we tested the effects of PKC stimulator phorbol ester 4 beta-phorbol 12-myristate-13-acetate (PMA) and PKC inhibitor chelerythrine chloride on ethanol-induced IR-beta-EP release. Additionally, the effects of ethanol with or without PMA on expression and translocation of various PKC isoenzymes from cytosolic to membrane fraction were determined. PMA treatment increased IR-beta-EP release in a time- and dose-dependent manner. Acute ethanol treatment (3 h) increased, while chronic ethanol treatment (24 h) reduced, the magnitude of PMA-induced IR-beta-EP release. The stimulatory effect of acute ethanol on IR-beta-EP release was reduced by chelerythrine chloride. Determination of the effects of ethanol with or without PMA on seven different PKC isoenzymes (PKC-alpha, -beta I, -beta II, -gamma, -delta, -epsilon, and -zeta) revealed that the expression and translocation of only two PKC isoenzymes, PKC-delta and PKC-epsilon, were stimulated by acute treatment with ethanol. Acute ethanol also increased PMA-stimulated expression of these two isoenzymes. Chronic ethanol treatment reduced both basal and PMA-induced increase of PKC-delta and PKC-epsilon expression and translocation. These data provide evidence for the first time that ethanol-regulated IR-beta-EP secretion is controlled by the PKC system, possibly involving PKC-delta and PKC-epsilon isoenzymes.
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Affiliation(s)
- Alok De
- Department of Animal Sciences, Rutgers, The State University of New Jersey, Cook College, New Brunswick, New Jersey 08901-8525, USA
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