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Rico EP, Rosemberg DB, Berteli JFA, da Silveira Langoni A, Souto AA, Bogo MR, Bonan CD, Souza DO. Adenosine deaminase activity and gene expression patterns are altered after chronic ethanol exposure in zebrafish brain. Neurotoxicol Teratol 2017; 65:14-18. [PMID: 29122710 DOI: 10.1016/j.ntt.2017.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 11/01/2017] [Accepted: 11/05/2017] [Indexed: 11/28/2022]
Abstract
Ethanol alters the homeostasis between excitatory and inhibitory neurotransmitters and its intoxication reveals adenosine as responsible to modify several responses including signal transduction. Zebrafish has been recently investigated for knowledge the prolonged effect of ethanol on behavioral and biochemical parameters. The aim of this study was to evaluate the soluble and membrane adenosine deaminase activities and gene expression in zebrafish brain. Animals were exposed to 0.5% ethanol for 7, 14, and 28days. There were no significant changes in ADA activity from soluble fraction after all treatments. However, we verified a decrease of ADA activity in membrane fraction after 28days (44%) of ethanol exposure. ADA1 was not altered whereas mRNA transcript levels for ADAL presented an increase after 28days of ethanol exposure (34%). ADA2-1 showed a decrease (26%) followed by an increase (17%) of transcripts after 14 and 28days of ethanol exposure, respectively. However, ADA2-1 truncated alternative splice isoform (ADA2-1/T) demonstrated a reduction after 28days (20%). ADA2-2 was decreased (22%) followed by an increase (109%) of transcripts after 14 and 18days of ethanol exposure, respectively. Altogether, the purine catabolism promoted by ADA may be an important target of the chronic toxicity induced for ethanol.
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Affiliation(s)
- Eduardo Pacheco Rico
- Programa de Pós-Graduação em Ciências da Saúde, Laboratório de Sinalização Neural e Psicofarmacologia, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Bloco S, Sala 6, Bairro Universitário, Criciúma, SC, Brazil; Instituto Nacional de Ciência e Tecnologia em Excitotoxicidade e Neuroproteção (INCT-EN), 90035-003 Porto Alegre, RS, Brazil.
| | - Denis Broock Rosemberg
- Programa de Pós-Graduação em Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, RS, 97105-900 Santa Maria, RS, Brazil; Instituto Nacional de Ciência e Tecnologia em Excitotoxicidade e Neuroproteção (INCT-EN), 90035-003 Porto Alegre, RS, Brazil
| | - Jotele Fontana Agostini Berteli
- Programa de Pós-Graduação em Ciências da Saúde, Laboratório de Sinalização Neural e Psicofarmacologia, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Bloco S, Sala 6, Bairro Universitário, Criciúma, SC, Brazil
| | - Andrei da Silveira Langoni
- Programa de Pós-Graduação em Biologia Celular e Molecular, Laboratório de Neuroquímica e Psicofarmacologia, Brazil
| | - André Arigony Souto
- Faculdade de Química, Pontifícia Universidade Católica do Rio Grande do Sul. Avenida Ipiranga, 6681, 90619-900 Porto Alegre, RS, Brazil
| | - Maurício Reis Bogo
- Laboratório de Biologia Genômica e Molecular, Departamento de Biologia Celular e Molecular, Brazil; Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), 90035-003 Porto Alegre, RS, Brazil
| | - Carla Denise Bonan
- Programa de Pós-Graduação em Biologia Celular e Molecular, Laboratório de Neuroquímica e Psicofarmacologia, Brazil; Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), 90035-003 Porto Alegre, RS, Brazil
| | - Diogo Onofre Souza
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul. Rua Ramiro Barcelos 2600-Anexo, 90035-003 Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia em Excitotoxicidade e Neuroproteção (INCT-EN), 90035-003 Porto Alegre, RS, Brazil
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Kouzoukas DE, Li G, Takapoo M, Moninger T, Bhalla RC, Pantazis NJ. Intracellular calcium plays a critical role in the alcohol-mediated death of cerebellar granule neurons. J Neurochem 2012; 124:323-35. [PMID: 23121601 DOI: 10.1111/jnc.12076] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 09/30/2012] [Accepted: 10/10/2012] [Indexed: 11/28/2022]
Abstract
Alcohol is a potent neuroteratogen that can trigger neuronal death in the developing brain. However, the mechanism underlying this alcohol-induced neuronal death is not fully understood. Utilizing primary cultures of cerebellar granule neurons (CGN), we tested the hypothesis that the alcohol-induced increase in intracellular calcium [Ca(2+)](i) causes the death of CGN. Alcohol induced a dose-dependent (200-800 mg/dL) neuronal death within 24 h. Ratiometric Ca(2+) imaging with Fura-2 revealed that alcohol causes a rapid (1-2 min), dose-dependent increase in [Ca(2+)](i), which persisted for the duration of the experiment (5 or 7 min). The alcohol-induced increase in [Ca(2+)](i) was observed in Ca(2+) -free media, suggesting intracellular Ca(2+) release. Pre-treatment of CGN cultures with an inhibitor (2-APB) of the inositol-triphosphate receptor (IP(3) R), which regulates Ca(2+) release from the endoplasmic reticulum (ER), blocked both the alcohol-induced rise in [Ca(2+)](i) and the neuronal death caused by alcohol. Similarly, pre-treatment with BAPTA/AM, a Ca(2+) -chelator, also inhibited the alcohol-induced surge in [Ca(2+) ](i) and prevented neuronal death. In conclusion, alcohol disrupts [Ca(2+)](i) homeostasis in CGN by releasing Ca(2+) from intracellular stores, resulting in a sustained increase in [Ca(2+)](i). This sustained increase in [Ca(2+)](i) may be a key determinant in the mechanism underlying alcohol-induced neuronal death.
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Affiliation(s)
- Dimitrios E Kouzoukas
- Department of Anatomy and Cell Biology, Carver College of Medicine, The University of Iowa, Iowa City, IA, USA
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Aho L, Karkola K, Juusela J, Alafuzoff I. Heavy alcohol consumption and neuropathological lesions: a post-mortem human study. J Neurosci Res 2010; 87:2786-92. [PMID: 19382227 DOI: 10.1002/jnr.22091] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Epidemiological studies have indicated that excessive alcohol consumption leads to cognitive impairment, but the specific pathological mechanism involved remains unknown. The present study evaluated the association between heavy alcohol intake and the neuropathological hallmark lesions of the three most common neurodegenerative disorders, i.e., Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and vascular cognitive impairment (VCI), in post-mortem human brains. The study cohort was sampled from the subjects who underwent a medicolegal autopsy during a 6-month period in 1999 and it included 54 heavy alcohol consumers and 54 age- and gender-matched control subjects. Immunohistochemical methodology was used to visualize the aggregation of beta-amyloid, hyperphosphorylated tau, and alpha-synuclein and the extent of infarcts. In the present study, no statistically significant influence was observed for alcohol consumption on the extent of neuropathological lesions encountered in the three most common degenerative disorders. Our results indicate that alcohol-related dementia differs from VCI, AD, and DLB; i.e., it has a different etiology and pathogenesis.
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Affiliation(s)
- Leena Aho
- Department of Clinical Medicine, Unit of Neurology, Kuopio University, Kuopio, Finland
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Torres LM, Cefaratti C, Berti-Mattera L, Romani A. Delayed restoration of Mg2+ content and transport in liver cells following ethanol withdrawal. Am J Physiol Gastrointest Liver Physiol 2009; 297:G621-31. [PMID: 19556361 PMCID: PMC2763811 DOI: 10.1152/ajpgi.90652.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Liver cells from rats chronically fed a Lieber-De Carli diet for 3 wk presented a marked decreased in tissue Mg(2+) content and an inability to extrude Mg(2+) into the extracellular compartment upon stimulation with catecholamine, isoproterenol, or cell-permeant cAMP analogs. This defect in Mg(2+) extrusion was observed in both intact cells and purified liver plasma membrane vesicles. Inhibition of adrenergic or cAMP-mediated Mg(2+) extrusion was also observed in freshly isolated hepatocytes from control rats incubated acutely in vitro with varying doses of ethanol (EtOH) for 8 min. In this model, however, the defect in Mg(2+) extrusion was observed in intact cells but not in plasma membrane vesicles. In the chronic model, upon removal of EtOH from the diet hepatic Mg(2+) content and extrusion required approximately 10 days to return to normal level both in isolated cells and plasma membrane vesicles. In hepatocytes acutely treated with EtOH for 8 min, more than 60 min were necessary for Mg(2+) content and extrusion to recover and return to the level observed in EtOH-untreated cells. Taken together, these data suggest that in the acute model the defect in Mg(2+) extrusion is the result of a limited refilling of the cellular compartment(s) from which Mg(2+) is mobilized upon adrenergic stimulation rather than a mere defect in adrenergic cellular signaling. The chronic EtOH model, instead, presents a transient but selective defect of the Mg(2+) extrusion mechanisms in addition to the limited refilling of the cellular compartments.
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Ward RJ, Lallemand F, de Witte P. Biochemical and neurotransmitter changes implicated in alcohol-induced brain damage in chronic or 'binge drinking' alcohol abuse. Alcohol Alcohol 2009; 44:128-35. [PMID: 19155229 DOI: 10.1093/alcalc/agn100] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The brain damage, which occurs after either chronic alcoholization or binge drinking regimes, shows distinct biochemical and neurotransmitter differences. An excessive amount of glutamate is released into specific brain regions during binge drinking (in excess of 4- to 5-fold of the normal basal concentration) that is not evident during periods of excessive alcohol consumption in chronic alcohol abusers. Increases in glutamate release are only observed during the initial stages of withdrawal from chronic alcoholism ( approximately 2- to 3-fold) due to alterations in the sensitivities of the NMDA receptors. Such changes in either density or sensitivity of these receptors are reported to be unaltered by binge drinking. When such excesses of glutamate are released in these two different models of alcohol abuse, a wide range of biochemical changes occur, mediated in part by increased fluxes of calcium ions and/or activation of various G-protein-associated signalling pathways. Cellular studies of alveolar macrophages isolated from these two animal models of alcohol abuse showed enhanced (binge drinking) or reduced (chronic alcoholization) lipopolysaccharide (LPS)-stimulated NO release. Such studies could suggest that neuroadaptation occurs with the development of tolerance to alcohol's effects in both neurotransmitter function and cellular processes during chronic alcoholization that delay the occurrence of brain damage. In contrast, 'binge drinking' induces immediate and toxic effects and there is no evidence of an increased preference for alcohol as seen after withdrawal from chronic alcoholization.
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Affiliation(s)
- Roberta J Ward
- Biologie du Comportement, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
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Gerlai R, Ahmad F, Prajapati S. Differences in acute alcohol-induced behavioral responses among zebrafish populations. Alcohol Clin Exp Res 2008; 32:1763-73. [PMID: 18652595 DOI: 10.1111/j.1530-0277.2008.00761.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND With the arsenal of genetic tools available for zebrafish, this species has been successfully used to investigate the genetic aspects of human diseases from developmental disorders to cancer. Interest in the behavior and brain function of zebrafish is also increasing as CNS disorders may be modeled and studied with this species. Alcoholism and alcohol abuse are among the most devastating and costliest diseases. However, the mechanisms of these diseases are not fully understood. Zebrafish has been proposed as a model organism to study such mechanisms. Characterization of alcohol's effects on zebrafish is a necessary step in this research. METHODS Here, we compare the effects of acute alcohol (EtOH) administration on the behavior of zebrafish from 4 distinct laboratory-bred populations using automated as well as observation based behavioral quantification methods. RESULTS Alcohol treatment resulted in significant dose-dependent behavioral changes but the dose-response trajectories differed among zebrafish populations. CONCLUSIONS The results demonstrate for the first time a genetic component in alcohol responses in adult zebrafish and also show the feasibility of high throughput behavioral screening. We discuss the exploration and exploitation of the genetic differences found.
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Affiliation(s)
- Robert Gerlai
- Department of Psychology, University of Toronto, Mississauga, Ontario, Canada.
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Kanbak G, Arslan OC, Dokumacioglu A, Kartkaya K, Inal ME. Effects of Chronic Ethanol Consumption on Brain Synaptosomes and Protective Role of Betaine. Neurochem Res 2007; 33:539-44. [PMID: 17763942 DOI: 10.1007/s11064-007-9472-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Accepted: 08/06/2007] [Indexed: 11/30/2022]
Abstract
To evaluate the cytotoxic effects of chronic ethanol consumption on brain cerebral synaptosomes and preventive role of betaine as a methyl donor and S-adenosylmethionine precursor, 24 male Wistar rats were divided into three groups: control, ethanol (8 g/kg/day) and ethanol plus betaine(0.5% w/v) group. Animals were fed 60 ml/diet per day for two months, then sacrificed. Malondialdehyde (MDA), protein carbonyl contents and adenosine deaminase (ADA) activities were determined in synaptosomal/mitochondrial enriched fraction isolated from rat cerebral cortexes. When compared to controls, ethanol containing diet significantly increased MDA levels (P < 0.05), also increased protein carbonyl levels and adenosine deaminase activities. But these were not statistically significant (P > 0.05). However, adding betaine to ethanol containing diet caused a significant decrease in MDA, protein carbonyl levels and adenosine deaminase activities (P < 0.05). These results indicate that betaine may appear as a protective nutritional agent against cytotoxic brain damage induced by chronic ethanol consumption.
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Affiliation(s)
- Gungor Kanbak
- Department of Biochemistry, School of Medicine, Eskisehir Osmangazi University, Eskisehir 26480, Turkey
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Lee YJ, Shukla SD. Histone H3 phosphorylation at serine 10 and serine 28 is mediated by p38 MAPK in rat hepatocytes exposed to ethanol and acetaldehyde. Eur J Pharmacol 2007; 573:29-38. [PMID: 17643407 PMCID: PMC2723821 DOI: 10.1016/j.ejphar.2007.06.049] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2006] [Revised: 06/26/2007] [Accepted: 06/26/2007] [Indexed: 01/10/2023]
Abstract
Ethanol modulates mitogen-activated protein kinases (MAPKs). We have now investigated the influence of ethanol and its metabolite, acetaldehyde on histone H3 phosphorylation to ascertain downstream targets of MAPKs. In primary culture of rat hepatocytes, ethanol and acetaldehyde increased phosphorylation of nuclear histone H3 at serine 10 and serine 28. Specific inhibitors of p38 MAPK, SB203580, PD169316 and SB202190 blocked this phosphorylation. The inactive analogue, SB202474 had no effect. In contrast, c-Jun N-terminal kinase (JNK) inhibitor, SP600125 or MAP/ERK kinase (MEK) 1/2 inhibitor, PD98059 had no effect on the histone H3 phosphorylation. The p38 MAPK activation correlated with upstream activation of MAPK kinase (MKK) 3/6 but was independent of protein synthesis. In the nuclear fraction, the phosphorylation of p38 MAPK and its protein level increased with peak activation at 24 h by ethanol and at 30 min by acetaldehyde. These responses were ethanol and acetaldehyde dose dependent. Surprisingly, the phosphorylation of p38 MAPK was undetectable in the cytosolic fraction suggesting a subcellular selectivity of p38 MAPK signaling. The phosphorylation of JNK and p42/44 MAPK and their protein levels also increased in the nuclear fraction. Although ethanol caused translocation of all three major MAPKs (p42/44 MAPK, JNK, p38 MAPK) into the nucleus, histone H3 phosphorylation at serine 10 and serine 28 was mediated by p38 MAPK. This histone H3 phosphorylation had no influence on ethanol and acetaldehyde induced apoptosis. These studies demonstrate for the first time that ethanol and acetaldehyde stimulated phosphorylation of histone H3 at serine 10 and serine 28 are downstream nuclear response mediated by p38 MAPK in hepatocytes.
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Affiliation(s)
| | - Shivendra D. Shukla
- Corresponding author: Shivendra D. Shukla, Department of Medical Pharmacology & Physiology, School of medicine, University of Missouri-Columbia, One hospital Drive, M526 Medical Science Building, Columbia, MO 65212, Tel: (573) 882-2740, Fax: (573) 884-4276, E-mail:
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Lehmann DM, Galloway CA, MacElrevey C, Sowden MP, Wedekind JE, Smith HC. Functional characterization of APOBEC-1 complementation factor phosphorylation sites. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1773:408-18. [PMID: 17229474 PMCID: PMC1847399 DOI: 10.1016/j.bbamcr.2006.11.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Revised: 11/13/2006] [Accepted: 11/27/2006] [Indexed: 11/17/2022]
Abstract
ApoB mRNA editing involves site-specific deamination of cytidine 6666 producing an in-frame translation stop codon. Editing minimally requires APOBEC-1 and APOBEC-1 complementation factor (ACF). Metabolic stimulation of apoB mRNA editing in hepatocytes is associated with serine phosphorylation of ACF localized to editing competent, nuclear 27S editosomes. We demonstrate that activation of protein kinase C (PKC) stimulated editing and enhanced ACF phosphorylation in rat primary hepatocytes. Conversely, activation of protein kinase A (PKA) had no effect on editing. Recombinant PKC efficiently phosphorylated purified ACF64 protein in vitro, whereas PKA did not. Mutagenesis of predicted PKC phosphorylation sites S154 and S368 to alanine inhibited ethanol-stimulated induction of editing suggesting that these sites function in the metabolic regulation of editing. Consistent with this interpretation, substitution of S154 and S368 with aspartic acid stimulated editing to levels comparable to ethanol treatment in control McArdle RH7777 cells. These data suggest that phosphorylation of ACF by PKC may be a key regulatory mechanism of apoB mRNA editing in rat hepatocytes.
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Affiliation(s)
- David M. Lehmann
- Department of Toxicology, University of Rochester, Rochester, New York 14642
- Environmental Health Sciences Center, University of Rochester, Rochester, New York 14642
| | - Chad A. Galloway
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642
| | - Celeste MacElrevey
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642
| | - Mark P. Sowden
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642
- Department of Pathology and Laboratory Medicine, University of Rochester, Rochester, New York 14642
| | - Joseph E. Wedekind
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642
| | - Harold C. Smith
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642
- Department of Pathology and Laboratory Medicine, University of Rochester, Rochester, New York 14642
- Department of Toxicology, University of Rochester, Rochester, New York 14642
- Environmental Health Sciences Center, University of Rochester, Rochester, New York 14642
- James P. Wilmot Cancer Center, University of Rochester, Rochester, New York 14642
- * Corresponding author: Department of Biochemistry and Biophysics, University of Rochester, 601 Elmwood Ave., Rochester, NY 14642 Tel.: 585-275-4267 FAX: 585-275-6007 E-mail:
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Schaffert CS, Todero SL, Casey CA, Thiele GM, Sorrell MF, Tuma DJ. Chronic ethanol treatment impairs Rac and Cdc42 activation in rat hepatocytes. Alcohol Clin Exp Res 2006; 30:1208-13. [PMID: 16792569 DOI: 10.1111/j.1530-0277.2006.00135.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The effects of chronic ethanol feeding on rat hepatocytes have been shown to include impaired cell-extracellular matrix (ECM) adhesion events, such as decreased attachment and spreading as well as increased integrin-actin cytoskeleton association. These results, observed previously by this laboratory, are highly suggestive of impaired actin cytoskeleton reorganization, an event mediated by differential activation of the Rho family GTPases Rac, Cdc42, and RhoA. Therefore, the purpose of this study was to examine the effects of chronic ethanol administration on these GTPases. METHODS Male Wistar rats were pair-fed 4 to 5 weeks with a liquid diet containing either ethanol (as 36% of total calories) or isocaloric carbohydrate. Hepatocytes were isolated and plated on collagen IV up to 24 hours. At specific times, the hepatocytes were lysed and these lysates were analyzed for RhoA, Cdc42, and Rac activation. RESULTS In freshly isolated hepatocytes from ethanol-fed rats, the GTP-bound (active) forms of Rac and Cdc42 were significantly decreased compared with pair-fed control rats, while the GTP-bound form of RhoA was not significantly altered. These ethanol-induced impairments in Rac and Cdc42 activation persisted even after plating the hepatocytes on collagen IV. Additionally, chronic ethanol treatment did not directly affect GTP binding of Cdc42 and Rac, as incorporation of GTPgammaS was not affected. CONCLUSIONS Chronic ethanol administration selectively impairs Rac and Cdc42 activation in rat hepatocytes. As activation of these 2 GTPases is crucial for efficient cell attachment and spreading on ECM substrates, the results from this study suggest that the ethanol-induced impairments in Rac and Cdc42 activation are responsible for the impaired hepatocyte-ECM adhesion events observed previously by our laboratory. Furthermore, these results raise the intriguing possibility that these GTPases are involved in other ethanol-induced functional impairments, such as protein trafficking and receptor-mediated endocytosis.
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Choi DK, Lee H, Jeong J, Lim B, Suk K. Differential effects of ethanol on glial signal transduction initiated by lipopolysaccharide and interferon-gamma. J Neurosci Res 2006; 82:225-31. [PMID: 16175582 DOI: 10.1002/jnr.20647] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although the pathogenic effects of alcohol abuse on brain are well established, its specific effects on the intracellular signal transduction pathways of glial cells in the central nervous system (CNS) are poorly understood. In this study, we evaluated how ethanol affects the glial signal transduction associated with inflammatory activation. Lipopolysaccharide (LPS), gangliosides, and interferon (IFN)-gamma induced the inflammatory activation of glia, which was differentially influenced by ethanol: 1) ethanol inhibited LPS- or gangliosides-induced, but not IFNgamma-induced, glial activation as demonstrated by the production of nitric oxide and the expression of inflammatory genes such as interleukin-1beta, tumor necrosis factor-alpha, IP-10, and CD86; 2) nuclear factor (NF)-kappaB or JAK/STAT1 pathway was necessary for LPS- or IFNgamma-induced glial activation, respectively; 3) ethanol inhibited LPS-induced NF-kappaB activation; and 4) ethanol did not significantly affect IFNgamma-induced STAT1/IRF-1 activation. Based on these results, ethanol seems to inhibit selectively some parts of the glial signal transduction pathways that are associated with inflammatory activation, which may lead to the deregulation of CNS inflammatory responses.
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Affiliation(s)
- Dong-Kug Choi
- Department of Biotechnology, Konkuk University, Chungju, Korea
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Lee H, Jeong J, Son E, Mosa A, Cho GJ, Choi WS, Ha JH, Kim IK, Lee MG, Kim CY, Suk K. Ethanol selectively modulates inflammatory activation signaling of brain microglia. J Neuroimmunol 2004; 156:88-95. [PMID: 15465599 DOI: 10.1016/j.jneuroim.2004.07.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Revised: 07/16/2004] [Accepted: 07/19/2004] [Indexed: 11/19/2022]
Abstract
In spite of well-known deleterious effects of alcohol on the nervous system in general, its specific effect on the brain immune system remains poorly understood. In order to better understand the effect of alcohol consumption on the innate immunity and inflammatory responses in the central nervous system (CNS), we sought to determine how ethanol influences inflammatory activation of microglia that function as the resident immune defense system of the brain. After treatment of BV-2 mouse microglial cells or rat primary microglia cultures with various stimuli, nitric oxide (NO) production was measured as an indicator of microglial activation. Pretreatment of the cells with ethanol (10-100 mM) for 1 h resulted in a significant decrease in lipopolysaccharide (LPS)-induced, but not interferon-gamma (IFNgamma)-induced, NO production, indicating that ethanol specifically inhibits LPS-induced inflammatory activation of microglia. This was further supported by the ethanol inhibition of LPS-induced IL-1beta expression. In addition, ethanol pretreatment selectively regulated LPS-induced NF-kappaB signaling pathway without affecting IFNgamma-induced signal transducer and activator of transcription 1 (STAT1) phosphorylation, interferon regulatory factor-1 (IRF-1) induction or IFNgamma-inducible IP-10 expression. The modulation of LPS-induced NF-kappaB by ethanol was due to the inhibition of coactivator p300. Altogether, these results suggest that acute ethanol exposure may selectively modulate signal transduction pathways associated with inflammatory activation of microglia, which may lead to derangement of CNS immune and inflammatory responses.
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Affiliation(s)
- Heasuk Lee
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, #101 Dong-In, Joong-gu, Daegu 700-422, Republic of Korea
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Buckley CT, Sekiya F, Kim YJ, Rhee SG, Caldwell KK. Identification of Phospholipase C-γ1 as a Mitogen-activated Protein Kinase Substrate. J Biol Chem 2004; 279:41807-14. [PMID: 15258148 DOI: 10.1074/jbc.m407851200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The discovery of sequence motifs that mediate protein-protein interactions, coupled with the availability of protein amino acid sequence data, allows for the identification of putative protein binding pairs. The present studies were based on our identification of an amino acid sequence in phosphatidylinositol-specific phospholipase C-gamma1 (PLC-gamma1) that fits the consensus sequence for a mitogen-activated protein kinase (MAPK) binding site, termed the D-domain. Extracellular signal-regulated kinase 2 (ERK2), an MAPK, and phospho-ERK2 were bound by an immobilized peptide sequence containing the identified PLC-gamma1 D-domain. Furthermore, a peptide containing the PLC-gamma1 D-domain was able to competitively inhibit the in vitro phosphorylation of recombinant PLC-gamma1 by recombinant phospho-ERK2, whereas a control peptide derived from a distant region of PLC-gamma1 was ineffective. Similarly, the peptide containing the PLC-gamma1 D-domain, but not the control peptide, competitively inhibited the in vitro phosphorylation of Elk-1 and c-Jun catalyzed by recombinant phospho-ERK2 and phospho-c-Jun N-terminal kinase 3 (phospho-JNK3), another type of MAPK, respectively. Incubation of anti-PLC-gamma1 immunocomplexes isolated from rat brain with recombinant phospho-ERK2 opposed the increase in PLC-gamma1-catalyzed hydrolysis of phosphatidylinositol 4,5-P(2) (PtdIns(4,5)P(2)), which was produced by a tyrosine kinase associated with the immunocomplexes, whereas in vitro phosphorylation of recombinant PLC-gamma1 by recombinant phospho-ERK2 did not alter PLC-gamma1-catalyzed PtdIns(4,5)P(2) hydrolysis. These studies have uncovered a previously unidentified mechanism for the integration of PLC-gamma1- and ERK2-dependent signaling.
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Affiliation(s)
- Colin T Buckley
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA
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Abstract
Alcoholic hepatitis is a potentially life-threatening complication of alcoholic abuse, typically presenting with symptoms and signs of hepatitis in the presence of an alcohol use disorder. The definitive diagnosis requires liver biopsy, but this is not generally required. The pathogenesis is uncertain, but relevant factors include metabolism of alcohol to toxic products, oxidant stress, acetaldehyde adducts, the action of endotoxin on Kupffer cells, and impaired hepatic regeneration. Mild alcoholic hepatitis recovers with abstinence and the long-term prognosis is determined by the underlying disorder of alcohol use. Severe alcoholic hepatitis is recognized by a Maddrey discriminant function >32 and is associated with a short-term mortality rate of almost 50%. Primary therapy is abstinence from alcohol and supportive care. Corticosteroids have been shown to be beneficial in a subset of severely ill patients with concomitant hepatic encephalopathy, but their use remains controversial. Pentoxifylline has been shown in one study to improve short-term survival rates. Other pharmacological interventions, including colchicine, propylthiouracil, calcium channel antagonists, and insulin with glucagon infusions, have not been proven to be beneficial. Nutritional supplementation with available high-calorie, high-protein diets is beneficial, but does not improve mortality. Orthotopic liver transplantation is not indicated for patients presenting with alcoholic hepatitis who have been drinking until the time of admission, but may be considered in those who achieve stable abstinence if liver function fails to recover.
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Affiliation(s)
- Paul S Haber
- Drug Health Services and AW Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, and Department of Medicine, University of Sydney, Sydney, Australia.
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15
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Abstract
Activation of zymogens within the pancreatic acinar cell is an early feature of acute pancreatitis. Supraphysiologic concentrations of cholecystokinin (CCK) cause intrapancreatic zymogen activation and pancreatitis. Supraphysiologic concentrations of CCK also cause zymogen activation in isolated pancreatic acini. This activation first occurs in a nonzymogen granule compartment that contains lysosomal markers. A low pH environment may also be needed for activation. To examine the ability of alcohols to sensitize the acinar cell to CCK, the conversion of zymogens to active enzymes in isolated acini was assayed. Alcohols, including 35 mmol/L ethanol, sensitized acini to CCK induced activation. The sensitization increased with chain length and was less in branched compared with unbranched alcohols. The relationship of alcohol's structure to sensitization may be related to the mechanism of sensitization.
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Affiliation(s)
- Fred S Gorelick
- Department of Internal Medicine (Section of Digestive Diseases), VA Connecticut Healthcare, West Haven and Yale University School of Medicine, New Haven, Connecticut, USA.
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Debelak-Kragtorp KA, Armant DR, Smith SM. Ethanol-induced cephalic apoptosis requires phospholipase C-dependent intracellular calcium signaling. Alcohol Clin Exp Res 2003; 27:515-23. [PMID: 12658119 DOI: 10.1097/01.alc.0000056615.34253.a8] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Although the ability of ethanol to elicit neural crest cell apoptosis is well documented, the initial target of ethanol in these cells, and the biochemical pathway leading to their apoptosis, have yet to be determined. Recent work in preimplantation mouse embryos demonstrates that ethanol induces a phospholipase-C (PLC)-dependent calcium transient that mediates ethanol's effects. We tested whether a similar effect on calcium and PLC is involved in ethanol-induced neural crest apoptosis. METHODS Chicken embryos were collected and loaded with Fluo-3-AM to assess the effects of ethanol on intracellular calcium levels. Pharmacological agents were used to determine the sources and mechanism of intracellular calcium increases. In separate experiments, embryos were treated in ovo with pharmacological modulators of calcium signaling prior to ethanol exposure, and resulting levels of cell death were assessed by using the vital dye acridine orange. RESULTS Ethanol exposure caused a localized increase in intracellular calcium levels in embryonic neural folds within 15 sec of ethanol exposure. Ethanol-induced apoptosis was specifically blocked by chelation of intracellular calcium before ethanol exposure. Pretreatment with the PLC inhibitor U73122 blocked ethanol-induced apoptosis as well as the intracellular calcium transient. Depletion of extracellular calcium resulted in a partial block of ethanol-induced apoptosis. CONCLUSIONS Ethanol exposure alters calcium signaling within the neurulation-stage chicken embryo in a PLC-dependent manner. Increases in intracellular calcium and PLC activity are necessary for ethanol's induction of apoptosis within cephalic populations. These effects likely represent an early and crucial event in the pathway leading to ethanol-induced cell death.
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Matsumoto H, Sato Y, Azumi J, Kato J, Niitsu Y, Tamaki K. Role of Endotoxin in NF-kappaB Activation by Ethanol in Rat Hepatocytes. Alcohol Clin Exp Res 2002. [DOI: 10.1111/j.1530-0277.2002.tb02694.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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He DY, Vagts AJ, Yaka R, Ron D. Ethanol induces gene expression via nuclear compartmentalization of receptor for activated C kinase 1. Mol Pharmacol 2002; 62:272-80. [PMID: 12130678 DOI: 10.1124/mol.62.2.272] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Scaffolding proteins such as receptor for activated C kinase (RACK) 1 are involved in the targeting of signaling proteins and play an important role in the regulation of signal transduction cascades. Recently, we found that in cultured cells and in vivo, acute ethanol exposure induces the nuclear compartmentalization of RACK1. To elucidate a physiological role for nuclear RACK1, the Tat protein transduction system was used to transduce RACK1 and RACK1-derived fragments into C6 glioma cells. We found that nuclear RACK1 is mediating the induction of the immediate early gene c-fos expression induced by ethanol. First, transduction of full-length RACK1 (Tat-RACK1) resulted in the induction of c-fos expression and enhancement of ethanol activities. Second, we determined that the C terminus of RACK1 (Tat-RACK1DeltaN) is mediating transcription. Third, we identified a dominant negative fragment of RACK1 that inhibited the nuclear compartmentalization of endogenous RACK1 and inhibited ethanol-induction of c-fos mRNA and protein expression. Last, acute exposure to ethanol or transduction of full-length Tat-RACK1 resulted in an increase in mRNA levels of an activator protein 1 site-containing gene, PAC1 (pituitary adenylate cyclase-activating polypeptide receptor type I), suggesting that nuclear RACK1 is involved in the regulation of the expression of genes that are altered upon acute ethanol treatment. These results may therefore have important implications for the study of alcohol addiction.
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Affiliation(s)
- Dao-Yao He
- Ernest Gallo Research Center, Emeryville, California, USA
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20
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Simonyi A, Woods D, Sun AY, Sun GY. Grape Polyphenols Inhibit Chronic Ethanol-Induced COX-2 mRNA Expression in Rat Brain. Alcohol Clin Exp Res 2002. [DOI: 10.1111/j.1530-0277.2002.tb02545.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Weeber EJ, Savage DD, Sutherland RJ, Caldwell KK. Fear conditioning-induced alterations of phospholipase C-beta1a protein level and enzyme activity in rat hippocampal formation and medial frontal cortex. Neurobiol Learn Mem 2001; 76:151-82. [PMID: 11502147 DOI: 10.1006/nlme.2000.3994] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the effects of one-trial fear conditioning on phospholipase C-beta1a catalytic activity and protein level in hippocampal formation and medial frontal cortex of untreated control rats and rats prenatally exposed to ethanol. One hour following fear conditioning of untreated control rats, phospholipase C-beta1a protein level was increased in the hippocampal cytosolic fraction and decreased in the hippocampal membrane and cortical cytosolic and cortical membrane fractions. Twenty-four hours after fear conditioning, phospholipase C-beta1a protein level was reduced in the hippocampal cytosolic fraction and elevated in the cortical nuclear fraction; in addition, 24 h after conditioning, phospholipase C-beta1a activity in the cortical cytosolic fraction was increased. Rats that were exposed prenatally to ethanol displayed attenuated contextual fear conditioning, whereas conditioning to the acoustic-conditioned stimulus was not different from controls. In behavioral control (unconditioned) rats, fetal ethanol exposure was associated with reduced phospholipase C-beta1a enzyme activity in the hippocampal nuclear, cortical cytosolic, and cortical membrane fractions and increased phospholipase C-beta1a protein level in the hippocampal membrane and cortical cytosolic fractions. In certain cases, prenatal ethanol exposure modified the relationship between fear conditioning and changes in phospholipase C-beta1a protein level and/or activity. The majority of these effects occurred 1 h, rather than 24 h, after fear conditioning. Multivariate analysis of variance revealed interactions between fear conditioning, subcellular fraction, and prenatal ethanol exposure for measures of phospholipase C-beta1a protein level in hippocampal formation and phospholipase C-beta1a enzyme activity in medial frontal cortex. In the majority of cases, fear conditioning-induced changes in hippocampal phospholipase C-beta1a protein level were augmented in rats prenatally exposed to ethanol. In contrast, fear conditioning-induced changes in cortical phospholipase C-beta1a activity were, often, in opposite directions in prenatal ethanol-exposed compared to diet control rats. We speculate that alterations in subcellular phospholipase C-beta1a catalytic activity and protein level contribute to contextual fear conditioning and that learning deficits observed in rats exposed prenatally to ethanol result, in part, from dysfunctions in phospholipase C-beta1a signal transduction.
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Affiliation(s)
- E J Weeber
- Department of Neurosciences, University of New Mexico, Albuquerque, New Mexico 87131-5223, USA
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22
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Hallak H, Seiler AEM, Green JS, Henderson A, Ross BN, Rubin R. Inhibition of Insulin-Like Growth Factor-I Signaling by Ethanol in Neuronal Cells. Alcohol Clin Exp Res 2001. [DOI: 10.1111/j.1530-0277.2001.tb02317.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Abstract
There is strong evidence showing that chronic and excessive ethanol consumption may enhance oxidative damage to neurons and result in cell death. Although not yet well understood, ethanol may enhance ROS production in brain through a number of pathways including increased generation of hydroxyethyl radicals, induction of CYP2E1, alteration of the cytokine signaling pathways for induction of iNOS and sPLA(2), and production of prostanoids through the PLA(2)/COX pathways. Since many neurodegenerative diseases are also associated with oxidative and inflammatory mechanisms in the brain, it would be important to find out whether chronic and excessive ethanol consumption may exacerbate the progression of these diseases. There is evidence that the polyphenolic antioxidants, especially those extracted from grape skin and seed, may protect the brain from neuronal damage due to chronic ethanol administration. Among the polyphenols from grapes, resveratrol seems to have unique antioxidant properties. The possible use of this compound as a therapeutic agent to ameliorate neurodegenerative processes should be further explored.
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Affiliation(s)
- A Y Sun
- Department of Pharmacology, University of Missouri, Columbia, MO 65212, USA.
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24
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Wang JH, Sun GY. Ethanol inhibits cytokine-induced iNOS and sPLA2 in immortalized astrocytes: evidence for posttranscriptional site of ethanol action. J Biomed Sci 2001; 8:126-33. [PMID: 11173986 DOI: 10.1007/bf02255981] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Chronic and excessive ethanol consumption is known to alter neuron and glial cell functions in the central nervous system (CNS). Astrocytes comprise the major cell type in the brain. These immune active cells are capable of responding to proinflammatory cytokines and endotoxins, which stimulate transcriptional pathways leading to induction of genes, including the inducible nitric oxide synthase (iNOS) and secretory phospholipase A2 (sPLA2). In this study, we investigate the effects of ethanol on cytokine-induced iNOS and sPLA2 in immortalized astrocytes (DITNC). When DITNC cells were exposed to ethanol (0-200 mM) for 4 h prior to subsequent stimulation with cytokines for 16 h, NO production decreased with increasing ethanol concentrations starting from 50 mM. At ethanol concentrations higher than 100 mM, ethanol also inhibited cytokine-induced sPLA2 release into the culture medium. The inhibitory effect of ethanol on NO production corresponds well with the decrease in iNOS protein and NOS enzyme activity, but not with iNOS and sPLA2 mRNA nor binding of NF-kappaB to DNA. The inhibition of cytokine-induced NO production by ethanol was also dependent on the time of ethanol exposure to the cells, but addition of acetaldehyde up to 200 microM did not elicit any changes. Taken together, these results provide evidence for a posttranscriptional mode of ethanol action on the cytokine induction pathway for NO production in astrocytes.
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Affiliation(s)
- J H Wang
- Department of Nutritional Sciences, University of Missouri, Columbia, MO 65212, USA
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25
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Wu J, Liu SL, Zhu JL, Norton PA, Nojiri S, Hoek JB, Zern MA. Roles of tissue transglutaminase in ethanol-induced inhibition of hepatocyte proliferation and alpha 1-adrenergic signal transduction. J Biol Chem 2000; 275:22213-9. [PMID: 10801782 DOI: 10.1074/jbc.m000091200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanisms by which ethanol inhibits hepatocyte proliferation have been a source of some considerable investigation. Our studies have suggested a possible role for tissue transglutaminase (tTG) in this process. Others have shown that tTG has two distinctly different functions: it catalyzes protein cross-linking, which can lead to apoptosis and enhancement of extracellular matrix stability, and it can function as a G protein (Galpha(h)). Under that circumstance, we speculated that the cross-linking activity would be decreased and that it would function to enhance hepatocyte proliferation in response to adrenergic stimulation. Ethanol treatment inhibited hepatocyte proliferation and led to enhanced tTG cross-linking activity, whereas treatment of hepatocytes with an alpha1 adrenergic agonist, phenylephrine, enhanced hepatocyte proliferation while decreasing tTG cross-linking. However, phenylephrine treatment of several hepatoma cell lines had no effect on cellular proliferation or tTG cross-linking activity, and of note, Northern blot analysis demonstrated that whereas primary hepatocytes had high levels of the alpha1beta adrenergic receptor (alpha1BAR) mRNA, the hepatoma cell lines did not have this mRNA. When the Hep G(2) cell line was stably transduced with an expression vector containing the alpha1BR cDNA, the cell line responded to phenylephrine treatment with enhanced proliferation and with decreased tTG cross-linking activity. Ethanol treatment of the alpha1BAR-transfected cells suppressed the phospholipase C-mediated signaling pathways, as detected in the phenylephrine-induced Ca(2+) response. These results suggest that phenylephrine stimulation of hepatocyte proliferation appears to be occurring through the alpha1BAR, which is known to be coupled with the tTG G protein moiety, Galpha(h), and that tTG appears to play a significant role in either enhancing or inhibiting hepatocyte proliferation, depending on its cellular location and on whether it functions as a cross-linking enzyme or a G protein.
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Affiliation(s)
- J Wu
- Department of Internal Medicine and Transplant Research Program, University of California Davis Medical Center, Sacramento, California 95817, USA
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26
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Pastorino JG, Hoek JB. Ethanol potentiates tumor necrosis factor-alpha cytotoxicity in hepatoma cells and primary rat hepatocytes by promoting induction of the mitochondrial permeability transition. Hepatology 2000; 31:1141-52. [PMID: 10796891 DOI: 10.1053/he.2000.7013] [Citation(s) in RCA: 162] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In the present study, tumor necrosis factor-alpha (TNF-alpha) cytotoxicity is shown to be potentiated by ethanol exposure in vitro in the human hepatoma cell line, HepG2, and in rat primary hepatocytes. Exposure of HepG2 cells and primary hepatocytes for 48 hours to concentrations of ethanol ranging between 50 and 100 mmol/L significantly increased TNF-alpha cytotoxicity compared with cells treated with TNF-alpha alone. The cell killing was associated with, and dependent on, the development of the mitochondrial permeability transition (MPT). Two inhibitors of MPT pore opening, cyclosporin A and bongkrekic acid, prevented TNF-alpha cytotoxicity in the presence of ethanol. In addition to inhibiting cell death caused by TNF-alpha, blockade of MPT pore opening prevented mitochondrial depolarization, cytochrome c redistribution from the mitochondria to the cytosol, caspase 3 activation, and oligonucleosomal DNA fragmentation. Unlike the potentiation of TNF-alpha cytotoxicity by the translational inhibitor cycloheximide, ethanol promoted TNF-alpha-induced cell killing by a mechanism that was independent of caspase-8 activity. HepG2 cells overexpressing cytochrome-P4502E1 were even more sensitized by ethanol to induction of the MPT by TNF-alpha and the resultant cytotoxicity than wild-type HepG2 cells. In addition, primary hepatocytes isolated from chronically ethanol-fed rats showed enhanced susceptibility to TNF-alpha cytotoxicity compared with their isocalorically matched controls. Again as with the HepG2 cells, inhibiting MPT pore opening prevented the cytotoxicity of TNF-alpha in the primary hepatocytes isolated from ethanol-fed animals.
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Affiliation(s)
- J G Pastorino
- Thomas Jefferson University, Department of Pathology, Anatomy, and Cell Biology, Philadelphia, PA 19107, USA.
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27
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Bautista AP. Impact of alcohol on the ability of Kupffer cells to produce chemokines and its role in alcoholic liver disease. J Gastroenterol Hepatol 2000; 15:349-56. [PMID: 10824877 DOI: 10.1046/j.1440-1746.2000.02174.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chemokines are implicated in the pathogenesis of alcoholic liver disease in humans and in experimental models of alcohol intoxication. The major sources of these chemokines are Kupffer cells which represent more than 80% of tissue macrophages in the body. Kupffer cells are highly responsive to the effects of ethanol, endotoxin and human immunodeficiency virus (HIV)-1 glycoprotein120. These agents, either independently or in combination, may exacerbate the production of chemokines. Chemokines are agents that are highly chemotactic to mononuclear cells and granulocytes. The levels of these chemokines in sera and tissue are elevated in patients with alcoholic hepatitis, alcoholic cirrhosis, diseased livers, viral hepatitis, and in experimental models of chronic alcohol intoxication. Alcohol-induced influx of endotoxin from the gut into the portal circulation is suggested to play an important role in the activation of Kupffer cells which leads to enhanced chemokine release. The up-regulation of chemokines during alcohol consumption is selective. During the early phase of alcoholic liver disease, C-X-C or alpha-chemokines predominate. This is also associated with neutrophilic infiltration of the liver. In the later stage, up-regulation of C-C or beta-chemokine production and migration of mononuclear cells into the liver are observed, and this may lead to liver cirrhosis. Selective up-regulation of chemokine synthesis and release may involve differential modulation of the transcription factors required for chemokine gene expression. Increased cytokine release following alcohol consumption may also regulate chemokine secretion in Kupffer cells via paracrine and autocrine mechanisms and vice versa. In addition, infection with HIV-1 may further compromise the liver to more damage. During HIV-1 infection, a pre-existing liver disease superimposed on chronic alcohol consumption may also exacerbate HIV-1 replication and lymphocytic infiltration in the liver, because of the ability of HIV-1 gp120 to stimulate chemokine production by Kupffer cells and stimulate migration of inflammatory leucocytes in the liver.
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Affiliation(s)
- A P Bautista
- Department of Physiology and National Institute on Alcohol Abuse and Alcoholism-Sponsored Alcohol Research Center, Louisiana State University Medical Center, New Orleans 70112, USA.
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