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Petersen OH. Different Effects of Alcohol on the Liver and the Pancreas. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab008. [PMID: 35330811 PMCID: PMC8788802 DOI: 10.1093/function/zqab008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/12/2021] [Accepted: 02/12/2021] [Indexed: 01/06/2023]
Affiliation(s)
- Ole H Petersen
- School of Biosciences, Cardiff University, Wales, UK,Corresponding author: E-mail:
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2
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Gaspers LD, Thomas AP, Hoek JB, Bartlett PJ. Ethanol Disrupts Hormone-Induced Calcium Signaling in Liver. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab002. [PMID: 33604575 PMCID: PMC7875097 DOI: 10.1093/function/zqab002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/22/2020] [Accepted: 12/30/2020] [Indexed: 01/06/2023]
Abstract
Receptor-coupled phospholipase C (PLC) is an important target for the actions of ethanol. In the ex vivo perfused rat liver, concentrations of ethanol >100 mM were required to induce a rise in cytosolic calcium (Ca2+) suggesting that these responses may only occur after binge ethanol consumption. Conversely, pharmacologically achievable concentrations of ethanol (≤30 mM) decreased the frequency and magnitude of hormone-stimulated cytosolic and nuclear Ca2+ oscillations and the parallel translocation of protein kinase C-β to the membrane. Ethanol also inhibited gap junction communication resulting in the loss of coordinated and spatially organized intercellular Ca2+ waves in hepatic lobules. Increasing the hormone concentration overcame the effects of ethanol on the frequency of Ca2+ oscillations and amplitude of the individual Ca2+ transients; however, the Ca2+ responses in the intact liver remained disorganized at the intercellular level, suggesting that gap junctions were still inhibited. Pretreating hepatocytes with an alcohol dehydrogenase inhibitor suppressed the effects of ethanol on hormone-induced Ca2+ increases, whereas inhibiting aldehyde dehydrogenase potentiated the inhibitory actions of ethanol, suggesting that acetaldehyde is the underlying mediator. Acute ethanol intoxication inhibited the rate of rise and the magnitude of hormone-stimulated production of inositol 1,4,5-trisphosphate (IP3), but had no effect on the size of Ca2+ spikes induced by photolysis of caged IP3. These findings suggest that ethanol inhibits PLC activity, but does not affect IP3 receptor function. We propose that by suppressing hormone-stimulated PLC activity, ethanol interferes with the dynamic modulation of [IP3] that is required to generate large, amplitude Ca2+ oscillations.
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Affiliation(s)
- Lawrence D Gaspers
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA,Address correspondence to L.D.G. (e-mail: )
| | - Andrew P Thomas
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Jan B Hoek
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Paula J Bartlett
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
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Leroy K, Pieters A, Tabernilla A, Cooreman A, Van Campenhout R, Cogliati B, Vinken M. Targeting gap junctional intercellular communication by hepatocarcinogenic compounds. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2020; 23:255-275. [PMID: 32568623 DOI: 10.1080/10937404.2020.1781010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Gap junctions in liver, as in other organs, play a critical role in tissue homeostasis. Inherently, these cellular constituents are major targets for systemic toxicity and diseases, including cancer. This review provides an overview of chemicals that compromise liver gap junctions, in particular biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. The focus in this review is placed upon the mechanistic scenarios that underlie these adverse effects. Further, the potential use of gap junctional activity as an in vitro biomarker to identify non-genotoxic hepatocarcinogenic chemicals is discussed.
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Affiliation(s)
- Kaat Leroy
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Alanah Pieters
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Andrés Tabernilla
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Axelle Cooreman
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Raf Van Campenhout
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Cidade Universitária , São Paulo, Brazil
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , Brussels, Belgium
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Bartlett PJ, Antony AN, Agarwal A, Hilly M, Prince VL, Combettes L, Hoek JB, Gaspers LD. Chronic alcohol feeding potentiates hormone-induced calcium signalling in hepatocytes. J Physiol 2017; 595:3143-3164. [PMID: 28220501 DOI: 10.1113/jp273891] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 01/26/2017] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Chronic alcohol consumption causes a spectrum of liver diseases, but the pathogenic mechanisms driving the onset and progression of disease are not clearly defined. We show that chronic alcohol feeding sensitizes rat hepatocytes to Ca2+ -mobilizing hormones resulting in a leftward shift in the concentration-response relationship and the transition from oscillatory to more sustained and prolonged Ca2+ increases. Our data demonstrate that alcohol-dependent adaptation in the Ca2+ signalling pathway occurs at the level of hormone-induced inositol 1,4,5 trisphosphate (IP3 ) production and does not involve changes in the sensitivity of the IP3 receptor or size of internal Ca2+ stores. We suggest that prolonged and aberrant hormone-evoked Ca2+ increases may stimulate the production of mitochondrial reactive oxygen species and contribute to alcohol-induced hepatocyte injury. ABSTRACT: 'Adaptive' responses of the liver to chronic alcohol consumption may underlie the development of cell and tissue injury. Alcohol administration can perturb multiple signalling pathways including phosphoinositide-dependent cytosolic calcium ([Ca2+ ]i ) increases, which can adversely affect mitochondrial Ca2+ levels, reactive oxygen species production and energy metabolism. Our data indicate that chronic alcohol feeding induces a leftward shift in the dose-response for Ca2+ -mobilizing hormones resulting in more sustained and prolonged [Ca2+ ]i increases in both cultured hepatocytes and hepatocytes within the intact perfused liver. Ca2+ increases were initiated at lower hormone concentrations, and intercellular calcium wave propagation rates were faster in alcoholics compared to controls. Acute alcohol treatment (25 mm) completely inhibited hormone-induced calcium increases in control livers, but not after chronic alcohol-feeding, suggesting desensitization to the inhibitory actions of ethanol. Hormone-induced inositol 1,4,5 trisphosphate (IP3 ) accumulation and phospholipase C (PLC) activity were significantly potentiated in hepatocytes from alcohol-fed rats compared to controls. Removal of extracellular calcium, or chelation of intracellular calcium did not normalize the differences in hormone-stimulated PLC activity, indicating calcium-dependent PLCs are not upregulated by alcohol. We propose that the liver 'adapts' to chronic alcohol exposure by increasing hormone-dependent IP3 formation, leading to aberrant calcium increases, which may contribute to hepatocyte injury.
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Affiliation(s)
- Paula J Bartlett
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
| | - Anil Noronha Antony
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Amit Agarwal
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
| | - Mauricette Hilly
- INSERM UMR-S 757, Université de Paris-Sud, bât 443, 91405, Orsay, France
| | - Victoria L Prince
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
| | - Laurent Combettes
- INSERM UMR-S 757, Université de Paris-Sud, bât 443, 91405, Orsay, France
| | - Jan B Hoek
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Lawrence D Gaspers
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA
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Do THT, Gaboriau F, Cannie I, Batusanski F, Ropert M, Moirand R, Brissot P, Loreal O, Lescoat G. Iron-mediated effect of alcohol on hepatocyte differentiation in HepaRG cells. Chem Biol Interact 2013; 206:117-25. [PMID: 24025710 DOI: 10.1016/j.cbi.2013.08.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 08/19/2013] [Accepted: 08/30/2013] [Indexed: 01/16/2023]
Abstract
The development of alcoholic liver diseases depends on the ability of hepatocyte to proliferate and differentiate in the case of alcohol-induced injury. Our previous work showed an inhibitory effect of alcohol on hepatocyte proliferation. However, the effect of alcohol on hepatocyte differentiation has not yet been precisely characterized. In the present study, we evaluated the effect of alcohol on hepatocyte differentiation in relationship with changes of iron metabolism in HepaRG cells. This unique bipotent human cell line can differentiate into hepatocytes and biliary epithelial cells, paralleling liver development. Results showed that alcohol reduced cell viability, total protein level and enhanced hepatic enzymes leakage in differentiated HepaRG cells. Moreover, it caused cell enlargement, decreased number of hepatocyte and expression of C/EBPα as well as bile canaliculi F-actin. Alcohol increased expression of hepatic cell-specific markers and alcohol-metabolizing enzymes (ADH2, CYP2E1). This was associated with a lipid peroxidation and an iron excess expressed by an increase in total iron content, ferritin level, iron uptake as well as an overexpression of genes involved in iron transport and storage. Alcohol-induced hepatoxicity was amplified by exogenous iron via exceeding iron overload. Taken together, our data demonstrate that in differentiated hepatocytes, alcohol reduces proliferation while increasing expression of hepatic cell-specific markers. Moreover, iron overload could be one of the underlying mechanisms of effect of alcohol on the whole differentiation process of hepatocytes.
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Affiliation(s)
- Thi Hong Tuoi Do
- Inserm, UMR 991, «Foie, Métabolismes et Cancer», F-35033 Rennes, France; Université de Rennes 1, F-35043 Rennes, France; University of Medicine and Pharmacy at Ho Chi Minh City, Viet Nam.
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Abstract
The distal airways are covered with a heterogeneous layer of cells known as the alveolar epithelium. Alveolar epithelial cells provide the major barrier between the airspace and fluid filled tissue compartments. As such, regulation of the alveolar epithelium is critical to maintain a healthy lung and for optimal gas exchange. In this chapter, we discuss functional roles for alveolar epithelial cells with particular emphasis on intercellular junctions and communication. As a thin layer of cells directly exposed to atmospheric oxygen, alveoli are particularly sensitive to oxidant insults. Alcohol significantly diminishes the normal antioxidant reserves of the alveolar epithelium, thereby rendering it sensitized for an exaggerated damage response to acute and chronic injuries. The effects of alcohol on alveolar epithelia are discussed along with open questions and potential therapeutic targets to prevent the pathophysiology of alcoholic lung disease.
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Vinken M, Doktorova T, Decrock E, Leybaert L, Vanhaecke T, Rogiers V. Gap junctional intercellular communication as a target for liver toxicity and carcinogenicity. Crit Rev Biochem Mol Biol 2009; 44:201-22. [PMID: 19635038 DOI: 10.1080/10409230903061215] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Direct communication between hepatocytes, mediated by gap junctions, constitutes a major regulatory platform in the control of liver homeostasis, ranging from hepatocellular proliferation to hepatocyte cell death. Inherent to this pivotal task, gap junction functionality is frequently disrupted upon impairment of the homeostatic balance, as occurs during liver toxicity and carcinogenicity. In the present paper, the deleterious effects of a number of chemical and biological toxic compounds on hepatic gap junctions are discussed, including environmental pollutants, biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. Particular attention is paid to the molecular mechanisms that underlie the abrogation of gap junction functionality. Since hepatic gap junctions are specifically targeted by tumor promoters and epigenetic carcinogens, both in vivo and in vitro, inhibition of gap junction functionality is considered as a suitable indicator for the detection of nongenotoxic hepatocarcinogenicity.
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Affiliation(s)
- Mathieu Vinken
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
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Johnson LN, Koval M. Cross-talk between pulmonary injury, oxidant stress, and gap junctional communication. Antioxid Redox Signal 2009; 11:355-67. [PMID: 18816185 PMCID: PMC2933150 DOI: 10.1089/ars.2008.2183] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Gap junction channels interconnect several different types of cells in the lung, ranging from the alveolar epithelium to the pulmonary vasculature, each of which expresses a unique subset of gap junction proteins (connexins). Major lung functions regulated by gap junctional communication include coordination of ciliary beat frequency and inflammation. Gap junctions help enable the alveolus to regulate surfactant secretion as an integrated system, in which type I cells act as mechanical sensors that transmit calcium transients to type II cells. Thus, disruption of epithelial gap junctional communication, particularly during acute lung injury, can interfere with these processes and increase the severity of injury. Consistent with this, connexin expression is altered during lung injury, and connexin-deficiency has a negative impact on the injury response and lung-growth control. It has recently been shown that alcohol abuse is a significant risk factor associated with acute respiratory distress syndrome. Oxidant stress and hormone-signaling cascades in the lung induced by prolonged alcohol ingestion are discussed, as well as the effects of these pathways on connexin expression and function.
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Affiliation(s)
- Latoya N Johnson
- Division of Pulmonary, Allergy and Critical Care Medicine, and Emory Alcohol and Lung Biology Center, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Wentlandt K, Kushnir M, Naus CCG, Carlen PL. Ethanol inhibits gap-junctional coupling between P19 cells. Alcohol Clin Exp Res 2004; 28:1284-90. [PMID: 15365297 DOI: 10.1097/01.alc.0000139705.17646.ba] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Gap junctions are plaques of multiple intercellular channels that connect the cytoplasm of adjacent cells. They provide both electrical and metabolic coupling and are an essential element in normal growth, development, and physiology. Little research exists on the relationship between alcohol administration and gap-junctional function or expression. This study looks at the function and expression of gap junctions after incubation and withdrawal of ethanol with P19 cell cultures. METHODS Gap-junctional communication was assessed after 24 and 48 hr of exposure to 20 and 40 mM ethanol and after a 24-hr withdrawal period. The seeding technique was used, and diacyl-3,3'-indocarbocyanine iodide/calcein-stained donor cells were seeded on an unstained monolayer and then reviewed by confocal microscope and counted by flow cytometry. Analysis of connexin (Cx) proteins was performed by Western blot, gel electrophoresis, and immunoblots with antibodies for Cx26 and Cx43. RESULTS All treatment regimens produced similar results, reducing dye coupling by more than 50% without recovery after a 24-hr withdrawal period. Exposing the cells to 20 mM ethanol for 48 hr did not significantly change the levels of Cx26 protein, but ethanol significantly decreased the levels of Cx43 in cultured P19 cells. CONCLUSIONS This study illustrates that ethanol can inhibit gap-junction function in the P19 cell line. Chronic exposure to 20 mM ethanol selectively decreased the levels of Cx43 protein in the membrane fraction of the cell cultures.
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Affiliation(s)
- Kirsten Wentlandt
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
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Adermark L, Olsson T, Hansson E. Ethanol acutely decreases astroglial gap junction permeability in primary cultures from defined brain regions. Neurochem Int 2004; 45:971-8. [PMID: 15337295 DOI: 10.1016/j.neuint.2004.06.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Revised: 03/15/2004] [Accepted: 06/21/2004] [Indexed: 11/21/2022]
Abstract
The acute effect of hyperosmotic ethanol on gap junction permeability was examined in astroglial cells in primary culture from five different brain regions. Gap junction permeability was analyzed by measuring dye spreading from cell to cell with the low molecular weight dye Lucifer Yellow. Ethanol concentrations 25-300 mM significantly decreased dye spreading in cultures from the cerebral cortex in a dose-dependent but time-independent manner for up to 60 min. Besides cerebral cortex, exposure to 150 mM ethanol decreased dye spreading in astroglial cultures from the hippocampus and from the brain stem, while cultures from the olfactory bulb and from the hypothalamus were not significantly affected. The ethanol-induced decrease in dye spreading in cultures from the cerebral cortex was not mediated through changes in cell volume, osmolarity, protein kinase C (PKC) phosphorylation, intracellular pH, or intracellular calcium concentration ([Ca(2+)](i)). The decrease in dye spreading was abolished upon incubation in sodium-reduced buffer, and after blockage of the Na(+)/K(+)/2Cl(-) cotransporter with furosemide. The results presented here indicate that ethanol-mediated decrease in dye spreading is directly or indirectly dependent on sodium.
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Affiliation(s)
- Louise Adermark
- Institute of Clinical Neuroscience, Göteborg University, Box 420, SE 405 30 Göteborg, Sweden.
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Schaffert CS, Todero SL, McVicker BL, Tuma PL, Sorrell MF, Tuma DJ. WIF-B cells as a model for alcohol-induced hepatocyte injury. Biochem Pharmacol 2004; 67:2167-74. [PMID: 15135311 DOI: 10.1016/j.bcp.2004.01.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2004] [Accepted: 01/27/2004] [Indexed: 11/30/2022]
Abstract
A potential in vitro model for studying the mechanisms of alcohol-induced hepatocyte injury is the WIF-B cell line. It has many hepatocyte-like features, including a differentiated, polarized phenotype resulting in formation of bile canaliculi. The aim of this study was to examine the effects of ethanol treatment on this cell line. WIF-B cells were cultured up to 96 h in the absence or presence of 25 mM ethanol and subsequently were analyzed for ethanol-induced physiological and morphological changes. Initial studies revealed WIF-B cells exhibited alcohol dehydrogenase (ADH) activity, expressed cytochrome p4502E1 (CYP2E1), and efficiently metabolized ethanol in culture. This cell line also produced the ethanol metabolite acetaldehyde and exhibited low K(m) aldehyde dehydrogenase (ALDH) activity, comparable to hepatocytes. Ethanol treatment of the WIF-B cells for 48 h led to significant increases in the lactate/pyruvate redox ratio and cellular triglyceride levels. Ethanol treatment also significantly altered WIF-B morphology, decreasing the number of bile canaliculi, increasing the number of cells exhibiting finger-like projections, and increasing cell diameter. The ethanol-induced changes occurring in this cell line were negated by addition of the ADH inhibitor, 4-methylpyrazole (4-MP), indicating the effects were due to ethanol metabolism. In summary, the WIF-B cell line metabolizes ethanol and exhibits many ethanol-induced changes similar to those found in hepatocytes. Because of these similarities, WIF-B cells appear to be a suitable model for studying ethanol-induced hepatocyte injury.
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Affiliation(s)
- Courtney S Schaffert
- The Department of Veterans Affairs Medical Center, University of Nebraska Medical Center, Omaha, NE, USA
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Bokkala S, Reis HM, Rubin E, Joseph SK. Effect of angiotensin II and ethanol on the expression of connexin 43 in WB rat liver epithelial cells. Biochem J 2001; 357:769-77. [PMID: 11463347 PMCID: PMC1222006 DOI: 10.1042/0264-6021:3570769] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The turnover of connexin 43 (Cx43) is very rapid in many cells and involves both the lysosomal and proteasomal protease pathways. Here we show that Ca(2+)-mobilizing agonists such as angiotensin II (Ang II) can up-regulate the expression of Cx43 in WB rat liver epithelial cells. Vasopressin had the same effect in A7R5 smooth-muscle cells. The effect of Ang II was not prevented by pretreatment with proteasomal or lysosomal inhibitors and was associated with an enhanced biosynthesis of Cx43 as measured by metabolic labelling experiments. The accumulation of Cx43 occurred in intracellular compartments and at the cell surface, as determined by confocal immunofluorescence studies and by immunoblotting of fractions soluble and insoluble in Triton X-100. Chronic treatment of WB cells with ethanol inhibited Cx43 expression; this was associated with decreased biosynthesis of Cx43. Neither treatment with Ang II nor treatment with ethanol altered the levels of Cx43 mRNA. Incubation of WB cells with Ang II did not alter gap-junctional communication as judged by a dye-coupling assay. However, treatment with ethanol markedly decreased gap-junctional communication and this effect was diminished in Ang-II-treated cells, demonstrating that gap-junctional communication is linked to the level of Cx43 expression. We conclude that Cx43 biosynthesis is regulated by Ca(2+)-mobilizing agonists and ethanol in WB cells. The changes in Cx43 expression might have a role in modifying the conduction of metabolites and second messengers between cells.
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Affiliation(s)
- S Bokkala
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
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Oviedo-Orta E, Gasque P, Evans WH. Immunoglobulin and cytokine expression in mixed lymphocyte cultures is reduced by disruption of gap junction intercellular communication. FASEB J 2001; 15:768-74. [PMID: 11259395 DOI: 10.1096/fj.00-0288com] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Connexins (Cx), the protein subunits assembled into gap junction intercellular communication channels, are expressed in primary lymphoid organs and by circulating leukocytes. Human tonsil-derived T and B lymphocytes express Cx40 and 43; circulating human T, B, and NK lymphocytes express Cx43 and directly transfer between each other a low molecular dye indicative that functional gap junctions exist. We now identify specific properties in the immune system underwritten by gap junctions. Mixed lymphocytes cultured in the presence of two reagents with independent inhibitory action on gap junction communication, a connexin mimetic peptide and 18-alpha-glycyrrhetinic acid, markedly reduced the secretion of IgM, IgG, and IgA. The secretion of these immunoglobulins by purified B cells was also reduced by the two classes of gap junction inhibitors. Complex temporal inhibitory effects on the expression of mRNA encoding interleukins, especially IL-10, were also observed. The results indicate that intercellular signaling across gap junctions is an important component of the mechanisms underlying metabolic cooperation in the immune system.
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Affiliation(s)
- E Oviedo-Orta
- University of Wales College of Medicine, Department of Medical Biochemistry, Wales Heart Research Institute, Heath Park, Cardiff CF14 4XN, Wales, U.K.
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