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Miguel-Hidalgo JJ. Astroglia in the Vulnerability and Maintenance of Alcohol Use Disorders. ADVANCES IN NEUROBIOLOGY 2021; 26:255-279. [PMID: 34888838 DOI: 10.1007/978-3-030-77375-5_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Changes induced in the morphology and the multiplicity of functional roles played by astrocytes in brain regions critical to the establishment and maintenance of alcohol abuse suggest that they make an important contribution to the vulnerability to alcohol use disorders. The understanding of the relevant mechanisms accounting for that contribution is complicated by the fact that alcohol itself acts directly on astrocytes altering their metabolism, gene expression, and plasticity, so that the ultimate result is a complex interaction of various cellular pathways, including intracellular calcium regulation, neuroimmune responses, and regulation of neurotransmitter and gliotransmitter release and uptake. The recent years have seen a steady increase in the characterization of several of the relevant mechanisms, but much remains to be done for a full understanding of the astrocytes' contribution to the vulnerability to alcohol dependence and abuse and for using that knowledge in designing effective therapies for AUDs.
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Affiliation(s)
- José Javier Miguel-Hidalgo
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
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2
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Cortical astrocytes regulate ethanol consumption and intoxication in mice. Neuropsychopharmacology 2021; 46:500-508. [PMID: 32464636 PMCID: PMC8027025 DOI: 10.1038/s41386-020-0721-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/18/2022]
Abstract
Astrocytes are fundamental building blocks of the central nervous system. Their dysfunction has been implicated in many psychiatric disorders, including alcohol use disorder, yet our understanding of their functional role in ethanol intoxication and consumption is very limited. Astrocytes regulate behavior through multiple intracellular signaling pathways, including G-protein coupled-receptor (GPCR)-mediated calcium signals. To test the hypothesis that GPCR-induced calcium signaling is also involved in the behavioral effects of ethanol, we expressed astrocyte-specific excitatory DREADDs in the prefrontal cortex (PFC) of mice. Activating Gq-GPCR signaling in PFC astrocytes increased drinking in ethanol-naïve mice, but not in mice with a history of ethanol drinking. In contrast, reducing calcium signaling with an astrocyte-specific calcium extruder reduced ethanol intake. Cortical astrocyte calcium signaling also altered the acute stimulatory and sedative-hypnotic effects of ethanol. Astrocyte-specific Gq-DREADD activation increased both the locomotor-activating effects of low dose ethanol and the sedative-hypnotic effects of a high dose, while reduced astrocyte calcium signaling diminished sensitivity to the hypnotic effects. In addition, we found that adenosine A1 receptors were required for astrocyte calcium activation to increase ethanol sedation. These results support integral roles for PFC astrocytes in the behavioral actions of ethanol that are due, at least in part, to adenosine receptor activation.
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Ye L, Orynbayev M, Zhu X, Lim EY, Dereddi RR, Agarwal A, Bergles DE, Bhat MA, Paukert M. Ethanol abolishes vigilance-dependent astroglia network activation in mice by inhibiting norepinephrine release. Nat Commun 2020; 11:6157. [PMID: 33268792 PMCID: PMC7710743 DOI: 10.1038/s41467-020-19475-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 10/16/2020] [Indexed: 12/17/2022] Open
Abstract
Norepinephrine adjusts sensory processing in cortical networks and gates plasticity enabling adaptive behavior. The actions of norepinephrine are profoundly altered by recreational drugs like ethanol, but the consequences of these changes on distinct targets such as astrocytes, which exhibit norepinephrine-dependent Ca2+ elevations during vigilance, are not well understood. Using in vivo two-photon imaging, we show that locomotion-induced Ca2+ elevations in mouse astroglia are profoundly inhibited by ethanol, an effect that can be reversed by enhancing norepinephrine release. Vigilance-dependent astroglial activation is abolished by deletion of α1A-adrenergic receptor from astroglia, indicating that norepinephrine acts directly on these ubiquitous glial cells. Ethanol reduces vigilance-dependent Ca2+ transients in noradrenergic terminals, but has little effect on astroglial responsiveness to norepinephrine, suggesting that ethanol suppresses their activation by inhibiting norepinephrine release. Since abolition of astroglia Ca2+ activation does not affect motor coordination, global suppression of astroglial networks may contribute to the cognitive effects of alcohol intoxication. The effects of norepinephrine on sensory processing in cortical networks are altered by recreational drugs like ethanol. The authors show that ethanol suppresses the activation of astrocytes by inhibiting norepinephrine release which may contribute to the cognitive effects of alcohol intoxication.
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Affiliation(s)
- Liang Ye
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Murat Orynbayev
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Xiangyu Zhu
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.,Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Eunice Y Lim
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Ram R Dereddi
- The Chica and Heinz Schaller Research Group, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Amit Agarwal
- The Chica and Heinz Schaller Research Group, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Johns Hopkins Kavli Neuroscience Discovery Institute, Baltimore, MD, USA
| | - Manzoor A Bhat
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Martin Paukert
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA. .,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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4
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Erickson EK, Blednov YA, Harris RA, Mayfield RD. Glial gene networks associated with alcohol dependence. Sci Rep 2019; 9:10949. [PMID: 31358844 PMCID: PMC6662804 DOI: 10.1038/s41598-019-47454-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/17/2019] [Indexed: 02/07/2023] Open
Abstract
Chronic alcohol abuse alters the molecular structure and function of brain cells. Recent work suggests adaptations made by glial cells, such as astrocytes and microglia, regulate physiological and behavioral changes associated with addiction. Defining how alcohol dependence alters the transcriptome of different cell types is critical for developing the mechanistic hypotheses necessary for a nuanced understanding of cellular signaling in the alcohol-dependent brain. We performed RNA-sequencing on total homogenate and glial cell populations isolated from mouse prefrontal cortex (PFC) following chronic intermittent ethanol vapor exposure (CIE). Compared with total homogenate, we observed unique and robust gene expression changes in astrocytes and microglia in response to CIE. Gene co-expression network analysis revealed biological pathways and hub genes associated with CIE in astrocytes and microglia that may regulate alcohol-dependent phenotypes. Astrocyte identity and synaptic calcium signaling genes were enriched in alcohol-associated astrocyte networks, while TGF-β signaling and inflammatory response genes were disrupted by CIE treatment in microglia gene networks. Genes related to innate immune signaling, specifically interferon pathways, were consistently up-regulated across CIE-exposed astrocytes, microglia, and total homogenate PFC tissue. This study illuminates the cell-specific effects of chronic alcohol exposure and provides novel molecular targets for studying alcohol dependence.
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Affiliation(s)
- Emma K Erickson
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712-01095, USA.
| | - Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712-01095, USA
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712-01095, USA
| | - R Dayne Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712-01095, USA
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Erickson EK, Grantham EK, Warden AS, Harris RA. Neuroimmune signaling in alcohol use disorder. Pharmacol Biochem Behav 2018; 177:34-60. [PMID: 30590091 DOI: 10.1016/j.pbb.2018.12.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/25/2018] [Accepted: 12/20/2018] [Indexed: 02/07/2023]
Abstract
Alcohol use disorder (AUD) is a widespread disease with limited treatment options. Targeting the neuroimmune system is a new avenue for developing or repurposing effective pharmacotherapies. Alcohol modulates innate immune signaling in different cell types in the brain by altering gene expression and the molecular pathways that regulate neuroinflammation. Chronic alcohol abuse may cause an imbalance in neuroimmune function, resulting in prolonged perturbations in brain function. Likewise, manipulating the neuroimmune system may change alcohol-related behaviors. Psychiatric disorders that are comorbid with AUD, such as post-traumatic stress disorder, major depressive disorder, and other substance use disorders, may also have underlying neuroimmune mechanisms; current evidence suggests that convergent immune pathways may be involved in AUD and in these comorbid disorders. In this review, we provide an overview of major neuroimmune cell-types and pathways involved in mediating alcohol behaviors, discuss potential mechanisms of alcohol-induced neuroimmune activation, and present recent clinical evidence for candidate immune-related drugs to treat AUD.
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Affiliation(s)
- Emma K Erickson
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712-01095, USA.
| | - Emily K Grantham
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712-01095, USA
| | - Anna S Warden
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712-01095, USA
| | - R A Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712-01095, USA
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Adermark L, Bowers MS. Disentangling the Role of Astrocytes in Alcohol Use Disorder. Alcohol Clin Exp Res 2016; 40:1802-16. [PMID: 27476876 PMCID: PMC5407469 DOI: 10.1111/acer.13168] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 07/02/2016] [Indexed: 01/29/2023]
Abstract
Several laboratories recently identified that astrocytes are critical regulators of addiction machinery. It is now known that astrocyte pathology is a common feature of ethanol (EtOH) exposure in both humans and animal models, as even brief EtOH exposure is sufficient to elicit long-lasting perturbations in astrocyte gene expression, activity, and proliferation. Astrocytes were also recently shown to modulate the motivational properties of EtOH and other strongly reinforcing stimuli. Given the role of astrocytes in regulating glutamate homeostasis, a crucial component of alcohol use disorder (AUD), astrocytes might be an important target for the development of next-generation alcoholism treatments. This review will outline some of the more prominent features displayed by astrocytes, how these properties are influenced by acute and long-term EtOH exposure, and future directions that may help to disentangle astrocytic from neuronal functions in the etiology of AUD.
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Affiliation(s)
- Louise Adermark
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Sahlgrenska Academy, University of Gothenburg, Box 410, SE-405 30 Gothenburg, Sweden
| | - M. Scott Bowers
- Department of Psychiatry, Virginia Commonwealth University, PO Box 980126, Richmond, VA 23298, USA
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, PO Box 980126, Richmond, VA 23298, USA
- Faulk Center for Molecular Therapeutics, Northwestern University; Aptinyx,, Evanston, Il 60201, USA
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Guizzetti M, Zhang X, Goeke C, Gavin DP. Glia and neurodevelopment: focus on fetal alcohol spectrum disorders. Front Pediatr 2014; 2:123. [PMID: 25426477 PMCID: PMC4227495 DOI: 10.3389/fped.2014.00123] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 10/24/2014] [Indexed: 12/03/2022] Open
Abstract
During the last 20 years, new and exciting roles for glial cells in brain development have been described. Moreover, several recent studies implicated glial cells in the pathogenesis of neurodevelopmental disorders including Down syndrome, Fragile X syndrome, Rett Syndrome, Autism Spectrum Disorders, and Fetal Alcohol Spectrum Disorders (FASD). Abnormalities in glial cell development and proliferation and increased glial cell apoptosis contribute to the adverse effects of ethanol on the developing brain and it is becoming apparent that the effects of fetal alcohol are due, at least in part, to effects on glial cells affecting their ability to modulate neuronal development and function. The three major classes of glial cells, astrocytes, oligodendrocytes, and microglia as well as their precursors are affected by ethanol during brain development. Alterations in glial cell functions by ethanol dramatically affect neuronal development, survival, and function and ultimately impair the development of the proper brain architecture and connectivity. For instance, ethanol inhibits astrocyte-mediated neuritogenesis and oligodendrocyte development, survival and myelination; furthermore, ethanol induces microglia activation and oxidative stress leading to the exacerbation of ethanol-induced neuronal cell death. This review article describes the most significant recent findings pertaining the effects of ethanol on glial cells and their significance in the pathophysiology of FASD and other neurodevelopmental disorders.
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Affiliation(s)
- Marina Guizzetti
- Department of Psychiatry, University of Illinois at Chicago , Chicago, IL , USA ; Jesse Brown VA Medical Center, U.S. Department of Veterans Affairs , Chicago, IL , USA ; Department of Environmental and Occupational Health Sciences, University of Washington , Seattle, WA , USA
| | - Xiaolu Zhang
- Department of Psychiatry, University of Illinois at Chicago , Chicago, IL , USA ; Jesse Brown VA Medical Center, U.S. Department of Veterans Affairs , Chicago, IL , USA
| | - Calla Goeke
- Department of Psychiatry, University of Illinois at Chicago , Chicago, IL , USA ; Jesse Brown VA Medical Center, U.S. Department of Veterans Affairs , Chicago, IL , USA
| | - David P Gavin
- Department of Psychiatry, University of Illinois at Chicago , Chicago, IL , USA ; Jesse Brown VA Medical Center, U.S. Department of Veterans Affairs , Chicago, IL , USA
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Abstract
Calcium is an important intracellular ion involved in numerous cell processes. There are multiple factors that contribute to the release of Ca²⁺. Some factors induce release as part of intracellular signaling cascades, while others result in unwanted changes to both basal and inducible Ca²⁺ levels. The accurate measurement of intracellular Ca²⁺ is, therefore, an important tool in neurotoxicology for assessing compounds/substances that disrupt Ca²⁺ homeostasis. Fluorescent, Ca²⁺-sensitive probes Indo-1 and Fluo-3 allow for the quantification of intracellular Ca²⁺ in individual cells to determine what effects neurotoxins have on both basal and stimulus-dependent Ca²⁺ concentrations.
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VanDemark KL, Guizzetti M, Giordano G, Costa LG. Ethanol inhibits muscarinic receptor-induced axonal growth in rat hippocampal neurons. Alcohol Clin Exp Res 2009; 33:1945-55. [PMID: 19673741 DOI: 10.1111/j.1530-0277.2009.01032.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND In utero alcohol exposure can lead to fetal alcohol spectrum (FAS) disorders characterized by cognitive and behavioral deficits. In vivo and in vitro studies have shown that ethanol alters neuronal development. One mechanism through which ethanol has been shown to exert its effects is the perturbation of activated signaling cascades. The cholinergic agonist carbachol has been shown to induce axonal outgrowth through intracellular calcium mobilization, protein kinase C (PKC) activation, and ERK1/2 phosphorylation. This study investigated the effect of ethanol on the differentiation of rat hippocampal pyramidal neurons induced by carbachol as a possible mechanism involved in the developmental neurotoxicity of ethanol. METHODS Prenatal rat hippocampal pyramidal neurons were treated with ethanol (50 to 75 mM) in the presence or absence of carbachol for 24 hours. Neurite outgrowth was assessed spectrophotometrically; axonal length was measured in neurons fixed and immunolabeled with the neuron-specific betaIII tubulin antibody; cytotoxicity was analyzed using the thiazolyl blue tetrazolium bromide assay. The effect of ethanol on carbachol-stimulated intracellular calcium mobilization was assessed utilizing the fluorescent calcium probe, Fluo-3AM. The PepTag(R) assay for nonradioactive detection of PKC from Promega was used to measure PKC activity, and ERK1/2 activation was determined by densitometric analysis of Western blots probed for phospo-ERK1/2. RESULTS Ethanol treatment (50 to 75 mM) caused an inhibition of carbachol-induced axonal growth, without affecting neuronal viability. Neuron treatment for 15 minutes with ethanol did not inhibit the carbachol-stimulated rise in intracellular calcium, while inhibiting PKC activity at the highest tested concentration and ERK1/2 phosphorylation at both the concentrations used in this study. On the other hand, neuron treatment for 24 hours with ethanol significantly inhibited carbachol-induced increase in intracellular calcium. CONCLUSIONS Ethanol inhibited carbachol-induced neurite outgrowth by inhibiting PKC and ERK1/2 activation. These effects may be, in part, responsible for some of the cognitive deficits associated with in utero alcohol exposure.
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Affiliation(s)
- Kathryn L VanDemark
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
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10
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Guizzetti M, Bordi F, Dieguez-Acuña FJ, Vitalone A, Madia F, Woods JS, Costa LG. Nuclear factor kappaB activation by muscarinic receptors in astroglial cells: effect of ethanol. Neuroscience 2003; 120:941-50. [PMID: 12927200 DOI: 10.1016/s0306-4522(03)00401-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of muscarinic receptors leads to proliferation of astroglial cells and this effect is inhibited by ethanol. Among the intracellular pathways involved in the mitogenic action of muscarinic agonists, activation of the atypical protein kinase C zeta (PKC zeta) appears to be of most importance, and is also affected by low ethanol concentrations. PKC zeta has been reported to activate nuclear factor kappaB (NF-kappaB), a transcription factor that has been shown to play an important role in cell proliferation. The aim of this study was, therefore, to determine whether muscarinic receptors would activate NF-kappaB in astroglial cells, whether such activation would play a role in the mitogenic action of muscarinic agonists, and whether it would represent a possible target for ethanol. Carbachol activated NF-kappaB in human 1321N1 astrocytoma cells, as evidenced by translocation of the p65 subunit of NF-kappaB to the nucleus, phosphorylation and degradation of IkappaBalpha in the cytosol, and increase NF-kappaB binding to DNA. Carbachol also induced translocation of p65 to the nucleus in primary rat astrocytes. Carbachol-induced NF-kappaB activation was mediated by the M3 subtype of muscarinic receptors and appeared to involve Ca(2+) mobilization and activation of PKC epsilon and PKC zeta, but not PI3-kinase and mitogen-activated protein kinase. The NF-kappaB peptide inhibitor SN50, but not the inactive peptide SN50M, strongly inhibited carbachol-induced astrocytoma cells proliferation and p65 translocation to the nucleus. Increased DNA synthesis was also antagonized by the IkappaBalpha kinase inhibitor BAY 11-7082. Ethanol (25-100 mM) inhibited the translocation of p65 and the binding of NF-kappaB to DNA in both 1321N1 astrocytoma cells and primary rat cortical astrocytes. Together, these results suggest that activation of NF-kappaB by muscarinic receptors in astroglial cells is important for carbachol-induced DNA synthesis and that ethanol-mediated inhibition of cell proliferation may be due in part to inhibition of NF-kappaB activation.
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Affiliation(s)
- M Guizzetti
- Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way Northeast 100, Seattle, WA 98105, USA.
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Ma W, Li BS, Maric D, Zhao WQ, Lin HJ, Zhang L, Pant HC, Barker JL. Ethanol blocks both basic fibroblast growth factor- and carbachol-mediated neuroepithelial cell expansion with differential effects on carbachol-activated signaling pathways. Neuroscience 2003; 118:37-47. [PMID: 12676135 DOI: 10.1016/s0306-4522(02)00812-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have expanded neuroepithelial cells dissociated from the embryonic rat telencephalon in serum-free defined medium containing basic fibroblast growth factor (bFGF) in order to generate a model neuroepithelium to study the interaction of ethanol with both growth factor- and transmitter-stimulated proliferation. Ethanol blocked proliferation stimulated by bFGF and by carbachol, an agonist at muscarinic acetylcholine receptors, in a dose-dependent manner. In addition, ethanol attenuated autonomous expansion of neuroepithelial cells occurring following withdrawal of bFGF. The latter effect was associated with an increase in the number of apoptotic cells identified by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling labeling. We studied the effects of ethanol on carbachol-stimulated signaling pathways critical to its proliferative effects. Ethanol significantly reduced carbachol-stimulated Ca(2+) signaling, as well as Erk1/Erk2, Akt and cyclic AMP-response element-binding phosphorylations in a dose-dependent manner. Comparison of the potency of ethanol in attenuating carbachol-stimulated proliferation and signal transduction showed that mitogen-activated protein kinase phosphorylation was less sensitive to ethanol than the other parameters. The results indicate that ethanol's suppression of proliferation induced by carbachol in this model neuroepithelium likely involves multiple signaling pathways. These effects in vitro may help to explain the devastating effects of prenatal ethanol exposure in vivo, which contribute to the fetal alcohol syndrome.
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Affiliation(s)
- W Ma
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, USA.
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Costa LG, Guizzetti M. Inhibition of muscarinic receptor-induced proliferation of astroglial cells by ethanol: mechanisms and implications for the fetal alcohol syndrome. Neurotoxicology 2002; 23:685-91. [PMID: 12520758 DOI: 10.1016/s0161-813x(02)00009-8] [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: 11/30/2022]
Abstract
In utero exposure to ethanol is deleterious to fetal brain development. Children born with the fetal alcohol syndrome (FAS) display a number of abnormalities, the most significant of which are central nervous system (CNS) dysfunctions, such as microencephaly and mental retardation. An interaction of ethanol with glial cells, particularly astrocytes, has been suggested to contribute to the developmental neurotoxicity of this alcohol. At low concentrations (10-100 mM) ethanol inhibits the proliferation of astroglial cells in vitro, particularly when stimulated by acetycholine through muscarinic M3 receptors. Of the several signal transduction pathways activated by these receptors in astrocytes or astrocytoma cells, which are involved in mitogenic signaling, only some (e.g. protein kinase C (PKC) zeta, p70S6 kinase) appear to be targeted by ethanol at the same low concentrations which effectively inhibit proliferation. Inhibition of astroglial proliferation by ethanol may contribute to the microencephaly seen in FAS.
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Affiliation(s)
- Lucio G Costa
- Department of Environmental Health, University of Washington, Seattle, WA, USA.
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Guizzetti M, Costa LG. Effect of ethanol on protein kinase Czeta and p70S6 kinase activation by carbachol: a possible mechanism for ethanol-induced inhibition of glial cell proliferation. J Neurochem 2002; 82:38-46. [PMID: 12091463 DOI: 10.1046/j.1471-4159.2002.00942.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The signal transduction pathways that mediate the mitogenic response of muscarinic acetylcholine receptors in astroglial cells have not been fully elucidated. In this study we investigated the activation of p70S6 kinase (p70S6K) by carbachol in 1321 N1 astroctyoma cells. Carbachol induced a dose- and time-dependent activation of p70S6K, as evidenced by increased phosphorylation at Thr-389, Thr-421 and Ser-424, by increased p70S6K activity, and by a shift in its molecular weight. Activation of p70S6K was mediated by M3 muscarinic acetylcholine receptors (mAChRs) and was inhibited by two phosphatidylinositol-3-kinase (PI3-K) inhibitors, by a pseudosubstrate to protein kinase C (PKC) zeta, and by the p70S6K inhibitor rapamycin. Carbachol-induced DNA synthesis was strongly inhibited by rapamycin, suggesting that p70S6K activation plays an important role in carbachol-induced cell proliferation. Ethanol (25-100 mm) has been shown to inhibit carbachol-induced proliferation of astroglial cells. In the same range of concentrations, ethanol also inhibits carbachol-induced activation of PKCzeta and of p70S6K. On the other hand, inhibition of PI3-kinase was only observed at higher ethanol concentrations. These results indicate that activation of the PKCzeta--> p70S6K pathway by M3 mAChRs may play a role in the increased DNA synthesis and may represent a target for ethanol-induced inhibition of astroglial cell proliferation.
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Affiliation(s)
- Marina Guizzetti
- Department of Environmental Health, University of Washington, 4229 Roosevelt Way NE #100, Seattle, WA 98105, USA.
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Wu M, Shaffer KM, Pancrazio JJ, O'Shaughnessy TJ, Stenger DA, Zhang L, Barker JL, Maric D. Toluene inhibits muscarinic receptor-mediated cytosolic Ca2+ responses in neural precursor cells. Neurotoxicology 2002; 23:61-8. [PMID: 12164548 DOI: 10.1016/s0161-813x(01)00084-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Toluene is widely used as a component in industrial solvents and many toluene-containing products are abused via inhalation. While many studies have demonstrated its inhibitory effects on neuronal activity, the effects of toluene on receptor signaling in proliferating and differentiating neural precursor cells are presently unclear. Here, using digital video microscopy and Ca2+ imaging, we investigated the effects of acute exposure to toluene on the function of muscarinic acetylcholine receptors (mAChRs) expressed in neural precursor cells. The neural precursor cells were isolatedfrom embryonic day 13 (E13) rat cortex and expanded in serum-free medium containing basic fibroblast growth factor (bFGF). We found that the acetylcholine (ACh) analog carbachol (CCh) induced a dose-dependent increase in cytosolic Ca2+, which was blocked by the muscarinic receptor antagonist atropine in a reversible manner. Toluene was added to the perfusion medium and concentrations of toluene in the medium were determined by gas chromatographic analysis. Following imaging, the cells were fixed and processed for 5-bromo-2'-deoxyuridine (BrdU, cell proliferation marker) and beta-tubulin (TuJ1, neuronal marker) immunostaining. In the 5 day culture, most cells continued to divide (BrdU+), while afew cells differentiated into young neurons (TuJ1-). The CCh-induced Ca2+ elevations in proliferating (BrdU+TuJ1-) neural precursor cells were significantly reduced by acute exposure to 0.15 mM toluene and completely blocked by 10 mM toluene. Toluene's inhibition of muscarinic receptor-mediated Ca2+ signaling was rapid, reversible and dose-dependent with an IC50 value 0.5 mM. Since muscarinic receptors mediate cell proliferation and differentiation during neural precursor cell development, these results suggest that depression of muscarinic signaling may play a role in toluene's teratogenic effect on the developing nervous system.
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Affiliation(s)
- M Wu
- Naval Research Laboratory, Center for Bio/Molecular Science and Engineering, Washington, DC 20375, USA.
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15
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Costa LG, Guizzetti M, Lu H, Bordi F, Vitalone A, Tita B, Palmery M, Valeri P, Silvestrini B. Intracellular signal transduction pathways as targets for neurotoxicants. Toxicology 2001; 160:19-26. [PMID: 11246120 DOI: 10.1016/s0300-483x(00)00435-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The multiple cascades of signal transduction pathways that lead from receptors on the cell membrane to the nucleus, thus translating extracellular signals into changes in gene expression, may represent important targets for neurotoxic compounds. Among the biochemical steps and pathways that have been investigated are the metabolism of cyclic nucleotides, the formation of nitric oxide, the metabolism of membrane phospholipids, the activation of a multitude of protein kinases and the induction of transcription factors. This brief review will focus on the interactions of three known neurotoxicants, lead, ethanol and polychlorinated biphenyls, with signal transduction pathways, particularly the family of protein kinase C isozymes, and discusses how such effects may be involved in their neurotoxicity.
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Affiliation(s)
- L G Costa
- Department of Environmental Health, University of Washington, 4225 Roosevelt #100, Seattle, WA 98105, USA.
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Catlin MC, Guizzetti M, Costa LG. Effects of ethanol on calcium homeostasis in the nervous system: implications for astrocytes. Mol Neurobiol 1999; 19:1-24. [PMID: 10321969 DOI: 10.1007/bf02741375] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Ethanol is a major health concern, with neurotoxicity occurring after both in utero exposure and adult alcohol abuse. Despite a large amount of research, the mechanism(s) underlying the neurotoxicity of ethanol remain unknown. One of the cellular aspects that has been investigated in relationship to the neuroteratogenicity and neurotoxicity of ethanol is the maintenance of calcium homeostasis. Studies in neuronal cells and other cells have shown that ethanol can alter intracellular calcium levels and affect voltage and receptor-operated calcium channels, as well as G protein-mediated calcium responses. Despite increasing evidence of the important roles of glial cells in the nervous systems, few studies exist on the potential effects of ethanol on calcium homeostasis in these cells. This brief review discusses a number of reported effects of alcohol on calcium responses that may be relevant to astrocytes' functions.
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Affiliation(s)
- M C Catlin
- Department of Environmental Health, University of Washington, Seattle 98105, USA
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