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Roy TA, Bubier JA, Dickson PE, Wilcox TD, Ndukum J, Clark JW, Sukoff Rizzo SJ, Crabbe JC, Denegre JM, Svenson KL, Braun RE, Kumar V, Murray SA, White JK, Philip VM, Chesler EJ. Discovery and validation of genes driving drug-intake and related behavioral traits in mice. GENES, BRAIN, AND BEHAVIOR 2024; 23:e12875. [PMID: 38164795 PMCID: PMC10780947 DOI: 10.1111/gbb.12875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 11/08/2023] [Accepted: 11/12/2023] [Indexed: 01/03/2024]
Abstract
Substance use disorders are heritable disorders characterized by compulsive drug use, the biological mechanisms for which remain largely unknown. Genetic correlations reveal that predisposing drug-naïve phenotypes, including anxiety, depression, novelty preference and sensation seeking, are predictive of drug-use phenotypes, thereby implicating shared genetic mechanisms. High-throughput behavioral screening in knockout (KO) mice allows efficient discovery of the function of genes. We used this strategy in two rounds of candidate prioritization in which we identified 33 drug-use candidate genes based upon predisposing drug-naïve phenotypes and ultimately validated the perturbation of 22 genes as causal drivers of substance intake. We selected 19/221 KO strains (8.5%) that had a difference from control on at least one drug-naïve predictive behavioral phenotype and determined that 15/19 (~80%) affected the consumption or preference for alcohol, methamphetamine or both. No mutant exhibited a difference in nicotine consumption or preference which was possibly confounded with saccharin. In the second round of prioritization, we employed a multivariate approach to identify outliers and performed validation using methamphetamine two-bottle choice and ethanol drinking-in-the-dark protocols. We identified 15/401 KO strains (3.7%, which included one gene from the first cohort) that differed most from controls for the predisposing phenotypes. 8 of 15 gene deletions (53%) affected intake or preference for alcohol, methamphetamine or both. Using multivariate and bioinformatic analyses, we observed multiple relations between predisposing behaviors and drug intake, revealing many distinct biobehavioral processes underlying these relationships. The set of mouse models identified in this study can be used to characterize these addiction-related processes further.
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Affiliation(s)
- Tyler A. Roy
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Jason A. Bubier
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Price E. Dickson
- Joan C Edwards School of MedicineMarshall UniversityHuntingtonWest VirginiaUSA
| | - Troy D. Wilcox
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Juliet Ndukum
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - James W. Clark
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Stacey J. Sukoff Rizzo
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
- School of MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - John C. Crabbe
- VA Portland Health Care SystemOregon Health & Science UniversityPortlandOregonUSA
| | - James M. Denegre
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Karen L. Svenson
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Robert E. Braun
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Vivek Kumar
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Stephen A. Murray
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | | | - Vivek M. Philip
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
| | - Elissa J. Chesler
- Center for Addiction BiologyThe Jackson LaboratoryBar HarborMaineUSA
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2
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Roy TA, Bubier JA, Dickson PE, Wilcox TD, Ndukum J, Clark JW, Rizzo SJS, Crabbe JC, Denegre JM, Svenson KL, Braun RE, Kumar V, Murray SA, White JK, Philip VM, Chesler EJ. DISCOVERY AND VALIDATION OF GENES DRIVING DRUG-INTAKE AND RELATED BEHAVIORAL TRAITS IN MICE. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.09.548280. [PMID: 37503148 PMCID: PMC10369854 DOI: 10.1101/2023.07.09.548280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Substance use disorders (SUDs) are heritable disorders characterized by compulsive drug use, but the biological mechanisms driving addiction remain largely unknown. Genetic correlations reveal that predisposing drug-naïve phenotypes, including anxiety, depression, novelty preference, and sensation seeking, are predictive of drug-use phenotypes, implicating shared genetic mechanisms. Because of this relationship, high-throughput behavioral screening of predictive phenotypes in knockout (KO) mice allows efficient discovery of genes likely to be involved in drug use. We used this strategy in two rounds of screening in which we identified 33 drug-use candidate genes and ultimately validated the perturbation of 22 of these genes as causal drivers of substance intake. In our initial round of screening, we employed the two-bottle-choice paradigms to assess alcohol, methamphetamine, and nicotine intake. We identified 19 KO strains that were extreme responders on at least one predictive phenotype. Thirteen of the 19 gene deletions (68%) significantly affected alcohol use three methamphetamine use, and two both. In the second round of screening, we employed a multivariate approach to identify outliers and performed validation using methamphetamine two-bottle choice and ethanol drinking-in-the-dark protocols. We identified 15 KO strains that were extreme responders across the predisposing drug-naïve phenotypes. Eight of the 15 gene deletions (53%) significantly affected intake or preference for three alcohol, eight methamphetamine or three both (3). We observed multiple relations between predisposing behaviors and drug intake, revealing many distinct biobehavioral processes underlying these relationships. The set of mouse models identified in this study can be used to characterize these addiction-related processes further.
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Affiliation(s)
| | | | - Price E. Dickson
- Joan C Edwards School of Medicine, Marshall University Huntington, WV
| | | | | | | | - Stacey J. Sukoff Rizzo
- The Jackson Laboratory, Bar Harbor, ME
- University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - John C. Crabbe
- Oregon Health & Science University and VA Portland Health Care System, Portland, OR
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Blednov YA, Da Costa A, Mason S, Mayfield J, Moss SJ, Messing RO. Apremilast-induced increases in acute ethanol intoxication and decreases in ethanol drinking in mice involve PKA phosphorylation of GABA A β3 subunits. Neuropharmacology 2022; 220:109255. [PMID: 36152689 PMCID: PMC9810330 DOI: 10.1016/j.neuropharm.2022.109255] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/23/2022] [Accepted: 09/10/2022] [Indexed: 01/05/2023]
Abstract
We previously showed that apremilast, an FDA-approved PDE4 inhibitor, selectively alters behavioral responses to ethanol and certain GABAergic drugs in a PKA-dependent manner in C57BL6/J mice. Here, we investigated if PKA phosphorylation of β3 GABAA receptor subunits is involved in apremilast regulation of ethanol, propofol, or diazepam responses. Apremilast prolonged rotarod ataxia and loss of the righting reflex by ethanol and propofol in wild-type mice, but not in β3-S408A/S409A knock-in mice. In contrast, apremilast hastened recovery from the ataxic and sedative effects of diazepam in both genotypes. These findings suggest that apremilast modulation of ethanol and propofol behaviors in wild-type mice is mediated by β3 subunit phosphorylation, whereas its actions on diazepam responses involve a different mechanism. The PKA inhibitor H-89 prevented apremilast modulation of ethanol-induced ataxia. Apremilast sensitized wild-type males to ethanol-induced ataxia and decreased acute functional tolerance (AFT) in females but had no effect in β3-S408A/S409A mice of either sex. These results could not be attributed to genotype differences in blood ethanol clearance. There were also no baseline genotype differences in ethanol consumption and preference in two different voluntary drinking procedures. However, the ability of apremilast to reduce ethanol consumption was diminished in β3-S408A/S409A mice. Our results provide strong evidence that PKA-dependent phosphorylation of β3 GABAA receptor subunits is an important mechanism by which apremilast increases acute sensitivity to alcohol, decreases AFT, and decreases ethanol drinking.
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Affiliation(s)
- Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Adriana Da Costa
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Sonia Mason
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Jody Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Robert O Messing
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA; Department of Neuroscience, The University of Texas at Austin, Austin, TX, 78712, USA; Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, 78712, USA.
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Quijano Cardé NA, De Biasi M. Behavioral characterization of withdrawal following chronic voluntary ethanol consumption via intermittent two-bottle choice points to different susceptibility categories. Alcohol Clin Exp Res 2022; 46:614-627. [PMID: 35102570 PMCID: PMC9018532 DOI: 10.1111/acer.14785] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/21/2022] [Accepted: 01/23/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND Alcohol is among the most commonly abused drugs worldwide. Cessation of chronic alcohol consumption can result in the appearance of withdrawal symptoms that commonly promote relapse in individuals with alcohol use disorder (AUD). Thus, preclinical models of voluntary alcohol consumption, in which animals manifest spontaneous signs of withdrawal after alcohol cessation, can be useful for studying AUD and its treatment. The intermittent two-bottle choice paradigm (I2BC) has been used extensively to examine alcohol intake in rodents. However, previous studies have reported conflicting observations regarding its potential to result in the spontaneous manifestation of withdrawal upon alcohol cessation. METHODS We employed a battery of behavioral tests to examine the emergence of affective and physical signs of withdrawal in female and male mice exposed to alcohol in the I2BC for 10 weeks. Specifically, mice of both sexes undergoing 24-h withdrawal from the I2BC were tested for physical signs of withdrawal, anxiety-like behavior in the open field arena (OFA) and elevated plus maze (EPM), and anxiety/compulsive-like behavior in the marble burying test (MBT). The main outcomes from these tests were combined into a behavioral severity score to describe the overall behavioral phenotype. RESULTS Both female and male mice undergoing withdrawal from the I2BC displayed elevated physical signs of withdrawal and anxiety-associated behavior in the EPM and MBT. Analysis of the overall behavioral severity score revealed more severe phenotypes in female and male mice undergoing withdrawal from the I2BC than controls. Additionally, stratification of the mice based on severity scores demonstrated a differential distribution of severities between the exposure groups. CONCLUSIONS We confirmed that a significant fraction of mice chronically exposed to alcohol in the I2BC display spontaneous withdrawal. In addition, we showed that computing a severity score from a combination of behavioral metrics can be useful in preclinical research to model evaluation tools used in patients with AUD.
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Affiliation(s)
- Natalia A Quijano Cardé
- Pharmacology Graduate Group, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Psychiatry, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mariella De Biasi
- Pharmacology Graduate Group, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Psychiatry, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Shi Y, Yu F, Wu Y, Dai L, Feng Y, Chen S, Wang G, Ma H, Li X, Dai C. Identification of a novel peptide that activates alcohol dehydrogenase from crucian carp swim bladder and how it protects against acute alcohol-induced liver injury in mice. J Pharm Biomed Anal 2022; 207:114426. [PMID: 34689062 DOI: 10.1016/j.jpba.2021.114426] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/06/2021] [Accepted: 10/06/2021] [Indexed: 12/21/2022]
Abstract
Alcoholism is a severe threat to public health, and there are no adequate treatments for alcoholic liver disease. The aim of this study was to identify bioactive peptides derived from natural proteins that prevent acute alcohol-induced liver injury. We identified a peptide with the sequence Gly-Leu-hydroxyproline-Gly-Glu-Arg (GLpGER) from the hydrolysate of crucian carp swim bladder using size-exclusion chromatography and reversed-phase chromatography. The in vitro EC50 value of GLpGER to activate alcohol dehydrogenase (ADH) was 137.9 ± 9 µM. Molecular docking experiments indicated that the mechanism by which GLpGER activates ADH may be related to the formation of stable complexes with ADH active pockets through hydrogen bonding, and electrostatic and hydrophobic interactions. Oral administration of GLpGER one hour before acute alcohol ingestion significantly increased alcohol metabolism, manifesting as reduced incidence of the loss of righting reflex, increased alcohol tolerance time, shortened sobering time, and decreased blood alcohol concentration level. GLpGER restored liver ADH activity, maintained the typical morphology of hepatocytes, and reduced serum levels of alanine aminotransferase and aspartate aminotransferase. These findings suggest that GLpGER might reduce acute alcohol-induced liver injury and may have the potential to be developed as an anti-inebriation ingredient.
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Affiliation(s)
- Yiting Shi
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Fengjie Yu
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yi Wu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Lin Dai
- Experimental Teaching Center of Life Science, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yutong Feng
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Shilei Chen
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Guoxiang Wang
- Experimental Teaching Center of Life Science, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Hongyu Ma
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Xitong Li
- International Education College, Nanjing Forestry University, Nanjing 210037, China
| | - Chen Dai
- Experimental Teaching Center of Life Science, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
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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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7
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Loftis JM, Navis T, Taylor J, Hudson R, Person U, Lattal KM, Vandenbark AA, Shirley R, Huckans M. Partial MHC/neuroantigen peptide constructs attenuate methamphetamine-seeking and brain chemokine (C-C motif) ligand 2 levels in rats. Eur J Pharmacol 2020; 880:173175. [PMID: 32416183 DOI: 10.1016/j.ejphar.2020.173175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/09/2020] [Accepted: 05/06/2020] [Indexed: 11/28/2022]
Abstract
There are no medications that target the neurotoxic effects or reduce the use of methamphetamine. Recombinant T-cell receptor ligand (RTL) 1000 [a partial major histocompatibility complex (pMHC) class II construct with a tethered myelin peptide], addresses the neuroimmune effects of methamphetamine addiction by competitively inhibiting the disease-promoting activity of macrophage migration inhibitory factor to CD74, a key pathway involved in several chronic inflammatory conditions, including substance use disorders. We previously reported that RTL constructs improve learning and memory impairments and central nervous system (CNS) inflammation induced by methamphetamine in mouse models. The present study in Lewis rats evaluated the effects of RTL1000 on maintenance of self-administration and cue-induced reinstatement using operant behavioral methods. Post-mortem brain and serum samples were evaluated for the levels of inflammatory factors. Rats treated with RTL1000 displayed significantly fewer presses on the active lever as compared to rats treated with vehicle during the initial extinction session, indicating more rapid extinction in the presence of RTL1000. Immunoblotting of rat brain sections revealed reduced levels of the pro-inflammatory chemokine (C-C motif) ligand 2 (CCL2) in the frontal cortex of rats treated with RTL1000, as compared to vehicle. Post hoc analysis identified a positive association between the levels of CCL2 detected in the frontal cortex and the number of lever presses during the first extinction session. Taken together, results suggest that RTL1000 may block downstream inflammatory effects of methamphetamine exposure and facilitate reduced drug seeking-potentially offering a new strategy for the treatment of methamphetamine-induced CNS injury and neuropsychiatric impairments.
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Affiliation(s)
- Jennifer M Loftis
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA; Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA; Methamphetamine Research Center, Portland, OR, USA.
| | - Tommy Navis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Jonathan Taylor
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA; Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA
| | - Rebekah Hudson
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA
| | - Ulziibat Person
- Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA
| | - K Matthew Lattal
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Arthur A Vandenbark
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA; Department of Neurology, Oregon Health & Science University, Portland, OR, USA; Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR, USA
| | - Renee Shirley
- Virogenomics BioDevelopment, Inc., Portland, OR, USA
| | - Marilyn Huckans
- Research & Development Service, Veterans Affairs Portland Health Care System, Portland, OR, USA; Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA; Methamphetamine Research Center, Portland, OR, USA; Mental Health and Clinical Neurosciences Division, Veterans Affairs Portland Health Care System, Portland, OR, USA
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8
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Most D, Salem NA, Tiwari GR, Blednov YA, Mayfield RD, Harris RA. Silencing synaptic MicroRNA-411 reduces voluntary alcohol consumption in mice. Addict Biol 2019; 24:604-616. [PMID: 29665166 DOI: 10.1111/adb.12625] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/09/2018] [Accepted: 03/19/2018] [Indexed: 12/12/2022]
Abstract
Chronic alcohol consumption alters the levels of microRNAs and mRNAs in the brain, but the specific microRNAs and processes that target mRNAs to affect cellular function and behavior are not known. We examined the in vivo manipulation of previously identified alcohol-responsive microRNAs as potential targets to reduce alcohol consumption. Silencing of miR-411 by infusing antagomiR-411 into the prefrontal cortex of female C57BL/6J mice reduced alcohol consumption and preference, without altering total fluid consumption, saccharin consumption, or anxiety-related behaviors. AntagomiR-411 reduced alcohol consumption when given to mice exposed to a chronic alcohol drinking paradigm but did not affect the acquisition of consumption in mice without a history of alcohol exposure, suggesting that antagomiR-411 has a neuroadaptive, alcohol-dependent effect. AntagomiR-411 decreased the levels of miR-411, as well as the association of immunoprecipitated miR-411 with Argonaute2; and, it increased levels of Faah and Ppard mRNAs. Moreover, antagomiR-411 increased the neuronal expression of glutamate receptor AMPA-2 protein, a known alcohol target and a predicted target of miR-411. These results suggest that alcohol and miR-411 function in a homeostatic manner to regulate synaptic mRNA and protein, thus reversing alcohol-related neuroadaptations and reducing chronic alcohol consumption.
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Affiliation(s)
- Dana Most
- Waggoner Center for Alcohol and Addiction ResearchThe University of Texas at Austin Austin TX USA
- Institute for NeuroscienceUniversity of Texas at Austin Austin TX USA
| | - Nihal A. Salem
- Texas A&M Institute for Neuroscience and Department of Neuroscience and Experimental Therapeutics, College of MedicineTexas A&M University College Station TX USA
| | - Gayatri R. Tiwari
- Waggoner Center for Alcohol and Addiction ResearchThe University of Texas at Austin Austin TX USA
| | - Yuri A. Blednov
- Waggoner Center for Alcohol and Addiction ResearchThe University of Texas at Austin Austin TX USA
| | - R. Dayne Mayfield
- Waggoner Center for Alcohol and Addiction ResearchThe University of Texas at Austin Austin TX USA
| | - R. Adron Harris
- Waggoner Center for Alcohol and Addiction ResearchThe University of Texas at Austin Austin TX USA
- Institute for NeuroscienceUniversity of Texas at Austin Austin TX USA
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9
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Blednov YA, Da Costa AJ, Harris RA, Messing RO. Apremilast Alters Behavioral Responses to Ethanol in Mice: II. Increased Sedation, Intoxication, and Reduced Acute Functional Tolerance. Alcohol Clin Exp Res 2018; 42:939-951. [PMID: 29469954 DOI: 10.1111/acer.13615] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 02/15/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND In our companion paper, we reported that the phosphodiesterase type 4 inhibitor apremilast reduced ethanol (EtOH) intake and preference in different drinking models in male and female C57BL/6J mice. In this study, we measured the effects of apremilast on other behaviors that are correlated with EtOH consumption. METHODS The effects of apremilast (20 mg/kg) on the following behaviors were studied in male and female C57BL/6J mice: locomotor response to a novel situation; EtOH- and lithium chloride (LiCl)-induced conditioned taste aversion (CTA) to saccharin; conditioned place preference (CPP) and conditioned place avoidance (CPA) to EtOH; severity of handling-induced convulsions after EtOH administration; EtOH-induced anxiolytic-like behavior in the elevated plus maze; duration of EtOH-induced loss of righting reflex (LORR); recovery from EtOH-induced motor impairment on the rotarod; and acute functional tolerance (AFT) to EtOH's ataxic effects. RESULTS Apremilast did not change the acquisition of EtOH-induced CPP, severity of acute withdrawal from EtOH, or EtOH's anxiolytic-like effect. Apremilast did not alter the extinction of EtOH- or LiCl-induced CTA, but may interfere with acquisition of CTA to EtOH. Apremilast increased the acquisition of CPA to EtOH, reduced locomotor responses to a novel situation, and prolonged the duration of LORR and the recovery from acute motor incoordination induced by EtOH. The longer recovery from the ataxic effect may be attributed to reduced development of AFT to EtOH. CONCLUSIONS Our results suggest that apremilast increases the duration of EtOH intoxication by reducing AFT. Apremilast also reduces some aspects of general reward and increases EtOH's aversive properties, which might also contribute to its ability to reduce EtOH drinking.
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Affiliation(s)
- Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin, Austin, Texas, 78712
| | - Adriana J Da Costa
- Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin, Austin, Texas, 78712
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin, Austin, Texas, 78712
| | - Robert O Messing
- Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin, Austin, Texas, 78712.,Department of Neurology , The University of Texas at Austin, Austin, Texas, 78712
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10
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Blednov YA, Black M, Chernis J, Da Costa A, Mayfield J, Harris RA. Ethanol Consumption in Mice Lacking CD14, TLR2, TLR4, or MyD88. Alcohol Clin Exp Res 2017; 41:516-530. [PMID: 28146272 PMCID: PMC5332291 DOI: 10.1111/acer.13316] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 12/14/2016] [Indexed: 12/13/2022]
Abstract
BACKGROUND Molecular and behavioral studies support a role for innate immune proinflammatory pathways in mediating the effects of alcohol. Increased levels of Toll-like receptors (TLRs) have been observed in animal models of alcohol consumption and in human alcoholics, and many of these TLRs signal via the MyD88-dependent pathway. We hypothesized that this pathway is involved in alcohol drinking and examined some of its key signaling components. METHODS Different ethanol (EtOH)-drinking paradigms were studied in male and female control C57BL/6J mice versus mice lacking CD14, TLR2, TLR4 (C57BL/10ScN), or MyD88. We studied continuous and intermittent access 2-bottle choice (2BC) and 1-bottle and 2BC drinking-in-the-dark (DID) tests as well as preference for saccharin, quinine, and NaCl. RESULTS In the 2BC continuous access test, EtOH intake decreased in male TLR2 knockout (KO) mice, and we previously reported reduced 2BC drinking in male and female CD14 KO mice. In the intermittent access 2BC test, EtOH intake decreased in CD14 KO male and female mice, whereas drinking increased in MyD88 KO male mice. In the 2BC-DID test, EtOH drinking decreased in male and female mice lacking TLR2, whereas drinking increased in MyD88 KO male mice. In the 1-bottle DID test, EtOH intake decreased in female TLR2 KO mice. TLR2 KO and CD14 KO mice did not differ in saccharin preference but showed reduced preference for NaCl. MyD88 KO mice showed a slight reduction in preference for saccharin. CONCLUSIONS Deletion of key components of the MyD88-dependent pathway produced differential effects on EtOH intake by decreasing (TLR2 KO and CD14 KO) or increasing (MyD88 KO) drinking, while deletion of TLR4 had no effect. Some of the drinking effects depended on the sex of the mice and/or the EtOH-drinking model.
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Affiliation(s)
- Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Mendy Black
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Julia Chernis
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Adriana Da Costa
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Jody Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
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11
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Abstract
Multiple lines of evidence strongly indicate that genetic factors contribute to the risk for alcohol use disorders (AUD). There is substantial heterogeneity in AUD, which complicates studies seeking to identify specific genetic factors. To identify these genetic effects, several different alcohol-related phenotypes have been analyzed, including diagnosis and quantitative measures related to AUDs. Study designs have used candidate gene analyses, genetic linkage studies, genomewide association studies (GWAS), and analyses of rare variants. Two genes that encode enzymes of alcohol metabolism have the strongest effect on AUD: aldehyde dehydrogenase 2 and alcohol dehydrogenase 1B each has strongly protective variants that reduce risk, with odds ratios approximately 0.2-0.4. A number of other genes important in AUD have been identified and replicated, including GABRA2 and alcohol dehydrogenases 1B and 4. GWAS have identified additional candidates. Rare variants are likely also to play a role; studies of these are just beginning. A multifaceted approach to gene identification, targeting both rare and common variations and assembling much larger datasets for meta-analyses, is critical for identifying the key genes and pathways important in AUD.
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Affiliation(s)
- Howard J Edenberg
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Tatiana Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
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12
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Sekhon ML, Lamina O, Hogan KE, Kliethermes CL. Common genes regulate food and ethanol intake in Drosophila. Alcohol 2016; 53:27-34. [PMID: 27286934 DOI: 10.1016/j.alcohol.2016.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/22/2016] [Accepted: 04/01/2016] [Indexed: 12/19/2022]
Abstract
The abuse liability of alcohol (ethanol) is believed to result in part from its actions on neurobiological substrates that underlie the motivation toward food and other natural reinforcers, and a growing body of evidence indicates that these substrates are broadly conserved among animal phyla. Understanding the extent to which the substrates regulating ethanol and food intake overlap is an important step toward developing therapeutics that selectively reduce ethanol intake. In the current experiments, we measured food and ethanol intake in Recombinant Inbred (RI) lines of Drosophila melanogaster using several assays, and then calculated genetic correlations to estimate the degree to which common genes might underlie behavior in these assays. We found that food intake and ethanol intake as measured in the capillary assay are genetically correlated traits in D. melanogaster, as well as in a panel of 11 Drosophila species that we tested subsequently. RI line differences in food intake in a dyed food assay were genetically unrelated to ethanol intake in the capillary assay or to ethanol preference measured using an olfactory trap apparatus. Using publicly available gene expression data, we found that expression profiles across the RI lines of a number of genes (including the D2-like dopamine receptor, DOPA decarboxylase, and fruitless) correlated with the RI line differences in food and ethanol intake we measured, while the expression profiles of other genes, including NPF, and the NPF and 5-HT2 receptors, correlated only with ethanol intake or preference. Our results suggest that food and ethanol intake are regulated by some common genes in Drosophila, but that other genes regulate ethanol intake independently of food intake. These results have implications toward the development of therapeutics that preferentially reduce ethanol intake.
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Affiliation(s)
- Morgan L Sekhon
- Drake University, Department of Psychology and Neuroscience, Des Moines, IA, USA
| | - Omoteniola Lamina
- Drake University, Department of Psychology and Neuroscience, Des Moines, IA, USA
| | - Kerry E Hogan
- Drake University, Department of Psychology and Neuroscience, Des Moines, IA, USA
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13
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Blednov YA, Black M, Benavidez JM, Stamatakis EE, Harris RA. PPAR Agonists: II. Fenofibrate and Tesaglitazar Alter Behaviors Related to Voluntary Alcohol Consumption. Alcohol Clin Exp Res 2016; 40:563-71. [PMID: 26857541 DOI: 10.1111/acer.12972] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 11/21/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND In the accompanying article, we showed that activation of peroxisome proliferator-activated receptor alpha (PPARα) signaling by fenofibrate and tesaglitazar decreases ethanol (EtOH) consumption in mice. In this study, we determined the role of these PPAR agonists in EtOH-related behaviors and other actions that may be important in regulating EtOH consumption. METHODS The effects of fenofibrate (150 mg/kg) and tesaglitazar (1.5 mg/kg) were examined on the following responses in male and female C57BL/6J (B6) and B6 × 129S4 mice: preference for saccharin, EtOH-induced conditioned place preference (CPP), conditioned taste aversion (CTA), loss of righting reflex, and withdrawal, acoustic startle reflex, response to novelty, and EtOH clearance. Because the B6 inbred strain usually displays weak EtOH-induced CPP and weak EtOH-induced acute withdrawal, B6 × 129S4 mice were also studied. RESULTS Fenofibrate and tesaglitazar decreased the novelty response and increased acute EtOH withdrawal severity, and fenofibrate increased EtOH-induced CTA. Two important factors for EtOH consumption (saccharin preference and EtOH-induced CPP) were not altered by fenofibrate or tesaglitazar. EtOH clearance was increased by both fenofibrate and tesaglitazar. Response to novelty, acute withdrawal, and EtOH clearance show sex differences and could contribute to the reduced EtOH consumption following fenofibrate administration. CONCLUSIONS These studies indicate the complexity of EtOH-dependent and EtOH-independent behaviors that are altered by PPAR agonists and provide evidence for novel behavioral actions of these drugs that may contribute to PPAR-mediated effects on alcohol drinking.
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Affiliation(s)
- Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Mendy Black
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Jillian M Benavidez
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Eleni E Stamatakis
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
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Synaptic microRNAs Coordinately Regulate Synaptic mRNAs: Perturbation by Chronic Alcohol Consumption. Neuropsychopharmacology 2016; 41:538-48. [PMID: 26105134 PMCID: PMC5130129 DOI: 10.1038/npp.2015.179] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 05/27/2015] [Accepted: 06/06/2015] [Indexed: 11/08/2022]
Abstract
Local translation of mRNAs in the synapse has a major role in synaptic structure and function. Chronic alcohol use causes persistent changes in synaptic mRNA expression, possibly mediated by microRNAs localized in the synapse. We profiled the transcriptome of synaptoneurosomes (SN) obtained from the amygdala of mice that consumed 20% ethanol (alcohol) in a 30-day continuous two-bottle choice test to identify the microRNAs that target alcohol-induced mRNAs. SN are membrane vesicles containing pre- and post-synaptic compartments of neurons and astroglia and are a unique model for studying the synaptic transcriptome. We previously showed that chronic alcohol regulates mRNA expression in a coordinated manner. Here, we examine microRNAs and mRNAs from the same samples to define alcohol-responsive synaptic microRNAs and their predicted interactions with targeted mRNAs. The aim of the study was to identify the microRNA-mRNA synaptic interactions that are altered by alcohol. This was accomplished by comparing the effect of alcohol in SN and total homogenate preparations from the same samples. We used a combination of unbiased bioinformatic methods (differential expression, correlation, co-expression, microRNA-mRNA target prediction, co-targeting, and cell type-specific analyses) to identify key alcohol-sensitive microRNAs. Prediction analysis showed that a subset of alcohol-responsive microRNAs was predicted to target many alcohol-responsive mRNAs, providing a bidirectional analysis for identifying microRNA-mRNA interactions. We found microRNAs and mRNAs with overlapping patterns of expression that correlated with alcohol consumption. Cell type-specific analysis revealed that a significant number of alcohol-responsive mRNAs and microRNAs were unique to glutamate neurons and were predicted to target each other. Chronic alcohol consumption appears to perturb the coordinated microRNA regulation of mRNAs in SN, a mechanism that may explain the aberrations in synaptic plasticity affecting the alcoholic brain.
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Huckans M, Fuller BE, Chalker ALN, Adams M, Loftis JM. Plasma Inflammatory Factors Are Associated with Anxiety, Depression, and Cognitive Problems in Adults with and without Methamphetamine Dependence: An Exploratory Protein Array Study. Front Psychiatry 2015; 6:178. [PMID: 26732994 PMCID: PMC4683192 DOI: 10.3389/fpsyt.2015.00178] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 12/04/2015] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVES It is hypothesized that immune factors influence addictive behaviors and contribute to relapse. The primary study objectives were to (1) compare neuropsychiatric symptoms across adults with active methamphetamine (MA) dependence, in early remission from MA dependence, and with no history of substance dependence, (2) determine whether active or recent MA dependence affects the expression of immune factors, and (3) evaluate the association between immune factor levels and neuropsychiatric symptoms. METHODS A cross-sectional study was conducted using between group comparisons and regression analyses to investigate associations among variables. Eighty-four adults were recruited into control (CTL) (n = 31), MA-active (n = 17), or MA-remission (n = 36) groups. Participants completed self-report measures of anxiety, depression, and memory complaints and objective tests of attention and executive function. Blood samples were collected, and a panel of immune factors was measured using multiplex technology. RESULTS Relative to CTLs, MA-dependent adults evidenced greater anxiety and depression during active use (p < 0.001) and remission (p < 0.007), and more attention, memory, and executive problems during remission (p < 0.01) but not active dependence. Regression analyses identified 10 immune factors (putatively associated with cytokine-cytokine receptor interactions) associated with anxiety, depression, and memory problems. CONCLUSION While psychiatric symptoms are present during active MA dependence and remission, at least some cognitive difficulties emerge only during remission. Altered expression of a network of immune factors contributes to neuropsychiatric symptom severity.
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Affiliation(s)
- Marilyn Huckans
- Research and Development Service, VA Portland Health Care System, Portland, OR, USA
- Mental Health and Clinical Neurosciences Division, VA Portland Health Care System, Portland, OR, USA
- Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA
- Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, USA
| | - Bret E. Fuller
- Research and Development Service, VA Portland Health Care System, Portland, OR, USA
- Mental Health and Clinical Neurosciences Division, VA Portland Health Care System, Portland, OR, USA
| | - Alison L. N. Chalker
- Research and Development Service, VA Portland Health Care System, Portland, OR, USA
| | - Madeleine Adams
- Research and Development Service, VA Portland Health Care System, Portland, OR, USA
| | - Jennifer M. Loftis
- Research and Development Service, VA Portland Health Care System, Portland, OR, USA
- Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA
- Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, USA
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16
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Mayfield J, Blednov YA, Harris RA. Behavioral and Genetic Evidence for GIRK Channels in the CNS: Role in Physiology, Pathophysiology, and Drug Addiction. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 123:279-313. [PMID: 26422988 DOI: 10.1016/bs.irn.2015.05.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
G protein-coupled inwardly rectifying potassium (GIRK) channels are widely expressed throughout the brain and mediate the inhibitory effects of many neurotransmitters. As a result, these channels are important for normal CNS function and have also been implicated in Down syndrome, Parkinson's disease, psychiatric disorders, epilepsy, and drug addiction. Knockout mouse models have provided extensive insight into the significance of GIRK channels under these conditions. This review examines the behavioral and genetic evidence from animal models and genetic association studies in humans linking GIRK channels with CNS disorders. We further explore the possibility that subunit-selective modulators and other advanced research tools will be instrumental in establishing the role of individual GIRK subunits in drug addiction and other relevant CNS diseases and in potentially advancing treatment options for these disorders.
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Affiliation(s)
- Jody Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA.
| | - Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas, USA
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17
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Loftis JM, Janowsky A. Neuroimmune basis of methamphetamine toxicity. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 118:165-97. [PMID: 25175865 DOI: 10.1016/b978-0-12-801284-0.00007-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although it is not known which antigen-specific immune responses (or if antigen-specific immune responses) are relevant or required for methamphetamine's neurotoxic effects, it is apparent that methamphetamine exposure is associated with significant effects on adaptive and innate immunity. Alterations in lymphocyte activity and number, changes in cytokine signaling, impairments in phagocytic functions, and glial activation and gliosis have all been reported. These drug-induced changes in immune response, particularly within the CNS, are now thought to play a critical role in the addiction process for methamphetamine dependence as well as for other substance use disorders. In Section 2, methamphetamine's effects on glial cell (e.g., microglia and astrocytes) activity and inflammatory signaling cascades are summarized, including how alterations in immune cell function can induce the neurotoxic and addictive effects of methamphetamine. Section 2 also describes neurotransmitter involvement in the modulation of methamphetamine's inflammatory effects. Section 3 discusses the very recent use of pharmacological and genetic animal models which have helped elucidate the behavioral effects of methamphetamine's neurotoxic effects and the role of the immune system. Section 4 is focused on the effects of methamphetamine on blood-brain barrier integrity and associated immune consequences. Clinical considerations such as the combined effects of methamphetamine and HIV and/or HCV on brain structure and function are included in Section 4. Finally, in Section 5, immune-based treatment strategies are reviewed, with a focus on vaccine development, neuroimmune therapies, and other anti-inflammatory approaches.
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Affiliation(s)
- Jennifer M Loftis
- Research & Development Service, Portland VA Medical Center, Portland, Oregon, USA; Department of Psychiatry, Oregon Health & Science University, School of Medicine, Portland, Oregon, USA; Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, Oregon, USA.
| | - Aaron Janowsky
- Research & Development Service, Portland VA Medical Center, Portland, Oregon, USA; Department of Psychiatry, Oregon Health & Science University, School of Medicine, Portland, Oregon, USA; Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, Oregon, USA; Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, USA
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18
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Oren Y, Nachshon A, Frishberg A, Wilentzik R, Gat-Viks I. Linking traits based on their shared molecular mechanisms. eLife 2015; 4. [PMID: 25781485 PMCID: PMC4362207 DOI: 10.7554/elife.04346] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 02/20/2015] [Indexed: 12/29/2022] Open
Abstract
There is growing recognition that co-morbidity and co-occurrence of disease traits are often determined by shared genetic and molecular mechanisms. In most cases, however, the specific mechanisms that lead to such trait-trait relationships are yet unknown. Here we present an analysis of a broad spectrum of behavioral and physiological traits together with gene-expression measurements across genetically diverse mouse strains. We develop an unbiased methodology that constructs potentially overlapping groups of traits and resolves their underlying combination of genetic loci and molecular mechanisms. For example, our method predicts that genetic variation in the Klf7 gene may influence gene transcripts in bone marrow-derived myeloid cells, which in turn affect 17 behavioral traits following morphine injection; this predicted effect of Klf7 is consistent with an in vitro perturbation of Klf7 in bone marrow cells. Our analysis demonstrates the utility of studying hidden causative mechanisms that lead to relationships between complex traits.
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Affiliation(s)
- Yael Oren
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Aharon Nachshon
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Amit Frishberg
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Roni Wilentzik
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Irit Gat-Viks
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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19
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Individual differences in risk-related behaviors and voluntary alcohol intake in outbred Wistar rats. Behav Pharmacol 2014; 25:206-15. [PMID: 24776488 DOI: 10.1097/fbp.0000000000000036] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Some personality traits and comorbid psychiatric diseases are linked to a propensity for excessive alcohol drinking. The objective of this study was to investigate the association between individual differences in risk-related behaviors, voluntary alcohol intake and preference. Outbred male Wistar rats were tested in a novel open field, followed by assessment of behavioral profiles using the multivariate concentric square field (MCSF) test. Animals were classified into high risk taking and low risk taking on the basis of open-field behavior and into high risk-assessing (HRA) and low risk-assessing (LRA) on the basis of the MCSF profile. Finally, voluntary alcohol intake was investigated using intermittent access to 20% ethanol and water for 5 weeks. Only minor differences in voluntary alcohol intake were found between high risk taking and low risk taking. Differences between HRA and LRA rats were more evident, with higher intake and increased intake over time in HRA relative to LRA rats. Thus, individual differences in risk-assessment behavior showed greater differences in voluntary alcohol intake than risk taking. The findings may relate to human constructs of decision-making and risk taking associated with a predisposition to rewarding and addictive behaviors. Further studies are needed to clarify the relationship between risk-related behaviors, including risk-assessment behavior, and liability for excessive alcohol intake.
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20
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Grisel JE, Beasley JB, Bertram EC, Decker BE, Duan CA, Etuma M, Hand A, Locklear MN, Whitmire MP. Initial subjective reward: single-exposure conditioned place preference to alcohol in mice. Front Neurosci 2014; 8:345. [PMID: 25408633 PMCID: PMC4219544 DOI: 10.3389/fnins.2014.00345] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 10/09/2014] [Indexed: 11/21/2022] Open
Abstract
Most adults consume alcohol with relative impunity, but about 10–20% of users persist (or progress) in their consumption, despite mounting and serious repercussions. Identifying at-risk individuals before neuroadaptative changes associated with chronic use become well ingrained is thus a key step in mitigating and preventing the end stage disease and its devastating impacts. Explaining liability has been impeded, in part, by the absence of animal models for assessing initial sensitivity to the drug's reinforcing properties, an important endophenotype in the trajectory toward excessive drinking. Here we assess the initial rewarding effects of the drug in a novel application of the conditioned place preference paradigm. In contrast to previous studies that have all employed repeated drug administration, we demonstrated a robust preference for a context paired with a single exposure to 1.5 g/kg EtOH in male and female subjects of three strains. This model validates an assay of initial sensitivity to the subjective rewarding effects of alcohol, a widely used drug with multifarious impacts on both brain and society, and provides a new tool for theory-driven endophenotypic pharmacogenetic approaches to understanding and treating addiction.
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Affiliation(s)
| | | | | | | | - Chunyu A Duan
- Neuroscience, Furman University Greenville, SC, USA ; Princeton Neuroscience Institute, Princeton University Princeton, NJ, USA
| | - Mahder Etuma
- Neuroscience, Bucknell University Lewisburg, PA, USA
| | - Annie Hand
- Neuroscience, Furman University Greenville, SC, USA
| | - Mallory N Locklear
- Neuroscience, Furman University Greenville, SC, USA ; Neurology and Behavior, Stony Brook University, State University of New York Stony Brook, NY, USA
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Trudell JR, Messing RO, Mayfield J, Harris RA. Alcohol dependence: molecular and behavioral evidence. Trends Pharmacol Sci 2014; 35:317-23. [PMID: 24865944 PMCID: PMC4089033 DOI: 10.1016/j.tips.2014.04.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/18/2014] [Accepted: 04/30/2014] [Indexed: 10/25/2022]
Abstract
Alcohol dependence is a complex condition with clear genetic factors. Some of the leading candidate genes code for subunits of the inhibitory GABAA and glycine receptors. These and related ion channels are also targets for the acute actions of alcohol, and there is considerable progress in understanding interactions of alcohol with these proteins at the molecular and even atomic levels. X-ray structures of open and closed states of ion channels combined with structural modeling and site-directed mutagenesis have elucidated direct actions of alcohol. Alcohol also alters channel function by translational and post-translational mechanisms, including phosphorylation and protein trafficking. Construction of mutant mice with either deletion of key proteins or introduction of alcohol-resistant channels has further linked specific proteins with discrete behavioral effects of alcohol. A combination of approaches, including genome wide association studies in humans, continues to advance the molecular basis of alcohol action on receptor structure and function.
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Affiliation(s)
- James R Trudell
- Department of Anesthesia, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Robert O Messing
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jody Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712, USA
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712, USA.
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22
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Wyatt LR, Finn DA, Khoja S, Yardley MM, Asatryan L, Alkana RL, Davies DL. Contribution of P2X4 receptors to ethanol intake in male C57BL/6 mice. Neurochem Res 2014; 39:1127-39. [PMID: 24671605 DOI: 10.1007/s11064-014-1271-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/15/2014] [Accepted: 02/26/2014] [Indexed: 11/26/2022]
Abstract
P2X receptors (P2XRs) are a family of cation-permeable ligand-gated ion channels activated by synaptically released extracellular adenosine 5'-triphosphate. The P2X4 subtype is abundantly expressed in the central nervous system and is sensitive to low intoxicating ethanol concentrations. Genetic meta-analyses identified the p2rx4 gene as a candidate gene for innate alcohol intake and/or preference. The current study used mice lacking the p2rx4 gene (knockout, KO) and wildtype (WT) C57BL/6 controls to test the hypothesis that P2X4Rs contribute to ethanol intake. The early acquisition and early maintenance phases of ethanol intake were measured with three different drinking procedures. Further, we tested the effects of ivermectin (IVM), a drug previously shown to reduce ethanol's effects on P2X4Rs and to reduce ethanol intake and preference, for its ability to differentially alter stable ethanol intake in KO and WT mice. Depending on the procedure and the concentration of the ethanol solution, ethanol intake was transiently increased in P2X4R KO versus WT mice during the acquisition of 24-h and limited access ethanol intake. IVM significantly reduced ethanol intake in P2X4R KO and WT mice, but the degree of reduction was 50 % less in the P2X4R KO mice. Western blot analysis identified significant changes in γ-aminobutyric acidA receptor α1 subunit expression in brain regions associated with the regulation of ethanol behaviors in P2X4R KO mice. These findings add to evidence that P2X4Rs contribute to ethanol intake and indicate that there is a complex interaction between P2X4Rs, ethanol, and other neurotransmitter receptor systems.
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Affiliation(s)
- Letisha R Wyatt
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA, 90033, USA
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23
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Fritz BM, Cordero KA, Barkley-Levenson AM, Metten P, Crabbe JC, Boehm SL. Genetic relationship between predisposition for binge alcohol consumption and blunted sensitivity to adverse effects of alcohol in mice. Alcohol Clin Exp Res 2014; 38:1284-92. [PMID: 24612020 DOI: 10.1111/acer.12385] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 01/07/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Initial sensitivity to ethanol (EtOH) and the capacity to develop acute functional tolerance (AFT) to its adverse effects may influence the amount of alcohol consumed and may also predict future alcohol use patterns. The current study assessed sensitivity and AFT to the ataxic and hypnotic effects of EtOH in the first replicate of mice (HDID-1) selectively bred for high blood EtOH concentrations (BECs) following limited access to EtOH in the Drinking in the Dark (DID) paradigm. METHODS Naïve male and female HDID-1 and HS/Npt mice from the progenitor stock were evaluated in 3 separate experiments. In Experiments 1 and 2, EtOH-induced ataxia was assessed using the static dowel task. In Experiment 3, EtOH-induced hypnosis was assessed by using modified restraint tubes to measure the loss of righting reflex (LORR). RESULTS HDID-1 mice exhibited reduced initial sensitivity to both EtOH-induced ataxia (p < 0.001) and hypnosis (p < 0.05) relative to HS/Npt mice. AFT was calculated by subtracting the BEC at loss of function from the BEC at recovery (Experiments 1 and 3) or by subtracting BEC at an initial recovery from the BEC at a second recovery following an additional alcohol dose (Experiment 2). The dowel test yielded no line differences in AFT, but HS/Npt mice developed slightly greater AFT to EtOH-induced LORR than HDID-1 (p < 0.05). CONCLUSIONS These results suggest that HDID-1 mice exhibit aspects of blunted ataxic and hypnotic sensitivity to EtOH which may influence their high EtOH intake via DID, but do not display widely different development of AFT. These findings differ from previous findings with the high alcohol-preferring (HAP) selected mouse lines, suggesting that genetic predisposition for binge, versus other forms of excessive alcohol consumption, is associated with unique responses to EtOH-induced motor incoordination.
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Affiliation(s)
- Brandon M Fritz
- Indiana Alcohol Research Center , Department of Psychology, Indiana University, Purdue University Indianapolis, Indianapolis, Indiana
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Howard RJ, Trudell JR, Harris RA. Seeking structural specificity: direct modulation of pentameric ligand-gated ion channels by alcohols and general anesthetics. Pharmacol Rev 2014; 66:396-412. [PMID: 24515646 PMCID: PMC3973611 DOI: 10.1124/pr.113.007468] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alcohols and other anesthetic agents dramatically alter neurologic function in a wide range of organisms, yet their molecular sites of action remain poorly characterized. Pentameric ligand-gated ion channels, long implicated in important direct effects of alcohol and anesthetic binding, have recently been illuminated in renewed detail thanks to the determination of atomic-resolution structures of several family members from lower organisms. These structures provide valuable models for understanding and developing anesthetic agents and for allosteric modulation in general. This review surveys progress in this field from function to structure and back again, outlining early evidence for relevant modulation of pentameric ligand-gated ion channels and the development of early structural models for ion channel function and modulation. We highlight insights and challenges provided by recent crystal structures and resulting simulations, as well as opportunities for translation of these newly detailed models back to behavior and therapy.
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Affiliation(s)
- Rebecca J Howard
- Department of Chemistry, Skidmore College, Saratoga Springs, NY 12866.
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Lum EN, Campbell RR, Rostock C, Szumlinski KK. mGluR1 within the nucleus accumbens regulates alcohol intake in mice under limited-access conditions. Neuropharmacology 2014; 79:679-87. [PMID: 24467847 DOI: 10.1016/j.neuropharm.2014.01.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 12/31/2013] [Accepted: 01/11/2014] [Indexed: 02/05/2023]
Abstract
Idiopathic or alcohol-induced increases in the expression and function of the Group1 metabotropic glutamate receptor subtype 1 (mGluR1) within the extended amygdala are theorized to contribute to an individual's propensity to consume excessive amounts of alcohol. In the past, the detailed study of the functional relevance of mGluR1 for alcoholism-related behaviors in animal models was hampered by the poor solubility and non-specific side effects of available inhibitors; however, the advent of the highly potent and soluble mGluR1 negative allosteric modulator JNJ-16259685 [(3,4-Dihydro-2H-pyrano[2,3-b]quinolin-7-yl)-(cis-4-methoxycyclohexyl)-methanone] has instigated a re-examination of the role for this mGluR subtype in mediating the behavioral effects of alcohol. In this regard, systemic pretreatment with JNJ-16259685 was proven effective at reducing alcohol reinforcement and motivation for the drug. mGluR1 is a Gαq/o-coupled receptor, the stimulation of which activates phospholipase C (PLC). Thus, the present study investigated potential neuroanatomical substrates and intracellular molecules involved in the ability of JNJ-16259685 to reduce alcohol intake. JNJ-16259685 (0-30 pg/side) was infused into the shell subregion of the nucleus accumbens (NAC) of C57BL/6J and Homer2 knock-out (KO) mice, either alone or in combination with the PLC inhibitor U-73122 (5.8 fg/side). Alcohol intake was then assessed under Drinking-in-the-Dark (DID) procedures. Intra-NAC JNJ-16259685 infusion dose-dependently reduced alcohol consumption by C57BL/6J mice; this effect was not additive with that produced by U-73122, nor was it present in Homer2 KO animals. These data provide novel evidence in support of a critical role for mGluR1-PLC signaling, scaffolded by Homer2, within the NAC shell, in maintaining alcohol consumption under limited access procedures. Such findings have relevance for both the pharmacotherapeutics and pharmacogenetics of risky alcohol drinking and alcoholism.
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Affiliation(s)
- Emily N Lum
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA 93106-9660, USA
| | - Rianne R Campbell
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA 93106-9660, USA
| | - Charlotte Rostock
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA 93106-9660, USA
| | - Karen K Szumlinski
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA 93106-9660, USA.
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Cozzoli DK, Courson J, Wroten MG, Greentree DI, Lum EN, Campbell RR, Thompson AB, Maliniak D, Worley PF, Jonquieres G, Klugmann M, Finn DA, Szumlinski KK. Binge alcohol drinking by mice requires intact group 1 metabotropic glutamate receptor signaling within the central nucleus of the amygdala. Neuropsychopharmacology 2014; 39:435-44. [PMID: 23966068 PMCID: PMC3870786 DOI: 10.1038/npp.2013.214] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 08/13/2013] [Accepted: 08/19/2013] [Indexed: 01/16/2023]
Abstract
Despite the fact that binge alcohol drinking (intake resulting in blood alcohol concentrations (BACs) 80 mg% within a 2-h period) is the most prevalent form of alcohol-use disorders (AUD), a large knowledge gap exists regarding how this form of AUD influences neural circuits mediating alcohol reinforcement. The present study employed integrative approaches to examine the functional relevance of binge drinking-induced changes in glutamate receptors, their associated scaffolding proteins and certain signaling molecules within the central nucleus of the amygdala (CeA). A 30-day history of binge alcohol drinking (for example, 4-5 g kg(-1) per 2 h(-1)) elevated CeA levels of mGluR1, GluN2B, Homer2a/b and phospholipase C (PLC) β3, without significantly altering protein expression within the adjacent basolateral amygdala. An intra-CeA infusion of mGluR1, mGluR5 and PLC inhibitors all dose-dependently reduced binge intake, without influencing sucrose drinking. The effects of co-infusing mGluR1 and PLC inhibitors were additive, whereas those of coinhibiting mGluR5 and PLC were not, indicating that the efficacy of mGluR1 blockade to lower binge intake involves a pathway independent of PLC activation. The efficacy of mGluR1, mGluR5 and PLC inhibitors to reduce binge intake depended upon intact Homer2 expression as revealed through neuropharmacological studies of Homer2 null mutant mice. Collectively, these data indicate binge alcohol-induced increases in Group1 mGluR signaling within the CeA as a neuroadaptation maintaining excessive alcohol intake, which may contribute to the propensity to binge drink.
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Affiliation(s)
- Debra K Cozzoli
- Department of Behavioral Neuroscience, VA Medical Research, Oregon Health & Science University, Portland, OR, USA
| | - Justin Courson
- Department of Psychological and Brain Sciences, Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
| | - Melissa G Wroten
- Department of Psychological and Brain Sciences, Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
| | - Daniel I Greentree
- Department of Psychological and Brain Sciences, Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
| | - Emily N Lum
- Department of Psychological and Brain Sciences, Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
| | - Rianne R Campbell
- Department of Psychological and Brain Sciences, Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
| | - Andrew B Thompson
- Department of Psychological and Brain Sciences, Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
| | - Dan Maliniak
- Department of Psychological and Brain Sciences, Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
| | - Paul F Worley
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Georg Jonquieres
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Matthias Klugmann
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Deborah A Finn
- Department of Behavioral Neuroscience, VA Medical Research, Oregon Health & Science University, Portland, OR, USA
| | - Karen K Szumlinski
- Department of Psychological and Brain Sciences, Neuroscience Research Institute, University of California, Santa Barbara, CA, USA
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Charbogne P, Kieffer BL, Befort K. 15 years of genetic approaches in vivo for addiction research: Opioid receptor and peptide gene knockout in mouse models of drug abuse. Neuropharmacology 2013; 76 Pt B:204-17. [PMID: 24035914 DOI: 10.1016/j.neuropharm.2013.08.028] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 08/19/2013] [Accepted: 08/23/2013] [Indexed: 12/21/2022]
Abstract
The endogenous opioid system is expressed throughout the brain reinforcement circuitry, and plays a major role in reward processing, mood control and the development of addiction. This neuromodulator system is composed of three receptors, mu, delta and kappa, interacting with a family of opioid peptides derived from POMC (β-endorphin), preproenkephalin (pEnk) and preprodynorphin (pDyn) precursors. Knockout mice targeting each gene of the opioid system have been created almost two decades ago. Extending classical pharmacology, these mutant mice represent unique tools to tease apart the specific role of each opioid receptor and peptide in vivo, and a powerful approach to understand how the opioid system modulates behavioral effects of drugs of abuse. The present review summarizes these studies, with a focus on major drugs of abuse including morphine/heroin, cannabinoids, psychostimulants, nicotine or alcohol. Genetic data, altogether, set the mu receptor as the primary target for morphine and heroin. In addition, this receptor is essential to mediate rewarding properties of non-opioid drugs of abuse, with a demonstrated implication of β-endorphin for cocaine and nicotine. Delta receptor activity reduces levels of anxiety and depressive-like behaviors, and facilitates morphine-context association. pEnk is involved in these processes and delta/pEnk signaling likely regulates alcohol intake. The kappa receptor mainly interacts with pDyn peptides to limit drug reward, and mediate dysphoric effects of cannabinoids and nicotine. Kappa/dynorphin activity also increases sensitivity to cocaine reward under stressful conditions. The opioid system remains a prime candidate to develop successful therapies in addicted individuals, and understanding opioid-mediated processes at systems level, through emerging genetic and imaging technologies, represents the next challenging goal and a promising avenue in addiction research. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Affiliation(s)
- Pauline Charbogne
- IGBMC Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR 7104 - Inserm U964, Illkirch F-67404, France; CNRS, UMR7104, Illkirch F-67404, France; UdS Université de Strasbourg, CNRS UMR 7104 - Inserm U964, Illkirch F-67404, France; Inserm U964, Illkirch F-67404, France
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Chesler EJ, Logan RW. Opportunities for bioinformatics in the classification of behavior and psychiatric disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013. [PMID: 23195316 DOI: 10.1016/b978-0-12-398323-7.00008-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A bioinformatics approach to behavioral neuroscience provides both unique opportunities and challenges for research on behavior. A major challenge has been to describe, define, and discriminate among abstract behavioral processes, in large part by distinguishing among the biological mechanisms of unique but not entirely discrete, entities of behavior. Understanding the complexity of neurobiology and behavior requires integration of data across diverse biological systems, types of data, and levels of scale. With the perspective and application of bioinformatics, we can uncover the relationships among these systems and take steps forward in realizing the common and distinct bases of psychiatric disease.
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Loftis JM, Huckans M. Substance use disorders: psychoneuroimmunological mechanisms and new targets for therapy. Pharmacol Ther 2013; 139:289-300. [PMID: 23631821 DOI: 10.1016/j.pharmthera.2013.04.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 04/15/2013] [Indexed: 12/28/2022]
Abstract
An estimated 76.4 million people worldwide meet criteria for alcohol use disorders, and 15.3 million meet criteria for drug use disorders. Given the high rates of addiction and the associated health, economic, and social costs, it is essential to develop a thorough understanding of the impact of substance abuse on mental and physical health outcomes and to identify new treatment approaches for substance use disorders (SUDs). Psychoneuroimmunology is a rapidly expanding, multidisciplinary area of research that may be of particular importance to addiction medicine, as its focus is on the dynamic and complex interactions among behavioral factors, the central nervous system, and the endocrine and immune systems (Ader, 2001). This review, therefore, focuses on: 1) the psychoneuroimmunologic effects of SUDs by substance type and use pattern, and 2) the current and future treatment strategies, including barriers that can impede successful recovery outcomes. Evidence-based psychosocial and pharmacotherapeutic treatments are reviewed. Psychological factors and central nervous system correlates that impact treatment adherence and response are discussed. Several novel therapeutic approaches that are currently under investigation are introduced; translational data from animal and human studies is presented, highlighting immunotherapy as a promising new direction for addiction medicine.
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Affiliation(s)
- Jennifer M Loftis
- Research and Development Service, Portland VA Medical Center, Portland, OR, USA.
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Crews FT, Qin L, Sheedy D, Vetreno RP, Zou J. High mobility group box 1/Toll-like receptor danger signaling increases brain neuroimmune activation in alcohol dependence. Biol Psychiatry 2013; 73:602-12. [PMID: 23206318 PMCID: PMC3602398 DOI: 10.1016/j.biopsych.2012.09.030] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/30/2012] [Accepted: 09/19/2012] [Indexed: 12/30/2022]
Abstract
BACKGROUND Innate immune gene expression is regulated in part through high mobility group box 1 (HMGB1), an endogenous proinflammatory cytokine, that activates multiple members of the interleukin-1/Toll-like receptor (TLR) family associated with danger signaling. We investigated expression of HMGB1, TLR2, TLR3, and TLR4 in chronic ethanol-treated mouse brain, postmortem human alcoholic brain, and rat brain slice culture to test the hypothesis that neuroimmune activation in alcoholic brain involves ethanol activation of HMGB1/TLR danger signaling. METHODS Protein levels were assessed using Western blot, enzyme-linked immunosorbent assay, and immunohistochemical immunoreactivity (+IR), and messenger RNA (mRNA) levels were measured by real time polymerase chain reaction in ethanol-treated mice (5 g/kg/day, intragastric, 10 days + 24 hours), rat brain slice culture, and postmortem human alcoholic brain. RESULTS Ethanol treatment of mice increased brain mRNA and +IR protein expression of HMGB1, TLR2, TLR3, and TLR4. Postmortem human alcoholic brain also showed increased HMGB1, TLR2, TLR3, and TLR4 +IR cells that correlated with lifetime alcohol consumption, as well as each other. Ethanol treatment of brain slice culture released HMGB1 into the media and induced the proinflammatory cytokine, interleukin-1 beta (IL-1β). Neutralizing antibodies to HMGB1 and small inhibitory mRNA to HMGB1 or TLR4 blunted ethanol induction of IL-1β. CONCLUSIONS Ethanol-induced HMGB1/TLR signaling contributes to induction of the proinflammatory cytokine, IL-1β. Increased expression of HMGB1, TLR2, TLR3, and TLR4 in alcoholic brain and in mice treated with ethanol suggests that chronic alcohol-induced brain neuroimmune activation occurs through HMGB1/TLR signaling.
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Affiliation(s)
- Fulton T Crews
- Bowles Center for Alcohol Studies, Department of Pharmacology and Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7178, USA.
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Iancu OD, Oberbeck D, Darakjian P, Metten P, McWeeney S, Crabbe JC, Hitzemann R. Selection for drinking in the dark alters brain gene coexpression networks. Alcohol Clin Exp Res 2013; 37:1295-303. [PMID: 23550792 DOI: 10.1111/acer.12100] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 12/18/2012] [Indexed: 12/29/2022]
Abstract
BACKGROUND Heterogeneous stock (HS/NPT) mice have been used to create lines selectively bred in replicate for elevated drinking in the dark (DID). Both selected lines routinely reach a blood ethanol (EtOH) concentration (BEC) of 1.00 mg/ml or greater at the end of the 4-hour period of access in Day 2. The mechanisms through which genetic differences influence DID are currently unclear. Therefore, the current study examines the transcriptome, the first stage at which genetic variability affects neurobiology. Rather than focusing solely on differential expression (DE), we also examine changes in the ways that gene transcripts collectively interact with each other, as revealed by changes in coexpression patterns. METHODS Naïve mice (N = 48/group) were genotyped using the Mouse Universal Genotyping Array, which provided 3,683 informative markers. Quantitative trait locus (QTL) analysis used a marker-by-marker strategy with the threshold for a significant logarithm of odds (LOD) set at 10.6. Gene expression in the ventral striatum was measured using the Illumina Mouse 8.2 array. Differential gene expression and the weighted gene coexpression network analysis (WGCNA) were implemented largely as described elsewhere. RESULTS Significant QTLs for elevated BECs after DID were detected on chromosomes 4, 14, and 16; the latter 2 were associated with gene-poor regions. None of the QTLs overlapped with known QTLs for EtOH preference drinking. Ninety-four transcripts were detected as being differentially expressed in both selected lines versus HS controls; there was no overlap with known preference genes. The WGCNA revealed 2 modules as showing significant effects of both selections on intramodular connectivity. A number of genes known to be associated with EtOH phenotypes (e.g., Gabrg1, Glra2, Grik1, Npy2r, and Nts) showed significant changes in connectivity. CONCLUSIONS We found marked and consistent effects of selection on coexpression patterns; DE changes were more modest and less concordant. The QTLs and differentially expressed genes detected here are distinct from the preference phenotype. This is consistent with behavioral data and suggests that the DID and preference phenotypes are markedly different genetically.
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Affiliation(s)
- Ovidiu D Iancu
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA.
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Neuroimmune signaling: a key component of alcohol abuse. Curr Opin Neurobiol 2013; 23:513-20. [PMID: 23434064 DOI: 10.1016/j.conb.2013.01.024] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/16/2013] [Accepted: 01/24/2013] [Indexed: 12/13/2022]
Abstract
Molecular and behavioral studies corroborate a pivotal role for the innate immune system in mediating the acute and chronic effects of alcohol and support a neuroimmune hypothesis of alcohol addiction. Changes in expression of neuroimmune genes and microglial transcripts occur in postmortem brain from alcoholics and animals exposed to alcohol, and null mutant animals lacking certain innate immune genes show decreased alcohol-mediated responses. Many of the differentially expressed genes are part of the toll like receptor (TLR) signaling pathway and culminate in an increased expression of pro-inflammatory immune genes. Compounds known to inhibit inflammation, microglial activation, and neuroimmune gene expression have shown promising results in reducing alcohol-mediated behaviors in animal models, indicating that neuroimmune signaling pathways offer unexplored targets in the treatment of alcohol abuse.
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Blednov YA, Benavidez JM, Black M, Chandra D, Homanics GE, Rudolph U, Harris RA. Linking GABA(A) receptor subunits to alcohol-induced conditioned taste aversion and recovery from acute alcohol intoxication. Neuropharmacology 2012; 67:46-56. [PMID: 23147414 DOI: 10.1016/j.neuropharm.2012.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Revised: 10/12/2012] [Accepted: 10/28/2012] [Indexed: 10/27/2022]
Abstract
GABA type A receptors (GABA(A)-R) are important for ethanol actions and it is of interest to link individual subunits with specific ethanol behaviors. We studied null mutant mice for six different GABA(A)-R subunits (α1, α2, α3, α4, α5 and δ). Only mice lacking the α2 subunit showed reduction of conditioned taste aversion (CTA) to ethanol. These results are in agreement with data from knock-in mice with mutation of the ethanol-sensitive site in the α2-subunit (Blednov et al., 2011). All together, they indicate that aversive property of ethanol is dependent on ethanol action on α2-containing GABA(A)-R. Deletion of the α2-subunit led to faster recovery whereas absence of the α3-subunit slowed recovery from ethanol-induced incoordination (rotarod). Deletion of the other four subunits did not affect this behavior. Similar changes in this behavior for the α2 and α3 null mutants were found for flurazepam motor incoordination. However, no differences in recovery were found in motor-incoordinating effects of an α1-selective modulator (zolpidem) or an α4-selective agonist (gaboxadol). Therefore, recovery of rotarod incoordination is under control of two GABA(A)-R subunits: α2 and α3. For motor activity, α3 null mice demonstrated higher activation by ethanol (1 g/kg) whereas both α2 (-/-) and α3 (-/Y) knockout mice were less sensitive to ethanol-induced reduction of motor activity (1.5 g/kg). These studies demonstrate that the effects of ethanol at GABAergic synapses containing α2 subunit are important for specific behavioral effects of ethanol which may be relevant to the genetic linkage of the α2 subunit with human alcoholism.
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Affiliation(s)
- Y A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, 1 University Station, A4800, Austin, TX 78712, USA.
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