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Lathen DR, Merrill CB, Rothenfluh A. Flying Together: Drosophila as a Tool to Understand the Genetics of Human Alcoholism. Int J Mol Sci 2020; 21:E6649. [PMID: 32932795 PMCID: PMC7555299 DOI: 10.3390/ijms21186649] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/14/2022] Open
Abstract
Alcohol use disorder (AUD) exacts an immense toll on individuals, families, and society. Genetic factors determine up to 60% of an individual's risk of developing problematic alcohol habits. Effective AUD prevention and treatment requires knowledge of the genes that predispose people to alcoholism, play a role in alcohol responses, and/or contribute to the development of addiction. As a highly tractable and translatable genetic and behavioral model organism, Drosophila melanogaster has proven valuable to uncover important genes and mechanistic pathways that have obvious orthologs in humans and that help explain the complexities of addiction. Vinegar flies exhibit remarkably strong face and mechanistic validity as a model for AUDs, permitting many advancements in the quest to understand human genetic involvement in this disease. These advancements occur via approaches that essentially fall into one of two categories: (1) discovering candidate genes via human genome-wide association studies (GWAS), transcriptomics on post-mortem tissue from AUD patients, or relevant physiological connections, then using reverse genetics in flies to validate candidate genes' roles and investigate their molecular function in the context of alcohol. (2) Utilizing flies to discover candidate genes through unbiased screens, GWAS, quantitative trait locus analyses, transcriptomics, or single-gene studies, then validating their translational role in human genetic surveys. In this review, we highlight the utility of Drosophila as a model for alcoholism by surveying recent advances in our understanding of human AUDs that resulted from these various approaches. We summarize the genes that are conserved in alcohol-related function between humans and flies. We also provide insight into some advantages and limitations of these approaches. Overall, this review demonstrates how Drosophila have and can be used to answer important genetic questions about alcohol addiction.
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Affiliation(s)
- Daniel R. Lathen
- Department of Psychiatry and Neuroscience Ph.D. Program, University of Utah, Salt Lake City, UT 84108, USA;
| | - Collin B. Merrill
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA;
| | - Adrian Rothenfluh
- Department of Psychiatry and Neuroscience Ph.D. Program, University of Utah, Salt Lake City, UT 84108, USA;
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA;
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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2
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Amaral VCS, Morais-Silva G, Laverde CF, Marin MT. Susceptibility to extinction and reinstatement of ethanol-induced conditioned place preference is related to differences in astrocyte cystine-glutamate antiporter content. Neurosci Res 2020; 170:245-254. [PMID: 32653617 DOI: 10.1016/j.neures.2020.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/22/2020] [Accepted: 07/07/2020] [Indexed: 12/25/2022]
Abstract
Individual susceptibility to alcohol effects plays an important role in the development of alcohol addiction and studies have shown that glutamate release is altered after chronic ethanol consumption. The cystine-glutamate antiporter (xCT) is a protein that regulates glutamate release. However, little is known about the relationship between xCT levels and this individual susceptibility. Thus, this study aimed to evaluate the relationship between the extinction and stress-induced reinstatement of ethanol conditioned place preference (CPP) and xCT levels in the medial prefrontal cortex (mPFC), nucleus accumbens (NAcc) and amygdala (Amy). Male Swiss mice were submitted to a CPP procedure followed by an extinction protocol and then identified as those which extinguished the CPP and those that did not. In another cohort, mice that extinguished the CPP were submitted to a protocol of stress-induced reinstatement. Immediately after the tests, brains were removed for xCT quantification. The xCT levels were significantly lower in the mPFC and NAcc of mice that did not extinguish CPP. Moreover, mice that were susceptible to stress-induced reinstatement of CPP had lower levels of xCT in the NAcc. Our results suggest that individual susceptibility to the extinction and reinstatement of ethanol CPP is related to alterations in xCT levels.
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Affiliation(s)
- Vanessa Cristiane Santana Amaral
- Laboratory of Pharmacology and Toxicology of Natural and Synthetic Products, State University of Goias, Exact and Technological Sciences Campus, Anapolis, GO, Brazil; São Paulo State University (UNESP), School of Pharmaceutical Sciences, Laboratory of Pharmacology, Araraquara, SP, Brazil; Joint Graduate Program in Physiological Sciences (PIPGCF), UFSCar/UNESP, São Carlos/Araraquara, SP, Brazil
| | - Gessynger Morais-Silva
- São Paulo State University (UNESP), School of Pharmaceutical Sciences, Laboratory of Pharmacology, Araraquara, SP, Brazil; Joint Graduate Program in Physiological Sciences (PIPGCF), UFSCar/UNESP, São Carlos/Araraquara, SP, Brazil
| | - Celina F Laverde
- São Paulo State University (UNESP), School of Pharmaceutical Sciences, Laboratory of Pharmacology, Araraquara, SP, Brazil; Joint Graduate Program in Physiological Sciences (PIPGCF), UFSCar/UNESP, São Carlos/Araraquara, SP, Brazil
| | - Marcelo T Marin
- São Paulo State University (UNESP), School of Pharmaceutical Sciences, Laboratory of Pharmacology, Araraquara, SP, Brazil; Joint Graduate Program in Physiological Sciences (PIPGCF), UFSCar/UNESP, São Carlos/Araraquara, SP, Brazil.
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3
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Jury NJ, Radke AK, Pati D, Kocharian A, Mishina M, Kash TL, Holmes A. NMDA receptor GluN2A subunit deletion protects against dependence-like ethanol drinking. Behav Brain Res 2018; 353:124-128. [PMID: 29953905 PMCID: PMC6092743 DOI: 10.1016/j.bbr.2018.06.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 06/21/2018] [Accepted: 06/25/2018] [Indexed: 12/13/2022]
Abstract
The N-methyl-D-aspartate receptor (NMDAR) is mechanistically involved in the behavioral and neurophysiological effects of alcohol, but the specific role of the GluN2A subunit remains unclear. Here, we exposed mice with constitutive GluN2A gene knockout (KO) to chronic intermittent ethanol vapor (CIE) and tested for EtOH consumption/preference using a two-bottle choice paradigm, as well as NMDAR-mediated transmission at basolateral amygdala synapses via ex vivo slice electrophysiology. Results showed that GluN2A KO mice attained comparable blood EtOH levels in response to CIE exposure, but did not exhibit the significant increase in EtOH drinking that was observed in CIE-exposed wildtypes. GluN2A KO mice also showed no alterations in BLA NMDAR-mediated synaptic transmission after CIE, relative to air-exposed, whereas C57BL/6 J mice showed an attenuated synaptic response to GluN2B antagonism. Taken together, these data add to mounting evidence supporting GluN2A-containing NMDARs as a mechanism underlying relative risk for developing EtOH dependence after repeated EtOH exposure.
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Affiliation(s)
- Nicholas J Jury
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
| | - Anna K Radke
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Dipanwita Pati
- Bowles Center for Alcohol Studies, Departments of Pharmacology and Psychiatry, UNC Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Adrina Kocharian
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Masayoshi Mishina
- Brain Science Laboratory, The Research Organization of Science and Technology, Ritsumeikan University, Shiga, Japan
| | - Thomas L Kash
- Bowles Center for Alcohol Studies, Departments of Pharmacology and Psychiatry, UNC Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
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Bell RL, Hauser SR, McClintick J, Rahman S, Edenberg HJ, Szumlinski KK, McBride WJ. Ethanol-Associated Changes in Glutamate Reward Neurocircuitry: A Minireview of Clinical and Preclinical Genetic Findings. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 137:41-85. [PMID: 26809998 DOI: 10.1016/bs.pmbts.2015.10.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Herein, we have reviewed the role of glutamate, the major excitatory neurotransmitter in the brain, in a number of neurochemical, -physiological, and -behavioral processes mediating the development of alcohol dependence. The findings discussed include results from both preclinical as well as neuroimaging and postmortem clinical studies. Expression levels for a number of glutamate-associated genes and/or proteins are modulated by alcohol abuse and dependence. These changes in expression include metabotropic receptors and ionotropic receptor subunits as well as different glutamate transporters. Moreover, these changes in gene expression parallel the pharmacologic manipulation of these same receptors and transporters. Some of these gene expression changes may have predated alcohol abuse and dependence because a number of glutamate-associated polymorphisms are related to a genetic predisposition to develop alcohol dependence. Other glutamate-associated polymorphisms are linked to age at the onset of alcohol-dependence and initial level of response/sensitivity to alcohol. Finally, findings of innate and/or ethanol-induced glutamate-associated gene expression differences/changes observed in a genetic animal model of alcoholism, the P rat, are summarized. Overall, the existing literature indicates that changes in glutamate receptors, transporters, enzymes, and scaffolding proteins are crucial for the development of alcohol dependence and there is a substantial genetic component to these effects. This indicates that continued research into the genetic underpinnings of these glutamate-associated effects will provide important novel molecular targets for treating alcohol abuse and dependence.
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Affiliation(s)
- Richard L Bell
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA.
| | - Sheketha R Hauser
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Jeanette McClintick
- Departments of Biochemistry and Molecular Biology and Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana , USA
| | - Shafiqur Rahman
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, South Dakota, USA
| | - Howard J Edenberg
- Departments of Biochemistry and Molecular Biology and Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana , USA
| | - Karen K Szumlinski
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, California, USA
| | - William J McBride
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Bach P, Kirsch M, Hoffmann S, Jorde A, Mann K, Frank J, Charlet K, Beck A, Heinz A, Walter H, Rietschel M, Kiefer F, Vollstädt-Klein S. The effects of single nucleotide polymorphisms in glutamatergic neurotransmission genes on neural response to alcohol cues and craving. Addict Biol 2015; 20:1022-32. [PMID: 26289945 DOI: 10.1111/adb.12291] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/24/2015] [Accepted: 07/14/2015] [Indexed: 11/29/2022]
Abstract
The aim of the current study was to determine genotype effects of four single nucleotide polymorphisms (SNPs) in the genes of the N-Methyl-d-aspartate receptor (GRIN1, GRIN2A, GRIN2C) and kainate receptor (GRIK1), which have been previously associated with alcoholism, on behavior, neural cue-reactivity and drinking outcome. Eighty-six abstinent alcohol dependent patients were recruited from an in-patient setting. Neuropsychological tests, genotyping and functional magnetic resonance imaging (fMRI) were used to study genotype effects. GRIN2C risk allele carriers displayed increased alcohol cue-induced activation in the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (dlPFC). Neural activation in the ACC positively correlated with craving for alcohol (r = 0.201, P = 0.032), whereas activation in the dlPFC showed a negative association (r = -0.215, P = 0.023). In addition, dlPFC activation predicted time to first relapse (HR = 2.701, 95%CI 1.244-5.864, P = 0.012). GRIK1 risk allele carriers showed increased cue-induced activation in the medial prefrontal (PFC) and orbitofrontal cortex (OFC) and in the lateral PFC and OFC. Activation in both clusters positively correlated with alcohol craving (rmedOFC, medPFC = 0.403, P = 0.001, rlatOFC, latPFC = 0.282, P = 0.008), and activation in the cluster that encompassed the medial OFC predicted time to first relapse (HR = 1.911, 95%CI 1.030-3.545, P = 0.040). Findings indicate that SNPs in the GRIN2C and GRIK1 genes are associated with altered cue-induced brain activation that is related to craving for alcohol and relapse risk.
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Affiliation(s)
- Patrick Bach
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
| | - Martina Kirsch
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
| | - Sabine Hoffmann
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
| | - Anne Jorde
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
| | - Karl Mann
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
| | - Josef Frank
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
| | - Katrin Charlet
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte; Charité-Universitätsmedizin; Germany
| | - Anne Beck
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte; Charité-Universitätsmedizin; Germany
| | - Andreas Heinz
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte; Charité-Universitätsmedizin; Germany
| | - Henrik Walter
- Division of Mind and Brain Research, Department of Psychiatry and Psychotherapy; Charité-Universitätsmedizin; Germany
| | - Marcella Rietschel
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
| | - Falk Kiefer
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
| | - Sabine Vollstädt-Klein
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health; Medical Faculty Mannheim, University of Heidelberg; Germany
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6
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Carey CE, Agrawal A, Zhang B, Conley ED, Degenhardt L, Heath AC, Li D, Lynskey MT, Martin NG, Montgomery GW, Wang T, Bierut LJ, Hariri AR, Nelson EC, Bogdan R. Monoacylglycerol lipase (MGLL) polymorphism rs604300 interacts with childhood adversity to predict cannabis dependence symptoms and amygdala habituation: Evidence from an endocannabinoid system-level analysis. JOURNAL OF ABNORMAL PSYCHOLOGY 2015; 124:860-77. [PMID: 26595473 PMCID: PMC4700831 DOI: 10.1037/abn0000079] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Despite evidence for heritable variation in cannabis involvement and the discovery of cannabinoid receptors and their endogenous ligands, no consistent patterns have emerged from candidate endocannabinoid (eCB) genetic association studies of cannabis involvement. Given interactions between eCB and stress systems and associations between childhood stress and cannabis involvement, it may be important to consider childhood adversity in the context of eCB-related genetic variation. We employed a system-level gene-based analysis of data from the Comorbidity and Trauma Study (N = 1,558) to examine whether genetic variation in six eCB genes (anabolism: DAGLA, DAGLB, NAPEPLD; catabolism: MGLL, FAAH; binding: CNR1; SNPs N = 65) and childhood sexual abuse (CSA) predict cannabis dependence symptoms. Significant interactions with CSA emerged for MGLL at the gene level (p = .009), and for rs604300 within MGLL (ΔR2 = .007, p < .001), the latter of which survived SNP-level Bonferroni correction and was significant in an additional sample with similar directional effects (N = 859; ΔR2 = .005, p = .026). Furthermore, in a third sample (N = 312), there was evidence that rs604300 genotype interacts with early life adversity to predict threat-related basolateral amygdala habituation, a neural phenotype linked to the eCB system and addiction (ΔR2 = .013, p = .047). Rs604300 may be related to epigenetic modulation of MGLL expression. These results are consistent with rodent models implicating 2-arachidonoylglycerol (2-AG), an endogenous cannabinoid metabolized by the enzyme encoded by MGLL, in the etiology of stress adaptation related to cannabis dependence, but require further replication.
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Affiliation(s)
- Caitlin E Carey
- Department of Psychology, Washington University in St. Louis
| | - Arpana Agrawal
- Department of Psychiatry, Washington University in St. Louis
| | - Bo Zhang
- Department of Genetics, Washington University in St. Louis
| | | | - Louisa Degenhardt
- National Drug and Alcohol Research Centre, University of New South Wales
| | - Andrew C Heath
- Department of Psychiatry, Washington University in St. Louis
| | - Daofeng Li
- Department of Genetics, Washington University in St. Louis
| | | | | | | | - Ting Wang
- Department of Genetics, Washington University in St. Louis
| | - Laura J Bierut
- Department of Psychiatry, Washington University in St. Louis
| | - Ahmad R Hariri
- Department of Psychology and Neuroscience, Duke University
| | - Elliot C Nelson
- Department of Psychiatry, Washington University in St. Louis
| | - Ryan Bogdan
- Department of Psychology, Washington University in St. Louis
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7
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Bühler KM, Giné E, Echeverry-Alzate V, Calleja-Conde J, de Fonseca FR, López-Moreno JA. Common single nucleotide variants underlying drug addiction: more than a decade of research. Addict Biol 2015; 20:845-71. [PMID: 25603899 DOI: 10.1111/adb.12204] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Drug-related phenotypes are common complex and highly heritable traits. In the last few years, candidate gene (CGAS) and genome-wide association studies (GWAS) have identified a huge number of single nucleotide polymorphisms (SNPs) associated with drug use, abuse or dependence, mainly related to alcohol or nicotine. Nevertheless, few of these associations have been replicated in independent studies. The aim of this study was to provide a review of the SNPs that have been most significantly associated with alcohol-, nicotine-, cannabis- and cocaine-related phenotypes in humans between the years of 2000 and 2012. To this end, we selected CGAS, GWAS, family-based association and case-only studies published in peer-reviewed international scientific journals (using the PubMed/MEDLINE and Addiction GWAS Resource databases) in which a significant association was reported. A total of 371 studies fit the search criteria. We then filtered SNPs with at least one replication study and performed meta-analysis of the significance of the associations. SNPs in the alcohol metabolizing genes, in the cholinergic gene cluster CHRNA5-CHRNA3-CHRNB4, and in the DRD2 and ANNK1 genes, are, to date, the most replicated and significant gene variants associated with alcohol- and nicotine-related phenotypes. In the case of cannabis and cocaine, a far fewer number of studies and replications have been reported, indicating either a need for further investigation or that the genetics of cannabis/cocaine addiction are more elusive. This review brings a global state-of-the-art vision of the behavioral genetics of addiction and collaborates on formulation of new hypothesis to guide future work.
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Affiliation(s)
- Kora-Mareen Bühler
- Department of Psychobiology; School of Psychology; Complutense University of Madrid; Málaga Spain
| | - Elena Giné
- Department of Cellular Biology; School of Medicine; Complutense University of Madrid; Málaga Spain
| | - Victor Echeverry-Alzate
- Department of Psychobiology; School of Psychology; Complutense University of Madrid; Málaga Spain
| | - Javier Calleja-Conde
- Department of Psychobiology; School of Psychology; Complutense University of Madrid; Málaga Spain
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8
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Grotewiel M, Bettinger JC. Drosophila and Caenorhabditis elegans as Discovery Platforms for Genes Involved in Human Alcohol Use Disorder. Alcohol Clin Exp Res 2015; 39:1292-311. [PMID: 26173477 PMCID: PMC4656040 DOI: 10.1111/acer.12785] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 05/18/2015] [Indexed: 01/08/2023]
Abstract
BACKGROUND Despite the profound clinical significance and strong heritability of alcohol use disorder (AUD), we do not yet have a comprehensive understanding of the naturally occurring genetic variance within the human genome that drives its development. This lack of understanding is likely to be due in part to the large phenotypic and genetic heterogeneities that underlie human AUD. As a complement to genetic studies in humans, many laboratories are using the invertebrate model organisms (iMOs) Drosophila melanogaster (fruit fly) and Caenorhabditis elegans (nematode worm) to identify genetic mechanisms that influence the effects of alcohol (ethanol) on behavior. While these extremely powerful models have identified many genes that influence the behavioral responses to alcohol, in most cases it has remained unclear whether results from behavioral-genetic studies in iMOs are directly applicable to understanding the genetic basis of human AUD. METHODS In this review, we critically evaluate the utility of the fly and worm models for identifying genes that influence AUD in humans. RESULTS Based on results published through early 2015, studies in flies and worms have identified 91 and 50 genes, respectively, that influence 1 or more aspects of behavioral responses to alcohol. Collectively, these fly and worm genes correspond to 293 orthologous genes in humans. Intriguingly, 51 of these 293 human genes have been implicated in AUD by at least 1 study in human populations. CONCLUSIONS Our analyses strongly suggest that the Drosophila and C. elegans models have considerable utility for identifying orthologs of genes that influence human AUD.
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Affiliation(s)
- Mike Grotewiel
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
- Virginia Commonwealth University Alcohol Research Center, Richmond, Virginia
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology , Virginia Commonwealth University, Richmond, Virginia
- Virginia Commonwealth University Alcohol Research Center, Richmond, Virginia
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9
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Pharmacotherapy for alcohol dependence: A stratified approach. Pharmacol Ther 2015; 153:10-24. [PMID: 25985735 DOI: 10.1016/j.pharmthera.2015.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 05/07/2015] [Indexed: 12/20/2022]
Abstract
Alcohol dependence is a common disorder in many societies worldwide, and remains difficult to identify and treat. It is also a risk factor for many secondary non-communicable diseases. Pharmacotherapy is one available treatment option, but appears to be underutilised in practice. Major barriers to use of medications in this area include lack of clinical guidance and questionable efficacy. However, for each medication there appears to be a subpopulation that responds positively, and understanding the moderating factors to treatment efficacy is an important research goal. Thus, this review provides a narrative regarding potential stratification techniques in pharmacological treatment of alcohol dependence, with a specific focus on typologies and pharmacogenetics. In addition, we discuss the basic background of stratified medicine and recent studies on genetic predisposition to alcohol dependence. A growing repository of data exists for both approved and non-approved pharmacotherapies, but failure to replicate findings, inadequate sample sizes, and insufficient funding has resulted in a translational gap. Implementing evidence-based stratified/personalised therapy and identifying new therapeutic agents may lead to improved clinical outcomes and reduced financial burden. Despite some promising findings to date, much work is still required.
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10
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ZUO L, ZHANG CK, SAYWARD FG, CHEUNG KH, WANG K, KRYSTAL JH, ZHAO H, LUO X. Gene-based and pathway-based genome-wide association study of alcohol dependence. SHANGHAI ARCHIVES OF PSYCHIATRY 2015; 27:111-8. [PMID: 26120261 PMCID: PMC4466852 DOI: 10.11919/j.issn.1002-0829.215031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 03/23/2015] [Indexed: 11/03/2022]
Abstract
BACKGROUND The organization of risk genes within signaling pathways may provide clues about the converging neurobiological effects of risk genes for alcohol dependence. AIM Identify risk genes and risk gene pathways for alcohol dependence. METHODS We conducted a pathway-based genome-wide association study (GWAS) of alcohol dependence using a gene-set-rich analytic approach. Approximately one million genetic markers were tested in the discovery sample which included 1409 European-American (EA) alcohol dependent individuals and 1518 EA healthy comparison subjects. An additional 681 African-American (AA) cases and 508 AA healthy subjects served as the replication sample. RESULTS We identified several genome-wide replicable risk genes and risk pathways that were significantly associated with alcohol dependence. After applying the Bonferroni correction for multiple testing, the 'cellextracellular matrix interactions' pathway (p<2.0E-4 in EAs) and the PXN gene (which encodes paxillin) (p=3.9E-7 in EAs) within this pathway were the most promising risk factors for alcohol dependence. There were also two nominally replicable pathways enriched in alcohol dependence-related genes in both EAs (0.015≤p≤0.035) and AAs (0.025≤p≤0.050): the 'Na+/Cl- dependent neurotransmitter transporters' pathway and the 'other glycan degradation' pathway. CONCLUSION These findings provide new evidence highlighting several genes and biological signaling processes that may be related to the risk for alcohol dependence.
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Affiliation(s)
- Lingjun ZUO
- Department of Psychiatry, Yale University School of
Medicine, New Haven, CT, United States
| | - Clarence K. ZHANG
- Department of Epidemiology and Public Health, Yale
University School of Medicine, New Haven, CT, United States
- Biostatistics Resource, Keck Laboratory, Department of
Genetics, Yale University School of Medicine, New Haven, CT, United States
| | - Frederick G. SAYWARD
- Center for Medical Informatics, Yale University School of
Medicine, New Haven, CT, United States
- Cooperative Studies Program Coordinating Center, VA
Connecticut Healthcare System, West Haven, CT, United States
| | - Kei-Hoi CHEUNG
- Center for Medical Informatics, Yale University School of
Medicine, New Haven, CT, United States
| | - Kesheng WANG
- Department of Biostatistics and Epidemiology, College of
Public Health, East Tennessee State University, Johnson City, TN, United
States
| | - John H. KRYSTAL
- Department of Psychiatry, Yale University School of
Medicine, New Haven, CT, United States
| | - Hongyu ZHAO
- Department of Epidemiology and Public Health, Yale
University School of Medicine, New Haven, CT, United States
| | - Xingguang LUO
- Department of Psychiatry, Yale University School of
Medicine, New Haven, CT, United States
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11
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Buisman-Pijlman FTA, Sumracki NM, Gordon JJ, Hull PR, Carter CS, Tops M. Individual differences underlying susceptibility to addiction: Role for the endogenous oxytocin system. Pharmacol Biochem Behav 2013; 119:22-38. [PMID: 24056025 DOI: 10.1016/j.pbb.2013.09.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 08/12/2013] [Accepted: 09/10/2013] [Indexed: 11/29/2022]
Abstract
Recent research shows that the effects of oxytocin are more diverse than initially thought and that in some cases oxytocin can directly influence the response to drugs and alcohol. Large individual differences in basal oxytocin levels and reactivity of the oxytocin system exist. This paper will review the literature to explore how individual differences in the oxytocin system arise and examine the hypothesis that this may mediate some of the individual differences in susceptibility to addiction and relapse. Differences in the oxytocin system can be based on individual factors, e.g. genetic variation especially in the oxytocin receptor, age or gender, or be the result of early environmental influences such as social experiences, stress or trauma. The paper addresses the factors that cause individual differences in the oxytocin system and the environmental factors that have been identified to induce long-term changes in the developing oxytocin system during different life phases. Individual differences in the oxytocin system can influence effects of drugs and alcohol directly or indirectly. The oxytocin system has bidirectional interactions with the stress-axis, autonomic nervous system, neurotransmitter systems (e.g. dopamine, serotonin and GABA/glutamate) and the immune system. These systems are all important, even vital, in different phases of addiction. It is suggested that early life adversity can change the development of the oxytocin system and the way it modulates other systems. This in turn could minimise the negative feedback loops that would normally exist. Individuals may show only minor differences in behaviour and function unless subsequent stressors or drug use challenges the system. It is postulated that at that time individual differences in oxytocin levels, reactivity of the system or interactions with other systems can influence general resilience, drug effects and the susceptibility to develop problematic drug and alcohol use.
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Affiliation(s)
| | - Nicole M Sumracki
- Discipline of Pharmacology, The University of Adelaide, Adelaide, SA 5005, Australia.
| | - Jake J Gordon
- Discipline of Pharmacology, The University of Adelaide, Adelaide, SA 5005, Australia.
| | - Philip R Hull
- Discipline of Pharmacology, The University of Adelaide, Adelaide, SA 5005, Australia.
| | - C Sue Carter
- Department of Psychiatry, University of North Carolina, Chapel Hill 27599, USA.
| | - Mattie Tops
- Department of Clinical Psychology, VU University Amsterdam, van der Boechorststraat 1, NL-1081 BT Amsterdam, The Netherlands.
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Agrawal A, Verweij KJH, Gillespie NA, Heath AC, Lessov-Schlaggar CN, Martin NG, Nelson EC, Slutske WS, Whitfield JB, Lynskey MT. The genetics of addiction-a translational perspective. Transl Psychiatry 2012; 2:e140. [PMID: 22806211 PMCID: PMC3410620 DOI: 10.1038/tp.2012.54] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 05/30/2012] [Indexed: 12/16/2022] Open
Abstract
Addictions are serious and common psychiatric disorders, and are among the leading contributors to preventable death. This selective review outlines and highlights the need for a multi-method translational approach to genetic studies of these important conditions, including both licit (alcohol, nicotine) and illicit (cannabis, cocaine, opiates) drug addictions and the behavioral addiction of disordered gambling. First, we review existing knowledge from twin studies that indicates both the substantial heritability of substance-specific addictions and the genetic overlap across addiction to different substances. Next, we discuss the limited number of candidate genes which have shown consistent replication, and the implications of emerging genomewide association findings for the genetic architecture of addictions. Finally, we review the utility of extensions to existing methods such as novel phenotyping, including the use of endophenotypes, biomarkers and neuroimaging outcomes; emerging methods for identifying alternative sources of genetic variation and accompanying statistical methodologies to interpret them; the role of gene-environment interplay; and importantly, the potential role of genetic variation in suggesting new alternatives for treatment of addictions.
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Affiliation(s)
- A Agrawal
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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13
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Wolen AR. Identifying gene networks underlying the neurobiology of ethanol and alcoholism. Alcohol Res 2012; 34:306-17. [PMID: 23134046 PMCID: PMC3860407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
For complex disorders such as alcoholism, identifying the genes linked to these diseases and their specific roles is difficult. Traditional genetic approaches, such as genetic association studies (including genome-wide association studies) and analyses of quantitative trait loci (QTLs) in both humans and laboratory animals already have helped identify some candidate genes. However, because of technical obstacles, such as the small impact of any individual gene, these approaches only have limited effectiveness in identifying specific genes that contribute to complex diseases. The emerging field of systems biology, which allows for analyses of entire gene networks, may help researchers better elucidate the genetic basis of alcoholism, both in humans and in animal models. Such networks can be identified using approaches such as high-throughput molecular profiling (e.g., through microarray-based gene expression analyses) or strategies referred to as genetical genomics, such as the mapping of expression QTLs (eQTLs). Characterization of gene networks can shed light on the biological pathways underlying complex traits and provide the functional context for identifying those genes that contribute to disease development.
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