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Nguyen H, Glaaser IW, Slesinger PA. Direct modulation of G protein-gated inwardly rectifying potassium (GIRK) channels. Front Physiol 2024; 15:1386645. [PMID: 38903913 PMCID: PMC11187414 DOI: 10.3389/fphys.2024.1386645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/08/2024] [Indexed: 06/22/2024] Open
Abstract
Ion channels play a pivotal role in regulating cellular excitability and signal transduction processes. Among the various ion channels, G-protein-coupled inwardly rectifying potassium (GIRK) channels serve as key mediators of neurotransmission and cellular responses to extracellular signals. GIRK channels are members of the larger family of inwardly-rectifying potassium (Kir) channels. Typically, GIRK channels are activated via the direct binding of G-protein βγ subunits upon the activation of G-protein-coupled receptors (GPCRs). GIRK channel activation requires the presence of the lipid signaling molecule, phosphatidylinositol 4,5-bisphosphate (PIP2). GIRK channels are also modulated by endogenous proteins and other molecules, including RGS proteins, cholesterol, and SNX27 as well as exogenous compounds, such as alcohol. In the last decade or so, several groups have developed novel drugs and small molecules, such as ML297, GAT1508 and GiGA1, that activate GIRK channels in a G-protein independent manner. Here, we aim to provide a comprehensive overview focusing on the direct modulation of GIRK channels by G-proteins, PIP2, cholesterol, and novel modulatory compounds. These studies offer valuable insights into the underlying molecular mechanisms of channel function, and have potential implications for both basic research and therapeutic development.
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Affiliation(s)
| | | | - Paul A. Slesinger
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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2
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Prytkova I, Liu Y, Fernando M, Gameiro-Ros I, Popova D, Kamarajan C, Xuei X, Chorlian DB, Edenberg HJ, Tischfield JA, Porjesz B, Pang ZP, Hart RP, Goate A, Slesinger PA. Upregulated GIRK2 Counteracts Ethanol-Induced Changes in Excitability and Respiration in Human Neurons. J Neurosci 2024; 44:e0918232024. [PMID: 38350999 PMCID: PMC11026340 DOI: 10.1523/jneurosci.0918-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 01/05/2024] [Accepted: 01/11/2024] [Indexed: 02/17/2024] Open
Abstract
Genome-wide association studies (GWAS) of electroencephalographic endophenotypes for alcohol use disorder (AUD) has identified noncoding polymorphisms within the KCNJ6 gene. KCNJ6 encodes GIRK2, a subunit of a G-protein-coupled inwardly rectifying potassium channel that regulates neuronal excitability. We studied the effect of upregulating KCNJ6 using an isogenic approach with human glutamatergic neurons derived from induced pluripotent stem cells (male and female donors). Using multielectrode arrays, population calcium imaging, single-cell patch-clamp electrophysiology, and mitochondrial stress tests, we find that elevated GIRK2 acts in concert with 7-21 d of ethanol exposure to inhibit neuronal activity, to counteract ethanol-induced increases in glutamate response, and to promote an increase intrinsic excitability. Furthermore, elevated GIRK2 prevented ethanol-induced changes in basal and activity-dependent mitochondrial respiration. These data support a role for GIRK2 in mitigating the effects of ethanol and a previously unknown connection to mitochondrial function in human glutamatergic neurons.
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Affiliation(s)
- Iya Prytkova
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Yiyuan Liu
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Michael Fernando
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Isabel Gameiro-Ros
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Dina Popova
- Human Genetics Institute, Rutgers University, Piscataway, New Jersey 08854
| | - Chella Kamarajan
- Department of Psychiatry & Behavioral Sciences, SUNY Downstate Health Sciences University, Brooklyn, New York 11203
| | - Xiaoling Xuei
- Departments of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - David B Chorlian
- Department of Psychiatry & Behavioral Sciences, SUNY Downstate Health Sciences University, Brooklyn, New York 11203
| | - Howard J Edenberg
- Departments of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
- Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Jay A Tischfield
- Human Genetics Institute, Rutgers University, Piscataway, New Jersey 08854
| | - Bernice Porjesz
- Department of Psychiatry & Behavioral Sciences, SUNY Downstate Health Sciences University, Brooklyn, New York 11203
| | - Zhiping P Pang
- Human Genetics Institute, Rutgers University, Piscataway, New Jersey 08854
- Department of Neuroscience and Cell Biology and The Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| | - Ronald P Hart
- Human Genetics Institute, Rutgers University, Piscataway, New Jersey 08854
- Department of Cell Biology & Neuroscience, Rutgers University, Piscataway, New Jersey 08854
| | - Alison Goate
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Paul A Slesinger
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
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Popova D, Sun J, Chow HM, Hart RP. A critical review of ethanol effects on neuronal firing: A metabolic perspective. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2024; 48:450-458. [PMID: 38217065 DOI: 10.1111/acer.15266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 12/22/2023] [Accepted: 01/02/2024] [Indexed: 01/14/2024]
Abstract
Ethanol metabolism is relatively understudied in neurons, even though changes in neuronal metabolism are known to affect their activity. Recent work demonstrates that ethanol is preferentially metabolized over glucose as a source of carbon and energy, and it reprograms neurons to a state of reduced energy potential and diminished capacity to utilize glucose once ethanol is exhausted. Ethanol intake has been associated with changes in neuronal firing and specific brain activity (EEG) patterns have been linked with risk for alcohol use disorder (AUD). Furthermore, a haplotype of the inwardly rectifying potassium channel subunit, GIRK2, which plays a critical role in regulating excitability of neurons, has been linked with AUD and shown to be directly regulated by ethanol. At the same time, overexpression of GIRK2 prevents ethanol-induced metabolic changes. Based on the available evidence, we conclude that the mechanisms underlying the effects of ethanol on neuronal metabolism are a novel target for developing therapies for AUD.
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Affiliation(s)
- Dina Popova
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, USA
| | - Jacquelyne Sun
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Hei-Man Chow
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, Hong Kong
- Gerald Choa Neuroscience Institute, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Ronald P Hart
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, USA
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4
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Prytkova I, Liu Y, Fernando M, Gameiro-Ros I, Popova D, Kamarajan C, Xuei X, Chorlian DB, Edenberg HJ, Tischfield JA, Porjesz B, Pang ZP, Hart RP, Goate A, Slesinger PA. Upregulated GIRK2 counteracts ethanol-induced changes in excitability & respiration in human neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.03.22.533236. [PMID: 36993693 PMCID: PMC10055374 DOI: 10.1101/2023.03.22.533236] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Genome-wide association analysis (GWAS) of electroencephalographic endophenotypes for alcohol use disorder (AUD) has identified non-coding polymorphisms within the KCNJ6 gene. KCNJ6 encodes GIRK2, a subunit of a G protein-coupled inwardly-rectifying potassium channel that regulates neuronal excitability. How changes in GIRK2 affect human neuronal excitability and the response to repeated ethanol exposure is poorly understood. Here, we studied the effect of upregulating KCNJ6 using an isogenic approach with human glutamatergic neurons derived from induced pluripotent stem cells (male and female donors). Using multi-electrode-arrays, population calcium imaging, single-cell patch-clamp electrophysiology, and mitochondrial stress tests, we find that elevated GIRK2 acts in concert with 7-21 days of ethanol exposure to inhibit neuronal activity, to counteract ethanol-induced increases in glutamate response, and to promote an increase intrinsic excitability. Furthermore, elevated GIRK2 prevented ethanol-dependent changes in basal and activity-dependent mitochondrial respiration. These data support a role for GIRK2 in mitigating the effects of ethanol and a previously unknown connection to mitochondrial function in human glutamatergic neurons. SIGNIFICANCE STATEMENT Alcohol use disorder (AUD) is a major health problem that has worsened since COVID, affecting over 100 million people worldwide. While it is known that heritability contributes to AUD, specific genes and their role in neuronal function remain poorly understood, especially in humans. In the current manuscript, we focused on the inwardly-rectifying potassium channel GIRK2, which has been identified in an AUD-endophenotype genome-wide association study. We used human excitatory neurons derived from healthy donors to study the impact of GIRK2 expression. Our results reveal that elevated GIRK2 counteracts ethanol-induced increases in glutamate response and intracellular calcium, as well as deficits in activity-dependent mitochondrial respiration. The role of GIRK2 in mitigating ethanol-induced hyper-glutamatergic and mitochondrial offers therapeutic promise for treating AUD.
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Chorlian DB, Meyers JL, Manz N, Zhang J, Kamarajan C, Pandey A, Wang JC, Plawecki M, Edenberg H, Goate A, Tischfield J, Porjesz B. Genetic influences vary by age and sex: Trajectories of the association of cholinergic system variants and theta band event related oscillations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530318. [PMID: 36909650 PMCID: PMC10002625 DOI: 10.1101/2023.02.27.530318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
To characterize systemic changes in genetic effects on brain development, the age variation of the associations of cholinergic genetic variants and theta band event-related oscillations (EROs) was studied in a sample of 2140 adolescents and young adults, ages 12 to 25 from the COGA prospective study. The theta band EROs were elicited in visual and auditory oddball (target detection) tasks and measured by EEG recording. Associations were found to vary with age, sex, task modality (auditory or visual), and scalp locality. Seven of the twenty-one muscarinic and nicotinic cholinergic SNPs studied in the analysis, from CHRM2, CHRNA3, CHRNA5, and CHRNB4, had significant effects on theta band EROs with considerable age spans for some sex-modality combination. No SNP-age-modality combination had significant effects in the same direction for males and females. Results suggest that nicotinic receptor associations are stronger before age 18, while muscarinic receptor associations are stronger after age 18.
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Popova D, Gameiro-Ros I, Youssef MM, Zalamea P, Morris AD, Prytkova I, Jadali A, Kwan KY, Kamarajan C, Salvatore JE, Xuei X, Chorlian DB, Porjesz B, Kuperman S, Dick DM, Goate A, Edenberg HJ, Tischfield JA, Pang ZP, Slesinger PA, Hart RP. Alcohol reverses the effects of KCNJ6 (GIRK2) noncoding variants on excitability of human glutamatergic neurons. Mol Psychiatry 2023; 28:746-758. [PMID: 36207584 PMCID: PMC9542475 DOI: 10.1038/s41380-022-01818-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 01/19/2023]
Abstract
Synonymous and noncoding single nucleotide polymorphisms (SNPs) in the KCNJ6 gene, encoding G protein-gated inwardly rectifying potassium channel subunit 2 (GIRK2), have been linked with increased electroencephalographic frontal theta event-related oscillations (ERO) in subjects diagnosed with alcohol use disorder (AUD). To identify molecular and cellular mechanisms while retaining the appropriate genetic background, we generated induced excitatory glutamatergic neurons (iN) from iPSCs derived from four AUD-diagnosed subjects with KCNJ6 variants ("Affected: AF") and four control subjects without variants ("Unaffected: UN"). Neurons were analyzed for changes in gene expression, morphology, excitability and physiological properties. Single-cell RNA sequencing suggests that KCNJ6 AF variant neurons have altered patterns of synaptic transmission and cell projection morphogenesis. Results confirm that AF neurons express lower levels of GIRK2, have greater neurite area, and elevated excitability. Interestingly, exposure to intoxicating concentrations of ethanol induces GIRK2 expression and reverses functional effects in AF neurons. Ectopic overexpression of GIRK2 alone mimics the effect of ethanol to normalize induced excitability. We conclude that KCNJ6 variants decrease GIRK2 expression and increase excitability and that this effect can be minimized or reduced with ethanol.
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Affiliation(s)
- Dina Popova
- Human Genetics Institute, Rutgers University, Piscataway, NJ, USA
| | - Isabel Gameiro-Ros
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mark M Youssef
- Department of Cell Biology & Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Petronio Zalamea
- Human Genetics Institute, Rutgers University, Piscataway, NJ, USA
| | - Ayeshia D Morris
- Joint Program in Toxicology, Rutgers University, Piscataway, NJ, USA
| | - Iya Prytkova
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Azadeh Jadali
- Department of Cell Biology & Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Kelvin Y Kwan
- Department of Cell Biology & Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Chella Kamarajan
- Dept. of Psychiatry & Behavioral Sciences, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Jessica E Salvatore
- Department of Psychiatry, Rutgers Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
| | - Xiaoling Xuei
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - David B Chorlian
- Dept. of Psychiatry & Behavioral Sciences, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Bernice Porjesz
- Dept. of Psychiatry & Behavioral Sciences, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Samuel Kuperman
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Danielle M Dick
- Rutgers Addiction Research Center, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
| | - Alison Goate
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Howard J Edenberg
- Department of Biochemistry and Molecular Biology, Indiana Univ School of Medicine, Indianapolis, IN, USA
| | - Jay A Tischfield
- Human Genetics Institute, Rutgers University, Piscataway, NJ, USA
| | - Zhiping P Pang
- Human Genetics Institute, Rutgers University, Piscataway, NJ, USA
- Child Health Institute, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, USA
| | - Paul A Slesinger
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ronald P Hart
- Human Genetics Institute, Rutgers University, Piscataway, NJ, USA.
- Department of Cell Biology & Neuroscience, Rutgers University, Piscataway, NJ, USA.
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7
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Luo H, Marron Fernandez de Velasco E, Wickman K. Neuronal G protein-gated K + channels. Am J Physiol Cell Physiol 2022; 323:C439-C460. [PMID: 35704701 PMCID: PMC9362898 DOI: 10.1152/ajpcell.00102.2022] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels exert a critical inhibitory influence on neurons. Neuronal GIRK channels mediate the G protein-dependent, direct/postsynaptic inhibitory effect of many neurotransmitters including γ-aminobutyric acid (GABA), serotonin, dopamine, adenosine, somatostatin, and enkephalin. In addition to their complex regulation by G proteins, neuronal GIRK channel activity is sensitive to PIP2, phosphorylation, regulator of G protein signaling (RGS) proteins, intracellular Na+ and Ca2+, and cholesterol. The application of genetic and viral manipulations in rodent models, together with recent progress in the development of GIRK channel modulators, has increased our understanding of the physiological and behavioral impact of neuronal GIRK channels. Work in rodent models has also revealed that neuronal GIRK channel activity is modified, transiently or persistently, by various stimuli including exposure drugs of abuse, changes in neuronal activity patterns, and aversive experience. A growing body of preclinical and clinical evidence suggests that dysregulation of GIRK channel activity contributes to neurological diseases and disorders. The primary goals of this review are to highlight fundamental principles of neuronal GIRK channel biology, mechanisms of GIRK channel regulation and plasticity, the nascent landscape of GIRK channel pharmacology, and the potential relevance of GIRK channels to the pathophysiology and treatment of neurological diseases and disorders.
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Affiliation(s)
- Haichang Luo
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States
| | | | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States
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Meyers JL, Zhang J, Chorlian DB, Pandey AK, Kamarajan C, Wang JC, Wetherill L, Lai D, Chao M, Chan G, Kinreich S, Kapoor M, Bertelsen S, McClintick J, Bauer L, Hesselbrock V, Kuperman S, Kramer J, Salvatore JE, Dick DM, Agrawal A, Foroud T, Edenberg HJ, Goate A, Porjesz B. A genome-wide association study of interhemispheric theta EEG coherence: implications for neural connectivity and alcohol use behavior. Mol Psychiatry 2021; 26:5040-5052. [PMID: 32433515 PMCID: PMC8503860 DOI: 10.1038/s41380-020-0777-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/14/2020] [Accepted: 05/04/2020] [Indexed: 12/23/2022]
Abstract
Aberrant connectivity of large-scale brain networks has been observed among individuals with alcohol use disorders (AUDs) as well as in those at risk, suggesting deficits in neural communication between brain regions in the liability to develop AUD. Electroencephalographical (EEG) coherence, which measures the degree of synchrony between brain regions, may be a useful measure of connectivity patterns in neural networks for studying the genetics of AUD. In 8810 individuals (6644 of European and 2166 of African ancestry) from the Collaborative Study on the Genetics of Alcoholism (COGA), we performed a Multi-Trait Analyses of genome-wide association studies (MTAG) on parietal resting-state theta (3-7 Hz) EEG coherence, which previously have been associated with AUD. We also examined developmental effects of GWAS findings on trajectories of neural connectivity in a longitudinal subsample of 2316 adolescent/young adult offspring from COGA families (ages 12-30) and examined the functional and clinical significance of GWAS variants. Six correlated single nucleotide polymorphisms located in a brain-expressed lincRNA (ENSG00000266213) on chromosome 18q23 were associated with posterior interhemispheric low theta EEG coherence (3-5 Hz). These same variants were also associated with alcohol use behavior and posterior corpus callosum volume, both in a subset of COGA and in the UK Biobank. Analyses in the subsample of COGA offspring indicated that the association of rs12954372 with low theta EEG coherence occurred only in females, most prominently between ages 25 and 30 (p < 2 × 10-9). Converging data provide support for the role of genetic variants on chromosome 18q23 in regulating neural connectivity and alcohol use behavior, potentially via dysregulated myelination. While findings were less robust, genome-wide associations were also observed with rs151174000 and parieto-frontal low theta coherence, rs14429078 and parieto-occipital interhemispheric high theta coherence, and rs116445911 with centro-parietal low theta coherence. These novel genetic findings highlight the utility of the endophenotype approach in enhancing our understanding of mechanisms underlying addiction susceptibility.
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Affiliation(s)
- Jacquelyn L Meyers
- Department of Psychiatry and the Henri Begleiter Neurodynamics Laboratory, State University of New York Downstate Medical Center, Brooklyn, NY, 11203, USA.
| | - Jian Zhang
- Department of Psychiatry and the Henri Begleiter Neurodynamics Laboratory, State University of New York Downstate Medical Center, Brooklyn, NY, 11203, USA
| | - David B Chorlian
- Department of Psychiatry and the Henri Begleiter Neurodynamics Laboratory, State University of New York Downstate Medical Center, Brooklyn, NY, 11203, USA
| | - Ashwini K Pandey
- Department of Psychiatry and the Henri Begleiter Neurodynamics Laboratory, State University of New York Downstate Medical Center, Brooklyn, NY, 11203, USA
| | - Chella Kamarajan
- Department of Psychiatry and the Henri Begleiter Neurodynamics Laboratory, State University of New York Downstate Medical Center, Brooklyn, NY, 11203, USA
| | - Jen-Chyong Wang
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Leah Wetherill
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Dongbing Lai
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Michael Chao
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Grace Chan
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - Sivan Kinreich
- Department of Psychiatry and the Henri Begleiter Neurodynamics Laboratory, State University of New York Downstate Medical Center, Brooklyn, NY, 11203, USA
| | - Manav Kapoor
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Sarah Bertelsen
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Jeanette McClintick
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Lance Bauer
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - Victor Hesselbrock
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - Samuel Kuperman
- Department of Psychiatry, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - John Kramer
- Department of Psychiatry, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Jessica E Salvatore
- Department of Psychology and the Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Danielle M Dick
- Department of Psychology and the Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Arpana Agrawal
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Tatiana Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Howard J Edenberg
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Alison Goate
- Departments of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Departments of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Bernice Porjesz
- Department of Psychiatry and the Henri Begleiter Neurodynamics Laboratory, State University of New York Downstate Medical Center, Brooklyn, NY, 11203, USA
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9
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Alcohol. Alcohol 2021. [DOI: 10.1016/b978-0-12-816793-9.00001-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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10
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Ziegler GC, Röser C, Renner T, Hahn T, Ehlis AC, Weber H, Dempfle A, Walitza S, Jacob C, Romanos M, Fallgatter AJ, Reif A, Lesch KP. KCNJ6 variants modulate reward-related brain processes and impact executive functions in attention-deficit/hyperactivity disorder. Am J Med Genet B Neuropsychiatr Genet 2020; 183:247-257. [PMID: 31099984 DOI: 10.1002/ajmg.b.32734] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 04/04/2019] [Accepted: 05/06/2019] [Indexed: 12/18/2022]
Abstract
KCNJ6, encoding a potassium channel subunit, regulates the excitability of dopaminergic neurons and is expressed in attention-deficit/hyperactivity disorder (ADHD)-relevant brain regions. As a potential ADHD risk gene, KCNJ6, therefore, may contribute to the endophenotypic variation of the disorder. The impact of two SNPs, rs7275707 and rs6517442, both located in the transcriptional control region of KCNJ6, on reporter gene expression was explored in cultured cells. The KCNJ6 variants were then tested for association with ADHD and personality traits in a family-based sample (165 affected children) and an adult case-control sample (450 patients, 426 controls). Furthermore, the genotypic influence on performance in an n-back task and a cued continuous performance test (cCPT) was investigated by electroencephalography recordings. Finally, rs6517442 function was assessed by a reward anticipation paradigm using functional magnetic resonance imaging. Different haplotypes of rs7275707 and rs6517442 significantly influenced KCNJ6 gene expression proving their functional relevance on the molecular level. In the family-based children sample rs7275707 was associated with ADHD (p = .038). Moreover, rs7275707 showed association with the personality trait of Reward Dependence (p = .031). In the ADHD group, both rs7275707 and rs6517442 influenced the Go-centroid location in the cCPT and the N200 amplitude in the n-back task. Furthermore, ventral striatal activation was impacted by rs6517442 during reward anticipation. Our data indicate that functional variants of KCNJ6 influence brain activity during reward-related and executive processes supporting the view of a differential, age-dependent modulatory impact of dopamine-related brain processes in ADHD risk.
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Affiliation(s)
- Georg C Ziegler
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany
| | - Christoph Röser
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany
| | - Tobias Renner
- Department of Child and Adolescent Psychiatry, University of Tübingen, Tübingen, Germany
| | - Tim Hahn
- Department of Psychiatry and Psychotherapy, University of Münster, Münster, Germany
| | - Ann-Christine Ehlis
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Heike Weber
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany
| | - Astrid Dempfle
- Institute of Medical Biometry and Statistics, Christian Albrecht-University Kiel, Kiel, Germany
| | - Susanne Walitza
- Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Christian Jacob
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany.,Department of Psychiatry and Psychotherapy, Medius Hospital of Kirchheim, Kirchheim unter Teck, Germany
| | - Marcel Romanos
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Andreas J Fallgatter
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Andreas Reif
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany.,Department of Psychiatry and Psychotherapy, University of Frankfurt, Frankfurt, Germany
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, ADHD Clinical Research Unit, Laboratory of Translational Neuroscience, Center of Mental Health, University of Würzburg, Würzburg, Germany.,Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.,Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
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11
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Prefrontal-hippocampal functional connectivity encodes recognition memory and is impaired in intellectual disability. Proc Natl Acad Sci U S A 2020; 117:11788-11798. [PMID: 32393630 DOI: 10.1073/pnas.1921314117] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Down syndrome (DS) is the most common form of intellectual disability. The cognitive alterations in DS are thought to depend on brain regions critical for learning and memory such as the prefrontal cortex (PFC) and the hippocampus (HPC). Neuroimaging studies suggest that increased brain connectivity correlates with lower intelligence quotients (IQ) in individuals with DS; however, its contribution to cognitive impairment is unresolved. We recorded neural activity in the PFC and HPC of the trisomic Ts65Dn mouse model of DS during quiet wakefulness, natural sleep, and the performance of a memory test. During rest, trisomic mice showed increased theta oscillations and cross-frequency coupling in the PFC and HPC while prefrontal-hippocampal synchronization was strengthened, suggesting hypersynchronous local and cross-regional processing. During sleep, slow waves were reduced, and gamma oscillations amplified in Ts65Dn mice, likely reflecting prolonged light sleep. Moreover, hippocampal sharp-wave ripples were disrupted, which may have further contributed to deficient memory consolidation. Memory performance in euploid mice correlated strongly with functional connectivity measures that indicated a hippocampal control over memory acquisition and retrieval at theta and gamma frequencies, respectively. By contrast, trisomic mice exhibited poor memory abilities and disordered prefrontal-hippocampal functional connectivity. Memory performance and key neurophysiological alterations were rescued after 1 month of chronic administration of a green tea extract containing epigallocatequin-3-gallate (EGCG), which improves executive function in young adults with DS and Ts65Dn mice. Our findings suggest that abnormal prefrontal-hippocampal circuit dynamics are candidate neural mechanisms for memory impairment in DS.
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12
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Wang H, Vanyukov MM, Xing EP, Wu W. Discovering weaker genetic associations guided by known associations. BMC Med Genomics 2020; 13:19. [PMID: 32093702 PMCID: PMC7038505 DOI: 10.1186/s12920-020-0667-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 01/20/2020] [Indexed: 12/05/2022] Open
Abstract
Background The current understanding of the genetic basis of complex human diseases is that they are caused and affected by many common and rare genetic variants. A considerable number of the disease-associated variants have been identified by Genome Wide Association Studies, however, they can explain only a small proportion of heritability. One of the possible reasons for the missing heritability is that many undiscovered disease-causing variants are weakly associated with the disease. This can pose serious challenges to many statistical methods, which seems to be only capable of identifying disease-associated variants with relatively stronger coefficients. Results In order to help identify weaker variants, we propose a novel statistical method, Constrained Sparse multi-locus Linear Mixed Model (CS-LMM) that aims to uncover genetic variants of weaker associations by incorporating known associations as a prior knowledge in the model. Moreover, CS-LMM accounts for polygenic effects as well as corrects for complex relatednesses. Our simulation experiments show that CS-LMM outperforms other competing existing methods in various settings when the combinations of MAFs and coefficients reflect different scenarios in complex human diseases. Conclusions We also apply our method to the GWAS data of alcoholism and Alzheimer’s disease and exploratively discover several SNPs. Many of these discoveries are supported through literature survey. Furthermore, our association results strengthen the belief in genetic links between alcoholism and Alzheimer’s disease.
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Affiliation(s)
- Haohan Wang
- Language Technologies Institute, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Michael M Vanyukov
- Department of Pharmaceutical Sciences, Departments of Psychiatry, and Human Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eric P Xing
- Language Technologies Institute, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA.,Machine Learning Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Wei Wu
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA.
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13
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Meyers JL, Chorlian DB, Johnson EC, Pandey AK, Kamarajan C, Salvatore JE, Aliev F, Subbie-Saenz de Viteri S, Zhang J, Chao M, Kapoor M, Hesselbrock V, Kramer J, Kuperman S, Nurnberger J, Tischfield J, Goate A, Foroud T, Dick DM, Edenberg HJ, Agrawal A, Porjesz B. Association of Polygenic Liability for Alcohol Dependence and EEG Connectivity in Adolescence and Young Adulthood. Brain Sci 2019; 9:E280. [PMID: 31627376 PMCID: PMC6826735 DOI: 10.3390/brainsci9100280] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/27/2019] [Accepted: 10/04/2019] [Indexed: 12/13/2022] Open
Abstract
Differences in the connectivity of large-scale functional brain networks among individuals with alcohol use disorders (AUD), as well as those at risk for AUD, point to dysfunctional neural communication and related cognitive impairments. In this study, we examined how polygenic risk scores (PRS), derived from a recent GWAS of DSM-IV Alcohol Dependence (AD) conducted by the Psychiatric Genomics Consortium, relate to longitudinal measures of interhemispheric and intrahemispheric EEG connectivity (alpha, theta, and beta frequencies) in adolescent and young adult offspring from the Collaborative Study on the Genetics of Alcoholism (COGA) assessed between ages 12 and 31. Our findings indicate that AD PRS (p-threshold < 0.001) was associated with increased fronto-central, tempo-parietal, centro-parietal, and parietal-occipital interhemispheric theta and alpha connectivity in males only from ages 18-31 (beta coefficients ranged from 0.02-0.06, p-values ranged from 10-6-10-12), but not in females. Individuals with higher AD PRS also demonstrated more performance deficits on neuropsychological tasks (Tower of London task, visual span test) as well as increased risk for lifetime DSM-5 alcohol and opioid use disorders. We conclude that measures of neural connectivity, together with neurocognitive performance and substance use behavior, can be used to further understanding of how genetic risk variants from large GWAS of AUD may influence brain function. In addition, these data indicate the importance of examining sex and developmental effects, which otherwise may be masked. Understanding of neural mechanisms linking genetic variants emerging from GWAS to risk for AUD throughout development may help to identify specific points when neurocognitive prevention and intervention efforts may be most effective.
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Affiliation(s)
- Jacquelyn L Meyers
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
| | - David B Chorlian
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
| | - Emma C Johnson
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Ashwini K Pandey
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
| | - Chella Kamarajan
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
| | - Jessica E Salvatore
- Department of Psychology, Virginia Commonwealth University, Richmond, VA 23284, USA.
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - Fazil Aliev
- Department of Psychology, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | | | - Jian Zhang
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
| | - Michael Chao
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Manav Kapoor
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Victor Hesselbrock
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT 06030, USA.
| | - John Kramer
- Department of Psychiatry, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
| | - Samuel Kuperman
- Department of Psychiatry, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
| | - John Nurnberger
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
| | - Jay Tischfield
- Department of Genetics and the Human Genetics Institute of New Jersey, Rutgers University, Newark, NJ 08901, USA.
| | - Alison Goate
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Tatiana Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
| | - Danielle M Dick
- Department of Psychology, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - Howard J Edenberg
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Arpana Agrawal
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Bernice Porjesz
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
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14
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Genetic loci for alcohol-related life events and substance-induced affective symptoms: indexing the "dark side" of addiction. Transl Psychiatry 2019; 9:71. [PMID: 30718457 PMCID: PMC6362044 DOI: 10.1038/s41398-019-0397-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 01/17/2019] [Indexed: 12/24/2022] Open
Abstract
A limited number of genetic variants have been identified in traditional GWAS as risk or protective factors for alcohol use disorders (AUD) and related phenotypes. We herein report whole-genome association and rare-variant analyses on AUD traits in American Indians (AI) and European Americans (EA). We evaluated 742 AIs and 1711 EAs using low-coverage whole-genome sequencing. Phenotypes included: (1) a metric based on the occurrence of 36 alcohol-related life events that reflect AUD severity; (2) two alcohol-induced affective symptoms that accompany severe AUDs. We identified two new loci for alcohol-related life events with converging evidence from both cohorts: rare variants of K2P channel gene KCNK2, and rare missense and splice-site variants in pro-inflammatory mediator gene PDE4C. A NAF1-FSTL5 intergenic variant and an FSTL5 variant were respectively associated with alcohol-related life events in AI and EA. PRKG2 of serine/threonine protein kinase family, and rare variants in interleukin subunit gene EBI3 (IL-27B) were uniquely associated with alcohol-induced affective symptoms in AI. LncRNA LINC02347 on 12q24.32 was uniquely associated with alcohol-induced depression in EA. The top GWAS findings were primarily rare/low-frequency variants in AI, and common variants in EA. Adrenal gland was the most enriched in tissue-specific gene expression analysis for alcohol-related life events, and nucleus accumbens was the most enriched for alcohol-induced affective states in AI. Prefrontal cortex was the most enriched in EA for both traits. These studies suggest that whole-genome sequencing can identify novel, especially uncommon, variants associated with severe AUD phenotypes although the findings may be population specific.
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15
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Cavanagh JF. Electrophysiology as a theoretical and methodological hub for the neural sciences. Psychophysiology 2019; 56:e13314. [PMID: 30556196 PMCID: PMC6687291 DOI: 10.1111/psyp.13314] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 11/21/2018] [Accepted: 11/23/2018] [Indexed: 12/12/2022]
Abstract
Electrophysiology is a direct measure of neuronal processes, and it is uniquely sensitive to canonical neural operations that underlie emergent psychological operations. These qualities make it well suited for discovery of aberrant neural mechanisms that underlie complicated disease states. This technique is routinely utilized in vitro, in vivo, and in outpatient neurological clinics, offering a translatable bridge between animal models and human patients. The bench-to-bedside potential of this approach is unparalleled, yet it also remains undeveloped due to the slow inertia of legacy techniques and interpretations. In this review, I discuss these strengths of the method, and I detail compelling reasons why future advancements can have a direct and tangible influence over clinical practice. I hope to motivate a blurring of traditional boundaries between preclinical, computational, imaging, and clinical fields by advancing electrophysiology as a common hub for methodological integration and theoretical advancement.
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Affiliation(s)
- James F Cavanagh
- Department of Psychology, University of New Mexico, Albuquerque, New Mexico
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16
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Prytkova I, Goate A, Hart RP, Slesinger PA. Genetics of Alcohol Use Disorder: A Role for Induced Pluripotent Stem Cells? Alcohol Clin Exp Res 2018; 42:1572-1590. [PMID: 29897633 PMCID: PMC6120805 DOI: 10.1111/acer.13811] [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: 03/06/2018] [Accepted: 06/04/2018] [Indexed: 12/13/2022]
Abstract
Alcohol use disorder (AUD) affects millions of people and costs nearly 250 billion dollars annually. Few effective FDA-approved treatments exist, and more are needed. AUDs have a strong heritability, but only a few genes have been identified with a large effect size on disease phenotype. Genomewide association studies (GWASs) have identified common variants with low effect sizes, most of which are in noncoding regions of the genome. Animal models frequently fail to recapitulate key molecular features of neuropsychiatric disease due to the polygenic nature of the disease, partial conservation of coding regions, and significant disparity in noncoding regions. By contrast, human induced pluripotent stem cells (hiPSCs) derived from patients provide a powerful platform for evaluating genes identified by GWAS and modeling complex interactions in the human genome. hiPSCs can be differentiated into a wide variety of human cells, including neurons, glia, and hepatic cells, which are compatible with numerous functional assays and genome editing techniques. In this review, we focus on current applications and future directions of patient hiPSC-derived central nervous system cells for modeling AUDs in addition to highlighting successful applications of hiPSCs in polygenic neuropsychiatric diseases.
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Affiliation(s)
- Iya Prytkova
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Alison Goate
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
- Ronald M. Loeb Center for Alzheimer’s disease, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Ronald P. Hart
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway NJ 08854, USA
| | - Paul A. Slesinger
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
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17
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Cannady R, Rinker JA, Nimitvilai S, Woodward JJ, Mulholland PJ. Chronic Alcohol, Intrinsic Excitability, and Potassium Channels: Neuroadaptations and Drinking Behavior. Handb Exp Pharmacol 2018; 248:311-343. [PMID: 29374839 DOI: 10.1007/164_2017_90] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Neural mechanisms underlying alcohol use disorder remain elusive, and this lack of understanding has slowed the development of efficacious treatment strategies for reducing relapse rates and prolonging abstinence. While synaptic adaptations produced by chronic alcohol exposure have been extensively characterized in a variety of brain regions, changes in intrinsic excitability of critical projection neurons are understudied. Accumulating evidence suggests that prolonged alcohol drinking and alcohol dependence produce plasticity of intrinsic excitability as measured by changes in evoked action potential firing and after-hyperpolarization amplitude. In this chapter, we describe functional changes in cell firing of projection neurons after long-term alcohol exposure that occur across species and in multiple brain regions. Adaptations in calcium-activated (KCa2), voltage-dependent (KV7), and G protein-coupled inwardly rectifying (Kir3 or GIRK) potassium channels that regulate the evoked firing and after-hyperpolarization parallel functional changes in intrinsic excitability induced by chronic alcohol. Moreover, there are strong genetic links between alcohol-related behaviors and genes encoding KCa2, KV7, and GIRK channels, and pharmacologically targeting these channels reduces alcohol consumption and alcohol-related behaviors. Together, these studies demonstrate that chronic alcohol drinking produces adaptations in KCa2, KV7, and GIRK channels leading to impaired regulation of the after-hyperpolarization and aberrant cell firing. Correcting the deficit in the after-hyperpolarization with positive modulators of KCa2 and KV7 channels and altering the GIRK channel binding pocket to block the access of alcohol represent a potentially highly effective pharmacological approach that can restore changes in intrinsic excitability and reduce alcohol consumption in affected individuals.
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Affiliation(s)
- Reginald Cannady
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA
| | - Jennifer A Rinker
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA
| | - Sudarat Nimitvilai
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA
| | - John J Woodward
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA
| | - Patrick J Mulholland
- Departments of Neuroscience and Psychiatry and Behavioral Sciences, Charleston Alcohol Research Center, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC, USA.
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18
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Peng Q, Schork NJ, Wilhelmsen KC, Ehlers CL. Whole genome sequence association and ancestry-informed polygenic profile of EEG alpha in a Native American population. Am J Med Genet B Neuropsychiatr Genet 2017; 174:435-450. [PMID: 28436151 PMCID: PMC5435561 DOI: 10.1002/ajmg.b.32533] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 02/06/2017] [Indexed: 12/18/2022]
Abstract
EEG alpha activity is the dominant oscillation in most adult humans, is highly heritable, and has been associated with a number of cognitive functions. Two EEG phenotypes, low- and high-voltage alpha (LVA & HVA), have been demonstrated to have high heritabilities. They have different prevalence depending on a population's ancestral origins. In the present study we assessed the influence of ancestry admixture on EEG alpha power, and conducted a whole genome sequencing association analysis and an ancestry-informed polygenic study on those phenotypes in a Native American (NA) population that has a high prevalence of LVA. Seven common variants, in LD with each other upstream from gene ASIC2, reached genome-wide significance (p = 2 × 10-8 ) having a positive association with alpha voltage. They had lower minor allele frequencies in the NAs than in a global population sample. Overall correlations between lower degrees of NA (higher degree European) ancestry and HVA, and higher degrees of NA and LVA were also found. Additionally a rare-variant gene-based study identified gene TIA1 being negatively associated with LVA. Approximately 3% of SNPs exhibited a 15-fold enrichment that explained nearly half of the total SNP-heritability for EEG alpha. These regions showed the most significant anti-correlations between NA ancestry and alpha voltage, and were enriched for genes and pathways mediating cognitive functions. Our findings suggested that these regions likely harbor causal variants for HVA, and lacking of such variants could explain the high prevalence of LVA in this NA population, possibly illuminating the ancestral origin and genetic basis for EEG alpha.
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Affiliation(s)
- Qian Peng
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California 92037 USA
- Department of Human Biology, J. Craig Venter Institute, La Jolla, California 92037 USA
| | - Nicholas J. Schork
- Department of Human Biology, J. Craig Venter Institute, La Jolla, California 92037 USA
| | - Kirk C. Wilhelmsen
- Department of Genetics and Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 USA
| | - Cindy L. Ehlers
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California 92037 USA
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19
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Kamarajan C, Pandey AK, Chorlian DB, Manz N, Stimus AT, Edenberg HJ, Wetherill L, Schuckit M, Wang JC, Kuperman S, Kramer J, Tischfield JA, Porjesz B. A KCNJ6 gene polymorphism modulates theta oscillations during reward processing. Int J Psychophysiol 2017; 115:13-23. [PMID: 27993610 PMCID: PMC5392377 DOI: 10.1016/j.ijpsycho.2016.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/09/2016] [Accepted: 12/15/2016] [Indexed: 12/16/2022]
Abstract
Event related oscillations (EROs) are heritable measures of neurocognitive function that have served as useful phenotype in genetic research. A recent family genome-wide association study (GWAS) by the Collaborative Study on the Genetics of Alcoholism (COGA) found that theta EROs during visual target detection were associated at genome-wide levels with several single nucleotide polymorphisms (SNPs), including a synonymous SNP, rs702859, in the KCNJ6 gene that encodes GIRK2, a G-protein inward rectifying potassium channel that regulates excitability of neuronal networks. The present study examined the effect of the KCNJ6 SNP (rs702859), previously associated with theta ERO to targets in a visual oddball task, on theta EROs during reward processing in a monetary gambling task. The participants were 1601 adolescent and young adult offspring within the age-range of 17-25years (800 males and 801 females) from high-dense alcoholism families as well as control families of the COGA prospective study. Theta ERO power (3.5-7.5Hz, 200-500ms post-stimulus) was compared across genotype groups. ERO theta power at central and parietal regions increased as a function of the minor allele (A) dose in the genotype (AA>AG>GG) in both loss and gain conditions. These findings indicate that variations in the KCNJ6 SNP influence magnitude of theta oscillations at posterior loci during the evaluation of loss and gain, reflecting a genetic influence on neuronal circuits involved in reward-processing. Increased theta power as a function of minor allele dose suggests more efficient cognitive processing in those carrying the minor allele of the KCNJ6 SNPs. Future studies are needed to determine the implications of these genetic effects on posterior theta EROs as possible "protective" factors, or as indices of delays in brain maturation (i.e., lack of frontalization).
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Affiliation(s)
- Chella Kamarajan
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | - Ashwini K Pandey
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - David B Chorlian
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Niklas Manz
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Arthur T Stimus
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | | | - Leah Wetherill
- Indiana University School of Medicine, Indianapolis, IN, USA
| | - Marc Schuckit
- University of California San Diego Medical Center, San Diego, CA, USA
| | | | | | | | | | - Bernice Porjesz
- Henri Begleiter Neurodynamics Lab, SUNY Downstate Medical Center, Brooklyn, NY, USA
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20
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Chorlian DB, Rangaswamy M, Manz N, Meyers JL, Kang SJ, Kamarajan C, Pandey AK, Wang JC, Wetherill L, Edenberg H, Porjesz B. Genetic correlates of the development of theta event related oscillations in adolescents and young adults. Int J Psychophysiol 2017; 115:24-39. [PMID: 27847216 PMCID: PMC5456461 DOI: 10.1016/j.ijpsycho.2016.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/18/2016] [Accepted: 11/08/2016] [Indexed: 12/22/2022]
Abstract
The developmental trajectories of theta band (4-7Hz) event-related oscillations (EROs), a key neurophysiological constituent of the P3 response, were assessed in 2170 adolescents and young adults ages 12 to 25. The theta EROs occurring in the P3 response, important indicators of neurocognitive function, were elicited during the evaluation of task-relevant target stimuli in visual and auditory oddball tasks. Associations between the theta EROs and genotypic variants of 4 KCNJ6 single nucleotide polymorphisms (SNPs) were found to vary with age, sex, scalp location, and task modality. Three of the four KCNJ6 SNPs studied here were found to be significantly associated with the same theta EROs in adults in a previous family genome wide association study. Since measures of the P3 response have been found to be a useful endophenotypes for the study of a number of clinical and behavioral disorders, studies of genetic effects on its development in adolescents and young adults may illuminate neurophysiological factors contributing to the onset of these conditions.
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Affiliation(s)
- David B Chorlian
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | | | - Niklas Manz
- Department of Physics, College of Wooster, Wooster, OH, USA
| | - Jacquelyn L Meyers
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Sun J Kang
- Stratton VA Medical Center, Albany, NY, USA
| | - Chella Kamarajan
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Ashwini K Pandey
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | | | - Leah Wetherill
- Indiana University School of Medicine, Indianapolis, IN, USA
| | - Howard Edenberg
- Indiana University School of Medicine, Indianapolis, IN, USA
| | - Bernice Porjesz
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA
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21
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Anokhin AP. The genetics of brain function and psychophysiology: An introduction to the special issue. Int J Psychophysiol 2017; 115:1-3. [PMID: 28259534 DOI: 10.1016/j.ijpsycho.2017.02.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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22
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Reilly MT, Noronha A, Goldman D, Koob GF. Genetic studies of alcohol dependence in the context of the addiction cycle. Neuropharmacology 2017; 122:3-21. [PMID: 28118990 DOI: 10.1016/j.neuropharm.2017.01.017] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 12/16/2022]
Abstract
Family, twin and adoption studies demonstrate clearly that alcohol dependence and alcohol use disorders are phenotypically complex and heritable. The heritability of alcohol use disorders is estimated at approximately 50-60% of the total phenotypic variability. Vulnerability to alcohol use disorders can be due to multiple genetic or environmental factors or their interaction which gives rise to extensive and daunting heterogeneity. This heterogeneity makes it a significant challenge in mapping and identifying the specific genes that influence alcohol use disorders. Genetic linkage and (candidate gene) association studies have been used now for decades to map and characterize genomic loci and genes that underlie the genetic vulnerability to alcohol use disorders. These approaches have been moderately successful in identifying several genes that contribute to the complexity of alcohol use disorders. Recently, genome-wide association studies have become one of the major tools for identifying genes for alcohol use disorders by examining correlations between millions of common single-nucleotide polymorphisms with diagnosis status. Genome-wide association studies are just beginning to uncover novel biology; however, the functional significance of results remains a matter of extensive debate and uncertainty. In this review, we present a select group of genome-wide association studies of alcohol dependence, as one example of a way to generate functional hypotheses, within the addiction cycle framework. This analysis may provide novel directions for validating the functional significance of alcohol dependence candidate genes. This article is part of the Special Issue entitled "Alcoholism".
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Affiliation(s)
- Matthew T Reilly
- National Institutes of Health (NIH), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Division of Neuroscience and Behavior, 5635 Fishers Lane, Bethesda, MD 20852, USA.
| | - Antonio Noronha
- National Institutes of Health (NIH), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Division of Neuroscience and Behavior, 5635 Fishers Lane, Bethesda, MD 20852, USA
| | - David Goldman
- National Institutes of Health (NIH), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Chief, Laboratory of Neurogenetics, 5635 Fishers Lane, Bethesda, MD 20852, USA
| | - George F Koob
- National Institutes of Health (NIH), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Director NIAAA, 5635 Fishers Lane, Bethesda, MD 20852, USA
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Iacono WG, Malone SM, Vrieze SI. Endophenotype best practices. Int J Psychophysiol 2017; 111:115-144. [PMID: 27473600 PMCID: PMC5219856 DOI: 10.1016/j.ijpsycho.2016.07.516] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/21/2016] [Accepted: 07/24/2016] [Indexed: 01/19/2023]
Abstract
This review examines the current state of electrophysiological endophenotype research and recommends best practices that are based on knowledge gleaned from the last decade of molecular genetic research with complex traits. Endophenotype research is being oversold for its potential to help discover psychopathology relevant genes using the types of small samples feasible for electrophysiological research. This is largely because the genetic architecture of endophenotypes appears to be very much like that of behavioral traits and disorders: they are complex, influenced by many variants (e.g., tens of thousands) within many genes, each contributing a very small effect. Out of over 40 electrophysiological endophenotypes covered by our review, only resting heart, a measure that has received scant advocacy as an endophenotype, emerges as an electrophysiological variable with verified associations with molecular genetic variants. To move the field forward, investigations designed to discover novel variants associated with endophenotypes will need extremely large samples best obtained by forming consortia and sharing data obtained from genome wide arrays. In addition, endophenotype research can benefit from successful molecular genetic studies of psychopathology by examining the degree to which these verified psychopathology-relevant variants are also associated with an endophenotype, and by using knowledge about the functional significance of these variants to generate new endophenotypes. Even without molecular genetic associations, endophenotypes still have value in studying the development of disorders in unaffected individuals at high genetic risk, constructing animal models, and gaining insight into neural mechanisms that are relevant to clinical disorder.
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What can time-frequency and phase coherence measures tell us about the genetic basis of P3 amplitude? Int J Psychophysiol 2016; 115:40-56. [PMID: 27871913 DOI: 10.1016/j.ijpsycho.2016.11.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 10/26/2016] [Accepted: 11/08/2016] [Indexed: 11/21/2022]
Abstract
In a recent comprehensive investigation, we largely failed to identify significant genetic markers associated with P3 amplitude or to corroborate previous associations between P3 and specific single nucleotide polymorphisms (SNPs) or genes. In the present study we extended this line of investigation to examine time-frequency (TF) activity and intertrial phase coherence (ITPC) in the P3 time window, both of which are associated with P3 amplitude. Previous genome-wide research has reported associations between P3-related theta and delta activity and individual genetic variants. A large, population-based sample of 4211 subjects, comprising male and female adolescent twins and their parents, was genotyped for 527,828 single nucleotide polymorphisms (SNPs), from which over six million SNPs were accurately imputed. Heritability estimates were greater for TF energy than ITPC, whether based on biometric models or the combined influence of all measured SNPs (derived from genome-wide complex trait analysis). The magnitude of overlap in the specific SNPs associated with delta energy and ITPC and P3 amplitude was significant. A genome-wide analysis of all SNPs, accompanied by an analysis of approximately 17,600 genes, indicated a region of chromosome 2 around TEKT4 that was significantly associated with theta ITPC. Analysis of candidate SNPs and genes previously reported to be associated with P3 or related phenotypes yielded one association surviving correction for multiple tests: between theta energy and CRHR1. However, we did not obtain significant associations for SNPs implicated in previous genome-wide studies of TF measures. Identifying specific genetic variants associated with P3 amplitude remains a challenge.
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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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Pandey AK, Kamarajan C, Manz N, Chorlian DB, Stimus A, Porjesz B. Delta, theta, and alpha event-related oscillations in alcoholics during Go/NoGo task: Neurocognitive deficits in execution, inhibition, and attention processing. Prog Neuropsychopharmacol Biol Psychiatry 2016; 65:158-71. [PMID: 26456730 PMCID: PMC4679474 DOI: 10.1016/j.pnpbp.2015.10.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 09/25/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
Higher impulsivity observed in alcoholics is thought to be due to neurocognitive functional deficits involving impaired inhibition in several brain regions and/or neuronal circuits. Event-related oscillations (EROs) offer time-frequency measure of brain rhythms during perceptual and cognitive processing, which provide a detailed view of neuroelectric oscillatory responses to external/internal events. The present study examines evoked power (temporally locked to events) of oscillatory brain signals in alcoholics during an equal probability Go/NoGo task, assessing their functional relevance in execution and inhibition of a motor response. The current study hypothesized that increases in the power of slow frequency bands and their topographical distribution is associated with tasks that have increased cognitive demands, such as the execution and inhibition of a motor response. Therefore, it is hypothesized that alcoholics would show lower spectral power in their topographical densities compared to controls. The sample consisted of 20 right-handed abstinent alcoholic males and 20 age and gender-matched healthy controls. Evoked delta (1.0-3.5Hz; 200-600ms), theta (4.0-7.5Hz; 200-400ms), slow alpha (8.0-9.5Hz; 200-300ms), and fast alpha (10.0-12.5Hz; 100-200ms) ERO power were compared across group and task conditions. Compared to controls, alcoholics had higher impulsiveness scores on the Barrett Impulsiveness Scale (BIS-11) and made more errors on Go trials. Alcoholics showed significantly lower evoked delta, theta, and slow alpha power compared to controls for both Go and NoGo task conditions, and lower evoked fast alpha power compared to controls for only the NoGo condition. The results confirm previous findings and are suggestive of neurocognitive deficits while executing and suppressing a motor response. Based on findings in the alpha frequency ranges, it is further suggested that the inhibitory processing impairments in alcoholics may arise from inadequate early attentional processing with respect to the stimulus related aspects/semantic memory processes, which may be reflected in lower posterio-temporal evoked fast alpha power. It can thus be concluded that alcoholics show neurocognitive deficits in both execution and suppression of a motor response and inadequate early attentional processing with respect to the semantic memory/stimulus related aspects while suppressing a motor response.
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Mayfield J, Arends MA, Harris RA, Blednov YA. Genes and Alcohol Consumption: Studies with Mutant Mice. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 126:293-355. [PMID: 27055617 PMCID: PMC5302130 DOI: 10.1016/bs.irn.2016.02.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this chapter, we review the effects of global null mutant and overexpressing transgenic mouse lines on voluntary self-administration of alcohol. We examine approximately 200 publications pertaining to the effects of 155 mouse genes on alcohol consumption in different drinking models. The targeted genes vary in function and include neurotransmitter, ion channel, neuroimmune, and neuropeptide signaling systems. The alcohol self-administration models include operant conditioning, two- and four-bottle choice continuous and intermittent access, drinking in the dark limited access, chronic intermittent ethanol, and scheduled high alcohol consumption tests. Comparisons of different drinking models using the same mutant mice are potentially the most informative, and we will highlight those examples. More mutants have been tested for continuous two-bottle choice consumption than any other test; of the 137 mouse genes examined using this model, 97 (72%) altered drinking in at least one sex. Overall, the effects of genetic manipulations on alcohol drinking often depend on the sex of the mice, alcohol concentration and time of access, genetic background, as well as the drinking test.
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Affiliation(s)
- J Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States
| | - M A Arends
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, United States
| | - R A Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States.
| | - Y A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States
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Kamarajan C, Pandey AK, Chorlian DB, Manz N, Stimus AT, Bauer LO, Hesselbrock VM, Schuckit MA, Kuperman S, Kramer J, Porjesz B. Reward processing deficits and impulsivity in high-risk offspring of alcoholics: A study of event-related potentials during a monetary gambling task. Int J Psychophysiol 2015; 98:182-200. [PMID: 26388585 PMCID: PMC4898464 DOI: 10.1016/j.ijpsycho.2015.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 09/08/2015] [Accepted: 09/11/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND Individuals at high risk to develop alcoholism often manifest neurocognitive deficits as well as increased impulsivity. The goal of the present study is to elucidate reward processing deficits, externalizing disorders, and impulsivity as elicited by electrophysiological, clinical and behavioral measures in subjects at high risk for alcoholism from families densely affected by alcoholism in the context of brain maturation across age groups and gender. METHODS Event-related potentials (ERPs) and current source density (CSD) during a monetary gambling task (MGT) were measured in 12-25 year old offspring (N=1864) of families in the Collaborative Study on the Genetics of Alcoholism (COGA) Prospective study; the high risk (HR, N=1569) subjects were from families densely affected with alcoholism and the low risk (LR, N=295) subjects were from community families. Externalizing disorders and impulsivity scores were also compared between LR and HR groups. RESULTS HR offspring from older (16-25 years) male and younger (12-15 years) female subgroups showed lower P3 amplitude than LR subjects. The amplitude decrement was most prominent in HR males during the loss condition. Overall, P3 amplitude increase at anterior sites and decrease at posterior areas were seen in older compared to younger subjects, suggesting frontalization during brain maturation. The HR subgroups also exhibited hypofrontality manifested as weaker CSD activity during both loss and gain conditions at frontal regions. Further, the HR subjects had higher impulsivity scores and increased prevalence of externalizing disorders. P3 amplitudes during the gain condition were negatively correlated with impulsivity scores. CONCLUSIONS Older male and younger female HR offspring, compared to their LR counterparts, manifested reward processing deficits as indexed by lower P3 amplitude and weaker CSD activity, along with higher prevalence of externalizing disorders and higher impulsivity scores. SIGNIFICANCE Reward related P3 is a valuable measure reflecting neurocognitive dysfunction in subjects at risk for alcoholism, as well as to characterize reward processing and brain maturation across gender and age group.
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Affiliation(s)
| | | | | | - Niklas Manz
- SUNY Downstate Medical Center, Brooklyn, NY, USA
| | | | - Lance O Bauer
- University of Connecticut Health Center, Farmington, CT, USA
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Malone SM, Vaidyanathan U, Basu S, Miller MB, McGue M, Iacono WG. Heritability and molecular-genetic basis of the P3 event-related brain potential: a genome-wide association study. Psychophysiology 2015; 51:1246-58. [PMID: 25387705 DOI: 10.1111/psyp.12345] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
P3 amplitude is a candidate endophenotype for disinhibitory psychopathology, psychosis, and other disorders. The present study is a comprehensive analysis of the behavioral- and molecular-genetic basis of P3 amplitude and a P3 genetic factor score in a large community sample (N = 4,211) of adolescent twins and their parents, genotyped for 527,829 single nucleotide polymorphisms (SNPs). Biometric models indicated that as much as 65% of the variance in each measure was due to additive genes. All SNPs in aggregate accounted for approximately 40% to 50% of the heritable variance. However, analyses of individual SNPs did not yield any significant associations. Analyses of individual genes did not confirm previous associations between P3 amplitude and candidate genes but did yield a novel association with myelin expression factor 2 (MYEF2). Main effects of individual variants may be too small to be detected by GWAS without larger samples.
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Affiliation(s)
- Stephen M Malone
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota, USA
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Chorlian DB, Rangaswamy M, Manz N, Kamarajan C, Pandey AK, Edenberg H, Kuperman S, Porjesz B. Gender modulates the development of theta event related oscillations in adolescents and young adults. Behav Brain Res 2015; 292:342-52. [PMID: 26102560 PMCID: PMC4705839 DOI: 10.1016/j.bbr.2015.06.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 06/09/2015] [Accepted: 06/11/2015] [Indexed: 12/16/2022]
Abstract
The developmental trajectories of theta band (4-7 Hz) event-related oscillations (EROs), a key neurophysiological constituent of the P3 response, were assessed in 2170 adolescents and young adults ages 12 to 25. The theta EROs occurring in the P3 response, important indicators of neurocognitive function, were elicited during the evaluation of task-relevant target stimuli in visual and auditory oddball tasks. These tasks call upon attentional and working memory resources. Large differences in developmental rates between males and females were found; scalp location and task modality (visual or auditory) differences within males and females were small compared to gender differences. Trajectories of interregional and intermodal correlations between ERO power values exhibited increases with age in both genders, but showed a divergence in development between auditory and visual systems during ages 16 to 21. These results are consistent with previous electrophysiological and imaging studies and provide additional temporal detail about the development of neurophysiological indices of cognitive activity. Since measures of the P3 response has been found to be a useful endophenotypes for the study of a number of clinical and behavioral disorders, studies of its development in adolescents and young adults may illuminate neurophysiological factors contributing to the onset of these conditions.
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Affiliation(s)
- David B Chorlian
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | | | - Niklas Manz
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Chella Kamarajan
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Ashwini K Pandey
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Howard Edenberg
- Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Bernice Porjesz
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA
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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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Wetherill L, Agrawal A, Kapoor M, Bertelsen S, Bierut LJ, Brooks A, Dick D, Hesselbrock M, Hesselbrock V, Koller DL, Le N, Nurnberger JI, Salvatore JE, Schuckit M, Tischfield JA, Wang JC, Xuei X, Edenberg HJ, Porjesz B, Bucholz K, Goate AM, Foroud T. Association of substance dependence phenotypes in the COGA sample. Addict Biol 2015; 20:617-27. [PMID: 24832863 PMCID: PMC4233207 DOI: 10.1111/adb.12153] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Alcohol and drug use disorders are individually heritable (50%). Twin studies indicate that alcohol and substance use disorders share common genetic influences, and therefore may represent a more heritable form of addiction and thus be more powerful for genetic studies. This study utilized data from 2322 subjects from 118 European-American families in the Collaborative Study on the Genetics of Alcoholism sample to conduct genome-wide association analysis of a binary and a continuous index of general substance dependence liability. The binary phenotype (ANYDEP) was based on meeting lifetime criteria for any DSM-IV dependence on alcohol, cannabis, cocaine or opioids. The quantitative trait (QUANTDEP) was constructed from factor analysis based on endorsement across the seven DSM-IV criteria for each of the four substances. Heritability was estimated to be 54% for ANYDEP and 86% for QUANTDEP. One single-nucleotide polymorphism (SNP), rs2952621 in the uncharacterized gene LOC151121 on chromosome 2, was associated with ANYDEP (P = 1.8 × 10(-8) ), with support from surrounding imputed SNPs and replication in an independent sample [Study of Addiction: Genetics and Environment (SAGE); P = 0.02]. One SNP, rs2567261 in ARHGAP28 (Rho GTPase-activating protein 28), was associated with QUANTDEP (P = 3.8 × 10(-8) ), and supported by imputed SNPs in the region, but did not replicate in an independent sample (SAGE; P = 0.29). The results of this study provide evidence that there are common variants that contribute to the risk for a general liability to substance dependence.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Nhung Le
- Washington University School of Medicine
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Manzardo AM, McGuire A, Butler MG. Clinically relevant genetic biomarkers from the brain in alcoholism with representation on high resolution chromosome ideograms. Gene 2015; 560:184-94. [PMID: 25655461 DOI: 10.1016/j.gene.2015.01.064] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/27/2015] [Accepted: 01/30/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Alcoholism arises from combined effects of multiple biological factors including genetic and non-genetic causes with gene/environmental interaction. Intensive research and advanced genetic technology has generated a long list of genes and biomarkers involved in alcoholism neuropathology. These markers reflect complex overlapping and competing effects of possibly hundreds of genes which impact brain structure, function, biochemical alcohol processing, sensitivity and risk for dependence. METHOD We compiled a tabular list of clinically relevant genetic biomarkers for alcoholism targeting expression disturbances in the human brain through an extensive search of keywords related to alcoholism, alcohol abuse, and genetics from peer reviewed medical research articles and related nationally sponsored websites. Gene symbols were then placed on high resolution human chromosome ideograms with gene descriptions in tabular form. RESULTS We identified 337 clinically relevant genetic biomarkers and candidate genes for alcoholism and alcohol-responsiveness from human brain research. Genetic biomarkers included neurotransmitter pathways associated with brain reward processes for dopaminergic (e.g., DRD2, MAOA, and COMT), serotoninergic (e.g., HTR3A, HTR1B, HTR3B, and SLC6A4), GABAergic (e.g., GABRA1, GABRA2, and GABRG1), glutaminergic (GAD1, GRIK3, and GRIN2C) and opioid (e.g., OPRM1, OPRD1, and OPRK1) pathways which presumably impact reinforcing properties of alcohol. Gene level disturbances in cellular and molecular networks impacted by alcohol and alcoholism pathology include transketolase (TKT), transferrin (TF), and myelin (e.g., MBP, MOBP, and MOG). CONCLUSIONS High resolution chromosome ideograms provide investigators, physicians, geneticists and counselors a convenient visual image of the distribution of alcoholism genetic biomarkers from brain research with alphabetical listing of genes in tabular form allowing comparison between alcoholism-related phenotypes, and clinically-relevant alcoholism gene(s) at the chromosome band level to guide research, diagnosis, and treatment. Chromosome ideograms may facilitate gene-based personalized counseling of alcohol dependent individuals and their families.
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Affiliation(s)
- Ann M Manzardo
- Department of Psychiatry & Behavioral Sciences, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Austen McGuire
- Department of Psychiatry & Behavioral Sciences, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Merlin G Butler
- Department of Psychiatry & Behavioral Sciences, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Pediatrics, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Salvatore JE, Gottesman II, Dick DM. Endophenotypes for Alcohol Use Disorder: An Update on the Field. CURRENT ADDICTION REPORTS 2015; 2:76-90. [PMID: 26236574 DOI: 10.1007/s40429-015-0046-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The endophenotype concept was first proposed as a strategy to use (purportedly) genetically simpler phenotypes in gene identification studies for psychiatric disorders, and is distinct from the closely related concept of intermediate phenotypes. In the area of alcohol use disorder (AUD) research, two candidate endophenotypes have produced replicable genetic associations: level of response to alcohol and neurophysiology markers (e.g., event-related oscillations and event-related potentials). Additional candidate endophenotypes from the cognitive, sensory, and neuroimaging literatures show promise, although more evidence is needed to fully evaluate their potential utility. Translational approaches to AUD endophenotypes have helped characterize the underlying neurobiology and genetics of AUD endophenotypes and identified relevant pharmacological interventions. Future research that capitalizes on the polygenic nature of endophenotypes and emphasizes endophenotypes that may change across development will enhance the usefulness of this concept to understand the genetically-influenced pathways toward AUD.
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Affiliation(s)
- Jessica E Salvatore
- Department of Psychiatry, Virginia Commonwealth University, PO Box 980126, Richmond, VA 23298-0126
| | - Irving I Gottesman
- Department of Psychology, University of Minnesota, N231 Elliott Hall, 75 East River Road, Minneapolis, MN 55455
| | - Danielle M Dick
- Department of Psychiatry, Virginia Commonwealth University, PO Box 980126, Richmond, VA 23298-0126
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Aliev F, Wetherill L, Bierut L, Bucholz KK, Edenberg H, Foroud T, Dick DM. Genes associated with alcohol outcomes show enrichment of effects with broad externalizing and impulsivity phenotypes in an independent sample. J Stud Alcohol Drugs 2015; 76:38-46. [PMID: 25486392 PMCID: PMC4263779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 07/16/2014] [Indexed: 06/04/2023] Open
Abstract
OBJECTIVE The purpose of this study was to evaluate evidence for association with a panel of genes previously associated with alcohol-related traits in a new sample of adolescent and young adult individuals (N = 2,128; 51% female) collected as part of the Collaborative Study on the Genetics of Alcoholism (COGA). We tested for association with phenotypes related to externalizing behavior, including diagnostic symptom counts for disorders on the externalizing spectrum (alcohol dependence, conduct disorder, adult antisocial personality disorder, and illicit drug dependence), and related behavioral/personality traits (Achenbach Externalizing, NEO Extraversion, NEO Conscientiousness, Zuckerman's Sensation Seeking, and the Barratt Impulsivity Scale) based on the substantial literature suggesting that these behaviors may be alternate manifestations of a shared genetic liability. METHOD We tested for overall enrichment of the set of 215 genotyped single-nucleotide polymorphisms (SNPs) for each of the phenotypes. We conducted secondary analyses comparing results for sensation seeking with results for the other phenotypes. RESULTS For all phenotypes, there was significant enrichment of association results (p < .05) compared with chance expectations. The greatest number of significant results was observed with the phenotype Sensation Seeking. Secondary analyses indicated that the number of SNPs yielding p < .05 with Sensation Seeking was significantly greater than that observed for each of the other phenotypes. CONCLUSIONS We find evidence for enrichment of association results across a spectrum of externalizing phenotypes with a panel of candidate genes/SNPs selected based on previous suggestion of association with alcohol-related outcomes. In particular, we find significant enrichment of effects with sensation seeking, suggesting that this may be a particularly salient behavior associated with risk for alcohol-related problems.
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Affiliation(s)
- Fazil Aliev
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
- Department of Actuarial and Risk Management, Faculty of Business, Karabuk University, Karabuk, Turkey
| | - Leah Wetherill
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Laura Bierut
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Kathleen K Bucholz
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Howard Edenberg
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Tatiana Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Coga Investigators
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
- Department of Actuarial and Risk Management, Faculty of Business, Karabuk University, Karabuk, Turkey
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Psychology, Virginia Commonwealth University, Richmond, Virginia
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - Danielle M Dick
- Department of Psychiatry, Virginia Commonwealth University, Richmond, Virginia
- Department of Psychology, Virginia Commonwealth University, Richmond, Virginia
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
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Blednov YA, Benavidez JM, Black M, Ferguson LB, Schoenhard GL, Goate AM, Edenberg HJ, Wetherill L, Hesselbrock V, Foroud T, Harris RA. Peroxisome proliferator-activated receptors α and γ are linked with alcohol consumption in mice and withdrawal and dependence in humans. Alcohol Clin Exp Res 2015; 39:136-45. [PMID: 25516156 PMCID: PMC4308472 DOI: 10.1111/acer.12610] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/19/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND Peroxisome proliferator-activated receptor (PPAR) agonists reduce voluntary ethanol (EtOH) consumption in rat models and are promising therapeutics in the treatment for drug addictions. We studied the effects of different classes of PPAR agonists on chronic EtOH intake and preference in mice with a genetic predisposition for high alcohol consumption and then examined human genomewide association data for polymorphisms in PPAR genes in alcohol-dependent subjects. METHODS Two different behavioral tests were used to measure intake of 15% EtOH in C57BL/6J male mice: 24-hour 2-bottle choice and limited access (3-hour) 2-bottle choice, drinking in the dark. We measured the effects of pioglitazone (10 and 30 mg/kg), fenofibrate (50 and 150 mg/kg), GW0742 (10 mg/kg), tesaglitazar (1.5 mg/kg), and bezafibrate (25 and 75 mg/kg) on EtOH intake and preference. Fenofibric acid, the active metabolite of fenofibrate, was quantified in mouse plasma, liver, and brain by liquid chromatography tandem mass spectrometry. Data from a human genome-wide association study (GWAS) completed in the Collaborative Study on the Genetics of Alcoholism (COGA) were then used to analyze the association of single nucleotide polymorphisms (SNPs) in different PPAR genes (PPARA, PPARD, PPARG, and PPARGC1A) with 2 phenotypes: DSM-IV alcohol dependence (AD) and the DSM-IV criterion of withdrawal. RESULTS Activation of 2 isoforms of PPARs, α and γ, reduced EtOH intake and preference in the 2 different consumption tests in mice. However, a selective PPARδ agonist or a pan agonist for all 3 PPAR isoforms did not decrease EtOH consumption. Fenofibric acid, the active metabolite of the PPARα agonist fenofibrate, was detected in liver, plasma, and brain after 1 or 8 days of oral treatment. The GWAS from COGA supported an association of SNPs in PPARA and PPARG with alcohol withdrawal and PPARGC1A with AD but found no association for PPARD with either phenotype. CONCLUSIONS We provide convergent evidence using both mouse and human data for specific PPARs in alcohol action. Reduced EtOH intake in mice and the genetic association between AD or withdrawal in humans highlight the potential for repurposing FDA-approved PPARα or PPARγ agonists for the treatment of AD.
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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
| | - Jillian M. Benavidez
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
| | - Mendy Black
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
| | - Laura B. Ferguson
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
- Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | | | - Alison M. Goate
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110
| | | | - Leah Wetherill
- Indiana University School of Medicine, Indianapolis, IN 46202
| | | | - Tatiana Foroud
- Indiana University School of Medicine, Indianapolis, IN 46202
| | - R. Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
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Kamarajan C, Porjesz B. Advances in Electrophysiological Research. Alcohol Res 2015; 37:53-87. [PMID: 26259089 PMCID: PMC4476604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Electrophysiological measures of brain function are effective tools to understand neurocognitive phenomena and sensitive indicators of pathophysiological processes associated with various clinical conditions, including alcoholism. Individuals with alcohol use disorder (AUD) and their high-risk offspring have consistently shown dysfunction in several electrophysiological measures in resting state (i.e., electroencephalogram) and during cognitive tasks (i.e., event-related potentials and event-related oscillations). Researchers have recently developed sophisticated signal-processing techniques to characterize different aspects of brain dynamics, which can aid in identifying the neural mechanisms underlying alcoholism and other related complex disorders.These quantitative measures of brain function also have been successfully used as endophenotypes to identify and help understand genes associated with AUD and related disorders. Translational research also is examining how brain electrophysiological measures potentially can be applied to diagnosis, prevention, and treatment.
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Affiliation(s)
- Chella Kamarajan
- Henri Begleiter Neurodynamics Laboratory, SUNY Downstate Medical Center, Brooklyn, New York
| | - Bernice Porjesz
- Henri Begleiter Neurodynamics Laboratory, SUNY Downstate Medical Center, Brooklyn, New York
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McClintick JN, McBride WJ, Bell RL, Ding ZM, Liu Y, Xuei X, Edenberg HJ. Gene expression changes in serotonin, GABA-A receptors, neuropeptides and ion channels in the dorsal raphe nucleus of adolescent alcohol-preferring (P) rats following binge-like alcohol drinking. Pharmacol Biochem Behav 2014; 129:87-96. [PMID: 25542586 PMCID: PMC4302739 DOI: 10.1016/j.pbb.2014.12.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/13/2014] [Accepted: 12/17/2014] [Indexed: 12/31/2022]
Abstract
Alcohol binge-drinking during adolescence is a serious public health concern with long-term consequences. We used RNA sequencing to assess the effects of excessive adolescent ethanol binge-drinking on gene expression in the dorsal raphe nucleus (DRN) of alcohol preferring (P) rats. Repeated binges across adolescence (three 1h sessions across the dark-cycle per day, 5 days per week for 3 weeks starting at 28 days of age; ethanol intakes of 2.5-3 g/kg/session) significantly altered the expression of approximately one-third of the detected genes. Multiple neurotransmitter systems were altered, with the largest changes in the serotonin system (21 of 23 serotonin-related genes showed decreased expression) and GABA-A receptors (8 decreased and 2 increased). Multiple neuropeptide systems were also altered, with changes in the neuropeptide Y and corticotropin-releasing hormone systems similar to those associated with increased drinking and decreased resistance to stress. There was increased expression of 21 of 32 genes for potassium channels. Expression of downstream targets of CREB signaling was increased. There were also changes in expression of genes involved in inflammatory processes, axonal guidance, growth factors, transcription factors, and several intracellular signaling pathways. These widespread changes indicate that excessive binge drinking during adolescence alters the functioning of the DRN and likely its modulation of many regions of the central nervous system, including the mesocorticolimbic system.
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Affiliation(s)
- Jeanette N McClintick
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - William J McBride
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Richard L Bell
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Zheng-Ming Ding
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Yunlong Liu
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Xiaoling Xuei
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Howard J Edenberg
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, United States.
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Iacono WG, Vaidyanathan U, Vrieze SI, Malone SM. Knowns and unknowns for psychophysiological endophenotypes: integration and response to commentaries. Psychophysiology 2014; 51:1339-47. [PMID: 25387720 PMCID: PMC4231488 DOI: 10.1111/psyp.12358] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We review and summarize seven molecular genetic studies of 17 psychophysiological endophenotypes that comprise this special issue of Psychophysiology, address criticisms raised in accompanying Perspective and Commentary pieces, and offer suggestions for future research. Endophenotypes are polygenic, and possibly influenced by rare genetic variants. Because they are not simpler genetically than clinical phenotypes, they are unlikely to assist gene discovery for psychiatric disorder. Once genetic variants for clinical phenotypes are identified, associated endophenotypes are likely to provide valuable insights into the psychological and neural mechanisms important to disorder pathology. This special issue provides a foundation for informed future steps in endophenotype genetics, including the formation of large sample consortia capable of fleshing out the many genetic variants contributing to individual differences in psychophysiological measures.
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Affiliation(s)
- William G Iacono
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota, USA
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Kapoor M, Wang JC, Wetherill L, Le N, Bertelsen S, Hinrichs AL, Budde J, Agrawal A, Almasy L, Bucholz K, Dick DM, Harari O, Xiaoling X, Hesselbrock V, Kramer J, Nurnberger JI, Rice J, Schuckit M, Tischfield J, Porjesz B, Edenberg HJ, Bierut L, Foroud T, Goate A. Genome-wide survival analysis of age at onset of alcohol dependence in extended high-risk COGA families. Drug Alcohol Depend 2014; 142:56-62. [PMID: 24962325 PMCID: PMC4127128 DOI: 10.1016/j.drugalcdep.2014.05.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/24/2014] [Accepted: 05/29/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND The age at onset of alcohol dependence (AD) is a critical moderator of genetic associations for alcohol dependence. The present study evaluated whether single nucleotide polymorphisms (SNPs) can influence the age at onset of AD in large high-risk families from the Collaborative Study on the Genetics of Alcoholism (COGA). METHODS Genomewide SNP genotyping was performed in 1788 regular drinkers from 118 large European American families densely affected with alcoholism. We used a genome-wide Cox proportional hazards regression model to test for association between age at onset of AD and SNPs. RESULTS This family-based analysis identified an intergenic SNP, rs2168784 on chromosome 3 that showed strong evidence of association (P=5×10(-9)) with age at onset of AD among regular drinkers. Carriers of the minor allele of rs2168784 had 1.5 times the hazard of AD onset as compared with those homozygous for the major allele. By the age of 20 years, nearly 30% of subjects homozygous for the minor allele were alcohol dependent while only 19% of those homozygous for the major allele were. We also identified intronic SNPs in the ADP-ribosylation factor like 15 (ARL15) gene on chromosome 5 (P=1.11×10(-8)) and the UTP20 small subunit (UTP20) gene on chromosome 12 (P=4.32×10(-8)) that were associated with age at onset of AD. CONCLUSIONS This extended family based genome-wide cox-proportional hazards analysis identified several loci that might be associated with age at onset of AD.
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Affiliation(s)
- Manav Kapoor
- Washington University School of Medicine, United States
| | | | | | - Nhung Le
- Washington University School of Medicine, United States
| | | | | | - John Budde
- Washington University School of Medicine, United States
| | | | - Laura Almasy
- Southwest Foundation for Biomedical Research, United States
| | | | | | - Oscar Harari
- Washington University School of Medicine, United States
| | - Xuei Xiaoling
- Indiana University School of Medicine, United States
| | | | - John Kramer
- University of Iowa Carver College of Medicine, United States
| | | | - John Rice
- Washington University School of Medicine, United States
| | | | | | | | | | - Laura Bierut
- Washington University School of Medicine, United States
| | | | - Alison Goate
- Washington University School of Medicine, United States.
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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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Mistry R, Babu GR, Mahapatra T, McCarthy WJ. Cognitive mediators and disparities in the relation between teen depressiveness and smoking. Drug Alcohol Depend 2014; 140:56-62. [PMID: 24768409 DOI: 10.1016/j.drugalcdep.2014.03.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 02/04/2014] [Accepted: 03/18/2014] [Indexed: 01/15/2023]
Abstract
BACKGROUND Depressiveness and tobacco use in adolescents are linked, however, there is limited evidence about the cognitive mediators involved and how the role of mediators may differ by gender and racial/ethnic subgroups. METHODS We used a racially/ethnically diverse population-based cross-sectional sample of middle and high school students (n=24,350). Logistic regression models measured the associations of depressiveness with tobacco smoking status, and whether smoking-related knowledge and attitudes (KA) and smoking refusal self-efficacy (SE) attenuated the associations indicating preliminary evidence of mediation. RESULTS Depressiveness was associated with intention to smoke (OR=2.41; 95% CI=2.22, 2.61), experimental smoking (OR=1.93; 95% CI=1.72, 2.17) and established smoking (OR=1.85; 95% CI=1.57, 2.18). The percent attenuation of these associations due to the inclusion of smoking-related KA and smoking refusal SE was 58% for intention to smoke (p<0.001), 68% for experimental smoking (p<0.001) and 86% for established smoking (p<0.001). The association of depressiveness with established smoking did not remain statistically significant (OR=1.16; CI=0.97, 1.40) after including smoking-related KA and smoking refusal SE. Attenuation was more pronounced in males and white students. CONCLUSIONS The results suggest that smoking-related KA and smoking refusal SE attenuated the relation between depressiveness and smoking, indicating that they may serve as mediators of the link between depressiveness and smoking. Tobacco use prevention programs targeting teens with the aim of increasing anti-smoking KA and smoking refusal SE may benefit from addressing depressiveness, particularly by using gender and racially/ethnically tailored strategies. The cross-sectional nature of the data precludes causal inferences.
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Affiliation(s)
- Ritesh Mistry
- Center for Cancer Prevention and Control Research, University of California, Los Angeles, United States; Department of Health Behavior and Health Education, University of Michigan, United States.
| | - Giridhara R Babu
- Department of Epidemiology, University of California, Los Angeles, United States; Indian Institute of Public Health-Hyderabad (Bangalore Wing), Public Health Foundation of India, India
| | - Tanmay Mahapatra
- Department of Epidemiology, University of California, Los Angeles, United States
| | - William J McCarthy
- Center for Cancer Prevention and Control Research, University of California, Los Angeles, United States
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Genetic psychophysiology: advances, problems, and future directions. Int J Psychophysiol 2014; 93:173-97. [PMID: 24739435 DOI: 10.1016/j.ijpsycho.2014.04.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 02/10/2014] [Accepted: 04/07/2014] [Indexed: 12/20/2022]
Abstract
This paper presents an overview of historical advances and the current state of genetic psychophysiology, a rapidly developing interdisciplinary research linking genetics, brain, and human behavior, discusses methodological problems, and outlines future directions of research. The main goals of genetic psychophysiology are to elucidate the neural pathways and mechanisms mediating genetic influences on cognition and emotion, identify intermediate brain-based phenotypes for psychopathology, and provide a functional characterization of genes being discovered by large association studies of behavioral phenotypes. Since the initiation of this neurogenetic approach to human individual differences in the 1970s, numerous twin and family studies have provided strong evidence for heritability of diverse aspects of brain function including resting-state brain oscillations, functional connectivity, and event-related neural activity in a variety of cognitive and emotion processing tasks, as well as peripheral psychophysiological responses. These data indicate large differences in the presence and strength of genetic influences across measures and domains, permitting the selection of heritable characteristics for gene finding studies. More recently, candidate gene association studies began to implicate specific genetic variants in different aspects of neurocognition. However, great caution is needed in pursuing this line of research due to its demonstrated proneness to generate false-positive findings. Recent developments in methods for physiological signal analysis, hemodynamic imaging, and genomic technologies offer new exciting opportunities for the investigation of the interplay between genetic and environmental factors in the development of individual differences in behavior, both normal and abnormal.
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Wetherill L, Kapoor M, Agrawal A, Bucholz K, Koller D, Bertelsen SE, Le N, Wang JC, Almasy L, Hesselbrock V, Kramer J, Nurnberger JI, Schuckit M, Tischfield JA, Xuei X, Porjesz B, Edenberg HJ, Goate AM, Foroud T. Family-based association analysis of alcohol dependence criteria and severity. Alcohol Clin Exp Res 2014; 38:354-66. [PMID: 24015780 PMCID: PMC3946798 DOI: 10.1111/acer.12251] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 07/08/2013] [Indexed: 01/08/2023]
Abstract
BACKGROUND Despite the high heritability of alcohol dependence (AD), the genes found to be associated with it account for only a small proportion of its total variability. The goal of this study was to identify and analyze phenotypes based on homogeneous classes of individuals to increase the power to detect genetic risk factors contributing to the risk of AD. METHODS The 7 individual DSM-IV criteria for AD were analyzed using latent class analysis (LCA) to identify classes defined by the pattern of endorsement of the criteria. A genome-wide association study was performed in 118 extended European American families (n = 2,322 individuals) densely affected with AD to identify genes associated with AD, with each of the 7 DSM-IV criteria, and with the probability of belonging to 2 of 3 latent classes. RESULTS Heritability for DSM-IV AD was 61% and ranged from 17 to 60% for the other phenotypes. A single nucleotide polymorphism (SNP) in the olfactory receptor OR51L1 was significantly associated (7.3 × 10(-8) ) with the DSM-IV criterion of persistent desire to, or inability to, cut down on drinking. LCA revealed a 3-class model: the "low-risk" class (50%) rarely endorsed any criteria and none met criteria for AD; the "moderate-risk" class (33%) endorsed primarily 4 DSM-IV criteria and 48% met criteria for AD; and the "high-risk" class (17%) manifested high endorsement probabilities for most criteria and nearly all (99%) met criteria for AD. One SNP in a sodium leak channel NALCN demonstrated genome-wide significance with the high-risk class (p = 4.1 × 10(-8) ). Analyses in an independent sample did not replicate these associations. CONCLUSIONS We explored the genetic contribution to several phenotypes derived from the DSM-IV AD criteria. The strongest evidence of association was with SNPs in NALCN and OR51L1.
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Affiliation(s)
| | | | | | | | | | | | - Nhung Le
- Washington University School of Medicine
| | | | | | | | - John Kramer
- University of Iowa Carver College of Medicine
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Rangaswamy M, Porjesz B. Understanding alcohol use disorders with neuroelectrophysiology. HANDBOOK OF CLINICAL NEUROLOGY 2014; 125:383-414. [PMID: 25307587 DOI: 10.1016/b978-0-444-62619-6.00023-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Neurocognitive deficits associated with impairments in various brain regions and neural circuitries, particularly involving frontal lobes, have been associated with chronic alcoholism, as well as with a predisposition to develop alcohol use and related disorders (AUDs). AUD is a multifactorial disorder caused by complex interactions between behavioral, genetic, and environmental liabilities. Neuroelectrophysiologic techniques are instrumental in understanding brain and behavior relationships and have also proved very useful in evaluating the genetic diathesis of alcoholism. This chapter describes findings from neuroelectrophysiologic measures (electroencephalogram, event-related potentials, and event-related oscillations) related to acute and chronic effects of alcohol on the brain and those that reflect underlying deficits related to a predisposition to develop AUDs and related disorders. The utility of these measures as effective endophenotypes to identify and understand genes associated with brain electrophysiology, cognitive networks, and AUDs has also been discussed.
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Affiliation(s)
- Madhavi Rangaswamy
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Bernice Porjesz
- Henri Begleiter Neurodynamics Laboratory, Department of Psychiatry and Behavioral Sciences, SUNY Downstate Medical Center, Brooklyn, NY, USA.
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Perspectives on the neuroscience of alcohol from the National Institute on Alcohol Abuse and Alcoholism. HANDBOOK OF CLINICAL NEUROLOGY 2014; 125:15-29. [PMID: 25307566 DOI: 10.1016/b978-0-444-62619-6.00002-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mounting evidence over the last 40 years clearly indicates that alcoholism (alcohol dependence) is a disorder of the brain. The National Institute on Alcohol Abuse and Alcoholism (NIAAA) has taken significant steps to advance research into the neuroscience of alcohol. The Division of Neuroscience and Behavior (DNB) was formed within NIAAA in 2002 to oversee, fund, and direct all research areas that examine the effects of alcohol on the brain, the genetic underpinnings of alcohol dependence, the neuroadaptations resulting from excessive alcohol consumption, advanced behavioral models of the various stages of the addiction cycle, and preclinical medications development. This research portfolio has produced important discoveries in the etiology, treatment, and prevention of alcohol abuse and dependence. Several of these salient discoveries are highlighted and future areas of neuroscience research on alcohol are presented.
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Kaufmann K, Romaine I, Days E, Pascual C, Malik A, Yang L, Zou B, Du Y, Sliwoski G, Morrison RD, Denton J, Niswender CM, Daniels JS, Sulikowski GA, Xie X(S, Lindsley CW, Weaver CD. ML297 (VU0456810), the first potent and selective activator of the GIRK potassium channel, displays antiepileptic properties in mice. ACS Chem Neurosci 2013; 4:1278-86. [PMID: 23730969 DOI: 10.1021/cn400062a] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The G-protein activated, inward-rectifying potassium (K(+)) channels, "GIRKs", are a family of ion channels (Kir3.1-Kir3.4) that has been the focus of intense research interest for nearly two decades. GIRKs are comprised of various homo- and heterotetrameric combinations of four different subunits. These subunits are expressed in different combinations in a variety of regions throughout the central nervous system and in the periphery. The body of GIRK research implicates GIRK in processes as diverse as controlling heart rhythm, to effects on reward/addiction, to modulation of response to analgesics. Despite years of GIRK research, very few tools exist to selectively modulate GIRK channels' activity and until now no tools existed that potently and selectively activated GIRKs. Here we report the development and characterization of the first truly potent, effective, and selective GIRK activator, ML297 (VU0456810). We further demonstrate that ML297 is active in two in vivo models of epilepsy, a disease where up to 40% of patients remain with symptoms refractory to present treatments. The development of ML297 represents a truly significant advancement in our ability to selectively probe GIRK's role in physiology as well as providing the first tool for beginning to understand GIRK's potential as a target for a diversity of therapeutic indications.
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Affiliation(s)
| | | | | | - Conrado Pascual
- AfaSci Research Laboratory, Redwood City, California
94063, United States
| | - Adam Malik
- AfaSci Research Laboratory, Redwood City, California
94063, United States
| | - Liya Yang
- AfaSci Research Laboratory, Redwood City, California
94063, United States
| | - Bende Zou
- AfaSci Research Laboratory, Redwood City, California
94063, United States
| | | | | | | | | | | | | | | | - Xinmin (Simon) Xie
- AfaSci Research Laboratory, Redwood City, California
94063, United States
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Abstract
Alcohol is widely consumed; however, excessive use creates serious physical, psychological and social problems and contributes to the pathogenesis of many diseases. Alcohol use disorders (that is, alcohol dependence and alcohol abuse) are maladaptive patterns of excessive drinking that lead to serious problems. Abundant evidence indicates that alcohol dependence (alcoholism) is a complex genetic disease, with variations in a large number of genes affecting a person's risk of alcoholism. Some of these genes have been identified, including two genes involved in the metabolism of alcohol (ADH1B and ALDH2) that have the strongest known affects on the risk of alcoholism. Studies continue to reveal other genes in which variants affect the risk of alcoholism or related traits, including GABRA2, CHRM2, KCNJ6 and AUTS2. As more variants are analysed and studies are combined for meta-analysis to achieve increased sample sizes, an improved picture of the many genes and pathways that affect the risk of alcoholism will be possible.
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Affiliation(s)
- Howard J Edenberg
- Department of Biochemistry, Indiana University School of Medicine, 635 Barnhill Drive, MS4063, Indianapolis, IN 46202-5122, USA.
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Palmer RHC, McGeary JE, Francazio S, Raphael BJ, Lander AD, Heath AC, Knopik VS. The genetics of alcohol dependence: advancing towards systems-based approaches. Drug Alcohol Depend 2012; 125:179-91. [PMID: 22854292 PMCID: PMC3470479 DOI: 10.1016/j.drugalcdep.2012.07.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 07/09/2012] [Accepted: 07/10/2012] [Indexed: 01/02/2023]
Abstract
BACKGROUND Personalized treatment for psychopathologies, in particular alcoholism, is highly dependent upon our ability to identify patterns of genetic and environmental effects that influence a person's risk. Unfortunately, array-based whole genome investigations into heritable factors that explain why one person becomes dependent upon alcohol and another does not, have indicated that alcohol's genetic architecture is highly complex. That said, uncovering and interpreting the missing heritability in alcohol genetics research has become all the more important, especially since the problem may extend to our inability to model the cumulative and combinatorial relationships between common and rare genetic variants. As numerous studies begin to illustrate the dependency of alcohol pharmacotherapies on an individual's genotype, the field is further challenged to identify new ways to transcend agnostic genomewide association approaches. We discuss insights from genetic studies of alcohol related diseases, as well as issues surrounding alcohol's genetic complexity and etiological heterogeneity. Finally, we describe the need for innovative systems-based approaches (systems genetics) that can provide additional statistical power that can enhance future gene-finding strategies and help to identify heretofore-unrealized mechanisms that may provide new targets for prevention/treatments efforts. Emerging evidence from early studies suggest that systems genetics has the potential to organize our neurological, pharmacological, and genetic understanding of alcohol dependence into a biologically plausible framework that represents how perturbations across evolutionarily robust biological systems determine susceptibility to alcohol dependence.
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Affiliation(s)
- R H C Palmer
- Division of Behavioral Genetics, Department of Psychiatry at Rhode Island Hospital, USA.
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