1
|
Yang J, Wang H, Chen H, Hou H, Hu Q. The association of genetic polymorphisms within the dopaminergic system with nicotine dependence: A narrative review. Heliyon 2024; 10:e33158. [PMID: 39021905 PMCID: PMC11253068 DOI: 10.1016/j.heliyon.2024.e33158] [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: 07/01/2023] [Revised: 06/08/2024] [Accepted: 06/14/2024] [Indexed: 07/20/2024] Open
Abstract
Nicotine, the main compound in cigarettes, leads to smoking addiction. Nicotine acts on the limbic dopamine reward loop in the midbrain by binding to nicotinic acetylcholine receptors, promoting the release of dopamine, and resulting in a rewarding effect or satisfaction. This satisfaction is essential for continued and compulsive tobacco use, and therefore dopamine plays a crucial role in nicotine dependence. Numerous studies have identified genetic polymorphisms of dopaminergic pathways which may influence susceptibility to nicotine addiction. Dopamine levels are greatly influenced by synthesis, storage, release, degradation, and reuptake-related genes, including genes encoding tyrosine hydroxylase, dopamine decarboxylase, dopamine transporter, dopamine receptor, dopamine 3-hydroxylase, catechol-O-methyltransferase, and monoamine oxidase. In this paper, we review research progress on the effects of polymorphisms in the above genes on downstream smoking behavior and nicotine dependence, to offer a theoretical basis for the elucidation of the genetic mechanism underlying nicotine dependence and future personalized treatment for smoking cessation.
Collapse
Affiliation(s)
- Jingjing Yang
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, 450001, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, 450001, China
- Beijing Life Science Academy, Beijing, 102209, China
- Key Laboratory of Tobacco Biological Effects and Biosynthesis, Beijing, 102209, China
| | - Hongjuan Wang
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, 450001, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, 450001, China
- Beijing Life Science Academy, Beijing, 102209, China
- Key Laboratory of Tobacco Biological Effects and Biosynthesis, Beijing, 102209, China
| | - Huan Chen
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, 450001, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, 450001, China
- Beijing Life Science Academy, Beijing, 102209, China
- Key Laboratory of Tobacco Biological Effects and Biosynthesis, Beijing, 102209, China
| | - Hongwei Hou
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, 450001, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, 450001, China
- Beijing Life Science Academy, Beijing, 102209, China
- Key Laboratory of Tobacco Biological Effects and Biosynthesis, Beijing, 102209, China
| | - Qingyuan Hu
- China National Tobacco Quality Supervision & Test Center, Zhengzhou, 450001, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, 450001, China
- Beijing Life Science Academy, Beijing, 102209, China
- Key Laboratory of Tobacco Biological Effects and Biosynthesis, Beijing, 102209, China
| |
Collapse
|
2
|
Prom-Wormley EC, Wells JL, Landes L, Edmondson AN, Sankoh M, Jamieson B, Delk KJ, Surya S, Bhati S, Clifford J. A scoping review of smoking cessation pharmacogenetic studies to advance future research across racial, ethnic, and ancestral populations. Front Genet 2023; 14:1103966. [PMID: 37359362 PMCID: PMC10285878 DOI: 10.3389/fgene.2023.1103966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 04/25/2023] [Indexed: 06/28/2023] Open
Abstract
Abstinence rates among smokers attempting to quit remain low despite the wide availability and accessibility of pharmacological smoking cessation treatments. In addition, the prevalence of cessation attempts and abstinence differs by individual-level social factors such as race and ethnicity. Clinical treatment of nicotine dependence also continues to be challenged by individual-level variability in effectiveness to promote abstinence. The use of tailored smoking cessation strategies that incorporate information on individual-level social and genetic factors hold promise, although additional pharmacogenomic knowledge is still needed. In particular, genetic variants associated with pharmacological responses to smoking cessation treatment have generally been conducted in populations with participants that self-identify as White race or who are determined to be of European genetic ancestry. These results may not adequately capture the variability across all smokers as a result of understudied differences in allele frequencies across genetic ancestry populations. This suggests that much of the current pharmacogenetic study results for smoking cessation may not apply to all populations. Therefore, clinical application of pharmacogenetic results may exacerbate health inequities by racial and ethnic groups. This scoping review examines the extent to which racial, ethnic, and ancestral groups that experience differences in smoking rates and smoking cessation are represented in the existing body of published pharmacogenetic studies of smoking cessation. We will summarize results by race, ethnicity, and ancestry across pharmacological treatments and study designs. We will also explore current opportunities and challenges in conducting pharmacogenomic research on smoking cessation that encourages greater participant diversity, including practical barriers to clinical utilization of pharmacological smoking cessation treatment and clinical implementation of pharmacogenetic knowledge.
Collapse
Affiliation(s)
- Elizabeth C. Prom-Wormley
- Division of Epidemiology, Department of Family Medicine and Population Health, Virginia Commonwealth University, Richmond, VA, United States
| | - Jonathan L. Wells
- Division of Epidemiology, Department of Family Medicine and Population Health, Virginia Commonwealth University, Richmond, VA, United States
| | - Lori Landes
- Department of Family Medicine and Population Health, Virginia Commonwealth University, Richmond, VA, United States
| | - Amy N. Edmondson
- Division of Epidemiology, Department of Family Medicine and Population Health, Virginia Commonwealth University, Richmond, VA, United States
| | - Mariam Sankoh
- Department of Integrative Life Sciences, Virginia Commonwealth University, Richmond, VA, United States
| | - Brendan Jamieson
- Division of Epidemiology, Department of Family Medicine and Population Health, Virginia Commonwealth University, Richmond, VA, United States
| | - Kayla J. Delk
- Division of Epidemiology, Department of Family Medicine and Population Health, Virginia Commonwealth University, Richmond, VA, United States
| | - Sanya Surya
- Division of Epidemiology, Department of Family Medicine and Population Health, Virginia Commonwealth University, Richmond, VA, United States
| | - Shambhavi Bhati
- Division of Epidemiology, Department of Family Medicine and Population Health, Virginia Commonwealth University, Richmond, VA, United States
| | - James Clifford
- Department of Public Health, Brody School of Medicine, East Carolina University, Greenville, United States
| |
Collapse
|
3
|
Perez-Paramo YX, Lazarus P. Pharmacogenetics factors influencing smoking cessation success; the importance of nicotine metabolism. Expert Opin Drug Metab Toxicol 2021; 17:333-349. [PMID: 33322962 PMCID: PMC8049967 DOI: 10.1080/17425255.2021.1863948] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/10/2020] [Indexed: 01/12/2023]
Abstract
Introduction: Smoking remains a worldwide epidemic, and despite an increase in public acceptance of the harms of tobacco use, it remains the leading cause of preventable death. It is estimated that up to 70% of all smokers express a desire to quit, but only 3-5% of them are successful.Areas covered: The goal of this review was to evaluate the current status of smoking cessation treatments and the feasibility of implementing personalized-medicine approaches to these pharmacotherapies. We evaluated the genetics associated with higher levels of nicotine addiction and follow with an analysis of the genetic variants that affect the nicotine metabolic ratio (NMR) and the FDA approved treatments for smoking cessation. We also highlighted the gaps in the process of translating current laboratory understanding into clinical practice, and the benefits of personalized treatment approaches for a successful smoking cessation strategy.Expert opinion: Evidence supports the use of tailored therapies to ensure that the most efficient treatments are utilized in an individual's smoking cessation efforts. An understanding of the genetic effects on the efficacy of individualized smoking cessation pharmacotherapies is key to smoking cessation, ideally utilizing a polygenetic risk score that considers all genetic variation.
Collapse
Affiliation(s)
- Yadira X. Perez-Paramo
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington, USA
| | - Philip Lazarus
- Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington, USA
| |
Collapse
|
4
|
Leukel C, Schümann D, Kalisch R, Sommer T, Bunzeck N. Dopamine Related Genes Differentially Affect Declarative Long-Term Memory in Healthy Humans. Front Behav Neurosci 2020; 14:539725. [PMID: 33328916 PMCID: PMC7673390 DOI: 10.3389/fnbeh.2020.539725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 09/04/2020] [Indexed: 11/22/2022] Open
Abstract
In humans, monetary reward can promote behavioral performance including response times, accuracy, and subsequent recognition memory. Recent studies have shown that the dopaminergic system plays an essential role here, but the link to interindividual differences remains unclear. To further investigate this issue, we focused on previously described polymorphisms of genes affecting dopaminergic neurotransmission: DAT1 40 base pair (bp), DAT1 30 bp, DRD4 48 bp, and cannabinoid receptor type 1 (CNR1). Specifically, 669 healthy humans participated in a delayed recognition memory paradigm on two consecutive days. On the first day, male vs. female faces served as cues predicting an immediate monetary reward upon correct button presses. Subsequently, participants performed a remember/know recognition memory task on the same day and 1 day later. As predicted, reward increased accuracy and accelerated response times, which were modulated by DAT 30 bp. However, reward did not promote subsequent recognition memory performance and there was no interaction with any genotype tested here. Importantly, there were differential effects of genotype on declarative long-term memory independent of reward: (a) DAT1 40 bp was linked to the quality of memory with a more pronounced difference between recollection and familiarity in the heterozygous and homozygous 10-R as compared to homozygous 9-R; (b) DAT1 30 bp was linked to memory decay, which was most pronounced in homozygous 4-R; (c) DRD4 48 bp was linked to overall recognition memory with higher performance in the short allele group; and (d) CNR1 was linked to overall memory with reduced performance in the homozygous short group. These findings give new insights into how polymorphisms, which are related to dopaminergic neuromodulation, differentially affect long-term recognition memory performance.
Collapse
Affiliation(s)
- Carla Leukel
- Department of Psychology, University of Lübeck, Lübeck, Germany
| | - Dirk Schümann
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Raffael Kalisch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Neuroimaging Center (NIC), Focus Program Translational Neuroscience, Johannes Gutenberg University Medical Center, Mainz, Germany.,Leibniz Institute for Resilience Research (LIR), Mainz, Germany
| | - Tobias Sommer
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nico Bunzeck
- Department of Psychology, University of Lübeck, Lübeck, Germany.,Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany
| |
Collapse
|
5
|
Shi Z, Wang AL, Aronowitz CA, Romer D, Langleben DD. Individual differences in the processing of smoking-cessation video messages: An imaging genetics study. Biol Psychol 2017; 128:125-131. [PMID: 28757070 PMCID: PMC5731475 DOI: 10.1016/j.biopsycho.2017.07.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 07/21/2017] [Accepted: 07/24/2017] [Indexed: 11/25/2022]
Abstract
Studies testing the benefits of enriching smoking-cessation video ads with attention-grabbing sensory features have yielded variable results. Dopamine transporter gene (DAT1) has been implicated in attention deficits. We hypothesized that DAT1 polymorphism is partially responsible for this variability. Using functional magnetic resonance imaging, we examined brain responses to videos high or low in attention-grabbing features, indexed by "message sensation value" (MSV), in 53 smokers genotyped for DAT1. Compared to other smokers, 10/10 homozygotes showed greater neural response to High- vs. Low-MSV smoking-cessation videos in two a priori regions of interest: the right temporoparietal junction and the right ventrolateral prefrontal cortex. These regions are known to underlie stimulus-driven attentional processing. Exploratory analysis showed that the right temporoparietal response positively predicted follow-up smoking behavior indexed by urine cotinine. Our findings suggest that responses to attention-grabbing features in smoking-cessation messages is affected by the DAT1 genotype.
Collapse
Affiliation(s)
- Zhenhao Shi
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States; Annenberg Public Policy Center, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - An-Li Wang
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Catherine A Aronowitz
- Annenberg Public Policy Center, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Daniel Romer
- Annenberg Public Policy Center, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Daniel D Langleben
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States; Annenberg Public Policy Center, University of Pennsylvania, Philadelphia, PA 19104, United States; Corporal Michael J. Crescenz Veterans Administration Medical Center, Philadelphia, PA 19104, United States.
| |
Collapse
|
6
|
Li S, Wang Q, Pan L, Li H, Yang X, Jiang F, Zhang N, Han M, Jia C. The association of dopamine pathway gene score, nicotine dependence and smoking cessation in a rural male population of Shandong, China. Am J Addict 2016; 25:493-8. [PMID: 27490263 DOI: 10.1111/ajad.12421] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/16/2016] [Accepted: 07/25/2016] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Smoking and smoking cessation are both psychological and physiological traits. We aimed to investigate the interaction between dopamine pathway gene scores and nicotine dependence on smoking cessation in a rural Chinese male population. METHODS Participants were recruited from 17 villages in Shandong, China. DNA was extracted from blood sample of 819 participants. 25 single nucleotide polymorphisms (SNPs) in 8 dopamine (DA) pathway genes were genotyped. Weighted gene score of each gene is used to analyze the whole gene effect. Logistic regression was used to calculate odds ratios (OR) and multivariate-adjusted OR of each gene score for smoking cessation. Multiplicative model interaction was assessed through a cross-product interaction term of gene score by nicotine dependence in a multivariate logistic regression model. RESULTS After adjusting for age, occupation, education, marital status, self-rating anxiety score, and disease status, we observed significant negative associations of catechol-O-methyltransferase (COMT), dopamine receptor D2 (DRD2) gene score and smoking cessation, as well as significant positive associations between ankyrin repeat and kinase domain containing 1 (ANKK1), dopamine transporter (SLC6A3), dopamine receptor D4 (DRD4) gene score and smoking cessation. A significant multiplicative model interaction between nicotine dependence and the SLC6A3 gene score on smoking cessation was also observed (p = .03). CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE There is a significant multiplicative model interaction of SLC6A3 gene score and nicotine dependence on smoking cessation. This finding could help to identify smokers who may be at high risk of relapse, and thus to develop more professional and personalized smoking cessation treatment. (Am J Addict 2016;25:493-498).
Collapse
Affiliation(s)
- Suyun Li
- Department of Epidemiology, Shandong University, Jinan, P. R. China
| | - Qiang Wang
- Department of Epidemiology, Shandong University, Jinan, P. R. China
| | - Lulu Pan
- Hebei Center for Disease Control and Prevention, Hebei, P. R. China
| | - Huijie Li
- Department of Epidemiology, Shandong University, Jinan, P. R. China
| | - Xiaorong Yang
- Department of Epidemiology, Shandong University, Jinan, P. R. China
| | - Fan Jiang
- Department of Epidemiology, Shandong University, Jinan, P. R. China
| | - Nan Zhang
- Department of Epidemiology, Shandong University, Jinan, P. R. China
| | - Mingkui Han
- Department of Epidemiology, Shandong University, Jinan, P. R. China
| | - Chongqi Jia
- Department of Epidemiology, Shandong University, Jinan, P. R. China
| |
Collapse
|
7
|
Choi HD, Shin WG. Meta-analysis update of association between dopamine transporter SLC6A3 gene polymorphism and smoking cessation. J Health Psychol 2016; 23:1250-1257. [PMID: 27287604 DOI: 10.1177/1359105316648479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The SLC6A3 gene is involved in the dopamine pathway, which influences smoking behavior. This study was conducted to present updated results of a meta-analysis to evaluate the association between SLC6A3 polymorphism and smoking cessation. In total, eight studies were assessed, and 9-repeat alleles and no 9-repeat alleles were compared by smoking cessation outcomes. No significant association between SLC6A3 genotype and smoking cessation was observed for the main analysis (odds ratio = 1.128; 95% confidence interval = 0.981-1.298). In conclusion, the genetic variations in SLC6A3 are not associated with smoking cessation, which is not consistent with the results of the previous meta-analysis.
Collapse
|
8
|
Kennedy JL, Xiong N, Yu J, Zai CC, Pouget JG, Li J, Liu K, Qing H, Wang T, Martin E, Levy DL, Lin Z. Increased Nigral SLC6A3 Activity in Schizophrenia Patients: Findings From the Toronto-McLean Cohorts. Schizophr Bull 2016; 42:772-81. [PMID: 26707863 PMCID: PMC4838105 DOI: 10.1093/schbul/sbv191] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
SLC6A3, which encodes the primary regulator of extracellular dopamine (DA) concentration, the DA transporter, has been implicated in schizophrenia (SCZ). However, the details of its genetic effect on risk remain largely unknown. The purpose of this candidate gene study was to identify a specificSLC6A3activity associated with SCZ by using functional genetic approaches. We first examined gene activity in DA neurons isolated from case-control postmortem nigral tissue and found that the averageSLC6A3mRNA level in controls was only 0.37-fold of that in cases (P= .0034). To understand this expression difference, we examined the association of 10 genetic markers, mostly located in the promoter region, with SCZ in 1717 subjects collected from Toronto and McLean cohorts, including 881 controls and 836 cases and identified the 5' promoter SNP rs1478435 as having a significant association signal (uncorrectedPvalue: .00462; adjustedPvalue: .0319) in unrelated Caucasians. Allele T was over-represented in controls (OR = .75); T-carrier controls had decreased mRNA levels in nigral DA neurons, contributing to the reduced activity in the controls. In vitro functional analysis confirmed that T carriers displayed attenuated enhancement of promoter activity. These findings collectively suggest that increased nigralSLC6A3activity may be a risk factor for SCZ, and may help to explain high rates of comorbidity with substance abuse.
Collapse
Affiliation(s)
- James L. Kennedy
- Neurogenetics Section, Neuroscience Research Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada;,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada;,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Nian Xiong
- Laboratory of Psychiatric Neurogenomics, McLean Hospital, Belmont, MA;,Department of Psychiatry, Harvard Medical School, Boston, MA;,Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinlong Yu
- Laboratory of Psychiatric Neurogenomics, McLean Hospital, Belmont, MA;,Department of Psychiatry, Harvard Medical School, Boston, MA
| | - Clement C. Zai
- Neurogenetics Section, Neuroscience Research Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada;,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada;,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Jennie G. Pouget
- Neurogenetics Section, Neuroscience Research Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada;,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada;,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Jie Li
- Laboratory of Psychiatric Neurogenomics, McLean Hospital, Belmont, MA;,Department of Psychiatry, Harvard Medical School, Boston, MA;,Institute of Psychiatry, Tianjin Mental Health Center, Tianjin, China
| | - Kefu Liu
- Laboratory of Psychiatric Neurogenomics, McLean Hospital, Belmont, MA;,Department of Psychiatry, Harvard Medical School, Boston, MA;,School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Hong Qing
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Tao Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Eden Martin
- Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL
| | - Deborah L. Levy
- Department of Psychiatry, Harvard Medical School, Boston, MA;,Psychology Research Laboratory, McLean Hospital, Belmont, MA,Joint last author
| | - Zhicheng Lin
- Laboratory of Psychiatric Neurogenomics, McLean Hospital, Belmont, MA; Department of Psychiatry, Harvard Medical School, Boston, MA;
| |
Collapse
|
9
|
Meta-analysis reveals significant association of 3'-UTR VNTR in SLC6A3 with smoking cessation in Caucasian populations. THE PHARMACOGENOMICS JOURNAL 2015; 16:10-7. [PMID: 26149737 PMCID: PMC4705003 DOI: 10.1038/tpj.2015.44] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 03/29/2015] [Accepted: 05/18/2015] [Indexed: 12/11/2022]
Abstract
Many studies have examined the association between SLC6A3 3′-UTR VNTR polymorphism and smoking cessation; however, the results are inconclusive, primarily because of the small to moderate-size samples. The primary goal of this study was to determine whether this polymorphism has any effect on smoking cessation by a meta-analysis of all reported studies. We adopted a 9-repeat dominant model that considers 9-repeat and non 9-repeat as two genotypes and compared their frequencies in former vs. current smokers. Eleven studies with 5,480 participants were included. Considering the presence of study heterogeneity and differences in the availability of information from each study, three separate meta-analyses were performed with the Comprehensive Meta-Analysis statistical software (v. 2.0). The first meta-analysis provided evidence of association between the 9-repeat genotype and smoking cessation under the fixed-effects model (pooled odds ratio [OR] 1.13; 95% confidence interval [CI] 1.01, 1.27; P = 0.037) but not in the random-effects model (pooled OR 1.11; 95% CI 0.96, 1.29; P = 0.159). Given the marginal evidence of heterogeneity among studies (P = 0.10; I2 = 35.9%), which likely was caused by inclusion of an Asian-population treatment study with an opposite effect of the polymorphism on smoking cessation, we excluded these data, revealing a significant association between the 9-repeat genotype and smoking cessation under both the fixed- and random-effects models (pooled OR 1.15; 95% CI 1.02, 1.29; P = 0.02 for both models). By analyzing adjusted and unadjusted results, we performed the third meta-analysis, which showed consistently that the 9-repeat genotype was significantly associated with smoking cessation under both the fixed- and random-effects models (pooled OR 1.17; 95% CI 1.04, 1.31; P = 0.009 for both models). We conclude that the 3′-UTR VNTR polymorphism is significantly associated with smoking cessation, and smokers with one or more 9-repeat alleles have a 17% higher probability of smoking cessation than smokers carrying no such allele.
Collapse
|
10
|
A review of pharmacogenetic studies of substance-related disorders. Drug Alcohol Depend 2015; 152:1-14. [PMID: 25819021 PMCID: PMC4458176 DOI: 10.1016/j.drugalcdep.2015.03.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/05/2015] [Accepted: 03/02/2015] [Indexed: 12/27/2022]
Abstract
BACKGROUND Substance-related disorders (SRDs) are a major cause of morbidity and mortality worldwide. Family, twin, and adoption studies have demonstrated the substantial heritability of SRDs. To determine the impact of genetic variation on risk for SRD and the response to treatment, researchers have conducted a number of secondary data analyses and quasi-experimental studies that target one or more candidate gene variants. METHODS This review examines studies in which candidate polymorphisms were examined as mediator variables to identify pharmacogenetic effects on subjective responses to drug administration or cues or outcomes of medication trials for SRDs. Efforts to use a meta-analytic approach to quantify these effects are premature because the number of available studies using similar methods and outcomes is limited, so the present review is qualitative. RESULTS Findings from these studies provide preliminary evidence of clinically relevant pharmacogenetic effects. However, independent replication of these findings has been sparse. CONCLUSIONS Although this growing body of literature has produced conflicting results, improved statistical controls may help to clarify the findings. Additionally, the use of empirically derived sub-phenotypes (i.e., which serve to differentiate distinct groups of affected individuals) may also help to identify genetic mediators of pharmacologic response in relation to SRDs. The identification of genetic mediators can inform clinical care both by identifying risk factors for SRDs and predicting adverse events and therapeutic outcomes associated with specific pharmacotherapies.
Collapse
|
11
|
Blum K, Thanos PK, Badgaiyan RD, Febo M, Oscar-Berman M, Fratantonio J, Demotrovics Z, Gold MS. Neurogenetics and gene therapy for reward deficiency syndrome: are we going to the Promised Land? Expert Opin Biol Ther 2015; 15:973-85. [PMID: 25974314 DOI: 10.1517/14712598.2015.1045871] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Addiction is a substantial health issue with limited treatment options approved by the FDA and as such currently available. The advent of neuroimaging techniques that link neurochemical and neurogenetic mechanisms to the reward circuitry brain function provides a framework for potential genomic-based therapies. AREAS COVERED Through candidate and genome-wide association studies approaches, many gene polymorphisms and clusters have been implicated in drug, food and behavioral dependence linked by the common rubric reward deficiency syndrome (RDS). The results of selective studies that include the role of epigenetics, noncoding micro RNAs in RDS behaviors especially drug abuse involving alcohol, opioids, cocaine, nicotine, pain and feeding are reviewed in this article. New targets for addiction treatment and relapse prevention, treatment alternatives such as gene therapy in animal models, and pharmacogenomics and nutrigenomics methods to manipulate transcription and gene expression are explored. EXPERT OPINION The recognition of the clinical benefit of early genetic testing to determine addiction risk stratification and dopaminergic agonistic, rather than antagonistic therapies are potentially the genomic-based wave of the future. In addition, further development, especially in gene transfer work and viral vector identification, could make gene therapy for RDS a possibility in the future.
Collapse
Affiliation(s)
- Kenneth Blum
- Department of Psychiatry & McKnight Brain Institute, University of Florida College of Medicine , Gainesville, FL , USA
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Herman AI, DeVito EE, Jensen KP, Sofuoglu M. Pharmacogenetics of nicotine addiction: role of dopamine. Pharmacogenomics 2015; 15:221-34. [PMID: 24444411 DOI: 10.2217/pgs.13.246] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The neurotransmitter dopamine (DA) plays a central role in addictive disorders, including nicotine addiction. Specific DA-related gene variants have been studied to identify responsiveness to treatment for nicotine addiction. Genetic variants in DRD2, DRD4, ANKK1, DAT1, COMT and DBH genes show some promise in informing personalized prescribing of smoking cessation pharmacotherapies. However, many trials studying these variants had small samples, used retrospective design or were composed of mainly self-identified Caucasian individuals. Furthermore, many of these studies lacked a comprehensive measurement of nicotine metabolism rate, did not assess the roles of sex or the menstrual cycle, and did not investigate the role of rare variants and/or epigenetic factors. Future work should be conducted addressing these limitations to more effectively utilize DA genetic information to unlock the potential of smoking cessation pharmacogenetics.
Collapse
Affiliation(s)
- Aryeh I Herman
- Yale University, School of Medicine, Department of Psychiatry & VA Connecticut Healthcare System, VA Medical Center, 950 Campbell Avenue, West Haven, CT 06516, USA
| | | | | | | |
Collapse
|
13
|
Ohmoto M, Takahashi T, Kubota Y, Kobayashi S, Mitsumoto Y. Genetic influence of dopamine receptor, dopamine transporter, and nicotine metabolism on smoking cessation and nicotine dependence in a Japanese population. BMC Genet 2014; 15:151. [PMID: 25526961 PMCID: PMC4307219 DOI: 10.1186/s12863-014-0151-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 12/11/2014] [Indexed: 01/04/2023] Open
Abstract
Background This study investigated whether polymorphisms of the ankyrin repeat and kinase domain containing 1 gene (ANKK1), which is adjacent to the dopamine D2 receptor gene (DRD2), and the dopamine transporter (SLC6A3) and cytochrome P450 2A6 (CYP2A6) genes influence smoking cessation and nicotine dependence in a Japanese population. In 96 current and former smokers, genotyping frequencies for the ANKK1/DRD2 TaqIA, SLC6A3 VNTR, and CYP2A6 polymorphisms were subjected to chi-square analysis, and regression analyses were used to determine the association of the genotypes of current smokers with a Heavy Smoking Index, in addition to evaluating the effect of the subjects’ smoking history on the association. Results Genotyping results suggested that nicotine dependence among current smokers homozygous for the SLC6A3 10r allele was lower than that of smokers carrying the minor alleles, and that the CYP2A6 polymorphism might mediate this association. Furthermore, the age at which current smokers began smoking might moderate the association between their genetic polymorphisms and nicotine dependence. Conclusions This study provides preliminary findings on the influence of genetic variants on the smoking phenotypes in a Japanese population.
Collapse
Affiliation(s)
- Masanori Ohmoto
- Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa, 920-1181, Japan.
| | - Tatsuo Takahashi
- Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa, 920-1181, Japan.
| | - Yoko Kubota
- Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa, 920-1181, Japan.
| | - Shinjiro Kobayashi
- Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa, 920-1181, Japan.
| | - Yasuhide Mitsumoto
- Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa, 920-1181, Japan.
| |
Collapse
|
14
|
Association between amygdala reactivity and a dopamine transporter gene polymorphism. Transl Psychiatry 2014; 4:e420. [PMID: 25093598 PMCID: PMC4150236 DOI: 10.1038/tp.2014.50] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 04/07/2014] [Accepted: 04/22/2014] [Indexed: 12/29/2022] Open
Abstract
Essential for detection of relevant external stimuli and for fear processing, the amygdala is under modulatory influence of dopamine (DA). The DA transporter (DAT) is of fundamental importance for the regulation of DA transmission by mediating reuptake inactivation of extracellular DA. This study examined if a common functional variable number tandem repeat polymorphism in the 3' untranslated region of the DAT gene (SLC6A3) influences amygdala function during the processing of aversive emotional stimuli. Amygdala reactivity was examined by comparing regional cerebral blood flow, measured with positron emission tomography and [(15)O]water, during exposure to angry and neutral faces, respectively, in a Swedish sample comprising 32 patients with social anxiety disorder and 17 healthy volunteers. In a separate US sample, comprising 85 healthy volunteers studied with blood oxygen level-dependent functional magnetic resonance imaging, amygdala reactivity was assessed by comparing the activity during exposure to threatening faces and neutral geometric shapes, respectively. In both the Swedish and the US sample, 9-repeat carriers displayed higher amygdala reactivity than 10-repeat homozygotes. The results suggest that this polymorphism contributes to individual variability in amygdala reactivity.
Collapse
|
15
|
Zhou Y, Michelhaugh SK, Schmidt CJ, Liu JS, Bannon MJ, Lin Z. Ventral midbrain correlation between genetic variation and expression of the dopamine transporter gene in cocaine-abusing versus non-abusing subjects. Addict Biol 2014; 19:122-31. [PMID: 22026501 DOI: 10.1111/j.1369-1600.2011.00391.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Altered activity of the human dopamine transporter gene (hDAT) is associated with several common and severe brain disorders, including cocaine abuse. However, there is little a priori information on whether such alterations are due to nature (genetic variation) or nurture (human behaviors such as cocaine abuse). This study investigated the correlation between seven markers throughout hDAT and its mRNA levels in postmortem ventral midbrain tissues from 18 cocaine abusers and 18 strictly matched drug-free controls in the African-American population. Here, we show that one major haplotype with the same frequency in cocaine abusers versus drug-free controls displays a 37.1% reduction of expression levels in cocaine abusers compared with matched controls (P=0.0057). The most studied genetic marker, variable number tandem repeats (VNTR) located in Exon 15 (3'VNTR), is not correlated with hDAT mRNA levels. A 5' upstream VNTR (rs70957367) has repeat numbers that are positively correlated with expression levels in controls (r(2)=0.9536, P=0.0235), but this positive correlation disappears in cocaine abusers. The findings suggest that varying hDAT activity is attributable to both genetics and cocaine abuse.
Collapse
Affiliation(s)
- Yanhong Zhou
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA, USA Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA Department of Pathology, Wayne State University School of Medicine, Detroit, MI, USA Department of Statistics, Harvard University, Cambridge, MA, USA
| | | | | | | | | | | |
Collapse
|
16
|
Abstract
The application of genomic medicine to the treatment of nicotine dependence holds great promise for revitalizing the steady decline in smoking rates witnessed in the USA over the past several decades. This paper examines the current knowledge base concerning the use of biomarkers to guide the selection of nicotine dependence treatments. First, we review the neurobiology of nicotine dependence and present evidence that supports its heritability. We then discuss the various studies of pharmacokinetic and pharmacodynamic genes related to therapeutic response. Current evidence suggests that biomarkers of genetic variability in both nicotine metabolism, referred to as the nicotine metabolite ratio, and dopamine genotypes may be useful for guiding treatment selection for nicotine dependence. Barriers to the translation of this research to clinical practice are discussed, as are directions for future research.
Collapse
Affiliation(s)
- Robert A Schnoll
- Pulmonary, Allergy & Critical Care Division, University of Pennsylvania, Presbyterian Medical Center -1 PHI, 51 N 39th Street, Philadelphia, PA 19104, USA.
| | | |
Collapse
|
17
|
Vasic N, Wolf RC, Wolf N, Connemann BJ, Sosic-Vasic Z. [Pharmacotherapeutic treatment strategies for smoking cessation]. DER NERVENARZT 2011; 82:1449-1459. [PMID: 21207000 DOI: 10.1007/s00115-010-3203-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Regular tobacco smoking occurs in about 35% of the male and 25% of the female German population. Individual attempts to independently quit smoking and to remain abstinent for 1 year have been shown to be successful in less than 5% of cases. This rate can be doubled by means of individual consulting and cognitive-behavioral interventions and additional pharmacological treatment might increase abstinence rates up to 25%. Apart from nicotine substitution (e.g. transdermal, oral and inhalative applications) and bupropion, recent studies have shown beneficial effects of varenicline for smoking cessation and abstinence. Varenicline, a selective partial nicotinergic agonist, has been specifically developed for the purpose of smoking cessation. Currently available data suggest that varenicline is more effective compared to nicotine substitution therapy and bupropion, increasing the abstinence likelihood by a factor of 2.3 compared to a placebo. Recent data regarding anti-nicotine vaccines suggest that this approach might yield a comparable treatment outcome and probably even better relapse-preventing effects than conventional psychopharmacological strategies. The first anti-nicotine vaccines are expected to be approved by national authorities within the forthcoming 1-2 years.
Collapse
Affiliation(s)
- N Vasic
- Klinik für Psychiatrie und Psychotherapie III, Universitätsklinikum, Ulm, Deutschland.
| | | | | | | | | |
Collapse
|
18
|
Breitling LP, Müller H, Illig T, Rujescu D, Winterer G, Dahmen N, Nitz B, Raum E, Rothenbacher D, Brenner H. Dopamine-related genes and spontaneous smoking cessation in ever-heavy smokers. Pharmacogenomics 2011; 12:1099-106. [PMID: 21806388 DOI: 10.2217/pgs.11.74] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Several studies have provided evidence for associations of polymorphisms located in and near dopamine-related genes and nicotine dependence and other smoking-related phenotypes, including pharmacogenetic interactions. AIM The purpose of the present work was to examine the association of SNPs in the DOPA decarboxylase (DDC), dopamine receptor D2 (DRD2) and dopamine transporter (SLC6A3) genes with smoking cessation in a large retrospective study featuring approximately 900 cessation events. MATERIALS & METHODS Data originated from the enrollment questionnaire of the epidemiological ESTHER study of community-dwelling adults aged 50-74 years, conducted in the German state of Saarland between July 2000 and December 2002. Restricting the analyses to subjects who reported to have regularly smoked > 20 cigarettes per day at some point in their life, we used survival analysis methods to model the time from initiation of regular smoking to cessation (defined as quitting with abstinence lasting until enrollment) and its relation with eight polymorphisms in the aforementioned genes (five in DDC, two in DRD2 and one in SLC6A3) in 1446 participants. RESULTS Neither individual variants nor DDC haplotypes were associated with the probability of overcoming nicotine dependence in this cohort. CONCLUSION The repeated suggestion of associations between the variants examined and nicotine dependence in previous reports seems to contrast the negative results in the present study. This would appear consistent with the hypothesis that the establishment of regular heavy smoking might abolish associations between genetic determinants of nicotine dependence and nicotine dependence-related phenotypes, in particular the probability of successful smoking cessation.
Collapse
Affiliation(s)
- Lutz P Breitling
- Division of Clinical Epidemiology & Aging Research, German Cancer Research Center (DKFZ), TP4/INF581, 69120 Heidelberg, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Drago A, De Ronchi D, Serretti A. Incomplete coverage of candidate genes: a poorly considered bias. Curr Genomics 2011; 8:476-83. [PMID: 19412419 PMCID: PMC2647155 DOI: 10.2174/138920207783591681] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2007] [Revised: 10/22/2007] [Accepted: 11/01/2007] [Indexed: 12/31/2022] Open
Abstract
Current genetic investigations are performed both on the basis of a rational and biologically based choice of candidate genes and through genome wide scans. Nonetheless, lack of replication is a common problem in psychiatric genetics as well as in other genetic fields. There are a number of reasons for this inconsistency, among them a well known but poorly considered issue is gene coverage. The aim of the present paper is to focus on this well known and defectively deemed bias, especially when a candidate gene approach is chosen. The rational and the technical feasibility of this proposal are discussed as well as a survey of current investigations. The known consistent methodology to fix this bias is also discussed.
Collapse
Affiliation(s)
- Antonio Drago
- Institute of Psychiatry, University of Bologna, Italy
| | | | | |
Collapse
|
20
|
Sturgess JE, George TP, Kennedy JL, Heinz A, Müller DJ. Pharmacogenetics of alcohol, nicotine and drug addiction treatments. Addict Biol 2011; 16:357-76. [PMID: 21362114 DOI: 10.1111/j.1369-1600.2010.00287.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The numerous premature deaths, medical complications and socio-economic repercussions of drug and alcohol addiction suggest that improvements in treatment strategies for addictive disorders are warranted. The use of pharmacogenetics to predict response to medication, side effects and appropriate dosages is relatively new in the field of drug addiction. However, increasing our understanding of the genetic factors influencing these processes may improve the treatment of addiction in the future. We examined the available scientific literature on pharmacogenetic advancements in the field of drug addiction with a focus on alcohol and tobacco to provide a summary of genes implicated in the effectiveness of pharmacotherapy for addiction. In addition, we reviewed pharmacogenetic research on cocaine and heroin dependence. Thus far, the most promising results were obtained for polymorphisms in the OPRM1 and CYP2A6 genes, which have been effective in predicting clinical response to naltrexone in alcoholism and nicotine replacement therapy in smoking, respectively. Opinions differ as to whether pharmacogenetic testing should be implemented in the clinic at this time because clinical utility and cost-effectiveness require further investigation. However, the data summarized in this review demonstrate that pharmacogenetic factors play a role in response to addiction pharmacotherapy and have the potential to aid in the personalization of addiction treatments. Such data may lead to improved cessation rates by allowing physicians to select medications for individuals based, at least in part, on genetic factors that predispose to treatment success or failure rather than on a trial and error basis.
Collapse
Affiliation(s)
- Jessica E Sturgess
- Centre for Addiction and Mental Health, Pharmacogenetics Research Clinic, 250 College Street, Toronto, Ontario, Canada
| | | | | | | | | |
Collapse
|
21
|
Lin Z, Canales JJ, Björgvinsson T, Thomsen MM, Qu H, Liu QR, Torres GE, Caine SB. Monoamine transporters: vulnerable and vital doorkeepers. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:1-46. [PMID: 21199769 PMCID: PMC3321928 DOI: 10.1016/b978-0-12-385506-0.00001-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transporters of dopamine, serotonin, and norepinephrine have been empirically used as medication targets for several mental illnesses in the last decades. These protein-targeted medications are effective only for subpopulations of patients with transporter-related brain disorders. Since the cDNA clonings in early 1990s, molecular studies of these transporters have revealed a wealth of information about the transporters' structure-activity relationship (SAR), neuropharmacology, cell biology, biochemistry, pharmacogenetics, and the diseases related to the human genes encoding these transporters among related regulators. Such new information creates a unique opportunity to develop transporter-specific medications based on SAR, mRNA, DNA, and perhaps transporter trafficking regulation for a number of highly relevant diseases including substance abuse, depression, schizophrenia, and Parkinson's disease.
Collapse
Affiliation(s)
- Zhicheng Lin
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Juan J. Canales
- Department of Psychology, Behavioural Neuroscience, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Thröstur Björgvinsson
- Behavioral Health Partial Hospital and Psychology Internship Programs, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Morgane M. Thomsen
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Hong Qu
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University. Beijing, 100871 China
| | - Qing-Rong Liu
- Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Gonzalo E. Torres
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - S. Barak Caine
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| |
Collapse
|
22
|
Talkowski ME, McCann KL, Chen M, McClain L, Bamne M, Wood J, Chowdari KV, Watson A, Prasad KM, Kirov G, Georgieva L, Toncheva D, Mansour H, Lewis DA, Owen M, O’Donovan M, Papasaikas P, Sullivan P, Ruderfer D, Yao JK, Leonard S, Thomas P, Miyajima F, Quinn J, Lopez AJ, Nimgaonkar VL. Fine-mapping reveals novel alternative splicing of the dopamine transporter. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:1434-47. [PMID: 20957647 PMCID: PMC4575812 DOI: 10.1002/ajmg.b.31125] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 08/04/2010] [Indexed: 01/14/2023]
Abstract
The dopamine transporter gene (SLC6A3, DAT) has been implicated in the pathogenesis of numerous psychiatric and neurodevelopmental disorders, including schizophrenia (SZ). We previously detected association between SZ and intronic SLC6A3 variants that replicated in two independent Caucasian samples, but had no obvious function. In follow-up analyses, we sequenced the coding and intronic regions of SLC6A3 to identify complete linkage disequilibrium patterns of common variations. We genotyped 78 polymorphisms, narrowing the potentially causal region to two correlated clusters of associated SNPs localized predominantly to introns 3 and 4. Our computational analysis of these intronic regions predicted a novel cassette exon within intron 3, designated E3b, which is conserved among primates. We confirmed alternative splicing of E3b in post-mortem human substantia nigra (SN). As E3b introduces multiple in-frame stop codons, the SLC6A3 open reading frame is truncated and the spliced product may undergo nonsense mediated decay. Thus, factors that increase E3b splicing could reduce the amount of unspliced product available for translation. Observations consistent with this prediction were made using cellular assays and in post-mortem human SN. In mini-gene constructs, the extent of splicing is also influenced by at least two common haplotypes, so the alternative splicing was evaluated in relation to SZ risk. Meta-analyses across genome-wide association studies did not support the initial associations and further post-mortem studies did not suggest case-control differences in splicing. These studies do not provide a compelling link to schizophrenia. However, the impact of the alternative splicing on other neuropsychiatric disorders should be investigated. © 2010 Wiley-Liss, Inc.
Collapse
Affiliation(s)
- Michael E. Talkowski
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania,Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania
| | - Kathleen L. McCann
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Michael Chen
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Lora McClain
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Mikhil Bamne
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Joel Wood
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Kodavali V. Chowdari
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Annie Watson
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Konasale M. Prasad
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - George Kirov
- MRC Centre for Neuropsychiatric Genetics and Genomics, Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Cardiff, UK
| | - Lyudmilla Georgieva
- MRC Centre for Neuropsychiatric Genetics and Genomics, Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Cardiff, UK
| | | | - Hader Mansour
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - David A. Lewis
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Michael Owen
- MRC Centre for Neuropsychiatric Genetics and Genomics, Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Cardiff, UK
| | - Michael O’Donovan
- MRC Centre for Neuropsychiatric Genetics and Genomics, Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Cardiff, UK
| | - Panagiotis Papasaikas
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Patrick Sullivan
- Department of Genetics & Carolina Center for Genome Science, University of North Carolina, Chapel Hill, North Carolina
| | - Douglas Ruderfer
- Center for Human Genetic Research, Massachusetts General Hospital and Broad Institute, Boston, Massachusetts
| | - Jeffrey K Yao
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania,VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
| | - Sherry Leonard
- Department of Psychiatry, University of Colorado at Denver, Aurora, Colorado
| | - Pramod Thomas
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Fabio Miyajima
- Division of Human Anatomy and Cell Biology School of Biomedical Sciences, University of Liverpool, Liverpool, UK
| | - John Quinn
- Division of Human Anatomy and Cell Biology School of Biomedical Sciences, University of Liverpool, Liverpool, UK
| | - A. Javier Lopez
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Vishwajit L. Nimgaonkar
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania,Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania,Correspondence: Vishwajit L. Nimgaonkar, Department of Psychiatry and Human Genetics, University of Pittsburgh School of Medicine and Graduate School of Public Health, WPIC, Room 441, 3811 O’Hara St, Pittsburgh, PA 15213
| |
Collapse
|
23
|
Shumay E, Fowler JS, Volkow ND. Genomic features of the human dopamine transporter gene and its potential epigenetic States: implications for phenotypic diversity. PLoS One 2010; 5:e11067. [PMID: 20548783 PMCID: PMC2883569 DOI: 10.1371/journal.pone.0011067] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 05/18/2010] [Indexed: 02/06/2023] Open
Abstract
Human dopamine transporter gene (DAT1 or SLC6A3) has been associated with various brain-related diseases and behavioral traits and, as such, has been investigated intensely in experimental- and clinical-settings. However, the abundance of research data has not clarified the biological mechanism of DAT regulation; similarly, studies of DAT genotype-phenotype associations yielded inconsistent results. Hence, our understanding of the control of the DAT protein product is incomplete; having this knowledge is critical, since DAT plays the major role in the brain's dopaminergic circuitry. Accordingly, we reevaluated the genomic attributes of the SLC6A3 gene that might confer sensitivity to regulation, hypothesizing that its unique genomic characteristics might facilitate highly dynamic, region-specific DAT expression, so enabling multiple regulatory modes. Our comprehensive bioinformatic analyzes revealed very distinctive genomic characteristics of the SLC6A3, including high inter-individual variability of its sequence (897 SNPs, about 90 repeats and several CNVs spell out all abbreviations in abstract) and pronounced sensitivity to regulation by epigenetic mechanisms, as evident from the GC-bias composition (0.55) of the SLC6A3, and numerous intragenic CpG islands (27 CGIs). We propose that this unique combination of the genomic features and the regulatory attributes enables the differential expression of the DAT1 gene and fulfills seemingly contradictory demands to its regulation; that is, robustness of region-specific expression and functional dynamics.
Collapse
Affiliation(s)
- Elena Shumay
- Brookhaven National Laboratory, Medical Department, Upton, New York, United States of America
- * E-mail: (ES); (JSF); (NDV)
| | - Joanna S. Fowler
- Brookhaven National Laboratory, Medical Department, Upton, New York, United States of America
- * E-mail: (ES); (JSF); (NDV)
| | - Nora D. Volkow
- National Institute on Drug Abuse, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (ES); (JSF); (NDV)
| |
Collapse
|
24
|
Wang J, Li MD. Common and unique biological pathways associated with smoking initiation/progression, nicotine dependence, and smoking cessation. Neuropsychopharmacology 2010; 35:702-19. [PMID: 19890259 PMCID: PMC2814000 DOI: 10.1038/npp.2009.178] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Twin and family studies reveal a significant genetic contribution to the risk of smoking initiation and progression (SI/P), nicotine dependence (ND), and smoking cessation (SC). Further, numerous genes have been implicated in these smoking-related behaviors, especially for ND. However, no study has presented a comprehensive and systematic view of the genetic factors associated with these important smoking-related phenotypes. By reviewing the literature on these behaviors, we identified 16, 99, and 75 genes that have been associated with SI/P, ND, and SC, respectively. We then determined whether these genes were enriched in pathways important in the neuronal and brain functions underlying addiction. We identified 9, 21, and 13 pathways enriched in the genes associated with SI/P, ND, and SC, respectively. Among these pathways, four were common to all of the three phenotypes, that is, calcium signaling, cAMP-mediated signaling, dopamine receptor signaling, and G-protein-coupled receptor signaling. Further, we found that serotonin receptor signaling and tryptophan metabolism pathways were shared by SI/P and ND, tight junction signaling pathway was shared by SI/P and SC, and gap junction, neurotrophin/TRK signaling, synaptic long-term potentiation, and tyrosine metabolism were shared between ND and SC. Together, these findings show significant genetic overlap among these three related phenotypes. Although identification of susceptibility genes for smoking-related behaviors is still in an early stage, the approach used in this study has the potential to overcome the hurdles caused by factors such as genetic heterogeneity and small sample size, and thus should yield greater insights into the genetic mechanisms underlying these complex phenotypes.
Collapse
Affiliation(s)
- Ju Wang
- Section of Neurobiology, Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, USA
| | - Ming D Li
- Section of Neurobiology, Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, USA,Section of Neurobiology, Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, 1670 Discovery Drive, Suite 110, Charlottesville, VA 22911, USA. Tel: +434 243 0566; Fax: +434 973 7031; E-mail:
| |
Collapse
|
25
|
McEachin RC, Saccone NL, Saccone SF, Kleyman-Smith YD, Kar T, Kare RK, Ade AS, Sartor MA, Cavalcoli JD, McInnis MG. Modeling complex genetic and environmental influences on comorbid bipolar disorder with tobacco use disorder. BMC MEDICAL GENETICS 2010; 11:14. [PMID: 20102619 PMCID: PMC2823619 DOI: 10.1186/1471-2350-11-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 01/26/2010] [Indexed: 01/15/2023]
Abstract
Background Comorbidity of psychiatric and substance use disorders represents a significant complication in the clinical course of both disorders. Bipolar Disorder (BD) is a psychiatric disorder characterized by severe mood swings, ranging from mania to depression, and up to a 70% rate of comorbid Tobacco Use Disorder (TUD). We found epidemiological evidence consistent with a common underlying etiology for BD and TUD, as well as evidence of both genetic and environmental influences on BD and TUD. Therefore, we hypothesized a common underlying genetic etiology, interacting with nicotine exposure, influencing susceptibility to both BD and TUD. Methods Using meta-analysis, we compared TUD rates for BD patients and the general population. We identified candidate genes showing statistically significant, replicated, evidence of association with both BD and TUD. We assessed commonality among these candidate genes and hypothesized broader, multi-gene network influences on the comorbidity. Using Fisher Exact tests we tested our hypothesized genetic networks for association with the comorbidity, then compared the inferences drawn with those derived from the commonality assessment. Finally, we prioritized candidate SNPs for validation. Results We estimate risk for TUD among BD patients at 2.4 times that of the general population. We found three candidate genes associated with both BD and TUD (COMT, SLC6A3, and SLC6A4) and commonality analysis suggests that these genes interact in predisposing psychiatric and substance use disorders. We identified a 69 gene network that influences neurotransmitter signaling and shows significant over-representation of genes associated with BD and TUD, as well as genes differentially expressed with exposure to tobacco smoke. Twenty four of these genes are known drug targets. Conclusions This work highlights novel bioinformatics resources and demonstrates the effectiveness of using an integrated bioinformatics approach to improve our understanding of complex disease etiology. We illustrate the development and testing of hypotheses for a comorbidity predisposed by both genetic and environmental influences. Consistent with our hypothesis, the selected network models multiple interacting genetic influences on comorbid BD with TUD, as well as the environmental influence of nicotine. This network nominates candidate genes for validation and drug testing, and we offer a panel of SNPs prioritized for follow-up.
Collapse
|
26
|
Kortmann GL, Dobler CJ, Bizarro L, Bau CHD. Pharmacogenetics of smoking cessation therapy. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:17-28. [PMID: 19475569 DOI: 10.1002/ajmg.b.30978] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Nicotine dependence is a major health problem, with a large amount of smoking-related premature deaths and disabilities. The dependence mechanism of nicotine is especially complex and is under strong genetic influence. Smoking cessation is associated with substantial health benefits. Evidence from animal and human studies suggests that genetic polymorphisms influencing pharmacokinetics and pharmacodynamics of nicotine may have great potential for aiding smoking treatment. There are more than 30 association studies and one genome-wide association study (GWAS) between genetic polymorphisms and smoking cessation following nicotine replacement therapy (NRT) and/or bupropion therapy. However, only a few candidate genes or regions were analyzed more than twice and even these genes require additional investigations in different therapeutic schemes. There are a growing number of new pharmacologic options that have not been pharmacogenetically assessed according to published literature. In addition, molecular genetics studies are needed to assess the functional mechanisms of some putative association results. Taken together, the preliminary findings are promising but raise the need for new studies with adequate sample sizes and adjustment for several potential confounding factors frequently neglected, such as comorbidity and sociodemographic factors. The current state of the art in the field encourages an optimist view that personalized treatment approaches may become possible. However, the current scientific evidence still does not support the use of pharmacogenetic tests in routine smoking cessation therapy.
Collapse
Affiliation(s)
- Gustavo L Kortmann
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | | | | |
Collapse
|
27
|
Hill M, Anney RJL, Gill M, Hawi Z. Functional analysis of intron 8 and 3' UTR variable number of tandem repeats of SLC6A3: differential activity of intron 8 variants. THE PHARMACOGENOMICS JOURNAL 2009; 10:442-7. [PMID: 20029387 DOI: 10.1038/tpj.2009.66] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Association studies have found that variation in the dopamine transporter gene (SLC6A3) is important in the susceptibility to attention-deficit hyperactivity disorder (ADHD) and response to methylphenidate treatment. An understanding of the biological mechanisms underlying these associations is still inconclusive. We assessed the relative activity of variable number tandem repeat (VNTR) alleles of SLC6A3 under basal and stimulated cellular conditions, as well as in the presence of pharmacological blockade of the dopamine transporter using gene-reporter constructs. The intron 8 VNTR 5-repeat allele is more active than the 6-repeat allele. In the presence of forskolin, both alleles were significantly induced. Blockade of the dopamine transporter did not influence activity of either allelic construct. No difference in activity between 9- and 10-repeat alleles of the 3'-untranslated region VNTR was observed under any experimental condition. These data suggest that the intron 8 VNTR is a functional variant with an ADHD susceptibility allele having reduced activity. The lack of enhanced allele-specific activity in response to treatment regimes suggests that differential activity under basal conditions is the primary mode of action.
Collapse
Affiliation(s)
- M Hill
- Department of Psychiatry, Neuropsychiatric Genetics Research Group, Trinity College, Dublin, Ireland
| | | | | | | |
Collapse
|
28
|
Schnoll RA, Patterson F. Sex heterogeneity in pharmacogenetic smoking cessation clinical trials. Drug Alcohol Depend 2009; 104 Suppl 1:S94-9. [PMID: 19135319 PMCID: PMC2810256 DOI: 10.1016/j.drugalcdep.2008.11.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 09/03/2008] [Accepted: 11/20/2008] [Indexed: 11/24/2022]
Abstract
Approximately one-quarter of smokers who use treatments for nicotine dependence are able to achieve cessation. However, there is evidence that women do not respond as well to nicotine replacement therapy (NRT) and, perhaps, to bupropion, compared to men. In this contribution to the Special Issue of Drug and Alcohol Dependence concerning Women and Smoking, we begin with a brief overview of data supporting the role of sex in influencing response to NRT and bupropion. Next, we summarize the results of pharmacogenetic smoking cessation clinical trials which assessed sex as a moderator as well. A relatively small number of pharmacogenetic studies of nicotine dependence treatments have been conducted and five studies reported sex effects in these trials. Of these trials, sex moderated the association of genetic variation in drug pharmacokinetics or pharmacodynamics and treatment response. We conclude this paper with a summary and a brief discussion of the major caveats of this literature and priorities for future research.
Collapse
Affiliation(s)
- Robert A. Schnoll
- Corresponding Author/Requests for Reprints: Robert A. Schnoll, Ph.D., Transdisciplinary Tobacco Use Research Center, 3535 Market Street, Suite 4100, University of Pennsylvania, Philadelphia PA, 19104; Phone: 215-746-7143; Fax: 215-746-7140;
| | | |
Collapse
|
29
|
Abstract
We utilized a cohort of 828 treatment-seeking self-identified white cigarette smokers (50% female) to rank candidate gene single nucleotide polymorphisms (SNPs) associated with the Fagerström Test for Nicotine Dependence (FTND), a measure of nicotine dependence which assesses quantity of cigarettes smoked and time- and place-dependent characteristics of the respondent's smoking behavior. A total of 1123 SNPs at 55 autosomal candidate genes, nicotinic acetylcholine receptors and genes involved in dopaminergic function, were tested for association to baseline FTND scores adjusted for age, depression, education, sex, and study site. SNP P-values were adjusted for the number of transmission models, the number of SNPs tested per candidate gene, and their intragenic correlation. DRD2, SLC6A3, and NR4A2 SNPs with adjusted P-values <0.10 were considered sufficiently noteworthy to justify further genetic, bioinformatic, and literature analyses. Each independent signal among the top-ranked SNPs accounted for approximately 1% of the FTND variance in this sample. The DRD2 SNP appears to represent a novel association with nicotine dependence. The SLC6A3 SNPs have previously been shown to be associated with SLC6A3 transcription or dopamine transporter density in vitro, in vivo, and ex vivo. Analysis of SLC6A3 and NR4A2 SNPs identified a statistically significant gene-gene interaction (P=0.001), consistent with in vitro evidence that the NR4A2 protein product (NURR1) regulates SLC6A3 transcription. A community cohort of N=175 multiplex ever-smoking pedigrees (N=423 ever smokers) provided nominal evidence for association with the FTND at these top ranked SNPs, uncorrected for multiple comparisons.
Collapse
|
30
|
David SP, Munafò MR. Genetic variation in the dopamine pathway and smoking cessation. Pharmacogenomics 2009; 9:1307-21. [PMID: 18781857 DOI: 10.2217/14622416.9.9.1307] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Twin and family studies have established that genetic factors account for much of the variation in tobacco dependence. Therefore, identification of genetic variants predictive of successful smoking cessation has implications for the future prospect of personalized smoking cessation therapies. Converging data implicate the dopamine pathway as an important neural substrate for tobacco dependence. Several candidate genes within the dopamine pathway (e.g., DRD2 and COMT) have been reported to be associated with the efficacy of bupropion and nicotine replacement therapy, and others (e.g., SLC6A3 and DRD4) have been reported to be associated with smoking cessation independent of pharmacotherapy. However, few of these candidate genes are present within regions of suggestive or significant linkage or overlap with genome-wide linkage or association studies of tobacco dependence or smoking cessation. Future studies should seek to replicate genome-wide association analyses with individual-level genotyping, and use better-defined smoking cessation phenotypes. Once robust evidence for association is established, which may take several more years, further research into the likely cost-effectiveness, feasibility and acceptability of personalized medicine for smoking cessation will be necessary before it can be translated into practice.
Collapse
Affiliation(s)
- Sean P David
- Brown University Center for Primary Care and Prevention, Department of Family Medicine, The Warren Alpert Medical School of Brown University, Memorial Hospital of Rhode Island, Pawtucket, RI 02860, USA
| | | |
Collapse
|
31
|
Affiliation(s)
- Saul Shiffman
- University of Pittsburgh, Pittsburgh, Pennsylvania, PA, USA.
| |
Collapse
|
32
|
Lerman CE, Schnoll RA, Munafò MR. Genetics and smoking cessation improving outcomes in smokers at risk. Am J Prev Med 2007; 33:S398-405. [PMID: 18021915 PMCID: PMC2170888 DOI: 10.1016/j.amepre.2007.09.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 08/03/2007] [Accepted: 09/17/2007] [Indexed: 10/22/2022]
Abstract
This article reviews evidence supporting the potential utility of a pharmacogenetic approach to the treatment of nicotine dependence. There is substantial evidence that nicotine dependence and smoking persistence are heritable, and are determined by a complex interplay of polygenic and environmental influences. The most robust evidence for specific genetic influences on nicotine dependence is found in studies of genetic variation in nicotine-metabolizing enzymes. Data also support the role of genes in the dopamine and opioid pathways as predictors of dependence and smoking relapse; however, the evidence for genetic associations is not always consistent. Emerging data from pharmacogenetic trials of nicotine-dependence treatment are promising, suggesting that genetic profiles of smokers someday may be used by providers to choose the type, dose, and duration of treatment for individual smokers. However, additional trials including larger and more diverse populations are needed before such data can be translated to practice to reduce smoking prevalence and tobacco-related disease.
Collapse
Affiliation(s)
- Caryn E Lerman
- Transdisciplinary Tobacco Use Research Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
| | | | | |
Collapse
|
33
|
Haddley K, Vasiliou AS, Ali FR, Paredes UM, Bubb VJ, Quinn JP. Molecular genetics of monoamine transporters: relevance to brain disorders. Neurochem Res 2007; 33:652-67. [PMID: 17960477 DOI: 10.1007/s11064-007-9521-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2007] [Indexed: 02/07/2023]
Abstract
We have demonstrated in both the human serotonin transporter gene (5HTT) and the dopamine transporter gene (DAT1) that specific polymorphic variants termed Variable Number Tandem Repeats (VNTRs), which correlate with predisposition to a number of neurological and psychiatric disorders, act as transcriptional regulatory domains. We have demonstrated that these domains can act as both tissue-specific and stimulus-inducible regulators of gene expression. As such they can act to be mechanistically associated with the progression or initiation of a behavioural disorder by altering the level of transporter mRNA, which in turn regulates the concentration of transporter in specific cells or in response to a challenge; chemical, environmental or physiological. The synergistic actions of such transcriptional domains will modulate gene expression. Our hypothesis is that these VNTR variants are one mechanism by which nurture can modify concentrations of neurotransmitters in a differential manner.
Collapse
Affiliation(s)
- K Haddley
- Physiology Laboratory, School of Biomedical Science, University of Liverpool, Liverpool, L69 3BX, England
| | | | | | | | | | | |
Collapse
|
34
|
Lessov-Schlaggar CN, Pergadia ML, Khroyan TV, Swan GE. Genetics of nicotine dependence and pharmacotherapy. Biochem Pharmacol 2007; 75:178-95. [PMID: 17888884 PMCID: PMC2238639 DOI: 10.1016/j.bcp.2007.08.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 08/13/2007] [Accepted: 08/15/2007] [Indexed: 12/22/2022]
Abstract
Nicotine dependence is substantially heritable. Several regions across the genome have been implicated in containing genes that confer liability to nicotine dependence and variation in individual genes has been associated with nicotine dependence. Smoking cessation measures are also heritable, and measured genetic variation is associated with nicotine dependence treatment efficacy. Despite significant strides in the understanding of the relative contribution of genetic and environmental factors to nicotine dependence and treatment, emergent challenges necessitate interdisciplinary coordinated effort for effective problem solving. These challenges include refinement of the nicotine dependence phenotype, better understanding of the dynamic interplay between genes and environment in nicotine dependence etiology, application and development of molecular and statistical methodology that can adequately address vast amounts of data, and continuous translational cross-talk.
Collapse
|
35
|
Stapleton JA, Sutherland G, O'Gara C. Association between dopamine transporter genotypes and smoking cessation: a meta-analysis. Addict Biol 2007; 12:221-6. [PMID: 17508996 DOI: 10.1111/j.1369-1600.2007.00058.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This review assessed the evidence of an association between genotypes of the dopamine transporter (DAT1, SLC6A3) 3' untranslated region (3'UTR) variable number of tandem repeats (VNTR) and smoking cessation. Five studies (seven cohorts) comprising 2155 subjects were included in the meta-analysis. All gave data on the number of smokers who had stopped smoking and the number still smoking for those with one or more variant 9-repeat alleles and other genotypes. Three studies (comprising five cohorts) were cross-sectional population surveys and two were smoking cessation treatment programs with follow-up. Four of the five studies (six of the seven cohorts) showed a trend in favor of cessation when the variant 9-repeat allele was present, although only one study showed a statistically significant effect. The pooled odds ratio in favor of a greater likelihood of cessation for the variant 9-repeat allele was 1.15 [95% confidence interval (CI) = 0.97-1.37]. In a more refined analysis where cohorts within studies were treated as separate samples and adjusted odds ratios were used, the overall pooled odds ratio in favor of cessation with the 9-repeat alleles was 1.20 (95% CI = 1.01-1.43). These results support the hypothesis that the DAT1 3'UTR VNTR polymorphism is associated with smoking cessation. One or more variant 9-repeat alleles relative to the more common 10-repeat allele confers a greater likelihood of cessation, indicative of lower dependence on tobacco. The effect was a 20% increase in the odds of cessation for those with a variant allele.
Collapse
Affiliation(s)
- John A Stapleton
- Tobacco Research Group, Department of Psychological Medicine, Kings College London, Institute of Psychiatry, London, UK.
| | | | | |
Collapse
|