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Sved AF, Weeks JJ, Grace AA, Smith TT, Donny EC. Monoamine oxidase inhibition in cigarette smokers: From preclinical studies to tobacco product regulation. Front Neurosci 2022; 16:886496. [PMID: 36051642 PMCID: PMC9424897 DOI: 10.3389/fnins.2022.886496] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/21/2022] [Indexed: 11/13/2022] Open
Abstract
Monoamine oxidase (MAO) activity is reduced in cigarette smokers and this may promote the reinforcing actions of nicotine, thereby enhancing the addictive properties of cigarettes. At present, it is unclear how cigarette smoking leads to MAO inhibition, but preclinical studies in rodents show that MAO inhibition increases nicotine self-administration, especially at low doses of nicotine. This effect of MAO inhibition develops slowly, likely due to plasticity of brain monoamine systems; studies relying on acute MAO inhibition are unlikely to replicate what happens with smoking. Given that MAO inhibition may reduce the threshold level at which nicotine becomes reinforcing, it is important to consider this in the context of very low nicotine content (VLNC) cigarettes and potential tobacco product regulation. It is also important to consider how this interaction between MAO inhibition and the reinforcing actions of nicotine may be modified in populations that are particularly vulnerable to nicotine dependence. In the context of these issues, we show that the MAO-inhibiting action of cigarette smoke extract (CSE) is similar in VLNC cigarettes and cigarettes with a standard nicotine content. In addition, we present evidence that in a rodent model of schizophrenia the effect of MAO inhibition to enhance nicotine self-administration is absent, and speculate how this may relate to brain serotonin systems. These issues are relevant to the MAO-inhibiting effect of cigarette smoking and its implications to tobacco product regulation.
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Affiliation(s)
- Alan F. Sved
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, United States
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
- *Correspondence: Alan F. Sved,
| | - Jillian J. Weeks
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
| | - Anthony A. Grace
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, United States
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
| | - Tracy T. Smith
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Eric C. Donny
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, United States
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Nicotine self-administration with menthol and audiovisual cue facilitates differential packaging of CYP2A6 and cytokines/chemokines in rat plasma extracellular vesicles. Sci Rep 2021; 11:17393. [PMID: 34462474 PMCID: PMC8405708 DOI: 10.1038/s41598-021-96807-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 08/10/2021] [Indexed: 11/16/2022] Open
Abstract
In this study, we investigated whether intravenously self-administered nicotine with menthol and audiovisual cue modulates nicotine-metabolizing CYP2A6, oxidative stress modulators, and cytokines/chemokines in plasma extracellular vesicles (EVs) in rats. We assigned rats to self-administered nicotine with: (a) audiovisual cue (AV), (b) menthol, and (c) menthol and AV cue. We found increased levels of CD9 in plasma EVs after self-administered nicotine with menthol and AV cue. Moreover, expression of CYP2A6 in plasma EVs was significantly increased after self-administered nicotine in response to menthol and AV cue. However, despite an upward trend on SOD1 and catalase, increase was not found to be statistically significant, while total antioxidant capacity was found to be significantly increased in plasma and plasma EVs obtained after self-administered nicotine with menthol and AV cue. Among cytokine and chemokine profiling, we found a significant increase in the levels of MCP-1 after self-administered nicotine with menthol and AV cue and complete packaging of IL-1β in EVs. Taken together, the study provides evidence that nicotine in response to menthol and AV cues can package altered levels of CYP2A6, and cytokines/chemokines in plasma EVs that may contribute to cell–cell communication, nicotine metabolism, and inflammation upon cigarette smoking.
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Roles of Hostility and Depression in the Association between the MAOA Gene Polymorphism and Internet Gaming Disorder. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18136910. [PMID: 34199135 PMCID: PMC8297287 DOI: 10.3390/ijerph18136910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/23/2021] [Accepted: 06/25/2021] [Indexed: 11/16/2022]
Abstract
The metabolism of bioamine in the central nervous system contributes to the development of addiction. We examined the roles of hostility and depression in the association between internet gaming disorder (IGD) and monoamine oxidase-A (MAOA) EcoRV polymorphism (rs1137070). A total of 69 adults with IGD and 138 without IGD were recruited through diagnostic interviewing. We evaluated participants for rs1137070, depression, and hostility. The participants with the TT genotype of rs1137070 had a higher odds ratio of 2.52 (1.37–4.64) for IGD compared with the C carriers. Expressive hostility behavior and hostility cognition mediated the association between rs1137070 and IGD. Indicating lower MAOA activity, the TT genotype predicted IGD and higher expressive hostility behavior and hostility cognition. Expressive hostility behavior and hostility cognition may underline the association between rs1137070 and IGD. Assessment of and intervention for hostility behavior and cognition should be provided to attenuate the risk of IGD, particularly in those with the TT genotype. Further brain imaging or neurobiological studies are required to elucidate the possible mechanism underlying the association between MAOA activity and IGD.
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Ou WC, Huang YC, Huang CL, Lin MH, Chen YC, Chen YJ, Liu CN, Chen MC, Huang CS, Chen PL. Interaction between cytochrome P450 2A6 and Catechol-O-Methyltransferase genes and their association with smoking risk in young men. Behav Brain Funct 2017; 13:8. [PMID: 28472995 PMCID: PMC5418756 DOI: 10.1186/s12993-017-0127-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 04/26/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although some effects of gene-gene interactions on nicotine-dopamine metabolism for smoking behavior have been reported, polymorphisms of cytochrome P450 (CYP) 2A6 and catechol-O-methyltransferase (COMT) have not been studied together to determine their effects on smokers. The aim of this study was to investigate the effects of the interaction between the CYP 2A6 and COMT genes on smoking behavior in young Taiwanese men. RESULTS A self-report questionnaire regarding smoking status was administered to 500 young men. Polymorphisms of the CYP 2A6 and COMT genes as well as urinary nicotine and urinary cotinine levels were determined. The odds ratio for starting smoking was significantly lower in subjects carrying a CYP2A6 low activity/variant COMT rs4680 genotype than in those possessing a CYP2A6 wild-type/variant COMT rs4680 genotype (0.44, 95% confidence interval = 0.19-0.98, P = 0.043). Comparisons of Fagerstrom Test for Nicotine Dependence (FTND), Physiological Cigarette Dependence Scale (PCDS), and Cigarette Withdrawal symptoms (CWS-21) among the smokers with different CYP2A6/COMT polymorphisms were not significantly different. The adjusted urinary nicotine concentrations were not significantly different between the two groups carrying different genotypes. The adjusted urinary cotinine level was significantly different between the COMT rs4680 wild-type group and COMT rs4680 variant group [92.46 ng/μL vs. 118.24 ng/μL (median value), P = 0.041] and between the COMT rs4680 wild-type/COMT rs165599 variant group and COMT rs4680 variant/COMT rs165599 variant group (97.10 ng/μL vs. 122.18 ng/μL, P = 0.022). CONCLUSIONS These findings suggest that a single nucleotide polymorphism (rs4680) of the COMT gene and the interaction between the CYP 2A6 and COMT genes affect smoking status in young Taiwanese men.
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Affiliation(s)
- Wei-Chih Ou
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, No. 666 Buzih Road, Beitun District, Taichung City, 40601, Taiwan
| | - Yi-Chin Huang
- Division of Infectious Diseases, Jen-Ai Hospital, Taichung, Taiwan
| | - Chih-Ling Huang
- Department of Nursing, Chang Jung Christian University, Tainan, Taiwan
| | - Min-Hsuan Lin
- Administration Center for Research and Education, Changhua Christian Hospital, Changhua, Taiwan
| | - Yi-Chun Chen
- Administration Center for Research and Education, Changhua Christian Hospital, Changhua, Taiwan
| | - Yi-Ju Chen
- Company Limited of Ditech Enterprise, Taipei, Taiwan
| | - Chen-Nu Liu
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, No. 666 Buzih Road, Beitun District, Taichung City, 40601, Taiwan
| | - Mei-Chih Chen
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, No. 666 Buzih Road, Beitun District, Taichung City, 40601, Taiwan
| | - Ching-Shan Huang
- Administration Center for Research and Education, Changhua Christian Hospital, Changhua, Taiwan.
| | - Pei-Lain Chen
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, No. 666 Buzih Road, Beitun District, Taichung City, 40601, Taiwan.
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Condoluci A, Mazzara C, Zoccoli A, Pezzuto A, Tonini G. Impact of smoking on lung cancer treatment effectiveness: a review. Future Oncol 2016; 12:2149-61. [PMID: 27424719 DOI: 10.2217/fon-2015-0055] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tobacco smoke contains more than 4000 detectable substances, such as polycyclic aromatic hydrocarbons, nicotine, carbon monoxide and heavy metals, which are considered powerful enzymatic inducers that have notable influence on the efficacy and tolerability of many medications through complex pharmacokinetic and pharmacodynamic interactions. As a result, adjustments of drug dosages are required in smokers, both if they continue to smoke or if they quit after smoking cessation treatment. The purpose of this review is to examine the main drug interactions with tobacco smoke clinically relevant, with a closer look on patients developing oncologic diseases.
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Affiliation(s)
| | - Calogero Mazzara
- Department of Oncology, University Campus Bio-Medico of Rome, Rome, Italy
| | - Alice Zoccoli
- Department of Oncology, University Campus Bio-Medico of Rome, Rome, Italy
| | - Aldo Pezzuto
- Cardiovascular & Pulmonary Department, Sant'Andrea Hospital, Sapienza University, Rome, Italy
| | - Giuseppe Tonini
- Department of Oncology, University Campus Bio-Medico of Rome, Rome, Italy
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Yang X, Chen H, Li S, Wang Q, Pan L, Jia C. Association between monoamine oxidase gene polymorphisms and smoking behavior: A meta-analysis. Drug Alcohol Depend 2015; 153:350-4. [PMID: 26051160 DOI: 10.1016/j.drugalcdep.2015.05.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND A number of studies have researched the association between monoamine oxidase gene (MAO) polymorphisms and smoking behavior, but the conclusion is quite inconsistent. A meta-analysis was conducted to assess the association of MAO-A C1460T, MAO-A VNTR and MAO-B G644A polymorphisms with smoking behavior. METHODS A comprehensive search was performed to identify all eligible studies. Meta-analysis was applied to calculate the pooled effect values and their 95% confidence intervals. Meta-regression and the 'leave one out' sensitivity analysis were used to explore potential sources of heterogeneity. The risk of bias was assessed by the Egger regression asymmetry test. RESULTS 11 articles conformed to the inclusion criteria. The meta-analysis showed T allele in MAO-A C1460T reduced the risk of heavy smoking (OR=0.66, 95% CI: 0.52-0.84; I(2)=0.0%), especially in Caucasians; the active group in MAO-A VNTR increased the likelihood of failed smoking cessation in males (OR=1.49, 95% CI: 1.01-2.22; I(2)=0.0%); A allele in MAO-B G644A reduced the risk of heavy smoking in males (OR=0.20, 95% CI: 0.04-0.98). CONCLUSION Our findings indicate that the low activity of monoamine oxidase gene polymorphisms has a protective effect on smoking cessation and heaviness. Some associations and applications should be further confirmed.
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Affiliation(s)
- Xiaorong Yang
- Department of Epidemiology and Biostatistics, Shandong University, Jinan 250012, Shandong, PR China
| | - Hui Chen
- Department of Epidemiology and Biostatistics, Shandong University, Jinan 250012, Shandong, PR China
| | - Suyun Li
- Department of Epidemiology and Biostatistics, Shandong University, Jinan 250012, Shandong, PR China
| | - Qiang Wang
- Department of Epidemiology and Biostatistics, Shandong University, Jinan 250012, Shandong, PR China
| | - Lulu Pan
- Department of Epidemiology and Biostatistics, Shandong University, Jinan 250012, Shandong, PR China
| | - Chongqi Jia
- Department of Epidemiology and Biostatistics, Shandong University, Jinan 250012, Shandong, PR China.
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Huang CL, Ou WC, Chen PL, Liu CN, Chen MC, Lu CC, Chen YC, Lin MH, Huang CS. Effects of Interaction Between Dopamine D2 Receptor and Monoamine Oxidase A Genes on Smoking Status in Young Men. Biol Res Nurs 2015; 17:422-8. [PMID: 26015071 DOI: 10.1177/1099800415589366] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Although the effect of gene-gene interaction on nicotine-dopamine metabolism for smoking behavior has been reported, polymorphisms of dopamine D2 receptor (DRD2) and monoamine oxidase A (MAOA) have not been simultaneously examined among smokers. In this study, 481 young Taiwanese men completed a self-report questionnaire on smoking status, and data were obtained on polymorphisms of DRD2 rs1800497, DRD2 rs1079597, MAOA rs309850, and MAOA rs1137070, urinary nicotine, and urinary cotinine. In a comparison of 261 current smokers and 220 never smokers, odds ratios (ORs) for the development of smoking in all genotypes were not statistically significant. Among smokers with DRD2 rs1079597 GG//MAOA rs309850 3-repeat, the OR of heavier smoking was 2.67 times higher (95% confidence interval [CI]: [1.08, 6.59], p = .031) and the score on the Fagerstrom test for nicotine dependence was higher (4.26 vs. 2.83) than in those with DRD2 rs1079597 AA//MAOA rs309850 3-repeat. Adjusted urinary cotinine concentration was significantly different between those two groups (median value: 95.83 ng/μl vs. 133.24 ng/μl, respectively, p = .045). These findings suggest that the interaction of DRD2 rs1079597 and MAOA rs309850 3-repeat affects smoking intensity in young Taiwanese men.
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Affiliation(s)
- Chih-Ling Huang
- Department of Nursing, Chang Jung Christian University, Tainan, Taiwan
| | - Wei-Chih Ou
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Pei-Lain Chen
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Chen-Nu Liu
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Mei-Chih Chen
- Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Chia-Chen Lu
- Department of Internal Medicine, Erhlin Christian Hospital, Changhua Christian Medical Foundation, Erhlin, Taiwan
| | - Yi-Chun Chen
- Administration Center of Research and Education, Changhua Christian Hospital, Changhua Christian Medical Foundation, Changhua, Taiwan
| | - Min-Hsuan Lin
- Administration Center of Research and Education, Changhua Christian Hospital, Changhua Christian Medical Foundation, Changhua, Taiwan
| | - Ching-Shan Huang
- Administration Center of Research and Education, Changhua Christian Hospital, Changhua Christian Medical Foundation, Changhua, Taiwan
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Williams SM. Epistasis in the risk of human neuropsychiatric disease. Methods Mol Biol 2015; 1253:71-93. [PMID: 25403528 DOI: 10.1007/978-1-4939-2155-3_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Neuropsychiatric disease represents the ideal class of disease to assess the role of epistasis, as more genes are expressed in the brain than in any other tissue. In this chapter, two well-studied neuropsychiatric diseases are examined, Alzheimer's disease (AD) and schizophrenia, which have been shown to have multiple and, often, replicated interactions that associate with clinical endpoints or related phenotypes. In each case, a single gene is represented in a plurality of epistatic interactions, apolipoprotein E (APOE) for AD and catechol-O-methyltransferase for schizophrenia. Interestingly, of the two, only APOE has clear-cut and consistent evidence for a marginal association. Unraveling the underlying reasons is important in understanding both genetic etiology and architecture as well as how to use genetics to provide better personalized treatments.
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Affiliation(s)
- Scott M Williams
- Department of Genetics, Institute of Quantitative Biomedical Sciences, Geisel School of Medicine, Dartmouth College, 78 College ST, HB 6044, Hanover, NH, 03755, USA,
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Sun Y, Meng S, Li J, Shi J, Lu L. Advances in genetic studies of substance abuse in China. SHANGHAI ARCHIVES OF PSYCHIATRY 2014; 25:199-211. [PMID: 24991158 PMCID: PMC4054556 DOI: 10.3969/j.issn.1002-0829.2013.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Summary The importance of genetic factors in substance addiction has long been established. The rationale for this work is that understanding of the function of addiction genes and delineation of the key molecular pathways of these genes would enhance the development of novel therapeutic targets and biomarkers that could be used in the prevention and management of substance abuse. Over the past few years, there has been a substantial increase in the number of genetic studies conducted on addiction in China; these studies have primarily focused on heroin, alcohol, and nicotine dependence. Most studies of candidate genes have concentrated on the dopamine, opioid, and serotonin systems. A number of genes associated with substance abuse in Caucasians are also risk factors in Chinese, but several novel genes and genetic risk factors associated with substance abuse in Chinese subjects have also been identified. This paper reviews the genetic studies of substance abuse performed by Chinese researchers. Genotypes and alleles related to addictive behavior in Chinese individuals are discussed and the contributions of Chinese researchers to the international corpus of knowledge about the genetic understanding of substance abuse are described.
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Affiliation(s)
- Yan Sun
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Shiqiu Meng
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Jiali Li
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Jie Shi
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Lin Lu
- Institute of Mental Health, Peking University, Beijing, China
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Chen H, Hiler KA, Tolley EA, Matta SG, Sharp BM. Genetic factors control nicotine self-administration in isogenic adolescent rat strains. PLoS One 2012; 7:e44234. [PMID: 22937166 PMCID: PMC3429443 DOI: 10.1371/journal.pone.0044234] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Accepted: 07/30/2012] [Indexed: 11/18/2022] Open
Abstract
Adult cigarette smokers usually become dependent on cigarettes during adolescence. Despite recent advances in addiction genetics, little data delineates the genetic factors that account for the vulnerability of humans to smoke tobacco. We studied the operant nicotine self-administration (SA) behavior of six inbred strains of adolescent male rats (Fisher 344, Brown Norway, Dark Agouti, Spontaneous Hypertensive Rat, Wistar Kyoto and Lewis) and six selected F1 hybrids. All rats were trained to press a lever to obtain food starting on postnatal day (PN) 32, and then nicotine (0.03 mg/kg/infusion, i.v.) reinforcement was made available on PN41-42 (10 consecutive daily 2 h sessions). Of the 12 isogenic strains, Fisher rats self-administered the fewest nicotine infusions (1.45 ± 0.36/d) during the last 3 d, while Lewis rats took the most nicotine (13.0 ± 1.4/d). These strains sorted into high, intermediate and low self-administration groups in 2, 2, and 8 strains, respectively. The influence of heredity on nicotine SA (0.64) is similar to that reported for humans. Therefore, this panel of isogenic rat strains effectively models the overall impact of genetics on the vulnerability to acquire nicotine-reinforced behavior during adolescence. Separate groups of rats responded for food starting on PN41. The correlation between nicotine and food reward was not significant. Hence, the genetic control of the motivation to obtain nicotine is distinctly different from food reward, indicating the specificity of the underlying genetic mechanisms. Lastly, the behavior of F1 hybrids was not predicted from the additive behavior of the parental strains, indicating the impact of significant gene-gene interactions on the susceptibility to nicotine reward. Taken together, the behavioral characteristics of this model indicate its strong potential to identify specific genes mediating the human vulnerability to smoke cigarettes.
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Affiliation(s)
- Hao Chen
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- * E-mail: (HC); (BS)
| | - Katie A. Hiler
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Elizabeth A. Tolley
- Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Shannon G. Matta
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Burt M. Sharp
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- * E-mail: (HC); (BS)
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Tran HN, Siu S, Iribarren C, Udaltsova N, Klatsky AL. Ethnicity and risk of hospitalization for asthma and chronic obstructive pulmonary disease. Ann Epidemiol 2011; 21:615-22. [PMID: 21414801 DOI: 10.1016/j.annepidem.2010.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 10/28/2010] [Accepted: 10/28/2010] [Indexed: 11/17/2022]
Abstract
PURPOSE To identify ethnic differences for risk of hospitalization for asthma and chronic obstructive pulmonary disease (COPD). METHODS We undertook a cohort study with 126,019 participants: 55% whites, 27% blacks, 11% Asians, and 4% Hispanics. To estimate asthma and COPD risk, we used Cox proportional hazards models adjusted for age, sex, body mass index, education, smoking, and alcohol intake. End points were hospitalizations for asthma or COPD. RESULTS Compared with whites, relative risks (RR) with 95% confidence intervals (95% CI) for asthma among other groups were: blacks, 1.7 (1.4-2.0); Hispanics, 0.9 (0.6-1.4); and Asians, 1.6 (1.2-2.1). Among Asians, increased risk was concentrated in Filipino men and women and South Asian men. For COPD, whites were at highest risk; RR of blacks was 0.9 (0.7-1.0); Hispanics, 0.6 (0.3- 0.9); and Asians, 0.4 (0.3-0.6). COPD risk among Asians was lowest in Chinese with RR of 0.3 (0.1-0.5). CONCLUSIONS Ethnic disparities in risk of asthma and COPD as well as between both diseases exist, especially for Asian Americans, who have high asthma risk and low COPD risk. While residual confounding for smoking or other environmental factors could be partially responsible, genetic factors in Asians may be involved in decreased COPD risk.
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Affiliation(s)
- H Nicole Tran
- Department of Medicine, Kaiser Permanente Medical Care Program, Oakland, California 94611, USA.
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Culverhouse RC, Saccone NL, Stitzel JA, Wang JC, Steinbach JH, Goate AM, Schwantes-An TH, Grucza RA, Stevens VL, Bierut LJ. Uncovering hidden variance: pair-wise SNP analysis accounts for additional variance in nicotine dependence. Hum Genet 2011; 129:177-88. [PMID: 21079997 PMCID: PMC3030551 DOI: 10.1007/s00439-010-0911-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 11/01/2010] [Indexed: 02/01/2023]
Abstract
Results from genome-wide association studies of complex traits account for only a modest proportion of the trait variance predicted to be due to genetics. We hypothesize that joint analysis of polymorphisms may account for more variance. We evaluated this hypothesis on a case-control smoking phenotype by examining pairs of nicotinic receptor single-nucleotide polymorphisms (SNPs) using the Restricted Partition Method (RPM) on data from the Collaborative Genetic Study of Nicotine Dependence (COGEND). We found evidence of joint effects that increase explained variance. Four signals identified in COGEND were testable in independent American Cancer Society (ACS) data, and three of the four signals replicated. Our results highlight two important lessons: joint effects that increase the explained variance are not limited to loci displaying substantial main effects, and joint effects need not display a significant interaction term in a logistic regression model. These results suggest that the joint analyses of variants may indeed account for part of the genetic variance left unexplained by single SNP analyses. Methodologies that limit analyses of joint effects to variants that demonstrate association in single SNP analyses, or require a significant interaction term, will likely miss important joint effects.
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Affiliation(s)
- Robert C Culverhouse
- Division of General Medical Sciences, Department of Medicine, Washington University, Saint Louis, MO 63110, USA.
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Li MD, Xu Q, Lou XY, Payne TJ, Niu T, Ma JZ. Association and interaction analysis of variants in CHRNA5/CHRNA3/CHRNB4 gene cluster with nicotine dependence in African and European Americans. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:745-56. [PMID: 19859904 PMCID: PMC2924635 DOI: 10.1002/ajmg.b.31043] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Several previous genome-wide and targeted association studies revealed that variants in the CHRNA5-CHRNA3-CHRNB4 (CHRNA5/A3/B4) gene cluster on chromosome 15 that encode the alpha5, alpha3, and beta4 subunits of the nicotinic acetylcholine receptors (nAChRs) are associated with nicotine dependence (ND) in European Americans (EAs) or others of European origin. Considering the distinct linkage disequilibrium patterns in European and other ethnic populations such as African Americans (AAs), it would be interesting to determine whether such associations exist in other ethnic populations. We performed a comprehensive association and interaction analysis of the CHRNA5/A3/B4 cluster in two ethnic samples to investigate the role of variants in the risk for ND, which was assessed by Smoking Quantity, Heaviness Smoking Index, and Fagerström test for ND. Using a family-based association test, we found a nominal association of single nucleotide polymorphisms (SNPs) rs1317286 and rs8040868 in CHRNA3 with ND in the AA and combined AA and EA samples. Furthermore, we found that several haplotypes in CHRNA5 and CHRNA3 are nominally associated with ND in AA, EA, and pooled samples. However, none of these associations remained significant after correction for multiple testing. In addition, we performed interaction analysis of SNPs within the CHRNA5/A3/B4 cluster using the pedigree-based generalized multifactor dimensionality reduction method and found significant interactions within CHRNA3 and among the three subunit genes in the AA and pooled samples. Together, these results indicate that variants within CHRNA3 and among CHRNA5, CHRNA3, and CHRNB4 contribute significantly to the etiology of ND through gene-gene interactions, although the association of each subunit gene with ND is weak in both the AA and EA samples.
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Affiliation(s)
- Ming D Li
- Department of Psychiatry and Neurobehavioral Sciences, Section of Neurobiology, University of Virginia, 1670 Discovery Drive, Suite 110, Charlottesville, VA 22911, USA.
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Günther F, Wawro N, Bammann K. Neural networks for modeling gene-gene interactions in association studies. BMC Genet 2009; 10:87. [PMID: 20030838 PMCID: PMC2817696 DOI: 10.1186/1471-2156-10-87] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 12/23/2009] [Indexed: 01/17/2023] Open
Abstract
Background Our aim is to investigate the ability of neural networks to model different two-locus disease models. We conduct a simulation study to compare neural networks with two standard methods, namely logistic regression models and multifactor dimensionality reduction. One hundred data sets are generated for each of six two-locus disease models, which are considered in a low and in a high risk scenario. Two models represent independence, one is a multiplicative model, and three models are epistatic. For each data set, six neural networks (with up to five hidden neurons) and five logistic regression models (the null model, three main effect models, and the full model) with two different codings for the genotype information are fitted. Additionally, the multifactor dimensionality reduction approach is applied. Results The results show that neural networks are more successful in modeling the structure of the underlying disease model than logistic regression models in most of the investigated situations. In our simulation study, neither logistic regression nor multifactor dimensionality reduction are able to correctly identify biological interaction. Conclusions Neural networks are a promising tool to handle complex data situations. However, further research is necessary concerning the interpretation of their parameters.
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Affiliation(s)
- Frauke Günther
- University of Bremen, Bremen Institute for Prevention Research and Social Medicine, Linzer Strasse 10, 28359 Bremen, Germany.
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Günther F, Wawro N, Bammann K. Neural networks for modeling gene-gene interactions in association studies. BMC Genet 2009. [PMID: 20030838 DOI: 10.1186/1471‐2156‐10‐87] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Our aim is to investigate the ability of neural networks to model different two-locus disease models. We conduct a simulation study to compare neural networks with two standard methods, namely logistic regression models and multifactor dimensionality reduction. One hundred data sets are generated for each of six two-locus disease models, which are considered in a low and in a high risk scenario. Two models represent independence, one is a multiplicative model, and three models are epistatic. For each data set, six neural networks (with up to five hidden neurons) and five logistic regression models (the null model, three main effect models, and the full model) with two different codings for the genotype information are fitted. Additionally, the multifactor dimensionality reduction approach is applied. RESULTS The results show that neural networks are more successful in modeling the structure of the underlying disease model than logistic regression models in most of the investigated situations. In our simulation study, neither logistic regression nor multifactor dimensionality reduction are able to correctly identify biological interaction. CONCLUSIONS Neural networks are a promising tool to handle complex data situations. However, further research is necessary concerning the interpretation of their parameters.
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Affiliation(s)
- Frauke Günther
- University of Bremen, Bremen Institute for Prevention Research and Social Medicine, Linzer Strasse 10, 28359 Bremen, Germany.
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