scholarly journals Exploration of the role of CHRNA5-A3-B4 genotype in smoking behaviours

2019 ◽  
Author(s):  
Glenda Lassi ◽  
Vanessa Tan ◽  
Liam Mahedy ◽  
Ana Sofia F. Oliveira ◽  
Maddy L. Dyer ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Association Studies ◽  
Strong Association ◽  
Genome Wide Association Studies ◽  
Nicotine Exposure ◽  
Tobacco Exposure ◽  
Smoking Topography ◽  
Never Smokers

AbstractGenome-wide association studies have identified associations between variation at rs16969968/rs1051730 in the CHRNA5–A3–B4 gene cluster and smoking related outcomes. Experiments in rodents have described the nicotinic acetylcholine receptors (nAChRs) subunits encoded by this gene cluster and showed a lack of nicotine aversion in nAChRs deficient animal models. We conducted a nicotine challenge and a smoking topography study in humans, hypothesising that: 1. responses to a nicotine challenge would differ according to the rs16969968/rs1051730 genotype and 2. genotype may influence nicotine intake via smoking topography.We used linear regressions to examine associations between rs16969968/rs1051730 genotype and subjective (questionnaires) and objective (physiological parameters) responses following acute nicotine exposure in never smokers (hypothesis 1) or cigarette smoking in current smokers (hypothesis 2). There was evidence to suggest nicotine exposure increases blood pressure and heart rate, and negatively affects mood, but insufficient evidence that these effects differ by genotype. Carriers of the minor allele following smoking one cigarette, exhibited reduced cravings (b=-2.46, 95% CI -4.87 to - 0.06, p=0.04) and inhaled less smoke per cigarette (b=-0.24, 95% CI - 0.43 to - 0.06, p=0.01) and per puff (b=-0.18, 95% CI -0.32 to -0.01, p=0.02). These results suggest that we need to carefully consider the translational value of the findings of aversion behaviour in nAChRs rodent models, and that deeper inhalation does not explain the strong association between rs16969968/rs1051730 genotype and objective biomarkers of tobacco exposure.

scholarly journals The Oncogenic Functions of Nicotinic Acetylcholine Receptors

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Yue Zhao
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Mammalian Cells ◽  
Acetylcholine Receptors ◽  
Association Studies ◽  
Nicotine Addiction ◽  
Signal Pathways ◽  
Genome Wide Association Studies ◽  
Nicotinic Acetylcholine ◽  
Lung Cancers ◽  
Numerous Cell

Nicotinic acetylcholine receptors (nAChRs) are ion channels that are expressed in the cell membrane of all mammalian cells, including cancer cells. Recent findings suggest that nAChRs not only mediate nicotine addiction in the brain but also contribute to the development and progression of cancers directly induced by nicotine and its derived carcinogenic nitrosamines whereas deregulation of the nAChRs is observed in many cancers, and genome-wide association studies (GWAS) indicate that SNPs nAChRs associate with risks of lung cancers and nicotine addiction. Emerging evidences suggest nAChRs are posited at the central regulatory loops of numerous cell growth and prosurvival signal pathways and also mediate the synthesis and release of stimulatory and inhibitory neurotransmitters induced by their agonists. Thus nAChRs mediated cell signaling plays an important role in stimulating the growth and angiogenic and neurogenic factors and mediating oncogenic signal transduction during cancer development in a cell type specific manner. In this review, we provide an integrated view of nAChRs signaling in cancer, heightening on the oncogenic properties of nAChRs that may be targeted for cancer treatment.

scholarly journals The α5 Nicotinic Acetylcholine Receptor Subunit Differentially Modulates α4β2* and α3β4* Receptors

2020 ◽  
Vol 12 ◽  
Author(s):  
Petra Scholze ◽  
Sigismund Huck
Keyword(s):  
Gene Cluster ◽  
Nicotinic Acetylcholine Receptors ◽  
Association Studies ◽  
Cellular Level ◽  
Chronic Obstructive ◽  
Genome Wide Association Studies ◽  
Nachr Subunit ◽  
Nicotinic Acetylcholine ◽  
Genetically Engineered Mice ◽  
Wide Range

Nicotine, the principal reinforcing compound in tobacco, acts in the brain by activating neuronal nicotinic acetylcholine receptors (nAChRs). This review summarizes our current knowledge regarding how the α5 accessory nAChR subunit, encoded by the CHRNA5 gene, differentially modulates α4β2* and α3β4* receptors at the cellular level. Genome-wide association studies have linked a gene cluster in chromosomal region 15q25 to increased susceptibility to nicotine addiction, lung cancer, chronic obstructive pulmonary disease, and peripheral arterial disease. Interestingly, this gene cluster contains a non-synonymous single-nucleotide polymorphism (SNP) in the human CHRNA5 gene, causing an aspartic acid (D) to asparagine (N) substitution at amino acid position 398 in the α5 nAChR subunit. Although other SNPs have been associated with tobacco smoking behavior, efforts have focused predominantly on the D398 and N398 variants in the α5 subunit. In recent years, significant progress has been made toward understanding the role that the α5 nAChR subunit—and the role of the D398 and N398 variants—plays on nAChR function at the cellular level. These insights stem primarily from a wide range of experimental models, including receptors expressed heterologously in Xenopus oocytes, various cell lines, and neurons derived from human induced pluripotent stem cells (iPSCs), as well as endogenous receptors in genetically engineered mice and—more recently—rats. Despite providing a wealth of available data, however, these studies have yielded conflicting results, and our understanding of the modulatory role that the α5 subunit plays remains incomplete. Here, we review these reports and the various techniques used for expression and analysis in order to examine how the α5 subunit modulates key functions in α4β2* and α3β4* receptors, including receptor trafficking, sensitivity, efficacy, and desensitization. In addition, we highlight the strikingly different role that the α5 subunit plays in Ca2+ signaling between α4β2* and α3β4* receptors, and we discuss whether the N398 α5 subunit variant can partially replace the D398 variant.

Strong Association between Serotonin Transporter 5-HTTVNTR Variant and Psychoactive Substance (Nicotine) Use in the Turkish Cypriot Population

2020 ◽  
Vol 21 (6) ◽  
pp. 466-470
Author(s):  
Emine Kandemis ◽  
Gulten Tuncel ◽  
Ozen Asut ◽  
Sehime G. Temel ◽  
Mahmut C. Ergoren
Keyword(s):  
Serotonin Transporter ◽  
Association Studies ◽  
Strong Association ◽  
Smoking Behavior ◽  
Population Based ◽  
Genome Wide Association Studies ◽  
Genotype Distribution ◽  
Psychological Traits ◽  
Wide Range ◽  
Turkish Cypriot

Background: The use of psychoactive substances is one of the most dangerous social problems worldwide. Nicotine dependence results from the interaction between neurobiological, environmental and genetic factors. Serotonin is a neurotransmitter that has a wide range of central nervous system activities. The serotonin transporter gene has been previously linked to psychological traits. Objective: A variable number of tandem repeats within the serotonin transporter-linked polymorphic gene region are believed to alter the transcriptional efficiency of the 5-HTT gene. Therefore, we aimed to investigate the association between this polymorphic site and smoking behavior in the Turkish Cypriot population. Methods: A total of 259 (100 smokers, 100 non-smokers and 59 ex-smokers) Turkish Cypriots were included in this population-based cross-sectional study. Genomic DNA was extracted from peripheral blood samples and the 5-HTTVNTR2 polymorphisms were determined by the PCR-RFLP. Results: The allelic frequency and genotype distribution results of this study showed a strong association (P<0.0001) between smokers and non-smokers. No statistical significance was found between non-smokers and ex-smokers. Conclusion: This is the first genetic epidemiology study to investigate the allelic frequencies of 5-HTTVNTR2 polymorphisms associated with smoking behavior in the Turkish Cypriot population. Based on the results of this study, genome-wide association studies should be designed for preventive medicine in this population.

Genome-Wide Association Study of Inattention and Hyperactivity–Impulsivity Measured as Quantitative Traits

2013 ◽  
Vol 16 (2) ◽  
pp. 560-574 ◽  
Author(s):  
Jane L. Ebejer ◽  
David L. Duffy ◽  
Julius van der Werf ◽  
Margaret J. Wright ◽  
Grant Montgomery ◽  
...  
Keyword(s):  
Genome Wide Association Study ◽  
Association Studies ◽  
Full Range ◽  
Strong Association ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Community Based ◽  
Normal Behaviour ◽  
Genome Wide ◽  
Inattention And Hyperactivity

Genome-wide association studies (GWAS) of attention-deficit/hyperactivity disorder (ADHD) offer the benefit of a hypothesis-free approach to measuring the quantitative effect of genetic variants on affection status. Generally the findings of GWAS relying on ADHD status have been non-significant, but the one study using quantitative measures of symptoms found SLC9A9 and SLC6A1 were associated with inattention and hyperactivity–impulsivity. Accordingly, we performed a GWAS using quantitative measures of each ADHD subtype measured with the Strengths and Weaknesses of ADHD and Normal Behaviour (SWAN) scale in two community-based samples. This scale captures the full range of attention and kinetic behavior; from high levels of attention and appropriate activity to the inattention and hyperactivity–impulsivity associated with ADHD within two community-based samples. Our discovery sample comprised 1,851 participants (mean age = 22.8 years [4.8]; 50.6% female), while our replication sample comprised 155 participants (mean age = 26.3 years [3.1]; 68.4% females). Age, sex, age × sex, and age2 were included as covariates and the results from each sample were combined using meta-analysis, then analyzed with a gene-based test to estimate the combined effect of markers within genes. We compare our results with markers that have previously been found to have a strong association with ADHD symptoms. Neither the GWAS nor subsequent meta-analyses yielded genome-wide significant results; the strongest effect was observed at rs2110267 (4.62 × 10−7) for symptoms of hyperactivity–impulsivity. The strongest effect in the gene-based test was for GPR139 on symptoms of inattention (6.40 × 10−5). Replication of this study with larger samples will add to our understanding of the genetic etiology of ADHD.

scholarly journals Validation of Susceptibility Loci for Vitiligo Identified by GWAS in the Chinese Han Population

2020 ◽  
Vol 11 ◽  
Author(s):  
Lu Cheng ◽  
Bo Liang ◽  
Xian-Fa Tang ◽  
Xin-Ying Cai ◽  
Hui Cheng ◽  
...  
Keyword(s):  
Association Studies ◽  
Strong Association ◽  
Missense Variant ◽  
Chinese Han Population ◽  
Genome Wide Association Studies ◽  
Nucleotide Polymorphisms ◽  
Susceptibility Loci ◽  
Chinese Han ◽  
Han Population ◽  
Dbsnp Database

Forty-nine susceptible loci have been reported to be significantly associated with vitiligo by genome-wide association studies (GWASs) in European-derived whites. To date, some of these reported susceptibility loci have not yet been validated in the Chinese Han population. The purpose of this study was to examine whether the 16 reported susceptible loci in European-derived whites were associated with vitiligo in the Chinese Han population. Imputation was performed using our previous GWAS dataset by IMPUTE v2.2.2. The 16 imputed top single-nucleotide polymorphisms (SNPs) with suggestive signals, together with the reported SNPs, were genotyped in a total of 2581 patients and 2579 controls by the Sequenom MassARRAY system. PLINK 2.0 software was used to perform association analysis. The dbSNP database, HaploReg, and eQTL data were adopted to annotate the biological function of the SNPs. Finally, four SNPs from three loci were significantly associated with vitiligo, including rs3747517 (P = 1.29 × 10–3, OR = 0.87) in 2q24.2, rs4807000 (P = 7.78 × 10–24, OR = 0.66) and rs6510827 (P = 3.65 × 10–5, OR = 1.19) in 19p13.3, and rs4822024 (P = 6.37 × 10–10, OR = 0.67) in 22q13.2. According to the dbSNP database, rs3747517 is a missense variant of IFIH1, rs4807000 and rs6510827 are located in TICAM1, and rs4822024 is located 6 kb upstream of TEF. Further bioinformatics analysis by HaploReg and eQTL found that rs4807000, rs6510827, and rs4822024 are involved in regulating gene expression. Our study revealed the strong association of 2q24.2 (rs3747517), 19p13.3 (rs4807000, rs6510827), and 22q13.2 (rs4822024) with the risk of vitiligo in the Chinese Han population, which implicates common factors for vitiligo across different ethnicities, and helps expand the understanding of the genetic basis of this disease.

scholarly journals The Impact of the ‘Mis-Peptidome’ on HLA Class I-Mediated Diseases: Contribution of ERAP1 and ERAP2 and Effects on the Immune Response

2020 ◽  
Vol 21 (24) ◽  
pp. 9608
Author(s):  
Valentina Tedeschi ◽  
Giorgia Paldino ◽  
Fabiana Paladini ◽  
Benedetta Mattorre ◽  
Loretta Tuosto ◽  
...  
Keyword(s):  
Inflammatory Diseases ◽  
Association Studies ◽  
Strong Association ◽  
Hla Class I ◽  
Class I ◽  
Mass Spectrometry Analysis ◽  
Genome Wide Association Studies ◽  
Spectrometry Analysis ◽  
Hla Class I Molecules ◽  
The Impact

The strong association with the Major Histocompatibility Complex (MHC) class I genes represents a shared trait for a group of autoimmune/autoinflammatory disorders having in common immunopathogenetic basis as well as clinical features. Accordingly, the main risk factors for Ankylosing Spondylitis (AS), prototype of the Spondyloarthropathies (SpA), the Behçet’s disease (BD), the Psoriasis (Ps) and the Birdshot Chorioretinopathy (BSCR) are HLA-B*27, HLA-B*51, HLA-C*06:02 and HLA-A*29:02, respectively. Despite the strength of the association, the HLA pathogenetic role in these diseases is far from being thoroughly understood. Furthermore, Genome-Wide Association Studies (GWAS) have highlighted other important susceptibility factors such as Endoplasmic Reticulum Aminopeptidase (ERAP) 1 and, less frequently, ERAP2 that refine the peptidome presented by HLA class I molecules to CD8+ T cells. Mass spectrometry analysis provided considerable knowledge of HLA-B*27, HLA-B*51, HLA-C*06:02 and HLA-A*29:02 immunopeptidome. However, the combined effect of several ERAP1 and ERAP2 allelic variants could generate an altered pool of peptides accounting for the “mis-immunopeptidome” that ranges from suboptimal to pathogenetic/harmful peptides able to induce non-canonical or autoreactive CD8+ T responses, activation of NK cells and/or garbling the classical functions of the HLA class I molecules. This review will focus on this class of epitopes as possible elicitors of atypical/harmful immune responses which can contribute to the pathogenesis of chronic inflammatory diseases.

Nicotinic Acetylcholine Receptors in Glucose Homeostasis: The Acute Hyperglycemic and Chronic Insulin-Sensitive Effects of Nicotine Suggest Dual Opposing Roles of the Receptors in Male Mice

Endocrinology ◽  
2014 ◽  
Vol 155 (10) ◽  
pp. 3793-3805 ◽  
Author(s):  
Christine U. Vu ◽  
Jawed A. Siddiqui ◽  
Paul Wadensweiler ◽  
Jiaur R. Gayen ◽  
Ennio Avolio ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Nicotine Exposure ◽  
Dependent Manner ◽  
Nicotinic Acetylcholine ◽  
Nicotine Treatment ◽  
Chronic Nicotine ◽  
Chronic Nicotine Treatment

Abstract Cigarette smoking causes insulin resistance. However, nicotine induces anti-inflammation and improves glucose tolerance in insulin-resistant animal models. Here, we determined the effects of nicotine on glucose metabolism in insulin-sensitive C57BL/J6 mice. Acute nicotine administration (30 min) caused fasting hyperglycemia and lowered insulin sensitivity acutely, which depended on the activation of nicotinic-acetylcholine receptors (nAChRs) and correlated with increased catecholamine secretion, nitric oxide (NO) production, and glycogenolysis. Chlorisondamine, an inhibitor of nAChRs, reduced acute nicotine-induced hyperglycemia. qRT-PCR analysis revealed that the liver and muscle express predominantly β4 &gt; α10 &gt; α3 &gt; α7 and β4 &gt; α10 &gt; β1 &gt; α1 mRNA for nAChR subunits respectively, whereas the adrenal gland expresses β4 &gt; α3 &gt; α7 &gt; α10 mRNA. Chronic nicotine treatment significantly suppressed expression of α3-nAChR (predominant peripheral α-subunit) in liver. Whereas acute nicotine treatment raised plasma norepinephrine (NE) and epinephrine (Epi) levels, chronic nicotine exposure raised only Epi. Acute nicotine treatment raised both basal and glucose-stimulated insulin secretion (GSIS). After chronic nicotine treatment, basal insulin level was elevated, but GSIS after acute saline or nicotine treatment was blunted. Chronic nicotine exposure caused an increased buildup of NO in plasma and liver, leading to decreased glycogen storage, along with a concomitant suppression of Pepck and G6Pase mRNA, thus preventing hyperglycemia. The insulin-sensitizing effect of chronic nicotine was independent of weight loss. Chronic nicotine treatment enhanced PI-3-kinase activities and increased Akt and glycogen synthase kinase (GSK)-3β phosphorylation in an nAChR-dependent manner coupled with decreased cAMP response element–binding protein (CREB) phosphorylation. The latter effects caused suppression of Pepck and G6Pase gene expression. Thus, nicotine causes both insulin resistance and insulin sensitivity depending on the duration of the treatment.

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