NFE2L2 pathway polymorphisms and lung function decline in chronic obstructive pulmonary disease.
ABSTRACT: An oxidant-antioxidant imbalance in the lung contributes to the development of chronic obstructive pulmonary disease (COPD) that is caused by a complex interaction of genetic and environmental risk factors. Nuclear erythroid 2-related factor 2 (NFE2L2 or NRF2) is a critical molecule in the lung's defense mechanism against oxidants. We investigated whether polymorphisms in the NFE2L2 pathway affected the rate of decline of lung function in smokers from the Lung Health Study (LHS)(n = 547) and in a replication set, the Vlagtwedde-Vlaardingen cohort (n = 533). We selected polymorphisms in NFE2L2 in genes that positively or negatively regulate NFE2L2 transcriptional activity and in genes that are regulated by NFE2L2. Polymorphisms in 11 genes were significantly associated with rate of lung function decline in the LHS. One of these polymorphisms, rs11085735 in the KEAP1 gene, was previously shown to be associated with the level of lung function in the Vlagtwedde-Vlaardingen cohort but not with decline of lung function. Of the 23 associated polymorphisms in the LHS, only rs634534 in the FOSL1 gene showed a significant association in the Vlagtwedde-Vlaardingen cohort with rate of lung function decline, but the direction of the association was not consistent with that in the LHS. In summary, despite finding several nominally significant polymorphisms in the LHS, none of these associations were replicated in the Vlagtwedde-Vlaardingen cohort, indicating lack of effect of polymorphisms in the NFE2L2 pathway on the rate of decline of lung function.
Project description:The metabolism of xenobiotics plays an essential role in smoking related lung function loss and development of Chronic Obstructive Pulmonary Disease. Nuclear Factor Erythroid 2-Like 2 (NFE2L2 or NRF2) and its cytosolic repressor Kelch-like ECH-associated protein-1 (KEAP1) regulate transcription of enzymes involved in cellular detoxification processes and Nfe2l2-deficient mice develop tobacco-induced emphysema. We assessed the impact of Single Nucleotide Polymorphisms (SNPs) in both genes on the level and longitudinal course of Forced Expiratory Volume in 1 second (FEV1) in the general population.Five NFE2L2 and three KEAP1 tagging SNPs were genotyped in the population-based Doetinchem cohort (n = 1,152) and the independent Vlagtwedde-Vlaardingen cohort (n = 1,390). On average 3 FEV1 measurements during 3 surveys, respectively 7 FEV1 measurements during 8 surveys were present. Linear Mixed Effect models were used to test cross-sectional and longitudinal genetic effects on repeated FEV1 measurements.In the Vlagtwedde-Vlaardingen cohort SNP rs11085735 in KEAP1 was associated with a higher FEV1 level (p = 0.02 for an additive effect), and SNP rs2364723 in NFE2L2 was associated with a lower FEV1 level (p = 0.06). The associations were even more significant in the pooled cohort analysis. No significant association of KEAP1 or NFE2L2 SNPs with FEV1 decline was observed.This is the first genetic study on variations in key antioxidant transcriptional regulators KEAP1 and NFE2L2 and lung function in a general population. It identified 2 SNPs in NFE2L2 and KEAP1 which affect the level of FEV1 in the general population. It additionally shows that NFE2L2 and KEAP1 variations are unlikely to play a role in the longitudinal course of FEV1 in the general population.
Project description:Genome-wide association studies identified single nucleotide polymorphisms (SNPs) in the nicotinic acetylcholine receptors (nAChRs) cluster as a risk factor for nicotine dependency and COPD. We investigated whether SNPs in the nAChR cluster are associated with smoking habits and lung function decline, and if these potential associations are independent of each other. The SNPs rs569207, rs1051730 and rs8034191 in the nAChR cluster were analyzed in the Vlagtwedde-Vlaardingen cohort (n = 1,390) that was followed for 25 years. We used GEE and LME models to analyze the associations of the SNPs with quitting or restarting smoking and with the annual FEV(1) decline respectively. Individuals homozygote (CC) for rs569207 were more likely to quit smoking (OR (95%CI) = 1.58 (1.05-2.38)) compared to wild-type (TT) individuals. Individuals homozygote (TT) for rs1051730 were less likely to quit smoking (0.64 (0.42; 0.97)) compared to wild-type (CC) individuals. None of the SNPs was significantly associated with the annual FEV(1) decline in smokers and ex-smokers. We show that SNPs in the nAChR region are associated with smoking habits such as quitting smoking, but have no significant effect on the annual FEV(1) decline in smokers and ex-smokers, suggesting a potential role of these SNPs in COPD development via smoking habits rather than via direct effects on lung function.
Project description:Two primary chitinases have been identified in humans--acid mammalian chitinase (AMCase) and chitotriosidase (CHIT1). Mammalian chitinases have been observed to affect the host's immune response. The aim of this study was to test for association between genetic variation in the chitinases and phenotypes related to chronic obstructive pulmonary disease (COPD). Polymorphisms in the chitinase genes were selected based on previous associations with respiratory diseases. Polymorphisms that were associated with lung function level or rate of decline in the Lung Health Study (LHS) cohort were analyzed for association with COPD affection status in four other COPD case-control populations. Chitinase activity and protein levels were also related to genotypes. In the caucasian LHS population, the baseline forced expiratory volume in one second (FEV(1)) was significantly different between the AA and GG genotypic groups of the AMCase rs3818822 polymorphism. Subjects with the GG genotype had higher AMCase protein and chitinase activity compared with AA homozygotes. For CHIT1 rs2494303, a significant association was observed between rate of decline in FEV(1) and the different genotypes. In the African American LHS population, CHIT1 rs2494303 and AMCase G339T genotypes were associated with rate of decline in FEV(1). Although a significant effect of chitinase gene alleles was found on lung function level and decline in the LHS, we were unable to replicate the associations with COPD affection status in the other COPD study groups.
Project description:The nuclear factor (erythroid-derived 2)-like 2 (NFE2L2 or NRF2) gene regulates transcription of enzymes involved in cellular detoxification and lipids homeostasis. NFE2L2 is associated with pathophysiology of atherosclerosis and chronic obstructive pulmonary disease (COPD). Therefore we studied the relation between NFE2L2 and all-cause, cardiovascular, and COPD mortality and its associations with triglyceride and cholesterol levels. We genotyped five tagging single nucleotide polymorphisms (SNPs) (rs4243387, rs2364723, rs13001694, rs1806649, and rs6726395) in NFE2L2 in 1,390 subjects from the Vlagtwedde-Vlaardingen cohort. Participants were examined in 1989/1990 and followed up till the vital status evaluation on December 31st, 2008. Associations between SNPs and mortality were estimated by Cox proportional hazards regression, and associations between SNPs and triglyceride and cholesterol levels were tested with linear regression. After 18 yr, 284 (20.4%) subjects had died, 107 from cardiovascular disease and 20 from COPD. Minor allele carriers of rs13001694 had a significantly reduced risk of all-cause mortality compared with wild types: hazard ratio (HR) 0.8 [95% confidence interval (CI) 0.6 to 1.0]. Minor allele carriers of rs2364723 had significantly reduced risk of cardiovascular mortality: HR = 0.5 (95% CI: 0.3-0.7). This result was consistent in stratified analyses: females 0.4 (0.2-0.7), males 0.6 (0.3-0.9), never smokers 0.5 (0.2-1.1), ever smokers 0.5 (0.3-0.8). Minor allele carriers of rs1806649 had a markedly reduced COPD mortality: HR = 0.3 (95% CI: 0.1-0.9). Rs2364723 was associated with lower triglyceride levels. None of the SNPs was associated with cholesterol levels. This study shows for the first time that NFE2L2 is associated with reduced risk of all-cause, cardiovascular and COPD mortality in humans.
Project description:BACKGROUND: Decorin, an extracellular matrix (ECM) proteoglycan, and TGF-beta1 are both involved in lung ECM turnover. Decorin and TGF-beta1 expression are decreased respectively increased in COPD lung tissue. Interestingly, they act as each other's feedback regulator. We investigated whether single nucleotide polymorphisms (SNPs) in decorin and TGF-beta1 underlie accelerated decline in FEV1 and development of COPD in the general population. METHODS: We genotyped 1390 subjects from the Vlagtwedde/Vlaardingen cohort. Lung function was measured every 3 years for a period of 25 years. We tested whether five SNPs in decorin (3'UTR and four intron SNPs) and three SNPs in TGF-beta1 (3'UTR rs6957, C-509T rs1800469 and Leu10Pro rs1982073), and their haplotypes, were associated with COPD (last survey GOLD stage = II). Linear mixed effects models were used to analyze genotype associations with FEV1 decline. RESULTS: We found a significantly higher prevalence of carriers of the minor allele of the TGF-beta1 rs6957 SNP (p = 0.001) in subjects with COPD. Additionally, we found a significantly lower prevalence of the haplotype with the major allele of rs6957 and minor alleles for rs1800469 and rs1982073 SNPs in TGF-beta1 in subjects with COPD (p = 0.030), indicating that this association is due to the rs6957 SNP. TGF-beta1 SNPs were not associated with FEV1 decline. SNPs in decorin, and haplotypes constructed of both TGF-beta1 and decorin SNPs were not associated with development of COPD or with FEV1 decline. CONCLUSION: Our study shows for the first time that SNPs in decorin on its own or in interaction with SNPs in TGF-beta1 do not underlie the disturbed balance in expression between these genes in COPD. TGF-beta1 SNPs are associated with COPD, yet not with accelerated FEV1 decline in the general population.
Project description:Respiratory symptoms are associated with accelerated lung function decline, and increased hospitalization and mortality rates in the general population. Although several environmental risk factors for respiratory symptoms are known, knowledge on genetic risk factors is lacking. We aim to identify genetic variants associated with respiratory symptoms by genome-wide association (GWA) analyses.We conducted the first GWA study on cough, dyspnea and phlegm among 7,976 participants in the LifeLines I cohort and used the LifeLines II cohort (n?=?5,260) and the Vlagtwedde-Vlaardingen cohort (n?=?1,529) for replication.We identified 50 SNPs that were assessed for replication. Rs16918212, located in the alpha-2-macroglobulin pseudogene 1 (A2MP1), was associated with cough in both the identification (odds ratio (OR)?=?0.72, p?=?5.41?×?10-5) and the meta-analyzed replication cohorts (OR?=?0.83, p?= 0.033). No other significant replicated associations were found.Given that only 1 out of 50 SNPs showed significant replication (i.e. 2%) we conclude that we did not find a convincing association between genetic markers and respiratory symptoms. Since, environmental exposures are important risk factors for respiratory symptoms, the next step is to perform a genome-wide interaction (GWI) study to identify genetic susceptibility loci for respiratory symptoms in interaction with known harmful environmental exposures.
Project description:BACKGROUND:Airflow obstruction is a hallmark of chronic obstructive pulmonary disease (COPD), and is defined as either the ratio between forced expiratory volume in one second and forced vital capacity (FEV1/FVC) <?70% or?<?lower limit of normal (LLN). This study aimed to assess the overlap between genome-wide association studies (GWAS) on airflow obstruction using these two definitions in the same population stratified by smoking. METHODS:GWASes were performed in the LifeLines Cohort Study for both airflow obstruction definitions in never-smokers (NS?=?5071) and ever-smokers (ES?=?4855). The FEV1/FVC?<?70% models were adjusted for sex, age, and height; FEV1/FVC?<?LLN models were not adjusted. Ever-smokers models were additionally adjusted for pack-years and current-smoking. The overlap in significantly associated SNPs between the two definitions and never/ever-smokers was assessed using several p-value thresholds. To quantify the agreement, the Pearson correlation coefficient was calculated between the p-values and ORs. Replication was performed in the Vlagtwedde-Vlaardingen study (NS?=?432, ES?=?823). The overlapping SNPs with p <?10-?4 were validated in the Vlagtwedde-Vlaardingen and Rotterdam Study cohorts (NS?=?1966, ES?=?3134) and analysed for expression quantitative trait loci (eQTL) in lung tissue (n =?1087). RESULTS:In the LifeLines cohort, 96% and 93% of the never- and ever-smokers were classified concordantly based on the two definitions. 26 and 29% of the investigated SNPs were overlapping at p <?0.05 in never- and ever-smokers, respectively. At p?<?10-?4 the overlap was 4% and 6% respectively, which could be change findings as shown by simulation studies. The effect estimates of the SNPs of the two definitions correlated strongly, but the p-values showed more variation and correlated only moderately. Similar observations were made in the Vlagtwedde-Vlaardingen study. Two overlapping SNPs in never-smokers (NFYC and FABP7) had the same direction of effect in the validation cohorts and the NFYC SNP was an eQTL for NFYC-AS1. NFYC is a transcription factor that binds to several known COPD genes, and FABP7 may be involved in abnormal pulmonary development. CONCLUSIONS:The definition of airflow obstruction and the population under study may be important determinants of which SNPs are associated with airflow obstruction. The genes FABP7 and NFYC(-AS1) could play a role in airflow obstruction in never-smokers specifically.
Project description:BACKGROUND:Interleukin-6 (IL6) is a pleiotropic pro-inflammatory and immunomodulatory cytokine which probably plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). There is a functional single nucleotide polymorphism (SNP), -174G/C, in the promoter region of IL6. It was hypothesised that IL6 SNPs influence susceptibility for impaired lung function and COPD in smokers. METHODS:Seven and five SNPs in IL6 were genotyped in two nested case-control samples derived from the Lung Health Study (LHS) based on phenotypes of rate of decline of forced expiratory volume in 1 s (FEV(1)) over 5 years and baseline FEV(1) at the beginning of the LHS. Serum IL6 concentrations were measured for all subjects. A partially overlapping panel of nine IL6 SNPs was genotyped in 389 cases of COPD from the National Emphysema Treatment Trial (NETT) and 420 controls from the Normative Aging Study (NAS). RESULTS:In the LHS, three IL6 SNPs were associated with decline in FEV(1) (0.023< or =p< or =0.041 in additive models). Among them, the IL6_-174C allele was associated with a rapid decline in lung function. The association was more significant in a genotype-based analysis (p = 0.006). In the NETT-NAS study, IL6_-174G/C and four other IL6 SNPs, all of which are in linkage disequilibrium with IL6_-174G/C, were associated with susceptibility to COPD (0.01< or =p< or =0.04 in additive genetic models). CONCLUSION:The results suggest that the IL6_-174G/C SNP is associated with a rapid decline in FEV(1) and susceptibility to COPD in smokers.
Project description:The ADAM33 gene is associated with the pathophysiology of Chronic Obstructive Pulmonary Disease (COPD) and atherosclerosis. In this study we investigated all-cause, COPD and cardiovascular mortality, in relation to single nucleotide polymorphisms (SNPs) in ADAM33 (Q_1, S_1, S_2, T_1 and T_2) that were genotyped in 1,390 subjects from the Vlagtwedde/Vlaardingen cohort. Participants were examined at entry in 1989/1990 and followed up till evaluation of the vital status on December 31(st), 2008. Using Cox proportional hazards regression we estimated the risk of the SNPs in relation to mortality, adjusting for gender, age, FEV1, height, place of residence and packyears of smoking. Additionally, we performed stratified analyses according to gender and smoking habits. After 18 years, 284 (20.4%) subjects had died (107 due to cardiovascular disease and 20 due to COPD). Individuals homozygous for the minor allele of SNP T_2 had an increased risk of all-cause and cardiovascular mortality compared to wild types: hazard ratio 3.6 (95% confidence interval 2.0 to 6.7) and 3.4 (1.2 to 9.5) respectively. Individuals homozygous for the minor allele of S_1, S_2, T_2 or Q_1 had a significantly increased risk of COPD mortality. In stratified analyses the risk of all-cause mortality associated with SNP T_2 did not change: females 3.5 (1.5 to 8.3), males 3.1 (1.2 to 7.6), never smokers 3.8 (0.9 to 16.3), ever smokers 3.6 (1.8 to 7.2). This study shows for the first time that ADAM33 is a pleiotropic gene that is associated with all-cause, COPD and cardiovascular mortality, independent of potential confounders.
Project description:<h4>Purpose</h4>There are indications that a history of allergy may offer some protection against cancer. We studied the relation of three objectively determined allergy markers with cancer mortality and hospitalization risk.<h4>Methods</h4>Associations between three allergy markers (number of peripheral blood eosinophil counts, skin test positivity, and serum total IgE) with mortality and hospitalization from any type and four common types of cancer (lung, colorectal, prostate, and breast cancer) were assessed in the Vlagtwedde-Vlaardingen cohort (1965-1990), with follow-up of mortality until 31 December 2008. Hospitalization data were available since 1 January 1995.<h4>Results</h4>There were no significant associations between objective allergy markers and cancer mortality or hospitalization. We found several associations in specific subgroups. A higher number of eosinophils was associated with a decreased risk of colorectal cancer mortality in ever smokers HR (95 % CI) = 0.61 (0.45-0.83) and in males 0.59 (0.42-0.83); however, no overall association was observed 0.84 (0.64-1.09). Skin test positivity was associated with a decreased risk of any cancer mortality only among females 0.59 (0.38-0.91) and showed no overall association 0.83 (0.67-1.04). Serum total IgE levels were associated with an increased risk of lung cancer mortality among females 4.64 (1.04-20.70), but with a decreased risk of cancer hospitalization in ever smokers 0.77 (0.61-0.97) and males 0.72 (0.55-0.93); however, no overall associations were observed [mortality 0.99 (0.79-1.25), and hospitalization 0.86 (0.71-1.04)].<h4>Conclusions</h4>We found no associations between objective allergy markers and cancer in the total population. However, skin test positivity and a high number of eosinophils were associated with a reduced risk to die of cancer in specific subgroups. Hence, it seems important to study specific subgroups defined by gender and smoking habits in order to identify allergy markers of predictive value for cancer mortality.