Project description:Waterpipe (also called hookah, shisha, or narghile) smoking is a common form of tobacco use in the Middle East. Its use is becoming more prevalent in Western societies, especially among young adults as an alternative form of tobacco use to traditional cigarettes. While the risk to cigarette smoking is well documented, the risk to waterpipe smoking is not well defined with limited information on its health impact at the epidemiologic, clinical and biologic levels with respect to lung disease. Based on the knowledge that airway epithelial cell DNA methylation is modified in response to cigarette smoke and in cigarette smoking-related lung diseases, we assessed the impact of light-use water-pipe smoking on DNA methylation of the small airway epithelium (SAE) and whether changes in methylation were linked to the transcriptional output of the cells. Small airway epithelium was obtained from 7 nonsmokers and 7 light-use (2.6 ± 1.7 sessions/wk) waterpipe-only smokers. Genome-wide comparison of SAE DNA methylation of waterpipe smokers to nonsmokers identified 727 probesets differentially methylated (fold-change >1.5, p<0.05) representing 673 unique genes. Dominant pathways associated with these epigenetic changes include those linked to G-protein coupled receptor signaling, aryl hydrocarbon receptor signaling and xenobiotic metabolism signaling, all of which have been associated with cigarette smoking and lung disease. Of the genes differentially methylated, 11.3% exhibited a corresponding significant (p<0.05) change in gene expression with enrichment in pathways related to regulation of mRNA translation and protein synthesis (eIF2 signaling and regulation of eIF4 and p70S6K signaling). Overall, these data demonstrate that light-use waterpipe smoking is associated with epigenetic changes and related transcriptional modifications in the SAE, the cell population demonstrating the earliest pathologic abnormalities associated with chronic cigarette smoking. This study demonstrates that light-use waterpipe smoking in young adults is associated with a broad range of genome-wide DNA methylation-related changes of the SAE impacting a number of genes linked to pathways previously associated with cigarette smoking. Further, many of these methylation-related changes correlate with waterpipe smoking-associated changes in the SAE transcriptome. Together, these data add to the accumulating evidence that waterpipe smoking is harmful, and may lead to lung disease.
Project description:Waterpipe (also called hookah, shisha, or narghile) smoking is a common form of tobacco use in the Middle East. Its use is becoming more prevalent in Western societies, especially among young adults as an alternative form of tobacco use to traditional cigarettes. While the risk to cigarette smoking is well documented, the risk to waterpipe smoking is not well defined with limited information on its health impact at the epidemiologic, clinical and biologic levels with respect to lung disease. Based on the knowledge that airway epithelial cell DNA methylation is modified in response to cigarette smoke and in cigarette smoking-related lung diseases, we assessed the impact of light-use water-pipe smoking on DNA methylation of the small airway epithelium (SAE) and whether changes in methylation were linked to the transcriptional output of the cells. Small airway epithelium was obtained from 7 nonsmokers and 7 light-use (2.6 ± 1.7 sessions/wk) waterpipe-only smokers. Genome-wide comparison of SAE DNA methylation of waterpipe smokers to nonsmokers identified 727 probesets differentially methylated (fold-change >1.5, p<0.05) representing 673 unique genes. Dominant pathways associated with these epigenetic changes include those linked to G-protein coupled receptor signaling, aryl hydrocarbon receptor signaling and xenobiotic metabolism signaling, all of which have been associated with cigarette smoking and lung disease. Of the genes differentially methylated, 11.3% exhibited a corresponding significant (p<0.05) change in gene expression with enrichment in pathways related to regulation of mRNA translation and protein synthesis (eIF2 signaling and regulation of eIF4 and p70S6K signaling). Overall, these data demonstrate that light-use waterpipe smoking is associated with epigenetic changes and related transcriptional modifications in the SAE, the cell population demonstrating the earliest pathologic abnormalities associated with chronic cigarette smoking. This study demonstrates that light-use waterpipe smoking in young adults is associated with a broad range of genome-wide DNA methylation-related changes of the SAE impacting a number of genes linked to pathways previously associated with cigarette smoking. Further, many of these methylation-related changes correlate with waterpipe smoking-associated changes in the SAE transcriptome. Together, these data add to the accumulating evidence that waterpipe smoking is harmful, and may lead to lung disease.
Project description:Aging involves multiple biologically complex processes characterized by a decline in cellular homeostasis over time leading to a loss and impairment of physiological integrity and function. Specific cellular hallmarks of aging include abnormal gene expression patterns, shortened telomeres and associated biological dysfunction. Like all organs, the lung demonstrates both physiological and structural changes with age that result in a progressive decrease in lung function in healthy individuals. Cigarette smoking accelerates lung function decline over time, suggesting smoking accelerates aging of the lung. Based on this data, we hypothesized that cigarette smoking accelerates the aging of the small airway epithelium, the cells that take the initial brunt of inhaled toxins from the cigarette smoke and one of the primary sites of pathology associated with cigarette smoking. Using the sensitive molecular parameters of aging-related gene expression and telomere length, the aging process of the small airway epithelium was assessed in age matched healthy nonsmokers and healthy smokers with no physical manifestation of lung disease or abnormalities in lung function. Analysis of a 73 gene aging signature demonstrated that smoking significantly dysregulates 18 aging-related genes in the small airway epithelium. In an independent cohort of male subjects, smoking significantly reduced telomere length in the small airway epithelium of smokers by 14% compared to nonsmokers. These data provide biologic evidence that prior to the clinical manifestation of lung disease; smoking accelerates aging of the small airway epithelium.
Project description:The initial site of smoking-induced lung disease is the small airway epithelium, which is difficult and time consuming to sample by fiberoptic bronchoscopy. We developed a rapid, office-based procedure to obtain trachea epithelium without conscious sedation from healthy nonsmokers (n=26) and healthy smokers (n=19, 27 ± 15 pack-yr). Gene expression differences [fold-change >1.5, p< 0.01, Benjamini-Hochberg correction] were assessed with Affymetrix microarrays. 1,057 probe sets were differentially expressed in healthy smokers vs nonsmokers, representing >500 genes. Trachea gene expression was compared to an independent group of small airway epithelial samples (n=23 healthy nonsmokers, n=19 healthy smokers, 25 ± 12 pack-yr). The trachea epithelium is more sensitive to smoking, responding with 3-fold more differentially-expressed genes than small airway epithelium. The trachea transcriptome paralleled the small airway epithelium, with 156 of 167 (93%) genes that are significantly up- and down-regulated by smoking in the small airway epithelium showing similar direction and magnitude of response to smoking in the trachea. Trachea epithelium can be obtained without conscious sedation, representing a less invasive surrogate “canary” for smoking-induced changes in the small airway epithelium. This should prove useful in epidemiologic studies correlating gene expression with clinical outcome in assessing smoking-induced lung disease.
Project description:Rationale: Even after quitting smoking, the risk of the development of chronic obstructive pulmonary disease (COPD) and lung cancer remains significantly higher compared to never-smokers. Objectives: Based on the knowledge that COPD and most lung cancers start in the small airway epithelium (SAE), we hypothesized that smoking modulates miRNA expression in the SAE linked to the pathogenesis of smoking-induced airway disease, and that some of these changes persist after smoking cessation. Methods: SAE was collected from 10th to 12th order bronchi using fiberoptic bronchoscopy. Affymetrix miRNA 2.0 arrays were used to assess miRNA expression in the SAE from 10 healthy never-smokers and 10 healthy smokers, before and after they quit for 3 months. Smoking status was determined by urine nicotine and cotinine measurement. Results: There were significant differences in the expression of 34 miRNAs between healthy smokers and healthy never-smokers (p<0.01, fold-change >1.5), with functions associated with lung development, airway epithelium differentiation, inflammation and cancer. After quitting smoking for 3 months, 12 out of the 34 miRNAs did not return to normal levels, with Wnt/β-catenin signaling pathway the top enriched pathway of the target genes of the persistent deregulated miRNAs. Conclusions: In the context that many of these persistent smoking-dependent miRNAs are associated with differentiation, inflammation diseases or lung cancer, it is likely that persistent smoking-related changes in small airway epithelium miRNAs play a role in the subsequent development of these disorders. MicroRNA profiling identified 34 miRNAs up-regulated by cigarette smoking in human small airway epithelium. Even after quitting smoking for 3 months, 12 miRNAs didnât return to normal level.
Project description:Smokers weigh less and have less body fat than non-smokers, and increased body fat and weight gain are observed following smoking cessation. To assess a possible molecular mechanism underlying the inverse association between smoking and body weight, we hypothesized that smoking may induce the expression of a fat depleting gene in the airway epithelium, the cell population that takes the brunt of the stress of cigarette smoke. As a candidate gene we evaluated the expression of alpha2-zinc-glycoprotein1 (AZGP1), a soluble protein that stimulates lipolysis, induces a reduction in body fat in mice and is associated with the cachexia related to cancer, and is known to be expressed in secretory cells of lung epithelium. To assess if smoking upregulates AZGP1 expression, microarray analysis with TaqMan confirmation was used to evaluate large airway epithelial samples obtained by fiberoptic bronchoscopy from 37 normal smokers and 55 normal nonsmokers. Both microarray and TaqMan analysis demonstrated that AZGP1 mRNA levels were higher in the large airway epithelium of normal smokers compared to normal nonsmokers (p<0.05, all comparisons). Western analysis of airway biopsies of smokers compared with nonsmokers demonstrated upregulation of AZGP1 at the protein level, and immunohistochemical analysis demonstrated upregulation of AZGP1 in secretory as well as neuroendocrine cells of smokers. In the context that AZGP1 is involved in lipolysis and fat loss, its overexpression in the airway epithelium of chronic smokers may represent one mechanism for the weight difference in smokers vs nonsmokers. Keywords: Comparison of gene expression in large airway epithleium of normal non-smokers and normal smokers Airway epithelial cells obtained by bronchoscopy with brushing from healthy smokers and healthy non-smokers
Project description:Rationale: Even after quitting smoking, the risk of the development of chronic obstructive pulmonary disease (COPD) and lung cancer remains significantly higher compared to never-smokers. Objectives: Based on the knowledge that COPD and most lung cancers start in the small airway epithelium (SAE), we hypothesized that smoking modulates miRNA expression in the SAE linked to the pathogenesis of smoking-induced airway disease, and that some of these changes persist after smoking cessation. Methods: SAE was collected from 10th to 12th order bronchi using fiberoptic bronchoscopy. Affymetrix miRNA 2.0 arrays were used to assess miRNA expression in the SAE from 10 healthy never-smokers and 10 healthy smokers, before and after they quit for 3 months. Smoking status was determined by urine nicotine and cotinine measurement. Results: There were significant differences in the expression of 34 miRNAs between healthy smokers and healthy never-smokers (p<0.01, fold-change >1.5), with functions associated with lung development, airway epithelium differentiation, inflammation and cancer. After quitting smoking for 3 months, 12 out of the 34 miRNAs did not return to normal levels, with Wnt/β-catenin signaling pathway the top enriched pathway of the target genes of the persistent deregulated miRNAs. Conclusions: In the context that many of these persistent smoking-dependent miRNAs are associated with differentiation, inflammation diseases or lung cancer, it is likely that persistent smoking-related changes in small airway epithelium miRNAs play a role in the subsequent development of these disorders.
Project description:Although smoking-induced lung disease tends to be more common in the upper lobe, it is not known if this results from the skewed distribution of inhaled cigarette smoke or increased susceptibility of the upper lobes to these disorders. The distribution of inhaled cigarette smoke within the lung is complex, depending on lung pressure-volume relationships, gravity, individual smoking habits and the properties of the individual components of cigarette smoke. With the knowledge that the small airway epithelium is the earliest site of smoking-induced lung disease, and that the small airway epithelium is acutely sensitive to inhaled cigarette smoke with significant changes in the up- and down-regulation of hundreds of genes, we compared upper vs lower lobe gene expression in the small airway epithelium of the same cigarette smokers to determine if the gene expression patterns were similar or different. Active smokers (n=11) with early evidence of smoking-induced lung disease (normal spirometry but low diffusing capacity) underwent bronchoscopy and brushing of the small airway epithelium to compare upper vs lower lobe genome-wide gene expression assessed by microarray. Interestingly, cluster and principal component analysis demonstrated that, for each individual, the expression of the known small airway epithelium smoking-responsive genes were remarkably similar as upper vs lower lobe pairs, although, as expected, there were differences in the smoking-induced changes in gene expression from individual to individual. Thus, while there may be topographic differences in the distribution of cigarette smoke, sufficient smoke reaches the upper vs lower lobe small airway epithelium so that, within each smoker, the upper vs lower lobe gene expression are similar. These observations support the concept that the topographic differences in the occurrence of the smoking-induced lung diseases are likely secondary to topographic differences in the susceptibility of the upper vs lower lobes to cigarette smoke, not the topographic differences in distribution of inhaled cigarette smoke.
Project description:Smokers weigh less and have less body fat than non-smokers, and increased body fat and weight gain are observed following smoking cessation. To assess a possible molecular mechanism underlying the inverse association between smoking and body weight, we hypothesized that smoking may induce the expression of a fat depleting gene in the airway epithelium, the cell population that takes the brunt of the stress of cigarette smoke. As a candidate gene we evaluated the expression of alpha2-zinc-glycoprotein1 (AZGP1), a soluble protein that stimulates lipolysis, induces a reduction in body fat in mice and is associated with the cachexia related to cancer, and is known to be expressed in secretory cells of lung epithelium. To assess if smoking upregulates AZGP1 expression, microarray analysis with TaqMan confirmation was used to evaluate large airway epithelial samples obtained by fiberoptic bronchoscopy from 37 normal smokers and 55 normal nonsmokers. Both microarray and TaqMan analysis demonstrated that AZGP1 mRNA levels were higher in the large airway epithelium of normal smokers compared to normal nonsmokers (p<0.05, all comparisons). Western analysis of airway biopsies of smokers compared with nonsmokers demonstrated upregulation of AZGP1 at the protein level, and immunohistochemical analysis demonstrated upregulation of AZGP1 in secretory as well as neuroendocrine cells of smokers. In the context that AZGP1 is involved in lipolysis and fat loss, its overexpression in the airway epithelium of chronic smokers may represent one mechanism for the weight difference in smokers vs nonsmokers. Keywords: Comparison of gene expression in large airway epithleium of normal non-smokers and normal smokers
Project description:Smoking-induced lung disease is one of the most prevalent forms of lung disease but also one of the more diverse. Based on the phenotypic diversity caused by the same environmental stress, we hypothesized that smoking may induce changes in lung cell expression of genes that, with specific variants, are causative of monogenic lung disease, i.e., not that smoking induces a phenocopy of a genetic disease, but smoking may subtly modify the expression of genes known to be associated with genetic disorders with distinct lung disease phenotypes. To assess this hypothesis, and based on the knowledge that most smoking-related disease phenotypes start in the small airway epithelium, we asked: are the genes associated with the monogenic lung disorders expressed in the small airway epithelium, and if so, does smoking alter the expression of these genes? To accomplish this, we examined small airway epithelium expression of 92 genes known to be associated with 17 monogenic lung disorders in 230 samples of small airway epithelium (SAE) obtained from healthy nonsmokers and healthy smokers without any clinical evidence of disease. Of the 86 monogenic disorder-related genes we found expressed in the SAE, strikingly, 37 were significantly differentially expressed in normal smokers compared to normal nonsmokers (p<0.05, Benjamini-Hochberg correction for multiple comparisons). The data demonstrates that the effect of smoking on the transcriptome of small airway epithelium includes significantly altered regulation of the genes responsible for known monogenic disorders.