Project description:Background: Healthy individuals exposed to low levels of cigarette smoke have a decrement in lung function and higher risk for lung disease compared to unexposed individuals. We hypothesized that healthy individuals exposed to low levels of tobacco smoke must have biologic changes in the small airway epithelium compared to healthy unexposed individuals. Methods: Small airway epithelium was obtained by bronchoscopy from 121 individuals; microarrays assessed genome wide gene expression, and urine nicotine and cotinine were used to categorized subjects as “nonsmokers,” “active smokers,” and “low exposure.” The gene expression data was used to determine the threshold and ID50 of urine nicotine and cotinine at which the small airway epithelium showed abnormal responses. Results: There was no threshold of urine nicotine without an abnormal small airway epithelial response, and only a slightly above detectable threshold abnormal response for cotinine. The nicotine ID50 for nicotine was 25 ng/ml and cotinine 104 ng/ml. Conclusions: The small airway epithelium detects and responds to low levels of tobacco smoke with transcriptome modifications. This provides biologic correlates of epidemiologic studies linking low level tobacco smoke exposure to lung health risk, health, identifies genes in the lung cells most sensitive to tobacco smoke and defines thresholds at the lung epithelium responds to inhaled tobacco smoke.
Project description:Background: Healthy individuals exposed to low levels of cigarette smoke have a decrement in lung function and higher risk for lung disease compared to unexposed individuals. We hypothesized that healthy individuals exposed to low levels of tobacco smoke must have biologic changes in the small airway epithelium compared to healthy unexposed individuals. Methods: Small airway epithelium was obtained by bronchoscopy from 121 individuals; microarrays assessed genome wide gene expression, and urine nicotine and cotinine were used to categorized subjects as “nonsmokers,” “active smokers,” and “low exposure.” The gene expression data was used to determine the threshold and ID50 of urine nicotine and cotinine at which the small airway epithelium showed abnormal responses. Results: There was no threshold of urine nicotine without an abnormal small airway epithelial response, and only a slightly above detectable threshold abnormal response for cotinine. The nicotine ID50 for nicotine was 25 ng/ml and cotinine 104 ng/ml. Conclusions: The small airway epithelium detects and responds to low levels of tobacco smoke with transcriptome modifications. This provides biologic correlates of epidemiologic studies linking low level tobacco smoke exposure to lung health risk, health, identifies genes in the lung cells most sensitive to tobacco smoke and defines thresholds at the lung epithelium responds to inhaled tobacco smoke. Affymetrix arrays were used to assess the gene expression data of smoking-responsive genes in the in small airway epithelium obtained by fiberoptic bronchoscopy of 48 healthy non-smokers (non-smoker or Nsaets), 65 healthy smokers (smoker), 7 symptomatic smokers (SYMs) and a healthy occasional smoker (OcSs). YSB and LO contributed equally to the study.
Project description:Smoking is the leading cause of lung cancer death, although only a small percentage of smokers develop the disease. Cigarette smoke exposure is known to cause a field of injury in cells throughout the respiratory tract, and while these airway epithelial cells are morphologically normal, they can undergo genetic alterations in response to cigarette smoke exposure. We used microarrays to analyze the gene expression of epithelial cells in the extrathoracic epithelium, specifically nasal and buccal epithelium, to see if these cells underwent similar genetic alterations in response to tobacco exposure as seen in bronchial epithelial cells as has been previously reported. Keywords: cross sectional
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:Disparate Oxidant-related Gene Expression of Human Small Airway Epithelium Compared to Autologous Alveolar Macrophages in Response to the In Vivo Oxidant Stress of Cigarette Smoking The oxidant burden of cigarette smoking induces lung cell dysfunction, and play a significant role in the pathogenesis of lung disease. Two cell populations directly exposed to the oxidants in cigarette smoke are the small airway epithelium and alveolar macrophages. Of these, the epithelium appears to be more vulnerable to smoking, becoming disordered in differentiation, repair and function, while alveolar macrophages become activated, without becoming diseased. In this context, we asked: for the same individuals, what is the baseline trancriptome of oxidant-related genes in small airway epithelium compared to alveolar macrophages and do the responses of the transcriptome of these 2 cell populations differ substantially to inhaled cigarette smoke? To address these questions we used microarray gene expression and TaqMan analysis to assess the gene expression profile of known oxidant-related genes in paired samples recovered by bronchoscopy from small airway epithelium and alveolar macrophages from the same healthy nonsmokers and normal smokers. Of the 155 oxidant-related genes surveyed, 122 (77%) were expressed in both cell populations in nonsmokers. However, of the genes expressed by both cell populations, oxidant related gene expression levels were higher in alveolar macrophages (67 genes, 43%) than small airway epithelium (37 genes, 24%). There were more oxidant-related genes uniquely expressed in the small airway epithelium (17%), than in alveolar macrophages (5%). In healthy smokers, the majority of oxidant-related genes were expressed in both cell populations, but there were marked differences in the numbers of oxidant-related genes that smoking up- or down-regulated. While smoking up-regulated 15 genes (10%) and down-regulated 7 genes (5%) in the small airway epithelium, smoking had far less effect on alveolar macrophages [only 4 (3%) genes up-regulated, and only 1 (0.6%) down-regulated]. Only a small number of smoking responsive oxidant-related genes overlapped between the two cell types (2 up-regulated, and no down-regulated genes). Consistent with this observation, pathway analysis of smoking-responsive genes in the small airway epithelium showed oxidant-related pathways dominated, but in alveolar macrophages immune-response pathways dominated. Thus, the responses of the oxidant-related transcriptome of cells with an identical genome and exposed to the same oxidant stress of cigarette smoking are very different, with responses of oxidant-related genes of alveolar macrophages far more subdued than that of small airway epithelium, consistent with the clinical observation that, while the small airway epithelium is vulnerable, alveolar macrophages are not "diseased" in response to the oxidant stress of cigarette smoking. Gene expression profiles of known oxidant-related genes in paired samples recovered by bronchoscopy from small airway epithelium and alveolar macrophages from the same healthy nonsmokers and normal smokers.
Project description:Smoking is the leading cause of lung cancer death, although only a small percentage of smokers develop the disease. Cigarette smoke exposure is known to cause a field of injury in cells throughout the respiratory tract, and while these airway epithelial cells are morphologically normal, they can undergo genetic alterations in response to cigarette smoke exposure. We used microarrays to analyze the gene expression of epithelial cells in the extrathoracic epithelium, specifically nasal and buccal epithelium, to see if these cells underwent similar genetic alterations in response to tobacco exposure as seen in bronchial epithelial cells as has been previously reported. Experiment Overall Design: Buccal and nasal epithelial cell samples were collected from healthy current and never smokers. RNA was isolated from these samples and hybridized to Affymetrix microarrays. Gene expression from never smokers was compared to never smoker gene expression from bronchial epithelium as well as expression data from other tissues to determine commonalities in expression patterns in normal extra- and intra-thoracic samples. In addition, gene expression from smokers and nonsmokers was compared in bronchial, nasal, and buccal epithelium to determine similarities in gene expression in these tissues in response to cigarette smoker exposure.
Project description:Along the trachea-bronchial tree, including the small airway region, cigarette smoke exposure induces inflammation, which can exacerbate the development of chronic obstructive pulmonary disease (COPD). The small airway region is known as the primary location of airway blockage in COPD and asthma. Therefore, evaluating exposure impact on the small airway is relevant for risk assessment. Using an in vitro human small airway culture model and a Systems Toxicology approach, this present study reports an assessment of the biological impact of an aerosol from a candidate modified-risk tobacco product, tobacco heating system (THS) 2.2, as compared with 3R4F smoke, at similar nicotine concentratng other functional measures (e.g., cytotoxicity, ciliary beating function, secretion of pro-inflammatory mediators) and histological assessment. The NPA methodology provides not only a qualitative measure of the exposure impact, but also a quantification of the exposure effect: the highest biological impact was observed in cultures 4 h post-exposure to 3R4F smoke at 0.15 mg nicotine/L (100% impact). In contrast, THS2.2 aerosol at similar nicotine concentration, only elicited 15% relative biological impact at 4 h post-exposure in the context of various biological processes modeled in the networks: Cell Fate, Cell Proliferation, Cell Stress, and Inflammatory Process Networks. Consistently, ciliary beating function and culture morphology were not remarkably altered in samples exposed to THS2.2 aerosol, even at nicotine concentration three times that of 3R4F smoke.
Project description:Along the trachea-bronchial tree, including the small airway region, cigarette smoke exposure induces inflammation, which can exacerbate the development of chronic obstructive pulmonary disease (COPD). The small airway region is known as the primary location of airway blockage in COPD and asthma. Therefore, evaluating exposure impact on the small airway is relevant for risk assessment. Using an in vitro human small airway culture model and a Systems Toxicology approach, this present study reports an assessment of the biological impact of an aerosol from a candidate modified-risk tobacco product, tobacco heating system (THS) 2.2, as compared with 3R4F smoke, at similar nicotine concentrating other functional measures (e.g., cytotoxicity, ciliary beating function, secretion of pro-inflammatory mediators) and histological assessment. The NPA methodology provides not only a qualitative measure of the exposure impact, but also a quantification of the exposure effect: the highest biological impact was observed in cultures 4 h post-exposure to 3R4F smoke at 0.15 mg nicotine/L (100% impact). In contrast, THS2.2 aerosol at similar nicotine concentration, only elicited 15% relative biological impact at 4 h post-exposure in the context of various biological processes modeled in the networks: Cell Fate, Cell Proliferation, Cell Stress, and Inflammatory Process Networks. Consistently, ciliary beating function and culture morphology were not remarkably altered in samples exposed to THS2.2 aerosol, even at nicotine concentration three times that of 3R4F smoke.
Project description:Purpose: Globally, many jurisdictions are legalizing or decriminalizing cannabis, creating a potential public health issue that would benefit from experimental evidence to inform policy, government regulations, and user practices. Tobacco smoke exposure science has created a body of knowledge that demonstrates the conclusive negative impacts on respiratory health; similar knowledge remains to be established for cannabis. To address this unmet need, we performed in vitro functional and transcriptomic experiments with a human airway epithelial cell line (Calu-3) exposed to cannabis smoke, with tobacco smoke as a positive control. Results: We demonstrate that cannabis smoke induced functional and transcriptional responses that overlapped with tobacco smoke. Ontology and pathway analysis revealed that cannabis smoke induced DNA replication and oxidative stress responses. Functionally, cannabis smoke impaired epithelial cell barrier function, antiviral responses, and increased inflammatory mediator production. Our study reveals striking similarities between cannabis and tobacco smoke exposure on impairing barrier function, suppressing antiviral pathways, potentiating of pro-inflammatory mediators, and inducing oncogenic and oxidative stress gene expression signatures. LABA/GC intervention in airway epithelial cells exposed to cannabis smoke reduces levels of pro-inflammatory (CXCL8) and antiviral (CXCL10) mediators, while transcriptomic signatures of neutrophil mediated immunity and oxidative stress remain elevated. Conclusions: Collectively our data suggest that cannabis smoke exposure is not innocuous and may possess many of the deleterious properties of tobacco smoke, warranting additional studies to support public policy, government regulations, and user practices.
Project description:The biological impact of an aerosol of a potential modified-risk tobacco product, carbon heated tobacco product 1.2 (CHTP1.2), was comprehensively assessed for the first time in vitro using human small airway and nasal epithelial models following a systems toxicology approach. The potentially reduced effects of CHTP1.2 aerosol exposure were benchmarked against those of 3R4F cigarette smoke at similar nicotine concentrations. Experimental repetitions were conducted for which new batches of small airway and nasal cultures were exposed to CHTP1.2 aerosol or 3R4F smoke for 28 minutes. The biological impacts were determined based on a collection of endpoints including morphology, cytotoxicity, proinflammatory mediator profiles, cytochrome P450 1A1/1B1 activity, global mRNA and microRNA changes and proteome profiles. Alterations in mRNA expression were detected in cultures exposed to CHTP1.2 aerosol, without noticeable morphological changes and cytotoxicity, and minimal impact on proinflammatory mediator and proteome profiles. The changes linked to CHTP1.2 aerosol exposure, when observed, were transient. However, the impact of 3R4F smoke exposure persisted long post-exposure and greater than CHTP1.2 aerosol. Morphological changes were observed only in cultures exposed to 3R4F smoke. The lower biological effects of CHTP1.2 aerosol than 3R4F smoke exposure were observed similarly in both small airway and nasal epithelial cultures.