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: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.
Project description:The glutathione S-transferase (GST) gene family codes for enzymes that detoxify xenobiotics by catalyzing the conjugation of xenobiotics to glutathione. Based on reports that inherited copy number variations (CNV) in the genome modulate some GST expression levels and with the knowledge that cigarette smoke contains >3000 xenobiotics, and that the small airway epithelium and alveolar macrophages are involved early in the pathogensis of smoking-induced lung disease, we asked: do germline CNVs modulate GST expression level in the small airway epithelium and alveolar macrophages? Affymetrix HG U133 Plus 2.0 microarrays were used to survey GST gene expression in the small airway epithelium and alveolar macrophages obtained by bronchoscopic brushings from current smokers (n=35) and nonsmokers (n=35). The CNV genotypes of these 70 subjects were determined by Affymetrix Human SNP array 5.0 chips. Sixteen % of subjects had deletions of both GSTM1 alleles. These deletions were associated with reduced GSTM1 mRNA levels in both the small airway epithelium (p<10-7) and alveolar macrophages (p<0.05). Thirty % of subjects had homozygous deletions of GSTT1 with concomitant reduced mRNA levels in both small airway epithelium and alveolar macrophages (p<10-7). In contrast, genes flanking the CNV regions of both GST genes showed no difference in expression level among subjects with and without the GST deletions (p>0.3). Interestingly, GSTT2B, a duplicate gene of GSTT2, exhibited homozygous deletion in blood in 27% of subjects and was not expressed in small airway epithelium in the remainder of subjects but was expressed in alveolar macrophages of heterozygotes and wild type subjects, proportionate to genotype (p<10-3). These data demonstrate that highly prevalent CNV deletions of genes critical to ameliorating smoking-associated xenobiotic-induced damage in the lung can result in significant modulation of the gene expression levels, with the linear relationship of genotype to expression level suggesting minimal compensation of gene expression levels in heterozygotes consistent with GST polymorphisms playing a role in the risk for development of smoking-induced lung disease.
Project description:Nuclear factor erythroid 2-related factor 2 (NFE2L2, Nrf2) is an oxidant responsive transcription factor known to induce phase 2 detoxifying and antioxidant genes to protect cells from oxidative stress. Cigarette smoke, with its large oxidant content, is a major stressor to the small airway epithelium, the cells of which are vulnerable to oxidant damage and consequent malignant transformation. In this study, we assessed the role of cigarette smoke in activation of Nrf2 in the human small airway epithelium in vivo. Fiberoptic bronchoscopy was used to sample a pure population of small airway epithelium in 38 healthy nonsmokers and 45 healthy smokers, and gene expression was assessed using Affymetrix HG-U133 Plus 2.0 microarrays. Compared to that of healthy nonsmokers, Nrf2 protein was significantly activated in the small airway epithelium of healthy normal smokers and localized in the nucleus (p<0.05). Of the human homologs of 201 known murine Nrf2-mediated genes, 13 highly smoking-responsive genes were identified (p<10-4, all comparisons smokers to nonsmokers). Using a “Nrf2-index” to quantify the extent of expression in the small airway epithelium of these 13 known Nrf2 genes, variability in the level of expression was observed among the 45 healthy smokers, but the variability was coordinately modulated among the 13 genes, an observation confirmed by TaqMan quantitative PCR. This variability in the coordinate level of expression of the 13 Nrf2-mediated genes was independent of the smoking history. Based on these observations, the “Nrf2 index” was used to evaluate whether other genes modulated by smoking in the small airway epithelium were also coordinately up- or down- modulated among the 45 healthy smokers. Two genes, pirin (PIR) and UDP glucuronosyltransferase 1 family polypeptide A4 (UGT1A4), not previously known to be modulated by Nrf2 were identified as being coordinately modulated among the 45 smokers. Both genes contain several functional antioxidant response elements in the promoter region. Using an electrophoretic mobility shift assay, these antioxidant response elements in the promoters of PIR and UGT1A4 responded in vitro to activated Nrf2. These observations are consistent with the concept that Nrf2 plays an important role in regulating cellular defenses against smoking in the highly vulnerable small airway epithelium cell population, and that there is variability among the population in the relative Nrf2 responsiveness to a similar oxidant burden. Affymetrix arrays were used to assess gene expression data in small airway epithelium obtained by fiberoptic bronchoscopy of 38 healthy non-smokers and 45 healthy smokers
Project description:Nuclear factor erythroid 2-related factor 2 (NFE2L2, Nrf2) is an oxidant responsive transcription factor known to induce phase 2 detoxifying and antioxidant genes to protect cells from oxidative stress. Cigarette smoke, with its large oxidant content, is a major stressor to the small airway epithelium, the cells of which are vulnerable to oxidant damage and consequent malignant transformation. In this study, we assessed the role of cigarette smoke in activation of Nrf2 in the human small airway epithelium in vivo. Fiberoptic bronchoscopy was used to sample a pure population of small airway epithelium in 38 healthy nonsmokers and 45 healthy smokers, and gene expression was assessed using Affymetrix HG-U133 Plus 2.0 microarrays. Compared to that of healthy nonsmokers, Nrf2 protein was significantly activated in the small airway epithelium of healthy normal smokers and localized in the nucleus (p<0.05). Of the human homologs of 201 known murine Nrf2-mediated genes, 13 highly smoking-responsive genes were identified (p<10-4, all comparisons smokers to nonsmokers). Using a “Nrf2-index” to quantify the extent of expression in the small airway epithelium of these 13 known Nrf2 genes, variability in the level of expression was observed among the 45 healthy smokers, but the variability was coordinately modulated among the 13 genes, an observation confirmed by TaqMan quantitative PCR. This variability in the coordinate level of expression of the 13 Nrf2-mediated genes was independent of the smoking history. Based on these observations, the “Nrf2 index” was used to evaluate whether other genes modulated by smoking in the small airway epithelium were also coordinately up- or down- modulated among the 45 healthy smokers. Two genes, pirin (PIR) and UDP glucuronosyltransferase 1 family polypeptide A4 (UGT1A4), not previously known to be modulated by Nrf2 were identified as being coordinately modulated among the 45 smokers. Both genes contain several functional antioxidant response elements in the promoter region. Using an electrophoretic mobility shift assay, these antioxidant response elements in the promoters of PIR and UGT1A4 responded in vitro to activated Nrf2. These observations are consistent with the concept that Nrf2 plays an important role in regulating cellular defenses against smoking in the highly vulnerable small airway epithelium cell population, and that there is variability among the population in the relative Nrf2 responsiveness to a similar oxidant burden.
Project description:The airways and the alveoli of the human respiratory tract are lined by two distinct types of epithelium. We previously established long-term expanding human lung epithelial organoids from lung tissues and developed a ‘proximal’ differentiation protocol to generate mucociliary airway organoids, yet the derivation of alveolar organoids from adult lung has remained a challenge. Here we defined a ‘distal’ differentiation approach to generate alveolar organoids from the same source that allows the establishment of airway organoids. Alveolar organoids are enriched for AT1 and AT2 cells and functionally simulate the alveolar epithelium. AT2 cells in lung organoids act as the progenitor cells from which alveolar organoids emerge. Moreover, we demonstrate productive SARS-CoV-2 infection of alveolar organoids. We further optimize 2-dimensional (2D) airway organoids. When differentiated under a slightly acidic pH, these 2D airway organoids sustain enhanced viral replication and better recapitulate the high infectivity of SARS-CoV-2. Moreover, the optimized 2D airway organoids can model IgG transcytosis across the airway epithelium. Collectively, we establish a bipotential organoid culture system that can reproducibly expand the entire human respiratory epithelium in vitro for modeling respiratory diseases, including COVID-19.
Project description:Down-regulation of the Notch Differentiation Pathway in the Human Airway Epithelium in Normal Smokers and Smokers with Chronic Obstructive Lung Disease; In cigarette smokers, the toxic components of smoke place the epithelium under the constant stress of a variety of mechanisms of injury, with consequent modulation of airway epithelial regeneration and disordered differentiation. Based on the underlying hypothesis that these airway epithelial changes must involve quantitative changes in genes involved with the regulation of differentiation, we assessed the expression of the Notch pathway, a signaling pathway known to play a fundamental role in the embryonic lung as a gatekeeper for differentiation, in the small airway epithelium of non-smokers, normal smokers, and smokers with COPD. Microarray analysis demonstrated that 45 of the 55 Notch pathway-related genes are expressed in the human adult small airway epithelium and TaqMan quantitative PCR confirmed the expression of key genes in the pathway. TaqMan quantitative PCR analysis of the normal small airway epithelium demonstrated that Delta-like ligand 1 is the most highly expressed Notch ligand, Notch2 and 3 the most highly expressed receptor genes, and Hes1 the predominant downstream effector gene. TaqMan PCR was used to compare gene expression in nonsmokers vs healthy smokers vs smokers with COPD. The data show that some key genes in the ligands, receptors and downstream effectors in the Notch pathway are differentially expressed in smokers, with significant downregulation of a greater number of Notch-related genes in smokers with COPD compared to healthy smokers. These observations are consistent with the hypothesis that the Notch pathway, known to play an important role in lung morphogenesis, also likely plays a role in the adult human airway epithelium, with at least some of the Notch pathway gene expression dysregulated in association with smoking and its related disorder, COPD. Experiment Overall Design: Gene expression in airway epithelial cells of normal non-smokers.
Project description:The earliest morphologic evidence of changes in the airways associated with chronic cigarette smoking is in the small airways. To help understand how smoking modifies small airway structure and function, we developed a strategy using fiberoptic bronchoscopy and brushing to sample the human small airway (10th-12th order) bronchial epithelium to assess gene expression (Affymetrix HG-U133A array) in phenotypically normal smokers (n=6, 24 ± 4 pack-yr) compared to matched non-smokers (n=5). Compared to samples from the large (2nd to 3rd order) bronchi, the small airway samples had a higher proportion of ciliated cells, but less basal, undifferentiated, and secretory cells. The small, but not large, airway samples included Clara cells, a cell found only in the small airway epithelium, and the small, but not the large, airway epithelium expressed genes for the surfactant apoproteins. Despite the fact that the smokers were phenotypically normal, analysis of the small airway epithelium of the smokers compared to the non-smokers demonstrated up- and -down-regulation of genes in multiple categories relevant to the pathogenesis of chronic obstructive lung disease (COPD), including genes coding for cytokines/innate immunity, apoptosis, pro-fibrosis, mucin, responses to oxidants and xenobiotics, antiproteases and general cellular processes. In the context that COPD starts in the small airways, these changes in gene expression in the small airway epithelium in phenotypically normal smokers are candidates for the development of therapeutic strategies to prevent the onset of COPD. Experiment Overall Design: 6 smokers Experiment Overall Design: 5 non-smokers Experiment Overall Design: no replicates
Project description:The earliest morphologic evidence of changes in the airways associated with chronic cigarette smoking is in the small airways. To help understand how smoking modifies small airway structure and function, we developed a strategy using fiberoptic bronchoscopy and brushing to sample the human small airway (10th-12th order) bronchial epithelium to assess gene expression (Affymetrix HG-U133A array) in phenotypically normal smokers (n=6, 24 ± 4 pack-yr) compared to matched non-smokers (n=5). Compared to samples from the large (2nd to 3rd order) bronchi, the small airway samples had a higher proportion of ciliated cells, but less basal, undifferentiated, and secretory cells. The small, but not large, airway samples included Clara cells, a cell found only in the small airway epithelium, and the small, but not the large, airway epithelium expressed genes for the surfactant apoproteins. Despite the fact that the smokers were phenotypically normal, analysis of the small airway epithelium of the smokers compared to the non-smokers demonstrated up- and -down-regulation of genes in multiple categories relevant to the pathogenesis of chronic obstructive lung disease (COPD), including genes coding for cytokines/innate immunity, apoptosis, pro-fibrosis, mucin, responses to oxidants and xenobiotics, antiproteases and general cellular processes. In the context that COPD starts in the small airways, these changes in gene expression in the small airway epithelium in phenotypically normal smokers are candidates for the development of therapeutic strategies to prevent the onset of COPD. Keywords: response to cigarette smoking
Project description:Lectins are proteins present on cell surfaces or as shed extracellular proteins that function in innate immune defense as phagocytic receptors to recognize specific bacterial cell wall components. Based on the knowledge that cigarette smoking is associated with increased risk of bacterial infection, we hypothesized that cigarette smoking may modulate the expression of lectin genes in the airway epithelium. Affymetrix HG U133 Plus 2.0 microarrays were used to survey expression of lectin genes in large (3rd to 4th order bronchi) airway epithelium from 9 normal nonsmokers and 20 phenotypic normal smokers and small (10th to 12th order bronchi) airway epithelium from 13 normal nonsmokers and 20 phenotypic normal smokers. From the 72 lectin genes that were surveyed, there were no changes (>2-fold change, p<0.05) in gene expression in either large or small airway epithelium among normal smokers compared to nonsmokers except for a striking down regulation in both large and small airway epithelium of normal smokers of intelectin 1, a recently described lectin that participates in the innate immune response by recognizing and binding to galactofuranosyl residues in the cell walls of bacteria (large airway epithelium, p<0.003; small airway epithelium, p<0.002). TaqMan RT-PCR confirmed the observation that intelectin 1 was down-regulated in both large (p<0.05) and small airway epithelium (p<0.02) of normal smokers compared to normal nonsmokers. Immunohistochemistry assessment of biopsies of the large airway epithelium of normal nonsmokers demonstrated intelectin 1 was expressed in secretory cells, with qualitatively decreased expression in biopsies from normal smokers. Western analysis confirmed the decreased expression of intelectin 1 in airway epithelium of normal smokers compared to normal nonsmokers (p<0.02). Finally, compared to normal nonsmokers, intelectin 1 expression was decreased in small airway epithelium of smokers with early COPD (n= 13, p<0.001) and smokers with established COPD (n= 14, p<0.001), in a fashion similar to that of normal smokers. In the context that intelectin 1 is an epithelial molecule that likely plays a role in defense against bacteria, the down regulation of expression of intelectin 1 in response to cigarette smoking may contribute to the increase in susceptibility to infections observed in smokers, including those with COPD. Keywords: COPD Comparison of gene expression in airway epithelial cells of normal non-smokers, phenotypic normal smokers, smokers with early COPD, and smokers with COPD.