Project description:Modification of Gene Expression of the Small Airway Epithelium in Response to Cigarette Smoking 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 (HG-133 Plus 2.0 array) in phenotypically normal smokers (n=10, 33 ± 7 pack-yr) compared to matched non-smokers (n=12). Even though 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, mucin, response to oxidants and xenobiotics, and general cellular processes. In the context that COPD starts in the small airways, these gene expression changes in the small airway epithelium in phenotypically normal smokers are candidates for the development of therapeutic strategies to prevent the onset of COPD. Keywords: smokers vs 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: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.
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
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. Keywords: non-smokers, airway epithelial cells