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: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 small airway epithelium (SAE) the pseudostratified epithelium that covers the majority of the human airway surface from the 6th generation to the alveoli, is the major site of lung disease caused by smoking, and the cell population that exhibits the earliest manifestations of smoking-induced disease. The focus of this study is to use RNA-Seq (massive parallel sequencing technology) to sequence all polyA+ mRNAs expressed by the SAE of healthy nonsmokers to gain new insights into the biology of the SAE, and how these cells respond to cigarette smoke. Taking advantage of RNA-Seq providing quantitative mRNA levels, that data demonstrates that while the SAE shares its transcriptome with many cell types, it has unique characteristics that are enriched in this cell population, with the mostly highly expressed genes (SCGB1A1) characteristics of Clara cells, an airway epithelial cell unique to the human small airways. Among other genes expressed by the SAE are those characteristic of ciliated and mucin-producing cells, basal cells and neuroendocrine cells. The RNA-Seq data includes identification of the highly expressed SAE transcription factors, transmembrane receptors, signaling ligands and growth factors. RNA-Seq permitted quantification of expression of highly homologous gene families, the absolute smoking-induced changes in SAE gene expression, including genes expressed at low levels, and assessment of the effect of smoking on SAE gene splicing. Together, these observations can serve as the baseline for assessment of the dysregulation of SAE gene expression in human airway disease. The small airway epithelium (SAE) is the major site of lung disease caused by smoking, and the cell population that exhibits the earliest manifestations of smoking-induced disease. This study used RNA-Seq to sequence all polyA+ mRNAs expressed by the SAE of 5 healthy nonsmokers to gain new insights into the biology of the SAE, and evaluate how these cells respond to cigarette smoke using 6 healthy smoker samples (SRA029282.1). Taking advantage of RNA-Seq providing quantitative mRNA levels, that data demonstrates that while the SAE shares its transcriptome with many cell types, it has unique characteristics that are enriched in this cell population. Coverage of RNA-Seq expression was also compared to the HG-U133 Plus 2.0 microarray expression of 27 previously published healthy nonsmoker samples presented here.

Dataset Information

Decreased expression of intelectin 1 in the human airway epithelium of smokers compared to nonsmokers.

Publications

Decreased expression of intelectin 1 in the human airway epithelium of smokers compared to nonsmokers.

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