Project description:Activation of the human embryonic stem cell (hESC)-signature genes has been observed in various epithelial cancers. In this study, we found that the hESC signature is selectively induced in the airway basal stem/progenitor cell population of healthy smokers (BC-S), with a pat-tern similar to that activated in all major types of human lung cancer. We further identified a subset of 6 BC-S hESC genes, whose coherent overexpression in lung AdCa was associated with reduced lung function, poorer differentiation grade, more advanced tumor stage, remarkably shorter survival and higher frequency of TP53 mutations. BC-S shared with hESC and a consid-erable subset of lung carcinomas a common TP53 inactivation molecular pattern which strongly correlated with the BC-S hESC gene expression. These data provide transcriptome-based evi-dence that smoking-induced reprogramming of airway BC towards the hESC-like phenotype might represent a common early molecular event in the development of aggressive lung carci-nomas in humans. Affymetrix arrays were used to assess gene expression data of genes realted to human embryonic stem cells in large airway epithelium obtained by fiberoptic bronchoscopy of 21 healthy non-smokers and 31 healthy smokers, basal cell culture of large airway epithelium obtained by fiberoptic bronchoscopy of 4 healthy nonsmokers and 4 healthy smokers and cells obtained from tumor tissues of 4 individuals.
Project description:The proximal-distal patterning program determines unique structural and functional properties of proximal and distal airways in the adult lung. Based on the knowledge that remod-eling of distal airways is the major pathologic feature of chronic obstructive pulmonary disease (COPD), and that small airway epithelium (SAE), which covers distal airways, is the primary site of the initial smoking-induced changes relevant to COPD pathogenesis, we hypothesized that in COPD smokers, the SAE transcriptome loses its region-specific biologic identity and takes on the transcriptional pattern of the proximal airways. By analyzing human airway epithelium col-lected by bronchoscopic brushings from proximal and distal airways of healthy smokers, proxi-mal and distal airway epithelial transcriptome signatures were identified. Dramatic smoking-dependent suppression of distal signature paralleled by acquisition of the proximal airway epithe-lial phenotype was found in the SAE of COPD smokers. Distal-proximal re-patterning observed in the SAE of smokers in vivo was reproduced in vitro by stimulating SAE basal cells (BC), the stem/progenitor cells of the SAE, with EGF, a growth factor up-regulated in airway epithelium by smoking. Together, this study identifies distal-proximal SAE re-patterning as a characteristic feature of small airway disordering in COPD smokers potentially driven by EGF/EGFR-mediated reprogramming of SAE BC stem/progenitor cells.
Project description:Activation of the human embryonic stem cell (hESC)-signature genes has been observed in various epithelial cancers. In this study, we found that the hESC signature is selectively induced in the airway basal stem/progenitor cell population of healthy smokers (BC-S), with a pat-tern similar to that activated in all major types of human lung cancer. We further identified a subset of 6 BC-S hESC genes, whose coherent overexpression in lung AdCa was associated with reduced lung function, poorer differentiation grade, more advanced tumor stage, remarkably shorter survival and higher frequency of TP53 mutations. BC-S shared with hESC and a consid-erable subset of lung carcinomas a common TP53 inactivation molecular pattern which strongly correlated with the BC-S hESC gene expression. These data provide transcriptome-based evi-dence that smoking-induced reprogramming of airway BC towards the hESC-like phenotype might represent a common early molecular event in the development of aggressive lung carci-nomas in humans.
Project description:The aldokatoreductases (AKRs) represent a gene superfamily that code for monomeric, soluble NAD(P)H-dependent oxidoreductases that mediate elimination reactions. AKR1B10, an AKR that functions to eliminate retinals, has been observed to be upregulated in squamous metaplasma and non small cell lung cancer, and has been suggested as a diagnostic marker specific to tobacco-related carcinogenesis. In the context of the link of smoking and lung cancer and the enhanced expression of AKR1B10 expression in lung cancer, we hypothesize that enhanced expression of AKR1B10 may be initiated in healthy smokers, prior to the development of any evidence of lung cancer. For this purpose, expression of AKR1B10 was assessed at the mRNA level using microarrays in the large airway epithelium (21 healthy nonsmokers, 31 health smokers) and small airway epithelium (51 healthy nonsmokers, 58 healthy smokers) obtained by fiberoptic bronchoscopy and brushing, as well as assessment in a subset of this population by TaqMan PCR and in endobronchial biopsies by Western analysis and immunohistochemistry. Compared to healthy nonsmokers, ARK1B10 mRNA levels were markedly upregulated in both the large and small airway epithelium of healthy smokers (large airway microarray p<0.0001, small airway p<0.0001; TaqMan large airway, p<0.02, small airway p<0.01). Consistent with the mRNA data, AKR1B10 protein was significantly upregulated in the airway epithelium of healthy smokers as assessed by Western analysis and by immunohistochemistry, with AKR1B10 expressed in both differentiated and basal cells of the normal epithelium. Finally, cigarette smoke extract mediated up-regulation of AKR1B10 in airway epithelial cells in vitro. Thus, smoking per se mediates up-regulation of AKR1B10 expression in the airway epithelium of healthy smokers with no evidence of lung cancer. In the context of these observations, and the link of AKR1B10 to the metabolism of retinals and to lung cancer, the smoking-induced up-regulation of AKR1B10 may be an early process in the multiple events leading to the develop of lung cancer.
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: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
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:Background. The human airway epithelium consists of 4 major cell types: ciliated, secretory, columnar and basal cells. During natural turnover and in response to injury, the airway basal cells function as stem / progenitor cells for the other airway cell types. The objective of this study is to better understand basal cell biology by defining the subset of expressed genes that characterize the signature of human airway epithelial basal cells. Methodology / Principal Findings. Microarrays were used to assess the transcriptome of basal cells purified from the airway epithelium of healthy nonsmokers obtained by bronchial brushings in comparison to the transcriptome of the complete differentiated airway epithelium. This analysis identified the “human airway basal cell signature” as 1,161 unique genes with >5-fold higher expression level in basal cells compared to the differentiated epithelium. The basal cell signature was suppressed when the basal cells differentiated into a ciliated airway epithelium in vitro. The human airway basal cell signature displayed extensive overlap with genes expressed in basal cells from other human tissues and murine airway basal cells. Consistent with self-modulation as well as signaling to other airway cell types, the airway basal cell signature was characterized by genes encoding extracellular matrix components, and growth factors and growth factor receptors, including genes related to EGFR and VEGFR signaling. However, while human airway basal cells share similarity with basal-like cells of other organs, the human airway basal cell signature has features not previously associated with this cell type, including a unique pattern of genes encoding extracellular matrix components, integrins, G protein-coupled receptors, neuroactive ligands and receptors, and ion channels. Conclusion / Significance. The human airway epithelial basal cells signature identified in the present study provides novel insights into the ontogeny, molecular phenotype and biology of the stem / progenitor cells of the human airway epithelium. This study was designed to distinguish the transcriptome of the airway epithelium basal cell from that of differentiated airway epithelium. A basal cell signature was derived and analyzed for functional significance. The signature was also evaluated as basal cells differentiated into ciliated epithelium in vitro.
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. Experiment Overall Design: Tracheal gene expression: matched group of small airway epithelial samples (n=23 healthy non-smokers, n= 19 healthy smokers)
Project description:Rationale: Genome-wide association studies (GWAS) and candidate gene studies have identified a number of loci linked to susceptibility of chronic obstructive pulmonary disease (COPD), a smoking-related disorder that originates in the airway epithelium. Objectives: Since airway basal cell (BC) stem/progenitor cells exhibit the earliest abnormalities associated with smoking (hyperplasia, squamous metaplasia), we hypothesized that smoker BC have a dysregulated transcriptome linked, in part, to known GWAS/candidate gene loci. Methods: Massive parallel RNA sequencing was used to compare the transcriptome of BC purified from the airway epithelium of healthy nonsmokers (n=10) and smokers (n=7). The chromosomal location of the differentially expressed genes was compared to loci identified by GWAS and candidate gene studies to confer risk for COPD. Measurements and Main Results: Smoker BC have 676 known genes differentially expressed compared to nonsmoker BC, dominated by smoking up-regulation. Strikingly, 166 (25%) of these genes are located on chromosome 19, with 13 localized to 19q13.2 (p<10-4 compared to chance), including TGFB1, LTBP4, EGLN2 and NFKBIB, genes associated with risk for COPD. Conclusions: These observations provide the first direct link of known genetic risks for smoking-related lung disease with the specific population of lung cells that undergoes the earliest changes associated with smoking. The human airway basal cell transcriptome of 7 smokers versus 10 nonsmokers was compared using massive parallel RNA sequencing (Illumina HiSeq 2000).