Project description:Chronic obstructive pulmonary disease (COPD) is one of the most prevalent lung diseases, and involves persistent airflow limitation and incorporates both emphysema and chronic bronchitis. Cigarette smoking has been identified as the main risk factor for disease development and progression. In a basic model of COPD, the disease is initiated when the physiologic response mechanisms to cigarette smoke exposure are overwhelmed; for example, because of long-term exposure effects or other aging-related changes. In this parallel-group case-controlled clinical study we asked to what extent the different transitions in a chronic-exposure-to-disease model are reflected in the proteome and cellular transcriptome of induced sputum samples from the lung. For this, we selected 60 age- and gender-matched individuals for each of four study groups: current healthy smokers, current-smoker COPD patients, former smokers, and never smokers (a total of 240 individuals). Induced sputum was collected, the cell-free supernatant was analyzed by quantitative proteomics (isobaric-tag based), and the cellular mRNA fraction was analyzed by microarray-based expression profiling. The sputum proteome of current smokers (healthy or COPD patients) clearly reflected the common physiological responses to smoke exposure, including alterations in mucin/trefoil proteins (e.g., MUC5AC and TFF1/3up-regulation), peptidase regulators (e.g., TIMP1 up-regulation), and a prominent xenobiotic/oxidative stress response (e.g., NQO1 and ALDH3A1 up-regulation). The latter response also was observed in the sputum transcriptome, which additionally demonstrated an immune-related polarization change (toward a M2 signature). The (long-term) former smoker group showed nearly complete reversal of the observable biological effects. Thirteen differentially abundant proteins between the COPD and healthy smoker groups were identified. These abundant proteins included previously reported COPD-associated proteins (e.g., TIMP1 (up-regulation) and APOA1 (down-regulation)) and novel proteins such as C6orf58 and BPIFB1 (LPLUNC1) (both up-regulated in the COPD group compared with the healthy smokers). In summary, our study demonstrates that sputum proteomics/transcriptomics can capture the complex and reversible physiological response to cigarette smoke exposure, which appears to be only slightly modulated in early-stage COPD patients. The study has been registered on ClinicalTrials.gov with identifier NCT01780298.

Project description:The apical junctional complex (AJC), composed of tight junctions and adherens junctions, is essential for maintaining epithelial barrier function. Since cigarette smoking and chronic obstructive pulmonary disease (COPD), the major smoking-induced disease, are both associated with increased lung epithelial permeability, we hypothesized that smoking alters the transcriptional program regulating AJC integrity in the small airway epithelium (SAE), the primary site of pathological changes in COPD. Transcriptome analysis revealed a global down-regulation of physiological AJC gene expression in the SAE of healthy smokers (n=53) compared to healthy nonsmokers (n=59), an observation associated with changes in molecular pathways regulating epithelial differentiation such as PTEN signaling and accompanied by induction of cancer-related AJC genes. Genome-wide co-expression analysis identified a smoking-sensitive AJC transcriptional network. The overall expression of AJC-associated genes was further decreased in COPD smokers (n=23). Exposure of human airway epithelial cells to cigarette smoke extract in vitro resulted in down-regulation of several AJC-related genes, accompanied by decreased transepithelial resistance. Thus, cigarette smoking alters the AJC gene expression architecture in the human airway epithelium, providing a molecular basis for the dysregulation of airway epithelial barrier function during the development of smoking-induced lung disease. The apical junctional complex (AJC), composed of tight junctions and adherens junctions, is essential for maintaining epithelial barrier function. Since cigarette smoking and chronic obstructive pulmonary disease (COPD), the major smoking-induced disease, are both associated with increased lung epithelial permeability, we hypothesized that smoking alters the transcriptional program regulating AJC integrity in the small airway epithelium (SAE), the primary site of pathological changes in COPD. In this study, microarray analysis of the SAE obtained from 53 healthy nonsmokers, 59 healthy smokers, and 23 smokers with COPD was performed to determine physiological AJC gene expression architecture in the SAE and its modification by cigarette smoking and during the development of COPD.

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Single-cell Transcriptome Analysis Reveals an Anomalous Epithelial Variation and Ectopic Inflammatory Response in Chronic Obstructive Pulmonary Disease

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