COPD is a common and disabling lung disease for which very few therapeutic options are currently available. We reasoned that global gene expression profiling of COPD lungs could reveal previously unidentified disease pathways for potential therapeutic interventions. Forty-eight human lung samples were obtained from lungs or lobes resected for small peripheral lung lesions (5 non-smokers, 21 GOLD 0, 9 GOLD 1, 10 GOLD 2 and 3 GOLD 3 patients). mRNA from the specimens was profiled using Agilent’s Functional ID v2.0 array which contains 23,720 sequences. Quantitative morphometric analysis of the specimens revealed that the samples contained a variable proportion of airways, blood vessels and parenchyma. Incorporating these data into a model relating gene expression to % predicted forced expiratory flow between 25 and 75% of forced expiratory volume (FEF 25-75 % P) revealed a signature gene set of 203 transcripts. Genes involved in extracellular matrix synthesis/degradation, oxidative stress and cell proliferation were among the up-regulated genes whereas genes which participate in nicotine metabolism, elastic fiber homeostasis and anti-inflammatory response were down-regulated. Immunohistochemistry confirmed expression of urokinase (PLAU), urokinanse receptor (PLAUR) and thrombospondin (THBS1) by alveolar macrophages and small airway epithelial cells. Genes in this pathway have been shown to be involved in transforming growth factor beta-1 (TGFβ1) and matrix metalloproteinase (MMP) activation and are subject to inhibition by serpin E2. Interestingly, both TGFβ1 and serpin E2 have been identified as candidate genes in COPD genetic linkage and association studies. The results thus provide a possible link between these two powerful approaches to identify potential therapeutic targets. (255 words) Keywords: Pulmonary emphysema, phenotype, transcriptional analysis, cigarette smoking
Overall design
Forty-eight human lung samples were obtained from lungs or lobes resected for small peripheral lung lesions (5 non-smokers, 21 GOLD 0, 9 GOLD 1, 10 GOLD 2 and 3 GOLD 3 patients). mRNA from the specimens was profiled using Agilent’s Functional ID v2.0 array which contains 23,720 sequences. Quantitative morphometric analysis of the specimens revealed that the samples contained a variable proportion of airways, blood vessels and parenchyma. Incorporating these data into a model relating gene expression to % predicted forced expiratory flow between 25 and 75% of forced expiratory volume (FEF 25-75 % P) revealed a signature gene set of 203 transcripts.
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