Upregulation of MCAM in primary bronchial epithelial cells from patients with COPD.

An increasing body of evidence indicates that the bronchial epithelium plays a crucial role in the pathophysiology of chronic obstructive pulmonary disease (COPD). The aim of this study was to identify new genes whose bronchoepithelial expression is specifically altered in COPD patients. Primary bronchial epithelial cell (PBEC) cultures were established from exsmokers with stable airflow limitation and never smokers. Complementary deoxyribonucleic acid array technology was used to investigate the differential expression of 847 cytokine and cytokine-related genes between the two groups. Statistical analysis was performed by means of significance analysis of microarrays and Bonferroni-corrected analysis of variance on ranks. Discriminant analysis and light cycler measurements as well as flow cytometry and Western blotting were used to confirm the significance of the array results at both the messenger ribonucleic acid (mRNA) and protein expression levels. With respect to array experiments, melanoma cell adhesion molecule (MCAM) was identified as the sole gene showing highly significant upregulation in PBECs from COPD patients compared to never smokers. Light cycler measurements confirmed these results, revealing a 2.9-fold and 2.0-fold increase in MCAM mRNA expression in COPD patients compared to nonsmokers and smokers, respectively. In addition, these differences are associated with higher median protein expression levels. These results strongly suggest involvement of melanoma cell adhesion molecule in the pathophysiology of the chronic airway inflammation seen in patients with chronic obstructive pulmonary disease.