Airway gene expression is dynamic with corticosteroid treatment and reflects disease activity

Introduction: In the recently completed Dutch GLUCOLD study, treatment of COPD patients with fluticasone salmeterol reduced the rate of decline in FEV1. These results indicate that ICS can have therapeutic efficacy in COPD. Aim: To explore the molecular mechanisms by which ICS exert their effects, we performed genome-wide gene expression profiling on bronchial biopsies from COPD patients who participated in the GLUCOLD study. Methods: An Affymetrix Human Gene Array ST version 1.0 was performed in a total of 221 bronchial biopsies that were available from 90 COPD patients at baseline and after 6 and 30 months of therapy. Linear mixed effects modeling was used to analyze treatment-specific changes in gene expression. A validation set was included and pathway analysis was performed with Gene Set Enrichment Analysis (GSEA). Results: The expression of 138 genes significantly decreased after both 6 and 30 months of treatment with fluticasone salmeterol versus placebo, whereas the expression of 140 genes increased. A more pronounced treatment-induced change in expression of 51 of these 278 genes was associated with a slower rate of decline in FEV1. Genes that decreased with treatment were involved in pathways related to cell cycle, oxidative phosphorylation, epithelial cell signaling, p53 signaling and T cell signaling. Genes that increased with treatment were involved in pathways related to focal adhesion, gap junction and extracellular matrix deposition. Conclusion: The present study suggests that gene expression in biological pathways of COPD is dynamic with treatment and reflects disease activity. This study opens the gate to targeted and phenotype-driven therapy of COPD.

221

van den Berge M, Steiling K, Timens W, Hiemstra PS, Sterk PJ, Heijink IH, Liu G, Alekseyev YO, Lenburg ME, Spira A, Postma DS