As functions of lung fibroblasts are altered in COPD in multiple ways, including extracellular mediator production, gel contraction, chemotaxis and cell proliferation [8–11], we examined the role of miR-503 in modulating the production of IL-6, -8, PGE2, HGF, KGF, VEGF and fibronectin, all of which are associated with COPD pathogenesis [8, 11, 18–21]. This evidence concerns the gene IL6 and chronic obstructive pulmonary disease.