Long non-coding RNA TUG1 promotes airway remodelling by suppressing the miR-145-5p/DUSP6 axis in cigarette smoke-induced COPD

Abstract

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease that is primarily caused by cigarette smoke (CS)-induced chronic inflammation. In this study, we investigated the function and mechanism of action of the long non-coding RNA (lncRNA) taurine-up-regulated gene 1 (TUG1) in CS-induced COPD. We found that the expression of TUG1 was significantly higher in the sputum cells and lung tissues of patients with COPD as compared to that in non-smokers, and negatively correlated with the percentage of predicted forced expiratory volume in 1 second. In addition, up-regulation of TUG1 was observed in CS-exposed mice, and knockdown of TUG1 attenuated inflammation and airway remodelling in a mouse model. Moreover, TUG1 expression was higher in CS extract (CSE)-treated human bronchial epithelial cells and lung fibroblasts, whereas inhibition of TUG1 reversed CSE-induced inflammation and collagen deposition in vitro. Mechanistically, TUG1 promoted the expression of dual-specificity phosphatase 6 (DUSP6) by sponging miR-145-5p. DUSP6 overexpression reversed TUG1 knockdown-mediated inhibition of inflammation and airway remodelling. These findings suggested an important role of TUG1 in the pathological alterations associated with CS-mediated airway remodelling in COPD. Thus, TUG1 may be a promising therapeutic target in CS-induced airway inflammation and fibroblast activation.