ROS-Responsive miR-150-5p Downregulation Contributes to Cigarette Smoke-Induced COPD via Targeting IRE1 α

MicroRNAs (miRNAs) have been reported in human diseases, in which chronic obstructive pulmonary disease (COPD) is included. Herein, we assessed the role along with the possible mechanisms of miR-150-5p in cigarette smoke- (CS-) induced COPD. The plasma miR-150-5p expression was lower in patients with COPD and acute exacerbation of COPD (AECOPD) and was related to disease diagnosis, disease severity, and lung function. Consistently, exposure to CS for 3 months or 3 days reduced miR-150-5p in the plasma and lung tissues of mice, and CS extract (CSE) inhibited miR-150-5p in human bronchial epithelial cells (HBECs) in a concentration along with time-dependent approach. In vitro, miR-150-5p overexpression decreased the contents of inflammatory factors interleukin- (IL-) 6, IL-8 along with cyclooxygenase-2 (COX-2), and endoplasmic reticulum (ER) stress markers glucose-regulated protein (GRP) 78 and C/-EBP homologous protein (CHOP) and promoted cell migrate. Mechanistically, miR-150-5p could bind with the 3'-untranslated region (UTR) of inositol requiring Enzyme 1α (IRE1α), while IRE1α overexpression obliterated the impacts of miR-150-5p. Besides, N-acetyl-cysteine (NAC) reversed CSE-induced miR-150-5p downregulation and its downstream effects. In vivo, miR-150-5p overexpression counteracted CS-triggered IRE1α upregulation, inflammation, and ER stress in the lung tissues of mice. In conclusion, our findings illustrated that ROS-mediated downregulation of miR-150-5p led to CS-induced COPD by inhibiting IRE1α expression, suggesting to serve as a useful biomarker for diagnosing and treating COPD.