ERJ Open Res. 2026 Mar 9;12(2):00497-2025. doi: 10.1183/23120541.00497-2025. eCollection 2026 Mar.
ABSTRACT
RATIONALE: The mechanisms driving epithelial pathology in COPD are steadily being unveiled, confirming a role for inflammation in the disease. This study explored the interleukin (IL)-6/STAT3 axis, previously reported to link inflammation and epithelial-to-mesenchymal transition, two features of COPD at the airway epithelium level.
METHODS: Bronchoalveolar lavage fluid (BALF) and surgical lung tissue were obtained from nonsmoker controls, smokers and COPD patients. The activation of STAT3 and IL-6 levels were measured in these samples. Primary air-liquid interface (ALI) cultures were carried out from nonsmokers, smokers and COPD patients, and IL-6 release and STAT3 mRNA levels were assessed. BEAS-2B cell cultures were exposed to sputum supernatants from COPD patients versus nonsmokers, with and without a pan-gp130 blocking monoclonal antibody. Finally, primary ALI cultures from nonsmokers were exposed to IL-6 versus vehicle and assessed for epithelial-to-mesenchymal transition and cell differentiation.
RESULTS: IL-6 and Tyr705-phospho-STAT3 levels were increased in samples from COPD patients compared to controls, both in BALF and in the airway epithelium, as well as in ALI cultures. BEAS-2B cells exposed to COPD sputum supernatants displayed STAT3 activation that was inhibited by the pan-gp130 blocking monoclonal antibody. In addition, stimulation of ALI cultures with IL-6 induced increased vimentin expression and fibronectin release and reduced the expression of apical junctional complexes proteins, indicating epithelial-to-mesenchymal transition. Finally, no impact on airway cell differentiation was observed.
CONCLUSIONS: The IL-6/STAT3 axis is activated in the COPD airway epithelium, presumably contributing to epithelial-to-mesenchymal transition.
PMID:41809862 | PMC:PMC12969678 | DOI:10.1183/23120541.00497-2025