[Alveolar macrophages in rats with chronic obstructive pulmonary disease (COPD) promotes proliferation, mucin and inflammatory factors secretion of airway epithelial cells and its mechanism].

Objective To explore how alveolar macrophages from chronic obstructive pulmonary disease (COPD)-model rats affect proliferation and secretion of 16HBE human bronchial epithelial cells and investigate the associated mechanism. Methods Alveolar macrophages were extracted from COPD rats induced by cigarette smoke exposure and LPS instillation through bronchoalveolar lavage, then co-cultured with 16HBE cells in vitro. Exosomes were extracted from alveolar macrophages of rats with exosome isolation kit. The differentially expressed miRNA in exosomes derived from macrophages of rats in COPD group and control group was detected by PCR. miR-380 was overexpressed with miR-380 mimic while the expression of cystic fibrosis transmembrane transduction regulator (CFTR) was knocked down with siRNA in 16HBE cells. The proliferation of 16HBE cells was detected with CCK-8 assay. The migration ability of 16HBE cells was evaluated with Transwell^TM migration assay. The levels of mucins (MUC5AC, MUC5B, MUC2) and CFTR expressed by 16HBE cells were detected with Western blot analysis. The expression of TNF-α and IL-6 in the supernatant of 16HBE cells was detected with ELISA. Results The alveolar macrophages from COPD rats enhanced the proliferation and migration of 16HBE cells. The production of mucins and TNF-α as well as IL-6 in 16HBE cells were increased by COPD macrophages. The expression of miR-380 was significantly elevated in exosomes derived from COPD alveolar macrophages. Both overexpression of miR-380 and inhibition of CFTR decreased the expression of CFTR, resulting in the significantly enhanced proliferation and migration of 16HBE cells as well as increased expression of MUC5AC, MUC5B, MUC2 and TNF-α, IL-6. Conclusion The alveolar macrophages from COPD rats can enhance the proliferation and mucin expression as well as inflammatory cytokine secretion of 16HBE cells. This process may be involved with abnormal expression of miR-380 in exosomes of COPD alveolar macrophages and down-regulation of CFTR in bronchial epithelial cells.