Yu Q, et al. - Researchers sought to assess the involvement of CD147 in mucus production in chronic obstructive pulmonary disease (COPD). Using immunohistochemistry, the expression levels of CD147 and MUC5AC were determined in 42 human lung specimens from three groups (non-smokers without COPD, smokers without COPD and smokers with COPD). For the in vitro experiment, they treated human bronchial epithelial (HBE) cells with cigarette smoke (CS) extract to establish a mucus secretion model; then, they detected CD147 and MUC5AC production by RT-PCR, Western blotting and ELISA. Smokers with COPD displayed higher CD147 and MUC5AC expression levels compared to those observed in non-smokers and smokers without COPD. The MMP9 and p38 MAPK signaling pathway in HBE cells seemed to be involved in MUC5AC secretion stimulation by increased CD147 levels induced by CS extract. These findings emphasize regulating CD147 as a promising target for mucus hypersecretion in COPD.