Environmental
cadmium (Cd) exposure can cause several
pulmonary diseases. Epithelial-mesenchymal transition (EMT) involved in the process of
chronic obstructive pulmonary disease (
COPD). However, the association between environmental Cd exposure and EMT was unclear in
COPD patients. This study aimed to analyze the associations among circulatory Cd, EMT and
COPD based on case-control study. Four hundred
COPD patients and 400 control subjects were recruited. Circulatory Cd was detected using atomic adsorption spectrometer. MicroRNA-30 (miR-30) was measured by RT-PCR and the markers of pulmonary EMT were evaluated through western blotting. Circulatory Cd concentration was increased and serum miR-30 was decreased in
COPD patients. Circulatory Cd was inversely associated with pulmonary function in
COPD patients. Moreover, serum miR-30 was gradually decreased in parallel with FEV1 in
COPD patients. Meanwhile, there was a negative association between serum miR-30 and circulatory Cd in
COPD patients. Further analysis found that
E-cadherin, one of epithelial
biomarkers, was reduced in lung tissues of
COPD patients with higher circulatory Cd. On the contrary, pulmonary
N-cadherin,
Vimentin and α-SMA, three of mesenchymal
biomarkers, were increased in
COPD patients with higher circulatory Cd. In vitro experiments revealed that Cd exposure repressed miR-30 levels and promoted EMT in BEAS-2B cells. Our results provide evidence that miR-30 reduction contributing to pulmonary EMT may involve in the process of Cd-induced
COPD.