Current therapies for chronic obstructive pulmonary disease (COPD) alleviate symptoms, but do not deal with disease progression. Respiratory mucus is primarily made up of mucins, of which mucin 5AC (MUC5AC) is the most predominant in COPD. It was hypothesized that mitochondria may control the expression of MUC5AC in COPD airway epithelium by modulating intracellular reactive oxygen species (ROS) levels.