In addition, aerobic exercise decreased both expression and phosphorylation of STAT3 in three different lung compartments, peribronchial leukocytes (which are relevant to underlying mechanisms of smoke-induced bronchitis), parenchymal leukocytes (which are relevant to underlying mechanisms of smoke-induced lung emphysema), and also by airway epithelial cells (which revealed to be an important source of STAT3 expression and activation in a model of smoke-induced COPD) [3]. The gene discussed is STAT3; the disease is chronic obstructive pulmonary disease.