My research focuses on the role of airway epithelium in the lung. The airway epithelium is the first line of defense against external stimuli. Airway epithelial cells lining on the airway epithelium contribute to homeostasis in the lung, but when they are exposed to excessive biochemical or physical stimuli, the normal defense mechanism turns into the progression of various pathophysiologic conditions. Airway epithelial cells also play important roles in innate and adaptive immunities and inflammation.