AQP5 and chronic obstructive pulmonary disease: A specific mechanism by which this interaction could occur is suggested by in vitro studies showing smoking attenuates expression of AQP5 in submucosal glands of subjects with COPD.[7] This decreased expression of human AQP5 has been associated with mucus overproduction in the airways of subjects with COPD and lower lung function.[7] Our in vitro studies confirm wildtype hAQP5 abundance decreases after exposure to CSE and low level shear stress.