MUC5B and inflammation: Chronic airway inflammation in βENaC-Tg mice is associated with mucus hypersecretion, as evidenced by goblet cell metaplasia and elevated expression of secreted mucins (MUC5AC and MUC5B) that were found to be reduced in βENaC-Tg mice that lack NE (βENaC-Tg/NE-/-) [9].