Flagellin, the major structural subunit of flagella, induces the expression of MUC5AC and MUC2 when exposed to the airway epithelial cells in a TLR5/NAIP-dependent manner [92], and likely contributes to the early goblet cell hyperplasia and hyper mucus production that further contributes to CF pathology, creating an even greater opportunity for P. aeruginosa biofilm infections to spread. This evidence concerns the gene MUC5AC and cystic fibrosis.