MUC5AC and bronchitis: Dysregulation of MUC5AC, mucin in the mucus layer in bronchioles [58], is considered to be related to diseases in respiratory systems including bronchitis, wheeze, asthma, hay fever, and acute lung injury [59], and interactions between MUC5AC and inflammatory mediators (ERBB1 and IL1RN) are reported to be associated with bronchitis [60].