Mucin 5AC (MUC5AC) and Mucin 5B (MUC5B) expression pathways (MUC5AC/MUC5B pathways)

Mucin 5AC (MUC5AC) and Mucin 5B (MUC5B) are the two primary gel-forming mucins in the human respiratory tract, responsible for the viscoelastic properties of airway mucus [1.1.2, 1.3.3]. MUC5B is constitutively expressed and is essential for homeostatic mucociliary clearance and innate lung defense, while MUC5AC is typically induced by inflammatory stimuli such as allergens, cigarette smoke, and viral infections [1.2.2, 1.3.1]. The expression pathways for these mucins are regulated by complex signaling networks involving the epidermal growth factor receptor (EGFR), interleukin-13 (IL-13), and transcription factors like NF-kB and Sp1 [1.2.3, 1.4.1]. Dysregulation of these pathways leads to mucus hypersecretion and plugging, which are hallmark features of chronic airway diseases like asthma, COPD, and cystic fibrosis [1.3.4, 1.3.5]. Conversely, a specific gain-of-function polymorphism in the MUC5B promoter is strongly associated with the development of idiopathic pulmonary fibrosis [1.3.3]. Therapeutic targeting of these pathways aims to normalize mucin production and improve airway clearance, though maintaining a balance is crucial to avoid compromising the lung's defensive barrier [1.2.4, 1.3.2].

Other names

Airway mucin expression pathwaysGel-forming mucin pathwaysMUC5AC and MUC5B regulatory pathwaysSecreted polymeric mucin pathways

Inhibition of mucin gene transcription (e.g., via EGFR or IL-13 blockade), modulation of goblet cell hyperplasia, disruption of mucin polymer disulfide bonds to reduce viscosity, and inhibition of mucin secretion via MARCKS protein antagonism [1.4.1, 1.2.4].