Airway smooth muscle and epithelial cell signaling network (EMTU)

The airway smooth muscle and epithelial cell signaling network refers to the complex, bidirectional communication system between the respiratory epithelium and the underlying smooth muscle layer. This network is essential for maintaining airway homeostasis, regulating bronchomotor tone, and coordinating local immune responses to inhaled insults (Vliagoftis, 2002). Epithelial cells release various factors, such as epithelium-derived relaxing factors (EpDRF) and inflammatory cytokines, which directly influence the contractility and growth of airway smooth muscle (ASM) (Fernandes et al., 2003). Conversely, ASM cells can release pro-inflammatory mediators and extracellular matrix proteins that affect epithelial function and integrity (Knight & Holgate, 2003). In chronic respiratory conditions like asthma and COPD, this signaling becomes dysregulated, leading to the characteristic features of airway hyperresponsiveness, mucus hypersecretion, and structural remodeling of the airway wall (Holgate, 2007). Pharmacological management of these diseases involves targeting specific components of this network, such as using beta-2 agonists to induce ASM relaxation or corticosteroids to suppress epithelial-driven inflammation (Barnes, 2017). Because it encompasses a vast array of distinct proteins and cell-cell interactions, it is classified as a physiological system or a signaling pathway network rather than a single molecular therapeutic target.

Other names

Airway epithelial-mesenchymal trophic unitASM-epithelial crosstalkBronchial cell signaling networkEpithelial-smooth muscle unit

Modulation of specific molecular nodes within the network, including G protein-coupled receptors (beta-2 adrenergic and muscarinic receptors), leukotriene receptors, and cytokine signaling pathways (IL-4/IL-13).