Mechanical compression reduces CC16 expression and disrupts metabolic homeostasis in airway epithelial cells

Recent evidence suggests that bronchial epithelial cells from individuals with asthma exhibit altered metabolic signatures. This metabolic shift of energetically demanding cells leads to increased inflammation, excessive reactive oxygen species production (ROS), and oxidative stress-all hallmarks of mitochondrial dysfunction. While mitochondrial dysfunction has been implicated in disruption in epithelial cell function in asthma, the mechanistic link between bronchoconstriction observed in asthma and these metabolic alterations remains poorly defined. Club cell secretory protein (CC16) is the most abundant protein found in the lung and exerts key anti-inflammatory and antioxidant functions contributing to protection against airway remodeling. Decreased levels of CC16 in both serum and bronchial alveolar lavage fluid (BALF) are characteristic of asthma and worsening respiratory disease. Using a well-established transmembrane compression system to model bronchoconstriction coupled with mass spectrometry and quantitative proteomics, we investigated how modeling bronchoconstriction in airway cells impacts CC16 expression and cell metabolic pathway changes over time. Using naive mouse tracheal epithelial cells (MTECs) and normal human bronchial epithelial cells (HBECs), we observed that recombinant (r)CC16 induces the expression of proteins related to various metabolic pathways, such as glycolysis, gluconeogenesis, and the pentose phosphate pathway and that compression of airway cells results in acute decreases in CC16 expression, as well as decreases in metabolic processes. MTECs deficient in CC16 (CC16-/-) had lower mitochondrial oxygen consumption rate (OCR) compared to WT cells. Exogenous addition of rCC16 significantly increased OCR of both WT and CC16 deficient MTECs. Our findings suggest a novel role for CC16 in mediating airway epithelial cell metabolic processes, which could be decreased by bronchoconstrictive events in human asthma. The mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD067703.