Secondhand vape exposure regulation of CFTR and immune function in cystic fibrosis.

Background: Secondhand smoke exposure (SHSe) is a public health threat for people with cystic fibrosis (CF) and other lung diseases. Primary smoking reduces CFTR channel function, the causative defect in CF. We reported that SHSe worsens respiratory and nutritional outcomes in CF by disrupting immune responses and metabolic signaling. Recently, electronic cigarette (e-cigs) usage by caregivers and peers has increased rapidly, causing new secondhand e-cig vape exposures. Primary vaping is associated with immunologic deficits in healthy people, but it is unknown if e-cigs similarly impacts CF immune function or how it differs from SHSe. Methods: Human CF and non-CF blood monocyte derived macrophages (MDMs) and bronchial epithelial cells (HBECs) were exposed to flavored and unflavored e-cigs. The effect of e-cigs on CFTR expression and function, bacterial killing, cytokine signaling, lipid mediators, and metabolism was measured during treatment with CFTR modulators. Results: E-cigs decreased CFTR expression and function in CF and non-CF MDMs and negated CFTR functional restoration by elexacaftor/tezacaftor/ivacaftor (ETI). E-cigs also negated the restoration of anti-inflammatory PGD₂ expression in CF MDMs treated with ETI compared to controls. Flavored but not unflavored e-cigs increased pro-inflammatory cytokine expression in CF MDMs and e-cigs promoted glycolytic metabolism. E-cigs did not impact bacterial killing. Overall, HBECs were less impacted by e-cigs compared to MDMs. Conclusion: E-cigs reduced macrophage CFTR expression and hindered functional CFTR restoration by CFTR modulators, promoting a glycolytic, pro-inflammatory state. E-cigs are an emerging public health threat that may limit the efficacy of CFTR modulators in people with CF.