cGAS-STING drives alveolar epithelial cell dysfunction in cigarette smoke-induced lung injury

Abstract

Chronic inflammation induced by cigarette smoke (CS) plays a central role in the pathogenesis of chronic obstructive pulmonary disease (COPD), but its impact on lung epithelial progenitor function and regenerative capacity remains incompletely understood. Here, we combined in vivo and in vitro approaches to dissect how CS exposure and subsequent inflammatory insults shape epithelial repair dynamics. A 6-week whole-body CS exposure model in mice induced lung function impairment and altered gene expression profiles in alveolar epithelial cells, prominently activating interferon (IFN)-related pathways and the cGAS-STING axis. Alveolar epithelial cells from CS-exposed mice generated a similar number, but larger organoids with reduced alveolar differentiation compared to air-exposed mice. Notably, these cells obtained from CS-exposed mice displayed resistance to IFN{gamma}-induced suppression of organoid growth, contrasting with the strong inhibitory effect of IFN{gamma} observed in controls. This phenotype was recapitulated in a two-hit in vitro model using cigarette smoke extract (CSE), in which chronic CSE exposure impaired regeneration and differentiation while inducing resistance to IFN{gamma}. Gene expression and proteomic analyses revealed upregulation of Zbp1, Irf7, and other upstream IFN regulators, correlating negatively with alveolar differentiation potential. Inhibition of the cGAS-STING pathway with RU.521 partially rescued organoid formation, increased proliferation, and alveolar differentiation. Together, our data reveal that CS exposure alters the alveolar epithelial landscape, inducing a stress-adapted, IFN{gamma}-resistant state that compromises alveolar regeneration, with cGAS-STING activation as a key driver of early CS-associated alveolar type 2 cell dysfunction. These findings provide new insight into how chronic inflammation reshapes progenitor cell function during early lung injury.