Airway Epithelial cGAS Is Critical for Induction of Experimental Allergic Airway Inflammation

DNA damage could lead to the accumulation of cytosolic DNA, and the cytosolic DNA-sensing pathway has been implicated in multiple inflammatory diseases. However, the role of cytosolic DNA-sensing pathway in asthma pathogenesis is still unclear. This article explored the role of airway epithelial cyclic GMP-AMP synthase (cGAS), the major sensor of cytosolic dsDNA, in asthma pathogenesis. Cytosolic dsDNA accumulation in airway epithelial cells (ECs) was detected in the setting of allergic inflammation both in vitro and in vivo. Mice with cGAS deletion in airway ECs were used for OVA- or house dust mite (HDM)-induced allergic airway inflammation. Additionally, the effects of cGAS knockdown on IL-33-induced GM-CSF production and the mechanisms by which IL-33 induced cytosolic dsDNA accumulation in human bronchial epithelial (HBE) cells were explored. Increased accumulation of cytosolic dsDNA was observed in airway epithelium of OVA- or HDM-challenged mice and in HBE cells treated with IL-33. Deletion of cGAS in the airway ECs of mice significantly attenuated the allergic airway inflammation induced by OVA or HDM. Mechanistically, cGAS participates in promoting T_H2 immunity likely via regulating the production of airway epithelial GM-CSF. Furthermore, Mito-TEMPO could reduce IL-33-induced cytoplasmic dsDNA accumulation in HBE cells possibly through suppressing the release of mitochondrial DNA into the cytosol. In conclusion, airway epithelial cGAS plays an important role via sensing the cytosolic dsDNA in asthma pathogenesis and could serve as a promising therapeutic target against allergic airway inflammation.