In the COPD mouse model, blocking NETs-DNA-sensing via cGAS−/− and TLR9−/− mice, inhibiting NETosis using mitoTEMPO, and degrading NETs-DNA with DNase-I, respectively, reduced NETs infiltrations, airway inflammation, NF-κB activation and NF-κB-dependent cytokines, but not type-I interferons due to IFN-α/β receptor degradation. Here, TLR9 is linked to chronic obstructive pulmonary disease.