STING1 and chronic obstructive pulmonary disease: In COPD induced by exposing mice to high levels of cigarette smoke, mitochondrial DNA (mtDNA) release from respiratory tract injury activates the cGAS-STING-IRF3 pathway to cause an excessive inflammatory response and exacerbate lung injury; however, the pathway is inhibited in cGAS-deficient (cGAS−/−) and STING-deficient (STING−/−) mice [76].