DACH1 Attenuates Airway Inflammation in COPD by Activating NRF2 Signaling.

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the airways, it is characterized by impaired lung function induced by cigarette smoke (CS). Reduced DACH1 expression has a detrimental role in numerous disorders. However, its role in COPD remains understudied. This study aims to elucidate the role and underlying mechanism of DACH1 in airway inflammation of COPD. DACH1 expression was measured in lung tissues of patients with COPD. Airway epithelium-specific DACH1 knockdown mice and AAV-transfected DACH1 overexpressed mice were used to investigate its role and potential for therapeutic targeting in experimental COPD caused by CS. Furthermore, we discovered a potential mechanism of DACH1 in inflammation induced by cigarette smoke extract simulation (CSE) in vitro. Compared to non-smokers and smokers without COPD, COPD patients had reduced DACH1 expression, especially in the airway epithelium. Airway epithelium-specific DACH1 knockdown aggravated mice airway inflammation and lung function decline caused by CS, whereas DACH1 overexpression protected mice from airway inflammation and lung function decline. DACH1 knockdown and overexpression promoted and inhibited IL-6 and IL-8 secretion in 16 HBE cells after CSE simulation, respectively. Nuclear factor erythroid 2-related factor 2 (NRF2) was discovered to be a novel downstream target of DACH1, which binds directly to its promoter. By activating NRF2 signaling, DACH1 induction reduced inflammation. DACH1 levels are lower in smokers and nonsmoking COPD patients when compared to nonsmokers. DACH1 has protective effects against inflammation induced by CS by activating NRF2 signaling pathway. Targeting DACH1 is a potentially viable therapeutic approach for COPD treatment.