We tested the role of <i>CELA1</i> in emphysema development in this genetic model of <i>AAT</i> -deficiency following tracheal lipopolysacharide (LPS), 8 months of cigarette smoke (CS) exposure, aging, and a low-dose tracheal porcine pancreatic elastase (LD-PPE) model. Here, SERPINA1 is linked to pulmonary emphysema.