Hence, in accordance with this line of research, it is prudent to scrutinize the signaling pathways leading to lung CatS upregulation in human macrophages exposed to cigarette smoke extract (CSE) and to examine whether CatS could participate in the modulation of the integrity of epithelial barriers in COPD, despite an unfavorable oxidizing environment. This evidence concerns the gene PIMREG and chronic obstructive pulmonary disease.