CTSB and pulmonary emphysema: Among other overlapping DEGs, TREM2 has been observed to promote macrophage survival in the lung [47], nimA-related protein kinase 6 (NEK6) has been implicated in COPD-associated ciliopathies [48], and cathepsin B (CTSB) induced emphysema and secretory cell hyperplasia upon intratracheal administration to hamster lungs [49].