ARG1 and pulmonary emphysema: Next, isolated macrophages from BAL fluid in the LPS + Elastase group exhibited induced expression of Psmb8/Psmb9, M1 (Nos2, Il1b, Tnf, Cxcl1, Cxcl2, and Cxcl3) and M2 marker genes (Arg1, Mrc1, Ccl17, and Retnla) compared to the control group (Figures 1G and 2G), indicating a correlation between immunoproteasome and macrophage activation during emphysema development.