ACE2 and pulmonary fibrosis: Bleomycin has been used extensively in previous studies to reveal important mechanisms that promote vascular remodeling in association with lung fibrosis, including endothelin-1 (36), natriuretic peptide receptor–A (37), ACE2 (38, 39), Rho-kinase/ROCK (40), hypoxia signaling (41), adenosine signaling (42, 43), hyaluronan production (45–47), and a population of CXCR2+ myeloid-derived suppressor cells (48).