Identification of ANXA2 (annexin A2) as a specific bleomycin target to induce pulmonary fibrosis by impeding TFEB-mediated autophagic flux

ABSTRACTBleomycin is a clinically potent anticancer drug used for the treatment of germ-cell tumors, lymphomas and squamous-cell carcinomas. Unfortunately, the therapeutic efficacy of bleomycin is severely hampered by the development of pulmonary fibrosis. However, the mechanisms underlying bleomycin-induced pulmonary fibrosis, particularly the molecular target of bleomycin, remains unknown. Here, using a chemical proteomics approach, we identify ANXA2 (annexin A2) as a direct binding target of bleomycin. The interaction of bleomycin with ANXA2 was corroborated both in vitro and in vivo. Genetic depletion of anxa2 in mice mitigates bleomycin-induced pulmonary fibrosis. We further demonstrate that Glu139 (E139) of ANXA2 is required for bleomycin binding in lung epithelial cells. A CRISPR-Cas9-engineered ANXA2E139A mutation in lung epithelial cells ablates bleomycin binding and activates TFEB (transcription factor EB), a master regulator of macroautophagy/autophagy, resulting in substantial acceleration of ...