Identification of ANXA2 (annexin A2) as a specific bleomycin target to induce pulmonary fibrosis by impeding TFEB-mediated autophagic flux. Issue 2 (1st February 2018)

• Record Type: Journal Article
• Authors: Wang, Kui; Zhang, Tao; Lei, Yunlong; Li, Xuefeng; Jiang, Jingwen; Lan, Jiang; Liu, Yuan; Chen, Haining; Gao, Wei; Xie, Na; Chen, Qiang; Zhu, Xiaofeng; Liu, Xiang; Xie, Ke; Peng, Yong; Nice, Edouard C.; Wu, Min; Huang, Canhua; Wei, Yuquan
• Is Part Of: Autophagy. Volume 14:Issue 2(2018)
• Page Start: 269
• Page End: 282
• Publication Date: 2018-02-01
• Subjects: Annexin A2 -- autophagy -- bleomycin -- chemical proteomics -- pulmonary fibrosis -- transcription factor EB; Autophagic vacuoles -- Periodicals; Apoptosis -- Periodicals; Cell death -- Periodicals; Lysosomes -- Periodicals; Degeneration (Pathology) -- Periodicals; Autophagy -- Periodicals; Cell Death -- Periodicals; Lysosomes -- Periodicals; Periodicals; 571.936
• DOI: 10.1080/15548627.2017.1409405
• Languages: English
• ISSNs: 1554-8627

Abstract

ABSTRACT: Bleomycin 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 ANXA2 E139A 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 autophagic flux. Pharmacological activation of TFEB elevates bleomycin-initiated autophagic flux, inhibits apoptosis and proliferation of epithelial cells, and ameliorates pulmonary fibrosis in bleomycin-treated mice. Notably, we observe lowered TFEB and LC3B levels in human pulmonary fibrosis tissues compared to normal controls, suggesting a critical role of TFEB-mediated autophagy in pulmonary fibrosis. Collectively, our data demonstrate that ANXA2 is a specific bleomycin target, and bleomycin binding with ANXA2 impedes TFEB-induced autophagic flux, leading to induction of pulmonary fibrosis. Our findings provide insight into the mechanisms of bleomycin-induced fibrosis and may facilitate development of optimized bleomycin therapeutics devoid of lung toxicity.