USP9X-mediated NRP1 deubiquitination promotes liver fibrosis by activating hepatic stellate cells

• Published in: Cell death & disease 2023-01, Vol.14 (1), p.40-40, Article 40
• Main Authors: Zhao, Jinqiu, Bai, Jie, Peng, Fengling, Qiu, Chan, Li, Yongguo, Zhong, Li
• Format: Article
• Language: English
• Subjects: 101/58; 13/1; 13/21; 13/51; 14/1; 14/28; 14/32; 38/32; 38/77; 631/337/641; 692/699/1503/1607; 82/81; Animal models; Animals; Antibodies; Biochemistry; Biomedical and Life Sciences; Body weight; Carbon tetrachloride; Cell activation; Cell Biology; Cell Culture; Cell Proliferation; Cirrhosis; Fibrosis; Hepatic Stellate Cells - metabolism; Hepatocytes; Humans; Immunohistochemistry; Immunology; Immunoprecipitation; Life Sciences; Liver; Liver - metabolism; Liver cirrhosis; Liver Cirrhosis - pathology; Male; Mice; Mice, Inbred C57BL; Olive oil; Olive Oil - metabolism; Platelet-derived growth factor BB; Stellate cells; Transforming growth factor-b1; Ubiquitin Thiolesterase - genetics; Ubiquitin Thiolesterase - metabolism; Ubiquitination; Western blotting
• ISSN: 2041-4889; 2041-4889
• DOI: 10.1038/s41419-022-05527-9

Liver fibrosis is a complex fibrotic process that develops early in the course of cirrhosis and is caused by chronic liver damage. The activation of hepatic stellate cells is primarily responsible for the fibrosis process. Studies show that NRP1 influences HSC motility and migration. However, whether NRP1 regulates HSC activation remains unknown. C57BL/6 male mice (6–8 weeks old) were intraperitoneally injected with 10% CCl 4 in olive oil (5 μl/g body weight) every three days for four weeks to create an animal model of liver fibrosis. Control mice received olive oil (5 μl/g body weight). Different assays such as immunohistochemistry, immunostaining, Western blotting, qRT-PCR, immunoprecipitation, immunoprecipitation, and GST pull-down assays, and in vivo and in vitro ubiquitination assays were conducted. We found that NRP1 expression was significantly elevated both in mouse and human fibrotic livers, mainly in activated HSCs at the fibrotic foci. NRP1 promoted HSC activation via the cytokine TGF-β1, VEGFA, and PDGF-BB. Moreover, USP9X was found to be a critical deubiquitinating enzyme for the stability and high activity of NRP1 and NRP1 deubiquitination mediated by USP9X enhanced HSC activation and liver fibrosis. NRP1 deubiquitination mediated by USP9X enhances HSC activation, implying that targeting NRP1 or USP9X potentiates novel options in the treatment of liver fibrosis.