Subcellular proteome analysis unraveled annexin A2 related to immune liver fibrosis

It is important to study the mechanism of liver fibrogenesis, and find new non-invasive biomarkers. In this study, we used subcellular proteomic technology to study the plasma membrane (PM) proteins related to immune liver fibrosis and search for new non-invasive biomarkers. A rat liver fibrosis model was induced by pig serum injection. The liver fibrogenesis from stage (S) S0-1, S2, S3-4, and S4 was detected by Masson staining and HE staining in this rat model after 2, 4, 6, and 8 weeks of treatment. The liver PM was enriched and analyzed using subcellular proteomic technology. The differentially expressed proteins were verified by Western blotting, immunohistochemistry, and ELISA. PM with 149-fold purification was obtained and 22 differentially expressed proteins were identified. Of which, annexin A2 (ANXA2) was detected to be increased obviously in S4 compared with S0-1, and verified by Western blotting of rat liver tissue and immunohistochemistry of rat and human liver tissue. The expression of ANXA2 in human plasma with S1-2 was also found to be up-regulated for 1.4-fold than that in S0. Furthermore, ANXA2 was detected to translocate from nuclear membrane and cytosol to PM as HBV stimulation through immunocytochemical analysis in vitro. This study identified 22 differentially expressed proteins related to liver fibrosis, and verified a potential biomarker (ANXA2) for non-invasive diagnosis of immune liver fibrosis. To our knowledge, it was the first time to dynamically study the proteins related to liver fibrosis and select biomarkers for liver fibrosis diagnosis through PM proteome research.