SerpinB3 Promotes Pro-fibrogenic Responses in Activated Hepatic Stellate Cells

Abstract

SerpinB3 is a hypoxia- and hypoxia-inducible factor-2α-dependent cystein protease inhibitor that is up-regulated in hepatocellular carcinoma and in parenchymal cells during chronic liver diseases (CLD). SerpinB3 up-regulation in CLD patients has been reported to correlate with the extent of liver fibrosis and the production of transforming growth factor-β1, but the actual role of SerpinB3 in hepatic fibrogenesis is still poorly characterized. In the present study we analyzed the pro-fibrogenic action of SerpinB3 in cell cultures and in two different murine models of liver fibrosis. “In vitro” experiments revealed that SerpinB3 addition to either primary cultures of human activated myofibroblast-like hepatic stellate cells (HSC/MFs) or human stellate cell line (LX2 cells) strongly up-regulated the expression of genes involved in fibrogenesis and promoted oriented migration, but not cell proliferation. Chronic liver injury by CCl4 administration or by feeding a methionine/choline deficient diet to transgenic mice over-expressing human SerpinB3 in hepatocytes confirmed that SerpinB3 over-expression significantly increased the mRNA levels of pro-fibrogenic genes, collagen deposition and αSMA-positive HSC/MFs as compared to wild-type mice, without affecting parenchymal damage. The present study provides for the first time evidence that hepatocyte release of SerpinB3 during CLD can contribute to liver fibrogenesis by acting on HSC/MFs.

Hypoxia‐inducible factor 2α drives nonalcoholic fatty liver progression by triggering hepatocyte release of histidine‐rich glycoprotein

“…The involvement of HRGP in mediating the effects of HIF‐2α activation during NAFLD progression does not rule out the possible involvement of other mediators. We previously reported that HIF‐2α activation in human liver cancer cells up‐regulates Serpin B3 and that this contributes to the development of fibrosis during CLD by sustaining the most relevant profibrogenic responses by activated stellate cells . Unfortunately, unlike in humans, SerpinB3 is virtually undetectable in murine livers during CLD; thus, in the present study we did not have the chance to evaluate its contribution to NAFLD progression.…”

“…In vitro experiments in this study were performed in normal HepG2 cells (American Type Culture Collection) as well as in cells stably transfected in order to overexpress HIF‐2α in either normoxic or hypoxic conditions, as reported . Western blot analysis was performed on total cell or tissue lysates as described . More details on in vitro studies and western blot analysis are available in the http://onlinelibrary.wiley.com/doi/10.1002/hep.29754/suppinfo.…”

“…Immunohistochemistry (IHC), (28,29) picro-sirius red staining, and histomorphometric analysis (30,31) were performed on paraffin-embedded human liver biopsies and/or murine liver specimens as reported. More details are in the Supporting Information.…”

“…RNA extraction, complementary DNA synthesis, and quantitative real-time PCRs were performed on human and murine liver specimens as described. (28)(29)(30) mRNA levels were measured by quantitative real-time PCR, using the SYBR green method as described. (28)(29)(30) More details and oligonucleotide sequences of primers used for quantitative real-time PCR are available in the Supporting Information.…”

Performance of different biomarkers for the management of hepatocellular carcinoma

“…Accordingly, levels of circulating SCCA-IgM have been recently found to increase over time, being predictive of fibrosis progression in patients with chronic hepatitis [47] . Furthermore, it has been demonstrated that HCV-infected cirrhotic patients with low levels of serum SCCA-IgM have a decreased risk of developing HCC [48] .…”