Signalling via the osteopontin and high mobility group box-1 axis drives the fibrogenic response to liver injury

Gut. 2017 Jun;66(6):1123-1137. doi: 10.1136/gutjnl-2015-310752. Epub 2016 Jan 27.


Objective: Liver fibrosis is associated with significant collagen-I deposition largely produced by activated hepatic stellate cells (HSCs); yet, the link between hepatocyte damage and the HSC profibrogenic response remains unclear. Here we show significant induction of osteopontin (OPN) and high-mobility group box-1 (HMGB1) in liver fibrosis. Since OPN was identified as upstream of HMGB1, we hypothesised that OPN could participate in the pathogenesis of liver fibrosis by increasing HMGB1 to upregulate collagen-I expression.

Design and results: Patients with long-term hepatitis C virus (HCV) progressing in disease stage displayed enhanced hepatic OPN and HMGB1 immunostaining, which correlated with fibrosis stage, whereas it remained similar in non-progressors. Hepatocyte cytoplasmic OPN and HMGB1 expression was significant while loss of nuclear HMGB1 occurred in patients with HCV-induced fibrosis compared with healthy explants. Well-established liver fibrosis along with marked induction of HMGB1 occurred in CCl4-injected OpnHep transgenic yet it was less in wild type and almost absent in Opn-/- mice. Hmgb1 ablation in hepatocytes (Hmgb1ΔHep) protected mice from CCl4-induced liver fibrosis. Coculture with hepatocytes that secrete OPN plus HMGB1 and challenge with recombinant OPN (rOPN) or HMGB1 (rHMGB1) enhanced collagen-I expression in HSCs, which was blunted by neutralising antibodies (Abs) and by Opn or Hmgb1 ablation. rOPN induced acetylation of HMGB1 in HSCs due to increased NADPH oxidase activity and the associated decrease in histone deacetylases 1/2 leading to upregulation of collagen-I. Last, rHMGB1 signalled via receptor for advanced glycation end-products and activated the PI3K-pAkt1/2/3 pathway to upregulate collagen-I.

Conclusions: During liver fibrosis, the increase in OPN induces HMGB1, which acts as a downstream alarmin driving collagen-I synthesis in HSCs.


Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Acetylation / drug effects
  • Animals
  • Antibodies, Neutralizing
  • Carbon Tetrachloride
  • Case-Control Studies
  • Cell Nucleus / chemistry
  • Cells, Cultured
  • Collagen Type I / metabolism*
  • Cytoplasm / chemistry
  • Disease Progression
  • Gene Expression
  • HMGB1 Protein / analysis
  • HMGB1 Protein / genetics*
  • HMGB1 Protein / metabolism*
  • Hepatic Stellate Cells / metabolism
  • Hepatitis C, Chronic / complications
  • Hepatocytes / chemistry
  • Histone Deacetylase 1 / metabolism
  • Histone Deacetylase 2 / metabolism
  • Humans
  • Liver Cirrhosis / etiology
  • Liver Cirrhosis / metabolism*
  • Liver Cirrhosis / pathology
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • NADPH Oxidases / metabolism
  • Osteopontin / analysis
  • Osteopontin / genetics*
  • Osteopontin / metabolism*
  • Phosphatidylinositol 3-Kinase / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Receptor for Advanced Glycation End Products / metabolism
  • Recombinant Proteins / pharmacology
  • Signal Transduction


  • Antibodies, Neutralizing
  • Collagen Type I
  • HMGB1 Protein
  • Receptor for Advanced Glycation End Products
  • Recombinant Proteins
  • Osteopontin
  • Carbon Tetrachloride
  • NADPH Oxidases
  • Phosphatidylinositol 3-Kinase
  • Proto-Oncogene Proteins c-akt
  • Histone Deacetylase 1
  • Histone Deacetylase 2