The IL-6-gp130-STAT3 pathway in hepatocytes triggers liver protection in T cell-mediated liver injury

J Clin Invest. 2005 Apr;115(4):860-9. doi: 10.1172/JCI23640. Epub 2005 Mar 3.

Abstract

Increasing evidence demonstrates that IL-6 has a protective role during liver injury. IL-6 activates intracellular pathways via the gp130 receptor. In order to identify IL-6-gp130 pathways involved in mediating liver protection, we analyzed hepatocyte-specific gp130 knockout mice in a concanavalin A-induced (Con A-induced) model of immune-mediated hepatitis. We demonstrated that IL-6-gp130-dependent pathways in hepatocytes alone are sufficient for triggering protection in Con A-induced hepatitis. gp130-STAT3 signaling in hepatocytes mediates the IL-6-triggered protective effect. This was demonstrated by analysis of IL-6-induced protection in mice selectively deficient for gp130-dependent STAT1/3 or gp130-SHP2-RAS signaling in hepatocytes. To identify IL-6-gp130-STAT1/3 dependently expressed liver-protective factors, we performed gene array analysis of hepatic gene expression in hepatocyte-specific gp130(-/-) mice as well as in gp130-STAT1/3- and gp130-SHP2-RAS-MAPK-deficient mice. The mouse IL-8 ortholog KC (also known as Gro-alpha) and serum amyloid A2 (SAA2) was identified as differentially IL-6-gp130-STAT3-regulated genes. Hepatic expression of KC and SAA2 mediate the liver-protective potential of IL-6, since treatment with recombinant KC or serum SAA2 effectively reduced liver injury during Con A-induced hepatitis. In summary, this study defines IL-6-gp130-STAT3-dependent gene expression in hepatocytes that mediates IL-6-triggered protection in immune-mediated Con A-induced hepatitis. Additionally, we identified the IL-6-gp130-STAT3-dependent proteins KC and SAA2 as new candidates for therapeutic targets in liver diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD / genetics
  • Antigens, CD / metabolism*
  • Concanavalin A / toxicity
  • Cytokine Receptor gp130
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Enzyme Activation
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Gene Expression Profiling
  • Hepatitis / immunology
  • Hepatocytes / physiology*
  • Interferon-gamma / metabolism
  • Interleukin-6 / metabolism*
  • Liver / cytology
  • Liver / drug effects
  • Liver / metabolism
  • Liver / pathology*
  • Male
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Knockout
  • STAT1 Transcription Factor
  • STAT3 Transcription Factor
  • Serum Amyloid A Protein / metabolism
  • Signal Transduction / physiology*
  • T-Lymphocytes / metabolism*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Antigens, CD
  • DNA-Binding Proteins
  • Il6st protein, mouse
  • Interleukin-6
  • Membrane Glycoproteins
  • STAT1 Transcription Factor
  • STAT3 Transcription Factor
  • Saa2 protein, mouse
  • Serum Amyloid A Protein
  • Stat1 protein, mouse
  • Stat3 protein, mouse
  • Trans-Activators
  • Tumor Necrosis Factor-alpha
  • Concanavalin A
  • Cytokine Receptor gp130
  • Interferon-gamma
  • Extracellular Signal-Regulated MAP Kinases