Apoptotic response through a high mobility box 1 protein-dependent mechanism in LPS/GalN-induced mouse liver failure and glycyrrhizin-mediated inhibition

PLoS One. 2014 Apr 1;9(4):e92884. doi: 10.1371/journal.pone.0092884. eCollection 2014.

Abstract

HMGB1 is a nuclear component involved in nucleosome stabilization and transcription regulation, but extracellularly it is able to serve as a potential late mediator of lethality. In the present study, we explored inflammation-promoting activity of HMGB1 and blockade of extracellular release of HMGB1 by glycyrrhizin (GL) in LPS/GalN-triggered mouse liver injury. At 1 to 10 h after LPS/GalN-treatment, mice were anesthetized to collect blood from heart puncture, and serum transaminase and HMGB1 were evaluated. Administration of LPS/GalN precipitated tissue injury associated with time-dependent alteration in HMGB1 serum levels. At 8 h nuclear immunoreactive products were remarkably reduced and extracellular HMGB1 expression was found exclusively in the pericentral foci. The treatment with GL significantly down-regulated the serum levels of ALT, AST, and HMGB1 in addition to the strong inhibition of tissue injury and extracellular immunoreactivity to HMGB1 and to acetylated-lysine. Furthermore, GL brought about a significant decrease in the number of apoptotic hepatocytes labeled with TUNEL-method. On the basis of these results, three apoptosis-associated genes were identified with microarray analysis and real-time PCR. The ChIP-assay revealed the binding of HMGB1 protein to Gsto1 promoter sequence in LPS/GalN-treated mice and the remarkable decrease in combined HMGB1 protein by GL. The current findings claim that a single injection of LPS/GalN might stimulate apoptosis of hepatocytes through the binding of HMGB1 protein to Gsto1 promoter region and that GL-treatment might prevent the apoptosis and inflammatory infiltrates caused with LPS/GalN-injection by disturbing the binding of HMGB1 protein to Gsto1 promoter sequence.

MeSH terms

  • Acetylation / drug effects
  • Alanine Transaminase / blood
  • Animals
  • Apoptosis / drug effects*
  • Apoptosis / genetics
  • Aspartate Aminotransferases / blood
  • Carrier Proteins / genetics
  • Dendritic Cells / drug effects
  • Dendritic Cells / metabolism
  • Extracellular Space / metabolism
  • Galactosamine
  • Gene Expression Regulation / drug effects
  • Glutathione Transferase / genetics
  • Glycyrrhizic Acid / pharmacology*
  • HMGB1 Protein / metabolism*
  • Histone Deacetylases / metabolism
  • Kupffer Cells / drug effects
  • Kupffer Cells / metabolism
  • Lipopolysaccharides
  • Liver Failure / blood
  • Liver Failure / chemically induced*
  • Liver Failure / pathology*
  • Male
  • Mice, Inbred BALB C
  • Promoter Regions, Genetic / genetics
  • Protein Binding / drug effects
  • Protein Transport
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptor for Advanced Glycation End Products / genetics
  • Receptor for Advanced Glycation End Products / metabolism
  • Time Factors
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism

Substances

  • Ager protein, mouse
  • Carrier Proteins
  • Gsto1 protein, mouse
  • HMGB1 Protein
  • Lipopolysaccharides
  • RNA, Messenger
  • Receptor for Advanced Glycation End Products
  • Toll-Like Receptor 4
  • Glycyrrhizic Acid
  • Galactosamine
  • Glutathione Transferase
  • Aspartate Aminotransferases
  • Alanine Transaminase
  • Histone Deacetylases

Grants and funding

The authors have no support or funding to report.