Persistent activation of nuclear factor-kappaB in cultured rat hepatic stellate cells involves the induction of potentially novel Rel-like factors and prolonged changes in the expression of IkappaB family proteins

Hepatology. 1999 Sep;30(3):761-9. doi: 10.1002/hep.510300327.


Rat hepatic stellate cells (HSC) cultured in serum-containing medium underwent a rapid (3-hour) classical induction of p50:p65 and p65:p65 nuclear factor-kappaB (NF-kappaB) dimers. Subsequent culturing was associated with prolonged expression of active p50:p65 and persistent induction of a high-mobility NF-kappaB DNA binding complex consisting of potentially novel Rel-like protein(s). Formation of the latter complex was competed for by specific double-stranded oligonucleotides, was up-regulated by treatment of HSCs with tumor necrosis factor alpha (TNF-alpha), and was maintained at basal levels of expression by a soluble HSC-derived factor. An NF-kappaB-responsive CAT reporter gene was highly active in early cultured HSCs but was also trans-activated at a lower but significant level in longer-term cultured cells and could be completely suppressed by expression of dominant negative IkappaB-alpha. Physiological significance of the lower persistent NF-kappaB activities was also demonstrated by the ability of long-term cultured HSCs to support the activity of the NF-kappaB-dependent human intercellular adhesion molecule-1 (ICAM-1) promoter. Freshly isolated HSCs expressed high levels of IkappaB-alpha and IkappaB-beta. Culture activation was accompanied by a long-term reduction in levels of IkappaB-alpha with no detectable expression in the nuclear fraction of cells, under these conditions p50:p65 was detected in the nucleus. IkappaB-beta expression was transiently reduced and, upon replenishment, was associated with appearance of a lower-mobility IkappaB-beta antibody-reactive species. Bcl3 expression was absent in freshly isolated HSC but was induced during culturing and became a persistent feature of the activated HSC. Inhibition of NF-kappaB DNA binding activity by gliotoxin was associated with increased numbers of apoptotic cells. We suggest that activation of NF-kappaB in cultured HSC is required for expression of specific genes associated with the activated phenotype such as ICAM-1 and may be antiapoptotic for rat HSCs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipocytes / metabolism*
  • Animals
  • Apoptosis / drug effects
  • Cells, Cultured
  • DNA / metabolism
  • DNA-Binding Proteins / biosynthesis*
  • Gliotoxin / pharmacology
  • I-kappa B Proteins*
  • Intercellular Adhesion Molecule-1 / genetics
  • Liver / cytology
  • Liver / metabolism*
  • Male
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / metabolism*
  • Proto-Oncogene Proteins / biosynthesis*
  • Rats
  • Rats, Sprague-Dawley
  • Transcription Factor RelB
  • Transcription Factors / biosynthesis*
  • Transcription, Genetic


  • DNA-Binding Proteins
  • I-kappa B Proteins
  • NF-kappa B
  • NFKBIA protein, human
  • Nfkbia protein, rat
  • Proto-Oncogene Proteins
  • Relb protein, rat
  • Transcription Factors
  • Intercellular Adhesion Molecule-1
  • NF-KappaB Inhibitor alpha
  • Transcription Factor RelB
  • Gliotoxin
  • DNA