CpG stimulation of primary mouse B cells is blocked by inhibitory oligodeoxyribonucleotides at a site proximal to NF-kappaB activation

Antisense Nucleic Acid Drug Dev. 2001 Aug;11(4):247-56. doi: 10.1089/108729001317022241.

Abstract

Bacterial DNA and CpG-oligodeoxyribonucleotides (ODN) are powerful B cell activators, inducing apoptosis protection, cell cycle entry, proliferation, costimulatory molecule expression, immunoglobulin (Ig) and interleukin-6 (IL-6) secretion. However, proximal events in B cell activation by ODN are only partially characterized, including the translocation of NF-kappaB to the nucleus. In this paper, we provide evidence that CpG-ODN-induced cell cycle entry and apoptosis protection are blocked by SN50 or gliotoxin and thus require NF-kappaB activation. NF-kappaB activation occurred within 30 minutes of stimulation of murine B cells with a phosphorothioate (S) CpG-ODN and persisted for up to 40 hours, with p50, p65, and c-Rel as the major components. Similar to other NF-kappaB inducers, CpG-ODN caused an early IkappaBalpha and IkappaBbeta degradation plus cleavage of the p50 precursor and subsequent NF-kappaB nuclear translocation. A group of closely related S-ODN, which specifically blocked CpG-induced B cell activation at submicromolar concentrations, also prevented NF-kappaB DNA binding and transcriptional activation. These inhibitory S-ODN differed from stimulatory S-ODN by having 2-3 G substitutions in the central motif. As inhibitory S-ODN did not directly interfere with the NF-kappaB DNA binding but prevented CpG-induced NF-kappaB nuclear translocation of p50, p65, and c-Rel and blocked p105, IkappaBalpha, and IkappaBbeta degradation, we concluded that their putative target must lie upstream of inhibitory kinase (IKK) activation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Active Transport, Cell Nucleus / drug effects
  • Animals
  • Apoptosis / drug effects
  • B-Lymphocytes / drug effects*
  • B-Lymphocytes / immunology
  • Binding Sites
  • Cell Cycle / drug effects
  • Cells, Cultured
  • CpG Islands / physiology*
  • Cysteine Endopeptidases
  • DNA / metabolism
  • DNA-Binding Proteins / metabolism
  • Depression, Chemical
  • Female
  • Gene Expression Regulation / drug effects
  • Gliotoxin / pharmacology
  • I-kappa B Proteins*
  • Lymphocyte Activation / drug effects
  • Macrophages / metabolism
  • Mice
  • Multienzyme Complexes / antagonists & inhibitors
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • Oligodeoxyribonucleotides / pharmacology*
  • Peptides / pharmacology
  • Protease Inhibitors / pharmacology
  • Proteasome Endopeptidase Complex
  • Protein Binding / drug effects
  • Protein Transport / drug effects
  • Recombinant Fusion Proteins / physiology
  • Specific Pathogen-Free Organisms
  • Transcription, Genetic / drug effects
  • Transfection

Substances

  • DNA-Binding Proteins
  • I kappa B beta protein
  • I-kappa B Proteins
  • Multienzyme Complexes
  • NF-kappa B
  • Nfkbia protein, mouse
  • Oligodeoxyribonucleotides
  • Peptides
  • Protease Inhibitors
  • Recombinant Fusion Proteins
  • SN50 peptide
  • NF-KappaB Inhibitor alpha
  • Gliotoxin
  • DNA
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex