Endosomal translocation of CpG-oligodeoxynucleotides inhibits DNA-PKcs-dependent IL-10 production in macrophages

J Immunol. 2008 Jan 15;180(2):809-16. doi: 10.4049/jimmunol.180.2.809.


Synthetic oligodeoxynucleotides containing unmethylated CpG motifs (CpG-ODNs) function as powerful immune adjuvants by activating macrophages, dendritic cells, and B cells. However, the molecular recognition mechanism that initiates signaling in response to CpG-ODN has not fully been identified. We show in this study that peritoneal macrophages from SCID mice having mutations in the catalytic subunit of DNA-protein kinase (DNA-PKcs) were almost completely defective in the production of IL-10 and in ERK activation when treated with CpG-ODN. In contrast, IL-12 p70 production significantly increased. Furthermore, small interfering RNA (siRNA)-mediated knockdown of DNA-PKcs expression in the mouse monocyte/macrophage cell line RAW264.7 led to reduced IL-10 production and ERK activation by CpG-ODN. IL-10 and IL-12 p70 production, but not ERK activation, are blocked by chloroquine, an inhibitor of endosomal acidification. Endosomal translocation of CpG-ODN in a complex with cationic liposomes consisting of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) (CpG-DOTAP-liposomes) decreased IL-10 production and ERK activation, whereas the endosomal escape of CpG-ODN in a complex with cationic liposomes consisting of DOTAP and dioleyl-phosphatidylethanolamine (DOPE) (CpG-DOTAP/DOPE-liposomes) increased. In contrast, IL-12 p70 production was increased by CpG-DOTAP-liposomes and decreased by CpG-DOTAP/DOPE-liposomes. IL-10 production induced by CpG-DOTAP/DOPE-liposomes was not observed in macrophages from SCID mice. Thus, our findings suggest that DNA-PKcs in the cytoplasm play an important role in CpG-ODN-induced production of IL-10 in macrophages. In addition, DNA-PKcs-mediated production of IL-10 and IL-12 p70 can be regulated by manipulating the intracellular trafficking of CpG-ODN in macrophages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • DNA-Activated Protein Kinase / antagonists & inhibitors
  • DNA-Activated Protein Kinase / genetics
  • DNA-Activated Protein Kinase / metabolism*
  • DNA-Binding Proteins / antagonists & inhibitors
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Endocytosis
  • Endosomes / metabolism*
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Fatty Acids, Monounsaturated / chemistry
  • Fatty Acids, Monounsaturated / metabolism
  • Interleukin-10 / biosynthesis*
  • Interleukin-12 / metabolism
  • Liposomes / chemistry
  • Macrophages, Peritoneal / enzymology
  • Macrophages, Peritoneal / immunology*
  • Mice
  • Mice, SCID
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Oligodeoxyribonucleotides / metabolism*
  • Quaternary Ammonium Compounds / chemistry
  • Quaternary Ammonium Compounds / metabolism
  • RNA, Small Interfering / pharmacology


  • CPG-oligonucleotide
  • DNA-Binding Proteins
  • Fatty Acids, Monounsaturated
  • Liposomes
  • Nuclear Proteins
  • Oligodeoxyribonucleotides
  • Quaternary Ammonium Compounds
  • RNA, Small Interfering
  • Interleukin-10
  • Interleukin-12
  • DNA-Activated Protein Kinase
  • Prkdc protein, mouse
  • Extracellular Signal-Regulated MAP Kinases
  • 1,2-dioleoyloxy-3-(trimethylammonium)propane