Mammalian DNA is an endogenous danger signal that stimulates local synthesis and release of complement factor B.

David J. Kaczorowski, Melanie J. Scott, John P. Pibris, Amin Afrazi, Atsunori Nakao, Rebecca D. Edmonds, Sodam Kim, Joon H. Kwak, Yujian Liu, Jie Fan, Timothy R. Billiar

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Complement factor B plays a critical role in ischemic tissue injury and autoimmunity. Factor B is dynamically synthesized and released by cells outside of the liver, but the molecules that trigger local factor B synthesis and release during endogenous tissue injury have not been identified. We determined that factor B is upregulated early after cold ischemia-reperfusion in mice, using a heterotopic heart transplant model. These data suggested upregulation of factor B by damage-associated molecular patterns (DAMPs), but multiple common DAMPs did not induce factor B in RAW264.7 mouse macrophages. However, exogenous DNA induced factor B mRNA and protein expression in RAW cells in vitro, as well as in peritoneal and alveolar macrophages in vivo. To determine the cellular mechanisms involved in DNA-induced factor B upregulation we then investigated the role of multiple known DNA receptors or binding partners. We stimulated peritoneal macrophages from wild-type (WT), toll-like receptor 9 (TLR9)-deficient, receptor for advanced glycation end products (RAGE)-/- and myeloid differentiation factor 88 (MyD88)-/- mice, or mouse macrophages deficient in high-mobility group box proteins (HMGBs), DNA-dependent activator of interferon-regulatory factors (DAI) or absent in melanoma 2 (AIM2), with DNA in the presence or absence of lipofection reagent. Reverse transcription-polymerase chain reaction, Western blotting and immunocytochemical analysis were employed for analysis. Synthesis of factor B was independent of TLR9, RAGE, DAI and AIM2, but was dependent on HMGBs, MyD88, p38 and NF-κB. Our data therefore show that mammalian DNA is an endogenous molecule that stimulates factor B synthesis and release from macrophages via HMGBs, MyD88, p38 and NF-κB signaling. This activation of the immune system likely contributes to damage following sterile injury such as hemorrhagic shock and ischemia-reperfusion.

Original languageEnglish
Pages (from-to)851-860
Number of pages10
JournalMolecular medicine (Cambridge, Mass.)
Volume18
DOIs
Publication statusPublished - 2012

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics
  • Genetics(clinical)

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    Kaczorowski, D. J., Scott, M. J., Pibris, J. P., Afrazi, A., Nakao, A., Edmonds, R. D., Kim, S., Kwak, J. H., Liu, Y., Fan, J., & Billiar, T. R. (2012). Mammalian DNA is an endogenous danger signal that stimulates local synthesis and release of complement factor B. Molecular medicine (Cambridge, Mass.), 18, 851-860. https://doi.org/10.2119/molmed.2012.00011